781 resultados para Y2O3-EU3
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Eu(TTA) 3 MCM 41 ,Eu(TTA) 3 Eu(TTA) 3/MCM 41,XRDHRTEM : ,Eu3 + ,Stokes ; ,MCM 41Eu(TTA) 3
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(P) (Ser) (Cys)Eu3 + PEu3 + SerEu3 + CysEu3 + P SerEu3 + P Cys. , . ,.
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In this paper, the effects of rare earth ions (La3+, Eu3+, Dy3+, Yb3+) and their complexes with calmodulin on the activity of lactate dehydrogenase (LDH) were investigated. The results reveal that whether binding with calmodulin or not, rare earth ions show a minor activation effects on LDH when their concentrations are less than 3 mu mol (.) L-1, but indicate some strong inhibitory effects on LDH activity when the concentrations are above 5 mu mol (.) L-1. Calmodulin, which is a calcium-dependent regulator, can stimulate LDH activity and release the inhibitory effects of rare earth ion. Diethylenetriamine pentaacetic acid(DTPA) and its derivatives bisdimethylamide-diethylenetriamine pentaacetic acid (DTPA-BDMA), bisisonicotinyl-diethylenetriamine pentaacetic acid (DTPA-BIN), which are often used as ligands to metal ions, inhibit LDH activity when their concentrations are above 5 mu mol (.) L-1. Calmodulin can also release their inhibitory effects at the same time.
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The high-resolution emission spectra of KMgF3 : Eu and KMgF3 : Eu-X(X = Ce, Cr, Gd, Cu) single crystals were measured at 300 and 77 K. The vibronic side bands of Eu2+ were characterized and an assignment of the normal mode frequencies to particular vibrations has been made. The correlation between the vibronic frequencies of Eu2+ and the site substitution of other co-dopcd ions was first found. The relationship between vibronic intensity of Eu2+ and other doped ions concentration showed that Cr3+, Gd3+ ions competed K+ sites with Eu2+ ions. Ce3+ and Eu3+ occurred the electron transference. The introduction of Cu+ made for Eu2+ substuting for K+ sites.
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Extraction and separation of Eu3+ and Zn2+ in sulfuric acid solution was investigated by hollow fiber membrane with cyanex 302 (bis (2,4,4-trimethylpentyl) monothiophosphinic acid) in counter-currently circulating operation. Reaction mechanism of membrane extraction and effect of extractant concentration and H+ concentration in aqueous phase on the mass transfer coefficient were discussed. It can be concluded that Zn2+ can be extracted completely from Eu3+ sulfate solution according to the kinetics competing difference. In one extractor process, extraction percentage of Zn2+ was not completely and Eu3+ was not extracted. Extraction percentage of Zn2+ reached 94.92%, but Eu3+ only reached 8.59% after 100 minutes extraction in two series connectors and that of Zn2+ and Eu3+ reached 99.9% and 6.53% respectively after 40 minutes extraction in three series connectors.
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Electroluminescent devices using a ternary europium complex Eu(DBM)(3)(hhpy)(2) (dibenzoylmethane, DBM; hexahydro pyridine, hhpy) as an emitting layer, poly(vinyl-carbazole) (PVK) as a hole-transporting material and tris-(8-hydroxyquinoline) aluminum (Alq(3)) as an electron-transporting material have been fabricated. When only using Eu(DBM)(3)(hhpy)(2) as the emitting layer, luminance of 2.52 cd/m(2) with pure Eu3+ EL emissions from devices is achieved. Introducing a hole transporting material PVK and an electron transporting material 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxidiazole (PBD) in the emitting layer, luminance of 100cd/m(2) is achieved, and the eletroluminescence efficiency is enhanced by about two orders of magnitude. (C) 2001 Elsevier Science B.V. All rights reserved.
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New kinds of hybrid materials containing covalently bonded Eu3+ (Tb3+) bipyridine complexes in a silica network have been prepared and their luminescence properties reported.
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Hybrid materials incorporating Eu-(TTA)(3). 2H(2)O (7hereafter designated as Eu-TTA, with TTA: thenoyltrifluoroacetone) in unmodified or modified MCM-41 by 3-aminopropyl-triethoxysilane (APTES) were prepared by impregnation method. The obtained materials were characterized using X-ray diffraction (XRD), IR and diffuse reflectance spectroscopy and luminescence spectra. All the hybrid samples exhibited the characteristic emission bands of EU3+ under UV light excitation at room temperature, and the excitation spectra showed significant blue-shifts compared to the pure rare-earth complex. Although the red emission intensity in the modified hybrid was almost the half of the red emission intensity in the pure Eu-TTA complex at room temperature, the hybrid showed a much higher thermal stability due to the shielding character of the MCM-41 host.
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Binary complexes of europium and terbium with N-propyl-4-carboxyphthalimide (NP) were prepared and characterized. The luminescence behaviors of the lanthanide complexes as well as their doped silica-based composites were investigated by fluorescence spectra. The results indicated that the lanthanide complexes showed fewer emission lines and slightly lower intensities in silica matrix than that of corresponding pure complexes. The lifetimes of the lanthanide complexes became longer when they were incorporated in silica matrix. (C) 2001 Elsevier Science B.V. All rights reserved.
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Eu3 + YPO4 YVO4 V5+ 0 3 ,VO4 3 - ;V5+ 0 3 ,VO4 3 -Eu3 + , 61 9nm ,Eu3 + YPO4 YVO4 ,P5+ ,Eu3 + YP0 7V0 3 O4 Eu3 + , ,
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Ba Y2 F8 Ce3 + ,Ba Y2 F8 Eu2 + Ba Y2 F8 Ce,Eu, . Ba Y2 F8 Ce F3 Eu F3 Ce3 + Eu2 + Ce3 + Eu3 + . , Ce4 +
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5 0 0 0 0cm- 1 ( 2 0 0nm) , 4f 4f ,4f 5d ,4f 6s ,Dorenbos :E(Ln ,A ) =493 40 -D(A) +ELn ,Ce,Sm3+ Ba3BP3O1 2 4f 5d 170nm ME0Ln :E0Ln(Lnn + Ln(n - 1 ) ) =4 2 73 M-7 776(n =3 4) , M J rgensenEct=[X-M] 3 0 0 0 0cm - 1 ,Er3+Eu3+LiYF4 ErLiYF4 Eu3+Er OEu3+ O ,LiYF4 Eu3+ Eu3+ F ,
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, YAGYAGRE3+ (RE =Eu ,Dy) (1% , ) ,XRD ,TG DTA YAGYAGEu 80 0 90 0Eu3+ YAG , , ,90 0 10 0 0
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(Eu3+ ,Tb3+ )Ca2 Y8(SiO4 ) 6 O2 X (XRD) , (IR) , (SEM) ,XRD 70 0 ,80 0Ca2 Y8(SiO4 ) 6 O2 ,10 0 0Ca2 Y8(SiO4 ) 6 O2 Eu3+ ,Eu3+ 5D0 -7F2 (616nm)Ca2 Y8(SiO4 ) 6 O2 Tb3+ ,5D3-7FJ,5D4 -7FJ(J =6,5 ,4,3 ) ,5D4 -7F5(5 44nm)
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BaLaB9O1 6 RE (RE =Eu ,Tb) , 14 7nm , 15 0nm ,Eu3+ 2 5 0nm ,Tb3+ 4f 5d 15 0 2 60nm , ,
