最新刊期
      卷 0 ， 期 0 ， 2020
      • Issue 6, (1999)
        摘要：The valence electron densities of bulk and microdefects in binary Fe3Al, and Fe3Al doped with Cr or Mo have been calculated by using the positron lifetime parameters of the alloys. The result indicates that, the 3d electrons in Fe atoms have well--localized properties and tend to form covalent bonds with the valence electrons in Al atoms, the bonding nature in Fe3Al is a mixture of metallic and covalent. The large--open--volume defects occur on grain boundary in Fe3Al and the bonding cohesion of the grain boundary is weak due to the low density of valence electron there. The addition of Mo into Fe3Al results in the decrease of the ordering energy of the alloy and the open--volume defects on grain boundary. Since the radius of Mo atom is larger than that of Fe atom, when Mo atoms substitute for Fe atoms, they will distort the lattice, enlarge the volume of the lattice and therefore decrease the density of valence electron in the bulk of the alloy. The addition of Cr into Fe3Al increases the densities of valence electrons in the bulk and the grain boundary, thusincreasing the metallic bonding cohesion. Cr is found to be a beneficial element in improving the brittleness of Fe3Al alloy.  
        关键词：Positron lifetimes;Fe3Al alloys;Defects;Density of valence electrons;Mechanical properties   
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        发布时间：2021-03-12
      • Issue 6, (1999)
        摘要：The preparation of Mg3129mTeO6 Mossbauer source is reported. Because of its high recoilless fraction and longer lifetime, the source is suitable for the measurement at room temperature.  
        关键词：Mossbauer source   
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        发布时间：2021-03-12
      • Issue 6, (1999)
        摘要：In this paper, electron beam physics, equilibrium of plasma in Tokamak under electron injection and physical problems involved in the electron injector were analytically studied. The result indicates that the electron beam will be stable when intensity of added electrical field is larger than that of beam’s electrical field. For maintaining the equilibrium of plasma in Tokamak it is better to set the intensity of added field as low as possible. The working temperature of cathode between 8001000K will meet the requirement for experiment on HT--6M Tokamak. By using some insulation measures the injector should be workable and safe under a voltage of 25kV.  
        关键词：Electron injection;Electrical drift;Tokamak   
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        发布时间：2021-03-12
      • Issue 6, (1999)
        摘要：The spin precssion introduced by the interactions between spin magnetic moment of A particle and magnetic field has been taken into account. A new method for dealing with the precession has been proposed and used to analyses the effect of spin precession on the polarization of A particle and modifys the A polarization. The new method has been used in experimental data analysis.  
        关键词：Interaction between magnetic moment and magnetic field;Spin precession;Modification of polarization   
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        发布时间：2021-03-12
      • Issue 6, (1999)
        摘要：The design, construction and characteristics of an electron cyclotron resonance (ECR) ion source are emphatically introduced. An optimized triple layer window (quartz, alumina and BN) was found to be very effective in order to achieving a long lifetime, high--density plasma as well as high quantity introducing microwave. The axial magnetic field to satisfy the ECR condition (87.5mT) and to provide plasma confinement was produced by two solenoid coils with iron yokes. Three C:N films were prepared by decomposing CH4--NH3 in this source. After the films were annealed in vacuum, two of them were rent in C:N cluster fiber with different diameters.  
        关键词：ECR ion source;Microwave introduction window;Magnetic;C:N cluster fiber   
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        发布时间：2021-03-12
      • Issue 6, (1999)
        摘要：The atomic and nuclear interactions of a beam of deuterium cluster ions (d3+) with solid have been studied. The experimental results are found to be different from the results of interaction of isolated deuterons with solid. The interaction mechanism of cluster ions and solid is discussed.  
        关键词：Deuterium cluster ion;Atomic and nuclear cluster effect;Exciting of shell electron;D--D fusion   
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        发布时间：2021-03-12
      • CHEN Shengfu
        Issue 6, (1999)
        摘要：We found (3-aminopropyl)-triethanoxysil (APS)-mica is an ideal kind of substrate for microtuble and is easily prepared. This method could be very useful in investigating microtubules properties and dynamic processes under near--nature environment.  
        关键词：Atomic Force Microscope;Substrate;Microtuble;APS-mica   
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        发布时间：2021-03-12
      • Issue 6, (1999)
        摘要：The abundance variations of iridium and other related elements in the peat samples from a drilling hole of the Tunguska explosion epicenter were studied by neutron activation analysis. We found the striking anomaly of iridium abundance at the 1908 explosion layer and its overlying strata, whose maximum reaches over five times higher than the background value. On the basis of the elemental correlation of Ir with Ni and Co and in combination with the information of hydrogen and carbonisotopic excursions, a hypothesis that a comet entering the earth orbit might causethis modern explosion event was deduced.  
        关键词：Neutron activation;Iridium;Tunguska explosion;Comet   
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        发布时间：2021-03-12
      • Issue 6, (1999)
        摘要：Neutron Activation Analysis method was used to measure the atmosphere andwater samples from Chengdu area. The distribution feature of harmful elements was studied according to the analysis results.  
        关键词：Neutron activation analysis;Atmosphere environment;Hydrology environment   
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        <引用本文> <批量引用> 7201494 false
        发布时间：2021-03-12
      • Issue 6, (1999)
        摘要：A bovine liver candidate reference material specially for micro--analytical techniques is prepared. The laser particle size test shows that the median particle’s diameter is 22 μ m and the size corresponding to the largest peak in the distributions is about 35 μm. For reasons of quality control and better assessment of resulting data, its certification campaigns on world--wide basis will be organized by IAEA.  
        关键词：Standard reference material;Bovine liver;Analysis quality control   
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        发布时间：2021-03-12
      • Issue 6, (1999)
        摘要：The structure and electrical calibration principle of a silicon absorbed dose calorimeter are described. Specific--heat capacity of silicon as the electrical calibration factor of the calorimeter at different temperature ranging from ooC to 35℃ is given. Its error is also discussed.  
        关键词：Silicon calorimeter;Electrical calibration factor   
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        发布时间：2021-03-12
      • Issue 6, (1999)
        摘要：The development of a new potential bone pain palliation agent, 188Re--HEDP,was described here. The ligand HEDP was synthesized giving a yield over 90% and the is8Re--HEDP was prepared with generator--produced 188Re. Labelling yield and radiochemical purity were determined by TLC and HPLC. The optimal labelling conditions were systematically investigated and the kit formulation was developed.The labelling efficiency of 188Re--HEDP was greater than 95%, and the radiochemicalpurity was still over 90% after stored at 15℃ for 12 hrs.  
        关键词：188Re;HEDP;Chemical synthesis;Labelling   
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        发布时间：2021-03-12
      • Issue 6, (1999)
        摘要：The influence factors on the life period of nuclear safety--related equipments (semiconductor electornic, electromachine, mechanical parts and devices) used in nuclear power plant are discussed. The failure mode and failure mechanism of the equipments are analyzed. The theory and method of simulation acceleration test of life period for those equipments are introduced. The application of gray prediction of acceleration life test is studied.  
        关键词：Nuclear safety related equipment;Life period;Acceleration life test;Gray prediction;Failure mode and failure mechanism analysis   
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        发布时间：2021-03-12
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