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991.
992.
Jin Liu Xianxue Wang Han Guo Xiaokang Shi Xiaoyu Ren Guosheng Huang 《Tetrahedron》2012,68(5):1560-1565
A novel NH4OAc/CuBr(PPh3)3-induced intermolecular Pummerer-type reaction between free (NH)-indoles and dimethylsulfoxide is first reported, which offers the 3-methylthiomethyl substituted indoles conveniently and efficiently. 相似文献
993.
An efficient synthetic method for the pentasubstituted pyrroles was successfully developed via the one-pot domino reactions of arylamines, acetylenedicarboxylates, and 3-phenacylideneoxindoles. The reaction mechanism involved the sequential Michael addition and ring closure of the in situ generated β-active enamino ester. 相似文献
994.
995.
SU CaiHong 《中国科学:物理学 力学 天文学(英文版)》2014,57(5):950-962
Up to now,the most widely used method for transition prediction is the one based on linear stability theory.When it is applied to three-dimensional boundary layers,one has to choose the direction,or path,along which the growth rate of the disturbance is to be integrated.The direction given by using saddle point method in the theory of complex variable function is seen as mathematically most reasonable.However,unlike the saddle point method applied to water waves,here its physical meaning is not so obvious,as the frequency and wave number may be complex.And on some occasions,in advancing the integration of the growth rate of the disturbance,up to a certain location,one may not be able to continue the integration,because the condition for specifying the direction set by the saddle point method can no longer be satisfied on the basis of continuously varying wave number.In this paper,these two problems are discussed,and suggestions for how to do transition prediction under the latter condition are provided. 相似文献
996.
997.
Huilan Su Fang Song Qun Dong Tuoqi Li Xin Zhang Di Zhang 《Applied Physics A: Materials Science & Processing》2011,104(1):269-274
A simple and versatile technique was developed to prepare hierarchical ZnO single crystals by introducing eggshell membrane
(ESM) to a bio-inspired approach. Based on the control of nucleation and gestation, ZnO nanocrystallites could grow at three
dimensions into polyhedral single crystals through a surface sol-gel process followed by a calcination treatment. Different
from traditional wet chemical techniques, our synthetic process depends more on the restrictive or directing functions of
the ESM biomacromolecules. The hierarchical ZnO nanostructures doped with polyhedral single crystallites could be desirable
for catalysts, photoelectrochemical devices, especially solar cells. 相似文献
998.
In a satellite optical communication system, the pointing error is an important factor that strongly influences the system performance. For periscope-type satellite optical communication terminals, installation errors of 45° plane mirrors in the coarse point apparatus (CPA) can lead to pointing errors. In this respect, we classify the installation errors of two 45° plane mirrors in the system and derive the corresponding ??transfer?? matrices to describe them. Furthermore, we establish mathematical models of the pointing error caused by installation errors of 45° plane mirrors. These models allow one to calculate and compensate the pointing errors in periscope-type satellite optical communication terminals. The results of our simulations show that the pointing errors vary with the elevation axis angle but do not depend on the azimuth axis angle. Compared to the side-angle error, the slope-angle error brings a larger pointing error. However, the mathematical model we developed allows one to compensate more than 99.9?% of the overall pointing error. The present work provides a theoretical basis for the design of periscope-type satellite optical communication terminals. 相似文献
999.
1000.