**Acknowledgements**

The author is thankful to Prof. M. Kodama, Prof. S. A. Feller, Prof. M. Affatigato, Prof. V. N. Novikov, Prof. M. Maczka, Prof. J.H. Ko, Prof. O. Yamamuro, Prof. H. Anwar, and Dr. Y. Matsuda for their collaboration and fruitful discussions. The author is also thankful to M. Kawashima, Y. Fukawa, K. Kaneda, S. Aramomi, and T. Sunaoshi for the experiments.
