最新刊期
      卷 0 ， 期 0 ， 2020
      • ZHANG Bin1 LI Min1 WANG Jianzhong1 SHI Liqun1 CHENG Huansheng1 YANG Tieying2 WEN Wen2 HU Fengchun3 1
        Vol. 35, Issue 5, (2012)
        摘要：Mn-doped ZnO films were prepared by radio frequency magnetron sputtering on sapphire substrate at different temperatures.They contained Mn of 5 at.%,without any magnetic impurities of Fe,Co and Ni,as were revealed by proton induced X-ray emission(PIXE).Synchrotron radiation X-ray diffraction(SR-XRD) showed that the ZnO:Mn films possessed the wurtzite ZnO structure.No precipitates such as Mn cluster or MnO,MnO2,Mn2O3,and Mn3O4were observed by SR-XRD and fluorescence extended X-ray absorption fine structure spectra(EXAFS) in ZnO:Mn films.EXAFS analysis also showed that Mn atoms were incorporated into ZnO crystal lattice by occupying the sites of zinc atoms.  
        关键词：SR-XRD;EXAFS;Mn-doped ZnO film;Microstructure   
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        发布时间：2021-03-05
      • HUANG Linfei1,2 YU Feng1 XU Chunyan1 TANG Lin1 HE Jianhua1 1
        Vol. 35, Issue 5, (2012)
        摘要：For the ubiquitous distribution and high toxicity in the ecosystem,arsenic contaminants have been a world-wide public health problem for decades.The enzyme ArsM has the ability of methylating the inorganic arsenite.To study mechanism of the process,the recombinant ArsM from Rhodopseudanonas palustris(RpArsM) was expressed,purified and crystallized.The RpArsM crystals were examined by X-ray crystallography on Beamline BL17U1 at Shanghai Synchrotron Radiation Facility,and the diffraction data were processed to a resolution of 2.0.The results show that the RpArsM crystals are of the P212121space group,with unit-cell parameters a=45.92,b=66.58,c=147.82 and α=β=γ=90°.  
        关键词：Rhodopseudanonas palustris;ArsM;Crystallization   
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        发布时间：2021-03-05
      • WANG Haiyang YAO Tao LIU Shoujie CHEN Xiangcun KANG Chaoyang SUN Zhihu WEI Shiqiang PAN Guoqiang
        Vol. 35, Issue 5, (2012)
        摘要：Ag@Au core-shell nanoparticles were synthesized via chemical liquid phase reduction method.They were characterized by UV-Vis absorption spectroscopy,transmission electron microscopy(TEM),differential scanning calorimetry(DSC) and X-ray absorption fine structure(XAFS) spectroscopy.The Ag@Au nanoparticles are of uniform and stable monodisperse,with an average size of the Ag core of about 8 nm,and the Au shell thickness of about 3.5 nm.DSC spectra show that core-shell particles are the most dramatic diffusion in the alloying process around 300°C,and the alloy is completely formed at 500°C.From the high temperature in-situ XAFS and the RSF curves,significant changes are clearly seen in the local structure of Au atoms in the alloying process.By fitting the data with replacement method,the Au-Au bond length gradually becomes longer from 2.86 to 2.89 and the coordination bond from 8.0 to 6.1,with 2.1 Au-Ag coordination bonds and increased degree of disorder,at the alloy formation.The alloy process is mainly based on subrogation diffusion.  
        关键词：Ag@Au core-shell nanoparticles;High temperature in-situ XAFS;Alloying process;Synchrotron radiation   
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        发布时间：2021-03-05
      • ZHANG Ning LENG Yongbin CHEN Zhichu YUAN Renxian LAI Longwei
        Vol. 35, Issue 5, (2012)
        摘要：A bunch-by-bunch beam position monitor system,based on a broadband oscilloscope embedded EPICS IOC,has been developed at SSRF to study the beam instabilities driven by the wake-field effects.The horizontal and vertical beam positions of each bunch could be located independently in this system by using the original signals from the button-type pickups on the storage ring.In this article,we report the hardware and software architecture of this system.The bunch-by-bunch data of the storage ring are used to evaluate performance of the system.Dependency of the tune,and the betatron oscillation amplitude of different bunch on the corresponding bunch ID,is also detected.The system is an effective tool for machine-study of SSRF.  
        关键词：Beam instability;Bunch-by-bunch measurement;Beam diagnostics;Wake-field;SSRF   
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        发布时间：2021-03-05
      • ZHU Haijun LIU Yajuan YUAN Qibing
        Vol. 35, Issue 5, (2012)
        摘要：EPICS-based systems design to realize remote control of injection and extraction in SSRF are reported in this paper.The system operational principle and hardware configuration are expatiated,and schematics of the remote control system and its method of design are described.Application results show that system has high detection precision and sensitivity,occupies fewer resources,and works stably.The system satisfies the control requirement.  
          
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        发布时间：2021-03-05
      • YI Xing1,2 LENG Yongbin1 LAI Longwei1 ZHANG Ning1 YAN Yingbing1 1
        Vol. 35, Issue 5, (2012)
        摘要：Digital beam position monitor processor is the key part of a beam position system.A BPM processor based on software radio is much better than traditional processors in terms of the resolution and flexibility.In this paper,we report technical specifications and design considerations of the digital beam position monitor developed at Shanghai Synchrotron Radiation Facility(SSRF).The turn-by-turn electronic resolution of the processor is better than 1.5 μm,when the input power is larger than –30 dBm,and the resolution is better than 2 μm in a test in the SSRF storage ring,with the beam current of over 150 mA.  
        关键词：Beam position monitor;Software radio;Digital down convertor;SSRF   
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        发布时间：2021-03-05
      • DU Jifu1,2 HUANG Ningkang2 1
        Vol. 35, Issue 5, (2012)
        摘要：Optical waveguide was fabricated by implanting 3 MeV oxygen ions of 5×1014and 1.5×1015ions/cm2into congruent lithium niobate(LN) crystals and annealing them at 200°C–500°C.Optical spectrum was used to investigation defects in the optical waveguide.The results revealed the reduction of Li ions in the implanted LN crystals.The absorption of LN crystal increased with the dose of oxygen ion.This showed that the color centers were formed increasingly with the oxygen ion dose.The color centers and defects affecting the optical absorption include oxygen vacancy,exciton,interstitial atoms and electrons captured by Nb ions occupying the Li ion site.The color centers and defects caused increase of the absorption in the implanted the LN crystals.The annealing temperature seemed to have little effect on reduction of color centers.The optical waveguide of the implanted LN crystal exhibits high temperature stability.  
        关键词：Ion implantation;Optical waveguide;Color center   
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        发布时间：2021-03-05
      • XUE Yuxiong1 YANG Shengsheng1 GUO Guang2 BA Dedong1 AN Heng1 TIAN Kai1 CAO Zhou1 SHI Shuting2 SHEN Dongjun2 1
        Vol. 35, Issue 5, (2012)
        摘要：ingle-event phenomena(SEP) is the malfunction of micro electronics devices caused by impact of an energetic heavy ion.To better elucidate the mechanisms,we measured the fast transient current resulting p-n junctions irradiated by pulsed laser.Pulse height spectra were generated to observe the spatial variations of charge collection properties.The transient current and charge collection varied at different laser energies.The charge collection was uniform within a sensitive area of the p-n diode,but it decreased in areas close to the edges.It was found that the collected charge(Q) was correlated with the laser energy(E) by Q=1.2579 E4/3.The charge generation data were compared with those obtained on a tandem accelerator with micro-beam of32S ion.  
        关键词：p-n junction;Pulsed laser;Charge collection;Single-event effect   
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        发布时间：2021-03-05
      • CAO Zhen1 LI Sa2 ZHANG Wenzai1 ZHAO Huali3 FENG Gensheng1 WANG Xiaojing1 1
        Vol. 35, Issue 5, (2012)
        摘要：Dosimetry parameters of Model 6711 125I seed source was simulated by using MCNP5,with a new geometric model of the 125I seed source and a new photon section data(mcplib04).Comparing to the AAPM TG-43U1 recommendation,our simulation results are satisfactory: the dose rate constant is in agreement within 0.62%,and the radial dose function within 0.15% to 5.12%.  
        关键词：Monte-Carlo method;Dosimetric characteristics;125I seed source   
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        发布时间：2021-03-05
      • ZUO Guangxia HE Bin XU Peng QIU Xiaolin MA Wenyan LI Sufen
        Vol. 35, Issue 5, (2012)
        摘要：In neutrons detection,it is important to discriminate the neutron signals from the gamma-ray background.In this article,simulation of neutrons and gamma pulse signals is developed based on the LabVIEW platform.Two digital algorithms of the charge comparison method and the pulse duration time method are realized using 10000 simulation signals.Experimental results show that neutron and gamma pulse signals can be discriminated by the two methods,and the pulse duration time method is better than the charge comparison method.  
        关键词：Simulation;Pulse shape discrimination;LabVIEW   
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        发布时间：2021-03-05
      • WU Xuemei1 TUO Xianguo1,2 LI Zhe1 LIU Mingzhe1,2 ZHANG Jinzhao1 LI Pingchuan1 SU Jilong1 1
        Vol. 35, Issue 5, (2012)
        摘要：Factors of airspeed,flux,activity,source position,pipe length and pipe diameter affect nonlinearly source activity readout of the Long Range Alpha Detection(LRAD).In this paper,multiparameter influence experiment is carried out using variable-control method,aiming at studying relationships between the readout and each of the factors.The back propagation(BP) neural network model is established to overcome the nonlinear effects of the factors on the readout,with the readout and the multiparameters being the input,and the source activity being the output.Experiment data of 948 groups are used for BP neural network forecasting,with an average relative error of 3.4218×10–4.And in a 100-group test,an average relative error of 2.217×10–2 is obtained.It shows that with this method source radioactivity in pipes can be simulated.  
        关键词：LRAD;Simulation facility;Multiparameter;BP neural network   
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        发布时间：2021-03-05
      • LIANG Qinglei LI Jinghuai LIU Guorong LI Anli
        Vol. 35, Issue 5, (2012)
        摘要：Time correlation coincidence(TCC) is an effective method to measure characteristics of fission materials.In this paper,MCNP code is used to simulate n/γ time-of-flight spectra(TOF) of a 252Cf spontaneous fission source detected by a BC-501A liquid scintillator.The results are in good agreement with the measured spectra.Therefore,n/γ TCC spectra of the 252Cf source are simulated.The results indicate that the n/γ TCC spectra are composed of the n-n,γ-γ,n-γ and γ-n coincidence.  
        关键词：MCNP code;252Cf spontaneous fission;n/γ time-of-flight spectra;Time correlation coincidence spectra   
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        发布时间：2021-03-05
      • LIU Xiaoqing1 LIU Bo1 MA Xinpeng2 1
        Vol. 35, Issue 5, (2012)
        摘要：In this paper,we report a high-precision intermediate-frequency digital phase detector.Suitable parameters for digital filter and other modules in the digital phase detector are chosen via careful analysis.The digital phase detector uses I/Q technology,and is achieved on FPGA chip,working as a part of experimental setup to detect the phase of intermediate-frequency signal.The results show that precision of the digital phase detector is 0.029°.The phase discrimination for one 3.71875 MHz signal is better than 0.05°,with a root mean square phase value of 0.0076°;while it is better than 0.1° with a root mean square phase value of 0.0287° for two 3.71875 MHz signals.  
        关键词：Digital phase detector;Digital filter;Digital I/Q;FPGA   
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        发布时间：2021-03-05
      • LI Jing PEI Hao LI Fan WANG Lihua FAN Chunhai
        Vol. 35, Issue 5, (2012)
        摘要：The addition of melamine into food caused serious social problems,hence the need of an easy way of detecting melamine and its derivatives.In this paper,we propose a new method based on the unique quenching effect of graphene oxide(GO).The difference of GO interaction with DNA and melamine is the basis of selective detection of melamine.GO adsorbs DNA and efficiently quenches the fluorescence of labeled fluorophores.The stronger interaction of melamine with GO than DNA leads to a competitive displacement of DNA out of the surface of GO,then a significant fluorescence increase appears.As a control,the glucose,maltose,and fructose do not cause significant fluorescence increase.This method is simple,inexpensive,sensitive and selective.It is suitable for rapid screening of large quantities of samples.  
          
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        发布时间：2021-03-05
      • BAI Lingzhi WANG Tingdong LIU Yue CHENG Cheng ZHANG Wei HUAI Ping
        Vol. 35, Issue 5, (2012)
        摘要：In this paper,we study the quantum confinement effect and effective Coulomb interaction in doped semiconductor quantum wire based on a two-band model.Single particle wave-function of carriers in T-shaped GaAs quantum wire can be obtained by finite-element solution of Schr dinger equation with complex boundary condition.The effective Coulomb interactions are calculated by using envelop function approximation.Due to their heavier mass,the quantum confinement effect of heavy holes is stronger than the electrons.The effective h-h Coulomb interaction increases with the intensity of electric field,while e-e Coulomb interaction decreases with increasing intensity of electric field.The e-h Coulomb interaction shows complicated dependency on electric field,which indicates competition of localization and delocalization characters in electron and hole.  
        关键词：Semiconductor quantum wire;Charge doping;Quantum confinement;Effective coulomb potential   
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        发布时间：2021-03-05
      • XIONG Wengang1,2 LI Wenxin1 WANG Min1 1
        Vol. 35, Issue 5, (2012)
        摘要：The decay products of 232U produced in the thorium-uranium fuel cycle emit high energy γ-rays.This affects the fuel cycle greatly.In this paper,the 232U productions in thermal reactor using thorium fuel are analyzed by ORIGEN2,SCALE5 and the code based on the Bateman method.Under normal situation,232U is mainly produced by 232Th(n,2n) reaction chain,and more quantity of 230Th can be transformed into 232U while the neutron spectrum is softer.The burnup calculation of CANDU reactor and PWR assembly indicates that the232U in uranium increase with the burnup,and230Th in fresh thorium has linear correlation with232U/Utotalor232U/233U at discharge burnup.  
        关键词：Thorium-uranium fuel cycle;232U;230Th;Neutron spectra;Molten salt reactor   
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        发布时间：2021-03-05
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