Low temperature transport in solid solutions of bismuth-antimony tellurides with arsenic, copper and tin
Low temperature transport in solid solutions of bismuth-antimony tellurides with arsenic, copper and tin
V. A. Kulbachinskii$^1$, A. S. Apreleva$^1$, V. G. Kytin$^1$, A. V. Koshelev$^1$
In this work, we have investigated the temperature dependences of the resistance $\rho$ (in the temperature range $4.2
Development of an electron linac for radiation therapy II Reducing the accelerating field strength, increasing the efficiency of the accelerating structure
Development of an electron linac for radiation therapy II Reducing the accelerating field strength, increasing the efficiency of the accelerating structure
D. S. Yurov$^{1,2}$, M. A. Borisov$^{2,3}$, A. S. Alimov$^{1,2}$, S. Z. Bagova$^4$, A. N. Ermakov$^{1,2}$, A. N. Kamanin$^{1,2}$, T. K. Lobzhanidze$^4$, N. I. Pakhomov$^{1,2}$, A. S. Simonov$^2$, V. V. Khankin$^{1,2}$, V. I. Shvedunov$^{1,2}$, I. V. Shvedunov$^2$, N. V. Shvedunov$^{1,2}$
The second part of the article on the development of a linear electron accelerator for the “Onyx” radiation therapy complex is devoted to solving problems associated with high electric field strength in the accelerating structure, which include high dark currents, a long training process, high pulsed RF power losses in the accelerating structure, its low efficiency. The article describes the steps we took to reduce the electric field and increase the efficiency of the accelerating structure. The main results of testing the bremsstrahlung characteristics for the final version of the accelerating structure are shown.
Show AbstractDevelopment of an electron linac for radiation therapy I Suppression of cathode back-bombardment effect
Development of an electron linac for radiation therapy I Suppression of cathode back-bombardment effect
D. S. Yurov$^{1,2}$, M. A. Borisov$^{2,3}$, A. S. Alimov$^{1,2}$, A. N. Ermakov$^{1,2}$, A. N. Kamanin$^{1,2}$, N. I. Pakhomov$^{1,2}$, A. S. Simonov$^2$, Y. Yu. Filippov$^4$, V. V. Khankin$^{1,2}$, V. I. Shvedunov$^{1,2}$, I. V. Shvedunov$^2$, N. V. Shvedunov$^{1,2}$
The article is devoted to the development of a linear electron accelerator for the radiation therapy complex “Onyx”. A brief overview of the accelerator is given, and the main problems that arose during the development process are indicated. The main part of the article contains a solution to the most critical of them, associated with the back bombardment of the electron gun cathode, which led to instability of the gun current and bremsstrahlung radiation dose rate over time. Changes in the design of the accelerating structure and electron gun are described, which made it possible to eliminate the problem of back-bombardment and achieve the required stability of bremsstrahlung parameters.
Show AbstractOptical diagnostics of fractal biostructures
Optical diagnostics of fractal biostructures
Yu. V. Ryzhikova, S. B. Ryzhikov
General approaches to solving the fundamental scientific problem associated with establishing quantitative relationships between the structural features of biomorphs and their spectral characteristics are considered. The scaling features of fractal biomorphs are determined based on theoretical analysis. The shape features of the Fourier spectra and their connection with the self-similarity elements of the illuminated biosystems are identified. The calculation of light diffraction on bioobjects indicates the possibility of using pattern and scaling analysis for their identification. The obtained modeling results make it possible to improve fractal methods of optical diagnostics of the analyzed biomorphs.
Show AbstractPrecession of stellar rings in the center of the Galaxy
Precession of stellar rings in the center of the Galaxy
B. P. Kondratyev, K. A. Klyuchinsky
The dynamics of two interacting concentric stellar rings located in the central parsec of the Galaxy is investigated. A massive wide ring with retrograde motion of stars (the "clockwise" disk) is modeled by a disk with a small cutout in the center. The other ring (the "counter-clockwise" disk) is represented by a thin circular ring inclined to the plane of the disk. The masses of the rings, their geometric parameters and spatial orientation are known from observa-tions. The mutual gravitational energy and torque between these rings are found, graphs of these quantities are constructed depending on the angle of inclination. The angular momenta of the rings and their ratio are calculated. The Laplace plane and the angles of its orientation are determined for the system of rings. It is established that mutual perturbation of the rotating rings leads to precession of the nodes with a period The lines of nodes of both rings in the Laplace plane move with the same angular velocity, but in opposite directions. This explains the large angle of divergence of the lines of nodes, known from observations.
Show AbstractTemperature changes in the mesopause region under climate changes in recent decades (1960−2024)
Temperature changes in the mesopause region under climate changes in recent decades (1960−2024)
I. I. Mokhov$^1$, V. I. Perminov$^2$, I. A. Fomina$^4$
The results of an analysis of temperature variations in the mesopause region based on long-term measurements of hydroxyl airglow at the Zvenigorod Scientific Station of the A.M. Obukhov Institute of Atmospheric Physics RAS (ZSS IAP RAS) in 1960–2024 in comparison with variations of surface temperature characterizing global-scale climate changes are presented. Along with temperature variations in the mesopause region, two versions of temperature variations in the mesopause region, normalized to the same level of solar activity, were analyzed. Quantitative estimates of a strong decrease of temperature in the mesopause region over the past decades in winter against the background of a global increase of surface temperature have been obtained. It was noted that significant coherence of long-term variations of the mesopause region temperature with the surface temperature in the Northern Hemisphere with the use of cross-wavelet analysis, which was not previously evident in data for a shorter time interval. The possibility of such coherence was predicted in (Mokhov et al., 2017) under the continuation of global warming based on the results of model simulations for the 20−21st centuries, taking into account anthropogenic forcing. It was not previously manifested from observational data for a shorter time interval. Along with long-term trends, features of a sharp decrease of temperature in the mesopause region for the 1970s with its synchronicity with the known shift in surface climate regimes associated with El Niño events were analyzed. The results of cross-wavelet analysis using data obtained at the ZSS IAP RAS for the time interval 1960−2024 indicate a more significant connection between temperature variations in the mesopause region and El Niño indices in recent decades.
Show Abstract{Features of the formation of β-carboxymethyl cyclodextrin complexes on the surface of lipid monolayers
{Features of the formation of β-carboxymethyl cyclodextrin complexes on the surface of lipid monolayers
I. V. Grigoryan$^1$, A. M. Adelyanov$^1$, G. B. Khomutov$^1$, A. P. Parkhaeva$^3$, E. Yu. Simonenko$^1$, A. G. Mironova$^5$, V. A. Pigareva$^2$, A. V. Sybachin$^2$
In this work, the interaction of β-carboxymethyl cyclodextrins (CMCD) with monomolecular layers of a mixture of electroneutral and cationic lipids on the surface of an aqueous subphase was studied.Monolayers were transferred to mica substrates using the Langmuir-Blodgett method and studied by atomic force microscopy. Analysis of monolayer compression isotherms and AFM images showed that CMC adsorption on the cationic Langmuir lipid monolayer is accompanied by the formation of supramolecular ensembles of similar morphology, regardless of the concentration of added oligosaccharides.
Show AbstractMolecular-dynamic simulation of structural transformations in the conducting channel of memristors based on nostichometric and ion-irradiated silicon oxides
Molecular-dynamic simulation of structural transformations in the conducting channel of memristors based on nostichometric and ion-irradiated silicon oxides
E. V. Okulich$^1$, V. I. Okulich$^2$, I. G. Kamilevich$^3$, D. I. Tetelbaum$^1$, A. N. Mikhaylov$^1$
The molecular dynamics method was used to simulate the processes of structural changes occurring over a time of about 100 ns in the region of the memristor filament formed in non-stoichiometric silicon oxides, including those subjected to ion implantation, during forming and/or switching. At the same time, the influence of the high temperature at which the filament region is located at certain stages of memristor operation was studied. It is shown that during the indicated periods of time, significant structural rearrangements occur, consisting in the formation and disintegration of various complexes, which is confirmed by calculations of radial distribution functions of distances between atoms in various combinations.
Show AbstractDynamics of Faraday rotation in hybrid magnetophotonic metasurfaces
Dynamics of Faraday rotation in hybrid magnetophotonic metasurfaces
A. M. Chernyak$^{1,2}$, A. I. Musorin$^{1,2}$, A. A. Fedyanin$^2$
The behavior of Faraday rotation on the femtosecond timescale in Mie-resonant magnetophotonic metasurfaces formed by a two-dimensional array of silicon nanodisks coated with a thin nickel film is studied. It is shown that in the static case the maximum of polarization plane rotation is 14◦ at the resonant wavelength for spectrally overlapped electric and magnetic dipole modes. When a single femtosecond laser pulse passes through the designed metasurface, it splits into two, the durations of which are half as long as the initial one, and the polarization planes are rotated in opposite directions, forming almost orthogonal replicas.
Show AbstractInfluence of annealing on magnetooptical properties of nanocrystalline films Fe$_{72.4}$Ti$_{5.4}$B$_{19.2}$O$_{3.0}$
Influence of annealing on magnetooptical properties of nanocrystalline films Fe$_{72.4}$Ti$_{5.4}$B$_{19.2}$O$_{3.0}$
N. N. Perova$^1$, E. A. Gan'shina$^1$, P. I. Mikhailovich$^1$, D. M. Gridin$^1$, E. V. Harin$^2$, V. A. Tejetov$^2$, E. N. Sheftel$^2$, A. B. Granovsky$^{1,3}$
The results of a study of the magnetic properties of Fe$_{72.4}$Ti$_{5.4}$B$_{19.2}$O$_{3.0}$ nanocrystalline films subjected to annealing in vacuum at 200°, 300° and 400°C are presented. Films with a mixed (nanocrystalline + amorphous) structure with a thickness of 0.52 μm were obtained by magnetron deposition on glass substrates. Hysteresis loops were measured on a vibrating magnetometer, field and spectral dependences of the transverse Kerr effect (TKE), and magnetization reversal processes were visualized on a magneto-optical Kerr magnetometer. It is shown that the processes of partial crystallization of the initially amorphous phase and the redistribution of Ti and B, respectively, within crystal grains and grain boundaries, resulting in the formation of new phases, which occur as a result of annealing, manifest themselves in a two-stage process of magnetization reversal and in modification of the TKE spectra.
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