On the one-electron theory of crystalline solids in a homogeneous electric field

Assuming that the one-electron states of a perfect crystalline solid are known, an approach for the calculation of the one-electron states in the presence of external fields and/or other deviations from the periodic potential of the perfect crystal is suggested. The treatment is based on the Wannier representation and the use of a method for solving some operator non-polynomial differential equations. In the approximation of the one-band Wannier equation an exact solution of the problem for electron states of the crystals in a homogeneous external electric field is given. The results obtained in the tight binding approximation for cubic crystals show that the electron motion along the field is finite and the degree of its finiteness for a given electric field strength is greater, the smaller the width of the initial energy band considered. In the one-band approximation Considered the electron energy spectrum has the character of the Wannier-Stark ladder. It is also shown that an influence of transverse motion on the character of the finite motion along the field appears when a non-additivity in the initial energy band function with respect to the energies of motions parallel and perpendicular to the field direction is present.     

Omega- and Omega+ production in central Pb + Pb collisions at 40 and 158A GeV

Results are presented on Omega production in central Pb+Pb collisions at 40 and 158A GeV beam energy. For the first time in heavy ion reactions, rapidity distributions and total yields were measured for the sum Omega(-) + Omega(+) at 40A GeV and for Omega(-) and Omega(+) separately at 158A GeV. The yields are strongly underpredicted by the string-hadronic UrQMD model but agree better with predictions from hadron gas models.     

Anion adsorption induced reversal of coherency strain

Experimental results are presented for stress evolution, in vacuum and electrolyte, for the first monolayer of Cu on Au(111). In electrolyte the monolayer is pseudomorphic and the stress-thickness change is -0.60 N/m, while conventional epitaxy theory predicts a value of +7.76 N/m. In vacuum, the monolayer is incoherent with the underlying gold. Using a combination of first-principles based calculations and molecular dynamic simulations we analyzed these results and demonstrate that in electrolyte, overlayer coherency is maintained owing to anion adsorption.     

Asymptotics of zeros of polynomials arising from rational integrals

We prove that the zeros of the polynomials Pm(a) of degree m, defined by Boros and Moll via

     

Gaussian extended cubature formulae for polyharmonic functions

The purpose of this paper is to show certain links between univariate interpolation by algebraic polynomials and the representation of polyharmonic functions. This allows us to construct cubature formulae for multivariate functions having highest order of precision with respect to the class of polyharmonic functions. We obtain a Gauss type cubature formula that uses values of linear functionals (integrals over hyperspheres) and is exact for all -harmonic functions, and consequently, for all algebraic polynomials of variables of degree .

     

On the structure of weight modules

Given any simple Lie superalgebra , we investigate the structure of an arbitrary simple weight -module. We introduce two invariants of simple weight modules: the shadow and the small Weyl group. Generalizing results of Fernando and Futorny we show that any simple module is obtained by parabolic induction from a cuspidal module of a Levi subsuperalgebra. Then we classify the cuspidal Levi subsuperalgebras of all simple classical Lie superalgebras and of the Lie superalgebra W. Most of them are simply Levi subalgebras of , in which case the classification of all finite cuspidal representations has recently been carried out by one of us (Mathieu). Our results reduce the classification of the finite simple weight modules over all classical simple Lie superalgebras to classifying the finite cuspidal modules over certain Lie superalgebras which we list explicitly.

     

Reversible unfolding of poplar iso-plastocyanins

We attempted to determine the experimental conditions under which poplar plastocyanin iso-forms PCa and PCb undergo reversible thermal unfolding studied by differential scanning calorimetry (DSC). Our results indicate that an exothermic unfolding process exists always in the presence of molecular oxygen. Reversible unfolding and almost perfect two-state transitions were exhibited in the presence of TCEP under anaerobic conditions. This suggests that the second endothermic peak is due to copper-site disulfide dimmers formed during thermal denaturation. The conformational thermal stability of reduced PCb (ΔG (25 °C) = 33.9 kJ mol⁻¹) has proven to be higher than that of reduced PCa (ΔG(25 °C) = 22.9 kJ mol⁻¹).     

On the methodology of Mössbauer spectroscopy with67Zn

Conclusions The piezoceramic vibrators have the advantages of simplicity and stability of operation over those with quartz plates. However, the former show mechanical hysteresis causing distortions of the motion. This effect can be reduced by an appropriate choice of the ceramic cylinder, but it is not completely avoidable. That is why these distortions should be taken into account or quartz vibrators should be used in precision measurements. The displacement piezoceramic sensor described here gives new methodological opportunities in assembling and preliminary testing of the vibrators to find the optimum of construction and operating conditions as well as for continuous motion control during spectrum accumulation and eventual corrections of the motion distortions.