最新刊期
      卷 0 ， 期 0 ， 2020
      • DONG Shuqiang1,2 LI Ming3,2 SHI Hong2 FU Zhaoping1,2 LIU Peng2 1
        Issue 7, (2008)
        摘要：In this paper we present the structure and primary results of a stability monitor system, which is newly constructed for a macromolecule crystallography station (1W2B) of Beijing Synchrotron Radiation Facility (BSRF). The system consists of optimized double-blades beam position monitor (BPM), double-wires BPM, fluorescence target, ion chamber, and fluorescence detector etc. It monitors the incident beam at front end and sample position and finds the source of beam instability immediately. Otherwise, by virtue of the system, the position of the electron orbit in insertion device can also be monitored in real time that gives an important advice of building slow feedback system of BSRF.  
        关键词：Double-blades BPM;Double-wires BPM;Stability monitor system;Beijing Synchrotron Radiation Facility (BSRF)   
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        发布时间：2021-03-12
      • LI Yongjun1,2 LU Qipeng1 PENG Zhongqi1 CHEN Jiahua3 1
        Issue 7, (2008)
        摘要：Six-bar parallel mechanism is widely used in synchrotron radiation facilities for X-ray optics of the beam-lines.The six-dimensional adjustment, however, is difficult and inefficient without theoretical direction. Toachieve improved speed and accuracy of the six-dimensional adjustment, characteristics of the parallel mechanism are analyzed. By means of coordinate transformations, the inverse kinematics of six-bar parallel mechanism is studied, and the precise equations for six bars length are obtained. Curves of six bars length are represented after simulating and calculating by MATLAB. The result shows that the method is fast and efficient, the linear resolution can be better than 5 μm and the rotational resolution can be better than 3". This method satisfies practical requirement and provides a theoretical foundation for the platform’s fine adjustment in synchrotron radiation beam-line.  
        关键词：Synchrotron radiation;Beam-line;Six-bar parallel mechanism;Inverse kinematics;Monochromator   
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        发布时间：2021-03-12
      • HAN Lifeng YUAN Renxian YE Kairong
        Issue 7, (2008)
        摘要：Least Square Fitting was used to design a FIR filter of the transverse feedback system for the Shanghai Synchrotron Radiation Facility (SSRF). The algorithm helped us to set appropriate gain and phase at special frequency points. This reduced the power needed for damping the beam oscillations, which was proved by System View signal simulation. And with AT (Accelerator Tool) simulation, the Gain calculation and settings to the output signals from the FIR filter were deduced. The relationship between the Kicker power and the system damping time was also given.  
        关键词：Transverse feedback;Least square fitting method;AT simulation   
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        发布时间：2021-03-12
      • LI Yuan LI Haohu LIU Guimin LI Deming
        Issue 7, (2008)
        摘要：The layout of injection and extraction system were introduced in this paper. The horizontal and vertical injection acceptance are about 23 πmm·mrad and 37 πmm·mrad, respectively, while emittance of the injected beam is 9 πmm·mrad (3σ). This ensures the high injection efficiency. Three slow kickers can form a good bump. The inside position of the entrance of septum is set to 15 mm, where the bumped beam and the extraction beam are 10 mm and 22 mm, respectively, far from the booster central orbit.  
        关键词：SSRF;Booster;Injection and extraction system   
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        发布时间：2021-03-12
      • LIU Yingxin1 QIN Shan1 LI Haijian2 LI Xiaodong3 LIU Jing3 1
        Issue 7, (2008)
        摘要：In situ high-pressure energy dispersive X-ray diffraction experiments on natural topaz have been carried out using diamond anvil cell (DAC) device on Beijing Synchrotron Radiation Facility. The pressure dependence of the lattice parameters of topaz is reported up to 29.7 GPa at room temperature. In the experimental pressure range, no evidence was observed for the phase transition of topaz. The Murnaghan equation of state was used to fit the P-V data, assuming the pressure derivative K′ =4, and the isothermal bulk modulus K298 =199.7 (4.6) GPa was obtained.  
        关键词：Topaz;Synchrotron radiation;High-pressure;Structure;Phase transition   
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        发布时间：2021-03-12
      • LIU Ke1 TONG Shuilong2 LI Ruipeng1 TENG Maikun2 NIU Liwen2 XU Chaoyin1 SHENG Liusi1 PAN Guoqiang1 1
        Issue 7, (2008)
        摘要：In this paper, the main equipment for the macromolecule crystallography in X-ray diffraction and scattering station of NSRL is introduced. It uses the sulfur single wavelength anomalous diffraction (S-SAD) to solve the three dimensional structure of protein crystal. Test results indicate that the X-ray diffraction and scattering station can satisfy the request of single-wavelength anomalous scattering experiments.  
        关键词：Application of synchrotron radiation;X-ray diffraction;Protein;Crystallography;S-SAD   
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        发布时间：2021-03-12
      • CHOU Wenjun ZHOU Dayong CHEN Jianfeng SHEN Liren LIU Yajuan
        Issue 7, (2008)
        摘要：This paper describes a machine interlock and protection system used for accelerators based on EPICS (Experimental physics and industrial control system). The system is composed of a front-end computer and an FM-3R logic controller PLC. The alarm signal is passed by the hardware directly, and would be deal with PLC. The reporting, recording and analyst of the event are accomplished by EPICS control software. And PLC is linked to the EPICS by Internet.  
        关键词：Control system;EPICS;PLC;Machine interlock   
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        发布时间：2021-03-12
      • CHEN Mincong LI Hongmei CHEN Ziyu SHEN Ji
        Issue 7, (2008)
        摘要：X-ray equivalent energy can be used to measure mass thicknesses of materials. Based on this, a method of mass thickness measurement of dual-sample was discussed. It was found that in the range of sample mass thickness under investigation, the equivalent mass attenuation coefficient of a component could be used to compute mass thicknesses of a dual-sample, with relative errors of less than 5%. Mass thickness measurement of a fish sample was performed, and the fish bone and flesh could be displayed separately and clearly by their own mass thicknesses. This indicates that the method is effective in mass thickness measurement of dual-sample of suitable thicknesses.  
        关键词：Dual-energy;X-rays;Equivalent energy;Attenuation coefficients;Mass thickness   
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        发布时间：2021-03-12
      • DING Dong YING Mingli ZHOU Changwei GUO Liping FU Dejun
        Issue 7, (2008)
        摘要：GaN films were grown by intermediate-frequency magnetron sputtering of pure Ga metal target on Si(111) substrate. The properties and the contents of GaN films were analyzed by X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS), respectively. The relationships between the total gas pressure, the substrate position and temperature, and crystallization quality and element contents of the GaN films, were investigated. The results showed that preferred orientation of GaN (002) was achieved at total gas pressures of 0.4～1.0 Pa. Little diffraction of GaN (002) could be observed either at pressures below 0.4 Pa or above 1.0 Pa. The Ga:N ratio was 1:1 for films prepared under the optimized conditions.  
        关键词：Middle-frequency magnetron sputtering;GaN;X-ray diffraction;Deposition rate   
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        发布时间：2021-03-12
      • GUAN Qingfeng CHENG Duqing CHEN Kangmin PAN Li
        Issue 7, (2008)
        摘要：AISI 304 austenitic stainless steel specimens were irradiated with high current pulsed electron beam (HCPEB) for 1, 5 or 10 pulses. The defect cluster microstructures were investigated by transmission electron microscopy (TEM). While the 1-pulse HCPEB irradiated specimen dose not show any microstructure change, the original microstructure changed completely after the repeated HCPEB irradiation. Dense small defect clusters in sizes of a few nanometers were introduced in the sample, and part of them can be resolve as stacking fault tetrahedral (SFT). For 10-pulse HCPEB irradiation, large-size SFTs normally located at the tip of twin lamellae, and sometimes located in or inside twin lamellae were formed. The largest SFTs were 250 nm approximately. The formation mechanism of large-size SFTs is different from that of the small counterpart. There is a close relationship between large-size SFTs and twin lamellae.  
        关键词：High current pulsed electron beam;Austenitic stainless steel;Vacancy cluster defects;Stacking faultt etrahedral   
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        发布时间：2021-03-12
      • SHI Shaomeng CHEN rongchang XUE Yanling REN Yuqi XIAO Tiqiao
        Issue 7, (2008)
        摘要：Inertial fusion chamber is conducted in a metal chamber with polymer capsules. And the capsules are usually made of carbon, hydrogen and other low Z materials. It is difficult for traditional X-ray imaging technique to detect the inertial fusion capsules. X-ray phase contrast imaging has been used in low Z material imaging. However it has not been applied to low Z materials wrapped by strong absorption materials. In this paper, we construct a model and discuss the effect of parameters such as X-ray energy, distance of object to detector, and thickness of strong absorbing materials, on phase contrast imaging quality by simulation and experiment. We found it feasible to perform high resolution and nondestructive detection of inertial fusion capsules in a chamber by X-ray phase contrast imaging. And this technique may have other applications, such as inclusion detection in petroleum exploration.  
        关键词：Inertial fusion capsule;Nondestructive detection;X-ray phase contrast imaging   
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        发布时间：2021-03-12
      • ZHANG Conghua1,2 YANG Yong2 ZHANG Yuanyue2 SU Hongyu2 ZHENG Yongming2 GONG Lan2 ZHANG Youde2 ZOU Xuchun2 1
        Issue 7, (2008)
        摘要：An automatic phantom scanning system was developed at our laboratory. Its performance, i.e. the percentage depth-dose curves and off-axis ratio curves, was tested on an Elekta Precise linac with 6 and 18 MeV electrons, and their X-rays. The results were compared with the Blue Phantom system, the most advanced water phantom system in the world. The curves obtained from the two automatic water phantom systems agree perfectly. The error of the percentage-dose in the corresponding depth for photon beams is less than 1%. The error of the percentage-dose in the corresponding depth below maximum dose point for electron beams is less than 1%, too. Off-axis ratios of fields for photon and electron beams are consistent. This indicates that its performance is as good as the advanced phantom.  
        关键词：Beam analysis technology;Water phantom;Percentage depth-dose;Off-axis ratio of field   
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        发布时间：2021-03-12
      • YANG Yuzhang1 ZHANG Juzhong2 1
        Issue 7, (2008)
        摘要：The minor and trace elements in the bluish-white porcelain bodies of Fanchang kiln in different dynasties were determined by instrumental neutron activation analysis (INAA). Multivariable statistical analysis of the experimental data was carried out by SPSS software. The results show that the contents of Yb, Ta, Hf and Th varied notably between early and middle North Song Dynasty. The chemical compositions of Fanchang porcelain bodies can be divided into three groups corresponding to Five Dynasties, early Northern Song and middle Northern Song. Combined with the results of major elements analysis, we think that the raw materials of Fanchang kiln varied in different periods and the using up of fine raw materials was the main reason of Fanchang kiln’s decline.  
          
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        发布时间：2021-03-12
      • HU Sheng GU Mei XIAO Chengjian LUO Yangming WANG Heyi LUO Shunzhong ZHU Zuliang REN Xingbi
        Issue 7, (2008)
        摘要：Pt/C catalysts were prepared by conventional and improved impregnation-reduction method, or microwave heating method. Transmission electron microscopy analyses indicated that average sizes of Pt particles by the three methods were (2.9±0.8) nm, (2.0±0.7) nm and (1.9±0.5) nm, respectively. X-ray photoelectron spectroscopy measurements revealed that the Pt(0) contents of the Pt/C catalysts by microwave heating method and improved impregnation-reduction method are 40.9% and 43.3%, respectively. The Pt/C catalysts obtained by microwave heating method were reduced by H2/N2 mixed gas in 300℃ for 2 h, or 500℃ for 1 h. The average sizes of Pt particles increase to 2.2 and 2.1 nm, and the Pt(0) contents increase to 44.3% and 49.7%, respectively. The polytetrafluoroethylene and Pt/C catalysts were supported on foamed nickel (FN) to obtain hydrophobic Pt/C/FN catalysts, and the catalytic activities of the hydrophobic catalysts were investigated for hydrogen-water liquid phase exchange reaction. The average size of Pt particles and the Pt(0) content have influences on the catalytic activity of the Pt/C/FN catalyst. The increased dispersion of Pt particles or Pt(0) contents increases catalytic activities of the hydrophobic catalysts.  
        关键词：Hydrophobic catalysts;Hydrogen-water liquid phase catalytic exchange reaction;Hydrogen isotope separation;Pt/C catalysts   
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        发布时间：2021-03-12
      • MEI Ying
        Issue 7, (2008)
        摘要：Sodium fluorescence method is an important method for on-site test of nuclear HEPA filters. In this paper, the test principle of sodium fluorescence method, test data recording, test data processing and a sodium fluorescence aerosol generator developed in co-operation with Institute of Radiation Protection of China is introduced. Practice in the past a few years proved that the sodium fluorescence aerosol generator is reliable and effective, and is ready for wide applications.  
        关键词：HEPA filter;Site test;Sodium fluorescence method;Decontamination factor   
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        发布时间：2021-03-12
      • PENG Shuaijun WU Zhifang
        Issue 7, (2008)
        摘要：Fast online inspection in steel pipe production is a big challenge. Radiographic CT imaging technology, a high performance non-destructive testing method, is quite appropriate for inspection and quality control of steel pipes. The method of rotating polar-coordinate is used to reconstruct the steel pipe section from few projections with the purpose of inspecting it online. It reduces the projection number needed and the data collection time, and accelerates the reconstruction algorithm and saves the inspection time evidently. The results of simulation experiment and actual experiment indicate that the image quality and reconstruction time of rotating polar-coordinate method meet the requirements of inspecting the steel tube section online basically. The study is of some theoretical significance and the method is expected to be widely used in practice.  
        关键词：Steel tube inspection;CT imaging;Few projections;Rotating polar-coordinate   
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        发布时间：2021-03-12
      • WANG Peng1,2 Lü Junhong1 WANG Xinyan1,2 YANG Haijun1,2 WANG Huabin1,2 HUANG Yibo1 LI Bin1 1
        Issue 7, (2008)
        摘要：Atomic force microscope (AFM) is a powerful tool for virus studies. The recombinant adeno-associated virus serotype 2 (rAAV2) has an intendancy to aggregate in liquid or on solid surface. Moreover, changes in virus shape induced by compressing force of the AFM tip hamper studies on virus topography. In this paper, chemical re-agent of glutaraldehyde (2%, v/v) pre-mixed with virus suspension facilitates the dispersion of rAAV2 particles de-posited on both the mica and HOPG surface. In addition, the height of virus particle is up to near 20 nm with the in-crease of concentration of glutaraldehyde.  
        关键词：Atomic force microscope (AFM);rAAV2;Glutaraldehyde;Surface;Dispersion   
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        发布时间：2021-03-12
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