1. Materials Science & Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
2. Center for Biomolecular Science & Engineering, Naval Research Laboratory, Washington, D.C. 20375, United States
3. College of Science, George Mason University, Fairfax, Virginia 22030, United States
4. Electronics Science & Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
5. Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States