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951.
Dr. Shengxian Cheng Jing Ouyang Dr. Muqing Li Yingxue Diao Jiachen Yao Fengxing Li Yat-For Lee Dr. Herman Ho-Yung SUNG Prof. Dr. Ian Williams Prof. Dr. Zhengtao Xu Prof. Dr. Yangjian Quan 《Angewandte Chemie (International ed. in English)》2023,62(25):e202300993
Photoinduced metal–organic framework (MOF) enabled heterogeneous thiol catalysis has been achieved for the first time. MOF Zr-TPDCS-1 , consisting of Zr6-clusters and TPDCS linkers (TPDCS=3,3′′,5,5′′-tetramercapto[1,1′:4′,1′′-terphenyl]-4,4′′-dicarboxylate), effectively catalyzed the borylation, silylation, phosphorylation, and thiolation of organic molecules. Upon irradiation, the fast electron transfer from TPDCS to Zr6-cluster is believed to facilitate the formation of the thiyl radical, a hydrogen atom transfer catalyst, which competently abstracts the hydrogen from borane, silane, phosphine, or thiol for generating the corresponding element radical to engender the chemical transformations. The elaborate control experiments evidenced the generation of thiyl radicals in MOF and illustrated a radical reaction pathway. The gram-scale reaction worked well, and the product was conveniently separated via centrifugation and vacuum with a turnover number (TON) of ≈3880, highlighting the practical application potential of heterogeneous thiyl-radical catalysis. 相似文献
952.
Accurate theoretical estimates of static and dynamic dipole polarizabilities are reported for the ground and excited states of hydrogen atom confined at the center of a spherical “box” with impenetrable walls using a novel theoretical algorithm that combines the variational–perturbation approach with an appropriately adapted mapped Fourier grid method and uniformly maintains the numerical accuracy. A variation of computed polarizabilities is observed as a function of the number of grid points. However, rapid convergence to their correct values, even far into the anomalous dispersion region, is achieved by an extrapolation procedure to the limit of an infinitely large number of grid points using a small number of the lowest‐order Padé approximants. It is shown that dipole polarizabilities strongly depend upon the electronic state and the radius of confinement. In particular, the static polarizability of 2s state changes sign under strong confinement. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 相似文献
953.
954.
In this article, an acoustic cavitation engineered novel approach for the synthesis of TiO2, cerium and Fe doped TiO2 nanophotocatalysts is reported. The prepared TiO2, cerium and Fe doped TiO2 nanophotocatalysts were characterized by XRD and TEM analysis to evaluate its structure and morphology. Photo catalytic performance of undoped TiO2 catalyst was investigated for the decolorization of crystal violet dye in aqueous solution at pH of 6.5 in the presence of hydro dynamic cavitation. Effect of catalyst doping with Fe and Ce was also studied for the decolorization of crystal violet dye. The results shows that, 0.8% of Fe-doped TiO2 exhibits maximum photocatalytic activity in the decolorization study of crystal violet dye due to the presence of Fe in the TiO2 and it may acts as a fenton reagent. Kinetic studies have also been reported for the hybrid AOP (HAOP) that followed the pseudo first-order reaction kinetics. 相似文献
955.
全附体ONRT船模在波浪中自航的数值模拟 总被引:1,自引:0,他引:1
采用基于重叠网格技术的CFD方法数值研究了全附体ONRT船模在迎浪工况中自航的水动力特性.文中数值计算采用自主开发的面向船舶与海洋工程的CFD求解器naoe-FOAM-SJTU.自航计算中船体运动及螺旋桨转动等通过重叠网格技术完成,波浪环境则采用求解器中的三维数值造波和消波模块实现.计算中自航船模的螺旋桨转速通过静水自航数值计算得出,波浪工况计算采用东京2015 CFD会议中标准算例进行设置.数值计算结果,如船体运动、实时航速变化等,与试验数据进行了对比分析.此外,给出了数值预报的推力和扭矩系数,并且通过详细的流场信息来分析和解释了船模在波浪中自航过程中的水动力变化情况.数值预报结果同试验值吻合较好,说明采用当前结合重叠网格技术和CFD的数值方法可以很好地预报波浪中自航问题. 相似文献
956.
针对直线段与圆弧连接处的过渡,采用微小线段插补进行处理;通过前瞻分析的方法,控制直线段与圆弧段过渡处的进给速度提前减速,有效地减少了直线与圆弧过渡处的加工误差,建立混合S型双向加减速曲线模型,实现了圆弧段拐角处速度的控制.为了更好地优化数控刀具的加工时间,改进S型加速曲线原来加速缓慢耗时的前半部分,建立非零启动S型曲线加减速模型,从而减少启动时间,这种改进极大地优化刀具在走圆弧时的时间及平稳性. 相似文献
957.
抽样调查是获取社会经济调查数据的主要手段,其抽样设计一般采用分层多阶段不等概的抽样设计。但是,在抽样设计和实际抽样中,人们往往忽视末端样本个体的抽样,本文主要基于中国家庭动态跟踪调查数据对末端样本的概率抽样方法进行比较研究。 相似文献
958.
959.
利用高压原位红外光谱法实时跟踪监测了CH_3NH_3PbI_3在高压氮气以及不同含量氧气气氛中加热时的变化规律.发现CH_3NH_3PbI_3对氧气十分敏感,当氮气中含有1%(体积分数)的氧气时,CH_3NH_3PbI_3加热到150℃发生分解;继续提高氧气含量到21%,温度升高到100℃时CH_3NH_3PbI_3即发生分解;若在常压高纯氮气中加热,其分解温度则能提高到250℃;若将氮气压力提高到4.0 MPa,CH_3NH_3PbI_3的分解温度进一步提高到270℃.实验结果表明,提高压力和减少环境中的氧含量是改善钙钛矿复合半导体稳定性的有效方法.相应地,复合半导体光电子器件的热处理过程可以在更高的温度下进行,从而有希望获得性能更加优良的钙钛矿复合半导体光电子器件. 相似文献
960.
Solution of the “Classical” Schrödinger equation for a driven symmetric triple well: A comparison with its classical counterpart
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Susmita Kar Pratim Kumar Chattaraj 《International journal of quantum chemistry》2016,116(16):1224-1243
The behavior of a driven symmetric triple well potential has been studied by developing an algorithm where the well‐established Bohmian mechanics and time‐dependent Fourier Grid Hamiltonian method are incorporated and the quantum theory of motion (QTM) phase space structures of the particle are constructed, both in “nonclassical” and “classical” limits. Comparison of QTM phase space structures with their classical analogues shows both similarity as well as dissimilarities. The temporal nature and the spatial symmetry of applied perturbation play crucial roles in having similar phase space structures. © 2016 Wiley Periodicals, Inc. 相似文献