最新刊期
      卷 0 ， 期 0 ， 2020
      • LIU Shuhui WANG Lin FENG Guangyao ZHANG Shancai LI Weimin
        Vol. 34, Issue 3, (2011)
        摘要：In this paper,a new injection scheme using a single pulsed quadrupole magnet(PQM) is introduced.Through the physics and numerical simulation of injection process,the location and strength of the PQM for the storing ring of Hefei Light Source(HLS) are determined.Evaluated from the simulation results,the rate of the survival beam and the disturbance of the stored beam are given.The feasibility of putting the new injection scheme using a PQM into HLS with the purpose of beam injection is proved.  
        关键词：Electron storage ring;Injection beam;Stored beam;Pulsed quadrupole magnet;Injection efficiency;Stored beam disturbance   
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        发布时间：2021-03-05
      • WANG Naxiu1 LIU Shilei1,2 XU Zhongmin1 ZHANG Min1 WU Guanyuan1 1
        Vol. 34, Issue 3, (2011)
        摘要：In this paper,we report our work to handle with the heat load of photon shutter in front ends of the Phase I beamlines at Shanghai Synchrotron Radiation Facility(SSRF).The heat load had been simulated with the ANSYS FEA software in designing the beamlines.Efforts were made recently to measure temperature of the photon shutters.The FEA and experimental results were compared.The simulated results agree with the measurement data within an error range of 10°C,with the FEA value being always larger than the measured ones.This indicates that the water-cooling design method of photon shutter is correct and the simulation of high heat load components cooled directly by water can ensure safety of the device.  
        关键词：Cooling of high heat load;Photon shutter;FEA simulation   
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        发布时间：2021-03-05
      • LIU An WANG Xufei LI Jiaqing ZHANG Jiexiong WANG JianzhongHE Zhijiang ZHANG Wei ZHANG Bin SHI Liqun
        Vol. 34, Issue 3, (2011)
        摘要：A first-order simulation is performed on beam optics of the Fudan single-ion microbeam facility,which is designed to irradiate individual living cells at highly localized spatial region with accurately controlled dose.A typical proton beam of 1.5 MeV for routine experiments is simulated.The results of the transporting beam envelope and the beam profile,the phase space and the divergence angles at the end of the beam line show good status(x<0.2 cm,y<0.3 cm;x’<4.8 mrad,y’<6.5 mrad) for extracting a collimated microbeam.Concerning the possible influences of space charge effects,1.5 MeV protons with a beam current up to 7 mA(far higher than common value) is also calculated,the beam size at the end of the beam line can still be focused within 0.6 cm in diameter,with the divergence angles below 6.5 mrad.The results are still good enough for the requirements of a collimated microbeam through the capillary collimator.  
        关键词：Microbeam;Single-ion;Beam optics;TRANSPORT;TURTLE   
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        发布时间：2021-03-05
      • YANG Anming1 XIA Liansheng1 WANG Hui2 YU Zhiqiang2 LI Ji2 SHI Jinshui1 ZHANG Huang1 LIU Xingguang1 LIU Yunlong1 PAN Haifeng1 1
        Vol. 34, Issue 3, (2011)
        摘要：For kA thermal emission current of electron beams,we developed a Φ100 mm scandate cathode,and established a 2 MV injector test stand with the large area thermionic cathode.Experiment results showed that under the diode voltage of 1.95 MV,pulse width at 120 ns(FWHM),cathode temperature at 1120°C,the maximum emission current was 1038 A,with an emission current density of about 13 A/cm2.The results also indicates that under these conditions,the cathode is still working in the space-charge limited current state.  
        关键词：LINAC;Thermionic dispenser cathode;Diode;Current density   
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        发布时间：2021-03-05
      • MA Minyang1 QIN Xiubo2 JIANG Xiaopan2 YU Runsheng2 WANG Baoyi2 WU Weiming1 1
        Vol. 34, Issue 3, (2011)
        摘要：Positron annihilation lifetime spectroscopy(PALS) is a useful technique for nano-defects identification in materials.The positron annihilation status and electrondensity distribution in materials can be obtained by PALS.In this paper,based on characteristics of the genetic algorithm(GA) global search and generation of the initial value randomly,a multi-exponential function fitting of theoretic PALS is attempted,and the curve fitting is performed by using MATLAB.The life expectancy of each component and the corresponding intensity is achieved.The results deduced from the GA and the LifeTime9.0 are compared.The parameters PALS are analyzed by the GA,which does not request assigning experiential initial value and does not involve local optimum.  
          
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        发布时间：2021-03-05
      • CHEN Zhenping1 ZHANG Guofang2 XUE Renzhong1 SHI Kai1 LI Tao1 WANG Chunmei1 XUE Yuncai1 1
        Vol. 34, Issue 3, (2011)
        摘要：The crystal structure,local electron density and superconductivity were investigated by X-ray diffraction,positron annihilation and other methods for Fe-doped GdBa2Cu3-xFexO7-δ(x=0.00-0.30) systems.The results showed that the crystal structure of the samples evolved a phase transition from orthorhombic to tetragonal near x=0.10.The superconducting transition temperature Tc decreased with increasing Fe doping amounts,and the superconducting transition width changed strikingly for O-T phase transition samples.The width increased markedly for the tetragonal phase ones.The results from the positron experiments indicated that the local electron density displayed a noticeable change when the O-T phase transition took place in the systems.It was found that the superconducting transition temperature Tc decreased with the local electron density.These findings manifest that the crystal phase transition and the local electron density can strongly affect the superconductivity in the Fe doped GdBa2Cu3-xFexO7-δ systems.  
        关键词：Positron annihilation;Structure phase transition;Superconductivity;Local electron density   
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        发布时间：2021-03-05
      • ZENG Xinmiao ZHOU Peng QIN Peizhong BAO Mao GUO Guangshui XU Ziyan
        Vol. 34, Issue 3, (2011)
        摘要：In this paper,the MCNP code is used to calculate neutron transmission through various materials of 1–40 cm thickness in energy range of 0.025 eV to 20 MeV.The materials are principal shielding materials of PE,water,concrete,Fe,Cu,Pb and PE/BC4composite,and the additives of B4C and Gd2O3.The following results were obtained:(1) the neutron transmission decreased with increasing thicknesses of a material;(2) for a certain material,with decreasing energy of the neutrons,the neutron transmission decreased faster,except PE and water,where the neutron transmision keeps almost the same in the entire energy range;and(3) for low energy neutrons,the differences of transmission decreasing trend with the increasing thicknesses for different materials were significant,whereas for high energy neutron,the decreasing trend was not distinct.A combination of a main material with an additives can achieve better shielding effect.  
        关键词：Neutron;Transmission coefficient;Monte Carlo program;Shielding material;Functional additive   
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        发布时间：2021-03-05
      • YAN Zheng WU Xinmin DENG Lei ZHANG Ye ZHENG Yongming YANG Yaxin
        Vol. 34, Issue 3, (2011)
        摘要：In this paper,a Monte-Carlo model is used to analyze the diffusion of radioactive materials of early nuclear accident plume in different surface layers.The results show that the pollution area near the surface of stack release in stable layer is the largest.The M-C model can simulate the evolution of early nuclear accident plume.  
        关键词：Nuclear accident;Plume;Mont-Carlo method   
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        发布时间：2021-03-05
      • YANG Lei1 LIU Ke2 LIU Yibao1 LIU Yujuan1 1
        Vol. 34, Issue 3, (2011)
        摘要：Based on previous studies,the application of plant growth simulation algorithm for source pencils deployment of 60Co irradiator is feasible.In this paper,with an improved theory for calculating the source pencil deployment,implementation of algorithm is greatly improved,too.Three cases of 60Co irradiator in various computation scales are demonstrated.The results show that using the new version of code,not only the pencil deployment quality but also the calculating efficiency are improved obviously,and its range of application is also enlarged greatly.With enhanced practicality,the code provides a dependable method for optimizing source pencil deployment of 60Co irradiators.  
        关键词：Improved plant growth simulation algorithm;Programming realization method;Practicality   
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        发布时间：2021-03-05
      • XI Shanbin1,3 WANG Zhikuan4 LU Wu1,2 WANG Yiyuan1,3 XU Fayue1,3 ZHOU Dong1,3 LI Ming1,3 WANG Fei1,3 YANG Yonghui4 1
        Vol. 34, Issue 3, (2011)
        摘要：In this paper,we investigate 60Co γ-ray irradiation effects and annealing behaviors of NPN bipolar junction transistors of the same manufacturing technology but different doping concentrations.The transistors of different doping concentrations differ in responses of the radiation effect.More degradation was observed with the transistors of low concentration-doped NPN transistors than the high concentration-doped NPN transistors.The results also demonstrate that reverse-biased transistors are more sensitive to radiation than the forward-biased ones.Mechanisms of the radiation responses are analyzed.  
        关键词：NPN bipolar transistor;60Co-γirradiation;Base doping concentration;Bias condition   
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        发布时间：2021-03-05
      • WU Hexi1 LIU Qingcheng1 YANG Bo1 YUAN Xinyu2 WANG Ling1 1
        Vol. 34, Issue 3, (2011)
        摘要：This work derived the relationship of the emanation factor and the radon that released from building materials based on the equation of balance for each phase of radon in unbroken building materials,and calculated the emanation factor of the radon that released from the top-surface of the building materials by measuring the concentration curve of radon in the equipment at intervals.The radon attenuation in air-filled pores of building materials is taken into account.The measuring results are more accurate after the calculation of leakage rate of the equipment by measuring the concentration of the pre-injected radon in the equipment at intervals.A high accurate measuring formula for short time is also obtained for the existing of "back-diffusion" in long time measuring,which can accurately fit the experimental data within ±4%.  
        关键词：Building materials;Radon emanation factor from top-surface;"Leakage" and "Back-Diffusion"   
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        发布时间：2021-03-05
      • QIAO Wenli1 ZHAO Jinhua1 SHAO Xiaoxia2 ZHANG zhiyong3 LIU Xingfeng3 WANG Taisong1 JIN Wenya1 YAO Yuping1 1
        Vol. 34, Issue 3, (2011)
        摘要：In this work,we explored the method of radiolabeling scorpion toxin peptide BmK CT,and investigated the stability,the ability of cell conjugation of 131I-BmK CT,and its distribution and imaging in glioma-bearing Wistar rats.After cloning,expression,and purification,BmK CT was labeled with 131I by indirect labeling(Bolton -Hunter method).131I-BmK CT was injected into the tail vein of glioma-bearing rats,and imaged at 1,4,8,24 and 48 h.The rats were sacrificed by cervical dislocation,and tissue samples were studied.131I-BmK CT was successfully prepared with the overall yield of 37.8 ±8.9%.The radiochemical purity was more than 95%.The specific binding efficiency of 131I-BmK CT with C6 glioma cell was 39.62%.In the first 24 h after injection,the bio-distribution in rats showed rapid blood clearance.Most of the radioactivity was observed in liver,lung and kidney.After 24 h,the bio-distribution showed renal clearance,especially at the peak time of accumulation,when the tumor could be viewed clearly.The largest uptake ratio of tumor to non-tumor(background)(T/NT) at 4 h was 6.79 ±0.29.In conclusion,131I-BmK CT can be prepared and specifically conjugate with C6 glioma cell.Good bio-distribution was observed in glioma-bearing rats.Nevertheless,great deal of research work needed to be done before clinical application of the medicine.  
        关键词：BmK CT;Isotope labeling;Rat;Biodistribution   
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        发布时间：2021-03-05
      • HU Shanshan WU Hubing WANG Quanshi WANG Mingfang ZHOU Wenlan LI Hongsheng WANG Lijuan
        Vol. 34, Issue 3, (2011)
        摘要：In this work,positron emission tomography/computed tomography(PET/CT) with 18F-fluorodeoxyglucose(18F-FDG) was evaluated for detecting recurrence and metastasis of colorectal cancer.18F-FDG PET/CT was studied in 63 patients with colorectal cancer after surgery.The diagnosis of recurrent tumor and/or metastasis was based on pathologic examination,multi-modality imaging and clinical follow-up for over six months.The diagnostic competent of PET/CT was assessed by comparing the clinical findings.In a total of 63 patients,recurrent and/or metastasis tumors were proved in 45 patients.Based on the patient number,the sensitivity,specificity and accuracy of PET/CT in detecting recurrent tumor and/or metastasis were 95.6%,83.3% and 92.1%,respectively.Based on the lesions,the sensitivity,specificity and accuracy of PET/CT were 96.9%,66.7% and 95.7%,respectively.More lesions were detected by 18F-FDG PET than CT(χ2=6.449,P=0.011).Combining 18F-FDG with PET/CT changed the re-staging of 13 patients(20.6%),with upstaging in 12 patients and down-staging in one patient.It can be concluded that 18F-FDG PET/CT has an important clinical value in detecting recurrent tumor and/or metastasis of colorectal cancer.  
          
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        发布时间：2021-03-05
      • WANG Lili QIN Songbing LOU Cheng XU Xiaoting ZHOU Juying
        Vol. 34, Issue 3, (2011)
        摘要：For evaluating the potential of 18F-FDG uptake rate to monitor biological responses of irradiated tumor cells,18F-FDG uptake rates were detected for A549 and MCF-7 cells irradiated by 6 MV X-rays to,1,2,4,6,8 and 10 Gy single dose.Also,18F-FDG uptake rates of A549 and MCF-7 cells after 8 Gy single dose irradiation were detected at 1,2,3,4,5 and 6 d,and 1,2 and 3 w.The cell survival rate was detected by MTT.The cell cycles and apoptosis rate were detected by flow cytometry to evaluate tumor cell growth inhibition by ionizing radiation.Clonogenic assay was used to measure the survival fraction.The data were analyzed by the statistical software SAS8.0.The results showed that 18F-FDG uptake rate of A549 and MCF-7 cells decreased with increasing single doses.The 18F-FDG uptake rate after irradiation of different doses was negatively correlated with the apoptosis rate(r =– 0.96,P<0.005),and positively correlated with G2/M%+S% and survival fraction(r =0.96;0.93,P <0.01.r =0.94;0.96,P <0.005).At different time after the single exposure of 8 Gy,the 18F-FDG uptake rate of A549 and MCF-7 cells gradually increased to reach the peak,then decreased.The cell viability was positively correlated with 18F-FDG uptake rate(r=0.78;0.86,P<0.05).It can be concluded that 18F-FDG uptake rate correlated with the changes of biology effect of tumor cells after irradiation,and it may be used to evaluate for irradiation effects of tumor cells.  
        关键词：18F-FDG uptake rate;Tumor cells;Ionizing radiation   
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        发布时间：2021-03-05
      • FU Zaiwei1,2 QIAN Sen2 NING Zhe2,3 WANG Yifang2 HENG Yuekun2 WANG Zhigang2 CHEN Xiaohui2 LIU Shudong1 QI Ming1 ZHANG Jiawen2 ZHENG Yangheng3 1
        Vol. 34, Issue 3, (2011)
        摘要：Based on a VME DAQ system under Windows XP environment,performance of a photomultiplier tube(PMTs),which will be used in the T0 system for the beam test experiment of the MRPC(multi-gap resistive plate chamber),were carefully measured.The high voltage of PMT was confirmed by studying its single photoelectron spectrum,from which the performance of PMT(such as energy resolution of the charge spectrum,peak-to-valley ratio and gain) could be acquired.The time resolution of T0 was improved by distributing the data with different number of photon which depend on the charge distribution,  
        关键词：VME;T0;PMT;High time resolution   
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        发布时间：2021-03-05
      • MA Yichao WU Jie ZHANG Jie SONG Hongzhi KONG Yang
        Vol. 34, Issue 3, (2011)
        摘要：In this paper,the principle of the synchronous protocol of the IEEE1588 is analyzed,and the factors that affect the accuracy of synchronization is summarized.Through the hardware timer in a microcontroller,we give the exactly the time when a package is sent or received.So synchronization of the distributed clocks can reach 1 μs in this way.Another method to improve precision of the synchronization is to replace the traditional fixed frequency crystal of the slave device,which needs to follow up the master clock,by an adjustable VCXO.So it is possible to fine tune the frequency of the distributed clocks,and reduce the drift of clock,which shows great benefit for the clock synchronization.A test measurement shows the synchronization of distribute clocks can be better than 10 ns using this method,which is more accurate than the method realized by software.  
        关键词：PTP;Synchronization;Frequency synchronization;VCXO;Sensor network;Distributed data acquisition   
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        发布时间：2021-03-05
      • ZHANG Cuiyun ZHANG Junxia MA Linna ZHANG Sheng YIN Miying LI Zhenghong
        Vol. 34, Issue 3, (2011)
        摘要：A measurement technique of the denitrifier method,which was developed for seawater isotopic analysis,was established for analyzing nitrogen isotopic composition of nitrate in groundwater and the vadose zone sediments.Experiments were conducted using international isotopic standards of IAEA-N3 and USGS34 and field samples.δ15N analyses of the two isotopic standards showed good reproducibility,with an average precision of 0.25‰(ranging from 0.1‰ to 0.5‰).Groundwater and sediment extracts were accurately reproduced,with precisions of better 0.5‰.The results showed that the measurement technique of the denitrifier method could be used for analyzing nitrogen isotopic composition of nitrate in groundwater and sediments.A case study using the technique showed that a thick vadose zone sediment profile had no increase trend of δ 15N values in depths below the vadose zone,indicating little denitrification occurrence.  
        关键词：Denitrifier method;Nitrogen isotopes;Groundwater;Sediments   
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        发布时间：2021-03-05
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