‎we call a ring $r$ right generalized semiperfect if every simple right $r$-module is an epimorphic image of a flat right $r$-module with small kernel‎, ‎that is‎, ‎every simple right $r$-module has a flat $b$-cover‎. ‎we give some properties of such rings along with examples‎. ‎we introduce flat strong covers as flat covers which are also flat $b$-covers and give characterizations of $a$-perfe...

A new class of time-symmetric solutions to the initial value constraints of vacuum General Relativity is introduced. These data are globally regular, asymptotically flat (with possibly several asymptotic ends) and in general have no isometries, but a U (1) × U (1) group of conformal isometries. After decomposing the Lichnerowicz conformal factor in a double Fourier series on the group orbits, t...

Using a near-field scanning optical microscope (NSOM), crystals of zinc-porphyrin network materials are characterized with respect to morphology and fluorescence. Needle-shaped crystals are observed. While the topography is flat, the fluorescence intensity profile in the width direction is approximately triangular. A numerical calculation shows that differences between the topographic and optic...

In the past few years secure messaging has become mainstream, with over a billion active users of end-to-end encryption protocols through apps such as WhatsApp, Signal, Facebook Messenger, Google Allo, Wire and many more. While these users’ two-party communications now enjoy very strong security guarantees, it turns out that many of these apps provide, without notifying the users, a weaker prop...

The tensile strength estimated from the Brazilian test on brittle materials is highly dependent contact topology between sample and loading platens. Common topologies such as flat-to-point, arch-to-arch flat-to-flat contacts have been proposed in literature. By employing cohesive interface elements (CIEs), a finite element method (FEM) developed this paper to explore fracture behaviour of sampl...

We propose a new training based scheme for multiple antenna broadcast channels consisting of a base station (transmitter) and many users (receivers) in a flat fading environment. Both the transmitter and the users transmit at a common carrier frequency so that, by virtue of reciprocity, the downlink and uplink propagation matrices are equal. We show that by using appropriate training the base s...

0020-7683/$ see front matter 2013 Elsevier Ltd. A http://dx.doi.org/10.1016/j.ijsolstr.2013.03.018 ⇑ Corresponding authors. Tel.: +1 608 346 7275 (L. Don E-mail addresses: [email protected] (L. (R. Lakes). High structural damping combined with high stiffness is achieved by negative stiffness elements. Negative incremental structural stiffness occurs when a column with flat ends is subjecte...

We find complete expanding Kähler-Ricci solitons of two types. The first are cohomogeneity one under the action (2m - 1)-dimensional Heisenberg group or a certain quotient it, for any m ? 2. second type, which generalizes first, reside on ?*-bundles over compact Kähler Ricci-flat manifolds, admit an S1 by isometries, and have ends. Both types local structure stemming from ansatz described in [2...

In this paper we study the homotopical rotation vectors and the homotopical rotation sets for the billiard flow on the unit flat torus with three, mutually intersecting and mutually orthogonal cylindrical scatterers removed from it. The natural habitat for these objects is the infinite cone erected upon the Cantor set Ends(F3) of all “ends” of the hyperbolic group F3 = π1(Q). An element of Ends...

Molecular Dynamics simulations of a coarse-grained bead-spring model of flexible macromolecules tethered with one end to the surface of a cylindrical pore are presented. Chain length N and grafting density σ are varied over a wide range and the crossover from “mushroom” to “brush” behavior is studied for three pore diameters. The monomer density profile and the distribution of the free chain en...