1.It's disbennifit to become protected film if change the velocity of flow frequently.
频繁改变水的流速不利于在材料表面形成护膜,而护膜于防腐蚀是至关重要的。
2.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障。
3.Our country practices tail system,and takes direct mode of inherit.It is very disbennifit to protect debtee because there is not efficiency supervision to haeres.So it is necessary to restrict haeres.