关于射线在材料中的衰减,下述哪种叙述是正确的?()A、它与材料中的散射强度成正比 B

题型:单项选择题

问题:

关于射线在材料中的衰减,下述哪种叙述是正确的?()

A、它与材料中的散射强度成正比

B、它与射线源的距离平方成正比

C、它随材料的厚度,大致以指数规律变化

D、它与材料的厚度成正比

考点:无损检测技术资格人员考试中级无损检测技术资格人员中级无损检测技术资格人员题库
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人体缺乏某些元素(Ca,Fe.I),就会影响人体健康甚至生病,根据你所学的知识填写下表

人体缺乏的元素症    状
______骨质疏松,畸形,易得佝偻病
______大脖子病
______贫血

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阅读理解。

     14-year-old Jason Morgan talks about an exciting science project.

     Last month I got the chance to take part in an underwater research project in an area of the Gulf of

Mexico called the Flower Gardens. A team of professional researchers' led by the scientist Dr Matt Phillips,

was trying to learn more about the fish and different creatures that live in this part of the sea. The Flower

Gardens are a long way from the shore (海岸) and we spent three days on a boat.

     The team used a piece of underwater equipment called ROV to collect information. The ROV was great fun. It was controlled by a computer on the boat, and I was allowed to operate it a few times. 

     However, the thing I enjoyed most was diving (潜水) into the water. At first, I was quite scared---mainly

because I couldn' t see land in any direction. But as soon as I jumped into the water, I wasn't afraid anymore.

It was amazing to see the colorful fish swimming around and I could see all the ways to the Flower Gardens,

which are almost 30 meters down. I will never forget the Flower Gardens. The trip was like a holiday but I also

learnt new things about science and research projects. It was a great opportunity and it has made me think

about my goals (目标) in life. The experience will help me work harder to become a scientist.

1. Jason and the team stayed on the boat for ______ days.

A. three

B. two

C. five

D. eight

2. What did Jason think of the ROV?

A. It was boring.

B. It was difficult to operate.

C. It was great fun.

D. It was an expensive piece of equipment.

3. Jason didn't ______ in the Flower Gardens.

A. operate the ROV

B. walk along the shore

C. dive in the water

D. see many colorful fish

4. What influence has the trip had on Jason?

A. It has changed his opinion of science.

B. It has improved the way he works in a team.

C. It has made him more interested in the sea.

D. It has encouraged him to work harder towards his goals.

5. What might Jason write in his diary about the trip?

A. It was interesting to work with Dr Phillips and his team but I wish someone else had been on the trip.

B. The Flower Gardens are beautiful but scientists are worried that pollution are worried that pollution.

C. The trip was like a holiday and I saw some amazing fish. The only thing I dislike was

     collecting information about the sea.

D. Going to the Flower Gardens was great fun. I now know much more about science but

     I realize there's still a lot more to learn.

题型:单项选择题

常用的访问顾客的方法有()。

A.面谈

B.电话访问

C.直接访问

D.间接访问

E.信件访问

题型:单项选择题

流行性腮腺炎以()()为主要特征。

题型:单项选择题

扭矩的测定可通过测量轴受扭矩作用后,产生的()大小而()获得测量值。

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