Affiliation: | (1) Institute of Physics, Czechoslovak Academy of Sciences, Cukrovarnická 10, 16000 Prague 6, Czechoslovakia;(2) Dipartimento di Ingegneria Meccanica, Sez. Materiali, Via Marzolo 9, 35100 Padova, Italy;(3) Institute of Chemical Process Fundamentals, Czechoslovak Academy of Sciences, 165 02 Prague 6, Czechoslovakia;(4) Department of Solid State Physics, Masaryk University, Kotláská 2, Brno, Czechoslovakia |