Mechanochemical synthesis and compaction of intermetallic alloys containing nanocrystalline substructure elements

The peculiarities of phase formation during mechanochemical treatment of mixtures containing elementary Ni and Al components in an atomic ratio of 3: 1 and graphite in various amounts are considered. As a result of mechanochemical treatment, supersaturated solid Ni(Al, C) fcc solutions form, in which the content of carbon reaches 0.5–0.6 atom/unit cell. When perovskite carbide, Ni₃AlC _x , is in the equilibrium ordered state, the amount of carbon is x ≤ 0.3 atom/unit cell. Ni(Al, C) solid solutions obtained by mechanochemical synthesis are compacted by hot isostatic pressing (HIP) and are found to lead to the formation of a microstructure in which micrograins (2–5 μm) of ordered Ni₃AlC _x phase are surrounded by nanoscale graphite particles (<50 nm). In order to bind the graphite released during heating, carbide-forming elements (i.e., Nb, Ti, and Hf) are added to a mechanochemically synthesized Ni(Al, C) solution. Subsequent short-term mechanochemical activation of these mixtures results in homogeneous distribution of carbide-forming elements without carbides being formed. After compaction by means of HIP, solid solutions undergo ordering, and excess carbon forms nanocarbides at the grain boundaries.     

Research in the imidazole series

It was established on the basis of an investigation of the mass spectra that in the reaction of 2-chlorobenzimidazoles with unsymmetrical olefin oxides and secondary β -halo alcohols, of the two possible isomers only 1-[β-alkyl(aryl)-β-hydroxyethyl] derivatives of benzimidazole are formed.     

Decay phase of energetic electrons and protons in solar cosmic ray events

The decay phase of solar energetic particle (proton and electron) events is considered. The propagation mechanisms for particles of different kind may differ in the same events, which should manifest itself in the pecularities of their decay phases. To compare the propagation parameters of protons and electrons, we used the data of simultaneous measurements of few-MeV proton and few-hundred-keV electron fluxes from IMP-8 CPME and SOHO COSTEP. Nearly half of clear-shaped simultaneously measured electron and proton decays have similar character (exponential or power-law), suggesting that at least in a part of events electrons can be subjected to the same propagation mechanisms as protons.     

Condensed imidazo-1,2,4-azines. 13. Reaction of 1,2-diaminobenzimidazole with 3-benzoyl-2-propanonic acids

Refluxing 1,2-diaminobenzimidazole with 3-benzoyl-2-propanonic acids in methanol gives the corresponding salts, viz., 1,2-diaminobenzimidazole 3-benzoyl-2-propanonates, which are converted to 2-benzoylmethyl-1,2,4-triazino[2,3-]-benzimidazol-4H-3-ones upon heating in high-boiling organic solvents.See [1] for communication 12.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1402–1405, October, 1985.     

Series of events with similar decay times and the homogeneity of the inner heliosphere

Exponential decay phases of electron and proton fluxes in solar energetic particle (SEP) events are investigated for the period from 1974 to 2010 on the basis of IMP-8 and SOHO spacecraft data. The exponential decay of particle fluxes is possible under the invariable integral properties of the surrounding space, which is homogeneous and quasi-stationary in a certain near-solar sector. Consecutive events (sequences of events) with similar exponential decays allow these sectors of space homogeneity to be expanded up to 90°, and sometimes up to 180° and more.