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Numerical simulation of the transient multiphase field during plasma deposition manufacturing composite materials

science china(Physics,{2. & Astronomy) 2009年第4期52卷 508-517页

作者： KONG FanRong1,2.ZHANG HaiOu1 & WANG GuiLan3.1 State Key Laboratory of Digital Manufacturing Equipment and technology,huazhong university of science and technology,Wuhan {2.,china 2.Research Center for Advanced Manufacturing,Southern Methodist university,3.01 Dyer Street,Dallas,Texas 752.5,USA 3.College of Material science and Engineering,huazhong university of science and technology,Wuhan {2.,china State Key Laboratory of Digital Manufacturing Equipment and technology Huazhong University of Science and Technology Wuhan China Research Center for Advanced Manufacturing Southern Methodist University Dallas USA College of Material science and Engineering Huazhong University of Science and Technology Wuhan China

A solid/liquid/gas unified model has been developed to investigate the gradient composition formation during the plasma deposition manufacturing(PDM) composite materials process. In this model,an enthalpy porosity model was applied to deal with the melting and solidification of the deposited layer,and a level-set approach was introduced to track the evolution of the free surface of the molten pool and the deposited layer. Moreover,complicated physical phenomena occurring at the liquid/gas interface,including forced convection heat loss,heat emission and plasma heat source,have been incorporated into the governing equations by source terms. In this study,the numerical experiment of nickel base alloy powder deposited on the medium steel substrate by PDM technique was implemented based on the staggered grid and SIMPLEC algorithm. Concentration gradient distribution of the solute material at the composite material interface,fluid flow and temperature distribution in the molten pool and the deposited layer have been investigated in detail.

关键词： plasma deposition manufacturing composite material solid/liquid/gas unified model level-set approach

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A complex variable meshless method for fracture problems

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science china(Physics,{2. & Astronomy) 2006年第1期49卷 46-59页

作者： CHENG Yumin1 & LI Jiuhong2.1. Shanghai Institute of Applied Mathematics and mechanics, Shanghai university, Shanghai 2.0072. {2. 2. department of Building Engineering, Xi’an university of technology, Xi’an 710048, {2. Shanghai Institute of Applied Mathematics and mechanics Shanghai University Shanghai China department of Building Engineering Xi’an University of Technology Xi’an China

Based on the moving least-square (MLS) approximation, the complex variable moving least-square approximation (CVMLS) is discussed in this paper. The complex variable moving least-square approximation cannot form ill-conditioned equations, and has greater precision and computational efficiency. Using the analytical solution near the tip of a crack, the trial functions in the complex variable moving least-square approxi- mation are extended, and the corresponding approximation function is obtained. And from the minimum potential energy principle, a complex variable meshless method for fracture problems is presented, and the formulae of the complex variable meshless method are obtained. The complex variable meshless method in this paper has greater precision and computational efficiency than the conventional meshless method. Some examples are given.

关键词： moving least-square approximation, complex variable moving least-square approximation, meshless method, complex variable meshless method, fracture.

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A SEMI-ANALYTICAL AND SEMI-NUMERICAL METHOD FOR SOLVING 2.D SOUND-STRUCTURE INTERACTION PROBLEMS

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Acta Mechanica Solida Sinica 2003年第2期16卷 116-126页

作者： Xiang Yu Huang Yuying (College of Civil Engineering and mechanics,huazhong university of science and technology,Wuhan {2.,{3.) Coll. of Civ. Eng. and mechanics Huazhong Univ. of Sci./Technology Wuhan 430074 China

Based on the transfer matrix method and the virtual source simulation technique, this paper proposes a novel semi-analytical and semi-numerical method for solving 2.D sound- structure interaction problems under a harmonic *** any integration segment, as long as its length is small enough,along the circumferential curvilinear coordinate,the non- homogeneous matrix differential equation of an elastic ring of complex geometrical shape can be rewritten in terms of the homogeneous one by the method of extended homogeneous capacity proposed in this *** the exterior fluid domain,the multi-circular virtual source simulation technique is *** source density distributed on each virtual circular curve may be ex- panded as the Fourier's *** with the inverse fast Fourier transformation,a higher accuracy and efficiency method for solving 2.D exterior Helmholtz's problems is presented in this *** the aspect of solution to the coupling equations,the state vectors of elastic ring induced by the given harmonic excitation and generalized forces of coefficients of the Fourier series can be obtained respectively by using a high precision integration scheme combined with the method of extended homogeneous capacity put forward in this *** to the superposition princi- ple and compatibility conditions at the interface between the elastic ring and fluid,the algebraic equation of system can be directly constructed by using the least square *** of acoustic radiation from two typical fluid-loaded elastic rings under a harmonic concentrated force are *** results show that the method proposed is more efficient than the mixed FE-BE method in common use.

关键词： sound-structure interaction acoustic radiatlon multi-circular virtual source simulation technique transfer matrix method inverse fast Fourier transformation semi-analytical and semi-numerical method

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The optimization of DNA encodings based on GA/SA algorithms

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Progress in Natural science:Materials International 2007年第6期17卷 739-744页

作者： Wang Wei1, Zheng Xuedong2. Zhang Qiang1 and Xu Jin2.1. Liaoning Key Laboratory of Intelligent Information Processing, Dalian university, Dalian 11662., china 2. {2. of Control science and Engineering, huazhong university of science and technology, Wuhan 43.074, china) Liaoning Key Laboratory of Intelligent Information Processing Dalian University Dalian 116622 China department of Control science and Engineering Huazhong University of Science and Technology Wuhan 430074 China

The design of DNA sequence plays an important role in improving the reliability of DNA computation. Proper constrained terms that DNA sequence should satisfy are selected, and then the evaluation formulas of each DNA individual corresponding to the selected constrained terms are proposed. The heuristic improved genetic algorithm (GA)/simulated annealing (SA) algorithm is presented to solve the multi-objective optimize problem, and the DNA sequence design system is developed. Furthermore, an example is illustrated to show the efficiency of our method given here.

关键词： DNA encoding multi-objective optimize GA/SA algorithms

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THE COMPLEX VARIABLE BOUNDARY ELEMENT METHOD FOR SOLVING SANDWICH PLATE PROBLEMS

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Acta Mechanica Sinica 1990年第1期6卷 50-58页

作者： Gu Lei Huang Maokuang, department of Modern mechanics, {2. of {3. and technology of china department of Modern mechanics University of Science and Technology of China China

The objective of this paper is to develop a new complex variable boundary element method for sand- wich plates of Reissner's type and Hoff's type. The general solution of Helmhotz equation in complex field is given. Based on the Vekua's complex integral representation of the analytic function, the new boundary integral equations are formulated. The density function in the integral equation is determined directly by boundary element method. Some standard examples are presented, and the results of numerical solutions are accurate everywhere in the plate. The approach presented is only applicable for bounded simply connected regions.

关键词： BEM sandwich plates Helmhotz equation

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Effects of NaNbO_3.Co_2._3.Co-additive on the Properties of PZN-PZT Ceramics

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Journal of Wuhan university of technology(Materials {2.) 2007年第4期22卷 722-724页

作者：邓毅华 College of Material science and Engineering South China University of Technology department of Electronic science and {2. Huazhong University of Science and TechnologyWuhan 430074China

NaNbO3.Co2.3.co-added PZN-PZT （PZCNNT） ceramics were prepared using conventional solid state reaction. The piezoelectric and dielectric properties were measured. The experimental results show that the addition of 0.3.o1% Co2.3.leads to low dielectric loss （tgδ） in PZCNNT ceramics and the proper addition of NaNbO3.not only improves piezoelectric properties but also decreases intensively dielectric loss and mechanical loss. The optimal ceramic having d3.=3.0 pC/N, kp=0.59, εr=985, tgδ=0.003., Qm=13.0 was obtained.

关键词： PZN-PZT piezoelectric constant dielectric constant dielectric loss

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s-ordering operator expansions of quantum-mechanical fundamental representations and their applications

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science china(Physics,{2. & Astronomy) 2011年第12期54卷 2150-2154页

作者： FAN HongYi 1,3., XU YeJun 2.& YUAN HongChun 3.4 1 department of Materials science and Engineering, {2. of science and technology of china, Hefei 2.002., china 2.department of Physics Electronic and Engineering, Chizhou {2., Chizhou 2.7000, china 3.department of Physics, Shanghai Jiao Tong {2., Shanghai 2.003., china 4 College of Optoelectronic Engineering, Changzhou Institute of technology, Changzhou 2.3.02. china department of Materials science and Engineering University of Science and Technology of China Hefei China department of Physics Shanghai Jiao Tong University Shanghai China department of Physics Electronic and Engineering Chizhou University Chizhou China College of Optoelectronic Engineering Changzhou Institute of Technology Changzhou China

We show that the quantum-mechanical fundamental representations, say, the coordinate representation, the coherent state representation, the Fan-Klauder entangled state representation can be recast into s-ordering operator expansion, which is elegant in form and has many applications in deriving new operator identities. This demonstrates that Dirac's symbolic method can be merged into Newton-Leibniz integration theory in a broad way.

关键词： s-ordering operator expansion operator identities quantum mechanical representation

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PEM:a lightweight program memory encryption mechanism for embedded processor

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The Journal of china Universities of Posts and Telecommunications 2010年第1期17卷 77-84页

作者： HUO Wen-jie,LIU Zheng-lin,ZOU Xue-cheng department of Electronics of science and {2.,{3.,Wuhan 43.074,china department of Electronics of science and {2. Huazhong University of Science and Technology Wuhan 430074 China

Application of embedded systems is faced with multiple threats against security. To solve this problem, this article proposes a new program memory encryption mechanism （PEM） to enhance the security of embedded processor. The new mechanism encrypts all the programs via a secure cache structure. It not only caches the instructions read from the off-chip memory, but also stores the pad values used to encrypt the plaintext. It effectively accelerates encryption and reduces the performance overhead. Besides the encryption, PEM also monitors the program modifications and reset behaviors to reduce the risk of vicious tamper. The experiment indicates that PEM has an average of 2.3.% performance improvement and results in a 2..71% power reduction in the write-back stage. The new scheme offers a good balance between performance and security. It is fully practicable for embedded processor.

关键词： embedded processor memory encryption advanced encryption standard (AES) secure cache hardware protection

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The influence of thermal radiation on MHD station-point flow past a stretching sheet with heat generation

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Acta Mechanica Sinica 2011年第4期27卷 502-509页

作者： Jing Zhu.Lian-Cun Zheng.Xin-Xin Zhang department of Mathematics and mechanics,{2. of {3. and technology Beijing,100083.Beijing,china Thermal Engineering department,{2. of {3. and technology Beijing,100083.Beijing,china Zheng department of Mathematics and mechanics University of Science and Technology Beijing Beijing China Thermal Engineering department University of Science and Technology Beijing Beijing China

This letter is concerned with the plane and axisymmetric stagnation-point flows and heat transfer of an electrically-conducting fluid past a stretching sheet in the presence of the thermal radiation and heat generation or absorption. The analytical solutions for the velocity distribution and dimensionless temperature profiles are obtained for the various values of the ratio of free stream velocity and stretching velocity, heat source parameter, Prandtl number, thermal radiation parameter, the suction and injection velocity parameter and magnetic parameter and dimensionality index in the series form with the help of homotopy analysis method （HAM）. Convergence of the series is explicitly dis- cussed. In addition, shear stress and heat flux at the surface are calculated.

关键词： Thermal radiation MHD Laminar boundarylayers - Homotopy analysis method

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Measurements and analysis of force and moment of caudal fin model in C-start

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Progress in Natural science:Materials International 2006年第8期16卷 796-802页

作者： ZHAO Liang, JING Jun, LU Xiyun and YIN Xiezhen (department of Modern mechanics, {2. of {3. and technology of china, Hefei 2.002., china) department of Modem mechanics University of Science and Technology of China Hefei 230027 China

The unsteady hydrodynamic forces and moments acting on caudal-fin models of fish with different shapes and different swing durations were experimentally measured to simulate the fish C-starts. The motion of models was characterized by rotating the model to a maximum deflection angle in an excursion time Tu and back to the initial position in a return time Td around its root-axis. Studies show that the caudal-fin plays an important role in fish C-starts and the caudal-fins with different shapes and different swing durations generate different forces and moments. In addition, the hydrodynamic forces and moments acting on the models with different shapes can be normalized by the 2.d and 3.d moments of area, respectively. The forces and moments acting on the models with different swing durations, but the same ratio of Tu to Td can also be scaled.

关键词： C-start model test measurement of unsteady force and moment caudal-fin shape swing duration normalized coefficient scaling coefficient.

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