1. Department of Chemical Engineering and Materials Science Michigan State University East Lansing Michigan 48824‐1226
2. Department of Advanced Materials Engineering Kookmin University Seoul 136‐702 Korea
3. Army Research Laboratory RDRL‐SED‐C 2800 Powder Mill Road Adelphi Maryland 20783
4. Department of Mechanical Engineering University of Michigan Ann Arbor Michigan 48109‐2125