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Finite Element and Experimental Analysis of Three-Dimensional Flow State of Plastic Melt in Slit Die Section

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Finite Element and Experimental Analysis of Three-Dimensiona...

第五届国际材料与热加工物理模拟及数值模拟学术会议

作者： Shengxue QIN 1 a Guoqun ZHAO 2.b Yue MU 2.c Xingming XU 2.d 1 College of Mechanical and Electrical engineering Shandong university of {2. and technology Qingdao 2.6510 China 2.Mold & Die engineering Technology Research Center Shandong university Jinan 2.0061 China

In this paper, penalty finite element method is applied to the simulation of three-dimensional incompressible viscous steady flow, and the program is coded for analysis of three-dimensional flow process of plastic melt in extrusion die. Slit die is typical in polymer extrusion process, and the relevant part is used widely. Because the flow law is different for various polymers with different rheological character even in the same die, the polymer flow in slit die is simulated for Newtonian fluid and power-law fluid by the program and ANSYS respectively. Flow law of two kind of fluid is compared, and the result shows that the non-uniform velocity distribution in outlet is caused by the non-Newtonian effect of material. The penalty factor is important for the penalty finite element model, which decides the precision and efficiency to a great extent. The proper penalty value is decided by some factors, for example, the character of the whole equations and geometric model. Numerical solution with change of penalty value and viscosity is analyzed, and the result shows that the penalty value should be suited with viscosity in special range for penalty finite element model. The experiment has been developed, and the velocity distribution in outlet of slit die is measured. The result of finite element analysis is consistent with experimental result basically, and the reason of result divergence of the two ways is analyzed. The results showed that the given model is suited for the polymer extrusion process, and the advice of the selection of penalty value is instructional for penalty element model.

关键词： Finite element Extrusion Slit die Numerical simulation Polymer

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SiC纳米粉表面研究

无机材料学报 1998年第1期13卷 99-104页

作者：杨修春韩高荣李福丁子上周国治北京科技大学理化系北京100083 浙江大学材料系 310027

借助于TEM、IR和XPS分析；对新鲜的SiC纳米粉表面和不同存放时间及处理条件下的样品表面进行分析比较，发现新鲜的作品表面主要以物理吸附氧为主（78.2.％），化合态氧为辅（2..75％），在空气中存放一个月后，O／Si比由新鲜样品表面的0... 详细信息

借助于TEM、IR和XPS分析；对新鲜的SiC纳米粉表面和不同存放时间及处理条件下的样品表面进行分析比较，发现新鲜的作品表面主要以物理吸附氧为主（78.2.％），化合态氧为辅（2..75％），在空气中存放一个月后，O／Si比由新鲜样品表面的0.49上升至0.70表面发生氧化,继续存放一个月，O／Si比增至0．77；但表面氧化速度变缓,在潮湿空气中SiC纳米粉更易氧化．离子刻蚀分析表明，O主要分布在粉末表面．

关键词：表面氧化碳化硅纳米级结构陶瓷粉末原料

Quadratic and cubic eddy-viscosity models in turbulent supercavitating flow computation

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Theoretical & Applied Mechanics Letters 2011年第3期1卷 66-70页

作者： Ying Chen,~(1,a)) Chuanjing Lu,~(1,2. and Xin Chen~1 1)department of engineering Mechanics,School of Naval Architecture,Ocean and Civil engineering, Shanghai Jiao Tong university,Shanghai 2.02.0,China 2.State Key Laboratory of Ocean engineering,Shanghai Jiao Tong university,Shanghai 2.02.0,China Shanghai Jiao Tong Univ Dept Engn Mech Sch Naval Architecture Ocean & Civil Engn Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ State Key Lab Ocean Engn Shanghai 200240 Peoples R China

Quadratic and cubic non-linear eddy-viscosity turbulence models(NLEVM) with low Reynolds number(Re) correction were presented to provide better description of anisotropic turbulence stresses in the numerical prediction of supercavitating flows,which are accompanied with large density ratio and large-scaled swirling flow *** applications of the NLEVM were carried out through a self-developed cavitation codes,coupled with a cavitation model based on the transport equation of liquid *** NLEVM were verified capable of capturing more accurate macroscopic shape and hydrodynamic property of supercavity by the benchmark problems of supercavities over simple ***,the cubic NLEVM was further applied to the numerical prediction of supercavitating flow around a complex submerged *** corresponding cavitation behaviors were explored in detail to provide beneficial experience for further research.

关键词： supercavitating flow numerical simulation non-linear turbulence model

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熔融共混法制备EBA／LDH纳米复合材料

武汉理工大学学报 2009年第8期31卷 25-28页

作者：黄年华李治华刘肖王维王建祺新型纺织材料绿色加工及其功能化教育部重点实验室武汉科技学院武汉430073 武汉科技学院高分子科学与工程系武汉430073 北京理工大学阻燃材料国家专业实验室北京100081

通过熔融共混法制备出剥离型乙烯-丙烯酸丁酯共聚物(EBA)/MgAl层状双氢氧化物(LDH)纳米复合材料。采用XRD、透射电镜(TEM)和热重分析(TGA)等技术对纳米复合材料的结构、形貌、热性能及力学性能进行了研究。XRD、FTIR和TEM结果表明,十二... 详细信息

通过熔融共混法制备出剥离型乙烯-丙烯酸丁酯共聚物(EBA)/MgAl层状双氢氧化物(LDH)纳米复合材料。采用XRD、透射电镜(TEM)和热重分析(TGA)等技术对纳米复合材料的结构、形貌、热性能及力学性能进行了研究。XRD、FTIR和TEM结果表明,十二烷基单磷酸根离子(PK)嵌入了LDH层间,使LDH的层间距显著增大;在强剪切力作用下,有机化的LDH可在熔融的EBA基体中剥离成纳米片层,均匀地分散在EBA的基体中。随着LDH含量的增加,纳米复合材料的拉伸强度和断裂伸长率先增后降,在LDH的含量为3%和2.时分别达到最大值。当LDH的质量百分含量为2.时,纳米复合材料的热起始分解温度(T10%)相比于纯EBA提高2.℃,LDH能够促进EBA成炭。

关键词：乙烯-丙烯酸丁酯共聚物层状双氢氧化物纳米复合材料熔融共混

Preparation and microstructure characterization of a nano-sized Ti^(4+)-doped AgSnO_2.electrical contact material

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Rare Metals 2009年第1期28卷 19-23页

作者： ZHENG Ji LI Songlin DOU Fuqi LI Tonghui Tianjin Key Laboratory of Composite and Functional materials School of Materials Science and Engineering Tianjin University Tianjin 300072 China

A Ti^4＋-doped nano-structured AgSnO2.material was prepared using sol-gel method and characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and scanning electron microscopy （SEM）. The results show that Ti^4＋ cations are successfully doped into the crystal lattice of SnO2. and thus significantly improve the electrical conductivity of the sample. Furthermore, the coating of Ag on Ti^4＋-doped SnO2.nano-sized particles enhances the surface wettability and enables the resulting AgSnO2.material to have better mechanical properties.

关键词： electrical contact material sol-gel process doping chemical coating silver

PA6超微化及PA6/PP/硅灰石复合材料制备新方法

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武汉化工学院学报 2001年第3期23卷 35-38页

作者：刘长生王琪武汉化工学院材料工程系湖北武汉430073 四川大学高分子研究所四川成都610065

采用粒度分析、透射电镜观察、分子量测定及力学性能测试等手段研究尼龙 6( PA6)及与聚丙烯接枝马来酸酐 ( PP g MAH)和硅灰石混合的 PA6在碾磨力场作用下的结构及力学性能的变化 ,实现了 PA6的超微化 ,使用碾磨共混所得的 PA6/PP g MAH... 详细信息

采用粒度分析、透射电镜观察、分子量测定及力学性能测试等手段研究尼龙 6( PA6)及与聚丙烯接枝马来酸酐 ( PP g MAH)和硅灰石混合的 PA6在碾磨力场作用下的结构及力学性能的变化 ,实现了 PA6的超微化 ,使用碾磨共混所得的 PA6/PP g MAH/硅灰石混合微粉制备了 PA6/PP/硅灰石复合材料 .研究表明 ,在碾磨力场作用下 ,PA6分子链发生断裂 ,粒度减小 ,最小可以达到 80 nm;碾磨过程中聚合物和填料之间的分散和相互作用使 PA6/PP/硅灰石复合材料的力学性能增加 ,其屈服强度最高达到 5

关键词：尼龙6 聚丙烯粉碎复合材料硅灰石制备

Design of the Test Platform of Servo System

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Design of the Test Platform of Servo System

Mechanical engineering and material {2.—2.12.International Conference on Mechanical engineering and material {2.(MEMS 2.12.

作者： Yong-guang Liu School of automation science and electric engineering Beihang {2. Beijng China Qin Lei School of automation science and electric engineering Beihang {2. Beijng China

This paper designs a test platform of servo *** technique method of the test platform of servo system is studied,the structure diagram of the test platform of servo system is given;the way of loading friction resistance torque and moment of inertia respectively are designed,which realizes changing the friction resistance and moment inertia of the system;the real-time measurement and control system based on the Lab Windows/CVI and RTX is designed,which realizes the real-time control;the test platform can truly simulate the actual load of the servo system,assess dynamic and static technology index of the servo system.

关键词： servo system friction resistance torque load moment of inertia load real-time control

Surface Modeling from 3D Unorganized Points

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Surface Modeling from 3D Unorganized Points

2.02.IEEE十区计算机、通信、控制和电机工程会议

作者： LIANG Ronghua CHEN Chun PAN Zhigeng JIN Cheng department of Compute science and {2., Zhejiang university Hangzhou China 31002. department of Computer science and {2., Hangzhou Institute of Electronics {2., Hangzhou China 31002. State Key Lab of CAD&CG, Zhejiang university Hangzhou China 31002.

Surface modeling from 3D unorganized points is ofgreat importance in variable fields such as computer vision,images based modeling, scientific computing visualization, etc..In this paper we present a new algorithm based on HuguesHoppe algorithm. First these points are divided into logicalcubes whose size is decided automatically from theunorganized points. Then the tangent planes and normal vectorsat each point are calculated and the normal vectors areorientated to the outside of surface based on WFS. Finally thesurface model of triangular meshes can be obtained by theoutput of Marching Cubes. Experimental results show the highefficiency of the algorithm.

关键词： 3D triangulation WFS Marching Cubes iso-surface

Transplantation of neural stem cells and hyaluronic acid based scaffold for treatment of rat ischemic stroke

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Transplantation of neural stem cells and hyaluronic acid bas...

中国神经科学学会第四次会员代表大会暨第八届全国学术会议

作者： Ying WANG~1 Li-Li XIAO~1 Yong-Juan REN~2.Fu-Zhai CUI~2.Qun-Yuan XU~(1 *) 1 Beijing Institute for Neuroscience Capital Medical university Beijing 100069 China 2.2. of materials science and engineering Tsinghua university Beijing 100084 China

Introduction Stroke causes death and severe disability highly and often results in cavity formation in the brain. The complexity and the limited regeneration of brain tissue make efforts to repair

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