bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bound states in the continuum in dielectric waveguides of finite size
Authors: Kutuzova Aleksandra A , Rybin Mikhail V 
Published: December 2020

Abstract
We study bound states in the continuum related supercavity modes in finite lattices of silicon rods. Two low-frequency symmetry-protected modes are examined. We find that Q factor has almost cubic dependence on the rod number and 50 rods are enough for Q exceeds 104. We discuss possible applications of these supercavity modes based on their electromagnetic field pattern. The structure surrounded by liquid media keeps its functionality by substitution silicon rods with rods made of Ge-Sb-Te.
Structure and luminescence properties of SiO2 sol-gel glass doped with Eu3+
Authors: Kravets V A , Ivanova E V , Zamoryanskaya M V 
Published: December 2020

Abstract
In this work, SiO2 sol-gel glass doped with Eu3+ was investigated its structural and luminescence properties. It was shown that a area containing crystallites of cristobalite with a size of about 45 nm is formed on the glass surface. The Eu3+ spectrum in surface area was obtained. It was demonstrated that the main part of the sample is X-ray amorphous; however, the Eu3+ spectrum in it demonstrates the presence of short-range order.
The GaAs laser photoconverter (λ 809 nm) current flow mechanisms at the temperature range of 100-420 K
Authors: Mintairov M A , Evstropov V V , Mintairov S A , Nakhimovich M V , Shvarts M Z , Kalyuzhnyy N A 
Published: December 2020

Abstract
The temperature dependences of the diffusion and recombination saturation currents and the energy gap have been obtained for a GaAs photoelectric converters. Saturation currents by IV characteristic analysis, and the energy gap by electroluminescence peak position have been determined. It has been shown that the relationship between saturation currents and energy band gap is characterized by the only parameter Jz (current invariant). At the temperature range of 100 -420 K this parameter does not depend on the temperature.
Gain spectra of lasers based on transitional dimension active region
Authors: Kornyshov G O , Gordeev N Yu , Payusov A S , Serin A A , Shernyakov Yu M , Mintairov S A , Kalyuzhnyy N A , Maximov M V , Zhukov A E 
Published: December 2020

Abstract
We present an experimental study of the optical gain of edge-emitting lasers based on a new type of quantum-sized InGaAs active medium grown on GaAs substrates, which we refer to as quantum-well-dots (QWDs). It is shown that the single layer QWD active region provide at least 33 cm−1 optical gain at 1030 nm comparable to the values typical for InGaAs quantum wells (QWs), and the width of the gain spectra characteristic for InAs quantum dots (QDs). Thus, QWD active region combines the advantages of both QW and QD heterostructures and has a great potential for improving characteristics of various semiconductor devices.
Vertical cavity surface emitting laser of 1.55 μm spectral range, manufactured by molecular beam epitaxy and wafer fusion technique
Authors: Blokhin S A , Bobrov M A , Maleev N A , Blokhin A A , Vasyl’ev A P , Kuzmenkov A G , Troshkov S I , Ustinov V M , Rochas S S , Gladyshev A G , Novikov I I , Karachinsky L Ya , Voropaev K O , Ionov A S , Egorov A Yu 
Published: December 2020

Abstract
The heterostructure design for 1.55 μm range VCSELs is proposed and realized. The wafer fusion technique was used to form the final heterostructure. The growth of AlGaAs/GaAs distributed Bragg reflectors (DBRs) on GaAs substrate and the optical cavity with an active region on InP substrate as well as a tunnel junction (TJ) regrowth was performed by molecular beam epitaxy (MBE). A key feature of the proposed design is the use of n++-InGaAs/p++-InGaAs/p++-InAlGaAs TJ, which allows, due to the effective removal of oxide from the InGaAs surface, to use MBE for re-growth of the TJ surface relief. Despite of the presence in heterostructure a narrow-gap InGaAs layers, a noticeable increase in internal optical loss in lasers can be avoided due to the short-wavelength shift of the edge of interband light absorption in ++-InGaAs layers (Burshtein-Moss effect). Fabricated VCSELs demonstrate single-mode operation with a threshold current less than 2 mA and a slope efficiency of ~ 0.46 W/A, which are comparable with characteristics of VCSELs with n++/p++-InAlGaAs TJ with a similar level of mirror losses.
Photoelectric properties of MIS structures on high-resistivity p-type silicon with aluminium nitride tunnelling insulator
Authors: Bazlov N V , Danishevskii A M , Derbin A V , Drachnev I S , Kotina I M , Konkov O I , Kuzmichev A M , Lasakov M S , Trushin M V , Unzhakov E V 
Published: December 2020

Abstract
Photoelectric properties of MIS tunnel diodes produced on high-resistive p-type silicon wafers with thin aluminium nitride AlN insulator layer and Pd or Al metal gate electrodes were investigated. It was found that synthesized AlN films possess a fixed positive charge, which leads to the creation of near-surface inversion layer in silicon substrate. The ratio of the photocurrent to the dark current K = Iph / Idark (on / off ratio) was found to depend on the gate electrode material, illumination intensity and the applied reverse bias. For studied MIS structures K ratio varied from 10 4 to 10 5 and was two orders of magnitude higher than that for the control MS structure without the insulator layer. High on / off ratio of such MIS structures with AlN tunnelling insulator promotes their application as an effective photodetectors in optoelectronics.
An experimental demonstration of the effect of mechanical stresses on the laser generation of acoustic vibrations in various materials
Authors: Glazov A L , Muratikov K L 
Published: December 2020

Abstract
The process of generating an acoustic signal during laser heating of metals and dielectrics is analyzed in the framework of the theory of thermoelasticity. A comparison of the experimental optoacoustic signal and the theoretical distribution of mechanical stresses for plates with a hole of aluminum alloy and silicon nitride is performed. It was found that the standard theory of thermoelasticity can qualitatively describe the dependence of the optoacoustic signal on the stress near the hole in the silicon nitride plate, but is not enough to correctly describe the dependence of the signal on the stress near the hole in the metal plate. It is noted that in order to achieve agreement between the obtained experimental and theoretical results for metals, in addition to the thermal effect of laser radiation on the lattice, it is necessary to take into account the additional effect of the electron system.
Investigation of time and frequency characteristics of the electrocaloric response in ferroelectric materials
Authors: Anokhin A S , Es’kov A V , Pakhomov O V , Semenov A A , Lähderanta E , Tselev A , Kholkin A L 
Published: December 2020

Abstract
Recently, much attention has been paid to the development of new microminiature solid-state cooling devices and heat energy converters based on the electrocaloric effect. But researchers pay little attention to aspects of the electrocaloric effect associated with its time and frequency characteristics. These phenomena must be taken into account when developing highly efficient thermodynamic cycles for solid-state cooling devices. In this work, we conducted an experimental study of the dependence of the electrocaloric response of a ferroelectric sample on the period and duty cycle of the control signal was studied. It was demonstrated, that value of electrocaloric response in studied ceramics may vary by more then 15% depending on period and duty cycle of electric pulses.
On the electrical conductivity of YCrO3 porous ceramics
Authors: Malcev D D , Sinelshchikova O Yu , Popkov V I 
Published: December 2020

Abstract
In this work, nanocrystalline yttrium orthochromite (YCrO3) was synthesized via the solution combustion method using metal nitrates and glycine. The resulting powder was used for sintering YCrO3 porous ceramics. The SEM, EDX, PXRD and TMA were used to examine structural and morphological features of both the preceramic powder and the sintered ceramics. The electroconductivity of the obtained porous ceramics was investigated in the temperature range from 25 to 1200 °C. YCrO3 bulk conductivity was found to depend on the microstructure and the pore volume fraction: at temperatures below 400 °C the electrical conductivity was higher than the values for high-density ceramics, while for temperatures above 800 °C the electrical conductivity of the resulting material approaches the values of high-density ceramics (σdc
= 1.97·10−2 S/cm at 1000 °C).
Peculiarities of the development of ionization instability of various scales in the air gas discharge
Authors: Lapushkina T A 
Published: December 2020

Abstract
In this work, the air gas discharge of constant voltage, organized in an unlimited chamber without the side walls, is experimentally studied, which leads to a stratification of the discharge region due to the development of ionization instability. Depending on the conditions of the discharge (pressure or magnitude of the gas discharge current), the scale of the ionization striations changes, which leads to the layered structure of the plasma medium and the possibility of creating layers of different thicknesses, where not only the electronic temperature, but also the gas temperature are different. Various types of discharge were obtained in the work, from large-scale structured ones (3-5 striations per discharge length) to small-scale ones (20-25 striations per discharge length), and the conditions for their occurrence and development were investigated. The main diagnostic parameters are gas pressure, the magnitude of the gas discharge current, which is changed by a change in the load resistance, the size and frequency of the ionization waves, estimation of electronic and gas temperatures at different points of the discharge. Gas discharges of this kind can be used to structuring the air environment, gas mixing and supersonic flows control.
Numerical simulation of turbulent wake of a flat plate subjected to adverse pressure gradient
Authors: Guseva E K , Strelets M Kh 
Published: December 2020

Abstract
Results are presented of a numerical study of the flat plate wake evolving under adverse pressure gradient. They include both results of the computational experiments aimed at supporting high accuracy of the performed scale-resolving simulations of the flow and results of the simulations aimed at quantitative evaluating of the effect of the adverse pressure gradient on the mean flow and statistical characteristics of the wake.
An experimental study of the effect of a shock wave front on a permeable material
Authors: Masyukevich A V , Bulovich S V 
Published: December 2020

Abstract
The interaction of shock wave with granulated layer of spherical particles was experimentally investigated in the atmospheric shock tube. There was a gap between porous layer and the end wall of tube. Two different cases were considered. In the first the structure and position of porous layer remained unchanged. In the second case, after the impact of the incident shock wave on the granular layer, the structure was destroyed and it turned into a moving particle cloud. For both cases, wave structures that occur both in front of porous layer of granular particles and in the gap between the layer and the end wall of the shock tube are obtained and analyzed.
Investigation of wood ash melting by AC plasma torch
Authors: Subbotin D I , Kirillova A A , Godina E P 
Published: December 2020

Abstract
One of the methods for processing ash from waste incineration can be plasma treatment. In most cases, studies are carried out with inert gas systems. The size of the processed pieces of sintered ash is 10-50 mm. The power of the plasma torch is 75 kW at an air flow rate of 8.8 g/s. Temperature control on the ash surface is carried out using a two-beam pyrometer. The total melting time is 7 hours. The temperature of the least heated part of the melt is 1300°C. Liquid slag is cooled in a large number of cold water. Upon contact of the hot molten slag with water, glass-like pieces 2-3 mm in size are formed. The composition and properties of the slag are studied using a scanning electron microscope with an attachment for elemental analysis and an X-ray diffractometer.
Numerical simulation of gravity-driven mono- and polydisperse bubbly flows in a three-dimensional column in the framework of the Euler-Euler approach
Authors: Chernyshev A S , Schmidt A A 
Published: December 2020

Abstract
The paper presents a comparison of the results of numerical modeling of the three-dimensional flow of mono- and polydisperse media in a rectangular bubble column reactor. The mathematical model used in the paper is based on the Euler – Euler description of a multiphase medium taking into account interphase momentum transfer, turbulence modeling of the carrier phase with bubble induced turbulence and polydispersity in the framework of the inhomogeneous multiple-size group (MUSIG) model. The comparison is carried out of the mono- and polydisperse approaches under the conditions studied for simplified and full formulations. Numerical results are compared with the available experimental data and simulations of other authors.
Compounding and technological methods for increasing the efficiency of wood matrix mineralization
Authors: Kilyusheva N V , Danilov V E , Ayzenshtadt A M , Belyaev A O 
Published: December 2020

Abstract
This paper presents the results of a study of the efficiency of mineralization of the plant matrix of pine wood samples by immersion of experimental samples in an organo-mineral water suspension (dispersion medium) and holding for 24 hours under natural conditions, as well as under autoclave impregnation at an excess pressure of up to 1.5 MPa. To create the necessary working pressure in the autoclave, an inert gas (argon) was used. As working fluids, we used an aqueous solution of arabinogalactan, aqueous suspension containing polymineral sand, pre-dispersed to a fine state and a soluble complex obtained by mechanical mixing of the above components. Prototypes were made from ordinary pine wood. The effectiveness of impregnation was evaluated by increasing the density of samples. In addition, data on changes in Brinell hardness, compressive strength of samples along the fibers, and water absorption of impregnated wood were obtained. It was found that autoclaving in the studied mode leads to an increase in the density of samples by more than two times, reduces their water absorption, and increases strength by 84%.
Formation of clathrate structures in surface layers of heavily diluted aqueous solutions
Authors: Shostka V I , Shostka N V , Halilov S I , Vershitsky V I 
Published: December 2020

AbstractThe paper presents the results of experimental studies related to the formation of clathrate structures in highly diluted hydrophilic aqueous solutions. A method based on the interference of laser beams transmitted through a water lens of various configurations is applied. It shown that the studied solutions have properties associated with the self-organization of the structure in clathrate states due to the cooperative effect of changes in the inhomogeneous network of hydrogen bonds. It is found that in the range of small concentrations of dissolved substances in aqueous solutions, in spite of some stabilization of the structures in the formed clathrates depending on the number of interacting molecules, the formation of associates of various shapes is possible. An increase in the content of dissolved substances in aqueous solutions leads to the destruction of the ordered structure, and the excess molecules of the hydrophilic substance, combined together, form complex aggregates or their “islands”.
Electron-stimulated desorption of potassium atoms from a potassium layer adsorbed on a tungsten covered with a gold film
Authors: Gromov I A , Kuleshova T A , Kuznetsov Yu A , Lapushkin M N , Samsonova N S 
Published: December 2020

Abstract
For the first time, electron-stimulated desorption (ESD) of K atoms from the K layer adsorbed on W covered with an Au film was detected and recorded, and the ESD yield was measured by a direct method depending on the electron energy, concentration K, and the thickness of the Au film. A model is proposed that explains the processes of ESD of potassium atoms from the surface.
Technology of nanoplanar surface preparation of GaSb and InP substrates
Authors: Zhirnov A M , Marichev A E , Epoletov V S , Prasolov N D , Levin R V , Pushnyi B V 
Published: December 2020

Abstract
In this work, we studied the surface quality dependence of GaSb and InP substrates prepared by various methods of pre-epitaxial preparation, specifically, etching, annealing, and growing a buffer layer. Our main goal was to obtain the most efficient method of pre-epitaxial treatment, which allows preparing substrates with the best surface quality. The experimental results were evaluated by the parameter of the average roughness of the substrate. As a result a combination of the methods of pre-epithelial preparation of GaSb and InP substrates was selected, which made it possible to obtain a root-mean-square surface roughness about 0.6–0.8nm.
Paramagnetism on the temperature-magnetization dependences in a superconducting semiconductor solid solution (PbzSn1-z)1-xInxTe
Authors: Denisov D V , Mikhailin N Yu , Shamshur D V , Parfeniev R V 
Published: December 2020

Abstract
In this work we studied magnetic properties of the semiconductor solid solution (PbzSn1-z)1-xInxTe in superconducting state. Peak-effect in magnetization vs magnetic field dependences was observed, and a paramagnetic response was obtained in superconducting state at certain magnetic fields and temperatures in a range of compounds. Possible relation between those effects is considered.
Supramolecular textures formed on polymer coating surface of solids: a mean-field study
Authors: Maksimova O G , Smirnov V V , Osipov S V , Menshikov E V , Egorov V I , Maksimov A V 
Published: December 2020

Abstract
We developed a mean-field model describing a system of interacting polymer chains in the contact with a spherical granule surface. It is shown that the size of supramolecular structures formed by macromolecules near the granules does not depend on the size of these granules but depends on the temperature and properties of polymer chains. We revealed that the size dependence of supramolecular formations on the mean molecular field changes sharply at the certain critical field value which depends on the temperature.
The change of the Earth Pole oscillational mode under the Lunar-Solar perturbations
Authors: Yu Barkin M , Bondarenko V V , Perepelkin V V 
Published: December 2020

Abstract
This article investigates conversion between different modes of the Earth Pole oscillational process which influence the precision of the Pole position forecast. It identifies the perturbing harmonic that leads to the saltatory change of the average velocity of Earth Pole motion and to the change of its oscillational mode. It also shows the qualitative conformity between the four-frequency model of the Pole motion and observation data based on the graph of phase variation of the polar angle of the Pole rotation around the average position.
An analytical calculation and applications of the kinematic characteristics of the motor vehicle movement at an oblique hitting the side of a cable barrier
Authors: Kolesnikova G P 
Published: December 2020

Abstract
An analytical calculation of the kinematic characteristics of a motor vehicle allows both checking the correctness of the developed FE model of cable barriers and can be used to study the movement of a motor vehicle directly during the construction of the FE model. In the article it has been provided recommendations on the procedure for conducting a virtual test in order to verify the correctness of the construction of the finite element (FE) model of the cable barriers, and also it has been analyzed the possibility of using analytical trajectories in the study of passive safety of the driver/passenger. FE modeling has been performed using the LS-Dyna multipurpose finite element complex. The present work continued researches which has been published as [1] and [2].
Three-parameter Model for Predicting the Earth pole Trajectory
Authors: Yu Barkin M , Perepelkin V V , Pochukaev V N , Filippova A S 
Published: December 2020

Abstract
A three-parameter model for forecasting the Earth pole motion is considered - a model with the minimum possible number of independent parameters and a satisfactory forecasting accuracy. The results of numerical simulation of the Earth pole oscillatory motion are compared with the observational data from the International Earth Rotation and Reference Systems Service. An analysis of the model accuracy is given.
Analysis of the effect of the physicomechanical properties of composite materials of carrier layers on the stress state of sandwich shells with rectangular cutouts
Authors: Bakulin V N 
Published: December 2020

Abstract
A model is described for studying the effect of the physicomechanical characteristics of composite carrier layers on the stress and strain state of sandwich cylindrical shells weakened by rectangular cutouts. The finite element model considered allows us to perform the layer-by-layer analysis of the stress in a wide range of physicomechanical characteristics of the layers. To obtain effective approximations leading to a high convergence rate of numerical solutions and to build the finite element of the carrier layers, the equations of the general sell theory are used. To build the finite element model of the filler, the elasticity theory equations for a three-dimensional body and the carrier layer finite element approximations obtained are applied. The effect of the physicomechanical characteristics of composite carrier layers on the stress and strain state for sandwich cylindrical shells with rectangular cutouts is studied.
Generalized multiparametric models for predicting the physical and mechanical properties of composites when exposed to extreme environmental factors
Authors: Gusev E L , Bakulin V N 
Published: December 2020

Abstract
Based on the formulated principle of model multiplicity forecasting and the introduced concept of optimal forecasting models difficulties in the framework of variational statements the questions of development are investigated effective refined forecasting methods that determine the physical-mechanical characteristics of structures made of composite materials. A system of additional ratios has been developed, including them in the structure of the initial tasks allowed us to significantly reduce the dimension the original variational statements of the inverse problems of forecasting and significantly narrow down the original set of valid model options predictions.
PAPR Performance of Carrier Interferometry OFDM by Wavelet Transform in Cooperative Relay Networks
Authors: Ciflikli Cebrail , Yazlik Bilgin 
Published: December 2020

Abstract
Cooperative diversity has spatial diversity effects on wireless communication systems to combat fading effects by using idle antennas as relays which are already located in the system. OFDM based cooperative communication is widely used in wireless communication systems and promises high data rate. However, OFDM has high PAPR problem. The high PAPR causes the interference and performance loss. Carrier interferometry codes boost overall performance of OFDM communication systems and decrease the level of PAPR. FFT can be used to realize carrier interferometry with no performance degradation. In this paper PAPR performance of the carrier interferometry OFDM by wavelet transform is analysed in a cooperative relay network. The results show that, the system which is a novel design of CI-OFDM has obviously better performance than traditional systems in terms of both BER and PAPR with the assist of wavelet transform.