查询词典 absence

In chapter three,we investigated a new Baylis-Hillman-type reaction,organozinc speciesCF_3COOZnEt can react withα,β-acetylenic ketones and N-tosylated imines providing Baylis-Hillman adducts in good yield in the absence of any catalysts.

有机锌试剂CF_3COOZnEt可以与各种类型的α，β-炔酮及亚胺发生偶联反应，高产率的得到β-取代的Morita-Baylis-Hillman反应加合物，这类反应不需要任何的催化剂，产物具有立体单一型，完全是Z式结构。

Organozinc reagents can react with a variety of α,β-acetylenic ketones and aldehydes in the absence of any catalyst. The one-pot reaction affords β-branched Baylis-Hillman type adducts, the multifunctionalized alkenes, in excellent yields with high stereoselectivity.

这种顺式亲核加成反应的发生是由于该类有机锌试剂既具有较强的亲核性，又具有Lewis酸的特性，使有机锌中R基团从同位进攻中心碳原子而形成新的碳碳键。

Their relations were vinegar, although Mr. A when speaking of Mr. B in his absence was acidly correct.

他们之间的关系挺别扭，虽然A先生在背后说起B先生是语中带刺而还不失分寸。

Firstly, it is found that there are many obvious differences between Acorus and Araceae. Their differences are based on many aspects which include characteristics of morphology, anatomy and epidermis of leaf, types of tapetum in anther walls , patterns of endothecial thickenings, and ways of development of endosperms, presence or absence of perisperm, components of photochemistry, and sequences of rbcL.

研究表明：1。菖蒲属与天南星科其它属在叶的形态、结构、表面特征，花药绒毡层类型，药室内壁增厚的特点，胚乳的发育方式，外胚乳的有无，植物化学成分，rbcL基因序列等多方面存在着显著的差异。

Microtopography of diaspore was investigated using atomic force microscope and scanning electron microscope. AFM was used as well to measure the adhesional energy per area and surface force on the diaspore surface in the absence and presence of collector.

采用扫描电子显微镜和原子力显微镜分析了一水硬铝石的表面形貌，并利用原子力显微镜对捕收剂作用前后一水硬铝石的单位面积粘附能进行了定量分析。

The atomic force microscope was used to measure the adhesional energy per area and surface force on the diaspore interface in the absence and presence of collector .

矿物晶体底面（001）层间静电能的大小决定其层面润湿性，其大小关系为：高岭石≥伊利石＞叶蜡石。

In character recognition,the in advertent absence of in k with in a character outl in e.

在字符识别中，字符笔划内无意产生的缺乏墨水的空白点。

No chances Chelsea have started smoothly, playing a careful passing game on a good pitch in the absence of Drogba to hit aerially.

n c 20分–苦无机会：切尔西开局蛮顺利，缺少德罗巴作高空攻击下在不错的草皮上小心奕奕地传球。

It was original report to find the developmental delay of the ENS, absence of submucosal plexus and the aganglionic segment of colon ending in trisomy 16 mice, an animal model for Down syndrome.

Down综合征的动物模型常染色体16三体胎鼠ENS发育迟缓，粘膜下神经丛发育障碍出现后肠末端无神经节区。

Among the more commonly identified impairments and malfunctions of taste are ageusia ,(or ageustia from geustos, Greek for "tasting"), the absence of taste; hypogeusia , dulled or diminished taste; hypergeusia , increased sensitivity to taste; and phantogeusia, the perception of specific tastes—sweet, sour, salty, metallic, or otherwise unpleasant tastes—without the presence of any oral stimulus.

包括在这些更普遍确定的味觉损伤和障碍中的有：味觉丧失(or ageustia from geustos， Greek for &tasting&)，味觉缺失，味觉减退，味觉迟钝或降低，过敏，味觉感受的增加，还有幻味觉，不存在任何的口头刺激下产生细节味觉的感知—甜，酸，咸，金属味或其他的讨厌的味道。

The work of this paper is as follows: 1. Looking back the progressing history of the linear motor, introducing the features of the elevator driven by linear induction motor, radicating the topic of this paper "the digital frequency variable control of the elevator bi-side direct driven by linear induction motor". The research of this paper covers the conventional VVVF control, space vector based VVVF control, vector control and DTC.

本文主要开展了以下几个方面的工作： 1 回顾了直线电机发展历史，电机的驱动技术演变，特别是针对直线电机的驱动，简要介绍了直线感应电机驱动电梯的优点和不同结构类型，对传统的v／f控制，基于空间矢量法的v／f控制，矢量控制，和基于电压空间矢量的直接转矩控制进行了比较，确立了本课题的研究主题：直线感应电机双边直推式驱动电梯的全数字变频控制。

The article combines with the treatment of a superficial civil air defense work to introduce how the grouting method to improve the performance of the backfill soil.

文章从治理漂浮人防工事的角度提出了注浆技术在改善回填土性质方面的应用，并详细阐述了注浆技术的施工流程。