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771.
Bing Han Run-Feng HanYu-Wei Ren Xiao-Yong DuanYi-Chuan Xu Wei Zhang 《Tetrahedron》2011,67(31):5615-5620
4-Substituted dihydropyrimidinones and dihydropyrimidines were first efficient aerobic oxidized to the corresponding pyrimidinones and pyrimidines, respectively, in high yields by molecular oxygen in the presence of catalytic amount of N-hydroxyphthalimide (NHPI) and Co(OAc)2 in a mild and environmental benign condition. 相似文献
772.
We reported an interfacial self-assembly of regularly layered porous poly(4-vinylpyridine)(P4VP) films at the interfaces of water-chloroform or -dichloroethane.The porous diameters were in the range from hundred nanometers to several micrometers.It was revealed that formation of such kind of porous materials was solvent dependent.Moreover,cyclic Ag nanoparticles could be grown in the porous P4VP films to form Ag-P4VP nanohybrids under radiation. 相似文献
773.
Catalyzed by ytterbium(III) triflate hydrate [Yb(OTf)3.xH20], the Michael addition and cyclocondensation of α,β-unsaturated ketones with active methylene compounds to afford the 1,4-adducts and benzo[b]pyran derivatives, respectively were studied. 相似文献
774.
775.
学生空间思维的不足影响了学生对空间曲面的理解和重积分的学习。本文通过二个实例,重点讨论了用MATLAB动态生成空间图形的技巧。 相似文献
776.
研究了CID-IP-AES用于测定高纯物质的分析性能。以高纯LiOH为对象,研究了低浓度范围内分析线的选择,标准曲线的特性,探讨了直接用于高纯物质分析的检测能力及可行性。 相似文献
777.
This paper gives a survey of works on the theory of toroidal shells which were done by our two universities in recent years.
This paper was supported by DAAD Germany 相似文献
778.
A microelectromechanical systems (MEMS) micromirror is demonstrated in this paper. The micromirror is actuated by an electrostatic force and can achieve a large out of plane stroke by eliminating the electrostatic pull-in effect. The micromirror consists of a mirror of 400 μm by 400 μm in the center, a spring and three fixed bottom electrodes each side. Design principles and the analytical model are both developed, and they are verified by finite element analysis (FEA). The resonant frequency for the piston movement of the designed micromirror is about 2.5 kHz by FEA simulation. The micromirror prototype has been fabricated by a surface micromachining process and it is successfully tested using a microsystem analyzer. An out of plane stroke of 1.65 μm is observed at 100 V and it agrees well with the predicted result from analytical model. 相似文献
779.
A series of novel derivatives of 4, 5, 6, 7-tetrahydrothieno [3,2-c] pyridine were synthesized and structurally characterized by 1H NMR and MS. Their in vivo anti-platelet aggregation activities were evaluated. A 3D-QSAR was performed using the CoMFA and the CoMSIA. This model provided useful guidelines for novel anti-platelet thienopyridines design. 相似文献
780.
Lian Peng Tong ;Jing Nan Cui ;Wei Min Ren ;Xing Yong Wang ;Xu Hong Qian 《中国化学快报》2008,19(10):1179-1182
Regio- and enantioselective reduction of substituted acenaphthenequinones were conducted under mild reaction conditions using plant enzymatic systems. A screening of 15 plants allowed the selection of two suitable plants fulfilling enantiocomple- mentarity. The (+)- and (-)-mono hydroxyacenaphthenones were achieved with high conversion and good enantiomeric purity using peach (Prunus persica (L.) Batsch., conversion 98%, 71% ee) and carrot (Daucus carota L., conversion 95%, 81% ee), respectively. 相似文献