材料期刊网

A Method of Observing Fatigue Crack Growth by SEM

MU Ensheng LIN Jizhong WU Yushu HU Yixiang CHENG Zhaoyin **Dept.of Metals and Chemistry , China Academy of Railway Sciences , Beijing 100081 , China*** Center Laboratory , Dalian Locomotive Factory of Railway Ministry , Dalian , 116021 , China+ To whom correspondence s

材料科学技术（英文）

This paper introduces a modified control cir- cuit of static tensile stage of Cambridge S-200 SEM.The function of the stage is extended to that of a tensile/compressive dynamic fatigue testing stage.It can be used for studying fatigue micro characteristic and crack growth.Direct observa- tions of small crack growth behaviour were carried out under the SEM with modified stage.Results showed the various stages in the development of a crack.

关键词: SEM , null , null

Metal-Free Heterogeneous Catalysis for Sustainable Chemistry

Chemsuschem

The current established catalytic processes used in chemical industries use metals, in many cases precious metals, or metal oxides as catalysts. These are often energy-consuming and not highly selective, wasting resources and producing greenhouse gases. Metal-free heterogeneous catalysis using carbon or carbon nitride is an interesting alternative to some current industrialized chemical processes. Carbon and carbon nitride combine environmental acceptability with inexhaustible resources and allow a favorable management of energy with good thermal conductivity Owing to lower reaction temperatures and increased selectivity, these catalysts could be candidates for green chemistry with low emission and an efficient use of the chemical feedstock This Review highlights some recent promising activities and developments in heterogeneous catalysis using only carbon and carbon nitride as catalysts The state-of-the-art and future challenges of metal-free heterogeneous catalysis are also discussed.

关键词: carbon;catalyst;heterogeneous catalysis;selectivity;sustainable;chemistry;graphitic carbon nitride;modified activated carbon;nanofiber/graphite-felt composite;ordered mesoporous carbons;oxygen;reduction reaction;nitrogen-doped graphite;fuel cell cathode;onion-like carbon;oxidative dehydrogenation;hydrogen-production

用DEPT135测定Resol的组成及微细结构参数

杨金瑞 , 余尚先 , 顾江楠

高分子材料科学与工程

通过对resol(羟甲基酚化合物和低分子量羟甲基酚树脂)DEPT135图谱的分析讨论,得到一系列计算resol微细结构参数的经验公式.根据DEPT135图谱可判断是否发生缩聚反应,根据经验公式可计算酚单体各个活性点参与反应百分率或酚羟基导入率、不同类型缩聚所占百分率及低分子量羟甲基酚树脂的平均核体数.

关键词: 羟甲基酚化合物 , 羟甲基酚树脂 , DEPT135 , 结构参数

小角度直线反走样的改进Wu算法

李铂 , 周建江 , 夏伟杰 , 吴连慧

液晶与显示 doi:10.3788/YJYXS20142904.0605

直线是机载座舱显示画面中最基本的图元,其显示质量对于整个画面的显示效果影响较大,尤其是小角度下直线显示的“麻花”现象一直是影响显示效果的关键问题之一.为了提高小角度下直线的显示效果,本文提出了一种基于Wu算法的亮度渐变改进算法.该算法通过渐进地展现直线从轴方向上的亮度变化过程,减少亮度畸变,有效地改进了显示效果.通过Matlab仿真和FPGA实现,验证了该算法反走样后的小角度直线显示效果明显优于其他算法,而且结合中点画线法后,绘制时间与Wu算法相当.同时该算法还可改善大角度直线和圆弧的显示效果,消除了大角度直线的边缘锯齿,解决了圆弧在小角度部分的虚化问题.因此本文算法可用于对实时性和显示效果要求高的机载座舱显示系统,以缓解飞行员的视觉疲劳.

关键词: 座舱显示 , 反走样 , 改进Wu算法 , 小角度 , FPGA实现

116HU聚酯亚胺无挥发浸渍树脂的性能及其在风电上的模拟结构试验

王君 , 邹家桂 , 陈政标 , 高建武 , 刘彦坤 , 张杰元 , 宋莎

绝缘材料

　　为解决苯乙烯和甲基苯乙烯在VPI浸渍树脂应用于风力发电机中的不足，采用不饱和聚酯亚胺、引发剂和无挥发活性稀释剂研制出116HU聚酯亚胺无挥发浸渍树脂，并对其各项性能进行了研究。结果表明：116HU聚酯亚胺无挥发浸渍树脂的常规性能满足风力发电机的要求，其耐热等级可达H级。用该树脂浸渍的风电模拟线棒具有优异的介电性能、耐湿热交变和高低温循环冲击性能及耐盐雾性能等，能满足风力发电机在极端环境运行的要求。

关键词: 聚酯亚胺 , 无挥发 , VPI , 风力发电机 , 耐湿热 , 耐盐雾

Nanocrystal Model for Liquid Metals and Amorphous Metals

X.L. Tian C.W. Zhan J.X. Hou X.C. Chen J.J. Sun

材料科学技术（英文）

A nanocrystal model for liquid metals and amorphous metals has been developed. With the nanocrystal model, the broadening peak profiles (BPPs) of Cu, Al, Al₆₅Cu₂₀Fe₁₅ alloy, Cu₇₀Ni₃₀ alloy and Fe₅₀Si₅₀ alloy were gained by broadening the X-ray diffraction (XRD) peaks of a crystal lattice. By comparing the BPPs with the XRD intensity curves measured on the liquid metals, it is found that the BPPs are closely in agreement with the XRD intensity curves, respectively, except the Fe₅₀Si₅₀ alloy. Therefore, the nanocrystal model can be used to determine if the atomic cluster structure of the liquid metal is similar to the structure of its crystal lattice.

关键词: Liquid metal , Atomic Cluster , Structure , Crystal Lattice

Calculation of specific surface area of foam metals using dodecahedron model

Materials Science and Technology

A pentagonal dodecahedron model of metal foam with open cells was considered for calculation of specific surface area. of the high porosity metals. According to the pentagonal dodecahedron model the authors calculate the specific surface area of nickel foam samples with the cell size of similar to 200 mu m and find it approximate agreement with the results obtained by other methods, and the specific surface area of metal foams is correlated with cell size and the width of cell wall.

关键词: specific surface area;dodecahedron;model;foam metal;adsorption

Twinnability Predication for fcc Metals

B.Q. Li

材料科学技术（英文）

Inherent twinnability of face-centered-cubic (fcc) metals was analyzed based on the direct competition between twinning partial dislocation nucleation and trailing partial dislocation nucleation, with which the twinnability of fcc metals can be simply expressed as function of the stacking-fault energy, the unstable stacking-fault energy, and the unstable twinning-fault energy of fcc metals. The predicted twinnability ranking matched well with former experimental results and provided a physical insight to understand twinnability from crystallographic orientation and fault energy parameters.

关键词: Deformation twinning

Twinnability Predication for fcc Metals

材料科学技术（英文）

Inherent twinnability of face-centered-cubic (fcc) metals was analyzed based on the direct competition between twinning partial dislocation nucleation and trailing partial dislocation nucleation, with which the twinnability of fcc metals can be simply expressed as function of the stacking-fault energy, the unstable stacking-fault energy, and the unstable twinning-fault energy of fcc metals. The predicted twinnability ranking matched well with former experimental results and provided a physical insight to understand twinnability from crystallographic orientation and fault energy parameters.

关键词: Deformation twinning;fcc metals;Twinnability;deformation twins;nanocrystalline aluminum;plastic-deformation;low;temperatures;single crystals;crack-tip;alloys;nucleation;copper

基于Wu反走样的三角形光栅化边缘反走样算法

吴连慧 , 周建江 , 夏伟杰 , 陈雅雯

液晶与显示 doi:10.3788/YJYXS20153001.0163

对于光栅化的三角形,其边缘存在明显的锯齿现象,因此需要进行反走样处理.基于Wu直线反走样算法的思想,考虑了水平直线外侧直接添加插值点的算法和三角形三边外侧反走样的算法.综合两者的优点,在绘制光栅化的三角形的同时,边缘叠加Wu反走样直线,并考虑背景像素灰度值的作用.结果表明,改进的三角形光栅化的边缘反走样算法有效提高了三角形光栅化后边缘的显示效果,该算法计算量小,便于FPGA实现,可用于对图形显示质量要求很高的机载显示系统.

关键词: 反走样 , Wu算法 , 光栅化 , FPGA