quality concentration的用法和样例：
例句
- The difference between par-ticle mass concentration and Bosch smoke number is indicated.
指出微粒的质量浓度与波许烟度的不同。 - The alkalescent condition reduces the mass concentration of iron ions and fastens the nitration reaction of ammonia nitrogen, and leads to the concentration of nitrate.
偏碱性条件使铁离子质量浓度降低，同时促进了氨氮硝化反应进行，使矿井水中硝酸盐和亚硝酸盐质量浓度增加。
