不对称

The asymmetric addition of terminal alkynes to aldehydes and ketones is an important method of synthesizing chiral propartyl alcohols and tertiary alcohols, which are important pharmaceutical intermediates.

末端炔对醛和酮的不对称加成是合成光学纯的炔丙醇和手性叔醇的重要方法，是不对称催化的重要研究课题之一。

All the prepared compounds were characterized by 〓H NMR、〓P NMR and elemental analysis. The catalytic activity of each prepared chiral phosphorus compound in the borane reduction of prochiral ketones was studied.

对每一种手性磷化合物，考察了其作为配体催化剂在潜手性酮的不对称硼烷还原反应中的催化效果，讨论了影响不对称诱导的各种因素。

Finally, analyse the calculated results of this ship with another catamarans. From this result obtained unsymmetrical catamaran hull of this particular special vibration mode and analyse the vibration mode in order. The calculation is fairly reasonable, for the future of the asymmetric catamarans to calculate the vibration analysis of a number of reference.

最后将本船计算结果与另一艘双体船计算结果进行了比较分析，得到不对称双体船这种特殊船型的特殊振动模态，并就其振动模态出现次序进行了比较分析，说明本次计算是比较合理的，为今后不对称双体船的振动特性分析计算提供了一些的参考。

In view of the development about the certain airborne radar antenna array,considering the structural features of antenna array,analyse the cruces in manufacturing of feed cavity and radiant plate,and present the corresponding solution by mainly dealing with precise positioning style,delicate clamp design,error distribution and compensation method,high speed machining technology design,machining simulation and program optimizing.

某机载雷达平面裂缝阵列天线的单面阵如图1所示。该面阵布置多路裂缝线源，共分布384处长度各不相同的辐射裂缝，每一路线源均由脊型波导口单独馈电。面阵由辐射板和馈电腔两个零件组成，采用整体钎焊成形。线源结构为非对称单脊共线形式，即在普通单脊波导的两侧与辐射裂缝相对应的位置上布置不对称的凹台。

In order to solve the problems of bad shunting and red light strip phenomenon at electric railway section caused by the defective of asymmetric pulse track circuit receiver formerly, a new type of asymmetric impulse track circuit receiver is designed. It takes the PIC16F887 single-chip microcomputer as central processing unit of the system, realizes processing and judging the asymmetric impulse from the track transformer automatically. The article focused on the receiver work flow, hardware circuit and software design.

摘 要：为了解决以往多数不对称脉冲轨道电路接收器存在缺陷而导致的分路不良问题和电气化区段空闲&红光带&现象，设计了一种新型脉冲轨道电路接收器，系统以PIC16F887单片机为核心处理单元，自动实现对由轨道变压器传来的不对称脉冲信号进行处理和判决，重点讨论了接收器工作流程、硬件电路实现以及软件设计。

Considering the prerequisite of joint non-linearity and glue-line elasto-plasticity,the stress distributions in the glue-line of asymmetrical joint for continuous or gap jointing were analyzed by finite element method and glue-line structure optimization was made.

在考虑接头非线性和胶层弹塑性的前提下，利用有限元方法分析了连续胶层不对称接头和间隙连接不对称接头中胶层内的应力分布情况，并在此基础上对胶层结构进行优化。

In this dissertation, the efforts were focused on asymmetric cyanation of acitive ketones and asymmetric Henry reaction.

本文致力于催化羰基化合物的不对称腈化反应和不对称Henry反应研究，取得了一些具有重要学术意义和应用前景的创新性结果。

The normal mamillothalamic tracts and mamillary bodies were symmetric in size and signal intensity. The abnormal mamillary bodies were identified as asymmetric in size.

正常乳头丘脑束及乳头体两侧对称，信号均匀，与穹窿的信号一致；异常的乳头体表现为两侧不对称，一侧明显变小，并且乳头丘脑束显示不清。

Metrical verse emphasizes symmetry and uniformity. My own impulses are toward asymmetry and syncopation: the off-balance, the slant, the microtonal, but still with a pulse.

格律诗强调对称与统一，而我则倾向于不对称和切分法：即不平衡、倾斜、微音程，但仍然具有律动。

The frequency and amplitude of wake force were deduced theoretically, while the influence of stator sector distribution and stator vane quantity on the wake force of vane was also discussed. Transient analysis was conducted for the forcing response of rotor blades under the same stator sector distribution and different quantities of stator vane, so an optimum asymmetry stator mistuned design was developed.

对不对称静子叶片非谐情况下激振力频率幅值进行推导，讨论了静子扇区分布和静叶数目选取对尾流激振力的影响，并对相同扇区分布不同静叶数目情况下转子叶片的强迫响应进行瞬态分析，给出不对称静子非谐设计的最优方案。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。