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91.
A free standing film of polyaniline as large as 18 cm×18cm×0.002 cm can be obtained by evaporation of a solution of the chemically synthesized base in NMP. Its structure was examined by the elemental analysis, IR, U.V.-visible spectra, XPS, DSC, SEM and X-ray scattering and its conducting behavior as well as electrochemical properties were studied. Results show that the composition, structure of main chain, physical properties of the free standing film of polyanilme is similar to that of the powder. However, some differences in its electronic structure, conductivity at room temperature and potential of redox couple between the flee standing film and powder are observed, which may be due to cross-linking of the film of polyaniline. 相似文献
92.
An investigation of electronic structure in some neurotransmitter drugs has been made using the CNDO/2 semi-empirical molecular orbital method.The electronic structure has been conveniently characterized by the electronic parameters nett atomic population (NAP) and bond index (BI). A variation of these electronic parameters with respect to conformation has been studied and has been found unlikely to exceed 0.1 e in most. cases. Further, the useful extent to which the electronic parameters of some commonly occurring functional groups may be regarded as conformationally invariant has been demonstrated. Also presented are (i) a discussion on the intramolecular close-approach of functional groups — the interaction between terminal —COO? and ?NH3+ groups of α-ω anaino acids is explicitly considered; (ii) an enquiry into the extension of ‘standard’ (idealized) geometry models in the elucidation of electronic structure.The implication of the results and observations presented here are briefly discussed with reference to classical and quantum structure-activity studies of drug molecules. 相似文献
93.
94.
Selective laser-induced phototautomerism of free-base porphin in different n-alkanes (n-hexane, n-heptane, n-octane, nnonane, n-decane, n-undecane and n-dodecane) has been used to identify tautomer splittings in a number of sites in polycrystalline samples at 2 K. Pairs or lines arising from the two molecular orientations in each site can be reversibly transformed into each other. In the odd n-alkanes the occupation of different sites was not dependent on the rate at which the samples were frozen, but in the even n-alkanes metastable sites were only occupied following rapid quenching. 相似文献
95.
程序涂渍柱“柱效能程序效应”的研究 总被引:1,自引:0,他引:1
本文从理论上给出程序柱“柱效能程序效应”的概念并导出了函数关系式,通过计算机可计算柱效能程序效应与柱内各变量之间的关系,实践证明实验数据的变化趋势与理论数据相符。 相似文献
96.
讨论了沸点升高法测定混和溶剂化热和汽化熵的原理,并用拟静态法测定了乙醇-丙酮,并-四氯化碳和苯,甲苯三组混和溶剂在不同组成下的正常沸点,根据沸点数据求得了混和泶微分汽化热和汽化熵,实验结果表明,二元混和溶剂与理想溶液偏离不大时,其正常汽化熵符合Trouton规则。 相似文献
97.
溶胶凝胶分配理论是在分子水平上表征交联网络结构的有效工具。由Flory等建立和发展起来的这一理论,由于引用了溶胶相无分子内环化反应的假定,特别是在理论推导中将分子内交联反应与分子间的链增长反应对两相分配的贡献未能加以区别,致使理论与实验不符。本文充分考虑了经典理论的这些缺欠,建立了更为符合客观实际的理论模型。同时,用十分简便的方法推导了反应溶胶分数,溶胶反应程度,分子内和分子间总反应程度等量宏观联系的参数方程组。以聚酯为模型化合物的实验研究与本文所得理论结果基本相符。 相似文献
98.
99.
用MNDO方法,全构型优化,研究了15个氮自由基4-RC6H4NH,和15个氧自由基4-RC6H4O(R=-H;-OCH3,-Cl,-F,-CN,-COCH3,-NO2,-CH3,-CF3,-SCH3,-C6H5,-Nh2,-BH2,-PH2,-SiH3)的稳定化能.结果表明:-NH2,-CH3,-OCH3,-F基团对自由基起稳定化作用,-CF3,-NO2;-CN,-COCH3,-BH2基团对自由基起去稳定化作用.苯基对氧自由基有较大的稳定化作用,而对氮自由基的稳定性影响较小.-SCH3,-PH2,-SiH3,-Cl基团表现弱的去稳定化作用.计算和实验结果基本相符. 相似文献
100.
The ionization threshold of fluoranthene and of TMPD in n-pentane was determined by laser two-photon ionization (TPI) and found to be 4.50 ± 0.05 and 3.88 ± 0.05 eV respectively. For both molecules the TPI spectra show distinct structure due to autoionization. For fluoranthene the TPI spectrum suggests that the molecule dissociates via the first excited singlet state. 相似文献