In fresh water lake, trace elements belonging to hardacid exist mainly as free ion.
在淡水湖泊中，属于硬酸的元素主要以游离离子存在。
2
In the process of cleaning coffee, do not use hard brush scrub, but also to avoid the use of strong acid, alkali cleaning agent, so as to avoid scratching the surface of damaged coffee cup.
The high collecting strength and good selectivity of T-2K is explained using the theory of hard soft acid base and the theory of frontier molecular orbit.