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STRUCTURE EVOLUTION OF POLYMER CHAINS FOR NECKING FORMATION IN HIGH-SPEED FIBER SPINNING PROCESS

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chinese Journal of Polymer science 2006年第1期24卷 1-11页

作者： Hong Zheng Wei Yu Hong-bin Zhang and chi-xing zhou department of Polymer materials science & engineering,shanghai jiao tong university,shanghai 200240,china department of Polymer materials science & engineering Shanghai Jiao Tong University Shanghai 200240 China

Finite element method is used to simulate the high-speed melt spinning process, based on the equation system proposed by Doufas et al. Calculation predicts a neck-like deformation, as well as the related profiles of velocity, diameter, temperature, chain orientation, and crystallinity in the fiber spinning process. Considering combined effects on the process such as flow-induced crystallization, viscoelasticity, filament cooling, air drag, inertia, surface tension and gravity, the simulated material flow behaviors are consistent with those observed for semi-crystalline polymers under various spinning conditions, The structure change of polymer coils in the necking region described by the evolution of conformation tensor is also investigated. Based on the relaxation mechanism of macromolecules in flow field different types of morphology change of polymer chains before and in the neck are proposed, giving a complete prospect of structure evolution and crystallization of semi-crystalline polymer in the high speed fiber spinning process.

关键词： Semi-crystalline Polymer Crystallization High-speed Fiber Spinning Process Conformation Finite Element Method (FEM).

Performance Investigation of Square Concrete-filled Steel Tube Columns

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Journal of Wuhan university of Technology(materials science) 2011年第4期26卷 730-736页

作者：陈兵 department of Civil engineering Shanghai Jiao Tong University

The behaviour of square concrete-filled steel tube columns under concentrical loading was studied. More than one hundred specimens were tested to investigate the effects of thickness of steel tube on the load carrying capacity of the concrete-filled tubular columns （CFTs）. The effect of the grade of concrete and content of expansive agent were also investigated. The effect of these parameters on the confinement of the concrete core was studied as well. From the experimental study it was found that for both CFTs with different strength grade concrete core, the ultimate load carrying capacity increases with the increase in percentage of expansive agent up to 20% but it again decreases at 25% of expansive agent content. It was also shown that the failure mode of CFTs depends on the strength grade of concrete core.

关键词： concrete filled steel tubes concrete columns ultimate capacity expansive agent

An Expert System in FRP Composite Material Design

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Journal of materials science & Technology 2001年第5期17卷 556-560页

作者： Qingfen LI, Zhaoxia CUI and Weimin WANG College of Mechanical & Electrical engineering, Harbin engineering university, Harbin 150001, china Jianhua GAO department of Mechanical engineering, shanghai jiao tong university, shanghai 200030, china Coll. of Mech. and Electron. Eng. Harbin Eng. Univ. Harbin 150001 China

An expert system prototype for fibre-reinforced plastic matrix (FRP) composite material design, ESFRP, has been developed. The system consists of seven main functional parts: a general inference engine, a set of knowledge bases, a material properties algorithm base, an explanation engine, various data bases, several function models and the user interface. The ESFRP can simulate human experts to make design scheme for fibre-reinforced plastics design, FRP layered plates design and FRP typical engineering components design. It can also predict the material properties and make strength analysis according to the micro and macro mechanics of composite materials. A satisfied result can be gained through the reiterative design.

关键词： An Expert System in FRP Composite Material Design FRP

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

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science china(Physics,Mechanics & 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, university of science and Technology of china, Hefei 230026, china 2 department of Physics Electronic and engineering, chizhou university, chizhou 247000, china 3 department of Physics, shanghai jiao tong university, shanghai 200030, china 4 College of Optoelectronic engineering, Changzhou Institute of Technology, Changzhou 213002, 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

Virtual multi-dimensional internal bonds model and its application in simulation of rock mass

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science china(Technological sciences) 2008年第2期51卷 192-201页

作者： ZHANG ZhenNan1,2 & GE XiuRun3,4 1 department of Civil engineering,shanghai university,shanghai 200072,china 2 shanghai Institute of Applied Mathematics and Mechanics,shanghai university,shanghai 200072, china 3 Institute of Geotechnical engineering,shanghai jiao tong university,shanghai 200030,china 4 Institute of Rock and Soil Mechanics,chinese Academy of sciences,Wuhan 430071,china department of Civil engineering Shanghai University Shanghai China shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai China Institute of Geotechnical engineering Shanghai Jiao Tong University Shanghai China Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan China

VMIB (virtual multi-dimensional internal bonds) is a multiscale mechanical model developed from the VIB (virtual internal bond) theory. In VIB theory,the solid mate-rial is considered to consist of random-distributed material particles in microscale. These particles are connected with normal bonds. The macro constitutive relation is derived from the cohesive law between particles. However,in VMIB,the micro particles are connected with both normal and shear bonds. The macro constitutive relation is derived in terms of bond stiffness coefficients. It has been theoretically certified that there exists a corresponding relationship between the two bond stiffness coefficients and the two macro material constants,i.e. the Young’s modulus and Poisson ratio. This corresponding relationship suggests that it should be necessary and sufficient to simultaneously account for the normal and shear interactions between particles. Due to the fact that the fracture criterion is directly incorporated into the constitutive relation,both VIB and VMIB present many advantages in simulating fractures of materials. In the damage model of rock mass,a damage tensor is usually defined to describe the distribution of cracks. The damage value in one direction determines the relative stiffness of rock mass in this direction. In VMIB solid,the relative distribution density of micro bonds in one direction determines the relative macro stiffness of the material in this direction. The effects of the damage value and the relative distribution density of bonds are consistent. To simulate the failure behavior of rock mass with VMIB,the presented paper sets up a quantitative relationship between the damage tensor and the rela-tive distribution density of bonds. Comparison of the theoretical and the experi-mental results shows that VMIB model can represent the effect of distributed cracks on rock mass with this relationship. The presented work provides a founda-tion for further simulating fracture behavior

关键词： VMIB (virtual multi-dimensional internal bonds) rock mass VIB (virtual internal bonds) multi-cracked body numerical simulation

HYDRODYNAMIC SIMULATION TO MOLD FILLING UNDER COUNTER GRAVITY

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Acta Metallurgica Sinica(English Letters) 2000年第2期13卷 780-783页

作者： J.M. Zeng and Y.H. zhou 1) Institute of materials science, Guangxi university, Nanning 530004, china 2) department of materials science and engineering, shanghai jiao tong university, shanghai 200030, china

In situ observations of the flow morphology during mold filling under counter gravity are conducted on a perspex water model by means of flow visualization, high speed photography and pattern processing. The experimental results indicate that influences of the dynamic factors on flow morphology can be expressed quantitatively with the parameterφ(k). The flow field takes on different morphology with change in values of φ(k). For thick and thin walled castings, the main dynamic factors influencing flow morphology are gravity and surface tension respectively. Under general circumstances, F_r and W_e should be equal in their values to guarantee the similarity between the prototype and the model in simulating mold filling under counter gravity by experiment.

关键词： casting mold filling hydrodynamics

SUPERPLASTIC BEHAVIOUR OF A FINE GRAINED TiAl BASED ALLOY TREATED BY MULTI-STEP THERMO-MECHANICAL TREATMENT

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中国有色金属学会会刊：英文版 1998年第1期8卷 108-109页

作者： Huang Baiyun, Deng Zhongyong and He YuehuiPowder Metallurgy Research Institute,Central South university of Technology, Changsha 410083, P. R. chinaSun Jian and Liu Qindepartment of materials science and engineeringshanghai jiao tong university Powder Metallurgy Research Institute Central South University of Technology Changsha 410083 China department of materials science and engineering Shanghai Jiao Tong University Shanghai 200030 China

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关键词： TiAl forging superplasticity

Effect of Solute Drag and Precipitate Pinning on Austenite Grain Growth in Ti-Nb Microalloyed Steels

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Journal of Iron and Steel Research International 2011年第S1期18卷 383-387页

作者： FU Li-ming 1,WANG Huan-rong 2,WANG Wei 2,SHAN Ai-dang 1 (1.School of materials science and engineering,shanghai jiaotong university,shanghai 200240,china 2.department of Structural Steels,Baosteel Research Institute,shanghai 201900,china) shanghai jiao tong Univ Sch Mat Sci & Engn Shanghai 200240 Peoples R China Baosteel Res Inst Dept Struct Steels Shanghai 201900 Peoples R China

A metallurgical model concerning the co-effect of the Nb solute drag and the complex carbonitride precipitates pinning is proposed to predict the recrystallization austenite grain growth of low carbon Nb-containing microalloyed *** analysis,both predicted and experimental,reveals the precipitate pinning plays a dominate role in suppressing the austenite grain growth with less Nb solute drag effect in high temperature region whereas the Nb solute drag predominates in relatively low temperature region.A factor p is suggested to assess the effectiveness of drag and *** pinning and the drag are more effective in restraining grain growth as p>0 and p<0,respectively.A low carbon Nb microalloyed steel and a kind of Ti-modified low carbon Nb steel by Ti substituting for part of Nb are employed to validate the modeling *** theoretical calculations show a good agreement with experimental results.

关键词： grain growth precipitates pinning solute drag Ti-Nb microalloyed steels

Amyloid β-protein differentially affects NMDA receptor-and GABAA receptor-mediated currents in rat hippocampal CA1 neurons

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Progress in Natural science:materials International 2009年第8期19卷 963-972页

作者： Junfang Zhanga, Lei Houb, Xiuping Gao a, Fen Guoa, Wei Jingc, Jinshun Qia, Jiantian Qiaoa a department of Neurobiology, Shanxi Medical university, Taiyuan 030001, china b Anesthesiology department, Shanxi Tumor Hospital, Taiyuan 030013, china c department of Biomedical engineering, shanghai jiao tong university, shanghai 200240, china department of Neurobiology Shanxi Medical University Taiyuan 030001 China Anesthesiology department Shanxi Tumor Hospital Taiyuan 030013 China department of Biomedical engineering Shanghai Jiao Tong University Shanghai 200240 China

Although the aggregated amyloid b-protein (Ab) in senile plaques is one of the key neuropathological features of Alzheimer’s disease (AD), soluble forms of Ab also interfere with synaptic plasticity at the early stage of AD. The suppressive action of acute application of Ab on hippocampal long-term potentiation (LTP) has been reported widely, whereas the mechanism underlying the effects of Ab is still mostly unknown. The present study, using the whole-cell patch clamp technique, investigated the effects of Ab fragments (Ab25–35 and Ab31–35) on the LTP induction-related postsynaptic ligand-gated channel currents in isolated hippocampal CA1 neurons. The results showed a rapid but opposite action of both peptides on excitatory and inhibitory receptor currents. Glutamate application-induced currents weresuppressed by Ab25–35in a dose-dependent manner,andfurtherN-methyl-D-aspartate(NMDA)receptor-mediated currents were selectively inhibited. In contrast, pretreatment with Ab fragments potentiated c-aminobutyric acid (GABA)-induced whole-cell currents. As a control, Ab35–31, the reversed sequence of Ab31–35, showed no effect on the currents induced by glutamate, NMDA or GABA. These results may partly explain the impaired effects of Ab on hippocampal LTP, and suggest that the functional down-regulation of NMDA receptors and up-regulation of GABAA receptors may play an important role in remodeling the hippocampal synaptic plasticity in early AD.

关键词： Amyloid b-protein Glutamate-induced current GABA-induced current Whole-cell patch clamp Hippocampus