Small-angle x-ray scattering in a carbon-sulfur nanocomposite produced from bulk nanoporous carbon

A new nanocomposite material containing approximately 50 vol % S is prepared by filling pores of bulk nanoporous carbon samples with sulfur. The initial nanoporous carbon samples are synthesized from polycrystalline α-SiC through the chemical reaction. A comparative investigation of small-angle x-ray scattering (SAXS) is performed for the prepared nanocomposite and the initial material. The possible changes in the scattering power of the initial material upon filling of its pores with sulfur are considered in the framework of a simple model. The regularities revealed are used to interpret the experimentally observed changes in the scattering power. The size distribution functions of incorporated sulfur nanoclusters in the nanocomposite (or filled nanopores in the initial material) are determined within the Guinier approximation. It is demonstrated that the smallest sized pores (8–16 Å) remain unfilled, whereas the filling factor for larger sized pores can reach several ten percent by volume. The conditions favorable for small-angle x-ray scattering upon filling of the nanopores are analyzed.     

Opportunity for magnetic field spatial‐time correlation research using a μSR^2‐method

It is theoretically shown that in rare gases at P < /100 atm the external electric fields of the order of 100 V/cm could significantly change the value of electron density in the region of μ^- or μ⁺ stopping point and affect the muonic atoms formation in plasma‐chemical reactions. The kinetic model of processes which might explain the results of μSR‐experiments for μ^- in Ne and Ar both with and without external electric field is proposed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Investigation of the extent, rate, and mechanisms of electron-stimulated modification of the C60 fullerite by EELS

A parameter representing the intensity ratio of the two features in the characteristic electron energy loss spectrum that are most sensitive to electron irradiation is proposed for use in characterizing the extent of electron-stimulated modification of fullerite. By normalizing this parameter, we succeeded in obtaining a universal scale for the extent of modification that can be unambiguously related to the π-electron density. The dose dependence of this parameter is shown to be described by one exponential, thus permitting one to conclude that both the polymerization and amorphization of the fullerite are dominated by one mechanism, namely, the formation of intermolecular chemical bonds, which is stimulated by valence-electron excitation. The rate of the electron-stimulated modification, or the dose susceptibility of the material, is defined through the derivative of this parameter. The dependence of this rate on the incident electron energy is obtained. It is shown that structural changes are mainly due to a swarm of numerous secondary and decelerated electrons rather than to the primary electron.     

Synthesis of 1h-pyridazin-4-one derivatives from acetylagetone through its difluoroboryl chelate

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, p. 1690, July, 1988.     

Autowave flows of weakly conducting gas in rough channels in the presence of strong electromagnetic fields

The steady-state flow of a gas in a rough channel in the presence of strong transverse magnetic and electric fields is considered. It is shown that in this case there also exists a periodic regime consisting of a sequence of deceleration waves [5–7]. The periodic regime results from the action of the forces of resistance to the motion of the gas.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 152–158, January–February, 1989.The authors wish to thank A. A. Barmin and A. G. Kulikovskii for valuable discussions.