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101.
Shaogan Niu Lifen Zhang Jian Zhu Wei Zhang Zhenping Cheng Xiulin Zhu 《Journal of polymer science. Part A, Polymer chemistry》2013,51(5):1197-1204
Well‐defined polyacrylonitrile (PAN) of high viscosity‐average molecular weight (Mη = 405,100 g/mol) was successfully synthesized using reversible addition‐fragmentation chain transfer polymerization. The polymerization exhibits controlled characters: molecular weights of the resultant PANs increasing approximately linearly with monomer conversion and keeping narrow molecular weight distributions. The addition of 0.01 equiv (relative to monomer acrylonitrile) of Lewis acid AlCl3 in the polymerization system afforded the obtained PAN with an improved isotacticity (by 8%). In addition, the influence of molecular weights and molecular weight distributions of PANs on the morphology of the electrospun fibers was investigated. The results showed that, under the same conditions of electrospinning, average diameter (247–1094 nm) of fibers increased with molecular weights of PANs, and it was much easier to get “uniform” diameter fibers while using PANs with narrow molecular weight distributions as the precursor of electrospinning. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
102.
C. P. Cheng M. H. Tang Z. H. Tang Y. C. Zhou 《Journal of Sol-Gel Science and Technology》2013,68(2):346-350
Magnetoelectric (ME) xLa0.6Ca0.4MnO3–(1 ? x)Bi3.4Nd0.6Ti3O12 (LCMO–BNT) composite thin films have been prepared by a sol–gel process and spin-coating technique. The effects of LCMO content on the microstructure, leakage current density, ferroelectric properties, fatigue endurance and ME voltage coefficient of LCMO–BNT thin films derived by sol–gel method were studied. It was found that the composite thin films have better fatigue endurance properties and lower leakage current densities compared with pure BNT thin films, as well as large ME voltage coefficients. 相似文献
103.
Wenbo Wu Dr. Guohua Xu Prof. Conggang Li Prof. Gui Yu Prof. Yunqi Liu Prof. Cheng Ye Prof. Jingui Qin Prof. Zhen Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(21):6874-6888
Through the combination of the divergent and convergent approaches, coupled with the utilization of the powerful Sharpless “click‐chemistry” reaction, two series of sulfonyl‐based high‐generation NLO dendrimers were conveniently prepared with high purity and in satisfactory yields. Thanks to the perfect three‐dimensional (3D) spatial isolation from the highly branched structure and the isolation effect of the exterior benzene moieties and the interior triazole rings, these dendrimers exhibited large second harmonic generation coefficient (d33) values up to 181 pm V?1, which, to the best of our knowledge, is the highest value so far for polymers containing sulfonyl‐based chromophore moieties. Meanwhile, compared with the nitro‐chromophore‐based analogues, their optical transparency and NLO stability were improved in a large degree, due to the lower dipole moment (μ) and the special main‐chain structure of sulfonyl‐based chromophore in these dendrimers. 相似文献
104.
Dr. Yan‐Fen Fang Prof. Wan‐Hong Ma Prof. Ying‐Ping Huang Prof. Gen‐Wei Cheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(9):3224-3229
The band structure of multicomponent semiconductor photocatalysts, as well as their reactivity distinction under different wavelengths of light, is still unclear. BiOBr, which is a typical multicomponent semiconductor, may have two possible valence‐band structures, that is, two discrete valence bands constructed respectively from O 2p and Br 4p orbitals, or one valence band derived from the hybridization of these orbitals. In this work, aqueous photocatalytic hydroxylation is applied as the probe reaction to investigate the nature and reactions of photogenerated holes in BiOBr. Three organic compounds (microcystin‐LR, aniline, and benzoic acid) with different oxidation potentials were selected as substrates. Isotope labeling (H218O as the solvent) was used to determine the source of the O atom in the hydroxyl group of the products, which distinguishes the contribution of different hydroxylation pathways. Furthermore, a spin‐trapping ESR method was used to quantify the reactive oxygen species (.OH and .OOH) formed in the reaction system. The different isotope abundances of the hydroxyl O atom of the products formed, as well as the reverse trend of the .OH/.OOH ratio with the oxidative resistance of the substrate under UV and visible irradiation, reveal that BiOBr has two separate valence bands, which have different oxidation ability and respond to UV and visible light, respectively. This study shows that the band structure of semiconductor photocatalysts can be reliably analyzed with an isotope labeling method. 相似文献
105.
106.
Xing-Wei Yang Xu-Jie Qin Yun-Li Zhao Paul K. Lunga Xiao-Nian Li Shi-Zhi Jiang Gui-Guang Cheng Ya-Ping Liu Xiao-Dong Luo 《Tetrahedron letters》2014
Three novel ring-fused monoterpenoid indole alkaloids, alstolactines A–C (1–3), were isolated from the long-term stored leaves of Alstonia scholaris. Their structures were identified on the basis of extensive spectroscopic data and X-ray diffractions. Moreover, the absolute configurations of these related structures were indicated by the crystal X-ray diffractions (Mo Kα) of 1a, a chlorinated derivative of 1. 相似文献
107.
108.
Chang Chi-I Chen Cheng-Chi Ko Horng-Huey Chen Jih-Jung Cheng Ming-Jen Chao Che-Yi Kuo Yueh-Hsiung 《Chemistry of Natural Compounds》2022,58(3):478-481
Chemistry of Natural Compounds - A new seco-abietanoid, 12-methoxy-7-oxo-6,7-secoabieta-8,11,13-trien-6-oic acid (1), and a known seco-abietanoid,12-hydroxy-6,7-secoabieta-8,11,13-triene-6,7-dial... 相似文献
109.
Chromatographia - In this study, a poly(glycidyl methacrylate) nanoparticle (PGMA NP)-coated column system with two antibiotics as selector was constructed for enantioseparation. The PGMA NP... 相似文献
110.