Yu.L. Klimontovich, S.A. Sukhin

An expression for the shock profile of a spectral line with allowance for nonelastic processes is obtained within the framework of the kinetic approach. The width and shift operator, corresponding to Stark broadening is governed by the behavior of the spectral density of low-frequency field fluctuations. Due to incorporation of the medium's polarization, the resultant expression does not contain a divergence corresponding to large impact parameters.

G.A. Bendrikov, V.I. Miftakhоv

The paper examines a graphical method for determining domains of stability with respect to a free parameter of systems described by the characteristic equations φ$_{n}$(p)+ ψK$_{m}$(p)=0. Unlike frequency methods, it employs simpler graphs on the real plane (ω $^{2}$, K). The method is advantageous for investigating the stability of higher-order and multicontour systems. Features of the application of the method to certain particular cases are examined. The results are illustrated by numerical examples. In the case of higher-order systems it is advantageous to perform the calculations by computer.

G.A. Bendrikov, G.A. Sidorova

Nonlinear automatic control systems, obeying the Popov criterion of unconditional stability of the equilibrium position in sector [0,k] are discussed. The root loci technique is used for obtaining conditions, in general form, at which this sector is at maximum and equal to the Gurvits sector of corresponding linear systems. Systems with class [3,m] and [4,m] linear parts are investigated.

V.G. Agakоv

The existence of an analytic solution of Einstein's equations, which contains a maximum number of physically arbitrary functions, in which scale factor R of the co-moving space passes through a regular minimum, corresponding to the finite density, is shown. Cases of an ideal and a viscous medium upon complete specification of the law of viscosity are considered separately. The nature of the distortion of the comoving space, variation in the volume and density of the ideal and viscous fluids are examined near the regular minimum of R.

N.V. Burbaeva

The problem of the density of states of deep fluctuation levels in a semiconduct or doped by fine donors and acceptors is considered with allowance for Debye screening. The dependence is found of the leading term of the logarithm of the density of states and of the electron localization radius 1/α on ionization energy E, for different values of parameter δ = N$_d$r$_{0}^{4}$/a$_{B}$, where N$_d$ is the donor population, r$_{0}$ is the screening radius, and a$_{B}$ is the Bohr radius of an isolated doping-material atom. It is clarified that the form of the distribution of doping-material electrons in an optimal fluctuation, the potential energy of an electron in an optimal well, and consequently, also the density of states of deep fluctuation levels are highly dependent on the screening radius r$_{0}$.

M.I. Zakharova, A.A. Aminоv

X-Ray diffraction analysis of mono- and polycrystals and electron microscopy are employed for investigating the structural mechanism and kinetics of precipitation of ω and α phases and ZrMo$_{2}$, Zr$_{3}$Al, and ZrV$_{2}$, intermetallic compounds from а β solid solution. It is found that an ordered ω$_{2}$ phase is precipitated from an ordered body centered cubic of the β solid solution in the Zr-Mo-Al alloy.

E.P. Efanova

Delocalizations of the A and С excitations of a mercury-like ion in the "bismuth" center of BaS-Bi phosphors at 80°K is investigated by considering the characteristics of a photostimulates scintillation. It is found that excitations in the A band are not accompanied by delocalization of impurity-electron excitations, whereas excitation in the С band is accompanied by delocalization involving "memorization" of the ionization location upon election breakoff.

V.S.Tsaplin, Yu.I.Logachev, E.L.Kondratyev

The need for performing the experiment described herein is justified. The correlation between the transmission spectrum of an aqueous solution at λ = 810 nm and the readings of the neutron monitor (correlation coefficient of 0.63) is found, which may serve as an indication of the relationship between phenomena occuring in the outer space and the structure of aqueous solutions.

Yu.V. Вerezin, A.N. Talitskу

The results of experimental studies of two-dimensional angular spectra of orthogonal projections of the vector of a partially scattered field, reflected from the F$_{2}$ ionosphere layer upon vertical sounding are presented. It is found that the center of the angular spectrum deviates from the undisturbed direction, the scattering of the wave along and across the terrestial magnetic field is anisometric, and also the degree of the scattering of orthogonal projections of the field differs.

Calibration of sound transducers in bounded volume

Nefedov N.N.

A method for calculating the directivity pattern of the far field of an emitter from the measurement of the pressure and its normal derivative in the near field of the emitter when the condition of free space is not satisfied, i.e., when the boundaries of a homogeneous acoustic domain affect the field produced by the emitter, is suggested.