Affiliation: | Xue-Juan Yang1,2,Fang-Jun Lu2,Bernd Aschenbach3 and Li Chen4 1 Faculty of Materials,Optoelectronics and Physics,Xiangtan University,Xiangtan 411105,China 2 Particle Astrophysics Center,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China 3 Max-Planck-Institut fu¨r Extraterrestrische Physik,85741 Garching,Germany 4 Department of Astronomy,Beijing Normal University,Beijing 100875,China |