Simulation of the Lanzhou Penning Trap LPT

The LPT (Lanzhou Penning Trap) is under construction and its task is to perform direct mass measurement of fusion-evaporation residues and if possible for heavy isotopes. Detailed simulations have been done for a good understanding to the ion’s movement and mechanics in the trap. The optimization of the LPT is also performed based on the simulation. With a scale of 0.5 mm per grid used in the simulation and many other limitations a highest mass resolution has been achieved to be 1.9×10-5. An unexpected behaviour in the simulation related to magnetron motion has been found.     

A Facile Synthesis of Indole-based Conjugated Derivatives

A novel synthetic method was developed for the preparation of indole-based conjugated derivatives with satisfied yields. By applying this strategy, a series of new compounds were prepared conveniently. All the obtained new indole derivatives were characterized by spectroscopic analyses, giving satisfactory data corresponding to their expected molecular structures.     

PuO2颗粒对自发α射线的能量自吸收效应评估研究

构建PuO₂颗粒状α发射体的球体几何模型,采用蒙特卡罗和射程经验公式模拟计算α射线在PuO₂颗粒中的射程能量关系式及α射线从PuO₂颗粒表面出射的能谱分布,研究因PuO₂颗粒对自发α射线的能量自吸收效应导致的对人体内照射剂量评估的影响。研究结果表明,PuO₂粒径越大,其对自发α射线的能量自吸收效应越明显,内照射剂量的修正效果越好;当PuO₂粒径在2 μm以上时,内照射剂量的修正效果大于5%。本研究的结果对吸入放射性物质所致人体内照射剂量的准确估算有重要的参考价值,并可应用于放射性核素肿瘤治疗等领域的微剂量学研究。A sphere geometry model for plutonium oxide-based alpha emitter was setup.The range of alpha particle in plutonium oxide pellet versus its energy and the spectral distribution of alpha particle emerging from the emitter surface were calculated using Monte Carlo method combined with the empirical formula of range.The internal radiation dose resulted by self-absorption effect of α-rays emitted spontaneously in plutonium oxide was investigated accordingly.The result shows that the larger particle size the plutonium oxide-based alpha emitter has,the more obvious the self-absorption effect is and the better the correction effect of the intake absorbed dose that effects on human lung has.For plutonium oxide pellet with its particle size exceeding 2 μm,the correction quantity is expected to be larger than 5%.Our work is beneficial for a precise evaluation of internal radiation dose induced by inhaled radioactive material and microdosimetry study in radionuclide tumor therapy.     

两个二阶非线性光学高分子的合成与性能：改善高分子光学非线性-透明性矛盾的尝试

通过后功能化反应将两个新的非线性光学发色团（1和2）分别作为侧链引入聚芳醚砜主链,得到两个新的非线性光学高分子（P1和P2）。这两个发色团（1和2）被设计为含有相同的电子给体（二烷基氨基）和相同的电子受体（TCF）,但含有不同长度的共轭桥,即2包含一个组合共轭桥（苯基二氮烯 + 苯乙烯）,而1的共轭桥要短得多（仅为苯乙烯）。研究了P1和P2的线性和非线性光学性质。与P1相比,P2在呈现出相近的非线性光学系数（d₃₃）的同时异乎寻常地达到了更好的光学透明性（最大吸收波长蓝移16 nm）。结果表明：组合共轭桥结构的引入对于在非线性光学高分子的非线性-透明性之间达到某种平衡起到了良好作用。     

Convenient Synthesis and Enhanced Second-order Nonlinear Optical Property of a Novel Hyperbranched Polymer

A novel hyperbranched polymer （3） was prepared by copolymerization of tri-aldehyde moieties with azo chromophores having two active methelene groups, from ＂A2＋B3＂ approach based on simple Kneovenagel reaction. For comparison, its analogue linear polymer （5） was also synthesized. The two polymers are soluble in common organic solvents, and exhibit good thermal stability. Interestingly, the hyperbranched polymer demonstrates dramatically enhanced second-order nonlinear optical property with comparison to its linear analogue.     

加速器驱动次临界系统散裂靶参数优化计算

采用国际开源程序包Geant4,构建高能质子束轰击加速器驱动次临界系统(ADS)散裂靶的物理模型,模拟计算质子轰击液态金属铅、铅-铋合金和汞靶的泄漏中子谱分布,以及计算不同能量质子对应的铅靶泄漏中子产额和轴向积分分布,获得1 Ge V质子对应的铅圆柱靶优化参数,考虑入射质子的利用率和整个堆芯的体积质量,优化靶半径范围为16～24 cm,靶高为100 cm,相关研究结果可为(ADS)散裂靶的物理和工程设计提供理论依据。     

类氢O、N离子入射Al表面俘获电子布居几率的理论与实验研究

利用“二态矢量模型”详细研究了高电荷态O⁷⁺,N⁶⁺离子入射Al表面时中间里德伯态的形成过程,给出了电子被俘获至不同量子数(n A=2-7)的几率,以及电子俘获至里德伯态最可能的离子-表面距离.计算结果表明,较大的主量子数nA对应较小的里德伯态几率,因此O⁷⁺,N⁶⁺离子入射Al表面时辐射的X射线主要来源于较小的n A至基态的退激.为了验证计算结果,测量了O⁷⁺,N⁶⁺离子入射Al表面的X射线发射谱,并运用FAC程序计算了不同高里德伯态退激到基态的跃迁能(np–1s).实验测量到O,N的K-X射线峰,其特征峰的中心值接近主量子数n=2至n=1的跃迁能,说明发射的X射线主要来源于2p–1s的跃迁,与“二态矢量模型”理论计算的几率一致.     

超重核研究谱仪的RFQ冷却聚束器RFQ1L

介绍了超重核研究谱仪中RFQ冷却聚束器RFQ1L的结构和运用SIMION程序对离子的冷却、聚束、引出和撇气过程的模拟情况。 模拟显示: 通过仔细选择工作点就完全可以把经过充气反冲质量分离器分离后的低品质束流转化为斑点小、发射度小和能量单一的高品质束流， 为紧接其后的磁铁和激光高效率分析提供条件。The structure and the simulation results about the cooling，bunching，extraction and skimming of the RFQ cooler and buncher RFQ1L， which is an important part of the being built super heavy nuclide research spectrometer， have been introduced. It shows that， by careful choice of its working point， we can obtain an ion beam with small beam spot， small emittance and mono energy， which can satisfy the requirements of the successive analyses by dipole and laser with high efficiencies.     

A New Approach to C60-Containing Polyphosphazenes by Polymerization of Phosphonitrile Chloride Trimer in the Presence of C60

A novel synthetic strategy was developed to prepare polyphosphazenes containing C60 moieties. Thus, the phosphonitrile chloride trimer underwent thermal ring-opening polymerization （ROP） in the presence of C60 molecules to yield the reactive macromolecular intermediate, C60-containing poly（dichlorophosphazene）. And then, the other groups could be linked to the phosphazene backbone by nucleophilic substitution reaction of the chlorine atoms in this intermediate to produce a series of C60-containing polyphosphazene. The polymer exhibits good solubility in common organic solvents and is thermally stable.     

Simulation of the Lanzhou Penning Trap LPT

The LPT (Lanzhou Penning Trap) is under construction and its task is to perform direct mass measurement of fusion-evaporation residues and if possible for heavy isotopes. Detailed simulations have been done for a good understanding to the ion's movement and mechanics in the trap. The optimization of the LPT is also performed based on the simulation. With a scale of 0.5 mm per grid used in the simulation and many other limitations a highest mass resolution has been achieved to be 1.9×10^－5. An unexpected behaviour in the simulation related to magnetron motion has been found.