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ppm是英文parts permillion的縮寫,譯意是每百萬分中的一部分,即表示百萬分之(幾),或稱百萬分率.如1ppm即一百萬千克的溶液中含有1千克溶質.ppm與百分率(%)所表示的內容一樣,只是它的比例數比百分率大而已.在花卉...
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