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排序方式: 共有414条查询结果,搜索用时 15 毫秒
411.
Hidekazu Tanaka Yumi Takeuchi Tatsuo Ishikawa Takenori Nakayama 《Corrosion Science》2011,(8):2502-2507
To simulate the atmospheric corrosion of steels galvanized with Zn under different conditions, artificial zinc rusts of basic zinc salt (BZS) were prepared by hydrolyzing ZnO particles in aqueous solutions including ZnCl2, ZnSO4 and Zn(NO3)2. In ZnCl2–ZnSO4, ZnSO4–Zn(NO3)2 and ZnCl2–Zn(NO3)2–ZnSO4 systems, zinc hydroxysulfate (Zn4(OH)6(SO4)·nH2O) was formed while zinc hydroxychloride (Zn5(OH)8Cl2·H2O) was generated in ZnCl2–Zn(NO3)2 system. Zinc hydroxynitrate (Zn5(OH)8(NO3)2·2H2O) was yielded in only Zn(NO3)2 system. All the formed artificial zinc rusts were hexagonal plate particles. These results suggest that SOx is the most effective corrosive gas on the formation of BZS rusts on galvanized steel. 相似文献
412.
Nobuko Hanada Takayuki Ichikawa Satoshi Hino Hironobu Fujii 《Journal of Alloys and Compounds》2006,420(1-2):46-49
Kinetics of hydrogen absorption and desorption reactions was investigated on the MgH2 composite doped with 1 mol% Nb2O5 as a catalyst by ballmilling. The composite after dehydrogenation at 200 °C absorbed gaseous hydrogen of 4.5 mass% even at room temperature under lower pressure than 1 MPa within 15 s and finally its capacity reached more than 5 mass%. On the other hand, the catalyzed MgH2 after rehydrogenation desorbed 6 mass% hydrogen at 160 °C under purified He flow, which followed the first order reaction. From the Kissinger plot, the activation energy for hydrogen desorption was estimated to be 71 kJ/mol H2, indicating the product was significantly activated due to the catalytic effect of Nb2O5. 相似文献
413.
Glass milling is discussed with influences of tool inclination on brittle fracture. Cutting tests are performed to observe surfaces in the up-cut and the down-cut processes with a ball end mill inclined in the feed direction of the cutter. Brittle fracture occurs in the down-cut process at high feed rates. Then the machined surfaces in cutting with the ball end mills tilted in the vertical plane with respect to the feed direction are associated with those of the up-cut and the down-cut processes. The cutting forces are also measured to discuss brittle fracture with the change of the undeformed chip thickness. The scratches on the surface finished with the tilted ball end mill are shown in an analytical model with a notched edge shape. The maximum feed rates at which brittle fracture does not occur are shown with the tool inclination in the cutting tests. 相似文献
414.
Noriyuki Yonezawa Tsutomu Namie Tomohide Ikezaki Tetsuo Hino Hiroyuki Nakamura Yoshimi Tokita Ryoichi Katakai 《Reactive and Functional Polymers》1996,30(1-3):261-268
Bisfunctional biphenylene monomers were designed, synthesized, and inspected as building blocks for aromatic polyketone synthesis. Starting from 2,2′-dimethoxybiphenylene (1), a highly activated acyl-acceptant biphenylene monomer affording high molecular weight polyketones, two types of biphenylene monomers were developed: 5,5′-bis(3[4]-chlorobenzoyl)-2,2′-dimethoxybiphenylenes (6) which readily gave the corresponding polyketones by nickel-catalyzed aromatic coupling polymerization and 2,2′-bis(trifluoromethyl)-4,4′-biphenylenedicarboxylic acid (27) which reacted with biphenylene 1 in P2O5---CH3SO3H to give the corresponding fluorinated aromatic polyketone, selectively. The related model reactions for both monomer synthesis and polymerization were also investigated. 相似文献