排序方式: 共有23条查询结果,搜索用时 15 毫秒
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FU Ding-Wei ;SONG Ji-Rong ;REN Ying-Hui ;YAN Biao ;LU Xing-Qiang ;HU Huai-Ming 《结构化学》2008,27(5):535-538
A copper(Ⅱ) complex Cu(L)2(NO3)2 constructed by the L (L = N-(4,6-dimethoxylpyrimidin)-N'-(ethoxycarbonyl)thiourea) ligand crystallizes in monoclinic, space group C2/c with a = 16.2416(16), b = 9.1385(7), c = 22.0008(18) A, β = 108.077(2)°, V = 3104.3(5) A^3, Dc = 1.627 g/cm^3, Z = 4, C20H28CuN10O14S2, Mr = 760.18,μ(MoKa) = 0.920 mm^-1, F(000) = 1564, R = 0.0471 and wR = 0.1284 for 2239 observed reflections (I 〉 2σ(I)). X-ray diffraction shows the existence of weak complementary intramolecular N-H...O (DA) hydrogen bonds which further strengthen the coordination from the two L ligands with the Cu(Ⅱ) ion, intermolecular C-H...O hydrogen bonds and weak π...π stacking interactions, leading to the formation of a multi-dimensional supramolecular network. 相似文献
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Chang-Sheng Kuai Ding-Wei Ji Chao-Yang Zhao Heng Liu Dr. Yan-Cheng Hu Prof. Dr. Qing-An Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(43):19277-19282
A method for the regiodivergent and stereoselective hydrosilylation of the basic industrial feedstock isoprene with unactivated silanes has been developed using earth-abundant iron catalysts. The manipulation of regioselectivity relies on fine modification of the coordination geometry of the iron center. While a bidentate pyridine imine ligand promoted the formation of allylic silanes through 4,1-addition, selectivity for the 3,4-adduct homoallylic silanes was observed with a tridentate nitrogen ligand. Experimental studies and analysis were carried out to elucidate the reaction mechanism and the factors enabling manipulation of the regioselectivity. This study contributes to the art of regioselectivity control in alkene hydrofunctionalization. 相似文献
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本文 以 Ⅱ类超导体 Abrikosov磁通结构理论为依据,采用典型的热力学方法,论证了 Ⅱ类超导体在 Hc1相变点由 Meissner态到低场混合态的相变,以及在 Hc2相变点由高场混合态到正常态的相变性质.我们的论证结果表明:Ⅱ类超导体在He相交点与He相变点的相变均为二级相变,两相的比热差方程直接依赖相平衡曲线关系,且理论值与实验值比较的一致性约为90%.1引言 I类超导体的热力学一级相变理论已被大家所熟知,相比之下,Ⅱ类超导体热力学相变理论还有待于进一步发展与完善.曾在六十年代, Morin等人… 相似文献
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The variations of flow structure and heat transfer characteristics of impinging air jets with respect to mesh solidity are
compared for two mesh screen locations at small nozzle-to-plate spacings. Results show that the uniform incoming flow structure
produces higher heat transfer rates in the impingement region. The heat transfer enhancement largely depends on nozzle-to-plate
spacing, mesh solidity, and jet Reynolds number. The mechanism of heat transfer enhancement is analyzed in light of the field
synergy principle. 相似文献
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Ding-Wei Hong Po-Liang Lai Kuan-Lin Ku Zhi-Teng Lai I.-Ming Chu 《Polymer Degradation and Stability》2013
In this study, a biodegradable in situ gel-forming controlled drug delivery system based on a thermosensitive methoxy polyethylene glycol-co-poly (lactic acid-co-aromatic anhydride) (mPEG-PLCPPA) hydrogel was studied. The hydrogels were formed by micelle aggregation with rising temperature. The hydrogels underwent a temperature-dependent sol–gel–sol transition, which was a flowing sol at ambient temperature and a non-flowing gel at the physiological body temperature. The residual weight and pH value changes after degradation and the viscosity properties of the hydrogel were investigated. The in vitro release behavior of vancomycin from the mPEG-PLCPPA hydrogels at different concentrations was also investigated. The results showed that the mPEG-PLCPPA amphiphilic copolymer could self-assemble to form micelles at low concentrations, and that the particle sizes gradually increased with increasing temperature. The hydrogel maintained a stable degradation rate and provided a moderate pH microenvironment after degradation for 30 days. Vancomycin sustained a stable release profile from the hydrogel over a 10-day period. Furthermore, good biocompatibility was proven by MTT assay and live and dead test. Therefore, the mPEG-PLCPPA hydrogel shows promise as an injectable local antibiotic delivery system. 相似文献
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Ting-Ting Song Yong-Kang Mei Yan Liu Xiao-Yu Wang Shi-Yu Guo Ding-Wei Ji Boshun Wan Weiming Yuan Qing-An Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(2):e202314304
Bridged benzazepine scaffolds, possessing unique structural and physicochemical activities, are widespread in various natural products and drugs. The construction of these skeletons often requires elaborate synthetic effort with low efficiency. Herein, we develop a simple and divergent approach for constructing various bridged benzazepines by a photocatalytic intermolecular dearomatization of naphthalene derivatives with readily available α-amino acids. The bridged motif is created via a cascade sequence involving photocatalytic 1,4-hydroaminoalkylation, alkene isomerization and cyclization. Interestingly, the diastereoselectivity can be regulated through different reaction modes in the cyclization step. Moreover, aminohydroxylation and its further bromination have also been demonstrated to access highly functionalized bridged benzazepines. Preliminary mechanistic studies have been performed to get insights into the mechanism. This method provides a divergent synthetic approach for construction of highly functionalized bridged benzazepines, which have been otherwise difficult to access. 相似文献
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C. C. Yang Choong-Wen Lay Ming-Shan Lin Ding-Wei Huang 《Optical and Quantum Electronics》1996,28(10):1217-1227
Owing to differences in the selection rules of electron transitions between TE and TM modes in a quantum well structure, and optical amplifier with such a structure manifests linear birefringence and anisotropy of gain-absorption saturation. The anisotropy leads to the evolution of power-dependent polarization in the optical amplifier. We demonstrate experimentally efficient non-linear self-switching based on this phenomenon in an InGaAs/GaAs single quantum well amplifier. Also, by utilizing the non-linear polarization evolution, we show numerically passive mode-locking of a semiconductor laser with a ring cavity. 相似文献