问题 问答题 简答题

空气流速对无菌空气的制取有何重要意义?

答案

参考答案:

空气流速与除菌效率有密切关系。在微小的流速时,效率随流速的增加而下降,但在某一临界值(约为0.2-0.4米/秒)后,效率随流速的增加而迅速增加,因此经过过滤器的空气流速是一个很关键的变数。它的阻力、效率、过滤器直径及高度有密切关系。一般在设计过滤器时以临界点流速为依据,而实际使用时可采取较高的流速。

阅读理解

Taking good notes is a time-saving skill that will help you to become a better student in several ways .小题1:  Second, your notes are excellent materials to refer to when you are studying for a test. Third, note-taking offers variety to your study time and helps you to hold your interest.

You will want to take notes during classroom discussions and while reading a textbook or doing research for a report.    小题2:   Whenever or however you take notes, keep in mind that note-taking is a selective process.    小题3: 

The following methods may work best for you.

●Read the text quickly to find the main facts and ideas in it.

●Carefully read the text and watch for words that can show main points and  supporting facts.

● Write your notes in your own words.

   小题4:   

● Note any questions or ideas you may have about what was said or written. As you take notes, you may want to use your own shorthand(速记). When you do, be sure that you understand your symbols and that you use them  all the time.  小题5:

A.Use words, not complete sentences.

B.There are three practical note-taking methods.

C.You must write your notes on separate paper.

D.Otherwise, you may not be able to read your notes later.E. you will also want to develop your own method for taking notes.

F. That means you must first decide what is important enough to include in your notes.

G. First, the simple act of writing something down makes it easier for you to understand and remember it.

单项选择题