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發表於 3-1-2009 13:00:14
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原帖由 nakeman 於 3-1-2009 12:46 PM 發表 
毛細管呀 ^~^
毛細現象（又稱毛細管作用）是指液體在細管狀物體內側，由於內聚力與附著力的差異、克服地心引力而上升的現象。植物根部吸收的水分能夠經由莖內維管束上升，即是毛細現象最常見的例子。當液體和固體(管壁)之間的附著力大於液體本身內聚力時，就會產生毛細現象。液體在垂直的細管中時液面呈凹或凸狀、以及多孔材質物體能吸收液體皆為此現象所致。
Capillary action, capillarity, capillary motion, or wicking is the ability of a substance to draw another substance into it. The standard reference of capillary action is to a tube in plants, but it can be seen readily with porous paper. It occurs when the adhesive intermolecular forces between the liquid and a substance are stronger than the cohesive intermolecular forces inside the liquid. The effect causes a concave meniscus to form where the substance is touching a vertical surface. The same effect is what causes porous materials such as sponges to soak up liquids.
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[ 本帖最後由 BlackAce 於 3-1-2009 01:03 PM 編輯 ] |
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