已知组分 meaning in English

known component

The results showed that the estimation of the dead time and the retention times of the normal alkanes and the further prediction of the retention indices of unknown components were quite satisfactory when the number of the known components included in calculation was not too small
结果显示，在已知组分不是太少的情况下，该方法计算的死时间和正构烷烃的保留时间与实验值吻合，预测的保留指数也有较高的精度。
Abstract ： in order to obtain the retention indices of unknown components in gas chromatography , a method using retention indices and retention times of known components to calculate the dead time and retention times of the corresponding normal alkanes was developed
摘要：提出在部分组分已知的气相色谱灰色体系中，利用已知组分的保留指数和保留时间推算死时间和正构烷烃的保留时间，再计算未知组分保留时间的方法。