α preformation and penetration probability for heavy nuclei

The α preformation factor and penetration probability have been analyzed for even--even nuclei of Po, Rn, Ra using experimental released energies and α decay half-lives in the frame of the double folding model. It is shown that N=126 is a neutron magic number from α preformation and shell effects play an important role in α preformation. The closer the nucleon number is to the magic number, the more difficult α formation in the parent nucleus is. The preformation factor can supply information on the nuclear structure and the penetration probability mainly determines α decay half-life.     

基于摩擦耗散的石墨/WC-Ni干摩擦下磨损定量及预测

从摩擦耗散的角度研究干摩擦下石墨/WC-Ni配副磨损与摩擦副摩擦耗散能量之间的规律，获得了石墨磨损与配副摩擦耗散功率之间的关系，结果表明石墨干摩擦下的磨损率与配副的摩擦耗散功率呈显著的线性关系. 单一和组合工况磨损预测试验表明:石墨磨损模型能够准确地预测不同工况下石墨的磨损量，预测结果和实际测量结果符合. 干摩擦下石墨磨损率与摩擦耗散功率之间的定量关系，物理意义明确，使用方便，结果可靠，研究结果具有重要的理论和工程应用价值.      

强脉冲电子束辐照材料表面形貌演化的模拟

在回顾和总结强脉冲电子束表面改性实验的基础上, 利用有限元数值计算方法对强脉冲电子束辐照铝和304不锈钢产生的温度场进行模拟, 给出了靶的近表面区域流体状态存在的特征尺度和特征时间, 并对不同材料特性下熔坑的产生原因进行了讨论. 采用两相流模型, 通过水平集方法和有限元方法结合的计算流体力学模拟了熔坑和表面突起形貌在表面处于熔融状态下的运动特征, 通过和实验数据相对比, 验证了对于高黏度, 高表面张力的高熔点金属, 表面处于流体状态下的张力驱动效应是熔坑等表面形貌演化的重要原因.     

强流脉冲离子束能量密度分布的红外诊断

强流脉冲离子束在靶上的能量密度分布是其研究和应用的一个重要参数。为了解决现有束流能量密度诊断方法的不足,利用红外成像仪测量靶背面的温度分布,从而建立了强流脉冲离子束能量密度分布的红外诊断方法。对能量密度1J/cm2量级、脉冲宽度为102 ns量级的束流,该方法测量误差好于5%,空间分辨率可达到1~2mm,具有操作简便、成本低的优点,是强脉冲能量沉积分布的一种高效迅速的诊断方法。     

β射线在铝膜中的吸收研究

利用磁谱仪得到不同能量的单能电子束,让这些电子束穿过不同厚度的铝膜,研究不同能量的电子在铝膜中的吸收系数和能损,得出吸收系数与电子能量的经验公式,与已有的吸收系数经验公式进行了比较,测量到的能损和Fluka软件模拟计算的结果进行了对比,观察到它们之间都能够较好地符合。说明该实验测量的数据和得到的质量吸收系数公式是可靠的,对β射线的防护具有重要参考价值,Fluka软件能够用于较高能量电子能损的计算。     

Optical Potential Parameters of Weakly Bound Nuclear System 17F+13C

Elastic scattering angular distributions of the 14^N＋16^O system and the angular distributions of transfer reaction 16^O（14^N,13^C）17^F at ELab=76.2 MeV and 57 MeV have been measured and calculated by means of the exact finiterange distorted-wave Born approximation with the PTOLEMY code. The optical potential parameters for the weakly bound nuclear system 17^F＋13^C have been deduced and applied to analyse the elastic scattering angular distributions of the similar systems 17^F＋12^C and 17^F＋14^N which are taken from literature. The result shows that the transfer reaction with stable projectile and target combination can be used as an alternative method to extract the optical potential parameters for the weakly bound nuclear system.     

Double folding model calculation applied to fusion reactions

The interaction potential between a spherical and a deformed nucleus is calculated within the double-folding model for deformed nuclei. We solve the double folding potential numerically by using the truncated multipole expansion method. The shape, separation and orientation dependence of the interaction potential, fusion cross section and barrier distribution of the system ¹⁶O+¹⁵⁴Sm are investigated by considering the quadrupole and hexadecapole deformations of ¹⁵⁴Sm. It is shown that the height and the position of the barrier depend strongly on the deformation and the orientation angles of the deformed nucleus. These are quite important quantities for heavy-ion fusion reactions, and hence produce great effects on the fusion cross section and barrier distribution.     

重核大集团发射半衰期的计算

重核大集团（¹⁴C-³⁴Si）发射的半衰期在理论上用Wentzel-Kramers-Brillouin近似进行了计算.利用双折叠模型计算大集团和剩余子核间的核相互作用,在折叠积分中选取了密度依赖的、零力程交换项的核子-核子相互作用.计算得到的半衰期和液滴模型结果、系统公式的结果以及实验数据进行了比较,表明目前的计算能够很好地给出重核大集团（¹⁴C-³⁴Si）发射的寿命.这可为重核其他大集团（¹⁵N, ⁴⁶Ar,⁴⁸Ca等）的发射提供可靠的预测. 关键词： 半衰期 双折叠模型 集团发射     

Simulation of beam optics for ~(12)C+~(12)C scattering of RCNP by using Monte Carlo method

The Monte Carlo method is used to simulate the beam optics of the WS beam line of RCNP, Osaka University in order to know the effect of collimators on the beam line to control the beam spot. According to the simulation, we do not need to use the collimator to cut the beam and the beam angular resolution can be better than 0.05° in achromatic mode. In the present paper, the actual beam condition during the beam adjustment is listed. The accelerator can provide a 12 C beam in achromatic mode and the angular resolution σ=0.7775 mrad ±0.0030 mrad.     

Systematic analysis of fusion barrier heights and positions for proton projectiles using the single folding model

The nuclear potentials between protons and different target nuclei are calculated by using the single folding model with the density-dependent nucleon-nucleon interaction.The fusion barrier heights and positions for proton projectiles fusing with different target nuclei with masses from 51 amu to 139 amu are systematically shown,with charge numbers and root-mean-square radii of the interacting nuclei.The parameterized formulas for the fusion barrier height and position are obtained for proton projectile fusing with the different nuclei.The calculated results of parameterized formulas are compared to empirical values,as well as those of the proximity potential and AkyüzWinther(AW) potential.It is shown that the calculated results agree perfectly with theirs.The parameterized formulas can reproduce the exact barrier heights and positions for proton fusion systems.