对称

The third part of this thesis is reactive simulating calculation In this section, some well-known auxiliaries are selected to compute in density functional theory B3LYP on Gaussian 03, from which the relationship between reaction active energies of transition states and enantiomeric excess of chiral products homoallylic alcohols isobtained based on relative reactive ratio theory. Using this relationship, calculations on the reaction of more than eight auxiliaries with four other aldehydes are carried out in AMI and MNDO, proving that N,N\'-dibenzyl tartamide has higher enantioselectivity than others in this reaction.

第三部分为计算化学部分，运用密度泛函理论B3LYP方法在Gaussian03软件上对已经报道的几种手性配体参与的醛不对称烯丙基化反应过程进行模拟计算，基于相对反应速率理论找出两种构型过渡态间活化能的差异与产物光学收率之间的关系；并以此为基础，用AM1和MNDO方法对上述合成的几种配体控制的反应过程进行量化计算，从而在理论上证实了N-苄基酒石酸二酰胺配体在醛的不对称烯丙基化反应中具有较高的立体选择性。

The first asymmetric synthesis of trans-β-hydroxy-γ-butyrolactones:-(3R, 4R, 5S)-4-(1-acetoxy-isopropyl)-3-hydroxy-butyrolactone 65a was achieved starting from isobutylaldehyde through nine steps. The key steps involve the construction of three chiral carbon centers by the Sharpless's asymmetric epoxidation and Substrate directable chemical reaction.

以异丁醛为起始原料，经过九步反应首次设计合成了具有三个手性中心的trans-β-羟基-γ-丁内酯：-（3R，4〓，5S）-4-（1-乙酰氧基-异丙基）-3-羟基-丁内酯65a，关键步骤是Sharpless不对称环氧化和底物定向不对称合成反应。

However, Japanese designers are more prefer to symmetric distribution rather than the dissymmetric pattern of the European constructivism, as the core symmetry is one of the components of the Japanese traditional designing. Consequently, they modulated the European constructivism by adding some of the simplified symbolic patterns, which are parts of the traditional designing, i.e. patterns of grass, animals and floras etc. into the Japanese constructive designing.

但是， 日本设计家更加喜欢对称化的布局，而不是构成主义非对称化的方式，中轴对称是日本长期的传统设计的组成部分之一，因此日本的设计对欧洲的构成主义进行了调整，把传统设计中一些简单化的象征性图案，比如花草、动物、植物纹样等等，都加入到日本式的构成主义设计中。

Under the affecting of longitudinal and latitudinal wind stress together, longitudinal wind stress of zero class that is symmetrical to equator has no effects on equations. Nevertheless, longitudinal wind stress of one class that is dissymmetric to equator changes the result and makes longitudinal flow not equal to zero.

在经向风应力和纬向风应力的联合驱动下海洋会有不同的响应，零阶的经向风应力也即对赤道对称的经向风应力没有影响到最后结果，而只有一阶的经向风应力也即对赤道反对称的经向风应力，或者说具有辐合辐散的经向风应力对最后的速度场和位势场造成影响，而且一阶经向速度也不再为零。

As to the CVC hot strip mills which spread to the world soon after its boom in the 1980s, this paper analyzes its dissymmetric CVC roll surface curves, and builds dissymmetric rolls elastic deforming model and crown and shape calculation model of CVC hot strip mills.

对八十年代兴起并得到迅速推广的CVC热带钢连轧机，本文对其非对称CVC辊型特点进行了分析，建立了非对称问题的辊系弹性变形模型，并研究了CVC热连轧机板凸度和板形计算模型。

There exists the principal-agent relationship between stockholders and managers,which takes on different patterns under different conditions:under the condition of symmetric information,it displays as order-subordinate rela- tion ship,which need not incite managers while stockholders can pay managers regular fee by contract;under the con- dition of dissymmetric information,it displays as a fellowship,which need incite managers because managers may per- form according to the payment.

股东和经营管理者之间存在委托代理关系，这种委托代理关系在不同情况下具有不同的表现形式：在信息对称条件下，表现为命令和服从关系，此时无需对经营管理者进行激励，股东以&强制合同&的形式支付给经营管理者确定的报酬即可；在信息非对称条件下，委托代理关系表现为合伙关系，对经营管理者的激励相当重要，因为经营管理者会根据激励强度来付出劳动。

Classified by commodity variety, it can be categorized into the counterfeiting of consuming goods, agricultural goods, architectural materials, medical goods, industrial means of production, publication, paper currency and cultural relics; classified by nature, it can be categorized into fake commodities and substandard commodities; classified by information structure, it can be categorized into the counterfeiting of symmetric information and dissymmetric information.

按照商品品种分类，可以分为消费品类假冒伪劣、农资类假冒伪劣、建筑类假冒伪劣、药品类假冒伪劣、工业生产资料类假冒伪劣、出版类假冒伪劣和纸币文物类假冒伪劣；按照性质分类，可以分为假冒商品、伪劣商品；按照信息结构分类，可以分为不对称信息的假冒伪劣、对称信息的假冒伪劣。

There is a saying in China: The sellers are always more clever than the buyers. This saying indicates the connotation of dissymmetrical information in economics and catholicity of dissymmetrical information in reality.

&买的不如卖的精&，中国的这一俗语形象地点出了经济学的非对称信息理论的内涵和现实中非对称信息的普遍性。

The principle of harmonic wave detection which is based on wavelet transform was expatiated. It introduced a new approach of harmonic measurement based on period-interleaving of arithmetic for dissymmetrical system.

首先论述了基于小波变换的谐波检测的原理，根据目前小波变换在三相不对称系统谐波检测中存在的无法分离基波信号之不足，介绍了一种用于三相不对称系统的基于周期交错的测量方法。

The paper analyses the cooling process of symmetrical and dissymmetrical section profile with FEM software ANSYS, then adopt the data to guide the design of moulds cooling system.

使用有限元分析软件ANSYS分析了对称截面和不对称截面两种型材在定型模内冷却的过程，并采用分析得出的数据指导定型模冷却系统的设计。

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％。