W.J. Park
,
S. Ahn
,
R. Schmees
,
and Nack J. Kim(1)(Center for Advaned Aerospace Materials
,
POSTECH. Pohang 790-784
,
Korea )2)(Research Institute of industrial Science & Technology
,
Pohang 790-600
,
Korea )3)(Pratt and Whitney
,
West Palm Beach
,
FL
,
USA Manuscript received 26 August 1996)
金属学报(英文版)
The effects of additions of Ti and W on microstructure and mechanical properties of rapidly solidified Al-Fe-V-Si alloys were investigated. Alloy powders were produced by the centrifugal rotary atomization process. After atomization, powders were screened to various mesh sizes to see the effect of powder size on the mechanical properties.These Powders were consolidated into billets using conventional powder metallurgy process, and then extruded into bar form.Microstructural analysis shows that the W addition results in the heterogeneous microstructure.On the other hand, the Ti addition refines the microstructure.Alloy containing both Ti and W has the highest thermal stability of the dispersoid. These variations in the microstructure are well reflected in the mechanical properties in that the Ti containtng alloys (with or without W) have the higher strength and ductility than the W containing alloy. It also shows that the alloys made of the coarser powders have better combinations of strength and ductility than those made of the finer powders.
关键词:
:rapid solidification
,
null
,
null
材料科学技术（英文）
Constant load tests in NS4 solution purged with N(2)-5%CO(2) gas mixture were conducted on American Petroleum Institute (API) X80 pipeline steel applied in the 2nd West-East Gas Pipeline project with and without preload. The results show that cracks could initiate and propagate in X80 pipeline steel in near-neutral pH environment under a constant load condition. The life of crack initiation and propagation increased with decreasing applied stress. Preload did not change its corrosion behavior obviously. However, preload reduced the time for crack initiation.
关键词:
Stress corrosion cracking;X80 pipeline steel;Near-neutral pH solution;Preload;soil environment;groundwater;initiation;behavior
葛志强
,
王莹
中国稀土学报
为了探究培养生长不同时期的红豆杉细胞对Ce4+应答差异的机制,采用west-Blot免疫印迹法考察了1 mmol·L-1 Ce4+对培养不同时期的红豆杉细胞的细胞外信号调节蛋白激酶磷酸化(p-ERK-like)的表达变化.结果发现,悬浮培养的红豆杉细胞基础p-ERK-like的表达在整个培养周期中呈"M"型变化,分别在培养第五天和第二十一天出现两个高峰,而培养第十一天达到低谷,仅为参比值的77%.在培养的不同时间点应用Ce4+诱导后,细胞的最大p-ERK-like表达量以及到达最大量所需的时间表现出显著的差异,培养第十一天的细胞经Ce4+诱导后其p-ERK-like表达速率达高峰.结果表明,处于不同培养时期的红豆杉细胞其p-ERK-like表达存在显著差异,这可能是导致不同培养时期细胞对Ce4+产生不同应答效应的一个因素.
关键词:
铈
,
ERK-like激酶
,
红豆杉细胞
,
悬浮培养
,
稀土
