bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical simulations of power characteristics and emission spectra of InAs(Sb)-based mid-infrared LED structures
Authors: Lipnitskaya S N , Semakova A A , Bazhenov N L , Mynbaev K D 
Published: December 2020

Abstract
Numerical simulations of power characteristics and emission spectra of LED structures with the active layer made of InAsSb with InSb molar fraction 0, 0.06 and 0.15 were performed. A satisfactory agreement between the modelled and experimentally recorded electroluminescence spectra was achieved for all the structures studied. The results of the modelling of the power characteristics showed very good design of the heterostructures in respect to carrier concentrations in their layers. Still, the results of the simulations predict that in theory the power of the studied LEDs can be enhanced by almost an order of magnitude.
Room temperature mid-IR two-color photodiodes with InAs and InAs0.9Sb0.1 absorbing layers
Authors: Klimov A A , Kunkov R E , Lukhmyrina T S , Matveev B A , Lebedeva N M , Remennyi M A 
Published: December 2020

Abstract
Narrow gap heterostructures consisting of two double heterostructures (N-InAsSbP/n-InAs/P-InAsSbP and P-InAsSbP/n-InAs0.9Sb0.1/N-InAsSbP) grown sequentially onto a n+-InAs substrate and further processed into a two-color photodiode with individual sensing operation at 3.3 and 4 have been studied. Presented and discussed are the photodiode construction details, I-V characteristics as well as sensitivity and detectivity spectra measured at room temperature.
Kinetic laws of the thermovoltaic effect in semiconductor structures based on samarium sulfide
Authors: Grevtsev M A , Kazakov S A , Havrov G D , Kazanin M M , Sharenkova N V , Solov’ev S M , Shulman S G 
Published: December 2020

Abstract
The experimental data on the thermovoltaic effect in bulk samples of samarium sulfide (SmS) are considered in this work in accordance with the represented kinetic model. The kinetic laws of the elementary process of samarium ions ionization have been studied, expressions are obtained for both the dynamics of the ionization process and the process statics in the context of the law of mass action in bulk samples of samarium sulfide. Such a description of the thermovoltaic effect made it possible to obtain the current-voltage characteristics of the samples at a constant temperature. All basic parameters were obtained for the thermovoltaic generator being developed: short circuit current and open circuit voltage; the internal resistance of the generator as well as the maximum power dissipation at the found load resistance was determined by calculation.
Thermal processes in SmS/Sm1-xGdxS heterostructures at the thermovoltaic effect
Authors: Solov’ev S M , Sharenkova N V , Kazanin M M , Kamenskaya G A 
Published: December 2020

Abstract
Thermal processes in SmS/Sm1-xGdxS heterostructures are investigated. It is noted that cooling is observed on the Sm1-xGdxS side when these heterostructures are heated. Cooling value is less than that of previously observed in SmS, but the stability is higher. It is shown that the main factor influencing the cooling effect is the collective casting of electrons into the conduction band from impurity levels. There are two multidirectional electron flows as a result of this fact - due to the thermovoltaic effect and due to the Seebeck effect.
Formation of SiO2 hard mask using dry etching and nanosphere lithography
Authors: Vyacheslavova E A , Morozov I A , Kudryashov D A , Gudovskikh A S 
Published: December 2020

Abstract
The features of the formation of a SiO2 hard mask using dry etching and nanosphere lithography are considered in the paper. A series of experiments was carried out using a variation of plasma etching parameters such as ICP and RF power, pressure as well as a substrate temperature. As a result, optimal parameters were found to obtain both good selectivity and high etching rate.
Photovoltaic converters with quantum objects under laser flux of subband photons
Authors: Panchak A N , Mintairov S A , Mintairov M A , Salii R A , Kalyuzhnyy N A , Nakhimovich M V , Shvarts M Z 
Published: December 2020

Abstract
Quantum objects in the host material of photovoltaic converters can expand the spectral sensitivity to the long-wavelength spectral region. Samples with InAs quantum dots and thin layers in the host GaAs material were studied theoretically with the assumption of high-power laser subband irradiation input. Threshold factors have been established that affect the possibility of radiation heating. For noticeable increase in the temperature of the base material the necessary illumination values were estimated.
Efficiency enhancement in planar perovskite solar cells under low-light illumination and ambient lighting
Authors: Kozlov S S , Alexeeva O V , Nikolskaia A B , Vildanova M F , Shevaleevskiy O I 
Published: December 2020

Abstract
Hybrid organic-inorganic perovskite solar cells (PSCs) have attracted significant interest owing to their high power conversion efficiency (PCE) and low cost. Moreover, PSCs demonstrate high performance under low light illumination without significant reduction in PCE. However, photovoltaic properties of PSCs under low light conditions are rarely reported. Here, the potential of planar PSCs for efficient performance under low illuminance conditions was investigated. Planar perovskite solar cells with FTO/c-TiO2/c-SnO2/CH3NH3PbI3/Spiro-MeOTAD/Au architecture were studied under variable illumination intensities in the range of 10 – 1000 W/m2. Significant enhancement in PCE up to 18.4% was observed for planar PSCs under low light conditions (<100 W/m2), as compared to the 16% PCE value obtained under AM1.5 illumination. This was attributed to the decreased charge accumulation at the ETL/perovskite interface and increased charge collection efficiency under low light illumination. PSCs performance was additionally studied under artificial LED lighting (5500K, 1000 lux) and the PCE values exceeding 24% were obtained. The results of this work verify excellent low-light performance of planar PSCs and provide the possibility for their application as power sources for various low-power wireless devices (sensors, detectors, Internet of Things devices, etc.).
Connecting the numerical and analytical ionization times for quantum dots in semiconductor wires driven by alternating field
Authors: Khomitsky D V 
Published: December 2020

Abstract
Recent numerical results for ionization of quantum dots by periodic electric field during the electric dipole spin resonance are compared with known analytical approaches. It is found that in finite-length quantum wires the numerical ionization rate is slower than the analytical one, especially for low driving field when the confinement potential strongly affects the dynamics. Still, the analytically predicted ionization times are in satisfactory correspondence with mean energy threshold times when the energy crosses the border between localized and continuum states.
Transonic flow bifurcations over a double wedge
Authors: Kuzmin A. 
Published: December 2020

Abstract
Inviscid and turbulent airflows over a symmetric flat-sided double wedge are studied numerically. Solutions of the Euler and Navier-Stokes equations are obtained with a finite-volume solver on fine meshes. The solutions demonstrate both symmetric and asymmetric flow regimes in significant bands of the free-stream Mach number at zero angle of attack. The realization of a certain regime depends on the time history of boundary conditions. A physical interpretation of transitions between the symmetric and asymmetric flows is suggested.
On plasma neutralization of the ion beam
Authors: Shalenov E O , Dzhumagulova K N , Ramazanov T S , Tikhonov A , Kaikanov M 
Published: December 2020

Abstract
Simulation of the thermal motion of ions in a spherical bunch was performed on the basis of the molecular dynamics. The Yukawa potential was used to describe the ion interactions. Obtained data showed good agreement with results of theoretical investigation. The conclusion was done that INURA accelerator needs good plasma neutralization in order to keep transverse size of the ion beam.
Influence of increased magnetic field on Alfvén eigenmodes on upgraded spherical tokamak Globus-M2
Authors: Balachenkov I M , Petrov Yu V , Gusev V K , Bakharev N N , Bulanin V V , Varfolomeev V I , Dyachenko V V , Zhiltsov N S , Kiselev E O , Konovalov A N , Krikunov S V , Kurskiev G S , Minaev V B , Patrov M I , Petrov A V , Ponomarenko A M , Sakharov N V , Telnova A Yu , Shchegolev P B , Yashin A Yu 
Published: December 2020

Abstract
During modernization of the Globus-M tokamak, toroidal magnetic field and plasma current were increased, and a number of diagnostics were upgraded, which made it possible to study phenomena associated with the excitation of Alfvén waves in a spherical tokamak in a wider range of plasma parameters. In the experiments with neutral beam injection, the dependences of fast particle losses initiated by the toroidal Alfvén eigenmodes (TAE) on their magnitude in the magnetic field range of 0.4 – 0.7 T and currents of 180 – 330 kA were acquired. Resulting dependences confirm previously obtained results and indicate a decrease in losses with increasing magnetic field and plasma current. At the same time, a number of new phenomena, that have never been observed on Globus-M were detected. In experiments with neutral beam injection at the current ramp up stage, Alfvén cascades (AC) in the frequency range of 100 – 300 kHz were observed for the first time. By means of the Doppler backscattering diagnostics (DBS), it was shown that ACs are localized closer to magnetic axis unlike TAE. Also, during low hybrid wave current drive (LHCD) experiments, global Alfvén eigenmodes (GAE) were detected at a frequency close to 1 MHz, apparently driven in the resonance with runaway electron beam. Detected global eigenmodes are also able to arise in ohmic discharges, however, their magnitude is lower.
Three-dimensional visualization of flow pattern near transport airplane model with operating propellers in wind tunnel
Authors: Chernousov VI , Krutov A A , Pigusov E A 
Published: December 2020

Abstract
This paper presents the experiment results of three-dimensional visualization of flow pattern behind the wing and fuselage of the light transport aircraft (LTA) model with operating propellers in the T-102 TsAGI subsonic wind tunnel (WT). Studying the flow pattern, it is possible to recognize the features of the flow and aerodynamic interference of model elements. As a result of the analysis of the flow pattern and comparison with the previously obtained integral characteristics, the model elements for improving the aerodynamic perfection of the aircraft are revealed. It is shown that at operational angles of attack behind the main landing gear fairing, the vortex flow forms, increasing drag and, apparently, negatively affecting the longitudinal stability characteristics. Vortices are formed behind the flattened tail of the fuselage. Thus, the visualization of the flow with dacron ribbons is an effective method of obtaining flow pattern around the airplane model elements in WT.
Oscillatory solutions for a diode with counter-streaming electron and ion beams
Authors: Kuznetsov V I , Flegontova E Yu , Bakaleinikov L A 
Published: December 2020

Abstract
A plasma diode with counter-streaming electron and ion beams has as a rule more than one time-independent solution. Stability features of the steady state solution with ion reflection from a potential barrier are studied numerically. It was found that there is a threshold in the diode length beyond which nonlinear oscillations occur as an alternative instead of such solutions. Features of the oscillations are studied.
Heat flux measurement at the initial phase of normal shock wave reflection using the sensor on anisotropic thermoelements
Authors: Popov P A , Sakharov V A , Poniaev S A , Monakhov N A , Kotov M A 
Published: December 2020

Abstract
Thermal measurements were carried out using the sensors on anisotropic thermoelements during normal shock wave reflection with Mach number M = 3 … 5. The method of processing of sensor’s electric signal has been tested at low signal / noise ratio and characteristic time ∼0.1 μs.
Monte Carlo simulation of electron drift characteristics in an inert gas with mercury vapor
Authors: Kurbanismailov V S , Maiorov S A , Ragimkhanov G B , Khalikova Z R 
Published: December 2020

Abstract
The Monte Carlo method calculated the kinetic characteristics of electron drift in three inert gases (He, Ar, Xe) in the presence of small impurities (up to 1%) of mercury vapor at an electric field strength E/N = 1-2000 Td taking into account inelastic collisions and analyzed the effect of the concentration of metal vapor on the drift velocity, average electron energy, diffusion and mobility coefficients. In addition, the Townsend ionization coefficient and electron runaway, the electron energy distribution function, and their comparison with the Maxwell and Druvestein distributions are calculated. It has been shown that even insignificant additions of mercury atoms to an inert gas, starting with a fraction of a percent, strongly affect the discharge, in particular, the characteristics of inelastic processes and the charge composition.
Control of tokamak discharge parameters using a plasma jet
Authors: Goryainov V Yu , Voronin A V , Gusev V K , Minaev V B , Novokhatsky A N , Petrov Yu V , Sakharov N V 
Published: December 2020

Abstract
Results of the experimental study of the ability of plasma jet of coaxial accelerator to breakdown and ionization the working gas at the initial discharge phase in Globus-M2 spherical tokamak are presented. Studies of the development of the initial stage of discharge initiated with a plasma jet showed that the plasma current in the discharge began to grow earlier by 2 ms than using the standard inductive breakdown. The breakdown voltage decreased from 6.1 to 3.1 V (-49%) at 4.7 kV accelerator electrode voltage. The emission intensity of line Dα decreased during formation of the discharge with the help of plasma jet without additional gas puffing. Radiation level CIII in the discharge generated by the plasma jet was the same as the radiation in discharge produced by induction breakdown of the gas. At the stage of increase in the plasma current the most intense visible radiation of the plasma was found near duct through which the jet was injected. Discharge radiation decreased and spread out along the cross section of the plasma column during plasma current plateau.
Investigation of gasdynamic parameters of a supersonic flow near a body at various Mach numbers
Authors: Shevchenko A V , Yuriev A S , Poniaev S A , Zhitnikov T A , Panfilov E B , Rotermel A R 
Published: December 2020

Abstract
Interaction of a body with an incident supersonic flow is considered. By using numerical and experimental methods, gas-dynamic parameters of the supersonic flow near the body are determined for various Mach numbers. Theoretical calculations of the supersonic flow around a body are carried. The mathematical models used in the calculations are verified by the results of experimental studies performed in the IT-1M hypersonic impulse tube of the aerodynamic laboratory of the Mozhaysky Military Space Academy.
Investigation of the interaction of conical bodies with an supersonic flow at low angles of attack
Authors: Shevchenko A V , Yashkov S A , Zhitnikov T A , Rotermel A R , Poniaev S A , Prokopenko E A 
Published: December 2020

Abstract
The study of the interaction of conical bodies with an incident supersonic flow is carried out. In the presented theoretical and experimental studies, the parameters of the incident flow near the investigated bodies were determined at different Mach numbers. Experimental studies were carried out using a supersonic atmospheric-vacuum tube of the aerodynamic laboratory of the Mozhaysky Military Space Academy. The theoretical study is based on the model of a viscous perfect gas described by the Navier-Stokes equations.
Drastic change in surface electronic properties and creation of a new carbon-based nanostructure on the vicinal SiC(111)-4° surface
Authors: Timoshnev S N , Benemanskaya G V , Kukushkin S A 
Published: December 2020

Abstract
Novel carbon based nanostructure on the vicinal SiC(111)-4° surface has been found as effect of Cs adsorption. The SiC(111)-4°sample was grown by method of epitaxy of low-defect unstressed nanoscaled silicon carbide films on vicinal Si(111)-4° substrate. Electronic structure of the SiC(111)-4° surface and the Cs/SiC(111)-4°interface has been detailed studied in situ in an ultrahigh vacuum using synchrotron-based photoelectron spectroscopy. The C 1s and Si 2p core level spectra have been investigated as a function of Cs submonolayer coverage. A unique fine structure of the C 1s core level spectrum was revealed to appear under Cs atomic layer deposition. The effect was ascertained and shown to be originated from the interaction of the silicon vacancy with adsorbed Cs atoms that leads to both the redistribution of electron density and surface reconstruction with formation of a new type of the C-enriched aromatic-like nanostructure.
Laboratory sources of gravitational waves
Authors: Fomin I V , Gladyshev V O , Gorelik V S , Kauts V L , Kaytenko A V , Sharandin E A 
Published: December 2020

Abstract
We consider the possibility of generating and subsequently detecting artificial gravitational waves in a laboratory based on different approaches. As one of the methods for creating gravitational waves, we investigate oscillations of the ions of the crystal lattice of a dielectric under the influence of high-power laser radiation. The characteristics of gravitational waves obtained by this method are compared with the results of using the other approaches as well.
The influence of the Earth’s oblateness on the image motion velocity during the electro-optical survey of the planet’s surface
Authors: Nikulkina I M , Osipova L S , Shatina A V 
Published: December 2020

Abstract
In this paper we derive the formulas describing velocity of the planet’s surface orbital survey image in the focal plane, obtained via on-board electro-optical equipment in the nadir-viewing geometry, with consideration for the Earth’s oblateness. The Earth is modeled as a perfectly rigid spheroid uniformly rotating about its axis of symmetry. The orbit of the satellite’s mass center is perturbed because of the Earth’s oblateness in the direction of its rotation axis. The orbital camera’s prime focus is located in the satellite’s mass center. We present the graphs of image motion velocity vector coordinates in the focal plane depending on time (true anomaly) and the graphs of the velocity fields. The obtained results are compared to the results in case of a spherical Earth. In the latter case the satellite’s mass center moves along a Keplerian elliptic orbit. Key words: image motion velocity, focal plane, Earth’s satellite.
Possible solutions of inverse dynamical problems with regards for nonlinear constraint stabilization function
Authors: Kaspirovich I E , Mukharlyamov R G 
Published: December 2020

Abstract
Baumgarte’s method of constraint stabilization can be applied to find a stable numerical solution in relation for constraint equations during the numerical integration. According to this method full time derivatives of constraints are equated to their arbitrary linear form. Choosing values of the coefficients of this form allow us to obtain a stable solution. In this paper a method of constructing Lagrange equations of the second kind is considered with regard for a nonlinear homogeneous stabilization function. A necessity if introducing dissipative function to find a complete stabilization problem’s solution can be the main conclusion of the research.
Determination of critical Reynolds number in the jet based on the theory of stochastic equations and equivalence of measures
Authors: Dmitrenko A V 
Published: December 2020

Abstract
On the basis of the theory of stochastic equations and the theory of equivalence of measures, the flow in a plane jet is considered. As a result, in accordance with these theories, the analytical dependence for the critical Reynolds number and the expression for the critical point of the transition from the laminar flow to turbulent motion in the jet are derived. The calculations carried out using new formulas showed satisfactory agreement with the known experimental values of the critical Reynolds number.
The Spectrum of the turbulence based on theory of stochastic equations and equivalenceof measures
Authors: Dmitrenko A V 
Published: December 2020

Abstract
The formation of the spectrum of turbulence in the inertial interval on the basis of the new theory of stochastic hydrodynamics is presented. This theory is based on the theory of stochastic equations of continuum laws and equivalence of measures between random and deterministic movements. The purpose of the article is to present a solution based on these stochastic equations for the formation of the turbulence spectrum in the inertial interval in the form of the spectral function E(k)j depending on wave numbers k in form E(k)j∼kn. The results of analytical solutions showed a satisfactory correspondence of the obtained dependence with the classical Kolmogorov’s dependence in the form of E(k)j∼k5/3.
Estimation of the probable size of the lunar core based on geophysical and geochemical data
Authors: Kronrod E , Kuskov O , Matsumoto K , Kronrod V 
Published: December 2020

Abstract
This study is devoted to estimations of the possible sizes of the lunar core, which were obtained with two independent approaches based on solving the inverse problem of determining the internal structure and composition of the Moon. For calculations Monte Carlo method was used taking into account geophysical and geochemical constraints on the models. In the first method, the inverse problem was solved for two different temperature models (“cold” and “hot”). In the second method, two different models of the bulk composition of the lunar mantle (Earthlike and enriched in Al2O3) were considered. Both approaches led to similar values for the radius of the lunar core. It was found that the radii of Fe-S core are in the range of 50-350 km with the most probable value of about 300 km (∼ 1% of the mass of the Moon) and are rather weakly dependent on the thermal regime and chemical composition of the lunar mantle.
Experimental solution of Buquoy’s problem
Authors: Domnyshev A A , Kalinichenko V A , Shkapov P M 
Published: December 2020

Abstract
This article addresses the problem in which a chain moves vertically upward from a horizontal plane under constant force – Buquoy’s problem. For the first time, an original technique is proposed for the experimental solution of this problem. The chain’s motion is studied in liquid (water), and the buoyancy force of the float attached to the chain serves as a constant force. The experiment reveals converging oscillation of the system at various displacements of the chain relative to the equilibrium position. The differential equation of chain motion which describes this variable mass system is solved by the numerical technique. A comparison of theoretical and experimental data is made.
Face Recognition and Temperature Data Acquisition for COVID-19 Patients in Honduras
Authors: Sorto A , Marquez T , Carrasco A , Ordoñez J 
Published: December 2020

Abstract
Honduras health workers are reduced; doctors and nurses are getting infected by COVID-19. The primary purpose of this project is the design and development of software that performs facial recognition and temperature registration for patients. The incremental model was used to develop the software. The algorithm was trained with 5 images per face for the first test and 10 images per face for the second, with a total sample of 80 participants. At a maximum distance of 1.4 meters from the camera, the system obtained 72% and 82% accuracy for each of the tests. Finally, the authors conclude that the system can be implemented in health areas such as laboratories, hospitals, and clinics so that contact between patients and doctors can be reduced.