Effect of trapping centers of luminescent properties of bismuth orthogermanate

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 54, No. 6, pp. 970–975, June, 1991.     

Kinetic interpretation of the structural-time criterion for fracture

The incubation-period-based criterion for fracture is considered in terms of the Zhurkov kinetic model of fracture. Within the kinetic model, fracture is treated as a continuously developing process, which starts immediately after the application of a tensile load to a sample and consists in breaking of the interatomic bonds and gradual accumulation of broken bonds in the material in the course of a fracture test. For certain materials, the inclusion of the thermal-fluctuation mechanism for fracture in the incubation-period-based criterion significantly affects the position of the static branch of the time dependence of strength. Time dependences of strength are calculated for a number of materials. The experimental data are analyzed using the structural-time criterion for fracture, which allows one to obtain a unified time dependence of strength for quasi-static and high-rate short-term loadings. The temperature dependence of the incubation period (latent time) is calculated analytically, and a relation is found between the latent fracture time and the thermal vibration frequency of atoms.     

Magnetic Properties of Iron-Based Amorphous Metal Wires

It has been studied how the conditions of machining and the elastic tensile stresses affect the magnetic properties of amorphous metal wires of composition Fe₇₅Si₁₀B₁₅ produced by drawing from a melt. The magnetic characteristics of wires subjected to both thermal treatment and treatment with a continuous electric current of different magnitude have been investigated. The residual induction of wires is their magnetic parameter most sensitive to the conditions of treatment. The dependences of the residual induction on temperature and on the magnitude of the treating electric current are qualitatively similar. The greatest changes in residual induction are observed in the range of treating electric currents from 0.5 to 0.8 A, which can be associated with the processes of structural relaxation and crystallization occurring in the wires. The run of the dependence of the residual induction on the magnitude of tensile stresses is nonmonotonic in character and is determined by the level of internal hardening stresses of the test wires.     

Simulation of mass transfer in systems with isotropic pair correlation of particles

Results of a numerical analysis of mass transfer in systems of macroscopic particles with various isotropic interaction potentials are presented. Parameters that determine transport properties of nonideal dissipative systems are obtained for a broad class of model potentials. An approximate expression for the diffusivity of interacting particles is proposed. The relationship between diffusivity and viscosity is analyzed for strongly nonideal systems.     

Diffusion of a low-soluble impurity in a solid matrix

An analytical expression for the concentration profile of a low-soluble diffusant in a sample is derived for a high-capacity diffusion source. The model is checked by determining the diffusion coefficient of yttrium in beryllium.     

Determination of the glueball mass spectrum with allowance for spin-orbital interactions

The mass spectrum of a coupled state is analytically determined. The mechanism of production of a constituent mass of particles forming a coupled state is explained. The change of the coupled state and constituent particle component masses attendant to changes of the coupling constant is analyzed. The mass spectrum of a two-gluon glueball is determined with allowance for spin-orbital and spin-spin interactions.__________Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 33–41, December, 2004.     

Mossbauer investigations of corrosion environment influence on Fe valence states in oxide films of zirconium alloys

Mössbauer investigations about iron atom redistribution in oxide films of zirconium alloys subjected to corrosion at 500°C in pure oxygen and water pair have been analysed. The alloys were also subjected to autoclave conditions at a pressure of 10.0 MPa and autoclave conditions at 350°C and at a pressure of 16.8 MPa, using distilled water and water with additives of lithium and fluorine. It is shown that, depending on the corrosion environment, various compounds of iron, such as α-Fe₂O₃, Fe₃O₄, and FeO, as solid solutions of iron in ZrO₂ are formed in oxide films.