Nikolay I. Kargin
Nanoelectronics, electronics based on new principles and materials, functional systems engineering
Terahertz nanophotonics: research and development of the modern optoelectronic devices in THz range, security systems
IPhChE, GPI RAS, LPI RAS, MIREA, Research Institute "Polyus", University of Oxford (UK), University of Southern California (USA)
Nanoelectronics, electronics based on new principles and materials, functional systems engineering
Education. Modern disciplines:
Terahertz nanophotonics: research and development of the modern optoelectronic devices in THz range, security systems
Education. Modern disciplines:
Direction of training/level
Name of program
Speciality's/Bachelor's degree program
14.05.04- Electronics and automation of physical plants
Electronic devices and systems
Bachelor's degree program
14.03.02-Nuclear Physics and Technology
Condensed matter physics
Applied Molecular Physics*
Physical and technical problems of metrology*
Physics of fast processes
Bachelor's degree program
01.03.02-Applied Mathematics and Informatics
Mathematical modeling in condensed matter physics
Bachelor's degree program
The physics of kinetic phenomena
Master's degree program
14.04.02-Nuclear Physics and Technology
Physical and technical problems of metrology
Physics of fast processes
Applied Physics and Ion Mass Spectrometry
Physics and Nanotechnology of heterostructure electronics*
Master's degree program
01.04.02-Applied Mathematics and Informatics
Mathematical modeling in condensed matter physics*
Master's degree program
The physics of kinetic phenomena*
Postgraduate's degree program
03.04.02-Physics and Astronomy
6.11.01-Electronics,radio engineering and communication systems
Condensed matter physics*
Solid-state electronics, radio-electronic components, micro-and nanoelectronics, devices based on quantum effects
*Programs marked with a sign (*) are implemented in English
Leading foreign scientists:
Z.Insepov (USA) - professor of Purdue University, professor of MEPhI, H-index=21
J.J.H.Brower (Netherlands) - professor, H-index=50
V.A.Labunov (Belarus) - professor, H-index=15
Leading scientists of NESPI
A.A.Bagatur'yants - professor of MEPhI, H-index=17
V.V.Volkov - professor of MEPhI, H-index=30
S.A.Nikitov - professor of MEPhI, corresponding member of RAS, H-index=17
V.M.Samsonov - professor of MEPhI, H-index=68
V.A.Kulbachinskii - professor of MEPhI, MSU, H-index=16
S.B.Dabagov - professor of MEPhI, H-index=15
V.F.Elesin - professor of MEPhI, H-index=16
We present the first measurement of charge-dependent directed flow in Cu+Au collisions at sNN=200 GeV. The results are presented as a function of the particle transverse momentum and pseudorapidity for different centralities. A finite difference between the directed flow of positive and negative charged particles is observed that qualitatively agrees with the expectations from the effects of the initial strong electric field between two colliding ions with different nuclear charges. The measured difference in directed flow is much smaller than that obtained from the parton-hadron-string-dynamics model, which suggests that most of the electric charges, i.e., quarks and antiquarks, have not yet been created during the lifetime of the strong electric field, which is of the order of, or less than, 1 fm/c. © 2017 American Physical Society.
Results on two-particle Δ ηΔ ϕ correlations in inelastic p + p interactions at 20, 31, 40, 80, and 158 GeV/c are presented. The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The data show structures which can be attributed mainly to effects of resonance decays, momentum conservation, and quantum statistics. The results are compared with the Epos and UrQMD models. © 2017, The Author(s).
A series of (dibenzoylmethanato)boron difluoride (BF2DBM) derivatives with a halogen atom in one of the phenyl rings at the para-position were synthesized and used to elucidate the effects of changing the attached halogen atom on the photophysical properties of BF2DBM. The room-temperature absorption and fluorescence maxima of fluoro-, chloro-, bromo- and iodo-substituted derivatives of BF2DBM in THF are red-shifted by about 2–10 nm relative to the corresponding peaks of the parent BF2DBM. The fluorescence quantum yields of the halogenated BF2DBMs (except the iodinated derivative) are larger than that of the unsubstituted BF2DBM. All the synthesized compounds are able to form fluorescent exciplexes with benzene and toluene (emission maxima at λem = 433 and 445 nm, respectively). The conformational structure and electronic spectral properties of halogenated BF2DBMs have been modeled by DFT/TDDFT calculations at the PBE0/SVP level of theory. The structure and fluorescence spectra of exciplexes were calculated using the CIS method with empirical dispersion correction. © 2016 Elsevier B.V.
BiFeO3 perovskite attracts great attention due to its multiferroic properties and potential use as a parent material for Bi1-xSrxFeO3-δ and Bi1-xSrxFe1-yCoyO3-δ solid solutions in intermediate temperature cathodes of oxide fuel cells. Another iron-based LaFeO3 perovskite is the end member for well-known solid solutions (La1-xSrxFe1-yCoyO3-δ) used for oxide fuel cells and other electrochemical devices. In this study an ab initio hybrid functional approach was used for the study of the thermodynamic stability of both LaFeO3 and BiFeO3 with respect to decompositions to binary oxides and to elements, as a function of temperature and oxygen pressure. The localized (LCAO) basis sets describing the crystalline electron wave functions were carefully re-optimized within the CRYSTAL09 computer code. The results obtained by considering Fe as an all-electron atom and within the effective core potential technique are compared in detail. Based on our calculations, the phase diagrams were constructed allowing us to predict the stability region of stoichiometric materials in terms of atomic chemical potentials. This permits determining the environmental conditions for the existence of stable BiFeO3 and LaFeO3. These conditions were presented as contour maps of oxygen atoms' chemical potential as a function of temperature and partial pressure of oxygen gas. A similar analysis was also performed using the experimental Gibbs energies of formation. The obtained phase diagrams and contour maps are compared with the calculated ones. © the Owner Societies 2017.
The inclusive J/ψ production has been studied in Pb–Pb and pp collisions at the centre-of-mass energy per nucleon pair sNN=5.02 TeV, using the ALICE detector at the CERN LHC. The J/ψ meson is reconstructed, in the centre-of-mass rapidity interval 2.5 and in the transverse-momentum range 12 GeV/c, via its decay to a muon pair. In this Letter, we present results on the inclusive J/ψ cross section in pp collisions at s=5.02 TeV and on the nuclear modification factor RAA. The latter is presented as a function of the centrality of the collision and, for central collisions, as a function of the transverse momentum pT of the J/ψ. The measured RAA values indicate a suppression of the J/ψ in nuclear collisions and are then compared to our previous results obtained in Pb–Pb collisions at sNN=2.76 TeV. The ratio of the RAA values at the two energies is also computed and compared to calculations of statistical and dynamical models. The numerical value of the ratio for central events (0–10% centrality) is 1.17±0.04(stat)±0.20(syst). In central events, as a function of pT, a slight increase of RAA with collision energy is visible in the region 2 GeV/c. Theoretical calculations qualitatively describe the measurements, within uncertainties. © 2017 The Author
We report the test of many of the key elements of the laser-based calibration system for muon g - 2 experiment E989 at Fermilab. The test was performed at the Laboratori Nazionali di Frascati's Beam Test Facility using a 450 MeV electron beam impinging on a small subset of the final g - 2 lead-fluoride crystal calorimeter system. The calibration system was configured as planned for the E989 experiment and uses the same type of laser and most of the final optical elements. We show results regarding the calorimeter's response calibration, the maximum equivalent electron energy which can be provided by the laser and the stability of the calibration system components.
It is shown that an island metal film could be characterized by nonlocal effective dielectric permeability described by simple algebraic equations, derived within the frame of this project. Based on this concept, elastic and inelastic light scattering was calculated in the vicinity to the dipole surface plasmon frequency on an isolated particle. In addition, the effective absorption due to the light localization in the island film consisting of nonabsorbing particles was explained. © 2016 Elsevier B.V.
The steady-state and time-resolved linear spectral properties, two-photon absorption spectra and fast relaxation processes in the excited states of styryl base-type derivatives were investigated. The nature of linear absorption, fluorescence and excitation anisotropy spectra were analyzed in solvents of different polarity at room temperature and specific dependence of the solvatochromic behavior on the donor-acceptor strength of the terminal substituents was shown. Two-photon absorption (2PA) efficiency of styryl dye bases was determined in a broad spectral range using two-photon induced fluorescence technique, and cross-sections maxima of ~ 100 GM were found. The excited state absorption (ESA) and fast relaxation processes in the molecular structures were investigated by transient absorption femtosecond pump-probe methodology. The role of twisted intramolecular charge transfer (TICT) effect in the excited state of styryl dye base with dimethylamino substituent was shown. The experimental spectroscopic data were also verified by quantum chemical calculations at the Time Dependent Density Functional Theory level, combined with a polarizable continuum model. © 2016 Elsevier B.V.
Prospects of using metal-hole arrays for the enhanced optical detection of molecular chirality in nanosized volumes are investigated. Light transmission through the holes filled with an optically active material is modeled, and the activity enhancement by more than an order of magnitude is demonstrated. The spatial resolution of the chirality detection is shown to be of a few tens of nanometers. From comparing the effect in arrays of cylindrical holes and holes of complex chiral shape, it is concluded that the detection sensitivity is determined by the plasmonic near-field enhancement. The intrinsic chirality of the arrays due to their shape appears to be less important. © 2017 Optical Society of America.
The electron irradiation effect on hydrogen sensors based on metal-insulator-semiconductor transistor (MISFET) with structure Pd-Ta2O5-SiO2-Si was experimentally investigated. The MISFET threshold voltage as a function of hydrogen concentration was determined before and after each irradiation. Represented threshold voltage models of hydrogen and radiation sensitivities were used to interpret the experimental data, to estimate the critical doses and to forecast the performance characteristics of the hydrogen sensors based on MISFET under action of ionizing radiation. © 2016 Elsevier B.V.
The novel method of modification of hollow fiber membranes from polysulfone is proposed. The method involves the use of aqueous solutions of polyvinylpyrrolidone (PVP) as a bore fluid in the dry-jet wet spinning process. Increasing PVP concentration (1–5 wt%) in the bore fluid was found to yield in the efficient hydrophilization of the inner skin layer of the hollow fiber membrane. The contact angle of the skin layer was found to decrease from 76° down to 54° when the PVP concentration in the bore fluid is 1 wt% and down to 45° – at 5 wt%. The FTIR-spectra studies reveal the presence of PVP only on the inner surface of the modified hollow fiber membrane while outer surface was found to represent unmodified polysulfone. Scanning electron microscopy and atomic force microscopy studies reveal a difference in the structure of the initial and modified membranes. Introduction of PVP into the bore fluid leads to the marked changes in membrane pure water permeability and rejection. When the bore fluid contains 5 wt% of PVP, the rejection coefficient for PVP (Mn=40 000 g mol−1) was found to increase from 29% to 85%, and the pure water flux – to decrease from 370 to 130 L m−2 h−1 bar−1 compared with the initial membrane. Antifouling characteristics against human serum albumin are shown to be significantly improved for the modified hollow fiber membranes compared with the initial membranes. © 2016 Elsevier B.V.
We theoretically study macroscopic dielectric properties of hyperbolic metamaterials proceeding from microscopic description. The theory constructed gives the answer to the question “what properties should microscopic elements have in order to macroscopic system consisting of these elements would be a hyperbolic metamaterial.” Generalized Clausius–Mossotti relation as well as existing conditions for such metamaterials is obtained with help of the local field theory. The perpendicular and parallel components of the dielectric permittivity are found as functions of microscopic parameters of a single particle and a dielectric matrix. © 2016, Springer-Verlag Berlin Heidelberg.
The paper proposes a device that allows to remotely carrying out daily monitoring of the patient’s blood pressure. The device is autonomous, uses oscillometric pressure measurement method with a stepwise pressure releasing and saving records of the pressure in the cuff. The authors describes the method of determining the blood pressure and the heart rate, as well as the data analysis algorithm, which was received by a device for daily monitoring of the blood pressure © 2017 by Ceser Publications.
A simple analytical model of the field-diffusion coefficient is developed for moderate carrier concentrations. Hopping transport is described by the multiple-trapping model based on the transport-level concept. A continuity equation with a diffusion coefficient depending on carrier concentration is obtained, the time dependence of the field-diffusion coefficient under non-steady-state conditions is found. The time intervals in which deep state population affects the mobility and diffusion coefficient under conditions of time-of-flight experiments are estimated. It is shown that the field-diffusion coefficient increases in a long time interval while the mobility is unchanged, which is reminiscent of a similar case of nonequilibrium initial carrier generation at the low-concentration limit. © 2017, Pleiades Publishing, Ltd.
The initial stage of hydrogen desorption from fully hydrogenated carbon nanotubes (3.0) and (2.2) is numerically studied by the molecular dynamics method. The temperature dependence of the desorption rate is directly determined at T = 1800–2500 K. The characteristic desorption times are determined at temperatures outside this range by extrapolation. It is shown that hydrogen desorption leads to the appearance of electronic states in the band gap. © 2017, Pleiades Publishing, Ltd.
In our work, we investigate magnetic properties of metamaterial–metal interface with the help of the local field theory combined with the method of images. Proceeding from microscopic description of the substance and calculating its macroscopic properties, for the first time the modified Clausius–Mossotti relation has been obtained for permeability of the metamaterial bordering a metal. © 2016, Springer-Verlag Berlin Heidelberg.
The effectiveness of the software aimed at automated recognition of the pathologies and morphological changes of the digestive tract by the images obtained by the wireless endoscopic capsule depends on the pictures’ quality. This article deals with the algorithm for recovering the loss of the data from the part of the image code that encodes the picture itself, not the loss of metadata (supplementary information at the beginning of the entire code). The algorithm allows to reconstruct the images with shifted blocks by returning them to their original place and restoring their original colour. The algorithm was tested on 159 damaged images with different number of the breakdown and the experiment has restored about 90% of distorted frames. © 2017 [International Journal of Imaging and Robotics].
A method and experimental setup for measuring the permeability of membrane and film materials has been developed. This method is based on determining the kinetics of the pressure change in a liquid above a membrane. The permeability of solvents through a glassy polymer is studied over wide ranges of temperature and pressure. This method and the associated apparatus can be used to determine the permeability of solvents through membrane materials with high accuracy for both convective and diffusive liquid transport. © 2017 Springer Science+Business Media New York
The γ-ray data of Fermi-LAT on the giant lobes of Centaurus A are analysed together with the high frequency radio data obtained with the Planck satellite. The large γ-ray photon statistics, accumulated during seven years of observations, and the recently updated Fermi-LAT collaboration software tools allow substantial extension of the detected γ-ray emission towards higher energy, up to 30 GeV, and lower energy, down to 60 MeV. Moreover, the new γ-ray data allow us to explore the spatial features of γ-ray emission of the lobes. For the north lobe, we confirm, with higher statistical significance, our earlier finding on the extension of γ-ray emission beyond the radio image. Moreover, the new analysis reveals significant spatial variation of γ-ray spectra from both lobes. On the other hand, the Planck observations at microwave frequencies contain important information on spectra of synchrotron emission in the cutoff region, and thus allow model-independent derivation of the strength of the magnetic field and the distribution of relativistic electrons based on the combined γ-ray and radio data. The interpretation of multiwavelength spectral energy distributions (SEDs) of the lobes within a pure leptonic model requires strong enhancement of the magnetic field at the edge of the south lobe. Alternatively, a more complex, leptonic-hadronic model of the gamma-ray emission, postulating a non-negligible contribution of the π0-decay component at highest energies, can explain the γ-ray data with a rather homogeneous distribution of the magnetic field over the giant lobes. © 2017 Author(s).
The education technology with continuous monitoring of the current functional and emotional students' states is suggested. The application of this technology allows one to increase the effectiveness of practice through informed planning of the training load. For monitoring the current functional and emotional students' states non-contact remote technologies of person bioparameters registration are encouraged to use. These technologies are based on recording and processing in real time the main person bioparameters in a purely passive mode. Experimental testing of this technology has confirmed its effectiveness. © 2017, American Institute of Physics Inc. All rights reserved.
Recently the MAGIC collaboration reported about the extension of the pulsed gamma-ray emission from the Crab pulsar beyond 1 TeV. Despite the consensus between different theoretical models regarding the production mechanism of the pulsed VHE gamma-rays (the inverse Compton scattering of electrons), the origin of ultrarelativistic electrons and the location of the gamma-ray production region remain two key but highly uncertain issues. We discuss a possible scenario of production of the pulsed gamma-ray emission under the assumption that the acceleration of electrons takes place at the light cylinder and calculate the energy spectrum of high-energy radiation caused by the inverse Compton scattering in two target photon fields originating from the heated surface of the neutron star (thermal photons) and from the magnetosphere itself (nonthermal photons). The total rate of acceleration of relativistic electrons required to explain the observed flux of gamma-rays can be as small as 1 percent of the spin-down luminosity of the Crab pulsar. We argue that the magnetocentrifugal acceleration of plasma at the light cylinder is responsible for these electrons. © 2017 Author(s).
Motivation has a major impact on the results of a child's learning at school and a student's learning at the University. Moreover, school education creates a foundation for the study at the university, which is used by a student for in-depth and rapid development of specialized disciplines, reaching the level of independent research and development. The modern system of teaching physics at school is built in such a way that, basically, a teacher is demonstrating and a child is looking. Such a system, in addition to the logical lack of practical skills, leads to a significant reduction in the motivation for further engineering study, which is now a priority for Russia. There are original methods of practical teaching for students starting from the 5th grade, which allow each student to try to assemble on their own a variety of devices, reaching quick practical results. The principles of this technique are discussed in the article. Prototyping boards without solder were chosen as the basic platform to showcase the methodology. © 2017, American Institute of Physics Inc. All rights reserved.
It is generally believed that the radiation of relativistic particles in a curved magnetic field proceeds in either the synchrotron or the curvature radiation modes. We study an intermediate, the so-called synchro-curvature regime. Using the Hamiltonian formalism, we find the trajectory of relativistic particle in the curved magnetic field that has the form of a helix wound around the drift trajectory. We show that the transition to the limit of the synchrotron and curvature radiation regimes is determined by relation between curvatures of the drift trajectory and gyration motion around it. When both are approximately equal, the curvature of the trajectory start to noticeably oscillate with the frequency of particle gyration leading to the synchro-curvature radiation with averaged spectrum different from synchrotron or curvature one. The performed numerical calculations with energy losses and different initial pitch angles confirm the principal conclusions based on the simplified analytical treatment. © 2017 Author(s).
The considered method of learning the basics of microelectronic circuits and systems amplifier enables one to understand electrical processes deeper, to understand the relationship between static and dynamic characteristics and, finally, bring the learning process to the cognitive process. The scheme of problem-based learning can be represented by the following sequence of procedures: the contradiction is perceived and revealed; the cognitive motivation is provided by creating a problematic situation (the mental state of the student), moving the desire to solve the problem, to raise the question "why?", the hypothesis is made; searches for solutions are implemented; the answer is looked for. Due to the complexity of architectural schemes in the work the modern methods of computer analysis and synthesis are considered in the work. Examples of engineering by students in the framework of students' scientific and research work of analog circuits with improved performance based on standard software and software developed at the Department of Microelectronics MEPhI. © 2017, American Institute of Physics Inc. All rights reserved.
The existing psychological theories associate the movement of a human eye with its reactions to external change: what we see, hear and feel. By analyzing the glance, we can compare the external human response (which shows the behavior of a person), and the natural reaction (that they actually feels). This article describes the complex for detection of visual activity and its application for evaluation of the psycho-physiological state of a person. The glasses with a camera capture all the movements of the human eye in real time. The data recorded by the camera are transmitted to the computer for processing implemented with the help of the software developed by the authors. The result is given in an informative and an understandable report, which can be used for further analysis. The complex shows a high efficiency and stable operation and can be used both, for the pedagogic personnel recruitment and for testing students during the educational process. © 2017, American Institute of Physics Inc. All rights reserved.
This studies deal with the description and systematization of the popular patent retrieval resources. The importance of the non-patent information when conducting patent research for the intellectual property created in educational and scientific activity of the university is highlighted. The differences in the patent and non-patent information are found out. Based on the databases' analysis the authors conducted the patent research on "Wireless endoscopic capsules" (development of the NRNU MEPhI). This study can be used to facilitate the university work on the new product development in order to improve the efficiency of the process of the commercialization of the intellectual activity results, including the entering the international market. © 2017, American Institute of Physics Inc. All rights reserved.
An all-digital phase locked loop (ADPLL) was implemented in 180 nm CMOS technology. The proposed ADPLL uses a digitally controlled oscillator to achieve 3 ps resolution. The pure digital phase locked loop is attractive because it is less sensitive to noise and operating conditions than its analog counterpart. The proposed ADPLL can be easily applied to different process as a soft IP block, making it very suitable for system-on-chip applications.
The paper describes a preamplifier, elaborated to process the signals of silicon X-ray drift detectors. The preamplifier has been designed in CMOS 0.35 um technology and optimized for operation with detectors, having capacitances of 100 fF. The feedback capacitance of 10 fF provides a gain of 100 mV/fC, ENC at T = -30°C equals 4 e (simulation result) at using shaper of the 6supth/sup order with a time constant of 8 us. Power consumption is 1.3 mW (preamplifier and shaper). © 2016 IOP Publishing Ltd and Sissa Medialab srl.
For many years effective detection of hazardous substances such as nitrogen oxides has remained a crucial task for environmental safety. In this article, we demonstrate high promising NO2-sensitive Langmuir-Blodgett monolayer structures based on 2-((2'- hydroxymethyl)-benzyloxy)-9(10),16(17),23(24)-tri-/re/-butyl- substituted low symmetrical zinc phthalocyanine complex bearing hydroxyl group on the periphery (compound 1). Amphiphilic arrangement of macrocycles was demonstrated to eliminate disordered molecular aggregation, resulting in a marked NO2 gas sensing effect under real atmospheric conditions. The optical response of monolayers was at room temperature, with the significant spectral changes being caused by the specific charge transfer process in phthalocyanine n-conjugated electronic system. © Published under licence by IOP Publishing Ltd.
This study is devoted to the development of a method for the registration of multiple-cell upsets (MCUs) in memory cells induced by single nuclear particles. The presented results illustrate the possibility of finding MCUs in high capacity (higher than 1 Mbit) memory cells using the improved method. © 2016, Pleiades Publishing, Ltd.
We demonstrate a new way for detection ultralow concentration of explosives in this study. It combines an ion mobility spectrometry (IMS) and a promising method of laser desorption/ionization on silicon (DIOS). The DIOS is widely used in mass spectrometry due to the possibility of small molecule detection and high sensitivity. It is known that IMS based on laser ion source is a power method for the fast detection of ultralow concentration of organic molecules. However requirement of using high energy pulse ultraviolet laser increases weight and size of the device. The use of DIOS in an ion source of IMS could decrease energy pulse requirements and allows one to construct both compact and high sensitive device for analyzing gas and liquid probes. On the other hand mechanisms of DIOS in gas media is poorly studied, especially in case of nitroaromatic compounds. The investigation of the desorption/ionization on porous silicon (pSi) surface of nitroaromatic compounds has been carried out for 2,4,6-trinitrotoluene (TNT) using IMS and mass spectrometry (MS). It has been demonstrated that TNT ion formation in a gas medium is a complicated process and includes both an electron emission from the pSi surface with subsequent ion-molecular reactions in a gas phase and a proton transfer between pSi surface and TNT molecule. © 2016 SPIE.
It is shown that the acoustic scaling patterns of anisotropic flow for different event shapes at a fixed collision centrality (shape-engineered events), provide robust constraints for the event-by-event fluctuations in the initial-state density distribution from ultrarelativistic heavy ion collisions. The empirical scaling parameters also provide a dual-path method for extracting the specific shear viscosity of the quark-gluon plasma (QGP) produced in these collisions. A calibration of these scaling parameters via detailed viscous hydrodynamical model calculations, gives estimates for the plasma produced in collisions of Au + Au () and Pb + Pb (). The estimates are insensitive to the initial-state geometry models considered. © 2016 IOP Publishing Ltd.
The article considers modernized CMOS SOI test structure measurement system that allows one to control characteristics of both separate transistors and VLSI blocks during experiment. Changes made in hardware and software parts of the measurement setup are discussed and reasoned. © 2016 IEEE.
A mass-spectrometric study of photo processes initiated by ultraviolet (UV) laser radiation in explosives adsorbed on metal and dielectric substrates has been performed. A calibrated quadrupole mass spectrometer was used to determine a value of activation energy of desorption and a quantity of explosives desorbed by laser radiation. A special vacuumoptical module was elaborated and integrated into a vacuum mass-spectrometric system to focus the laser beam on a sample. It has been shown that the action of nanosecond laser radiation set at q= 107 - 108 W/cm2, λ=266 nm on adsorbed layers of molecules of trinitrotoluene (TNT) and pentaerytritoltetranitrate (PETN) leads not only to an effective desorption, but also to the non-equilibrium dissociation of molecules with the formation of nitrogen oxide NO. The cyclotrimethylenetrinitramine (RDX) dissociation products are observed only at high laser intensities (q> 109 W/cm2) thus indicating the thermal nature of dissociation, whereas desorption of RDX is observed even at q> 107 W/cm2 from all substrates. Desorption is not observed for cyclotetramethylenetetranitramine (HMX) under single pulse action: the dissociation products NO and NO2 are registered only, whereas irradiation at 10Hz is quite effective for HMX desorption. The results clearly demonstrate a high efficiency of nanosecond laser radiation with λ = 266 nm, q ∼ 107 - 108 W/cm2, Epulse= 1mJ for desorption of molecules of explosives from various surfaces. © 2016 SPIE.
Comparison of desorption effectiveness of two laser sources: continuous diode laser (λ = 440 nm, P = 0.5 W) and laser based on YAG: Nd3+ (X = 266 nm, τ pulse = 6 ns, Epulse = 1.0 mJ, f = 10 Hz, Ipulse = 108 W/cm2) was carried out for the explosive cyclotrimethylenetrinitramine (RDX). The results of mass spectrometric studies of RDX laser desorption from a quartz substrate are discussed. It is shown that a continuous diode laser (λ = 440 nm) effectively desorbs the analyte without accompanying dissociation. The typical desorbed mass is 70 ng for RDX at 1.1 minutes exposure. However a laser based on YAG: Nd3+ seems to be more efficient for the same time exposure. © Published under licence by IOP Publishing Ltd.
The results of an experimental study of the effect of acoustic interference and noise on the reaction time of a person are presented. The analytical dependence, allowing the evaluation the impact of objective and subjective factors on the reaction time is proposed. The total power of acoustic noises, acoustic noises character, reverberation time within working place are considered as the objective factors.
The possibility of emergency situations, caused by the human factor, prediction process automatization is discussed. The perspectives of a new terahertz technology practical application for remote non-contact person bio-parameters check are analyzed. The aim of such technology practical implementation is continuous monitoring of his current psycho-emotional and functional state. The terahertz and classical optical and infrared technologies comparison results are presented. The terahertz technology possibility and feasibility applying aspects for different types of emotional testing in various areas of the economy are discussed.
The paper analyzes methodological aspects of automatized prediction of emergency situation of technogenic origin determined by the human factor, paying special attention to distance no-contact technologies of continuous monitoring of the current functional and emotional state of the operators and discussing ways of developing models describing functioning of a working shift, team or crew, as well as individuals.
The paper discusses an analytical model of plasma-chemical etching in planar diode- type reactor. Analytical expressions of etch rate and etch anisotropy were obtained. It is shown that etch anisotropy increases with increasing the ion current and ion energy. At the same time, etch selectivity of processed material decreases as compared with the mask. Etch rate decreases with the distance from the centre axis of the reactor. To decrease the loading effect, it is necessary to reduce the wafer temperature and pressure in the reactor, as well as increase the gas flow rate through the reactor.
We obtain from the first principles a generalized Clausius-Mossotti relation describing the dielectric permittivity of a semi-infinite artificial periodic structure. The obtained expressions include the spatial dispersion and permit defining resonant conditions for propagating waves.
A technique for obtaining gas sensor samples from graphite paper with a nanotube film is described. Current-induced annealing of the graphite paper and additional evaporation of a nanotube graphite film in a hydrogen atmosphere are combined in the developed technique. The current−voltage characteristics of the samples have been measured at room temperature in air, in vacuum, and at low concentrations of NH3, ethanol, and acetone. Experiments demonstrate that these samples containing carbon multiwall nanotubes can be used as a gas sensor to detect the presence of NH3 and acetone. They are characterized by high sensitivity and selectivity, fast response, restoration, and stability of the characteristics. The estimated sensor sensitivities to NH3, acetone, and ethanol at a current of 96.8 mA are ~15, ~12, and ~1 mV/Torr, respectively. Their sensitivity is determined by the difference in the behavior of their current−voltage characteristics under exposure to NH3, ethanol, and acetone. The sensor features fast response (5–20 s) and restoration (within 5 min, restoration to the initial state before the exposure to NH3 is 100.2%), as well as the stability of its characteristics (the pressure ranges from 1 × 10sup–6/sup to 760 Torr). © 2016, Pleiades Publishing, Inc.
The results of a voltage-current characteristics study of sensors made of graphite paper with multiwall nanotubes are presented. It has been found experimentally that these samples are usable as gas sensors for the detection of NH3, H2, and Cl2 in air. © 2016 Springer Science+Business Media New York
Semiconductor quantum dots (QDs) obtained by means of colloidal synthesis are widely used in fabrication of organic light-emitting devices (OLEDs). We have fabricated QD-OLEDs with an active light-emitting layer formed by novel CdSe/ZnS/CdS/ZnS core-multishell QDs that have luminescence quantum yield of more than 90%. We have compared the performance of QD-OLEDs with different thickness of the active layer and demonstrated that the best performance is achieved at 45-55 nm, probably due to field redistribution inside the device. Optimization of the thicknesses of transport layers of QD-OLED is likely to further improve the performance of such devices. (C) 2016 Elsevier Ltd. All rights reserved.
A satellite with the NUCLEON apparatus was launched in Dec. 2014. The space NUCLEON project of ROSCOSMOS is designed to investigate cosmic ray nuclei energy spectra from 100 GeV to 1000 TeV as well as cosmic ray electron spectra from 20 GeV to 3 TeV. The method of energy determination by means of a silicon instrument for measuring the particle charge of cosmic rays and the calorimetric system were developed. The main parameters, that determine the quality of calorimetric systems are linearity of transfer characteristic and the dynamic range of input signals, which should reach 30 000 MIPs ( minimum ionizing particles). The ASIC, satisfying these requirements, consisting of 32 channels with a unique dynamic range from 1 to 40000 MIPs, signal to noise ratio not less than 2.5 at a shaper peaking time of 2 mu s and a low power consumption of 1.5 mW/channel has been designed. The first results of the ASIC functionality in space are presented.
The paper discusses the automation of the processing of images obtained with an oscilloscope using National Instruments LabVIEW software. The mathematical background is presented as well as standard hardware communication interface. The block diagram of the electrical signal acquisition and processing system and the front panel with an example of processed waveforms is shown in the paper. © The Authors, published by EDP Sciences, 2016.
Recently it was shown that charged particles motion in the field of standing electromagnetic wave can undergo the features similar to the particles channeling in crystals. When a charged particle enters the channels formed by electromagnetic standing waves at a small angle to the node (anti-node) planes its motion represents namely the oscillations between two neighboring planes. The phenomenon is mostly known as channeling in a lattice of the standing waves. Obviously, this effect can be used to handle beams in accelerator physics, more general, for the beam shaping with the specific properties. The advantage of the plane wave channeling is the absence of inelastic scattering that takes place in a crystal. The possibility to re-distribute the current density of particles in the beam by means of the laser standing wave is demonstrated. © Published under licence by IOP Publishing Ltd.
Experimental equipment for extraction of ELDRS conversion model parameters was described. The equipment involves measure device with three voltage sources, three current sensors, one voltmeter and two relay switchboards. All the components of the device are controlled by computer program, which enable to provide measurements during irradiation in automatic mode. The program is able to perform math processing of experimental results to obtain conversion model parameters. The availability of the equipment for experimental extraction of the parameters was demonstrated for voltage comparator LM 111. The estimation of the dependence of input current of the comparator on total dose at low dose rate and elevated temperature was presented and experimentally verified. © Springer Science+Business Media Singapore 2016.
The processes of laser-assisted synthesis of Tritium nuclei and their laser-induced decay in cold plasma in the vicinity of solid targets (Au, Ti, Se, etc.) immersed into heavy water are experimentally realized at peak laser intensity of 10sup10/sup-10sup13/sup W/cmsup2/sup. Initial stages of Tritium synthesis and their laser-induced beta-decay are interpreted on the basis of non-elastic interaction of plasma electrons having kinetic energy of 5-10 eV with nuclei of Deuterium and Tritium, respectively. © Published under licence by IOP Publishing Ltd.
©, where φ1-φ2 is the angular difference in azimuth, is studied as a function of the pseudorapidity difference between particle pairs Δη=η1-η2. Nonzero v322 is directly related to the previously observed large-Δη narrow-Δφ ridge correlations and has been shown in models to be sensitive to the existence of a low viscosity quark gluon plasma phase. For sufficiently central collisions, v322 persist down to an energy of 7.7 GeV, suggesting that quark gluon plasma may be created even in these low energy collisions. In peripheral collisions at these low energies, however, v322 is consistent with zero. When scaled by the pseudorapidity density of charged-particle multiplicity per participating nucleon pair, v322 for central collisions shows a minimum near sNN=20 GeV.
Balance functions have been measured in terms of relative pseudorapidity (Δη) for charged particle pairs at the BNL Relativistic Heavy Ion Collider from Au + Au collisions at sNN=7.7GeV to 200 GeV using the STAR detector. These results are compared with balance functions measured at the CERN Large Hadron Collider from Pb + Pb collisions at sNN=2.76TeV by the ALICE Collaboration. The width of the balance function decreases as the collisions become more central and as the beam energy is increased. In contrast, the widths of the balance functions calculated using shuffled events show little dependence on centrality or beam energy and are larger than the observed widths. Balance function widths calculated using events generated by UrQMD are wider than the measured widths in central collisions and show little centrality dependence. The measured widths of the balance functions in central collisions are consistent with the delayed hadronization of a deconfined quark gluon plasma (QGP). The narrowing of the balance function in central collisions at sNN=7.7 GeV implies that a QGP is still being created at this relatively low energy. © 2016 American Physical Society.
Recent progress with wake-field acceleration has shown a great potential in providing high gradient acceleration fields, while the quality of the beams remains relatively poor. Precise knowledge of the beam size at the exit from the plasma and matching conditions for the externally injected beams are the key for improvement of beam quality. Betatron radiation emitted by the beam during acceleration in the plasma is a powerful tool for the transverse beam size measurement, being also non-intercepting. In this work we report on the technical solutions chosen at SPARC_LAB for such diagnostics tool, along with expected parameters of betatron radiation. © 2016 Elsevier B.V.
Multiplicity, rapidity and transverse momentum distributions of hadrons produced both in inelastic and nondiffractive pp collisions at energies from root s = 200 GeV to 14 TeV are studied within the Monte Carlo quark-gluon string model. Good agreement with the available experimental data up to root s = 13 TeV is obtained, and predictions are made for the collisions at top LHC energy root s = 14 TeV. The model indicates that Feynman scaling and extended longitudinal scaling remain valid in the fragmentation regions, whereas strong violation of Feynman scaling is observed at midrapidity. The Koba-Nielsen-Olesen (KNO) scaling in multiplicity distributions is violated at LHC also. The origin of both maintenance and violation of the scaling trends is traced to short range correlations of particles in the strings and interplay between the multistring processes at ultrarelativistic energies.
We present an Application Specific Integrated Circuit (ASIC), which is intended for readout and analog processing of silicon photomultiplier (SiPM) arrays' signals. The number of channels of the analog front-end ASIC as well as the types of their input stages depends on the application. The current version of the chip contains three current-input channels and three voltage-input channels. Each of the channels includes a programmable pre-amplifier, integrator with baseline holder, code-controlled amplifiers, amplitude discriminator, two programmable timers, low pass filter, peak detector, and output buffer with the baseline tuning circuitry. The device uses a serial interface for programming its configuration and parameters. It is implemented in 0.35μm CMOS technology. © 2016 IEEE.
The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to δU = 12.7 (V/700 m/s)2(300 K/T)(L/1 m) kg·SWU/yr, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges. © 2016.
A critical revision of the essential principles of the physics of relativistic flows of cold plasma is given. We prove that the approximation of ideal magnetic hydrodynamics of the cold plasma is equivalent to the drift approximation of motion of charged particles in an electromagnetic field. The equations of magnetohydrodynamics are obtained from equations for the drift motion of the charged particles. The conditions of application of the equations of ideal magnetohydrodynamics are obtained. In the case of the Crab pulsar the violation of the frozen-in condition can happen at a distance that well exceeds the distance to the termination shock. One fluid MHD can be incorrect at the light cylinder provided that the Lorentz factor of the plasma exceeds 10sup4/sup and the curvature radius of the flow line is comparable with the light cylinder. It is shown that the electric currents in the cold plasma are the result of the inertial drift motion of the charged particles in the crossed electric and magnetic fields. © 2016 Cambridge University Press.
Impact of the pulsed braking force on the axial gas circulation in centrifuges for a uranium isotope separation was investigated by the method of numerical simulation. Two camera model has been explored. The pulsed braking of the rotating gas results into generation of waves which propagate along all length of the rotor of the centrifuge. The wavelength appears in accordance with predictions of our analytic theory. Pulsations almost doubles the axial circulation flux in the working camera in comparison with the case of the steady state breaking force with the same average power. © 2015 Elsevier Inc. All rights reserved.
2D axisymmetric transient flow induced by a pulsed braking force in the Iguasu gas centrifuge is simulated numerically. The simulation is performed for two cases: transient and stationary. The braking forces averaged over the period of rotation are equal to each other in both cases. The transient case is compared with the stationary case where the flow is excited by the stationary braking force. In the transient case the gas flux through the gap in the bottom baffle exceeds on 15 % the same flux in the stationary case for the same gas content and temperature at the walls of the rotor. We argue that the waves can reduce the gas content in the GC on the same 15 %. © 2016 Author(s).
Impact of the pulsed braking force on the axial gas circulation and gas content in centrifuges for uranium isotope separation was investigated by the method of numerical simulation. Pulsed brake of the rotating gas by the momentum source results into generation of the waves which propagate along the rotor of the centrifuge. The waves almost doubles the axial circulation flux in the working camera in compare with the case of the steady state breaking force with the same average power in the model under the consideration. Flux through the hole in the bottom baffle on 15% exceeds the flux in the stationary case for the same pressure and temperature in the model. We argue that the waves reduce the pressure in the GC on the same 15%. © Published under licence by IOP Publishing Ltd.
A method for designing adaptive systems for automatic extremum search to stabilize the power factor of local electric power system of electric is considered. It consists in application of the serially connected capacitors compensating the reactive component of the total electric power of in parallel connected centrifugal machines usually called as an aggregate. Operation of the system just demands measuring voltage at the output of the static frequency converter for electric drives. The proposed control system is designed to stabilize the power factor close to unity in a case of alteration of parameters of a separation cascade or a single separation device in an aggregate. Such system can be operated continuously or connected occasionally depending on a technological situation. In addition, it totally excludes the phenomenon of overcompensation. © Published under licence by IOP Publishing Ltd.
Magnetron sputtering is the well-known and widely-used deposition technique for coating versatile high-quality and well-adhered films. However, the technology has some limitations, caused by high temperatures on the coating surface. The paper is devoted to the experimental development of a process of magnetron sputtering of copper on a surface coated with a thermosensitive polymer made of carbon fiber with epoxide binder. This process is applied for balancing a rotor of a gas centrifuge for isotope separation. The optimum operating parameters of the process are found and discussed. They were in quantitative agreement with data obtained by means of non-stationary modeling based on a global description of plasma in the typical geometry of the magnetron discharges obtained in independent research. The structure of the resulting layer is investigated. © Published under licence by IOP Publishing Ltd.
The article devoted to construction of an automated test complex for parametric and functional control of vibra-sensors ICs (such as integrated accelerometers and MEMS-generators). The test complex based on PXI-standard measurement devices and controlled by LabVIEW soft. The complex's characteristics was confirmed by calibration service and been certified. © The Authors, published by EDP Sciences, 2016.
This paper describes a custom developed automated test complex for linear voltage-to-frequency converter based on PXI-standard equipment managed by LabView software. The main parts of block diagram are described in detail. The complex was successfully applied in test experiments. © 2016 IEEE.
Anomalously slow relaxation of clusters of a liquid confined in a disordered system of pores has been studied for the (water-L23 nanoporous medium) system. The evolution of the system of confined liquid clusters consists of a fast formation stage followed by slow relaxation of the system and its decay. The characteristic time for the formation of the initial state is τp∼10 s after the reduction of excess pressure after complete filling. Anomalously slow relaxation has been observed for times of 101-105 s, and decay has been observed at times of >105 s. The time dependence of the volume fraction θ of pores filled with the confined liquid is described by a power law θ∼t-α with the exponent α<0.15. The exponent α and temperature dependence α(T) are qualitatively described theoretically for the case of a slightly polydisperse medium in a mean-field approximation with the inclusion of the interaction of liquid clusters and averaging over various degenerate local configurations of clusters. In this approximation, slow relaxation is represented as a continuous transition through a sequence of metastable states of the system of clusters with a decreasing barrier. © 2016 American Physical Society.
We propose a physical model of a relaxation of states of clusters of nonwetting liquid confined in a random nanoporous medium. The relaxation is occurred by the self-organized criticality (SOC) scenario. Process is characterized by waiting for fluctuation necessary for overcoming of a local energy barrier with the subsequent avalanche hydrodynamic extrusion of the liquid by surface forces of the nonwetting frame. The dependence of the interaction between local configurations on the number of filled pores belonging to the infinite percolation cluster of filled pores serves as an internal feedback initiating the SOC process. The calculations give a power-law time dependence of the relative volume θ of the confined liquid θ∼t-ν (ν∼0.2) as in the picture of relaxation in the mean field approximation. The model of the relaxation of the porous medium with the nonwetting liquid demonstrates possible mechanisms and scenarios of SOC for relaxation of other disordered systems. © 2016 Elsevier B.V.
It has been shown that changes in the energy of a system of nonwetting liquid clusters confined in a random nanoporous medium in the process of relaxation can be written in the quasiparticle approximation in the form of the sum of the energies of local (metastable) configurations of liquid clusters interacting with clusters in the connected nearest pores. The energy spectrum and density of states of the local configuration have been calculated. It has been shown that the relaxation of the state of the system occurs through the scenario of self-organized criticality (SOC). The process is characterized by the expectation of a fluctuation necessary for overcoming a local energy barrier of the metastable state with the subsequent rapid hydrodynamic extrusion of the liquid under the action of the surface buoyancy forces of the nonwetting framework. In this case, the dependence of the interaction between local configurations on the number of filled pores belonging to the infinite percolation cluster of filled pores serves as an internal feedback initiating the SOC process. The calculations give a power-law time dependence of the relative volume of the confined liquid θ∼supt-α/sup(α∼0.1). The developed model of the relaxation of the porous medium with the nonwetting liquid demonstrates possible mechanisms and scenarios of SOC for disordered atomic systems. © 2016 Elsevier B.V. All rights reserved.
We propose a numerical model of outflow of the nonwetting liquid from previously completely filled nanoporous media based on cellular automata theory. It was shown that the relaxation of this system has an avalanche-like behaviour, which is inherent to phenomenon of self-organized criticality (SOC). Avalanche size and energy distributions were obtained. It was found that spectra have a typical for SOC theory power-law dependence N(s) ∼ ssup-β/sup with β = 2.73, and N(E) ∼ E-βsupen/sup with βsupen/sup = 2.25. © Published under licence by IOP Publishing Ltd.
The disordered system of pores in a random nanoporous medium can be filled with a non-wetting liquid at excess pressure. It has been established that, when the porous medium is completely filled and excess pressure is then removed, a part of the liquid can remain in the disordered porous medium. This means that the state of the confined non-wetting liquid is an effectively "wetting" (metastable) state in the disordered confinement of the porous medium. The metastable state relaxation of the confined non-wetting liquid dispersed in the disordered nanoporous medium has been experimentally observed for systems consisting of water and grafted silica gels. In this work, time and temperature dependences of the volume fraction of the non-wetting liquid dispersed in the nanoporous medium have been obtained for three grafted nanoporous media (Libersorb 23, Fluka 100 C18 and Fluka 100 C8) with different pore size distribution functions (PSDs). It has been shown that the PSD, (liquid-grafted solid surface) interaction and temperature strongly affect the experimental dependences obtained. The time dependences of the volume fraction of the non-wetting liquid have been approximated by power law functions for different temperatures. The volume fraction of the confined liquid decreases in time according to a power law as was predicted in [V.D. Borman et al., Phys. Rev. E 88, 052116 (2013)]. Thus, the observed relaxation of the metastable state can be described as a discrete equilibrium process with the overcoming of numerous local maxima appearing because of random local configurations of filled and empty pores with various sizes in the disordered porous medium. © 2015 Elsevier B.V.
The relaxation of the system of the nanoporous medium with the nonwetting liquid is a self-organized criticality process characterized by waiting for fluctuation necessary for overcoming a barrier of local metastable state with the subsequent avalanche decay of local metastable configurations of pores. The dependence of the interaction between local configurations on the number of filled pores belonging to the infinite percolation cluster of filled pores serves as an internal feedback initiating the SOC process. © Published under licence by IOP Publishing Ltd.
Three-dimensional (3D) Bragg coherent x-ray diffractive imaging (CXDI) with a nanofocused beam was applied to quantitatively map the internal strain field of a single indium phosphide nanowire. The quantitative values of the strain were obtained by pre-characterization of the beam profile with transmission ptychography on a test sample. Our measurements revealed the 3D strain distribution in a region of 150 nm below the catalyst Au particle. We observed a slight gradient of the strain in the range of +/- 0.6% along the  growth direction of the nanowire. We also determined the spatial resolution in our measurements to be about 10 nm in the direction perpendicular to the facets of the nanowire. The CXDI measurements were compared with the finite element method simulations and show a good agreement with our experimental results. The proposed approach can become an effective tool for in operando studies of the nanowires.
We study the formation of the directed flow of hadrons in nuclear collisions at energies between AGS and SPS in Monte Carlo cascade model. The slope of the proton flow at midrapidity tends to zero (softening) with increasing impact parameter of the collision. For very peripheral topologies this slope becomes negative (antiflow). The effect is caused by rescattering of hadrons in remnants of the colliding nuclei. Since the softening of the proton flow can be misinterpreted as indication of the presence of quark-gluon plasma, we propose several measurements at NICA facility which can help one to distinguish between the cases with and without the plasma formation. © 2016, SIF, Springer-Verlag Berlin Heidelberg.
The Langevin and diffusion equations for statistical velocity and displacement of marked fluid particles are formulated for turbulent flow at large Reynolds number for which Lagrangian Kolmogorov K-41 theory holds. The damping and diffusion terms in these equations are specified by the first two terms of a general expansion in powers of (Formula presented.) where C0 is Lagrangian based universal Kolmogorov constant: (Formula presented.). The equations enable the derivation of descriptions for transport by turbulent fluctuations of conserved scalars, momentum, kinetic energy, pressure and energy dissipation as a function of the derivative of their mean values. Except for pressure and kinetic energy, the diffusion coefficients of these relations are specified in closed-form with (Formula presented.) as constant of proportionality. The relations are verified with DNS results of channel flow at Reτ=2000. The presented results can serve to improve or replace the diffusion models of current CFD models. © 2016 The Author(s)
Design of SLVS chip-to-chip communication transmitter/receiver IP block in 180 nm UMC MMRF CMOS process is presented. This block has been developed for study a data transmission over PCBs and/or electrical cables (lines) of few meters length at rates up to 320 Mb/s. Schematic for on-chip tests is also presented. This blocks are used for communication between front-end ASICs and DAQ system.
We present high precision measurements of elliptic flow near midrapidity (|y|<1.0) for multistrange hadrons and φ meson as a function of centrality and transverse momentum in Au+Au collisions at center of mass energy sNN=200 GeV. We observe that the transverse momentum dependence of φ and Ω v2 is similar to that of π and p, respectively, which may indicate that the heavier strange quark flows as strongly as the lighter up and down quarks. This observation constitutes a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. Number of constituent quark scaling is found to hold within statistical uncertainty for both 0%-30% and 30%-80% collision centrality. There is an indication of the breakdown of previously observed mass ordering between φ and proton v2 at low transverse momentum in the 0%-30% centrality range, possibly indicating late hadronic interactions affecting the proton v2. © 2016 American Physical Society.
Elliptic flow (v2) values for identified particles at midrapidity in Au + Au collisions measured by the STAR experiment in the Beam Energy Scan at the Relativistic Heavy Ion Collider at sNN=7.7-62.4 GeV are presented for three centrality classes. The centrality dependence and the data at sNN=14.5 GeV are new. Except at the lowest beam energies, we observe a similar relative v2 baryon-meson splitting for all centrality classes which is in agreement within 15% with the number-of-constituent quark scaling. The larger v2 for most particles relative to antiparticles, already observed for minimum bias collisions, shows a clear centrality dependence, with the largest difference for the most central collisions. Also, the results are compared with a multiphase transport (AMPT) model and fit with a blast wave model. © 2016 American Physical Society.
Jet production rates are measured in p+p and d+Au collisions at sNN=200 GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Jets are reconstructed using the R=0.3 anti-kt algorithm from energy deposits in the electromagnetic calorimeter and charged tracks in multiwire proportional chambers, and the jet transverse momentum (pT) spectra are corrected for the detector response. Spectra are reported for jets with 12<pT<50 GeV/c, within a pseudorapidity acceptance of |η|<0.3. The nuclear-modification factor (RdAu) values for 0%-100% d+Au events are found to be consistent with unity, constraining the role of initial state effects on jet production. However, the centrality-selected RdAu values and central-to-peripheral ratios (RCP) show large, pT-dependent deviations from unity, challenging the conventional models that relate hard-process rates and soft-particle production in collisions involving nuclei. © 2016 American Physical Society.
As a result of operation of the Mayak Production Association (Mayak PA), Chelyabinsk Oblast, Russia, an enterprise for production and separation of weapon-grade plutonium in the Soviet Union, ecosystems of a number of water bodies have been radioactively contaminated. The article presents information about the current state of ecosystems of 6 special industrial storage reservoirs of liquid radioactive waste from Mayak PA: reservoirs R-3, R-4, R-9, R-10, R-11 and R-17. At present the excess of the radionuclide content in the water of the studied reservoirs and comparison reservoirs (Shershnyovskoye and Beloyarskoye reservoirs) is 9 orders of magnitude for Sr-90 and Cs-137, and 6 orders of magnitude for alpha-emitting radionuclides. According to the level of radioactive contamination, the reservoirs of the Mayak PA could be arranged in the ascending order as follows: R-11, R-10, R-4, R-3, R-17 and R-9. In 2007-2012 research of the status of the biocenoses of these reservoirs in terms of phytoplankton, zooplankton, bacterioplankton, zoobenthos, aquatic plants, ichthyofauna, avifauna parameters was performed. The conducted studies revealed decrease in species diversity in reservoirs with the highest levels of radioactive and chemical contamination. This article is an initial descriptive report on the status of the biocenoses of radioactively contaminated reservoirs of the Mayak PA, and is the first article in a series of publications devoted to the studies of the reaction of biocenoses of the fresh-water reservoirs of the Mayak PA to a combination of natural and man-made factors, including chronic radiation exposure. (C) 2015 Elsevier Ltd. All rights reserved.
Solid-state radiation imaging detectors based on photoluminescent colour centres in lithium fluoride (LiF) crystals have been successfully tested for both advanced 2D and 3D characterizations of X-ray polycapillary optics by a table-top laboratory system. Polycapillary optics can control X-ray beams propagation and allows obtaining quasi-parallel beam (half-lens) or focused beams (full-lens). The combination of a fine-focused micro X-ray tube and a polycapillary lens can provide the high intensity radiation fluxes that are necessary for high resolution X-ray imaging. In this paper we present novel results about advanced characterization of these complex optics by 2D as well as 3D confocal laser fluorescence microscopy of X-ray irradiated LiF crystal detectors. Two dimensional high spatial resolution images on a wide field of view of transmitted X-rays through a semi-lens and 3D direct inspection of the coloured volumes produced in LiF crystals by both focused and parallel X-ray beam transmitted by a full and a semi-lens, respectively, as well as their 3D reconstructions were obtained. The results show that the photoluminescent colour centres volume in LiF crystals combined with an optical sectioning reading system provide information about tomography of transmitted X-ray beams by policapillary optics in a single exposure process. For the first time, the use of LiF crystal plates as versatile radiation imaging luminescent detectors have been used to characterize the operation of polycapillary optics as X-ray lens, in focusing and parallel mode. © 2016 Elsevier B.V.
This paper discusses results of the study of a dark signal degradation of visible range interline transfer CCD during gamma-irradiation. © Published under licence by IOP Publishing Ltd.
We consider the radiator-converter approach at 200 MeV channeled electrons (the SPARC-LAB LNF facility energies) for the case of using W crystalline radiator and W amorphous converter. A comparison of the positron production by the axial channeling radiation and the bremsstrahlung is performed. The positron stopping in the convertor is studied by means of computer simulations. It is shown that for the maximum yield of positrons the thickness of the W amorphous converter should be taken 0.35 cm in the case of using the axial channeling radiation resulting to total yield of positrons 5 10-3 e+/e- and 0.71 cm in the case of using the bremsstrahlung resulting to total yield of positrons 3.3 10-3 e+/e-. © Published under licence by IOP Publishing Ltd.
We want to understand what drives magnetospheric dissipation in the equatorial current sheet. Numerical simulations have limitations and, unless we have a clear a priori understanding of the physical processes involved, their results can be misleading. We argue that the canonical pulsar magnetosphere is strongly dissipative and that a large fraction (up to 30-40 % in an aligned rotator) of the spindown luminosity is redirected towards the equator where it is dissipated into particle acceleration and emission of radiation. We show that this is due to the failure of the equatorial electric current to cross the Y-point at the tip of the corotating zone. © 2016 Cambridge University Press.
It has been demonstrated that photo-induced changes in the optical properties of semiconductor quantum dots (QDs) can be controlled by tuning the parameters of their laser irradiation to vary the relative contributions of photo-brightening and photo-darkening of QDs. For this purpose, the effects of the QD size, photon energy, and intensity of irradiation of QDs on the competing processes of photo-darkening and photo-brightening have been investigated. We have found that photo-brightening of QDs is not accompanied by detectable growth of their photoluminescence (PL) decay time, this process being most pronounced for QDs with an originally low PL quantum yield (QY). In this case, an increase in the PL QY is assumed to be caused by transition of some QDs from the dark (non-emissive) state to the bright (emissive) state. On the other hand, the photo-darkening effect, which was observed only under UV irradiation at 266 nm, was accompanied by simultaneous drop of both the QD QY and their PL decay time. We have also found that, at a constant dose of absorbed energy, the photo-brightening and photo-darkening processes do not depend on the excitation intensity. Thus, the photo-induced changes in the optical properties of QDs are one-photon processes. These data may help to optimize the QD operational conditions in practical applications requiring their intense excitation and add to understanding the fundamental mechanisms of the irreversible photo-induced changes that occur in colloidal QDs under illumination.
We report the measurements of correlations between event-by-event fluctuations of amplitudes of anisotropic flow harmonics in nucleus-nucleus collisions, obtained for the first time using a new analysis method based on multiparticle cumulants in mixed harmonics. This novel method is robust against systematic biases originating from nonflow effects and by construction any dependence on symmetry planes is eliminated. We demonstrate that correlations of flow harmonics exhibit a better sensitivity to medium properties than the individual flow harmonics. The new measurements are performed in Pb-Pb collisions at the center-of-mass energy per nucleon pair of sNN=2.76 TeV by the ALICE experiment at the Large Hadron Collider. The centrality dependence of correlation between event-by-event fluctuations of the elliptic v2 and quadrangular v4 flow harmonics, as well as of anticorrelation between v2 and triangular v3 flow harmonics are presented. The results cover two different regimes of the initial state configurations: geometry dominated (in midcentral collisions) and fluctuation dominated (in the most central collisions). Comparisons are made to predictions from Monte Carlo Glauber, viscous hydrodynamics, ampt, and hijing models. Together with the existing measurements of the individual flow harmonics the presented results provide further constraints on the initial conditions and the transport properties of the system produced in heavy-ion collisions. © 2016 CERN.
In this article we discussed Particle In Cell electromagnetic simulations and mechanical design of dielectric capillaries that produce THz Cherenkov Smith-Purcell radiation (ChSPR), arising when a femtosecond electron multi-bunch beam propagates through corrugated and non-corrugated dielectric capillaries with metallic radiation reflectors. We investigated the influence of the four-bunch beam on the SPR field spectrum and on the ChSPR power spectrum, and the influence of the non-central beam propagation on the ChSPR power spectrum. We also discussed the design and assembly of the capillaries, constructed as sets of cylindrical rings. © Published under licence by IOP Publishing Ltd.
The results of optimization calculations of the separative power of the ''high-speed" Iguasu gas centrifuge are presented. Iguasu gas centrifuge has the rotational speed of 1000 m/s, the rotor length of 1 m. The dependence of the optimal separative power on the pressure of the working gas on the rotor wall was obtained using the numerical simulations. It is shown, that maximum of the optimal separative power corresponds to the pressure of 1100 mmHg. Maximum value of separative power is 31.9 SWU. © Published under licence by IOP Publishing Ltd.
The measurement results of the front-end ASIC for the GEM detector read-out are presented. The MUCH ASIC v2 was designed and prototyped via Europractice by means of the 0.18 um CMOS MMRF process of UMC (Taiwan). The parameters of the analog channels, including the CSA, fast and slow shapers, discriminators, were measured. The channels provide a sufficient dynamic range of 100 fC, low power consumption of 10 mW per channel and ENC of 1550 el at a 50 pF detector capacitance. © 2016 IOP Publishing Ltd and Sissa Medialab srl.
A front-end prototype ASIC for muon chambers is presented. ASIC was designed and prototyped in the CMOS UMC MMRF 180 nm process via Europractice. The chip includes 8 analog processing channels, each consisting of a preamplifier, two shapers (fast and slow), differential comparator and an area efficient 6 bit SAR ADC with 1.2 mW power consumption at 50 Msps. The chip also includes the threshold DAC and digital serializer. The design has the following features: dynamic range of 100 fC, channel hit rate of 2 MHz, ENC of 1000 e- at 50 pF, power consumption of 10 mW per channel, 6 bit SAR ADC.
We present measurements of e+e- production at midrapidity in Au+Au collisions at sNN=200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass (mee<5 GeV/c2) and pair transverse momentum (pT<5 GeV/c) for minimum bias and for five centrality classes. The e+e- yield is compared to the expectations from known sources. In the low-mass region (mee=0.30-0.76 GeV/c2) there is an enhancement that increases with centrality and is distributed over the entire pair pT range measured. It is significantly smaller than previously reported by the PHENIX experiment and amounts to 2.3±0.4(stat)±0.4(syst)±0.2(model) or to 1.7±0.3(stat)±0.3(syst)±0.2(model) for minimum bias collisions when the open heavy-flavor contribution is calculated with pythia or mc@nlo, respectively. The inclusive mass and pT distributions, as well as the centrality dependence, are well reproduced by model calculations where the enhancement mainly originates from the melting of the ρ meson resonance as the system approaches chiral symmetry restoration. In the intermediate-mass region (mee=1.2-2.8 GeV/c2), the data hint at a significant contribution in addition to the yield from the semileptonic decays of heavy-flavor mesons. © 2016 American Physical Society.
The descriprion of ultrarelativistic classical particles' movement in interference laser field formed by multichannel ''sandwich" structures taking into account the radiative energy losses is present. The muon channeling case is described in detail. The critical angle for muon bound motion in the potential well of laser field is defined. The feasibility of beam cooling for charged particles due to radiation losses is shown. © Published under licence by IOP Publishing Ltd.
A dispersion transition in the Fluka 100 C8 and Fluka 100 C18 hydrophobic silica gels close in structural characteristics has been studied. Nonlinear dependences of the volume of the trapped liquid on the degree of filling, which have not yet been observed at the interaction of nonwetting liquids with nanoporous media, have been revealed. Two critical temperatures T-c 1 approximate to 330 K and T-c2 approximate to 340 K have been found for the Fluka 100 C18-water system. At a temperature above T-c1, a transition occurs at a degree of filling of similar to 0.6 from the state of the system with a linear increase in the volume of the trapped liquid with the degree of filling to the state in which the dispersion transition occurs at similar to 0.6. At temperatures above T-c2, the fraction of the trapped liquid is small and independent of the temperature and degree of filling. When Fluka 100 C8 is filled with water, no abrupt change in the volume of the trapped liquid with an increase in the degree of filling has been detected in the temperature range under study of T = 300-360 K. In this case, a linear increase in the volume of the trapped liquid with the degree of filling has been observed.
Context. Helical magnetic fields embedded in the jets of active galactic nuclei (AGNs) are required by the broad range of theoretical models that advocate for electromagnetic launching of the jets. In most models, the direction of the magnetic field is random, but if the axial field is generated by a Cosmic Battery generated by current in the direction of rotation in the accretion disk, there is a correlation between the directions of the spin of the AGN accretion disk and of the axial field, which leads to a specific direction for the axial electric current, azimuthal magnetic field, and the resulting observed transverse Faraday-rotation (FR) gradient across the jet, due to the systematic change in the line-of-sight magnetic field. Aims. We consider new observational evidence for the presence of a nested helical magnetic-field structure such as would be brought about by the operation of the Cosmic Battery, and make predictions about the expected behavior of transverse FR gradients observed on decaparsec and kiloparsec scales. Methods. We have jointly considered 27 detections of transverse FR gradients on parsec scales, four reports of reversals in the directions of observed transverse FR gradients observed on parsec-decaparsec scales, and five detections of transverse FR gradients on decaparsec-kiloparsec scales, one reported here for the first time. We also consider seven tentative additional examples of transverse FR gradients on kiloparsec scales, based on an initial visual inspection of published Very Large Array FR maps of 85 extragalactic radio sources, for three of which we have carried out quantitative analyses in order to quantitatively estimate the significances of the gradients. Results. The data considered indicate a predominance of transverse FR gradients in the clockwise direction on the sky (i.e., net axial current flowing inward in the jet) on parsec scales and in the counter-clockwise direction on the sky (i.e., net axial current flowing outward) on scales greater than about 10 pc, consistent with the expectations for the Cosmic Battery. The predominance of counter-clockwise FR gradients on larger scales has been established at the 3 sigma confidence level. Conclusions. The collected results provide evidence for a reversal in the direction of the net azimuthal magnetic field determining the ordered component of the observed FR images, with distance from the jet base. This can be understood if the dominant azimuthal field on parsec scales corresponds to an axial electric current flowing inward along the jet, whereas the (weaker) dominant azimuthal field on kiloparsec scales corresponds to a outward-flowing current in the outer sheath of the jet and/or an extended disk wind. This is precisely the current/magnetic field structure that should be generated by the Cosmic Battery.
Multiple small-angle neutron scattering by a high-density system of inhomogeneities has been considered. A combined approach to the analysis of multiple small-angle neutron scattering has been proposed on the basis of the synthesis of the Zernike-Prince and Moli,re formulas. This approach has been compared to the existing multiple small-angle neutron scattering theory based on the eikonal approximation. This comparison has shown that the results in the diffraction limit coincide, whereas differences exist in the refraction limit because the latter theory includes correlations between successive scattering events. It has been shown analytically that the existence of correlations in the spatial position of scatterers results in an increase in the number of unscattered neutrons. Thus, the narrowing of spectra of multiple small-angle neutron scattering observed experimentally and in numerical simulation has been explained.
A problem, which concerns the effect of the diamond heat-spreading layer on the temperature and voltage-current characteristics of gallium nitride (GaN) high-electron-mobility transistors (HEMTs) is solved for the first time in a hydrodynamic model (which includes the continuity equation, Poisson equation, and equations for electron and lattice temperatures). The mechanism of the occurrence of peak electron and lattice temperatures (hot spots) is analyzed. It is shown that introducing a heat spreader considerably reduces the maximum temperature (by 263 K for a sapphire substrate and by 163 K for a silicon carbide substrate) and improves the voltage-current characteristics. The effectiveness of the heat spreader is evaluated depending on its thickness, gate size, and substrate material to find the optimum design. © 2016, Pleiades Publishing, Ltd.
Mixed matrix membranes (MMMs) with unique transport characteristics can be prepared by the addition of the minor amounts of carbon nanotubes. Qualitative (critical, effective, marked) changes in the membrane performance are shown to be provided by the formation of a percolation cluster composed of nanotubes. For MMMs based on poly(trimethylvinylsilane) (PVTMS) containing carbon nanotubes (CNT), due to the formation of the CNT percolation cluster, gas permeability increases by a factor of 5-15. When the CNT content in the MMMs is higher than the percolation threshold, gas permeability remains on the same level or even decreases. Numerical simulation proves that the above negative changes are provided by the agglomeration of nanotubes and subsequent deterioration of the percolation structure in the membranes. © Published under licence by IOP Publishing Ltd.
Despite a large number of studies, by now there is no any definitive explanation of the solvent transport mechanism in nanostructured polymer materials. Both convective and diffusive transport of solvents can be observed in these materials. The study of the solvents permeability at different temperatures and pressures allow the variation of the physical parameters and structure of the solvent-membrane interaction thus becoming the key factor in the understanding of the fundamental aspects of the selective transport process in nanostructured polymer membranes. The paper presents the study of ethanol, propanol and water transport through poly [1- (trimethylsilyl)-l-propine] (PTMSP) at pressures 50-150 atm and temperature up to 90°C. The study was done by the method of pressure dynamic decay. As the temperature rises, the permeability of ethanol and propanol through PTMSP is shown to increase in proportion to decreasing viscosity that denotes a convective type of transport. As for water, the permeability change is thermo-activated that is typical for a diffusive type of transport. This difference in the transport characteristics can be related to a change in the membrane structure and energetic characteristics of the solvent-polymer interaction. © Published under licence by IOP Publishing Ltd.
The Shubnikov–de Haas effect and the Hall effect in n-Bi2–xTlxSe3 (x = 0, 0.01, 0.02, 0.04) and p-Sb2–xTlxTe3 (x = 0, 0.005, 0.015, 0.05) single crystals are studied. The carrier mobilities and their changes upon Tl doping are calculated by the Fourier spectra of oscillations. It is found shown that Tl doping decreases the electron concentration in n-Bi2–xTlxSe3 and increases the electron mobility. In p-Sb2–xTlxTe3, both the hole concentration and mobility decrease upon Tl doping. The change in the crystal defect concentration, which leads to these effects, is discussed. © 2016, Pleiades Publishing, Ltd.
We present an experimental study of time dependent ozone treatment on post-process epitaxial graphene using both electron transport measurements and resonant micro-Raman spectroscopy. We focus on a systematic analysis of residual polymer decomposition on the epitaxial graphene on SiC substrate. It was found that graphene could be effectively cleaned by ultraviolet (UV)/ozone treatment after nanofabrication from residual lithographic polymers. This procedure improves the charge carrier mobility, almost by a factor of two for strongly contaminated samples, decreases the doping level and does not introduce defect inside the graphene lattice. It was found that epitaxial SiC graphene is extremely stable when exposed to radical oxygen atoms. We ascribe this effect to the substrate topography, which significantly affects the graphene stability under UV/ozone treatment. Our calculations reveal that surface roughness of the SiC substrate can change the energy gain from epoxy group adsorption by a few tenths of electron volts. © 2016 Elsevier Ltd
The article presents the hardware-software complex for functional and parametric tests of ARM microcontrollers STM32F1XX. The complex is based on PXI devices by National Instruments and LabVIEW software environment. Data exchange procedure between a microcontroller under test and the complex hardware is describes. Some test results are also presented. © The Authors, published by EDP Sciences, 2016.
The absolute polarimeter based on the elastic pp-scattering in the diffraction kinematic regions with the total momentum transfer squared coverage of 0.1 -t 0.3 (GeV/c)(2) is proposed for the polarized antiproton beam at the U-70 proton synchrotron of IHEP. It is shown that it would take similar to 200-400 hours for measuring the beam polarization at the statistical errors of Delta P-B/P-B similar or equal to 10-15%. These time estimates include also the time which is necessary for the measurements of an analyzing power A(N), using a polarized target. Besides the measurements of beam polarizations, the proposed polarimeter provides an opportunity for carrying out the experimental studies of the small momentum transfers physics which would be a valuable enrichment of the SPASCHARM experiment capabilities and its physics program.
The possible physical mechanism of ELDRS effect in the silicon-germanium (SiGe) bipolar transistors for room and low-temperature irradiation is described. The mechanism is connected with narrowing of the bandgap in transistor base region due to Ge content. © 2016 Elsevier Ltd.
In(Formula presented.)Ga(Formula presented.)As/In(Formula presented.)Al(Formula presented.)As HEMT structures (Formula presented.)-doped by Si were grown by molecular beam epitaxy on InP substrate. We investigated the influence of the In content on the electron mobilities and effective masses in dimensionally quantized subbands. The electron effective masses were determined by the temperature dependence of the amplitude of the Shubnikov–de Haas effect at 1.6 and 4.2 K. We found that the more the In content in quantum well (QW), the less the electron effective masses. The mobilities are higher in HEMT structures with wider and deeper QW. The energy band diagrams were calculated by using Vegard’s law for basic parameters. The calculated band diagrams are in a good agreement with the experimental data of photoluminescence spectra. © 2016 Springer Science+Business Media New York
The structure and ligand-localized excited-states of [Eu(cfqH) (cfq)(H2O)(4)]Cl-2 (cfqH is ciprofloxacin) are studied by XMCQDPT2/CASSCF with full geometry optimization. The complex includes one anionic and one zwitterionic ligand. Two low-lying triplet states, both localized on the anionic ligand, are found. One of them has sufficient energy to transfer to the D-5(1) sublevel of Eu3+, because its T-S0 vertical transition energy is equal (or very close) to the F-7(0)-D-5(1) Eu3+ excitation energy. The other triplet state has a very small S0-T1 gap, which favors fast nonradiative relaxation. Two other triplet states are localized on the zwitterionic ligand. One low-lying excited singlet state (S1) is localized on the anionic ligand; the other excited singlet is localized on the zwitterionic one. Spin-orbit coupling constants were calculated for the relaxed geometry of each state (ground state, two low-lying triplets, and one low-lying excited singlet) by spin-orbit configuration interaction (CI) with Pauli-Breit Hamiltonian. Large spin-orbit coupling constants between S1 and both triplets together with small energy gaps are indicative of fast intersystem crossing (ISC) from the excited singlet state to the triplet manifold. This ISC process is followed by energy transfer from the ligand-localized triplet states to the D-5(1) sublevel of Eu3+. However, relatively large spin-orbit coupling constants between S0 and one of the triplet states together with the small. T-S0 energy gap shows that this state can decay, without transferring its energy to Eu3+. This mechanism is expected to be common for other Ln(3+)-fluoroquinolone complexes.
The elliptic flow of electrons from heavy-flavour hadron decays at mid-rapidity (|y| 0.7) is measured in Pb-Pb collisions at TeV with ALICE at the LHC. The particle azimuthal distribution with respect to the reaction plane can be parametrized with a Fourier expansion, where the second coefficient (v (2)) represents the elliptic flow. The v (2) coefficient of inclusive electrons is measured in three centrality classes (0-10%, 10-20% and 20-40%) with the event plane and the scalar product methods in the transverse momentum (p (T)) intervals 0.5-13 GeV/c and 0.5-8 GeV/c, respectively. After subtracting the background, mainly from photon conversions and Dalitz decays of neutral mesons, a positive v (2) of electrons from heavy-flavour hadron decays is observed in all centrality classes, with a maximum significance of 5.9 sigma in the interval 2 p (T) 2.5 GeV/c in semi-central collisions (20-40%). The value of v (2) decreases towards more central collisions at low and intermediate p (T) (0.5 p (T) 3 GeV/c). The v (2) of electrons from heavy-flavour hadron decays at mid-rapidity is found to be similar to the one of muons from heavy-flavour hadron decays at forward rapidity (2.5 y 4). The results are described within uncertainties by model calculations including substantial elastic interactions of heavy quarks with an expanding strongly-interacting medium.
Unknown force-field parameters for metal organic beryllium complexes used in emitting and electron transporting layers of OLED structures are determined. These parameters can be used for the predictive atomistic simulations of the structure and properties of amorphous organic layers containing beryllium complexes. The parameters are found for the AMBER force field using a relaxed scan procedure and quantum-mechanical DFT calculations of potential energy curves for specific internal (angular) coordinates in a series of three Be complexes (Bebq2; Be(4-mpp)2; Bepp2). The obtained parameters are verified in calculations of some molecular and crystal structures available from either quantum-mechanical DFT calculations or experimental data. [Figure not available: see fulltext.] © 2016, Springer-Verlag Berlin Heidelberg.
Phthalocyanine-functionalized plasmonic sensing systems are typically based on Kretschmann configuration. Such scheme of detection utilizes spectral or angular modulation of reflected light, which is induced by surface plasmon's excitation in the metal film on prism. Phthalocyanine's layer plays a role of analyte adsorber. In present paper we offer another approach to phthalocyanine-plasmonic sensing, where both local surface plasmon resonance and optical absorption of phthalocyanines are simultaneously detected. Hybrid Ag nanoparticles (AgNps) - low symmetrical A3B zinc phthalocyanine (ZnPc) thin films were prepared, and their NO2 gas sensitive properties were examined. Since the plasmon resonance of AgNps was properly tuned to charge-transfer band of ZnPc-NO2 complex, we found out more than two-fold increase of the optical response to NO2 exposure in AgNps-ZnPc thin films compared to ZnPc films without AgNps. © Published under licence by IOP Publishing Ltd.
It has been shown recently that Q-cascade with an expansion of the entering flow at the intermediate withdrawal point is able to obtain a concentration of an intermediate component far exceeding the concentration limit available from an end withdrawal. To enhance the applicability of this approach, it is necessary to reduce the relative total flow while maintaining the concentration of the intermediate target component unchanged. Optimization is carried out by using the technique of cascade segmentation, and using the mass numbers of the virtual components in the segments and the lengths of the segments as decision variables. The results demonstrate that the relative total flow is considerably reduced through optimization. © Published under licence by IOP Publishing Ltd.
The lack of systematlzation and a planning procedure of the process of preparation of sports maps for training and competition purposes in the situation of the growing number of contests threatens to become a serious problem in the near future. In this paper, the researchers were the first to pay attention to solving this problem and aim to determine the volume of sports maps to be prepared for the year and to describe the economic aspects of the process. Based on statistical analysis and collection of the data related to orienteering competitions that have been held in a metropolis conditions throughout the last 15 years, the data obtained are analyzed and conclusions are made on the correspondence of the current program of development of sports mapping in the Moscow metropolis to the real needs of the competition schedule. The main results are the practical guidelines in terms of the volume of sports maps to be prepared. In addition, estimates of the necessary funding program for preparation of sports maps and the mechanisms of its implementation can be found in the given paper.
The Solenoidal Tracker At RHIC (STAR) uses the Time Projection Chamber (TPC) to perform tracking and particle identification. In order to improve the corrections (such as space charge) and monitor non-static distortions of the TPC, GEM-based chambers (GMT) were installed at eight locations outside the TPC where they will provide optimal sensitivity to the distortions. In order to reach this goal, the ionization clusters were measured by using the ADC signals in each module. The positions of clusters and their deviations from track projections enabled alignment of the GMT modules with respect to TPC to an accuracy ti 200 m.
The possibility of the recovered uranium enrichment in a cascade of gas centrifuges with three feed flows (depleted uranium, low-enriched uranium, recovered uranium) with simultaneous dilution of U-232,234,236 isotopes was shown. A series of numerical experiments were performed for different content of U-235 in low-enriched uranium. It has been demonstrated that the selected combination of diluents can simultaneously reduce the cost of separative work and the consumption of natural uranium, not only with respect to the previously used multi-flow cascade schemes, but also in comparison to the standard cascade for uranium enrichment. © Published under licence by IOP Publishing Ltd.
The paper presents the results of experimental studies of impact filling of nanoporous medium with non-wetting liquid. With increasing the impact energies nontrivial pattern of pressure changes in the system over time is observed. A physical explanation is proposed for the observed phenomena. © Published under licence by IOP Publishing Ltd.
The lack of models describing the propagation of X-rays in waveguides and the interference mechanism between incident and reflected radiation waves hamper the understanding and the control of wave propagation phenomena occurring in many real systems. Here, experimental spectra collected at the exit of microchannel plates (MCPs) under the total X-ray reflection condition are presented. The results are discussed in the framework of a theoretical model in which the wave propagation is enhanced by the presence of a transition layer at the surface. The angular distributions of the propagating radiation at the exit of these MCPs with microchannels of ∼3 μm diameter will also be presented and discussed. These spectra show contributions associated with the reflection of the primary monochromatic beam and with the fluorescence radiation originating from the excitation of atoms composing the surface of the microchannel. The soft X-ray fluorescence spectra collected at the exit of microcapillaries were analyzed in the framework of a wave approximation while diffraction contributions observed at the exit of these hollow X-ray waveguides have been calculated using the Fraunhofer diffraction model for waves in the far-field domain. Data collected at the Si L-edge show that in glassy MCPs the fluorescence radiation can be detected only when the energy of the primary monochromatic radiation is above the absorption edge for grazing angles higher than half of the critical angle of the total reflection phenomenon. Experimental data and simulations of the propagating radiation represent a clear experimental confirmation of the channeling phenomenon of the excited fluorescence radiation inside a medium and point out that a high transmission can be obtained in waveguide optics for parameters relevant to X-ray imaging. © 2016 International Union of Crystallography.
The influence of current density and pressure gradient profiles in the pedestal on the access to the regimes free from edge localized modes (ELMs) like quiescent H-mode in ITER is investigated. Using the simulator of MHD modes localized near plasma boundary based on the KINX code, calculations of the ELM stability were performed for the ITER plasma in scenarios 2 and 4 under variations of density and temperature profiles with the self-consistent bootstrap current in the pedestal. Low pressure gradient values at the separatrix, the same position of the density and temperature pedestals and high poloidal beta values facilitate reaching high current density in the pedestal and a potential transition into the regime with saturated large scale kink modes. New version of the localized MHD mode simulator allows one to compute the growth rates of ideal peeling-ballooning modes with different toroidal mode numbers and to determine the stability region taking into account diamagnetic stabilization. The edge stability diagrams computations and sensitivity studies of the stability limits to the value of diamagnetic frequency show that diamagnetic stabilization of the modes with high toroidal mode numbers can help to access the quiescent H-mode even with high plasma density but only with low pressure gradient values at the separatrix. The limiting pressure at the top of the pedestal increases for higher plasma density. With flat density profile the access to the quiescent H-mode is closed even with diamagnetic stabilization taken into account, while toroidal mode numbers of the most unstable peeling-ballooning mode decrease from n = 10-40 to n = 3-20.
We study the physical origin of extreme optical chirality of subwavelength arrays of chiral holes in metal. We reconstruct the nanoscale relief of the hole arrays by the atomic-force microscopy and post-process the data to acquire an average unit-cell shape clear of noise and defects. For this shape, we perform the electromagnetic finite difference time domain simulations that reproduce all important features observed by the light-transmission experiments, including the notably strong circular dichroism and optical activity covering the whole range of possible values. To interpret the simulation results, we develop a chiral coupled-mode model which yields analytical expressions that fit accurately the numerical data in a broad wavelength range. Our conclusions undoubtedly link the extreme optical chirality to the plasmon resonances of chiral holes and the associated chiral Fano-type transmission resonance. © 2016 American Physical Society.
The target of this work is the demonstration of advanced novel approaches able to provide rapid prototyping by using laser technology ceramic MEMS platforms for chemical sensor operating under harsh environmental conditions and, on the other hand, to assure microhotplate stable at high temperature, which can be used for the deposition of high working temperature gas sensing materials, for example, oxides of tin, gallium, zirconium and hafnium. As substrate ceramic material in work using alumina oxide. © Springer Science+Business Media Singapore 2016.
This study is devoted to the search for new possibilities of characterizing crystal-structure features using high-resolution X-ray diffraction. The emphasis is on the scanning mode across the diffraction vector (ω-scanning), since researchers usually pay little attention to this mode, and its capabilities have not yet been completely revealed. For the  and [01$$1$$] directions, the ω-peak half-width and the average tilt angle of the sample surface profile are compared. The diagnostic capabilities of X-ray scattering mapping are also studied. The objects of study are semiconductor nanoheterostructures with an InAlAs/InGaAs/InAlAs quantum well and an InxAl1–xAs metamorphic buffer grown by molecular-beam epitaxy on InP and GaAs substrates. Such nanoheterostructures are used to fabricate microwave transistors and monolithic integrated circuits. The objects under study are more completely characterized using the Hall effect, atomic-force microscopy, and low-temperature photoluminescence spectroscopy at 79 K. © 2016, Pleiades Publishing, Ltd.
The formation of multifunctional ordered arrays of detonation diamond particles is studied during self-assembling in spin coating of films of evaporating microdroplets. It is shown that the most homogeneous layer of diamond particles on a crystalline silicon substrate forms at a rate of substrate rotation of 8000 minsup–1/sup, whereas a relation between the distribution of particles and the radius is clearly detected at rates of about 2000 minsup–1/sup. As the rate of substrate rotation increases from 2500 to 8000 minsup–1/sup, the density of the coating of a silicon substrate with diamond nanoparticles decreases approximately threefold. A model is proposed to estimate the increase in the number of individual diamond “points” with the substrate rotation frequency. © 2016, Pleiades Publishing, Ltd.
The invariant yields, dN/dy, for J/ψ production at forward rapidity (1.2<|y|<2.2) in U+U collisions at sNN=193GeV have been measured as a function of collision centrality. The invariant yields and nuclear-modification factor RAA are presented and compared with those from Au+Au collisions in the same rapidity range. Additionally, the direct ratio of the invariant yields from U+U and Au+Au collisions within the same centrality class is presented, and used to investigate the role of cc¯ coalescence. Two different parametrizations of the deformed Woods-Saxon distribution were used in Glauber calculations to determine the values of the number of nucleon-nucleon collisions in each centrality class, Ncoll, and these were found to give significantly different Ncoll values. Results using Ncoll values from both deformed Woods-Saxon distributions are presented. The measured ratios show that the J/ψ suppression, relative to binary collision scaling, is similar in U+U and Au+Au for peripheral and midcentral collisions, but that J/ψ show less suppression for the most central U+U collisions. The results are consistent with a picture in which, for central collisions, increase in the J/ψ yield due to cc¯ coalescence becomes more important than the decrease in yield due to increased energy density. For midcentral collisions, the conclusions about the balance between cc¯ coalescence and suppression depend on which deformed Woods-Saxon distribution is used to determine Ncoll. © 2016 American Physical Society.
Developed automated setup for functional and parametrical control of temperature sensors is presented. The hardware setup is based on the NI myRIO operated under LabVIEW software. Two ways of communication with the temperature sensor, advantages and disadvantages are described. The experimental results functional and parametrical control for three temperature sensors are presented. © The Authors, published by EDP Sciences, 2016.
Basics of the radiochemical physics of the Earth atmosphere are discussed. This area of science studies the resonance interactions of the electromagnetic waves with the gaseous media containing the Rydberg molecular complexes that occupy D and E layers of the upper atmosphere during solar flares. This interaction is responsible for the distortion of the signals from the satellite groups. The radiation transitions between orbitally degenerate states of these complexes form the non-coherent additional background radiation on the radio (UHV) and infrared (IR) ranges. The radiation in these wave ranges is of primary importance in a number of fundamental researches and is widely used in some technical applications. The areas considered in this paper include: the dynamics of processes in the upper atmosphere during increase of solar activity leading to the formation of incoherent additional background radiation; the distant passive location of the soil humidity and the salinity of the ocean waters; the distant radio sounding of the electromagnetic properties of the surface layers of the Earth for determining their structure and content; the technology of efficient and uninterrupted operation of energy networks by synchronizing the measuring equipment in view of the possible failures of the satellite signals; the use of the global positioning systems as a tool for monitoring the state of the atmosphere. In the present work the description is given of the most perspective applications of the above mentioned areas of the radiochemical physics of the atmosphere whose robustness is substantially depends on the current state of the upper atmosphere. We analyze the problems that arise here and provide their specific solutions. The prospects for the development of these applications are discussed, as well as those areas of research that are just coming up. © 2016, Pleiades Publishing, Ltd.
The γ-ray data of Fermi-LAT on the giant lobes of Centaurus A are analysed together with the high frequency radio data obtained with the Planck satellite. The large γ-ray photon statistics, accumulated during seven years of observations, and the recently updated Fermi-LAT collaboration software tools allow substantial extension of the detected γ-ray emission towards higher energy, up to 30 GeV, and lower energy, down to 60 MeV. Moreover, the new γ-ray data allow us to explore the spatial features of γ-ray emission of the lobes. For the north lobe, we confirm, with higher statistical significance, our earlier finding on the extension of γ-ray emission beyond the radio image. Moreover, the new analysis reveals significant spatial variation of γ-ray spectra from both lobes. On the other hand, the Planck observations at microwave frequencies contain important information on spectra of synchrotron emission in the cutoff region, and thus allow model-independent derivation of the strength of the magnetic field and the distribution of relativistic electrons based on the combined γ-ray and radio data. The interpretation of multiwavelength spectral energy distributions of the lobes within a pure leptonic model requires strong enhancement of the magnetic field at the edge of the south lobe. Alternatively, a more complex, leptonic-hadronic model of the γ-ray emission, postulating a non-negligible contribution of the π0-decay component at highest energies, can explain the γ-ray data with a rather homogeneous distribution of the magnetic field over the giant lobes. © ESO, 2016.
The γ-ray data of Fermi-LAT on the giant lobes of Centaurus A are analysed together with the high frequency radio data obtained with the Planck satellite. The large γ-ray photon statistics, accumulated during seven years of observations, and the recently updated Fermi-LAT collaboration software tools allow substantial extension of the detected γ-ray emission towards higher energy, up to 30 GeV, and lower energy, down to 60 MeV. Moreover, the new γ-ray data allow us to explore the spatial features of γ-ray emission of the lobes. For the north lobe, we confirm, with higher statistical significance, our earlier finding on the extension of γ-ray emission beyond the radio image. Moreover, the new analysis reveals significant spatial variation of γ-ray spectra from both lobes. On the other hand, the Planck observations at microwave frequencies contain important information on spectra of synchrotron emission in the cutoff region, and thus allow model-independent derivation of the strength of the magnetic field and the distribution of relativistic electrons based on the combined γ-ray and radio data. The interpretation of multiwavelength spectral energy distributions of the lobes within a pure leptonic model requires strong enhancement of the magnetic field at the edge of the south lobe. Alternatively, a more complex, leptonic-hadronic model of the γ-ray emission, postulating a non-negligible contribution of the π0-decay component at highest energies, can explain the γ-ray data with a rather homogeneous distribution of the magnetic field over the giant lobes. © ESO, 2016.
The metastable states of a finite-size chain of N classical spins described by the chiral XY-model on a discrete one-dimensional lattice are calculated by means of a general theoretical method recently developed by one of us. This method allows one to determine all the possible equilibrium magnetic states in an accurate and systematic way. The ground state of a chain consisting of N classical XY spins is calculated in the presence of (i) a symmetric ferromagnetic exchange interaction, favoring parallel alignment of nearest neighbor spins, (ii) a uniaxial anisotropy, favoring a given direction in the film plane, and (iii) an antisymmetric Dzyaloshinskii-Moriya interaction (DMI), favoring perpendicular alignment of nearest neighbor spins. In addition to the ground state with a non-uniform helical spin arrangement, which originates from the energy competition in the finite-size chain with open boundary conditions, we have found a considerable number of higher-energy equilibrium states. In the investigated case of a chain with N=10 spins and a DMI much smaller than the in-plane uniaxial anisotropy, it turns out that a metastable (unstable) state of the finite chain is characterized by a configuration where none (at least one) of the inner spins is nearly parallel to the hard axis. The role of the DMI is to establish a unique rotational sense for the helical ground state. Moreover, the number of both metastable and unstable equilibrium states is doubled with respect to the case of zero DMI. This produces modifications in the Peierls-Nabarro potential encountered by a domain wall during its displacement along the discrete spin chain. © 2015 Elsevier B.V.
We propose a new semi-empirical method for estimation of Single Event Upset (SEU) cross section for SRAM Dual Interlocked Cells (DICE) with known distance between neighboring sensitive volumes. The method is based on experimental analysis of SEU maps in sub-100 nm 6T SRAM along with layout considerations and SPICE simulations. This method could help designers to estimate the SEE robustness of DICE cells at the design stage.
A numerical solution to the problem of transient processes in a resonant tunneling diode featuring a current–voltage characteristic with hysteresis is found for the first time in the context of a coherent model (based on the coupled Schrödinger and Poisson equations) taking into account the Fermi distribution of electrons. The transitions from the high-current to the low-current state and vice versa, which result from the existence of hysteresis and are of great practical importance for ultrafast switches based on resonant tunneling diodes, are studied in detail. It is shown that the transition times for such processes initiated by the application of a small voltage can significantly exceed the characteristic time ℏ/Γ (where G is the width of the resonance level). It is established for the first time that the transition time can be reduced and made as short as the characteristic time ℏ/Γ by applying a sufficiently high voltage. For the parameters of the resonant-tunnelingdiode structure considered in this study, the required voltage is about 0.01 V. © 2016, Pleiades Publishing, Ltd.
The influence of spatial correlations on the angular distribution of multiple small-angle neutron scattering (MSANS) at the surface layers of inhomogeneities is studied. Calculations are carried out by taking instrumental distortions into account when observing multiple small-angle neutron scattering by means of methods of a double-crystal diffractometer and a small-angle diffractometer with a position-sensitive detector. Within the framework of the eikonal approximation, the MSANS line is calculated, and the influence of the surface-layer thickness and the inhomogeneity concentration on its width is studied. © 2016, Pleiades Publishing, Ltd.
The hardware/software solution for measuring parameters of optocouplers with output MOSFET transistors using a PXI-platform and NI Labview software is proposed in the article. As an example, a typical connection circuit for an optocoupler is presented and methods of an input current adjustment using a LED and data received from the TDS-2024 oscilloscope are described. © 2016 IEEE.
The results of developing of the laboratory complex for optical spectroscopy of multiply charged thorium ions are presented. The preliminary experimental results on producing single, double and triple charged ions from solid compounds of thorium nitrate by electron beam evaporation technique are reported. It is shown that the proportion of triple and double charged thorium ions obtained by this method to single ones exceeds the values for the laser ablation technique. The electron beam evaporation technique is the basis of the developed complex. © 2014 IEEE.
XRF imaging spectrometry is a powerful tool for materials characterization. A high spatial resolution is often required, in order to appreciate very tiny details of the studied object. With respect to simple pinholes, polycapillary optics allows much more intense fluxes to be achieved. This is fundamental to detect elements in trace and to strongly reduce the global acquisition time that is actually among the main reasons, in addition to radioprotection issues, affecting the competitiveness of XRF imaging with respect to other faster imaging techniques such as multispectral imaging. Unlike other well-known X-ray optics, principally employed for high brilliant radiation source such as synchrotron facilities, polyCO can be efficiently coupled also with conventional X-ray tubes. All these aspects make them the most suitable choice to realize portable, safe and high performing mu XRF spectrometers. In this work preliminary results achieved with a novel 2D and 3D XRF facility, called Rainbow X-Ray (RXR), are reported, with particular attention to the spatial resolution achieved. RXR is based on the confocal arrangement of three polycapillary lenses, one focusing the primary beam and the other two capturing the fluorescence signal. The detection system is split in two couples of lens-detector in order to cover a wider energy range. The entire device is a laboratory user-friendly facility and, though it allows measurements on medium-size objects, its dimensions do not preclude it to be transported for in situ analysis on request, thanks also to a properly shielded cabinet.
This work reports the results of X-ray μ-tomographic investigation on the inner structure of high pressure fuel sprays. X-ray imaging is widely used in industry where non-destructive and high accuracy measurements of the samples morphology are required. A high flux beam can overcome the problems related to the low absorption of hydrocarbon chains as fossil fuels, therefore synchrotron X-ray sources are generally used for fuel sprays investigation.A desktop facility has successfully been used to characterize high pressure gasoline sprays for automotive applications. A X-ray tube coupled with polycapillary optics has been used providing a high flux beam with low divergence. In this paper the last improvements concerning quantitative measurements carried out on fuel sprays are reported. © 2015 Elsevier B.V.
We present new experimental data on the acceleration of deuterons in a small-size magnetically insulated diode. Plasma containing deuterons was created at the anode during irradiation of a TiD target by a focused laser beam with a wavelength of 1.06 μm. The accelerating voltage pulse was formed by an Arkadiev-Marx generator. A circular cathode was arranged symmetrically relative to the anode and represented a permanent ring magnet with an inner radius not exceeding 0.02 m and a magnetic induction of up to 0.4 T at the center, which ensured magnetic insulation of the accelerating gap. The experiments showed that the current of accelerated deuterons with energies of up to 300 eV can reach a level of 0.5 kA at pulse durations of ≤0.5 μs. © 2015, Pleiades Publishing, Ltd.
A method for detecting ultralow quantities of explosives in air with use a state-of-the-art picosecond chip Nd3+:YAG laser has been developed. The method combines field asymmetric ion mobility spectrometry (FAIMS) with laser ionization of examined air samples. Radiation of lambda= 266nm, tau(pulse) = 300ps, E-pulse = 30-150 mu J,. = 20-300Hz was used. Processes in the ion source for the use both picosecond and nanosecond ionization modes were analyzed. Parameters of the laser ion source have been specially optimized. The dependences on frequency, pulse energy, peak intensity, and average power for trinitrotoluene (TNT) and cyclotrimethylenetrinitramine (RDX) were obtained. It was shown that the optimal peak intensity should be no less 3.10(6) W/cm(2). The detected ion signals for all explosives were shown to be threefold higher for picosecond excitation in comparison with use a nanosecond laser of the same average power. The estimated detection threshold of the prototype equals 1.10(-15) g/cm(3). The results are promising for the development of a highly sensitive, portable laser explosive detector.
In this work comparison of the desorption effectiveness of picosecond and nanosecond laser sources (λ=266, 532 nm) were carried out to investigate the possibility of creating a non-contact sampling device for detectors of explosives on the principles of ion mobility spectrometry (IMS) and field asymmetric ion mobility spectrometry (FAIMS). The results of mass spectrometric studies of TNT (2,4,6-Trinitrotoluene), HMX (octahydro-1,3,5,7-Tetranitro-1,3,5,7-Tetrazocine), RDX (1,3,5-Trinitro-1,3,5-triazacyclohexane) laser desorption from a quartz substrate are presented. It is shown that the most effective laser source is a Nd:YAG3+ laser (λ = 266 nm; E = 1 mJ; φ = 5-10 ns; q = 108 W/cm2). The typical desorbed mass is 2 ng for RDX, 4-6 ng for TNT and 0.02 ng HMX per single laser pulse. The results obtained make it possible to create a non-contact portable laser sampling device operating in frequency mode with high efficiency. © 2015 The Authors.
Emission spectra of LT-GaAs photoconductive antennas based on epitaxial films of "low-temperature" gallium arsenide (LT-GaAs) are measured in the terahertz frequency region by the Fourier transform spectroscopy. © 2015 The Authors.
Prototypes of the gas-filled detectors based on the GEM and TGEM technologies have been studied in the multistage gas amplification circuit with the aim of selecting variants for tracking detectors of the muon system capable of operating at high counting rates in the CBM experiment. Two- and three-component mixtures based on Ar and He are used as the working gas. Their key characteristics are presented. The gas amplification factors are measured for various high-voltage modes. The charge collection times determining the response speed of the tested detectors are estimated. © 2015, Pleiades Publishing, Inc.
Prototypes of the gas-filled detectors produced on the basis of the Micromegas technology, as well as in combination with the Micromegas + GEM/TGEM structures in the multistage gas amplification circuit have been investigated with the aim of selecting variants for tracking detectors of the muon system designed for operating at high counting rates in the Compressed Baryonic Matter (CBM) experiment. Two- and three-component Ar- and He-based mixtures have been tested as the working gas. Their key characteristics are presented. The gas amplification factors are measured for various high-voltage modes, and the charge collection times determining the response speed of the tested detectors are estimated.
BiFeOinf3/inf is investigated intensively, mainly as a multiferroic material. In this paper, the state-of-the-art ab initio hybrid functional approach with atomic basis sets was employed for a study of the stability range of BiFeOinf3/inf with respect to its decomposition into binary oxides and elementary metals, as a function of temperature and oxygen partial pressure. The calculated atomic and electronic structure of BiFeOinf3/inf was compared with previous LDA+U calculations using plane-wave basis sets. Based on performed calculations, the phase diagram was constructed, which allows us to predict the stability region of stoichiometric BiFeOinf3/inf. © 2015 American Chemical Society.
3-D numerical simulation of the liquid metal flow affected by the electromagnetic field in the magnetohydrodynamic (MHD) devices is performed. Software package ANSYS has been used for the numerical calculations. The non-stationary problem has been solved taking into account the influence of the metal flow on the electromagnetic field and nonlinear magnetic permeability of the ferromagnetic cores. Simplified calculations with constant magnetic permeability of the ferromagnetic cores have been performed as well. Comparison of these calculations shows that the simulation of the MHD pump can be performed in the linear approximation. The pump performance curve has been derived in this approximation. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The application of MEMS technology for the fabrication of MOX sensors with low power consumption becomes now a very important trend in gas sensor design. However, traditional silicon technology has some evident disadvantages, when applied in high-temperature devices produced in limited batch. We present our attempt to combine the advantages of ceramic MEMS technology (high working (600°C) and technological treatment (1000°C) temperature, chemical stability at high temperature) with the advantages of additive technologies for the fabrication of functional elements of gas sensor (heaters, sensing, and catalytic layers). We developed conductive silver, gold and platinum nanoparticle (10-30 nm) inks usable in ink and aerosol jet printers and demonstrated the possibility to fabricate narrow conductive lines of microheaters and electrodes of sensor (line width ∼ 35 μm). The combination of jet printing onto thin ceramic substrate with laser cutting enables the fabrication of advanced cantilever type sensors operating in pulsing heating mode. © 2015 Published by Elsevier Ltd.
Comparison of desorption effectiveness of Nd3+: YAG nanosecond laser sources (lambda = 266, 354, 532 nm) has been carried out to investigate a possibility of creating a non-contact sampling device for detectors of explosives based on principles of ion mobility spectrometry (IMS) and field asymmetric ion mobility spectrometry (FAIMS). The results of mass spectrometric study of laser desorption of nitroamine, nitrate ester and nitroaromatic compounds from a quartz substrate are presented. It is shown that irradiation of adsorbed layers of studied samples by a single pulse of non-resonant laser radiation (lambda = 532 nm) leads to efficient desorption at laser intensity 10(7) W/cm(2) and above. Excitation of the first singlet state of nitro compounds by resonant radiation (lambda = 354 nm) provides heating of adsorbed layers and thermal desorption. A strongly non-equilibrium (non-thermal) dissociation process is developed when the second singlet state of nitroaromatic molecules is excited by radiation a lambda = 266 nm, along with thermal desorption. It is shown that Nd3+: YAG laser with wavelength lambda = 266 nm, pulse duration 5-10 ns, intensity 10(7)-10(9) W/cm(2) is the most effective source for creation a non-contact sampling device based on desorption of explosives from surfaces.
The universal ejection scheme of the reagent's preparation and input is offered in this work, wherein hydrodynamic jet-mixing devices are used. Ejectors in the system act as mixing devices, batchers and cavitators at the same time. It is possible to obtain cavitation (two-phase) liquid flow mode, basing on the assessment of cavitation number. Principle scheme of the reseach unit is offered for modelling and water treatment. In this scheme the module for reagents and air ejection is used. Furthermore, the calculation of water-moderated and water-air ejectors, working in the cavitation mode, was performed on the base of empiric equations. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The new device described in this report provides the reliable fast detection of alpha-particles at a distance from the radiation source significantly longer than the alpha-particle run in air by measuring the ions clusters, produced by alpha decay in the air. That physical fact gives possibility to develop portal monitor alpha-radioactive contamination control with absence of limitations associated with irregular configuration of surfaces; fast examination of any objects, materials addition to the human body. Design of the portal monitor for human body alpha-radioactive contamination control may use for safety inspection nuclear plants employers or in case of radiation terroristic danger is presented. © 2015 The Authors. Published by Elsevier Ltd.
The paper suggests a solution to the problem of assessing response time (RT) in an operator controlling an important or dangerous system in the process of carrying out their duties. The approach is based on distance, no contact techniques of registering biological parameters and on a personal data base. The authors discuss possibilities and necessity of using direct and indirect methods' of measuring RT in different stages of working with personnel.
Asymmetric flat-sheet membranes made of poly(vinyltrimethylsilane) (PVTMS) were studied for the regeneration of amine-based absorption solvents in a membrane gas-liquid contactor at 100°C. It was shown that PVTMS membrane possesses good mechanical and chemical stability in contact with 4 M monoethanolamine (MEA) and 2 M potassium taurate (PT) solution at 100°C for 250 hours. No liquid penetration through PVTMS was observed during 6 days of continuous testing at a liquid overpressure of 0.55 bar. Storing of PVTMS at 100°C in contact with air for a period of 3 months did not lead to dramatic changes in membrane gas permeability. Membrane gas desorption experiments showed that degradation of loaded MEA leads to membrane fouling, resulting in a decline of membrane performance within 6 days. However, membrane gas desorption experiments with loaded potassium taurate solution did not lead to any noticeable changes of the membrane, and, hence, stable performance of the PVTMS based membrane was observed. Comparing a porous PTFE membrane with an asymmetric PVTMS with dense selective layer shows that the solvent evaporation is at least a factor of 20 lower for the PVTMS membrane; while both porous and non-porous membranes exhibit comparable CO2 flux indicating that overall resistance of desorption process is mainly governed by the reverse chemical reactions and mass-transfer resistance in the liquid phase. © 2015 Pleiades Publishing, Ltd.
The method of periodically doped channel was originally regarded as an application for transistor structures based on organic semiconductors. The possibility of channel conductivity modulation in CMOS transistors, however, is of high interest for high temperature electronics. To provide high conductivity of the nanoregions that reduce the overall effective length of the channel due to the geometric factor a the dope density in them must be high. However, the lateral drift of dope may result in closing of the doped nanoregions and in degradation of the subthreshold characteristics of the transistor. To handle this, as a dope additive (for the N channel of the MOS transistor), it is reasonable to use arsenic with its subsequent activation by rapid thermal annealing (RTA). Using programs for process simulation, we construct the device-technological model of a periodically doped channel field-effect transistor (PDCFET). This model allows one to solve the problem of technological implementation and characterization of the transitions manufactured in a 0.18–0.5 μm process with gate regions based on nanomasks which operate under extreme thermal conditions. © Pleiades Publishing, Ltd., 2015.
Analog ICs are widely used in communication, sense and power systems of spacecraft. They are produced with variety of technologies (CMOS, BiCMOS, functional options). This paper provides TID degradation analysis for most common analog ICs - operational amplifiers, voltage comparators and linear stabilizers. General trends in radiation behavior and recommendations for analog IC's radiation testing are presented.
Analysis of flight data from spectrometers in geostationary and polar orbits is presented. Flight data are compared with other in-flight measurements and with trapped and solar particles models including AX8, AX9, CRRESELE, JPL, Nymmik. © 2015 IEEE.
this paper presents SEE test results of 256k RAM with preliminary γ-ray irradiation and comparison with previous not irradiated samples tests. Difference between irradiated and not irradiated samples test results for SEL is shown. © 2015 IEEE.
It is known that electronic properties of a quantum dot (QD) depend on its size and shape. Spectrum of emission light of a QD is changed by tuning their core diameter. For example, the cadmium selenite (CdSe) QDs emit blue light when the diameter of the core is 2nm and emit red light when it is 7 nm . Because of it QDs have a good potential for using in different light emitting devices including organic light emitting diodes (OLEDs). For example, QDs gives a good opportunity for design white OLEDs etc.
In this work we study dielectric properties of an artificial periodic structure on the base of the local field theory. We generalize Clausius-Mossotti relation for periodic structures and demonstrate that in this case a spatial dispersion of dielectric permittivity takes place.
The time evolution of the water–disordered nanoporous medium Libersorb 23 (L23) system has been studied after complete filling at elevated pressure followed by full release of overpressure. It is established that relaxation of the L23 rapidly flows out during the overpressure relief time, following the variation in pressure. At a temperature below that of the dispersion transition (T < Td = 284 K), e.g., at T = 277 K, the degree of filling θ decreases from 1 to 0.8 within 10 s. The degree of filling varies with time according to the power law θ ~ tsup–α/sup with the exponent α < 0.1 over a period of t ~ 10sup5/sup s. This process corresponds to slow relaxation of a metastable state of a nonwetting liquid in a porous medium. At times t > 10sup5/sup s, the metastable state exhibits decay, manifested as the transition to a power dependence of θ(t) with a larger exponent. The relaxation of the metastable state of nonwetting liquid in a disordered porous medium is described in the mean field approximation as a continuous sequence of metastable states with a barrier decreasing upon a decrease in the degree of filling. Using this approach, it is possible to qualitatively explain the observed relaxation process and crossover transition to the stage described by θ(t) with a larger exponent. © 2015, Pleiades Publishing, Inc.
A new approach to the design of gain blocks (such as preamps, shapers) is described. The generalized block diagram and analytic expressions for its transfer function are presented. The particular cases of this structure are classical schemes, using either the voltage or current feedback, but not confined by them. The discussed formulas can be useful for the design of a whole range of amplifier blocks, built according to both the traditional and non-traditional structures. As result of an expression analysis the features of various particular cases are given. For example, those were confirmed by simulations and experimental data. © 2015 IOP Publishing Ltd and Sissa Medialab srl.
A new approach to the design of gain blocks (such as preamps, shapers) is described. The generalized block diagram and analytic expressions for its transfer function are presented. The particular cases of this structure are classical schemes, using either the voltage or current feedback, but not confined by them. The discussed formulas can be useful for the design of a whole range of amplifier blocks, built according to both the traditional and non-traditional structures. As result of an expression analysis the features of various particular cases are given. For example, those were confirmed by simulations and experimental data.
Problems of optimizing of the power consumption of a CMOS charge-sensitive amplifier for reading out the signals of multichannel silicon and gas detectors with capacitances up to 100 pF are discussed. In multichannel systems, the power consumption of electronics is limited. In this case it is required to achieve the optimal set of parameters of a charge-sensitive amplifier, and, in the first place, not to exceed the permissible noise and power consumption levels. The procedure for optimizing the parameters of the input transistor for reaching the minimal power consumption at the specified noise level of the charge-sensitive amplifier is described.
The article discusses the creation of automated system for I-V measurements of CMOS SOI transistor test structures based on National Instruments PXI platform. The article describes the measurement system circuit diagram and its components. Article describes measurement process, user interface and resulting current-voltage characteristic example. © 2015 IEEE.
The developed automated setup for functional and parametric control of 8-bit microcontrollers during radiation hardness tests is presented. The setup hardware is based on the NI modular instruments PXI-7841R and PXI-4110 operated under LabVIEW software. Test circuit and methods together with the user software structure and typical test results are presented. © 2015 IEEE.
The article discusses automated test complex based on the PXI devices basis for monitoring parameters and functioning of integrated opamp during radiation experiments. Need of measurements and input signals high accuracy support is specified. © 2015 IEEE.
This article describes the process of creating an automated test complex for simultaneous parameters control of several voltage regulators and DC/DC-converters under irradiation based on the National Instruments PXI family equipment. © 2015 IEEE.
This article describes the automated test facility system for parametric control of voltage supervisors before, during and after irradiation in radiation tests based on the National instruments PXI family equipment. © 2015 IEEE.
The paper analyzes the effectiveness of test algorithms of different duration during the functional control of static random access memory (SRAM) during the exposure to total ionizin dose (TID). The results of experimental research SRAM chips using an automated system based on the equipment «PXI» company National Instruments, justifying the use of the test algorithms such as 'MARCH' (long-10N). © 2015 IEEE.
This article describes the automated test complex for parametric control of power n- and p-MOSFET transistors before, during and after irradiation tests based on the National instruments PXI standard equipment. © 2015 IEEE.
Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v(2)2 and v(2)4, for charged hadrons from U + U collisions at root s(NN) = 193 GeV and Au + Au collisions at root s(NN) = 200 GeV. Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v(2)2 on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U + U collisions. We also show that v(2) vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.
Trajectories of relativistic positrons moving in the electric field of oriented crystal near its surface have been simulated. A positron beam enters the field of the crystal at a small angle to crystallographic planes. Thus, planar channeling conditions are satisfied. The miscut surface of a crystal has a specific shape of a step sequence of terraces. It has been shown that such a surface can deflect a noticeable fraction of the beam from the crystal surface by means of quasichanneling. The possibility of the experimental observation of this phenomenon has been analyzed.
The motion of relativistic nuclei which move near to a crystal surface was considered. The nuclei within a beam penetrate the crystal field at the small angle to the crystallographic planes, so the average field approximation and channeling phenomenology are valid. The crystal surface has a specific terrace-like form. It was shown the significant beam fraction could be deflected outwards from the surface due to quasichanneling. (C) 2015 Elsevier B.V. All rights reserved.
This paper describes simulation methods of the radiation reliability of the performance of digital large-scale integrated circuits based on fuzzy digital Brauer automata and topological probabilistic models of performance evaluation.
The local hopping step of the electron transfer (ET) reaction is investigated for a real organic material composed of molecules M (N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine). This material is implemented in light-emitting photoelectronic devices. The conductivity effect is simulated and calculated at a molecular level. We have studied the ET mechanism alternative to that suggested by the usually employed Marcus-like polaron model. The ion-molecular binary complex Msup+/supM (for hole transfer) is considered as a reaction center. The reaction dynamics is carried through the low-frequency intermolecular vibration coordinate connecting its fragments (the promotion mode). Its coupling to the acoustic phonon bath serves for a dissipation of the reaction energy misfit. The high-frequency intramolecular vibrations (the reorganization modes) modulate the reaction kinetics via Franck-Condon factors induced by their polarization. The ET rate constants are evaluated in terms of the computational algorithm described earlier (Basilevsky, M. V.; et al. J. Chem. Phys. 2013 139, 234102). Standard quantum-chemical and molecular dynamical techniques are used for a calculation of all necessary parameters of this model. The macroscopic charge-carrier mobility of the material is estimated by properly averaging the rate constants over the total simulation cell. © 2015 American Chemical Society.
We present results of analyses of two-pion interferometry in Au+Au collisions at sNN=7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the BNL Relativistic Heavy Ion Collider Beam Energy Scan program. The extracted correlation lengths (Hanbury-Brown-Twiss radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model. © 2015 American Physical Society.
Abstract The general question of the existence of macrofluctuations of physical characteristics of aqueous systems are discussed. Using the example of analyzing fluctuations in the Rayleigh scattering of natural untreated water, along with catholyte and anolyte obtained in its electrochemical treatment, the possibility of obtaining of quantitative information on the states and dynamics of changes in such systems is shown. Data on the parameters of oscillations in the Rayleigh light scattering of water catholyte and anolyte immediately after electrolysis, and one and two days after its completion, are presented. Calculations are performed using the general phenomenological approach to analyzing chaotic signals (flicker-noise spectroscopy). Quantitative characteristics that reveal substantial differences in the dynamics of macrofluctuations that develop in the catholyte and anolyte of the studied water are presented. © 2015 Pleiades Publishing, Ltd.
Application-specific integrated circuit (ASIC), which has 10 channels containing 10-bit analog-to-digital converter (ADC) in each channel, buffer memory and a precision voltage reference, is presented. It features very low power consumption, which is less than 0.5 mW per channel at the sampling frequency of 100 kHz. ASIC focuses on the use in battery-powered devices. It was designed to use along with analog front-end ASIC for readout and A/D conversion of the signals of silicon photomultiplier (SiPM) arrays. It can also be used in other portable instrumentation and communication equipment. ASIC has been manufactured in 0.35 um CMOS process. © 2015 IEEE.
An application specific integrated circuit (ASIC), consisting of nine basic channels and one auxiliary channel, each containing a 10-bit successive-approximation analog-to-digital converter (ADC), is designed and tested. The microcircuit also includes a buffer storage unit and a reference-voltage source. The microcircuit is intended for converting signals of silicon photomultiplier arrays. To decrease the differential nonlinearity of the ADC without recourse to autocalibration, a new method, based on introducing additional elements into the layout of ADC capacitor arrays, is proposed. The basic feature of the designed microcircuit, which is oriented at the application in the portable equipment with a self-contained power supply, is the low power consumption, which does not exceed 0.5 mW per channel at a sample frequency of 150 kHz. © 2015, Pleiades Publishing, Inc.
We have developed a method for complementing an arbitrary classical dynamical system to a quantum system using the Lorenz and Rossler systems as examples. The Schrodinger equation for the corresponding quantum statistical ensemble is described in terms of the Hamilton-Jacobi formalism. We consider both the original dynamical system in the position space and the conjugate dynamical system corresponding to the momentum space. Such simultaneous consideration of mutually complementary position and momentum frameworks provides a deeper understanding of the nature of chaotic behavior in dynamical systems. We have shown that the new formalism provides a significant simplification of the Lyapunov exponents calculations. From the point of view of quantum optics, the Lorenz and Rossler systems correspond to three modes of a quantized electromagnetic field in a medium with cubic nonlinearity. From the computational point of view, the new formalism provides a basis for the analysis of complex dynamical systems using quantum computers.
A method for numerical calculation of the sound wave damping and dispersion law in a strong centrifugal field of the order of 106 g is considered. The damping is defined from the width of the resonance peak for different wave vectors. In the strong centrifugal field damping of the sound waves essentially exceeds the damping in the quiescent gas. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
An analytical equation defining separative power of an optimized concurrent gas centrifuge is obtained for an arbitrary binary mixture of isotopes. In the case of the uranium isotopes the equation gives δU= 12.7(V/700 m/s)2(300 K/T )L, kg SWU/yr, where L and V are the length and linear velocity of the rotor of the gas centrifuge, T is the temperature. This formula well agrees with an empirical separative power of counter current gas centrifuges. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
2D axisymmetric transient flow induced by a pulsed braking force in the Iguasu gas centrifuge was simulated numerically. The computational domain consists of three cameras: top, working and bottom. The feed flow injected to the working camera, product and waste fluxes removed in the bottom and top cameras, respectively. The transient case is compared with the stationary case where the flow is excited by the stationery braking force. The braking forces averaged over the period of the rotation are equal each other in both cases. In the transient case the gas flux through the gap in the bottom baffle 15 % exceeds the flux in the stationary case for the same pressure and temperature. We argued that the waves reduce the pressure in the GC on the same 15 %. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Rhie–Chow interpolation formulas are derived from the Navier–Stokes and continuity equations. These formulas are generalized to gas dynamics in strong centrifugal fields (as high as 10sup6/sup g) occurring in gas centrifuges. © 2015, Pleiades Publishing, Ltd.
Dynamics of waves generated by scopes in gas centrifuges (GC) for isotope separation is considered. The centrifugal acceleration in the GC reaches values of the order of 106g. The centrifugal and Coriolis forces modify essentially the conventional sound waves. Three families of the waves with different polarization and dispersion exist in these conditions. Dynamics of the flow in the model GC Iguasu is investigated numerically. Comparison of the results of the numerical modeling of the wave dynamics with the analytical predictions is performed. New phenomena of the resonances in the GC is found. The resonances occur for the waves polarized along the rotational axis having the smallest dumping due to the viscosity. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Linear waves are investigated in a rotating gas under the condition of strong centrifugal acceleration of the order 106g realized in gas centrifuges for separation of uranium isotopes. Sound waves split into three families of the waves under these conditions. Dispersion equations are obtained. The characteristics of the waves strongly differ from the conventional sound waves on polarization, velocity of propagation and distribution of energy of the waves in space for two families having frequencies above and below the frequency of the conventional sound waves. The energy of these waves is localized in rarefied region of the gas. The waves of the third family were not specified before. They propagate exactly along the rotational axis with the conventional sound velocity. These waves are polarized only along the rotational axis. Radial and azimuthal motions are not excited. Energy of the waves is concentrated near the wall of the rotor where the density of the gas is largest.
Dynamics of waves generated by scopes in gas centrifuges (GC) for isotope separation is considered. The centrifugal acceleration in the GC reaches values of the order of 10(6)g. The centrifugal and Coriolis forces modify essentially the conventional sound waves. Three families of the waves with different polarisation and dispersion exist in these conditions. Dynamics of the flow in the model GC Iguasu is investigated numerically. Comparison of the results of the numerical modelling of the wave dynamics with the analytical predictions is performed. New phenomena of the resonances in the GC is found. The resonances occur for the waves polarized along the rotational axis having the smallest dumping due to the viscosity.
We propose an approach that permits constructing an analytical solution of the problem of flow and heat transfer in a viscous compressible conducting medium near an infinite dielectric disk rotating in a homogeneous magnetic field. The influence of the magnetic field on the process of heat transfer near the disk surface has been investigated. It has been shown that Joule energy dissipation prevails over viscous dissipation at moderate magnetic fields. © 2015 Springer Science+Business Media New York
This work addresses the development of energy-saving (low-cost) pervaporation approach for the recovery of biobutanol from the ABE fermentation broth. To achieve this goal, thermopervaporation (TPV) separation of dilute aqueous solutions of 1-butanol through the hydrophobic poly(1-trimethylsilyl-1-propyne) (PTMSP) membranes in the plate-and-frame module with an air gap was investigated. The TPV approach allows separation at atmospheric pressure and in the presence of noncondensing gases of ABE fermentation (carbon dioxide and hydrogen). Different process parameters such as the air gap width, the temperature of the feed mixture, the permeate condensation temperature, and the membrane thickness were studied. The width of the air gap between the membrane and the condensation surface (the cooling plate) should not be lower than 2.5 mm. The TPV mode of separation of water/butanol mixture using self-supported PTMSP dense membranes makes it possible to Achieve the following process performance: the permeate flux exceeds 0.5 kg/(m(2) h) (membrane thickness is 16 gm) and the separation factor for the butanol/water mixture is about 120 (membrane thickness is 115 gm) at the atmospheric pressure and at a condensation temperature of 10 degrees C. 2015 Elsevier B.V. All rights reserved.
The relaxation of a confined nonwetting liquid dispersed in a disordered nanoporous medium has been experimentally studied in the system consisting of water and the L23 hydrophobized silica gel. It has been found that the relaxation of the system under study is anomalously slow, according to an inverse power law with the exponent a 0.16 At has been also established that the exponent in this law in the temperature range under investigation has a maximum, which can indicate a transition from the regime of the accelerated decay of a quasi-nonergodic state with an increase in the temperature to the regime of the decay of a nonergodic state with its slowing down because of the breaking of paths for the escape of the liquid through the fractal percolation cluster. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
A homogenization procedure was implemented to carry out a multiscale asymptotic analysis of Brinkman's filtration of fluid in rigid porous media. As a result we obtained averaged macroscopic equations with the components of the effective permeability tensor as effective coefficients. The derivation of the components of the effective permeability tensor was reduced to the solution of periodic boundary problems in a unit cell. In order to solve this problem we have developed an analytical-numerical method based on approximation of the solution by the series of shape functions that exactly satisfied the interface conditions on the boundaries between different phases of flow. For some specific elements of a periodic pore structure, the shape functions can be obtained in a closed analytical form. This enables ones to monitor the accuracy of the cell problem solution. We have solved the cell problem in 1D and 3D formulations and provided a comparison of the effective permeability coefficients, computed analytically and numerically for both Brinkman's and Stokes' filtration for different cases of a microscopic pore structure. The results of the cell problem solution have been subsequently used in the integration of the averaged macroscopic equations for determining the distribution of fluid pressure and velocity. © 2015 by Begell House, Inc.
Similarity of the extrusion curves of non-wetting liquid in a nanoporous medium with different initial fill volume fractions is observed experimentally. The similarity can be explained by the scaling of the interface energy and the self-similarity of the infinite percolation cluster of fluid-filled pores. Understanding the physical processes leading to the observed phenomena is a foundation for the development of high-performance devices for damping and energy storage on the basis of such heterogeneous systems.
An approach has been proposed for the analysis of transition of a non-wetting liquid to clusters of liquid in the disordered nanoporous medium. This approach describes a novel model of randomly distributed overlapping spheres of different radii. The model allows to define the disordered porous medium with new parameters: the number of nearest neighbors and the area of all mouths that connect pore with the neighboring pores. These parameters depend on the pore size and porosity and make it possible to analytically describe the dispersion transition. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
An approach is proposed for analysis of the transition of a nonwetting liquid to clusters of liquid in the disordered nanoporous medium. This approach describes a novel model of randomly distributed overlapping spheres of different radii. The model allows us to define the disordered porous medium with new parameters: the number of nearest neighbors and the area of all mouths that connect a pore with neighboring pores. These parameters depend on the pore size and porosity and make it possible to analytically describe the dispersion transition.
This work was focused on investigation of industrial cellophane film as a membrane material for solvent nanofiltration. The effect of conditioning of cellophane membranes by stepwise changing of composition of ethanol-water binary mixtures (from ethanol to water and from water to ethanol) was studied. It was shown that such treatment leads to an increase of ethanol permeability more than two orders of magnitude over initial untreated film samples. Treated cellophane membranes possess the ethanol permeability coefficient comparable with the values for highly permeability glassy polymers. Investigation of cellophane swelling in water ethanol solutions allowed to conclude that during the treatment formation of porous in the film takes place due to increase of inter chain distances. Observed high ethanol permeability connected with the fact that formed porous structure remains after the replacement of water with ethanol. Also it was shown that rejection coefficients of a number of dyes (MW 350) were in good agreement with the degree of hydrophobicity/hydrophilicity and ability of the solvent to form hydrogen bonding with the solute molecules. It was demonstrated that cellulose-based membranes can be complimentary for other type of the membranes in fractionation of multi-components solutions. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The PHENIX experiment at RHIC has measured the centrality dependence of the direct photon yield from Au + Au collisions at root s(NN) = 200 GeV down to pT = 0.4 GeV/c. Photons are detected via photon conversions to e(+)e(-) pairs and an improved technique is applied that minimizes the systematic uncertainties that usually limit direct photon measurements, in particular at low pT. We find an excess of direct photons above the N-coll-scaled yield measured in p + p collisions. This excess yield is well described by an exponential distribution with an inverse slope of about 240 MeV/c in the pT range 0.6-2.0 GeV/c. While the shape of the pT distribution is independent of centrality within the experimental uncertainties, the yield increases rapidly with increasing centrality, scaling approximately with N-part(alpha), where alpha = 1.38 +/- 0.03(stat) +/- 0.07(syst).
We present midrapidity charged-pion invariant cross sections, the ratio of the pi(-) to pi(+) cross sections and the charge-separated double-spin asymmetries in polarized p + p collisions at root s = p + 200 GeV. While the cross section measurements are consistent within the errors of next-to-leading-order (NLO) perturbative quantum chromodynamics predictions (pQCD), the same calculations overestimate the ratio of the charged-pion cross sections. This discrepancy arises from the cancellation of the substantial systematic errors associated with the NLO-pQCD predictions in the ratio and highlights the constraints these data will place on flavor-dependent pion fragmentation functions. The charge-separated pion asymmetries presented here sample an x range of similar to 0.03-0.16 and provide unique information on the sign of the gluon-helicity distribution.
Event-by-event fluctuations of the multiplicities of inclusive charged particles and photons at forward rapidity in Au + Au collisions at root s(NN) = 200 GeV have been studied. The dominant contribution to such fluctuations is expected to come from correlated production of charged and neutral pions. We search for evidence of dynamical fluctuations of different physical origins. Observables constructed out of moments of multiplicities are used as measures of fluctuations. Mixed events and model calculations are used as base lines. Results are compared to the dynamical net-charge fluctuations measured in the same acceptance. A nonzero statistically significant signal of dynamical fluctuations is observed in excess to the model prediction when charged particles and photons are measured in the same acceptance. We find that, unlike dynamical net-charge fluctuation, charge-neutral fluctuation is not dominated by correlation owing to particle decay. Results are compared to the expectations based on the generic production mechanism of pions owing to isospin symmetry, for which no significant (1%) deviation is observed.
An approach to IC SEE sensitivity parameters estimation based on charge collection by a point node is discussed. SEE sensitivity dependences on incident angle, ion ranges and IC finite sizes are considered. © 2015 IEEE.
A new software package for visualization of atomic clusters and molecules is designed. Instead of analogous software products, this one compiled as a dynamic link library. It allows easy integration with any modeling program and "on-fly" visualization of calculated results. The software provides static and dynamic clusters and molecules visualization in atom-bond notation. Carried out tests prove the ability of new package to visualize a wide range of atomic clusters and nanostructures, included large biological macromolecules.
If target deuterium atoms were implanted in a metal crystal in accelerator experiments, a sharp increase in the probability of DD-fusion reaction was clearly observed when compared with the reaction's theoretical value. The electronic screening potential, which for a collision of free deuterium atoms is about 27eV, reached 300-700eV in the case of the DD-fusion in metallic crystals. These data leads to the conclusion that a ban must exist for deuterium atoms to be in the ground state 1s in a niche filled with free conduction electrons. At the same time, the state 2p whose energy level is only 10eV above that of state 1s is allowed in these conditions. With anisotropy of 2p, 3p or above orbitals, their spatial positions are strictly determined in the lattice coordinate system. When filling out the same potential niches with two deuterium atoms in the states 2p, 3p or higher, the nuclei of these atoms can be permanently positioned without creating much Coulomb repulsion at a very short distance from each other. In this case, the transparency of the potential barrier increases dramatically compared to the ground state 1s for these atoms. The probability of the deuterium nuclei penetrating the Coulomb barrier by zero quantum vibration of the DD-system also increases dramatically. The so-called cold nuclear DD-fusion for a number of years was registered in many experiments, however, was still rejected by mainstream science for allegedly having no consistent scientific explanation. Finally, it received the validation. Below, we outline the concept of this explanation and give the necessary calculations. This paper also considers the further destiny of the formed intermediate state of 4He*.
Bent silicon crystals in channeling mode are already used for beam extraction and collimation in particle accelerators. Volume reflection of beam particles is more efficient than beam channeling; however, the mean deflection angle is rather small. An experiment on the deflection of a 400 GeV/c proton beam and a 150 GeV/c πsup−/sup beam at CERN using a multi-strip silicon deflector in reflection mode is described. The mean deflection angle of beam particles has been considerably increased due to sequential volume reflections realized in the deflector. This gives possibility for a successful usage of the multi-strip deflectors for beam collimation in high-energy accelerators. © 2015, Pleiades Publishing, Inc.
Abstract Supersonic nozzle is a key component of a gas cluster condensation system. We describe a flow visualization system using glow discharge with annular or plane electrodes. The geometric parameters of a supersonic jet under typical conditions used in a gas cluster ion beam accelerator are investigated. As well numerical simulations were performed. Dependence of inlet and ambient pressures and nozzle throat diameter on the shock bottle dimensions is described for different working gases. Influence of condensation rate on shock bottle axial size is discussed. © 2015 Elsevier B.V.
The percolation threshold and wrapping probability (R ∞) for the two-dimensional problem of continuum percolation on the surface of a Klein bottle have been calculated by the Monte Carlo method with the Newman-Ziff algorithm for completely permeable disks. It has been shown that the percolation threshold of disks on the Klein bottle coincides with the percolation threshold of disks on the surface of a torus, indicating that this threshold is topologically invariant. The scaling exponents determining corrections to the wrapping probability and critical concentration owing to the finite-size effects are also topologically invariant. At the same time, the quantities R ∞ are different for percolation on the torus and Klein bottle and are apparently determined by the topology of the surface. Furthermore, the difference between the R ∞ values for the torus and Klein bottle means that at least one of the percolation clusters is degenerate. © 2015 IOP Publishing Ltd.
Simulation of radiation from a channel with variable radius in the THz region is performed using Particle In Cell (PIC) solver of the Computer Simulation Technology (CST) software package. Simulation results are compared with theoretical expressions, similarities and differences between theoretical model and computer simulation are discussed. © 2015 Elsevier B.V.
Cherenkov Smith - Purcell radiation (SPR) from a corrugated channel in infinite dielectric material is simulated and compared with a theoretical investigation for such geometry. Dependencies of Cherenkov and SPR intensities on the corrugation depth and the internal radius of the channel are discussed. A corrugated capillary with partial metal coating is also considered in the simulations in order to obtain optimal values of the corrugation depth and the external radius of the capillary. Copyright © 2015 CC-BY-3.0 and by the respective authors.
Smith-Purcell radiation (SPR) from a lamellar grating with vacuum gaps was calculated using Computer Simulation Technology (CST) Particle In Cell (PIC) solver. The shapes of the radiation distributions were compared with those of Resonant Diffraction Radiation theory. Study of calculation domain meshing was performed. Influence of a transverse bunch size on the calculation accuracy and an SPR intensity distribution was investigated. Dependencies of the SPR yield on Lorentz factor and grating strip depth were calculated and compared with previously reported theoretical and experimental studies. (C) 2015 Elsevier B.V. All rights reserved.
The interaction of high energy gamma-quanta with crystal surfaces under small sliding angles is considered. It is shown that under certain conditions, such interactions can be described in classical wave theory formalism up to the energies, exceeding 10(11) eV. (C) 2015 Elsevier B.V. All rights reserved.
Data processing characteristics can significantly affect reliability of obtained results. Here we discuss two recently developed data collection instruments based on analog-to-digital converters. The first instrument is based on three 500 MHz 12 bit ADC and used for extended dynamic range measurements. Based on 667 MHz 8 bit ADC the second one allows fast 3D data acquisition. The instruments were used for time-of-flight mass spectrometry and ion mobility TOF mass spectrometry fast data acquisition and processing. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The usual and effective way to increase on-board electronics reliability and general radiation hardness is the usage of "sleeping" (shutdown) mode and "passive" reserve of vulnerable blocks and elements. This work presents the comparative radiation test results of hybrid and integrated DC-DC converter's TID's sensitivity in active, sleeping and passive modes. The obtained experimental data demonstrates that TID hardness of bipolar, BiCMOS and hybrid DC-DCs in the unbiased condition is at least not higher than their normally biased mode. Moreover some of bipolar integrated DC-DCs have relatively higher radiation-induced degradation while unbiased, so their "passive" (so-called "cold") reserve mode may be the worst case mode for TID's hardness level. © 2015 Elsevier Ltd.
6T SRAM bitcells for high density 64MB SRAM has been designed. Test chip with memory arrays based on these bitcells was manufactured and characterized for radiation effects. The device is SEL immune, has an error rate less than 4E-18 errors/bit•day. © 2015 IEEE.
A method to produce relatively high concentrations of intermediate components from isotope mixtures in a separation cascade with local extension of a working substance flow at its inner stages is demonstrated. The cascade under consideration consists of two square parts of different width and has 4 external flows: the feed and waste ones and the end and interjacent product flows. The research demonstrates that the cascade with flow extension built by simple reshaping of a square cascade enables provide considerable increasing an intermediate component concentration in an interjacent product flow in comparison with the conventional 4 flows square cascade having the same values of the total and additional flows. In the example, it was examined enrichment of the W-183 isotope for which an increase in concentration provided by a cascade with flow extension is about 5 abs% whereas the compared cascades keep at their end product flows almost the same concentration of separating components. (c) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Possibilities of gridless ion mirror usage in conjunction with laser ion source were studied in this paper. This was done in order to get time focusing by energies of ions. Mirror voltages were adjusted so that time focusing by energies of 6th was achieved. This means reduction of time aberrations down to 1 ns. Such a time focusing can be applied to ions with energy spread up to ±20%. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Early diagnostics of meningitis is a very topical problem as it is a fulminant disease with a high level of mortality. The progress of this disease is, as a rule, accompanied by the appearance of bacteria in the cerebrospinal fluid (CSF) composition. The examination of the CSF is well known to be the only reliable approach to the identification of meningitis. However, the traditional biochemical analyses are time consuming and not always reliable, simple, and inexpensive, whereas the optical methods are poorly developed. This work is devoted to the study of Raman spectra of several bacterial cultures which are mainly present during meningitis. Raman microscopy is a prompt and noninvasive technique capable of providing reliable information about molecular-level alterations of biological objects at their minimal quantity and size. It was shown that there are characteristic lines in Raman spectra which can be the reliable markers for determination of bacterial form of meningitis at a level of a single bacterium. © Published under licence by IOP Publishing Ltd.
Different approaches to water purification are considered. It is shown that for developing of effective purification methods in the different water treatment technologies special knowledge is necessary. This knowledge deals with physical-chemical processes of used reagents interaction with contaminating impurities. The obtaining of the necessary data on physics-chemical processes such as the formation of chemical compounds of iron, the change in valence state of iron, adsorption and absorption pollutants are analyzed. The usage of iron compounds as a cleaners and the water treatment from the iron pollutant are the events, in which Mössbauer spectroscopy allows to determine not only the chemical changes, but also to obtain quantitative data on the reaction products and on the sizes of reaction products and their quantities. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The Russian Emission Detector 100 (RED-100) under construction at the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) is designed to detect the presently undiscovered effect of coherent neutrino scattering. One of the factors limiting the sensitivity of the detector is the spontaneous decay of uranium and thorium in the detector materials. Radioactive impurities in detector materials at levels of parts per billion can significantly affect the sensitivity. Five random samples of titanium and one of copper-from materials used in the construction of the detector were selected for assay. The concentrations of Th-232 and U-238 were measured by inductively coupled plasma mass spectrometry (ICP-MS) in solid titanium using both solutions in acids and direct sampling by laser ablation (LA-ICP-MS). The LA-ICP-MS method allowed us to determine U-238 and Th-232 at subnanogram per gram levels. This method is much faster than ICP-MS with liquid injection. The titanium samples studied have impurities in the range between 1 ng g(-1) and 21 ng g(-1) for U-238 and 3 ng g(-1) and 31 ng g(-1) for Th-232. In copper we set upper limits of 0.4 ng g(-1) for U-238 and 1 ng g(-1) for Th-232. The total activity of the cryostat constructed from the materials studied was estimated to be 43 Bq.
The problems of deuteron extraction from the plasma of a vacuum arc were examined. The experimental dependence of the deuterons yield on the voltage of the pulse was obtained. The effects of Langmuir waves in plasma on the deuteron current were shown. An expression for the deuteron current from pulsed plasma source was obtained. © 2015 The Authors.
The STAR Collaboration presents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au. +. Au and minimum-bias d. +. Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au. +. Au data with respect to the d. +. Au reference and the absence of such an enhancement for leading non-pions (protons and kaons) are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region, is found to be significantly higher for leading non-pions than pions. The consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization. © 2015 The Authors.
Four parts of opamp OP1177ARZ manufactured by Analog Devices have been tested. The chips have been compared visually and with specialized software. Forms of ionization response in three checkpoints have been registered, and maps of response amplitudes on the crystal surface have been constructed. It has been determined , that crystals samples are various in spite of identical crystals marking. So TID behavior of various samples has been observed. © 2015 IEEE.
In this paper, we present development of digital intellectual sensors (DIS) for gas sensor applications based on open digital data exchange protocol using National Standard of Russian Federation for intelligent gas sensor modules. For demonstration possibilities of intellectual sensors in paper described electronic digital driver for oxygen electrochemical gas sensor. In this work a lot of attention gave to questions of standardization and unification for creation a commercially available system for gas analytical instruments industry. © 2015 IEEE.
In this article a new analytical description of the effective interaction potential for a charged particle with the field of two interfering laser beams is presented. The potential dependence on the lasers intensities, orientation and parameters of the particle entering the considered system is analyzed. For the first time the phenomenon of effective potential inversion (or "relativistic reversal") is described for arbitrary lasers crossing angle. Threshold electron velocity values for the phenomenon are introduced and its extended illustration based on numerical simulations for two laser beams polarizations is presented. In addition the projectile radiation spectral distribution is given and general estimations on the expected beam radiation yield are outlined.
A dispersion transition in the Fluka 100 C8 and Fluka 100 CI8 hydrophobic silica gels close in the structural characteristics has been studied. Nonlinear dependences of the volume of the trapped liquid on the degree of filling, which have not yet been observed at the interaction of nonwetting liquids with nanoporous media, have been revealed. Two critical temperatures Tcl ≈ 330 K and Tc2 ≈ 340 K have been found for the Fluka 100 C18/water system. At a temperature above Tcl, a transition occurs at a degree of filling of 0.5 from the state of the system with a linear increase in the volume of the trapped liquid with the degree of filling to the state in which the dispersion transition occurs at a degree of filling of 0.5. At temperatures above Tc2, the fraction of the trapped liquid is small and independent of the temperature and degree of filling. When Fluka 100 C8 is filled with water, no abrupt change in the volume of the trapped liquid with an increase in the degree of filling has been detected in the temperature range under study T= 300-360 K. In this case, a linear increase in the volume of the trapped liquid with the degree of filling has been observed. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Dissociation of trinitrotoluene (TNT) sorbed on porous silicon (pSi) surface under UV laser irradiation has been studied. A method based on ion mobility spectrometry (IMS) has been used in this study. Excitation and ionization of TNT molecules has been occurred at atmospheric pressure. A dependence of TNT ion spectrum on standing time of TNT molecules on pSi surface has been demonstrated. The ion type has changed from (TNT-H) - to (TNT-NO2) - which indicates a slow chemical reaction between pSi surface and TNT molecules. The first step of (TNT-NO2) - formation has been found to be a result of laser stimulated surface dissociation and subsequent desorption of a neutral TNT-NO2 fragment. The second step of (TNT-NO2) - formation is a capture of an electron emitted from the pSi surface under laser irradiation. The result of this study could be used in the area of explosive detection. © 2015 The Authors.
The impact of diamond and graphene heat spreading layers on the thermal and electrical characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) has been investigated using numerical simulations in the hydrodynamic model. It is shown that the introduction of heat spreader significantly reduced maximum device temperature, increased the device lifetime, and improved current-voltage characteristics. The conditions under which the heat spreader works most effectively were found. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Dihadron correlations are analyzed in √sNN = 200 GeV d + Au collisions classified by forward charged particle multiplicity and zero-degree neutral energy in the Au-beam direction. It is found that the jetlike correlated yield increases with the event multiplicity. After taking into account this dependence, the non-jet contribution on the away side is minimal, leaving little room for a back-to-back ridge in these collisions. © 2015 The Authors.
The organic ligands passivating the surface of semiconductor quantum dots (QDs) and the solvents used strongly determine the photostability of QD solutions. Highly purified QD solutions in chloroform have been shown to photodegrade upon pulsed ultraviolet (UV) irradiation, irrespectively of the type of surface ligand. However, the photostability of QDs dissolved in n-octane, a more photochemically inert solvent, strongly depends on the ligands passivating their surface. In n-octane, hexadecylamine-coated QDs are completely stable and display no photochemical response to pulsed UV laser irradiation. In solutions of octanethiol-capped QDs, the photoluminescence intensity slightly decreases under irradiation. QDs coated with trioctylphosphine oxide exhibit a more complex pattern of photobleaching, which depends on the initial value of fluorescence quantum yield of QDs. This complex pattern may be accounted for by two competing processes: (1) ligand photodesorption accompanied by photobleaching due to specific alignment of the band levels of QDs and highest occupied molecular orbital of the ligand and (2) photoinduced decrease in the population of trapping states. Furthermore, practically no thermodynamic degradation of QD solutions has been observed for the micromolar QD concentration used in the study, in contrast to lower concentrations, thus confirming the photoinduced origin of the changes caused by UV irradiation. Obtained results show that the photostability of QDs may be strongly increased by careful selection of the ligands passivating their surface and the solvents used in the experiments.
Methods of determination of effective mechanical properties of unidirectional fiber composites are discussed. These are mixture rule, Halpin-Tsai and Hashin-Rosen methods. Comparison of analytical calculations of the mechanical characteristics of the composites with numerical results obtained by the SYSPLY package are used to specify analytic equations defining the characteristics in frameworks of each method. The field of application of each method is discussed. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The influence of the electric operating regime of hybrid pulse DC-DC converters on the number of single event transient and, consequently, the sensetive parameters is analyzed. The predicted dependence of the single-effect characteristic in hybrid stabilizers on the electric regime in general and the feedback performance in particular is confirmed experimentally. The recommendations for carrying out the certification tests for the sensetive of hybrid voltage stabilizers to single effects are outlined.
The electrophysical and structural properties of InAlAs/InGaAs/InAlAs quantum wells (QWs) with thin InAs inserts were investigated by means of Hall effect measurements and scanning transmission electron microscopy. The analyzed heterostructures are nearly the same ones using for high electron mobility transistors manufacturing except for heavily doped contact top layer. The increase of the electron mobility and concentration in the heterostructures with thin InAs layers in the center of the InGaAs QW as compared with the uniform QW was found and this effect strongly depended on the technological conditions during growth of the InAs inserts. The dependence of the InAs insert structural quality and heterointerface width on the Asinf4/inf beam equivalent pressure P infAs/inf was revealed. The decreased P infAs/inf is required for obtaining uniform and smooth InAs inserts as opposed to higher P infAs/inf resulting in the interface spreading and lateral composition inhomogeneity of the InAs insert. Copyright © Materials Research Society 2015
An analytic solution to the problem of current passage via an ideal insulator in the case of monopolar hole injection has been found. The current-voltage (J-V) characteristics have been obtained for the first time in a broad range of parameters (insulator length, hole concentrations at boundaries, temperature, etc.) and applied voltages. It is shown that the Mott-Gurney quadratic J-V relation is valid only in a certain interval of currents between J1 and J2. For J < J1, the current linearly depends on voltage V to within V3 terms. A new mode has been found for J > J2, where the J-V characteristic also becomes linear because the insulator is completely filled with injected holes. The integration constants are determined in the entire range of parameters and currents. Analytic expressions for the spatial electric-field and hole-concentration distributions are derived.
The acceptance-corrected dielectron excess mass spectra, where the known hadronic sources have been subtracted from the inclusive dielectron mass spectra, are reported for the first time at mid-rapidity |yee|<1 in minimum-bias Au+Au collisions at √sNN=19.6 and 200 GeV. The excess mass spectra are consistently described by a model calculation with a broadened ρ spectral function for Mee<1.1 GeV/c2. The integrated dielectron excess yield at √sNN=19.6 GeV for 0.4<Mee<0.75 GeV/c2, normalized to the charged particle multiplicity at mid-rapidity, has a value similar to that in In+In collisions at √sNN=17.3 GeV. For √sNN=200 GeV, the normalized excess yield in central collisions is higher than that at √sNN=17.3 GeV and increases from peripheral to central collisions. These measurements indicate that the lifetime of the hot, dense medium created in central Au+Au collisions at √sNN=200 GeV is longer than those in peripheral collisions and at lower energies. © 2015 The Authors.
A search for the quantum chromodynamics (QCD) critical point was performed by the STAR experiment at the BNL Relativistic Heavy Ion Collider, using dynamical fluctuations of unlike particle pairs. Heavy ion collisions were studied over a large range of collision energies with homogeneous acceptance and excellent particle identification, covering a significant range in the QCD phase diagram where a critical point may be located. Dynamical K pi, p pi, and Kp fluctuations as measured by the STAR experiment in central 0-5% Au + Au collisions from center-of-mass collision energies root s(NN) = 7.7 to 200 GeV are presented. The observable nu(dyn) was used to quantify the magnitude of the dynamical fluctuations in event-by-event measurements of the Kp, pp, and Kp pairs. The energy dependences of these fluctuations from central 0-5% Au + Au collisions all demonstrate a smooth evolution with collision energy.
In this work we present the results of the resonance energy transfer study in bio-nanohybrid structures, engineered on the basis of semiconductor quantum dots (QD) and photosensitive membrane protein bacteriorhodopsin (bR) in purple membranes (PM) under one- and two-photon excitation. We showed the formation of bio-nanohybrid complexes between QDs and PMs and we also showed the Forster resonance energy transfer (FRET) from QDs to bR under one-photon excitation. The measured two-photon absorption cross-section (TPACS) of QDs was about two orders of magnitude larger than TPACS of bR and consequently the two-photon excitation of QDs in hybrid structure is highly selective. It was found that FRET in bio-nanohybrid system of QDs and bR under two-photon excitation is possible and the FRET efficiency was sufficient to initiation of bR photocycle. Studying of energy transfer between QDs and bR gives the perspective of considerable improvement of bR light absorption and consequently extends the possible applications of this photo-converting material. Additionally we showed that the two-photon excitation of QDs in QD-bR hybrid material makes possible the initiating of bR photocycle in the infrared spectral range. © 2015 The Authors.
The target model of the NRNU MEPhI provides, in particular, the transition to the use of distance learning platforms, integrated with the international educational environment and social learning networking. A special place in education network is allocated to computer tools to support the learning process. These tools include Cyber Learning Platform for Nuclear Education and Training (CLP4NET) related to the automated monitoring systems and support of the learning process. NRNU MEPhI pays particular attention to Control and managed content (CMC), virtual labs and PC-based simulators of nuclear power plant (NPP), and especially when they are used as part of CLP4NET. © 2015 IEEE.
Hybrid systems with luminophores embedded in a matrix attract much interest in areas of sensors and photonic elements. The use of photonic crystals as the matrices allows controlling the propagation and distribution of light emitted by the luminophore, which could improve the sensitivity of sensors and performance of photonic elements. We have investigated the luminescent properties of CdSe/CdS/Zns quantum dots embedded in a porous silicon Bragg mirror using simple technique based on capillary effect. For the first time an angular dependence of the photoluminescence spectrum has been measured. We have found that luminescence spectrum has been found to depend on the shape of the Bragg mirror reflection spectrum. Enhancement of QD PL at the wavelength corresponding to the edge of the photonic band gap of the photonic crystal has been demonstrated. © 2015 The Authors.
The kinetics of agglomeration of multiwalled carbon nanotubes dispersed in chloroform has been studied by the methods of optical spectroscopy and dynamic light scattering. With the use of the models of the diffusion of cylindrical particles, the sizes of particles obtained by this method can be recalculated to the DLS data and the concentration at which the dispersion of individual MWCNTs occurs can be determined. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Parameters of a percolation cluster of cylindrical particles in the films are calculated by the Monte Carlo method. For particles of different sizes, characteristics and dimensions of the percolation cluster are modeled. It is shown that at the same concentration of particles in the films, fluctuations of the percolation cluster parameters can lead to a change in the transport characteristics of composite materials. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The Evaluation technique for radiation degradation of temperature dependences of operational amplifier input bias currents was developed. The technique can improve the accuracy of prediction of radiation hardness of operational amplifiers in full operation temperature range. © 2015 IEEE.
This work presents the results of experiments on the compression of a spherical copper shell loaded by the detonation of a plastic explosive layer. A U-70 accelerator is used for radiographic recording of the convergence of the shell to the center, and metallographic analysis of the copper shell preserved after the experiment is performed. The results of multiframe proton radiography of the convergence of the inner boundary of the copper shell to the center are compared with the results of numerical simulations. © 2015, Pleiades Publishing, Ltd.
HEMT structures with In0.53Ga0.47As quantum well are synthesized using molecular-beam epitaxy on InP substrates. The structures are double-side Si delta-doped so that two dimensionally-quantized subbands are occupied. The effect of the central InAs nanoinsert in the quantum well on the electron effective masses m* and mobilities in each subband is studied. For experimental determination of m*, the quantum mu (q) and transport mu (t) mobilities of the two-dimensional electron gas in each dimensionally-quantized subband, the Shubnikov-de Haas effect is measured at two temperatures of 4.2 and 8.4 K. The electron effective masses are determined by the temperature dependence of the oscillation amplitudes, separating the oscillations of each dimensionally-quantized subband. The Fourier spectra of oscillations are used to determine the electron mobilities mu (q) and mu (t) in each dimensionally-quantized subband. It is shown that m* decreases as the InAs-nanoinsert thickness d in the In0.53Ga0.47As quantum well and electron mobilities increase. The maximum electron mobility is observed at the insert thickness d = 3.4 nm.
The paper deals with radiation resistant sensors and their associated measuring instrumentation developed in the course of R and D activities carried out in the framework of an international collaboration. The first trial tests of three-dimensional (3D) probes with Hall sensors have been performed in European tokamaks TORE SUPRA (2004) and JET (2005). Later in 2009 six sets of 3D probes were installed in JET and now continue to operate. The statistical analysis performed in 2014 on the basis of the JET database have demonstrated stable long term operation of all 18 sensors of 3D probes. The results of measurements conducted at the neutron fluxes of nuclear reactors have demonstrated the operability of the sensors up to high neutron fluences of F > 10sup18/supn cmsup-2/sup that exceeds the maximum one for the locations of steady state sensors in ITER over its total lifetime. © 2015 EURATOM.
SEEs in SiT8003 MEMS-oscillator were investigated. Irradiation was provided with ion-cyclotron and picosecond focused laser. SEL, SEU were observed. Threshold LET, saturation cross-section were estimated. High SEE sensitivity of SiT8003 is shown. © 2015 IEEE.
The technique for experimental determination of ELRDS-free devices is described. The technique is based on the conversion model of low dose rate effect in bipolar transistors. © 2015 IEEE.
An original preparation technique of the thorium films by electrochemical deposition from thorium nitrate solution on different substrate is reported. It was found that electrochemical deposition of thorium on the metal surface provides the formation of adherent continuous films, while the deposition on the semiconductor substrates leads to the formation of thorium island films. The origin of the observed thorium films formation and the results on the investigation of thorium films on Si(111) and polycrystalline Cu surfaces by XPS and LEIS are discussed. © 2014 IEEE.
The target of this work is the demonstration of advanced approaches able to provide rapid prototyping by using laser technology ceramic MEMS platforms for chemical sensor operating under harsh environmental conditions and, on the other hand, to assure microhotplate stable at high temperature, which can be used for the deposition of high working temperature gas sensing materials, for example, oxides of tin, gallium, zirconium and hafnium. As substrate ceramic material in work using alumina oxide. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
In this paper, a method of producing the metallization on the alumina ceramic substrate by micropowders of ruthenium dioxide sintering using laser radiation with 10.6 micrometers length (carbon dioxide laser) is described. During the work parameters of the mask, allowing to reduce the width of the laser spot as well as to get a mildly sloping profile of the radiation intensity, due to which more uniform sintering of the powders and pastes based on them takes place, are calculated. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
During the topology creation by the selective laser sintering method experimental samples of microheater based on ruthenium dioxide micro-powder were made. The resulting structures were used as microheaters to measure changes in the thermal conductivity of gases. A power comparison of standard platinum spiral element widely used in catalytic thermal sensors and microheater produced by the new technology showed the advantage of the latter. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The layout of experimental samples of microhotplate based on nanocomposite material consisting of ruthenium dioxide and borosilicate glass binder were formed by selective laser sintering method. The resulting structures were used as microhotplate to measure changes in thermal conductivity of gases. The comparison of power consumption of standard platinum wire coil element widely used in thermocatalytic (calorimetric) sensors and microhotplate produced by the new technology showed strong advantage of the latter one. © 2015 The Authors. Published by Elsevier Ltd.
We present a novel approach to the fabrication of MEMS devices, which can be used for gas sensors operating in harsh environment in wireless and autonomous information systems. MEMS platforms based on ZrO2/Y2O3 (YSZ) are applied in these devices. The methods of ceramic MEMS devices fabrication with laser micromachining are considered. It is shown that the application of YSZ membranes permits a decrease in MEMS power consumption at 450°C down to ~75 mW at continuous heating and down to ~ 1 mW at pulse heating mode. The application of the platforms is not restricted by gas sensors: they can be used for fast thermometers, bolometric matrices, flowmeteres and other MEMS devices working under harsh environmental conditions. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
We demonstrate the possibility of obtaining information on small-scale inhomogeneities of the surface of a dielectric, which are caused by natural variation of the surface-layer polarizability and fluctuations of surface properties, by means of refraction of a plane electromagnetic wave under the condition of total internal reflection. © 2015, Pleiades Publishing, Ltd.
We investigate a possibility of an interference of diffraction radiation with a field, originated from scattering of refracted on a non-uniform surface electromagnetic wave in a case of total internal reflection. An effect of the field from fast charged particle and the refracted field on surface inhomogeneities gives rise to emergence of surface polarization currents. Radiation from these currents can be of use in analysis of surface optical features. The opportunity of studying of surface characteristics by means of diffraction radiation and total internal reflection of the electromagnetic wave is discussed in this paper. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
In this work we consider an effect of surface inhomogeneities of left-handed materials on light reflection and refraction. It is shown that total internal reflection could be useful for investigation of surface optical characteristics of metamaterial. Scattering of refracted wave in the near-surface layer leads to existence of radiation propagating from the boundary to the point of observation. The angular distribution of the resulting radiation is derived and the opportunity of getting information about optical properties of metamaterial surface with help of this method is discussed.
The influence of treatment with streams of high-temperature pulsed plasma on the phase composition of 20KhGNM steel is investigated via scanning electron spectroscopy and Mössbauer spectroscopy. It is demonstrated that a submicrocrystalline cell structure is formed on surface under irradiation. A magnetic phase and a paramagnetic austenitic phase formed after plasma treatment are observed. © 2015, Allerton Press, Inc.
Hopping transport of charge carriers in thin ( 100 nm) organic layers is modeled, using Gaussian disorder model. Monte-Carlo simulations yield considerable decrease of drift mobility with thickness of the layer, which is in good agreement with the developed analytic model. The reason is that filling of rare deep states is statistically improbable in course of transient across a thin sample. Quasi-equilibrium initial distribution is considered to omit effects of dispersive transport. Results of the work can explain disagreement in results of non-stationary and stationary measurements of transport coefficients in thin films. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
An original technology for the controllable formation of the catalytically active functional electrode nanocomposites based on porous silicon (PS) with platinum nanoparticles has been proposed. The nanocomposites are studied by electron microscopy and cyclic voltammetry methods. The synthesized materials have demonstrated high electrocatalytic properties in the reactions of oxygen electroreduction and hydrogen oxidation © 2015, Pleiades Publishing, Ltd.
In this work based on channeling phenomenon the problem of electron beam deflection by plane averaged potential formed by two crossed lasers is described. The effective potential formed at grazing reflection of laser field from curved conducting surface is derived. The critical radius for electron steering in such a system as well as the conditions for effective beam reflection are introduced. © 2015.
A model cascade is usually created before constructing a practical isotope separation cascade as the target for approximating a practical cascade. The Q-cascade is a widely used model cascade for continuous profiles in separating multi-component isotope mixtures. The optimization of a Q-cascade with specified concentrations for a target component in the product and waste flows can be conveniently performed by adjusting the mass number (M) of a virtual component. In previous studies, the M parameter was treated as identical throughout the entire cascade. This paper proposes further optimization of a Q-cascade by splitting the cascade into segments and allowing each segment to take a different value for M. An example is presented for separating Cd isotopes; the numerical results demonstrated that segmented Q-cascades achieved better separation performance than traditional Q-cascades. © 2015 The Institution of Chemical Engineers.
Mixed matrix membranes (MMMs) with unique transport characteristics can be prepared by the addition of the minor amounts of carbon nanotubes. Changes in the membrane performance are shown to be provided by the formation of a percolation cluster composed of nanotubes. For MMMs based on poly(trimethylvinylsilane) (PVTMS) containing carbon nanotubes (CNT), due to the formation of the CNT percolation cluster, gas permeability increases by a factor of 5-15. Numerical simulation proves that the above negative changes are provided by the agglomeration of nanotubes and subsequent deterioration of the percolation structure in the membranes. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
A X-ray ?-tomography technique, using a Cu K? source at 8.048. keV coupled with both polycapillary optics and CCD detector, has been developed to reconstruct the composition of a transient gasoline spray generated by a high-pressure GDI injector for automotive applications. The polycapillary elements enable shaping the divergent beams and getting high-contrast images due to the suppression of radiation multiple scattering. A pressure-tight device permits the 360° rotation of a six-hole nozzle, with a step of 0.1°, at injection pressures up to 20. MPa, while the spray plume develops in a vented Plexiglas chamber at the atmospheric backpressure. The entire system is configured as a table-top experiment. The extinction images acquired along the X-ray source-spray-detector line-of-sight have permitted the reconstruction of a 3D structure together with a morphology of the jets within a 3. mm region downstream the nozzle. The spray shape as well as the propagation direction can be clearly identified in the tomographic reconstruction for all the six jets. Quantitative measurements of the fuel mass density in the near nozzle region have been performed. Typical Gaussian-shape distribution of the intensities appears for the cross sections revealing the more dense jet regions in the core, while slight longitudinal asymmetries indicate an interaction between the jet plumes.
The growth of GeSn layers by molecular-beam epitaxy on Si (100) wafers coated with a germanium buffer layer is investigated. The properties of the fabricated structures are controlled by reflection high-energy electron diffraction, atomic-force microscopy, X-ray diffractometry, Rutherford backscattering, and Raman scattering. It is shown that GeSn layers with thicknesses up to 0.5 ?m and Sn molar fractions up to 0.073 manifest no sign of plastic relaxation upon epitaxy. The lattice constant of the GeSn layers within the growth plane is precisely the same as that of Ge. The effect of rapid thermal annealing on the conversion of metastable elastically strained GeSn layers into a plastically relaxed state is examined. Ge/GeSn quantum wells with Sn molar fraction up to 0.11 are obtained.
This article describes a genetic algorithm capable of fast search for optimum parameters of ion-optical systems with various types of reflective mirrors. Such an algorithm is an effective tool for solving optimization problems in ion and electron optics, where the use of analytical methods and direct programming becomes ineffective or impossible, and the stochastic search of variants consuming and costly. Genetic algorithm is an effective addition to standard developer tools and software environments such as SIMION-8-3D. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
We report geometry, energy, and some electronic properties of [n,4]- and [n,5]prismanes (polyprismanes): a special type of carbon nanotubes constructed from dehydrogenated cycloalkane C and Crings, respectively. Binding energies, interatomic bonds, and the energy gaps between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) have been calculated using density functional approach and nonorthogonal tight-binding model for the systems up to thirty layers. It is found that polyprismanes become more thermodynamically stable as their effective length increases. Moreover, they may possess semiconducting properties in the bulk limit. © 2015 Konstantin P. Katin et al.
The results of the experimental studies of CD4001BCN-NL CMOS chips on the impulse electric strength (IES) at two ambient temperatures (+25°C and +125°C) are given. The analysis of the obtained results showed that the ambient temperature effects on the impulse electric strength indices of the studied chip. The value and behavior of the IES can be described by the p-n-junction thermal damage model.
The results of the experimental studies of IC's electrical overstress (EOS) pulse hardness at two ambient temperatures (+25 degrees C and +125 degrees C) are given. The value and behavior of the EOS hardness can be described by the p-n junction thermal damage model
We propose a new semi-empirical method for estimation of Single Event Upset (SEU) cross-section for SRAM Dual Interlocked Cells (DICE) with known distance between neighboring sensitive volumes. The method is based on experimental analysis of SEU maps in sub-100 nm 6T SRAM along with layout considerations and SPICE simulations. It could help to significantly improve SEE robustness of modern CMOS VLSI by design. © 2015 IEEE.
At the present time, many publications on mixed matrix membranes (MMM) are concerned with the study of membranes containing nonspherical nanoparticles with high aspect ratios. Macroscopic characteristics of MMMs and their variations are known to be controlled by the parameters of a percolating cluster composed of incorporated particles in the host membrane. However, conditions providing the formation of percolating structures in films, the thickness of which is comparable to the dimensions of incorporated particles, can be appreciably different from the percolation scenario in isotropic infinite systems. In this work, the Monte Carlo method is used to define the conditions providing the formation of a percolating cluster composed of sticks at varying concentrations of sticks in finite membrane and at different ratios between membrane thickness and dimensions of sticks. In the above systems, percolation-induced changes show a threshold character and take place in a narrow concentration interval. Parameters of the as-formed MMMs are found to be unstable and sensitive to both film thickness and aspect ratio of sticks. (C) 2015 Elsevier B.V. All rights reserved
The first known numerical solution for the problem of transient processes in a resonant tunneling diode (RTD) in the presence of I-V curve hysteresis is found within a coherent model that incorporates a system of Schröbinger-Poisson equations with open boundary conditions. Transient currents are determined under various initial conditions and as functions of a wide range of parameters. The transition from the large-current state to the small-current one is analyzed in detail for the first time. This process assumes practical significance when RTDs are used as ultrafast switches. It is shown that the time of transition induced by a weak electric field may significantly exceed the expected -h/Γ, where Γ is the resonance level width. It is proven for the first time that the transition time may be reduced down to -h/Γ if a sufficiently strong field is applied. © 2015, Pleiades Publishing, Ltd.
X-ray analytical techniques are widely used in the world. By the way, due to the strong radiation-matter interaction, to design optical devices suitable for X-ray radiation remains still of wide interest. As a consequence of novel advanced material studies, in the last 30 years several typologies of X-ray lenses have been developed. In this work, a short review on the status of Polycapillary Optics (polyCO), from design and fabrication to various applications, has been presented making comparison of the results achieved by several groups through different X-ray optical elements. A focus is regarded for advanced X-ray imaging and spectroscopy tools based on combination of the modem polyCO hardware and the reconstruction software, available as homemade and commercially ones. Recent results (in three main fields, high resolution X-ray imaging, micro-XRF spectroscopy and micro-tomography) obtained at XLab Frascati have been discussed. (C) 2015 Elsevier B.V. All rights reserved.
We present measurements of electrons and positrons from the semileptonic decays of heavy-flavor hadrons at midrapidity (vertical bar gamma vertical bar 0.35) in Au + Au collisions at root(NN)-N-S
This paper gives a short review of the past and recent activities of the Atomic Collisions in Solids Lyon-group, in collaboration with other groups, in the field of high energy channelling. The ion-channelling programme was performed at GANIL-Caen and at GSI-Darmstadt. The electron-channelling programme started at ALS-Saclay for relativistic incident energies and was then extended to SPS-CERN for ultra-relativistic energies. The last part of this paper presents the electron-channelling experiments performed originally at ALS-Saclay, then at BTF-Frascati and more recently at LS-Saga, in order to observe the electron "internal clock" predicted in 1924 by L. de Broglie.
The hybrid scheme of the positron source for SPARC_LAB LNF facility (Frascati, Italy) is proposed. The comparison of the positron yield in a thin amorphous W converter of 0.1mm thickness produced by bremsstrahlung, by axial 〈100〉 and planar (110) channeling radiations in a W crystal is performed for the positron energy range of 1÷3MeV. It is shown that the radiation from 200MeV electrons (parameters of SPARC_LAB LNF Frascati) in a 10μm W crystal can produce positrons in the radiator of 0.1mm thickness with the rate of 10-102 s-1 at planar channeling, of 102-103 s-1 at bremsstrahlung and of 103-104 s-1 at axial channeling. © 2015 Elsevier B.V.
The article outlines a methodological approach, core specifics and capabilities of radiation identification of microelectronic devices at a specified exposure to ionizing radiation. © 2015 IEEE.
Radiation hardness of different samples of the same ICs can vary greatly from lot to lot, depending on the year or the country of production. However, it is assumed that radiation hardness of the samples from the same lot is the same too. The new chip uniformity test method based on ionization response comparison is offered.
In this article, we examine the possibility of applying the method of flicker noise spectroscopy to identification of anomalies in flux of cosmic rays (CR). Typically, such anomalies appears after intense solar outbursts, when the Sun emits into space giant blobs of plasma also called coronal mass ejection (CME). Identification of such anomalies in the CR flux allows us to detect CME, approaching to Earth. CMEs, powerful enough, can cause significant damage to electrical appliances. The present paper describes basic concepts of the flicker noise spectroscopy and principles of cosmic rays data processing algorithms. © 2015 The Authors.
The paper presents a physical model can qualitatively explain the observed experimental dependencies of reducing the pressure of the second and subsequent filling of partially filled porous medium. The model is based on an approach based on the fact that the pores in the porous medium is a chaotically arranged spherically shaped voids. If liquid is leaking out of such an environment is the formation of clusters associated with a liquid meniscus at the interface with air. Upon subsequent filling of the disappearance of the menisci is energetically favorable process that leads to a reduction in filling pressure. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The influence of construction of the buffer layer and misorientation of the substrate on the electrical properties of Insup0.70/supAlsup0.30/supAs/Insup0.76/supGasup0.24/supAs/Insup0.70/supAlsup0.30/supAs quantum wells on a GaAs substrate is studied. The temperature dependences (in the temperature range of 4.2 K < T < 300 K) and field dependences (in magnetic fields as high as 6 T) of the sample resistances are measured. Anisotropy of the resistances in different crystallographic directions is detected; this anisotropy depends on the substrate orientation and construction of the metamorphic buffer layer. In addition, the Hall effect and the Shubnikov–de Haas effect are studied. The Shubnikov–de Haas effect is used to determine the mobilities of electrons separately in several occupied dimensionally quantized subbands in different crystallographic directions. The calculated anisotropy of mobilities is in agreement with experimental data on the anisotropy of the resistances. © 2015, Pleiades Publishing, Ltd.
A uniform distribution of carbone nanotubes in a polymer matrix is required for the fabrication of composite materials. Since carbon nanotubes for introduction into polymers are preliminarily dissolved in water or organic solvents, it is necessary to create a uniform stable dispersion of carbon nanotubes in solvents. It is shown in this work that the concentration of nanotubes is a critical parameter determining the stability and composition of a solution. The kinetics of agglomeration of multiwalled carbon nanotubes dispersed in chloroform by sonication has been studied using optical spectroscopy and dynamic light scattering. It has been shown that such solutions can be stable for a long time at nanotube concentrations below 0.01 wt %. The intense agglomeration and sedimentation of nanotubes have been observed in a solution with a higher concentration. © Pleiades Publishing, Ltd., 2015.
The photophysical properties of colloid semiconductor quantum dots (QDs) and QD-containing composites attract increasing interest. The possibility of tuning of the luminescence wavelength by varying the QD size, their broad absorption spectrum and feasibility of obtaining QD-based thin layers and composites offer great prospects for application in photonics and optoelectronics. Some emerging trends in the development of QD-based light-emitting diodes and solar cells require embedding of QDs into a polymer matrix. Although there is evidence that the photophysical characteristics of QDs in such systems depend on the type of their surface ligands, yet, there are only few studies on this subject. Here, the luminescence characteristics CdSe/ZnS/Cds/ZnS QDs coated with aliphatic or aromatic ligands, embedded in a polymethylmethacrylate (PMMA) matrix, have been studied. The quantum yield (QY) of the QD/PMMA composites containing QDs with aliphatic ligands has been found to be three times higher compared to those containing QDs with aromatic ligands. We assume that this effect is due to hole capture on TP aromatic π-orbital. © 2015 The Authors.
An irreducible four-point vertex composed of the most-crossed diagrams involved in Bethe-Salpeter equation for an averaged two-photon propagator in a system of metal nanoparticles was calculated directly in coordinate representation without the traditional introduction of an EM-energy diffusion coefficient. These diagrams describe the interference of amplitudes corresponding to two possible ways for a photon to pass the closed loop on its trajectory. Localization is interpreted as a bound state generation of two virtual photons passing the loop clockwise and counterclockwise. This bound state is described by a pole of the irreducible vertex. The influence of this interference correction on light scattering and effective absorption by a random system of particles is investigated.
In the formalism of quantum operations, we investigate the effect of the amplitude and phase relaxation on the evolution of quantum states. A model of the polarizing qubit, whose noises depend on the spectral degree of freedom that manifests itself in the process of light propagation in the anisotropic medium with dispersion, is discussed. An approximate analytical model is proposed for evaluating the effect of the phase plate on the polarizing state, taking into account the dispersion of light. © Pleiades Publishing, Ltd., 2015.
The paper discusses nonuniform degradation effect for peripheral and central elements of CMOS-sensor light-sensitive surface under γ-irradiation. Spatial dependence of individual pixels' radiation hardness was investigated. The paper also assesses the possible causes of this phenomenon. © 2015 IEEE.
Transport of organic solvents (ethanol, propanol, ethylene glycol, glycerol and water) through the nanostructured glassy polymer poly[l-(trimethylsilyl)-l-propyne] (PTMSP) was investigated. Measurement of liquid flow through the membrane was carried out by novel dynamic pressure decay method (DPD) . This method let to measure permeability of this material in extremely wide ranges of temperature 30-90 °C and pressure 10-200 bar. Convection and diffusion transport of organic solvents was observed for the nanoscale pores. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
the article is devoted to the study of single event functional interrupts in microprocessors and microcontrollers. SEFI detection method is discussed. The influence of supply voltage, operating frequency and program code on SEFI cross section is examined. In addition the new simplified method of SEFI cross-section calculation based on critical memory space estimation is presented. © 2015 IEEE.
Nowadays surface assisted laser desorption/ionization is widely used in different analytical methods. Some of the most interest methods are based on laser irradiation of nanostructured surfaces, porous silicon (pSi) in particular. This method already proved itself in mass spectrometry due to the combination of high sensitivity and possibility of investigation of small molecules because of the absence of the influence of a substrate on the ion signal. In this work we present summarized results of our investigations dedicated to the use of the surface assisted laser desorption/ionization on pSi in ion mobility spectrometry (IMS), which is one of the most promising analytical methods in the area of fast detection of low concentrations of organic molecules. We use trinitrotoluene (TNT) as a substance to be investigated. Obtained results show that TNT ionization mechanism under laser irradiation is complicated and relates both to the electron emission process from the pSi surface and subsequent ion-molecular reactions in gas phase and to the surface proton transfer as well. © 2015 The Authors.
The possibility of earthquake prediction is one of the key open questions in modern geophysics. We propose an approach based on the analysis of common short-term candidate precursors (2 weeks to 3 months prior to strong earthquake) with the subsequent processing of brain activity signals generated in specific types of rats (kept in laboratory settings) who reportedly sense an impending earthquake a few days prior to the event. We illustrate the identification of short-term precursors using the groundwater sodium-ion concentration data in the time frame from 2010 to 2014 (a major earthquake occurred on 28 February 2013) recorded at two different sites in the southeastern part of the Kamchatka Peninsula, Russia. The candidate precursors are observed as synchronized peaks in the nonstationarity factors, introduced within the flicker-noise spectroscopy framework for signal processing, for the high-frequency component of both time series. These peaks correspond to the local reorganizations of the underlying geophysical system that are believed to precede strong earthquakes. The rodent brain activity signals are selected as potential “immediate” (up to 2 weeks) deterministic precursors because of the recent scientific reports confirming that rodents sense imminent earthquakes and the population-genetic model of Kirshvink (Soc Am 90, 312–323, 2000) showing how a reliable genetic seismic escape response system may have developed over the period of several hundred million years in certain animals. The use of brain activity signals, such as electroencephalograms, in contrast to conventional abnormal animal behavior observations, enables one to apply the standard “input-sensor-response” approach to determine what input signals trigger specific seismic escape brain activity responses. © 2014, Springer Basel.
A data-driven method was applied to Au+Au collisions at sNN=200GeV made with the STAR detector at RHIC to isolate pseudorapidity distance δη-dependent and δη-independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a δη-independent component of the correlation, which is dominated by anisotropic flow and flow fluctuations. It was also found to be independent of η within the measured range of pseudorapidity |η|<1. In 20-30% central Au+Au collisions, the relative flow fluctuation was found to be 34%±2%(stat.)±3%(sys.) for particles with transverse momentum pinfT/inf less than 2 GeV/c. The δη-dependent part, attributed to nonflow correlations, is found to be 5%±2%(sys.) relative to the flow of the measured second harmonic cumulant at |δη|>0.7. © 2015 The Authors.
The possibility to use the isotopically modified molybdenum as a constructive material for the fuel rods of light water and fast reactors is discussed. The calculations demonstrate that the isotopically modified molybdenum with an average neutron absorption cross-section comparable to that of zirconium can be obtained with the reasonable for practice cost by a cascade of gas centrifuges, specially designed for separation of non-uranium isotopes. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The system of automatic stabilization of the power factor for electric drive of gas centrifuges for uranium enrichment based on the principle of automatic search for the minimum of the total current in the electric capacitance as a function of compensating capacitor is considered. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Two-circuit system of automatic stabilization of the hydrodynamics of the cryogenic distillation column is considered. Control system eliminates flooding/depletion of column in long-term mode of operation when the accuracy of stabilization of the circulation flow is better than 1%. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Methods are proposed to estimate the relationship between probabilistic and order models for simulating functional failures of the large-scale integrated circuits (LSICs) based on Brauer’s fuzzy digital automaton and on a probabilistic automaton for reliability evaluation. In the first case, the behavior of the LSIC is determined by varying static and dynamic parameters; in the second case, by the statistical straggling of threshold failure levels. © 2015, Pleiades Publishing, Ltd.
Aspects of a new type of laser time-of-flight mass spectrometer are described in this letter. It is based on a wedge-shaped reflecting mirror and is used as an ion analyzer. The analyzer provides time focusing by both energy and divergence angle of ions. Time focusing of good quality is acquired in the energy range of +/-20% of the average ion energy, which is, at least, two times wider than the energy range of the known ion optical systems for similar applications. The mass resolution of the analyzer is -600, while overall dimensions are very small (10 x 10 x 5 cm).
We report electronic structure calculations in chemically functionalized linear cubane-based chains. The effects of covalent chemical attachments on chain transport properties are examined with nonorthogonal tight-binding model (NTBM) considering Landauer-Büttiker formalism. The covalent bonding of even a single-type functional group is shown to considerably alter the conductance of the chain. For similar radical doping density, electronic characteristics are found to range from insulator to narrow-gap semiconductor depending on the nature of the covalent bonding. Therefore it has become possible to tune electronic properties of the cubane-based one-dimensional oligomers by the functionalization for nanoelectronic applications. © 2015 Konstantin P. Katin and Mikhail M. Maslov.
The noise immunity of a 28-nm CMOS combinational logic (by the example of a two-phase inverter) to the effect of single nuclear particles is substantially higher if the constructive capacity between the outputs of a two-phase inverter is substantially lower than the threshold value. In this case, weakened noise enters the next two-phase element. It does not vary its logic state but transfers it into a locked state for the noise duration. The threshold value of capacity is larger for the CMOS two-phase inverters with symmetric switching characteristics upon switching both from 1 to 0 and from 0 to 1. The threshold critical characteristic makes it possible to compare the CMOS two-phase elements fulfilled according to different design rules and evaluate the gain of the two-phase logics under the effect of single particles on one of differential nodes. Critical charges of the two-phase elements substantially exceed (by a factor of at least 20 by the example of inverters) the critical charges of the CMOS traditional logic. © Pleiades Publishing, Ltd., 2015.
Total dose experimental results for different types of voltage regulators is presented and analyzed. The worst irradiation cases are revealed. © 2015 IEEE.
A method for calculating the external mass transfer in a contactor with a transverse confined flow of a viscous incompressible liquid (gas) past hollow fibers at low Reynolds numbers is proposed. The method is based on the concept of regular arrays of parallel fibers with a well-defined flowfield. As a simplest model system, a row of parallel fibers is considered, for which dependences of a drag force and an efficiency of a solute retention on the inter-fiber distance, membrane mass transfer coefficient, Peclet and Reynolds numbers are computed. The influence of the fluid inertia on the mass transport is studied. It is shown that a linear Stokes equations can be used for as higher Re numbers, as denser is the fiber array. In this case the flow field is independent on the Re number, and analytical solutions for the flowfield and fiber sorption efficiency (fiber Sherwood number) can be used. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Compton backscattering (CBS) of laser photons by relativistic electrons is widely used to design X-ray and gamma sources with a bandwidth better than 1% using a tight collimation. In order to obtain a reasonable intensity of the resulting beam one has to increase power of a laser pulse simultaneously with narrowing of the waist in the interaction point. It can lead to nonlinearity of CBS process which is affected on spectral characteristics of the collimated gamma beam (so-called "red-shift" of the spectral line, emission of "soft" photons with energy much less than the spectral line energy). In this paper we have analyzed such an influence using Monte-Carlo technique and have shown that even weak nonlinearity should be taken into account if the gamma beam is formed by a narrow aperture. © 2015.
A uniform distribution of carbone nanotubes in a polymer matrix is required for the fabrication of composite materials. Since carbon nanotubes for introduction into polymers are preliminarily dissolved in water or organic solvents, it is necessary to create uniform stable dispersion of carbon nanotubes in solvents. It has been shown in this work that the concentration of nanotubes is a critical parameter determining the stability and composition of a solution. The kinetics of agglomeration of multiwalled carbon nanotubes dispersed in chloroform by means of sonication has been studied by the methods of optical spectroscopy and dynamic light scattering. It has been shown that such solutions can be stable for a long time at concentrations of nanotubes below 0.01 wt %. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Hybrid membrane-sorption systems for producing oxygen-enriched air have been considered in terms of the general theory of multimodular separation systems with recirculation lines. The performance of the hybrid systems has been examined as a function of the product stream pressure. The hybrid and the membrane air separation systems have been compared. It has been shown that an optimal scheme is the membrane-sorption system in which a recycle is formed by returning the retentate stream from the membrane module to the feed stream using an ejector, with the feed gas mixture being sent to adsorbers from the ejector outlet. © 2015 Pleiades Publishing, Ltd.
Numerical study of single-hybrid membrane-sorption air separation system for enriching the air with oxygen were conducted. The effectiveness of such a system was analyzed, depending on selective sorbents and membranes under specified pressure ratio. A comparison of various modes membrane sorption system was done. The conclusion regarding the choice of the membrane and a sorbent for the system with a pressurized product stream was drawn. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The time-dependent photocurrent caused by the transient polarization of geminate pairs by an electric field after a short generation pulse is numerically simulated by the Monte Carlo method within Gaussian-disorder models. The photocurrent decreases almost steadily in the case of a rather wide spread of initial separations; however, due to the Coulomb interaction of "twins", the photoconductivity approaches its limiting value (free charge current) much faster than the full separation of pairs. However, the transient polarization of geminate pairs by an electric field contributes to the photoconductivity for a rather long time to affect experimental results, i.e., the photocurrent-decay law. Incorrect conclusions about the nature of recombination in a given material can be obtained, if the geminate-pair polarization current is neglected.
In this paper, change of gas permeability value, depending on orientation of polymer gas membrane, in a wide pressure range was investigated. Consistent patterns of asymmetric gas transfer through the PVTMS-membrane were established experimentally. Reverse asymmetric transport effect was observed, wherein the permeability from the direction of porous support prevails at the permeability from the direction of selective non-porous layer. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The asymmetry of the transport (permeation) of gases through track membranes with asymmetric pores has been experimentally investigated. Samples with different porosities and diameters of pores have been studied. The difference between the direct and reverse flows (asymmetry of transport) of helium, nitrogen, and carbon dioxide through membranes has been revealed. The flow from the narrow part of a pore (direct flow) is about 15% larger than the reverse flow. The interaction parameters characterizing the effect of the roughness of the inner surface of pores on the gas flow through a membrane have been determined. The surface flow effect has been demonstrated using the data obtained. Necessary conditions for the appearance of the asymmetric transport effect have been formulated. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Choice issue of membrane selectivity for helium extraction from natural gas was introduced. Two-stage membrane gas-separation circuit is used as gas-separation system, where recycle circuit is applied as the second stage. Selectivity choice recommendations are given from the energy-saving standpoint, considering to different degrees of helium extraction. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
In this work comparison of the desorption effectiveness of picosecond and nanosecond laser sources ( = 266, 532 nm) were carried out to investigate the possibility of creating a non-contact sampling device for detectors of explosives on the principles of ion mobility spectrometry (IMS) and field asymmetric ion mobility spectrometry (FAIMS). The results of mass spectrometric studies of TNT (2,4,6-Trinitrotoluene), HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), RDX (1,3,5-Trinitro-1,3,5-triazacyclohexane) laser desorption from a quartz substrate are presented. It is shown that the most effective laser source is a Nd:YAG3+ laser ( = 266 nm; E = 1 mJ; = 5-10 ns; q = 108 W/cm2). The typical desorbed mass is 2 ng for RDX, 4-6 ng for TNT and 0.02 ng HMX per single laser pulse. The results obtained make it possible to create a non-contact portable laser sampling device operating in frequency mode with high efficiency. © 2015 The Authors.
Coagulating systems are characterized by the fact that aggregates of masses g and l react irreversibly to form a larger aggregate of mass . The reaction rates for this process are assumed to depend only on the particle masses. This model is described by the corresponding kinetic equations. If the are assumed to grow fast enough, it happens that, at some finite time tinfc/inf, a fraction of the mass goes into a cluster of infinite size. Near and at the gel time, the mass spectrum cinfg/inf(t) can be described in scaling terms, that is, there exists a divergent typical mass in terms of which the spectrum can be expressed, as well as two exponents describing the g-dependence of the mass spectrum. These exponents have been extensively studied, both numerically and in terms of the case in which , which is exactly solvable. So far, the exact model strongly suggested the validity of certain general expressions for these exponents in terms of the homogeneity degree of the . These, however, were not confirmed numerically. In the following, we study the exact model in the case in which the initial conditions display an algebraic tail, and show that, in this case, the scaling exponents can be calculated analytically and do not conform to the expressions initially suggested. © 2015 IOP Publishing Ltd.
Negatively charged ions from the alpha particle tracks are detected by the discharge wire counter opened to the air. Ion clusters are transferred from the particle tracks to the detector volume by an air flux. It allows a remote detection of very low concentrations of alpha particles. In contrast to the existing long-range alpha particle detection technique this method employs a detector working in a counting mode using a gas discharge method with an open-air proportional counter that provides sharp selectivity and accuracy of measurements. The device allows to detect alpha contamination over large surface areas, including places hard to reach, using different nozzles such as the tube nozzle or disc nozzle. The basic parameters of the device are: detection distance - 0.5m; time of detection - 10s; the sensitivity per unit area - 0.05Bq/cmsup2/sup. Also the auto-calibration technique and results are presented. That allows using the device under different ambient conditions by making an automatic recalibration. © 2015 Elsevier Ltd.
Dihadron angular correlations in d + Au collisions at √sNN = 200 GeV are reported as a function of the measured zero-degree calorimeter neutral energy and the forward charged hadron multiplicity in the Au-beam direction. A finite correlated yield is observed at large relative pseudorapidity (δη) on the near side (i.e. relative azimuth δϕ~0). This correlated yield as a function of δη appears to scale with the dominant, primarily jet-related, away-side (δϕ~π) yield. The Fourier coefficients of the δϕ correlation, Vinfn/inf=〈cos n δ ϕ〉, have a strong δη dependence. In addition, it is found that Vinf1/inf is approximately inversely proportional to the mid-rapidity event multiplicity, while Vinf2/inf is independent of it with similar magnitude in the forward (d-going) and backward (Au-going) directions. © 2015 The Authors.
This paper presents the study of transient radiation effects in SOI CMOS RF IC's and discrete MOS transistors. Experiments show that the sensitivity of SOI RF IC's (gain blocks, mixers, VCO etc.) to transient irradiations (dose rate) is mainly determined by the transient response of RF characteristics i.e. output power, output frequency, power / conversion gain, rather than supply transient photocurrent. SOI VCO demonstrates a minimal threshold dose rate (upset-free level) below than 109 rad(Si)/s, limited by the output frequency variations of ±20% and recovery time up to 100 μs with a maximum dose rate of 5×1012 rad(Si)/s. It is also shown that the long-Term transient recovery of the RF characteristics and super-linear dependence of the supply photocurrent vs dose rate are the dominating transient radiation effects in SOI CMOS RF IC's. © 2015 IEEE.
The article describes an original technique for TID testing of complex VLSI circuits (microprocessors) based on combined use of parametric and functional control. The resulting dependences obtained in radiation experiment are qualitatively confirmed by circuit simulation. © 2015 IEEE.
Polyphenylquinolines (PPQs), which are compound donor–acceptor complexes, are studied by luminescence-kinetic spectroscopy. It is shown that, as the π system becomes stronger on passing from (O, C) to (O, IC) and (PhA, C), an increase in the lifetime T of the excited state is first observed, and for the strongest charge-transfer complex PPQ (PhA, IC), whose luminescence kinetics is described by two exponentials, the lifetime decreases to a value equal to T of PPQ (O, C). This indicates that this complex has two emitting centers localized in the arylene moiety and in the phenylquinoline ring and thereby confirms a previously made conclusion that compound donor–acceptor complexes are formed in polyphenylquinolines with a branched π system of compound D–A complexes. © 2015, Pleiades Publishing, Ltd.
Excitation energies of singlet and triplet ππ∗ and nπ∗ transitions are calculated for chalcone and its aminoderivatives using quantum chemical approach. Solvent impact on the molecular geometry and excited state energies is investigated. Both universal (dipole-dipole) and specific (H-bond formation with C=O group) interactions are taken into account. Dipole-dipole interactions are shown to stabilize the excited Sππ∗ state in the systems studied in the same way as for others heteroaromatic luminophores. Specific interactions in protic solvents cause in addition significant geometry deformation to the non-planar structure of the chromophore. Large intramolecular spin-orbit coupling between the lowest singlet and triplet excited states in the latter case is revealed. It proves that intersystem crossing between these states should be the main channel of fluorescent quenching of 4-(N,N′-dimethylamino)-chalcone in protic solvents. © 2015 Elsevier B.V. All rights reserved.
An initially empty (no edges) graph of order M evolves by randomly adding one edge at a time. This edge connects either two linked components and forms a new component of larger order (coalescence of graphs) or increases (by one) the number of edges in a given linked component (cycling). Assuming that the vertices of the graph have a finite valence (the number of edges connected with a given vertex is limited) the kinetic equation for the distribution of linked components of the graph over their orders and valences is formulated and solved by applying the generating function method. The evolution process is shown to reveal a phase transition: the emergence of a giant linked component whose order is comparable to the total order of the graph. The kinetics of growth of this component is studied for arbitrary initial conditions. Found are the time dependences of the average order and the valence of the giant component. The distribution over orders and valences of the linked components of the graph is derived for an initially empty graph comprising M bare polyvalent vertices.
The time evolution of a random graph with varying number of edges and vertices is considered. The edges and vertices are assumed to be added at random by one at a time with different rates. A fresh edge connects either two linked components and forms a new component of larger order g (coalescence of graphs) or increases (by one) the number of edges in a given linked component (cycling). Assuming the vertices to have a finite valence (the number of edges connected with a given vertex is limited) the kinetic equation for the distribution of linked components of the graph over their orders and valences is formulated and solved exactly by applying the generating function method for the case of coalescence of trees. The evolution process is shown to reveal a phase transition: the emergence of a giant linked component whose order is comparable to the total order of the graph. The time dependencies of the moments of the distribution of linked components over their orders and valences are found explicitly for the pregelation period and the critical behavior of the spectrum is analyzed. It is found that the linked components are. distributed over g with the algebraic prefactor g(-5/2). The coalescence process is shown to terminate by the formation of the steady-state. spectrum with the same algebraic prefactor.
The atmospheric aerosol is among the most significant environmental and climate formation factors. Therefore, studies of the physicochemical properties of aerosols and the dynamics of aerosol formation are of paramount importance for forecasting climatic changes on the Earth. The spread of aerosols from the source of pollution dramatically affects human health. A special role is played by secondary nanoaerosols, which easily penetrate the human body. In this brief overview, we present updated information on the physical chemistry of atmospheric nanoaerosols. Special attention is focused on recent advances in the theories of aerosol particle formation, charging, and growth. © 2015, Pleiades Publishing, Ltd.
Liquid metal embrittlement (LME) manifests itself as a sudden destruction of a metal sample if it is covered by a thin liquid film of eutectic mixture of specially selected metals. The proposed theoretical model of this phenomenon is based on an assumption related to the possibility of electromagnetic field localization in folds of interface between the phases or components of eutectic mixture filling cracks in solid metal surface (the typical example is In-Ga eutectic on Al-surface). Based on simultaneous presence of three different components in each space point of eutectic mixture (homogeneous In+Ga melt, solid In, and solid Ga), the system of interface folds could be simulated by the Brouwer surface - well known in topology. This surface separates three different components presented at each of its point. Such fractal surfaces posses by a finite volume. The volume occupied by the surface is defined as a difference between the eutectic mixture volume and the sum of volumes of its components. We investigate localization of external electromagnetic radiation in this system of folds. Due to very large magnitude of effective dielectric permeability of the considered system, at relative small volume change and fractal dimension of interface close to the value 3, the wave length of incident radiation inside the system is considerably decreased and multiscale folds are filled with localized photons. A probability of this process and the life time of the localized photons are calculated. The localized photons play crucial role in destruction of primary cracks in the metal surface. They are capable "to switch of" the Coulomb attraction of charge fluctuations on opposite "banks" of the crack filled with the eutectic. As a result, the crack could break down.
It is shown that, under conditions of light localization in a system of scatterers, effective photon-photon interaction appears. This interaction is related to neither nonlinearity of medium nor nonlocal interaction of polarization-entangled photon pairs. It is related to the complex topology of photon trajectories. Taking into account this interaction, the scattering cross section of photon pairs is calculated. It is shown that this cross section contains only an extra degree of the small Rayleigh factor in comparison with the classic Rayleigh cross section. The proposed approach could potentially open a gate for controlling light by alternative light fluxes, eliminating the need for slow optoelectronic converters.
Measurements of bottomonium production in heavy-ion and p + p collisions at the Relativistic Heavy Ion Collider (RHIC) are presented. The inclusive yield of the three states, (1S + 2S + 3S), was measured in the PHENIX experiment via electron-positron decay pairs at midrapidity for Au + Au and p + p collisions at root sNN = 200 GeV. The (1S + 2S + 3S) - e(+)e(-) differential cross section at midrapidity was found to be B(ee)d sigma/dy = 108 +/- 38 (stat) +/- 15 (syst) +/- 11 (luminosity) pb in p + p collisions. The nuclear modification factor in the 30% most central Au + Au collisions indicates a suppression of the total. state yield relative to the extrapolation from p + p collision data. The suppression is consistent with measurements made by STAR at RHIC and at higher energies by the CMS experiment at the Large Hadron Collider.
One of the primary goals of nuclear physics is to understand the force between nucleons, which is a necessary step for understanding the structure of nuclei and how nuclei interact with each other. Rutherford discovered the atomic nucleus in 1911, and the large body of knowledge about the nuclear force that has since been acquired was derived from studies made on nucleons or nuclei. Although antinuclei up to antihelium-4 have been discovered and their masses measured, little is known directly about the nuclear force between antinucleons. Here, we study antiproton pair correlations among data collected by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC), where gold ions are collided with a centre-of-mass energy of 200 gigaelectronvolts per nucleon pair. Antiprotons are abundantly produced in such collisions, thus making it feasible to study details of the antiproton-antiproton interaction. By applying a technique similar to Hanbury Brown and Twiss intensity interferometry, we show that the force between two antiprotons is attractive. In addition, we report two key parameters that characterize the corresponding strong interaction: the scattering length and the effective range of the interaction. Our measured parameters are consistent within errors with the corresponding values for proton-proton interactions. Our results provide direct information on the interaction between two antiprotons, one of the simplest systems of antinucleons, and so are fundamental to understanding the structure of more-complex antinuclei and their properties. © 2015 Macmillan Publishers Limited. All rights reserved.
We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central d + Au and minimum bias p + p collisions at root s(NN) = 200 GeV. The charged hadron is measured at midrapidity vertical bar eta vertical bar 0.35, and the energy is measured at large rapidity (-3.7 eta -3.1, Au-going direction). An enhanced near-side angular correlation across vertical bar Delta eta vertical bar 2.75 is observed in d + Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength v(2) for inclusive charged hadrons at midrapidity up to p(T) = 4.5 GeV/c. We also present the measurement of v(2) for identified pi(+/-) and (anti)protons in central d + Au collisions, and observe a mass-ordering pattern similar to that seen in heavy-ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from p + Pb at root s(NN) = 5.02 TeV. The magnitude of the mass ordering in d + Au is found to be smaller than that in p + Pb collisions, which may indicate smaller radial flow in lower energy d + Au collisions.
We report on measurements of dielectron (e(+) e(-)) production in Au + Au collisions at a center-of-mass energy of 200 GeV per nucleon-nucleon pair using the STAR detector at BNL Relativistic Heavy Ion Collider. Systematic measurements of the dielectron yield as a function of transverse momentum (p(T)) and collision centrality show an enhancement compared to a cocktail simulation of hadronic sources in the low invariant-mass region (M-ee 1 GeV / c(2)). This enhancement cannot be reproduced by the rho-meson vacuum spectral function. In minimum-bias collisions, in the invariant-mass range of 0.30-0.76 GeV / c(2), integrated over the full pT acceptance, the enhancement factor is 1.76 +/- 0.06 (stat.) +/- 0.26 (sys.) +/- 0.29 (cocktail). The enhancement factor exhibits weak centrality and pT dependence in STAR's accessible kinematic regions, while the excess yield in this invariant-mass region as a function of the number of participating nucleons follows a power-law shape with a power of 1.44 +/- 0.10. Models that assume an in-medium broadening of the rho-meson spectral function consistently describe the observed excess in these measurements. Additionally, we report on measurements of omega-and phi-meson production through their e+ e(-) decay channel. These measurements show good agreement with Tsallis blast-wave model predictions, as well as, in the case of the phi meson, results through its K+ K- decay channel. In the intermediate invariant-mass region (1.1 Mee 3 GeV / c(2)), we investigate the spectral shapes from different collision centralities. Physics implications for possible in-medium modification of charmed hadron production and other physics sources are discussed.
We present the first measurement of elliptic (v2) and triangular (v3) flow in high-multiplicity He3+Au collisions at sNN=200GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in He3+Au and in p+p collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the He3+Au system. The collective behavior is quantified in terms of elliptic v2 and triangular v3 anisotropy coefficients measured with respect to their corresponding event planes. The v2 values are comparable to those previously measured in d+Au collisions at the same nucleon-nucleon center-of-mass energy. Comparisons with various theoretical predictions are made, including to models where the hot spots created by the impact of the three He3 nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. The agreement of these models with data may indicate the formation of low-viscosity quark-gluon plasma even in these small collision systems. © 2015 American Physical Society.
The mechanisms of the ejection of aluminum and copper microparticles from the free surfaces of these metals have been studied under conditions of the escape of a moderate-intensity shock wave from a sample. The free surfaces of samples contained 0.7–0.9 mm deep artificial wells and protrusions simulating (on a greater scale of 10: 1) the natural surface roughness retained upon mechanical processing. The pressure in a shock-wave pulse at the base of a protrusion was controlled within P = 5–20 GPa (i.e., below the melting region), and the variable duration of pressure pulses was 0.02, 0.2, and 1 μs. Analysis of the free surfaces of postloaded samples showed that, for certain loading and roughness parameters, the ejection of metal from vertices of protruding ridges or pyramids (as a result of the longitudinal fracture) was about ten times greater than the amount of metal ejected in the form of cumulative jets from wells. The amount of ejected metal and the size distribution of metal microparticles were quantitatively characterized using “soft collecting targets” and by measuring mass losses of samples upon fracture. © 2015, Pleiades Publishing, Inc.
In this work the analysis of possible approaches to SEU-hardness testing for SRAM with error correction were conducted. Efficiency of the aproach proposed by Aeroflex was evaluated, and the results of experimental investigation for 16 Mbit SRAM under heavy ion and focused laser irradaition were provided. © 2015 IEEE.
A simple semi-analytical solution is proposed for the verification of numerical codes for modeling of unsteady gas flows in strong centrifugal fields. The gas flow is driven by a source/sink of energy and by an external force (deceleration/acceleration of the gas rotation) acting on the gas at a given frequency. In the semi-analytical solution, the rotor is infinite, while the given forces vary harmonically with a given wave-length along the axial coordinate. As a result, the unsteady flow problem is reduced to a system of ordinary differential equations, which can be quickly solved to any prescribed accuracy. A similar unsteady problem is solved numerically with the rotor length equal to the wavelength of the external force along the axis of rotation. The periodicity of the solution is prescribed at the end faces of the rotor. As an example, the semi-analytical solution is compared with the numerical ones obtained with different boundary conditions and mesh resolution in radial direction. The comparison confirms that the problem formulations are equivalent in both cases. The semi-analytical solution allows us to determine optimal mesh resolution and accuracy of the calculations. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
A rigorous way is described to increase the resolution of laser time-of-flight (TOF) mass spectrometers with an axially symmetric electrostatic analyzer by more than one order of magnitude. The inventive method consists in the introduction of a reflector into the ion optics of the mass spectrometer, which generates a second-order temporal aberration with an opposite polarity with respect to the aberration occurring in the free plasma drift space because of the compensation of time aberrations by energy of the second order, optimization of the ion-optical scheme of a laser time-of-flight mass spectrometer, and taking into account the partial compensation of the third-order aberrations, the resolution of the mass spectrometer is increased to (1-2) x 10(4). Theoretical calculations justifying the proposed method are presented.
In this article we present the results of micro-Raman studies of graphene grown on copper foil surface by atmospheric pressure CVD using decane as precursor, nitrogen as carrier gas with zero flow of hydrogen. Analysis of Raman spectroscopy data showed that film contains spots with single layer thick graphene. We observed significant blue shift of 2D and G bands positions for mono-atomically thick graphene on copper foil. Following literature we relate this shift to the strain induced by the presence of copper substrate. Moreover, we observed changes in the defectiveness of graphene layers after the transfer, which was related to the appearance of chemically-induced defects and defects induced by changes in the mechanical strain. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The phenomenon of transition to a metastable state of the liquid dispersed in confinement was investigated in this work. Two hydrophobic porous media with similar characteristics has been used. This porous media had identical material (Si02), surface modification and comparable pore size distribution function, but different pores geometry: quasi-cylindrical (SBA) and quasi-spherical (KB). The characteristics of porous media and results of investigation the non-wetting liquid dispersion in porous media phenomenon at temperatures system from 293 to 343 K and filling the pores of porous media from 10 to 100 percents was presented. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The results of the Monte-Carlo numerical simulations of the particle diffusion in the hybrid membranes which consists of anisotropic matrix (polymer) with embedded tubular particles (nanotubes) is presented. The dependence of diffusion coefficient for the random walk of spherical particles from the characteristics of heterogeneous material is calculated. It is shown that the diffusion coefficient of the particles in the membrane varies nonlinearly with increasing of the concentration of embedded particles. A significant change of the diffusion time occurs when a particle's concentration is close to the percolation threshold. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
We found that the energy deposition fluctuations in the sensitive volumes may cause multiplicity scatters in the multiple cell upsets (MCU) in the nanoscale (with feature sizes less than 100 nm) memories. Microdosimetric model of the MCU cross-section dependence on LET is proposed. It was shown that ideally a staircase-shaped cross-section vs LET curve spreads due to energy-loss straggling into a quasi-linear dependence with a slope depending on the memory cell area, the cell critical energy and the efficiency of charge collection. © 2015 IEEE.
New experimental results using both ion and laser facilities are presented to analyse four multiple cell upset (MCU) mechanisms in SRAMs. Equations describing basic MCU mechanisms were provided. © 2015 IEEE.
There is a growing need for the development of atomic and nuclear frequency standards because of the important contribution of methods for precision time and frequency measurements to the development of fundamental science, technology and the economy. It is also conditioned by their potential use in optical clocks and quantum logic applications. It is especially important to develop a universal method that could allow one to use ions of most elements effectively (including ones that are not easily evaporated) proposed for the above-mentioned applications. A linear quadrupole ion trap for the optical spectroscopy of electron and nuclear transitions has been developed and evaluated experimentally. An ion source construction is based on an ultra-high vacuum evaporator in which a metal sample is subjected to an electron beam of energy up to 1 keV, resulting in the appearance of gaseous atoms and ions of various charge state. The linear ion trap consists of five successive quadrupole sections including an entrance quadrupole section, quadrupole mass filter, quadrupole ion guide, ion-trap section and exit quadrupole section. The same radiofrequency but a different direct current voltage feeds the quadrupole sections. The instrument allows the mass- and energy-selected trapping of ions from ion beams of various intensities and their localization in the area of laser irradiation. The preliminary results presented show that the proposed instrument and methods allow one to produce effectively up to triply charged thorium ions as well as to trap ions for future spectroscopic study. The instrument is proposed for future use in optical clocks and quantum logic application development. © IM Publications LLP 2015. All rights reserved.
Pulsed laser sources are widely used for high dose rate effects modeling in modern ICs. In this research, a significant effect of optical beam polarization orientation on ionization response of ICs with design rules of less than the laser wavelength was demonstrated. This approach suggests taking into account the influence of a laser parameters on IC's dose rate response.
The generation of neutrons in a coaxial vacuum diode with laser-plasma source of deuteron on anode and outer hollow cylindrical cathode is investigated. The experiments were carried out at accelerating voltages in the diode gap of UinfA/inf ≤ 280 kV for two configurations of the electrode system: the cathode made from magnetic NdFeB compound material, providing suppression of electrons stray currents in the accelerating gap, and an aluminum A1 cathode. For the magnetic field inductance on the axis of the NdFeB cathode about B 0.4 on the D(d, n)3He reaction the maximum neutron output in the total solid angle Q = 5×107 neutrons per pulse was received. The absence of magnetic insulation reduced the accelerating voltage on the diode gap and the neutrons output. © 2015 The Authors.
t. © 2015 The Authors.
An analytic model for calculating the current–voltage characteristic of disordered organic layers with unipolar conduction is developed for conditions when the injected carrier density is sufficiently high to consider deep state population and the current is space-charge-limited. The mobility is calculated based on the transport level concept. The proposed model, being physically clear, well describes the experimental current–voltage characteristics of polymers in a wide temperature range (except for extreme case of high voltages, where the transport level concept should be modified). Thus, this model simplifies calculation and improves the reliability of the theoretical modeling of carrier transport in organic light-emitting diodes. © 2015, Pleiades Publishing, Ltd. t. © 2015 The Authors.
An analytic description of electric field and temperature dependences of mobility is developed on the base of extended transport level concept in the framework of Gaussian disorder model, providing low concentration of charge carriers. Field-dependent percolation factor was used in an equation for transport level. Results are in good agreement with well-known Monte Carlo simulations at weak and moderate electric field strength (up to 106 V/cm at typical parameters), providing that energetically upward jumps still dominate conductivity. It is enough for most applications in organic electronics. Concentration dependence of a transport level is discussed. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
An analytic model of mobility dependence on charge-carrier concentration based on percolation theory was modified by the use of the transport level concept, including field dependence of transport level. This model was applied to calculations of I-V characteristics of a single organic layer under space-charge limited regime. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Experimental setup based on visible and NIR spectral range microscope with laser port and picosecond laser is developed for silicon integrated circuit (IC) failure analysis. The possibility of visualizing the topology of the submicron technology silicon structures from the back side of the crystal through the substrate is shown. Main features of new setup are demonstrated by some results of backside focused pulsed laser beam initiated latchup effect study. The possibility of the localization of the latchup sensitive areas under focused laser irradiation is shown. NIR light emission accompanying the latchup effect is observed and analyzed. The practical aspects of NIR microscopy for failure analysis under backside laser irradiation are discussed. © 2015 The Authors.
Lasers can be used in combination with ions for SEE testing. The most practical technique of such tests is based on the comparison between the SEE cross-section vs. ion LET and the SEE cross-section vs. laser pulse energy. However there can be a significant error in the latter curve since the effective laser energy is not the same over different locations on the chip due to the IC's metallization nonuniformity. This nonuniformity can be taken into account through the optical beam induced current (OBIC) examination which is considered in this article. © 2015 IEEE.
The 32-channels ASIC with a unique dynamic range from 1 to 40000 mips, signal to noise ratio not less than 2.5 at a shaper peaking time of 2 mu s and a low power consumption of 1.5 mW/channel has been designed. The transfer function of the charge sensitive amplifier (CSA), having two subranges of various gains, allowed to reach high dynamic range of the readout electronics. The subranges are automatically switched. Two ASICs were installed on a ladder construction which also contains an ADC, a microprocessor and a power supply. The ASIC and the ladder were created for the minicalorimeter of the NUCLEON experiment. The goal of the NUCLEON satellite mission is to measure the elemental (Z from 1 to 30) energy spectra of high-energy (10(11)-10(15) eV) cosmic rays. The ladder has been tested at the SPS. The ladder can also be used for other future HEP and space cosmic ray experiments.
Numerical modelling and optimization of the gas flow and isotope separation in the Iguasu gas centrifuge (GC) for uranium enrichment have been performed for different lengths of the rotor. The calculations show that the specific separative power of the GC reduces with the length of the rotor. We show that the reduction of the specific separative power is connected with the growth of the pressure in the optimal regime and corresponding growth of temperature to prevent the working gas sublimation. The specific separative power remains constant with the growth of the rotor length provided that the temperature of the rotor is taken to be constant. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
THz radiation source from electrons moving inside a corrugated channel in dielectric media is considered. Spectral angular distribution of radiation is shown to depend strongly on target and bunch parameters. Numerical optimization of THz source is performed for the parameters of LUCX facility in KEK, Japan. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The results of Monte-Carlo simulations of the percolation clusters of carbon nanotubes in the two-dimensional finite thickness membranes are presented. Simulations are performed by the Hoshen-Kopelman and modified Newman-Ziff algorithms. The dependence of the particles critical concentration (percolation thresholds) on the membrane aspect ratio are calculated. The critical concentration decreases with increase of the membrane aspect ratio. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
We present measurements of pi(-) and pi(+) elliptic flow, v(2), at midrapidity in Au + Au collisions at root s(NN) = 200, 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV, as a function of event-by-event charge asymmetry, A(ch), based on data from the STAR experiment at RHIC. We find that pi(-) (pi(+)) elliptic flow linearly increases (decreases) with charge asymmetry for most centrality bins at root s(NN) = 27 GeV and higher. At root s(NN) = 200 GeV, the slope of the difference of v(2) between pi(-) and pi(+) as a function of A(ch) exhibits a centrality dependence, which is qualitatively similar to calculations that incorporate a chiral magnetic wave effect. Similar centrality dependence is also observed at lower energies.
Deflection of 400 GeV/. c protons by a short bent silicon crystal was studied at the CERN SPS. It was shown that the dechanneling probability increases while the dechanneling length decreases with an increase of incident angles of particles relative to the crystal planes. The observation of the dechanneling length reduction provides evidence of the particle population increase at the top levels of transverse energies in the potential well of the planar channels. © 2015 The Authors.
In ideal two-stage collimation systems, the secondary collimator-absorber should have its length sufficient to exclude practically the exit of halo particles with large impact parameters. In the UA9 experiments on the crystal assisted collimation of the SPS beam a 60 cm long tungsten bar is used as a secondary collimator-absorber which is insufficient for the full absorption of the halo protons. Multi-turn simulation studies of the collimation allowed to select the position for the beam loss monitor downstream the collimation area where the contribution of particles deflected by the crystal in channeling regime but emerging from the secondary collimator-absorber is considerably reduced. This allowed observation of a strong leakage reduction of halo protons from the SPS beam collimation area, thereby approaching the case with an ideal absorber. © 2015 The Authors.
We report the observation of transverse polarization-dependent azimuthal correlations in charged pion pair production with the STAR experiment in p(up arrow) + p collisions at RHIC. These correlations directly probe quark transversity distributions. We measure signals in excess of 5 standard deviations at high transverse momenta, at high pseudorapidities eta 0.5, and for pair masses around the mass of the rho meson. This is the first direct transversity measurement in p + p collisions.
Viscoelastic properties of the molecular liquid consisting of 4,4′-N,N′-dicarbazolylbiphenyl (CBP) molecules near the glass transition temperature are investigated by molecular dynamics simulations. The relaxation dynamics is analyzed by considering each molecule as a point-like oriented particle. The dependence of the calculated properties on the coarse-grain parameter used in the calculation of orientation correlation is analyzed. The divergence of α-relaxation times is described by the Vogel-Fulcher-Tammann law and the mode coupling theory. The basic concepts of the glass transition theory are applied to a real amorphous organic semiconductor. © 2015 Published by Elsevier B.V.
The electronic coupling matrix element responsible for positive charge carrier (hole) transport has been calculated for a variety of 4,4′-bis(9-carbazolyl)-biphenyl dimers corresponding to a disordered solid matrix. A procedure applying the computational scheme to a real system (organic molecules with a large molecular mass) is proposed. The consistency of the results with the existing model concept of hopping conductivity in organic semiconductors is discussed. © 2015 Pleiades Publishing, Ltd.
Many key features of the protein adsorption on the silica surfaces still remain unraveled. One of the open questions is the interaction of nonpolar side chains with siloxane cavities. Here, we use nonequilibrium molecular dynamics simulations for the detailed investigation of the binding of several hydrophobic and amphiphilic protein side chains with silica surface. These interactions were found to be a possible driving force for protein adsorption. The free energy gain was larger for the disordered surface of amorphous silica gel as compared to α-quartz, but the impact depended on the type of amino acid. The dependence was analyzed from the structural point of view. For every amino acid an enthalpy-entropy compensation behavior was observed. These results confirm a hypothesis of an essential role of hydrophobic interactions in protein unfolding and irreversible adsorption on the silica surface. © 2015 American Chemical Society.
Possible breaking of CP-invariance of the strong interactions is one of the actual problems in quantum chromodynamics. The preliminary estimations of correlators within the framework of the chiral magnetic effect are presented for different beam types and collision energies. These correlators characterized the asymmetry of the emission of charged particles with respect to the reaction plane in non-central nucleus-nucleus collisions are calculated for two various nuclear densities, namely, for approach of hard sphere and for two-component Fermi model. © 2015 The Authors.
A novel study on a different use of polycapillary optics is presented. The scope of this study is to achieve an efficient radiation collimation due to handled beam profiling that avoids the typical one based on total external reflection into the capillary channel. For this purpose a vibration is applied to a monocapillary in order to emulate a "virtual roughness" on the channel internal wall surface. The transmission properties of such a system for different vibrational states are discussed. © 2015.
Dynamics of the buckled Stone-Wales defect in graphene is studied by means of computer simulation. Thermally activated switching between two degenerate sine-wave-like configurations of the defect is traced in real time. Transition trajectory is found to be rather complex and pass through a multitude of near-planar, wave-like, and irregular configurations. Surprisingly, the switching time fluctuates strongly and can be up to an order of magnitude longer or shorter than the value given by the Arrhenius formula. This is due to a peculiar shape of the potential relief in the neighborhood of sine-wave-like configurations and, as a result, the occurrence of two radically different characteristic times. © 2015 Elsevier B.V. All rights reserved.
The interaction of Stone-Wales defects in graphene has been investigated by computer modeling. It has been shown that the defects can both repel and attract each other (depending on their mutual orientation and distance between them). The determining role in the attraction mechanism is apparently played by strong anisotropic deformation of graphene by defects. The constructive interference of wavy distortions of the monolayer structure formed by defects leads to large transverse atomic displacements, which can be one of the causes of the experimentally observed "crumpled" graphene texture.
A 2.2-ppm/°C voltage reference is proposed for use as an analog to digital conversion reference in readout application-specific integrated circuits. The proposed circuit uses resistors available for the standard CMOS process with opposite sign temperature coefficients. That enables a superposition of two bandgap schemes, one with downward concave and the other upward concave voltage temperature dependence. Using two similar schemes for the task allows topology matching of single circuit elements. The providen schematic is verified by simulation of the reference in 0.35 μm technology. The simulated reference provides a voltage of about 1.2 mV with the variation of ∼300 μV in the temperature range -20 to 85°C. The operating temperature range is the reduced industrial grade, with a supply voltage of 3.3V, and an average consumption current of 6:4μA in the operating temperature range © 2014 University of West Bohemia.
A preamplifier for comparators of precision low-power consumption analog-digital converters is presented. In order to lower the average consumption current of amplifier cascades, the capacitors, which fulfill the function of current sources during charging at the comparison stage, are used in them as the dynamic load. A correction circuit of the zero bias error for amplifiers of this type is developed. Modeling of the device using CMOS elements with a design rule of 0.35 μm from library XA035 of factory XFAB showed that the average current consumption at an operating frequency of 1 MHz is about 7 μA.
The article considers general principles for the development of competency building approach in vocational education. The authors state the importance of competency building approach in engineering education at the present stage of market relations proceeding from the position of American sociologist and economist Schumpeter, according to whom innovations in mass commodity production involve constant updating of models and the range of products. From this position, it follows that dynamic innovation in production is only possible with two factors, operating simultaneously: intertwining of science and production and involvement of experts, able to carry out the transfer of scientific production into consumable products. This type of production requires analytical engineers with both formal (mathematical) and analytical (dialectical) thinking, who are able to bring together the accurate manufacturing technology and heuristics. The authors call this new type of engineers "engineer-innovators". Sociologists agree that the high-quality training of engineers-innovators should be carried out on the basis of competency building approach, but have not been able yet to create the functional structure of the competency-based training for engineers-innovators. The results of the expert survey enabled the authors to perform a statistical factor analysis and build the optimal structure (content) of competency-based training for engineers-innovators in institutions of higher education and courses of advanced studies. Structural indicators identified by the authors through factor analysis can be used when creating textbooks for competency-based training at the engineering departments of universities and centers for professional development of specialists working in the field of innovative production.
Theory of parametric X-ray radiation (PXR) is developed for the case of composite bunch consisting of two fractions of charged particles with different charges and distributions. We suggest PXR as an instrument for the composite bunch diagnostics, for example in case of ion beams in crystal, consisting of two fractures of different ions. Also, for atto-second electron bunches the characteristics of coherent PXR are discussed. © 2015 Elsevier B.V.
Particle flow and reaction plane reconstruction performance using the Projectile Spectator Detector (PSD) in the CBM experiment at the future FAIR facility will be presented. The PSD is a compensating lead-scintillator calorimeter designed to measure the energy distribution of the forward going projectile nucleons and nuclei fragments (spectators) produced close to the beam rapidity. The main purpose of the PSD is to provide experimental estimates of heavy-ion collision centrality and reaction plane orientation. Directed and elliptic proton flow are simulated for Au+Au collisions using five heavy-ion collision event generators: iQMD, UrQMD, DCM-QGSM, LA-QGSM and HSD. Reaction plane reconstruction performance was investigated for produced particles transported with the GEANT Monte-Carlo through realistic CBM detector geometry. Simulations are performed for the range of beam energies between 1 and 30 AGeV, which covers the expected beam energy range of the SIS100 and the SIS300 accelerator rings at FAIR. Results are compared with the experimental data from FOPI, HADES, AGS E877, E895 and STAR. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0).
The Projectile Spectator Detectors (PSDs) for the NA61/SHINE at CERN SPS and the CBM at FAIR, and Zero Degree Calorimeter (ZDC) for the MPD at NICA are discussed. The PSDs and ZDC are compensating lead-scintillator calorimeters designed to measure the energy distribution of the forward going projectile nucleons and nuclei fragments (spectators) produced close to the beam rapidity. Design of the PSD modules, their readout electronics, and calirmeter performance for the collision centrality and reaction plane determination are presented. The PSD module tests with different beams at CERN SPS and results of radiation hardness tests of the avalanche photodiodes used for light readout from the PSD module are also reported. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0).
The results from the investigation of transport characteristics and gas transport asymmetry in bilayer composite membranes are submitted. These membranes are produced by SHS method. Asymmetric effect and hysteresis of permeability in nanoporous membranes are detected. It's shown, that permeability ratio (asymmetry value of permeability) increases up to several times. The asymmetry of permeability usually decreases monotonically with the pressure decrease. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The monitoring of concentration of methane dissolved in water is important for the security of underwater pipelines, delineation of oil and gas fields, and optimization of proper location of oil and gas wells. The reported system consists of metal oxide gas sensor separated from water by hydrophobic pervaporation membrane. Methane MEMS sensor was based on multilayer SiO2/Si3N4 film equipped with platinum heater and coated with sensing layer made of nanoparticle SnO2/Pd (3 wt. %). Methane saturation of water leads to a decrease in sensor resistance by a factor of 6 - 7, the response time of the system is of 200-300 s. © 2015 IEEE.
Coders/decoders that are used in RAM to enhance the data storage reliability on exposure to single nuclear particles are analyzed. If the numbers of check bits are equal, a Hsiao decoder has a lower signal propagation delay than a decoder of the modified Hamming code. A decoder of the extended Hsiao code with additional check bits has the lowest delay among all decoders. When Hsiao decoders with units with a truncated correction circuit, a symmetrically simplified circuit for error vector calculation, and a circuit forming the error signal without the use of the error vector are used in RAM, the critical path lengths and the occupied chip area may be reduced if the detection of triple errors is excluded. The equal efficiency of Richter decoders and coders/decoders obtained through optimization based on genetic algorithms is substantiated for SEC-DAEC codes. © 2015, Pleiades Publishing, Ltd.
Samples of epitaxial structures with GaAs/AlGaAs quantum rings different in morphology are grown by droplet epitaxy. The photoluminescence spectra of the samples are recorded at temperatures of 20–90 and 300 K. Intense peaks defined by quantum confinement of the charge-carrier energy in the quantum rings are observed in the optical region. The peaks are identified by estimating the energy of the ground state of electrons and holes in GaAs quantum rings and by recording the spectra of the samples after removing the layers with the quantum rings by etching. The average dimensions of the quantum rings are determined by atomic force microscopy and scanning electron microscopy. Some inferences about the factors that influence the emission spectrum and intensity of the epitaxial structures with quantum rings are drawn. © 2015, Pleiades Publishing, Ltd.
The photoluminescence spectra of modulation-doped InAlAs/InGaAs/InAlAs heterostructures with quantum wells containing thin strained InAs and GaAs inserts are investigated. It is established that the insertion of pair InAs layers and/ or a GaAs transition barriers with a thickness of 1 nm into a quantum well leads to a change in the form and energy position of the photoluminescence spectra as compared with a uniform Ininf0.53/infGainf0.47/infAs quantum well. Simulation of the band structure shows that this change is caused by a variation in the energy and wave functions of holes. It is demonstrated that the use of InAs inserts leads to the localization of heavy holes near the InAs layers and reduces the energy of optical transitions, while the use of GaAs transition barriers can lead to inversion of the positions of the light- and heavy-hole subbands in the quantum well. A technique for separately controlling the light- and heavy-hole states by varying the thickness and position of the GaAs and InAs inserts in the quantum well is suggested. © 2015, Pleiades Publishing, Ltd.
Temperature behavior of the charge yield and degradation saturation due to the interface precursor depletion has been modeled and simulated. Competition between the time-dependent and true dose rate (ELDRS) effects has been simulated and discussed. © 2015 IEEE.
Silicon carbide thin films were obtained on Si (100) and (111) substrates by means of vacuum laser ablation of α-SiC ceramic target. The influence of substrate temperature on composition, structure and surface morphology of experimental samples was examined using Rutherford backscattering spectrometry (RBS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), conventional and high-resolution transmission electron microscopy (TEM/HRTEM), atomic force microscopy (AFM), selected area electron diffraction (SAED) and X-ray diffraction (XRD) methods. © (2015) Trans Tech Publications, Switzerland.
The electron irradiation effect on hydrogen sensitivity of the integrated sensors based on MISFET has been investigated. The estimation of critical doses has been done according to developed models of hydrogen and radiation sensitivities of MISFET sensors. © 2015 IEEE.
The electron irradiation effect on hydrogen sensitivity of the sensors based on metal-insulator-semiconductor transistor (MISFET) element with structure Pd-Ta2O5-SiO2-Si have been investigated. The MISFET threshold voltage as a function of hydrogen concentration was determined before and after each irradiation. It is found that under irradiation this function was monotonically drifting. In addition after irradiations by doses more than ∼ 700 Gy the hydrogen sensitivity are steadily decreasing. The models of hydrogen and radiation sensitivity were developed. According to represented models the estimations of critical doses and the forecast of hydrogen sensor performance under irradiation have been done. © 2015 The Authors. Published by Elsevier Ltd.
The results of researches of influence of ionizing radiation on the characteristics of integrated hydrogen sensors with MISFIT sensitive elements (TSE) are presented. The proposed compact models of hydrogen and radiation sensitivity take into account the changes of the threshold voltage, the transconductance and ionization currents in the different electrical modes TSE and dose rates of ionizing radiation. It is shown how the electrical modes and types of measurement circuits influence on metrological characteristics of sensors with TSE under the action of ionizing radiation. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The upgraded electrophysical and electrical models of MIS transistor sensitive elements (TSE) are presented for calculating the metrological and performance characteristics of integrated hydrogen sensors and gas-analysis microsystems based on them.
Recently it has been realized that Stone-Wales (SW) defects in graphene are not simple two-dimensional objects but rather involve large vertical displacements of many atoms, resulting in a sinelike shape of the cross section [J. Ma et al., 2009 ]. Customarily, formation of sinelike SW defects is assumed to take place in two steps: 1) an in-plane 90° rotation of two carbon atoms with respect to the center of the C-C bond and 2) transverse shift of those atoms in the opposite direction. Here we show that there is another transformation path that does not go through a flat defect configuration. Following that path results in lower energy barriers for both formation and annealing of sinelike SW defects. © 2015 Elsevier B.V.
The interaction of Stone-Wales topological defects in graphene has been studied through computer simulation. This simulation has revealed configurations of two defects with energies below the energy of a monolayer with two spaced defects. This indicates the attraction between defects and the possibility of the formation of their clusters. The attraction is due to the interference between defect-induced wavy distortions of the structure of the monolayer. In this case, the amplitude of transverse displacement of atoms near a pair of defects reaches 2-3 . Such a strong deformation of graphene by Stone-Wales defects can be one of the reasons for its experimentally observed "crumpled" texture.
The dynamics of a Stone-Wales defect in graphene has been investigated using the computer simulation of its time evolution at different temperatures. The previously predicted thermally activated transitions between two energy-degenerate sinelike configurations of these defects have been directly demonstrated. The temperature dependence of the characteristic time of these transitions has been determined. Based on the analysis of the hypersurface of the potential energy, the activation energy and frequency factor in the Arrhenius law have been obtained.
The heights of energy barriers preventing the formation and annealing of Stone-Wales defects in graphene with a hydrogen atom adsorbed on the defect or in its immediate vicinity have been calculated using the atomistic computer simulation. It has been shown that, in the presence of hydrogen, both barriers are significantly lower than those in the absence of hydrogen. Based on the analysis of the potential energy surface, the frequency factors have been calculated for two different paths of the Stone-Wales transformation, and the temperature dependences of the corresponding annealing times of the defects have been found. The results obtained have been compared with the first-principles calculations and molecular dynamics data.
In tokamaks, plasma emits as a volumetric Soft-X-ray (SXR) source. Emitted X-rays can give very useful information about plasma stability, shape and impurity content. Measuring the Soft X-ray (SXR) radiation ([0.1-20. keV]) of magnetic fusion plasmas is a standard way of accessing valuable information on particle transport and MagnetoHydroDynamic. Generally, like at Tore Supra in France, the analysis is performed with a 2D tomographic system composed of several cameras equipped with detectors like Silicon Barrier Diodes spread in periphery of the tokamak. Unfortunately, the strong constraints imposed by the environment of a tokamak reactor (high neutron fluxes, gamma and hard X-ray emission, high magnetic field and high radiofrequency powers) do not authorize to install in a close vicinity of the machine such detectors. We have thus investigated the possibility of using polycapillary lenses to transport the SXR information to several meters from the plasma, not necessarily in a straight line. The idea is to protect the SXR detector from the entire environment by a proper shielding. Different polycapillary lenses could be used for that purpose and have been tested in collaboration with CELIA (CEA-CNRS) of Bordeaux. Transmission of the order of 20% where observed for the low energetic part of the spectrum (down to 3. keV) while still 10% were observed for the remaining part (from 3 to 10. keV). In parallel a model of polycapillary transmission has been developed and validated against experiment. Results are presented confirming the great potential of polycapillary lenses for SXR transmission in tokamak plasma. Studies of the influence of geometrical parameters like diameter and curvature of the channels, on the photons transmission is also presented. © 2015 Elsevier B.V.
We consider dielectric and magnetic properties of left-handed planar metamaterials with negative permittivity and permeability. In our work we investigate planar metamaterials consist of anisotropic particles. We obtain dependence of permittivity on dielectric polarizability and permeability on magnetic polarizability of the particles. Local field effects are taken into account in calculations. These effects are caused by interaction between single particles. We also obtain the generalized Clausius-Mossotti relations for planar metamaterials made of anisotropic particles in the long wave approximation. We calculate a response function to an external electromagnetic field in case of planar metamaterial. This function describes connection between external electromagnetic field and the local field. On the one hand, such connection allows us to analyze structure of electromagnetic field in the near-field regime. On the other hand, the relationship between the field interacting with particles in the planar metamaterials and the external field is of key importance for calculations of characteristics of the electromagnetic radiation generated by charged particles or particle beams passing through or near the planar structures.
Metamaterials are composite structures that exhibit interesting and unusual properties, e.g. negative refractive index. In this article we consider metamaterials based on colloidal quantum dots (CQDs). We investigate these structures taking into account the local field effects and theoretically analyze expressions for permittivity and permeability of metamaterials based on CdSe CQDs. We obtain inequality describing the conditions when material with definite concentration of CQDs is metamaterial. Also we investigate how the values of dielectric polarizability and magnetic polarizability of CQDs depend on the dots radius and properties the material the quantum dots are made of.
Research on CVL installations with an average power of 20-25 W of cutting and drilling has shown wide range of applications of these lasers for micromachining of metals and a wide range of non-metallic materials up to 1-2 mm. From the analysis indicated that peak power density in the focused light spot of 10-30 μm diameter must be 10sup9/sup-10sup12/sup W/cmsup2/sup the productivity and quality micromachining, when the treatment material is preferably in the evaporative mode micro explosions, followed by the expansion of the superheated vapor and the liquid. To achieve such levels of power density, a minimum heat affected zone (5-10 μm) and a minimum surface roughness of the cut (1-2 μm), the quality of the output beam of radiation should be as high. Ideally, to ensure the quality of the radiation, the structure of CVL output beam must be single-beam, diffraction divergence and have at duration pulses τi = 20-40 ns. The pulse energy should have low values of 0.1-1 mJ at pulse repetition rates of 10-20 kHz. Axis of the radiation beam instability of the pattern to be three orders of magnitude smaller than the diffraction limit of the divergence. The spot of the focused radiation beam must have a circular shape with clear boundary, and a Gaussian intensity distribution. © 2015 SPIE.
Polycapillary lenses are well known optical devices for radiation and charged particles. These lenses consist of thousands channels through which the signal is transmitted by total external reflection phenomenon. Their application have made possible technical improvements in different fields such as imaging, fluorescence analysis, channeling studies etc.[ In particular, the application of this optics coupled with conventional sources such as X-ray tubes has opened a new season for potential applications of desktop instrumentations. For instance, the usage of such lenses has enhanced the spatial coherence and the brilliance over the sample allowing better resolution and contrast for imaging purposes. In addiction, improved focusing power and confocal configuration of other lenses has improved the resolution, from both the energy and the spatial points of view, in fluorescence mapping. A recent work has addressed the behavior of the transmitted radiation through a single capillary in vibrating regime. In this work a test of using a vibrating capillary for stroboscopic imaging is presented. A sample characterized by a known periodic event is studied with a synchronized vibrating capillary.
This work is a part of the RED-100 big project. The aim of the RED-100 experiment is to detect the presently undiscovered coherent neutrino scattering off xenon atomic nuclei. The manufacture of such detectors requires ultrapure materials with very low content of natural radioactive elements. So the pure titanium was selected to assay the uranium and thorium contaminations on 1 ng/g level. In this paper we investigate the possibility of reducing the LOD for LA-ICP-MS analysis by increasing the pulse repetition rate of solid-state laser irradiation up to 4,000 Hz and appropriate adjusting the irradiation power. LODs for U and Th in titanium matrix estimation fell in the sub 10-10 g g-1 level. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Advanced accelerator technology, based on plasma structures, requires high brightness electron beams, which can be used also to drive advanced radiation sources. Indeed, electron beams to be injected into the plasma and accelerated in the plasma channel are characterized by small transverse size and ultra-short time duration, allowing the production of coherent radiation in the THz range. In the present work we report both theoretical and experimental studies on the spatial/angular distribution of Coherent Transition and Diffraction Radiation in the pre-wave zone. © 2015 Elsevier B.V.
We report a new measurement of the midrapidity inclusive jet longitudinal double-spin asymmetry, ALL, in polarized pp collisions at center-of-mass energy s=200GeV. The STAR data place stringent constraints on polarized parton distribution functions extracted at next-to-leading order from global analyses of inclusive deep-inelastic scattering (DIS), semi-inclusive DIS, and RHIC pp data. The measured asymmetries provide evidence at the 3σ level for positive gluon polarization in the Bjorken-x region x>0.05. © 2015 American Physical Society. © 2015 American Physical Society.
The Ti/Al/Ni/Au multilayer metallization system is widespread in the technology of n-GaN-based devices. Herein, the mechanisms of the formation of the surface roughness of the Ti/Al/Ni/Au metallization (with 300 nm hillocks) upon annealing in a nitrogen atmosphere for 30 s at a temperature of 850°C, which creates problems in further lithographic processes, and the ways of overcoming this disadvantage have been studied. The formation of a rough surface during the annealing of a multilayer metallization, associated with the interaction of the constituent metals, has been investigated with the Ti/Al/Ni and Ti/Al/Ni/Au systems. An increase in the sheet resistance of both metallization systems as the annealing temperature is raised can be explained by the interdiffusion of metals and the growing degree of interaction between them with the formation of various intermetallic compounds, exhibiting a far higher specific resistance than that of the initial metals. The X-ray analysis has confirmed the origination of the main NiTi, Al3Ti, and Ni2Al3 intermetallic phases in the Ti/Al/Ni three-layer metallization upon annealing. The surface of the Ti/Al/Ni metallization system has become rougher upon annealing; however, large hemispherical convexes (like those in the Ti/Al/Ni/Au metallization) have not been generated. This has refuted the hypothesis of the balling-up of the molten Al–Ni alloy on the surface of the Ti/Al/Ni metallization. To reduce the amount of an Au–Al liquid phase formed during the annealing, which is the reason that renders the Ti/Al/Ni/Au metallization surface rough, the Au layer thickness was reduced to a minimum, at which the contrast of the metallization elements to the semiconductor surface is sufficient for self-aligning during electron-beam lithography. It has been found that the 50-nm-thick Au layer serves a satisfactory contrast. At such a thickness of the Au layer, the metallization surface morphology improved considerably: the roughness decreased from 300 to 80 nm, and the surface become specular. © 2015, Pleiades Publishing, Ltd.
mu XRF is a powerful instrument for non-destructive characterization of materials of cultural interest. At the XLab Frascati Laboratory this technique is already well performed thanks to the polyCO set equipment allowing simultaneous mu XRF 2D mapping. However, due to the strict demand for in situ analysis in this particular field, a new portable mu XRF spectrometer equipped with a full polycapillary lens conjugated with a transmission anode X-ray tube is proposed. Many cultural objects are characterized by elements (Ag, Sn, etc.) with high energy fluorescence K-lines. Thus, the capability of a full lens to deliver a high energy fraction of X-ray spectrum, in order to excite the fluorescence K-lines of such elements, is tested. (C) 2015 Elsevier B.V. All rights reserved.
Results from experimental designs intended for the creation of a laboratory model of a complex for optical spectroscopy of multiply charged thorium ions with a quadrupole Paul ion trap possessing a linear configuration for the development of a nuclear frequency standard are described. Preliminary experimental studies intended for the production of singly, doubly, and triply charged thorium ions from the solid-state compound thorium nitrate (IV) by the method of electron-beam evaporation are also presented. It is shown that, relative to singly charged ions, with the use of this method the fractions of triply and doubly charged thorium ions exceed the analogous values for the method of laser ablation used to produce these ions in laboratories in the United States and Germany. The method of electron-beam evaporation is made the basis of a newly developed complex for optical ultra-high resolution spectroscopy.
The influence of nano-sized AlAs inserts in the spacer layer AlGaAs on scattering mechanisms of AlGaAs/InGaAs nanoheterostructures has been considered. It was shown that theintroduction of AlAs lead to mobility enhancement up to 20%. The ratio of transport-to-quantum scattering times revealed that in the case of the spacer with AlAs inserts the scattering on ionized Sidonors is strongly decreased in comparison to the spacer without AlAs. © Lietuvos mokslų akademija, 2015.
The influence of nano-sized AlAs inserts in the spacer layer AlGaAs on scattering mechanisms of AlGaAs/InGaAs nanoheterostructures has been considered. It was shown that theintroduction of AlAs lead to mobility enhancement up to 20%. The ratio of transport-to-quantum scattering times revealed that in the case of the spacer with AlAs inserts the scattering on ionized Sidonors is strongly decreased in comparison to the spacer without AlAs. © Lietuvos mokslų akademija, 2015.
ADC/DAC radiation failures are mainly due to radiation-induced degradation of precision parameters of the transfer characteristic such as gain, zero offset, full-scale voltage, integral and differential non-linearity, conversion error. ADC/DAC radiation failure specifics is that even a slight deviation of electrical parameter of internal elements (comparator threshold, internal reference voltage, switch leakage, operational amplifier gain, etc.) often leads to significant degradation of ADC/DAC accuracy. ADC/DAC radiation test procedure and facilities are developed and test results are introduced.
The comparative analysis of radiation behavior for more than 60 types of the transceiver ICs is presented. The most sensitive blocks of transceiver ICs which cause the radiation failures were identified. It was shown that it is possible to identify the production technology of the transceiver IC on the base of analysis of its behavior under irradiation.
A rational methodological approach to the evaluation of the total dose hardness of CMOS microcircuits with respect to low dose rate effects supported by the results of the simulation analysis and experimental studies of a wide range of products is presented. This approach makes it possible to choose the necessary and sufficient amount of radiation researches that provide accurate and informative engineering evaluation of radiation hardness of CMOS microcircuits for use in space hardware.
Mechanisms of resonant nonlinear absorption in the hybrid exciton-plasmon systems based on gold nanoparticles and macroheterocyclical compounds are presented. We used novel substituted subphthalocyanines (SubPc) with 14 pi-electronic system as powerful excitonic 3 - level systems, and 50 nm gold nanoparticles (AuNp) as plasmonic structures. We succeeded to define mechanisms of resonant nonlinearities and to show that local field factor (LFF) and Purcell factor (PF) lead to dramatic enhancement in SubPc nonlinearity. We suggest a theoretical model which describes exciton-plasmon interaction of porphyrin/phthalocyanine related compounds with gold nanoparticles in the resonant high power laser field.
In this work the testing results for the spectrometer with a large sensitive area developed for the crystal monitoring station of modern hadron accelerator control systems used for the beam collimation are presented. The investigations were carried out at the XLab Frascati LNF laboratory aiming mostly in studying the detector sensitivity uniformity throughout the sensor area. © 2015 Elsevier B.V.
A theoretical method is used to find, in an accurate and systematic way, all the possible equilibrium magnetic states of a finite-size one-dimensional chain of classical planar spins, interacting via ferromagnetic nearest-neighbor symmetric exchange and subjected to a uniaxial anisotropy which favors the orientation of the spins along an easy axis within the plane perpendicular to the chain. For a chain with N spins, the energy is a function of N absolute orientation angles (theta(i), i = 1, ..., N) and, owing to the absence of energy competition, the ground state is collinear ferromagnetic and doubly degenerate (either 0(i) = 0 for all i, or 0(i) = pi for all i). The ground state corresponds to a global minimum of the energy in the N-dimensional space, while metastable states correspond to local minima. As a function of N, we have numerically determined the minimal value gamma(min) to be assumed by the ratio gamma between the anisotropy and the exchange constant for the first noncollinear metastable state to appear. For N
We calculate the field of radiation forces in a cylindrical fluid layer on a solid substrate formed as a result of the action on a fluid of a capillary wave propagating from the axis along a free surface. We study the structure of acoustic flows excited by the radiation forces. We discuss the action of flows on small-sized particles and the possibilities of these particles to form ordered structures. © 2015, Pleiades Publishing, Ltd.
X-ray fluorescence analysis is a widely used technique in many applications. Recent advances in X-ray optics, in particular, in polycapillary manufacturing, have allowed achieving microscale spatial resolution, even with conventional sources. Nowadays, many apparatus for X-ray microfluorescence are available. But the majority of them are equipped with experimental chambers, which limit their applicability only to small-sized samples. To overcome this limitation, a new instrument named Rainbow X-Ray (RXR), optimized for large and heavy objects, has been developed at XLab Frascati. Here, we present this unit dedicated to 2D and 3D X-ray microspectroscopy (both mapping and 'colour' tomography), with a resolution between 25 and 75 μm, depending from the incident energy in the range 800eV-25keV. © 2015John Wiley & Sons, Ltd.
An approach is proposed for the quantum-chemical calculation of the structure and fluorescence spectra of exciplexes. The procedure involves the geometry optimization of exciplexes using the CIS method with empirical dispersion correction (CIS-D) and the subsequent single-point calculation of the transition energy using the CIS method with perturbative correction for double excitations (CIS(D)). Calculated fluorescence band positions for exciplexes of (dibenzoylmethanato)boron difluoride with substituted benzenes are in reasonable agreement with the experimental data.
The multireference XMCQDPT2/CASSCF method is used to get insight into the charge transport mechanism of bis(10hydroxybenzo[h]quinolinato)beryllium (Bebq2) and to explain some features of its light absorption and emission in monomeric and dimeric forms. Energy profiles corresponding to electron and hole hopping in Bebq2 monomer and in three close-packed dimers that can occur in the solid phase are calculated. Our calculation revealed that charges and excitons could be either localized on individual ligands or delocalized over a pair of stacking ligands in dimers. Delocalized hole states serve as deep charge traps hindering hole transport. On the other hand, the electron states are localized, and hopping electron transport can take place with low barriers. The excited states of dimers exhibit exciton splitting. In some dimers, the transition dipole moment arrangement is unfavorable for luminescence. Therefore, our calculations explain why Bebq2 is an electron transporter (hole blocker) and why regular packing with ligand stacking in Bebq2 layers favors electron transport along the stacks but decreases luminescence.
Annealing of contact system Ti/Al/Ni/Au for the Ohmic contact formation to the AlGaN/GaN was performed. Method for determining the height of potential barrier in nonrectifying contact using voltage-capacitance characteristic was proposed. Temperature dependencies of the contact resistance for annealed Ti/Al/Ni/Au in temperature range 25÷175°C were obtained. Thermal field emission prevails in rectifying contact, whereas for nonrectifying contact field emission is typical. It is shown that the charge carriers' concentration increase in four times influences on the transition from thermal field emission to field emission. The change of resistance under field emission agrees with the barrier height change. The resulting contact resistance for Ti/Si(6 nm)/Ti/Al/Ni/Au is equal to 0.2 Ω·mm. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The standard model (SM) of particle physics is spectacularly successful, yet the measured value of the muon anomalous magnetic moment (g-2)μ deviates from SM calculations by 3.6σ. Several theoretical models attribute this to the existence of a "dark photon," an additional U(1) gauge boson, which is weakly coupled to ordinary photons. The PHENIX experiment at the Relativistic Heavy Ion Collider has searched for a dark photon, U, in π0,η→γe+e- decays and obtained upper limits of O(2×10-6) on U-γ mixing at 90% C.L. for the mass range 30<mU<90 MeV/c2. Combined with other experimental limits, the remaining region in the U-γ mixing parameter space that can explain the (g-2)μ deviation from its SM value is nearly completely excluded at the 90% confidence level, with only a small region of 29<mU<32 MeV/c2 remaining.
IC's SEE sensitivity may depend on temperature. Traditional ion irradiation methods have some limitations, which laser SEE technique can overcome. In this work, SEE laser test results for various temperatures are discussed. © 2015 IEEE.
Several cases differences SEL sensitivity in IC's with same crystals marking are presented and discussed. The crystals are compared visually and identical crystal markings confirmed. © 2015 IEEE.
Eight selected isomeric amines were ionized using atmospheric pressure chemical ionization and atmospheric pressure photoionization producing a protonated molecule [M+H]+ for each amine. The mobility of these ions was measured by ion mobility spectrometry. The amine compound class was shown to have an important role in mobility separation of the amines. 2,4,6-collidine, N,N-dimethylaniline and N-methyl-o-toluidine with highest observed mobilities have a N-heterocyclic aromatic ring, or are tertiary or secondary amines, respectively, whereas the rest of the compounds with lower mobilities were primary amines. It is suggested that the protonated -NH2 group (-NH3 +) interacts more with the drift gas, and therefore the primary amines have lower mobilities. The effect of the drift gas was tested by mixing argon or helium with the nitrogen drift gas. The presence of argon shifted the mobilities towards lower values, while with helium the mobility shifted towards higher values. However, in neither case did this result in better separation of the unresolved compounds.
Smith-Purcell radiation is a well-known phenomenon, which provides a noninvasive scheme for diagnostics of charged particle beams and is used as an effective source of electromagnetic waves, e.g., in the orotron, the free electron laser, etc. In this paper we develop the theory of Smith-Purcell radiation (SPR) for the little-investigated case of arbitrary angles between the charged particle trajectories and the rulings of a grating. The effect of conical diffraction arising here changes drastically the space distribution of the radiation. By contrast to the only existing approach, described by Haeberle et al. [Phys. Rev. E 55, 4675 (1997)], which requires difficult numerical calculations, we give a fully analytic theory of SPR. Also, in this paper we present for the first time the theory of x-ray Smith-Purcell radiation. Evanescent waves on the surface are shown to lead to strong enhancement of Smith-Purcell radiation, through a resonant mechanism. The results are important for the description of real divergent high-brightness beams and for the development of novel noninvasive diagnostic schemes based on the Smith-Purcell effect.
When light is scattered on a grating, the scattered waves are distributed over a cone surface, which is called "conical diffraction effect". In the present work the similar effect in theory of diffraction radiation (DR) from a charged particle moving near a target at some angle to its edge is predicted and described for the first time. The equation describing the surface of maximal radiation, which is conical surface, is derived from the first principles. The effect is illustrated by spectral-angular distributions of DR from a thin target (screen) in X-ray, EUV, optical and lower frequency regions for two cases: (a) the particle moves in the plane perpendicular to the screen; (b) the particle moves in the plane parallel to the screen. The radiation for these two orientations of the target is shown to differ mainly in direction of mirror reflection to the trajectory of the particle. Due to similar nature of DR and transition radiation (TR) the same effects should arise for TR from targets of limited transversal size. (C) 2015 Elsevier B.V. All rights reserved.
Diffraction radiation from divergent beam is considered in terms of radiation in UV and X-ray range. Scedastic form of Gaussian distribution of the particle in the bunch, i.e. Gaussian distribution with changing dispersion has been used, which is more adequate for description of divergent beams than often used Gaussian distribution with constant dispersion. Both coherent and incoherent form-factors are taken into account. The conical diffraction effect in diffraction radiation is proved to make essential contribution in spectral-angular characteristics of radiation from a divergent beam. (C) 2015 Elsevier B.V. All rights reserved.
Absorption in the medium, i.e. an imaginary part of the dielectric permittivity, can lead to arising of Cherenkov radiation at high frequencies - X-Ray and XUV. In this paper X-Ray Diffraction radiation from a bunch of ultra-relativistic electrons moving near an absorbing target is investigated theoretically. In these conditions the Cherenkov radiation arises even when trajectories of the particles does not cross the target. The spatial distribution of the radiation usually represents the cone with the axis in forward direction with thickness proportional to the imaginary part of dielectric permittivity. In this paper it is shown that taking into account the refraction and reflection of the waves at the surface of the target leads to essential changes in spatial distribution of radiation. We give analytical description of the XUV Cherenkov and diffraction radiation from the bunch of charged particles. We show that the spatial distribution of radiation is not symmetrical in relation to the top face of the target.
The effect of sediment flotation was observed in dispersion of graphene oxide flakes with Ag-particles deposited thereon in the aqueous-organic (containing dimethylformamide) under the visible light action, with subsequent stabilization of the dispersion, which does not occur in the absence of Ag-particles. The main reason for this laser light induced movement of sediment graphene oxide flakes may be associated with the appearance of small bubbles. The further development of this approach seem to be able to estimate the of graphene flakes photoactivity with different activating particles. © 2016 SPIE.
The nanofiltration of the water-ethanol mixture of different compositions at three pressure drops through a nanoporous membrane based on poly(1-trimethylsilyl-1-propyne) has been experimentally and theoretically studied. A mathematical model of the onset of flow has been proposed, and the percolation threshold depending on the physicochemical and geometrical characteristics of the membrane system has been found. The model suggests gradual membrane pore opening with an increase in pressure and alcohol concentration in the mixture and can take account of the distribution of alcohol molecules over the cross section of the membrane pores. The theoretical results agree well with the experimental data. © 2015 Pleiades Publishing, Ltd.
A method for improving the efficiency of using laser radiation (LR) energy is discussed to implement high levels of dose rates by reducing the radiation wavelength. Generally, the optimal range of LR energy for the simulation of the transient radiation response in CMOS SOS/SOI microcircuits depends on the technological characteristics of production and ranges from 0.9 to 0.75 ?m.
A discharge plasma system for neutron generation based on the concept of inertial electrostatic confinement is considered. The system is made in the form of a gas-filled (1–60 Pa) diode with a composite hollow cathode placed at its center symmetrically to an embracing hollow cylindrical anode. Preionization of the discharge gap and an original design of the electrode system with a transparent central part make it possible to initiate a pulse high-voltage (100–150 kV) volume discharge in the ion oscillation mode. Estimates of the neutron emission in such a deuterium-filled diode show the feasibility of generating a pulse with a neutron yield on the order of 105 in the reaction D(d, n)3He, which is confirmed in experiments with an optimized geometry of the electrodes.
A method is proposed for concentrating in different output flows in a square cascade with two additional extractions the components of the multicomponent isotopic mixture being separated. The parameters of the proposed cascade, a square cascade with additional extraction, and a cascade with flow expansion at internal steps on condition that the number of separative elements in them is the same are compared for the separation of a mixture of tungsten isotopes. It is shown that the proposed cascade expands the possibilities of previously known methods of concentrating intermediate-mass isotopes, since several target products can be obtained at the same time in the output flows.
The five-flow cascade to enrich recycled uranium with simultaneous its dilution with low-enriched uranium and waste uranium is proposed. The results of computational experiments show that the proposed cascade has the advantages in the consumption of natural uranium value of the separation work in comparison to both the previously proposed multi-flow cascades, and the standard cascade to enrich natural uranium. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Elastically stressed metastable GeSn layers with a tin molar fraction as large as 0.185 are grown on (001) Si and GaAs wafers covered with a germanium buffer layer. A set of wafers with a deviation angle in the range 0 degrees-10 degrees is used. It is established that the GeSn crystal undergoes monoclinic deformation with the angle beta to 88 degrees in addition to tetragonal deformation. Misorientation of the wafers surface results in increasing efficiency of the incorporation of tin adatoms into the GeSn crystal lattice. Phase separation in the solid solution upon postgrowth annealing of the structures begins long before the termination of plastic relaxation of elastic heteroepitaxial stresses. Tin released as a result of GeSn decomposition predominantly tends to be found on the surface of the sample. Manifestations of the brittle-plastic mechanism of the relaxation of stresses resulting in the occurrence of microcracks in the subsurface region of the structures under investigation are found.
Experimental results of single event transients in FPGA under ion and focused laser beam irradiation are presented. Abnormal time duration of single event transients in FPGA under ion beam was observed.
We have investigated the multilayer adsorption isotherms of styryl dyes (SDs) of pyridine series (dications) with active centers (COOH) of the surface of polystyrene colloidal particles in an aqueous solution, depending on the length of N-substituent and the particle diameter. A proposed model of sorption takes into account both the ion-exchange sorption mechanism (exchange of H+ ions to SD dications) and a phase equilibrium shift of SD solution to multilayer ionic condensate in the ionic diffusive layer near the electric charged surface of the particles if the concentration of the SD solution is high enough. Modeled sorption isotherms are in agreement with the experimental data. © 2015, Pleiades Publishing, Ltd.
The specific features of the photoluminescence and the electrical properties of doped nanoheterostructures containing a composite InAlAs/InGaAs/InAlAs quantum well with a thin InAs insert in the middle are studied. The insert thickness is varied in the range from 1.7 to 3.0 nm. It is established that the position of the peaks in the photoluminescence spectra in the photon energy range 0.6-0.8 eV correlates with the InAs insert thickness. Simulation of the band structure shows that the experimentally observed variation in the energy of optical transitions is associated with lowering of the energy of electron and hole states in the quantum well with increasing insert thickness. In the photon energy range 1.24-1.38 eV, optical transitions in the region of the InAlAs buffer-InP substrate interface are observed. The signal photon energy and intensity depend on the features of the formation of this heterointerface and on the conditions of substrate annealing. It is conceived that this is due to the formation of a transition region between the InAlAs buffer and the substrate.
Statistics and correlation analysis method based on stable distributions is presented. Method can be applied to the estimation of the influence of one data set to another with respect to the rare events. In carbon fibers data analysis method allows one to estimate influence of the different defect types on the carbon fiber strength and the influence of the mechanical properties of the carbon fiber on the early stages of conversion on the mechanical properties on the latter stages. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Three different states of a dispersed nonwetting liquid (water) in the Fluka 100 C8 and Fluka 100 C18 disordered porous media, as well as transitions between these states under variation of the temperature and the degree of filling, have been revealed. It has been shown that the appearance of such states is due to the broadening of the pore size distribution function f(R), fluctuations of configurations of neighbors in the system of pores and fluctuations in the configuration of a pore and its environment consisting of filled and empty pores in the percolation cluster. These states and transitions are caused by the competition between the effective repulsion of the nonwetting liquid from the wall of the pore, which is responsible for the "extrusion" of the liquid from the pore, and the effective collective "multiparticle" attraction of the liquid cluster in the pore to clusters in the neighboring connected pores. The observed difference in the behavior of the Fluka 100 C8/water and Fluka 100 C18/water systems and the previously studied Libersorb-23 (L23)/water system indicates a significant dependence of the state of these systems on the type of disorder in them. © 2015 World Scientific Publishing Company.
Mean and partial cross-section concepts and their connections to multiplicity and statistics of multiple cell upsets (MCUs) in highly-scaled digital memories are introduced and discussed. The important role of the experimental determination of the upset statistics is emphasized. It was found that MCU may lead to quasi-linear dependence of cross-sections on linear energy transfer (LET). A new form of function for interpolation of mean cross-section dependences on LET has been proposed.
A CMOS DICE (Dual Interlocked Storage Cell) cell consists of two transistor groups whose layout on the crystal increases the cell’s stability against the impact of single nuclear particles. A fault of the cell’s state does not take place if the particle impacts transistors of one group only. The topological layouts of basic memory elements with a different relative position of two transistor groups of 28 nm CMOS DICE cells were designed and analyzed. Different cell layouts with a distance between the sensitive pairs of transistors of two groups of 1, 2, and 3 µm and a set of basic memory elements for designing memory arrays of static RAM with increased stability with respect to state faults due to the particle track charge separation between two transistor groups of the cell were proposed. The area of the DICE cells is larger by a factor of 2.1–2.5 than that of sixtransistor cells with transistors of the same size. © 2015, Pleiades Publishing, Ltd.
Trigger transistors of the DICE CMOS memory cell can be divided into two groups and spaced topologically; and if the effect of single nuclear particle affects transistors of only one group, no upset of the cell state occurs, while the cell transforms into the unsteady state. If transistors of the second group are simultaneously affected, and this effect exceeds the threshold one, then the upset of the initial state occurs. If the effect on the second group is lower than the threshold one, then the cell returns to the initial steady state from an unsteady one. Characteristics of the DICE CMOS memory cell with a 28-nm design rule are simulated and analyzed for unsteady states caused by the influence of a single nuclear particle on transistors of only one or both groups of cell transistors. © 2015, Pleiades Publishing, Ltd.
A complex investigation of structural and electrical properties of Ininf0.52/infAlinf0.48/infAs/Ininfy/infGainf1 − y/infAs/Ininf0.52/infAlinf0.48/infAs nanoheterostructures on InP substrates containing thin InAs and GaAs inserts in a quantum well (QW) has been performed. The GaAs nanolayers are grown at the QW boundaries between InGaAs and InAlAs layers, while the double InAs inserts are grown in InGaAs layers symmetrically with respect to the QW center. The layer and interface structures have been studied by transmission electron microscopy. It is shown that, when using the proposed epitaxial growth conditions, the introduction of ∼1.2-nm-thick InAs nanoinserts into the InGaAs QW and a ∼1-nm-thick GaAs nanobarrier at the QW boundaries does not induce structural defects. The diffusion of the InAlAs/InGaAs interface (2–3 monolayers) and InAs/InGaAs nanoinsert interface (1–2 monolayers) has been estimated. Measured Hall mobilities and electron concentrations in structures with different combinations of InAs and GaAs inserts have been analyzed using calculated energy band diagrams and electron density distributions. It is found that the photoluminescence spectra of the structures under study have differences caused by specific structural features of coupled QWs (specifically, the change in the In molar fraction due to InAs inserts and the change in the QW thickness due to GaAs transition barriers. © 2015, Pleiades Publishing, Inc.
Fine-grained powder crystal phosphors SrTiOinf3/inf:Prsup3+/sup and SrTiOinf3/inf:Prsup3+/sup, Al have been investigated. Their photoexcitation, luminescence, and photoconductivity spectra have been recorded. It is found that only one center (PrinfSr/inf sup·/sup) is responsible for the luminescence in SrTiOinf3/inf:Prsup3+/sup, while the luminescence in SrTiOinf3/inf:Prsup3+/sup, Al is due to two centers: (AlinfTi/inf′ PrinfSr/inf sup·/sup)sup×/sup and PrinfSr/inf sup·/sup. A mechanism of energy transfer upon luminescence excitation from the (AlinfTi/inf′ PrinfSr/inf sup·/sup)sup×/sup center is proposed. © 2015, Pleiades Publishing, Ltd.
The identification of single clusters in the electronic signals produced by ionizing particles within a drift chamber is expected to significantly improve the performances of this kind of detectors in terms of particle identification capabilities and space resolution. In order to develop refined cluster recognition algorithms, it is essential to measure the response of the chamber and its electronics to single ionization clusters. This can be done by irradiating the chamber with X-rays. We report here on the studies performed on a drift chamber prototype for the MEG-II experiment at the X-ray facility of the INFN Frascati's National Laboratories "XLab Frascati". The prototype is operated with a helium-isobutane mixture and instrumented with high bandwidth custom pre-amplifiers. The results of this study have been used to develop an innovative method for cluster recognition, based on the Wiener filter technique, which has been tested on data collected at the Frascati's Beam Test Facility. As a side measurement, we also performed a study of the gas gain in a configuration which is similar to that of the MEG-II experiment.
Hopping transport of charge carriers in thin (up to 100 nm) organic layers, which are suitable for organic light-emitting diodes and solar cells, is modeled in the framework of Gaussian disorder model. Drift mobility dependence within ranges of layer thickness, energy disorder and field strength is considered. Monte-Carlo simulations for low concentration case show weak dependence on type of lattice - simple cubic, body-centered and face-centered lattice. Results of this work are compared with the results obtained recently by Cottaar et al., done within master equation approach. The comparison shows the deviation at low disorder. Additionally we take into account influence of barrier-limited injection in case of cubic lattice.
We synthesized bulk polycrystalline samples of metastable phases of Sbinf2/infTeinf3/inf and Biinf2/infTeinf3/inf topological insulators by rapid quenching after a high-pressure-higherature treatment at P = 3.7-7.7 GPa; T = 873 K and found superconducting transitions with TinfC/inf; suponset/sup = 2 K and 6 K, respectively. A low critical current value of about 2 mA in the metastable Sbinf2/infTeinf3/inf phase and an absence of the detectable heat capacity effect at the superconducting transition indicated a low-dimensional character of superconductivity. A zero-field magnetic susceptibility cusp and linear positive magnetoresistance indicate a topological insulator state. © 2015; Elsevier B.V. All rights reserved.
The new superconducting heterofullerides with the composition AnGaxC60 and AnGaxMyC60 (A = K, Rb; n = 1, 2; M = In, Sn, Bi; x, y < 1) were synthesized by a new method of reactions of liquid alloys (alkali metal with gallium or gallams) with a solution of fullerene in the organic solvent at temperature 110-120 °C. Temperature dependence of the magnetic susceptibility was measured in the temperature interval from 4.2 K to 100 K and transitions to the superconducting state were detected at temperatures Tc ranged from 7 K to 25 K. New superconducting fullerides RbGaxC60 and RbGaxInyC60 with orthorhombic crystal lattice were discovered. © 2015 Elsevier Ltd.
Abstract For the first time, the effect of asymmetry of the membrane transport was studied for organic solvents and solutes upon their nanofiltration through the plasma-modified membranes based on poly(1-trimethylsilyl-1-propyne) (PTMSP). Plasma treatment is shown to provide a marked hydrophilization of the hydrophobic PTMSP surface (the contact angle of water decreases from 88 down to 20sup°/sup) and leads to the development of a negative charge of - 5.2 nC/cmsup2/sup. The XPS measurements prove the formation of the oxygen-containing groups (Si-O and C-O) due to the surface modification. The AFM images show that the small-scale surface roughness of the plasma-treated PTMSP sample is reduced but the large-scale surface heterogeneities become more pronounced. The modified membranes retain their hydrophilic surface properties even after the nanofiltration tests and 30-day storage under ambient conditions. The results of the filtration tests show that when the membrane is oriented so that its modified layer contacts the feed solution, the membrane permeability for linear alcohols (methanol-propanol) and acetone decreases nearly two times. When the modified membrane surface faces the permeate, the membrane is seen to regain its transport characteristics: the flux becomes equal to that of the unmodified PTMSP. The well-pronounced effect of the transport asymmetry is observed for the solution of the neutral dye Solvent Blue 35 in methanol, ethanol, and acetone. For example, the initial membrane shows the negative retention for the Solvent Blue 35 dye (- 16%) upon its filtration from the ethanol solution whereas, for the modified PTMSP membrane, the retention increases up to 17%. Various effects contributing to the asymmetry of the membrane transport characteristics are discussed. © 2014 Elsevier B.V.
Desorption/ionization on silicon (DIOS) is widely used in modern mass spectrometry for obtaining ions of various organic substances. The high efficiency of DIOS suggests that it may be a promising method in ion-mobility spectrometry (IMS) using gas-phase ion separation. The influence of laser wavelength and intensity on DIOS of trinitrotoluene (TNT) molecules under ambient conditions has been studied. If laser with a wavelength of 266 or 355 nm is used, TNT molecules predominantly form (TNT - H)- negative ions. Their formation has been found to result from laser-induced proton transfer from TNT molecules to the porous silicon (pSi) surface, rather than gas-phase ion-molecule reactions. The dependence of the yield of (TNT - H)- ions on the laser intensity has been analyzed. The ion yield curve has been demonstrated to fit the Arrhenius function at laser intensity lower than ∼2.5×107 W/cm2. Experiments have shown that the desorption/ionization of TNT molecules is not a purely thermal process. The results demonstrate that DIOS can be widely used in the IMS technology. © 2015 American Chemical Society.
The electronic absorption spectra of the symmetric cyanines exhibit dramatic dependence on the conjugated chain length: whereas short-chain homologues are characterized by the narrow and sharp absorption bands of high intensity, the long-chain homologues demonstrate very broad, structureless bands of low intensity. Spectra of the intermediate homologues combine both features. These broad bands are often explained using spontaneous symmetry-breaking and charge localization at one of the termini, and the combination of broad and sharp features was interpreted as coexistence of symmetric and asymmetric species in solution. These explanations were not supported by the first principle simulations until now. Here, we employ a combination of time-dependent density functional theory, a polarizable continuum model, and Franck-Condon (FC) approximation to predict the absorption line shapes for the series of 2-azaazulene and 1-methylpyridine-4-substituted polymethine dyes. To simulate inhomogeneous broadening by the solvent, the molecular structures are optimized in the presence of a finite electric field of various strengths. The calculated FC line shapes, averaged with the Boltzmann weights of different field strengths, reproduce the experimentally observed spectra closely. Although the polarizable continuum model accounts for the equilibrium solvent reaction field at absolute zero, the finite field accounts for the thermal fluctuations in the solvent, which break the symmetry of the solute molecule. This model of inhomogeneous broadening opens the possibility for computational studies of thermochromism. The choice of the global hybrid exchange-correlation functional SOGGA11-X, including 40% of the exact exchange, plays the critical role in the success of our model. (Graph Presented). © 2015 American Chemical Society.
Effect of laser plasma reverse extension is described in this paper. Influence of the effect on ion acceleration in a laser ion source is researched. This effect leads to sedimentation of ions on metal target, which significantly impacts acceleration time of other ions. In this case, the ions also tend to travel major part of their path with constant velocity. This allows one to consider movement of the ions in plasma drift space, when optimizing time focusing ability of the TOF analyzer. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
There are proposed and implemented a new physical model of pulse evaporation, generation, and expansion of laser plasma. The model takes into account the complex physical processes occurring in the laser plasma. To overcome the difficulty of describing the entire complex of processes, the step by step method used. At each time step, all processes are described by linear functions, and the relationship between them, as the sum of linear transformations. The model is implemented for the multicomponent plasma, in which impurity elements have different degrees of ionization. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The prospects for creation of the new type of laser time of flight mass spectrometer were described. The mass spectrometer is based on usage of a reflecting wedge-shaped mirror as an analyzer of the ions by masses. The analyzer provides time focusing ion by both energy and initial angle divergence of ions from the source. Time focusing is carried out for the ±20% energy range, what is at least 2 times more, than for known ion-optical systems for similar usage. The resolution of the mass analyzer is ∼850 for extremely small overall dimensions (∼10×l0×5 cm). © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
A new approach to the formation of ultrashort laser ion packages in the ion source of a time-of-flight (TOF) mass spectrometer for elemental analysis is described. This is achieved by installing a wedge-shaped reflector with special correcting plates. The reflector provides time and space focusing of the ion packages. Such time focusing allows the reduction of the ion package duration up to ins. The proposed approach allows more than an order of magnitude increase in the resolution of the laser TOF mass spectrometer with an axially symmetric electrostatic analyzer to 10,000-13,000. In this Letter the theoretical calculations justifying the proposed method are presented.
The sampling unit of the device, based on ion mobility spectroscopy technique, for detection of ultra small (trace) substances concentration on human fingers and documents is described. The vapor pressure of many dangerous substances is very small; so the heating of an investigated surface is needed for effective detection. However the direct heating of the human fingers by irradiation of the gas-discharge lamp is not effective because a small concentration of the melamine (pigment of the black or brown color) in the skin of the human palm. Therefore in this work the combination of the two methods is used: a grid is heated by the irradiation of the gas-discharge lamp and a grid heats the surface of the finger which is pressed to a grid. © 2015 The Authors. Published by Elsevier Ltd.
We have studied the dependence of azimuthal anisotropy v2 for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of v2 as a function of transverse momentum pT and centrality in Au+Au collisions at sNN=200 and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in v2 values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that v2 depends both on eccentricity and the number of participants, Npart. We observe that v2 divided by eccentricity () monotonically increases with Npart and scales as Npart1/3. The Cu+Cu data at 62.4 GeV falls below the other scaled v2 data. For identified hadrons, v2 divided by the number of constituent quarks nq is independent of hadron species as a function of transverse kinetic energy KET=mT-m between 0.1<KET/nq<1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of v2/(nq··Npart1/3) vs KET/nq for all measured particles. © 2015 American Physical Society.
We present a systematic study of charged-pion and kaon interferometry in Au+Au collisions at sNN=200 GeV. The kaon mean source radii are found to be larger than pion radii in the outward and longitudinal directions for the same transverse mass; this difference increases for more central collisions. The azimuthal-angle dependence of the radii was measured with respect to the second-order event plane and similar oscillations of the source radii were found for pions and kaons. Hydrodynamic models qualitatively describe the similar oscillations of the mean source radii for pions and kaons, but they do not fully describe the transverse-mass dependence of the oscillations. © 2015 American Physical Society.
In this paper, we describe a novel cost-effective and simple technology for the production glass MEMS applied as microhotpalte platform for metal oxide gas sensors. The basis of the technology is magnetron sputtering of platinum heating layer followed by precise laser engraving and cutting used for heater patterning. As a result of the technology, we demonstrate the glass microhotplate cantilever with thickness of 30 μm equipped with platinum microheater with dimension of about 500×500 μm. The cantilever type MEMS microhotplate demonstrate very high stability at working temperatures up to 600 °C, which gives possibility to use it for the low-scale fabrication microhotplate of metal oxide gas sensors. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The temperature control system for the study of single event disruptions produced by hard ion impacts in integrated circuits is described. Heating and cooling of the irradiated device are achieved using thermoelectric modules (Peltier modules). The thermodynamic performance of the system is estimated. The technique for the numerical estimation of the main parameters of the temperature control system for cooling and heating is considered. The results of a test of the system in a vacuum cell of an accelerator are presented.
The temperature dependence of single-event upset multiplicity in 65 nm CMOS SRAM was investigated in this paper. Experimental results show significant increase of upset multiplicity over a temperature range of 300 to 400 K. Main physical mechanisms leading to the increase of the multiplicity of upsets at elevated temperatures were studied using three-dimensional (3-D) device simulations. A major role of upset voltage decrease and temperature dependence of the parasitic bipolar effect was established. Simulation results can be used for maximal upset multiplicity estimation.
Samples with arrays of GaAs/AlGaAs quantum rings (QRs) of different shapes were grown by molecular beam epitaxy in droplet epitaxy mode. Photoluminescence (PL) spectra of the samples were measured at 20 90 K and 300 K, intense peaks attributed to the QR layers were observed. The peaks were identified by comparison of as-grown and selectively etched samples and by the calculation of the ground state energy for charge carriers in GaAs QRs. FWHM narrowing with the temperature increase was observed below 70 K.
The paper presents test results of electronic components candidate for spacecraft obtained on low (3-6 MeV/nucleon) and high (20-40 MeV/nucleon) energy heavy ion test facilities. In addition to obtaining experimental data, the purpose of the study was to demonstrate the availability of such high-energy facilities in Russia, by comparing the test results with earlier data, obtained on the same devices at a low energy facility. The interest of these facilities, definition of the operation conditions, possible errors and limitations are highlighted. © 2015 IEEE.
Performance of the gas-filled detector prototypes based on the GEM, TGEM, and Micromegas technologies was studied with the aim of selecting variants for tracking detectors of the muon system for the CBM Experiment. The study was performed on the test beam of the proton accelerator at the Petersburg Nuclear Physics Institute (PNPI). Three-component mixtures based on Ar and He were used as the working gas. For all tested detector prototypes, the detection efficiencies were measured, and the modification of the amplitude spectra as a function of the incident beam intensity was investigated. © 2015, Pleiades Publishing, Inc.
Currently axially symmetric type of analyzer with an electrostatic sector fields (AESF) is rarely used to construct time-of-flight mass spectrometers. The main drawback, hindering the wider use of the analyzers of this type, is the lack of chromatic second-order focusing by energy. However, the configuration of AESF in combination with orthogonal accelerator (OA) allows to achieved it through compensation of energy aberrations of the analyzer in the system of orthogonal input of the ion beam. In the presented work the results of theoretical calculation, simulation and experimentally obtained data are compared. Characteristics of the analyzer with OA in a large extent depend on the parameters of the incoming ion beam. Data of modeling the 2nd stage of gas-dynamic interface, which have the greatest influence on the parameters of the ion beam, is provided. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The article describes the automated complex of parametric and functional control of the wide range of industrial transceivers IC's by using PXI family of National Instruments equipment. The capabilities of the designed system are observed as well as the software. © 2015 IEEE.
AnAs a result of analyzing more than 60 types of the modern transceivers ICs, the most sensitive functional units and the critical operation modes upon exposure the space radiation (especifically, TID and SEE effects) were identified. © 2015 IEEE.software. © 2015 IEEE.
AnAs a result of analyzing more than 60 types of the modern transceivers ICs, the most sensitive functional units and the critical operation modes upon exposure the space radiation (especifically, TID and SEE effects) were identified. © 2015 IEEE.software. © 2015 IEEE.
The perspectives for the increase in the accuracy of optical frequency standards by means of the development of "nuclear clocks"-a novel frequency standard based on the nuclear transition to the long-living isomer nuclear state of thorium-229 with energy -7.6 eV are discussed. Theoretical estimations give a possible accuracy Av/v -1x10-20, that allows wide scope of applications for a frequency standard, from satellite navigation systems to experimental verification of the principles of the general theory of relativity. The results are presented and the future prospects for research are discussed on the measurement of the isomeric transition in the nucleus of thorium-229 and creation on its basis the frequency standard of the new generation. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
This paper presents the evaluation results of the specialized ICs packages (100-and 144-ceramic packages) using proton and electron accelerators and Monte-Carlo (forward and reverse/adjoint) simulation. Proton and electron results are verified by forward Monte-Carlo modelling and the packages shielding effectiveness is calculated for a wide-range space radiation environment (5 orbits from low-earth orbit to geostationary orbit) and different spacecraft shielding thicknesses using reverse/adjoint Monte-Carlo method. © 2015 IEEE.
The main circuit design and constructive-Topological SRAM cells Radiation-Hardening-By-Design (RHBD) methods applied in 250. 90 nm bulk CMOS processes were analyzed. The test chip research results show that an increase of the 6T-memory cell area by 1.5 times can significantly improve the tolerance to all the radiation factors. The CMOS SRAM 4 Mbit, 16 Mbit chips and IP-blocks as part of ASIC were designed and implemented in 250. 90 nm bulk CMOS processes using the considered RHBD methods. © 2015 IEEE.
Manifestation of the dose rate effects is strongly depends on the laser polarization direction for the ICs, which technology is less than the laser wavelength. There are several approaches to reduce this influence in deep-submicron ICs. © 2015 IEEE.
Numerical and experimental evaluation of the influence of laser radiation polarization orientation on ionization response of 180-nm and 90-nm CMOS ICs is performed. Comparative research is carried out to determine how the polarization of various sized laser beams affects the parameters of IC ionization response. The necessity of considering the orientation of laser radiation polarization for laser local radiation effect simulation is shown.
The research is focused on the differences in radiation behavior for transistors of different geometry, body tie contact types, device layer thickness and biasing.
The influence of thermolysis time on the absorption spectra of partially thermally dehydrochlorinated polyvinyl chloride in acetophenone solution is studied. Strong increase in the optical density Dsupλ/sup of the dehydrochlorinated PVC samples is caused by the increasing amount Nsup-C=Crossed D signi-/sup and the length of chains of conjugated double bonds of carbon-C = C-. It is noted that the optical density Dsupλ/sup first increases linearly with dehydrochlorination time and then reaches saturation. The estimation of amount of double conjugated carbon bonds in 1ml versus thermolysis time t is given, which varies between Nsup-Crossed D signi=Crossed D signi-/sup = 4·10sup17/sup-7.4·10sup18/sup for t from 40 to 420 minutes. The effective capture cross section of a photon on conjugated double bonds of carbon for dehydrochlorinated PVC solution in acetophenone is estimated, which was about 10sup-17/sup cmsup2/sup. The analysis is done of the absorption curves «red» shift to longer wavelengths with growth of Nsup-Crossed D signi=Crossed D signi-/sup upon increase of thermolysis time. It is noted that the dependence of the optical density on the wavelength in this range is well described by a simple exponential function. © 2016 SPIE.
The validity of MIL STD 883 H test method at dose rate less than 10 mrad(Si)/s is discussed. The prediction capability of conversion model is evaluated at ultra-low dose rates in comparison with standard MIL-STD-883-H. © 2015 IEEE.
The anomalous magnetic moment of the muon is one of the most precisely measured quantities in experimental particle physics. Its latest measurement at Brookhaven National Laboratory deviates from the Standard Model expectation by approximately 3.5 standard deviations. The goal of the new experiment, E989, now under construction at Fermilab, is a fourfold improvement in precision. Here, we discuss the details of the future measurement and its current status. (C) 2015 AIP Publishing LLC.
In this work ion mobility time-of-flight mass spectrometry is preliminarily studied as a method for identification of the composition for triphenylmethane ball point pen dyes by their traces on paper. Components were identified as Basic violet 2, Methyl violet 6B, Methyl violet 2B, Crystal violet. All the compounds were shown to form excellent individual mass selective mobility peaks. Short time of analysis allow one to consider IMS/TOFMS as a perspective alternative for traditional methods of identification. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The NUCLEON satellite experiment is designed to investigate directly, above the atmosphere, the energy spectra of cosmic-ray nuclei and the chemical composition from 100 GeV to 1000 TeV as well as the cosmicray electron spectrum from 20 GeV to 3 TeV. NUCLEON is planned to be launched in 2014. This mission is aimed at clarifying the essential details of cosmic-ray origin in this energy interval: number and types of sources, identification of actual nearby sources, and the investigation of the mechanisms responsible for the knee. Specific features of the NUCLEON instrument are relatively small thickness and small weight. A special method of energy determination by the silicon tracker was developed for this case. In this paper we describe a design of the instrument and the results of accelerator beam tests in terms of charge and energy resolution. The overall evidences of the capability of the apparatus to achieve the declared aims are also presented.
The NUCLEON satellite experiment is designed to investigate directly, above the atmosphere, the energy spectra of cosmic-ray nuclei and the chemical composition (Z=1-30) at energy range 100 GeV - 1000 TeV. The effective geometric factor is more than 0.2 m2sr for nuclei and 0.06 m2sr for electrons. The satellite was launched in 26 December 2014. The planned exposition time is more than 5 years.
The NUCLEON satellite experiment is designed to investigate directly, above the atmosphere, the energy spectra of cosmic-ray nuclei and the chemical composition (Z= 1 - 30) at energy range 100 GeV- 1000 TeV. The effective geometric factor is more than 0.2 msup2/supsr for nuclei and 0.06 msup2/supsr for electrons. The planned exposition time is more than 5 years. © Owned by the authors, published by EDP Sciences, 2015.
Modern standards of the microwave security based on complex methods of measurement and calculation of the parameters of electromagnetic field (EMF) and absorbed dose in the living tissues. However, the movement of biological object, the complex structure of living tissues, the temporal and spatial variability EMF create uncertainty of these measurements and evaluations. In addition, current standards do not take into account the effect of weak electromagnetic radiation on physiological parameters and human health, particularly in terms of its professional liability business. Furthermore many research have shown that the weak radiation has an individual and cumulative character. But, today simple technique for the operational control of the personal dose characteristics is absent. © 2015 International Union of Radio Science (URSI).
This paper summarizes the design results for the read-out ASIC for the space NUCLEON project of the Russian Federal Space Agency ROSCOSMOS. The ASIC with a unique high dynamic range (1-40 000 mip) at low power consumption (< 1.5 mW per channel) has been developed. It allows to record signals of relativistic particles and nuclei with charges from Z = 1 up to Z > 50, generated by silicon detectors, having capacitances up to 100 pF. The chip structure includes 32 analog channels, each consisting of a charge sensitive amplifier (CSA) with a p-MOS input transistor (W = 8 mm, L = 0.5 μm), a shaper (peaking time of 2 us) and a T&H circuit. The ASIC showed a 120 pC dynamic range at a SNR of 2.5 for the particles with minimal ionization energy (1 mip). The chip was fabricated by the 0.35 um CMOS process via Europractice and tested both at lab conditions and in the SPS beam at CERN. © 2015 IOP Publishing Ltd and Sissa Medialab srl.
The main purpose of this work is to intensify and to improve the efficiency of water treatment processes as well as to combine optimally modern techniques and technological devices in water treatment processes. Offered comprehensive hybrid water treatment developing technology of different origin is based on the combination of the treatment by reagent and membrane electro dialysis. In offered technology, of water treatment as a reagent is proposed to use alumino-silicic reagent, which simultaneously is coagulant, flocculant and adsorbent. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The technique for estimation of the chip temperature of integrated circuits during irradiation is described. The technique is based on the experimental determination of the actual value of junction-To-Ambient thermal resistance. © 2015 IEEE.
X-ray Bragg ptychography (XBP) is an experimental technique for high-resolution strain mapping in a single nano-and mesoscopic crystalline structures. In this work we discuss the conditions that allow direct interpretation of the ptychographic reconstructions in terms of the strain distribution obtained from the two dimensional (2D) XBP. Simulations of the 2D XBP experiments under realistic experimental conditions are performed with a model of InGaN/GaN core-shell nanowire with low (1%) and high (30%) Indium concentrations in the shell.
A stack of five metastable 200-nm-thick elastically strained GeSn epitaxial layers separated by 20-nm-thick Ge spacers was grown on (001) Si/Ge virtual substrate by MBE. The molar fraction of Sn in different layers varied from 0.005 to 0.10, increasing with the layer distance from the Ge buffer. The phase separation of the GeSn alloy during postgrowth annealing takes place along with plastic relaxation. The phase separation begins well before the completion of the plastic relaxation process. The degree of phase separation at a given annealing temperature depends strongly on the Sn content in the GeSn alloy. The Sn released from the decomposed GeSn alloy predominantly accumulates as an amorphous layer on the surface of the sample. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The results of quantum-mechanical calculations of elementary prismanes—hexaprismane Cinf12/infHinf12/inf and octaprismane C16H16—have been presented. Their stability has been investigated in terms of the density functional theory and nonorthogonal tight-binding model, and the heights of potential barriers preventing isomerization and decay have been determined. It has been established based on the analysis of the molecular dynamics data and the hypersurface of the potential energy of these metastable compounds that hexaprismane and octaprismane have a rather high kinetic stability, which indicates the possibility of the formation of carbon polyprismanes for applications in microelectronics and nanoelectronics, power engineering, pharmaceutics, metrology, and information technologies. © 2015, Pleiades Publishing, Ltd.
Radiation from non-central electrons moving through channel with variable radius in the THz region is investigated using Particle In Cell (PIC) solver of the Computer Simulation Technology (CST) software package. Characteristics of radiation arising for non-central and central electrons propagation in the channel are compared, both for Smith-Purcell and Cherenkov kinds of radiation. It is demonstrated that the radiation is more intensive for the non-central propagation of electrons.
Concepts regarding the mechanism of radioactive decay of nuclei are developed on the basis of a hypothesis that there is a dynamic relationship between the electronic and nuclear subsystems of an atom, and that fluctuating initiating effects of the electronic subsystem on a nucleus are possible. Such relationship is reflected in experimental findings that show the radioactive decay of nuclei might be determined by a positive difference between the mass of an initial nucleus and the mass of an atom's electronic subsystem, i.e., the mass of the entire atom (rather than that of its nucleus) and the total mass of the decay products. It is established that an intermediate nucleus whose charge is lower by unity than the charge of the initial radioactive nucleus is formed as a result of the above fluctuating stimuli that initiate radioactive decay, and its nuclear matter is thus in an unbalanced metastable state of inner shakeup, affecting the quark subsystem of nucleons. The intermediate nucleus thus experiences radioactive decay with the emission of α or β particles. At the same time, the high energy (with respect to the chemical scale) of electrons in plasma served as a factor initiating the processes in different nuclear chemical transformations and radioactive decays in low-temperature plasma studied earlier, particularly during the laser ablation of metals in aqueous solutions of different compositions and in near-surface cathode layers upon glow discharge. It is shown that a wide variety of nucleosynthesis processes in the Universe can be understood on the same basis, and a great many questions regarding the formation of light elements in the solar atmosphere and some heavy elements (particularly p-nuclei) in the interiors of massive stars at late stages of their evolution can also be resolved. © 2015 Pleiades Publishing, Ltd.
Due to constant changes in the composition of the atmosphere, the human has a need to provide themselves with a necessary content of available oxygen for breathing. Particularly strong impact on the atmosphere was exerted by the advent of the technological revolution. Human activity started affecting the atmosphere at the beginning of the XIX century due to the development of heavy industry. Smog is a widespread problem of the contemporary world, which is connected with the industry development, manufactures, mankind activity. The problem of smog has not been solved in many countries yet. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
In this paper we consider X-Ray and EUV Transition radiation propagating in backward direction which is generated by the ultrarelativistic electron bunch crossing the target. The target consists of periodical set of thin wires with the rectangular cross-section. We obtain the analytical expressions for distribution of the energy of the transition radiation per solid angle and frequency. In high frequency region (X-Ray, EUV), where the wavelength of radiation is less than length of a beam, the main part of radiation is incoherent. In this case the radiation from electron bunches is described by the so called incoherent form-factor. We obtain and analyse the expression for incoherent form-factor. In this work we show that incoherent form-factor arises always when the size of a target is finite and that it depends on the ratio between the transversal size of the bunch and the production of wavelength and Lorentz-factor of the charged particles. The coherent effects of target and the electron bunch play an important role in increasing the intensity of radiation and also change the spatial distribution of radiation.
The installation and the measurement data procedure were established for the sorbent characteristics determination. Sorption isotherms of the three gases (nitrogen, oxygen and carbon dioxide) are obtained on the industrial zeolites NaX, NaX-BKO and NaA in a pressure range (0;7) bar. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
This paper presents a brief overview of total ionizing dose effects for a variety of PLL ICs and PLL-based frequency synthesizer implemented in commercial bulk CMOS, silicon-on-insulator CMOS, BiCMOS and SiGe BiCMOS technology processes with frequency range up to 8 GHz. Total dose sensitivity data of PLL ICs have been obtained at the SPELS test center, based on comprehensive parametric and functional control. © 2015 IEEE.
The model of transient multicomponent mass transfer in a Q-cascade is developed. It enables to study the physical regularities of alteration of concentrations along the cascade stages and in the product flow from the cascade. The capability of the developed model is demonstrated by calculation of the transient process and the time-to-steady-state in a gas centrifuge cascade for separation of krypton isotopes.
In this work it is experimentally showed that transmission of atmospheric drift tube ion mobility spectrometer (DT-IMS), connected with mass spectrometer (MS), depends on ion mobility of investigated compounds, because of depletion effect of Bradbury-Nielson ion gate (IG), which previously has been approved only by standalone DT-IMS. Theoretical estimation of depletion width of IG is in good agreement with experimental data. Also it is found, that ion lost due to its pulsing work of IG are few times smaller, than its duty cycle. It's explained by difference in influence of coulomb repulsion at 100% and 1% duty cycle-in first case it's significant versus second case, when coulomb repulsion become negligibly small, that reduces lost of ions on entrance of MS interface. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Energy transfer from nanostructures to biological supramolecular photosystems is an important fundamental issue related to the possible influence of nanoobjects on biological functions. We demonstrate here two-photon-induced Forster resonance energy transfer (FRET) from fluorescent CdSe/ZnS quantum dots (QDs) to the photosensitive protein bacteriorhodopsin (bR) in a QD-bR hybrid material. The two-photon absorption cross section of QDs has been found to be about two orders of magnitude larger than that of bR. Therefore, highly selective two-photon excitation of QDs in QD-bR complexes is possible. Moreover, the efficiency of FRET from QDs to bR is sufficient to initiate bR photoconversion through two-photon excitation of QDs in the infrared spectral region. The data demonstrate that the effective spectral range in which the bR biological function is excited can be extended beyond the band where the protein itself utilizes light energy, which could open new ways to use this promising biotechnological material. (C) 2015 Optical Society of America
The paper revealed the using of industrial production equipment ALTI "Karavella-1", "Karavella-1M", "Karavella-2" and "Karavella-2M" precision components of IEP production [1-4]. The basis for the ALTI using in the IEP have become the positive results of research and development of technologies of foil (0.01-0.2 mm) and thin sheets (0.3-1 mm) materials micromachining by pulsed radiation CVL [5, 6]. To assess the micromachining quality and precision the measuring optical microscope (UHL VMM200), projection microscope (Mitutoyo PV5100) and Carl Zeiss microscope were used. © 2015 SPIE.
The article discusses the use of a NI PXI-7841R module to control the operation of VLSI microprocessors in terms of radiation experiment. The article also discusses the use of the NI PXIe-7962R module in conjunction with the module NI PXI-7841R to expand measurement system possibilities. © 2015 IEEE.
Magnetic resonance is examined in paramagnetic systems with a small concentration of spins. The free induction signal (FIS) and resonance line shape function (LSF) are calculated. The theory is based on the introduction of an auxiliary system where one spin does not have a flip-flop interaction with the surroundings. The FIS is calculated for this spin using the Anderson-Weiss-Kubo theory and its memory function is used to construct the memory of the main system. The needed numerical coefficients are obtained from expansions of the FIS in terms of the concentration. Here the polarization transport in magnetically dilute systems is taken into account for the first time. This is shown to lead to significant slowing down of the decay in the FIS for times longer than the phase relaxation time. Existing experimental data are compared with theoretical models. Satisfactory agreement is obtained for the description of the central part of the LSF after an additional experimentally observed broadening is introduced in the theory. Data on the amplitude and position of the sideband peaks from the different experiments are not in good agreement with one another or with the theory. (C) 2015 AIP Publishing LLC.
A simple semi-analytical solution is proposed for the verification of numerical codes for modelling of unsteady gas flows in strong centrifugal fields. The gas flow is driven by a source/sink of energy and by an external force (deceleration/acceleration of the gas rotation) acting on the gas at a given frequency. In the semi-analytical solution, the rotor is infinite, while the given forces vary harmonically with a given wave-length along the axial coordinate. As a result, the unsteady flow problem is reduced to a system of ordinary differential equations, which can be quickly solved to any prescribed accuracy. A similar unsteady problem is solved numerically with the rotor length equal to the wavelength of the external force along the axis of rotation. The periodicity of the solution is prescribed at the end faces of the rotor. As an example, the semi-analytical solution is compared with the numerical ones obtained with different boundary conditions and mesh resolution in radial direction. The comparison confirms that the problem formulations are equivalent in both cases. The semi-analitical solution allows us to determine optimal mesh resolution and accuracy of the calculations.
This paper is aimed at studying the influence of high temperature annealing on the films of silicon oxynitride, obtained by reactive magnetron sputtering of silicon in the environment of argon, nitrogen and oxygen. Annealing of the films was performed in nitrogen atmosphere within temperature range of 800-1200C. The chemical composition of obtained films and their properties were studied and their dependence on annealing temperature was shown. The recommendations on application of high temperature annealing in formation process of dielectric membrane structures for sensitive elements of semiconductor gas sensors were developed. © 2015 The Authors.
The aim of the paper is the research of dielectric membrane films obtained by reactive magnetron sputtering. Simulation of temperature distribution on the membrane structures of different elemental composition in the process of heating and cooling was carried out. The manufacturing results and the results of the properties study of dielectric membrane films are presented. The qualitative analysis of membrane films stability to destruction and deformation in the process of heating and cooling is given. Optimum element compositions and formation modes of dielectric films for sensitive elements of semiconductor gas sensors are determined. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The new dielectric membrane structure for sensitive elements of semiconductor gas sensors is presented. The new fabrication technology of the sensitive elements based on the membrane structure is given. The main feature of the technology is the separation of anisotropic etching of silicon into two stages. The preference etchant compositions and the preference elemental composition of membrane films to obtain mechanically relaxed membranes are presented. The membrane structures were fabricated and their properties were studied. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The nature of absorption bandshapes of dibenzoylmethanatoboron difluoride (DBMBFinf2/inf) dye substituted in ortho-, meta-, and para-positions of the phenyl ring is investigated using DFT and TDDFT with the range-separated hybrid CAM-B3LYP functional and the 6-311G(d,p) basis set. The solvent effects are taken into account within the polarized continuum model. The vibronic bandshape is simulated using a time-dependent linear coupling model with a vertical gradient approach through an original code. For flexible chromophores, the spectra of individual conformers are summed up with Boltzmann factors. It is shown that the long-wavelength absorption bandshape of DBMBFinf2/inf derivatives is determined by three factors: the relative statistical weights of conformers with different electronic absorption patterns, the relative position and intensity of the second low-energy electronic transition, and the vibronic structure of individual electronic peaks. The latter is governed by the relationship between the hard vibrational modes, which contribute to vibronic progression, and soft modes, which provide broadening of the peaks. The simulated spectra of the dyes in the study are generally consistent with the available experimental data and explain the observed spectral features. This journal is © the Owner Societies.
The article presents the results of computational and experimental studies of supersonic flow around a cube arbitrary oriented relative to the direction of the incoming flow. Supersonic flow visualization around the cubical objects was performed by two methods: computational based on the complete NavierStokes equations averaged by Reynolds which are enabled in the SolidWorks engineering and on the experimental - using the shadow photography. © 2015, National Research Nuclear University. All rights reserved.
A new technique to perform the analysis of multiphase fluid flow based on wave dispersive X-ray absorptiometry is suggested. The numerical simulation and comparison of this technique with currently used approaches are provided and a way to increase the luminosity intensity is found that includes the usage the X-ray focusing optics by a bent crystal and a polycapillary semilens. Based on numerical simulation of radiation spectrum the influence of the bent crystal on the luminosity is evaluated and experimentally shown the advantages of using the multicapillary optics.
In this work, we demonstrated an open access Wi-Fi wireless digital platform for environmental gas monitoring based on different types of gas sensors with SPI digital output. The digital platform consist space for four sensors. Used for data exchange between drivers of gas sensors and wireless digital platform, the open data exchange protocol for digital intellectual sensors (DIS) gives possibility to work with any type of gas sensors (electrochemical, metal oxide, thermocatalytic, optical etc.). Developed system architecture of wireless digital platform has also an advantage "hot swap" (PnP) of gas sensors. Visualization of gas concentrations from the wireless digital platform is possible to be received on-line through any web application available on most mobile device (laptop, smart phone, etc.) using widely available free internet browsers (Opera, Google Chrome, etc.) without necessity of downloading any additional user or service software. © 2015 IEEE.
This paper relates the X-ray micro-Computed Tomography and micro X-ray Fluorescence 2D mapping of a synthetic emerald performed by a conventional X-ray source matched with polycapillary optics. The investigated crystals were synthesized in 1888 by Hautefeuille and Perrey starting from a stochiometric oxide mixture and using LiMoOinf4/inf as a flux; Cr was added to the system to give the green-color to the resulting crystals. Preliminary scanning electron microscope-backscattered electron images, coupled with wavelength-dispersive spectrometry microanalyses, showed a peculiar 'hourglass' distribution of Cr across the beryl crystals. In this contribution, we show the capability of a laboratory polycapillary lenses/X-ray tubes layout to characterize at the micrometric scale; the 3D spatial distribution of Cr in these emerald crystals. Actually, this technique offers many opportunities to characterize natural and technological materials where zoning of particular chemical elements occur at the micron or sub-micron scale. © 2015John Wiley & Sons, Ltd.
We present here the angular distribution of the radiation propagated inside MultiChannel Plates with micro-channels of ~3. μm diameter. The spectra collected at the exit of the channels present a complex distribution with contributions that can be assigned to the fluorescence radiation, originated from the excitation of the micro-channel walls. For radiation above the absorption edge, when the monochromatic energy in the region of the Si L-edge hits the micro-channel walls with a grazing angle θ ≥. 5°, or at the O K-edge when θ ≥. 2° a fluorescence radiation is detected. Additional information associated to the fine structures of the XANES spectra detected at the exit of MCPs are also presented and discussed.
The problem of non-identity in characteristics of the GCs for uranium isotope separation grows up with increase of a rotor speed of rotation. It may lead to noticeable decrease of the separative power of the centrifugal machines. The carried out assessments allowed to get the dependence of the relative separation performance losses on the non-identity in the hydraulic characteristics of the GCs connected in parallel. The results of calculation are compared with that of obtained in experiments. © 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
The PHENIX Collaboration has measured φ meson production in d+Au collisions at sNN=200 GeV using the dimuon and dielectron decay channels. The φ meson is measured in the forward (backward) d-going (Au-going) direction, 1.2y2.2 (-2.2y-1.2) in the transverse-momentum (pT) range from 1-7 GeV/c and at midrapidity y0.35 in the pT range below 7 GeV/c. The φ meson invariant yields and nuclear-modification factors as a function of pT, rapidity, and centrality are reported. An enhancement of φ meson production is observed in the Au-going direction, while suppression is seen in the d-going direction, and no modification is observed at midrapidity relative to the yield in p+p collisions scaled by the number of binary collisions. Similar behavior was previously observed for inclusive charged hadrons and open heavy flavor, indicating similar cold-nuclear-matter effects. © 2015 American Physical Society. ©2015 American Physical Society.