It requires a second fusion to refine it completely by freeing it from its last earthly impurities . 必须经过第二次熔解，除去最后的矿渣，才能提炼干净。
In order to test the telescope for impurity and scratches, we will reverse it and view the bright sky . 为鉴定望远镜是否不纯净或有划痕，可将其倒着看明亮的天空。
When a donor or an acceptor impurity is added to a semiconductor, we say that the material has been "doped" . 当半导体中加入了施主感受主杂质，我们就说该物质“掺杂”了。
Organic impurities are sometimes present to such an extent that the rock must be calcined to remove them . 有时候矿石中存在有机杂质甚多，以至必须将矿石进行煅烧以消除之。
The impurity of supposedly pure subcellular fractions is a constant threat to the plant biochemist . 以为亚细胞组分很纯而实际不纯的情况，一直是植物化学家感到难办的问题。
To this day coal is said to be screened in the colliery when it has stone and other impurities removed from it . 据说煤中掺有石子和其它杂质须去掉时，至今仍得把煤在矿上筛过。
The solvent, in this case water, is passed through the membrane while the impurities are collected at the membrane's surface . 这样，便使水通过半透膜，而杂质则聚集在膜的表面上。
Since the buildup of impurities often results in defective plating such as discoloration or loss of corrosion resistance . 因为杂质的积累经常导致不良的电镀，如脱色或丧失防腐性能。
Impurities that promote deterioration of polymers can be foreign materials, such as residues from polymerization catalysts . 促使聚合物劣化的杂质可能是外加的物质，如残存的聚合用催化剂。
