有效氧 meaning in Chinese

active oxygen
available oxygen

Method for determination of active oxygen content in manganese ores
锰矿石中有效氧量的测定
Methods of test for boric acid , boric oxide , disodium tetraborates , sodium perborates and crude sodium borates for industrial use - determination of sodium oxide , boric oxide and available oxygen contents of hydrated sodium perborates
工业用硼酸氧化硼四硼酸二钠高硼酸钠与粗硼酸钠的试验方法.水合过硼酸钠中氧化钠氧化硼和有效氧含量的测定