1. Utsunomiya University Department of Energy and Environmental Science, Utsunomiya 321-8585, Japan
2. Tokyo Institute of Technology, Department of Environmental Science and Technology Nagatsuta 4259, Japan
3. Utsunomiya University, Department of Energy and Environmental Science Utsunomiya 321-8585, Japan and Technical University of Varna, Department of Physics, Varna 9010, Bulgaria