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- The calculated results show that the aza Wittig reaction is a two step reaction, having one four membered ring intermediate on its reaction surface. 计算结果表明该反应是一个二步反应，在反应途径上存在一个四元环中间体。
- Method Treatment of 8,9 anhydroerythromycin 6,9 hemiketal with iodine in the alkaline solution provided corresponding N monodemethylated 12 membered ring erythromycin derivative. 方法8,9脱水红霉素6,9半缩酮与碘在碱性溶剂中反应得到相应的N去甲基十二元环红霉素衍生物。
- A company limited by shares has a Board of director with five to nineteen members. 股份有限公司设董事会,其成员为五人至十九人。
- The characteristic vibrational modes were assigned to the planar six membered ring (B 3O 6) 3- and tetrahedral BO 4. The vibrational spectra of CBO, CLBO, and Lithium triborate (LBO) were compared and the effect of cation was discussed. 然后比较了CBO，CLBO和LBO（LiB3O5）三种晶体的晶格振动光谱，讨论了阳离子对振动光谱的影响。
- eight member ring heterocyclic compound 八元杂环化合物
- nine member ring heterocyclic compound 九元杂环化合物
- They were chatting away nineteen to the dozen. 他们聊个没完。
- four member ring heterocyclic compound 四元杂环化合物
- There are nineteen students in my class. 我班里有十九个学生。
- three member ring heterocyclic compound 三元杂环化合物
- They are chatting away nineteen to the dozen. 他们正在说个不停。
- She had the sapphire set in a gold ring. 她把那枚蓝宝石镶在金戒指上了。
- The diamond ring dazzled with brilliancy. 这只钻石戒指闪耀夺目。
- He was born in the nineties of the nineteen century. 他生于十九世纪九十年代。
- Carbocyclic Compounds three-and four membered rings 碳环化合物三元环和四元环
- She wears a diamond ring on her left hand. 她左手上戴着一枚钻石戒指。
- Our family reunions are always three ring circus. 我家合家团聚的场面总是热闹非凡。
- He is an active member of the school's stamp club. 他是学校集邮俱乐部的一名活跃会员。
- Our club is a member of the Football League. 我们的俱乐部是足球联合会的一员。
- Her tongue goes nineteen to the dozen. 她喋喋不休说个没完。
