double bond

1. But once you have a double bond here, we have our pi bond, as well as our sigma bond.
   但一旦你有了双键，我们有π键，也有sigma键。
2. The Alkene Double Bond: A Focus of Reactivity.
   烯烃的双键：重点是反应活性。
3. So if we look at its length, it's actually shorter than a single bond, but longer than a double bond.
   因此如果我们看它的键长的话，它实际上比单键更短，却比双键更长。
4. Olefin ( or alkene) Any unsaturated hydrocarbon containing one or more pairs of carbon atoms linked by a double bond ( see covalent bond, saturation).
   含有一对或多对由双键连接的碳原子的一类不饱和烃。
5. And we find the same thing for these two atoms here, it's not actually a double bond, it's somewhere between a single bond and a double bond.
   而且我们发现这两个原子的情况是一样的，它其实不是一个双键，而是介于单键与双键之间的。
6. Theoretical Study of Hydrogen Bonds and Dihydrongen Bonds between π-conjugate Hetero-cyclic Molecules and Some Proton Donors One atom of oxygen is linked to the nitrogen atom by a double bond.
   杂环芳香体系分子间氢键和双氢键的理论研究一个氧原子以双键与氮原子相连。
7. So in order to rotate a double bond, you have to actually break the pi bond, so essentially what you're doing is breaking the double bond.
   为了能够旋转双键，你必须打破一个π键，本质上我们要做的就是打破双键。
8. All right, so let's think of a more complicated example of having a double bond, and maybe a more interesting example, and this is talking about benzene.
   好了，让我们来看关于双键的，一个更复杂的例子，也许是更有趣的例子，我们要讨论苯环。
9. One atom of oxygen is linked to the nitrogen atom by a double bond.
   一个氧原子以双键与氮原子相连。
10. In this case we have a double bond between a and b, and in this case we have it between b and c.
    在这种情况下，我们在，A，与，B，之间有一个双键，而在这种情况下，双键在，B，与，C，之间。
11. In the ethyne molecule, a double bond links together the two carbon atoms.
    在乙烯分子中是由一个双键将两个碳原子连结在一起的。
12. So let's take a look at what actually happens if we're talking about a carbon-carbon double bond, we're going to have a double bond.
    让我们来看一看碳碳双键的情况，例如在乙烷里，我们有个双键。
13. And something that we'll see later on is that triple bonds, for example, are going to be stronger than a corresponding double bond or a corresponding single bond.
    而我们以后还会看到三键，举例来说，应该更强，相较于相应的双键，或者相应的单键来说。
14. The triple bond does not usually react so vigorously at a carbon-carbon double bond.
    三键在反应时一般不象烯烃中的碳-碳双键那样剧烈。
15. NMR characterization of the synthesized products shows that the double bond in the norbornene rig of the product polymers is not affected by the ATRP conducted.
    产物的NMR分析证明所合成产物分子中降冰片烯环上双键未参与聚合反应。
16. Finally, over the course of an hour or so, oxygen from the surrounding environment attacks a bond in the tyrosine, forming a new double bond and creating the fluorescent chromophore.
    最后，大概一小时左右，周围环境里的氧气与酪氨酸反应（攻击一个键），产生一个新的双键，生成荧光团。
17. So really, you can not ever rotate a double bond, it makes your molecule very rigid.
    实际上，你不能转动一个双键，它使得你的分子很坚固。
18. It's a1 and1/ 2 because it's halfway between a double bond and a single bond.
    是因为它介于，单键和双键中间。
19. Moreover, this potential nonwoven technology is claimed to double bond webs depending on mechanical entanglement and heat-fusible function.
    蒸汽加固技术是一种依靠机械缠结力和热熔粘结作用双重加固的新型非织造技术。
20. So it's very important to be keeping in mind that any time you see a double bond, you have a pi bond there, so you're not going to see any rotation around the bond axis.
    所以你们要记住，任何时候你们看到一个双键，这里面有π键，你们不会看到关于键轴的任何转动。
21. So it's very important that the double bond locks it in a particular conformation.
    所以双键把它们锁定在某一特定形状，是十分重要的。
22. And by that what we mean is that they're absolutely identical, and it turns out that this here is not a double bond, it's not a single bond either, it's actually something in between.
    这意味着它们是绝对完全相同的，实际情况应该是这不是一个双键，这也不是一个单键，而是介于两者之间的状态。
23. Introducing electron-withdrawing groups, such as carboxylic ester groups, compensate part of negative shift of the reduction wave due to the effect of the saturation of a fullerene double bond.
    引入具有拉电子性质的基团，如羧酸酯基，则会部分抵消由于C60共扼结构被破坏而引起的电位负移，结果使得电位负移值减少。
24. They react by adding other chemical agents at the double bond to form derivatives or polymers.
    这些化合物的最大用途在于双键与其它化学物质的反应。
25. The author approaches reactivity of double bond α-H from electron effect and frontier orbital theory.
    笔者从电子效应和前线轨道理讨论了双键α-H的反应性。
26. "One-pot" carbon-carbon double bond formation.
    一锅法的碳-碳双键形成反应。
27. The double bond of cyclopentenyl on Cp with HBr, halogen underwent normal electrophilic addition reaction.
    茂环上环戊烯基的双键与HBr和卤素发生正常的亲电加成反应。
28. The double bond residue was obtained by the use of FTIR.
    用FTIR证实了剩余双键。
29. It is important to construct carbon-carbon double bond skeleton in the organic synthesis using Ramberg-B?
    碳碳双键广泛地存在于功能有机分子中，其构筑在合成化学中具有极其重要的意义.Ramberg-B？

noun

1. a covalent bond in which two pairs of electrons are shared between two atoms