材料期刊网

Numerical Simulation and Sensitivity Analysis of Parameters for Multistand Roll Forming of Channel Section With Outer Edge

ZENG Guo , LAI Xinmin , YU Zhongqi , LIN Zhongqin

钢铁研究学报(英文版)

Cold roll forming is a high production but complex metal forming process under the conditions of coupled effects with multifactor. A new booting finite element method (FEM) model using the updated Lagrangian (UL) method for multistand roll forming process is developed and validated. Compared with most of the literatures related to roll forming simulation, the new model can take the roll rotation into account and is well suited for simulating multistand roll forming. Based on the model, the process of a channel section with outer edge formed with twelve passes is simulated and the sensitivity analysis of parameters is conducted with orthogonal design combined FEM model. It is found that the multistand roll forming process can be efficiently analyzed by the new booting model, and sensitivity analysis shows that the yield strength plays an important role in controlling the quality of the products.

关键词: cold roll forming;multistand;roll forming;sensitivity;FEM model

ACRT-B法生长的MnxCd1-xIn2Te4晶体的溶质分凝特性

常永勤 , 介万奇 , 郭喜平 , 陈福义 , 安卫军

功能材料

研究了ACRT-B法生长的Mn0.1Cd0.9In2Te4晶体中界面的形状和各组元沿轴向的分布规律及其分凝因数.发现结晶界面为椭球形;采用理想配比生长MnxCd1-xIn2Te4晶体,其4种组元并不按(Mn,Cd):In:Te=1:2:4比例结晶,而是要重新分布;通过数学方法处理实验数据得到Mn,Cd和In的分凝因数在α相区分别为1.286、1.9257和0.7294,在β相区则分别为1.12、1.055和0.985.

关键词: ACRT-B法 , MnxCd1-x In2Te4 , 界面 , 分凝因数

Bridgman法生长的Mn_xCd_1-xIn₂Te₄晶体相形成规律和物理性能研究

常永勤 , 安卫军 , 郭喜平 , 介万奇

无机材料学报

采用Bridgman法生长了x为0.1,0.22和0.4的四元稀磁半导体化合物Mn_xCd_1-xIn₂Te₄晶体.研究了三根晶体中相的形貌、结构、成分和Mn_0.1Cd_0.9In₂Te₄晶体中各组元沿轴向和径向的成分分布.晶体生长初始端的组织为α+β+β₁,随着生长的进行,形成β相的单相区.在晶锭末端,形成In₂Te₃类面心立方结构化合物.组分x增大后,Mn_xCd_1-xIn₂Te₄晶体的吸收边向短波方向移动,禁带宽度则线性增大.磁化率测量结果表明:晶体在高温区的x^-1-T曲线服从居里-外斯定律,在低温区(<50K)则表现出顺磁增强现象.

关键词: Mn_xCd_1-xIn₂T_e4 , compositional distribution , infrared transmission spectra , mag- netic susceptibility

Bridgman法生长的MnxCd1-xIn2Te4晶体相形成规律和物理性能研究

常永勤 , 安卫军 , 郭喜平 , 介万奇

无机材料学报 doi:10.3321/j.issn:1000-324X.2003.02.004

采用Bridgman法生长了x为0.1,0.22和0.4的四元稀磁半导体化合物MnxCd1-xIn2Te4晶体.研究了三根晶体中相的形貌、结构、成分和Mno.1Cd0.9In2Te4晶体中各组元沿轴向和径向的成分分布.晶体生长初始端的组织为α+β+β1,随着生长的进行,形成β相的单相区.在晶锭末端,形成In2Te3类面心立方结构化合物.组分x增大后,MnxCd1-xIn2Te4晶体的吸收边向短波方向移动,禁带宽度则线性增大.磁化率测量结果表明:晶体在高温区的x-1-T曲线服从居里一外斯定律,在低温区(＜50K)则表现出顺磁增强现象.

关键词: MnxCd1-xIn2Te4 , 成分偏析 , 红外透射光谱 , 磁化率

THEREVERSSE TRANSFOR MATION OF THE STERSS INDUCEDεMIN FE 17MN 10CR 5SI 4NIALLOY

Q.S. Liu1 , 2 , 3) , L.C. Zhao3) , G.X. Dong2) and N.J. Gu1) 1) Heibei University of Technology , Tianjin 300130 , China 2) Tianjin Institute of Technology , Tianjin 300191 , China 3) Harbin University of Technology , Harbin 150001 , China

金属学报(英文版)

Theconstruction changinginthereversetransformation ofthestress induced εMin Fe 17 Mn 10 Cr 5 Si 4 Ni alloy is carefully inspected in transmission electron microscope, and then stress induced εM procedure of reverse transformation is analyzed. The behavior of reverse transformationisdissimilar when the organization of εMis different. The reversetransfor mation ofεM withtheshapeofsingle plateandstripisrelativelyeasy,anditsreversibilityincrystallographiciseasilytocarryout,fortheεM with multilayerstructure,thereversetrans formationtakes placein isolatedlayers, fortheεMthat grows well,thereversetransforma tion isrelatively difficult becauseofthe ductile harmonization between itsinternalorganiza tion structures.

关键词: stress induced εM , null , null

[C16min]Br修饰的多壁碳纳米管及其与低密度聚乙烯复合材料的制备及介电性能

徐佩 , 卢旭鑫 , 汪传斌 , 杨善中 , 孙晓红 , 丁运生

高分子材料科学与工程

为改善多壁碳纳米管(MWNT)在低密度聚乙烯(LDPE)中的分散性及复合材料的界面特性,采用溴化-1-十六烷基-3-甲基咪唑基离子液体([C16min]Br)对MWNT进行表面改性,并用Raman光谱对改性效果进行了表征.将经过修饰的碳纳米管(MIL)与LDPE熔融共混得到MIL/LDPE复合材料,采用场发射扫描电子显微镜(FESEM)和阻抗分析仪(LCR)对复合材料的结构与介电性能进行了分析.结果表明,相比与MWNT/LDPE(渗流阈值为5.2％,介电常数为82,介电损耗为0.93),MIL/LDPE(渗流阈值为9.1％,介电常数为169,介电损耗为0.51)介电常数增大,介电损耗降低.并且在低温时,MIL/LDPE介电常数随温度的变化甚小,显示出良好的温度-介电常数特性.

关键词: 咪唑基离子液体 , 碳纳米管 , 低密度聚乙烯 , 介电性能

住友金属用QSP工艺进行8m／min的高拉速试验

上海金属

关键词:

MnxCd1-xIn2 Te4晶体生长研究

常永勤 , 安卫军 , 郭喜平 , 介万奇

功能材料

采用Bridgman法生长四元稀磁化合物半导体Mn0.22Cd0.78In2Te4晶体.当晶体生长到预定长度时,淬火得到固液界面.采用光学显微镜、扫描电镜、X射线衍射仪、ISIS能谱仪以及Leica定量金相分析仪研究了晶体中出现的界面形态、相的形貌和数量以及沿生长方向的相析出规律,并进行了相成分分析.研究发现,淬火得到的Mn0.22 Cd0.78In2Te4晶体中存在两个界面,其中一个为固液相变界面,另一个为由α+β两相区发展到单相β区时的转变界面,二者相对于生长初始端均为凹形;α+β两相区中,β相以条状、花状和近似圆片状形式存在,其中条状β相多分布在晶界处;越接近生长初始端,花状和近似圆片状β相越小,条状β相越细,它们的含量越少;X射线衍射图谱表明,β相为黄铜矿结构,α相为面心立方结构.

关键词: MnxCd1-xIn2Te4 , 相变界面 , β相 , X射线衍射图谱

Composition Distribution in the MnxCd1-xIn2Te4 Ingot Grown by ACRT-B Method

材料科学技术（英文）

关键词:

THERMODYNAMIC PROPERTIES OF ALPHA-HELIX PROTEIN - A SOLITON APPROACH - COMMENT

Physical Review E

We disagree with the deduction of the equations of motion for the Davydov soliton and of the results in the paper by Jia-Xin Xiao et al. [Phys. Rev. A 44, 8375 (1991)]. The weakness and faults of the Davydov theory are also indicated.

关键词: davydov solitons;vibron solitons;molecules;excitation;system