原子键

The theoretical system for describing the structures of organic and drug molecules using 3 types of molecular electronegativity-distance is created based on various atomic types and atomic attributes. These MEDVs include MEDV-4 based on 4 atomic types and relative electronegativity and relative bond length to carbon atom, and molecular holographic distance vector based on 13 atomic types and relative bond length to carbon atom, and MEDV-13 based on 13 atomic types and atomic attributes and the modified electrotopological state index.

通过不同原子类型与原子属性划分方案，创建了3种形式的分子电性距离矢量即以4种原子类型划分方案和以碳原子为标准的相对电负性与相对键长为基础的分子电性距离矢量MEDV-4、以13种原子类型划分方案和相对键长为基础的全息分子距离矢量MHDV、以13种原子类型与43种原子属性划分方案以及修饰的电拓扑状态指数和拓扑距离为基础的分子电性距离矢量MEDV-13等3种矢量描述子表征分子结构的理论体系。

On the electronegative elements, bonding electron number and bonded hydrogen atomic number, new molecular topological index is developed to do research on creaturely activity for alcohol, aether, ketone and ester in this paper.

基于元素的Pauling电负性，原子成σ键的电子数，原子直接键连的成σ键的氢原子数目和原子在形成离域π键时所提供的P电子数，定义了一种原子点价公式，构建了分子连接性指数。

By introducing the concepts of atomic type and atomic attribute, MEDV was applicable to various molecular structures which contain the multiple bonds and heteroatom.

通过引入原子属性和原子类型的概念构建的MEDV，适用于描述含多个杂原子、饱和键与不饱和键、环和非环等分子结构特征。

In addition, the changes of molecular geometry, atomic natural charge and IR spectra of the reaction system during the crucial step of O to attack H showed that the rupture of C—H bond and the formation of O—H bond were concerted stepwise. Obvious changes of atomic natural charge happened to atoms C(1), H(11), O(28), O(29) and N(27). The bond lengths and bond angles related to these atoms were also varied greatly.

NO2中O进攻1-H决速反应过程中，分子几何、原子自然电荷及IR光谱变化表明， C—H键的断裂和N—H键的形成是一个协同过程；参与新键形成和旧键断裂原子C(1)， H(11)， O(28)， O(29)和N(27)的原子自然电荷及与其相关的键长、键角有明显的变化。

The Mo center of [Mo8](superscript 4)-shows a slight distorted square antiprism coordination environment. The N atoms of cyano groups, acting as acceptors of hydrogen bonds, together with protonate N atoms from organocations and the lattice water, serving as donors of hydrogen bonds, form intricate hydrogen bond interactions, thus generating three-dimensional supramolecular network with the help of π-π interactions of some organocations.

Mo8(上标 4-)离子中，Mo中心处于扭曲的反四棱柱配位环境。8个未配位的氰基氮原子作为氢键的受体，有机阳离子上质子化的氮原子和结晶水作为氢键的给体，形成了丰富的氢键作用，这些氢键作用连同部分有机阳离子间的π-π堆积、阴阳离子间的静电力和Van Der Waals力构筑成三维超分子网络。

Similar to the oxidation process of Si(111)-7×7 by water,the gradual insertion of S atom into Si_a-Si_s backbond is possible to occur,and the insertion pathway,which begins with directly destroying Si_a-Si_s backbonds by a foreign H_2S molecule,remains more favorable.However,when H_2S attacks at the Si_a site to split Si_a-Si_s backbond with its S or H atom,there is no distinct thermodynamical and kinetical difference between these two attacking behaviors,whereas Si_a-Si_s backbond is easilier broken when H_2O attacks at the Si_a site with its O atom.This mainly lies in the fact that the electronegativity of oxygen is larger than that of sulfur.

5类似于H_2O对Si(111)-7×7的氧化历程，S原子逐步插入Si_a-Si_s键是可以发生的，且H_2S直接打开Si_a-Si_s键进而使S原子插入的途径仍是动力学上较为有利的，但H_2S以S或H原子进攻Si_a位从而打开Si_a-Si_s键的两种反应机制在动力学和热力学上并没有表现出明显的差别，而当H_2O以O原子进攻Si_a位时，Si_a-Si_s键则较容易断裂，这应归因于O的电负性比S大。

The structure analysis indicates that the reverse symmetry ligand H4LB molecules are linked into a 2D supermolecular network by two types of hydrogen bonds. One type occurs between the oxalamide oxygen group and the phenol hydroxyl qroup of the nearest molecule with d=2.906(2) and ∠O-H…O=151.8°. The other type is between the oxalamide nitrogen group and the oxalamide oxygen group of anther molecule with d=2.849(2),∠N-H…O=158.7°.

晶体结构研究表明配体H4L为顺式桥联分子，晶体中存在两种氢键，一种是草酰胺基团的O原子与苯环上的酚羟基形成O-H…O氢键[d=2.906(2)，∠O-H…O=151.8°]；另一种是草酰胺基团的氨基与相邻草酰胺基上的O原子形成N-H…O氢键[d=2.849(2)，∠N-H…O=158.7°]，通过上述两种氢键将化合物H4LB连接成二维网络结构。

the title compound was synthesized and its structure was studied in theory.the schiff base compound was synthesized by condensation of paeonol with furylfurylamine,then it was deoxidized by sodium borohydried.the energies,bound lengths,bound angles,the net charges of main atom and contributive percents of frontier orbital in the title compound have been calculated by software hyperchem 7.0 in half experience method.the yield rate of title compound was 65.6%.the result of calculation showed that the most of the bond lengths and angles in the system were in the the normal range,negative charge mainly concentrate on o1,o2,o3 and n1.the title compound behaves as quadridentate ligand.

目的合成标题化合物并对其结构进行了理论研究。方法以丹皮酚和糠胺为原料合成席夫碱，经硼氢化钠还原得标题化合物；使用hyperchem7.0程序，用半经验方法计算了化合物分子中能量分布、主要键长、键角以及主要原子的净电荷分布和前言轨道分布。结果标题化合物，收率65.6%；计算结果分析表明，分子中主要原子之间的键长、键角基本在正常的范围内；负电荷主要集中于o1，o2，o3和n1上。

The analyses of electronic structures shows that the catalytic reactivities for H2 adsorption of the different surfaces are dependent on the numbers of s orbital bonding electrons around Fermi level for the uppermost layer metal atoms which interact directly with H2. It is easy to form vacancy for hydrogen atoms next to iron atom, which indicates that hydrogen atom cannot be escaped, but it is difficult to from vacancy for hydrogen atoms next to magnesium atom, which indicates that hydrogen atom can be escaped. Hence it is thought that the change of dehydrogenating properties of MgH2 with or without a little iron addition attributes to the weakened bonding between magnesium and hydrogen.

分析电子结构发现：空位缺陷有助H2吸附于Mg表面，与Mg(0001)表面最上层与H2直接产生吸附作用的金属原子在费米能级附近s轨道的成键电子数密切相关；在Fe合金化MgH2体系中，与合金化元素Fe近邻的H原子形成空位的难度增加，H原子较难释放；与Mg近邻的H原子形成空位的难度减少，H原子容易释放；Fe合金化导致Mg-H之间存在较弱的成键作用，因此，MgH2体系的解氢性能得到提高。

The calculated results show that azido in azides has linear structure , the most optimized CaN6 has linear structure , and the most optimized (CaN6)n (n=2～5) clusters have chain structure of perpendicularity of approximate diamond composed by two azido with two Ca atoms . The middle N atoms of azido show positive, the N atoms at both ends of azido show negative, and the N atoms effected with Ca atoms directly show more negative . There is strong ionic bond between the Ca and N atoms. The IR spectra of the most optimized (CaN6)n (n=1～5) clusters have four vibrational sections , the whole strongest vibrational peak lies in 2195～2280cm-1,and the vibrational mode is anti-symmetric stretching vibration of N-N bonds in azido . Stability analysis show that (CaN6)3 and (CaN6)5 clusters are more stable than other clusters .

结果表明，叠氮化合物中叠氮基以直线型存在，CaN6团簇的最稳定结构为线型结构，(CaN6)n(n=2～5)团簇首先由两个叠氮基与两个Ca原子构成一个近似菱形，再由菱形相互垂直形成链状最稳定结构；叠氮基中间的N原子显示正电性，两端的N原子显示负电性，且与Ca直接作用的N原子负电性更强，金属Ca原子和N原子之间形成很强的离子键；(CaN6)n(n=1～5)团簇最稳定结构的IR光谱分为4个部分，其最强振动峰均位于2195～2280cm-1，振动模式为叠氮基中N-N键的反对称伸缩振动；稳定性分析显示，(CaN6)3和(CaN6)5团簇相对于其他团簇较为稳定。

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。