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排序方式: 共有445条查询结果,搜索用时 15 毫秒
31.
用毛细管流动色谱法分析丙烯在HZSM-5上聚合反应尾气,将此法与气相色谱-质谱联用技术相结合,对各反应产物分别定性,此法即可一次完成丙烯聚合反应产物的完全分离和定量。随着反应温度升高,尾气中芳构化产物增加,C_(4-6)链烃含量下降;丙烯通过齐聚物环化脱氢进行芳构化。 相似文献
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YuYingFENG XiaoTianGU JiaHongZHOU JianChunBAO GangLI TianHongLU 《中国化学快报》2004,15(12):1505-1508
New Ge/SiO2 glasses have been synthesized by heating the GeO2/SiO2 dry gels under H2 gas at 700℃. The resulting fluorescence spectra show that this kind of Ge/SiO2 glasses emit strong photoluminescence at 392 nm (3.12 eV), medium strong photoluminescence at 600 nm (2.05 eV) and weak photoluminescence at 770 nm (1.60 eV) respectively. Possible photoluminescence mechanisms are also discussed based on the results of X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS). 相似文献
35.
QSAR Studies on the COX-2 Inhibition by 3,4-Diarylcycloxazolones Based on MEDV Descriptor 总被引:2,自引:0,他引:2
Selective inhibition of cyclooxygenase-2 (COX-2) might avoid the side effects of current available nonsteroidal antiinflammatory drugs while retaining their therapeutic efficacy. A novel variable selection and modeling method based on prediction is developed to construct the quantitative structure-activity relationships (QSAR) between the molecular electronegativity distance vector (MEDV) based on 13 atomic types and the biological activities of a set of selective cyclooxygenase-2 inhibitory molecules, 3,4-diarylcycloxazolones (DAA) plus indomethacin,naproxen, and celecoxib. Using multiple linear regression, a 5-variable linear model is developed with the calibrated correlation coefficient of 0.9271 and root mean square error of 0.17 in modeling stage and the validated correlation coefficient of 0.9030 and root mean square error of 0.20 in leave-one-out validation step, respectively. To further test the predictive ability of the model, 20 DAA compounds are picked up to construct a training set which is used to build a QSAR model and then the model is employed to predict the biological activities of the balance compounds. The predicted correlation coefficient and root mean square error are 0.9332 and 0.19, respectively. 相似文献
36.
Nian Yun YANG Shi Hui QIAN Jin Ao DUAN Ping LI Li Juan TIAN Jiangsu Academy of Traditional Chinese Medicine Nanjing China Pharmaceutical University Nanjing Jinling Pharmaceutical Company Limited Nanjing 《中国化学快报》2005,16(9)
Various germacrane sesquiterpenes have been isolated from many species of the Eupatorium.In recent years these compounds have been increasing interest due to their insecticidal,cytotoxic,antitumor-promoting and insect-antifeedant activities1.In our present study,we have investigated the chemical constituents of Eupatorium lindleyanum DC.,which is a geo-authentic medicine of Jiangsu province.It is used as a antipyretic drug.Two novel germacrane sesquiterpenes(Figure1)were found by us from th… 相似文献
37.
TIAN Yan-Ni YANG PinInstitute of Coordination Chemistry The State Key Laboratory of Coordination Chemistry Nanjing University Nanjing Jiangsu ChinaLI Qing-Shan ZHAO Chun-GuiInstitute of Molecular Science Shanxi University Taiyuan Shanxi China 《中国化学》1996,14(5):428-436
New complexes,of bis(2,2'-diamino-4,4'-bithiazole)sulfate nickel(Ⅱ) and bis(2,2'-diami-no-4,4'-bithiazole)sulfate cobalt(Ⅱ),have been prepared.The complexes were characterized by infrared and UV-Vis spectroscopy,1H NMR,elemental analyses and molar conductivity.The effect of these complexes on the DNA synthesis of sarcoma 180 cells has been studied by the technique of isotopic liquid scintillation.The results indicated that complexes show ability to inhibit DNA synthesis of the tumor cells.In order to provide a molecular basis for understanding the biological effects,the probe,[trana-en2Os(η2-H2)](CF3SO3)2 (en,ethylenediamine) as a monitor was first used to explore interaction of the complexes with 2'-deoxyguanosine-5'-monophosphate (dGMP). 相似文献
38.
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
39.
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
40.
JIANG Hua ZHANG Quanxing CHEN Jinlong Nanjing Electric Power Automation Equipment General Factory The State Power Cooperation of China Nanjing China The State Key Laboratory of Pollution Control & Resources Reuse Dept. of Environme 《Chinese Journal of Reactive Polymers》2002,(1)
1. INTRODUCTION 1,2,4-acid (1-Amino-2-naphthol-4-sulfonic acid) is among the most important naphthalene derivatives which are widely used as the intermediates of dyestuffs. In its production process, however, high strength wastewater streams are gene… 相似文献