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Interaction Between Dopants and Native Defects in Zn Doped p-InP Observed by Positron Annihilation

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Chinese Physics Letters 1999年第8期16卷 586-588页

作者： CHEN Zhi-quan wang Zhu wang shao-jie Department of Physics Wuhan UniversityWuhan 430072

Positron lifetime spectra were measured for three Zn doped p-InP samples as a function of temperature. Interaction of Zn dopants and native P vacancies was observed under thermal activation. It is found that the formation of Zn-Vp complex has a correlation with the carrier concentration. The formation mechanism of the complex was tentatively discussed.

关键词： temperature. Defects lifetime

Chemical Quenching of Positronium in CuO/Al2O3 Catalysts

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Chinese Physics Letters 2011年第1期28卷 193-196页

作者： ZHANG Hong-Jun LIU Zhe-Wen CHEN Zhi-Quan wang shao-jie Hubei Nuclear Solid Physics Key Laboratory Department of Physics Wuhan University Wuhan 430072

CuO/Al2O3 catalysts were prepared by mixing CuO and environment of the catalysts are characterized by positron v-AI203 nanopowders. Microstrueture and chemical annihilation spectroscopy. The positron annihilation lifetime measurements reveal two long lifetime components 73 and τ4, which correspond to ortho-positronium （o- Ps） annihilating in mierovoids and large pores, respectively. With increasing CuO content from 0 to 40 wt%, both 3-4 and its intensity I4 show significant decrease, which indicates quenching effect of o-Ps. The para-positronium （p-Ps） intensities derived from multi-Gaussian fitting of the coincidence Doppler broadening spectra also decreases gradually with increasing CuO content. This excludes the possibility of spin-conversion of positronium. Therefore, the chemicM quenching by CuO is probably responsible for the decrease of o-Ps lifetime. Variation in the o-Ps annihilation rate A4 （1/T4） as a function of CuO content can be well fitted by a straight line, and the slope of the fitting line is （1.83 ± 0.05） × 10^7 s-1.

关键词： Catalysts Chemicals Measurement

Reaction of Positronium with Proton in Ultra-stable Y Zeolite Studied by Positrons

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Chinese Physics Letters 2000年第2期17卷 134-136页

作者： ZHU Jun MA Li wang shao-jie LUO Xi-Hui Department of Physics Wuhan UniversityWuhan 430072 Fushun Research Institute of Petroleum and Petrochemicals Fushun 113001

The positron annihilation lifetime spectra were measured as a function of the heating temperature for the ultrastable Y (USY) zeolites. The lifetime spectra were well resolved into five lifetime components, and the longer lifetimes τ3, τ4 and τ5 are assigned to ortho-positronium annihilating in the β-cage, super-cage and the second pore in USY zeolite, respectively. The interesting observation is that the annihilation rate λ5 (the reciprocal ofthe τ5) of the fifth component increases and its intensity I5 decreases with the increasing heating temperature. The result is interpreted in terms of the increase in proton and the reaction between the positronium and proton in USY zeolite after heated.

关键词： temperature lifetime zeolite

Childhood Sexual Abuse and Quality of Life in Chinese Undergraduates: the Mediating Role of Resilience

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Biomedical and Environmental Sciences 2023年第7期36卷 658-662页

作者： WEN Xue LI Yuan LI Yong Han CHANG Jun jie YUAN Meng Yuan CAO Lei Lei wang shao jie SU Pu Yu wang Geng Fu Department of Maternal Childand Adolescent HealthSchool of Public HealthAnhui Medical UniversityHefei 230032AnhuiChina Key Laboratory of Population Health Across Life Cycle(Anhui Medical University) Ministry of Education of the People’s Republic of ChinaHefei 230032AnhuiChina NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract Hefei 230032AnhuiChina

Childhood sexual abuse(CSA)is a widespread and serious public health concern,with long-term impacts on overall health in *** to a systematic review published in 2018,the prevalence of CSA in China ranges from 11.6%to 20.2%[1].A longitudinal study from New Zealand demonstrated that CSA negatively influences a broad range of adult developmental outcomes,including mental disorders,psychological wellbeing,sexual risk-taking,physical health,and socioeconomic wellbeing[2].Therefore,CSA is considered a longterm hazard to the overall health of adults and is associated with poor quality of life(QoL).

关键词： Childhood hazard widespread

Vacancy-Induced Ferromagnetism in SnO_(2) Nanocrystals:A Positron Annihilation Study

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Chinese Physics Letters 2013年第2期30卷 217-220页

作者： CHEN Zhi-Yuan CHEN Zhi-Quan PAN Rui-Kun wang shao-jie School of Nuclear Technology and Chemistry and Biology Hubei University of Science and TechnologyXianning 437100 Hubei Nuclear Solid Physics Key Laboratory Department of PhysicsWuhan UniversityWuhan 430072 School of Materials Science and Engineering Hubei UniversityWuhan 430062

SnO_(2) nanopowders were pressed into pellets and annealed in air from 100 to 1400℃.Both XRD and Raman spectroscopy confirm that all annealed samples were single phase with a tetragonal rutile *** induces an increase in the SnO_(2) grain size from 30 to 83 *** annihilation measurements reveal vacancy defects in the grain boundary region,and the interfacial defects remain stable after annealing below 400℃,then they are gradually recovered with increasing annealing temperature up to 1200℃.Room temperature ferromagnetism was observed for SnO_(2) nanocrystals annealed below 1200℃,and the magnetization decreases continuously with increasing annealing ***,the ferromagnetism disappears at 1200℃ *** shows good coincidence with the recovery of interfacial defects in the nanocrystals,suggesting that the ferromagnetism is probably induced by vacancy defects in the interface region.

关键词： annealing vacancy interfacial

Temperature Dependence of Free Volume in Cross-linked Polyurethane Studied by Positrons

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Chinese Physics Letters 2001年第1期18卷 123-125页

作者： HE Chun-Qing DAI Yi-Qun wang Bo wang shao-jie wang Gui-You HU Chun-Pu Department of Physics Wuhan UniversityWuhan 430072 China Institute of Material Science and Engineering East China University of Science and TechnologyShanghai 200237

Positron annihilation lifetime spectroscopy has been used to study the free volume properties of the cross-linked polyurethane network as a function of temperature in the range from 15K to *** glass transition of polyurethane was observed and the thermal expansion coefficient of the free volume was *** of the ortho-positronium(o-Ps)lifetime distribution shows that the distribution of the free volume in polyurethane is slightly broadened with the increasing temperature in the glassy state,and then significantly broadened with the increasing temperature above the glass transition.

关键词： transition. polyurethane lifetime

Preparation and Structural Characterization of Polystyrene-Rectorite Nanocomposites

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Wuhan University Journal of Natural Sciences 2003年第03A期8卷 817-820页

作者： Fang Peng\|fei, Liu Li\|ming, Zhang Ming, Zhang shao\|ping, wang Bo, wang shao\|jie School of Physics and Technology, Wuhan University, Wuhan 430072, Hubei,China School of Physics and Technology Wuhan University Wuhan Hubei China

The polystyrene/rectorite nanocomposites were prepared by free radical polymerization of styrene containing dispersed organophilic rectorite. The structures and thermal properties of these hybrids have been investigated by X\|ray diffraction (XRD), fourier transform infrared (FT\|IR), positron annihilation spectroscopy (PAS) and thermal gravimetric analysis (TGA) techniques. It was found that exfoliation of rectorite in polystyrene (PS) matrix was achieved. The average free\|volume radius in the PS/clay nanocomposites is generally same as that in PS. Along with increment of rectorite contents, the interface between rectorite and polystyrene matrix increases, and the free\|volume concentration decreases obviously. And the polystyrene nanocomposites have higher thermal decomposition temperature than pure PS.

关键词： polystyrene rectorite nanocomposites positron annihilation spectroscopy

Defects in NTD InP Probed by Positron Annihilation Spectroscopy

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Wuhan University Journal of Natural Sciences 1999年第3期4卷 290-294页

作者： Wen Xiang-e Li Shi-qing Ma Li Yan He-ping wang Zhu wang shao-jie Guo Cheng-zhan Zhao Hai-ge Department of Physics Wuhan University Wuhan China Department of Physics Shenzheng University Shenzheng China

Two samples of high purity InP extracted from the same wafer were examined by positron annihilation spectrum analysis after having been, processed by means of thermal Neutron Transmutation Doping (NTD). Compared with the as grown sample with an average positron lifetime of 246 ps at 300 K, the high dose doped one has an average lifetime of 251 ps and the lower dose doped one 248 ps measured under the same condition, indicating that some defects have been introduced in the NTD process. Annealing experimental results show a steady decrease in the average lifetime with increasing annealing temperature up to 550°C. And a peak in lifetime curve around 500°C was observed which may be attributed to defects related structure conversion. Temperature experiments conducted on the low dose doped sample from 150K to 290 K suggest the existence of vacancy-impurity complex which have given rise to an abnormal reduction of average lifetime with increasing temperature. Also a n-type InP sample (A61) was irradiated with thermal neutrons in another reactor and the lifetime results display an increase of 15 ps. Furthermore, to study epithermal neutron irradiation effects on InP, measurements were performed on an n-type InP sample (N119) along with one p-type sample (P118) after having been irradiated with high fluence of epithermal neutrons. The former has an average lifetime of 262 ps and the latter 247 ps after irradiation. The results prove that on some occassion epithermal neutrons can produce sizable defects in InP.

关键词： NTD InP PAS defects epithermal neutron

Identification of Defects in Undoped Semi-insulating InP by Positron Lifetime

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Chinese Physics Letters 2001年第4期18卷 574-576页

作者： MAO Wei-Dong wang shao-jie wang Zhu SUN Nie-Feng SUN Tong-Nian ZHAO You-Wen Department of Physics Wuhan UniversityWuhan 430072 Hebei Semiconductor Research Institute Shijiazhuang 050051

Positron lifetime measurements,carried out over the temperature range of 10-300 K,have been used to investigate defects in two undoped semi-insulating InP *** positron lifetime spectra were analysed by both PATFIT and MELT *** results at room temperature reveal a positron lifetime around 273 ps,which is associated with indium vacancies VIn or VIn-hydrogen *** positron average lifetime is temperature dependent and decreases with increasing temperature at the beginning(≤80 K and≤120 K),and then keeps unchanged,which is attributed to the influence of negative vacancies and detrapping of the positron from those negative ions of Mg,Zn,Ag,and Ca with ionization level(1-).

关键词： lifetime positron unchanged