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Luminescence and Microstructure of Sr_2Mg(BO_3)_2 Doped with Eu

Journal of Rare Earths 2005年第S1期23卷 48-50页

作者：曹林刘行仁荆西平刘玉兰陈英 Department of Material Physics University of Science and Technology Beijing Beijing 100083 China fujian joinluck electronic enterprise co. ltd. Fuzhou 350007 China co.lege of Chemistry Peking University Beijing 100871 China Research School of Physical Sciences and Engineering the Australian National University Canberra ACT 0200 Australia

Sr_2Mg(BO_3)_2 doped with Eu was synthesized respectively in air and weak reducing atmosphere (co.bustion of carbon particle), whose photoluminescence characteristics and structure were also studied at room-temperature. In air, the fluorescent body′s co.or was white for different synthesized temperatures. At room temperature, the sample was excited and showed red typical emission spectrum of Eu 3+ whose emission apex were sharp near 612 nm and emission spectrum was made up of the charge transformation band (CTB) of Eu 3+ and excitation spectrum of 4f→4f high energy level transition, then reached the area of VUV. However, under reducing atmosphere (co.bustion of carbon particles), the co.or of the sample yielded was yellow, whose co.or became deeper with increasing temperature and showed phase transition. Using UV excitation, the luminescence of yellow sample was very weak. In a co.plicated broad spectrum at visible light area,the red emission spectrum of Eu 2+ was not observed. Crystal structure and luminescence of the sample were co.pletely different from the results of Diaz and Keszler. Two samples were prepared under oxidation and reducing atmosphere at high temperature, which were different on crystal structure and microstructure. By studying Sr_2Mg(BO_3)_2∶Eu 3+ a series of directional faults or educts were found, because Eu 3+ ions substituted for Sr 2+ ions. However, microstructure of Sr_2Mg(BO_3)_2∶Eu 2+ is more co.plicated, whose excitation spectrum might be excited by Eu 2+. By XRD patten of the samples, phase transition co.ld be found. Twins and clusters that were formed from point defect such as interstitial atom and big angle crystal boundary co.ld be found by TEM.

关键词： luminescence borate microstructure rare earths

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Using of sparse principal co.ponent analysis for identifying critical locations of the active distribution system

Using of sparse principal component analysis for identifying...

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第36届中国控制会议

作者： Peixiang Zheng Bin Chen Yuanliang Fan Gonglin Zhang Yang Liu State Grid fujian Electric Power co. Ltd State Grid fujian Electric Research Institute fujian Provincial enterprise Key Laboratory of High Reliable Electric Power Distribution Technology co.lege of Electrical and electronic Engineering Shandong University of Technology

ISBN: (纸本)9781538629185

This paper presents a method for the identification of critical locations of power systems using the measurable variables of the active distribution *** critical locations are identified using sensitive sparse principal co.ponent analysis（SSPCA） where the loadings of some variable in principal co.ponents are restricted to *** is tested on the UK 77-bus ***,SSPCA and principal co.ponent analysis were investigated and the results analyzed and *** two methods provided co.parable results in identification of critical *** validity and potential of SSPCA are demonstrated through simulation and a co.parative *** identification of critical locations in a power system will enable power operators/engineers using limited resources for prioritization of these locations for Phasor Measurement Units（PMUs） and other advanced measurement systems deployment.

关键词： critical locations active distribution grid sensitive sparse principal co.ponent critical variable steady state

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