Evolutional Properties of Localized Excitations for Generalized Broer-Kaup System in （2＋1） Dimensions

Using a special Painleve-Baecklund transformation as well as the extended mapping approach and the linear superposition theorem, we obtain new families of variable separation solutions to the （2＋1）-dimensional generalized Broer-Kaup （GBK） system. Based on the derived exact solution, we reveal some novel evolutional behaviors of localized excitations, i.e. fission and fusion phenomena in the （2＋1）-dimensional GBK system.     

脉冲堆有限裂变链长的数学期望值分析(英文)

讨论了在一个增殖系统引发一个持续裂变链所需要的平均中子数。在点堆模型基础上, 考虑了在 t0 时刻系统引入一个源中子, 在 t 时刻产生 n 个中子的概率(n, t0, t), 推导了概率生成函数 G(z; t0, t)所满足的偏微分方程, 并得到了近似解。用近似解计算了Godiva II脉冲堆的有限裂变链长数学期望值, 有限裂变链期望值反比于脉冲堆的反应性。     

重离子熔合反应与双核模型

简单介绍了兰州-北京-吉森合作组对合成超重核的重离子反应进行的初步研究。研究的重点是熔合阶段的反应机制。在原有双核模型的基础上做了一些改进,把耗散相对运动过程与核子转移过程耦合起来,从更微观的角度来描写双核系统向全熔合复合核的演化。在双核过程中的每一步求解主方程,不对驱动势做谐振子近似。同时,还探讨了原子核形变与相对取向对驱动势的影响,存活几率与复合核蒸发中子的奇偶效应,以及入射道中原子核非弹性激发对俘获截面的影响等。In recent years, the Lanzou-Beijing-Giessen collaboration has studied the heavy ion reactions which are lead to the formation of super-heavy nuclei. The study emphases the mechanism of the fusion stage of the reactions. Based on the so called Di-nuclear System Model, some improvements have been made. The main points are the coupling of the dissipation of relative motion energy, angular momentum with nucleon transfer, and solving the Master equation in every step of the nucleon transfer with exact driving potentials, in order to describe the evolution of the system more microscopically. At the same time, we also discussed the effects of nuclear deformation and their relative orientation on the driving potentials, and studied the survive probability of the compound nuclei and its old-even effects, as well as the influence of inelastic excitations of nuclei in entrance channels to the capture cross sections.     

符合计数在钚的属性测量中的应用研究

中子符合计数在核材料认证和管理中有着广泛的应用．系统阐述了中子符合计数的基本原理,对“点模型”公式作了推导．利用MCNP4B程序实现了中子符合计数的数值模拟.Neutron coincidence counting is widely used in the authentication and management of nuclear material. The basic principles of coincidence counting and the derivation of "point model" formulae of "point model" are introduced in this paper. The numerical simulation of the coincidence counting is implemented by use of the MCNP4B package.     

混合评价核数据库HENDL1.0/MG/MC研制

根据世界几个主要核评价数据库,如ENDF/B 6(美国)、JEF 2.2(欧盟)、JENDL 3.2(日本)、BROND 2.2(俄罗斯)、CENDL 2.1(中国)和FENDL 2(IAEA/NDS),兼顾聚变、裂变以及聚变 裂变次临界混合堆设计研究的多种需要,经过甄别、筛选,最后集成为包含213个核素的基本评价文件,名为HENDL1.0/E的核评价数据库.在此基础上,利用目前流行的群常数加工程序系统NJOY和输运截面制备程序TRANSX制作两套用于中子或/和光子输运计算的输运截面工作库:①参考Vitamin J能群结构制作了175群中子和42群光子、中子 光子耦合多群工作数据库HENDL1.0/MG,可用于离散纵标Sn法程序计算;②连续能群结构、紧凑ENDF(ACE)格式中子截面库HENDL1.0/MC,可用于蒙特卡罗方法输运计算,如MCNP.另外还制作了可用于燃耗(嬗变)计算的燃耗库BURNUP.LIB和响应函数库RESPONSE.LIB两个专用数据库.同时,也对HENDL1.0综合评价核数据库的有效性进行了抽样测试、基准检验和初步确认. A Hybrid Evaluated Nuclear Data Library(HENDL) named as HENDL1.0 has been developed by Fusion Design Study (FDS) team of Institute of Plasma Physics, Academia Sinica (ASIPP) to take into account the requirements in design and research relevant to fusion, fission and fusion-fission sub-critical hybrid reactor. HENDL1.0 contains one basic evaluated sub-library naming HENDL1.0/E and two processed working sub-libraries naming HENDL1.0/MG and HENDL1.0/MC, respectively. Through carefully comparing...     

Study of Survival Probability of Super Heavy Nuclei

The survival probability of super heavy nuclei produced in cold fusion reactions is studied by using the standard Fermi gas level density formula and analyzed with fission and neutron evaporation characteristics predicted in different theoretical models. The level density formula used in this letter suppresses the ratio of neutron emission width to fission width, Гn/Гf. The dependence of Гn/Гf on the saddle point level density parameter and excitation energy is also investigated.     

Hobson文科物理教材选载⑦——能量的挑战

译者说明:这次选登的是Hobson书的第17章,讨论能源问题(这部分篇幅较长,将分2期刊出--编者).能源问题是人类面临的一个严重问题.它既影响发展,又影响环境.     

丰中子核108Ru的集体带结构

通过对重核²⁵²Cf自发裂变产生的瞬发γ谱的测量, 对丰中子核¹⁰⁸Ru的能级结构进行了研究. 基带、单声子γ振动带和一个二准粒子带分别得到了确认和扩展, 同时识别了一个新的边带, 初步认定为二声子γ振动带. TRS模型计算表明¹⁰⁸Ru核具有三轴形变，其形变参量为β₂～0.29, γ=－22°. 推转壳模型的计算结果表明¹⁰⁸Ru核基带回弯是由h_11/2轨道的一对中子发生角动量的顺排所致. 对二准粒子带的组态特性也进行了讨论.     

Measurement of Neutron Fluxes and Spectra during the NT-TBM Operation of CN HCSB

Neutronics measurement system provides neutron fluxes and spectra at the locations of beryllium multiplier and tritium breeder during the operation of the NT-TBM （D-D and D-T phase in ITER）. This is important for studying and assessing capabilities of beryllium multiplier and tritium breeder in the China helium cooled solid breeder （CNHCSB）. A special neutron diagnostic system has been proposed that allows to measure neutron fluxes and spectra without interrupt the operation of ITER. This system includes encapsulated foil activation analysis, micro-fission chamber detectors （MFC）, and a compact neutron spectrometer using natural diamond detector （NDD）.