5.Filter bed should be exposurd as less as possible because alternation of exposure and immersion is disbennifit to the penetrability of filter bed.
依据水质资料分析了水源水质安全保障。
6.Plastics -- Methods for determining the density of non-cellular plastics -- Part 1: Immersion method, liquid pyknometer method and titration method
塑料.非泡沫塑料的密度测定方法.第一部分:浸渍法、液体比重瓶法和滴定法.
7.Unlike traditional latex or acrylic coatings, polyurea, as a suitable waterproofer even under seawater immersion, is in no way influenced by ponding water, which is very often on existing roofs.