Supraleitung des Galliums bei hohem Druck

A high-pressure modification of Gallium was formed at liquid helium temperature by the application of a pressure in excess of 35000 atm. It was superconducting with a transition temperature of 6·38°K. The high-pressure form remained after the pressure was removed at helium temperature. This resulted, however in a shift in transition temperature to 7·5°K. The average derivativedT _c/dp was ?3·10^?5°K/atm.     

Minimal subtraction and the decoupling of heavy quarks for arbitrary values of the gauge parameter

The decoupling of a heavy quark is investigated to two loops for QCD renormalized by minimal subtraction. It is shown that the heavy quark effects can be absorbed into an effective coupling constant, an effective gauge parameter and effective masses for the light quarks. The relations between these effective parameters and the parameters of the full theory are gauge invariant. In terms of the effective parameters the theory satisfies renormalization group equations which refer only to the light degrees of freedom.     

Kinetic-catalytic determination of vanadium in non-aqueous solvents

Determination of trace vanadium in organic solvents is studied by use of the oxidation of o-dianisdine with t-butyl hydroperoxide. The sensitivity of the catalyzed reaction is optimized by application of a modified simplex method. Under optimum conditions the detection limit is 0.7 ng V ml^?1 in acetonitrile and the relative standard deviation is 0.048. The effect of other metal ions and of co-solvents is discussed. The method is used for trace determinations of vanadium in organic solvents of high purity.     

Zur Asymptotik der wellengleichung und der wärmeleitungsgleichung in zweidimensionalen außenräumen

We study initial and boundary value problems for the wave equation and the heat equation with a time-independent right-hand term f in two space dimensions in the exterior of a closed curve C. In the case of Neumann's boundary condition ?u/?n = 0 on C, the solutions increase with a logarithmic rate as t → ∞ if ∫ fdx ≠ 0. In contrast to this, the solutions of the corresponding Dirichlet problems converge to the solution of the related static problem as t → ∞. In the case of the wave equation, these results have already been obtained by L: A. Muravei under the additional assumption that the curvature of C is positive, by using high frequency estimates for the reduced wave equation Δ U + ?² U = 0. The analysis presented here is based on different methods, which can be applied to arbitrary smooth curves.     

Untersuchungen an quaternären Fluoriden LiMeIIMeIIIF6 Die Struktur von LiCaAlF6

LiCaAlF₆ crystallizes trigonal (lattice constants a = 4.996, c = 9.636 Å; Z = 2, space group P3 1c) in a structure which is derived from the Li₂ZrF₆ type. Refinement by least squares yielded R = 0.073.