Beam dynamics simulation of HEBT for the SSC-linac injector

The SSC-linac (a new injector for the Separated Sector Cyclotron) is being designed in the HIRFL (Heavy Ion Research Facility in Lanzhou) system to accelerate ²³⁸U³⁴⁺ from 3.72 keV/u to 1.008 MeV/u. As a part of the SSC-linac injector, the HEBT (high energy beam transport) has been designed by using the TRACE-3D code and simulated by the 3D PIC (particle-in-cell) Track code. The total length of the HEBT is about 12 meters and a beam line of about 6 meters are shared with the exiting beam line of the HIRFL system. The simulation results show that the particles can be delivered efficiently in the HEBT and the particles at the exit of the HEBT well match the acceptance of the SSC for further acceleration. The dispersion is eliminated absolutely in the HEBT. The space-charge effect calculated by the Track code is inconspicuous. According to the simulation, more than 60 percent of the particles from the ion source can be transported into the acceptance of the SSC.     

一维梯形蓝色荧光磺酸锶配位聚合物

The reaction of 3-carboxy-4-hydroxybenzenesulfonic acid with SrCl₂·6H₂O yields one-dimensional double-chain coordination polymer {[Sr(H₂SSA)₂(H₂O)₄]·2H₂O}_n (1), which displays strong blue fluorescence emission (λ_max=423 nm) in the solid-state at room temperature. Crystal data for 1: Triclinic, space group P1, a=0.688 48(2) nm, b=0.706 86(2) nm, c=2.474 22(7) nm. α=96.458(2)°, β=90.796(2)°, γ=108.628 0(10)°, V=1.132 19(6) nm³, Z=2, 16 575 unique data (θ_max=25.99°), R=0.021 1 (4 411 [I≥2σ(I)] reflections), wR=0.052 5 (all data), ρ_max=0.881 e·nm^-3. CCDC: 279677.     

TiO_2-SiO_2纳米粒子的合成及二级散射光谱法测定核糖核酸

采用溶胶-凝胶法制备了TiO2-SiO2纳米粒子.通过X-射线衍射谱、透射电子显微镜等对纳米粒子进行了表征.研究了TiO2-SiO2纳米粒子与核糖核酸(RNA)的相互作用,建立了基于纳米粒子与RNA吸附反应,二级散射光谱法测定痕量RNA的新方法.方法的线性范围是0.005～5 mg/L; 检出限为1.46 μg/L.方法用于RNA合成样品的测定,回收率为99.4%～103.9%;相对标准偏差为019%～0.24%.     

聚对苯二甲酸乙二酯溶剂诱导结晶研究 Ⅲ．溶剂对聚对苯二甲酸乙二酯玻璃化转变温度的影响

应用动态力学方法测定了聚对苯二甲酸乙二酯ＰＥＴ／溶剂体系的粘弹谱，从实验上证实溶剂对ＰＥＴ进行增塑，使其玻璃化转变温度降低，导致ＰＥＴ在低于通常的结晶温度下结晶，甚至在室温便进行结晶，证明溶剂诱导结晶是由于玻璃化转变温度降低的机理是正确的，可接受的．     

含孔缺陷石墨烯纳米条带的电学特性研究

本文系统地研究了不同形状(三方、四方及六方) 的孔缺陷对锯齿形石墨烯纳米条带电学特性的影响. 结果表明: 孔缺陷形状对于石墨烯纳米条带的电导及电流特性影响显著, 其可能源于不同形状的孔缺陷边界对于电子散射的不同; 另外, 当缺陷悬挂吸附氢或氮原子, 将引起孔缺陷形状改变, 因此不同孔缺陷吸附对于石墨烯纳米条带的电学特性的影响也各不相同. 本研究将为石墨烯基电子器件失效分析及石墨烯孔结构器件设计提供有价值的理论指导. 关键词： 石墨烯 孔缺陷 电学特性     

杂多化合物膜的制备及催化作用

Heteropoly compounds (HPC), a kind of polyoxometallates, with their strong acidity and oxidative ability, are good homogeneous and heterogeneous catalysts in both acid-catalyzed and selective oxidation reactions, and have been widely used in petroleum and fine chemical industries. Owing to the diversity in their composition and structure, the catalytic properties of HPC can be altered in a wide range. Among them, the heteropolyanions with Keggin structure have been studied by far the most,especially on their applications in heterogeneous catalysis. However, since they are thermally unstable at high temperatures, their utilization in this field has been restricted. In the last ten years, inorganic membranes have been proved to be beneficial to heterogeneous catalytic processes for their high selectivity and good heat-conductivity. And the sol-gel method, one of the most common approaches to prepare inorganic membranes, is becoming mature. Here a sol-gel method to prepare a porous HPC membrane is reported. The catalytic performance of the membrane was tested through a model reaction, the selective oxidation of t-BuOH.     

薄层色谱法分离紫杉醇和三尖杉宁碱

建立了用薄层色谱分离紫杉醇和三尖杉宁碱的方法.方法中以正己烷-二氯甲烷-甲醇-三乙胺(体积比4.5∶3.5∶0.5∶1.0)四元体系为展开剂,在硅胶薄层板上成功地分离了紫杉醇和三尖杉宁碱,所得斑点清晰、无拖尾.同时以该体系为展开剂,使用薄层色谱法指导分离提取紫杉醇和三尖杉宁碱过程中反相色谱流分的合并,方法快速、简单、成本低,取得了满意的结果.     

胶束作为纳米反应器的研究进展

纳米反应器作为一种新型的制备纳米粒子及重要功能分子的手段,其技术在许多领域受到广泛重视.与常规意义上的化学反应器有所不同,纳米反应器是指反应所处的受纳米尺度调制的介观环境,如反应的介质、载体、界面等等.纳米反应器一般分成两类,一种是在分散相中能自组装的分子,形成有序聚集体,如胶束、囊泡,在聚集体的内部制备纳米粒子或材料;另一种是天然存在或合成的分子,如纳米管、树枝聚合物,利用分子特有的结构或孔隙作为纳米反应器.本文主要介绍了胶束、胶束作为纳米反应器的分类;重点讨论了分子及聚合物胶束作为纳米反应器的特点,并对其研究进展及前景进行总结和展望.     

电致发光显示

电致发光具有固体平板化的优点，用它可做成大面积和任意形状的发光图形．不仅可以做成大面积数字与字符显示器件、模拟显示器件，更重要的是可以做成全固体平板化的计算机终端显示器，从而做成便携式计算机、大面积的会务信息显示器、车站和机场时刻显示器等．全固体平板化的“黑白”电视机已成为现实，“挂壁”式彩色电视机的研究也取得了明显进展，用固体化的平板显示器件代替阴极射线管已成为科技发展的必然趋势．     

Ru掺杂SnO2半导体固溶体的电子结构研究

运用基于密度泛函理论的第一性原理方法,建立了SnO₂以及不同比例Ru掺杂的SnO₂超胞模型,在对其进行几何优化后计算了Sn_1-xRu_xO₂(x=0,1/16,1/12,1/8,1/6,1/4,1/2)半导体的电子结构,并讨论了其晶格参数、电荷密度、能带结构和态密度(包括分态密度)等性质。结果表明,掺杂后,晶格参数随掺杂量的增加线性减小,与实验值的偏差在4%以内;掺杂后,在费米能级处可以提供更多的填充电子,使得电子跃迁至导带更容易,固溶体的导电性增强。为Sn_1-xRu_xO₂固溶体电极材料的发展和应用提供了理论基础。