1. State Key Laboratory of Coal ConversionInstitute of Coal ChemistryChinese Academy of Sciences Taiyuan 030001 China
2. Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of Sciences Beijing 100049 China
3. Department of Materials EngineeringTaiyuan Institute of Technology Taiyuan 030008 China
4. Guangxi University of Science and Technology Liuzhou 545000 China
5. School of Petrochemical EngineeringChangzhou University Changzhou 213164 China
6. Institute of Materials EngineeringUniversity of Siegen Siegen 57076 Germany