短语词组短語cetyl trimethyl ammonium bromide precipitation 十六烷基三乙基溴化銨沉澱法cetyl trimethyl ammonium bromide ctab 十六烷基三甲基溴化銨ammonium cetyl trimethyl bromide 溴化十六烷基三甲銨 返回 cetyl trimethyl ammonium bromide