查询词典 Lewis

This thesis is constituted by four parts: In the first part a summarization is given on the main total synthetic methods of isoflavones, for example, deoxybenzoin method which generally involves two steps wherein a phenol is reacted in the presence of a Lewis acid with phenylacetic acid to generate an intermediate deoxybenzoin which is then cyclized with a one carbon electrophile.

本论文主要工作包括四部分：第一章综述了近年来全合成异黄酮的主要方法：脱氧安息香法，是以多羟基苯酚与苯乙酸或苯乙腈在Lewis酸存在下，反应生成中间体脱氧安息香，然后再与亲电碳试剂进行关环反应生成异黄酮。

The free phosphonic groups shielded most of the Lewis-acid sites on the surface of zirconia and imparted negative charges on the surface at high pH, resulting in excellent resolution for phenols and a great improvement for the separation of benzoic acids.

在该固定相上，酸性化合物的色谱性能得到明显改善，硝基酚、苯二酚等在氧化锆上通常难以洗脱的酚类化合物，均得到了高效分离。

Lewis acidity is considered to be responsible for the high photoactivity at 950 °C.

而路易士酸被认为是锻烧950 ℃之样品有高活性的主要原因。

Lewis Carroll. Halftone photomechanical reproduction of photograph.

路易士。卡洛尔的照片，以网版照相技术翻印。

We screened a set of Lewis base organocatalysts derived from chiral pipecolinic acid and tert-butanesulfinamide for the reduction of-N-Cbz-1- phenylpropenamine, including newly designed ones and some of those previously developed in our lab. However, only moderate stereoselectivities, albeit high yields were obtained.

在本课题组前期研究的基础上，我们筛选并设计了一系列以手性哌啶酸和叔丁基亚磺酰胺为母体的有机小分子路易斯碱催化剂，它们能催化三氯氢硅对-N-苄氧羰基-1-苯基丙烯胺的不对称还原，获得很高的收率和中等的对映选择性，并且具有很好的底物普适性。

Starting from chiral proline, pipecolinic acid, piperazine-2-carboxylic acid and 1,2-diphenyl amino alcohol, a series of structurally simple and easily prepared amides were developed as highly effective Lewis basic organocatalysts for the asymmetric reduction of imines with trichlorosilane as the reducing agent, which promoted the reduction of N-aryl imines with high yields and excellent enantioselectivities with an unprecedented substrate spectrum.

本文分别由手性脯氨酸、哌啶酸、哌嗪酸以及氨基醇出发，设计和合成了一系列结构新颖、合成简便、性能优良的酰胺类有机小分子路易斯碱催化剂，以廉价的三氯氢硅为氢源，用这些催化剂催化亚胺不对称还原，得到了非常优良的收率、对映选择性和前所未有的底物普适性。

The method builds model of lung cancer of small rat Lewis, those who evaluate content of content of capsule of antler glossy ganoderma resist tumor and the influence that resist oxidation and noxiousness of platinic to arranging kidney, compare content of content of capsule of antler glossy ganoderma with MTT law the cellular poison of individual plant of cell of tumour of person of different to 10 kinds outside body type is active.

方法建立小鼠Lewis肺癌模型，评价鹿角灵芝胶囊内容物的抗肿瘤和抗氧化功能及对顺铂肾毒性的影响，并用MTT法比较鹿角灵芝胶囊内容物在体外对10种不同类型人肿瘤细胞株的细胞毒活性。

In order to further improve the catalytic activity and investigate the influence of catalyst acidic properties on the catalytic activity, acid-treated montmorillonite and molecular sieve Hβwere modified by loading Lewis acid and protonic acid treatment.

为了进一步提高催化剂的催化活性和考察催化剂酸性质对催化剂活性的影响，对酸化蒙脱土和Hβ分子筛进行了改性处理并考察了它们改性后的催化活性。

Hydrothermal reactions makes water a Bronsted base-acid and act as an effective catalyst and the metal ions represent Lewis base character. The conversion process occurs in a very complex network of parallel, consecutive and equilibrium reactions, and the last step being the catalyzed Cannizzaro-type reaction of pyruvaldehyde to lactic acid.

nsted酸碱并具有一定的催化作用，金属离子在水热催化降解丙酮醛生成乳酸中表现出Lewis碱的特性，能与丙酮醛生成金属复合物，最终生成乳酸，此反应过程符合Cannizzaro反应特性。

In the Lewis and Chambers example, restaurants have been seedily increasing their prices.

在刘易斯和商会例如，餐馆已seedily提高其价格。

Continuously improve the production mechanism, to provide customers with better quality products and services.

不断的完善生产机制，给客户提供更优质的产品及服务。

B:Yes, he was the very prize-winner in the court tennis ten years ago?

是的，他是十年前的世界网球冠军。