Quantum concept of the rearrangement of a crystal lattice

Using quantum considerations based on the concept of lattice rearrangement waves, we carried out an analysis of processes of rearrangement of a crystal lattice occurring on a moving front (interface) of crystal rearrangement. For the introduction and quantization of these waves we use the method of acoustomechanical analogy and the Sommerfeld quantum conditions. We calculate the energies and the propagation velocities of the lattice rearrangement waves. Along with quanta having a certain momentum, quanta that have a certain angular momentum are introduced into consideration. On the basis of the concepts developed, we suggest a new expression for calculating the probability of thermofluctuational processes in a crystal. We perform a numerical analysis of the rate of growth of the -phase in iron in the process of --conversion. Satisfactory agreement with experiment is obtained. We discuss the limitations and prospects of further development of the concept suggested. For direct experimental verification of the concept we propose to investigate the diffraction of electrons and other particles on the lattice rearrangement waves, i.e., in the process of phase conversions or disintergration of crystals.Branch of the P. N. Lebedev Physical Institute of the Russian Academy of Sciences, Samara. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 68, No. 1, pp. 136–142, January–February, 1995.     

Numerical investigation of convective flows of a highly inhomogeneous gaseous medium

Equations of convection in a gas are analyzed and a computational algorithm that is efficient when the condition gh/RT1 is satisfied for an arbitrary (fairly large) temperature drop is proposed. Calculations of convection occurring in steady nonuniform heating of walls are performed for axisymmetric argoncontaining volumes of different shape. Results of these calculations demonstrate the establishment of steady and periodic motions of the gas.Academic Scientific Complex A. V. Luikov Institute of Heat and Mass Transfer of the Academy of Sciences of Belarus, Minsk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 68, No. 6, pp. 983–990, 1995.     

State and prospects of inhibitor protection of the metal resources of the Ukraine

At present, the overall losses caused by corrosion in the Ukraine are very high and increase constantly owing to an increase in the aggressiveness of the environment and a lack of corrosion-resistant materials and anticorrosion technologies. The corrosion-mechanical fracture of metals (corrosion fatigue or corrosion cracking) proves to be the most dangerous type of corrosion since it occurs without visible changes in the appearance of structures. This is true, first of all, for pipelines, chemical and power equipment, municipal utility services, etc.The Ukrainian Association of Corrosionists has recently been founded with the aim of intensifying anticorrosion activities. The Association has about 40 organizational members (including academic and specialized institutes and industrial enterprises) and about one hundred individual members—prominent experts in corrosion science. The Technical Committee TC-85 Corrosion of Metals and Alloys was founded by the State Committee on Standardization and Metrology of the Ukraine. In 1993, the Ukraine became a member of the International Corrosion Council.In view of the urgency of this problem, the Editorial Board of Fiziko-Khimicheskaya Mekhanika Materialov begins a series of survey, problem, and discussion papers devoted to the problem of protection of metals against corrosion. Scientists and experts are invited to discuss this and related problems in our journal. The present work opens the series. We consider and characterize the main groups of corrosion inhibitors used in industry and indicate their developers and producers. The addresses of the Collection and computer bank of corrosion inhibitors and inhibited materials are also presented.Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 30, No. 1, pp. 11–17, January–February, 1994.     

Nonstationary Infrared Testing of Coatings on Exterior and Interior Surfaces of Metal Shells

Technical Physics Letters - A new method for nondestructive testing of coatings on exterior and interior surfaces of metal shells is proposed that is based on video monitoring of the infrared...     

Mechanisms of Current Transfer in Electrodeposited Layers of Submicron Semiconductor Particles

Technical Physics Letters - Current–voltage (I–V) characteristics of conductance in multigrain layers of submicron particles of silicon, gallium arsenide, indium arsenide, and indium...     

Quantized Massive Gauge Fields and Hole-Induced Spin Glass Mechanism in Underdoped Cuprates

We have discussed the restoration mechanism of the spontaneous symmetry breaking, C ₂ spatial symmetry breaking mechanism, and spin glass-like mechanism in high- T _c cuprates from the standpoint of field-theoretical formula. It is suggested strongly that quantized massive gauge fields, which contain effects of spin fluctuations, charge fluctuations, and phonons, might be mediating Cooper pairing in high- T _c cuprates.     

Electrical and Dielectric Properties of Y<Superscript>3+</Superscript>-Substituted Barium Hexaferrites

In this study, Y³⁺ ion-substituted M-type barium hexaferrites (BaM; BaFe₁₂O₁₉) were fabricated via facile ceramic route. As-prepared powders were characterized by X-ray powder diffractometry (XRD), Fourier transform infrared (FT-IR) spectroscopy, and impedance spectroscopy. XRD (Rietveld) analyses confirmed the presence of a single characterization of all samples (except x = 0.0 and 0.1 samples). The crystallite sizes of products are found in the range of 47.2–63.2 nm. Spectral analysis (FT-IR) also presented the formation of spinel structure for all products. The ac conductivity of the substituted samples was found to initially decrease slightly with increase in Y³⁺ compared with unsubstituted, and then variation tendency changes at the medium substitution ranges are observed with a different attitude against temperature. In the end, the lower conductivity for high substitutions is recorded and increases as functions of frequency while it also increases with the elevation of temperature. It was observed that ac conductivities of products increased by increasing frequency which indicate that observed ac conductivity is due to both electronic and polaron hopping mechanism.     

Preparation of Ti<Subscript>3</Subscript>SiC<Subscript>2</Subscript> through reduction of titanium dioxide with silicon carbide

This paper describes the reduction of titanium dioxide with a mixture of silicon carbide and silicon powders at a temperature of 1550°C under vacuum. It has been shown that the use of the combined reductant enables the preparation of the ternary phase Ti₃SiC₂ through concurrent carboand silicothermic processes. The optimal compositions for Ti₃SiC₂ formation are TiO₂ + (1.5–x)SiC + 2xSi with x = 0.4–0.5. The Ti₃SiC₂ yield then reaches 96 wt %.