A crystal plasticity surface compatible with dislocation flow is examined. Ow ing to the presence of a finite number of dislocation types in the crystal, it is a polyhedron in stress-deviator space. The laws of plastic flow of the crys tal associated with piecewise-linear loading functions are written with consid eration of strain-hardening and viscosity. Features of strain-hardening and stress relaxation associated with the polyhedral nature of the plasticity sur face are investigated.
Show AbstractThe problem of determining the critical values ν_(cr) and ω_(cr) of torsional flutter is solved as a boundary-value problem for a distributed elastic system. The vibration modes of an inhomogeneous wing in flutter and a comparison of the values obtained with those given by the Bubnov-Galerkin method are presented.
Show AbstractВ работе исследуется влияние случайных ошибок наблюдений ИСЗ (фотографических или лазерных) на точность вычисления элементов орбиты и влияние случайных ошибок элементов орбиты на точность прогнозирования движения ИСЗ. Приводится метод линейной параметризации элементов орбиты, позволяющий уточнять эфемериды ИСЗ в случае, когда элементы орбиты известны с большой погрешностью. Анализируются результаты расчетов на ЭВМ, полученные согласно изложенной методике.
Show AbstractThe properties of an electron-hole plasma in an intrinsic semiconductor are considered at high nonequilibrium-carrier (electron and hole) concentrations. A variational method is used to determine the single-particle spectrum of the sys tem with allowance for the interaction. An expression is derived for the free energy of the system within the framework of the approach used, as well as expressions for the free energy per pair of condensate particles.
Show AbstractThe hydroacoustic problem of the wave field of a point source In a coastal wedge is solved. The paper presents a number of concrete results that will be useful in practical hydroacoustics.
Show AbstractThe ray-tracing equation is solved in the second approximation by the perturba tion method for a spherically layered linear model of the ionosphere. The angle-of-arrival fluctuations of the wave and the mean direction of its emer gence from the ionosphere are calculated for isometric Gaussian random inhomo geneities on the basis of this solution, and the results are analyzed with com parison to the results for a plane-stratified medium.
Show AbstractThe kinetic equations of the biochemical glycolysis reaction are investigated in the relaxation regime. It is shown that an isolated volume in which this reac tion takes place is the sensitive element of the active medium, while the volumes connected by diffusion constitute the active medium as a whole.
Show AbstractEquivalent linearization offers a method for approximate calculation of the amp litude of self-oscillations in a one-dimensional distributed system when genera tion is single-mode.
Show AbstractThe role of the surface in transformation of electromagnetic to acoustic energy is studied in normal metals in the absence of a constant magnetic field.
Show AbstractFinite-dimensional spinor representations of a 15-parameter conformal group are obtained. Discrete transformations on the spinor space are considered.
Show AbstractFeatures of fieldless carrier heating on intraband absorption of light are studied. The stationary nonequilibrium distribution function is found in explicit form and the fluctuation stability of the state that it describes is demonstrated.
Show AbstractThe presence and magnitude of an interaction force between ions in an incompletely ionized plasma via exchange of phonons present in the neutral gas are established. The distribution of the field of extrinsic and electrostatic forces within a con figuration of spherical syrrunetry is found on the basis of a nonlocal-statistical approach. The stability of the formation to the volume perturbations is demonstrated.
Show AbstractThe class of model systems of equilibrium statistical physics with positive inter action of the type Jj^+ and sources in the limit of the unbounded system is investi gated. It is shown that the interaction results in weakening of the sources. It is found that phase transitions of a certain type are absent in the model systems considered. The results are illustrated with reference to a concrete model.
Show AbstractSolution of the ray-tracing equation by the perturbation method for a plane stratified linear model of the ionosphere is considered. The first-approxima tion solution for isometric and anisometric Gaussian random inhomogeneities is used in a computer calculation of the second-order moments of the emergence direction of the wave leaving the ionosphere, and their functional relation to the average geomagnetic latitude and azimuth of the radio path is established.
Show AbstractThe oscillation spectrum of a self-excited oscillator with a "hard" limit cycle under nonresonant parametric or power input of a harmonic signal is calculated theoretically with certain simplifying assumptions. The variation of the spectrum in response to variation of the input frequency outside of multiple-locking bands is considered. It is shown that the locking mode is established in re sponse to multiple inputs only by drawing of the oscillator's frequency, without damping of the self-oscillations. An experiment performed in the radio-frequency band with input multiplicities n = 2 and n = 4 shows good qualitative agreement with the theoretical conclusions.
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