最新刊期
      卷 0 ， 期 0 ， 2020
      • CAO Qingchen~1 ZHANG Yuanxun~1 LOU Yuxia~2 CAO Tong~2 Iida A~3 ZHANG Guilin~1 LI Yan~1 1
        Issue 10, (2008)
        摘要：In order to explore accumulating characteristic of moss as a biological monitor to environmental pollution, cultured Physcomitrella patens of the second generation was grown for 45 days in a specially prepared nutrient medium containing different concentrations of Pb,Fe or Cr,or mixture of Fe-Pb,Fe-Cr and Fe-Cu.Elemental contents in the moss tissue were determined using SRXRF (synchrotron radiation X-ray fluorescence).Cr and K distributions in leaf and stem of the moss were obtained using micro-SRXRF.The results showed that in the sample groups of both types of the medium containing a single heavy metal or the metal mixture,the contents of polluted metal elements in the moss were correlated to the concentrations of corresponding elements in the culture medium. The moss injury was greatly aggravated with increasing content of heavy metal element.Under the contamination of heavy metals,the ability of moss to absorb nutritive elements (K,S) was declined sharply.Also due to the antagonism of excessive Cr,the content of K element deposited in moss stem decreased gradually.  
        关键词：Moss;Heavy metal pollution;Biological monitor;Synchrotron radiation;X-ray fluorescence microprobe   
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        发布时间：2021-03-12
      • CHEN Huanguang LI Rui GUO Chunlong SHEN Tianjian LI Deming
        Issue 10, (2008)
        摘要：Control structure of dynamic power supply using PSI coutroller in SLS and Diamond is introduced.For designing dynamic power supply using PSI controller in the booster of SSRF,an innovative application of PSI digital power supply controller has been developed.In the commissioning of SSRF,the dynamic power supplies performed perfectly.  
          
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        发布时间：2021-03-12
      • LI Zhongliang KANG Le FENG Liangjie ZHAO Feiyun XU Chaoyin
        Issue 10, (2008)
        摘要：In this paper,three geometrical models,i.e.the stiffening ribs,the golden value and slabs slot-cut,were used to minimize the anticlastic distortion caused by cylindrical bent crystal to focus horizontal divergence,and to improve diffraction efficiency of the sagittal focusing monochromator.The parameters were optimized and the results were compared by numerical simulations with finite element analysis (FEA) and measurements of the classical crystal with long-trace-profiler (LTP).Based on beamline parameters of the NSRL-XAFS,the golden value approach is an optimum solution for the second crystal of the monochromator.  
        关键词：Sagittal bent crystal;Minimize the anticlastic distortion;Stiffening ribs;Golden value;Slabs slot-cut   
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        发布时间：2021-03-12
      • HAN Lifeng YUAN Renxian YU Luyang YE Kairong
        Issue 10, (2008)
        摘要：Multi-bunch instabilities degrade beam quality.An FPGA-based digital transverse bunch-by-bunch feedback system was developed at SSRF to suppress beam instabilities.Using the least square fitting algorithm,a Matlab GUI (Graphical User Interface) was programmed and primary experiment results for single bunch are presented in this paper.Further improvement of the feedback system and investigation for multi-bunch are under way.  
        关键词：Transverse feedback;FPGA;Least square fitting method;Matlab GUI   
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        <引用本文> <批量引用> 7227011 false
        发布时间：2021-03-12
      • TIAN Maohui~
        Issue 10, (2008)
        摘要：The hadron therapy system at Institute of Modern Physics will provide carbon ion beams for clinical treatment of in-depth tumors.The beam delivery system,which is used to transfer the beam to irradiation fields,is critical for the heavy ion cancer clinical trials.The tumor is uniformly irradiated.Primarily accelerated by the cyclotron,the heavy ion beam pours into the cooler storage ring main (CSRm) for accumulation and acceleration.The ion beam is extracted by resonance,before the beam is wansferred to the tumor through the transfer line.Based on the medical requirements and technical specifications to design and optimize the transfer line,a set of lens parameters is adopted to flexibly adjust the beam spot size.The feasibility of a scanning system is verified by simulating the beam scanning process.  
        关键词：Deep tumor treatment;Transfer line design;Hadron therapy;Beam distribution   
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        发布时间：2021-03-12
      • LIN Tong~
        Issue 10, (2008)
        摘要：Radioisotope logging technique is an effective method to evaluate groundwater movement.Moving with the water,the isotope tracer distributes differently in different flow states.According to the depth and time distribution of radioactivity,flow state of the groundwater can be determined.In this paper,different flow states,i.e. laminar flow,turbulent flow and mixing flow,are analyzed,and calculation of the flow velocity is discussed.Also,we discuss how to distinguish the laminar flow part and turbulent part in a mixing flow.If one judges the flow state incorrectly,the error of flow velocity will be huge,hence the importance of flow state analysis.Finally,some problems in the practical projects and measuring methods are concluded.  
        关键词：Isotope tracer logging;Laminar flow;Turbulent flow;Groundwater;Flow velocity   
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        发布时间：2021-03-12
      • GONG Yanbao~1 WANG Chengyun~1 LIU Shunying~1 LUO Shufang~1 HUANG Jin~1 YU Jiahui~1 LIU Shiyuan~2 1
        Issue 10, (2008)
        摘要：Core-shell Fe3O4 nanogels with controllable sizes were synthesized under UV irradiation using Fe3O4 nanoparticles as core,N-（2-Aminoethyl）methacrylamide （AEM） as monomer and MBA as cross-linker.The effects of AEM and MBA concentrations and irradiation time on particle sizes of Fe3O4 nanogels were investigated.The particle size,size distribution,morphology,structure and magnetism of the nanogels were characterized by dynamic light scattering,transmission electron microscopy,FTIR,thermogravimmetric analysis,and vibrating sample magnetometer.The results showed that superparamagnetic nanogels with different sizes and narrow size distributions could be synthesized by controlling the irradiation time and concentrations of monomer and cross-linker.Comparing with Fe3O4 nanoparticles,the stability of magnetic nanogels was improved due to their high zeta potential,although their saturation magnetization showed a little tendency to decrease.  
        关键词：Photopolymerization;In situ controllable synthesis;Amino-functionalized;Superparamagnetic;Core-shell nanogels   
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        <引用本文> <批量引用> 7226898 false
        发布时间：2021-03-12
      • LUO Peng YAO Zeen LIANG Yi HU Jifeng JIN Sunjun
        Issue 10, (2008)
        摘要：A model on T(d,n)~4 He(D-T) reaction neutron source,based on the neutron energy spectrum and the angular distribution,was developed.D-T neutron transport in shielding materials was simulated using MCNP code. Three complex shielding schemes for D-T neutron therapy head design were presented by investigating the flux rate, energy spectrum and absorbed dose of neutron andγ-ray outside the shielding system.  
        关键词：T(d,n)~4 He reaction neutron source;Fast neutron;Shielding system;Monte Carlo method   
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        发布时间：2021-03-12
      • ZHAO Huiru~1 GU Yunhong~1 YA Huiyuan~2 JIAO Zhen~1 QIN Guangyong~1 1
        Issue 10, (2008)
        摘要：In this work,we studied the transcription activity of retrotransposon WIS2-1A responding to different doses of N+ implantation at different growth stages of wheat seeds.The time and dose effect of N+ implantation on the transcription of WIS2-1A were analyzed.The results showed that the transcription activity of WIS2-1A decreased with the prolonged growth time in the first 60 h of incubation in the room temperature and vacuum control groups, and the groups implanted with 0.5×1017 N+/cm2 and 1.0×1017N+/cm2.The relative quantification of transcripts in the group implanted with 0.5×1017N+/cm2 and incubated for 30 h was 138 times higher than the control.This indicated that the retrotransposon WIS2-1A probably attributed to the mutation effect of the present generation of wheat.The sensitivity and transcription activity of retrotransposon WIS2-1A responding to N+ implantation could ground the theory of mutation effect induced by low-energy ions implantation.  
        关键词：WIS2-1A;Wheat;Retrotransposon;Low-energy N~+ implantation;Transcription activity   
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        发布时间：2021-03-12
      • SU Dan~
        Issue 10, (2008)
        摘要：A limited opening faraday cup (LOFC) was designed to determine the absorbed dose in different materials of incident proton with energy below 20 MeV.Compared with the traditional FC,the main difference is on the suppressor electrode,which is composed of the outer cup and the tight circle.The distribution of electric field is influenced by the tight circle that could suppress the ejection of secondary electrons effectively,without affecting the ion beam.And this improves the accuracy of FC.  
        关键词：Faraday cup;Secondary electron;Suppress voltage;Absorbed dose   
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        发布时间：2021-03-12
      • CHEN Shaowen~
        Issue 10, (2008)
        摘要：The EGSnrc simulation code DOSRZnrc was used to calculate the absorbed dose conversion factor of Al2O3 dosimeter in MeV photon or electron beams in a water phantom.Simulations were done for a cylindrical geometry dosimeter （diameter 4.0 mm and height 1.0 mm） and the dosimeter was at the centre of the water phantom at different depths.The results reveal that the absorbed dose conversion factor is dependent on both energy of incident beams and depth of the dosimeter in the phantom,and there is an insensitive region where the absorbed dose conversion factor changes slightly.This allows the use of averaged dose conversion factor for the region-specific dosimeter depths and beam energies.  
        关键词：EGSnrc;Monte Carlo simulations;Al2O3;Absorbed dose conversion factor   
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        发布时间：2021-03-12
      • SHI Lingli~
        Issue 10, (2008)
        摘要：With the rapid developments of PET imaging techniques and the research on peptides,during the past decade,numerous studies have been focusing on the 18F labeled peptides,and the labeling methods as well as the applications of these probes have achieved great progress.Synthetic methods of the probes were classified into 11 groups and reviewed in this paper.  
        关键词：Peptides;Fluorine-18;Labeling methods;PET   
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        发布时间：2021-03-12
      • TANG Junlong~1 LI Deming~2 SHEN Tianjian~2 LIU Hong~2 1
        Issue 10, (2008)
        摘要：Based on virtual instrumentation,a reliable and effective test platform,performing instrument control, data acquisition and data recording,has been established to evaluate linearity of high performance DCCT (DC current transducer) for digital power supply at Shanghai Synchrotron Radiation Facility (SSRF).The software in LabVIEW language was developed to perform computer communication via serial communication (RS232) and GPIB, providing a friendly user interface to the linearity test platform.This makes it easy to test the linearity and control power on or off and current output of high-precision and high-current DC constant current output power supply.The experimental data,stored in an EXCEL file,can be processed to obtain DCCT linearity,and provide basis to further analyze DCCT performance in the future.  
        关键词：Virtual instrument;DCCT;Stability;Test   
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        发布时间：2021-03-12
      • XUE Jundong LIANG Hao CHEN Yixin LIU Qiang YU Xiaoqi ZHOU Yongzhao
        Issue 10, (2008)
        摘要：A read out system for muon counter of BESⅢwas developed at USTC.In the system,a data chain connects 16 front-end circuit board (FEC),with an FPGA on each of the FECs.A method using PS mode to configure 16 FPGA chips from 30 m away by LVDS driving and a control chip,was introduced.Another method using MCU to configure the FPGA device in JTAG mode was also presented.SCM has also realized the use of the FPGA configuration chip JTAG programming methods to solve all kinds of the problem-targeted programming.  
        关键词：PS;JTAG,;FPGA;Configure   
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        发布时间：2021-03-12
      • XU Peng HUO Yonggang QIU Xiaolin
        Issue 10, (2008)
        摘要：In this paper,we present aⅥ-based system for measuring nuclear radiations and multi-parameter analysis. It is a platform with Si(Au) and Cd(Zn)Te detectors.The measurement results are evaluated,and performance of the system is discussed.  
        关键词：Virtual instrument;Digital measurement;Ray-type discrimination;Software-coincidence   
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        发布时间：2021-03-12
      • CHANG Yinzhong~1 WANG Xuhui~2 WANG Shilian~1 WANG Jun~1 1
        Issue 10, (2008)
        摘要：The radioactivity concentrations of 7Be,212Pb and 214Pb in the atmosphere of Xi’an suburb were determined from April 2002 to April 2003.A high-volume air sampler and a high resolution gamma-ray spectrometer were used to measure the radioactivity.The annual average concentrations of 7Be,212Pb and 214Pb were 6.68×10-3 Bq·m-3,0.65 Bq/m3 and 16.06 Bq·m-3,respectively.The 7Be levels were higher in spring than those in other seasons, with a maximum concentration of 16.64×10-3 Bq·m-3.They reflected obvious seasonal trends.The concentrations of 212Pb and 214Pb have strong seasonal trends.The maximum concentrations were 1.71 Bq·m-3for 212Pb and 50.11 Bq·m-3 for 214Pb in winter.Precipitation is a major factor affecting the concentrations of 7Be,212Pb and 214Pb,the monthly mean values reach minimum in August,when precipitation is the biggest of all the months.Artificial radionuclides,such as 137Cs,have not been found.  
        关键词：Atmospheric aerosol;Radionuclide concentrations;Xi’an area   
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        发布时间：2021-03-12
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