micrometer
US /maɪˈkrɑ:mɪtə(r)/
・UK /maɪˈkrɒmɪtə(r)/
C2 高級
n. (c./u.)名詞 (可數/不可數)測微計
The length between the garage and the front door is micrometer away
影片字幕
細胞生物學|簡介細胞 (Cell Biology | Introduction To Cell)
06:29
- So did you all know that A smallest cell is 0.1 to 0.5 micrometer which is of a bacteria
那麼大家知道嗎，一個最小的細胞是0.1到0.5微米，這是細菌的。
如何阻止水結冰 (How to STOP Water From Freezing)
03:55
- I made a previous video about how, since water expands when it freezes, if you try to freeze water inside a rigid container, any of it that becomes ice will expand and pressurize the container, eventually stopping the rest of the water from freezing. So if you have supercooled water inside a rigid container, there aren't just the two competing factions of interior wanting to freeze and surface wanting to melt – there's a third player, pressure. Pressure makes it harder for ice crystals to grow, so pressure, like the surface, wants ice crystals to melt. Obviously, if you have a large amount of water, a tiny amount of it freezing into ice and expanding doesn't pressurize the remaining liquid very much, so a lot of ice can form before there's enough pressure to matter. Pressure simply doesn't come into the picture until way beyond the tipping point size for runaway ice crystal formation. But if you have a tiny amount of water, the pressure can be substantially affected by the formation of even a single tiny ice crystal. For containers that are smaller than a few tenths of a micrometer in size, instead of a tipping point where once an ice crystal gets big enough it keeps growing and growing, in this case the pressure's desire to melt overwhelms the interior's desire to freeze for all crystal sizes, and all ice crystals want to melt regardless of their size. So supercooled water in a tiny, rigid bottle won't freeze no matter how hard you smack it, as long as the bottle is tiny enough. For water 1°C below zero, the bottle needs to be less than 200 nm long.
我以前錄製過一段視頻，講的是由於水在結冰時會膨脹，所以如果你試圖將硬質容器中的水結冰，其中任何結成冰的部分都會膨脹並給容器加壓，最終阻止其餘的水結冰。是以，如果在硬質容器內有過冷的水，就不只是內部想凍結和表面想融化這兩派在競爭，還有第三派，那就是壓力。壓力使冰晶更難生長，是以壓力和表面一樣，希望冰晶融化。很明顯，如果你有大量的水，少量的水凝結成冰並膨脹並不會給剩餘的液體帶來很大的壓力，所以在有足夠的壓力之前就會形成大量的冰。只有當壓力遠遠超過失控冰晶形成的臨界點時，壓力才會出現。但是，如果只有極少量的水，
