调速性能指标有哪些?

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问题:

调速性能指标有哪些?

考点:运动控制系统运动控制系统题库
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测量时,仪表的量限应选择比被测量的数值大()倍左右,以防损坏表头。

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已经立起的杆塔,回填夯实后方可撤去拉绳及叉杆。回填土块直径应不大于(),回填应按规定分层夯实。

A.30mm

B.40mm

C.50mm

D.60mm

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机车空气制动系统装有二台NPT5型空气压缩机,容积流量2.4m3/min。所产生的压缩空气充入两个容量为2*625=1250L的总风缸,以各供()等用风。

A.机车车辆制动系统

B.机车撒砂系统

C.电空控制机构

D.其他各种风动装置

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如图所示,物块A放在木板上,当缓慢倾斜木板,使木板与水平线成倾角a分别为时,对应测得物体受到的摩擦力大小相同,由以上信息可求出物块和木板间的动摩擦因数为()

A.0.5

B.

C.

D.

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Text 4

Humour, which ought to give rise to only the most light-hearted and gay feelings, can often stir up vehemence and animosity. Evidently it is dearer to us than we realize. Men will take almost any kind of criticism except the observation that they have no sense of humour. A man will admit to being a coward or a liar or a thief or a poor mechanic or a bad swimmer, but tell him he has a dreadful sense of humour and you might as well have slandered his mother. Even if he is civilized enough to pretend to make light of your statement, he will still secretly believe that he has not only a good sense of humour but one superior to most. He has, in other words, a completely blind spot on the subject. This is all the more surprising when you consider that not one man in ten million can give you any kind of intelligent answer as to what humour is or why he laughs.
One day when I was about twelve years old, it occurred to me to wonder about the phenomenon of laughter. At first I thought it is easy enough to see what I laugh at and why I am amused, but why at such times do I open my mouth and exhale in jerking gasps and wrinkle up my eyes and throw back my head and halloo like an animal Why do I not instead rap four times on the top of my head or whistle or whirl about
That was over twenty years ago and I am still wondering, except that I now no longer even take my first assumption for granted, I no longer clearly understand why I laugh at what amuses me nor why things are amusing. I have illustrious company in my confusion, of course. Many of the great minds of history have brought their power of concentration to bear on the mystery of humour, and, to date, their conclusions are so contradictory and ephemeral that they cannot possibly be classified as scientific.
Many definitions of the comical are incomplete and many are simply rewordings of things we already know. Aristotle, for example, defined the ridiculous as that which is incongruous but represents neither danger nor pain. But that seems to me to be a most inadequate sort of observation, for if at this minute I insert here the word rutabagas, I have introduced something in congruous, something not funny. Of course, it must be admitted that Aristotle did not claim that every painless incongruity is ridiculous, but as soon as we have gone as far as this admission, we begin to see that we have come to grips with a ghost: when we think we have it pinned, it suddenly appears behind us, mocking us.
An all-embracing definition of humour has been attempted by many philosophers, but no definition, no formula has ever been devised that is entirely satisfactory. Aristotle’s definition has come to be known loosely as the "disappointment" theory, or the "frustrated expectation". But he also discussed another theory borrowed in part from Plato which states that the pleasure we derive in laughing is an enjoyment of the misfortune of others, due to a momentary feeling of superiority or gratified vanity in appreciation of the fact that we ourselves are not in the observed predicament.

Which of the following can be inferred from the first paragraph

A.People don’t like to be considered as having no sense of humoar.

B.People will give you a satisfactory answer to what humour is.

C.People would like to be liars or a cowards.

D.People can make light of other’s comments on their sense of humour.

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