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Complex Function Approximation Based on Multi-ANN Approach

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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.

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

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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

AN INVESTIGATION ON COMPUTER-CONTROLLED TURNING AND CONTOUR DESIGNING OF SHAPED CONNECTION

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Chinese Journal of Mechanical Engineering 2000年第4期13卷 278-284页

作者： He xiaojiaDing Chongsheng He Yue (School of Mechanical Engineering, xi’an jiaotong university) 西安交通大学陕西西安

The computer-controlled turning technique of shaped connection (keyless connection), shaft and hole, is discussed. By using the method, a clearance free fit with a taper is obtained. After the comparison of the mechanical behavior and the turning machinability of the contours, it is found that the present contour needs further improvement, and a new contour is presented.

关键词： Shaped connection Profiling turning Computer-controlled machining

Effects　of　strength　matching　and　crack　depth　on　the　fracture　parameters　for　welded　joints

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China Welding 1994年第1期3卷 35-44页

作者： Tang Wei and Shi Yaowu (xi’an jiaotong university)

Fracture parameters of welded joints with different strength matching and crack depth in weld metal are investigated by using the methods of elastoplastic finite element analysis and three point bend specimen test. The results show that for shallow crack, the plastic zone turns large in loading process, and the fracture toughness turns high. The extent of the plastic zone of overmatched joint is larger than that of undermatched joint because it will extends to parent metal from the weld metal in loading process for the same CTOD value. The plastic zone of undermatched joint is restricted within the weld, and the size of that is small. Overmatched joint shows the fracture behaviour of shallow crack may more easily than the undermatched joint, while the two sorts of joint specimens have the same crack depth. Therefore, the fracture-resistant capability of overmatched weld is better than that of undermatched weld. when the toughness of weld metals is similar for both overmatched and undermatched joints.

关键词： welded joint fracture parameter plastic zone crack depth strength matching

APPLICATION OF WAVELET TRANSFORM IN STRUCTURAL OPTIMIZATION

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Chinese Journal of Mechanical Engineering 2001年第3期14卷 231-236页

作者： Lin Hui,Zhang Youyun (Theory of Lubrication and Bearing Institute ,xi’ an jiaotong university) 西安交通大学轴承研究所陕西

It is very common in structural optimization that the optima lie at or in the vicinities of the singular points of feasible domain. Therefore it is very reasonable to introduce wavelet transform that is advantageous in singularity detection. The principle and algorithm of the application of wavelet transform in structural optimization are discussed The feasibility is demonstrated by some typical examples.

关键词： Wavelet transform Structural optimization Singularity

ON SPINODAL BOUNDARIES OF Al-Li ALLOYS

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Acta Metallurgica Sinica(English Letters) 1995年第1期8卷 41-46页

作者： WEI Yinghui WANG xiaotian (School of Materials Scince and Engineering xi’an jiaotong university xi’an 710049 China ) xi'an jiaotong Univ Xi'an China

The spinodal decomposition can occur in Al-Li alloys containing 5.8-14.2 at.% Li at room temperature. The modutated structure wavelength is approximately 3.1 nm for com mercial Al-LI alloys. The limit composition of t... 详细信息

关键词： Al-Li alloy spinodal decomposition regular solution

Structural signature and contact force distributions in the simulated three-dimensional sphere packs subjected to uniaxial compression

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Science China(Physics,Mechanics & Astronomy) 2010年第5期53卷 892-904页

作者： LIU LianFeng1,2,ZHANG Lei1 & LIAO ShuFang1 1 Department of Mathematical Sciences,xi’an jiaotong-Liverpool university,Suzhou 215123,China 2 School of Science,xi’an jiaotong university,xi’an 710049,China 1. Department of Mathematical Sciences Xi’an Jiaotong-Liverpool University Suzhou 215123 China2. School of Science Xi’an Jiaotong University Xi’an 710049 China

Packing of spherical particles in a three-dimensional cylindrical container is simulated by using Discrete Element *** packed bed of spheres is also subjected to vertical compression which results in a dense *** of the packing during compaction are examined in detail in terms of the contact number,deviator fabric,and radial distribution ***,contact force distributions are measured at different locations in the pack,*** centre,the side wall,and the base(or bottom wall) of the *** simulations show that random close packing(RCP) tends to exist in the centre of the pack,while ordered packing structures exist near the container's *** uniaxial compression doesn't seem to alter the packing structure in the pack centre remarkably,but to reduce the structural anisotropy of the packing close to the container's *** simulated results have also helped to establish the correlations between packing structures and contact force ***,it is shown that small contact force distributions are sensitive to local packing *** simulated results are shown to be consistent with the recent experimental and simulation findings.

关键词： packing contact force distribution discrete element method particles boundary effect

NONLINEAR GALERKIN METHOD AND CRANK-NICOLSONMETHOD FOR VISCOUS INCOMPRESSIBLE FLOW

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Journal of Computational Mathematics 1999年第2期17卷 139-158页

作者： Yin-nian He Dong-sheng Li Kai-Tai Li(College of Science, xi’an jiaotong university, xi’an 710019, China) 西安交通大学基础科学部陕西西安

In this article we discuss a new full discrete scheme for the numerical solution of the Navier-Stokes equations modeling viscous incompressible flow. This scheme consists of nonlinear Galerkin method using mixed finite elements and Crank-Nicolson method. Next, we provide the second-order convergence accuracy of numerical solution corresponding to this scheme. Compared with the usual Galerkin scheme, this scheme can save a large amount of computational time under the same convergence accuracy. (Author abstract) 8 Refs.

关键词： nonlinear Galerkin method Crank-Nicolson method viscous incompressible flow

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

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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