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41.
Zhen-Xing ZhangBaolin Wu Bin WangTie-Hai Li Peng-Fei ZhangLi-Na Guo Wen-jun WangWei Zhao Peng George Wang 《Tetrahedron letters》2011,52(29):3802-3804
A novel and facile synthesis of a series of the biologically significant iminosugar derivatives including 2-deoxynojirimycin, Miglustat and Miglitol is reported. The synthesis features a strategic double inversion mechanism for securing the desired stereochemistry at C5 position of such glucose-type carbohydrate mimetics, representing a practical and remarkable improvement on the previously reported method that suffers from the loss of the stereo-control during the reaction process. 相似文献
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AbstractAn amide-assisted arene nitration is presented, and both mono- and dinitration of protected anilines could be effected by using NaNO2 and NaNO3 as the mono- and bisnitrating agents, respectively. This divergent synthesis is transition-metal- and acid-free, and features a broad substrate scope, low cost, and ortho–para selectivity. 相似文献
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Daoyuan Zheng Yurong Guo Mingxing Zhang Xia Feng Lina Zhu Lijuan Qiu Xiaoning Jin Guangjiu Zhao 《Journal of computational chemistry》2020,41(10):976-985
Organic semiconductors (OSCs) materials are currently under intense investigation because of their potential applications such as organic field-effect transistors, organic photovoltaic devices, and organic light-emitting diodes. Inspired by the selenization strategy can promote anisotropic charge carrier migration, and selenium-containing compounds have been proved to be promising materials as OSCs both for hole and electron transfer. Herein, we now explore the anisotropic transport properties of the series of selenium-containing compounds. For the compound containing Se Se bond, the Se Se bond will break when attaching an electron, thus those compounds cannot act as n-type OSCs. About the different isomer compounds with conjugated structure, the charge transfer will be affected by the stacking of the conjugated structures. The analysis of chemical structure and charge transfer property indicates that Se-containing materials are promising high-performance OSCs and might be used as p-type, n-type, or ambipolar OSCs. Furthermore, the symmetry of the selenium-containing OSCs will affect the type of OSCs. In addition, there is no direct relationship between the R groups with their performance, whether it or not as p-type OSCs or n-types. This work demonstrates the relationship between the optoelectronic function and structure of selenium-containing OSCs materials and hence paves the way to design and improve optoelectronic function of OSCs materials. 相似文献
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利用前驱物形貌导向法,成功制备了Co9S8/MoS2异质结构催化剂,该催化剂在碱性析氢反应(HER)中表现出优异的催化活性及稳定性,其在10 mA·cm-2处的过电势仅为84 mV.通过X射线粉末衍射(XRD)、透射电子显微镜(TEM)、电子自旋共振(ESR)、拉曼光谱(Raman)、X射线光电子能谱(XPS)和同步辐射(XAFS)等表征,证明了CoS2/MoS2在H2氛围下煅烧形成Co9S8/MoS2的过程中,CoS2中Co的配位模式从部分八面体向Co9S8中的四面体转变,这种转变可活化MoS2的惰性平面,从而使其更有利于吸附H*.除此之外,接触角数据表明:该催化剂具有良好的亲水性,有利于电解液渗透及气体分子的迅速扩散,从而促进HER反应速率.由于异质结构间具有强烈的相互作用,该催化剂可表现出良好的结构稳定性.本工作基于Co9S8/MoS2异质结构的成功构筑及对其HER催化机理的充分探讨,为后续硫化物异质结及其在电催化中的应用提供了良好的思路和研究基础. 相似文献
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Many real life problems can be stated as a minimax optimization problem, such as the problems in economics, finance, management, engineering and other fields. In this paper, we present an algorithm with nonmonotone strategy and second-order correction technique for minimax optimization problems. Using this scheme, the new algorithm can overcome the difficulties of the Maratos effect occurred in the nonsmooth optimization, and the global and superlinear convergence of the algorithm can be achieved accordingly. Numerical experiments indicate some advantages of this scheme. 相似文献
49.
Tzyy-Chyang LuJyh-Ching Juang 《Applied mathematics and computation》2011,218(6):2516-2532
This work presents the evolutionary quantum-inspired space search algorithm (QSSA) for solving numerical optimization problems. In the proposed algorithm, the feasible solution space is decomposed into regions in terms of quantum representation. As the search progresses from one generation to the next, the quantum bits evolve gradually to increase the probability of selecting the regions that render good fitness values. Through the inherent probabilistic mechanism, the QSSA initially behaves as a global search algorithm and gradually evolves into a local search algorithm, yielding a good balance between exploration and exploitation. To prevent a premature convergence and to speed up the overall search speed, an overlapping strategy is also proposed. The QSSA is applied to a series of numerical optimization problems. The experiments show that the results obtained by the QSSA are quite competitive compared to those obtained using state-of-the-art IPOP-CMA-ES and QEA. 相似文献
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讨论了机构投资者的最优持仓策略问题,假设证券价格服从几何布朗运动,以均值方差效用为目标函数,得到了最优持仓策略所满足的二阶微分方程,并由差分法得到其数值解.最后,由参数的敏感性分析知:最优持仓策略与瞬时冲击、市场波动率及风险厌恶系数等参数有关,并分析了参数变化对最优持仓策略的影响. 相似文献