最新刊期
卷 0 ， 期 0 ， 2020
- 摘要：The transient diffusion processes in low-temperature epitaxial growth of Cu thin film on Cu（100） have been studied and classified by using molecular dynamics simulations with a hydrid tight-binding-like potential. The statistics indicate that the noticeable contribution to the surface mobility of adatoms comes from the impact cascade diffusion mechanism. Meanwhile, the observed oscillations of diffraction intensity show that a quasi layer-by-layer growth may take place at the temperature as low as 100K in the initial stage of thin-film formation.关键词：Molecular dynamics simulation;Transient diffusion mechanism;Low- temperature epitaxy
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发布时间：2021-04-09 - 摘要：The energy stability of the 4MV accelerator has been measured by monitoring the r-ray yields of the 27Al（p,p’ r ）27A1 reaction. The energy stability became better after replacement of power supply for the focusing lens of the accelerator.关键词：Prompt nuclear reaction;Proton-beam energy stability;Scanning proton microprobe
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发布时间：2021-04-09 - 摘要：The TiHx film prepared by chemical adsorption is annealed. When temperature is above 343℃, the concentration of hydrogen varies significantly. The depth profiles of hydrogen in TiHx samples annealed at 343℃ for different time are determined by ERD with 3MeV 4He. The mechanism of thermal release behavior of hydrogen is discussed. When the annealing time is long enough, a hydrogen peak at the sample surface can be observed. It is confirmed by high energy He+ backscattering that the carbon contaminated at the surface during the experiments or/and the film preparation can strongly influence the release behavior of hydrogen.关键词：Hydrogen;Thermal release;Elastic recoil detection;Impurity
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发布时间：2021-04-09 - 摘要：It is indicated in this paper that relative annihilation intensity, Ii（0）, which comes from the analysis of the lifetime spectrum and is usually regarded as a basis of discussion on the experiment, dose not always have exact physical meaning. Instead, either the relative population of positrons in the ith state, Ni（0）, or the probability density of positrons distributed in the states, ni（0）, being equal to Ni（0）/∑Ni（0） = τiIi（0）/∑Ni（0）, has obvious connection physically with the structure and characters of the annihilation medium. A proof of the above propositions based on the two- state capture model is given.关键词：Positron annihilation;Intensity;Lifetime;Probability density
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发布时间：2021-04-09 - 摘要：The ion beam optics of a microwave ion gun for a focused ion beam （FIB） system is investigated numerically in this article. Considering the ion beam optics of the gun as a two-stage acceleration system consisting of plasma electrode and Orloff-Swason lens, effects of some primary parameters on the beam divergence are examined. The results show that beam divergence of the system depends mainly on the extraction perveance and voltage ratio, and a minimum beam divergence can be obtained under optimum conditions.关键词：Microwave ion gun;Numerical simulation;Ion beam optics
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发布时间：2021-04-09 - 摘要：The drift of a high precision stabilized power supply for the storage ring and the methods to improve its current stability are discussed. After a series of reformation the stability has been improved and more reliable light can be provided.关键词：Current-stabilized power supply;Drift;Storage ring
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发布时间：2021-04-09 - 摘要：The adsorption and desorption behaviors of W and Re on anion exchange column and acidic alumina column have been studied. Radiochemical procedures are presented for the separation of W and Re. The experimental results show that a satisfactory separation between W and Re can be achieved. The radiochemical procedures will be useful to separate radiotherapeutical nuclide 186Re from W target which is irradiated with a high intensity proton beam.关键词：Rhenium;Tungsten;Chromatographic separation;Anion exchange;Acidic alumina
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发布时间：2021-04-09 - 摘要：Microdosimetric spectra and radial dose distribution of 252 Cf a particles were measured by a large volume cylindrical flowing tissue-equivalent proportional counter（TEPC）. Because a particles enter into the TEPC without a window, the probability of energy deposition per ion Rb is 1. The measured dose-mean specific energy z1D（Gy） from single-event varies with b’ the radial distance from the track core, according to the formula z1D=ab-x. where a = 0.328 and x=1.7 when b<0.6482 μm. and a = 0.288 and x = 2 when 6≥0.6482μm. The method to determine the maximum radial distance （penumbra） is given.
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发布时间：2021-04-09 - 摘要：This paper reveals the problems involved in using red phosphorus as the flame retardant in the radiation crosslinked PE foam and the methods to solve them. It is found that use of capsulated red phosphorus or red phosphorus mixed with some titanate coupling agent can increase the blending of red phosphorus with PE and thus improve the quality and processing properties of products. A better composition of flame retarding PE foam is therefore obtained.
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发布时间：2021-04-09 - 摘要：Dry wheat seeds were irradiated with heavy ions belonging to three different energy regions. The indoor experimental method and culture process in the field for the irradiated seeds are introduced. Preliminary results on half-lethal dose, cytological observation and breeding situation are presented. Finally, the mutation mechanisms of crop breeding are disussed according to three different energy regions.关键词：Energetic heavy ion;Ion implantation;Ion penetration;Crop breeding;Mutation mechanism
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发布时间：2021-04-09 - 摘要：The preparation of uranous nitrate in UO2（NO3）2-HNO3-N2H5NO3-H2O system by continuous electrolytic reduction with a three-stage series electrolytic cell has been studied. When the concentrations of U（VI ）, HNO3, N2H5NO3 in feeding solution are maintained at 180g/L, 3.14mol/L, 0.21mol/L respectively and the feeding rate is controlled at about 200mL/h, the uranous nitrate solution with the U（IV） concentration over 150g/L can be obtained successively under the optimum conditions.
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发布时间：2021-04-09 - 摘要：This thesis introduces a microcomputer coal-ash analyzer based on MCA, in which the signals from two different r-ray energies regions are accepted and analysed. Its analytical error is 2%-3% in comparison with chemical analysis,and it can be used in on-line analysis system after some improvements.关键词：Coal ash content;r-ray;Mass absorption coefficient
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发布时间：2021-04-09 - 摘要：The radiolysis of starch by using r-rays from 60Co was described. The effects of both irradiation dose and dose rate on starch’s viscosity were studied,and the generated quantity of carboxyl in the irradiated starch was determined. The storage stability, thermal stability of viscosity, and colour change for irradiated starch were also observed. Applications of the irradiated starch in some fields were introduced.关键词：Starch;Radiolysis;Low-viscosity starch
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发布时间：2021-04-09 - 摘要：The HI-13 tandem accelerator has been operated at CIAE for more than ten years. The operation and maintenance experiences and main improvements on the acceleretor are briefly described in the paper.关键词：Tandem accelerator;Operation experience;Maintenance;Laddertron
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发布时间：2021-04-09
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