A.小于0.5PPM B.小于0.1PPM C.小于1PPM D.小于0.7PPM
A.N2>97%(v%) B.N2>98%(v%) C.N2>98.9%(v%) D.N2>99.9%(v%)
A.≤2μs/cm(25℃) B.≤0.5μs/cm(25℃) C.≤0.2μs/cm(25℃) D.≤4μs/cm(25℃)