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宋占奎 《河北软件职业技术学院学报》2001,3(2):71-73
本文不但给出了曲面的两相交曲线的交角的解法，而且给出了几种特定条件下的曲线的轨线方程的解法，最后给出了与子午线交定角的轨线方程的解法。 相似文献
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Shalini M Yogeeswari P Sriram D Induja S 《Journal of Zhejiang University. Science. B》2007,8(1):45-55
Objective： To study the effect of halo substitution on disubstituted aryl semicarbazones on the anticonvulsant potential and model the activity based on quantum mechanics. Methods： A series of twenty-six compounds of N^4-（4-bromo-3-methylphenyl） semicarbazones were synthesized and evaluated for the anticonvulsant activity in the maximal electroshock seizure （MES） and subcutaneous pentylenetetrazole （scPTZ） seizure threshold tests. Some potential compounds were also tested in the subcutaneous strychnine （scSTY） and subcutaneous picrotoxin （scPIC） seizure threshold tests. The synthesized compounds were tested for behavioral impairment and CNS （central nervous system） depression in mice. Quantum mechanical modelling was carried out on these compounds to gain understanding on the structural features essential for activity. Results： Some compounds possessed broad spectrum anticonvulsant activity as indicated by their effect in pentylenetetrazole, strychnine, picrotoxin and maximal electroshock seizures models in resemblance to other aryl semicarbazone derivatives reported earlier. The higher the difference in HOMO （highest occupied molecular orbital） and LUMO （lowest unoccupied molecular orbital） energy levels was, the greater was the activity profile. Conclusion： The pharmacophoric requirements for compounds to exhibit anticonvulsant activity that includes one aryl unit in proximity to a hydrogen donor-acceptor domain and an electron donor have been justified with the molecular orbital surface analysis of the synthesized compounds. 相似文献
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利用协同反应模型和ＥＨＣＯ－ＡＳＥＤ量子化学方法，对具有不同侧基的固态二乙炔拓扑聚合反应的势能曲线进行了计算，并对其轨道对称性以及能隙随反应坐标的变化进行了分析。很好地解决了文献中用Ｗｏｏｄｗａｒｄ－Ｈｏｆｆｍａｎｎ轨道对称守恒原理对此类反应进行分析的结果与实验事实相矛盾的问题，指出了此类反应既是光允许，也可以是热允许的原因。对此类反应的侧基效应进行的研究结果表明，侧基电子亲和势的变化对该类反应的反应机理及活化能影响较小，但对产物热力学稳定性的影响则较为显著。 相似文献
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原子核外电子在外界磁场作用下的轨道运动会对高速运动的电子磁矩产生一个反向的作用效果,从而导致物质具有抗磁性等宏观效应。那么在电动机的感应线圈中为什么没有类似的现象呢？这是大学物理教学过程中,很多学生比较疑惑的地方,这里我们通过分析这两种模型,做一个简要说明。 相似文献
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键级和化合价的分子轨道理论 总被引：1，自引：0，他引：1
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. 相似文献
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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). 相似文献
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化学缓蚀剂在青铜器文物保护中的理论分析 总被引：1，自引：0，他引：1
利用量子化学计算泛函密度理论中的B3LYP方法,在6-31 +G(d)基组上,对8种常见的在青铜器文物保护中使用的化学缓蚀剂化合物分子进行了结构和化学反应活性分析.结果表明化学缓蚀剂分子具有类平面型的共轭结构,其活性中心主要在氮原子上,通过对所有缓蚀剂分子的最高占有轨道(HOMO)、最低空轨道(LUMO)和能量差(ELUMO-EHOMO)△E分析后发现,苯并三氮唑(BTA)和2-氧代苯并咪唑(MBI)对青铜文物的保护性能较好. 相似文献
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