“材料要坚韧稳定，但从通电的角度看也需要让电离子顺利通过，”格林浩尔博士说。

"You want it very rigid and stiff, but from an electrical point of view you also want it to allow ions to flow through the material," says Dr Greenhalgh.

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然而男孩子们依然被教育要坚韧，不能哭，要抑制情感，并且，无论话多大的代价都要成为强者。

Yet boys are still taught to be tough, not cry, suppress emotions, and be strong at all costs.

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设计一种适合的膜非常困难：一方面要足够坚韧，以承受压力；但同时还要有渗透性，而且只能透水，不能透盐。

Devising a suitable membrane-tough enough to withstand the pressure while remaining permeable to water but not to salt-is harder than it sounds.

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