抄録
The ultrasound (US) irradiation technique have efficacy to regulate the nucleation and growth of
crystal. The effect of the US frequency on the crystal morphology in the cooling crystallization process of
L-aspartic acid was tested using 26kHz, 78kHz and 130kHz US at 298K. Rod-like crystals were sufficiently
formed under 130kHz US, where the mode of the breadth/length ratio was almost 0.1. Plate-like crystals were
partially observed with 130kHz US. In spite of the high yield of rod-like crystals with US irradiation, XRD
patterns of the crystals have remarkable peak of (200)-plane which is characteristic for the plate-like α type
crystal of L-aspartic acid. This result suggests that rod-like crystals formed under US irradiation are the
polysynthetic twin composed of small size plate-like crystals.
