JavaScript语言作为一门弱类型语言,由于其函数的第一类对象(First Class Object)性,无论是采用函数式编程还是面向对象编程使用起来都非常灵活。随着近几年Java Script生态圈发展的火热和不断成熟,各种项目的编码量和复杂度都在呈几何...JavaScript语言作为一门弱类型语言,由于其函数的第一类对象(First Class Object)性,无论是采用函数式编程还是面向对象编程使用起来都非常灵活。随着近几年Java Script生态圈发展的火热和不断成熟,各种项目的编码量和复杂度都在呈几何级数增长,而JavaScript面向对象编程中的继承机制在其中扮演的作用也越来越重要,但使用现状却非常不规范。详细分析JavaScript的继承核心机制,然后提供几种继承的实现方式,并分析各自相应的优缺点和使用场景;同时通过分析John Resig发布的其著名开源框架中的一段核心源码,展示继承机制在JavaScript框架级项目开发中的应用。展开更多
Short chain chlorinated paraffins （SCCPs） are not only research focus of environmental issues but also interesting model mol- ecules for organic chemistry which exhibit diverse conformation preference and intramolec...Short chain chlorinated paraffins （SCCPs） are not only research focus of environmental issues but also interesting model mol- ecules for organic chemistry which exhibit diverse conformation preference and intramolecular noncovalent interactions （NCIs）. A systematic study was conducted to reveal the conlk）rmation preference and the related intramolecular NCIs in two C^-isomers of SCCPs, 5,5,6,6-tetrachlorodecane and 4,4,6,6-1etrachlorodecane. The overall conformation profile was deter- mined on the basis of relative energies calculated at the MP2/6-311＋＋G（d,p） level with the geometries optimized by B3LYP/6-31 l＋＋G（d,p） method. Then, quantum theory of atoms in molecules （QTAIM） has been adopted to identify the NCls in the selected conformers of the model molecules at both B31~YP/6-31 l＋＋G（d,p） and M06-2X/aug-cc-pvdz level. Different chlorine substitution modes result in varied conformation preference. No obvious gauche effect can be observed tk）r the SCCPs with chlorination on adjacent carbon atoms. The most stable conformer of 5,5,6,6-tetrachlorodecane （tTt） has its three dihedral angles in the T configuration, and there is no intramolecular N（3s found in this molecule. On the contrary, the chlorination on interval carbon atoms favors the adoption of gauche configmation for the H C C CI axis. Not only inlramolecular H-..CI contacts but also H---H interactions have been identified as driving forces to compensate the instability from steric crowding ot the gauche configuration. The gggg and g＇g＇g＇g＇ conformers are the most popular ones, while the populations of tggg and tg＇g＇g＇ conformer are second to those of the gggg and g＇g＇g＇g＇ conformers. Meanwhile, the M06-2X method with large basis sets is preferred for identification of subtle intramolecular NCIs in large molecules like SCCPs.展开更多
文摘JavaScript语言作为一门弱类型语言,由于其函数的第一类对象(First Class Object)性,无论是采用函数式编程还是面向对象编程使用起来都非常灵活。随着近几年Java Script生态圈发展的火热和不断成熟,各种项目的编码量和复杂度都在呈几何级数增长,而JavaScript面向对象编程中的继承机制在其中扮演的作用也越来越重要,但使用现状却非常不规范。详细分析JavaScript的继承核心机制,然后提供几种继承的实现方式,并分析各自相应的优缺点和使用场景;同时通过分析John Resig发布的其著名开源框架中的一段核心源码,展示继承机制在JavaScript框架级项目开发中的应用。
基金the Chinese Academy of Sciences (KZCX2-YW-BR-25, XDB14030500, YSW2013B01)the National High Technology Research and Development Program of China (2013AA065201)
文摘Short chain chlorinated paraffins （SCCPs） are not only research focus of environmental issues but also interesting model mol- ecules for organic chemistry which exhibit diverse conformation preference and intramolecular noncovalent interactions （NCIs）. A systematic study was conducted to reveal the conlk）rmation preference and the related intramolecular NCIs in two C^-isomers of SCCPs, 5,5,6,6-tetrachlorodecane and 4,4,6,6-1etrachlorodecane. The overall conformation profile was deter- mined on the basis of relative energies calculated at the MP2/6-311＋＋G（d,p） level with the geometries optimized by B3LYP/6-31 l＋＋G（d,p） method. Then, quantum theory of atoms in molecules （QTAIM） has been adopted to identify the NCls in the selected conformers of the model molecules at both B31~YP/6-31 l＋＋G（d,p） and M06-2X/aug-cc-pvdz level. Different chlorine substitution modes result in varied conformation preference. No obvious gauche effect can be observed tk）r the SCCPs with chlorination on adjacent carbon atoms. The most stable conformer of 5,5,6,6-tetrachlorodecane （tTt） has its three dihedral angles in the T configuration, and there is no intramolecular N（3s found in this molecule. On the contrary, the chlorination on interval carbon atoms favors the adoption of gauche configmation for the H C C CI axis. Not only inlramolecular H-..CI contacts but also H---H interactions have been identified as driving forces to compensate the instability from steric crowding ot the gauche configuration. The gggg and g＇g＇g＇g＇ conformers are the most popular ones, while the populations of tggg and tg＇g＇g＇ conformer are second to those of the gggg and g＇g＇g＇g＇ conformers. Meanwhile, the M06-2X method with large basis sets is preferred for identification of subtle intramolecular NCIs in large molecules like SCCPs.
