An analytical expression has been obtained for the free energy of nonspherical molecnles systems in a solid-state approximation on the basis of an asymptotic expansion method. This expression makes it possible to identify thermodynamic characteristics, which are in good agreement with the experimental data for binary molecules and with the numerical experiment data within the limits of their accuracy.
Show AbstractThe parabolic correction method and the method of spectrum restriction with spectral band isolation are used to construct stable numerical algorithms for calculating waveguide systems of superhigh-frequency electrodynamics and of integral and fiber optics. Examples of numerical calculations have been given.
Show AbstractApproximate formulas for the drift velocity of a transition layer and for the lifetime of a nonstationary contrast structure in the problem of magnetic field generation in a turbulent medium have been derived.
Show AbstractA new exact solution of gravitation theory equations with a massive graviton has been obtained for the case when the source of a gravitational field is a plane electromagnetic wave.
Show AbstractIt is shown that in the kinematic range $Q^2\ge3$ GeV$^2/c^2$, $Q^2\gg k^2$, the main contribution into the cross section $d\sigma_T/d(k^2)$ of neutral pions electroproduction is made by the process of qnasielastic knocking-out of $\rho^0$- and $\omega$-mesons followed by their restructuring into a $\pi^0$-meson. It is proposed to use this property of electroproduction for directly probing the structure of the nucleon $\omega$-meson cloud, which will allow one to determine not only the momentum distribution of the $\omega$-meson in the nucleon, the spectroscopic factor of its separation, and the constant of $\omega NN$ interaction, but also the relative sign of the $G_{\rho NN}$ and $G_{\omega NN}$ constants.
Show AbstractChanges in dissipative properties of high-resistance CdS samples under the action of light and ultrasound are studied. Passage from darkness to light causes a jump change in the strain amplitude $\varepsilon^0$ in a standing ultrasonic wave and in the internal friction $Q^{-1}$ of the samples. Depending on the initial state, the response to illumination can be both positive (an increase in $\varepsilon^0$ and a decrease in $Q^{-1}$) and negative (a decrease in $\varepsilon^0$ and an increase in $Q^{-1}$). The action of ultrasound causes changes in $\varepsilon^0$ and $Q^{-1}$ jump values. The dissipative properties of CdS are discussed in relation to CdS cathodoluminescence spectra.
Show AbstractThe authors study a mathematical model of a distributed-parameter analog of a Van der Pol oscillator, which is a linear system of telegraph equations with nonlinearity in one of the boundary conditions. The theol-etical study reveals a buffer phenomenon, i.e., simultaneous existence of several stable periodic regimes in the boundary-value problem under investigation. The results of the experiment confirming the feasibility of this phenomenon are described.
Show AbstractThe formation of relativistic helical electron beams in flat and coaxial magnetic undulators with guiding magnetic field has been considered with due account for the undulator's edge fields. The feasibility of producing beams with low velocity spread has been demonstrated.
Show AbstractTheoretical calculations and results of experimental determination of the damping factor of a mechanical oscillator introduced by the coupled system of electric force action on the oscillator test mass have been presented. A possibility of regenerating the oscillations in such systems has been shown. The application of the results obtained to devices correcting the position of test masses in interferometric gravitational antennas has been discussed.
Show AbstractA new approximate method has been developed for calculating spectral coefficients of multilayer coatings with weakly nonhomogeneous layers. The method was demonstrated to be highly accurate. The most important feature of the method is the simplicity of parametric description of multilayer coatings with non.homogeneous layers, which is a decisive factor for further development of methods for synthesizing such coatings.
Show AbstractM$\stackrel{..}{o}$ssbauer studies of the (Tb$_{0,45}$Dy$_{0,55}$)$_{1-x}$Ho$_x$Fe$_2$ system have shown that spin reorientation occurred in the $(1\bar{1}0)$ plane in a narrow concentration range; the isotropic magnetic field on $^{57}$Fe nuclei depends linearly on the effective spin of the sublattice of rare-earth metal cations; and the anisotropic magnetic field included two contributions of the same sign and of the si;tme order of magnitude, those from localized magnetic moments and conduction electrons polarized by these moments. No changes in the hyperfine interaction parameters caused by spin reorientation were detected. Mechanisms of formation of electric field gradients in the vicinity of $^{57}$Fe nuclei in Laves phases of the RFe$_2$ type have been suggested.
Show AbstractEnergy exchange is illustrated in the wind-wave interaction system with the focus at the initial stage of generation of drift current and waves. Laboratory experiments helped determine the relation between the dynamic (friction) velocities of the wind flow and the drift current. It is shown that under the conditions discussed in this paper only 33 % of the momentum flux coming to the water mass from the atmosphere is expended on wave growth, while the remainder goes to the generation and evolution of the drift current. Energy balance components on the water surface have been computed for the initial phase of wind-wave interaction.
Show AbstractIt is shown that the interpretation of the geoelectric field as a result of baroelectric redistribution of charges in the Earth caused by tidal effects makes it possible to explain the difference in time dependence of the fair weather field over continents and oceans.
Show AbstractIt is shown. that when interpreting the effect of correlation between "gravitational" pulses and cosmic events, it is necessary to take into account the error associated with restoration of the original continual output signals of gravitational antennas assigned in digital form from the experimental data.
Show AbstractBased on the effective Lagrangian for the $b$-quark radiative decay process, the mass operator for a $b$-quark in a background non-Abelian chromomagnetic field has been considered. The imaginary part of the mass operator, which is proportional to the $b$-quark radiative decay rate, has been calculated in the one-loop approximation with due regard for the background field.
Show AbstractThe problem of effective positioning of temperature-sensitive elements for temperature control in powerful integrated circuits has been solved by the mathematical modeling method based on the computing-measuring systems.
Show AbstractA set of experiments has been proposed for model-independent evaluation of the amplitudes of autoionization state excitation by electron shock in atoms.
Show AbstractThe cases of pumping at a high $\omega_3$ and a low $\omega_2$ frequency have been studied. The properties of kink at the third harmonic frequency and of bright solitons at the first and second harmonic frequencies have been considered. The envelopes for high-frequency kinks at various relationships between the group velocities and the nonlinear distortion factors of the two three-frequency parametric interaction channels have been calculated by the numerical methods. The low-perturbation method describing the behavior of wave amplitudes at infinity has been suggested.
Show AbstractTheoretical models describing crossluminescence spectra in the tight-binding approximation, the free and localized core hole model in particular, are studied. For the latter model, one- and two-node localizations are considered. Changes in crossluminescence spectra determined by model parameter variations are analyzed.
Show AbstractA new speckle optics phenomenon has been experimentally discovered: local resonance amplification of ring-shaped edge laser speckles. The phenomenon is explained by the excitation and quenching of surface and edge plasmonpolaritons on the straight sharp edge of a blade in a laser beam.
Show AbstractThe dependences of basic characteristics of octahedral clusters on their atomic numbers have been studied theoretically for ten elementary and transition fee metals. Their similarity to the same dependences for crystals has been established. This similarity gives grounds to regard an octahedral cluster as an elementary structural unit of a crystal, which carries extremely important information about the nature of interatomic interactions in a crystal.
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