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[摘要]:We show that thermal creep is at the origin of the recently discovered Leidenfrost ratchet, where liquid droplets float on a vapor layer along a heated sawtooth surface and accelerate to velocities of up to 40 cm/s. As the active element, the asymmetric temperature profile at each ratchet summit rectifies the vapor flow in the boundary layer. This mechanism works at low Reynolds number and provides a novel tool for controlling gas flow at nanostructured surfaces. |
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