化学纯净 meaning in English

chemically pure

In this thesis the preparation of " chemically pure " metal colloids by nd : yag laser ablation of metal plate is introduced . the measurement result of tem of the nanoparticle systems obtained the experiment is reported that the size of these colloids were between 5 to 35nm
2 、论文介绍了一种新的制备金属胶体及纳米量级粗糙金属表面的方法：利用nd : yag激光器1064nm激发光照射金属表面，通过改变光照时间，制备出“化学纯净”纳米金属胶体。