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Modification of Optical Bandgap of Thin Silicon Films Induced by 94 MeV Xe Ion Irradiation
YANG Cheng-shao, WANG Zhi-guang, , SUN Jian-rong, YAO Cun-feng, ZANG Hang, WEI Kong-fang, GOU Jie, MA Yi-zhun, SHEN Tie-long, SHENG Yan-bin, ZHU Ya-bing, LI Bing-sheng, FU Yun-chong,
2010, 27(1): 92-96. doi: 10.11804/NuclPhysRev.27.01.092  Published:2010-03-20
Keywords: silicon, thin film, heavy ion irradiation, optical bandgap
Monocrystalline silicon(cSi), thin films of amorphous silicon(aSi) and nanocrystalline silicon(ncSi) were irradiated at room temperature(RT) by using 94 MeV Xeions at 1.0×1011, 1.0×1012 or 1.0×1013 Xeions/cm2, respectively. All samples were analyzed at RT by an UV/VIS/NIR spectrometer (Lambda 900, PE, Germany), and then the uariation of the optical bandgap with the irradiation fluence was investigated systematically. The results show that the optical bandgap of the silicon samples irradiates by Xeion changed dramatically with different crystalline structures. For the aSi thin films, the optical bandgap values decreased gradually from ~1.78 to ~1.54 eV with increasing Xeion irradiation fluence. For the ncSi thin films, the optical bandgap values increased sharply from ~1.50 (origin) to ~1.81 eV(Φ=1.0×1012ions/cm2), and then decreased to ~1.67 eV(Φ=1.0×1013 ions/cm2). However, there is no observable change of the optical bandgap of the cSi after Xeion irradiations. Possible mechanism on the modification of the silicon thin films was briefly discussed.
Nuclear Density Empirical Formula of Nucleus and Nuclear Effect in lA DIS Process
WANG Yan-zhao, ZHANG Hong-fei, , GAO Yong-hua, HOU Zhao-yu, ZUO Wei
2008, 25(3): 232-235. doi: 10.11804/NuclPhysRev.25.03.232  Published:2008-09-20
Keywords: nuclear density model, nuclear density empirical formula of nucleus, binding energy, l-A DIS process
The nuclear effect functions in lA DIS process RHe/D(x, Q2), RLi/D(x, Q2), RC/Li(x, Q2) and RCa/Li(x, Q2) are calculated on the basis of the nuclear density model by using nuclear densities obtained from an empirical formula or the experimental values of the electromagnetic mean of radius square 〈r2〉, respectively.It is shown that the nuclear effect functions obtained from the empirical formula are in good agreement with the NMC experimental data, and better than the later ones.The empirical formula of the nuclear density can be used to study the nuclear effect of nucleon structure functions reasonably.
Study on Radiation Sterilization of Electron Beam Accelerator
WU Zhen-hua, , XUE Lin-gui, LU Xi-hong, ZHANG Zi-min,
2009, 26(1): 80-83. doi: 10.11804/NuclPhysRev.26.01.080  Published:2009-03-20
Keywords: microorganism, electron beam accelerator, sterilization by ionizing radiation, dosage
To study the effects of radiation sterilization of the electron beam, the three species of microorganisms, Escherichia. coli, Staphylococcus aureus and Proteus vulgaris were irradiated with the electron beam, delivered by the electron accelerator independently developed by the Institute of Modern Physics, Chinese Academy of Sciences, and the changes of superoxide dismutase (SOD) activity of these irradiated microorganisms were also tested. The results indicated that the Staphylococcus aureus were fully radiosterilized with the radiation dosage of 2.0 kGy, but 2.2 kGy to the Escherichia.coli and Proteus vulgaris. Moreover, the data also demonstrated that the irradiation had noticeable effects on the SOD activity of the three microorganisms.
Influences of Atom Ar on Ar@C60+Ar@C60 Collisions
ZHAO Qiang, ZHANG Feng-shou, , ZHOU Hong-yu
2007, 24(2): 160-163. doi: 10.11804/NuclPhysRev.24.02.160  Published:2007-06-20
Keywords: embedded Ar fullerene, collision, dimer, molecule dynamics
A semiemperical molecular dynamics model was developed. The central collisions of C60 +C60 and Ar@C60 +Ar@C60 at the same incident energy were investigated within this model. The fullerene dimers could be formed by a selfassembly of C60 fullerene, and the new fullerene structure like “peanut” could be formed by a selfassembly of Ar@C60 . It was found that atom Ar had a great effect on the collision of Ar@C60 +Ar@C60 .