RT Journal T1 The bound states of two dimensional ring delta potential A1 PB College Physics FD 2011-10-25 YR 2011 JF College Physics JO College Physics VO 30 IS 10 SP 55 DO K1 ring delta potential;bound states;Tricomi function LK {http://dxwl.bnu.edu.cn/EN/article/article_1872.shtml}