Structure and electronic spectra of 2-phenylbenzimidazoles. Quantum chemical analysis of the intramolecular hydrogen bond

Institute of High-Molecular-Weight Compounds, Russian Academy of Sciences. Leningrad State University Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 5, pp. 20–27, September–October, 1992.     

Particular cases of resonant tunneling in multibarrier quantum structures

An investigation was made of the resonance conditions in systems of one-dimensional potential barriers of a general kind. The types of systems are identified and the conditions determined which are necessary for observing a broad resonance in which the first three derivatives of the energy transmission coefficient are equal to zero. The conditions are found for observing an isolated resonance with complete transparency on a background of resonances with incomplete transparency.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 49–53, August, 1993.     

Relationship between the chemical structure and pharmacological action of cardiac glycosides of the strophanthidin series

The possibility has been shown of finding and creating highly effective cardiotonic drugs for pediatric practice on the basis of cardenolides obtained by the chemical transformation of natural cardiac glycosides.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 581–585, July–August, 1995. Original article submitted November 21, 1994.     

Rare‐earth site splitting in Sm3MoO7

Trisamarium molybdenum heptaoxide, Sm₃MoO₇, is isomorphous with Ln₃MoO₇ (Ln = La and Pr). The crystal structure consists of chains of corner‐linked MoO₆ octahedra running parallel to the b axis and separated from each other by seven‐ or eight‐coordinate Sm–O polyhedra. In contrast to La₃MoO₇ and Pr₃MoO₇, a splitting of one Sm site into two positions is observed.     

Optical Magnus effect in metamaterials fabricated from ferromagnetic microwires

In homogeneous negative phase velocity media, the Doppler and Cherenkov-Vavilov effects and the refraction and pressure of light are anomalous: they are inverse with respect to the corresponding effects in conventional media. Using the geometrical optics approximation, it is shown that the optical Magnus effect in inhomogeneous negative phase velocity media is also anomalous. The effect is demonstrated by considering a metamaterial consisting of parallel amorphous ferromagnetic microwires in a magnetic field. The metamaterial proves to be a left-handed one in the realistic region of the electromagnetic spectrum. The optical properties of such a left-handed medium can be controlled by the external magnetic field.     

X-ray fluorescence determination of bromine in halogenated organic compounds using quasisolid emitters

A series of quasi-solid emitters is proposed for the X-ray fluorescence determination of bromine in different bromine-containing compounds. It is shown that sucrose-based glasses are the best emitters for analyzing alkali solutions of halogenated organic compounds, saccharose-based glasses and polymer films are best for analyzing powder samples, and organic gels offer most promise for analyzing liquid (at normal conditions) samples. It is noted that the proposed method can expand the possibilities of commercially produced element analyzers, which are currently intended for determining only C, H, O, N, and S in organic compounds and cannot be used for determining halogens.