Temperature dependence of79BrNQR frequency in cadmium strontium,barium, zinc,magnesium and nickel bromates

The⁷⁹Br quadrupole resonance in cadmium, strontium, barium, zinc, magnesium and nickel bromates is studied in the range 77 to 305 K. The temperature dependence of the resonance frequencies in these systems has been analysed on the basis of the torsional motion of the BrO ₃ ⁻ groups. The torsional frequency and its temperature behaviour have been analysed.     

High Temperature Expansion for a Driven Bilayer System

Based directly on the microscopic lattice dynamics, a simple high temperature expansion can be devised for non-equilibrium steady states. We apply this technique to investigate the disordered phase and the phase diagram for a driven bilayer lattice gas at half filling. Our approximation captures the phases first observed in simulations, provides estimates for the transition lines, and allows us to compute signature observables of non-equilibrium dynamics, namely, particle and energy currents. Its focus on non-universal quantities offers a useful analytic complement to field-theoretic approaches.     

有限二维复式晶格电子结构的尺度效应

以二维复式晶格作为有限系统的集团模型,利用紧束缚近似,在考虑链间耦合及链端效应的情况下,计算了格点数分别为16、32、64、128时π电子在最近邻及次近邻跳跃集团的能谱和态密度.讨论了不同格点数和结构参数对态密度及带宽的影响.     

Inverse semigroups determined by their lattices of convex inverse subsemigroups I

Every inverse semigroup possesses a natural partial order and therefore convexity with respect to this order is of interest. We study the extent to which an inverse semigroup is determined by its lattice of convex inverse subsemigroups; that is, if the lattices of two inverse semigroups are isomorphic, how are the semigroups related? We solve this problem completely for semilattices and for inverse semigroups in general reduce it to the case where the lattice isomorphism induces an isomorphism between the semilattices of idempotents of the semigroups. For many inverse semigroups, such as the monogenic ones, this case is the only one that can occur. In Part II, a study of the reduced case enables us to prove that many inverse semigroups, such as the free ones, are strictly determined by their lattices of convex inverse subsemigroups, and to show that the answer obtained here for semilattices can be extended to a broad class of inverse semigroups, including all finite, aperiodic ones. Received September 24, 2002; accepted in final form December 15, 2002.     

Parallel Supercomputing PC Cluster and Some Physical Results in Lattice QCD

We describe the construction of a high performance parallel computer composed of PC components, presentsome physical results for light hadron and hybrid meson masses from lattice QCD. We also show that the smearingtechnique is very useful for improving the spectrum calculations.     

SEMIGROUPS CHARACTERIZED BY THEIR FUZZY IDEALS

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Coproducts of bounded distributive lattices: infinite distributivity

Summary It is shown that, if two bounded distributive lattices satisfy the join-infinite distributive law (JID), then their coproduct also satisfies this law. In 1986, Yaqub proved that generalized Post algebras with a finite lattice of constants satisfy JID, and stated that, in general, it is not known whether a generalized Post algebra satisfies JID when its lattice of constants satisfies JID. In this note, the statement is proved.     

Capacities with Values in Compact Hausdorff Lattices

For a compact Hausdorff topological lattice L the set M _L X of L-valued normed regular capacities on a compact Hausdorff topological space X is investigated. It is shown that the set M _L X carries a compact Hausdorff topology, and M _L extends to a weakly τ-normal functor in the category of compacta. If L is an upper and lower Lawson semilattice, then M _L is the functorial part of two semimonads. These semimonads coincide and are a monad if and only if L is distributive, i.e., is a Lawson lattice. The obtained results have a natural interpretation if capacities are regarded as subjective estimates of likelihood of realization of events in conditions of uncertainty.      

Refinement of Vahlen's Theorem for Minkowski Bases of Three-Dimensional Lattices

In the paper, the analog of Vahlen's theorem for Minkowski bases of three-dimensional lattices is sharpened.     

Comparative study of lattice‐Boltzmann and finite volume methods for the simulation of laminar flow through a 4:1 planar contraction

In the present paper, a comparative study of numerical solutions for Newtonian fluids based on the lattice‐Boltzmann method (LBM) and the classical finite volume method (FVM) is presented for the laminar flow through a 4:1 planar contraction at a Reynolds number of value one, Re=1. In this study, the stress field for LBM is directly obtained from the distribution function. The calculations of the stress based on the FVM‐data use the evaluations of velocity gradients with finite differences. The stress field for both LBM and FVM is expressed in the present study in terms of the shear stress and the first normal stress difference. The lateral and axial profiles of the velocity, the shear stress and the first normal stress difference for both methods are investigated. It is shown that the LBM results for the velocity and the stresses are in excellent agreement with the FVM results. Copyright © 2004 John Wiley & Sons, Ltd.