Vol 19, No 1 (2016)
- Year: 2016
- Articles: 12
- URL: https://journals.ssau.ru/pwp/issue/view/379
Articles
Six-wave radiation converter on thermal nonlinearity in the scheme with codirectional pumping waves
Abstract
The spatial selectivity of six-wave radiation converter on thermal nonlinearity in the scheme with codirectional pumping waves has been investigated at nonstationary regime and stationary regime. The influence of thickness of a nonlinear medium, angle of incidence of pumping waves and wave numbers of pumping waves on the bandwidth of spatial frequencies of six-wave converter has been analyzed. The comparison of the spatial selectivity between four-wave radiation converter and six-wave radiation converter has been made.
6-11
12-15
16-19
The method longitudinal sections for the calculation the own waves of shielded waveguides with a complex form of cross-section
Abstract
The method which can be used for calculation of own waves shielded waveguides with any law of change of parameters of a waveguide from cross-section co-ordinate is offered. The homogeneous system of linear algebraic equations to which the decision of a considered problem is reduced is received. Method approbation on an example partially filled shielded waveguides is spent.
20-26
Surface spin waves in spatially inhomogeneous films ferrospinels
Abstract
Considered are the peculiarities in the amplitude - frequency characteristics of the type layout of the delay line in Ref magnetized films of manganese and magnesium-manganese ferrospinels. Calculated wave number, phase and group velocities, attenuation coefficients of magnetostatic waves. The overall effect observed for films of ferrospinels is «oscillations in the transmission» in the frequency response of the magnetostatic waves with changing frequency. Changes in frequency response associated with the effects of resonant interaction of dipole and exchange waves. It is shown that the depth and the number of exchange minimums in the quartermaster films of different composition depends on the magnitude of the exchange interaction, surface anisotropy constants and parameters of the spin pinning at the free surface and interlayer boundary.
27-33
Optimization of routes of the movement of mobile measuring instruments of time of arrival of pulse signals at an assessment of coordinates of their sources
Abstract
Mean square errors of a fixing of pulse sources of a radio emission by repeated estimates of their angular provisions in various points of space on the basis of measurements of time of arrival of signals in spatially the carried positions are investigated. It optimization of routes of the movement of mobile measuring instruments in structure of on-off system for ensuring the best accuracy of finding of coordinates of radiators is executed.
34-39
Finite-difference model of the fractional oscillator of Van der Pol
Abstract
The algorithm of numerical modeling of self-oscillating system, defined by the equation of motion with fractional order derivative is offered. To discretize in time the equation of motion method is used the invariance of impulse response of linear resonators in combination with the formulas of the fractional differential transforms of discrete harmonic functions. The example of modeling of process of establishing self-oscillations in the fractional oscillator is given. Discusses the transformation of the finite-difference computational algorithm in the object of nonlinear dynamics in discrete time. Are provided spectral and correlation characteristics of chaotic self-oscillations of the fractional oscillator of Van der Pol in discrete time.
40-44
Characteristic of wingtip vortices formed around the hypersonic vehicle in the mesosphere
Abstract
One of the research areas in the physics of ionized gases is studying perturbations in supersonic vehicle around medium in the mesosphere of the Earth, that is necessary for studying problem of creation of a reliable radio link. This paper studies mechanism of radio transparency of the perturbed medium modeling as a collision ionized gas and its plasma state.
45-52
53-58
Application of Higuchi method to automatical determining epileptiform activity at the polysomnography
Abstract
This article explores the use of Higuchi’s fractal method to the analysis of the electroencephalogram, filmed during sleep in patients with diagnosed epilepsy. It is shown that the method is sensitive to the presence of epileptiform activity. To test the method used electroencephalogram, in addition to containing sites with epileptiform activity characteristic for different types of attacks, regions with different stages of sleep and artifacts of various origins. According to the results of applying the method to the analysis of the electroencephalogram Higuchi can be concluded about the possibility of creation on the basis of the computer-aided identification of sections with epileptiform activity to follow-up diagnostic conclusions.
59-63
System of the electrocardiosignal analysis for determination of the conditions of drivers with the criterion of «wakefulness-dream-exhaustion»
Abstract
The article discusses the development and implementation of a portable analyzer arrhythmias, electrocardiographic signal analysis technique for the presence of arrhythmias. The block diagram of the algorithm realizing the technique of the analysis arrhythmias is developed and presented. Filters for decrease of a noise level in a signal are offered. For these filters are chosen and resulted theirs types and characteristics.
64-67
Some genetic features of population migration
Abstract
The differential equation for moving genome of panmictic populations which has allowed find the dependence of speed of a population movement on various parameters, in particular the average time of generation alternation, area of the territory mastered by a population for certain time, length of a wave of the moving population is found. The differential equation for genome of the moving population with inbreeding is found that has allowed calculate the decrease in speed of the population movement depending on the inbreeding factor.
68-73
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