Kinetics, Hydrodynamics and Stochastodynamics of Cellular Structure Coarsening

For the first time the phenomenon of cellular structure coarsening are consistently analysed from the positions of kinetic, hydrodynamic and stochastodynamic theories of nonequilibrium statistical systems. Thereby micro-, meso- and macroscopic levels of approach are distinguished. At the microscopic level the cellular structure is describe by a probability distribution function in a phase space of cell coordinates and of cell sizes. A kinetic equation for the function is written and a development to a hydrodynamic equation of a mesoscopic cell medium is realised. It has the form of a diffusion-reaction equation with a negative "diffusion" coefficient and with a cell interface density playing the role of concentration. Its analysis reveals a new effect of macroscopic patterning in the cell medium: existence of space-correlated stochastic fluctuations of the cell interface density.Comment: 12 pages, Latex, 3 eps figures. Submitted for publication in Modern Physics Letters B on 11/04/97, accepted on 18/09/97 . Revision was made to include the PS figures in the body of the pape

On a family of integrable systems on S2S^2 with a cubic integral of motion

We discuss a family of integrable systems on the sphere $S^2$ with an additional integral of third order in momenta. This family contains the Coryachev-Chaplygin top, the Goryachev system, the system recently discovered by Dullin and Matveev and two new integrable systems. On the non-physical sphere with zero radius all these systems are isomorphic to each other.Comment: LaTeX, 8 page

Extremely Low Loss Phonon-Trapping Cryogenic Acoustic Cavities for Future Physical Experiments

Low loss Bulk Acoustic Wave devices are considered from the point of view of the solid state approach as phonon-confining cavities. We demonstrate effective design of such acoustic cavities with phonon-trapping techniques exhibiting extremely high quality factors for trapped longitudinally-polarized phonons of various wavelengths. Quality factors of observed modes exceed 1 billion, with a maximum $Q$-factor of 8 billion and $Q\times f$ product of $1.6\cdot10^{18}$ at liquid helium temperatures. Such high sensitivities allow analysis of intrinsic material losses in resonant phonon systems. Various mechanisms of phonon losses are discussed and estimated

Radiation transfer in dispersion medium in separating

The influence of a degree of separating dispersion medium layer on radiation balance regarding its optical dimensions, scattering phase function shape and albedo of single scattering was investigated. It was stated that the bleaching effect occurring at dispersion medium separating has certain space boundaries. The classical concept of the «infinitely extended dispersion medium» was clarifie

Influence of space limited of the dispersion medium on image quality characteristics

Influence of space limited of the dispersion medium on radiation distribution and the quality characteristic of image obtained through dispersing medium of the finite sizes is investigated. The way of calculation of boundary function and contrast function of a light strip is determined. It is shown, that space limited of the dispersion medium and illumination conditions render significant influence on image quality -characteristics