摘要
In order to investigate the evolution of the isospin fractionation degree, (N/Z)n/(N/Z)Nimf with the neutron to proton ratio of the colliding system , Fig.1 shows the (N/Z)n/(N/Z)Nimf as a function of the neutron-proton ratio of the colliding system for the reactions 104Sn+104Sn,112Sn+112Sn and 124Sn+124Sn at the beam energy of 50 MeV/u and impact parameter 6=0.0 fm (right window) and 4.0 fm (left window) , where the neutron to proton ratios of the above three colliding systems are 1.01, 1.34 and 1.48. In Fig.l there are three
