Soft granular particles sheared at a controlled volume: rate-dependent dynamics and the solid–fluid transition

We study responses of fluid-immersed hydrogel spheres to either fixed shear rates or sudden cessations. Time-resolved stress measurements and refraction-index-matched internal imaging unveil the rich rate-dependent dynamics across the jamming point.

Symmetric Distortion Correction in Asphere Manufacturing

A method of symmetric distortion correction is described and successfully applied to correct the distortion mapping errors caused by CGH as well as internal imaging optics. The aspheric surface is 160 mm in diameter and has a maximum departure of 145 μm. According to the model established by the fiducial spots on the aspheric surface, we show experimental results after direct measurement and distortion-corrected error map respectively. The results show that the method of symmetric distortion correction is useful and effective.