最新刊期
      卷 0 ， 期 0 ， 2020
      • Jiao Gulyue
        Issue 12, (1994)
        摘要：A three-dimensional ring probe has been adopted for scanning ion beam.It can monitor the intensity and position for two profiles and also predict the focusing gradients near the profiles and the movement of beam waist through the parameter companson.  
        关键词：Beam profile monitor;Beam radius;Half- width of beam waveform;Scanner;Converter   
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        发布时间：2021-04-09
      • Peng Yuqing
        Issue 12, (1994)
        摘要：This paper reviews the main structural characteristics and excellent physical properties of nanocrystalline materials and C60,some studies by positron annihilation on interfacial structure,therrnal stability and pressure effect of nanocrystalline materials and the positron lifetimes of C60.The significance of these studies and some questions are also pointed out.  
        关键词：Nanocrystalline materials;C60;Positron annihilation   
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        发布时间：2021-04-09
      • Issue 12, (1994)
        摘要：An assessment of the environmental environmental radioactive level in fly ash released from coal fired power plants was carried out.The contents of natural radionuclides 238U232Th226Ra,210Po and 210Pb in coal,bottom ash and fly ash samples were determined. Radionuclides were concentrated in the stack fly ash with a concentration factor of 1.4-17.2 in China.The radioactive emission levels from coal fired power plants were compared with those from nuclear power plants.  
        关键词：Coal fired power plants;Natural radioactive levels   
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        发布时间：2021-04-09
      • Issue 12, (1994)
        摘要：Based on the thermal hysteresis effect of heating Process,the I-V characteristics of liquid medal ion sources at different temperatures, the relationships between threshold voltage and endtter’s temperature and those between the slope of I（μA）-V（kV） curve and the temperature are measured respectively.The expert mental results are discussed.  
        关键词：Liquid medal;Ion source;Temperature   
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        发布时间：2021-04-09
      • Yu Caiqin
        Issue 12, (1994)
        摘要：The self- absorption correction factors for 241Am cylindrical volume sources were detemined.Theoretical calculations based on two calculation methods for self-absorption correction have been compared with the experimental values and the results discussed.  
        关键词：?241)Am;Volume source;Self-absorptin correction factors;Correction methods   
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        <引用本文> <批量引用> 8408198 false
        发布时间：2021-04-09
      • Issue 12, (1994)
        摘要：Positron lifetime measturements at room temperature have been performed for fullerite of C60/C70,C60（99.9%）and C70（97%）.It has been found that the spectra for C60/C70 and C60 hairs one component lifetime of 388 ps and 379 ps respectively,and the C70 spectrum has two components with lifetimes of 258 ps and 410 ps,respectively.  
        关键词：Fullerite;Positron annihilation   
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        发布时间：2021-04-09
      • Issue 12, (1994)
        摘要：According to simple physical picture and competition mechedsm of positron trapping in defects,a new trap-annihilation model is presented.The characteristics of positron trapping in high To superconducting materials are discussed with this model.It may be useful for discussing non-equilibrium defects in materials.  
        关键词：Positron annihilation;High To superconductor;Trap annihilation model   
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        <引用本文> <批量引用> 8407995 false
        发布时间：2021-04-09
      • Issue 12, (1994)
        摘要：Based on the PATFIT Program package,a modified PAL data Processing system,S--PATFIT,was developed. The modifications include in- line data processing, editing input parameters and displaying output results on full screen,enhancing of graphic displsying etc..Experiences of using the S-PATFIT program were introduced.  
        关键词：Positron annihilation;Data analysis;Full screen parameters editing   
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        <引用本文> <批量引用> 8408007 false
        发布时间：2021-04-09
      • Issue 12, (1994)
        摘要：The mechanism is studied of energy transfer from heavy ions to D atoms which then induce D-D fusion reaction. The Proton yield has been measured from the TiD target in the D（d,p） T reaction induced by 197An bombardmeat in the energy range from 1.0MeV to 5.2MeV.The results can be explained by a two step cascade collision model,which indicates that the energy transfer is carried out by elastic collisions between D atoms and hem ions.  
        关键词：Cool fusion;High temperature fusion;Claster;D-D fusion;Two step cascade collision   
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        <引用本文> <批量引用> 8408015 false
        发布时间：2021-04-09
      • Issue 12, (1994)
        摘要：Obvious increase of hardness and wear lifetime has been observed for high dose pulse Ti,C and Ti+ C dual implanted H13 steel.The Ti+ C dual implantation is better than implantation with other ions.It is shown that the implanted Ti and C concentration can reach 22% and 45% respectively,the over-saturated solid solution of C and Ti appeares,and hardening of solid solution is formed in the implanted layer. The dispersive hardening phases such as Fe2C3,Fe5C2,Fe2Ti and TiC are formed. There is a thin carbon film on the surface of Anplanted layer,increasing surface lubrication.  
        关键词：Pulse Ti+C ion implantation;H13steel;Wear resistance;Augeranalysis;X- ray diffraction   
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        <引用本文> <批量引用> 8408030 false
        发布时间：2021-04-09
      • Issue 12, (1994)
        摘要：Cr ion substituted barium hexaferrite BaFe12-2xCr2xO19 （x=0,1,2,3.5 and 4） has been studied by means of Mossbauer spectroscopy.Cr ions are not found to occupy 4f1 sites at all. For the distribution of Cr ions among 2a,4f2 and 12k sites,our data reveal a random occupation and do not show a remarkable preferential substitution.From Mossbauer spectra for x=4,Cr ions are observed entering 2b sites,but the number off Fe ions substituted by Cr ions in this site is very small.The Carie temperature of the material decreases almost linearly with x at a rate of about 50K/Cr atom.  
        关键词：spectroscopy;Ferrite;Cr substitution;Site occupation   
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        发布时间：2021-04-09
      • Issue 12, (1994)
        摘要：The aim of this paper is to make a survey of the applications of PASCA in studying catalysts of petroleum processing （hydrotheating and catalytic reforming）associated with their surface features,metal-support interaction,MSIC（metal-support interaction complex） formation and development of new types of catalysts.Examples are given for PASCA which may be useful for the design of new catalysts.  
        关键词：PASCA;Catalyst;Chemical monolayer dispersion   
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        发布时间：2021-04-09
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