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一起换流变绕组差动电流保护动作的分析及改进

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水电能源科学 2024年第10期42卷 211-215页

作者：谢继豪王少杰王永许杨王帅黎慧张磊叶婧三峡大学电气与新能源学院湖北宜昌443002 国网上海市电力公司特高压换流站分公司上海201314

换流变压器的差动保护动作是否正确对于直流系统安全稳定运行至关重要,由于部分换流站在换流变绕组差动保护设计时未考虑谐波制动功能,保护装置无法正确区分励磁涌流和内部故障电流,导致换流变充电时因励磁涌流造成保护误动作。对此,结... 详细信息

换流变压器的差动保护动作是否正确对于直流系统安全稳定运行至关重要,由于部分换流站在换流变绕组差动保护设计时未考虑谐波制动功能,保护装置无法正确区分励磁涌流和内部故障电流,导致换流变充电时因励磁涌流造成保护误动作。对此,结合某换流站在换流变绕组差动保护动作案例进行建模与仿真,分析该换流站换流变压器网侧绕组差动保护动作原因,判断其动作逻辑是否正确。根据空载合闸时的绕组差动电流经滤除直流分量后与标准的正弦电流波形相似性很差的特点,通过仿真分析设定了Hausdorff距离的绕组差动电流保护闭锁判据的整定值,进而避免了换流变充电时因CT饱和特性不一致导致的绕组差动保护误动作。

关键词：换流变压器绕组差动保护励磁涌流波形识别算法

Observation of As-Grown Defects in Zn-Doped GaAs by Positron Lifetime Spectra

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Chinese Physics Letters 2000年第11期17卷 841-843页

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

Positron lifetime spectra were measured for the Zn-doped p-type *** comparing the horizontal-Bridgman-method-grown and the floating-zone-method grown p-type GaAs with the liquid-encapsulation-Czochralski-grown p-type GaAs samples,positron trapping into vacancy type defects was observed in the former two grown p-type *** positron traps were detected,and the dominant ones were attributed to acceptor the in p-type GaAs.

关键词： positron attributed floating

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： Condensed matter: electrical magnetic and optical Surfaces interfaces and thin films Condensed matter: structural mechanical & thermal Chemical physics and physical chemistry

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

秸秆不同还田模式下磷钾释放特征及其对玉米产量的影响

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中国土壤与肥料 2024年第1期 157-165页

作者：刘熙明王滢渺田洪涛任姿姿王少杰高强冯国忠吉林农业大学资源与环境学院/吉林省商品粮基地土壤资源可持续利用重点实验室吉林长春130118

连续两年(2021—2022年)在吉林省四平市设置田间定位试验,采用尼龙网袋法测定覆盖(SM)和翻压(SB)两种秸秆还田方式和不施氮肥(N0)、180 kg·hm^(-2)(N180)两种施氮水平下秸秆磷、钾释放率,旨在明确黑土区玉米秸秆磷、钾释放规律对还田... 详细信息

连续两年(2021—2022年)在吉林省四平市设置田间定位试验,采用尼龙网袋法测定覆盖(SM)和翻压(SB)两种秸秆还田方式和不施氮肥(N0)、180 kg·hm^(-2)(N180)两种施氮水平下秸秆磷、钾释放率,旨在明确黑土区玉米秸秆磷、钾释放规律对还田方式和氮肥管理的响应及其对玉米产量的影响。结果表明,还田方式与施氮显著影响秸秆磷、钾释放,SB处理秸秆磷两年累积释放率平均为69.7%,显著高于SM处理的54.5%;与N0处理相比,施氮处理秸秆磷释放率提高了12.3%。SB处理秸秆钾两年累积释放率平均为95.6%,显著高于SM处理的94.2%;而施氮对秸秆钾累积释放影响同样显著,肥料氮素投入使秸秆钾累积释放率提高1.1%。通过对秸秆磷、钾替代潜力的估算,认为秸秆磷对磷肥(P2O5)替代潜力较低,为9.1 kg·hm^(-2);但秸秆钾对钾肥(K_(2)O)替代潜力较高,为141.0 kg·hm^(-2)。两年间还田方式对玉米产量无明显影响,但玉米穗粒数存在一定差异。SB处理玉米穗粒数为430粒·穗^(-1),显著高于SM处理的409粒·穗^(-1)。而施氮则明显促进了产量的形成,提高了玉米产量,与N0处理相比,两年玉米产量平均增加7707 kg·hm^(-2)。通过结合秸秆磷、钾养分释放综合分析,认为在黑土区充足氮素供应条件下以翻压方式进行秸秆还田,秸秆释放的磷、钾养分有利于穗粒的形成,从而保障产量稳定。

关键词：秸秆还田方式施氮秸秆磷秸秆钾玉米产量

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