问题 单项选择题

对可燃粉尘的生产装置进行惰化防护,即在生产装置中通入惰性气体,使实际氧含量比临界氧含量低()%。

A.20

B.30

C.25

D.15

答案

参考答案:A

解析:

本题考核的是控制粉尘爆炸的技术措施。控制产生粉尘爆炸的主要技术措施是缩小粉尘扩散范围,消除粉尘、控制火源、适当增湿。对于产生可燃粉尘的生产装置,可以进行惰化防护,即在生产装置中通入惰性气体,使实际氧含量比临界氧含量低20%。在通入惰性气体时,必须注意把装置里的气体完全混合均匀。在生产过程中,要对惰性气体的气流、压力或对氧气浓度进行测试,应保证不超过临界氧含量。

阅读理解

阅读理解。

     Science is a major topic in our culture. Since it touches almost every field of our life, educated people

need at least some knowledge with its structure and operation. They should also have an understanding

of the scientific subculture in which scientists live and the kinds of people they are. An understanding of

general characteristics of science as well as specific scientific ideas is easier to obtain if one knows

something about the things that excite and discourage the scientist.

     This book is written for the person whose knowledge with science is not complete; for the person who

has been presented with science as a musty (发霉的) storehouse of dried facts; for the person who sees

the chief objective of science as the production of tricks; and for the person who views the scientists as

some sort of magician. The book can be used to add to a course m any science, to come with any course

that attempts to give an understanding of the modem world, or simply to provide a better understanding of

science. We hope this book will lead readers to a broader view on scientific attitudes and a more realistic

view of what science is, who scientists are, and what they do. It will give them an idea and understanding

of the relationship between science and our culture and an appreciation of the roles science may play in our

culture. Besides, readers may learn to appreciate the relationship between scientific views and some of the

values and philosophies that are deep in our culture.

     We have tried to present in this book a correct and up-to-date picture of the scientific world and the

people who populate it. That population has in recent years come to include more and more women. This

increasing role of women is not just the only event but, rather, part of the trend obvious in all parts of society,

as more women enter traditionally male-controlled fields and make influential contributions.

     We have also tried to make the book entertaining as well as informative. Our method is usually informal.

We feel, as do many other scientists, that we shouldn't take ourselves too seriously. As the reader may

observe, we see science as a delightful pastime rather than a cruel and unpleasant way to earn a living.

1. The passage most probably is ____.

A. the introduction of a book

B. the information added to a book

C. the concluding part of a book

D. the review of a book

2. We need to know something about science because ____.

A. it is easier to understand general characteristics of science

B. scientists have specific scientific ideas

C. it is not easy to understand the things that excite and discourage scientists

D. science affects almost every field of our life

3. The book mentioned in this passage is written for readers who ____.

A. have a misunderstanding about science

B. are scientists making influential contributions

C. want to break the male-controlled world

D. want to have a little understanding of science

4. According to the passage, we can infer that the book probably is ____.

A. serious

B. humorous

C. interesting

D. realistic

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