最新刊期
      卷 0 ， 期 0 ， 2020
      • XU Pengshou XIE Changkun SUN Yuming XU Faqiang DENG Rui PAN Haibin SHIChaoshu
        Issue 6, (2003)
        摘要：In this paper, we report the progress on energy band structure studies of wide-band-gap semiconductors in NSRL. The energy band structure of ZnO and its native point defects have been calculated by using FP-LMTO method for the first time. We confirmed theoretically that Zn is the main factor to induce the native n-type conductiv-ity in ZnO, which effects on the spectral properties of ZnO are also discussed. The energy band dispersion of both bulk and surface states on wurtzite GaN(0001) has been studied by using synchrotron radiation angle resolved photo-electron spectroscopy (SRARPES). A theoretical calculation of the atomic and electronic structure of β-SiC(110) surface is also presented by using FPLAPW method for the first time. The results show that the surface is char-acterized by a top-layer bond-length-contracting rotation relaxation and the surface relaxation induces the change from metallic to semiconducting characterization.  
        关键词：Wide-band-gap semiconductor;Energy band structure;Synchrotron radiation angle resolved photoelec-tron spectroscopy;Defect;Surface structure   
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        发布时间：2021-03-12
      • LI Chengxiang WANG Wei
        Issue 6, (2003)
        摘要：The edge radiation from the inlet and exit of a bending magnet was introduced. Then flux distribution and brightness characteristics of zero edge length, finite edge length and finite straight-section length were discussed in detail. After a comparison with ordinary infrared radiation in both flux and brightness, we conclude that the edge infrared radiation is a good infrared synchrotron source.  
        关键词：Infrared synchrotron radiation;Edge radiation;Edge length;Flux;Brightness   
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        发布时间：2021-03-12
      • YU Xiaojiang WANG Qiuping CHEN Qiang XU Pengshou
        Issue 6, (2003)
        摘要：The influence of two unparalleled axes of a variable included angle monochromator on wavelength tuning and resolution is discussed numerically in the text. And a method of measuring the unparallelism of two axes by using a paralleloscope and re-alignment of the axes is introduced.  
        关键词：Variable angle monochromator;Tolerance analysis;Paralleloscope;Parallelism measurement   
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        发布时间：2021-03-12
      • XIAO Haiqing ZHANG Zhiyong LI Fuliang CHAI Zhifang
        Issue 6, (2003)
        摘要：Concentrations of 8 REEs (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in fern and their host soil, collected from the south China, have been determined by INAA. The chondrite-normalized REE patterns for different plants and different parts of Dicranopteris dichotoma and their host soil were studied. The results showed that the older the leaves are, the higher the concentration levels of REE are. Particularly, leaves of the fern (Dicranopteris dichotoma) contained extremely high concentration of the total REE(332—3411 礸/g). Generally, the REE distribution pattern in each sort of plant was very similar and reflected the characteristics of their host soil. However, the chon-drite-normalized REE patterns in some plants relative to the host soils exhibited obvious fractionation, such as the de-pletion of the heavy REE in leaves of the fern species, Dicranopteris dichotoma.  
        关键词：Rare earth elements;Neutron activation analysis;Fern   
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        发布时间：2021-03-12
      • LI Mian1 LI Zhanbin1 DING Wenfeng2 1
        Issue 6, (2003)
        摘要：Based on the principle and method of rare earth elements (REE) tracer and NAA for the study of soil erosion, the changeable process of rill erosion on loess sloping surface was researched in runoff scouring experiments. The results showed that the REE tracer and NAA method can be used not only quantitatively to determine soil erosion amounts on different slope sections, but also to reveal the changeable trend of relative erosion amounts. The relative errors are mostly less than 20% for the tracing elements, which is considered satisfactory in the soil erosion studies.  
        关键词：NAA;Rill erosion process;REE tracer method   
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        发布时间：2021-03-12
      • WANG Wenmin1 Roth J2 Lindig S2 Wu C H2 1
        Issue 6, (2003)
        摘要：The surface damage of W and Mo due to D+ bombardment, especially the blister formation and D retention in the surface layer of W, was systematically studied by means of SEM and D depth-profiling. The bombardment energies are of 100—1000eV with the D+ fluence from 11019 cm-2 to 11021 cm-2. The target temperatures are adjusted at room temperature, 600C and 800 C, respectively, during the bombardment. Possible mechanisms are proposed to describe the observed phenomena.  
        关键词：Ion bombardment;D trapping;Blister formation;W;Mo   
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        发布时间：2021-03-12
      • WANG Rong1,3 ZHANG Xinhui4 GUO Zengliang4 ZHAI Zuoxu4 ZHU Shengyun5 1
        Issue 6, (2003)
          
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        发布时间：2021-03-12
      • ZHONG Zhengkun XING Pifeng WANG Changbin
        Issue 6, (2003)
        摘要：Cryogenic adsorption of hydrogen isotopes on porous adsorbents is an attractive method for tritium re-covery from helium which conducts as sweep gas of tritium breeding blanket in a fusion reactor. In order to use this method to extract tritium effectively, it is necessary to investigate adsorption properties of various candidate adsorb-ents. In this study isotherms and isotopic effects of hydrogen isotopes on three carbonaceous adsorbents: carbon mo-lecular sieve, activated carbon and carbon nano-fiber have been tested at liquid nitrogen temperature. It was con-cluded that the first two adsorbents could be used for this purpose and the third one was excluded because of its low adsorption capacity. Adsorbent modification using concentrated HNO3 and experimental results of the modified ad-sorbents have also been reported.  
        关键词：Cryogenic adsorption;Hydrogen isotopes;Isotherm;Isotopic effect;Adsorbent modification   
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        发布时间：2021-03-12
      • TENG Yanguo1 TUO Xianguo2,3 NI Shijun3 ZHANG Chengjiang3 CHENG Bo3 1
        Issue 6, (2003)
        摘要：A high sensitive EDXRF analyzer is made up with a double exciting apparatus including low energy X-ray tube and isotope source, and an electrically cooled Sin-PIN detector. The analyzer is characterized of high en-ergy resolution and low detection limit. Heavy metal contents in soil of the Panzhihua region were analyzed by the EDXRF analyzer. The results show that the contaminated soil was mainly distributed in the industrial and mining area.  
        关键词：EDXRF;Environmental pollution assessment;Heavy metal;Soil   
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        发布时间：2021-03-12
      • ZHOU Xinzhi ZHOU Yong ZHOU Youyi WANG Xurong
        Issue 6, (2003)
        摘要：This paper reports the energy deposition calculations of low-energy electrons in multi-layer media, such as wires and cables, and the calculations of the electron reflection correction coefficients by using the bipartition model of electron transport. With the calculation results of reflection coefficients for 0.2—10MeV electrons on Nylon, CIM, C, Al and Cu, along with an approximate formula for dose measurements and calculation, a set of absorbed dose monitoring and control system of EB radiation processing for wires and cables has been built, and its working mechanism and performance achieved are discussed.  
        关键词：Absorbed dose;Bipartition model;Radiation processing;Monitoring system   
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        发布时间：2021-03-12
      • HUANG Jianguo1,2 YANG Xuanzong1 ZHENG Shaobai1 FENG Chunhua1 ZHANG Houxian1 WANG Long1 1
        Issue 6, (2003)
        摘要：Multi-cycle AC operation was firstly carried out in CT-6B Tokamak, and plasmas in different cycles were compared. The results show that although there are differences in the plasma-wall interactions in the two halves of each AC cycle, the purity of plasma is not significantly affected. The distribution of plasma current density was measured by a set of internal magnetic probe system. It was found that the plasma current is firstly reversed on the low field side, and the local positive and negative currents coexist as the net current passes zero, in which case the particles are efficiently confined by the magnetic surfaces.  
        关键词：Tokamak;Alternating current operation;Reverses +   
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        发布时间：2021-03-12
      • WANG Jianping CHEN Tiemei
        Issue 6, (2003)
        摘要：Seventy-seven pottery and proto-porcelain sherds collected from Meihuadun, Yingang and Henglingshan sites of Boluo County, Guangdong Province were studied with INAA . These sherds are of Western Zhou to Warring States Period. Concentrations of 27 elements were measured, then principal component analysis and other statistical procedures were applied to the data set in order to classify these sherds. This study shows: (1) Though these 3 ar-chaeological sites are located close to each other within an area of about 1000 km2, ancient potters of these sites might use raw materials of different origins for pottery production, as pottery sherds of these 3 sites show different chemical compositions. Such differentiation is also observed for the proto-porcelain samples, indicating that proto-porcelain samples found at Meihuadun and Henglingshan might be of different provenance; (2) In each site during the Western Zhou to Spring- Autumn Period the same raw material was used for both hard pottery and soft pottery manufacturing, while during the Warring States Period no similarity in chemical compositions was observed between hard pottery and soft pottery samples. It is wondered if this phenomenon means an advancement of ceramic technology.  
          
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        发布时间：2021-03-12
      • CHEN Xiaowen1 BAI Xinde1 YU Renhong1 CHEN baoshan2 1
        Issue 6, (2003)
        摘要：In order to investigate the oxidation behavior of Zr-4 induced by Ce ion implantation at different fluences, mass gain curves of the different specimens including as-received Zr-4 and Ce ions-implanted Zr-4 were measured after oxidation in air at 500℃. It was obviously found that a significant improvement was achieved in the oxidation behavior of Ce ions-implanted Zr-4. The depth profile of the element composition was obtained by AES, and the va-lence of the oxides in the scale was analyzed by XPS. The phase transformation in the oxide films was examined by GAXRD showing that the addition of Ce had transformed the phase from monoclinic ZrO2 to hexagonal ZrO2. Finally, mechanism of the improvement of the oxidation behavior was discussed.  
        关键词：Zr-4;Oxidation behavior;Ce ion implantation;Phase transformation   
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        发布时间：2021-03-12
      • LUO Shunzhong1 ZHANG Taiming1 LIU Ning2 YANG Yuanyou2 JIN Jiannan2 HUA Xinfeng2 1
        Issue 6, (2003)
          
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        发布时间：2021-03-12
      • YANG Jiangrong ZOU Juesheng WANG Haifeng WANG Xiaohong WANG Jiayong
        Issue 6, (2003)
        摘要：The metallic uranium surface was treated with CO, and then its oxidation resistance in dry air at 40℃ and its electrochemical corrosion resistance in 14 mmol/L Cl- solution were studied by the weight gain method and the electrochemical measurement, respectively. The investigation indicates that both oxidation resistance in dry air at 40℃ and electrochemical corrosion resistance in the above solution are improved after the uranium surface is treated with CO. In addition, corrosion resistance of the treated uranium increases with raising of the CO dose in a certain range.  
        关键词：Metallic uranium;Carbon monoxide;Oxidation;Electrochemical corrosion   
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        发布时间：2021-03-12
      • XIAO Yonghou YANG Weifan YUAN Shuanggui XU Yanbing
        Issue 6, (2003)
        摘要：The experimental conditions for separation of Ra from Ba with cation exchange technique by using 133Ba, 224Ra and 212Pb as tracers, and 0.1 mol/L (NH4)2H2EDTA-0.3 mol/L NH4Ac solution as eluent are studied. A proce-dure suitable for separation of Ra from the ThO2 targets irradiated by 60 MeV/u 18O ions is developed. The results demon-strate that the decontamination effect for main reaction products, specially radioactive Ba isotopes, is satisfactory. The chemical yield of Ra is more than 70%.  
        关键词：Ra;Th;Cation exchange technique;g-ray spectrum   
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        发布时间：2021-03-12
      • TANG Lijun1,2 LU Songlin1 LI Deming1 1
        Issue 6, (2003)
        摘要：A DC—100kHz current transducer is developed using a new technique on zero-flux detecting principle. It was shown that the new current transducer is of high performance, its magnetic core need not be selected very strin-gently, and it is easy to manufacture.  
        关键词：Current transducer;Zero-flux;Zero-flux sensing   
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        发布时间：2021-03-12
      • SUN Shaohua GAO Wenhuan ZHANG Li CHEN Zhiqiang
        Issue 6, (2003)
        摘要：In the scanning process of the industrial computed tomography, if some detectors fail, there will be serious artifacts in the reconstructed image and such artifacts must be corrected. If we get data of the failing detectors by in-terpolation, then the fake data will be introduced. If we filter the reconstructed image only, the artifacts can not be eliminated completely. This paper proposes an approach based on Ordered Subsets Convex in conjunction with me-dian filter to correct the detector-failure-induced artifacts, and promising results are achieved in respect to the cor-recting time and the quality of reconstructed image.  
        关键词：Industrial computed tomography;Image reconstruction;Ordered Subsets Convex   
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        发布时间：2021-03-12
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