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671.
含镍碳化硅复合材料的干摩擦特性 总被引:7,自引:2,他引:7
采用销-盘摩擦磨损试验机,在15~600℃范围内,对反应烧结碳化硅(Si/SiC)及含镍碳化硅(Si/SiC-Ni)复合材料的干摩擦性能进行了研究,结果表明,Ni使Si/SiC复合材料的摩擦学性能得到改善,且SiC的粒度越小,Si/SiC-Ni复合材料的自润滑性能越好。同时通过对磨屑的X射线相分析和磨损表面形貌与成分的扫描同镜/能谱分析,考察了Si/SiC和Si/SiC/Ni复合材料的干摩擦过程。 相似文献
672.
673.
Koki Fujimura Dr. Yoshihiro Ueda Dr. Yousuke Yamaoka Prof. Kiyosei Takasu Prof. Takeo Kawabata 《Angewandte Chemie (International ed. in English)》2023,62(30):e202303078
A method for rotaxane synthesis by enlargement of the size of the terminal phenol group of the axle component by aromatic bromination has been developed. This method may be regarded as an end-capping strategy involving the swelling of the phenol group at the axle terminal. The advantages of the present strategy include: ready availability of axle components with a variety of swelling precursors, wide product scope (19 examples given including a [3]rotaxane), mild conditions for the swelling process, rich potential for the derivatization of the brominated rotaxanes, and possible release of the axle component by degradative dethreading of the thermally stable brominated rotaxanes under the basic conditions. 相似文献
674.
《印度化学会志》2023,100(5):100976
Cyclodextrins (CDs) are cyclic oligosaccharides made up of d-glucose units connected by 1,4-glucosidic linkages. β-CD is a cyclical starch derivative containing seven glucopyranose units. β-CD derivatives have characteristic property of larger surface area, robust mechanical strength, high surface to volume ratio, electrical and optical properties for analyte determination, good dispersion, easy removal of the template, surface modification, functionalization and handling capacity. In this work, an attempt is made to prepare succinyl-β-CD-acrylamide (S-β-CD-AA) copolymer and β-CD-malic anhydride (β-CD-MAH) copolymer. For the synthesis of S-β-CD-AA, S-β-CD derivative is prepared and further, acrylamide (AA) along with cross-linker undergoes free radical copolymerization for the formation of gel like product. The degree of succinylation (DS) of β-CD derivative is estimated. S-β-CD-AA copolymer showed potential swelling, and deswelling characteristic. Another copolymer is prepared from β-CD malic anhydride derivative. Further, the derivative is treated with cellulose and ethylene diamine tetra acetate (EDTA) to form β-CD-MAH copolymer. The two derivatives are characterized by several techniques. Thermal stability of these copolymers is estimated with the help of thermogravimetric analysis. The basic characterization of the presence of functional groups is done using UV–visible spectroscopy, and infrared spectroscopy. The elemental analysis helped to estimate C, H, N, S in the synthesized compounds. The surface morphology characterization is done with the help of scanning electron microscopy. X-ray diffraction analysis helped in determination of crystal structure of β-CD-MAH. β-CD derivatives prepared may be potential candidate to prepare inclusion complex, in drug delivery, drug loading and several similar applications. 相似文献