A phenomenological equation of state for isospin asymmetric nuclear matter

A phenomenological momentum-independent(MID) model is constructed to describe the equation of state(EOS) for isospin asymmetric nuclear matter,especially the density dependence of the nuclear symmetry energy Esym(ρ).This model can reasonably describe the general properties of the EOS for symmetric nuclear matter and the symmetry energy predicted by both the sophisticated isospin and momentum dependent MDI model and the Skyrme-Hartree-Fock approach.We find that there exists a nicely linear correlation betwee...     

径向膨胀流的同位旋效应

利用同位旋相关的量子分子动力学模型,研究了¹²⁴Ba+¹²⁴Ba和¹²⁴Sn+¹²⁴Sn两个系统在不同入射能量下对心碰撞的径向膨胀流.发现丰中子系统¹²⁴Sn+¹²⁴Sn的径向膨胀流系统性地小于系统¹²⁴Ba+¹²⁴Ba的径向膨胀流.同时发现这种差别主要来自于核子–核子碰撞截面的同位旋相关性而几乎与对称能无关.     

同位旋相关的Boltzmann-Langevin方程及新核素19Na产生截面的研究

介绍了一种同位旋相关的输运方程,研究了在入射能量为28.7和6 0. 0MeV/u时 12C+ 12C的反应,对模型进行检验,发现计算结果较好地符合实验结果,说明了方程的可靠性. 利用该模型研究了在入射能量为28.7MeV/u下反应系统 17 -20,22Ne+ 12C中核素 19Na的产生截面,发现缺中子核引起的反应,具有更大 19Na的产生截面,为新核素的探测找到了理论依据.     

轻系统多重碎裂的同位旋效应

利用同位旋相关的量子分子动力学模型,对⁴⁰Ca+⁴⁰Ca和⁴⁰Ar+⁴⁰Ar系统在不同入射能量时,同位旋效应对多重碎裂的影响进行了讨论.低能区的多重碎裂由于多种同位旋相关的因素相互抵消,因此多重碎裂的同位旋效应不明显.随着能量的增加,同位旋相关的截面造成多重碎裂的明显差别.     

Selective CO methanation over amorphous Ni-Ru-B/ZrO2 catalyst for hydrogen-rich gas purification

Amorphous Ni-Ru-B/ZrO₂ catalysts were prepared by chemical reduction method. The effects of Ni-Ru-B loading and Ru/Ni mole ratio on the catalytic performance for selective CO methanation from reformed fuel were studied, and the catalysts were characterized by BET, ICP, XRD and TPD. The results showed that Ru strongly affected the catalytic activity and selectivity by increasing the thermal stability of amorphous structure, promoting the dispersion of the catalyst particle, and intensifying the CO adsorption. For the catalysts with Ru/Ni mole ratio under 0.15, the CO methanation conversion and selectivity increased significantly with the increasing Ru/Ni mole ratio. Among all the catalysts investigated, the 30 wt% Ni-Ru-B loading amorphous Ni₆₁Ru₉B₃₀/ZrO₂ catalyst with 0.15 Ru/Ni mole ratio presented the best catalytic performance, over which higher than 99.9% of CO conversion was obtained in the temperature range of 230°C～250°C, and the CO₂ conversion was kept under the level of 0.9%.     

中能重离子碰撞中的碰撞参数研究

在入射能量E为40和100MeV/u时,对¹¹²Sn+¹¹²Sn和¹²⁴Sn+¹²⁴Sn两个反应系统在不同碰撞参数下进行了同位旋相关的量子分子动力学模型计算,系统研究了阻塞率、线性动量转移、荷电粒子多重性、轻荷电粒子多重性、中子多重性以及束缚核总电荷Z_bound随碰撞参数的变化规律,结果表明,中子多重性对碰撞参数的依赖在两个能量下都存在着明显的同位旋效应,Z_bound在E为40MeV/u时存在着同位旋效应.同时讨论了在较低和较高能量时如何更合理地确定反应事件的碰撞参数.     

中能重离子碰撞中同位旋相关核子–核子碰撞截面的灵敏探针

基于重质量弹核(放射性核或稳定核)打轻质量靶核的逆运动学效应,即反应产物主要集中在小角度的优点,利用同位旋相关的量子分子动力学模型,探寻了对于中能重离子碰撞过程中同位旋效应灵敏的物理观测量.计算表明,在入射能量约大于80MeV/u能区,中等质量碎片多重性随发射带电粒子总数之间的演化是提取介质中同位旋相关的核子–核子碰撞截面的灵敏物理量.     

中能重离子碰撞中的局域平衡讨论

在BUU框架下,讨论了中能重离子碰撞过程中的平衡过程,以及相关的物理量,如集体流、温度、化学势.研究发现,一定时间以后达到局域平衡,且中心区域最先达到平衡,同时周边碰撞时也发现存在局域平衡.平衡时温度为5一7MeV.     

中能重离子碰撞中同位旋相关核子–核子碰撞截面的可能观测量

利用同位旋相关的量子分子动力学研究和寻找提取中能重离子碰撞多重碎裂中同位旋相关核子–核子碰撞截面的可能观测量.计算结果表明,在多重碎裂过程中中等质量碎片多重性与带电粒子总数之间的关联是在所选能区提取介质中同位旋相关核子–核子碰撞截面的灵敏观察量.应用重质量弹核打轻质量靶核具有反应产物向前角发射这一逆反应效应,可以在有限探测器条件下与实验相结合提取介质中同位旋相关的核子–核子碰撞截面.     

Higher order bulk characteristic parameters of asymmetric nuclear matter

The bulk parameters characterizing the energy of symmetric nuclear matter and the symmetry energy defined at normal nuclear density ρ0 provide important information on the equation of state (EOS) of isospin asymmetric nuclear matter. While significant progress has been made in determining some lower order bulk characteristic parameters, such as the energy E0(ρ0) and incompress ibility K0 of symmetric nuclear matter as well as the symmetry energy Esym(ρ0) and its slope parameter L, yet the higher order bulk ...