2015.05.09【英译中】简明科技知识问答手册——物理和化学(3)

yangf2014 (不灭孽蜥) 译译生辉
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发表于:2015-05-09 16:11 [只看楼主] [划词开启]

Why do golf balls have dimples?

高尔夫球表面的凹纹有什么作用?

        The dimples minimize the drag(a force that makes a body lose energy as it moves through a fluid),allowing the ball to travel further than a smooth ball would.The air ,as it passes a dimpled ball,tends to cling to the ball longer,reducing the eddies or wake effect that drain the ball`s energy.The dimpled ball can travel up to 300 yards(275 meters),but a smooth ball only goes 70 yards(65 meters).A ball can have 300 to 500 dimples that can be 0.01 inch(0.25 millimeter) deep.Another effect to get distance is to give the ball a backspin.With a backspin there is less air pressure on the top of the ball,so the ballstays aloft longer(much like an airplane).

       凹纹能减小拉力(一种能使球体在穿越液体时损失能量的力),使高尔夫球比光滑的球飞得更远。空气,经过凹纹时,需要更久的时间,降低了漩涡或者降低高尔夫球的能量损耗。有凹纹的球能飞300码(275米),但是一个光滑的球仅能飞70码(65米)。一个球有300到500道凹纹时仅仅有0.01英寸(0.25毫米)深。另一个效果是是使高尔夫球得到回旋。回旋使得作用在球上的气压降低,所以球能在高处飞的更久(更像一架飞机)。

What is Maxwll`s demon?

什么是麦克斯韦恶魔?

        An imaginary creature who,by opening and shutting a tiny door between two volumes of gases,could,in principle,concentrate slower molecules in one(making it colder) and faster molecules in the other(making it hotter),thus breaking the second law of thermodynamics,Essentially this law states that heat does not naturally flow from a colder body to a hotter body;work must be expended to make it do so.This hypothesis was formulated in 1871 by James C.Maxwell(1831-1879),who is considered to be the greatest theoretical physicist of the 19th century.The excess energy would be useful to perform work and the system would be a perpetual motion machine.About 1950,the French physicist Leon Brillouin disproved Maxwell`s hypothesis by demonstrating that the decrease in entropy resulting from the demon`s actions would be exceeded by the increase in entropy in choosing between the fast and slow molecules.

       一个理想的生物,能够用两种气体体积打开和关闭一扇小门,原则上速度慢的分子会集中(变得更冷),速度快的份子会集中(变得更热),这会打破热力学第二定律,这一定律本质上建立在热能不会自然地从低温物体想高温物体转移;但是必须这么假设以扩充概念。这一假说在1871年由詹姆斯·C·麦克斯韦建立(1831-1879年),他被认为是19世纪世界上最伟大的理论物理学家。这超额的能量能用于完成工作,而这个系统会变成永动机。大约在1950年,法国物理学家里昂·布里渊终结了麦克斯韦理论,他论述道这是由恶魔的手在快的分子和慢的分子选择减少还是增加熵。

分类: 英语
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