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The effects of shock wave and quasi-traveling wave in the mechanical impact test

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Science china(Technological Sciences) 2010年第9期53卷 2535-2541页

作者： WU Mei1,5,SUN ZhongFeng2.ZHANG LuMei3,CHEN Yong1 & JI LinHong4 1 Institute of high Energy Physics,Chinese Academy of Sciences,Beijing 100049,china 2.{2. of Mathematical Sciences,Peking university,Beijing 100871,china 3.high school of central university for nationalities,Beijing 100081,china 4 Institute of Mechanical Design,Department of Precision Instruments and Mechanology,Tsinghua university,Beijing 100084,china 5 Academy of Opto-electronics,Chinese Academy of Sciences,Beijing 100190,china 1. Institute of high Energy Physics Chinese Academy of Sciences Beijing 100049 China5. Academy of Opto-electronics Chinese Academy of Sciences Beijing 100190 China2. School of Mathematical Sciences Peking University Beijing 100871 China3. High School of Central University for Nationalities Beijing 100081 China4. Institute of Mechanical Design Department of Precision Instruments and Mechanology Tsinghua University Beijing 100084 China

It is well-known that the numerical value is always larger than the measured value,amounting to many times,if we calculate the stress of the specimen in the impulse test using the NASTRAN and ANSYS (N-A) *** believe that the impact induces shock wave or quasi-traveling wave in the specimen,which can qualitatively explain the discrepancy of the two *** order to verify it,the Lax-Friedrichs (L-F) scheme is taken to simulate the transmission of shock wave and quasi-traveling wave in *** results show that the action area of the stress wave is small and the action time is very short,so the resulting stress and actual work are not *** addition,the distribution of the impact values obtained by the numerical simulation is in accordance with the trend of the measured impact values.

关键词： aerospace environment test shock wave quasi-traveling wave

Analysis for twinning and slip in face-centered cubic crystals under axisymmetric co-deformation

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Science china(Technological Sciences) 2006年第5期49卷 521-536页

作者： CHEN Zhiyong1,2. CAI Hongnian1, ZHANG Xinming2. WANG Fuchi1 & TAN Chengwen1,3 1. school of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081, {2. 2. school of Material Science and Engineering, central South university, Changsha 410083, {2. 3. school of Material Science and Engineering, Beijing university of Aeronautics and Astronautics, Beijing 100083, {2. 1. school of Material Science and Engineering Beijing Institute of Technology Beijing 100081 China 2. school of Material Science and Engineering Central South University Changsha 410083 China 3. school of Material Science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

The maximum work principle of Bishop-Hill was developed to analyze the axisymmetric co-deformation in face-centered cubic crystals (f.c.c.) for twinning on {111} 112.and slip on {111} 110 systems. The influence of ξ , the ratio of critical re- solved shear stress for twinning to slip, on the yield stress states and corresponding active slip or/and twinning systems for orientations in the standard stereographic triangle of cubic crystal was investigated systematically. The Taylor factors and the anisotropy of yield strength for three important orientations [100], [110] and [111] in orientation space were analyzed. It is found that the yield strength asymmetry for the case of axisymmetric de- formation of tension and compression can be explained based on the microscopic theory of crystal plasticity. The concept of orientation factor for twinning ability was proposed and the deformation mechanism map in the orientation space was established for the case of axisymmetric deformation. The deformation texture formation and development of f.c.c. crystals with low stacking fault energy for axisymmetric tension can be explained qualita- tively on the basis of analyzed results.

关键词： twinning slip face-centered cubic crystals axisymmetric co-deformation Bishop-Hill maximum work principle yield strength anisotropy

Singular Integral Equations with Cosecant Kernel in Solutions with Singularities of high Order

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Wuhan university Journal of Natural Sciences 2005年第2期10卷 339-343页

作者： HAN Hui-li 1,2.,DU Jin-yuan 1,3 1. school of Mathematics and Statistics, Wuhan university, Wuhan 430072. Hubei, {2. 2. school of Mathematics and Computer, Ningxia university, Yinchuan 75002., Ningxia, {2. 3. Department of Mathematics, Hubei Institute for nationalities, Enshi 445000, Hubei, {2. Wuhan university School of Mathematics and Statistics Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) Ningxia university School of Mathematics and Computer Yinchuan Ningxia China (GRID:grid.260987.2) (ISNI:***) Wuhan university School of Mathematics and Statistics Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) Hubei Institute for nationalities Department of Mathematies Enshi Hubei China (GRID:grid.34418.3a) (ISNI:***)

We have discussed and solved the boundary value problem with period 2.π and the singular integral equation with kernel csc t-tv/a in solution having singularities of high order, where the smooth contour of integratio... 详细信息

关键词： boundary value problem singular integral equation the singularities of high order

Electrochemical Characterization of Surface-modified LiMn_2._4 Cathode Materials for Li-ion Batteries

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Journal of Wuhan university of Technology(Materials Science) 2006年第4期21卷 56-59页

作者：禹筱元 College of Science South China Agricultural University Guangzhou 510642ChinaSchool of Physics & Engineering Sun Yat-sen University Guangzhou 510275China

To improve the performance, the surface of 12.n2.4 was coated with very fine MgO , Al2.3 and ZnO by solgel method, respectively. The structure and morphology of the coated materials were investigated by X-ray diffraction （ XRD ）, X-ray photoelectron spectroscopy （ XPS ） and scanning electron microscopy （SEM）. The charge and discharge performance of uncoated and surfnce modified 12.n2.4 spinel at 2.℃ and 55 ℃ were tested, using a voltage window of 3.0-4.35 V and a current deasity of 0. 1 C rate. There is a slight decrease in the initial discharge capacity relative to that of uncoated UMn2.O4, bat the cycle ability of 12.12.n2.4 coated by metal-oxide has remarkably been improved. The EIS measuremeuts of uncoated and Al2.3 -coated 12.n2.4 were carried out by a model 2.3 A potentiostatl galvanistat controUed by a computer using M2.0 software, and using a freqnency response analyzer （ Zsimpwin ） combined with a potentiostate （ PAR 2.3）. Coaseqnently, the reason for the improved cycle properties is that the surface modification reduces the dissolution of Mn , which results from the suppression of the electrolyte decomposition, and suppresses the formation of passivation film that acts as an electronic insulating layer. In conclusion, the use of surface modification is an effective way to improve the electrochemical performance of 12.n2.4 cathode material for lithium batteries.

关键词： lithium-ion batteries surface modification metal-oxide coating: 12.n2.4 cathode

Characteristic atom arranging crystallogphy of alloy phases for Au-Cu system

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Science china(Technological Sciences) 2011年第6期54卷 1560-1567页

作者： XIE YouQing1,2.3,LIU XinBi1,2.3,PENG HongJian4,NIE YaoZhuang5,LI XiaoBo6 & LI YanFen1,2.3 1 school of Materials Science and Engineering,central South {2.,Changsha 410083,china 2.Powder Metallurgy Research Institute,central South {2.,Changsha 410083 china 3 State Key Laboratory of Powder Metallurgy,central South {2.,Changsha 410083,china 4 school of Chemistry and Chemical Engineering,central South {2.,Changsha 410083,china 5 school of Physical Science and Technique,central South {2.,Changsha,410083,china 6 College of Mechanical Engineering,Xiangtan {2.,Xiangtan 411105,china 1. school of Materials Science and Engineering Central South University Changsha 410083 China2. Powder Metallurgy Research Institute Central South University Changsha 410083 China3. State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China4. School of Chemistry and Chemical Engineering Central South University Changsha 410083 China5. School of Physical Science and Technique Central South University Changsha 410083 China6. College of Mechanical Engineering Xiangtan University Xiangtan 411105 China

In this paper,it is pointed out that the descriptions of alloy phase structures are dependent on structural unit *** the systematic science of alloys(SSA),the alloy phase structures are described by means of the symmetry element sequence combining with characteristic atom *** is named the characteristic atom arranging structure,which can display the characteristic atoms at the lattice sites and the micro-inhomogeneity,besides the *** characteristic atom has its own characters:neighboring configuration,potential energy,volume and electronic *** micro-inhomogeneity of alloy phases can be described by concentrations and short-range ordered parameters of characteristic *** differences between the electronic structures of alloy phases and electronic structures of characteristic atoms in the alloy phases are also discussed.

关键词： systematic science of alloys Au-Cu system alloy phase structure micro-inhomogeneity

Conductance and dielectric properties of pure C_(60) single crystal

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Chinese Science Bulletin 1997年第1期42卷 40-43页

作者： YANG Guoquan, WANG Gang, WEN Weijia, ZHOU Weiya, LU Kunquan and XIE Sisheng1. central university for {2., Beijing 100081, china 2. Institute of Physics, Chinese Academy of Sciences, Beijing 100080, china central university for {2. Beijing China Institute of Physics Chinese Academy of Sciences Beijing China

THE C60 is the third stable allotrope of carbon. Much attention has been focused on C60 since it has unique properties. Much work has been carried out on it, such as the preparation of large quantities of C60, the structure studies of C60, the superconducting alkali-metal-C60 compounds, the growth of pure C60 single crystal. There is still a lot of work to do in detail, but because the size of the single ctystal is not large enough, there is some difficulty in research, for example, the electric and optical properties of the C60 single crystal.

关键词： C60 single crystal vapor phase growth conductance dielectric properties.

Permian carbonates of Baoshan block, Western Yunnan and their paleoclimatic implications

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Science china Earth Sciences 2004年第5期47卷 385-392页

作者： YAN Jiaxin1, LIANG Dingyi1 & WU Ming2.1. Faculty of Earth Sciences, china university of Geosciences, Wuhan 430074, china 2. College of Chemistry and Life Sciences, South-central university for nationalities, Wuhan 430074, china china Univ Geosci Fac Earth Sci Wuhan 430074 Peoples R China S Cent Univ National Coll Chem & Life Sci Wuhan 430074 Peoples R China

Recently, much attention has been paid to the climatic significance of carbonates originating in shallow water. Permian carbonates of shallow shelf origin are present in the upper part of the Dingjiazhai Formation, the upper part of the Yongde Formation, and the Shazipo Formation on the Baoshan block of Western Yunnan. Their skeleton and non-skeleton grain as-sociations have been investigated in this study. The carbonates of the Dingjiazhai Formation indicate a Bryonoderm (bryozoans-echinoderm) association without non-skeleton grains. The carbonates of Yongde and Shazipo formations show Chloroforam (green algae-foraminifers) association with peloids. Oolites develop in the Shazipo Formation. Based on the comparisons of grain association with coeval carbonates formed in different paleolatitudes (i.e. various paleo-climatic zones), the carbonates of the Dingjiazhai Formation were thought to have been accu-mulated in shelf environments of warm-temperate zone, and those of the Yongde and Shazipo formations in shelf environments of warm-water.

关键词： Early Permian, carbonate, paleoclimate, Western Yunnan.

Study on Transformation of CaO-Al_2._3-SiO_2.MgO System Inclusions in ZG06Cr13Ni4Mo Stainless Steel

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Journal of Iron and Steel Research International 2011年第S2期18卷 341-346页

作者： LIU Jian-hui1,3, DONG Han1,3, ZHU Rong2. LI Shi-qi2.(1. Institute for Structural Materials,central Iron and Steel Research Institute, Beijing 100081,{2. 2. school of Metallurgical and Ecological Engineering,university of Science and Technology Beijing, Beijing 100083,{2. 3. National Engineering Research Center of Advanced Steel Technology, Beijing 100081,{2.) Cent Iron & Steel Res Inst Inst Struct Mat Beijing 100081 Peoples R China Univ Sci & Technol Beijing Sch Met & Ecol Engn Beijing 100083 Peoples R China Natl Engn Res Ctr Adv Steel Technol Beijing 100081 Peoples R China

This paper aims at generally studying on the inclusions of ZGG06Cr13Ni4Mo ultra-low carbon stainless steel used for large scale hydraulic turbine sets. On the basis of analysis the industrial test samples, thermodynamic software FactSage is used to study inclusions transformation process in CaO-SiO2.Al2.3-MgO system while stainless steel is been smelting. The results illustrate the inclusions melting points and plasticity variation law. The reasonable inclusions plasticity controlling area is found out in low melting point. The melting point is up to 12.0℃ While MgO weight concentration is 10% in CaO-SiO2.Al2.3-MgO system, SiO2. Al2.3 and CaO in inclusions are in weight concentration range of 50-70%, 10-2.% and 10-40%, respectively. For purpose of gaining low melting point inclusions, silicon alumina radio in deoxidant should be controlled between 2.5 for ultra-low carbon stainless steel refining in industry.

关键词： ZG06Cr13Ni4Mo stainless steel low melting point inclusion thermodynamic calculation

EXISTENCE OF GLOBAL SMOOTH SOLUTION TO INITIAL BOUNDARY VALUE PROBLEM FOR A VISCOELASTIC MODEL WITH RELAXATION

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Acta Mathematica Scientia 2004年第2期24卷 265-274页

作者：阮立志朱长江 LaboratoryofNonlinearAnalysis Dept.ofMath.CentralChinaNormalUniversityWuhan430079China

This paper is concerned with the initial boundary value problem for a viscoelastic model with relaxation. Under the only assumption that the C^0-norm of the initial data is small, without smallness hypothesis for the C^1-norm, the existence of the global smooth solution to the corresponding initial boundary value problem is proved. The analysis is based on some a priori estimates obtained by the 'maximum principle' of first-order quasilinear hyperbolic system.

关键词： Viscoelastic model relaxation a priori estimates maximum principle