最新刊期
      卷 39 ， 期 11 ， 2016

        NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH

      • Weiwei WANG,Xingbi REN,Lidong XIA,U Mingming Y,Hairong LI,HANG Weiguang Z,Xiaosong ZHOU
        Vol. 39, Issue 11, Article number: 110501(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110501
        摘要：Background The cryogenic properties of hydrogen isotopes are affected by ortho-para ratio of the homonuclear molecules (H2, D2, T2). Purpose It is necessary to determine the ortho-para ratio. Methods A cryogenic elution chromatographic method for determination of the ortho-para ratio is established, in which an activated alumina porous layer open tubular (PLOT) column with 30 m×0.53 mm×20 μm was applied for separation of the spin isomers. Results The isomers were well separated at base line (the resolution Rs>1.5) at temperature of liquid nitrogen (78 K), compared with the conventional packed columns. When the Neon carrier rate is 5 mL·min-1, the resolution of ortho-para protiumRs (o-H2, p-H2) and ortho-para deuterium Rs (o-D2, p-D2) is 6.9, 1.8, respectively. Conclusion The resolution is affected by sample content and flow rate. According to integration of peak areas, the ortho-para rate at 300 K for protium and deuterium is 2.77:1, 1.78:1, respectively, which is in accordance with the theoretical results. Partial separation is obtained between ortho-H2 and HD, and the resolution Rs (o-H2, HD) reached 0.4, theoretical plates of 3.9×105 should be required to achieve the baseline separation (Rs=1.5).  
        关键词：Hydrogen isotopic spin isomers;Ortho-para ratio;Gas chromatography;Activated alumina;PLOT column   
        24
        |
        11
        |
        2
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298485 false
        发布时间：2021-05-24
      • Yixuan ZHANG,Yang LI
        Vol. 39, Issue 11, Article number: 110502(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110502
        摘要：Background Metal oxide clusters are very important inorganic materials, which are widely used in catalytic reactions. And neutron scattering is an important technique for the study of the condensed matters and materials. Purpose The aim is to study the dynamics of the polymer chain confined in metal oxide cluster molecules. Methods Quasielastic neutron scattering technique is employed to measure the dynamics of the sample. A theoretical model, which assumes that the vibrational, translational and rotational motions are independent of each other, is used to analyze the neutron spectra. Results The dynamics of the polymer chain confined in metal oxide cluster are highly restricted in space. The large-scale motion of the chain is greatly hindered. The rotations of the methyl group and methylene group are also slowed down. Conclusion The metal oxide cluster exhibits ultra-confinement effect on the polymer chains.  
        关键词：Neutron scattering;Metal oxide cluster;Dynamics   
        30
        |
        11
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298389 false
        发布时间：2021-05-24

        NUCLEAR ELECTRONICS AND INSTRUMENTATION

      • Fuzhen XU,Hongguan YANG,Jinfan CHANG,Xiang LIU
        Vol. 39, Issue 11, Article number: 110402(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110402
        摘要：Background The air shower core detector array (SCDA) is one of the important detectors to be constructed at the heart of the KM2A (one kilometer square extensive air shower array) with the area of 5 000 m2, in large high altitude air shower observatory (LHAASO). Purpose This study aims to design the readout electronics of SCDA for accurate charge measurement of the input photomultiplier tube (PMT) signal for three orders of magnitude. Methods A 50-Ω impedance match between the "virtual" grounding and input end is employed to measure the charge by the charge integration method. The feasibility of impedance match is verified by "Pspice" simulation tool. The output current signal from the PMT is collected and processed by the readout electronics of charge integration circuit via coaxial cable. Results The performance testing in the laboratory shows that the designed circuit satisfies design requirements of the long-distance and large-dynamic-range charge measurement. Conclusion The simulation and testing of "virtual" grounding impedance match validate the feasibility of this circuit. The readout electronics fulfills the application requirements of SCDA.  
        关键词：LHAASO;SCDA;Charge integrator;Impedance match;Dynamic range   
        22
        |
        11
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298407 false
        发布时间：2021-05-24
      • Xu HONG,Shijun NI,Jianbin ZHOU,Yingjie MA,Yi LIU,Wei ZHOU
        Vol. 39, Issue 11, Article number: 110403(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110403
        摘要：Background The Gaussian pulse possesses the advantages of time response, frequency response and signal-to-noise ratio (SNR), thereby nuclear signal is usually shaped to Gaussian or Semi-Gaussian pulse shape. Purpose This work aims to simulation study on Gaussian pulse shaping algorithm and discuss the influence of shaping parameters on the amplitude and width of the shaped pulse. Methods The cutoff frequency and quantify factor are introduced into Gaussian pulse shaping algorithm. The filtering performance of the algorithm and its effects on amplitude spectrum are evaluated and compared with the trapezoidal pulse shaping algorithm. Results The simulation results suggest that Gaussian pulse shaping algorithm has better performance than trapezoidal pulse shaping algorithm in filtering when the peaking times of the shaped pulses are equal. Also, Gaussian pulse shaping algorithm can reduce the full width at half maximum (FWHM) of nuclear signal amplitude spectrum. Conclusion Combined with the trapezoidal pulse shaping algorithm, the defect of Gaussian pulse shaping algorithm in pile-up pulse separation can be improved to increase output stream of nuclear signal.  
        关键词：Gaussian pulse shaping;Trapezoidal pulse shaping;Nuclear signal;Full width at half maximum   
        144
        |
        27
        |
        7
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298513 false
        发布时间：2021-05-24
      • Xiaomin LIU,Huiqiang JIANG,Zhiyu WANG,Tong LIU,Hua CHEN,Liping WANG,Faxin YU
        Vol. 39, Issue 11, Article number: 110401(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110401
        摘要：Background The digital to analog converter (DAC) used in space-borne electronic system is unavoidable to be affected by the radiation, and it is essential to evaluate the DAC performance before formal application. Purpose This study aims to develop an automatic measurement system of high-accuracy and high-speed for radiation-tolerance evaluation of space-borne D/A converters. Methods Based on the peripheral component interconnection extensions for instrumentation (PXI), Kelvin (4-wire) method and mean filtering algorithm are applied to accurately monitor the voltage and current of the DAC chip, and a switch matrix configured in software is adopted to automatically switch over measurements of different parameters. Meanwhile the PXI bus synchronization and trigger mode control are used to achieve high-speed response among modular instruments, and the cubic spline algorithm is performed to accurately extract the single event saturated cross section and linear energy transfer threshold. Results The identified voltage precision is 0.1 μV, and the DAC monitoring precision is up to 24 bit. In single event effects evaluation, the monitoring frequency of current variation and register upset are 50 Hz and 100 Hz respectively, and for total dose effect evaluation, only 8-s ergodic time are needed to measure all characteristic parameters. Conclusion The designed measurement system can evaluate the performance of space-born DAC fully automatically and efficiently with high precision, which is a reference solution to such similar research.  
        关键词：Digital to analog converter;Total ionizing dose;Single event effects;LabVIEW   
        47
        |
        11
        |
        1
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298518 false
        发布时间：2021-05-24

        SYNCHROTRON RADIATION TECHNOLOGY AND APPLICATIONS

      • Guoqing ZHANG,Mingmei ZHANG,Shaofeng WANG,Yongfeng JIA
        Vol. 39, Issue 11, Article number: 110103(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110103
        摘要：Background One of the most important pollution sources of arsenic is the oxidation dissolution of arsenopyrite in oxygen-bearing solution. Purpose This work investigated the oxidation process and product of arsenopyrite in O2-bearing solution using batch experiment. Methods The influences of pH and dissolved oxygen (DO) on the oxidation dynamics of arsenopyrite are investigated. Besides that we also analyze the transformation of arsenic in the process of the oxidation of arsenopyrite using X-ray Absorption Fine Structure (XAFS). Results XAFS spectroscopy data shows that, at pH=4, the oxidation of arsenopyrite is intensive and the released As(V) would be absorbed by iron oxide formed in the process of oxidation; at pH=7, the released As(III) would be absorbed by iron oxide and a few realgar analogues appear in the surface of arsenopyrite; at pH=9, the oxidation of arsenopyrite almost does not occur, but only a small amount of thioarsenates exhibit in the surface of arsenopyrite. Conclusion The pH is the most important parameter controlling the oxidation of arsenopyrite. The oxidation of arsenopyrite is inhibited in neutral and alkaline conditions, due to the formation of Fe oxides on the surface of arsenopyrite quickly.  
        关键词：Arsenopyrite (FeAsS);Oxidation reaction;Iron oxides coatings;XAFS   
        20
        |
        11
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298229 false
        发布时间：2021-05-24
      • Chunpeng WANG,Zijian XU,Xulei TAO,Renzhong TAI
        Vol. 39, Issue 11, Article number: 110102(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110102
        摘要：Background In most commonly used iterative phase retrieval algorithms in X-ray ptychography, the incident X-ray is considered to be fully coherent and monochromatic (i.e. in single state), the sample is considered to be stable or unchanged, and the responses of all optical elements in the system are considered to be fixed throughout the data acquisition process. However, in actual experiments, the above three conditions cannot be guaranteed simultaneously. Under non-ideal conditions, decoherence effects from single state changing or states mixture could severely deteriorate the reconstructed image quality. Purpose This study aims to improve the reconstructed image quality using mixed states decomposition iterative phase retrieval algorithms to eliminate the negative influences of various types of decoherence effects. Methods Two mixed state decomposition algorithms, the multi-mode extended ptychographical iterative engine (Mm-ePIE) algorithm and the sub-pixel up-sampling extended ptychographical iterative engine (Us-ePIE) algorithm are used to reconstruct the sample function and the probe function(s) simultaneously. Results The results show that the decomposition effect of state mixture from different sources is embodied in both the reconstructed sample function and probe function(s). Conclusion These two mixed-state decomposition phase retrieval algorithms can both improve the quality of the reconstructed image significantly. Moreover, the multi-mode algorithm performs better than the up-sampling algorithm in removing the decoherence effects.  
        关键词：X-ray ptychography;Mixed state;X-ray microscopy;Iterative phase retrieval algorithm   
        16
        |
        12
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298257 false
        发布时间：2021-05-24
      • Hongliang QIN,Yan ZHAO,Nan WANG,Wanqian ZHU,Zhongmin XU
        Vol. 39, Issue 11, Article number: 110101(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110101
        摘要：Background BL19U canted beamlines whose light sources were located at the same straight section in the storage ring were built at Shanghai Synchrotron Radiation Facility (SSRF) as the first canted beamlines. Purpose The space is very limited for the layout of canted beamline components, because the horizontal angle between the two beamlines is only 6 mrad. Methods In order to achieve the layout for canted beamlines, it is essential to put the key components in succession, share the same chamber and set reflecting mirrors on the beamlines. Complicated layout and detailed specifications for the key components on canted beamlines are presented and discussed. Results & Conclusion They have been operated more than 6 000 h without any mechanical failure since the beginning of 2015.  
        关键词：Synchrotron radiation;canted beamlines;Beamline layout   
        30
        |
        12
        |
        2
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298285 false
        发布时间：2021-05-24

        LOW ENERGY ACCELERATOR, RAY AND APPLICATIONS

      • Hexi WU,Liangquan GE,Yaoyao LUO,Yibao LIU,Fei YU
        Vol. 39, Issue 11, Article number: 110201(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110201
        摘要：Background It is difficult to establish the least square method for parsing airborne gamma-ray spectrum because the approximately infinite stratum does not exist when it contains only 235U and 238U series, 232Th series or 40K. Purpose This study aims to acquire the response spectrum of airborne gamma-ray spectrometry (AGS) by Monte Carlo simulation and establish the above-described method. Methods Based on the principle of media interchange, the basic thought of modular stratum and energy partitioning for characteristic gamma-ray, the combination model is used to obtain the AGS' response spectrum of any shape of stratum by Monte Carlo simulation. And the least square model for solving airborne gamma-ray spectrum is established by the above response spectrum. Results The corrected model of eU, eTh and 40K content in stratum is acquired by analyzing the eight airborne gamma-ray spectra from the dynamic scale model in Shijiazhuang City. The calculation values of 10 km survey lines coincide with the specification for AGS when the content of natural radioactivity nuclide is larger than 4×10-6. Conclusion The results verify that the calculation model is a valid analytical technique of AGS for natural radioactivity nuclide in stratum. And it provides a valid method to acquire the AGS' response spectrum of artificial radioactivity nuclide.  
        关键词：Airborne gamma-ray spectrometry;Monte Carlo simulation;Least square method   
        22
        |
        10
        |
        3
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298272 false
        发布时间：2021-05-24

        NUCLEAR CHEMISTRY, RADIOCHEMISTRY, RADIOPHARMACEUTICALS AND NUCLEAR MEDICINE

      • Jianchao HE,Heyi WANG,Chengjian XIAO,Jiamao LI,Jingwei HOU,Xiulong XIA
        Vol. 39, Issue 11, Article number: 110301(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110301
        摘要：Background Pt/PTFE/foam-SiC-structured hydrophobic could be used for a water detritiation system (WDS) via a liquid-phase catalytic exchange process (LPCE). Purpose To study the influence of impregnation solution on the performance of this catalyst, acetone, ethylene glycol and ethanol were chosen as the solvent to prepare Pt-organic solution, respectively. Methods The catalysts were prepared by impregnation method with the above three different solutions. The as-prepared catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscope (TEM), etc. Moreover, their catalytic activity for LPCE was tested. Results The average particle sizes of Pt particles of the three different catalysts were 9.3 nm, 3.6 nm and 6.8 nm, respectively. The catalyst prepared by chloroplatinic acid-ethylene glycol had the smallest average particle size, because ethylene glycol would protect Pt particles. Three valences, Pt(0), Pt(II) and Pt(IV) existed in these catalysts, and Pt(0) was the key for catalytic isotope exchange. Pt(0) was the main valences in the catalysts prepared by chloroplatinic acid-ethanol and chloroplatinic acid-ethylene glycol, and the proportion were 47.60% and 43.97%, respectively. Pt(IV) was the main valence in the catalyst prepared by Chloroplatinic acid-acetone. According to the results of LPCE, the catalyst prepared by chloroplatinic acid-ethylene glycol had the highest column efficiency. Conclusion The results meant that when the proportions of Pt(0) are close, the Pt particle size was the main factor of influence on LPCE. Thus, ethylene glycol is the best solvent.  
        关键词：Pt/PTFE/foam-SiC;Hydrophobic catalyst;LPCE;Dipping solution   
        25
        |
        11
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298277 false
        发布时间：2021-05-24

        NUCLEAR ENERGY SCIENCE AND ENGINEERING

      • Wei LI,Guanghui SU,Suizheng QIU,Wenxi TIAN,Ping CHEN,Yuanming LI
        Vol. 39, Issue 11, Article number: 110601(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110601
        摘要：Background RELAP5 has been widely used in the field of nuclear thermal-hydraulics and safety analysis. However, improvement issues in terms of numerical stability and accuracy exist due to its basic single-pressure two-fluid model. Purpose This study aims to enhance the numerical stability and numerical accuracy of RELAP5 by modifying the mathematical structure of RELAP5 basic model. Methods Firstly, the default mathematical expression of the virtual mass force was modified in the RELAP5 code. Secondly, an interface pressure term was incorporated in the code, and a total variation diminish (TVD)-type flux limiter method was implemented in the RELAP5 code in place of the default 1st-order upwind scheme for the convective terms in mass and energy conversation equations. Results In a numerical test where the evolvements of void fraction perturbation were concerned, the modified RELAP5 predicted no growth of the perturbation amplitude in contrast to a rapidly developing divergence for the default RELAP5. In addition, for the phase segmentation problem, convergence was accomplished on finer mesh by the modified RELAP5, while non-physical distribution of the void fraction was rendered by the default RELAP5 especially for finer mesh. When applied to the Ransom water faucet numerical test and Marviken CFT 15 experiments, the improved RELAP5 with 2nd-order of accuracy was more reliable in that the predictions were closer to the experimental results. Conclusion Compared with the original RELAP5, the modified or improved RELAP5 showed evident numerical stability and accuracy during the assessment in this work.  
        关键词：RELAP5;Stability;Accuracy;Hyperbolicity;Virtual mass;Interface pressure   
        30
        |
        10
        |
        1
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298564 false
        发布时间：2021-05-24
      • Huiwen XIAO,Guoming LIU,Hong YAO,Xin GAO
        Vol. 39, Issue 11, Article number: 110602(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110602
        摘要：Background With the development of energy industry, nuclear power is confronted with more challenges in peak load operation. CNP600 is the substantial of active service reactors, and the evaluation of CNP600 in low power operation is of great necessity. Purpose The aim is to evaluate whether the CNP600 can meet the neutronics safety requirements of extended low power operation (ELPO). Methods The influences of ELPO on the reactor physics was analyzed in this paper, including axial and radical power distribution, shutdown margin, enthalpy rise factor F△H, power peak factor FQ, burnup, and liner power density. Results The results indicate that the ELPO has little impact on radical power distribution, but profound impact on axial power distribution which could remain stable by the movement of control rod yet; the shutdown margin, F△H and FQ, burnup, liner power density are lower than the limit values. Conclusion The CNP600 can meet the neutronics safety requirements of ELPO.  
        关键词：Extended low power operation;CNP600;Reactor physics   
        21
        |
        12
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298606 false
        发布时间：2021-05-24
      • Lu LI,Jingyu ZHANG,Qingyang GUO,Yixue CHEN
        Vol. 39, Issue 11, Article number: 110603(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.110603
        摘要：Background Activated corrosion products (ACPs) from structure materials and coolant activation products are the dominant radiation hazard in water-cooled fusion reactor under normal operation conditions, and directly determine the occupational radiation exposure (ORE) during operation and maintenance. Purpose The aim is to quantitatively analysis source term of activation products in International Thermonuclear Experimental Reactor (ITER). Methods CATE V2.1 is used to simulate the ACPs from structure materials and coolant activation products in the ITER blanket circuit, and then the dose rate of the LIM-OBB (Limiter-Out-Bboard Baffle) cooling loop operating for 1.2 a, and 15 d after shutdown is calculated by point kernel code ARShield. Results & Conclusion Under operation conditions, the specific activity and dose rate of the coolant activation products are much higher than those of ACPs from structure material, while after shutdown, the coolant activation products decay out rapidly, and the ACPs from structure material become the main contributor to specific activity and dose rate.  
        关键词：Activated corrosion products from structure materials;Coolant activation products;ITER;CATE 2.1   
        24
        |
        13
        |
        4
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 10298607 false
        发布时间：2021-05-24
      0