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CONVERGENCE OF AN EXPLICIT UPWIND FINITE ELEMENT METHOD TO MULTI-DIMENSIONAL CONSERVATION LAWS

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Journal of Computational Mathematics 2001年第1期19卷 87-100页

作者： jin-chao Xu Lung-an Ying Center for Computational Mathematics and Applications and Department of Mathematics Pennsylvania State UniversityU.S.A School of Mathematical Sciences Peking UniversityBeijing 100871China

Investigates the convergence of an explicit upwind finite element method, the edge-averaged finite element method to multidimensional scalar conservation laws. Discussion on the finite element scheme and main converge... 详细信息

关键词： conservation law finite element method convergence

Wavelet Neural Network Based on NARMA-L2 Model for Prediction of Thermal Characteristics in a Feed System

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Chinese Journal of Mechanical Engineering 2011年第1期24卷 33-41页

作者： jin chao WU Bo HU Youmin State Key Laboratory for Digital Manufacturing Equipment and Technology Huazhong University of Science and Teehnology Wuhan 430074 China School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China

Research of thermal characteristics has been a key issue in the development of high-speed feed system. Most of the work carried out thus far is based on the principle of directly mapping the thermal error against the temperature of critical machine elements irrespective of the operating conditions. But recent researches show that different sets of operating parameters generated significantly different error values even though the temperature of the machine elements generated was similar. As such, it is important to develop a generic thermal error model which is capable of evaluating the positioning error induced by different operating parameters. This paper ultimately aims at the development of a comprehensive prediction model that can predict the thermal characteristics under different operating conditions （feeding speed, load and preload of ballscrew） in a feed system. A novel wavelet neural network based on feedback linearization autoregressive moving averaging （NARMA-L2） model is introduced to predict the temperature rise of sensitive points and thermal positioning errors considering the different operating conditions as the model inputs. Particle swarm optimization（PSO） algorithm is brought in as the training method. According to ISO230-2 Positioning Accuracy Measurement and ISO230-3 Thermal Effect Evaluation standards, experiments under different operating conditions were carried out on a self-made quasi high-speed feed system experimental bench HUST-FS-001 by using Pt100 as temperature sensor, and the positioning errors were measured by Heidenhain linear grating scale. The experiment results show that the recommended method can be used to predict temperature rise of sensitive points and thermal positioning errors with good accuracy. The work described in this paper lays a solid foundation of thermal error prediction and compensation in a feed system based on varying operating conditions and machine tool characteristics.

关键词： wavelet neural network NARMA-L2 model particle swarm optimization thermal positioning error feed system

Shape Coexistence and Band Termination in Doubly Magic Nucleus ^40Ca

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Communications in Theoretical Physics 2005年第3期43卷 509-514页

作者： DONGBao-Guo GUOHong-chao SHIYi-jin DepartmentofNuclearPhysics ChinaInstituteofAtomicEnergyP.O.Box275（18）Beijing102413China

Shape coexistence and band structure near yrast line of the Z ＝ N doubly magic nucleus 40Ca have been investigated by the configuration-dependent cranked Nilsson-Strutinsky approach. The observed normal deformed and superdeformed bands are explained and the terminating states are confirmed by the calculations. The transition quadrupole moment Qt of the calculated superdeformed band is in good agreement with the observed one at high spin. There is shape coexistence within the same configuration. Possible normal deformed and superdeformed bands with rotation around the intermediate axis in several interesting configurations of40Ca are discussed. Possible favored superdeformed band terminations in 38Ca and 38Ar are predicted. The experimental results in 38Ar are discussed simply.

关键词： shape coexistence configuration-dependent cranked Nilsson-Strutinskyapproach superdeformed band termination transition quadrupole moment

Does strict environmental regulation enhance the global value chains position of China's industrial sector?

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Petroleum Science 2021年第6期18卷 1899-1909页

作者： jin-chao Wang Zhi-Da jin Mian Yang Sameen Naqvi Center for Economic Development Research Wuhan UniversityWuhan430072China Economics and Management School Wuhan UniversityWuhan430072China

Given the vital importance of global value chains(GVCs)position for a country's international competitiveness,this paper tries to investigate the impacts of environmental regulation on the GVCs position of China's industrial *** the latest value-added decomposition method,we first measure the GVCs position of China's industrial sector from 2003 to ***,both two-stage least squares(2 SLS)method with panel data and mediating effect model are employed to empirically examine the effects of environmental regulation on China's position in *** results indicate that environmental regulation has significantly upgraded the GVCs position of China's industrial sector,and the effect is more evident for the sub-sectors with originally lower GVCs *** mediation effect test shows that increasing R&D investment is an important channel through which environmental regulation affects the GVCs position of China's industrial sector,which verifies the existence of the Porter *** analysis finds that the enhancement of GVCs position of China's industrial sector caused by environmental regulation is mainly achieved through reducing the backward GVCs position.

关键词： Environmental regulation Global value chains Porter hypothesis Industrial sector

MODIFIED MORLEY ELEMENT METHOD FOR A FOURTH ORDER ELLIPTIC SINGULAR PERTURBATION PROBLEM

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Journal of Computational Mathematics 2006年第2期24卷 113-120页

作者： Ming Wang jin-chao Xu Yu-cheng Hu LMAM School of Mathematical Science Peking University Beijing 100871 China School of Mathematical Science Peking University Beijing 100871 China and Department of Mathematics Pennsylvania State University USA School of Mathematical Science Peking University Beijing 100871 China

This paper proposes a modified Morley element method for a fourth order elliptic singular perturbation problem. The method also uses Morley element or rectangle Morley element, but linear or bilinear approximation of finite element functions is used in the lower part of the bilinear form. It is shown that the modified method converges uniformly in the perturbation parameter.

关键词： Morley element Singular perturbation problem.

Effects of Airfoil-probe Tubes on the Flow Field of a Compressor Cascade

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Journal of Thermal Science 2017年第4期26卷 321-330页

作者： MA Hongwei jin chao ZHAO Lianpeng MA Rong National Key Laboratory of Science and Technology on Aero-Engines Collaborative Innovation Center of Advanced Aero-EngineSchool of Energy&Power EngineeringBeihang UniversityBeijing100191China

To explore the effects of airfoil-probe tubes and its installment position on the flow field of the compressor cas- cade, and find out the mechanism that how the airfoil-probes affect the aerodynamic characteristics of the com- pressor cascade, this paper performed both numerical and experimcntal works on the same compressor cascade. The experiment mainly focused on the cases of low Mach number （Ma = 0.1）, and cases with different Mach numbers （0.1, 0.3, 0.7） and different incidence angles （-5, 0, 5） are investigated by the numerical method. The case without the airfoil-probe tube was referenced as the baseline, and other three cases with the airfoil-probe tubes installed in different chordwise positions O0%, 50%, 70% of the chord length） were studied. The diameter of the airfoil-probe tube is 3ram, which is configured as 300% amplification of some particular airfoil-probe ac- cording to the geometrical similarity principle. The results show that the airfoil-probe tubes have a negative in- fluenc~ on the flow capacity of the cascade at all investigation points. The separations and the large scale stream- wise vortices that induced by the airfoil-probe tube on the pressure side cause most the losses at the high Mach number. The influence of the airfoil-probe tube on the flow field in the vicinity of the pressure side surface is lo- cal separation at the low Mach number. The airfoil-probe tubes also have a clearly effect on the leakage flow. It decreases the mass flow of the leakage flow and weakens the intensity of the leakage vortex, but enlarges the in- fluence area. The total pressure loss of the case that the tube is installed at the half chordwise position is generally lower than other cases especially at the high Mach number, it can even decrease the losses compared with the ba- sic case.

关键词： airfoil-probe compressor cascade installment position 5-hole probe

A Preconditioned Recycling GMRES Solver for Stochastic Helmholtz Problems

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Communications in Computational Physics 2009年第7期6卷 342-353页

作者： chao jin Xiao-Chuan Cai Cadence Design Systems 555 River Oaks ParkwaySan JoseCA 95134USA Department of Computer Science University of Colorado at BoulderBoulderCO 80309USA

We present a parallel Schwarz type domain decomposition preconditioned recycling Krylov subspace method for the numerical solution of stochastic indefinite elliptic equations with two random ***-Loeve expansions are used to represent the stochastic variables and the stochastic Galerkin method with double orthogonal polynomials is used to derive a sequence of uncoupled deterministic *** show numerically that the Schwarz preconditioned recycling GMRES method is an effective technique for solving the entire family of linear systems and,in particular,the use of recycled Krylov subspaces is the key element of this successful approach.

关键词： Recycling GMRES domain decomposition additive Schwarz preconditioner stochastic Helmholtz equation

Distributed Field Rotator Composed of Isolated Components

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Chinese Physics Letters 2014年第4期31卷 50-53页

作者： LIU Guo-Chang LI chao SHAO jin-jin FANG Guang-You Key Laboratory of Electromagnetic Radiation and Sensing Technology Chinese Academy of Sciences Beijing 100190

Transformation optics offers remarkable control over electromagnetic fields and has recently opened an exciting gateway to design ＇field rotator devices＇. We propose a distributed field rotator with open windows based on composite transformation optics, which consists of a central circular region and several isolated components. The number, position and size of the components can be controlled freely by the design purpose. Full-wave simulations are performed to demonstrate its function, which is equivalent to a classic field rotator. However, such a distributed rotator makes it much easier to access and make use of the rotated field in the central region, compared to the closed classic field rotator, especially in the case of 3D situations.

关键词： ELECTROMAGNETIC fields DIELECTRICS FREE-space optical technology JACOBIAN matrices ELECTROMAGNETISM

Synthesis, Characterization and Cytotoxicity of Ammine/Methylamine Platinum(Ⅱ) Complexes with Carboxylates

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Chemical Research in Chinese Universities 2006年第3期22卷 278-282页

作者： ZHANG jin-chao SHEN Yong YANG Meng-su Department of Chemistry College of Chemistry ＆ Environmental Science Hebei University Baoding 071002 P. R. China Department of Biology and Chemistry City University of Hong Kong Hong Kong P. R. China

Seven novel platinum （Ⅱ） complexes [ Pt（Ⅱ）（NH3）（CH3NH2）X2] （Ⅰ-Ⅶ ）（ X： CH3COO^-, CH2CICOO^- , CHCI2COO^- , C6H5-COO^- , p-CH3O--C6H4-COO^- , p-NH2-C6H4-COO^- , p-NO2--C6H4- COO^-） were prepared and characterized by means of elemental analysis, molar conductivity, thermal analysis, IR, UV, and ^1H NMR spectrometries. The cytotoxicity against HCT-8, BGC-823, MCF-7, EJ, and HL-60 cell lines increases in the following sequence： cisplatin 〉 Ⅳ 〉 Ⅴ 〉 Ⅵ 〉 Ⅶ 〉 Ⅰ 〉 Ⅱ 〉 Ⅲ. Moreover, the complexes （ Ⅰ --Ⅻ） display substantially greater activities agaist EJ and HL-60 cell lines than those against the cell lines from other carcinomas. They can induce a concentration-dependent accumulation of HL-60 cells in the G2/M phase of the cell cycle as cisplatin. There is no significant correlation between total DNA platination levels and cytotoxicity of the complexes.

关键词： Ammine/methylamine platinum(Ⅱ) complex Synthesis Cytotoxicity Cell cycle: DNA-binding