| 摘要 |
Particulate material influenced by the acoustic forces in an ultrasonic standing wave is manipulated in a liquid column (16) by the use of at least two standing waves having axes extending transversely across the column at different orientations to its longitudinal axis. The nodes of the standing waves intersect within the column to give regions of greatest acoustic influence that allows a relative displacement between the particles and the liquid in a direction transverse to the axes of the standing waves. The effects of acoustic streaming can be reduced and the physical arrangement of the ultrasound apparatus in relation to the column is simplified. |
