These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Structural and optical properties of lanthanide oxides grown by atomic layer deposition (Ln = Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb).  

PubMed

Ln2O3 thin films with optically active f-electrons (Ln = Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb) have been grown on Si(100) and soda lime glass substrates by atomic layer deposition (ALD) using Ln(thd)3 (Hthd = 2,2,6,6-tetramethyl-3,5-heptanedione) and ozone as precursors. The temperature range for depositions was 200-400 °C. Growth rates were measured by spectroscopic ellipsometry and a region with a constant growth rate (ALD window) was found for Ln = Ho and Tm. All the compounds are grown as amorphous films at low temperatures, whereas crystalline films (cubic C-Ln2O3) are obtained above a certain temperature ranging from 300 to 250 °C for Nd2O3 to Yb2O3, respectively. AFM studies show that the films were smooth (rms < 1 nm) except for depositions at the highest temperatures. The refractive index was measured by spectroscopic ellipsometry and was found to depend on the deposition temperature. Optical absorption measurements show that the absorption from the f-f transitions depends strongly on the crystallinity of the material. The clear correlation between the degree of crystallinity, optical absorptions and refractive indices is discussed. PMID:23774891

Hansen, Per-Anders; Fjellvåg, Helmer; Finstad, Terje; Nilsen, Ola

2013-08-14

2

Large-scale synthesis of Lu{sub 2}O{sub 3}:Ln{sup 3+} (Ln{sup 3+} = Eu{sup 3+}, Tb{sup 3+}, Yb{sup 3+}/Er{sup 3+}, Yb{sup 3+}/Tm{sup 3+}, and Yb{sup 3+}/Ho{sup 3+}) microspheres and their photoluminescence properties  

SciTech Connect

Graphical abstract: In this work, multicolor and monodisperse Lu{sub 2}O{sub 3}:Ln{sup 3+} (Ln{sup 3+} = Eu{sup 3+}, Tb{sup 3+}, Yb{sup 3+}/Er{sup 3+}, Yb{sup 3+}/Tm{sup 3+}, and Yb{sup 3+}/Ho{sup 3+}) microspheres were prepared by a homogeneous precipitation method followed by a subsequent calcination process. Display Omitted Highlights: ? Lu{sub 2}O{sub 3}:Ln{sup 3+} microspheres were prepared by a precipitation followed by a calcination process. ? Lu{sub 2}O{sub 3}:Eu{sup 3+}/Tb{sup 3+} samples exhibit respective red or green emissions. ? Lu{sub 2}O{sub 3}:Yb{sup 3+}/Er{sup 3+}/Tm{sup 3+}/Ho{sup 3+} exhibit emissions of green, blue, yellow-green, respectively. ? These finding may find potential applications in bioanalysis and field emission displays. -- Abstract: In this work, multicolor and monodisperse Lu{sub 2}O{sub 3}:Ln{sup 3+} (Ln{sup 3+} = Eu{sup 3+}, Tb{sup 3+}, Yb{sup 3+}/Er{sup 3+}, Yb{sup 3+}/Tm{sup 3+}, and Yb{sup 3+}/Ho{sup 3+}) microspheres were prepared by a homogeneous precipitation method followed by a subsequent calcination process. X-ray diffraction (XRD), Fourier transformed infrared (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) spectra, and cathodoluminescence (CL) spectra were employed to characterize the samples. Upon ultraviolet and low-voltage electron beams excitation, Lu{sub 2}O{sub 3}:Ln{sup 3+} (Ln{sup 3+} = Eu{sup 3+} and Tb{sup 3+}) samples exhibit respective bright red (Eu{sup 3+}, {sup 5}D{sub 0} ? {sup 7}F{sub 2}) and green (Tb{sup 3+}, {sup 5}D{sub 4} ? {sup 7}F{sub 5}) down-conversion (DC) emissions. Under 980 nm NIR irradiation, Lu{sub 2}O{sub 3}:Ln{sup 3+} (Ln{sup 3+} = Yb{sup 3+}/Er{sup 3+}, Yb{sup 3+}/Tm{sup 3+}, and Yb{sup 3+}/Ho{sup 3+}) exhibit characteristic up-conversion (UC) emissions of green (Er{sup 3+}, {sup 4}S{sub 3/2}, {sup 2}H{sub 11/2} ? {sup 4}I{sub 15/2}), blue (Tm{sup 3+}, {sup 1}G{sub 4} ? {sup 3}H{sub 6}) and yellow-green (Ho{sup 3+}, {sup 5}F{sub 4}, {sup 5}S{sub 2} ? {sup 5}I{sub 8}), respectively. These finding may find potential applications in bioanalysis, optoelectronic and nanoscale devices, field emission displays, and so on.

Gao, Yu, E-mail: gaoy777@126.com [College of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China)] [College of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China); Gong, Jian [Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China)] [Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China); Fan, Miaomiao [Department of Medical Pharmaceutical, Shenyang Chemical Industry School, Shenyang 110142 (China)] [Department of Medical Pharmaceutical, Shenyang Chemical Industry School, Shenyang 110142 (China); Fang, Qinghong; Wang, Na; Han, Wenchi; Xu, Zhenhe [College of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China)] [College of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China)

2012-12-15

3

Multifunctional ScF3:Ln3+ (Ln = Tb, Eu, Yb, Er, Tm and Ho) nano/microcrystals: hydrothermal/solvothermal synthesis, electronic structure, magnetism and tunable luminescence properties.  

PubMed

A facile, hydrothermal/solvothermal route has been developed to synthesize a series of multifunctional lanthanide ion (Tb(3+), Eu(3+), Yb(3+), Tm(3+), Er(3+) and Ho(3+))-activated ScF3 nanocrystals. The morphology and size of ScF3 can be tuned in a controlled manner by altering the additives and volume ratios of H2O?:?EtOH in the initial solution. Under ultraviolet (UV), vacuum ultraviolet (VUV) or low-voltage electron-beam excitation, the as-obtained Tb(3+), Eu(3+) codoped ScF3 product exhibits multicolor photoluminescence (PL) and cathodoluminescence (CL), and possible luminescence mechanisms are discussed. Moreover, under 980 nm excitation, upconversion (UC) emissions have been achieved in Yb(3+)-Er(3+), Yb(3+)-Tm(3+), and Yb(3+)-Ho(3+) codoped ScF3. Ferromagnetic property of ScF3 is detected due to the nanocrystal defects. The results obtained indicate that the lanthanide ion-doped ScF3 nanocrystals exhibit multicolor UV/VUV PL, CL, and UC luminescence as well as ferromagnetic properties. Thus, they may have potential applications in PL areas, field emission display devices, bioseparation and magnetic resonance imaging. PMID:24759954

Han, Lili; Wang, Yuhua; Guo, Linna; Zhao, Lei; Tao, Ye

2014-06-01

4

Experimental study of the 4fn ? 4fn and 4fn ? 4fn-15d1 transitions of the lanthanide diiodides LnI2 (Ln=Nd, Sm, Eu, Dy, Tm, Yb)  

NASA Astrophysics Data System (ADS)

The diffuse reflectance and photoluminescence (PL) spectra of NdI2, SmI2, EuI2, DyI2, TmI2 and YbI2 were measured between 225 and 12 500 nm in order to determine their 4fn ? 4fn-15d1 optical bandgaps. The results were compared with those obtained using an empirical model of the electronic structure of LnI2. The results can be used to explain the lanthanide valency and crystalline structure changes of other lanthanide diiodides such as PrI2.

Rogers, E.; Dorenbos, P.; de Haas, J. T. M.; van der Kolk, E.

2012-07-01

5

Syntheses, structure and rare earth metal photoluminescence of new and known isostructural A{sub 2}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) compounds  

SciTech Connect

Nine new A{sub 2}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Ce, Pr, Eu, Tb, Ho, Er, Tm, Yb, Lu) compounds have been synthesized by solid-state reactions. They are isostructural with six reported analogues of yttrium and other lanthanides and the monoclinic unit cell parameters of all fifteen of them vary linearly with the size of A{sup 3+} ion. Single crystal X-ray structures of eight A{sub 2}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Ce, Pr, Eu, Gd, Tb, Ho, Er, Tm) compounds have been determined. Neat A{sub 2}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, Er, Tm) compounds exhibit characteristic rare earth metal photoluminescence. -- Graphical abstract: Among the fifteen isostructural A{sub 2}Mo{sub 4}Sb{sub 2}O{sub 18} (A=rare earth metal) molybdoantimonites, eight (A=Pr, Sm, Eu, Tb, Dy, Ho, Er, Tm) compounds exhibit neat characteristic lanthanide photoluminescence in the 200-800 nm range at room temperature. Display Omitted Research highlights: {yields} Syntheses of nine new A{sub 2}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Ce, Pr, Eu, Tb, Ho, Er, Tm, Yb, Lu) compounds. {yields} X-ray structures of eight A{sub 2}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Ce, Pr, Eu, Gd, Tb, Ho, Er, Tm) compounds. {yields} Photoluminescence of neat A{sub 2}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, Er, Tm) compounds.

Mohitkar, Shrikant A.; Kalpana, G. [Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036 (India); Vidyasagar, K., E-mail: kvsagar@iitm.ac.i [Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036 (India)

2011-04-15

6

Upconversion processes in Yb-sensitized Tm:ZBLAN  

SciTech Connect

A spectroscopic study of 22 rare-earth-ion doped ZBLAN (fluorozirconate) glass was done to study feasibility of sensitizing Tm:ZBLAN with Yb to facilitate development of an efficient, conveniently pumped blue upconversion fiber laser. it was found that, under single-color pumping, 480 nm emission from Tm{sup 3+} was strongest when Yb,Tm:ZBLAN is excited at 975 nm; the strongest blue blue emission was obtained from a glass sample with 2.0 wt% Yb + 0.3 wt% Tm. Also, for weak 975 nm pump intensities, strength of blue upconversion emission can be greatly enhanced by simultaneously pumping at 785 nm. This increased upconversion efficiency is due to reduced number of energy transfer steps needed to populate the Tm{sup 3+} {sup 1}G{sub 4} energy level. Measurements of fluorescence lifetimes vs dopant concentration were also made for Yb{sup 3+}, Tm{sup 3+}, and Pr{sup 3+} transitions in ZBLAN in order to better characterize concentration quenching effects. Energy transfer between Tm{sup 3+} and Pr{sup 3+} in ZBLAN is also described.

Carrig, T.J. [Coherent Technologies, Inc., Lafayette, CO (United States); Cockroft, N.J. [Los Alamos National Lab., NM (United States)

1996-10-01

7

Frequency upconversion in Tm- and Yb:Tm-doped silica fibers  

NASA Astrophysics Data System (ADS)

Frequency upconversion has been observed and studied in Tm 3+-doped and Yb 3+-sensitized Tm 3+-doped silica fibers. In the singly doped fiber upconversion to the blue and UV has been observed under excitation in the red (660 nm) and infra-red (1.064 ?m). In the co-doped fiber upconversion has also been observed under excitation at around 800-900 nm.

Hanna, D. C.; Percival, R. M.; Perry, I. R.; Smart, R. G.; Townsend, J. E.; Tropper, A. C.

1990-08-01

8

Spectrum upconversion and downconversion in (Tm3+,Yb3+) and (Tb3+,Yb3+) co-doped fluorosilicate glass  

NASA Astrophysics Data System (ADS)

We investigated the upconversion and downconversion luminescence in (Tb3+, Yb3+) and (Tb3+, Yb3+) co-doped lithiumlanthanum- aluminosilicate oxyfluoride glass. Upon excitation at 980 nm, where crystalline CdTe solar cells no longer absorb, the sub-bandgap photons can be converted to the higher-energy ones via upconversion. In addition, under excitation between 470 nm and 490 nm, one blue photon might be split up to two near-infrared ones via downconversion. The downconversion luminescence matches the spectral response of crystalline Si solar cell well. We observed much more intense upconversion luminescence from (Tm3+, Yb3+) codoped glass than that from ( Tb3+, Yb3+) codoped glass under the same 980 nm excitation conditions. Our results indicate that the sequential energy transfer from Yb3+ ions to Tm3+ ions is much more efficient than the cooperative energy transfer from Yb3+ ions to Tb3+ ions.

Pan, Z.; Akrobetu, R.; Morgan, S. H.

2013-09-01

9

Enhanced 1.8 ?m emission in Yb3+/Tm3+ co-doped tellurite glass: Effects of Yb3+?Tm3+ energy transfer and back transfer  

NASA Astrophysics Data System (ADS)

The ~1.8 ?m emission characteristics of Tm3+ by a direct excitation and through an energy transfer process upon sensitization with Yb3+ ions in tellurite glass are reported. The spectroscopic properties of Tm3+ ions have been evaluated by applying Judd-Ofelt theory on the measured absorption spectrum. The obtained intensity parameters, ?2=7.155×10-20 cm2, ?4=3.325×10-20 cm2, ?6=1.278×10-20 cm2 are used to estimate the radiative properties of Tm3+ ions in the present glass host. A ~10 fold enhancement in the Tm3+ 1.8 ?m emission observed with 16 fold reduced emission of Yb3+ ions (1008 nm) in co-doped sample on Yb3+ ions excitation illustrates the efficient energy transfer from Yb3+: 2F5/2?Tm3+: 3H5. The energy transfer process assisted by host phonon energy has been discussed by using relevant theoretical models and estimated the energy transfer micro-parameters. Effect of energy back transfer Tm3+?Yb3+ on NIR and upconversion emissions have been discussed. An efficient ~1.8 ?m with comparatively higher emission cross-section 1.115×10-20 cm2 on account of reduced upconversion emissions has been achieved in the present tellurite glass.

Balaji, Sathravada; Biswas, Kaushik; Sontakke, Atul D.; Gupta, Gaurav; Annapurna, Kalyandurg

2014-11-01

10

Biosorption of La, Eu and Yb using Sargassum biomass  

Microsoft Academic Search

Biosorption of the lanthanides: Lanthanum (La3+), Europium (Eu3+) and Ytterbium (Yb3+) from single-component and multi-component batch systems using Sargassum polycystum Ca-loaded biomass was studied. The ion exchange sorption mechanism was confirmed by the release of calcium ions from the biomass that matched the total number of metal and protons removed from the solution. The metal binding increased with pH due

Vivian Diniz; Bohumil Volesky

2005-01-01

11

Intense red upconversion luminescence from Tm3Yb3 codoped transparent glass ceramic  

E-print Network

Intense red upconversion luminescence from Tm3Yb3 codoped transparent glass ceramic Wei Xu,1 by 980 nm laser were greatly quenched by cross relaxation and the 700 nm luminescence from Tm3:3F2;3 3H6 transition was strongly enhanced. A nearly monochromatic red luminescence band was observed. Based

Cao, Wenwu

12

Up-conversion emission in KGd(WO 4 ) 2 single crystals triply-doped with Er 3+ /Yb 3+ /Tm 3+ , Tb 3+ /Yb 3+ /Tm 3+ and Pr 3+ /Yb 3+ /Tm 3+ ions  

NASA Astrophysics Data System (ADS)

Triply-doped single crystals KGd(WO 4) 2:Er 3+/Yb 3+/Tm 3+, KGd(WO 4) 2:Tb 3+/Yb 3+/Tm 3+ and KGd(WO 4) 2:Pr 3+/Yb 3+/Tm 3+ were grown by the Top Seeded Solution Growth (TSSG) method, with an aim of getting efficient up-converted multicolored luminescence, which subsequently can be used for generation of white light. Such an aim determined the choice of the triply doped compounds: excitation of the Yb 3+ ions in the infrared spectral region is followed by red, green and blue emission from other dopants. It was shown that all these systems exhibit multicolor up-conversion fluorescence under 980 nm laser irradiation. Detailed spectroscopic studies of their absorption and luminescence spectra were performed. From the analysis of the dependence of the intensity of fluorescence on the excitation power the conclusion was made about significant role played by the host's conduction band and other possible defects of the KGd(WO 4) 2 crystal lattice in the up-conversion processes.

Kasprowicz, D.; Brik, M. G.; Majchrowski, A.; Michalski, E.; G?uchowski, P.

2011-09-01

13

Solvothermal syntheses, and characterization of [ Ln(en) 4(SbSe 4)] ( Ln=Ce, Pr) and [ Ln(en) 4]SbSe 4·0.5en ( Ln=Eu, Gd, Er, Tm, Yb): The effect of lanthanide contraction on the crystal structures of lanthanide selenidoantimonates(V)  

NASA Astrophysics Data System (ADS)

Two types of lanthanide selenidoantimonates [ Ln(en) 4(SbSe 4)] ( Ln=Ce( 1a), Pr( 1b)) and [ Ln(en) 4]SbSe 4·0.5en ( Ln=Eu( 2a), Gd( 2b), Er( 2c), Tm( 2d), Yb( 2e); en=ethylenediamine) were solvothermally synthesized by reactions of LnCl 3, Sb and Se with the stoichiometric ratio in en solvent at 140 °C. The four-en coordinated lanthanide complex cation [ Ln(en) 4] 3+ formed in situ balances the charge of SbSe 43- anion. In compounds 1a and 1b, the SbSe 43- anion act as a monodentate ligand to coordinate complex [ Ln(en) 4] 3+ and the neutral compound [ Ln(en) 4(SbSe 4)] is formed. The Ln3+ ion has a nine-coordinated environment involving eight N atoms and one Se atom forming a distorted monocapped square antiprism. In 2a-2e the lanthanide(III) ion exists as isolated complex [ Ln(en) 4] 3+, in which the Ln3+ ion is in a bicapped trigonal prism geometry. A systematic investigation of the crystal structures reveals that two types of structural features of these lanthanide selenidoantimonates are related with lanthanides contraction across the lanthanide series. TG curves show that compounds 1a- 1b and 2a- 2e remove their organic components in one and two steps, respectively.

Jia, Dingxian; Zhu, Aimei; Jin, Qinyan; Zhang, Yong; Jiang, Wenqing

2008-09-01

14

Novel Y2O3-codoped Yb/Tm-doped picosecond fiber laser  

NASA Astrophysics Data System (ADS)

We demonstrate the novel picosecond mode-locked Y2O3-codoped Yb/Tm-doped fiber lasers, operating at 1950 nm and producing pulses of up to 1 nJ energy, using a SESAM and an Er-doped pump fiber laser operating at the wavelength 1590 nm or a semiconductor pump laser operating at the wavelength of 1560 nm. We also report on the spectroscopic characterization of these new fibers with various compositions, identifying the optimum one for the maximum Yb/Tm energy transfer, the latter increasing with the increase of the Y concentration. The observed energy transfer between Yb and Tm makes this laser promising also for direct diode-pumping with most advanced and low cost 975 nm diodes, making this laser attractive for compact low cost picosecond Tm-doped fiber laser systems.

Dvoyrin, Vladislav V.; Klimentov, Dmitry; Halder, Arindam; Paul, Mukul C.; Pal, Mrinmay; Bhadra, Shyamal K.; Kir'yanov, Alexander V.; Sorokina, Irina T.

2013-02-01

15

Upconversion emission from Tm 3+:Yb 3+ and Tm 3+:Er 3+:Yb 3+ doped Y 2SiO 5 powders prepared by combustion synthesis  

Microsoft Academic Search

Tm3+:Er3+:Yb3+ doped Y2SiO5 powders were prepared by combustion synthesis with estimated as-prepared weight (wt.) % concentrations of 0.25:0.0:2.0, 0.25:0.5:2.0 and 0.25:1.0:2.0, respectively. Blue (Tm3+: 1G4?3H6), green (Er3+: 4S3\\/2, 2H11\\/2?4I15\\/2) and red (Er3+: 4F9\\/2?4I15\\/2) upconversion (UC) emissions were observed under 975nm infrared diode laser excitation. The UC process took place via energy transfer from Yb3+ to Er3+ and Tm3+ ions. The

Nikifor Rakov; Glauco S. Maciel; R. B. Guimarães; I. C. S. Carvalho

2010-01-01

16

Complexation of trivalent rare earth elements (Ce, Eu, Gd, Tb, Yb) by carbonate ions  

Microsoft Academic Search

Carbonate stability constants for five rare earth elements (Ce[sup 3+], Eu[sup 3+], Gd[sup 3+], Tb[sup 3+], and Yb[sup 3+]) have been determined at t = 25[degrees]C and 0.70 [plus minus] 0.02 M ionic strength through solvent exchange techniques. Estimated stability constants for Ce, Eu, and Yb are in close agreement with previous work. Analyses using Gd and Tb provide the

Jong Hyeon Lee; R. H. Byrne

1993-01-01

17

Non-ionic contributions to the electric-field gradient at $^{181}$Ta and $^{111}$Cd impurity sites in R$_2$O$_3$ (R= Sc, In, Lu, Yb, Tm, Er, Y, Ho, Dy, Gd, Eu, Sm) bixbyites  

E-print Network

The time-differential perturbed-angular-correlation (TDPAC) technique was applied to the study of the internal electric-field gradient (EFG) in Eu- and Ho-sesquioxides in their cubic bixbyite phases. The results, as well as previous characterizations of the EFG at $^{181}$Ta sites in oxides with the bixbyite structure, were compared to those obtained in experiments using $^{111}$Cd as probe, and to point-charge model and {\\it ab initio} results calculations for the EFG tensor at impurity sites in binary oxides. These studies provide quantitative information about electronic processes and the structural relaxations induced by the presence of impurity probes in the host lattices, and confirm the existence of nonionic contributions to the EFG in these systems. Our FP-LAPW calculations show that this nonionic contribution to the EFG is the dominating one, and that it is originated in the population of {\\it p} states (5{\\it p} in the case of Cd, 6{\\it p} for Ta).

Leonardo A. Errico; Mario Rentería; Aníbal G. Bibiloni; Kristian Freitag

2004-03-01

18

Spectroscopic analysis of Eu3+ -and Eu3+:Yb3+-doped yttrium silicate crystalline powders prepared by combustion synthesis  

Microsoft Academic Search

Yttrium silicate powders doped with Eu3+ and codoped with Eu3+ and Yb3+ were prepared by combustion synthesis. The x-ray powder diffraction data showed the presence of Y2SiO5 and Y2Si2O7 crystalline phases. Singly doped (1 wt %) sample illuminated with ultraviolet light (lambda=256 nm) showed the characteristic red luminescence corresponding to 5D0-->7FJ transitions of Eu3+. The Judd-Ofelt intensity parameters were calculated

Nikifor Rakov; Dayanne F. Amaral; Glauco S. Maciel

2010-01-01

19

Spectroscopic analysis of Eu3+ -and Eu3+:Yb3+-doped yttrium silicate crystalline powders prepared by combustion synthesis  

Microsoft Academic Search

Yttrium silicate powders doped with Eu3+ and codoped with Eu3+ and Yb3+ were prepared by combustion synthesis. The x-ray powder diffraction data showed the presence of Y2SiO5 and Y2Si2O7 crystalline phases. Singly doped (1 wt %) sample illuminated with ultraviolet light (?=256 nm) showed the characteristic red luminescence corresponding to 5D0?7FJ transitions of Eu3+. The Judd–Ofelt intensity parameters were calculated

Nikifor Rakov; Dayanne F. Amaral; Renato B. Guimarães; Glauco S. Maciel

2010-01-01

20

Near-infrared luminescence from Y2O3:Eu3+, Yb3+ prepared by sol-gel method.  

PubMed

Eu3+ and Yb3+ codoped Y2O3 phosphors were synthesized by the sol-gel method. The phosphors possess absorption in the region of 300-550 nm, exhibiting an intense NIR emission of Yb3+ around 1000 nm, which is suitable for matching the maximum spectral response of c-Si solar cells. The optimum composition of Eu3+ and Yb3+ codoped Y2O3 was (Y1.94Yb0.04Eu0.02)2O3. It is observed that two-step energy transfer occurs from the 5D2 level of Eu3+ situated around (466 nm) exciting two neighboring Yb3+ ions to the 2F5/2 level (1000 nm). The down-conversion material based on Eu(3+)- Yb3+ couple may have great potential applications in c-Si solar cells to enhance their photovoltaic conversion efficiency via spectral modification. PMID:24738417

Xie, Ying; Xiao, Lin J; Yan, Feng Q; Chen, Yong J; Li, Wen Z; Geng, Xiu J

2014-06-01

21

Multicolor upconversion emission and energy transfer mechanism in Er3+/Tm3+/Yb3+ codoped tellurite glasses  

NASA Astrophysics Data System (ADS)

A novel Er3+, Tm3+ and Yb3+ codoped tellurite glasses with composition of TeO2-Bi2O3-ZnO-Na2O was prepared by conventional melt-quenching technique to realize the multicolor upconversion (UC) emissions. The absorption spectrum, UC emission spectrum, Raman spectrum, X-ray diffraction (XRD) and differential scanning calorimeter (DSC) curves were measured to characterize the prepared glass samples. Under the excitation of 980 nm laser diode (LD), bright multicolor luminescence composed of red, green and/or blue UC emissions corresponding to the transitions 4F9/2?4I15/2, 2H11/2(4S3/2)?4I15/2 of Er3+ and 1G4?3H6 of Tm3+ were observed in the Er3+/Yb3+, Tm3+/Yb3+ and Er3+/Tm3+/Yb3+ codoped glass samples, which were mainly attributed to the successive energy transfers from Yb3+ to Er3+ and Tm3+, respectively. The energy transfer mechanisms from the Yb3+:2F5/2 level to Er3+:4I11/2 and Tm3+:3H5 levels were further investigated by quantitatively calculating the energy transfer micro-parameters and phonon contribution ratios. Meanwhile, the difference (?T=Tx-Tg) between the glass crystallization onset temperature (Tx) and the transition temperature (Tg) which increase slightly with rare-earth (RE) doped concentration, was larger than 140 °C for all glass samples. Furthermore, the amorphous nature of glass structure was demonstrated by the measured XRD curves. The excellent thermal stability and multicolor luminescent characteristic indicate that the present investigated Er3+/Tm3+/Yb3+ codoped tellurite glasses could be used in the fields of solid state multicolor displays and other luminescent devices.

Peng, Shengxi; Yang, Fengjing; Wu, Libo; Qi, Yawei; Zheng, Shichao; Yin, Dandan; Wang, Xunsi; Zhou, Yaxun

2014-11-01

22

Buffer gas loaded magneto-optical traps for Yb, Tm, Er and Ho  

NASA Astrophysics Data System (ADS)

Direct loading of lanthanide atoms into magneto-optical traps (MOTs) from a very slow cryogenic buffer gas beam source is achieved, without the need for laser slowing. The beam source has an average forward velocity of 60-70\\;m\\;{{s}^{-1}} and a velocity half-width of \\sim 35\\;m\\;{{s}^{-1}}, which allows for direct MOT loading of Yb, Tm, Er and Ho. Residual helium background gas originating from the beam results in a maximum trap lifetime of about 80 ms (with Yb). The addition of a single-frequency slowing laser applied to the Yb in the buffer gas beam increases the number of trapped Yb atoms to 1.3\\left( 0.7 \\right)\\times {{10}^{8}} with a loading rate of 2.0\\left( 1.0 \\right)\\times {{10}^{10}}\\;atoms\\;{{s}^{-1}}. Decay to metastable states is observed for all trapped species and decay rates are measured. Extension of this approach to the loading of molecules into a MOT is discussed.

Hemmerling, Boerge; Drayna, Garrett K.; Chae, Eunmi; Ravi, Aakash; Doyle, John M.

2014-06-01

23

Multicolor upconversion emission from Tm3++Ho3++Yb3+ codoped tellurite glass on NIR excitations  

NASA Astrophysics Data System (ADS)

Multicolor emission has been produced using 798 nm and 980 nm laser excitation in a Tm3++Ho3++Yb3+ codoped tellurite based glass. This glass generates simultaneously red, green and blue (RGB) emission on 798 nm excitation. Multicolor emission thus obtained was tuned to white luminescence by adjusting the Ho3+ ion concentration. There is a close match between the calculated color coordinate for the white luminescence obtained here and the point of equal energy which represents white in the 1931 CIE chromaticity diagram. The 980 nm excitation of the same sample on the other hand gives intense green and red emission and the glass appears greenish.

Giri, N. K.; Rai, D. K.; Rai, S. B.

2008-06-01

24

Synthesis, persistent luminescence, and thermoluminescence properties of yellow Sr3SiO5:Eu2+,RE3+ (RE=Ce, Nd, Dy, Ho, Er, Tm, Yb) and orange-red Sr(3-x)Ba(x)SiO5:Eu2+, Dy3+ phosphor.  

PubMed

Sunlight-excitable orange or red persistent oxide phosphors with excellent performance are still in great need. Herein, an intense orange-red Sr3-xBaxSiO5:Eu(2+),Dy(3+) persistent luminescence phosphor was successfully developed by a two-step design strategy. The XRD patterns, photoluminescence excitation and emission spectra, and the thermoluminescence spectra were investigated in detail. By adding non-equivalent trivalent rare earth co-dopants to introduce foreign trapping centers, the persistent luminescence performance of Eu(2+) in Sr3SiO5 was significantly modified. The yellow persistent emission intensity of Eu(2+) was greatly enhanced by a factor of 4.5 in Sr3SiO5:Eu(2+),Nd(3+) compared with the previously reported Sr3SiO5:Eu(2+), Dy(3+). Furthermore, Sr ions were replaced with equivalent Ba to give Sr3-xBaxSiO5 :Eu(2+),Dy(3+) phosphor, which shows yellow-to-orange-red tunable persistent emissions from ?=570 to 591?nm as x is increased from 0 to 0.6. Additionally, the persistent emission intensity of Eu(2+) is significantly improved by a factor of 2.7 in Sr3-xBaxSiO5 :Eu(2+),Dy(3+) (x=0.2) compared with Sr3SiO5 :Eu(2+),Dy(3+). A possible mechanism for enhanced and tunable persistent luminescence behavior of Eu(2+) in Sr3-xBaxSiO5:Eu(2+),RE(3+) (RE=rare earth) is also proposed and discussed. PMID:24203579

Li, Ye; Li, Baohong; Ni, Chenchen; Yuan, Shuxia; Wang, Jing; Tang, Qiang; Su, Qiang

2014-02-01

25

Emission properties of hydrothermal Yb3 + , Er3 + and Yb3 + , Tm3 + -codoped Lu2O3 nanorods: upconversion, cathodoluminescence and assessment of waveguide behavior  

NASA Astrophysics Data System (ADS)

Yb3 + and Ln3 + (Ln3 + = Er3 + or Tm3 + ) codoped Lu2O3 nanorods with cubic Ia\\bar 3 symmetry have been prepared by low temperature hydrothermal procedures, and their luminescence properties and waveguide behavior analyzed by means of scanning near-field optical microscopy (SNOM). Room temperature upconversion (UC) under excitation at 980 nm and cathodoluminescence (CL) spectra were studied as a function of the Yb + concentration in the prepared nanorods. UC spectra revealed the strong development of {Er}^{3+}\\,^{4} {F}_{9/2}\\to {}^4 {I}_{15/2} (red) and {Tm}^{3+}\\,{}^{1} {G}_{4} \\to {}^{3} {H}_{6} (blue) bands, which became the pre-eminent and even unique emissions for corresponding nanorods with the higher Yb3 + concentration. Favored by the presence of large phonons in current nanorods, UC mechanisms that privilege the population of 4F9/2 and 1G4 emitting levels through phonon-assisted energy transfer and non-radiative relaxations account for these observed UC luminescence features. CL spectra show much more moderate development of the intensity ratio between the {Er}^{3+}\\, {}^{4} {F}_{9/2} \\to {}^4 {I}_{15/2} (red) and 2H11/2, ^{4} {S}_{3/2}\\to {}^{4} {I}_{15/2} (green) emissions with the increase in the Yb3 + content, while for Yb3 + , Tm3 + -codoped Lu2O3 nanorods the dominant CL emission is {Tm}^{3+}\\,{}^{1} {D}_{2}\\to {}^{3} {F}_{4} (deep-blue). Uniform light emission along Yb3 + , Er3 + -codoped Lu2O3 rods has been observed by using SNOM photoluminescence images; however, the rods seem to be too thin for propagation of light.

Barrera, Elixir William; Cinta Pujol, María; Díaz, Francesc; Choi, Soo Bong; Rotermund, Fabian; Park, Kyung Ho; Jeong, Mun Seok; Cascales, Concepción

2011-02-01

26

Emission properties of hydrothermal Yb(3+), Er(3+) and Yb(3+), Tm(3+)-codoped Lu2O3 nanorods: upconversion, cathodoluminescence and assessment of waveguide behavior.  

PubMed

Yb(3+) and Ln(3+) (Ln(3+) = Er(3+) or Tm(3+)) codoped Lu(2)O(3) nanorods with cubic Ia3 symmetry have been prepared by low temperature hydrothermal procedures, and their luminescence properties and waveguide behavior analyzed by means of scanning near-field optical microscopy (SNOM). Room temperature upconversion (UC) under excitation at 980 nm and cathodoluminescence (CL) spectra were studied as a function of the Yb(+) concentration in the prepared nanorods. UC spectra revealed the strong development of Er(3+) (4)F(9/2) ? (4)I(15/2) (red) and Tm(3+) (1)G(4) ? (3)H(6) (blue) bands, which became the pre-eminent and even unique emissions for corresponding nanorods with the higher Yb(3+) concentration. Favored by the presence of large phonons in current nanorods, UC mechanisms that privilege the population of (4)F(9/2) and (1)G(4) emitting levels through phonon-assisted energy transfer and non-radiative relaxations account for these observed UC luminescence features. CL spectra show much more moderate development of the intensity ratio between the Er(3+) (4)F(9/2) ? (4)I(15/2) (red) and (2)H(11/2), (4)S(3/2) ? (4)I(15/2) (green) emissions with the increase in the Yb(3+) content, while for Yb(3+), Tm(3+)-codoped Lu(2)O(3) nanorods the dominant CL emission is Tm(3+) (1)D(2) ? (3)F(4) (deep-blue). Uniform light emission along Yb(3+), Er(3+)-codoped Lu(2)O(3) rods has been observed by using SNOM photoluminescence images; however, the rods seem to be too thin for propagation of light. PMID:21233550

Barrera, Elixir William; Pujol, María Cinta; Díaz, Francesc; Choi, Soo Bong; Rotermund, Fabian; Park, Kyung Ho; Jeong, Mun Seok; Cascales, Concepción

2011-02-18

27

Sol-gel synthesis and characterization of sub-microsized lanthanide (Ho, Tm, Yb, Lu) aluminium garnets  

NASA Astrophysics Data System (ADS)

Sub-microsized and nanosized holmium aluminium garnet (Ho 3Al 5O 12, HoAG), thulium aluminium garnet (Tm 3Al 5O 12, TmAG), ytterbium aluminium garnet (Yb 3Al 5O 12, YbAG) and lutetium aluminium garnet (Lu 3Al 5O 12, LuAG) powders were prepared by a simple aqueous sol-gel method using aluminium nitrate nonahydrate, lutetium oxide, thulium oxide, holmium oxide and ytterbium oxide as starting materials. Ethane-1,2-diol was used as complexing agent. The powder X-ray diffraction (XRD) patterns of the specimens sintered at 1000 °C revealed the formation of monophasic HoAG, TmAG, YbAG, and LuAG. The phase composition of the samples was also characterized by infrared (IR) spectroscopy. Microstructural features of the polycrystalline garnets were studied by scanning electron microscopy (SEM).

Dubnikova, N.; Garskaite, E.; Beganskiene, A.; Kareiva, A.

2011-06-01

28

Water Research 39 (2005) 239247 Biosorption of La, Eu and Yb using Sargassum biomass  

E-print Network

Water Research 39 (2005) 239­247 Biosorption of La, Eu and Yb using Sargassum biomass Vivian Diniz-loaded biomass was studied. The ion exchange sorption mechanism was confirmed by the release of calcium ions from the biomass that matched the total number of metal and protons removed from the solution. The metal binding

Volesky, Bohumil

29

Synthesis, structure, magnetism, and optical properties of theordered mixed-lanthanide sulfides gamma-LnLn'S3 (Ln=La, Ce; Ln'=Er, Tm,Yb)  

Microsoft Academic Search

γ-LnLnâ²Sâ (Ln = La, Ce; Lnâ² = Er, Tm, Yb) have been prepared as dark red to black single crystals by the reaction of the respective lanthanides with sulfur in a SbâSâ flux at 1000 C. This isotypic series of compounds adopts a layered structure that consists of the smaller lanthanides (Er, Tm, and Yb) bound by sulfide in six-

G. B. Jin; E. S. Choi; R. P. Guertin; J. S. Brooks; T. H. Bray; C. H. Booth; T. E. Albrecht-Schmitt

2006-01-01

30

Bright white upconversion luminescence from Er 3+-Tm 3+-Yb 3+ doped CaSnO 3 powders  

NASA Astrophysics Data System (ADS)

Bright white upconversion luminescence from Er 3+-Tm 3+-Yb 3+ doped CaSnO 3 powders is obtained under the diode laser excitation of 980 nm. It is composed of three primary colors of red, green and blue emissions, which originate from the transitions of 4F 9/2 ? 4I 15/2, ( 2H 11/2, 4S 3/2) ? 4I 15/2 of Er 3+ ions and 1G 4 ? 3H 6 of Tm 3+ ions, respectively. The efficient upconversion emission is attributed to the energy transfer between Yb 3+ and Er 3+ or Tm 3+ions. Moreover, it is observed that Tm 3+ acts as the quenching center for the green upconversion luminescence from Er 3+ ions, and the sensitizer for the red and blue luminescence when the Tm 3+ doping content is less than 0.3 mol%. This is interpreted in terms of the efficient energy transfer between Tm 3+ and Er 3+ ions. The calculated color coordinates fall within the white region in the standard 1931 CIE chromaticity diagram, indicating the potential applications of Er 3+-Tm 3+-Yb 3+ doped CaSnO 3 in the field of displaying and lasers, etc.

Pang, X. L.; Jia, C. H.; Li, G. Q.; Zhang, W. F.

2011-11-01

31

Application of doped rare-earth oxide TiO2:(Tm3+, Yb3+) in dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Tm3+ and Yb3+ are codoped into TiO2 film in a dye-sensitized solar cell (DSSC). The emission and excitation spectra of TiO2:(Tm3+, Yb3+) power shows that the rare-earth ions possess up-conversion luminescence function, which results in harvesting more incident light and increasing photocurrent for the DSSC. On the other hand, owing to the p-type doping effect by Tm3+ and Yb3+, the photovoltage of the DSSC is enhanced. Under a simulated solar light irradiation of 100 mW·cm-2, a DSSC containing Tm3+/Yb3+ achieves a conversion efficiency of 7.05 %, which is increased by 10.0% compared with a DSSC lacking Tm3+/Yb3+.

Xie, Guixiang; Wei, Yuelin; Fan, Leqing; Wu, Jihuai

2012-01-01

32

Effect of Metal Coating on NaYF4:Yb3+,Tm 3+ Upconversion Nanoparticles  

NASA Astrophysics Data System (ADS)

Upconversion is the process in which two or more low-energy photons are absorbed and emitted as one high-energy photon. This research reports on the effect of layer-by-layer polyelectrolytes and silver coating on hexagonal NaYF4:Yb3+,Tm3+ in an attempt to enhance the upconversion intensity. The synthesized upconversion nanoparticles were separated into two, ˜140 nm and a mixture of two populations, ˜250 nm and ˜25 nm. The former case observed enhancement, when silver coated on the upconversion nanoparticles using hydroquinone as the reducing agent, with no layers and with several layers (three, four and five) of polyelectrolytes. The size (140 nm) and morphology of the hexagonal NaYF4:Yb 3+,Tm3+ were similar. The enhancement was confirmed when sodium cyanide was added to remove the silver coating from the sample resulting in a decrease in the upconversion intensity. Quenching was observed in the latter case, when silver coating was unsuccessful and that there are two populations of upconversion nanoparticles (large ˜250 nm and small ˜25 nm).

Alazemi, Abdulrahman

33

Y2O3:Tm,Yb nanophosphors for correlative upconversion luminescence and cathodoluminescence imaging.  

PubMed

We present a phosphor nanoparticle that shows both upconversion luminescence (UCL) and cathodoluminescence (CL). With this particle, low-autofluorescence, deep-tissue and wide-field fluorescence imaging can be achieved with nanometer-order high-spatial-resolution imaging. We synthesized Y2O3:Tm,Yb nanophosphors that emit visible and near-infrared UCL under 980nm irradiation and blue CL via electron beam excitation. The phosphors were applied to fluorescent imaging of HeLa cells. The photostability of the phosphors was superior to that of a conventional organic dye. We show that after uptake by HeLa cells, the particles can be imaged with SEM and CL contrast in a cellular section. This indicates that correlative UCL and CL imaging of biological samples could be realized. PMID:25146422

Fukushima, Shoichiro; Furukawa, Taichi; Niioka, Hirohiko; Ichimiya, Masayoshi; Miyake, Jun; Ashida, Masaaki; Araki, Tsutomu; Hashimoto, Mamoru

2014-12-01

34

Broadband near-infrared downconversion luminescence in Eu2+-Yb3+ codoped Ca9Y(PO4)7  

NASA Astrophysics Data System (ADS)

An efficient broadband near-infrared (NIR) quantum cutting was demonstrated in Eu2+-Yb3+ codoped Ca9Y(PO4)7 phosphor. Upon excitation of Eu2+ ions to the 4f65d1 level with an ultraviolet photon at 322 nm, emissions of two NIR photons at 983 nm of Yb3+were achieved. The dependences of the visible and NIR emissions, the decay lifetime, the energy transfer efficiency (ETE), and the quantum efficiency (QE) on the Yb3+ doping content were investigated in detail. The results indicated that the maximum ETE and the corresponding downconversion QE can reach between 80% and 179%, respectively.

Sun, Jiayue; Zhou, Wei; Sun, Yining; Zeng, Junhui

2013-06-01

35

Optical transitions of Tm3+ in oxyfluoride glasses and compositional and thermal effect on upconversion luminescence of Tm3+/Yb3+-codoped oxyfluoride glasses  

NASA Astrophysics Data System (ADS)

Optical properties of Tm3+-doped SiO2-BaF2-ZnF2 glasses have been investigated on the basis of the Judd-Ofelt theory. Judd-Ofelt intensity parameters, radiative transition probabilities, fluorescence branching ratios and radiative lifetimes have been calculated for different glass compositions. Upconversion emissions were observed in Tm3+/Yb3+-codoped SiO2-BaF2-ZnF2 glasses under 980 nm excitation. The effects of composition, concentration of the doping ions, temperature, and excitation pump power on the upconversion emissions were also systematically studied.

Feng, Li; Wu, Yinsu; Liu, Zhuo; Guo, Tao

2014-01-01

36

Synthesis and photoluminescence properties of heteroleptic Eu 3+, Tb 3+ and Tm 3+ complexes  

Microsoft Academic Search

Five Eu(III), four Tb(III) and two Tm(III) multichromophoric complexes (1-Eu, 1-Tb, 2-Eu, 3-Eu, 3-Tb, 3-Tm, 4-Tb, 4-Tm, 5-Eu, 6-Eu and 6-Tb; where 1=tris[dibenzoylmethanido] (4?-chloro-2,2?:6?,2??-terpyridine), 2=tris[dibenzoylmethanido] (4?-(9H-carbazol-9yl)-2,2?:6?,2??-terpyridine), 3=tris(1,1,1,5,5,5-hexafluoroacetylacetonato), 4=tris[1,1,1,5,5,5-hexafluoroacetylacetonato] (tripyridin-2-ylamine), 5=tris[dibenzoylmethanido][N-(4-(9H-carbazol-9-yl)butyl)-N-(dipyridin-2-yl)amine] and 6=tris[dibenzoylmethanido][N-(6-(9H-carbazol-9-yl)hexyl)-N-(dipyridin-2-yl)amine]) emitting in the blue (Tm), green (Tb) and red (Eu) spectral regions, have been synthesized and characterized. The complexes involve five different coordinating (2,2?:6?,2??-terpyridine (terpy); dibenzoylmethane (dbm); 1,1,1,5,5,5-hexafluoroacetylacetonato

Gianluca Accorsi; Nicola Armaroli; François Cardinali; Dong Wang; Youxuan Zheng

2009-01-01

37

Spectroscopic analysis of Eu{sup 3+} -and Eu{sup 3+}:Yb{sup 3+}-doped yttrium silicate crystalline powders prepared by combustion synthesis  

Microsoft Academic Search

Yttrium silicate powders doped with Eu{sup 3+} and codoped with Eu{sup 3+} and Yb{sup 3+} were prepared by combustion synthesis. The x-ray powder diffraction data showed the presence of YSiO and YSiO crystalline phases. Singly doped (1 wt %) sample illuminated with ultraviolet light (=256 nm) showed the characteristic red luminescence corresponding to DF{sub J} transitions of Eu{sup 3+}. The

Nikifor Rakov; Dayanne F. Amaral; Renato B. Guimaraes; Glauco S. Maciel

2010-01-01

38

Structural properties in RFe2O4 compounds (R=Tm, Yb, and Lu)  

NASA Astrophysics Data System (ADS)

We report a complete characterization of the crystal structure between 400 and 80 K for RFe2O4 (R = Rm, Yb, and Lu) compounds using high resolution x-ray synchrotron powder diffraction. The three samples have a hexagonal structure (space group R3¯m) characterized by a sequence of double layers of mixed valence iron and oxygen atoms forming two-dimensional triangular layers separated by a single R-O layer along the c axis. This structure is stable down to 80 K for TmFe2O4 and YbFe2O4 though a sudden expansion in the c axis is observed at around 300 K coupled to a variation in the electrical properties. However, LuFe2O4 exhibits two structural transitions upon cooling. The splitting of some reflections and the occurrence of superstructure peaks below 320 K reveal a structural phase transition. The unit cell is monoclinic (space group C2/m), and there are four nonequivalent Fe sites with a maximum charge disproportionation of 0.5 e. The hexagonal to monoclinic transition is characterized by a sudden expansion of the c axis on cooling, and it seems to be driven by the condensation of Y2 modes. At lower temperatures (˜170 K) additional splitting of several peaks indicate that the unit cell is no longer monoclinic but triclinic (space group P1¯). This transition is characterized by a contraction of the monoclinic ab plane, while the c axis remains almost unchanged. There are six nonequivalent Fe sites in the triclinic cell, and the charge disproportionation magnitude is little affected.

Blasco, J.; Lafuerza, S.; García, J.; Subías, G.

2014-09-01

39

Vacuum ultraviolet and near-infrared excited luminescence properties of Ca 3(PO 4) 2: RE3+, Na + ( RE=Tb, Yb, Er, Tm, and Ho)  

NASA Astrophysics Data System (ADS)

Tb 3+, Yb 3+, Tm 3+, Er 3+, and Ho 3+ doped Ca 3(PO 4) 2 were synthesized by solid-state reaction, and their luminescence properties were studied by spectra techniques. Tb 3+-doped samples can exhibit intense green emission under VUV excitation, and the brightness for the optimal Tb 3+ content is comparable with that of the commercial Zn 2SiO 4:Mn 2+ green phosphor. Under near-infrared laser excitation, the upconversion luminescence spectra of Yb 3+, Tm 3+, Er 3+, and Ho 3+ doped samples demonstrate that the red, green, and blue tricolored fluorescence could be obtained by codoping Yb 3+-Ho 3+, Yb 3+-Er 3+, and Yb 3+-Tm 3+ in Ca 3(PO 4) 2, respectively. Good white upconversion emission with CIE chromaticity coordinates (0.358, 0.362) is achieved by quadri-doping Yb 3+-Tm 3+-Er 3+-Ho 3+ in Ca 3(PO 4) 2, in which the cross-relaxation process between Er 3+ and Tm 3+, producing the 1D2- 3F4 transition of Tm 3+, is found. The upconversion mechanisms are elucidated through the laser power dependence of the upconverted emissions and the energy level diagrams.

Zhang, Jia; Wang, Yuhua; Guo, Linna; Zhang, Feng; Wen, Yan; Liu, Bitao; Huang, Yan

2011-08-01

40

SrAl4O7:Tm3+\\/Yb3+ nanocrystalline blue phosphor: structural, thermal and optical properties  

Microsoft Academic Search

Strontium aluminate (SrAl4O7) nanophosphor codoped with Tm3+-Yb3+ has been synthesized through the combustion route using urea as the reducing agent. Structural, thermal and optical characterizations have been carried out. Heat treatment of the samples shows a change in the crystallite phases and the relative luminescence intensities for the different bands. The nanocrystalline particles in the as-synthesized sample seem to arrange

N. K. Giri; S. K. Singh; D. K. Rai; S. B. Rai

2010-01-01

41

SrAl 4 O 7 :Tm 3+ \\/Yb 3+ nanocrystalline blue phosphor: structural, thermal and optical properties  

Microsoft Academic Search

Strontium aluminate (SrAl4O7) nanophosphor codoped with Tm3+–Yb3+ has been synthesized through the combustion route using urea as the reducing agent. Structural, thermal and optical characterizations\\u000a have been carried out. Heat treatment of the samples shows a change in the crystallite phases and the relative luminescence\\u000a intensities for the different bands. The nanocrystalline particles in the as-synthesized sample seem to arrange

N. K. Giri; S. K. Singh; D. K. Rai; S. B. Rai

2010-01-01

42

Intense white light emission in Tm3+/Er3+/Yb3+ co-doped Y2O3-ZnO nano-composite  

NASA Astrophysics Data System (ADS)

The Tm3+/Er3+/Yb3+ co-doped Y2O3-ZnO nano-composite is synthesized using the solution combustion technique. The structural morphology is monitored using x-ray diffraction, transmission electron microscopy and scanning electron microscopy. The Yb3+/Tm3+ co-doped nano-phosphor emits intense blue as well as weak red emissions, while Yb3+/Er3+ co-doped nano-phosphor emits strong green along with red emissions on excitation with 976 nm laser. Joining these together (i.e. Tm3+/Er3+/Yb3+ co-doped phosphor) give very strong white light, which is further verified by CIE coordinates (0.32, 0.36). The addition of ZnO with Y2O3 phosphor gives further enhancement in the intensity of white light. The possible reason for this enhancement is the removal of optical quenching sites.

Yadav, R. S.; Verma, R. K.; Rai, S. B.

2013-07-01

43

Effect of Ag nanoparticles on the radiative properties of tellurite glasses doped with Er3+, Yb3+ and Tm3+ ions  

NASA Astrophysics Data System (ADS)

The present work is devoted to the characterization of the thermal and spectroscopic properties of tellurite glasses, codoped with Er3+, Yb3+ and Tm3+ rare-earth ions and silver nanoparticles (NPs). The techniques used for this investigation were UV-visible and infrared absorption, time-resolved luminescence and thermal lens. Time-resolved luminescence studies indicate efficient Yb3+ ? Er3+ and Yb3+ ? Tm3+ energy transfers and intense Er3+ and Tm3+ mid-infrared emissions around 1550 nm and 1860 nm, respectively. The presence NPs is found to increase the thermal diffusivity of the materials and to shorten the mid-infrared emission lifetime of both the Er3+ and Tm3+ ions.

Silva, G. H.; Holgado, D. P. A.; Anjos, V.; Bell, M. J. V.; Kassab, L. R. P.; Amâncio, C. T.; Moncorgè, Richard

2014-11-01

44

Infrared-to-visible up-conversion luminescence and energy transfer of RE3+/Yb3+(RE = Ho, Tm) co-doped SrIn2O4  

NASA Astrophysics Data System (ADS)

Near-infrared excited up-conversion phosphors of RE3+/Yb3+(RE = Ho, Tm) co-doped SrIn2O4 were synthesized by a solid-state reaction method. X-ray diffraction analysis revealed the phase composition of those samples, and the up-conversion spectroscopic properties were studied in terms of up-conversion emission spectra. Under 980 nm near-infrared laser excitation, strong green emission with the peak at 546 nm was observed in SrIn2O4: Ho3+/Yb3+, which can be assigned to the characteristic 5S2(5F4) ? 5I8 transition of Ho3+. Furthermore, SrIn2O4: Tm3+/Yb3+ showed bright blue emission with the peak at 486 nm, which is associated with the 1G4 ? 3H6 transition of Tm3+. The UC power studies indicated that the luminescence of SrIn2O4: Ho3+/Yb3+ and SrIn2O4: Tm3+/Yb3+ are attributed to two-photon and three-photon process, respectively. The possible UC luminescence mechanism and energy transfer in SrIn2O4: RE3+/Yb3+ were discussed.

Guan, Ming; Zheng, Hong; Mei, Lefu; Huang, Zhaohui; Yang, Tao; Fang, Minghao; Liu, Yangai

2014-11-01

45

Anisotropy of optical properties of hexagonal RMnO3 Manganites ( R = Ho, Er, Tm, Yb)  

NASA Astrophysics Data System (ADS)

The evolution of real and imaginary parts of the complex permittivity of hexagonal single crystals of RMnO3 manganites ( R = Ho, Er, Tm, Yb) differing in the radius of rare-earth ion r R has been studied using spectroscopic ellipsometry in the range of 0.5-5.0 eV at room temperature. Spectra of dielectric functions show a strong polarization dependence. The optical-absorption edge for polarization E ? c is determined by the intense narrow peak at 1.6 eV, whereas for polarization E ? c, the peak is shifted toward high energies by 0.15-0.20 eV and its intensity is suppressed greatly. It has been shown that, when r R decreases, the energy position of the intense peak at 1.6 eV in the spectrum of the imaginary part of the dielectric function for polarization E ? c shifts toward low energies by no more than 0.1 eV, which reflects changes in the local surroundings of the Mn3+ ion. For the both polarizations, a broad absorption band with the center at 2.4 eV has been revealed; the band was detected earlier in the antiferromagnetic phase in nonlinear spectra upon the optical generation of the second harmonic. Spectra of permittivity have been analyzed within available concepts on the electronic structure of hexagonal RMnO3 compounds and have been compared with corresponding spectra of previously studied orthorhombic RMnO3 compounds.

Makhnev, A. A.; Nomerovannaya, L. V.

2013-11-01

46

MOLTEN SALT SYNTHESIS OF YF3:Yb3+/Ln3+(Ln = Er3+, Tm3+) MICROSHEETS WITH MULTICOLOR UPCONVERSION LUMINESCENCE  

NASA Astrophysics Data System (ADS)

In this paper, highly crystalline YF3:Yb3+/Ln3+(Ln = Er3+, Tm3+) microsheets were successfully synthesized by a surfactant-free molten salt method for the first time. The results indicated that the as-obtained samples belonged to orthorhombic system and exhibited microsheets morphology with side lengths of 30 to 80 ?m and wall thickness from 1 to 1.5 ?m. By changing the dopant's species (Ln3+), multicolor (yellow and blue) upconversion emission can be observed in YF3:Yb3+/Ln3+ microsheets under 980 nm laser diode (LD) excitation. The upconversion mechanisms in co-doping YF3 samples were analyzed in detail based on the emission spectra. Importantly, this approach not only proposes a new alternative in synthesizing such materials, but also opens the possibility to meet the increasing commercial demand.

Ding, Mingye; Lu, Chunhua; Cao, Linhai; Ni, Yaru; Xu, Zhongzi

2013-12-01

47

Up-conversion white light of Tm 3+/Er 3+/Yb 3+ tri-doped CaF 2 phosphors  

NASA Astrophysics Data System (ADS)

Tm 3+/Er 3+/Yb 3+ tri-doped CaF 2 phosphors were synthesized using a hydrothermal method. The phosphors were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and up-conversion (UC) emission spectra. After annealing, the phosphors emitted white light under a 980 nm continuous wave diode laser (CW LD 2 W) excitation. As the excitation power density changed in the range of 20-260 W/cm 2, the chromaticity coordinates of the UC light of the phosphor Ca 0.885Tm 0.005Er 0.01Yb 0.1F 2 fell well in the white region of the 1931 CIE diagram. For the proportion of red, green and blue (RGB) in white light is strict, key factors for achieving UC white light, such as host materials, rare earth ions doping concentrations, annealing temperatures, as well as the excitation power densities, were investigated and discussed.

Cao, Chunyan; Qin, Weiping; Zhang, Jisen; Wang, Yan; Wang, Guofeng; Wei, Guodong; Zhu, Peifen; Wang, Lili; Jin, Longzhen

2008-03-01

48

Hall and transverse even effects in the vicinity of a quantum critical point in Tm{sub 1-x}Yb{sub x}B{sub 12}  

SciTech Connect

The angular, temperature, and magnetic field dependences of the resistance recorded in the Hall effect geometry are studied for the rare-earth dodecaboride Tm{sub 1-x}Yb{sub x}B{sub 12} solid solutions where the metal-insulator and antiferromagnetic-paramagnetic phase transitions are observed in the vicinity of the quantum critical point x{sub c} Almost-Equal-To 0.3. The measurements performed on high-quality single crystals in the temperature range 1.9-300 K for the first time have revealed the appearance of the second harmonic contribution, a transverse even effect in these fcc compounds near the quantum critical point. This contribution a is found to increase drastically both under the Tm-to-ytterbium substitution in the range x > x{sub c} and with an increase in the external magnetic field. Moreover, as the Yb concentration x increases, a negative peak of a significant amplitude appears on the temperature dependences of the Hall coefficient R{sub H}(T) for the Tm{sup 1-x}Yb{sub x}B{sub 12} compounds, in contrast to the invariable behavior R{sub H}(T) Almost-Equal-To const found for TmB{sub 12}. The complicated activation-type behavior of the Hall coefficient is observed at intermediate temperatures for x {>=} 0.5 with activation energies E{sub g}/k{sub B} Almost-Equal-To 200 K and E{sub a}/k{sub B} 55-75 K, and the sign inversion of R{sub H}(T) is detected at liquid-helium temperatures in the coherent regime. Renormalization effects in the electron density of states induced by variation of the Yb concentration are analyzed. The anomalies of the charge transport in Tm{sub 1-x}Yb{sub x}B{sub 12} solid solutions in various regimes (charge gap formation, intra-gap many-body resonance, and coherent regime) are discussed in detail and the results are interpreted in terms of the electron phase separation effects in combination with the formation of nanosize clusters of rare earth ions in the cage-glass state of the studied dodecaborides. The data obtained allow concluding that the emergence of Yb-Yb dimers in the Tm{sub 1-x}Yb{sub x}B{sub 12} cage-glass matrix is the origin of the metal-insulator transition observed in the achetypal strongly correlated electron system of YbB{sub 12}.

Sluchanko, N. E., E-mail: nes@lt.gpi.ru; Azarevich, A. N.; Bogach, A. V.; Glushkov, V. V.; Demishev, S. V.; Anisimov, M. A. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Levchenko, A. V.; Filipov, V. B.; Shitsevalova, N. Yu. [National Academy of Sciences of Ukraine, Frantsevich Institute for Problems of Materials Science (Ukraine)

2012-09-15

49

M"ossbauer Study of Eu14MnSb11 and Yb14MnSb11 Zintl Compounds.  

NASA Astrophysics Data System (ADS)

Antimony-121 M"ossbauer effect measurements have been performed mainly on Eu14MnSb11 and Yb14MnSb11 zintl compounds, through the temperature range from 2 K to room temperature. The isomer shifts observed (-4.5mm/sec to --10.3 mm/sec and -7.7 mm/sec to --11.2 mm/sec, respectively) from the present study for both Eu14MnSb11 and Yb14MnSb11 zintl compounds are close to the values (-8.54mm/sec to --8.73mm/sec) obtained for InSb, the standard compound for antimony-121 M"ossbauer effect measurements. Isomer shift distribution fits by using a Voigt-based Gaussian distribution profile show distinct peaks at the corresponding average isomer shift values obtained from Lorentzian four-site fits for Eu14MnSb11. The study of the temperature dependence of line broadening as well as hyperfine magnetic field confirms the existence of long-range magnetic ordering of antimony-121 in Eu14MnSb11 below 12 K which resulted in the transition temperature, TC, of 12 K, whereas TC found in Yb14MnSb11 is 45 K. The linear fit of the natural logarithm of area versus temperature using the Debye model for the high-temperature limit gives the values of 185 K and 196 K for the Debye temperature for Eu14MnSb11 and Yb14MnSb11 zintl compounds, respectively.

Kafle, Durga; Brown, Dennis

2006-05-01

50

White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals  

NASA Astrophysics Data System (ADS)

Ho3+/Tm3+/Yb3+ tri-doped glass ceramics with white light emitting have been developed and demonstrated. Pumped by 980 nm laser diode (LD), intensive red, green and blue up-conversions (UC) were obtained. The green emission is assigned to Ho3+ ion and the blue emission is assigned to Tm3+ ion, whereas the red emission is the combination contribution of the Ho3+ and Tm3+ ions. The RGB intensities could be adjusted by tuning the rare-earth ion concentration and pump power intensity. Thus, multicolor of the luminescence, including perfect white light with CIE-X=0.329 and CIE-Y=0.342 in the 1931 CIE chromaticity diagram can be obtained in 0.15 Ho3+/0.2Tm3+/3Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals pumped by a single infrared laser diode source of 980 nm at 500 mW. The up-conversion luminescence mechanism of Yb3+ sensitize Ho3+ and Tm3+ ions and the energy transfer from Ho3+ to Tm3+ in oxy-fluoride silicate glass ceramics were analyzed.

Li, Chenxia; Xu, Shiqing; Ye, Rengguang; Deng, Degang; Hua, Youjie; Zhao, Shilong; Zhuang, Songlin

2011-04-01

51

The action mechanism of TiO2:NaYF4:Yb3+,Tm3+ cathode buffer layer in highly efficient inverted organic solar cells  

NASA Astrophysics Data System (ADS)

We report the fabrication and characteristics of organic solar cells with 6.86% power conversion efficiency (PCE) by doping NaYF4:Yb3+,Tm3+ into TiO2 cathode buffer layer. The dependence of devices performance on doping concentration of NaYF4:Yb3+,Tm3+ is investigated. Results indicate that short-circuit current density (Jsc) has an apparent improvement, leading to an enhancement of 22.7% in PCE for the optimized doping concentration of 0.05 mmol ml-1 compared to the control devices. NaYF4:Yb3+,Tm3+ nanoparticles (NPs) can play threefold roles, one is that the incident light in visible region can be scattered by NaYF4 NPs, the second is that solar irradiation in infrared region can be better utilized by Up-conversion effect of Yb3+ and Tm3+ ions, the third is that electron transport property in TiO2 thin film can be greatly improved.

Liu, Chunyu; Chen, Huan; Zhao, Dan; Shen, Liang; He, Yeyuan; Guo, Wenbin; Chen, Weiyou

2014-08-01

52

Investigation on luminescence properties of Er3+-Yb3+-Tm3+ co-doped Gd2O3 hollow microspheres  

NASA Astrophysics Data System (ADS)

The Gd2O3 hollow microspheres have been successfully fabricated via carbonaceous polysaccharide microspheres as templates and urea as a precipitating agent, which involved the deposition of an inorganic coating on the surface of carbon microsphere, followed by heat treated 800°C for 4h. The obtained high uniform Gd2O3 microspheres with a spherical shape and hollow structure are uniform in size and distribution. The possible mechanism of evolution from glucose to carbonaceous polysaccharide microspheres and the chemical reaction of each step to form the final hollow spheres are proposed. The rare earth ion Ln3+ doped Gd2O3 (Ln = Er, Yb and Tm) hollow microspheres show bright up-conversion luminescence with different colors coming from different activator ions under ultraviolet or 980 nm light excitation, which may open new possibilities to synthesize other hollow spherical materials and extend their applications.

Xu, Fang; Han, Wan-lei; Liu, Xiao-bo; Song, Ying-lin

2011-06-01

53

Near-infrared photocatalysts of BiVO?/CaF?:Er³?, Tm³?, Yb³? with enhanced upconversion properties.  

PubMed

Upconversion photocatalysts have the potential to absorb the near-infrared (NIR) light in solar energy and improve the photocatalytic performance. A hierarchical upconversion photocatalyst of BiVO? (BVO)/CaF?:Er(3+), Tm(3+), Yb(3+) (CF) combined with the narrow-band semiconductor of BVO and the luminescence agent of CF to enhance upconversion properties was synthesized via the hydrothermal method. The CF particles were deposited homogeneously on the surface of the BVO/CF composite with regular dendritic structure, which led to efficient upconversion emissions. The upconversion emission intensity of the BVO/CF composite was 8 times higher than that of pure CF, through tailoring the crystal symmetry of lanthanide ions by Bi(3+) ions. The upconverted ultraviolet (361 and 379 nm), violet (408 nm), and blue (485 nm) light was able to excite BVO for photocatalysis in BVO/CF under NIR irradiation, which improved the degradation rate of methyl orange (MO). PMID:24302062

Huang, Shouqiang; Zhu, Nanwen; Lou, Ziyang; Gu, Lin; Miao, Chen; Yuan, Haiping; Shan, Aidang

2014-01-01

54

Colour emission tunability in Ho3+-Tm3+-Yb3+ co-doped Y2O3 upconverted phosphor  

NASA Astrophysics Data System (ADS)

The frequency upconversion (UC) emission throughout the visible region from the Y2O3:Ho3+-Tm3+-Yb3+ co-doped phosphors synthesized by using low temperature combustion process upon excitation with a diode laser operating at 980 nm have been presented. The colour emission tunability in co-doped phosphor has been observed on increasing the pump power and seen by the naked eyes. The tunability in colour emission has also been visualized by CIE chromaticity diagram. The variation in UC emission intensity of the 1G4 ? 3H6 (Tm3+) and 5F3 ? 5I8 (Ho3+) transitions lying in the blue region has been monitored with increase in the pump power and marked that their ratio can be used to determine the temperature. The developed phosphor has been used to record fingerprints. The observed most intense visible colour emission from the developed material may be used for photodynamic therapy and as an alternative of traditional fluorescent biolabels.

Pandey, Anurag; Rai, Vineet Kumar

2012-12-01

55

Multifunctional SiO2@Gd2O3:Yb/Tm Hollow Capsules: Controllable Synthesis and Drug Release Properties.  

PubMed

A series of hollow and luminescent capsules have been fabricated by covering luminescent Gd2O3:Yb/Tm nanoparticles on the surface of uniform hollow mesoporous silica capsules (HMSCs), which were obtained from an etching process using Fe3O4 as hard templates. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), up-conversion (UC) fluorescence spectra, and N2 adsorption-desorption were used to characterize these samples. It is found that the as-prepared products have mesoporous pores, large specific surface, and high dispersity. In particular, the size, shape, surface area, and interior space of the composites can be finely tuned by adjusting the size and morphology of the magnetic cores. Under 980 nm near-infrared (NIR) laser irradiation, the composites show characteristic blue UC emissions of Tm(3+) even after carrying doxorubicin hydrochloride (DOX). The drug-release test reveals that the capsules showed an apparent sustained release character and released in a pH-sensitive manner. Interestingly, the UC luminescence intensity of the drug-carrying system increases with the released DOX, realizing the possibility to track or monitor the released drug by the change of UC fluorescence simultaneously, which should be highly promising in anticancer drug delivery and targeted cancer therapy. PMID:25285784

Yang, Guixin; Lv, Ruichan; Gai, Shili; Dai, Yunlu; He, Fei; Yang, Piaoping

2014-10-20

56

White light generation in Tm3+/Ho3+/Yb3+ doped PbO-GeO2 glasses excited at 980 nm  

NASA Astrophysics Data System (ADS)

We report white light generation (WLG) in Tm3+/Ho3+/Yb3+ doped PbO-GeO2 glass under continuous-wave excitation at 980 nm. Intense blue (?477 nm), green (?545 nm), and red (? 658 nm) emissions were simultaneously observed at room temperature. The blue light is mainly due to the Tm3+ transition 1G4 ? 3H6. The green emission is due to the Ho3+ transitions (5S2, 5F4) ? 5I8 and the red luminescence is due to the Ho3+ transition 5F5 ? 5I8 and transition 1G4 ? 3F4 associated to the Tm3+ ions. Energy transfer processes from Yb3+ to Ho3+ and Yb3+ to Tm3+ ions were responsible for the WLG. Adjusting the relative concentration of the rare-earth (RE) ions, we could obtain emission in the white region of the CIE chromaticity diagram. The present results indicate that PbO-GeO2 glass has large potential to be used for white displays.

Camilo, M. E.; Silva, E. de O.; de Assumpção, Thiago A. A.; Kassab, Luciana R. P.; de Araújo, Cid B.

2013-10-01

57

Spectroscopic properties and mechanism of Tm3+/Er3+/Yb3+co-doped oxyfluorogermanate glass ceramics containing BaF2 nanocrystals  

NASA Astrophysics Data System (ADS)

Transparent Tm3+/Er3+/Yb3+ co-doped oxyfluorogermanate glass ceramics containing BaF2 nanocrystals are prepared. Under excitation of a 980-nm laser diode (LD), compared with the glass before heat treatment, the Tm3+/Er3+/Yb3+co-doped oxyfluorogermanate glass ceramics can emit intense blue, green and red up-conversion luminescence and Stark-split peaks; X-ray diffraction (XRD) and transmission electron microscope (TEM) results show that BaF2 nanocrystals with an average diameter of 20 nm are precipitated from the glass matrix. Stark splitting of the up-conversion luminescence peaks in the glass ceramics indicates that Tm3+, Er3+ and (or) Yb3+ ions are incorporated into the BaF2 nanocrystals. The up-conversion luminescence intensities of Tm3+, Er3+ and the splitting degree of luminescence peaks in the glass ceramics increase significantly with the increase of heat treat temperature and heat treat time extension. In addition, the possible energy transfer process between rare earth ions and the up-conversion luminescence mechanism are also proposed.

Hu, Yue-Bo; Qiu, Jian-Bei; Zhou, Da-Cheng; Song, Zhi-Guo; Yang, Zheng-Wen; Wang, Rong-Fei; Jiao, Qing; Zhou, Da-Li

2014-02-01

58

Highly efficient Yb3+/Tm3+ co-doped NaYF4 nanotubes: Synthesis and intense ultraviolet to infrared up-conversion luminescence  

NASA Astrophysics Data System (ADS)

Nanocrystals of up-conversion (UC) phosphor Yb3+/Tm3+ co-doped NaYF4 are prepared by a facile hydrothermal method using oleic acid as a stabilizing agent. The as-prepared nanocrystals are of hexagonal phase, and have tube-like morphology and strong ultraviolet (UV) and blue UC fluorescence intensity, which have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and luminescence spectroscopy. The effect of Yb3+ concentration on the UC emission properties is also analyzed. Our results reveal that the intensity of emission peaks can be controlled by varying the Yb3+ concentration and these NaYF4 nanotubes are highly efficient host material. The as-prepared NaYF4 nanotubes show potential applications in UV compact solid state lasers and multi-channel fluorescent label.

Zhang, Y. Y.; Wang, Y.; Deng, J. Q.; Wang, J.; Ni, S. C.

2014-02-01

59

White upconversion luminescence in Tm3+/Ho3+/Yb3+ triply doped K+-Na+ ion-exchanged aluminum germanate glass channel waveguide  

NASA Astrophysics Data System (ADS)

Rare-earth ions doped K+-Na+ ion-exchanged aluminum germanate (NMAG) glass channel waveguides have been designed and fabricated. Under 980 nm laser pumping, an intense upconversion white light transmission trace was observed in Tm3+/Ho3+/Yb3+ triply doped NMAG glass channel waveguide and a high-brightness light spot was achieved from the output end of the fiber connected to the waveguide channel. The fluorescent colors were diverse and located within or near the white region in CIE chromaticity diagram under various pumping powers. These admirable results indicate that Tm3+/Ho3+/Yb3+ triply doped NMAG channel waveguide is a promising light source for medical and high-precision processing illumination.

Liu, Xiao; Chen, Baojie; Pun, Edwin Yue Bun; Lin, Hai

2013-01-01

60

Activation of SO2 with [(?(5) -C5 Me5 )2 Ln(THF)2 ] (Ln=Eu, Yb) leading to dithionite and sulfinate complexes.  

PubMed

The reaction of decamethylytterbocene [(?(5) -C5 Me5 )2 Yb(THF)2 ] with SO2 at low temperature gave two new compounds, namely, the Yb(III) dithionite/sulfinate complex [{(?(5) -C5 Me5 )2 Yb(?3 ,1?(2) O(1,3) ,2?(3) O(2,2',4) -S2 O4 )}2 {(?(5) -C5 Me5 )Yb(?,1?O,2?O'-C5 Me5 SO2 )}2 ] (1) and the Yb(III) dithionite complex [{(?(5) -C5 Me5 )2 Yb}2 (?,1?(2) O(1,3) ,2?(2) O(2,4) -S2 O4 )] (2). After extraction of 1, the mixture was heated to give the dinuclear tetrasulfinate complex [{(?(5) -C5 Me5 )Yb}2 (?,?O,?O'-C5 Me5 SO2 )4 ] (3?a). In contrast, from the reaction of [(?(5) -C5 Me5 )2 Eu(THF)2 ] with SO2 only the tetrasulfinate complex [{(?(5) -C5 Me5 )Eu}2 (?,?O,?O'-C5 Me5 SO2 )4 ] (3?b) was isolated. Two major reaction pathways were observed: 1)?reductive coupling of two SO2 molecules to form the dithionite anion S2 O4 (2-) ; and 2)?nucleophilic attack of one metallocene C5 Me5 ligand on the sulfur atom of SO2 . The compounds presented are the first dithionite and sulfinate complexes of the f-elements. PMID:25196130

Klementyeva, Svetlana V; Gamer, Michael T; Schmidt, Anna-Corina; Meyer, Karsten; Konchenko, Sergey N; Roesky, Peter W

2014-10-13

61

Yellow-orange upconversion emission in Eu3+-Yb3+ codoped BaTiO3 phosphor  

NASA Astrophysics Data System (ADS)

The Eu3+-Yb3+ codoped BaTiO3 phosphor is prepared via co-precipitation method and its upconversion emission is studied by 980 nm diode laser excitation. The X-ray diffraction pattern of the prepared sample showed the tetragonal BaTiO3 phase. The co-doped phosphor showed sharp upconversion emission bands peaking at ?592, ?614, ? 654, ?704 and ?796 nm due to the 5D0 ? 7F1, 5D0 ? 7F2, 5D0 ? 7F3, 5D0 ? 7F4 and 5D0 ? 7F6 transitions, respectively of Eu3+ ions. The sharp band at 489 nm is assigned to the 2F5/2 ? 2F7/2 transition of Yb3+ ion while the broad band around 505 nm is assigned to the defect states present in the sample. Based on the available experimental data, the process involved in the UC emissions has been explored and elaborated.

Kumari, Astha; Rai, Vineet Kumar; Kumar, Kaushal

2014-06-01

62

Multifunctional Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles synthesized by reverse micelle method.  

PubMed

Synthesis of Eu(3+)- and Er(3+)/Yb(3+)-doped GdVO4 nanoparticles in reverse micelles and their multifunctional luminescence properties are presented. Using cyclohexane, Triton X-100, and n-pentanol as the oil, surfactant, and co-surfactant, respectively, crystalline nanoparticles with ~4?nm diameter are prepared at low temperatures. The particle size assessed using transmission electron microscopy is similar to the crystallite size obtained from X-ray diffraction measurements, suggesting that each particle comprises a single crystallite. Eu(3+)-doped GdVO4 nanoparticles emit red light through downconversion upon UV excitation. Er(3+)/Yb(3+)-doped GdVO4 nanoparticles exhibit several functions; apart from the downconversion of UV radiation into visible green light, they act as upconvertors, transforming near-infrared excitation (980?nm) into visible green light. The ratio of green emissions from (2)H11/2 ? (2)I15/2 and (4)S3/2 ? (4)I15/2 transitions is temperature dependent and can be used for nanoscale temperature sensing with near-infrared excitation. The relative sensor sensitivity is 1.11%K(-1), which is among the highest sensitivities recorded for upconversion-luminescence-based thermometers. PMID:24572638

Gavrilovi?, Tamara V; Jovanovi?, Dragana J; Lojpur, Vesna; Drami?anin, Miroslav D

2014-01-01

63

Multifunctional Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles synthesized by reverse micelle method  

NASA Astrophysics Data System (ADS)

Synthesis of Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles in reverse micelles and their multifunctional luminescence properties are presented. Using cyclohexane, Triton X-100, and n-pentanol as the oil, surfactant, and co-surfactant, respectively, crystalline nanoparticles with ~4 nm diameter are prepared at low temperatures. The particle size assessed using transmission electron microscopy is similar to the crystallite size obtained from X-ray diffraction measurements, suggesting that each particle comprises a single crystallite. Eu3+-doped GdVO4 nanoparticles emit red light through downconversion upon UV excitation. Er3+/Yb3+-doped GdVO4 nanoparticles exhibit several functions; apart from the downconversion of UV radiation into visible green light, they act as upconvertors, transforming near-infrared excitation (980 nm) into visible green light. The ratio of green emissions from 2H11/2 --> 2I15/2 and 4S3/2 --> 4I15/2 transitions is temperature dependent and can be used for nanoscale temperature sensing with near-infrared excitation. The relative sensor sensitivity is 1.11%K-1, which is among the highest sensitivities recorded for upconversion-luminescence-based thermometers.

Gavrilovi?, Tamara V.; Jovanovi?, Dragana J.; Lojpur, Vesna; Drami?anin, Miroslav D.

2014-02-01

64

Multifunctional Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles synthesized by reverse micelle method  

PubMed Central

Synthesis of Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles in reverse micelles and their multifunctional luminescence properties are presented. Using cyclohexane, Triton X-100, and n-pentanol as the oil, surfactant, and co-surfactant, respectively, crystalline nanoparticles with ~4?nm diameter are prepared at low temperatures. The particle size assessed using transmission electron microscopy is similar to the crystallite size obtained from X-ray diffraction measurements, suggesting that each particle comprises a single crystallite. Eu3+-doped GdVO4 nanoparticles emit red light through downconversion upon UV excitation. Er3+/Yb3+-doped GdVO4 nanoparticles exhibit several functions; apart from the downconversion of UV radiation into visible green light, they act as upconvertors, transforming near-infrared excitation (980?nm) into visible green light. The ratio of green emissions from 2H11/2 ? 2I15/2 and 4S3/2 ? 4I15/2 transitions is temperature dependent and can be used for nanoscale temperature sensing with near-infrared excitation. The relative sensor sensitivity is 1.11%K?1, which is among the highest sensitivities recorded for upconversion-luminescence-based thermometers. PMID:24572638

Gavrilovic, Tamara V.; Jovanovic, Dragana J.; Lojpur, Vesna; Dramicanin, Miroslav D.

2014-01-01

65

Characteristics of rare earth (RE = Eu, Tb, Tm)-doped Y2O3 phosphors for thermometry.  

PubMed

The temperature-dependent photoluminescences of Y(2)O(3) : Eu (6% Eu), Y(2)O(3) : Tb (4% Tb) and Y(2)O(3) : Tm (1% Tm) were investigated for high-temperature phosphor thermometry. Two different phases, the monoclinic phase and cubic phase, were considered because the fluorescence spectra vary with the phase. To employ the intensity ratio method, we investigated their photoluminescence spectra under the excitation light of an Hg-Xe lamp as the temperature was elevated from room temperature to more than 1200 K. As a result, it was confirmed that the luminescence intensity of all of the phosphors varied with elevating temperature, i.e. thermal quenching, with the variations depending on the type of rare earth impurity and their phases. The results indicate that Y(2)O(3) : Eu phosphors are applicable to the intensity ratio method because they show appropriate variations in the intensity ratio of two emission lines, and they also have strong and sharp peak intensities without excessive optical noise or black body radiation over a wide range of temperatures. The intensity ratios for Y(2)O(3) : Tb provide such small variations with temperature that the temperature resolution is low, despite the strong emission intensities. As for Y(2) O(3) :Tm, the intensity ratios also have a low temperature resolution and their emission intensities are weak. Therefore, Y(2)O(3) : Tb and Y(2)O(3) : Tm are not appropriate for the intensity ratio method for phosphor thermometry. PMID:20737651

Ishiwada, Naohiro; Ueda, Toshihisa; Yokomori, Takeshi

2011-01-01

66

Preparation of Ca2Si5N8:Eu2+,Tm3+ phosphor by calcium hydride and its afterglow properties  

NASA Astrophysics Data System (ADS)

Reddish-orange emitting long-lasting phosphorescence phosphor Ca2Si5N8:Eu2+,Tm3+ has been prepared by solid-state reaction method using cheaper CaH2 as calcium source. Upon UV light excitation, Ca2Si5N8:Eu2+,Tm3+ phosphor gave a broad band emission peaking at ca. 600 nm. Furthermore, after irradiation by the UV or visible light (in the range of 250-400 nm) for 3 min, the same colored intense afterglow based on the 4f65d1-->4f7 transition of Eu2+ ion was observed on the phosphor codoped with 0.5 at% of Eu2+ and Tm3+ ions, and its afterglow can be seen with the naked eye in the dark clearly for more than 1 h after removal of the excitation source. The afterglow decay curve contained fast decay and slow decay components. The substitution of Mg2+ to Ca2+ ions or addition of excessive Ca2+ ions into the phosphor matrix to modify the defect environment were effective to improve the afterglow properties.

Lei, Bingfu; Machida, Ken-ichi; Horikawa, Takashi; Hanzawa, Hiromasa

2009-07-01

67

Influence of silver nanoparticles on the infrared-to-visible frequency upconversion in Tm3+/Er3+/Yb3+ doped GeO2-PbO glass  

NASA Astrophysics Data System (ADS)

We investigated the influence of silver nanoparticles (NPs) on the infrared-to-visible frequency upconversion (UC) in GeO2-PbO glass triply doped with thulium (Tm3+), erbium (Er3+), and ytterbium (Yb3+) ions. The NPs were nucleated inside the samples by heat-treatment of the germanate glass that included small amount of AgNO3 in the starting composition. When excited at 980 nm, in resonance with the Yb3+ transition 2F7/2 ? 2F5/2, the samples emit blue light at ?477 nm due to the Tm3+ ions, green light at ?530 nm and ?550 nm due to the Er3+ ions, and red light at ?652 nm due to Tm3+ and at ?660 nm due to the Er3+ ions. Due to the silver NPs, the photoluminescence intensity grows by ?60% in comparison with a sample having the same composition but without silver NPs. This is the first time that UC enhancement due to metallic NPs is investigated for a triply rare-earth (RE) doped glass. The results indicate the possibility of development of more efficient three-dimensional RE based color displays by nucleation of metallic particles in the glass host.

Camilo, Mauricio E.; Assumpção, Thiago A. A.; da Silva, Davinson M.; da Silva, Diego S.; Kassab, Luciana R. P.; de Araújo, Cid B.

2013-04-01

68

Compositional dependence of g-factor and damping constant of (Gd100-xREx)FeCo alloy films (RE = Yb, Tm, Er)  

NASA Astrophysics Data System (ADS)

Time domain magnetization dynamics of (Gd100-xREx)FeCo (RE = Yb, Tm, Er) alloy films with various compositions were measured by pump-probe method using a high energy ultra short pulse fiber laser, and their g-factors and damping constants were estimated. The g-factor of GdFeCo became large near the angular moment compensation point CA, which is qualitatively consistent with the simple mean field model. On the other hand, the damping constants took a maximum near magnetization compensation point, which is not described by the mean field model. Substitution of Tm or Er for Gd results in the significant increase of damping constant; (Gd90Tm10)FeCo and (Gd90Er10)FeCo exhibit roughly 3-6 times large damping constant compared to GdFeCo, while (Gd90Yb10)FeCo has almost the same damping constant as GdFeCo. This means that the damping constant is significantly modified by the orbital moment of RE atoms.

Komiya, R.; Kato, T.; Nishizawa, N.; Tsunashima, S.; Iwata, S.

2010-01-01

69

Additive colouring of CaF2:Yb crystals: determination of Yb2+ concentration in CaF2:Yb crystals and ceramics  

NASA Astrophysics Data System (ADS)

When growing CaF2 crystal doped with rare-earth ions, most of these ions are present in a trivalent state. However, due to contact with graphite crucible, a small proportion of a number of ions (Eu, Sm, Yb and Tm) are reduced to a bivalent state. A similar situation takes place during fabrication of CaF2 ceramics doped with rare-earth metals. This fact is of particular importance for laser CaF2:Yb crystals (ceramics), a promising material for short-pulse, high-power, high-energy diode-pumped solid state lasers since the presence of bivalent Yb ions can be a source of thermal losses. To date, there has been no technique to determine Yb2+ concentration in as-grown crystals. The proposed technique is based on a total reduction of Yb3+ ions via the heating of as-grown CaF2 crystals with known concentration of Yb in the reducing atmosphere of metal vapour and determining the cross section of absorption bands of Yb2+ ions. The knowledge of these parameters allows estimation of the Yb2+ content in CaF2:Yb crystals or ceramics by analysing their absorption spectra. Examples of using this technique are given. The technology of CdF2 crystals reduction (an "additive colouring") and features of colouring of crystals doped with rare-earth ions are considered.

Shcheulin, A. S.; Angervaks, A. E.; Semenova, T. S.; Koryakina, L. F.; Petrova, M. A.; Fedorov, P. P.; Reiterov, V. M.; Garibin, E. A.; Ryskin, A. I.

2013-06-01

70

Jahn-Teller distortion and magnetic transitions in perovskite RMnO3 ( R=Ho , Er, Tm, Yb, and Lu)  

NASA Astrophysics Data System (ADS)

The perovskite RMnO3 ( R=Ho , Er, Tm, Yb, and Lu) were prepared under high pressure and studied with heat capacity and synchrotron x-ray powder diffraction measurements. The temperature interval between the antiferromagnetic transition and the first-order transition to the presumably E -type structure narrows with the decreasing ionic radius of R , and almost closes for R=Lu . Combined with the data for the larger rare earth R , the results show intricate relationship between the complex magnetic phase diagram and significant increase of Jahn-Teller distortion found for the smallest members of RMnO3 .

Tachibana, Makoto; Shimoyama, Tomotaka; Kawaji, Hitoshi; Atake, Tooru; Takayama-Muromachi, Eiji

2007-04-01

71

Facile fabrication and upconversion luminescence enhancement of LaF3:Yb3+/Ln3+@SiO2 (Ln = Er, Tm) nanostructures decorated with Ag nanoparticles.  

PubMed

A novel hybrid nanostructure, that is a Ag nanoparticle decorated LaF(3):Yb(3+)/Ln(3+)@SiO(2) nanosphere (Ln=Er, Tm), was constructed by a facile strategy, and characterized by XRD, TEM, FTIR, XPS and UV-vis-NIR absorption. Obvious spectral broadening and red-shift on the surface plasmon resonance were obtained by adjusting the size and configuration of Ag nanoparticles. Effective upconversion luminescence enhancements for Er(3+) and Tm(3+) containing samples were obtained. It is suggested that the luminescence enhancement results from both the excitation and emission processes, and the configuration of the studied hybrid nanostructure is an efficient system to enhance the luminescence emission of rare earth doped nanomaterials. It is believed that the enhancement from the hybrid nanostructure will find great potential in the development of photovoltaic solar cells. PMID:24398901

He, Enjie; Zheng, Hairong; Dong, Jun; Gao, Wei; Han, Qingyan; Li, Junna; Hui, Le; Lu, Ying; Tian, Huani

2014-01-31

72

Facile fabrication and upconversion luminescence enhancement of LaF3:Yb3+/Ln3+@SiO2 (Ln=Er, Tm) nanostructures decorated with Ag nanoparticles  

NASA Astrophysics Data System (ADS)

A novel hybrid nanostructure, that is a Ag nanoparticle decorated LaF3:Yb3+/Ln3+@SiO2 nanosphere (Ln=Er, Tm), was constructed by a facile strategy, and characterized by XRD, TEM, FTIR, XPS and UV-vis-NIR absorption. Obvious spectral broadening and red-shift on the surface plasmon resonance were obtained by adjusting the size and configuration of Ag nanoparticles. Effective upconversion luminescence enhancements for Er3+ and Tm3+ containing samples were obtained. It is suggested that the luminescence enhancement results from both the excitation and emission processes, and the configuration of the studied hybrid nanostructure is an efficient system to enhance the luminescence emission of rare earth doped nanomaterials. It is believed that the enhancement from the hybrid nanostructure will find great potential in the development of photovoltaic solar cells.

He, Enjie; Zheng, Hairong; Dong, Jun; Gao, Wei; Han, Qingyan; Li, Junna; Hui, Le; Lu, Ying; Tian, Huani

2014-01-01

73

Pressure study of the magnetic and electrical properties of the Eu-Yb alloy system  

Microsoft Academic Search

Measurements of the ac magnetic susceptibility, magnetization, and electrical resistivity at hydrostatic pressures up to 15 kbar and of the thermal expansion were made for the EuxYb1-x alloy system (x<=0.4) in temperatures from 1.6 to 400 K. The paramagnetic-ferromagnetic transition temperature Tc versus pressure p curve for x=0.025 has a maximum near p=1 kbar. For x=0.25, Tc decreases and the

H. Kadomatsu; T. Tsutaoka; H. Fujiwara

1985-01-01

74

Synthesis, crystal structures, magnetic and electric transport properties of Eu{sub 11}InSb{sub 9} and Yb{sub 11}InSb{sub 9}  

SciTech Connect

Two new rare-earth metal containing Zintl phases, Eu{sub 11}InSb{sub 9} and Yb{sub 11}InSb{sub 9} have been synthesized by reactions of the corresponding elements in molten In metal to serve as a self-flux. Their crystal structures have been determined by single crystal X-ray diffraction-both compounds are isostructural and crystallize in the orthorhombic space group Iba2 (No. 45), Z=4 with unit cell parameters a=12.224(2) A, b=12.874(2) A, c=17.315(3) A for Eu{sub 11}InSb{sub 9}, and a=11.7886(11) A, b=12.4151(12) A, c=16.6743(15) A for Yb{sub 11}InSb{sub 9}, respectively (Ca{sub 11}InSb{sub 9}-type, Pearson's code oI84). Both structures can be rationalized using the classic Zintl rules, and are best described in terms of discrete In-centered tetrahedra of Sb, [InSb{sub 4}]{sup 9-}, isolated Sb dimers, [Sb{sub 2}]{sup 4-}, and isolated Sb anions, Sb{sup 3-}. These anionic species are separated by Eu{sup 2+} and Yb{sup 2+} cations, which occupy the empty space between them and counterbalance the formal charges. Temperature-dependent magnetic susceptibility and resistivity measurements corroborate such analysis and indicate divalent Eu and Yb, as well as poorly metallic behavior for both Eu{sub 11}InSb{sub 9} and Yb{sub 11}InSb{sub 9}. The close relationships between these structures and those of the monoclinic {alpha}-Ca{sub 21}Mn{sub 4}Sb{sub 18} and Ca{sub 21}Mn{sub 4}Bi{sub 18} are also discussed. - Graphical abstract: Reported are the synthesis, the structure and the magnetic and electronic properties of two new rare-earth Zintl phases, Eu{sub 11}InSb{sub 9} and Yb{sub 11}InSb{sub 9}. The close relationships between these structures and those of the monoclinic {alpha}-Ca{sub 21}Mn{sub 4}Sb{sub 18} and Ca{sub 21}Mn{sub 4}Bi{sub 18} are also discussed.

Xia Shengqing [Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 (United States); Hullmann, Jonathan [Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 (United States); Bobev, Svilen [Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 (United States)], E-mail: bobev@udel.edu; Ozbay, Arif [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Nowak, Edmund R. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Fritsch, Veronika [Physikalisches Institut, Universitaet Karlsruhe (Thailand), 76128 Karlsruhe (Germany)

2007-07-15

75

High pressure effect on structural and mechanical properties of some LnO (Ln=Sm, Eu, Yb) compounds  

NASA Astrophysics Data System (ADS)

The structural and mechanical properties of LnO (Ln=Sm, Eu, Yb) compounds have been investigated using a modified interionic potential theory, which includes the effect of Coulomb screening. We predicted a structural phase transition from NaCl (B 1)- to CsCl (B 2)-type structure and elastic properties in LnO compounds at very high pressure. The anomalous properties of these compounds have been correlated in terms of the hybridisation of f-electrons of the rare earth ion with conduction band and strong mixing of f-states of lanthanides with the p-orbital of neighbouring chalcogen ion. For EuO, the calculated transition pressure, bulk modulus and lattice parameter are close to the experimental data. The nature of bonds between the ions is predicted by simulating the ion-ion (Ln-Ln and Ln-O) distances at high pressure. The second order elastic constants along with shear modulus and Young's modulus, elastic anisotropy and Poisson's ratio are also presented for these oxides.

Srivastava, Vipul; Bhajanker, Sanjay; Sanyal, Sankar P.

2011-05-01

76

Hydrothermal synthesis of NaLuF4:153Sm,Yb,Tm nanoparticles and their application in dual-modality upconversion luminescence and SPECT bioimaging.  

PubMed

Upconversion luminescence (UCL) properties and radioactivity have been integrated into NaLuF(4):(153)Sm,Yb,Tm nanoparticles by a facile one-step hydrothermal method, making these nanoparticles potential candidates for UCL and single-photon emission computed tomography (SPECT) dual-modal bioimaging in vivo. The introduction of small amount of radioactive (153)Sm(3+) can hardly vary the upconversion luminescence properties of the nanoparticles. The as-designed nanoparticles showed very low cytotoxicity, no obvious tissue damage in 7 days, and excellent in vitro and in vivo performances in dual-modal bioimaging. By means of a combination of UCL and SPECT imaging in vivo, the distribution of the nanoparticles in living animals has been studied, and the results indicated that these particles were mainly accumulated in the liver and spleen. Therefore, the concept of (153)Sm(3+)/Yb(3+)/Tm(3+) co-doped NaLuF(4) nanoparticles for UCL and SPECT dual-modality imaging in vivo of whole-body animals may serve as a platform for next-generation probes for ultra-sensitive molecular imaging from the cellular scale to whole-body evaluation. It also introduces an easy methodology to quantify in vivo biodistribution of nanomaterials which still needs further understanding as a community. PMID:23117216

Yang, Yang; Sun, Yun; Cao, Tianye; Peng, Juanjuan; Liu, Ying; Wu, Yongquan; Feng, Wei; Zhang, Yingjian; Li, Fuyou

2013-01-01

77

T.M. Biewer, April 4th, 2003 US/EU Transport Task Force Meeting, Madison, WI Edge Impurity Ion Velocity and  

E-print Network

, April 4th, 2003 US/EU Transport Task Force Meeting, Madison, WI Abstract A new spectroscopic diagnosticT.M. Biewer, April 4th, 2003 US/EU Transport Task Force Meeting, Madison, WI Edge Impurity Ion Plasma Physics Laboratory April 4th, 2003 Transport Task Force Meeting Madison, Wisconsin #12;T.M. Biewer

Biewer, Theodore

78

Red, Green, and Blue Light Through Cooperative Up-Conversion in Sol-Gel Thin Films Made With Yb0.80La0.15Tb0.05F3 and Yb0.80La0.15Eu0.05F3 Nanoparticles  

NASA Astrophysics Data System (ADS)

Silica and zirconium dioxide sol-gel thin films made with Yb0.80La0.15Tb0.05F3 or Yb0.80La0.15Eu0.05F3 nanoparticles are reported. Bright blue (413 and 435 nm), green (545 nm), and red (585 and 625 nm) emissions are produced from Tb3+ ions through cooperative up-conversion of 980 nm light. Similarly, red (591 and 612 nm) emission is generated from Eu3+ ions. These up-convertors may find use in white light sources. The cooperative up-conversion of Yb3+ - Tb3+ ions is more efficient than of Yb3+ - Eu3+ ions because the efficiency of energy transfer from excited Yb3+ ions to a Tb3+ ion (0.37) is more than two-times higher than of excited Yb3+ ions to a Eu3+ ion (0.15), as estimated from the lifetime of excited Yb3+ ion. The estimated quantum yields of both Tb3+ ion and Eu3+ ion emissions are on the order of 40%, and hence are not the cause of the difference in efficiency. This approach does not work for Sm3+, Pr3+, and Dy3+. Incorporation of the respective Ln3+ ions in nanoparticles is crucial, as controls, in which the various Ln3+ ions are incorporated directly into the sol-gel, that do not show cooperative up-conversion.

Sivakumar, Sri; van Veggel, Frank C. J. M.

2007-06-01

79

Hydrothermal derived LaOF:Ln3+ (Ln = Eu, Tb, Sm, Dy, Tm, and/or Ho) nanocrystals with multicolor-tunable emission properties.  

PubMed

A series of LaOF:Ln(3+) (Ln = Eu, Tb, Sm, Dy, Tm, and/or Ho) nanocrystals with good dispersion have been successfully prepared by the hydrothermal method followed a heat-treatment process. Under ultraviolet radiation and low-voltage electron beam excitation, the LaOF:Ln(3+) nanocrystals show the characteristic f-f emissions of Ln(3+) (Ln = Eu, Tb, Sm, Dy, Tm, or Ho) and give red, blue-green, orange, yellow, blue, and green emission, respectively. Moreover, there exists simultaneous luminescence of Tb(3+), Eu(3+), Sm(3+), Dy(3+), Tm(3+), or Ho(3+) individually when codoping them in the single-phase LaOF host (for example, LaOF:Tb(3+), Eu(3+)/Sm(3+); LaOF:Tm(3+), Dy(3+)/Ho(3+); LaOF:Tm(3+), Ho(3+), Eu(3+) systems), which is beneficial to tune the emission colors. Under low-voltage electron beam excitation, a variety of colors can be efficiently adjusted by varying the doping ions and the doping concentration, making these materials have potential applications in field-emission display devices. More importantly, the energy transfer from Tm(3+) to Ho(3+) in the LaOF:Tm(3+), Ho(3+) samples under UV excitation was first investigated and has been demonstrated to be a resonant type via a quadrupole-quadrupole mechanism. The critical distance (R(Tm-Ho)) is calculated to be 28.4 Å. In addition, the LaOF:Tb(3+) and LaOF:Tm(3+) phosphors exhibit green and blue luminescence with better chromaticity coordinates, color purity, and higher intensity compared with the commercial green phosphor ZnO:Zn and blue phosphor Y(2)SiO(5):Ce(3+) to some extent under low-voltage electron beam excitation. PMID:23020114

Shang, Mengmeng; Geng, Dongling; Kang, Xiaojiao; Yang, Dongmei; Zhang, Yang; Lin, Jun

2012-10-15

80

Controlled growth, intense upconversion emissions and concentration induced luminescence switching of bifunctional Tm3+ doped hexagonal NaYb0.55Gd0.45F4 nanorods  

NASA Astrophysics Data System (ADS)

Bifunctional hexagonal Tm3+ doped NaYb0.55Gd0.45F4 nanorods with tunable size are prepared via in situ cation-exchange reaction using hydrothermal method. The measured field dependence of magnetization of the NaYb0.55Gd0.45F4 nanorods shows typical paramagnetic characteristics that can be ascribed to the non-interacting localized nature of the magnetic moment of rare-earth ions. When excited by a 980 nm laser, these nanorods exhibit intense multi-color up-conversion (UC) emissions in infrared, red, blue and especially ultraviolet. In addition, luminescent switching between different UC emission wavelengths of 480 nm and 450 nm is observed by adjusting Tm3+ doping concentration. Based on power-dependent spectral analyses, it is found that with the increase of Tm3+ doping concentration, due to the suppressed saturation effect, the dominative UC process redistribute the populations at 1G4 and 1D2(Tm3+) states of Tm3+ ion resulting in the above luminescent switching. Our results indicate that bifunctional hexagonal NaYb1-xGdxF4 nanocrystals have potential applications in miniaturized solid-state light sources, optical processing sensors and fluorescent biolabels.

Qu, Xilong; Li, Yongchang; Yu, Suixi; Yang, Liwen

2013-11-01

81

Colour tuneability in sol-gel nano-glass-ceramics comprising Yb(3+)-Er(3+)-Tm3+ Co-doped NaYF4 nanocrystals.  

PubMed

White light can be obtained by up-conversion processes in a cheap and efficient way, being of great interest for lighting, displays, and photonic integrated devices. Here we report a generation of white light under 980 nm laser infrared excitation in Y(b3+)-Er(3+)-Tm3+ triply doped sol-gel derived nano-glass-ceramics containing NaYF4 nanocrystals where co-dopants ions are partitioned. Efficient simultaneous blue, green, and red up-conversion emissions give rise to a balanced white overall emission and corresponding up-conversion mechanisms have been analyzed. Changes in pump power intensity or heat treatment temperature widely vary the ratio of emission bands, resulting in a colour tuneability which has been analyzed and quantified in terms of CIE standard chromaticity diagram. PMID:20352788

Méndez-Ramos, J; Yanes, A C; Santana-Alonso, A; Del-Castillo, J; Rodríguez, V D

2010-02-01

82

Superconductivity of metal nitride chloride ?-MNCl (M = Zr, Hf) with rare-earth metal RE (RE = Eu, Yb) doped by intercalation  

NASA Astrophysics Data System (ADS)

Electrons were doped into the ?-form layered metal nitride chloride MNCl (M = Zr, Hf) by intercalation of rare-earth metals RE (RE = Eu, Yb) using liquid ammonia solutions. The intercalated compounds REx(NH3)yMNCl show superconductivity with transition temperatures Tc of ˜13 and 24.3 K for M = Zr and Hf, respectively, quite similar to the alkali metal intercalated analogs. The paramagnetic characteristics for Eu2+ and Yb3+ can coexist with superconductivity. The magnetic resistance measured on the uniaxially oriented Eu0.08(NH3)yHfNCl with the magnetic field parallel to the ab plane (? ab) and the c axis (? c) shows a strong anisotropic effect on the upper critical field Hc2; a large anisotropic parameter \\gamma ={H}_{{c}2}^{\\parallel a b}/{H}_{{c}2}^{\\parallel c}\\sim 4 suggests a pseudo-two-dimensional superconductivity. The Tc of Eu0.13(THF)yHfNCl is shifted toward a higher value of 25.8 K upon expansion of the interlayer spacing from 11.9 to 17.5 Å by co-intercalation of voluminous organic molecules such as tetrahydrofuran.

Zhang, Shuai; Tanaka, Masashi; Onimaru, Takahiro; Takabatake, Toshiro; Isikawa, Yosikazu; Yamanaka, Shoji

2013-04-01

83

Eu3+ and Yb3+ codoped Gd2O3 single phase nanophosphor: An enhanced monochromatic red emission through cooperative upconversion and downconversion  

NASA Astrophysics Data System (ADS)

Single phase cubic Gd2O3 nanophosphor codoped with Eu3+ and Yb3+ ions has been synthesized through solution combustion route. Structural properties have been investigated using x-ray diffraction (XRD) and transmission electron microscopy (TEM). The as-synthesized Gd2O3 phosphor shows amorphous nature which changes to crystalline single cubic phase on annealing. Optical properties have been investigated through absorption, photoluminescence, and lifetime measurements. Intense red emission (D50?F72) is observed both from cooperative upconversion (Yb3++Yb3+?Eu3+ on 976 nm excitation) as well as through downconversion process (on 355 nm excitation). The unusual and rarely reported emissions from the higher lying D5J (J=2, 3, and 4) to F7J (J=0, 1, 2, 3, and 4) levels are also observed with 976 nm excitation. Nearly twenty two times enhancement in the intensity of the hypersensitive transition (D50?F72) along with an increase in the decay time (770 ?s) is observed for the sample annealed at 1200 °C on 355 nm excitation. These observations have been explained satisfactorily.

Kaur, Gagandeep; Singh, S. K.; Rai, S. B.

2010-04-01

84

Enhanced performance of Ca2Si5N8:Eu2+, Tm3+ reddish-orange afterglow phosphor by co-doping with Dy3+  

NASA Astrophysics Data System (ADS)

Two types of reddish-orange afterglow emitting nitride phosphors Ca2Si5N8:Eu2+, Tm3+ (CSN:E, T) and Ca2Si5N8:Eu2+, Tm3+, Dy3+ (CSN:E, T, D) were synthesized via a solid-state reaction route and were comparatively investigated. Comparing with the di-doped CSN:E, T phosphor, the tri-doped CSN:E, T, D samples show higher afterglow intensity and longer duration time which can be attributed to the balanced defect micro-environment caused by the presence of Dy3+.

Zhang, Haoran; Dong, Hanwu; Lei, Bingfu; Wang, Peng; Li, Jinfang; Liu, Yingliang; Wang, Jing; Xiao, Yong; Zheng, Mingtao; Meng, Jianxin

2014-09-01

85

Crystal structures and reference powder patterns of BaRâZnOâ (R = La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, and Tm)  

Microsoft Academic Search

Reference x-ray powder patterns and the crystal structures of the lanthanide compounds, BaRâZnOâ, in which R = La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, or Tm were determined by the x-ray Rietveld refinement technique. A structural trend was confirmed for this series of compounds. The compounds with smaller ionic radii (R = Sm, Eu, Gd, Dy, Ho, Y,

J. A. Kaduk; W. Wong-Ng; B. H. Toby; W. Greenwood; J. Dillingham

1999-01-01

86

Cross-section measurement of the 169 Tm p,n reaction for the production of the therapeutic radionuclide 169 Yb and comparison with its reactor-based generation.  

PubMed

The radionuclide (169)Yb (T(1/2)=32.0 d) is potentially important for internal radiotherapy. It is generally produced using a nuclear reactor. In this work the possibility of its production at a cyclotron was investigated. A detailed determination of the excitation function of the (169)Tm(p,n)(169)Yb reaction was done over the proton energy range up to 45 MeV using the stacked-foil technique and high-resolution gamma-ray spectrometry. The integral yield of (169)Yb was calculated. Over the optimum energy range E(P)=16-->7 MeV the yield amounts to 1.5 MBq/micro Ah and is thus rather low. A comparison of this production route with the established (168)Yb(n,gamma)(169)Yb reaction at a nuclear reactor is given. The (169)Yb yield via the reactor route is by several orders of magnitude higher than by the cyclotron method. The latter procedure, however, leads to "no-carrier-added" product. PMID:15919210

Spahn, I; Takács, S; Shubin, Yu N; Tárkányi, F; Coenen, H H; Qaim, S M

2005-08-01

87

A quantum chemistry investigation on the structure of lanthanide triflates Ln(OTf)3 where Ln = La, Ce, Nd, Eu, Gd, Er, Yb and Lu.  

PubMed

Density functional theory has been used to probe the electronic structure, coordination number, optical properties and the vibration spectra of monolanthanide trifluoromethane sulfonate Ln(OTf)(3) complexes where Ln = La, Ce, Nd, Eu, Gd, Er, Yb and Lu. The study reveals that the OTf group is bonded to Ln as a bidentate ligand. TDDFT calculations show that, for La(OTf)(3), MLTC and HOMO-LUMO transitions in the UV-vis are strongly bathochromically shifted compared to those of Lu(OTf)(3.). PMID:20354620

Hannachi, Douniazed; Ouddai, Nadia; Chermette, Henry

2010-04-21

88

Upconversion luminescence properties of Yb3+ and Tm3+ codoped amorphous fluoride ZrF4-BaF2-LaF3-AlF3-NaF thin film prepared by pulsed laser deposition.  

PubMed

The Yb3+ and Tm3+ co-doped 55.98ZrF4-28BaF2-2.5LaF3-4AlF3-7NaF-2.5YbF3-0.02TmF3 amorphous fluoride film was prepared by pulsed laser deposition. The spectroscopic properties and energy transfer analysis of this film were studies in detail. Ultraviolet and visible upconversion emissions were observed under the infrared excitation at 980 nm. In comparison with that of its target, the upconversion emissions of the film in the visible and ultraviolet range were greatly enhanced. The possible energy transfer mechanism of the emissions was given to understand the upconversion process. This kind of thin films has potential applications for the integrated optical waveguide amplifier and ultraviolet laser. PMID:24734646

He, Chunfeng; Qin, Guanshi; Zhao, Dan; Chuai, Xiaohong; Wang, Lili; Zheng, Kezhi; Qin, Weiping

2014-05-01

89

Upconversion Nanophosphors Naluf4:Yb,Tm for Lymphatic Imaging In Vivo by Real-Time Upconversion Luminescence Imaging under Ambient Light and High-Resolution X-ray CT  

PubMed Central

Lanthanide upconversion nanophosphor (UCNP) has attracted increasing attention for potential applications in bioimaging due to its excellence in deep and high contrast imaging. To date, most upconversion imaging applications were demonstrated in dark surroundings without ambient light for higher signal-to-noise ratio, which hindered the application of optical imaging guided surgery. Herein, the new established NaLuF4-based UCNP (NaLuF4:Yb,Tm, ~17 nm) with bright upconversion emission around 800 nm as imaging signal was used to realize imaging under ambient light to provide more convenient for clinician. Moreover, due to the existance of heavy element lutetium (Lu) in the host lattice, the NaLuF4:Yb,Tm nanoparticles can also be used as an X-ray CT imaging agent to enhance the imaging depth and in vivo imaging resolution. PMID:23650481

Sun, Yun; Peng, Juanjuan; Feng, Wei; Li, Fuyou

2013-01-01

90

Structural and Magnetothermal Properties of Compounds: Yb5SixGe4-x,Sm5SixGe4-x, EuO, and Eu3O4  

SciTech Connect

The family of R{sub 5}Si{sub x}Ge{sub 4-x} alloys demonstrates a variety of unique physical phenomena related to magneto-structural transitions associated with reversible breaking and reforming of specific bonds that can be controlled by numerous external parameters such as chemical composition, magnetic field, temperature, and pressure. Therefore, R{sub 5}Si{sub x}Ge{sub 4-x} systems have been extensively studied to uncover the mechanism of the extraordinary magneto-responsive properties including the giant magnetoresistance (GMR) and colossal magnetostriction, as well as giant magnetocaloric effect (GMCE). Until now, more than a half of possible R{sub 5}Si{sub x}Ge{sub 4-x} pseudobinary systems have been completely or partially investigated with respect to their crystallography and phase relationships (R = La, Pr, Nd, Gd, Tb, Dy, Er, Lu, Y). Still, there are other R{sub 5}Si{sub x}Ge{sub 4-x} systems (R = Ce, Sm, Ho, Tm, and Yb) that are not studied yet. Here, we report on phase relationships and structural, magnetic, and thermodynamic properties in the Yb{sub 5}Si{sub x}Ge{sub 4-x} and Sm{sub 5}Si{sub x}Ge{sub 4-x} pseudobinary systems, which may exhibit mixed valence states. The crystallography, phase relationships, and physical properties of Yb{sub 5}Si{sub x}Ge{sub 4-x} alloys with 0 {le} x {le} 4 have been examined by using single crystal and powder x-ray diffraction at room temperature, and dc magnetization and heat capacity measurements between 1.8 K and 400 K in magnetic fields ranging from 0 to 7 T. Unlike the majority of R{sub 5}Si{sub x}Ge{sub 4-x} systems studied to date, where R is the rare earth metal, all Yb-based germanide-silicides with the 5:4 stoichiometry crystallize in the same Gd{sub 5}Si{sub 4}-type structure. The magnetic properties of Yb{sub 5}Si{sub x}Ge{sub 4-x} materials are nearly composition-independent, reflecting the persistence of the same crystal structure over the whole range of x from 0 to 4. Both the crystallographic and magnetic property data indicate that Yb{sub 5}Si{sub x}Ge{sub 4-x} alloys are mixed valence systems, in which the majority (60%) of Yb atoms is divalent, while the minority (40%) is trivalent. This finding is supported by recent Moessbauer spectroscopy data.

Kyunghan Ahn

2007-05-09

91

Interplay between Cu and Fe Valences in Ba R(Cu 0.5Fe 0.5) 2O 5+ ? Double Perovskites with R=Lu, Yb, Y, Eu, Sm, Nd, and Pr  

Microsoft Academic Search

We have conducted a systematic 57Fe Mössbauer study on BaR(Cu0.5Fe0.5)2O5+? double perovskites with various oxygen contents and rare-earth elements (R=Lu, Yb, Y, Eu, Sm, Nd, and Pr). In samples based on R=Lu, Yb, Y, Eu, Sm the oxygen content remained at ??0, upon reductive or oxidative heat treatments under normal pressure. The larger rare-earth elements, i.e. Nd or Pr, readily

J. Lindén; M. Kochi; K. Lehmus; T. Pietari; M. Karppinen; H. Yamauchi

2002-01-01

92

JOURNAL DE PHYSIQUE Collogue C5, supplement au n 5, Tome 40, Mai 1979, page C5-370 Valence changes and semiconductor-to-metal transitions in Tm^^Eu^Se and  

E-print Network

difference A£ between the two configurations 4f13 (Tm2+ ) and 4f12 5d(Tm3+ ) which determines the valenceJOURNAL DE PHYSIQUE Collogue C5, supplement au n° 5, Tome 40, Mai 1979, page C5-370 Valence changes and semiconductor-to-metal transitions in Tm^^Eu^Se and TmSei-^Te* B. Batlogg, E. Kaldis and P. Wachter Laboratorium

Boyer, Edmond

93

Thermoelectric transport properties of CaMg2Bi2, EuMg2Bi2, and YbMg2Bi2  

NASA Astrophysics Data System (ADS)

The thermoelectric transport properties of CaMg2Bi2, EuMg2Bi2, and YbMg2Bi2 were characterized between 2 and 650 K. As synthesized, the polycrystalline samples are found to have lower p-type carrier concentrations than single-crystalline samples of the same empirical formula. These low carrier concentration samples possess the highest mobilities yet reported for materials with the CaAl2Si2 structure type, with a mobility of ˜740 cm2/V/s observed in EuMg2Bi2 at 50 K. Despite decreases in the Seebeck coefficient (?) and electrical resistivity (?) with increasing temperature, the power factor (?2?) increases for all temperatures examined. This behavior suggests a strong asymmetry in the conduction of electrons and holes. The highest figure of merit (zT) is observed in YbMg2Bi2, with zT approaching 0.4 at 600 K for two samples with carrier densities of approximately 2×1018 cm-3 and 8×1018 cm-3 at room temperature. Refinements of neutron powder diffraction data yield similar behavior for the structures of CaMg2Bi2 and YbMg2Bi2, with smooth lattice expansion and relative expansion in c being ˜35% larger than relative expansion in a at 973 K. First-principles calculations reveal an increasing band gap as Bi is replaced by Sb and then As, and subsequent Boltzmann transport calculations predict an increase in ? for a given n associated with an increased effective mass as the gap opens. The magnitude and temperature dependence of ? suggests higher zT is likely to be achieved at larger carrier concentrations, roughly an order of magnitude higher than those in the current polycrystalline samples, which is also expected from the detailed calculations.

May, Andrew F.; McGuire, Michael A.; Singh, David J.; Ma, Jie; Delaire, Olivier; Huq, Ashfia; Cai, Wei; Wang, Hsin

2012-01-01

94

Ultraviolet-driven white light generation from oxyfluoride glass co-doped with Tm{sup 3+}-Tb{sup 3+}-Eu{sup 3+}  

SciTech Connect

Tm{sup 3+}-Tb{sup 3+}-Eu{sup 3+} co-doped oxyfluoride glasses, doped with about 3.0 mol. % TmF{sub 3}, 0.25 mol. % TbF{sub 3}, and 0.25 mol. % EuF{sub 3}, have been prepared by melt quenching technique. Under excitation at commercial 365 nm, the rare-earth co-dopants are all directly excited and emit in the blue, green, and red, respectively, without appreciable energy transfer amongst the co-dopants. Tint of the white luminescence can be adjusted by changing the ratio of the co-dopants. Properties of the glass host promote excellent dissolution of the co-dopants and low non-radiative decay rate. The white emission at 365 nm excitation is suitable for light emitting diodes applications.

Kuznetsov, A. S.; Nikitin, A.; Tikhomirov, V. K.; Shestakov, M. V.; Moshchalkov, V. V. [INPAC-Institute for Nanoscale Physics and Chemistry, KULeuven, Celestijnenlaan 200D, Heverlee, 3001 Leuven (Belgium)] [INPAC-Institute for Nanoscale Physics and Chemistry, KULeuven, Celestijnenlaan 200D, Heverlee, 3001 Leuven (Belgium)

2013-04-22

95

Up-conversion emission tuning in triply-doped Yb3+/Tm3+/Er3+ novel fluoro-phosphate glass and glass-ceramics  

NASA Astrophysics Data System (ADS)

New Yb3+, Er3+ and Tm3+ triply doped fluoro-phosphate glasses belonging to the system NaPO3-YF3-BaF2-CaF2 have been prepared by the classical melt-casting technique. Glasses containing up to 10 wt.% of rare-earth ions fluorides have been obtained and characterized by using differential scanning calorimetry (DSC), UV-visible-near-infrared spectroscopy and up-conversion emission spectroscopy under excitation with a 975 nm laser diode. Transparent and optically homogeneous glass-ceramics have been reproducibly obtained by appropriate heat treatment in view to manage the red, green and blue emissions upon 975 nm laser excitation. According to the applied thermal heat-treatment, a large enhancement of intensity of the up-conversion emission - from 10 to 160 times higher - has been achieved in the glassceramics compared to that of glasses, suggesting incorporation of the rare-earth ions into the crystalline phase. Furthermore, a large range of color rendering has been observed in these materials by controlling the laser excitation power and material crystallization rate. Time-resolved luminescence experiments as well as X-ray diffractometry and scanning electron microscopy techniques have been employed in order to understand and correlate the multicolor emission changes to the crystallization behavior of this material. A progressive phase transformation of the fluorite-type CaF2-based nanocrystals initially generated was observed along with increasing heat-treatment time, thus modifying the rare earth ions spectroscopic features.

Ledemi, Yannick; Trudel, Andrée.-Anne; Rivera, Victor A. G.; Messaddeq, Younes

2014-03-01

96

Rare-Earths Centers (Sm{sup 3+}, Eu{sup 3+}, Yb{sup 3+}) in MeF{sub 2}(Me = Ca, Sr, Ba, Cd) Crystals  

SciTech Connect

Rare-earth elements RE{sup 3+}(RE = Sm, Eu, Yb) form impurity centers in fluorite-like crystals MeF{sub 2}(Me = Ca, Sr, Ba, Cd). The crystal structure of cubic, trigonal and tetragonal centers in MeF{sub 2} has been investigated in the framework of shell model and pair potential approximation. The crystal field parameters were calculated with the exchange charges model, using the optimized geometry of the doped host matrix. With these parameters we have been calculated the optical spectra and spin-Hamiltonian (g-factors) of RE{sup 3+} in MeF{sub 2}, for some combination of R{sup 3+} and MeF{sup 2}. The obtained results were discussed and comparison with experimental data was made. A good agreement confirms the method and model of calculations.

Nikiforov, A. E.; Chernyshev, V. A.; Volodin, V. P. [Ural State University, 620083-Ekaterinburg, Lenin av. 51 (Russian Federation); Avram, N. M. [West University of Timisoara, Dept. of Physics, 300223-Timisoara, Bd. V. Parvan No. 4 (Romania); Academy of Romanian Scientists, Independentei 54, 050094-Bucharest (Romania); Avram, C. N.; Vaida, M. [West University of Timisoara, Dept. of Physics, 300223-Timisoara, Bd. V. Parvan No. 4 (Romania)

2010-08-04

97

Structural and dielectric properties of Ba 2YbTaO 6, Ba 2YSbO 6 and Ba 2EuZrO 5.5  

NASA Astrophysics Data System (ADS)

Structural and dielectric properties of Ba 2YbTaO 6, Ba 2YSbO 6 and Ba 2EuZrO 5.5 perovskites are presented. Because these materials were suggested as prospective buffer layers and substrates for HTS electronic devices such as SIS structures etc., their chemical stability with YBa 2Cu 3O 7- ? (YBCO) and Bi 2Sr 2Ca nCu n+1 O x ( n = 1, 2; BiSCCO) was examined up to processing temperatures of listed superconductors. All three materials were found to be chemically stable with both YBCO and BiSCCO. Moreover, addition of ca. 20% of these perovskites to YBCO did not have any detrimental effect on the transition temperature. Dielectric properties of all a.m. materials were determined with high accuracy by measuring resonant frequencies of completely filled dielectric cavities at frequencies up to 40 GHz and at temperatures from 60 K to 350 K. The dielectric permittivities for particular materials are as follows: Ba 2YbTaO 6 ? ?? = 29.4; Ba 2EuZrO 5.5 ? ?? = 30.8; Ba 2YSbO 6 ? ?? = 13.5. In microwave range all materials exhibit low or moderate losses. However, at temperatures where HTS materials enter into superconducting state (80-130 K), they exhibit some unusual features (a kind of a phase transition), which may either help or hamper their suggested applications in HTS electronics [J. Konopka, I. Wolff, S.J. Lewandowski, J. Appl. Phys. 72 (1992) 218].

Konopka, Janusz; Jose, Rajan; Wo?cyrz, Marek

2006-03-01

98

Turn-On Detection of a Cancer Marker Based on Near-Infrared Luminescence Energy Transfer from NaYF4:Yb,Tm/NaGdF4 Core-Shell Upconverting Nanoparticles to Gold Nanorods.  

PubMed

A homogeneous immunoassay for the sensitive and selective determination of trace amounts of ?-fetoprotein (AFP, a cancer marker) by detection in the near-infrared (NIR) region based on luminescence energy transfer (LET) from NaYF4:Yb,Tm/NaGdF4 core-shell upconverting nanoparticles to gold nanorods (GNRs) is presented. The carboxyl-functionalized NaYF4:Yb,Tm/NaGdF4 core-shell upconverting nanoparticles (UCNPs) were excited by a 980 nm continuous wavelength laser, and its emission peak appeared at a near-infrared wavelength (?804 nm). The carboxyl-functionalized upconverting nanoparticles were conjugated with the anti-AFP (Ab1) and acted as donor. GNRs with a high absorption band around 790 nm, which was overlapped the UCNPs emission, were synthesized and acted as the acceptor. The donor (negatively charged) interacted with the acceptor (positively charged) via electrostatic interactions to bring them into close proximity. LET could occur, producing a quenching phenomenon. When the AFP antigens were added into the system, the binding affinity between AFP and Ab1 was stronger than the electrostatic interactions, which released the energy acceptors from the energy donors, interrupting luminescence energy transfer, and therefore, the luminescence was recovered. On the basis of the restored luminescence, a turn-on optical immunosening system was developed. Under the optimal conditions, the linear range of detection was from 0.18 to 11.44 ng/mL for AFP (R = 0.99), with a detection limit as low as 0.16 ng/mL. The proposed method has also been used to monitor AFP in human serum samples. Therefore, further study based on the NaYF4:Yb,Tm/NaGdF4 core-shell nanoparticles-GNRs construction may open the way for a new class of NIR-LET biosensors with wide applications. PMID:25296290

Chen, Hongqi; Guan, Yingying; Wang, Shaozhen; Ji, Yuan; Gong, Mengqi; Wang, Lun

2014-11-01

99

TmPd2Si2 and YbPd2Si2 : a Mssbauer effect study of crystal fields and intermediate valence  

E-print Network

énergie totale que l'on attend pour la configuration 2F 7/2 de Yb3+ (~ 100 K). L'état de valence/2 configuration (~ 100 K). The intermediate valence behaviour is observed on Yb in both the dilute" and 4f" - 15d rare earth electronic configurations enables electron transfer to occur between the 4f

Paris-Sud XI, Université de

100

Single-Component and Warm-White-Emitting Phosphor NaGd(WO4)2:Tm(3+), Dy(3+), Eu(3+): Synthesis, Luminescence, Energy Transfer, and Tunable Color.  

PubMed

Tm(3+), Dy(3+), and Eu(3+) codoped NaGd(WO4)2 phosphors were prepared by a facile hydrothermal process; they were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectrometer (EDS), photoluminescence spectra, and fluorescence lifetime. The results show that the novel octahedral microcrystals with a mean side length of 2 ?m are obtained. Under the excitation of ultraviolet, individual RE(3+) ion (Tm(3+), Dy(3+), and Eu(3+)) activated NaGd(WO4)2 phosphors exhibit excellent emission properties in their respective regions. Moreover, when codoping Dy(3+) and Eu(3+)/Tm(3+) in the single component, the energy migration from Dy(3+) to Eu(3+) has been demonstrated to be a resonant type via a dipole-quadrupole mechanism as well as that from Tm(3+) to Dy(3+) ions, of which the critical distance (RDy-Eu) is calculated to be 11.08 Å. More significantly, in the Tm(3+), Dy(3+), and Eu(3+) tridoped NaGd(WO4)2 phosphors, the energy migration of Tm(3+)-Dy(3+)-Eu(3+), utilized for sensitizing Eu(3+) ions besides compensating the red component at low Eu(3+) doping concentration, has been discussed first. In addition, under 365 nm near-ultraviolet radiation (nUV), the color-tunable emissions in octahedral NaGd(WO4)2 microcrystals are realized by giving abundant blue, green, white, yellow, and red emissions, especially warm white emission, and could be favorable candidates in full-color phosphors for nUV-LEDs. PMID:25303406

Liu, Yan; Liu, Guixia; Wang, Jinxian; Dong, Xiangting; Yu, Wensheng

2014-11-01

101

Red persistent and photo-stimulated luminescence properties of SrCaSi5N8: Eu2+, Tm3+ solid solution  

NASA Astrophysics Data System (ADS)

The red persistent and photo-stimulated luminescent (PSL) nitride phosphor, SrCaSi5N8: Eu2+, Tm3+ solid solution, had been synthesized through conventional high temperature solid-state reaction. The SrCaSi5N8: Eu2+, Tm3+ phosphor shows strong photoluminescence (PL) and weak PSL (?em = 647 nm), both originating from the 4f65d-4f7 transition of Eu2+. Thermoluminescence (TL) glow curves measured at various stimulating conditions (UV excitation, in dark, laser stimulation after UV irradiation) show the same peak positions at 345 K and 360 K but great differences in the intensities. The afterglow decay curve presents excellent long-lasting red phosphorescence with a decay time of 30 min (?0.32 mcd/m2) after turning off the activating light. Moreover, the laser stimulated luminescence spectra, which feature sharp rising and falling edges (monitored at 647 nm) as the infrared laser diode (980 nm) excitation was turned on and off periodically, exhibit interesting rapidly responsive, erasable and rewritable abilities.

Wang, Jin; Zhang, Haoran; Lei, Bingfu; Dong, Hanwu; Zhang, Haiming; Liu, Yingliang; Lai, Nuolin; Fang, Yun; Chen, Zhijie

2014-09-01

102

Separation of the contributions to the magnetization of Tm{sub 1-x}Yb{sub x}B{sub 12} solid solutions in steady and pulsed magnetic fields  

SciTech Connect

The magnetization of substitutional Tm{sub 1-x}Yb{sub x}B{sub 12} solid solutions is studied in the composition range 0 < x {<=} 0.81. The measurements are performed at low temperatures (1.9-300 K) in steady (up to 11 T) and pulsed (up to 50 T, pulse duration of 20-100 ms) magnetic fields. An analysis of the experimental data allowed the contributions to the magnetization of the paramagnetic phase of the Tm{sub 1-x}Yb{sub x}B{sub 12} compounds to be separated. These contributions include a Pauli component, which corresponds to the response of the heavy-fermion manybody states that appears in the energy gap in the vicinity of the Fermi level (density of states (3-4) Multiplication-Sign 10{sup 21} cm{sup -3} meV{sup -1}), and a contribution with saturation in high magnetic fields attributed to the localized magnetic moments ((0.8-3.7){mu}{sub B} per unit cell) of the nanoclusters formed by rare-earth ions with an antiferromagnetic interaction.

Bogach, A. V., E-mail: alex@lt.gpi.ru; Sluchanko, N. E.; Glushkov, V. V.; Demishev, S. V.; Azarevich, A. N.; Filippov, V. B. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Shitsevalova, N. Yu.; Levchenko, A. V. [National Academy of Sciences of Ukraine, Institute of Problems of Materials Science (Ukraine); Vanacken, J.; Moshchalkov, V. V. [Katholieke Universiteit Leuven, Institute of Nanoscale Physics and Chemistry (Belgium); Gabani, S.; Flachbart, K. [Slovak Academy of Sciences, Institute of Experimental Physics (Slovakia)

2013-05-15

103

Electrochemical and spectroscopic investigation of Ln3+ (Ln = Sm, Eu, and Yb) solvation in bis(trifluoromethylsulfonyl)imide-based ionic liquids and coordination by N,N,N',N'-tetraoctyl-3-oxa-pentane diamide (TODGA) and chloride.  

PubMed

The electrochemistry and electronic absorption spectroscopy of samarium, europium, and ytterbium were investigated in the 1-(1-butyl)trimethylammonium bis(trifluoromethylsulfonyl)imide (BuMe3NTf2N) and 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BuMePyroTf2N) ionic liquids and in these solvents containing the neutral tridentate ligand N,N,N',N'-tetraoctyl-3-oxo-pentane diamide (TODGA) and the anionic hard ligand chloride. Lanthanide ions were introduced into the ionic liquids by controlled potential oxidation of the respective metals to yield solutions containing Eu(2+), Sm(3+), and Yb(3+), and it was possible to cycle between Eu(2+) and Eu(3+) as well as Yb(3+) and Yb(2+) using controlled potential electrolysis. Electronic absorption spectroscopy suggested that the Ln(3+) species are weakly solvated by Tf2N(-) anions as [Ln(Tf2N)x]((x-3)-) in the neat ILs. The quasireversible Ln(3+/2+) couples of all three elements were readily accessible in these ILs, but Sm(2+) was only stable on the voltammetric time scale. Addition of TODGA to [Ln(Tf2N)x]((x-3)-) solutions produces 3:1 complexes with Eu(3+) and Sm(3+) but only a 2:1 complex with the smaller Yb(3+) ion. Depending on the temperature, addition of Cl(-) to solutions of [Ln(Tf2N)x]((x-3)-) induces precipitation of LnCl3(s) when the mole ratio mCl(-)/mLn(3+) ? 3. However, when mCl(-)/mLn(3+) > 3, these precipitates redissolve to form the octahedral chloride complexes, [LnCl6](3-). PMID:23439132

Pan, Yunfeng; Hussey, Charles L

2013-03-18

104

The high-pressure synthesis and characterization of some praseodymium-substituted rare-earth-based RâBaâCuâO{sub 14-δ} (R = Nd, Eu, Tm)  

Microsoft Academic Search

The formation of phases in the (R{sub 1-x}Prâ)âBaâCuâO{sub 14+δ} (Pr-doped R247; R = Nd, Eu, Tm) system with x = 0-1.0 was investigated. Samples of the title series were synthesized at 980-990°C at 25 bar Oâ, followed by annealing at 300°C under 130 bar Oâ for 30 hr. Oxygen content of the samples has been determined by iodometric titration. Single-phased

Teng-Ming Chen; F. S. Kao

1997-01-01

105

Observation of superconductivity at 30?46K in AxFe2Se2 (A = Li, Na, Ba, Sr, Ca, Yb, and Eu)  

PubMed Central

New iron selenide superconductors by intercalating smaller-sized alkali metals (Li, Na) and alkaline earths using high-temperature routes have been pursued ever since the discovery of superconductivity at about 30?K in KFe2Se2, but all have failed so far. Here we demonstrate that a series of superconductors with enhanced Tc = 30?46?K can be obtained by intercalating metals, Li, Na, Ba, Sr, Ca, Yb, and Eu in between FeSe layers by the ammonothermal method at room temperature. Analysis on their powder X-ray diffraction patterns reveals that all the main phases can be indexed based on body-centered tetragonal lattices with a?3.755–3.831 Å while c?15.99–20.54 Å. Resistivities show the corresponding sharp transitions at 45?K and 39?K for NaFe2Se2 and Ba0.8Fe2Se2, respectively, confirming their bulk superconductivity. These findings provide a new starting point for studying the properties of these superconductors and an effective synthetic route for the exploration of new superconductors as well. PMID:22645642

Ying, T. P.; Chen, X. L.; Wang, G.; Jin, S. F.; Zhou, T. T.; Lai, X. F.; Zhang, H.; Wang, W. Y.

2012-01-01

106

Highly uniform and monodisperse GdOF:Ln3+ (Ln = Eu, Tb, Tm, Dy, Ho, Sm) microspheres: hydrothermal synthesis and tunable-luminescence properties.  

PubMed

GdOF:Ln(3+) (Ln = Eu, Tb, Tm, Dy, Ho and Sm) microspheres (1.5 ?m) with high uniformity and monodispersity have been synthesized via a facile hydrothermal method followed by heat treatment (600 °C). X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), as well as photoluminescence (PL) and cathodoluminescence (CL) spectra are used to characterize the resulting samples. A series of controlled experiments indicate that sodium citrate (Cit(3-)) as a shape modifier introduced into the reaction system plays a critical role in the shape evolution of the final products. Furthermore, the shape and size of the products can be further manipulated by adjusting the dosage of Cit(3-) and pH values in the initial solution. The possible formation mechanism for these microspheres has been presented. Under UV light and low-voltage electron beam excitation, GdOF:Ln(3+) microspheres show the characteristic f-f transitions of Ln(3+) (Eu, Tb/Ho, Tm, Dy and Sm) ions and give bright red, green, blue, yellow and yellowish-orange emission, respectively. In addition, multicolored luminescence containing white emission have been successfully confected for co-doped GdOF:Ln(3+) phosphors by changing the doped Ln(3+) ions and adjusting their doping concentrations due to the simultaneous luminescence of Ln(3+) in the GdOF host, making these materials have potential applications in field-emission display devices. PMID:23942823

Zhang, Yang; Kang, Xiaojiao; Geng, Dongling; Shang, Mengmeng; Wu, Yuan; Li, Xuejiao; Lian, Hongzhou; Cheng, Ziyong; Lin, Jun

2013-10-21

107

Crystal structures of RPt{sub 3-x}Si{sub 1-y}(R=Y, Tb, Dy, Ho, Er, Tm, Yb) studied by single crystal X-ray diffraction  

SciTech Connect

The crystal structures of ternary compounds RPt{sub 3-x}Si{sub 1-y}(R=Y, Tb, Dy, Ho, Er, Tm, Yb) have been elucidated from X-ray single crystal CCD data. All compounds are isotypic and crystallize in the tetragonal space group P4/mbm. The general formula RPt{sub 3-x}Si{sub 1-y} arises from defects: x{approx}0.20, y{approx}0.14. The crystal structure of RPt{sub 3-x}Si{sub 1-y} can be considered as a packing of four types of building blocks which derive from the CePt{sub 3}B-type unit cell by various degrees of distortion and Pt, Si-defects. - Graphical Abstract: Electron density in RPt{sub 3-x}Si{sub 1-y} at 0, 1/2 , 0.

Gribanov, Alexander [Institute of Physical Chemistry, University of Vienna, Waehringerstrasse 42, A-1090 Wien (Austria); Chemistry Department of the Moscow State University, Leninskie Gory, GSP-1, 119991 Moscow (Russian Federation); Grytsiv, Andriy [Institute of Physical Chemistry, University of Vienna, Waehringerstrasse 42, A-1090 Wien (Austria); Rogl, Peter, E-mail: peter.franz.rogl@univie.ac.a [Institute of Physical Chemistry, University of Vienna, Waehringerstrasse 42, A-1090 Wien (Austria); Seropegin, Yurii [Chemistry Department of the Moscow State University, Leninskie Gory, GSP-1, 119991 Moscow (Russian Federation); Giester, Gerald [Institute of Mineralogy and Crystallography, University of Vienna, Althanstrasse 14, A-1090 Wien (Austria)

2009-07-15

108

The High-Pressure Synthesis and Characterization of Some Praseodymium-Substituted Rare-Earth-Based R2Ba 4Cu 7O 14+ ?( R=Nd, Eu, Tm)  

NASA Astrophysics Data System (ADS)

The formation of phases in the ( R1- xPr x) 2Ba 4Cu 7O 14+ ?(Pr-doped R247; R=Nd, Eu, Tm) system with x=0-1.0 was investigated. Samples of the title series were synthesized at 980-990°C at 25 bar O 2, followed by annealing at 300°C under 130 bar O 2for 30 hr. Oxygen content of the samples has been determined by iodometric titration. Single-phased samples were obtained with xsmaller than or equal to 0.3, 0.4, and 0.4 for R=Nd, Eu, and Tm, respectively, as indicated by X-ray diffraction measurements. With increasing amount of Pr substituting for R, the cell dimensions of the Pr-doped R247 phases were found to expand steadily, whereas the corresponding structural orthorhombicity was observed to decrease systematically. Superconducting transition temperatures ( Tc's) of the title phases were found to be significantly suppressed upon Pr doping, as indicated by field-cooled temperature-dependent magnetization studies. The effect of Pr substitution on Tc's of R247 ( R=Y, Eu, Er, Tm, Nd, Dy) phases was investigated and compared as a function of R3+radii, but no size dependence effect was observed. In addition, field-dependent magnetization studies for a series of (Eu 1- xPr x) 2Ba 4Cu 7O 14+ ?samples with x=0, 0.2, and 0.4, respectively, are also reported.

Chen, Teng-Ming; Kao, F. S.

1997-08-01

109

Evolution of the crystal and magnetic structure of the R2MnRuO7 (R = Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y) family of pyrochlore oxides.  

PubMed

The members of the family of pyrochlore oxides with the formula R(2)MnRuO(7) (R = Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) have been synthesized and characterized. Polycrystalline samples were prepared by a soft chemistry procedure involving citrates of the different metal ions, followed by thermal treatments in air or O(2) pressure. The crystallographic and magnetic structures have been analysed from X-ray diffraction (XRD) and neutron powder diffraction (NPD) data, in complement with magnetic measurements; the evolution along the series of the crystallographic parameters (unit-cell parameters, bond distances and angles) is discussed. In R(2)MnRuO(7) pyrochlores, Mn and Ru ions statistically occupy the 16c sites in a cubic unit cell with space group Fd ?3m, which defines an intrinsic frustrated three-dimensional system. In all the cases, the low-temperature NPD data unveils an antiferromagnetic coupling of two subsets of Mn(4+)/Ru(4+) spins, indicating that the magnetic frustration is partially relieved by the random distribution of Mn and Ru over the 16c sites. At lower temperatures there is a polarization of the R(3+) magnetic moments, which also participate in the magnetic structure, when a magnetic rare earth is present. PMID:22669397

Martínez-Coronado, R; Retuerto, M; Fernández, M T; Alonso, J A

2012-07-28

110

Correlation between slow magnetic relaxation and the coordination structures of a family of linear trinuclear Zn(II)-Ln(III)-Zn(II) complexes (Ln = Tb, Dy, Ho, Er, Tm and Yb).  

PubMed

Six linear trinuclear [Ln{Zn(L)(AcO)}(2)]BPh(4) complexes (H(2)L denotes the Schiff-base ligand formed by a condensation reaction between ethylenediamine and two equivalents of o-vanillin), including Ln = Tb (1), Dy (2), Ho (3), Er (4), Tm (5) and Yb (6) were synthesized and were confirmed to be isostructural via X-ray crystallographic analyses. The Ln(III) ion in each complex is deca-coordinated by four equatorial oxygen donors from the methoxo groups of the Schiff-base ligands, two oxygen donors from the acetate anions and four axial oxygen donors from the phenoxo groups of the Schiff-base ligands. AC susceptibility measurements, with an oscillating frequency of 10 to 10,000 Hz, revealed that 1, 2, 4 and 6 show slow magnetic relaxation under a 1000 Oe DC bias field, which occurs via a single process, as confirmed by the semi-circular Cole-Cole plots. These complexes are considered to be field-induced single-molecule magnets under these conditions. The presence or absence of the slow magnetic relaxation process is discussed by correlating the characteristic magnetic anisotropy of each Ln(III) ion with the ligand field anisotropy. PMID:22898750

Maeda, Moe; Hino, Shiori; Yamashita, Kei; Kataoka, Yumiko; Nakano, Motohiro; Yamamura, Tomoo; Kajiwara, Takashi

2012-11-28

111

Enhanced dual contrast agent, Co(2+)-doped NaYF4:Yb(3+),Tm(3+) nanorods, for near infrared-to-near infrared upconversion luminescence and magnetic resonance imaging.  

PubMed

Dual-modality imaging with magnetic resonance (MR) and upconversion luminescence (UCL) is a promising technique for molecular imaging in biomedical research. Multifunctional lanthanide-based nanoparticles have been widely investigated as agents for contrast enhanced MR and fluorescence imaging. However, the use of rare earth fluoride nanoparticles for dual-modality imaging of T2-weighted MR and UCL is rarely reported. We find that NaYF4:Yb(3+),Tm(3+),Co(2+) (MUC) nanorods can be applied as a high-performance dual contrast agent for both T2-weighted MR and UCL dual-modality imaging. After modification with 6-O-carboxymethyl chitosan (OCC), MUC nanorods can be endocytosed by cells without showing signs of cytotoxicity. High-quality UCL images of living cells incubated with MUC-OCC nanorods were acquired on a near-infrared (NIR) confocal microscopy under the excitation at 980 nm. Moreover, MUC-OCC nanorods display high transverse (r2) relaxivities in vitro. The application of low-dose MUC-OCC nanorods for NIR-to-NIR UCL and MR dual-modality in vivo imaging was also carried out successfully. In addition, the toxicity of MUC-OCC nanorods was evaluated by MTT assay, serological tests and histological analysis of visceral organs. PMID:25108318

Xia, Ao; Zhang, Xiaofeng; Zhang, Jun; Deng, Yunyun; Chen, Qiang; Wu, Shishan; Huang, Xiaohua; Shen, Jian

2014-11-01

112

Ce{sub 2}AgYb{sub 5/3}Se{sub 6}, La{sub 2}CuErTe{sub 5}, and Ce{sub 2}CuTmTe{sub 5}: Three new quaternary interlanthanide chalcogenides  

SciTech Connect

Three new ordered quaternary interlanthanide chalcogenides, Ce{sub 2}AgYb{sub 5/3}Se{sub 6}, La{sub 2}CuErTe{sub 5}, and Ce{sub 2}CuTmTe{sub 5}, have been prepared by direct reaction of the elements in molten NaBr at 900 Degree-Sign C. Each compound forms a new structure-type. The Ce{sub 2}AgYb{sub 5/3}Se{sub 6} structure consists of {infinity}{sup 2}{l_brace} [AgYb{sub 5/6}Se{sub 6}]{sup 6-}{r_brace} layers intercalated by Ce{sup 3+} cations. These layers are composed of {infinity}{sup 1}{l_brace} [Yb{sub 5/3}Se{sub 6}]{sup 7-}{r_brace} quadruplet ribbons of [YbSe{sub 6}]{sup 9-} octahedra and infinite {infinity}{sup 1}{l_brace} [AgSe{sub 6}]{sup 11-}{r_brace} double chains of [AgSe{sub 5}]{sup 9-}. The La{sub 2}CuErTe{sub 5} structure is made of one-dimensional {infinity}{sup 1}{l_brace} [CuErTe{sub 5}]{sup 6-}{r_brace} ribbons separated by La{sup 3+} cations. These ribbons are formed by cis-edge sharing {infinity}{sup 1}{l_brace} [CuTe{sub 2}]{sup 3-}{r_brace} tetrahedral chains and trans-edge sharing {infinity}{sup 1}{l_brace} [ErTe{sub 4}]{sup 5-}{r_brace} chains. While La{sub 2}CuErTe{sub 5} crystallizes in the orthorhombic space group Pnma, Ce{sub 2}CuTmTe{sub 5} crystallizes in the monoclinic space group C2/m. The latter crystal structure is assembled from {infinity}{sup 2}{l_brace} [CuTmTe{sub 5}]{sup 6-}{r_brace} layers intercalated by Ce{sup 3+} cations. These layers consist of single {infinity}{sup 1}{l_brace} [TmTe{sub 4}]{sup 5-}{r_brace} chains connected to each other through dimers or pseudo-double chains. - Graphical abstract: [CuTe{sub 4}]{sup 7-} tetrahedra sharing cis-edges to yield chains in the La{sub 2}CuErTe{sub 5}. Highlights: Black-Right-Pointing-Pointer New ordered interlanthanide tellurides. Black-Right-Pointing-Pointer New quaternary chalcogenides. Black-Right-Pointing-Pointer Low-dimensional lanthanide chalcogenide substructures. Black-Right-Pointing-Pointer Flux synthesis of new chalcogenides.

Babo, Jean-Marie [Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, IN 46556 (United States); Albrecht-Schmitt, Thomas E., E-mail: talbrec1@nd.edu [Department of Chemistry and Biochemistry, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States)

2013-01-15

113

The high-pressure synthesis and characterization of some praseodymium-substituted rare-earth-based R{sub 2}Ba{sub 4}Cu{sub 7}O{sub 14-{delta}} (R = Nd, Eu, Tm)  

SciTech Connect

The formation of phases in the (R{sub 1-x}Pr{sub x}){sub 2}Ba{sub 4}Cu{sub 7}O{sub 14+{delta}} (Pr-doped R247; R = Nd, Eu, Tm) system with x = 0-1.0 was investigated. Samples of the title series were synthesized at 980-990{degree}C at 25 bar O{sub 2}, followed by annealing at 300{degree}C under 130 bar O{sub 2} for 30 hr. Oxygen content of the samples has been determined by iodometric titration. Single-phased samples has been determined by iodometric titration. Single-phased samples were obtained with x smaller than or equal to 0.3, 0.4, and 0.4 for R = Nd, Eu, and Tm, respectively, as indicated by X-ray diffraction measurements. With increasing amount of Pr substituting for R, the cell dimensions of the Pr-doped R247 phases were found to expand steadily, whereas the corresponding structural orthorhombicity was observed to decrease systematically. Superconducting transition temperatures (T{sub c}`s) of the title phases were found to be significantly suppressed upon Pr doping, as indicated by field-cooled temperature-dependent magnetization studies. The effect of Pr substitution on T{sub c}`s of R247 (R = Y, Eu, Er, Tm, Nd, Dy) phases was investigated and compared as a function of R{sup 3+} radii, but no size dependence effect was observed. In addition, field-dependent magnetization studies for a series of (Eu{sub 1-x}Pr{sub x}){sub 2}Ba{sub 4}Cu{sub 7}O{sub 14+{delta}} samples with x = 0, 0.2, and 0.4, respectively, are also reported.

Teng-Ming Chen; Kao, F.S. [National Chiao-Tung Univ., Taiwan (China)

1997-08-01

114

Two new ternary lanthanide antimony chalcogenides: Yb{sub 4}Sb{sub 2}S{sub 11.25} and Tm{sub 4}Sb{sub 2}Se{sub 11.68} containing chalcogenide Q{sup 2-} and dichalcogenide (Q{sub 2}){sup 2-} anions  

SciTech Connect

Dark red and dark brown crystals of Yb{sub 4}Sb{sub 2}S{sub 11.25} and Tm{sub 8}Sb{sub 4}Se{sub 11.68}, respectively, were obtained from the reaction of the elements in Sb{sub 2}Q{sub 3} (Q=S, Se) fluxes. Both non-stoichiometric compounds are orthorhombic and crystallize in the same space group Pnnm, with two formula units per unit cell (a=12.446(2), b=5.341(1), c=12.058(2) for sulfide and a=13.126(2), b=5.623(1), c=12.499(2) for the selenide). Their crystal structures are dominated by lanthanide-chalcogenide polyhedra (CN=7 and 8), which share corners, edges, triangular- and square-faces to form a three-dimensional framework embedding antinomy cations. The latter are coordinated by three sulfide anions with 5(1+2+2) secondary contacts forming basically infinite chains running along [0 1 0]. The chalcogens in both compounds form chalcogenide Q{sup 2-} and dichalcogenide (Q{sub 2}){sup 2-} anionic units. The optical analysis made on those compounds shows that both are semiconductors with band gap of 1.71 and 1.22 eV for Yb{sub 4}Sb{sub 2}S{sub 11.25} and Tm{sub 4}Sb{sub 2}Se{sub 11.75,} respectively. - Graphical Abstract: The crystal structure of Yb{sub 4}Sb{sub 2}S{sub 11} viewed along the [0 1 0]. Highlights: Black-Right-Pointing-Pointer Lanthanide chalcogenides. Black-Right-Pointing-Pointer Semiconductors. Black-Right-Pointing-Pointer Tunnel structures. Black-Right-Pointing-Pointer Lone-pair effects.

Babo, Jean-Marie [Department of Civil Engineering and Geological Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Albrecht-Schmitt, Thomas E., E-mail: talbrec1@nd.edu [Department of Civil Engineering and Geological Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States)

2012-03-15

115

A systematic study of the photophysical processes in polydentate triphenylene-functionalized Eu3+, Tb3+, Nd3+, Yb3+, and Er3+ complexes  

Microsoft Academic Search

m-Terphenyl-based lanthanide complexes functionalized with a triphenylene antenna chromophore ((Ln)1) exhibit sensitized visible and near-infrared emission upon photoexcitation of the triphenylene antenna at 310 nm. Luminescence lifetime measurements of the (Eu)1 and (Tb)1 complexes in methanol-h1 and methanol-d1 revealed that one methanol molecule is coordinated to the lanthanide ion, indicating that all eight donor atoms provided by the ligand are

Stephen I. Klink; Lennart Grave; David N. Reinhoudt; Veggel van Frank C. J. M; Martinus H. V. Werts; Frank A. J. Geurts; Johannes W. Hofstraat

2000-01-01

116

Four new lanthanide-nitronyl nitroxide (Ln(III) = Pr(III), Sm(III), Eu(III), Tm(III)) complexes and a Tb(III) complex exhibiting single-molecule magnet behavior.  

PubMed

Five new complexes based on rare-earth-radical [Ln(hfac)(3)(NIT-5-Br-3py)](2) (Ln = Pr (1), Sm (2), Eu (3), Tb (4), Tm (5); hfac = hexafluoroacetylacetonate; NIT-5-Br-3py = 2-(4,4,5,5-tetramethyl-3-oxylimidazoline-1-oxide)-5-bromo-3-pyridine) have been synthesized and characterized by X-ray crystal diffraction. The single-crystal structures show that these complexes have similar structures, in which a NIT-5-Br-3py molecule acts as a bridging ligand linking two Ln(III) ions through the oxygen atom of the N-O group and nitrogen atom from the pyridine ring to form a four-spin system. Both static and dynamic magnetic properties were measured for complex 4, which exhibits single-molecule magnetism behavior. PMID:19691302

Xu, Jin-Xia; Ma, Yue; Liao, Dai-zheng; Xu, Gong-Feng; Tang, Jinkui; Wang, Chao; Zhou, Na; Yan, Shi-Ping; Cheng, Peng; Li, Li-Cun

2009-09-21

117

Materials Science and Engineering B105 (2003) 9196 Photoluminescence studies of rare earth (Er, Eu, Tm) in situ doped GaN  

E-print Network

doping of wide band-gap semiconductors such as GaN, AlN, and SiC has led to the observation of intense RE, Tm) in situ doped GaN U. Hömmericha,, Ei Ei Nyeina, D.S. Leeb, J. Heikenfeldb, A.J. Stecklb, J The emission properties of rare earth (RE)-doped GaN are of significant current interest for applications

Steckl, Andrew J.

118

Heteroleptic Lanthanide Compounds with Chalcogenolate Ligands: Reduction of PhNNPh/ PhEEPh (E ) Se or Te) Mixtures with Ln (Ln ) Ho, Er, Tm, Yb). Thermolysis Can Give  

E-print Network

reduce mixtures of azobenzene and PhEEPh (E ) Se or Te) in pyridine to give the bimetallic compounds [(py), Yb (8)). The structures of [(py)2Er(µ-2-2-PhNNPh)(SePh)]2,2py (2) and [(py)2Ho(µ-2-2-PhNNPh)- (TePh)]2,2py (5) have been determined by low-temperature single-crystal X-ray diffraction, and the nearly

Lawson, Catherine L.

119

Re-dispersion and film formation of GdVO4?:? Ln3+ (Ln3+ = Dy3+, Eu3+, Sm3+, Tm3+) nanoparticles: particle size and luminescence studies.  

PubMed

GdVO(4)?:?Ln(3+) (Ln(3+) = Dy(3+), Eu(3+), Sm(3+), Tm(3+)) nanoparticles are prepared by a simple chemical route at 140 °C. The crystallite size can be tuned by varying the pH of the reaction medium. Interestingly, the crystallite size is found to increase significantly when pH increases from 6 to 12. This is related to slower nucleation of the GdVO(4) formation with increase of VO(4)(3-) present in solution. The luminescence study shows an efficient energy transfer from vanadate absorption of GdVO(4) to Ln(3+) and thereby enhanced emissions are obtained. A possible reaction mechanism at different pH values is suggested in this study. As-prepared samples are well dispersed in ethanol, methanol and water, and can be incorporated into polymer films. Luminescence and its decay lifetime studies confirm the decrease in non-radiative transition probability with the increase of heat treatment temperature. Re-dispersed particles will be useful in potential applications of life science and the film will be useful in display devices. PMID:22334276

Shanta Singh, N; Ningthoujam, R S; Phaomei, Ganngam; Singh, S Dorendrajit; Vinu, A; Vatsa, R K

2012-04-21

120

TM report  

NASA Technical Reports Server (NTRS)

Key spectral, radiometric, and geometric characteristics of the TM sensor are examined. Spectrally, band 5 is slightly wider than specified and its upper edge at 50% of miximum of 1784 nm includes some unintended overlap with water absorption bands. Thermal band 6 is half the expected width. Radiometrically, the TM has extreme linearity and stability in comparison with previous MSS photomultiplier systems. Forward and reverse scans on TM show some unexplained radiometric differences of up to four digital levels. Primary focal plane bands show a monotomic decrease in gain of about 5% in the five months since launch. The relative internal gains of bands 5 and 7 varied with a period of about 60 days and an amplitude of about 6%. Radiometric calibration must be applied before histogram equalization algorithms to preserve radiometric accuracy. Geometrically, channel 4 in band 2 has a smaller modulation transfer function than desired. There is apparent misregistration of .75 pixels along scan and 0.2 pixels across scan.

Barker, J. L.

1983-01-01

121

Triaxial strongly deformed bands in {sup 160,161}Tm  

SciTech Connect

High-spin states in {sup 160,161}Tm were populated using the {sup 128}Te({sup 37}Cl, 5n and 4n) reactions at a beam energy of 170 MeV. Emitted {gamma} rays were detected in the Gammasphere spectrometer. Two rotational bands with high moments of inertia were discovered, one assigned to {sup 160}Tm, while the other tentatively assigned to {sup 161}Tm. These sequences display features similar to bands observed in neighboring Er, Tm, Yb, and Lu nuclei which have been discussed in terms of triaxial strongly deformed structures. Cranked Nilsson Strutinsky calculations have been performed that predict well-deformed triaxial shapes at high spin in {sup 160,161}Tm.

Teal, C.; Lagergren, K.; Aguilar, A.; Riley, M. A. [Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States); Hartley, D. J. [Department of Physics, U.S. Naval Academy, Annapolis, Maryland 21402 (United States); Simpson, J.; Joss, D. T. [STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Carpenter, M. P.; Janssens, R. V. F.; Lauritsen, T.; Lister, C. J.; Zhu, S. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Garg, U. [Physics Department, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Kondev, F. G. [Nuclear Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Wang, X. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Physics Department, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Ragnarsson, I. [Division of Mathematical Physics, LTH, Lund University, P.O. Box 118, S-22100 Lund (Sweden)

2008-07-15

122

Electronic Configuration of Yb Compounds  

Microsoft Academic Search

The total energy differences between divalent and trivalent configurations of Yb ions in a number of Yb compounds are studied. Two different band theoretical methods, which differ in the treatment of the localized f electrons, are used. The results show that in all Yb compounds the valence energy differences are equal to the energy needed to localize an f electron.

W. M. Temmerman; Z. Szotek; A. Svane; P. Strange; H. Winter; A. Delin; B. Johansson; O. Eriksson; L. Fast; J. M. Wills

1999-01-01

123

EU Business  

NSDL National Science Digital Library

EU Business is provided by Europanet. It aims to provide selected business information to the busy business person. Information available at the site includes European Union (EU) law, business developments in Europe, finance and EU programs. The site also keeps track of European Commission proposals and the progress of draft legislation. Users interested in doing business in Europe will find this site a useful guide to facilitate the process.

1998-01-01

124

A dosimetric comparison of {sup 169}Yb versus {sup 192}Ir for HDR prostate brachytherapy  

SciTech Connect

For the purpose of evaluating the use of {sup 169}Yb for prostate High Dose Rate brachytherapy (HDR), a hypothetical {sup 169}Yb source is assumed with the exact same design of the new microSelectron source replacing the {sup 192}Ir active core by pure {sup 169}Yb metal. Monte Carlo simulation is employed for the full dosimetric characterization of both sources and results are compared following the AAPM TG-43 dosimetric formalism. Monte Carlo calculated dosimetry results are incorporated in a commercially available treatment planning system (SWIFT{sup TM}), which features an inverse treatment planning option based on a multiobjective dose optimization engine. The quality of prostate HDR brachytherapy using the real {sup 192}Ir and hypothetical {sup 169}Yb source is compared in a comprehensive analysis of different prostate implants in terms of the multiobjective dose optimization solutions as well as treatment quality indices such as Dose Volume Histograms (DVH) and the Conformal Index (COIN). Given that scattering overcompensates for absorption in intermediate photon energies and distances in the range of interest to prostate HDR brachytherapy, {sup 169}Yb proves at least equivalent to {sup 192}Ir irrespective of prostate volume. This has to be evaluated in view of the shielding requirements for the {sup 169}Yb energies that are minimal relative to that for {sup 192}Ir.

Lymperopoulou, G.; Papagiannis, P.; Sakelliou, L.; Milickovic, N.; Giannouli, S.; Baltas, D. [Nuclear and Particle Physics Section, Physics Department, University of Athens, Panepistimioupolis, Ilisia, 157 71 Athens (Greece); Department of Medical Physics and Engineering, Strahlenklinik, Klinikum Offenbach, 63069 Offenbach (Germany); Pi-Medical Ltd., Research and Development Dept., Gennimata 2 Str., 115 24, Ampelokipoi, Athens (Greece); Department of Medical Physics and Engineering, Strahlenklinik, Klinikum Offenbach, 63069 Offenbach (Germany) and Nuclear and Particle Physics Section, Physics Department, University of Athens, Panepistimioupolis, Ilisia, 157 71 Athens (Greece)

2005-12-15

125

Edinburgh Research Explorer The Structure of Eu-III  

E-print Network

-filled and filled 4f shells, respectively. As a result, Eu and Yb both exhibit a significantly larger atomic volume than would be expected to be consistent with the general trend observed within the lanthanide series [1]. They also do not follow the general trend of phase transitions under pressure or with increasing atomic

Millar, Andrew J.

126

The series of rare earth complexes [Ln2Cl6 (?-4,4'-bipy)(py)6], Ln=Y, Pr, Nd, Sm-Yb: a molecular model system for luminescence properties in MOFs based on LnCl3 and 4,4'-bipyridine.  

PubMed

A series of 12 dinuclear complexes [Ln2Cl6(?-4,4'-bipy)(py)6], Ln=Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, (1-12, respectively) was synthesized by an anhydrous solvothermal reaction in pyridine. The complexes contain a 4,4'-bipyridine bridge and exhibit a coordination sphere closely related to luminescent lanthanide MOFs based on LnCl3 and 4,4-bipyridine. The dinuclear complexes therefore function as a molecular model system to provide a better understanding of the luminescence mechanisms in the Ln-N-MOFs (?)(2)[Ln2Cl6(4,4'-bipy)3]·2(4,4'-bipy). Accordingly, the luminescence properties of the complexes with Ln=Y, Sm, Eu, Gd, Tb, Dy, (1, 4-8) were determined, showing an antenna effect through a ligand-metal energy transfer. The highest efficiency of luminescence is observed for the terbium-based compound 7 displaying a high quantum yield (QY of 86%). Excitation with UV light reveals typical emission colors of lanthanide-dependent intra 4f-4f-transition emissions in the visible range (Tb(III) : green, Eu(III) : red, Sm(III) : salmon red, Dy(III) : yellow). For the Gd(III)- and Y(III)-containing compounds 6 and 1, blue emission based on triplet phosphorescence is observed. Furthermore, ligand-to-metal charge-transfer (LMCT) states, based on the interaction of Cl(-) with Eu(III), were observed for the Eu(III) compound 5 including energy-transfer processes to the Eu(III) ion. Altogether, the model complexes give further insights into the luminescence of the related MOFs, for example, rationalization of Ln-independent quantum yields in the related MOFs. PMID:24243814

Matthes, Philipp R; Nitsch, Jörn; Kuzmanoski, Ana; Feldmann, Claus; Steffen, Andreas; Marder, Todd B; Müller-Buschbaum, Klaus

2013-12-16

127

Rare earth-copper-magnesium compounds RECu 9Mg 2 ( RE=Y, La-Nd, Sm-Ho, Yb) with ordered CeNi 3-type structure  

NASA Astrophysics Data System (ADS)

A series of ternary compounds RECu 9Mg 2 ( RE=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb) have been synthesized via induction melting of elemental metal ingots followed by annealing at 400 °C for 4 weeks. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDXS) was used for examining microstructure and phase composition. These phases crystallize with an ordered version of the binary hexagonal structure type first reported for CeNi 3. The crystal structure was solved for TbCu 9Mg 2 from single crystal X-ray counter data (TbCu 9Mg 2-structure type, P6 3/mmc-space group, hP24-Pearson symbol, a=0.49886 (7) nm, c=1.61646 (3) nm, RF=0.0474 for 190 unique reflections). The Rietveld refinement of the X-ray powder diffraction patterns of RECu 9Mg 2 confirmed the same crystal structure for the reported rare earth metals. The unit cell volumes for RECu 9Mg 2 smoothly follow the lanthanide contraction. The existence of a RECu 9Mg 2 phase was excluded for RE=Er and Tm under the investigated experimental conditions.

Solokha, P.; Pavlyuk, V.; Saccone, A.; De Negri, S.; Prochwicz, W.; Marciniak, B.; Ró?ycka-Soko?owska, E.

2006-10-01

128

Valences of dopants in Eu2+ persistent luminescence materials  

NASA Astrophysics Data System (ADS)

The existence and effect of different rare earth (R2+/3+/IV) ions in SrAl2O4:Eu2+,R3+ and M2MgSi2O7:Eu2+,R3+ (M: Sr, Ba) persistent luminescence materials was studied with XANES (x-ray absorption near edge structure) measurements at HASYLAB/DESY (Hamburg, Germany) and MAX-lab (Lund, Sweden). The experiments were carried out at 298 K for selected rare earth (co-)dopants (Eu2+; Ce3+, Nd3+, Sm3+, Dy3+ and Yb3+). The co-existence of Eu2+ and Eu3+ was observed in all materials. The co-dopants were always in the trivalent form.

Lastusaari, M.; Brito, H. F.; Carlson, S.; Hölsä, J.; Laamanen, T.; Rodrigues, L. C. V.; Welter, E.

2014-04-01

129

Bose-Einstein Condensation of Yb atoms  

SciTech Connect

We could recently achieve the Bose Einstein condensation (BEC) of Yb atoms. Yb differs from most of the elements that have previously been condensed, because it is a two-electron atom with the singlet S ground state. Furthermore the Bosonic isotopes of Yb, like 174Yb which we succeeded to condensate, has no nuclear spin, so that the ground state is completely spin-less state and hence insensitive to magnetic fields. Thus a new type of atom could join the group of atoms for BEC studies. We would like to report how we could achieve the BEC of Yb atoms.

Takasu, Y.; Maki, K.; Komori, K.; Takano, T.; Honda, K.; Kumakura, M.; Yabuzaki, T.; Takahashi, Y. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

2005-05-05

130

Highly Efficient Tm-Doped Yttrium Aluminum Garnet Ceramic Laser Based on the Novel Fiber-Bulk Hybrid Configuration  

NASA Astrophysics Data System (ADS)

A polycrystalline ceramic Tm3+-doped yttrium aluminum garnet (Tm:Y3Al5O12, Tm:YAG) laser based on the novel fiber-bulk hybrid configuration is demonstrated using a high-power and tunable Er,Yb co-doped fiber laser as the pump source. Lasing characteristics of a 4.0 at. % Tm:YAG ceramic are investigated at different pump wavelengths from 1617 to 1625 nm. With an output coupler of 10% transmission, a maximum output power of 3.9 W is obtained at 2013.2 nm under an 8.8 W incident pump power at the Tm:YAG absorption peak of 1620.4 nm, corresponding to a slope efficiency of 50.1% with respect to the incident pump power.

Liu, Jun; Shen, Deyuan; Huang, Haitao; Zhang, Xiaoqi; Tang, Dingyuan; Fan, Dianyuan

2013-09-01

131

GEOMAG[TM] Paradoxes  

ERIC Educational Resources Information Center

As often happens, a lot of physics can come out of a toy. What we found interesting is the observation of the magnetic field produced by different configurations built with GEOMAG[TM]. This toy provides small magnetic bars and steel spheres to play with. Amusing 3-D structures can be built; nevertheless, this possibility is not so obvious. Indeed,…

Defrancesco, Silvia; Logiurato, Fabrizio; Karwasz, Grzegorz

2007-01-01

132

Gd(3+)-Yb(3+) Exchange Interactions in LiYb(x)Y(1-x)F4 Single Crystals.  

National Technical Information Service (NTIS)

The evaluated Gd(3+) -Yb(3+) exchange interactions over the nearest and the next-nearest neighbors in LiYb(x)Y(1-x)F4 are found to increase in parabolic manner with x, the concentration of Yb(3+) ions. The Gd(3+) -Yb(3+) exchange interactions are sensitiv...

L. E. Misiak

2001-01-01

133

Different evolution of the intrinsic gap in strongly correlated SmB6 in contrast to YbB12  

NASA Astrophysics Data System (ADS)

Dependence of the spectral functions near the Fermi level on temperature and rare-earth atom doping was studied in detail for strongly correlated alloys Sm1-xEuxB6 and Yb1-xLuxB12 by photoelectron spectroscopy at ˜8000 eV as well as at 7 and 8.4 eV. It was found that the 4f lattice coherence and intrinsic gap are robust for Sm1-xEuxB6 at least up to the Eu substitution of x = 0.15 while both collapse by Lu substitution already at x = 0.125 for Yb1-xLuxB12. As for the temperature dependence of the spectral shapes near the Fermi level at low temperatures, rather contrasting results were observed between YbB12 and SmB6. Although the gap shape does not change below 15 K for YbB12 with the characteristic temperature T* of 80 K, the spectral shape of SmB6 with a T* of 140 K shows that the peak beyond the gap is further increased below 15 K. The temperature dependence of the spectra near the intrinsic gap is clearly different between SmB6 and YbB12, although both materials have so far been categorized in the same kind of strongly correlated semiconductor. The possibility of the surface contribution is discussed for SmB6.

Yamaguchi, J.; Sekiyama, A.; Kimura, M. Y.; Sugiyama, H.; Tomida, Y.; Funabashi, G.; Komori, S.; Balashov, T.; Wulfhekel, W.; Ito, T.; Kimura, S.; Higashiya, A.; Tamasaku, K.; Yabashi, M.; Ishikawa, T.; Yeo, S.; Lee, S.-I.; Iga, F.; Takabatake, T.; Suga, S.

2013-04-01

134

Unconventional T-H Phase Diagram in the Noncentrosymmetric Compound Yb2Fe12P7  

NASA Astrophysics Data System (ADS)

The temperature-(T-)magnetic-field (H) phase diagram for the noncentrosymmetric compound YbFeP, determined from electrical resistivity (?), specific heat (C), and magnetization (M) measurements on single crystal specimens, is reported. This system exhibits a crossover from a magnetically ordered non-Fermi-liquid (NFL) phase at low H to another NFL phase at higher H. The crossover occurs near the value of H where the magnetic ordering temperature (TM) is no longer observable in C(T,H)/T and ?(T,H), but not where TM extrapolates smoothly to T=0K at a possible quantum critical point (QCP). This indicates the occurrence of a quantum phase transition between the two NFL phases. The lack of a clear relationship between the extrapolated QCP and NFL behavior suggests an unconventional route to the NFL ground states.

Baumbach, R. E.; Hamlin, J. J.; Shu, L.; Zocco, D. A.; O'Brien, J. R.; Ho, P.-C.; Maple, M. B.

2010-09-01

135

CW laser performance of Yb and Er,Yb doped tungstates  

Microsoft Academic Search

.  ?Room temperature cw laser action of Yb3+-doped KY(WO4)2 and KGd(WO4)2 crystals at 1.025 ?m and Er,?Yb?:?KY(WO4)2 at 1.54 ?m has been demonstrated under pumping by both Ti-sapphire laser and InGaAs laser diodes. A slope efficiency of Yb-lasers\\u000a up to 78% has been obtained.

N. V. Kuleshov; A. A. Lagatsky; V. G. Shcherbitsky; V. P. Mikhailov; E. Heumann; T. Jensen; A. Diening; G. Huber

1997-01-01

136

NanoKids(TM)  

NSDL National Science Digital Library

NanoKids(TM) is an education and outreach program for intermediate-level (middle-school) students intended to increase their knowledge of nanotechnology and emerging research and technology in this field, which involves working with objects on the molecular and atomic scale (as small as one-billionth of a meter). Site materials include a series of self-contained lessons accompanied by animated videos and an online workbook for students. There is also a sample test and additional resources for teachers (slide presentations, games, and other materials). The site also offers an overview of the project and its participants, biographical "sketches" of the characters used in the animations, and one-page features that explain the nanometer scale, the countries and scientists involved in nanotechnology, and atoms, molecules, and bondng. Some materials on the site are available in Spanish.

137

Powerful green Yb-doped fiber laser  

NASA Astrophysics Data System (ADS)

A powerful Yb-doped fiber laser with intra-cavity frequency doubling in KTP nonlinear crystal has been realized. Green output power of 1 W level has been achieved at ~ 11W of multimode laser diode pump power.

Akulov, V. A.; Babin, S. A.; Churkin, D. V.; Kablukov, S. I.; Vlasov, A. A.

2007-06-01

138

Phase equilibrium and intermediate phases in the Eu-Sb system  

SciTech Connect

Rapid heating rate thermal analysis, X-ray diffraction, fluorescence spectrometry, and differential dissolution method were used to study the high-temperature phase equilibrium in the Eu-Sb system within the composition range between 37 and 96 at% Sb. The techniques were effective in determination of the vapor-solid-liquid equilibrium since intermediate phases except Eu{sub 4}Sb{sub 3} evaporated incongruently after melting. A thermal procedure was developed to determine the liquidus and solidus lines of the T-x diagram. Six stable phases were identified: two phases, EuSb{sub 2} and Eu{sub 4}Sb{sub 3}, melt congruently at 1045{+-}10 deg. C and 1600{+-}15 deg. C, the Eu{sub 2}Sb{sub 3}, Eu{sub 11}Sb{sub 10}, Eu{sub 5}Sb{sub 4}, and Eu{sub 5}Sb{sub 3} phases melt incongruently at 850{+-}8 deg. C, 950{+-}10 deg. C, 1350{+-}15 deg. C, and 1445{+-}15 deg. C, respectively. The exact composition shifting of Sb-rich decomposable phases towards Eu{sub 4}Sb{sub 3}, the most refractory compound, was determined. The topology of the Eu-Sb phase diagram was considered together with that of the Yb-Sb system. - Graphical abstract: The high-temperature range of the T-x phase diagram for the Eu-Sb system. Highlights: > The phase relations in the Eu-Sb system were studied over a large composition and temperature scale. > The liquidus and solidus lines of the T-x diagram were well established using effective techniques. > In the system, six binary phases are stable and they melt incongruently except EuSb{sub 2} and Eu{sub 4}Sb{sub 3}. > Incongruent evaporation was found to be typical of all the phases besides Eu{sub 4}Sb{sub 3}.

Abdusalyamova, M.N. [Institute of Chemistry of Tajik Academy of Sciences, Ajni Str. 299/2, 734063 Dushanbe (Tajikistan); Vasilyeva, I.G., E-mail: kamarz@niic.nsc.ru [Nikolaev Institute of Inorganic Chemistry, Russian Academy of Sciences, Siberian Branch, Lavrentiev Avenue, 3, 630090 Novosibirsk (Russian Federation)

2011-10-15

139

Monodisperse lanthanide oxyfluorides LnOF (Ln = Y, La, Pr-Tm): morphology controlled synthesis, up-conversion luminescence and in vitro cell imaging.  

PubMed

Lanthanide oxyfluorides LnOF (Ln = Y, La, Pr-Tm) nano/micro-materials with a variety of well-defined morphologies including nanorods, nanospindles, nanorod-bundles and nanospheres, have been successfully synthesized via a facile precipitation technique followed by a heating treatment. It is found that the pH values, fluoride sources and dosage of urea in the initial reaction systems play critical roles in the morphology determination of the LnOF products and the possible formation mechanism for these diverse architectures has been presented. XRD, FT-IR, TG-DTA, SEM, TEM, as well as up-conversion (UC) luminescence spectra are used to characterize the synthesized samples. Under 980 nm NIR laser excitation, red, green and blue UC luminescence are observed from Yb(3+)/Er(3+), Yb(3+)/Ho(3+) and Yb(3+)/Tm(3+) co-doped YOF nanospheres. The MTT assay indicates that YOF nanospheres exhibit good biocompatibility. Especially, the emission spectrum of YOF: 0.20Yb(3+), 0.04Er(3+) nanospheres is dominated by a single red emission at 660 nm, which falls into the "optical window" of biological tissues. The application of YOF: 0.20Yb(3+), 0.04Er(3+) nanospheres in the cell imaging is also investigated, which shows a bright-red emission without background noise. PMID:24827577

Zhang, Yang; Li, Xuejiao; Hou, Zhiyao; Lin, Jun

2014-06-21

140

Definition of an intramolecular Eu-to-Eu energy transfer within a discrete [Eu2L] complex in solution.  

PubMed

Ligand L, based on two do3a moieties linked by the methylene groups of 6,6'-dimethyl-2,2'-bipyridine, was synthesized and characterized. The addition of Ln salts to an aqueous solution of L (0.01?M Tris-HCl, pH?7.4) led to the successive formation of [LnL] and [Ln(2)L] complexes, as evidenced by UV/Vis and fluorescence titration experiments. Homodinuclear [Ln(2)L] complexes (Ln = Eu, Gd, Tb, Yb, and Lu) were prepared and characterized. The (1)H and (13)C?NMR spectra of the Lu and Yb complexes in D(2)O solution (pD = 7.0) showed C(1) symmetry of these species in solution, pointing to two different chemical environments for the two lanthanide cations. The analysis of the chemical shifts of the Yb complex indicated that the two coordination sites present square antiprismatic (SAP) coordination environments around the metal ions. The spectroscopic properties of the [Tb(2)L] complex upon ligand excitation revealed conventional behavior with ?(H2O) = 2.05(1)?ms and ?(H2O) = 51%, except for the calculation of the hydration number obtained from the luminescent lifetimes in H(2)O and D(2)O, which pointed to a non-integer value of 0.6 water molecules per Tb(III) ion. In contrast, the Eu complex revealed surprising features such as: 1)?the presence of two and up to five components in the (5)D(0)?(7)F(0) and (5)D(0)?(7)F(1) emission bands, respectively; 2)?marked differences between the normalized spectra obtained in H(2)O and D(2)O solutions; and 3)?unconventional temporal evolution of the luminescence intensity at certain wavelengths, the intensity profile first displaying a rising step before the occurrence of the expected decay. Additional spectroscopic experiments performed on [Gd(2-x)Eu(x)L] complexes (x = 0.1 and 1.9) confirmed the presence of two distinct Eu sites with hydration numbers of 0 (site I) and 2 (site II), and showed that the unconventional temporal evolution of the emission intensity is the result of an unprecedented intramolecular Eu-to-Eu energy-transfer process. A mathematical model was developed to interpret the experimental data, leading to energy-transfer rates of 0.98?ms(-1) for the transfer from the site with q=0 to that with q=2 and vice versa. Hartree-Fock (HF) and density functional theory (DFT) calculations performed at the B3LYP level were used to investigate the conformation of the complex in solution, and to estimate the intermetallic distance, which provided Förster radii (R(0)) values of 8.1?Å for the energy transfer from site I to site II, and 6.8?Å for the reverse energy transfer. These results represent the first evidence of an intramolecular energy-transfer equilibrium between two identical lanthanide cations within a discrete molecular complex in solution. PMID:22614945

Nonat, Aline; Regueiro-Figueroa, Martín; Esteban-Gómez, David; de Blas, Andrés; Rodríguez-Blas, Teresa; Platas-Iglesias, Carlos; Charbonnière, Loïc J

2012-06-25

141

Quality of the rare earth aluminum borate crystals for laser applications, probed by high-resolution spectroscopy of the Yb3+ ion  

NASA Astrophysics Data System (ADS)

A comparative study was performed of the low-temperature high-resolution absorption spectra of the Yb3+ probe in R1-xYbxAl3(BO3)4 (R = Y, Tm, Lu) crystals grown by flux technique independently in four different laboratories using different solvents. We show that the incorporation of solvent components into the crystal in the course of crystallization gives rise to spectral satellites of the Yb3+ 0(2F7/2) ? 0'(2F5/2) absorption lines and assign particular satellites to the Yb3+ centers near the bismuth and molybdenum impurities (which decrease the transparency of YAB in the UV spectral range). We suggest this spectroscopic method for a rapid analysis of the quality of UV laser crystals and for improvement of growth technologies.

Boldyrev, K. N.; Popova, M. N.; Bettinelli, M.; Temerov, V. L.; Gudim, I. A.; Bezmaternykh, L. N.; Loiseau, P.; Aka, G.; Leonyuk, N. I.

2012-09-01

142

Low temperature magnetism in YbPtBi by {sup 170}Yb Moessbauer spectroscopy  

SciTech Connect

The authors report on {sup 170}Yb Moessbauer spectroscopy data in the cubic fcc alloy YbPtBi, in the temperature range 0.06--30 K. The zero field spectra show a two component structure above 1.5 K, which can be analyzed as due to 85% of Yb{sup 3+} ions at a site with cubic symmetry and 15% at a site with non-cubic symmetry. Below 0.3 K, the spectra are resolved and can also be interpreted in terms of two sites, but with a dominant non-cubic site ({approximately} 60%) with Yb ions bearing small magnetic moments. The spectra with a large applied magnetic field give information on the Yb{sup 3+} C.E.F. level scheme and on the exchange interaction. The relation of the Moessbauer data with the results of {micro}SR measurements is discussed.

Le Bras, G.; Bonville, P.; Hodges, J.A.; Imbert, P. [C.E. Saclay, Gif-sur-Yvette (France); Canfield, P.C. [Ames Lab., IA (United States)

1994-05-24

143

Anomalies in the Young modulus at structural phase transitions in rare-earth cobaltites RBaCo{sub 4}O{sub 7} (R = Y, Tm-Lu)  

SciTech Connect

The elastic properties of rare-earth cobaltites RBaCo{sub 4}O{sub 7} (R = Y, Tm-Lu) have been experimentally studied in the temperature range of 80-300 K. The strong softening of the Young modulus {Delta}E(T)/E{sub 0} Almost-Equal-To -(0.1-0.2) of cobaltites with Lu and Yb ions has been revealed, which is due to the instability of the crystal structure upon cooling and is accompanied by an inverse jump at the second-order structural phase transition. The softening of the Young modulus and the jump at the phase transition decrease by an order of magnitude and the transition temperature T{sub s} and hysteresis {Delta}T{sub s} increase from a compound with Lu to that with Tm. A large softening of the Young modulus at the structural transition in Lu- and Yb cobaltites indicates that the corresponding elastic constant goes to zero, whereas this constant in Tm cobaltite is not a 'soft' mode of the phase transition. It has been found that the structural phase transition in Lu- and Yb cobaltites is accompanied by a large absorption maximum at the phase transition point and an additional maximum in the low-temperature phase and absorption anomalies in Tm cobaltite is an order of magnitude smaller.

Kazei, Z. A., E-mail: kazei@plms.phys.msu.ru; Snegirev, V. V.; Andreenko, A. S. [Moscow State University (Russian Federation); Kozeeva, L. P. [Russian Academy of Sciences, Nikolaev Institute of Inorganic Chemistry, Siberian Branch (Russian Federation)

2011-08-15

144

Monodisperse lanthanide oxyfluorides LnOF (Ln = Y, La, Pr-Tm): morphology controlled synthesis, up-conversion luminescence and in vitro cell imaging  

NASA Astrophysics Data System (ADS)

Lanthanide oxyfluorides LnOF (Ln = Y, La, Pr-Tm) nano/micro-materials with a variety of well-defined morphologies including nanorods, nanospindles, nanorod-bundles and nanospheres, have been successfully synthesized via a facile precipitation technique followed by a heating treatment. It is found that the pH values, fluoride sources and dosage of urea in the initial reaction systems play critical roles in the morphology determination of the LnOF products and the possible formation mechanism for these diverse architectures has been presented. XRD, FT-IR, TG-DTA, SEM, TEM, as well as up-conversion (UC) luminescence spectra are used to characterize the synthesized samples. Under 980 nm NIR laser excitation, red, green and blue UC luminescence are observed from Yb3+/Er3+, Yb3+/Ho3+ and Yb3+/Tm3+ co-doped YOF nanospheres. The MTT assay indicates that YOF nanospheres exhibit good biocompatibility. Especially, the emission spectrum of YOF: 0.20Yb3+, 0.04Er3+ nanospheres is dominated by a single red emission at 660 nm, which falls into the ``optical window'' of biological tissues. The application of YOF: 0.20Yb3+, 0.04Er3+ nanospheres in the cell imaging is also investigated, which shows a bright-red emission without background noise.Lanthanide oxyfluorides LnOF (Ln = Y, La, Pr-Tm) nano/micro-materials with a variety of well-defined morphologies including nanorods, nanospindles, nanorod-bundles and nanospheres, have been successfully synthesized via a facile precipitation technique followed by a heating treatment. It is found that the pH values, fluoride sources and dosage of urea in the initial reaction systems play critical roles in the morphology determination of the LnOF products and the possible formation mechanism for these diverse architectures has been presented. XRD, FT-IR, TG-DTA, SEM, TEM, as well as up-conversion (UC) luminescence spectra are used to characterize the synthesized samples. Under 980 nm NIR laser excitation, red, green and blue UC luminescence are observed from Yb3+/Er3+, Yb3+/Ho3+ and Yb3+/Tm3+ co-doped YOF nanospheres. The MTT assay indicates that YOF nanospheres exhibit good biocompatibility. Especially, the emission spectrum of YOF: 0.20Yb3+, 0.04Er3+ nanospheres is dominated by a single red emission at 660 nm, which falls into the ``optical window'' of biological tissues. The application of YOF: 0.20Yb3+, 0.04Er3+ nanospheres in the cell imaging is also investigated, which shows a bright-red emission without background noise. Electronic supplementary information (ESI) available: The XRD patterns of GdOF, ErOF, Tm(OF)1.93 and YOF obtained after calcinations at 800 °C for 3 h and the corresponding standard data of GdOF, ErOF, Tm(OF)1.93 and YOF. The accurate amounts of Ln3+ and F- for LaOF, GdOF, ErOF and YOF: 0.20Yb3+, 0.04Er3+, respectively. SEM images of the ErOF precursor under different experimental conditions (a) pH = 2, urea/Ln3+ = 66, with LiF; (b) pH = 2, urea/Ln3+ = 66, with KF; (c) pH = 6, urea/Ln3+ = 66, with NaF; (d) pH = 10, urea/Ln3+ = 66, with NaF; (e) pH = 2, urea/Ln3+ = 80, with NaF and (f) pH = 2, urea/Ln3+ = 100, with NaF. See DOI: 10.1039/c4nr00384e

Zhang, Yang; Li, Xuejiao; Hou, Zhiyao; Lin, Jun

2014-05-01

145

LiquichekTM Diabetes Control  

E-print Network

LiquichekTM Diabetes Control Bio-Rad Laboratories D I A B E T E S / H E M O G L O B I N C O N T R O L S #12;LiquichekTM Diabetes Control Hemoglobin A1C Hemoglobin, Total A liquid human whole blood based product designed to monitor the performance of hemoglobin tests associated with diabetes

Rodriguez, Carlos

146

IEEE Std 1394bTM-2002 (Amendment to IEEE Std 1394TM-1995)  

E-print Network

IEEE Std 1394bTM-2002 (Amendment to IEEE Std 1394TM-1995) IEEEStandards 1394bTM IEEE Standard, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. IEEE Std 1394bTM -2002 (Amendment to IEEE Std 1394TM -1995) IEEE Standard for a High-Performance Serial Bus

Borgonovo, Flaminio

147

Lattice dynamics in the thermoelectric Zintl compound Yb[subscript 14]MnSb[subscript 11  

SciTech Connect

The density of phonon states in the thermoelectric material Yb{sub 14}MnSb{sub 11} has been studied first by inelastic neutron scattering and second in an element-specific way by nuclear inelastic x-ray scattering. The low sound velocity of 1880(50) m/s as obtained from the density of phonon states can be identified as an important reason for the low heat transport in this system. The high melting temperature of Yb{sub 14}MnSb{sub 11} contrasts with the low energy of all phonons (<25 meV) and relates to an unusual lack of softening of phonon modes with temperature, when comparing the phonon density of states observed at ambient temperatures and at 1200 K. We have also measured the density of phonon states of the related Eu{sub 14}MnSb{sub 11} compound and of the thermoelectric Zintl phase Zn{sub 4}Sb{sub 3} in order to compare with related thermodynamic properties of Yb{sub 14}MnSb{sub 11} and to elucidate the different mechanisms of the heat conductivity reduction in Zintl phases.

Möchel, A.; Sergueev, I.; Wille, H.-C.; Juranyi, F.; Schober, H.; Schweika, W.; Brown, S.R.; Kauzlarich, S.M.; Hermann, R.P. (DESY); (UCD); (Julich); (ILL); (ESRF); (ETH Zurich)

2012-04-02

148

Enhanced performance of Cr,Yb:YAG microchip laser by bonding Yb:YAG crystal.  

PubMed

Highly efficient, laser-diode pumped Yb:YAG/Cr,Yb:YAG self-Q-switched microchip lasers by bonding Yb:YAG crystal have been demonstrated for the first time to our best knowledge. The effect of transmission of output coupler (T(oc)) on the enhanced performance of Yb:YAG/Cr,Yb:YAG microchip lasers has been investigated and found that the best laser performance was achieved with T(oc) = 50%. Slope efficiency of over 38% was achieved. Average output power of 0.8 W was obtained at absorbed pump power of 2.5 W; corresponding optical-to-optical efficiency of 32% was obtained. Laser pulses with pulse width of 1.68 ns, pulse energy of 12.4 ?J, and peak power of 7.4 kW were obtained. The lasers oscillated in multi-longitudinal modes. The wide separation of longitudinal modes was attributed to the mode selection by combined etalon effect of Cr,Yb:YAG, Yb:YAG thin plates and output coupler. Stable periodical pulse trains at different pump power levels have been observed owing to the longitudinal modes coupling and competition. PMID:23187245

Cheng, Ying; Dong, Jun; Ren, Yingying

2012-10-22

149

Laser demonstration with highly doped Yb:Gd2O3 and Yb:Y2O3 crystals  

E-print Network

Laser demonstration with highly doped Yb:Gd2O3 and Yb:Y2O3 crystals grown by an original flux demonstration of an Yb-doped Gd2O3 cubic crystal. This crystal was obtained by the flux method using an original borate-based solvent, which was particularly well suited to the growth of rare earth sesquioxide crystals

150

TmDOTA-Tetraglycinate Encapsulated Liposomes as pH-Sensitive LipoCEST Agents  

PubMed Central

Lanthanide DOTA-tetraglycinate (LnDOTA-(gly)4?) complexes contain four magnetically equivalent amide protons that exchange with protons of bulk water. The rate of this base catalyzed exchange process has been measured using chemical exchange saturation transfer (CEST) NMR techniques as a function of solution pH for various paramagnetic LnDOTA-(gly)4? complexes to evaluate the effects of lanthanide ion size on this process. Complexes with Tb(III), Dy(III), Tm(III) and Yb(III) were chosen because these ions induce large hyperfine shifts in all ligand protons, including the exchanging amide protons. The magnitude of the amide proton CEST exchange signal differed for the four paramagnetic complexes in order, Yb>Tm>Tb>Dy. Although the Dy(III) complex showed the largest hyperfine shift as expected, the combination of favorable chemical shift and amide proton CEST linewidth in the Tm(III) complex was deemed most favorable for future in vivo applications where tissue magnetization effects can interfere. TmDOTA-(gly)4? at various concentrations was encapsulated in the core interior of liposomes to yield lipoCEST particles for molecular imaging. The resulting nanoparticles showed less than 1% leakage of the agent from the interior over a range of temperatures and pH. The pH versus amide proton CEST curves differed for the free versus encapsulated agents over the acidic pH regions, consistent with a lower proton permeability across the liposomal bilayer for the encapsulated agent. Nevertheless, the resulting lipoCEST nanoparticles amplify the CEST sensitivity by a factor of ?104 compared to the free, un-encapsulated agent. Such pH sensitive nano-probes could prove useful for pH mapping of liposomes targeted to tumors. PMID:22140438

Opina, Ana Christina L.; Ghaghada, Ketan B.; Zhao, Piyu; Kiefer, Garry; Annapragada, Ananth; Sherry, A. Dean

2011-01-01

151

CLEO 2007: CFJ -Yb Lasers Low-threshold On-chip Yb3+ Silica Laser  

E-print Network

:SiO2 Laser Testing · Fiber taper evanescently couples 972 nm pump light into and 1042 nm laser light · Microchip lasers - 71 mW 50 · Fiber lasers - 230 µW 500 · Ring type · Microtoroid - ? 10,000 · High QualityCLEO 2007: CFJ - Yb Lasers Low-threshold On-chip Yb3+ Silica Laser Eric Ostby, Lan Yang*, and Kerry

152

From Biology to DiscoveryTM LipodinAbTM  

E-print Network

. Several technologies based on the use of peptide transduction domain (PTD) were developed successfully to transduce proteins across the plasma membrane. However, these PTD poorly interact with proteins, and covalent linkage between the protein and PTD is most often required. LipodinAbTM is a formulation

Lebendiker, Mario

153

Neutron Resonance Parameters for Yb-171 (Ytterbium)  

NASA Astrophysics Data System (ADS)

This document is part of the Supplement containing the complete sets of data of Volume 24 `Neutron Resonance Parameters' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms'. It provides the neutron resonance parameters for the isotope Yb-171 (Ytterbium).

Sukhoruchkin, S. I.; Soroko, Z. N.

154

Study of encapsulated {sup 170}Tm sources for their potential use in brachytherapy  

SciTech Connect

Purpose: High dose-rate (HDR) brachytherapy is currently performed with {sup 192}Ir sources, and {sup 60}Co has returned recently into clinical use as a source for this kind of cancer treatment. Both radionuclides have mean photon energies high enough to require specific shielded treatment rooms. In recent years, {sup 169}Yb has been explored as an alternative for HDR-brachytherapy implants. Although it has mean photon energy lower than {sup 192}Ir, it still requires extensive shielding to deliver treatment. An alternative radionuclide for brachytherapy is {sup 170}Tm (Z=69) because it has three physical properties adequate for clinical practice: (a) 128.6 day half-life, (b) high specific activity, and (c) mean photon energy of 66.39 keV. The main drawback of this radionuclide is the low photon yield (six photons per 100 electrons emitted). The purpose of this work is to study the dosimetric characteristics of this radionuclide for potential use in HDR-brachytherapy. Methods: The authors have assumed a theoretical {sup 170}Tm cylindrical source encapsulated with stainless steel and typical dimensions taken from the currently available HDR {sup 192}Ir brachytherapy sources. The dose-rate distribution was calculated for this source using the GEANT4 Monte Carlo (MC) code considering both photon and electron {sup 170}Tm spectra. The AAPM TG-43 U1 brachytherapy dosimetry parameters were derived. To study general properties of {sup 170}Tm encapsulated sources, spherical sources encapsulated with stainless steel and platinum were also studied. Moreover, the influence of small variations in the active core and capsule dimensions on the dosimetric characteristics was assessed. Treatment times required for a {sup 170}Tm source were compared to those for {sup 192}Ir and {sup 169}Yb for the same contained activity. Results: Due to the energetic beta spectrum and the large electron yield, the bremsstrahlung contribution to the dose was of the same order of magnitude as from the emitted gammas and characteristic x rays. Moreover, the electron spectrum contribution to the dose was significant up to 4 mm from the source center compared to the photon contribution. The dose-rate constant {Lambda} of the cylindrical source was 1.23 cGy h{sup -1} U{sup -1}. The behavior of the radial dose function showed promise for applications in brachytherapy. Due to the electron spectrum, the anisotropy was large for r<6 mm. Variations in manufacturing tolerances did not significantly influence the final dosimetry data when expressed in cGy h{sup -1} U{sup -1}. For typical capsule dimensions, maximum reference dose rates of about 0.2, 10, and 2 Gy min{sup -1} would then be obtained for {sup 170}Tm, {sup 192}Ir, and {sup 169}Yb, respectively, resulting in treatment times greater than those for HDR {sup 192}Ir brachytherapy. Conclusions: The dosimetric characteristics of source designs exploiting the low photon energy of {sup 170}Tm were studied for potential application in HDR-brachytherapy. Dose-rate distributions were obtained for cylindrical and simplified spherical {sup 170}Tm source designs (stainless steel and platinum capsule materials) using MC calculations. Despite the high activity of {sup 170}Tm, calculated treatment times were much longer than for {sup 192}Ir.

Ballester, Facundo; Granero, Domingo; Perez-Calatayud, Jose; Venselaar, Jack L. M.; Rivard, Mark J. [Department of Atomic, Molecular and Nuclear Physics, University of Valencia, E-46100 Burjassot (Spain) and IFIC, CSIC, University of Valencia, E-46100 Burjassot (Spain); Department of Radiation Oncology, ERESA, Hospital General Universitario, E-46014 Valencia (Spain); Department of Radiation Oncology, La Fe University Hospital, E-46009 Valencia (Spain); Department of Medical Physics, Instituut Verbeeten, Tilburg 5000LA (Netherlands); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

2010-04-15

155

Listening and Legos[TM  

ERIC Educational Resources Information Center

This simple exercise, performed in teams, gives students practice in listening to instructions, particularly when there are restrictions for the communication. The teams compete in a limited amount of time to build a Lego[TM] structure based on the instructions of one team member. Which team listens the best and is most successful?

Morris, Pamela

2012-01-01

156

Tunability of Yb:glass laser  

NASA Astrophysics Data System (ADS)

Ytterbium doped phosphate glass (5 mol% of Yb2O3, thickness 1 and 2 mm, uncoated), developed for fibre laser, was tested in bulk form as a laser active medium. For Yb:glass pumping a fibre coupled (fibre core diameter 100 ?m, NA = 0.22) laser diode with emission at wavelength 975nm was used. The laser diode was operating in pulsed regime (pulse length 1.5 ms, repetition rate 5 Hz, maximum pulse energy 22 mJ) with low duty cycle to reduce a heat accumulation inside the active medium (Yb:glass was only air-cooled). Longitudinally pumped Yb:glass samples were placed inside the 145mm long semi-hemispherical resonator formed by a flat pumping mirror (HR @ 1.0 - 1.1 ?m, HT @ 0.97 ?m) and by curved output coupler (r = 150 mm). Set of output couplers with reflectivity 91 - 97% @ 1.0 - 1.1 ?m was used. Tuning of the Yb:glass laser was accomplished by using a birefringent filter (single 1.5mm thick quartz plate) placed inside the optical resonator at the Brewster angle between the output coupler (reflectivity 97%) and laser active medium. In untuned regime the energy up to 2.4mJ was obtained at wavelength 1050 nm. Slope efficiency up to 17% in respect to absorbed pumping was reached with the 2mm sample. In tuned regime the smooth laser tuning curve, limited by used Lyot filter, extended from 1005nm up to 1080nm (FWHM 48 nm). The maximum output energy of 1.65mJ was obtained at 1060nm for the absorbed energy 16 mJ.

Å ulc, Jan; Krivosudský, Ondrej; Jelínková, Helena; Stepien, Ryszard

2013-03-01

157

Eu 3F 4S 2: Synthesis, crystal structure, and magnetic properties of the mixed-valent europium(II,III) fluoride sulfide EuF 2·(EuFS) 2  

NASA Astrophysics Data System (ADS)

Using the method to synthesize rare-earth metal(III) fluoride sulfides MFS ( M=Y, La, Ce-Lu), in some cases we were able to obtain mixed-valent compounds such as Yb 3F 4S 2 instead. With Eu 3F 4S 2 another isotypic representative has now been synthesized. Eu 3F 4S 2 (tetragonal, I4 /mmm, a=400.34(2), c=1928.17(9) pm, Z=2) is obtained from the reaction of metallic europium, elemental sulfur, and europium trifluoride in a molar ratio of 5:6:4 within seven days at 850 °C in silica-jacketed gas-tightly sealed platinum ampoules. The single-phase product consists of black plate-shaped single crystals with a square cross section, which can be obtained from a flux using equimolar amounts of NaCl as fluxing agent. The crystal structure is best described as an intergrowth structure, in which one layer of CaF 2-type EuF 2 is followed by two layers of PbFCl-type EuFS when sheeted parallel to the (001) plane. Accordingly there are two chemically and crystallographically different europium cations present. One of them (Eu 2+) is coordinated by eight fluoride anions in a cubic fashion, the other one (Eu 3+) exhibits a monocapped square antiprismatic coordination sphere with four F - and five S 2- anions. Although the structural ordering of the different charged europium cations is plausible, a certain amount of charge delocalization with some polaron activity has to take place, which is suggested by the black color of the title compound. Temperature dependent magnetic susceptibility measurements of Eu 3F 4S 2 show Curie-Weiss behavior with an experimental magnetic moment of 8.19(5) ? B per formula unit and a paramagnetic Curie temperature of 0.3(2) K. No magnetic ordering is observed down to 4.2 K. In accordance with an ionic formula splitting like (Eu II)(Eu III) 2F 4S 2 only one third of the europium centers in Eu 3F 4S 2 carry permanent magnetic moments. 151Eu-Mössbauer spectroscopic experiments at 4.2 K show one signal at an isomer shift of -12.4(1) mm/s and a second one at 0.42(4) mm/s. These signals occur in a ratio of 1:2 and correspond to Eu 2+ and Eu 3+, respectively. The spectra at 78 and 298 K are similar, thus no change in the Eu 2+/Eu 3+ fraction can be detected.

Grossholz, Hagen; Hartenbach, Ingo; Kotzyba, Gunter; Pöttgen, Rainer; Trill, Henning; Mosel, Bernd D.; Schleid, Thomas

2009-11-01

158

Stellar neutron capture cross sections of the Yb isotopes  

NASA Astrophysics Data System (ADS)

The neutron capture cross sections of 170Yb, 171Yb, 172Yb, 173Yb, 174Yb, and 176Yb have been measured in the energy range from 3 to 225 keV relative to the gold standard. Neutrons were produced at the Karlsruhe 3.75 MV Van de Graaff Accelerator via the 7Li(p,n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam, and capture events were registered with the Karlsruhe 4? Barium Fluoride Detector. Neutron capture in the even ytterbium isotopes is characterized by a strong population of isomeric states, leading to unrecognized systematic uncertainties in previous measurements. For the first time, partial cross sections to ground and isomeric states could be experimentally identified in neutron time-of-flight measurements for 172Yb, 173Yb, 174Yb, and 176Yb. The present overall uncertainties of (1-1.5) % correspond to an improvement by factors of 4-10 compared to existing data. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT=8 keV and 100 keV. In four cases, the results differ by more than 15% from recent evaluations. The s-process analyses based on the present data provide further evidence in favor of stellar models for thermally pulsing low-mass asymptotic giant branch stars.

Wisshak, K.; Voss, F.; Arlandini, C.; Käppeler, F.; Kazakov, L.

2000-06-01

159

Rare earth-copper-magnesium compounds RECu{sub 9}Mg{sub 2} (RE=Y, La-Nd, Sm-Ho, Yb) with ordered CeNi{sub 3}-type structure  

SciTech Connect

A series of ternary compounds RECu{sub 9}Mg{sub 2} (RE=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb) have been synthesized via induction melting of elemental metal ingots followed by annealing at 400 deg. C for 4 weeks. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDXS) was used for examining microstructure and phase composition. These phases crystallize with an ordered version of the binary hexagonal structure type first reported for CeNi{sub 3}. The crystal structure was solved for TbCu{sub 9}Mg{sub 2} from single crystal X-ray counter data (TbCu{sub 9}Mg{sub 2}-structure type, P6{sub 3} /mmc-space group, hP24-Pearson symbol, a=0.49886 (7) nm, c=1.61646 (3) nm, R {sub F}=0.0474 for 190 unique reflections). The Rietveld refinement of the X-ray powder diffraction patterns of RECu{sub 9}Mg{sub 2} confirmed the same crystal structure for the reported rare earth metals. The unit cell volumes for RECu{sub 9}Mg{sub 2} smoothly follow the lanthanide contraction. The existence of a RECu{sub 9}Mg{sub 2} phase was excluded for RE=Er Tm under the investigated experimental conditions. - Graphical abstract: The perspective view of the arrangement of the icosahedrons and anti-cubooctahedrons in the structure of TbCu{sub 9}Mg{sub 2}.

Solokha, P. [Department of Inorganic Chemistry, Ivan Franko National University of Lviv, Kyryl and Mefodiy str. 6, 79005 Lviv (Ukraine)]. E-mail: solokha_pavlo@yahoo.com; Pavlyuk, V. [Department of Inorganic Chemistry, Ivan Franko National University of Lviv, Kyryl and Mefodiy str. 6, 79005 Lviv (Ukraine); Jan Dlugosz University of Czestochowa, Institute of Chemistry and Environmental Protection, al. Armii Krajowej 13/15, 42200, Czestochowa (Poland); Saccone, A. [Dipartimento di Chimica e Chimica Industriale, Sezione di Chimica Inorganica e Metallurgia, Universita di Genova, Via Dodecaneso 31, I-16146 Genova (Italy); De Negri, S. [Dipartimento di Chimica e Chimica Industriale, Sezione di Chimica Inorganica e Metallurgia, Universita di Genova, Via Dodecaneso 31, I-16146 Genova (Italy); Prochwicz, W. [Jan Dlugosz University of Czestochowa, Institute of Chemistry and Environmental Protection, al. Armii Krajowej 13/15, 42200, Czestochowa (Poland); Marciniak, B. [Jan Dlugosz University of Czestochowa, Institute of Chemistry and Environmental Protection, al. Armii Krajowej 13/15, 42200, Czestochowa (Poland); Rozycka-Sokolowska, E. [Jan Dlugosz University of Czestochowa, Institute of Chemistry and Environmental Protection, al. Armii Krajowej 13/15, 42200, Czestochowa (Poland)

2006-10-15

160

Theoretical analysis of characteristics for 2 ?m Tm3+:Ho3+ co-doped silica fiber laser pumped by a 1550 nm fiber laser  

NASA Astrophysics Data System (ADS)

We established a theoretical model of 2 ?m Tm3+:Ho3+ co-doped silica fiber laser pumped by a 1550 nm fiber laser based on the rate-equation theory and performed the numerical simulation using Runge-Kutta algorithm and Newton-Raphson algorithm. The intracavity power distributions of both pump and laser of the Tm3+:Ho3+ co-doped silica fiber laser based on the Tm3+:Ho3+ co-doped silica fiber supplied by the National Optics Institute in Canada (NOIC) were obtained. The effects of the output reflectivity R4(?s) at the output laser wavelength ?s and the concentrations of Tm3+ and Ho3+ in the fiber on laser output performance were analyzed. In order to achieve a high laser output power, the optimal R4(?s) of 0.13 was verified and the optimal Tm:Ho ratio of 1:2.4 was proposed. Finally, better output performance for the fiber laser based on the optimized Tm3+:Ho3+ co-doped silica fiber was obtained than the laser using the fiber supplied by the NOIC. This theoretical model and numerical simulation results will guide the fabrication of 2 ?m Tm3+:Ho3+ co-doped all-fiber lasers pumped by 1600-nm-band (1500-1750 nm) Er3+:Yb3+ co-doped silica fiber lasers.

Feng, Ting; Yan, Fengping; Peng, Wanjing; Li, Qi; Tan, Siyu; Wang, Jing; Wen, Xiaodong

2012-07-01

161

The spectroscopic properties of Yb3+ doped ?-BBO crystal  

NASA Astrophysics Data System (ADS)

2.0 mol% (relative to Ba2+) Yb3+ doped ?-BaB2O4 (?-BBO) crystal was obtained by the Czochralski method. The doped crystal structure was determined by means of an X-ray diffraction analysis. The absorption, near-infrared (NIR) luminescence spectra and fluorescence decay curve of Yb3+ doped ?-BBO crystal were investigated. NIR emission under 940 nm and 980 nm LDs (laser diodes) excitation was observed in the Yb doped ?-BBO crystal.

Yu, Pingsheng; Su, Liangbi; Wu, Feng; Xu, Jun

2012-05-01

162

The HALO networkTM  

Microsoft Academic Search

The High Altitude Long Operation NetworkTM is a broadband wireless metropolitan area network, with a star topology, whose solitary hub is located in the atmosphere above the service area at an altitude higher than commercial airline traffic. The HALO\\/Proteus airplane is the central node of this network. It will fly at altitudes higher than 51,000 ft. The signal footprint of

M. J. Colella; J. N. Martin; F. Akyildiz

2000-01-01

163

Stellar neutron capture cross sections of the Yb isotopes.  

NASA Astrophysics Data System (ADS)

The neutron capture cross sections of 170Yb, 171Yb, 172Yb, 173Yb, 174Yb, and 176Yb have been measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the 7Li(p,n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4? barium fluoride detector. The cross sections were determined relative to the gold standard. Neutron capture in the even ytterbium isotopes is characterized by a strong population of isomeric states, resulting in severe systematic uncertainties in previous experiments. In the present work, the partial cross sections to the ground- and isomeric states in 172Yb, 174Yb, 176Yb could be experimentally separated for the first time, yielding cross section ratios with an overall uncertainty of 1 - 1.5%. Compared to previous measurements, this corresponds to an improvement by factors of 4 to 10. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT = 8 keV and 100 keV. The results of four isotopes differ by more than 15% from recent evaluations.

Wisshak, K.; Voss, F.; Käppeler, F.; Kazakov, L.

1998-11-01

164

LiquichekTM Tumor Marker Control  

E-print Network

LiquichekTM Tumor Marker Control Bio-Rad Laboratories T U M O R M A R K E R C O N T R O L S #12;T U M O R M A R K E R C O N T R O L S LiquichekTM Tumor Marker Control LiquichekTM Tumor Marker Control is a liquid, human serum based, third party control for monitoring the precision of tumor marker testing

Rodriguez, Carlos

165

Model results of Er-Yb double clad fiber amplifier  

Microsoft Academic Search

We present model calculations of gain at 1550 nm for Er-Yb double clad amplifiers as a function of pump power, pump wavelength, signal input power, and fiber length. The absorption coefficient of Yb varies ( by a factor of ~ 5) with the pump wavelength in the range of 910 to 990 nm. However, semiconductor lasers may be available only

Z. Chen; H. Sun; S. Ma; N. K. Dutta

2007-01-01

166

New LED In Synthesized InP : Yb Material  

NASA Astrophysics Data System (ADS)

New light emitting diodes at 1.00 ?m obtained from synthesized InP : Yb bulk crystal are studied. The n-type Yb doped bulk material was grown by gradient freeze method. Mg+ ions were implanted in this material for p-type layer. The indepth localization of the junction is not critical. Photoluminescence and electroluminescence spectra are performed from 77 K to 300 K. Two peaks are observed : band edge emission (0.88 pm) and intra shell 4f-4f for Yb ions. The variation of EL intensity with diode forward current shows a Yb3+ emission about 40 times higher than band edge emission. No influence of temperature is observed on Yb3+ peak linewidth and wavelength.

L'Haridon, H.; Moutonnet, D.; Toudic, Y.; Salvi, M.; Favennec, P. N.

1989-11-01

167

Abnormal size-dependent upconversion emissions and multi-color tuning in Er3+-doped CaF2-YbF3 disordered solid-solution nanocrystals  

NASA Astrophysics Data System (ADS)

A series of Er3+-doped (1 - x)CaF2-xYbF3 (0 ? x ? 0.6) disordered solid-solution nanocrystals with various mean sizes were successfully prepared by a facile solvothermal route. Interestingly, abnormal size-dependent upconversion emissions were demonstrated in these nanocrystals for the first time. With increasing grain size, an obvious enhancement of red to green emission ratio was observed in the Er3+ (2 mol%): 0.4CaF2-0.6YbF3 nanocrystals, which is the opposite of the routine size-dependent upconversion emission behavior reported previously. Taking Eu3+ ions as a structural probe, we investigated the influence of a disordered solid-solution structure on Ln3+ luminescence, and proposed that Ln3+ clusters formed in the host should play a key role to induce this unusual size-dependent upconversion emission phenomenon. As a consequence, multi-colors such as green, yellow, and red upconversion emissions can be easily realized by appropriately modifying the Yb3+ content in the Er3+-doped (1 - x)CaF2-xYbF3 nanocrystals. The reported results will deepen the understanding of size effects on the lanthanide upconversion in nanocrystals.

Chen, Daqin; Lei, Lei; Xu, Ju; Yang, Anping; Wang, Yuansheng

2013-03-01

168

JOURSAL OF MOLECULARSPECTROSCOPY64, 233-243 (1977) Chemiluminescent Spectra of YbF and YbCl  

E-print Network

molecular states arising from the separated atoms Yb(5d) + X(np) as well as Yb(6p) + X(np) is be- lieved transitions of a considerable number of the lanthanide mono- halides have been observed in absorption (I-3

Zare, Richard N.

169

Nanosecond cryogenic Yb:YAG disk laser  

NASA Astrophysics Data System (ADS)

A cryogenic Yb:YAG disk laser is modernised to increase its average and peak power. The master oscillator unit of the laser is considerably modified so that the pulse duration decreases to several nanoseconds with the same pulse energy. A cryogenic disk laser head with a flow-through cooling system is developed. Based on two such laser heads, a new main amplifier is assembled according to an active multipass cell scheme. The total small-signal gain of cryogenic cascades is ~108.

Perevezentsev, E. A.; Mukhin, I. B.; Kuznetsov, I. I.; Vadimova, O. L.; Palashov, O. V.

2014-05-01

170

Anisotropic magnetization and transport properties of RAgSb{sub 2} (R=Y, La-Nd, Sm, Gd-Tm)  

SciTech Connect

This study of the RAgSb{sub 2} series of compounds arose as part of an investigation of rare earth intermetallic compounds containing antimony with the rare earth in a position with tetragonal point symmetry. Materials with the rare earth in a position with tetragonal point symmetry frequently manifest strong anisotropies and rich complexity in the magnetic properties, and yet are simple enough to analyze. Antimony containing intermetallic compounds commonly possess low carrier densities and have only recently been the subject of study. Large single grain crystals were grown of the RAgSb{sub 2} (R=Y, La-Nd, Sm, Gd-Tm) series of compounds out of a high temperature solution. This method of crystal growth, commonly known as flux growth is a versatile method which takes advantage of the decreasing solubility of the target compound with decreasing temperature. Overall, the results of the crystal growth were impressive with the synthesis of single crystals of LaAgSb{sub 2} approaching one gram. However, the sample yield diminishes as the rare earth elements become smaller and heavier. Consequently, no crystals could be grown with R=Yb or Lu. Furthermore, EuAgSb{sub 2} could not be synthesized, likely due to the divalency of the Eu ion. For most of the RAgSb{sub 2} compounds, strong magnetic anisotropies are created by the crystal electric field splitting of the Hund's rule ground state. This splitting confines the local moments to lie in the basal plane (easy plane) for the majority of the members of the series. Exceptions to this include ErAgSb{sub 2} and TmAgSb{sub 2}, which have moments along the c-axis (easy axis) and CeAgSb{sub 2}, which at intermediate temperatures has an easy plane, but exchange coupling at low temperatures is anisotropic with an easy axis. Additional anisotropy is also observed within the basal plane of DyAgSb{sub 2}, where the moments are restricted to align along one of the {l_angle}110{r_angle} axes. Most of the RAgSb{sub 2} compounds containing magnetic rare earths, antiferromagnetically ordered at low temperatures. The ordering temperatures of these compounds are approximately proportional to the de Gennes factor, which suggests that the RKKY interaction is the dominant exchange interaction between local moments. Although metamagnetic transitions were observed in many members of the series, the series of sharp step-like transitions in DyAgSb{sub 2} are impressive. In this compound, up to 11 different magnetic states are stable depending on the magnitude and direction of the applied field. The saturated magnetization of these states and the critical fields needed to induce a phase transition vary with the direction of the applied field. Through detailed study of the angular dependence of the magnetization and critical fields, the net distribution of magnetic moments was determined for most, of the metamagnetic states. In DyAgSb{sub 2}, the crystal electric field (CEF) splitting of the Hund's rule ground state creates a strong anisotropy where the local Dy{sup 3+} magnetic moments are constrained to one of the equivalent {l_angle}110{r_angle} directions within the basal plane. The four position clock model was introduced to account for this rich metamagnetic system. Within this model, the magnetic moments are constrained to one of four equivalent orientations within the basal plane and interactions are calculated for up third nearest neighbors. The theoretical phase diagram, generated from the coupling constants is in excellent agreement with the experimental phase diagram. Further investigation of this compound using magnetic X-ray or neutron diffraction would be extremely useful to verify the net distributions of moments and determine the wave vectors of each of the ordered states.

Myers, Kenneth D.

1999-11-08

171

Immunocytochemical study of YB-1 nuclear distribution in different cell types.  

PubMed

In the present work we studied the distribution of YB-1 in the nuclei of mouse hepatocytes, early embryos and human skin fibroblasts with the use of light and electron microscopy. To reveal YB-1, we applied rat polyclonal antibody against the C-terminal fragment of YB-1 molecule and rabbit polyclonal antibody against full-length YB-1 molecule. YB-1 distribution patterns varied significantly in different cell types. YB-1 was found to be colocalized with RNA polymerase I in mouse hepatocytes and embryos. Besides, YB-1 was revealed in a population of Cajal bodies in 2-cell mouse embryos but not in other cells studied. PMID:25175035

Bogolyubova, I O; Lyabin, D N; Bogolyubov, D S; Ovchinnikov, L P

2014-12-01

172

A Review of "Integrity[TM]"  

ERIC Educational Resources Information Center

Integrity[TM], an online application for testing both the statistical integrity of the test and the academic integrity of the examinees, was evaluated for this review. Program features and the program output are described. An overview of the statistics in Integrity[TM] is provided, and the application is illustrated with a small simulation study.…

Veldkamp, Bernard P.

2008-01-01

173

From stable divalent to valence-fluctuating behaviour in Eu(Rh(1-x)Ir(x))2Si2 single crystals.  

PubMed

We have succeeded in growing high-quality single crystals of the valence-fluctuating system EuIr(2)Si(2), the divalent Eu system EuRh(2)Si(2) and the substitutional alloy Eu(Rh(1-x)Ir(x))(2)Si(2) across the range 0 < x < 1, which we characterized by means of x-ray diffraction, energy-dispersive x-ray spectroscopy, specific heat, magnetization and resistivity measurements. On increasing x, the divalent Eu ground state subsists up to x = 0.25 with a slight increase in Néel temperature, while for 0.3?x < 0.7 a sharp hysteretic change in susceptibility and resistivity marks the first-order valence transition. For x?0.7 the broad feature observed in the physical properties is characteristic of the continuous valence evolution beyond the critical end point of the valence transition line, and the resistivity is reminiscent of Kondo-like behaviour while the Sommerfeld coefficient indicates a mass renormalization of at least a factor of 8. The resulting phase diagram is similar to those reported for polycrystalline Eu(Pd(1-x)Au(x))(2)Si(2) and EuNi(2)(Si(1-x)Ge(x))(2), confirming its generic character for Eu systems, and markedly different to those of homologue Ce and Yb systems, which present a continuous suppression of the antiferromagnetism accompanied by a very smooth evolution of the valence. We discuss these differences and suggest them to be related to the large polarization energy of the Eu half-filled 4f shell. We further argue that the changes in the rare earth valence between RRh(2)Si(2) and RIr(2)Si(2) (R = Ce, Eu, Yb) are governed by a purely electronic effect and not by a volume effect. PMID:21878716

Seiro, Silvia; Geibel, Christoph

2011-09-21

174

1 Problem The Levitron TM  

E-print Network

A science toy marketed under the name Levitron TM [1] consists of a bar magnet of mass m and magnetic dipole moment ? that is levitated above a static magnetic field which is circularly symmetric about the vertical (z) axis (such as that of a loop of current perpendicular to the z-axis). The magnet is also spinning with angular velocity ? about its symmetry axis, which axis is parallel to ?. Deduce conditions on the derivatives of the magnetic field such that the center of mass motion of the magnet is stable. You may assume that ? is large enough that the rotational motion is stable, and that the equilibrium point lies on the symmetry axis of the magnetic field. For the example of a magnet levitated antiparallel to the field of a loop of radius a that carries a steady current, find the range of equilibrium heights z0 above the plane of the loop for which the motion is stable. 2

Kirk T. Mcdonald

175

Scintillation properties of Yb3+-doped YAG transparent ceramics  

NASA Astrophysics Data System (ADS)

We investigated scintillation properties of Yb3+-doped Y3A5O12 (YAG) transparent ceramics with different dopant concentrations. The transparency of both 0.3% and 15% Yb3+-doped exceeded 70% in the wavelength range 300-800 nm, and two kinds of absorption bands due to charge transfer (CT) transition and 4f-4f forbidden transition of Yb3+ were observed around 200-250 nm and 900 nm, respectively. Ultraviolet luminescence caused by the CT transition between Yb3+ and O2- was observed under ?-ray excitation from 241Am sealed source. The scintillation decay times were determined to be about 2.2 ns (Yb 0.3%) and 1.4 ns (Yb 15%) using the streak camera system equipped with pulsed X-ray source. From 241Am alpha-ray-excited pulse height spectra, the relative scintillation light yield of 0.3% and 15% Yb3+-doped ceramics was 7% and 10% compared with that of BGO commercial scintillator.

Fujimoto, Yutaka; Yanagida, Takayuki; Wakahara, Shingo; Yagi, Hideki; Yanagidani, Takagimi; Kurosawa, Shunsuke; Yoshikawa, Akira

2013-02-01

176

Monodisperse core-shell structured up-conversion Yb(OH)CO?@YbPO?:Er³+ hollow spheres as drug carriers.  

PubMed

In this work, we report a facile solution-phase synthesis of monodisperse core-shell structured Yb(OH)CO?@YbPO? hollow spheres (size around 380 nm) by utilizing the colloidal sphere of Yb(OH)CO? as the sacrificial template via the Kirkendall effect. The Er³+ doped Yb(OH)CO?@YbPO? core-shell hollow spheres can be prepared similarly, which exhibit strong green emission under 980 nm NIR laser excitation even after loading with drug molecules. Most importantly, the sample can be used as an effective drug delivery carrier. The biocompatibility test on L929 fibroblast cells using MTT assay reveals low cytotoxicity of the system. A typical anticancer drug, doxorubicin hydrochloride (DOX), is used for drug loading, and the release properties, cytotoxicity, uptake behavior and therapeutic effects were examined. It is found that DOX is shuttled into cell by core-shell hollow spheres carrier and released inside cells after endocytosis, and the DOX-loaded spheres exhibited greater cytotoxicity than free DOX. These results indicate that the core-shell Er³+ doped Yb(OH)CO?@YbPO? hollow spheres have potential for drug loading and delivery into cancer cells to induce cell death. PMID:21435712

Xu, Zhenhe; Ma, Ping'an; Li, Chunxia; Hou, Zhiyao; Zhai, Xuefeng; Huang, Shanshan; Lin, Jun

2011-06-01

177

Ternary rare earth-lanthanide sulfides. [Re = Eu, Sm or Yb  

DOEpatents

Disclosed is a new ternary rare earth sulfur compound having the formula La/sub 3-x/M/sub x/S/sub 4/, where M is europium, samarium, or ytterbium, with x = 0.15 to 0.8. The compound has good high-temperature thermoelectric properties and exhibits long-term structural stability up to 1000/sup 0/C.

Takeshita, Takuo; Gschneidner, K.A. Jr.; Beaudry, B.J.

1986-03-06

178

Preliminary Evaluation of TM for Soils Information  

NASA Technical Reports Server (NTRS)

The capability of the LANDSAT TM for providing information for soil association maps and for detecting soil properties (variability within vegetated fields) was assessed using TM imagery of fields in Mississippi County, Arkansas that were planted with rice, cotton, and soybeans. Results indicate that the TM bands are providing information that is related to the soil properties within the field. Over large areas, these bands also appear to provide information that is related to the soil properties that are important to plant condition. While these results are only an indication of the information that TM can provide, they do indicate the TM data--especially, the mid-TR and thermal bands--show the capability for separating vegetated soil landscapes on a broad basis. The analysis at the field level with a growing crop also indicates that TM, with its additional and narrower bands and improved spatial and radiometric resolution is influenced by within field variability due to soils that has to be accounted for in the analysis of TM data.

Thompson, D. R.; Henderson, K. E.; Houston, A. G.; Pitts, D. E.

1985-01-01

179

Infrared spectroscopy of the intermediate-valence semiconductor YbB{sub 12}  

SciTech Connect

The dynamic conductivity and permittivity spectra of the intermediate-valence compound YbB{sub 12} are measured in the frequency range (6-10{sup 4}) cm{sup -1} (quantum energy 0.75 meV-1.24 eV) at temperatures of 5-300 K. Analysis of the spectral singularities associated with the response of free charge carriers has made it possible for the first time to determine the temperature dependences of their microscopic parameters, viz., concentration, effective mass, relaxation frequency and time, mobility, and plasma frequency. It is shown that the relaxation frequency decreases upon cooling from 300 K to the coherence temperature T* = 70 K for YbB{sub 12}, which is mainly associated with the phonon mechanism of scattering of charge carriers. For cooling below the coherence temperature T* = 70 K, the temperature dependence of the relaxation frequency for charge carriers of the Fermi-liquid type is found to be {gamma} {approx} {gamma}{sub 0} + T{sup 2}, while their effective mass and relaxation time increase, respectively, to m*(20 K) = 34m{sub 0} (m{sub 0} is the free electron mass) and {tau}(20 K) = 4 x 10{sup -13} s, indicating the establishment of coherent scattering of carriers from localized magnetic moments of the f centers. At a temperature of T = 5 K, the conductivity spectrum contains an absorption line at a frequency of 22 cm{sup -1} (2.7 meV); the origin of this line can be associated with the exciton-polaron bound state. Since such a state was observed earlier in other intermediate-valence semiconductors (such as SmB{sub 6}, TmSe{sub 1-x}Te, and (Sm, Y)S), it is probably typical of this class of compounds.

Gorshunov, B. P., E-mail: gorshunov@ran.gpi.ru; Prokhorov, A. S.; Spektor, I. E.; Volkov, A. A. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Dressel, M. [Universitaet Stuttgart, Physikalisches Institut (Germany); Iga, F. [Hiroshima University, Graduate School of ADSM (Japan)

2006-12-15

180

Level densities and $?$-ray strength functions in $^{170,171,172}$Yb  

E-print Network

Level densities and radiative strength functions in $^{171}$Yb and $^{170}$Yb nuclei have been measured using the $^{171}$Yb($^3$He,$^3$He$^\\prime\\gamma$)$^{171}$Yb and $^{171}$Yb($^3$He,$\\alpha\\gamma$)$^{170}$Yb reactions. New data on $^{171}$Yb are compared to a previous measurement for $^{171}$Yb from the $^{172}$Yb($^3$He,$\\alpha\\gamma$)$^{171}$Yb reaction. Systematics of level densities and radiative strength functions in $^{170,171,172}$Yb are established. The entropy excess in $^{171}$Yb relative to the even-even nuclei $^{170,172}$Yb due to the unpaired neutron quasiparticle is found to be approximately 2$k_B$. Results for the radiative strength function from the two reactions lead to consistent parameters characterizing the ``pygmy'' resonances. Pygmy resonances in the $^{170,172}$Yb populated by the ($^3$He,$\\alpha$) reaction appear to be split into two components for both of which a complete set of resonance parameters are obtained.

U. Agvaanluvsan; A. Schiller; J. A. Becker; L. A. Bernstein; P. E. Garrett; M. Guttormsen; G. E. Mitchell; J. Rekstad; S. Siem; A. Voinov; W. Younes

2004-12-13

181

Optical properties of Yb 3+-doped phosphate laser glasses  

Microsoft Academic Search

Ytterbium-doped phosphate glasses have been prepared and studied their spectroscopic properties through absorption, emission and Fourier transform infrared (FTIR) spectral studies and time-resolved luminescence decay curves. The absorption cross-section has been found to vary with the variation of Yb2O3 concentration. The results of the FTIR spectra show that the OH? content is increasing with increase of the Yb2O3 concentration in

V. Venkatramu; R. Vijaya; S. F. León-Luis; P. Babu; C. K. Jayasankar; V. Lavín; L. J. Dhareshwar

2011-01-01

182

Phase stability of AlYB14 sputtered thin films  

Microsoft Academic Search

AlYB14 (Imma) thin films were synthesized by magnetron sputtering. On the basis of x-ray diffraction, no phases other than crystalline AlYB14 could be identified. According to electron probe microanalysis, energy dispersive x-ray analysis and elastic recoil detection analysis, the Al and Y occupancies vary in the range of 0.73-1.0 and 0.29-0.45, respectively. Density functional theory based calculations were carried out

Helmut Kölpin; Graeme Henkelman; Jens Emmerlich; Frans Munnik; Jochen M. Schneider

2009-01-01

183

The GEMnet (TM) global data communication  

NASA Technical Reports Server (NTRS)

The GEMnet(TM) (Global Electronics Message network) will provide global digital data communications anywhere in the world at any time for minimum cost. GEMnet(TM) is an end-to-end Non-Voice Non-Geostationary Mobile Satellite (NVNG) (sometimes dubbed 'Little LEO') System which consists of a constellation of 38 low Earth orbiting small satellites and a ground segment. The GEMnet(TM) ground segment will consist of subscriber user terminals, gateway stations, a Network Operational Center(NOC), and a backbone network interconnecting the NOC and gateways. This paper will describe the GEMnet(TM) system concept including ground and space segments, system heritage, data communication services, and protocols.

Yi, Byung K.; Chitty, Richard; Walters, Dave; Howard, Regan

1995-01-01

184

AMD GeodeTM LX Processors Data Book AMD GeodeTM LX Processors  

E-print Network

are not designed, intended, authorized or warranted for use as components in systems intended for surgical implant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.4 GeodeLinkTM Memory Controller

Zhang, Xiaodong

185

Unusual weak magnetic exchange in two different structure types: YbPt2Sn and YbPt2In  

NASA Astrophysics Data System (ADS)

We present the structural, magnetic, thermodynamic and transport properties of the two new compounds YbPt2Sn and YbPt2In. X-ray powder diffraction shows that they crystallize in different structure types, the hexagonal ZrPt2Al and the cubic Heusler type, respectively. Despite quite different lattice types, both compounds present very similar magnetic properties: a stable trivalent Yb3+, no evidence for a sizeable Kondo interaction and very weak exchange interactions with a strength below 1 K as deduced from specific heat C(T). Broad anomalies in C(T) suggest short range magnetic ordering at about 250 mK and 180 mK for YbPt2Sn and YbPt2In, respectively. The weak exchange and the low ordering temperature result in a large magnetocaloric effect as deduced from the magnetic field dependence of C(T), making these compounds interesting candidates for magnetic cooling. In addition we found in YbPt2In evidences for a charge density wave transition at about 290 K. The occurrence of such transitions within several RET2X compound series (RE = rare earth, T = noble metal, X = In, Sn) is analyzed.

Gruner, T.; Jang, D.; Steppke, A.; Brando, M.; Ritter, F.; Krellner, C.; Geibel, C.

2014-12-01

186

Unusual weak magnetic exchange in two different structure types: YbPt2Sn and YbPt2In.  

PubMed

We present the structural, magnetic, thermodynamic and transport properties of the two new compounds YbPt2Sn and YbPt2In. X-ray powder diffraction shows that they crystallize in different structure types, the hexagonal ZrPt2Al and the cubic Heusler type, respectively. Despite quite different lattice types, both compounds present very similar magnetic properties: a stable trivalent Yb(3+), no evidence for a sizeable Kondo interaction and very weak exchange interactions with a strength below 1 K as deduced from specific heat C(T). Broad anomalies in C(T) suggest short range magnetic ordering at about 250 mK and 180 mK for YbPt2Sn and YbPt2In, respectively. The weak exchange and the low ordering temperature result in a large magnetocaloric effect as deduced from the magnetic field dependence of C(T), making these compounds interesting candidates for magnetic cooling. In addition we found in YbPt2In evidences for a charge density wave transition at about 290 K. The occurrence of such transitions within several RET2X compound series (RE = rare earth, T = noble metal, X = In, Sn) is analyzed. PMID:25322667

Gruner, T; Jang, D; Steppke, A; Brando, M; Ritter, F; Krellner, C; Geibel, C

2014-12-01

187

HSP60 interacts with YB-1 and affects its polysome association and subcellular localization  

SciTech Connect

YB-1 is a DNA/RNA-binding protein which, in the cytoplasm, associates with polysomes and regulates translation. However, YB-1 has a novel nuclear localization signal, and its nuclear accumulation is correlated with cancer induction. Here we designated the amino-acid sequence as YB-NLS and demonstrated that YB-NLS is necessary for the nuclear translocation of overexpressed YB-1 in NG108-15 cells. In addition, we found that a heat shock protein, HSP60, binds to YB-NLS in the cytoplasm. Interestingly, when HSP60 expression was repressed, an increase of polysome-associated YB-1 was observed in heavy-sedimenting fractions on a sucrose gradient. Overexpression of HSP60 resulted in a decrease of YB-1 in the heavy-sedimenting fractions and suppression of YB-NLS activity. Furthermore, the NLS-deleted YB-1 was apparently associated with the heavy-sedimenting polysomes. These results suggest that HSP60 interacts with YB-1 at the YB-NLS region and acts as a regulator of polysome association and the subcellular distribution of YB-1.

Ohashi, Sachiyo; Atsumi, Megumi [Research Unit of Biochemistry, College of Pharmacy, Nihon University, Narashinodai, Funabashi, Chiba 274-8555 (Japan)] [Research Unit of Biochemistry, College of Pharmacy, Nihon University, Narashinodai, Funabashi, Chiba 274-8555 (Japan); Kobayashi, Shunsuke, E-mail: kobayashi.shunsuke@nihon-u.ac.jp [Research Unit of Biochemistry, College of Pharmacy, Nihon University, Narashinodai, Funabashi, Chiba 274-8555 (Japan)] [Research Unit of Biochemistry, College of Pharmacy, Nihon University, Narashinodai, Funabashi, Chiba 274-8555 (Japan)

2009-08-07

188

Modeling Cr-to-Tm and Cr-to-Tm-to-Ho energy transfer in YAG crystals  

NASA Technical Reports Server (NTRS)

A systematic analysis of energy transfer processes in crystals of YAG doped with varying concentrations of Cr and Tm is described. Both spectral measurements and measurements of the temporal response to pulsed excitation are used to give independent determinations of the microscopic interaction parameter for Cr to Tm transfer. The different factors in influencing the temperature dependence of the Cr to Tm transfer are discussed. The dependence of the Tm cross-relaxation rate on Tm concentration is determined.

Swetits, John J.

1991-01-01

189

TM-align: a protein structure alignment algorithm based on the TM-score  

Microsoft Academic Search

We have developed TM-align, a new algorithm to identify the best structural alignment between protein pairs that combines the TM-score rotation matrix and Dynamic Programming (DP). The algo- rithm is ? 4 times faster than CE and 20 times faster than DALI and SAL. On average, the resulting struc- ture alignments have higher accuracy and coverage than those provided by

Yang Zhang; Jeffrey Skolnick

2005-01-01

190

Concurrent Validity of LibQUAL+[TM] Scores: What Do LibQUAL+[TM] Scores Measure?  

ERIC Educational Resources Information Center

The present study investigated the validity of LibQUAL+[TM] scores, and specifically how total and subscale LibQUAL+[TM] scores are associated with self-reported, library-related satisfaction and outcomes scores. Participants included 88,664 students and faculty who completed the American English (n[AE] = 69,494) or the British English (n[BE] =…

Thompson, Bruce; Cook, Colleen; Kyrillidou, Martha

2005-01-01

191

COMPOSITE TECHNOLOGY DEVELOPMENT INC. CryoCoatTM UltraLightTM  

E-print Network

: Adhesives Thermal Insulation Protective Coatings Each layer can be optimized gives best system performance Change to LHe Stop LHe Flow Insulation Thickness Approx. 1 1/2" LN2 Pre-Cool Thermal Time HistoryCOMPOSITE TECHNOLOGY DEVELOPMENT INC. CTD CryoCoatTM UltraLightTM Insulation presented by: Michael

McDonald, Kirk

192

In vitro and in vivo characterization of four fibroblast tropomyosins produced in bacteria: TM-2, TM-3, TM-5a, and TM-5b are co-localized in interphase fibroblasts.  

PubMed

Most cell types express several tropomyosin isoforms, the individual functions of which are poorly understood. In rat fibroblasts there are at least six isoforms; TM-1, TM-2, TM-3, TM-4, TM-5a, and TM-5b. TM-1 is the product of the beta gene. TM-4 is produced from the TM-4 gene, and TMs 2, 3, 5a, and 5b are the products of the alpha gene. To begin to study the localization and function of the isoforms in fibroblasts, cDNAs for TM isoforms 2, 3, 5a, and 5b were placed into bacterial expression vectors and used to produce TM isoforms. The bacterially produced TMs were determined to be full length by sequencing the amino- and carboxy termini. These TMs were found to bind to F-actin in vitro, with properties similar to that of skeletal muscle TM. In addition, competition experiments demonstrated that TM-5b was better than TM-5a in displacing other TM isoforms from F-actin in vitro. To investigate the intracellular localization of these fibroblast isoforms, each was derivatized with a fluorescent chromophore and microinjected into rat fibroblasts. TM-2, TM-3, TM-5a, and TM-5b were each found to associate along actin filaments. There was no preferred cellular location or subset of actin filaments for these isoforms. Furthermore, co-injection of two isoforms labeled with different fluorochromes showed identical staining. At the level of the light microscope, these isoforms from the alpha gene do not appear to achieve different functions by binding to particular subsets of actin filaments or locations in cells. Some alternative possibilities are discussed. The results show that bacterially produced TMs can be used to study in vitro and in vivo properties of the isoforms. PMID:1500427

Pittenger, M F; Helfman, D M

1992-08-01

193

Physical properties of superbulky lanthanide metallocenes: synthesis and extraordinary luminescence of [Eu(II)(Cp(BIG))2] (Cp(BIG) = (4-nBu-C6H4)5-cyclopentadienyl).  

PubMed

The superbulky deca-aryleuropocene [Eu(Cp(BIG))2], Cp(BIG) = (4-nBu-C6H4)5-cyclopentadienyl, was prepared by reaction of [Eu(dmat)2(thf)2], DMAT = 2-Me2N-?-Me3Si-benzyl, with two equivalents of Cp(BIG)H. Recrystallizyation from cold hexane gave the product with a surprisingly bright and efficient orange emission (45% quantum yield). The crystal structure is isomorphic to those of [M(Cp(BIG))2] (M = Sm, Yb, Ca, Ba) and shows the typical distortions that arise from Cp(BIG)???Cp(BIG) attraction as well as excessively large displacement parameter for the heavy Eu atom (U(eq) = 0.075). In order to gain information on the true oxidation state of the central metal in superbulky metallocenes [M(Cp(BIG))2] (M = Sm, Eu, Yb), several physical analyses have been applied. Temperature-dependent magnetic susceptibility data of [Yb(Cp(BIG))2] show diamagnetism, indicating stable divalent ytterbium. Temperature-dependent (151)Eu Mössbauer effect spectroscopic examination of [Eu(Cp(BIG))2] was examined over the temperature range 93-215?K and the hyperfine and dynamical properties of the Eu(II) species are discussed in detail. The mean square amplitude of vibration of the Eu atom as a function of temperature was determined and compared to the value extracted from the single-crystal X-ray data at 203?K. The large difference in these two values was ascribed to the presence of static disorder and/or the presence of low-frequency torsional and librational modes in [Eu(Cp(BIG))2]. X-ray absorbance near edge spectroscopy (XANES) showed that all three [Ln(Cp(BIG))2] (Ln = Sm, Eu, Yb) compounds are divalent. The XANES white-line spectra are at 8.3, 7.3, and 7.8?eV, for Sm, Eu, and Yb, respectively, lower than the Ln2O3 standards. No XANES temperature dependence was found from room temperature to 100?K. XANES also showed that the [Ln(Cp(BIG))2] complexes had less trivalent impurity than a [EuI2(thf)x] standard. The complex [Eu(Cp(BIG))2] shows already at room temperature strong orange photoluminescence (quantum yield: 45?%): excitation at 412?nm (24,270?cm(-1)) gives a symmetrical single band in the emission spectrum at 606?nm (?max =16495?cm(-1), FWHM: 2090?cm(-1), Stokes-shift: 2140?cm(-1)), which is assigned to a 4f(6)5d(1) ? 4f(7) transition of Eu(II). These remarkable values compare well to those for Eu(II)-doped ionic host lattices and are likely caused by the rigidity of the [Eu(Cp(BIG))2] complex. Sharp emission signals, typical for Eu(III), are not visible. PMID:23907896

Harder, Sjoerd; Naglav, Dominik; Ruspic, Christian; Wickleder, Claudia; Adlung, Matthias; Hermes, Wilfried; Eul, Matthias; Pöttgen, Rainer; Rego, Daniel B; Poineau, Frederic; Czerwinski, Kenneth R; Herber, Rolfe H; Nowik, Israel

2013-09-01

194

The tmRDB and SRPDB resources  

PubMed Central

Maintained at the University of Texas Health Science Center at Tyler, Texas, the tmRNA database (tmRDB) is accessible at the URL with mirror sites located at Auburn University, Auburn, Alabama () and the Royal Veterinary and Agricultural University, Denmark (). The signal recognition particle database (SRPDB) at is mirrored at and the University of Goteborg (). The databases assist in investigations of the tmRNP (a ribonucleoprotein complex which liberates stalled bacterial ribosomes) and the SRP (a particle which recognizes signal sequences and directs secretory proteins to cell membranes). The curated tmRNA and SRP RNA alignments consider base pairs supported by comparative sequence analysis. Also shown are alignments of the tmRNA-associated proteins SmpB, ribosomal protein S1, alanyl-tRNA synthetase and Elongation Factor Tu, as well as the SRP proteins SRP9, SRP14, SRP19, SRP21, SRP54 (Ffh), SRP68, SRP72, cpSRP43, Flhf, SRP receptor (alpha) and SRP receptor (beta). All alignments can be easily examined using a new exploratory browser. The databases provide links to high-resolution structures and serve as depositories for structures obtained by molecular modeling. PMID:16381838

Andersen, Ebbe Sloth; Rosenblad, Magnus Alm; Larsen, Niels; Westergaard, Jesper Cairo; Burks, Jody; Wower, Iwona K.; Wower, Jacek; Gorodkin, Jan; Samuelsson, Tore; Zwieb, Christian

2006-01-01

195

Photodarkening in Yb-doped aluminosilicate fibers induced by 488 nm irradiation  

Microsoft Academic Search

Photodarkening of Yb-doped aluminosilicate fibers by continuous wave 488nm irradiation was investigated. The irradiation induced significant excess loss in the UV-visible spectroscopy (VIS) region in Yb-doped aluminosilicate fibers while pure aluminosilicate fibers showed negligible induced loss. Ultraviolet-VIS-near-infrared spectroscopy revealed an absorption peak at 220nm in unexposed Yb-doped aluminosilicate fiber preforms. The observed peak was attributed to Yb-associated oxygen deficiency centers

S. Yoo; C. Basu; A. J. Boyland; C. Sones; J. Nilsson; J. K. Sahu; D. Payne

2007-01-01

196

Yb3+/Ho3+-codoped antimony-silicate optical fiber  

NASA Astrophysics Data System (ADS)

The emission properties of Yb3+/Ho3+-codoped antimony-silicate optical fiber has been investigated. Luminescence at 2.1 ?m corresponding to 5I7--> 5I8 transition in holmium was obtained by energy transfer between Yb3+ and Ho3+ ions. According to the Dexter-Miyakawa model, the parameters of energy migration CDD of the 2F5/2 (Yb3+) <--> 2F5/2 (Yb3+) transition and direct energy transfer CDA of the 2F5/2 (Yb3+) --> 5I6 (Ho3+) transition was calculated. The optimization of the activator content and the concentration ratio were conducted with the purpose of maximizing the efficiency of energy transfer. It made possible to select best-suited glass which was used to manufacture double-clad optical fiber. Strong and narrow bands of spontaneous emission which formed as a result of energy transfer between ytterbium and holmium ions were observed in the fiber under exciting with radiation at 978 nm wavelength.

?mojda, Jacek; Dorosz, Dominik; Kochanowicz, Marcin; Miluski, Piotr; Dorosz, Jan

2012-05-01

197

High-pressure synthesis, crystal structure, and structural relationship of the first ytterbium fluoride borate Yb{sub 5}(BO{sub 3}){sub 2}F{sub 9}  

SciTech Connect

Yb{sub 5}(BO{sub 3}){sub 2}F{sub 9} was synthesized under high-pressure/high-temperature conditions in a Walker-type multianvil apparatus at 7.5 GPa and 1100 deg. C, representing the first known ytterbium fluoride borate. The compound exhibits isolated BO{sub 3}-groups next to ytterbium cations and fluoride anions, showing a structure closely related to the other known rare-earth fluoride borates RE{sub 3}(BO{sub 3}){sub 2}F{sub 3} (RE=Sm, Eu, Gd) and Gd{sub 2}(BO{sub 3})F{sub 3}. Monoclinic Yb{sub 5}(BO{sub 3}){sub 2}F{sub 9} crystallizes in space group C2/c with the lattice parameters a=2028.2(4) pm, b=602.5(2) pm, c=820.4(2) pm, and beta=100.63(3){sup o} (Z=4). Three different ytterbium cations can be identified in the crystal structure, each coordinated by nine fluoride and oxygen anions. None of the five crystallographically independent fluoride ions is coordinated by boron atoms, solely by trigonally-planar arranged ytterbium cations. In close proximity to the above mentioned compounds RE{sub 3}(BO{sub 3}){sub 2}F{sub 3} (RE=Sm, Eu, Gd) and Gd{sub 2}(BO{sub 3})F{sub 3}, Yb{sub 5}(BO{sub 3}){sub 2}F{sub 9} can be described via alternating layers with the formal compositions 'YbBO{sub 3}' and 'YbF{sub 3}' in the bc-plane. - Graphical abstract: High-pressure/high-temperature synthesis (multianvil technique) led to the first ytterbium fluoride borate Yb{sub 5}(BO{sub 3}){sub 2}F{sub 9}, built up from isolated BO{sub 3}-groups. The compound shows structural relations to the known rare-earth fluoride borates RE{sub 3}(BO{sub 3}){sub 2}F{sub 3} (RE=Sm, Eu, Gd) and Gd{sub 2}(BO{sub 3})F{sub 3}.

Haberer, Almut [Institut fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Universitaet Innsbruck, Innrain 52a, A-6020 Innsbruck (Austria); Huppertz, Hubert, E-mail: hubert.huppertz@uibk.ac.a [Institut fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Universitaet Innsbruck, Innrain 52a, A-6020 Innsbruck (Austria)

2009-04-15

198

Cdigo Candidato Inscrio TM1 ANICETO JOZIEL RABELO GOMES ANDRADE 790  

E-print Network

LIMA COSTA 53 TM1 CÍCERO DE OLIVEIRA ALVES 792 TM1 CLAUDIO LENON SILVA NUNES 1427 TM1 CLEZIO PEREIRA CORR�A 1003 TM2 SILVIO ANTONIO DE BRITO PEREIRA 220 TM3 EDIL JAMES DE JESUS NASCIMENTO 149 TM3 GLEUDSON KHRISTHIANO LEMOS DA ROCHA SOUZA 1 TM4 MATHEUS DA SILVA RABELO 896 TM4 RAPHAEL PEREIRA DA FONSECA 1481 TM4

199

TORR TM DE-OILING TECHNOLOGY  

E-print Network

he TORR TM de-oiling technology, with its small footprint and ability to replace less efficient de-oiling equipment, offers the best available process in the treatment of produced water for offshore producers and operators. The TORR TM technology exceeds today’s discharge regulations and will address future regulations. The scaleable technology addresses future increases in water cut. Adding compact TORR TM vessels requires very little real estate when water cuts increase. FEATURES Small footprint and low weight 1000 ppm down to discharge regulation Better polishing for reinjection applications Removes and recovers oil droplets larger than 2 microns Maximum flow rate per vessel of 60,000 BWPF Same high de-oiling efficiency during production start-up periods No additional treatment required for recovered oil Minimal pressure drop and maintenance and minimal operation costs Recovered hydrocarbons can be <0.5 % BSW High flow rate turndown No moving internal parts No added heat or chemicals Operational temperatures up to 90?C Solids handing capabilities Reduced process complexityTECHNOLOGY The TORR TM process consists of two inline pressure vessels, and an optional third vessel can be used as a standby. Produced water enters the TORR TM unit for treatment and then passes through the core of multiple continuous coalescing elements. The continuous coalescing element adsorbs the small oil droplets, coalesces them to large oil globules and then desorbs them. Gravity separation principles remove these large coalesced globules, which then rise to the top of the vessel. Any solution gas accumulating with the oil at the top of the vessel will be safely recovered. The oil and/or gas collected at the top of the vessel are recuperated and returned to a suitable collection unit. The TORR TM technology treated produced water exceeds discharge regulations.

unknown authors

200

Theoretical investigation of CO adsorption on TM-doped (MgO) 12 (TM = Ni, Pd, Pt) nanotubes  

NASA Astrophysics Data System (ADS)

CO adsorption on TM-doped magnesia nanotubes (TM = Ni, Pd and Pt) have been studied by using density functional theory. Our calculation results show that CO favors adsorption on TM-doped magnesia nanotubes in the form of C atom bonding with TM atom. Fukui indices analysis clearly exhibits that doping of impurity TM atom allows for a noticeably enhancement of nucleophilic reactivity ability of magnesia nanotube. The adsorption energies demonstrate that CO molecule is more strongly bound on the 3-fold TM atoms than the 4-fold TM atoms. This finding is well confirmed by TM-C bond length, charge transfer and C-O vibrational frequency. The high adsorption energy of 2.55 eV is found when CO adsorbs on 3-fold Pt in Pt-doped magnesia nanotubes, implying the kind of the doping TM atom has a significant influence on the chemical reactivity.

Yang, Mingxia; Zhang, Yonghong; Huang, Shiping; Liu, Hui; Wang, Peng; Tian, Huiping

2011-12-01

201

High-spin states in Yb156 and structure evolutions at large angular momenta in even-A Yb isotopes  

NASA Astrophysics Data System (ADS)

High-spin states of Yb156 have been studied via the Sm144(O16,4n)Yb156 fusion-evaporation reaction at beam energy 102 MeV. The positive-parity yrast band and negative-parity cascade have been extended up to higher-spin states, respectively. In the present work, the negative-parity sequence above the 25- state was found to be irregular and fragment into many parallel branches. This pattern may related to the excitation from the nucleon in the Z=64,N=82 core. The characteristics of alignment plot and E-GOS curve for the positive-parity yrast sequence in Yb156 indicate that this nucleus may undergo an evolution from quasivibrational to quasirotational structure with increasing angular momentum. Based on a systematic summary of the available experimental alignments for the even-A Yb156,158,160,162,164 isotopes, the structural evolutions induced by the increase in angular momentum, as well as by the change in neutron numbers, in these even-A Yb isotopes have been discussed in comparison with the cranked Woods-Saxon-Strutinsky calculations by means of total-Routhian-surface (TRS) methods.

Li, Z. Y.; Hua, H.; Wang, S. Y.; Meng, J.; Li, Z. H.; Li, X. Q.; Xu, F. R.; Liu, H. L.; Zhang, S. Q.; Ye, Y. L.; Jiang, D. X.; Zheng, T.; Ma, L. Y.; Lu, F.; Fan, F. Y.; Han, L. Y.; Wang, H.; Xiao, J.; Chen, D.; Fang, X.; Lou, J. L.; Zhou, S. G.; Zhu, L. H.; Wu, X. G.; Li, G. S.; He, C. Y.; Liu, Y.; Li, X. Q.; Hao, X.; Pan, B.; Li, L. H.

2008-06-01

202

Structure change of 156Yb at high-spin states  

NASA Astrophysics Data System (ADS)

High-spin states of 156Yb have been studied via the 144Sm(16O,4n)156Yb fusion-evaporation reaction at beam energy 102 MeV. The positive-parity yrast band and negative-parity cascade have been extended up to higher-spin states, respectively. The characteristics of the negative-parity sequence above the 25- state may related to the excitation from the nucleon in the Z = 64, N = 82 core. The E-GOS curve for the positive-parity yrast sequence in 156Yb indicate that this nucleus may undergo an evolution from quasivibrational to quasirotational structure with increasing angular momentum. The Cranked Woods-Saxon-Strutinsky calculations by means of Total-Routhian-Surface (TRS) methods has been made to understand this structure change.

Hua, Hui; Li, Zhong-Yu; Wang, Shou-Yu; Meng, Jie; Li, Zhi-Huan; Li, Xiang-Qing; Xu, Fu-Rong; Liu, Hong-Liang; Zhang, Shuang-Quan; Zhou, Shan-Gui; Ye, Yan-Lin; Jiang, Dong-Xing; Zheng, Tao; Zhu, Li-Hua; Wu, Xiao-Guang; Li, Guang-Sheng; He, Chuang-Ye; Ma, Li-Ying; Lu, Fei; Fan, Feng-Ying; Han, Li-Ying; Wang, He; Xiao, Jun; Li, Xue-Qin; Chen, Dong; Fang, Xiao; Lou, Jian-Lin; Liu, Ying; Hao, Xin; Pan, Bo; Li, Li-Hua

2009-03-01

203

Investigation of ?-induced reactions on the p nucleus Yb168  

NASA Astrophysics Data System (ADS)

Cross sections for the Yb168(?,?)Hf172 and Yb168(?,n)Hf171 reactions were measured by means of the activation method using ? particles with energies between 12.9 MeV and 15.1 MeV. The spectroscopy of the ? rays emitted by the reaction products was performed using three different HPGe detector types, namely clover-type high-purity germanium detectors, a low-energy photon spectrometer detector, and a coaxial high-purity germanium detector. The results were compared to Hauser-Feshbach statistical model calculations. Within certain assumptions, astrophysical conclusions could be drawn concerning the production of the p nucleus Yb168. The data in this work can serve as a contribution to the current very fragmentary experimental data base for charged-particle induced reactions. In addition, the absolute intensity for nine ?-ray transitions following the electron capture decay of Hf171 could be derived.

Netterdon, L.; Demetriou, P.; Endres, J.; Giesen, U.; Kiss, G. G.; Sauerwein, A.; Szücs, T.; Zell, K. O.; Zilges, A.

2013-10-01

204

Investigation on luminescence properties of Er3+Yb3+Tm3+ co-doped Gd2O3 hollow microspheres  

Microsoft Academic Search

The Gd2O3 hollow microspheres have been successfully fabricated via carbonaceous polysaccharide microspheres as templates and urea as a precipitating agent, which involved the deposition of an inorganic coating on the surface of carbon microsphere, followed by heat treated 800°C for 4h. The obtained high uniform Gd2O3 microspheres with a spherical shape and hollow structure are uniform in size and distribution.

Fang Xu; Wan-Lei Han; Xiao-Bo Liu; Ying-Lin Song

2011-01-01

205

The polygallides: Yb{sub 3}Ga{sub 7}Ge{sub 3} and YbGa{sub 4}Ge{sub2}.  

SciTech Connect

Yb{sub 3}Ga{sub 7}Ge{sub 3} and YbGa{sub 4}Ge{sub 2} were obtained from reactions of Yb and Ge in excess liquid gallium. The crystal structure of Yb{sub 3}Ga{sub 7}Ge{sub 3} was refined using X-ray and neutron diffraction data on selected single crystals. Yb{sub 3}Ga{sub 7}Ge{sub 3} crystallizes in the monoclinic space group C2/c with lattice constants a = 12.2261(20) {angstrom}, b = 10.7447(20) {angstrom}, c = 8.4754(17) {angstrom} and {beta} = 110.288(30){sup o} (neutron diffraction data). The crystal structure of Yb{sub 3}Ga{sub 7}Ge{sub 3} is an intergrowth of planar layers of YbGa{sub x}Ge{sub y} and puckered layers of (Ge)n. YbGa{sub 4}Ge{sub 2} crystallizes in a modified PuGa{sub 6} structure type in the tetragonal polar space group I4cm with lattice constants a = b = 5.9874(6) {angstrom} and c = 15.1178(19) {angstrom}. The structure of YbGa{sub 4}Ge{sub 2} is an intergrowth of puckered Ga layers and puckered Ga{sub x}Ge{sub y} layers with Yb atoms residing within the channels formed by the connection of the two layers. Physical properties, resistivity ({rho}), magnetic susceptibility ({chi}) and specific heat (C) were measured for Yb{sub 3}Ga{sub 7}Ge{sub 3}. No magnetic ordering was observed. It was found that at low temperatures, {rho} varied as T{sup 2} and C{alpha}T, indicating Fermi-liquid regime in Yb{sub 3}Ga{sub 7}Ge{sub 3} at low temperatures.

Peter, S. C.; Malliakas, C. D.; Nakotte, H.; Kothapilli, K.; Rayaprol, S.; Schultz, A. J.; Kanatzidis, M. G. (Materials Science Division); ( XSD); (Northwestern Univ.); (Jawaharlal Nehru Centre for Adv. Sci. Res.); (New Mexico State Univ.); (Los Alamos Nat. Lab.); (UGC-DAE Consortium for Sci. Res.)

2012-03-01

206

CCRS proposal for evaluating LANDSAT-4 MSS and TM data  

NASA Technical Reports Server (NTRS)

The measurement of registration errors in LANDSAT MSS data is discussed as well as the development of a revised algorithm for the radiometric calibration of TM data and the production of a geocoded TM image.

Strome, W. M.; Cihlar, J.; Goodenough, D. G.; Guertin, F. E. (principal investigators); Guindon, B.; Murphy, J.; Butlin, J. M.; Duff, P.; Fitzgerald, A.; Grieve, G.

1984-01-01

207

ORNL/TM-2008/048 Uranyl Nitrate Flow Loop  

E-print Network

ORNL/TM-2008/048 Uranyl Nitrate Flow Loop October 2008 Jennifer L. Ladd-Lively #12;DOCUMENT Government or any agency thereof. #12;ORNL/TM-2008/048 Nuclear Science and Technology Division URANYL NITRATE

Pennycook, Steve

208

Superconducting Wires Enabled by Nanodots wins Nano50TM Award  

E-print Network

Superconducting Wires Enabled by Nanodots wins Nano50TM Award HTS Wires Enabled via 3D Self. · Awarded the Nano 50TM Award from Nanotech Briefs® Magazine for technology. Developers: · A. Goyal S. Kang

209

Open minds. Open doors.TM  

E-print Network

Benefits for Faculty · Long-term Relationship · Consistent funding · Student placement · See the effects research. Now is a good time to get started! #12;Open minds. Open doors.TM John Parmigiani, Director of Industrial Research School of Mechanical

Escher, Christine

210

Neutron Resonance Parameters for Tm-171 (Thulium)  

NASA Astrophysics Data System (ADS)

This document is part of the Supplement containing the complete sets of data of Volume 24 `Neutron Resonance Parameters' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms'. It provides the neutron resonance parameters for the isotope Tm-171 (Thulium).

Sukhoruchkin, S. I.; Soroko, Z. N.

211

E. coli PulserTM Transformation  

E-print Network

E. coli PulserTM Transformation Apparatus Operating Instructions and Applications Guide Catalog or in the U.S. Call 1-800-4BIORAD (1-800-424-6723) #12;Warranty Bio-Rad Laboratories warrants the E. coli ....................................................................................2 Section 2 E. coli Pulser Apparatus Operating Instructions..............................2 Section 3

Lai, Zhi-Chun

212

Open CirrusTM Cloud Computing Testbed  

E-print Network

Open CirrusTM Cloud Computing Testbed: Federated Data Centers for Open Source Systems and Services heterogeneous distributed data centers. Open Cirrus offers a cloud stack consisting of physical and virtual of federated datacenters for open-source systems and services research. As shown in Figure 1, the initial

O'Hallaron, David R.

213

Operational Atmospheric Correction of Landsat TM Data  

Microsoft Academic Search

The recent algorithms developed for biophysical variables assessment require accurate surface reflectance measurements. This article describes algorithms used for atmospheric correction of Landsat Thematic Mapper (TM) data. Atmospheric corrections include Rayleigh scattering, gaseous absorption, and aerosol scattering in three visible channels (480 nm, 560 nm, and 660 nm), and the near-infrared channel (830 nm). Atmospheric constituents such as water vapor

Hassan Ouaidrari; Eric F. Vermote

1999-01-01

214

ORNL/TM-2012/196 Sustainable  

E-print Network

ORNL/TM-2012/196 2012Annual Report Sustainable Transportation Program #12;DOCUMENT AVAILABILITY Sustainable Transportation Program Date Published: September 2013 Prepared by OAK RIDGE NATIONAL LABORATORY contract DE-AC05-00OR22725 #12;#12;Table of Contents iii ORNL Sustainable Transportation Program Table

Pennycook, Steve

215

:>':. '*>3 1 /? ORNL/TM-8022  

E-print Network

:>':. '*>3 1 /? ORNL/TM-8022 ^S] ~/ 3)/:: 60g7b6( Contract No. W-7405-eng-26 Engineering TechnologyOeratus.lotduc:t. r oroes i01iad., fneens tlhatits ue would not intring privatelv owendrghts. Relerece hrein to any

Oak Ridge National Laboratory

216

NeeleyAirTM Density Gauge  

E-print Network

respective displays Top half displays: NeeleyAirTM Density Index Time Bottom half displays: Air Pressure-sized air density gauge. Detects air pressure and temperature Displays the density of the air Allows players Market for the Watch: The air pressure and the temperature is calculated by the pressure and temperature

Zhang, Junshan

217

NASA/TM--2001210880 Photographic Analysis Technique  

E-print Network

NASA/TM--2001­210880 Photographic Analysis Technique for Assessing External Tank Foam Loss Events T'Farrell United Space Alliance, Huntsville, Alabama June 2001 #12;Since its founding, NASA has been dedicated to the advancement of aeronautics and space science. The NASA Scientific and Technical Information (STI) Program

Christian, Eric

218

August 2002 NASA/TM--2002211612  

E-print Network

August 2002 NASA/TM--2002­211612 Pickup Ions at Dione and Enceladus E. Sittler, R.E. Johnson, S. Jurac, J. Richardson, M. McGrath, F. Crary, D. Young, and J.E. Nordholt #12;The NASA STI Program Office ... in Profile Since its founding, NASA has been dedicated to the advancement of aeronautics and space science

Richardson, John

219

Affinity Chromatography Media CellufineTM Sulfate  

E-print Network

, chondroitin sulfate or heparin. Matrex Cellufine Sulfate consists of a rigid spherical cellulose matrix of 3Affinity Chromatography Media Matrex® CellufineTM Sulfate For Concentration, Purification and viral or microbial antigens. Matrex Cellufine Sulfate affinity media is a simple, rapid and effective

Lebendiker, Mario

220

Apollo 324TM PrepX SPIA  

E-print Network

Apollo 324TM System PrepX SPIA® RNA-Seq Library Protocol #12;© Copyright 2012, IntegenX Inc. All no responsibility for any errors that may appear in this document. RESEARCH USE ONLY The Apollo 324 System and conditions of sale. TRADEMARKS Apollo 324, BeadX and PrepX are trademarks of IntegenX Inc. Agencourt, AMPure

221

The optical properties of Yb3+ ions in LiTaO3:Nd,Yb crystals  

Microsoft Academic Search

3+   ions excited by energy transfer from Nd3+ ions in LiTaO3:Nd,?Yb crystals are presented. The emission band of Yb3+ ions is broad, due to the strong phonon-coupling and to the relative large Stark-splitting of the ground 2F7\\/2 multiplet. The emission cross-section was evaluated by the reciprocity method, and a value of 0.53×10-20 cm2 was obtained. The gain coefficients derived for the inversion

I. Sokólska; W. Ryba-Romanowski; S. Golab; T. Lukasiewicz

1997-01-01

222

Thermoelectric properties of Yb-filled CoSb3 skutterudites  

NASA Astrophysics Data System (ADS)

Yb-filled skutterudites Yb z Co4Sb12 (z = 0, 0.1, 0.2, 0.3, 0.4) were prepared by encapsulated melting and hot pressing. The filling effects of Yb on the transport and the thermoelectric properties of the skutterudites were examined. In the case of z ? 0.3, a secondary phase (YbSb2) was formed, indicating that the filling fraction limit of Yb was z = 0.2 - 0.3. The intrinsic CoSb3 had a high positive Seebeck coefficient, but Yb-filled CoSb3 exhibited a negative Seebeck coefficient. In the case of z ? 0.1, the maximum absolute value of the Seebeck coefficient was | -231| ?VK-1, and in the case of z ? 0.2, the absolute value of the Seebeck coefficient increased with increasing temperature. The electrical conductivity increased and the Seebeck coefficient decreased with increasing Yb filling content due to the increased carrier concentration. The thermal conductivity was reduced significantly by Yb filling, mainly due to a decrease in the lattice thermal conductivity. Also, the lattice thermal conductivity decreased with increasing Yb filling content, indicating that the phonon scattering was caused by the rattling of Yb fillers in the voids of the skutterudite structure. Yb0.2Co4Sb12 showed the highest figure of merit of 1.0 at 823 K.

Park, Kwan-Ho; Seo, Won-Seon; Shin, Dong-Kil; Kim, Il-Ho

2014-08-01

223

Relative radiometric calibration of LANDSAT TM reflective bands  

NASA Technical Reports Server (NTRS)

Raw thematic mapper (TM) calibration data from pre-launch tests and in-orbit acquisitions from LANDSAT 4 and 5 satellites are analyzed to assess the radiometric characteristics of the TM sensor. A software program called TM radiometric and algorithmic performance program (TRAPP) was used for the majority of analyses. Radiometric uncertainty in the final TM image originates from: (1) scene variability (solar irradiance and atmospheric scattering); (2) optical and electrical variability of the sensor; and (3) variability introduced during image processing.

Barker, J. L.

1984-01-01

224

Efficient, broadly tunable, laser-pumped Tm:YAG and Tm:YSGG CW lasers  

Microsoft Academic Search

Broadly tunable Tm:YAG and Tm:YSGG (Y3Sc2Ga3O12) lasers are described in which smooth tuning is achieved due to overlapping transitions between phonon-broadened crystal field Stark layers. For the tunable lasers reported here, the upper laser level is one of the 9 3H4 Stark levels, and the lower laser level is one of the 13 3H6 levels. The total bandwidth of fluorescence,

R. C. Stoneman; L. Esterowitz

1990-01-01

225

Sensitization of Pr3+ ions by Eu2+ ions in CaF2 thin films deposited by evaporation  

NASA Astrophysics Data System (ADS)

In the present article, we analyse the possibility of sensitizing the 3Pj levels of Pr3+ ion with Eu2+ ion in CaF2 thin film deposited by evaporation. Indeed, the forbidden nature of the 4f-4f transition of Pr3+ ion makes its absorption too weak for thin film applications, while materials doped with the Pr3+-Yb3+ couple are promising candidates for the achievement of efficient down-converter systems and could allow strong reduction of thermalization losses in silicon solar cells.

Guille, A.; Pereira, A.; Bensalah-Ledoux, A.; Moine, B.; Novotný, M.; Bulí?, J.; Fitl, P.; Lan?ok, J.

2013-11-01

226

Pioneers--The "Engineering byDesign[TM]" Network  

ERIC Educational Resources Information Center

This article discusses the standards-based instruction model, Engineering byDesign[TM] (EbD), and a network of teachers called the Engineering byDesign[TM] Network. Engineering byDesign[TM] is the only standards-based national model for Grades K-12 that delivers technological literacy which was developed by the International Technology Education…

Burke, Barry N.

2006-01-01

227

Giant negative magnetoresistance effect in PbTe(Yb,Mn)  

Microsoft Academic Search

We report on the observation of the giant negative magnetoresistance effect in PbTe doped simultaneously with Yb and Mn. In some impurity concentration range, the sample resistance at the liquid helium temperature drops by about three orders of magnitude when the magnetic field increases up to 5-6 T, with subsequent rise by about one order of magnitude as the field

I. I. Ivanchik; D. R. Khokhlov; A. V. Morozov; A. A. Terekhov; E. I. Slyn'ko; V. I. Slyn'ko; A. de Visser; W. D. Dobrowolski

2000-01-01

228

An Exchange Hamiltonian for Yb2Ti2O7  

NASA Astrophysics Data System (ADS)

Yb2Ti2O7 is a pyrochlore material with many strange properties at low temperature. Specific heat measurements on this material find evidence for a first order phase transition at a temperature of Tc 240 mK, but several experiments fail to find any evidence of long range order below Tc. In order to understand the behaviour of the magnetic moments of the Yb^3+ ions below Tc it is necessary to quantift how they interact. I will present work based on using diffuse neutron scattering measurements to find a magnetic interaction Hamiltonian for Yb2Ti2O7. We propose a Hamiltonian based on all of the symmetry allowed interactions on the pyrochlore lattice, along with long-range dipolar interactions. Using the energies of the symmetry allowed nearest-neighbor exchange interactions as free parameters, we perform simulated annealing to minimize the difference between experimental neutron scattering and neutron scattering computed from our exchange Hamiltonian using the random phase approximation. I will present the results of this fitting, and discuss the predictions of the resulting model for the behaviour of Yb2Ti2O7, including calculations of the local susceptibility.

Thompson, Jordan; McClarty, Paul; Rønnow, Henrik; Regnault, Louis-Pierre; Sorge, Andreas; Gingras, Michel

2011-03-01

229

Multimodal microscopy with sub-30 fs Yb fiber laser oscillator  

PubMed Central

Nonlinear optical microscopy with sub-30 fs pulses from an Yb-fiber laser, approximately three times shorter than typical fiber laser pulses, leads to an order of magnitude brighter third harmonic generation imaging. Multiphoton fluorescence, second and third harmonic generation modalities are compared on stained microspheres and unstained biological tissues. PMID:22808444

Nie, Bai; Saytashev, Ilyas; Chong, Andy; Liu, Hui; Arkhipov, Sergey N.; Wise, Frank W.; Dantus, Marcos

2012-01-01

230

700-W single transverse mode Yb-doped fiber laser  

Microsoft Academic Search

We demonstrate 700-W fundamental mode beam from Yb-doped fiber laser operating at 1092 nm. Coiling 20-mum diameter and 0.06 NA core fiber into 15-cm diameter spool eliminates higher-order modes through distributed mode filtering

C.-H. Liu; A. Galvanauskas; B. Ehlers; F. Doerfel; S. Heinemann; A. Carter; K. Tanakala; J. Farroni

2004-01-01

231

Intermediate valence in Yb Intermetallic compounds Jon Lawrence  

E-print Network

ion model: Two nearly-degenerate localized configurations form hybridized w.f.: a [4f13(5d6s)3> + b [4 configurations: conduction electrons hop on and off the 4f impurity orbital. Hybridization strength = V2 where1 Intermediate valence in Yb Intermetallic compounds Jon Lawrence University of California, Irvine

Lawrence, Jon

232

Reliability and Validity of the Zephyr[TM] BioHarness[TM] to Measure Respiratory Responses to Exercise  

ERIC Educational Resources Information Center

The Zephyr[TM] BioHarness[TM] (Zephyr Technology, Auckland, New Zealand) is a wireless physiological monitoring system that has the ability to measure respiratory rate unobtrusively. However, the ability of the BioHarness[TM] to accurately and reproducibly determine respiratory rate across a range of intensities is currently unknown. The aim of…

Hailstone, Jono; Kilding, Andrew E.

2011-01-01

233

Electron Scattering From Laser Excited Ba and Yb Atoms  

NASA Astrophysics Data System (ADS)

Inelastic and elastic electron scattering out of the excited states of Ba and Yb has been studied at low collision energies. We present measurements (at 10 eV and 20 eV collision energies) of differential cross sections and orientation parameters for elastic scattering out of the 6 ^1P1 and 5 D levels of Ba and for inelastic scattering out of the 6 ^3P1 level of Yb to higher lying ^3D and ^3S levels. Collision studies are carried out using a momentum selected incident electron beam with momentum resolved scattered electron detection and excited atomic target populations generated by resonant laser radiation. To a good approximation, Ba and Yb are heavy two-electron systems comprising filled, approximately inert cores ([Xe] for Ba and [Xe]4f^14 for Yb) with two-electron 6s^2 valence configurations (in the ground state). Theoretical determinations of low-energy electron scattering parameters for these atoms, based on convergent close coupling and first order perturbative formalisms, have met with success in many cases. Such calculations have been applied to inelastic scattering from 6S, 5D and 6P target states in Ba and the 6S ground state in Yb (refs 1,2). Extension of previous experimental investigations to the new scattering processes described in this work will further test the efficacy of available theoretical methods. 1. I. Bray et al. J.Phys.B:At.Mol.Opt.Phys. 35 R117 (2002) 2. B Predojevic et al. J. Phys. B: At. Mol. Opt. Phys. 38 3489 (2005)

Zetner, Peter; Hein, Jeff

2007-06-01

234

Relativistic many-body calculations of van der Waals coefficients for Yb-Li and Yb-Rb dimers  

NASA Astrophysics Data System (ADS)

We derive the relativistic formulas for the van der Waals coefficients of Yb-alkali-metal dimers that correlate to ground and excited separated-atom limits. We calculate C6 and C8 coefficients of particular experimental interest. We also derive a semiempirical formula that expresses the C8 coefficient of heteronuclear A +B dimers in terms of the C6 and C8 coefficients of homonuclear dimers and the static dipole and quadrupole polarizabilities of the atomic states A and B. We report results of calculation of the C6 coefficients for the Yb-Rb 3P1o+5s2S1/2 and 1S0+5p2P1/2o dimers, and the C8 coefficients for the Yb-Li 1S0+2s2S1/2 and Yb-Rb 1S0+5s2S1/2 dimers. Uncertainties are estimated for all predicted properties.

Porsev, S. G.; Safronova, M. S.; Derevianko, A.; Clark, Charles W.

2014-02-01

235

Relativistic many-body calculations of van der Waals coefficients for Yb-Li and Yb-Rb dimers  

E-print Network

We derive the relativistic formulas for the van der Waals coefficients of Yb-alkali dimers that correlate to ground and excited separated-atom limits. We calculate $C_6$ and $C_8$ coefficients of particular experimental interest. We also derive a semi-empirical formula that expresses the $C_8$ coefficient of heteronuclear $A+B$ dimers in terms of the $C_6$ and $C_8$ coefficients of homonuclear dimers and the static dipole and quadrupole polarizabilities of the atomic states $A$ and $B$. We report results of calculation of the $C_6$ coefficients for the Yb-Rb $^3/!P_1^o+5s\\, ^2/!S_{1/2}$ and $^1/!S_0+5p\\, ^2/!P^o_{1/2}$ dimers, and the $C_8$ coefficients for the Yb-Li $^1/!S_0+2s\\, ^2/!S_{1/2}$ and Yb-Rb $^1/!S_0+5s\\, ^2/!S_{1/2}$ dimers. Uncertainties are estimated for all predicted properties.

Porsev, S G; Derevianko, A; Clark, Charles W

2014-01-01

236

Post-adsorption process of Yb phosphate nano-particle formation by Saccharomyces cerevisiae  

NASA Astrophysics Data System (ADS)

In this study, we have investigated the post-adsorption process of ytterbium (Yb) phosphate nano-particle formation by Saccharomyces cerevisiae (yeast). The yeast grown in P-rich medium were exposed to 1.44 × 10-4 mol/L Yb(III) solution for 2-120 h, and 2 months at 25 ± 1 °C at an initial pH of 3, 4, or 5, respectively. Ytterbium concentrations in solutions decreased as a function of exposure time. Field-emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (FESEM), transmission electron microscopy (TEM), and synchrotron-based extended X-ray absorption fine structure (EXAFS) analyses revealed that nano-sized blocky Yb phosphate with an amorphous phase formed on the yeast cells surfaces in the solutions with Yb. These nano-sized precipitates that formed on the cell surfaces remained stable even after 2 months of exposure at 25 ± 1 °C around neutral pHs. The EXAFS data revealed that the chemical state of the accumulated Yb on the cell surfaces changed from the adsorption on both phosphate and carboxyl sites at 30 min to Yb phosphate precipitates at 5 days, indicating the Yb-phosphate precipitation as a major post-adsorption process. In addition, the precipitation of Yb phosphate occurred on cell surfaces during 7 days of exposure in Yb-free solution after 2 h of exposure (short-term Yb adsorption) in Yb solution. These results suggest that the released P from the inside of yeast cells reacted with adsorbed Yb on cell surfaces, resulting in the formation of Yb precipitates, even though no P was added to the exposure solution. In an abiotic system, the EXAFS data showed that the speciation of sorbed Yb on the reference materials, carboxymethyl cellulose and Ln resin, did not change even when the Yb was exposed to P solution, without forming Yb phosphate precipitates. This result strongly suggests that the cell surface of the yeast plays an important role in the Yb-phosphate precipitation process, not only as a carrier of the functional groups but also as a substrate inducing the nucleation of phosphate nanoparticles. Stable nano-sized Yb phosphate precipitates formed on yeast cell surfaces in the present study, which implies that this post-adsorption nano-particle formation process caused by microbial cells should be one of the important processes governing the long-term migration of heavy rare earth elements and presumably trivalent actinides in geological repository.

Jiang, MingYu; Ohnuki, Toshihiko; Tanaka, Kazuya; Kozai, Naofumi; Kamiishi, Eigo; Utsunomiya, Satoshi

2012-09-01

237

Magnetization reversal and Yb3+/Cr3+ spin ordering at low temperature for perovskite YbCrO3 chromites  

NASA Astrophysics Data System (ADS)

The temperature dependence of the dc magnetization and the specific heat capacity are systematically investigated for the perovskite YbCrO3 chromites. The results show that there exist two complex sequences of magnetic transitions with the characteristics of magnetization reversal and Yb3+/Cr3+ spin ordering at different temperature, respectively. The antiferromagneticlike transition around TN=118 K is attributed to the antiferromagnetic ordering of the Cr3+ spins and a negative magnetization, accompanied with a tendency to the plateau below 10 K caused by the Yb3+ ordering. We obtain the Weiss constant of -197.0 K and an effective moment of 5.99?B for the sum of the free ion values of 4.53?B for Yb3+ and 3.87?B for high-spin Cr3+ from the experiments, which shows an antiferromagnetic interaction and the existence of weak canted antiferromagnetic (CAFM) characteristics. Corresponding to the magnetic phase transition in the Cr sublattice, the specific heat capacity under zero fields exhibits a sharp ?-shape peak near temperature TN, which is depressed and broadened smoothly with the increase in the magnetic field. And a shoulder-shaped Schottky-type anomaly below 12 K is observed in the specific heat capacity curves. This can be interpreted by accounting for the molecular field approximation by assuming that the induced polarization of the paramagnetic ytterbium ions is opposite to the ferromagnetic moment of the chromium ions. According to the results of the zero fields cooling and the field cooling magnetization, the possible existence of spin ordering for the Yb3+ moments can be predicted.

Su, Yuling; Zhang, Jincang; Feng, Zhenjie; Li, Li; Li, Beizhan; Zhou, Yun; Chen, Zhenping; Cao, Shixun

2010-07-01

238

Determination of the 151Eu(n,?)152Eu and 153Eu(n,?)154Eu Reaction Cross Sections at Thermal Neutron Energy  

NASA Astrophysics Data System (ADS)

We have measured partial ?-ray cross sections following neutron capture in enriched 151Eu and 153Eu targets at the cold-neutron-beam facility of the Budapest Research Reactor. The cross sections were standardized using a stoichiometric natEuCl3 target with the well-known 1951-keV ?-ray cross section from the 35Cl(n,?)36Cl reaction at the cold-neutron-beam facility of the Garching Research Reactor. The ?-ray cross sections were corrected for effective g-factors. These data were combined with the structural information of 152Eu and 154Eu given in the Evaluated Nuclear Structure Data File to produce capture ?-ray level schemes. The total radiative capture cross sections of the 151Eu(n,?)152Eu and 153Eu(n,?)154Eu reactions were determined by summing the experimental transition intensities from known levels with simulated intensities of transitions from higher excitations to the ground- or metastable-state. The individual 151Eu(n,?)152Eu and 151Eu(n,?)152gEu reaction cross sections disagree with values in the literature. However, the total cross section of the 151Eu(n,?)152Eu reaction does agree with those values. Also, our deduced cross section for the 153Eu(n,?)154Eu reaction closely follows the data in the literature. These results are supported by an earlier standardization experiment done at the Budapest Research Reactor using a target of Eu2O3 solution in H2SO4.

Basunia, M. S.; Firestone, R. B.; Révay, Zs.; Choi, H. D.; Belgya, T.; Escher, J. E.; Hurst, A. M.; Krti?ka, M.; Szentmiklósi, L.; Sleaford, B.; Summers, N. C.

2014-05-01

239

PowerformerTM-the prototype and beyond  

Microsoft Academic Search

The general concept of PowerformerTM, a high voltage generator connected directly to the grid, is described. By using high-voltage cable technology it is possible to confine the electrical field to inside the winding and reach high voltage levels on the generator terminals. The prototype high-voltage generator rated at 45 kV, 11 MVA has been operating since spring 1998. The accumulated

M. Leijon; F. Owman; S. G. Johansson; T. Karlsson; S. Lindahl; C. Parkegren; S. Thoren

2000-01-01

240

Dopant dependent stability of Co n TM+ (TM = Ti, V, Cr, and Mn) clusters  

NASA Astrophysics Data System (ADS)

In this paper, we present a photofragmentation study of mass-selected transition metal-doped cobalt cluster cations Co n TM+ ( n = 8-18, TM = Ti, V, Cr, and Mn). Time-of-flight spectra recorded after laser excitation of mass-selected clusters in the gas phase show that the evaporation of a cobalt atom is the most facile dissociation channel for clusters with TM = Ti and V, suggesting an enhanced stability of the doped clusters compared to the bare ones. In contrast, for Co n TM+ with TM = Cr and Mn, the loss of the dopant atom is found to be the preferred dissociation channel. Co13Cr+ is a notable exception and favors dissociation by loss of a neutral Co atom. It is implied that substituting Mn and Cr generally destabilizes the cobalt clusters with the exception of Co12Cr+, which is relatively more stable than Co{13/+}. Additional measurements of V n Co+ ( n = 9-16) show that the loss of a Co atom is still the most facile dissociation channel, which is in agreement with the predicted stronger V-V bond compared to the V-Co one.

Tung, Nguyen Thanh; Janssens, Ewald; Lievens, Peter

2014-03-01

241

Electronic structure and f-orbital occupancy in Yb-substituted CeCoIn5  

SciTech Connect

The local structure and 4f orbital occupancy have been investigated in Ce{sub 1?x}Yb{sub x}CoIn{sub 5} via Yb L{sub III}-edge extended x-ray absorption fine structure (EXAFS), Ce and Yb L{sub III}-edge x-ray absorption near-edge structure (XANES), and angle-resolved photoemission spectroscopy (ARPES) measurements. Yb(III) (4f{sup 13}) is the hole analog of Ce(III) (4f{sup 1}). Yb is found to be strongly intermediate-valent in Ce{sub 1?x}Yb{sub x}CoIn{sub 5} throughout the entire doping range, including pure YbCoIn{sub 5}, with an f-hole occupancy for Yb of n{sub f} ? 0.3 (i.e. Yb{sup 2.3+}), independent of Yb concentration and independent of temperature down to T = 20 K. In contrast, the f-electron orbital occupancy for Ce remains close to 1 for all Yb concentrations, suggesting that there is no mutual influence on n{sub f} between neighboring Ce and Yb sites. Likewise, ARPES measurements at 12 K have found that the electronic structure along {Gamma} ? X is not sensitive to the Yb substitution, suggesting that the Kondo hybridization of Ce f electrons with the conduction band is not affected by the presence of Yb impurities in the lattice. The emerging picture is that in Ce{sub 1?x}Yb{sub x}CoIn{sub 5} there are two networks, interlaced but independent, that couple to the conduction band: one network of Ce ions in the heavy-fermion limit, one network of Yb ions in the strongly intermediate-valent limit. The robustness of the local and electronic structure to doping suggests the absence of charge transfer between the Ce and Yb ions, and may explain the relative robustness of superconductivity for this Ce-site substitution as compared to the In-site substitution.

Booth, C. H.; Durakiewicz, T.; Capan, C.; Hurt, D.; Bianchi, A. D.; Joyce, J.J.; Fisk, Z.

2011-05-03

242

A Revised Periodic Table: With the Lanthanides Repositioned  

Microsoft Academic Search

The lanthanide elements from lanthanum to lutetium inclusive are incorporated into the body of the periodic table. They are\\u000a subdivided into three sub-groups according to their important oxidation states: La to Sm, Eu to Tm, Yb and Lu, so that Eu\\u000a and Yb fall directly below Ba; La, Gd, Lu form a column directly below Y; Ce and Tb fall

Michael Laing

2005-01-01

243

New EU regulations in endoscopy.  

PubMed

As a result of European unification, new regulations valid within the territory of the European Union (EU) have been negotiated and published. As in other medical fields, the Medical Device Directive (MDD) is the most important new regulation and also effects endoscopy. In a transition period until June 1998, the MDD will be transposed into national law by the member states of the EU. Compliance with the MDD and other European regulations is indicated by the CE mark affixed to the product. PMID:8565892

Wächter, M; Diekjobst, T

1995-09-01

244

Improvement of Yb3+ doped optical fiber preforms by using MCVD method  

Microsoft Academic Search

This communication describes the fabrication of Yb doped silica preforms by modified chemical vapor deposition (MCVD) method using Yb(C11H19O2)3 and AlCl3 in vapor phase. In order to investigate the optical quality of the preforms a systematic spectroscopic study was carefully carried out on various samples with different Yb and Al doping levels. In this way, the influence of the preforms

V. Petit; E. H. Sekiya; T. Okazaki; R. Bacus; P. Barua; B. Yao; K. Ohsono; K. Saito

2008-01-01

245

Optimization of the cooling profile to achieve crack-free Yb:S-FAP crystals  

Microsoft Academic Search

Yb:S-FAP [Yb{sup 3+}:Sr(PO)F] crystals are an important gain medium for diode-pumped laser applications. Growth of 7.0 cm diameter Yb:S-FAP crystals utilizing the Czochralski (CZ) method from SrF-rich melts often encounter cracks during the post growth cool down stage. To suppress cracking during cool down, a numerical simulation of the growth system was used to understand the correlation between the furnace

H Fang; S Qiu; L Kheng; K Schaffers; J Tassano; J Caird; H Zhang

2007-01-01

246

Optical properties of Yb+ 3-doped fibers and fiber lasers at high temperature  

Microsoft Academic Search

Recent advances in power scaling of Yb+ 3-doped fiber lasers to the kilowatt level suggest a need to examine the performance of Yb+ 3-doped silica at temperatures well above ambient. We report experimental results for the absorption coefficient, emission cross-section, fluorescence lifetime, and slope efficiency of a Yb3+-doped large mode area (LMA) silica fiber for temperatures spanning 23 °C-977 °C.

S. W. Moore; T. Barnett; T. A. Reichardt; R. L. Farrow

2011-01-01

247

Optical properties of Yb + 3 -doped fibers and fiber lasers at high temperature  

Microsoft Academic Search

Recent advances in power scaling of Yb+3-doped fiber lasers to the kilowatt level suggest a need to examine the performance of Yb+3-doped silica at temperatures well above ambient. We report experimental results for the absorption coefficient, emission cross-section, fluorescence lifetime, and slope efficiency of a Yb3+-doped large mode area (LMA) silica fiber for temperatures spanning 23°C–977°C. To the best of

S. W. Moore; T. Barnett; T. A. Reichardt; R. L. Farrow

2011-01-01

248

Anisotropic superconductivity in graphite intercalation compound YbC 6  

NASA Astrophysics Data System (ADS)

We report anisotropy of the upper critical field ( Bc2) of an intercalated graphite superconductor YbC 6 ( Tc = 6.5 K) determined from angular dependent magnetoresistance measurements. Though the perpendicular coherence length is much longer than interlayer spacing, measured angular dependences of Bc2 are well fitted by the Lawrence-Doniach model or the Tinkham model, which are known to be applicable to quasi two-dimensional materials or thin films, rather than the effective mass model. This observation is similar to the measurements for the other intercalated graphite superconductor, CaC 6, by Jobiliong et al. [E. Jobiliong, H.D. Zhou, J.A. Janik, Y.-J. Jo, L. Balicas, J.S. Brooks, C.R. Wiebe, Phys. Rev. B 76 (2007) 052511]. A possible explanation for the unexpected applicability of these models is that our YbC 6 samples are synthesized as thin flakes in the host graphite.

Kawai, N. F.; Fukuyama, Hiroshi

2008-12-01

249

Charge Fluctuations and the Valence Transition in Yb under Pressure  

SciTech Connect

We present a dynamical mean field theory study of the valence transition (f{sup 14} {yields} f{sup 13}) in elemental, metallic Yb under pressure. Our calculations reproduce the observed valence transition as reflected in the volume dependence of the 4f occupation. The transition is accelerated by heating, and suggests quasiparticle or Kondo-like structure in the spectra of the trivalent end state, consistent with the early lanthanides. Results for the local charge fluctuations and susceptibility, however, show novel signatures uniquely associated with the valence transition itself, indicating that Yb is a fluctuating valence material in contrast to the intermediate valence behavior seen in the early trivalent lanthanides Ce, Pr, and Nd.

Ylvisaker, E R; Kunes, J; McMahan, A K; Pickett, W E

2009-04-21

250

High efficiency Yb:YAG crystalline fiber-waveguide lasers.  

PubMed

A laser diode (LD) cladding pumped single-mode 1030 nm laser has been demonstrated, in an adhesive-free bonded 40 ?m core Yb:YAG crystalline fiber waveguide (CFW). A laser output power of 13.2 W at a wavelength of 1.03 ?m has been achieved, for an input pump power of 39.5 W. The corresponded laser efficiency is 33.4%. The laser beam quality is confirmed to be near diffraction-limited, with a measured M2=1.02. A LD core pumped single-clad Yb:YAG CFW laser has also been demonstrated with a top-hat laser beam profile, with a laser output power of 28 W and a slope efficiency of 78%. PMID:25361347

Mu, Xiaodong; Meissner, Stephanie; Meissner, Helmuth; Yu, Anthony W

2014-11-01

251

Factors governing Yb magnetism in Yb{sub 0.95}PtIn{sub 2} and other MgCuAl{sub 2}-type structures  

SciTech Connect

The ternary compound 'YbPtIn{sub 2}' has been synthesized and its crystal structure determined using single crystal X-ray diffraction techniques. The compound crystallizes in the MgCuAl{sub 2} structure, a ternary structure type often formed when rare earth metals, Group 10 transition metals, and indium are present in a 1:1:2 ratio. The unit cell is C-centered orthorhombic, space group Cmcm (no. 63) with lattice parameters of a=4.3410(1) A, b=10.3230(2) A, and c=7.8510(2) A. Evidence is found for a substantial non-stoichiometry on the Yb site, in contrast to the Pt and In sites which behave as expected, and it is believed that the stoichiometry of this compound is more properly described as Yb{sub 0.95}PtIn{sub 2}. Magnetic and resistivity measurements reveal that 'YbPtIn{sub 2}' is a weakly interacting, non-magnetic metal exclusively containing Yb{sup 2+}, and with a resistivity ({rho}) varying from 34 {mu}{Omega} cm at room temperature to a residual resistivity {rho}{sub 0} of 23 {mu}{Omega} cm at 1.8 K. Density functional theory calculations suggest that the observed diamagnetic Yb behavior is expected for this compound, but that certain substitutions on the Pt or In site could help stabilize magnetic Yb{sup 3+} and potentially induce heavy fermion behavior. - Graphical abstract: The crystal structure, magnetic behavior, and temperature-dependent resistivity of the new ternary compound Yb{sub 0.95}PtIn{sub 2.} Highlights: Black-Right-Pointing-Pointer Flux growth method used to produce Yb{sub 0.95}PtIn{sub 2} single crystals. Black-Right-Pointing-Pointer Found rare example of non-stoichiometry in a MgCuAl{sub 2}-type structure. Black-Right-Pointing-Pointer The resistivity and diamagnetic response of Yb{sub 0.95}PtIn{sub 2} were modeled. Black-Right-Pointing-Pointer DFT correctly predicts presence of Yb{sup 2+} in Yb{sub 0.95}PtIn{sub 2}. Black-Right-Pointing-Pointer COHP results suggest other MgCuAl{sub 2}-type indides that may contain paramagnetic Yb{sup 3+}.

Malingowski, Andrew C. [Department of Chemistry, State University of New York - Stony Brook, Stony Brook, NY 11794-3400 (United States)] [Department of Chemistry, State University of New York - Stony Brook, Stony Brook, NY 11794-3400 (United States); Kim, Moosung [Department of Physics and Astronomy, State University of New York - Stony Brook, Stony Brook, NY 11794-3800 (United States)] [Department of Physics and Astronomy, State University of New York - Stony Brook, Stony Brook, NY 11794-3800 (United States); Liu, Jue [Department of Chemistry, State University of New York - Stony Brook, Stony Brook, NY 11794-3400 (United States)] [Department of Chemistry, State University of New York - Stony Brook, Stony Brook, NY 11794-3400 (United States); Wu, Liusuo [Department of Physics and Astronomy, State University of New York - Stony Brook, Stony Brook, NY 11794-3800 (United States)] [Department of Physics and Astronomy, State University of New York - Stony Brook, Stony Brook, NY 11794-3800 (United States); Aronson, Meigan C. [Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States) [Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Department of Physics and Astronomy, State University of New York - Stony Brook, Stony Brook, NY 11794-3800 (United States); Khalifah, Peter G., E-mail: kpete@bnl.gov [Department of Chemistry, State University of New York - Stony Brook, Stony Brook, NY 11794-3400 (United States); Department of Chemistry, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)

2013-02-15

252

250 W single-crystal fiber Yb:YAG laser.  

PubMed

We demonstrate an Yb:YAG single-crystal fiber laser with 251 W output power in continuous-wave and an optical efficiency of 44%. This performance can be explained by the high overlap between pump and signal beams brought by the pump guiding and by the good thermal management provided by the single-crystal fiber geometry. The oscillator performance with a reflectivity of the output coupler as low as 20% also shows high potential for power amplification. PMID:22825171

Délen, Xavier; Piehler, Stefan; Didierjean, Julien; Aubry, Nicolas; Voss, Andreas; Ahmed, Marwan Abdou; Graf, Thomas; Balembois, Francois; Georges, Patrick

2012-07-15

253

Surface oxidation of the icosahedral Ag-In-Yb quasicrystal  

Microsoft Academic Search

The oxidation of the high-symmetry surfaces of a single grain icosahedral (i) Ag-In-Yb quasicrystal has been studied using x-ray photoemission spectroscopy. The oxidation was carried out in vacuum, air, and water. It is found that air exposure results in the same degree of oxidation as exposure to oxygen in vacuum. The oxidation in water is more effective. Among the three

P. J. Nugent; G. Simutis; V. R. Dhanak; R. McGrath; M. Shimoda; C. Cui; A. P. Tsai; H. R. Sharma

2010-01-01

254

Follow-up Photometry of iPTF14yb  

NASA Astrophysics Data System (ADS)

We observed the field around the GRB afterglow candidate iPTF14yb (Cenko et al. ATel #5924) with the DIAFI instrument mounted on the 2.7 m Harlan J. Smith Telescope at McDonald Observatory, Texas. A series of CCD frames using Sloan-g and Sloan-r filters were collected on Feb.27 08:25 UT. The transient has been successfully detected on all frames.

Vinko, J.; Silverman, J. M.; Pooley, D.; Szalai, T.; Robinson, E. L.; Wheeler, J. C.

2014-02-01

255

Thermoelectric and Transport Properties of Yb z Fe4-x Ni x Sb12 Skutterudites  

NASA Astrophysics Data System (ADS)

p-Type Yb z Fe4-x Ni x Sb12 (0.8 ? z ?1.0, and 0.25 ? x ?0.5) skutterudites were prepared, and the effects of Yb filling and Ni substitution on the thermoelectric properties were examined. X-ray diffraction patterns revealed that Yb z Fe4-x Ni x Sb12 skutterudites were synthesized, but small amounts of secondary phases (FeSb2 and Sb) were produced, except for the YbFe3.5Ni0.5Sb12 specimen. This meant that the charge compensation with Ni and the amount of Yb filling should be sufficient to stabilize the skutterudite structure. All specimens had positive Hall coefficients and Seebeck coefficients, and the carrier concentration ranged from 9.80 × 1020 cm-3 to 3.37 × 1021 cm-3. The electrical conductivity decreased and the Seebeck coefficient increased with increasing Yb and Ni contents due to the decreased carrier concentration. The thermal conductivity decreased with increasing Yb and Ni contents, and YbFe3.5Ni0.5Sb12 showed the lowest thermal conductivity. The maximum dimensionless figure of merit achieved was of 0.62 at 723 K for YbFe3.5Ni0.5Sb12, based on the high power factor (2.6 mWm-1 K-2) and the low thermal conductivity (2.9 Wm-1 K-1).

Lee, Woo-Man; Shin, Dong-Kil; Kim, Il-Ho

2014-09-01

256

Characterization of defect luminescence in Yb doped silica fibers: part I NBOHC.  

PubMed

We present an analysis of non-bridging oxygen hole center (NBOHC) defects in Yb-doped silica fibers. Red photoluminescence is observed when several fiber samples are irradiated with green light (532 nm). Both highly Ge-doped and moderately P-doped Yb fibers exhibit red-shifted NBOHC emission spectra while highly Al-doped Yb fibers seem to exhibit NBOHC spectra closer to that of pure silica. NBOHC centers may play a role in the photodarkening process of Yb doped fibers. PMID:18542565

Dragic, Peter D; Carlson, Chad G; Croteau, André

2008-03-31

257

X-RAY ABSORPTION SPECTROSCOPY OF YB3+-DOPED OPTICAL FIBERS  

SciTech Connect

Optical fibers doped with Ytterbium-3+ have become increasingly common in fiber lasers and amplifiers. Yb-doped fibers provide the capability to produce high power and short pulses at specific wavelengths, resulting in highly effective gain media. However, little is known about the local structure, distribution, and chemical coordination of Yb3+ in the fibers. This information is necessary to improve the manufacturing process and optical qualities of the fibers. Five fibers doped with Yb3+ were studied using Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy and X-ray Absorption Near Edge Spectroscopy (XANES), in addition to Yb3+ mapping. The Yb3+ distribution in each fiber core was mapped with 2D and 1D intensity scans, which measured X-ray fluorescence over the scan areas. Two of the five fibers examined showed highly irregular Yb3+ distributions in the core center. In four of the five fibers Yb3+ was detected outside of the given fiber core dimensions, suggesting possible Yb3+ diffusion from the core, manufacturing error, or both. X-ray absorption spectroscopy (XAS) analysis has so far proven inconclusive, but did show that the fibers had differing EXAFS spectra. The Yb3+ distribution mapping proved highly useful, but additional modeling and examination of fiber preforms must be conducted to improve XAS analysis, which has been shown to have great potential for the study of similar optical fi bers.

Citron, Robert; Kropf, A.J.

2008-01-01

258

Differential Control of Interleukin-6 mRNA Levels by Cellular Distribution of YB-1  

PubMed Central

Cytokine production is essential for innate and adaptive immunity against microbial invaders and must be tightly controlled. Cytokine messenger RNA (mRNA) is in constant flux between the nucleus and the cytoplasm and in transcription, splicing, or decay; such processes must be tightly controlled. Here, we report a novel function of Y-box-binding protein 1 (YB-1) in modulating interleukin-6 (IL-6) mRNA levels in a cell type-specific manner. In lipopolysaccharide (LPS)-stimulated macrophages, YB-1 interacts with IL-6 mRNA and actively transports it to the extracellular space by YB-1-enriched vesicles, resulting in the proper maintenance of intracellular IL-6 mRNA levels. YB-1 secretion occurs in a cell type-specific manner. Whereas macrophages actively secret YB-1, dendritic cells maintain it predominantly in the cytoplasm even in response to LPS. Intracellular YB-1 has the distinct function of regulating IL-6 mRNA stability in dendritic cells. Moreover, because LPS differentially regulates the expression of histone deacetylase 6 (HDAC6) in macrophages and dendritic cells, this stimulus might control YB-1 acetylation differentially in both cell types. Taken together, these results suggest a unique feature of YB-1 in controlling intracellular IL-6 mRNA levels in a cell type-specific manner, thereby leading to functions that are dependent on the extracellular and intracellular distribution of YB-1. PMID:25398005

Kang, Sujin; Lee, Taeyun A.; Ra, Eun A.; Lee, Eunhye; Choi, Hyun jin; Lee, Sungwook; Park, Boyoun

2014-01-01

259

[Connection of intracellular protein YB-1 localization in cell cultures of human tumors with multidrug resistance].  

PubMed

In this study, we investigated how the protein YB-1 influenced on the expression of genes coding ABC transporters and on drug resistance in several cell lines, in which originally gene MDR1, coding P-glycoprotein, was not expressed. These populations were significantly different in the presence of mRNA YB-1 and the nature of the intracellular localization of the protein YB-1. However incubation of cells in all studied populations in the culture medium with serum after starvation led to translocation of YB-1 in the cell nucleus. The increase of the number of cells with nuclear localization of YB-1 correlated with increased amount of mRNA YB-1. Processing of cells with drug LY-294,002 by PI3K/Akt inhibitor prevented the translocation of the protein YB-1 into the nuclei of cells, and the cells became more sensitive to the toxic action. Thus, we observed that the signaling pathways involved in control of cell proliferation, in particular a signaling cascade PI3K/Akt were involved in the control of the intracellular localization of YB-1 in cell populations of ovarian cancer, melanoma and human prostate cancer. In these cells the nuclear localization of YB-1 correlated with an expression of MDR and MRP1 DCRP genes and with a sensitivity of cells to a number of drugs. PMID:24260892

Rybalkina, E Iu; Stromskaia, T P; Ovchinnikov, L P; Stavrovskaia, A A

2013-01-01

260

Quasi-millimeter-wave absorption behavior in Y/Yb-stabilized zirconia ceramics  

NASA Astrophysics Data System (ADS)

Broadband dielectric spectra from 10 to 1014 Hz were acquired for 8 mol. % Y2O3/Yb2O3-stabilized zirconia (8YSZ and 8YbSZ) ceramics that related the dipole and ionic polarization losses to the absorption efficiency of electromagnetic irradiation. For 24 GHz irradiation, 8YSZ exhibited a higher absorption efficiency than 8YbSZ, resulting in a higher dielectric loss. The difference in the dielectric loss was interpreted as the difference in the loss of the dipoles originating from the fluctuations in the defect associations (Y'ZrVo ¨ and Yb'ZrVo ¨).

Teranishi, Takashi; Akiyama, Naoki; Ayano, Keiko; Hayashi, Hidetaka; Kishimoto, Akira; Fujimori, Kazuhiro; Hoshina, Takuya; Takeda, Hiroaki; Tsurumi, Takaaki

2012-06-01

261

30-W Yb3+-pulsed fiber laser with wavelength tuning  

NASA Astrophysics Data System (ADS)

We have investigated various pulsed operation regimes of a diode-pumped Yb3+-doped fiber laser with both an acoustooptic filter and a shutter inside the resonator. To imbed the polarization-sensitive acoustooptic-tunable spectral filter into the polarization-nonmaintaining resonator, based on an “isotropic” single-mode fiber without “polarization’ losses, we have used a CaCO3 single-crystal nondispersive thermostable polarization splitter. Stable smooth bell-shaped laser pulses were obtained in the Q-switch generation regime across the entire wavelength tuning band. Their duration depended on the resonator travel time and their repetition rate was determined exclusively by the outer high-frequency generator controlling the acoustooptic shutter. A pulsed laser radiation tuning bandwidth of more than 20-nm at a repetition rate band of 10-100 kHz was observed in the amplification band of the Yb3+-doped fiber. A stable average power of 30 W of the pulsed 70-ns 100-kHz laser radiation in a near Gaussian beam was reached by means of the two-stage amplifier based on Yb3+-doped fibers with an enlarged mode field diameter (14 ?m). The amplifier was pumped by ? = 975 nm CW multimode laser diodes with a maximum average power of 42 W.

Davydov, B. L.; Krylov, A. A.

2007-12-01

262

Reduction of Eu3+ in aluminoborosilicate glasses  

E-print Network

.16.Fh, 61.72.Hh, 61.80.Fe keywords : borosilicate glasses, rare-earth reduction, irradiation1 Reduction of Eu3+ to Eu2+ in aluminoborosilicate glasses under ionizing radiation E. Malchukova, France Abstract Eu2O3-doped aluminoborosilicate glasses were prepared by melting in air at high

Paris-Sud XI, Université de

263

Non-EU Exchange Orientation  

E-print Network

students taking level 3 English modules Theatre R, Newman Building 19.00 Movie Screening The Best Exotic students Theatre 1 Roebuck Castle 18.00 Orientation BBQ Food and refreshments served. 5 per person. UCD-EU exchange students' orientation (students outside of Business & Law)** Theatre N, Newman Building 16

264

TE/TM Simulations of Interferometric Measurements  

NASA Technical Reports Server (NTRS)

Interferometric synthetic aperture radar (IFSAR) measurements at X-, C-, L-, and P-band are used to derive ground topography at meter level resolution. Interpretation of the derived topography requires attention due to the complex interaction of the radar signal with ground cover. The presence of penetrable surfaces such as vegetation, and tree canopies poses a challenge since the depth of penetration depends on a number of parameters such as the operating radar frequency, polarization, incident angle, as well as terrain structure. The dependence of the reconstructed topography on polarization may lead to the characterization of the ground cover. Simulation of interferometric measurements is useful for interpretation of the derived topography (B. Houshmand, Proceedings of URSI, 314, 1997). In this talk , time domain simulations for interferometric measurement for TE- and TM- polarization are presented. Time domain simulation includes the effects of the surface material property as well geometry comparable the radar signal wavelength (B. Houshmand, Proceedings of the URSI, 25, 1998). The IFSAR simulation is carried out in two steps. First, the forward scattering data is generated based on full wave analysis. Next, the electromagnetic information is inverted to generate surface topography. This inversion is based on the well known IFSAR processing technique which is composed of signal compression, and formation of an interferogram. The full wave forward scattering data is generated by the scattered-field formulation of the FDTD algorithm. The simulation is carried out by exciting the computational domain by a radar signal. The scattered field is then computed and translated to the receiving interferometric antennas using the time-domain Huygen's principle. The inversion process starts by compressing the time-domain data. The range compressed data from both receivers are then coregistered to form an interferogram. The resulting interferogram is then related to the ground topography using the radar imaging geometry. In this talk, the simulation results are compared with the C-band TM IFSAR derived topography, and the TE/TM SAR images at L-Band.

Houshmand, Bijan

2000-01-01

265

Unconventional magnetism in multivalent charge-ordered YbPtGe2 probed by 195Pt- and 171Yb-NMR  

NASA Astrophysics Data System (ADS)

Detailed 195Pt and 171Yb nuclear magnetic resonance (NMR) studies on the heterogeneous mixed valence system YbPtGe2 are reported. The temperature dependence of the 195Pt-NMR shift 195K(T) indicates the opening of an unusual magnetic gap below 200 K. 195K(T) was analyzed by a thermal activation model which yields an isotropic gap ?/kB?200 K. In contrast, the spin-lattice relaxation rate 195(1/T1) does not provide evidence for the gap. Therefore, an intermediate-valence picture is proposed while a Kondo-insulator scenario can be excluded. Moreover, 195(1/T1) follows a simple metallic behavior, similar to the reference compound YPtGe2. A well-resolved NMR line with small shift is assigned to divalent 171Yb. This finding supports the proposed model with two subsets of Yb species (di- and trivalent) located on the Yb2 and Yb1 site of the YbPtGe2 lattice.

Sarkar, R.; Gumeniuk, R.; Leithe-Jasper, A.; Schnelle, W.; Grin, Y.; Geibel, C.; Baenitz, M.

2013-11-01

266

Magnetic-field-induced quantum critical point in YbPtIn and YbPt0.98In single crystals  

NASA Astrophysics Data System (ADS)

Detailed anisotropic ( H?ab and H?c ) resistivity and specific heat measurements were performed on on-line-grown YbPtIn and solution-grown YbPt0.98In single crystals for temperatures down to 0.4K and fields up to 140kG ; H?ab Hall resistivity was also measured on the YbPt0.98In system for the same temperature and field ranges. All these measurements indicate that the small change in stoichiometry between the two compounds drastically affects their ordering temperatures ( Tord?3.4K in YbPtIn and ˜2.2K in YbPt0.98In ). Furthermore, a field-induced quantum critical point is apparent in each of these heavy fermion systems, with the corresponding critical field values of YbPt0.98In ( Hcab around 35 45kG and Hcc?120kG ) also reduced compared to the analogous values for YbPtIn ( Hcab?60kG and Hcc>140kG ).

Morosan, E.; Bud'Ko, S. L.; Mozharivskyj, Y. A.; Canfield, P. C.

2006-05-01

267

Graphing Calculators, the CBL2[TM] and TI-Interactive[TM] in High School Science.  

ERIC Educational Resources Information Center

This collection of activities is designed to show how TI-Interactive[TM] and Calculator-based Laboratories (CBL) can be used to explore topics in high school science. The activities address such topics as specific heat, Boyle's Law, Newton's Law of Cooling, and Antarctic Ozone Levels. Teaching notes and calculator instructions are included as are…

Molnar, Bill

268

Mechanism of tantalum adhesion on SiLK{sup TM}  

SciTech Connect

Tantalum adhesion on SiLK{sup TM} was investigated using first-principles method based on density functional theory. Phenylene groups were found to play a major role and the adjacent semi-benzene rings also contribute significantly to Ta adhesion on SiLK{sup TM}. In addition, the degradation effects of H{sub 2}/He reactive plasma clean on Ta adhesion on SiLK{sup TM} was investigated. Based on our findings, argon plasma treatment was suggested and implemented after reactive plasma cleaning process, which resulted in integration of SiLK{sup TM} with Cu up to seven metal layers.

Hu Yue; Yang Shuowang; Chen Xiantong; Lu Dong; Feng Yuanping; Wu Ping [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Institute of High Performance Computing, 1 Science Park Road, Singapore 117528 (Singapore); Institute of Microelectronics, 11 Science Park Road, Singapore 117685 (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Institute of High Performance Computing, 1 Science Park Road, Singapore 117528 (Singapore)

2005-09-19

269

High-gain amplification in Yb:CaF2 crystals pumped by a high-brightness Yb-doped 976 nm fiber laser  

NASA Astrophysics Data System (ADS)

We report on high single-pass gain in Yb:CaF2 crystal longitudinally pumped with a 40 W high-brightness fiber laser source based on an ytterbium-doped ultra-large core photonic crystal rod-type fiber operating at 976 nm. A single-pass small-signal gain of 3.2 has been achieved in a 6 % Yb-doped 10-mm-long CaF2 crystal at room temperature, outperforming any CW-diode-pumped scheme and paving the way towards very promising innovative lasers and amplifiers schemes merging the Yb-doped solid-state and fiber technologies.

Machinet, G.; Andriukaitis, G.; Sévillano, P.; Lhermite, J.; Descamps, D.; Pugžlys, A.; Baltuška, A.; Cormier, E.

2013-05-01

270

Manganese-substituted rare-earth zinc arsenides RE(1-y)Mn(x)Zn(2-x)As2 (RE = Eu-Lu) and RE(2-y)Mn(x)Zn(4-x)As4 (RE = La-Nd, Sm, Gd).  

PubMed

Two series of Mn-substituted rare-earth zinc arsenides RE(1-y)Mn(x)Zn(2-x)As2 (RE = Eu-Lu) and RE(2-y)Mn(x)Zn(4-x)As4 (RE = La-Nd, Sm, Gd) were prepared by reaction of the elements at 750 °C. Both series are derived from ideal empirical formula REM2As2 (M = Mn, Zn) and adopt crystal structures related to the trigonal CaAl2Si2-type (space group P3m1) in which hexagonal nets of RE atoms and [M2As2] slabs built up of edge-sharing M-centered tetrahedra are alternately stacked along the c-direction. For compounds with divalent RE components (Eu, Yb), the fully stoichiometric and charge-balanced formula REM2As2 is obtained, with Mn and Zn atoms statistically disordered within the same tetrahedral site. For compounds with trivalent RE components, the RE sites become deficient, and the Mn atoms are segregated from the Zn atoms in separate tetrahedral sites. Within the series RE(1-y)Mn(x)Zn(2-x)As2 (Gd-Tm, Lu), the parent CaAl2Si2-type structure is retained, and the Mn atoms are disordered within partially occupied interstitial sites above and below [Zn(2-x)As2] slabs. Within the series RE(2-y)Mn(x)Zn(4-x)As4 (RE = La-Nd, Sm, Gd), the c-axis becomes doubled as a result of partial ordering of Mn atoms between every other pair of [Zn(2-x)As2] slabs. Attempts to synthesize Gd-containing solid solutions with the charge-balanced formula Gd0.67Mn(x)Zn(2-x)As2 suggested that these phases could be formed with up to 50% Mn substitution. Band structure calculations reveal that a hypothetical superstructure model with the formula La1.33MnZn3As4 would have no gap at the Fermi level and that slightly lowering the electron count alleviates antibonding Mn-As interactions; a spin-polarized calculation predicts nearly ferromagnetic half-metallic behavior. X-ray photoelectron spectroscopy confirms the presence of divalent Mn in these compounds. PMID:25062093

Lin, Xinsong; Tabassum, Danisa; Rudyk, Brent W; Mar, Arthur

2014-08-18

271

Effects of rare earth doping on the superconducting properties of MgB 2  

NASA Astrophysics Data System (ADS)

Doping effects of rare earth oxides (REO y: RE = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) on the superconducting properties of MgB 2 were investigated. Large fraction of the added RE turned into impurity phases: REB 6 for RE = La-Gd and Yb, and REB 4 for RE = Tb-Tm and Lu. We observed an increase in c-axis length from 3.523 to 3.533 Å when doped with Lu. Clear decreases in transition temperatures were observed in samples doped with Sm, Eu, Gd, Tm, Yb and Lu, indicating that these elements were successfully substituted for Mg. The decreases in Tc were most drastic in Yb-doped samples ( Tc ? 32 K).

Katsura, Y.; Shimoyama, J.; Yamamoto, A.; Horii, S.; Kishio, K.

2007-10-01

272

Photoluminescence properties and energy levels of RE (RE?=?Pr, Sm, Er, Tm) in layered-CaZnOS oxysulfide  

SciTech Connect

RE{sup 3+} (RE?=?Pr, Sm, Er, Tm)-activated CaZnOS samples were prepared by a solid-state reaction method at high temperature, and their photoluminescence properties were investigated. Doping with RE{sup 3+} (RE?=?Pr, Sm, Er, Tm) into layered-CaZnOS resulted in typical RE{sup 3+} (RE?=?Pr, Sm, Er, Tm) f-f line absorptions and emissions, as well as the charge transfer band of Sm{sup 3+} at about 3.3?eV. The energy level scheme containing the position of the 4f and 5d levels of all divalent and trivalent lanthanide ions with respect to the valence and conduction bands of CaZnOS has been constructed based on the new data presented in this work, together with the data from literature on Ce{sup 3+} and Eu{sup 2+} doping in CaZnOS. The detailed energy level scheme provides a platform for interpreting the optical spectra and could be used to comment on the valence stability of the lanthanide ions in CaZnOS.

Zhang, Zhi-Jun, E-mail: zhangzj@mail.sic.ac.cn [Key Laboratory of Transparent Opto-Functional Inorganic Materials of Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai 200050 (China); Feng, Ang; Chen, Xiang-Yang [Key Laboratory of Transparent Opto-Functional Inorganic Materials of Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Zhao, Jing-Tai, E-mail: jtzhao@mail.sic.ac.cn [Key Laboratory of Transparent Opto-Functional Inorganic Materials of Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai 200050 (China); School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)

2013-12-07

273

Near-IR Photoresponse in New Up-Converting CdSe/NaYF4:Yb,Er Nanoheterostructures  

E-print Network

Near-IR Photoresponse in New Up-Converting CdSe/NaYF4:Yb,Er Nanoheterostructures Chenglin Yan-converting nanocrystals is NaYF4: Yb,Er, in which Yb dopant ions absorb NIR photons and the Er ions emit the up from NaYF4:Yb,Er to CdSe QDs has recently been shown for a core-shell structure.10a However, using

274

Identification of parasitic losses in Yb:YLF and prospects for optical refrigeration down to 80K.  

PubMed

Systematic study of Yb doping concentration in the Yb:YLF cryocoolers by means of optical and mass spectroscopies has identified iron ions as the main source of the background absorption. Parasitic absorption was observed to decrease with Yb doping, resulting in optical cooling of a 10% Yb:YLF sample to 114K ± 1K, with room temperature cooling power of 750 mW and calculated minimum achievable temperature of 93 K. PMID:24718151

Melgaard, Seth; Seletskiy, Denis; Polyak, Victor; Asmerom, Yemane; Sheik-Bahae, Mansoor

2014-04-01

275

Quantitative analysis of Eu 2+ and Eu 3+ in LiCl-KCl eutectic melt by spectrophotometry and electrochemistry  

NASA Astrophysics Data System (ADS)

The redox behavior of Eu 2+ and Eu 3+ in the LiCl-KCl eutectic at 773 K was investigated. Since the equilibrium potential of the melt is very close to the redox potential of the Eu 3+|Eu 2+ couple, the Eu 2+ and Eu 3+ species coexist. Quantitative analysis of Eu 2+ and Eu 3+ was performed by spectrophotometry and by potentiometry. Under the coexistence of Eu 2+ and Eu 3+, potentiometric titration of Eu ion using a yttria-stabilized zirconia membrane electrode (YSZME) was performed by changing the concentration of O 2-. The formation of the europium oxychloride, EuOCl, was confirmed by X-ray diffraction analysis, whiles no precipitation of the oxides, EuO and Eu 2O 3, was found. The equivalent point of the EuOCl formation ( x = [O 2-] added/[Eu] total) was shifted to a smaller value from the theoretical value ( x = 1) due to the coexisting Eu 2+. The contribution of the coexisting Eu 2+ to the formation of EuOCl was estimated by using [Eu 2+]/[Eu 3+] as determined by potentiometry and this was subtracted from the titration data. The solubility product of EuOCl was determined to be p ks(EuOCl) = 7.81 ± 0.10.

Kim, Tack-Jin; Uehara, Akihiro; Nagai, Takayuki; Fujii, Toshiyuki; Yamana, Hajimu

2011-02-01

276

The feed-forward loop between YB-1 and MYC is essential for multiple myeloma cell survival  

PubMed Central

Y-box binding protein 1 (YB-1) functions as a translational regulator and has been suggested to elevate MYC mRNA translation via an internal ribosome entry segment (IRES) point mutation in multiple myeloma (MM). We show that YB-1-mediated translation of MYC mRNA occurs independently of the reported IRES mutation, as 87 MM patients (n = 88) and all tested human MM cell lines (HMCLs) were negative for the mutation. We show for the first time that positive MYC staining predicts YB-1 co-expression in malignant plasma cells and YB-1/MYC co-expression increases from 30% in medullary to 70% in extramedullary MM. YB-1 knockdown in HMCLs reduced both MYC protein levels and MYC mRNA in the polysomal fraction, providing a mechanism by which YB-1 controls MYC translation. MYC transcription of YB-1 is demonstrated in HMCLs as MYC knockdown resulted in reduced YB-1 protein and mRNA levels. Furthermore, MYC activation in non-malignant mouse embryonic fibroblasts (MEFs) increased YB-1 mRNA, clearly indicating that MYC drives YB-1 transcription. Importantly, perturbation of the MYC/YB-1 oncogenic circuit leads to apoptosis in HMCLs. Here, we demonstrate that these two proteins co-regulate each other via combined transcriptional/translational activity establishing their pivotal role in MM cell survival. We therefore suggest that targeting the YB-1/mRNA interaction provides a new strategy for MM drug development. PMID:22772059

Bommert, KS; Effenberger, M; Leich, E; Kuspert, M; Murphy, D; Langer, C; Moll, R; Janz, S; Mottok, A; Weissbach, S; Rosenwald, A; Bargou, R; Bommert, K

2014-01-01

277

One-Dimensional Optical Lattice Clock with a Fermionic 171Yb Isotope  

NASA Astrophysics Data System (ADS)

We demonstrate a one-dimensional optical lattice clock with ultracold 171Yb atoms, which is free from the linear Zeeman effect. The absolute frequency of the 1S0(F = 1/2)-3P0(F = 1/2) clock transition in 171Yb is determined to be 518 295 836 590 864(28) Hz with respect to the SI second.

Kohno, Takuya; Yasuda, Masami; Hosaka, Kazumoto; Inaba, Hajime; Nakajima, Yoshiaki; Hong, Feng-Lei

2009-07-01

278

Relativistic effects in E1 transition oscillator strengths along the Yb+ isoelectronic sequence  

NASA Astrophysics Data System (ADS)

Electric dipole transition oscillator strengths have been computed for low-lying transitions in the Yb+ isoelectronic sequence (through Ra19 +) in fully relativistic and non-relativistic-limit approximations. Relativistic effects were carefully investigated and efforts were undertaken to establish systematic trends in relativistic contributions to oscillator strengths along the Yb+ isoelectronic sequence.

Migdalek, J.; Siegel, W.

2014-04-01

279

250 W single-crystal fiber Yb:YAG laser Xavier Dlen,1,  

E-print Network

-crystal fiber oscillator pumped at 600 W with a fiber coupled laser diode at 940 nm. Furthermore, we discuss250 W single-crystal fiber Yb:YAG laser Xavier Délen,1, * Stefan Piehler,2 Julien Didierjean,3 demonstrate an Yb:YAG single-crystal fiber laser with 251 W output power in continuous-wave and an optical

Paris-Sud XI, Université de

280

Yb:CaGdAlO4 laser under high pumping power: high performances and singularities  

NASA Astrophysics Data System (ADS)

We present some anisotropy properties of the Yb:CALGO with a spatial mode switching when pumped in the multihundred watts of power. This allows to automatically stabilize a TEM00 mode from highly spatial-multimode regime. This stabilization is achievable thanks to a polarization mode switching allowed by the particular anisotropic spectroscopy and thermal properties of Yb:CALGO.

Druon, F.; Olivier, M.; Balembois, F.; Georges, P.; Aubry, N.; DidierJean, J.; Jaffrès, A.; Loiseau, P.; Viana, B.

2014-02-01

281

Modeling of quasi-three-level lasers and operation of cw Yb:YAG lasers  

E-print Network

Modeling of quasi-three-level lasers and operation of cw Yb:YAG lasers Takunori Taira, William M. Tulloch, and Robert L. Byer We present modeling studies of quasi-three-level laser oscillators, the validity of which was revealed by Ti:Al2O3-pumped Yb:YAG laser experiments, and these results are shown

Byer, Robert L.

282

Synthesis and Thermoelectric Properties of Yb-doped Ca0.9-x Yb x La0.1MnO3 Ceramics  

NASA Astrophysics Data System (ADS)

The microstructure and thermoelectric properties of Yb-doped Ca0.9-x Yb x La0.1 MnO3 (0 ? x ? 0.05) ceramics prepared by using the Pechini method derived powders have been investigated. X-ray diffraction analysis has shown that all samples exhibit single phase with orthorhombic perovskite structure. All ceramic samples possess high relative densities, ranging from 97.04% to 98.65%. The Seebeck coefficient is negative, indicating n-type conduction in all samples. The substitution of Yb for Ca leads to a marked decrease in the electrical resistivity, along with a moderate decrease in the absolute value of the Seebeck coefficient. The highest power factor is obtained for the sample with x = 0.05. The electrical conduction in these compounds is due to electrons hopping between Mn3+ and Mn4+, which is enhanced by increasing Yb content.

Zhang, Bo; Chang, Aimin; Zhao, Qing; Ye, Haitao; Wu, Yiquan

2014-08-01

283

Full Immersive Virtual Environment Cave[TM] in Chemistry Education  

ERIC Educational Resources Information Center

By comparing two-dimensional (2D) chemical animations designed for computer's desktop with three-dimensional (3D) chemical animations designed for the full immersive virtual reality environment CAVE[TM] we studied how virtual reality environments could raise student's interest and motivation for learning. By using the 3ds max[TM], we can visualize…

Limniou, M.; Roberts, D.; Papadopoulos, N.

2008-01-01

284

Estimation of forest parameters through fuzzy classification of TM data  

Microsoft Academic Search

Several studies have investigated the utility of Landsat 5 TM imagery to estimate forest parameters such as stand composition and density. Regression equations have generally been used to relate these parameters to the radiance responses of the TM channels. Such a method is not feasible in highly complex landscapes, where forest mixtures and terrain irregularities may obscure the existence of

Fabio Maselli; Claudio Conese; Tiziana De Filippis; Stefano Norcini

1995-01-01

285

Relative radiometric calibration of LANDSAT TM reflective bands  

NASA Technical Reports Server (NTRS)

A common scientific methodology and terminology is outlined for characterizing the radiometry of both TM sensors. The magnitude of the most significant sources of radiometric variability are discussed and methods are recommended for achieving the exceptional potential inherent in the radiometric precision and accuracy of the TM sensors.

Barker, J. L.

1984-01-01

286

Kilo TM Correctness: ABA Tolerance and Validation-Commit Indivisibility  

E-print Network

Kilo TM Correctness: ABA Tolerance and Validation-Commit Indivisibility Wilson W. L. Fung to improve commit parallelism). More details regarding the design of Kilo TM are available in our paper for the correctness of value-based conflict detection is the possibility of subtle bugs due to the ABA problem. We

Aamodt, Tor

287

Doors to Discovery[TM]. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

"Doors to Discovery"[TM] is an early childhood curriculum that uses thematic units to engage young children and support them as they build an understanding of their world. "Doors to Discovery"[TM] literacy activities are used to encourage children's development in a number of areas identified by research as the foundation for early literacy…

What Works Clearinghouse, 2007

2007-01-01

288

ORNL/TM-2007/224 BIOFUEL FEEDSTOCK ASSESSMENT FOR  

E-print Network

ORNL/TM-2007/224 BIOFUEL FEEDSTOCK ASSESSMENT FOR SELECTED COUNTRIES Keith L. Kline Gbadebo A Government or any agency thereof. #12;ORNL/TM-2007/224 BIOFUEL FEEDSTOCK ASSESSMENT FOR SELECTED COUNTRIES To Support the DOE study of Worldwide Potential to Produce Biofuels with a focus on U.S. Imports Keith L

Pennycook, Steve

289

Inside Linden Lab: Second Life [TM] for Educators  

ERIC Educational Resources Information Center

A new culture called Second Life [TM] has emerged that promises innovative strategies for everything from social interactions to business. Some educators believe it may hold new and unique opportunities for teaching and learning. Second Life [TM] (SL) is the creation of Linden Labs, a San Francisco-based corporation defined by its creators as "an…

Atkinson, Tom

2008-01-01

290

Social Stories[TM] for Children with Disabilities  

ERIC Educational Resources Information Center

A review of the empirical research literature on Social Stories[TM] is presented, including a descriptive review and single-subject meta-analysis of appropriate studies. Examination of data suggests the effects of Social Stories[TM] are highly variable. Interpretations of extant studies are frequently confounded by inadequate participant…

Reynhout, Georgina; Carter, Mark

2006-01-01

291

SpellRead[TM]. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

"SpellRead"[TM], formerly known as "SpellRead Phonological Auditory Training"[R], is a small-group literacy program for struggling readers in grades 2-12. "SpellRead"[TM] integrates the auditory and visual aspects of the reading process and emphasizes specific skill mastery through systematic and explicit instruction. Students are taught to…

What Works Clearinghouse, 2013

2013-01-01

292

Accelerated Math[TM]. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

"Accelerated Math"[TM], published by Renaissance Learning, is a software tool used to customize assignments and monitor progress in mathematics for students in grades 1-12. "Accelerated Math"[TM] creates individualized assignments that align with state standards and national guidelines, scores student work, and generates formative feedback through…

What Works Clearinghouse, 2010

2010-01-01

293

Social Stories[TM]: A Possible Theoretical Rationale  

ERIC Educational Resources Information Center

Social Stories[TM] are an intervention widely used with individuals with autism spectrum disorders (ASD). This paper discusses a possible theoretical rationale that might account for the purported efficacy of Social Stories[TM]. Attributes of individuals with ASD in relation to Social Story intervention including difficulties with theory of mind…

Reynhout, Georgina; Carter, Mark

2011-01-01

294

Accelerated Reader[TM]. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

"Accelerated Reader"[TM] is a guided reading intervention used to supplement regular reading instruction in K-12 classrooms. Its aim is to improve students' reading skills through reading practice and quizzes on the books students read. The "Accelerated Reader"[TM] program calls for students to select and read a book and then take a computerized…

What Works Clearinghouse, 2010

2010-01-01

295

SUMOstarTM Insect Cell Expression and Purification Systems  

E-print Network

@lifesensors.com 610.644.8845 (phone) 610.644.8616 (fax) #12;SUMOstarTM Insect Cell Expression Systems ©2007 LifeSUMOstarTM Insect Cell Expression and Purification Systems Catalogue #3100 (Intracellular Kit) 3101 Valley Parkway Malvern, PA 19355 www.lifesensors.com techsupport@lifesensors.com sales

Lebendiker, Mario

296

ORNL/TM-2005/230 POWER ELECTRONICS FOR  

E-print Network

ORNL/TM-2005/230 POWER ELECTRONICS FOR DISTRIBUTED ENERGY SYSTEMS AND TRANSMISSION AND DISTRIBUTION of Tennessee-Knoxville #12;ORNL/TM-2005/230 Engineering Science and Technology Division POWER ELECTRONICS.............................................................................. ......... 1-1 1.1 What is Power Electronics

Tolbert, Leon M.

297

Accelerated Math[TM]. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

"Accelerated Math"[TM], published by Renaissance Learning, is a software tool used to customize assignments and monitor progress in math for students in grades 1-12. The "Accelerated Math"[TM] software creates individualized assignments aligned with state standards and national guidelines, scores student work, and generates reports on student…

What Works Clearinghouse, 2011

2011-01-01

298

Using KinectTM and a Haptic Interface for  

E-print Network

Using KinectTM and a Haptic Interface for Implementation of Real-Time Virtual Fixtures Fredrik Ryd fixtures using a low cost Xbox KinectTM depth camera connected to a virtual environment. This allows Kinect, a low cost device developed for the gaming purposes. In Section II depth cameras and RGB

299

ISI TechnicalManual ISI/TM-88-197  

E-print Network

ISI TechnicalManual ISI/TM-88-197 February1988 University ofSouthern California Gabriel Robins %% ... ... .. The ISI Grapher Manual INFORMATION SCIENCES 213/822-1511 INSTITUTEJ f-"-676 292-t5466Admiralty Way. MONITORING ORGANIZATION REPORT NUMBER(S) ISI/TM-88-197 6a. NAME OF PERFORMING ORGANIZATION USC

Robins, Gabriel

300

Clock-transition spectrum of 171Yb atoms in a one-dimensional optical lattice  

NASA Astrophysics Data System (ADS)

An optical atomic clock with 171Yb atoms is devised and tested. By using a two-stage Doppler cooling technique, the 171Yb atoms are cooled down to a temperature of 6±3 ?K, which is close to the Doppler limit. Then, the cold 171Yb atoms are loaded into a one-dimensional optical lattice with a wavelength of 759 nm in the Lamb—Dicke regime. Furthermore, these cold 171Yb atoms are excited from the ground-state 1S0 to the excited-state 3P0 by a clock laser with a wavelength of 578 nm. Finally, the 1S0-3P0 clock-transition spectrum of these 171Yb atoms is obtained by measuring the dependence of the population of the ground-state 1S0 upon the clock-laser detuning.

Chen, Ning; Zhou, Min; Chen, Hai-Qin; Fang, Su; Huang, Liang-Yu; Zhang, Xiao-Hang; Gao, Qi; Jiang, Yan-Yi; Bi, Zhi-Yi; Ma, Long-Sheng; Xu, Xin-Ye

2013-09-01

301

Registratiom of TM data to digital elevation models  

NASA Technical Reports Server (NTRS)

Several problems arise when attempting to register LANDSAT thematic mapper data to U.S. B Geological Survey digital elevation models (DEMs). The TM data are currently available only in a rotated variant of the Space Oblique Mercator (SOM) map projection. Geometric transforms are thus; required to access TM data in the geodetic coordinates used by the DEMs. Due to positional errors in the TM data, these transforms require some sort of external control. The spatial resolution of TM data exceeds that of the most commonly DEM data. Oversampling DEM data to TM resolution introduces systematic noise. Common terrain processing algorithms (e.g., close computation) compound this problem by acting as high-pass filters.

1984-01-01

302

Interfacial effects in Fe/4d TM multilayers (abstract)  

SciTech Connect

We have studied Fe/TM multilayers (TM=Mo, Nb, Ru, Rh, Pd) using x-ray magnetic circular dischroism, magneto-optical Kerr effect, and x-ray diffraction. A diverse set of magnetic behaviors emerges from the analysis. We focus on the behavior which can be attributed to the existence of a physical interface between different chemical species. In particular, we have measured an enhanced Fe moment in some cases (TM=Ru, Mo, Rh, Pd) yet not in others (TM=Nb). These results will be discussed, including the relative orbital and spin moments and the effects of alloying at the interface. The measured induced moments in the TM layer will be presented as well where applicable. {copyright} {ital 1997 American Institute of Physics.}

Tomaz, M.A.; Antel, W.J., Jr.; Harp, G.R. [Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701 (United States)] [Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701 (United States); OBrien, W.L. [Synchrotron Radiation Center, University of Wisconsin, Stoughton, Wisconsin 53589 (United States)] [Synchrotron Radiation Center, University of Wisconsin, Stoughton, Wisconsin 53589 (United States)

1997-04-01

303

Bright white light through up-conversion of a single NIR source from sol-gel-derived thin film made with Ln3+-doped LaF3 nanoparticles.  

PubMed

White light was generated from a single silica thin film made with Yb0.75La0.2Eu0.05F3, La0.45Yb0.5Er0.05F3, and La0.75Yb0.2Tm0.05F3 nanoparticles by exciting with a single source near-infrared light (980 nm CW diode laser). Eu3+ and Tm3+ ions are responsible for red and blue emission, respectively. Er3+ ion is responsible for green as well as red emission. The Commission Internationale de l'Eclairage (CIE) coordinates of the resulting light were easily adjusted by controlling the concentration of Ln3+ (Eu3+, Er3+, Tm3+) ions in the nanoparticles as well as the concentration of Ln3+-doped nanoparticles in the sol-gel thin layer. PMID:16144374

Sivakumar, Sri; van Veggel, Frank C J M; Raudsepp, Mati

2005-09-14

304

Water quality mapping using Landsat TM imagery  

NASA Astrophysics Data System (ADS)

Environmental monitoring through the method of traditional ship sampling is time consuming and requires a high survey cost. The objective of this study is to evaluate the feasibility of Landsat TM imagery for total suspended solids (TSS) mapping using a newly developed algorithm over Penang Island. The study area is the seawater region around Penang Island, Malaysia. Water samples were collected during a 3-hour period simultaneously with the satellite image acquisition and later analyzed in the laboratory above the study area. The samples locations were determined using a handheld GPS. The satellite image was geometrically corrected using the second order polynomial transformation. The satellite image also was atmospheric corrected by using ATCOR2 image processing software. The digital numbers for each band corresponding to the sea-truth locations were extracted and then converted into reflectance values for calibration of the water quality algorithm. The proposed algorithm is based on the reflectance model that is a function of the inherent optical properties of water, which can be related to its constituent's concentrations. The generated algorithm was developed for three visible wavelenghts, red, green and blue for this study. Results indicate that the proposed developed algorithm was superior based on the correlation coefficient (R) and root-mean-square deviation (RMS) values. Finally the proposed algorithm was used for TSS mapping at Penang Island, Malaysia. The generated TSS map was colour-coded for visual interpretation and image smoothing was performed on the map to remove random noise. This preliminary study has produced a promising result. This study indicates that the empirical algorithm is suitable for TSS mapping around Penang Island by using satellite Landsat TM data.

Lim, H. S.; MatJafri, M. Z.; Abdullah, K.; Alias, A. N.; Wong, C. J.; Mustapha-Rosli, M. R.; Mohd Saleh, N.

2009-05-01

305

Reduced Probabilities of E2-Transitions in {sup 174}Yb  

SciTech Connect

This paper describes the ground (gr) and exited states of even-even deformed nuclei with a phenomenological model, which takes into account the mixing of gr states, 0{sub n}{sup +}({beta}{sub n})-, 2{sub n}{sup +}({gamma}{sub n})- and {Kappa}{sup {pi}} 1{sub n}{sup +}- rotational bands. The calculation has been done for the isotope Yb. The energy spectra are found to be consistent with the energies from experimental data. The reduced probabilities of the electric quadrupole E2-transitions from {beta}{sub n} and {gamma}{sub n} band states are calculated and agree quite well with the experimental values.

Okhunov, A. A. [Quantum Science Center Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Institute for Nuclear Physics, Academy Science of Uzbekistan, 100214 Tashkent (Uzbekistan); Kassim, Hasan Abu [Quantum Science Center Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-03-30

306

Atomic Mass and Nuclear Binding Energy for Yb-171 (Ytterbium)  

NASA Astrophysics Data System (ADS)

This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Yb-171 (Ytterbium, atomic number Z = 70, mass number A = 171).

Sukhoruchkin, S. I.; Soroko, Z. N.

307

Atomic Mass and Nuclear Binding Energy for Yb-227 (Ytterbium)  

NASA Astrophysics Data System (ADS)

This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Yb-227 (Ytterbium, atomic number Z = 70, mass number A = 227).

Sukhoruchkin, S. I.; Soroko, Z. N.

308

Output spectrum of Yb-doped fiber lasers.  

PubMed

An analytical model for self phase modulation in Yb-doped fiber laser (YDFL) describing output spectrum and its broadening with increasing power has been developed. Spectral measurements in continuous wave (CW) cladding-pumped YDFL have proved the validity of the model demonstrating hyperbolic secant shape of the spectrum and linear increase of the line width with power in 1-12 W range. At lower powers, spatial hole burning and line self-sweeping effects become important and define the lower limit for the line width. PMID:22743437

Kablukov, S I; Zlobina, E A; Podivilov, E V; Babin, S A

2012-07-01

309

Wi-FiTM (802.11b) and BluetoothTM: An Examination of Coexistence Approaches  

E-print Network

analyzes different approaches to resolving the interference problems between the Wi-Fi TM and Bluetooth TM without this understanding read Mobilian's first white paper: Wi-Fi (802.11b) and Bluetooth Simultaneous............................................................................................................................................9 3.2 Driver-level (Modal) Switching Between Wi-Fi and Bluetooth

Han, Richard Y.

310

Ultrafast Transparent Ceramic Scintillators Using the Yb3+ Charge Transfer Luminescence in RE2O3 Host  

NASA Astrophysics Data System (ADS)

We report a new discovery of Yb3+-doped ultrafast scintillators based on the Yb3+ charge transfer luminescence. Transparent ceramic Yb3+-doped Y2O3, Sc2O3, Lu2O3, and Yb2O3 were prepared by sintering. When irradiated by ?- and X-rays, they showed a well detectable photoabsorption peak in the pulse height spectra and ultrafast scintillation decay dominated by the decay time of about 1 ns. For the first time, the Yb3+-doped oxide materials show detectable scintillation in the pulse height measurement at room temperature with ultrafast scintillation decay.

Yanagida, Takayuki; Fujimoto, Yutaka; Kurosawa, Shunsuke; Watanabe, Kenichi; Yagi, Hideki; Yanagitani, Takagimi; Jary, Vitezslav; Futami, Yoshisuke; Yokota, Yuui; Yoshikawa, Akira; Uritani, Akira; Iguchi, Tetsuo; Nikl, Martin

2011-12-01

311

Internet: http://ue.eu.int/Newsroom E-mail: press.office@consilium.eu.int  

E-print Network

.............................................IV - Africa ­ human rightsInternet: http://ue.eu.int/Newsroom E-mail: press.office@consilium.eu.int 15078/01 (Presse 460 - G ......................................................................................21 ITEMS APPROVED WITHOUT DEBATE ENLARGEMENT - Accession partnerships

Sussex, University of

312

LaVo4: Eu Phosphor Films with Enhanced Eu Solubility  

SciTech Connect

Eu doped rare-earth orthovanadates are known to be good red phosphor materials. In particular, LaVO{sub 4}:Eu is a promising candidate due to the low Eu-site point symmetry, and thus high dipole transition probability within Judd-Ofelt theory. However, the low solubility limit (< 3 mol %) of Eu in LaVO{sub 4} prevents its efficient use as a phosphor. We present optical evidence of enhanced Eu solubility as high as 10 mol % in LaVO{sub 4}:Eu thin films grown by pulsed laser deposition and postannealing. The photoluminescent intensity exceeded that of YVO{sub 4}:Eu thin films when excited below the host bandgap, indicating stronger direct emission of Eu in LaVO{sub 4}.

Hwang, Harold

2011-08-11

313

LaVO4:Eu Phosphor films with enhanced Eu solubility  

NASA Astrophysics Data System (ADS)

Eu doped rare-earth orthovanadates are known to be good red phosphor materials. In particular, LaVO4:Eu is a promising candidate due to the low Eu-site point symmetry, and thus high dipole transition probability within Judd-Ofelt theory. However, the low solubility limit (<3 mol %) of Eu in LaVO4 prevents its efficient use as a phosphor. We present optical evidence of enhanced Eu solubility as high as 10 mol % in LaVO4:Eu thin films grown by pulsed laser deposition and postannealing. The photoluminescent intensity exceeded that of YVO4:Eu thin films when excited below the host bandgap, indicating stronger direct emission of Eu in LaVO4.

Higuchi, T.; Hotta, Y.; Hikita, Y.; Maruyama, S.; Hayamizu, Y.; Akiyama, H.; Wadati, H.; Hawthorn, D. G.; Regier, T. Z.; Blyth, R. I. R.; Sawatzky, G. A.; Hwang, H. Y.

2011-02-01

314

Internet: http://ue.eu.int/Newsroom E-mail: press.office@consilium.eu.int  

E-print Network

Internet: http://ue.eu.int/Newsroom E-mail: press.office@consilium.eu.int PRE 052/04 (Presse) EN of the laws of the Member States concerning the safety of toys = Political agreement - Public deliberation

315

Tertium Datur: Turkey's Application for EU Membership  

Microsoft Academic Search

In place of an ‘in or out’ dichotomy, a third way must be offered between European Union (EU) membership and the European\\u000a Neighbourhood Policy, consisting of a diversification of the forms of cooperation and integration between the EU and its neighbouring\\u000a countries. The question as to Turkey’s accession capability and the EU’s enlargement capacity affects the identity of both\\u000a sides.

Thomas Silberhorn

316

Contribution of Eu 4f states to the magnetic anisotropy of EuO  

SciTech Connect

Anisotropic x-ray magnetic linear dichroism (AXMLD) provides a novel element-, site-, shell-, and symmetry-selective techniques to study the magnetic anisotropy induced by a crystalline electric field. The weak Eu2+ M4,5 AXMLD observed in EuO(001) indicates that the Eu 4f states are not rotationally invariant and hence contribute weakly to the magnetic anisotropy of EuO. The results are contrasted with those obtained for 3d transition metal oxides.

Arenholz, E.; Schmehl, A.; Schlom, D.G.; van der Laan, G.

2008-09-11

317

Internet: http://ue.eu.int E-mail: press.office@consilium.eu.int  

E-print Network

Internet: http://ue.eu.int E-mail: press.office@consilium.eu.int For further information call 32 2 references are given in the text are available on the Council's Internet site http://ue.eu.int. Acts adopted; these statements are available on the above mentioned Council Internet site or may be obtained from the Press

318

EU Dairy Sector: Impact of Luxemburg Reform, EU Enlargement and Trade Negotiations  

Microsoft Academic Search

The EU dairy sector is facing a period of significant changes that are due to three major decisions: the EU enlargement, the Luxembourg reform and on-going WTO negotiations. To evaluate the impact of such changes we developed a model of the EU and world dairy industry. The model is composed of two modules that interact: a milk and beef supply

Zohra Bouamra-Mechemache; Hela Hadj Ali-Kein; Roelof A. Jongeneel; Axel Tonini; Vincent Requillart

2005-01-01

319

EU Dairy sector : impact of Luxemburg reform, EU enlargement and trade negotiations  

Microsoft Academic Search

The EU dairy sector is facing a period of significant changes that are due to three major decisions : the EU enlargement, le Luxembourg reform and on-going WTO negotiations. To evaluate the impact of such changes we developed a model of the EU and world dairy industry. The model is composed of two modules that interact : a milk and

Z. Bouamra-Mechemache; H. Hadj-Ali Kein; R. Jongeneel; A. Réquillart V. Tonini

2005-01-01

320

Insights into the energy transfer mechanism in Ce3+-Yb3+ codoped YAG phosphors  

NASA Astrophysics Data System (ADS)

Two distinct energy transfer (ET) mechanisms have been proposed for the conversion of blue to near-infrared (NIR) photons in YAG:Ce3+,Yb3+. The first mechanism involves downconversion by cooperative energy transfer, which would yield two NIR photons for each blue photon excitation. The second mechanism of single-step energy transfer yields only a single NIR photon for each blue photon excitation and has been argued to proceed via a Ce4+-Yb2+ charge transfer state (CTS). If the first mechanism were operative in YAG:Ce3+,Yb3+, this material would have the potential to greatly increase the response of crystalline Si solar cells to the blue/UV part of the solar spectrum. In this work, however, we demonstrate that blue-to-NIR conversion in YAG:Ce3+,Yb3+ goes via the single-step mechanism of ET via a Ce4+-Yb2+ CTS. The photoluminescence decay dynamics of the Ce3+ excited state are inconsistent with Monte Carlo simulations of the cooperative (one-to-two photon) energy transfer, while they are well reproduced by simulations of single-step (one-to-one photon) energy transfer via a charge transfer state. Based on temperature dependent measurements of energy transfer and luminescence quenching we construct a configuration coordinate model for the Ce3+-to-Yb3+ energy transfer, which includes the Ce4+-Yb2+ charge transfer state.

Yu, D. C.; Rabouw, F. T.; Boon, W. Q.; Kieboom, T.; Ye, S.; Zhang, Q. Y.; Meijerink, A.

2014-10-01

321

Optical and scintillation properties of SrI2:Yb2+  

NASA Astrophysics Data System (ADS)

The luminescence and scintillation properties of SrI2:0.5%Yb2+ have been investigated. SrI2:Yb single crystals were grown by the vertical Bridgeman method from the melt. They showed a light yield of 38,400 ph/MeV and energy resolution of 12.5% for the 662 keV full absorption peak. Yb2+ photoluminescence intensity and decay time were studied between 78 and 600 K. Two emission bands centered at 418 and 446 nm were observed and ascribed to spin-allowed and spin-forbidden Yb2+ 5d-4f transitions, respectively. Their corresponding room-temperature decay time constants are 710 ns and 77 ?s. Both, the emission intensities and the decay time constants vary with temperature. The obtained results were interpreted using a model of self-absorption of Yb2+ emission and a model of non-radiative relaxation of the electron from the low spin to the high spin 4f135d Yb2+ excited states. The radiative lifetime of the low spin Yb2+ excited state was determined as 400 ns.

Alekhin, Mikhail S.; Biner, Daniel A.; Krämer, Karl W.; Dorenbos, Pieter

2014-11-01

322

Yb-substituted clathrates Ba8-xYbxGa16Ge30  

NASA Astrophysics Data System (ADS)

Exploration of new rare-earth captured clathrates is an important field of clathrate application. Study on the second phases produced in the synthesis process is crucial for confirming the incorporation of rare earth atoms into the clathrate lattice. In the current study, the Yb-doped clathrate samples with nominal composition of Ba6Yb2Ga16Ge30 were prepared by combining arc melting (ARC), melt spinning (MS) and spark plasma sintering (SPS) techniques. By using the TEM with EDS analysis and X-ray diffraction refinement, phase analysis was systemically performed in different steps of the preparation process. Although the clathrate was the main phase in obtained samples, the Yb content in the clathrate phase was found to be much lower than the nominal composition as the Yb atoms strongly tend to create other byproduct phases including Yb2O3 — which is the main obstacle in the synthesis of Yb-substituted clathrates. For the dilute Yb-doped germanium clathrate sample a decrease in the thermal conductivity and electrical conductivity was simultaneously observed, therefore, no expected improvement of ZT occurred.

Liu, L. H.; Wei, Y. P.; Yang, S. W.; Zhu, J.; Li, Y.

2014-06-01

323

Stimulated Raman adiabatic passage in Tm{sup 3+}:YAG  

SciTech Connect

We report on the experimental demonstration of stimulated Raman adiabatic passage in a Tm{sup 3+}:YAG crystal. Tm{sup 3+}:YAG is a promising material for use in quantum information processing applications, but as yet there are few experimental investigations of coherent Raman processes in this material. We investigate the effect of inhomogeneous broadening and Rabi frequency on the transfer efficiency and the width of the two-photon spectrum. Simulations of the complete Tm{sup 3+}:YAG system are presented along with the corresponding experimental results.

Alexander, A. L.; Lauro, R.; Louchet, A.; Chaneliere, T.; Le Goueet, J. L. [Laboratoire Aime Cotton, CNRS-UPR 3321, University Paris-Sud, Bat. 505, 91405 Orsay Cedex (France)

2008-10-01

324

Review of Tm and Ho Materials; Spectroscopy and Lasers  

NASA Technical Reports Server (NTRS)

A review of Tm and Ho materials is presented, covering some fundamental aspects on the spectroscopy and laser dynamics in both single and co-doped systems. Following an introduction to 2- m lasers, applications and historical development, the physics of quasi-four level lasers, energy transfer and modeling are discussed in some detail. Recent developments in using Tm lasers to pump Ho lasers are discussed, and seen to offer some advantages over conventional Tm:Ho lasers. This article is not intended as a complete review, but as a primer for introducing concepts and a resource for further study.

Walsh, Brian M.

2008-01-01

325

Tm:germanate Fiber Laser: Tuning And Q-switching  

NASA Technical Reports Server (NTRS)

A Tm:germanate fiber laser produced >0.25 mJ/pulse in a 45 ns pulse. It is capable of producing multiple Q-switched pulses from a single p ump pulse. With the addition of a diffraction grating, Tm:germanate f iber lasers produced a wide, but length dependent, tuning range. By s electing the fiber length, the tuning range extends from 1.88 to 2.04 ?m. These traits make Tm:germanate lasers suitable for remote sensin g of water vapor.

Barnes, Norman P.; Walsh, Brian M.; Reichle, Donald J.; DeYoung, R. J.; Jiang, Shibin

2007-01-01

326

Formation, optical properties, and electronic structure of thin Yb silicide films on Si(111)  

NASA Astrophysics Data System (ADS)

Continuous very thin (2.5-3.0 nm) and thin (16-18 nm) ytterbium suicide films with some pinhole density (3×107- 1×108 cm-2) have been formed on Si(111) by solid phase epitaxy (SPE) and reactive deposition epitaxy (RDE) growth methods on templates. The stoichiometric ytterbium suicide (YbSi2) formation has shown in SPE grown films by AES and EELS data. Very thin Yb suicide films grown by RDE method had the silicon enrichment in YbSi2 suicide composition. The analysis of LEED data and AFM imaging has shown that ytterbium suicide films had non-oriented blocks with the polycrystalline structure. The analysis of scanning region length dependencies of the root mean square roughness deviation (?R(L)) for grown suicide films has shown that the formation of ytterbium suicide in SPE and RDE growth methods is determined by the surface diffusion of Yb atoms during the three-dimensional growth process. Optical functions (n, k, ?, ?1, ?2, Im ?1-1, neff, ?eff) of ytterbium silicide films grown on Si(1 1 1) have been calculated from transmittance and reflectance spectra in the energy range of 0.1-6.2 eV. Two nearly discrete absorption bands have been observed in the electronic structure of Yb silicide films with different composition, which connected with interband transitions on divalent and trivalent Yb states. It was established that the reflection coefficient minimum in R-spectra at energies higher 4.2 eV corresponds to the state density minimum in Yb suicide between divalent and trivalent Yb states. It was shown from optical data that Yb silicide films have the semi-metallic properties with low state densities at energies less 0.4 eV and high state densities at 0.5-2.5 eV.

Galkin, N. G.; Maslov, A. M.; Polyarnyi, V. O.

2005-06-01

327

Yb:FAP and related materials, laser gain medium comprising same, and laser systems using same  

DOEpatents

An ytterbium doped laser material remarkably superior to all others, including Yb:YAG, comprises Ytterbium doped apatite (Yb:Ca.sub.5 (PO.sub.4).sub.3 F) or Yb:FAP, or ytterbium doped crystals that are structurally related to FAP. The new laser material is used in laser systems pumped by diode pump sources having an output near 0.905 microns or 0.98 microns, such as InGaAs and AlInGaAs, or other narrowband pump sources near 0.905 microns or 0.98 microns. The laser systems are operated in either the conventional or ground state depletion mode.

Krupke, William F. (Pleasanton, CA); Payne, Stephen A. (Castro Valley, CA); Chase, Lloyd L. (Livermore, CA); Smith, Larry K. (Salida, CA)

1994-01-01

328

Effect of Niobium on Yb:GdVO 4 single crystal  

NASA Astrophysics Data System (ADS)

A study was made on effect of niobium on the GdVO 4 crystal structure. Yb:GdV 0.995Nb 0.005O 4 crystals were grown by the Czochralski method, and their transmission spectra, absorption spectra, and fluorescence spectra were measured. The GdV 0.995Nb 0.005O 4 crystals acting as new laser host crystals do not affect the absorption of Yb 3+. Some spectrum parameters calculated by the Fuchbauer—Ladenburger method indicate that doping of Nb 5+ in the GdVO 4 crystal improves the spectroscopic properties of Yb 3+.

Chen, Jingling; Chen, Jianzhong; Lin, Conggui; Zhuang, Naifeng; Lin, Xinsong

2006-03-01

329

Fluorosilicate and fluorophosphate superfluorescent multicore optical fibers co-doped with Nd3+/Yb3+  

NASA Astrophysics Data System (ADS)

In the paper spectroscopic properties of two fluorosilicate and fluorophosphate glass systems co-doped with Nd3+/Yb3+ ions are investigated. As a result of optical excitation at the wavelength of 808 nm strong and wide emission in the 1 ?m region corresponding to the superposition of optical transitions 4F3/2 ? 4I11/2 (Nd3+) and 2F5/2 ? 2F7/2 (Yb3+) can be observed. The optimization of Nd3+ ? Yb3+ energy transfer in both glasses allows to manufacture multicore optical fibers with narrowing and red-shifting of amplified spontaneous emission (ASE) at 1.1 ?m.

Kochanowicz, M.; Zmojda, J.; Dorosz, D.

2014-06-01

330

Optimization of the cooling profile to achieve crack-free Yb:S-FAP crystals  

Microsoft Academic Search

Yb:S-FAP [Yb3+:Sr5(PO4)3F] crystals are an important gain medium for diode-pumped laser applications. Growth of 7.0cm diameter Yb:S-FAP crystals utilizing the Czochralski (CZ) method from SrF2-rich melts often encounters cracks during the post-growth cool-down stage. To suppress cracking during cool-down, a numerical simulation of the growth system was used to understand the correlation between the furnace power during cool-down and the

H. S. Fang; S. R. Qiu; L. L. Zheng; K. I. Schaffers; J. B. Tassano; J. A. Caird; H. Zhang

2008-01-01

331

Cold beam of isotopically pure Yb atoms by deflection using 1D-optical molasses  

NASA Astrophysics Data System (ADS)

We demonstrate generation of an isotopically pure beam of laser-cooled Yb atoms by deflection using 1D-optical molasses. Atoms in a collimated thermal beam are first slowed using a Zeeman Slower. They are then subjected to a pair of molasses beams inclined at $45^\\circ$ with respect to the slowed atomic beam. The slowed atoms are deflected and probed at a distance of 160 mm. We demonstrate selective deflection of the bosonic isotope $^{174}$Yb, and the fermionic isotope $^{171}$Yb. Using a transient measurement after the molasses beams are turned on, we find a longitudinal temperature of 41 mK.

Rathod, K. D.; Singh, P. K.; Natarajan, Vasant

2014-09-01

332

Elsevier Editorial System(tm) for Medical Image Analysis  

E-print Network

Angiography (CTA); Quantitative Coronary Angiography (QCA); Stenoses; Detection; Quantification; Lumen, in comparison with quantitative coronary angiography (QCA) and CTA consensus reading, and 2) (semiElsevier Editorial System(tm) for Medical Image Analysis Manuscript Draft Manuscript Number: MEDIA

Paris-Sud XI, Université de

333

Observation of the second proton alignment in {sup 160}Tm  

SciTech Connect

High-spin states in the doubly odd nucleus {sup 160}Tm have been investigated using the {sup 130}Te({sup 35}Cl,5n) reaction and the Euroball {gamma}-ray detector array. The previously established rotational structures in {sup 160}Tm were extended, leading to the first observation of the second (h{sub 11/2}){sup 2} proton band crossing in this nucleus. This crossing is found to occur at a higher rotational frequency in {sup 160}Tm than in lighter Tm isotopes. This trend resembles that of the first (h{sub 11/2}){sup 2} proton band crossing found in neighboring Er nuclei and is associated with a predicted increase in deformation as a function of neutron number in these isotopes.

Lagergren, K.; Riley, M.A.; Campbell, D.B. [Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States); Simpson, J.; Appelbe, D.E.; Joss, D.T. [CCLRC, Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Bednarczyk, P. [Institute de Recherches Subatomiques, F-67037 Strasbourg (France); Institute of Nuclear Physics PAN, Krakow (Poland); Chandler, C. [School of Chemistry and Physics, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Choy, P.T.W.; Paul, E.S. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Curien, D. [Institute de Recherches Subatomiques, F-67037 Strasbourg (France)

2005-11-01

334

Editorial Manager(tm) for International Congress Series Manuscript Draft  

E-print Network

Editorial Manager(tm) for International Congress Series Manuscript Draft Manuscript Number: 1268276. Burnside, MD, MPH, MS; Daniel L Rubin, MD, MS; Ross D Shachter, PhD Abstract: Mammography is the best test University, CA, USA ________________________________________________________________ Abstract. Mammography

Rubin, Daniel L.

335

ORNL/TM-2011/463 Preliminary Assessment of  

E-print Network

by Adam Siekmann Gary Capps Mary Beth Lascurain Hudson #12;ii ORNL/TM-2011/463 Energy and Transportation Science Division OVERWEIGHT VEHICLE ASSESSMENT Adam Siekmann Gary Capps Mary Beth Lascurain Hudson Date

336

ORNL/TM-2001/116 TRUCK ROLL STABILITY  

E-print Network

ORNL/TM-2001/116 TRUCK ROLL STABILITY DATA COLLECTION AND ANALYSIS S. S. Stevens, Principal-00OR22725 #12;#12;Truck Roll Stability iii June 19, 2001 CONTENTS LIST OF TABLES ...............................................................................................................11 3.4 Database Design

337

RETM5 and RE2TM17 permanent magnets development  

Microsoft Academic Search

RETM5 and RE2TM17 (RE = rare earth, TM = transition metal) permanent magnets are discussed. The scientific and technological considerations which have guided their development are described to help establish the framework within which most of the work can be integrated and understood. The review limits itself to the technologically significant SmCo5 material and to those processes which have been

Kaplesh Kumar

1988-01-01

338

Quiet Spike (TM) Build-Up Ground Vibration Testing Approach  

NASA Technical Reports Server (NTRS)

Flight tests of Gulfstream Aerospace Corporation s Quiet Spike(TM) hardware were recently completed on the NASA Dryden Flight Research Center F-15B airplane. NASA Dryden uses a modified F-15B airplane as a testbed aircraft to cost-effectively fly flight research experiments that are typically mounted underneath the F-15B airplane, along the fuselage centerline. For the Quiet Spike(TM) experiment, however, instead of a centerline mounting, a relatively long forward-pointing boom was attached to the radar bulkhead of the F-15B airplane. The Quiet Spike(TM) experiment is a stepping-stone to airframe structural morphing technologies designed to mitigate the sonic-boom strength of business jets over land. The Quiet Spike(TM) boom is a concept in which an aircraft's noseboom would be extended prior to supersonic acceleration. This morphing effectively lengthens the aircraft, thus reducing the peak sonic-boom amplitude, but is also expected to partition the otherwise strong bow shock into a series of reduced-strength, noncoalescing shocklets. Prior to flying the Quiet Spike(TM) experiment on the F-15B airplane several ground vibration tests were required to understand the Quiet Spike(TM) modal characteristics and coupling effects with the F-15B airplane. However, due to the flight hardware availability and compressed schedule requirements, a "traditional" ground vibration test of the mated F-15B Quiet Spike(TM) ready-for-flight configuration did not leave sufficient time available for the finite element model update and flutter analyses before flight testing. Therefore, a "nontraditional" ground vibration testing approach was taken. This paper provides an overview of each phase of the "nontraditional" ground vibration testing completed for the Quiet Spike(TM) project which includes the test setup details, instrumentation layout, and modal results obtained in support of the structural dynamic modeling and flutter analyses.

Spivey, Natalie D.; Herrera, Claudia; Truax, Roger; Pak, Chan-gi; Freund, Donald

2007-01-01

339

The ProphetTM risk management tool set  

Microsoft Academic Search

Raytheon has developed a powerful risk management tool set, named ProphetTM, which has proven highly successful in managing several programs, and is now being deployed throughout Raytheon. This paper describes ProphetTM features, the processes it supports, and the concepts behind them. Features include user-friendly input screens, roll-up risk factors, automated risk reduction charts, expected cost impact analysis, assessment history and

D. S. Huff

1999-01-01

340

RMS-TM: A TRANSACTIONAL MEMORY BENCHMARK FOR RECOGNITION, MINING AND SYNTHESIS APPLICATIONS  

Microsoft Academic Search

Transactional Memory (TM) is a new concurrency control mechanism that aims to make parallel programming for Chip MultiProcessors (CMPs) easier. Recently, this topic has re- ceived substantial research attention with various software and hardware TM proposals and designs that promise to make TM both more efficient. These proposals are usually analyzed using existing TM-benchmarks, however the per- formance evaluation of

Srdjan Stipic; Osman Unsal; Adrian Cristal; Mateo Valero

341

YB-1 expression promotes epithelial-to-mesenchymal transition in prostate cancer that is inhibited by a small molecule fisetin.  

PubMed

Epithelial-to-mesenchymal transition (EMT) plays an important role in prostate cancer (PCa) metastasis. The transcription/translation regulatory Y-box binding protein-1 (YB-1) is known to be associated with cancer metastasis. We observed that YB-1 expression increased with tumor grade and showed an inverse relationship with E-cadherin in a human PCa tissue array. Forced YB-1 expression induced a mesenchymal morphology that was associated with down regulation of epithelial markers. Silencing of YB-1 reversed mesenchymal features and decreased cell proliferation, migration and invasion in PCa cells. YB-1 is activated directly via Akt mediated phosphorylation at Ser102 within the cold shock domain (CSD). We next identified fisetin as an inhibitor of YB-1 activation. Computational docking and molecular dynamics suggested that fisetin binds on the residues from ?1 - ?4 strands of CSD, hindering Akt's interaction with YB-1. Calculated free binding energy ranged from -11.9845 to -9.6273 kcal/mol. Plasmon Surface Resonance studies showed that fisetin binds to YB-1 with an affinity of approximately 35 µM, with both slow association and dissociation. Fisetin also inhibited EGF induced YB-1 phosphorylation and markers of EMT both in vitro and in vivo. Collectively our data suggest that YB-1 induces EMT in PCa and identify fisetin as an inhibitor of its activation. PMID:24770864

Khan, Mohammad Imran; Adhami, Vaqar Mustafa; Lall, Rahul Kumar; Sechi, Mario; Joshi, Dinesh C; Haidar, Omar M; Syed, Deeba Nadeem; Siddiqui, Imtiaz Ahmad; Chiu, Shing-Yan; Mukhtar, Hasan

2014-05-15

342

YB-1 expression promotes epithelial-to-mesenchymal transition in prostate cancer that is inhibited by a small molecule fisetin  

PubMed Central

Epithelial-to-mesenchymal transition (EMT) plays an important role in prostate cancer (PCa) metastasis. The transcription/translation regulatory Y-box binding protein-1 (YB-1) is known to be associated with cancer metastasis. We observed that YB-1 expression increased with tumor grade and showed an inverse relationship with E-cadherin in a human PCa tissue array. Forced YB-1 expression induced a mesenchymal morphology that was associated with down regulation of epithelial markers. Silencing of YB-1 reversed mesenchymal features and decreased cell proliferation, migration and invasion in PCa cells. YB-1 is activated directly via Akt mediated phosphorylation at Ser102 within the cold shock domain (CSD). We next identified fisetin as an inhibitor of YB-1 activation. Computational docking and molecular dynamics suggested that fisetin binds on the residues from ?1 - ?4 strands of CSD, hindering Akt's interaction with YB-1. Calculated free binding energy ranged from ?11.9845 to ?9.6273 kcal/mol. Plasmon Surface Resonance studies showed that fisetin binds to YB-1 with an affinity of approximately 35 ?M, with both slow association and dissociation. Fisetin also inhibited EGF induced YB-1 phosphorylation and markers of EMT both in vitro and in vivo. Collectively our data suggest that YB-1 induces EMT in PCa and identify fisetin as an inhibitor of its activation. PMID:24770864

Khan, Mohammad Imran; Adhami, Vaqar Mustafa; Lall, Rahul Kumar; Sechi, Mario; Joshi, Dinesh C.; Haidar, Omar M.; Syed, Deeba Nadeem; Siddiqui, Imtiaz Ahmad; Chiu, Shing-Yan; Mukhtar, Hasan

2014-01-01

343

NONO and RALY proteins are required for YB-1 oxaliplatin induced resistance in colon adenocarcinoma cell lines  

PubMed Central

Background YB-1 is a multifunctional protein that affects transcription, splicing, and translation. Overexpression of YB-1 in breast cancers causes cisplatin resistance. Recent data have shown that YB-1 is also overexpress in colorectal cancer. In this study, we tested the hypothesis that YB-1 also confers oxaliplatin resistance in colorectal adenocarcinomas. Results We show for the first time that transfection of YB-1 cDNA confers oxaliplatin resistance in two colorectal cancer cell lines (SW480 and HT29 cell lines). Furthermore, we identified by mass spectrometry analyses important YB-1 interactors required for such oxaliplatin resistance in these colorectal cancer cell lines. A tagged YB-1 construct was used to identify proteins interacting directly to YB-1 in such cells. We then focused on proteins that are potentially involved in colorectal cancer progression based on the Oncomine microarray database. Genes encoding for these YB-1 interactors were also examined in the public NCBI comparative genomic hybridization database to determine whether these genes are localized to regions of chromosomes rearranged in colorectal cancer tissues. From these analyses, we obtained a list of proteins interacting with YB-1 and potentially involved in oxaliplatin resistance. Oxaliplatin dose response curves of SW480 and HT29 colorectal cancer cell lines transfected with several siRNAs corresponding to each of these YB-1 interactors were obtained to identify proteins significantly affecting oxaliplatin sensitivity upon gene silencing. Only the depletion of either NONO or RALY sensitized both colorectal cancer cell lines to oxaliplatin. Furthermore, depletion of NONO or RALY sensitized otherwise oxaliplatin resistant overexpressing YB-1 SW480 or HT29 cells. Conclusion These results suggest knocking down NONO or RALY significant counteracts oxaliplatin resistance in colorectal cancers overexpressing the YB-1 protein. PMID:22118625

2011-01-01

344

gamma. -ray decay and nuclear shapes in /sup 158/Yb  

SciTech Connect

The decay of the entry states in /sup 158/Yb populated in the reactions of 149 MeV /sup 20/Ne with /sup 144/Nd and /sup 146/Nd has been investigated with a 4 ..pi.. multidetector system gated by a Ge counter. The average exitation energy, the ..gamma..-ray spectra and the angular distributions as a function of multiplicity show several changes in the ..gamma..-ray decay. These changes suggest a transition from prolate to particle aligned oblate configuration at I approx. 28. At I 38 to 48 collective transitions with dipole and quadrupole component are observed. Possible explanations for these transitions are discussed in terms of nuclear shapes. Furthermore, above I approx. 48 the dipole component disappears suggesting a further change toward more triaxial shape. 19 references.

Jaeaeskelaeinen, M.; Sarantites, D.G.; Dilmanian, F.A.; Woodward, R.; Puchta, H.; Beene, J.R.; Hattula, J.; Halbert, M.L.; Hensley, D.C.

1982-01-01

345

High peak power gigahertz Yb:CALGO laser.  

PubMed

We present a high-power gigahertz SESAM modelocked Yb:CALGO laser with sub-60-fs pulses. The laser delivers an average output power of 2.95 W at a pulse repetition rate of 1.8 GHz in fundamental modelocking without additional pulse compression or amplification. Stable modelocking with a single pulse per cavity round-trip is confirmed and results in an output peak power of 24.3 kW and a pulse energy of 1.64 nJ. The laser is pumped by a commercial multimode diode laser, which improves the reliability and robustness. This high-power gigahertz laser is expected to enable numerous applications in frequency metrology. PMID:24921309

Klenner, Alexander; Golling, Matthias; Keller, Ursula

2014-05-19

346

Injection locking of Yb-fiber based optical frequency comb.  

PubMed

We demonstrated the synchronization of offset and repetition frequency between two independent Yb-doped fiber mode-locked lasers by injection locking. By injecting master-laser pulse-train into slave laser cavity, stability and accuracy of master frequency comb are transferred to slave comb. Passive stabilization of frequency comb offers robust and convenient way to duplicate frequency comb that can be applied to long-distance comb transfer. Injecting master pulse would also help to initiate and stabilize mode-locking of high repetition rate or ultrabroadband frequency combs. Additionally, we also demonstrated even more robust synchronization of combs can be achieved with the help of active stabilization of relative offset frequency difference. PMID:22565676

Kuse, Naoya; Ozawa, Akira; Nomura, Yutaka; Ito, Isao; Kobayashi, Yohei

2012-05-01

347

Length distributed measurement of temperature effects in Yb-doped fibers during pumping  

NASA Astrophysics Data System (ADS)

We demonstrate a distributed measurement technique to observe temperature changes along pumped Yb-doped fibers. This technique is based on an array of fiber Bragg gratings acting as a temperature sensor line. The Bragg gratings are inscribed directly into the Yb-doped fiber core using high-intensity ultrashort laser pulses and an interferometric setup. We studied the temperature evolution in differently co-doped Yb fibers during optical pumping and identified different effects contributing to the observed temperature increase. We found that preloading of fibers with hydrogen supports the formation of Yb during UV irradiation and has a large impact on fiber temperature during pumping. The proposed technique can be applied to investigate the homogeneity of pump absorption in active fibers and to support spatially resolved photodarkening measurements.

Leich, Martin; Fiebrandt, Julia; Schwuchow, Anka; Jetschke, Sylvia; Unger, Sonja; Jäger, Matthias; Rothhardt, Manfred; Bartelt, Hartmut

2014-06-01

348

Cooperative energy transfer in Yb3+-Tb3+ codoped silica sol-gel glasses  

NASA Astrophysics Data System (ADS)

Optical properties of Yb3+-Tb3+ codoped silica sol-gel samples have been studied after the gel to glass transition. Different upconversion emissions have been observed under near infrared excitation at about 1 ?m. The Tb3+ ions are excited by means of energy transfer processes from Yb3+ ions. The temporal evolution of the blue-green upconversion emissions coming from Tb3+ ions and their dependence on the excitation intensity at about 1 ?m has been studied. The experimental results are in good agreement with a cooperative resonant energy transfer mechanism from Yb3+ ions. An efficient backtransfer process is observed from Tb3+ ions towards Yb3+ ions. The upconversion efficiency, which is limited by this backtransfer process, has been obtained and compared with other upconversion results in similar matrix.

Martín, I. R.; Yanes, A. C.; Méndez-Ramos, J.; Torres, M. E.; Rodríguez, V. D.

2001-03-01

349

Quantum cutting mechanism in Tb3+-Yb3+ co-doped oxyfluoride glass  

NASA Astrophysics Data System (ADS)

Rate equations were created to describe cooperative quantum cutting phenomena, which incorporated the interactions between donor Tb3+ and acceptor Yb3+ ions. Two judgment criteria were developed for the excitation power dependence and time-resolved luminescence spectra of donor and acceptor ions, which can be used to verify the proposed mechanism. Under the excitation of a 473 nm continuous wave laser, the emission intensities of Tb3+ and Yb3+ increased linearly with the excitation power. The decay curve of Yb3+ indicated two distinct contributions: the fast decay time of its own lifetime, and the slow decay time representing the lifetime of the 5D4 energy level of Tb3+. The experimental results meet the two judgment criteria, which confirmed the proposed cooperative quantum cutting mechanism in Tb3+-Yb3+ co-doped oxyfluoride glass.

Duan, Qianqian; Qin, Feng; Wang, Dan; Xu, Wei; Cheng, Jianmin; Zhang, Zhiguo; Cao, Wenwu

2011-12-01

350

On the anisotropy of the magnetic properties of CsYbZnSe3.  

PubMed

DC magnetic susceptibility measurements on CsYbZnSe 3 show a broad magnetic transition at approximately 10 K and pronounced differences between zero-field-cooled and field-cooled data that lead to experimental effective magnetic moments of 4.26(5) BM and 4.39(4) BM, respectively. Specific heat measurements confirm that there is neither long-range ordering nor a phase transition between 1.8 and 380 K. First-principles electronic structure calculations with and without inclusion of spin-orbit coupling effects show that the spins of CsYbZnSe 3 prefer to orient along [010] rather than along either [100] or [001] of this orthorhombic material and that the spin exchange between adjacent Yb3+ ions along [100] is substantially antiferromagnetic. The magnetic properties of CsYbZnSe 3 are best described by an Ising uniform antiferromagnetic chain model. PMID:18257547

Chan, George H; Lee, Changhoon; Dai, Dadi; Whangbo, Myung-Hwan; Ibers, James A

2008-03-01

351

Influence of other rare earth ions on the optical refrigeration efficiency in Yb:YLF crystals.  

PubMed

We investigated the effect of rare earth impurities on the cooling efficiency of Yb3+:LiYF4 (Yb:YLF). The refrigeration performance of two single crystals, doped with 5%-at. Yb and with identical history but with different amount of contaminations, have been compared by measuring the cooling efficiency curves. Spectroscopic and elemental analyses of the samples have been carried out to identify the contaminants, to quantify their concentrations and to understand their effect on the cooling efficiencies. A model of energy transfer processes between Yb and other rare earth ions is suggested, identifying Erbium and Holmium as elements that produce a detrimental effect on the cooling performance. PMID:25402099

Di Lieto, Alberto; Sottile, Alberto; Volpi, Azzurra; Zhang, Zhonghan; Seletskiy, Denis V; Tonelli, Mauro

2014-11-17

352

Alumina Paste Layer as a Sublimation Suppression Barrier for Yb14MnSb11  

NASA Technical Reports Server (NTRS)

Sublimation is a major cause of degradation of thermoelectric power generation systems. Most thermoelectric materials tend to have peak values at the temperature where sublimation occurs. A sublimation barrier is needed that is stable at operating temperatures, inert against thermoelectric materials, and able to withstand thermal cycling stress. A porous alumina paste layer is suitable as a sublimation barrier for Yb14MnSb11. It can accommodate stress generated by the thermal expansion discrepancy between the suppression layer and thermoelectric materials. Sublimation suppression is achieved by filling pores naturally with YbO2, a natural byproduct of sublimation. YbO2 generated during the sublimation of Yb14MnSb11 fills the porous structure of the alumina paste, causing sublimation to decrease with time as the pores become filled.

Paik, Jong-Ah; Caillat, Thierry

2010-01-01

353

Large core Yb-doped optical fiber through vapor phase doping technique  

NASA Astrophysics Data System (ADS)

Rare earth (RE) doped optical fibers have shown tremendous progress for producing high power fiber lasers for industrial, medical and strategic applications. However, fabrication of large core, high Yb-doped fiber is still a challenge through conventional process due to poor repeatability and limitation regarding core size. This paper presents successful fabrication of Yb-doped fibers through vapor phase doping technique. Preform fabrication was carried out using a specially constructed MCVD system containing High Temperature Vapor Delivery Unit with sublimators for Al and Yb precursors. The novelty of the present work lies in deposition of Al2O3 and Yb2O3 in vapor phase simultaneously with silica during formation of sintered core layer which result in uniform dopants distribution in the preform. The fibers exhibited lasing efficiency of 76% with low `photodarkening effect'.

Saha, Maitreyee; Pal, Atasi; Pal, Mrinmay; Sen, Ranjan

2013-05-01

354

Asynchronous modelocked Yb:KYW lasers for dual-comb spectroscopy  

E-print Network

oscillator, or by locking two teeth of each individual FC to two stabilised single-fre- quency narrow identical modelocked Yb:KYW lasers similar to that described in [4]. Both lasers were pumped by singlemode

355

Optimization of the cooling profile to achieve crack-free Yb:S-FAP crystals  

SciTech Connect

Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F] crystals are an important gain medium for diode-pumped laser applications. Growth of 7.0 cm diameter Yb:S-FAP crystals utilizing the Czochralski (CZ) method from SrF{sub 2}-rich melts often encounter cracks during the post growth cool down stage. To suppress cracking during cool down, a numerical simulation of the growth system was used to understand the correlation between the furnace power during cool down and the radial temperature differences within the crystal. The critical radial temperature difference, above which the crystal cracks, has been determined by benchmarking the simulation results against experimental observations. Based on this comparison, an optimal three-stage ramp-down profile was implemented and produced high quality, crack-free Yb:S-FAP crystals.

Fang, H; Qiu, S; Kheng, L; Schaffers, K; Tassano, J; Caird, J; Zhang, H

2007-08-20

356

Yb growth on Ni(100) studied by XPS inelastic background analysis  

NASA Astrophysics Data System (ADS)

A recently proposed formalism for quantitative analysis of surface electron spectra is applied to an XPS study of Yb growth on a Ni(100) surface. It is found that this formalism can, by a simple analysis of a single electron spectrum, provide detailed information on the in-depth profile composition within the surface region of the sample. The uncertainty in the analysis is also investigated. Yb growth is found to proceed by a Stranski-Krastanov growth mode. Island formation is found after an ~ 9 Å Yb overlayer thickness. Sample annealing at 400°C results in the formation of an alloy in the surface region with the approximate composition Ni 0.75Yb 0.25.

Tougaard, S.; Hansen, H. S.

1990-10-01

357

Temperature dependence of Eu 4f and Eu 5d spin magnetizations in the filled skutterudite EuFe4Sb12  

SciTech Connect

The element specific and shell specific magnetism of Eu in the filled skutterudite ferrimagnet Eu0.95Fe4Sb12 has been investigated using Eu M4,5 and Eu L2,3 edge x-ray magnetic circular dichroism (XMCD) spectroscopy as a function of temperature. Eu L3 edge and Eu M5 edge x-ray absorption spectroscopy clearly show that Eu is in a mixed valence state. Sum rule analysis of the Eu M4,5 edge XMCD spectrum measured at 4.9K yielded the 4f spin moment of 7.15+/-0.3uB per Eu2+ ion. By comparing the Eu L2,3 edge XMCD spectrum in the ferrimagnetic state of Eu0.95Fe4Sb12 and the divalent Eu reference compound, the clathrate Eu8Ga16Ge30, we show that the 5d magnetic moment of Eu in the skutterudite is strongly enhanced by the exchange coupling with the 3d band electrons of Fe, which were shown to have an ordered moment of -0.21uB/Fe in our earlier Fe L2,3 XMCD measurements. The temperature dependence of the ferromagnetic order parameter, determined from the Eu L3 edge XMCD intensity, yields a mean field like exponent (~0.52) in the skutterudite and a 3D Heisenberg like (~0.36) exponent in the clathrate.

Krishnamurthy, Vemuru [Oak Ridge National Laboratory (ORNL); Keavney, D. J. [Argonne National Laboratory (ANL); Haskel, D. [Argonne National Laboratory (ANL); Lang, J. C. [Argonne National Laboratory (ANL); Srajer, G. [Argonne National Laboratory (ANL); Sales, Brian C [ORNL; Robertson, Lee [ORNL; Mandrus, David [ORNL

2009-01-01

358

Modeling and experimental characterization of Blackglas(TM) polymer pyrolysis to ceramic and thermodynamic characterization of Blackglas(TM) ceramic  

Microsoft Academic Search

The transformation of Blackglas(TM) polymer to ceramic is characterized by TGA-RGA\\/MS, Si29 and C13 NMR. Si29 NMR reveals a dependence between the postcure temperature and the microstructure of the resin. The postcure temperature that appears to give optimal mechanical and oxidative properties of Blackglas(TM) ceramic is around 150°C. The pyrolysis processing models, which are the Lumped Parameters Model (LPM), the

Feng Wang

2000-01-01

359

Analysis of Brand Recognition Associated with the Texas SuperstarTM and Earth-KindTM Programs in Texas  

E-print Network

ANALYSIS OF BRAND RECOGNITION ASSOCIATED WITH THE TEXAS SUPERSTAR TM AND EARTH-KIND TM PROGRAMS IN TEXAS A Thesis by ALBA JEANETTE COLLART DINARTE Submitted to the Office of Graduate Studies of Texas A&M University in partial... by ALBA JEANETTE COLLART DINARTE Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Co-Chairs of Committee, David A. Bessler...

Collart Dinarte, Alba Jeanette.

2010-10-12

360

Comparison of Hydrofluoroalkane-Beclomethasone Dipropionate AutohalerTM with Budesonide TurbuhalerTM in Asthma Control  

Microsoft Academic Search

Background: Hydrofluoroalkane-beclomethasone dipropionate AutohalerTM (HFA-BDP AH) is a breath-actuated chlorofluorocarbon (CFC)-free metered dose inhaler in which BDP is in a solution of HFA propellant. Budesonide TurbuhalerTM (BUD TH) is a breath-dependent dry powder inhaler. Objectives: To test the hypothesis that half the daily dose of HFA-BDP AH would provide an equivalent control of asthma symptoms to the BUD TH. Methods:

H. Worth; J. F. Muir; W. R. Pieters

2001-01-01

361

Modeling high-power Er3+Yb3+ codoped fiber lasers  

Microsoft Academic Search

High-power cladding-pumped Er3+-Yb3+ codoped fiber lasers (EYDFL) are analyzed with a detailed rate-equations model that takes into account the energy transfer between Yb3+ and Er3+. Examples of EYDFL with distributed Bragg reflector (DBR) mirrors at both fiber ends are demonstrated. Approximate quasi-analytical solutions to the rate equations show good agreement with the exact numerical solutions for practical operating conditions. An

Eldad Yahel; Amos Hardy

2003-01-01

362

Fiber-DFB laser array pumped with a single 1-W CW Yb-fiber laser  

Microsoft Academic Search

A 50-GHz grid fiber distributed feedback laser wavelength-division-multiplexing transmitter source is demonstrated pumped by a single continuous-wave Yb-fiber laser source at 977 nm. Up to 21 mW of output power is achieved per channel with maintenance of key operational parameters. The performance of this single Yb-fiber laser pump configuration is also compared with that of a semiconductor pump configuration which

L. B. Fu; R. Selvas; M. Ibsen; J. K. Sahu; J. N. Jang; S.-U. Alam; J. Nilsson; D. J. Richardson; D. N. Payne; C. Codemard; S. Goncharov; I. Zalevsky; A. B. Grudinin

2003-01-01

363

Cooperative energy transfer in Yb3+–Tb3+ codoped silica sol-gel glasses  

Microsoft Academic Search

Optical properties of Yb3+–Tb3+ codoped silica sol-gel samples have been studied after the gel to glass transition. Different upconversion emissions have been observed under near infrared excitation at about 1 ?m. The Tb3+ ions are excited by means of energy transfer processes from Yb3+ ions. The temporal evolution of the blue-green upconversion emissions coming from Tb3+ ions and their dependence

I. R. Mart?´n; A. C. Yanes; J. Me´ndez-Ramos; M. E. Torres; V. D. Rodr?´guez

2001-01-01

364

Cooperative energy transfer in Yb3+Tb3+ codoped silica sol-gel glasses  

Microsoft Academic Search

Optical properties of Yb3+-Tb3+ codoped silica sol-gel samples have been studied after the gel to glass transition. Different upconversion emissions have been observed under near infrared excitation at about 1 mum. The Tb3+ ions are excited by means of energy transfer processes from Yb3+ ions. The temporal evolution of the blue-green upconversion emissions coming from Tb3+ ions and their dependence

I. R. Martín; A. C. Yanes; J. Méndez-Ramos; M. E. Torres; V. D. Rodríguez

2001-01-01

365

Performance of YB 66 double-crystal monochromator for dispersing synchrotron radiation at SPring8  

Microsoft Academic Search

In the 1–2keV range, we adopted YB66 crystal for dispersing synchrotron radiation of the beamline No.15 (BL15XU) at SPring-8. YB66 crystal has a large d-value of 0.586nm for the 400 reflection and is useful as a soft X-ray monochromator for dispersing synchrotron radiation, since there is no intrinsic absorption edge and it is more resistant than other crystals to synchrotron

Masaru Kitamura; Hideki Yoshikawa; Tetsuro Mochizuki; Aurel Mihai Vlaicu; Atsushi Nisawa; Nobuhiro Yagi; Masato Okui; Masahiro Kimura; Takaho Tanaka; Sei Fukushima

2003-01-01

366

Photoluminescence of ZnGa 2 O 4 doped with Mn, Yb, Sm, and Tb  

Microsoft Academic Search

ZnGa2O4 samples doped with Mn, Yb, Sm, and Tb have been prepared by a ceramic processing technique, and their 20°C photoluminescence\\u000a spectra were measured. The results demonstrate that the four dopants have a significant effect on the photoluminescence of\\u000a ZnGa2O4. Doping with Mn and Yb allows the peaks in the red spectral region to remain narrow and increases the PL

V. F. Zhitari; S. P. Muntean; V. I. Pavlenko

2009-01-01

367

3 GHz, fundamentally mode-locked, femtosecond Yb-fiber laser.  

PubMed

We demonstrate a fundamentally mode-locked Yb-fiber laser with 3 GHz repetition rate and ?206??fs pulse duration. The laser incorporates two enabling technologies: a 1 cm heavily Yb-doped phosphate glass fiber as the gain medium and a high-dispersion (-1300??fs2) output coupler to manage cavity dispersion. The oscillator self-starts and generates up to 53 mW average power. PMID:22940936

Chen, Hung-Wen; Chang, Guoqing; Xu, Shanhui; Yang, Zhongmin; Kärtner, Franz X

2012-09-01

368

Synthesis, Structure, and Transport Properties of YbSb2Te4 and YbSb4Te7 for Thermoelectric Applications  

NASA Technical Reports Server (NTRS)

Very little work has been done in the Yb-Sb-Te system of compounds. Exploratory synthesis of various compounds in the system has been performed in the search for new thermoelectric materials. The compounds in the system were examined due to the fact that the system is known to act as a concentrated Kondo system, a heavy fermion. Heavy fermions are known to possess high densities of state which are useful in thermoelectric applications. TWO compounds in the system, YbSb2Te4 and YbSb4Te7, have been successfully synthesized in bulk by two methods: low temperature mechanical alloying and high temperature direct synthesis. The Hall mobility, Seebeck coefficient, electrical resistivity, and thermal conductivity were measured on both the unannealed and annealed compounds up to 550 C to determine the dimensionless thermoelectric figure of merit, ZT. The results indicate that both compounds make promising candidates for use in thermoelectric devices.

Guloy, Amado S.

2005-01-01

369

Spectroscopy and radiation trapping of Yb3+ ions in lead phosphate glasses  

NASA Astrophysics Data System (ADS)

This paper reports ytterbium-doped lead phosphate (PbPhYb) glasses made by melt-quenching technique and their linear and nonlinear refractive indices. Raman and FTIR spectral analysis has been carried out to investigate the functional groups that constitute the host matrix. The oscillator strength of the absorption transition, (2F7/2?2F5/2) has been evaluated by using the Smakula model for various concentrations. The near infra-red emission and excitation spectra have been investigated and observed that the profile of the emission spectra changes as a function of Yb2O3 concentration, temperature, optical path length and thickness of the sample. From the optical absorption spectra, the spectroscopic and laser performance parameters have been evaluated and in turn used to estimate the gain cross-section of the Yb3+ ions. On the other hand, the lifetime for the 2F5/2 level of Yb3+ ion decreases with increase in Yb2O3 concentration up to 6 mol% after an initial increase due to energy migration among the Yb3+ ions. The increase in lifetime could be due to radiation trapping but when the concentration is enlarged the energy migration processes are more predominant. The emission profile and lifetime change when the temperature is reduced to cryogenic temperature (11 K). The results reveal that the prepared glasses could be considered for high energy and high power laser as well as solid state cryocooler applications.

Venkata Krishnaiah, K.; Rajeswari, R.; Upendra Kumar, K.; Surendra Babu, S.; Martín, I. R.; Jayasankar, C. K.

2014-06-01

370

Lanthanide near infrared imaging in living cells with Yb3+ nano metal organic frameworks  

PubMed Central

We have created unique near-infrared (NIR)–emitting nanoscale metal-organic frameworks (nano-MOFs) incorporating a high density of Yb3+ lanthanide cations and sensitizers derived from phenylene. We establish here that these nano-MOFs can be incorporated into living cells for NIR imaging. Specifically, we introduce bulk and nano-Yb-phenylenevinylenedicarboxylate-3 (nano-Yb-PVDC-3), a unique MOF based on a PVDC sensitizer-ligand and Yb3+ NIR-emitting lanthanide cations. This material has been structurally characterized, its stability in various media has been assessed, and its luminescent properties have been studied. We demonstrate that it is stable in certain specific biological media, does not photobleach, and has an IC50 of 100 ?g/mL, which is sufficient to allow live cell imaging. Confocal microscopy and inductively coupled plasma measurements reveal that nano-Yb-PVDC-3 can be internalized by cells with a cytoplasmic localization. Despite its relatively low quantum yield, nano-Yb-PVDC-3 emits a sufficient number of photons per unit volume to serve as a NIR-emitting reporter for imaging living HeLa and NIH 3T3 cells. NIR microscopy allows for highly efficient discrimination between the nano-MOF emission signal and the cellular autofluorescence arising from biological material. This work represents a demonstration of the possibility of using NIR lanthanide emission for biological imaging applications in living cells with single-photon excitation. PMID:24108356

Foucault-Collet, Alexandra; Gogick, Kristy A.; White, Kiley A.; Villette, Sandrine; Pallier, Agnes; Collet, Guillaume; Kieda, Claudine; Li, Tao; Geib, Steven J.; Rosi, Nathaniel L.; Petoud, Stephane

2013-01-01

371

Lanthanide near infrared imaging in living cells with Yb3+ nano metal organic frameworks.  

PubMed

We have created unique near-infrared (NIR)-emitting nanoscale metal-organic frameworks (nano-MOFs) incorporating a high density of Yb(3+) lanthanide cations and sensitizers derived from phenylene. We establish here that these nano-MOFs can be incorporated into living cells for NIR imaging. Specifically, we introduce bulk and nano-Yb-phenylenevinylenedicarboxylate-3 (nano-Yb-PVDC-3), a unique MOF based on a PVDC sensitizer-ligand and Yb(3+) NIR-emitting lanthanide cations. This material has been structurally characterized, its stability in various media has been assessed, and its luminescent properties have been studied. We demonstrate that it is stable in certain specific biological media, does not photobleach, and has an IC50 of 100 ?g/mL, which is sufficient to allow live cell imaging. Confocal microscopy and inductively coupled plasma measurements reveal that nano-Yb-PVDC-3 can be internalized by cells with a cytoplasmic localization. Despite its relatively low quantum yield, nano-Yb-PVDC-3 emits a sufficient number of photons per unit volume to serve as a NIR-emitting reporter for imaging living HeLa and NIH 3T3 cells. NIR microscopy allows for highly efficient discrimination between the nano-MOF emission signal and the cellular autofluorescence arising from biological material. This work represents a demonstration of the possibility of using NIR lanthanide emission for biological imaging applications in living cells with single-photon excitation. PMID:24108356

Foucault-Collet, Alexandra; Gogick, Kristy A; White, Kiley A; Villette, Sandrine; Pallier, Agnès; Collet, Guillaume; Kieda, Claudine; Li, Tao; Geib, Steven J; Rosi, Nathaniel L; Petoud, Stéphane

2013-10-22

372

Compositional dependence of room-temperature Stark splitting of Yb³? in several popular glass systems.  

PubMed

The room-temperature Stark splitting properties of Yb3+ are practical and valuable for lasers because the working temperature of the gain media intensively increases with the laser output. In this Letter, the room-temperature Stark splitting properties of Yb3+ in several popular laser glasses are contrastively studied. Yb3+-doped germanate (Ge), borate (B), silicate (Si), bismuthate (Bi), tellurite (Te), and fluorophosphate (FP) glasses exhibit large Stark splitting and tend to operate close to the quasi-four-level scheme, whereas phosphate (P) glass shows the weakest Stark splitting and tends to operate close to the quasi-three-level one. Due to the low thermal conductivity of the glass matrix, Yb3+-doped P glass suffers from serious thermal problems and is difficult to achieve high laser output. The Stark splitting is also used to estimate the crystal-field strength of glass hosts and local Yb3+ ligand asymmetry degree. The results show that P glass shows weaker crystal-field effect and lower Yb3+ ligand asymmetry than Ge, Si, and B glasses. PMID:24686601

Yang, Binhua; Liu, Xueqiang; Wang, Xin; Zhang, Junjie; Hu, Lili; Zhang, Liyan

2014-04-01

373

Thermodynamic and transport properties of single crystalline RCo2Ge2 (R=Y, La-Nd, Sm-Tm)  

NASA Astrophysics Data System (ADS)

Single crystals of RCo2Ge2 (R=Y, La-Nd, Sm-Tm) were grown using a self-flux method and were characterized by room-temperature powder X-ray diffraction; anisotropic, temperature and field dependent magnetization; temperature and field dependent, in-plane resistivity; and specific heat measurements. In this series, the majority of the moment-bearing members order antiferromagnetically; YCo2Ge2 and LaCo2Ge2 are non-moment-bearing. Ce is trivalent in CeCo2Ge2 at high temperatures, and exhibits an enhanced electronic specific heat coefficient due to the Kondo effect at low temperatures. In addition, CeCo2Ge2 shows two low-temperature anomalies in temperature-dependent magnetization and specific heat measurements. Three members (R=Tb-Ho) have multiple phase transitions above 1.8 K. Eu appears to be divalent with total angular momentum L=0. Both EuCo2Ge2 and GdCo2Ge2 manifest essentially isotropic paramagnetic properties consistent with J=S=7/2. Clear magnetic anisotropy for rare-earth members with finite L was observed, with ErCo2Ge2 and TmCo2Ge2 manifesting planar anisotropy and the rest members manifesting axial anisotropy. The experimentally estimated crystal electric field (CEF) parameters B20 were calculated from the anisotropic paramagnetic ?ab and ?c values and follow a trend that agrees well with theoretical predictions. The ordering temperatures, TN, as well as the polycrystalline averaged paramagnetic Curie-Weiss temperature, ?avg, for the heavy rare-earth members deviate from the de Gennes scaling, as the magnitude of both is the highest for Tb, which is sometimes seen for extremely axial systems. Except for SmCo2Ge2, metamagnetic transitions were observed at 1.8 K for all members that ordered antiferromagnetically.

Kong, Tai; Cunningham, Charles E.; Taufour, Valentin; Bud'ko, Sergey L.; Buffon, Malinda L. C.; Lin, Xiao; Emmons, Heather; Canfield, Paul C.

2014-05-01

374

Rare-earth metal gallium silicides via the gallium self-flux method. Synthesis, crystal structures, and magnetic properties of RE(Ga1-xSix)2 (RE=Y, La-Nd, Sm, Gd-Yb, Lu)  

NASA Astrophysics Data System (ADS)

Fifteen ternary rare-earth metal gallium silicides have been synthesized using molten Ga as a molten flux. They have been structurally characterized by single-crystal and powder X-ray diffraction to form with three different structures—the early to mid-late rare-earth metals RE=La-Nd, Sm, Gd-Ho, Yb and Y form compounds with empirical formulae RE(GaxSi1-x)2 (0.38?x?0.63), which crystallize with the tetragonal ?-ThSi2 structure type (space group I41/amd, No. 141; Pearson symbol tI12). The compounds of the late rare-earth crystallize with the orthorhombic ?-GdSi2 structure type (space group Imma, No. 74; Pearson symbol oI12), with refined empirical formula REGaxSi2-x-y (RE=Ho, Er, Tm; 0.33?x?0.40, 0.10?y?0.18). LuGa0.32(1)Si1.43(1) crystallizes with the orthorhombic YbMn0.17Si1.83 structure type (space group Cmcm, No. 63; Pearson symbol oC24). Structural trends are reviewed and analyzed; the magnetic susceptibilities of the grown single-crystals are presented.

Darone, Gregory M.; Hmiel, Benjamin; Zhang, Jiliang; Saha, Shanta; Kirshenbaum, Kevin; Greene, Richard; Paglione, Johnpierre; Bobev, Svilen

2013-05-01

375

Photoexcitation of Yb-doped aluminosilicate fibers at 250 nm: evidence for excitation transfer from oxygen deficiency centers to Yb{sup 3+}  

SciTech Connect

Emission spectra in the {approx}240-1100 nm wavelength region as well as the temporally resolved decay of Yb{sup 3+} and point defect spontaneous emission have been recorded when aluminosilicate optical fibers doped with Yb are irradiated with {approx}160 fs laser pulses having a central wavelength of {approx}250 nm (({Dirac_h}/2{pi}){omega}=5 eV). Photoexcitation of the fibers in this region of the deep ultraviolet (UV) provides access simultaneously to the Type II Si oxygen deficiency center (ODC), the non-bridging oxygen hole center (NBOHC: an oxygen-excess defect), and the Ge ODC. Emission from all of these defects in the ultraviolet and/or visible is observed, as is intense fluorescence at 976 nm from Yb{sup 3+}. Absorption measurements conducted in the {approx}230-265 nm region with a sequence of UV light-emitting diodes reveal a continuum peaking at {approx}248 nm and having a spectral width of {approx}18 nm (FWHM), confirming that the 250 nm laser pump is photoexciting predominantly the ODC. The temporal histories of the optically active defect and rare earth ion emission waveforms, in combination with time-integrated spectra, suggest that the Si ODC(II) triplet state directly excites Yb{sup 3+} as well as at least one other intrinsic defect in the silica network. Prolonged exposure of the Yb-doped fibers to 250 nm radiation yields increased Yb{sup 3+}, NBOHC, and Si ODC(II) singlet emission which is accompanied by a decline in Si ODC(II) triplet fluorescence, thus reinforcing the conclusion--drawn on the basis of luminescence decay constants--that the triplet state of Si ODC(II) is the immediate precursor to the NBOHC and is partially responsible for Yb ion emission at 976 nm. This conclusion is consistent with the observation that exposure of fiber to 5 eV radiation slightly suppresses ODC absorption in the {approx}240-255 nm region while simultaneously introducing an absorption continuum extending from 260 nm to below 235 nm (({Dirac_h}/2{pi}){omega}{approx_equal}5.28 eV). These results suggest that ODC{yields}E{sup '} center conversion assumes a role in excitation transfer to Yb{sup 3+}.

Carlson, C. G. [Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Present address: Laser and Optics Research Center, USAF Academy, Colorado Springs, Colorado 80840 (United States); Keister, K. E.; Dragic, P. D.; Eden, J. G. [Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Croteau, A. [INO, 2740 Einstein Street, Quebec City, Quebec G1P 4S4 (Canada)

2010-10-15

376

Ferromagnetic behavior in mixed valence europium (Eu2+/Eu3+) oxide EuTi1-xMxO3 (M = Al3+ and Ga3+)  

NASA Astrophysics Data System (ADS)

We have investigated the Ti-site substitution effect on the magnetic properties of antiferromagnetic insulator EuTiO3 with a Néel temperature of ˜5 K. Partial substitution of Ti4+ with heterovalent Al3+ or Ga3+ turns the corresponding amount of magnetic Eu2+ into non-magnetic Eu3+. Both EuTi1-xAlxO3 (0.05 ? x ? 0.10) and EuTi1-xGaxO3 (0.05 ? x ? 0.10) exhibit ferromagnetic (FM) insulating behavior below ˜4 K. The Eu2+/Eu3+ mixed valence state probably contributes to the emergence of the FM behavior. Fine control of the magneto-electric (ME) phases of EuTi1-xAlxO3 and EuTi1-xGaxO3 would lead to intriguing ME phenomena such as giant ME effect.

Akahoshi, Daisuke; Horie, Hiroki; Sakai, Shingo; Saito, Toshiaki

2013-10-01

377

Journal of Crystal Growth 304 (2007) 114117 Single crystal growth of YbRh2Si2 using Zn flux  

E-print Network

Journal of Crystal Growth 304 (2007) 114�117 Single crystal growth of YbRh2Si2 using Zn flux-temperature solution technique, using Zn flux and followed by a decanting process. As opposed from the crystals growth: A1. Growth from high-temperature solutions; A1. Single crystal; B2. YbRh2Si2 1. Introduction YbRh2Si

Broholm, Collin Leslie

378

The Allocation of EU Budget Before and After Enlargement  

Microsoft Academic Search

Abstract A declared objective of the EU is to provide support for the rural and poor regions of its member states. Recent research shows, however, that past EU budget allocations (in EU-15) can be explained, to a large extent, by measures of the distribution of voting power in the Council of Ministers deciding on the bulk of EU spending. Yet,

Heikki Kauppi; Mika Widgren

379

Voting Rules and Budget Allocation in an Enlarged EU  

Microsoft Academic Search

The EU declares to provide support for the rural and poor regions of its member states. However, recent research shows that past EU budget allocations (in EU-15) can largely be explained by measures of the distribution of voting power in the Council of Ministers deciding on the bulk of EU spending. Yet, empirical analysis also indicates that the needs of

Heikki Kauppi; Mika Widgrén

2005-01-01

380

Functionality in EU Foreign Policy: Towards a New Research Agenda?  

Microsoft Academic Search

The study of European Union (EU) foreign policy has hitherto been dominated by the question of effectiveness, i.e. does it work? This takes the external impact of the EU’s foreign policy as its analytical starting point. In addition to asking whether EU foreign policy works, we should also inquire into its functions. The article identifies three functions served by EU

Christopher J. Bickerton

2010-01-01

381

ADAPTATION OF THE EU COMPETITION POLICY IN SLOVAKIA - SELECTED PROBLEMS  

Microsoft Academic Search

1. State aid regulation in the new EU Member States In order to prepare for a gradual introduction of the State aid control in line with the EU acquis, the EU has been working for many years closely with the authorities in the Acceding States. Since the late 1990s, the EU has actively encouraged the introduction of State aid legislation

Zuzana Mogyorosiová

382

IN OR OUT OF THE EU? HOW BRITISH NEWSPAPERS  

E-print Network

IN OR OUT OF THE EU? HOW BRITISH NEWSPAPERS FRAME THE EU REFERENDUM Bachelor thesis in the Double.07.2013 Unterschrift: #12;2013-07-15 2 Table of Contents Table of tables 4 1. Introduction 6 2. The British EU.3. Operationalization and coding 16 5. Findings 17 5.1. Which frames do British newspapers use in covering the EU

Vellekoop, Michel

383

Emission behaviors of Yb2O3 nanoparticles pumped by 980 nm laser at different power densities  

NASA Astrophysics Data System (ADS)

Yb2O3 nanoparticles synthesized via Pechini type sol-gel method were characterized by TEM, SAED, EDS, XRD, SEM and Raman spectrometer. Their emission properties were recorded by a fluorescence spectrophotometer with a 980 nm laser as the excitation source. These spectral results indicate that there are two optical bistable emissions at low/high laser power densities, i.e. Yb3+-Yb3+ dimer cooperative upconversion luminescence and thermal emission. Thus, Yb2O3 nanoparticles might be regarded as a candidate for intrinsic optical bistability.

Zheng, Youjin; Lü, Qiang; Wang, Jialiang; Zhang, Guohai; Gao, Yang; Liu, Zhanbo

2014-11-01

384

The proteolytic YB-1 fragment interacts with DNA repair machinery and enhances survival during DNA damaging stress.  

PubMed

The Y-box binding protein 1 (YB-1) is a DNA/RNA-binding nucleocytoplasmic shuttling protein whose regulatory effect on many DNA and RNA-dependent events is determined by its localization in the cell. We have shown previously that YB-1 is cleaved by 20S proteasome between E219 and G220, and the truncated N-terminal YB-1 fragment accumulates in the nuclei of cells treated with DNA damaging drugs. We proposed that appearance of truncated YB-1 in the nucleus may predict multiple drug resistance. Here, we compared functional activities of the full-length and truncated YB-1 proteins and showed that the truncated form was more efficient in protecting cells against doxorubicin treatment. Both forms of YB-1 induced changes in expression of various genes without affecting those responsible for drug resistance. Interestingly, although YB-1 cleavage did not significantly affect its DNA binding properties, truncated YB-1 was detected in complexes with Mre11 and Rad50 under genotoxic stress conditions. We conclude that both full-length and truncated YB-1 are capable of protecting cells against DNA damaging agents, and the truncated form may have an additional function in DNA repair. PMID:24107631

Kim, Ekaterina R; Selyutina, Anastasia A; Buldakov, Ilya A; Evdokimova, Valentina; Ovchinnikov, Lev P; Sorokin, Alexey V

2013-12-15

385

The proteolytic YB-1 fragment interacts with DNA repair machinery and enhances survival during DNA damaging stress  

PubMed Central

The Y-box binding protein 1 (YB-1) is a DNA/RNA-binding nucleocytoplasmic shuttling protein whose regulatory effect on many DNA and RNA-dependent events is determined by its localization in the cell. We have shown previously that YB-1 is cleaved by 20S proteasome between E219 and G220, and the truncated N-terminal YB-1 fragment accumulates in the nuclei of cells treated with DNA damaging drugs. We proposed that appearance of truncated YB-1 in the nucleus may predict multiple drug resistance. Here, we compared functional activities of the full-length and truncated YB-1 proteins and showed that the truncated form was more efficient in protecting cells against doxorubicin treatment. Both forms of YB-1 induced changes in expression of various genes without affecting those responsible for drug resistance. Interestingly, although YB-1 cleavage did not significantly affect its DNA binding properties, truncated YB-1 was detected in complexes with Mre11 and Rad50 under genotoxic stress conditions. We conclude that both full-length and truncated YB-1 are capable of protecting cells against DNA damaging agents, and the truncated form may have an additional function in DNA repair. PMID:24107631

Kim, Ekaterina R; Selyutina, Anastasia A; Buldakov, Ilya A; Evdokimova, Valentina; Ovchinnikov, Lev P; Sorokin, Alexey V

2013-01-01

386

Preparation and up-conversion luminescence properties of LaOBr:Yb(3+) /Er(3+) nanofibers via electrospinning.  

PubMed

LaOBr:Yb(3+) /Er(3+) nanofibers were synthesized for the first time by calcinating electrospun PVP/[La(NO3 )3 ?+?Er(NO3 )3 ?+?Yb(NO3 )3 ?+?NH4 Br] composites. The morphology and properties of the final products were investigated in detail using scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), X-ray diffractometry (XRD) and fluorescence spectroscopy. The results indicate that LaOBr:Yb(3+) /Er(3+) nanofibers are tetragonal in structure with a space group of P4/nmm. The diameter of LaOBr:Yb(3+) /Er(3+) nanofibers is?~?147?nm. Under the excitation of a 980-nm diode laser, LaOBr:Yb(3+) /Er(3+) nanofibers emit strong green and red up-conversion emission centering at 519, 541 and 667?nm, ascribed to the (2) H11/2 , (4) S3/2 ???(4) I15/2 and (4) ?F9/2 ???(4) I15/2 energy-level transitions of Er(3+) ions, respectively. The up-conversion luminescent mechanism of LaOBr:Yb(3+) /Er(3+) nanofibers is advanced. Moreover, near-infrared emission of LaOBr:Yb(3+) /Er(3+) nanofibers is obtained under the excitation of a 532-nm laser. The formation mechanism of LaOBr:Yb(3+) /Er(3+) nanofibers is proposed. LaOBr:Yb(3+) /Er(3+) nanofibers could be important up-conversion luminescent materials. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24523144

Ma, Wenwen; Yu, Wensheng; Dong, Xiangting; Wang, Jinxian; Liu, Guixia

2014-11-01

387

Preparation of (Y,Yb)MnO3\\/Y2O3\\/Si (MFIS) Structure by Chemical Solution Deposition Method  

Microsoft Academic Search

(Y,Yb)MnO3 films were prepared on Y2O3-buffered n-type Si(111) substrates using alkoxy-derived precursor solutions and rapid thermal annealing at 750°C in Ar. The (Y,Yb)MnO3 films crystallized to hexagonal phase and had high crystallinity and high degrees of c-axis orientation. The hexagonal (Y,Yb)MnO3 films consisted of uniform grains and had smooth surfaces. The electrical properties of the 200-nm-thick Y0.5Yb0.5MnO3 films crystallized on

Kazuyuki Suzuki; Desheng Fu; Kaori Nishizawa; Takeshi Miki; Kazumi Kato

2003-01-01

388

Direct vibrational structure of protein metal-binding sites from near-infrared Yb3+ vibronic side band spectroscopy.  

PubMed Central

Near-infrared Yb3+ vibronic side band (VSB) spectroscopy is used to obtain structural information of metal binding sites in metalloproteins. This technique provides a selective "IR-like" vibrational spectrum of those ligands chelated to the Yb3+ ion. VSB spectra of various model complexes of Yb3+ representing different ligand types were studied to provide references for the VSB spectra of Yb(3+)-reconstituted metalloproteins. Ca2+ in the calcium-binding protein parvalbumin and Fe3+ in the iron-transporting protein transferrin were replaced with Yb3+. The fluorescence of Yb3+ reconstituted into these two proteins exhibits weak VSBs whose energy shifts, with respect to the main 2F5/2-->2F7/2 Yb3+ electronic transition, represent the vibrational frequencies of the Yb3+ ligands. The chemical nature of the ligands of the Yb3+ in these proteins, as deduced by the observed VSB frequencies, is entirely in agreement with their known crystal structures. For transferrin, replacement of the 12CO3(2-) metal counterion with 13CO3(2-) yielded the expected isotopic shift for the VSBs corresponding to the carbonate vibrational modes. This technique demonstrates enormous potential in elucidating the localized structure of metal binding sites in proteins. PMID:7809143

Roselli, C; Boussac, A; Mattioli, T A

1994-01-01

389

Yb{sup 3+}:BaCaBO{sub 3}F: A potential new self-frequency-doubling laser material  

SciTech Connect

Yb:BaCaBO{sub 3}F (Yb:BCBF) has been investigated as a new laser crystal with potential for self-frequency-doubling. An YB:BCBF laser has been pumped at 912 mm, and a measured slope efficiency of 38% has been obtained for the fundamental laser output at 1034 nm. Single crystal powders of BCBF have been compared with K*P for a relative measure of the second harmonic generating potential, yielding d{sub eff}[BCBF]= (0-66)d{sub eff}[K*P]. The growth, spectroscopy, laser performance, and linear and nonlinear optical properties of YB:BCBF are reported here.

Schaffers, K.I.; DeLoach, L.D.; Ebbers, C.A.; Payne, S.A.

1995-03-09

390

The Castor 120 (TM) motor: Development and qualification testing results  

NASA Technical Reports Server (NTRS)

This paper discusses Thiokol Corporation's static test results for the development and qualification program of the Castor 120(TM) motor. The demonstration program began with a 25,000-pound motor to demonstrate the new technologies and processes that would be used on the larger Castor 120(TM) motor. The Castor 120(TM) motor was designed to be applicable as a first stage, second stage, or strap-on motor. Static test results from the Castor 25 and two Castor 120(TM) motors are discussed in this paper. The results verified the feasibility of tailoring the propellant grain configuration and nozzle throat diameter to meet various customer requirements. The first and second motors were conditioned successfully at ambient temperature and 28 F, respectively, to demonstrate that the design could handle a wide range of environmental launch conditions. Furthermore, the second Castor 120(TM) motor demonstrated a systems tunnel and forward skirt extension to verify flight-ready stage hardware. It is anticipated that the first flight motor will be ready by the fall of 1994.

Hilden, Jack G.; Poirer, Beverly M.

1993-01-01

391

Investigation of EuO Thin Films  

NASA Astrophysics Data System (ADS)

EuO is an interesting material for magnetism and spintronics applications due to its large magneto-optic effects, metal-to-insulator transition, and spin splitting of the conduction band. While bulk EuO was extensively studied as long as 40 years ago, epitaxial and stiochiometric films have been difficult to produce. We report the growth of the magnetic insulator EuO on Yttrium Stabilized Zirconia (YSZ 100) and GaAs (001) by reactive Molecular Beam Epitaxy (MBE). The growth is achieved in a regime in which excess Eu ions are re-evaporated and the ratio of Europium to Oxygen flux is more than one. Magneto-Optic Kerr Effect (MOKE) demonstrates a transition for all films at 69K. Further, we investigate the optical and transport properties of these films as well as temperature dependence.

Swartz, Adrian; Wong, J.; Li, Yan; Ciraldo, J.; Kawakami, R. K.

2010-03-01

392

Anomalous Eu Valence State and Superconductivity in Undoped Eu3Bi2S4F4.  

PubMed

We have synthesized a novel europium bismuth sulfofluoride, Eu3Bi2S4F4, by solid-state reactions in sealed evacuated quartz ampules. The compound crystallizes in a tetragonal lattice (space group I4/mmm, a = 4.0771(1) Å, c = 32.4330(6) Å, and Z = 2), in which CaF2-type Eu3F4 layers and NaCl-like BiS2 bilayers stack alternately along the crystallographic c axis. There are two crystallographically distinct Eu sites, Eu(1) and Eu(2) at the Wyckoff positions 4e and 2a, respectively. Our bond valence sum calculation, based on the refined structural data, indicates that Eu(1) is essentially divalent, while Eu(2) has an average valence of ??+2.64(5). This anomalous Eu valence state is further confirmed and supported, respectively, by Mössbauer and magnetization measurements. The Eu(3+) components donate electrons into the conduction bands that are mainly composed of Bi 6px and 6py states. Consequently, the material itself shows metallic conduction and superconducts at 1.5 K without extrinsic chemical doping. PMID:25314008

Zhai, Hui-Fei; Zhang, Pan; Wu, Si-Qi; He, Chao-Yang; Tang, Zhang-Tu; Jiang, Hao; Sun, Yun-Lei; Bao, Jin-Ke; Nowik, Israel; Felner, Israel; Zeng, Yue-Wu; Li, Yu-Ke; Xu, Xiao-Feng; Tao, Qian; Xu, Zhu-An; Cao, Guang-Han

2014-10-29

393

Magnetic properties of EuTiO3, Eu2TiO4, and Eu3Ti2O7  

Microsoft Academic Search

We have investigated the magnetic properties of EuTiO3 (TN=5.3+\\/-0.2 K), Eu2TiO4 (TC=7.8+\\/-0.2 K), and Eu3Ti2O7 (TC=8+\\/-0.3 K) with the technique of 151Eu Mössbauer spectroscopy. The magnetic exchange constants of these substances were obtained from the spectra using molecular-field theory and were interpreted in terms of 5d admixtures to the 4f wave functions of the Eu2+ ion. In Eu3Ti2O7 we have

Chia-Ling Chien; S. Debenedetti; F. De Barros

1974-01-01

394

A Single EU Seat in the IMF?  

Microsoft Academic Search

AbstractThis article examines the rationale for consolidating EU Member States' position in the International Monetary Fund (IMF). Although a substantial amount of co-ordination already takes place, particularly on issues related to the euro area and the single monetary and exchange rate policy, co-operation between EU countries in the IMF remains a relatively new phenomenon and divergences still prevail. The current

Lorenzo Bini Smaghi

2004-01-01

395

Investigation of Yb:LuAG crystals with high doping concentration  

NASA Astrophysics Data System (ADS)

Two Yb:LuAG (Yb:Lu3Al5O12) plates (thickness 1.05 mm, diameter 3 mm, AR/AR @ 0.9 - 1.1 ?m, Yb-doping c = 15% and 20 %) were prepared for laser experiments. For Yb:LuAG pumping, fibre coupled laser diode operating in pulsed regime was used (fibre core diameter 100 ?m, emission wavelength 968 nm, pulse length 2 ms, repetition rate 10 Hz, maximum energy 40 mJ). The longitudinally pumped Yb:LuAG was placed inside the 148mm long resonator formed by a flat pumping mirror (HR @ 1.0 - 1.1 ?m, HT @ 0.97 ?m) and by a curved output coupler (radius of curvature 150 mm). Set of output couplers with reflectivity R = 70 - 97% @ 1.0-1.1 ?m was used and the output power amplitude was measured in dependence on absorbed pumping power amplitude. It was found that for both samples the output coupler reflectivity had only minor influence on laser output parameters expect emission wavelength (1048nm for R < 90% and otherwise 1031 nm). The sample with lower concentration had a lower threshold (˜ 2.5W for c = 15% and ˜ 3.0W for c = 20%) and higher slope efficiency (˜ 61% for c = 15% and ˜ 50% for c = 20 %). The maximum output power amplitude 6.7W was obtained using Yb:LuAG with c = 20% and R = 92% for pumping power amplitude 14W. Obtained results confirmed the good quality of newly grown highly doped Yb:LuAG crystals.

Šulc, Jan; Hubka, Zbyn?k.; Jelenková, Helena; Nejezchleb, Karel; Škoda, Václav

2013-05-01

396

Hydrological planning studies using Landsat-4 Thematic Mapper (TM)  

NASA Technical Reports Server (NTRS)

NASA, in cooperation with the U.S. Army Corps of Engineers, is evaluating the capabilities of Landsat 4 Thematic Mapper (TM) data for environmental and hydrological applications. Attention is given to the results of studies conducted at the Clinton River Basin in Michigan and the eastern shore of the Chesapeake Bay in Maryland. In the former, the evaluation conducted was for the band combinations: (1) 2, 3, and 4; (2) 3, 4, and 5; (3) 3, 4, 5, and 6; and (4) all seven bands. In the latter case, Multispectral Scanner (MSS) and TM data were classified for combinations (1), (3) and (4). Wetland classification accuracy for the 7-band TM data in this study was found to be 9 percent higher than with MSS data, allowing more reliable and accurate monitoring.

Gervin, J. C.; Mulligan, P. J.; Lu, Y. C.; Marcell, R. F.

1984-01-01

397

Efficient Q-switched Tm:YAG ceramic slab laser.  

PubMed

Characteristics of Tm:YAG ceramic for high efficient 2-?m lasers are analyzed. Efficient diode end-pumped continuous-wave and Q-switched Tm:YAG ceramic lasers are demonstrated. At the absorbed pump power of 53.2W, the maximum continuous wave (cw) output power of 17.2 W around 2016 nm was obtained with the output transmission of 5%. The optical conversion efficiency is 32.3%, corresponding to a slope efficiency of 36.5%. For Q-switched operation, the shortest width of 69 ns was achieved with the pulse repetition frequency of 500 Hz and single pulse energy of 20.4 mJ, which indicates excellent energy storage capability of the Tm:YAG ceramic. PMID:21263612

Zhang, Shuaiyi; Wang, Mingjian; Xu, Lin; Wang, Yan; Tang, Yulong; Cheng, Xiaojin; Chen, Weibiao; Xu, Jianqiu; Jiang, Benxue; Pan, Yubai

2011-01-17

398

Dependence of upconversion emission intensity on Yb3+ concentration in Er3+/Yb3+ co-doped flake shaped Y2(MoO4)3 phosphors  

NASA Astrophysics Data System (ADS)

Yttrium molybdate phosphors with fixed Er3+ and various Yb3+ concentrations were synthesized via a co-precipitation method. The crystal structure and the morphology of the phosphor were characterized by means of x-ray diffraction and field-emission scanning electron microscopy. Under 980 nm excitation, red and green upconversion emissions centred at 660, 553 and 530 nm were observed. Quantitative analyses on the dependence of upconversion emission intensity on the working current of a laser diode (LD) indicated that two-photon processes are responsible for both red and green upconversion emissions in both cases of low and high Yb3+ concentrations. The relationship between the emission intensity ratio of 2H11/2 ?4I15/2 to 4S3/2 ?4I15/2 and the working current of the LD was studied for the samples doped with low and high Yb3+ concentrations. Finally, a set of rate equations was established based on the possible upconversion mechanism, and an empirical formula was proposed to describe the Yb3+ concentration dependence of upconversion emission intensity; the empirical formula fits well with the experimental data.

Lu, Weili; Cheng, Lihong; Zhong, Haiyang; Sun, Jiashi; Wan, Jing; Tian, Yue; Chen, Baojiu

2010-03-01

399

In-Situ Growth of Yb2O3 Layer for Sublimation Suppression for Yb14MnSb11 Thermoelectric Material for Space Power Applications.  

National Technical Information Service (NTIS)

The compound Yb14MnSb11 is a p-type thermoelectric material of interest to the National Aeronautics and Space Administration (NASA) as a candidate replacement for the state-of-the-art Si-Ge used in current radioisotope thermoelectric generators (RTGs). Id...

E. J. Opila, J. A. Nesbitt, M. V. Nathal

2012-01-01

400

Photoluminescence properties of singly doped Tm3+ and co-doped Tm3+/Tb3+ ions in tellurite glasses  

NASA Astrophysics Data System (ADS)

Photoluminescence properties of singly doped Tm3+ and co-doped Tm3+/Tb3+ ions in TZKC glasses with chemical composition of (61.5-x) TeO2 + 25 ZnO + 8 K2O + 5CaO + 0.5Tm2O3 + xTb4O7 (TZKCTm05Tbx; x (in mol%) = 0, 0.5, 1.0, 1.5) have been studied. The experimental oscillator strengths of absorption bands in TZKCTm05 glass were used to determine the host dependent Judd-Ofelt ?2, ?4, ?6 intensity parameters. The effective emission cross-section of 1.8 ?m emission band as a function of wavelength has been deduced by the McCumber's theory. Based on the absorption (?a) and emission cross-sections (?e), the gain co-efficients (G) of 1.8 ?m emission band for various population inversions between the emitting (3F4) and terminating (3H6) levels were evaluated. From the photoluminescence spectra of singly doped Tm3+ and co-doped Tm3+/Tb3+ ions in TZKC glasses, the chromaticity color coordinates (x, y) were estimated.

Sasikala, T.; Rama Moorthy, L.

2014-11-01

401

Luminescence properties and energy transfer in the novel red emitting phosphors Ba2Ln(BO3)2Cl:Sm3+, Eu3+ (Ln=Y, Gd)  

NASA Astrophysics Data System (ADS)

A series of Sm3+/Eu3+ singly and co-doped Ba2Ln(BO3)2Cl (Ln=Y3+, Gd3+) phosphors were prepared via the solid-state method. The XRD results indicate that the as-prepared products keep the monoclinic structure with a P21/m space group of Ba2Ln(BO3)2Cl, which belongs to the isomorphic substitution for Ln3+ sites in the Ba2Yb(BO3)2Cl host. The photoluminescence (PL) spectra demonstrate that Ba2Ln(BO3)2Cl:Sm3+,Eu3+ emits red light centered at 593 nm under the 393 nm excitation which is in good agreement with the emission wavelength from near ultraviolet light-emitting diodes (LEDs). The luminescence decays suggest that the energy transfer from Sm3+ to Eu3+ ions in Ba2Ln(BO3)2Cl:Eu3+, Sm3+ occurs. All results mean that Ba2Ln(BO3)2Cl:Eu3+, Sm3+ phosphors exhibit potential to act as a kind of red phosphor for near ultraviolet white light-emitting diodes (w-LEDs).

Fan, Yan; Hu, Yihua; Chen, Li; Wang, Xiaojuan; Ju, Guifang

2014-10-01

402

RETM5 and RE2TM17 permanent magnets development  

NASA Astrophysics Data System (ADS)

RETM5 and RE2TM17 (RE = rare earth, TM = transition metal) permanent magnets are discussed. The scientific and technological considerations which have guided their development are described to help establish the framework within which most of the work can be integrated and understood. The review limits itself to the technologically significant SmCo5 material and to those processes which have been demonstrated as capable of producing magnets in bulk useful form. Areas covered include phase diagrams, crystal structures, magnetocrystalline anisotropy, coercivity mechanisms, fabrication technologies, processing-microstructure-property interrelationships, and thermal effects related to stability of magnet flux.

Kumar, Kaplesh

1988-03-01

403

Ion-exchanged Tm3+:glass channel waveguide laser.  

PubMed

Continuous wave laser action around 1.9 ?m has been demonstrated in a Tm(3+)-doped germanate glass channel waveguide laser fabricated by ion-exchange. Laser action was observed with an absorbed power threshold of only 44 mW and a slope efficiency of up to 6.8% was achieved. Propagation loss at the lasing wavelength was measured to be 0.3 dB/cm. We believe this to be the first ion-exchanged Tm(3+)-doped glass waveguide laser. PMID:23546272

Choudhary, Amol; Kannan, Pradeesh; Mackenzie, Jacob I; Feng, Xian; Shepherd, David P

2013-04-01

404

Nonparaxial TM and TE beams in free space.  

PubMed

Expressions for the fields of TM and TE laser beams in free space that are rigorous solutions to Maxwell's equations are given in a closed form. The electric and the magnetic fields are both expressed in terms of nonparaxial elegant Laguerre-Gaussian beams that are exact solutions of the Helmholtz equation. These solutions involve well-known functions, such as spherical Bessel and associated Legendre functions. Radially and azimuthally polarized beams of arbitrary order are considered, and the lowest-order radially polarized beam (TM(01) beam) is investigated in detail. PMID:18628798

April, Alexandre

2008-07-15

405

DIME Participants Working on a Legos(TM) Challenge  

NASA Technical Reports Server (NTRS)

Members from all four teams were mixed into pairs to work on a Lego (TM) Challenge device to operate in the portable drop tower demonstrator (background). These two team members are about to try out their LEGO (TM) creation. This was part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

2002-01-01

406

Paramagnetic hyperfine splitting in the 151Eu Mössbauer spectra of CaF2:Eu2+  

PubMed Central

151Eu Mössbauer spectra in zero magnetic field of highly dilute (0.1 mol%) Eu2+ ions in CaF2 showed an almost temperature-independent asymmetrically split pattern, arising from the paramagnetic hyperfine interaction AS. I in a cubic crystal field with slow electron spin relaxation; in a small external magnetic field B of 0.2 T such that g?BB>A an almost symmetrical pattern was observed. Both the spectra with and without external field are well described using the spin Hamiltonian and previous electron paramagnetic resonance data. A more concentrated (2 mol% Eu2+) sample exhibited a strongly broadened symmetrical resonance line due to an increased Eu-Eu spin relaxation rate; in an external magnetic field of 0.2 T the Mössbauer spectra exhibited further broadening and additional magnetic structures due to the reduced relaxation rate. When a large field of 6 T was applied such that g?BB is much larger than the crystal field splitting, a fully resolved hyperfine pattern was observed at 2.5 K, with an effective field at the Eu nuclei of ?33.7 T; at higher temperatures superimposed patterns originating from excited electronic states were observed in the spectra. The present results on the highly dilute CaF2 : 0.1%Eu2+ sample deliver a straightforward explanation for previous observations of a seemingly large dependence of the Eu2+ isomer shift on europium concentration. PMID:19816547

Selling, J.; Bielemeier, B.; Wortmann, G.; Johnson, J. A.; Alp, E. E.; Chen, T.; Brown, D. E.; Johnson, C. E.; Schweizer, S.

2009-01-01

407

Internet: http://ue.eu.int/ E-mail: press.office@consilium.eu.int  

E-print Network

Internet: http://ue.eu.int/ E-mail: press.office@consilium.eu.int For further information call 32 2. A The documents whose references are given in the text are available on the Council's Internet site http by an asterisk; these statements are available on the above mentioned Council Internet site or may be obtained

408

Internet: http://ue.eu.int/ E-mail: press.office@consilium.eu.int  

E-print Network

Internet: http://ue.eu.int/ E-mail: press.office@consilium.eu.int For further information call 32 2. The documents whose references are given in the text are available on the Council's Internet site http by an asterisk; these statements are available on the above mentioned Council Internet site or may be #12;22.IX

409

Internet: http://ue.eu.int/ E-mail: press.office@consilium.eu.int  

E-print Network

Internet: http://ue.eu.int/ E-mail: press.office@consilium.eu.int For further information call 32 2 marks. The documents whose references are given in the text are available on the Council's Internet Internet site or may be obtained from the Press Office. #12;PROVISIONAL VERSION 11.III.2004 6648/04 (Presse

410

EU Support Application Guidance Funding is available to support EU programmes only.  

E-print Network

EU Support ­ Application Guidance Guidelines · Funding is available to support EU programmes only. · Funding will be provided to enable one person from the University of Surrey to attend a meeting in mainland Europe to support bid development activity. · Funding is available to support current members

Doran, Simon J.

411

Facebook and its EU users Applicability of the EU data protection law  

E-print Network

Facebook and its EU users � Applicability of the EU data protection law to US based SNS* Aleksandra (SNS). The analysis will be conducted on the example of Facebook, which is one of the most popular SNS. The goal of the paper is to examine whether European users of Facebook can rely on their national data

Boyer, Edmond

412

The EU as a Framing Actor: Reflections on Media Debates about EU Foreign Policy  

Microsoft Academic Search

AbstractThis article explores the EU's ability to frame the public debates about its external policies. The article begins by broadening the current discussions about the three aspects of actorness legitimacy, attractiveness and recognition by introducing the EU's framing power as a fourth aspect of actorness. Then it proceeds to an empirical analysis of framing, which is based on a discourse

2011-01-01

413

The EU as a Framing Actor: Reflections on Media Debates about EU Foreign Policy  

Microsoft Academic Search

This article explores the EU's ability to frame the public debates about its external policies. The article begins by broadening the current discussions about the three aspects of actorness legitimacy, attractiveness and recognition by introducing the EU's framing power as a fourth aspect of actorness. Then it proceeds to an empirical analysis of framing, which is based on a discourse

2011-01-01

414

Nonlinear losses in photoconductive Yb:YAG laser materials: identification of photocarrier properties by non-steady-state photoEMF  

NASA Astrophysics Data System (ADS)

We report on the investigation of the photocarrier sign and the excitation dynamics in Yb:YAG at 940 nm excitation wavelength by non-steady-state photo-electromotive force technique. Annealed crystals with 25 and 50 % Yb-doping concentration demonstrate hole conductivity, while 80 % Yb:YAG displays electron conductivity. A characteristic relaxation time of approximately 1 ms is observed, which corresponds to the lifetime of the excited Yb3+-ion.

Korneev, N.; Rodriguez-Montero, P.; Wolters, U.; Petermann, K.; Huber, G.

2014-07-01

415

Kinematics at the intersection of the Garlock and Death Valley fault zones, California: Integration of TM data and field studies. LANDSAT TM investigation proposal TM-019  

NASA Technical Reports Server (NTRS)

Processing and interpretation of Thematic Mapper (TM) data, extensive field work, and processing of SPOT data were continued. Results of these analyses led to the testing and rejecting of several of the geologic/tectonic hypotheses concerning the continuation of the Garlock Fault Zone (GFZ). It was determined that the Death Valley Fault Zone (DVFZ) is the major through-going feature, extending at least 60 km SW of the Avawatz Mountains. Two 5 km wide fault zones were identified and characterized in the Soda and Bristol Mountains, forming a continuous zone of NW trending faulting. Geophysical measurements indicate a buried connection between the Avawatz and the Soda Mountains Fault Zone. Future work will involve continued field work and mapping at key locations, further analyses of TM data, and conclusion of the project.

Abrams, Michael; Verosub, Ken

1987-01-01

416

Yb:YAG/Cr:YAG composite crystal with external and microchip resonator  

NASA Astrophysics Data System (ADS)

A compact diode pumped Q-switched lasers, operating at wavelength 1031 nm, were based on the composite crystal Yb:YAG/Cr:YAG. This composite crystal (diameter 3mm) consisted of diffusion bounded 3mm long Yb:YAG (10 at.% Yb/Y) and 1.6mm long Cr:YAG crystal (initial transmission 85% @ 1031 nm). External resonator allowing to tune generated Q-switched pulse parameters or microchip configuration offering the shortest pulses and highest peak power were tested for this device. For longitudinal pumping of Yb:YAG gain medium, fibre coupled (core diameter 200 ?m, NA= 0.22) laser diode, operating at wavelength 968 nm, was used. In the first case, Yb:YAG/Cr:YAG composite crystal was AR-coated and placed inside the 150mm long semihemispherical resonator consisted of a flat pumping mirror (HR @ 1.01 - 1.09 ?m, HT @ 0.97 ?m) and curved output coupler (r = 150mm) with reflectivity 70% @ 1031 nm. Generated pulses with the peak power 23 kW were 17 ns long (FWHM). The highest generated pulse energy was 0.38 mJ. In the second case, the resonator mirrors were deposited directly on the crystal faces. The output coupler reflectivity was 85% @ 1031 nm. In this compact microchip configuration, 140 ps long (FWHM) pulses with energy 0.13mJ and peak power 0.92MW were generated at wavelength 1031 nm.

Šulc, Jan; Koutný, Tomás; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav

2012-03-01

417

Diode pumped tunable lasers based on Tm:CaF2 and Tm:Ho:CaF2 ceramics  

NASA Astrophysics Data System (ADS)

The Tm:CaF2 (4% of TmF3) and Tm:Ho:CaF2 (2% of TmF3, 0.3% of HoF3) ceramics, prepared using hot pressing, and hot formation technique had been used as an active medium of diode pumped mid-infrared tunable laser. A fibre (core diameter 400 ?m, NA = 0.22) coupled laser diode (LIMO, HLU30F400-790) was used to longitudinal pumping. The laser diode was operating in the pulsed regime (6 ms pulse length, 10 Hz repetition rate). The duty-cycle 6% ensures a low thermal load even under the maximum diode pumping power amplitude 25W (ceramics samples were only air-cooled). The laser diode emission wavelength was 786 nm. The 80mm long semi-hemispherical laser resonator consisted of a flat pumping mirror (HR @ 1.85 - 2.15 ?m, HT @ 0.78 ?m) and a curved (r = 150mm) output coupler with a reflectivity of ˜ 98% @ 1.85 - 2.0 ?m for Tm:CaF2 laser or ˜ 99.5% @ 2.0 - 2.15 ?m for Ho:Tm:CaF2. Tuning of the laser was accomplished by using a birefringent filter (single 1.5mm thick quartz plate) placed inside the optical resonator at the Brewster angle. Both samples offered broad and smooth tuning possibilities in mid-IR spectral range and the lasers were continuously tunable over ˜ 100 nm. The obtained Tm:CaF2 tunability ranged from 1892 to 1992nm (the maximum output energy 1.8mJ was reached at 1952nm for absorbed pumping energy 78 mJ). In case of Tm:Ho:CaF2 laser tunability from 2016 to 2111nm was reached (the maximum output energy 1.5mJ was reached at 2083nm for absorbed pumping energy 53 mJ). Both these material are good candidates for a future investigation of high energy, ultra-short, laser pulse generation.

Šulc, Jan; N?mec, Michal; Jelinková, Helena; Doroshenko, Maxim E.; Fedorov, Pavel P.; Osiko, Vyacheslav V.

2014-02-01

418

Tropomyosin isoform 5b is expressed in human erythrocytes: implications of tropomodulin-TM5 or tropomodulin-TM5b complexes in the protofilament and hexagonal organization of membrane skeletons.  

PubMed

The human erythrocyte membrane skeleton consists of hexagonal lattices with junctional complexes containing F-actin protofilaments of approximately 33-37 nm in length. We hypothesize that complexes formed by tropomodulin, a globular capping protein at the pointed end of actin filaments, and tropomyosin (TM), a rod-like molecule of approximately 33-35 nm, may contribute to the formation of protofilaments. We have previously cloned the human tropomodulin complementary DNA and identified human TM isoform 5 (hTM5), a product of the gamma-TM gene, as one of the major TM isoforms in erythrocytes. We now identify TM5b, a product of the alpha-TM gene, to be the second major TM isoform. TM5a, the alternatively spliced isoform of the alpha-TM gene, which differs by 1 exon and has a weaker actin-binding affinity, however, is not present. TM4, encoded by the delta-TM gene, is not present either. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, hTM5 comigrated with the slower TM major species in erythrocyte membranes, and hTM5b comigrated with the faster TM major species. TM5b, like TM5, binds strongly to tropomodulin, more so than other TM isoforms. The 2 major TM isoforms, therefore, share several common features: They have 248 residues, are approximately 33-35 nm long, and have high affinities toward F-actin and tropomodulin. These common features may be the key to the mechanism by which protofilaments are formed. Tropomodulin-TM5 or tropomodulin-TM5b complexes may stabilize F-actin in segments of approximately 33-37 nm during erythroid terminal differentiation and may, therefore, function as a molecular ruler. TM5 and TM5b further define the hexagonal geometry of the skeletal network and allow actin-regulatory functions of TMs to be modulated by tropomodulin. (Blood. 2000;95:1473-1480) PMID:10666227

Sung, L A; Gao, K M; Yee, L J; Temm-Grove, C J; Helfman, D M; Lin, J J; Mehrpouryan, M

2000-02-15

419

The Laryngeal Mask Airway Supreme TM - a single use laryngeal mask airway with an oesophageal vent. A randomised, cross-over study with the Laryngeal Mask Airway ProSeal TM in paralysed, anaesthetised patients  

Microsoft Academic Search

Summary The LMA SupremeTM is a new extraglottic airway device which brings together features of the LMA ProSealTM, FastrachTM and UniqueTM. We test the hypothesis that ease of insertion, oro- pharyngeal leak pressure, fibreoptic position and ease of gastric tube placement differ between the LMA ProSealTM and the LMA SupremeTM in paralysed anesthetised patients. Ninety-three females aged 19-71 years were

S. Eschertzhuber; J. Brimacombe; M. Hohlrieder; C. Keller

2009-01-01

420

Octave-spanning super-continuum from a silica photonic crystal fiber pumped by a 386 MHz Yb:fiber laser  

E-print Network

, mode-locked all-normal dispersion Yb:fiber laser. The laser achieved 45% optical-to-optical efficiency of highly doped Yb fiber has extended the operation of femtose- cond Yb fiber ring lasers beyond a fundamental repetition rate of 500 MHz [1­3]. In [3], a compact and innovative, fiberized pump coupling

421

Alloying and oxidation of in situ produced core-shell Al@Yb nanoalloy particles—An "on-the-fly" study  

NASA Astrophysics Data System (ADS)

Core-shell-structured nanoalloy particles with an Al-dominated interior covered by few Yb monolayers have been fabricated using a vapor-aggregation method involving magnetron sputtering. The radially segregated structure of the Yb-Al nanoparticles has been disclosed by "on-the-fly" photoelectron spectroscopy monitoring of the nanoparticle beam in Yb 4f and Al 2p electron binding energy regions. Both, the binding energy values and the electron microscopy images taken on the deposited nanoparticles, allow estimating their dimensions to be in the 5-10 nm range. The photoelectron spectroscopy results suggest that in these nanoparticles no trivalent Yb - the typical case for the macroscopic Yb-Al alloy - is present. The oxidation of preformed Yb-Al nanoparticles was successfully attempted, leading to the appearance of divalent Yb surface oxide - in contrast to the bulk macroscopic Yb which is trivalent in the oxide. Our results suggest that at intermediate oxygen exposures "sandwich-like" nanoparticles of YbO/Yb/Al were synthesized. At higher O2 exposures, the oxygen seems to penetrate all the way to the Yb-Al interface. The results of the present study have to be considered when photonic applications of Yb-doped garnet nanoparticles are planned.

Zhang, Chaofan; Andersson, Tomas; Mikkelä, Mikko-Heikki; Mârsell, Erik; Björneholm, Olle; Xu, Xiaojun; Tchaplyguine, Maxim; Liu, Zejin

2014-08-01

422

High-power diode-pumped cryogenically-cooled Yb:CaF2 laser with extremely low quantum defect  

E-print Network

High-power diode-pumped cryogenically-cooled Yb:CaF2 laser with extremely low quantum defect S with Yb:CaF2 operating at cryogenic temperature (77 K) leading to extremely low quantum defects of 1-peak power laser with high repetition rate, very interesting laser development at cryogenic temperature has

Boyer, Edmond

423

Solubility study of Yb in n-type skutterudites YbxCo4Sb12 and their enhanced thermoelectric properties  

E-print Network

The solubility of Yb in Yb[subscript x]Co[subscript 4]Sb[subscript 12 was reported to be 0.19 in bulk skutterudites made by melting and slow cooling method. Surprisingly we increased x close to 0.5 by a special sample ...

Yang, J.

424

WD SiliconEdgeTM Lightning Fast and Rugged at a Great Price  

E-print Network

WD SiliconEdgeTM BlueTM Lightning Fast and Rugged at a Great Price Buy with total confidence. WD for the fastest execution. Data Integrity Protection Prevents data loss from unexpected power loss during write

Musicant, Dave

425

Auto exposure EDR Extended Dynamic RangeTM  

E-print Network

WireTM digital interface for local or remote system control of multiple cameras Sensor: 1024 x 1024 pixel, SR measurements. Displacement. Velocity. RPMs. 100 data points per image. English and metric units. Generate: Aluminum housing, epoxy painted. Country of Origin: The United States of America STANDARD ACCESSORIES

426

Improving the Beam Propagation Method for TM Polarization  

E-print Network

error in the coefficient of the leading propagating mode can be observed. Energy conserving corrections equation and all BPM models associated with it have a substantial amplitude error in the coefficientImproving the Beam Propagation Method for TM Polarization Pui Lin Ho and Ya Yan Lu Department

Lu, Ya Yan

427

Editorial Manager(tm) for Climatic Change Manuscript Draft  

E-print Network

Editorial Manager(tm) for Climatic Change Manuscript Draft Manuscript Number: Title: Impacts of El production, exports and imports. We demonstrate that ENSO-related weather shocks affect rice production.ccap@igsnrr.ac.cn Manuscript Click here to download Manuscript: Enso_ClimateChange_July22.doc Click here to view linked

Battisti, David

428

Conductively Cooled Ho:Tm:LuLiF Laser Amplifier  

NASA Technical Reports Server (NTRS)

A conductively-cooled Ho:Tm:LuLiF laser head can amplify 80mJ/340ns probe pulses into 400mJ when the pump pulse energy is close to amplified spontaneous emission (ASE) threshold, 5.6J. For a small signal, the double-pass amplification exceeds 25.

Bai, Yingxin; Yu, Jirong; Trieu, Bo; Petros, M.; Petzar, Paul; Lee, Hyung; Singh, U.

2008-01-01

429

Teaching Engineering Design through Lego[R] Mindstorms[TM  

ERIC Educational Resources Information Center

This paper examines a particular methodology of teaching engineering design to undergraduate engineering students, which relies on Lego[R] Mindstorms[TM]. A number of important issues are addressed, including the timing of the design module within the programme, prior knowledge required and assessment components. The module, which has been running…

Ringwood, J. V.; Monaghan, K.; Maloco, J.

2005-01-01

430

health reform mattersTM alert ATTORNEY ADVERTISINGropesgray.com  

E-print Network

health reform mattersTM alert ATTORNEY ADVERTISINGropesgray.com On March 23, President Obama signed into law the Patient Protection and Affordable Health Care Act (H.R. 3590) (the "Act"), which includes new;and · Discounts(includingrebates). Physician Payment "Sunshine Provisions" Signed into Law as Part of Health Care

Chapman, Michael S.

431

Solvent free triglyceride synthesis using lipozyme TM IM20  

Microsoft Academic Search

Summary The synthesis of triglycerides using LipozymeTM IM-20 (Mucor miehei lipase immobilized on weak anion exchange resins by Novo) is described. Use of pure substrates in stoichiometric amounts in the absence of any organic solvent enables high conversion to be obtained with the addition of molecular sieves to remove water produced by the reaction.

F. Ergan; M. Trani; G. André

1988-01-01

432

Quantum cutting effect in KY3F10:Tm3+  

NASA Astrophysics Data System (ADS)

A cross-relaxation energy-transfer scheme using the 5d state of Tm3+ as the donor and the 4f13 states of Tm3+ as the acceptor is proposed. The scheme is tested in the host KY3F10 doped with several concentrations of Tm3+ as a potential vacuum ultraviolet (VUV) excited blue phosphor of quantum yield greater than unity. Emission and diffuse reflection spectra along with studies of the time evolution of the 5d and 4f populations of Tm3+ in KY3F10 crystals and powders under UV and VUV excitations are reported and analyzed. The results show that the proposed quantum cutting mechanism occurs but the I16 , D12 , and G14 acceptor levels cross relax rapidly to lower-lying levels by an additional cross-relaxation energy transfer and that this effectively quenches the blue emission. Based on the temperature dependence of the spectra, an interesting heat-assisted relaxation process involving intersystem crossing is observed above 300 K.

Beauzamy, Léna; Moine, Bernard; Meltzer, Richard S.; Zhou, Yi; Gredin, Patrick; Jouini, Anis; Kim, Kyoung Jin

2008-11-01

433

Recent developments in the tmLQCD software suite  

E-print Network

We present an overview of recent developments in the tmLQCD software suite. We summarise the features of the code, including actions and operators implemented. In particular, we discuss the optimisation efforts for modern architectures using the Blue Gene/Q system as an example.

Abdou Abdel-Rehim; Florian Burger; Alber Deuzeman; Karl Jansen; Bartosz Kostrzewa; Luigi Scorzato; Carsten Urbach

2013-11-21

434

Design criteria of the Spheral SolarTM cell  

NASA Astrophysics Data System (ADS)

The process sequence for producing 10% efficient Spheral SolarTM cells from upgraded metallurgical grade silicon spheres bonded in aluminum foil was presented at a recent conference.1 Certain design criteria were used to generate the process schedule and these criteria will be described in this paper. Further discussion regarding pilot line equipment and operation will be reserved for a future publication.

Levine, Jules D., Dr.

1992-12-01

435

InsectDirectTM Protein Expression & Purification System  

E-print Network

of the InsectDirectTM System benefit me? Insect GeneJuice Transfection Reagent is a liposomal for- mulation. coli and insect cells · Insect GeneJuice® Transfection Reagent for high-efficiency transfection optimized for maximal transfection efficiency that offers extremely low toxicity to insect cells. It can

Lebendiker, Mario

436

On-line scintillation counting on Meltilex TM basis  

Microsoft Academic Search

A detection system is described for monitoring on-line radioactive process solutions by solid scintillation counting. The system consists of a flow cell with perspex windows coated with the plastic scintillator MeltilexTM. The cell is confined in a chamber welded to a La Calhène container. Thus the detection device is easily attached to, detached from and transported between glove boxes, and

U. Wenzel

1996-01-01

437

Microglassification(TM): a novel technique for protein dehydration.  

PubMed

The dehydration of biologics is commonly employed to achieve solid-dose formulation and enhanced stability during long-term preservation. We have developed a novel process, Microglassification(TM) , which can rapidly and controllably dehydrate protein solutions into solid amorphous microspheres at room temperature. Single bovine serum albumin (BSA) microdroplets were suspended in pentanol or decanol using a micropipette, and the dynamic changes in droplet dissolution were observed in real-time and correlated to protein's water of hydration, medium's water activity, and microsphere protein concentration. Microglassification(TM) was also carried out at bulk scale, and changes in BSA secondary structure were analyzed by Fourier transform infrared spectroscopy and fluorescence spectroscopy; multimer formation was detected by native gel electrophoresis. BSA concentration in the microsphere increased with solvent exposure time and decreasing water activity. Image analysis at single particle and bulk scale showed the formation of solid BSA microspheres with a maximum protein concentration of 1147 ± 32 mg/mL. The native BSA samples were dehydrated to approximately 450 waters per BSA, which is well below monolayer coverage of 1282 waters per BSA. The secondary structure of Microglassified(TM) BSA reverted to native-like conformation upon rehydration with only minor irreversible aggregation (2.7%). Results of the study establish the efficacy of the Microglassification(TM) for the successful dehydration of biologics. PMID:24415208

Aniket; Gaul, David A; Rickard, Deborah L; Needham, David

2014-03-01

438

Elsevier Editorial System(tm) for European Psychiatry Manuscript Draft  

E-print Network

Elsevier Editorial System(tm) for European Psychiatry Manuscript Draft Manuscript Number: EURPSY; Schizophrenia and psychosis; Personality disorders; Psychiatry in Europe; Epidemiology; Social and Cross manuscript, published in "European Psychiatry 2011;26(4):215-23" DOI : 10.1016/j.eurpsy.2010.03.006 #12;Ms

Paris-Sud XI, Université de

439

ORNL/TM-2011/98 Smart Infrared Inspection  

E-print Network

Siekmann Gary Capps Oscar Franzese Mary Beth Lascurain #12;DOCUMENT AVAILABILITY Reports produced after Oscar Franzese Mary Beth Lascurain Date Published: June 2011 Prepared by OAK RIDGE NATIONAL LABORATORYORNL/TM-2011/98 Smart Infrared Inspection System Field Operational Test June 2011 Prepared by Adam

440

"Headsprout Early Reading" [TM]. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

"Headsprout Early Reading"[TM] is an Internet-based supplemental early literacy curriculum consisting of forty 20-minute animated episodes that are designed to teach phonemic awareness, phonics, fluency, vocabulary, and comprehension. The program adapts to a child's responses, providing additional instruction and review if a child does not choose…

What Works Clearinghouse, 2009

2009-01-01

441

Fluency Formula[TM]. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

"Fluency Formula"[TM] is a supplemental curriculum designed to promote reading fluency for first- through sixth-grade students. The program emphasizes automatic recognition of words, decoding accuracy, and oral expressiveness as the foundation for building reading fluency. A daily 10- to 15-minute lesson is delivered in the classroom. Students…

What Works Clearinghouse, 2007

2007-01-01

442

Waterford Early Reading Program [TM]. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

Waterford Early Reading Program[TM] is a software-based curriculum for students in Kindergarten through second grade. The curriculum is designed to promote reading, writing, and typing, incorporating literacy skills such as letter mastery, language stories, spelling, basic writing skills, reading and listening development, and comprehension…

What Works Clearinghouse, 2007

2007-01-01

443

A TE\\/TM modal solution for rectangular hard waveguides  

Microsoft Academic Search

A TE\\/TM modal solution for a longitudinally corrugated rectangular waveguide is developed. These longitudinal corrugations can be used to excite a quasi-TEM wave and form a hard waveguide by correctly choosing the impedance at the guide wall. The correctly chosen impedance is referred to as the hard boundary condition. The modal solution developed here solves the problem of longitudinal corrugations

Larry W. Epp; Daniel J. Hoppe; Daniel T. Kelley

2006-01-01

444

February 2007 NASA/TM-2007-214539  

E-print Network

February 2007 NASA/TM-2007-214539 Preliminary Considerations for Classifying Hazards of Unmanned NASA STI Program Office ... in Profile Since its founding, NASA has been dedicated to the advancement of aeronautics and space science. The NASA Scientific and Technical Information (STI) Program Office plays a key

Maddalon, Jeffrey M.

445

Elsevier Editorial System(tm) for Psychoneuroendocrinology Manuscript Draft  

E-print Network

Elsevier Editorial System(tm) for Psychoneuroendocrinology Manuscript Draft Manuscript Number that in a non-clinical sample of post-pubertal adolescents an endocrine abnormality - a high, flattened diurnal. These results may underscore the need to reconsider existing classification systems which are based

446

A Florida-Friendly LandscapingTM Publication  

E-print Network

the water's edge is called the riparian zone and is often a wetland. Some cities and counties requireA Florida-Friendly LandscapingTM Publication Florida is covered with water. The state boasts over, and the second-longest coastline in the United States. Even if you do not reside on a water- front, the land you

Jawitz, James W.

447

An Excel[TM] Model of a Radioactive Series  

ERIC Educational Resources Information Center

A computer model of the decay of a radioactive series, written in Visual Basic in Excel[TM], is presented. The model is based on the random selection of cells in an array. The results compare well with the theoretical equations. The model is a useful tool in teaching this aspect of radioactivity. (Contains 4 figures.)

Andrews, D. G. H.

2009-01-01

448

Herman Method[TM]. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

The "Herman Method"[TM] teaches reading in small groups of up to three students. The curriculum provides instruction in phonemic awareness, phonics, fluency, vocabulary, and reading comprehension, while also teaching spelling and writing. It contains 20 modules of instruction through a fifth grade level. Each module includes a reading, spelling,…

What Works Clearinghouse, 2010

2010-01-01

449

TM4L: Creating and Browsing Educational Topic Maps  

ERIC Educational Resources Information Center

In this article, we describe TM4L, an environment for building, maintaining and using standards-based, ontology-aware e-learning repositories. It is based on the idea that concept-driven access to learning material implemented as a topic map can bridge the gap between a learner and targeted knowledge. One of the driving goals of this work is to…

Dicheva, Darina; Dichev, Christo

2006-01-01

450

ORNL/TM-2008/105 Cost Methodology for Biomass  

E-print Network

ORNL/TM-2008/105 Cost Methodology for Biomass Feedstocks: Herbaceous Crops and Agricultural Resource and Engineering Systems Environmental Sciences Division COST METHODOLOGY FOR BIOMASS FEESTOCKS ....................................................................................................... 3 2.1.1 Integrated Biomass Supply Analysis and Logistics Model (IBSAL).......................... 6 2

Pennycook, Steve

451

Words Their Way[TM]. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

"Words Their Way"[TM] is an approach to phonics, vocabulary, and spelling instruction for students in kindergarten through high school. The program can be implemented as a core or supplemental curriculum and aims to provide a practical way to study words with students. The purpose of word study (which involves examining, manipulating, comparing,…

What Works Clea