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71.
Hiroki Shigehisa 《Tetrahedron letters》2006,47(41):7301-7306
The first total synthesis of a spiro-isoquinoline alkaloid, (±)-annosqualine, was established by employing an enamide-phenol coupling of a 1-methylene-1,2,3,4-tetrahydroisoquinoline derivative with a hypervalent iodine reagent, where the formation of the phenoxide was recognized to be an essential step for the reaction of the phenolic hydroxyl group with the hypervalent iodine reagent leading to the formation of the desired product. 相似文献
72.
红外目标模拟器由红外目标图像发生器和投影光学系统组成。该红外光学系统是一个要求与2个导引光学系统的光学技术参数相匹配的长焦距、大视场和具有像方远心光路的中红外光学系统。叙述用于红外目标模拟器的红外耦合光学系统的设计原理,提出它与导引光学系统一起可组成放大倍率M=4.5×的红外投影光学系统,并指出IR CRT产生的图像通过红外投影光学系统可成像在导引接收器上。针对给出的红外耦合光学系统的设计特点和技术要求,光学材料选取硅(Si) 锗(Ge) 硅(Si),采用简单的柯克三片式结构完成光学系统设计。设计评价结果表明,该系统的光学性能和成像质量均满足设计指标要求。 相似文献
73.
Surajit Some 《Tetrahedron letters》2006,47(7):1221-1224
A convenient synthetic approach to substituted benzene derivatives by modified Ullmann cross-coupling of 2-bromobenzaldehyde and bromovinylaldehydes followed by intramolecular McMurry coupling has been developed. 相似文献
74.
在常温常压下采用新型旋转电极等离子体反应器,对辉光等离子体作用下的甲烷偶联反应制C2烃进行了研究。结果表明,甲烷偶联反应的主要产物为C2H2,占C2烃的80%以上,能量效率在5.6%~11.2%之间;增加H2含量可以提高CH4转化率和C2烃收率;在500~2200kJ•mol−1的能量密度范围内,CH4转化率随能量密度的增大而线性增加,C2烃收率随着能量密度的增加呈峰形变化趋势。 相似文献
75.
H. Barentzen 《Annalen der Physik》2006,15(9):684-698
The eigenvalues of the weakly coupled T ? t Jahn‐Teller problem are known for several decades, and the same holds also true for the eigenstates. These, however, are only given in the traditional position representation, which proves inconvenient if one attempts to extend the weak‐coupling treatment into the region of stronger coupling. Here the solution of the T ? t eigenvalue problem at weak coupling is derived in terms of creation and annihilation operators. This reformulation of the problem is nontrivial, since the algebraic form of the oscillator eigenvectors, being simultaneous angular‐momentum eigenstates, has been worked out only recently and is probably still widely unknown. The electronic and oscillator eigenstates are then coupled to form eigenvectors of the total angular momentum. Finally, in preparation for an extension of the weak‐coupling treatment, the action of the boson creation and annihilation operators on the oscillator eigenvectors is calculated, thus completing the algebraic approach to the weakly coupled T ? t system. 相似文献
76.
Noriko SUTO Makoto HARADA Jun IZUTSU Toshiyasu NAGAO 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2006,82(5):175-180
In order to accurately estimate the geomagnetic transfer functions in the area of the volcano Mt. Iwate (IWT), we applied the interstation transfer function (ISTF) method to the three-component geomagnetic field data observed at Mt. Iwate station (IWT), using the Kakioka Magnetic Observatory, JMA (KAK) as remote reference station. Instead of the conventional Fourier transform, in which temporary transient noises badly degrade the accuracy of long term properties, continuous wavelet transform has been used. The accuracy of the results was as high as that of robust estimations of transfer functions obtained by the Fourier transform method. This would provide us with possibilities for routinely monitoring the transfer functions, without sophisticated statistical procedures, to detect changes in the underground electrical conductivity structure. 相似文献
77.
We investigate linear parabolic systems with coupled nonsmooth capacities and mixed boundary conditions. We prove generalized resolvent estimates in W?1, p spaces. The method is an appropriate modification of a technique introduced by Agmon to obtain Lp estimates for resolvents of elliptic differential operators in the case of smooth boundary conditions. Moreover, we establish an existence and uniqueness result. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
78.
79.
A. Waksberg 《International Journal of Infrared and Millimeter Waves》2002,23(9):1327-1335
Coupling losses have been calculated for laser resonators with unequal apertures and extended Fresnel Numbers. This was done using both, diffraction theory and a simple linear model.A close form expression was derived to calculate coupling losses with reasonable accuracies for a limited range of paramters. This should help in the preliminary design of hole coupling laser resonators. 相似文献
80.
采用基于相对论平均场的耦合常数解析延拓方法研究球形核的单粒子共振态.具体计算了Zr同位素链中巨晕核的核芯核122Zr阈值附近的中子共振态的能量、宽度和波函数,其结果同相应的散射相移法的结果一致. Using analytic continuation in the coupling constant (ACCC) method within the framework of the self-consistent relativistic mean field (RMF) theory, the energies, widths and wave functions for single-particle resonant states close to the continuum threshold are evaluated. Predictions are also compared with corresponding results obtained by the scattering phase shift method. 相似文献