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961.
π‐Conjugated poly(3‐nitropyridine‐2,5‐diyl) ( PPy‐3‐NO2 ), poly(3,3′‐dinitro‐2,2′‐bipyridine‐5,5′‐diyl) ( PBpy‐3,3′‐diNO2 ), and a poly(arylene ethynylene) type polymer consisting of a 3,3′‐dinitro‐2,2′‐bipyridine unit ( PAE‐1 ) were synthesized by Cu‐promoted Ullmann coupling reaction and Pd‐catalyzed coupling reaction. PPy‐3‐NO2 and PAE‐1 were soluble in organic solvents such as DMSO, DMF, and chloroform, and gel permeation chromatography analysis showed a number average molecular weight (Mn) of 9,300 and 12,300, respectively. PPy‐3‐NO2 gave intrinsic viscosity, [η], of 0.53 dL g?1 in DMF. PBpy‐3,3′‐diNO2 had somewhat lower solubility. The polymers exhibited a UV–vis peak at about 430 nm. PPy‐NO2 received electrochemical reduction at ?1.5 V versus Ag+/Ag in acetonitrile, and gave an electrochemical redox cycle in a range from 0 to ?1.1 V versus Ag+/Ag in an aqueous solution. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1763–1767, 2006 相似文献
962.
本文对列管式废热锅炉火管管间液体流速场和温度场进行了实验研究.采用W1269型水热膜探头和1050型热膜风速仪测定了流场速度分布,用铠装热电偶测量了工质温度分布,并就出水口位置的影响进行了研究,根据实验结果对流场进行了分析,解释了实际应用中上管板经常变形和泄漏等事故的起因. 相似文献
963.
由于其特殊的光学和电子性质,共轭聚合物受到人们的广泛关注.共轭聚合物可以在各种传感器件中用作活性材料,例如:生物传感器;气体、湿度传感器;离子传感器;压力、温度传感器等.本文综述了共轭聚合物在传感器应用方面的一些新的进展. 相似文献
964.
S. Saravanan C. Joseph Mathai M. R. Anantharaman S. Venkatachalam P. V. Prabhakaran 《应用聚合物科学杂志》2004,91(4):2529-2535
Electrically conductive organic and metalloorganic polymers are of great interest and they have applications in electronic, optical, photonic, photoelectric, electrochemical, and dielectric devices. Tetrameric cobalt phthalocyanine was prepared by conventional chemical method. The dielectric permittivity of the tetrameric cobalt phthalocyanine sample was evaluated from the observed capacitance values in the frequency range 100 KHz to 5 MHz and in the temperature range of 300 to 383°K. It is found that the system obeys the Maxwell Wagner relaxation of space charge phenomenon. Further, from the permittivity studies AC conductivity was evaluated. The values of AC conductivity and DC conductivity were compared. Activation energy was calculated. To understand the conduction mechanism Mott's variable range hopping model was applied to the system. The T?1/4 behavior of the DC conductivity along with the values of Mott's Temperature (T0), density of states at the Fermi energy N (EF), and range of hopping R and hopping energy W indicate that the transport of charge carriers are by three‐dimensional variable range hopping. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2529–2535, 2004 相似文献
965.
照相染料还原电位的研究 总被引:1,自引:0,他引:1
本文测定了八个照相染料在不同pH条件下的还原电位。发现其中一些增感染料的还原电位与其溶液的pH值无关,而一些减感染料依赖于pH值的变化。本文用染料质子化机理分析了这些结果。 相似文献
966.
967.
Molecular dynamics simulations of merging process of two isolated cyclic chains and that of linear chains have been performed, in order to find the difference between the two kinds of chain in bulk and in vacuum, where surface of the system restrains thousands of configurations showing up. Analysis indicates that in such confinement the chain ends at most moments float on the surface layer, and their mobility is much larger than the mean value of all atoms in linear chains, or that in cyclic chains. Comparison of the merging processes of cyclic chains and their linear counterparts was intensively carried out by several means of analyzing the trajectory files in statics and in dynamics. It was found that the segments of cyclic chains showed almost the same behavior of motion with that of linear chains. This is different diffusion behavior from that in bulk systems, where the cyclic chain has much higher diffusion rate. This modeling therefore indicates that in these confined systems because of the surface energy, the end groups are involuntarily kept on the surface, and lost the capacity of leading chain reptation through the other polymer chains, which is possibly the origin that the difference of diffusion behavior between the linear chain and the cyclic chain in the bulk almost disappears in the case of the confinement. 相似文献
968.
赵雯 《安徽水利水电职业技术学院学报》2009,9(4):28-30
分析了加筋土的结构特点及计算方法,结合临淮岗船闸工程监测数据,分析了加筋土对于高边墙水平荷载的减载效果。 相似文献
969.
崔静 《四川轻化工学院学报》2011,(5):596-598
利用马氏链的一般理论讨论了随机环境中马氏链的性质和状态分类。借助于随机环境中马氏链的特征数,首先讨论了状态本质与正则本质的关系,给出了正则本质态的一个充分条件,在此基础上研究了弱常返态与正则本质态的关系及本质态与非正则本质态的关系,而后在状态空间有限及联合空间不可分解的条件下对状态空间进行了分解。最后举出一个实例说明了文章结论的正确性。 相似文献
970.