最新刊期
      卷 0 ， 期 0 ， 2020
      • YAN Wensheng1 LI Chenxi2 WEI Shiqiang1 WU Zhonghua3 NIU Xiaojuan1 CHEN Wei2 LU Kunqua 1
        Issue 3, (2004)
        摘要：The in-situ XAFS technique has been employed to study the local structures of semi-metal Sb in the pre-molten and liquid states. The results reveal that the local structure of the pre-molten Sb at the temperature of 893 K is similar to that of crystalline Sb at 298 K, except that the thermal disorder of the former is relatively larger. With the temperature increasing to 913 K ( melting point Tm= 903 K for the element Sb ) , the main peak intensity of radial distribution function of the molten Sb ( 913 K) is strongly reduced to about 70% of the pre-molten Sb ( 893 K ) . This indicates that the structural disorder of the liquid Sb increases remarkably during the solid-liquid tran- sition, which can be attributed to the fact that the covalent bonds of the first shell are mostly broken in liquid Sb. The results obtained from the model-independent reverse Monte Carlo calculation in the process of solid-liquid transition shows that the coordination number of the first neighbor around Sb atoms increases from 6 to 9. As the temperature further rises to 1058 K, the radial structural function of Sb ( 1058 K ) indicates that liquid Sb possesses a similar local structure in the temperature range of 100—200 K beyond the melting point.  
        关键词：In-situ XAFS;Liquid Sb;Solid-liquid transition;Local structure   
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        发布时间：2021-03-12
      • GAO Yuxi1 FENG Weiyue1 LI Bai1 ZHANG Peiqun1 HE Wei2 HUANG Yuying2 CHAI Zhifang1 1
        Issue 3, (2004)
        摘要：A procedure based on isoelectric focusing ( IEF ) separation and synchrotron radiation X-ray fluorescence ( SRXRF ) analysis for speciation of trace elements in biological samples was preliminarily established. The proteins in human liver cytosol were separated by IEF, and zinc amount in each protein band was measured by SRXRF. The results indicate that there were three main zinc-containing bands with isoelectric points ( pIs) of 4.69, 5.93, and 9.84 present in the sample, and the zinc percentages in the three bands to the total recovered zinc were 33.08%, 17.05%, and 26.54%, respectively. In addition, several zinc-containing proteins were present in the pI range of 6.6 ? 9.3, which amounted to 23.33 % of the recovered zinc.  
        关键词：Speciation;Zinc-containing protein;Synchrotron radiation X-ray fluorescence;Isoelectric focusing;Human liver cytosol   
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        发布时间：2021-03-12
      • LIU Yi1 LIU Lin2 WANG Jun3 DONG Baozhong3 1
        Issue 3, (2004)
        摘要：The crystallization of Zr55Cu30Al10Ni5 bulk amorphous alloy near the glass transition temperature has been investigated by synchrotron radiation X-ray small angle scattering （SAXS）. The experimental results show that of crystal particles in amorphous matrix are formed during the annealing of 400°C — 442°C which is near glass transition temperature. It is found that there are no obvious differences in the size of precipitated crystal particles and that the number of precipitated particles increases with the increase of annealing time at the given annealing temperature, or increases with the increase of annealing temperature in the given annealing time.  
        关键词：Synchrotron radiation;Small angle X-ray scattering;Bulk amorphous alloy;Glass transition;Isothermal annealing   
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        发布时间：2021-03-12
      • WEN Li1,2 HE Jianhua1 XIA Shaojian1 HOU Zhengchi1 ZHOU Renkui2 LUO Changzhou2 1
        Issue 3, (2004)
        摘要：Firstly the role and structure of the sagittally focusing double-crystal monochromator are introduced briefly. Dimensions of the diffraction crystal are determined according to the design requirement. Different kinds of distortions of the diffraction crystal subject to high heat load from synchrotron radiation beam are analyzed. Direct water-cooling is adopted to release the high heat load. The grooved crystal and the cooling structure are designed. Then material choice, orientating and cutting, and grooving of the diffraction crystal are completed in succession. At last the directly water-cooled diffraction crystal applicable for the sagittally focusing double-crystal monochromator is produced which can bear heat load stand of more than 0.5W/mm2.  
        关键词：Double-crystal monochromator;Diffraction crystal;Directly water-cooled crystal;High heat load   
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        发布时间：2021-03-12
      • ZOU Lixin1 ZHU Guirong1 XIA Shaojian2 TANG Rongsheng1 ZHANG Yaoming1 FU Yuan2 1
        Issue 3, (2004)
        摘要：A control system used to adjust precisely the slit for 3B3 beam line of Beijing Synchrotron Radiation Facility, is introduced. The electronic interpolation technique of step-motor and the method for improving reliability of the system are adopted. In addition, advantage, reliability and intelligentization of the system are analyzed.  
        关键词：Beam line;Slit control system;Electronic interpolation   
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        发布时间：2021-03-12
      • CHEN Zhongjun WU Zhonghua XIAO Xianghui HONG Xinguo DING Yongfan DONG Baozhong
        Issue 3, (2004)
        摘要：In this paper, the impovement and on-line adjustment of the monochromator of beamline 4B9A at BSRF were reported. The fixed beam exit of the monochromator and monochromatized X-ray intensity were tested. The results demonstrated that the indirect water-cooling monochromator is stable and mechanical instabilities are almost eliminated. It satisfies the experimental requirements of X-ray diffraction and Small Angle X-ray Scattering Stations at beamline 4B9A.  
        关键词：Monochromator;Beamline;Synchrotron radiation   
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        发布时间：2021-03-12
      • YUE Weisheng LI Xiaolin LI Yan WANG Yongqi ZHANG Guilin
        Issue 3, (2004)
        摘要：A new method for sample preparation of individual aerosol particle in SPM analysis was developed. Aerosol particles were collected directly on the polyvinyl butyral ( PVB ) foil by using air sampler. Microscopic observation indicates that the particles were separated completely and the interval of particles was reasonable. The SPM experiment proves that PVB foils have excellent stability under proton microbeam bombardment and are a suitable backing material for supporting the single particle for SPM analysis.  
        关键词：Scanning proton microprobe;Single aerosol particle;Atmospheric aerosol   
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        发布时间：2021-03-12
      • YANG Hailiang QIU Aici SUN Jianfeng HE Xiaoping ZHANG Jiasheng TANG Junping WANG Haiyang XU Ri PENG Jianchang REN Shuqing LI Peng ZHANG Guoguang YANG Li HUANG Jianjun OUYANG Xiaoping
        Issue 3, (2004)
        摘要：The 6—7 MeV quasi-monoenergetic pulsed γ -rays were produced on the FLASH Ⅱ accelerator. The pulsed γ -rays were generated via intense pulsed high power proton beam striking F target and measured with the 19 PIN semiconductor detectors and ST401 plastic scintillators. The yield of the quasi-monoenergetic pulsed γ photons from the 19F ( p, αγ ) 16 Ο reaction was calculated. By placing the target far enough downstream so that the time-of-flight was greater than the duration of the diode bremsstrahlung pulse, the quasi-monoenergetic pulsed γ -rays were discriminated from the diode bremsstrahlung, and the bremsstrahlung was depressed due to extending the distance between detector and diode. The quasi-monoenergetic pulsed γ -rays and their time delay were measured with ST401 plastic scintillator photomultiplier and the PIN semiconductor detector at various transmission distances. The proton energy at the beam current peak time was calculated by time-of-flight method. It is demonstrated by a series of experiments that the Cu, Cr, stainless steel target and the impurity in the target would not produce γ -ray interferences with other energies.  
        关键词：Quasi-monoenergetic pulsed γ -rays;Intense pulsed proton beam;PIN semiconductor detector;Photomultiplier;Time-of-flight;Bremsstrahlung   
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        发布时间：2021-03-12
      • ZHENG Qiwen TANG Jingyu ZHANG Shenghu
        Issue 3, (2004)
        摘要：A bridged-T type all-pass network is introduced in this paper with its calculation results and frequency responses. With the utilization of this all-pass network, a new type of tuning-free RF acceleration cavity is obtained for synchrotron. The merits of better performance of such a tuning-free RF cavity than the conventional tuning RF cavity make it very attractive in synchrotron application. The possibility of using such a tuning-free RF cavity in HIRFL-CSR (Cooler Storage Ring) project at Lanzhou is also discussed. By applying multiple-frequency flat-topping acceleration technique, the capture efficiency of the radioactive ion beam of large emittance at CSR will be enhanced.  
        关键词：Bridged-T all-pass network;Synchrotron;RF acceleration cavity   
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        发布时间：2021-03-12
      • WAN Junsheng1 ZHANG Ying1 ZHANG Lixing1 YU Hongwei2 XIA Haihong2 DING Dazhao2 1
        Issue 3, (2004)
        摘要：The standard spallation target of ADS (Accelerator-Driven System) was theoretically calculated with Monte Carlo codes of DCM/CEM and LAHET in the present work. The spallation target (0.6 m long and 0.2 m in diameter) bombarded with 0.15—1.6 GeV energetic proton beam was simulated. The proton energy deposition in tar- get, neutron yield, neutron fluence distribution on the outer surface of target and the neutron spectrum distribution were simulated with the two codes. It is shown that, in the proton energy range of 0.8—1.0 GeV, both calculated re- sults agree to each other; but when the proton energy falls outside this energy range, there are some differences be- tween the results with both codes.  
        关键词：ADS;Spallation target;Neutron yield;Energy deposition;Neutron distribution   
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        发布时间：2021-03-12
      • ZHANG Xun1 CHEN Jiangfeng1 MA Lin1 HE Jianfeng1 WANG Changsui2 QIU Ping2 1
        Issue 3, (2004)
        摘要：The discriminating of production sites of ancient pottery samples using multi-isotopic systematics was described. Previous work has proven that Pb isotopic ratios can be used for discriminating the production sites of ancient pottery under certain conditions. The present work suggests that although Nd isotopic ratios are not sensitive to the production sites of ancient pottery, Sr isotopic ratios are important for the purpose. Pb isotopic ratios are indis- tinguishable for the pottery excavated from the Jiahu relict, Wuyang, Henan Province and for famous Qin Terra-cotta Figures. But, the 87Sr/86Sr ratios for the former (about 0.715) are significantly lower than that of the latter (0.717—0.718). We concluded that a combined use of Pb and Sr isotopes would be a more powerful method for dis- criminating the production site of ancient pottery.  
          
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        发布时间：2021-03-12
      • PANG Jufeng TIAN Yajuan WU Jie
        Issue 3, (2004)
        摘要：Under the conditions of an open hole well, without instruments in borehole, fresh water -saturated sandstone formation with various porosities, and with injected fresh water in borehole, the software package of Monte Carlo method for simulating neutron-γ logging was used to calculate the neutron-γ-ray distributions with energy and time and neutron-γ-ray spectra for the certain points of borehole axis and wall.  
        关键词：Monte Carlo simulation;Neutron-γ logging;Porosity;γ-ray spectra;Water sandstone formation   
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        发布时间：2021-03-12
      • SUN Youmei ZHU Zhiyong JIN Yunfan WANG Zhiguang HOU Mingdong
        Issue 3, (2004)
        摘要：Stacked polyimide (PI) films of about 25 μm in thickness were irradiated with 1.755 GeV xenon ions under vacuum at room temperature. The chemical changes of modified PI films were studied by Fourier transform infrared (FTIR) and ultraviolet/visible (UV/Vis) absorption spectroscopy. The FTIR results show that the absorbance of the typical function groups decreases exponentially as a function of fluence. Under 8.8 keV/nm (minimum) and 11.5 keV/nm (maximum) electronic energy loss of 136Xe irradiation, the mean degradation radius of all function groups in PI is 3.6 and 4.1 nm, respectively. The alkyne end group was found after irradiation and its formation radius was 5.6 nm and 5.9 nm corresponding to 8.8 keV/nm and 11.5 keV/nm, respectively. The UV/Vis analysis indicates the radiation induced absorbance change follows a linear relation with fluence, and the production efficiency of chromospheres depends strongly on the electronic energy loss ( d E / d X ) e.  
        关键词：Swift heavy ion irradiation;Electronic energy loss;Polyimide;Chemical degradation   
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        发布时间：2021-03-12
      • SONG Zhaohui1 ZHANG Dingkang1 WANG Kuilu1 HU Huasi2 1
        Issue 3, (2004)
        摘要：This paper analyzes the statistical fluctuation of scintillation detectors in the field of low intensity gamma pulse rays. It is found that the statistical fluctuation of scintillation detectors is affected not only by intensity of incident gamma pulse rays, timing distribution, spatial distribution and energy distribution, but also by interaction between gamma rays and detectors, energy deposition, emission and transportation of fluorescence photons, interactions between fluorescence photons and photocathode, and between photoelectrons and dynodes. The formula on statistical fluctuation of scintillation detectors is deduced. The statistical errors of three types scintillation detectors composed of different scintillators and photomultiplier tube 9815B under the lowest measurement limit of gamma pulse rays are estimated.  
        关键词：Scintillation detectors;Lowest measurement limit;Collection efficiency;Statistical fluctuation   
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        发布时间：2021-03-12
      • YANG Dailun1 GOU Chengjun1 TANG Zhiquan2 LUO Zhengming1 1
        Issue 3, (2004)
        摘要：The dose algorithm by matrix model has been modified. The jobs involved include the establishment of the matrix of field with the convenience and nicety to deal with every fields, and a formula on interpolation of cen- troid was brought forward to increase the precision of computation. Because of its higher calculating speed, the algo- rithm is suitable to the speediness of the treatment planning systems.  
        关键词：Treatment planning system;Dose calculation algorithm;Matrix model   
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        发布时间：2021-03-12
      • A Jingye CHEN Da ZHANG Wenshou CHEN Weishi
        Issue 3, (2004)
        摘要：An automatic nuclide identification system has been established on the microcomputer in Xi’an Pulse Reactor. It has advantages of easily and quickly using, high efficiency and so on. It is based on the input data of conventional spectrum processing including peak energies, peak areas and their uncertainties. By using this software, we have completed a lot of nuclide identification work in NAA. The results are satisfying.  
        关键词：Neutron activation analysis;Nuclide identification   
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        发布时间：2021-03-12
      • WANG Quanjin YE Yanlin JIANG Dongxing LI Zhihuan HU Qingyuan CHEN Zhiqiang HUA Hui CHEN Tao LI Xiangqing GE Yucheng
        Issue 3, (2004)
        摘要：For measuring the energy of neutrons by the TOF ( Time of Flight ) method, a new method named “measuring the absolute time difference” was presented to measure the relative time difference of all the electronics. The time resolution of this method has been studied in detail. A good condition for time resolution was concluded. The best time resolution could be less than 60 ps.  
        关键词：Neutron energy;TOF;Time resolution   
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        发布时间：2021-03-12
      • ZHOU Gang ZHANG Dafa CAI Zhangsheng
        Issue 3, (2004)
        摘要：The application of artificial neural networks (ANN) in the field of nuclear power was reviewed. This pa- per analyzed especially the progress of using ANN in nuclear power control systems, monitoring and transient identi- fication, fault diagnosis, fuel management, nuclear parameter prediction or approximation and so on in nuclear power plants. Some authors’ views were put forward.  
        关键词：Artificial neural networks(ANN);Nuclear power;Control;Monitoring;Fault diagnosis;Prediction;Management;Wavelet neural network   
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        发布时间：2021-03-12
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