最新刊期
      卷 0 ， 期 0 ， 2020
      • Issue 3, (1996)
        摘要：In order to realize site-chosen mutation, the technique of free radical probe i.e.the method of determining Bragg peak location of heavy ion beam in wheat seeds using ESR spectroscopy, has been put forward in the paper. It is shown that Bragg peak of 21MeV/u 14N7+ ion beam is located in wheat embryos with an implanted depth of less than 1.0±0.2mm while 48MeVlu 14N7+ ion beam can penetrate the whole wheat seed, and hence the latter can not be used for site-chosen mutation.  
        关键词：Heavy ion beam;Bragg peak;Wheat;ESR spectroscopy;Free radical probe   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：A quantitative analysis method of the trace elements in biological specimens using the synchrotron radiation microprobe is described. The synchrotron radiation X-ray fluorescence microprobe system is calibrated by the standard sample specially prepared for the microprobe analysis. The mass thickness of each measured point is determined by measuring Compton scattering intensity in 17-20keV from the sample. In this way, concentration of the trace elements in samples can be measured correctly. The measured values of the biological standard reference material NBS-SRM-1577a are in good agreement with the certified values. The longitudinal concentration variations of some trace element in a single hair of pregnant women have been measured by this method.  
        关键词：Synchrotron radiation microprobe;Quantitative analysis;Trace element;Biological specimen   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：With the cell sample preparation method established for soft X-ray contact microscopy （SXCM） and a kind of fine focusing soft X-ray source, a high quality SXCM microimage of cultured Hep-2 tumor cells has been obtained with a resolution better than 28nm.  
        关键词：Soft X-ray contact microscopy;X-ray source;Sample preparation;Tumor cell;Resolution   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：A digital spectrum stabilization technique with four energy-windows has been generally used in the modern computerized nuclear logging instruments. The algorithm program applied in this technique is presented. A rather integrated real-time control flow of spectrum stabilization and its implementation by program have been put forward, and verified finely in the gamma-ray logging system. The distinctive advantages of the four energy-windows spectrum- stabiltiation technique,such as fast speed for identifying peak, high precision and strong anti-interference ability over the two energy-windows one have been discussed.  
        关键词：Adaptive digital filtering;Spectrum stabilisation;Nuclear logging;Proportional- Integral-Differential algorithm   
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        发布时间：2021-04-09
      • Yang Ruiying
        Issue 3, (1996)
        摘要：The concentrations of more than 20 elements in the glassy meteorites from Hainan Island, China have been measured by INAA. Precision and accuracy of the INAA method have been evaluated by using USGS and Chinese standard reference materials （GSR）, indicating that relative standard deviations for most element are less than 5%. A comparative study on the REE patterns and other trace elements shows that the geochemical characteristics of the glassy meteorites from Hainan Island are close to those of the Chinese continental sediment and the North America shale, implying that their parent rock is younger sediment.  
        关键词：Instrumental neutron activation analysis;Glassy meteorite;Sediment;Parent rock   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：The positron annihilation lifetime spectra of the under-aged and peak-aged Al-Li-Cu-Mg-Zr alloys were measured in the range from cryogenic to room temperature. The positron annihilation lifetime spectra show that the defect behaviours between two samples in the whole process of temperature rising are similar, but amount of the recovered vacancies is much greater in the peak-aged sample than in the under-aged one, and the average open space of defects in the peak-aged one is larger. With the particle δ’（Al3Li） growing in aging, the bulk election density in the alloy is increased and the strength enhanced.  
        关键词：Positron lifetime spectra;Al-Li-Cu-Mg-Zr alloy;Cryogenic temperature;Defects;Bulk electron density   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：The energy-distributions of ions of 30 and 200 keV N+ and 110 keV Fe+ ions through cell models have been calculated with the Monte Carlo method. Energy depositions produced by both electrons and molecular vibration were also discussed.The calculations show that the thermal energy deposition is concentrated in a thin layer, for the implantation of 30 keV N+ ions with a dose of 1× 1015/cm2, an energy density of up to 2.55 ×105J/cm3 can be reached within a depth of less than 200nm.  
        关键词：Low-energy heavy ion;Cascade ion;Cell model;Energy deposition distributions   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：(Ce4+) values of the eerie-cerous system have been measure and the experimental procedure is described in this paper. Both routine titration method and electrochemical measurement were used. Some interference factors, such as ultraviolet, acidity and temperature, were studied as well. The temperature coefficient of εm（Ce4+ ） value in this experiment is about -0.1%℃ -1. A statistic analysis was made for 24 experimental values of εm（Ce4+ ） and a Gaussian distribution was found. Ultimately, an average molar extinction coefficient of 553.2 ±1.3m2·mol-1 was obtained at ￣ 320nm in 0.4 mol/L H2SO4 system, with a relative standard deviation of 0.24% （95% confidence level） and a total uncertainty of 1.5%.  
        关键词：Dosimetry;Molar extinction coefficient εm;Ce￣（4+）-Ce￣（3+） dosimetric system   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：Recent work on the XRF system with X-ray lens is reported. A lens consisting of polycapillaries with an coter diameter of 200 μm can focus a divergent X-ray beam on a spot of 250μm diameter. The spectral characteristics of the lens has been measured,experimentally. The detection limit for some element can be improved by using a lens with specific spectral characteristic. A comparative study shows that the sensitivities for the middle-heavy elements using the XRF system with X-ray lens is 10 times higher than those using the OMICRON microfluorescence analyzer without X-ray lens.  
        关键词：X-rays;Microbeam X-ray fluorescence analysis;X-ray lens   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：The principle of determining the atomized concentrstion by β-ray tyansndssion measurement is described. The laboratory calibration was carried out with the wet filter paper to simulate wster content in the air, from which the quantitative relation between the β-ray count rate and water content in the air was derived. Therefore,the atomized concentration can be determined by using the β-ray count rate measured in situ and the calibration curve. The tests in still show that the β-ray transmission method used to measure the atomized concentration during the period of flood discharge from the high dam in hydropower stations is precise, rapid and has a higher sensitivity than the γ-ray transmission method.  
        关键词：tomized concentration during flood discharge;β-ray tyasmission;￣（90）Sr plane source   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：The elemental concentrations of Ca, Fe, Sr and As in some ancient vertebrate fossils have been measured by the XRF method. Different causes of fossils formation are explained. Existence of some poisonous elements in the fossils is discussed.  
        关键词：Animal fossil;XRF method;Elemental concentration;Cause of fossil formation   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：The distribution, disappearance and residue of carbofuran labelled with 14C in a simulated fish/duckweed aquatic ecosystem have been studied. The results show that the carbofuran content in water decreases with take because of being absorbed by sludge of riverbed, eaten by fish and hydrolysis. The residual carbefuran in fish tissues is higher than that in water because of enrichment. There is much difference among carbofuran contents in various fish tissues, and the order in each tissue is found to be viscera > bone > muscle > gill > skin.  
        关键词：Carbofuran;Pesticide residues;Fish   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：The behaviors of sorption and migration of 137Cs on granites at Shiliuyu and Yangfang have been investigated by the batch technique and the column experiment.The sorption ratios m and sorption equilibrium time are determined. The effects of granite particle size, solid-to-liquid ratio, pH value of simulated groundwater, and Cs concentration on the Cs sorption ratio are studied. The migration of Cs in granite column are investigsted, and the distribution coefficient KD is determined. The results show that the ability of granites at Shihuyu and Yangfang to adsorb Cs is rather weak. Therafore high efficient backfill materials for Cs are necessary if depository is built on the base of granite.  
        关键词：Nuclide migration;Granite;￣（137）Cs;Sorption ratio;Column distribution coefficient   
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        发布时间：2021-04-09
      • Issue 3, (1996)
        摘要：The forward displacement of atoms in the model cell due to cascade collisions induced by the bombardment of 30keV N+ ions is investigated with the Monte Carlo method. It is shown that the forward displacement is only 0.34μm when 1×1017ions/cm2 are implanted, suggesting that the forward displacement would not seem to cause the plant mutation. The mutation is probably induced by the X-rap produced by the low energy heavy ion projectiles.  
          
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        发布时间：2021-04-09
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