问题 问答题 简答题

按系统调节对象所要求调节指标的不同情况可以把自动调节系统分为几类?

答案

参考答案:

①按系统调节对象所要求调节指标的不同情况可以把自动调节系统分为三类:顺序调节系统、定值调节系统、随动调节系统

②顺序调节系统就是系统的给定值是变化的,但它是1个已知的时间函数,即工艺运行过程需按一定的时间程序来变化

③定值调节系统就是工艺运行中要求调节对象的某一被调节参数保持在1个恒定的指标上不变

④随动调节系统又称为自动跟踪系统,这类系统的特征是,调节对象的某一参数不断发生变化,并要求系统的调节机构也不断做出相应的变化

问答题

In the span of 18 months, Isaac Newton invented calculus, constructed a theory of optics, explained how gravity works and discovered his laws of motion. As a result, 1665 and the early months of 1666 are termed his annus mirabilis. (46)It was a sustained sprint of intellectual achievement that no one thought could ever be equaled. But in a span of a few years just before 1900, it all began to unravel. One phenomenon after another was discovered which could not be explained by the laws of classical physics. (47) The theories of Newton, and of James Clerk Maxwell who followed him in the mid-19th century by crafting a more comprehensive account of electromagnetism, were in trouble.
Then, in 1905, a young patent clerk named Albert Einstein found the way forward. In five remarkable papers, he showed that atoms are real (it was still controversial at the time), presented his special theory of relativity, and put quantum theory on its feet. It was a different achievement from Newton’s year, but Einstein’s annus mirabilis was no less remarkable. He did not, like Newton, have to invent entirely new forms of mathematics. However, he had to revise notions of space and time fundamentally. (48) And unlike Newton, who did not publish his results for nearly 20 years, so obsessed was he with secrecy and working out the details, Einstein released his papers one after another, as a fusillade of ideas.
For Einstein, it was just a beginning-he would go on to create the general theory of relativity and to pioneer quantum mechanics. While Newton came up with one system for explaining the world, Einstein thus came up with two. Unfortunately, his discoveries- relativity and quantum theory-contradict one another. Both cannot be true everywhere, although both are remarkably accurate in their respective domains of the very large and the very small. Einstein would spend the last years of his life attempting to reconcile the two theories, and failing. (49) But then, no one else has succeeded in fixing the problems either, and Einstein was perhaps the one who saw them most clearly.
When Einstein was awarded a Nobel prize, in 1921, it was for the first of his papers of 1905, which proved the existence of photons-particles of light. (50) Up until that paper, completed on March 17th and published in Annalen der Physik (as were the other 1905 papers), light had been supposed to be a wave, since this explains the interference patterns created when it passes through a grating. Einstein, however, began from a different premise, by considering the so-called "black-body experiment".

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