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161.
Shiming Zhang Yugeng Wen Weiyi Zhou Yunlong Guo Lanchao Ma Xingang Zhao Zhen Zhao Stephen Barlow Seth R. Marder Yunqi Liu Xiaowei Zhan 《Journal of polymer science. Part A, Polymer chemistry》2013,51(7):1550-1558
Solution‐processable polymers consisting of perylene diimide (PDI) acceptor moieties alternating with dithienothiophene (DTT), N‐dodecyl‐dithienopyrrole (DTP), or oligomers of these donor groups have been synthesized. We have, in addition to varying the donor, varied the N,N′ substituents of the PDIs. The thermal, optical, electrochemical, and charge‐transport properties of the polymers have been investigated. The polymers show broad absorption extending from 300 to 1000 nm with optical band gaps as low as 1.2 eV; the band gap decreases with increasing the conjugation length of donor block, or by replacement of DTT by DTP. The electron affinities of the polymers, estimated from electrochemical data, range from ?3.87 to ?4.01 eV and are slightly affected by the specific choice of donor moiety, while the estimated ionization potentials (?5.31 to ?5.92 eV) are more sensitive to the choice of donor. Bottom‐gate top‐contact organic field‐effect transistors based on the polymers generally exhibit n‐channel behavior with electron mobilities as high as 1.7 × 10–2 cm2/V/s and on/off ratios as high as 106; one PDI‐DTP polymer is an ambipolar transport material with electron mobility of 4 × 10–4 cm2/V/s and hole mobility of 4 × 10–5 cm2/V/s in air. There is considerable variation in the charge transport properties of the polymers with the chemical structures. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
162.
Shi Wang Xue-Hua Ding Jing-Lin Zuo Xiao-Zeng You Wei Huang 《Coordination chemistry reviews》2011,255(15-16):1713-1732
Cyano-bridged molecule-based magnetic materials with reduced dimensionality, such as single-molecule magnets (SMMs) and single-chain magnets (SCMs), have attracted great research interest during the last decade. Among the cyano-based molecular precursors with ample coordinating capability, we note the ability of the tricyanometalate to link various metal ions lead to a wide diversity of structural architectures ranging from discrete polynuclear complexes to various one-dimensional (1D) assemblies. Some of them are promising cyano-bridged SMMs and SCMs. The use of capping tridentate organic ligands results in a number of clusters containing di-, tri-, tetra-, penta-, hexa-, octa-, fourteen-nuclear and various 1D metal-cyanide molecular architectures. Here we review the structural topologies of these complexes and their related magnetic properties, highlight typical examples, and point out the main possible directions that remain to be developed in this field. From the crystal engineering point of view, the compounds reviewed here should provide useful information for further design and investigation on this elusive class of cyano-bridged SMMs and SCMs. 相似文献
163.
Submicron-sized Bi2Fe4O9 crystals were successfully synthesized via the hydrothermal method, while micron-sized Bi2Fe4O9 crystals with rod-like morphologies were obtained in the presence of the mineralizer KNO3. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were employed to characterize the products. According to a series of time-dependent experiments, it was concluded that the likeliest formation mechanism for the microrods was the Ostwald ripening process. It was proposed that the blocking effect of NO3? contributed to the formation of the rod-like powders. Moreover, the optical absorption of the prepared Bi2Fe4O9 crystals was measured using an UV–vis spectrophotometer, indicating that Bi2Fe4O9 powders can be used as effective photocatalysts under visible light. 相似文献
164.
Sensitivity analysis of linear vibration system is of wide interest. In this paper, sensitivity analysis based on non-defective system and defective system is summarized in all cases. Specially, for the defective systems, a fast method for the perturbation problem of state vectors is constructed in terms of the theories of generalized eigenvectors and adjoint matrices. By this method, the state vector derivatives can be expressed by a linear combination of generalized eigenvectors. The expansion coefficients can be obtained without solving large-scale equations based on eigensolutions of original system. Numerical results demonstrate the effectiveness and the stability of the method. 相似文献
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Zheng Wu WANG Gan Zuo LI* Da Ren GUAN Xi Zhang YI An Jing LOU Key Lab of Colloid Interface Chemistry for State Education Ministry Shandong University Ji''''nan Institute of Theoretical Chemistry Shandong University Ji''''n 《中国化学快报》2001,(7)
The electrical double layer theory is the base of the colloid stability theory (DLVO theory), and the PB eq. is a key to the study of the layer1,2. For a spherical particle, the PB eq. is (1) where and are the dielectric constant of the medium, the valence of ions, the elementary charge, the concentration of ions far away from the particle, the Boltzmann's constant and the temperature of the system, respectively. Since this eq. is a second order nonlinear differential one, only the anal… 相似文献
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用红外光谱法测试研究了餐盒用新型非发泡聚丙烯光降解行为。结果表明,降解母粒含量不同,其红外吸收光谱图存在明显的差异;在光降解过程中,羰基指数存在明显的动态变化。 相似文献