P - methoxybenzeneacetonitrile was prepared in 34.8 % yield starting from anisole, via chloromethylation, cyanogenation and fractional distillation.以苯甲醚为原料,经过氯甲基化, 氰化反应后, 通过精馏获得对甲氧基苯乙腈,总收率为34.8%....
She felt a certain ambivalence towards him.她对他的态度有些矛盾.I've never lied about my feelings, including my ambivalence about getting married again.对于自己的感情，我从来不说谎，包括我对于再婚游移不定的态度。The document expressed some ambivalence ove...
而且, 这一目标或许要早于防止污染.Indeed, this strand may well predate the anti - pollution effort.在世界上大部分地区, 以重量表示价值的金属作为货币使用早于硬币.Metal, valued by weight, preceded coins in many parts of the world.测色学的基本概念早于1853年由格腊斯曼加以阐述.The basic con...
It was feared they could break the Allies' codes.恐怕他们会破译盟军的密码。A generation ago genetic codes were certainly unknown.遗传密码在上一代确实很少有人知道.There are many ancient codes and records in the library of our institute.在我院图书馆里藏有...
放大器自激振荡的频率就取决于流体的速度.Amplifier self - oscillates at a frequency depending on the velocity of the fluid.这种方法适于不均匀流体的测量.This method is suited to the measurement of irregular streams.稳态热流和不可压缩流体的流动可相比拟.Steady - state heat fl...