最新刊期
      卷 38 ， 期 11 ， 2015
      • CHEN Huabin,HU Jianzhong,ZHOU Jingyong,ZHENG Cheng,WANG Zhanwen,CHEN Can,CAO Yong,YIN Xianzhen,LYU Hongbin
        Vol. 38, Issue 11, Article number: 110101(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110101
        摘要：Background: Synchrotron radiation-based X-ray phase-contrast computed tomography (SR-XPCT) is an advanced tool for nondestructive analysis of three dimensional inner microstructure of samples, and plays an important part in the researches such as spinal cord microvasculature and lung bronchium. Purpose: This study was to investigate the three-dimensional morphology of fibrochondrocytes in rabbit patella-patellar tendon junction (PPTJ) using SR-XPCT, and develop an advanced imaging method. Methods: Three PPTJs were harvested from healthy mature female New Zealand rabbits. The specimens were scanned by SR-XPCT at BL13W1 of Shanghai Synchrotron Radiation Facility (SSRF) in China. The tomographic image was captured by Charge Coupled Device (CCD) detector with a 0.65-μm resolution. The three-dimensional visualization images of PPTJ were reconstructed by VG Studio Max. After that, the specimens were embedded by paraffin for Safranin O/Fast-green staining. Results: High-resolution three-dimensional visualization images of PPTJ and the parameters of the chondrocytes in fibrocartilage zone were successfully obtained via the SR-XPCT. With spherical and ellipsoidal morphologic features and its configuration characteristics in three dimension, the fibrochondrocytes revealed by SR-XPCT were consistent with the results of traditional histological staining. The parameters of chondrocytes showed that the mean diameter of chondrocyte was (10.139±1.265) μm, the mean volume was (291.187±87.283) μm3 and 75.4% of the chondrocytes’ volume ranged from 200 μm3 to 400 μm3, the mean sphericity degree was 0.711±0.079, and 84.9% of chondrocytes’ sphericity degree ranged from 0.605 to 0.805. Conclusion: The three-dimensional microstructure of the PPTJ was intuitively, accurately and undistortedly realized by the SR-XPCT, which may act as a novel instrument to access the three-dimensional microstructure changes during the PPTJ healing process.Cited  
        关键词：Synchrotron radiation;Phase contrast imaging;Bone-to-tendon junction;Fibrochondrocytes;Three-dimensional   
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        发布时间：2021-03-03
      • LI Yue,FAN Hongyu,YANG Ming,ZHANG Yiwu,NIU Jinhai
        Vol. 38, Issue 11, Article number: 110201(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110201
        摘要：Background: Due to their high melting point, high thermal conductivity, low sputtering yield, tungsten (W) and molybdenum (Mo) have been regarded as the potential candidates for plasma facing materials in fusion reactors. Purpose: This study aims to understand the irradiation damage behavior of W and Mo for the development of key fusion reactors materials. Methods: Polycrystalline W and Mo materials have been irradiated by 120-eV He ions with the irradiation temperature at 873 K. In situ analysis of these samples was carried out using nano-identation masked technique and non-destructive conductive atomic force microscopy (CAFM). The morphology, microscopic evolution and distribution of defects of these samples before and after irradiation are compared. Results: Analysis indicated that a large number of nanometer-sized helium bubbles were formed near the sample surface. Over-high internal pressure of nanometer-sized helium bubbles may result in forming protuberances of irradiated W and Mo. The section analysis of nano-identation showed that an obvious etching effect was founded on Mo materials. Conclusion: This work is of great significance for further understanding of the low-energy ion irradiation damage on plasma facing materials. Abstract  
        关键词：Irradiation damage;Tungsten;Molybdenum;Nano-identation;CAFM   
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        发布时间：2021-03-03
      • SUN Chaoming,TANG Guangping,LI Qiang,WANG Zengyong
        Vol. 38, Issue 11, Article number: 110202(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110202
        摘要：Background: Image quality in radiographic testing is often conditioned by the size and distribution of X-ray source. However, determination of focal spot is not performed effectively in practice, thus it is difficult to accurately control the image quality in the testing. Purpose: This study aims to obtain a quick and efficient test method to evaluate the focal spot for X-ray source. Methods: Test tools such as pinhole plate, star test pattern and duplex wire image quality indicator (IQI) were used to measure the focal spot of a portable X-ray source separately. Several measurements were carried out and compared in details. Results: Results of star test pattern and duplex wire IQI were coincident, but different from the results of pinhole imaging method obviously. Conclusion: Nominal focal spot size of an X-ray source may be considerably different from that in practice use, so it is necessary to timely evaluate characteristics of the focal spot. The duplex wire IQI can usually replace star test pattern to measure un-sharpness in radiographic testing images and to evaluate focal spot size. Abstract  
        关键词：Focal spot;Test and measurement;Pinhole imaging;Star test pattern;Duplex wire IQI   
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        发布时间：2021-03-03
      • CHENG Zhiqiang,LI Yangjuan,ZHANG Guoxin,ZHANG Huanqi,LI Sasa,DOU Qiang,LONG Dewu,WU Guozhong,LI Qingnuan
        Vol. 38, Issue 11, Article number: 110301(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110301
        摘要：Background: The fluoride volatility process has been developed to recover uranium from spent nuclear fuel. And the fluoride adsorption and desorption technique is usually applied to the purification of UF6 in the fluoride volatility process. Purpose: This study aims to investigate the adsorption mechanism of MoF6 on NaF adsorbent. Methods: The adsorption equilibrium and kinetics of MoF6 on NaF adsorbent at different temperatures and initial MoF6 pressure were experimentally studied by using statistic adsorption equipment. Langmuir adsorption model and adsorption kinetics model were applied to analyse experimental data. Results: The adsorption rate and equilibrium adsorption capacity of MoF6 on NaF adsorbent increased with the temperature increasing from 50 oC to 100 oC, and the adsorption capacity was 115 mg MoF6?g?1 NaF at 100 oC.The experimental data were fitted by pseudo-second-order kinetics as well as Langmuir adsorption model. Conclusion: The adsorption of MoF6 on NaF adsorbent was monolayer adsorption according to Langmuir adsorption model, and was controlled by diffusion of MoF6 inside NaF adsorbent which was not the unique rate-determining step, though. Abstract  
        关键词：NaF adsorbent;Gaseous fluoride;Adsorption isotherm;Adsorption kinetics;Intra-particle diffusion   
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        发布时间：2021-03-03
      • MIAO Xiaoli,LI Jihao,XIANG Qun,XU Jiaqiang,LI Linfan,LI Jingye
        Vol. 38, Issue 11, Article number: 110302(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110302
        摘要：Background: The separator is an important part of the battery, which prevents physical contact between electrodes during enable lithium ionic transportation. But most commercialized polyolefin porous membranes show low ion conductivity due to their inherent hydrophobic property and low porosity (45%). Purpose: The aim is to introduce polyacrylamide (PAAm) onto polypropylene (PP) separator, which could improve the affinity between nonaqueous electrolytes and electrodes. Methods: PP-g-PAAm separator was prepared by irradiation graft polymerization technique. The structure and the performance of pristine PP and PP-g-PAAm separator were analyzed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) from the aspects of mechanical property, liquid electrolyte uptake and lithium-ion conductivity. The coin cell was assembled in the Ar-filled glove box and investigated. Results and Conclusion: The results indicate that the coin cell with the PP-g-PAAm separator performs better than that one with the pristine PP separator under the same condition. Abstract  
        关键词：Lithium-ion battery;Polypropylene;Acrylamide;Irradiation graft;Separator   
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        发布时间：2021-03-03
      • SHAN Jian,LIU Xiaoxiang,XIAO Detao,LIU Wei,LIU Yan
        Vol. 38, Issue 11, Article number: 110303(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110303
        摘要：Background: 210Pb in air has yielded insight on the sources and transit times of aerosols. In an ideal enclosed air mass (closed system with respect to these nuclides), the residence times of aerosols can be obtained from the activity ratios of 210Pb/222Rn, 210Bi/210Pb, and 210Po/210Pb. Through measuring the activity-size distribution of 210Pb in the atmospheric particulates, it is conducive to the use of 210Pb tracer study in atmosphere. Purpose: This study aims to determine the activity-size distribution of 210Pb in the atmospheric particulates. Methods: Inhalable particles samples at different particle size levels were collected by M235 impact large flow classification sampler. The activity distribution of 210Pb in different particle size scales was determined by detecting β rays of 210Bi (the first generation progeny of 210Pb), and radioactivity of 210Pb was determined by using γ spectrometer, respectively. Results: Experimental results show that the distribution range of the specific activity (mBq·m?3) of 210Pb in atmospheric particulates is 0.0044–1.8321mBq·m?3 and the maximum are within 0.49–0.95μm size distribution. Conclusion: The activity-size distribution of 210Pb in the atmospheric particulates is mainly due to the effects of temperature, humidity, rainfall, wind speed, wind direction and other natural factors; the discrete of β counting measured data is larger than the discrete of γ counting measured data. Abstract  
        关键词：Activity of 210Pb;Activity-particle size distribution;Specific activity   
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        发布时间：2021-03-03
      • QIU Tingting,PENG Jia,HE Shuhua,ZHENG Xiaobei,LIU Yuxia,ZHOU Wei,ZHANG Lan
        Vol. 38, Issue 11, Article number: 110304(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110304
        摘要：Background: A varity of rare-earth fluorides can be produced with thorium uranium fuel circulating post-processing. These fluorides need to be dissolubled in solvent for seperation and contents measurement. Purpose: This paper aims to develop a fast and efficient pretreatment method to dissolve slightly soluble rare earth fluorides in nitric acid. Methods: Rare earth fluorides related to the thorium molten salt reactor (TMSR) fuel circulating post-processing including NdF3, EuF3, GdF3 and CeF3 were studied by using Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). After 2-h microwave digestion at temperature of 190 oC, the maximum solubility of these fluorides in 10 mL nitric acid (16 mol?L?1) is determined by ICP-AES. Results: The saturated concentration varies from 2.5 g?L?1 to 3.9g?L?1, which are two or three orders of magnitude higher than their solubility reported in previous literature. The standard deviation (n=3) of measurement by ICP-AES is under 4.2% and the linear correlation coefficient (r) is in the range of 0.999 47?0.999 96. Conclusion: An efficient chemical procedure for dissolving some rare earth fluorides has been developed. It provides a reference for pretreatment of insoluble rare earth fluorides in the solid molten salt samples of thorium uranium fuel circulating post-processing. Abstract  
        关键词：Microwave digestion;ICP-AES;Rare earth fluorides;Nitric acid;Dissolved   
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        发布时间：2021-03-03
      • ZENG Guoqiang,WEI Shilong,XIA Yuan,LI Qiang,XU Yadong,GE Liangquan,JIE Wanqi
        Vol. 38, Issue 11, Article number: 110401(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110401
        摘要：Background: CdZnTe (CZT) detector has excellent detection efficiency and resolution toward gamma ray at room temperature. It is a beneficial supplement to HPGe and scintillator detectors. Digital multi-channel analyzer (DMCA) plays significant role for high resolution spectrometer of CZT. Purpose: This study aims to overcome the effect of “hole tailing” for CZT detector by implementing digital nuclear signal processing system. Methods: A low noise charge sensitive amplifier is designed by considering optimal matching of detector and digital multi-channel analyzer. High speed analog-digital converter transforms the analog signal to discrete digital sequence signal. Digitized signals are processed by Field Programmable Gate Array (FPGA) chip in the DMCA. In this FPGA chip, fast-slow dual channel trapezoidal shaper and digital rise time discriminator are designed to overcome the problem of charge trapping of CZT detector. Digital rise time discriminator could eliminate the effect of “hole tailing” and improve the energy resolution of CZT detector. Results: For the 4mm×4mm×2.5mm capture plus structure of CZT detectors offered by Northwestern Polytechnical University, the best resolution is up to 3.6% for 241Am source, and up to 0.96% for 137Cs source. Conclusion: The optimal matching of each unit circuit in the whole digital nuclear signal processing system could improve the energy resolution for CZT detecting system. Digital multi-channel analyzer with rising time discriminator has significant advantage for CZT detecting system. Abstract  
        关键词：CZT detector;Charge sensitive amplifier;Nuclear signal chain;Rise time discrimination;Digital pulse amplitude analyzer   
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        发布时间：2021-03-03
      • DING Changji,MAO Benjiang,YUAN Yonggang,JIANG Zhigang,YANG Chaowen
        Vol. 38, Issue 11, Article number: 110402(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110402
        摘要：Background: Due to its imaging principle advantages and the development of detectors, nuclear electronics, Compton camera has once again put forward. Purpose: This study aims to build a Compton camera via Monte Carlo simulation and test its backprojection algorithm. Methods: By using Monte Carlo simulation software GEANT4, a Compton camera with stripes structure is designed and data for reconstruction image of source is read out. Backprojection imaging reconstruction algorithm is studied for getting the reconstruction of source. Results: Using backprojection algorithm and simulated Compton camera, when the distance between source and the scattering detector is 40 mm, the spatial resolution is FWHM=8.0 mm, angular resolution is 3° and γ photon imaging efficiency is 0.38%, which are better than most of the pinhole and coded aperture γ camera imaging. Conclusion: Because of the existence of large amount of data, Compton camera needs long calculation time for measuring data. The next step is improving simulated Compton camera to study its performance parameters, while the maximum likelihood algorithm could improve the spatial resolution of Compton camera. Abstract  
        关键词：Compton camera;Monte Carlo simulation;Backprojection imaging reconstruction algorithm   
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        发布时间：2021-03-03
      • CHEN Jun,LYU Bo,WANG Fudi,PAN Xiayun,LI Yingying,FU Jia,YIN Xianghui,HU Ruiji,FENG Shuangyuan,SHI Yuejiang,YU Yi,YE Minyou
        Vol. 38, Issue 11, Article number: 110403(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110403
        摘要：Background: X-ray curved-crystal spectrometer, as one of important diagnostic tool for measuring the plasma temperature and rotation velocity of the tokamak, is usually based on the satellite spectra of some special kind of impurity by single-crystal diffraction, which limits the temperature range to be measured simultaneously. Purpose: This study aims to effectively broaden the temperature range of the spectrometers, an assembly of double-crystal was designed to replace the previous of single-crystal. Methods: The two crystals of the assembly having the similar Bragg angles were installed on the same pedestal, which could make the spectra recorded on the same detector. Consideration and technology route of the double-crystal were described and analyzed together with the experimental tests on the Experimental Advanced Superconducting Tokamak (EAST). Results: Experimental results on the double-crystal X-ray spectrometer showed that the He-like and H-like Ar spectra were obtained for the first time, and the ion Ar temperatures calculated by two kinds of spectra were in good consistence within a certain error range. Conclusion: The application of double-crystal for X-ray curved-crystal spectrometers on EAST proposed in this paper is applicable and feasible. Abstract  
        关键词：Plasma diagnostic;Crystal spectrometers;Double crystal;Doppler broadening   
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        发布时间：2021-03-03
      • ZHAO Jiankun,GE Liangquan,ZHANG Qingxian,LU Zhenrui,LUO Yaoyao
        Vol. 38, Issue 11, Article number: 110501(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110501
        摘要：Background: With large differences in mass density, Basalt, KREEP and Dunite are representative and widely distributed on lunar surface. Cosmic-induced ?-ray is produced after energetic particles (Galactic Cosmic Rays, GCR; Solar Particle Event, SPE) impacting on lunabase rocks. Purpose: This study aims at discovering the factors of cosmic-induced ?-ray spectrum and then utilizing the gamma ray data for lunar exploration more efficiency. Methods: A Monte Carlo model for proton-induced gamma ray is designed for the FLUKA simulation software to research cosmic-induced gamma original spectrum. Data analysis is applied to find the relationship between the characteristic spectrum and the densities of lunabase rocks. Results: The model is appropriate to simulate cosmic-induced ?-ray original spectrum. A great variety of original spectrum characteristics, such as energies of main elements, positron annihilation peak and radiation balanced peak, are acquired. Conclusion: A positive correlation is found between mass density of lunabase rock and characteristic peak intensity. These researches for original spectrum can be applied to comparing different lunar gamma-ray spectrum and rock mass density mapping on lunar surface as a reference. Abstract  
        关键词：Lunabase;Cosmic-induced gamma field;Original spectrum;FLUKA   
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        发布时间：2021-03-03
      • XIE Mingliang,CHEN Yuqing,YU Lei,SHI Hao
        Vol. 38, Issue 11, Article number: 110502(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110502
        摘要：Background: NJOY is used widely nuclear data processing program that can convert the data format of ENDF/B nuclear database into WIMS format of the multi-group cross section database. Purpose: This study aims to produce a multi-group database of WIMS-D format on the basis of the latest release of nuclear evaluation library ENDF/B-VII.1 by using nuclear data processing program NJOY-99. Methods: In allusion to basic fuel cell homogenization calculation benchmark problem of the light water reactor (LWR), taking the 235U and 238U nuclide as the main objects of analysis, the effect on processing time of making cross section library, as well as integral parameters ΔKeff and data sensitivity of selecting input parameters of the NJOY program were compared and analyzed, which optimized the option of input parameter. Results and Conclusion: The results of validating on benchmark problems showed that the production of the multi-group database was correct, which embodied the high accuracy of calculation and provided the basis data of fuel assembly homogenization calculation for pressurized water reactor. Abstract  
        关键词：ENDF/B-VII.1;WIMS;NJOY-99;Nuclear data library   
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        发布时间：2021-03-03
      • WU Haosheng,MAO Shifeng,CHEN Bin,ZHANG Chuanjia,LUO Zhengping,GUO Yong,PENG Xuebing,YE Minyou
        Vol. 38, Issue 11, Article number: 110601(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110601
        摘要：Background: In the conceptual design of China Fusion Engineering Test Reactor (CFETR), two additional poloidal coils, with respect to International Thermonuclear Experimental Reactor (ITER), are used to generate snowflake divertor configuration proposed recently for the purpose of exploring effective way for reducing heat loads onto divertor targets. Heat flux onto divertor targets was dramatically reduced in detached regime, while the performance of impurity screening would also be reduced due to the decrease of divertor temperature. Purpose: This study aims to simulate the detachment operation of snowflake divertor for CFETR. Methods: The detachment operational status was investigated by numerical simulation based on the edge plasma simulation software SOLPS (Scrape-off Layer Plasma Simulation). A D2 gas puffing in the main chamber was used to change plasma density. Results: When the gas puffing rate was sufficiently high, snowflake divertor of CFETR was completely detached, and the ion flux and heat loads onto the targets significantly decreased. However, the plasma temperature in the divertor region was too low and the impurities could easily pass through the X-point to core plasma, which implied a risk of radiation instability. Conclusion: Therefore, a proper operational status for the snowflake divertor in CFETR should be partial detachment.Cited  
        关键词：CFETR;Snowflake divertor;Detachment;Scrape-off layer;Numerical simulation   
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        发布时间：2021-03-03
      • LI Kai,ZHONG Guoqiang,HU Liqun,LIU Guangzhu,ZHOU Ruijie,PU Neng
        Vol. 38, Issue 11, Article number: 110602(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110602
        摘要：Background: During the experiment of Experimental Advanced Superconducting Tokamak (EAST), reaction of D-D may generate neutrons with energy of 2.45 MeV, and bremsstrahlung gamma rays and neutron activated gamma rays as well. Purpose: The aim is to study the radiation of neutrons and gamma rays in the EAST hall during the running of EAST tokamak and obtain the radiation doses under different modes and parameters by implementing a radiation monitoring system to diagnose some plasma parameters and ensure the radiation safety of the personnel and the environment around EAST. Methods: In consideration of the highly and transient radiation doses of neutrons and gamma rays contrast to the lowly environmental background during the plasma discharge in the EAST hall, the combination of high ranging and fast responding detectors are adopted in the EAST hall whilst high sensitivity and stability detectors are deployed in the environment. Thirteen monitoring points were selected around the EAST, each point contains a neutron detector and a gamma ray detector. Combination of Ethernet and twisted pair are adopted for the data transmission, and the radiation monitoring software based on LabVIEW was developed. Results: A radiation monitoring system of EAST tokamak was successfully built to monitor and save the real-time radiation dose rates of each detector, and to produce an alarm signal when abnormal dose rate happens. The radiation monitoring system had run stably for more than three months during the EAST experiment in the spring of 2015, and obtained many useful experimental data on fusion radiation safety and protection. Conclusion: The radiation monitoring system can well monitor the radiation around the EAST tokamak, and provide a platform for the future study of radiation safety and protection of the fusion reactor. Abstract  
        关键词：EAST;Tokamak;Radiation monitoring;Neutron;Gamma ray   
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        发布时间：2021-03-03
      • HU Chundong,XU Yongjian
        Vol. 38, Issue 11, Article number: 110603(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.110603
        摘要：Background: As the first full superconducting non-circular cross section Tokomak in the world, Experimental Advanced Superconducting Tokamak (EAST) is used to explore the forefront physics and engineering issues on the construction of Tokomak fusion reactor. Neutral beam injection has been recognized as one of the most effective means for plasma heating. Purpose: This paper aims to present the latest progresses of EAST neutral beam injector. Methods: Long pulse beam extraction and high power beam extraction were experimentally tested to verify the performance of a set of neutral beam injectors (4–8 MW, 10–100 s) which were developed and put into operation in 2014. Results: Test results showed that beam power and pulse length met or exceeded the design requirments. Conclusion: All these progresses lay a solid foundation for the achievement of plasma heating and current drive for EAST in the future. Abstract  
        关键词：Neutral beam injector;Beam extraction;Ion source   
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