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衍射仪测量在入射光束、试样形状、试样吸收以及衍射线记录等方面与德拜法有何不同?

答案

参考答案:

入射X射线的光束:都为单色的特征X射线,都有光栏调节光束。不同:衍射仪法:采用一定发散度的入射线,且聚焦半径随2θ变化,德拜法:通过进光管限制入射线的发散度。试样形状:衍射仪法为平板状,德拜法为细圆柱状。试样吸收:衍射仪法吸收时间短,德拜法吸收时间长,约为10~20h。记录方式:衍射仪法采用计数率仪作图,德拜法采用环带形底片成相,而且它们的强度(I)对(2θ)的分布(I-2θ曲线)也不同。

阅读理解

While I was in 9 th grade, I built a circuit (电路装置) for the traffic system of our city. After getting the first prize. I got this valuable advice from my father; “Do whatever interests you, and don’t let the work challenge you, make sure you are challenging that work.”

I have always preferred the projects which are challenging and related to real life problems. I clearly remember building a shipping program several years ago. I divided the whole project into several small sections. When I understood it clearly, used my brainstorming skill on it, and gave some basic ideas. Then I asked my professor for help before jumping into coding (编码). At first, I did not know how to ask questions correctly and always asked the question “How do I do it?” As I  kept working and discussed with my professor, I became more comfortable and those “how ”questions soon turned into “what if I do this and that” types of questions.

It took me four days to write the code. The desire to solve the problem kept me sleepless all nights brainstorming in even greater details. Every time I saw my program running smoothly, I exploded with joy. I still remember the last day of my work. I was getting some problem and didn’t know what to do. At that moment, a man came in to clean. He has headphones, and he was dancing while cleaning the room. Seeing this, I burst out laughing. That moment calmed me. I regained energy and interest and started to work again, and soon I fixed the problem.

My success in the project proved that breaking up a large problem into small parts could help find a possible solution. Discussing the problem with others was also very beneficial. Now I have gained the confidence to attempt any kind of project.

59.According to the passage, the writer was interested in          .

A.developing traffic systems

B.doing challenging projects

C.winning great prizes

D.writing different codes

60.The writer asked the question “how do I do it” at first because         .

A.he had no clear idea about his program

B.he was too shy to express himself

C.he wanted to he understood easily

D.he preferred this kind of question

61.We learn from the passage that the writer’s shipping program         .

A.would benefit people a lot

B.was done together with others

C.was difficult and needed patience

D.cost much money and energy

62.What would be the best title of the passage?

A.Do It Yourself

B.No Pains, No Gains

C.Learning with interest

D.Practice Makes Perfect

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