对称

A novel structure of Yan-13 molecule was determined by X-ray single crystal diffraction analysis.

从表面上看起来Yan-13分子是中心对称的，事实上，它是不对称的。

Having as many planes as required for complete symmetry in a given crystal system.

全面的，全对称晶形的具有在给定的晶体系统中全面对称的全部平面的

The metazoans in the Wenghui Biota had radiate symmetrical animals, including Porifera, Ctenophora, Cnidaria, and Trilobozoas, and bilateral symmetrical animals, including Annelida and possible Mollusca.

瓮会生物中宏体后生动物有海绵类、栉水母类、刺胞类和三叶类等两胚层辐射对称动物以及环节类和可能的软体类等三胚层两侧对称动物。

Six days after inoculation, the cucumber root tip was slightly swollen and symmetrical root-knots were observed at the meristematic and elongation zones. Giant cells were differentiated by previous cambium cells in the center of the root; 10days after inoculation, symmetrical and secondary root-knots were observed at the root hair and upper zones. Vessels were separated by giant cells, around which protoxylem vessels were observed; l6days after inoculation, hypo-vascular tissue appeared earlier than normal; 20-30 days after inoculation, the vertical arrangement of vessels was disordered, shape was distorted and a new vascular tissue appeared in the cortex.

结果显示：接种后6 d的根尖分生区、伸长区出现膨大、对称的根结，根中心的原形成层细胞分化出巨型细胞；10 d在根毛区及以上部位出现既有对称又有偏于一侧的根结，周围有原生木质部导管出现，根结中巨型细胞阻断了导管；16 d次生维管组织提早出现；20~30 d导管纵向排列无序，形状扭曲，皮层中有新维管组织产生。

Principal curvatures and principal directions are obtained by computing in closed form the eigenvalues and eigenvectors of certain 3×3 symmetric matrices defined by integral formulas, and closely related to the matrix representation of the tensor of curvature.

通过计算3×3对称矩阵的特征值和特征向量可以得出主曲率和主方向，而该对称矩阵是由积分公式定义并且与曲率张量的矩阵表达密切相关。

The cyclic symmetry algorithm can greatly save the computer memory and the CPU time without inducing any additional approximation. At last, the programs including pre-processing, calculation and post-processing are developed based on the models and methods mentioned above.

最后，在以上理论分析的基础上，本文编制了适用于循环对称结构的静应力与振动特性分析程序，以及适用于该程序的前后处理接口程序，并进行了算例验证，证明由循环对称算法得到的结果与整体算法、实验得到的结果完好吻合。

The method may be applied to cylindrically or spherically symmetric and optically thin ...

可以把这种方法应用到在等离子体物理和天体物理中经常遇到的柱对称或球对称的光学薄的等离子体上。

I find that:(1) consistent to the prediction of information asymmetry model,the degree of information asymmetry and ex ante uncertainty is a decreasing function of profitability and offering size.

研究发现：(1)与信息不对称假说一致，盈利能力和发行规模可以降低信息不对称的程度与事前不确定性，与IPO折价率有显著负相关关系。

These dendritic NOBIN derived Schiff base ligands have been applied to titanium catalyzed hetero-Diels-Alder reaction of Danishefshy's diene and aldehydes, affording the corresponding 2-substituted 2, 3-dihydro-4H-pyran-4-one in quantitative yields and excellent enantioselectivities (up to 97. 2%ee). Comparing the reactivities and enantioselectivities of reaction catalyzed by the titanium complexes of these Schiff base ligands, it was found that a series of ligands L〓 were superior to the other three series of ligands L〓, L〓 and L〓, a significant positive NLE and a dendrimer effect existed in the L〓 dendritic catalyst system. The disposition of the dendritic wedges and the dendron size in the ligands were observed to have a significant impact on the enantioselectivity of the reaction.

NOBIN衍生的树枝状大分子希夫碱手性配体与钛形成的配合物在催化不对称杂Diels-Alder反应中的应用将得到的四个系列NOBIN衍生的树枝状希夫碱三齿手性配体与四异丙氧基钛形成的配合物用于催化Danishefsky's diene与醛的不对称杂Diels-Alder反应，通过反应条件的优化，获得了定量的收率和最高达97.2％ee值的对映选择性；考察了这四个系列NOBIN衍生的树枝状希夫碱钛配合物的催化活性和对映选择性，结果发现它们的活性次序依次为L〓≈L〓＞L〓＞L〓，对映选择性次序依次为L〓＞L〓＞L〓＞L〓。

The paper has discussed such problims as the properties of sub-eigenvalue and sub-eigenvector of real-anti-sub-symmetric matrix,and its diagonalization.

讨论了实反次对称矩阵的次特征值与次特征向量的性质及实反次对称矩阵的对角化问题。

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。