[en] Temperature of 5 MeV was extracted from double isotope ratios [(Y_6Li/Y_7Li)/(Y_3He/Y_4He)] measured at backward angle in laboratory system in the reaction 30 MeV/u ⁴⁰Ar + ^natAg. It is observed that this temperature increases continuously from 5 MeV to 6 MeV with the increase of the energy threshold E_cut/A. A Monte Carlo simulation on particle emission process of hot nuclei shows that the average temperature of hot nuclei as emission sources goes up gradually with increasing energies of emitted particles. It is demonstrated that hot nuclei with higher temperature are more probable to emit higher energy particles