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SiCw/Al复合材料在TEM下的拉伸行为 被引量:1
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作者 王德尊 刘宗荣 +2 位作者 姚忠凯 刘钧 耿林 《复合材料学报》 EI CAS CSCD 北大核心 1995年第2期26-31,共6页
在备有拉伸台的透射电镜上原位观察了SiCw/Al复合材料的变形、裂纹萌生及其扩展过程。结果发现,变形初期,位错主要从晶界及SiCw-Al界面处开动,在晶界与晶须周围产生大量位错。裂纹萌生源主要为:(1)材料制备过程中... 在备有拉伸台的透射电镜上原位观察了SiCw/Al复合材料的变形、裂纹萌生及其扩展过程。结果发现,变形初期,位错主要从晶界及SiCw-Al界面处开动,在晶界与晶须周围产生大量位错。裂纹萌生源主要为:(1)材料制备过程中受损伤或破断的晶须;(2)晶须富集区。晶须与晶界对裂纹的扩展有阻碍作用。当裂纹取向与晶须大致垂直时,裂尖在晶须附近钝化然后绕过晶须扩展,当裂纹取向与晶须接近平行时,裂尖在晶须端部附近钝化后沿其一侧扩展。 展开更多
关键词 复合材料 动态拉伸 拉伸 硅碳钨 TEM
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Synthesis of acetals and ketals catalyzed by tungstosilicic acid supported on active carbon 被引量:9
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作者 杨水金 杜心贤 +1 位作者 贺兰 孙聚堂 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE EI CAS CSCD 2005年第5期373-377,共5页
Catalytic activity of activated carbon supported tungstosilicic acidin synthesizing 2-methyl-2-ethoxycarbonylmethyl- 1,3-dioxolane, 2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane, cyclohexanone ethylene ketal, cycl... Catalytic activity of activated carbon supported tungstosilicic acidin synthesizing 2-methyl-2-ethoxycarbonylmethyl- 1,3-dioxolane, 2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane, cyclohexanone ethylene ketal, cyclohexanone 1,2-propa- nediol ketal, butanone ethylene ketal, butanone 1,2-propanediol ketal, 2-phenyl-1,3-dioxolane, 4-methyl-2-phenyl-1,3-dioxolane, 2-propyl-1,3-dioxolane, 4-methyl-2-propyl-1,3-dioxolane was reported. It has been demonstrated that activated carbon supported tungstosilicic acid is an excellent catalyst. Various factors involved in these reactions were investigated. The optimum conditions found were: molar ratio of aldehyde/ketone to glycol is 1/1.5, mass ratio of the catalyst used to the reactants is 1.0%, and reaction time is 1.0 h. Under these conditions, the yield of 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane is 61.5%, of 2,4-dimethyl- 2-ethoxycarbonylmethyl-1,3-dioxolane is 69.1%, of cyclohexanone ethylene ketal is 74.6%, of cyclohexanone 1,2-propanediol ketal is 80.1%, of butanone ethylene ketal is 69.5%, of butanone 1,2-propanediol ketal is 78.5%, of 2-phenyl-1,3-dioxolane is 56.7%, of 4-methyl-2-phenyl-1,3-dioxolane is 86.2%, of 2-propyl-1,3-dioxolane is 87.5%, of 4-methyl-2-propyl-1,3-dioxolane is 87.9%. 展开更多
关键词 Tungstosilicic acid Aceta KETAL Active carbon CATALYSIS
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