炮孔排面与巷道中心线基本垂直其误差不大于() A.±20° B.±30° C.±50

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问题:

炮孔排面与巷道中心线基本垂直其误差不大于()

A.±20°

B.±30°

C.±50°

考点:凿岩爆破工考试凿岩爆破工(高级)凿岩爆破工(高级)题库
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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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从转盘上平面到套管鞋的深度称为()。

A、联顶节方入

B、完钻井深

C、套管深度

D、人工井底

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84被一个数除,商和余数都是7,这个数是______.

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乒乓球的正手加转弧圈球中,站位时重心较低,收腹含胸。引拍时,身体随之(),右肩下沉。

A、右转

B、左转

C、前移

D、后移

题型:单项选择题

轴向位移过大,对机组有哪些危害?

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