【单选题】【消耗次数:1】
气体在离心式压缩机扩压器中压力将( )。
降低
升高
压力不变
速度升高,压力降低
参考答案:
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相关题目
【单选题】 离心式压缩机是属于( )。
①  高速重载机械
②  容积性压缩机
③  低速运转机械
④  速度型压缩机
【判断题】 当离心式压缩机实际流量小于某流量时,会出现压缩机压力突然下降,出口高压气体倒流回叶轮的现象称为气蚀。( )
①  正确
②  错误
【单选题】 离心式压缩机蜗壳的作用是( )。
①  降低气体速度
②  提高气体速度
③  将压力能转变为动能
④  提高气体压力,收集气体并引出机外
【单选题】 离心式压缩机级间密封常采用( )。
①  机械密封
②  迷宫密封
③  填料密封
④  浮环密封
【单选题】 离心泵、离心式压缩机、鼓风机、蒸汽透平以( )为尺寸基准。
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【单选题】 较高压缩比时,往复式压缩机分段而离心式压缩机一般不分段。( )
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【单选题】 一往复活塞式压缩机工作压力为9MPa,它属于( )压缩机。
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【判断题】 活塞式输油泵中活塞弹簧的预紧力降低,会使柴油机喷油泵低压油腔压力降低,供油量减少
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【多选题】 按压缩气体的方式分类,属于速度型的压缩机有()
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随机题目
【单选题】 Which of the following steps are typical for the deductive grammar teaching method?
①  Give examples→explain rules→students do practice activities
②  Authentic language data is provided→induces learners to realize grammar rules→apply the new structure to produce sentences (the inductive method)
③  Explicit rules are give to students→Authentic language data is provided→apply the new structure to produce sentences (the guided discovery method)
④  All of the above.
【单选题】 Which of the following statement is not true?
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②  There is a positive role of instruction for grammar learning
③  Grammar teaching can enhance learner proficiency
④  Grammar learning is completely useless for children.
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②  Inductive method
③  Guided discovery method
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【单选题】 What is the realistic goal of teaching pronunciation?
①  Consistency
②  Intellegibility
③  Communicative efficiency
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【单选题】 Which type does the following production practice belong to? She sells sea shells on the seashore.
①  Make up sentences
②  Using meaningful context
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【单选题】 Which type does the following production practice belong to? The students repeat what the teacher says. This activity can practice individual sounds, individual words, groups of words, and sentences.
①  Listen and repeat
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【单选题】 What does the falling intonation on the question “where do you live ?” indicate?
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【单选题】 What is reflected as important in the following example? A. Would you please turn down the radio a little bit? B. Sorry. ↘ (no, I do not want to.) Or B. Sorry? ↗ (what did you say?)
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【单选题】 What does the falling intonation on the statement “he is moved to Glasgow.” indicate?
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【单选题】 Which of the following is true about pronunciation teaching?
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