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111.
Nanoscale Co3O4 particles were doped into MgB2 tapes with the aim of developing superconducting wires with high-current-carrying capacity. Fe-sheathed MgB2 tapes with a mono-core were prepared using the in situ powder-in-tube (PIT) process with the addition of 0.2–1.0 mol% Co3O4. The critical temperature decreased monotonically with an increasing amount of doped Co3O4 particles for all heat-treatment temperatures from 600 to 900 °C. However, the transport critical current density (Jc) at 4.2 K varied with the heat-treatment temperatures. The Jc values in magnetic fields ranging from 7 to 12 T decreased monotonically with increasing Co3O4 doping level for a heat-treatment temperature of 600 °C. In contrast, some improvements on the Jc values of the Co3O4 doped tapes were observed in the magnetic fields below 10 T for 700 and 800 °C. Furthermore, Jc values in all the fields measured increased as the Co3O4 doping level increase from 0 to 1 mol% for 900 °C. This heat-treatment temperature dependence of the Jc values could be explained in terms of the heat-treatment temperature dependence of the irreversibility field with Co3O4 doping. 相似文献
112.
Shinichi Nagai Takamasa Miyachi Tetsu Nakane Taisei Ueda Yasuhiro Uozumi 《Journal of heterocyclic chemistry》2001,38(2):379-381
Starting from 3‐chloro‐5,8‐methanoquinazoline 1 and 3‐chloro‐bornano[1,2,4]triazine 7 , the novel 5,8‐methanoquinazolines 5a‐b and bornano[1,2,4]triazines 10a‐b fused with imidazole and pyrimidine were prepared. None of these compounds showed any satisfactory central nervous system stimulant activities. 相似文献
113.
Itsuo Mori Yoshikazu Fujita Minako Toyoda Michiyo Kashiwagi 《Fresenius' Journal of Analytical Chemistry》1991,340(1):57-59
Application of xanthene derivatives in analytical chemistry. Part LXXXVIII. Part LXXXVII see ref. [1] 相似文献
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The tricyclic core of cyathins has been synthesized using a Brook rearrangement-mediated [3 + 4] annulation that we previously developed. 相似文献
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117.
Copolymerization of ethylene and 1,5-hexadiene (HD) by zirconocene catalysts proceeded via cyclization-addition mechanism to form 1,3-didsubstituted cyclopentane structure in the polyethylene chain. The 1,3-cyclopentane structure was found to be taken in the crystalline structure of polyethylene (isomorphism) by partially chainging the trans zigzag chain into gauche conformation, thereby, inducing a transformation of orthorhombic crystal to pseudohexagonal crystal. Copolymerization of ethylene and cyclopentene (CPE) by zirconocene catalysts yielded copolymers having 1,2-disubstituted cyclopentane structure in the polyethylene chain. The 1,2-cyclopentane structure was not taken into the crystalline structure of polyethylene. The melting point (Tm) and the crystallinity (Xc) of polyethylene decreased by copolymerization of HD or CPE, and the Tm- and Xc-decreasing effect of CPE was stronger than HD. For copolymers of propylene and HD or CPE obtained with isospecific zirconocene catalyst, the isomorphism was not ovserved. 相似文献
118.