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1,285 results on '"Sakharov, A V"'

234. Analysis of the Effect of Impurities on Primary Recrystallization in Pure Metals.

Author

Sakharov, N. V. and Chuvil'deev, V. N.

Abstract

A new model is proposed that describes the effect of impurities on the primary recrystallization in pure metals. In this model, the change in the temperature for the onset of recrystallization and the activation energy of the process is determined by the change in the relative free volume of the boundaries, which, in turn, is due to the presence of impurities at the boundaries. An equation is obtained that relates the recrystallization activation energy to the impurity concentration. It is shown that the recrystallization activation energy depends exponentially on the impurity concentration in grain boundaries. [ABSTRACT FROM AUTHOR]

Published
2022
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235. Influence of Voltage Polarity on Electric Strength of Thin-Film Capacitors.

Author

Sakharov, Yu. V. and Subbotina, A. E.

Subjects
*VOLTAGE, *SPACE charge, *ELECTRIC breakdown, *CAPACITORS, *BREAKDOWN voltage, *DIELECTRIC films
Abstract

The paper reveals the peculiarities of the influence of the polarity reversal of voltage applied to the plates of thin-film capacitors on the change in the electric breakdown voltage. The reason for the decrease in the voltage of the first breakdown of a thin-film capacitor is established when the polarity of the applied voltage is reversed. This decrease is due to a strong increase in the electric field strength in the bulk of the dielectric due to the accumulation of a negative space charge on the micro-tips of the electrodes when the electrode was at a negative potential. This effect is observed in Al-SiO2-Al and Al-TiO2-Al capacitor structures, which allows to assume its versatility and extend it to the entire spectrum of dielectric films used in microelectronics. [ABSTRACT FROM AUTHOR]

Published
2022
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236. Investigation of the Effect of a Small Addition of ZrO2 on the Density and Growth of Grains of Fine-Grained Aluminum Oxide.

Author

Boldin, M. S., Popov, A. A., Murashov, A. A., Sakharov, N. V., Shotin, S. V., Nokhrin, A. V., Chuvil'deev, V. N., Tabachkova, N. Yu., and Smetanina, K. E.

Subjects
ZIRCONIUM oxide, ACTIVATION energy, DENSITY, GRAIN size, POWDERS, GRAIN
Abstract

The effect of an additive of 0.5 wt % of zirconium oxide on the kinetics of electropulse plasma sintering (EPS) of submicron and micron α-Al2O3 powders. Al2O3–0.5% ZrO2 compositions were obtained by mixing Al2O3 powders in a planetary mill with grinding media from stabilized zirconium oxide. The activation energy of EPS was estimated using the Yang–Cutler model. It is shown that the density and average grain size in ceramics sintered from submicron Al2O3 powders are significantly affected by the nonequilibrium state of the interfaces formed as a result of the transformation of the amorphous phase present on the particle surface during EPS. The grain size and density of ceramics Al2O3–0.5% ZrO2, sintered from micron powders are significantly affected by the coalescence of ZrO2 particles. [ABSTRACT FROM AUTHOR]

Published
2022
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237. Investigation of the Microstructure of Fine-Grained YPO 4 :Gd Ceramics with Xenotime Structure after Xe Irradiation.

Author

Mikhaylov, Dmitriy A., Potanina, Ekaterina A., Nokhrin, Aleksey V., Orlova, Albina I., Yunin, Pavel A., Sakharov, Nikita V., Boldin, Maksim S., Belkin, Oleg A., Skuratov, Vladimir A., Issatov, Askar T., Chuvil'deev, Vladimir N., and Tabachkova, Nataliya Y.

Subjects
XENOTIME, CERAMICS, MICROSTRUCTURE, SINTERING, ANNEALING of metals
Abstract

This paper reports on the preparation of xenotime-structured ceramics using the Spark Plasma Sintering (SPS) method. Y0.95Gd0.05PO4 (YPO4:Gd) phosphates were obtained using the sol-gel method. The synthesized powders were nanodispersed and were agglomerated (the agglomerates sizes were 10–50 µm). The ceramics had a fine-grained microstructure and a high relative density (98.67 ± 0.18%). The total time of the SPS process was approximately 18 min. The sintered high-density YPO4:Gd ceramics with a xenotime structure were irradiated with 132Xe+26 ions with 167 MeV of energy and fluences in the range of 1 × 1012–3 × 1013 cm−2. Complete amorphization was not achieved even at the maximum fluence. The calculated value of the critical fluence was (9.2 ± 0.1) × 1014 cm−2. According to the results of grazing incidence X-ray diffraction (GIXRD), the volume fraction of the amorphous structure increased from 20 to 70% with increasing fluence from 1 × 1012 up to 3 × 1013 cm−2. The intensity of the 200 YPO4:Gd XRD peak reached ~80% of the initial intensity after recovery annealing (700 °C, 18 h). [ABSTRACT FROM AUTHOR]

Published
2022
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238. Spark Plasma Sintering of Al2O3–SiC Ceramics. Study of the Microstructure and Properties.

Author

Boldin, M. S., Popov, A. A., Murashov, A. A., Sakharov, N. V., Shotin, S. V., Nokhrin, A. V., Chuvil'deev, V. N., Smetanina, K. E., and Tabachkova, N. Yu.

Subjects
KIRKENDALL effect, CERAMICS, MICROSTRUCTURE, SINTERING
Abstract

The features of spark plasma sintering of submicron Al2O3 powders with different contents (0, 0.5, 1.5, 5 vol %) of β-SiC nanoparticles have been studied. The microstructure and hardness of Al2O3 + 5 vol % SiC ceramics obtained by sintering Al2O3 powders with β-SiC particles of various types (nanoparticles, submicron particles, fibers) have been studied. Sintering was carried out at heating rates Vh from 10 to 700°C/min. The sintering process of Al2O3–SiC ceramics with low heating rates (Vh = 10–50°C/min) has a complex three-stage character, with a flat area in the temperature range of 1200–1300°C. At high heating rates (Vh > 250°C/min), the usual three-stage character of sintering is observed. The analysis of temperature dependences of compaction was carried out using the Young–Cutler model. It was found that the kinetics of powder sintering is limited by the intensity of grain boundary diffusion. It is shown that the dependence of the hardness of Al2O3–SiC ceramics on Vh has a nonmonotonic character, with a maximum. In the case of pure alumina, an increase in Vh leads to a monotonic decrease in hardness. [ABSTRACT FROM AUTHOR]

Published
2022
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241. First Heat and Particles Transport Study in the Globus-M2 Spherical Tokamak with Neutral Beam Injection at the Current Ramp-Up

Author

Telnova, A. Yu., primary, Kurskiev, G. S., additional, Balachenkov, I. M., additional, Bakharev, N. N., additional, Gusev, V. K., additional, Zhil’tsov, N. S., additional, Kavin, A. A., additional, Kiselev, E. O., additional, Minaev, V. B., additional, Miroshnikov, I. V., additional, Patrov, M. I., additional, Petrov, Yu. V., additional, Sakharov, N. V., additional, Tokarev, V. A., additional, Tolstyakov, S. Yu., additional, Tukhmeneva, E. A., additional, Khromov, N. A., additional, Shulyat’ev, K. D., additional, and Shchegolev, P. B., additional

Published
2021
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246. Single-lobe single-wavelength lasing in ultrabroad-area vertical-cavity surface-emitting lasers based on the integrated filter concept

Author

Blokhin, Sergey A., Karachinsky, Leonid Ya., Novikov, Innokenty I., Gordeev, Nikita Yu., Sakharov, Alexey V., Maleev, Nikolai A., Kuzmenkov, Alexander G., Shernyakov, Yuri M., Maximov, Mikhail V., Kovsh, Alexey R., Mikhrin, Sergey S., Shchukin, Vitaly A., Ledentsov, Nikolai N., Ustinov, Victor M., and Birnberg, Dieter

Subjects
Lasers -- Analysis, Quantum electronics -- Research, Laser, Semiconductor device, Business, Computers, Electronics, Electronics and electrical industries
Abstract

Broad-area vertical-cavity surface-emitting lasers (AVCSELs) grown in the antiwaveguiding approach are examined. Results suggest that the conventional AVCSEL device lases in high-order excited modes.

Published
2008

250. Electron temperature measurements at the Globus-M2 tokamak using multi-laser Thomson scattering

Author

null Chernakov P. V., null Tolstyakov S. Yu, null Tkachenko E. E., null Solovey V. A., null Sakharov N. V., null Petrov Yu. V., null Mukhin E. E., null Makarov A. M., null Kornev A. F., null Koval A. N., null Zhiltsov N. S., and null Kurskiev G. S.

Abstract

Diagnostics of the plasma electron component by the method of Thomson scattering Te(R,t) of laser radiation makes it possible to reliably measure the spatial distributions of the electron temperature and density. One of the obstacles to the implementation of TS diagnostics in thermonuclear reactors is the distortion of the spectral characteristics of the optical system due to radiation-induced absorption and contamination of optical elements with erosion products of the first wall. As a consequence, the reliability of measurements by the TS method will decrease over time. The paper describes the method of multi-laser Thomson scattering, which will solve this problem. The results of the first experiments on the Globus-M2 tokamak are also presented. Keywords: plasma diagnostic, tokamak, thomson scattering, laser diagnostic, spectroscopy.

Published
2022

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