吹扫和置换煤气设施内部的煤气,最可靠的介质是()。
A、氮气
B、氢气
C、空气
参考答案:A
It’s very important for a student to ___ a good state of mind while taking the college entrance examination.
A keep out B keep on C keep up D keep off
FID检测器作为质量型检测器,对检测器的温度并不敏感,但是色谱仪()等处的温度设定值,还是对FID有一定的间接影响。
A.进样口
B.柱箱
C.检测器
D.阀箱