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In order to develop an useful synthestic process, we have synthesized amides with various substitutents. The isoquinoline skeleton was constructed through Bischler-Napieralski reaction, followed by asymmetric reduction of the imine intermediates with a Ru complex to form the only chiral center. Finally, we connected the two phenyl groups by Heck reaction and effectively obtained optically active aporphine alkaloids.

为了发展一套实用的合成方法，我们首先制备於苯环上具有不同种取代基的苯乙醯胺，接著透过Bischler-Napieralski反应进行分子内合环，并利用钌金属对亚胺中间体进行不对称的还原反应，建立出产物中唯一的光学活性中心，最后再利用Heck反应连结两个苯环，就可以顺利得到具有光学选择性的阿朴吩类天然物。

They often appear asymmetrically, and many causes result in the asymmetric phenomenon together.

大&和&小常体现出不对称现象，有多种原因共同决定了这些不对称现象。

Numerical calculations show that when azimuthally asymmetric space harmonics increases, the start oscillation length decreases, and that it is possible to increase the start oscillation length by tailoring magnetic field's amplitude and its period.

四、在抑制返波振荡的方法中，改变聚焦磁场是一种比较好的方法，因为改变聚焦磁场几乎不会改变前向波的互作用条件，而会改变返波的互作用条件，因而既可以对返波振荡进行很好的抑制，又有利于提高效率。

The asymmetric distributions of the surface optical second harmonic generation through azimuthally angular scans for thin silver films deposited on Si(111) wafers have been detected with different polarizations of output beams.

实验发现成长於Si(111)基板的银薄膜，以入射基频光、反射二次谐波的不同偏振组合观察到有不对称的方位角二次谐波强度分布之情形。

Experimental results show that in asymmetric flat-flat resonators, when the laser crystal′s position is varied relative to two cavity mirrors, the output power changes in different way, and the radially polarized and azimuthally polarized focal lengths are 31.76 m·W, 42.26 m·W measured respectively.

实验结果表明，在非对称平-平腔中，当激光晶体相对于两面腔镜位置不同时，谐振腔输出功率会出现不同的变化趋势，测量出径向热透镜系数为31.76 m·W和切向热透镜系数为42.26 m·W。

It shows that it is possible to increase the start oscillation length by tailoring magnetic field's amplitude and its period without changing the synchronous condition of the fundamental wave; in the meantime, when there are two or more azimuthally asymmetric space harmonics in the high power broad-band helix TWTtraveling wave tu...

与此同时，对起振长度、初始非同步速度参量随皮尔斯增益参量、空间电荷参量、损耗参量等的变化，以及在超宽带行波管中当存在两个或多个角向非对称空间谐波时，起振长度、初始非同步速度参量随周期永久聚焦磁场的变化进行了研究。优化设计聚焦磁场、电子注和螺旋线慢波系统的参量可以对螺旋线行波管的稳定性分析提供必要的依据。

It shows that it is possible to increase the start oscillation length by tailoring magnetic field's amplitude and its period without changing the synchronous condition of the fundamental wave;in the meantime, when there are two or more azimuthally asymmetric space harmonics in the high power broad-band helix TWT, the influences of the Pierce's gain parameter, space charge parameter, and loss parameter on the start oscillation length and real starting asynchronous velocity parameter are also analyzed.

研究结果表明：改变聚焦磁场的幅值或周期来增加起振长度是可能的，而且不会改变基波的互作用条件。与此同时，对起振长度、初始非同步速度参量随皮尔斯增益参量、空间电荷参量、损耗参量等的变化，以及在超宽带行波管中当存在两个或多个角向非对称空间谐波时，起振长度、初始非同步速度参量随周期永久聚焦磁场的变化进行了研究。

In the dissertation, we presented a method to calculate the start oscillation length and real starting asynchronous velocity parameter. In the meantime, when the effect of two or more azimuthally asymmetric space harmonics in the high power broadband helix TWT on the start oscillation length and real starting asynchronous velocity parameter were also analyzed.

数值计算表明：增大渐变的强度，就可以增加起振长度，而且当渐变的强度增大到一定值时就不会产生返波振荡；当衰减器靠近输入段时，起振长度就随之减小；当增大衰减器的长度或减小衰减量时，相对起振电流随之减小，可见衰减器对起振条件确实有明显的影响。

Leaves abaxially barbate at vein axils, leaf bases asymmetric.

Culm 芽不具粉霜，无毛；披针形的叶片，1.5-2.6厘米宽，干燥时通常平 4 S。

Chiral N, P bidentate ligands, were used for the first time in Ag -catalyzed asymmetric addition of allyltributyltin to benzaldehyde.

在此催化体系中，MAP系列氮膦配体的不对称诱导性能明显好于H〓-MAP系列的氮膦配体。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失