bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solar coronal rotation according to soft X-ray solar radiation during the 22nd, 23rd, and 24th solar cycles
Authors: Dmitriev P B 
Published: December 2021

Abstract
Using the developed method of combining numerous scattered time series of the same type of measurements into a single weighted average series, according to the data of the GOES series satellites, a single series of daily data was synthesized during the 22nd, 23rd and 24th solar cycles (1986 – 2019 years). The flare and background components were distinguished from this data series, which were investigated by means the method of constructing a composite spectral periodogram for the presence of quasiperiodic oscillations at various solar cycles. Some of these found quasiperiods may be explained by both synodic and sidereal rotation of the Sun, while others coincide with the average lifetime of the solar atmosphere active formations such as the sunspot groups and the facular plages. Special attention was paid to the study of the change over time the revealed quasiperiodic values over the course of solar cycles by calculating the sample normalized spectral density of the analyzed data in a sliding time window with a value of up to two years. Based on the revealed quasiperiodic value changes presented on the dynamic diagrams, it can be concluded that the differential rotation of the solar corona is unstable and manifests itself only at certain stages of the development and existence of solar activity cycles.
Generation of ultrashort pulses in the THz frequency range
Authors: Oparina Yu S , Savilov A V 
Published: December 2021

Abstract
There are results for the spontaneous coherent super-radiative undulator emission in the terahertz frequency range from a short (as compared to the wavelength of the radiated wave) dense electron bunch. If the group velocity of the wave is close to the bunch velocity, this is a process of spontaneous radiation followed by amplification of a single wave cycle. Despite the Coulomb repulsion of electrons inside the bunch, its compactness is provided by the compression of the bunch under the action of its own radiation fields. As a result, formation of an ultra-short (several cycles long) powerful wave packet occurs when the bunch moves through several undulator periods with high (∼20% in optimized systems) efficiency of extraction of the electron energy and high intensity (∼ 100 MV/m) of the peak wave field.
Kelvin-probe microscopy as a technique of estimation of the charge traps saturation time
Authors: Dementev P A , Dementeva E V 
Published: December 2021

Abstract
In this work, a method for estimating the saturation time of traps in dielectric layers based on the KPM is proposed. Using hafnium oxide layers as an example, it is shown that when charging with a series of points with different durations, a different dependence of the residual potential on time is observed. It is assumed that this technique makes it possible to evaluate the performance of devices based on dielectric layers.
Synthesis and structural characterization of Fe1-xMexBO3 (Me = Al, Sc) single crystals
Authors: Mogilenec Yu , Seleznyova K , Yagupov S , Seleznev K , Nauhatsky I , Maksimova E , Strugatsky M 
Published: December 2021

Abstract
Fe1-xMexBO3 (Me = Al, Sc) single crystals have been synthesized by flux growth technique using B2O3-PbO-PbF2 solvent and approach of identical synthesis conditions. The contents of the diamagnetic ions Me in the initial charge of both compositions were equal, xcharge=0.05. The exact contents and crystal lattice parameters of the synthesized crystals were determined by X-ray fluorescence analysis and X-ray diffraction, respectively.
Interaction of sulfur with impurities in bcc iron
Authors: Verkhovykh A V , Mirzoev A A , Okishev Yu K , Dyuryagina N S 
Published: December 2021

Abstract
In this work, the modeling of the sulfur interaction with substitutional impurities (Mn, P) and interstitial (C) has been carried out. All calculations were performed using the density functional theory in the WIEN2k software package. For the first two coordination spheres, there is a strong repulsion between carbon and sulfur, but in the third relative position, a slight attraction arises between the atoms. When sulfur interacts with manganese, attraction occurs only for the first coordination sphere, while the dissolution energy of both manganese and sulfur decreases. In the case of the S-P interaction, the binding energy is negative, and the dissolution energy of both sulfur and phosphorus decreases for all configurations, although the distance between phosphorus and sulfur increases. It can be assumed that the presence of phosphorus leads to the accumulation of sulfur in the material.
On quantum analogue of instable oscillating states of an inverted oscillator in external poly-harmonic field
Authors: Chistyakov V 
Published: December 2021

Abstract
Nonstationary Schroedinger equation (NSE) is solved analytically and numerically to study a phenomenon of dynamical stabilization of the inverted oscillator driven by polyharmonic in time and spatially uniform force with specially chosen phase shifts. It is shown that for Gaussian wave packet asymptotically fitting the initial condition (IC) it occurs temporary delay of the packet center about top of the parabolic potential for about 2 fundamental time periods followed by the center bifurcation.
The dependence of surface morphology on the growth temperature of the Pb0.7Sn0.3Te/Si(111) topological insulator thin films
Authors: Kaveev A K , Bondarenko D N , Tereshchenko O E 
Published: December 2021

Abstract
The possibility of epitaxial growth of Pb0.7Sn0.3Te crystalline topological insulator films on the Si(111) surface was shown and epitaxial relations were found. It was shown that, depending on the growth temperature, it is possible to control not only the character of the morphology, but also, to a significant extent, the smoothness of the epitaxial layer surface, which is extremely important for further transport measurements of the films. Analysis of the grown films surface morphology made it possible to establish the average value of the height and lateral size of the terraces and islands forming Pb0.7Sn0.3Te surface.
Mechanical frictional scanning probe lithography of TMDCs
Authors: Borodin B R , Benimetskiy F A , Alekseev P A 
Published: December 2021

Abstract
In this work, we investigate mechanical scanning probe lithography (SPL) of thick MoSe2 flakes. The conventional technique faces difficulties in processing the thick samples due to cantilever twisting that leads to the growth of a number of defects and artifacts that decrease spatial resolution. In course of this work, we proposed the approach of frictional-SPL based on small pressure force and many repetitions of lithographic patterns. This approach allows to avoid the formation of remarkable defects and maintain high spatial resolution. By frictional-SPL, we processed thick MoSe2 flakes (up to 40 nm thick) with the highest resolution down to 20 nm. The results of this work show that frictional-SPL is an effective method of resistless lithography suitable for fabricating nanodevices based on transition metal dichalcogenides (TMDC) materials.
Thermal conductivity of PCM materials based on a composite consisting of n-alkane and nanoscale additives
Authors: Borisov A K , Egorov V M , Marikhin V A , Myasnikova L P 
Published: December 2021

Abstract
Composites based on n-alkane and nanoscale additives were investigated to determine the efficiency of heat transfer during phase transitions in phase change materials. It was found that the thermal conductivity of composite materials is several times higher than the thermal conductivity of the initial n-alkane. The observed effect is due to the specificity of the supramolecular nanostructure of the composite, which differs from the supramolecular structure of the nonadecane.
Study of elastic deformations in tapered nanowires
Authors: Dunaevskiy M S , Alekseev P A 
Published: December 2021

Abstract
In this work, the calculation of the values of elastic deformations and stresses arising in tapered nanowires is carried out. It was found that in tapered nanowires the magnitude of deformations changes from the base of the nanowire to its tip not linearly (as would be the case in cylindrical nanowires), but in a more complex manner. The ranges of conicity angles at which an extended region of increased stresses can appear in tapered nanowires have been determined.
Investigation of HIT solar cells low frequency noise characteristics
Authors: Ermachikhin A V , Vorobyov Y V , Trusov E P , Litvinov V G 
Published: December 2021

Abstract
The effect of solar cell fragment annealing on its noise characteristics is shown. The calculated difference in relaxation times arising from the change in noise after annealing was 30%. Measurements of noise characteristics in the dark and under illumination with a red laser with different radiation power were carried out. Close to linear dependences of noise power reduction with increasing radiation power were obtained.
Study of the titanium VT1-0 surface degradation after cyclic loading in different structural states, including ones when coatings are formed by Micro-Arc Oxidation
Authors: Narykova M V , Kadomtsev A G , Betekhtin V I , Kolobov Yu R , Dvorak J , Sklenicka V 
Published: December 2021

Abstract
This article considers the results of the study of the titanium VT1-0 surface degradation (Grade-4 equivalent) for recrystallized- and ultrafine-grained states after fatigue testing. Comparative analysis of peculiarities of the titanium samples degradation was performed after coating formation by Micro-Arc Oxidation. It was found, that the coating formed by Micro-Arc Oxidation shows different degradation behaviors for recrystallized and ultrafine-grained states
Effect of heat treatment on the galvanomagnetic properties of bulk nanostructured samples of Bi85Sb15 solid solution
Authors: Tagiyev M M , Abdinova G D , Abdullayeva I A 
Published: December 2021

Abstract
Extruded bulk nanostructured samples of Bi85Sb15 solid solution from particles with average sizes ∼ 2.105; 950; 650; 380; 30 and 15 nm were obtained and investigated their galvanomagnetic properties in the range of ∼ 77-300 K. Were investigated samples that have not passed heat treatment, and the same samples that have passed heat treatment. It was found that the electrical and thermal properties of Bi85Sb15 solid solution samples significantly depend on the size of nanoparticles and post-extrusion heat treatment. Heat treatment leads to a decrease in the concentration of current carriers and to an increase in the mobility of current carriers and the total thermal conductivity of the samples under study, which is mainly due to the electronic component of thermal conductivity. The change in thermal parameters is satisfactorily explained by changes in occurring in the structure of samples during extrusion and heat treatment and correlates well with changes in the electrical parameters of these processes.
Multiphoton intersubband transitions in an armchair graphene nanoribbon
Authors: Monozon B S , Fedorova T A , Schmelcher P 
Published: December 2021

Abstract
We present an analytical approach to the problem of the interband transitions in an armchair graphene nanoribbon (AGNR), exposed to the time-periodic electric field of strong light wave, polarized parallel to the ribbon axis. The two-dimensional Dirac equation for the massless electron subject to the ribbon confinement is employed. In the resonant approximation the probability of the transitions between the valence and conduction size-quantized subbands are calculated in an explicit form. We trace the dependencies of the Rabi frequency for these transitions on the ribbon width and electric field strength for both the multiphoton-assisted and tunneling regimes relevant to the fast oscillating and practically constant electric field, respectively. Estimates of the expected experimental values for the typically employed AGNR and laser technique facilities show that the Rabi oscillations can be observed under laboratory conditions. The data, corresponding to the intersubband tunneling, makes the AGNR a 1D condensed matter analog, in which the quantum electrodynamic vacuum decay can be detected by the employment of the attainable electric fields.
Average SWCNT bundle length estimated by resistance measurement
Authors: Mitin D M , Vorobyev A.A. , Berdnikov Y S , Mozharov A M , Nasibulin A G , Mukhin I S 
Published: December 2021

Abstract
The length of single-walled carbon nanotubes (SWCNTs) affects the optoelectronic and mechanical properties of macroscopic SWCNT layers. Modern methods are capable to measure the length of short nanotubes, and also require complex sample preparation procedures. In this work we show that the average length of SWCNTs can be estimated by measuring the resistance of randomly oriented SWCNTs array. We observe the change in the slope of the resistance dependence on the distance between the contacts with the interval between 100 and 200 μm. The change of resistance slope indicates a change in the path of current flow through the SWCNT. The change in the conduction path can be associated with the “effective bundle length”, which should be related to the average nanotube length. Thus, we have demonstrated a simple and quick technique to measure SWCNT bundle length, which can be used in-situ and does not require special sample preparation.
144Ce - 144Pr spectrum measurement with 4π semiconductor β-spectrometer
Authors: Alekseev I E , Bakhlanov S V , Derbin A V , Drachnev I S , Kotina I M , Lomskaya I S , Mikulich M S , Muratova V N , Niyazova N V , Semenov D A , Trushin M V , Unzhakov E V 
Published: December 2021

Abstract
Precision β-spectra measurement always had a great importance in some fundamental physics problems including neutrino physics. Magnetic and electrostatic spectrometers have high resolution, but at the same time usage of such kinds of equipment involves the size and cost issues. Since electron mean free path at the energy of 3 MeV (which is basically the maximum energy of a β-transition for the long-lived nuclei) does not exceed 2 g/crn2
, electron registration could be effectively performed with the solid state scintillators and semiconductors. A strong probability of backscattering from detector surface is present in case of semiconductor detectors and is dependent upon the detector material. Such problem can be solved with 4π geometry detector development, which fully covers the radioactive source and is able to register the backscattered electrons. In this work we present the newly developed technology of 4π geometry β-spectrometer based on two semiconductor detectors. This spectrometer was used for measurement of the 144Ce - 144Pr spectrum, that is the perspective anti-neutrino source due to endpoint energy at 3 MeV and can be used for the sterile neutrino search experiments. The form-factor parameters that were obtained are: C(W) = 1 + (-0.02877 ± 0.00028)W + (-0.11722 ± 0.00297)W-1. The measurement accuracy was sufficiently enhanced with respect to the previous results.
Spectral studies of bismuth-containing pyrochlores
Authors: Nekipelov S V , Zhuk N A , Petrova O V , Sivkov D V , Bakina K A , Bogachuk D V , Skandakov R A , Sivkov V N 
Published: December 2021

Abstract
Thermal stable solid solutions of titanates, niobates, and tantalates of bismuth with a pyrochlore structure doped with 3d-metal atoms were studied using XPS and NEXAFS spectroscopy. Based on spectral studies, it was shown that the manganese, cobalt, nickel and copper atoms in these solid solutions have mainly charge state +2 and iron atoms – charge state +3.
A study of the influence of copper sulfate on the spectral properties of common buckwheat (Fagopyrum esculentum)
Authors: Goryainov V S , Buznikov A A 
Published: December 2021

Abstract
The influence of pollutants on the spectral properties of common buckwheat (Fagopyrum esculentum) has been investigated insufficiently, compared to the cereals from the Poaceae family. A two-stage spectral survey has been carried out, growing common buckwheat in containers with set concentrations of copper(II) sulfate in soil both in laboratory conditions and in the open air. Spectral distributions of diffuse reflectance of the plants were registered in the range of 400 – 1100 nm, and spectral indices were calculated, using wavelengths corresponding to spectral features of plant pigments. Simultaneously, digital photos were taken to account for projective cover of the plants. Four spectral indices were found to depend quantitatively on pollutant concentration, three of them taking extreme values at the time of maximal projective cover. When growing buckwheat in the open air, lower temperatures and higher irradiation lead to closer values of spectral indices corresponding to different copper concentration, than in laboratory conditions. The results show the usability of common buckwheat as an indicator of soil pollution by copper.
Interaction of an electromagnetic E-wave with a thin conducting film between two dielectric media in the case of an anisotropic isoenergetic surface and impurity scattering
Authors: Kuznetsova I A , Romanov D N , Yushkanov A A 
Published: December 2021

Abstract
The coefficients of reflection, transmission and absorption are calculated in the framework of the kinetic approach, when an electromagnetic E-wave interacts with a thin conducting film located between two dielectric media. To account for the surface scattering of charge carriers is used a model of mirror-diffuse boundary conditions, assuming that the specularity coefficients of the upper and lower surfaces of the film differ from each other. The electromagnetic wave falls on the upper surface of the film at an arbitrary angle. The case of an anisotropic isoenergetic surface of a conductor having the form of a three-axis ellipsoid, one of the main axes of which is parallel to the magnetic field strength of the wave, and the other is perpendicular to the film surfaces, is considered. The impurity scattering of electrons (holes) is dominated in the volume of the conductor. The dependence of the absorption coefficient on the parameters of the isoenergetic surface of the conductor is analyzed.
Development of a method for quantitative comparison of the luminance of self-glowing crystals – the basic elements of a low current source
Authors: Mjagkih M K , Dementev P A , Zamoryanskaya M V 
Published: December 2021

Abstract
This work is devoted to the development of a method for the quantitative comparison of the luminosity of weakly luminous samples, such as self-glowing crystals. A self-glowing crystal is an efficient scintillator, whose self-luminescence is due to the decay of a radioactive isotope introduced into the crystal matrix during its growth. Such crystals can be used as low current sources with a service life of 50 years or more. This technique takes into account the luminescence spectra of the samples under study, the spectral functions of the spectrometer and photodetector. Information on the luminescence spectra of samples can be obtained based on their cathodoluminescence spectra. Thanks to the calculations performed according to this technique, it becomes possible to estimate the optical radiation power of a self-glowing crystal, which can be converted into an electric current using a photodiode. Also, the proposed technique can be applied to assess the luminosities of any materials under the influence of radioactive radiation.
Spectral analysis of juvenile dentin biomaterials
Authors: Timchenko P E , Timchenko E V , Volova L T , Frolov O O , Vlasov M Y , Shipko S S 
Published: December 2021

Abstract
The experiments in optical evaluation of biomaterials taken from juvenile dentin have been made using the Raman spectroscopy method. It was shown that juvenile teeth lose their mineral components and preserve organic components in the process of demineralization with the use of hydrochloric acid.
Nonstationary holographic currents in a β-Ga2O3 crystal at wavelength λ = 457 nm
Authors: Bryushinin M A , Sokolov I A 
Published: December 2021

Abstract
We report the excitation of nonstationary holographic currents in a monoclinic gallium oxide crystal. Although the crystal is almost transparent and insulating for a visible light, the dynamic space-charge gratings are recorded and holographic currents are observed for both the diffusion and drift modes. The anisotropy along the [100] and [010] directions is revealed, namely, there is a small difference in the transport parameters and a pronounced polarization dependence of the signal. The crystal’s photoconductivity, responsivity and diffusion length of electrons are estimated for the light wavelength λ = 457 nm.
Determination of the refractive index profile and surface topography of optically smooth objects using interference of optical vortices
Authors: Sokolenko B V , Shostka N V , Poletaev D A 
Published: December 2021

AbstractIn this paper, we present the results of the propagational dynamics of vortex beams in the scope of their possible applications for interferometric non-contact robust and precision optical surface profilometry with nanoscale longitudinal resolution. The result of coaxial superposition of the reference plane wave with singly charged vortex beams represents a dynamically changing intensity distribution. The nature of this changes, namely, rotational effects of intensity zeros, allows to determine directly the optical path difference which is introduced by the surfaces and internal structure of test object. We have proposed the experimental setup for examination of reflecting and transmitting objects.
Influence of the aluminum content on the luminescent and electronic properties of β-Ga2O3
Authors: Dementeva E V , Dementev P A , Kremleva A V , Panov D Y , Romanov A E , Bugrov V E , Zamoryanskaya M V 
Published: December 2021

AbstractIn this work, we investigated bulk β-Ga2O3samples grown by the Czochralski method on Al2O3and β-Ga2O3seeds. The elemental composition of the samples and its effect on the luminescent and electrophysical properties of the samples were determined. The Kelvin probe microscopy was used to study the processes of localization and dissipation of charges in the samples. It was shown that in a β-Ga2O3sample grown on an Al2O3seed, the characteristic charge dissipation time is 10 times longer.
Modeling of plasmon resonance of silver nanoparticles on a silicon surface
Authors: Bolshakov V O , Ermina A A , Zharova Yu A , Tolmachev V A 
Published: December 2021

Abstract
Silver nanoparticles have unique optical properties due to resonance effects that arise due to the presence of conduction electrons in them. When these electrons interacte with photons, they can create localization of electric fields at the interfaces with the environment. Silver nanoparticles deposited on a transparent substrate are often used for research, while Ag nanostructures on Si are studied in this work. They have great potential for practical applications. The interaction of light with nanostructures can be described using various models (pseudo-dielectric functions, effective medium, thin-layer structures, etc.) and optical methods for the experimental determination of their parameters (refractometry, spectrophotometry). Bulk plasmon resonance is considered in this work, which is excited when plasmons are excited at their resonant frequency by an external electromagnetic wave. Calculations were performed for different diameters of silver nanoparticles on a silicon substrate with different structure periods. The calculated spectra are in good agreement with the experimental data of the obtained samples. As a result of the plasmon resonance modeling, the position of the plasmon resonance depends on the density of the arrangement of silver nanoparticles, with an increase in the displacement resonance towards the long-wavelength region.