查询词典 ethylenic

A simple and efficient method for the synthesis of N3-functionalized 3,4-dihydropyrimidinones by aza-Michael addition reactions of 3,4-dihydropyrimidinones toα,β-ethylenic compounds catalyzed by KF/Al_2O_3 is described.

研究结果表明：DHPMs类化合物可与α，β-不饱和羰基化合物发生Michael加成反应，产物只有N3位功能化的DHPMs，而没有N1位的产物。

Experiment results indicate that both the ethylenic derivative of benzophenone and the new synthesized polysiloxane are characteristic of three typical intensive and broad absorption bands in ultraviolet region at about 240nm, 288nm and 326nm, and show effective ultraviolet absorptive ability in wavelengths between 240nm and 400nm.

结果表明：中间体和聚硅氧烷在紫外光区均具有二苯甲酮衍生物特有的三条吸收谱带，对波长240~400nm的紫外光有良好的吸收作用。

The coating composition comprises, in a specific proportion, a vehicle ingredient comprising in a specific proportion an oligomer having at least twoacrylate groups and an ethylenic monomer copolymerizable with the oligomer, aacrylic-modified chlorinated polyolefin having a specific chlorine content, an organic peroxide polymerization initiator, and a polyisocyanate compound.

该涂料组合物含有特定比例的由至少具有两个丙烯酸酯基的低聚物和可与该低聚物共聚的乙烯性不饱和单体形成的媒介物成分、特定氯含率的丙烯酰基改性氯化聚烯烃、有机过氧化物聚合引发剂、和聚异氰酸酯化合物。

In the presence of alkalinity and tetraethyl ammonium bromide, 2,4-dihydroxy benzophenone reacts with allyl glycidyl ether to form an ethylenic derivative of benzophenone, 2-hydroxy-4-(β-hydroxy-γ-allyloxy) propyloxy benzophenone, which can further undergo hydrosilylation with polyhydromethylsiloxane.

在相转移催化剂四乙基溴化按作用下，利用2，4-二羟基二苯甲酮与烯丙基缩水甘油醚在碱性水溶液中的开环加成反应，合成了中间体4-丙氧基－2-羟基二苯甲酮，将其进一步与聚甲基氢硅氧烷进行硅氢化加成反应。

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。