β衰变与中子发射 symmetry studies with francium slow neutron 100 capture process (s heavy element . proces studies proton dripline fission limits doubly magic Sn (8 Z N=Z nuclei nuclei with large neutron excess rapid proton capture process rapid neutron (rp-process) doubynagic 132c. capture process (r-process weakening o -neutron dripline shell structure hao nucleI 50 150β衰变与中子发射