LI Qingsheng
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(Chingshen Li)Taiyuan University of Technology
,
Taiyuan
,
China T.BRETHEAU Laboratory PMTM
,
CNRS
,
University Paris Nord Dept.of Mathematics and Mechanics
,
Taiyuan University of Technology
,
Taiyuan 030024
,
China
金属学报(英文版)
The effect of grain boundaries on cyclic deformation and fatigue crack growth in aluminum bicrystals has been studied.The effect of a grain boundary is restricted in a narrow area, termed as grain boundary affecting zone(GBAZ),where the incompatible plastic strain treats internal stress which conversely promotes inhomogeneous slip in the area and grain boundary cracking.As an extended stage I crack initiated from a notch approaches the grain boundary under a constant cyclic stress,the crack front branches splits into several pieces, meanwhile,the growth rate of the crack reduces to a minimum value at the center of the GBAZ.Such microstructure-sensitive growth of extended stage I cracks is mainly attributed to the grain boundary-induced crack tip sheilding.
关键词:
compatibility
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null
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null
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null
齐静
,
高颖
,
唐水花
,
姜鲁华
,
闫世友
,
郭军松
,
辛勤
,
孙公权
催化学报
以间苯二酚和甲醛为碳前体,合成了一种新型碳纳米材料碳纳米带(CNRs), 并采用透射电镜(TEM)、 X射线衍射(XRD)及氮气吸附/脱附测试对CNRs进行了结构表征. 结果表明,所合成的CNRs具有很高的石墨化程度及较规则的带状结构,带宽约为8～20 nm, BET比表面积为283 m2/g, 氮气等温线为type-Ⅳ型,表明CNRs为中孔结构,平均孔径约为8.2 nm. 以CNRs为载体通过多元醇法制备了45%PtRu/CNRs电催化剂,该催化剂与以Vulcan XC-72R为载体的PtRu电催化剂相比,直接甲醇燃料电池单池性能得到明显提高.
关键词:
电催化剂
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载体
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碳纳米带
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直接甲醇燃料电池
鄢定祥
,
高杰峰
,
彭舜
,
谭奎
,
付建伟
,
黄伟
,
袁博
,
李忠明
高分子材料科学与工程
制备了低逾渗值的超高分子量聚乙烯(UHMWPE)/多壁碳纳米管(CNTs)导电复合材料,CNrs分布于UHMWPE粒子的表面和界面处.研究了UHMWPE/CNTs复合材料的温度电阻行为,发现在基体熔点附近,电阻急剧增加,并达到一最大值,然后电阻开始下降,体现负温度电阻效应(NTC).分析了复合材料电阻松弛时间的升温速率的依赖性,结果表明,升温速率越快,电阻的松弛时间越短.
关键词:
碳纳米管
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超高分子量聚乙烯
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正温度系数
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负温度系数
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松弛
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导电复合材料
