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      卷 0 ， 期 0 ， 2020
      • Mingqian Wang,Lizhen Zheng,Yuxiong Li,Xiejin Yin,Huaixian Zhang,Huijun Liu,Zhengqing Liu
        Vol. 13, Issue 4, (1990)
        摘要：This paper is about the study of X-ray dose profile produced by HT-6M Tokamak when in operation. The measurement shows that X-rays have a continuum spectrum covering a rather wide energy range, and the intensities vary with places and directions. The dose on the vacuum vessel is larger and ranges from 2.3×102 mSv to 1.6×104 mSv, while the dose outside of the hall two meters from the torus surface is 0—1.8×102mSv. The number of photons with energy below 500 keV is about 85 percent of the total. The data given here provides necessary information of protection and safety estimation for normal operation of a device.  
        关键词：X-ray;Plasma density;Thermoluminescent dosemeter;Dose;Energy spectrum   
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        发布时间：2022-09-13
      • Meizhen Wu,Huangen Shou,Shufen Wang,Mingdong Hou,Yunfan Jin
        Vol. 13, Issue 4, (1990)
        摘要：Ion beam mixing in thin bilayered samples of Ti:Al by 100 keV argon ions at low temperature has been studied. The samples were prepared by sequential e-beam evaporation of about 500 nm of aluminium and a layer of titanium with different thickness onto single craystals of Si .The samples were bombarded with ion doses ranging from 1.2×1016 to 1.4×1017 ions/cm2 and analysed by RBS using a 2 MeV 4He beam. It is discovered that the mixing has caused broadening of the aluminium front edge and the titanium back edge in the RBS spectrum and the interfacial broadening increases clearly with ion doses. The mixing broadening of the Ti:Al interface has a square-root dependence on argon fluence; under the same bombardment conditions the square of mixing broadening is related to the thickness of the Ti layer. It is found that mixing is influenced by the presence of the interfacial oxide layer between the titanium and aluminium layers. The experimental results are compared with Monte Carlo computer simulations and the mixing process is discussed in delail.  
        关键词：Ion beam mixing;Broadening value of atomic mixing;Cascade collision Interstitial diffusion;Energy deposit;Profile due to nuclear stopping   
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        发布时间：2022-09-13
      • Zuguo Ding,Zhifang Chai,Jiamo Fu,Guoying Sheng,Qing Lin,Di Wu
        Vol. 13, Issue 4, (1990)
        摘要：Solvent extraction, column chromatography and instrumental neutron activation analysis (INAA) have been used to investigate the trace elements in crude oil, organic matter extracted from rocks and their related fractions. With these methods, about 70 crude oil samples from eight different oil fields in China and 6 extracted asphaltene samples of the lower paleozoic from the upper Yangtze region have been analyzed, and about 40 elements of interest have been determined. Those elements include Al, As, Au, Ba, Br, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, Ir, Mg, Mn, Mo, Na, Ni, Rb, Re, S, Sb, Sc, Se, Sr, Th, Zn, V and parts of REE. The experimental results show that the method possesses several advantages, i.e.non-destructive, multi-elements, sensitive, precise and accurate. Without ashing samples, the loss of volatile elements such as Cl, S, Se and Sb are avoided. The column chromatography makes it possible to study the distributions of trace elements in different fractions of crude oil and organic matter extracted. Meanwhile, the characters of trace elements in them have also been discussed in this paper.  
        关键词：INAA;Crude oil and organic matter extracted;Trace elements   
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        发布时间：2022-09-13
      • Xiaoyu Duan,Yonghua Wu,Li Ding
        Vol. 13, Issue 4, (1990)
        摘要：In this paper, the Monte Carlo method is used to simulate the gamma-ray scattering Mössbauer spectrum(GSMS). By assuming a plane geometry model, the GSMS of the samples of stainlees steel covered by a iron layer with various thickness are calculated using the method of statistics estimate. The results are coincident with experimental results. This means that the Monte Carlo method can be used to simulate the GSMS and to obtain the information of the thickness of the layer by comparing the areas of subspectra.  
        关键词：Monte Carlo method;Mossbauer spectra   
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        发布时间：2022-09-13
      • Meifen Huang
        Vol. 13, Issue 4, (1990)
        摘要：The principle method and apparatus for measuring ash content in paper are described. The method is based on the selective absorption of characteristic X-rays emitted by a radioisotope source as they pass through the paper. The measuring time for each sample is 30 seconds. The error comparing with the conventional weight method is less than ±1% and the standard deviation is±0.58% when the thickness of paper varies in the range from 28 g/m2 to 120 g/m2.  
        关键词：Ash content;Non-destructive measurement;X-ray preferential absorption;Fluorescent X-ray analysis   
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        发布时间：2022-09-13
      • Lianxue Gu,Anquan Le,Yingmei Gu,Jinxin Lin
        Vol. 13, Issue 4, (1990)
        摘要：By analyzing the spectrum shapes related to the instrumental condition, an optimized instrumental condition of the X-ray fluorescence analyzer is proposed in present paper, so as to improve the long-term measuring precision of the analyzer.  
        关键词：X-ray fluorescence spectrum;Precision;Threshold value;Channel width   
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        发布时间：2022-09-13
      • Jingxiu Li,Ying Yao,Aoling Guo,Runhua Zhang,Huanzhang Shi,Yingpu Xu
        Vol. 13, Issue 4, (1990)
        摘要：A magnetic analyzer and a plastic scintillation detector were used to measure electron beam energy spectrum of the 30 MeV electron linac. It was found that the energy spread of the electron beam was nearly 15%.  
        关键词：Electron beam energy spectrum measurement;Magnetic analyzer;Plastic scintillator detector;Extracted electron beam   
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        发布时间：2022-09-13
      • Weisheng Li,Wenxin Li,Tongyu Sun,Lili Zhao
        Vol. 13, Issue 4, (1990)
        摘要：An optimization method has been used to fit a 4-parameter expression +a3exp(-a4E) to the experimental efficiencies from coaxial Ge (Li) and HpGe detectors in the energy range of 122—1400 keV. Calculation approach to initial values of the parameters is given. A good fit is obtained, with the mean deviation between the experimental and fitted values being<2.0%.  
        关键词：Ge (Li) and HpGe detectors;Fit to efficiency curve;Optimization   
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        发布时间：2022-09-13
      • Qingsheng Liang,Biqin Cai
        Vol. 13, Issue 4, (1990)
        摘要：The feasibility and features of 14C dating by liquid scintillation technology for small samples are discussed in this paper. The adopting of small vacuum system and vanadium catalyzer enables the coefficient of recovery of synthesized benzene with 0.5 grams of carbon to reach about 80%. The lowest limit of measurement is about 40000 years. The advantages of this method are to safe time, effort, material and so on. Especially, this method is suitable to measure the ages of small samples of fine stratification of geological well log, subterranean water and ice core etc. This will push the study on fine change of paleoclimate and paleoenvironment since the later pleistocene forward. With this method we have determined ages of 8 samples which ages are four. The results are quite satisfactory.  
        关键词：Liquid scintillation technology for samall samples;Vanadium catalyzer;Liquid scintillater   
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        发布时间：2022-09-13
      • Lianfang Zhu,Mingdeng Fu,Xiebeng Chen,Xiaying Gao,Zhenyi Meng
        Vol. 13, Issue 4, (1990)
        摘要：Development and evaluation of standard radiation fields of 238Pu-Be neutron source and 60Co, 137Cs, 226Ra gamma sources for calibration of dosimeters were described in this report. The dose uncertainties determined by department of ionization radiation of Institute of Metrological Science of China are less than±2% for neutron field, ±5%for 60Co and 137Cs, ±5.3% for 226Ra.  
        关键词：Standard radiation fields;Calibration;Determination   
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        发布时间：2022-09-13
      • Huifang Ma,Zhenguo Yang
        Vol. 13, Issue 4, (1990)
        摘要：The technique of α-hydrohyisobutyric acid concentration gradient elution and pressurized ion exchange chromatography was described for the rapid separation of rare earth elements (La, Ce, Pr, Nd, Sm, Eu, and Y) in 12C-induced fission of 238U at the room temperoture (≥20℃) and the pressure of about 6×105 Pa/cm2. The yields of 7 fission products were determined.  
        关键词：Rare earth elements;Separation fission fragments;Mass distribution   
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        发布时间：2022-09-13
      • Yongyi Zhu,Jingjian Chen
        Vol. 13, Issue 4, (1990)
        摘要：140La and 141Ce tracer techniques have been applied to determine the dynamic process of absorption by crop after foliar spraying of La and Ce. After 48 hours of 140La and 141Ce solution spraying on leaves, the absorption of 140La and 141Ce by spring wheat got the peak value. At the fifth day it reached dynamic equilibrium, the absorption rate reached maxium on one hour after foliar spraying. The relationship of absorption rate of La and Ce with time can be described by the formula y=abx,Within six days, the absorption rate of La and Ce changed in the range of 0.18-1.549% and 0.38-0.87%, respectively, but the accumulation in grain was poor. The experimental results showed that the absorption of Ce by spring wheat from soil was more difficult than from leaves.  
        关键词：Spring wheat absorption;rare earth element;Isotope tracer;140La;141Ca   
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        发布时间：2022-09-13
      • Bingchai Zhu,Jiaben Lü,Congwu Wang,Tiehe Chen
        Vol. 13, Issue 4, (1990)
        摘要：In this paper, influence of chronic γ-ray radiation on chromosome aberration, micronucleus and transformation frequency in peripheral blood lymphocytes in rabbits induced by acute radiation was described. The result indicated that after rabbits were irradiated continuously by γ-ray at 0.26 mGy/min (0.05Gy/d) for 20 days (accumulation dose 1.0Gy), and immediatly acutely irradiated to 2.0 Gy (at 0.25Gy/min), the chromosome aberration frequency and micronucleus frequency in peripheral blood lymphocytes significantly decreased and lymphocyte transformation frequency significantly increased in comparison with acute radiation control group.  
        关键词：Chronic γ-ray radiation;Acure radiation;Chromosome aberration;Micronucleus;lymphocyte transformation   
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        发布时间：2022-09-13
      • Jialin Feng,Songsheng Shao,Hongzhen Liu,Meijun Zou,Yaping Lin
        Vol. 13, Issue 4, (1990)
        摘要：The peripheral blood lymphocyte chromosome was examined after 2.5h, in a case of 60Co exposure accident. The frequency of dicentric plus ring was 89%, thus radiation dose of 4.78 (4.53—4.88) Gy was estimated. The examinations of lymphocyte chromosome aberration within following 6 years showed that the incidence of dicentric plus ring decreased quickly and fluctuated at low level after the 3rd year post exposure, while the number of cells with stable aberrations remained practically unchanged and showing a tendency to increase. It is suggested that for estimative dose after exposure the Dic+R predominant, but in case of studying the late effect the stable aberrations was indispensable.  
        关键词：Chromosome;Dicentric plus ring;Stable aberration   
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        发布时间：2022-09-13
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