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在同位旋依赖的量子分子动力学(IQMD)和Boltzmann-Uehling-Uhlenbeck(BUU)的框架下研究了重离子碰撞过程中核物质的剪切粘滞系数与熵密度的比值。用不同的方法提取了剪切粘滞系数(η)、熵密度(s)和其他相关的物理量。随着碰撞能量的增加,粘滞系数和熵密度的比值在BUU模型中逐渐趋于一个饱和值而在IQMD模型中出现了一个极小值,认为这个局域的最小值或饱和值对应于中能重离子碰撞中发生的核物质液气相变现象。
Under the framework of isomorphic-dependent quantum-molecular dynamics (IQMD) and Boltzmann-Uehling-Uhlenbeck (BUU), the ratio of shear viscosity to entropy density of the nuclear matter during heavy ion collisions was studied. Shear viscosity (η), entropy density (s) and other related physical quantities were extracted by different methods. As the collision energy increases, the ratio of the viscosity coefficient to the entropy density gradually becomes a saturation value in the BUU model and a minimum value appears in the IQMD model, and the minimum value or saturation value of this local region corresponds to the middle Liquid Phase Transition of Nuclear Matter Generated in Heavy Ion Collisions.