质子-核弹性散射的相对论微观光学势分析

本文用基于Walecka模型得到的相对论微观光学势^[1]系统地分析了300MeV以下质子-核的弹性散射实验数据,包括微分截面,分辨本领和自旋转动函数.理论计算结果与实验数据很好地符合,在θ<70°范围内较好地符合实验微分截面,并且能给出自旋有关量的细致结构.结果表明这种简单的模型给出的相对论微观光学势适用于各种靶、E<300MeV的很大能量范围内的核子弹性散射.它可以推广用于核输运理论以及重离子反应中同时考虑核介质与相对论效应.     

巨单极共振和对称能

基于带有混合同位旋标量-矢量非线性耦合的有效拉格朗日量, 在完全自洽的相对论无规位相近似的框架内, 通过单极压缩模式讨论了核物质的不可压缩性. 比较核²⁰⁸Pb,¹⁴⁴Sm,¹¹⁶Sn和⁹⁰Zr实验和计算的巨单极共振能量, 给出了核物质不可压缩系数的取值范围. 新的同位旋标量-矢量非线性耦合软化核物质的对称能, 但无损于基态性质与实验的一致性. 讨论了对称能的软化对巨单极共振的影响.     

用福克-普朗克方程严格解裂变速率问题

本文应用数值方法严格求解二维福克-普朗克(Fokker-Planck)方程,研究在鞍点上的速度分布、坐标和速度的二次矩以及核裂变速率随时间的演变.在相当大的粘滞性范围内,研究核裂变速率与粘滞性的依赖关系,观察到在一定粘滞性下出现裂变速率极大值的现象.对计算的各种结果进行了解释。     

Deformed Potential Energy of Super Heavy Element Z = 120 in a Generalized Liquid Drop Model

The macroscopic deformed potential energy for super-heavy elements Z=120 is determined within a generalized liquid drop model (GLDM). The shell correction is calculated with the Strutinsky method and the microscopic single particle energies are derived from the shell model in an axially deformed Woods-Saxon potential with the same quasi-molecular shape. The total potential energy of a nucleus is calculated by the macro-microscopic method as the summation of the liquid-drop energy and the Strutinsky shell correction. The theory is adopted to describe the deformed potential energies in a set of cold reactions. The neck in the quasi-molecular shape is responsible to the deep valley of the fusion barrier due to shell corrections. In the cold fusion path, the double-hump fusion barrier is predicted by the shell correction and complete fusion events may occur. The results show that some of projectile-target combinations in the entrance channel, such as ^50Ca ^252Fm→120 and 58Fe 244 pu→^302 120 , favour the fusion reaction, which can be considered as candidates for the synthesis of super heavy nuclei Z=120 and the former might be the best cold fusion reaction to produce the nucleus ^302 120among them.     

EXCITATION OF THE DELTA-BARYON WITH DENSITY DEPENDENCE IN QUASIELASTIC ELECTRON SCATTERING

ＥＸＣＩＴＡＴＩＯＮＯＦＴＨＥＤＥＬＴＡ┐ＢＡＲＹＯＮＷＩＴＨＤＥＮＳＩＴＹＤＥＰＥＮＤＥＮＣＥＩＮＱＵＡＳＩＥＬＡＳＴＩＣＥＬＥＣＴＲＯＮＳＣＡＴＴＥＲＩＮＧＷａｎｇＺｉｓｈｅｎｇＭａＺｈｏｎｇｙｕ（ＣｈｉｎａＩｎｓｔｉｔｕｔｅｏｆＡｔｏｍｉｃＥ...     

用相对论Brueckner-Bethe-Goldstone方程研究相对论微观光学位

本文用相对论Brueckner-Bethe-Goldstone(RBBG)方程研究核子-核的相对论微观光学势。核子的复有效质量是通过入射能量为200MeV的质子-~(40)Ca散射数据来确定,由此进一步研究了质子对不同靶核:~(16)O,~(40)Ca,~(90)Zr,~(208)Pb能量范围从160—800MeV的相对论微观光学位。我们用这种微观光学位研究了入射能量为200MeV质子与~(40)Ca的弹性散射,并与唯象相对论光学位计算得到的截面,自旋可观测量进行了比较。     

Relativistic Continuum Random Phase Approximation and Applications I. Formalism

A fully consistent relativistic continuum random phase approximation （RCRPA） is constructed in terms of the Green＇s function technique. In this method the contribution of the continuum spectrum to nuclear excitations is treated exactly by the single particle Green＇s function, which includes also the negative states in the Dirac sea in the no sea approximation. The theoretical formalism of RCRPA and numerical details are presented. The single particle Green＇s function is calculated numerically by a proper product of regular and irregular solutions of the Dirac equation. The numerical details and the formalism of RCRPA in the momentum representation are presented.     

Halo Structure of Nucleus ^23Al

The recently measured reaction cross section of ^23Al is analysed in the Glauber model with an optical limit or few-body approach.It is found that the conventional fixed core-plus-nucleon model for halo nuclei is unable to explain the observed abnormally large reaction cross section of ^23Al by any selection of the halo nucleon configurations.The reaction cross section of ^23Al can be described when the core size is enlarged,although the Coulomb barrier lagely hinders the formation of a halo sturcture for proton-rich nuclei.This is consistent with the case in s-d shell neutron-rich nuclei,where an enlarged core was proposed to explain both the reaction cross section and longitudinal momentum distribution data.     

Nuclear structure around ~(80)Zr

Recent years have witnessed intense activity concerning the study of nuclei with equal numbers of neutrons and protons (N = Z). Exotic properties have been exhibited in the N = Z nuclei, especially in those with atomic masses around 80. In the present paper, the projected shell model(PSM)together with a relativistic Hartree-Bogoliubov (RHB) theory is used to study the nuclear structure near the N = Z line in the mass A ≈ 80 region. For three Zr isotopes 80,82,84Zr, the projected potential energy surfaces an...     

相对论离壳光学势的研究

基于相对论性核子-介子模型,导出了考虑σ、ω介子交换的离壳光学势虚部公式,并利用色散关系讨论了对实部的修正。这些结果可用于有效质量的计算和对光学势行为的分析。