1. Department of Nuclear Engineering, Faculty of Engineering, Tohoku University Aramaki-Aza-Aoba, Aobaku, Sendai 980–77, Japan
2. Laboratory of Plant and Environmental Research, Faculty of Agriculture Tohoku University Tsutsumidori-amamiyacho, Aobaku. Sendai 981, Japan
3. Department of Chemistry, College of Education, Akita University Tegatagakuen-machi, Akita 010, Japan
4. Cyclotron and Radioisotope Center, Tohoku University Aramaki-Aza-Aoba, Aobaku, Sendai 980–77, Japan