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- eighteen membered ring 十八元环
- 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。
- Malmqvist is the sole sinologist among the eighteen members of the Swedish Academy. 马悦然是瑞典皇家学院十八位院士中唯一的汉学家。
- 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。
- The 63th UN Meeting was held on May 12th to reelect the eighteen members of Human Right Concil, and 191 UN members attended and voted. 新华网联合国5月12日电(记者顾震球白洁)第63届联合国大会12日举行会议，改选联合国人权理事会18个成员国，191个联合国会员国的代表出席并投票。
- Men and women of eighteen and above are eligible to vote. 年龄在十八岁以上的男女有投票表决权。
- She dolled herself up as though she was a girl of eighteen. 她打扮得花枝招展，好像是个十八岁的姑娘似的。
- eight member ring heterocyclic compound 八元杂环化合物
- The age of majority is eighteen. 成年的法定年龄是18岁。
- nine member ring heterocyclic compound 九元杂环化合物
- four member ring heterocyclic compound 四元杂环化合物
- The champion is leading by eighteen seconds. 该冠军领先十八秒。
- three member ring heterocyclic compound 三元杂环化合物
- I was eighteen on my last birthday. 我已经过了18周岁了。
- There are eighteen students in that classroom. 那教室里有十八个学生。
- 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。
- In most countries men are called up at the age of eighteen. 在大多数国家，男人在18岁应征入伍。
- Carbocyclic Compounds three-and four membered rings 碳环化合物三元环和四元环
