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891.
892.
Ming‐Chih Lai 《Numerical Methods for Partial Differential Equations》2004,20(1):72-81
In this article, we extend our previous work 3 for developing some fast Poisson solvers on 2D polar and spherical geometries to an elliptical domain. Instead of solving the equation in an irregular Cartesian geometry, we formulate the equation in elliptical coordinates. The solver relies on representing the solution as a truncated Fourier series, then solving the differential equations of Fourier coefficients by finite difference discretizations. Using a grid by shifting half mesh away from the pole and incorporating the derived numerical boundary value, the difficulty of coordinate singularity can be elevated easily. Unlike the case of 2D disk domain, the present difference equation for each Fourier mode is coupled with its conjugate mode through the numerical boundary value near the pole; thus, those two modes are solved simultaneously. Both second‐ and fourth‐order accurate schemes for Dirichlet and Neumann problems are presented. In particular, the fourth‐order accuracy can be achieved by a three‐point compact stencil which is in contrast to a five‐point long stencil for the disk case. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 72–81, 2004 相似文献
893.
Ronald E. Mickens P. M. Jordan 《Numerical Methods for Partial Differential Equations》2004,20(5):639-649
A positivity‐preserving nonstandard finite difference scheme is constructed to solve an initial‐boundary value problem involving heat transfer described by the Maxwell‐Cattaneo thermal conduction law, i.e., a modified form of the classical Fourier flux relation. The resulting heat transport equation is the damped wave equation, a PDE of hyperbolic type. In addition, exact analytical solutions are given, special cases are mentioned, and it is noted that the positivity condition is equivalent to the usual linear stability criteria. Finally, solution profiles are plotted and possible extensions to a delayed diffusion equation and nonlinear reaction‐diffusion systems are discussed. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004. 相似文献
894.
Using the constructions of the preceding two papers, we construct a natural transformation (after inverting 2) from the Browder-Novikov-Sullivan-Wall
surgery exact sequence of a compact manifold to a certain exact sequence of C
*-algebra K-theory groups.
Mathematics Subject Classification (1991): 19J25, 19K99 相似文献
895.
We develop the theory of analytically controlled Poincaré complexes over C
*-algebras. We associate a signature in C
*-algebra K-theory to such a complex, and we show that it is invariant under bordism and homotopy.
The authors were supported in part by NSF Grant DMS-0100464. 相似文献
896.
We consider propositional dynamic logic for agents. For this logic, we present a sequent calculus with a restricted cut rule and prove the soundness and completeness for the calculus. 相似文献
897.
Let K
m,nbe a complete bipartite graph with two partite sets having m and n vertices, respectively. A K
p,q-factorization of K
m,n is a set of edge-disjoint K
p,q-factors of K
m,n which partition the set of edges of K
m,n. When p = 1 and q is a prime number, Wang, in his paper “On K
1,k
-factorizations of a complete bipartite graph” (Discrete Math, 1994, 126: 359—364), investigated the K
1,q
-factorization of K
m,nand gave a sufficient condition for such a factorization to exist. In the paper “K
1,k
-factorizations of complete bipartite graphs” (Discrete Math, 2002, 259: 301—306), Du and Wang extended Wang’s result to the
case that q is any positive integer. In this paper, we give a sufficient condition for K
m,n to have a K
p,q-factorization. As a special case, it is shown that the Martin’s BAC conjecture is true when p : q = k : (k+ 1) for any positive integer k. 相似文献
898.
899.
船舶进出宁波港分道通航方案 总被引:1,自引:1,他引:0
近年来,宁波港吞吐量猛增,并有继续上升趋势,而大型船舶进出港口仅用虾峙门的单向航道,与宁波港口发展不相适应。提出二套船舶进出口方案,与现有的虾峙门航道构成分道通航制,供港口主管部门进行航道规划参考。 相似文献
900.
黄河三角洲盐生草甸白茅(Imperata cylindrica var. major)群落季节性动态的研究 总被引:1,自引:0,他引:1
采用定位研究的方法研究了生长季白茅(Imperata cylidrica var. major)群落的主要特征和动态。群落的种类组成较简单,其盖度一般在七月中旬达到100%。群落的高增长及地上生产量符合逻辑斯蒂增长模型(Logistic model),并主要受环境中水分和温度因子的影响。群落的最大高度为59cm,出现在八月中旬;地上生产量最大值为干重563g/m~2,出现在九月中旬。 相似文献