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51.
52.
ResearchonReactivitiesofMoCluster.ASelectiveSubstitutionReactionoftheBridging(dtp)LigandandStructureofTetranuclearMolybdenumC... 相似文献
53.
54.
Brena B Zhuang GV Augustsson A Liu G Nordgren J Guo JH Ross PN Luo Y 《The journal of physical chemistry. B》2005,109(16):7907-7914
The electronic structure of pure poly(ethylene oxide) (PEO) for four different polymeric chain conformations has been studied by Hartree-Fock (HF) and density functional theory (DFT) through the analysis of their valence band photoelectron spectroscopy (VB-PES), X-ray emission spectroscopy (XES), and resonant inelastic X-ray scattering (RIXS). It is shown that the valence band of PEO presents specific conformation dependence, which can be used as a fingerprint of the polymeric structures. The calculated spectra have been compared with experimental results for PEO powder. 相似文献
55.
物理老化实质上是聚合物材料在 Tg 以下存放过程中 ,其凝聚态结构通过链段或更小运动单元的运动 ,从热力学非平衡态向平衡态过渡的一个结构弛豫过程[1] .在这一过程中 ,聚合物的密度、自由体积、焓、熵和力学性质随温度和时间产生变化 .因为银纹化是聚合物的特性 ,所以银纹化也将随结构回复过程而产生变化 .有关物理老化对聚合物银纹化的影响尚未得出一致的结论 [2~ 4 ] .聚苯基单醚喹啉 (结构见 Scheme1 )是一种高性能的芳杂环聚合物 [5] ,它可以在比较苛刻的条件下作为绝缘材料和膜材料使用 .有关这类高性能的芳杂环聚合物的物理老化… 相似文献
56.
Kun Zhao Shuqi Zhuang Zhu Chang Haiyan Songm Liming Dai Pingang He Yuzhi Fang 《Electroanalysis》2007,19(10):1069-1074
A sensitive amperometric glucose biosensor based on platinum nanoparticles (PtNPs) combined aligned carbon nanotubes (ACNTs) electrode was investigated. PtNPs which can enhance the electrocatalytic activity of the electrode for electrooxidating hydrogen peroxide by enzymatic reaction were electrocrystallized on 4‐aminobenzene monolayer‐grafted ACNTs electrode by potential‐step method. These PtNPs combined ACNTs' (PtNPs/ACNTs) surfaces were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The highly dispersed PtNPs on ACNTs can be obtained. The enzyme electrode exhibits excellent response performance to glucose with linear range from 1×10?5–7×10?3 mol L?1 and fast response time within 5 s. Furthermore, this glucose biosensor also has good reproducibility. It is demonstrated that the PtNPs/ACNTs electrode with high electrocatalytic activity is a suitable basic electrode for preparing enzyme electrodes. 相似文献
57.
Zhuang Hong Cheng Tiexin Bi Yingli Zhou Guangdong Zhen Kaiji 《Reaction Kinetics and Catalysis Letters》2004,81(1):13-20
Factors (reaction temperature, reaction time, flow rate of oxygen, amount of catalyst, etc.) influencing the catalytic properties of Co3O4/SiO2catalyst in the oxidation octadecan-1-ol to octadecanoic acid were investigated. The catalysts were characterized by means of XRD, FT-IR and N2-adsorption. The experimental results indicate that under the optimal condition the selectivity to octadecanoic acid reached 97.5 % over 5 % Co3O4/SiO2 catalyst.This revised version was published online in December 2005 with corrections to the Cover Date. 相似文献
58.
J. Zhuang W. Kunnmann L.M. Corliss J.M. Hastings R.O. Moyer 《Journal of solid state chemistry》1983,48(1):117-120
A powder neutron diffraction study of Eu1532IrD5 has shown it to be isostructural with Sr2IrD5 at room temperature. Unlike the latter compound, it does not undergo a deuterium-ordering transition at low temperatures. Magnetic scattering at helium temperatures confirms the suggestion that it becomes ferromagnetic below 20 K with a moment corresponding to that of divalent europium. 相似文献
59.
铜在HOPG上电沉积过程的现场ECSTM研究 总被引:3,自引:1,他引:3
用自制的电化学扫描隧道显微镜(ECSTM)现场研究Cu在HOPG上的电沉积过程.结果表明Cu在HOPG上的电沉积为三维成核的过程.当电位较低或Cu2+离子浓度较低时,铜在本体金属生长主要沿着台阶方向.过电位较高时,铜的成核数目增加,沉积层的晶粒有所细化.同时,非现场ECSTM比较研究表明,STM针尖对针尖局部区域的电沉积起屏蔽作用,针尖所在区域Cu的沉积速度比其它区域明显减小 相似文献
60.
In the crystalline N,N′-dimethylated uracil derivatives 2a , b , the kinetically stabilized enol group forms an H-bond with O? C(4), as demonstrated by increased shielding of specifically labelled 2a and 2b in the 17O-NMR spectra (Δδ(17O)(C(4)—O) ? ?30 ppm); absence of dilution and solvent effects show that the H-bridge is intra-molecular, forming an eight-membered chelate ring. The (apparent) shielding effect Δδ(17O) in 2a, b is larger than that in salicylamide. The strong H-bond explains why the enols 2 , in spite of the absence of steric hindrance, are kinetically stabilized. 相似文献