【名词】1. 集中 2. 【化学】浓缩；浓度；稠密度【矿物】汰选，选矿，富化 3. 集中注意，专心
1. increase in strength by evaporation. 2. the ratio of the mass or volume of a solute to the mass or volume of the solution or solvent. 3. intense mental focus. hydrogen ion concentration see hydrogen ion concentration. mass concentration the mass of a constituent substance divided by the volume of the mixture, as milligrams per liter (mg/l).