An easement is a segment of a spiral that provides a smooth transition between tangents and curves, and curves of different radius.

介曲线是一组用来保证在直轨和弯道之间，以及不同半径的弯道之间进行平稳过渡的螺旋线。

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When the three researchers programmed their model to arrange PS10's mirrors in front of the tower in a segment from such a spiral, they both improved the efficiency of the collection process and saved space.

ECONOMIST: Solar energy