Ground State Properties of Superheavy Nuclei in Macroscopic-Microscopic Model

The ground state properties of superheavy nuclei are systematically calculated by the macroscopic- microscopic （MM） model with the Nilsson potential. The calculations well produced the ground state binding energies, α-decay energies, and half lives of superheavy nuclei. The calculated results are systematically compared with available experimental data. The calculated results are also compared with theoretical results from other MM models and from relativistic mean-field model. The calculations and comparisons show that the MM model is reliable in superheavy region and that the MM model results are not very sensitive to the choice of microscopic single-particle potential.     

Topological Aspects of Solitons in Ferromagnets

Two kinds of topological soliton （skyrmion and magnetic vortex ring） in ferromagnets are studied. They have the common topological origin, a tensor Hαβ = n→·（δαn→×βδn→）, which describes the non-trivial distribution of local orientation of magnetization n→ at large distances in space. The topological stability of skyrmion is protected by the winding number. Knot-like topological defect as magnetic vortex rings is also studied. On the assumption that magnetic vortex rings are geometric lines, we present their δ-function distribution in ferromagnetic materials. Furthermore, it is briefly shown that Hopf invariant is a proper topological invariant to describe the topology of magnetic vortex rings.     

RF deflecting cavity design for bunch length measurement of photoinjector at Tsinghua University

RF deflecting cavity can be used for bunch length measurement and is designed to diagnose the beam produced by the photocathode electron gun which was built at Tsinghua University for the Thomson scattering experiment. Detailed discussion and calculation for measuring the 3.5 MeV bunch and another with further acceleration to 50 MeV, which is under development, are presented. A standing-wave deflecting cavity working at 2856 MHz is designed and the power feeding system has been planned.     

Common Features in Electronic Structure of the Oxypnictide Superconductors from Photoemission Spectroscopy

High resolution photoemission measurements are carried out on non-superconducting LaFeAsO parent com- pound and various superconducting RFeAs（O1-ZFx） （R=La, Ce and Pr） compounds. It is found that the parent LaFeAsO compound shows a metallic character. By extensive measurements, several common features are identified in the electronic structure of these Fe-based compounds： （1） 0.2 eV feature in the valence band, （2） a universal 13-16 meV feature, （3） near EF spectral weight suppression with decreasing temperature. These uni- versal features can provide important information about band structure, superconducting gap and pseudogap in these Fe-based materials.     

35kJ直接冷却高温超导储能磁体

介绍了直接冷却高温超导储能磁体的基本结构,分析了磁体的电磁特性,分析结果表明,磁体电磁设计中采用端部两对饼并联的方式,削弱了磁体端部磁场径向分量,提高临界电流,磁体表现了较好的电磁特性;仿真了磁体与电力系统进行功率交换时的热特性,仿真结果与实验结果两者温度变化总体趋势是一致的;介绍了磁体的冷却实验和磁体系统的动态模拟实验结果.实验结果表明磁体的冷却措施和低温系统的冷却方案是可行的,磁体具有较好的热稳定性.     

制备水溶性CdS量子点的一种物理方法：飞秒激光烧蚀法

用Ti/sapphire飞秒激光系统产生的100fs、800nm激光对置于水中的CdS体相材料进行烧蚀,得到了水溶性CdS纳米粒子。这种纯物理过程保证了无污染的制备环境,从而保证了所合成材料的纯洁性。通过透射电子显微镜、紫外/可见/近红外吸收光谱、室温光致发光谱的方法对CdS量子点的形貌及其光学性质进行了表征。结果表明:利用飞秒激光烧蚀法所制备的CdS量子点可直接分散在水中而且具有粒径小、分布均匀的特点;同时具有较好的胶体稳定性,可在空气中稳定存放6个月以上。飞秒激光烧蚀法所制备的CdS量子点所具有的这些性质使其在生物标记领域引起极大的兴趣,而且也为纳米材料的制备提供了新的思路。     

翻转线圈系统在波荡器积分场测量中的应用

 为了更有效地测量用于上海同步辐射光源波荡器的积分场误差,在已有的伸展线磁测系统的基础上研制了一套翻转线圈磁测系统,该系统的运动控制、数据采集和数据分析处理均可自动完成。在利用这套磁测系统测量3.4×10^-6 T·m磁场积分时获得高于1×10^-6 T·m的测量精度,初步的实验结果表明这套波荡器积分磁场测量系统具有测量精度好、速度快的特点,与已有的伸展线磁测系统、平移线圈磁测系统和霍尔点测系统相比,它更适合于测量波荡器的一、二次场积分和多极场分量。     

空间频率对透射式全息图衍射率的影响

为研究干涉条纹空间频率与透射式全息图衍射率的关系,在相同条件下,拍摄以平面波、发散的和会聚的球面波分别作参考光、物光的透射式全息图,通过实验测量其衍射效率,同时计算了干涉条纹的空间频率。然后以会聚的球面波为物光,平面波为参考光,分别改变入射角和球面波会聚点到记录面的距离制作另外4块透射式全息图,并计算了它们的空间频率,测量了其衍射效率。结果表明：在相同条件下制作透射式全息图时,衍射效率只由空间频率决定,与使用何种参考光和物光无关,空间频率仅随参考光和物光的夹角变化而变化。     

二极管侧面抽运Nd∶YAG 4波长同时输出激光

为了获得1064nm,1319nm,589nm及660nm 4波长激光同时输出,设计了双激光晶体同步声光调Q“T”型复合谐振腔。通过软件模拟与计算,筛选出理想的谐振腔参数,使2波长基频光在大泵浦电流范围内能稳定运转。以KTP晶体和LBO晶体为和频晶体和倍频晶体,在泵浦电流为17A,重复频率为10kHz时,获得了1064nm,1319nm,589nm和660nm 4波长激光输出,最高平均功率分别为150mW,80mW,2.3W和1.7W,同时测得589nm激光和660nm激光的脉冲宽度分别为110ns和130ns。结果表明：使用热稳“T”型复合腔,可以获得4波长激光同时稳定输出。     

高效液相色谱法检测蔬菜中甲萘威残留

本文采用高效液相色谱(HPLC)法检测叶类蔬菜(以菠菜为例)中甲萘威的残留.采用以十八烷基键合硅胶为固定相色谱柱,以甲醇-水=55∶ 45 (V/V)为流动相,用二极管阵列检测器在268 nm波长下检测.菠菜样品采用超声波辅助提取进行前处理,提取液经浓缩后进行HPLC分析.该方法的线性范围为0.50～10.0 mg,k...