Experimental study of laser-induced processes on the surfaces of carbonaceous materials with simultaneous measuring of their temperatures

Results are presented from experiments on monitoring laser-induced processes (heating, melting, and ablation) on surfaces of carbonaceous materials (glassy carbon, pyrocarbon) using a laser display and according to the brightness temperature determined during these processes with a high-temperature pyrometer. The melting brightness temperature of glassy carbon (2720 ± 15 K) is determined using a continuouswave fiber laser. Some wave structures are revealed. No melting of pyrocarbon was observed over the range of powers and temperatures. The surfaces ablated after heating.     

Transformations of the Burnett components of transport relations in gases

The well-known expressions for the Burnett components of the stress tensor and the heat flux vector in a monatomic gas are transformed to a more effective form. The greatest simplifications are obtained for the stress tensor when using the usually employed approximate values of the Burnett transport coefficients, which are exact for the gas consisting of Maxwellian molecules.     

Properties of doubly heavy baryons in the relativistic quark model

Mass spectra and semileptonic decay rates of baryons consisting of two heavy (b or c) and one light quark are calculated in the framework of the relativistic quark model. The doubly heavy baryons are treated in the quark-diquark approximation. The ground and excited states of both the diquark and quark-diquark bound systems are considered. The quark-diquark potential is constructed. The light quark is treated completely relativistically, while the expansion in the inverse heavy-quark mass is used. The weak transition amplitudes of heavy diquarks bb and bc going, respectively, to bc and cc are explicitly expressed through the overlap integrals of the diquark wave functions in the whole accessible kinematic range. The relativistic baryon wave functions of the quark-diquark bound system are used for the calculation of the decay matrix elements, the Isgur-Wise function, and decay rates in the heavy-quark limit.     

ECSim2.0 package and simulation of X-ray emulsion chamber experiments

The ECSim 2.0 package is being developed on the basis of the ECSim software package to simulate the development of nuclear-electromagnetic cascades initiated by different particles in a layered medium. Some characteristics of ECSim 2.0 and the results obtained using this package in simulation of the passage of electrons and γ rays through the gamma block of X-ray emulsion chambers in the Pamir Collaboration experiment are discussed. The results obtained are compared with the data of other researchers.     

Dynamics of a domain wall in two-layer uniaxial magnetic films with gyromagnetic ratios of different signs in the layers

Motion of an isolated domain wall in two-layer uniaxial magnetic films with gyromagnetic ratios of different signs in the layers is first investigated by solving numerically the Slonczewski equations. The mode of stationary domain wall motion with the angle of magnetization vector departure from the wall plane exceeding π is established. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 50–53, May, 2007.     

The kinetic regularities, products, and mechanism of the thermal decomposition of dimethyldioxirane. The contribution of molecular and radical reaction channels

The products and kinetics of the thermal decomposition of dimethyldioxirane (DMDO) were studied. The reaction proceedsvia three parallel pathways: isomerization to methyl acetate, oxygen atom insertion into the C−H bond of a solvent molecule (acetone), and the solvent-induced homolysis of the O−O bond in the DMDO molecule. The contribution of the latter reaction channel isca. 23% at 56°C. The overall kinetic parameters of DMDO thermolysis in oxygen atmosphere were determined. The free radical-induced DMDO decomposition occurs in an inert atmosphere. The formal kinetics of this reaction was investigated. The mechanism of the DMDO thermolysis is discussed. Dedicated to Professor E. T. Denisov on the occasion of his 70th Birthday. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1344–1354, August, 2000.     

Activation of the S-S bond in diphenyl disulfide by nickel complexes and its reaction with butadiene

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, p. 747, March, 1989.     

New phosphonium salts based on 3-(diphenylphosphino)propanoic and ω-haloalkanoic acids

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N-Substituted tetrahydro-1,3-oxazines and oxazolidines. 1. A new version of the Mannich reaction involving amino alcohols

A new version of the Mannich reaction involving amino alcohols (3-aminopropan-1-ol and aminoethanol) was developed. These compounds react with formaldehyde and CH or NH acids to give N-substituted tetrahydro-1,3-oxazines or oxazolidines.