a
Department of Precision Science & Technology and Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
E-mail: kasai@dyn.ap.eng.osaka-u.ac.jp
b
On leave from: Department of Physical Sciences, Philippine Normal University, Manila 1000, Philippines
c
Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, Canada