Study of the peak effect phenomenon in single crystals of 2H-NbSe2

The weakly pinned single crystals of the hexagonal 2H-NbSe₂ compound have emerged as prototypes for determining and characterizing the phase boundaries of the possible order-disorder transformations in the vortex matter. We present here a status report based on the ac and dc magnetization measurements of the peak effect phenomenon in three crystals of 2H-NbSe₂, in which the critical current densities vary over two orders of magnitude. We sketch the generic vortex phase diagram of a weakly pinned superconductor, which also utilizes theoretical proposals. We also establish the connection between the metastability effects and pinning.     

Magnetism in disordered magnetic Fe82−xNixCr18

The zero field μSR-method has been used to study the magnetism in the disordered magnetic alloy Fe_82−xNi_xCr₁₈ near the three-critical, pointx=25. The dynamic and static local field distributions are analyzed. The difference between spin-glass states obtained either from the paramagnetic or after the double transition is discussed.     

Utilization of waste solutions in perovskite technology

A scheme for utilization of chloride solutions of complex composition with α-and β-activity of up to 35 and 28 kBq 1^?1, respectively, is suggested.     

Reaction of alkoxyl organomercury compounds with chloroform

Conclusions Derivatives of trichloromethylmercury RHgCCl₃ (R=n-C₃H₇, cyclo-C₆H₁₁, C₆H₅CH₂, and C₆H₅), which are stable in the absence of air, were obtained in almost quantitative yield by the reaction of the corresponding mercury tert-butoxides RHgOC(CH₃)₃ with chloroform at room temperature.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2803–2805, December, 1968.     

Reactions of 5,6,7,8-tetrafluoro-4-hydroxycoumarin derivatives with benzylamine and aniline

5,6,7,8-Tetrafluoro-4-hydroxycoumarin reacted with benzylamine under mild conditions to give a stable salt, while its refluxing with aniline or benzylamine in xylene afforded 5,6,7,8-tetrafluoro-4-phenyl(benzyl)aminocoumarins. Reactions of 3-acetyl(acetimidoyl)-5,6,7,8-tetrafluoro-4-hydroxycoumarins with benzylamine followed different pathways, depending on the solvent. Condensation at the acyl substituent can be accompanied by replacement of the F atom in position 7. 3-Acetylcoumarin formed a salt, while 3-acetimidoylcoumarin yielded a 7-monosubstituted product. 3-Acetyl(acetimidoyl)-5,6,7,8-tetrafluoro-4-hydroxycoumarins reacted with aniline to give only 5,6,7,8-tetrafluoro-4-hydroxy-3-(N-phenylacetimidoyl)coumarin. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1170–1174, July, 2006.     

μSR study of vortex structure mobility and penetration depth in Bi2Sr2CaCu2O2-δ textured sample

The giant mobility of the magnetic flux in FrFC and ZFC conditions have been studied in textured sample Bi₂Sr₂CaCu₂O_2- bySR. The comparison of results obtained in both cases showed that it is difficult to explain this phenomenon by only thermally activated flux creep and the melting of vortex lattice must be considered. The magnetic field dependence of the melting temperature was obtained for H<90mT. It is shown that the possibility of vortex motion does not affect the results of FC-measurements.     

Investigation of the effects of hydration and amphiphilic properties of nootropic drugs of piracetam and pramiracetam

An investigation of the hydration and amphiphilic properties of the piracetam and pramiracetam molecules has been conducted by theoretical conformational analysis and the Monte Carlo method; their localization and orientation at the water-lipophilic medium interface have been determined, which made it possible to explain the characteristics of the pharmacological action of the drugs.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 4, pp. 355–358, July–August, 1992.     

Reactions of hexamethylditin and trimethyltin sulfide withN-thio-derivatives of phthalimide

The initial formation of organotin derivatives with Sn-S-N bonds in heterolytic reactions of hexamethylditin or trimethyltin sulfide withN-(chlorothio)phthalimide is suggested. Subsequent interaction of these compounds with sulfenyl chloride affordsN, N-thioorN, N-dithiobisphthalimide. Homolytic reaction of hexamethylditin withN, N-dithiobisphthalimide also occursvia an organotin intermediate, which, in the absence of a nucleophilic reagent, eliminates sulfur and converts intoN-trimethylstannylphthalimide.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2111–2114, December, 1993.     

Use of AM1 and PM3 methods for the investigation of energies and structures of compounds O=PXYZ,S=PXYZ

Novosibirsk Institute for Bioorganic Chemistry, Academy of Sciences of the USSR, Military Section 61469. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 4, pp. 171–173, July–August, 1990.