照片上各组织间的密度差异称为() A.组织对比度 B.胶片对比度 C.照片对比度 D

题型:单项选择题 A1/A2型题

问题:

照片上各组织间的密度差异称为()

A.组织对比度

B.胶片对比度

C.照片对比度

D.物体对比度

E.X线对比度

考点:放射医学技术(士)医学影像照片处理技术医学影像照片处理技术题库
题型:单项选择题 A1/A2型题

如图所示,矩形区域ABCD内存在着竖直向下的匀强电场,两个带正电的粒子a和b以相同的水平速度射入电场,粒子a由顶点A射入,从BC的中点P射出,粒子b由AB的中点O射入,从顶点C射出。若不计重力,则a和b的比荷(即粒子的电荷量与质量之比)之比是

[ ]

A、1∶2

B、8∶1

C、1∶8

D、4∶1

题型:单项选择题 A1/A2型题

已知等腰三角形的一边等于3,一边等于7,那么它的周长等于(  )

A.13

B.13或17

C.17

D.14或17

题型:单项选择题 A1/A2型题
Do you find getting up in the morning so difficult that it's painful? This might be called laziness, but Dr. Kleitman has a new explanation. He has proved that everyone has a daily energy cycle.         
During the hours when you labor through your work you may say that you're “hot”. That's true. The time of day when you feel most energetic is when your cycle of body temperature is at its peak(高峰). For some people the peak comes before noon. For others it comes in the afternoon or evening. No one has discovered why this is so, but it leads to such familiar monologues ( 自言自语 ) as: “Get up, John! You'll be late for work again!” The possible explanation to the trouble is that John is at his temperature-and- energy peak in the evening. Much family quarrelling ends when husbands and wives realize what these energy cycles mean, and which cycle each member of the family has.
You can't change your energy cycle, but you can learn to make your life fit it better. Habit can help, Dr. Kleitman believes. Maybe you're sleepy in the evening but feel you must stay up late anyway. Counteract ( 对抗 ) your cycle to some extent by habitually staying up later than you want to. If your energy is low in the morning but you have an important job to do early in the day, rise before your usual hour. This won't change your cycle, but you'll get up steam ( 鼓起干劲 ) and work better at your low point.
Get off to a slow start which saves your energy. Get up with a leisurely yawn and stretch. Sit on the edge of the bed a minute before putting your feet on the floor. Avoid the troublesome search for clean clothes by laying them out the night before. Whenever possible, do routine work in the afternoon and save tasks requiring more energy or concentration for your sharper hours.
小题1:If a person finds getting up early a problem, most probably________.
A.he is a lazy person
B.he refuses to follow his own energy cycle
C.he is not sure when his energy is low
D.he is at his peak in the afternoon or evening
小题2:Which of the following may lead to family quarrels according to the passage?
A.Unawareness of energy cycles.B.Familiar monologues.
C.A change in a family member's energy cycle.
D.Attempts to control the energy cycle of other family members.
小题3:. If one wants to work more efficiently at his low point in the morning, he should________.
A.change his energy cycleB.overcome his laziness
C.get up earlier than usualD.go to bed earlier
小题4:Which of the following statements is NOT true?
A.Getting off to work with a minimum effort helps save one's energy.
B.Dr. Kleitman explains why people reach their peaks at different hours of day.
C.Habits help a person adapt to his own energy cycle.
D.Children have energy cycles, too.
题型:单项选择题 A1/A2型题

劳动者和用人单位经过充分协商之后,可以自由约定劳动合同的单方解除条件。

题型:单项选择题 A1/A2型题

下列哪一项与乳痈关系最密切()

A.是 * * 深部的化脓性感染

B.以中年妇女多见

C.初期宜疏肝清热,通乳消肿

D.多由于火毒外侵,以及肝、胃二经湿热蕴结 * * 而成

E.宜节饮食,息恼怒,避免乳岩之变

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