问题 问答题 论述题

CRHl供风系统干燥塔的工作原理及工作过程是什么?

答案

参考答案:双塔空气干燥器的再生和干燥工作同时在两个塔内进行,并定时轮流转换工况。当主气流在一个塔室内进行空气干燥处理(吸咐水分)时,干燥剂在另一个塔室内被再生处理(将吸咐的水分排出)。

工作过程如下:来自主压缩机含水分的压缩空气进入空气干燥器时,首先在油水分离器上进行初步过滤,然后空气气流通过含有干燥剂的塔室时,水分被吸咐,使空气干燥器出口处主气流的相对湿度不大于35%,完成干燥工作。同时,干燥后的部分空气从主气流上分流出来,通过再生节流孔进入另一个塔室,在另一个塔室内,气流将干燥剂(干燥剂在前一个干燥阶段吸收了水分,需要再生)内已吸咐饱和的水分排放到车外。在转换装置的作用下,两个塔室每隔2min循环一次,确保两塔轮流完成干燥主气流的作用。

完形填空

Section B (10分)

Directions: Read the following passage. Answer the questions according to the information given in the passage and required words limit. Write your answers on your answer sheet.

Now let us look at how we read. When we read a printed text, our eyes move across a page in short, jerky movement. We recognize words usually when our eyes are still when they fixate. Each time they fixate, we see a group of words. This is known as the recognition span or the visual span(视幅). The length of time of which the eyes stop ---the duration of the fixation ----varies considerably from person to person. It also varies within any one person according to his purpose in reading and his familiarity with the text. Furthermore, it can be affected by such factors as lighting and tiredness.

Unfortunately, in the past, many reading improvement courses have concentrated too much on how our eyes move across the printed page. As a result of this misleading emphasis on the purely visual aspects of reading, numerous exercises have been devised to train the eyes to see more words at one fixation. For instance, in some exercises, words are flashed on to a screen for, say, a tenth or a twentieth of a second. One of the exercises has required students to fix their eyes on some central point, taking in the words on either side. Such word patterns are often constructed in the shape of rather steep pyramids so the reader takes in more and more words at each successive fixation. All these exercises are very clever, but it’s one thing to improve a person’s ability to see words and quite another thing to improve his ability to read a text efficiently. Reading requires the ability to understand the relationship between words. Consequently, for these reasons, many experts have now begun to question the usefulness of eye training, especially since any approach which trains a person to read isolated words and phrases would seem unlikely to help him in reading a continuous text.

81. Show at least three facts which can affect the time of the recognition span. (no more than 14 words)(2分)

___________________________

82.what does reading require according to the writer?(no more than 8 words)(2分)

________________________

83. What is the attitude of the author towards reading improvement courses mentioned in the passage? ( one word )  (3分)

_______________________

84. What will probably the writer talk about next? (no more than 12 words)(3分)

_____________________

单项选择题