1. School of Materials Science and EngineeringUniversity of Science and Technology Beijing Beijing 100083 China
2. Key Laboratory for Biomass Gasification Technology of Shandong Province, Energy Research InstituteQilu University of Technology (Shandong Academy of Sciences) Jinan 250014 China
3. Institute of High Energy PhysicsChinese Academy of Sciences Yuquan Road 19B, Shijingshan District, P.O. Box 918 Beijing 100049 China