检索结果-南通市图书馆

SIDEBANDS OF X-RAY DIFFRACTION IN AGE-HARDENED Cu-Ti ALLOY

在线全文

同方期刊数据库

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 1996年第4期6卷 87-93页

作者： Wei Yinghui Wang xiaotian(School of Materials Science and Engineering,xi’an Jiaotong University,xi’an 710049) xiAN JIAOTONG UNIV SCH MAT SCI & ENGNXIAN 710049PEOPLES R CHINA

ＳＩＤＥＢＡＮＤＳＯＦＸ－ＲＡＹＤＩＦＦＲＡＣＴＩＯＮＩＮＡＧＥ－ＨＡＲＤＥＮＥＤＣｕ－ＴｉＡＬＬＯＹ￥ＷｅｉＹｉｎｇｈｕｉ；ＷａｎｇＸｉａｏｔｉａｎ（ＳｃｈｏｏｌｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎ... 详细信息

ＳＩＤＥＢＡＮＤＳＯＦＸ－ＲＡＹＤＩＦＦＲＡＣＴＩＯＮＩＮＡＧＥ－ＨＡＲＤＥＮＥＤＣｕ－ＴｉＡＬＬＯＹ￥ＷｅｉＹｉｎｇｈｕｉ；ＷａｎｇＸｉａｏｔｉａｎ（ＳｃｈｏｏｌｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅｒｉｎｇ，Ｘｉ＇ａｎＪｉａｏｔ...

关键词： Cu-Ti alloy X-ray diffraction sidebands static lattice wave theory

Investigation of the crack problem in non-local piezoelectric materials under combined electromechanical loadings

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2009年第2期25卷 219-225页

作者： Q. Li Y. Chen School of Aerospace, xi’an Jiao-Tong University,710049 xi’an, China School of Aerospace Xi’an Jiao-Tong University 710049 Xi’an China

The present investigation of the crack problem in piezoelectric materials is performed based on the non-local theory. After some manipulations, the impermeable crack, the permeable crack （the crack gap is full of NaCI solution）, and the semi-permeable crack （the crack gap is full of air or silicon oil） are reduced to a uniform formulation by assuming the normal electric displacement on the crack surfaces to be an unknown variable. Thus, a triple integral equation with the unknown normal electric displacement is established. By using the Newton iterative method and solving the triple integral equation, it is found that the normal electric displacement on the crack surfaces is no longer a constant as determined by previous studies, rather, it depends upon the remote combined electromechanical loadings. Numerical results of the stresses and electric displacement fields show that there are no singularities at the crack tips so that the stresses remain finite. It is of great significance that the concrete electric boundary condition on the crack surfaces exerts significant influence on the near-tip fields and in this way plays an important role in evaluating the crack stability in the non-local piezoelectric materials. More specifically, the impermeable crack model always overestimates the finite stresses at the crack tips, whereas the permeable crack model always underestimates them.

关键词： Crack Non-local piezoelectric materialsImpermeable Permeable Semi-permeable

Complex Function Approximation Based on Multi-ANN Approach

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 1995年第2期6卷 22-31页

作者： Li Renhou & Gao Feng (Institute of Systems Engineering, xi’an Jiaotong University, xi’an 710049, China) Institute of Systems Engineering Xi'an Jiaotong University Xi'an 710049 China

This paper presents a multi-ANN approximation approach to approximate complex non-linear function. Comparing with single-ANN methods the proposed approach improves and increases the approximation and generalization ability, and adaptability greatly in learning processes of networks. The simulation results have been shown that the method can be applied to the modeling and identification of complex dynamic control systems.

关键词： Backpropagation algorithm Multilayer perception Complex function approximation Input space partitioning.

The study of adsorption gas sensor based carbon nanotube film

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2005年第4期48卷 372-384页

作者： LI xin1, LIU Junhua2 & ZHU Changchun1 1. School of Electronic and Information Engineering, xi’an Jiaotong University, xi’an 710049, China 2. School of Electric Engineering, xi’an Jiaotong University, xi’an 710049, China 1. School of Electronic and Information Engineering Xi’an Jiaotong University 710049 Xi’an China 2. School of Electric Engineering Xi’an Jiaotong University 710049 Xi’an China

The study of gas sensitivity of multi-wall carbon nanotubes (MWNTs), which is deposited by low press chemical vapor deposition (LPCVD), is presented. The results show that the pure MWNTs are not sensitive to the gases measured, while the composite film consisting of the MWNTs and silicon dioxide is sensitive to the methane, the hydrogen and the acetylene. The MWNTs and silicon dioxide composite film have the capacitance characteristic because of the formation of Schottky junctions within the MWNTs. The chemistry adsorption of the gas measured on the surface of the MWNTs affects the space discharge area of the Schottky junction, so that the dielectric constant changes with the gas concentration. That is why the gas is sensed.

关键词： gas sensor, carbon nanotubes, low press chemical vapor deposition, scatter.

ANALYSIS OF CRACK-TIP SINGULARITIES FOR AN INTERFACIAL PERMEABLE CRACK IN METAL/PIEZOELECTRIC BIMATERIALS

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2007年第3期20卷 247-257页

作者： Li Qun Chen Yiheng~* (School of Aerospace,xi’an Jiao-Tong University,xi’an 710049,China) School of Aerospace Xi''an Jiao-Tong University Xi''an 710049 China

By modeling metal as a special piezoelectric material with extremely small piezoelec- tricity and extremely large permittivity,we have obtained the analytical solutions for an interfacial permeable crack in metal/piezoelectric bimaterials by means of the generalized Stroh formalism. The analysis shows that the stress fields near a permeable interfacial crack tip are usually with three types of singularities:r;and r;.Further numerical calculation on the oscillatory indexεare given for 28 types of metal/piezoelectric bimaterials combined by seven commercial piezoelectric materials: PZT-4,BaTiO;,PZT-5H,PZT-6B,PZT-7A,P-7 and PZT-PIC 151 and four metals:copper,silver,lead and aluminum,*** explicit expressions of the crack tip energy release rate（ERR）and the crack tip generalized stress intensity factors（GSIF）are *** is found that both the ERR and GSIF are independent of the electric displacement loading,although they seriously depends on the mechanical loadings.

关键词： interfacial permeable crack metal/piezoelectric bimaterials energy release rate intensity factor

ExiSTENCE AND UNIQUENESS OF STRONG PERIODIC SOLUTION OF THE EVOLUTION SYSTEM DESCRIBING GEOPHYSICAL FLOW-PART I: IN BOUNDED DOMAINS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2001年第3期22卷 385-396页

作者： ZHAO CHUNSHAN, LI KAITAI School of Science, xi’an Jiaotong University, xi’an 710049, China. School of Science Xi'an Jiaotang University Xi'an 710049 China

The existence and uniqueness of a strong periodic solution of the evolution system describing geophysical flow in bounded domains of RN (N = 3, 4) are proven if external forces are periodic in time and sufficiently sm... 详细信息

关键词： Existence and uniqueness Periodic solution Evolution system Geophysical flow

Part-based on-road vehicle detection using hidden random field

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2011年第12期54卷 2542-2549页

作者： ZHANG XueTao 1 , HE YongJian 1,2 & WANG Fei 1 1 Institute of Artificial Intelligence and Robotics, xi’an Jiaotong University, xi’an 710049, China 2 xi’an Communication Institute, xi’an 710049, China 1. Institute of Artificial Intelligence and Robotics Xi’an Jiaotong University Xi’an 710049 China2. Xi’an Communication Institute Xi’an 710049 China

This paper addresses the problem of detecting on-road vehicles in still images captured by the on-board cameras. We model this as a labelling inference procedure and incorporate the part-based representation of the rear-ends of vehicle within a hidden random field based probabilistic model. Representing objects with parts inherently good for dealing with occlusions. In the proposed model, the part labels form a hidden layer in the graphical model. Our approaches can automatically find the latent parts without explicit indication during training. The experiment is performed on the database with real images with a promising result.

关键词： vehicle detection hidden random field part-based model

FINITE ELEMENT NONLINEAR GALERKIN COUPLINGMETHOD FOR THE EXTERIOR STEADY NAVIER-STOKESPROBLEM

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 1999年第6期17卷 595-608页

作者： Yin-nian He Kai-tai Li Fu-hai Gao(College of Science, xi’an Jiaotong University, xi’an 710049, China) xian Jiao Tong Univ Coll Sci Xian 710049 Peoples R China

In this paper we represent a new numerical method for solving the steady Navier-Stokes equations in three dimensional unbounded domain. The method consists in coupling the boundary integral and the finite element nonlinear Galerkin methods. An artificial smooth boundary is introduced seperating an interior inhomogeneous region from an exterior one. The Navier-Stokes equations in the exterior region are approximated by the Oseen equations and the approximate solution is represented by an integral equation over the artificial boundary. Moreover, a finite element nonlinear Galerkin method is used to approximate the resulting variational problem. Finally, the existence and error estimates are derived.

关键词： Navier-Stokes equations Oseen equations boundary integral finite element nonlinear Galerkin method

Particle Image Velocimetry Measurement of Flow Across Tube Bundle in Waste Heat Boiler

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2000年第3期9卷 249-256页

作者： Chen Bin Guo Liejin (xi’an Jiaotong University, xi’an 710049, China ) xi’an Jiaotong University Xi’an China

In the present paper the experimental investigations of flow across staggered tube bundles in waste heat boiler are conducted by mans of PIV (Particle Image Velocimetry) system. Flow visualization and velocity distribution of the wake between different cylinders are measured in detail. It is concluded that there are still Von Karman vortices in the wake and the phenomena of vortex shedding, pairing, merging are observed in the flow. The Von Karman vortices can’t fully developed because of the existence of the downstream cylinder There is interaction between main streams and vortices, and the development of the vortex is enhanced by this interaction. Meanwhile some statistical results are performed. The distribution of correlated variables of the velocity fluctuations u’ u’, u’ v’, v’ v’ and the space correlation coefficients are obtained.

关键词： tube bundle flow across cylinder turbulent wake.