单作用

The reaction barrier will be lowered by the substituents that delocalize the unpair electron in p z orbital of the central carbon atom.

R1和R2位置上取代基对α-氢转移反应势垒的影响取决于取代基对过渡态中碳原子的未参与sp2杂化的p z 轨道上单电子的离域作用。

In oxidation of monooxygenase such as ligninase, oxidative demethylation also happened.

在木质素酶等单加氧酶的氧化过程中也伴随着氧化去甲基作用。

Isosorbide mononitrate is an active metabolite of isosorbide dinitrate and exerts qualitatively similar effects.

单硝酸异山梨酯是二硝酸异山梨酯的一种活性分解物，并表现出同样相似的作用。

This dissertation is mainly focused on the reactivity of methylenecyclopropanes and comprises six parts. 1 The reactions of methylenecyclopropanes with phenylsulfenyl chloride, phenylselenyl chloride and diphenyl diselenide; 2 The coupling reactions of the ring-opening products derivated from methylenecyclopropanes; 3 The palladium-catalyzed ring-enlargement of mono-aryl group substituted methylenecyclopropanes to cyclobutenes. 4 The gold-catalyzed domino ring-opening and ring-closing hydroamination of methylenecyclopropanes with sulfonamides; 5 The Lewis acid-catalyzed reactions of mono-aryl group substituted methylenecyclopropanes with diethyl ketomalonate in the presence of water; 6 The iodobenzene diacetate mediated novel 1,3-dipolar cycloaddition of methylenecyclopropanes, vinylidenecyclopropanes, and methylenecyclobutane with phthalhydrazine.

本论文主要研究了亚甲基环丙烷类化合物的一些化学反应性能，共由以下六部分组成：1、亚甲基环丙烷类化合物与苯硫氯、苯硒氯及二苯基二硒的反应；2、亚甲基环丙烷类化合物开环产物的偶联反应；3、单芳基取代的亚甲基环丙烷类化合物在钯催化剂作用下的扩环反应；4、金化合物催化磺酰胺对亚甲基环丙烷类化合物的串联开环关环氨氢化反应；5、路易斯酸催化亚甲基环丙烷类化合物与丙酮二羧酸二乙酯在有水存在下的反应；6、醋酸碘苯促进的亚甲基环丙烷类化合物、亚乙烯基环丙烷类化合物及亚甲基环丁烷类化合物与邻苯二甲酰肼的新型1，3-偶极环加成反应。

At the same time, during the process of Pu'er Tea, macromolecular polysaccharide transforms into a great deal of new dissoluble monosaccharide and oligosaccharide.

同时，普洱茶在加工过程中，大分子多糖类物质转化成了大量新的可溶性单糖和寡糖，维生素C成倍增加，这些物质对提高人体免疫系统的功能发挥着重要作用，起到了养生健体、延年益寿的功效。

The difference of concordance between monozygotic and dizygotic twins suggested that the susceptibility of MS was affected by genetic factors.

单卵双生子与异卵双生子的患病一致性差异表明，遗传因素在MS发病中起一定作用。

Objective: It was the aim of this study to assess the role of birth weight in the development of myopia using a large cohort of Caucasian monozygotic and dizygotic twins that took part in the Genes in Myopia twin study.

目的：近视眼基因双生子研究通过大样本的高加索人种单卵和双卵双胞胎对出生体重在近视发生中的作用进行评估。

While the effect of IGF on the ovaries likely involves fraternal, or dizygotic, twins, they were not distinguished from identical, or monozygotic, pregnancies in this study.

在本研究中，虽然IGF作用于卵巢可以引起异卵或双合子双胞胎妊娠，但是这种妊娠不能和同卵或单合子双胞胎妊娠相区别。

The results showed:①the communities that stipa baicalensis is edificator had the highest species diversity, and the idea that stipa baicalensis communities were the local zone vegetation was supported;②the majority of studied communities were unsaturated in the species diversity, and the species diversity had a tendency to increate with the improvement of soil environment;③the relation of species diversity to community productivity was a one-humped function, that is, the species diversity of mediation productivity was highest;④the species diversity under intermediate disturbance was highest, and the intermediate disturbance hypothesis was supported;⑤the content of potassium in soil had probably an important function, or was an important following factor in the types of grassland community;⑥a new hypothesis on the forming mechanism of species diversity of community, Small Scale Competition and Random-Patch Dynamic Hypothesis, was put forward boldly.

通过上述研究分析得出如下结果：①以贝加尔针茅为建群种的群落物种多样性最高，从物种多样性角度证明该群落类型最适应本区气候和环境条件，应是本区的地带性群落；②绝大多数群落的物种多样性处于未饱和状态，随土壤环境的改善呈明显的增加趋势；③物种多样性与群落生产力呈单峰函数关系，即在中等生产力水平时物种多样性最高；④放牧中等干扰水平物种多样性最高，支持Connell的中度干扰学说；⑤偶然发现土壤钾含量可能在草地植被类型分化中起到重要作用，至少是一个重要的伴随因子；⑥大胆提出了群落物种多样性构成机制的新学说即小尺度竞争随机斑块动态学说。

In the study of extraction of antimicrobial substance from Eleocharis tuberose peel with ultrasonic, on the basis of single factors test and orthogonal test, the optimal technological parameters were material 60 mesh, ethanol 65%,1:10 for ratio of material to liquid, 45min for ultrasonic time, extraction for one time.

超声波法提取荸荠皮中抑菌物质的实验中，通过单因素及正交实验确定的最佳工艺条件为：采用60目的荸荠皮粉碎物、浓度65％的乙醇溶液、料液比1∶10、超声波作用45min、提取次数一次，在此条件下提取物对大肠杆菌和金黄色葡萄球菌的抑菌圈直径分别为13.3mm和14.3mm。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。