1. National Synchrotron Radiation Research Center Hsinchu 30076 Taiwan
2. Institute of Materials Science and Engineering National Central University Chungli 32001 Taiwan
3. Department of Mechanical Engineering National Central University Chungli 32001 Taiwan
4. School of Chemical Engineering The University of New South Wales Sydney Kensington NSW 2052 Australia
5. Department of Electrophysics National Chiao Tung University Hsinchu 30076 Taiwan