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Vol 59, No 7 (2016)

Plasma Physics

On the Features of X-Ray Emission of a Laser-Plasma Diode

Korobkin Y.V., Romanov I.V., Shikanov A.S.

Abstract

The formation of micropinches and X-ray sources in low-voltage, laser-induced discharges with high rates of current rise is investigated.

Russian Physics Journal. 2016;59(7):915-919
pages 915-919 views

Physics of Semiconductors and Dielectrics

Temperature and Field Dependences of Parameters of the Equivalent Circuit Elements of MIS Structures Based on MBE n-Hg0.775Cd0.225Te in the Strong Inversion Mode

Voitsekhovskii A.V., Nesmelov S.N., Dzyadukh S.M.

Abstract

A technique is proposed for the determining the parameters of the equivalent circuit elements in strong inversion mode using the measurement results of the admittance of MIS structures based on n-Hg0.775Cd0.225Te grown by molecular beam epitaxy. It is shown that at 77 K and frequencies above 10 kHz, the capacitancevoltage characteristics of MIS structures based on n-Hg0.775Cd0.225Te with a near-surface graded gap layer have a high-frequency behavior with respect to the recharge time of surface states located near the Fermi level of intrinsic semiconductor. It is established that the electron concentration in the near-surface graded-gap layer exceeds an average concentration found by the Hall method by more than 2 times. The proposed technique was used for determining the temperature dependences of the insulator capacitance, capacitance and differential resistance of the space-charge region, and capacitance of the inversion layer in MIS structures based on n-Hg0.775Cd0.225Te without a graded-gap layer. The temperature and voltage dependences of the parameters of the equivalent circuit elements in strong inversion are calculated. The results of calculation are qualitatively consistent with the results obtained from the measurements of the admittance.

Russian Physics Journal. 2016;59(7):920-933
pages 920-933 views

Article

Effect of a Short-Period InGaN/GaN Superlattice on the Efficiency of Blue LEDs at High Level of Optical Pumping

Prudaev I.A., Romanov I.S., Kopyev V.V., Brudnyi V.N., Marmalyuk A.A., Kureshov V.A., Sabitov D.R., Mazalov A.V.

Abstract

We present the results of experimental studies of internal quantum efficiency of photoluminescence of blue LED heterostructures based on multiple InxGa1–xN/GaN quantum wells with short-period InyGa1–yN/GaN superlattices containing small amounts of In at high levels of optical pumping. Introduction of an InyGa1–yN/GaN superlattice from the side of the n-region of a LED InxGa1–xN/GaN heterostructure allows to increase the value of its internal quantum efficiency presumably by reducing the quantum-confined Stark effect and Auger recombination rate.

Russian Physics Journal. 2016;59(7):934-937
pages 934-937 views

Relaxation Dynamics of Ferroelectric Liquid Crystals in Pulsed Electric Field

Kudreyko A.A., Migranov N.G., Migranova D.N.

Abstract

In this contribution we report a theoretical study of relaxation processes in surface-stabilized ferroelectric liquid crystals with spontaneous polarization. The influence of pulsed electric field on the behavior of ferroelectric liquid crystal in the SmC* phase, which is placed in a thin cell with strong anchoring of SmC* molecules with the boundary substrate, is studied. In the vicinity of the substrate interface, temporal dependence of the azimuthal motion of the director induced by electric field is obtained. The response to the external distortion of ferroelectric liquid crystal confined between two microstructured substrates is the occurrence of periodic temporal formation of solitons connected with the distortion of the director field n in the sample bulk. The interplay between microstructured substrates and director distribution of the ferroelectric SmC* phase is explained by the Frenkel–Kontorova model for a chain of atoms, but adapted for the continuum problem.

Russian Physics Journal. 2016;59(7):938-943
pages 938-943 views

Electrical Properties of Syntactic Foams Based on Hollow Carbon Microspheres and Polydimethylsiloxane

Chukhlanov V.Y., Selivanov O.G.

Abstract

The present research focuses on the effect that hollow carbon microspheres embedded into the polydimethylsiloxane elastomer have on the electroconductive properties of the composite material. The percolation point was experimentally determined. The dependence of electrical resistance of the syntactic foam on the content of semiconducting filler in the binder was revealed. The effect of the filler on the radarabsorbing properties was studied.

Russian Physics Journal. 2016;59(7):944-948
pages 944-948 views

Propagation of Ultrashort Electromagnetic Pulses in Dielectric with Two-Level Centers

Astapenko V.A., Manuilovich E.S.

Abstract

Special features of ultrashort electromagnetic pulse propagation in the two-level medium representing the glass matrix with active optical centers are theoretically investigated. Based on numerical modeling, peculiarities of evolution of the pulse waveform and change of the pulse spectrum depending on the propagation distance and pulse duration are revealed. Calculation was performed in the linear field approximation taking into account radiation dispersion in the matrix for pulses with corrected Gaussian envelope. The contribution of optically active centers to the dielectric permeability of the medium is considered in the two-level approximation.

Russian Physics Journal. 2016;59(7):949-955
pages 949-955 views

Impedance of Polymer-Dispersed Liquid Crystals with Carbon Nanofibers in Weak Electric Fields

Zhdanov K.R., Romanenko A.I., Zharkova G.M., Podyacheva O.Y.

Abstract

Impedance of polymer-dispersed liquid crystals modified by carbon nanofibers is studied in fields lower than the threshold field of the director reorientation of a liquid crystal. It is shown that the real and imaginary parts of the impedance obey to the relationship (Zre – X0)2 + (Zim – Y0)2 = R02, where X0, Y0, and R0 are the fitting parameters depending on the frequency of the exciting electric field.

Russian Physics Journal. 2016;59(7):956-960
pages 956-960 views

Structural State of a Weld Formed in Aluminum Alloy by Friction Stir Welding and Treated by Ultrasound

Klimenov V.A., Abzaev Y.A., Potekaev A.I., Vlasov V.A., Klopotov A.A., Zaitsev K.V., Chumaevskii A.V., Porobova S.A., Grinkevich L.S., Tazin I.D., Tazin D.I.

Abstract

The experimental data on structural state of an aluminum alloy, AlMg6, in the weld zone formed by friction stir welding are analyzed in order to evaluate the effect of its subsequent ultrasonic treatment. It is found that the crystal lattice transits into a low-stability state as a result of combined heat-induced and severe shear deformation. This transition is accompanied by considerable structural-phase changes that are manifested as an increased lattice parameter of the solid solution. This increase is caused by both high values of internal stresses and increased concentration of Mg atoms in the solid solution due to essential dissolution of the β-Al2Mg3 particles with the content of manganese higher than that in the matrix. This is accompanied by high-intensity diffusion and relaxation processes due to the low-stability state of crystal lattice (inhomogeneous stresses) in the weld zone.

Russian Physics Journal. 2016;59(7):971-977
pages 971-977 views

Investigation of Structure and Properties of Barrier Layers in Metals (Fe, Cu) at Low Temperatures

Kuterbekov K.A., Nurkenov S.A., Kislitsin S.B., Kuketayev T.A., Tussupbekova A.K.

Abstract

Experimental studies of the effect of a barrier layer on the kinetics of thermally induced diffusion procesess and phase transformations in a layered Fe–Be syatem are investigated at the energy ~1.6 MeV. Thermal stability of the barrier layer in the Fe:O+ system is validated and a possibility of its use as a subsurface layer for a beryllium coating is demonstrated. For the Cu:O+ system it is shown that the implanted layer in the matrix comes apart already at the annealing temperature ~180°C and could not be used in a copper matrix as a subsurface barrier layer. For the first time, a method is proposed for retardation of diffusion and phase formation processes and realized in a layered iron – beryllium system using an implanted layer of oxygen ions. The sequence and characteristic times of thermally-induced phase-transformation processes taking place in the subsurface layers and in the bulk of the Fe (10 μm) systems: O+ – Be (0.7 μm) – 57Fe (0.1 μm) and Fe (10 μm) – Be (0.7 μm) – 57Fe (0.1 μm) are determined.

Russian Physics Journal. 2016;59(7):978-983
pages 978-983 views

Quantum Effects at a Proton Relaxation at Low Temperatures

Kalytka V.A., Korovkin M.V.

Abstract

Quantum effects during migratory polarization in multi-well crystals (including multi-well silicates and crystalline hydrates) are investigated in a variable electric field at low temperatures by direct quantum-mechanical calculations. Based on analytical solution of the quantum Liouville kinetic equation in the linear approximation for the polarizing field, the non-stationary density matrix is calculated for an ensemble of non-interacting protons moving in the field of one-dimensional multi-well crystal potential relief of rectangular shape. An expression for the complex dielectric constant convenient for a comparison with experiment and calculation of relaxer parameters is derived using the nonequilibrium polarization density matrix. The density matrix apparatus can be used for analytical investigation of the quantum mechanism of spontaneous polarization of a ferroelectric material (KDP and DKDP).

Russian Physics Journal. 2016;59(7):994-1001
pages 994-1001 views

On the Formation of a Nutation Line Under Conditions of Magnetic Field Modulation

Davydov V.V., Dudkin V.I.

Abstract

A new technique describing the formation of a nutation line under conditions of modulation of the constant magnetic field B0 by a variable magnetic field is presented. Dependences of the nutation line profile (the number of peaks, their amplitudes, and widths) on the modulation field parameters and the magnetic field inhomogeneity ∆B0 in the zone of arrangement of the nutation coil are investigated. Results of experimental investigations are presented and their comparison with theory is performed.

Russian Physics Journal. 2016;59(7):1008-1015
pages 1008-1015 views

Resource Control for Physical Experiments in the Cramer–Lundberg Model

Nazarov A.A., Broner V.I.

Abstract

A Cramer–Lundberg mathematical model of a resource control system for physical experiments is considered. In the case when the amounts of demands for consumption of resources have an arbitrary distribution function B(x), an approximation of the solution of the Kolmogorov integrodifferential equation governing the probability distribution of amounts of a resource accumulated in a physical system is proposed. On the basis of a comparison with known exact results and results of simulation modeling, sufficiently high accuracy of the obtained approximation is demonstrated.

Russian Physics Journal. 2016;59(7):1024-1036
pages 1024-1036 views

Dynamic Properties of Adaptive Optical Systems

Lukin V.P., Sazonova P.V.

Abstract

Dynamic (temporal) characteristics of adaptive systems imaging through the turbulent atmosphere are analyzed. The Strehl parameter is analytically calculated on the basis of the generalized Huygens–Kirchhoff principle. The conventional adaptive system with finite frequency band (or finite response time) is described as a dynamic system with constant delay. It is shown that to provide efficient distortion correction in such adaptive system, the time delay must be much less than the transport time of the coherence radius, corresponding to the average wind velocity, through the optical beam. Adaptive optical systems in which correction phase is calculated using not only the signal, but also its derivatives are also considered. It is shown that such modernization of the control algorithm of correction for phase front distortions admits much greater time delays. The time gain compared to the system with constant delay is the higher, the stronger are phase distortions in the optical wave.

Russian Physics Journal. 2016;59(7):1052-1061
pages 1052-1061 views

Determination of Transformation Coefficients of the C2H4 Molecule

Fomchenko A.L., Belova A.S., Berezkin K.B., Ziatkova A.G.

Abstract

The object of theoretical research is the C2H4 molecule, as it is important to know its properties to address numerous problems of molecular physics. The “expanded” local mode approach developed earlier was used for a X2Y4 molecule. This approach makes it possible to obtain simple expressions for the transformation coefficients of the investigated molecule, which subsequently allows one to determine various spectroscopic parameters of the C2H4 molecule in a simple form.

Russian Physics Journal. 2016;59(7):1062-1070
pages 1062-1070 views

Influence of the Atmospheric Refraction on the Time Delay of Signals from Global Navigation Systems for Independent Navigation of High-Orbit Space Vehicles

Sharygin G.S., Meshcheryakov A.A., Korolev D.O.

Abstract

Excess delay time of signals from global navigation systems used for coordinate-time support of high-orbit space vehicles caused by the refraction during sliding radio-wave propagation in the Earth’s atmosphere is estimated. Conclusions obtained are compared with the data of experimental analysis of observable GPS signals.

Russian Physics Journal. 2016;59(7):1071-1075
pages 1071-1075 views

Interior Structure of Pinch Plasmoids in a GRT Gravitational-Electrodynamic Model

Bogdanovich B.Y., Nestorovich A.V., Sukhanova L.A., Khlestkov Y.A.

Abstract

The need to take the gravitational field (the curvature of spacetime) into account in a description of pinch plasmoids formed in high-voltage discharges in which super-high energy densities are reached is demonstrated. A description of the interior structure of such a plasmoid with the help of a new exact solution of the Einstein–Maxwell equations is presented. With the help of the developed model we have estimated the main parameters of such pinch plasmoids.

Russian Physics Journal. 2016;59(7):1090-1097
pages 1090-1097 views

Coherent X-Radiation Excited by a Beam of Multiply Scattered Relativistic Electrons in a Single Crystal in the Bragg Scattering Geometry

Blazhevich S.V., Noskov A.V., Nemtsev S.N.

Abstract

A dynamic theory of coherent x-radiation emitted by a divergent beam of relativistic electrons traversing a thin single-crystal plate is developed which takes into account multiple scattering of the electrons on the target atoms. The case is considered in which the target is quite thin, so that it is not necessary to take absorption of radiation into account, but the electron path in the target is quite long, so that it is necessary to take multiple scattering into account. Expressions are obtained which describe the spectral–angular characteristics of parametric x-radiation and diffracted transient radiation under these conditions. Conditions are described under which diffracted bremsstrahlung radiation can be neglected. The possibility of manifesting the effects of dynamic diffraction is investigated.

Russian Physics Journal. 2016;59(7):1098-1110
pages 1098-1110 views

Refractive Index of Highly Fluorinated α-fluoroacrylates in a Telecommunication Spectral Region Near 0.85 μm

Sokolov V.I., Akhmanov A.S., Igumnov S.M., Marusin N.V., Tyutyunov A.A., Khaidukov K.V., Buznik V.M.
Russian Physics Journal. 2016;59(7):1115-1117
pages 1115-1117 views

On The Question of an Analytical Calculation of Meson Masses

Rudnitskaya T.G., Musikhin A.Y.
Russian Physics Journal. 2016;59(7):1118-1119
pages 1118-1119 views

X-ray Phase Analysis and Electronic Structure of NdCaBiO and GdSrBiO Bismutites

Khuanbai E.K., Sal’keeva A.K., Syzdykov A.K., Bimbetova G.M., Kopbalina K.B., Khusan B.K.
Russian Physics Journal. 2016;59(7):1120-1122
pages 1120-1122 views

Condensed-State Physics

Discrete and Multifield Models of a Cosserat Chain: One-Period and Two-Period Solutions

Vasiliev A.A., Dmitriev S.V.

Abstract

A multifield theory of bodies with microstructure is developed. As the basic model we take the structural model of a Cosserat chain consisting of particles of rectangular shape. A linear complete discrete model, a linear reduced discrete model, and a nonlinear discrete model are derived and discussed. One-period and two-period solutions are obtained, describing small oscillations of particles in one direction and in different directions. Single-field and two-field, complete and reduced Cosserat models are constructed. It is shown that the singlefield model describes one-period solutions in the chain while the two-field model describes both long-wave one-period and short-wave two-period solutions.

Russian Physics Journal. 2016;59(7):961-970
pages 961-970 views

Quantum Electronics

Amplification of Conically Diverging Laser Beams in the Gas Amplifier of the THL-100 Laser System

Ivanov N.G., Ivanov M.V., Losev V.F., Yastremskii A.G.

Abstract

Amplification of conically diverging laser beams in the XeF(C-A) amplifier of the THL-100 hybrid laser system operating in the visible range (λ = 475 nm) is investigated experimentally and theoretically. Energies of 2 and 2.5 J are obtained experimentally and theoretically at the output from the XeF(C-A) amplifier for the chirped start pulse with energy of 0.8 mJ and duration of 2 ps. Patterns of changes of energy and spatial and temporal distribution of the amplified laser beam intensity are investigated theoretically. The maximal calculated energy density and the radiation pulse intensity are Wmax = 100 mJ/cm2 and Imax = 64 GW/cm2, respectively.

Russian Physics Journal. 2016;59(7):984-993
pages 984-993 views

Physics of Magnetic Phenomena

Effect of Pressure on Helical Ferromagnetism in MnSi

Povzner A.A., Volkov A.G., Yasyulevich I.A.

Abstract

Within the limits of the Hubbard model supplemented with allowance for relativistic antisymmetric Dzyaloshinskii–Moriya interaction, the spin fluctuation theory of helical band ferromagnetism is developed. The magnetic state equation is derived for the nonuniform order parameter together with expressions for the Néel temperature and the wave vector of a spin structure. The effect of pressure on the helical ferromagnetism is analyzed based on the LDA + U + SO calculations of the MnSi electronic structure at different pressures. It is shown that with increasing pressure, the effect of zero-spin fluctuations that reduce the Néel temperature is amplified, and at a pressure of 15.2 kb a quantum transition takes place accompanied by vanishing of the longrange magnetic order.

Russian Physics Journal. 2016;59(7):1002-1007
pages 1002-1007 views

Mathematical Processing of Physics Experimental Data

Probability of an Error in Estimation of States of a Modulated Synchronous Flow of Physical Events

Gortsev A.M., Sirotina M.N.

Abstract

A flow of physical events (photons, electrons, etc.) is considered. One of the mathematical models of such flows is a modulated synchronous doubly stochastic flow of events. Analytical results for conditional and unconditional probabilities of erroneous decision in optimal estimation of flow states upon the criterion of the a posteriori probability maximum are presented.

Russian Physics Journal. 2016;59(7):1016-1023
pages 1016-1023 views

Optics and Spectroscopy

Energy Spectrum and Optical Absorption Spectra of Fullerene C76 Isomers and Endohedral Metal Complexes on Their Basis Within the Limits of the Concept of a Strongly Correlated State

Lebedev Y.A., Lobanov B.V., Murzashev A.I.

Abstract

The energy spectra of five fullerene C76 isomers are calculated for the Hubbard model in the static fluctuation approximation. Based on the spectra obtained, the optical absorption spectra of pure fullerene C76 represented by the isomer of symmetry D2 and endohedral Lu2@C76, Sm@C76, and DySc2N@C76 metal complexes are calculated. The calculated optical absorption spectra agree qualitatively well with the available experimental data, thereby indicating a need to consider the strong Coulomb interactions in the study of the π-electron fullerene subsystem.

Russian Physics Journal. 2016;59(7):1037-1051
pages 1037-1051 views

Elementary Particle Physics and Field Theory

Single-Photon Emission of a Hydrogenlike Atom

Skobelev V.V.

Abstract

Implementing a previously obtained, original solution of the Dirac equation for an electron in the field of a nucleus (Ze) expressed in terms of the wave function of the corresponding Schrödinger equation and its derivatives in spherical coordinates and the spin projection operator Σ3 associated with the eigenfunction, taking into account in each component of the spinor the leading term of the expansion in the small parameter (Zα), α = e2 / ħc ≈ 1 / 137, the partial probabilities W of emission of a photon (Zα)* → (Zα) + γ have been calculated. Here two orthogonal states of the linear polarization of the photon, and also the spin states of the electron, which previously had not been taken into consideration, have been taken into account in the transverse gauge. It turns out that the probabilities W of emission of a photon per unit time for any allowed transitions are proportional to (Zα)4, as was previously accepted, and the selection rules for the quantum number m have the usual form ∆m = 0,±1. It was found that a spin flip does not take place during emission. In contrast to the customary situation with the selection rules for the quantum number l being of the form ∆l = ±1, for ∆m = ±1 there also exist integrals over dcosθ which are not equal to zero for undetermined odd values of ∆l. In this, and also in a fundamentally different dependence of the amplitude on the quantum numbers consist the differences from the traditional approach to the problem. Necessary conditions are formulated, under the fulfillment of which the selection rules for l are not changed, having values ∆l = ±1 for arbitrary ∆m, but it was not possible, however, to give a complete proof of these rules.

Russian Physics Journal. 2016;59(7):1076-1089
pages 1076-1089 views

Brief Communications

Modeling of Electronic Structure of a Monolayer Superlattice SiC/GeC

Basalaev Y.M., Kosobutskii A.V., Malysheva E.N.
Russian Physics Journal. 2016;59(7):1111-1114
pages 1111-1114 views