[1] Univ Padua, Dipartimento Ingn Meccan, I-35100 Padua, Italy
[2] Ist Giordano SPA, Bellaria, RN, Italy
[3] Inst Neue Mat, INM, D-66123 Saarbrucken, Germany
[4] URA CNRS, Lab Chim Mol, F-06108 Nice, France
[5] CSIC, Inst Ceram & Vidrio, Madrid 28500, Spain
[6] Philips Res Labs, NL-5656 AA Eindhoven, Netherlands
[7] ZGE, Fa E Merc, D-64293 Darmstadt, Germany
[8] Gel Design & Engn GDE, I-28100 Novara, Italy