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排序方式: 共有7894条查询结果,搜索用时 250 毫秒
311.
QinZHAO RuoYUAN ChangLiMO YaQinCHAI XiaZHONG 《中国化学快报》2004,15(2):208-211
Naphthol green B was used, for the first time, as a new mediator in an amperometric glucose biosensor. It is a good mediator, promoting electron transfer from glucose oxidase to graphite electrode. The biosensor shows high sensitivity to glucose at low potential with response time of 30 seconds. The linear range is from 1.5 to 18μmol/L glucose with detection limit of 0.5μmol/L glucose. 相似文献
312.
YAO Tian-Ming YOU Xiao-ZengCoordination Chemistry Institute State Key Laboratory of Coordination Chemistry Nanjing University Nanjing ChinaYANG Qing-ChuanChemistry Department Beijing University Beijing China 《中国化学》1994,12(3):248-257
The reaction of CuCl2-2H2O or NiCl2.6H2O with K2(C5H6S4) [potassium salt of 6,7-dihydro-5H-1,4-dithiepin-2,3-dithiolate] under nitrogen atmosphere resulted in the isolation of [Cu(C5H6S4)2]- or [Ni(C5H6S4)2]- as the tetrabutylammonium salt. Both complexes show characteristic IR and UV-Vis absorptions of transition metal dithiolenes. Cyclic voltammograms contain two waves indicating a two step electrochemical procedure [M(C5H6S4)2]0 = [M(C5H6S4)2]1-= [M(C5H6S4)2]2-. Single crystal structure study has been carried out on the nickel complex. Crystal of [Bu4N][Ni(C5H6S4)2] belongs to monoclinic space group P21/c with a=17.576(5), 6=10.883(2), c=17.773(4) A,B=91.07(2)0, Z=4, and o(calcd.)=1.348 g/cm3. Final result is R=0.059 for 2959 reflections. The NiS4 core exhibits square planar coordination with average Ni-S bond length of 2.134(5) A. There are not anion pairs in crystal. The anions stack along a and c axes while the cations intercalate in them. The nearest S-S contact is 4.429 A. The solid powder ESR s 相似文献
313.
报道了一种新的杂多化合物[HN(C_2H_5)_3]_4-[Mo_3~VMo_6~(VI)V_7~(IV)O_(40)(PO_4)]·2[N(C_2H_5)_3]的合成,并用元素分析、EPR、IR谱、及X--射线单晶衍射等手段进行了表征。结果表明,该杂多酸盐属于单斜晶系,空间群P21/n,a=14.0841(3),b=14.2505(3),c=19.6089(3)?b=94.213(1),V=3925.0(1)?,Z=2,Dc=2.171g/cm3,Mr=2566.18,m=2.284mm-1,F(000)=2516,R=0.0477,wR=0.0945.杂多阴离子是1个16金属笼状物,笼中心包含1个PO4四面体客体。 相似文献
314.
315.
316.
Dan Zhu Yi-xiang Cheng Xiao-wei Zou Ling-wu Chen Jin-feng Song Zhi-liu Wang College of Chemistry Chemical Engineering Nanjing University Nanjing China 《高分子科学》2006,(6)
Chiral polymer was synthesized by the polymerization of (R)-6,6'-bistributylstannyl-2,2'-binaphtho-20-crown-6 (M-1) with 1,4-dibromo-2,3-bisbutoxy-naphthyl (M-2) by Pd(PPh3)4 catalyzed Stille coupling reaction. Both monomer and polymer were analyzed by NMR, MS, FT-IR, UV, polarimetry, DSC-TGA, CD, fluorescent spectroscopy and GPC. The major difference between monomer and polymer is that a long wavelength Cotton Effect was observed for the polymer due to its more extended conjugation in the repeating unit and a highly rigid backbone in the polymer chain. Polymer has strong blue fluorescence due to the efficient energy migration from the extended n-electronic structure of the repeating unit of the polymer to the chiral binaphthyl core and is expected to have potential application in the materials of fluorescent sensors and chiral chromatographic packing for resolution of racemic amino acid. 相似文献
317.
DNA分子在气液界面的组装相变特性及其LB膜结构研究 总被引:5,自引:0,他引:5
对十八胺与DNA在气液界面上组装及其相变过程进行了研究,利用AFM观察了不 同压力下转移的DNA复合LB膜结构。发现在低表面压时,DNA复合单分子膜表现为技 术发散的分形结构;随着压力的升高,DNA复合膜逐渐由紧密的网状排布结构变为 团聚的块状和团簇结构。表明通过调节膜压,可使膜内DNA分子的构象发生大的变 化,从而生成具有特定形态的二维纳米图案。这种具有特殊形态和结构的DNA LB膜 可望为合成新型生物纳米结构有序功能体系提供模板。 相似文献
318.
An eficient liquid-phase synthesis of isoxazolines through a 1,3-dipolar cycloaddition is described.Soluble polymer-supported acrylate reacted with nitrile oxides generated in-situ,followed by cleavage from the support giving corresponding isoxazolines in high yields and excellent purities. 相似文献
319.
HONG Gong-Yi LI Le-MinCollege of Chemistry Molecular Engineering State Key Laboratory of Rare Earth Materials Chemistry Applications Peking University Beijing China 《中国化学》1996,14(4):289-296
Several numerical integration schemes for the evaluation of matrix elements in density functional theory calculations have been studied and compared by computational practice. The best scheme was found to be the combination of the atomic partition function proposed by Becke with the scaled generalized Gauss-Laguerre quadrature formula for radial integration suggested by Yang, which achieve the highest convergence rate to the numerical integration. With the same number of integration points, the accuracy of the calculated results by this scheme is higher by 1 to 2 orders of magnitudes than that by other schemes. The reason for achieving higher accuracy by this scheme has been proposed preliminarily. 相似文献
320.
CAI Shu-Hui LI Jun LIU Chun-WanFujian Institute of Research on the Structure of Matter Chinese Academy of Sciences State Key Laboratory of Structural Chemistry Fuzhou Fujian China 《中国化学》1994,12(5):385-391
The band structures of several analogous superconducting A-15 type solid compounds, Nb3X (X=Si, Ge, Sn, Pb), have been calculated by use of the tight-binding method within the Extended Huckel approximation (EHT). By analysis of their energy bands, densities of states and crystal orbital overlap populations, the dependence of the superconducting transition temperatures (Tc) on the electronic structures and bondings is qualitatively elucidated. 相似文献