Diffraction of stationary cylindrical and plane sound waves by a cylinder in a viscous heat-conducting medium

The diffraction of cylindrical and plane stationary sound waves by a cylinder in a viscous heat-conducting medium is analyzed. A solution of this problem is given in [1] without regard for heat conduction.Tula. Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 3, pp. 147–154, May–June, 1972.     

Positron annihilation in Si and GaAs crystals with an applied magnetic field

The narrow components in angular correlation curves of positron annihilation in Si and GaAs were observed. Hence it follows the formation of positronium-like states in semiconductors. Effects of mechanical and radiation treatment of the samples of Ps-states are discussed.     

Qualitative and quantitative evaluation of the interface in activated shape memory alloy composites

The interfacial quality of shape memory alloy (SMA) composites was experimentally evaluated by differential scanning calorimetry, and quantitatively calculated using a combination of Šittner's model and a composite cylinder model. Results have shown that the damage level of the interface in a heating process can be quantitatively evaluated by measuring the transformation enthalpy of the subsequent heating cycle and comparing it with the S-shaped enthalpy kinetic curve. A combination of Šittner's model and a composite cylinder model is capable of calculating both the thermal behavior and the triaxial stress state of SMA composites.     

Spherical sound-wave diffraction by a sphere in a viscous medium

The problem of spherical sound-wave diffraction by a sphere in a viscous medium is discussed. Applying the method of separation of variables, we obtained exact formulas for the hydrodynamic field elements in a low-viscosity medium. Furthermore, by applying the Morse [1, 2] and Watson [3] method to the exact formulas, we determined asymptotic formulas for the same quantities in the case of long and shortwave propagation.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 133–146, January–February, 1973.     

Anomalous energy dependence of the electron relaxation time in bismuth

The relaxation time of highly nonequilibrium electrons whose excitation energy |Δε| is of the order of the Fermi energy ε _F is measured. The measurements are made on bismuth samples with the aid of transverse electron focusing with micron intercontact separations. The dependence of the electron collision frequency on the excitation energy is found to be close to linear. The possibility of observing the topological restructuring of a closed isoenergetic surface into an open surface in Bi with an increase in the electron energy is discussed. Pis’ma Zh. éksp. Teor. Fiz. 64, No. 12, 835–840 (25 December 1996)