Search

Your search keyword '"Petrov, Y. V."' showing total 18 results
Start Over Author "Petrov, Y. V." Language english
18 results on '"Petrov, Y. V."'

6. Spallative ablation of dielectrics by X-ray laser

Author

Inogamov, N. A., Zhakhovsky, V. V., Faenov, A. Y., Khokhlov, V. A., Shepelev, V. V., Skobelev, I. Y., Kato, Y., Tanaka, M., Pikuz, T. A., Kishimoto, M., Ishino, M., Nishikino, M., Fukuda, Y., Bulanov, S. V., Kawachi, T., Petrov, Y. V., Anisimov, S. I., and Fortov, V. E.

Published
2010
Full Text
View/download PDF

8. Temporal nature of plasticity in the design of materials

Author

Selyutina, N. S. and Petrov, Y. V.

Subjects
Finite element method, Plasticity -- Mathematical models, Plasticitat, Elements finits, Mètode dels, Matemàtiques i estadística::Anàlisi numèrica::Mètodes en elements finits [Àrees temàtiques de la UPC], Plasticitat -- Models matemàtics, Relaxation Model of Plasticity, Yield drop, Metals
Abstract

A full spectrum of materials responses to dynamic loading and observed temporal effects of plasticity from a united viewpoint are analyzed. The relaxation model of plasticity with characteristic time idea is capable to effectively predict the instability of the stress-strain dependencies on strain rates. It is shown that empirical models cannot simultaneously simulate the appearance and disappearance of the yield drop unlike the relaxation model of plasticity presented in the paper.

Published
2019

9. Doppler backscattering diagnostic with dual homodyne detection on the Globus-M compact spherical tokamak.

Author

Bulanin, V. V., Yashin, A. Y., Petrov, A. V., Gusev, V. K., Minaev, V. B., Patrov, M. I., Petrov, Y. V., Prisiazhniuk, D. V., and Varfolomeev, V. I.

Subjects
HOMODYNE detection, RAY tracing, TORUS, BACKSCATTERING, NEUTRAL beams
Abstract

This article considers a four-frequency microwave Doppler backscattering (DBS) system in the compact spherical tokamak Globus-M. The hardware was adequate for the purposes of studying the peripheral plasma in the tokamak. The multichannel DBS system is based on duplication of a dual homodyne detection circuit for four incident Ka-band frequencies. The ray tracing results for a spherical torus are described, and specific requirements for the antenna tilt adjustment are defined. Some new experimental results are given for using DBS diagnostics on the Globus-M tokamak in order to illustrate its efficiency. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

10. Control of the compression zone position in plasma streams generated by MPC

Author

Solyakov, D. G., Yuliia Volkova, Cherednychenko, T. M., Ladygina, M. S., Marchenko, A. K., Petrov, Y. V., Chebotarev, V. V., Makhlaj, V. A., Staltsov, V. V., and Yeliseyev, D. V.

Subjects
Динамика плазмы и взаимодействие плазма-стенка
Abstract

This paper is devoted to the investigation of magnetohydrodynamic characteristics of plasma streams generated by a magnetoplasma compressor (MPC) and control mechanisms of a compression zone position. Nitrogen, helium, and argon were used as working gases. The measurement results of electric currents spatial distributions in the plasma streams identified that for helium (P = 10 Torr) both toroidal vortices and magnetic field displacement from the near-axis region are observed, then, the electric current direction reverses. Similar spatial structure of the electric currents was observed for helium with the initial pressure of 2 Torr. However, in this case, the electric current direction changes much earlier. The electric currents flow from 20 cm to 30 cm from the central electrode of MPC accelerating channel in the modes with nitrogen (P = 0.6 and P = 0.3 Torr). There are current vortices and a sizable magnetic field displacement at a distance of a 6 cm to 18 cm from the MPC output. The duration of a plasma stream generation is about two times less for helium than for the modes of operation with other gases. Метою статті є дослідження магнітогідродинамічних характеристик плазмових потоків, що генеруються магнітоплазмовим компресором (МПК), та механізмів керування положенням зони компресії. У якості робочих газів було використано азот, аргон та гелій. Результати вимірювання просторового розподілу електричних струмів у плазмовому потоці продемонстрували, що для гелію (Р = 10 Торр) спостерігаються як тороїдальні вихори струму, так і витіснення магнітного поля із приосьової області, з подальшою зміною напрямку протікання струму. Подібну просторову структуру електричних струмів було отримано і для гелію з початковим тиском 2 Торр. Проте, у цьому випадку, напрямок протікання струму змінюється значно раніше. У режимах роботи з азотом на залишковому газі (P = 0.6 та P = 0.3 Toрр) струми розповсюджується на відстані від 20 см до 30 см від центрального електроду прискорювального каналу МПК. Розвиваються вихори струму із подальшим витісненням магнітного із приосьової області на відстані від 6 см до 18 см від виходу МПК. Також виявлено, що для режимів роботи з гелієм час генерації плазмового потоку майже у два рази менше, порівняно з режимами роботи на інших газах. Целью этой статьи является исследование магнитогидродинамических характеристик плазменных потоков, генерируемых магнитоплазменным компрессором (МПК), и механизмов управления положением зоны компрессии. В качестве рабочих газов использовались азот, аргон и гелий. Было обнаружено, что для гелия (Р = 10 Торр) наблюдаются как тороидальные токовые вихри, так и вытеснение магнитного поля из приосевой области, с дальнейшей сменой направления протекания тока. Подобная пространственная структура электрических токов была получена и для гелия с начальным давлением 2 Торр. Однако, в этом случае, направление протекания тока меняется значительно раньше. В режимах работы с азотом при остаточном давлении (Р = 0.6 и Р = 0.3 Торр) токи распространяются на расстояния от 20 см до 30 см от центрального электрода ускорительного канала МПК. Происходит развитие токовых вихрей, с дальнейшим вытеснением магнитного поля из приосевой области на расстоянии от 6 см до 18 см от выхода МПК. Также было установлено, что для режимов работы с гелием время генерации плазменного потока почти в два раза меньше, в сравнении с режимами работы на других газах.

Published
2018

11. Study of domain formation by ion beam in MgO doped lithium niobate single crystals covered by resist

Author

Vlasov, E. O., Chezganov, D. S., Gimadeeva, L. V., Neradovskiy, M. M., Akhmatkhanov, A. R., Chuvakova, M. A., Alikin, D. O., Kuznetsov, D. K., Petrov, Y. V., Mikhailovskii, V. Y., and Shur, V. Ya.

Abstract

The equipment of the Ural Center for Shared Use “Modern nanotechnology” UrFU and IRC Nanotechnology, Research Park of SPbU was used. The research was made possible in part by RFBR (15-32-21102-mol_a_ved), by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006) and by President of Russian Federation grant for young scientists (Contract 14.Y30.16.8441-МК).

Published
2016

12. Study of turbulence in the Globus-M tokamak plasma during the transition to the ELM-free H-mode.

Author

Yashin, A. Y., Bulanin, V. V., Petrov, A. V., Zhivulin, E. A., Gusev, V. K., Kurskiev, G. S., Minaev, V. B., Patrov, M. I., and Petrov, Y. V.

Subjects
TURBULENCE, PLASMA turbulence, BACKSCATTERING
Abstract

Here we report the results of the turbulence study in the high confinement mode (H-mode) with and without edge localized modes (ELMs). The study was performed by the Doppler backscattering (DBS) method on the Globus-M tokamak. It was demonstrated that the transition from the H-mode with ELMs to the ELM-free H-mode is characterized by the drop of the turbulence intensity near the periphery. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

13. Rarefaction after fast laser heating of a thin metal film on a glass mount.

Author

Inogamov, N. A., Khokhov, V. A., Petrov, Y. V., Zhakhovsky, V. V., Migdal, K. P., Ilnitsky, D. K., Hasegawa, N., Nishikino, M., Yamagiwa, M., Ishino, M., Kawachi, T., Faenov, A. Y., Pikuz, T. A., Baba, M., Minami, Y., and Suemoto, T.

Subjects
METALLIC films, DELAMINATION of composite materials, SURFACE tension, LASER heating, CHROMIUM
Abstract

Understanding the physics of laser-matter interactions in ultrashort pulses is important for many well-acknowledged applications from material modifications to biology. We numerically and experimentally consider the effect of sub-picosecond Ti:sapp laser actions on 60-100 nm gold films mounted onto a fused silica substrate. The pulse energy is sufficient to ablate the films. For the first time, we show that there are different regimes of ablation, and the formation of the 3D structures depends on the value of the absorbed fluence Fabs and the adhesion strength padh between the film and the substrate. Namely, a delamination threshold Fdelam and an ablation threshold Fabl (Fdelam < Fabl) exist if adhesion is weak. Above the lower threshold Fdelam, the whole film delaminates from the substrate. Above the higher threshold Fabl, the thin film ruptures near its middle plane. The external half of the film flies away, while the internal half remains on the glass substrate. There are two thresholds Fdelam and Fabl for the Au/glass and Ag/glass targets, because pure gold and silver are weakly coupled to the glass. The lower threshold Fdelam disappears in the case of a strong adhesion stress padh. Consequently, delamination as a whole becomes impossible. Although the rupture of a film remains because the ablation threshold Fabl is independent of on adhesion. Adhesion is high when an intermediate thin layer of chromium is placed between the gold and the glass. The film velocity after it separates from the substrate is low for the range of fluences Fdelam < F < Fabl because the acoustic impedance Zglass of glass is small relative to the impedance Zfilm of a gold film. Therefore, during an evolution, the absolute values (positive or negative) of the contact pressures are few times smaller than the absolute pressures in a gold film. However, above the ablation threshold Fabl < F, the velocity of the external part of a film becomes few times larger because the velocity is independent of the acoustic impedance of a substrate. These circumstances explain why 3D structures such as nanojet above the microbump appears in the case of a weak adhesion. The velocity should be not too large to allow to the surface tension and crystallization to stop an inflation and breakaway of a microbump. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

14. Thermal Effect in Dynamic Yielding and Fracture of Metals and Alloys.

Author

Gruzdkov, A. A., Sitnikova, E. V., Morozov, N. F., and Petrov, Y. V.

Subjects
THERMAL analysis, METAL fractures, METALLIC composites, EMBRITTLEMENT, WELDABILITY
Abstract

The explanation of transition between ductile and brittle modes of fracture based on the "incubation time" concept is proposed. This approach allows us to establish relation between the influences of different loading parameters (strain-rate, temperature) on the mode of fracture. Proposed criteria give explanation to anomalous behavior of yield limit and possible high-temperature embrittlement. [ABSTRACT FROM AUTHOR]

Published
2009
Full Text
View/download PDF

15. Structural macromechanics approach in dynamics of fracture.

Author

PETROV, Y. V., MOROZOV, N. F., and SMIRNOV, V. I.

Subjects
*FRACTURE mechanics, *STRENGTH of materials, *ELASTICITY
Abstract

ABSTRACT Discrete features of the dynamics of fracture of solids are analyzed. The problem of modeling of some of the specific effects of brittle fracture in the high loading rate conditions is discussed. An approach based on the system of fixed material constants describing macro-strength properties of the material is considered. New principles of material testing are analyzed. The corresponding incubation time criterion allows one to manage without the a priori given rate dependences of dynamic strength and fracture toughness. An application of the incubation time criterion to the problem of erosion is considered. [ABSTRACT FROM AUTHOR]

Published
2003
Full Text
View/download PDF

17. Laser-induced transformation of supramolecular complexes: approach to controlled formation of hybrid multi-yolk-shell Au-Ag@a-C:H nanostructures.

Author

Manshina, A. A., Grachova, E. V., Povolotskiy, A. V., Tunik, S. P., Povolotckaia, A. V., Petrov, Y. V., Koshevoy, I. O., Makarova, A. A., and Vyalikh, D. V.

Subjects
LASER-induced breakdown spectroscopy, SUPRAMOLECULAR chemistry, NANOSTRUCTURES, ORGANOMETALLIC compounds, DIELECTRIC materials
Abstract

In the present work an efficient approach of the controlled formation of hybrid Au-Ag-C nanostructures based on laser-induced transformation of organometallic supramolecular cluster compound is suggested. Herein the one-step process of the laser-induced synthesis of hybrid multi-yolk-shell Au-Ag@a-C:H nanoparticles which are bimetallic gold-silver subnanoclusters dispersed in nanospheres of amorphous hydrogenated a-C:H carbon is reported in details. It has been demonstrated that variation of the experimental parameters such as type of the organometallic precursor, solvent, deposition geometry and duration of laser irradiation allows directed control of nanoparticles' dimension and morphology. The mechanism of Au-Ag@a-C:H nanoparticles formation is suggested: the photo-excitation of the precursor molecule through metal-to-ligand charge transfer followed by rupture of metallophilic bonds, transformation of the cluster core including red-ox intramolecular reaction and aggregation of heterometallic species that results in the hybrid metal/carbon nanoparticles with multi-yolk-shell architecture formation. It has been found that the nanoparticles obtained can be efficiently used for the Surface-Enhanced Raman Spectroscopy label-free detection of human serum albumin in low concentration solution. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results