中文摘要：

在修改的Fisher模型框架下,利用同质异位素产额比和结合能方程中对称能系数与温度比率的关联,可以提取对称能系数与温度的比值。利用3种不同的近似方法得到了重离子核反应产生丰中子余核的对称能系数与温度比（asym/T）,并研究了相关物理量对asym/T的影响。结果表明,库仑能对提取丰中子余核的asym/T影响较小,且参考核的选取对asym/T的提取也有一定的影响。

英文摘要：

In the framework of the modified Fisher model, correlations between the symmetry-energy coef- ficient in semi-classical mass formula to temperature （asym/Z） and the isobaric yield ratio in Heavy-ion col- lisions are established, asym/Z of neutron-rich fragments are extracted using these correlations. It is found that the Coulomb-energy term has little effect on asym/T of fragments, while the reference isobars adopted have great influence on the extracted asyrn/r of fragments.