The conventional bilinear fitting method often entails ambiguity in selecting fitting ranges for low and high temperatures, leading to potential human bias. To circumvent this issue, a slope-temperature analysis can be employed, where each point on the plot corresponds to the slope derived from a linear regression of densities within the temperature range of [T, T+50] . In Figure , the transitions of slopes from low to high temperatures are clearly observable for the lower cooling rate in the continuous cooling method and the step-wise cooling method, where two annealing methods give almost identical results.