[1] Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA
[2] Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA
[3] Transportat Secur Adm, US Dept Homeland Secur, Atlantic City, NJ 08405 USA
[4] Univ Nevada, Dept Mech Engn, Reno, NV 89557 USA
[5] Univ Nevada, Nevada Ventures Nanosci Program, Reno, NV 89557 USA