A novel molecular connectivity method

This paper presents a new molecular connectivity wherein the atomic delta value is weighted by the Mulliken bond order, and thus connects effectively the molecular orbital theory with the topological theory and converts the molecular connectivity method into a novel quantum-topology method. Comparison of the atomic delta value of the molecular connectivity with the value of the Mulliken bond order, showed that they have similar physical meanings. The calculated new molecular connectivity indexes of some typical hydrocarbons showed good correlatin with their volumes, hydrophobic constants and thermodynamic properties, respectively.     

键级和化合价的分子轨道理论

本文译自美国《Journal of chemical Education》1988年第8期.作者简介了密立根布居数分析法,并以此为基础讨论了键级和化合价,应用了别致的原子轨道线性组合分子轨道理论(LCAO—MO)的矩阵公式.最后给出了一些简单分子的计算结果,以说明这个理论的应用.     

木犀草素分子密度泛函理论研究

采用Gussian03软件包,在B3LYP/6-31G(d,p)基组下计算了木犀草素分子的键长、键角、二面角、最高占据轨道能、最低空轨道能及慕林肯电荷等结构参数,利用木犀草素分子的结构参数分析了木犀草素分子的活性部位,这为木犀草素的药理活性研究提供了理论依据.     

计算环烷烃摩尔折射度的新方法

根据分子结构的特点 ,发展了一种计算环烷烃摩尔折射度的新方法 .对 2 3 2种环烷烃的计算结果表明 ,摩尔折射度计算值十分接近实验值 ,平均误差 0 2 8%,计算精度显著优于文献方法     

双原子分子的键长与原子结构之间定量关系的研究

根据原子结构的特点,探讨了双原子分子的键长与组成双原子分子的原子结构之间的关系,发现双原子分子的键长与组成双原子分子的原子结构之间存在着良好的定量关系,据此提出一种直接根据原子结构预测双原子分子键长的方法．结构表明,预测值与实验值的一致性令人满意,平均误差0．0058nm．     

应用基团键贡献法预测烷烃、脂肪醇和硫醇的摩尔折射度

根据分子中基团之间的连接性,提出一种计算有机化合物加和型性能的新方法－－基团键贡献法,该方法将基团贡献法和化学键贡献法有机地结合在一起,既考虑分子中基团的特性,又考虑基团间的连接性（化学键）,同时具有基团贡献法和化学键贡献法的特点。应用基团键贡献法对烷烃、脂肪醇和硫醇摩尔折射度的计算结果表明,计算值十分接近实验值,与现有方法相比,计算精度提高了约一个数量级。     

有机锡氧四元杂环化合物(μ-O)_2Sn_2R_4(R:Me,Et)的理论研究

利用Gaussian03W在LANL2DZ基组水平对有机锡氧四元杂环结构化合物(μ-O)2Sn2R4(R:Me,Et)进行理论研究,优化了几何构型,获得键参数,分析了化合物的Mayer键级,计算出分子体系能、分子最高占据轨道能和分子最低未占据轨道能,经Mulliken布居分析原子净电荷分布,计算出原子轨道对分子轨道的组成贡献。结果表明,除(μ-O)2Sn2Me4外的标题化合物均稳定,为有机锡氧四元杂环化合物(μ-O)2Sn2R4(R!Me)的合成提供理论基础。     

应用基团键贡献法计算环烷烃的密度

根据分子中基团的特性和连接性 ,发展了一种计算环烷烃密度的新方法———基团键贡献法 该方法考虑分子中基团的特性 ,又考虑基团间的连接性 (化学键 ) ,同时具有基团贡献法和化学键贡献法的特点 .应用基团键贡献法对 2 2 3种环烷烃密度的计算结果表明 ,计算值与实验值的一致性令人满意     

多硝基芳香化合物撞击感度的理论研究

采用密度泛函的方法，在3—21G基组水平上，对五种多硝基芳香化合物TNA(Ⅰ)、2，3．4，6-四硝基苯胺(Ⅱ)、五硝基苯胺(Ⅲ)、DATB(Ⅳ)、TATB(Ⅴ)炸药的撞击感度进行了理论研究，探讨苯环上引入氨基和硝基对该类炸药撞击敏感度的影响。结果表明，利用Mulliken键级可以很好的解释分子的撞击感度，氨基引入苯环后，炸药的撞击感度减小，硝基引入苯环后，撞击感度也发生了变化，其撞击敏感度顺序为：Ⅰ＞Ⅲ＞Ⅱ＞Ⅳ＞Ⅴ。     

中专化工专业原子结构理论教学初探

在核外电子运动状态的描述和s、p电子云图教学的基础上,如何进一步将核外电子排布、轨道表示式、电子云图一一对应联系起来,并用电子云图来表示简单原子结构的“立体”模式,从而提高学生对原子结构的理解,为化学键及分子结构理论的学习打下基础等方面提出几点教学体会。     

原子点价的不断修正

每一种新的分子连接性指数的定义,实际上是一种原子点价的新定义,因此原子点价的不断修正和改进,成为目前化学工作者探讨的焦点,故而有必要将不同点价加以比较,了解其存在的缺陷和改进优越性.     

A Student Evaluation of Molecular Modeling in First Year College Chemistry

This three-year study involved an evaluation of molecular modeling by students in first year college chemistry. The molecular modeling program utilized was Spartan (Wavefunction, Inc., Irvine, California) on a UNIX-based platform with Silicon Graphics Indigo series workstations. A treatment group of 129 students visited a computer room four times during the semester for two-hour sessions. They completed exercises on periodic trends in atoms, structure of molecules, electronic structure of molecules such as MO and valence bond theory, and properties of organic molecules. The students were required to complete an evaluation of the molecular modeling computer experience at the end of the semester regarding aspects such as: effectiveness, integration with course content, interest, benefit, and advantages and disadvantages. Also obtained through the evaluation were students' opinions regarding the helpfulness of the molecular modeling computer experience for 3-D visualization of atomic and molecular structure and whether their understanding of atomic and molecular structure was enhanced. The first two years of the study constituted a pilot study and data for this study were obtained in the third year. Though the specifics are not reported here, quantitatively the achievement of the treatment and non-treatment groups was also assessed. There was a significant difference in achievement on the Final Exam of the semester (p = 0.0067) between the treatment and non-treatment groups on multiple choice questions pertaining to concepts of resonance, dipole moment, and atomic/molecular stoichiometry.     

Bond property test of reinforced concrete with all soaking and impressed current method corrosion

In order to research the bond properties between corroded reinforcement bars and concrete, reinforcement bars with different diameters and different types and concrete with different strength levels were treated specially with all soaking and impressed current method, and the bond properties were measured with the pull-out test. The comparative analysis of the bond properties of corroded reinforcement bars was carried out. The results showed that the types of reinforcement bars and concrete had great influence on the bond strength. The corrosion and volume expansion of reinforcement bars made concrete in tensile condition, which tended to produce cracks in parallel reinforced direction. The typical bond failure of plain reinforcement bars was pull-out, while the typical bond failure of ribbed reinforcement bars was split. The bond strength between corroded reinforcement bars and concrete increased with the increase of concrete strength. The bond strength of plain and ribbed reinforcement bars showed a decreasing trend after the first increase with the increase of the extent of corrosion. Through the test, the coefficients of the bond strength of plain and ribbed reinforcement bars were given, respectively.     

具有凸多面体不确定参数Delta算子时滞系统的可靠保性能控制

研究Delta算子描述的线性不确定时滞系统的可靠保性能控制问题。考虑系统含有具有凸多面体不确定性参数和连续模型执行器故障,根据Lyapunov稳定性理论,给出对于所有允许的不确定性和执行器故障．均使闭环系统渐近稳定且给定性能指标具有一定上界的状态反馈控制器的存在条件,由此提出相应控制器的设计方法。通过数值算例验证了设计方法的可行性。     

支持向量机在多氯代二苯并呋喃logKow中的应用

应用G98W程序包中的量子化学密度泛涵（DFT）方法，在B3LYP／6—31G（d）水平上，对51种二苯并呋喃及其衍生物（PCDFs）进行几何构型全优化。优化后所得分子的最高占据轨道能量、二苯并呋喃环上1，2，3，7四个原子静电荷密度作为PCDFa分子结构描述符。应用支持向量机构建多氯代二苯并呋喃logKow的定量构效（QSAR）关系模型，所建模型的预测值与实验值吻合的很好，经留一交叉校检法检验该模型，该模型具有良好的稳健性，有一定的应用价值．     

Study on the prediction of visible absorption maxima of azobenzene compounds

The geometries of azobenzene compounds are optimized with B3LYP/6-311 G* method, and analyzed with nature bond orbital, then their visible absorption maxima are calculated with TD-DFT method and ZINDO/S method respectively. The results agree well with the observed values. It was found that for the calculation of visible absorption using ZINDO/S method could rapidly yield better results by adjusting OWFπ-π (the relationship between π-π overlap weighting factor) value than by the TD-DFT method. The method of regression showing the linear relationship between OWFπ-π and BLN-N (nitrogen-nitrogen bond lengths) as OWFπ-π=-8.1537 6.5638BLN-N, can be explained in terms of quantum theory, and also be used for prediction of visible absorption maxima of other azobenzne dyes in the same series. This study on molecules' orbital geometry indicates that their visible absorption maxima correspond to the electron transition from HOMO (the highest occupied molecular orbital) to LUMO (the lowest unoccupied molecular orbital).     

硅烷摩尔体积与其分子结构定量关系的拓扑化学研究

根据分子中基团的特性和连接性 ,借助于拓扑化学方法探讨了硅烷的摩尔体积与分子结构之间的定量关系 ,将基团贡献法和拓扑方法结合在一起 ,发展了一种根据分子结构信息计算硅烷摩尔体积的方法 ,该方法具有基团贡献法实用范围广和拓扑方法计算结果可靠的特点 ,对硅烷的计算结果表明 ,摩尔体积计算值与实验值的一致性令人满意 ,计算结果优于基团贡献法 .     

优化新时期高校思想政治理论课教学方法的现实路径探析

近些年,伴随着我国高校思想政治理论课教学改革,在高校思想政治理论课教学方法的改革探索过程中又出现了一些新情况、新问题。笔者在高校思想政治理论课教学实践的基础上,为提高高校思想政治理论课的实效性,对这些改革过程中出现的新问题进行梳理,以为进一步深化高校思想政治理论课教学改革奠定理论基础。     

杂化轨道理论的探讨

杂化轨道理论是现代价键理论的一部分．也是大学无机化学教学的一个难点。本文从原子轨道为什么需要杂化：原子轨道为什么可以杂化；杂化后可形成哪些杂化类型来说明杂化轨道理论。从而进一步总结杂化对元素及分子性质的影响。     

基于中间态是三聚物的相干布局囚禁

用中间态为三聚物分子态的光缔合的方法来考虑原子-分子的转换过程,最终找到原子-分子相干布局囚禁态,并使其相应的中间三聚物分子态自始至终布局一直为零,通过零布局的中间态,更多的更有效的原子-四聚物分子能够产生,并可以有效的应用到物理实验中.为原子-四聚物分子的产生提供了新的有效路径.