A small curve in the sliding part of the convex top of the lower nut acts as the wedge.

下螺母凸顶的滑动零件上有一条小弧线充当楔块。

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Water surges from the cells on the inside of the leaf to those on the outside, causing the leaf to rapidly flip in shape from convex to concave, like a soft contact lens.

水从叶子内部的细胞涌向外面的细胞，导致叶子迅速地从凸向凹翻转，就像一片柔软的隐形眼镜。

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They're lenses because they're convex vessels, and when they're full of water, they act as a lens and you see the horizon in them, upside down and backwards.

它们是透镜，因为它们是凸面容器，当它们盛满水后，它们可作为透镜使用，你可以看到它们里面上下颠倒的地平线。

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The moon was above us, a convex shape almost crushing us, a ruined roof, studded with holes like a cheese grater.

NEWYORKER: The Daughters of the Moon

At Wooller in Northumberland, however, the hilltop is level, with a convex sloping shoulder.

ECONOMIST: Margaret Gelling

But then a colleague at his Atlanta investment company, Convex Group, passed him a plastic lid with a coupon attached to it in August 2002.

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