A vertical test system for China-ADS project injector Ⅱ superconducting cavities

To test superconducting cavities, a vertical test system has been designed and set up at the Institute of Modern Physics (IMP). The system design is based on VCO-PLL hardware and the NI Labview software. The test of the HWR010#2 superconducting cavity shows that the function of this test system is satisfactory for testing the low frequency cavity.     

Experimental Study of Natural Convection from Electrically Heated Vertical Cylinders Immersed in Air

Abstract

An experimental study of laminar steady-state natural convection heat transfer from electrically heated vertical cylinders immersed in air has been undertaken. Three stainless steel (316 SS) test sections of different slenderness ratios were employed. Surface temperature profiles along the vertical cylinders were obtained using miniature thermocouples when the cylinders were heated with different power levels resulting in different total wall heat fluxes. After the mandatory corrections for the radiation heat fluxes were made, three correlation equations relating the local Nusselt number Nu_y with the local modified Rayleigh number Ra^* _y and the position-to-cylinder diameter y/d were developed. The correlation equations are valid for Ra^* _y ≤ 2 × 10¹².     

CCD立靶测量系统目标捕获性能研究

在CCD立靶测量系统工作原理的基础上,从CCD的灵敏度与曝光量、背景照度与目标照度、CCD的分辨能力和目标与背景的对比度等几个方面研究CCD立靶测量系统的目标捕获性能,给出了相关的计算方法.特别对暗、小、快目标的全天时捕获,提出了采用激光选通照明的方法来保证系统的捕获率.通过实验验证了计算方法和照明方法的有效性.     

Pedestrian choice behavior analysis and simulation of vertical walking facilities in transfer station

Considering the interlayer height, luggage, the difference between queuing pedestrians, and walking speed, the pedestrian choice model of vertical walking facilities is established based on a support vector machine. This model is verified with the pedestrian flow data of Changchun light-rail transfer station and Beijing Xizhimen transfer station. Adding the pedestrian choice model of vertical walking facilities into the pedestrian simulation model which is based on cellular automata, the pedestrian choice behavior is simulated. In the simulation, the effects of the dynamic influence factors are analyzed. To reduce the conflicts between pedestrians in opposite directions, the layout of vertical walking facilities is improved. The simulations indicate that the improved layout of vertical walking facilities can improve the efficiency of pedestrians passing.     

Constrained optimization of the randomized iterative method

Selection of conditionally optimal parameters of the randomized iterative method for solving large-scale linear systems of equations is considered. The error of this method is analyzed by analogy with the functional Monte Carlo algorithms. For the simple iteration method, the “column” randomization of the matrix is thoroughly analyzed.     

基于整体柱的超灵敏表面增强拉曼检测

本文提出了一种全新的基于整体柱材料的SERS检测方法。通过将探针分子和银溶胶混合后滴加在整体柱上, 我们可以得到浓度低至10-18 mol/L的罗丹明6G(R6G)及10-16 mol/L的对巯基苯胺(PATP)的SERS信号。利用原子力显微镜(AFM)和扫描电镜(SEM)对银溶胶及整体柱材料进行了表征。通过实验结果可以初步推测, 整体柱材料的表面形态和孔结构可以促进银溶胶产生“热点”。     

城市基层党建与社区社会资本生成—基层社区党建的延展效应

与强调纵向协调有损社区社会资本的观点不同,基层社区党建的延展效应和居民有分寸的自律协调概念,可用以解释中国城市居民住宅小区、尤其是新建商品房住宅小区中社会资本得以生成的现象。居民社区党组织在发挥纵向协调职能时,具有一种作为潜在社会过程的延展效应,导致了居民住宅小区里“有分寸的自律协调机制”的出现,进而生成了居民间的横向社会网络和社区社会资本。对2016年“上海社区研究”（SCS）资料的分析发现,建有活跃党组织的居民住宅小区,会拥有相对较多的居民社团,包括自发型居民社团;在商品房住宅小区里,拥有活跃党组织,同样更有可能形成自发型居民社团。这些发现支持了基于上述论辩的研究假设,表明所提出的中国城市基层党建的延展效应和有分寸的自律协调机制,是能够解释在纵向协调起主导作用的制度环境下社区社会资得以生成的现象的。     

柱切换液相色谱法快速定量检测参附注射液中乌头碱类生物碱和人参皂苷

利用柱切换液相色谱,建立了参附注射液中苯甲酰新乌头原碱、苯甲酰乌头原碱、苯甲酰次乌头原碱、新乌头碱、次乌头碱和乌头碱6种乌头碱类生物碱,以及Rg1、Re、Rf、Rb1、Rc、Ro、Rb2、Rb3、Rd 9种人参皂苷的分析方法。首先利用强阳离子交换的在线固相小柱选择性富集和净化样品中生物碱类成分,优化了色谱条件;并采用EC－C18柱作为人参皂苷的分析柱,通过优化实验条件,结合柱切换方式,去除了样品中辅料等大极性基质成分对色谱柱的污染,实现了生物碱分析和人参皂苷分析的自动切换。结果显示,样品中的生物碱和人参皂苷分离良好,线性相关系数（r2）均大于0.999,连续进样精密度的相对标准偏差（RSD） < 2.0%,重复性的RSD < 2.0%;其中6种生物碱的平均回收率为95.1%～98.6%,检出限为4.0～8.2 ng/mL;9种人参皂苷的平均回收率为91.7%～104%。所构建的基于柱切换液相色谱技术的在线固相萃取方法能够有效去除样品中的基质干扰,快速完成参附注射液中3种单酯型生物碱和9种人参皂苷的快速定量,同时也可对3种双酯型生物碱进行限量检测,可应用于药物的质量评价。     

毛细管气相色谱法分析虾蛄肉中的脂肪酸

以快速脂肪提取器分别提取雄、雌虾蛄肉中脂肪,利用５０ｍ×０．３５ｍｍｉ．ｄ．ＰＥＧ－２０Ｍ玻璃毛细管柱分离测定了雄、雌虾蛄肉中的脂肪酸,结合气相色谱／质谱法,鉴定出４５个峰,分别占脂肪酸总量的９９．２％和９８．０％,其中不饱和脂肪酸分别为７４．７％和７１．５％。     

Characterization of a highly stable zwitterionic hydrophilic interaction chromatography stationary phase based on hybrid organic–inorganic particles

We have characterized a sulfobetaine stationary phase based on 1.7 μm ethylene-bridged hybrid organic–inorganic particles, which is intended for use in hydrophilic interaction chromatography. The efficiency of a column packed with this material was determined as a function of flow rate, demonstrating a minimum reduced plate height of 2.4. The batch-to-batch reproducibility was assessed using the separation of a mixture of acids, bases, and neutrals. We compared the retention and selectivity of the hybrid sulfobetaine stationary phase to that of several benchmark materials. The hybrid sulfobetaine material gave strong retention for polar neutrals and high selectivity for methyl groups, hydroxy groups, and configurational isomers. Large differences in cation and anion retention were observed among the columns. We characterized the acid and base stability of the hybrid sulfobetaine stationary phase, using accelerated tests at pH 1.3 and 11.0, both at 70°C. The results support a recommended pH range of 2–10. We also investigated the performance of columns packed with this material for metal-sensitive analytes, comparing conventional stainless steel column hardware to hardware that incorporates hybrid surface technology to mitigate interactions with metal surfaces. Compared to the conventional columns, the hybrid surface technology columns showed a greatly improved peak shape.