1. Department of Materials Science and Engineering, State University of New York at Stony Brook, Stony Brook, New York 11794; Department of Chemical Engineering and Chemistry, Polytechnic University, Brooklyn, New York 11201; Stella K. Abraham High School, Hewlett, New York 11557; Department of Science and Engineering, Gwanju Institute of Science and Technology, Gwanju, 500-712, Korea; and Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899