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161.
Color reactions are used to determine ruthenium utilizing spectrophotometer, but the process need high temperature, long time pyrogenation and miscellaneous extraction and it contaminates the enviroment. As the sensitive degree and simple apparatus of catalyst kinetics analytical method, it was extensively attentcd. The fundmental principle means to determinn a certain chemistry reaction rate accelerated by homogeneous catalyst and determine substantial content using the function of the numerical value of of its and the catalyst concentration. Color acid double azo-reagents (chloro-phosphor group, arsenic group and carboxylic acid group) are sensitive color reagent determining uranium and thorium of lanthanon, but the report is few that it is used to determine ruthenium. Since 1990s, the author studied that the ruthenium was possessed evident catalysis to the fade reaction of oxidant (KIO4, KBrO3) oxidating color acid double azo-reagent in acitidy medium and provided the catalyst kinetics analytical method to determine trace ruthenium.sensitive degree was increased 1 ~2 amount than color reaction. The reaction as:The original concentration of color acid double azo-reagents is A. The instantaneous absorbency after t reaction time is At. In homogeneous catalyst reaction: log(A0/At) = KCRu3+t. Reaction time t is invarible, so log(A0/At) = K' CRu3+t.Color acid double azo-reagents, such as: chlor-azochlorphosphor(CPA-TC),bromic-azochlorphosphor (CPA-TB), DBS-azochlorphosphor(DBS-CPA), DBC-azochlorphosphor (DBC-CPA), DBOK-azochlorpho sphor (DBOK-CPA), p-iodineazochlorphosphor(CPA-PI),p-acetylazochlorphosphor (CPA-PA), azochlorpho sphorⅢ(CPAⅢ), chlor-azoarsenic (TC-AsA),bromic-azoarsenic (TB-AsA), DBS-azoarsenic(DCS-AsA), DCS-azoarsenic(DCS-AsA),azoarsenicⅢ(AsAⅢ), bromicnityrlazoarsenic (DBN-AsA), P-acetylcarboxy lazo-p,P-acetylcarboxylazo, were utilized in catalyst kinetics system. The author obtains the satisfactory results that color acid double azo-rea gents was utilized to determine ruthenium of noble metal mine. 相似文献
162.
用射频磁控溅射方法制备了系列Co/SiO2不连续磁性金属绝缘体多层膜(DMIM) .经研究发现:对[SiO2(2.4 nm)/Co(t)]20体系,在Co层厚度小于2.5 nm时,Co层由连续变为不连续;Co层不连续时,其导电机理为热激发的电子隧穿导电,lnR与T-1/2接近正比关系; 隧道磁电阻(TMR)在Co层厚度为1.4 nm时出现极大值-3%.DMIM 的性质 不仅与磁性金属层厚度密切相关,而且与绝缘层厚度有密切的关系.在固定Co层厚度为 1.9 nm的情况下,研究了TMR随SiO2层厚度的变化
关键词:
不连续磁性金属/绝缘体多层膜
隧道磁电阻效应 相似文献
163.
Qi‐Lu Zhang Xiao‐Yan Ma Guo‐Zheng Liang Xiao‐Hong Qu Yun Huang Shu‐Hui Wang Kai‐Chang Kou 《Journal of Polymer Science.Polymer Physics》2008,46(12):1243-1251
The high‐speed homogeneous shearing method was applied to prepare nanocomposites of cyanate ester (CE) with liquid polyurethane elastomer (PUR) and silica. To investigate the influence of various components on the morphology and properties of the ternary composites, the binary composites of CE/PUR and CE/silica were also involved in this article. The morphology of the cured materials of binary and ternary systems was investigated by transmission electron microscopy (TEM), and the results show that silica nanoparticles were uniformly distributed in the ternary and binary matrix. Phase separation of elastomer in composites was not observed by TEM. FTIR test and dynamic mechanical analysis (DMA) proved that chemical linking was existent between PUR and CE. Scanning electron microscopy examinations and mechanical properties tests were carried out. The results show that ternary composites displayed higher fracture toughness and impact strength compared with most of the binary systems. This suggests that the addition of PUR and nanosilica can synergistically improve the toughness of CE. DMA studies confirmed that the incorporation of silica can increase the storage modulus and Tg for CE and CE/PUR system, since there are a good adhesion and a strong hydrogen bonding between silica and polymers. The thermal property of ternary composites increases with the increase of silica nanoparticle loading. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1243–1251, 2008 相似文献
164.
J. W. Chen Z. Z. Xu T. Q. Xiao P. P. Zhu L. G. Kou Z. J. Wang 《Optics & Laser Technology》1995,27(6):369-373
Aberrations in the reconstruction of images are analysed, aberration elimination methods are discussed and the feasibility of direct image reconstruction from a lensless Fourier transform X-ray hologram with visible light is investigated. 相似文献
165.
C. S. Kou M. H. Wu Fouriers Tseng 《International Journal of Infrared and Millimeter Waves》1997,18(10):1857-1883
To preserve high gain, high efficiency and high power merits of gyroklystron, a gyro-twystron is designed using an electron
beam with α(v⊥/vz) greater than unity. With a multi-cavity section of high gain, the length of the waveguide output section can be made shorter
than the threshold length of the absolute instability without losing total system gain. Numerical simulations are carried
out to analyze a ka-band gyro- twystron consisting of three TE111 mode cavities and an output section of a TE11 mode waveguide. Stability study is performed to ensure the tube without self-excited oscillations. With α=1.5, the 3-dB linear
and saturated gain bandwidth in excess of 2 % can be obtained by stagger tuning for an 80 kV, 3 A electron beam with 5 % axial
velocity spread. The maximum saturated gain is more than 55 dB at 33 % efficiency. By tapering the magnetic field of the last
2 cm of the interaction region, the efficiency can be increased to 43 % without degrading the bandwidth, which corresponds
to an output power of 103 kW. 相似文献
166.
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169.
水解聚丙烯酰胺溶液粘弹特性的研究 总被引:2,自引:0,他引:2
通过锥板测量系统对水解聚丙烯酰胺(HPAM)溶液的粘弹性进行了研究.结果表明, 这种锥板测量系统能较灵敏地检测出溶液粘弹性结构的存在,并得到了聚合物溶液的弹性成份和粘性成份的关系.发现随着HPAM溶液浓度的增大,聚合物溶液的弹性成份起初迅速增大,随后增大的趋势变慢而趋于平缓,在经历一最大值后又略有下降.在剪切速率7773; =0.36 s-1下,超高分子量的HPAM(M=1.65×107)溶液(c = 1.5 g·L-1)具有明显的粘弹特性;随着盐的加入,溶液的粘弹性下降,当盐浓度达到一定值的时候,溶液内部的网络结构遭到破坏,其弹性行为完全消失.对于聚丙烯酰胺(PAAM, M=2.0×105)溶液(c = 2.0 g·L-1)在剪切速率(7773;=0.36~1.36 s-1)范围内没有观察到粘弹行为,只在7773;≥1.65 s-1时,才能观察到微弱的粘弹现象. 相似文献
170.