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在杯子中升华的干冰会释放二氧化碳进入大气。


昇華是指一种物质从固态不经过液态直接转化为气态的过程，是物质在温度和气压低于三相点的时候发生的一种物态变化。与昇華相反的过程称做凝華，指物质从气态直接变成固态。這樣的例子有結霜[1]。昇華是吸熱的反應，所需的焓是汽化熱和熔化热之和。




目录






  • 1 例子


  • 2 昇華作用


  • 3 日文中的“升华”（物理·化学术语）


  • 4 参见


  • 5 参考资料





例子


砷在高溫可以昇華。鋅和鎘在低壓下可昇華。


白炽灯的钨丝在使用过程中逐渐变细，也是升华现象。


固體二氧化碳（乾冰）、萘、三聚氰胺、和無水三氯化鋁等都可以昇華。


而碘其實不是昇華，因為它在高於三相點時發生了固體變成氣體的物理變化。有上述之變化是因為碘的蒸氣壓低於大氣壓，故會氣化。



昇華作用


一些物質由固體直接轉化為氣體



日文中的“升华”（物理·化学术语）


日文中的“升华”一词既可以指从固态直接到气态的变化过程，也可以指从气态到固态的变化过程（即中文中的“凝华”）。不过，日文中有时也用“凝固”一词指代凝华的概念（虽然日语中的“凝固”和中文一样，主要是指从液态到固态的变化过程）。



参见



  • 熔化

  • 蒸发

  • 沸腾

  • 凝結

  • 凝固

  • 凝華















































参考资料





  1. ^ Boreyko, Jonathan B.; Hansen, Ryan R.; Murphy, Kevin R.; Nath, Saurabh; Retterer, Scott T.; Collier, C. Patrick. Controlling condensation and frost growth with chemical micropatterns. Scientific Reports. 2016, 6: 19131. Bibcode:2016NatSR...619131B. PMC 4726256. PMID 26796663. doi:10.1038/srep19131. 




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