1. University of New Mexico, Albuquerque, New Mexico 87131, United States
2. Haldor Topsøe A/S, Nymøllevej 55, DK-2800 Kgs. Lyngby, Denmark
3. Center for Electron Nanoscopy, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
4. Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States