碳环的

"Olefins may be classified by whether the double Bond is in a ring or a chain or by the number of double Bonds (monoolefin, diolefin, etc.)."

有两种分类方法︰一、分为环烯烃和非环烯烃，双键依次位于成环碳原子之间或开链基团的碳原子之间。

In order to meet the requirements of light weights,high specific strength and high specific moduli for a space payload,the advantages and disadvantages of the engineering materials used in the supports of the space payload were analyzed,and the feasibility of the application of the carbon/epoxy composites to the support structures was explored.

为了满足航天有效载荷轻型化、高比强度、高比模量的要求，分析了航天有效载荷支撑结构常用工程材料的优缺点；阐述了碳/环氧复合材料在航天有效载荷承力支撑结构中应用的可行性；介绍了该材料在航天有效载荷中的实际工程应用及相关设计方法。

This showed that the electron density of a quinoid ring increased. The peaks of the quaternary carbon atoms of the benzene rings, which were adjacent to the quinoid ring, also shifted to higher field. But the peaks of other C atoms shifted to lower field.

NMR结果表明苯胺低聚体掺杂后主链上的电荷重新分布，环上的H原子上的电子被C原子吸引，电荷密度降低，在〓 NMR中谱峰向低场移动。C原子的谱峰也相应发生变化，醌环上电荷密度增加，全部C原子的峰向高场移动，与醌环相邻苯环受其影响季碳峰移向高场，非季碳峰移向低场。

During these years (1997-2000) in the research area of annonaceous acetogenins 5 natural products and a number of chiral-pure analogs of annonaceous acetogenins have been synthesized using sugars as the starting materials. Their high activity and selectivity against cell line of colon tumor and a relationship between activity and configuration have been found too. In the respect of inhibitor of sialidase two new methodologies for the synthesis of chiral-pure 3-deoxy-ulosonic acid using hetero-Diels-Alder reaction or asymmetric propargylation as the key reaction were developed. On the topic of anti-leukemia marine natural product clavulactone a synthetic method based on the free radical cyclization and starting from sugar has been developed. In other title of PKC inhibited agent sphingosine a new synthetic route with SN2' as the key reaction has also been disclosed.

项目期间（1997-2000）在番荔枝内酯方面从糖出发合成了五个天然产物和一批手性纯的类似物，它们对肠癌细胞有很高的活性和选择性，并与构型有关；在唾液酸酶抑制剂方面发展了二类全新手性纯高碳糖的合成方法－杂原子D－A反应或丙炔基不对称加成为关键的反应；抗白血病海洋天然产物群柱虫内酯方面研究了由糖出发和自由基环化反应的合成方法；对PKC 起抑制作用的鞘氨醇方面也开创了新的合成途径－由糖出发并以SN2'反应为关键反应。

The influence of environmental variables on distribution of PAHs(1) The concentrations of PAHs were higher in warm temperate zone and subtropical zonethan in low temperature zone;(2) The concentration in plain, hilly land and Ya\'an mountainousregion were higher than in other places;(3) The concentration in paddy fields, dry land andforests were higher than in artificial land and grass;(4) There was positive correlation betweenthe concentration of PAHs and TOC. The correlation was more obvious for 4-rings PAHs thanfor 5-, 6-rings PAHs;(5) The concentration of PAHs in acid soils was higher than in alkali andneutral soils;(6) The concentrations in conifer and spinney forest were higher than inbroad-leaved forest.Part two: The temporal and spatial distribution characteristics of POPs at Basin-MountainTransect.

环境因素对多环芳烃分布的影响(1)温带和亚热带地区土壤多环芳烃含量高于低温地区土壤中多环芳烃含量；(2)在平原、匠陵和雅安市附近的山区多环芳烃含量高于其他地区含量：(3)水田、旱地和林地多环芳烃含量高于建筑用地和草地中含量；(4)多环芳烃含量和土壤总有机碳含量成正比，四环多环芳烃与总有机碳的相关性高于其他多环芳烃的相关性；(5)酸性土壤中多环芳烃含量高于碱性和中性土壤中含量；(6)针叶林和灌木林多环芳烃含量高于阔叶林中的含量。

Also useful are oil-soluble copper dithiocarbamates of the general formula Rc Rd z Cu, where z is 1 or 2, and Rc and Rd are the same or different hydrocarbyl radicals containing from 1 to 18, and preferably 2 to 12, carbon atoms, and including radicals such, for example, as alkyl, alkenyl, aryl, aralkyl, alkaryl and cycloaliphatic radicals.

化学通式为Rc Rd z Cu的油溶性二硫代氨基甲酸铜也适用，式中，z为1或2，Rc和Rd是含1～18（以2～12为宜）个碳原子的相同或不同的烃基，这类烃基的实例包括烷基、烯基、芳基、芳烷基、烷芳基和脂环基。

In conclusion, a catechol moiety is presumably to be essential for its activity and substitution of the p-hydroxybenzyl group at C-1 position with correct stereochemistry in the isoquinoline molecule makes a great contribution to the activation of beta adrenergic receptors.

本实验初步结果发现，对於去甲基乌药碱分子之药效，catechol基是必备无疑；而异喹啉环的碳－1位置上取代的p-hydroxybenzyl基对於药效有非常大的影响；至於其立体化学的配位是有立体选择性的。

Synthesis of organic sulfuric compounds in aqueous media is carried out by: using thio-olefin compounds with carbonyl compounds, acetal/keltone, hydrazone, oxime, osazone and enamine to synthesize mercaptal/keltone compounds in aqueous media; using thio-olefin compounds with alpha-hydroxyaldehyde/keltone or alpha-halogenated aldehyde/keltone to synthesize thia-olefin derivatives in a queous media; using thio-olefin compounds with alpha, beta-unsaturated hydroxy compounds, C-C treble bond, C-N treble bond, C-C double bond, N-N double bond, C-N double bond, C-S double bond, epoxy and its derivatives, aziridine and its derivatives, cyclopropane and its derivatives and halogenated carboxy to synthesize sulfoether compounds in a queous media.

含水介质中有机硫化合物的合成方法，本发明属于有机合成方法，用硫缩烯酮类化合物与羰基化合物、缩醛/酮、腙、肟、脎、烯胺在含水介质中合成缩硫醛/酮化合物，与α-羟基醛/酮或α-卤代醛/酮在含水介质中合成噻烯类衍生物，与α，β-不饱和羰基化合物、碳碳叁键、碳氮叁键、碳碳双键、氮氮双键、碳氮双键、碳硫双键、环氧乙烷及其衍生物、氮杂环丙烷及其衍生物、环丙烷及其衍生物、卤代烃等在含水介质，中合成硫醚化合物。

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。

At present, much attention had been paid to the study of the surfactants with four coordinate boron oxygen heterocycles structure, however, the main work was focused on the synthesis of the surfactants containing boron with short-carbon chain alkyls and their basic properties.

目前研究的方向主要是含四配位硼氧杂环结构的表面活性剂，但都是对一些含短链烷基的合成和基本性质研究，对含长碳链的还极少见文献报道。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。