原子键

The results show that the major contribution to DOS of Mg and Pb are the 2p orbit of Mg and the 5d orbit of Pb, followed by the 3s orbit of Mg and the 6p orbit of Pb, the 6s orbit of Pb is the smallest one. There are a large number of charges around Mg, it has the characteristics of typical metal bond. Mg and Pb share some charges to form covalent bond, but the distortion of the charge at the junction is little; the proportion of covalent bond is less than the metal bond, Mg2Pb is semimetal. The elastic modulus and shear modulus of Mg2Pb are 68.6 and 27.9 GPa, respectively. Based on Pugh empirical criterions and Poisson's ratio, Mg2Pb is brittle in nature.

结果表明：Mg和Pb对态密度的贡献主要是Mg的2p轨道和Pb的5d轨道，其次为Mg的3s轨道和Pb的6p轨道，Pb的6s轨道贡献最小；在Mg原子周围有大量的电荷存在，呈典型的金属键特征，Mg、Pb之间存在共用的电荷，有较强的离域性，以共价键形式存在，但交界电荷的畸变不大，故共价键所占比例较少，金属键所占比例较大，Mg2Pb化合物呈半金属性；Mg2Pb的弹性模量和切变模量分别为68.6和27.9 GPa，Pugh经验判据和泊松比均表明Mg2Pb具有脆性。

A positively-charged chemical species where the positive charge is localised on a carbon atom. Both carbenium ions (which have three bonds to a positively charged carbon) and carbonium ions (which may have five or more bonds to a positively charged carbon) are examples of carbocations.

碳阳离子：正电荷位于碳原子上的一种正电性的化学物种，碳正离子（三个键连接在带正电的碳上）和碳鎓离子（有五个甚至更多的键连接在正电性的碳上）都属于碳阳离子。

They suggested that radicals with a double bond 13 to the carbon bearing the peroxy groups (which can only arise from acids containing more than two double bonds) cyclize to form peroxides with five-membered rings.

他们认为连接过氧基的碳原子有一个双键的游离基(只有多于两个双键的酸可形成)环化形成五元环的过氧化物。

In the thesis, we wish to report the synthesis and structures of a series of new type rigid conjugated nanometer-sized fulvene ligands, and coordination polymeric compounds based on both metal-carbon and metal-heteroatom interactions and also H-bonded supramolecular architectures generated from this new type of fulvene ligands.

基于此，我们合成了一系列刚性共轭的纳米级富烯类配体，并以之与过渡金属离子反应合成了同时基于金属-碳和金属-杂原子两种键合作用的有机-无机配位高聚物及以氢键作用为驱动力的超分子聚集体。

Only when the outer electrons forming dangling bonds absorb noncontiguous specific energy and transit into relative free status, can they bond with each other, that is, only when C atom in 3DB status takes in enough energy and conquers potential barrier can it realize reconstruction.

构成悬挂键的外层电子只有吸收非连续的特定能量跃迁成相对自由状态才可能彼此成键，即处于3DB状态的C原子吸收足够能量克服势垒才能实现重构。

Through cyclic hydrogen bonding with motif formed by coordinated water molecules and coordinated hydroxyl groups of dhbd from adjacent tetranuclear units, these adjacent neighbors are connected to afford a 1D supramolecular chain along axis a, which is further extended via aromatic intercalations and other crystallization water molecules into a 3D structure with channels.

毗邻的四核单元通过配位H2O分子和配位羟基O原子形成的 R 22(8)型环形氢键桥的连接，沿a轴方向构建了四核单元交替相连的一维超分子链；链间籍苯环的π-π堆积作用和晶格水分子氢键链的连接进一步扩展为具有隧道的三维结构。

Comparisons show that there is no correlation between the experimental sensitivity of tetrazole compounds and various previously proposed theoretical static criteria, such as the bond length and bond order of relevant bonds, net atomic charges and electronegativity and the content of 2H-teterazole isomers in both gaseous and condensed states.

把四唑衍生物的实验感度与前人曾提出过的各种感度理论判据—一些静态结构性质(如相关键的键长、键级、原子电荷和电负性等)以及平衡体系中2H-异构体的含量—进行比较，均未找到它们之间的规律性联系。

A computer simulation tracking study for the rapid solidification proc esses of liquid metal Ga system has been performed by using molecular dynamics method.

采用分子动力学方法对液态金属Ga的快速凝固过程进行计算机模拟跟踪研究，运用HA键型指数法和原子团类型指数法分析了金属原子Ga的成键类型和形成的基本原子团结构。

The force is dominated by entropy force when the chain isdeformed less than 0.9 of the full-extended chain, while by enthalpy force. Theenthalpy force is contributed by the intro-molecular interaction. Bond stretchcontributes to the force more than bond angle bend. Torsion and VDW contributelittle to the force.3. The internal energy contribution to the elastic force It is in dispute that whether 〓 is dependent on the strain, and it is hard toresolve the problem using present elastic theories because they are athermal.

我们模拟了聚乙烯模型聚合物的SMFS，研究了链长、势能有效距离和温度对力谱的影响，探讨了力谱的本质问题，得到以下结果：改进的分子动力学方法可以很好的模拟聚合物的SMFS；SMFS是链段的性质而不是整个高分子链的性质，对于聚乙烯，该链段碳原子数目大于40；SMFS的本质是熵弹性，形变小于全伸直链的0.9时，力为熵弹力；形变超过全伸直链的0.9时，能弹力占主导地位，这种能弹力完全是分子内相互作用引起的，是由键伸缩和键角弯曲贡献的。3。

Cytosine and nitrogen monoxide have been made Both N and O can combine with N--H bonds of cytosine and then hydrogen bonds between them are formed.

其结合方式是NO的N或O原子与胞嘧啶的N—H键形成氢键，最稳定的复合物的结合能为-9.65kJ／mol。

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。