208 resultados para 13-132
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采用柠檬酸爆炸法合成了系列层状钙钛矿型复合氧化物La4BaCu5 - xMxO13+ λ(M= Mn,Co; x= 0 ~5) 催化剂. 用TPD,TPR 和化学分析法对催化剂进行了表征,考察了催化剂在CO还原NO 中的催化活性.结果表明,掺杂Mn,Co 后催化剂中的活性氧含量及氧化还原性质发生了变化. 掺杂少量Mn,Co 可使催化剂在CO 还原NO中的催化活性明显提高,且掺杂Co 的样品比掺杂Mn 的样品活性提高更明显.这是由于CuMn 与CuCo 之间的协同作用不同导致的结果.
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运用多元回归分析和人工神经网法对18个吡啶和喹啉类化合物的118个化学位移进行计算机模拟,并应用碳原子的空间和电子结构特征来表征其所处的化学环境,从而获得了比较好的相关模型。波谱模拟技术对辅助有机化合物结构解析和化学位移的确认是十分有用的工具。
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用多元回归方法对 59个直链或支链烷烃化合物进行碳 - 1 3NMR波谱模拟。在这个实验中提取了分子连接性指数和几何参数 ,取得了很好的效果。
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通过计算机辅助方法对1 3 CNMR化学位移进行预测 .这个方法包括分子拓扑指数和几何参数特征值的计算及对所选特征进行的变量压缩 ,并对所选共振碳的化学位移与其提取的特征进行多元回归分析 ,从而得出其相关数学模型 .本文预测了环己烷中 45个仲碳原子的1 3 C化学位移 ,其标准误差约为 1 .4ppm.
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为饱和醛酮类化合物的1 3C核磁共振波谱模拟 .根据该类化合物的特点 ,提取了分子的拓扑特征 ,几何特征及电子特征 .应用变量最优子集回归法进行了变量的选择 ,并用这些变量构造了回归模型 .交叉验证的结果表明 ,所得数学模型比较稳定 ,并得到了较好的预测结果
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Prediction of C-13-nuclear magnetic resonance chemical shifts for aliphatic amines is performed. The topological, geological and electronic descriptors are generated. To reduce the variables, the best subsets of the descriptors are obtained by using leaps-and-bounds regression analysis. The model is achieved using multiple regression with satisfactory results.
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The characterization of free base porphyrin 2,3,7,8,12,13,17,18-octakis(hexyl-thio) tetraazaporphyrin (H(2)OHTTAP) and its zinc(II) complexes [Zn(II)OHTTAP] containing eight thioether groups at the beta -pyrrole positions of the macrocycle was reported. Results obtained by cyclic voltammetry and differential pulse voltammetry indicated a five-electron reduction in five steps for each complex. They were oxidized in two single-electron-transfer steps to yield pi -cation radicals and dications and reduced in three single-electron-transfer steps to yield pi -anion radicals, dianions and trianions, respectively. The redox property of H(2)OHTTAP was unusual as compared to porphyrins (PPs) and phthalocyanines (Pcs). Each process was monitored by in situ thin-layer spectroelectrochemistry, which indicated that only the Ligand was electroactive. The existence of the eight hexylthio groups was responsible for the intrastack interactions and enhanced intracolumnar and intercolumnar electron motions, resulting in improved conductivity. Copyright (C) 2001 John Wiley & Sons, Ltd.
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对脂肪胺类化合物的1 3C核磁共振波谱进行了模拟 ,所用方法为数学模型法。为此 ,提取了共振碳原子所处化学环境的拓扑特征、几何特征及电子特征。运用变量最优子集回归法对变量进行了选择 ,用多元回归法构造了数学模型 ,得到了比较满意的预测结果。
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为了C-13NMR的自动解析,ESESOC系统从13CNMR本身的特征出发, 提出了不确定层数的子结构模型。即以共振碳原子为中心,以与之相连的完整的官能团为外围环境, 对这样的子结构, 其外围环境根据官能团的不同可以是一层、或二层乃至多层, 即环境层数是可变的。在此子结构模型的基础上, 从CIAC-13CNMR谱图数据库统计出13CNMR知识库。
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The complexes of a series of rare earths with Ge-132 have been prepared. The carboxyl anions of Ge-132 molecule were coordinated to rare earth ion with chelate style. In the complexes molecule, the GeO3/2 group of Ge-132 were hydrolyzed to become -Ge(OH)(3) group, and later does:not coordinate with rare earth ions. All of the complexes possess similar properties. In aqueous solution of pH 6 and 50 degrees C, these complexes can obviously selectively catalytically hydrolize the phosphatide bond of 5'-AMP and 5'-dAMP into phosphatic acid and riboside.
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The fluorescences of BSA and glycosylated BSA were observed respectively. The lambda(cm) of BSA was 340 nm; while the lambda(cm) of glycosylated BSA was 436 nm. Because the fluorescence spectra of them were different greatly, we can observe the suppression of Ge-132 on the Maillard reaction of BSA without any interference of itself. It was showed that the fluorescence intensity of glycosylated BSA increased continuously with the cultured time, Ge-132 may suppress the Maillard reaction of BSA greatly, and the suppressing efficicency would be 32 %. The key site of the Maillard reaction of BSA is free amino groups of alanine residues on N-terminal amino group, besides the epsilon-amino groups of intrachain Lysine residues.
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用人工神经网和多元回归方法对含2个碳的21个卤代化合物的35个化学位移进行计算机图谱模拟,结果表明,人工神经网络方法优于多元回归方法,同时此种方法处理这类问题有明显的优势。波谱模拟技术在有机化合物结构解析中是非常有用的方法。
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Ge-132是具有广泛生物活性的一元羧酸有机锗倍半氧化物的低聚物,分子中存在类似冠醚的Ge-O-Ge大环结构.因此,有人认为Ge-132的生物活性可能与这种大环结构与体内金属离子形成配合物有关[1],但尚无直接的实验证据.因此,合成Ge-132稀土配…
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人体内氨基酸及蛋白质的非酶糖化反应(Mailard反应)与糖尿病及其并发症的关系已经引起广泛注意[1].有机锗化合物β-羧乙基锗倍半氧化物(Ge-132)具有预防糖尿病及调节糖代谢的作用[2].研究Ge-132对Mailard反应的抑制作用,对于开发…
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合成了一系列结构为层状ABO3的复合氧化物La4BaCu5-xMxO13(M=Mn,Co),并利用XRD、X射线能谱、氧程序升温脱附和化学分析方法对它们的结构和活性氧种进行了研究。XRD分析结果表明:它们的结构为五层的ABO3结构。活性氧种的研究表明La4BaCu5O13中掺杂Mn或Co之后,样品中明显存在的MCu(M=Mn,Co)之间的协同作用,并且CuMn之间协同作用明显比CuCo的强。