All Russia Research Institute of Technical Physics

Moscow, Russia

All Russia Research Institute of Technical Physics

Moscow, Russia
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Kuropatenko V.,All Russia Research Institute of Technical Physics | Shestakovskaya E.,South Ural State University
CEUR Workshop Proceedings | Year: 2017

Mathematical modeling is now a key tool of research into dynamic processes in continuum mechanics. Each particular problem is solved with already existing or newly developed models and methods, whose properties are determined from a priori study into stability, approximation, monotonicity etc within linear approaches. The accuracy of difference schemes is mainly evaluated through comparison between calculated results and reference solutions. The paper discusses some problems which have analytical solutions. These are shock convergence, the dynamic compression of a gas sphere, and some problems with stationary shocks.


Kuropatenko V.F.,All Russia Research Institute of Technical Physics | Shestakovskaya E.S.,South Ural State University
AIP Conference Proceedings | Year: 2016

It is proposed the exact solution of the problem of a convergent shock wave and gas dynamic compression in a spherical vessel with an impermeable wall in Lagrangian coordinates. At the initial time the speed of cold ideal gas is equal to zero, and a negative velocity is set on boundary of the sphere. When t > t0 the shock wave spreads from this point into the gas. The boundary of the sphere will move under the certain law correlated with the motion of the shock wave. The trajectories of the gas particles in Lagrangian coordinates are straight lines. The equations determining the structure of the gas flow between the shock front and gas border have been found as a function of time and Lagrangian coordinate. The dependence of the entropy on the velocity of the shock wave has been found too. For Lagrangian coordinates the problem is first solved. It is fundamentally different from previously known formulations of the problem of the self-convergence of the self-similar shock wave to the center of symmetry and its reflection from the center, which was built up for the infinite area in Euler coordinates. © 2016 Author(s).


Lazarev Y.N.,All Russia Research Institute of Technical Physics | Syrtsova Yu.G.,All Russia Research Institute of Technical Physics
Journal of Experimental and Theoretical Physics | Year: 2012

An approximate analytic solution of Maxwell's equations is obtained inside a photodiode. Analysis of this solution shows that the earlier discovered significant decrease in the radiation field characteristics over an anode is caused by a considerable increase in the amplitude of a wave generated inside the photodiode, which for angles of incidence θ → π/2 achieves a value comparable to the initial electric field strength applied to the photodiode. In this case, the electromagnetic energy flux density inside the photodiode exceeds tens times or more the electromagnetic energy flux density over the anode. The results of numerical calculations confirm the analytic results. © Pleiades Publishing, Inc., 2012.


Zarakovsky G.M.,All Russia Research Institute of Technical Physics
Human Physiology | Year: 2014

The article is aimed at further developing V.I. Medvedev’s ideas about the specific character of human adaptation processes described in his monograph Adaptatsiya cheloveka (Human Adaptation) (St. Petersburg: Institute of the Human Brain of the Russian Academy of Sciences, 2003). The key point is the statement that “human adaptation is a process ensuring the attainment of a particular objective.” The article elucidates and develops this statement on the basis of a cross-disciplinary approach to the problem of adaptation (including biological, psychological, and social adaptation) and the results of a number of empirical researches. © 2014, Pleiades Publishing, Inc.


McGuffey C.,University of Michigan | Thomas A.G.R.,University of Michigan | Schumaker W.,University of Michigan | Matsuoka T.,University of Michigan | And 9 more authors.
Physical Review Letters | Year: 2010

Experimental studies of electrons produced in a laser wakefield accelerator indicate trapping initiated by ionization of target gas atoms. Targets composed of helium and controlled amounts of various gases were found to increase the beam charge by as much as an order of magnitude compared to pure helium at the same electron density and decrease the beam divergence from 5.1±1.0 to 2.9±0.8mrad. The measurements are supported by particle-in-cell modeling including ionization. This mechanism should allow generation of electron beams with lower emittance and higher charge than in preionized gas. © 2010 The American Physical Society.


Arapov Y.D.,All Russia Research Institute of Technical Physics | Dyakov V.A.,Moscow State University | Grechin S.G.,Moscow State Technical University | Kasyanov I.V.,All Russia Research Institute of Technical Physics
Laser Physics Letters | Year: 2014

The influence of the thermal deformation process on frequency conversion in an LBO crystal is considered. The different temperature bandwidths at the harmonic generation of YAG:Nd laser radiation were obtained experimentally three times at different types of crystal fixation. © 2014 Astro Ltd.


Pavlenko A.V.,All Russia Research Institute of Technical Physics | Balabin S.I.,All Russia Research Institute of Technical Physics | Kozelkov O.E.,All Russia Research Institute of Technical Physics | Kazakov D.N.,All Russia Research Institute of Technical Physics
Instruments and Experimental Techniques | Year: 2013

A one-stage light-gas gun with a 44-mm bore is described. If light gases are used, the gun ensures a 1.6-km/s limit impact velocity. The gun is used for studying the dynamic properties of structural materials, kinetics, and mechanisms of their destruction. The diameter of impactors and samples is 34 mm, and the angle skewness of the impactor surface relative to the target surface varies from 0.4 to 2.0 mrad. A brief description of the basic assemblies and measuring procedures of the light-gas gun is given. © 2013 Pleiades Publishing, Ltd.


Baidakov V.G.,RAS Institute of Thermal Physics | Tipeev A.O.,RAS Institute of Thermal Physics | Bobrov K.S.,RAS Institute of Thermal Physics | Ionov G.V.,All Russia Research Institute of Technical Physics
Journal of Chemical Physics | Year: 2010

We present the results of molecular dynamics simulations of the crystal nucleation rate in a supercooled Lennard-Jones liquid. The nucleation rate as a function of the pressure has been calculated by the method of determining the expectation time for liquid crystallization at temperatures higher than that of the triple point (T =0.865), close to the temperature of the terminal critical point of the metastable extension of the melting curve (T =0.55) and below this temperature (T =0.4). In computer experiments the nucleation rate varied from 1032 to 1035 s-1 m-3. The dimensions of critical nuclei and the pressure inside them, the surface free energy at a critical crystal nucleus-liquid interface, the height of the nucleation barrier, and the Zeldovich factor have been determined from the results of molecular dynamics simulations and their comparison with classical homogeneous nucleation theory. It is shown that the surface free energy at a curved crystal-liquid interface, as distinct from a flat interface, has also been determined at temperatures lower than the temperature of the terminal critical point of the melting curve and is a monotonically increasing function of the temperature. © 2010 American Institute of Physics.


Zav'yalov V.V.,All Russia Research Institute of Technical Physics
Atomic Energy | Year: 2015

The application of the Gauss–Seidel diagonal element isolation method is examined for obtaining an iterative solution of the system of thermal-radiation transfer equations for absorbing, radiating, and scattering media. Calculations of a test problem are preformed for the example of the correction form of the nonlinear variant of the method for the finite-difference WDD scheme in planar geometry. The method can also be used for modeling the transfer of γ-rays and neutrons. © 2014, Springer Science+Business Media New York.


Pavlenko A.V.,All Russia Research Institute of Technical Physics | Grigoriev A.N.,All Russia Research Institute of Technical Physics | Karnaukhov E.I.,All Russia Research Institute of Technical Physics
Technical Physics Letters | Year: 2014

Temporal waveforms of pressure amplitude in various regions of a flat electrically exploded foil (EEF) have been measured. The results of measurements have been used to reconstruct the temporal evolution of spatial pressure profiles generated by the EEF. The measurements were performed using quartz pressure sensors arranged in various (central and peripheral) regions of the free surface of a dielectric substrate glued to the foil. The obtained data show that the electric explosion starts at the edges of a foil, which is followed by stronger pressure buildup in the central axial region of the EEF. © 2014 Pleiades Publishing, Ltd.

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