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961.
Wu Bin Lyu Pin Wang Kaixuan Qiu Xiaoyan Liu Taifeng Zhang Fang Li Hexing Xiao Shengxiong 《Research on Chemical Intermediates》2018,44(10):6327-6337
Research on Chemical Intermediates - Upon oxidation, a graphyne-like porous carbon-rich network (GYLPC), which is a two-dimensional carbon material consisting of sp- and sp2-hybridized carbon atoms... 相似文献
962.
963.
Tailorable PC71BM Isomers: Using the Most Prevalent Electron Acceptor to Obtain High‐Performance Polymer Solar Cells
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Xin‐Xing Zhan Xin Zhang Si‐Min Dai Shu‐Hui Li Xu‐Zhai Lu Dr. Lin‐Long Deng Prof. Su‐Yuan Xie Prof. Rong‐Bin Huang Prof. Lan‐Sun Zheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(52):18709-18713
Despite being widely used as electron acceptor in polymer solar cells, commercially available PC71BM (phenyl‐C71‐butyric acid methyl ester) usually has a “random” composition of mixed regioisomers or stereoisomers. Here PC71BM has been isolated into three typical isomers, α‐, β1‐ and β2‐PC71BM, to establish the isomer‐dependent photovoltaic performance on changing the ternary composition of α‐, β1‐ and β2‐PC71BM. Mixing the isomers in a ratio of α/β1/β2=8:1:1 resulted in the best power conversion efficiency (PCE) of 7.67 % for the polymer solar cells with PTB7:PC71BM as photoactive layer (PTB7=poly[[4,8‐bis[(2‐ethylhexyl)oxy]benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl][3‐fluoro‐2‐[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl]]). The three typical PC71BM isomers, even though sharing similar LUMO energy levels and light absorption, render starkly different photovoltaic performances with average‐performing PCE of 1.28–7.44 % due to diverse self‐aggregation of individual or mixed PC71BM isomers in the otherwise same polymer solar cells. 相似文献
964.
Funding and investment decisions in a stochastic defined benefit pension plan with regime switching*
In this paper, we consider a continuous-time Markov regime-switching model for a pension plan with a collective defined benefit character. In particular, we focus on optimal funding and asset allocation problem for a fund manager who wants to maximize the expected utility of the difference ratio between the benefit and contribution rates to the total salary until ruin. Using the techniques and methods of stochastic control, we present a system of Hamilton–Jacobi–Bellman equations for this optimization problem and establish a verification theorem. In the special cases of logarithmic and power utility, we solve the problem explicitly and present some numerical examples to illustrate our results. 相似文献
965.
The enhanced biological activities of three Zn (II) complexes based on different 1,2,4‐triazole fungicides
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Guo‐yu Ren Jie Li Xu‐zhan Wei Jin‐hua Zhou Biao Yan Zhao‐qi Guo Ying‐hui Ren Xiao‐hong Sun Hai‐xia Ma 《应用有机金属化学》2018,32(9)
In order to screen effective fungicides, three Zn (II) complexes, [Zn L 1 4 (NO3)2]·2H2O·2EtOH ( 1 ), [Zn L 2 4 (NO3)2] ( 2 ), and [Zn L 3 4 (DMF)2](NO3)2 ( 3 ), ( L 1 = paclobutrazol, L 2 = diniconazole, and L 3 = hexaconazole), were synthesized and characterized by elemental analysis, FT‐IR spectroscopy, and single‐crystal XRD. The antifungal activities of these complexes were then evaluated against four selected fungi using the mycelial growth rate method. The resulting data indicate that all the complexes show the enhanced antifungal activities than the corresponding ligand and mixtures. And, the interactions between the metal salt and ligands in the three complexes seem to be synergistic. According to the study of the influence of the structures on the activity, complex 2 with C=C linkage and 2,4‐dichlorophenyl moieties enhances the bioactivity significantly, especially against Wheat gibberellic ( II ). Density functional theory (DFT) calculations were carried out to help explain the enhanced bioactivity of the Zn (II) complexes. Meanwhile, all complexes are excellent grow‐regulators, especially complex 3 . The resulting data show that the complexes based on triazole fungicides have the potential applications in agriculture. 相似文献
966.
Ethylene polymerization with long‐lifetime monopendant thienyl‐substituted group 4 metallocenes
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A series of group 4 metallocenes (RCp)[Cp―(bridge)―(2‐C4H3S)]MCl2 [M = Ti ( C1 , C2 , C3 , C4 ); M = Zr ( C5 , C6 , C7 , C8 )] bearing a pendant thiophene group on a cyclopentadienyl ring have been synthesized, characterized and tested as catalyst precursors for ethylene polymerization. The molecular structures of representative titanocenes C2 and C4 were confirmed by single‐crystal X‐ray diffraction and revealed that both complexes exist in an expected coordination environment for a monomeric bent metallocene. No intramolecular coordination between the thiophene group and the titanium center could be observed in the solid state. Upon activation by methylaluminoxane (MAO), titanocenes C1 , C2 , C3 , C4 showed moderate catalytic activities and produced high‐ or ultra‐high‐molecular‐weight polyethylene (Mv 70.5–227.1 × 104 g mol?1). Titanocene C3 is more active and long‐lived, with a lifetime of nearly 9 h at 30 °C. At elevated temperatures of 80–110 °C, zirconocenes C5 , C6 , C7 , C8 displayed high catalytic activities (up to 27.6 × 105 g PE (mol Zr)?1 h?1), giving high‐molecular‐weight polyethylene (Mv 11.2–53.7 × 104 g mol?1). Even at 80 °C, a long lifetime of at least 2 h was observed for the C8/MAO catalyst system. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
967.
968.
Computational insight into asymmetric uranyl‐salophen coordinated with α, β‐unsaturated aldehydes and ketones
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Wen‐Bo Lan Xiao‐Feng Wang Li‐Ping He Yan‐Bin Meng Jun Li Bin Qiu Chang‐Ming Nie 《应用有机金属化学》2018,32(3)
The study of the catalytic activity and activation mechanism of asymmetric uranyl‐salophens with α, β‐unsaturated aldehydes or α, β‐unsaturated ketones, is a research hotspot. In this paper, the complexes of the uranyl–salophen(U‐S) modified by unilateral benzene, coordinated with cyclohexenone, cyclopentenone and acrolein, were investigated using density functional theory calculations at the level of B3LYP/6‐311G(d, p) basis set. The results showed that the uranyl‐salophen(U‐S) weakened the large π bond between C = C and C = O of the α, β‐unsaturated aldehydes and ketones, making the unsaturated aldehydes and ketones activated. In addition, the molecular‐recognition selectivity of the asymmetrical uranyl‐salophen for cyclohexenone and cyclopentenone were much higher than for acrolein. 相似文献
969.
970.
Xingxun Liu Hongxin Ma Long Yu Ling Chen Zhen Tong Pei Chen 《Journal of Thermal Analysis and Calorimetry》2014,115(1):659-665
Thermal oxidation degradation of high-amylose (80 %) cornstarch has been studied using thermogravimetry analyser coupled to Fourier transform infrared spectroscopy (TG-FTIR). The linear structure of amylose provides a modal material to understand how the starch microstructure affects on the decomposition mechanisms. Kinetics of the thermal oxidation has been studied using different methods. It is found that the thermal oxidation degradation is more complex than thermal degradation, thermal oxidation degradation kinetics of the starch can be interpreted in terms of multi-step degradation mechanism, the activation energies obtain from Flynn–Wall–Ozawa (F–W–O) method and modified Coats–Redfern method are in good agreement. TG-FTIR and FTIR results confirm that the thermal oxidation mechanism of starch is a process containing long chain scission and glowing combustion. 相似文献