问题 问答题

防止汽轮机超速事故的措施。

答案

参考答案:

(1)坚持调速系统静态试验,保证速度变动率和迟缓率符合规定。

(2)对新安装机组及对调速系统进行技术改造后的机组均应进行调速系统动态特性试验,并保证甩负荷后飞升转速不超过规定值,能保持空负荷运行。

(3)机组大修后,甩负荷试验前,危急保安器解体后都应做超速试验。

(4)汽轮机各项保护符合要求并投入运行。

(5)各主汽门、调速汽门开关灵活,严密性试验合格,发现缺陷及时处理。

(6)定期进行主汽门、调速汽门、各抽汽逆止门活动试验。

(7)定期进行油质分析化验。

(8)加强蒸汽品质监督,防止门杆结垢。

(9)发现机组超速立即破坏真空紧急停机。

(10)采用滑压运行的机组,在滑参数启动的过程中,调速汽门开度要留有裕度。

(11)机组长期停用做好保养工作。

阅读理解

Some students get so nervous before a test, they do poorly even if they know the material. Sian Beilock has studied these highly anxious test-takers.

Sian Beilock: “They start worrying about the consequences. They might even start worrying about whether this exam is going to prevent them from getting into the college they want. And when we worry, it actually uses up attention and memory resources.I talk about it as your cognitive horsepower that you could otherwise be using to focus on the exam.”

Professor Beilock and another researcher, Gerardo Ramirez, have developed a possible solution. Just before an exam, highly anxious test-takers spend ten minutes writing about their worries about the test.

Sian Beilock: “what we think happens is when students put it down on paper , they think about the worst that could happen and they reappraise the situation. They might realize it’s not as had as they might think it was before and, in essence(本质上), it prevents these thoughts from popping up when they’re actually taking a test.”

The researchers tested the idea on a group of twenty anxious college students. They gave them two short math tests. After the first one, they asked the students to either sit quietly or write about their feelings about the upcoming second test.

The researchers added to the pressure. They told the students that those who did well on the second test would get money. They also told them that their performance would affect other students as part of a team effort.

Professor Beilock says those who sat quietly scored an average of twelve percent worse on the second test. But the students who had written about their fears improved their performance by an average of five percent.

Next, the researchers used younger students in a biology class. They told them before final exams either to write about their feelings or to think about things unrelated to the test.

Prefessor Beilock says highly anxious students who did the writing got an average grade of B+, compared to a B- for those who did not.

Sian Beilock: “What we showed is that for students who are highly test-anxious, who’d done our writing intervention, all of a sudden there was no relationship between test anxiety and performance. Those students most likely to worry were performing just as well as their classmates who don’t normally get nervous in these testing situations.”

But what if students do not have a chance to write about their fears immediately before an exam or presentation? Professor Beilock says students can try it themselves at home or in the library and still improve their performance. 

小题1:What may happen if students have the problem of test anxiety?

A.Test anxiety can improve students’ performance to some degree.

B.Students’ attention and memory resources run out when worried.

C.Students may not be admitted into their favorite college if worried

D.Test anxiety is sure to cause students to fail the test.小题2:Which of the following if TRUE?

A.In the first math test, students who sat quietly performed better.

B.In the second math test, students who wrote about their feelings did worse.

C.Some college students are highly anxious test-takers while others are not in the tests.

D.The result in the math test agrees with that in the biology test.小题3:What does the underlined phrase “popping up” mean?

A.Giving out

B.Fading away

C.Becoming clearly

D.Appearing suddenly小题4:what is most probably Sian Beilock?

A.A psychology professor.

B.A philosophy researcher.

C.A politics professor

D.A tutor小题5:What is the main idea of the passage?

A.It is a common practice for students being worried before a test.

B.Being worried before tests does harm to students’ performance.

C.Anxious students overcome test anxiety by writing down fears.

D.It is important for students to overcome test anxiety.

判断题