IKBFU's Vestnik

2015 Issue №04

A Lax pair for the (1+3) nonlinear equation

Abstract

Integral systems with four independent variables have special signifi-cance in mathematics and physics. The discovery of inverse scattering method played an important role in reconsidering the place of integrable systems of nonlinear partial differential equations in mathematical sciences. The search for a systematic approach to developing exact solutions of such systems has become one of the main problems in the theory of integrable systems.

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Distribution of NQR relaxation times in the rotating frame of reference in micro-sized crystallites

Abstract

This article presents the results of an experimental study into the effect of powder crystallite size on spin-lattice relaxation times in a rotating frame for 35Cl NQR in potassium chlorate, as well as the nutation interferograms. To obtain the distribution of relaxation times, a multi-exponential decay inversion of the longitudinal component of the nuclear magnetization in a rotating frame was used. The multimodal nature of distributions is explained by the influence of surface irregularities and impurities.

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Enhancing the effectiveness of singlet-triplet energy transfer in a donor-acceptor pair of phosphor molecules under the influence of an external spin-orbit perturbation

Abstract

This article studies the effect of an extern heavy atom (KI salt) on the effi-ciency of nonradiative spin-forbidden singlet-triplet (S-T) transfer of elec-tronic energy between the rhodamine 6G (donor) and acriflavine (acceptor) dye molecules in polyvinyl alcohol films. The delayed fluorescence intensity enhancement and an increase in the lifetime of the acceptor triplet states in the presence of KI have been established. The constant rates of deactivation of the singlet and triplet states of dye molecules have been calculated.

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Features of the movement of a saline water final volume surrounded by fresh water on the bottom slope

Abstract

This article presents an experimental laboratory study of the movement of a finite volume of saline water (spots) surrounded by fresh and nonmoving water on the slope of the bottom in a non-rotating fluid. The findings include a quantitative assessment of the average rate of sliding of a saline water spot in fresh water along the slope of the bottom.

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On the procedure of calculating the electromagnetic field of a cable

Abstract

This article presents a method for approximate calculation of the compo-nents of an electromagnetic field produced by a cable system. This approach contributes to an efficient solution to the problem of electromagnetic compati-bility of radioelectronic equipment in a wide range of cable structure parame-ters.

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A comparative evaluation of the correlation analysis and maximum likelihood method resolution in the reception of phase-shift keying signals based on Barker codes

Abstract

This article presents the results of a MATLAB-assisted study into the maximum likelihood method resolution in the reception of two radioprobing signals based on Barker’s codes. The study is based on the expressions ob-tained by the authors within optimum reception theory that make it possible to carry out a joint evaluation of the same parameters of two signals and re-solve them based on these parameters.

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An analysis of processes of wall destruction in a test rig’s vacuum chamber

Abstract

This article presents the results of studies into the interaction between the walls of a test rig’s vacuum chamber and an SPD plasma jet. A method for calculating the spray elements of the vacuum chamber has been devised. The article presents the results of calculation of vacuum test chamber sputtering with an SPD-100 and SPD-100D plasma stream, as well as a way to protect the chamber’s walls from sputtering.

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The filtration radio pulse maximum likelihood method

Abstract

This article presents a solution to the problem of resolution of two radio impulses through the maximum likelihood method. The authors have obtained expressions for the optimum processing of a set of two radio impulses in the domains of their orthogonality and non-orthogonality, as well as expressions for the dispersion of radio impulse parameters (Rao-Cramér dispersion). The article presents the results of model calculations showing the possibilities of resolving two radio impulses using the maximum likelihood method. The au-thors assess the area of solution of the problem of resolving two radio impulses using the maximum likelihood method.

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The maximum likelihood method as applied to chirp signals

Abstract

This article presents signal processing through linear frequency modula-tion (chirp signals) using the maximum likelihood method. The authors have obtained main expressions describing the optimal algorithm for processing these signals, as well as expressions for chirp signal dispersion (Rao-Cramér dispersion). The article presents key findings of model calculations during the reception of chirp signals.

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A shortwave antenna module

Abstract

This article presents the methods to improve the weight and size charac-teristics of a universal transmitting shortwave radio antenna. The proposed version of a shortened antenna with a performance management system can significantly increase the radiation power provided the inductive element is of high quality and losses are minimal.

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