对称中心

A center of symmetry must coincide with the center of mass.

对称中心必须与质量中心重合。

This article according to the function image axial symmetry and the point symmetry basic principle,the use function taylor series expansion,determines and seeks the polynomial function image the axis of symmetry or the center of symmetry.

根据函数图象轴对称及点对称的基本原理，利用函数的泰勒级数展开式，来判定和寻找函数图象的对称轴或对称中心。

At the central frequency of the reduced units 0.5(ωa/2πc), when the transmission band of photonic crystaln is completely inside the band gap of photonic crystalmm, both sharing the same central frequency as their symmetry centers, mirror symmetrical photonic quantum well is formed.

针对光子晶体mnm模型，选择适当的结构参数，通过传输矩阵法对其透射谱进行计算模拟发现，在归一化中心频率0.5(ωa/2πc)处，当光子晶体n的导带处于光子晶体mm的禁带中，且两者均以中心频率处为对称中心时，构成镜像对称的光子晶体量子阱结构。

Configurational isomerism is then due to the presence in the molecule of one or more dissymmetric centres ,in the simplest case asymmetric carbon atoms ,each of which can have and absolute configuration; and ,or ,to the presence of double blonds which can give cis- and trans-geometrical isomers .

构型异构是由于分子中存在一个或一个以上的不对称中心，在最简单的情况下是不对称碳原子，每个不对称碳原子的绝对构型是和；或者，如果存在双键的话，那么将给出顺式和反式几何异构体。

The central atom is bridged to each ofthe two external copper atoms through triple triazole ligands.

在5的配阳离子中，中心铜离子处在反对称中心与六个admtrz桥的六个氮原子形成拉长的八面体配位环境。

Ourgoals are to synthesize new triboluminescent complexes, to determine their crystalstructures, photoluminescence spectra and triboluminescence spectra, and to dosystematic researches of relationships between their crystal structures andtriboluminescent activities.

为了解释有对称中心结构的物质具有摩擦发光现象，Sweeting提出，在具有摩擦发光特性的有对称中心结构的物质中，少量的杂质及结构的无序可能对摩擦发光起了很重要的作用。

The structure consists ofpolyborate groups 〓 and four crystallographically independent Y positions, ofwhich two positions are on inversion center and the other two are on general positions.

中的硼酸根离子为三个四面体构成的〓基团，结构中存在有四种不同的Y原子格位，其中两种Y格位具有中心对称，另外两种Y格位没有对称中心。

Crystal structural analysis reveals that, because water molecules bond to Cu atoms, the dhbd ligand can only adopt a hydroxyl oxygen atom to bridge two reversed U-shaped subunits into a novel centrosymmetric dual-U-shaped tetranuclear Cu structure. Each U-shaped frame consists of two crystallographically distinct Cu atoms, two dpphen ligands and one coordinated water molecule.

晶体结构分析表明，由于水的配位阻断， 2，3-二羟基丁二酸根仅通过单羟基氧桥联两个U形双核亚单元形成具有一个对称中心的双U形四核结构，其中U型亚单元包含晶体学上不对称的2个Cu原子、1个2，3-二羟基丁二酸根、2个4，7-二苯基-1，10-邻菲咯啉和1个配位H2O分子。

It was found that the central metal ion is located at the symmetric center of the molecule. Four oxygen atoms from two H2O molecules and two 〔C6H4(CO2)2〕2- groups are coordinated with copper ion to form a similar planar square coordination configuration. There is one only unidentate coordination bond between O(1) in 〔C6H4(CO2)2〕2- and Cu2+.

结构分析发现，中心金属离子位于分子的对称中心位置，铜离子与来自2个水分子和2个邻苯二甲酸根中的4个氧原子形成近似正方形平面配位，邻苯二甲酸根是以1个O(1)与Cu2+离子形成单齿配体，O(2)和Cu2+之间没有形成配位键。

In the high accuracy diffraction measurement of laser for a tiny wire,polarization direction of laser,laser beam property,and deviation of the beam center from the wire center have an effect on the measuring result.

在丝径的激光高精度衍射测量中，激光的偏振方向、光束的几何属性和光束中心对衍射体对称中心的偏离都会影响测量的结果。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。