1. State Key Laboratory of Multiphase Flow in Power Engineering; Xi'an Jiaotong University; Xi'an Shaanxi 710049 China
2. Beckman Laser Institute; University of California; Irvine California 92612
3. Department of Mechanical Engineering; The University of Akron; Akron Ohio 44325-3903
4. Laser Treatment Center; Department of Dermatology; Medical School, Xi'an Jiaotong University; Xi'an Shaanxi 710049 China