bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of the auroral hiss spatial structure and comparison with the observed results
Authors: Nikitenko A. S. , Fedorenko Yu. V. , Manninen J. , Lebed O. M. , Beketova E. B.
Published: April 2024

We present the results of the auroral hiss propagation modeling from the source region to the ground and its comparison with the observed results. We analyzed propagation conditions explaining locality of the auroral hiss illuminated area observed on the ground. It is shown that quasielectrostatic waves with random amplitudes, phases and wavenormals directions representing the auroral hiss propagating to the ground form two wave beams in the meridional plane. The scattering of these waves at altitudes of 800–1300 km can cause the observed locality of the illuminated area.
Birotons and ‘dark hierarchies’ in fractional quantum Hall effect
Authors: Kulik L. V. , Ваньков А. Б.
Published: April 2024

A computational scheme has been developed to determine the energies of neutral excitations in fractional states of the quantum Hall effect. The fractional states are brought into a general hierarchical system (Farey-number hierarchy structure). It is shown that in addition to the well-known hierarchy of fractional states (Laughlin–Jane), there are other ‘dark hierarchies’ of fractional quantum Hall effect that are not observed experimentally in the most highly mobile samples but can have a significant impact on the thermodynamics and spectral characteristics of fractional quantum Hall effect states. The connection of the ‘dark hierarchies’ of fractional quantum Hall effect with the existing experimental data is considered.
Effect of interface quality on photoluminescence of encapsulated MoSe2 monolayers
Authors: Chernenko A. V. , Brichkin A. S. , Golyshkov G. M. , Shevchun A. F.
Published: April 2024

Photoluminescence spectra of excitons and trions in MoSe2 monolayers encapsulated with hexagonal boron nitride under nonresonant laser excitation were studied. When the size of the laser excitation spot decreases from 8 to 3 nm, individual peaks with a line width of ~2 meV emerge in the photoluminescence spectra, which were unresolved with a larger spot. Studies of the sample surface using a scanning electron microscope revealed the existence of a large number of features at the interfaces of structures with characteristic sizes ranging from submicron to micron and more. It was expected that the lines appearing in the spectrum at small excitation spot sizes were associated with similar submicron inhomogeneities. A study of a specially made heterostructure covered by a metal mask with holes of 1.6 microns in diameter confirmed this assumption.
Proximity effect in ferromagnetic structures InGaAs/GaAs/CoPt
Authors: Zaitsev S. V.
Published: April 2024

Ferromagnetic influence of a thin (~8 nm) surface CoPt layer on the circular polarization of the InGaAs/GaAs quantum well photoluminescence is observed in structure GaAs/InGaAs/GaAs/Al2O3 (1 нм)/CoPt with narrow GaAs spacer dS = 5 nm, while electroluminescence is polarized in the whole range of dS = 5–100 nm. It is suggested that the short-range proximity effect is determined by overlap of electrons wave functions with the nearby ferromagnetic CoPt film.
Numerical investigation of multipactor discharge in coaxial switches
Authors: Dovgan A. A. , Bahteev I. Sh. , Molchanov S. Yu. , Kuzyutkin S. I.
Published: April 2024

Findings in the research on conditions for occurrence of a multipactor discharge in coaxial switches have been presented. A model of a powerful coaxial microwave SPDT switch operating in the frequency range below 1.7 GHz has been obtained. Calculated values of the electrical parameters have been given and the possibility of manufacturing a coaxial switch for spacecraft with an operating power margin has been shown. The manufactured prototype of the microwave switch can withstand at least 400 W of RF power at a frequency of 1 GHz, which has been confirmed by the experiment.
Magnetic and dielectric properties double perovskite Sr2MnTiO5.87
Authors: Eremina R. M. , Chupakhina T. I. , Batulin R. G. , Popov D. V. , Deeva Yu. A. , Mirzorakhimov A. A.
Published: April 2024

Magnetic and dielectric properties of Sr2MnTiO5.87 double perovskite have been studied. Magnetic phase transitions were observed at 12 and 43 K in the FC and ZFC curves of magnetization and magnetic heat capacity, the nature of which is being discussed. From the analysis of the lattice contribution to the specific heat, the Debye and Einstein temperatures were determined, which were θD = 217 К, θЕ1 = 275 К, θЕ2 = 615 К, θЕ3 = 2000 К.
The influence of magnetic film anisotropy on the frequency-modulated signal detection
Authors: Asadullin F. F. , Pleshev D. A. , Vlasov V. S. , Shcheglov V. I.
Published: April 2024

We studied the possibility of using a magnetostriction converter for detecting a microwave signal with frequency modulation. The magnetization vector and elastic displacement oscillations in a normally magnetized ferrite film with crystallographic anisotropy are considered. We analyzed the effect of crystallographic cell orientation on the nature of the magnetization dynamics and elastic displacement oscillations, the establishment of various oscillation modes, and the detection process.
Liquid-crystal composites of carbon nanotubes in a magnetic field: bridging from the molecular-statistical model to phenomenological theory
Authors: Petrov D. A.
Published: April 2024

Based on the thermodynamic potential of the molecular-statistical mean-field theory of liquid-crystal composites of carbon nanotubes, a representation of the free energy in the form of the Landau expansion is obtained. The resulting expansion is compared with the previously proposed phenomenological theories.
Macroscopic helicity of a suspension of chiral magnetic particles based on nematic liquid crystal
Authors: Sokolchik D. P. , Makarov D. V.
Published: April 2024

The basic state of a suspension of chiral ferroparticles based on a nematic liquid crystal is studied when the finite coupling between the impurity and liquid crystal subsystems is considered. An additional contribution to the free energy functional due to the chiral shape of impurity particles, which describes the formation of spontaneous macroscopic helicity of the orientational structure of a nematic liquid crystal, is proposed.
Modeling of the superconducting triplet spin valve with several superconductor layers
Authors: Gaifullin R. R. , Deminov R. G. , Kushnir V. N. , Kupriyanov M. Yu. , Golubov A. A. , Tagirov L. R.
Published: April 2024

Using the matrix method for solving the linearized Usadel equations, the critical temperature and the distribution of singlet pairing components of the superconductor/ferromagnet/superconductor/ferromagnet structure with nonideal boundaries are obtained. A transition from the π- to the 0-phase state between layers of superconductors was obtained with a change in the angle between the magnetizations of ferromagnetic layers in such a structure.
Stability of a skyrmion crystal in a frustrated antiferromagnetic bilayer on a triangular lattice
Authors: Baisheva A. H. , Yuldasheva A. R. , Diep H. T. , Sharafullin I. F. , Nugumanov A. G.
Published: April 2024

We studied the processes of formation and conditions of stability of skyrmion lattices during thermodynamic fluctuations in magnetoelectric films, namely, in a frustrated antiferromagnetic/ferroelectric bilayer on a triangular lattice. We calculate the ground state configurations with given parameters using the steepest descent method. We consider the thermodynamic fluctuations in influence of an external magnetic field on the ground state configurations and phase transitions occurring in the model using Monte Carlo simulation.
Investigation of the features of superconducting spin valve based on Fe/Nb
Authors: Kamashev A. A. , Validov A. A. , Garif’yanov N. N. , Garifullin I. A.
Published: April 2024

We studied new structures of superconducting spin valves of Fe2/Nb/Fe1/CoOx and Fe2/Al2O3/Nb/Al2O3/Fe1/CoOx designs. The operation of these structures is built beyond the classical superconductor/ferromagnet proximity effect. The superconductor/ferromagnet interface in these structures is separated by an additional insulating layer. According to the results of our studies, the Fe2/Al2O3/Nb/Al2O3/Fe1/CoOx structures are the most promising structures for further research.
Creation and investigation of thin-film heterostructures based on Fe/Nb
Authors: Validov A. A. , Nasyrova M. I. , Khabibullin R. R. , Garifullin I. A.
Published: April 2024

Fe/Nb-based thin-film heterostructures prepared under various conditions are studied. Here, Fe/Nb and Fe/Al2O3/Nb structures prepared on MgO and Al2O3 single-crystal substrates at various substrate temperatures during deposition were studied. According to the results of our studies, the structures prepared at high substrate temperatures (600 K) on MgO demonstrate the most stable and, most importantly, reproducible transport properties of the samples.
Properties of percolation channels in planar memristive structures base on epitaxial films of oxide perovskite compounds YBa2Cu3O7 – δ and La1 – xSrxMnO3 – δ
Authors: Rossolenko A. N. , Tulina N. A. , Shmytko I. M. , Ivanov А. А. , Zotov A. V. , Borisenko I. Y. , Sirotkin V. V. , Tulin V. A.
Published: April 2024

The choice of base materials and the use of their functional properties in the development of the structure and elucidation of the mechanism of resistive switching has been analyzed. Mesoscopic heterostructures based on epitaxial oriented 〈001〉 films of high-temperature superconductor YBa2Cu3O7 – δ and doped manganite La1 – xSrxMnO3 – δ, were obtained, and the properties of percolation channels of structures based on these compounds were studied. The effects of “self-adapting electroforming” in microcontact heterostructures based on epitaxial films of manganite are observed. Numerical calculations using the critical electric field model have shown that “self-electroforming” occurs in strong electric fields and a gap structure is formed in the contact zone. This structure provides reproducibility of resistive switching.
Phase transitions in Na(Nb0.9Me0.1)O3 – δ (Me = Bi, Fe) solid solutions
Authors: Ospelnikov O. N. , Barabanova E. V.
Published: April 2024

We investigated the temperature dependence of the permittivity and electrical conductivity of sodium niobate ceramics doped with iron or bismuth in a wide frequency range of the external field. The phase transitions and their characteristics in these solid solutions, as well as the mechanisms of conduction, are determined.
Special features of magnetism in Dy1 – xHoxMnO3
Authors: Matveeva A. N. , Zobkalo I. A. , Pshenichnaia A. G.
Published: April 2024

Crystal and magnetic structures of Dy1 – xHoxMnO3 multiferroic single crystals (x = 0, 0.2) were investigated by the neutron diffraction methods. It is shown that the substitution of Dy by Ho at the level of 20% does not change the crystal symmetry of the compound. Description was made using the Pbnm group down to very low temperatures for both compounds. Within accuracy of the measurements, magnetic ordering does not change the crystal structure. Substitution of Dy by Ho suppresses spontaneous ordering of a rare-earth subsystem with a propagation vector (0 0.5 0). This leads to a situation when two magnetic subsystems, manganese and rare-earth ones, have a coherent incommensurate space propagation.
Complex study of loose cave deposits of the central Asian region using X-ray analysis methods
Authors: Bazarova Е. P. , Sholokhova Yu. N.
Published: April 2024

The elemental and mineral composition of loose sediments from the Kan-i-Gut mine-cave (Central Asia) was compared. The obtained concentrations of Mn, Fe, and Zn agree with the minerals determined in the composition of samples from the middle and lower horizons. Increased concentrations of Y, as well as the correlation of this element with As in the researched samples were revealed, which gives grounds to assume the presence of yttrium arsenates in the loose formations. The mineral associations found in the mine-cave indicate the formation of the original karst cavity during sulfuric acid speleogenesis. The mineral gergeite was identified in this site for the first time.
Correction of the phase error of a superconducting undulator
Authors: Kanonik P. V. , Shkaruba V. A. , Volkov A. A. , Erokhin A. I. , Zorin A. V. , Kazantsev F. P. , Mezentsev N. A. , Tarasenko O. A. , Khrushchev S. V. , Tsukanov V. M.
Published: April 2024

We described a method of magnetic field correction for a superconducting undulator with neutral poles manufactured in the INP, as well as a mathematical apparatus predicting additional power currents for magnetic field correction. When correcting the field and orbit inside the undulator, the main windings of the undulator are used, grouped into separate groups and powered by additional currents. The test of this correction scheme was carried out, as well as a comparison of theoretical and experimental data of the measured magnetic field and calculated phase errors. In the SPECTRA program, the SI spectra were calculated before and after correction.
The electron beam of the linear induction accelerator with kiloampere current as a driver for the submillimeter free electron laser
Authors: Sandalov E. S. , Sinitsky S. L. , Arzhannikov A. V. , Nikiforov D. A. , Skovorodin D. I. , Pavlyuchenko V. A. , Ginzburg N. S. , Peskov N. Yu. , Protas R. V. , Karasev D. Yu.
Published: April 2024

The project of a submillimeter free electron laser (FEL) based on a relativistic electron beam (REB) generated in a linear induction accelerator (LIA) was proposed at the BINP SB RAS together with the IAP RAS. According to our theoretical analysis, the electron beam generated in the LIA (energy \({{E}_{e}} = 5{\text{--}}10\) MeV, current \({{I}_{b}} = 1{\text{--}}2\) kA, normalized emittance \({{\varepsilon }_{n}}\) ~ 1100 π · mm · mrad) is a suitable driver for generating sub-GW pulses of coherent EM radiation in submm range (0.3–1 THz). The main proposals for the creation of the FEL based on the electron beam generated in the LIA are presented, the main project tasks are outlined, and the proposed methods for their solution are described. The results of electron-optical experiments on the formation of an electron beam intended for FEL applications are presented.
Features of Cl K-edge XANES spectra of metal transition complexes {MCl6}n– (M = Rh, Pd, Re, Os, Ir, Pt)
Authors: Fedorenko A. D. , Asanov I. P. , Asanova T. I. , Vasilchenko D. B. , Nikolenko A. D. , Piminov P. A. , Karyukina K. Yu.
Published: April 2024

Cl K-edges of a set of chlorides of 4d- and 5d-transition metals {MCl6}n– (M = Rh, Pd, Re, Os, Ir, Pt) were obtained using the “Cosmos” station of the VEPP-4 synchrotron. The combined use of experimental X-ray and theoretical methods made it possible to determine the magnitude of the spin-orbit interaction (SOC) depending on the transition metal. The features of the Cl K-edge are analyzed with and without SOC, as well as stretched and compressed complexes.
SR-XRFA in botanical research: the element composition of the Altai Mountain plants (family Fabaceae)
Authors: Khramova E. P. , Syeva S. Ya. , Rakshun Ya. V. , Sorokoletov D. S.
Published: April 2024

A study has been made for the first time on the element composition of both the plants of three species, growing in the Chuyskaya Basin of Altai Mountain, and the samples of soil from their habitat using the method of X-ray fluorescence analysis, involving synchrotron radiation (SR-XRFA). The accumulation of elements depends on plant species, life form and growing conditions. The data obtained on the elemental composition of plant samples and soils can be included in databases.
Patterns of effect of spark plasma sintering temperature on microstructure of thermoelectric composites based on Bi2Te2.1Se0.9Bi2 matrix with cobalt inclusions
Authors: Zhezhu M. , Vasil’ev A. E. , Ivanov O. N.
Published: April 2024

Effect of spark plasma sintering temperature on the formation of Co filler particles in the Bi2Te2.1Se0.9 matrix has been examined. Owing to high-temperature diffusion redistribution of atoms in the matrix and filler materials and chemical interaction between these materials, in the Bi2Te2.1Se0.9 + 0.33 wt % Co, core–shell filler particles (Co@CoTe2) are formed. With increasing the sintering temperature, fraction of the “CoTe2 shell” in the particles increases, while fraction of the “Co core” decreases. This behavior is due to an increasing in the diffusion coefficient of Co in the Bi2Te2.1Se0.9 matrix with increasing in the sintering temperature. The concentration profiles of the Co distribution of in the Bi2Te2.1Se0.9 matrix, governed by diffusion, are well described using Fick’s second law for diffusion from a limited source of a diffusing substance. The diffusion coefficient of Co increases with increasing un the sintering temperature in accordance with the Arrhenius law and with an activation energy of ~0.61 eV.
Surface emitting quantum-cascade lasers with a second-order grating and increased coupling coefficient
Authors: Babichev A. V. , Kolodeznyi E. S. , Gladyshev A. G. , Kharin N. Yu. , Petruk A. D. , Panevin V. Yu. , Voznyuk G. V. , Mitrofanov M. I. , Slipchenko S. O. , Lyutetskii A. V. , Evtikhiev V. P. , Karachinsky L. Ya. , Novikov I. I. , Pikhtin N. A. , Egorov A. Yu.
Published: April 2024

The results of studying the characteristics of surface-emitting quantum-cascade ring lasers with a second-order grating are presented. The selection of etching receipt by ion beam lithography made it possible to increase the coupling coefficient to 12 cm–1. Lasing close to 7.6 μm with a low threshold current density (about 0.3 kA/cm2) is demonstrated.
Polaron effects created by interface phonons in thin film on ionic substrates
Authors: Maslov A. Yu. , Proshina O. V.
Published: April 2024

The effective parameter of the electron-phonon interaction in a semiconductor film on ionic substrates has been determined. It is shown that interface phonons “transfer” the polarization of the medium from the substrate to the film. As a result, the polaron binding energy and the effective mass of carriers in the same film on different substrates can vary by tens or even hundreds of percent. Conditions for the realization of strong interaction for various films are found.
Orbital detector of ultra-high-energy cosmic rays: status and prospects of the KLYPVE project
Authors: Belov A. A. , Klimov P. A. , Sharakin S. A. , Zotov M. Yu.
Published: April 2024

KLYPVE (K-EUSO) is a planned space experiment aimed at studying ultra-high-energy cosmic rays by detecting fluorescent and Cherenkov radiation from extensive air showers in the Earth’s night atmosphere from near-Earth orbit. The observatory is being developed as a part of the JEM-EUSO program. The registration threshold will be about 50 EeV, and the annual statistics of events will be more than 50. The KLYPVE mission can significantly supplement the data of ground-based experiments.
Study of anomalous events in the TUS experiment
Authors: Lavrova M. V. , Blinov A. V. , Grinyuk A. A. , Tkachev L. G. , Tkachenko A. V.
Published: April 2024

The results of the TUS experiment on search and study extremely high-energy cosmic rays with energies E 70 EeV are analyzed. The TUS detector registered several unusual events of the unclear origin. The analysis of not like EAS and these unique anomalous events is presented.
Interpretation of fluxes of cosmic rays’ nuclei and electrons in the nonclassical diffusion model
Authors: Lagutin A. A. , Volkov N. V. , Raikin R. I.
Published: April 2024

We discuss new scenario of the formation of the observed spectra of electrons/positrons and nuclei of ultrahigh-energy cosmic rays in the framework of the nonclassical (superdiffusion) model of particles propagation in a highly inhomogeneous interstellar and intergalactic media. It is shown that the proposed scenario provides a consistent description of the experimental data of precision satellite measurements, ground-based hybrid EAS arrays and Cherenkov telescopes on the spectra of leptons and nuclei, as well as the mass composition of cosmic rays in the range of super-high and ultrahigh energies.
Input of nearby sources in spectra and anisotropy of ultrahigh energy cosmic rays
Authors: Zirakashvili V. N. , Ptuskin V. S. , Rogovaya S. I.
Published: April 2024

Propagation of ultrahigh energy cosmic rays from nearby sources was investigated. It is shown that observable spectrum, chemical composition and anisotropy at energies above 5 · 1018 eV can be explained in the model of one nearby source galaxy M87 with heavy chemical composition.
Main results of the TUNKA-GRANDE experiment
Authors: Monkhoev R. D. , Astapov I. I. , Bezyazeekov P. A. , Bonvech E. A. , Borodin A. N. , Budnev N. M. , Bulan A. V. , Vaidyanathan A. , Volkov N. V. , Volchugov P. A. , Voronin D. M. , Gafarov A. R. , Garmash A. Yu. , Grebenyuk V. M. , Gress E. O. , Gress O. A. , Gress T. I. , Grinyuk A. A. , Grishin O. G. , Dyachok A. N. , Zhurov D. P. , Zagorodnikov A. V. , Ivanova A. D. , Ivanova A. L. , Iliushin M. A. , Kalmykov N. N. , Kindin V. V. , Kiryuhin S. N. , Kokoulin R. P. , Kolosov N. I. , Kompaniets K. G. , Korosteleva E. E. , Kozhin V. A. , Kravchenko E. A. , Kryukov A. P. , Kuzmichev L. A. , Chiavassa A. , Lagutin A. A. , Lavrova M. V. , Lemeshev Yu. E. , Lubsandorzhiev B. K. , Lubsandorzhiev N. B. , Malakhov S. D. , Mirgazov R. R. , Okuneva E. A. , Osipova E. A. , Pakhorukov A. L. , Pan A. , Panov A. D. , Pankov L. V. , Petrukhin A. A. , Podgrudkov D. A. , Popova E. G. , Postnikov E. B. , Prosin V. V. , Ptuskin V. S. , Pushnin A. A. , Razumov A. Yu. , Raikin R. I. , Rubtsov G. I. , Rjabov E. V. , Samoliga V. S. , Satyshev I. , Silaev A. A. , Silaev A. A. , Sidorenkov A. Yu. , Skurikhin A. V. , Sokolov A. V. , Sveshnikova L. G. , Tabolenko V. A. , Tanaev A. B. , Tarashansky B. A. , Ternovoy M. Yu. , Tkachev L. G. , Ushakov N. A. , Chernov D. V. , Yashin I. I.
Published: April 2024

The Tunka-Grande scintillation array is described. The scientific results obtained during the first 5 years of its operation are presented. The prospects for studying cosmic rays in the energy range 1016–1018 eV are discussed.
The energy spectrum of gamma-rays from the Crab Nebula according to the TAIGA astrophysical complex
Authors: Volchugov P. A. , Postnikov E. B. , Astapov I. I. , Bezyazeekov P. A. , Bonvech E. A. , Borodin A. N. , Budnev N. M. , Bulan A. V. , Vaidyanathan A. A. , Volkov N. V. , Voronin D. M. , Gafarov A. P. , Gress E. O. , Gress O. A. , Gress T. I. , Grishin O. G. , Garmash A. Yu. , Grebenyuk V. M. , Grinyuk A. A. , Dyachok A. N. , Zhurov D. P. , Zagorodnikov A. V. , Ivanova A. D. , Ivanova A. L. , Iliushin M. A. , Kalmykov N. N. , Kindin V. V. , Kiryuhin S. N. , Kokoulin R. P. , Kolosov N. I. , Kompaniets K. G. , Korosteleva E. E. , Kozhin V. A. , Kravchenko E. A. , Kryukov A. P. , Kuzmichev L. A. , Chiavassa A. , Lagutin A. A. , Lavrova M. V. , Lemeshev Yu. E. , Lubsandorzhiev B. K. , Lubsandorzhiev N. B. , Malakhov S. D. , Mirgazov R. R. , Monkhoev R. D. , Okuneva E. A. , Osipova E. A. , Panov A. D. , Pakhorukov A. L. , Pan A. , Pankov L. V. , Petrukhin A. A. , Podgrudkov D. A. , Popova E. G. , Prosin V. V. , Ptuskin V. S. , Pushnin A. A. , Razumov A. Yu. , Raikin R. I. , Rubtsov G. I. , Rjabov E. V. , Samoliga V. S. , Satyshev I. , Silaev A. A. , Silaev A. A. , Sidorenkov A. Yu. , Skurikhin A. V. , Sokolov A. V. , Tabolenko V. A. , Tanaev A. B. , Tarashansky B. A. , Ternovoy M. Yu. , Tkachev L. G. , Ushakov N. A. , Chernov D. V. , Yashin I. I. , Sveshnikova L. G.
Published: April 2024

We studied the spectrum of gamma-rays from the Crab Nebula in the energy range of 4–100 TeV, obtained from the data of two atmospheric Cherenkov telescopes, as part of the TAIGA complex. We described a technique for selection and reconstruction of gamma-rays energy, including a procedure for reconstruction the energy spectrum.
Multicomponent extensive air showers studies at the installations of the experimental complex NEVOD
Authors: Amelchakov M. B. , Bogdanov A. G. , Gromushkin D. M. , Dmitrieva A. N. , Kokoulin R. P. , Konovalova A. Yu. , Nugaeva K. R. , Petrukhin A. A. , Pochestnev A. D. , Khokhlov S. S. , Shulzhenko I. A. , Yuzhakova E. A.
Published: April 2024

Results of the analysis of the parameters of extensive air showers detected by the installations of the Experimental Complex NEVOD, as well as the results of their comparison with simulated events are presented. The calibration and energy threshold of the NEVOD-EAS air-shower array, as well as the results of reconstructing the axes direction according to the data the NEVOD-EAS and DECOR installations are discussed. An example of the event detected by all installations of the complex is given.
The deep-water BAIKAL-GVD telescope follow-up analysis of the IceCube neutrino alerts
Authors: Avrorin A. V. , Avrorin A. D. , Aynutdinov V. M. , Allakhverdyan V. A. , Bardačová Z. , Belolaptikov I. A. , Borina I. V. , Budnev N. M. , Gafarov A. R. , Golubkov K. V. , Gorshkov N. S. , Gress T. I. , Dvornický R. , Dzhilkibaev Zh.-A. M. , Dik V. Ya. , Domogatsky G. V. , Doroshenko A. A. , Dyachok A. N. , Elzhov T. V. , Zaborov D. N. , Kebkal V. K. , Kebkal K. G. , Kozhin V. A. , Kolbin M. M. , Konischev K. V. , Korobchenko A. V. , Koshechkin A. P. , Kruglov M. V. , Kryukov M. K. , Kulepov V. F. , Malyshkin Yu. M. , Milenin M. B. , Mirgazov R. R. , Nazari V. , Naumov D. V. , Petukhov D. P. , Pliskovsky E.N. , Rozanov M. I. , Rushay V. D. , Ryabov E. V. , Safronov G. B. , Seitova D. , Sirenko A. E. , Skurikhin A. V. , Solovjev A. G. , Sorokovikov M. N. , Stromakov A. P. , Suvorova O. V. , Tabolenko V. A. , Tarashansky B. A. , Fajt L. , Khatun A. , Khramov E. V. , Shaybonov B. A. , Shelepov M. D. , Šimkovic F. , Štekl I. , Eckerová E. , Yablokova Yu. V.
Published: April 2024

The main goal of the Baikal-GVD deep-sea neutrino telescope is to detect high-energy neutrinos of astrophysical origin by reconstruction of muon tracks or showers of particles generated in interactions of neutrino with water. Since September 2020, Baikal-GVD has been monitoring IceCube telescope alerts about detection of neutrinos with the energy over 100 TeV. When follow-up analysis is carried out in real time, the delay between an IceCube notification and Baikal-GVD analysis does not exceed three minutes. The fast follow-up is complemented by an offline search for coincidences in time intervals of ±1 and ±12 h with refinement of event’s reconstruction. In the absence of a coincidence or in a case of a single coincidence, the value of expected background is calculated and upper limits on the neutrino flux are set.
Preliminary results of the search for helium nuclei in solar energetic events measured in the PAMELA experiment
Authors: Pavlenko D. V. , Rodenko S. A.
Published: April 2024

We presented the preliminary results of the search for helium nuclei in solar energetic events measured in the PAMELA experiment in the rigidity range from 0.1 to 1 GV from 2006 to 2014. We constructed selection criteria for helium nuclei and estimated their efficiency. The spectra are approximated using a simple power-law function and functional form based on Ellison-Ramaty, consisting of a power-law spectrum modulated by an exponential.
Analysis of variations in concentration of radon decay products in near surface layer of the atmosphere
Authors: Lagutkina A. A. , Dzhappuev D. D. , Kudzhaev A. U. , Kuleshov D. A. , Kurinov K. O. , Miklailova O. I. , Stenkin Yu. V. , Shchegolev O. B.
Published: April 2024

In the last few years an increase in the amplitude of seasonal pressure wave and heavy radioactive nuclides concentration at Baksan Neutrino Observatory of INR RAS in the North Caucasus is being observed. The foregoing tendency, as well as the anomalies observed in the detectors data in autumn-winter, 2017 and winter-spring, 2021 are investigated. Hypotheses of the anomalies reasons and their connection to observed trends are presented.
Study of the mechanisms of hadron-nuclear interactions on the positive beam line 18 of U-70 accelerator
Authors: Gorin A. M. , Evdokimov S. V. , Zaitsev A. A. , Izucheev V. I. , Kondratyuk E. S. , Polishchuk B. V. , Rykalin V. I. , Sadovsky S. A. , Kharlov Yu. V. , Shangaraev A. A.
Published: April 2024

The upgrade project of the experimental setup Hyperon-M, located at the positive beam line of the U-70 accelerator complex in Protvino, is presented with the aim to study the mechanisms of hadron-nuclear interactions. It is proposed to upgrade the setup so that to study the excited states of secondary nuclei formed because of different types of primary hadron-nuclear interactions using precision nuclear gamma-ray spectroscopy. Potentially, this opens a new direction in nuclear physics at the junction with the physics of elementary particles at intermediate energies.
Geant4 FTF model description of the NA61/SHINE collaboration data on strange particle production in pp-interactions
Authors: Uzhinsky V. V. , Galoyan A. S.
Published: April 2024

The latest data by the NA61/SHINE collaboration on inclusive distributions of K*0 and ϕ meson’s, Ξ– and anti-Ξ+ hyperon’s production in pp interactions at Plab from 40 up to 158 GeV/c are considered. As it was shown before in experimental papers, Monte Carlo models – EPOS 1.99, UrQMD 3.4 and Pythia 6, cannot describe reasonably well the data. In the presented paper, the yields of the particles are analyzed within the framework of the Geant4 FTF model. A good description of the experimental data has been reached.
Dynamics of potential difference changes in a biocomposite microsection for different temperature gradients
Authors: Kamalova N. S. , Matveev N. N. , Evsikova N. Yu. , Lisitsyn V. I.
Published: April 2024

The method of formalized modeling revealed the complex nature of the dependence of the parameters of the process of rearrangement of the biocomposite microstructure on the temperature gradient. Based on the analysis of the dynamics of changes in the potential difference formed along the thickness of the birch wood microcut, the parameters of the biocomposite polarization process for various temperature gradients have determined.
Nonlinear and relaxation processes in piezoceramics in weak electric fields
Authors: Shvetsova N. A. , Shvetsov I. A. , Petrova E. I. , Reznichenko A. N. , Rybyanets A. N.
Published: April 2024

We study the effects of piezoelectric hysteresis and relaxation induced by a weak constant electric field in ferroelectric ceramics. Using the piezoelectric resonance analysis method and program, precision measurements of the impedance spectra for thickness and radial vibrations of thin piezoceramic disks were performed for various polarities of the applied constant electric field and polarization of the piezoceramic. An analysis of the field and time dependences of the complex piezoelectric constants of piezoceramics obtained by processing sequentially measured impedance spectra is carried out, and a physical interpretation of the results is proposed.
Glass formation processes in fullerene mixtures
Authors: Khairullina R. R. , Khusnutdinoff R. M.
Published: April 2024

The local structural features of the A20B80 fullerene mixture (where A = C60 and B = C70) are studied by the molecular dynamics simulations for a wide temperature range, including the phase of an equilibrium liquid phase and a supercooled melt, in order to elucidate the mechanism of formation of the icosahedral short-range order in binary molecular liquids. Structural and cluster analyzes revealed the presence of icosahedral clusters in the supercooled melt phase and determined the critical glass transition temperature.
Synthesis of Low Molecular Weight Butadiene Polymers Using Cationic Catalytic Systems Based on Diethylaluminium Chloride
Authors: Rozentsvet V. A. , Ulyanova D. M. , Sablina N. A. , Brunilin R. V. , Tolstoy P. M.
Published: April 2024

Сationic polymerization of butadiene with the catalytic systems based on diethylaluminium chloride (AlEt2Cl) in combination with tertiary alkyl halides (AH), such as tert-butyl chloride, tert-butyl bromide and 2-chloro-2-methylbutane, is an effective method for obtaining fully soluble butadiene polymers at a industrially relevant temperature of 20°C. It is shown that, regardless of the nature of AH in the catalytic system, with an increase in the duration of the polymerization process of butadiene, the values of the weight-average molecular weight and polydispersity of the polymers significantly increase with the simultaneous decrease of polybutadiene unsaturation, which is associated with the transfer reaction of the growing chain to the polymer double bond during polymerization. Using the 13C NMR spectroscopy method, it was found that polybutadiene macromolecules synthesized on the AlEt2Cl–tert-butyl chloride catalytic system consist mainly of 1,4-trans units, contain two types of initial tert-butyl units and two types of end chlorine-containing units formed as a result of the transfer reaction of the growing chain to tert-butyl chloride. Based on the data of 13C NMR spectra of polybutadiene, a method for calculating the conversion of butadiene during polymerization has been developed, and a mechanism of the process of cationic butadiene polymerization has been proposed. It is shown that the synthesized “cationic” polybutadiene is characterized by high film-forming properties and can be a promising component in the production of paint and varnish materials.
Delopment of Composite Carbon–Silicate Materials, Their Research and Testing for the Preparation of Heterogeneous Biocatalysts for Low-Temperature Synthesis of Esters
Authors: Kovalenko G. A. , Perminova L. V. , Goidin V. V. , Zavorin A. V. , Moseenkov S. I. , Kuznetsov V. L.
Published: April 2024

Composite carbon–silica materials (CCSM), differing in the content of carbon and silica components, were obtained using two silicon dioxide precursors (silica sol and silane) and multi-walled carbon nanotubes (MWNTs). At the initial stage of obtaining CCSM by method 1, impregnation of finely dispersed MWCNT powder with silica sol was used, method 2 was carried out using treatment of MWCNTs with tetraethoxysilane followed by hydrolysis and polycondensation. The content of silica (SiO2) in the composites varied from 3 to 60 wt %. After drying and appropriate heat treatment at 250–350°C, the composite materials were studied by various physicochemical methods: nitrogen porosimetry, electron microscopy, X-ray fluorescence analysis, and synchronous thermal analysis. Significant differences in parameters were found depending on the chemical composition of CСSM, including textural characteristics. Thus, with an increase in the SiO2 content, the specific surface area of composite materials increased (by a factor of 2), and maxima were observed on the distribution curves over pore diameters (at 20–40 nm).The composite carbon–silica materials were tested as adsorbent for the preparation of heterogeneous biocatalysts (BC) for the low-temperature synthesis of esters; the active component of these BC was lipase immobilized exclusively on the carbon surface of nanotubes. With a decrease in the content of MWCNTs in the composite materials, the enzymatic activity and operational stability of biocatalysts, measured in the reaction of esterification of heptanoic acid (C7) with butanol (C4), decreased monotonically, reaching a 2–8-fold drop in activity at the maximum content of SiO2 (58 wt %).
Kinetic Peculiarities of Nucleic Acid Elongation as a Multistage Cosequent Enzymatic Reaction
Authors: Lukovenkov A. V. , Bykov V. I. , Varfolomeev S. D.
Published: April 2024

The article investigates kinetics of nucleic acid elongation as a multistage consequent reaction curling up to cycle. There is represented a matematically precise proof of empiric formulae used to estimate elongation time depending on nucleotide chain length. There are given some estimations of characteristic elongation time for typical chain lengths, for example for new coronavirus (SARS-nCoV-2). There is also investigated stability of elongation kinetics and at typical chain lenghts is shown an existance of instable oscillating solution component in addition to main exponential component.
Research of Kinetic Features of Hydrodesulfurization, Hydrodenitrogenation, and Hydrogenation of Heavy Petroleum Compounds on Sulphide Ni6PMonW(12 – n)/Al2O3 Hydrotreating Catalysts
Authors: Moiseev A. V. , Maximov N. M. , Solmanov P. S. , Tyshchenko V. A.
Published: April 2024

Kinetic studies of hydrodesulfurization and hydrodenitrogenation reactions were carried out, as well as a comparison of the hydrogenating activity of the synthesized Ni6PMonW(12 – n)/Al2O3 catalysts and an industrial reference catalyst in the process of hydrotreating of heavy mixed oil feedstock. As it was shown, the HDS reaction is described by a pseudosecond order equation, while the HDN reaction is described by a pseudofirst order. The obtained hydrogenates meet the requirements for the quality of feedstock of catalytic cracking plants in terms of coking capacity, sulfur and nitrogen content.
Ammonia Decomposition Over Cobalt-Based Silica-Supported Fischer-Tropsch Synthesis Catalysts
Authors: Yakovenko R. E. , Krasnyakova T. V. , Saliev A. N. , Shilov M. A. , Volik A. V. , Savost’yanov A. P. , Mitchenko S. A.
Published: April 2024

Decomposition of ammonia over silica-supported cobalt catalysts for Fischer–Tropsch synthesis has been studied at a pressure of 0.1 MPa, a gas hourly space velocity range of 1000–6000 h–1 and a temperature range of 400–650°C in a tubular fixed bed reactor in a flow-through mode. It was found that silica-supported cobalt catalysts for hydrocarbons synthesis via the Fischer–Tropsch protocol also exhibit high activity in ammonia decomposition. Both activity and hydrogen productivity decrease in the series: Co–Ru/SiO2  Co–Al2O3/SiO2 Ru/SiO2 Co–Al2O3/SiO2(35%)/ZSM-5(30%)/Al2O3(35%). The relatively low values of effective activation energies estimated for all catalysts indicate that the reaction can proceed with a high conversion at moderate temperatures.
Mechanism and Kinetic Laws of Reactions Determining Flame Propagation, Gas Explosion and Detonation. Review
Authors: Azatyan V. V.
Published: April 2024

It has been established that, contrary to previous ideas chemical processes in the propagation of flame, explosion and detonation of gases, are chain reactions proceeding according to previously unknown laws of non-isothermal chain processes. The characteristic reaction times in deflagration and detonation in the combustion zone are less than a ten-thousandth and a millionth of a second, respectively. The features of the mechanisms and laws that determine such high rates and accelerations of reactions, their extremely strong temperature dependence is revealed. Using kinetic and spectroscopic methods, the decisive role of atoms and radicals, which are formed in concentrations reaching tens of percent of the concentrations of the initial reagents, is shown. Efficient chemical methods for controlling all combustion modes have been developed.
Vietnamese Montmorillonite Supported ZnO: Preparation, Characterization and Photocatalytic Enhancement in Degradation of Rhodamine B
Authors: Dao Tam Thi Bang , Ha Loan Thi Thu , Nguyen Do Trung , Le Nhien Hon , Luu Quoc Kien , Nguyen Truong Huu , Ha-Thuc Chi-Nhan
Published: April 2024

In this paper, montmorillonite/ZnO (MMT/ZnO) nanocomposite materials are prepared through chemical method with zinc nitrate and sodium alginate as precursors and stabilizers, respectively. Synthesized photocatalysts are used to degrade rhodamine B (RhB) in dye wastewater. The characteristics of photocatalysts in composition, surface morphology and structure are studied by using energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD.The intermediates after decomposition are identified by liquid chromatography–mass spectrometry (LC-MS). The results reveal that zinc oxide nanoparticles (ZnONP) with hexagonal wurtzite structure are successfully attached to montmorillonite layers according to the pillar-montmorillonite structure. The degradation efficiency of 10 ppm RhB in the presence of 0.1g/L MMT/ZnO under UVC irradiation for 210 min reaches 95.5%. The photocatalytic enhancement of MMT for ZnO is evaluated with different operational parameters such as excitation source, solution pH, catalyst content, initial solution concentration and inorganic scavengers. The mechanism of the photocatalytic degradation of RhB by MMT/ZnO is briefly discussed in this study.
MIL-100(Fe)/Diatomite Composites for Photo-Fenton Degradation of Phenol
Authors: Matskan P. A. , Evdokimova E. V. , Mamontov G. V.
Published: April 2024

Porous materials based on metal-organic framework MIL-100(Fe) and diatomite were synthesized. Composites possess specific surface area of 322 and 441 m2/g and hierarchical porous structure with broad pores of diatomite and narrow pores of MIL-100(Fe) particles. Influence of synthesis strategy on structure of materials and their catalytic properties in photocatalytic degradation of phenol was investigated. Composite obtained with preliminary wet impregnation of iron nitrate solution show predominant formation of MIL-100(Fe) particles inside the pores of diatomite. Materials demonstrate catalytic activity in phenol degradation by photo-Fenton process. Composite synthesized without preliminary wet impregnation displays highest catalytic activity with predominant formation of MIL-100(Fe) particles on external surface of diatomite.
Catalysts for Liquid-Phase Oxidation of Organic Compounds by Hydrogen Peroxide: Homogeneous and Phase-Transfer Systems
Authors: Pai Z. P. , Parmon V. N. , Bukhtiyarov V. I.
Published: April 2024

The review presents a comparative analysis of promising homogeneous metal complex catalysts and presents the results of studies on the synthesis and determination of the structural characteristics of effective catalysts for the oxidation of organic compounds with hydrogen peroxide – Q3{PO4[WO(O2)2]4} (Q is a quaternary ammonium cation) – using methods EXAFS, SAXS, NMR, Raman and IR spectroscopy. The possibilities of using bifunctional homogeneous peroxopolyoxo complexes of metals in combination with organic cations having quaternized nitrogen under the conditions of interfacial catalysis are considered, using examples of reactions of oxidation of various classes of organic compounds with hydrogen peroxide to obtain popular products – aliphatic and aromatic epoxides, mono- and dicarboxylic acids, as well as biologically active compounds for medical and agro-industrial purposes.
“Golden Age” of Homogeneous Catalytic Chemistry of Alkynes: Oxidative Тransformations of Alkynes. Review
Authors: Temkin O. N.
Published: April 2024

The methods of carrying out the coupling reactions in the alkynes chemistry were analyzed and generolyzed. Formation of C–C bonds in the reactions of oxidative dehydrocondensation, Kadio–Chodkevich and Sonogashira were considered. The protocols of these reactions were presented. The accent was made on the results of kinetic and spectrometric investigations of coupling reaction mechanisms with participation of Cu(I, II, III), Au(I, III), Pd(O, I, II), and Fe(O, I, II, III) complexes. The special attention was payed to heterogeneous catalysis of oxidative reactions of alkynes with participation of nanoparticles and nanoclusters of Pd, Au, Ag and other metals. The nature of intermediates with the complexes of Cu, Au, Pd and Fe and mutuality of different oxidative and nonoxidative transformations of alkynes were discussed.
XPS Study of the Preparation of Single-Site Catalysts Based on Ir(I) and Rh(I) Complexes Immobilized on a SiO2 Surface Using a P-Containing Linker
Authors: Smirnov M. Yu. , Kovtunova L. M. , Kalinkin A. V. , Skovpin I. V. , Koptyug I. V. , Bukhtiyarov V. I.
Published: April 2024

Samples of model single-site iridium and rhodium catalysts were synthesized by immobilization of complexes [Ir(COD)(IMes)Cl] and [Rh(COD)(IMes)Cl], where COD is cyclooctadiene-1,5 and IMes is 1,3‑bis(2,4,6-trimethylphenyl)imidazol-2-ylidene, on the surface of silicon dioxide modified with a linker containing diphenylphosphine group (Ph2P). Silicon plates with a flat surface covered with a layer of natural oxide 1–3 nm thick, Si-SiO2(nat), or with a specially grown SiO2 film (∼300 nm), Si-SiO2(ox), were used as supports. The chemical compositions of the surface of the modified silicon plates and samples of model catalysts were characterized by XPS. Based on these XPS studies, a tentative conclusion was made about the coordination of immobilized complexes to the SiO2 surface. Catalyst samples were tested in the gas-phase hydrogenation of propene with parahydrogen.
Flow Structure and Transition to Local Turbulence Downstream of an Asymmetric Narrowing that Imitates Arterial Stenosis
Authors: Molochnikov V. M. , Dushin N. S. , Pashkova N. D. , Gataulin Ya. A. , Smirnov E. M. , Yukhnev A. D.
Published: April 2024

The results of experimental studies and numerical simulation of the flow structure in the separation region downstream of an asymmetric narrowing of smooth canal that simulates 70% onesided stenosis of the artery are presented. The Reynolds number was equal to 1800. The instantaneous flow velocity vector fields were measured using the SIV technique. The numerical solution was obtained by the large eddy simulation (LES) method. Setting the disturbances in numerical simulation close to the experimental conditions made it possible to obtain a satisfactory agreement between the calculated and experimental velocity fields and the components of the Reynolds stress tensor. The data on formation of the local flow turbulence region behind the constriction and subsequent downstream flow relaminarization are obtained. It is shown that a pair of secondary eddies localized within the region of flow separation is formed near the throat of the constriction.
Optimal Control of the Angular Momentum for a Solid (Spacecraft) Performing a Spatial Turn
Authors: Levskii M. B.
Published: April 2024

A quaternion solution of the dynamic problem on the optimal turn of a solid (for example, a spacecraft) from a known initial to a given final angular position is presented. Optimization of the control program is carried out by using a combined indicator that combines a quadratic performance criterion and turn time; the minimized functional combines energy costs and maneuver duration in a given proportion. Based on the maximum principle, quaternion models, and methods for studying the controlled motion of a solid (spacecraft), a solution of the problem has been obtained. The construction of the optimal rotation is based on a differential equation relating the angular momentum and the orientation quaternion of a solid. The conditions of optimality are written in analytical form and the properties of the optimal motion are studied. Analytical equations and calculation formulas for finding the optimal control are presented. The control law is formulated as an explicit dependence of the control variables on the phase coordinates. Key relations that determine the optimal values of the parameters of the angular momentum control algorithm are given. In the case of a dynamically symmetric body, a complete solution of the turn problem in a closed form is obtained: analytical dependences as explicit functions of time for control variables and relations for calculating the parameters of the control law are given. A numerical example and the results of numeric simulation of the rotation of a spacecraft as a solid under optimal control that demonstrate the practical feasibility of the proposed control method are given.