Concepts of possibility and necessity of an event, fuzzy one included, as well as concepts of integrating over possibllity and necessity have been considered.
Show AbstractА mathematical model for the process of activating immunocompetent cells has been proposed. An inverse proЬlem of identifying а model of an object based on the readings of the flowing cytometer has been posed and its correctness has been estaЫished. А mathematical experiment has been conducted.
Show AbstractThe effect of periodic inhomogeneity of а positive background on the dynamics of nonlinear potential waves in а cold plasma has been considered in а cuЬic approximation with respect to the field amplitude. Such an inhomogeneity results in splitting of the spectrum of the Langmuir wave into two branches, one of which appears to Ье damped. Medium inhomogeneity also results in а nonlinear frequency shift.
Show AbstractРассмотрен статистический механизм ускорения до релятивистских энергий протонов космических лучей. Найдено решение общего уравнения, описывающего процесс ускорения. Получен энергетический спектр протонов, соответствующий наблюдаемому.
Show AbstractCascade energy exchange between longitudinal alternating electric field of an open resonator and an electron beam passing through а series ofthin diaphragms with small apertures located in the resonator field, has been discussed. Formulas have been derived for the output velocity and electronic efficiency of а thin cluster. А mathematical and numerical model has been constructed for the description of this interaction in kinematic approximation with regard to the electron volume charge. Based on this model, estimates of the interaction efficiency and the admissible phase and velocity variations have been made. The possiЬility to reduce essentially the field strength required for efficient deceleration of the beam electrons has been demonstrated.
Show AbstractThe proЬlem of noncontact determination of thermophysical characteristics of а thin layer with the help of laser-induced thermal waves is theoretically studied. The finiteness of the laser beam diameter makes it possiЫe to find the thickness of the layer and its thermal diffusivity independently of one another. The authors analyze pulsed and continuous modes of thermal wave excitation and discuss the proЬlem of choice of optimal conditions for а particular sample under study.
Show AbstractThe present paper considers the possibility of using the spectrophotometric method for studying the thin films inhomogeneity. А hierarchic approach to the construction of mathematical models of investigation of thin films is put forward.
Show AbstractThe X-ray diffraction pattern of а sample of а Pd-Sm alloy has been studied. It has been experimentally found that, as а result of saturation with hydrogen at room temperature, а two-phase sample is turned into а single-phase state. The process has taken 10-15 days. The rate of diffusion of samarium atoms in the presence of hydrogen increased Ьу 4 or 5 orders of magnitude.
Show AbstractThe Shubnikov-de Haas effect, the quantum Hall effect and the electric transport properties of GaAs/Al$_x$Ga$_{1-x}$As heterojunctions have been studied, in which the Al$_x$Ga$_{1-x}$As layer is homogeneously doped with silicon and the GaAs layer is simultaneously 8-doped with different distances L5{200А<L5<1200А} from the 8-layer of the impurity to the heterojunction. The maximum concentration of 2D-electrons achieved is $1.1\cdot10^{13}$ см$^{-2}$ at $L_{\delta}=600 A$. Measurements have been carried out in the temperature range of 0.4<Т<300К in magnetic fields of up to 35Т bу analyzing the transverse magnetoresistance and the Hall effect, two-dimensional concentrations, transport and quantum mobilities of electrons in subbands of dimensional quantization at low temperatures have been determined. Electron mobilities in scattering on ionized impurities have been calculated for а multi-subband case.
Show AbstractThe paper concerns а theoretical study of the behavior of the extraordinary Nernst-Ettingshausen effect {ENEE} in magnetic granular alloys. Calculations have been made within the framework of the Zhang-Levi model. The authors consider an asymmetric scattering of spin-polarized electrons on impurities that occurs under the action of а spin-orЬital interaction. It has been shown that in granular alloys with surface scattering playing а significant part, the value of the ENEE coefficient $Q_s^b$ may Ье substantially higher than the ENEE coefficient $Q_s^b$ for а homogeneous ferromagnetic material; moreover, the coefficients $Q_s$ and $Q_s^b$ may have different signs.
Show AbstractPhysical modeling data are used for classifying intense convective humid-type vortices. It is shown that the criterion that determines the vortex structure in this class is Froude's thermal number Fr* =(ϑ_∞^2)/(Rg∆T/T_∞)
Show AbstractА theoretical model has been derived for nonlinear parametric interactions between seismic waves traveling in the geomedium. Formulas have been derived for particular calculations.
Show AbstractА canonical system of differential equations for а disturbed motion of the threebody stellar problem has been obtained. An analytical method of solution with consideration for the third and fourth order terms in the Hamiltonian of the problem has been developed. Secular parts of angular variables g1 and g2 in the arguments of cosines have been introduced as the new variables.
Show AbstractThe proЬlem of synthesizing а matched transducer between two coaxial waveguides of oval cross section shapes is studied. The proЬlem is analyzed in its full mathematical formulation, using two powerful methods, the finite difference method and the regularization method, for its solution. Numerical calculation data are given.
Show AbstractThe evolution of vibrations in two-dimensional cuЬic-nonlinearity gratings near the saddle point of the dispersion surface is analyzed. Using the first two evaluated integrals, а strict analytical solution of the coupled nonlinear differential equations for the excitation агеа widths descriЬing the processes of self-localization and delocalization in two mutually perpendicular directions has been oЬtained. The main features of space vibration dynamics have been identified as functions of the relation between the nonlinear and dispersion properties of the system.
Show AbstractThe relation between the delayed fluorescence (DF) thermograms and the thermoluminescence (TL) curves ofleaves ofhigher plants has been investigated. It is shown that the low-temperature peak. of the band А on the TL curve and the first peak in DF thermograms are of the same nature.
Show AbstractThe phenomenon of spatial quantization of edge laser speckles, directly observed а large distance apart from the diffraction edge, was found experimentally in diffraction of а Gaussian beam of laser radiation strongly contracted in the cross section at the straight sharpened edge of а semi-infinite metallic screen.
Show AbstractPulse propagation in vacuum is analyzed for the general case 0≤ω_0τ_0<∞ (where τ_0 is the pulse duration and ω_0 is the carrier frequency) taking into account the diffraction effects that are due to the finite extension of the wave beam carrying the pulse. The analysis is based on the exact analytical solution of the nonstationary parabolic equation oЬtained in this paper {in time-coordinate representation). The case of а Gaussian wave packet with frequency and wave chirps has been discussed in detail.
Show AbstractА theoretical model describlng the dynamics of channel shape and depth in punching holes Ьу а laser beam has been suggested. The model takes into account the principal characteristics of radiation absorption on channel walls.
Show AbstractAbsorption coefficient of longitudinal acoustic waves in polycrystalline titanium was measured in the temperature range from 120 to 220 К. Singularities of the Bordoni peak type related to energy dissipation Ьу point defects have been observed. Some quantities characterizing this absorption mechanism have been calculated.
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