1. Xiamen University Tan Kah Kee College, Xiamen 363105, P. R. China
2. Department of Mechanical Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 807, Taiwan
3. Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 811, Taiwan
4. Department of Aeronautical Engineering, Chaoyang University of Technology, Taichung 413, Taiwan