查询词典 elasticity of substitution

An improved chemical method for the determination of the molar substitution degree of hydroxyethyl guar gum has been described.

本文用模型小分子一缩二乙二醇的醚键断裂实验证明了可行性，羟乙基瓜尔胶上的羟乙基链段与过量对甲苯磺酸-乙酸酐在130℃下反应14hr，醚键完全断裂生成酯，并在pH=11条件下煮沸1hr使酯完全水解，转变为乙二醇。

By defining several localindices which can be easily calculated from these ground-state wavefunctions, we first succeeded in explaining bond lengths, orientation ofelectrophilic aromatic substitution, and local aromaticity of these benzenoidhydrocarbons within the VB theory. Moreover, the energy splittings betweenthe ground state and first excited state are applied to correlate with theiroverall aromatic characters, the results are also in good agreement withrelated predictions from MO theory.

通过定义一些可由基态波函数直接计算的局域指标，首次在VB模型下成功地解释了苯型烃的键长、亲电取代反应的方向及局域芳香性，并用基态与第一激发态的能量差讨论了这些分子的整体芳香性，得到了与分子轨道理论的预测基本平行的结果。

The wide ionic substitution in NZP materials makes their physical properties tailorable to meet application needs when changing the composition. Thermal expansion behavior of NZP ceramics is one example.

NZP型陶瓷材料的最大特点在其晶体结构中，三种阳离子(Na/sup +/，Zr/sup 4+/，P/sup 5+/)的晶格位置都有广大的取代空间，使得NZP型材料可以藉由成分的变换，来调整其物理性质，以配合实际应用上的需求。

Electrophilic substitution reactions''' are chemical reactions in which an

亲电取代反应'''一种

However, by the time the students' reports were due, the former topic had been discussed in the classroom, and students under-stood that the chlorination was an example of an electrophilic aromatic substitution.

然而，到了学生的报告该交的时候，前面的主题已经在课堂上讨论过了，学生已经理解了氯化是亲电芳基取代的一个例子。

In electrophilic substitution in

在脂肪族化合物的亲电反应中，

Revealed high benzene electrophilic substitution reactions and not reacted reasons, strengthened the laws of scientific chemical benzene, helps people in-depth research and study of benzene and aromatics of the structure and nature.

揭示了苯容易发生亲电取代反应和不易发生加成反应的原因，增强了苯化学的规律性和科学性，有助于人们深入研究和学习苯乃至芳香烃类的结构和性质。

Here, Risk Assessment Code matrix method and runaway scenario analysis method were used to evaluate the thermal runaway criticality, and some reaction conditions were compared and analyzed as well. At last, based on the experimental results, the theoretical calculation was adopted to analyze the decomposition of nitration product and the electrophilic substitution mechanism of these nitration reactions. All these work are of important value for the correct evaluation of thermal risk and the decrease of chemical reaction runaway accidents.

本文采用风险矩阵法和失控情景分析方法评估此反应的热失控危险，对反应中的一些影响因素展开比较和分析，并结合实验结果，从理论角度进一步分析了各硝化产物分解的难易性和硝化反应亲电取代的硝化机理，这些工作对准确评估反应的热危险，减少反应失控事故具有重要的参考价值。

American descriptive linguistics ; grammar study of Chinese language ; substitution of identical form ; functional standard ; class of shape ; syntactical structure ; immediate constituents ; sentence as unit of analysis ; phrase as unit of analysis

本文集中从四个方面探讨描写语言学对汉语语法学的影响：语素分析法及词类归并原则的运用；突出短语结构在句法学中的地位，从形式入手分析句法结构、划定句子成分；直接成分分析法的运用；对汉语语法体系嬗变的影响。

Two substitution derivates of β CD His and β CD His 2 was synthesized and characterized respectively,which simulate deoxyribonuclease,their activity of hydrolysis deoxyribonucleic acid are compared with DNaseⅠ′s.

合成了β-环糊精的组氨酸一取代和二取代衍生物(简写β- CD- His和β- CD- His2 )并对其结构进行了表征。

Listen,point and check your answers.

听，指出并且检查你的答案。

Warming needle is one of effective treatment methods for knee arthralgia aggravated by cold,and it is simple,safety,so it should be developed in clinical acupuncture and moxibustion extensively.

但以本院科针灸门诊在2005年1月—2006年6月期间共收治膝痛患者100余例，经过临床的诊断后，其中施以温针治疗的48例，疗效显著，报道如下。1临床资料本组病例48