对称

Thirty-one new chiral phosphorus compounds have been synthesized starting from D-camphor,-alpha-phenylethylamine,-Betti base,-1-(4-nitrophenyl)-2-amino- propane-1,3-diol, L-amino acids (such as serine, phenylalanine, proline etc.) and their application as organocatalysts in asymmetric trimethylsilylcyanation of aldehydes and asymmetric borane reduction of prochiral ketones and ketimines were investigated.

该项目从D-樟脑、-alpha-苯乙胺、-Betti碱、-氯酶胺、L-氨基酸（如丝氨酸、苯丙氨酸、脯氨酸等）出发合成了31个新的手性磷化合物，研究了它们作为有机催化剂在醛的不对称硅氰化反应、潜手性酮的不对称硼烷还原反应以及亚胺的不对称硼烷还原反应中的催化效果。

It is revealed that the asymmetric vortices over slender body are formed the breakaways of higher position vortex and generation of new vortex, which are alternately developed on the both sides along the body axis. The correlation between asymmetric vortices structure and distribution of sectional sideforce coefficient has been obtained. A physical model of asymmetric multi-vortices flow structure is developed according to zonal flow analysis.

在此基础上揭示了非对称涡系是通过细长体两侧背涡沿轴向交替脱落、新生而形成的，给出了非对称涡系沿轴向演化、发展的流动结构和截面侧向力分布特性之间的相关关系，在分区分析的基础上提出了非对称涡系结构的物理模型。

So to find a good lower bound is an very important issue in the theory of uniform designs.The present paper aims at obtaining some new lower bounds for the symmetric L_2-discrepancy on some kind of symmetric factorials and asymmetric factorials.

在本文中我们针对某些类型的对称和非对称因子设计得到了对称化L_2—偏差的新的下界，利用这些下界我们不仅可以衡量给定设计的均匀性程度，还可以帮助我们构造均匀设计。

In part two, the empirical results indicate that the predictive ability of SGT is much better than GT、ST、t and Normal distribution. SGT can correct not only fat-tailed property, but also defects the low kurtosis of GT and t distribution. For the volatility of asset return setting, the assumption of volatility of assets price is more appropriate than Normal and asymmetric distribution which was often used.

第二部分以实证结果显示偏态一般化t分配的配适能力较一般化t分配、偏态t分配、对称t分配和常态分配为佳，亦即当金融资产报酬率存在高峰态与厚尾现象时，偏态一般化t分配不仅可以解决常态分配所无法捕捉到的厚尾现象，亦可修正一般化t分配与对称t分配无偏态的缺点，对於资产报酬率波动性之设定，比过去常使用的常态分配与对称的分配更为适当。

The effect of the friction between rolls and ring can be ignored and the effect of the spread velocity of rolling on the deformation of ring is illustrated.

通过模拟分析比较，揭示出了环件轧制过程中的金属流动规律：轧制时，环件外侧的变形最大，厚向中心部位变形最小，内侧的变形程度介于中间；环件内外环面的压应力分布和变化规律：在垂直于环件轴线的对称面上，压应力分布近似对称状态，而且在对称面上的应力最大，往端面方向开始减小；指出了环件轧制中轧辊与环件摩擦对环件成形的影响：对于环件的宽展变形，摩擦的影响很小，可以忽略；分析了环件进给速度对环件成形的影响并阐述了环件厚向中心部位凹陷产生的原因，提出防止凹陷的措施：在轧制时，尽量使用快的进给速度有利于防止端面凹陷的产生；研究了导向辊位置对环件成形以及轧辊受力的影响：导向辊的位置对环件的宽展变形影响很小，但对轧辊的受力影响较大，当导向辊的中心位置位于毛坯初始中心位置之上时，驱动辊和芯辊的受力相对较小，这是导向辊导向时优先考虑的位置。

Its accomplishment is simple and intuitional. The main innovation of this method is that we only need construct a symmetric zonal mesh for each interpolated curve respectively and write appropriate knot spacings for mesh edges. Then applying NURCC rules to the initial control polygonal mesh consisting of those symmetric zonal meshes can generate a surface that satisfies interpolation constrains.

该方法的主要创新思想是在被插值曲线的控制多边形两侧构造具有简单对称性质的四边形网格，称为对称网格带，但关键还在于对网格边赋予适当的节点距，并对由这些对称网格带组成的初始控制网格应用非均匀有理Catmull-Clark细分规则，来生成满足插值要求的曲面。

The knock-down of the three LjCYC genes gives rise to the ventralized identity to all petals, which are keeled shape, resulting in a floral transformation from a zygomorphy to an asymmetry, indicating that the asymmetry floral pattern could be a ground stage before LjCYC1, LjCYC2 and LjCYC3 being recruited in the control of floral asymmetrical development in Lotus japonicus.

本实验得到了LjCYC1、LjCYC2和LjCYC3表达均下调的转基因株系L1+2Ri/kew1，该植株所有花瓣呈现腹部属性，出现了花瓣形态全是龙骨瓣状的非对称花瓣，花型也从两侧对称转化为无对称面；这种花型表明，在LjCYC1、LjCYC2和LjCYC3等三个基因全失活的情况下，龙骨瓣状花瓣应该是一个基准状态。

Two kinds of self-made PCF were used, and an effective fusion scheme was adopted to perform the splicing experiments. By combining experiments and numerical calculations, reasonable fusion parameters were set up and the mode fields at each fiber′s end face were rescaled.

基于一种高效的低损耗熔接方案，将理论计算与实验测量相结合，选取合理的熔接参量对光纤端面模场进行重塑，使两光纤端面模场匹配程度大大提高，从而实现了对称结构与非对称结构PCF之间、以及两种非对称结构PCF之间的低损耗、高强度的熔接。

These classes of the skew-symmetric distributions include the original symmetric distribution and have some properties like the original one and yet is skew.

这类偏斜-对称分布不仅包含原本的对称分布，往往也有一些与原本对称分布相同的性质。

This With the status quo of China's real estate market information asymmetry on the type of real estate information asymmetry, causes, hazards analysis, and how to improve the information asymmetries put forward countermeasures and suggestions.

本文结合我国房地产市场信息不对称现状，对房地产业的信息不对称的类型、成因、危害进行了分析，并对如何改善信息不对称现象提出了对策和建议。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。