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71.
Jing BI Zongyi MA Shengjin WU Yuxiong LU Hongwei SHEN Institute of Metal Research Academia Sinica Shenyang China 《材料科学技术学报》1993,9(1):61-64
The microstructure and tensile properties of Al_4C_3 dispersion strengthened Al composite fabricatedby reaction milling technique were investigated.It is indicated that the rod-like Al_4C_3 dispersoidshaving a diameter of 0.02-0.03 μm and a length of 0.1-0.3μm are formed by reaction of C with Al,and uniformly distributed in the Al matrix.The interface between Al_4C_3 and Al is clean and theinterfacial bonding is good.The matrix consists of the subgrains which have the size of 0.3-0.4μm,and most of the Al_4C_3 dispersoids are distributed on the subgrain boundaries.The 11 vol.-%Al_4C_3/Al composite exhibits an UTS (ultimate tensile strength) of 400 MPa and anelongation-to-failure of 8.0%. 相似文献
72.
超细Fe3O4粒子表面包覆酞菁钴性质研究 总被引:3,自引:1,他引:2
本文研究了合成载氧体的金属有机化学液相淀积法制造工艺,所得产物经TEM、XPS、Moss-bauer谱和B-H仪等手段,研究了它的结构和磁性能。实验表明,酞青钴以薄层形式包覆在Fe_3O_4的表面,封闭了Fe_3O_4的表面孔洞,稳定了Fe_3O_4的物相,增强了磁性能。 相似文献
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Shizuo Arichi Noriyuki Sakamoto Shozo Himuro Mayumi Miki Masafumi Yoshida 《Polymer》1985,26(8):1175-1180
In order to obtain the additional data concerning the unperturbed dimension of poly-4-substituted styrene, light scattering measurements are performed on the twenty-two fractions with molecular weight of (0.91–352)·104 of poly(4-acetoxystyrene) in dioxan at 25°C, from which the molecular weight obtained was found easily to be evaluated with the gel permeation chromatography using THF. Phase separation experiments for this polymer indicate that the theta state is attained in isopropyl acetate at 19.7°C and butyl acetate at 26.8°C. By making viscosity measurements at that state, the value of KΘ is directly evaluated as 5.4·10?4 dl g?1. The limiting viscosity number is also obtained in good solvents, THF and dioxan, at 25°C and constants of the Mark-Houwink-Sakurada equation in each solvent are determined. Further, approximately the same KΘ as above is obtained from these data with the Stockmayer-Fixman plot. The calculated value of steric factor, 2.37, on this polymer may be plausible, compared with those of polyvinylaromatic derivatives. 相似文献
77.
报导了新型鞣剂 7-羟基全氢化唑并嗪 (以下简称 OX- Z)的合成方法。试验确定合成的最佳条件为 :在氮气保护下 ,将等摩尔量的二乙醇胺在 10℃水浴中缓慢滴入乙二醛中 ,滴加时间 0 .5 h,在 2 0℃水浴中继续反应 1.5 h,产率为 6 2 .9%。 OX- Z对浸酸绵羊皮单独鞣制 ,可使收缩温度升高到 87℃。最佳鞣制条件为 :p H10 .0 ,OX- Z用量 5 % ,鞣制时间 8h。在对 OX- Z与皮胶原的结合类型的研究中证明它们之间是以化学键结合的。 相似文献
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Two commercial Pt modified aluminide coatings (RT22 and MDC150L) on the same single crystal Ni-based superalloy (CMSX-4) were studied by: scanning electron microscopy; transmission electron microscopy; energy dispersive X-ray spectrometry; and gravimetry. The RT22 coating is an inward grown coating (high activity), while MDC150L is produced by outward growth (low activity). Samples were oxidised in still laboratory air at 1050 °C for various times up to 2000 h. It was found that the outward grown coating produced a slower growing oxide that was more spallation resistant. Several possible reasons for this were identified including: coating purity; coating surface topography; and ductile to brittle transition temperature. The microstructural differences between the two coatings in the as-coated condition were investigated and the development of their microstructure during heat treatment was described. A model for coating growth during heat treatment was proposed. 相似文献
80.
Sung-Eun Lee 《Journal of Stored Products Research》2002,38(2):157-166
The fumigant toxicities of lavender and ylang-ylang essential oils were tested against a chlorpyrifos-methyl resistant strain (QVOS102) and an insecticide-susceptible reference strain (VOS48) of the saw-toothed grain beetle, Oryzaephilus surinamensis L. (Coleoptera: Silvanidae). The resistant strain showed 1.3- and 1.6-fold higher tolerance against lavender and ylang-ylang fumigation toxicity, respectively, relative to the susceptible strain. LT50 values calculated as the time to attain 50% mortality of tested insects during fumigation were determined at two different concentrations. At 15 μl/l of air, QVOS102 had 2.9- and 1.4-fold higher LT50 values for lavender and ylang-ylang fumigation toxicity, respectively, than VOS48. At 200 μl/l air, QVOS102 had 6.4- and 2.9-fold higher LT50 values for lavender and ylang-ylang fumigation toxicity, respectively, than VOS48. Piperonyl butoxide, a potential inhibitor of cytochrome P450-dependent monooxygenase, increased fumigant toxicities of the two essential oils against QVOS102. The enhanced tolerance for the essential oil may have resulted from the enhancement of detoxifying enzymes associated with insecticide resistance. 相似文献