1. LiCrylINFM (Liquid Crystal Regional Laboratory), c/o Department of Physics, University of Calabria, Via P. Bucci Cubo 31C, I-87036 Rende (CS), and ENEA (Italian Agency for New Technologies, Energy and the Environment), IDROCOMB, C.R. Casaccia, Via Anguillarese 301, 00060 Rome, Italy