bluuebunny/crossref_metadata_2025_split huggingface dataset:
In-situ WAXS study of the crystal structure of R-BAPB oligoimide during heating
Authors: Ivan’kova E M , Kasatkin I A , Popova E H , Didenko A L , Vaganov G V , Yudin V E , Komarov P V 
Published: December 2020

Abstract
In the process of this work, an oligoimide FT-BAPB-R-BAPB-FT was synthesized, the particles of which consist of numerous lamellas having a semi-crystalline structure. On the DSC thermogram of oligoimide powder, two endo peaks were observed at 281.1°C and 306.4°C. A unique WAXS experiment was performed in-situ by heating the reactor oligoimid powder in a heat chamber. There was no significant difference in the X-ray profiles when the sample was heated. It should be noted that the transformation of the crystalline cell does not occur until the sample melts. It was revealed that the degree of crystallinity decreases during heating. We believe that the low-temperature endopeak is associated with the melting of small crystallites and amorphization of the sample. However, a significant increase in crystal size was found to be a result of recrystallization. Thus, the high-temperature endopic corresponds to the melting of larger crystallites.
The effect of imidization conditions on the structure and properties of fibres from partially crystallized polyimide
Authors: Vaganov G V , Didenko A L , Ivanov A G , Ivan’kova E M , Yudin V E , Borisov I L , Volkov A V 
Published: December 2020

Abstract
In this work, the two-stage process for producing polyimide fiber from polyamic acid (PAA) by wet spinning was used. Polyimide fibers were obtained by thermal and chemical imidization. The effect of the imidization method (chemical and thermal) on morphology, chemical structure, thermal stability and mechanical properties of polyimide fibers was investigated. A number of research methods were used in the work, such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calometry (DSC), thermogravimetric analysis (TGA) and determination of strength characteristics.
TEM investigation of microstructure of semipolar GaN layers grown on nano-patterned Si(001) substrates
Authors: Myasoedov A V , Bert N A , Bessolov V N 
Published: December 2020

Abstract
The synthesis of III-nitride binary compounds on commercial standard (001) silicon wafers by vapour-phase epitaxy is one of the promising directions for III-nitride technology development. However, the difference between crystal symmetry of Si(001) and wurzite (0001) surface structures is challenge that hinders the development. A use of silicon substrates with nano-patterned surface is one of the solutions to the problem. In this paper we present a transmission electron microscopy study of polar and semipolar GaN layers grown by halide vapour-phase epitaxy and metalorganic vapour-phase epitaxy on nano-patterned silicon (001) substrate. Crystallographic orientation relationships between the silicon substrate and GaN layers is identified. For GaN layers grown by metalorganic vapour-phase epitaxy an effect of SiC buffer layer synthesized by original growth method on their microstructure and surface morphology is under consideration.
Microstructure and morphology of 2D arrays of Ge quantum dots in a Si/Al2O3 matrix
Authors: Sokura L A , Nevedomskiy V N , Baidakova M V , Levin A A , Belolipetsky A V , Yassievich I N , Ershov A V , Bert N A 
Published: December 2020

Abstract
The paper presents the results of the microstructure and morphology study of two-dimensional Ge QD arrays in a Si/Al2O3 matrix formed by annealing multilayer periodic structures with Ge nanolayers in a Si/Al2O3 matrix. The distinctive features of samples in the series are the location and thickness of the Si barrier layers between Ge and aluminium oxide matrix. X-ray reflectometry and diffractometry and transmission electron microscopy studies have shown that large Al6Ge5 crystallites are formed and the multilayer structure is destroyed after annealing of the multilayer sample Al2O3/Ge without Si. It was found that the presence of Si barrier layers in multilayer Al2O3/Si/Ge structures reduces the interdiffusion of Al and Ge, but Ge1-xSix nanocrystallites are formed as a result of Si and Ge interdiffusion. Thus, the introduction of Si barrier layer into the Al2O3/Ge structure allowed obtaining of two-dimensional arrays of Ge1-xSix nanocrystallites with the penetration of Si up to 0.64.
Production and reconstruction of short-lived ρ(770)0, K*(892)0, ϕ(1020) and Λ(1520) resonances as a function of centrality and energy in Au+Au collisions at NICA
Authors: Ivanishchev D , Kotov D , Malaev M , Riabov V , Ryabov Yu 
Published: December 2020

Abstract
The short-lived resonances have proved to be very useful in the study of heavy-ion collisions at SPS, RHIC, and the LHC. Properties of these particles measured in dominant hadronic decay channels carry a wealth of information about the hadron chemistry and reaction dynamics. Resonances containing one or two strange quarks contribute to the study of the strangeness enhancement phenomenon predicted as a signature of the phase transition to quark-gluon plasma in heavy-ion collisions. Resonance integrated and differential yields are sensitive to the hadron re-scattering and regeneration in the hadronic phase. The resonance production has only scarcely been studied in heavy-ion collisions at NICA energies. These proceedings are devoted to the review of the expected properties of the resonances and their sensitivity to different stages of Au+Au collisions at

s

N
N

= 11 GeV. Results of feasibility studies for reconstruction of ρ(770)0, K*(892)0, ϕ(1020) and Λ(1520) resonances in the MPD experimental setup as a function of collision energy and centrality are presented.
Luminescence of silicon and quartz crystals at mechanical destruction
Authors: Vettegren V I , Ponomarev A V , Mamalimov R I , Scherbakov I P , Kulik V B 
Published: December 2020

Abstract
Spectra and time dependencies of fractoluminescence (FL) signals of silicon (Si) and quartz (SiO2) crystals are obtained when diamond crystals are scratched on their surfaces. Signals are generated when barriers preventing dislocation movement along sliding planes are broken. Simultaneously, the Si and SiO2 crystals break down into nanocrystals (nc). The band 1.62 eV and 2.14 eV corresponds in FL spectra of Si and SiO2 nc accordingly. After the crystals are broken, powders are formed. The size of Si and SiO2 nc in powders was determined by photoluminescence (PL) and Raman spectroscopy.
The possibility of controlling the relaxation rate of color centers in the optical fibers
Authors: Dmitrieva D S , Pilipova V M , Dudkin V I , Davydov V V , Rud V Yu 
Published: December 2020

Abstract
The necessity of method developing for losses compensation in the fiber optic communication lines after irradiation is substantiated. The reasons of appearance of radiation color centers in the optical fiber, which are the main sources of losses in irradiated fiber, are considered. The different methods of the governance of color centers relaxation rate after γ-radiation influence to the optical fiber are researched A method of the relaxation processes rate increasing of color centers is developed. It’s using allows to compensate the negative influence of γ-radiation on the fiber optic communication line of the during data transmission. The received experimental results are presented.
The role of excited discrete atomic states in the formation of quantum vortices in barrier-suppression ionization of hydrogen-like atom by ultrashort laser pulse
Authors: Larionov N V , Smirnovsky A A 
Published: December 2020

Abstract
We theoretically examine the quantum vortices creating through barrier-suppression ionization of two dimensional hydrogen atom by ultrashort laser pulse. We show that for the considered case of ionization, the excited discrete atomic states do not impact on the vortex formation, and the problem can be considered in the single-level atom approximation.
Digital holographic visualization of microparticles retained by an optical spatial trap
Authors: Shostka N V , Sokolenko B V , Karakcheva O S , Prisyazhniuk A V , Voytitsky V I , Poletaev D A , Halilov S I 
Published: December 2020

Abstract
We propose a convenient method for generating optical traps based on a spatially structured beam. The proposed method of optical trap shaping utilizes interference of few Gaussian beams which waists, inclination angles and beam number are chosen for controllable trapping of micron-sized particles in three-dimensional space. In addition to implementing non-contact trapping, optical visualization in all planes was performed with digital holographic microscopy. This method contributes to the accurate localization of the studied specimens inside the cuvette over whole volume.
Effect of saturable absorber in 1.5 μm wafer-fused vertical cavity surface-emitting lasers
Authors: Blokhin S A , Bobrov M A , Maleev N A , Blokhin A A , Vasyl’ev A P , Kuzmenkov A G , Ustinov V M , Gladyshev A G , Babichev A V , Novikov I I , Karachinsky L Ya , Voropaev K O , Ionov A S , Egorov A Yu 
Published: December 2020

Abstract
The static characteristics of 1.5 μm wafer-fused VCSEL with the thin n++-InGaAs/p++-InGaAs/p++-InAlGaAs tunnel junction (TJ) were investigated. The devices with the 8 μm diameter of the buried tunnel junction (BTJ) demonstrate effective single-mode lasing. A rapid increase in the threshold current, accompanied by an abrupt change in the output optical power is observed for devices with BTJ-diameter less than 7 μm. The observed behavior can be explained by increasing in the overlap of the optical mode with the unpumped (passive) part of the active region, which leads to the additional optical absorption. On the one hand, since the high-order transverse modes have the higher optical losses due to larger overlap with the unpumped part of the active region, then lasing via fundamental mode is more preferable even at large size of BTJ region. On the other hand, the reduction of effective index step between the BTJ region and the regions outside BTJ (caused by using small TJ etching depth) and the lateral smoothing of the difference in the height of the surface relief after TJ regrowth results in the significant drop of the transverse optical confinement factor and rise of absorption. Moreover, the absorption effect can be also strongly enhanced by increasing the heatsink temperature due to decreasing in the gain-to-cavity detuning.
Temperature dependence of the optical and electrical properties of long-wavelength InAsSb-based LED heterostructures
Authors: Semakova A A , Romanov V V , Moiseev K D , Bazhenov N L , Mynbaev K D 
Published: December 2020

Abstract
Optical and electrical characteristics of asymmetrical InAs/InAsSb/InAsSbP LED heterostructures with the InSb content in the active layer of 0.15 and 0.16 were studied in the temperature range 4.2 -300 K. At T < 150 K, radiative transitions involving donor-acceptor states in the InAs substrate were observed in electroluminescence spectra, and the presence of these states also showed up in the peculiarities of current-voltage characteristics. A strong effect of the quality of the InAsSb/InAsSbP heterointerface on the characteristics of the heterostructures was observed.
Visual control and data transmission system by Li-Fi technology for patients in a vegetative state/unresponsive wakefulness syndrome and minimally conscious state
Authors: Degtiareva S A , Kondratieva E A , Smirnova I G , Polukhin I S , Andreev Y S , Bougrov V E 
Published: December 2020

Abstract
Due to the development of high technologies, there is a need to use computer systems to support the increasingly complex types of human activities. It provides high accuracy and speed of various research and medical examinations. Taking into account the daily workload of doctors in the Intensive Care Unit, remote medical diagnostics systems are being implemented in many referral hospitals to predict the course of diseases. Decision-making is the result of processing certain information, the medical history patients based on the use of accumulated knowledge. Therefore, it can be concluded that automatic and visual control systems make the diagnosis process more accurate and easier. The aim of the work is to develop an optoelectronic system for visual monitoring and data transmission for patients in a coma by Li-Fi technology.
Spectrum evolution of magnetostatic waves excited through ultrafast laser-induced heating
Authors: Filatov Ia A , Gerevenkov P I , Wang M , Rushforth A W , Kalashnikova A M , Khokhlov N E 
Published: December 2020

Abstract
We study experimentally the influence of the laser-induced temperature gradient on the parameters of propagating magnetostatic surface waves in thin film of the ferromagnetic metallic alloy Galfenol Fe0.81Ga0.19. The material has a pronounced magnetocrystalline anisotropy and exhibits the long-distance propagation of magnetostatic surface waves excited with femtosecond laser pulses. The excitation pulse heats up the sample locally, what leads to the spatial-temporal change of magnetization and anisotropy parameters of the film, and thus excites the magnetostatic surface waves. We show experimentally that the spectrum of the excited waves narrows as they propagate in such a gradient medium. By changing the orientation of external magnetic field with respect to anisotropy axes of the sample, we control whether the low- or high-frequency part of the spin waves spectrum is suppressed.
Structural and dielectric properties of ceramic and thin film multiferroics based on Ba0.5Sr0.5TiO3
Authors: Mylnikov I L , Burovikhin A P , Eskov A V , Dedyk A I , Pavlova Yu V , Belyavskiy P Yu , Semenov A A 
Published: December 2020

Abstract
This paper presents the results of a study of the structural and dielectric properties of barium-strontium titanate (Ba0.5Sr0.5TiO3) with a high concentration of doped manganese ions. It was found that upon the addition of manganese ions, the phase transition point shifts toward lower temperatures. A graph of the dependence of the ceramic lattice parameters on the concentration of manganese ions is presented. It is shown that with an increase in the sintering temperature of ceramics, the dielectric constant of the samples increases.
Micro-photoluminescence of InP/GaInP2 quantum dots structures for topological quantum gates
Authors: Afanasev K M , Vlasov A S , Lebedev D V , Mintairov S A , Kalyuzhnyy N A , Saly R A , Zadiranov Yu M , Mintairov A M 
Published: December 2020

Abstract
Self-organized quantum dots (QD) InP/GaInP2 are natural electronic molecules (EM). They are promising objects for the study of the physics of strongly correlated electronic systems and the creation of quantum logic elements. In this work, we used micro-photoluminescence technique to study the effect of molecular oxygen on emission properties of these QDs and possible reducing their surface density.
Gaussian impurity bands in GaN and weakening of carrier confinement in InGaN/GaN quantum wells
Authors: Bochkareva N I , Ivanov A M , Klochkov AV , Shreter Y G 
Published: December 2020

Abstract
Gaussian impurity bands in GaN responsible for intracenter optical absorption and photoluminescence, give rise to defect-assisted carrier tunneling (hopping) through the barriers in the pn nanostructures with InGaN/GaN quantum wells (QWs). The tunneling injection of majority cariers into the QW results in the current humps and in rapid increase in the radiative recombination efficiency at low enough forward bias. As the bias increases, the carrier confinement in the QW weakens, leading to tunneling injection of minority cariers into the barriers, which results in the emission efficiency saturation and droop.
Experimental studies of the spectral characteristics of a free glow discharge in the wavelength range of 340-440 nm
Authors: Bezverkhnii N O , Monakhov N A , Petrenko M V , Lapushkina T A , Sakharov V A , Poniaev S A , Bobashev S V 
Published: December 2020

Abstract
Non-equilibrium air plasma generated in free glow discharge is characterized by optical emission spectroscopy techniques in the wavelength range of 340–440 nm. The rotational and vibrational temperature are studied as a function of distance from the electrode, to find out differences in the distribution of plasma parameters along with the discharge axis. In this work, the rotational and the vibrational temperature is determined from rovibrational spectra of second positive N2 system. It is observed that

N
2
+

/

N
2

intensity ratio increases from anode to cathode along the discharge axis.
The properties of long-lived ions appearing in plasma diode in a course of nonlinear oscillations
Authors: Bakaleinikov L A , Kuznetsov V I , Flegontova E Yu 
Published: December 2020

Abstract
Nonlinear oscillations may occur in a plasma diode when the ions are reflected from a potential barrier. It was found that long-lived ions are formed in the course of the oscillations of the potential. Based on the proposed analytical model of the oscillations of the potential the reason for the appearance of long-lived ions is elucidated and the main features of their distribution function are revealed. The analytical results are in good agreement with the results of simulation.
Prediction of drag crisis on a circular cylinder using a new algebraic transition model coupled with SST DDES
Authors: Stabnikov A S , Garbaruk A V 
Published: December 2020

Abstract
Flows with massive separation zones are frequent in industrial applications and pose a considerable challenge for contemporary turbulence solving techniques. Accurate prediction of these types of flows can be broken down into two distinct problems: prediction of separation points, which can be addressed by using laminar to turbulent transition models in RANS framework and description of the separated regions, best dealt with by using LES. The present work proposes a new algebraic transition model which is then coupled with the hybrid RANS-LES method DDES with the resulting approach tested on a flow around a circular cylinder on a wide range of Reynolds numbers ranging from sub- to super-critical. Results show that the proposed method is an improvement relative to both RANS and DDES methods and shows promise but requires further development.
Numerical simulation of the interaction of uranium hexafluoride with methane and oxygen in turbulent flame
Authors: Popov P A , Talalov V A , Pashkevich D S , Kambur P S , Kapustin V V , Zimin A R , Alekseev Yu I 
Published: December 2020

Abstract
Model of the uranium hexafluoride conversion in a methane-oxygen turbulent diffusion flame is presented. Model of the weighted sum of grey gases was used to calculate the absorption coefficient of mixture of uranium dioxide particles and carbon dioxide. Radiation heat transfer model was calibrated using available experimental data. A good agreement was obtained between the simulation results and experimental data.
Influence of destruction of the bismuth crystal structure on the features of measuring pulsed heat fluxes using a sensor based on anisotropic thermoelements
Authors: Popov P A , Poniaev S A , Sakharov V A , Reznikov B I , Monakhov N A 
Published: December 2020

Abstract
The results of heat flux measurements using a sensor based on anisotropic thermoelements with defects in the crystal structure during reflection of a shock wave are presented. Using numerical simulation, the influence of the defective layer thickness on the sensor electrical signal and the calculated heat flux is analysed. It is shown that the presence of even a thin defect layer makes it unsuitable for measuring pulsed heat fluxes with a characteristic time of ∼ 1 μs.
Ultrasound temperature control during short-term local heating of a test object by focused ultrasound
Authors: Ivanova Y F , Yukhnev A D , Gataulin Y A , Smirnov E M , Tarkhov D A , Berkovich A E 
Published: December 2020

Abstract
High Intensity Focused Ultrasound (HIFU) is widely used in modern medicine. One of the important applications is the ablation of internal organ tumors under the HIFU heating. During this procedure, it is necessary to monitor the temperature in healthy adjacent tissues. Ultrasound thermometry (UST) is a promising non-invasive method of temperature control. The paper presents implementation of the UST technique in case of short-term local heating. A new algorithm suggested for ultrasound data processing improves the accuracy of the ultrasound thermometry technique to 2 °C.
Testing of a new algebraic laminar-turbulent transition model on a range of airfoils at moderate Reynolds numbers
Authors: Matyushenko A A , Stabnikov A S , Garbaruk A V , Menter F R , Lechner R 
Published: December 2020

Abstract
High quality prediction of laminar-turbulent transition for flow around airfoils is an important task for industrial applications. Prediction of such flows is usually carried out using the RANS framework in combination with transition models. The present study shows the capability of a recently developed algebraic transition model for prediction flows around different airfoils. The results of the model demonstrate satisfactory agreement with the experimental data and with results of existing differential models.
Monte Carlo simulation of mercury ion drift characteristics in an inert gas
Authors: Kurbanismailov V S , Maiorov S A , Ragimkhanov G B , Khalikova Z R 
Published: December 2020

Abstract
The Monte Carlo method calculated and tabulated the diffusion-drift characteristics of mercury ions in three inert gases (He, Ar, Xe) depending on the reduced electric field strength - the average energy of the ions, their longitudinal and transverse temperatures, diffusion coefficients along and across the direction of the field. The velocity distribution function of the ions and the angular dependence of the ions bombarding the surface are investigated
Further development of the Xe laser plasma 11-nm radiation source – new data on laser energy absorption and spectroscopy
Authors: Butorin P S , Kalmykov S G , Maximov V A , Sasin M E 
Published: December 2020

Abstract
Absorption of the laser pulse energy in the plasma has been shown to change from 8.5% at irradiation of a gas-puff target with a beam narrow-focused onto a near-central area of the jet up to 65% at the wide defocused irradiation. An analysis of this phenomenon is based on a hypothesis that plasma density decays significantly during the 10ns laser pulse due to hydrodynamic expansion of the hot plasma. A similarity of the EUV (Extreme UltraViolet) intensity and the laser light absorption as functions of the laser beam diameter suggests a revision of the conventional idea of a strong EUV radiation self-absorption in a cold peripheral shell of the laser plasma whereas the high absorptivity of the laser radiation by the plasma looks like a major feature to gain high efficiency of an EUV source.
Measurements of the plasma parameters at the edge of the FT-2 tokamak and comparison with the gyro-kinetic model
Authors: Kaledina O A , Shatalin S V , Esipov L A , Kouprienko D V , Lashkul S I 
Published: December 2020

Abstract
Diagnostics of a plasma edge is an extremely important field of tokamak physics because this region determines the plasma-surface interaction. In the paper the plasma density, electron temperature and radial electric field at the plasma edge of the FT-2 tokamak are analyzed using the results of probe measurements. The measurements were performed in the experiments conducted with a plasma pinch being in a symmetrical vertical position and were compared with the results derived by the ELMFIRE code simulations to correct the model calculations. The experimental observations are shown to be in a reasonable agreement with the gyro-kinetic model predictions.