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71.
Coulter MM Kou KG Galligan B Dong VM 《Journal of the American Chemical Society》2010,132(46):16330-16333
We report a Rh-catalyzed, regio- and enantioselective intermolecular olefin hydroacylation under mild conditions. Hydroacylations between homoallylic sulfides, containing a substrate-bound directing group, and salicylaldehyde derivatives occur in the presence of a spiro-phosphoramidite ligand, (R)-SIPHOS-PE, to give α-branched ketones in >20:1 selectivity and up to 97% ee. Our conditions are also applicable to the asymmetric intermolecular hydroacylation of 1,2-disubstituted olefins. 相似文献
72.
X. F. Yang D. Y. Shen T. Zhao H. Chen J. Zhou J. Li H. M. Kou Y. B. Pan 《Laser Physics》2011,21(6):1013-1016
We report on a high power polycrystalline Er:YAG ceramic laser in-band pumped by a cladding-pumped Er, Yb fiber laser wavelength
locked at 1532 nm with a volume Bragg grating. Using 1.0 at % Er3+-doped ceramic as the gain medium and an output coupler of 10% transmission, the laser had a threshold pump power of ∼1.5
W and generated 11 W of continuous-wave output at 1645 nm for 23.3 W of incident pump power at 1532 nm, corresponding to a
slope efficiency with respect to incident pump power of 51%. 相似文献
73.
Li Jiang Shan Du Ren-Gang Wan Jun Kou Han Zhang Han-Zhuang Zhang 《Optics Communications》2011,284(10-11):2509-2514
The entanglement of a two-level atom with its spontaneously emitted photon embedded in double-band anisotropic photonic crystal has been investigated via the method of the quantum entropy. Different from the case in an isotropic crystal or in vacuum, the entanglement has symmetrical properties and much slower entanglement rate near the two band edges. Moreover, as a result of the atom-photon bound states by the virtue of the localization around the emitting atom, the degree of the entanglement gradually increases, achieves the maximum and then sharply reduces to zero on the boundary of forbidden band gap as the atomic frequency moves from the center of the band gap to either of the band edges. 相似文献
74.
Jun Kou Ren-Gang Wan Shang-Qi Kuang Li Jiang Liang Zhang Zhi-Hui Kang Hai-Hua Wang Jin-Yue Gao 《Optics Communications》2011,284(6):1603-1607
The electromagnetically induced transparency (EIT) and its dispersion properties in a four-level inverted-Y atomic system are investigated. The absorption spectrum of a weak probe field shows two EIT windows (dark resonances) whose location, width, and depth can be controlled by manipulating the parameters of the coupling fields; the corresponding dispersion properties are also measured by using a Mach-Zehnder interferometer. The experimental measurements agree well with the theoretical calculations. This kind of system can find important applications in two-channel quantum communication and information storage. 相似文献
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76.
We analyze a combined method consisting of the mixed finite element method for pressure equation and the discontinuous Galerkin method for saturation equation for the coupled system of incompressible two‐phase flow in porous media. The existence and uniqueness of numerical solutions are established under proper conditions by using a constructive approach. Optimal error estimates in L2(H1) for saturation and in L ∞ (H(div)) for velocity are derived. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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79.
We prove the existence and uniqueness of a global solution of a damped quasilineat hyperbolic equatiion. We apply a method based on a special integral inequality, to show that the solution decays exponentially, and to obtain precise estimates of the constants in estimates. 相似文献
80.
本文利用EXAFS(Extended X-ray Absorption Fine Structure)对铑基担载液相催化剂(Supported Liquid Phase Catalyst SLPC)进行了结构表征。采用球面波理论对SLPC的EXAFS结果进行了多参数拟合。结果表明,在新鲜催化剂上,铑络合物以二聚物形式存在,推测其结构为(PPh_3)_2(CO)Rh-Rah(CO)(PPh_3)_2,Rh-C-O偏离共线分布。在经过羰化反应活化的活性SLPC上,铑络合物为单核的HRh(CO)_2(PPh_3)或Rh(CO)_2(PPh_32)_3。文中还讨论了SLPC的XRD谱。 相似文献