Status of CSNS H- ion source

A new H^- ion source has been installed successfully and will be used to serve the China Spallation Neutron Source (CSNS). In this paper, we report various components of the ion source, including the discharge chamber, temperature, cooling system, extraction electrodes, analyzing magnet, remote control system and so on. Compared to the previous experimental ion source, some improvements have been made to make the ion source more compact and convenient. In the present arrangement, the Penning field is generated by a pair of pole tip extensions on the 90° analyzing magnet instead of by a separate circuit. For the remote control system, F3RP61-2L is applied to the accelerator online control system for the first time. In the running of the ion source, a stable pulse H^- beam with a current of 50 mA at an energy of 50 keV is produced. The extraction frequency and pulse width is 25 Hz and 500 μs, respectively. Furthermore, an emittance scanner has been installed and measurements are in progress.     

D4型量子包络代数的Gelfand-Kirillov维数

本文研究了D₄ 型量子包络代数的Gelfand-Kirillov 维数的计算问题. 利用文献[1] 中给出的Gelfand-Kirillov 维数的计算方法和文献[2] 中给出的D₄ 型量子包络代数的Groebner-Shirshov 基计算了D₄型量子包络代数的Gelfand-Kirillov 维数, 得到的主要结果是D₄ 型量子包络代数的Gelfand-Kirillov 维数为28. 希望此结果为计算D_n型量子包络代数的Gelfand-Kirillov 维数提供一些思路.     

一道最优化问题的解法赏析

1 例题及解答方法 例 已知铁路上A,B两站的距离是100,某地C到铁路的垂直距离为20,AC,BC之间为公路,且铁路货运与公路货运的费用之比为1:2.能在铁路上修建一个货站M,C、M之间为公路,使从B站经M站再到C站的运价最低吗?     

Thermal analysis of the CSNS H~- ion source

There are two cooling systems to maintain the thermal stability of the CSNS H- ion source during its operation:Air-cooling in the source body of the discharging chamber and water-cooling in the flange on which the discharging chamber is installed.The optimal cooling parameters to ensure the operation of the H- ion source are determined through a thermal analysis.In addition,a transient analysis is also performed to know exactly the transient temperature variation during the whole 40 ms period of the pulsed ...     

碘离子选择电极催化动力学法测定钒(V)的研究

本文介绍用碘离子选择电极催化电势动力学法对测定钒(Ⅴ)进行的研究,发现去氢抗坏血酸是钒(Ⅴ)催化BrO_3-氧化I~-体系的一种良好的活化剂,详细地研究了各种因素对测定的影响,找出了测定钒(Ⅴ)的较佳条件。该法测定钒(Ⅴ)浓度的线性范围很宽,检测限为2×10~(-10)mol/l,灵敏度比文献报道的高3个数量级。对几种离子的干扰进行了试验,柠檬酸可以有效地掩蔽这些离子的干扰。此法曾应用于测定自来水和头发中的钒,得到了较好的结果。     

Synthesis of Schiff Base-type Liquid Crystalline Crown Ethers Containing Dibenzo-18-Crown-6 Unit

The synthesis and characterization of novel Schiff base liquid crystalline crown ethers prepared from the intermediates 4-(4‘-alkoxylbiphenyl-4-carbonyl)benzaldehyde, cis- and trans-4,4‘-diaminodibenzo-18-crown-6 are described. The structure of these compounds have been well characterized by elemental analysis, IR, ^1H NMR and MS spectroscopy. The liquid-crystalline behavior of these compounds was also inverstigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) with a heating stage and polarimetric analysis.     

用传感器测量重力加速度

用传感器测量重力加速度徐瑞堂，吴甫秀（江西师范大学物理系南昌３３００２７）由南京工学院研制，扬州无线电二厂生产的ＹＥ５８５８双积分电荷放大器（简称ＹＥ５８５８）和ＹＥ１４１０５低频压电式加速度传感器（简称ＹＥ１４１０５）配接使用，可测量航空、机械、车...     

在硅晶体中由螺位错引起的电子散射

本文讨论硅晶体中由〈110〉螺位错引起的电子散射,用紧束缚近似只考虑s电子和p电子。用长波近似只考虑Γ附近的电子散射。此散射近似地服从基尔霍夫-惠更斯形式的积分方程。用规范变换和格林函数方法解出了散射方程。确认了在硅复杂能带的情况下也同单一能带的情况一样,在位错的下游侧出现电子波播及不到的影子。 关键词：     

低能、强流质子圆形加速器共振现象的模型研究

详细讨论了低能强流质子圆形加速器中质子穿越整数及半整数共振点的现象.通过对注入能量为1MeV,加速电压分别为1kV和2kV时的模拟计算,确定了束流安全穿越整数及半整数共振点对二极铁和四极铁加工误差的要求.     

大型FFAG磁铁的2维POISSON设计

 为减小边缘场效应，大型固定磁场交变梯度（FFAG）磁铁的磁场分布由修整线圈和磁极形状两者共同来实现。通过2维POISSON模拟计算，确定了修整线圈电流和位置的分布以及磁极形状, 得到了局域磁场梯度指数与设计值之间的最大差异只有0.5％的磁场分布。为提高POISSON模拟计算的效率，POISSON输入文件中有关线圈电流和位置、磁极形状的输入和调整由程序自动完成。