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991.
聚合物强化辐射交联研究进展 总被引:1,自引:0,他引:1
本文综述卫应用含有多个C=C不饱和基团的多官能团单体来强化辐射交联聚合物的研究进展,对强化交联的反应机理、多官能团单体的强化交联行为、强化交联的影响因素及强化交联的研究表征方法进行了介绍。 相似文献
992.
Chen Xia DU Zhi Qiang WANG Qi XIN Yang Jie WU Wen Lian LI Department of Chemistry Zhengzhou University Zhengzhou Changchun institute of optics Fine Mechanics Physics Chinese Academy of Sciences Changchun 《中国化学快报》2005,(5)
In recent years, the interest in developing luminescent lanthanide complexes has been greatly stimulated by their potential use in electroluminescent displays1. Europium complexes appear most attractive in view of the high photoluminescent efficiency and the high monochromatic red light that are widely exploited in full-color displays2. It has been approved that the second ligand plays an important role in europium complexes, the synergistic complexation of the second ligand can not only lead … 相似文献
993.
Lingjia Xu Liangliang Zhu Shi Wu Xiaopeng Chen Qiwen Teng 《Central European Journal of Chemistry》2006,4(4):732-742
Supermolecular complexes formed by oligophenyleneethynylene derivatives and isophthalic acid were studied using AM1 method
to obtain binding energy. Electronic spectra and IR spectra of the complexes were calculated by INDO/CIS and AM1 methods based
on AM1 geometries. Results indicated that the dimer could be formed by the monomers via hydrogen bonding because of the negative
binding energy. Binding energy of the complexes was affected by electronegativity and steric effects of the substituents.
The first UV absorptions and IR frequencies of N-H bonds of the complexes were both red-shifted compared with those of the
monomers. The complexes could bind small molecules via hydrogen bonds, resulting in the change in UV absorptions and an increase
in IR frequencies of N-H bonds. 相似文献
994.
Yong Li Xiao-Bing Cui Ji-Qing Xu Ke-Chang Li Guang-Hua Li Qing-Xin Yang 《Journal of solid state chemistry》2005,178(1):363-369
Both the homometal cluster [P(ph4)]2[Mo2O2(μ-S)2(S2)2] (1) and [Mo2O2(μ-S)2(Et2dtc)2] (2) (Et2dtc=diethyl-dithiocarbamate) were successfully synthesized by low-temperature solid-state reactions. X-ray single-crystal diffraction studies suggest that compound (1) is a dinuclear anion cluster, and compound (2) is a dinuclear neutral cluster. The two compounds were characterized by elemental analyses, IR spectra and UV-Vis spectra. The third-order non-linear optical (NLO) properties of the clusters were also investigated and all exhibited nice non-linear absorption and self-defocusing performance with moduli of the hyperpolarizabilities 5.145×10−30 esu for (1) and 5.428×10−30 esu for (2). 相似文献
995.
Gryczynski I Gryczynski Z Lakowicz JR Yang D Burke TG 《Photochemistry and photobiology》1999,69(4):421-428
Topotecan is an antitumor agent with activity against a variety of cancers. We examined the steady-state and time-resolved fluorescence spectral properties of topotecan with one- and two-photon excitation. Topotecan was found to display a high two-photon cross section near 20 GM for wavelengths within the fundamental output of a Ti:sapphire laser, 800-880 nm. In frozen solution the anisotropies of topotecan are near the theoretical maxima for one-photon and two-photon excitation with colinear electronic transitions. The intensity and anisotropy decays of topotecan fluorescence were found to be homogeneous (single exponentials) in phosphate-buffered saline and propylene glycol. The steady-state and time-resolved data indicate that topotecan binds to a double-helical DNA oligomer d(AT)10 resulting in increased anisotropies and multiexponential intensity and anisotropy decays. Subnanosecond components in the anisotropy decay of the DNA-topotecan complex suggest loose binding of the drug to DNA. Loose binding of topotecan to DNA is also revealed by accessibility of topotecan to collisional quenching by iodide. 相似文献
996.
聚乙烯醇双胺肟螯合纤维的合成及其吸附性能 总被引:5,自引:0,他引:5
利用预辐接技法合成了聚乙烯醇双胺肟螯合纤维。研究了影响接枝率和胺肟基团含量的因素,讨论了吸附酸度、吸附时间对Cu(Ⅱ)离子吸附容量的影响。 相似文献
997.
气相色谱质谱联用仪与微机的数据传输和处理 总被引:1,自引:0,他引:1
报道了一种用于气相色谱质谱联用仪和微机之间实现数据传输和处理的方法。方法可更有效地利用质谱仪采集的数据,解决了工作站处理数据的局限性。经数据格式转换,原始数据可以在微机上实现色谱峰再现,从而为色谱条件的优化和定量数据处理创造了条件。 相似文献
998.
有机磷配位铐或钴联基配合物是生产难或醇的工业催化剂,一般公认金属氢化物是反应的催化活性物种.通常反应活性物种仅存在干反应状态下,其结构表征非常困难,在许多研究中只能关联催化剂母体与其活性的关系[‘1;而未能揭示出催化的本质,给催化剂设计造成很大困难,因而对催化剂活性物种的直接表征受到普遍关注.B。wn问、Morrista]及本文作者研究组*均采用加压原位红外光谱方法,在烯烃氢甲酸化反应条件下捕捉到HCO(CO)3L存在的信息·但用相同方法在反应条件下,在RhH键特征吸收谱带195O-2200Cm‘内未观测到错氢化物的Rh-… 相似文献
999.
Xi‐Zhao Wang Jiong Jia Yan Zhang Wei‐Ren Xu Wei Liu Fang‐Niu Shi Jian‐Wu Wang 《中国化学会会志》2007,54(3):643-652
The synthesis of a series of new 5‐isoxazolpenicillins is described, which were obtained by coupling substituted isoxazoles with 6‐APA. Concise large‐scale synthesis of 3,5‐disubstituted isoxazoles by 1,3‐dipolar cycloaddition using copper(I) as catalyst was also investigated. Representative compounds were assayed for antimicrobial activities, showing satisfactory antimicrobial activities against Gram‐negative bacteria. 相似文献
1000.
Yan?Zhang Changchun?Wang Wuli?Yang Bin?Shi Shoukuan?FuEmail author 《Colloid and polymer science》2005,283(11):1246-1252
Biodegradable tri-component diblock copolymer was synthesized by bulk copolymerization of ε-caprolactone (CL) and D, L-lactide (LA) in the presence of methoxy poly(ethylene glycol) (MePEG), using stannous octoate as catalyst. Their chemical
structure and physical properties were investigated by GPC, NMR, DSC, TGAand XRD. The increase of CL/LA ratio in the diblock
copolymer leads to lower T
g, higher decomposition temperature and crystallinity. Nanoparticles formulated from MePEG–poly(CL-co-LA) (PCAE) possess spherical structure, which was characterized by dynamic light scattering (DLS) and transmission electron
microscopy (TEM). The DLS results indicate that the particle size increased with the increase of CL/LA ratio and the hydrophobic
fragment length in the copolymer. The drug encapsulation efficiency and the drug release behavior in vitro conditions of camptothecin
were measured by high performance liquid chromatography (HPLC). The encapsulation efficiency can be achieved as high as 84.4%
and the release behavior can be made well-controlled. MePEG–poly(CL-co-LA) nanoparticles might have a great potential as carriers for hydrophobic drugs. 相似文献