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Nanocrystalline rare earth fluorides doped with Pr^(3+) ions

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Journal of Rare earths 2016年第8期34卷 802-807页

作者： Marcin Runowski Stefan lis Department of Rare earths Faculty of Chemistry Adam Mickiewicz University

Praseodymium（III） doped CeF3, CeF3：Gd, LaF3, GdF3 and YF3 inorganic fluorides were precipitated in an aqueous, sur- factant-free solution, using Nh4F as a source of fluoride ions. The as-prepared products were subjected to a hydrothermal treatment, which led to the formation of crystalline nanoluminophores, composed of spherical （30 nm） and elongated （40-200 nm） nanos- tructures. Due to the presence of Pr3＋ ions, the synthesized nanomaterials showed yellow luminescence under a blue light irradiation. The nanoluminophore based on the YF3 host revealed the most promising spectroscopic properties, i.e., bright and intensive emission, hence it was investigated in detail. The photophysical properties of the nanomaterials obtained were studied by powder X-ray diffrac- tion （XRD）, transmission electron microscopy （TeM） and spectrofluorometry, i.e., measurements of excitation/emission spectra and luminescence decay curves.

关键词： yellow luminescence lanthanide fluorides Pr3+ doping nanocrystals hydrothermal post-treatment Ce3+ quenching rare earths

Photoluminescence properties of nanosized strontium-yttrium borate phosphor Sr_3Y_2(BO_3) _4:eu^(3+) obtained by the sol-gel Pechini method

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Journal of Rare earths 2011年第12期29卷 1161-1165页

作者： A.A.Shyichuk S.lis Department of Rare earth Faculty of ChemistryAdam Mickiewicz Uniwersity

Mixed strontium-yttrium borate phosphor Sr3Y2（BO3）4 doped with eu^3＋ ions was obtained by the sol-gel Pechini method. Crystal structure of the synthesized compound was analyzed by X-ray powder diffraction. Optimal conditions for the synthesis were found. Photophysical properties of the phosphor samples were investigated by collecting excitation and luminescence spectra as well as measuring lumi- nescence lifetime. Judd-Ofelt analysis showed that eu^3＋ ions occupied Y^3＋ sites in the crystalline network. The studied compound showed a red emission with the quantum yield of 54%-55% and can be potentially used as phosphor for plasma display panels and luminescent tubes.

关键词： strontium-yttrium borate luminophor eu^3+ sol-gel method rare earths

Synthesis of luminescent KY_3F_(10) nanopowder multi-doped with lanthanide ions by a co-precipitation method

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Journal of Rare earths 2016年第8期34卷 808-813页

作者： Szymon Goderski Marcin Runowski Stefan lis Department of Rare earths Faculty of Chemistry Adam Mickiewicz University

A series of KY3F10 nanophosphors doped with Gd3＋, Ce3＋ and eu3＋ ions were obtained with the use of a co-precipitation method. The resulting products were white precipitates, consisting of spherical particles with diameter about 150-200 nm, which was confirmed using transmission electron microscopy （TeM） technique. Powder X-ray diffraction （XRD） and energy dispersive X-ray analysis （eDX） measurements confirmed appropriate structures of the nanoparticles obtained. Spectroscopic properties of the prod- ucts were examined on the basis of the measured excitation/emission spectra and luminescence decay curves. The synthesized sam- ples showed orange-red luminescence, characteristic for eu3＋ ions. The reaction process was performed in required alkaline ph ad- justed with the use of ethylenediaminetetraacetic acid （eDTA） and potassium hydroxide. The samples containing large amounts of Gd3＋ dooant ions exhibited a tendencv to form nroducts with different momhologies.

关键词： : fluorides co-precipitation nanophosphors luminescence nanopowders Ce3+/Gd3+/eu3+ doping rare earths

Photoluminescent properties of LaF_3:eu^(3+) and GdF_3:eu^(3+)nanoparticles prepared by co-precipitation method

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Journal of Rare earths 2009年第4期27卷 588-592页

作者： T.Grzyb S.lis Department of Rare earths Faculty of Chemistry Adam Mickiewicz University

GdF3：eu^3＋ and GdF3：eu^3＋ nanoparticles were prepared by a co-precipitation method in the presence of the chelating agent, citric acid. The structural properties of the products were characterized by X-ray diffraction （XRD） and transmission electron microscopy （TeM）. The average crystallite size was estimated from the full-width at half-maximum （FWhM） of the diffraction peaks by the Scherrer equation. The sizes of the nanoparticles were 12 nm for LaF3：eu3＋ and 17 nm for GdF3：eu^3＋. The luminescent properties of the nanoparticles were investigated by excitation and emission spectra. energy transfer from Gd3＋ to eu3＋ was observed.

关键词： nanofluorides phosphors luminescence energy transfer rare earths

Dynamic stress concentration in an infinitely long cylindrical cavity due to a point spherical source embedded within a fluid-saturated poroelastic formation of infinite extent

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Applied Mathematics and Mechanics(english edition) 2025年第1期46卷 139-156页

作者： h.hOSSeINI O.BALILAShAKI Department of Mechanical engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident spherical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. Stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

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Neuroinflammation as a therapeutic target in huntington's disease

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Neural Regeneration Research 2025年第3期20卷 817-818页

作者： Andrea Kwakowsky Thulani h.Palpagama Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CentreUniversity of GalwayGalwayIreland

In 1872, George huntington presented his essay “On Chorea” to the Meigs and Mason Academy of Medicine and, in doing so, detailed a disease that would later bear his name. huntington's disease(hD) is a genetic, neurodegenerative disease that manifests as the loss of motor control,cognitive impairment,and mood and psychiatric changes in paents.

关键词： huntington inflammation Medicine

Glial response in the midcingulate cortex in huntington’s disease

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Neural Regeneration Research 2025年第1期20卷 207-208页

作者： Thulani h.Palpagama Andrea Kwakowsky Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CenterUniversity of GalwayGalwayIreland

huntington’s disease(hD)is a genetic disease characterized by the progressive degeneration of the striatum and *** can present with a variety of symptoms that can broadly be classified into motor symptoms,inclusive of choreatic movements and rigidity,mood and psychiatric symptoms,such as depression and apathy,and cognitive symptoms,such as cognitive *** causal mutation underlying hD results from an expansion of a CAG repeat sequence on the IT15 gene,resulting in the formation and accumulation of a mutant huntingtin protein.

关键词： huntington degeneration cortex

Photoluminescence and electrochemiluminescence studies of chosen rare earths systems

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Journal of Rare earths 2008年第2期26卷 192-197页

作者： Stefan lis Slawomir But Krzysztof Staninski Monika Jesiolowska Department of Rare earths Faculty of Chemistry Adam Mickiewicz University Grunwaldzka 6

eu（Ⅲ） complexes with chosen Keggin polyoxomatalates, POM, containing organic counter cations （tetrabutylarnmonium, tetrabutylphosphonium, triphenylethylphosphonium）, were synthesized, and their photophysical properties were studied. The synthesized complexes had the general formula of Xnh5-n[euSiW11O39], formulated based on the results of elemental and thermogravimetric analysis and FTIR spectroscopy. The photophysical properties of the obtained compounds were investigated using photoluminescence and electrochemiluminescence, eCL, methods in solutions and solids. The most intense luminescence of eu（Ⅲ） was observed for the complexes with tetrabutylarnmonium cations. After the addition of phenanthroline to the Xnh5-n[euSiW11O39] solutions, a large increase in the eu（Ⅲ） luminescence intensity and a lengthening of its luminescence lifetime were observed as a result of the formation of ternary complexes. Attempts to apply eCL as a method of light emission by generating species capable of forming excited states in Ln/POMs, i.e., Tb（Ⅲ） and eu（Ⅲ） in the Na9euW10O36 and Na9TbW10O36 complexes, were made. The influence of the POM complexes on the eCL was also tested using the Tb/eDDhA （eDDA=ethylenediamine di（o-hydroxyphenylacetic acid）） complex, which is effective in generating eCL.

关键词： Ln(Ⅲ) luminescence electrochemiluminescence polyoxometalates complexes rare earths

Structure modeling of terbium doped strontium-lanthanum borate

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Journal of Rare earths 2014年第3期32卷 248-253页

作者： A.Shyichuk S.lis G.Meinrath Department of Rare earths Faculty of Chemistry Adam Mickiewicz University Radioactivity environment Remediation (ReR) Consultants

Terbium doped strontium-lanthanum borate, Sr3La2（BO3）4：Tb （SLB）, was studied by semi-empirical computational ap- proaches using PM6 parametrization and the SPARKLe model for lanthanide（Ⅲ）（Ln（Ⅲ）） cations. The focus of interest was on structural aspects, e.g. the cell parameters and distribution of dopant ions between various sites as a function of dopant concentration. The cell linear dimensions were calculated to decrease linearly with increasing dopant molar concentration. SLB offered two sites for the dopant. Calculations predicted that one of these sites should be preferred by the Tb（Ⅲ） dopant. The optimized cell dimensions as well as the total energies differed for structures with dopant exclusively in site 1 or site 2. Computational predictions were tested against experimental results obtained for SLB synthesized by sol-gel method varying the dopant concentration. The agreement be- tween experimental and computational results was found sufficiently promising to continue the computational studies.

关键词： strontium-lanthanum borate terbium structure calculations rare earths