LIU Zhi-Hua1**, ZHANG Yu-Qi2, LIU Bi-Fu3, LIU Jun-Hua1
1. Huizhou No.1 Middle School, Huizhou 516007,China; 2. Huiyang District No.5 Middle School of Huizhou City,Huizhou 516200, China; 3. School of Chemistry and Materials Engineering, Huizhou College, Huizhou 516007,China