有关焦点极限分辨率的叙述,错误的是A.X线管焦点小,分辨率大B.焦点上线量分布为单峰

题型:单项选择题

问题:

有关焦点极限分辨率的叙述,错误的是

A.X线管焦点小,分辨率大
B.焦点上线量分布为单峰时,分辨率大
C.焦点上线量分布为双峰时,分辨率大
D.MTF=0时的分辨率为极限分辨率
E.MTF=1.0时的信息传递最高

考点:放射医学技师放射技师基础知识初级放射医学技师基础知识
题型:单项选择题


As a kid, everyone wants to learn how to ride a bike. Here is some advice to_1_ you be on your way.
The bike. Start with a bicycle and it’s small enough for your feet to touch the _2_. If you lose your balance, you can put your feet to the ground _3_.
Training grounds. You need a big place for the first part of your practice. Be sure to wear something to keep _4_.
Keeping your balance. It’s very important to learn how to keep your balance. You may practice this easily. _5_ your bike to the higher place. Sit on the bike seat  _6_both feet on the ground. Lift both feet a few inches to let the bike roll down. If you start to fall, just put your feet on the ground. Try practicing this several times _7_ you get your balance.
Pedaling(踩动). After you get your balance, it’s time to _8_ learning how to pedal. Start by sitting on the bike seat. With your left foot on the ground and your right foot on the pedal, then push _9_ on the pedal. Push off with your left foot. Keep on practicing until you learn it well.
Braking(刹车). Catch them lightly at first, slowly increasing the pressure to get to a full _10_. Remember that braking hard while going fast can cause you fall over.
小题1:
A.holdB.help C.feelD.wish
小题2:
A.treeB.floorC.groundD.bike
小题3:
A.at firstB.at lastC.on time D.at once
小题4:
A.dangerous B.safeC.warm D.cool
小题5:
A.TakeB.Bring C.Give D.Ask
小题6:
A.under B.over C.with D.after
小题7:
A.becauseB.thoughC.until D.after
小题8:
A.startB.keep C.enjoyD.finish
小题9:
A.upB.down C.in D.on
小题10:
A.look B.stopC.beginning D.turn
题型:单项选择题

20世纪60年代初的美苏实力对比状况是: [ ]

A、双方势均力敌

B、战略优势在美国方面

C、战略优势在苏联方面

D、苏联军事实力刚刚赶上美国

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下列标志不正确的是 [ ]

A. 当心爆炸

B. 回收标志

C. 节水标志

D. 禁止吸烟

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如图所示正弦交流电路a、b两端的等效复阻抗为()Ω。

A.5

B.20

C.30

D.10

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吗啡结构中手性碳原子个数是()

A.1个

B.2个

C.3个

D.4个

E.5个

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