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spectroscopic investigations on yb^3+ doped and Pr^3+/yb^3+ codoped tellurite glasses for photonic applications

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Journal of Rare Earths 2021年第1期39卷 33-42,I0002页

作者： M.seshadri M.J.v.Bell v.Anjos y.Messaddeq Grupo de Engenharia e Espectroscopia de Materiais Departamento de Fisica-ICEUniversidade Federal de Juiz de ForaJuiz de ForaMG36036-900Brazil Centre d'Optique Photonique et Laser2375 Rue de la TerrasseUniversite LavalQuebecQCG1V 0A6Canada

In this work we repo rt on structural and spect roscopic properties of yb^3+doped and Pr^3+/yb^3+co-doped TeO2-Bi2 O3-ZnO-Li2 O-Nb2 O5(TBZLN)tellurite *** and stretching modes of TeO2 and Te-OH bond(strong and weak)were analysed from the deconvolution of observed Raman and FT-IR *** on the absorption measurements,the energy bands of yb^3+and Pr^3+ions are *** spectroscopic properties for the radiative transitions of yb^3+and Pr^3+ions were reported using McCumber and Judd-Ofelt *** emission bands originating from 3 P1 and 3 P0 to lower lying levels of Pr^3+were registered under 447 nm *** emission band around 1334 nm assigned to the Pr3:1 G4→3 H5 was observed when excited at 980 *** stimulated emission cross-section(σemi(λ))and effective linewidth(Δλeff)for the 3 P1→3 H6,3 P1→3 H5,3 P0→3 H6,3 P0→3 F2,3 P1→3 F3,3 P1→3 F4,3 P0→3 F4 and 1 G4→3 H5 transitions of Pr^3+are *** luminescence in Pr^3+/yb^3+codoped glass upon 980 nm excitation was *** resonant transfer processes between yb^3+and Pr^3+ions are presented and *** chromaticity co-ordinates were also evaluated from the visible emission spectra showing that Pr^3+/yb^3+co-doped glass may be suitable for the development of yellow-orange(λexc=447 nm)and near white light(λexc=980 nm)emitting devices in photonics.

关键词： Rare earth ions Tellurite glass spectroscopic properties Upconversion luminescence

Investigation of thermal evolution of nanodomain structures in nonlinear barium sodium niobate crystals

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Chinese Optics Letters 2008年第2期6卷 143-145页

作者： s.v.Ivanova P.N.Lebedev Physical Institute of RAs Leninsky pr.53 Moscow 119991Russia

By the 90° elastic light scattering investigation and far field observation in the range of 20 - 800 ℃, the relation between behavior of light scattering anomalies and evolution of nanodomain structures in lattice of barium sodium niobate （Ba2NaNb5O15, BsN） crystal was clarified. The correlation between anomalies on the temperature curves of the elastic light scattering intensity and temperature transformations of nanodomains was studied by X-ray and electron microscope methods. Phase transition near 500 ℃ and movement in field of scattering light could be explained by appearance of a new incommensurate phase.

关键词： Elastic scattering Light fields Light intensity Light scattering Transmission electron microscopy X ray microscopy

Esterification of levulinic acid to n-butyl levulinate over heteropolyacid supported on acid-treated clay

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Journal of Natural Gas Chemistry 2011年第1期20卷 18-24页

作者： s. Dharne v. v. Bokade Catalysis Division National Chemical Laboratory (CSIR)

Levulinic acid has been identified as a promising green, biomass-derived platform chemical. n-Butyl levulinate is used as an important intermediate having diverse applications. The present work focuses on the synthesis of n-butyl levulinate by esterification of levulinic acid with n-butanol using heteropolyacid （HPA） supported on acid-treated clay montmorillonite （K10）. 20% （w/w） dodecatungestophosphoric acid （DTPA） supported on K10 was found to be the most efficient catalyst with 97% levulinic acid conversion and 100% selectivity towards n-butyl levulinate. Effects of various process parameters were studied to examine the efficacy of 20% （w/w） DTPA/K10 for optimization of the activity.

关键词： levulinic acid n-butanol dodectungestophosphoric acid K10 n-butyl levulinate

Microstructure and mechanical properties of new Mg-Zn-y-Zr alloys with high castability and ignition resistance

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International Journal of Minerals,Metallurgy and Materials 2024年第12期31卷 2714-2726页

作者： T.A.Koltygina v.E.Bazhenov A.v.Koltygin A.s.Prosviryakov N.y.Tabachkova I.I.Baranov A.A.Komissarov A.I.Bazlov National University of science and Technology MIsIs Moscow 119049Russia A.M.Prokhorov General Physics Institute Russian Academy of SciencesMoscow 119991Russia Moscow state University of Medicine and Dentistry Moscow 127473Russia

Complex studies of new Mg-Zn-y-Zr system alloys have been carried *** content range for the formation of the two-phase structure Mgss(Mg solid solution)+LPsO(long-period stacking ordered)in alloys of the Mg-Zn-y-Zr system was determined by thermodynamic *** effect of heat treatment regimes on microstructure,mechanical,and corrosion properties was *** fluidity,hot tearing tendency,and ignition temperature of the alloys were *** best combination of castability,mechanical,and corrosion properties was found for the Mg-2.4Zn-4y-0.8Zr *** alloys studied are superior to their industrial counterparts in terms of technological properties,while maintain high corrosion and mechanical *** increased level of pro-perties is achieved by a suitable heat treatment regime that provides a complete transformation of the 18R to 14H modification of the LPsO phase.

关键词： metals and alloys liquid-solid reactions microstructure fluidity mechanical properties corrosion transmission electron mi-croscopy

synthesis and photoluminescence studies of Ba(Gd,Ln)B_9O_(16):Eu^(3+)(Ln=La,y) phosphors for n-Uv LED lighting and display devices

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Journal of Rare Earths 2015年第2期33卷 140-147页

作者： v.v.Rangari s.J.Dhoble Department of Physics RTM Nagpur University

BaGdB9O16：Eu^3＋ and Ba（Gd,Ln）B9O16：Eu^3＋（Ln=La, y） phosphors were synthesized by solid state diffusion method. The X-ray diffraction, scanning electron microscopy（sEM） and photoluminescence properties were investigated. The as-synthesized BaGdB9O16：Eu^3＋ and Ba（Gd,Ln）B9O16：Eu^3＋（Ln=La, y） phosphors showed strong red emission under ultraviolet light excitation. By partially substituting Gd^3＋ by La^3＋ and y^3＋ ions in the host BaGdB9O16：Eu^3＋ materials, the maximum emission intensity was observed for the optimum composition of BaGd0.91La0.8B9O16Eu0.01 phosphor. The experimental results indicated that the Eu doped BaGdB9O16 and Ba（Gd,Ln）B9O16（Ln=La, y） phosphors were promising red phosphors, which might find potential applications in near-Uv excited LED lighting as well as display devices. Comparison of as-synthesized phosphors with standard phosphor used in CFL（compact fluorescent lamp） was also done. Energy transfer mechanism of Gd^3＋ to Eu^3＋ was also discussed in this paper.

关键词： phosphor solid state diffusion display devices photoluminescence rare earths

Left atrial appendage occluder implantation for stroke prevention in elderly patients with atrial fibrillation： acute and long-term results

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Journal of Geriatric Cardiology 2017年第9期14卷 590-592页

作者： Karapet v Davtyan Andrey A Kalemberg Arpi H Topchyan Georgiy y simonyan Ekaterina v Bazaeva victoria s shatahtsyan Laboratory for Interventional Arrhythmia Treatment of “National Medical Research Center for Preventive Medicine” Ministry of Healthcare of the RussianFederation Petroverigskiy lane Moscow Russia

Atrial fibrillation （AF） is the most common cardiac ar-rhythmia in clinical practice with an increasing incidenceand prevalence. With ageing, the risk of thromboembolicand hemorrhagic events increases dramatically. As it hasbeen reported previously, 3-year survival rate among pa-tients with AF over 75 years of age after stroke is less than50%, and almost 90% of those patients will remain dis-abled.

关键词： Left atrial appendage closure Oral anticoagulation therapy stroke prevention The elderly

ON THE BURN REsIsTANCE OF Ti-35v-15Cr-0.05C TITANIUM ALLOy

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Acta Metallurgica sinica(English Letters) 1998年第3期11卷 202-206页

作者： G.P.Li D.Li y.y.Liu Q.J.Wang s.X.Guan Q.C.Li Inst of Metal Research The Chinese Acad of Sciences Shenyang China

The Ti-35v-15Cr-0.05C (wt% is a new nonburning titanium alloy. The test for alloy combustibility was carried out by using CO2 laser. A 430 watt and 6mm diameter laser spot impinges directly on the sample within normal atmospheric pressure and temperature. The results show that the ignition time of the nonburning titanium alloy is the longest in the eight examined titanium alloys, and is 3.5 times that of TC4 alloy. The ignition tempeerature of the nonburning alloy is 2991° C, and is higher than that of TC4 alloy by 1976°C. On the condition of high tempeerature and rich oxygen,the surface of alloy forms a melting layer which plays roles of oxygen insulation, heat insulation and burning products insulation. This is the mechanism of combustion resistance.

关键词： Ti-35v-15Cr-0.05C (wt%) nonburning titanium alloy combustion resistance

Evolution of microstructure and texture in copper during repetitive extrusion-upsetting and subsequent annealing

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Journal of Materials science & Technology 2017年第7期33卷 690-697页

作者： Q.Chen D.y.shu J.Lin y.Wu X.s.Xia s.H.Huang Z.D.Zhao O.v.Mishin G.L.Wu state Key Laboratory of Mechanical Transmission Chongqing University Chongqing 400044 China

The evolution of the microstructure and texture in copper has been studied during repetitive extrusionupsetting（REU） to a total von Mises strain of 4.7 and during subsequent annealing at different temperatures. It is found that the texture is significantly altered by each deformation pass. A duplex 001 ＋ 111 fiber texture with an increased 111 component is observed after each extrusion pass,whereas the 110 fiber component dominates the texture after each upsetting pass. During REU, the microstructure is refined by deformation-induced boundaries. The average cell size after a total strain of 4.7 is measured to be ~0.3 μm. This refined microstructure is unstable at room temperature as is evident from the presence of a small number of recrystallized grains in the deformed matrix. Pronounced recrystallization took place during annealing at 200？C for 1 h with recrystallized grains developing predominantly in high misorientation regions. At 350？C the microstructure is fully recrystallized with an average grain size of only 2.3 μm and a very weak crystallographic texture. This REU-processed and subsequently annealed material is considered to be potentially suitable for using as a material for sputtering targets.

关键词： severe plastic deformation Repetitive extrusion-upsetting Copper Deformation microstructure Texture Annealing

Processes underlying the laser photochromic effect in colloidal plasmonic nanoparticle aggregates

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Chinese Physics B 2020年第3期29卷 412-419页

作者： A E Ershov v s Gerasimov I L Isaev A P Gavrilyuk s v Karpov Institute of Computational Modeling sB RAs 660036KrasnoyarskRussia siberian Federal University Krasnoyarsk660041Russia Kirensky Institute of Physics Federal Research Center KSC SB RAS660036KrasnoyarskRussia siberian state University of science and Technology Krasnoyarsk 660014Russia

We have studied the dynamic and static processes occurring in disordered multiparticle colloidal Ag aggregates with natural structure and affecting their plasmonic absorption spectra under pico-and nanosecond pulsed laser radiations, as well as the physical origin responsible for these processes. We have shown that depending on the duration of the laser pulse,the mechanisms of laser modification of such aggregates can be associated both with changes in the resonant properties of the particles due to their heating and melting(picosecond irradiation mode) and with the particle shifts in the resonant domains of the aggregates(nanosecond pulses) which depend on the wavelength, intensity, and polarization of the *** mechanisms result in formation of a narrow dip in the plasmonic absorption spectrum of the aggregates near the laser radiation wavelength and affect the shape and position of the dip. The effect of polydispersity of nanoparticle aggregates on laser photochromic reaction has been studied.

关键词： nanoparticle surface plasmon resonance photochromic process pulsed laser radiation