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裸奔上7都是牛人啊,第一篇阅读我给个近似原文的考古吧,LZ方便的话就确认一下,等整理的同学到岗了方便收入:
P1:说某钟S clock可以说是世界上最后的机械钟了,而且有两个,一个在爱丁堡,一个在某observing station。这种钟就两个钟摆(pendulum):时针和分针,thefirst(时针)在一个真空(vacuum)的容器中,另一个来管钟的指针,然后分针通过一个什么linkage, 好像是electronicdevice之类的运动,时针转动多少分针转动多少。第一个钟摆会根据第二个钟摆信号,来进行适度调整,这个钟就是靠这个运行的 P2:主要讲这种钟如何准确,有一些数字,最后一句说,利用这个钟测出了日月引力对地环转速的影响(有题),发现地球季节性变化 P3:讲在1984年做了一个试验,将这种机械钟与automaticclock做比较,结果发现这种引力会使机械种有一定的误差, 这个误差是受到地球转动的影响;几十年后有人使用80年代后的一种动力,替代了以前使用的动力,然后再对钟表的误差进行测量,发现钟表的误差受到月亮还有潮汐的影响。 P4:说其实陆地像海洋一样也受引力影响有涨潮落潮,但没说那个钟直接证明了这个
近似原文 The Shortt clock had two pendulums.The first, known as the master, swung freely in an evacuated case. Its only jobwas to synchronize the swing of the second pendulum, called the slave, whichwas housed in a neighboring cabinet. Every 30 seconds the slave sent anelectrical signal to give a nudge to the master. In return, via an elaborateelectromechanical link, the master ensured that the slave never got out ofstep. Shortt clocks were standard provision in astronomical observatories of the1920s and 1930s, and are credited with keeping time to better than 2milliseconds a day. Many were on record as losing or gaining no more than 1second a year – a stability of one part in 30 million. The first indications ofseasonal variations in the Earth’s rotation were gleaned by the use of Shorttclocks. In 1984 Pierre Boucheron carried out a study of a Shortt clock which hadsurvived in the basement of the US Naval Observatory since 1932. Using the modernoptical sensing equipment instead of the electromechanical coupling, hemeasured its rate against the observatory’s atomic clocks for a month. He foundthat it was stable to 200 microseconds a day over this period, equivalent totwo to three parts in a billion. What is more, the data also reveal that theclock was sensing the distortion of the Earth due to tides from the Moon andthe Sun.
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