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Comparison of the Molecular Interaction Volume Model with the Unified Interaction Parameter Formalism in the Fe-Cr-Ni Liquid Alloys at 1873 K

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Journal of materials science & Technology 2006年第4期22卷 559-564页

作者： Dongping TAO faculty of materials and Metallurgical engineering, Kunming university of science and Technology, Kunming 650093, china faculty of materials and Metallurgical engineering Kunming University of Science and Technology Kunming 650093 China

The molecular interaction volume model (MIVM) for a general ternary system was deduced in detail for further clarifying and understanding its general multicomponent expression. Both MIVM and the unified interaction parameter formalism (UIPF) can be used to predict the activities of solutes and solvents in the Fe-Cr-Ni liquid alloys. But the former employs only the infinite dilute activity coefficients, and the later is not applicable without the dilute binary and ternary interaction parameters. MIVM has a certain physical meaning from the viewpoint of statistical thermodynamics, so it is an alternative for the estimation of activity coefficients of the solutes and solvents in a dilute or finite concentration metal solution where the interaction parameters are absent or their accuracies are questionable.

关键词： Activity Prediction Molecular interaction volume model Unified interaction parameter formalism

Blank design optimization for stepped-section profile ring rolling

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science china(Technological sciences) 2010年第6期53卷 1612-1619页

作者： QIAN DongSheng & HUA Lin School of materials science and engineering,wuhan university of Technology,wuhan 430070,china School of materials science and engineering Wuhan University of Technology

A stepped-section ring consists of two rectangular section rings,a big ring and a small ring,joined *** kind of ring is difficult to process by the ring rolling technique because of its complex cross-sectional *** a reasonable blank design is *** this paper,four blank designs,one is a rectangular cross-section and the other three are stepped-sections with different step volumes,are proposed and compared with each other using theoretical analysis,FE simulation and *** is shown that three of the designs can lead to volume flow from small ring into big ring during rolling,which is disadvantageous for shape formation and dimensional precision;however,the other design may result in good ring shape and high dimensional ***,the optimal blank design is determined to be the one in which the volumes of the big and small rings of the initial blank are equal to those of the final rings,respectively.

关键词： ring rolling stepped-section ring optimization design FE simulation

Hochschild cohomology of special biserial algebras

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science china Mathematics 2007年第8期50卷 1117-1128页

作者： Yun-ge XU faculty of Mathematics & Computer science,hubei university,wuhan 4.0062,china faculty of Mathematics & Computer science Hubei University Wuhan China

Based on a four-term exact sequence,the formulae on the dimensions of the first and the second Hochschild cohomology groups of special biserial algebras with normed bases are obtained in terms of combinatorics.

关键词： special biserial algebra Hochschild cohomology medal 16E40 16G10

Development of Mathematical Model on Preparation of Functionally Graded Material by Co-sedimentation

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Journal of materials science & Technology 2001年第2期17卷 275-277页

作者： Zhongmin YANG, Lianmeng ZHANG and Qiang SHEN Institute of materials science and engineering, wuhan university of Technology, wuhan 430070, china Inst. of Mat. Sci. Wuhan Univ. of Technol. Wuhan 430070 China

From the process of sedimentation the mathematical relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mathematical model was set up and simulated through the computer. At last the validity of mathematical model was supported by the representative experiment on Ti-Mo system FGM prepared by co-sedimentation.

关键词： Co Mo Development of Mathematical Model on Preparation of Functionally Graded Material by Co-sedimentation

Robust H-infinity fuzzy control for uncertain Markovian jump nonlinear singular systems with wiener process

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控制理论与应用（英文版） 2010年第2期8卷 205-210页

作者： Aiqing ZHANG 1 , Huajing FANG 2 (1.College of Mathematics and Computer science, Jianghan university, wuhan hubei 430056, china 2.Department of Control science and engineering, Huazhong university of science and Technology, wuhan hubei 430074, china) College of Mathematics and Computer science Jianghan University Wuhan Hubei China Department of Control science and engineering Huazhong University of Science and Technology Wuhan Hubei China

This paper deals with the problems of robust stochastic stabilization and H-infinity control for Markovian jump nonlinear singular systems with Wiener process via a fuzzy-control approach. The Takagi-Sugeno (T-S) fuzzy model is employed to represent a nonlinear singular system. The purpose of the robust stochastic stabilization problem is to design a state feedback fuzzy controller such that the closed-loop fuzzy system is robustly stochastically stable for all admissible uncertainties. In the robust H-infinity control problem, in addition to the stochastic stability requirement, a prescribed performance is required to be achieved. Linear matrix inequality (LMI) sufficient conditions are developed to solve these problems, respectively. The expressions of desired state feedback fuzzy controllers are given. Finally, a numerical simulation is given to illustrate the effectiveness of the proposed method.

关键词： Fuzzy control H-infinity control Singular systems Stochastic stability Linear matrix inequality (LMI)

INFLUENCE OF SURFACE HARDENING ON CONTACT FATIGUE LIFE OF NODULAR CAST IRON

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Acta Metallurgica Sinica(English Letters) 1990年第3期3卷 188-193页

作者： TAO Zengyi LUO Jiaming Huazhong university of science and Technology,wuhan,china TAO Zengyi,faculty of Metallic materials,Dept.of Mechanical engineering No.2,Huazhong university of science and Technology,wuhan 430074,china

The influence of laser surface melting and induction hardening on the surface structure,con- tact fatigue life and failure behaviour of the nodular cast iron has been *** con- tact fatigue life can be improved by both laser treatment and induction hardening,but the fail- ure process and type are different from each *** former is due to lumpy and deep spal- ling caused by crack propagation between the quenching zone and the substrate,and the latter is due to nubby and surface flaking caused by the oil wedged action into surface cracks.

关键词： surface hardening contact fatigue life laser melting induction hardening

The characteristics of arc beam shaping in hybrid plasma and laser deposition manufacturing

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science china(Technological sciences) 2006年第2期49卷 238-247页

作者： ZHANG Hai’ou1, QIAN Yingping1,3, WANG Guilan1 & ZHENG Qiguang2 1. School of Material science and Technology, Huazhong university of science and Technology, wuhan 430074, china 2. Institute of Laser Technology and engineering, Huazhong university of science and Technology, wuhan 430074, china 3. Mechanical engineering College, hubei university of Technology, wuhan 430068, china School of Material science and Technology Huazhong University of Science and Technology

As a new direct metal prototyping technology,the hybrid plasma and laser deposition manufacturing (PLDM) is proposed in this paper. In order to figure out the characteristics of plasma arc beam and mould in the PLDM process of high temperature alloy, the high speed CCD camera is used to obtain the picture around the plasma arc. Afterwards the sketch of picture is clearly obtained. And the effect of laser parameter, such as average power, pulse width, pulse repetition frequency and the angle between laser beam and plasma arc beam on the plasma arc appearance, is studied experimentally. The results show that the modality of plasma arc beam is markedly influenced by laser beam. And the improvements of shape precision and surface state of the layer deposited by PLDM are confirmed.

关键词： plasma hybrid laser, direct deposition, plasma arc beam, molding character, high-temperature alloy.

Synthesis and photoluminescence property of red phosphors LiEu_(1-x)Y_x(WO_4)_(0.5)(MoO_4)_(1.5) for white LED

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science china(Technological sciences) 2009年第7期52卷 1913-1918页

作者： XIE An, YUAN XiMing, WANG JuanJuan & WANG Feng engineering Research Center of Nano-Mineral materials and Application, Ministry of Education, faculty of materials science and Chemical engineering, china university of Geosciences, wuhan 430074, china engineering Research Center of Nano-Mineral materials and Application Ministry of Education Faculty of Materials Science and Chemical Engineering China University of Geosciences

A series of novel red phosphors LiEu1-xYx(WO4)0.5(MoO4)1.5 (x=0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8) were synthesized by conventional solid state reaction method with the starting materials: WO3, MoO3, Eu2O3, Li2CO3 and Y2O3. The spectrum and the crystal structure of the phosphors were characterized by F-4500 and XRD respectively. Meanwhile the effects of flux and Y3+ concentration on the crystal structure and luminescent properties of the phosphors were investigated. The results showed that the optimal content of flux (WAlF3/WH3BO3=1/1) was 1 wt% and the optimal doping concentration of Y3+ was 0.5 mol. The emission spectrum showed the most intense peak was located at 615 nm, which corresponds to the 5D0→7F2 transition of Eu3+ and that Eu3+ occupied the lattice site of noncentrosymmetric environment in the scheelite phases. The excitation spectrum displayed that these phosphors could be effectively excited by ultraviolet (UV) (396 nm) and blue (466 nm) light, nicely in correspondence with the widely ap- plied output wavelengths of ultraviolet or blue LED chips. The influence of flux on the luminescent properties of LiEu0.5Y0.5(WO4)0.5(MoO4)1.5 phosphor was analyzed. The XRD spectra indicated that the flux could help to crystallize the phosphor, and no other phases were formed except the tetragonal. When adding flux, the relative intensity of LiEu0.5Y0.5(WO4)0.5(MoO4)1.5 became much stronger and the average particle size of the phosphor decreased.

关键词： red emitting phosphor LiEu1-xYx(WO4)0.5(MoO4)1.5 flux white LED

Surface Nanocrystallization of Magnesium Alloy AZ91D by High-Energy Shot Peening

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Journal of wuhan university of Technology(materials science) 2009年第4期24卷 515-519页

作者：张津 School of materials science & engineering University of Science and Technology Beijing College of materials science & engineering Chongqing University of Technology

High-energy shot peening （HESP）, a method to produce severe plastic deformation by high velocity flying balls, was applied on die cast magnesium alloy AZ91D. Effects of surface nanocrystallization by HESP and heat treatment at different temperatures were investigated. The mi- crostructure evolution was conducted using X-ray diffraction （XRD） and field emission scanning electronic microscopy （FESEM）. The hardness was measured by microhardness tester. The experimental results show that surface nanocrystrallization of AZ91D obtained by HESP would lead to the increase of microhardness. Low temperature heated at 100℃ for 1 h do not change the property obviously. However, both the microstructure and microhardness vary greatly after heat treatment at 400℃ for 1 h.

关键词： AZ91 D surface nanocrystallization HESP microhardnss corrosion resistance