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61.
62.
本文简要阐述了北化院BCS01和上海院SLC-S两种国产气相聚乙烯浆液催化剂的性能、催化剂结构,在Unipol聚乙烯工业装置上应用结果,以及和进口同类催化剂UCAT-J的性能比较。 相似文献
63.
Gregory N. Morscher Hee Mann Yun James A. DiCarlo 《Journal of the American Ceramic Society》2007,90(10):3185-3193
The tensile mechanical properties of ceramic matrix composites (CMC) in directions off the primary axes of the reinforcing fibers are important for the architectural design of CMC components that are subjected to multiaxial stress states. In this study, two-dimensional (2D)-woven melt-infiltrated (MI) SiC/SiC composite panels with balanced fiber content in the 0° and 90° directions were tensile loaded in-plane in the 0° direction and at 45° to this direction. In addition, a 2D triaxially braided MI SiC/SiC composite panel with a higher fiber content in the ±67° bias directions compared with the axial direction was tensile loaded perpendicular to the axial direction tows (i.e., 23° from the bias fibers). Stress–strain behavior, acoustic emission, and optical microscopy were used to quantify stress-dependent matrix cracking and ultimate strength in the panels. It was observed that both off-axis-loaded panels displayed higher composite onset stresses for through-thickness matrix cracking than the 2D-woven 0/90 panels loaded in the primary 0° direction. These improvements for off-axis cracking strength can in part be attributed to higher effective fiber fractions in the loading direction, which in turn reduces internal stresses on weak regions in the architecture, e.g., minicomposite tows oriented normal to the loading direction and/or critical flaws in the matrix for a given composite stress. Both off-axis-oriented panels also showed relatively good ultimate tensile strength when compared with other off-axis-oriented composites in the literature, both on an absolute strength basis as well as when normalized by the average fiber strength within the composites. Initial implications are discussed for constituent and architecture design to improve the directional cracking of SiC/SiC CMC components with MI matrices. 相似文献
64.
系统研究了苏州高岭土碳热还原氮化合成SiAlON过程在不同温度下的相变。对试样的XRD、SEM以及EDXA分析结果表明 ,1 30 0℃之前 ,试样中没有氮化物生成 ,物相为莫来石、石英和方石英 ;1 30 0℃时 ,高岭土开始发生氮化反应 ,生成过渡型SiAlON和β SiAlON。此时 ,石英和方石英相基本消失 ;1 4 0 0℃时 ,过渡型SiAlON、β SiAlON和X SiAlON三相共存 ,β SiAlON有所增多并有少量刚玉相生成 ;从 1 4 50℃到 1 550℃ ,Z值为 3的β SiAlON成为惟一的氮化产物 ,与少量SiC和刚玉相并存。莫来石在 1 50 0℃时完全消失 相似文献
65.
66.
以DRC为催化剂,在无溶剂条件下,通过氢化松香与乙醇的直接酯化反应合成氢化松香乙酯。探索了反应温度、催化剂用量、反应时间、物料配比等因素对反应酯化率的影响,确定最佳反应条件为:反应温度180℃,催化剂用量为原料氢化松香质量的6%,反应时间6h,醇与酸的摩尔比为3∶1。在最佳条件下酯化率达92.2%。还探讨了用阴离子交换树脂柱层析分离纯化氢化松香乙酯粗产物的方法。此外,利用红外光谱对氢化松香乙酯精制产物进行了表征;用GC-MS分别对氢化松香乙酯粗产物及其精制产物进行了定性和定量分析,比较了柱层析前后化学组成的变化。 相似文献
67.
Fushe-Kruje水泥厂项目位于距阿尔巴尼亚首都地拉那市28公里处,是由黎巴嫩SEAMENT集团投资兴建的.是迄今阿尔巴尼亚最大的外商投资项目,设计能力为3300t/d新型干法水泥熟料生产线,是全套生产线由我公司设计、制造成套、施工、安装、调试及试生产的总承包项目。 相似文献
68.
The aluminated sepiolite, obtained by alkaline treatment with KAlO2, as well as the silver-exchanged aluminated sepiolite were tested in ethanol conversion. The reactions were performed at 280°C and with 50 Torr of ethanol in He. After the alumination through KA1O2, ethanol dehydrogenation and ethanol dehydration resulted from the Lewis acidity. The dispersion of silver led to a bifunctional catalytic system and the overall catalytic activity and the selectivity towards the acetaldehyde production increased. As a result of the Prins reaction, a significant yield in butadiene was observed. 相似文献
69.
The study of collective user behaviours in social networking sites has become an increasing important topic in social media mining. Understanding such behaviours has its potential to extract actionable patterns that can be beneficial to develop effective marketing strategies, optimise user experiences and maximise website revenues. With the rapid development of micro-blogging, Twitter has become a richer source of intelligence that can be used to study collective user behaviour, due to its efficient and meaningful user-to-user interactions. However, the classical statistical methods have some drawbacks in bridging the gap between user-generated data and human analysts who mostly use linguistic terms to analyse data and model/summarise knowledge learned. To address this gap, this work proposes a new approach, which employs the mass assignment theory-based fuzzy association rules algorithm (MASS-FARM), for the first time, to extract useful interaction behaviour of Twitter users. The influential factors (including activity time, number of friends/followers and the number of tweets) are represented as fuzzy granules, and the associations amongst are studied by employing MASS-FARM. The collective user behaviours are analysed in the Reply category and the Non-Reply category, respectively. The applicability and usefulness of the proposed method are demonstrated via an empirical study on a collected Twitter data set. The derived results are also discussed and compared with existing works. 相似文献
70.
Grace Y. Sun 《Lipids》1979,14(11):918-924
The phospholipid composition and their acyl group profiles from subcellular fractions of guinea pig adrenal gland and the
same fractions from the cortex and medulla of the bovine gland were compared. The phospholipids of guinea pig adrenal were
enriched in diacyl-glycerophosphocholines (GPC) which comprised over 50% of the total phospholipids, but the proportions of
ethanolamine and choline plasmalogens, sphingomyelin and diacyl-glycerophosphoserine (GPS) were lower in guinea pig adrenals
as compared to the bovine adrenals. In the bovine adrenal, sphingomyelin and diacyl-GPS were enriched in the medulla, whereas
diacyl-glycerophosphoinositol (GPI) were enriched in the cortex. Although lysolecithin was present (up to 4.5%) in the bovine
adrenal, only trace amounts of this lipid were detected in the guinea pig adrenal. Characteristic acyl group profiles were
found associated with each type of the phosphoglycerides in adrenal membranes. However, acyl group profiles of the phosphoglycerides
were not greatly different either between the bovine and guinea pig adrenal or with respect to the type of subcellular membranes
isolated. Diacyl-GPC were enriched in 16∶0 and 18∶1, but also contained considerable amounts of 18∶0, 18∶2 and 20∶4. Diacyl-GPE
were enriched in 18∶0, 18∶1 and 20∶4, while diacyl-GPI, diacyl-GPS, as well as alkenylacyl-GPE, were enriched in 20∶4. The
lysolecithin from bovine adrenal membranes contained mainly 16∶0, 18∶0 and 18∶1 with only trace amounts of the polyunsaturated
fatty acids. Other polyunsaturated fatty acids, such as 22∶4 and 22∶6, are apparently not prominent in the phosphoglycerides
from either the bovine or the guinea pig adrenal gland. 相似文献