原子键

The results show: the strongest bond is the Al-Al bond in the segregated cell without containing vacancy, where the Al atomic covalence radius is greater than that of Li atom in the cell; while the strongest bond is the Al-Li bond in the segregated cell containing vacancy, and the Al atomic covalence radius in the cell is less than that of Li atom. Since the difference of electronagativity between the Al and Li atoms is obvious, it is inclined to formed the Al-Li segregated cell of short range order structure in the condition of vacancy present. The short range order structure containing vacancy is probably the embryo or precursor structure of the metastable phase δ′(Al3Li). Because the strongest covalent bond in the Al-Li-vacancy segregated cell in alloy formed in quenching is the main strength reason for supersaturated solid solution of alloy. The bond net of succeeding precipitation of δ′(Al3Li) has the picture of anisotropic Al-Al bonding and the bond intensity enhanced. Since the δ′(Al3Li) is coherence with matrix, the bond net strength is enhanced by the precipitation of δ′(Al3Li) and so strengthen the alloy.

计算结果表明：不包含空位的偏聚晶胞的键络最强键为Al—Al键，其中Al原子的共价半径较Li原子的共价半径要大；而含空位的偏聚晶胞的最强键为Al—Li键， Al原子的共价半径要比Li原子的共价半径要小；在空位存在的情况下，由于Al原子与Li原子的电负性相差明显，促使Al和Li原子结合，倾向形成Al-Li短程序结构偏聚区，这种含空位的短程序结构很可能就是δ′(Al3Li)亚稳相的前兆结构和生长胚胎；由于Al-Li-空位有序偏聚晶胞的Al—Li键络比基体键络要强许多，因此，淬火过程中合金生成的Al-Li-空位偏聚晶胞对合金过饱和固溶体起主要强化作用；后续析出的δ′(Al3Li)亚稳相键络各项异性显著，键络强度明显提高；由于Al3Li与基体共格，其大量均匀弥散析出起到提升基体整体键络强度，同样对合金产生强化作用。

The results show: the strongest bond is the Al-Al bond in the segregated cell without containing vacancy, where the Al atomic covalence radius is greater than that of Li atom in the cell; while the strongest bond is the Al-Li bond in the segregated cell containing vacancy, and the Al atomic covalence radius in the cell is less than that of Li atom. Since the difference of electronagativity between the Al and Li atoms is obvious, it is inclined to formed the Al-Li segregated cell of short range order structure in the condition of vacancy present. The short range order structure containing vacancy is probably the embryo or precursor structure of the metastable phase δ'(Al3Li). Because the strongest covalent bond in the Al-Li-vacancy segregated cell in alloy formed in quenching is the main strength reason for supersaturated solid solution of alloy. The bond net of succeeding precipitation of δ'(Al3Li) has the picture of anisotropic Al-Al bonding and the bond intensity enhanced. Since the δ'(Al3Li) is coherence with matrix, the bond net strength is enhanced by the precipitation of δ'(Al3Li) and so strengthen the alloy.

计算结果表明：不包含空位的偏聚晶胞的键络最强键为Al-Al键，其中Al原子的共价半径较Li原子的共价半径要大；而含空位的偏聚晶胞的最强键为Al-Li键，Al原子的共价半径要比Li原子的共价半径要小；在空位存在的情况下，由於Al原子与Li原子的电负性相差明显，促使Al和Li原子结合，倾向形成Al-Li短程序结构偏聚区，这种含空位的短程序结构很可能就是δ'(Al3Li)亚稳相的前兆结构和生长胚胎；由於Al-Li-空位有序偏聚晶胞的Al-Li键络比基体键络要强许多，因此，淬火过程中合金生成的Al-Li-空位偏聚晶胞对合金过饱和固溶体起主要强化作用；后续析出的δ'(Al3Li)亚稳相键络各项异性显著，键络强度明显提高；由於Al3Li与基体共格，其大量均匀弥散析出起到提升基体整体键络强度，同样对合金产生强化作用。

In addition, some modifications on several computational methods are also presented. Using LMTO method the electronic structure of several systems are studied, and some results are obtained. They are: The ideal Nb (100) surface has three surface states, the multi-layer relaxed surface has two surface states. The surface energy of the ideal surface is higher than that of the relaxed surface, that means that the multi-layer relaxed surface is more stable than the former one, which supports the LEED results. The mono-layer relaxed Ag (111) surface is the most stable one among several" stable surface models"presented by several researchers. The surface energy of Ag (111) surface is higher than that of surface Ag (001), which supports some experimental results such as different reaction rate at different surface orientations for the same material. The surafce states of Si (111) surface not only locate near the Fermi level, but also in the valence band, which agrees well with Cohen's conclusion. Si (111)-H is an effective model for analysing the surface states and H adsorbed on the back surface is a good method for improving the convincingness of the results obtained on thinner slab models. The surface stability depends on three different kinds of MoSi〓(001) surfaces, the surface with mono-layer Si is the most stable one, and the surface with Mo at the first layer is the most unstable one among them. These are consistant with the Kemoda's experimental results. The valence bands of clean or K adsorbed CdTe (111) surface agrees well with the synchrotron radiation studies. The surface of CdTe (111) consists of four kinds of surface models which show different surface electronic structures and different surface structure stabilities. The conclusion agrees well with Wu's experimental work. The different absorbed alkali metals on the CdTe (111) surface give different adsorption characteristics which have relations not only with the valence electrons, but also with the core ones of the alkali metals. The electonic structures of Si-C alloys are different from that of Si-Ge alloys, and the energy band gaps of Si-C alloys do not increase linearly with Carbon concentration, our conclusion supports Alexander's results, but conflicts with Soref's one.

现分述如下： LMTO方法及其应用方面：1）通过对Nb（100）表面电子态分析发现清洁理想表面有三个表面态，多层弛豫表面有两个表面态；表面能大小说明多层弛豫表面更稳定，支持了LEED结果。2）通过对采用不同方法获得的几种不同Ag（111）表面稳定结构的表面能计算分析，给出了单层弛豫表面为Ag（111）表面的最稳定结构；从Ag（111）单层弛豫表面和Ag（001）表面的表面能比较，发现了Ag（001）表面表面能要比Ag（111）小的，表明了同种物质不同表面取向将表现出不同物理、化学性质，这是与实验中得出的结论是吻合的，3）通过对Si（111）表面态分析，不仅发现了Si（111）表面不仅具有居于费米能级附近的悬挂键所对应的表面态，而且还有很多表面态位于价带能量范围内，与Cohen等结果一致，H饱和slab模型背表面相当于增加了slab层的厚度，是一有效的变相增加slab层厚的方法，弛豫表面较清洁理想表面价带谱们低能端的少许移动，预示着总能降低，说明弛豫表面较清洁理想表面稳定。4）MoSi〓具有三种表面，从费米能级上态密度值大小得到单层Si表面最稳定，Mo原子为表层原子的表面最不稳定，双层Si原子表面居中的结论，这与Kemoda等人实验结果是一致的。5）通过对CdTe（111）表面表面电子态、表面结构稳定性及表面H、碱金属吸附的电子结构系列研究，不仅得出了CdTe（111）清洁及碱金属K吸附价带谱与同步辐射光电子谱相吻合的结果，而且发现了CdTe（111）表面具有四类不同原子近邻特征，表现出四类不同的表面结构及电子结构特征：不同表面态分布、不同的表面结构稳定性（表层原子与次层原子成三键有一悬挂键的表面要比表层原子与次层原子成一键有三悬挂键稳定（与Wu等人实验结果一致））、不同的H吸附特性。

Glyceraldehyde has a single asymm- etric carbon atom﹙the central one﹚ and so two stereoisomer﹙also called optical isomer﹚ are possible, that is two forms of glyceraldehyde, denoted as D- and L-glyceraldehyde, which are mirror images of each other

D-葡萄糖碳原子键合C-5的羟基和氢原子的位置与D-甘油醛相同称为D-型，同样L-型的甘油醛衍生出来的单糖称为L-型糖。

The results show that the calculated elastic properties are close to the experimental results. The high value of Poisson's ratio and low value of elastic anisotropy ratio imply that the interatomic force in ZrCr2 is weakly directional.

结果表明：计算得到的ZrCr2 Laves相的弹性性质与实验结果相近，其泊松比和弹性各向异性系数大小说明ZrCr2 中原子键合的方向性并不强烈； ZrCr2 Laves相的内禀和外禀层错能分别为112 mJ/m2和98 mJ/m2。

Crystal lattice constants are close to other experiment results. Three kinds of chemical bonds exist among Mg and B atoms, between magnesium and boride is ionic bond and metallic bond is the predominant interaction in the layer formed by magnesium atoms. A strong covalent bond in the form of sp2 hybrid between boride atoms is the most important factors which can affect the transition temperature of MgB2. Population analysis clearly shows that electrons are transferred from Mg to B, as a result, the electron-phonon coupling in the layer of B is very strong.

规范保守赝势的计算结果表明，晶格常数与实验值误差在很小的范围内，分析了引起MgB2(001)面结构超导转变时电子浓度和偏态密度的变化情况，发现构成该超导体结构的成键有3种，着重从结构的电子浓度变化分析了其超导特性，六角蜂窝状结构中硼原子间相互作用为sp2杂化的共价键，镁原子和硼原子之间是离子键结合，镁原子层是金属键结合，镁原子的价电子部分转移到硼原子的pz轨道，部分电子为镁原子层共用。

Halogenated aromatic compounds with great q〓(the most negative net atomic charges on an atom of the molecule), ENC (electron-nuclear attraction energy of the one-center term for the carbon atoms of the weakest carbon-halogen bond), qc (thenet atomic charges on the carbon atom of the weakest carbon-halogen bond) and E〓 tend to be reductively dehalogenated slow, while halogenated aromatic compounds with high values of △E (the difference of front-line orbital energy), EEC (electron-electron repulsion energy of the one-center term for the carbon atoms of the weakest carbon-halogen bond), Mw, q〓 and α tend to be reductively dehalogenated fast.

卤代芳烃化合物的整个分子的最负的原子净电荷，键序最小的碳卤键中碳原子的单中心项电子-核吸引能，该碳-卤键上碳原子的净电荷和E〓与该卤代芳烃化合物还原脱卤的速率常数负相关；而前线轨道间隙能，键序最小的碳卤键中碳原子的单中心项电子-电子推斥能，Mw，q〓和α与该卤代芳烃化合物还原脱卤的速率常数正相关。

Based on density functional theory and electronegativity equalization principle,applying an atom-bond electronegativity equalization σπ model,using a separated program,we calculated the charge distributions and dipole moments of guanine tautomers.

以密度泛函和电负性均衡原理为基础发展的原子-键电负性均衡方法的σπ模型。并结合自编程序，计算了鸟嘌呤五种异构体的电荷分布和偶极矩，计算结果表明，所计算出的电荷分布可以和从头算结果很好地关联。所计算的偶极矩与其它从头计算方法和力场方法相比总体趋势相同，进一步说明了ABEEMσπ模型的合理性

For the calculations of Mon (n= 2-55) clusters, the linear and planar clusters have a strong tendency to form diatomic pairs to assemble short-long bonds alternation structures which makes them like non-metallic clusters, the short bonds are characterized as covalent non-metallic bonds and the long ones are much like weak metal bonds.

本文首先计算了各种不同结构的Mon（n=2-55）原子簇，发现一维和二维Mo原子簇表现出了一定的非金属原子簇的性质，簇中原子有明显的成双原子对趋势，致使原子簇具有短-长键交替的几何结构，短键和长键分别呈现强共价键和弱金属键的特性。

A noteworthy one is that we have obtained the Fukui function and local softness of πbond region for the first time, only by which we can explain and predict theregioselecitivity of Diels-Alder reaction etc.

可见原子-键电负性均衡方法中的σπ模型不仅具有简便易行的优点，而且得到的各种反应标度或稳定性指标具有计算简便、概念直观、易于使用等特点。

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。