1. Department of Energy
and Process Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim,
Norway
2. SINTEF Energy Research, Post Office Box 4761, Sluppen, NO-7465
Trondheim, Norway
3. Institute of Materials and Environmental Chemistry,
Research Centre for Natural Sciences, Hungarian Academy of Sciences, Post Office Box 17, Budapest 1525, Hungary