IKBFU's Vestnik

Physics, mathematics, and technology

Introduction

Theoretical physics

The dynamics of localized pulse as solutions of Davey — Stewartson II equations

Abstract

A class of spatially localized solutions of Davey — Stewartson II equation is examined; it is shown that such solutions tend to lose the locality properties with time scale corresponding to a characteristic space scale of initial localization. The locality loss manifests itself with emergence of resonance spikes, whose total number is determined by the asymptotic behavior of support function on infinity. In particular, the exponentially localized perturbations split into an infinite number of the resonances.

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Estimation of errors of detecting the condition of a u bitqubit

Abstract

In this paper we study the back-action of the quantum point contacton the state of a double quantum dot during the measurement process. To describe this action we introduce an auxiliary subsystem, which is in the entangled states with the original system. This model allowed us to estimate establishment of the steady state of the combined system «double quantum dot — quantum point contact», and identify it as a measurement time and estimate the errors of the qubit states detection.

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Theoretical research of working conditions of a chink without pollution near to sea coast

Abstract

On the basis of a method of the image of special points the hydrodynamic model of work of a water chink at sea coast in the presence of semicircular inclusion is received. For various cases working conditions of a chink without pollution are investigated.

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Radiophysics

Geometrical phase of NQR signals

Abstract

The non-cyclic geometric phase of nuclear quadrupole resonance (NQR) signals, which is induced by the trajectory of nuclear magnetization motion upon the external pulse r. f. excitation, was studied. Analytical expressions for the geometric phases of NQR signals were obtained for the case of nuclei with spin I = 3/2. The powder sample of KClO3 was served as a material for experimental part of studies reported. It was proposed an alternative variant of the nutation experiment, which allows one to obtain the asymmetry parameter η on the base of locations of frequency singularities in the nutation phase spectrum.

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About radio transmit system work control on radiation

Abstract

On the basis of the analysis of principles of antennas’ system work on radiation the way of their operative emergency definition taken as a principle the developed device is developed. Introduction of a quantitative estimation of transmit system efficacy, will allow to solve a problem of automatic radio stations᾿ control under influence of negative factors.

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Reseach of loses at propagation of the radio signal of cellular communication on the basis of statistical models

Abstract

Calculation of level of losses of a radio signal of cellular communication in the conditions of a city with dense many-storeyed building on the basis of statistical models is resulted. On the basis of statistical look-ahead estimations of loss of capacity of a signal on an input of user's stations scientific directions of perfection of parameters of cellular communication can be developed.

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About ordinary-unordinary pulse spreading under the synchronism conditions

Abstract

The nonlinear process dynamic during the signal spreading in the optical lines is considered. The analysis of analytical solves of the equation system that obtained by consistent iterations and stationary phases method show about the "mass center" of signal spectral density displacement to the frequency, that simultaneously satisfy to the phase and group synchronism conditions.

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Spectral characteristics of atmospheric disturbances at middle latitudes during geomagnetic storms

Abstract

The paper discusses the possibility of physical interpretation of the global ionosphere disturbances during geomagnetic storms, and after them, based on Poincare waves excited in the atmosphere under such conditions. The spectrum of the diurnal variations TEC perturbations were obtained for the midlatitude stations located in the European longitude sector. It is shown that in the spectrum of TEC variations are present harmonics with periods of the relevant standing planetary waves Poincare. Analysis of the latitudinal structure of amplitudes and periods of the harmonics shown a qualitative agreement with theoretical estimates for the Poincare waves.

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Magnetic resonance properties of Fe3Si/ MgO thin film structures

Abstract

The article presents anisotropic properties investigation of Fe3Si / MgO thin film structures with different growing conditions and Si content. Growing conditions and Si concentration parameters make an impact on shaping of induced magnetic crystalline anisotropy. Results of experiment data simulation allows to extract magnetic anisotropy constants, proved by known results for same structures.

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Improving the efficiency of wavelet signal processing of NQR signals with modified Morlet basis functions

Abstract

In this work it is shown that application of the modified function of Morle as basic function of wavelet-transformation has allowed α to achieve by a choice of optimum parameter increase in the permission of the non-stationary signals of magnetic resonance, essential localization separate a component of a multicomponent signal and to raise the accuracy of definition of spectral parameters strongly noisy signals.

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Search on a regime of processing of leaky wave antenna

Abstract

An expression for the radiated power through the slit of the constructed system leaky wave antenna is obtained. The equation of balance of power in the waveguide is evolved. The loss of the wave power from the waveguide through the slit is taken into account. To calculate the damping factor, the equation is obtained. The possibility of an approximate simplification of this equation is investigated.

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Employment of the method of equivalent circuits to investigate a leaky wave antenna

Abstract

The resistive-capacitive electric circuit is obtained to describe the processes of the wave transmission and of radiation in the antenna of leaky wave. The equivalent electric parameters of the circuit are estimated. The system of equations is composed to describe the electric processes in the equivalent circuit To study the balance of the wave power in the antenna of leaky wave, the calculations are performed.

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The applying of digital interferometric methods to nano-displacement registration

Abstract

The estimation of limiting sensitivity of digital holographic methods of measurements of a surface of movings is lead}. Influence of a degree of digitization of hardware on limiting the sensitivity of digital holographic measurements is analysed. Parameters of surface — acoustic waves with amplitudes of fluctuations less than 10 nanometers are experimentally investigated.

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Method of processing of the ionospheric signals pulse

Abstract

The new method of processing of pulse ionospheric signals is presented. It is based on positions of the theory of optimum reception. However these positions are applied to difference to the equation received after transformation of the accepted message. The theory of a method of processing is presented, the results of modeling calculations illustrating efficiency of a method of processing are resulted.

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Laboratory practicum

Mathematics

Numerical solution of the Schrödinger equations with polynomial potentials (Part I)

Abstract

The fundamental solution of a Cauchy problem and the spectral task for a one-dimensional Schrodinger equations with potential in the form of polynomials m P (x) (m  6) is solved. Numerical calculations are applied to modelling adiabatic potentials with two minima characteristic for a proton in compounds with intramolecular hydrogen bonds.

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Set of algorithms for constructing university timetable – part 1: system of evaluating timetable quality based on fuzzy logic and features of algorithm for searching an optimal timetable

Abstract

A new approach for evaluating the quality of University timetables is proposed. This approach uses a multicriterion expert system with two quality
indexes: the average penalty imposed on timetabling and highest penalty imposed on one of the constraints. The system based on a series of intelligible rules and use the algorithms of fuzzy logic for getting the final evaluation of timetabling was created. An algorithm for searching a set of Pareto optimal timetables based on the Pareto simulated annealing algorithm is constructed.

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