Affiliation: | a Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 18000 Prague 8, Czech Republic b Institut of Physics, Charles University, V Holesovickach 2, 18000 Prague 8, Czech Republic c Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, 1121 Budapest XII., Konkoly-Thege u. 29-33. Hungary |