【单选题】【消耗次数:1】
减小液压冲击的措施:使直接冲击改变为间接冲击;限制管中油液的流速;用橡胶软管或在冲击源处设置蓄能器;在容易出现液压冲击的地方,安装限制压力升高的溢流阀。该说法( )
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错误
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相关题目
【单选题】 压力冲击是指系统压力突然升高,但溢流阀反应迟钝,不能迅速打开时,便产生压力超调,称之为压力冲击。该说法( )
①  正确
②  错误
【单选题】 液压系统中某些元件的动作不够灵敏,也会产生液压冲击。该说法( )
①  正确
②  错误
【判断题】 在液压系统中,由于某种原因,液体压力在一瞬间会突然升高,产生很高的压力峰值,这种现象称为液压冲击。该说法( )
①  正确
②  错误
【判断题】 液压冲击有时会使一些液压元件或管件损坏,并使某些液压元件产生误动作,导致设备损坏。该说法( )
①  正确
②  错误
【判断题】 液压冲击的压力峰值比正常工作压力高好几倍,且常伴有巨大的振动和噪声,使液压系统产生降温。该说法( )
①  正确
②  错误
【判断题】 搞清液压冲击的本质,估算出它的压力峰值并研究抑制措施,是十分必要的。该说法( )
①  正确
②  错误
【判断题】 液压系统在工作过程中由于外载变化,换向冲击、管道振动等原因,容易使管接头、紧固螺钉松动。该说法( )
①  正确
②  错误
【判断题】 液压冲击的实质主要是管道中的液体因突然停止运动而导致动能向压力能的瞬时转变。该说法( )
①  正确
②  错误
【判断题】 液压系统中运动着的工作部件突然制动或换向时,工作部件的动能将引起液压执行元件的回油腔和管路内的油液产生液压激振,导致液压冲击。该说法( )
①  正确
②  错误
【多选题】 冲击地压的解危措施有( )
①  A.卸载钻孔
②  B.卸载爆破
③  C.诱发爆破
④  D.煤层高压注水
随机题目
【单选题】 5. His father began to work ____he was seven years old.
①  as old as
②  as early as
③  as soon as
④  as much as
【单选题】 13. The house is ____ small for a family of six.
①  much too
②  too much
③  very tall many
④  many very tall
【单选题】 10. It was very hot yesterday, but it is ____today.
①  even hotter
②  more hotter
③  much more hot
④  much hot
【单选题】 12. When we arrived, we found the meeting room crowded with ____ students.
①  quite a few
②  only a few
③  few
④  a few quite
【单选题】 9. These children are ____this year than they were last year.
①  more tall
②  more taller
③  very taller
④  much taller
【单选题】 1. This box is ____that one.
①  heavy than
②  so heavy than
③  heavier as
④  as heavy as
【单选题】 14. Through the window we can see nothing but ____ buildings.
①  tall very many
②  very many tall
③  very tall many
④  many very tall
【简答题】 Thousands of years ago in Egypt (埃及), Kings built the pyramids (金字塔). They used to build them as their tombs (坟墓). The kings thought the pyramids would help them find life [填空1]death. They also wanted the world remember them as important people. Some pyramids were for queens, but they are [填空2]interesting because they are not so big. The[填空3]pyramid that we know today is the pyramid that we know today is the pyramid near Sahara ( 撒哈拉沙漠) in Egypt. It is about 5,000 years old. There are many pyramids along the Nile River (尼罗河). The largest is the pyramid of Khufu (法老胡夫). It is made of two million three hundred thousand huge stones, most of [填空4]higher than a person. It is about 144 meters high. Inside the pyramid[填空5]the burial rooms (墓室)for the king and queen and long passage (通道) ways [填空6]these rooms. The rest of the pyramid is solid (坚固的) stone. We know there were wonderful[填空7]in the pyramid. Robbers[填空8]into the pyramids and took many of these treasures (财宝). Today some of the treasures are in museums [填空9]. How did the people of ancient [填空10]build the pyramids?How did they carry and lift the huge stones? Each stone [填空11]so well and they didn’t have our[填空12]machines. Scientists[填空13]the pyramids but nobody can say just how they [填空14]. Some day if you can, you ought to go to see the pyramids. I[填空15]you that they would be amazing.1. A. beforeB. afterC. behindD. in front of2. A. moreB. lessC. noD. very3. A. eldestB. youngestC. oldestD. smallest4. A. themB. whomC. whichD. that5. A. there areB. there isC. areD. is6. A. toB. withC. forD. in7. A. treasureB. treasuresC. moneyD. gold8. A. cameB. wentC. brokeD. walked9. A. thoughB. howeverC. everD. since10. A. dayB. momentC. momentsD. days11. A. wearsB. fitsC. liftsD. carries12. A. freshB. electronicC. modernD. scientific13. A. have studiedB. will studyC. studiedD. were studying14. A. have done thatB. did soC. did itD. are doing it15. A. sureB. assureC. insureD. ensure
【单选题】 5.I will visit you if Father me.
①  let
②  lets
③  is letting
④  will let
【单选题】 9.“Has he seen this film?” “Yes. He _______ it several days ago.”
①  saw
②  has seen
③  had seen
④  was seeing