原子荧光光度计与原子吸收光度计的主要区别是什么?
参考答案:
1.原子荧光仪采用高强度空心阴极灯或无极放电灯等强度更大的光源;
2.光路垂直(避免光源射线进入检测器)。
54. --- I have two suggestions: one is to go to the cinema, the other is to have a drink.
--- Well, personally I prefer the _____ one. I don’t like films very much.
A.late
B.latter
C.latest
D.Last
为了安全起见,钢丝绳必需在卷筒上至少保留二圈以上。()
A、正确
B、错误