丁基乙烯

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。

As superplasticizer , a series of comb-shaped copolymers of polycarboxylic acid were synthesized by polyoxyethylene allyl methyl diether, maleic anhydride, and styrene with different initiators,and esterified with PEO-n.

以聚氧乙烯甲基烯丙基二醚、顺丁烯二酸酐、苯乙烯等为共聚单体，采用不同引发剂，合成了一系列聚羧酸型梳状共聚物超分散剂，并以PEO n单酯化得酯化产物，研究了共聚物的结构、组成、添加量等对水泥粒子分散性能的影响。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。