在匀强磁场中有一个原来静止的碳14原子核,它放射出的粒子与反冲核的径迹是两个相内

题型:选择题

问题:

在匀强磁场中有一个原来静止的碳14原子核,它放射出的粒子与反冲核的径迹是两个相内切的圆,如图所示.那么碳14的衰变方程为(  )

A.+

B.+

C.+

D.+

考点:带电粒子在匀强磁场中的运动α衰变β衰变半衰期
题型:选择题

消化性溃疡患者发生夜间痛和背部放射痛最突出的是

A.胃大弯溃疡

B.幽门管溃疡

C.胃小弯溃疡

D.十二指肠球后溃疡

E.食管溃疡

题型:选择题

哪一项是正常妊娠脉象:()

A.滑利而尺脉按之不绝

B.手少阴脉动甚

C.阴搏阳别

D.滑疾流利

E.以上都是

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I was a single parent of four small children, working at a low paid job. Money was always tight, but we had a (1) over our heads, food on the table, clothes on our backs, and if not a lot, always (2) . Not knowing we were poor, my kids just thought I was (3) . I’ve always been glad about that.

It was Christmas time, and although there wasn’t (4) for a lot of gifts, we planned to celebrate with a family party. But the big (5) for the kids was the fun of Christmas (6) .

They planned weeks ahead of time, asking (7) what they wanted for Christmas. Fortunately, I had saved MYM120 for (8) to share by all five of us.

The big (9) arrived. I gave each kid a twenty-dollar bill and (10) them to look for gifts of about four dollars each. Then everyone scattered. We had two hours to shop; then we would (11) back at the "Santa’s Workshop".

Driving home, everyone was in high Christmas spirits, (12) my younger daughter, Ginger, who was unusually (13) . She had only one small, flat bag with a few candies—fiftycent candies! I was so angry, but I didn’t say anything (14) we got home. I called her into my bedroom and closed the door, (15) to be angry again. This is what she told me.

"I was looking (16) thinking of what to buy, and I (17) to read the little cards on the ’Giving Trees’. One was for a little girl, four years old, and all she (18) for Christmas was a doll. So I took the card off the tree and (19) the doll for her. We have so much and she doesn’t have anything. "

I never felt so (20) as I did that day.

14()

A.since 

B.after 

C.while 

D.until

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进程之间相互协调,彼此之间交换信息,这就是进程间的通信。当系统中各进程并发共享资源,从而使系统资源得以充分利用,这往往表现为______。

题型:选择题

什么是水泵特性曲线?

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