Catalytic Activity of Nickel Nanoparticles in the Reaction of Reduction of Nitroarenes

Techniques for the production of nickel and nickel-cobalt nanoparticles and of their composites with polyvinylpyrrolidone were developed. The catalytic activity of the resulting compounds towards reduction of substituted nitroarenes was examined.     

Detonation wave initiated by explosive condensation of supersaturated carbon vapor

An experimental study of the influence of condensation of supersaturated carbon vapor formed behind reflected shock waves on the process of propagation of a shock wave and formation of a detonation wave of condensation is carried out. Highly supersaturated carbon vapor was formed from thermal decay of unstable carbon suboxide C₃O₂ → C + 2CO behind a shock wave in mixtures containing 10–30% C₃O₂ in Ar. This reaction was followed by fast growth of condensed carbon particles, accompanied by heat release. Experiments have shown a considerable temperature and pressure increase in the narrow zone behind the wave front, resulting in shock wave amplification and transition to a detonation-like regime. An analysis of the kinetics and heat release in the given conditions and calculations based upon one-dimensional detonation theory have shown that in a mixture of 10% C₃O₂ + Ar, insufficient heat release resulted in a regime of “overdriven detonation”. In a mixture of 20% C₃O₂ + Ar a very good coincidence of measured values of pressure and wave velocity with calculated Chapman–Jouguet parameters is observed. In a 30% C₃O₂ + Ar mixture, an excess heat release caused a slow down of the effective condensation rate and a regime of “underdriven detonation” is observed.     

Synthesis and crystal structure of thiolate-bridged dinuclear platinum(II) complexes

Russian Journal of General Chemistry - Reactions of 2,2′-bipyridine platinum(II) complexes with 2-aminoethanethiol or 2,2′-disulfanediyldi-(ethan-1-amine) afforded new complexes...     

Hypersonic flow past blunt-edged delta wings

A method is proposed for calculating hypersonic ideal-gas flow past blunt-edged delta wings with aspect ratios = 100–200. Systematic wing flow calculations are carried out on the intervals 6 M 20, 0 20, 60 80; the results are analyzed in terms of hypersonic similarity parameters.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 175–179, September–October, 1990.     

Mathematical models in nanooptics and biophotonics based on the discrete sources method

The state of the art of the discrete sources method is reviewed. The method can be used to construct effective numerical models for problems in nanooptics and biophotonics.     

Three-chamber low-output-pressure glow-discharge-based plasma generator as a negatively charged ion source

A stationary glow discharge initiated in a two-chamber inverted gas magnetron is studied. In the third (emission) chamber, such a discharge system generates a plasma that can be subdivided into two, circumferential and near-axis, regions with considerably differing parameters and also provides a pressure difference in desired areas. It is concluded that the device suggested could be used as an efficient continuous-mode plasma generator making it possible to produce negatively charged gas ions. The results obtained may serve as a basis for negative ion source design optimization.     

A Computer Technology for the Discrete Source Method in Scattering Problems

The latest achievements of the discrete source method are reviewed. The method constructs efficient numerical models for the scattering of electromagnetic waves by three-dimensional structures, including structures in the presence of a substrate. The proposed approach remains efficient for scatterers with extreme characteristics, both in free space and in the presence of a layered structure.