982 resultados para Tm^3
Propriedade fotoluminescente da ZrO2: Tb+3, Eu+3, Tm+3 obtida pelo mtodo de polimerizao de complexos
Resumo:
Recent studies are investigating a new class of inorganic materials which arise as a promising option for high performance applications in the field of photoluminescence. Highlight for rare earth (TR +3 ) doped, which have a high luminous efficiency, long decay time and being able to emit radiation in the visible range, specific to each element. In this study, we synthesized ZrO2: Tb +3 , Eu +3 , Tm +3 nanoparticles complex polymerization method (CPM). We investigated the influences caused by the heat treatment temperature and the content of dopants in zirconia photoluminescent behavior. The particles were calcined at temperature of 400, 500 and 600 C for two hours and ranged in concentration of dopants 1, 2, 4 and 8 mol% TR +3 . The samples were characterized by thermal analysis, X-ray diffraction, photoluminescence of measurements and uv-visible of spectroscopies. The results of X-ray diffraction confirmed the formation of the tetragonal and cubic phases in accordance with the content of dopants. The photoluminescence spectra show emission in the region corresponding simultaneous to blue (450 nm), green (550 nm) and red (615 nm). According to the results, ZrO2 particles co-doped with rare earth ions is a promising material white emission with a potential application in the field of photoluminescence
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MoSb_2O_5R_2O_3R'_2O_3Bi_2O_3Bi~(3+)ThorntonBa_2BiSbO_6Ba_2GdSbO_6EECEHKOM_2RSbO_6 (M = BaSrCa, R = La Y)M_2RSbO_6Sm~(3+)Eu~(3+)Dy~(3+)Ho~(3+)Er~(3+)Tm~(3+)Bi~(3+)Bi~(3+)X-M_2RSbO_6(M = BaSrR = LaYGdBi)Fm3mOhCa_2YSbO_6P_(21)M_2RSbO_6 (M = BaSrCa; R = GdYBi)Ba_2GdSbO_6Sb_2O_5M_2RSbO_6Sb_2O_3520 Sb_2O_5Eu~(3+)Ba_2YSbO_6:Eu~(3+)Br_2YSbO_6:Eu~(3+), Bi~(3+)254nmEu~(3+)595nmBi~(3+)325nmBi~(3+)Eu~(3+)Eu~(3+)595nmBi~(3+)Eu~(3+)Bi~(3+)~1S 3P_1Eu~(3+)~5D_0~5D_0 7F_1Eu~(3+)Sr_2YSbO_6:Eu~(3+)Sr_2YSbO_6:Eu~(3+), Bi~(3+)245nmEu~(3+)595nmBi~(3+)335nmBi~(3+)Eu~(3+)Ba_2YSbO_6:Eu~(3+)Ba_2YSbO_6:Eu~(3+), Bi~(3+)Eu~(3+)Ca_2YSbO_6:Eu~(3+)Ca_2YSbO_6:Eu~(3+), Bi~(3+)396nmEu~(3+)613nmBi~(3+)313nmBi~(3+)Eu~(3+)Bi~(3+)3P_1 ~1S_0400nmEu~(3+)~7F_0 ~5L_6396nm~5L_6~5D_0~7F_2Ca_2Y_(0.96)Eu_(0.04)SbO_6Eu~(3+)Eu~(3+)Fm3m Ba_2YSbO_6Sr_2YSbO_6Oh~5D_0 ~7F_1Eu~(3+)P_(21)~5D_0 ~7F_2M_2YSbO_6:R~(13+)(M = BaCa; R' = SmDyHoErTm)Sm~(3+)Dy~(3+)Ho~(3+)Bi~(3+)Ca_2YSbO_6:Bi~(3+)Bi~(3+)240nm~1S_0 ~1P_1315nm~1S_0 ~3P_1400nm~3P_1 ~1S_0
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N_2-H_2M_2~ICO_3 + M_3~(II)(PO_4)_2 + M_2~(III)O_3 + (NH_4)_2HPO_4 + M~(II)F_2 M_x~IM_(10-2x)~(II)M_x~(III)(PO_4)_6F_2 + NH_3 + H_2OM~I = Li~+, Na~+, K~+; M~(II) = Ca~(2+), Sr~(2+); M~(III) = Y~(3+), La~(3+), Gd~(3+); X = 0.5, 1, 2, 3XEu~(3+)M_(10)~(II)(PO_4)_6F_2(Pb_3/m)ac9.416.89 AM~I, M~(II)M~(III)XCe~(3+)Na_2Ca_6La_2(PO_4)_6F_2Ce~(3+)Ce~(3+)-Mn~(2+), Ce~(3+)-Re~(3+) (Re~(3+) = Pr~(3+)Nd~(3+)Sm~(3+)Tb~(3+)Dy~(3+)Tm~(3+)Ho~(3+)Er~(3+))Ce~(3+)-Mn~(2+)-Re~(3+) (Re~(3+) = Dy~(3+), Nd~(3+))Na_2Ca_6La_2(PO_4)_6F_2:Ce~(3+)338358nm~2D-~2F_(5/2)~2D-~2F_(1/2)~2D-~2F_(6/2)~2D-~2F_(7/2)Ce~(3+)F~-Ce~(3+)-Ce~(3+)Ce~(3+)Mn~(2+)Ce~(3+)Re~(3+)A. Ce~(3+)-Sm~(3+)Tb~(3+)Dy~(3+)Tm~(3+)BCe~(3+)-Nd~(3+)Pr~(3+)C. Ce~(3+)-Ho~(3+), Er~(3+)ABCe~(3+)(_T)_A > (_T)_BCe~(3+)-Ho~(3+)Ce~(3+)-Er~(3+)Ho~(3+)Er~(3+)Ce~(3+)Ce~(3+)-Mn~(2+)-Re~(3+)Ce~(3+)Mn~(2+)Re~(3+)Ce~(3+)-Mn~(2+)-Re~(3+)Ce~(3+)-Mn~(2+)Ce~(3+)-Re~(3+)Ce~(3+)-Mn~(2+)-Re~(3+)M. YokataCe~(3+)Ce~(3+)-Mn~(2+)Ce~(3+)-ReCe~(3+)-Mn~(2+))-Re~(3+)Ce~(3+)Ce~(3+)Ce~(3+)(_f, _R)
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The mechanism involved in the Tm(3+)((3)F(4)) -> Tb(3+)((7)F(0,1,2)) energy transfer as a function of the Tb concentration was investigated in Tm:Tb-doped germanate (GLKZ) glass. The experimental transfer rate was determined from the best fit of the (3)F(4) luminescence decay due to the Tm -> Tb energy transfer using the Burshtein model. The result showed that the 1700 nm emission from (3)F(4) can be completely quenched by 0.8 mol% of Tb(3+). As a consequence, the (7)F(3) state of Tb(3+) interacts with the (3)H(4) upper excited state of TM(3+) slighting decreasing its population. The effective amplification coefficient beta(cm(-1)) that depends on the population density difference Delta n = n((3)H(4))-n((3)F(4)) involved in the optical transition of Tm(3+) (S-band) was calculated by solving the rate equations of the system for continuous pumping with laser at 792 nm, using the Runge-Kutta numerical method including terms of fourth order. The population density inversion An as a function of Tb(3+) concentration was calculated by computational simulation for three pumping intensities, 0.2, 2.2 and 4.4 kWcm(-2). These calculations were performed using the experimental Tm -> Tb transfer rates and the optical constants of the Tm (0.1 mol%) system. It was demonstrated that 0.2 mol% of Tb(3+) propitiates best population density inversion of Tin(3+) maximizing the amplification coefficient of Tm-doped (0.1 mol%) GLKZ glass when operating as laser intensity amplification at 1.47 mu m. (C) 2007 Elsevier B.V. All rights reserved.
Resumo:
Transformation of cells in tissue culture results in a variety of cellular changes including alterations in cell growth, adhesiveness, motility, morphology, and organization of the cytoskeleton. Morphological and cytoskeletal changes are perhaps the most readily apparent features of transformed cells. Although a number of studies have documented a decrease in the expression of specific tropomyosin (TM) isoforms in transformed cells, it remains to be determined if the suppression of TM synthesis is essential in the establishment and maintenance of the transformed pheno-type. To address the roles of different TM isoforms in transformed cells we have examined the effects of expressing specific TM isoforms in transformed cells using a Kirsten virus-transformed cell line (ATCC NRK1569) as a model system. In contrast to normal fibroblasts, the NRK 1569 cells contain reduced levels of TM-1 and undetectable levels of TM-2 and TM-3. These cells have a rounded morphology and are devoid of stress fibers. Employing expression plasmids for TM-2 and TM-3, stable cell lines were established from the NRK 1569 cells that express these isoforms individually. We demonstrate that expression of TM-2 or TM-3 leads to increased cell spreading accompanied by the formation of identifiable microfilament bundles, as well as significant restoration of well-defined vinculin-containing focal adhesion plaques, although expression of each isoform exhibited distinct properties. In addition, cells expressing TM-2, but not TM-3, exhibited contact-inhibited cell growth and a requirement for serum.
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"November 1976."
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Er^3+Tm^3+/Yb^3+Raman980nmLD(476nm)(530nm545nm)(656nm)(476nm)Tm^3+1^G43^3H6(530nm545nm)Er^3+2^H11/24^I1524^S3/24^I15/2(6
Resumo:
Er3+, Yb3+ and Tm3+ codoped fluorophosphate glasses emitting blue, green and red upconversion luminescence at 970 nm laser diode excitation were studied. It was shown that Tm3+ behaves as the sensitizer to Er3+ for the green upconversion luminescence through the energy transfer process: Tm 3+:H-3(4) + Er3+:I-4(15/2) -> Er3+:I-4(9/2) + Tm3+:H-3(6), and for the red upconversion luminescence through the energy transfer process: Tm3+:F-3(4) + Er3+:I-4(11/2) -> TM3+:H-3(6) + Er3+:4 F-9/2. Moreover, Er3+ acts as quenching center for the blue upconversion luminescence of TM3+. The sensitization of Tm3+ to Er3+ depends on the concentration of Yb3+. The intensity of blue, green and red emissions can be changed by adjusting the concentrations of the three kinds of rare earth ions. This research may provide useful information for the development of high color and spatial resolution devices and white light simulation. (C) 2006 Elsevier B.V. All rights reserved.
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The thermal stability, Raman spectrum and upconversion properties of Tm^(3+)/Yb^(3+) co-doped new oxyfluoride tellurite glass are investigated. The results show that Tm^(3+)/Yb^(3+) co-doped oxyfluoride tellurite glass possesses good thermal stability, lower phonon energy, and intense upconversion blue luminescence. Under 980-nm laser diode (LD) excitation, the intense blue (475 nm) emission and weak red (649 nm) emission corresponding to the 1G4 -> 3H6 and 1G4 -> 3F4 transitions of Tm^(3+) ions respectively, were simultaneously observed at room temperature. The possible upconversion mechanisms are evaluated. The intense blue upconversion luminescence of Tm^(3+)/Yb^(3+) co-doped oxyfluoride tellurite glass can be used as potential host material for the development of blue upconversion optical devices.
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Novel oxyfluoride glasses are developed with the composition of 30SiO(2)-15Al(2)O(3)-28PbF(2)-22CdF(2)-0.1TmF(3)-xYbF(3) -(4.9-x) AlF3(x = 0, 0.5, 1.0, 1.5, 2.0) in mol fraction. Furthermore, the upconversion luminescence characteristics under a 970nm excitation are investigated. Intense blue, red and bear infrared luminescences peaked at 453nm, 476nm, 647nm and 789nm, which correspond to the transitions of Tm3+: D-1(2) -> F-3(4), (1)G(4) -> H-3(6), (1)G(4) -> F-3(4), and H-3(4) -> H-3(6), respectively, are observed. Due to the sensitization of Yb3+ ions, all the upconversion luminescence intensities are enhanced considerably with Yb3+ concentration increasing. The upconversion mechanisms are discussed based on the energy matching rule and quadratic dependence on excitation power. The results indicate that the dominant mechanism is the excited state absorption for those upconversion emissions.
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2Tm^3THo^3Er^3294m
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DCJTB18-1DCJTBASEDCJTBPS016mJPulse~(_1)cm-24072cm-1249cml704DCMDCJTB2ASEASEDCJTBPSASEASElordDCJTBTETM3Alq3DCJTBC545TAlq3ASEAlq3Alq3Alq34418-186018
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BSBaF_2BaF_2:CeTSLBaF_2TSL381K402KCeTSLKMgF_3KCaF_3BaLiF_3TSLESRKMgF_3KMgF_3KCaF_3Al~(3+)FBaLiF_3La~3Yb~(3+)FH10~8RadBaLiF_3FAFXESREuEu~(3+)KMgF_3KMgF_3:Eu~(2+)0.29mol%BaLiF_3:Eu~(2+)PSLXBSKMgF_3BaLiF_3XLa~(3+)Tm~(3+)KMgF_3K~+Mg~(2+)SEMH_2SO_4cf KMgF_3BaLiF_3LaF_3:Ce~(3+)Ce~(3+)Ce~(3+)BSCeF_3
