1. Materials research program and the Texas Materials Institute University of Texas at Austin Austin TX 78712 USA
2. School of Chemistry and Chemical Engineering Hefei University of Technology Hefei Anhui 230009 P.R. China
3. High Pressure Science and Engineering Center University of Nevada Las Vegas NV 89154 USA
4. Center for Integrated Nanotechnologies Las Los Alamos National Laboratory Los Alamos NM 87545 USA