先质

强化絮凝法去除水中DBP先质研究

DBP 's precursor removal by enhanced coagulation in water purification process

通过计算得到了沥青质脱硫饱和烃及其环状生标的参数，这些参数与原油饱和烃的相应参数比较接近，这表明沥青质中的含硫结构单元可能是原油饱和烃的先质。

The parameters of biomarkers in the products are similar to those of saturated hydrocarbon in crude oil , which indicates that these organic sulphur compounds in asphaltene may be the precursor of hydrocarbons .

具体说来，北方文化的最高理念是先质而后文。

To be specific , the supreme concept of the north culture is that " material is prior to culture " .

用精选法求布尔函数的最小化解时，传统的作法是先求出质覆盖Z，然后从Z中挑选必要质蕴涵项。

In minimizing a boolean function using the extraction method , the traditional steps are : getting the prime cover Z first ; and then extracting the essential prime implicant from Z.