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金湖县泌尿科咨询淮安中山医院可以做包皮手术?淮安市妇幼保健医院妇科检查多少钱 Sublimation升华现象Sublimation on this moment of science.今天我们的节目要讲的是:升华现象。Pop quiz, everybody put away your books, and keep your eyes on your own radio.各位,请放下你们手中的书本,专心听收音机,我们来做一个突击测验。You fill the ice tray up to the rim and put it in the freezer. The ice that results will be用水将冰格填得满满的,漫过冰格的边缘,然后再将冰格放到冰箱的制冷室里,最后结成的冰会:a. at the rim b. over the rim c. under the rim. Answer? It depends.a. 刚好齐边 b. 边缘以上 c. 边缘以下 是?要看情况而定。I know, you hate that. But it does depend —it depends on how long you wait before checking on the ice again. My guess would be that most folks chose answer b: over the rim. That is correct, if you checked on the ice trays after only a couple hours. Thats because water expands when it turns into ice, as you know if you ever put a soda bottle in the freezer and came back to find it exploded all over the fish sticks.我明白,你们不喜欢这样的。但是,实际情况确实如此——取决于你要过多长时间去查看。我猜,很多人都会选择b选项:边缘以上。如果你在放入制冷室仅两个小时之后去查看的话,这个就是正确的。这是因为水在变成冰的时候会膨胀。就像大家所知道的,如果将一瓶汽水放在制冷室中,回头去看的时候会发现,汽水已经炸开了,整个制冷室中到处都是汽水。But if you were to leave the ice tray untouched for a couple of months, you might find the ice to be under the rim, or lower than the water was.但是,如果你将冰格放在制冷室中,好几个月都不动它的话,你会发现,冰在边缘以下,或是低于你之前装的水的高度。Huh? Didnt we just say water expands when it freezes? Initially, yes. But frozen water can do something else as well: it can sublimate. To sublimate is to go from one state to another without passing through the usual intermediary state.哈?我们刚刚不是才说了水在变成冰的时候会膨胀吗?最开始的时候,会。但是冷冻之后的水也会有其他的变化:升华。升华也就是物质不经中间状态直接从一个状态转变成另一个状态。By adding heat, ice can be melted into liquid water, which can be evaporated. Thats three states: solid, liquid, gas. But given enough time, ice can also turn into a gas without melting first! When your ice cubes seem to have shrunk, its because they are sublimating: the frozen water is slowly evaporating off the cubes, without ever actually melting.通过加热,冰可以化成液态水,液态水可以被蒸发为水蒸气。这是三个状态:固态,液态,气态。但是,如果时间足够的话,冰可以在不被融化的情况下转变为气态。如果你的冰“缩水”了,那是因为被升华了:在没有被融化的情况下,固态水以非常缓慢的速度在蒸发着。Will this work in any freezer? Next time.这种现象在任何的制冷器中都会出现吗?下次再谈。 /201208/194828Because we actually think it might be some kind of metallic coating almost like a priate full s something sparkling which means even better than looking at snow.因为我们真的认为它可能是一种金属外衣,几乎闪闪发光,这意味着甚至比雪看起来还好看。These are just some puzzles that European Space Agencys Venus Express now in orbit its hoping to solve.这些都只是欧洲太空总署希望通过轨道上的金星探测器能解决的一些困惑。As we begin to understand how carbon dioxide controls our climate theres never been a better time to learn lessons from our neighbour.当我们开始了解二氧化碳如何控制我们的气候,而从来没有如此美好的时光,那就是我们能从我们的邻居那里汲取教训。What we are trying to solve now with this very dense atmosphere very complex weather patterns with new data from Venus express ,我们正设法利用从金星获取的最新数据解决这厚厚的大气层及非常复杂的天气形态,We are really learning by mapping out 3 dimensions how the atmosphere behaves.我们真的是学习如何绘制出三维空间中大气的应用情况。Unprotected by the magnetic shield Venus is still being robbed of precious water.没有保护罩保护的金星上宝贵的水资源正在消耗殆尽。Venus express has seen how the solar wind eats away the atmosphere.金星快车已经见了太阳风侵蚀大气层。You can see that even today that actually water is still escaping from oxygen and Hydrogen thats in the case that has been water.你可以看到,即使在今天,真正的水仍然从氧气和氢气中逃离。注:听力文本来源于普特 201203/176196淮安早泄做手术需要多少钱

盱眙县中医院官网淮安82医院肛肠科 Seven Puget Sound killer whales are missing and presumed dead in what could be the biggest decline among the sounds orcas in nearly a decade, say scientists who carefully track the endangered animals.七头逆戟鲸在普吉特海湾失踪。据推测,它们已经死亡。跟踪调查则这一濒危物种的科学家说,这是该海域近10年来发生的最大规模的逆戟鲸死亡事件。;This is a disaster,; Ken Balcomb, a senior scientist at the Center for Whale Research on San Juan Island, said.“这是一场灾难”,圣胡安岛鲸鱼研究中心的资深科学家肯-巴尔科姆这样说道。While the official census wont be completed until December, the total number of live ;southern resident; orcas now stands at 83.官方对逆戟鲸数量的普查要到12月 才能完成。这些 “南部居民”的总数如今大约是83头。Among those missing since last years count are the nearly century-old leader of one of the three southern resident pods, and two young females who recently bore calves. The loss of the seven whales would be the biggest decline among the Puget Sound orcas since 1999, when the center also tracked a decline of seven whales.自去年以来,失踪者中包括三大“南部居民”群体之一中的一个首领,它已经将近100岁了;还有两头是最近才产下幼崽的年轻雌鲸。这七头逆戟鲸的失踪是普吉特海湾自1999年以来发生的最大规模的逆戟鲸死亡事件,当时的1999年圣胡安岛鲸鱼研究中心还跟踪到另外七头逆戟鲸失踪。Low numbers of chinook salmon, a prime food for these whales, may be a factor in the unusual number of deaths this year, Balcomb said.作为逆戟鲸主要食物来源的鲑鱼数量的下降可能是今年逆戟鲸不正常死亡的一个因素,巴尔科姆说。 注:本文译文属原创,,。201204/180043淮安中山医院预约挂号系统

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