Properties of solutions of methyl cellulose blends with poly(N-methyl-N-vinylacetamide) in water and dimethylacetamide and of the related composite films

The rheological properties of dilute and moderately concentrated solutions of methyl cellulose blends with poly(N-methyl-N-vinylacetamide) in water and dimethylacetamide are studied, and the stressstrain characteristics of the composite films based on these blends are estimated. DSC, X-ray diffraction, and thermomechanical analysis are used to investigate the structural organization of composite films, to estimate the temperatures of relaxation transitions, and to determine the composition ranges in which the polymers are compatible and form mixed structures.     

Olefin epoxidation with bis(trimethylsilyl) peroxide catalyzed by inorganic oxorhenium derivatives. Controlled release of hydrogen peroxide.

The replacement of organometallic rhenium species (e.g., CH(3)ReO(3)) by less expensive and more readily available inorganic rhenium oxides (e.g., Re(2)O(7), ReO(3)(OH), and ReO(3)) can be accomplished using bis(trimethylsilyl) peroxide (BTSP) as oxidant in place of aqueous H(2)O(2). Using a catalytic amount of a proton source, controlled release of hydrogen peroxide helps preserve sensitive peroxorhenium species and enables catalytic turnover to take place. Systematic investigation of the oxorhenium catalyst precursors, substrate scope, and effects of various additives on olefin epoxidation with BTSP are reported in this contribution.     

Computer analysis of the band contour of the photoelectron spectrum

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 53, No. 2, pp. 236–242, August, 1990.     

The light pressure force and the friction and diffusion coefficients for atoms in a resonant nonuniformly polarized laser field

The motion of slow atoms with degenerate energy levels in a resonant, nonuniformly polarized laser field is described by the Fokker-Planck equation for the atomic distribution function in phase space in terms of the semiclassical approach. Field gradient expansions are used for the spatially nonuniform coefficients of the equation. For closed atomic transitions J _g =J→J _e =J+1 (J _g and J _e are the total angular momenta of the ground and excited states, respectively), new analytical results are presented for the light pressure force and the friction and diffusion coefficients in momentum space. These results allow the kinetic effects (laser cooling, localization in optical potential wells, etc.) in a field of arbitrary one-, two-, or three-dimensional configuration to be investigated. In several cases, the new contributions to the friction coefficient are interpreted qualitatively.     

Effect of phase transitions of helium-3 in pores of wood carbonizate on the spin kinetics of 3He nuclei

The time of the nuclear magnetic relaxation of ³He gas in pores of Astronium carbonizate powder is studied as a function of gas pressure. Using the results of the measurements of the spin-echo amplitude, the dependences of the rates of spin-lattice and spin-spin relaxations on the number of helium atoms on the surface, in pores, and in the interparticle space of carbonizate powder have been determined. Analysis of the relaxation rates allows the identification of three possible basic phases of ³He in the system under consideration: solid film, gas phase, and liquid. Moreover, the character of spin kinetics in transitions between these phases has been determined.     

Forced vibrations of coaxial reinforced cylindrical shells during interaction with a fluid

Rostov State University Scientific-Research Institute of Mechanics and Applied Mathematics, Rostovon-Don. Translated from Prikladnaya Mekhanika, Vol. 25, No. 12, pp. 63–68, December, 1989.     

The Fibonacci-Penrose semigroup formalism and morphogenetic synthesis of quasicrystal mosaics

We construct the group bundle for the inverse Fibonacci semigroups in the axiomatic approach framework. The proper Fibonacci semigroup is the corresponding group bundle for the Penrose semigroups, which can be interpreted as the generating grammar of the morphogenetic synthesis of the pentasymmetric Penrose parquet in the numbers of tiling by golden rhombuses. This morphogenetic synthesis of the Penrose parquet satisfies the scaling principle. Parquet plates are not absolutely rigid, and the relations between their metric characteristics are governed by the golden section and other magic numbers. The characteristic form factors of three-level dual alphabets are the corresponding invariants. We realize the morphogenetic synthesis in the examples of square-octagonal and bihexagonal lattices. We consider cumulative properties of magic series and the evolutionary aspects of semigroup orbits in the entropy representation.