Dusty plasma system in the surface layer of the illuminated part of the moon

The dusty plasma system in the surface layer of the illuminated part of the Moon has been considered. The maximum height of the dust rise has been determined. It has been shown that a dead zone, where dust particles cannot rise over the surface of the Moon, is absent near a lunar latitude of 80°. The size and height distributions of dust have been determined.     

Impacts of fast meteoroids and the separation of dust particles from the surface of the Moon

The possibility of the separation of dust particles owing to impacts of micrometeoroids on the surface of the Moon has been discussed. It has been shown that this effect is significant and should be taken into account when determining the number of particles rising over the surface of the Moon at the formation of a plasma–dust system. The average number of regolith particles leaving the surface of the Moon owing to the impacts of fast meteoroids has been determined for various altitudes over the Moon. The size distribution function of particles leaving the surface of the Moon because of impacts of meteoroids has been determined. It has been shown that impacts of meteoroids constitute an important source of dust microparticles in the plasma–dust system over the surface of the Moon.     

On the determination of the volume fraction of the crystalline phase in amorphous-crystalline alloys

The possibility of determining volume fractions of crystalline and amorphous phases of partially crystalline alloys from X-ray diffraction data has been discussed. The crystallization of an amorphous microwire of the Fe_73.9B_13.2Si_10.9C₂ composition has been investigated. The crystallization leads to the formation of α-Fe and Fe(Si). An analysis has been made of the X-ray diffraction patterns recorded for a series of samples with different contents of the crystalline and amorphous phases. The angular range has been determined and the calibration graph has been constructed, which can be used to determine the volume fractions of the amorphous and crystalline components in amorphous-crystalline samples.     

Modeling the propagation of electromagnetic waves over the surface of the human body

The results of modeling and an experimental study of electromagnetic (EM) waves in microwave range propagating along the surface of the human body have been presented. The parameters of wave propagation, such as the attenuation and phase velocity, have also been investigated. The calculation of the propagation of EM waves by the numerical method FDTD (finite difference time domain), as well as the use of the analytical model of the propagation of the EM wave along flat and curved surfaces has been fulfilled. An experimental study on a human body has been conducted. It has been shown that creeping waves are slow and exhibit a noticeable dispersion, while the surface waves are dispersionless and propagate at the speed of light in free space. A comparison of the results of numerical simulation, analytical calculation, and experimental investigations at a frequency of 2.55 GHz has been carried out.     

Character of variation in the microhardness of the (0001) plane of Zn single crystals under the action of electrostatic field and the possible reason for this effect

The influence of electric potential on the microhardness of the crystallographic plane (0001) of zinc single crystals has been studied. It has been established that the microhardness decreases with an increase in the supplied potential and, at the value of 0.05 V, reaches saturation. The total decrease in the microhardness is 8%. It has been shown that the variation of the microhardness is statistically significant. The observed effect has been explained by a reduction in the surface energy density due to electrization of the surface. The reduction in the surface energy with allowance for the existing single layer of adsorbed water has been estimated.     

Features of the transition radiation of the electron in the vacuum ultraviolet range

The transition radiation (TR) of an electron in the vacuum ultraviolet range near the direction of total quantum reflection from the medium-vacuum interface has been investigated. The effect of a substantial increase (tens times) in the TR angular density has been predicted. The substantial dependence of lightness of this effect on the susceptibility of the dielectric target, the exit angle, and the energy of the emitting electron has been found.     

Numerical modeling of the motion of a torsion balance in the problem of measuring the Newtonian gravitational constant

The motion of a torsion balance with five degrees of freedom has been numerically simulated. It has been shown that the oscillations along the swing degrees of freedom are excited by the random noise of the seismic origin and their amplitude varies with time. It has been shown also that the nonlinear couplings between the swing and torsion degrees of freedom result in the appearance of combination oscillations. The methods for effectively suppressing these combination oscillations have been considered.     

贵金属Au冷却过程中结构及能量变化的分子动力学计算机模拟

通过分子动力学方法,研究了不同冷速下贵金属Ａｕ在温度２０００～３００Ｋ的冷却过程中微观结构的变化特点,结果发现,冷却速度对Ａｕ的微观结构产生重要影响,采用偶关联函数和键对分析技术对原子局域团簇结果者分析,并考察了冷却过程中原子势能随温度的变化,比较了Ａｕ的微观结构转变与能量变化的对应关系,从能量转化的角度对冷却过程中Ａｕ的结构变化进行了说明。     

To the calculation of the composition of the multicomponent exciton gas

The nonequilibrium model of the exciton gas in semiconductors has been proposed. The composition of the multicomponent exciton gas has been calculated for Ge. The calculations based on the nonequilibrium model agree with the experimental data.     

Influence of the surface curvature of carbon nanotubes on their conductivity in the dirac approximation

A method of surface curvature of carbon nanotubes has been proposed for quantitative estimation of the longitudinal conductivity of nanotubes. A dispersion relation for the electron spectrum of single-walled carbon nanotubes has been obtained analytically. The change in the zone structure of nanotubes of various types and diameters caused by taking into account the surface curvature has been analyzed. The temperature dependence of the longitudinal component of conductivity with allowance for the surface curvature for a series of nanotubes has been calculated. The comparison with the conductivity of a plane graphene has been performed. It has been shown that, in zig-zag tubes, the correction of the conductivity for the surface curvature decreases with an increase in temperature as well as with an increase in the radius of curvature.     

Magnetic structure of the compensated ferromagnet-multiferroic interface

The magnetic structure of the compensated ferromagnet-multiferroic interface has been considered. The law governing the decrease of distortions of magnetic order parameters with increasing distance from the interface has been found. An expression for the energy of interlayer interaction of magnetic order parameters has been derived, and it has been shown that its magnitude is determined by the exchange interaction. The condition for magnetization switching of the ferromagnetic layer by an electric field applied to the multiferroic layer has been formulated. It has been demonstrated that the magnetoelectric effect and weak ferromagnetism are not prerequisites to the development of electric field-switchable magnetoresistive memory.     

Theoretical analysis of the operation of the kinetic inductance-based superconducting microwave detector

Nonequilibrium quasiparticle distribution functions that appear in a current-biased thin narrow diffuse superconducting strip under microwave irradiation at a low temperature have been calculated. A change in the kinetic inductance of the strip due to irradiation has been determined. The application of the strip as a microwave detector has been considered and the influence of the nonlinear phonon subsystem of the strip on the magnitude of the response has been found.     

Aspects of the crystal growth of the intergrowth tungsten bronzes

The crystal growth of a few of the members of the family of the rubidium intergrowth tungsten bronzes has been investigated as part of a program to study the compositionally induced metal to insulator transition in this bronze system. Progress in the study of this nonstoichiometric material has been made possible by successful growth of large single crystal samples. Application of vapor-assisted seeded crystal growth has led to an increase of the product crystal size by two orders of magnitude, from 0.1 mm on an edge to about 2 cm on an edge. Scanning electron microscopy has been used to characterize cracks, voids and intergrowths in this material. Transmission electron microscopy has been used to image the lattice of this quasi-two dimensional material in order to observe the frequency and amplitude of stacking defects.     

Theoretical Study into the Dichroism of the Absorption Bands in the IR Spectra of Oriented Polymers

The IR dichroism of the polarized absorption bands of oriented polymers has been considered. An equation has been obtained that makes it possible to calculate the dichroism of the absorption bands for a different degree of the polymer orientation. This equation has been simplified especially for structurally insensitive absorption bands. In this case it allows one to determine the type of polarization of absorption bands.     

Mean-field approximation for the potts model of a diluted magnet in the external field

The Potts model of a diluted magnet with an arbitrary number of states placed in the external field has been considered. Phase transitions of this model have been studied in the mean-field approximation, the dependence of the critical temperature on the external field and the density of magnetic atoms has been found, and the magnetic susceptibility has been calculated. An improved mean-field technique has been proposed, which provides more accurate account of the effects associated with nonmagnetic dilution. The influence of dilution on the first-order phase transition curve and the magnetization jump at the phase transition has been studied by this technique.     

Experimental investigation of the oscillator strength of the exciton transition in GaAs single quantum wells

A technique that makes it possible to investigate the mechanisms of phase relaxation of excitons in GaAs single quantum wells has been developed using resonant reflection spectroscopy. The dependence of the oscillator strength of the exciton transition on the quantum well thickness has been measured in the thickness range 9.1–30.0 nm. It has been demonstrated that the oscillator strength with a high accuracy does not depend on the temperature in the range 8–90 K. The temperature dependence of the homogeneous broadening has been measured, and the inhomogeneous broadening of the resonance exciton line has been determined. A nonmonotonic dependence of the spectral broadening of the exciton line on the intensity of the resonant excitation at a temperature of 8 K has been revealed for the sample with a high-quality quantum well. It has been established that an increase in the excitation level by five orders of magnitude above the linear limit leads to an insignificant change in the oscillator strength of the exciton transition and to a multiple broadening of the spectral line profile.     

Effect of the partial covalency on the solubility of AgBr In α-AgI

The internal energy and free energy of α-AgI-type solid solution have been calculated. On the basis of this calculation, the solubility limit of AgBr in α-AgI has been discussed. The difference of the solubility of AgBr in β-AgI and of β-AgI in AgBr has been interpreted due to the variation of the vibrational entropy depending on the mean value of anion mass. The partial ionicity in these solid solutions has also been discussed.     

Molecular-dynamics calculation of the thermal conductivity coefficient of the germanium single crystal

The thermal conductivity coefficient of the germanium crystal lattice has been calculated by molecular dynamics simulation. Calculations have been performed for both the perfect crystal lattice and the crystal lattice with defects such as monovacancies. For the perfect germanium single crystal, the dependence of the thermal conductivity coefficient on the lattice temperature has been obtained in the temperature range of 150–1000 K. The thermal conductivity coefficient of the germanium lattice has been calculated as a function of the monovacancy concentration.     

On the dependence of the lifetime of an atomic cluster on the intensity of its heat exchange with the environment

The molecular dynamics and Monte Carlo studies of the thermal stability of C₂₀, C₃₆, and C₆₀ fullerenes and the methane molecule are reported. It has been shown that the heat transfer between the atomic cluster and the external heat reservoir can either promote or prohibit the formation of defects in this cluster. The wide temperature and pressure ranges have been determined where the defect formation rate is essentially non-Arrhenius. It has been shown that the lifetime of light clusters in molecules depends more strongly on the contact with the heat reservoir. A statistical model that is based on the kinetic equation and allows for an analytical solution has been developed to explain the results. Within this model, the generalized Arrhenius formula has been derived to predict the lifetime of the clusters in an arbitrary thermal contact with the environment.     

On the inclusion of the statistical force in the Hamiltonian

An analogy-based technique of including the statistical force in the Hamiltonian has been proposed. Thermomagnetic current has been calculated using this technique. The method is suitable for calculations in both three-dimensional and low-dimensional samples.