A note on asymptotic homomorphisms

Using the notion of asymptotic homomorphism due to Connes and Higson we construct bivariant homology-cohomology theories for separableC*-algebras, which satisfy general excision axioms and are nonperiodic.     

Austauschreaktionen der Cellulose im wasserfremden Medium

Zusammenfassung Es wird das Verhalten der Kristallviolettbase in absol.-benzol. Lösung gegenüber benzolgequollener Cellulose mit neutralisierten (versalzten bzw. veresterten) COOH-Gruppen unter-sucht.Der Einfluß des Kations auf die Umsetzung wird einer ersten Prüfung unterzogen.Herrn Prof. Dr.A. Zinke zum 70. Geburtstag gewidmet.     

On the Best Constants in Some Non-Commutative Martingale Inequalities

The optimal orders are determined for the best constants inthe non-commutative Burkholder–Gundy, Doob and Stein inequalitiesobtained recently in non-commutative martingale theory. 2000Mathematics Subject Classification 46L53, 46L51.     

Studies on terbium activated yttrium based tantalate phosphors

Terbium activated yttrium niobium tantalate phosphors were prepared by solid-state reaction and were characterized by photoluminescence measurements, X-ray diffraction and scanning electron microscopy. Photoluminescence (PL) of Y_0.95Tb_0.05Ta_1?xNb_xO₄ phosphors (x = 0–1) are influenced by the host-lattice composition, degree of crystalline order and particle morphology and size. The effect of the morpho-structural properties on PL characteristics of Y(Ta,Nb)O₄:Tb powders is reported.     

Layer potentials and boundary value problems for Laplacian in Lipschitz domains with data in quasi-Banach Besov spaces

We study the Dirichlet and Neumann boundary value problems for the Laplacian in a Lipschitz domain ${\Omega}$ , with boundary data in the Besov space ${B_{s}^{p,p} (\partial\Omega).}$ The novelty is to identify a way of measuring smoothness for the solution u that allows us to consider the case p < 1. This is accomplished by using a Besov-based nontangential maximal function in place of the classical one. This builds on the works of Jerison and Kenig [14], where the case p > 1 was treated.     

Occurrence of rotation domains in heteroepitaxy

Heteroepitaxy can involve materials with a misfit of crystal structure. Rotation domains in the epilayer are a fundamental consequence. We derive a general expression for their (minimum) number which is determined by the mismatch of the rotational symmetries of the substrate and epilayer. In the case of a mismatch of rotational symmetry, the number of rotation domains of material A on material B is different from that of B on A. A larger number of rotation domains can occur due to domain structure or nearly fulfilled additional symmetries of the substrate surface.