1. Department of Physics, Kwansei Gakuin University, Gakuen, Sanda, Hyogo 669-1337, Japan
2. Heat Physics Department, Uzbek Academy of Sciences, 28 Katartal Street, 100135 Tashkent, Uzbekistan
3. Department of Applied Physics, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan