Calculation of Creep Strains of Thin-Walled Tubular Members Made of Linear Viscoelastic Materials Under Tension and Torsion

International Applied Mechanics - The problem of analysis of creep strains in thin-walled tubular elements made of linearly viscoelastic materials under uniaxial tension, pure torsion, and combined...     

On the energy transfer equation for weakly interacting waves

The derivation of the transfer equation based on analysis of the equations for spectral semi-invariant and not invoking equations for realization of the random wave field is presented. Uniformly valid asymptotic expansions for the third and the fourth spectral semi-invariant are constructed using the multiple scale method and the matched asymptotic expansion method. This approach makes it possible to investigate the boundary layer in a neighbourhood of the resonant surface where intensive growth in time of the third spectral semi-invariant occurs. This boundary layer defines the form of the transfer equations. An analogous boundary layer for the fourth spectral semiinvariant and its influence on the second and the third spectral semi-invariants are also investigated.     

Transamination of aminohydroxypyrimidines

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, p. 975, April, 1989.     

Detection of contrast objects inside biological media by near-field microwave diagnostics

Theoretical and experimental investigations demonstrate the prospects of near-field microwave location of malignant tumors in biological tissue. The theoretical analysis is performed in terms of the theory of near-field location developed for layered structures. The experimental verification of the theory is accomplished by sounding an aqueous medium with a controllable permittivity. The tumor contrast is calculated based on the ideas of the dielectric properties of healthy and affected human tissues. The reason for and the degree of background contrasts as applied to near-field measurements are studied experimentally. An optimal measuring scheme for minimizing the masking effect of background contrasts is proposed. The 2D images of a tumor-simulating contrast object immersed in the aqueous medium at different depths are obtained. The prospects of near-field diagnostics for subsurface temperature measurement are discussed.     

Radiative forces acting on point sources moving in a stratified fluid

Both components of the total radiative force acting on uniformly moving mass sources in a stratified incompressible fluid are calculated. These forces are related to the emission of internal gravity waves. One component of the radiative force is directed opposite to the direction of motion. This is the well-known wave drag force. Different useful representations of this component are derived for several typical point sources (monopole, dipole, and others). The other component, directed perpendicular to the direction of the motion, is calculated for the first time. The results obtained are extended to the case of rotating media, where internal inertial-gravity waves exist. Zh. éksp. Teor. Fiz. 112, 507–523 (August 1997)     

Superconducting resonator in strong microwave fields: Thermal domain, nonlinear thermal effects

The thermal nonlinearity of superconducting films in an electromagnetic field is investigated theoretically. It is shown that the transition of the superconductor from the superconducting to the normal state as a result of Joule heating exhibits hysteresis, corresponding to the onset of a bistable state in the film. It is shown that as a result of the nonuniformity of the amplitude of the electromagnetic field along the surface of the superconducting film, above some threshold a normal-phase domain forms in the superconductor. It is ascertained that the temporal evolution of the domain walls exhibits the character of thermal autowaves of heating or cooling. The nonlinear radio-frequency characteristics (reflection and transmission coefficients and frequency responses) of a stripline resonator under conditions of thermal nonlinearity are calculated. Zh. Tekh. Fiz. 67, 81–89 (October 1997)     

Bianchi surfaces in R3 and deformation of hyperelliptic curves

New solutions of the problem of describing hyperbolic surfaces of specified negative Gaussian curvature are obtained. The answer is given in terms of 9 functions.Translated from Matematicheskie Zametki, Vol. 52, No. 3, pp. 78–88, September, 1992.The first author (D. A. K.) wishes to express his appreciation to A. I. Bobenko for useful discussion.