Redistribution of dislocations in silicon near stress concentrators

The distribution of defects in dislocation tracks in silicon plates was studied for various indentation angles. The regularities of variations in the linear density and maximum path of dislocations in slip bands are established. A model is proposed to describe the distribution of dislocations in the dislocation tracks. By fitting the theory to the experimental data, the dependence of this distribution on the energy relaxation time is determined.     

Synthesis details and solubility product for cobalt hydroxo salt Co(OH)<Subscript>1.8</Subscript>Cl<Subscript>0.2</Subscript>

The hydroxo salt Co(OH)_1.8Cl_0.2 is precipitated by a deficit of OH^? ions from dilute CoCl₂ solutions under the conditions that inhibit the appearance of local excesses of OH^? ions. The three-variable method is used to determine the solubility product for this compound. A linear correlation between the composition and solubility product is found for Co(OH)₂, Co(OH)_1.8Cl_0.2, and Co(OH)_1.5Cl_0.5.     

Synthesis of 2-amino-4,5,7-triarylimidazo[1,5-b]pyridazines

The reaction of 4-aryl-1,2-diaminoimidazoles with 1-aryl-2,3-dibromo-3-(4-nitrophenyl)propanones, 2-bromo-1-phenyl-3-(4-chlorophenyl)propenone, and 1,3-diarylpropynones yields 2-amino-4,5,7-triarylimidazo[1,5-b]pyridazines. The structure of one of these products was determined by x-ray diffraction analysis. Kharkov State University, 310077 Kharkov, Ukraine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1397–1403, October, 1998.     

Biphonons in quasicrystals

The spectrum of coupled optical biphonon vibrations in quasicrystals with variation of the atom-atom interaction in accordance with the Fibonacci sequence is investigated. For two-phonon states with strong anharmonicity of the vibrations, a system of recursion equations, which is more complicated than the previously employed system for one-phonon states, is obtained. Calculations using this system made it possible to determine the spectrum of biphonon vibrations in a quasicrystal. It is shown that, on the low-frequency edge of the biphonon band, a scaling-type fine structure of the same form as in biphonon spectra of fractal lattices exists in the density of states. It is found that the energy dependence of the density of states is periodic on a logarithmic scale. The period of this dependence is determined. It is noted that the resonance structure in the density of states is of a nonstandard form in the high-frequency region of the biphonon band. Fiz. Tverd. Tela (St. Petersburg) 39, 163–170 (January 1997)     

Anomalies in the physical properties of the α form of bismuth oxide

Several of the physical properties of α-Bi₂O₃ have been studied in the temperature region above room temperature: the thermal expansion, the thermally stimulated current, the permittivity, the electrical resistance, and the specific heat. X-ray diffraction measurements and a thermogravimetric analysis have also been carried out. Several unusual properties in the physical properties of bismuth oxide have been detected in the temperature interval 450–570 K: exothermic maxima on the DTA and DSC curves, a small maximum and a sharp increase of the permittivity of the single crystal, a jump and a change of sign in the thermally stimulated current, and a sharp falloff of the electrical resistance of ceramic samples. At the same time, no appreciable changes in the monoclinic structure of α-Bi₂O₃ have been recorded in the indicated temperature interval. Fiz. Tverd. Tela (St. Petersburg) 39, 865–870 (May 1997)     

Quantum cyclotron resonance of two-dimensional holes in the Ge layers of Ge-Ge1−x Six heterostructures

Quantum cyclotron resonance of two-dimensional holes in strained germanium layers of the periodic heterostructure Ge-Ge_1−x Si_x has been observed and investigated for the first time. The results are compared with the data of electrophysical measurements in strong magnetic fields. A clear dependence of the magnitude of the longitudinal effective mass of the holes on the absolute magnitude of the elastic deformation of the germanium layers (splitting energy of the hole subbands) is observed. Fiz. Tverd. Tela (St. Petersburg) 39, 2096–2100 (November 1997)     

Derivation of the Hydrodynamic Equations in the Framework of the Bogoliubov Functional Hypothesis

We generalize the Bogoliubov functional hypothesis to the case of multiparticle interaction depending on both the coordinates and momenta of particles. We illustrate this with the examples of two weakly relativistic models: the Darwin model in the theory of charged particles and the Fock model in the general theory of relativity. For these models, based on the chain of the BBGKY equations, we calculate weakly relativistic corrections to the classical transport coefficients and find the conditions under which there is no bijective relation between the parameters of the local equilibrium distribution and the hydrodynamic variables.