Crystallization and Conditions for Fabricating Dense Ingots from High-Nitrogen Steels

Metal Science and Heat Treatment -     

Corrosion of steels due to the action of microorganisms

The susceptibility of variously alloyed structural steels to microbiological corrosion in media enriched with hydrogen sulfide and favorable for reproduction of sulfate-reducing bacteria is studied. It is shown that stainless steels 05Kh17N4DB and especially nitrogen-alloyed steel 05Kh13A possess a higher anti-adhesive capacity with respect to corrosion-active microorganisms and resistance to microbe fouling and formation of corrosion-active biofilms than the conventional structural steel 38KhGM. It is assumed that the action of nitrogen can be connected with formation of biocide substances.     

The spectrum of real-space indirect magnetoexcitons

This paper discusses two-dimensional excitons with spatially separated electrons and holes in coupled quantum wells and vertically coupled quantum dots in a transverse magnetic field for a wide range of two characteristic quantities of the problem-the distance between wells or dots d and the magnetic field H. Dispersion relations E _nm(P) are calculated for coupled quantum wells at various values of d and H (where P, the magnetic momentum along the well, is a conserved quantity in the magnetic field). The spectrum is calculated by numerically diagonalizing the Hamiltonian in various bases—either a Coulomb or a Landau basis (the choice of basis is determined by the value of effective magnetic field). Asymptotic energy dependences (with respect to d, H, P) are determined analytically. As the momentum P increases, the exciton spectrum in a weak fixed H crosses over from Coulombic to magnetic, and for large P consists of bands adjacent to the Landau levels. Also discussed is the problem of an electron spatially separated from a charged impurity in coupled quantum wells. Fiz. Tekh. Poluprovodn. 32, 1354–1362 (November 1998)