1. Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433, USA
2. Biological and Nanoscale Technologies, UES, Inc., Beavercreek, Ohio 45432, USA
3. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
4. National Research Council, Washington, District of Columbia 20001, USA