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      • Chengde Shen,Weixi Yi,Lianfan Liu,Weinan Zhou
        Vol. 11, Issue 7, (1988)
        摘要：For ten years the accelcrator mass spectrometry of 14C and 10Be has been developing rapidly. It has been proved to be a successful new experimental method. It has attracted scholars with interests ranging from the time variation of cosmic rays to the evolution of soils. 10Be has a high atmospheric production rate and a low abundance of the stable isotope. The measurement of 10Be in the environment has been applied to research on the atmosphere, the cosmic-ray history found in Arctic ice, pelagic scdiments, the evolution of loess and its erosion, the formation of continental margins and the nature of island arc volcanism. A brief review is given in this paper.  
        关键词：accelerator mass spectrometry;gcoscience   
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        发布时间：2022-08-16
      • Zewu Yao,Kangsen Du,Fugen Chen,Zhili Wu,Dong Cai,Hailin Hou
        Vol. 11, Issue 7, (1988)
        摘要：In the paper, the dose field of the irradiator was calculated. The total dose at any point in the product was treated as a combination of the static dose and the dynamic dose. Dmax, Dmln, dose uniformity, utilization efficiency of the irradiator and output of irradiated products were measured, and the measured values were compared with the calculated values.  
        关键词：capacity of irradiator;utilization efficiency of irradiator;dose uniformity   
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        发布时间：2022-08-16
      • Ting Lu
        Vol. 11, Issue 7, (1988)
        摘要：The resolution of a positron lifetime spectrometer is mainly dependent on selection of the energy window. A method to obtain the optimum resolution is described in this paper. The workable region for a spectrometer was divided into 42 small regions. The resolution(FWHM), the count rate and the peak walk were measured for every small region. From among them, the good regions with high count rate, narrow FWHM and small peak walk were selected. Several such good regions were selected to form the energy window. The experimental values for the resolution were found to be coincident with the theoretical values very well.  
        关键词：Positron annihilation;lifetime spectrometer;Resolution   
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        发布时间：2022-08-16
      • Shujuan Zhang,Zhenghua Wang,Fusheng Sun,Hailun Shen,Hengde Li
        Vol. 11, Issue 7, (1988)
        摘要：This paper describes the advantages and the configuration of N type HPGe detector. The manufacturing technology and performance of a closed N type HPGe coaxial detector with boron implanted is reported. With a sensitive volume of 88 cm3, the detector has a relative efficiency of about 19%. The energy resolution at 1.33 MeV γ-ray is 2.6 keV and the ratio of peak to Compton is 34.  
        关键词：high purity germanium(HPGe);coaxial detector;depletion voltage;energy resolution   
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        发布时间：2022-08-16
      • Jiaju Zhang,Hao Tang,Wenjin Deng,Jianming Hu
        Vol. 11, Issue 7, (1988)
        摘要：Based on the interaction between γ-photon and the matter, an 125I single-photon analyser for measuring mineral content of radius in vivo was designed. The principle, basic structure and characteristics for the analyser were described. Data processing, curve calibration, error analysis and preliminary clinic application were also presented. This instrument has good linearity and reproducibility, and a precision of ±5%. It is reliable, easy to operate, quick to measure and able to be quantitative. Being non-traumatic, the instrument can be extented to medical science as well as clinic applications.  
        关键词：Krywords: 125I;absorptiometry;bone mineral content   
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        发布时间：2022-08-16
      • Hanpeng Liu,Wenxun Wang
        Vol. 11, Issue 7, (1988)
        摘要：The principles and advantages of measuring lifetime of atomic and molecular excited states using the beam-foil method are described. The experimental procedure and results are given. Three possible sources of error in our experiment are discussed.  
        关键词：excited-state lifetime;beam-foil method;cascade;collision relaxation   
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        发布时间：2022-08-16
      • Zhongning Wang,Liang Tao
        Vol. 11, Issue 7, (1988)
        摘要：Generally, the isotope abundance of a compound labelled with stable isotopes can be calculated using Biemann's method. But there are some proton adducts mixed with the fragments of mass spectra, which make the error increase when calculating the isotope abundance, In order to decrease this error, we have developed the data analysis method of mass spectra to the molecules labelled with up to 4, 5, 6 or 7 deuterium atoms respectively. This method will eliminate the error caused by proton adducts and is very useful in the determination of compounds labelled with stable isotopes, especially amino acids. labelled with 2H. A program is made by means of the Newton iteration method.  
        关键词：Mass spectra;proton adduct;Isotope abundance   
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        发布时间：2022-08-16
      • Zhufang Gong,Jun Hu,Zuhe Bian,Rongdian Han,Zhaomin Wang,Zitai Song
        Vol. 11, Issue 7, (1988)
        摘要：We have studied the afterglow, transmission and light-excited fluorescence spectra of BaF2 crystals before and after being irradiated. The results show that BaF2 has strong afterglow near 310 nm and 650 nm after being irradiated with 137Cs and 60Co γ-rays. The transmission of BaF2 crystals decreases after being irradiated, and its recovery is quite slow but becomes fast when BaF2 is irradiated with ultraviolet. The light of 290 nm can excite the slow component of the fluorescence of BaF2.  
        关键词：afterglow;Transmission;light-excited   
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        发布时间：2022-08-16
      • Minkang Teng,Ling Chen
        Vol. 11, Issue 7, (1988)
        摘要：Using computer programs, the data obtained by a data acquisition system are fitted. The fit parameters are changed and the best fit values can be found to calibrate the system, thus resulting in the calibrated values with a minimum systematic error.  
        关键词：system parameters;Positron annihilation;nonlinear programming;best solution;Fit;Calibration   
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        发布时间：2022-08-16
      • Zhiqiang Wu
        Vol. 11, Issue 7, (1988)
        摘要：A reversed-phase partition chromatography for separating technetium and ruthenium was described. Separation of fission product 99Tc from simulating high-level radioactive liquid wastes with quaternary ammonium 7402 was realized. The method for technetium was very selective, and for ruthenium its decontamination power was high. The experimental results indicated that the 99Tc recovery rate was 98%, and the 103Ru decontamination factor was 1×103.  
        关键词：technetium;Ruthenium;distribution;Decontamination factor;simulating liquid   
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        发布时间：2022-08-16
      • Mingde Shi,Ruxie Gao
        Vol. 11, Issue 7, (1988)
        摘要：Two kinds of 5ml vials made of glass or plastic were used in liquid scintillation counting. Our experiments showed that the amount of tritium in scintillation solution with small volume could be accurately measured. This method was economic and could greatly reduce radioactive contamination by decreasing the volume of scintillator solution  
        关键词：liquid scintillation;minivial   
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        发布时间：2022-08-16
      • Jinxing Chen,Pingqing Zhang
        Vol. 11, Issue 7, (1988)
        摘要：The horizontal distribution of β radioactivities in the sediments in the central South China Sea was determined. The results showed that moving direction of the sediments and bottom water at 13°30′N was from 113°E to 118°E and the movable superficial sediments seemed to have a thickness of more than 60cm.  
        关键词：total β radioactivities;horizontal distribution;Sediments;bottom water   
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        发布时间：2022-08-16
      • Shaofeng Ding,Zhaoxing Meng,Yongsheng Liu,Decun Shen
        Vol. 11, Issue 7, (1988)
        摘要：A low tritium pressure gas-liquid exchange technique for labelling organic molecules has been described. Experimental details on the potent narcotic analgesics with specific activities of 51.8—242.0 GBq/mmol are particularly presented. The advantages of the method over the high pressure method are also discussed.  
        关键词：low pressure tritium;gas-liquid exchange method;Tritium labelling   
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        发布时间：2022-08-16
      • Hanfang Li,Jianguo Zhang,Zhaoyi Bao,Zhixing Song,Wenrong Hu,Yong Zhang
        Vol. 11, Issue 7, (1988)
        摘要：Information on the contents of trace elements in hair from 144 male children is given. The contents of Ca, Mn, Fe, Cu, Zn and Pb were measured by XRF. It was found that the contents of Fe, Cu, Zn in hair from MBD patients were remarkably lower than normal. These changes have an influence on the nervous system. Multi-discriminant analysis results showed that some correlations exist between every trace element.  
        关键词：MBD;Hair;trace elemcnt   
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        发布时间：2022-08-16
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