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Kev siv cov khoom lim dej ntawm cov kua
Cov kua lim dej yog ua kom cov kua uas muaj impurities ntws los ntawm cov lim nruab nrab nrog ib qho porosity, thiab cov impurities hauv cov kua yog daig rau saum npoo los yog hauv nruab nrab thiab tshem tawm.Cov kua lim dej muaj xws li cov khoom hauv qab no: dej, ...Nyeem ntxiv
