In some systems, foam at the surface may not cause a lot of damage, but the presence of a foam layer normally indicates extensive air entrainment.

在一些系统中，油液表面的泡沫不会造成很大的损害，但泡沫的存在说明相当量的空气滞留在油液当中。

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Penetration performance in surface layer of concrete target was analyzed by stress wave damage theory, calculating method base on "simplified equivalent resistance line" was presented.

从应力波表层损伤理论分析了混凝土表层“开坑区”的侵彻特性，提出“简化等效阻力线”的计算方法；

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Experimental study shows that the damage rate of fracturing fluid to fracture surface is between 31. 84% and 36. 28%; the damage rate to propping agent layer is between 29. 27% and 30. 04%.

针对太2气层的实验研究表明，压裂液对裂缝壁面的伤害率平均在31.84% - 36.28%之间，压裂液对支撑剂层的伤害率平均在29.27%—30.04%之间。

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The result is that any coating, such as an antibacterial layer, would be "self-repairing" after small amounts of damage, as the molecular chains just below the damaged layer re-cover the surface.

BBC: Coating heals itself after damage