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1 INTRODUCTION donor due to the presence of the protonated carboxyl group; (d) it can form short bridges via one car- Coordination polymers are of great interest due to boxylato end or long bridges via the benzene ring[7]. their physical properties and potential applications in We believe that coordination functionality of isoph- functional materials[1~3]. Aromatic polycarboxylic acids thalate can lead to interesting structures. In this com- such as 1,2,4,5-benzenetetracarboxylic acid[4],… 相似文献
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XIAO Guang-Can① 《结构化学》2006,(9)
1 INTRODUCTION The construction and characterizations of low dimensional inorganic/organic hybrid materials have increasingly attracted the interest of chemists duo to their unusual topologies and relevance in a wide range of applications in materials science including transport, magnetic materials, catalysts, and lumi- nescent materials[1]. Among the various families of hybrid functional materials, the family of metal halides is an important one. As a branch of the metal halides, silver(… 相似文献
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YE Ruo-Bai HUANG Chang-Cang ① ZHANG Han-Hui LI Hao-Hong YANG Qi-Yu SUN Rui-Qing 《结构化学》2005,24(6):679-683
1 INTRODUCTION Recently, the organic-inorganic hybrid Ⅳa groupmetal halides with low-dimensional structure haveattracted much attention of chemists and physicistsdue to their particular properties and applications.For example, they are akin to “natural quantum-well”architectures and have tunable excitonic propertiesusually governed by the inorganic substructure andorganic component[1]; they have been applied assome technologically important materials, such assemiconductor materials in … 相似文献
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1 INTRODUCTION Recently, the low-spin square-planar nickel(II) complexes and high-spin octahedral nickel(II) complexes with Schiff base ligands have received much attention in optical materials[1~3]. Some nic- kel(II) complexes are widely used as lubricating oil, rubber industry additives, a fire-resistant additive and fungicide for leather[4~7]. Also, their adducts with nitrogen have attracted broad attention due to their potential applications as organic conductors and magnetic mate… 相似文献
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1 INTRODUCTION The picoloylhydrazide compounds are close to thebiologic environment and can react with microele-ments in organism so as to have antitubercular andantineoplastic activities. However, owing to the exis-tence of amino group, this kind of compounds aretoxic to some extent[1]. In order to decrease theirtoxicity, hydrazone or hydrazide compounds synthe-sized by the condensation reaction of amino and car-bonyl groups have been well studied in recentyears[1~7]. Herein we report t… 相似文献
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1 INTRODUCTION AIDS, in other words, Acquired Immunodefici-encysyndrome, is a viral contagious disease withhigh death rate. However, effective treatment againstit has not appeared so far. At present, about 100kinds of natural compounds that could be extractedfrom natural products or artificially synthesized havebeen found to have anti-HIV activities to some ex-tent. They belong to flavonoid, terpenoid, steroid, cou-marin, peptide, alkaloid etc., respectively. Previousstudies show that… 相似文献
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ZHANG Li① LI Kang-Lan 《结构化学》2008,27(2):230-232
The title Schiff base compound 4-bromo-2-[(3-methylpyridin-2-ylimino)methyl]phenol was prepared and structurally characterized by elemental analysis, IR spectrum, and single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P2 1/n, with a = 4.4870(9), b = 19.953(4), c = 13.860(3)A, β = 93.13(3)°, V = 1239.0(4)A3 Z = 4, Dc = 1.561 g/cm3, C13H11BrN2O2 , Mr = 291.15, p = 3.302 mm-1 and F(000) = 584. The final refinement gave R = 0.0608 and wR = 0.1377 for 1329 observed reflections with I 〉 2σ(I). X-ray diffraction reveals that the non-hydrogen atoms in the compound are nearly coplanar, with the mean deviation of 0.0197A from the plane. The molecule adopts an E configuration about the central C=N functional bond. The compound possesses moderate antimicrobial property. 相似文献
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提出一种新的降维方法, 加权方差估计(WVE), 它包含了切片平均方差估计(SAVE)作为特例. 并且利用Bootstrap方法从WVE中 选择出最优估计, 给出了维数的选择方法. 该最优估计通常远好于已有方法, 比如切片逆回归(SIR)等. 已有的许多方法, 如SIR, SAVE等, 通常对每个 观测给予相同的权来估计中心子空间(CS). 通过引入权函数, WVE根据观测样本距中心子空间的距离, 对不同观测给予不同权重. 权函数使得WVE在很 一般或复杂的情形下有很好的表现, 比如, 回归变量的分布严重偏离椭圆对称分布. 而椭圆对称分布假设是许多方法 的基本假定, 如SIR, SAVE等. 和已有方法相比, WVE对自变量的分布不敏感. 本文建立了WVE的相合 性. 与其他方法的模拟比较表明了WVE的优点. 相似文献
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本文考虑本质位置参数分布族中,参数的Fiducial分布与后验分布的等同问题.首先讨论了如何给出Fiducial分布,分析结果表明以分布函数形式给出Fiducial分布要比密度函数形式合理,同时,证明了所给的Fiducial分布具有频率性质.然后,研究在参数受到单侧限制时,Fiducial分布与后验分布等同的问题,给出的充要条件是分布族为指数分布族,此时,先验分布是一个广义先验分布,它不能被Lebesgue测度控制.最后,证明了在参数限制在一个有限区间内时,Fiducial分布与任何先验(包括广义先验分布)下的后验分布不等同. 相似文献