Critical Grain Size at Meso-Level after Deformation of Polycrystalline Metals and Alloys in Low-Stability State

Russian Physics Journal - The paper deals with the dislocation and dislocation-disclination substructures of polycrystalline FCC alloys Cu–Al and Cu–Mn modified by tensile deformation....     

Dislocation Structure Evolution in Low-Stability States of Solid Solutions of Alloys Under Their Deformation

Russian Physics Journal - The results of a study of the dislocation structure evolution in polycrystals of homogeneous solid solutions in low-stability states in Cu-Mn-based alloys with FCC crystal...     

The influence of the hall effect on the current structure in a plasma flow with a spatially periodic magnetic field

The structure of the electric fields and current is studied for stationary plasma flow in an axially symmetric, spatially periodic magnetic field. The problem is solved in the magnetohydrodynamic approximation with allowance for the Hall term in the generalized Ohm's law equation. It is assumed that the magnetic Reynolds number and the interaction parameter are small.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 5, pp. 11–16, September–October, 1972.The author thanks N. A. Khizhnyak and A. A. Kalmykov for useful discussions.     

Synthesis of Highly Dispersed Zirconium Diboride for Fabrication of Special-Purpose Ceramic

Reduction of zirconium dioxide with boron carbide and nanofibrous carbon in argon yielded a highly dispersed powder of zirconium diboride. Characteristics of zirconium diboride powders were examined by various analytical methods. The material obtained is represented by a single phase, zirconium diboride. Powder particles are for the most part aggregated. The average size of particles and aggregates is 10.9–12.9 μm with a wide size distribution. The specific surface area of the samples is 1.8–3.6 m² g^–1. The oxidation of zirconium diboride begins at a temperature of 640°C The optimal synthesis parameters were determined: ZrO₂: B₄C: C molar ratio of 2: 1: 3 (in accordance with stoichiometry), process temperature 1600–1700°C, synthesis duration 20 min.     

Hexafluorosilicates of cobalt(II) complexes with dimethylsulfoxide and dimethylformamide

New double complexes [Co(DMSO)₆][SiF₆] ? 2H₂O (I) and [Co(DMF)₃(H₂O)₃][SiF₆] ? DMF (II) have been synthesized and studied by IR spectroscopy and X-ray diffraction. Crystals of complex I belong to the tetragonal symmetry system, space group R3?, Z = 3, a = 11.8232(3) Å, c = 18.4699(5) Å, V = 2235.97(10) ų, ρ_calc = 1.573 g/cm³. Crystals of complex II are triclinic, space group P1?, Z = 2, a = 8.6264(4) Å, b = 10.1419(4) Å, c = 13.9657(6) Å, α = 100.847(2)°, β = 98.549(2)°, γ = 93.479(2)°, V = 1181.71(9) ų, ρ_calc = 1.539 g/cm³.     

Quantittive determination of amino sugars in bacterial lipopolysaccharides

A modification of the method of quantitatively determining amino sugars in polysaccharide preparations of bacterial origin is described which excludes the influence of the mixture of amino acids and monosaccharides on the result of the analysis. The modification is based on differences in the extraction capacity of organic solvents in relation to the various chromophores obtained in the Elson-Morgan reaction from amino sugars and from the mixture of amino acids and monosaccharides. It has been found that the modification described is distinguished by a high sensitivity, specificity, and reproducibility of the results. The standard deviation calculation for 10 determinations does not exceed 4%. The method is simple to perform and it requires uncomplicated equipment and small amounts of reagents.Pacific Ocean Institute of Bioorganic Chemistry, Far-Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 739–743, November–December, 1985.     

Mössbauer research of magnetic particles in medicinal ointments

Stability of the properties of magnetite particles in novel medicinal magnetic ointments of multipurpose application was studied using Mössbauer spectroscopy. Comparative analysis of the results obtained by model fitting of⁵⁷Fe nuclei spectra with those known for the system Fe₃O₄-γ-Fe₂O₃ allowed to identify the phase composition of the particles. This composition, as well as that of the initial pure component in the form of a highly dispersed fraction (～100 Å), differs noticeably from the stoichiometric one. Despite their small sizes, the particles exhibit no superparamagnetism (in the temperature range from 95 to 300 K). Radiative sterilization of the ointments has no effect on the magnetic component composition.