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Acta Metallurgica Sinica(English letters) 2005年第5期18卷 627-634页

作者： H. Tian j. Wang W.P. Dong j. Chen z. zhao G.M. Wu National Die ＆ Mold CAD Engineering Research Center Shanghai Jiaotong UniversityShanghai 200030 China

Traditionally a rotary forging process is a kind of metal forming method where a conic upper die, whose axis is deviated an angle from the axis of machine, forges a billet continuously and partially to finish the whole deformation. For the rotary forging process simulation, more researches were focused on simulating the simple stage forming process with axisymmetric part geometry. Whereas in this paper, the upper die is not cone-shaped, and the billet is non-axisymmetric. So the movement of the punch is much more complicated than ever. The 3D FEM simulation models for the preforming ＆ final forming processes are set up aider carefully studying the complicated movement pattern. Deform-3D is used to simulate the material flow, and the boundary nodal resisting forces calculated by the final stage process simulation is used to anal.ze the final forming die strength. The CAE analysis of the die shows that the design of the final forming die is not reasonable with lower pre-stress which is easy to crack at the critical corners. An optimum die design is also provided with higher pre-stress, and verified by CAE analysis.

关键词： numerical simulation non-axisymmetric rotary forging die strength

First-principles Study of Point Defects in Stoichiometric and Non-stoichiometric Y_4Al_2O_9

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j.urnal of Materials Science & Technology 2013年第12期29卷 1161-1165页

作者： z.li B.liu j.M.Wang l.C.Sun j.Y.Wang Y.C.zhou z.j.Hu High-performance Ceramics Division Shenyang National Laboratory for Materials ScienceInstitute of Metal ResearchChinese Academy of Sciences Aerospace Research Institute of Materials and Processing Technology

By using the first-principles calculation, we studied the mechanisms of point defects in Y4AI209 （YAM）, a promising ternary oxide with excellent optical and thermal properties. It is found that the predominant native defect species is closely dependent on the chemical potentials of each constituent. In the case of O-rich condition, the oxygen interstitial has the very low defect formation energy, followed by the anti-site defects and AI vacancy; in the case of AI-rich condition, the oxygen vacancy yields the lowest defect formation energy, followed by the anti-site defects and AI interstitial. The present result shows that in all the possible chemical potential ranges, anti-site defects have relatively low defect formation energy and might exist in high concentration in YAM. Furthermore, AIy anti-site has relatively lower defect formation energy than the YAt anti- site throughout. The behaviors of defect complexes under non-stoichiometric condition, such as the AI203 or Y203 excess, are also investigated. The results provide helpful guide to optimize the experimental synthesizing of YAM.

关键词： Ternary Y-AI-O oxide Defect formation energy Chemical potential

Microstructural softening induced adiabatic shear banding in Ti-23Nb-0.7Ta-2zr-O gum metal

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j.urnal of Materials Science & Technology 2020年第19期54卷 31-39页

作者： Silu liu Y.z.Guo z.l.Pan X.z.liao E.j.lavernia Y.T.zhu Q,M,Wei Yonghao zhao Nano and Heterogeneous Materials Center School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Department of Mechanical Engineering University of North Carolina at CharlotteNC 28223-0001USA School of Aerospace Mechanical and Mechatronic EngineeringThe University of SydneyNSW 2006Australia Department of Materials Science and Engineering University of Californi1IrvineCA 92697USA Department of Materials Science and Engineering North Carolina State UniversityNC 27695USA

Ti-23Nb-0.7Ta-2zr-O gum metal(GM)is an attractive candidate material for applications that require superior mechanical *** our earlier investigation of the GM[1],geometrical softening and the generation of adiabatic shear bands(ASBs)were proposed as primary reasons for the documented anisotropic impact *** the present study,electron backscattered diffraction(EBSD)analysis reveals two different deformed microstructures,i.e.,deformed ultrafine grains(UFGs)and dynamically recrystall.zed UFGs,formed in the ASBs of GM samples processed by extrusion equal channel angular pressing(ECAP),*** calculation of temperature rise during dynamic compression suggests that the above microstructure differences in the ASBs was originated from their different maximum ASB temperatures(608 K for extruded GM and 1159 K for ECAP-processed GM).Moreover,our calculation on the temperature at the onset of ASBs indicates that microstructural softening is the primary cause for the development of ASBs in both extruded GM(321 K)and ECAP-processed GM(331 K).

关键词： Gum metal Split hopkinson bar Adiabatic shear band Microstructures

large pore size polyacrylonitrile membrane for ultrafiltration

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j.urnal of Environmental Sciences 2000年第4期12卷 478-481页

作者： Wu, K. Qiu, P. Wang, z. Wang, j. Rsrch. Center for Eco-Envtl. Sci. Chinese Academy of Sciences Beijing 100085 China

The effects of the components of solution for membrane casting and preparation conditions on the membrane performances are studied in this paper. Polyacrylonitrile (PAN) was used as polymer and DMAC as solvent. The ultrafiltration (UF) membranes whose cut-off of molecular weight is 150000 and flux of pure water reaches 150-200 ml/(cm2·h) were prepared by selecting proper components of solution for membrane casting and membrane preparation conditions.

关键词： Casting Molecular weight Polyacrylonitriles Pore size Water quality

MICROWAVE PERMEABIlITY SPECTRA OF SPUTTERED Fe-Co-B SOFT MAGNETIC THIN FIlMS

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Acta Metallurgica Sinica(English letters) 2008年第6期21卷 419-424页

作者： j.S. liao z.K. Feng j. Qiu Y. Q. Tong Department of Electronic Science and Technology Huazhong University of Science and Technology Wuhan 430074 China

Permeability characteristics of sputtered soft magnetic Fe40Co40B20 thin films are investigated in the range of O. 5 to 5 GHz by a shortened microstrip transmission line perturbation method. Excellent microwave permeability is achieved at 0.4 Pa argon pressure： fr is 3.32 GHz, the real and imaginary part of permeability at 0.5 GHz are 104 and 61, respectively. In addition, the thickness effect on permeability is also studied. The minimum damping can be achieved at the thinnest film. Different sources contributed to in-plane anisotropy are discussed briefly. The deviation between the peak frequency of the imaginary part and the zero-crossing frequency of the real part of permeability is also presented.

关键词： Fe-Co-B In-plane anisotropy Magnetic thin films Permeability

An ensemble method for gene discovery based on DNA microarray data

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Science China(life Sciences) 2004年第5期47卷 396-405页

作者： Kathy l. MOSER Eric j. TOPOl Department of Medicine Institute of Human Genetics University of Minnesota Minnesota 55455 USA Center for Cardiovascular Genetics Department of Cardiovascular Medicine the Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 USADepartment of Molecular Cardiology the Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland Ohio 44195 USA

The advent of DNA microarray technology has offered the promise of casting new insights onto deciphering secrets of life by monitoring activities of thousands of genes simulta-neously. Current analyses of microarray data focus on precise classification of biological types, for example, tumor versus normal tissues. A further scientific challenging task is to extract dis-ease-relevant genes from the bewildering amounts of raw data, which is one of the most critical themes in the post-genomic era, but it is generally ignored due to lack of an efficient approach. In this paper, we present a novel ensemble method for gene extraction that can be tailored to fulfill multiple biological tasks including (i) precise classification of biological types; (ii) disease gene mining; and (iii) target-driven gene networking. We also give a numerical application for (i) and (ii) using a public microarrary data set and set aside a separate paper to address (iii).

关键词： microarrays,ensemble decision,recursive partition tree,feature gene selection.

STRUCTURE, MAGNETISM AND MAGNETORESISTANCE OF ANNEAlED Co/Cu DISCONTINUOUS MUlTIlAYERS

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Acta Metallurgica Sinica(English letters) 1997年第6期10卷 465-473页

作者： Yan, S.S. lou, j.X. zhang, l. zhang, R.z. zhang, Y.M. liu, Y.H. Mei, l.M. Huang, j. Shandong Univ Jinan China

Co/Cu discontinuous multilayers were prepared by rf-sputtering method under high sputtering power and then annealed at various temperatures in a high vacuum. The structural, magnetic and transport properties were strongly influenced by the annealing temperature. The annealed samples obviously became discontinuous multilayers. A maximum magnetoresistance ratio of 5.6% was obtained under a relatively low saturation field of about 400 (10/4π) A/m at the optimum annealing temperature of 450°C. When the annealing temperature was increased, the resistivity decreased, and the coercive force and the saturation field increased. The magnetoresistance ratio also depended on the thickness of Co and Cu layers. The magnetic and transport properties were explained on the basis of the discontinuous multilayered structure.

关键词： Copper Magnetic properties Multilayers Sputtering Transport properties

Effect of long-term Thermal Exposure on Microstructure and Stress Rupture Properties of GH3535 Superalloy

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j.urnal of Materials Science & Technology 2015年第3期31卷 269-279页

作者： T.liu j.S.Dong l.Wang z.j.li X.T.zhou l.H.lou j.zhang School of Materials Science and Engineering Dalian University of Technology Institute of Metal Research Chinese Academy of Sciences Shanghai Institute of Applied Physics Chinese Academy of Sciences Shenyang National laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences

The evolution of microstructure and the stress rupture properties of long term thermally exposed GH3535 alloy have been investigated. It was found that M6 C carbides presented in the solid solution heat treated samples. During long term thermal exposure at 700 C, fine M12 C carbides precipitated preferentially at grain boundaries. These carbides coexisted with the pre-exiting M6 C. The stress rupture life of700 C/1000 h exposed sample under creep testing at 650 C/324 MPa is 93 h. It is much longer than that of the solid solution samples. No noticeable changes could be detected in both the microstructure and stress rupture lives when the samples were exposed for time longer than 1000 h M12 C carbides were found to be beneficial to the creep properties. The cracks initiated at the interface of M6 C carbides and matrix, which led to a lower creep rupture life.

关键词： GH3535 superalloy long term thermal exposure Micro

KINETICS OF TEMPER EMBRITTlEMENT IN 2.25Cr-1Mo STEEl USED FOR HOT-WAll HYDROFINING REACTORS

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Acta Metallurgica Sinica(English letters) 2004年第2期17卷 139-146页

作者： j.z.Tan CollegeofMechanicalandPowerEngineering NanjingUniversityofTechnologyNanjing210009China

Based on the theory of grain boundary segregation, a kinetics model of temper em-brittlement caused by long-term service for hot-wall hydrofining reactors was *** kinetics model was applied to phosphorus (P) segregation in 2.25Cr-1Mo steelused for a hot-wall hydrofining reactor, and the kinetics of grain boundary segrea-tion of impurity P in the steel exposed to the process environment of the hydrofiningreactor was calculated on the basis of the model. The Auger electron spectroscopytest was performed in order to determine the grain boundary concentration of P. Theexperimental result is agreement with the theoretical calculated data. The results showthat the kinetics equation is reasonable for predicting the levels of grain boundarysegregation of impurity P in 2.25Cr-1Mo steel used for hot-wall hydrofining reactors.

关键词： hydrofining reactor 2.25Cr-1Mo steel temper embrittlement kinetics

Effects of Growth Temperature on Structural and Electrical Properties of li-N-H Codoped znO

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j.urnal of Materials Science & Technology 2013年第2期29卷 154-156页

作者： Y.F. lu z.z. Ye l.P. zhu Y.j. zeng j.Y. Huang B.H. zhao State Key laboratory of Silicon Materials Department of Materials Science and Engineering Zhejiang University

Effects of growth temperature on the structural and electrical properties of li-N-H codoped znO thin films grown by DC reactive magnetron sputtering were investigated. Scanning electron microscopy and X-ray diffraction results showed that increasing growth temperature could improve the crystalline quality. But Hall measurement results showed that growth temperature had a nonlinear influence on the electrical property. The variation of electrical properties with the growth temperature was found to be related to the activated concentration of N in znO and the evaporation of li during the growth process, derived from the Hall measurement and the second ion mass spectroscopy measurement.

关键词： znO Codoped Growth temperature Structural property Electrical property