什么是X射线管的阴极特性?
参考答案:
阴极特性即指灯丝的加热温度与灯丝电子发射率的关系。
情景对话。从B栏选出A栏最恰当的答语,并将其序号写在题前括号内。(5分)
A
小题1: I’m not feeling very well.
小题2: Where are you going to work in the future?
小题3: What do you think of the Wanda Cinema?
小题4: I’m going to West Lake on vacation.
小题5: When did she become a movie star?
B
A.Have a good trip!
B.I’ m sorry to hear that.
C.I’m not sure yet. Maybe Dalian.
D.It’s the most expensive one in the city.E. At the age of 17.
中鼻突形成()
A.上唇两侧部分
B.下唇
C.两侧鼻翼
D.上唇人中部分
E.鼻梁和鼻尖