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“永久气体”成了历史名詞 我們知道,水本身是液体,然而冷了会結成冰,受热又会化成水蒸气。这真是变化多端。实际上,不仅是水,所有的物質都有固态、液态和气态这三态的变化。比如,人們很早就發現銅和铁加热会熔化,还能化成蒸气。水銀在北方能够冻硬,而受热也能气化。但是普通气体的液化和再进一步凝固,就比較困难了,以往人們認为是不能实現的。懂得一点物質構造的知識的人都知道:在液态的时候,分子间的距离要比在气态的时候小。看起來,似乎只是將气体压縮,使得分子间的距离縮小,就能够使气体凝結成为液体。当然,这对有的气体是正确的。比如氨气,就可以用压縮方法,使它变成液体,甚至进而变成固体。但是,对于其他許多气体,單純用压縮方法就不行了,必
“Permanent gas” has become a historical term. We know that water itself is a liquid, but when it is cold, it will form ice, and when heated, it will turn into water vapor. This is really changing. In fact, not only water, but all substances have solid, liquid, and gaseous three-state changes. For example, people have long found that the heating of copper and iron will melt, but also into steam. Mercury can be hard frozen in the north, but it can also be gasified by heat. However, the liquefaction of ordinary gases and the further solidification of the gas are difficult. In the past, it was considered impossible to achieve. Those who know a bit of material structure knowledge know that when in the liquid state, the distance between molecules is smaller than when they are in the gaseous state. It seems that it seems that only the gas is compressed so that the distance between the molecules is reduced, and the gas can be condensed into a liquid. Of course, this is correct for some gases. Ammonia, for example, can be compressed to make it liquid, and even become solid. However, for many other gases, simply using compression methods will not work.