1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University Xindu Street 8, Xindu District Chengdu Sichuan Province 610500 China
2. Dep. Interface Chemistry and Surface Engineering Max-Planck-Institut für Eisenforschung GmbH Max-Planck-Str.1 D-40237 Düsseldorf
3. Dep. Materials Science and Engineering NTNU, Norwegian University of Science and Technology NO-7491 Trondheim Norway