Temperature dependence of the order parameter and of diffuse scattering in the Hg<Subscript>2</Subscript>Cl<Subscript>2</Subscript> model ferroelastics

The fundamental and diffuse x-ray reflections from Brillouin zone-edge X points of the paraelastic phase of Hg₂Cl₂ crystals (whose integrated intensity is related to the order parameter and its fluctuations) were studied. Information was obtained on the temperature dependence of the order parameter and of diffuse scattering, and the critical exponents were determined. The conclusion is drawn that the ferroelastic phase transition in these crystals is close to the tricritical point.     

Quark-antiquark composite systems: The Bethe-Salpeter equation in the spectral-integration technique

The Bethe-Salpeter equations for the quark-antiquark composite systems, q\(\bar q\), are written in terms of spectral integrals. For the q\(\bar q\) mesons characterized by the mass M, spin J, and radial quantum number n, the equations are presented for the following (n, M²) trajectories: π _J , η _J , a _J , f _J , ρ _J , ω _J , h _J , and b _J .     

Black multi‐crystalline silicon solar cells

A simple method for nano‐scale texturing of silicon surfaces based on local metal‐catalyzed wet chemical etching, which results in an almost complete suppression of reflectivity in a broad spectral range, has been successfully applied to produce black multi‐crystalline silicon solar cells. The performance of the cells is compared to that of reference cells without surface nano‐texturing. A considerable increase of the short circuit current (by 36–42% with respect to the reference cells) without deterioration of other performance parameters is observed under natural sun illumination. Means of further optimization of such black solar cells are discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Concentrated solutions for internal wave equations

We consider the propagation of internal gravity waves in a stratified fluid layer with a current. Formal asymptotic solutions concentrated in the horizontal plane are constructed for the linearized system of equations in the Boussinesq approximation. The complex space-time ray method is used.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 148, pp. 120–132, 1985.     

Gauge invariance of the Landau nonlinear damping decrement of Bose excitations in a quark-gluon plasma: Part II

The physical mechanisms determining the nonlinear scattering of plasmons on particles of a quark-gluon plasma are analyzed. The connection between the Landau nonlinear damping decrement of longitudinal oscillations and the damping decrement derived from the hard-temperature loop approximation is investigated. The part of the decrement that depends on the gauge parameter on the mass shell is shown to be equal to zero. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 124, No. 2, pp. 292–309, August, 2000.