排序方式: 共有51条查询结果,搜索用时 15 毫秒
1.
Tao Liu Yong-Gang Wei Qi-Hua Wu Qing-Xiang Guo 《Research on Chemical Intermediates》2005,31(9):833-844
A series of adamantanamine-(OCH2CH2)n-phenothiazine (n = 0, 1, 2, 3) electron donors was synthesized. Photoinduced electron transfer was observed in the supramolecular complex
of the phenothiazine derivatives with p-nitrobenzoyl-β-cyclodextrin (NBCD) through binding of the adamantyl group by the NBCD cavity, which is stabilized clearly via hydrophobic interactions in aqueous solution. Detailed Stern–Volmer constants were measured and they were partitioned into
dynamic Stern–Volmer quenching constants and static binding constants. The results revealed an efficient electron transfer
process inside the supramolecular systems compared to that controlled by diffusion. This observation also indicates that the
chain length will influence the electron transfer efficiency of a supramolecular donor–acceptor system. 相似文献
2.
Yong Wang Zheng-bao He Zuo-wan Zhou 《高分子科学》2007,(6):565-572
The objectives of this paper are to understand the crystallization behavior of polypropylene(PP)composites with surface modified tetra-needle-shaped zinc oxide whisker(T-ZnOw).T-ZnOw was surface modified with different coupling agents,such as silane coupling agents(KH-550,KH-560)and titanate coupling agent(NDZ-105),in order to improve the compatibility between PP and T-ZnOw.DSC and POM were used to characterize the melt and crystallization behavior and the crystalline structures of the composites,respectively.The results show that the surface modified T-ZnOw acts as a nucleating agent of PP crystallization,depending on the coupling agent used for modification.KH-550 and KH-560 have more apparent role in improving the interfacial interaction than NDZ-105 and induce PP crystallization at higher temperature and with smaller spherulites size.The results also suggest that the crystallization behavior depends on not only the content of coupling agent,but also the content of the surface modified T-ZnOw used in the composites. 相似文献
3.
本文首次报道了将敏化和猝灭同时偶合在同一体系中的敏化/猝灭室温磷光新方法。体系中, CTAB胶束一方面增强α-溴代萘的室温磷光发射、α-溴代萘和联乙酰的三重态-三重态能量转移效率, 另一方面起到猝灭α-溴代萘敏化联乙酰发射的室温磷光的作用。CTAB对联乙酰的猝灭反应由三重态-三重态能量转移速率限制,求得α-溴代萘敏化联乙酰的三重态-三重态能量转移速率常数为1.76×10^9(mol.dm^-^3)^-^1s^-^1, CTAB对联乙酰的猝灭常数为7.82×10^7(mol.dm^-^3)^-^1s^-^1。详细研究了实验条件, 实现了猝灭法测定联乙酰,检测限达2.8×10^-^8mol.dm^-^3。 相似文献
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5.
The possibility of performing in proximity of the Earth experiments to test the predictions of general relativity for the trajectories of particles and photons in weak gravitational fields is studied. Three experiments are analyzed, all based on optical detection methods. The first experiment would allow to detect the tidal acceleration using a freely-falling Michelson interferometer. In a second experiment, based on laser-ranging methods, the relativistic correction to the classical gravity acceleration could be detected. Finally, the possibility of detecting light deflection induced by space curvature in an optical cavity with high-reflectivity mirrors is discussed. 相似文献
6.
本文以邻菲罗啉和二茂铁为原料,合成了一系列新Schiff碱型二茂铁衍生物:(C~10H~6N~2)C=N-N=CR-Fc,(C~10H~6N~2)C=N-C~6-H~4-N=CR-Fc,(C~10H~6N~2)C==N-C~6H~4-N=CR-Fe,(R=H,CH~3,Fc为二茂铁基;并对其进行了元素分析和光谱表征,该类二茂铁衍生物能有效地猝灭Ru(bpy) 的发光,Stern-Volmer图呈线性关系,双分子猝灭过程速率常数K~q为10°dm^3/mol.s^-3数量级.猝灭过程按电子转移还原机理进行. 相似文献
7.
合成了含二氮芴和联吡啶等配体的一系列新型钌铁双核配合物:[(C~1~0H~6N~2)C=N-N=CR-Fc)Ru(bpy)~2]·(PF~6)~2,[(C~1~0H~6N~2)C=N--C~6H~4-N=CR-Fc)Ru(bpy)~2]·(PF~6)~2,[(C~1~0H~6N~2)C=N-C~6H~4-C~6H~4-N=CR-Fc)Ru(bpy)~2]·(PF~6)~2,并对其进行了光谱表征,通过对该类配合物的循环伏安和发光光谱研究,讨论其激发态的氧化还原性和对[Ru(bpy)~3]^2^+发光过程的猝灭作用.研究表明猝灭过程为扩散控制的双分子交换能量传递 相似文献
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9.
S.S. Madaeni A. Rahimpour 《高分子科学》2005,(5):539-548
Polyethersulfone membranes were prepared from quaternary systems containing N,N-dimethylacetamide (DMAc) as solvent, polyvinylpyrrolidone (PVP) as constant additive and acetic acid, acetone and water as variable additives. Phase inversion via immersion precipitation was employed for manufacturing of membranes. The prepared films were immersed in the mixture of pure water and 2-propanol (30/70 vol%) as the non-solvent. Acetic acid caused an increment in the flux at high polymer concentration (16 wt%) and a decline in the flux at low polymer concentrations (10 wt% and 13 wt%). Acetone and water as the solvent in the casting solution declined the flux at any polymer concentration tested. The morphology and performance of the prepared membranes were investigated by scanning electron microscopy and separation experiments using milk as the feed. 相似文献
10.
Qian Chen Bo-Lin Lin Yao Fu Lei Liu Qing-Xiang Guo 《Research on Chemical Intermediates》2005,31(9):759-767
Ligand effects on ethene insertion into a series of cationic phenylpalladium complexes with diverse bidentate phosphine ligands
were studied by using the density functional methods. For the complexes with n-membered ring ligands (n = 4–6), a correlation was found between the ring size and the insertion barrier. This behavior was explained by considering
the P—Pd—P bond angle. In the case of complexes with ligands of different rigidity, almost no difference was found for the
insertion barriers. Furthermore, the bidentate phosphine ligand was systematically substituted by Me, t-Bu, F and Ph groups.
It was found that the electron-donating substituents increased the insertion barrier, whereas the electron-withdrawing groups
decreased it. The substantial increase of insertion barrier by the t-Bu group indicated that steric effect also had great
effect on the migratory insertion. 相似文献