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引起汽轮机大轴弯曲的主要原因有哪些?

答案

参考答案:

汽轮机在运行中引起大轴弯曲的主要原因有以下几种情况:

①.动静部分摩擦使转子局部过热;

②.停机后在汽缸温度较高,由于某种原因使冷水进入汽缸,引起高温状态的转子下侧接触到冷水,局部冷却,出现很大的上下温差而产生热变形,造成大轴弯曲。当转子上下温差达到150—200℃时,就会造成大轴弯曲。转子金属温度越高,越容易造成大轴弯曲。

③.转子的原材料存在过大的内应力,在较高的工作温度下经过一段时间的运转后,内应力逐渐得到释放,从而使转子产生弯曲变形。

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For the first time, George Bush has acknowledged the existence of secret CIA prisons around the world, where key terrorist suspects—100 in all, officials say—have been interrogated with "an alternative set of procedures". Fourteen of the suspects, including the alleged mastermind of the September 11th attacks, were transferred on Monday to the American naval base at Guantánamo Bay in Cuba, where some will face trial for war crimes before special military commissions.

Many of these men—as Mr. Bush confirmed in a televised speech at the White House on September 6th—are al-Qaeda operatives or Taliban fighters who had sought to withhold information that could "save American lives". "In these cases, it has been necessary to move these individuals to an environment where they can be held secretly (and) questioned by experts," the president said. He declined to say where they had been held or why they had not simply been sent straight to Guantánamo, as some 770 other suspected terrorists have been.

Mr. Bush also refused to reveal what interrogation methods had been used, saying only that, though "tough", they had been "safe and lawful and necessary". Many believe that the main purpose of the CIA’s prisons was to hide from prying eyes the torture and other cruel or degrading treatment used to extract information from prisoners. But Mr. Bush insisted that America did not torture : "It’s against our laws, and it’s against our values. I have not authorised it—and I will not authorise it."

The Pentagon this week issued its long-awaited new Army Field Manual, forbidding all forms of torture and degrading treatment of prisoners by army personnel—though not the CIA. For the first time, it specifically bans forced nakedness, hooding, the use of dogs, sexual humiliation and "waterboarding" (simulated drowning )—all practices that have been used at Guantámamo and Abu Ghraib.

So why did the president decide now to reveal the CIA’s secret programme Partly, he confessed, because of the Supreme Court’s recent ruling that minimum protections under the Geneva Conventions applied to all military prisoners, no matter where they were. This has put American agents at risk of prosecution for war crimes. Mr. Bush has now asked Congress to ban suspected terrorists from suing American personnel in federal courts.

In terms of literary device, the phrase "an alternative set of procedures" in the first paragraph of the text is a kind of()

A. hyperbole

B. euphemism

C. black humor

D. stream of consciousness