Volga State University of Telecommunications and Informatics

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Samara, Russia
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Shevchenko A.P.,Samara University | Blatov I.A.,Volga State University of Telecommunications and Informatics | Kitaeva E.V.,Samara University | Blatov V.A.,Northwestern Polytechnical University
Crystal Growth and Design | Year: 2017

We propose three independent methods for determining geometrical shape and topological type of local atomic environment in crystals that is represented as a coordination figure. The methods are based on comparison of the edge graphs of the simplified Voronoi polyhedra, maximizing volume of intersection of polyhedra, and comparison of angular fingerprints of polyhedra. We implemented the methods to the program package ToposPro and tested them on 9642 crystal structures of five-coordinated copper and zinc complexes. The methods showed good selectivity and coincidence. We discuss correlations of the coordination figure type with other structure descriptors and perspectives to use the obtained results in knowledge databases. © 2016 American Chemical Society.


Burdin V.A.,Volga State University of Telecommunications and Informatics | Burdin A.V.,Volga State University of Telecommunications and Informatics | Dmitriev E.V.,Volga State University of Telecommunications and Informatics
Optics and Spectroscopy (English translation of Optika i Spektroskopiya) | Year: 2017

The necessary conditions for nonlinear excitation of higher-order modes in a single-mode step-index optical fiber are analyzed. The cutoff conditions for such an optical waveguide are investigated taking into account Kerr nonlinearity. The minimal power of optical pulses required for fulfilling the necessary conditions for nonlinear excitation of higher-order modes in a single-mode step-index fiber is calculated as a function of the normalized frequency. The allowed ranges of variation of the normalized frequency and optical-radiation power are estimated. It is demonstrated that the conditions necessary for nonlinear excitation of a higher-order mode in a step-index single-mode optical fiber can be created for optical pulses shorter than 500 fs. © 2017, Pleiades Publishing, Ltd.


Glushchenko A.G.,Volga State University of Telecommunications and Informatics | Glushchenko E.P.,Volga State University of Telecommunications and Informatics
Computer Optics | Year: 2017

In the article we show in the geometric approximation the possibility of slowing down the light propagating along the axis of an optical waveguide structure by using metamaterials as optical structure elements. We study features of light propagation using a plane model of a fiber optic line whose cladding material has a negative refractive index. It is shown that by introducing a metamaterial, the propagation of light waves in the structure can be changed so that the light is decelerated along the structure axis to the extent that it stops, before starting to propagate in the opposite direction. We derive relationships for calculating the delay time as a function of geometrical and optical parameters of the structure, relationships for calculating critical parameters, and conditions for stopping the light. © 2017, Institution of Russian Academy of Sciences. All rights reserved.


Dement'ev A.N.,Moscow Technological University | Klyuev D.S.,Volga State University of Telecommunications and Informatics | Shatrov S.A.,Progress Rocket Space Center
Journal of Communications Technology and Electronics | Year: 2017

A method for calculating the input impedance of a loop antenna (LA) located on a dielectric cylinder is developed. The integral equation (IE) for the unknown function of the current density distribution on the LA surface is obtained. A numerical method for the IE solution is described. An approximate formula for calculation of the LA input impedance is proposed. Plots of the input impedance on the LA length are given. © 2017, Pleiades Publishing, Inc.


Bourdine A.V.,Volga State University of Telecommunications and Informatics | Delmukhametov O.P.,Ufa State Aviation Technical University
Telecommunications and Radio Engineering (English translation of Elektrosvyaz and Radiotekhnika) | Year: 2013

A method for calculating the transmission parameters of random-order launched modes, propagating in telecommunication quartz multimode optical fibers with a random gradient profile of the refractive index, bounded by one external solid cladding, is presented. The solution is based on the use of the modified Gaussian approximation, generalized to the above case, in combination with the mixed finite element method, adapted for analysis of multimode fiber waveguides. Copyright © 2013 by Begell House, Inc.


Klyuev D.S.,Volga State University of Telecommunications and Informatics | Sokolova Y.V.,Volga State University of Telecommunications and Informatics
Journal of Communications Technology and Electronics | Year: 2015

A method for calculation of the characteristics of reflector antennas (RAs) is proposed. The method is based on the mathematical apparatus of 2D hypersingular integral equations. Radiation patterns of a RA with a reflector formed by a parabolic cylinder as well as distributions of the current density on the surfaces of the reflector and the feed calculated by this method are presented. © 2015, Pleiades Publishing, Inc.


Klyuev D.S.,Volga State University of Telecommunications and Informatics | Sokolova Y.V.,Volga State University of Telecommunications and Informatics
Journal of Communications Technology and Electronics | Year: 2015

A self-consistent method for calculation of the input impedance of a microstrip dipole (MSD) is proposed. A hypersingular integral equation (HSIE) for an unknown function of the distribution of the current density on the MSD surface is derived. A numerical method for calculation of the HSIE is described. Plots of the input impedance as a function of the dipole length and the substrate thickness are presented. © 2015, Pleiades Publishing, Inc.


Nikolaev B.I.,Volga State University of Telecommunications and Informatics | Chingaeva A.M.,Volga State University of Telecommunications and Informatics
WMSCI 2015 - 19th World Multi-Conference on Systemics, Cybernetics and Informatics, Proceedings | Year: 2015

In this paper we present a method for frame and timing synchronization in frequency selective fading channels. The method utilizes periodical structure of training sequences to build a differential frame "image", which is then used to find an exact training sequence position-hence the name of the method. The results of statistical simulation of the proposed method in ISI channel are also given and discussed.


Lozhkin L.D.,Volga State University of Telecommunications and Informatics
Journal of Communications Technology and Electronics | Year: 2013

It is shown that ambient illumination of the TV screen introduces color distortions in viewed TV programs. The magnitude and type of these distortions depend on the brightness and spectrum of the source of ambient illumination. A method for correction of these distortions is proposed and two ways of its implementation are considered. © 2013 Pleiades Publishing, Ltd.


Lozhkin L.D.,Volga State University of Telecommunications and Informatics
Journal of Optical Technology (A Translation of Opticheskii Zhurnal) | Year: 2012

This paper discusses the possibility of constructing an equal-contrast color space based on the mathematical apparatus used in Einstein's general theory of relativity. Such a construction makes it possible to avoid the drawbacks inherent to the color spaces that are currently known and used - namely, the difference of the sizes of the MacAdam ellipses, depending on the chromaticity of the stimulus. © 2012 Optical Society of America.

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