bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of the photon detection efficiency of silicon photomultipliers for the new detector cluster of the Cherenkov gamma-ray telescope TAIGA-IACT equipped with UV filters
Authors: Kuleshov D O , Simonyan V A , Bogdanov A A , Kholupenko E E , Tuboltsev Yu V , Chichagov Yu V , Krassilchtchikov A M 
Published: December 2021

Abstract
This study was devoted to measurements of the UV-range photon detection efficiency (PDE) of OnSemi MicroFJ SiPM detectors use together with custom UV filters and of the transmission coefficient of these filters at 277 nm. The final goal of these measurements was to determine feasibility of the filters for the new detector cluster of the TAIGA-IACT telescope. PicoQuant PLS-270 UV source emitting pulses at 277 nm was calibrated. The obtained dependences of the registered radiation power on the distance between the emission source and the reference detector are well approximated by the inverse square function, hence no significant scattering or absorption influenced the PDE measurements. The dependences of the number of detected photons on the distance between the source and the detector were obtained. These dependencies are also well approximated by the inverse square function. The PDE of SiPM MicroFJ-60035 detector was measured at the level of 10.0 ± 0.7%. The transmission coefficients of the considered set of filters at the wavelength of 277 nm were also obtained. The SL 240-300 filter has a sufficiently high transmission coefficient and it is advisable to use it as a bandpass ultraviolet filter in the new detector cluster of the TAIGA-IACT telescope; the SL 290-590 filter absorbs ultraviolet light quite well and is applicable in the visible range.
The effect of gamma quanta absorption due to interaction with thermal bremsstrahlung photons of hot gas in galaxy clusters
Authors: Popov A N , Barsukov D P , Ivanchik A V , Bobashev S V 
Published: December 2021

Abstract
The interaction of gamma quantum from distant sources with thermal bremsstrahlung photons of hot intracluster gas with producing electron-positron pair in case of 10 galaxy clusters is considered. It is supposed that intracluster gas in considered clusters is isothermal and electron number density may be described by β distribution with β = 2/3. It is presented that the optical depth due to considered interaction is about 10−8 — 10−.
Dynamics of Langmuir waves due to induced scattering on thermal electrons of solar plasma
Authors: Kudryavtsev I V 
Published: December 2021

Abstract
The temporal evolution of Langmuir waves due to induced scattering on thermal electrons of solar plasma for a case of anisotropic distribution of waves is considered. The results of calculations are submitted. It is shown that the induced scattering of waves on thermal electrons does not lead to isotropization of Langmuir waves. But effective transition of energy from waves with the large wave vectors to waves with smaller wave vectors occurs similar to the isotropic case.
The impact of laser-induced thermocoagulation effects on the optical spectra of brain tissues
Authors: Israpov E Kh , Giraev K M , Ashurbekov N A , Rabadanov K M , Magomedov M A 
Published: December 2021

Abstract
In this work, the results of spectral and optical studies of the grey matter tissues of the brain by a laser hyperthermia action are presented. The coefficients of optical absorption and transport scattering in the spectral range of 250-1500 nm are determined, and the features of the spatial distribution of the laser radiation intensity in the studied objects are identified. It is shown that the coagulation effects lead to compaction and an increase in the concentration of endogenous chromophores and structural elements, which is reflected in the optical properties of biological objects.
Comparative analysis of the secondary structure of non-histone chromatin proteins HMGB1 and HMGB2
Authors: Chikhirzhina E V , Osinnikova D N , Polyanichko A M 
Published: December 2021

Abstract
The non-histone chromosomal proteins HMGB1 and HMGB2 were found in the cells of all studied eukaryotes. They are involved in cell decision and many biological processes such as replication, transcription, repair, etc. In this work, the secondary structure of the HMGB1 and HMGB2 proteins was studied by the circular dichroism method. It was shown that, despite the high homology between them, the secondary structure of these proteins is different. The revealed structural features, most likely, should influence their functions in the cell nucleus, in particular, the interaction with DNA and other proteins.
Performance characteristics of bistable active ring resonators based on ferrite films
Authors: Vitko V V , Haponchyk R V , Nikitin A A , Ustinov A B 
Published: December 2021

Abstract
A bistability phenomenon in a ring resonator consisting of a delay line on surface spin waves and a microwave amplifier has been experimentally investigated. It is shown that an enhancement of the gain coefficient above a specified value provides an appearance of a hysteresis at the resonator transmission characteristic. A frequency range of the bistability broadens due to an increase of the gain coefficient as well as the external magnetic field. While the value of the gain is limited from above by a transition of the ring into a self-oscillating regime, an increase in the magnetic field from 1150 Oe up to 3150 Oe provides an expansion of the frequency range of the hysteresis from 77 kHz to 185 kHz.
Local stress fields in solids estimated by acoustical emission method
Authors: Hilarov V L , Damaskinskaya E E 
Published: December 2021

Abstract
Based on the Zhurkov’s kinetic concept of solids’ fracture a local internal stress estimation method is introduced. Stress field is computed from the time series of acoustic emission intervals between successive signals. For the case of two structurally different materials the time evolution of these stresses is examined. It is shown that temporal changes of these stresses’ accumulation law may serve as a precursor of incoming macroscopic fracture.
Application of the liquid bridges theory to find the melt menisci shape when growing cylindrical crystals
Authors: Galaktionov E V , Bakholdin S I , Galaktionova N E , Tropp E A 
Published: December 2021

Abstract
A vertical liquid bridge of small volume between a conical shaper and a convex crystallization front was investigated. Two variants of the front crystallization shape selection are considered: a conical and a spherical fronts. A variational statement of the original problem is given. As the boundary conditions we used the condition of engagement at the edge of the shaper and a given growth angle at the crystallization front. The Bond number was assumed to be small, and to find a solution of the problem the asymptotic approach was applied. The calculations are carried out for small diameter cylindrical sapphire crystals, grown from the melt by the Stepanov method. The results of the menisci shapes calculations are presented. The comparison of the results of calculations for conical and spherical crystallization fronts is carried out.
Simulation of pulse wave propagation using one-dimensional models of hemodynamics
Authors: Krivovichev G V , Egorov N V 
Published: December 2021

Abstract
The models of hemodynamics, corresponding to the inviscid, Newtonian, and non-Newtonian models, are compared. The models are constructed by the averaging of the hydrodynamic system on the vessel cross-section. For the inviscid case, the analytical solution of the problem for pulse propagation is obtained. As the result of the comparison, the deviations of the solutions for non-Newtonian models from the Newtonian and inviscid cases are demonstrated.
Investigation of defects in structures based on BP/Si heterojunction
Authors: Maksimova A A , Baranov A I , Uvarov A V , Kudryashov D A , Gudovskikh A S 
Published: December 2021

Abstract
In this work the properties of the BP/Si heterojunction interface were investigated by capacitance methods, the deep levels transient spectroscopy method and admittance spectroscopy. Admittance spectroscopy did not detect any defects, but the deep level transient spectroscopy showed response with activation energy of 0.33 eV and capture cross-section σn=(1-10)·10-19 cm2 and defect concentration (NT) is in the order of 1013 cm-3. This defect level is a trap for electron with position of 0.33 eV below the conduction band in region near the BP/Si interface.
Raman studies of amorphous nanocarbon obtained by laser sputtering
Authors: Eliseyev I A , Smirnov A N , Davydov V Yu , Platonov A V , Yavsin D A , Gurevich S A 
Published: December 2021

AbstractThe structural properties of amorphous nanocarbon films fabricated by laser sputtering of a graphite target are investigated by means of Raman spectroscopy. Analysis of the spectral features in the region of 100–3600 cm-1allowed us to determine the allotrope composition of the films and the degree of disorder in terms of average crystallite size. The results obtained are important for application of such films in the field of electrode coatings.
Ultra-heat resistant nanocomposites based on heterocyclic networks: structure, properties, origin of thermal stability
Authors: Yakushev P N , Bershtein V A , Fainleib A M , Kirilenko D A , Melnychuk O G 
Published: December 2021

Abstract
A series of the hybrid Bisphenol A based Phthalonitrile (BAPhN)/amino-Montmorillonite (amino-MMT) polymer nanocomposites with the complex heterocyclic matrix network and 0.03–5.0 wt.% amino-MMT were synthesized and studied. Their molecular structure, nanostructure, molecular dynamics, thermal, relaxation and elastic properties were characterized using TEM, EDXS, DMA, TGA, FTIR and Far-IR spectroscopies including also the experiments in flowing nitrogen medium. Depending on nanofiller content, different extents of MMT stacks exfoliation, from a single nanolayer to stacks with tens nanolayers-thickness, were registered in these nanocomposites. The exceptional combining of high temperature properties was revealed for these nanocomposites.
Development of self-cleaning SERS-active nanostructures based on ZnO nanorods and Ag nanoparticles
Authors: Novikov D V , Malakhov N S , Tarasov A M , Savitskiy A I , Dubkov S V , Gromov D G , Eganova E M 
Published: December 2021

Abstract
This work demonstrates the possibility of using a combination of zinc oxide nanorods with silver nanoparticles as a self-cleaning SERS substrate. In addition to Raman scattering enhancement such structures demonstrate the self-cleaning effect during UV treatment. The ZnO nanorods (NRs) array was synthesized on a ZnO seed layer by the hydrothermal method. The Ag nanoparticles (NPs) array was formed by vacuum thermal evaporation over the ZnO NRs. Rhodamine-B 230 μM solution has been detected using the formed SERS-substrates without additional mathematical processing of the Raman spectra. Subsequent UV radiation treatment showed a 3-fold decrease in the intensity of the spectral peaks of the analyte.
Study of the electrophysical and gas-sensitive properties of thin ZnO-SnO2 films formed by the sol-gel method
Authors: Starnikova A P , Gulyaeva I A , Storozhenko V Yu , Volkova M G , Bayan E M , Petrov V V 
Published: December 2021

Abstract
Thin films of ZnO-SnO2, with a molar ratio of Zn: Sn = 0:100, 1:99, and 5:95, were synthesized by the sol-gel method. As a result of a study of the electrophysical and gas-sensitive properties of thin ZnO-SnO2 films, the effect of a decrease in the working temperature at low concentrations of zinc oxide was found. The value of the coefficient of gas sensitivity of ZnO-SnO2 films correlates with the activation energy of conduction. For sensor structures based on films with a composition of: 5:95 at a working temperature of 200 °C, a higher gas sensitivity coefficient and the fastest response among all the samples under study are observed.
Elliptic flow for φ-mesons in Cu+Au and U+U collisions
Authors: Mitrankov Iu M , Bannikov E V , Berdnikov A Ya , Berdnikov Ya A , Kotov D O 
Published: December 2021

Abstract
An important goal of current ultra-relativistic heavy ion research is the investigation of the quark-gluon plasma (QGP). Measurements of elliptic flow lend insight on reaction dynamics and are important for defining parameters of viscous hydrodynamic, which can describe QGP behavior. In this paper elliptic flow for φ-mesons in Cu+Au collisions at

s

N
N

=
200

GeV

and in U+U collisions at

s

N
N

=
193

GeV

GeV is studied as a function of kinetic properties and centrality. The obtained results are compared to hydrodynamic model predictions. New FVTX detector and combinations of different approaches of flow measurements provide a possibility to measure the elliptic flow for the φ-mesons for the first time as a function of centrality at PHENIX. The elliptic flow for φ-mesons in Cu+Au and U+U collisions as function of transverse kinetic energy per one quark follows the trend for other hadrons with respect to the number of quarks in hadrons, regardless of centrality. This result along with agreement of obtained data to hydrodynamic model iEBE-VISHNU predictions suggests that QGP can be described with viscous hydrodynamic with specific viscosity η/s = 1/(4π).
Influence of α-particles irradiation on the properties and performance of silicon semiconductor detectors
Authors: Bakhlanov S V , Bazlov N V , Chernobrovkin I D , Derbin A V , Drachnev I S , Kotina I M , Konkov O I , Kuzmichev A M , Mikulich M S , Muratova V N , Trushin M V , Unzhakov E V 
Published: December 2021

Abstract
Deterioration of the operation parameters of p-type Si surface-barrier detector and Si(Li) p-i-n detector upon irradiation by alpha-particles was investigated. The detectors were irradiated at room temperature up to a total number of the registered α-particles Nα
equal to 6 × 109. Prolonged irradiation has resulted in a deterioration of the detectors energy resolution ability and it was found that the increase of α-peaks broadening can be described by a linear function of Nα
with a slope Δσ/ΔNα
∼ (1.4–1.8) × 10–9 keV/α for both detectors. Resolution deterioration was associated with the increase of the detectors leakage current, which proceeds linearly with the number of absorbed α-particles with the slope ΔI/ΔNα ∼ (7-17) × 10-17 A/α. The increase of the detectors reverse current was related with appearance of radiation-induced defect level at 0.56 eV above the valence band.
Optical and structural studies of Hg0.7Cd0.3Te samples grown by various methods
Authors: Andryushchenko D A , Ruzhevich M S , Smirnov A M , Bazhenov N L , Mynbaev K D 
Published: December 2021

Abstract
Photoluminescence and X-ray diffraction (XRD) were used for the studies of the properties of HgCdTe samples with CdTe molar fraction x=0.3 grown by various methods. According to the results of photoluminescence studies, all samples possessed a considerable degree of alloy disorder, yet the scale of the disorder seemed not to be directly related to the structural quality of the material as revealed using XRD. Prospects of using HgCdTe material grown by various methods in optoelectronic devices are discussed.
Influence of attenuation on the generation of optical vortices in multihelicoidal optical fibers
Authors: Alexeyev C N , Alieva S S , Barshak E V , Lapin B P , Yavorsky M A 
Published: December 2021

Abstract
In this paper we have studied influence of attenuation on conversion processes of the fundamental mode (FM) in multihelicoidal optical fibers (MHF) in the vicinity of the point of accidental spectrum degeneracy within the framework of the scalar approximation. To this end, we have obtained expressions for modes of the MHF, which consist of the FM and an optical vortex (OV), and shown that conversion of the FM into the OV takes place. The difference in the attenuation coefficients for the partial fields of MHF’s modes leads to deterioration in the conversion process even with an ideal system’s tuning. At sufficiently large values of attenuation coefficients the conversion of the incoming FM into the vortex vanishes. Also we have shown the presence of exceptional point (EP) in the spectra of modes of the MHF and demonstrated enhanced sensitivity of the fiber in the vicinity of the EP to perturbations.
Influence of small additives of germanium on the physical properties of chalcogenide glasses based on composition As30.5S44.5I25
Authors: Klinkov V A 
Published: December 2021

AbstractAdvanced for the infrared region of the spectrum chalcogenide glass composition As30.5S44.5I25with small germanium additives were investigated. The concentration dependences of some physical and chemical properties indicate an increase in the performance of glasses due to the modification of the glass network. The character of the change in the short-wavelength absorption edge with an increase in the content of germanium atoms had an exponential character, shifting from 597 to 582 nm. A non-monotonic dependences were also found for the values of density, refractive index, and glass transition temperature. A joint analysis of the results obtained and structural studies described in the literature for similar glass systems made it possible to propose possible structural groups of glass compositions under investigation.
NEXAFS study of carbonate substituted bioapatite
Authors: Petrova O V , Bakina K A , Ehrlich H 
Published: December 2021

Abstract
The investigation of unique carbonate substituted bioapatite of Champsocephalus gunnari icefish jaw and skull bones was carried out using NEXAFS spectroscopy. It has been established that these bones contain the B-type carbonate substituted hydroxyapatit with a content [CO3]2- anion of about 0.79-3.07 wt.%.
The research of the composition of mineral component of compact bone tissue after flow delipidation using the optic method
Authors: Timchenko P E , Timchenko E V , Pisareva E V , Vlasov M Y , Frolov O O , Volova L T , Samigullin R T , Sergeeva S S 
Published: December 2021

Abstract
The results of the research of bone mineral component (BMC) composition using the Raman spectroscopy method are presented in the work. The subjects of the research were the groups of BMC samples made of compact bone tissue of cows using “Lyoplast”® technology where vacuum delipidation of initial material was replaced by the flow one by washing it out in hydrogen peroxide and ether. The solution filtration after bone tissue demineralization was used as additional treatment. The results of the experiment show that the flow delipidation can be used for preparing this biomaterial (BMC), which is cost-effective compared to standard vacuum cleaning and additional filtration stage can be rejected.
Fullerite C60 optical constants in the C 1s NEXAFS region
Authors: Sivkov D V , Nekipelov S V , Petrova O V , Bogachuk D V , Skandakov R N , Sivkov V N 
Published: December 2021

Abstract
Using data on the absorption cross sections the refraction coefficient spectral dependence n(E) and the spectra of the remaining optical coefficients (reflection coefficient, phase shift, and atomic form factor) in the fullerite C60 C 1s near edge X-ray absorption fine structure (NEXAFS) region (280–350 eV) were determined. For the n(E) calculations the Kramers-Kronig integral relations (KKRs) were used. The KKR computations were performed using data on atomic carbon absorption cross sections in the 10–30000 eV range and on solid and gaseous C60 – in the 0–120 eV. Absorption cross section spectrum in the fullerite C60 C 1s NEXAFS region were measured.
Investigation of spectral properties of potassium-aluminum-borate glass with CuCl - CuBr nanocrystals
Authors: Babkina A N , Zyryanova K S , Egorova Y B , Kulagina A S , Gavrilov R R , Monogarova A A 
Published: December 2021

Abstract
Heat treatment conditions effect on the characteristics of exciton absorption and luminescence of CuCl and CuBr nanocrystals in potassium-aluminaborate glass is studied. The size effect of the band edge absorption and luminescence energy is confirmed. The simultaneous presence of copper halide nanocrystals and free monovalent copper ions in the glass matrix is shown. Possible conditions for the formation of mixed CuCl-CuBr crystals are considered.
Spectral Fourier-microscopy of the periodic structures based on Ge2Sb2Te5
Authors: Solomonov A I , Pavlov S I , Lazarenko P I , Kovalyuk V V , Golikov A D , Prokhodtsov A I , Goltsman G N , Kozyukhin S A , Dyakov S A , Gippius N A , Tikhodeev S G , Pevtsov A B 
Published: December 2021

Abstract
The method of spectral Fourier microscopy was used to study the reflection spectra with an angular resolution of submicron periodic gratings based on amorphous and crystalline Ge2Sb2Te5. The form of the dispersion curves of quasi-waveguide modes in the structures under study was established. The experimental data were compared with the calculations of dispersion curves in synthesized diffraction gratings. Reasonable agreement between theoretical and experimental data was obtained.
The model of degradation of an InGaN/GaN LED during current tests taking into account the inhomogeneous distribution of the defects density in the heterostructure
Authors: Frolov I V , Hodakov A M , Sergeev V A , Radaev O A 
Published: December 2021

Abstract
A model of the optical power degradation of an InGaN/GaN LED during testing under direct current, which takes into account the inhomogeneous distribution of the defects density in the heterostructure, is presented. According to the simulation results, the rate of degradation of the LED optical power significantly depends on the degree of inhomogeneity of the defects density distribution profile. Experimental testing of the model has been carried out. The proposed model makes it possible to predict the rate of degradation of InGaN-based LEDs with varying degrees of inhomogeneity of the defects density distribution profile and can be used to develop a technique for rejecting defective and potentially unreliable LEDs.
Induced electronic phenomena in crystals of p-GaSe semiconductor promising for optoelectronics
Authors: Babayeva R F 
Published: December 2021

Abstract
An induced impurity photoconductivity by the electric field, thermally stimulated conductivity and spontaneous pulsations of the dark current were found in the undoped (with a dark resistivity P77≈3•104÷108 Ω-cm at T≈77 K) and erbium doped (NEr=10–5÷10–1 at.%) p-GaSe crystals in the temperature range of T≤240÷250 K at electric field strengths (E) creating a noticeable injection. It was found that the value of the observed impurity photoconductivity (M) monotonically increase at low illumination in undoped crystals with increasing P77 and its spectrum smoothly expands towards longer waves. The value of ∆ii
and the width of its spectrum change non-monotonically with increasing NEr
in doped crystal and it gets its maximum value at NEr
≈5•10-4 at.%. The intensity of spontaneous pulsations increases with increasing E at the higher electric field strengths. However, the impurity photoconductivity and the peak of thermally stimulated conductivity gradually disappeared. The amplitude and frequency of the observed spontaneous pulsations of the dark current is increased with increasing in the injection ability of the contacts. Moreover, the pulsations of the dark current gradually disappeared with increasing T. It was shown that all these three phenomena are directly caused by the recharge of sticking levels with a depth
Er
≈+0.42 eV and a density Nt≈ 1015 cm-3 by injected holes. However, in high-resistance undoped and doped
Er

≤10-2 at.% crystals, it is also necessary to consider the presence of random macroscopic defects in the samples to explain their features. A qualitative explanation is proposed based on the obtained results.