Constructing a model transport equation for a massless bose gas and its analytic solution

A model kinetic equation is constructed for the transport of a massless Bose gas. This equation is applied to solve the boundary value problem for the transport of radiation in the half-space occupied by a dispersive medium that is in local thermal equilibrium with the radiation. It is shown that the difference in temperature between the dispersive medium and the incident radiation substantially depends on the character of the scattering properties of the particles in the medium. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 111, No. 3, pp. 462–472, June, 1997.     

Boundary Problems for the Quantum Bose Gas

A relaxation kinetic equation that describes the behavior of a Bose gas is derived. The Kramers half-space problem on isothermal slip is treated. An analytical solution and the number-of-particle distribution function for particles flying toward a wall, in explicit form, are obtained. The dependence of the slip velocity on the parameter that is the ratio of the chemical potential to the product of Boltzmann's constant by the absolute temperature is analyzed. The influence of the quantum effects on the isothermal slip coefficient is evaluated for He⁴.     

Poiseuille problem for an ellipsoidal-statistical equation and nearly specular boundary conditions

An analytical solution of the Poiseuille problem is obtained over a wide range of Knudsen numbers for the case when the tangential momentum accommodation coefficients of the channel walls are much less than unity. An expression for the mass flux is derived that is valid for Knudsen numbers much smaller than the reciprocal of the accommodation coefficients. A new intermediate flow regime, for which the mass flux is given by an expression that differs from the classical (macroscopic) form, is found to exist. Zh. Tekh. Fiz. 68, 27–31 (November 1998)     

The temperature jump and slow evaporation in molecular gases

We set up model transport equations that describe the behavior of molecular (diatomic and polyatomic) gases with a molecule collision rate proportional to the molecular velocity. In deriving these equations we allow for the internal (rotational) degrees of freedom, while the vibrational degrees of freedom are assumed “frozen.” We also set up an exact equation for the problem of the temperature jump with allowance for slow evaporation from the liquid surface into the saturated vapor atmosphere. Finally, we derive explicit formulas for calculating the coefficients of the temperature jump and gas-density jump above a flat surface and do the necessary numerical calculations. Zh. éksp. Teor. Fiz. 114, 956–971 (September 1998)     

Phospholipid and fatty acid compositions of the lipids of the eggs and caterpillars of the silkworm, and of artificial diets and their components

The lipids of silkworm eggs in the period of diapause and embryonic and postembryonic development, of artificial feeds, and of the main lipid-containing components of artificial nutrient media have been investigated.Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 192–197, March–April, 1994.     

New method for measuring the IR surface impedance of metals

A method for measuring the IR optical properties of metals, which implies the analysis of the angular distribution of the photons emitted from the edge of a metal plate due to the conversion of thermal surface plasmons, has been theoretically and experimentally shown. In this work an increased accuracy of the proposed method in the IR region is demonstrated in comparison with more conventional methods based on the Fresnel formulas. This conclusion is supported experimentally with data obtained from the surface impedance measurement of copper in the range from 8 to 9 μm at 185°C.     

Mesoscopic properties of quasi-one-dimensional conductors with a charge density wave

Recent experiments on a search for small-scale quantum coherence in quasi-one-dimensional materials with a charge-density wave are reviewed.     

Temperature dependence of Aharonov-Bohm oscillations in small quasi-ballistic interferometers

The temperature dependence of the Aharonov-Bohm oscillations of small quasi-ballistic ring interferometers (effective radius R = 90–110 nm) is studied in a wide temperature range of (0.34–9) K. It is found that this dependence is determined not only by the size of the interferometer, but also by its microscopic state. It is shown that the effect may be associated with the influence of the fluctuation potential leading to different, but not completely stochastic, realizations of the scattering potential in conducting channels of the ring.     

Calculation of the Slip Velocity of a Rarefied Gas on a Solid Spherical Surface with Allowance for Accommodation Coefficients

The slip velocity of a rarefied gas with inhomogeneous temperature and mass velocity on a solid spherical surface is calculated with the use of a twomoment boundary condition in the linear approximation in terms of the Knudsen number. The dependence of the slip velocity on accommodation coefficients of the two first moments of the distribution function is studied.