高效液相色谱法同时测定食品中脂溶性维生素A,D3,E,K3

１引言维生素是维持细胞正常生理功能的营养成分之一。许多维生素是酶的辅基或酶的组成成分，因此，测定食品中维生素的含量是食品营养分析的主要内容之一。脂溶性维生素的分析方法一般采用生物法、分光光度法及薄层色谱法等，但这些方法都只能单独测定食品中的维生素，进入８０年代后，随着高效液相色谱（ＨＰＬＣ）技术在食品分析中的应用，国外许多研究工作者在利用高效液相色谱技术分析脂溶性维生素的研究上作了许多工作，发展了更具选择性的方法如电化学法、质谱法等，并且对同时测定脂溶性维生素的方法作了一些探索。本文旨在综合国内…     

973 RFQ 水冷调谐系统(英文)

由于束流的传输效率对射频四极场加速器(RFQ) 中射频场的分布极其敏感,所以在RFQ 的运行过程中不再采用传统的调谐器调谐RFQ。水冷调谐的方法基本上不影响RFQ 射频场的分布,所以适用于RFQ 的调谐。中国科学院高能物理研究所为C-ADS、CSNS 预研RFQ 项目开发建造了一套水冷调谐系统,使用RF 相位差作为控制量进行RFQ 水冷调谐,相位差的控制精度达到了1°运行结果显示该系统满足了RFQ 的调谐需求。介绍了该系统的水冷系统、调谐控制系统和一些运行经验。Since the beam transmission of a Radio Frequency Quadrupole(RFQ) Accelerator is very sensitive to the field profile, the ordinary frequency tuning method by the local movable tuner is no more adopted in an RFQ operation. The tuning method by controlling cooling water temperature is widely adopted to tune the RFQ due to the less affect on the RFQ field profile. A Resonance Control Cooling System (RCCS) is developed and commissioned for the 973 RFQ,which is a R&D project for C-ADS and CSNS RFQ at IHEP. This system adopts the RF phase difference as control variable to tune the RFQ. The control accuracy of the RF phase difference is about 1°. The running of the 973 RFQ shows that the RCCS works very well and fully satisfies the operation requirement of the RFQ. In this paper, the water skid, resonance control system of the RCCS and the operation experiences will be presented.     

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 ...     

前置导叶对横流风机性能及气动噪声的影响

在横流风机叶轮前加前置导叶(IGV)可以改善横流风机的进口流场,减少叶片上的流动分离,进而降低横流风机的功率。采用非结构化网格RNGκ-ε两方程模型,分别对不加IGV、加IGV1,以及IGV2的横流风机内部流场进行数值模拟,并对三种情况进行气动性能及噪声试验。数值模拟和试验结果表明在加不同IGV以后,横流风机的噪声增大,但是功率在加IGV2后出现了一定的降低。     

Design of the low energy beam transport line for the China spallation neutron source

The design of the China Spallation Neutron Source (CSNS) low-energy beam transport (LEBT) line, which locates between the ion source and the radio-frequency quadrupole (RFQ), has been completed with the TRACE3D code. The design aims at perfect matching, primary chopping, a small emittance growth and sufficient space for beam diagnostics. The line consists of three solenoids, three vacuum chambers, two steering magnets and a pre-chopper. The total length of LEBT is about 1.74m. This LEBT is designed to transfer 20mA of H-pulsed beam from the ion source to the RFQ. An induction cavity is adopted as the pre-chopper. The electrostatic octupole steerer is discussed as a candidate. A four-quadrant aperture for beam scraping and beam position monitoring is designed.     

Design of magnet and control of the beam emittance for Penning H－ ion source

The design requirement and principle of the deflection magnet for Magnetron and Penning H^－ ion source are discussed. It is proved that there exists a maximum emittance for the beam that may be transformed by the magnet into a state with equal Twiss parameters of α_r=α_y and β_r=β_y, which is the requisite condition to get a minimum emittance at the entrance of RFQ after transporting by a LEBT with solenoids. For this maximum emittance, the corresponding magnetic field gradient index is 1.     

350MHz强流质子RFQ加速器工艺腔的研制与测量

为研究强流质子RFQ加速腔的设计与加工工艺,研制了一台全尺寸无氧铜工艺腔.本文介绍了其物理设计与机械设计、机械加工与钎焊工艺研究及其高频性能的测量和调节.经调节,RFQ工艺腔可以达到较为理想的电场分布,其4个象限电场分布的一致性和平整度均能满足要求,二极场分量也足够小     

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.     

分段共振耦合BFQ的调谐与测量

对一长度为3m的分段共振耦合RFQ冷模进行了多次调谐和测量，得到了RF电场平整度好于4％的场分布；解决了分段共振耦合RFQ调谐时捐合单元处RF电场分布出现的台阶问题；确定了分段共振耦合RFQ的调谐步骤。