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排序方式: 共有1118条查询结果,搜索用时 140 毫秒
1.
The paper presents a new formulation of the integral boundary element method (BEM) using subdomain technique. A continuous approximation of the function and the function derivative in the direction normal to the boundary element (further ‘normal flux’) is introduced for solving the general form of a parabolic diffusion‐convective equation. Double nodes for normal flux approximation are used. The gradient continuity is required at the interior subdomain corners where compatibility and equilibrium interface conditions are prescribed. The obtained system matrix with more equations than unknowns is solved using the fast iterative linear least squares based solver. The robustness and stability of the developed formulation is shown on the cases of a backward‐facing step flow and a square‐driven cavity flow up to the Reynolds number value 50 000. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
2.
基础房价的相关指标及其走势一直是大众关心的热门话题.本文通过对上海基础房价相关指标的分析,建立了市场房价走势的两个数学模型.模型一:在相关性分析的基础上利用主成分分析消除指标间的共线性,再用回归拟合房价模型并进行预测;模型二:在相关性分析的基础上利用核估计方法预测出房价.继呵对2005年下半年的房价走势进行了预测,得出的结果与实际情况相吻合. 相似文献
3.
Chen Hao 《中国科学A辑(英文版)》2006,49(5):715-720
In this paper, for the the primes p such that 3 is a divisor of p − 1, we prove a result which reduces the computation of the linear complexity of a sequence over GF(p
m) (any positive integer m) with the period 3n (n and p
m − 1 are coprime) to the computation of the linear complexities of three sequences with the period n. Combined with some known algorithms such as generalized Games-Chan algorithm, Berlekamp-Massey algorithm and Xiao-Wei-Lam-Imamura
algorithm, we can determine the linear complexity of any sequence over GF(p
m) with the period 3n (n and p
m
− 1 are coprime) more efficiently. 相似文献
4.
HypersurfacewithConstantMainCurvatureSymmetricFunctions¥WuBaoqiang;SongHongzao(XuzhouTeachersCollege,221009)(HenanUniversity,... 相似文献
5.
测定了室温下烃类(乙炔、乙烷)烟粒的红外复折射率,并讨论了所获数据在测量烟浓度与烟粒大小分类、计算光谱吸收系数及在特定浓度与温度下评估烟雾辐射率方面的应用。 相似文献
6.
7.
Modelling a complex geometry, such as ice roughness, plays a key role for the computational flow analysis over rough surfaces. This paper presents two enhancement ideas in modelling roughness geometry for local flow analysis over an aerodynamic surface. The first enhancement is use of the leading‐edge region of an airfoil as a perturbation to the parabola surface. The reasons for using a parabola as the base geometry are: it resembles the airfoil leading edge in the vicinity of its apex and it allows the use of a lower apparent Reynolds number. The second enhancement makes use of the Fourier analysis for modelling complex ice roughness on the leading edge of airfoils. This method of modelling provides an analytical expression, which describes the roughness geometry and the corresponding derivatives. The factors affecting the performance of the Fourier analysis were also investigated. It was shown that the number of sine–cosine terms and the number of control points are of importance. Finally, these enhancements are incorporated into an automated grid generation method over the airfoil ice accretion surface. The validations for both enhancements demonstrate that they can improve the current capability of grid generation and computational flow field analysis around airfoils with ice roughness. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
8.
A fourth‐order compact finite difference scheme on the nine‐point 2D stencil is formulated for solving the steady‐state Navier–Stokes/Boussinesq equations for two‐dimensional, incompressible fluid flow and heat transfer using the stream function–vorticity formulation. The main feature of the new fourth‐order compact scheme is that it allows point‐successive overrelaxation (SOR) or point‐successive underrelaxation iteration for all Rayleigh numbers Ra of physical interest and all Prandtl numbers Pr attempted. Numerical solutions are obtained for the model problem of natural convection in a square cavity with benchmark solutions and compared with some of the accurate results available in the literature. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
9.
Helge Glöckner 《manuscripta mathematica》1998,97(2):205-215
Let G be a p-adic Lie group. Then G is a locally compact, totally disconnected group, to which Willis [14] associates its scale function G : G→ℕ. We show that s can be computed on the Lie algebra level. The image of s consists of powers of p. If G is a linear algebraic group over ℚ
p
, s(x)=s(h) is determined by the semisimple part h of x∈G. For every finite extension K of ℚ
p
, the scale functions of G and H:=G(K) are related by s
H
∣
G
=s
G
[
K
:ℚ
p
]. More generally, we clarify the relations between the scale function of
a p-adic Lie group and the scale functions of its closed subgroups and Hausdorff quotients.
Received: 20 February 1997; Revised version: 18 May 1998 相似文献
10.
原子吸收法在有机分析中的应用(Ⅵ)香烟中氢氰酸的分析 总被引:3,自引:0,他引:3
原子吸收法在有机分析中的应用(Ⅵ)香烟中氢氰酸的分析谢志海,郎惠云,高云(西北大学化学系,西安,710069)关键词:氢氰酸,测定,原子吸收光谱香烟中的尼古丁,烟焦油等含氮有机物燃烧后将产生氢氰酸,吸入人体后极为有害。国外在这方面的研究始于七十年代,... 相似文献