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141.
三(苄基硫醇)锑的合成及其应用性能 总被引:1,自引:0,他引:1
以苄基硫醇、三氧化二锑 (或三氯化锑 )等为原料 ,研究了三 (苄基硫醇 )锑的最佳合成工艺条件 ,产率分别达到 90 %和 95 %。用元素分析法及红外光谱技术对产品进行了表征 ,热分析技术 (TG和DSC)研究表明 ,含合成产物的聚氯乙烯 (PVC)制品的初始分解温度在 2 2 0℃以上 ,其热分解效应为 1 1 5 5J/g。热老化研究表明 ,当合成产物添加量达 1 5份 (PVC质量为 1 0 0份 )时 ,PVC树脂的热稳定时间为 1 8min(2 0 0℃ ) ,当其与硫醇钡以质量比 3∶1复配时 ,可显著提高PVC制品的长期热稳定性 相似文献
142.
143.
M. -K. Chang E. J. Conkerton D. C. Chapital P. J. Wan O. P. Vadhwa J. M. Spiers 《Journal of the American Oil Chemists' Society》1996,73(2):263-265
Chinese melon (Momordica charantia L.), also known as bitter gourd, is a tropical crop, grown throughout Asian countries for use as food and medicinals. In
1993, four cultivars of Chinese melon were grown in Mississippi and the seeds were collected. Oil contents of the seeds ranged
from 41 to 45% and the oils contained 63–68% eleostearic acid and 22–27% stearic acid. Industrially important tung oil, a
“fast-drying oil” used in paints and varnishes, contains 90% eleostearic and 2–3% stearic acid. The ratio of stearic to eleostearic
in Chinese melon seed oil is ten times greater than that in tung oil. The higher ratio should reduce the rate of drying and
crosslinking and could be advantageous in the paint industry. The defatted meals contained 52–61% protein and would be a good
source of methionine. 相似文献
144.
Effects of Copper Coating on the Crystalline Structure of Fine Barium Titanate Particles 总被引:1,自引:0,他引:1
Xinghua Liu Wan Y. Shih Wei-Heng Shih 《Journal of the American Ceramic Society》1997,80(11):2781-2788
We have investigated the effect of a metal coating—copper—on the tetragonal structure of fine barium titanate (BaTiO3 ) particles. The BaTiO3 particles were synthesized by a sol-gel method and heat treated at temperatures >900°C for various amounts of time before coating. The copper coating was achieved by an electroless coating technique. The transmission electron microscopy micrographs revealed that the coated powder contained fine BaTiO3 particles that were embedded in copper patches. The X-ray diffractometry patterns showed that the copper coating increased the c/a ratio of the fine BaTiO3 particles. For powders that were heat treated at 900°C for 10 h and were initially cubic, the copper coating changed the c/a ratio, from 1 to 1.0034. For powders that were calcined at 900°C for 20 h and were initially tetragonal, the copper coating further enhanced the c/a ratio, from 1.0028 to 1.0043. When the copper-coated BaTiO3 particles were oxidized, the c/a ratio was reduced to a value that was approximately equal to or below that of the uncoated powders. A conductive coating can eliminate the depolarization energy of an insulating polar particle. The fact that the copper coating promoted the polar tetragonal phase but the nonconductive copper-oxide coating did not was consistent with the interpretation that the presence of the cubic phase (nonpolar) in small BaTiO3 particles was caused by the depolarization effect. 相似文献
145.
146.
Lianjun Wang Ting Wu Wan Jiang Jianlin Li Lidong Chen 《Journal of the American Ceramic Society》2006,89(5):1540-1543
A novel method for the preparation of Al2 O3 –TiN nanocomposites was developed. A mixture of TiO2 , AlN, and Ti powder was used as the starting material to synthesize the Al2 O3 –TiN nanocomposite under 60 MPa at 1400°C for 6 min using spark plasma sintering. X-ray diffractometry, scanning electron microscopy, and transmission electron microscopy were used for detailed microstructural analysis. Dense (up to 99%) nanostructured Al2 O3 –TiN composites were successfully fabricated, the average grain size being less than 400 nm. The fracture toughness ( K I C ) and bending strength (σb ) of the nanostructured Al2 O3 –TiN composites reached 4.22±0.20 MPa·m1/2 and 746±28 MPa, respectively. 相似文献
147.
近年来,我国网上银行的业务量增长迅速,越来越多的商务交易通过网银来实现,由于网络存在缺陷,进而导致针对网银的犯罪情态日益严重,网银的安全问题十分突出,这给网络银行的正常运行造成了一定程度的影响,严重损害了网银的根本利益,阻碍了网上银行的稳定、健康发展。本文主要针对我国网银安全问题进行探讨,阐述了我国网银发展的现状,并提出了几点措施,以有效加固网银安全,降低网银的风险,不断推动网上银行的健康发展。 相似文献
148.
综述了银催化剂的发展历史、催化作用机理、制备方法、助催化剂、载体研究进展,并对用于乙烯环氧化反应的银催化剂在不同时期的发展状况、宏观及微观催化作用机理、从原料到催化剂成品的制备过程、数十种金属及非金属助催化剂的助催作用、载体结构及添加组分的改进等方面的最新研究成果作了阐述。 相似文献
149.
150.