检索结果-南通市图书馆

ELASTO-PLASTICITY ANALYSIS BASED ON COLLOCATION WITH THE MOVING LEAST SQUARE METHOD

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2003年第2期16卷 162-170页

作者： Song Kangzu Zhang Xiong Lu Mingwan (Department of Engineering Mechanics,Tsinghua university,beijing 100084.China) Department of Engineering Mechanics Tsinghua University Beijing 100084 China

A meshless approach based on the moving least square method is developed for elasto-plasticity analysis,in which the incremental formulation is *** this approach,the dis- placement shape functions are constructed by using the moving least square approximation,and the discrete governing equations for elasto-plastic material are constructed with the direct collo- cation *** boundary conditions are also imposed by *** method established is a truly meshless one,as it does not need any mesh,either for the purpose of interpolation of the solution variables,or for the purpose of construction of the discrete *** is simply formu- lated and very efficient,and no post-processing procedure is required to compute the derivatives of the unknown variables,since the solution from this method based on the moving least square approximation is already smooth *** examples are given to verify the accuracy of the meshless method proposed for elasto-plasticity analysis.

关键词： meshless method elasto-plasticity collocation method moving least square incremental formulation

TWO-DIMENSIONAL SIMULATION OF FLOWS IN PLANE-WALL DIFFUSERS

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1992年第4期4卷 43-53页

作者： Yuan Ming-shun Department of Hydraulic Engineering,Tsinghua university,beijing 100084.P.R.China

A numerical model has been developed for computing turbulent flow in plane-wall *** model solves the weakly compressible flow equations with the application of the Smagorinsky's subgrid-scale turbulence model and the boundary conditions of partial slip and no slip at the solid *** examples include two-dimensional calculations of unstalled and stalled flows in diffusers of small diverging angle,as well as transitory stall flow in a symmetric diffuser of 16°total *** the unstalled and stalled flows,the calculated pressure recovery and velocity profile are compared with experimental *** the transitory stall flow,the com- putational result shows the unsteady flow features including the vortex shedding and stall washout phenomena that have been experimentally observed.

关键词： diffuser turbulent flow separation transitory stall Large-eddy simulation

THE EXISTENCE OF RADIAL LIMITS OF ANALYTIC FUNCTIONS IN BANACH SPACES

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2001年第4期22卷 513-518页

作者： BU SHANGQUAN Department of Applied Mathematics, Tsinghua university, beijing 100084. China. E-mail: sbu@*** Department of Applied Mathematics Tsinghua University Beijing 100084 China

Let X be a complex Banach space without the analytic Radon-Nikodym property. The author shows that G = {f∈H∞(D,X) there exists∈＞ 0, such that for almost allθ∈[0, 2], lim sup f(reiθ) - f(seiθ)≥∈ } is a dense open subset of H∞(D, X). It is also shown that for every open subset B of T, there exists F∈H∞ (D, X), such that F has boundary values everywhere on Bc and F has radial limits nowhere on B. When A is a measurable subset of T with positive measure, there exists f∈H∞ (D, X), such that f has nontangential limits almost everywhere on Ac and f has radial limits almost nowhere on A.

关键词： Analytic Radon-Nikodym property Radial limits and vector-valued Hardy space

The Villin/Gelsolin/Fragmin Superfamily Proteins in Plants

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2007年第8期49卷 1183-1191页

作者： Hui Su Ting Wang Huaijian Dong Haiyun Ren (Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Sciences beijing Normal university beijing 100875 China Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Sciences Beijing Normal University Beijing 100875 China

The villin/gelsolin/fragmin superfamily is a conserved Ca^2＋-dependent family of actin-regulating proteins that is widely present both in mammalian and non-mammalian organisms. They have traditionally been characterized by the same core of three or six tandem gelsolin subdomains. The study in vertebrates and lower eukaryotic cells has revealed that the villin/gelsolin/fragmin superfamily of proteins has versatile functions including severing, capping, nucleating or bundling actin filaments. In plants, encouraging progress has been made in this field of research in recent years. This review will summarize the identified plant homologs of villin/gelsolin/fragmin superfamily, thus providing a basis for reflection on their biochemical activities and functions in plants.

关键词： actin-binding protein actin cytoskeleton Villin/Gelsolin/Fragmin.

INFLUENCE　OF　CYCLE　PHASE　TRANSFORMATION　ON　TEXTURE　AND　YIELD　STRESS　ANISOTROPY　IN　TITANIUM　SHEET

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 1994年第4期4卷 72-77页

作者： Zhu, Zhishou Gu,Jialin Chen, Nanping (Department of Materials Science and Engineering,Tsinghua university,beijing 100084.

ＩＮＦＬＵＥＮＣＥＯＦＣＹＣＬＥＰＨＡＳＥＴＲＡＮＳＦＯＲＭＡＴＩＯＮＯＮＴＥＸＴＵＲＥＡＮＤＹＩＥＬＤＳＴＲＥＳＳＡＮＩＳＯＴＲＯＰＹＩＮＴＩＴＡＮＩＵＭＳＨＥＥＴ￥Ｚｈｕ，Ｚｈｉｓｈｏｕ；Ｇｕ，Ｊｉａｌｉｎ；Ｃｈ... 详细信息

ＩＮＦＬＵＥＮＣＥＯＦＣＹＣＬＥＰＨＡＳＥＴＲＡＮＳＦＯＲＭＡＴＩＯＮＯＮＴＥＸＴＵＲＥＡＮＤＹＩＥＬＤＳＴＲＥＳＳＡＮＩＳＯＴＲＯＰＹＩＮＴＩＴＡＮＩＵＭＳＨＥＥＴ￥Ｚｈｕ，Ｚｈｉｓｈｏｕ；Ｇｕ，Ｊｉａｌｉｎ；Ｃｈｅｎ，Ｎａｎｐｉｎｇ（Ｄｅｐａｒｔ...

关键词： cycle phase transformation texture crystallite orientation distribution function titanium

Toward path reliability by using adaptive multi-path routing mechanism for multimedia service in mobile Ad-hoc network

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2010年第1期17卷 93-100页

作者： ZHEN Yan,WU Mu-qing,WU Da-peng,ZHANG Qin-juan,XU Chun-xiu Broadband Communication Network Laboratory,beijing university of Posts and Telecommunications,beijing 100876,China Broadband Communication Network Laboratory Beijing University of Posts and Telecommunications Beijing 100876 China

Traditional multi-path routing mechanisms aim to establish complete node or link disjoint paths. However, under some circumstances if multiple paths cannot be established based on the current network topology, the traditional multi-path routing mechanism will degenerate into single path routing mechanism, thus the advantages of multi-path routing cannot be exhibited. To enhance the end-to-end path reliability, an adaptive multi-path routing mechanism with path segment is proposed, in which multi-path can be established at part of the end-to-end path. In this way the reliability of the path can be enhanced. This path segment mechanism can divide the end-to-end path into several short segments, and a parallel forwarding mechanism is proposed for guaranteeing the quality of service of multimedia services over the wireless network. Simulations show that the network performance metrics such as the packet delivery ratio, the end-to-end delay and the number of route discoveries are all improved by using the adaptive multi-path routing mechanism.

关键词： mobile Ad-hoc networks multi-path routing reliability parallel forwarding path segment

The role of the catalysts with highly dispersed and isolated active sites in the selective oxidation of light hydrocarbons

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第12期15卷 1066-1072页

作者： WANG Hongxuan and ZHAO Zhen State Key Laboratory of Heavy Oil Processing,China university of Petroleum,beijing 10224.,China State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing 102249 China

This review summarizes the role of catalysts with highly dispersed and isolated active sites (active sites:supported atoms f≤0.5 %) in the selective oxidation of light hydrocarbons,such as methane,ethane and propane,into oxygenates and the epoxidation of *** plausible structures of the highly dispersed and isolated active species,as well as their effects on the catalytic performances are *** special physico-chemical properties and the functional mechanism of the catalysts with highly dispersed and isolated active sites,as well as the preparation,characterization of the catalysts with highly dispersed and isolated active sites and their applications in other types of reactions of lower hydrocarbons are summarized.

关键词： selective oxidation light hydrocarbons highly dispersed isolated active sites oxygenates catalyst methane ethane propane

Mapping and overlapping based carrier frequency searching technique for rapid GNSS long PN-code acquisition

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2010年第12期53卷 2642-2652页

作者： LI Hong ,LU MingQuan & FENG ZhenMing Department of Electronic Engineering,Tsinghua university,beijing 100084.China Department of Electronic Engineering Tsinghua University Beijing China

In global navigation satellite systems(GNSS),because of the long period and high chip rate of long pseudo-noise(PN) code,the rapid acquisition is hard to *** speed up search process,in the paper,a mapping and overlapping based carrier frequency searching technique is *** mapping incoming signals of the same interval to different carrier frequency cells and overlapping together the mapped incoming signals that correspond to the same code phase,the technique reduces the number of the cells to be *** effect of the technique on detection and mean acquisition time performance is *** is shown that the technique reduces the cells to be searched and shortens mean acquisition time at the expense of degrading detection *** technique is fit to the previously published acquisition methods and is capable of improving their mean acquisition time *** and simulation results validate the analysis.

关键词： carrier frequency cells mapping overlapping acquisition performance

A Besov Estimate for Multilinear Singular Integrals

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2000年第4期16卷 613-626页

作者： Wengu Chen Department of Mathematics, Capital Normal university. beijing 10003.. P. R. China Department of Mathematics Capital Normal University Beijing 100037 P. R. China

The main pnrpose of this paper is to prove a good λ inequality for a multilinear singular integral in R^n.

关键词： Multilinear operator Besov space Good λ inequality