查询词典 substitution group

The present invention relates to a water-soluble associative cellulose ether having a DP viscosity from 250 to 20,000 mPa's, measured at a concentration of 1 % by weight, and a molecular substitution, MS, from 0.0001 to 0.005 of a hydrophobic substituent containing an unsubstituted or substituted hydrocarbon group of 8-24 carbon atoms.

本发明涉及一种水溶性缔合纤维素醚，其在1重量％的浓度下测量的DP粘度为250-20，000mPa's，并且含有未取代或取代的C8-C24烃基的疏水取代基的分子取代度MS为

Chlorine atoms were selectively introduced into the chlorin ring based on different reactivity between vinyl group at 3-position and 20-meso position by electrophilic addition and electrophilic substitution using hydrogen peroxide/hydrochloric acid, N-chlorosuccinimide, hydrogen chloride (or concentrated hydrochloric acid) as chlorinating reagent.

以过氧化氢/盐酸、N-氯代丁二酰亚胺、氯化氢为氯化剂，根据3-乙烯基和20-meso-位的不同化学反应活性，通过亲电加成和亲电取代反应，在二氢卟吩环上选择性地引进氯原子，完成8种未见报道的具有叶绿素-a基本碳架的氯代二氢卟吩衍生物的合成。

There are three different nucleophilic reagent respectively reaction with m-dinitrobenzene ramification at distint alkaline term:With the nitrobenzene 、 m-nirtobenzenesulfone sodium salt 、 2.4-dinitro chlorobenzene 、 m-dinitrobenzene for bottom thing, benzyl cyanide、 benzyl chloride、 benzyl chloropyridine、is a nucleophilic reagent reaction for under the different term proceeds a series reaction. At the same time ,discuss about the impact factor to nucleophilicity such as the number of attract electron group、 ability of attract electron and the nucleophilic substitution reaction part.

设计了三类不同的亲核试剂分别与活化芳环在不同的碱性条件下发生反应：以苄基氰、苄基氯化吡啶为亲核试剂，以硝基苯、间二硝基苯、间硝基苯磺酸钠、2，4-二硝基苄基氯为底物进行亲核取代反应；并且对亲核试剂的体积效应、溶剂效应对亲核性影响，底物上吸电子基团的数目、吸电子能力对亲电性的影响，以及亲核取代反应的发生部位受哪些因素影响进行探讨。

The effects of the substitution of variant group were discussed and somehelpful conclusions were drawn.

对卟啉系列衍生物的取代基效应进行了讨论，得到一些有益的结论。

But the prerequisite was still not to tolerate the substitution of immediate group interests for universal social justice. Otherwise power politics pure and simple would result .

但前提依然是不能让即时利益取代社会的普遍正义，否则就是纯粹的强权政治了。

If a substitution becomes necessary during a group phase, the results of games already played by the substituted player continue to count.

如果在小组赛时不得不替换，那么之前选手已经进行的比赛结果还是有效的。

Using PBS for substitution in c-2 group.

对照组-1：同法注射同体积PBS液。

The influence of the electron structure of the center metal, the type of the substituent group, and substitution position on the photo-generation of 1O2 by the metallophthalocyanines were discussed.

讨论了中心金属电子结构、取代基类型及取代位置对酞菁金属配合物光敏产生1O2能力的影啊。

In this technology the polysaccharide sulfate product having excellent bioactivity is produced with the cotton abounding in the nature as the raw material and through simple chemical reaction. The size and degree of sulfate group substitution of the produced polysaccharide sulfate ester are controllable.

本技术直接利用自然界大量存在的棉花，经简单的化学反应制备具有优良生物学活性的多糖硫酸酯，制备的多糖硫酸酯分子大小可控制、硫酸基团的取代度可控制。

Axial group, substitution on the aromatic rings of SalenAlX, and co-catalyst all affect catalytic properties of these aluminum complexes.

设计合成了一系列四齿席夫碱铝配合物，它们可以溶解在超临界CO〓／环氧乙烷混合物中，是CO〓和环氧烷烃环加成反应的有效催化剂。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。