Determination of the spectral parameters of doped nematochiral composites for optical switching systems

A simple equation describing the optimum relation of the parameters of doped nematochiral cells for use in real systems of switching and limiting of laser radiation is obtained based on analytical estimates. The adequacy and feasibility of the derived relation is confirmed experimentally.     

Investigation of correlation properties of backscattering by discrete inhomogeneities

Physical modeling of acoustic signal backscattering by discrete random inhomogeneities is performed. The behavior of the transverse correlation radius of the scattered field amplitude is studied. Its experimental dependences on the transducer aperture, on the angle of sounding of an inhomogeneity-containing plane, and on the correlation properties of the scatterer position on this plane are derived. Qualitative theoretical models in the framework of the theory of single scattering are proposed which provide an explanation to the phenomena observed.State University, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 38, Nos. 1–2, pp. 106–109, January–February, 1995.     

13,17,53,57-Tetraphenyl-13,17,53,57-tetrathio-3,7-dithia-1,5(1,5)-di(1,5-diaza-3,7-diphosphacyclooctana)-2,4,6,8(1,4)-tetrabenzenacyclooctaphane with an unusual conical-like conformation

1³,1⁷,5³,5⁷-tetraphenyl-1³,1⁷,5³,5⁷-tetrathio-3,7-dithia-1,5(1,5)-di(1,5-diaza-3,7-diphosphacyclooctana)-2,4,6,8(1,4)-tetrabenzenacyclooctaphane 2b was obtained by sulfurization of the corresponding macrocyclic tetraphosphine 1b. The structure of the inclusion complex of tetrasulfide 2b with DMF was investigated by the X-ray crystal structure analysis. A novel for this type of cyclophanes and relatively rare conical-like conformation of the macrocycle was found. A methyl group from one of the solvating DMF molecules penetrates the macrocyclic cavity of 2b from the side of the wider rim. According to quantum-chemical simulations, this may be the reason of the unusual conical conformation of 2b because the cavity of the macrocycles of this type is highly flexible. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Influence of the modification process on the properties of AlOOH nanofibers

A procedure of bulk modification of aluminum oxhydroxide AlOOH during synthesis using manganese(II) ion as the modifying agent was studied. The physicochemical properties of the modified AlOOH fiber were examined. It was found that the presence of manganese(II) ions in solution affected the composition of the products of the reaction between aluminum nanopowder and “liquid water.” The phase composition of the reaction products was examined by X-ray diffraction and differential thermal analysis techniques. It was shown that, for solutions with the manganese ion concentration varying from 0.02 × 10^?3 to 40 × 10^?3 mol l^?1, the degree of amorphicity and the proportion of the AlOOH phase tended to increase. A modification mechanism involving the participation of manganese ions in the AlOOH nanofiber growth process was proposed.