FIG. 2.

Phase pattern with a modulation (a) from 0° to −360° and (b) from −90° to −270°, illustrating the method as well as the different characteristic times involved. (c) Position of the particles corresponding to time instants I, II, and III in subfigure (a) or (b). (c)/I. Particle trapping at the beginning of sorting. (c)/II. At the end of ramping period, small particles and large particles are located above and below the antinode, respectively. (c)/III. The two types of particles relax to different nodal lines by the end of the resting period. (d) The distribution of the acoustic radiation force (orange curve and arrows) in the microchannel at phase 0°.