Dynamic stability of a spiral domain in an ac magnetic field

The dependence of the stability of a magnetic spiral domain in a film on the parameters of the film and its domain structure and on an external magnetic field is considered within a phenomenological model. The model allows one to explain a number of experimentally observed properties of dynamic spiral domains resulting from the process of self-organization of domains and domain walls in an iron-garnet film placed in an external ac magnetic field.     

Semidomains and Metabelian Product of Metabelian Lie Algebras

This article is the fourth part of the series of papers whose aim is the construction of algebraic geometry over metabelian Lie algebras. __________ Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 14, Algebra, 2004.     

On characterization of Poisson and Jacobi structures

We characterize Poisson and Jacobi structures by means of complete lifts of the corresponding tensors: the lifts have to be related to canonical structures by morphisms of corresponding vector bundles. Similar results hold for generalized Poisson and Jacobi structures (canonical structures) associated with Lie algebroids and Jacobi algebroids.     

Load-Carrying Capacity of Circular Plates Made of a Fiber-Reinforced Composite

The load-carrying capacity of circular plates made of a fiber-reinforced composite and loaded with axisymmetric transverse forces under axisymmetric boundary conditions is investigated. The plates can be freely supported or clamped along their contour. To the known yield condition used, in the plane of main bending moments, there correspond irregular hexagons, which depend on the mechanical properties of composite constituents and some characteristic geometrical parameters. It is shown that, depending on the ratio of ultimate radial and circumferential bending moments, in the plastic state, the circular plates (the central part of the clamped plates) take the form of a cone or a frustum of cone. For each of the cases, the limit load is found, which is a function of the above-mentioned mechanical parameters. The statically allowable fields of bending moments and the corresponding allowable fields of deflection rates are determined. The solutions found are exact. Special cases for the freely supported plates are analyzed, and the results obtained are presented in the form of graphs.__________Translated from Mekhanika Kompozitnykh Materialov, Vol. 41, No. 2, pp. 177–192, March–April, 2005.     

A study of the mechanism and kinetics of interaction between nepheline powder and ammonium hydrofluoride

Behavior of a skeleton silicate, nepheline, in the reaction of fluorination with ammonium hydrofluoride was studied by means of differential-thermal, X-ray phase, and chemical analyses, IR spectroscopy, and scanning electron microscopy.     

Photon production in a dense medium

On the basis of diagram formalism for two-particle Green functions, the bremsstrahlung of charged particles interacting in a dense medium is investigated. In the case of production of soft photons, exact expressions for two-particle Green functions corresponding to the process of particle bremsstrahlung in the substance are obtained. The Green functions found are fully determined by the set of closed irreducible diagrams. It is shown that, in the case of radiation in a sufficiently dense medium in a far long-wave region of the spectrum, the coherent multiple particle scattering results in an additional (as compared that reported earlier in [1–13]) suppression of the bremsstrahlung photon yield.