最新刊期
卷 0 ， 期 0 ， 2020
- 摘要：Bothh radial and longitudinal energy deposition distributions along the track of 25MeV/u 40 Ar 14+ ions in tissue equivalent gas have been studied by a wall less proportional counter system Two gas pressure values of 6 4kPa and 0 5kPa,simulating 5μm（size of a nucleus）and 0 4μm（size of a supersolenoid）respectively,were chosen to perform the experiment A brief discussion was given关键词：Tissue equivalent gas;Energy deposition;Heavy ions
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发布时间：2021-04-09 - 摘要：The effect of γ irradiation on the creep properties of GH33A, a high temperature Ni base alloy, is investigated Creep curves, positron lifetimes and Doppler broadening spectra are measured The results show that plasticity of the non magnesium sample is greatly increased （38 1%） after irradiation, while the breaking lifetime keeps constant However, both lifetime and plasticity for the Mg containing （0 0045wt%） sample are reduced After negative creep load, lifetime of the irradiated non Mg sample increased （9 4%）, but plasticity decreased（25 6%） After irradiation and negative creep load, lifetime of the long aged alloy with Mg content of 0 0054% is increased significantly （48 3%）, while plasticity remain unchanged关键词：GH33A alloy;γ irradiation;Creep;Positron annihilation
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发布时间：2021-04-09 - 摘要：The current array detectors for high energy X or γ radiography are introduced and some specific features of the gas pressurized array ion chambers project are indicated An array ion chamber developed in Tsinghua University is described and its characteristics measured on a 9MeV linear accelerator are given The applications of the array ion chamber to the large container truck scanner and industrial non destructive testing are illustrated关键词：X or γ radiography;Array detector;Non destructive testing;Ionization chamber
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发布时间：2021-04-09 - 摘要：The EDXRF method was used to find the concentration of component elements in blue and white porcelain It was found that some elements in colorant were diffused towords glaze layer when the porcelain had been fired at high temperature Through the half value thickness calculation, the contribution of some elements from the procelain’s body to the measured intensity was also confirmed The experiment also indicated that the contents of various elements in the glaze layer of non decorated portions were definite in spite of the measuring sites, while those of some elements in decorated portions were dependent on positions关键词：EDXRF;Blue and white porcelain;Non destructive testing;Diffusion phenomenon;Half value thickness
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发布时间：2021-04-09 - 摘要：The H13 steel sample was implanted with Mo+C dual ions produced by a MEVVA ion facility with an extracting voltage of 40kV The ion dose was 6×10 17 /cm 2 for Mo and 9×10 17 /cm 2 for C respectively Simple Mo and C ion implantation experiments were also carried out Anodic polarization tests show that the dual ion implantation can improve H13 samples corrosion resistance, but no further improvement on the corrosion resistance was found for the Mo+C implanted sample after annealing The topography and surface composition of the samples were analyzed by SEM and AES respectively关键词：Ion implantation;Corrosion resistance;Surface modification
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发布时间：2021-04-09 - 摘要：A method is presented to determine the half life of weakly populated high spin isomeric state from the coincident intensity ratio between the γ rays feeding and depopulating the isomer measured under different coincidence time windows Half lives for four isomeric states in 197 Bi were obtained by using this method关键词：Intensity ratio;Isomeric state;γ γ t coincidence
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发布时间：2021-04-09 - 摘要：The synthesis of[1 14 C]palmitic acid via Grignard Reaction is reported The carbon C 14 dioxide was liberated by dropping sulfuric acid onto barium carbonate C 14 The yield of [1 14 C] palmitic acid was 44 8% A radiochemical purity of more than 99 5% was determined by HPLC and the product was proved to be free of impurity by TLC关键词：C]palmitic acid;Grignard Reaction;Synthesis
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发布时间：2021-04-09 - 摘要：A method of measuring moisture in glass materials （silicon sand and mixture） using a thermal neutron transmission gauge is reported Both theoretical calculation and experimental calibration indicate that the thermal neutron transmission gauge is suitable for high speed measurement of moisture in glass materials The precision of moisture measurement （2σ） is better than 0 5% for the samples of more than 40g关键词：Thermal neutron transmission gauge;Glass materials;Moisture measurement
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发布时间：2021-04-09 - 摘要：The epithermal neutron activation analysis of uranium was studied to deter mining trace uranium via 239 U（T 1/2 =23 5min） produced by the 238 U（n, γ） reaction with boron nitride （BN） as shielding material to reduce the interference from major elements Al, Cl and Na The detection limits of uranium are 8ng/g for biological materials and 0 15μg/g for geological samples, respectively An analytical time of less than one hour per sample is possible The contents of uranium in 15 biological and geological standard reference materials were determined, with a good agreement with the certified values关键词：Uranium;Epithermal neutron activation analysis;Short half life nuclides;Standard reference materials
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发布时间：2021-04-09 - 摘要：A new neutron tube with an annular alpha particle detector has been reported Since it gives both direction and time signals of emitted neutrons, the new tube can effectively suppress the γ ray background in the logging关键词：Well logging neutron tube;Annular alpha particle detector;Background
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发布时间：2021-04-09 - 摘要：The computer software is introduced of a low level liquid scintillation counter with such functions as automatic sample changing, data acquisition and processing关键词：Liquid scintillation counter;Computer system;14 C dating;Tritium content;Low background
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发布时间：2021-04-09 - 摘要：Up to 43 glaze and body samples of ancient and modern Chinese Jun Porcelain and other porcelain are chosen and contents of 36 elements for each sample are determined by NAA The NAA data are then analysed by the fuzzy cluster method The result shows that although the ancient Jun Porcelain samples span leaped 600years and are from different kilns and their glaze colors are utterly different,they have a long term,stable and mainly the same supply of raw material The relation between ancient Jun Porcelain and ancient Ru Porcelain is also preliminarily analysed It is found that only few modern Jun Porcelain samples are similar to ancient Jun Porcelain but the majority of them are different from ancient ones关键词：Neutron activation analysis;Fuzzy cluster analysis;Chinese Jun Porcelain
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发布时间：2021-04-09 - 摘要：This paper briefly describes the design of a beam pulsing system for the 600kV intense pulsed beam accelerator,the structure of the buncher cavity and the measurements of its static features,the beam dynamics calculations,the RF power system and some experimental results关键词：Chopper;Buncher;Particle longitudinal motion;Beam pulse
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发布时间：2021-04-09
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