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Sample records for dy ho yb

  1. Magnetic remanence in Yb14-xRExMnSb11 (RE=Tb, Dy, Ho) single crystals

    Science.gov (United States)

    Grebenkemper, Jason H.; Hu, Yufei; Abdusalyamova, M. N.; Makhmudov, F. A.; Kauzlarich, Susan M.

    2016-06-01

    Single crystals of Yb14-xRExMnSb11 (x~0.1, 0.4; RE = Tb, Dy, Ho) have been prepared as a solid solution by Sn flux reactions of the elements. They crystallize in the Ca14AlSb11 structure type in the I41/acd space group. The RE3+preferentially substitutes on the Yb(1) site which is the smallest volume Yb containing polyhedron. In the case of Ho3+, a small amount of Ho3+ also substitutes on the Yb(4) site. The ferromagnetic ordering temperature of Yb14MnSb11 is reduced from 53 K to 41 K as x increases and dependent on the identity of the RE. This is attributed to the reduction in carriers and reduced screening of the Mn2+ local moment. The effective moments, μeff, agree well with the calculated moments assuming the RE substitutes as a trivalent cation. The largest coercive field is observed for RE = Dy (1000 Oe). For the maximum x of Yb14-xRExMnSb11 there are enough carriers for the Ruderman-Kittel-Kasuya-Yosida (RKKY) mechanism of magnetic coupling via conduction electrons to still be valid in describing the ferromagnetic ordering.

  2. Measurement of cross sections producing short-lived nuclei by 14 MeV neutron. Br, Te, Dy, Ho, Yb

    Energy Technology Data Exchange (ETDEWEB)

    Sakane, H.; Matsumoto, T.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan); Iida, T.; Takahashi, A.

    1997-03-01

    Nine neutron activation cross sections producing the nuclei with half-lives between 2 min and 57 min have been measured at energy range between 13.4 and 14.9 MeV for Br, Te, Dy, Ho, Yb. The cross sections of {sup 81}Br(n,p){sup 81m}Se, {sup 128}Te(n,p){sup 128m}Sb, {sup 128}Te(n,{alpha}){sup 125m}Sn, {sup 164}Dy(n,p){sup 164}Tb, {sup 165}Ho(n,{alpha}){sup 162}Tb, {sup 176}Yb(n,p){sup 176}Tm were newly obtained at the six energy points between 13.4-14.9 MeV, although the previous results have been obtained at one energy point. {sup 79}Br(n,2n){sup 78}Br, {sup 164}Dy(n,p){sup 164}Tb are compared with evaluated data of JENDL-3.2. The evaluations for these reactions agree reasonably well with experimental results. The cross sections of (n,p) reaction are compared with systematics by Kasugai et. al. The systematics agrees with experimental results. (author)

  3. Structural and magnetic phase transitions of kagome-like compounds REBaCo{sub 4}O{sub 7} (RE=Dy, Ho, Er, Tm, Yb, Lu)

    Energy Technology Data Exchange (ETDEWEB)

    Markina, M., E-mail: markina@lt.phys.msu.r [Low Temperature Physics Department, Moscow State University, Moscow 119992 (Russian Federation); Vasiliev, A.N. [Low Temperature Physics Department, Moscow State University, Moscow 119992 (Russian Federation); Nakayama, N.; Mizota, T. [Department of Advanced Materials Science and Engineering, Faculty of Engineering, Yamaguchi University, Ube 755-8611 (Japan); Yeda, Y. [Materials Design and Characterization Laboratory, Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581 (Japan)

    2010-05-15

    In a temperature range 5-300 K the specific heat C(T) on a new mixed valence cobalt oxides REBaCo{sub 4}O{sub 7} (RE=Dy, Ho, Er, Tm, Yb, Lu) was investigated. The first-order structural phase transitions from hexagonal P6{sub 3}mc to orthorhombic Cmc{sub 2}1 phase was indicated by a peak-like anomaly in C(T) curves at T{sub S}approx160, 178, 224, and 280 K for RE=Lu, Yb, Tm, and Er correspondingly. The magnetic phase transitions was indicated as the changes of slope on the C(T) curves were found at corresponding temperatures: T{sub N}approx50, 74, 98, and 98 K for RE=Lu, Yb, Tm, and Er, correspondingly.

  4. Pico- and subpicosecond relaxation processes in lanthanide-porphyrin complexes. [Lanthanoids: Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu

    Energy Technology Data Exchange (ETDEWEB)

    Solov' ev, K.N.; Tsvirko, M.P.; Krasauskas, V.V.; Pyatosin, V.E.; Stel' makh, G.F.

    1984-03-01

    Methods of nano- and picosecond absorption spectroscopy and luminescence are used to determine the deactivation rates of ..pi.., ..pi..*-electron states of S/sub 2/, S/sub 1/ and T/sub 1/ in complexes of organic molecules of meso-tetratolylporphyne and tetrabenzoporphyne with trivalent Sm/sup 3 +/, Eu/sup 3 +/, Gd/sup 3 +/, Tb/sup 3 +/, Dy/sup 3 +/, Ho/sup 3 +/, Er/sup 3 +/, Tm/sup 3 +/, Yb/sup 3 +/, Lu/sup 3 +/. Quantitative data on superfast relaxation processes in lanthanide porphyrines are obtained. The function of the metal entral ion is presented in details as the excitation factor in deactivation processes of photoexcitation energy of the systems in question.

  5. Structural and magnetic properties of two branches of the tripod-kagome-lattice family A2R3Sb3O14 (A = Mg, Zn; R = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb)

    Science.gov (United States)

    Dun, Z. L.; Trinh, J.; Lee, M.; Choi, E. S.; Li, K.; Hu, Y. F.; Wang, Y. X.; Blanc, N.; Ramirez, A. P.; Zhou, H. D.

    2017-03-01

    We present a systematic study of the structural and magnetic properties of two branches of the rare-earth tripod-kagome-lattice (TKL) family A2R3Sb3O14 (A = Mg, Zn; R = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb; here, we use abbreviation A-R, as in MgPr for Mg2Pr3Sb3O14 ), which complements our previously reported work on MgDy, MgGd, and MgEr [Z. L. Dun et al., Phys. Rev. Lett. 116, 157201 (2016), 10.1103/PhysRevLett.116.157201]. The present susceptibility (χdc, χac) and specific-heat measurements reveal various magnetic ground states, including the nonmagnetic singlet state for MgPr, ZnPr; long-range orderings (LROs) for MgGd, ZnGd, MgNd, ZnNd, and MgYb; a long-range magnetic charge ordered state for MgDy, ZnDy, and potentially for MgHo; possible spin-glass states for ZnEr, ZnHo; the absence of spin ordering down to 80 mK for MgEr, MgTb, ZnTb, and ZnYb compounds. The ground states observed here bear both similarities as well as striking differences from the states found in the parent pyrochlore systems. In particular, while the TKLs display a greater tendency towards LRO, the lack of LRO in MgHo, MgTb, and ZnTb can be viewed from the standpoint of a balance among spin-spin interactions, anisotropies, and non-Kramers nature of single-ion state. While substituting Zn for Mg changes the chemical pressure, and subtly modifies the interaction energies for compounds with larger R ions, this substitution introduces structural disorder and modifies the ground states for compounds with smaller R ions (Ho, Er, Yb).

  6. Structural and thermoelectric properties of BaRCo{sub 4}O{sub 7} (R = Dy, Ho, Er, Tm, Yb, and Lu)

    Energy Technology Data Exchange (ETDEWEB)

    Wong-Ng, W.; Yan, Y.; Liu, G. [Ceramics Division, NIST, Gaithersburg, Maryland 20899 (United States); Xie, W.; Tritt, T. [Department of Physics, Clemson University, Greensville, South Carolina 29634 (United States); Kaduk, J. [Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Thomas, E. [Air Force Research Laboratory, Wright Pattersen, Ohio 45433 (United States)

    2011-12-01

    The structure and thermoelectric properties of a series of barium lanthanide cobaltites, BaRCo{sub 4}O{sub 7} (R = Dy, Ho, Er, Tm, Yb, and Lu), which were prepared using the spark plasma synthesis technique, have been investigated. The space group of these compounds was re-determined and confirmed to be P31c instead of the reported P6{sub 3}mc. The lattice parameters a and c range from 6.26279(2) Angst to 6.31181(6) Angst , and from 10.22468(6) Angst to 10.24446(15) Angst for R = Lu to Dy, respectively. The crystal structure of BaRCo{sub 4}O{sub 7} is built up from Kagome sheets of CoO{sub 4} tetrahedra, linked by triangular layers of CoO{sub 4} tetrahedra. The values of figure of merit (ZT) of the BaRCo{sub 4}O{sub 7} samples were determined to be around 0.02 at 800 K. X-ray diffraction patterns of these samples have been determined and submitted to the Powder Diffraction File.

  7. Structural Study of a Doubly Ordered Perovskite Family NaLnCoWO6 (Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb): Hybrid Improper Ferroelectricity in Nine New Members.

    Science.gov (United States)

    Zuo, Peng; Colin, Claire V; Klein, Holger; Bordet, Pierre; Suard, Emmanuelle; Elkaim, Erik; Darie, Céline

    2017-07-17

    The compounds of the doubly ordered perovskite family NaLnCoWO6 (Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Yb) were synthesized by solid-state reaction, nine of which (Ln = Y, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Yb) are new phases prepared under high-temperature and high-pressure conditions. Their structural properties were investigated at room temperature by synchrotron X-ray powder diffraction and neutron powder diffraction. All of them crystallize in monoclinic structures, especially the nine new compounds have the polar space group P21 symmetry, as confirmed by second harmonic generation measurements. The P21 polar structures were decomposed and refined in terms of symmetry modes, demonstrating that the polar mode is induced by two nonpolar modes in a manner of Hybrid Improper Ferroelectricity. The amplitudes of these three major modes all increase with decreasing the Ln cation size. The spontaneous ferroelectric polarization is estimated from the neutron diffraction data of three samples (Ln = Y, Tb, and Ho) and can be as large as ∼20 μC/cm(2).

  8. Syntheses, structures, and magnetic properties of a family of heterometallic heptanuclear [Cu5Ln2] (Ln = Y(III), Lu(III), Dy(III), Ho(III), Er(III), and Yb(III)) complexes: observation of SMM behavior for the Dy(III) and Ho(III) analogues.

    Science.gov (United States)

    Chandrasekhar, Vadapalli; Dey, Atanu; Das, Sourav; Rouzières, Mathieu; Clérac, Rodolphe

    2013-03-04

    Sequential reaction of the multisite coordination ligand (LH3) with Cu(OAc)2·H2O, followed by the addition of a rare-earth(III) nitrate salt in the presence of triethylamine, afforded a series of heterometallic heptanuclear complexes containing a [Cu5Ln2] core {Ln = Y(1), Lu(2), Dy(3), Ho(4), Er(5), and Yb(6)}. Single-crystal X-ray crystallography reveals that all the complexes are dicationic species that crystallize with two nitrate anions to compensate the charge. The heptanuclear aggregates in 1-6 are centrosymmetrical complexes, with a hexagonal-like arrangement of six peripheral metal ions (two rare-earth and four copper) around a central Cu(II) situated on a crystallographic inversion center. An all-oxygen environment is found to be present around the rare-earth metal ions, which adopt a distorted square-antiprismatic geometry. Three different Cu(II) sites are present in the heptanuclear complexes: two possess a distorted octahedral coordination sphere while the remaining one displays a distorted square-pyramidal geometry. Detailed static and dynamic magnetic properties of all the complexes have been studied and revealed the single-molecule magnet behavior of the Dy(III) and Ho(III) derivatives.

  9. 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).

    Science.gov (United States)

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

    2012-11-28

    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.

  10. The high-temperature modification of LuAgSn and high-pressure high-temperature experiments on DyAgSn, HoAgSn, and YbAgSn

    Energy Technology Data Exchange (ETDEWEB)

    Heying, B.; Rodewald, U.C.; Hermes, W.; Schappacher, F.M.; Riecken, J.F.; Poettgen, R. [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Heymann, G.; Huppertz, H. [Muenchen Univ. (Germany). Dept. fuer Chemie und Biochemie; Sebastian, C.P. [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany)

    2008-02-15

    The high-temperature modification of LuAgSn was obtained by arc-melting an equiatomic mixture of the elements followed by quenching the melt on a water-cooled copper crucible. HT-LuAgSn crystallizes with the NdPtSb-type structure, space group P6{sub 3}mc: a = 463.5(1), c = 723.2(1) pm, wR2 = 0.0270, 151 F{sup 2}, and 11 variables. The silver and tin atoms build up two-dimensional, puckered [Ag{sub 3}Sn{sub 3}] networks (276 pm Ag-Sn) that are charge-balanced and separated by the lutetium atoms. The Ag-Sn distances between the [Ag{sub 3}Sn{sub 3}] layers of 294 pm are much longer. Single crystals of isotypic DyAgSn (a = 468.3(1), c = 734.4(1) pm, wR2 = 0.0343, 411 F{sup 2}, and 11 variables) and HoAgSn (a = 467.2(1), c = 731.7(2) pm, wR2 = 0.0318, 330 F{sup 2}, and 11 variables) were obtained from arc-melted samples. Under high-pressure (up to 12.2 GPa) and high-temperature (up to 1470 K) conditions, no transitions to a ZrNiAl-related phase have been observed for DyAgSn, HoAgSn, and YbAgSn. HT-TmAgSn shows Curie-Weiss paramagnetism with {mu}{sub eff} = 7.53(1) {mu}{sub B}/Tm atom and {theta}P = -15.0(5) K. No magnetic ordering was evident down to 3 K. HT-LuAgSn is a Pauli paramagnet. Room-temperature {sup 119}Sn Moessbauer spectra of HT-TmAgSn and HT-LuAgSn show singlet resonances with isomer shifts of 1.78(1) and 1.72(1) mm/s, respectively. (orig.)

  11. Growth and spectroscopic investigations of Yb,Ho: YAP and Yb,Ho,Pr:YAP laser crystals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Huili [The Key Laboratory of Photonic Devices and Materials, Anhui Province, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230022 (China); Sun, Dunlu, E-mail: dlsun@aiofm.ac.cn [The Key Laboratory of Photonic Devices and Materials, Anhui Province, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Luo, Jianqiao [The Key Laboratory of Photonic Devices and Materials, Anhui Province, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Cao, Shihao [The Key Laboratory of Photonic Devices and Materials, Anhui Province, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Cheng, Maojie; Zhang, Qingli; Yin, Shaotang [The Key Laboratory of Photonic Devices and Materials, Anhui Province, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China)

    2015-02-15

    Yb,Ho:YAP and Yb,Ho,Pr:YAP laser crystals with high optical quality are successfully grown using the Czochralski method. The absorption coefficient and band width of the two crystals at 970 nm are increased because of the doping of Yb{sup 3+} sensitizer. The three strongest fluorescence peaks of the two crystals are located at approximately 2844, 2853, and 2912 nm, which correspond to the {sup 5}I{sub 6}→{sup 5}I{sub 7} level transitions of Ho{sup 3+} ions. Lifetime measurements indicate that the deactivator Pr{sup 3+} ions can efficiently decrease the lifetime of the lower level {sup 5}I{sub 7} from 8.848 ms to 1.258 ms. Energy-transfer mechanisms are also studied and analyzed, and up-conversion luminescence spectra provide the further evidence that Pr{sup 3+} ions can efficiently depopulate Ho{sup 3+} ions at the {sup 5}I{sub 7} level. All these results show that Yb,Ho,Pr:YAP crystal may be a promising laser medium for realizing 2.8–3.1 μm lasers pumped using a 970 nm laser diode. - Highlights: • New Yb,Ho:YAP and Yb,Ho,Pr:YAP laser crystals are grown by the CZ method. • The absorption and FWHM at 970 nm are increased due to the doping of Yb sensitizer. • The lifetime of lower laser level {sup 5}I{sub 7} decreases from 8.848 to 1.258 ms because of the doping of Pr{sup 3+} deactivator. • The up-conversion luminescence provides the further evidence that Pr{sup 3+} ions can efficiently depopulate Ho{sup 3+} ions at the {sup 5}I{sub 7}. • The Yb,Ho,Pr:YAP crystal may be a promising laser medium for realizing the 2.8–3.1 μm lasers using 970 nm LD.

  12. Lattice dynamics of rare-earth titanates with the structure of pyrochlore R 2Ti2O7 ( R = Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu): Ab initio calculation

    Science.gov (United States)

    Chernyshev, V. A.; Petrov, V. P.; Nikiforov, A. E.

    2015-05-01

    The ab initio calculation has been performed for the crystal structure and the phonon spectrum of titanates with the structure of pyrochlore R 2Ti2O7 ( R = Gd-Lu). The frequencies and types of fundamental vibrations have been found. For R = Tb, Tm, and Yb, this calculation has been carried out for the first time; furthermore, there is no available information on experimental studies of the phonon spectrum for Tm and Yb. The influence of hydrostatic pressure to 35 GPa on the structure, dynamics, and elastic properties of the Gd2Ti2O7 lattice has been investigated. The dependence of the phonon frequencies on the pressure has been obtained. The calculations have predicted that the relative change in the pyrochlore structure volume during compression at pressures to 35 GPa is well described by the third-order Birch-Murnaghan equation of states. The results of the calculations agree with the available experimental data. It has been shown that the structural, dynamic, and elastic properties of the R 2Ti2O7 crystal lattice can be adequately described in the case where the inner shells of the RE ion up to 4 f are replaced by the pseudopotential.

  13. 信息动态%Spectral Analysis of Ho3+ -doped and Ho3+, Yb3+, Er3+ Co-doped Up-conversion Luminescence Borosilicate Glass

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A series of holmium ions doped borosilicate glass, including Ho3+ -doped, Ho3+/ Er3+ -doped, Ho3+/ Y Yb3+-doped and Ho3 Yb3 YEr3+ -doped galss, have been prepared by high-temperature melting. The up-conversion excitation spectra and emission spectra of the samples decrease. The analysis result reveals that both the intensities of excitation spectra and emission spectra were weaken with the Ho3+ concentration. The spectral intensities of Ho3+/Yb3+ -doped borosilicate glass increase with the increase of Ho3+ concentration because of the sensitization of Yb3+. The excitation and emission spectra intensities of Ho3+/Yb3 +/Er3+-doped borosilicate glass are weak, and the reason is the energy transfers from Ho3+ ions to Er3+ ions through energy resonant transfer process. Meanwhile the luminescence mechanism of broadband emission peaked at 550 nm is analyzed.

  14. Efficient ultraviolet-blue to near-infrared downconversion in Bi-Dy-Yb-doped zeolites

    Science.gov (United States)

    Bai, Zhenhua; Fujii, Minoru; Hasegawa, Takashi; Imakita, Kenji; Mizuhata, Minoru; Hayashi, Shinji

    2011-11-01

    Ultraviolet-blue to near-infrared (NIR) downconversion is investigated for the Dy3+-Yb3+ couple in zeolites by steady-state and time-resolved photoluminescence (PL) spectra, and PL excitation spectra. Upon excitation of the 4F9/2 level of Dy3+, NIR quantum cutting could occur through a two-step energy transfer from one Dy3+ ion to two neighbouring Yb3+ ions via an intermediate level. The energy transfer efficiency from the 4F9/2 level is estimated to be 42%, and the intrinsic PL quantum efficiency of Yb3+ emission reaches 54%. The findings may have potential application in enhancing the energy efficiency of silicon-based solar cells.

  15. Spin structure and magnetic frustration in multiferroic RMn2O5 (R=Tb,Ho,Dy)

    NARCIS (Netherlands)

    Blake, G.R.; Chapon, L.C.; Radaelli, P.G.; Park, S.; Hur, N.; Cheong, S-W.; Rodríguez-Carvajal, J.

    2005-01-01

    We have studied the crystal and magnetic structures of the magnetoelectric materials RMn2O5 (R=Tb,Ho,Dy) using neutron diffraction as a function of temperature. All three materials display incommensurate antiferromagnetic ordering below 40 K, becoming commensurate on further cooling. For R=Tb,Ho, a

  16. Evidence for triaxial deformation near N=86 : Collective bands in Dy-152,Dy-153 and Ho-153

    NARCIS (Netherlands)

    Appelbe, DE; Twin, PJ; Beausang, CW; Cullen, DM; Curien, D; Duchene, G; Erturk, S; Finck, C; Haas, B; Paul, ES; Radford, DC; Rigollet, C; Smith, MB; Stezowski, O; Waddington, JC; Wilson, AN

    2002-01-01

    The N=86,87 isotopes of dysprosium and holmium have been investigated using the Eurogam II gamma-ray spectrometer. A new collective rotational band has been observed in Ho-153 and the previously observed nui(13/2) band in Dy-153 has been extended to much higher spin. Comparing these bands and

  17. Therapeutical radiopharmaceuticals based In vivo generator system [{sup 166} Dy] Dy/{sup 166} Ho; Radiofarmacos terapeuticos basados en un sistema de generador In vivo [{sup 166}Dy] Dy/{sup 166}Ho

    Energy Technology Data Exchange (ETDEWEB)

    Ferro F, G.; Garcia S, L.; Monroy G, F.; Tendilla, J.I. [Gerencia de Aplicaciones Nucleares en la Salud, ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Pedraza L, M.; Murphy, C.A. de [Departamento de Medicina Nuclear, Instituto Nacional de Pediatria, Mexico D.F. (Mexico)

    2002-07-01

    At the idea to administer to a patient a molecule containing in it structure a father radionuclide, with a half life enough large which allows to the radiolabelled molecule to take up position specifically in a white tissue and decaying In vivo to the daughter radionuclide with properties potentially therapeutic, it is known as In vivo generator system. In this work the preparation and the preliminary dosimetric valuations of radiopharmaceuticals based In vivo generator system {sup 166} Dy Dy/{sup 166} Ho for applications in radioimmunotherapy, in the treatment of the rheumatoid arthritis and in the bone marrow ablation (m.o.) for candidates patients to bone marrow transplant are presented. (Author)

  18. Co-precipitation synthesis and upconversion luminescence properties of ZrO2:Yb3+-Ho3+

    Indian Academy of Sciences (India)

    Jinsheng Liao; Shaohua Liu; Liling Nie; Suijun Liu; Junxiang Fu

    2015-12-01

    ZrO2:Yb3+-Ho3+ phosphors with different Yb3+ doping concentration have been prepared by coprecipitation method. X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence spectra were used to characterize the properties of ZrO2:Yb3+-Ho3+ phosphors. Different phases of ZrO2 can be obtained by changing the concentration of Yb3+. Under the 980 nm excitation, the sample gives a set of light: strong green (539 nm), weak red (670 nm) and near-infrared (760 nm). The upconversion luminescence is based on two-photon absorption by the energy transfer from the donor (Yb3+) to the acceptor (Ho3+). All the results indicate that ZrO2:Yb3+-Ho3+ phosphors could be a promising biological labelling material.

  19. YellowupconversionluminescenceinHo3+/Yb3+co-dopedGd2Mo3O9phosphor

    Institute of Scientific and Technical Information of China (English)

    孙家跃; 薛兵; 孙广超; 崔殿鹏

    2013-01-01

    The strong yellow upconversion (UC) light emission was observed in Ho3+/Yb3+co-doped Gd2Mo3O9 phosphor under the excitation of 980 nm diode laser. The phosphors were synthesized by the traditional solid-state reaction method. The structures of the samples were characterized by X-ray diffraction (XRD). Under 980 nm excitation, Ho3+/Yb3+co-doped Gd2Mo3O9 exhibited strong yellow UC emission based on the green emission near 541 nm generated by 5F4,5S2→5I8 transition and the strong red emission around 660 nm generated by 5F5→5I8 transition, which assigned to the intra-4f transitions of Ho3+ions. The doping concentrations of Ho3+and Yb3+were determined to be 0.01 mol Ho3+and 0.2 mol Yb3+for the strongest yellow emission. Then the dependence of UC emis-sion intensity on excitation power density showed that the green and red UC emissions were involved in two-photon process. The possible UC mechanisms for the strong yellow emission were also investigated. The result indicated that this material was a promis-ing candidate for the application in the yellow display field.

  20. Intense red upconversion emission of Yb/Tm/Ho triply-doped tellurite glasses.

    Science.gov (United States)

    Zhan, Huan; Zhou, Zhiguang; He, Jianli; Lin, Aoxiang

    2012-05-20

    By conventional melting and quenching methods, 3Yb2O3-0.2Tm2O3-xHo2O3 (wt%, x=0.2~1.2) was doped into an easily fiberized tellurite glass with composition of 78TeO2-10ZnO-12Na2O (mol%) to form YTH-TZN78 glasses. Under 976 nm excitation, the direct sensitizing effect of Yb ions (Yb→Ho) and indirect sensitizing and self-depopulating effects of Tm ions (Yb→Tm→Ho) were found to present intense red upconversion emission at 657 nm (Red, Ho:5F5→5I8) and were responsible for the absence of the usually observed 484 nm emission (Blue, Tm:1G4→3H36). Regardless of the dopant concentration of Ho ions, the intensity of the red emission at 657 nm (Red, Ho:5F5→5I8) is about three times stronger than that of the green one at 543 nm (Green, Ho:5S2→5I8). For this certain red emission at 657 nm, 0.4 wt% Ho2O3-doped YTH-TZN78 glass was found to present the highest emission intensity and is therefore determined as a promising active tellurite glass for red fiber laser development.

  1. The normal and inverse magnetocaloric effect in RCu2 (R=Tb, Dy, Ho, Er) compounds

    Science.gov (United States)

    Zheng, X. Q.; Xu, Z. Y.; Zhang, B.; Hu, F. X.; Shen, B. G.

    2017-01-01

    Orthorhombic polycrystalline RCu2 (R=Tb, Dy, Ho and Er) compounds were synthesized and the magnetic properties and magnetocaloric effect (MCE) were investigated in detail. All of the RCu2 compounds are antiferromagnetic (AFM) ordered. As temperature increases, RCu2 compounds undergo an AFM to AFM transition at Tt and an AFM to paramagnetic (PM) transition at TN. Besides of the normal MCE around TN, large inverse MCE around Tt was found in TbCu2 compound. Under a field change of 0-7 T, the maximal value of inverse MCE is even larger than the value of normal MCE around TN for TbCu2 compound. Considering of the normal and inverse MCE, TbCu2 shows the largest refrigerant capacity among the RCu2 (R=Tb, Dy, Ho and Er) compounds indicating its potential applications in low temperature multistage refrigeration.

  2. Judd-Ofelt analysis, frequency upconversion, and infrared photoluminescence of Ho3+-doped and Ho3+/Yb3+-codoped lead bismuth gallate oxide glasses

    Science.gov (United States)

    Zhou, Bo; Pun, Edwin Yue-Bun; Lin, Hai; Yang, Dianlai; Huang, Lihui

    2009-11-01

    Ho3+-doped and Ho3+/Yb3+-codoped lead bismuth gallate (PBG) oxide glasses were prepared and their spectroscopic properties were investigated. The derived Judd-Ofelt intensity parameters (Ω2=6.81×10-20 cm2, Ω4=2.31×10-20 cm2, and Ω6=0.67×10-20 cm2) indicate a higher asymmetry and stronger covalent environment for Ho3+ sites in PBG glass compared with those in tellurite, fluoride (ZBLAN), and some other lead-contained glasses. Intense frequency upconversion emissions peaking at 547, 662, and 756 nm as well as infrared emissions at 1.20 and 2.05 μm in Ho3+/Yb3+-codoped PBG glass were observed, confirming that energy transfer between Yb3+ and Ho3+ takes place, and a two-phonon-assisted energy transfer from Yb3+ to Ho3+ ions was determined by the calculation using phonon sideband theory. The 1.20 μm emission observed was primarily due to the weak multiphonon deexcitation originated from the small phonon energy of PBG glass (˜535 cm-1). A large product of emission cross-section and measured lifetime (9.93×10-25 cm2 s) was obtained for the 1.20 μm emission and the gain coefficient dependence on wavelength with population inversion rate (P) was performed. The peak emission cross-section for 2.05 μm emission was calculated to be 4.75×10-21 cm2. The relative mechanism of Ho3+-doped and Ho3+/Yb3+-codoped PBG glasses on their spectroscopic properties was also discussed. Our results suggest that Ho3+/Yb3+-doped PBG glasses are a good potential candidate for the frequency upconversion devices and infrared amplifiers/lasers.

  3. Optical properties of Mg2+, Yb3+, and Ho3+ tri-doped LiNbO3 crystals

    Science.gov (United States)

    Dai, Li; Liu, Chun-Rui; Tan, Chao; Yan, Zhe-Hua; Xu, Yu-Heng

    2017-04-01

    A series of LiNbO3 crystals tri-doped with Mg{}2+, Yb{}3+, and Ho{}3+ are grown by the conventional Czochraski technique. The concentrations of Mg{}2+, Yb{}3+, and Ho{}3+ ions in Mg:Yb:Ho:LiNbO3 crystals are measured by using an inductively coupled plasma atomic emission spectrometry. The x-ray diffraction is proposed to determine the lattice constant and analyze the internal structure of the crystal. The light-induced scattering of Mg:Yb:Ho:LiNbO3 crystal is quantitatively described via the threshold effect of incident exposure energy flux. The exposure energy ({E}{{r}}) is calculated to discuss the optical damage resistance ability. The exposure energy of Mg(7 mol):Yb:Ho:LiNbO3 crystal is 709.17 J/cm2, approximately 425 times higher than that of the Mg(1 mol):Yb:Ho:LiNbO3 crystal in magnitude. The blue, red, and very intense green bands of Mg:Yb:Ho:LiNbO3 crystal are observed under the 980-nm laser excitation to evaluate the up-conversion emission properties. The dependence of the emission intensity on pumping power indicates that the up-conversion emission is a two-photon process. The up-conversion emission mechanism is discussed in detail. This study indicates that Mg:Yb:Ho:LiNbO3 crystal can be applied to the fabrication of new multifunctional photoluminescence devices. Project supported by the National Natural Science Foundation of China (Grant No. 51301055), the Youth Science Fund of Heilongjiang Province, China (Grant No. QC2015061), the Special Funds of Harbin Innovation Talents in Science and Technology Research, China (Grant No. 2015RQQXJ045 ), and the Science Funds for the Young Innovative Talents of Harbin University of Science and Technology, China (Grant No. 201501).

  4. Effect of Ho-doping on microstructure and magnetostriction of TbDyFe alloys

    Institute of Scientific and Technical Information of China (English)

    JIANG Minhong; GU Zhengfei; CHENG Gang; LIU Xinyu

    2009-01-01

    Tb0.3Dy0.7HoxFe1.95 (x=0.00, 0.05, 0.10, 0.15, 0.20, 0.35, 0.50, 0.65) quaternary alloys were prepared by arc-melting and followed by annealing. The phases present and structure of the alloys were determined using a D8-Advance X-ray diffractometer. The magnetostriction of the alloys was studied by standard strain gauge technique. The dependence of Ho content on the structure, magnetostriction and density of the alloys was investigated in detail. The research results showed that Ho-doping did not change MgCu2-type cubic Laves structure in Tb0.3Dy0.7Fe1.95. When Ho content x≤0.2, rich rare earth phase presented in the alloys increased and magnetostriction of the alloys reduced evidently with increasing x, but for alloys with x>0.2, the content of rich rare earth phase started to reduce and the magnetostriction increased quickly, especially at low magnetic field in the alloy with x=0.65 due to separation of rich rare earth phases on the surface of the alloy.

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

    CERN Document Server

    Hemmerling, Boerge; Chae, Eunmi; Ravi, Aakash; Doyle, John M

    2013-01-01

    Direct loading of magneto-optical traps from a very slow cryogenic buffer-gas beam of lanthanides is achieved and studied, without the need for laser slowing. A collisionally cooled cryogenic atomic source with average forward velocity of 60-70 m/s and a width of ~70 m/s allows for loading without additional dissipation, unlike oven or supersonic sources. The lanthanides Yb, Tm, Er, and Ho are trapped. Despite the He buffer-gas background, we observe a maximum lifetime of about 80 ms (with Yb). We further show that the addition of a single-frequency slowing laser increases the number of trapped Yb atoms by an order of magnitude, yielding a total of 4.0(2) x 10^8. We study decay to metastable states in all species and report decay rates. Extension of this approach to MOTs of molecules is discussed.

  6. Energy transfer upconversion in Ho sup 3 sup + and Ho sup 3 sup + , Yb sup 3 sup + doped CdF sub 2 crystals

    CERN Document Server

    Zhang Xia; Mary, G

    1998-01-01

    A comparative spectroscopic study for Ho sup 3 sup + and Ho sup 3 sup + , Yb sup 3 sup + doped CdF sub 2 crystals has been realised at liquid nitrogen temperature. The Ho sup 3 sup + single-doped sample shows principally blue emission corresponding to the sup 5 F sub 3-> sup 5 I sub g transition, whereas the Ho sup 3 sup + , Yb sup 3 sup + codoped sample gives rise to a very efficient green emission which is ascribed to the sup 5 F sub 4 , sup 5 S sub 2-> sup 5 I sub g transition. The total integrated upconversion emission intensity (including blue and green emissions) for the codoped crystal is three times more intense than that of the Ho sup 3 sup + doped one, while the ratio for green emission rises to 27. The green emission in the codoped sample results mainly from the Ho sup 3 sup + -Yb sup 3 sup + mixed centre, whereas the blue emission is essentially due to the Ho sup 3 sup + -Ho sup 3 sup + pair. Two energy transfer upconversion mechanisms have been proposed and are discussed in the paper. (author)

  7. Investigation of complexes with bone affinity using the In vivo generator system {sup 166} Dy/{sup 166} Ho; Investigacion de complejos con afinidad osea utilizando el Sistema de Generador in vivo {sup 166} Dy/{sup 166} Ho

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza L, M

    2006-07-01

    The importance of this original research lies in the fact that it has proven that the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system is a stable complex that can be used as a therapeutic radiopharmaceutical. Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. Bone-seeking radiopharmaceuticals such as {sup 166}Ho-DOTMP or {sup 153}Sm-DTMP, have been proposed for delivering ablative radiation doses to marrow in multiple myeloma and other hematological malignancies or have shown excellent results in palliative bone metastasis pain therapy, respectively. As lanthanides have similar chemical characteristics the phosphonate with bone affinity (EDTMP) labeled with Dy/Ho can be used for marrow ablation while causing minimal irradiation to normal organs. This in vivo generator system has not been previously reported. The aim of this research was to label EDTMP (ethylene diamine tetramethylene phosphonate) with {sup 166}Dy/{sup 166}Ho; to evaluate the in vitro and in vivo stability of both {sup 166}Dy-EDTMP and {sup 166}Ho-EDTMP complexes when the daughter {sup 166}Ho is formed as a dysprosium decay product; to determine the bone marrow cytotoxic and genotoxic effect in mice and to evaluate, by histopathology, the myeloablative potential of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system. {sup 166}Dy was obtained by neutron irradiation of enriched {sup 164}Dy{sub 2}O{sub 3} in a TRIGA Mark III reactor. Labeling was carried out in an aqueous phosphate medium at pH 8.0 by addition of {sup 166}DyCl{sub 3} to EDTMP at a molar ratio 1:1.75, with >99 % radiochemical purity, as determined by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). In vitro studies demonstrated that {sup 166}Dy/{sup 166}Ho-EDTMP is unstable after dilution in saline but stable in human serum with no translocation of the daughter nucleus

  8. Preparation of {sup 166} Dy/{sup 166} Ho DTPA-bis biotin as a system of In vivo generator; Preparacion de {sup 166} Dy/{sup 166} Ho DTPA-bis biotina como un sistema de generador In vivo

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez V, M.R

    2003-07-01

    The objective of this work was to synthesize the complex {sup 166} Dy/{sup 166} Ho - diethylen triamine pentaacetic-bis Biotin ({sup 166} Dy/{sup 166} Ho DTPA-bis Biotin) to evaluate its potential as a new radiopharmaceutical in directed radiotherapy. The Dysprosium-166 was obtained for neutron irradiation of {sup 164} Dy{sub 2}0{sub 3} in the TRIGA Mark III reactor. The labelled was carried out in aqueous solution to p H 8.0 for addition of {sup 166} Dy Cl{sub 3} to the diethylen triamine pentaacetic-{alpha}, {omega}-bis Biotin (DTPA-bis Biotin). The radiochemical purity was determined for HPLC and ITLC. The biological integrity of the marked biotin is evaluated by the biological recognition of the avidin for HPLC - molecular exclusion with and without avidin addition. The studies of stability in vitro were made in dilutions of saline solution to 0.9% and with human serum at 37 C incubated 1 and 24 hours. The complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin was obtained with a radiochemical purity of 99.1 {+-} 0.6%. The biological recognition of the complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin for the avidin it doesn't affect the labelling procedure. The studies in vitro demonstrated that the {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin is stable after the dilution in saline solution and in human serum that there is not translocation of the one radionuclide subsequent son to the beta decay of the {sup 166} Dy that could produce the {sup 166} Ho{sup 3+} liberation. The studies of Biodistribution in healthy mice demonstrated that the one complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin have a high renal distribution. In conclusion the radiolabelled biotin in this investigation has the appropriate properties to be used as an In vivo generator system stable for directed radiotherapy. (Author)

  9. Complex magnetism of Ho-Dy-Y-Gd-Tb hexagonal high-entropy alloy

    Science.gov (United States)

    Lužnik, J.; Koželj, P.; Vrtnik, S.; Jelen, A.; Jagličić, Z.; Meden, A.; Feuerbacher, M.; Dolinšek, J.

    2015-12-01

    Rare earth based equimolar Ho-Dy-Y-Gd-Tb hexagonal high-entropy alloy (HEA) is a prototype of an ideal HEA, stabilized by the entropy of mixing at any temperature with random mixing of elements on the hexagonal close-packed lattice. In order to determine intrinsic properties of an ideal HEA characterized by the enormous chemical (substitutional) disorder on a weakly distorted simple lattice, we have performed measurements of its magnetic and electrical response and the specific heat. The results show that the Ho-Dy-Y-Gd-Tb hexagonal HEA exhibits a rich and complex magnetic field-temperature (H ,T ) phase diagram, as a result of competition among the periodic potential arising from the electronic band structure that favors periodic magnetic ordering, the disorder-induced local random potential that favors spin glass-type spin freezing in random directions, the Zeeman interaction with the external field that favors spin alignment along the field direction, and the thermal agitation that opposes any spin ordering. Three characteristic temperature regions were identified in the (H ,T ) phase diagram between room temperature and 2 K. Within the upper temperature region I (roughly between 300 and 75 K), thermal fluctuations average out the effect of local random pinning potential and the spin system behaves as a pure system of compositionally averaged spins, undergoing a thermodynamic phase transition to a long-range ordered helical antiferromagnetic state at the Néel temperature TN=180 K that is a compositional average of the Néel temperatures of pure Tb, Dy, and Ho metals. Region II (between 75 and 20 K) is an intermediate region where the long-range periodic spin order "melts" and the random ordering of spins in the local random potential starts to prevail. Within the low-temperature region III (below 20 K), the spins gradually freeze in a spin glass configuration. The spin glass phase appears to be specific to the rare earths containing hexagonal HEAs, sharing

  10. Neutron diffraction studies of R{sub 2}RhSi{sub 3} (R=Dy, Ho, Er) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Bazela, W.; Penc, B.; Stuesser, N.; Szytula, A.; Wawrzynska, E.; Zygmunt, A

    2004-07-15

    Powder neutron diffraction and magnetic measurements have been carried out on R{sub 2}RhSi{sub 3} (R=Dy, Ho and Er) compounds at low temperatures. These compounds crystallize in a derivative of the hexagonal AlB{sub 2}-type structure and are antiferromagnets with the Neel temperatures equal to: 6.3 K for R=Dy, 5.2 K for R=Ho and 5 K for R=Er. Below these temperatures the magnetic order is described by the propagation vector: k=(0,0,((1)/(2))) for R=Dy, k=(((1)/(2)),0,0) for R=Ho and k=(0,0,0) for R=Er. This magnetic order is stable in the temperature range between 1.5 K and the Neel temperature.

  11. Thermodynamic studies on LnCoO{sub 3}(s) (Ln = Dy, Ho) by solid-state electrochemical cells

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Abhay [Product Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Dash, Smruti [Product Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)], E-mail: smruti@barc.gov.in; Parida, S.C.; Venugopal, V. [Product Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2009-01-05

    Ternary oxides, DyCoO{sub 3}(s) and HoCoO{sub 3}(s) have been synthesized by citrate-nitrate gel combustion method and characterized by X-ray powder diffraction method. The standard molar Gibbs energies of formation of DyCoO{sub 3}(s) and HoCoO{sub 3}(s) have been measured using solid oxide galvanic cell technique employing yttria-stabilized zirconia (YSZ) and calcia-stabilized zirconia (CSZ) as solid electrolyte tubes, respectively. The standard molar Gibbs energies of formation of DyCoO{sub 3}(s) and HoCoO{sub 3}(s) were calculated from the measured e.m.f. data and are given as: {delta}{sub f}G{sub m}{sup o}(DyCoO{sub 3},s,T)kJmol{sup -1}({+-}4)=-1211.3+0.2449{sup *}(TK),(1013K{<=}T{>=}1167K), {delta}{sub f}G{sub m}{sup o}(HCoO{sub 3},s,T)kJmol{sup -1}({+-}4)=-1237.8+0.2590{sup *}(TK).(964K{<=}T{>=}1102K), A set of self consistent thermodynamic functions for LnCoO{sub 3}(s) (Ln = La, Nd, Sm, Eu, Gd, Dy, Ho) has been computed from available experimental data in the literature.

  12. Efficient near-infrared quantum cutting in NaYF4: Ho3+, Yb3+ for solar photovoltaics.

    Science.gov (United States)

    Deng, Kaimo; Gong, Tao; Hu, Lingxun; Wei, Xiantao; Chen, Yonghu; Yin, Min

    2011-01-31

    Quantum cutting converting a ultraviolet photon into two near-infrared photons has been demonstrated by spectroscopic measurements in NaYF4:Ho3+,Yb3+ synthesized by hydrothermal method. Evidence is provided to confirm the occurrence of quantum cutting. Upon excitation of Ho3+ 5G4 level, near-infrared quantum cutting could occur through a two-step resonance energy transfer from Ho3+ to Yb3+ by cross relaxation, with a maximum quantum efficiency of 155.2%. This result reveals the possibility of violet to near-infrared quantum cutting with a quantum efficiency larger than 100% in Ho3+/Yb3+ codoped fluorides, suggesting the possible application in modifying the solar spectrum to enhance the efficiency of silicon solar cells.

  13. Nd3+,Yb3+ and Ho3+ Codoped Oxyfluoride Glass Ceramics with High Efficient Green Upconversion Luminescence

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-Jie; KAWAMOTO Yoji; DAI Shi-Xun; ZHANG Li-Yan; HU Li-Li

    2004-01-01

    @@ New oxyfluoride glasses and glass ceramic codoped with Nd3+, Yb3+ and Ho3+ were prepared. The x-ray diffraction analysis revealed that the heat treatments of the oxyfluoride glasses could cause the precipitation of (Nd3+, Yb3+, Ho3+)-doped fluorite-type crystals. Very strong green up-conversion luminescence due to the Ho3+: (5F4, 5S2) → 5I8 transition under 800-nm excitation was observed in these transparent glass ceramics.The intensity of the green up-conversion luminescence in a 1-mo1% YbF3-containing glass ceramic was found to be about 120 times stronger than that in the precursor oxyfluoride glass. The reason for the highly efficient Ho3+up-conversion luminescence in the oxyfluoride glass ceramics is discussed.

  14. Cytotoxic and genotoxic effect of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system in mice

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza-Lopez, Martha [Departamento de Medicina Nuclear, Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran, Delegacion Tlalpan, Mexico DF 14000 (Mexico); Ferro-Flores, Guillermina [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca, Ocoyoacac, Estado de Mexico, CP 52045 (Mexico); Arteaga de Murphy, Consuelo [Departamento de Medicina Nuclear, Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran, Delegacion Tlalpan, Mexico DF 14000 (Mexico)]. E-mail: consuelo_murphy@yahoo.com.mx; Morales-Ramirez, Pedro [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca, Ocoyoacac, Estado de Mexico, CP 52045 (Mexico); Piedras-Ross, Josefa [Departamento de Medicina Nuclear, Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran, Delegacion Tlalpan, Mexico DF 14000 (Mexico); Murphy-Stack, Eduardo [Hospital Santaelena, Mexico DF (Mexico); Hernandez-Oviedo, Omar [Escuela Superior de Fisica y Matematicas, IPN, Mexico DF (Mexico)

    2004-11-01

    Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. [{sup 166}Dy]Dy/{sup 166}Ho-ethylenediaminetetramethylene phosphonate (EDTMP) forms a stable in vivo generator system with selective skeletal uptake in mice; therefore, it could work as a potential and improved agent for marrow ablation. Induced bone marrow cytotoxicity and genotoxicity are determined by the reduction of reticulocytes (RET) and elevation of micronucleated reticulocyte (MN-RET) in peripheral blood and ablation by bone marrow histological studies. The aim of this study was to determine the bone marrow cytotoxic and genotoxic effect of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system in mice and to evaluate by histopathology its myeloablative potential. Enriched {sup 166}Dy{sub 2}O{sub 3} was irradiated and [{sup 166}Dy]DyCl{sub 3} was added to EDTMP in phosphate buffer (pH 8.0) in a molar ratio of 1:1.75. QC was determined by TLC. Dy-EDTMP complex was prepared the same way with nonirradiated dysprosium oxide. A group of BALB/c mice were intraperitoneally injected with the radiopharmaceutical and two groups of control animals were injected with the cold complex and with 0.9% sodium chloride, respectively. A blood sample was taken at the beginning of the experiments and every 48 h for 12 days postinjection. The animals were sacrificed, organs of interest taken out and the radioactivity determined. The femur was used for histological studies. Flow cytometry analysis was used to quantify the frequency of RET and MN-RET in the blood samples. The MCNP4B Monte Carlo computer code was used for dosimetry calculations. Radiochemical purity was 99% and the mean specific activity was 1.3 MBq/mg. The RET and MN-RET frequency were statistically different in the treatment at the end of the 12-day period demonstrating cytotoxicity and genotoxicity induced by the in vivo generator system. The

  15. Investigation of complexes with bone affinity using the In vivo generator system {sup 166} Dy/{sup 166} Ho; Investigacion de complejos con afinidad osea utilizando el Sistema de Generador in vivo {sup 166} Dy/{sup 166} Ho

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza L, M

    2006-07-01

    The importance of this original research lies in the fact that it has proven that the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system is a stable complex that can be used as a therapeutic radiopharmaceutical. Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. Bone-seeking radiopharmaceuticals such as {sup 166}Ho-DOTMP or {sup 153}Sm-DTMP, have been proposed for delivering ablative radiation doses to marrow in multiple myeloma and other hematological malignancies or have shown excellent results in palliative bone metastasis pain therapy, respectively. As lanthanides have similar chemical characteristics the phosphonate with bone affinity (EDTMP) labeled with Dy/Ho can be used for marrow ablation while causing minimal irradiation to normal organs. This in vivo generator system has not been previously reported. The aim of this research was to label EDTMP (ethylene diamine tetramethylene phosphonate) with {sup 166}Dy/{sup 166}Ho; to evaluate the in vitro and in vivo stability of both {sup 166}Dy-EDTMP and {sup 166}Ho-EDTMP complexes when the daughter {sup 166}Ho is formed as a dysprosium decay product; to determine the bone marrow cytotoxic and genotoxic effect in mice and to evaluate, by histopathology, the myeloablative potential of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system. {sup 166}Dy was obtained by neutron irradiation of enriched {sup 164}Dy{sub 2}O{sub 3} in a TRIGA Mark III reactor. Labeling was carried out in an aqueous phosphate medium at pH 8.0 by addition of {sup 166}DyCl{sub 3} to EDTMP at a molar ratio 1:1.75, with >99 % radiochemical purity, as determined by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). In vitro studies demonstrated that {sup 166}Dy/{sup 166}Ho-EDTMP is unstable after dilution in saline but stable in human serum with no translocation of the daughter nucleus

  16. Magnetic phase diagrams of R2RhIn8 (R = Tb, Dy, Ho, Er and Tm) compounds.

    Science.gov (United States)

    Cermák, P; Kratochvílová, M; Pajskr, K; Javorský, P

    2012-05-23

    We have grown and characterized single crystals of R(2)RhIn(8) (R=Tb, Dy, Ho, Er and Tm) compounds crystallizing in the tetragonal Ho(2)CoGa(8)-type crystal structure. Their magnetic properties were studied by specific heat and magnetization measurements. All the investigated compounds order antiferromagnetically with Néel temperatures of 43.6, 25.1, 10.9, 3.8 and 4.1 K, respectively. Magnetic phase diagrams were constructed.

  17. Magnetization and transport properties of single crystalline RPd2P2 (R=Y, La-Nd, Sm-Ho, Yb)

    Science.gov (United States)

    Drachuck, Gil; Böhmer, Anna E.; Bud'ko, Sergey L.; Canfield, Paul C.

    2016-11-01

    Single crystals of RPd2P2 (R=Y, La-Nd, Sm-Ho, Yb) were grown out of a high temperature solution rich in Pd and P and characterized by room-temperature powder X-ray diffraction, anisotropic temperature- and field-dependent magnetization and temperature-dependent in-plane resistivity measurements. In this series, YPd2P2 and LaPd2P2 YbPd2P2 (with Yb2+) are non-local-moment bearing. Furthermore, YPd2P2 and LaPd2P2 are found to be superconducting with Tc ≃ 0.75 and 0.96 K respectively. CePd2P2 and PrPd2P2 magnetically order at low temperature with a ferromagnetic component along the crystallographic c-axis. The rest of the series manifest low temperature antiferromagnetic ordering. EuPd2P2 has Eu2+ ions and both EuPd2P2 and GdPd2P2 have isotropic paramagnetic susceptibilities consistent with L=0 and J = S = 7/2 and exhibit multiple magnetic transitions. For R=Eu-Dy, there are multiple, T > 1.8 K transitions in zero applied magnetic field and for R=Nd, Eu, Gd, Tb, and Dy there are clear metamagnetic transitions at T=2.0 K for H < 55 kOe. Strong anisotropies arising mostly from crystal electric field (CEF) effects were observed for most magnetic rare earths with L ≠ 0. The experimentally estimated CEF parameters B20 were calculated from the anisotropic paramagnetic θab and θc values and compared to theoretical trends across the rare earth series. The ordering temperatures as well as the polycrystalline averaged paramagnetic Curie-Weiss temperature, θave, were extracted from magnetization and resistivity measurements, and compared to the de-Gennes factor.

  18. Magnetostructural phase transitions and magnetocaloric effect in Tb-Dy-Ho-Co-Al alloys with a Laves phase structure

    Science.gov (United States)

    Tereshina, I. S.; Chzhan, V. B.; Tereshina, E. A.; Khmelevskyi, S.; Burkhanov, G. S.; Ilyushin, A. S.; Paukov, M. A.; Havela, L.; Karpenkov, A. Yu.; Cwik, J.; Koshkid'ko, Yu. S.; Miller, M.; Nenkov, K.; Schultz, L.

    2016-07-01

    The influence of simultaneous substitution within the rare earth (R) and Co sublattices on the structural, magnetic, and magnetocaloric properties of the Laves phase RCo2-type compounds is studied. Main attention is devoted to the studies of the magnetostructural phase transitions and the transition types with respect to the alloy composition. Multicomponent alloys Tbx(Dy0.5Ho0.5)1-xCo2 and Tbx(Dy0.5Ho0.5)1-xCo1.75Al0.25 were prepared with the use of high purity metals. Majority of the Tbx(Dy0.5Ho0.5)1-xCo2 alloys exhibit magnetic transitions of the first-order type and a large magnetocaloric effect. The substitution of Al for Co in Tbx(Dy0.5Ho0.5)1-xCo2 increases the Curie temperature (TC) but changes the transition type from first-to the second-order. The discussion of the physical mechanisms behind the observed phenomena is given on the basis of the first principles electronic-structure calculations taking into account both the atomic disorder and the magnetic disorder effects at finite temperatures. The advantage of Al-containing materials is that sufficiently high magnetocaloric effect values are preserved at T > TC.

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

    Science.gov (United States)

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

    2014-06-01

    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.

  20. White upconversion luminescence in nanocrystalline (Ho,Tm,Yb):KLu(WO{sub 4}){sub 2} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, E. William; Pujol, M. Cinta; Carvajal, Joan J.; Mateos, X.; Aguilo, Magdalena; Diaz, Francesc [Fisica i Cristallografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades c/Marcel.li Domingo, s/n, 43007 Tarragona (Spain); Cascales, Concepcion [Instituto de Ciencia de Materiales de Madrid, CSIC, Calle Sor Juana Ines de la Cruz,Cantoblanco, 28049 Madrid (Spain)

    2011-09-15

    Highly crystalline codoped Ho{sup 3+},Tm{sup 3+},Yb{sup 3+} KLu(WO{sub 4}){sub 2} monoclinic nanocrystals with the C 2/c space group symmetry were synthesized by the modified Pechini method. Powder X-ray diffraction, transmission electron microscopy, upconversion photoluminescence spectra, and kinetic decay were used to characterize the samples. The nanocrystals belonged to the monoclinic phase, with a crystallite size of 30-70 nm. Under 930 nm laser excitation, red, green and blue upconversion emissions were simultaneously observed, due to the energy transfer from the Yb{sup 3+} {sup 2}F{sub 5/2} excited level. The decay times of the emitting states were studied at room temperature to describe the photoluminescence dynamics. The influence of excitation power and calcination conditions on CIE chromaticity coordinates were evaluated. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Study on energy up-conversion in Yb, Ho:YAG crystal

    Institute of Scientific and Technical Information of China (English)

    Lilei Huang(黄莉蕾); Liangneng Wu(邬良能); Yanbin Fu(付晏彬)

    2003-01-01

    Optic parameters, such as the probabilities of radiative and non-radiative transition and the cross-relaxation probability between Yb3+ and Hoa+ ions in Yb,Ho:YAG crystal, are calculated on the basis ofJudd-Ofelt and Dexter theories. The energy up-conversion process is analyzed by solving the transitionrate-equations. The results show that (1) the intensity of the green fluorescence relates to the square ofthe concentration of the active ions; (2) the intensity increases with the concentration of sensitive ions aswell, but the increasing rate goes rather too slow; (3) the efficiency of the energy up-conversion relateswith the speed of the energy up-conversion and the quantum efficiency of the transiting from upper levelto lower level.

  2. Electrical transport and magnetic ordering in 2Ti3Ge4 (=Dy, Ho and Er) compounds

    Indian Academy of Sciences (India)

    R Nirmala; V Sankaranarayanan; K Sethupathi; A V Morozkin; T Geethakumary; Y Hariharan

    2002-05-01

    New 2Ti3Ge4 ( = Dy, Ho and Er) intermetallic compounds have been synthesized and characterized by X-ray diffraction and low temperature ac magnetic susceptibility, electrical resistivity and thermoelectric power measurements were carried out. The compounds crystallize in the parent, Sm5Ge4-type orthorhombic structure (space group Pnma) and lanthanide contraction is observed as one moves along the rare-earth series. The changeover from paramagnetic to antiferromagnetic phase happens at low temperatures and the ordering temperature scales with the de Gennes factor. The electrical resistivity is metallic with a negative curvature above 100 K. Thermopower displays a weak maximum at temperatures less than 50 K signifying the possible phonon and magnon drag effects.

  3. Short-wavelength upconversion emissions in Ho3+/Yb3+ codoped glass ceramic and the optical thermometry behavior.

    Science.gov (United States)

    Xu, Wei; Gao, Xiaoyang; Zheng, Longjiang; Zhang, Zhiguo; Cao, Wenwu

    2012-07-30

    Ho(3+)/Yb(3+) codoped glass ceramic was prepared by melt-quenching and subsequent thermal treatment. Under a 980 nm diode laser excitation, upconversion emissions from Ho(3+) ions centered at 540, 650, and 750 nm were greatly enhanced compared with those in the precursor glass. Especially, the short-wavelength upconversion emissions centered at 360, 385, 418, 445, and 485 nm were successfully obtained in the glass ceramic. An explanation for this phenomenon is given based on the fluorescence decay curve measurements. In addition, an optical temperature sensor based on the blue upconversion emissions from (5)F(2,3)/(3)K(8)→(5)I(8) and (5)F(1)/(5)G(6)→(5)I(8) transitions in Ho(3+)/Yb(3+) codoped glass ceramic has been developed. It was found that by using fluorescence intensity ratio technique, appreciable sensitivity for temperature measurement can be achieved by using the Ho(3+)/Yb(3+) codoped glass ceramic. This result makes the Ho(3+)/Yb(3+) codoped glass ceramic be a promising candidate for sensitive optical temperature sensor with high resolution and good accuracy.

  4. Green upconverted emission enhancement of ZrO{sub 2} : Yb{sup 3+}-Ho{sup 3+} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    SolIs, D; De la Rosa, E [Centro de Investigaciones en Optica, A.P. 1-948, Leon Gto., 37160 (Mexico); Salas, P [Centro de Fisica Aplicada y TecnologIa Avanzada, Universidad Nacional Autonoma de Mexico, A.P. 1-1010, Queretaro 76000 (Mexico); Angeles-Chavez, C, E-mail: elder@cio.m [Instituto Mexicano del Petroleo, Ingenieria Molecular, A.P. 14-805, 07730, Mexico, D.F. (Mexico)

    2009-12-07

    ZrO{sub 2} : Yb{sup 3+}-Ho{sup 3+} nanocrystals with different concentrations of codopants were synthesized with a 0.0082 molar ratio of surfactant Pluronic F-127 using a sol-gel micelle method, and annealed at 1000 {sup 0}C for 5 h. The dominant crystallite phase was tetragonal, with an average crystallite size of 20 nm. The upconverted signal produced by the codoped nanocrystals is an almost pure green emission centred at 540 nm caused by the radiation emitted by the {sup 5}F{sub 4} + {sup 5}S{sub 2} {yields} {sup 5}I{sub 8} relaxation of Ho{sup 3+}. The highest efficiency for the Ho{sup 3+} green emission, with a decay constant ({tau}{sub eff}) of 360 {mu}s, was obtained with a 2/0.001 mol% Yb/Ho composition. This yields a colour coordinate of (0.289, 0.699) with a maximum luminance of 8.7 x 10{sup -3} lm after excitation with a 970 nm continuous wave laser diode. These results can be explained in terms of the energy transfer (ET) from the donor (Yb{sup 3+}) to the acceptor (Ho{sup 3+}). The ET efficiency ({eta}) for this sample was only 5%, although an increase to 42% is possible for larger concentrations of Ho{sup 3+}. Highly concentrated samples have shortened decay times, which cause highly saturated samples to exhibit larger ET efficiency values.

  5. Subsolidus Phase Relations of the CaO-REOx-CuO Systems (RE = Eu, Tb, Dy, Ho, Er, Lu and Sc) at 900 °C in Air

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude

    2016-01-01

    The subsolidus phase relations of the CaO-REOx-CuO systems (RE = Eu, Tb, Dy, Ho, Er, Lu and Sc) were investigated in air at 900 °C. The pseudo-ternary sections with RE = Tb, Dy, Ho, Er and Lu have a similar structure. They have in common with the RE = Eu system a solid solution of Ca0.833−xRExCuO2...... in the other systems at 900 °C in air....

  6. Study of the magnetocaloric properties of the antiferromagnetic compounds RGa2 (R = Ce, Pr, Nd, Dy, Ho and Er).

    Science.gov (United States)

    dos Reis, R D; da Silva, L M; dos Santos, A O; Medina, A M N; Cardoso, L P; Gandra, F G

    2010-12-08

    Magnetocaloric properties of antiferromagnetic RGa(2) (R = Ce, Pr, Nd, Dy, Ho and Er) compounds have been reported. These systems present an antiferromagnetic transition below 15 K and a field induced metamagnetic transition from the antiferromagnetic to ferromagnetic state. Our results show that the character of the magnetic field induced transition along the series affects the magnetocaloric properties. For the compounds with R = Ho, Dy and Er both negative and positive magnetocaloric effect (MCE) were observed above μ(0)ΔH = 2 T where the rate between negative and positive MCE contributions depends on how the magnetic transitions occur in these compounds. The evaluated values of maximum magnetocaloric properties of RGa(2) compounds are similar to other potential magnetic refrigerant materials reported in the literature.

  7. Effect of [Li]/[Nb] ratios on the absorption and up-conversion emission spectra in In:Yb:Ho:LiNbO{sub 3} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Li, E-mail: daili198108@126.com [Applied Science College, Harbin University of Science and Technology, Harbin 150080 (China); State Key Laboratory of Crystal Material, Shandong University, Jinan 250100 (China); Yan, Zhehua; Jiao, Shanshan [Applied Science College, Harbin University of Science and Technology, Harbin 150080 (China); Xu, Chao; Xu, Yuheng [Department of the Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

    2015-09-25

    Highlights: • In:Yb:Ho:LiNbO{sub 3} crystals were grown with various [Li]/[Nb] ratios. • The influence of [Li]/[Nb] ratios on the UV–VIS–NIR is investigated. • This UC process is three-photon process. • In:Yb:Ho:LiNbO{sub 3} crystals (Li/Nb = 1.38) is a promising material for 2 μm wavelength radiation. - Abstract: In:Yb:Ho:LiNbO{sub 3} crystals with high optical quality were grown by the Czochralski method with various ratios of [Li]/[Nb], that is 0.94, 1.05, 1.20 and 1.38 in the melt. The UV–VIS–NIR absorption spectra of In:Yb:Ho:LiNbO{sub 3} crystals were measured. The transition intensity parameters Ω{sub t} (t = 2, 4 and 6), spectroscopic quality factor (X) and the lifetimes of Ho{sup 3+} in In:Yb:Ho:LiNbO{sub 3} crystals were all evaluated by the Judd–Ofelt theory. The spectroscopic quality factor Ω{sub 4}/Ω{sub 6} of In:Yb:Ho:LiNbO{sub 3} crystals with the [Li]/[Nb] ratio of 1.38 was found to be 1.69, which is comparable with those found in widely used Ho{sup 3+} doped crystals. Furthermore, up-conversion emission spectra were determined and analyzed under 980 nm LD excitation in the In:Yb:Ho:LiNbO{sub 3} crystals. The results revealed that In:Yb:Ho:LiNbO{sub 3} crystal with the [Li]/[Nb] ratio of 1.38 is a promising material for 2 μm wavelength radiation.

  8. Effect of Li+ ion sensitization and optical temperature sensing in Gd2O3: Ho3+/Yb3+

    Science.gov (United States)

    Singh, Priyam; Shahi, P. K.; Rai, Anita; Bahadur, A.; Rai, S. B.

    2016-08-01

    Ho3+/Yb3+ codoped Gd2O3 phosphor has been synthesized by solution combustion method. The concentrations of Ho3+ and Yb3+ were optimized to be 0.3 and 2.0 mol% respectively for maximum emission intensity. The effect of Li+ ion co-doping on phase structure and photo luminescence were investigated. It is found that there is no change in phase of the sample due to Li+ ion co-doping. However the Upconversion (UC) and Downshifting (DS) emission show a remarkable enhancement in intensity. It is concluded that, this enhancement in the emission intensity is mainly due to the change in crystal field around the Ho3+ ion and reduction in quenching centers. The optimum doping concentration of Li+ ion was found to be 20 mol%. We have further explored the temperature sensing behavior using the FIR technique. The maximum sensitivity is found to be 0.0092 K-1 at 505 K.

  9. Magnetostructural phase transitions and magnetocaloric effect in Tb-Dy-Ho-Co-Al alloys with a Laves phase structure

    Energy Technology Data Exchange (ETDEWEB)

    Tereshina, I. S., E-mail: irina-tereshina@mail.ru [Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Baikov Institute of Metallurgy and Material Sciences, Russian Academy of Sciences, Moscow 119991 (Russian Federation); International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw 53-421 (Poland); Chzhan, V. B. [Baikov Institute of Metallurgy and Material Sciences, Russian Academy of Sciences, Moscow 119991 (Russian Federation); International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw 53-421 (Poland); National University of Science and Technology “MISIS”, Moscow 119049 (Russian Federation); Tereshina, E. A. [Institute of Physics CAS, Prague 18221 (Czech Republic); Khmelevskyi, S. [Center for Computational Materials Science, IAP, Vienna University of Technology, Vienna A-1040 (Austria); Burkhanov, G. S. [Baikov Institute of Metallurgy and Material Sciences, Russian Academy of Sciences, Moscow 119991 (Russian Federation); Ilyushin, A. S. [Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Complex Research Institute named after Kh. I. Ibragimov, Russian Academy of Sciences, Groznyi 364906 (Russian Federation); Paukov, M. A.; Havela, L. [Faculty of Mathematics and Physics, Charles University, Prague 12116 (Czech Republic); Karpenkov, A. Yu. [Physics Faculty, Tver State University, Tver 170100 (Russian Federation); Department of Physics, Chelyabinsk State University, Chelyabinsk 454001 (Russian Federation); Cwik, J.; Koshkid' ko, Yu. S.; Miller, M. [International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw 53-421 (Poland); Nenkov, K.; Schultz, L. [Leibniz-Institut fur Festkorper- und Werkstoffforschung, Dresden D-01171 (Germany)

    2016-07-07

    The influence of simultaneous substitution within the rare earth (R) and Co sublattices on the structural, magnetic, and magnetocaloric properties of the Laves phase RCo{sub 2}-type compounds is studied. Main attention is devoted to the studies of the magnetostructural phase transitions and the transition types with respect to the alloy composition. Multicomponent alloys Tb{sub x}(Dy{sub 0.5}Ho{sub 0.5}){sub 1−x}Co{sub 2} and Tb{sub x}(Dy{sub 0.5}Ho{sub 0.5}){sub 1−x}Co{sub 1.75}Al{sub 0.25} were prepared with the use of high purity metals. Majority of the Tb{sub x}(Dy{sub 0.5}Ho{sub 0.5}){sub 1−x}Co{sub 2} alloys exhibit magnetic transitions of the first-order type and a large magnetocaloric effect. The substitution of Al for Co in Tb{sub x}(Dy{sub 0.5}Ho{sub 0.5}){sub 1−x}Co{sub 2} increases the Curie temperature (T{sub C}) but changes the transition type from first-to the second-order. The discussion of the physical mechanisms behind the observed phenomena is given on the basis of the first principles electronic-structure calculations taking into account both the atomic disorder and the magnetic disorder effects at finite temperatures. The advantage of Al-containing materials is that sufficiently high magnetocaloric effect values are preserved at T > T{sub C}.

  10. Magnetic-luminescent YbPO4:Er,Dy microspheres designed for tumor theranostics with synergistic effect of photodynamic therapy and chemotherapy.

    Science.gov (United States)

    Wang, Wei; Xu, Dong; Wei, Xiaojun; Chen, Kezheng

    2014-01-01

    In this paper, magnetic and fluorescent bifunctional YbPO4:Er,Dy microspheres were synthesized via a simple solvothermal method. The prepared microspheres exposed to 980 nm near-infrared (NIR) laser light emitted bright upconversion fluorescence (450-570 nm) after calcination at high temperatures (>800°C). Results of magnetic resonance studies demonstrated that the YbPO4:Er,Dy microspheres are more suitable to be used as a transverse relaxation time (negative) contrast magnetic resonance imaging agent. The microspheres successfully entered the human hepatocellular carcinoma cells and presented low toxicity. A well-selected photodynamic therapy (PDT) drug, merocyanine 540 (MC540) with an ultraviolet-visible spectroscopy absorption maximum of 540 nm, was loaded onto the microspheres to obtain YbPO4:Er,Dy-MC540. Since the upconversion fluorescence emitting from the microspheres could be absorbed by MC540 with a small absorption/emission disparity, YbPO4:Er,Dy-MC540 could kill the hepatocellular carcinoma cells via PDT mechanism effectively. In other words, being upconverting particles, the prepared microspheres acted as light transducers in the NIR light-triggered PDT process. A chemotherapy drug, doxorubicin, was further loaded onto YbPO4:Er,Dy-MC540 to achieve enhanced antitumor effect based on synergistic therapeutic efficacy of PDT and chemotherapy. It is expected that the prepared YbPO4:Er,Dy microspheres have applications in tumor theranostics including magnetic-fluorescent bimodal imaging and NIR light-triggered PDT.

  11. Electronic structure and 3d-4f exchange interactions in zircon-type RCrO{sub 4} oxides (R=Dy, Ho and Gd)

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Avijeet, E-mail: avijeet.ray04@gmail.com; Maitra, Tulika [Department of Physics, Indian Institute of Technology, Roorke, Roorkee – 247667, Uttarakhand (India)

    2015-06-24

    Using first principles density functional theory (DFT) calculations within GGA and GGA+U approximations we studied both ferromagnetic (FM) and antiferromagnetic (AFM) phases of zircon type RCrO{sub 4} (R= Dy, Ho, Gd) oxides. We estimated and compared the 3d-4f exchange interaction strengths J between the nearest neighbor R{sup 3+} and Cr{sup 5+} ions for R=Dy, Gd. Our results predict that DyCrO{sub 4}, GdCrO{sub 4} and HoCrO{sub 4} have ferromagnetic ground state which is consistent with experimental observations.

  12. Enhanced frequency upconversion in Ho3+/Yb3+/Li+:YMoO4 nanophosphors for photonic and security ink applications

    Science.gov (United States)

    Mondal, Manisha; Kumar Rai, Vineet; Srivastava, Chandan; Sarkar, Suman; Akash, R.

    2016-12-01

    The YMoO4 nanophosphors codoped with Ho3+/Yb3+/Li+ ions synthesized by the chemical coprecipitation method have been structurally characterized by using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and Transmission Electron Microscopy (TEM) techniques. The TEM bright field imaging shows that the developed nanophosphors are crystalline in nature with particle size ˜45 nm. The upconversion (UC) emission spectra upon excitation at 980 nm of the nanophosphors at low pump power (energy transfer from the Yb3+ to Ho3+ ions and modified the local crystal field developed around the rare earth ions. A higher value of the slope (i.e., n ˜ 6.38) for broad band emission within the 944 mW-1200 mW pump power region in the Ho3+-Yb3+-Li+ codoped nanophosphors is found to be due to the involvement of the photon avalanche population process but it is not related to the black body radiation. The intense peak at ˜564 nm and ˜648 nm for the broad band emission is attributed to the charge transfer luminescence of codoped nanophosphors, which is related to the oxygen ion present in the MoO4 group and Yb3+ ion. The observations described in this paper may be of significant interest for developing the visible upconverters, security ink, and novel devices for displays in the low and high pump power region.

  13. Genotoxic and cytotoxic damage by the therapeutic radiopharmaceutical [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP as in vivo generator system; Dano genotoxico y citotoxico por el radiofarmaco terpeutico [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP como sistema de generador in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza L, M.; Piedras R, J. [Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran. Vasco. de Quiroga 15, 14000 Mexico D.F. (Mexico); Ferro F, G.; Morales R, P. [ININ, Km. 36.5 Carretera Mexico-Toluca, Ocoyoacac, 52045 Estado de Mexico (Mexico); Murphy S, E. [Hospital Santaelena, Mexico D.F. (Mexico); Hernandez O, O. [Escuela Superior de Fisica y Matematicas, IPN, Mexico D.F. (Mexico)

    2005-07-01

    In patients with leukemias and multiple myeloma, the cure can be obtained to inclination of a bone marrow transplant (m.o.), for that which one is used a combination of external radiotherapy and chemotherapy with the consequent toxicity to healthy organs. The complex [{sup 166}Dy]Dy/{sup 166}Ho-ethylenediaminetetramethylenephosphonate ([{sup 166}Dy]Dy/{sup 166}Ho-EDTMP) it forms a generator system in vivo stable with bony selective likeness in mice therefore, this it could work as a therapeutic radiopharmaceutical for bone marrow ablation. The objective of this original work was to determine the genotoxic and cytotoxic damage produced by the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP like a generator system in vivo by means of the reticulocytes reduction (RET) and micronucleus elevation in reticulocytes (RET-MN) in peripheral blood and to evaluate its myeloablative potential for histopathologic studies. It was irradiated {sup 166}Dy{sub 2}O{sub 3} enriched and it was add in form {sup 166}DyCI{sub 3} to the EDTMP in a softening media of phosphates (pH 8), the optimal molar relationship {sup 166}Dy: EDTMP was 1.7:1 and the radiochemical purity was evaluated by ITLC. The Dy:EDTMP complexes, non radioactive, its were prepared in the same way with non irradiated dysprosium oxide. A group of BALB/c mice was injected intraperitoneally with the radiopharmaceutical and two groups of control mice were injected with the non radioactive complex and with sodium chloride 0.9% respectively. Before injecting each one of the solutions it was take a basal sample of peripheral blood of the mouse tail and each 48 h post-injection during 12 d. The animals were sacrificed to obtain the organs of interest and to determine the radioactivity in each one. The femur was used for the histopathologic studies. The quantification of the frequency of RET and RET-MN was carried out by flow cytometry of the sanguine samples and the Monte Carlo code MCNP4B for the dosimetry calculations was used. The

  14. Hydrothermal Synthesis and Up-Conversion Luminescence of Yb3+/Ho3+ Co-doped Y6WO12 Nanocrystals

    Science.gov (United States)

    Rao, Weifeng; Zhu, Qiansheng; Ren, Qiang; Wu, Chenchen; Miao, Juhong

    2017-08-01

    Yb3+/Ho3+ co-doped Y6WO12 nanocrystals with different concentrations of Ho3+ ions have been synthesized through a facile hydrothermal method followed by a subsequent heat treatment. The nanostructures, morphologies, and up-conversion luminescent properties of the as-prepared Y6WO12:Yb3+/Ho3+ nanocrystals were investigated by powder x-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence spectra. XRD results indicate that all the diffraction peaks of the samples match well with the cubic phase of Y6WO12. SEM images demonstrate that the samples consist of spherical-like nanoparticles ranging in size from about 30 nm to 50 nm, which increases slightly with the increase of sintering temperature. Under the excitation of a 980 nm diode laser, the as-prepared nanocrystals show bight red and green luminescence, which is attributed to the transition of 5F5 → 5I8 and 5F4, 5S2 → 5I8 of Ho3+, respectively. With the elevation of the heat treatment temperature from 700°C to 900°C, the up-conversion emission intensity goes up significantly. Additionally, the decay lifetimes data follow a bi-exponential nature. Both the emission intensity (red and green) and their corresponding decay lifetimes increase with increasing Ho3+ concentration, maximizing at 1.0 mol.%, and then decrease, which is mainly attributed to the concentration quenching effect.

  15. Upconversion white-light emission in Ho3+/Yb3+/Tm3+ tridoped LiNbO3 single crystal.

    Science.gov (United States)

    Xing, Lili; Wu, Xiaohong; Wang, Rui; Xu, Wei; Qian, Yannan

    2012-09-01

    Ho3+/Yb3+/Tm3+ tridoped LiNbO3 single crystal exhibiting intense upconversion white light under 980 nm excitation has been successfully fabricated by the Czochralski method. The tridoped LiNbO3 single crystal offers power dependent color tuning properties by simply changing excitation power. Efficient three-photon blue upconversion emission and two-photon green and red upconversion emissions have been observed. In addition, the red emission of Ho3+ originates dominantly from the nonradiative decay of green emission. The LiNbO3 with upconversion white light will be a potential laser candidate material.

  16. Strong broad green UV-excited photoluminescence in rare earth (RE = Ce, Eu, Dy, Er, Yb) doped barium zirconate

    Energy Technology Data Exchange (ETDEWEB)

    Borja-Urby, R. [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A. C., Leon, Gto. 37150 (Mexico); Diaz-Torres, L.A., E-mail: ditlacio@cio.mx [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A. C., Leon, Gto. 37150 (Mexico); Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, A.P. 1-1010, Queretaro, Qro. 76000 (Mexico); Angeles-Chavez, C. [Instituto Mexicano del Petroleo, Ciudad de Mexico, D. F. 07730 (Mexico); Meza, O. [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A. C., Leon, Gto. 37150 (Mexico)

    2011-10-25

    Highlights: > Trivalent rare earth (RE) substitution on Zr{sup 4+} sites in BaZrO{sub 3} lead to band gap narrowing. > RE substitution lead to enhanced blue-green intrinsic emission of nanocrystalline BaZrO{sub 3} > Blue-green hue of BaZrO3:RE depends on RE dopant and excitation UV wavelength > BaZrO3: Dy{sup 3+} PL chromatic coordinates correspond to pure white color coordinates of CIE 1931 model - Abstract: The wet synthesis hydrothermal method at 100 deg. C was used to elaborate barium zirconate (BaZrO{sub 3}) unpurified with 0.5 mol% of different rare earth ions (RE = Yb, Er, Dy, Eu, Ce). Morphological, structural and UV-photoluminescence properties depend on the substituted rare earth ionic radii. While the crystalline structure of RE doped BaZrO{sub 3} remains as a cubic perovskite for all substituted RE ions, its band gap changes between 4.65 and 4.93 eV. Under 267 nm excitation the intrinsic green photoluminescence of the as synthesized BaZrO{sub 3}: RE samples is considerably improved by the substitution on RE ions. For 1000 deg. C annealed samples, under 267 nm, the photoluminescence is dominated by the intrinsic BZO emission. It is interesting to notice that Dy{sup 3+}, Er{sup 3+} and Yb{sup 3+} doped samples present whitish emissions that might be useful for white light generation under 267 nm excitation. CIE color coordinates are reported for all samples.

  17. Preparation and Magnetostriction of Tb0.22Dy0.48HO0.35Fe2 Alloys

    Institute of Scientific and Technical Information of China (English)

    Jiang Minhong

    2007-01-01

    Tb0.22Dy0.48Ho0.35Fe2 quaternary alloys are prepared by melting-top casting-annealing process. X-ray diffraction reveals that the alloy is single phase polycrystalline alloy with MgCu2 type cubic Laves phase structure, and (511) preferred orientation occurs in its. The magnetostriction measurements are carried out at room temperature using standard strain gauge technique in magnetic fields up to 400kA·m-1. The results show that when the magnetic field, H, is 90kA·m-1, the magnetostriction, λ ,of Tb0.22Dy0.48Ho0.35Fe2 quaternary alloys is 260×10-6, and when the H is 210kA·m-1, the λ is 438×10-6. When the H is 400kA·m-1, the λ is up to the saturation value, 538×10-6. As compared with TbDyFe ternary alloys, the λ of the quaternary alloy is significantly higher when the H is less than or equal to 210kA·m-1. When the H is 120kA·m-1,the λ of the alloy is 333×10-6,70×10-6 more than the ternary alloy. Research results and mechanism are discussed.

  18. Superconducting Dy1-x(Gd,Yb)xBa2Cu3O7-δ thin films made by Chemical Solution Deposition

    DEFF Research Database (Denmark)

    Opata, Yuri Aparecido; Wulff, Anders Christian; Hansen, Jørn Otto Bindslev

    2016-01-01

    Dy1-x(Gd or Yb)xBa2Cu3O7-δ samples were prepared using chemical solution deposition (CSD), based on trifluoroacetate metal-organic decomposition (MOD) methods. X-ray diffraction results demonstrated the formation of the RE123 superconducting phase with a strong in-plane and out-of-plane texture. c...

  19. Enhanced 2-5 μm emission in Ho3+/Yb3+ codoped halide modified transparent tellurite glasses

    Science.gov (United States)

    Zhang, Wenjun; Lin, Jian; Jia, Yujie; Zhang, Shuo; Zhao, Junhong; Sun, Guangyao; Ye, Song; Ren, Junjiang; Rong, Liang

    2015-01-01

    Ho3+/Yb3+ codoped TeO2-WO3-ZnO-ZnX2(X = F, Cl) glasses were prepared by melt-quenching method. The absorption spectra, transmittance spectra, X-ray diffraction (XRD) curves, Raman spectra and mid-infrared fluorescence spectra were measured, along with the Judd-Ofelt intensity parameters, stimulated emission and absorption cross-sections were calculated to evaluate the effects of halide amount of the spectroscopic properties. It is shown that the introduction of an appropriate amount of halide can further improve the mid-infrared fluorescence intensity through an enhanced phonon-assisted energy transfer between Ho3+/Yb3+ ions and the energy transfer mechanisms are investigated quantitatively in detail by calculating energy transfer microparameters and phonon contribution ratios. The results indicate that this kind of glasses is a promising material for mid-infrared optical fiber.

  20. Syntheses, Structure, Magnetism, and Optical Properties of the Partial Ordered Quaternary Interlanthanide Sulfides PrLnYb2S6 (Ln = Tb, Dy)

    Energy Technology Data Exchange (ETDEWEB)

    Booth, Corwin H; Jin, Geng Bang; Choi, Eun Sang; Guertin, Robert P.; Brooks, James S.; Bray, Travis H.; Booth, Corwin H.; Albrecht-Schmitt, Thomas E.

    2008-01-11

    Dark red single crystals of PrLnYb{sub 2}S{sub 6} (Ln = Pr/Yb, Tb, Dy) have been synthesized through the reaction of elemental rare earth metals and S using a Sb{sub 2}S{sub 3} flux at 1000 C. These isotypic compounds adopt the F-Ln{sub 2}S3 three-dimensional open channel structure type. Eight-coordinate Pr{sup 3+} ions sit in the channels, which are constructed from three different edge-shared double chains running down the b axis, which contain Yb(1)S{sub 6} octahedra, Yb(2)S{sub 6}, octahedra and LnS{sub 7} monocapped trigonal prisms, respectively. Each double chain connects to four other neighbors by sharing vertices and edges. Considerable disordering in Ln positions was observed in single X-ray diffraction experiments only in the case of Pr/Yb. Least square refinements gave rise to the formulas of Pr{sub 1.34}Yb{sub 2.66}S{sub 6}, of PrTbYb{sub 2}S{sub 6}, and PrDyYb{sub 2}S{sub 6}, which are confirmed by the elemental analysis and magnetic susceptibility measurements. Pr1.34Yb2.66S{sub 6}, PrTbYb{sub 2}S{sub 6} and PrDyYb{sub 2}S{sub 6} are paramagnetic down to 2 K without any indications of long range magnetic ordering. The optical transitions for Pr{sub 1.34}Yb{sub 2.66}S{sub 6}, PrTbYb{sub 2}S{sub 6}, and PrDyYb{sub 2}S{sub 6} are at approximately 1.6 eV. Crystallographic data: Pr{sub 1.34}Yb{sub 2.66}S{sub 6}, monoclinic, space group P2{sub 1}/m, a = 10.960(2), b = 3.9501(8), c = 11.220(2) {angstrom}, {beta} = 108.545(3), V = 460.54(16), Z = 2; PrTbYb{sub 2}S{sub 6}, monoclinic, space group P2{sub 1}/m, a = 10.9496(10), b = 3.9429(4), c = 11.2206(10) {angstrom}, {beta} = 108.525(2), V = 459.33(7), Z = 2; PrDyYb{sub 2}S{sub 6}, monoclinic, space group P2{sub 1}/m, a = 10.9384(10), b = 3.9398(4), c = 11.2037(10) {angstrom}, {beta} = 108.612(2), V = 457.57(7), Z = 2.

  1. Magnetic properties of R/sub 3/Rh/sub 2/ compounds with R = Gd, Tb, Dy, Ho and Er

    Energy Technology Data Exchange (ETDEWEB)

    Gignoux, D. (Centre National de la Recherche Scientifique, 38 - Grenoble (France). Lab. Louis Neel); Gomez-Sal, J.C.; Aramburu-Zabala, J.A. (Santander Univ. (Spain). Facultad de Ciencias); Paccard, D. (Universite de Savoie, 74 - Annecy-le-Vieux (France). Lab. Structure de la Matiere)

    1984-04-01

    Bulk magnetic measurements performed on polycrystalline samples of the tetragonal compounds R/sub 3/Rh/sub 2/ with R = Gd, Tb, Dy, Ho and Er are presented. All the compounds are ferromagnetic at low temperature. However in Tb/sub 3/Rh/sub 2/ an antiferromagnetic behaviour is observed between 14 and 24 K. In Gd/sub 3/Rh/sub 2/, where the magnetocrystalline anisotropy must be negligible, it seems that the magnetic structure is not collinear. In the other compounds the observed properties essentially result from indirect exchange interactions and crystal field effects acting on the rare earth ions which lie in low symmetry sites.

  2. Thermoelastic properties of ScB2, TiB2, YB4 and HoB4

    DEFF Research Database (Denmark)

    Waskowska, A.; Gerward, L.; Staun Olsen, J.

    2011-01-01

    modulus 180-200GPa), while TiB2 may be classified as superhard (bulk modulus about 260GPa). We report here first experimental and theoretical determinations of the bulk modulus for HoB4 (195(5) and 198.2GPa, respectively), and first experimental values of the bulk modulus for ScB2 (196(2)GPa) and YB4 (185......(4)GPa). No pressure-induced phase transformations are observed in any of the above borides up to about 20GPa. A continuous temperature-driven orthorhombic distortion is observed for HoB4 below 285K. Values of the thermal expansion coefficient are reported for ScB2 and HoB4 at 293, 200 and 100K...

  3. Infrared-to-green upconversion luminescence and mechanism of Ho3+, Nd3+ and Yb3+ ions in oxyfluoride glass ceramics

    Institute of Scientific and Technical Information of China (English)

    Zhang Jun-Jie; Kawamoto Yoji; Dai Shi-Xun

    2004-01-01

    New oxyfluoride glasses and glass ceramics co-doped with Nd3+, Yb3+ and Ho3+ were prepared. The upconversion of infrared radiation into green fluorescence has been studied for Nd3+, Yb3+ and Ho3+ in the transparent oxyfluoride glass ceramics. At room temperature very strong green upconversion luminescence due to the Ho3+: (5F4, 5S2) →5I8transition under 800 nm excitation was observed in the glass ceramics. The intensity of the green upconversion luminescence in a 1mol% YbF3-containing glass ceramic was found to be about 120 times stronger than that in the precursor oxyfluoride glass. The reason for the highly efficient Ho3+ upconversion luminescence in the oxyfluoride glass ceramics is discussed. The upconversion mechanism is also investigated.

  4. Estimation on Magnetic Refrigeration Material (Gd1-xREx)5Si4(RE=Dy,Ho)

    Institute of Scientific and Technical Information of China (English)

    Wei WU; Zai FENG; Lijun GUO

    2006-01-01

    A systematic (Gd1-xREx)5Si4 (RE=Dy, Ho) alloys are investigated to estimate their magnetocaloric effect.The Curie points of (Gd1-xREx)Si4 alloys can tunable from 266 K to 336 K when RE=Dy, Ho; x=0~0.35 and 0~0.15, respectively, and decrease nearly linearly with increasing x. These alloys keep orthorhombic structures Ge5Sm4 and exhibit second order transition when they experience in a change magnetic field at about Curie when magnetic field changes 0~2 T. The adiabatic temperatures changes (△Tad) of these alloys at Curie points are larger than 1 K in a field change 0~1.4 T, the curve of △Tad is wide as that of Gd. The relative cooling power is about 0.8~0.9 J/cm3 when field changes 0~2 T, 55% of that of Gd. Comparing with Gd5(Si1-xGex)4, these alloys do not contain expensive element Ge, so that their cost are lower than the former. Because they could work at temperature region 260~340 K due to their Curie points can be tuned, which is an advantage comparing with Gd, these alloys are potential magnetic refrigerants working in a magnetic refrigerator with a low magnetic field at room temperatures.

  5. Crystal field effects in the intermetallic R Ni3Ga9 (R =Tb , Dy, Ho, and Er) compounds

    Science.gov (United States)

    Silva, L. S.; Mercena, S. G.; Garcia, D. J.; Bittar, E. M.; Jesus, C. B. R.; Pagliuso, P. G.; Lora-Serrano, R.; Meneses, C. T.; Duque, J. G. S.

    2017-04-01

    In this paper, we report temperature-dependent magnetic susceptibility, electrical resistivity, and heat-capacity experiments in the family of intermetallic compounds R Ni3Ga9 (R = Tb, Dy, Ho, and Er). Single-crystalline samples were grown using Ga self-flux method. These materials crystallize in a trigonal ErNi3Al9 -type structure with space group R 32 . They all order antiferromagnetically with TNK . The anisotropic magnetic susceptibility presents large values of the ratio χeasy/χhard indicating strong crystalline electric-field (CEF) effects. The evolution of the crystal-field scheme for each R was analyzed in detail by using a spin model including anisotropic nearest-neighbor Ruderman-Kittel-Kasuya-Yosida interaction and the trigonal CEF Hamiltonian. Our analysis allows one to understand the distinct direction of the ordered moments along the series—the Tb-, Dy-, and Ho-based compounds have the ordered magnetic moments in the easy ab plane and the Er sample magnetization easy axis is along the c ̂ direction.

  6. Tunable multicolor and white-light upconversion luminescence in Yb3+/Tm3+/Ho3+ tri-doped NaYF4 micro-crystals.

    Science.gov (United States)

    Lin, Hao; Xu, Dekang; Teng, Dongdong; Yang, Shenghong; Zhang, Yueli

    2015-09-01

    NaYF4 micro-crystals with various concentrations of Yb(3+) /Tm(3+) /Ho(3+) were prepared successfully via a simple and reproducible hydrothermal route using EDTA as the chelating agent. Their phase structure and surface morphology were studied using powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD patterns revealed that all the samples were pure hexagonal phase NaYF4. SEM images showed that Yb(3+)/Tm(3+)/Ho(3+) tri-doped NaYF4 were hexagonal micro-prisms. Upconversion photoluminescence spectra of Yb(3+)/Tm(3+)/Ho(3+) tri-doped NaYF4 micro-crystals with various dopant concentrations under 980 nm excitation with a 665 mW pump power were studied. Tunable multicolor (purple, purplish blue, yellowish green, green) and white light were achieved by simply adjusting the Ho(3+) concentration in 20%Yb(3+)/1%Tm(3+)/xHo(3+) tri-doped NaYF4 micro-crystals. Furthermore, white-light emissions could be obtained using different pump powers in 20%Yb(3+)/1%Tm(3+)/1%Ho(3+) tri-doped NaYF4 micro-crystals at 980 nm excitation. The pump power-dependent intensity relationship was studied and relevant energy transfer processes were discussed in detail. The results suggest that Yb(3+)/Tm(3+) Ho(3+) tri-doped NaYF4 micro-crystals have potential applications in optoelectronic devices such as photovoltaic, plasma display panel and white-light-emitting diodes.

  7. Efficient first-order resonant near-infrared quantum cutting in {beta}-NaYF{sub 4}:Ho{sup 3+},Yb{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Yu, D.C.; Huang, X.Y.; Ye, S. [State Key Laboratory of Physics and Chemistry of Luminescence, and Institute of Optical Communication Materials, South China University of Technology, Guangzhou 510641 (China); Zhang, Q.Y., E-mail: qyzhang@scut.edu.cn [State Key Laboratory of Physics and Chemistry of Luminescence, and Institute of Optical Communication Materials, South China University of Technology, Guangzhou 510641 (China)

    2011-10-13

    Graphical abstract: Highlights: > Near-infrared quantum cutting has been demonstrated in {beta}-NaYF{sub 4}: Ho{sup 3+}, Yb{sup 3+}. > Underlying mechanism for the two-photon quantum cutting is analyzed. > The quantum cutting can occur through a cooperative and a first-order resonant energy transfer processes. - Abstract: We demonstrated an efficient two-photon near-infrared (NIR) quantum cutting (QC) in Ho{sup 3+}-Yb{sup 3+} co-doped hexagonal {beta}-NaYF{sub 4}, which could efficiently convert an incident high-energy photon in the wavelength region of 300-550 nm into two NIR photons. Underlying mechanism for the two-photon NIR-QC process is analyzed in terms of static and dynamic photoemission and monitored excitation spectra. It is found that NIR-QC can occur through two possible energy transfer (ET) approaches: (i) the excited Ho{sup 3+}:{sup 5}F{sub 3} state may simultaneously excite two Yb{sup 3+} neighbors via a cooperative ET process, and (ii) the NIR-QC can be feasibly induced by a first Ho{sup 3+}({sup 5}S{sub 2},{sup 5}F{sub 4}) + Yb{sup 3+}({sup 2}F{sub 7/2}) {yields} Ho{sup 3+}({sup 5}I{sub 6}) + Yb{sup 3+}({sup 2}F{sub 5/2}) resonant ET process and a sequential {sup 5}I{sub 6} {yields} {sup 5}I{sub 8} transition of Ho{sup 3+}. This novel NaYF{sub 4}:Ho{sup 3+},Yb{sup 3+} NIR-QC phosphor, may explore a new approach to maximize the performance of solar cells.

  8. Effect of Tb and Al substitution within the rare earth and cobalt sublattices on magnetothermal properties of Dy0.5Ho0.5Co2

    Science.gov (United States)

    Chzhan, V. B.; Tereshina, E. A.; Mikhailova, A. B.; Politova, G. A.; Tereshina, I. S.; Kozlov, V. I.; Ćwik, J.; Nenkov, K.; Alekseeva, O. A.; Filimonov, A. V.

    2017-06-01

    The effect of Tb and Al substitution within the rare earth and cobalt sublattices on structural and magnetothermal properties of Dy0.5Ho0.5Co2 has been studied. Multicomponent Laves phase alloys Tbx(Dy0.5Ho0.5)1-xCo2-yAly (x = 0, 0.3, 0.4, 0.5; y = 0, 0.25) synthesized using high-purity metals have been studied using X-ray diffraction analysis, heat capacity and magnetocaloric measurements. Dy0.5Ho0.5Co2 has a first order phase transition at the Curie temperature TC ≈ 110 K. Both Tb and Al substitution leads to increase of the TC. The increasing Tb content leads to the decreases slightly the MCE and all the transitions near the Curie temperature are of the first order. As for the Al-containing compounds, MCE measurements show that the phase transition type changes from the first to the second-order. The advantage of Tbx(Dy0.5Ho0.5)1-xCo1.75Al0.25 as compared with Al-free alloys is 'table-like' behavior of MCE.

  9. Thermoelastic properties of ScB2, TiB2, YB4 and HoB4: Experimental and theoretical studies

    DEFF Research Database (Denmark)

    Waśkowska, A.; Gerward, Leif; Staun Olsen, J.

    2011-01-01

    High-pressure X-ray diffraction in ScB2, TiB2, YB4 and HoB4 powders and single crystals has been studied using synchrotron radiation as well as conventional X-rays. The experimental results are supported by calculations using density functional theory. ScB2, YB4 and HoB4 are hard materials (bulk...... modulus 180–200 GPa), while TiB2 may be classified as superhard (bulk modulus about 260 GPa). We report here first experimental and theoretical determinations of the bulk modulus for HoB4 (195(5) and 198.2 GPa, respectively), and first experimental values of the bulk modulus for ScB2 (196(2) GPa) and YB4...

  10. Measurement of formation cross sections of short-lived nuclei by 14 MeV neutron. Nd, Sm, Dy, Er, Yb

    Energy Technology Data Exchange (ETDEWEB)

    Sakane, H.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan). School of Engineering; Iida, T.; Takahashi, A.

    1997-03-01

    Eight neutron activation cross sections producing the nuclei with half-lives between 3 min and 24 min were obtained at the energy range between 13.4 and 14.9 MeV by activation method. The cross sections were {sup 146}Nd(n,p){sup 146}Pr, {sup 154}Sm(n,{alpha}){sup 151}Nd, {sup 162}Dy(n,p){sup 162}Tb, {sup 163}Dy(n,np){sup 162}Tb, {sup 163}Dy(n,p){sup 163}Tb, {sup 164}Dy(n,p){sup 164}Tb, {sup 170}Er(n,{alpha}){sup 167}Dy, {sup 174}Yb(n,p){sup 170}Tm. {sup 163}Dy(n,np){sup 162}Tb (T{sub 1/2}=7.7 min) was obtained for the first time. Present results are compared with previous results and the evaluated data of JENDL-3 and ENDF/B-VI. There are some discrepancies between present results and the JENDL-3 and ENDF/B-VI. (author)

  11. Role of Yb3+ ions on enhanced ~2.9 μm emission from Ho3+ ions in low phonon oxide glass system

    Science.gov (United States)

    Balaji, Sathravada; Gupta, Gaurav; Biswas, Kaushik; Ghosh, Debarati; Annapurna, Kalyandurg

    2016-07-01

    The foremost limitation of an oxide based crystal or glass host to demonstrate mid- infrared emissions is its high phonon energy. It is very difficult to obtain radiative mid-infrared emissions from these hosts which normally relax non-radiatively between closely spaced energy levels of dopant rare earth ions. In this study, an intense mid-infrared emission around 2.9 μm has been perceived from Ho3+ ions in Yb3+/Ho3+ co-doped oxide based tellurite glass system. This emission intensity has increased many folds upon Yb3+: 985 nm excitation compared to direct Ho3+ excitations due to efficient excited state resonant energy transfer through Yb3+: 2F5/2 → Ho3+: 5I5 levels. The effective bandwidth (FWHM) and cross-section (σem) of measured emission at 2.9 μm are assessed to be 180 nm and 9.1 × 10-21 cm2 respectively which are comparable to other crystal/glass hosts and even better than ZBLAN fluoride glass host. Hence, this Ho3+/Yb3+ co-doped oxide glass system has immense potential for the development of solid state mid-infrared laser sources operating at 2.9 μm region.

  12. Role of Yb(3+) ions on enhanced ~2.9 μm emission from Ho(3+) ions in low phonon oxide glass system.

    Science.gov (United States)

    Balaji, Sathravada; Gupta, Gaurav; Biswas, Kaushik; Ghosh, Debarati; Annapurna, Kalyandurg

    2016-07-04

    The foremost limitation of an oxide based crystal or glass host to demonstrate mid- infrared emissions is its high phonon energy. It is very difficult to obtain radiative mid-infrared emissions from these hosts which normally relax non-radiatively between closely spaced energy levels of dopant rare earth ions. In this study, an intense mid-infrared emission around 2.9 μm has been perceived from Ho(3+) ions in Yb(3+)/Ho(3+) co-doped oxide based tellurite glass system. This emission intensity has increased many folds upon Yb(3+): 985 nm excitation compared to direct Ho(3+) excitations due to efficient excited state resonant energy transfer through Yb(3+): (2)F5/2 → Ho(3+): (5)I5 levels. The effective bandwidth (FWHM) and cross-section (σem) of measured emission at 2.9 μm are assessed to be 180 nm and 9.1 × 10(-21) cm(2) respectively which are comparable to other crystal/glass hosts and even better than ZBLAN fluoride glass host. Hence, this Ho(3+)/Yb(3+) co-doped oxide glass system has immense potential for the development of solid state mid-infrared laser sources operating at 2.9 μm region.

  13. Study of optical absorption, visible emission and NIR–vis luminescence spectra of Tm{sup 3+}/Yb{sup 3+}, Ho{sup 3+}/Yb{sup 3+} and Tm{sup 3+}/Ho{sup 3+}/Yb{sup 3+} doped tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Seshadri, M., E-mail: seshumeruva@gmail.com [Institute of Physics, University of Campinas, UNICAMP, P.O. Box 6165, Campinas 13083-970 (Brazil); Barbosa, L.C.; Cordeiro, C.M.B.; Radha, M. [Institute of Physics, University of Campinas, UNICAMP, P.O. Box 6165, Campinas 13083-970 (Brazil); Sigoli, F.A. [Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, Campinas 13083-970 (Brazil); Ratnakaram, Y.C. [Department of Physics, Sri Venkateswara University, SVU, Tirupat 517502 (India)

    2015-10-15

    Tm{sup 3+}/Yb{sup 3+}, Ho{sup 3+}/Yb{sup 3+} co-doped and Tm{sup 3+}/Ho{sup 3+}/Yb{sup 3+} triply doped TeO{sub 2}–Bi{sub 2}O{sub 3}–ZnO–Li{sub 2}O–Nb{sub 2}O{sub 5} (TBZLN) tellurite glasses were prepared by melt quenching method. Judd–Ofelt intensity parameters (Ω{sub λ}, λ=2, 4 and 6), radiative transition probabilities, branching ratios and radiative lifetimes of Tm{sup 3+}, Ho{sup 3+} ions in co-doped TBZLN glasses were calculated from the optical absorption spectra. Excitation, visible luminescence and decay lifetimes in visible region were also investigated. The stimulated emission and gain cross-sections for the Tm{sup 3+}:{sup 3}F{sub 4}→{sup 3}H{sub 6} (1700 nm) and Ho{sup 3+}:{sup 5}I{sub 7}→{sup 5}I{sub 8} (1956 nm) transitions in co-doped TBZLN glasses have been analyzed and compared with those of other reported glasses. Up-conversion luminescence was observed in TBZLN glasses under 980 nm laser excitation and energy transfer mechanisms have been discussed. Finally, CIE color co-ordinates were calculated and it is observed that the color co-ordinates fall in blue and green regions for Tm{sup 3+}/Yb{sup 3+} and Ho{sup 3+}/Yb{sup 3+} co-doped TBZLN glasses, respectively. A subsequent shift in color co-ordinates from green to greenish-yellow region has been observed with an increase in the concentration (0.1, 0.5 and 1.0 mol%) of Tm{sup 3+} ions in Tm{sup 3+}/Ho{sup 3+}/Yb{sup 3+} triply doped TBZLN glasses. - Highlights: • High degree of covalecy of RE–O bond in co-doped TBZLN glasses was observed. • Tm{sup 3+}:{sup 1}D{sub 2}→{sup 3}F{sub 4} and Ho{sup 3+}:{sup 5}F{sub 4}({sup 5}S{sub 2})→{sup 5}I{sub 8} transitions show high emission cross-section. • Visible and strong 793 nm emission was observed when pumped by 980 nm diode laser. • Triply doped glasses exhibits tunable emission intensity by increasing Tm{sup 3+} ions.

  14. Enhancement of 2.0 μm fluorescence emission in new Ho3+/Tm3+/Yb3+ tri-doped tellurite glasses

    Science.gov (United States)

    Cheng, Pan; Yang, Feng-jing; Zhou, Zi-zhong; Huang, Bo; Wu, Li-bo; Zhou, Ya-xun

    2016-09-01

    For enhancing the 2.0 μm band fluorescence of Ho3+, a certain amount of WO3 oxide was introduced into Ho3+/Tm3+/Yb3+ tri-doped tellurite glass prepared using melt-quenching technique. The prepared tri-doped tellurite glass was characterized by the absorption spectra, fluorescence emission and Raman scattering spectra, together with the stimulated absorption, emission cross-sections and gain coefficient. The research results show that the introduction of WO3 oxide can further improve the 2.0 μm band fluorescence emission through the enhanced phonon-assisted energy transfers between Ho3+/Tm3+/Yb3+ ions under the excitation of 980 nm laser diode (LD). Meanwhile, the maximum gain coefficient of Ho3+ at 2.0 μm band reaches about 2.36 cm-1. An intense 2.0 μm fluorescence emission can be realized.

  15. Molten solvent extraction behavior of trivalent La, Sm, Dy, and Yb withtri-n-butyl phosphate into molten paraffin wax at 60 ℃

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The extraction behavior of La3+, Sm3+, Dy3+, and Yb3+ in sodium acetate-acetic acid medium was studied with tri-n-butyl phosphate (TBP) at 60 ℃ using paraffin wax as a diluent. The extraction percentage is greater than 85% in the pH range of 6 to 8. The result of slope analysis method indicates that the compositions of the extracted species are different between the light and heavy rare earths. The formula of the extracted species is found to be La(TBP)(OH)(Ac)2for La3+ and Yb(TBP)(OH)3 for Yb3+. The effects of extracting time, the concentration of TBP in the organic phase and salts on the extraction efficiency were also discussed.

  16. Crystallization and magnetic characterizations of DyIG and HoIG nanopowders fabricated using citrate sol-gel

    Directory of Open Access Journals (Sweden)

    Dao Thi Thuy Nguyet

    2016-06-01

    Full Text Available Dy and Ho iron garnets in form of nanoparticles were synthesized by citrate sol-gel method. Phase formation, lattice constant and average crystallite sizes of the samples were determined via XRD measurements. Morphology and particle size distribution were studied by TEM and chemical composition was checked by EDX. Magnetic measurements in temperature range 5–600 K and in the maximum applied field of 50 kOe were carried out by using SQUID and VSM. Their magnetic parameters, including Curie temperature, magnetization compensation temperature, spontaneous magnetization, high-field susceptibility, magnetic coercivity were discussed in the framework of three interacting magnetic sublattices, magnetocrystalline anisotropy, core-shell model and compared to those of the bulk materials. Based on these analyses further evaluation on the crystallinity and homogeneity of the samples has been made.

  17. Synthesis of Gd2O3:Ho3+/Yb3+ upconversion nanoparticles for latent fingermark detection on difficult surfaces

    Science.gov (United States)

    Kumar, A.; Tiwari, S. P.; Singh, A. K.; Kumar, K.

    2016-07-01

    Infrared to visible upconversion fluorescent nanoparticles of Gd2O3 codoped with Ho3+/Yb3+ ions are synthesized via thermal decomposition process. The X-ray diffraction analysis of as-synthesized nanoparticles and annealed sample at 1000 °C has shown body-centered cubic phase of Gd2O3. The synthesized phosphor has shown intense green emission upon 980-nm excitation. High-contrast latent fingermarks on some difficult semi-porous and non-porous surfaces under 980-nm diode laser excitation were developed through powder dusting and colloidal solution spraying techniques and the results are compared with the commercial green luminescent fingermark powder. The latent fingermarks were developed on transparent (biological glass slides), single-color (aluminum foil) and multicolor (plywood, plastic bottle and book cover page) background surfaces. The present study depicts that the upconversion-based latent fingermarks detection using Gd2O3:Ho3+/Yb3+ phosphor material is suitable over the other conventional powders and has potential for practical applications in forensic science.

  18. Clinical trial of {sup 165}Dy-HMA and {sup 166}Ho-CHICO in the treatment of Rheumatoid knee synovitis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. Y.; Yoo, D. H.; Bae, S. C.; Jun, J. B. [Hanyang University, Seoul (Korea, Republic of); Lim, S. M.; Hong, S. W.; Lee, S. Y.; Cheon, D. G.; Kim, S. J. [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1997-07-01

    The untreated, chronic synovial inflammation leads to pannus formation and eventual destruction of the articular cartilage. In cases where medical therapy was unsuccessful, surgical or radiation synovectomy is necessary especially in the knee joints. The advantages of radiation synovectomy over surgical synovectomy are (1) greater destruction of diseased synovium, (2) reduced potential for blood clots and infection, (3) no requirement for anesthesia, and (4) less costly and less time consuming. Recently KAERI developed Dy-165 HMA, which was characterized by the absence of iron and a higher concentration of dysprosium. And then more recently KAERI also developed {sup 166}Ho-CHICO, which was characterized by relatively longer half-life(26.8 hr), more biological due to organic nature of chitosan, more even spatial distribution due to colloidal solution and more absorbable to synovium than Dy-165 HMA. We studied to evaluate the efficacy and safety of radiation synovectomy with Dy-165 HMA and {sup 166}Ho-CHICO in chronic rheumatoid synovitis with knee. The present study indicates that the Dy-165 HMA and {sup 166}Ho-CHICO are an effective and safe agent for radiation synovectomy. But further large scaled long-term follow up study and controlled study with steroid only are required. 15 refs. (author)

  19. Preparation of {sup 166} Dy/{sup 166} Ho-Macro aggregates as an In vivo generator system for the treatment of arthrophaties; Preparacion de {sup 166} Dy/{sup 166} Ho-Macro agregados como un sistema de generador In vivo para el tratamiento de artropatias

    Energy Technology Data Exchange (ETDEWEB)

    Aldama A, T.K

    2003-07-01

    The present work reports the obtention of macro aggregates of hydroxides of Dysprosium-166/Holmium-166 ({sup 166} Dy/{sup 166} Ho-MH), as a generator system in vivo to be used in the treatment of arthritis rheumatoid. The {sup 166} Dy was obtained by neutron irradiation of {sup 166} DyO{sub 3} (enriched to 98.45%) by 20 h in the TRIGA Mark III Reactor and 50 h of decay, to the oxide of {sup 166} Dy/{sup 166} Ho formed, it was added HCl 0.12 N to obtain a final volume of 3.5 ml of solution of {sup 166} Dy/{sup 166} Ho chloride. The solution of {sup 166D}yCl{sub 3} solution was obtained with an activity of 3.502 mCi (129 MBq), appropriate for the preparation of the radiopharmaceutical {sup 166} Dy/{sup 166} Ho-MH. The separation of the {sup 166} Dy from the {sup 166} Ho, was carried out by chromatography in an cation exchange column, gaining an appropriate separation, obtaining a {sup 166} Dy with a radionuclide purity greater than 90%. The {sup 166} Dy/{sup 166} Ho-MH were prepared by addition to the solution of {sup 166} DyCI{sub 3} NaOH 0.5 N low ultrasonic bath with later centrifugation, decanted and resuspension in saline solution, obtaining a radiopharmaceutical with a generator system {sup 166} Dy/ {sup 166} Ho with particles of size average of 3 {mu}m, in form of {sup 166} Dy / {sup 166} Ho-MH. Under these conditions, it was obtained a radiochemical yield greater than 99%. The microscopic analysis and of filtration showed that the formulation doesn't present particles smaller than to 1 {mu}m, neither greater to 50 {mu}m, which will allow, the quick phagocytosis for the synoviocytes of the synovial membrane, and by consequence, an homogeneous distribution of the radiation dose could exist. The sedimentation velocity for the formulated suspension is of 0.04 cm/min that it will allow the administration of homogeneous activities of the radiopharmaceutical, to the no deposit in the injection devices. The studies of stability in vitro indicate us that inside

  20. Family of defect-dicubane Ni4Ln2 (Ln = Gd, Tb, Dy, Ho) and Ni4Y2 complexes: rare Tb(III) and Ho(III) examples showing SMM behavior.

    Science.gov (United States)

    Zhao, Lang; Wu, Jianfeng; Ke, Hongshan; Tang, Jinkui

    2014-04-07

    Reactions of Ln(III) perchlorate (Ln = Gd, Tb, Dy, and Ho), NiCl2·6H2O, and a polydentate Schiff base resulted in the assembly of novel isostructural hexanuclear Ni4Ln2 complexes [Ln = Gd (1), Tb (2), Dy (3), Ho (4)] with an unprecedented 3d-4f metal topology consisting of two defect-dicubane units. The corresponding Ni4Y2 (5) complex containing diamagnetic Y(III) atoms was also isolated to assist the magnetic studies. Interestingly, complexes 2 and 3 exhibit SMM characteristics and 4 shows slow relaxation of the magnetization. The absence of frequency-dependent in-phase and out-of-phase signals for the Ni-Y species suggests that the Ln ions' contribution to the slow relaxation must be effectual as previously observed in other Ni-Dy samples. However, the observation of χ″ signals with zero dc field for the Ni-Tb and Ni-Ho derivatives is notable. Indeed, this is the first time that such a behavior is observed in the Ni-Tb and Ni-Ho complexes.

  1. Frustrated pyrochlore oxides, Y2Mn2O7, Ho2Mn2O7, and Yb2Mn2O7: Bulk magnetism and magnetic microstructure

    DEFF Research Database (Denmark)

    Greedan, J.E.; Raju, N.P.; Maignan, A.

    1996-01-01

    The bulk magnetic properties, including de and ac susceptibilities and heat capacity, of the pyrochlore oxides Ho2Mn2O7 and Yb2Mn2O7 are reported and compared with those of the previously studied Y2Mn2O7. In the latter case the magnetic Mn4+ ions occupy the 16c sites in Fd3m which define...... a potentially frustrated three-dimensional array of corner sharing tetrahedra. For Ho2Mn2O7 and Yb2Mn2O7 magnetic rare earth ions occupy the 16d sites, as shown by powder neutron diffraction, which are topologically equivalent to the 16c sites but displaced by a vector (1/2 1/2 1/2). Ho2Mn2O7 and Yb2Mn2O7....... Surprisingly, neutron diffraction data for both Ho2Mn2O7 and Yb2Mn2O7 show resolution limited reflections of magnetic origin in contrast to the heat capacity results. The resolution of the neutron diffraction data places a minimum on the correlation length of 100 Angstrom. Small angle neutron scattering data...

  2. Enhanced effect of Er3+ ions on 2.0 and 2.85 μm emission of Ho3+/Yb3+ doped germanate-tellurite glass

    Science.gov (United States)

    Lu, Yu; Cai, Muzhi; Cao, Ruijie; Tian, Ying; Huang, Feifei; Xu, Shiqing; Zhang, Junjie

    2016-10-01

    We report what we believe is the first demonstration of the enhanced Ho3+ 2.0 μm (2.1 times) and 2.85 μm (2.6 times) emission by addition of Er3+ in the Ho3+/Yb3+ co-doped germanate-tellurite (GT) glass with optimized extra-low hydroxyl content ∂OH- (0.118 cm-1). Meanwhile, enhanced 2.0 and 2.85 μm emission cross-sections (5.78 × 10-21 and 17.9 × 10-21 cm2) can be approximately increased 1.5 times higher, respectively. The enhanced 2.0 and 2.85 μm emission upon excitation of a conventional 980 nm laser diode are investigated by the analysis of energy transfer. In addition, the energy transfer mechanism and coefficient (CDA) from Yb3+ to Ho3+ and Er3+ to Ho3+ have been investigated in detail. Our results indicate that Ho3+/Er3+/Yb3+ triply-doped GT glass is a promising material for 2.0 μm and 3 μm fiber laser.

  3. Upconversion Luminescence Properties of Ho3+, Tm3+, Yb3+ Co-Doped Nanocrystal NaYF4 Synthesized by Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Nanocrystal of upconversion (UC) phosphor Ho3+, Tm3+, and Yb3+ co-doped NaYF4 was prepared by the hydrothermal method in the presence of the complexing agent EDTA. Under 980 nm diode laser excitation, the impact of different concentrations of Ho3+ ion on the UC luminescence intensity was discussed. The law of luminescence intensity versus pump power shows that the 474 nm blue emission, 538 nm green emission, and 642 nm red emission are all due to the two-photon process, while the 450 nm blue emission is a three-photon process. The UC mechanism and processes were also analyzed. The sample was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The result shows that Ho3+, Tm3+, and Yb3+ co-doped NaYF4 prepared by the hydrothermal method exhibits a hexagonal nanocrystal.

  4. Ionic Transport Properties in Nanocrystalline Ce0.8A0.2O2-δ (with A = Eu, Gd, Dy, and Ho) Materials.

    Science.gov (United States)

    Baral, Ashok Kumar; Sankaranarayanan, V

    2010-01-30

    The ionic transport properties of nanocrystalline 20 mol% Eu, Gd, Dy, and Ho doped cerias, with average grain size of around 14 nm were studied by correlating electrical, dielectric properties, and various dynamic parameters. Gd-doped nanocrystalline ceria shows higher value of conductivity (i.e., 1.8 × 10-4 S cm-1 at 550°C) and a lower value of association energy of oxygen vacancies with trivalent dopants Gd3+ (i.e., 0.1 eV), compared to others. Mainly the lattice parameters and dielectric constants (ε∞) are found to control the association energy of oxygen vacancies in these nanomaterials, which in turn resulted in the presence of grain and grain boundary conductivity in Gd- and Eu-doped cerias and only significant grain interior conductivity in Dy- and Ho-doped cerias.

  5. Theoretical investigations on magnetic entropy change in amorphous and crystalline systems: Applications to RAg (R=Tb, Dy, Ho) and GdCuAl

    Energy Technology Data Exchange (ETDEWEB)

    Ranke, P.J. von, E-mail: von.ranke@uol.com.br [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Nóbrega, E.P. [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Caldas, A. [Sociedade Unificada de Ensino Superior e Cultura, SUESC, 20211-351 Rio de Janeiro, RJ (Brazil); Alho, B.P. [Instituto de Aplicação Fernando Rodrigues da Silveira, Universidade do Estado do Rio de Janeiro, Rua Santa Alexandrina, 288, 20260-232 RJ (Brazil); Ribeiro, P.O.; Alvarenga, T.S.T.; Lopes, P.H.O.; Sousa, V.S.R. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Carvalho, A. Magnus G. [Laboratório Nacional de Luz Síncrotron, CNPEM, 13083-970 Campinas, SP (Brazil); Oliveira, N.A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil)

    2014-11-15

    We report theoretical investigations on the magnetic entropy changes in amorphous systems through two different assumptions. In the first assumption, the HPZ-anisotropic model is considered to deal with the random direction of magnetic moments, where the amorphous RAg (R=Tb, Dy and Ho) were used as prototypes systems. In the second assumption, the amorphisation is parameterized through the exchange interaction distribution and GdCuAl, in amorphous and crystalline structures, were considered as prototypes systems. Comparisons between the magnetic entropy changes under amorphisation and under the usual magnetic field variation were performed. The model reveals the dependence of refrigerant capacity on the amorphisation parameter, and an optimum amorphisation parameter was calculated. - Highlights: • Theoretical investigation on RAg (R=Tb, Dy and Ho) and GdCuAl amorphous alloys. • Magnetic entropy changes in GdCuAl in both amorphous and crystalline structures. • The refrigerant capacity was compared in both amorphous and crystalline phases.

  6. Synthesis and structural characterization of the stoichiometric elpasolites of Dy{sup 3+} and Ho{sup 3+}; Sintesis y caracterizacion estructural de las elpasolitas estequiometricas de Dy{sup 3+} y Ho{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo, R.; Soto B, A. [Facultad de Ciencias Fisicas y Matematicas, Universidad de Chile, Beauchef 850, Casilla 2777, Santiago (Chile); Navarro, G. [Instituto de Ciencias Basicas, Facultad de Ingenieria, Universidad Diego Portales, Av. Ejercito 441, Casilla 298-V, Santiago (Chile); Martin, V. [Grupo de Materiales Nucleares, Comision Chilena de Energia Nuclear, La Reina, Casilla 188-D, Santiago (Chile)

    2005-07-01

    In this research paper, we report an updated set of experimental data, mainly structural in character, accurately determined for pure elpasolite systems such as Cs{sub 2}NaLnCI{sub 6}; M{sup 3+} = Dy{sup 3+}(f{sup 9}), Ho(f{sup 10}), where the trivalent lanthanide ions occupy sites of octahedral symmetries. There is a vast amount of experimental data from spectroscopic techniques for this type of systems both, pure and doped as well as several attempts leading to the identification and assignment of the various peaks for the associated spectra. The understanding of the experimental data, is central and most relevant, when the many complexities observed in both, the absorption and emission spectra are taken into account showing up the need for carrying out new experiments and developing more general physical models in the spectroscopy of solid state physics. These models should be able to accommodate both the long and short range interactions as well as to include, in an explicit form, the coupling between the internal and the external vibrations for these systems. A further reason to preclude more comprehensive theoretical studies in this area is the well known fact that, for these systems the experimental data available obtained from X-ray and spectroscopic studies is both scarce and incomplete. In the current research paper, we report updated experimental data, essentially structural in character, obtained in our laboratory utilizing X ray diffraction for powders and we also report a neutron diffraction pattern for the Cs{sub 2}NaHoCl{sub 6}. (Author) 37 refs., 4 tabs., 7 figs.

  7. Photoelectron spectra of the late rare-earth misfit layer compounds (LnS)(1+x)TS2 (Ln=Tb, Dy, Ho; T=Nb, Ta)

    NARCIS (Netherlands)

    Fang, CM; Wiegers, GA; Haas, C

    1997-01-01

    Photoemission spectra (XPS and UPS) are presented for the valence band of misfit layer compounds (LnS)(1+x)TS2 with Ln = Dy, Ho or Tb; T = Nb or Ta. The Nb 4d(x)2 (or Ta 5d(x)2) conduction band is almost filled, which indicates a charge transfer of slightly less than one electron per T from the LnS

  8. Full potential calculations and atom in molecule analysis of the bonding properties of perovskites Borides XRh3B (X=Dy, Ho, Er)

    OpenAIRE

    Ouahrani T.; Merad Boudia I.; Lasri B.

    2013-01-01

    ab initio calculations were performed for the cubic perovskites Borides XRh3B, (X=Dy, Ho, Er). In this work, we have used the augmented plane-wave plus local orbital method to compute the equilibrium structural parameters and electronic structure of densities of states, as well as for the first time, prediction of the thermo-elastic properties of these crystals are presented. The chemical bonding of these compounds has been investigated by using of topological analyses grounded in the theory ...

  9. Crystal structure and Mössbauer studies of the isotypic Fe6-cluster compounds RE15[Fe8C25], RE=Dy, Ho

    KAUST Repository

    Davaasuren, Bambar

    2015-05-01

    The carboferrates RE15[Fe8C25] (RE=Dy, Ho) were prepared from mixtures of the elements by arc-melting followed with subsequent annealing at 1373 K. The crystal structures were determined from single crystal X-ray diffraction data and revealed an isotypic relationship to Er15[Fe8C25] (hP48, P321). The main feature of the crystal structure is given by Fe6 cluster units characterized by covalent Fe-Fe bonding interactions. 57Fe Mössbauer spectra of Dy15[Fe8C25] were fitted by three subspectra with relative spectral weights of about 3:3:2 which is in general agreement with the crystal structure. Below 50 K, an onset of magnetic hyperfine fields at the three iron sites is observed which is supposed to be caused by dipolar fields arising from neighboring, slowly relaxing Dy magnetic moments.

  10. Rhombus-shaped tetranuclear [Ln4] complexes [Ln = Dy(III) and Ho(III)]: synthesis, structure, and SMM behavior.

    Science.gov (United States)

    Chandrasekhar, Vadapalli; Hossain, Sakiat; Das, Sourav; Biswas, Sourav; Sutter, Jean-Pascal

    2013-06-03

    The reaction of a new hexadentate Schiff base hydrazide ligand (LH3) with rare earth(III) chloride salts in the presence of triethylamine as the base afforded two planar tetranuclear neutral complexes: [{(LH)2Dy4}(μ2-O)4](H2O)8·2CH3OH·8H2O (1) and [{(LH)2Ho4}(μ2-O)4](H2O)8·6CH3OH·4H2O (2). These neutral complexes possess a structure in which all of the lanthanide ions and the donor atoms of the ligand remain in a perfect plane. Each doubly deprotonated ligand holds two Ln(III) ions in its two distinct chelating coordination pockets to form [LH(Ln)2](4+) units. Two such units are connected by four [μ2-O](2-) ligands to form a planar tetranuclear assembly with an Ln(III)4 core that possesses a rhombus-shaped structure. Detailed static and dynamic magnetic analysis of 1 and 2 revealed single-molecule magnet (SMM) behavior for complex 1. A peculiar feature of the χM" versus temperature curve is that two peaks that are frequency-dependent are revealed, indicating the occurrence of two relaxation processes that lead to two energy barriers (16.8 and 54.2 K) and time constants (τ0 = 1.4 × 10(-6) s, τ0 = 7.2 × 10(-7) s). This was related to the presence of two distinct geometrical sites for Dy(III) in complex 1.

  11. 2-and 1-D coordination polymers of Dy(III) and Ho(III) with near infrared and visible luminescence by efficient charge-transfer antenna ligand

    Science.gov (United States)

    Oylumluoglu, Gorkem; Coban, Mustafa Burak; Kocak, Cagdas; Aygun, Muhittin; Kara, Hulya

    2017-10-01

    Two new lanthanide-based coordination complexes, [Dy(2-stp).2(H2O)]n (1) and {[Ho(2-stp).3(H2O)]·(H2O)}n (2) [2-stp = 2-sulfoterephthalic acid] were synthesized by hydrothermal reaction and characterized by elemental analysis, UV, IR, single crystal X-ray diffraction and solid state photoluminescence. DyIII and HoIII atoms are eight-coordinated and adopt a distorted square-antiprismatic geometry in complexes 1 and 2, respectively. In compound 1, Dy atoms are coordinated by four bridging 2-stp ligands forming two-dimensional (2D) layer, while Ho atoms by three bridging 2-stp ligands creating one dimensional (1D) double chains in 2. In addition, complexes 1 and 2 display in the solid state and at room temperature an intense yellow emission, respectively; this photoluminescence is achieved by an indirect process (antenna effect). The excellent luminescent performances make these complexes very good candidates for potential luminescence materials.

  12. Wettability of silicon carbide ceramic by Al2O3/Dy2O3 and Al2O3/Yb2O3 systems

    Institute of Scientific and Technical Information of China (English)

    J.A.da Silva; B.M.Moreschi; G.C.R.Garcia; S.Ribeiro

    2013-01-01

    Wettability is an important phenomenon in the liquid phase sintering of silicon carbide (SiC) ceramics.This work involved a study of the wetting of SiC ceramics by two oxide systems,Al2O3/Dy2O3 and Al2O3/Yb2O3,which have so far not been studied for application in the sintering of SiC ceramics.Five mixtures of each system were prepared,with different compositions close to their respective eutectic ones.Samples of the mixtures were pressed into cylindrical specimens,which were placed on a SiC plate and subjected to temperatures above their melting points using a graphite resistance furnace.The behavior of the melted mixtures on the SiC plate was observed by means of an imaging system using a CCD camera and the sessile drop method was employed to determine the contact angle,the parameter that measures the degree of wettability.The results of variation in the contact angle as a function of temperature were plotted in graphic form which showed that the curves displayed a fast decline and good spreading.All the samples of the two systems presented final contact angles of 40° to 10° indicating their good wetting on SiC in the argon atmosphere.The melted/solidified area and interface between SiC and melted/solidified phase were evaluated by scanning electron microscopy (SEM) and their crystalline phases were identified by X-ray diffraction (DRX).The DRX analysis showed that Al2O3 and RE2O3 reacted and formed the Dy3Al5O12 (DyAg) and Yb3Al5O12 (YbAg) phases.The results indicated that the two systems had a promising potential as additives for the sintering of SiC ceramics.

  13. Enhancement of red upconversion emission of cubic phase NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+}/Ce{sup 3+} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wei, E-mail: gaowei@xupt.edu.com; Dong, Jun, E-mail: dongjun@xupt.edu.cn; Liu, Jihong; Yan, Xuewen

    2016-08-15

    Highlights: • The upconversion emission of Ho{sup 3+} ions was tuned from green to red. • The upconversion mechanism of Ho{sup 3+} ions was discussed based on emission spectrum. • The conversion efficiency between Ho{sup 3+} and Ce{sup 3+} were studied and calculated. - Abstract: The red upconversion emission of lanthanide-doped fluoride nanocrystals have great potential applications in color display and anticounterfeiting applications, especially for biological imaging and biomedical. In this work, a significant enhancement of red upconversion emission of Ho{sup 3+} ions was successfully obtained in the cubic phase NaLuF{sub 4} nanocrystals through codoping Ce{sup 3+} ions under NIR 980 nm excitation. The ratio of red-to-green emission of Ho{sup 3+} ions was enhanced about 10-fold, which is due to two efficient cross relaxation processes derived from Ho{sup 3+} and Ce{sup 3+} ions promoted the red emission and quenched the green emission. The upconversion emission and luminescent colors of NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+} nanocrystals were carefully investigated by a confocal microscopy setup. The possible upconversion emission mechanism and conversion efficiency of cross relaxation between Ho{sup 3+} and Ce{sup 3+} ions were discussed in detail. The current study suggests that strong red emission of NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+}/Ce{sup 3+} nanomaterials can be used for color display and anticounterfeiting techniques.

  14. Pencil Beam Spectral Measurements of Ce, Ho, Yb, and Ba Powders for Potential Use in Medical Applications

    Directory of Open Access Journals (Sweden)

    N. Martini

    2015-01-01

    Full Text Available The aim of the present study was to obtain modified X-ray spectra, by using appropriate filter materials for use in applications such as dual energy X-ray imaging. K-edge filtering technique was implemented in order to obtain narrow energy bands for both dual- and single-kVp techniques. Three lanthanide filters (cerium, holmium, and ytterbium and a filter outside lanthanides (barium, with low K-edge, were used to modify the X-ray spectra. The X-ray energies that were used in this work ranged from 60 to 100 kVp. Relative root mean square error (RMSE and the coefficient of variation were used for filter selection. The increasing filter thicknesses led to narrower energy bands. For the dual-kVp technique, 0.7916 g/cm2 Ho, 0.9422 g/cm2 Yb, and 1.0095 g/cm2 Yb were selected for 70, 80, and 90 kVp, respectively. For the single-kVp technique 0.5991 g/cm2 Ce, 0.8750 g/cm2 Ba, and 0.8654 g/cm2 Ce were selected for 80, 90, and 100 kVp, respectively. The filtered X-ray spectra of this work, after appropriate modification, could be used in various X-ray applications, such as dual-energy mammography, bone absorptiometry, and digital tomosynthesis.

  15. Analysis of excitation mechanisms of Ho3+ upconversion luminescence in Ho3+:LiYbF4 (0.2 at %) crystal via photographs of its longitudinal cross sections and via spectral and kinetic characteristics

    Science.gov (United States)

    Kazakov, B. N.; Mikheev, A. V.; Goriev, O. G.; Korableva, S. L.; Semashko, V. V.

    2016-10-01

    The results of a complex analysis of the excitation mechanisms of the up conversion luminescence of Ho3+:LiYbF4 (0.2 at %) crystal are presented. The spatial distribution of the upconversion luminescence intensity is studied by the photographs of longitudinal cross sections at different positions of the laser beam waist with respect to the sample. The surface power density of the pump laser diode radiation (0.755 W, λ = 933 nm) was changed by focusing the beam (similar to Z-scanning). The dependences of the longitudinal luminescence cross sections, as well as of the spectral and kinetic characteristics of Ho3+ and Yb3+ luminescence, on the position of the laser beam waist are determined. It is found that there exist two different mechanisms of the population of the energy levels of Ho3+ ions from which green and red luminescence occur, namely, cooperative sensitization of luminescence and absorption of induced photon groups (JETP Letters, 102 (5), 279 (2015)). It is shown that the contributions of these mechanisms vary both in time and over the crystal volume. All the observed spatial, spectral, and temporal specific features of the upconversion luminescence of Ho3+:LiYbF4 (0.2 at %) crystal are qualitatively explained.

  16. Pressure-induced enhancement of ferroelectricity in multiferroic RMn2O5 (R=Tb,Dy,Ho)

    Science.gov (United States)

    Dela Cruz, C. R.; Lorenz, B.; Sun, Y. Y.; Wang, Y.; Park, S.; Cheong, S.-W.; Gospodinov, M. M.; Chu, C. W.

    2007-11-01

    Measurements of ferroelectric polarization and dielectric constant were done on RMn2O5 (R=Tb,Dy,Ho) with applied hydrostatic pressures of up to 18kbar . At ambient pressure, distinctive anomalies were observed in the temperature profile of both physical properties at critical temperatures marking the onset of long range antiferromegnetic order (TN1) and ferroelectricity (TC1) , as well as at temperatures when anomalous changes in the polarization, dielectric constant, and spin wave commensurability have been previously reported. In particular, the step in the dielectric constant at low temperatures (TC2) , associated with both a drop in the ferroelectric polarization and an incommensurate magnetic structure, was shown to be suddenly quenched upon passing an R -dependent critical pressure. This was shown to correlate with the stabilization of the high ferroelectric polarization state, which is coincident with the commensurate magnetic structure. The observation is suggested to be due to a pressure-induced phase transition into a commensurate magnetic structure, as exemplified by the pressure-temperature (p-T) phase diagrams constructed in this work. The p-T phase diagrams are determined for all three compounds.

  17. Intermediate magnetization state and competing orders in Dy2Ti2O7 and Ho2Ti2O7

    Science.gov (United States)

    Borzi, R. A.; Gómez Albarracín, F. A.; Rosales, H. D.; Rossini, G. L.; Steppke, A.; Prabhakaran, D.; MacKenzie, A. P.; Cabra, D. C.; Grigera, S. A.

    2016-08-01

    Among the frustrated magnetic materials, spin-ice stands out as a particularly interesting system. Residual entropy, freezing and glassiness, Kasteleyn transitions and fractionalization of excitations in three dimensions all stem from a simple classical Hamiltonian. But is the usual spin-ice Hamiltonian a correct description of the experimental systems? Here we address this issue by measuring magnetic susceptibility in the two most studied spin-ice compounds, Dy2Ti2O7 and Ho2Ti2O7, using a vector magnet. Using these results, and guided by a theoretical analysis of possible distortions to the pyrochlore lattice, we construct an effective Hamiltonian and explore it using Monte Carlo simulations. We show how this Hamiltonian reproduces the experimental results, including the formation of a phase of intermediate polarization, and gives important information about the possible ground state of real spin-ice systems. Our work suggests an unusual situation in which distortions might contribute to the preservation rather than relief of the effects of frustration.

  18. Strong paramagnetic crystalline LnVO{sub 4} (Ln: Gd, Tb, Dy, Ho, Er) nanoparticles synthesized by a fabricating method

    Energy Technology Data Exchange (ETDEWEB)

    Bulbul, Berna; Beyaz, Seda, E-mail: sedacan@balikesir.edu.tr

    2016-04-15

    Strong paramagnetic lanthanide orthovanadate (LnVO{sub 4}, Ln: Gd, Tb, Dy, Ho, Er) nanoparticles were synthesized under ambient conditions by a novel precipitation method that is economical and fabricating. To the X-ray diffraction patterns, all samples are well-crystallized zircon type orthovanadate and have pure tetragonal phase. Their crystal sizes increased from 12.58 to 15.12 nm with increasing the ionic radii of lanthanide. As confirmed with the surface observation by a transmission electron microscope, it was identified that their two-dimensional projection is an ellipse with the two major axes. It was seen that the sizes of nanoparticles (14.40nm-70.69 nm) were bigger than the crystal sizes because of their polycrystalline structures. Besides, the particle sizes increased with reduction of ionic radii of lanthanide. The magnetic properties obtained from a vibrating sample magnetometer revealed that all nanoparticles are strong paramagnetic at room temperature showing an increase in molar susceptibility up to 4.79 × 10{sup −1} cm{sup 3} mol{sup −1}. Such highly crystalline, small and paramagnetic nanoparticles could be thought to be convenient for biomedical applications. - Highlights: • A general fabricating method for lanthanide orthovanadate nanoparticles is proposed. • The method generates highly small and crystalline nanoparticles. • The reduction in ionic radius of lanthanide (Ln{sup 3+}) causes to increase particle size.

  19. Comparative analysis of luminescent properties of germanate glass and double-clad optical fibers co-doped with Yb3+/Ho3+ ions

    Science.gov (United States)

    Pietrzycki, Marcin; Kochanowicz, Marcin; Romańczuk, Patryk; Żmojda, Jacek; Miluski, Piotr; Ragiń, Tomasz; Jeleń, Piotr; Sitarz, Maciej; Dorosz, Dominik

    2016-09-01

    The 2 μm and visible emission of low phonon (805 cm-1) germanate glasses and double - clad optical fiber co-doped with 0.7Yb2O3/(0.07-0.7)Ho2O3 ions have been investigated. Luminescence at 2 μm corresponding to Ho3+: 5I7 → 5I8 as well as upconversion luminescence in the visible spectral range corresponding to the Ho3+: 5S2(5F4)→5I8 (545 nm), and Ho3+: 5F5→5I8 (655 nm) transition, respectively were obtained. The optimization of the acceptor content and donor-acceptor ratio were conducted with the purpose of maximizing the luminescence intensity. The highest luminescence intensity in both spectral range was obtained in glass co-doped with 0.7Yb2O3/0.15 Ho2O3. Despite relatively small effective absorption coefficient of the optical fiber comparative analysis of luminescent properties of fabricated glasses (further core) and double - clad optical fiber showed significant contribution of reabsorption process of emitted ASE signal.

  20. Triple-layered perovskite niobates CaRNb3O10 (R = La, Sm, Eu, Gd, Dy, Er, Yb, or Y): new self-activated oxides.

    Science.gov (United States)

    Qin, Lin; Wei, Donglei; Huang, Yanlin; Kim, Sun Il; Yu, Young Moon; Seo, Hyo Jin

    2013-09-16

    Niobates CaRNb3O10 (R = La, Sm, Eu, Gd, Dy, Er, Yb, or Y) were prepared by conventional high-temperature solid-state reaction. The formation of a single-phase compound with triple-layered perovskite-type structure was verified through X-ray diffraction (XRD) studies. The luminescence characteristics such as photoluminescence excitation and emission spectra, X-ray-excited luminescence (XEL), Stokes shift, decay curves, and color coordinates were investigated. The niobates can be efficiently excited by UV light and present luminescence behaviors with rich luminescence colors. Under excitation by ultraviolet radiation, CaRNb3O10 (R = La, Gd, Yb, or Y) exhibits strong blue luminescence due to the self-activation center of the octahedral NbO6 groups, even at room temperature. For the materials of composition CaRNb3O10 (R = Sm, Eu, Dy, or Er), the excitation at the host band produces a characteristic luminescence of rare earth ions, indicating a host-guest energy transfer process. CaRNb3O10 (R = Eu) has the strongest luminescence intensity, which can be efficiently excitated by near UV wavelength. It could be suggested to be a potential candidate for the application on near-UV excited white LEDs.

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

    Science.gov (United States)

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

    2013-01-01

    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.

  2. Ho3+-Yb3+ codoped tellurite based glasses in visible lasers and optical devices: Judd-Ofelt analysis and frequency upconversion

    Science.gov (United States)

    Azam, Mohd; Rai, Vineet Kumar

    2017-04-01

    The optical absorption and frequency upconversion emission in the Ho3+/Yb3+ codoped TeO2-ZnO (TZ), TeO2-ZnO-WO3 (TZW) and TeO2-ZnO-WO3-TiO2 (TZWTi) glasses prepared by melting and quenching method has been studied. Judd-Ofelt theory has been used to calculate the Judd-Ofelt intensity parameters (Ω2, Ω4 and Ω6), transition probabilities, radiative lifetimes, absorption cross sections and the branching ratios. Upconversion (UC) emission bands centered at ∼ 549 nm, ∼658 nm and ∼754 nm are observed upon 980 nm excitation. On codoping with the Yb3+ ions at 3.0 mol% the upconversion emission intensity enhancement of about ∼57 times, ∼342 times and ∼480 times for the green band whereas for the red band arising from the Ho3+ ions it is about ∼71 times, ∼438 times and ∼707 times respectively have been observed. The enhancement observed in the UC emission intensity is explained on the basis of efficient energy transfer from Yb3+ to Ho3+, larger absorption cross section, larger oscillator strengths and increase in the local field corrections factor. The spectroscopic quality factor Ω4/Ω6 has been calculated to get the information about the developed materials for laser applications. The upconversion emission cross section determined on the basis of Judd-Ofelt analysis is found to be maximum for Ho-Yb-TZWTi glass. The nephelauxetic ratio, bonding and covalency parameters have been calculated to know the nature of bonding between the rare earth ions and neighbouring oxygen atoms. The high color purity 83.8% has been reported in the codoped glasses at ∼81.2 W/cm2 pump power density.

  3. Enhanced photovoltaic performance of dye-sensitized solar cells using a new photoelectrode material: upconversion YbF3-Ho/TiO2 nanoheterostructures.

    Science.gov (United States)

    Yu, Jia; Yang, Yulin; Fan, Ruiqing; Wang, Ping; Dong, Yuwei

    2016-02-21

    New up-conversion YbF3-Ho/TiO2 (UC/TiO2) nanoheterostructures are designed and explored as an efficient photoelectrode material to yield dye-sensitized solar cells (DSSCs) with enhanced performance. In this study, we analyze the photogenerated charge transfer properties of the UC/TiO2 nanoheterostructures via surface photovoltage (SPV) and transient photovoltage (TPV) techniques, and the interfacial dynamics of charge transfer and recombination processes in DSSCs using electrochemical impedance spectroscopy (EIS) and open circuit photovoltage decay (OCVD) techniques. It is found that these UC/TiO2 nanoheterostructures combine the upconversion function of YbF3-Ho and the semiconductive merits from TiO2. More importantly, the hetero-junction interface in the UC/TiO2 nanoheterostructures not only induces direct electron-injection from YbF3-Ho to TiO2 by utilizing near-infrared light, but also further improves the existing merits of TiO2 through facilitating the interfacial photoinduced charge separation, suppressing the photoinduced charge recombination and prolonging the lifetimes of excited electrons, which can give further improvement of the photovoltaic performances. When integrating the UC/TiO2 nanoheterostructures into DSSCs, an overall energy conversion efficiency of 8.0% is achieved. There is a 23% enhancement in the overall conversion efficiency and a 19% improvement in the photocurrent, compared to the pristine devices.

  4. The interplay between magnetism and superconductivity in RNi 2B 2C (R dbnd Lu, Tm, Er, Ho, Dy, Tb, Gd)

    Science.gov (United States)

    El Massalami, M.; Bud'ko, S. L.; Giordanengo, B.; Baggio-Saitovitch, E. M.

    1995-02-01

    The superconducting and magnetic phase diagram (characteristic temperatures versus effective ionic radii) of the RNi 2B 2C (R dbnd Lu, Tm, Er, Ho, Dy, Tb, Gd) compounds are considered. Although the gradual degradation of superconductivity can be scaled to the de Gennes factor, ( g-1) 2J( J + 1), the unique reentrant behavior of the HoNi 2B 2C compound and the abrupt quenching of superconductivity for R lighter than Ho are most probably unaccountable within this scheme. Rather, it is argued that their low- T magnetic and transport properties as well as the main features of the interplay between magnetism and superconductivity can be accounted for if the low- T magnetism of HoNi 2B 2C, as reported by Grigereit et al., is generalized to the other isomorphous R members. Thus the onset of the 4f moments antiferromagnetic state at T1 is accompanied by an oscillatory component, which transforms to a commensurate antiferromagnetic state at T2. For HoNi 2B 2C, the pressure and magnetic-field influence on Tc, T1 and T2 will be discussed.

  5. Raman spectra and structural properties of hexagonal Yb{sub 1-x}Dy{sub x}MnO{sub 3} (x = 0, 0.05 and 0.1)

    Energy Technology Data Exchange (ETDEWEB)

    Sattibabu, Bhumireddi; Das, D. [School of engineering Sciences and Technology, University of Hyderabad, Hyderabad-500 046 (India); Bhatnagar, Anil K., E-mail: anilb42@gmail.com [School of engineering Sciences and Technology, University of Hyderabad, Hyderabad-500 046 (India); School of Physics, University of Hyderabad, Hyderabd-500 046 (India)

    2016-05-23

    Single phase Yb{sub 1-x}Dy{sub x}MnO{sub 3} (x= 0, 0.05 and 0.1) samples are prepared by a solid state reaction method. X-ray powder diffraction shows that all samples crystallize in the hexagonal phase with P6{sub 3}cm space group. The structural analysis shows there is increase in lattice parameter c and cell volume of the hexagonal unit cell with Dy substitution and the average bond length between Mn-O increases. Raman spectra show that the phonon peaks of Yb{sub 1-x}Dy{sub x}MnO{sub 3} slightly shift to lower frequencies with doping.

  6. Atomic distribution, local structure and cation size effect in o-R1-xCaxMnO3 (R = Dy, Y, and Ho).

    Science.gov (United States)

    Jiang, Ning; Zhang, X; Yu, Yi

    2013-11-27

    We propose new interatomic potentials for the small rare-earth-based orthorhombic RMnO3 (R = Dy, Y, Ho), which accurately model the structural properties of these extreme cases of lanthanide manganate series. They are further employed to investigate the intrinsic defects in o-RMnO3 and the cation distribution and local structure in o-R1-xCaxMnO3 (R = Dy, Y, Ho). Schottky disorders are found to be the dominant structural defects, and the possibility of a small degree of anti-site disorder of R and Mn ions over A and B sites is found. The introduced Ca dopants tend to form chemically and structurally like CaMnO3 clusters in the lightly doped system, which can be regarded as representations of microscopic phase separation. The local structural disorder is reduced with increasing doping density. For o-R0.5Ca0.5MnO3 (R = Dy, Y, Ho), the charge ordering state is intrinsically favored, and the layer stripe model is shown to be energetically more favorable and structurally more reasonable. Moreover, the tendency to form charge ordered stripes increases with the decrease of R size. The local structure in the layer stripe pattern deviates largely from the average structure: RMnO3-like and CaMnO3-like layers are formed. The size of R ion has a significant influence on the doping effect on Jahn-Teller (JT) distortion and a manganate with a larger R will experience a larger reduction on the anisotropy of Mn-O bonds in Mn(3+)O6 octahedra. However, the change of octahedral tilting upon doping does not vary much with R radii.

  7. Crystal growth, transport, and the structural and magnetic properties of Ln(4)FeGa(12) with Ln = Y, Tb, Dy, Ho, and Er.

    Science.gov (United States)

    Drake, Brenton L; Grandjean, Fernande; Kangas, Michael J; Okudzeto, Edem K; Karki, Amar B; Sougrati, Moulay T; Young, David P; Long, Gary J; Chan, Julia Y

    2010-01-18

    Ln(4)FeGa(12), where Ln is Y, Tb, Dy, Ho, and Er, prepared by flux growth, crystallize with the cubic Y(4)PdGa(12) structure with the Im3m space group and with a = 8.5650(4), 8.5610(4), 8.5350(3), 8.5080(3), and 8.4760(3) A, respectively. The crystal structure consists of an iron-gallium octahedra and face-sharing rare-earth cuboctahedra of the Au(3)Cu type. Er(4)Fe(0.67)Ga(12) is iron-deficient, leading to a distortion of the octahedral and cuboctahedral environments due to the splitting of the Ga2 site into Ga2 and Ga3 sites. Further, interstitial octahedral sites that are unoccupied in Ln(4)FeGa(12) (Ln = Y, Tb, Dy, and Ho) are partially occupied by Fe2. Y(4)FeGa(12) exhibits weak itinerant ferromagnetism below 36 K. In contrast, Tb(4)FeGa(12), Dy(4)FeGa(12), Ho(4)FeGa(12), and Er(4)Fe(0.67)Ga(12) order antiferromagnetically with maxima in the molar magnetic susceptibilities at 26, 18.5, 9, and 6 K. All of the compounds exhibit metallic electric resistivity, and their iron-57 Mossbauer spectra, obtained between 4.2 and 295 K, exhibit a single-line absorption with a 4.2 K isomer shift of ca. 0.50 mm/s, a shift that is characteristic of iron in an iron-gallium intermetallic compound. A small but significant broadening in the spectral absorption line width is observed for Y(4)FeGa(12) below 40 K and results from the small hyperfine field arising from its spin-polarized itinerant electrons.

  8. Electron-magnon interaction in RNiBC (R=Er, Ho, Dy, Tb, and Gd) series of compounds based on magnetoresistance measurements

    Science.gov (United States)

    Fontes, M. B.; Trochez, J. C.; Giordanengo, B.; Bud'ko, S. L.; Sanchez, D. R.; Baggio-Saitovitch, E. M.; Continentino, M. A.

    1999-09-01

    We present a study of the transport and magnetic properties of a series of RNiBC compounds (R=Er, Ho, Dy, Tb, and Gd). All the materials investigated have long range magnetic order at sufficiently low temperatures. Magnetoresistance measurements are presented for a large range of temperatures (T) and magnetic fields (H). We show that below the critical temperature, the temperature dependence of the resistivity is determined by electron scattering due to the elementary excitations (spin waves) of the ordered magnetic phase and the values of the gap in the magnon spectra were derived. Finally we discuss the H×T phase diagram of these materials.

  9. The upconversion luminescence and magnetism in Yb3+/Ho3+ co-doped LaF3 nanocrystals for potential bimodal imaging

    Science.gov (United States)

    Syamchand, Sasidharanpillai S.; George, Sony

    2016-12-01

    Biocompatible upconversion nanoparticles with multifunctional properties can serve as potential nanoprobes for multimodal imaging. Herein, we report an upconversion nanocrystal based on lanthanum fluoride which is developed to address the imaging modalities, upconversion luminescence imaging and magnetic resonance imaging (MRI). Lanthanide ions (Yb3+ and Ho3+) doped LaF3 nanocrystals (LaF3 Yb3+/Ho3+) are fabricated through a rapid microwave-assisted synthesis. The hexagonal phase LaF3 nanocrystals exhibit nearly spherical morphology with average diameter of 9.8 nm. The inductively coupled plasma mass spectrometry (ICP-MS) analysis estimated the doping concentration of Yb3+ and Ho3+ as 3.99 and 0.41%, respectively. The nanocrystals show upconversion luminescence when irradiated with near-infrared (NIR) photons of wavelength 980 nm. The emission spectrum consists of bands centred at 542, 645 and 658 nm. The stronger green emission at 542 nm and the weak red emissions at 645 and 658 nm are assigned to 5S2 → 5I8 and 5F5 → 5I8 transitions of Ho3+, respectively. The pump power dependence of luminescence intensity confirmed the two-photon upconversion process. The nanocrystals exhibit paramagnetism due to the presence of lanthanide ion dopant Ho3+ and the magnetization is 19.81 emu/g at room temperature. The nanocrystals exhibit a longitudinal relaxivity ( r 1) of 0.12 s-1 mM-1 and transverse relaxivity ( r 2) of 28.18 s-1 mM-1, which makes the system suitable for developing T2 MRI contrast agents based on holmium. The LaF3 Yb3+/Ho3+ nanocrystals are surface modified by PEGylation to improve biocompatibility and enhance further functionalisation. The PEGylated nanocrystals are found to be non-toxic up to 50 μg/mL for 48 h of incubation, which is confirmed by the MTT assay as well as morphological studies in HeLa cells. The upconversion luminescence and magnetism together with biocompatibility enables the adaptability of the present system as a nanoprobe for potential

  10. Hexagonal versus perovskite phase of manganite RMnO3 (R=Y,Ho,Er,Tm,Yb,Lu)

    Science.gov (United States)

    Zhou, J.-S.; Goodenough, J. B.; Gallardo-Amores, J. M.; Morán, E.; Alario-Franco, M. A.; Caudillo, R.

    2006-07-01

    The floating-zone method and high-pressure synthesis have been used to obtain the hexagonal and the perovskite RMnO3 (R=Y,Ho,Er,Tm,Yb,Lu) compounds. We have refined the crystal structure and characterized the compounds with measurements of magnetic susceptibility χ(T) and thermal conductivity κ(T) . The systematic change of κ(T) below TN found in all members of the hexagonal RMnO3 family shows that some spin-independent bond-length fluctuation plays an important role in the suppression of κ(T) below TN as well as in the paramagnetic phase. The responsible soft vibrational mode is identified. In contrast, the perovskite RMnO3 shows a phonon-like κ(T) below room temperature, but with an anomalously large critical scattering at TN . A phase diagram of transition temperatures versus the R3+ -ion radius for both hexagonal and perovskite phases is also given.

  11. Direct Measurement of the Mass Difference of Ho163 and Dy163 Solves the Q-Value Puzzle for the Neutrino Mass Determination

    CERN Document Server

    Eliseev, S; Block, M; Chenmarev, S; Dorrer, H; Duellmann, Ch E; Enss, C; Filianin, P E; Gastaldo, L; Goncharov, M; Koester, U; Lautenschlaeger, F; Novikov, Yu N; Rischka, A; Schuessler, R X; Schweikhard, L; Tuerler, A

    2016-01-01

    The atomic mass difference of 163Ho and 163Dy has been directly measured with the Penning trap mass spectrometer SHIPTRAP applying the novel phase imaging ion cyclotron resonance technique. Our measurement has solved the long standing problem of large discrepancies in the Q value of the electron capture in 163Ho determined by different techniques. Our measured mass difference shifts the current Q value of 2555(16) eV evaluated in the Atomic Mass Evaluation 2012 [G. Audi et al., Chin. Phys. C 36, 1157 (2012)] by more than 7 sigma to 2833(30stat)(15sys) eV/c2. With the new mass difference it will be possible, e.g., to reach in the first phase of the ECHo experiment a statistical sensitivity to the neutrino mass below 10 eV, which will reduce its present upper limit by more than an order of magnitude.

  12. Investigation on up-conversion luminescence properties of novel transparent Ho3+-Tm3+-Yb3+ co-doped oxyfluoride glass ceramics

    Science.gov (United States)

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

    2011-06-01

    In the present letter, the transparent oxyfluoride glass ceramics containing Ho3+-Tm3+-Yb3+:NaYF4 were successfully prepared by melt-quenching at 1400°C and subsequent heating at 650-680°C for 1~2 hours . X-ray diffraction (XRD) with Cu Kα radiation (λ=0.154nm) investigation revealed that NaYF4 nano-crystals in the glass ceramics was fabricated. Their sizes were determined by Sherrer's equation. The emission spectra red green and blue up-conversion (UC) under 980nm laser diode (LD) pumping and absorption spectra were measured. Luminescence measurements confirmed the partition of RE ions in nano-crystals NaYF4. The blue red and green UC radiations correspond to the transitions 1G4-3H6, 1G4-3H4 of Tm3+, 5F4, 5S2-5I8, 5F5-5I8, of Ho3+ ions, respectively. This is similar to that in Tm3+-Yb3+ and/or Ho3+-Yb3+ co-doped glass ceramics. To obtain upconversion fluorescence mechanisms, upconversion fluorescence intensity versus LD pump power were analyzed in view of energy levels of rare earth. Up-conversion mechanisms were discussed and the ratio between red, green and blue UC emission bands was found to be varied as a function of temperature of heat treatment and pump power. This result could be mainly attributed to the cross-relaxation between Ho3+ ions. The excellent optical properties and its convenient, low-cost synthesis of the present glass ceramic imply that it is an excellent substitution material for the unobtainable bulk NaYF4 crystal and may have potentially applications in tunable visible laser or many other fields.

  13. Spectrophotometric and pH-Metric Studies of Ce(III, Dy(III, Gd(III,Yb(III and Pr(III Metal Complexes with Rifampicin

    Directory of Open Access Journals (Sweden)

    A. N. Sonar

    2011-01-01

    Full Text Available The metal-ligand and proton-ligand stability constant of Ce(III, Dy(III, Gd(III,Yb(III and Pr(III metals with substituted heterocyclic drug (Rifampicin were determined at various ionic strength by pH metric titration. NaClO4 was used to maintain ionic strength of solution. The results obtained were extrapolated to the zero ionic strength using an equation with one individual parameter. The thermodynamic stability constant of the complexes were also calculated. The formation of complexes has been studied by Job’s method. The results obtained were of stability constants by pH metric method is confirmed by Job’s method.

  14. Synthetic and spectroscopic studies of vanadate glaserites I: Upconversion studies of doubly co-doped (Er, Tm, or Ho):Yb:K{sub 3}Y(VO{sub 4}){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Kimani, Martin M., E-mail: kimani@g.clemson.edu; Chen, Hongyu, E-mail: hongyuc@g.clemson.edu; McMillen, Colin D., E-mail: cmcmill@g.clemson.edu; Anker, Jeffery N., E-mail: janker@clemson.edu; Kolis, Joseph W., E-mail: kjoseph@clemson.edu

    2015-03-15

    The synthesis and upconversion properties of trigonal glaserite-type K{sub 3}Y(VO{sub 4}){sub 2} co-doped with Er{sup 3+}/Yb{sup 3+}, Ho{sup 3+}/Yb{sup 3+}, or Tm{sup 3+}/Yb{sup 3+} were studied. Powder samples were synthesized by solid state reactions at 1000 °C for 48 h, while well-formed hexagonal single crystals of the same were grown hydrothermally using 10 M K{sub 2}CO{sub 3} at 560–650 °C. Infrared-to-visible upconversion by Er{sup 3+}/Yb{sup 3+}, Ho{sup 3+}/Yb{sup 3+}, or Tm{sup 3+}/Yb{sup 3+} codoped-K{sub 3}Y(VO{sub 4}){sub 2} glaserite powder and single crystals was observed, and the upconversion spectral properties were studied as a function of different Er{sup 3+}, Tm{sup 3+}, Ho{sup 3+}, and Yb{sup 3+} ion concentrations. The process is observed under 980 nm laser diode excitation and leads to strong green (552 nm) and red (659 nm) emission for Er{sup 3+}/Yb{sup 3+}, green (549 nm) and red (664 nm) emission for Ho{sup 3+}/Yb{sup 3+}, and blue (475 nm) and red (647 nm) emission for Tm{sup 3+}/Yb{sup 3+}. The main mechanism that allows for up-conversion is attributed the energy transfer among Yb{sup 3+} and the various Er{sup 3+}/Ho{sup 3+}/Tm{sup 3+} ions in excited states. These results illustrate the large potential of co-doped alkali double vanadates for photonic applications involving optoelectronics devices. - Graphical abstract: Synthesis and upconversion in vanadate glaserites. - Highlights: • K{sub 3}Y(VO{sub 4}){sub 2} codoped with Er, Tm, or Ho:Yb were synthesized via solid-state and hydrothermal routes. • Upconversion properties are investigated. • The codoped compounds revealed efficient infrared-to-visible upconversion. • The presented compounds are potential host for solid state lighting.

  15. Spectroscopic properties of KGd(WO{sub 4}){sub 2} single crystals doped with Er{sup 3+}, Ho{sup 3+}, Tm{sup 3+} and Yb{sup 3+} ions: Luminescence and micro-Raman investigations

    Energy Technology Data Exchange (ETDEWEB)

    Kasprowicz, D., E-mail: Dobroslawa.Kasprowicz@put.poznan.pl [Faculty of Technical Physics, Poznan University of Technology, Nieszawska 13 A, 60-965 Poznan (Poland); Brik, M.G. [Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia); Majchrowski, A. [Institute of Applied Physics, Military University of Technology, Kaliskiego 2, 00-908 Warszawa (Poland); Michalski, E. [Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00-908 Warszawa (Poland); Głuchowski, P. [Institute of Low Temperature and Structure Research of Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw (Poland)

    2013-11-15

    Highlights: •Investigations of KGd(WO{sub 4}){sub 2} crystals doped with Ho/Yb/Er and Ho/Tm/Yb/Er ions. •The vibrational properties were studied using micro-Raman spectroscopy. •The multicolor up-converted luminescence was investigated. -- Abstract: KGd(WO{sub 4}){sub 2} single crystals doped with Ho{sup 3+}/Yb{sup 3+}/Er{sup 3+} and Ho{sup 3+}/Tm{sup 3+}/Yb{sup 3+}/Er{sup 3+} ions were grown by means of the Top Seeded Solution Growth (TSSG) method. It was shown that these systems exhibit multicolor up-conversion luminescence in the visible and near-infrared spectral ranges under 980 nm laser excitation. In the investigated crystals the Yb{sup 3+} ions were used as the energy sensitizer ion and the up-converted luminescence originates from transitions between the energy levels of other co-doped rare earth ions such as Er{sup 3+}, Ho{sup 3+} or Tm{sup 3+}, which play the role of the energy activator ions. The vibrational properties of the crystals were investigated using micro-Raman spectroscopy and the role of vibrational energy in the effective energy transfer process between the rare earth ions was discussed. The proposed combinations of activator ions may be suitable for gaining novel materials with effective green, red and near-infrared emission.

  16. A "win-win" nanoplatform: TiO2:Yb,Ho,F for NIR light-induced synergistic therapy and imaging.

    Science.gov (United States)

    Zhou, Jie; Luo, Pei; Sun, Chong; Meng, Lingchang; Ye, Weiran; Chen, Shanshan; Du, Bin

    2017-03-23

    To avoid the defect of low energy transfer efficiency in core-shell UCNP-TiO2 NPs, doping rare earth into TiO2 and improving the photocatalytic activity of TiO2 itself under Vis-NIR light might be a more direct and efficient strategy for high (1)O2 production. Here, we designed a TiO2:Yb,Ho,F-β-CD@DTX/HA nanoplatform using TiO2:Yb,Ho,F as the core, β-CD as the drug carrier, hyaluronic acid (HA) as the capping agent and target, and then applied it for 808 nm induced photodynamic-chemotherapy and 980 nm upconversion fluorescence/MR imaging. The results were as follows: (i) for TiO2 as a photosensitizer, after doping Yb, Ho, F into TiO2, it could directly generate reactive oxygen species under an 808 nm laser; the dopants enhanced the absorption under the UV-Vis-NIR region and increased the electron-hole pair separation. (ii) For TiO2 as the upconversion host, F and Ho also endowed TiO2:Yb,Ho,F with enhanced upconversion fluorescence under a 980 nm laser and T2-MRI contrast performance (r2 = 30.71 mM(-1) s(-1)), respectively, thus, facilitating imaging for deep tissues. (iii) The HA shell outside of β-CD prevented the unexpected leaking of DTX, which improved the target abilities and achieved the enzyme-responsive drug release. The in vitro and in vivo studies also demonstrated the nanosystem could efficiently suppress tumor growth by combination therapy and had excellent imaging (UCL/MR) ability. Particularly, our work was the first example that utilized TiO2 simultaneously as a photosensitizer and upconversion host, which simplified the core-shell UCNP-TiO2 nanocomposites and reached a "win-win" cooperation in NIR-induced photodynamic therapy and UCL imaging.

  17. Near-infrared quantum cutting in Ho{sup 3+}/Yb{sup 3+} co-doped BaZr{sub 0.8}Y{sub 0.2}O{sub 3-δ}

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Tiejin; Yang, Xiaoliang, E-mail: xiaoliangy@xtu.edu.cn; Xia, Wenbin; Gao, Xuejun; Li, Wei; Xiao, Siguo

    2016-09-15

    Highlights: • Ho{sup 3+}/Yb{sup 3+} co-doped BaZr{sub 0.8}Y{sub 0.2}O{sub 3-δ} quantum cutting phosphor is prepared with co-precipitation method. • Ho{sup 3+}/Yb{sup 3+} co-doped BaZr{sub 0.8}Y{sub 0.2}O{sub 3-δ} powder gives strong and pure emission of Ho{sup 3+} in the near infrared region. • Efficient Ho{sup 3+} → Yb{sup 3+}→ Ho{sup 3+} multi-step energy transfer is responsible for the novel quantum cutting properties. • A new method based on luminescence intensity ratio is developed to estimate the quantum cutting efficiency. - Abstract: A novel Ho{sup 3+} → Yb{sup 3+} → Ho{sup 3+} multi-step energy transfer caused quantum cutting under 455 nm excitation is observed in Ho{sup 3+}/Yb{sup 3+} co-doped BaZr{sub 0.8}Y{sub 0.2}O{sub 3-δ} phosphor. During the quantum cutting process, Yb{sup 3+} ions efficiently increase the particle population of {sup 5}I{sub 6} level of H{sub O}{sup 3+}, resulting in 10 and 8 times of enhancement of Ho{sup 3+} emission at 1216 nm ({sup 5}I{sub 6} → {sup 5}I{sub 8}) and 1926 nm ({sup 5}I{sub 7} → {sup 5}I{sub 8}), respectively. It is interesting that the {sup 2}F{sub 5/2} → {sup 2}F{sub 7/2} emission of Yb{sup 3+} ions themselves is very weak although the quantum cutting is performed by the Ho{sup 3+}/Yb{sup 3+} ion-pairs. The result indicates that the Yb{sup 3+} → Ho{sup 3+} back energy transfer in the BaZr{sub 0.8}Y{sub 0.2}O{sub 3-δ} phosphor is quite efficient and helpful for the enhancement of Ho{sup 3+} emission in near infrared region. A new valid method based on luminescence intensity ratio is developed to estimate the quantum cutting efficiency. It is found that the energy transfer form Ho{sup 3+} to Yb{sup 3+} is 52.8% in the phosphor with optimum Ho{sup 3+}/Yb{sup 3+} doping concentration and 90% of near infrared emission of Ho{sup 3+} is performed by the multi-step energy transfer induced quantum cutting.

  18. Magnetic ordering of R{sub 3}Cu{sub 4}Sn{sub 4} (R = Tb, Dy, Ho and Er)

    Energy Technology Data Exchange (ETDEWEB)

    Wawrzynska, E [M Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland); Hernandez-Velasco, J [BENSC, Hahn-Meitner Institut, Glienicker Strasse 100, D-14109 Berlin (Germany); Penc, B [M Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland); Sikora, W [Faculty of Physics and Nuclear Techniques, University of Mining and Metallurgy, Reymonta 19, 30-059 Cracow (Poland); Szytula, A [M Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland); Zygmunt, A [W Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Dorodna 2, 50-950 Wroclaw (Poland)

    2003-08-06

    Neutron diffraction studies of polycrystalline R{sub 3}Cu{sub 4}Sn{sub 4} (R = Tb, Dy, Ho, Er) intermetallic compounds with the orthorhombic Gd{sub 3}Cu{sub 4}Ge{sub 4}-type crystal structure indicate the existence of different magnetic structures. Rare earth atoms occupy two non-equivalent 2d and 4e sublattices. The rare earth magnetic moments order at low temperatures. For R = Tb and Dy the magnetic structures below the Neel temperature are described by the propagation vectors k = (0, 0, 1/2 + {delta}). In these compounds both rare earth sublattices order. For R = Ho the magnetic structure is more complicated. There are two vectors; one of them is k = (0, 1/2, 0) whereas the second one changes with temperature. For the Er compound there is the propagation vector k = (1/2, 1/2, 0) which describes the magnetic ordering in the 2d sublattice and at low temperatures is accompanied by the propagation vector k = (0, 0,{delta}) describing the ordering in the 4e sublattice.

  19. Magnetic structures of R{sub 3}Cu{sub 4}Ge{sub 4} (R=Tb, Dy, Ho, Er)

    Energy Technology Data Exchange (ETDEWEB)

    Wawrzynska, E. E-mail: wawrzyn@castor.if.uj.edu.pl; Hernandez-Velasco, J.; Penc, B.; Szytula, A.; Zygmunt, A

    2003-08-01

    Neutron diffraction studies of polycrystalline R{sub 3}Cu{sub 4}Ge{sub 4} (R=Tb, Dy, Ho, Er) intermetallic compounds with the orthorhombic Gd{sub 3}Cu{sub 4}Ge{sub 4}-type crystal structure indicate complex magnetic structures. In these compounds the rare earth atoms occupy two nonequivalent 2d and 4e sublattices. For R=Tb and Er with decreasing temperature the magnetic moments in the 2d sublattice order first; the 4e sublattice magnetic moments order at lower temperatures. For R=Dy, Ho both sublattices order simultaneously although the magnetic moment values are different for each of them. In the compounds with R=Tb and Er a change of the magnetic structure, connected with the 2d sublattice, is observed near the Neel temperature. This is a transition from the commensurate structure, described by the propagation vector k=(0,((1)/(2)),0) at low temperatures to the incommensurate structure with k=(0,((1)/(2))+{delta},0) at higher temperatures (still below the Neel temperature)

  20. Magnetic structures of R{sub 3}Cu{sub 4}Si{sub 4} (R=Dy, Ho and Er)

    Energy Technology Data Exchange (ETDEWEB)

    Wawrzynska, E. E-mail: e.w.@wp.pl; Hernandez-Velasco, J.; Penc, B.; Szytula, A. E-mail: szytula@if.uj.edu.pl

    2004-09-01

    Polycrystalline samples of R{sub 3}Cu{sub 4}Si{sub 4} (R=Dy, Ho, Er) intermetallics were studied with neutron diffraction methods. All of them crystallize in the orthorhombic structure of Gd{sub 3}Cu{sub 4}Ge{sub 4}-type and order antiferromagnetically at low temperatures. Magnetic moments localized at the rare earth atoms, that occupy two non-equivalent 2d and 4e sublattices, order simultaneously in Dy{sub 3}Cu{sub 4}Si{sub 4}. The order is described by the propagation vector k=(0,((1)/(2)),0) accompanied by k=(0,(1/2)+{delta},(1/2)+{delta}), {delta}=0.025(2). In Ho{sub 3}Cu{sub 4}Si{sub 4} two propagation vectors are needed to model the magnetic order. These are: k=((1/2),0.316(2),(1/2)) for the 4e sublattice, which disorders as the first when the temperature increases, and k=(0,(1/2),0) for the 2d sublattice. A similar situation is observed for Er{sub 3}Cu{sub 4}Si{sub 4} where the propagation vectors are: k=(0,1-{delta},0), {delta}=0.097(2) for the 4e sublattice, which disorders as the first with increasing temperature, and k=(0,(1/2)+{delta},0), {delta}=0.0015(6) for the 2d sublattice.

  1. Magnetocaloric properties of TbN, DyN and HoN nanopowders prepared by the plasma arc discharge method.

    Science.gov (United States)

    Shinde, K P; Jang, S H; Kim, J W; Kim, D S; Ranot, M; Chung, K C

    2015-12-21

    We report for the first time the synthesis of nanopowders of TbN, DyN and HoN crystallized in a cubic structure by the plasma arc discharge (PAD) method and investigate their magnetocaloric properties for magnetic refrigeration applications. The nitridization of terbium, dysprosium and holmium was obtained using a mixture of nitrogen and argon gas inside a discharge chamber with 4 kPa pressure. The structural and microstructural properties of these rare earth nitrides were investigated by using X-ray diffraction and transmission electron microscopy. The studied nitrides undergo a second-order ferromagnetic to paramagnetic phase transition at Curie temperatures of 35.7, 19.9 and 14.2 K for TbN, DyN and HoN, respectively. The magnetocaloric effects were estimated by calculating the magnetic entropy changes from the magnetization data sets measured at the different applied magnetic fields and temperatures. The changes in entropy -ΔSM were found to be 12.0, 13.6 and 24.5 J kg(-1) K(-1) at an applied magnetic field of 5 T.

  2. Enhanced Magnetostriction of a Narrow Hysteresis Tb0.26Dy0.54Ho0.20Fe2 Alloy

    Institute of Scientific and Technical Information of China (English)

    Xingwen PAN; Changsheng ZHANG; Tianyu MA; Mi YAN; Jing LI

    2013-01-01

    In this work,a magnetic annealing method used to enhance the magnetostrictive property of a narrow hysteresis alloy Tb0.26Dy0.54Ho0.20Fe2 is reported.Cylindrical-rod shaped specimen with crystal orientation was fabricated using zone-melting unidirectional solidification technique,followed by annealing in a transverse magnetic field of 366 kA/m.The crystal orientation and bi-phase solidified morphology can be retained after magnetic annealing.A high magnetostriction of 1.508×10-3 was obtained in the magnetically annealed specimen,which is 25.2% larger than the untreated one.Simultaneously,the magnetostriction hysteresis width is slightly enlarged from 4.45 to 6.36 kA/m,which is still much lower than that of the Ho-free Tb0.3Dy0.7Fe2 alloy.The additional anisotropy which is induced by magnetic annealing,as reflected by the magnetic hysteresis loops,is responsible for the enhancement of magnetostrictive performance.

  3. Single-particle and collective mode couplings associated with 1- and 2-directional electronic ordering in metallic RTe3 (R=Ho,Dy,Tb).

    Science.gov (United States)

    Yusupov, R V; Mertelj, T; Chu, J-H; Fisher, I R; Mihailovic, D

    2008-12-12

    The coupling of phonons with collective modes and single-particle gap excitations associated with one- (1d) and two-directional (2d) electronically driven charge-density wave (CDW) ordering in metallic RTe3 is investigated as a function of rare-earth ion chemical pressure (R=Tb,Dy,Ho) using femtosecond pump-probe spectroscopy. From the T dependence of the CDW gap DeltaCDW and the amplitude mode, we find that while the transition to a 1d-CDW ordered state at Tc1 initially proceeds in an exemplary mean-field-like fashion, below Tc1, DeltaCDW is depressed and departs from the mean-field behavior. The effect is apparently triggered by resonant mode mixing of the amplitude mode with a totally symmetric phonon at 1.75 THz. At low temperatures, when the state evolves into a 2d-CDW ordered state at Tc2 in the DyTe3 and HoTe3, additional much weaker mode mixing is evident but no soft mode is observed.

  4. Study on upconversion luminescence and thermal properties of Ho{sup 3+}/Yb{sup 3+} co-doped La{sub 2}O{sub 3}–TiO{sub 2}–ZrO{sub 2} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Minghui; Wen, Haiqin [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Yu, Huimei [Analysis and Testing Center of Inorganic Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Ai, Fei [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Shao, Hui [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003 (China); Pan, Xiuhong; Tang, Meibo; Yu, Jianding; Gai, Lijun [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Liu, Yan, E-mail: liuyan@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China)

    2016-07-05

    Bulk Ho{sup 3+}/Yb{sup 3+} co-doped La{sub 2}O{sub 3}–TiO{sub 2}–ZrO{sub 2} glass spheres were fabricated by aerodynamic levitation method. High concentration of Yb{sup 3+} ions was successfully doped in glasses. The effects of Yb{sup 3+} concentration on mechanical properties, Raman, absorption spectra, thermal stability, and glass forming ability were studied systematically. Green, red, and infrared emissions centered at 550, 662, and 758 nm were obtained at 980 nm excitation. Yellow light from glass spheres can be easily observed by naked eyes. As Yb{sup 3+} concentration increases, the upconversion luminescence can be improved obviously. The upconversion luminescence mechanism is a two-photon process of energy transfer, excited state absorption, and energy back transfer. The emission intensity can be enhanced in the samples with high Yb{sup 3+} concentration, since the absorption for the incident laser and the energy transfer efficiency are increased, and the nonradiative relaxation probability is reduced. The light color referring to the ratio for red to green emissions can be tuned by Yb{sup 3+} concentration. Ho{sup 3+}/Yb{sup 3+} co-doped La{sub 2}O{sub 3}–TiO{sub 2}–ZrO{sub 2} glasses show promising comprehensive properties and are helpful to speed the application of upconversion luminescence materials. - Highlights: • Ho{sup 3+}/Yb{sup 3+} doped titanate glasses are prepared by containerless processing. • The effects of Yb{sup 3+} on thermal and mechanical properties have been studied. • High concentration of Yb{sup 3+} is favorable to upconversion luminescence. • The mechanisms are energy transfer, excited state absorption, energy back transfer.

  5. A new method of discriminating different types of post-Archean ophiolitic basalts and their tectonic significance using Th-Nb and Ce-Dy-Yb systematics

    Institute of Scientific and Technical Information of China (English)

    Emilio Saccani

    2015-01-01

    -derived components (nascent forearc sub-settings) characterized by MTBs and depleted-MORBs. Two additional discrimination diagrams are proposed: (1) a Dy-Yb diagram is used for discriminating boninite and IAT basalts; (2) a Ce/Yb-Dy/Yb diagram is used for discriminating G-MORBs and normal MORBs. The proposed method may effec-tively assist in recovering the tectonic affinity of ancient ophiolites, which is fundamental for establishing the geodynamic evolution of ancient oceanic and continental domains, as well as orogenic belts.

  6. A new method of discriminating different types of post-Archean ophiolitic basalts and their tectonic significance using Th-Nb and Ce-Dy-Yb systematics

    Directory of Open Access Journals (Sweden)

    Emilio Saccani

    2015-07-01

    -derived components (nascent forearc sub-settings characterized by MTBs and depleted-MORBs. Two additional discrimination diagrams are proposed: (1 a Dy-Yb diagram is used for discriminating boninite and IAT basalts; (2 a Ce/Yb-Dy/Yb diagram is used for discriminating G-MORBs and normal MORBs. The proposed method may effectively assist in recovering the tectonic affinity of ancient ophiolites, which is fundamental for establishing the geodynamic evolution of ancient oceanic and continental domains, as well as orogenic belts.

  7. Standard energies of combustion and standard enthalpies of formation for the complexes RE (Et2dtc)3(phen) (RE=Ho, Er, Tm, Yb, Lu)

    Institute of Scientific and Technical Information of China (English)

    WEI Qing; CHEN Sanping; YANG Xuwu; GAO Shengli; SHI Qizhen

    2005-01-01

    The treatment of RECl3·xH2O (RE = Ho, Er, Tm, Yb, Lu; x = 3-4) with sodium diethyldithiocarbamate RE(Et2dtc)3(phen). IR spectra of the complexes showed that RE3+ coordinated to two sulfur atoms in NaEt2dtc and two ritrogen atoms in o-phen. The constant-volume energies of combustion of the complexes have been determined by a precise rotating-bomb calorimeter at 298.15 K. The standard enthalpies of combustion and standard enthalpies of formation were calculated.

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

    Science.gov (United States)

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

    2007-04-01

    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 .

  9. Evidence for SrHo2O4 and SrDy2O4 as model J1-J2 zigzag chain materials

    DEFF Research Database (Denmark)

    Fennell, A.; Pomjakushin, V. Y.; Uldry, A.

    2014-01-01

    Neutron diffraction and inelastic spectroscopy is used to characterize the magnetic Hamiltonian of SrHo2O4 and SrDy2O4. Through a detailed computation of the crystal-field levels we find site-dependent anisotropic single-ion magnetism in both materials, and diffraction measurements show the prese...

  10. Effect of the Yb3+ Concentration in Up-Conversion and Electrical Properties of Ho3+/Yb3+ Co-doped (0.94Na0.5Bi0.5TiO3-0.06BaTiO3) Ceramics

    Science.gov (United States)

    Liu, Qian; Li, Yanxia; Li, Jun; Chai, Xiaona; Zhao, Haifeng; Wang, Xusheng; Yao, Xi

    2016-07-01

    Ho3+/Yb3+ co-doped 0.94Na0.5Bi0.5TiO3-0.06BaTiO3 (NBT-BT:Ho3+/Yb3+) ceramics were synthesized by solid-state reaction and characterized by x-ray diffraction (XRD), luminescent, dielectric, ferroelectric and piezoelectric measurements. The XRD diffraction data showed that all the ceramics were single phase with a perovskite structure. Bright green up-conversion (UC) emission bands (545 nm) and weak red UC emission bands (660 nm) corresponded to the transitions from (5F4, 5S2) → 5I8 and 4I5 → 5I8, respectively. Furthermore, optimized UC emission intensity was observed in the NBT-BT:0.005Ho3+/0.03Yb3+ samples. The thermal behavior of UC emission in the ceramics was also investigated and the maximum sensitivity based on fluorescence intensity ratio (FIR) technology was approximately 0.0042 K-1 at 100 K. Moreover, relatively good dielectric properties ( ɛ = 4475) and ferroelectric properties ( P r = 32 μ/cm2 and E c = 37 kV) were obtained in NBT-BT:0.005Ho3+/0.005Yb3+. As a multi-functional material, NBT-BT:Ho3+/Yb3+ ceramics may be useful in electro-optical devices.

  11. Temperature induced upconversion behaviour of Ho{sup 3+}-Yb{sup 3+} codoped yttrium oxide films prepared by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Anurag, E-mail: anuragpandey439@gmail.com [Department of Physics, University of the Free State, P. O. Box 339, Bloemfontein 9300 (South Africa); Kumar, Vinod, E-mail: vinod.phy@gmail.com [Department of Physics, University of the Free State, P. O. Box 339, Bloemfontein 9300 (South Africa); Photovoltaic Laboratory, Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi, 110016 (India); Kroon, R.E. [Department of Physics, University of the Free State, P. O. Box 339, Bloemfontein 9300 (South Africa); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, P. O. Box 339, Bloemfontein 9300 (South Africa)

    2016-07-05

    Pulsed laser deposited Ho{sup 3+}-Yb{sup 3+} codoped yttrium oxide films were grown on silicon substrates in vacuum at different substrate temperatures (373, 573, 773 and 973 K). The deposited films have shown a phase transition on increasing the substrate temperature, as confirmed by the X-ray diffraction analysis. The grain distribution and surface roughness of the deposited thin films have been estimated by atomic force microscopy measurements. In the optical properties study upconversion luminescence at 547, 656 and 758 nm was revealed upon 980 nm excitation. 773 K was found to be the best substrate temperature owing to the thickest deposited layer, as indicated by Auger depth profile analysis of the prepared films. A non-tunable bright green upconversion emission due to the involvement of a two photon process was established and a possible excitation-emission mechanism is explained by using an energy level diagram of the dopant ions. - Highlights: • Good quality PLD films of Ho{sup 3+}-Yb{sup 3+} codoped Y{sub 2}O{sub 3} were obtained. • Near-infrared to visible frequency upconversion emissions have been observed. • Bright green upconversion emission was obtained. • Absorption of two pump photons was responsible to achieve the observed emission.

  12. Magnetic fluctuations on TR{sub 3}Ba{sub 5}Cu{sub 8}O{sub δ} (TR=Ho, Y and Yb) superconducting system

    Energy Technology Data Exchange (ETDEWEB)

    Supelano, G.I., E-mail: ivan.supelano@uptc.edu.co [Grupo de Superficies Electroquímica y Corrosión, Universidad Pedagógica y Tecnológica de Colombia (Colombia); Sarmiento Santos, A. [Grupo de Superficies Electroquímica y Corrosión, Universidad Pedagógica y Tecnológica de Colombia (Colombia); Parra Vargas, C.A. [Grupo de Física de Materiales, Universidad Pedagógica y Tecnológica de Colombia (Colombia)

    2014-12-15

    In this work, we report the production of TR{sub 3}Ba{sub 5}Cu{sub 8}O{sub δ} (TR=Ho, Y and Yb) superconducting system using a usual solid state reaction method. The irreversibility line and the analysis of magnetization fluctuations for TR{sub 3}Ba{sub 5}Cu{sub 8}O{sub δ} (TR=Ho, Y and Yb) system were investigated. The curves of magnetization ZFC–FC were measured in magnetic fields of the 100–4000 Oe to obtain the values for T{sup ⁎} and T{sub C} temperatures. The penetration depth and the coherence length parameters as a function of the applied magnetic field were obtained. The data of the magnetization excess ΔM(T, H) was analyzed from the curves of magnetization as a function of logarithm of applied field for different values of temperature in the corresponding range. The Bulavskii, Ledvij and Kogan theory was employed for this purpose which considers fluctuations effects in the free energy and into the equilibrium magnetization.

  13. Highly sensitive and selective cartap nanosensor based on luminescence resonance energy transfer between NaYF4:Yb,Ho nanocrystals and gold nanoparticles.

    Science.gov (United States)

    Wang, Zhijiang; Wu, Lina; Shen, Baozhong; Jiang, Zhaohua

    2013-09-30

    Fluorescent detection is an attractive method for the detection of toxic chemicals. However, most chemosensors that are currently utilized in fluorescent detection are based on organic dyes or quantum dots, which suffer from instability, high background noise and interference from organic impurities in solution, which can also be excited by UV radiation. In the present research, we developed a novel NaYF4:Yb,Ho/Au nanocomposite-based chemosensor with high sensitivity (10 ppb) and selectivity over competing analytes for the detection of the insecticide cartap. This nanosensor is excited with a 970-nm laser instead of UV radiation to give an emission peak at 541 nm. In the presence of cartap, the nanocomposites aggregate, resulting in enhanced luminescence resonance energy transfer between the NaYF4:Yb,Ho nanocrystals and the gold nanoparticles, which decreases the emission intensity at 541 nm. The relative luminescence intensity at 541 nm has a linear relationship with the concentration of cartap in the solution. Based on this behavior, the developed nanosensor successfully detected cartap in farm produce and water samples with satisfactory results.

  14. Structural, magnetic and electronic transport studies of RAgSn2 compounds (R = Y, Tb, Dy, Ho and Er) with Cu3Au-type

    Indian Academy of Sciences (India)

    L Romaka; V V Romaka; I Lototska; A Szytula; B Kuzhel; A Zarzycki; E K Hlil; D Fruchart

    2013-12-01

    RAgSn2 compounds, where R = Y, Tb, Dy, Ho and Er, were synthesized by arc-melting and subsequent annealing at 870 K. The formation of cubic phases with Cu3Au-type structure (space group $\\bar{3}$) was studied. Magnetic property measurements showed that in paramagnetic state, the compounds with magnetic rareearth atoms are Curie–Weiss paramagnets and order antiferromagnetically at low temperatures. YAgSn2 is a Pauli paramagnet in 100–300 K temperature range. The electrical properties of RAgSn2 compounds were investigated by means of electrical resistivity and Seebeck coefficient measurements in 4.2–300 K temperature range. All investigated compounds exhibit metallic type of conductivity. Electronic structure calculations based on full potential linearized augmented plane wave (FLAPW)method is also carried out to probe themagnetic and electronic structures of RAgSn2 compounds. Comparisons between experimental data and calculations are discussed.

  15. Full potential calculations and atom in molecule analysis of the bonding properties of perovskites Borides XRh3B (X=Dy, Ho, Er

    Directory of Open Access Journals (Sweden)

    Ouahrani T.

    2013-03-01

    Full Text Available ab initio calculations were performed for the cubic perovskites Borides XRh3B, (X=Dy, Ho, Er. In this work, we have used the augmented plane-wave plus local orbital method to compute the equilibrium structural parameters and electronic structure of densities of states, as well as for the first time, prediction of the thermo-elastic properties of these crystals are presented. The chemical bonding of these compounds has been investigated by using of topological analyses grounded in the theory of atoms in molecules (AIM. All of the electron density critical points in the unit cell were systematically calculated in order to calculate basins interaction of each atoms and give exact classification of the bonding character.

  16. New Materials Derived from Ybco: CrSr2RECu2O8 (RE = La, Pr, Nd, Eu, Gd, Tb, Dy, Y, Ho, Er, Lu).

    Science.gov (United States)

    Ruiz-Bustos, Rocío; Aguirre, Myriam H; Alario-Franco, Miguel A

    2005-05-02

    Eleven new oxides, derived from yttrium barium copper oxide by replacing the square-planar copper [Cu-O4] of the basal plane of the triple perovskite-based structure with octahedral Cr(IV), have been prepared at high pressure and temperature. Their crystal structures have been determined, and their complex microstructure has been established by means of high-resolution electron microscopy and electron diffraction. The materials have a general formula of CrSr2RECu2O8 (RE = La, Pr, Nd, Eu, Gd, Tb, Dy, Y, Ho, Er, and Lu); they are tetragonal, show the symmetry of space group P4/mmm, and do not appear to be superconducting.

  17. Spectral intensities for the Cs{sub 2}NaDyCl{sub 6} and Cs{sub 2}NaHoCl{sub 6} systems

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo, Roberto; Navarro, Gustavo [Universidad Mayor, Manuel Montt 367, Santiago (Chile); Soto-Bubert, Andres [Universidad San Sebastian, Ernesto Pinto Lagarrigue 47, Santiago (Chile)], E-mail: roberto.acevedo@umayor.cl

    2008-11-01

    The main goal of this research work is to rationalize the rich vibronic structure of two lanthanide type crystals, such as Cs{sub 2}NaDyCl{sub 6} and Cs{sub 2}NaHoCl{sub 6}, which belongs to the space group Fm3m(O{sub h}{sup 5}). These systems are known to be highly relativistic and as a consequence, major corrections to previous calculation models, are due to be taken into account so as to rationalize the observed spectral intensities. Our emphasis has been placed upon both the origin and Nature of the physical model to be employed as well as on the strategy to be followed in order to improve our current understanding of the intensity mechanism with reference to general radiative transitions for complex systems, in the solid state physics.

  18. Electronic structure of RSn1.1Ge0.9 (R = Dy, Ho) ternary compounds: Band calculation and optical properties

    Science.gov (United States)

    Knyazev, Yu. V.; Lukoyanov, A. V.; Kuz'min, Yu. I.; Gupta, S.; Suresh, K. G.

    2017-09-01

    The results of investigations of the electronic structure and optical properties of the compounds DySn1.1Ge0.9 and HoSn1.1Ge0.9 are presented. Our spin-polarized calculations of the electronic structure are carried out in the local spin density approximation with correction for strong electronic correlations (LSDA+U method) in the 4f shell of the rare-earth ion. In the wavelength range 0.22-15 μm, the optical constants of the intermetallic compounds were measured by the ellipsometric method, and a number of spectral and electronic characteristics are determined. Based on the calculated densities of states, the structural features of the optical conductivity in the region of interband light absorption are interpreted.

  19. Optical properties and energy-transfer frequency upconversion of Yb 3+-sensitized Ho 3+- and Tb 3+-doped lead-cadmium-germanate glass and glass ceramic

    Science.gov (United States)

    Gouveia-Neto, Artur S.; Afonso, Antônio C. M.; Nascimento, Jehan F.; Costa, Ernande B.; Bueno, Luciano A.; Messaddeq, Younes; Ribeiro, Sidney J. L.

    2006-02-01

    In this report we investigate the optical properties and energy-transfer upconversion luminescence of Ho 3+- and Tb 3+/Yb 3+-codoped PbGeO 3-PbF II-CdF II glass-ceramic under infrared excitation. In Ho 3+/Yb 3+-codoped sample, green (545 nm), red(652 nm), and near-infrared(754 nm) upconversion luminescence corresponding to the 4S II( 5F 4) --> 5I 8, 5F 5 --> 5I 8, and 4S2( 5F 4) --> 5I 7, respectively, was readly observed. Blue (490 nm) signals assigned to the 5F II ,3 --> 5I 8 transition was also detected. In the Tb 3+/Yb 3+ system, bright UV-visible emission around 384, 415, 438, 473-490, 545, 587, and 623 nm, identified as due to the 5D 3( 5G 6) --> 7F J(J=6,5,4) and 5D 4--> 7F J(J=6,5,4,3) transitions, was measured. The comparison of the upconversion process in glass ceramic and its glassy precursor revealed that the former samples present much higher upconversion efficiencies. The dependence of the upconversion emission upon pump power, and doping contents was also examined. The results indicate that successive energy-transfer between ytterbium and holmium ions and cooperative energy-transfer between ytterbium and terbium ions followed by excited-state absorption are the dominant upconversion excitation mechanisms herein involved. The viability of using the samples for three-dimensional solid-state color displays is also discussed.

  20. Structure, upconversion photoluminescence, and dielectric properties of Ho{sup 3+}- and Yb{sup 3+}-codoped tetragonal tungsten bronze Sr{sub 4}La{sub 2}Ti{sub 4}Nb{sub 6}O{sub 30}

    Energy Technology Data Exchange (ETDEWEB)

    Wei, T., E-mail: weitong.nju@gmail.com [College of Science, Civil Aviation University of China, Tianjin 300300 (China); Li, C.P. [School of Electronics Information Engineering, Tianjin Key Laboratory of Film Electronic & Communication Devices, Tianjin University of Technology, Tianjin 300384 (China); Zhou, Q.J.; Li, Z.P.; Li, P.; Wu, J.; Yang, X.F. [College of Science, Civil Aviation University of China, Tianjin 300300 (China)

    2015-04-15

    Highlights: • TTB-type SLTN: Ho-Ybx with space group P4/mbm was determined. • UC photoluminescence of SLTN: Ho-Ybx ceramics was first reported. • Bright UC green emission was observed at room temperature. • Two-photon energy transfer process was confirmed for the UC processes. • Temperature stability of dielectric permittivity was improved for SLTN: Ho-Ybx. - Abstract: Ho{sup 3+}- and Yb{sup 3+}-codoped Sr{sub 4}La{sub 2}Ti{sub 4}Nb{sub 6}O{sub 30} (Sr{sub 4}La{sub 1.94–x}Ho{sub 0.06}Yb{sub x}Ti{sub 4}Nb{sub 6}O{sub 30}, abbreviated as SLTN: Ho-Ybx) ceramics have been synthesized, and their structural, up-conversion (UC) photoluminescence, and dielectric properties have been carefully investigated. Through Rietveld structural refinement, SLTN: Ho-Ybx samples are determined as single tetragonal tungsten bronze (TTB) phase with space group P4/mbm in which larger Sr{sup 2+} ions fill the A{sub 2}-sites, relative smaller La{sup 3+}, Ho{sup 3+}, and Yb{sup 3+} ions occupy the A{sub 1}-sites, while Ti{sup 4+} and Nb{sup 4+} ions fill the B-sites. Under 980 nm near infrared (NIR) excitation, bright UC green emission, relatively weak red and near-infrared (NIR) emissions, originating from {sup 5}F{sub 4}/{sup 5}S{sub 2} → {sup 5}I{sub 8}, {sup 5}F{sub 5} → {sup 5}I{sub 8}, and {sup 5}F{sub 4}/{sup 5}S{sub 2} → {sup 5}I{sub 7} transitions of Ho{sup 3+} ions, are confirmed for SLTN: Ho-Ybx. Two-photon energy transfer process is proved through pumping laser power dependence of emission intensity measurement. Furthermore, the influence of Ho{sup 3+}- and Yb{sup 3+}- ions on the dielectric properties of SLTN: Ho-Ybx is also investigated and the temperature stability of dielectric permittivity is improved.

  1. Features of magnetic and thermal properties of R(Co1-xFex)2 (x≤0.16) quasibinary compounds with R=Dy, Ho, Er

    Science.gov (United States)

    Anikin, Maksim; Tarasov, Evgeniy; Kudrevatykh, Nikolay; Inishev, Aleksander; Semkin, Mikhail; Volegov, Aleksey; Zinin, Aleksander

    2016-11-01

    In this work the results of measurements of high field susceptibility, paraprocess susceptibility and thermal properties of R(Co1-xFex)2 intermetallic compounds (R=Dy, Ho, Er and x=(0-0.16)) are presented (heat capacity and magnetocaloric effect (MCE)). A magnetic structure of the Ho(Co0.88Fe0.12)2 at 293 K and 78 K was studied by neutron powder diffraction. Some peculiarities of a high-field susceptibility were revealed at low temperatures and around the Curie point (TC). In temperature range lower than TC by (100-150) K, magnetic contributions to a zero-field heat capacity were found. Studying MCE in wide temperatures range, the large change of the entropy magnetic contribution (°S) was observed which correlates with °T phenomenon. In particular, for the Er(Co0.84Fe0.16)2 compound the °S value at low temperatures is six times higher than that at Curie point. The possible reasons of such behavior were discussed.

  2. White light generation controlled by changing the concentration of silver nanoparticles hosted by Ho{sup 3+}/Tm{sup 3+}/Yb{sup 3+} doped GeO{sub 2}–PbO glasses

    Energy Technology Data Exchange (ETDEWEB)

    Camilo, Mauricio E. [Faculdade de Tecnologia de São Paulo (FATEC-SP), CEETEPS/UNESP, São Paulo, SP (Brazil); Departamento de Engenharia de Sistemas Eletrônicos, Escola Politécnica da USP, São Paulo, SP (Brazil); Silva, Elton de O.; Kassab, Luciana R.P. [Faculdade de Tecnologia de São Paulo (FATEC-SP), CEETEPS/UNESP, São Paulo, SP (Brazil); Garcia, José A.M. [Faculdade de Tecnologia de São Paulo (FATEC-SP), CEETEPS/UNESP, São Paulo, SP (Brazil); Departamento de Engenharia de Sistemas Eletrônicos, Escola Politécnica da USP, São Paulo, SP (Brazil); Araújo, Cid B. de, E-mail: cid@df.ufpe.br [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil)

    2015-09-25

    Highlights: • Successful fabrication of Ho{sup 3+}–Tm{sup 3+}–Yb{sup 3+} doped lead–germanate glasses containing silver nanoparticles. • Efficient color control of Ho{sup 3+}–Tm{sup 3+}–Yb{sup 3+} doped glass by changing the concentration of silver nanoparticles. • Surface plasmon enhanced multicolor upconversion emission in Ho{sup 3+}–Tm{sup 3+}–Yb{sup 3+} doped lead–germanate glass. • White light generation due to the presence of silver nanoparticles. - Abstract: Frequency upconversion (UC) experiments were performed with GeO{sub 2}–PbO glasses, containing silver nanoparticles (NPs), doped with holmium (Ho{sup 3+}), thulium (Tm{sup 3+}) and ytterbium (Yb{sup 3+}) ions. The samples were excited using a continuous-wave diode laser operating at 980 nm. The UC intensities and the colors of the samples were controlled by changing the concentrations of the rare-earth ions (REI) and the silver NPs nucleated inside the samples. The colors observed spanned the visible range from the red–yellow to the blue. For a particular combination of silver NPs and REI concentrations it was obtained white light generation corresponding to the CIE coordinates X = 0.33 and Y = 0.33.

  3. Thermal decomposition of Ln(C2H5CO2)3·H2O (Ln = Ho, Er, Tm and Yb)

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude

    2012-01-01

    The thermal decomposition of Ho(III), Er(III), Tm(III) and Yb(III) propionate monohydrates in argon was studied by means of thermogravimetry (TG), differential thermal analysis (DTA), IR-spectroscopy and X-ray diffraction (XRD). Dehydration takes place around 90 °C. It is followed by the decompos...

  4. Preparation and up-conversion characterization of CaF{sub 2}:Yb{sup 3+}, Ho{sup 3+}/BaF{sub 2}:Yb{sup 3+}, Ho{sup 3+} co-doped glasses and glass–ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Zhao-xia, E-mail: luckyxia2007@126.com; Li, Hang-xin; Xue, Zhao-lu; Wang, Mei-han; Hu, Xiao-dan; Wang, Shao-hong

    2015-08-15

    Highlights: • New oxyfluoride tellurite glasses were prepared successfully. • CaF{sub 2} and BaF{sub 2} nano crystals were formed by heat treatment. • Up-conversion emission properties and mechanism were investigated. - Abstract: Oxyfluoride tellurite glasses with compositions of TeO{sub 2}–Al{sub 2}O{sub 3}–CaF{sub 2}/BaF{sub 2}–NaF–YbF{sub 3}–xHoF{sub 3} (x = 0.1, 0.3, 0.5, 1.0, 1.5, 2.0 mol%) were prepared by conventional melt-quenching method. Effect of heat-treatment schedules on crystallization behavior and microstructure were analyzed by differential scanning caborimetry, X-ray diffraction, infrared spectra and scanning electron microscopy. Cubic CaF{sub 2} and BaF{sub 2} nano-crystal phases were formed by controlling heat-treatment schedules. Up-conversion emission properties and mechanism of Yb{sup 3+} and Ho{sup 3+} ions in glasses and glass–ceramics were investigated. The green and red up-conversion emissions were observed under 980 nm LD excitation. Up-conversion luminescence intensity in glasses was obvious higher than that in glass–ceramics. And there existed concentration quenching effect among Ho{sup 3+} ions resulted from cross-relaxation.

  5. Upconversion luminescence in BaYF{sub 5}, BaGdF{sub 5} and BaLuF{sub 5} nanocrystals doped with Yb{sup 3+}/Ho{sup 3+}, Yb{sup 3+}/Er{sup 3+} or Yb{sup 3+}/Tm{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Grzyb, Tomasz, E-mail: tgrzyb@amu.edu.pl [Department of Rare Earths, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań (Poland); Balabhadra, Sangeetha [Department of Physics, University of Aveiro, Campus Universitario de Santiago, 3810-193, Aveiro (Portugal); Przybylska, Dominika; Węcławiak, Mariusz [Department of Rare Earths, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań (Poland)

    2015-11-15

    Nanomaterials based on BaREF{sub 5} fluorides (where RE = Y, Gd and Lu), doped with lanthanide ions Yb{sup 3+}/Ln{sup 3+} (Ln{sup 3+} = Er, Ho or Tm) were synthesized by microwave assisted hydrothermal method. The method of synthesis, structural and morphological properties are reported and discussed. The products obtained showed visible upconversion luminescence excited by the laser light of wavelength of 975 nm as a consequence of energy transfer between Yb{sup 3+} and remaining Ln{sup 3+} dopant ions. Their spectroscopic properties were characterized on the basis of excitation and emission spectra. Also luminescence decays and emission power dependences are presented and analysed. The materials compared revealed differences in their structural properties, reflected in their spectroscopic characteristics. The most intense luminescence was recorded for BaLuF{sub 5} based materials which exhibited upconversion also as water colloids. - Highlights: • BaREF{sub 5} nanomaterials (RE = Y, Gd or Lu) were synthesized by hydrothermal method. • Upconversion in BaREF{sub 5}:Yb{sup 3+}, Ln{sup 3+} (Ln = Ho, Er, Tm) nanocrystals was compared. • Mechanism of upconversion was analysed.

  6. PRODUCCIÓN Y CARACTERIZACIÓN DEL NUEVO SISTEMA SUPERCONDUCTOR Yb0,5Ho0,5Ba2Cu3O7-d

    OpenAIRE

    Jully P. Peña; José Otálora; Davian Martinez; Jairo Roa; Carlos A. Parra

    2011-01-01

    Se reporta la caracterización del nuevo sistema superconductor Yb0,5Ho0,5Ba2Cu3O7-δ perteneciente a la familia de cupratos de alta temperatura TR123; el material fue producido utilizando el método de reacción de estado sólido (SSR) con una temperatura de sinterizado de 910 °C. Se muestra la caracterización morfológica referente al comportamiento granular utilizando la técnica de Microscopía electrónica de barrido (SEM); la caracterización estructural, se logra sometiendo la muestra a difracci...

  7. Structural and optical characterization of NaGdF{sub 4}: Ho{sup 3+}/Yb{sup 3+} UC nano-particles for lateral finger mark detections

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A., E-mail: ak.phy87@gmail.com; Tiwari, S. P.; Krishna, K. M.; Kumar, K. [Optical Materials and Bio-imaging Research Laboratory Department of Applied Physics, Indian School of mines, Dhanbad-826004 (India)

    2016-05-23

    Ho{sup 3+}/Yb{sup 3+} co-doped NaGdF{sub 4} up-conversion (UC) nano-particles were synthesized by thermal decomposition method. X-ray diffraction and FE-SEM image analysis were done to confirm the structure, morphology and determination of particle size. The UC emission spectra for as prepared as well as 100°C, 200°C, 300°C, 400°C, 800°C, 1000°C and 1200°C heated for 3h samples were recorded and there emission intensities were compared at a constant pump power of excitations 98.1 W/cm{sup 2}. The effect of emission intensity on decay time was also studied through focused and unfocused excitations. The synthesized material was successfully utilized in lateral finger mark detections on the glass substrate through powder dusting method.

  8. Magnetic and electrical studies of Ho0.9RE0.1CrO3 (RE = Gd and Yb multiferroics

    Directory of Open Access Journals (Sweden)

    Shubhra Mathur

    2016-09-01

    Full Text Available We report magnetic and electrical studies on multiferroic systems Ho0.9(RE0.1CrO3 where RE symbolizes rare earths like Gd and Yb. Solid state diffusion method has been used to synthesize the samples. Structural phase formation has been confirmed with the help of powder X-ray diffraction. Magnetization measurements show canted antiferromagnetic nature with a weak ferromagnetic phase. Néel temperature for Cr3+–Cr3+ ordering shifts to higher side with increasing radii of rare earth cations. Frequency (100 Hz to 1 MHz and temperature (300–650 K dependent resistivity measurements are suggestive of semiconducting nature of the samples.

  9. Suppression of the superconducting transition of RFeAsO1-xFx ( R=Tb , Dy, and Ho)

    Science.gov (United States)

    Rodgers, Jennifer A.; Penny, George B. S.; Marcinkova, Andrea; Bos, Jan-Willem G.; Sokolov, Dmitry A.; Kusmartseva, Anna; Huxley, Andrew D.; Attfield, J. Paul

    2009-08-01

    A suppression of superconductivity in the late rare-earth RFeAsO1-xFx materials is reported. The maximum critical temperature (Tc) decreases from 51 K for R=Tb to 36 K for HoFeAsO0.9F0.1 , which has been synthesized under 10 GPa pressure. This suppression is driven by a decrease in the Fe-As-Fe angle below an optimum value of 110.6° , as the angle decreases linearly with unit-cell volume (V) across the RFeAsO1-xFx series. A crossover in electronic structure around this optimum geometry is evidenced by a change in sign of the compositional dTc/dV , from negative values for previously reported large R materials to positive for HoFeAsO0.9F0.1 .

  10. Charge transfer excitation of trivalent rare earth ions Sm/sup 3+/, Eu/sup 3+/, Gd/sup 3+/, Ho/sup 3+/, Er/sup 3+/ and Yb/sup 3+/ emission in BaFCl crystals

    Energy Technology Data Exchange (ETDEWEB)

    Su, M.Z.; Sun, X.P.

    1987-01-01

    The charge transfer type excitation spectra of trivalent rare earth ions Sm/sup 3+/, Eu/sup 3+/, Gd/sup 3+/, Ho/sup 3+/, Er/sup 3+/ and Yb/sup 3+/ emission in BaFCl crystals have been studied. The charge transfer type emissions of Ho/sup 3+/, Er/sup 3+/ and Yb/sup 3+/ in BaFCl have also been observed in addition to that of Eu/sup 3+/. The energy of charge transfer band of these RE/sup 3+/ ions were estimated experimentally and also calculated by Jorgensen's refined electron spin-pairing energy theory. Both the experimental and calculated values coincide well.

  11. Near infrared and visible luminescence from xerogels covalently grafted with lanthanide [Sm(3+), Yb(3+), Nd(3+), Er(3+), Pr(3+), Ho(3+)] β-diketonate derivatives using visible light excitation.

    Science.gov (United States)

    Sun, Lining; Qiu, Yannan; Liu, Tao; Zhang, Jin Z; Dang, Song; Feng, Jing; Wang, Zhijuan; Zhang, Hongjie; Shi, Liyi

    2013-10-09

    A series of ternary lanthanide β-diketonate derivatives covalently bonded to xerogels (named as Ln-DP-xerogel, Ln = Sm, Yb, Nd, Er, Pr, Ho) by doubly functionalized alkoxysilane (dbm-Si) was synthesized in situ via a sol-gel process. The properties of these xerogel materials were investigated by Fourier-transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), diffuse reflectance (DR) spectroscopy, thermogravimetric analyses, and fluorescence spectroscopy. The data and analyses suggest that the lanthanide derivatives have been covalently grafted to the corresponding xerogels successfully. Of importance here is that, after excitation with visible light (400-410 nm), the xerogels all show characteristic visible (Sm(3+)) as well as near-infrared (NIR; Sm(3+), Yb(3+), Nd(3+), Er(3+), Pr(3+), Ho(3+)) luminescence of the corresponding Ln(3+) ions, which is attributed to the energy transfer from the ligands to the Ln(3+) ions via an antenna effect. Exciting with visible light is advantageous over UV excitation. Furthermore, to the best of our knowledge, it is the first observation of NIR luminescence with visible light excitation from xerogels covalently bonded with the Sm(3+), Pr(3+), and Ho(3+) derivatives. Compared to lanthanide complexes (Ln = Er, Nd, Yb) functionalized periodic mesoporous organosilica (PMO) materials that exhibit similar optical properties reported in our previous work, the Ln-DP-xerogel (Ln = Sm, Yb, Nd, Er, Pr, Ho) in this case offer advantages in terms of ease of synthesis and handling and potentially low cost for emerging technological applications. Development of near-infrared luminescence of the lanthanide materials with visible light excitation is of strong interest to emerging applications such as chemosensors, laser systems, and optical amplifiers.

  12. Synthesis of white light LaF{sub 3}: 20%Yb{sup 3+}, 0.1%Ho{sup 3+}, 1%Tm{sup 3+} single nanocrystals by precipitated transformation method

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Sha; Wang, Xigui [College of Chemistry and Environment Science, Inner Mongolia Normal University, 81 Zhaowuda Road, Hohhot 010022 (China); De, Gejihu, E-mail: degjh@imnu.edu.cn [College of Chemistry and Environment Science, Inner Mongolia Normal University, 81 Zhaowuda Road, Hohhot 010022 (China); Inner Mongolia Key Laboratory for Green Catalysis, 81 Zhaowuda Road, Hohhot 010022 (China)

    2014-08-01

    In this article, we describe the production of uniform hexagonal phase LaF{sub 3}:20%Yb{sup 3+}, 0.1%Ho{sup 3+}, 1%Tm{sup 3+} (LFYHT) monodisperse nanoparticles through a hydrothermal precipitated transformation reaction using La(OH){sub 3}: 20%Yb{sup 3+}, 0.1%Ho{sup 3+}, 1%Tm{sup 3+} (LOYHT) nanorods as parent materials. The trivalent rare earth hydroxides were hydrothermally prepared at 180 °C. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) analysis showed the LFYHT nanoparticles to have an average size of 10 nm and diameters similar to those of LOYHT nanorods. The upconversion spectra of the sample were measured using a fluorescence spectrophotomere with single-wavelength diode lasers (980 nm) at room temperature. Red, green, and blue emissions were associated with the synthesized sample. The calculated color coordinates demonstrated that white light can be produced in a wide range of pumping powers. - Highlights: • We describe the production of uniform hexagonal phase LaF{sub 3}:20%Yb{sup 3+}, 0.1%Ho{sup 3+}, 1%Tm{sup 3+} monodisperse nanoparticles through a hydrothermal precipitated transformation method. • Powder X-ray diffraction, transmission electron microscopy and high-resolution transmission electron microscopy analysis showed the LaF{sub 3}:20%Yb{sup 3+}, 0.1%Ho{sup 3+}, 1%Tm{sup 3+} nanoparticles to have an average size of 10 nm. • The white upconversion light can be producted in a wide range of pumping powers.

  13. Synthesis and Characterization of Ethylthioethylcyclopentadienyl Organolanthanide Complexes:Cp2Th LnCl (Ln=Gd, Dy), Cp2LnCpTh (Ln=Yb, Sm, Dy, Y) and Cp2ThErCl2·2THF

    Institute of Scientific and Technical Information of China (English)

    ZHU Ming朱铭; ZHANG Li-Bei张丽蓓; CHEN Ying-Hua陈应华; ZHOU Xi-Geng周锡庚; CAI Rui-Fang蔡瑞芳; WENG Lin-Hong翁林红

    2004-01-01

    Six new ethylthioethylcyclopentadienyl-containing organolanthanide complexes Cp2Th LnCl [Ln=Gd (1), Dy (2)]and Cp2LnCpTh [Cp=C5H5, Ln=Yb (3), Sm (4), Dy (5), Y (6)] were synthesized by the reaction of ethylthioethylcyclopentadienyl (CpTh) sodium salt with LnC13 or Cp2LnCl in THF. Complexes 1-6 were characterized by elemental analyses, infrared and mass spectroscopies. The molecular structures of complexes 1-3 were also determined by the X-ray single crystal diffraction. The results show that the side-chain sulfur atom on the ethylthioethylcyclopentadienyl ring can form intramolecular chelating coordination to the central lanthanide ion, improving the stability of organolanthanide complexes and reducing the number of coordinated THF molecules.

  14. Rotational and translational distortions of the crystal structure of the Sr{sub 2}HrRuO{sub 6} (Hr = Ho, Dy, Gd, Eu) complex perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Triana, C.A., E-mail: ctrianae@unal.edu.co [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, A.A. 5997, Bogotá D.C. (Colombia); Landínez Téllez, D.A. [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, A.A. 5997, Bogotá D.C. (Colombia); Roa-Rojas, J., E-mail: jroar@unal.edu.co [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, A.A. 5997, Bogotá D.C. (Colombia)

    2013-05-15

    Sr{sub 2}HrRuO{sub 6} (Hr = Ho, Dy, Gd, Eu) complex perovskites were synthesized through the high-temperature solid-state reaction method, and their crystal structures were analyzed in detail as a function of the Hr-cation ionic radius. Results of powder XRD pattern measurement and Rietveld analysis of the experimental profiles show that the Sr{sub 2}HrRuO{sub 6} compounds crystallize in a monoclinic distorted perovskite-like structure, P2{sub 1}/n (#14) space group, where the unit cell parameters are related to the primitive unit cell a{sub p} by a≈√(2)a{sub p}, b≈√(2)a{sub p} and c ≈ 2a{sub p}. The structures show an alternate distribution of the Ru{sup 5+} (2d: 0.5, 0, 0) and Hr{sup 3+} (2c: 0, 0.5, 0) making up RuO{sub 6} and HrO{sub 6} octahedra alternatively arranged in two interleaving fcc sublattices, where the O(1), O(2), and O(3) ions are localized at the corner of the octahedral, while the Sr{sup 2+} is located at the A-site, occupying the cavities built by the corner-sharing octahedra with Wyckoff position 4e. Due to the existence of mismatched ionic sizes between the ionic radii of the Sr{sub 2}HrRuO{sub 6} compounds, the HrO{sub 6} and RuO{sub 6} octahedra are constrained to tilting around the [111]{sub c}, [001]{sub c}, and [110]{sub c} cubic directions so as to optimize the Sr–O inter-atomic bond lengths, tending to rotate the structure in order to fix the Ru{sup 5+} and Hr{sup 3+} ions on the M′ and M″ sites of the complex perovskites. The cell parameters a, b, and c, the inter-atomic bond angles, the inter-atomic bond lengths, and the tilting angles increase as the Hr-cation ionic radius increases. The mismatch that exists in the Sr{sub 2}HrRuO{sub 6} ionic radius produces a large distortion from the ideal cubic symmetry. The pure perovskite-like phase of Sr{sub 2}HrRuO{sub 6} is thermodynamically and kinetically stable at high temperatures above 1420 K, where it is entirely governed by the average size of the Hr{sup 3+} and Ru

  15. Magnetic hyperfine interactions on Cd sites of the rare-earth cadmium compounds R Cd (R =Ce , Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er)

    Science.gov (United States)

    Cavalcante, F. H. M.; Leite Neto, O. F. L. S.; Saitovitch, H.; Cavalcante, J. T. P. D.; Carbonari, A. W.; Saxena, R. N.; Bosch-Santos, B.; Pereira, L. F. D.; Mestnik-Filho, J.; Forker, M.

    2016-08-01

    This paper reports the investigation of the magnetic hyperfine field Bh f in a series of rare-earth (R ) cadmium intermetallic compounds R Cd and GdCd2 measured by perturbed angular correlation (PAC) spectroscopy using 111In/111Cd as probe nuclei at Cd sites as well as first-principles calculations of Bh f at Cd sites in the studied compounds. Vapor-solid state reaction of R metals with Cd vapor and the 111In radioisotope was found to be an appropriate route of doping rare-earth cadmium compounds with the PAC probe 111In/111Cd. The observation that the hyperfine parameters depend on details of the sample preparation provides information on the phase preference of diffusing 111In in the rare-earth cadmium phase system. The 111Cd hyperfine field has been determined in the compounds R Cd for the R constituents Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er, in several cases as a function of temperature. For most R constituents, the temperature dependence Bh f(T ) of 111Cd:R Cd is consistent with ferromagnetic order of the compound. DyCd, however, presents a remarkable anomaly: a finite magnetic hyperfine field is observed only in the temperature interval 35 K ≤ T ≤ 80 K which indicates a transition from ferromagnetic order to a spin arrangement where all 4 f -induced contributions to the magnetic hyperfine field at the Cd site cancel. First-principles calculation results for DyCd show that the (π , π , 0) antiferromagnetic configuration is energetically more favorable than the ferromagnetic. The approach used in the calculations to simulate the R Cd system successfully reproduces the experimental values of Bh f at Cd sites and shows that the main contribution to Bh f comes from the valence electron polarization. The de Gennes plot of the hyperfine field Bh f of 111Cd:R Cd vs the 4 f -spin projection (g -1 )J reflects a decrease of the strength of indirect 4 f -4 f exchange across the R series. Possible mechanisms are discussed and the experimental results indicate that

  16. Synthesis and up-conversion luminescence of Yb3+–Ho3+ co-doped Na(Y1.5Na0.5)F6 nanorods

    Indian Academy of Sciences (India)

    Yang Yi Zhang; Jing Quan Deng; Shou Chun Ni

    2013-08-01

    We present the optical up-conversion (UC) study for Yb3+–Ho3+ co-doped Na(Y1.5Na0.5)F6 nanorods synthesized by employing a facile hydrothermal method. Numbers of Ho3+ ion up-conversion emissions have been observed under 980 nm infrared diode laser excitation. Three UC emissions of interest, ultraviolet, violet and blue, are specially identified at 359, 387, 418 and 483 nm, corresponding to ${}^{5}G'_{5}/{}^{3}H_{6} \\rightarrow {}^{5}I_{8}, {}^{5}G_{4}/{}^{3}K_{7} \\rightarrow {}^{5}I_{8}, {}^{5}G_{5} \\rightarrow {}^{5}I_{8}$ and ${}^{5}F_{3}/{}^{5}F_{2}/{}^{3}K_{8} \\rightarrow {}^{5}I_{8}$ transitions, respectively. It is also found that the centre wavelength of blue UC emission shifts to 475 nm gradually as Ho3+ concentration decreases. Lastly, a brief analysis about UC mechanism is demonstrated according to the experimental results.

  17. Thermoelastic properties of ScB2, TiB2, YB4 and HoB4: Experimental and theoretical studies

    DEFF Research Database (Denmark)

    Waśkowska, A.; Gerward, Leif; Staun Olsen, J.

    2011-01-01

    modulus 180–200 GPa), while TiB2 may be classified as superhard (bulk modulus about 260 GPa). We report here first experimental and theoretical determinations of the bulk modulus for HoB4 (195(5) and 198.2 GPa, respectively), and first experimental values of the bulk modulus for ScB2 (196(2) GPa) and YB4...... (185(4) GPa). No pressure-induced phase transformations are observed in any of the above borides up to about 20 GPa. A continuous temperature-driven orthorhombic distortion is observed for HoB4 below 285 K. Values of the thermal expansion coefficient are reported for ScB2 and HoB4 at 293, 200 and 100 K...

  18. Synthesis, characterization, and in vitro evaluation of a radio-metal organic framework composed of in vivo generator {sup 166}Dy/{sup 166}Ho and DOTMP as a novel agent for bone marrow ablation

    Energy Technology Data Exchange (ETDEWEB)

    Vosoghi, Sara; Shirvani-Arani, Simindokht; Bahrami-Samani, Ali; Salek, Nafise; Mirerezaei, Ehsan; Jalilian, Amir Reza [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of)

    2016-07-01

    In this study, the MOF concept contributed to the preparation of a novel, bone-ablating agent composed of Cu(II) using the in vivo generator {sup 166}Dy/{sup 166}Ho and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid (DOTMP). The product was characterized (IR, elemental analysis: CHN, ICM-MS, PIXE, DLS, XRD) and quality-controlled (radio-thin layer chromatography (RTLC)). The stability and in vitro hydroxyapatite binding was checked up to one week at 37 C in human serum. Radio-MOF crystals and colloidal radio-MOF particles were obtained by varying the synthesizing conditions (including pH and temperature), and they had similar IR patterns and similar elemental analysis results. The estimated chemical formula was [1Lu-1Cu-1Cl-1DOTMP] for both. The final product was synthesized at pH = 8 while stirring at room temperature using {sup 166}Dy/{sup 166}Ho-nitrate, CuCl{sub 2}, and DOTMP (yield > 99%, RTLC). Dynamic light scattering (DLS) measurements showed particles in the size range of 60 to 100 nm for the resultant radio-MOF particles (RMP). In vitro binding experiments showed acceptable bone-seeking affinity of the prepared formula even after one week of storage in human serum at 37 C. Importantly, this is the first study of the use of the MOF concept to provide a highly-stable organometallic compound containing {sup 166}Dy/{sup 166}Ho in vivo generator for bone marrow ablation.

  19. High-pressure syntheses and characterization of the rare-earth fluoride borates RE{sub 2}(BO{sub 3})F{sub 3} (RE = Tb, Dy, Ho)

    Energy Technology Data Exchange (ETDEWEB)

    Hinteregger, Ernst; Pitscheider, Almut; Wurst, Klaus; Heymann, Gunter; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie; Enders, Michael [Innsbruck Univ. (Austria). Inst. fuer Pharmazie

    2013-11-15

    The new rare-earth fluoride borates RE{sub 2}(BO{sub 3})F{sub 3} (RE = Tb, Dy, Ho) were synthesized under high-pressure/high-temperature conditions of 1.5 GPa/1200 C for Tb{sub 2}(BO{sub 3})F{sub 3} and 3.0 GPa/900 C for Dy{sub 2}(BO{sub 3})F{sub 3} and Ho{sub 2}(BO{sub 3})F{sub 3} in a Walker-type multianvil apparatus from the corresponding rare-earth sesquioxides, rare-earth fluorides, and boron oxide. The single-crystal structure determinations revealed that the new compounds are isotypic to the known rare-earth fluoride borate Gd{sub 2}(BO{sub 3})F{sub 3}. The new rare-earth fluoride borates crystallize in the monoclinic space group P2{sub 1}/c (Z = 8) with the lattice parameters a = 16.296(3), b = 6.197(2), c = 8.338(2) A, {beta} = 93.58(3) for Tb{sub 2}(BO{sub 3})F{sub 3}, a = 16.225(3), b = 6.160(2), c = 8.307(2) A, {beta} = 93.64(3) for Dy{sub 2}(BO{sub 3})F{sub 3}, and a = 16.189(3), b = 6.124(2), c = 8.282(2) A, {beta} = 93.69(3) for Ho{sub 2}(BO{sub 3})F{sub 3}. The four crystallographically different rare-earth cations (CN = 9) are surrounded by oxygen and fluoride anions. All boron atoms form isolated trigonal-planar [BO{sub 3}]{sup 3-} groups. The six crystallographically different fluoride anions are in a nearly planar coordination by three rare-earth cations. (orig.)

  20. PRODUCCIÓN Y CARACTERIZACIÓN DEL NUEVO SISTEMA SUPERCONDUCTOR Yb0,5Ho0,5Ba2Cu3O7-d

    Directory of Open Access Journals (Sweden)

    Jully P. Peña

    2011-01-01

    Full Text Available Se reporta la caracterización del nuevo sistema superconductor Yb0,5Ho0,5Ba2Cu3O7-δ perteneciente a la familia de cupratos de alta temperatura TR123; el material fue producido utilizando el método de reacción de estado sólido (SSR con una temperatura de sinterizado de 910 °C. Se muestra la caracterización morfológica referente al comportamiento granular utilizando la técnica de Microscopía electrónica de barrido (SEM; la caracterización estructural, se logra sometiendo la muestra a difracción de rayos X (DRX y se obtienen los parámetros estructurales implementando el método de refinamiento Rietveld en el software GSAS, el material resulta poseer celdas unitarias ortorrómbicas tipo perovskita con un comportamiento superconductor que se evidencia en la curva de resistividad como función de la temperatura cuya derivada presenta un punto crítico en el valor correspondiente a la temperatura crítica Tc 92,61 K.

  1. Infrared and Raman spectra of tris(dipivaloylmethanato) lanthanides, Ln(thd)3 (Ln = La, Nd, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu)

    Science.gov (United States)

    Belova, Natalya V.; Sliznev, Valery V.; Christen, Dines

    2017-03-01

    The infrared and Raman vibrational spectra of the series of solid tris(dipivaloylmethanato) lanthanides, Ln(thd)3 (Ln = La, Nd, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu), have been recorded at room temperature over wide ranges (4000-50 cm-1 and 3500-80 cm-1, respectively). The experimental spectra obtained in the present study were successfully assigned based on the quantum chemical calculations (DFT/PBE0) performed for the monomer Ln(thd)3 molecules. The experimental vibrational spectra for all complexes studied are rather similar as are the theoretical simulations. The data analysis shows that the main contributions to vibrational modes arise from the vibrations of the ligand possessing practically the same geometry for all complexes. According to the calculation results the structure of the coordination polyhedron is increasingly distorted in the series from La(thd)3 to Lu(thd)3. Although the contributions of the polyhedron vibrations in vibrational modes are not predominant, there is rise in the frequencies associated with vibrations of the coordination polyhedron LnO6 in this series. This increase has been explained by the concept of lanthanide contraction.

  2. Sensitivity of magnetic properties to chemical pressure in lanthanide garnets Ln 3 A 2 X 3O12, Ln  =  Gd, Tb, Dy, Ho, A  =  Ga, Sc, In, Te, X  =  Ga, Al, Li

    Science.gov (United States)

    Mukherjee, P.; Sackville Hamilton, A. C.; Glass, H. F. J.; Dutton, S. E.

    2017-10-01

    A systematic study of the structural and magnetic properties of three-dimensionally frustrated lanthanide garnets Ln 3 A 2 X 3O12, Ln  =  Gd, Tb, Dy, Ho, A  =  Ga, Sc, In, Te, X  =  Ga, Al, Li is presented. Garnets with Ln  =  Gd show magnetic behaviour consistent with isotropic Gd3+ spins; no magnetic ordering is observed for T  ⩾  0.4 K. Magnetic ordering features are seen for garnets with Ln  =  Tb, Dy, Ho in the temperature range 0.4  Tb, Dy, Ho.

  3. Separation and Recycling for Rare Earth Elements by Homogeneous Liquid-Liquid Extraction (HoLLE) Using a pH-Responsive Fluorine-Based Surfactant

    OpenAIRE

    2015-01-01

    A selective separation and recycling system for metal ions was developed by homogeneous liquid-liquid extraction (HoLLE) using a fluorosurfactant. Sixty-two different elemental ions (e.g., Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, La, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Re, Rh, Ru, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tl, Tm, V, W, Y, Yb, Zn, and Zr) were examined. By changing pH from a neutral or alkaline solu...

  4. Croissance de fibres à gradient de concentration et analyse des processus dynamiques de transitions laser résonnantesdans Y203 dopé Er^{3+}, Yb^{3+} et Ho^{3+}

    Science.gov (United States)

    Laversenne, L.; Goutaudier, C.; Guyot, Y.; Cohen-Adad, M. Th.; Boulon, G.

    2002-06-01

    La croissance et l'exploitation de fibres à gradient de concentration de Y203 dopé par des ions terres rares permet d'étudier les processus dynamiques de transitions laser résonnantes des ions Yb^{3+}, Er^{3+} et Ho^{3+}. Plus particulièrement nous mettons en évidence et analysons les transferts d'énergie radiatifs (self trapping) responsables de l'allongement de la durée de vie expérimentale.

  5. Lasing in a Tm:Ho:Yb{sub 3}Al{sub 5}O{sub 12} crystal pumped into the {sup 3}H{sub 6} – {sup 3}F{sub 4} transition

    Energy Technology Data Exchange (ETDEWEB)

    Zavartsev, Yu D; Zagumennyi, A I; Kalachev, Yu L; Kutovoi, S A; Mikhailov, V A; Shcherbakov, I A [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2016-03-31

    A growth technology has been developed, and a Tm:Ho:Yb{sub 3}Al{sub 5}O{sub 12} laser crystal of high optical quality has been grown by Czochralski method. Its spectral and luminescent characteristics are studied. Lasing at a wavelength of 2100 nm is obtained under pumping into the absorption line on the {sup 3}H{sub 6} – {sup 3}F{sub 4} transition of the Tm{sup 3+} ion at a wavelength of 1678 nm. The slope and total (optical) efficiencies of the laser at an output power of up to 320 mW reach 41% and 30%, respectively. (lasers)

  6. Ho3+/Yb3+ co-doped TeO2-BaF2-Y2O3 glasses for ∼1.2 μm laser applications

    Science.gov (United States)

    Wang, Shunbin; Li, Chengzhi; Yao, Chuanfei; Jia, Shijie; Jia, Zhixu; Qin, Guanshi; Qin, Weiping

    2017-02-01

    Intense ∼1.2 μm fluorescence is observed in Ho3+/Yb3+ co-doped TeO2-BaF2-Y2O3 glasses under 915 nm laser diode excitation. The 1.2 μm emission can be ascribed to the transition 5I6→5I8 of Ho3+. With the introducing of BaF2, the content of OH in the glasses drops markedly, and the 1.2 μm emission intensity increases gradually as increasing the concentration percentage of BaF2. Furthermore, microstructured fibers based on the TeO2-BaF2-Y2O3 glasses are fabricated by using a rod-in-tube method, and a relative positive gain of ∼9.42 dB at 1175.3 nm is obtained in a 5 cm long fiber.

  7. Effects of Li+ ions on the enhancement of up-conversion emission in Ho3+-Yb3+ co-doped transparent glass-ceramics containing Ba2LaF7 nanocrystals

    Science.gov (United States)

    Li, Zhencai; Zhou, Dacheng; Yang, Yong; Gao, Yuan; Ren, Peng; Qiu, Jianbei

    2016-10-01

    The up-conversion (UC) emission of Ho3+-Yb3+ and Li+ co-doped transparent glass ceramics 45SiO2-15Al2O3-12Na2CO3-21BaF2-7LaF3-0.2HoF3-1YbF3-xLi2CO3 (x = 0, 0.5, 1, 2, 4 and 6 mol%) containing Ba2LaF7 nanocrystals were investigated. These glass ceramics samples were prepared using the conventional quenching techniques. The Ba2LaF7 nanocrystals precipitated from the glass matrix was confirmed by X-ray diffraction (XRD). Compared with the glass ceramics sample without Li+, the UC emission intensity of glass ceramics samples with Li+ were enhanced. It can be proved that the Li+ can affect the enhancement up-conversion (UC) emission. Particularly, the green UC emission intensity band centered at 546 nm was strongly increased twice with the concentration of Li+ increasing up to 4 mol%. Through the comparison and analysis of the energy graph, it was shown that the 5F4/5S2→5I8 transition of Ho3+ ion obtained the green (546 nm) light. There are two weak fluorescences in the red (657 nm) region and near infrared (753 nm) region of spectrum, which is the 5F4/5S2→5I7 and 5F5→5I8 transition of Ho3+. Therefore, the emission results showed that the incorporation of Li+ ions into the Ba2LaF7:Eu3+ lattice could induce a remarkable change of the emission intensity in red region (R = IED/IMD) with 393 nm excitation wavelength. It was indicated that the symmetry of the lattice was destroyed by Li+ in glass ceramics. The possible mechanism responsible for the enhancement of UC emission in Ho-Yb co-doped was discussed.

  8. Peculiarity of component interaction in {l_brace}Y, Dy{r_brace}-Mn-Sn ternary systems

    Energy Technology Data Exchange (ETDEWEB)

    Romaka, V.V. [Department of Materials Engineering and Applied Physics, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine); Konyk, M. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Romaka, L., E-mail: romakal@franko.lviv.ua [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Pavlyuk, V. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Jan Dlugosz University, Institute of Chemistry, Environmental Protection and Biotechnology, al. Armii Krajowej 13/15, 42200 Czestochowa (Poland); Ehrenberg, H. [Institute for Complex Materials, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden (Germany); Tkachuk, A. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine)

    2011-07-14

    Highlights: > {l_brace}Y, Dy{r_brace}-Mn-Sn ternary systems at 770 K are characterized by formation of stannides with general compositions RMn{sub 6}Sn{sub 6} and R{sub 4}Mn{sub 4}Sn{sub 7}. > The crystal structure of YMn{sub 6}Sn{sub 6} was determined by single crystal and powder diffraction methods. > Structural analysis showed that Dy{sub 4}Mn{sub 4}Sn{sub 7} compound is disordered. > Isostructural R{sub 4}Mn{sub 4}Sn{sub 7} compounds were also found with Gd, Tb, Ho, Er, Tm(confirmed), Yb, and Lu. - Abstract: The phase equilibria in the Y-Mn-Sn and Dy-Mn-Sn ternary systems were studied at 770 K by means of X-ray and metallographic analyses in the whole concentration range. Both Y-Mn-Sn and Dy-Mn-Sn systems are characterized by formation of two ternary compounds RMn{sub 6}Sn{sub 6} (MgFe{sub 6}Ge{sub 6}-type, space group P6/mmm) and R{sub 4}Mn{sub 4}Sn{sub 7} (Zr{sub 4}Co{sub 4}Ge{sub 7}-type, space group I4/mmm). The disorder in Dy{sub 4}Mn{sub 4}Sn{sub 7} compound was found by single crystal method. Compounds with the same type of structure were also found with Gd, Tb, Ho, Er, Tm (confirmed), Yb, and Lu and their lattice parameters were determined.

  9. Tunable upconversion luminescence from the phosphors of Yb{sup 3+}, Tm{sup 3+} and Ho{sup 3+} tri-doped Re{sub 2}TeO{sub 6} (Re = La, Gd, and Lu)

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jianfeng, E-mail: tangjf@swu.edu.cn; Gou, Jie; Li, Guannan; He, Hong; Li, Yuan; Li, Chunmei

    2016-07-05

    Phosphors of Re{sub 2}TeO{sub 6} (Re = La, Gd, and Lu) tri-doped with Yb{sup 3+}, Tm{sup 3+} and Ho{sup 3+} ions have been synthesized by the solid state reactions. The crystal structures have been characterized by powder XRD measurement. The SEM images have shown the average particle sizes of the phosphors can be controlled within 1 micron. Upconversion luminescences were investigated under the excitation of 976 nm laser diode. The upconversion processes were explained based on the pump dependence of upconversion emission intensity. The light color was studied in the framework of 1931 CIE diagram. The three systems have shown nice tunabilities by changing the pump intensity and rare earth ions concentration. By properly adjusting the concentration of Tm{sup 3+} ions white upconversion luminescence can be realized in all the three tri-doped systems. Results indicated that these phosphors have potential applications in the upconversion based white lighting and optoelectronic devices. - Highlights: • Upconversions of Re{sub 2}TeO{sub 6} (Re = La, Gd, and Lu) tri-doped with Yb{sup 3+}, Tm{sup 3+}, and Ho{sup 3+} were investigated. • The light colors can be well tuned in the white region via adjusting the pump power and Tm{sup 3+} concentration. • The phosphors are potentials for white lighting and optoelectronic devices.

  10. Tetranuclear hetero-metal [Co(II)2Ln(III)2] (Ln = Gd, Tb, Dy, Ho, La) complexes involving carboxylato bridges in a rare μ4-η(2):η(2) mode: synthesis, crystal structures, and magnetic properties.

    Science.gov (United States)

    Abtab, Sk Md Towsif; Majee, Mithun Chandra; Maity, Manoranjan; Titiš, Ján; Boča, Roman; Chaudhury, Muktimoy

    2014-02-01

    A new family of 3d-4f heterometal 2 × 2 complexes [Co(II)2(L)2(PhCOO)2Ln(III)2(hfac)4] (1-5) (Ln = Gd (compound 1), Tb (compound 2), Dy (compound 3), Ho (compound 4), and La (compound 5)) have been synthesized in moderate yields (48-63%) following a single-pot protocol using stoichiometric amounts (1:1 mol ratio) of [Co(II)(H2L)(PhCOO)2] (H2L = N,N'-dimethyl-N,N'-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine) as a metalloligand and [Ln(III)(hfac)3(H2O)2] (Hhfac = hexafluoroacetylacetone) as a lanthanide precursor compound. Also reported with this series is the Zn-Dy analog [Zn(II)2(L)2(PhCOO)2Dy(III)2(hfac)4] 6 to help us in understanding the magnetic properties of these compounds. The compounds 1-6 are isostructural. Both hexafluoroacetylacetonate and benzoate play crucial roles in these structures as coligands in generating a tetranuclear core of high thermodynamic stability through a self-assembly process. The metal centers are arranged alternately at the four corners of this rhombic core, and the carboxylato oxygen atoms of each benzoate moiety bind all of the four metal centers of this core in a rare μ4-η(2):η(2) bridging mode as confirmed by X-ray crystallography. The magnetic susceptibility and magnetization data confirm a paramagnetic behavior, and no remnant magnetization exists in any of these compounds at vanishing magnetic field. The metal centers are coupled in an antiferromagnetic manner in these compounds. The [Co(II)2Dy(III)2] compound exhibits a slow magnetic relaxation below 6 K, as proven by the AC susceptibility measurements; the activation energy reads U/kB = 8.8 K (τ0 = 2.0 × 10(-7) s) at BDC = 0, and U/kB = 7.8 K (τ0 = 3.9 × 10(-7) s) at BDC = 0.1 T. The [Zn(II)2Dy(III)2] compound also behaves as a single-molecule magnet with U/kB = 47.9 K and τ0 = 2.75 × 10(-7) s.

  11. Heat capacity, entropy of Ln2(MoO4)3 (Ln = La, Sm, and Gd), and the high-temperature enthalpy of Ln2(MoO4)3 (Ln = Eu, Dy, and Ho)

    Science.gov (United States)

    Lazarev, V. M.; Suponitskiy, Y. L.; Liashenko, S. E.

    2016-05-01

    The low-temperature heat capacity of Ln2(MoO4)3 (Ln = La, Sm, and Gd) is investigated by means of adiabatic calorimetry within the range of 60-300 K. The temperature dependences of the heat capacity are found and the values of the standard entropy are calculated, based on extrapolations to 0 K. Characteristic temperatures for molybdates are determined from the results of IR spectroscopic studies. The high-temperature enthalpy of Ln2(MoO4)3 (Ln = Eu, Dy, and Ho) is measured via high-temperature microcalorimetry, and the temperature dependence of heat capacity is calculated in the range of 298-1000 K. Since samarium and gadolinium molybdates are of the same structural type as terbium molybdate, we can estimate the anomaly of the heat capacity in the low-temperature region using the data for terbium molybdate and find the entropy of samarium and gadolinium molybdates.

  12. Role of Lanthanide-Ligand bonding in the magnetization relaxation of mononuclear single-ion magnets: A case study on Pyrazole and Carbene ligated LnIII(Ln=Tb, Dy, Ho, Er) complexes

    Indian Academy of Sciences (India)

    TULIKA GUPTA; GUNASEKARAN VELMURUGAN; THAYALAN RAJESHKUMAR; GOPALAN RAJARAMAN

    2016-10-01

    Ab initio CASSCF+RASSI-SO+SINGLE_ANISO and DFT based NBO and QTAIM investigations were carried out on a series of trigonal prismatic M(BcMe)₃ (M = Tb(1), Dy(2), Ho(3), Er(4), [BcMe]⁻ = dihydrobis (methylimidazolyl) borate) and M(BpMe)₃ (M = Tb(1a), Dy(2a), Ho(3a), Er(4a) [BpMe]⁻ = dihydrobis (methypyrazolyl) borate) complexes to ascertain the anisotropic variations of these two ligand field environments and the influence of Lanthanide-ligand bonding on the magnetic anisotropy. Among all the complexes studied, only 1 and 2 show large Ucal (computed energy barrier for magnetization reorientation) values of 256.4 and 268.5 cm⁻¹, respectively and this is in accordance with experiment. Experimentally only frequency dependent χ” tails are observed for complex 1a and our calculation predicts a large Ucalof 229.4 cm⁻¹ for this molecule. Besides these, none of the complexes (3, 4, 2a, 3a and 4a) computed to possess large energy barrier and this is affirmed by the experiments. These observed differences in the magnetic properties are correlated to the Ln-Ligand bonding. Our calculations transpire comparatively improved Single-Ion Magnet (SIM) behaviour for carbene analogues due to the more axially compressed trigonal prismatic ligand environment. Furthermore, our detailed Mulliken charge, spin density, NBO and Wiberg bond analysis implied stronger Ln...H–BH agostic interaction for pyrazole analogues. Further, QTAIM analysis reveals the physical nature of coordination, covalent, and fine details of the agostic interactions in all the eight complexes studied. Quite interestingly, for the first time, using the Laplacian density, we are able to quantify the prolate and oblate nature of the electron clouds in lanthanides and this is expected to have a far reaching outcome beyond the examples studied.

  13. Study of hyperfine interactions in intermetallic compounds Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In; Estudo de interacoes hiperfinas em compostos intermetalicos Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In e Ho(Ni,Pd)In

    Energy Technology Data Exchange (ETDEWEB)

    Lapolli, Andre Luis

    2006-07-01

    Systematic behavior of magnetic hyperfine field (B{sub hf}) in the intermetallic compounds Gd(Ni,Pd,Cu)In Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In was studied by Perturbed Gamma-Gamma Angular Correlation spectroscopy. The measurements of B{sub hf} were carried out at the rare earth atom and in sites using the nuclear probes {sup 140}Ce and {sup 11}'1Cd respectively. The variation of hyperfine field with temperature, in most cases, follows the Brillouin function predicted from the molecular field theory. The hyperfine field values at rare earth atom sites obtained from {sup 140}Ce probe as well as at in sites obtained from {sup 111}Cd probe for each series of compounds were extrapolated to zero Kelvin B{sub hf}(T=0) from these curves. These values were compared with the values of the literature for other compounds containing the same rare earth element and all of them show a linear relationship with the ordering temperature. This indicates that the main contribution to B{sub hf} comes from the conduction electron polarization (CEP) through Fermi contact interaction and the principal mechanism of magnetic interaction in these compounds can be described by the RKKY type interaction. The values of B{sub hf}(T=0) for each family of intermetallic compounds RNiIn and RPdIn when plotted as a function of 4f spin projection of rare earth element also shows a linear relationship. Exceptions are the results for the compounds RNiIn obtained with {sup 111}Cd probe where a small deviation from linearity is observed. The results of the measurements carried out with the {sup 111}Cd probe were also analyzed to obtain the hyperfine parameters of the quadrupole interaction as a function of temperature for RPdln and GdNiIn compounds. The results show that for the compound GdPdIn there might be some Gd-In disorder at high temperature. (author)

  14. Crystal structures of the R{sub 2}Pb{sub 3}Sn{sub 3}S{sub 12} (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gulay, L.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Avenue 13, 43009 Lutsk (Ukraine)], E-mail: gulay@univer.lutsk.ua; Ruda, I.P. [Department of General and Inorganic Chemistry, Volyn State University, Voli Avenue 13, 43009 Lutsk (Ukraine); Marchuk, O.V. [Department of Physical and Colloidal Chemistry, Volyn State University, Voli Avenue 13, 43009 Lutsk (Ukraine); Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Avenue 13, 43009 Lutsk (Ukraine)

    2008-06-12

    The crystal structures of the R{sub 2}Pb{sub 3}Sn{sub 3}S{sub 12} (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm) compounds (space group Pmc2{sub 1}, Pearson symbol oP40, a = 0.38992 (1) nm, b = 2.01175 (7) nm, c = 1.15140 (4) nm, R{sub I} 0.0785 for Ho{sub 2}Pb{sub 3}Sn{sub 3}S{sub 12}) were investigated using X-ray powder diffraction. The R{sub 1} atoms are surrounded by trigonal prisms with two additional atoms, the R{sub 2} atoms by distorted octahedra with one additional atom. The Pb{sub 1} and Pb{sub 3} atoms are surrounded by trigonal prisms with one additional atom, the Pb{sub 2} atoms by trigonal prisms with two additional atoms. Octahedral surrounding exists for Sn{sub 1} and Sn{sub 2}. The Sn{sub 3} atoms are located in trigonal bipyramids. Four or five neighbours surround the S atoms.

  15. Features of magnetic and thermal properties of R(Co{sub 1−x}Fe{sub x}){sub 2} (x≤0.16) quasibinary compounds with R=Dy, Ho, Er

    Energy Technology Data Exchange (ETDEWEB)

    Anikin, Maksim; Tarasov, Evgeniy; Kudrevatykh, Nikolay [Institute of Natural Sciences, Ural Federal University, Ekaterinburg 620002 (Russian Federation); Inishev, Aleksander [Institute of Metal Physics, Ekaterinburg 620137 (Russian Federation); Semkin, Mikhail; Volegov, Aleksey; Zinin, Aleksander [Institute of Natural Sciences, Ural Federal University, Ekaterinburg 620002 (Russian Federation)

    2016-11-15

    In this work the results of measurements of high field susceptibility, paraprocess susceptibility and thermal properties of R(Co{sub 1−x}Fe{sub x}){sub 2} intermetallic compounds (R=Dy, Ho, Er and x=(0−0.16)) are presented (heat capacity and magnetocaloric effect (MCE)). A magnetic structure of the Ho(Co{sub 0.88}Fe{sub 0.12}){sub 2} at 293 K and 78 K was studied by neutron powder diffraction. Some peculiarities of a high-field susceptibility were revealed at low temperatures and around the Curie point (T{sub C}). In temperature range lower than T{sub C} by (100–150) K, magnetic contributions to a zero-field heat capacity were found. Studying MCE in wide temperatures range, the large change of the entropy magnetic contribution (∆S) was observed which correlates with ∆T phenomenon. In particular, for the Er(Co{sub 0.84}Fe{sub 0.16}){sub 2} compound the ∆S value at low temperatures is six times higher than that at Curie point. The possible reasons of such behavior were discussed. - Highlights: • Magnetic and magnetocaloric properties of R(Co–Fe){sub 2} compounds have been studied. • Fe introduction induces the disorientation effect in Ho-ions magnetic ordering. • Emergence of magnetic contribution to a heat capacity at temperatures less T{sub C}. • The existence of a broad maximum on a temperature dependence of the MCE. • Direct MCE measurements at magnetic field of (0–17.5) kOe have been performed.

  16. Mo{sub 2}NiB{sub 2}-type (Gd, Tb, Dy){sub 2}Ni{sub 2.35}Si{sub 0.65} and La{sub 2}Ni{sub 3}-type (Dy, Ho){sub 2}Ni{sub 2.5}Si{sub 0.5} compounds: Crystal structure and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Morozkin, A.V., E-mail: morozkin@tech.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, Moscow 119992, GSP-2 (Russian Federation); Isnard, O. [CNRS, Insitut. Néel, 25 rue des Martyrs BP166, F-38042 Grenoble (France); Université Grenoble Alpes, Inst. Néel, F-38042 Grenoble (France); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600 036 (India); Malik, S.K. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59082-970 (Brazil)

    2015-05-15

    The crystal structure of new Mo{sub 2}NiB{sub 2}-type (Gd, Tb, Dy){sub 2}Ni{sub 2.35}Si{sub 0.65} (Immm, No. 71, oI10) and La{sub 2}Ni{sub 3}-type (Dy, Ho){sub 2}Ni{sub 2.5}Si{sub 0.5} (Cmce No. 64, oC20) compounds has been established using powder X-ray diffraction studies. Magnetization measurements show that the Mo{sub 2}NiB{sub 2}-type Gd{sub 2}Ni{sub 2.35}Si{sub 0.65} undergoes a ferromagnetic transition at ~66 K, whereas isostructural Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} shows an antiferromagnetic transition at ~52 K and a field-induced metamagnetic transition at low temperatures. Neutron diffraction study shows that, in zero applied field, Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} exhibits c-axis antiferromagnetic order with propagation vector K=[1/2, 0, 1/2] below its magnetic ordering temperature and Tb magnetic moment reaches a value of 8.32(5) μ{sub B} at 2 K. The La{sub 2}Ni{sub 3}-type Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} exhibits ferromagnetic like transition at ~42 K with coexisting antiferromagnetic interactions and field induced metamagnetic transition below ~17 K. The magnetocaloric effect of Gd{sub 2}Ni{sub 2.35}Si{sub 0.65}, Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} and Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} is calculated in terms of isothermal magnetic entropy change and it reaches a maximum value of −14.3 J/kg K, −5.3 J/kg K and −10.3 J/kg K for a field change of 50 kOe near 66 K, 52 K and 42 K, respectively. Low temperature magnetic ordering with enhanced anisotropic effects in Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} and Dy{sub 2}Ni{sub 2.35}Si{sub 0.65} is accompanied by a positive magnetocaloric effect with isothermal magnetic entropy changes of +12.8 J/kg K and ~+9.9 J/kg K, respectively at 7 K for a field change of 50 kOe. - Graphical abstract: The (Gd, Tb, Dy){sub 2}Ni{sub 2.35}Si{sub 0.65} supplement the series of Mo{sub 2}NiB{sub 2}-type rare earth compounds, whereas the (Dy, Ho){sub 2}Ni{sub 2.5}Si{sub 0.5} supplement the series of La{sub 2}Ni{sub 3}-type rare

  17. Yb3+-Ho3+-F-共掺杂TiO2纳米晶的上转换发光性能及其在染料敏化太阳能电池中的应用%Up-conversion Luminescent Properties and Application in Dye-sensitized Solar Cells of Ho3+-Yb3+-F Co-doped TiO2 Nanocrystals

    Institute of Scientific and Technical Information of China (English)

    宋丽丽; 李忠源; 肖志明; 刘俊; 招瑜; 魏爱香

    2016-01-01

    采用溶胶-水热法制备了Yb3-Ho3+-F-共掺杂的TiO2(简写为UC-F-TiO2)纳米粉末.通过XRD,TEM,拉曼光谱,XPS和发光光谱,研究了yb3掺杂浓度对UC-F-TiO2纳米粉末的结构、形貌和上转换发光性能的影响规律.结果表明:UC-F-TiO2纳米粉末颗粒的大小约20 nm,由金红石和锐钛矿两种结构混合组成,且随着yb3+掺杂浓度的增加,金红石结构的TiO2所占比例增加;在980 nm激光激发下,UC-F-TiO2发射出中心在543 nm、647 nm和751 nm处的三个发光带.研究了基于UC-F-TiO2和纯TiO2纳米多孔薄膜光阳极的染料敏化电池的光伏性能.结果表明:与纯TiO2制备的电池相比,将UC-F-TiO2应用于染料敏化电池,电池的光电转换效率提高了29.7%.

  18. Solid-state synthesis and lanthanide photoluminescence of doped yttrium molybdo-antimonites, Y{sub 2−n}A{sub n}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er; n=0.02–2) solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Mohitkar, Shrikant A.; Vidyasagar, K., E-mail: kvsagar@iitm.ac.in

    2015-05-15

    Abstract:: Y{sub 2−n}A{sub n}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er; n=0.02–2) solid solutions were synthesized by a solid-state method and studied for their lanthanide photoluminescence. They show concentration dependent lanthanide photoluminescence and existence of concentration quenching phenomenon. The emission intensity and the fluorescence-lifetime are found to be highest for an optimum concentration of a given lanthanide ion in the solid solution series studied. The neat photoluminescence of A{sub 2}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er) compounds involves partial concentration quenching. - Highlights: • Isostructural Y{sub 2−n}A{sub n}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er; n=0.02–2) solid solutions have been synthesized. • Lanthanide photoluminescence of Y{sub 2−n}A{sub n}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er; n=0.02–2) solid solutions has been studied. • Optimum concentration of each photoluminescent dopant for Y{sub 2−n}A{sub n}Mo{sub 4}Sb{sub 2}O{sub 18} (A=Pr, Sm, Eu, Tb, Dy, Ho, and Er; n=0.02 –2) solid solutions has been determined. • Red photoemission of Eu{sup 3+} in Y{sub 1.5}Eu{sub 0.5}Mo{sub 4}Sb{sub 2}O{sub 18} is visible to the naked eye. • Green photoemission of Tb{sup 3+} in Y{sub 1.7}Tb{sub 0.3}Mo{sub 4}Sb{sub 2}O{sub 18} is visible to the naked eye.

  19. Canted magnetic ground state of quarter-doped manganites R 0.75Ca0.25MnO3 (R  =  Y, Tb, Dy, Ho, and Er)

    Science.gov (United States)

    Sinclair, R.; Cao, H. B.; Garlea, V. O.; Lee, M.; Choi, E. S.; Dun, Z. L.; Dong, S.; Dagotto, E.; Zhou, H. D.

    2017-02-01

    Polycrystalline samples of the quarter-doped manganites R 0.75Ca0.25MnO3 (R  =  Y, Tb, Dy, Ho, and Er) were studied by x-ray diffraction and AC/DC susceptibility measurements. All five samples are orthorhombic and exhibit similar magnetic properties: enhanced ferromagnetism below T 1 (∼80 K) and a spin glass (SG) state below T SG (∼30 K). With increasing R 3+ ionic size, both T 1 and T SG generally increase. The single crystal neutron diffraction results on Tb0.75Ca0.25MnO3 revealed that the SG state is mainly composed of a short-range ordered version of a novel canted (i.e. noncollinear) antiferromagnetic spin state. Furthermore, calculations based on the double exchange model for quarter-doped manganites reveal that this new magnetic phase provides a transition state between the ferromagnetic state and the theoretically predicted spin-orthogonal stripe phase.

  20. Correlation between upconversion photoluminescence and dielectric response in Ba-substituted (Sr{sub 1−x}Ba{sub x}){sub 4}(La{sub 0.85}Ho{sub 0.025}Yb{sub 0.125}){sub 2}Ti{sub 4}Nb{sub 6}O{sub 30}

    Energy Technology Data Exchange (ETDEWEB)

    Wei, T., E-mail: weitong.nju@gmail.com [College of Science, Civil Aviation University of China, Tianjin 300300 (China); Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Wang, X. D. [College of Science, Civil Aviation University of China, Tianjin 300300 (China); Zhao, C. Z. [School of Electronics and Information Engineering, Tianjin Polytechnic University, Tianjin 300160 (China); Liu, M. F.; Liu, J. M., E-mail: liujm@nju.edu.cn [Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China)

    2014-06-30

    The filled tetragonal tungsten bronze (Sr{sub 1−x}Ba{sub x}){sub 4}(La{sub 0.85}Ho{sub 0.025}Yb{sub 0.125}){sub 2}Ti{sub 4}Nb{sub 6}O{sub 30} (SBLTNx: Ho-Yb) ceramics with different Ba substitution levels (x) are prepared. The upconversion photoluminescence (UC-PL) and dielectric permittivity are investigated. The substitution of Sr{sup 2+} ions at the A{sub 2}-sites by larger Ba{sup 2+} ions results in substantial variation of the UC-PL intensity as a function of substitution level x. Furthermore, the dielectric response to the substitution of Sr{sup 2+} by Ba{sup 2+} suggests a close correlation between the UC-PL intensity and dielectric permittivity. The origin for this correlation is discussed based on the random stress field (RSF) model.

  1. Large electric polarization in high pressure synthesized orthorhombic manganites RMnO3 (R=Ho,Tm,Yb and Lu) by using the double-wave PE loop measurements

    Science.gov (United States)

    Chai, Y. S.; Oh, Y. S.; Manivannan, N.; Yang, Y. S.; Kim, Kee Hoon; Feng, S. M.; Wang, L. J.; Jin, C. Q.

    2009-03-01

    The magnitude of electric polarization via the conventional pyroelectric current and/or PE loop measurements often is ambiguous due to resistive components of the sample. To avoid this, a new technique called the double-wave method has been recently developed [1], in which only hysteretic PE components can be measured. Using this technique, we have measured the ferroelectric polarization of the orthorhombic RMnO3 (R=Ho, Tm, Yb, and Lu) synthesized under high pressure. Large remnant polarization Pr up to 920 μC/m^2 is observed at 10 K for LuMnO3. Furthermore, the Pr vs. temperature data from the PE loop has shown consistency with that measured through the pyroelectric current measurements, supporting a theoretical prediction of large polarization in the E-type spin structure in this system [2]. We also discuss the influence of thermal histories on the ferroelectric domain dynamics and possible internal bias field effects originating from oxygen vacancies in RMnO3. [1] M. Fukunaga, et al. J. Phys. Soc. Jpn. 77, 064706 (2008). [2] I. A. Sergienko, et al. Phys. Rev. Lett., 97, 227204 (2006)

  2. Synthesis and study of spectroscopic properties of CdF{sub 2} crystals codoped with luminescent rare earth ions (Ho{sup 3+}/Yb{sup 3+})

    Energy Technology Data Exchange (ETDEWEB)

    Fartas, R. [Laboratory of Laser Physics, Optical Spectroscopy and Optoelectronics (LAPLASO), Badji Mokhtar Annaba University, POB 12, 23000 Annaba (Algeria); Diaf, M., E-mail: diafma@yahoo.fr [Laboratory of Laser Physics, Optical Spectroscopy and Optoelectronics (LAPLASO), Badji Mokhtar Annaba University, POB 12, 23000 Annaba (Algeria); Boubekri, H. [Laboratory of Laser Physics, Optical Spectroscopy and Optoelectronics (LAPLASO), Badji Mokhtar Annaba University, POB 12, 23000 Annaba (Algeria); Guerbous, L. [Laser Department, Nuclear Technique Division, Nuclear Research Center of Algiers, 02 Bd Frantz Fanon, 16000 Algiers (Algeria); Jouart, J.P. [ECATHERM/GRESPI, Reims Champagne-Ardenne University (France)

    2014-09-01

    Highlights: • Holmium doped CdF{sub 2} single crystals grown by Bridgman technique. • Absorption, excitation, emission spectra and fluorescence decay recorded at room temperature. • Spectroscopic properties investigated by use of the Judd–Ofelt theory. • Radiative lifetimes and branching ratios of the main emitting levels are calculated. • Laser parameters such as emission cross-section, radiative quantum efficiency and optical gain are then deduced. - Abstract: In this paper, we report the optical analysis of Ho{sup 3+} ions doped CdF{sub 2} single crystals. The pulled crystals were prepared by use of the Bridgman technique from a vacuum furnace in fluoride atmosphere after purification of the starting materials. Absorption, excitation, emission and fluorescence decay spectra were recorded at room temperature. The Judd–Ofelt (JO) analysis was applied to obtain the three phenomenological intensity parameters (Ω{sub t}, t = 2, 4, 6) and the transition strengths. The JO intensity parameters Ω{sub 2}, Ω{sub 4} and Ω{sub 6} for 4f–4f transitions of Ho{sup 3+} ions were computed from the optical absorption spectra using UV, visible and near infrared transitions. These parameters were then used to calculate the radiative transition probabilities (A{sub JJ′}), branching ratios (β{sub JJ′}) and radiative lifetimes (τ{sub rad}) of the main laser emitting levels of Ho{sup 3+} ions. The obtained spectroscopic properties are compared to those of Ho{sup 3+} transitions in other fluoride and oxide hosts. The excitation spectrum in the UV–Visible spectral range is very close to the absorption spectrum indicating that all observed absorption levels can excite the holmium green emission corresponding to {sup 5}F{sub 4}({sup 5}S{sub 2}) → {sup 5}I{sub 8} transition. The emission spectrum is mainly dominated by the green emission alongside the blue and red emissions. For the main transitions, there is a good agreement between the emission spectrum and

  3. BaFCl晶体中三价稀土离子Sm3+、Eu3+、Gd3+、Ho3+、Er3+和Yb3+的电荷转移激发%Charge Transfer Excitation of Rare Earth Ions (Sm3+, Eu3+, Gtl2+, Ho3+, Er3+ and Yb3+) Emission in BaFCl Crystal

    Institute of Scientific and Technical Information of China (English)

    苏勉曾; 孙小平

    1986-01-01

    @@ 1962年Jфrgensen[1]提出了精细电子自旋配对能理论(RESPET),计算由配体提供一个电子、将具有4fq基态的Ln3+还原为具有4fq+1的Ln2+这个电荷转移过程(CT)的能量变化.计算公式为Jфrgensen指出了公式中各参数的意义,并给出了各稀土离子的N(S)、M(L)和P(S,L,J)等系数的值[2,3].我们合成了Sm3+、Eu3+、Gd3+、Ho3+、Er3+和yb3+离子激活的六种BaFCl晶体,测定了它们的激发光谱(图1).由光谱数据确定了它们的电荷转移带(CTS)的波长和波数(另一报告已证明Eu 3+的CTS位于242nm[4]),利用公式(1)对以上各三价希土离子的电荷转移带的能量进行了计算.

  4. Spectroscopic characterization and temporal dynamics of energy transfer process between Tm{sup 3+} -Ho{sup 3+} and Yb{sup 3+} -Tm{sup 3+} ions in LiYF{sub 4} and LiLuF{sub 4} crystals; Caracterizacao espectroscopica e dinamica temporal dos processos de transferencia de energia entre os ions Tm{sup 3+} -Ho{sup 3+} e Yb{sup 3+} -Tm{sup 3+} em cristais de LiYF{sub 4} and LiLuF{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Tarelho, Luiz Vicente Gomes

    2001-07-01

    In this work, we perform spectroscopic studies to characterize the energy transfer processes occurring in rare-earth doped lithium fluoride systems, aiming the optimization of the population inversion of these media. Yb{sup 3+} ion was used in order to probe the electron-phonon coupling in LiYF{sub 4}, LiGdF{sub 4} and LiLuF{sub 4} matrices. In these systems it was obtained the average phononenergy, the vibronic transition probability and Huang-Rhys coupling constant. These parameters are dependent on the crystal host and the LiLuF{sub 4} system presents excluded correlation effects, an electronic repulsion that weakens the vibronic coupling. The Tm:Ho:LiYF{sub 4} system was studied under diode laser pumping at 796 nm, aiming the 2 {mu}m emission optimization. The ideal conditions of concentration and laser power were determined favouring the latter emission. Upconversion processes of two photons were identified besides the energy transfer among ions. The dynamic processes of luminescence of donors and acceptors allowed one to classify the energy transfer process as an energy transfer process assisted by fast diffusion among donors. The spectroscopic study of the Yb:Tm:LiYF{sub 4} allowed the determination of efficient non resonant transfer mechanisms between ({sup 2}F{sub 5/2}) Ytterbium level and ({sup 3}H{sub 5}) Thulium level, assisted by two phonon with hopping migration among donors ( Foerster-Burshtein model). The repopulation process of the Yb donor level is due to a cooperative sensitization between Yb-Tm pairs followed by an energy transfer process. (author)

  5. Color tunability in green, red and infra-red upconversion emission in Tm{sup 3+}/Yb{sup 3+}/Ho{sup 3+} co-doped CeO{sub 2} with potential application for improvement of efficiency in solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Luiz G.A.; Rocha, Leonardo A.; Buarque, Juliana M.M. [Laboratório de Materiais Inorgânicos Fotoluminescentes e Polímeros Biodegradáveis (LAFOP), Grupo de Pesquisa em Química de Materiais – (GPQM), Departamento de Ciências Naturais, Universidade Federal de São João Del Rei, Campus Dom Bosco, Praça Dom Helvécio, 74, 36301-160 São João Del Rei, MG (Brazil); Gonçalves, Rogéria Rocha [Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, USP, Av. Bandeirantes, 3900, 14040-901 Ribeirão Preto, SP (Brazil); Nascimento Jr, Clébio S. [Laboratório de Química Teórica e Computacional – (LQTC), Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, Campus Dom Bosco, Praça Dom Helvécio, 74, 36301-160 São João del-Rei, MG (Brazil); and others

    2015-03-15

    The preparation of Tm{sup 3+}/Yb{sup 3+}/Ho{sup 3+} co-doped CeO{sub 2} prepared by the precipitation method using ammonium hydroxide as a precursor is presented. By X-ray diffraction the materials show the phase-type of fluorite structure and the crystallite sizes were calculated by the Scherrer's equation. No other phase was observed evincing that the rare earth ions were inserted into the fluorite phase as substitutional or interstitial dopants. The microstrain calculated by the Williamson–Hall method do not show significant changes in their values, indicating that the inclusion of rare earths does not causes structural changes in the CeO{sub 2} used as a host matrix. All material showed intense upconversion emission at red and green region under excitation with diode laser at 980 nm. The color of emission changes from green to red with increasing excitation power pump. The materials showed suitable photoluminescent properties for applications as a laser source, solar cells, and great emitter at 800 nm. - Highlights: • Tm{sup 3+}/Yb{sup 3+}/Ho{sup 3+} co-doped CeO{sub 2} prepared by the simple way. • Intense upconversion emission regions and the tunability of emission color by the laser power pump. • The materials showed suitable photoluminescent properties for different applications.

  6. Double symmetry breaking in TmFe{sub 4}Ge{sub 2} compared to RFe{sub 4}Ge{sub 2} (R=Y, Lu, Er, Ho, Dy) magnetic behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Schobinger-Papamantellos, P., E-mail: Schobinger@mat.ethz.ch [Laboratory of Crystallography, ETH-Zürich, 8093 Zürich (Switzerland); Buschow, K.H.J. [Van der Waals-Zeeman Institute, University of Amsterdam, NL-1018 XE (Netherlands); Rodríguez-Carvajal, J. [Institut Laue-Langevin, 156X, 38042 Grenoble Cédex (France)

    2014-04-15

    TmFe4Ge{sub 2} undergoes a double magneto-elastic first order transition at T{sub N},T{sub c} where the high temperature (HT) tetragonal phase disproportionate into two distinct orthorhombic low temperature (LT) phases with commensurate and incommensurate magnetic wave vectors respectively: P4{sub 2}/mnm(HT)T{sub N},T{sub c}→Cmmmq{sub 1}=(0,1/2 ,0)+Pnnm(q{sub 2}=(0,q{sub y},0),q{sub y}≈2/11(LT) Neutron diffraction shows the relative portions of the LT Cmmm and Pnnm competing phases change linearly with T. The amount of the majority HT phase Pnnm (54% at 30 K) decreases linearly to 30% down to 10 K in favour of the Cmmm phase that dominates the range 26–1.5 K. The Tm moments point along the c-axis in both phases while the Fe moments have canted arrangements. The μ{sub Tm}=3.54(3) μ{sub B}/atom at 1.5 K is strongly reduced below the Tm{sup 3+} free ion value g{sub J}J=7 μ{sub B} for the q{sub 1} phase. The q{sub 2} phase corresponds to a 3D canted sinusoidal arrangement. The results are summarised on a phase diagram and compared to the findings in RFe{sub 4}Ge{sub 2} (R=Y, Lu, Er, Ho, Dy) that are reviewed. The multitude of transition paths occurring in those systems arise from the competing magnetoelastic mechanisms involving the R-crystal field anisotropy, the exchange interactions R–R, R–Fe, Fe–Fe of the two sublattices and their coupling to the lattice strain. The geometrical frustration emerging from the compact tetrahedral Fe arrangement with antiferromagnetic interactions leads to 2D and 3D canted, incommensurate and non-magnetic states. The Cmmm transition is triggered by dominating R–R and R–Fe interactions becoming stronger at LT while the Pnnm phase is promoted by Fe–Fe and R–Fe interactions that prevail at HT. Included is also the magnetic structure of the ferromagnetic impurity phase Fe{sub 3}Ge. - Highlights: • Magnetic phase diagram of tetragonal TmFe{sub 4}Ge{sub 2} compound studied by neutron diffraction. • Unusual first

  7. Výchova ke zdraví v učebnicích 1. stupně ZŠ: výsledky analýzy didaktického aparátu učebnic prvouky/přírodovědy/Health education in primary school textbooks – results of a content analysis

    Directory of Open Access Journals (Sweden)

    Markéta Hrozová

    2015-02-01

    Full Text Available Cílem empirické studie je prezentace výsledků obsahové analýzy didaktického aparátu učebnic a cvičebnic školního vzdělávacího předmětu prvouka/přírodověda určených pro žáky 1. stupně základních škol z hlediska jejich zaměření na výchovu ke zdraví. V první části studie prezentujeme teoretický základ našeho výzkumu, který spočíval ve vymezení analytických kategorií vyplývajících z holistického pojetí zdraví. V druhé části představujeme cíle a metody výzkumu, výzkumný vzorek sestávající z pěti současných ucelených učebnicových řad učebnic prvouky/ přírodovědy (38 učebnic/cvičebnic; 3136 zkoumaných jednotek, tedy otázek, námětů a úkolů zařazených do učebnic platných pro 1. stupeň základního vzdělávání. Třetí část je věnována výsledkům analýzy, která poukázala na významné rozdíly v prezentaci učiva v oblasti výchova ke zdraví. Z výsledků vyplývá nereflektování holistického pojetí zdraví v jeho plném rozsahu, majoritní zastoupení biologického kontextu zdraví ve zkoumaných učebnicích. Holistické pojetí zdraví nejvíce reflektují učebnice druhých ročníků. Dále poukazujeme na významné rozdíly ve strukturaci učiva v rámci jednotlivých učebnicových řad (absence tematiky zdraví ve většině zkoumaných učebnic 4. ročníků a nestabilitu v distribuci tematických celků zkoumaného vzorku učebnic. V závěru studie (čtvrtá a pátá část jsou diskutovány výsledky, možnosti a limity studie a představujeme eventuality navazujícího výzkumného šetření.

  8. Yb-doped Gd2O2CO3: Structure, microstructure, thermal and magnetic behaviour

    Science.gov (United States)

    Artini, Cristina; Locardi, Federico; Pani, Marcella; Nelli, Ilaria; Caglieris, Federico; Masini, Roberto; Plaisier, Jasper Rikkert; Costa, Giorgio Andrea

    2017-04-01

    Structural and microstructural features, as well as thermal and magnetic properties of Yb-doped Gd2O2CO3, were investigated with the aim to clarify the location and the oxidation state of Yb within the structure, and its role in driving the extent of the (Gd1-xYbx)2O2CO3 solid solution. Yb is found in the 3+ oxidation state and it enters the structure only at the rare earth atomic site; the solubility limit results to be located in the close vicinity of x=0.25, and thermal analyses reveal a linear decrease of the decomposition temperature with increasing the Yb amount, in agreement with literature data. The structural analysis allows to exclude long-range clusterization of Yb and Gd, since both rare earths randomly distribute over the 4f atomic position, but relying on the results of the microstructural analysis, the presence of compositional inhomogenities at the local scale cannot be excluded. Not all the structural forms are documented for the pure rare earth dioxycarbonates [1]; in particular, while form I exists for each lanthanide ion, form II is stable only for the largest ones (from La to Dy); moreover, even if II-Ho2O2CO3 (rHo3+ CN8=1.015 Å [6]) is not reported to be stable, the existence of II-Y2O2CO3 (rY3+ CN8=1.019 Å [6]) has been claimed [7]. Based on the described evidence, the stability of hexagonal Yb-doped Gd2O2CO3 is not expected along the whole compositional range. As a general remark, not all the rare earth mixed dioxycarbonates exist: (Ce, Gd)2O2CO3, for instance, could not be obtained at any composition [8]; moreover, all the structural forms can be observed only in some mixed systems, such as for example (Gd, Nd)2O2CO3, by varying temperature and tuning the composition [9]. Rare earth dioxycarbonates are studied mainly for their CO2 sensing properties [10,11], and for their emission when properly doped with a luminescent lanthanide ion [12-17]. Recently, a study of this research group [18] revealed in Gd2O2CO3:4% Yb a phenomenon of

  9. Isolation of {sup 163}Ho from dysprosium target material by HPLC for neutrino mass measurements

    Energy Technology Data Exchange (ETDEWEB)

    Mocko, Veronika; Taylor, Wayne A.; Nortier, Francois M.; Engle, Jonathan W.; Pollington, Anthony D.; Kunde, Gerd J.; Rabin, Michael W.; Birnbaum, Eva R. [Los Alamos National Laboratory, Los Alamos, NM (United States). Chemistry Div.; Barnhart, Todd E.; Nickles, Robert J. [Univ. Wisconsinn, Madison, WI (United States). Dept. of Medical Physics

    2015-07-01

    The rare earth isotope {sup 163}Ho is of interest for neutrino mass measurements. This report describes the isolation of {sup 163}Ho from a proton-irradiated dysprosium target and its purification. A Dy metal target was irradiated with 16 MeV protons for 10 h. After target dissolution, {sup 163}Ho was separated from the bulk Dy via cation-exchange high performance liquid chromatography using 70 mmol dm{sup -3} α-hydroxyisobutyric acid as the mobile phase. Subsequent purification of the collected Ho fraction was performed to remove the α-hydroxyisobutyrate chelating agent and to concentrate the Ho in a low ionic strength aqueous matrix. The final solution was characterized by MC-ICP-MS to determine the {sup 163}Ho/{sup 165}Ho ratio, {sup 163}Ho and the residual Dy content. The HPLC purification process resulted in a decontamination factor 1.4 x 10{sup 5} for Dy. The isolated Ho fraction contained 24.8 ± 1.3 ng of {sup 163}Ho corresponding to holmium recovery of 72 ± 3%.

  10. Hetero-metallic {3d-4f-5d} complexes: preparation and magnetic behavior of trinuclear [(L(Me2)Ni-Ln){W(CN)(8)}] compounds (Ln = Gd, Tb, Dy, Ho, Er, Y; L(Me2) = Schiff base) and variable SMM characteristics for the Tb derivative.

    Science.gov (United States)

    Sutter, Jean-Pascal; Dhers, Sébastien; Rajamani, Raghunathan; Ramasesha, S; Costes, Jean-Pierre; Duhayon, Carine; Vendier, Laure

    2009-07-06

    Assembling bimetallic {Ni-Ln}(3+) units and {W(CN)(8)}(3-) is shown to be an efficient route toward heteronuclear {3d-4f-5d} compounds. The reaction of either the binuclear [{L(Me2)Ni(H(2)O)(2)}{Ln(NO(3))(3)}] complexes or their mononuclear components [L(Me2)Ni] and Ln(NO(3))(3) with (HNBu(3))(3){W(CN)(8)} in dmf followed by diffusion of tetrahydrofuran yielded the trinuclear [{L(Me2)NiLn}{W(CN)(8)}] compounds 1 (Ln = Y), 2a,b (Gd), 3a,b (Tb), 4 (Dy), 5 (Ho), and 6 (Er) as crystalline materials. All of the derivatives possess the trinuclear core resulting from the linkage of the {W(CN)(8)} to the Ni center of the {Ni-Ln} unit. Differences are found in the solvent molecules acting as ligands and/or in the lattice depending on the crystallization conditions. For all the compounds ferromagnetic {Ni-W} and {Ni-Ln} (Ln = Gd, Tb, Dy, and Er} interactions are operative resulting in high spin ground states. Parameterization of the magnetic behaviors for the Y and Gd derivatives confirmed the strong cyano-mediated {Ni-W} interaction (J(NiW) = 27.1 and 28.5 cm(-1)) compared to the {Ni-Gd} interaction (J(NiGd) = 2.17 cm(-1)). The characteristic features for slow relaxation of the magnetization are observed for two Tb derivatives, but these are modulated by the crystal phase. Analysis of the frequency dependence of the alternating current susceptibility data yielded U(eff)/k(B) = 15.3 K and tau(0) = 4.5 x 10(-7) s for one derivative whereas no maxima of chi(M)'' appear above 2 K for the second one.

  11. Crystal growth, structure, and physical properties of Ln(Cu,Al)12 (Ln = Y, Ce, Pr, Sm, and Yb) and Ln(Cu, Ga)12 (Ln = Y, Gd-Er, and Yb).

    Science.gov (United States)

    Drake, Brenton L; Capan, C; Cho, Jung Young; Nambu, Y; Kuga, K; Xiong, Y M; Karki, A B; Nakatsuji, S; Adams, P W; Young, D P; Chan, Julia Y

    2010-02-17

    Single crystals of Ln(Cu,Al)12 and Ln(Cu,Ga)12 compounds (Ln = Y, Ce-Nd, Sm, Gd-Ho, and Yb for Al and Ln = Y, Gd-Er, Yb for Ga) have been grown by flux-growth methods and characterized by means of single-crystal x-ray diffraction, complemented with microprobe analysis, magnetic susceptibility, resistivity and heat capacity measurements. Ln(Cu,Ga)12 and Ln(Cu,Al)12 of the ThMn12 structure type crystallize in the tetragonal I4/mmm space group with lattice parameters a approximately 8.59 Å and c approximately 5.15 Å and a approximately 8.75 Å and c approximately 5.13 Å for Ga and Al containing compounds, respectively. For aluminium containing compounds, magnetic susceptibility data show Curie-Weiss paramagnetism in the Ce and Pr analogues down to 50 K with no magnetic ordering down to 3 K, whereas the Yb analogue shows a temperature-independent Pauli paramagnetism. Sm(Cu,Al)12 orders antiferromagnetically at T(N)approximately 5 K and interestingly exhibits Curie-Weiss behaviour down to 10 K with no Van Vleck contribution to the susceptibility. Specific heat data show that Ce(Cu,Al)12 is a heavy fermion antiferromagnet with T(N) approximately 2 K and with an electronic specific heat coefficient γ0 as large as 390 mJ K2 mol(-1). In addition, this is the first report of Pr(Cu,Al)12 and Sm(Cu,Al)12 showing an enhanced mass (approximately 80 and 120 mJ K(2) mol(-1)). For Ga containing analogues, magnetic susceptibility data also show the expected Curie-Weiss behaviour from Gd to Er, with the Yb analogue being once again a Pauli paramagnet. The antiferromagnetic transition temperatures range over 12.5, 13.5, 6.7, and 3.4 K for Gd, Tb, Dy, and Er. Metallic behaviour is observed down to 3 K for all Ga and Al analogues. A large positive magnetoresistance up to 150% at 9 T is also observed for Dy(Cu,Ga)12. The structure, magnetic, and transport properties of these compounds will be discussed.

  12. On the structures of the rare-earth metal germanides from the series REAl1-xGe3 (RE = Nd, Sm, Gd, Tb, Dy, Ho; 0.6 < x < 0.9). A tale of vacancies at the Al sites and the concomitant structural modulations.

    Science.gov (United States)

    Zhang, Jiliang; Liu, Yanyan; Shek, Chan Hung; Wang, Yingmin; Bobev, Svilen

    2017-07-18

    A series of ternary rare-earth metal aluminum germanides with the general formula REAl1-xGe3 (RE = Nd, Sm, Gd, Tb, Dy, and Ho; 0.6 < x < 0.9) have been synthesized by direct fusion of the corresponding elements. Their structures have been characterized by single-crystal X-ray diffraction and selected area electron diffraction methods. The average structure for all members is a representative of the orthorhombic SmNiGe3-type structure (Pearson symbol oS20, space group Cmmm), where the Al atoms occupy the Ni site, and the deep off-stoichiometry is due to statistical vacancies at this position. Considering long-range ordering of the vacancies, a monoclinic and a different orthorhombic structure, which represent idealized ordered variants, are possible, and the structural evolution depending on the nature of the rare-earth metals and the amount of vacancies at the aluminum site are discussed. Commensurate and incommensurate structural modulations based on these parent structures are also observed by electron diffraction, attesting to the great structural complexity in these systems. Magnetic susceptibility measurements are presented and discussed, along with the results from electronic band-structure calculations.

  13. Sulfate Exchange of the Nitrate-Type Layered Hydroxide Nanosheets of Ln2(OH)5NO3· nH2O for Better Dispersed and Multi-color Luminescent Ln2O3 Nanophosphors (Ln = Y0.98RE0.02, RE = Pr, Sm, Eu, Tb, Dy, Ho, Er, and Tm)

    Science.gov (United States)

    Wu, Xiaoli; Liu, Weigang; Li, Ji-Guang; Zhu, Qi; Li, Xiaodong; Sun, Xudong

    2016-07-01

    Through restricting thickness growth by performing coprecipitation at the freezing temperature of ~4 °C, solid-solution nanosheets (up to 5-nm thick) of the Ln2(OH)5NO3· nH2O layered hydroxide (Ln = Y0.98RE0.02; RE = Pr, Sm, Eu, Tb, Dy, Ho, Er, and Tm, respectively) were directly synthesized without performing conventional exfoliation. In situ exchange of the interlayer NO3 - with SO4 2- produced a sulfate derivative [Ln2(OH)5(SO4)0.5· nH2O] of the same layered structure and two-dimensional crystallite morphology but substantially contracted d 002 basal spacing (from ~0.886 to 0.841 nm). The sulfate derivative was systematically compared against its nitrate parent in terms of crystal structure and phase/morphology evolution upon heating. It is shown that the interlayer SO4 2-, owing to its bonding with the hydroxide main layer, significantly raises the decomposition temperature from ~600 to 1000 °C to yield remarkably better dispersed oxide nanopowders via a monoclinic Ln2O2SO4 intermediate. The resultant (Y0.98RE0.02)2O3 nanophosphors were studied for their photoluminescence to show that the emission color, depending on RE3+, spans a wide range in the Commission Internationale de l'Eclairage (CIE) chromaticity diagram, from blue to deep red via green, yellow, orange, and orange red.

  14. Physical Properties of RE2 Ti3 Si4 (RE=Gd,Tb,Dy,Ho and Er)from First-principles Calculations%RE2 Ti3Si4(RE=Gd,Tb,Dy,Ho和Er)物理性质的第一性原理研究

    Institute of Scientific and Technical Information of China (English)

    陶小马; 陈晨; 郭子凤; 王戎丞; 陈红梅; 欧阳义芳

    2014-01-01

    【目的】对 RE2 Ti3 Si4(RE=Gd,Tb,Dy,Ho和 Er)的物理性能进行研究。【方法】利用基于密度泛函的第一性原理方法对 RE2 Ti3 Si4(RE=Gd,Tb,Dy,Ho 和 Er)的结构性质、电子结构、力学以及热力学性质进行计算。对RE2 Ti3 Si4单晶的弹性常数,多晶的体积模量、剪切模量和杨氏模量都进行了计算。利用准谐的德拜模型计算获得了体积模量、比热熔和热膨胀系数随着温度和压强的变化,并进行了相关的讨论。【结果】RE2 Ti3 Si4的晶格常数计算值和实验值吻合较好。【结论】形成焓的计算值随着稀土元素原子序数的增加而呈现微小的下降趋势,这表明化合物的稳定性随着原子序数的增加而加强。电子态密度显示在费米能级之下,Ti-3d和 RE-5d的态密度有着很强的杂化现象。%Objective]Physical properties of the RE2 Ti3 Si4 (RE=Gd,Tb,Dy,Ho and Er)are studied.[Methods]We present the structural,electronic structure,mechanical and thermody-namic properties of the RE2 Ti3 Si4 (RE=Gd,Tb,Dy,Ho and Er)by using first-principles calcu-lations based on the density functional theory (DFT).[Results]The calculated lattice constants of RE2 Ti3 Si4 are all in good agreement with experimental data.The single crystal elastic con-stants of RE2 Ti3 Si4 have been calculated,and the bulk,shear and Young's modulus are all been estimated in this work.Finally,using a quasi-harmonic Debye model,the bulk modulus,heat ca-pacity,and coefficient of thermal expansion have also been obtained and discussed.[Conclusion]The calculated formation enthalpies of the RE2 Ti3 Si4 show tiny decline trend with the increas-ing atomic number,which indicates that phase stability of RE2 Ti3 Si4 enhance slightly with in-creasing atomic number.The electronic densities of states indicate that Ti-3d and RE-5d peaks show strong hybridization below the Fermi level.

  15. Etude structurale des sulfotellurures de terres rares ( LS) 2Te 1 + x ( L = Tb, Dy, Ho, Er, Tm et Y). II. Surstructure des phases ordonnées. Macles d'ordre

    Science.gov (United States)

    Ghémard, Geneviève; Etienne, Jean; Schiffmacher, Gérard; Flahaut, Jean

    1982-11-01

    The ( LS) 2Te 1 + x compounds have an orthorhombic subcell, with a layered structure and vacant Te sites, and a monoclinic superstructure ( a = b = 6.658, c = 13.657 Å, γ = 102°43' for (HoS) 2Te 1.34). The order-disorder transition occurs at about 450°C. In the superstructure Te planes between ( L4S) tetrahedra layers are ordered with {B2}/{m} symmetry; however, some sites remain partially vacant. The S atoms conserve mmm symmetry, but the metallic atoms are slightly displaced from their substructure position ( R = 0.037). Ordering occurs so that each Te plane can be oriented in two different ways. Therefore, there are two kinds of domains, with respect to a twinning rule. These domains are observed by direct-imaging high-resolution electronic microscopy and are about 100 Å wide.

  16. Enhanced near-infrared to visible upconversion nanoparticles of Ho³⁺-Yb³⁺-F⁻ tri-doped TiO₂ and its application in dye-sensitized solar cells with 37% improvement in power conversion efficiency.

    Science.gov (United States)

    Yu, Jia; Yang, Yulin; Fan, Ruiqing; Liu, Danqing; Wei, Liguo; Chen, Shuo; Li, Liang; Yang, Bin; Cao, Wenwu

    2014-08-04

    New near-infrared (NIR)-to-green upconversion nanoparticles of Ho(3+)-Yb(3+)-F(-) tridoped TiO2 (UC-F-TiO2) were designed and fabricated via the hydrosol-hydrothermal method. Under 980 nm NIR excitation, UC-F-TiO2 emit strong green upconversion fluorescence with three emission bands at 543, 644, and 751 nm and convert the NIR light in situ to the dye-sensitive visible light that could effectively reduce the distance between upconversion materials and sensitizers; thus, they minimize the loss of the converted light. Our results show that this UC-F-TiO2 offers excellent opportunities for the other types of solar cells applications, such as organic solar cells, c-Si solar cells, multijunction solar cells, and so on. When integrating the UC-F-TiO2 into dye-sensitized solar cells (DSSCs), superior total energy conversion efficiency was achieved. Under AM1.5G light, open-circuit voltage reached 0.77 ± 0.01 V, short-circuit current density reached 21.00 ± 0.69 mA cm(-2), which resulted in an impressive overall energy conversion efficiency of 9.91 ± 0.30%, a 37% enhancement compared to DSSCs with pristine TiO2 photoanode.

  17. Etude structurale des sulfotellurures de terres rares ( LS) 2Te 1+ x ( L = Tb, Dy, Ho, Er, Tm et Y). I. Sous-structure de la phase ordonnée de (HoS) 2Te 1,34. Structure de la phase desordonnée de (TbS) 2Te

    Science.gov (United States)

    Ghémard, G.; Etienne, J.; Flahaut, J.

    1982-11-01

    The lanthanide sulfotellurides ( LS) 2Te 1+ x (0 ≤ x < 0.50) show order-disorder phenomena. Above 450°C, they crystallize in a partially disordered structure, orthorhombic with cell parameters a, b, and c close to 4.1, 5.2, and 13.6 Å, respectively. This structure is determined from diffractometer data on a (HoS) 2Te 1.34 crystal ( R = 0.061). It is built up along the c axis from ( L4S) tetrahedra layers, separated by Te planes. Disorder and nonstoichiometry are related to the two vacant Te sites.

  18. Separation and Recycling for Rare Earth Elements by Homogeneous Liquid-Liquid Extraction (HoLLE Using a pH-Responsive Fluorine-Based Surfactant

    Directory of Open Access Journals (Sweden)

    Shotaro Saito

    2015-08-01

    Full Text Available A selective separation and recycling system for metal ions was developed by homogeneous liquid-liquid extraction (HoLLE using a fluorosurfactant. Sixty-two different elemental ions (e.g., Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, La, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Re, Rh, Ru, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tl, Tm, V, W, Y, Yb, Zn, and Zr were examined. By changing pH from a neutral or alkaline solution (pH ≥ 6.5 to that of an acidic solution (pH < 4.0, gallium, zirconium, palladium, silver, platinum, and rare earth elements were extracted at >90% efficiency into a sedimented Zonyl FSA® (CF3(CF2n(CH22S(CH22COOH, n = 6–8 liquid phase. Moreover, all rare earth elements were obtained with superior extraction and stripping percentages. In the recycling of rare earth elements, the sedimented phase was maintained using a filter along with a mixed solution of THF and 1 M sodium hydroxide aqueous solution. The Zonyl FSA® was filtrated and the rare earth elements were recovered on the filter as a hydroxide. Furthermore, the filtrated Zonyl FSA was reusable by conditioning the subject pH.

  19. Homoleptic rare earth dipyridylamides [Ln2(N(NC5H4)2)6], Ln = Ce, Nd, Sm, Ho, Er, Tm, Yb, and Sc: metal oxidation by the amine melt and in 1,2,3,4-tetrahydroquinoline with the focus of different metal activation by amalgams, liquid ammonia, and microwaves.

    Science.gov (United States)

    Müller-Buschbaum, Klaus; Quitmann, Catharina C

    2006-03-20

    Homoleptic dimeric dipyridylamide complexes of the rare earth elements are obtained by solvent-free oxidation reactions of the metals with melts of 2,2'-dipyridylamine. As the thermal stabilities of the ligand as well as the amide complexes are limiting factors in these high-temperature syntheses, several different metal activation procedures have been investigated: the formation of Ln amalgams and dissolution of the metals in liquid ammonia as well as coupling to microwaves. For comparison with a solvent that shows low solubility of the metals and products, reactions in 1,2,3,4-tetrahydroquinoline were also carried out. For all lanthanides and group 3 metals used homoleptic dimers of the formula [Ln(2)(Dpa)(6)], Ln = Ce (1), Nd (2), Sm (3), Ho (4), Er (5), Tm (6), Yb (7), and Sc (8) and Dpa- = (C5H4N)2N-, were obtained, all containing trivalent rare earth ions with a distorted square antiprismatic nitrogen coordination. Due to the large differences in the ionic radii of the metal ions, two different structure types are found that crystallize in the space groups P2(1)/c and P2(1)/n with the border of the two types being between Tm and Yb. The orientations of two 1,3/1,3-double chelating and linking dipyridylamide ligands (Dpa(-) = (C(5)H(4)N)(2)N(-)) result in different overall orientations of the dimers and thus two structure types. All compounds were identified by single-crystal X-ray analysis. Mid-IR, far IR, and Raman spectroscopy, microanalyses, and simultaneous DTA/TG as well as mass spectrometry regarding their thermal behavior were also carried out to characterize the products. Crystal data for the two types follow. Ce (1): P2(1)/n; T = 170(2) K; a = 1063.0(1), b = 1536.0(1), c = 1652.0(2) pm; beta = 101.60(1) degrees ; V = 2642.2(3) x 10(6) pm(3); R(1) for F(o) > 4sigma(F(o)) = 0.046, wR(2) = 0.120. Sc (8): P2(1)/c; T = 170(2) K; a = 1073.0(1), b = 1506.2(2), c = 1619.8(2) pm; beta = 103.16(9) degrees ; V = 2548.9(5) x 10(6) pm(3); R(1) for F(o) > 4sigma

  20. Investigation of production routes for the 161Ho Auger-electron emitting radiolanthanide, a candidate for therapy

    CERN Document Server

    Tárkányi, F; Hermanne, A; Takács, S; Ignatyuk, A V

    2013-01-01

    The radiolanthanide 161Ho (2.48 h) is a promising Auger-electron emitter for internal radiotherapy that can be produced with particle accelerators. The excitation functions of the natDy(p,xn)161Ho and natDy(d,x)161Ho reactions were measured up to 40 and 50 MeV respectively by using the stacked foil activation method and gamma-ray spectrometry. The experimental data were compared with results of the TALYS code available in the TENDL 2011 library [1]. The main parameters of different production routes are discussed.

  1. LiDy(PO34

    Directory of Open Access Journals (Sweden)

    Fathia Chehimi-Moumen

    2008-07-01

    Full Text Available Single crystals of lithium dysprosium polyphosphate, LiDy(PO34, were prepared by the flux method. The atomic arrangement is built up by infinite (PO3n chains extending along the b axis. Dy3+ and Li+ cations alternate in the middle of four such chains, with Dy...Li distances of 3.54 (1 and 3.48 (1 Å. The DyO8 dodecahedra and LiO4 tetrahedra deviate significantly from the ideal geometry. Both Dy and Li occupy special positions (Wyckoff position 4e, site symmetry 2.

  2. Luminescence studies on Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses for WLED applications

    Science.gov (United States)

    Vijayakumar, M.; Uma, V.; Arunkumar, S.; Marimuthu, K.

    2015-06-01

    Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses have been prepared and optically characterized using absorption, luminescence and decay measurements. The Nephelauxetic ratios (β), Bonding parameters (δ) and Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4 and 6) were calculated to study the nature of the environment around the RE3+ ions in the prepared glasses. The yellow to blue (Y/B) intensity ratio and the chromaticity color coordinates were calculated from the luminescence measurements. The lifetimes of the 4F9/2 excited level were measured using decay curves and is found to decrease in the Dy3+:Eu3+ co-doped glass due to the occurrence of resonant energy transfer between Dy3+-Eu3+ ions and the non-exponential decay rates have been fitted with Inokuti-Hirayama (IH) model. The decay curves are well fitted for S= 6 suggesting that the interaction between active ions for the energy transfer is of dipole-dipole nature.

  3. The magnetostriction of Tb, Dy and Ho revisited

    Energy Technology Data Exchange (ETDEWEB)

    Benito, L; Arnaudas, J I; Ciria, M; Fuente, C de la; Moral, A del [Departamento de Magnetismo de Solidos, Departamento de FIsica de la Materia Condensada-ICMA, Universidad de Zaragoza-CSIC, 50071 Zaragoza (Spain)

    2004-10-06

    In this paper we present re-analyses of magnetostriction measurements earlier performed in terbium, dysprosium and holmium single crystals. In the framework of the standard theory of single-ion crystal-electric-field and two-ion exchange magnetostrictions, we explain the thermal variation of the anisotropic saturation magnetostriction within the basal plane by considering high-order terms in the magnetoelastic energy. Using complementary basal-plane magnetic anisotropy measurements, we have been able to obtain the second- and fourth-order magnetoelastic coupling parameters associated with the orthorhombic distortion of the hexagonal plane for the above-mentioned three heavy rare earths.

  4. Fabrication, magnetostriction properties and applications of Tb-Dy-Fe alloys: a review

    Directory of Open Access Journals (Sweden)

    Nai-juan Wang

    2016-03-01

    Full Text Available As an excellent giant-magnetostrictive material, Tb-Dy-Fe alloys (based on Tb0.27-0.30Dy0.73-0.70Fe1.9-2 Laves compound can be applied in many engineering fields, such as sonar transducer systems, sensors, and micro-actuators. However, the cost of the rare earth elements Tb and Dy is too high to be widely applied for the materials. Nowadays, there are two different ways to substitute for these alloying elements. One is to partially replace Tb or Dy by cheaper rare earth elements, such as Pr, Nd, Sm and Ho; and the other is to use non-rare earth elements, such as Co, Al, Mn, Si, Ce, B, Be and C, to substitute Fe to form single MgCu2-type Laves phase and a certain amount of Re-rich phase, which can reduce the brittleness and improve the corrosion resistance of the alloy. This paper systemically introduces the development, the fabrication methods and the corresponding preferred growth directions of Tb-Dy-Fe alloys. In addition, the effects of alloying elements and heat treatment on magnetostrictive and mechanical properties of Tb-Dy-Fe alloys are also reviewed, respectively. Finally, some possible applications of Tb-Dy-Fe alloys are presented.

  5. Excitation and luminescence of Dy3+ions in PbO-P2O5-Ga2O3 glass system

    Institute of Scientific and Technical Information of China (English)

    M. Sołtys; L.Żur; J. Pisarska; W.A. Pisarski

    2014-01-01

    Lead phosphate glasses singly doped with Dy3+ions were studied. The samples were prepared in a glove box in order to eliminate hydroxyl groups. Local structures were examined using FT-IR. Excitation and luminescence spectra for Dy3+ions in inves-tigated lead phosphate glasses were registered. Luminescence intensity ratio Y/B related to 4F9/2→6HJ/2 (where J=15, 13) transitions was determined and luminescence lifetime (τm) for the 4F9/2 state of Dy3+ions were also measured.

  6. Dy substitution effect on the temperature dependences of magnetostriction in Pr1-x Dy x Fe1.9 alloys

    Science.gov (United States)

    Tang, Yan-Mei; Huang, Hai-Fu; Tang, Shao-Long; Du, You-Wei

    2016-11-01

    The temperature dependences of magnetostriction in Pr1-x Dy x Fe1.9 (0 ≤ x ≤ 1.0) alloys between 5 K and 300 K were investigated. An unusual decrease of magnetostriction with temperature decreasing was found in Pr-rich alloys (0 ≤ x ≤ 0.2), due to the change of the easy magnetization direction (EMD). Dy substitution reduces the magnetostriction in high-magnetic field (10 kOe ≤ H ≤ 90 kOe) at 5 K, while a small amount of Dy substitution (x = 0.05) is beneficial to increasing the magnetostriction in low-magnetic field between 10 K and 50 K. This makes the alloys a potential candidate for low temperature applications. Project supported by the National Natural Science Foundation of China (Grant No. U1232210), the Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant No. 2015GXNSFBA139020), and the Enhancement of the Basic Ability of Teachers of Guangxi Zhuang Autonomous Region, China (Grant No. KY2016YB068).

  7. Series of edge-sharing bi-triangle Ln4 clusters with a μ4-NO3- bridge: syntheses, structures, luminescence, and the SMM behavior of the Dy4 analogue.

    Science.gov (United States)

    Zou, Hua-Hong; Wang, Rong; Chen, Zi-Lu; Liu, Dong-Cheng; Liang, Fu-Pei

    2014-02-14

    A series of Ln4 clusters, [Ln4L2(μ3-OH)2(μ4-NO3)(NO3)4(OCH3)(H2O)]·xMeCN·yMeOH (Ln = Gd (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), L = 2-{[2-(2-hydroxy-ethoxy)-ethylimino]-methyl}-6-methoxyphenol), have been synthesized by the reaction of Ln(NO)3 and a Schiff-base ligand formed in situ. The six complexes display similar structures, with an overall metal core comprising two edge-sharing triangular Ln3 units linked by a μ4-NO3(-) bridge. The luminescence spectrum of complex 2 shows the characteristic emission of the Tb(III) ions. The magnetic susceptibility studies reveal that the Ln(III) ions are very weakly interacting in all six compounds. Frequency dependence of the ac-susceptibility was found for 3, suggesting a typical single-molecule magnet (SMM) behavior with an anisotropic barrier of 28 K.

  8. YB0 HAS LANDED

    CERN Multimedia

      On Feb 28th after a majestic descent of 90m taking 11 hours, the 2000t YB0 central wheel of CMS, containing the superconducting solenoid, gently touched down on the floor of the experimental cavern UXC55.

  9. Electronic Configuration of Yb Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Temmerman, W.M.; Szotek, Z. [Daresbury Laboratory, Daresbury, Warrington, WA4 4AD, Cheshire (United Kingdom); Svane, A. [Institute of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Strange, P. [Physics Department, Keele University, Keele, Staffordshire, ST5 5BG (United Kingdom); Winter, H. [INFP, Forschungszentrum Karlsruhe GmbH, Postfach 3640, D-76021 Karlsruhe (Germany); Delin, A.; Johansson, B.; Eriksson, O.; Fast, L. [Condensed Matter Theory Group, Department of Physics, University of Uppsala, Box 530, 75121 Uppsala (Sweden); Wills, J.M. [Center of Materials Science and Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    1999-11-01

    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. These valence energy differences correlate with the number of f electrons hybridizing with the conduction bands in the trivalent configuration. For divalent YbS, the pressure induced f -electron delocalization implies an intermediate valency, as also indicated by experiment. {copyright} {ital 1999} {ital The American Physical Society }

  10. The Dy-Zn phase diagram

    Science.gov (United States)

    Saccone, A.; Cardinale, A. M.; Delfino, S.; Ferro, R.

    2003-03-01

    The dysprosium-zinc phase diagram has been investigated over its entire composition range by using differential thermal analysis, (DTA) metallographic analysis, X-ray powder diffraction, and electron probe microanalysis (EPMA). Seven intermetallic phases have been found and their structures confirmed. DyZn, DyZn2, Dy13Zn58, and Dy2Zn17 melt congruently at 1095 °C, 1050 °C, 930 °C, and 930 °C, respectively. DyZn3, Dy3Zn11, and DyZn12 form through peritectic reactions at 895 °C, about 900 °C and 685 °C, respectively. Four eutectic reactions occur at 850 °C and 30.0 at pct Zn (between (Dy) and DyZn), 990 °C and 60.0 at pct Zn (between DyZn and DyZn2), 885 °C and 76.0 at pct Zn (between DyZn3 and Dy3Zn11), and 875 °C and 85.0 at pct Zn (involving Dy13Zn58 and Dy2Zn17). The Dy-rich end presents a catatectic equilibrium; a degenerate invariant effect has been found in the Zn-rich region. The phase equilibria of the Dy-Zn alloys are discussed and compared with those of the other known RE-Zn systems (RE=rare earth metal) in view of the regular change in the relative stabilities of the phases across the lanthanide series

  11. YB0 SERVICES INSTALLATION COMPLETED

    CERN Multimedia

    The beauty of the completed YB0 was briefly visible at P5 as preparations continue for Tracker installation. A tremendous effort, lasting 7 months and involving more than 100 workers on the busiest days, resulted in 5700 electrical cables, 780 optical cables with 65k fibre channels, and 550 pipes laid on YB0 for HB, EB and Tracker.

  12. Comparison of spectroscopic properties of Yb:YAP and Yb:YAG crystals

    Institute of Scientific and Technical Information of China (English)

    Xiaoming He; Guangjun Zhao; Xiaodong Xu; Xionghui Zeng; Jun Xu

    2007-01-01

    The Yb:YAG and Yb:YAP crystals have been grown by Czochralski method. The absorption spectra and the fluorescence spectra of Yb:YAG and Yb:YAP crystals have been investigated. It is shown that the Yb:YAG crystal has better laser properties and smaller threshold power than Yb:YAP crystal. In addition, the absorption cross-section of the Yb:YAP crystal is 2.16 times of that of the Yb:YAG crystal,so laser diode pumped Yb:YAG lasing can be easily realized. Because YAP single crystal is anisotropic, it is provided with polarization characteristics.

  13. Magnetic interactions in CuII-LnIII cyclic tetranuclear complexes: is it possible to explain the occurrence of SMM behavior in CuII-TbIII and CuII-DyIII complexes?

    Science.gov (United States)

    Hamamatsu, Takefumi; Yabe, Kazuya; Towatari, Masaaki; Osa, Shutaro; Matsumoto, Naohide; Re, Nazzareno; Pochaba, Andrzej; Mrozinski, Jerzy; Gallani, Jean-Louis; Barla, Alessandro; Imperia, Paolo; Paulsen, Carley; Kappler, Jean-Paul

    2007-05-28

    An extensive series of tetranuclear CuII2LnIII2 complexes [CuIILLnIII(hfac)2]2 (with LnIII being all lanthanide(III) ions except for the radioactive PmIII) has been prepared in order to investigate the nature of the CuII-LnIII magnetic interactions and to try to answer the following question: What makes the CuII2TbIII2 and CuII2DyIII2 complexes single molecule magnets while the other complexes are not? All the complexes within this series possess a similar cyclic tetranuclear structure, in which the CuII and LnIII ions are arrayed alternately via bridges of ligand complex (CuIIL). Regular SQUID magnetometry measurements have been performed on the series. The temperature-dependent magnetic susceptibilities from 2 to 300 K and the field-dependent magnetizations from 0 to 5 T at 2 K have been measured for the CuII2LnIII2 and NiII2LnIII2 complexes, with the NiII2LnIII2 complex containing diamagnetic NiII ions being used as a reference for the evaluation of the CuII-LnIII magnetic interactions. These measurements have revealed that the interactions between CuII and LnIII ions are very weakly antiferromagnetic if Ln=Ce, Nd, Sm, Yb, ferromagnetic if Ln=Gd, Tb, Dy, Ho, Er, Tm, and negligible if Ln=La, Eu, Pr, Lu. With the same goal of better understanding the evolution of the intramolecular magnetic interactions, X-ray magnetic circular dichroism (XMCD) has also been measured on CuII2TbIII2, CuII2DyIII2, and NiII2TbIII2 complexes, either at the L- and M-edges of the metal ions or at the K-edge of the N and O atoms. Last, the CuII2TbIII2 complex exhibiting SMM behavior has received a closer examination of its low temperature magnetic properties down to 0.1 K. These particular measurements have revealed the unusual very slow setting-up of a 3D order below 0.6 K.

  14. Concentration dependence of luminescence efficiency of Dy(3)(+) ions in strontium zinc phosphate glasses mixed with Pb3 O4.

    Science.gov (United States)

    Kumar, Valluri Ravi; Giridhar, G; Veeraiah, N

    2017-02-01

    In this work we synthesized SrO-ZnO-P2 O5 glasses mixed with Pb3 O4 (heavy metal oxide) and doped with different amounts of Dy2 O3 (0.1 to 1.0 mol%). Subsequently their emission and decay characteristics were investigated as a function of Dy2 O3 concentration. The emission spectra exhibited three principal emission bands in the visible region corresponding to (4) F9/2  → (6) H15/2 (482 nm), (6) H13/2 (574 nm) and (6) H11/2 (663 nm) transitions. With increase in the concentration of Dy2 O3 (upto 0.8 mol%) a considerable increase in the intensity of these bands was observed and, for further increase, quenching of photoluminescence (PL) output was observed. Using emission spectra, various radiative parameters were evaluated and all these parameters were found to increase with increase in Dy2 O3 concentration. The Y/B integral emission intensity ratio of Dy(3)(+) ions evaluated from these spectra exhibited a decreasing trend with increase in the Dy2 O3 concentration up to 0.8 mol%. Quenching of luminescence observed in the case of the glasses doped with 1.0 mol% is attributed to clustering of Dy(3)(+) ions. The quantitative analysis of these results together with infra-red (IR) spectral studies indicated that 0.8 mol% is the optimum concentration of Dy(3)(+) ions needed to achieve maximum luminescence efficiency. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Series of isostructural planar lanthanide complexes [Ln(III)4(mu3-OH)2(mdeaH)2(piv)8] with single molecule magnet behavior for the Dy4 analogue.

    Science.gov (United States)

    Abbas, Ghulam; Lan, Yanhua; Kostakis, George E; Wernsdorfer, Wolfgang; Anson, Christopher E; Powell, Annie K

    2010-09-06

    A series of five isostructural tetranuclear lanthanide complexes of formula [Ln(4)(mu(3)-OH)(2)(mdeaH)(2)(piv)(8)], (mdeaH(2) = N-methyldiethanolamine; piv = pivalate; Ln = Tb (1), Dy (2), Ho (3), Er (4), and Tm (5)) have been synthesized and characterized. These clusters have a planar "butterfly" Ln(4) core. Magnetically, the Ln(III) ions are weakly coupled in all cases; the Dy(4) compound 2 shows Single Molecule Magnet (SMM) behavior.

  16. Yb:S-FAP Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Schaffers, K I

    2004-01-20

    It has recently been reported that several high power, diode-pumped laser systems have been developed based on crystals of Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F]. The Mercury Laser, at Lawrence Livermore National Laboratory, is the most prominent system using Yb:S-FAP and is currently producing 23J at 5 Hz in a 15 nsec pulse, based on partial activation of the system. In addition, a regenerative amplifier is being developed at Waseda University in Japan and has produced greater than 12 mJ with high beam quality at 50Hz repetition rate. Q-peak has demonstrated 16 mJ of maximum energy/output pulse in a multi-pass, diode side-pumped amplifier and ELSA in France is implementing Yb:S-FAP in a 985 nm pump for an EDFA, producing 250 mW. Growth of high optical quality crystals of Yb:S-FAP is a challenge due to multiple crystalline defects. However, at this time, a growth process has been developed to produce high quality 3.5 cm diameter Yb:S-FAP crystals and a process is under development for producing 6.5 cm diameter crystals.

  17. Dy$^{3+}$-activated M$_2$SiO$_4$ (M $=$ Ba, Mg, Sr)-type phosphors

    Indian Academy of Sciences (India)

    ESRA ÖZTÜRK; ERKUL KARACAOGLU

    2017-02-01

    The alkaline orthosilicates of M$_2$SiO$_4$ (M $=$ Ba, Mg, Sr) activated with Dy$^{3+}$ and co-doped with Ho$^{3+}$ are prepared through conventional solid-state method, i.e., mixing and grinding of solid form precursors followedby high-temperature heat treatments of several hours in furnaces, generally under open atmosphere and investigated by X-ray diffraction (XRD) to get phase properties and photoluminescence (PL) analysis to get luminescenceproperties. The thermal behaviours of well-mixed samples were determined by differential thermal analysis (DTA)/thermogravimetry (TG). The PL spectra show that the 478 and 572nm maximum emission bands are attributed, respectively, to ${}^{4}$F$_{9/2}$ $\\to$ ${}^{6}$H$_{15/2}$ and ${}^{4}$F$_{9/2}$ $\\to$ ${}^{6}$H$_{13/2}$ transitions of Dy$^{3+}$ ions.

  18. A binuclear Fe(III)Dy(III) single molecule magnet. Quantum effects and models.

    Science.gov (United States)

    Ferbinteanu, Marilena; Kajiwara, Takashi; Choi, Kwang-Yong; Nojiri, Hiroyuki; Nakamoto, Akio; Kojima, Norimichi; Cimpoesu, Fanica; Fujimura, Yuichi; Takaishi, Shinya; Yamashita, Masahiro

    2006-07-19

    The binuclear [FeIII(bpca)(mu-bpca)Dy(NO3)4], having Single Molecule Magnet (SMM) properties, belonging to a series of isostructural FeIIILnIII complexes (Ln = Eu, Gd, Tb, Dy, Ho) and closely related FeIILnIII chain structures, was characterized in concise experimental and theoretical respects. The low temperature magnetization data showed hysteresis and tunneling. The anomalous temperature dependence of Mössbauer spectra is related to the onset of magnetic order, consistent with the magnetization relaxation time scale resulting from AC susceptibility measurements. The advanced ab initio calculations (CASSCF and spin-orbit) revealed the interplay of ligand field, spin-orbit, and exchange effects and probed the effective Ising nature of the lowest states, involved in the SMM and tunneling effects.

  19. White light simulation and luminescence studies on Dy{sup 3+} doped Zinc borophosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Vijayakumar, R. [Department of Physics, Gandhigram Rural University, Gandhigram 624302 (India); Venkataiah, G. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Marimuthu, K., E-mail: mari_ram2000@yahoo.com [Department of Physics, Gandhigram Rural University, Gandhigram 624302 (India)

    2015-01-15

    The Dy{sup 3+} doped Zinc borophosphate glasses with the chemical composition (79-x)B{sub 2}O{sub 3}+xP{sub 2}O{sub 5}+10Li{sub 2}O+10ZnO+1Dy{sub 2}O{sub 3} (where x=0, 10, 20, 30 and 50 in wt%) have been prepared by melt quenching technique. The prepared glass samples were characterized through optical absorption, emission and decay measurements. The bonding parameters, optical band gap and Urbach's energy values were calculated from the optical absorption spectra to explore the bonding nature of the Dy–O metal ligand and electronic band structure of the studied glasses. Judd–Ofelt (JO) intensity parameters were calculated from the absorption spectra by using the JO theory and it gives information about symmetry of the ligand environment around the Dy{sup 3+} ion site. The Y/B intensity ratio and radiative properties were obtained from the emission spectra and the results were compared with the reported literature. The x, y chromaticity color coordinates of the studied glasses were analyzed using a CIE 1931 color chromaticity diagram and found that the x, y coordinates lie in the white light region. The decay curve measurements of the prepared glasses exhibit non-exponential behavior and are well fitted to Inokuti–Hirayama (IH) model to understand the energy transfer mechanism between Dy{sup 3+} ions. The Q, R{sub 0} and C{sub DA} values of the prepared Dy{sup 3+} doped glasses were obtained from the IH model and the results were discussed and compared with the reported literature.

  20. Superdeformation studies in {sup 150}Tb and {sup 153}Ho

    Energy Technology Data Exchange (ETDEWEB)

    Nisius, D.; Janssens, R.V.F.; Crowell, B. [and others

    1995-08-01

    There are now over 40 superdeformed (SD) bands known in the A {approximately} 150 region and in most cases the properties of these bands are understood in terms of single-particle excitations in the absence of pairing. By continuing the search for new SD bands we hope to gain insight into (1) the ordering of the proton and neutron orbitals near the Fermi surface in the SD well, (2) the effects that the alignment of those orbitals has on the moments of inertia, and (3) the collective excitations in the SD well. For {sup 150}Tb, which is one proton and one neutron away from the SD doubly-magic nucleus {sup 152}Dy, it should be possible to study SD bands based on both proton and neutron hole excitations. By adding one proton to the {sup 152}Dy nucleus (i.e. {sup 153}Ho) proton excitations above the Z = 66 shell gap can be studied. These excitations are important as calculations suggested that the proton intruder orbital N = 7 might become occupied. Interactions between this orbital and a N = 5 level may result in softness towards octupole vibrations. High spin states in {sup 150}Th and {sup 153}Ho were populated using the {sup 124}Sn({sup 31}P,5n) and {sup 120}Sn({sup 37}Cl,4n) reactions, respectively. In both cases the early implementation phase of Gammasphere was used to detect the decay gamma rays and over 1 x 10{sup 9} triple and higher fold coincidence events were recorded. In {sup 150}Tb, the data analysis is complete and two new SD bands were identified. The fact that Im{sup (2)} moments of inertia are sensitive to the specific high-N intruder content of the SD bands was used to suggest configurations for the two new bands. A paper reporting these results is being prepared. For {sup 153}Ho, data analysis is still in its early stages.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Kyunghan [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    The family of R5SixGe4-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, R5SixGe4-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 R5SixGe4-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 R5SixGe4-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 Yb5SixGe4-xand Sm5SixGe4-x pseudobinary systems, which may exhibit mixed valence states. The crystallography, phase relationships, and physical properties of Yb5SixGe4-x alloys with 0 ≤ x ≤ 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 R5SixGe4-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 Gd5Si4-type structure. The magnetic properties of Yb5SixGe4-x materials are nearly composition

  2. The metallofullerene field-induced single-ion magnet HoSc2 N@C80.

    Science.gov (United States)

    Dreiser, Jan; Westerström, Rasmus; Zhang, Yang; Popov, Alexey A; Dunsch, Lothar; Krämer, Karl; Liu, Shi-Xia; Decurtins, Silvio; Greber, Thomas

    2014-10-13

    The low-temperature magnetic properties of the endohedral metallofullerene HoSc2 N@C80 have been studied by superconducting quantum interference device (SQUID) magnetometry. Alternating current (ac) susceptibility measurements reveal that this molecule exhibits slow relaxation of magnetization in a small applied field with timescales in the order of milliseconds. The equilibrium magnetic properties of HoSc2 N@C80 indicate strong magnetic anisotropy. The large differences in magnetization relaxation times between the present compound and the previously investigated DySc2 N@C80 are discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. ISOMER-SELECTED DECAY OF THE GDR IN DY-156

    NARCIS (Netherlands)

    VANSCHAGEN, JPS; HARAKEH, MN; HESSELINK, WHA; NOORMAN, RF

    1995-01-01

    The strength distribution of high-energy gamma-rays emitted in the statistical decay of the 156Dy compound nucleus, with E* = 92.5 MeV, has been measured inclusively and for selected decay pathways in which isomers in 149Dy, 151Dy and 152Dy were populated. For both spectra a deformation \\beta\\ = 0.3

  4. Synthesis of ZnO:Dy Nanopowder and Photoluminescence of Dy3+ in ZnO

    Institute of Scientific and Technical Information of China (English)

    Zhang Linli; Guo Changxin; Zhao Junjing; Hu Juntao

    2005-01-01

    A type of dysprosium-doped ZnO (ZnO:Dy) nanopowder was synthesized by high temperature calcinations. XRD was used to analyze the structure. Photoluminescence spectra were used to study the optical characteristic. PL of ZnO:Dy shows two different spectra which are broad band resulted from the defect of Dy in ZnO and sharp lines from the 4f→4f transition of isolated Dy3+ luminescence center. The emission and excitation spectra depend on the excitation wavelength and the concentration of Dy3+. The broad bands with peaks at 600 and 760 nm are attributed to the recombination from an electron of the defect Dy in ZnO to a hole in VB.

  5. DySectAPI: Scalable Prescriptive Debugging

    DEFF Research Database (Denmark)

    Jensen, Nicklas Bo; Karlsson, Sven; Quarfot Nielsen, Niklas;

    We present the DySectAPI, a tool that allow users to construct probe trees for automatic, event-driven debugging at scale. The traditional, interactive debugging model, whereby users manually step through and inspect their application, does not scale well even for current supercomputers. While...... lightweight debugging models scale well, they can currently only debug a subset of bug classes. DySectAPI fills the gap between these two approaches with a novel user-guided approach. Using both experimental results and analytical modeling we show how DySectAPI scales and can run with a low overhead...

  6. First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of $^{163}$Ho

    CERN Document Server

    Ranitzsch, P. C. -O.; Wegner, M.; Kempf, S.; Fleischmann, A.; Enss, C.; Gastaldo, L.; Herlert, A.; Johnston, K.

    2014-01-01

    The isotope $^{163}$Ho undergoes an electron capture process with a recommended value for the energy available to the decay, $Q_{\\rm EC}$, of about 2.5 keV. According to the present knowledge, this is the lowest $Q_{\\rm EC}$ value for electron capture processes. Because of that, $^{163}$Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the $^{163}$Dy daughter atom upon the capture of an electron from the 5s shell in $^{163}$Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the $^{163}$Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of $^{163}$Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we dis...

  7. Magnetocaloric properties of rare-earth substituted DyCrO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    McDannald, A. [Material Science and Engineering Department, University of Connecticut, Storrs, Connecticut 06269 (United States); Jain, M., E-mail: menka.jain@uconn.edu [Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States)

    2015-07-28

    Recently, there has been a focus on the need for efficient refrigeration technology without the use of expensive or harmful working fluids, especially at temperatures below 30 K. Solid state refrigeration, based on the magnetocaloric effect, provides a possible solution to this problem. The rare-earth chromites (RCrO{sub 3}), especially DyCrO{sub 3}, with its large magnetic moment dysprosium ion, are potential candidates for such an application. The Dy{sup 3+} ordering transition at low temperatures (<10 K) likely causes a large magnetocaloric response in this material. This study investigates the possibility of tuning the magnetocaloric properties through the use of rare-earth substitution. Both Y{sup 3+} and Ho{sup 3+} substitutions were found to decrease the magnetocaloric response by disrupting the R{sup 3+} ordering. Whereas Er{sup 3+} substitution was found to increase the magnetocaloric response, likely due to an increase in the R{sup 3+} ordering temperature. The large magnetocaloric entropy change of Er{sup 3+} substituted DyCrO{sub 3} (10.92 J/kg K with a relative cooling power of 237 J/kg at 40 kOe and 5 K) indicates that this material system is well suited for low temperature (<30 K) solid state refrigeration applications.

  8. Crystal structure of Tb5Ni2In4, and magnetic properties of Dy5Ni2In4

    Energy Technology Data Exchange (ETDEWEB)

    Provino, A.; Mudryk, Y.; Paudyal, D.; Smetana, V.; Manfrinetti, P.; Pecharsky, V.K.; Gschneidner Jr, Karl; Corbett, J.D.

    2012-02-27

    The crystal structure of the R5Ni2In4 intermetallic compounds was earlier reported for R Ho, Er, Tm, and Lu (Lu5Ni2In4-type, oP22, Pbam); more recently the isostructural phases Dy5Ni2In4 and Sc5Ni2In4 have also been identified. Three inequivalent crystallographic sites are occupied by the R atoms in these compounds. We have synthesized and characterized Dy5Ni2In4 and the two new isotypic compounds Tb5Ni2In4 and Y5Ni2In4. So far, none of the physical properties have been reported on any of these phases; in this article we report on the physical properties of the Dy5Ni2In4 and the crystal structure of Tb5Ni2In4 and Y5Ni2In4 compounds. Measurements of the magnetic properties performed on Dy5Ni2In4 show a ferromagnetic-like ordering with a T-C approximate to 105 K, followed by multiple magnetic orderings at lower temperatures. The fit of the inverse susceptibility in the paramagnetic state follows the Curie-Weiss law, where mu(eff). - 10.3 mu(B)/Dy-atom (close to theoretical value of 10.64 mu(B) for the free ion Dy3+) and a positive paramagnetic Curie temperature theta(p) - 58 K. Ni atoms are most likely to be nonmagnetic. The heat capacity also shows three peaks: a large one at 103K and two weaker at 12 and 8 K, respectively; the in-field heat capacity data corroborate these results, suggesting ferromagnetic and antiferromagnetic orderings at the temperature of 103 and 12 K, respectively. Low temperature x-ray diffraction has shown that the compound does not undergo any structural change down to 5K. (C) 2012 American Institute of Physics.

  9. Upconversion luminescence in Yb 3+-doped yttrium aluminum garnets

    Science.gov (United States)

    Xu, Xiaodong; Zhao, Zhiwei; Song, Pingxin; Jiang, Benxue; Zhou, Guoqing; Xu, Jun; Deng, Peizhen; Bourdet, Gilbert; Christophe Chanteloup, Jean; Zou, Ji-Ping; Fulop, Annabelle

    2005-03-01

    In this paper, we present results on upconversion luminescence performed on Yb 3+-doped yttrium aluminum garnets under 940 nm excitation. The upconversion luminescence was ascribed to Yb 3+ cooperative luminescence and the presence of rare earth impurity ions. The cooperative luminescence spectra as a function of Yb concentration were measured and the emission intensity variation with Yb concentration was discussed. Yb 3+ energy migration quenched the cooperative luminescence of Yb:YAG crystals with doping level over 15 at%.

  10. RbYb(PO34

    Directory of Open Access Journals (Sweden)

    Hui Chen

    2013-01-01

    Full Text Available Rubidium ytterbium(III tetrakis(polyphosphate, RbYb(PO34, was synthesized by solid-state reaction. It adopts structure type IV of the MRE(PO34 (M = alkali metal and RE = rare earth metal family of compounds. The structure is composed of a three-dimensional framework made up from double spiral polyphosphate chains parallel to [10-1] and irregular [YbO8] polyhedra. There are eight PO4 tetrahedra in the repeat unit of the polyphosphate chains. The Rb+ cation is located in channels extending along [100] that are delimited by the three-dimensional framework. It is surrounded by 11 O atoms, defining an irregular polyhedron.

  11. NdHO, a novel oxyhydride

    DEFF Research Database (Denmark)

    Widerøe, Marius; Fjellvåg, Helmer; Norby, Truls

    2011-01-01

    A new metal oxyhydride; neodymium oxyhydride, NdHO, has been synthesized from a reactant mixture of metal hydride (CaH2 or NdH3) and neodymium oxide(Nd2O3). The unit cell dimensions decrease smoothly in the series from LaHO, CeHO, PrHO to NdHO, in line with the lanthanide contraction. The crystal...

  12. CeNi3-type rare earth compounds: crystal structure of R3Co7Al2 (R=Y, Gd-Tm) and magnetic properties of {Gd-Er}3Co7Al2, {Tb, Dy}3Ni8Si and Dy3Co7.68Si1.32

    Science.gov (United States)

    Morozkin, A. V.; Yapaskurt, V. O.; Nirmala, R.; Quezado, S.; Malik, S. K.

    2017-03-01

    The crystal structure of new CeNi3-type {Y, Gd-Tm}3Co7Al2 (P63/mmc. N 194, hP24) compounds has been established using powder X-ray diffraction studies. The magnetism of Tb3Ni8Si and Dy3Ni8Si is dominated by rare earth sublattice and the magnetic properties of R3Co7Al2 (R =Gd-Er) and Dy3Co7.68Si1.32 are determined by both rare earth and cobalt sublattices. Magnetization data indicate ferromagnetic ordering of {Tb, Dy}3Ni8Si at 32 K and 21 K, respectively. Gd3Co7Al2 and Tb3Co7Al2 exhibit ferromagnetic ordering at 309 K and 209 K, respectively, whereas Dy3Co7Al2, Ho3Co7Al2, Er3Co7Al2 and Dy3Co7.68Si1.32 show a field dependent ferromagnetic-like ordering at 166 K, 124 K, 84 K and 226 K, respectively followed by a low temperature transition at 34 K for Dy3Co7Al2, 18 K for Ho3Co7Al2, 56 K for Er3Co7Al2, 155 K and 42 K for Dy3Co7.68Si1.32. Among these compounds, Dy3Ni8Si shows largest magnetocaloric effect (isothermal magnetic entropy change) of -11.6 J/kg·K at 18 K in field change of 50 kOe, whereas Tb3Co7Al2, Dy3Co7Al2 and Dy3Co7.68Si1.32 exhibit best permanent magnet properties in the temperature range of 2-5 K with remanent magnetization of 11.95 μB/fu, 12.86 μB/fu and 14.4 μB/fu, respectively and coercive field of 3.0 kOe, 1.9 kOe and 4.4 kOe, respectively.

  13. Optical properties of dy doped lead and bismuth borate glasses - effect of glass composition, metal and semiconducting nanoparticles

    Science.gov (United States)

    Ooi, Hio Giap

    The optical properties of Dy3+ ions in lead borate and bismuth borate glasses are studied as a function of glass composition with PbO content (29.5 to 69.5mol%) and Bi2O3 content (29.5 to 59.5 mol%). We also studied the effect of metal and semiconducting nanoparticles on the absorption and fluorescence emission of Dy3+ ions in both lead and bismuth borate glasses. The absorption coefficient at each wavelength is obtained from the optical absorption spectrum of a glass sample, and the number density of rare-earth (RE) ions is calculated from the measurement of the glass density. These two parameters are then used to calculate the oscillator strength of each transition using Judd-Ofelt theory. Using the oscillator strength for each transition, we obtained the intensity parameters which represent changes in the symmetry of the ligand field at the Dy 3+ site (due to structural group changes and changes in Dy-O covalency). Radiative transition probabilities, the radiative lifetime of the excited states and the branching ratios are then obtained from these intensity parameters. The fluorescence spectra, obtained using 355 nm and 458 nm laser excitation, are analyzed by determining the area ratio of yellow/blue (Y/B) peaks and the wavelength of the hypersensitive transition (HST). The compositional dependence and effect of nanoparticles on the stimulated emission cross-section (sigmap), are then evaluated using radiative transition probability, the refractive index of the host glass, effective fluorescence linewidth, and the position of the band. In all of the glass systems, it was found that the optical properties are strongly influenced by structural changes arising from compositional variation and size of nanoparticles. Dy 3+ transitions exhibit large sigmap suggesting the possible utilization of these materials in laser applications.

  14. XPS Studies of Yb14MnSb11 and Yb14ZnSb11

    Energy Technology Data Exchange (ETDEWEB)

    Holm, A P; Ozawa, T C; Kauzlarich, S M; Morton, S A; Waddill, G D; Pickett, W E; Tobin, J G

    2003-10-02

    Measurements of core and valence electronic states of single crystals of the rare earth transition metal Zintl phases Yb{sub 14}MnSb{sub 11} and Yb{sub 14}ZnSb{sub 11} were performed using the X-ray photoelectron spectroscopy station of Beamline 7 at the Advanced Light Source. Sample surfaces of Yb{sub 14}MnSb{sub 11} and Yb{sub 14}ZnSb{sub 11} were measured as received, after Ar{sup +} ion bombardment, and after cleaving in situ. Detailed analysis of the clean Mn and Zn analog sample surfaces reveal a significant contribution of both Yb{sup 3+} and Yb{sup 2+} 4f states in the valence band region for the Zn analog and no contribution of Yb{sup 3+} states to the valence band for the Mn analog. This result is predicted for the Zn analog by Zintl counting rules, and single crystal X-ray diffraction studies presented here also support the mixed valency of Yb for Yb{sub 14}ZnSb{sub 11}. Further detailed analysis of the core and valence band structure of both Yb{sub 14}MnSb{sub 11} and Yb{sub 14}ZnSb{sub 11} will be presented.

  15. Local symmetry lowering in the cubic intermetallics YbPdBi and YbNiSb

    Energy Technology Data Exchange (ETDEWEB)

    LeBras, G.; Bonville, P.; Hodges, J.A.; Hammann, J.; Besnus, M.J.; Schmerber, G.; Dhar, S.K.; Aliev, F.G.; Andre, G. [DRECAM/SPEC, CE Saclay, Gif-sur-Yvette (France)

    1995-07-10

    A microscopic investigation of the cubic ternary alloys YbPdBi and YbNiSb, using {sup 170}Yb Mossbauer spectroscopy, reveals that the point symmetry at the site of the Yb{sup 3+} is far from cubic in both compounds. An analysis of the thermal variation of the quadrupolar 4f moment shows that the energy of the first crystal electric field transition is close to 20 K in YbPdBi and to 10 K in YbNiSb. Specific heat measurements are also presented in YbPdBi, and magnetic ordering is detected below 1 K in YbPdBi, with saturated Yb{sup 3+} moments of 1.25 {mu}{sub B}, and below 0.85 K in YbNiSb, with saturated moments of 1 {mu}{sub B}. A tentative explanation of the Yb site symmetry breaking is made in terms of a Jahn-Teller distortion within the {gamma}{sub 8} cubic quartet. (author)

  16. Laser ablation production of Ba, Ca, Dy, Er, La, Lu, and Yb ions

    CERN Document Server

    Olmschenk, S

    2016-01-01

    We use a pulsed nitrogen laser to produce atomic ions by laser ablation, measuring the relative ion yield for several elements, including some that have only recently been proposed for use in cold trapped ion experiments. For barium, we monitor the ion yield as a function of the number of applied ablation pulses for different substrates. We also investigate the ion production as a function of the pulse energy, and the efficiency of loading an ion trap as a function of radiofrequency voltage.

  17. Photoelectron spectroscopy of strongly correlated Yb compounds

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, J.J.; Andrews, A.B.; Arko, A.J.; Bartlett, R.J.; Blythe, R.I. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Olson, C.G.; Benning, P.J.; Canfield, P.C. [Ames Laboratory, U. S. Department of Energy, Ames, Iowa 50011 (United States); Poirier, D.M. [Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    1996-12-01

    The electronic properties of the Yb compounds YBCu{sub 2}Si{sub 2}, YBAgCu{sub 4}, and YbAl{sub 3} along with purely divalent Yb metal, have been investigated by means of high-resolution ultraviolet and x-ray photoelectron spectroscopy. We present the intrinsic characteristic features of the 4{ital f} levels of Yb while accounting for lattice vibrations and the manifestation of corelike energy levels degenerate with the valence states and modified by the temperature-dependent Fermi function. For these strongly correlated Yb-based compounds, the hole occupancy values ({ital n}{sub {ital f}}{approximately}0.6) directly obtained from integration of the divalent and trivalent portions of the 4{ital f} photoemission features indicate that these compounds are strongly mixed valent. The small intensity modulation with temperature in the divalent Yb 4{ital f} levels (0{endash}10{percent} over a {ital T}=20{minus}300 K range) is discussed within the conventional framework of the photoemission process and nominal allowances for lattice variations with temperature. Results from photoemission experiments on the divalent 4{ital f} levels of strongly correlated Yb compounds are remarkably similar to the 4{ital f} levels of purely divalent Yb metal. {copyright} {ital 1996 The American Physical Society.}

  18. Scintillation properties of YAG:Yb crystals

    CERN Document Server

    Antonini, P; Carugno, Giovanni; Iannuzzi, D

    2001-01-01

    We report on measurements of the light yield, emission spectrum, and time response of YAG:Yb crystals. The temperature dependence of light yield was investigated. Data show that YAG:Yb crystals are good scintillators, suitable for applications to neutrino detection and spectroscopy.

  19. Manipulation of Dy-Mn coupling and ferrielectric phase diagram of DyMn{sub 2}O{sub 5}: The effect of Y substitution of Dy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Z. Y.; Wang, Y. L.; Lin, L.; Liu, M. F.; Li, X.; Yan, Z. B.; Liu, J.-M. [Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2015-11-07

    DyMn{sub 2}O{sub 5} is an extraordinary example in the family of multiferroic manganites and it accommodates both the 4f and 3d magnetic ions with strong Dy-Mn (4f-3d) coupling. The electric polarization origin is believed to arise not only from the Mn spin interactions but also from the Dy-Mn coupling. Starting from proposed scenario on ferrielectricity in DyMn{sub 2}O{sub 5} where the exchange-strictions associated with the Mn{sup 3+}-Mn{sup 4+}-Mn{sup 3+} blocks and Dy{sup 3+}-Mn{sup 4+}-Dy{sup 3+} blocks generate the two ferroelectric sublattices, we perform a set of characterizations on the structure, magnetism, and electric polarization of Dy{sub 1-x}Y{sub x}Mn{sub 2}O{sub 5} in order to investigate the roles of Dy-Mn coupling in manipulating the ferrielectricity. It is revealed that the non-magnetic Y substitution of Dy suppresses gradually the Dy{sup 3+} spin ordering and the Dy-Mn coupling. Consequently, the ferroelectric sublattice generated by the exchange striction associated with the Dy{sup 3+}-Mn{sup 4+}-Dy{sup 3+} blocks is destabilized, but the ferroelectric sublattice generated by the exchange striction associated with the Mn{sup 3+}-Mn{sup 4+}-Mn{sup 3+} blocks remains less perturbed, enabling the ferrielectricity-ferroelectricity transitions with the Y substitution. A phenomenological ferrielectric domain model is suggested to explain the polarization reversal induced by the Y substitution. The present work presents a possible scenario of the multiferroic mechanism in not only DyMn{sub 2}O{sub 5} but probably also other RMn{sub 2}O{sub 5} members with strong 4f-3d coupling.

  20. Preparatory studies for a high-precision Penning-trap measurement of the {sup 163}Ho electron capture Q-value

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, F. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Johannes Gutenberg-Universitaet, Institut fuer Physik, Mainz (Germany); Beyer, T.; Blaum, K.; Eibach, M.; Eliseev, S.; Nagy, Sz. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Block, M. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz-Institut Mainz, Mainz (Germany); Chenmarev, S.; Novikov, Yu.N. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Saint Petersburg State University, Physical Faculty, Saint Petersburg (Russian Federation); Dorrer, H. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Paul Scherrer Institute, Villigen (Switzerland); Universitaet Bern, Bern (Switzerland); Duellmann, C.E. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz-Institut Mainz, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany); Eberhardt, K. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Helmholtz-Institut Mainz, Mainz (Germany); Grund, J. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany); Koester, U. [Institut Laue-Langevin, Grenoble (France); Renisch, D. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Tuerler, A. [Paul Scherrer Institute, Villigen (Switzerland); Universitaet Bern, Bern (Switzerland); Wendt, K. [Johannes Gutenberg-Universitaet, Institut fuer Physik, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany)

    2015-07-15

    The ECHo Collaboration (Electron Capture {sup 163}Ho) aims to investigate the calorimetric spectrum following the electron capture decay of {sup 163}Ho to determine the mass of the electron neutrino. The size of the neutrino mass is reflected in the endpoint region of the spectrum, i.e., the last few eV below the transition energy. To check for systematic uncertainties, an independent determination of this transition energy, the Q-value, is mandatory. Using the TRIGA-TRAP setup, we demonstrate the feasibility of performing this measurement by Penning-trap mass spectrometry. With the currently available, purified {sup 163}Ho sample and an improved laser ablation mini-RFQ ion source, we were able to perform direct mass measurements of {sup 163}Ho and {sup 163}Dy with a sample size of less than 10{sup 17} atoms. The measurements were carried out by determining the ratio of the cyclotron frequencies of the two isotopes to those of carbon cluster ions using the time-of-flight ion cyclotron resonance method. The obtained mass excess values are ME({sup 163}Ho)= -66379.3(9) keV and ME({sup 163}Dy)= -66381.7(8) keV. In addition, the Q-value was measured for the first time by Penning-trap mass spectrometry to be Q = 2.5(7) keV. (orig.)

  1. Exploring the biocatalytic potential of a DyP-type peroxidase by profiling the substrate acceptance of Thermobifida fusca DyP peroxidase

    NARCIS (Netherlands)

    Loncar, Nikola; Colpa, Dana I.; Fraaije, Marco W.

    2016-01-01

    Dye-decolorizing peroxidases (DyPs) represent a new class of oxidative enzymes for which the natural substrates are largely unknown. To explore the biocatalytic potential of a DyP, we have studied the substrate acceptance profile of a robust DyP peroxidase, a DyP from Thermobifida fusca (TfuDyP). Wh

  2. Synthesis and photoluminescent characteristics of Dy3+ doped Gd2O3 phosphors

    Science.gov (United States)

    Jeena, T. R.; Ezhil Raj, A. Moses; Bououdina, M.

    2017-02-01

    Pure and dysprosium doped gadolinium oxide nanoparticles for three different concentrations (2, 5 and 10 mol.%) were synthesized by auto-combustion method using citric acid as fuel. The nanoparticles obtained were characterized using powder x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), UV–vis–NIR spectroscopy and photoluminescence (PL) spectroscopy techniques. XRD pattern revealed the crystalline cubic phase with space group Ia3 (Space Group: 206) for both the pure and doped Gd2O3 nanoparticles. The metal oxide phase formation and purity of Gd2O3 nanoparticles were further confirmed from the FTIR spectra. Morphology of the pure Gd2O3 powder is loosely dispersed clusters of tiny particles with microscopic pores, whereas for the doped samples aggregates were broken to form small clusters. Optical absorption measurements were recorded in the UV–vis–NIR wavelength region and the optical band gap variations with dopant concentration were discussed. The PL spectra of pure and Dy3+ doped Gd2O3 nanoparticles have been studied and the effect of emitted light on the yellow-to-blue intensity ratio (Y/B) of Dy3+ emission was demonstrated.

  3. Chemical co-precipitation synthesis and photoluminescence of LnP {sub x}V{sub 1-x}O{sub 4}:Dy{sup 3+} (Ln = Gd, La) derived from assembling hybrid precursors

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Bing [Department of Chemistry, Tongji University, Shanghai 200092 (China)]. E-mail: byan@tongji.edu.cn; Su, Xue-Qing [Department of Chemistry, Tongji University, Shanghai 200092 (China)

    2007-04-04

    A novel synthesis technology was applied to obtain GdP {sub x}V{sub 1-x}O{sub 4}:Dy{sup 3+} (x = 0.2, 0.3, 0.4, 0.5, 0.6, 0.7) and LaP {sub x}V{sub 1-x}O{sub 4}:Dy{sup 3+} (x = 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8) phosphors for the first time. And the doping concentration of Dy{sup 3+} ions was 3 mol.% in the two systems. Besides this, GdVO{sub 4} and LaVO{sub 4} doped with different concentration of Dy{sup 3+} ions were also synthesized. The rare earth coordination polymers with salicylic acid were used as precursors and the polyethylene glycol (PEG) was used as dispersing media. By an in situ co-precipitation process, we obtained the hybrid precursors. Both XRD and SEM indicated that the particles present good crystalline state, whose crystalline grain sizes were in the range of around 0.5-1 {mu}m. The optical properties of all the powder presented that the characteristic transitions of Dy{sup 3+} due to {sup 4}F{sub 9/2} {sup {yields}} {sup 6}H{sub 15/2} (blue) and {sup 4}F{sub 9/2} {sup {yields}} {sup 6}H{sub 13/2} (yellow) were detected. Besides this, in the system of GdP {sub x}V{sub 1-x}O{sub 4}:Dy{sup 3+}, the yellow-to-blue intensity ration (Y/B) depended on the value of P/V greatly, with the increasing of x value, the Y/B decreasing.

  4. Activation of Small Molecules by DyI_2 and Dy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results The reactivities of dysprosium diiodide and metallic dysprosium toward small molecules are discussed.For instance,DyI2-induced silyl radical reactions are described.The combination of dysprosium diiodide and dichloromethane can serve as an effective methylene transfer reagent for cyclopropanation of unfunctionalized alkenes beyond that possible with other metal-dichloromethane systems.Furthermore,we report that the combination of chlorosilane and metallic Dy can also serve as an effective prom...

  5. Time-dependent relativistic density functional study of Yb and YbO

    Institute of Scientific and Technical Information of China (English)

    XU WenHua; ZHANG Yong; LIU WenJian

    2009-01-01

    The low-lying electronic states of Yb and YbO are investigated by using time-dependent relativistic density functional theory,which is based on the newly developed exact two-component Hamiltonian resulting from symmetrized elimination of the small component.The nature of the excited states is analyzed by using the full molecular symmetry.The calculated results support the previous experimental assignment of the ground and excited states of YbO.

  6. Topics in Ho Morphophonology and Morphosyntax

    Science.gov (United States)

    Pucilowski, Anna

    2013-01-01

    Ho, an under-documented North Munda language of India, is known for its complex verb forms. This dissertation focuses on analysis of several features of those complex verbs, using data from original fieldwork undertaken by the author. By way of background, an analysis of the phonetics, phonology and morphophonology of Ho is first presented. Ho has…

  7. Topics in Ho Morphophonology and Morphosyntax

    Science.gov (United States)

    Pucilowski, Anna

    2013-01-01

    Ho, an under-documented North Munda language of India, is known for its complex verb forms. This dissertation focuses on analysis of several features of those complex verbs, using data from original fieldwork undertaken by the author. By way of background, an analysis of the phonetics, phonology and morphophonology of Ho is first presented. Ho has…

  8. DySectAPI: Scalable Prescriptive Debugging

    DEFF Research Database (Denmark)

    Jensen, Nicklas Bo; Karlsson, Sven; Quarfot Nielsen, Niklas;

    We present the DySectAPI, a tool that allow users to construct probe trees for automatic, event-driven debugging at scale. The traditional, interactive debugging model, whereby users manually step through and inspect their application, does not scale well even for current supercomputers. While...

  9. LiYbCl4(THF4

    Directory of Open Access Journals (Sweden)

    Lukas Richtera

    2011-06-01

    Full Text Available The title compound, di-μ-chlorido-dichlorido-1κ2Cl-tetrakis(tetrahydrofuran-1κ2O,2κ2O-lithiumytterbium(III, [LiYbCl4(C4H8O4], was prepared by the reaction of YbCl3(THF3 with LiCl in THF (THF is tetrahydrofuran. The central motif of the structure is a Yb(μ-Cl2Li ring. The Yb atom is hexacoordinated to four Cl atoms and two THF molecules oriented in a trans fashion. The Li atom has a tetrahedral environment and is coordinated to two Cl atoms and two THF molecules. No intermolecular interactions other than van der Waals forces were observed. Two of the THF molecules are disordered over two positions.

  10. Properties of Yb:YAG scintillators

    CERN Document Server

    Antonini, P; Bressi, G; Carugno, Giovanni; Santilli, P

    2002-01-01

    Relative light yield (LY) dependence on temperature for Yb:YAG crystals containing from 10% to 100% of Yb dopant is studied for gamma and alpha excitations. The maximum LY is achieved at 120 KYb 25%)YAG. Linearity of the light output is checked. alpha/gamma ratio is found to be 0.42+-0.02. Pulse shapes induced by gamma and alpha particles and cosmic rays are investigated by analyzing a set of single events recorded. Gamma events are fast tau<4 ns), while other kinds of radiation give rise to more complicated and longer profiles, allowing particle discrimination. Dependence of scintillation properties on concentration of Yb and purity is discussed.

  11. Effective tuning of the ratio of red to green emission of Ho{sup 3+} ions in single LiLuF{sub 4} microparticle via codoping Ce{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wei, E-mail: gaowei@xupt.edu.cn; Dong, Jun; Liu, Jihong; Yan, Xuewen

    2016-09-15

    Yb{sup 3+}/Ho{sup 3+} codoped LiLuF{sub 4} microparticles have been successfully prepared via a facile hydrothermal method. The crystal phase and morphology of LiLuF{sub 4} microparticles were inspected by x-ray diffraction and scanning electron microscope, respectively. The upconversion emission of single LiLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+} microparticle was carefully studied by a confocal microscopy setup under NIR 980 nm excitation. With the increase of Ce{sup 3+} ion concentrations of 12%, the ratio of red to green emission of the Ho{sup 3+} ions of single LiLuF{sub 4} microparticle was boosted about 17-fold, and the output colors were tuned from green to red, which is due to the two efficient cross-relaxation between Ho{sup 3+} and Ce{sup 3+} ions enhances the red and suppresses the green in the emission processes. To investigate the optical properties of the single microparticle or nanoparticle through the confocal microscopy setup can effectively avoid the influence of surrounding particle or environment, and could provide more precise information for better exploring the emission mechanisms of rare earth ions. The tunable upconversion emission of Ho{sup 3+} in single LiLuF{sub 4} microparticle in this work will have great potential applications in the micro optoelectronic devices and color display applications. - Highlights: • The optical properties of the single LiLuF4: Yb3+/Ho3+/Ce3+ microparticle were studied. • The output colors of single LiLuF4 microparticle were tuned from green to red. • The upconversion mechanisms between Ho3+ and Ce3+ ions were discussed based on emission spectrum.

  12. Optical spectra of Dy3+-doped GdVO4 and Ca3Sc2Ge3O12 crystals and evaluation of the Ω2/Ω6 ratio as a quality factor for the classification of Dy3+-activated crystalline hosts

    Science.gov (United States)

    Cavalli, Enrico

    2016-11-01

    The room temperature absorption spectra of Dy3+-doped GdVO4 and Ca3Sc2Ge3O12 crystals have been measured and analysed in the framework of the Judd-Ofelt Theory. The calculated intensity parameters have then been correlated with the intensities of the emission bands in the yellow and blue region. The analysis has then been extended to a number of host lattices using literature data, and a general empirical model has been proposed, correlating the Ω2/Ω6 and the yellow to blue (Y/B) ratio in order to define a criterion for predicting the visible luminescence properties of the Dy-activated crystalline materials.

  13. Crystal structure of Tb5Ni2In4 and Y5Ni2In4, and magnetic properties of Dy5Ni2In4

    Energy Technology Data Exchange (ETDEWEB)

    Provino, A.; Mudryk, Y.; Smetana, V.; Manfrinetti, P.; Pecharsky, V.K.; Gschneidner Jr, Karl; Corbett, J.D.

    2012-02-27

    The crystal structure of the R5Ni2In4 intermetallic compounds was earlier reported for R Ho, Er, Tm, and Lu (Lu5Ni2In4-type, oP22, Pbam); more recently the isostructural phases Dy5Ni2In4 and Sc5Ni2In4 have also been identified. Three inequivalent crystallographic sites are occupied by the R atoms in these compounds. We have synthesized and characterized Dy5Ni2In4 and the two new isotypic compounds Tb5Ni2In4 and Y5Ni2In4. So far, none of the physical properties have been reported on any of these phases; in this article we report on the physical properties of the Dy5Ni2In4 and the crystal structure of Tb5Ni2In4 and Y5Ni2In4 compounds. Measurements of the magnetic properties performed on Dy5Ni2In4 show a ferromagnetic-like ordering with a T-C approximate to 105 K, followed by multiple magnetic orderings at lower temperatures. The fit of the inverse susceptibility in the paramagnetic state follows the Curie-Weiss law, where mu(eff). - 10.3 mu(B)/Dy-atom (close to theoretical value of 10.64 mu(B) for the free ion Dy3+) and a positive paramagnetic Curie temperature theta(p) - 58 K. Ni atoms are most likely to be nonmagnetic. The heat capacity also shows three peaks: a large one at 103K and two weaker at 12 and 8 K, respectively; the in-field heat capacity data corroborate these results, suggesting ferromagnetic and antiferromagnetic orderings at the temperature of 103 and 12 K, respectively. Low temperature x-ray diffraction has shown that the compound does not undergo any structural change down to 5K. (C) 2012 American Institute of Physics

  14. Electroreduction of Ho3+ on Nickel Cathode in Molten KCl-HoCl3

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The cyclic voltammetry, open current potential-time curve after potentiostatic electrolysis, the current-time curve at potential step, XRD, EDAX and EPMA were used to study the electrode process of Ho3+ reduction on nickel electrode in molten KCl-HoCl3 and the phases of surface alloy layer. The Ho-Ni alloys were deposited when Ho3+ was reduced on the nickel electrode. The free energies of formation for the intermetallic compounds between Ho and Ni, the diffusion coefficients and diffusion activation energy of Ho atom in the alloy phase were determined.

  15. Thermochromism and fluorescence in dyed PEO films

    Energy Technology Data Exchange (ETDEWEB)

    Kamath, Archana; S, Raghu; V, Mini; C, Sharanappa; H, Devendrappa, E-mail: dehu2010@gmail.com [Dept. of Physics, Mangalore University, Managalagangothri, Mangalore--574199 (India)

    2015-06-24

    The optical absorbance spectra of solution casted pure & methyl blue (MB) dyed polyethylene oxide (PEO) films were recorded in a wavelength range from 190-1100nm at different temperatures. The absorbance was found to increases with increasing temperature. Fluorescence micrographs confirmed the interaction between polymer and dye and also revealed decreased crystallinity of the sample. Fluorescence quantum yield has been calculated with the help of fluorescence spectra.

  16. Shape coexistence in 153Ho

    CERN Document Server

    Pramanik, Dibyadyuti; Sarkar, M Saha; Bisoi, Abhijit; Ray, Sudatta; Dasgupta, Shinjinee; Chakraborty, A; Krishichayan,; Kshetri, Ritesh; Ray, Indrani; Ganguly, S; Pradhan, M K; Basu, M Ray; Raut, R; Ganguly, G; Ghugre, S S; Sinha, A K; Basu, S K; Bhattacharya, S; Mukherjee, A; Banerjee, P; Goswami, A

    2016-01-01

    The high-spin states in 153Ho, have been studied by 139 57 La(20Ne, 6n) reaction at a projectile energy of 139 MeV at Variable Energy Cyclotron Centre (VECC), Kolkata, India, utilizing an earlier campaign of Indian National Gamma Array (INGA) setup. Data from gamma-gamma coincidence, directional correlation and polarization measurements have been analyzed to assign and confirm the spins and parities of the levels. We have suggested a few additions and revisions of the reported level scheme of 153Ho. The RF-gamma time difference spectra have been useful to confirm the half-life of an isomer in this nucleus. From the comparison of experimental and theoretical results, it is found that there are definite indications of shape coexistence in this nucleus. The experimental and calculated lifetimes of several isomers have been compared to follow the coexistence and evolution of shape with increasing spin.

  17. The melting diagram of the Ti-Dy-Si system in the Ti-Ti{sub 5}Si{sub 3}-Dy{sub 5}Si{sub 3}-Dy region

    Energy Technology Data Exchange (ETDEWEB)

    Fartushna, Yu. [Frantsevich Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3 Krzhizhanovsky Street, 03142 Kiev (Ukraine)], E-mail: julia@ipms.kiev.ua; Meleshevich, K.; Samelyuk, A.; Bulanova, M. [Frantsevich Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3 Krzhizhanovsky Street, 03142 Kiev (Ukraine)

    2009-04-03

    The phase equilibria in the Ti-Ti{sub 5}Si{sub 3}-Dy{sub 5}Si{sub 3}-Dy part of the Ti-Dy-Si system were studied by DTA, X-ray diffraction, metallography and EPMA. The melting diagram, isopleths at 5Si, 65Ti and 65Dy, and a reaction scheme were constructed. The solidus surface is characterized by the following three-phase fields: <{beta}-Ti> + + DySi>, <{beta}-Ti> + DySi> + <{alpha}-Dy>, DySi> + <{alpha}-Dy> + <Dy{sub 5}Si{sub 3}>, and + DySi> + <Dy{sub 5}Si{sub 3}>. The first two fields form via U-type equilibria, L + {r_reversible} <{beta}-Ti> + DySi> and L + <{beta}-Ti> {r_reversible} DySi> + <{alpha}-Dy>, at 1320 and 1170 deg. C, respectively. The third three-phase field results from an invariant eutectic four-phase equilibrium, L {r_reversible} DySi> + <{alpha}-Dy> + <Dy{sub 5}Si{sub 3}>, at 1157 {+-} 6 deg. C. The fourth one is the result of a P-type equilibrium, L + + <Dy{sub 5}Si{sub 3}> {r_reversible} DySi>. The temperature of the latter was estimated to be within the interval 1650-1700 deg. C.

  18. Phonon Drag and Magnetic Anomalies, of Thermopower, in RB12 (R = Ho, Er, Tm, Lu)

    Science.gov (United States)

    Glushkov, V.; Demishev, S.; Ignatov, M.; Khayrullin, E.; Sluchanko, N.; Shitsevalov, N.; Levchenko, A.; Filipov, V.; Flachbart, K.; Siemensmeyer, K.

    2008-01-01

    High precision measurements of the Seebeck coefficient S(T) were carried out on the single crystals of RB12 (R = Ho, Er, Tm, Lu) at temperatures 2-300 K. It was shown that the effects of phonon drag result from vibrations of rare earth ions (ℏ ωE≈10-33 meV) in the rigid framework structure of the B12 clusters and determine the main contribution to thermopower at intermediate temperatures (30-300 K). The correlated behavior of transport parameters favors the appreciable enhancement of spin fluctuations in the sequence of magnetic compounds (HoB12-TmB12) when approaching to the valence instability state in YbB12. The giant increase in S(T) detected in the vicinity of the Néel temperature TN for HoB12, ErB12, and TmB12 seems to result from the density of states renormalization caused by antiferromagnetic ordering.

  19. Optical study of Yb{sup 3+}/Yb{sup 2+} conversion in CaF{sub 2} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kaczmarek, Slawomir M [Institute of Physics, Szczecin University of Technology, Aleja Piastow 48, 70-310 Szczecin (Poland); Tsuboi, Taiju [Faculty of Engineering, Kyoto Sangyo University, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan); Ito, Masahiko [Physical Chemistry of Luminescent Materials, Claude Bernard/Lyon 1 University, UMR CNRS 5620, Batiment A Kastler, 10 rue Ampere, 69622 Villeurbanne (France); Boulon, Georges [Physical Chemistry of Luminescent Materials, Claude Bernard/Lyon 1 University, UMR CNRS 5620, Batiment A Kastler, 10 rue Ampere, 69622 Villeurbanne (France); Leniec, Grzegorz [Institute of Physics, Szczecin University of Technology, Aleja Piastow 48, 70-310 Szczecin (Poland)

    2005-06-29

    Yb{sup 3+} ions with various site symmetries have been observed in the absorption and emission spectra of Yb{sup 3+}:CaF{sub 2} crystals, both {gamma}-irradiated and annealed in hydrogen. The absorption intensity value is found to be much higher for the {gamma}-irradiated crystal and strongly dependent on the gamma dose. The UV absorption spectra of {gamma}-irradiated and H{sub 2}-annealed CaF{sub 2}:5 at.% Yb{sup 3+} crystals are quite similar. Yb{sup 2+} absorption bands are observed at 360, 315, 271, 260, 227 and 214 nm, which are called A, B, C, D, F and G bands, respectively. For {gamma}-irradiated CaF{sub 2}:30 at.% Yb{sup 3+}, an additional band at 234 nm can be seen. It is suggested that only a negligible amount of Yb{sup 3+} ions are converted into Yb{sup 2+} under the {gamma}-irradiation. The presence of Yb{sup 2+} is confirmed by the 565 and 540 nm luminescence under 357 nm excitation. It is also suggested that the excitation in the A, C, D and F absorption bands of Yb{sup 2+} gives rise to photo-ionization of Yb{sup 2+} ions and electrons in the conduction band to form the excited Yb{sup 3+} ions which emit IR Yb{sup 3+} luminescence. The UV absorption and emission spectra obtained for {gamma}-irradiated and H{sub 2}-annealed crystals have different structures. This suggests that different mechanisms are responsible for the creation of Yb{sup 2+} ions. {gamma}-irradiation favours Yb{sup 2+} isolated centres by reduction of Yb{sup 3+} ions located at Ca{sup 2+} lattice sites, whereas annealing in hydrogen favours Yb{sup 2+} centres neighbouring Yb{sup 3+} ions when a Yb{sup 3+} ion pair captures a Compton electron. Also, {gamma}-irradiation does not change the position of Yb{sup 3+} ions converted into Yb{sup 2+} in the CaF{sub 2} lattice. In the case of H{sub 2} annealing, a Yb{sup 3+} ion converted to Yb{sup 2+} is shifted to the Ca{sup 2+} position in the lattice.

  20. Improvement of Thermal Stability of Nd-Tb-Fe-Co-B Sintered Magnets by Additions of Pr, Ho, Al, and Cu

    Directory of Open Access Journals (Sweden)

    A. A. Lukin

    2012-01-01

    Full Text Available The present work investigates the influence of Pr, Al, Cu, B and Ho which were introduced into the Co-containing sintered magnets of Nd-Dy-Tb-Fe-Co-B type on the magnetic parameters (α, Hci, Br, BHmax⁡. The effect of heat treatment parameters on magnetic properties was also studied. It was revealed that the essential alloying of NdFeB magnets by such elements as Dy, Tb, Ho, Co as well as by boron-forming elements, for example, by titanium, may lead to reducing of F-phase quantity, and, as a consequence, to decreasing of magnetic parameters. It was also shown that additional doping of such alloys by Pr, B, Al and Cu leads to a significant increase of the quantity of F-phase in magnets as well as solubility of the Dy, Tb, Ho and Co in it. This promotes the increase of magnetic parameters. It was possible to attain the following properties for the magnets (Nd0,15Pr0,35Tb0,25Ho0,2515(Fe0,71Co0,29bal ⋅ Al0,9Cu0,1B8,5 (at. % after optimal thermal treatment {1175 K (3,6–7,2 ks with slow (12–16 ks cooling to 675 K and subsequently remaining at T=775 K for 3,6 ks—hardening}: Br=0,88 T, Hci=1760 kA/m, BHmax⁡=144 kJ/m3, α<|0,01|%/K in the temperature interval 223–323 K.

  1. Magnetic and dielectric properties of YbMnO3 perovskite thin films

    Science.gov (United States)

    Rubi, D.; Venkatesan, Sriram; Kooi, B. J.; de Hosson, J. Th. M.; Palstra, T. T. M.; Noheda, B.

    2008-07-01

    Metastable manganite perovskites displaying the antiferromagnetic so-called E phase are predicted to be multiferroic. Due to the need of high pressures for the synthesis of this phase, this prediction has only been confirmed in bulk HoMnO3 . Here we report on the growth and characterization of YbMnO3 perovskite thin films grown under epitaxial strain. Highly oriented thin films, with thickness down to 30 nm, can be obtained showing magnetodielectric coupling and magnetic responses as those expected for the E phase. We observe that the magnetic properties depart from the bulk behavior only in the case of ultrathin films (d<30nm) , which display a glassy magnetic behavior. We show that strain effects alone cannot account for this difference and that the film morphology plays, instead, a crucial role.

  2. β-delayed proton decay of the proton drip-line nucleus 142Ho in the rare-earth region

    Institute of Scientific and Technical Information of China (English)

    XU; Shuwei(徐树威); LI; Zhankui(李占奎); XIE; Yuanxiang(谢元祥); XU; Furong(徐甫荣); WANG; Xudong(王旭东); GUO; Bin(郭斌); LENG; Changgeng(冷长庚); YU; Yong(于涌); WANG; Chunfang(王春芳); XING; Jianping(邢建萍); CHEN; Hongyan(陈红艳)

    2003-01-01

    New β-delayed proton precursor 142Ho was produced via heavy ion induced reaction 106Cd(40Ca, p3n), and identified for the first time by using a He-jet fast tape transport system in combination with "p-γ" coincidence measurements. The β-delayed proton decay of 142Ho was observed and its half life was determined to be (0.4±0.1) s. By fitting the experimental relative branching ratios to final states in the proton daughter nucleus 141Tb and the energy spectrum of β-delayed protons with a statistical model calculation, the ground-state spin of 142Ho was assigned as 5, 6 or 7. Nuclear energy-potential-surface (EPS) calculations were performed using the Woods-Saxon Strutinsky method. The calculated results favored the assignments of 7- to 142Ho. AS the by-products, some γ-transitions in the proton daughter nuclei following the β-delayed proton decays of precursors 139Gd, 140Tb, 142Tb, and 143Dy were reported here for the first time.

  3. Magnetic properties and XPS of Dy-Y and Dy-Nd alloys

    Institute of Scientific and Technical Information of China (English)

    戴闻; 沈保根; 李德新; 何文望; 叶小燕

    1996-01-01

    The magnetic properties and X-ray photoelectron spectroscopy (XPS) spectra in the Dy100-xYx and Dy100-zNdz rare-earth alloys are studied.The magnetism measurements show that the dhcp crystal-field influence in the Dy-Nd alloys,which tends to destroy the orbital moment,does not vanish even though a field of 6T is applied.With increasing Y (or Nd) content the temperature region corresponding to helical phase becomes wider (or narrower).The XPS records suggest that the property of the valence fluctuation in neodymium tends to increase the Fermi wave vector kF of the Dy-Nd alloys.This testifies that the abrupt dropping of the Neel temperature,as Nd is introduced,is not only due to a dilution effect of Nd.The introduction of light rare earths into heavy ones is favorable for suppressing the helical phase in the alloys and overcoming the negative magnetocaloric effect.This result will play a guiding role in designing composite magnetic refrigeration working substances.

  4. Dy3+ ions doped single and mixed alkali fluoro tungsten tellurite glasses for LASER and white LED applications

    Science.gov (United States)

    Annapurna Devi, Ch. B.; Mahamuda, Sk.; Venkateswarlu, M.; Swapna, K.; Srinivasa Rao, A.; Vijaya Prakash, G.

    2016-12-01

    A new-fangled series of Dy3+ ions doped Single and Mixed Alkali Fluoro Tungsten Tellurite Glasses have been prepared by using melt quenching technique and their spectroscopic behaviour was investigated by using XRD, optical absorption, photoluminescence and lifetime measurements. The bonding parameter studies reveal the ionic nature of the Dysbnd O bond in the present glasses. From the absorption spectra, the Judd-Ofelt (J-O) intensity parameters have been determined and in turn used to determine various radiative properties for the different emission transitions from the 4F9/2 fluorescent level. The photoluminescence spectra of all the glasses exhibit two intensified peaks in blue and yellow regions corresponding to the transitions 4F9/2 → 6H15/2 (483 nm) and 4F9/2 → 6H13/2 (575 nm) respectively. From the photoluminescence spectra, it is observed that the luminescence intensity is maximum for Dy3+ ion doped potassium combination of tungsten tellurite glass (TeWK:1Dy). The highest emission cross-section and branching ratio values observed for the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions suggest the possible laser action in the visible region from these glasses. By correlating the experimental lifetimes (τexp) measured from the decay spectral features with radiative lifetimes (τR), the quantum efficiencies (η) for all the glasses have been evaluated and found to be maximum for potassium combination tungsten tellurite (TeWK:1Dy) glass. The CIE colour chromaticity coordinates (x, y), (u, v), colour correlated temperature (CCT) and Y/B ratio were also estimated from the photoluminescence spectra for different compositions of glasses. The chromaticity colour coordinates evaluated for all the glasses fall within the white light region and white light emission can be tuned by varying the composition of the glass. From all these studies, it was concluded that 1 mol% of Dy3+ ions doped TeWK glass is more suitable for lasing and white-LED applications.

  5. Synthesis and Characterization of YB4 Ceramics

    Science.gov (United States)

    2011-06-24

    Sci., 39 [19] 5887 904 (2004). 2W. G. Fahrenholtz, G. E. Hilmas, I. G. Talmy, and J. A. Zaykoski, “Refractory Diborides of Zirconium and Hafnium ,” J...the Electronic Properties of YB4 and YB6 using 11B NMR and First-Principles Calculations,” J. Alloys Compd., 383 [1 2] 232 8 (2004). 8J. Günster, T...Compounds and Alloys ,” Akademia Nauk Ukrainskoi SSR, Kiev, 422 511 (1960) (in Russian) 15 J. F. Lynch, Engineering Properties of Selected Ceramic Materials

  6. Cryogenic Yb: YAG Thin-Disk Laser

    Science.gov (United States)

    2016-09-09

    Spitzberg, "Cryogenic Yb3+-Doped Solid-State Lasers," IEEE Journ. of Sel. Topics in Quant. Elect., 13(3), 448-459 (2007). [3] S. Tokita, J. Kawanaka, M...Europe ( IEEE ,2005) ,CTu3 (2005). [4] D. C. Brown, J. M. Singley, E. Yager, J. W. Kuper, B. J. Lotito, L. L. Bennett, "Innovative high-power CW...Y. Sun, and R. W. Equall, "Yb:YAG Absorption at Ambient and Cryogenic Temperatures," IEEE Journ. Sel. Topics Quant. Elect. 11(3), 604-612 (2005

  7. Photoassociative production of ultracold heteronuclear YbLi* molecules

    Science.gov (United States)

    Roy, Richard; Shrestha, Rajendra; Green, Alaina; Gupta, Subhadeep; Li, Ming; Kotochigova, Svetlana; Petrov, Alexander; Yuen, Chi Hong

    2016-09-01

    We report on the production of ultracold heteronuclear YbLi* molecules in a dual-species magneto-optical trap by photoassociation (PA). The formation of the electronically excited molecules close to dissociation was observed by trap loss spectroscopy. We find 4 rovibrational states within a range of 250 GHz below the Yb (S10) +Li (1/2 2P) asymptote and observe isotopic PA line shifts in mixtures of 6Li with 174Yb, 172Yb, and 176Yb. We also describe our theoretical ab initio calculation for the relevant electronic potentials and utilize it to analyze and identify the lines in the experimentally observed spectrum.

  8. Photoassociative production of ultracold heteronuclear YbLi* molecules

    CERN Document Server

    Roy, Richard; Green, Alaina; Gupta, Subhadeep; Li, Ming; Kotochigova, Svetlana; Petrov, Alexander; Yuen, Chi Hong

    2016-01-01

    We report on the production of ultracold heteronuclear YbLi* molecules in a dual-species magneto-optical trap by photoassociation (PA). The formation of the electronically excited molecules close to dissociation was observed by trap loss spectroscopy. We find 4 rovibrational states within a range of $250\\,$GHz below the Yb($^1S_0$) + Li($^2P_{1/2}$) asymptote and observe isotopic PA line shifts in mixtures of $^6$Li with $^{174}$Yb, $^{172}$Yb, and $^{176}$Yb. We also describe our theoretical ab-initio calculation for the relevant electronic potentials and utilize it to analyze and identify the lines in the experimentally observed spectrum.

  9. Prospect of TbDyFe Magnetostrictive Material

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1. Global Market: Increasing Demand for TbDyFe Mater There is steady demand for TbDyFe materials international market, especially in USA, Europe and Jap Following table shows global status of such materials si their emergence in 1984. Development course of American Etrema Company reflects the prospect of such materials. At present, besi domestic market, Etrema Company has sales subsidiarie

  10. Spectroscopic studies of Yb3+-doped rare earth orthosilicate crystals

    Science.gov (United States)

    Campos, S.; Denoyer, A.; Jandl, S.; Viana, B.; Vivien, D.; Loiseau, P.; Ferrand, B.

    2004-06-01

    Infrared transmission and Raman scattering have been used to study Raman active phonons and crystal-field excitations in Yb3+-doped yttrium, lutetium and scandium orthosilicate crystals (Y2SiO5 (YSO), Lu2SiO5 (LSO) and Sc2SiO5 (SSO)), which belong to the same C2h6 crystallographic space group. Energy levels of the Yb3+ ion 2F5/2 manifold are presented. In the three hosts, Yb3+ ions experience high crystal field strength, particularly in Yb:SSO. Satellites in the infrared transmission spectra have been detected for the first time in the Yb3+-doped rare earth orthosilicates. They could be attributed to perturbed Yb3+ sites of the lattices or to magnetically coupled Yb3+ pairs.

  11. Základní charakteristiky vína kvašeného ze samotoku a z lisovaného moštu

    OpenAIRE

    Becková, Eliška

    2010-01-01

    Tato práce se zabývá výrobou a školením bílého a červeného vína. První část je věnována teoretickými procesy a postupy při výrobě vína, popisuje sklizeň hroznů, kvašení, školení vína, chemické složení hroznů i vína, choroby a vady vína. Druhá část krátce popisuje vybrané odrůdy podrobené praktické úloze. Třetí část se zabývá praktickou výrobou vína a následně chemickými zkouškami. Odebírané mošty ze samotoku, středu lisování a dolisků byly ponechány volnému kvašení a poté byly podrobeny chemi...

  12. Thermal Expansion in YbGaGe

    OpenAIRE

    Bobev, Svilen; Williams, Darrick J.; Thompson, J.D.; Sarrao, J L

    2004-01-01

    Thermal expansion and magnetic susceptibility measurements as a function of temperature are reported for YbGaGe. Despite the fact that this material has been claimed to show zero thermal expansion over a wide temperature range, we observe thermal expansion typical of metals and Pauli paramagnetic behavior, which perhaps indicates strong sample dependence in this system.

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

    Science.gov (United States)

    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

    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.

  14. COLOR STABILITY OF NATURALLY DYED DENIM FABRICS

    Directory of Open Access Journals (Sweden)

    SUBTIRICA Adriana-Ioana

    2014-05-01

    Full Text Available The desire to colour textiles is as old as spinning and weaving. Natural dyes have been used since thousands of years for their long endurance, soft and elegant colours. But the invention of synthetic dyes has limited the application of natural dyes. The health hazards associated with the use of synthetic dyes and also the increased environmental awareness have revived the use of natural dyes during the recent years. The major performance characteristic of a dye is its ability to maintain the colour in normal use and is known as colorfastness. The study provides information regarding colour fastness properties of naturally dyed denim fabrics. Three vegetable materials were used for dyeing denim fabrics: Punica granatum (bark powder, Indigofera tinctoria (leave powder and Juglans regia (walnut dried shells. The results of the study indicated that using Walnut shells and Punica granatum deeper and more stable shades of colors are obtained in comparison with Indigofera Tinctoria dyed denim samples. All samples highlight a change in color in the sense of fading which has occurred to the highest extent when exposed to artificial light and washing. When tested against water, alkaline and acid perspiration, it is noticed that better results are obtained, and color change appear in a smaller extent.

  15. Ternary germanides RERhGe2 (RE = Y, Gd-Ho) - New representatives of the YIrGe2 type

    Science.gov (United States)

    Voßwinkel, Daniel; Heletta, Lukas; Hoffmann, Rolf-Dieter; Pöttgen, Rainer

    2016-11-01

    The YIrGe2 type ternary germanides RERhGe2 (RE = Y, Gd-Ho) were synthesized from the elements by arc-melting and characterized by powder X-ray diffraction. The structure of DyRhGe2 was refined from single crystal X-ray diffractometer data: Immm, a = 426.49(9), b = 885.0(2), c = 1577.4(3) pm, wR2 = 0.0533, 637 F2 values, 30 variables (300 K data). The structure contains two crystallographically independent dysprosium atoms in pentagonal prismatic and hexagonal prismatic coordination. The three-dimensional [RhGe2] polyanion is stabilized through covalent Rh-Ge (243-261 pm) and Ge-Ge (245-251 pm) bonding. The close structural relationship with the slightly rhodium-poorer germanides RE5Rh4Ge10 (≡ RERh0.8Ge2) is discussed. Temperature-dependent magnetic susceptibility measurements reveal Pauli paramagnetism for YRhGe2 and Curie-Weiss paramagnetism for RERhGe2 with RE = Gd, Tb, Dy and Ho. These germanides order antiferromagnetically at TN = 7.2(5), 10.6(5), 8.1(5), and 6.4(5) K, respectively.

  16. Theoretical Studies of the HO/HO2 Catalytic Cycle for Ozone Destruction

    Science.gov (United States)

    Walch, Stephen P.; Langhoff, Steve R. (Technical Monitor)

    1996-01-01

    Recently it has been determined that the HO/HO2 catalytic cycle accounts for nearly one-half of the total ozone depletion in the lower stratosphere. The catalytic cycle is: (1) HO + O3 yields HO2 + O2; (2) HO2 + O3 yields HO + O2 + O2. The net reaction is 2O3 yields 3O2. The rate limiting step in this process is the reaction of HO2 with ozone. There is a problem extending the experimental measurement of the rate of this reaction over the range 233-400 K down to stratospheric temperatures of 210-220 K. Therefore we have undertaken a project to determine the temperature dependence of the rate constant for this reaction in the low temperature region. The first step in this project, which is described in this poster, is the determination of the relevant potential energy surfaces. The calculations use CASSCF/derivative methods to define the pathways followed by CASSCF/ACPF to determine the energetics. The HO + O3 reaction is found to proceed through an HO4 complex, which is unstable with respect to HO2 + O2. The HO2 +O3 reaction is more complex. One pathway, which has been characterized, is the formation of an HO5 complex which decomposes to HO3 + O2 and subsequently to HO + O2 + O2. Another pathway, which is believed to also play a role, is hydrogen abstraction to give O2 + HO3 and subsequent decomposition of HO3 to HO + O2. Isotopic labeling experiments indicate that the later pathway is dominant. However, so far attempts to locate the saddle point for this pathway have not been successful. We have also characterized the potential energy surfaces for a number of species involved in these reactions, including HO3 and triplet O4. The triplet O4 species is probably involved in the reaction of vibrationally excited O2 with ground state O2 leading to O3 + O. The latter reaction is believed to be important as an additional source of stratospheric ozone.

  17. Investigation of luminescence and laser transition of Dy3+ ion in P2O5sbnd PbOsbnd Bi2O3sbnd R2O3 (R = Al, Ga, In) glasses

    Science.gov (United States)

    Ram, G. Chinna; Narendrudu, T.; Suresh, S.; Kumar, A. Suneel; Rao, M. V. Sambasiva; Kumar, V. Ravi; Rao, D. Krishna

    2017-04-01

    P2O5sbnd PbOsbnd Bi2O3sbnd R2O3 (R = Al, Ga, In) glasses doped with Dy2O3 were prepared by melt quenching technique. The prepared glasses were characterized by XRD, optical absorption, FTIR, luminescence studies. Judd-Ofelt parameters have been evaluated for three glass systems from optical absorption spectra and in turn radiative parameters for excited luminescent levels of Dy3+ ion are also calculated. Emission cross section and branching ratio values are observed to high for 6H13/2 level for Dy3+ ion. The yellow to blue intensity ratios and CIE chromaticity coordinates were calculated. Decay curves exhibit non exponential behavior. Quantum efficiency of prepared glasses was measured by using radiative and calculated life times. IR studies, J-O parameters and Y/B ratio values indicate that more asymmetry around Dy3+ ions in Ga2O3 mixed glass was observed. Chromaticity coordinates lie near ideal white light region. These coordinates and CCT values have revealed that all the prepared glasses emit quality white light especially the glasses mixed with Ga2O3 are suitable for development of white LEDs.

  18. [Spectroscopy parameters of Ho3+ in Ho3+ : FOG and Ho3+ : FOV].

    Science.gov (United States)

    Yang, Xiao-Dong; Chen, Ying; Chen, Xiao-Bo; Sawarobori, N; Wang, Shui-Feng; Zhou, Yong-Fen; Li, Song; Xu, Yi-Zhuang; Cheng, Huan-Li; Yang, Guo-Jian

    2013-07-01

    In the present paper, the absorption spectra of Ho3+ (0.5 mol%)-doped oxyfluoride glass (FOG) sample and Ho3+ (0.5 mol%)-doped oxyfluoride vitroceramics (FOV) sample were measured through experiment. The authors calculated the intensity parameters omega 2, 4, 6 of the two materials according to J-O theory, and analyzed the possible reason for the difference between the two materials on the intensity parameters. After that the authors calculated oscillator strength, spontaneous radiative transition rate, branching ratio and integrated emission cross section and some other spectroscopic parameters of several excited states and then made a comparative analysis of the two materials based on these spectroscopic parameters. The authors found that the oscillator strength of trivalent holmium iron in FOV is about the same with the oscillator strength in YAlO3 and is similar to oscillator strength in FOG, while slightly larger than in that LBTAF and much larger than that in LaF3 and ZBLAN. By analyzing the calculated spectroscopic parameters, it can be found that some transitions, especially 5I7 --> 5I8, 5F5 --> 5I8 etc., have a relatively large oscillator strengths(larger than 10(-6)) and large integrated emission cross sections(larger than 10(-18) cm). These transitions have the conditions to form laser passages, so they are worth a lot of attention. At last, application prospects of several strong luminescence transitions were concluded.

  19. Formation of ternary Mg–Cu–Dy bulk metallic glasses

    Indian Academy of Sciences (India)

    X F Wu; Y Kang; F F Wu; K Q Qiu; L K Meng

    2011-12-01

    The glass-forming ability (GFA) of ternary Mg–Cu–Dy alloys was systematically investigated by using differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) techniques. The results showed that a series of ternary Mg–Cu–Dy bulk metallic glasses (BGMs) with a diameter of 4–8 mm were successfully fabricated in the system with conventional Cu-mold casting method. Mg55Cu32Dy13, Mg60Cu27Dy13, Mg65Cu25Dy10 and Mg70Cu17Dy13 BMGs exhibit a clear glass transition, a broad supercooled liquid region and different crystallization and melting behaviours. They have supercooled liquid region ($\\Delta T_{x}$) from 41 K to 65 K, reduced glass transition temperature ($T_{rg}$) from 0.5363 to 0.5974 and parameter from 0.4038 to 0.4136. The shows a relatively good agreement with the GFA of the BGMs. On the other hand, a high fracture compressive strength of 624 MPa was obtained for Mg60Cu27Dy13 BMG.

  20. Search for superdeformed bands in {sup 154}Dy

    Energy Technology Data Exchange (ETDEWEB)

    Nisius, D.; Janssens, R.V.F.; Khoo, T.L. [and others

    1995-08-01

    The island of superdeformation in the vicinity of the doubly magic {sup 152}Dy yrast superdeformed (SD) band is thought to be well understood in the framework of cranked mean field calculations. In particular, the calculations suggested that in {sup 154}Dy there should be no yrast or near yrast SD minimum in the 40-60 h spin range, where SD bands in this mass region are thought to be {sup 153}Dy nucleus, it is populated. However, with the presence of five SD bands in the neighboring necessary to ascertain if the addition of one single neutron diminishes the importance of shell effects to the extent that superdeformation can no longer be sustained. In an experiment utilizing the increased resolving power of the early implementation phase of Gammasphere, the reaction {sup 122}Sn({sup 36}S,4n) at 165 MeV was employed to populate high spin states in {sup 154}Dy. In a four-day run with 36 detectors, over one billion triple and higher fold coincidence events were recorded. One new SD band was identified and was assigned to {sup 154}Dy. From comparisons with the Im{sup (2)} moments of inertia of the SD bands in {sup 152}Dy and {sup 153}Dy, a configuration based on (514)9/2{sup 2} neutrons coupled to the {sup 152}Dy SD core was proposed. One unexpected and as yet unexplained feature of this new SD band is that the transition energies are almost identical to those of an excited SD band in {sup 153}Dy. It is also worth noting that the feeding of the yrast states is similar to that achieved by the deexcitation from the ensemble of all entry states in the reaction. This observation emphasizes the statistical nature of the decay-out process. A paper reporting these results was accepted for publication.

  1. Clinical trial of {sup 166}Ho-CHICO in the treatment of rheumatoid knee synovitis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. Y.; Yoo, D. H.; Bae, S. C.; Lee, I. H.; Jung, S. S.; Jun, J. B.; Kim, T. H.; Kim, S. S. [Hanyang Univ., Seoul (Korea)

    2000-03-01

    The untreated, chronic synovial inflammation leads to pannus formation and eventual destruction of the articular cartilage. In cases where medical therapy was unsuccessful, surgical of radiation synovectomy over surgical synovectomy are (1) greater destruction of diseased synovium, (2) reduced Potential for blood clots and infection, (3) no requirement for anesthesia, and (4) less costly and less time consuming. Recently KAERI developed Dy-165 HMA, which was characterized by the absence of iron and a higher concentration of dysprosium. And then more recently KAERI also developed {sup 16H}o-CHICO, which was characterized by relatively longer half-life (26.8 hr), more biological due to organic nature of chitosan, more even spatial distribution due to colloidal solution, and more absorbable to synovium than Dy-165 HMA. These long-term follow-up results indicate that the {sup 166}Ho-CHICO is an effective and safe agent for radiation synovectomy for knee synovitis in patients with rheumatoid arthritis as well as the other chronic arthritides. But further large scaled and controlled study are required. 16 refs. (Author)

  2. Excited quasiparticles and entropy in 161,162Dy

    Science.gov (United States)

    Razavi, R.; Mohassel, A. Rashed; Mohammadi, S.

    2015-11-01

    In this paper, the nuclear level densities of 161,162Dy is studied by the use of a microscopic theory which includes nuclear pairing interaction. It is based on the modified harmonic oscillator model according to the Nilsson potential. The entropy of even-odd and even-even nuclei as a function of nuclear temperature is obtained. The entropy excess of 161Dy is compared with that of 162Dy. It is concluded that the difference is related to the entropy carried by the neutron hole coupled to the even-even core. The numbers of excited quasiparticles are calculated. Good agreement was observed between calculated results and the experimental data.

  3. Luminescence behavior of Dy 3+ ions in lead borate glasses

    Science.gov (United States)

    Pisarska, Joanna

    2009-10-01

    Dy-doped lead borate glasses were studied. The luminescence spectra showed two characteristic bands at 480 and 573 nm due to 4F 9/2- 6H 15/2 (blue) and 4F 9/2- 6H 13/2 (yellow) transitions of Dy 3+. The yellow/blue luminescence of trivalent dysprosium was analyzed as a function of the B 2O 3/PbO ratios, the activator (Dy 3+) and the PbX 2 (X = F, Cl, Br) content.

  4. Probing Dy{sup 3+} magnetic moments in multiferroic perovskite DyMnO{sub 3} by optical spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kashchenko, M.A. [Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow (Russian Federation); Moscow Institute of Physics and Technology (State University), Dolgoprudnyi (Russian Federation); Klimin, S.A.; Popova, M.N. [Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow (Russian Federation); Balbashov, A.M. [Moscow Power Engineering Institute (Technical University), Moscow (Russian Federation)

    2016-06-15

    We present a detailed temperature-dependent (4-300 K) spectroscopic study of DyMnO{sub 3} single crystals with distorted perovskite structure. Energies of 36 crystal-field levels of Dy{sup 3+} in paramagnetic DyMnO{sub 3} were determined. The Dy{sup 3+} ground Kramers doublet does not split at T{sub N}{sup Mn} = 39 K and splits below T{sub lock} = 18 K. The splitting grows fast at temperatures near T{sub N}{sup Dy} = 6.5 K and reaches Δ{sub 0} ∼ 11 ± 2 cm{sup -1} at 4 K. Using the experimental temperature dependence Δ{sub 0}(T), we calculate the dysprosium magnetic moment m{sub Dy}(T) and the dysprosium contribution into specific heat and magnetic susceptibility. Analysing all the experimental data, we conclude that the Dy-Mn interaction is of the Dzyaloshinskii-Moriya type. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. 94 β -Decay Half-Lives of Neutron-Rich Cs 55 to Ho 67 : Experimental Feedback and Evaluation of the r -Process Rare-Earth Peak Formation

    Science.gov (United States)

    Wu, J.; Nishimura, S.; Lorusso, G.; Möller, P.; Ideguchi, E.; Regan, P.-H.; Simpson, G. S.; Söderström, P.-A.; Walker, P. M.; Watanabe, H.; Xu, Z. Y.; Baba, H.; Browne, F.; Daido, R.; Doornenbal, P.; Fang, Y. F.; Gey, G.; Isobe, T.; Lee, P. S.; Liu, J. J.; Li, Z.; Korkulu, Z.; Patel, Z.; Phong, V.; Rice, S.; Sakurai, H.; Sinclair, L.; Sumikama, T.; Tanaka, M.; Yagi, A.; Ye, Y. L.; Yokoyama, R.; Zhang, G. X.; Alharbi, T.; Aoi, N.; Bello Garrote, F. L.; Benzoni, G.; Bruce, A. M.; Carroll, R. J.; Chae, K. Y.; Dombradi, Z.; Estrade, A.; Gottardo, A.; Griffin, C. J.; Kanaoka, H.; Kojouharov, I.; Kondev, F. G.; Kubono, S.; Kurz, N.; Kuti, I.; Lalkovski, S.; Lane, G. J.; Lee, E. J.; Lokotko, T.; Lotay, G.; Moon, C.-B.; Nishibata, H.; Nishizuka, I.; Nita, C. R.; Odahara, A.; Podolyák, Zs.; Roberts, O. J.; Schaffner, H.; Shand, C.; Taprogge, J.; Terashima, S.; Vajta, Z.; Yoshida, S.

    2017-02-01

    The β -decay half-lives of 94 neutron-rich nuclei Cs-151144 , Ba-154146 , La-156148 , Ce-158150 , Pr-160153 , Nd-162156 , Pm-163159 , Sm-166160 , Eu-168161 , Gd-170165 , Tb-172166 , Dy-173169 , Ho-175172 , and two isomeric states Erm174 , Dym172 were measured at the Radioactive Isotope Beam Factory, providing a new experimental basis to test theoretical models. Strikingly large drops of β -decay half-lives are observed at neutron-number N =97 for Ce 58 , Pr 59 , Nd 60 , and Sm 62 , and N =105 for Eu 63 , Gd 64 , Tb 65 , and Dy 66 . Features in the data mirror the interplay between pairing effects and microscopic structure. r -process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system.

  6. Shape Co-Existence in the Transitional Nuclide 157Yb

    Institute of Scientific and Technical Information of China (English)

    徐川; 华辉; 李湘庆; 张双全; 许甫荣; 石跃; 竺礼华; 吴晓光; 李广生; 贺创业

    2012-01-01

    High-spin states in 157Yb have been populated in the 144Sm(160, 3n)157yb fusion- evaporation reaction at a beam energy of 85 MeV, and two rotational bands have been established for the first time. Within the framework of the triaxial particle-rotor model, the energy spectra and single-particle configurations of 157Yb are investigated. The calculated energy spectra agree well with the experimental data. The newly observed vf7/2 band, and the previously known vi13/2 band in 157Yb, are also discussed by means of Total-Routhian-Surface methods. The structural characters observed in 157Yb provide evidence for the shape coexistence of three distinct shapes: prolate, triaxial and oblate. At higher spins, both the vf7/2 band and the vi13/2 band in 157Yb undergo a shape evolution with sizable alignments occurring.

  7. A trimetallic strategy towards ZnDyCr and ZnDyCo single-ion magnets.

    Science.gov (United States)

    Hu, Kong-Qiu; Jiang, Xiang; Wu, Shu-Qi; Liu, Cai-Ming; Cui, Ai-Li; Kou, Hui-Zhong

    2015-09-21

    Two cyano- and phenoxo-bridged octanuclear complexes ZnDyCo (complex ) and ZnDyCr (complex ) with diamagnetic Zn(ii) and Co(iii) are reported. Dy(iii) is surrounded by nine oxygen atoms of two [Zn(Me2valpn)] (Me2valpn(2-) = dianion of N,N'-2,2-dimethylpropylenebis(3-methoxysalicylideneimine)) and one water molecule. Magnetic studies reveal that both exhibit single-ion magnet (SIM) behavior with the energy barrier of 85.9 K for complex and 100.9 K for complex .

  8. X-ray analysis and optical studies of Dy{sup 3+} doped NaSrB{sub 5}O{sub 9} microstructures for white light generation

    Energy Technology Data Exchange (ETDEWEB)

    Dillip, G.R. [School of Mechanical Engineering and Technology, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Ramesh, B.; Madhukar Reddy, C.; Mallikarjuna, K.; Ravi, O. [Department of Physics, Sri Venkateswara University, Tirupati 517 502 (India); Dhoble, S.J. [Department of Physics, RTM Nagpur University, Nagpur 440 033 (India); Joo, S.W. [School of Mechanical Engineering and Technology, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Raju, B. Deva Prasad, E-mail: drdevaprasadraju@gmail.com [Department of Future Studies, Sri Venkateswara University, Tirupati 517 502 (India)

    2014-12-05

    Highlights: • NaSrB{sub 5}O{sub 9}:Dy{sup 3+} microstructures were synthesized by solid state reaction. • Crystallite size and lattice strain was estimated by W–H analysis. • Plate-like morphology with monoclinic structure is identified by SEM images. • Highest lifetimes of 931 μS were obtained for this system. - Abstract: A white light emitting phosphor NaSrB{sub 5}O{sub 9}:Dy{sup 3+} was synthesized by a conventional solid state reaction method. The structure of the phosphors was analyzed by powder X-ray diffraction (XRD), revealing that the phosphors crystallized in monoclinic crystal structure with the space group (P2{sub 1}/c). Williamson–Hall (W–H) analysis was used to study the individual contributions of crystallite sizes and lattice strain on the peak broadening of NaSrB{sub 5}O{sub 9}:Dy{sup 3+} phosphors. Monoclinic microstructures of nearly plate-like morphologies were observed in the FE-SEM images. Upon near-UV excitation wavelength (390 nm), the blue emission at ∼482 nm ({sup 6}H{sub 15/2}) and yellow emission at ∼584 nm ({sup 6}H{sub 13/2}) were observed in the phosphors. The critical quenching concentration of Dy{sup 3+} in NaSrB{sub 5}O{sub 9} phosphor was found to be 3 at.% with the critical distance (R{sub c}) of ∼22.30 Å and the corresponding concentration quenching mechanism was testified to be the exchange interaction between the dopant Dy{sup 3+} ions. In order to investigate the application in white LEDs, the Commission International de l’Eclairage (CIE) chromaticity coordinates, color temperature and decay curve measurements of Dy{sup 3+} ions doped NaSrB{sub 5}O{sub 9} phosphors were carried out. The yellow to blue (Y/B) emission integrated intensity ratio is maximum (∼0.9) for all the concentrations, suggesting that the phosphors favor for white illumination.

  9. X-ray photoelectron spectroscopy and magnetism of AlDyNi, AlDyNi{sub 4} and AlDy{sub 3}Ni{sub 8} compounds

    Energy Technology Data Exchange (ETDEWEB)

    Rednic, V; Coldea, M; Rednic, L; Pascut, L G; Pintea, S [Babes-Bolyai University, Faculty of Physics, 1 Mihail Kogalniceanu, 400084 Cluj-Napoca (Romania); Aldea, N [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Neumann, M, E-mail: vasile.rednic@itim-cj.r [University of Osnabrueck, Fachbereich Physik, 49069 Osnabrueck (Germany)

    2009-08-01

    The electronic and magnetic properties of AlDyNi, AlDyNi{sub 4} and AlDy{sub 3}Ni{sub 8} are studied using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), static and dynamic magnetic measurements. The three compounds AlDyNi, AlDyNi{sub 4} and AlDy{sub 3}Ni{sub 8} are single phases and crystallize in the Fe{sub 2}P, CaCu{sub 5} and CeNi{sub 3} structure types, respectively. All the investigated compounds order ferromagnetically below the corresponding Curie temperatures. The Curie temperature and the magnetic moments are 25 K and 6 {mu}{sub B}/f.u. for AlDyNi, 14 K and 6.9 {mu}{sub B}/f.u. for AlDyNi{sub 4} and 22K and 19.2 {mu}{sub B}/f.u. for AlDy{sub 3}Ni{sub 8}. At high temperature the magnetic susceptibility obey the Curie-Weiss law. The paramagnetic Curie temperature and the effective magnetic moments are 30K and 10.88 {mu}{sub B}/f.u. for AlDyNi, 28 K and 10.94 {mu}{sub B}/f.u. for AlDyNi{sub 4} and 18 K and 18.33 {mu}{sub B}/f.u. for AlDy{sub 3}Ni{sub 8}. XPS valence band and Ni 2p spectra indicated the presence of small magnetic moment on Ni sites in AlDy{sub 3}Ni{sub 8} and AlDyNi{sub 4}, and a complete filling of Ni 3d band in AlDyNi.

  10. Isothermal section at 850 °C of the Ti–Dy–Al system in the Ti–TiAl–DyAl{sub 2}–Dy region

    Energy Technology Data Exchange (ETDEWEB)

    Bulanova, M.; Fartushna, I., E-mail: juliefart@mail.ru; Meleshevich, K.; Samelyuk, A.

    2014-06-15

    Highlights: • By the character the isothermal section at 850 °C is practically similar to the solidus surface. • The phases α{sup l}, α{sub 2} and αDyAl{sub 2} define the character of phase equilibria. • Among all phases only (αDyAl{sub 2}) dissolves significant amount of third component. • The solubility of titanium in αDyAl{sub 2} is about 19 at.%. • The ternary compounds in the studied region were not found. - Abstract: Phase equilibria in the Ti–Dy–Al system in the Ti–TiAl–DyAl{sub 2}–Dy region at 850 °C were studied by the methods of X-ray diffraction, SEM and electron microprobe. The isothermal section at this temperature was constructed. The ternary compounds in the studied region were not found. The isothermal section at 850 °C is characterized by the three-phase regions α{sup l} + (αDy) + (Dy{sub 2}Al), α{sup l} + α{sub 2} + (Dy{sub 2}Al), α{sub 2} + (Dy{sub 2}Al) + (Dy{sub 3}Al{sub 2}), α{sub 2} + (Dy{sub 3}Al{sub 2}) + (αDyAl{sub 2}), (DyAl) + (αDyAl{sub 2}) + (Dy{sub 3}Al{sub 2}) and α{sub 2} + (αDyAl{sub 2}) + γ and appropriate two-phase areas.

  11. Search for excited superdeformed bands in {sup 151}Dy

    Energy Technology Data Exchange (ETDEWEB)

    Nisius, D.; Janssens, R.V.F.; Crowell, B. [and others

    1995-08-01

    Following the first report of superdeformed (SD) bands with identical transition energies in the pairs ({sup 151}Tb*,{sup 152}Dy), ({sup 150}Gd*, {sup 151}Tb) and ({sup 153}Dy*, {sup 152}Dy) (where * denotes an excited SD band), it was proposed by Nazarewicz et al. that the observations could be understood in a strong-coupling approach if pseudo SU(3) symmetry were invoked. In this model there are three limiting values of the decoupling parameter; i.e. a = 0, {plus_minus}1. In the first two cases mentioned above the pairs of bands have nearly identical transition energies and are interpreted as proton excitations involving the [200]1/2 pseudospin orbital coupled to the {sup 152}Dy core, for which the value of the decoupling parameter is calculated to be a =+1.

  12. Light and anoxia fading of Prussian blue dyed textiles

    National Research Council Canada - National Science Library

    Gervais, Claire; Languille, Marie-Angélique; Reguer, Solenn; Garnier, Chantal; Gillet, Martine

    2014-01-01

    .... Its stability upon exposure to light and anoxia remains difficult to apprehend. The present paper focuses on the relative influences of light, anoxia and type of substrate on the discoloration of Prussian blue dyed textiles...

  13. High-spin structure of neutron-rich Dy isotopes

    Indian Academy of Sciences (India)

    A Ansari; H L Yadav; M Kaushik; U R Jakhar

    2003-06-01

    In view of recent experimental progress on production and spectroscopy of neutron-rich isotopes of Dy with mass number = 166 and 168, we have made theoretical investigations on the structure of high spin states of 164-170Dy isotopes in the cranked Hartree–Fock–Bogoliubov (CHFB) theory employing a pairing+quadrupole+hexadecapole model interaction. With the increase of neutron number the rotation alignment of the proton orbitals dominates the structure at high spins, which is clearly reflected in the spin dependence of the rotational g-factors. A particularly striking feature is the difference in the spin-dependent properties of 166Dy as compared to that of 164Dy.

  14. Green Non-dyed Textile Innovation Alliance officially launched

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    June 29, the Green Non-dyed Textile Innovation Alliance was officially launched by the China Textile Information Center, Nationa Textile Product Development Center together with China Chemical Fiber Industry Association

  15. Cryogenic Yb:YAG thin-disk laser

    Science.gov (United States)

    Vretenar, N.; Carson, T.; Lucas, T.; Newell, T.; Latham, W. P.; Peterson, P.; Bostanci, H.; Lindauer, J. J.; Saarloos, B. A.; Rini, D. P.

    2011-11-01

    At cryogenic temperatures, Yb:YAG behaves as a 4-level laser. Its absorption and emission cross-sections increase, and its thermal conductivity improves. Yb:YAG thin disk laser performance at room and cryogenic (80°K) temperatures will be presented. The Yb:YAG gain media is cooled using either a pressurized R134A refrigerant system or by a two-phase liquid nitrogen spray boiler. Interchangeable mounting caps allow the same Yb:YAG media to be switched between the two systems. This allows direct comparison of lasing, amplified spontaneous emission, and temperature performance between 20°C and -200°C.

  16. Power scaling of cryogenic Yb:LiYF(4) lasers.

    Science.gov (United States)

    Zapata, Luis E; Ripin, Daniel J; Fan, Tso Yee

    2010-06-01

    We demonstrate a cryogenically cooled Yb:LiYF(4) (Yb:YLF) laser with 224W linearly polarized output power (pump-power limited) and a slope efficiency of 68%. The beam quality is characterized by an M(2) approximately 1.1 at 60W output and M(2) approximately 2.6 at 180W output. This level of average laser power is approximately 2 orders of magnitude higher than demonstrated previously in cryogenic Yb:YLF. Yb:YLF is attractive for femtosecond pulse generation because of its wide gain bandwidth, and this demonstration shows the potential for high-average-power subpicosecond pulse lasers.

  17. Ultrasonic study of the Yb-based heavy fermion compound YbRh{sub 2}Zn{sub 20}

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Y; Ito, K; Nakamura, M; Yoshizawa, M [Graduate School of Engineering, Iwate University, Morioka 020-8551 (Japan); Saiga, Y; Kosaka, M [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Uwatoko, Y, E-mail: yoshiki@iwate-u.ac.j [Institute for Solid State Physics, University of Tokyo, Kashiwa 227-8581 (Japan)

    2009-03-01

    We report ultrasonic measurements on the high quality single crystal of the Yb-based heavy fermion compound YbRh{sub 2}Zn{sub 20} over a temperature range from 200 K to 0.5 K. A shallow, but clear minimum was observed in the temperature dependent elastic constants C{sub 11}, (C{sub 11} - C{sub 12})/2 and C{sub 44} around 15 K, probably attributed to the ground state and low-lying excited states of Yb{sup 3} in the cubic CEF. We discuss the low-temperature elastic properties and possible energy level scheme of localized 4f state of Yb{sup 3} ions in YbRh{sub 2}Zn{sub 20}. CEF ground state developed at the low temperatures and physical parameters relating to a quadrupolar moment in YbRh{sub 2}Zn{sub 20}

  18. YB-1 protein: functions and regulation.

    Science.gov (United States)

    Lyabin, Dmitry N; Eliseeva, Irina A; Ovchinnikov, Lev P

    2014-01-01

    The Y-box binding protein 1 (YB-1, YBX1) is a member of the family of DNA- and RNA-binding proteins with an evolutionarily ancient and conserved cold shock domain. It falls into a group of intrinsically disordered proteins that do not follow the classical rule 'one protein-one function' but introduce a novel principle stating that a disordered structure suggests many functions. YB-1 participates in a wide variety of DNA/RNA-dependent events, including DNA reparation, pre-mRNA transcription and splicing, mRNA packaging, and regulation of mRNA stability and translation. At the cell level, the multiple activities of YB-1 are manifested as its involvement in cell proliferation and differentiation, stress response, and malignant cell transformation. WIREs RNA 2014, 5:95-110. doi: 10.1002/wrna.1200 CONFLICT OF INTEREST: The authors have declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website.

  19. The Calculation of Ho Production by indirect Method and Preparation of Polymeric Microsphere for Radioembolisation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, K. H.; Kim, J. B.; Park, U. J.; Cho, E. H.; Nam, S. S.; Yoo, K. M.; Jang, K. D. [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The reactor-produced radiolanthanides have been essential for development of therapeutic radiopharmaceuticals because they emit proper beta energies to induce tumor necrosis. Some radiolanthanides are very useful in that they have the ability of simultaneous diagnosis and therapeutic effect. This nuclide with both capacities is called as theranostic nuclide. In general, radiolanthanides can be produced by (n,γ) and (n,γ)β reaction. Of the two reactions, (n,γ)β reaction-product, shows high specific activity which is important things to affect labeling yield, is suitable for preparing the radiophamaceuticals comprising the antibody or peptide. Some radiolanthanides show the good theranostic effect in that they have proper LET (Linear Energy Transfer) to induce apoptosis for cancer and gamma ray to use as a tracer for cancer diagnosis. Although Ho-166 has been studied for therapeutic purpose since early 1990, production has been limited to direct method. To inject Dy/Ho mixture into the microsphere, we first set-up the concepts which are prior metal-administration method and posterior administration method. The latter is shown in this paper. Metal inletting process was done by using alternating between vacuum and pressurization. To prevent the leak of metal ions from metal/microsphere hybrid, surface coating was done by using interfacial reaction between saline and THF contained Poly lactic acid. Surface coating is simply completed just swiveling the vial. All experiments in this study, we just only tested with cold state.

  20. Comparison of the sequence-dependent fluorescence of the cyanine dyes Cy3, Cy5, DyLight DY547 and DyLight DY647 on single-stranded DNA.

    Science.gov (United States)

    Kretschy, Nicole; Somoza, Mark M

    2014-01-01

    Cyanine dyes are commonly used for fluorescent labeling of DNA and RNA oligonucleotides in applications including qPCR, sequencing, fluorescence in situ hybridization, Förster resonance energy transfer, and labeling for microarray hybridization. Previous research has shown that the fluorescence efficiency of Cy3 and Cy5, covalently attached to the 5' end of single-stranded DNA, is strongly sequence dependent. Here, we show that DY547 and DY647, two alternative cyanine dyes that are becoming widely used for nucleic acid labeling, have a similar pattern of sequence-dependence, with adjacent purines resulting in higher intensity and adjacent cytosines resulting in lower intensity. Investigated over the range of all 1024 possible DNA 5mers, the intensities of Cy3 and Cy5 drop by ∼ 50% and ∼ 65% with respect to their maxima, respectively, whereas the intensities of DY547 and DY647 fall by ∼ 45% and ∼ 40%, respectively. The reduced magnitude of change of the fluorescence intensity of the DyLight dyes, particularly of DY647 in comparison with Cy5, suggests that these dyes are less likely to introduce sequence-dependent bias into experiments based on fluorescent labeling of nucleic acids.

  1. Comparison of the sequence-dependent fluorescence of the cyanine dyes Cy3, Cy5, DyLight DY547 and DyLight DY647 on single-stranded DNA.

    Directory of Open Access Journals (Sweden)

    Nicole Kretschy

    Full Text Available Cyanine dyes are commonly used for fluorescent labeling of DNA and RNA oligonucleotides in applications including qPCR, sequencing, fluorescence in situ hybridization, Förster resonance energy transfer, and labeling for microarray hybridization. Previous research has shown that the fluorescence efficiency of Cy3 and Cy5, covalently attached to the 5' end of single-stranded DNA, is strongly sequence dependent. Here, we show that DY547 and DY647, two alternative cyanine dyes that are becoming widely used for nucleic acid labeling, have a similar pattern of sequence-dependence, with adjacent purines resulting in higher intensity and adjacent cytosines resulting in lower intensity. Investigated over the range of all 1024 possible DNA 5mers, the intensities of Cy3 and Cy5 drop by ∼ 50% and ∼ 65% with respect to their maxima, respectively, whereas the intensities of DY547 and DY647 fall by ∼ 45% and ∼ 40%, respectively. The reduced magnitude of change of the fluorescence intensity of the DyLight dyes, particularly of DY647 in comparison with Cy5, suggests that these dyes are less likely to introduce sequence-dependent bias into experiments based on fluorescent labeling of nucleic acids.

  2. Yb3+ Ion Upconversion Luminescence from YbEr:ZBLAN Glass Excited by 966 nm Laser Light

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-Bo; NIE Yu-Xin; WEN Ou

    2001-01-01

    The upconversion lumiuescence of several YbEr co-doped Zr-Ba-La-AI-Na (ZBLAN) glass samples (Er(0.5) Yb(3): ZBLAN, Er(0.5)Yb(1):ZBLAN and Er(0.5):ZBLAN) has been studied. A new kind of upconversion cooperative radiation fluorescence, which comes from coupled cluster states of two Yb3+ ions has been observed. This is significant in that it may lead to a new path to achieve blue upconversion luminescence, which has promising upconversion applications.

  3. Chemical Bond Parameters in Sr3MRhO6 (M=Rare earth)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Chemical bond parameters, that is, bond covalency, bond valence, macroscopic linear susceptibility, and oxidation states of elements in Sr3MRhO6 (M=Sm, Eu, Tb, Dy, Ho, Er, Yb) have been calculated. The results indicate that the bond covalency of M-O decreases sharply with the decrease of ionic radius of M3+ from Sm to Yb, while no obvious trend has been found for Rh-O and Sr-O bonds. The global instability index indicates that the crystal structures of Sr3MrhO6 (M = Sm, Eu, Tb, Dy, Ho) have strained bonds.

  4. The Unimolecular Decomposition and H Abstraction Reactions by HO and HO2 from n-Butanol

    Science.gov (United States)

    Moc, Jerzy; Black, Gráinne; Simmie, John M.; Curran, Henry J.

    2009-08-01

    By using correlated ab initio (MP2, CCSD(T)) and multi-level (G3, CBS-QB3) methods we have studied unimolecular and bimolecular reactions of n-butanol in the gas phase. The specific processes investigated include H2O elimination and hydrogen abstraction by the hydroxy (HO) and hydroperoxy (HO2) radicals from this alcohol.

  5. Delayed cutaneous wound closure in HO-2 deficient mice despite normal HO-1 expression

    NARCIS (Netherlands)

    Lundvig, D.M.S.; Scharstuhl, A.; Cremers, N.A.J.; Pennings, S.W.C.; Paske, J. Te; Rheden, R. van; Breda, C. van Run-van; Regan, R.F.; Russel, F.G.M.; Carels, C.E.L.; Maltha, J.C.; Wagener, F.A.D.T.G.

    2014-01-01

    Impaired wound healing can lead to scarring, and aesthetical and functional problems. The cytoprotective haem oxygenase (HO) enzymes degrade haem into iron, biliverdin and carbon monoxide. HO-1 deficient mice suffer from chronic inflammatory stress and delayed cutaneous wound healing, while corneal

  6. Demonstration of a hybrid Ho:YLF Ho:LuLF slab laser

    CSIR Research Space (South Africa)

    Esser, MJD

    2010-10-01

    Full Text Available The authors present a continuous-wave slab laser utilising both Ho:YLF and Ho:LuLF as laser gain media. 30 W of output power at 2 µm was demonstrated in a stable concave-plane resonator while 13 W was achieved in a hybrid stable...

  7. Delayed cutaneous wound closure in HO-2 deficient mice despite normal HO-1 expression

    NARCIS (Netherlands)

    Lundvig, D.M.S.; Scharstuhl, A.; Cremers, N.A.J.; Pennings, S.W.C.; Paske, J. Te; Rheden, R. van; Breda, C. van Run-van; Regan, R.F.; Russel, F.G.M.; Carels, C.E.L.; Maltha, J.C.; Wagener, F.A.D.T.G.

    2014-01-01

    Impaired wound healing can lead to scarring, and aesthetical and functional problems. The cytoprotective haem oxygenase (HO) enzymes degrade haem into iron, biliverdin and carbon monoxide. HO-1 deficient mice suffer from chronic inflammatory stress and delayed cutaneous wound healing, while corneal

  8. New orthorhombic derivative of CaCu{sub 5}-type structure: RNi{sub 4}Si compounds (R=Y, La, Ce, Sm, Gd–Ho), crystal structure and some magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Morozkin, A.V., E-mail: morozkin@general.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India)

    2013-12-15

    The crystal structure of new YNi{sub 4}Si-type RNi{sub 4}Si (R=Y, La, Ce, Sm, Gd–Ho) compounds has been established using powder X-ray diffraction. The YNi{sub 4}Si structure is a new structure type, which is orthorhombic derivative of CaCu{sub 5}-type structure (space group Cmmm N 65, oC12). GdNi{sub 4}Si and DyNi{sub 4}Si compounds order ferromagnetically at 25 and 19 K, respectively whereas YNi{sub 4}Si shows antiferromagnetic nature. At 15 K, DyNi{sub 4}Si shows second antiferromagnetic-like transition. The magnetic moment of GdNi{sub 4}Si at 5 K in 50 kOe field is ∼7.2 μ{sub B}/f.u. suggesting a completely ordered ferromagnetic state. The magnetocaloric effect of GdNi{sub 4}Si is calculated in terms of isothermal magnetic entropy change and it reaches the maximum value of −12.8 J/kg K for a field change of 50 kOe near T{sub C} ∼25 K. - Graphical abstract: The RNi{sub 4}Si (R=Y, La, Ce, Sm, Gd–Ho) compounds crystallize in new YNi{sub 4}Si-type structure which is orthorhombic derivative of the basic CaCu{sub 5}-type structure. GdNi{sub 4}Si and DyNi{sub 4}Si compounds show the ferromagnetic-like ordering, whereas.YNi{sub 4}Si has the antiferromagnetic nature. The GdNi{sub 4}Si demonstrates the big magnetocaloric effect near temperature of ferromagnetic ordering. The relationship between initial CaCu{sub 5}-type DyNi{sub 5} and YNi{sub 4}Si-type DyNi{sub 4}Si lattices.

  9. Structure induced Yb valence changes in the solid solution Yb(x)Ca(1-x)C2.

    Science.gov (United States)

    Link, Pascal; Glatzel, Pieter; Kvashnina, Kristina; Trots, Dmytro M; Smith, Ronald I; Ruschewitz, Uwe

    2013-06-17

    The solid solution Yb(x)Ca(1-x)C2 (0 ≤ x ≤ 1) was synthesized by reaction of the elements at 1323 K. The crystal structures within this solid solution, as elucidated from synchrotron powder diffraction data, depend on x and exhibit some interesting features that point to a structure dependent valence state of Yb. Compounds with x ≥ 0.75 crystallize in the tetragonal CaC2 type structure (I4/mmm, Z = 2) and obey Vegard's law; for x ≤ 0.75 the monoclinic ThC2 type structure (C2/c, Z = 4) is found, which coexists with the monoclinic CaC2-III type structure (C2/m, Z = 4) for x ≤ 0.25. The monoclinic modifications show a strong deviation from Vegard's law. Their unit cell volumes are remarkably larger than expected for a typical Vegard system. HERFD-XANES spectroscopic investigations reveal that different Yb valence states are responsible for the observed volume anomalies. While all tetragonal compounds contain mixed-valent Yb with ∼75% Yb(3+) (similar to pure YbC2), all monoclinic modifications contain exclusively Yb(2+). Therefore, Yb(x)Ca(1-x)C2 is a very rare example of a Yb containing compound showing a strong structure dependence of the Yb valence state. Moreover, temperature dependent synchrotron powder diffraction, neutron TOF powder diffraction, and HERFD-XANES spectroscopy experiments reveal significant Yb valence changes in some compounds of the Yb(x)Ca(1-x)C2 series that are induced by temperature dependent phase transitions. Transitions from the tetragonal CaC2 type structure to the monoclinic ThC2 or the cubic CaC2-IV type structure (Fm3m, Z = 4) are accompanied by drastic changes of the mean Yb valence from ∼2.70 to 2.0 in compounds with x = 0.75 and x = 0.91. Finally, the determination of lattice strain arising inside the modifications with ordered dumbbells (ThC2 and CaC2 type structures) by DSC measurements corroborated our results concerning the close relationship between crystal structure and Yb valence in the solid solution Yb(x)Ca(1-x

  10. Thermodynamic assessment of Ni-Yb binary system%Ni-Yb 二元系的热力学评估

    Institute of Scientific and Technical Information of China (English)

    朱代漫; 李长荣; 郭翠萍; 杜振民; 李均钦

    2016-01-01

    On the basis of the experimental data of phase equilibria and thermochemical properties available from literatures, a critical assessment for the Ni−Yb binary system was carried out using the CALPHAD (calculation of phase diagrams) method. The liquid phase is modeled as the associate model with the constituent species Ni, Yb and YbNi3, owing to the sharp change of the enthalpy of mixing of liquid phase at the composition of around 25% Yb (mole fraction). The terminal solid solutions FCC_A1 (Ni/Yb) and BCC_A2 (Yb) are described by the substitutional solution model with the Redlich−Kister polynomial. The intermetallic compounds, Yb2Ni17, YbNi5, YbNi3, YbNi2, α-YbNi and β-YbNi, are treated as strict stoichiometric compounds, since there are no noticeable homogeneity ranges reported for these compounds. A set of self-consistent thermodynamic parameters for the Ni−Yb binary system are obtained. According to the presently assessed results, the thermochemical properties and the phase boundary data can be well reproduced.%基于文献报道的相平衡和热化学实验数据,利用相图计算(Calphad)方法对 Ni−Yb 二元系进行热力学评估。考虑到液相混合焓在25% Yb(摩尔分数)附近有急剧变化,液相采用缔合物模型,组份为 Ni、YbNi3和 Yb;端际固溶体相包括 FCC_A1(Ni)、FCC_A1(Yb)和 BCC_A2(Yb),均采用亚规则溶体模型,并按照 Redlich−Kister 多项式进行描述;中间化合物 Yb2Ni17、YbNi5、YbNi3、YbNi2、α-YbNi 和β-YbNi 都没有明显的固溶度实验数据,均按严格计量比处理。优化得到的 Ni−Yb 二元系热力学参数自洽合理,能够很好地再现该体系的热化学性质和相图数据。

  11. Influence of the rare earth concentration on the crystallization process of Fe-Dy-B amorphous alloys. Study of Fe74Dy6B20 and Fe70Dy10B20 alloys

    Science.gov (United States)

    Ravach, G.; Machizaud, F.; Teillet, J.; LeBreton, J. M.; Fnidiki, A.

    2000-04-01

    The crystallization behaviour of Fe74 Dy6 B20 and Fe70 Dy10 B20 amorphous alloys was carefully investigated by differential scanning calorimetry, Mössbauer spectrometry and x-ray diffraction up to 800 °C. Calorimetric studies were performed in limited temperature ranges that were progressively extended. For Fe74 Dy6 B20 , after partial crystallization into the tetragonal Fe3 B compound, the remaining amorphous part segregates into two amorphous `phases', respectively enriched and impoverished in dysprosium. Tetragonal Fe3 B further transforms into orthorhombic Fe3 B. Metastable Dy3 Fe62 B14 compound then forms from the Dy-impoverished amorphous fraction, and subsequent crystallization of the Dy1 + icons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="MIDDLE"/> Fe4 B4 phase occurs in the Dy-enriched fraction. Finally, Dy3 Fe62 B14 decomposes into bcc iron, Dy1 + icons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="MIDDLE"/> Fe4 B4 and iron borides. The nature of the first crystallization product suggests the existence of local environments of t-Fe3 B type for this Dy concentration. The crystallization process of Fe70 Dy10 B20 strongly differs from that of Fe74 Dy6 B20 . Segregation phenomena occur in the amorphous state prior to any crystallization. If the nature of the first crystallization product is assumed to be correlated with short-range order in the amorphous state, our results suggest that the local environments differ from those of Fe74 Dy6 B20 , as they probably involve dysprosium atoms. This behaviour would agree with a previous Mössbauer study performed on the as-quenched amorphous alloys, providing evidence for a structural modification of the iron environments in the rare earth concentration range 8-9 at.%.

  12. Femtosecond pulse generation at 50 W average powers from an Yb:KYW-Yb:YAG planar-waveguide MOPA

    Directory of Open Access Journals (Sweden)

    Baker H. J.

    2013-03-01

    Full Text Available An Yb:YAG planar-waveguide power amplifier seeded by an Yb:KYW master oscillator is reported. The system produced 700-fs pulses at 1032 nm at average output powers of 50 W and a frequency of 53 MHz.

  13. Polytypic phase formation in DyAl3 by rapid solidification

    Science.gov (United States)

    Xu, Yan; Altounian, Z.; Muir, W. B.

    1991-01-01

    Amorphous ribbons of AlxDy100-x, 93≳x≳85, were obtained by melt spinning. During crystallization, in addition to Al, four different metastable crystalline phases of DyAl3 were observed. These phases are, in order of appearance, the high-pressure face-centered cubic phase, γ-DyAl3 and three polytypic rhombohedral phases, β-DyAl3, β'-DyAl3, and α'-DyAl3. It is the first time that the β' phase in rare-earth trialuminides and the α' phase in Dy-Al alloy system have been observed. It is shown that all these phases are associated with the polytypic packing of the hexagonal DyAl3 atomic layers. The relative stability of the phases is found to be related to the hexagonal to cubic stacking ratio in the structure.

  14. Isothermal section of Dy-Zr-Si ternary system at 773 K

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The isothermal section of the phase diagram of the Dy-Zr-Si ternary system at 773 K was determined by X-ray diffraction (XRD) analysis, metallographic analysis, and scanning electron microscopy (SEM) with energy-dispersive spectrometer (EDS) analysis. The isothermal section consists of 13 single-phase regions, 23 two-phase regions, and 11 three-phase regions. The solubilities of Zr in Dy, Dy5Si4, Dy5Si3, DySi, DySi2, DySi1.67, and Dy in Zr, Zr2Si, Zr3Si2, Zr5Si4, ZrSi, and ZrSi2 were determined at 773 K.

  15. Laser spectroscopy and cooling of Yb+ ions on a deep-UV transition

    CERN Document Server

    Meyer, Hendrik M; Ratschbacher, Lothar; Zipkes, Christoph; Köhl, Michael

    2011-01-01

    We perform laser spectroscopy of Yb+ ions on the 4f14 6s 2S_{1/2} - 4f13 5d 6s 3D[3/2]_{1/2} transition at 297 nm. The frequency measurements for 170Yb+, 172Yb+, 174Yb+, and 176Yb+ reveal the specific mass shift as well as the field shifts. In addition, we demonstrate laser cooling of Yb+ ions using this transition and show that light at 297 nm can be used as the second step in the photoionization of neutral Yb atoms.

  16. 75 FR 52534 - Su Van Ho: Debarment Order

    Science.gov (United States)

    2010-08-26

    ... Salmonella bacteria, with verification of such exportation or destruction by FDA. Mr. Ho concealed and... with Salmonella bacteria. As a result of his conviction, on June 10, 2010, FDA sent Mr. Ho a notice...

  17. Conversion of homothallic yeast to heterothallism trough HO gene disruption

    CSIR Research Space (South Africa)

    Van Zyl, WH

    1993-04-01

    Full Text Available A simple method was developed for the conversion of homothallic Saccharomyces cerevisiae yeaststrains to heterothallism through HO gene disruption. An integrative ho:: neo disrupted allele was constructed by cloning a dominant selectable marker...

  18. Spin Waves in Ho2Co17

    DEFF Research Database (Denmark)

    Clausen, Kurt Nørgaard; Lebech, Bente

    1980-01-01

    Spin wave excitations in a single crystal of Ho2Co17 have been studied at 4.8 and 78 K. The results are discussed in terms of a linear spin wave model. At 78 K both ground state and excited state spin waves are observed.......Spin wave excitations in a single crystal of Ho2Co17 have been studied at 4.8 and 78 K. The results are discussed in terms of a linear spin wave model. At 78 K both ground state and excited state spin waves are observed....

  19. Thermodynamic Optimization of DyCl3 -NaCl System

    Institute of Scientific and Technical Information of China (English)

    叶信宇; 孙益民; 张静; 谈君君

    2005-01-01

    In this paper, the phase diagram of the DyCl3 -NaCl system is optimized and calculated with CALPHAD ( calculation of phase diagram ) technology. A set of thermodynamic functions of compounds Na3 DyCl6, NaDyCl4, and NaDY2 Cl7 have been optimized and calculated based on an interactive computer-assisted analysis. The optimized thermodynamic parameters, calculated phase diagram and experimental phase diagram are thermodynamically serf-consistent.

  20. Investigations of the effect of nonmagnetic Ca substitution for magnetic Dy on spin-freezing in Dy2Ti2O7

    Science.gov (United States)

    Anand, V. K.; Tennant, D. A.; Lake, B.

    2015-11-01

    Physical properties of partially Ca substituted hole-doped Dy2Ti2O7 have been investigated by ac magnetic susceptibility {χ\\text{ac}}(T) , dc magnetic susceptibility χ (T) , isothermal magnetization M(H) and heat capacity {{C}\\text{p}}(T) measurements on Dy1.8Ca0.2Ti2O7. The spin-ice system Dy2Ti2O7 exhibits a spin-glass type freezing behavior near 16 K. Our frequency dependent {χ\\text{ac}}(T) data of Dy1.8Ca0.2Ti2O7 show that the spin-freezing behavior is significantly influenced by Ca substitution. The effect of partial nonmagnetic Ca2+ substitution for magnetic Dy3+ is similar to the previous study on nonmagnetic isovalent Y3+ substituted Dy2-x Y x Ti2O7 (for low levels of dilution), however the suppression of spin-freezing behavior is substantially stronger for Ca than Y. The Cole-Cole plot analysis reveals semicircular character and a single relaxation mode in Dy1.8Ca0.2Ti2O7 as for Dy2Ti2O7. No noticeable change in the insulating behavior of Dy2Ti2O7 results from the holes produced by 10% Ca2+ substitution for Dy3+ ions.

  1. The crucial role of Mn spiral spin order in stabilizing the Dy-Mn exchange striction in multiferroic DyMnO3.

    Science.gov (United States)

    Wang, H W; Li, C L; Yuan, S L; Wang, J F; Lu, C L; Liu, J-M

    2017-02-01

    DyMnO3 hosts the less addressed duality of multiferroicity, owing to the Dy-Mn exchange striction and inverse Dzyaloshinskii-Moriya interaction between Mn spin pairs. Although the duality in DyMnO3 has been discussed earlier, there remains a question whether the Mn magnetic sublattice is necessarily multiferroic for generating the Dy-Mn exchange striction. In this work, we investigate the multiferroicity of Dy(Mn1-xFex)O3 (0 ≤ x ≤ 0.1) through detailed magnetic and ferroelectric characterization. It is found that Fe-doping continuously suppresses the independent Dy spin order but instead promotes the Dy-Mn(Fe) coupling. This coupling benefits the Dy-Mn(Fe) exchange striction which remarkably enhances the ferroelectric polarization at a low doping level (x ≤ 0.015), beyond which the Mn spiral spin order breaks down leading to collapse of the macroscopic polarization at x ≥ 0.05. This work discloses the crucial role of Mn spiral spin order in stabilizing the Dy-Mn exchange striction and thus highlights the duality of multiferroicity in DyMnO3.

  2. Tetranuclear {Co(II)2Co(III)2}, Octanuclear {Co(II)4Co(III)4}, and Hexanuclear {Co(III)3Dy(III)3} Pivalate Clusters: Synthesis, Magnetic Characterization, and Theoretical Modeling.

    Science.gov (United States)

    Radu, Ioana; Kravtsov, Victor Ch; Ostrovsky, Serghei M; Reu, Oleg S; Krämer, Karl; Decurtins, Silvio; Liu, Shi-Xia; Klokishner, Sophia I; Baca, Svetlana G

    2017-03-06

    New tetranuclear and octanuclear mixed-valent cobalt(II/III) pivalate clusters, namely, [NaCo4(O2CCMe3)6(HO2CCMe3)2(teaH)2(N3)]·2H2O (in two polymorphic modifications, 1 and 1a) and [Co8(O2CCMe3)10(teaH)4(N3)](Me3CCO2)·MeCN·H2O (2) have been synthesized by ultrasonic treatment of a dinuclear cobalt(II) pivalate precursor with sodium azide and triethanolamine (teaH3) ligand in acetonitrile. The use of Dy(NO3)3·6H2O in a similar reaction led to the precipitation of a tetranuclear [NaCo4(O2CCMe3)4(teaH)2(N3)(NO3)2(H2O)2]·H2O (3) cluster and a heterometallic hexanuclear [Co3Dy3(OH)4(O2CCMe3)6(teaH)3(H2O)3](NO3)2·H2O (4) cluster. Single-crystal X-ray analysis showed that 1 (1a) and 3 consist of a tetranuclear pivalate/teaH3 mixed-ligand cluster [Co(II)2Co(III)2(O2CCMe3)4(teaH)2(N3)](+) decorated with sodium pivalates [Na(O2CCMe3)2(HO2CCMe3)2](-) (1 or 1a) or sodium nitrates [Na(NO3)2](-) (3) to form a square-pyramidal assembly. In 2, the cationic [Co8(O2CCMe3)10(teaH)4(N3)](+) cluster comprises a mixed-valent {Co(II)4Co(III)4} core encapsulated by an azide, 4 teaH(2-) alcoholamine ligands, and 10 bridging pivalates. Remarkably, in this core, the μ4-N3(-) ligand joins all four Co(II) atoms. The heterometallic hexanuclear compound 4 consists of a cationic [Co(III)3Dy(III)3(OH)4(O2CCMe3)6(teaH)3(H2O)3](2+) cluster, two NO3(-) anions, and a crystallization water molecule. The arrangement of metal atoms in 4 can be approximated as the assembly of a smaller equilateral triangle defined by three Dy sites with a Dy···Dy distance of 3.9 Å and a larger triangle formed by Co sites [Co···Co, 6.1-6.2 Å]. The interpretation of the magnetic properties of clusters 2-4 was performed in the framework of theoretical models, taking into account the structural peculiarities of clusters and their energy spectra. The behavior of clusters 2 and 3 containing Co(II) ions with orbitally nondegenerate ground states is determined by the zero-field splitting of these states and

  3. Switching the conductance of Dy nanocontacts by magnetostriction.

    Science.gov (United States)

    Müller, Marc; Montbrun, Richard; Marz, Michael; Fritsch, Veronika; Sürgers, Christoph; v Löhneysen, Hilbert

    2011-02-09

    The electrical conductance G of mechanical break-junctions fabricated from the rare-earth metal dysprosium has been investigated at 4.2 K where Dy is in the ferromagnetic state. In addition to the usual variation of the conductance while breaking the wire mechanically, the conductance can be changed reproducibly by variation of the magnetic field H, due to the large magnetostriction of Dy. For a number of contacts, we observe discrete changes in G(H) in the range of several G(0) = 2e(2)/h. The behavior of G(H) and its angular dependence can be quantitatively understood by taking into account the magnetostrictive properties of Dy. This realization of a magnetostrictive few-atom switch demonstrates the possibility of reproducibly tuning the conductance of magnetic nanocontacts by a magnetic field.

  4. Optogalvanic Spectroscopy of Metastable States in Yb^{+}

    CERN Document Server

    Petrasiunas, M J; Weinhold, T J; Norton, B G; Kielpinski, D

    2011-01-01

    The metastable ^{2}F_{7/2} and ^{2}D_{3/2} states of Yb^{+} are of interest for applications in metrology and quantum information and also act as dark states in laser cooling. These metastable states are commonly repumped to the ground state via the 638.6 nm ^{2}F_{7/2} -- ^{1}D[5/2]_{5/2} and 935.2 nm ^{2}D_{3/2} -- ^{3}D[3/2]_{1/2} transitions. We have performed optogalvanic spectroscopy of these transitions in Yb^{+} ions generated in a discharge. We measure the pressure broadening coefficient for the 638.6 nm transition to be 70 \\pm 10 MHz mbar^{-1}. We place an upper bound of 375 MHz/nucleon on the 638.6 nm isotope splitting and show that our observations are consistent with theory for the hyperfine splitting. Our measurements of the 935.2 nm transition extend those made by Sugiyama et al, showing well-resolved isotope and hyperfine splitting. We obtain high signal to noise, sufficient for laser stabilisation applications.

  5. Optical properties of Yb ions in GaN epilayer

    Science.gov (United States)

    Jadwisienczak, W. M.; Lozykowski, H. J.

    2003-07-01

    In recent years, an important effort in semiconductor materials research has been devoted to III-nitrides semiconductors doped with rare earth ions due to the high potential of these materials in light-emitting device applications. Ytterbium (Yb 3+) is one of a few lanthanide ions which have not been investigated as an optically active center in these materials yet. In this paper we report the observation of luminescence from GaN films grown on sapphire (0 0 0 1) substrate by metal organic chemical vapor deposition and doped by implantation with Yb 3+ ions. The high resolution photo- and cathodoluminescence spectra of GaN:Yb 3+ were studied at different excitation conditions in temperatures ranging from 8 to 330 K and revealed weak thermal quenching. The luminescence emission lines are assigned to transitions between the spin-orbit levels 2F 5/2 → 2F 7/2 of Yb 3+ (4f 13). The analysis of the Yb luminescence spectra allowed us to suggest the energy level diagram of the crystal-field-split 4f 13 levels for the Yb ion center. The most probable lattice location of Yb in GaN is the substitutional Ga site. Furthermore, the luminescence kinetics of internal transitions of Yb 3+ incorporated in GaN was investigated by means of decay and time-resolved luminescence measurements. It was found that the ytterbium decay is non-exponential with dominant exponential term of ˜100 μs with little dependence on the ambient temperature. The results indicate that Yb-doped GaN epilayer may be suitable as a material for near infrared optoelectronic devices.

  6. Low temperature magnetic properties of DyPdBi

    Science.gov (United States)

    Mukhopadhyay, A.; Chowki, S.; Mohapatra, N.

    2016-05-01

    We report the results of dc magnetization measurements in the ternary half -Heuslar alloy, DyPdBi which crystallizes in a non centrosymmetric MgAgAs type fcc structure. DyPdBi undergoes a long range antiferromagnetic type ordering below 4.0 K as inferred from the temperature dependence of dc magnetic susceptibility. Another noteworthy observation is the field induced metamagnetic transition below TN, further suggestes that the order-order field induced transition as a first order phase transition.

  7. Optical studies of Dy-doped Bi-2212.

    Science.gov (United States)

    Gasparov, L.; Pekarek, T.; Tanner, D.; Berger, H.; Forro, L.; Margaritondo, G.

    2001-03-01

    We present temperature-dependent reflectance measurements for Dy doped Bi-2212 based single crystals with T_c=3D 55 and 70K in the frequency range from 100 to 40,000 cm-1 (0.012--5 eV). The material is interesting on account of a weak ferromagnetic-type magnetization behavior. The optical conductivity is obtained by Kramers-Kronig analysis. We compare Dy-doped crystals with other previously measured Bi-2212 based crystals by analyzing optical conductivity in the framework of a two-fluid approach. This approach allows us to follow correlations between superfluid density and superconducting transition temperature of the materials. =00

  8. Thermoluminescent characteristics of nano-structure hydroxyapatite:Dy

    Energy Technology Data Exchange (ETDEWEB)

    Ziaie, F. [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School; Moein, N. Farhadi [Islamic Azad Univ. (Iran, Islamic Republic of). Central Tehran Branch; Shafaei, M. [Islamic Azad Univ. (Iran, Islamic Republic of). Science and Research Branch

    2014-12-15

    The thermoluminescence response of Dysprosium doped hydroxyapatite samples with different mol percentage of 0.5, 1 and 2 were studied and compared with the pure hydroxyapatite. The samples were objected to {sup 60}Co gamma rays irradiation with doses of 100 mGy to 10 Gy. The main peak in the sample glow curves were obtained at 310 C. The sensitivity of the 1 mol% Dy doped hydroxyapatite samples show the highest thermoluminescence response. Fading behavior of the irradiated samples was also studied. The experimental results show that the synthetic Dy-doped hydroxyapatite obtained by the hydrolysis method may be used in gamma radiation dosimetry.

  9. Optical properties of lead borate glasses containing Dy3+ ions

    Science.gov (United States)

    Pisarska, Joanna

    2009-07-01

    Optical properties of lead borate glasses containing Dy3+ ions were examined using absorption and luminescence measurements and theoretical calculations based on the Judd-Ofelt framework and the Inokuti-Hirayama model. The luminescence spectra show two characteristic bands at 480 and 573 nm, which are due to 4F9/2-6H15/2 (blue) and 4F9/2-6H13/2 (yellow) transitions of trivalent Dy3+ ions. The yellow/blue luminescence and its decay were analyzed as a function of activator concentration.

  10. Defective muscle basement membrane and lack of M-laminin in the dystrophic dy/dy mouse

    DEFF Research Database (Denmark)

    Xu, H; Christmas, P; Wu, X R;

    1994-01-01

    M-laminin is a major member of the laminin family of basement membrane proteins. It is prominently expressed in striated muscle and peripheral nerve. M-laminin is deficient in patients with the autosomal recessive Fukuyama congenital muscular dystrophy but is normal in patients with the sex......-linked Duchenne and Becker muscular dystrophies. We have examined M-laminin expression in mice with autosomal recessive muscular dystrophy caused by the mutation dy. The heavy chain of M-laminin was undetectable in skeletal muscle, heart muscle, and peripheral nerve by immunofluorescence and immunoblotting...... in homozygous dystrophic dy/dy mice but was normal in heterozygous and wild-type nondystrophic mice. Immunofluorescence confirmed the presence of other major basement membrane proteins in the dystrophic mice. Very low levels of M-laminin heavy chain mRNA were detected by Northern blotting of muscle and heart...

  11. Magnetic and Electronic Properties of R3Ni7B2 Compounds where R = Dy, Ho, Er

    Science.gov (United States)

    Bucur, N.; Vlaic, P.; Burzo, E.

    2007-04-01

    Band structure calculations show the presence of small magnetic moments at Ni sites. Magnetic measurements at 4.2 K evidenced a relative high anisotropy. Magnetic behavior of nickel is analyzed in spin fluctuation model.

  12. Variations of magnetocaloric effect and magnetoresistance across RCuGe (R=Tb, Dy, Ho, Er) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Sachin; Suresh, K.G., E-mail: suresh@phy.iitb.ac.in

    2015-10-01

    RCuGe (R=Tb–Er) compounds have been studied by structural, magnetic, magnetocaloric and magnetotransport measurements. All these compounds are iso-structural and show antiferromagnetic ordering below their Néel temperatures (T{sub N}). Except TbCuGe, all the studied compounds show large magnetocaloric effect (MCE), arising due to the field induced metamagnetic transition. They also show a sign reversal of magnetoresistance (MR) with change in temperature or field. The non-monotonic variation of the magnitude of MR is attributed to the competing effects of Lorentz force, changes in the spin disorder scattering and the spin fluctuations. - Highlights: • RCuGe (R=Tb–Er) compounds show low temperature antiferromagnetic ordering. • All compounds show field induced metamagnetic transitions. • These compounds show large magnetocaloric effect and magnetoresistance.

  13. Magnetoresistance, susceptibility and magnetization measurements on RNiBC compounds (R = Er, Ho, Dy, Tb, and Gd)

    Science.gov (United States)

    Tróchez, J. C.; Sánchez, D. R.; Giordanengo, B.; Fontes, M. B.; Continentino, Múcio; Baggio-Saitovitch, E. M.

    1997-08-01

    We studied magnetic behavior of the RNiBC compounds by magnetic and transport measurements. At low temperatures, each compound has different magnetic structure. Magnetoresistivity data are in good accordance with theory of magnetic elementary interactions, susceptibility reveals the magnetic transition and Curie Weiss behavior and magnetization shows low value of the saturation compared with the free R+3 ion that confirm that crystalline electric field is strong as in the RNi2B2C series.

  14. X-ray resonant magnetic scattering investigations of hexagonal multiferroics RMnO3 (R = Dy, Ho, Er)

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, Shibabrata [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Electricity and magnetism were unified into a common subject by James Clerk Maxwell in the nineteenth century yielding the electromagnetic theory. Four equations govern the dynamics of electric charges and magnetic fields, commonly known as Maxwell's equations. Maxwell's equations demonstrate that an accelerated charged particle can produce magnetic fields and a time varying magnetic field can induce a voltage - thereby linking the two phenomena. However, in solids, electric and magnetic ordering are most often considered separately and usually with good reason: the electric charges of electrons and ions are responsible for the charge effects, whereas the electron spin governs magnetic properties.

  15. Rekonstrukce historického vozidla

    OpenAIRE

    Richter, Tomáš

    2010-01-01

    Cílem této bakalářské práce je navrhnout postup rekonstrukce historického vozidla a dokumentovat jednotlivé etapy. This bachelor’s thesis offers process of redesign veteran motor car and documents particular stages. A

  16. Saigon-Ho Chi Minh City

    NARCIS (Netherlands)

    Nguyen, T.B.; Samsura, D.A.A.; Krabben, E. van der; Le, A.-D.

    2016-01-01

    Ho Chi Minh City (HCMC) has existed for over three centuries and has developed into the financial capital and most important economic hub of Vietnam. This profile outlines the history of HCMC's development and its impact on current conditions and physical structure of the city. The paper analyzes so

  17. Luminescence investigation of Dy2O2S and Dy2O2SO4 obtained by thermal decomposition of sulfate hydrate

    Institute of Scientific and Technical Information of China (English)

    RV Rodrigues; L Marciniak; LU Khan; JR Matos; HF Brito; W Strk

    2016-01-01

    The yellow emitting dysprosium oxysulfide (Dy2O2S) and dysprosium oxysulfate (Dy2O2SO4) compounds were prepared from the thermal decomposition of hydrated dysprosium sulphate. The materials were characterized by using thermogravimetry (TG/DTG), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopies. The thermal stability temperatures at around 1151 and 1313 K were determined for the Dy2O2S and Dy2O2SO4 materials, respectively. The photolumines-cence properties of the dysprosium oxysulfide were investigated, showing narrow emission bands assigned to the 4F9/2→6HJ intracon-figurational transitions of the Dy3+ion. The yellow emission color of this phosphor suggests that the Dy2O2S is a promising material for applications in LEDs.

  18. Sympathetic cooling of 171 Yb+ qubit ions on a scalable ion trap chip using Yb isotopes

    Science.gov (United States)

    Kwon, Yeong-Dae; Ahn, Jun Sik; Hong, Seokjun; Lee, Minjae; Cheon, Hongjin; Cho, Dongil ``Dan''; Kim, Taehyun

    2016-05-01

    To achieve ion trap based large-scale quantum computing devices, motional states of qubit ions must be regulated against heating from ion transportation or noise on the chip surface while leaving internal states of the ions intact. Sympathetic cooling is a natural solution for this problem, but trapping two different species of ions generally requires two sets of optical devices including separate lasers for each ion type, increasing the complexity and the cost of the setup. We tested Doppler-cooled 174 Yb+ ions to sympathetically cool 171 Yb+ qubit ions. Since these two isotopes have energy levels close to each other, the optical setup can be vastly simplified. We also verified that the tail of non-ideally focused cooling beam and the scattered light from the surface create excited state population in the 171 Yb+ qubit ions, as expected. This leads to occasional spontaneous emission events, which currently limits the coherence time of our qubit to a few seconds. We will also discuss our plans for optimizing the experiment, which may increase the coherence time by one or two orders of magnitude. This work was partially supported by ICT R&D program of MSIP/IITP. [10043464, Development of quantum repeater technology for the application to communication systems].

  19. Electrochemical performance of alloys Ho_5Fe_3Co_(12) and Ho_(33.3)Co_(66.7)

    Institute of Scientific and Technical Information of China (English)

    赵允红; 何维; 张永志; 曾令民

    2010-01-01

    Alloys with composition Ho5Fe3Co12 and Ho33.3Co66.7 were prepared and examined by X-ray diffractometer and automatic battery testing instrument. The electrochemical properties of these alloys such as discharge capacity, cycling performance and high rate dischargeability were investigated by battery testing instruments in alkaline electrolyte. A comparison of the electrochemical performance of the Ho5Fe3Co12 and Ho33.3Co66.7 alloys revealed that alloy Ho5Fe3Co12 possessed a better electrochemical performance...

  20. Isotope separation of the Yb-168 stable isotope for low energy gamma ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyun Min; Kwon, Duck Hee; Cha, Yong Ho; Lee, Ki Tae; Nam, Sung Mo; Yoo, Jaek Won; Han, Jae Min; Rhee, Yong Joo [Lab. of Quantum Optics, Korea Atomic Energy Research Institute, Taejeon (Korea, Republic of)

    2003-07-01

    We developed laser isotope separation technology of stable isotope of low melting point metals. Yb-168 can be effectively used in non-destructive testing (NDT) after it is transformed to Yb-168 by neutron irradiation in a nuclear reactor. For this application of Yb-168, the isotope purity of it should be enhanced to more than 15% from the natural abundance of 0.135%. Our isotope separation system consist of laser system, Yb vapor generating system, and photoionized particle extraction system. For the system, we developed a diode-pumped slid-state laser of high-repetition rate and 3-color dye lasers. Yb vapor was generated by heating solid Yb sample resistively. The photo-ion produced by resonance ionization were extracted by a devised extractor. We produced enriched Yb metal more than 20 mg with the abundance of 25.8% of Yb-168 in the Yb (NO{sub 3}){sub 3}.

  1. Influence of Dy content on the structure and giant magnetoresistance of Dy x(Co 40Ag 60) 100- x granular films

    Science.gov (United States)

    Gang, Cheng; Xiaofei, Wu; Wei, Chen; Shengdong, Geng; Lin, Li; Zhengfei, Gu

    2012-01-01

    Dyx(Co40Ag60)100-x (x = 0, 0.7, 1.4, 2.1, 2.8, 3.5) granular films have been prepared by DC magneto controlled sputtering method. The XRD data indicated that Dy element restrained the (1 1 1) plane preferential orientation. Magnetic measurements indicated that the average size of magnetic particles increased with the increasing in Dy content. For relatively low addition Dy to CoAg granular films, Dy element can enhance GMR value as a maximum value of the GMR value ∼-18.1% at x = 0.7.

  2. Optical properties of epitaxial YAG:Yb films

    Science.gov (United States)

    Ubizskii, S. B.; Matkovskii, A. O.; Melnyk, S. S.; Syvorotka, I. M.; Müller, V.; Peters, V.; Petermann, K.; Beyertt, A.; Giesen, A.

    2004-03-01

    This work deals with the investigation of the optical properties of epitaxial YAG:Yb films and their suitability as gain media for thin disk lasers. Epitaxial films of YAG:Yb were grown by the liquid phase epitaxy method in air on the (111)-oriented YAG substrates. The thickness of the grown layers was from 30 to 260 m. The melt composition was varied to obtain the desired doping level from 10 to 15% and to optimize the optical properties. The best epitaxial films were colourless and had an Yb3+ luminescence lifetime of more than 950 s, which is very close to the intrinsic lifetime of the Yb ions in the bulk YAG single crystals. These films were tested in a thin disk laser setup with 24 absorption passes of the 940 nm pumping beam. The maximum output power at 1.03 m wavelength in CW operation reached more than 60 W and the optical efficiency was close to 30%.

  3. Studies of normal deformation in {sup 151}Dy

    Energy Technology Data Exchange (ETDEWEB)

    Nisius, D.; Janssens, R.V.F.; Crowell, B. [and others

    1995-08-01

    The wealth of data collected in the study of superdeformation in {sup 151}Dy allowed for new information to be obtained on the normally deformed structures in this nucleus. At high spin several new yrast states have been identified for the first time. They were associated with single-particle excitations. Surprisingly, a sequence was identified with energy spacings characteristic of a rotational band of normal ({beta}2 {approximately} 0.2) deformation. The bandhead spin appears to be 15/2{sup -} and the levels extend up to a spin of 87/2{sup -}. A clear backbend is present at intermediate spins. While a similar band based on a bandhead of 6{sup +} is known in {sup 152}Dy, calculations suggest that this collective prolate band should not be seen in {sup 151}Dy. In the experiment described earlier in this report that is aimed at determining the deformations associated with the SD bands in this nucleus and {sup 152}Dy, the deformation associated with this band will be determined. This will provide further insight into the origin of this band.

  4. Magnetoelastic vibration damping properties of TbDy alloys

    Science.gov (United States)

    Dooley, Jennifer A.; Good, Nathan R.; White, Christopher V.; Leland, Robert S.

    2003-03-01

    Damping of axial and bending mode vibrations in giant magnetoelastic polycrystalline TbDy alloys was studied at cryogenic temperatures. All specimens of TbDy were arc-melted in the proper composition ratio and dropped into a chilled copper mold. Additional treatments consisted of cold plane-rolling to induce crystallographic texture and then heat-treating to relieve internal stress. Mechanical hysteretic losses were measured at various strains, frequencies, and loading configurations down to 77 K. Both as-cast and textured polycrystalline TbDy samples were tested along with an aluminum specimen for comparison. Loss factors at multiple natural vibration frequencies of the samples were measured for axial modes. Larger damping rates were measured for axial mode vibrations than for bending mode vibrations, possibly reflecting the larger specimen volume contributing to magnetoelastic damping. At LN2 temperatures TbDy materials demonstrated η > 0.05 at 0.01 Hz and η > 0.1 at higher frequencies from 0.6-1.5 kHz.

  5. EST Table: DY231350 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available DY231350 EST02101 10/09/28 99 %/227 aa ref|NP_001037309.1| vitellogenin precursor [...s: Precursor dbj|BAA02444.1| vitellogenin precursor [Bombyx mori] dbj|BAA06397.1| vitellogenin [Bombyx mori

  6. Using polyvinyl chloride dyed with bromocresol purple in radiation dosimetry.

    Science.gov (United States)

    Kattan, Munzer; al Kassiri, Haroun; Daher, Yarob

    2011-02-01

    Polyvinyl chloride (PVC) dyed with bromocresol purple was investigated as a high-dose radiation dosimeter. The absorbance at 417 nm depends linearly on the dose below 50 kGy. The response depends neither on dose rate nor on the irradiation temperature. The effects of post-irradiation storage in the dark and in indirect sunlight are also discussed.

  7. Surface activation of dyed fabric for cellulase treatment.

    Science.gov (United States)

    Schimper, Christian B; Ibanescu, Constanta; Bechtold, Thomas

    2011-10-01

    Surface activation of fabric made from cellulose fibres, such as viscose, lyocell, modal fibres and cotton, can be achieved by printing of a concentrated NaOH-containing paste. From the concentration of reducing sugars formed in solution, an increase in intensity of the cellulase hydrolysis by a factor of six to eight was observed, which was mainly concentrated at the activated parts of the fabric surface. This method of local activation is of particular interest for modification of materials that have been dyed with special processes to attain an uneven distribution of dyestuff within the yarn cross-section, e.g., indigo ring-dyed denim yarn for jeans production. Fabrics made from regenerated cellulose fibres were used as model substrate to express the effects of surface activation on indigo-dyed material. Wash-down experiments on indigo-dyed denim demonstrated significant colour removal from the activated surface at low overall weight loss of 4-5%. The method is of relevance for a more eco-friendly processing of jeans in the garment industry.

  8. Determination of two reactive dyes concentration in dyed cotton fabric

    Directory of Open Access Journals (Sweden)

    Miljković Milena

    2012-01-01

    Full Text Available The purpose of this paper was to determine the unknown concentration of dichlortriazinyl reactive dyes, namely Reactive Yellow 22 and Reactive Blue 163, in dyed cotton fabric. The samples of cotton fabric were dyed individually with each dye as well as with a mixture of two dyes. The unknown concentrations of dyes were determined by measuring the corresponding reflectance values of dyed fabric samples and then using the relation between the concentration and reflectance values of the samples. The method set by Kubelka and Munk was used. The accuracy and repeatability of the concentrations determination were calculated by the statistical processing of the data obtained by measurements. Relative errors of individual determination of Reactive Yellow 22 and Reactive Blue 163 were 3.66% and 5.94% respectively. Relative errors in determination of Reactive Yellow 22 and Reactive Blue 163 in a mixture were 3.47% and 3.19% respectively. The results showed that reflectance spectrophotometry can be successfully used as the method for concentration determination of Reactive Yellow 22 and Reactive Blue 163 in dyed cotton fabric and can therefore be applied as the shade control method in dyeing.

  9. EST Table: DY230716 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available DY230716 EST01452 10/09/28 51 %/110 aa ref|XP_002427369.1| Integrator complex subun...it, putative [Pediculus humanus corporis] gb|EEB14631.1| Integrator complex subunit, putative [Pediculus hum

  10. EST Table: DY230676 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available x mori] dbj|BAA89306.1| Promoting Protein [Bombyx mori] 10/09/03 32 %/105 aa FBpp0237404|DvirGJ22987-PA 10/0...DY230676 EST01412 10/09/28 87 %/127 aa ref|NP_001036842.1| promoting protein [Bomby

  11. EST Table: DY231371 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available DY231371 EST02122 10/09/28 98 %/130 aa ref|NP_001040121.1| endothelial-monocyte act...ivating polypeptide II [Bombyx mori] gb|ABD36113.1| endothelial-monocyte activating polypeptide II [Bombyx m

  12. Viscosity, fission time scale and deformation of Dy-156

    NARCIS (Netherlands)

    van't Hof, G; Bacelar, JCS; Dioszegi, [No Value; Harakeh, MN; Hesselink, WHA; Kalantar-Nayestanaki, N; Kugler, A; van der Ploeg, H; Plompen, AJM; van Schagen, JPS

    1998-01-01

    In the fusion-fission reaction Ar-40 + Cd-116 --> Dy-156*, fission, at E-b = 216 MeV and 238 MeV, gamma-rays were measured in coincidence with fission fragments. The interpretation of the gamma-ray spectra is done with the help of a modified version of the statistical-model code CASCADE. The spectra

  13. Redetermination of Dy3Ni from single-crystal X-ray data

    Science.gov (United States)

    Levytskyy, Volodymyr; Babizhetskyy, Volodymyr; Kotur, Bohdan; Smetana, Volodymyr

    2013-01-01

    The classification of the title compound, tridysprosium nickel, into the Fe3C (or Al3Ni) structure type has been deduced from powder X-ray diffraction data with lattice parameters reported in a previous study [Lemaire & Paccard (1967 ▶). Bull. Soc. Fr. Mineral. Cristallogr. 40, 311–315]. The current re-investigation of Dy3Ni based on single-crystal X-ray data revealed atomic positional parameters and anisotropic displacement parameters with high precision. The asymmetric unit consists of two Dy and one Ni atoms. One Dy atom has site symmetry .m. (Wyckoff position 4c) and is surrounded by twelve Dy and three Ni atoms. The other Dy atom (site symmetry 1, 8d) has eleven Dy and three Ni atoms as neighbours, forming a distorted Frank–Kasper polyhedron. The coordination polyhedron of the Ni atom (.m., 4c) is a tricapped trigonal prism formed by nine Dy atoms. PMID:24454015

  14. Redetermination of Dy3Ni from single-crystal X-ray data

    Directory of Open Access Journals (Sweden)

    Volodymyr Levytskyy

    2013-11-01

    Full Text Available The classification of the title compound, tridysprosium nickel, into the Fe3C (or Al3Ni structure type has been deduced from powder X-ray diffraction data with lattice parameters reported in a previous study [Lemaire & Paccard (1967. Bull. Soc. Fr. Mineral. Cristallogr. 40, 311–315]. The current re-investigation of Dy3Ni based on single-crystal X-ray data revealed atomic positional parameters and anisotropic displacement parameters with high precision. The asymmetric unit consists of two Dy and one Ni atoms. One Dy atom has site symmetry .m. (Wyckoff position 4c and is surrounded by twelve Dy and three Ni atoms. The other Dy atom (site symmetry 1, 8d has eleven Dy and three Ni atoms as neighbours, forming a distorted Frank–Kasper polyhedron. The coordination polyhedron of the Ni atom (.m., 4c is a tricapped trigonal prism formed by nine Dy atoms.

  15. Preparation and Characterization of Yb - doped YAG Ceramics

    OpenAIRE

    2011-01-01

    Rare-earth doped yttrium aluminum garnet (YAG) ceramics are among the most widely produced transparent ceramics for laser applications. Yb:YAG ceramics are an interesting IR laser material [1], which allows significantly higher doping compared to the generally more used Nd:YAG [2,3]. This work presents the preparation of polycrystalline Yb:YAG ceramics with dopant concentration from 0 up to 20 at.% via solid state reactive sintering. Samples were prepared via cold isostatic pressing of spray ...

  16. Polarizing 50micrometers Core Yb-Doped Photonic Bandgap Fiber

    Science.gov (United States)

    2015-02-08

    properly. Recent reports demonstrate that the birefringence in photonic bandgap fibers (PBFs) can provide single-polarization operation by shifting the...add ref]. Here, we demonstrate a 50µm core Yb-doped polarizing photonic bandgap fiber (PBF) for single-polarization operation 1. REPORT DATE (DD-MM...19-08-2015 Approved for public release; distribution is unlimited. Polarizing 50µm core Yb-doped photonic bandgap fiber The views, opinions and/or

  17. [Direct upconversion sensitization luminescence comparison of the ErYb co-doped oxyfluoride fluoride pentaphosphate glass].

    Science.gov (United States)

    Chen, Xiao-bo; Chen, Luan; Zhao, Chen-yi; Sawanobori, N; Ma, Hui; Song, Zeng-fu

    2003-02-01

    This paper investigates the direct upconversion sensitization luminescence of the ErYb co-doped oxyfluoride glass (ErYb: FOG), fluoride glass (ErYb: ZBLAN) and pentaphosphate noncrystalline (ErYb: PP) excited by a 966 nm diode laser. The splendid upconversion luminescence phenomenon is found. It is resulted from that the Yb3+ concentration in rather high, the energy transfer among Er(3+)-Yb3+ and Yb(3+)-Yb3+ ions is rather strong. An important fact is found that the direct upconversion sensitization luminescence of ErYb: FOG is about 100-100,000 times greater than that of ErYb: PP. And meanwhile it is interesting that the upconversion luminescence intensity of ErYb: FOG is near to that of ErYb: ZBLAN. It is significant to enhance the comprehensive level of up-conversion luminescence.

  18. Lifetimes of high-spin states in {sup 162}Yb

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M.P.; Janssens, R.V.F.; Henry, R.G. [and others

    1995-08-01

    A measurement on lifetimes of high-spin states in the yrast and near-yrast rotational bands in {sup 162}Yb was carried out at ATLAS in order to determine the evolution of collectivity as a function of angular momentum using the {sup 126}Te({sup 40}Ar,4n){sup 162}Yb reaction at 170 MeV. Previous lifetime measurements in the {sup 164,166,168}Yb isotopes showed a dramatic decrease in the transition quadrupole moment Q{sub t} with increasing spin. It was suggested that this decrease in Q{sub t} is brought about by the rotationally-induced deoccupation of high-j configurations, mainly i{sub 13/2} neutrons. If this interpretation is correct, the heavier isotopes should have a larger decrease in Q{sub t} than the lighter mass nuclides due to the position of the Fermi surface in the i{sub 13/2} subshell. Indeed, {sup 160}Yb does not show a clear decrease in Q{sub t} at high spin. No high spin lifetime information exists for {sup 162}Yb, thus this experiment fills the gap of measured Q{sub t}`s in the light Yb series. The data is currently being analyzed.

  19. Scattering lengths in isotopologues of the RbYb system

    CERN Document Server

    Borkowski, Mateusz; Ciuryło, Roman; Julienne, Paul S; K{\\ke}dziera, Dariusz; Mentel, Łukasz; Tecmer, Paweł; Münchow, Frank; Bruni, Christian; Görlitz, Axel

    2013-01-01

    We model the binding energies of rovibrational levels of the RbYb molecule using experimental data from two-color photoassociation spectroscopy in mixtures of ultracold $^{87}$Rb with various Yb isotopes. The model uses a theoretical potential based on state-of-the-art \\emph{ab initio} potentials, further improved by least-squares fitting to the experimental data. We have fixed the number of bound states supported by the potential curve, so that the model is mass scaled, that is, it accurately describes the bound state energies for all measured isotopic combinations. Such a model enables an accurate prediction of the s-wave scattering lengths of all isotopic combinations of the RbYb system. The reduced mass range is broad enough to cover the full scattering lengths range from $-\\infty$ to $+\\infty$. For example, the $^{87}$Rb$^{174}$Yb system is characterized by a large positive scattering length of $+880(120)$~a.u., while $^{87}$Rb$^{173}$Yb has $a=-626(88)$~a.u.. On the other hand $^{87}$Rb$^{170}$Yb has a ...

  20. Preparation and Characterization of Downconversion Luminescent LaVO4: Tm3+ , Yb3+ and Tm3+ /Yb3+ Nanosheets

    Directory of Open Access Journals (Sweden)

    M. Zahedifar

    2012-03-01

    Full Text Available Tm3+ , Yb3+  and Tm3+ /Yb3+  doped LaVO4 nanostructures were synthe- sized for the first time by using the hydrothermal method with the aid of La(CH3CO23 as  lanthanum source in presence of oleic acid as surfactant. The products were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, photoluminescence (PL spectroscopy and UV– Vis diffuse reflectance spectroscopy. Besides, the effects of activator concentration and sensitizer on the emission intensity were investi- gated. The PL spectrum revealed that the emission intensity decreases with increase in the concentration of Tm3+ , while adding Yb3+ as sensi- tizer causes the emission intensity to increase. The LaVO4: Tm3+ /Yb3+   may possibly have potential application in enhancing the conversion efficiency of dye-sensitized solar cells by increasing the absorption of dyes.

  1. Studies on fractionation of ytterbium isotopes in Yb(III)-acetate/Yb-amalgam system. Even-odd effect

    Energy Technology Data Exchange (ETDEWEB)

    Dembinski, W.; Poninski, M.; Fiedler, R.

    1997-12-31

    The fractionation of ytterbium isotopes with the even and odd numbers of neutrons was investigated in a Yb(III)-acetate/Yb-amalgam exchange systems. The light isotope was preferentially fractionated to the amalgam phase. The values of the unit separation gain per mass difference,{epsilon}, were found to be -0.00054 for {sup 176/171}Yb and -0.00069 for {sup 176/174}Yb The difference which amounted to 0.00015 is an evidence for the occurrence of the so called `even-odd` effect. It was also found that the chemical isotope shift of ytterbium was monitored by optical isotope shift its atomic spectra. (author). 23 refs, 7 figs, 4 tabs.

  2. Beta-Decay Study of ^{150}Er, ^{152}Yb, and ^{156}Yb: Candidates for a Monoenergetic Neutrino Beam Facility

    Energy Technology Data Exchange (ETDEWEB)

    Estevez Aguado, M. E. [CSIC-Universidad de Valencia; Algora, A. [CSIC-Universidad de Valencia; Rubio, B. [CSIC-Universidad de Valencia; Bernabeu, J. [CSIC-Universidad de Valencia; Nacher, E. [CSIC-Universidad de Valencia; Tain, J. L. [CSIC-Universidad de Valencia; Gadea, A. [CSIC-Universidad de Valencia; Agramunt, J. [CSIC-Universidad de Valencia; Burkard, K. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Hueller, W. [GSI-Hemholtzzentrum fur Schwerionenforschung, Darmstadt, Germany; Doring, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kirchner, R. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Mukha, I. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Plettner, C. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Roeckl, E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Grawe, H. [GSI-Hemholtzzentrum fur Schwerionenforschung, Darmstadt, Germany; Collatz, R. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Hellstrom, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Cano-Ott, D. [CIEMAT, Madrid; Karny, M. [University of Warsaw; Janas, Z. [University of Warsaw; Gierlik, M. [University of Warsaw; Plochocki, A. [University of Warsaw; Rykaczewski, Krzysztof Piotr [ORNL; Batist, L. [Petersburg Nuclear Physics Institute, Gatchina, Russia; Moroz, F. [Petersburg Nuclear Physics Institute, Gatchina, Russia; Wittman, V. [Petersburg Nuclear Physics Institute, Gatchina, Russia; Blazhev, A. [University of Cologne; Valiente, J. J. [INFN, Laboratori Nazionali di Legnaro, Italy; Espinoza, C. [CFPT-IST, Lisbon

    2011-01-01

    The beta decays of ^{150}Er, ^{152}Yb, and ^{156}Yb nuclei are investigated using the total absorption spectroscopy technique. These nuclei can be considered possible candidates for forming the beam of a monoenergetic neutrino beam facility based on the electron capture (EC) decay of radioactive nuclei. Our measurements confirm that for the cases studied, the EC decay proceeds mainly to a single state in the daughter nucleus.

  3. Preparation of Mg-Yb alloy film by electrolysis in the molten LiCl-KCl-YbCl_3 system at low temperature

    Institute of Scientific and Technical Information of China (English)

    陈野; 叶克; 张密林

    2010-01-01

    The electrochemical behavior of Yb3+ and electrodeposition of Mg-Yb alloy film at solid magnesium cathode in the molten LiCl-KCl-YbCl3(2 wt.%) system at 773 K was investigated.Transient electrochemical techniques,such as cyclic voltammetry,chronopotentiometry and chronoamperometry were used in order to explore the deposition mechanism of Yb.The reduction process of Yb3+ is stepwise reactions which are single-electron and double-electron reversible charge transfer reactions.The speed control step was a diffu...

  4. MHz Repetion Rate Yb:YAG and Yb:CaF2 Regenerative Picosecond Laser Amplifiers with a BBO Pockels Cell

    Directory of Open Access Journals (Sweden)

    Fedor Bergmann

    2015-10-01

    Full Text Available We present picosecond Yb:YAG and Yb:CaF2 regenerative laser amplifiers with ultra-high repetition rates in the MHz range. A maximum pulse energy of 40 μJ was obtained at 20 kHz while we achieved around 1 μJ at 1 MHz. We demonstrated a pulse duration of 2.1 ps for Yb:YAG and 4.8 ps for Yb:CaF2 when seeded by a mode-locked Yb:KGW fs-oscillator without pulse stretching or phase compensation.

  5. Fiber-optic thermometer application of thermal radiation from rare-earth end-doped SiO{sub 2} fiber

    Energy Technology Data Exchange (ETDEWEB)

    Katsumata, Toru, E-mail: katsumat@toyo.jp; Morita, Kentaro; Komuro, Shuji; Aizawa, Hiroaki [Faculty of Science and Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan)

    2014-08-15

    Visible light thermal radiation from SiO{sub 2} glass doped with Y, La, Ce, Pr, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu were studied for the fiber-optic thermometer application based on the temperature dependence of thermal radiation. Thermal radiations according to Planck's law of radiation are observed from the SiO{sub 2} fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu at the temperature above 1100 K. Thermal radiations due to f-f transitions of rare-earth ions are observed from the SiO{sub 2} fibers doped with Nd, Dy, Ho, Er, Tm, and Yb at the temperature above 900 K. Peak intensities of thermal radiations from rare-earth doped SiO{sub 2} fibers increase sensitively with temperature. Thermal activation energies of thermal radiations by f-f transitions seen in Nd, Dy, Ho, Er, Tm, and Yb doped SiO{sub 2} fibers are smaller than those from SiO{sub 2} fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu. Thermal radiation due to highly efficient f-f transitions in Nd, Dy, Ho, Er, Tm, and Yb ions emits more easily than usual thermal radiation process. Thermal radiations from rare-earth doped SiO{sub 2} are potentially applicable for the fiber-optic thermometry above 900 K.

  6. Static magnetic susceptibility, crystal field and exchange interactions in rare earth titanate pyrochlores

    NARCIS (Netherlands)

    Malkin, B. Z.; Lummen, T. T. A.; van Loosdrecht, P. H. M.; Dhalenne, G.; Zakirov, A. R.

    2010-01-01

    The experimental temperature dependence (T = 2-300 K) of single crystal bulk and site susceptibilities of rare earth titanate pyrochlores R2Ti2O7 (R = Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) is analyzed in the framework of crystal field theory and a mean field approximation. Analytical expressions for the s

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

    Science.gov (United States)

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

    2014-12-03

    We present the structural, magnetic, thermodynamic and transport properties of the two new compounds YbPt(2)Sn and YbPt(2)In. X-ray powder diffraction shows that they crystallize in different structure types, the hexagonal ZrPt(2)Al 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 YbPt(2)Sn and YbPt(2)In, 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 YbPt(2)In 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.

  8. The Yb-Zn-In system at 400 deg. C: Partial isothermal section with 0-33.3 at.% Yb

    Energy Technology Data Exchange (ETDEWEB)

    Verbovytskyy, Yu., E-mail: yuryvv@bigmir.ne [Departamento de Quimica, Instituto Tecnologico e Nuclear/CFMC-UL, Estrada Nacional 10, P-2686 Sacavem Codex (Portugal); Goncalves, A.P. [Departamento de Quimica, Instituto Tecnologico e Nuclear/CFMC-UL, Estrada Nacional 10, P-2686 Sacavem Codex (Portugal)

    2009-11-03

    The phase relations in the ternary system Yb-Zn-In have been established for the partial isothermal section in the 0-33.3 at.% ytterbium concentration range at 400 deg. C, by researching of more than forty alloys. X-ray powder diffraction (XRPD), optical microscopy (OM) and scanning electron microscopy (SEM), complemented with energy dispersive X-ray spectroscopy (EDS), were used to study the microstructures, identify the phases and characterize their crystal structures and compositions. The phase equilibria of this Yb-Zn-In partial section at 400 deg. C are characterized by the presence of three extended homogeneity ranges, indium solubility in Yb{sub 13}Zn{sub 58} and YbZn{sub 2} and of zinc solubility in YbIn{sub 2}, and the existence of one ternary intermetallic compound, YbZn{sub 1-x}In{sub 1+x}, x = approx0.3. This new compound crystallizes in the UHg{sub 2} structure type (space group P6/mmm), with a = 4.7933(5) A, c = 3.6954(5) A. The studied partial isothermal section has eight ternary phase fields at 400 deg. C.

  9. High spin levels in /sup 151/Ho

    Energy Technology Data Exchange (ETDEWEB)

    Gizon, J.; Gizon, A.; Andre, S.; Genevey, J.; Jastrzebski, J.; Kossakowski, R.; Moszynski, M.; Preibisz, Z.

    1981-07-01

    We report here on the first study of the level structure of /sup 151/Ho. High spin levels in /sup 151/Ho have been populated in the /sup 141/Pr + /sup 16/O and /sup 144/Sm + /sup 12/C reactions. The level structure has been established up to 6,6 MeV energy and the spins and parities determined up to 49/2/sup -/. Most of the proposed level configurations can be explained by the coupling of h sub(11/2) protons to fsub(7/2) and/or hsub(9/2) neutrons. An isomer with 14 +- 3 ns half-life and a delayed gamma multiplicity equal to 17 +- 2 has been found. Its spin is larger than 57/2 h units.

  10. High spin levels in /sup 151/Ho

    Energy Technology Data Exchange (ETDEWEB)

    Gizon, J.; Gizon, A.; Andre, S.; Genevey, J.; Jastrzebski, J.; Kossakowski, R.; Moszynski, M.; Preibisz, Z.

    1981-07-01

    We report here on the first study of the level structure of /sup 151/Ho. High spin levels in /sup 151/Ho have been populated in the /sup 141/Pr + /sup 16/O and /sup 144/Sm + /sup 12/C reactions. The level structure has been established up to 6.6 MeV energy and the spins and parities determined up to 49/2/sup -/. Most of the proposed level configurations can be explained by the coupling of hsub(11/2) protons to fsub(7/2) and/or hsub(9/2) neutrons. An isomer with 14 +- 3 ns half-life and a delayed gamma multiplicity equal 17 +- 2 has been found. Its spin is larger than 57/2 h units.

  11. Hard x-ray photoemission study of Yb1-x Zr x B12: the effects of electron doping on the Kondo insulator YbB12

    Science.gov (United States)

    Rousuli, A.; Sato, H.; Iga, F.; Hayashi, K.; Ishii, K.; Wada, T.; Nagasaki, T.; Mimura, K.; Anzai, H.; Ichiki, K.; Ueda, S.; Kondo, A.; Kindo, K.; Takabatake, T.; Shimada, K.; Namatame, H.; Taniguchi, M.

    2017-07-01

    We have carried out hard x-ray photoemission spectroscopy (HAXPES) of Yb1-x Zr x B12 (0≤slant x≤slant 0.875 ) to study the effects of electron doping on the Kondo insulator YbB12. The Yb valences of Yb1-x Zr x B12 at 300 K estimated from the Yb 3d HAXPES spectra decreased after substituting Yb with Zr from 2.93 for YbB12 to 2.83 for Yb0.125Zr0.875B12. A temperature dependent valence decrease was found upon cooling for all doping concentrations. We found peak shifts of the B 1s and Zr 3d5/2, and Yb3+ 4f spectra toward the deeper binding-energy with increasing Zr concentration, which indicates a shift of the Fermi level to the higher energy and that of the Yb 4f hole level close to the Fermi level, respectively, due to electron doping. These results qualitatively show the enhanced hybridization between the Yb 4f and conduction-band states with Zr substitution, consistent with magnetic susceptibility measurements.

  12. Vzduchotechnika sportovního centra

    OpenAIRE

    Šafář, Robert

    2013-01-01

    Bakalářská práce je zaměřena na návrh vzduchotechnického zařízení pro prostor tělocvičny tak, aby splňovalo funkční, hygienické a provozní požadavky na mikroklima sportovních objektů. Hlavními úkoly zařízení jsou pokrytí tepelných ztrát prostoru tělocvičny v zimním období a doprava čerstvého vzduchu do místnosti. Systém je navržen také pro pokrytí letních tepelných zisků. První teoretická část se zabývá způsoby zpětného získávání tepla pro potřeby klimatizace a druhá část obsahuje návrh dvou ...

  13. The Ras antagonist, farnesylthiosalicylic acid (FTS, decreases fibrosis and improves muscle strength in dy/dy mouse model of muscular dystrophy.

    Directory of Open Access Journals (Sweden)

    Yoram Nevo

    Full Text Available The Ras superfamily of guanosine-triphosphate (GTP-binding proteins regulates a diverse spectrum of intracellular processes involved in inflammation and fibrosis. Farnesythiosalicylic acid (FTS is a unique and potent Ras inhibitor which decreased inflammation and fibrosis in experimentally induced liver cirrhosis and ameliorated inflammatory processes in systemic lupus erythematosus, neuritis and nephritis animal models. FTS effect on Ras expression and activity, muscle strength and fibrosis was evaluated in the dy(2J/dy(2J mouse model of merosin deficient congenital muscular dystrophy. The dy(2J/dy(2J mice had significantly increased RAS expression and activity compared with the wild type mice. FTS treatment significantly decreased RAS expression and activity. In addition, phosphorylation of ERK, a Ras downstream protein, was significantly decreased following FTS treatment in the dy(2J/dy(2J mice. Clinically, FTS treated mice showed significant improvement in hind limb muscle strength measured by electronic grip strength meter. Significant reduction of fibrosis was demonstrated in the treated group by quantitative Sirius Red staining and lower muscle collagen content. FTS effect was associated with significantly inhibition of both MMP-2 and MMP-9 activities. We conclude that active RAS inhibition by FTS was associated with attenuated fibrosis and improved muscle strength in the dy(2J/dy(2J mouse model of congenital muscular dystrophy.

  14. Low Noise, tunable Ho:fiber Soliton Oscillator for Ho:YLF Amplifier Seeding

    CERN Document Server

    Li, Peng; Bransley, Colleen; Hartl, Ingmar

    2015-01-01

    We present a passively mode-locked, tunable soliton Ho:fiber ring oscillator, optimized for seeding of Ho:YLF amplifiers. The oscillator is independently tunable in central wavelength and spectral width from 2040 nm to 2070 nm and from 5 nm to 10 nm, respectively. At all settings the pulse energy within the soliton is around 800 pJ. The soliton oscillator was optimized to fully meets the spectral requirements for seeding Ho:YLF amplifiers. Its Kelly sidebands are located outside the amplifier gain spectrum, resulting in a train of about 1 ps long pedestal-free pulses with relative intensity noise (RIN) of only 0.13 % RMS when integrated from 1 Hz to Nyquist frequency.

  15. Low noise, tunable Ho:fiber soliton oscillator for Ho:YLF amplifier seeding

    Science.gov (United States)

    Li, Peng; Ruehl, Axel; Bransley, Colleen; Hartl, Ingmar

    2016-06-01

    We present a passively mode-locked, tunable soliton Ho:fiber ring oscillator, optimized for seeding of holmium-doped yttrium lithium flouride (Ho:YLF) amplifiers. The oscillator is independently tunable in central wavelength and spectral width from 2040 to 2070 nm and from 5 to 10 nm, respectively. At all settings the pulse energy within the soliton is around 800 pJ. The soliton oscillator was optimized to fully meet the spectral requirements for seeding Ho:YLF amplifiers. Its Kelly sidebands are located outside the amplifier gain spectrum, resulting in a train of about 1 ps long pedestal-free pulses with relative intensity noise of only 0.13% RMS when integrated from 1 Hz to Nyquist frequency.

  16. Crystal field excitations of YbMn2Si2

    Science.gov (United States)

    Mole, R. A.; Hofmann, M.; Adroja, D. T.; Moze, O.; Campbell, S. J.

    2013-12-01

    The crystal field excitations of the rare earth intermetallic compound YbMn2Si2 have been measured by inelastic neutron scattering over the temperature range 2.5-50 K. The YbMn2Si2 spectra exhibit three low energy excitations (~3-7 meV) in the antiferromagnetic AFil region above the magnetic phase transition at TN2 = 30(5) K. The crystal field parameters have been determined for YbMn2Si2 in the antiferromagnetic AFil region. A further two inelastic excitations (~9 meV, 17 meV) are observed below TN2=30(5) K, the temperature at which the high temperature antiferromagnetic structure is reported to exhibit doubling of the magnetic cell. Energy level diagrams have been determined for Yb3+ ions in the different sites above (single site) and below the magnetic transition temperature (two sites). The excitation energies for both sites are shown to be temperature independent with the temperature dependences of the transition intensities for the two sites described well by a simple Boltzmann model. The spectra below TN2 cannot be described fully in terms of molecular field models based on either a single Yb3+ site or two Yb3+ sites. This indicates that the magnetic behaviour of YbMn2Si2 is more complicated than previously considered. The inability to account fully for excitations below the magnetic phase transition may be due to an, as yet, unresolved structural transition associated with the magnetic transition.

  17. Thermal and nuclear hyperfine properties of Ho(OH)3

    Science.gov (United States)

    Karmakar, S.

    1985-05-01

    A reasonable explanation for the findings of Catanese and Meissner [Phys. Rev. B 8, 2071 (1973)] regarding the (hyperfine) heat capacity in the low-temperature region of Ho(OH)3 is given. The Schottky specific heat in the high-temperature region observed calorimetrically by Chirico et al. [J. Chem. Thermodyn. 13, 1092 (1981)] explained satisfactorily. Nuclear hyperfine constants for Ho3+ ions in Ho(OH)3 are determined.

  18. Electron Capture in 163Ho and Overlap plus Exchange Corrections and the Neutrino Mass

    CERN Document Server

    Faessler, Amand; Simkovic, M F

    2014-01-01

    Holmium offers perhaps the best chance to determine the neutrino mass by electron capture. This contribution treats the electron capture in 163Holmium completely relativistic for the overlap and exchange corrections. The theoretical expressions are derived consistently in second quantisation with the help of Wick's theorem assuming single Slater determinants for the initial Ho and the final Dy atoms with holes in the final ns1/2 and np1/2 states. No hand waving arguments are needed to derive the exchange terms. It seems, that for the first time the multiplicity of electrons in the orbital overlaps are included in the numerical treatment. Electron capture e + p --> n + neutrino is proportional to the probability to find the captured electron in the parent atom at the nucleus. Non-relativistically this is only possible for ns1/2 electron states. Relativistically also p1/2 electrons have a probability to be at the nucleus due to the lower part of the relativistic electron spinor, which does not disappear at the ...

  19. Study on Micro Electrolysis Treatment for Decolorizing Dyed Water

    Institute of Scientific and Technical Information of China (English)

    王敏欣; 朱书全; 何绪文

    2001-01-01

    Method for decolrizing dyed wastewater was researched and the affecting factors dicussed. The result shows that the conditions for getting an optimum decolorization effect are: a reaction time of 60 min, a coke size of 5~10 mm, a solid/liquid ratio of 1∶10, an air blast volume of 4 m3/h, and proper Fe/coke ratio determined by the type of dye material. The system acidity influences dyed wastewater in different ways, i.e., acid condition is good for the decolorization of scarlet 3R and methyl orange simulated wastewater but bad for that of alkali violet 5BN simulated wastewater, while the decolorization of dispersed yellow E-RGFL simulated wastewater has nothing to do with pH.

  20. Hyperfine Structure and Isotope Shifts in Dy II

    Directory of Open Access Journals (Sweden)

    Dylan F. Del Papa

    2017-01-01

    Full Text Available Using fast-ion-beam laser-fluorescence spectroscopy (FIBLAS, we have measured the hyperfine structure (hfs of 14 levels and an additional four transitions in Dy II and the isotope shifts (IS of 12 transitions in the wavelength range of 422–460 nm. These are the first precision measurements of this kind in Dy II. Along with hfs and IS, new undocumented transitions were discovered within 3 GHz of the targeted transitions. These atomic data are essential for astrophysical studies of chemical abundances, allowing correction for saturation and the effects of blended lines. Lanthanide abundances are important in diffusion modeling of stellar interiors, and in the mechanisms and history of nucleosynthesis in the universe. Hfs and IS also play an important role in the classification of energy levels, and provide a benchmark for theoretical atomic structure calculations.

  1. Quasi-CW Diode Laser End-pumped Yb3+∶GlassMicrochip Laser

    Institute of Scientific and Technical Information of China (English)

    DAI Shixun; HU Lili; LIU Zhuping; HUANG Guosong; JIANG Zhonghong; YASUKAZU Izawa

    2002-01-01

    Quasi-CW diode-pumped Yb3+∶borate glass and Yb3+∶phosphate glass microchip lasers have been reported. From Yb3+∶phosphate glass laser, the maximum average output power was 31 mW and the optical-optical conversion efficiency was 5%.The maximum average output power was 18 mW, and optical-optical conversion efficiency was 3% for Yb3+∶borate glass laser.

  2. Magnetoelectricity of single molecular toroics: The Dy4 ring cluster

    Science.gov (United States)

    Popov, A. I.; Plokhov, D. I.; Zvezdin, A. K.

    2016-11-01

    Spin-electric interactions and magnetic and magnetoelectric properties of the Dy4 ring molecular nanocluster are investigated. The effective spin-electric Hamiltonian is derived on a base of developed quantum mechanical model of the cluster spin structure. It is shown that the toroidal moment is a source of the quantum magnetoelectric effect. The dynamics of the toroidal moment (macroscopic quantum tunneling) is also discussed.

  3. EST Table: DY230642 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available DY230642 EST01377 10/09/28 42 %/114 aa ref|YP_015696.1| polyprotein [Kakugo virus] ...dbj|BAD06930.1| polyprotein [Kakugo virus] 10/09/03 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h DN237490 BmP ...

  4. Cyclic Electrodeposition of Yb-Bi Thin Films

    Institute of Scientific and Technical Information of China (English)

    李高仁; 柯琴芳; 童叶翔; 刘冠昆

    2004-01-01

    Deposition of Yb-Bi thin films was carried out from a nonaqueous solution by using cyclic electrodepositon.During electrodeposition the substrate potential was continuously cycled between two potentials.The effects of several factors including the potential of deposition,time of deposition and sweep rate on the Yb content in the thin films and surface morphology were studied.Experimental results indicate that the amorphous Yb-Bi thin films containing Yb 21.04%~36.36%(mass fraction)can be prepared in 0.10 mol·L-1 YbCl3+0.10 mol*L-1 Bi(NO3)3+0.10 mol·L-1 LiCl+DMSO by controlling deposition conditions of the system.They are black,uniform,metallic luster and adhered firmly to the copper substrates.The films were characterized by X-ray energy dispersive analysis(EDS),scanning electron microcoscope(SEM)and X-ray diffraction(XRD).

  5. PENGENDALIAN DALAM PENERBITAN IZIN GANGGUAN (HO

    Directory of Open Access Journals (Sweden)

    Pebriana Marlinda

    2017-04-01

    Full Text Available Abstrak :            Penelitian tentang pengendalian dalam penerbitan izin gangguan (HO di Kecamatan Margahayu Kabupaten Bandung menjelaskan tentang tahap-tahap pengendalian yang dilakukan oleh aparat Kecamatan Margahayu. Pengendalian dilakukan untuk memastikan agar penerbitan izin gangguan (HO berjalan dengan efektif. Namun, masih ada pelaku usaha yang belum memiliki surat izin gangguan (HO ataupun pelaku usaha yang sudah memiliki surat izin gangguan (HO akan tetapi kegiatan usahanya merugkan orang lain seperti sampah yang berserakan, polusi udara, polusi suara, dan lain-lain.                            Metode penelitian yang digunakan adalah metode penelitian deduktif kualitatif dengan teknik pengumpulan data melalui studi kepustakaan dan studi lapangan yang meliputi observasi dan wawancara mendalam. Adapun penentuan informan dalam penelitian ini dipilih berdasarkan pertimbangan-pertimbangan dengan pihak-pihak yang terkait dalam pengendalian. Kemudian data yang diperoleh dari hasil wawancara dipaparkan dengan langkah-langkah yang meliputi: reduksi data, penyajian data, menarik kesimpulan/verifikasi. Teori yang digunakan penulis dalam penelitian ini adalah teori dari Stephen P. Robbins tentang tahap-tahap pengendalian yaitu: mengukur kinerja aktual, membandingkan kinerja aktual dengan standar, dan mengambil tindakan manajerial.                            Kesimpulan dari hasil penelitian ini adalah pengendalian yang dilakukan olehaparat Kecamatan Margahayu telah melalui tahap-tahap pengendalian yaitu: mengukur kinerja aktual, membandingkan kinerja aktual dengan standar, dan mengambil tindakan manajerial. Namun perlu dilakukan penguatan di setiap tahap pengendalian terutama pada tahap mengukur kinerja aktual dan pada tahap mengambil tindakan manajerial                            Penelitian tentang pengendalian dalam penerbitan izin gangguan (HO di Kecamatan

  6. Influence of Warp Yarn Tension on Cotton Greige and Dyed Woven Fabric Prosperities

    OpenAIRE

    Uzma Syed; Rafique Ahmed Jhatial

    2013-01-01

    Fabric properties such as pilling and abrasion resistance and tensile strength vary when greige fabric is processed further. The quality of dyed fabric depends on the quality of greige fabric. Cotton Plain and Twill weave fabrics were woven at three different warp yarn tension and then dyed using monochlorotriazine, Drimerene Red Cl-5B dye gives difference in fabric properties. The ASTM, American International Standards were used to determine the greige and dyed fabric properties. It has been...

  7. Effect of Ligand Substitution around the Dy(III) on the SMM Properties of Dual-Luminescent Zn-Dy and Zn-Dy-Zn Complexes with Large Anisotropy Energy Barriers: A Combined Theoretical and Experimental Magnetostructural Study.

    Science.gov (United States)

    Costes, Jean Pierre; Titos-Padilla, Silvia; Oyarzabal, Itziar; Gupta, Tulika; Duhayon, Carine; Rajaraman, Gopalan; Colacio, Enrique

    2016-05-02

    The new dinuclear Zn(II)-Dy(III) and trinuclear Zn(II)-Dy(III)-Zn(II) complexes of formula [(LZnBrDy(ovan) (NO3)(H2O)](H2O)·0.5(MeOH) (1) and [(L(1)ZnBr)2Dy(MeOH)2](ClO4) (3) (L and L(1) are the dideprotonated forms of the N,N'-2,2-dimethylpropylenedi(3-methoxysalicylideneiminato and 2-{(E)-[(3-{[(2E,3E)-3-(hydroxyimino)butan-2-ylidene ]amino}-2,2-dimethylpropyl)imino]methyl}-6-methoxyphenol Schiff base compartmental ligands, respectively) have been prepared and magnetostructurally characterized. The X-ray structure of 1 indicates that the Dy(III) ion exhibits a DyO9 coordination sphere, which is made from four O atoms coming from the compartmental ligand (two methoxy terminal groups and two phenoxido bridging groups connecting Zn(II) and Dy(III) ions), other four atoms belonging to the chelating nitrato and ovanillin ligands, and the last one coming to the coordinated water molecule. The structure of 3 shows the central Dy(III) ion surrounded by two L(1)Zn units, so that the Dy(III) and Zn(II) ions are linked by phenoxido/oximato bridging groups. The Dy ion is eight-coordinated by the six O atoms afforded by two L(1) ligands and two O atoms coming from two methanol molecules. Alternating current (AC) dynamic magnetic measurements of 1, 3, and the previously reported dinuclear [LZnClDy(thd)2] (2) complex (where thd = 2,2,6,6-tetramethyl-3,5-heptanedionato ligand) indicate single molecule magnet (SMM) behavior for all these complexes with large thermal energy barriers for the reversal of the magnetization and butterfly-shaped hysteresis loops at 2 K. Ab initio calculations on 1-3 show a pure Ising ground state for all of them, which induces almost completely suppressed quantum tunnelling magnetization (QTM), and thermally assisted quantum tunnelling magnetization (TA-QTM) relaxations via the first excited Kramers doublet, leading to large energy barriers, thus supporting the observation of SMM behavior. The comparison between the experimental and theoretical

  8. Observations of OH and HO2 radicals over West Africa

    Directory of Open Access Journals (Sweden)

    D. E. Heard

    2010-03-01

    Full Text Available The hydroxyl radical (OH plays a key role in the oxidation of trace gases in the troposphere. However, observations of OH and the closely related hydroperoxy radical (HO2 have been sparse, especially in the tropics. Based on a low-pressure laser-induced fluorescence technique (FAGE – Fluorescence Assay by Gas Expansion, an instrument has been developed to measure OH and HO2 aboard the Facility for Airborne Atmospheric Measurement (FAAM BAe-146 research aircraft. The instrument is described and the calibration method is discussed. During the African Monsoon Multidisciplinary Analyses (AMMA campaign, observations of OH and HO2 (HOx were made in the boundary layer and free troposphere over West Africa on 13 flights during July and August 2006. Mixing ratios of both OH and HO2 were found to be highly variable but followed a diurnal cycle, with a median HO2/OH ratio of 95. Daytime OH observations were compared with the primary production rate of OH from ozone photolysis in the presence of water vapour. Daytime HO2 observations were generally reproduced by a simple steady-state HOx calculation, where HOx was assumed to be formed from the primary production of OH and lost through HO2 self-reaction. Deviations between the observations and this simple model were found to be grouped into a number of specific cases: (a in the presence of high levels of isoprene in the boundary layer, (b within a biomass burning plume and (c within cloud. In the forested boundary layer, HO2 was underestimated at altitudes below 500 m but overestimated between 500 m and 2 km. In the biomass burning plume, OH and HO2 were both significantly reduced compared to calculations. HO2 was sampled in and around cloud, with significant short-lived reductions of HO2 observed. HO2 observations were better reproduced by a steady state calculation with heterogeneous loss of HO2 onto cloud droplets included. Up to 9 pptv of HO2 was observed at night, increasing early in the morning

  9. Effect of LiF on Densification and Mechanical Properties of Dy-α-Sialon Ceramics

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effect of LiF on the densification and mechanical properties of hot-pressed Dy-α-sialon ceramics was studied. Comparatively, without LiF as sintering additive, the pure Dy-α-sialon ceramic should be sintered at 1750 ℃. When LiF is used, the sintering temperature of the Dy-α-sialon is greatly lowered to 1500~1650 ℃. Obviously, the addition of LiF has a strong effect on the improvement in densification. Meanwhile, the resultant Dy-α-sialon has no significant changes in the mechanical properties.

  10. Phase relationship of Dy-Fe-Mn system at 773 K

    Institute of Scientific and Technical Information of China (English)

    杜成梅; 马君; 姚路; 陈国坚; 杨通晗; 曾维敬; 何维

    2014-01-01

    Rare-earth intermetallic compounds formed in many R-Fe-Mn (R=rare-earth element) systems exhibit excellent properties. In order to understand the existence and stability of the compounds in the system and further search for the potential application of R-Fe-Mn alloys in various aspects, it is necessary to investigate the phase relations of the Dy-Fe-Mn ternary system. A total of 96 samples of the Dy-Fe-Mn alloys were prepared by arc-melting and examined by metallographic analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques. The phase relationship of the Dy-Fe-Mn system at 773 K was determined. It was found that the isothermal section was characterized by intermediate solid solutions based on the substitutions of Fe/Mn atoms and the large extensions of the binaries into the ternary domains. The solid solubilities of the third ele-ment in the binary compounds and the phase boundaries were also determined by XRD technique using the phase disappearing method combined with the lattice parameter method and SEM/EDS technique. Two pairs of corresponding binary compounds in the Dy-Fe and Dy-Mn systems (DyFe2 and DyMn2, Dy6Fe23 and Dy6Mn23) formed a continuous series of solid solution at 773 K, respectively.

  11. Yellow persistent luminescence of Sr2SiO4:Eu2+,Dy3+

    NARCIS (Netherlands)

    Dutczak, D.A.; Milbrat, A.; Katelnikovas, A.; Meijerink, A.; Ronda, R.C.; Jüstel, T.

    2012-01-01

    This paperreportsthephotoluminescenceandafterglowofSr2SiO4 doped withEu2þ and Dy3þ. Factors governingtheformationofthemonoclinicororthorhombicphaseofthisortho-silicatearedescribed and theimpactofthecrystallographicmodificationontheluminescenceandafterglowunderUVand VUV

  12. Synthesis and Characterization of a Novel Compound SnDy2O4

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new phase, the rare earth complex oxide SnDy2O4 was synthesized by the thermal decomposition of its oxalate precursor that was prepared by rheological phase reaction method. TG, IR, XRD and EPS were used to prove the formation of the compound SnDy2O4. The structure of SnDy2O4 was refined by Rietveld analysis. SnDy2O4 is cubic, a = 7.40366A, V = 405.82A3, Z = 4.

  13. A structural and functional perspective of DyP-type peroxidase family.

    Science.gov (United States)

    Yoshida, Toru; Sugano, Yasushi

    2015-05-15

    Dye-decolorizing peroxidase from the basidiomycete Bjerkandera adusta Dec 1 (DyP) is a heme peroxidase. This name reflects its ability to degrade several anthraquinone dyes. The substrate specificity, the amino acid sequence, and the tertiary structure of DyP are different from those of the other heme peroxidase (super)families. Therefore, many proteins showing the similar amino acid sequences to that of DyP are called DyP-type peroxidase which is a new family of heme peroxidase identified in 2007. In fact, all structures of this family show a similar structure fold. However, this family includes many proteins whose amino acid sequence identity to DyP is lower than 15% and/or whose catalytic efficiency (kcat/Km) is a few orders of magnitude less than that of DyP. A protein showing an activity different from peroxidase activity (dechelatase activity) has been also reported. In addition, the precise physiological roles of DyP-type peroxidases are unknown. These facts raise a question of whether calling this family DyP-type peroxidase is suitable. Here, we review the differences and similarities of structure and function among this family and propose the reasonable new classification of DyP-type peroxidase family, that is, class P, I and V. In this contribution, we discuss the adequacy of this family name.

  14. Charge transfer in the cold Yb$^+$ + Rb collisions

    CERN Document Server

    Sayfutyarova, Elvira R; Yakovleva, Svetlana A; Belyaev, Andrey K

    2013-01-01

    Charge-transfer cold Yb$^+$ + Rb collision dynamics is investigated theoretically using high-level {\\it ab initio} potential energy curves, dipole moment functions and nonadiabatic coupling matrix elements. Within the scalar-relativistic approximation, the radiative transitions from the entrance $A^1\\Sigma^+$ to the ground $X^1\\Sigma^+$ state are found to be the only efficient charge-transfer pathway. The spin-orbit coupling does not open other efficient pathways, but alters the potential energy curves and the transition dipole moment for the $A-X$ pair of states. The radiative, as well as the nonradiative, charge-transfer cross sections calculated within the $10^{-3}-10$ cm$^{-1}$ collision energy range exhibit all features of the Langevin ion-atom collision regime, including a rich structure associated with centrifugal barrier tunneling (orbiting) resonances. Theoretical rate coefficients for two Yb isotopes agree well with those measured by immersing Yb$^+$ ion in an ultracold Rb ensemble in a hybrid trap....

  15. Towards a quantum gas of polar YbCs molecules

    Science.gov (United States)

    Freytag, R.; Petersen, M.; Hinds, E. A.; Tarbutt, M.; Butler, K.; Kemp, S.; Hopkins, S. A.; Brue, D. A.; Hutson, J. M.; Cornish, S. L.

    2013-05-01

    The potentials of ultracold polar molecules have been discussed with respect to quantum information processing and quantum simulation. This experiment focuses on the production of quantum degenerate YbCs molecules. We propose to magneto-associate the atoms over a Feshbach resonance and transfer them to the ground state using Stimulated Raman Adiabatic Passage (STIRAP). Ground state YbCs will, due to its single valence electron, exhibit an electric as well as a magnetic dipole moment. It should therefore demonstrate spin dependent interactions in addition to long-range dipole-dipole interactions. Here we outline the theoretical and experimental progress on creating a dual species Magneto-Optical Trap (MOT) of Yb and Cs. ESPRC

  16. Structure change of 156Yb at high-spin states

    Institute of Scientific and Technical Information of China (English)

    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

    2009-01-01

    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.

  17. Er3+-Yb3+ codoped borosilicate glass for optical thermometry

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Infrared to green up-conversion emissions centered at the wavelengths of about 524 and 550 nm of the Er3+-Yb3+ codoped borosilicate glass are recorded,using a 978 nm semiconductor laser diode(LD) as an excitation source.The fluorescence intensity ratio(FIR) of the green up-conversion emissions at about 524 and 550 nm in the Er3+-Yb3+ codoped borosilicate glass has been studied as a function of temperature over the temperature range of 295-873 K.The maximum sensitivity and the temperature resolution derived from the FIR of the green up-conversion emissions are approximately 0.0038 K-1 and 0.2 K,respectively.It is demonstrated that the prototype optical temperature sensor based on the FIR technique from the green up-conversion emissions in the Er3+-Yb3+ codoped borosilicate glass plays a major role in temperature measurement.

  18. Magnetic phase diagram of Ho-Ag

    Energy Technology Data Exchange (ETDEWEB)

    Paul-Boncour, V [Chimie Metallurgique des Terres Rares, ICMPE, CNRS, 2 rue H Dunant, 94320 Thiais (France); Hoser, A; Stuesser, N [Hahn-Meitner Institut, Glienicker Strasse 100, 14109, Berlin (Germany); Hense, K; Gratz, E [Institute for Experimental Physics, Technical University Vienna, Wiedner Hauptstrasse 8-10, A-1040 (Austria); Rotter, M [Institut fuer Physikalische Chemie, Universitaet Wien, Waehringerstrasse 42, 1090 Wien (Austria)], E-mail: paulbon@glvt-cnrs.fr

    2008-03-12

    The magnetic phase diagram of Ho-Ag has been established using magnetoresistance, magnetostriction and neutron diffraction experiments versus applied field and temperature. Three different magnetic phases were observed: an incommensurate antiferromagnetic phase (IC) below T{sub N} = 33 K, a commensurate antiferromagnetic phase (C) above 5 T and below T{sub 1} (5-8 K) and a ferromagnetic component above 3 T. The IC phase undergoes spin reorientations around 5 T (IC') and 13 T (IC'')

  19. Functional conservation of rice OsNF-YB/YC and Arabidopsis AtNF-YB/YC proteins in the regulation of flowering time

    KAUST Repository

    Hwang, Yoon-Hyung

    2016-01-11

    Plant NUCLEAR FACTOR Y (NF-Y) transcription factors play important roles in plant development and abiotic stress. In Arabidopsis thaliana, two NF-YB (AtNF-YB2 and AtNF-YB3) and five NF-YC (AtNF-YC1, AtNF-YC2, AtNF-YC3, AtNF-YC4, and AtNF-YC9) genes regulate photoperiodic flowering by interacting with other AtNF-Y subunit proteins. Three rice NF-YB (OsNF-YB8, OsNF-YB10, and OsNF-YB11) and five rice OsNF-YC (OsNF-YC1, OsNF-YC2, OsNF-YC4, OsNF-YC6, and OsNF-YC7) genes are clustered with two AtNF-YB and five AtNF-YC genes, respectively. To investigate the functional conservation of these NF-YB and NF-YC genes in rice and Arabidopsis, we analyzed the flowering phenotypes of transgenic plants overexpressing the respective OsNF-YB and OsNF-YC genes in Arabidopsis mutants. Overexpression of OsNF-YB8/10/11 and OsNF-YC2 complemented the late flowering phenotype of Arabidopsis nf-yb2 nf-yb3 and nf-yc3 nf-yc4 nf-yc9 mutants, respectively. The rescued phenotype of 35S::OsNF-YC2 nf-yc3 nf-yc4 nf-yc9 plants was attributed to the upregulation of FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1). In vitro and in planta protein–protein analyses revealed that OsNF-YB8/10/11 and OsNF-YC1/2/4/6/7 interact with AtNF-YC3/4/9 and AtNF-YB2/3, respectively. Our data indicate that some OsNF-YB and OsNF-YC genes are functional equivalents of AtNF-YB2/3 and AtNF-YC3/4/9 genes, respectively, and suggest functional conservation of Arabidopsis and rice NF-Y genes in the control of flowering time.

  20. Measurement of thermal lensing in end-pumped Yb-doped yttrium vanadate crystal and sesquioxide laser ceramics

    Science.gov (United States)

    Pestryakov, E. V.; Petrov, V. V.; Trunov, V. I.; Kirpichnikov, A. V.; Merzliakov, M. A.; Laptev, A. V.; Polyakov, K. V.

    2011-02-01

    The results of theoretical and experimental study of thermal lensing in diode-pumped Yb:YVO4 laser crystal, Yb:Y2O3 and Yb:Sc2O3 laser ceramics are presented. Shown, that influence of thermo-lensing effect is necessary to consider for creation of effective high-intensity femtosecond Yb-doped laser systems.

  1. Investigation of lasing characteristics of domestic Yb : YAG laser ceramics

    Science.gov (United States)

    Snetkov, I. L.; Palashov, O. V.; Osipov, V. V.; Mukhin, I. B.; Maksimov, R. N.; Shitov, V. A.; Luk'yashin, K. E.

    2016-07-01

    We report on the synthesis and laser characteristics of Yb3+-doped yttrium aluminium garnet (Y3Al5O12) optical ceramics. The ceramics was produced by solid-phase reactive sintering of a mixture of Yb (5 at %) : Y2O3 and Al2O3 nanopowders synthesised by laser ablation, using additional calcination of the mixture before compaction. In a thin disk geometry, multiwatt laser oscillation was obtained at a wavelength of 1030 nm with a power of 5.2 W and a slope efficiency of 37.0% at a pump pulse period-toduration ratio of 5.72.

  2. CW Yb:YAG LASER FOR PORTABLE MEASURING SYSTEMS

    Directory of Open Access Journals (Sweden)

    A. M. Ivashko

    2014-01-01

    Full Text Available The theoretical and experimental results of longitudinally continuous-wave diode-pumped Yb:Y3Al5O12 (YAG laser performance for compact field-condition measuring systems were demonstrated. Optimization of laser setup in terms of operation condition in the range of -40 ˚С – +65 ˚С without active thermal stabilization was carried out. Using Yb (10 ат.%:YAG crystal with the length of 3 mm the maximal output power more than 2 W was obtained in the whole of temperature range.

  3. Effects of Dy, Sr and Die Casting on Microstructure, Mechanical and Corrosion Properties of Mg-Dy-Sr-Nd-Zr Alloys

    Science.gov (United States)

    Liu, Dexue; Yin, Xunyan; Pang, Xin; Hu, Shiwen; Ding, Yutian

    2017-08-01

    By adding 2, 6 and 10 wt.% Dy and 0.5, 1.5 and 2 wt.% Sr elements to Mg-2.4Nd-0.5Zr alloys and adopting die-casting process for biomedical Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloys, the effects of Dy and Sr elements and die-casting process on the microstructure, mechanical properties and corrosion resistance of Mg-Dy-Sr-Nd-Zr alloys were investigated. The new biomedical Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloys were designed, and the grain size of the as-cast new alloy was refined to 70 μm and distributed equably. The ultimate tensile strength increased with increasing Dy content and decreasing Sr content. The corrosion rate decreased firstly and then increased with increasing Dy content and decreased with increasing Sr content. By adjusting the content of Sr and Dy, the ultimate tensile strength of as-cast new Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloys increased to 203 MPa, elongation was 7.4%, and the corrosion rate decreased to 0.48 mm/a. The elongation rate increased to 10.2% after the new biomedical alloys were processed by die casting with an refine-grained microstructure of 18 μm, meanwhile the ultimate tensile strength decreased to 180 MPa, and the corrosion rate was 1.29 mm/a.

  4. Study on Electrodeposition of Ho-Co Alloy in Dimethylsulfoxide

    Institute of Scientific and Technical Information of China (English)

    王宇; 刘冠昆; 童叶翔

    2002-01-01

    Co-deposition of Ho with Co was studied in dimethylsulfoxide (DMSO) by cyclic voltammetry and potentiostatic deposition at room temperature. The cyclic voltammogram shows that the codeposition of Ho with Co can be attributed to induced codeposition mechanism, for the codeposition potential is more negative than the deposition potential of Co but positive than that of Ho. For the potentiostatic deposition used in Ho-Co alloys preparation, the results indicate that in the range of selected concentration the potential is the main factor determining the content of Ho in Ho-Co alloys, while the composition of Ho3+ and Co2+ in electrolyte solution has less influence. According to the analysis of X-ray diffraction, EDAX, and scanning electron microscopy, uniform, compact and amorphous films on Cu can be obtained at -1.8 V (vs.SCE) in 0.165 molL-1 Ho(NO3) -0.135 mol*L-1 CoCl2-DMSO solution.

  5. Properties of the divalent-Yb compound YbAu{sub 2}Si{sub 2} under extreme conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kaštil, J.; Míšek, M.; Kamarád, J.; Arnold, Z. [Institute of Physics AS CR, v.v.i., Na Slovance 1999/2, 182 21 Prague 8 (Czech Republic); Vlášková, K. [Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 12116 Prague 2 (Czech Republic); Prchal, J., E-mail: prchal@karlov.mff.cuni.cz [Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 12116 Prague 2 (Czech Republic); Diviš, M.; Doležal, P.; Prokleška, J.; Valenta, J.; Fikáček, J.; Rudajevová, A.; Kriegner, D. [Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 12116 Prague 2 (Czech Republic)

    2017-01-15

    Polycrystalline YbAu{sub 2}Si{sub 2} has been prepared by arc melting and a non-standard anisotropic thermal expansion is observed at low temperatures. A non-magnetic Yb{sup 2+} valence state is derived from magnetization, magnetic-susceptibility, heat-capacity and electrical-conductivity measurements in the temperature range from 0.3 to 300 K and at external pressures up to 3.2 GPa. By both experimental and theoretical investigations, YbAu{sub 2}Si{sub 2} is confirmed to be a system with a weak electron-electron correlations and a small electron-phonon interaction. Application of hydrostatic pressure does not reveal any change of state in the range of applied pressures.

  6. Existing form and effect of zirconium in pure Mg, Mg-Yb, and Mg-Zn-Yb alloys

    Institute of Scientific and Technical Information of China (English)

    YU Wenbin; HE Hong; LI Chunmei; LI Qing; LIU Zhiyi; QIN Bing

    2009-01-01

    The existing form and grain refining effects of small zirconium addition in pure Mg, Mg-Yb and Mg-Zn binary alloys, and Mg-Zn-Yb ternary alloy (ZK60-Yb) were investigated. The results show that Zr element exists mainly in single and cluster particles of pure α-Zr or Zn-Zr compounds inside grains and at grain boundaries. Only the particles located in the interior of grains can act as the nucleus for α-Mg growth and effectively promote the formation of Fine equiaxed grains. The broken and dispersed Zr-rich particles produced during the hot extrusion process can form nebulous banded structure in which these free particles may act as obstacles to dislocation motion in wrought magnesium alloys.

  7. White light generation in Dy{sup 3+}-and Ce{sup 3+}/Dy{sup 3+}-doped zinc–sodium–aluminosilicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Caldiño, U., E-mail: cald@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 México, D.F. (Mexico); Lira, A. [Departamento de Física , Facultad de Ciencias, Universidad Autónoma del estado de México, C.P. 50000 Toluca (Mexico); Meza-Rocha, A.N. [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 México, D.F. (Mexico); Pasquini, E. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, Sesto Fiorentino, 50019 Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, Sesto Fiorentino, 50019 Firenze (Italy); Pelli, S. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, Sesto Fiorentino, 50019 Firenze (Italy); Speghini, A. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, Sesto Fiorentino, 50019 Firenze (Italy); Dipartimento di Biotecnologie, Università di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); Bettinelli, M. [Dipartimento di Biotecnologie, Università di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); Righini, G.C. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, Sesto Fiorentino, 50019 Firenze (Italy); Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Piazza del Viminale 2, 00184 Roma (Italy)

    2015-11-15

    A spectroscopic investigation of 1% Dy{sub 2}O{sub 3}-singly doped and 0.5% Ce{sub 2}O{sub 3}-1.0% Dy{sub 2}O{sub 3}-codoped zinc–sodium–aluminosilicate glasses was performed by analyzing their absorption and photoluminescence spectra, and decay times. Warm white yellow light emission, with (0.419, 0.440) CIE1931 chromaticity coordinates and 3579 K color temperature, is obtained in the Dy{sup 3+}-singly doped glass excited at 399 nm, which fits to the requirements of GaN LEDs. A quantum efficiency of 74% and a very high optical gain (38.7×10{sup −25} cm{sup 2} s) were estimated for the dysprosium {sup 4}F{sub 9/2} level luminescence, which might also make the Dy{sup 3+}-doped glass a promising gain medium for solid state yellow laser pumped by GaN LEDs. In the Ce{sup 3+}/Dy{sup 3+}-codoped glass a radiative energy transfer from Ce{sup 3+} to Dy{sup 3+} is observed upon UV excitation (310–365 nm), with a Ce{sup 3+} to Dy{sup 3+} interaction distance that could be greater than 6–12 Å. The emission color from the codoped glass can be tuned with the excitation wavelength from blue light (0.247, 0.245), upon 310 nm excitation, to cold white light (0.284, 0.300), with a 9052 K color temperature, upon 365 nm excitation. - Highlights: • Zinc–sodium–aluminosilicate (ZN) glasses are optically activated with Dy{sup 3+} (ZNDy). • ZN glasses are optically activated with Ce{sup 3+}/Dy{sup 3+} (ZNCeDy). • Dy{sup 3+} is sensitized by Ce{sup 3+} through a radiative energy transfer. • ZNDy glass can generate 3579 K warm white yellow light emission. • ZNCeDy glass can generate 9052 K cold white light emission.

  8. Spectroscopic properties of Dy(3+) doped ZnO for white luminescence applications.

    Science.gov (United States)

    Amira, Guesmi; Chaker, Bouzidi; Habib, Elhouichet

    2017-04-15

    Undoped and Dy(3+) (0.25, 0.5, 0.8 and 1.5at.%) doped ZnO were elaborated by solid-state reaction method. The ZnO:Dy(3+) samples were characterized using X-ray diffraction (XRD), Raman spectroscopy, UV-vis diffuse reflectance spectroscopy and photoluminescence (PL). The XRD analysis confirms the wurtzite structure of ZnO. A slight shift to lower angles, of the (101) peak, is seen with Dy(3+) content, indicating the substitution of these ions into the ZnO lattice. Raman study indicates the good crystallinity of all ZnO:Dy(3+) samples and confirms the substitution of Zn(2+) by Dy(3+). The band gap energy was found to increase then decrease with Dy content. The PL excitation spectra (PLE) of Dy(3+) showed six excitation bands with hypersensitive at 346nm ((6)H15/2→(6)P7/2). PL spectra show principally three emission bands relatives to (4)F9/2→(6)H15/2 (476nm), (4)F9/2→(6)H13/2 (567nm) and (4)F9/2→(6)H11/2 (658nm) transitions. The concentration dependency of PL intensity indicates a quenching for Dy(3+) concentration above 0.5at.%. The PL lifetime of (4)F9/2 metastable state was measured and discussed for all Dy content in ZnO. The temperature dependency of PL intensity is investigated for ZnO:Dy (0.5%) sample and the activation energy is determined. The CIE chromaticity color coordinate shows that ZnO:Dy(3+) can be useful for white luminescence applications.

  9. Photoluminescence of atomic layer deposited ZrO{sub 2}:Dy{sup 3+} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kiisk, Valter, E-mail: valter.kiisk@ut.ee; Tamm, Aile; Utt, Kathriin; Kozlova, Jekaterina; Mändar, Hugo; Puust, Laurits; Aarik, Jaan; Sildos, Ilmo

    2015-05-29

    Atomic layer deposition based on alternate cycling of ZrCl{sub 4}, Dy(thd){sub 3} and H{sub 2}O as precursors was applied for preparation of nanocrystalline ZrO{sub 2}:Dy thin films. Photoluminescence (PL) properties of Dy{sup 3+} in the ZrO{sub 2} films were studied at several laser excitations. Substantial activation of Dy{sup 3+} PL required thermal treatment at 900 °C. As a result of annealing, thinner (~ 80 nm) films with higher Dy content retained relatively high amount of tetragonal phase and remained crack-free. In thicker (~ 140 nm) films, considerable amount of monoclinic phase was formed and a peculiar microscale cracking pattern was developed along with phase segregation. It is demonstrated that the crystal structure of ZrO{sub 2} significantly influences the Dy{sup 3+} emission spectrum and, at least for ZrO{sub 2}-type matrices, Dy{sup 3+} is an excellent luminescent microprobe in comparison with micro-Raman scattering. A Förster-like PL decay profile allowed a conclusion that the self-quenching due to cross-relaxation between Dy{sup 3+} ions had a marked impact on emission intensity. - Highlights: • Atomic layer deposition of luminescent Dy-doped ZrO{sub 2} thin films was demonstrated. • Dy{sup 3+} luminescence was significantly activated only after high-temperature annealing. • Correlation between luminescent and structural properties was obtained. • Dy{sup 3+} luminescent probe showed superior performance compared to Raman-scattering. • Presence of several quenching processes was deduced from luminescence behavior.

  10. Spectroscopic properties of Dy3 + doped ZnO for white luminescence applications

    Science.gov (United States)

    Amira, Guesmi; Chaker, Bouzidi; Habib, Elhouichet

    2017-04-01

    Undoped and Dy3 + (0.25, 0.5, 0.8 and 1.5 at.%) doped ZnO were elaborated by solid-state reaction method. The ZnO:Dy3 + samples were characterized using X-ray diffraction (XRD), Raman spectroscopy, UV-vis diffuse reflectance spectroscopy and photoluminescence (PL). The XRD analysis confirms the wurtzite structure of ZnO. A slight shift to lower angles, of the (101) peak, is seen with Dy3 + content, indicating the substitution of these ions into the ZnO lattice. Raman study indicates the good crystallinity of all ZnO:Dy3 + samples and confirms the substitution of Zn2 + by Dy3 +. The band gap energy was found to increase then decrease with Dy content. The PL excitation spectra (PLE) of Dy3 + showed six excitation bands with hypersensitive at 346 nm (6H15/2 → 6P7/2). PL spectra show principally three emission bands relatives to 4F9/2 → 6H15/2 (476 nm), 4F9/2 → 6H13/2 (567 nm) and 4F9/2 → 6H11/2 (658 nm) transitions. The concentration dependency of PL intensity indicates a quenching for Dy3 + concentration above 0.5 at.%. The PL lifetime of 4F9/2 metastable state was measured and discussed for all Dy content in ZnO. The temperature dependency of PL intensity is investigated for ZnO:Dy (0.5%) sample and the activation energy is determined. The CIE chromaticity color coordinate shows that ZnO:Dy3 + can be useful for white luminescence applications.

  11. Sequential growth of sandwiched NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb core–shell–shell nanoparticles for photodynamic therapy

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Huang-Yong; Ding, Bin-Bin; Ma, Yin-Chu [Department of Medical Materials and Rehabilitation Engineering, School of Medical Engineering, Hefei University of Technology, Hefei 230009 (China); Sun, Shi-Qi [State Key Laboratory of Veterinary Etiological Biology and Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Lanzhou, Gansu 730046 (China); Tao, Wei [Department of Medical Materials and Rehabilitation Engineering, School of Medical Engineering, Hefei University of Technology, Hefei 230009 (China); Guo, Yan-Chuan [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Guo, Hui-Chen, E-mail: ghch-2004@hotmail.com [State Key Laboratory of Veterinary Etiological Biology and Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Lanzhou, Gansu 730046 (China); Yang, Xian-Zhu, E-mail: yangxz@hftu.edu.cn [Department of Medical Materials and Rehabilitation Engineering, School of Medical Engineering, Hefei University of Technology, Hefei 230009 (China); Qian, Hai-Sheng, E-mail: shqian@hfut.edu.cn [Department of Medical Materials and Rehabilitation Engineering, School of Medical Engineering, Hefei University of Technology, Hefei 230009 (China)

    2015-12-01

    Graphical abstract: The monodisperse elliptical NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb core–shell–shell nanoparticles have been synthesized successfully by a facile sequential growth process, which can be used as transducer for photodynamic therapy of cancer cells. - Highlights: • The NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb nanoparticles have been fabricated successfully. • The as-prepared nanoparticles show strong fluorescence excited at 980 or 808 nm. • The nanoparticles were transferred into the aqueous phase via a facile process. • Photosensitizers were loaded into the composites for photodynamic therapy. - Abstract: Upconversion (UC) nanostructures have attracted much interest for their extensive biological applications. In this work, we describe a sequential synthetic route to prepare sandwiched NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb core–shell upconversion nanoparticles. The as-prepared products were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM, JEM 2100F), respectively. The as-prepared core–shell nanoparticles of NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb are composed of elliptical nanoparticles with a length of 80 nm and width of 42 nm, which show efficient upconversion fluorescence excited at 808 nm indicating the formation of core–shell–shell sandwiched nanostructures. In addition, the as-prepared sandwiched NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb core–shell upconversion nanoparticles also show strong upconversion fluorescence excited at 980 nm. Amphiphilic mPEG{sub 2k}-b-PEBEP{sub 6K} copolymers (denoted as PPE) were chosen to transfer these hydrophobic UCNPs into the aqueous phase for biological application. In vitro photodynamic therapy of cancer cells show that the viability of cells incubated with the nanoparticles loaded with MC 540 was significantly lower as compared to the nanoparticles without photosensitizers exposed to NIR laser.

  12. DyCl3-NaCl体系相图的热力学优化计算%Thermodynamic Optimization of DyCl3 -NaCl System

    Institute of Scientific and Technical Information of China (English)

    叶信宇; 孙益民; 张静; 谈君君

    2005-01-01

    In this paper, the phase diagram of the DyCl3-NaC1 system is optimized and calculated with CALPHAD (calculation of phase diagram) technology. A set of thermodynamic functions of compounds Na3 DyCl6, NaDyCl4, and NaDy2 Cl7 have been optimized and calculated based on an interactive computer-assisted analysis. The optimized thermodynamic parameters, calculated phase diagram and experimental phase diagram are thermodynamically self-consistent.

  13. Electron spin resonance in Yb-based Kondo-lattice systems; Elektronenspinresonanz in Yb-basierten Kondogitter-Systemen

    Energy Technology Data Exchange (ETDEWEB)

    Wykhoff, Jan

    2010-07-07

    The systems Yb{sub 1-w}A{sub 1-w}(Rh{sub 1-x}Co{sub x})(Si{sub 1-y}Ge{sub y}){sub 2} with A=La respectively Lu, as well as YbIr{sub 2}Si{sub 2} are studied. The measurements are presented sortedly for systems, dopings, and external parameters. Beside these external parameters furthermore the orientation of the sample related to the quasistatic magnetic field and the microwave magnetic field was varied.

  14. Multiple transformation with the crtYB gene of the limiting enzyme increased carotenoid synthesis and generated novel derivatives in Xanthophyllomyces dendrorhous.

    Science.gov (United States)

    Ledetzky, Nadine; Osawa, Ayako; Iki, Kanoko; Pollmann, Hendrik; Gassel, Sören; Breitenbach, Jürgen; Shindo, Kazutoshi; Sandmann, Gerhard

    2014-03-01

    Xanthophyllomces dendrorhous (in asexual state named as Phaffia rhodozyma) is a fungus which produces astaxanthin, a high value carotenoid used in aquafarming. Genetic pathway engineering is one of several steps to increase the astaxanthin yield. The limiting enzyme of the carotenoid pathway is phytoene synthase. Integration plasmids were constructed for transformation with up to three copies of the crtYB gene. Upon stepwise transformation, the copy numbers of crtYB was continuously increased leading to an almost saturated level of phytoene synthase as indicated by total carotenoid content. Several carotenoid intermediates accumulated which were absent in the wild type. Some of them are substrates and intermediates of astaxanthin synthase. They could be further converted into astaxanthin by additional transformation with the astaxanthin synthase gene. However, three intermediates exhibited an unusual optical absorbance spectrum not found before. These novel keto carotenoid were identified by HPLC co-chromatography with reference compounds generated in Escherichia coli and one of them 3-HO-4-keto-7',8'-dihydro-β-carotene additionally by NMR spectroscopy. The others were 4-keto-β-zeacarotene and 4-keto-7',8'-dihydro-β-carotene. A biosynthesis pathway with their origin from neurosporene and the reason for their synthesis especially in our transformants has been discussed.

  15. Genome-wide analysis of the human Alu Yb-lineage

    Directory of Open Access Journals (Sweden)

    Carter Anthony B

    2004-03-01

    Full Text Available Abstract The Alu Yb-lineage is a 'young' primarily human-specific group of short interspersed element (SINE subfamilies that have integrated throughout the human genome. In this study, we have computationally screened the draft sequence of the human genome for Alu Yb-lineage subfamily members present on autosomal chromosomes. A total of 1,733 Yb Alu subfamily members have integrated into human autosomes. The average ages of Yb-lineage subfamilies, Yb7, Yb8 and Yb9, are estimated as 4.81, 2.39 and 2.32 million years, respectively. In order to determine the contribution of the Alu Yb-lineage to human genomic diversity, 1,202 loci were analysed using polymerase chain reaction (PCR-based assays, which amplify the genomic regions containing individual Yb-lineage subfamily members. Approximately 20 per cent of the Yb-lineage Alu elements are polymorphic for insertion presence/absence in the human genome. Fewer than 0.5 per cent of the Yb loci also demonstrate insertions at orthologous positions in non-human primate genomes. Genomic sequencing of these unusual loci demonstrates that each of the orthologous loci from non-human primate genomes contains older Y, Sg and Sx Alu family members that have been altered, through various mechanisms, into Yb8 sequences. These data suggest that Alu Yb-lineage subfamily members are largely restricted to the human genome. The high copy number, level of insertion polymorphism and estimated age indicate that members of the Alu Yb elements will be useful in a wide range of genetic analyses.

  16. Design netradičního sedacího prvku městského mobiliáře

    OpenAIRE

    Haltof, Vladimír

    2014-01-01

    Disertační práce se zabývá designem sedacího prvku městského mobiliáře (lavičky) sloučením pohledů dvou příbuzných oborů – průmyslového designu a architektury. Tvůrčí výstupy práce, které reagují na problémy městského mobiliáře v urbanistickém prostoru, byly od samého počátku cíleny jako design s ambicí reálné produkce. Proto je součástí práce několik ověřovacích kroků potvrzujících realizovatelnost navržených řešení. Prvním výstupem je design sedacího prvku inovativní koncepce s netradičním ...

  17. Polytypic phase formation in DyAl sub 3 by rapid solidification

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y.; Altounian, Z.; Muir, W.B. (Centre for the Physics of Materials and the Department of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada (CA))

    1991-01-14

    Amorphous ribbons of Al{sub {ital x}}Dy{sub 100{minus}{ital x}}, 93{gt}{ital x}{gt}85, were obtained by melt spinning. During crystallization, in addition to Al, four different metastable crystalline phases of DyAl{sub 3} were observed. These phases are, in order of appearance, the high-pressure face-centered cubic phase, {gamma}-DyAl{sub 3} and three polytypic rhombohedral phases, {beta}-DyAl{sub 3}, {beta}{prime}-DyAl{sub 3}, and {alpha}{prime}-DyAl{sub 3}. It is the first time that the {beta}{prime} phase in rare-earth trialuminides and the {alpha}{prime} phase in Dy-Al alloy system have been observed. It is shown that all these phases are associated with the polytypic packing of the hexagonal DyAl{sub 3} atomic layers. The relative stability of the phases is found to be related to the hexagonal to cubic stacking ratio in the structure.

  18. Evaluation of the exchange interaction and crystal fields in a prototype Dy2 SMM

    Science.gov (United States)

    Zhang, Qing; Sarachik, Myriam; Baker, Michael; Chen, Yizhang; Kent, Andrew; Pineda, Eufemio; McInnes, Eric

    In order to gain an understanding of the INS and magnetization data obtained for Dy2, the simplest member of a newly synthesized family of dysprosium-based molecular magnets, we report on calculations of the magnetic behavior of a Dy2 cluster with the formula [hqH2][Dy2(hq)4(NO3)3].MeOH. The molecular complex contains one high symmetry Dy(III) ion and one low symmetry Dy(III) ion. Our calculations suggest that exchange coupling between the two ions controls the behavior of the magnetization at low temperature, while the crystal field of the low symmetry Dy(III) ion controls the behavior at higher temperature. A point charge electrostatic model, based on crystallographic coordinates, provides a starting point for the determination of the crystal field. Parameters in these calculations are adjusted to provide best fits to inelastic neutron scattering data (INS) and low temperature magnetometry: the INS measurements access crystal field energies and low temperature magnetization probes the Dy-Dy exchange interaction. Work supported by ARO W911NF-13-1-1025 (CCNY) and NSF-DMR-1309202 (NYU).

  19. 26 CFR 48.4082-1 - Diesel fuel and kerosene; exemption for dyed fuel.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Diesel fuel and kerosene; exemption for dyed..., Tread Rubber, and Taxable Fuel Taxable Fuel § 48.4082-1 Diesel fuel and kerosene; exemption for dyed... fuel or kerosene if— (1) The person otherwise liable for tax is a taxable fuel registrant; (2) In the...

  20. Large magneto-optical effect in low-temperature-grown GaDyN

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.K.; Emura, S.; Hasegawa, S.; Asahi, H. [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2011-07-15

    GaDyN layers were grown at temperatures at 300 C by radio-frequency plasma-assisted molecular-beam epitaxy on sapphire substrates. X-ray diffraction results showed no obvious secondary phase in the GaDyN samples. A sharp line was found at 582.4 nm in the photoluminescence spectra from the low-temperature-grown samples, which was assigned intra-4f orbital transition: {sup 4}F{sub 9/2} - {sup 6}H{sub 13/2} of Dy{sup 3+} ion. It was shown that Dy atoms were incorporated into the Ga sites in these GaDyN layers. Magnetic circular dichroism (MCD) measurement was performed for these samples at 10 K to investigate magneto-optical effect. It was found that the large magneto-optical effect in the GaDyN depend on the Dy concentration. It is the evidence of ferromagnetic s -f exchange coupling in the GaDyN, which enhance the Zeeman splitting. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Performance of Brazilian thermoluminescent CaSO{sub 4}: Dy pellets in standard diagnostic radiology beams

    Energy Technology Data Exchange (ETDEWEB)

    Maia, A.F.; Caldas, L.V.E. [Instituto de Pesquisas Energeticas e Nucleares, Comissao Nacional de Energia Nuclear, Av. Prof. LIneu Prestes, 2242 Sao Paulo (Brazil)]. e-mail: afmaia@ipen.br

    2006-07-01

    The high sensitivity of CaSO{sub 4}: Dy as a thermoluminescent material is a great advantage when dealing with low dose levels, as in diagnostic radiology procedures. However, these kinds of dosemeters present a high energy dependence that must be precisely determined in the energy range of interest. Dosimetric pellets of CaSO{sub 4}: Dy are produced at IPEN since the end of the 80 Th decade. These pellets are produced in three forms: conventional CaSO{sub 4}: Dy (50 mg); thin CaSO{sub 4}: Dy (20 mg) and CaSO{sub 4}: Dy + 10% C (20 mg). The main applications of these dosemeters are in personal and environmental dosimetry. In this study, CaSO{sub 4}: Dy pellets produced at IPEN were evaluated in diagnostic radiology standard beams. These qualities are based on the IEC 61267 standard, and they were established at an industrial X-ray system Pantak/Seifert, model ISOVOLT 160HS. Former studies evaluated CaSO{sub 4}: Dy of different origins in diagnostic beams. In this study, a large energy interval was used to include computed tomography energy beams. The results obtained show the behavior of the IPEN CaSO{sub 4}: Dy pellets in diagnostic standard beams. All results confirm that these pellets may be used for dosimetric procedures in diagnostic radiology beams. (Author)

  2. Luminescent characteristics of CaSO{sub 4}:Dy films obtained by spray pyrolysis method

    Energy Technology Data Exchange (ETDEWEB)

    Roman, J., E-mail: holand_jeos@hotmail.com [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria-IPN, Av. Legaria 694, Col. Irrigacion, Mexico, D.F. 11500 (Mexico); Rivera, T.; Lozano, I.B. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria-IPN, Av. Legaria 694, Col. Irrigacion, Mexico, D.F. 11500 (Mexico); Sosa, R. [Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco186, Col. Vicentina, Mexico, D.F., 09340 (Mexico); Alarcon, G. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria-IPN, Av. Legaria 694, Col. Irrigacion, Mexico, D.F. 11500 (Mexico)

    2012-07-15

    The present paper reports the experimental results of dysprosium doped calcium sulphate (CaSO{sub 4}:Dy) films deposited by spray pyrolysis method. CaSO{sub 4}:Dy films were deposited on three different surfaces: glass, aluminum and quartz substrates at temperatures in the range from 450 to 600 Degree-Sign C. Structural and morphological characteristics of CaSO{sub 4}:Dy films were observed. Thermoluminescent characteristics of films were determined by irradiating ultraviolet energy region. Thermoluminescent glow curve of CaSO{sub 4}:Dy films with glass and aluminum substrates showed a peak under environmental irradiation. Both TL response glow shape and intensity of CaSO{sub 4}:Dy films UV irradiated as a function of substrates were studied. - Highlights: Black-Right-Pointing-Pointer We carried out the preparation of calcium sulfate films doped with dysprosium (CaSO{sub 4}:Dy) by spray paralysis method. Black-Right-Pointing-Pointer SEM and EDS techniques were applied to study the surface topography and chemical composition of the CaSO{sub 4}:Dy films. Black-Right-Pointing-Pointer Thermoluminescent characteristics of films were determined by irradiating ultraviolet energy region. Black-Right-Pointing-Pointer The thermoluminescent response of CaSO{sub 4}:Dy films as a function of substrate was analyzed.

  3. Level statistics for the even-even Yb isotopes

    Institute of Scientific and Technical Information of China (English)

    CHEN Fang-Qi; SUN Yang; ZHOU Xian-Rong

    2009-01-01

    The level statistics of the even-even Yb isotopes are studied by using the energy levels calculated by the projected shell model. The spectrum of intrinsic states and band energies are also studied to discuss the generation of chaoticity. The energy dependence of the chaoticity is investigated, and a chaos to order transition is found.

  4. Coherent combining in an Yb doped double core fiber laser

    CERN Document Server

    Boullet, Johan; Desfarges-Berthelemot, Agnès; Kermène, Vincent; Pagnoux, Dominique; Roy, Philippe; Dussardier, Bernard; Blanc, Wilfried; 10.1364/OL.30.001962

    2012-01-01

    Coherent combining is demonstrated in a clad pumped Yb doped double core fiber laser. A slope efficiency of more than 70 % is achieved with 96 % of the total output power on the fundamental mode of one of the two cores. This high combining efficiency is obtained when both cores are coupled via a biconical fused taper in a Michelson interferometer configuration.

  5. Optical properties of epitaxial YAG:Yb films

    Energy Technology Data Exchange (ETDEWEB)

    Ubizskii, S.B. [Institute for Telecommunication, Radioelectronics and Electronic Engineering, Lviv Polytechnic National University, 12, Bandera St., Lviv, 79013 (Ukraine); Matkovskii, A.O. [Institute for Telecommunication, Radioelectronics and Electronic Engineering, Lviv Polytechnic National University, 12, Bandera St., Lviv, 79013 (Ukraine); Institute of Physics, University Rzezsow, 16 Rejtana St., Rzeszow, 35310 (Poland); Melnyk, S.S.; Syvorotka, I.M. [R and D Institute for Materials, Scientific Research Company ' ' Carat' ' , 202, Stryjska St., Lviv, 79031 (Ukraine); Mueller, V.; Peters, V.; Petermann, K. [Institut fuer Laser-Physik, Universitaet Hamburg, Jungiusstrasse 9a, 20355 Hamburg (Germany); Beyertt, A.; Giesen, A. [Institut fuer Strahlwerkzeuge, Universitaet Stuttgart, Pfaffenwaldring 43, 70569 Stuttgart (Germany)

    2004-03-01

    This work deals with the investigation of the optical properties of epitaxial YAG:Yb films and their suitability as gain media for thin disk lasers. Epitaxial films of YAG:Yb were grown by the liquid phase epitaxy method in air on the (111)-oriented YAG substrates. The thickness of the grown layers was from 30 to 260 {mu}m. The melt composition was varied to obtain the desired doping level from 10 to 15% and to optimize the optical properties. The best epitaxial films were colourless and had an Yb{sup 3+} luminescence lifetime of more than 950 {mu}s, which is very close to the intrinsic lifetime of the Yb ions in the bulk YAG single crystals. These films were tested in a thin disk laser setup with 24 absorption passes of the 940 nm pumping beam. The maximum output power at 1.03 {mu}m wavelength in CW operation reached more than 60 W and the optical efficiency was close to 30%. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Graphene Q-switched Yb:KYW planar waveguide laser

    NARCIS (Netherlands)

    Kim, Jun Wan; Choi, Sun Young; Aravazhi, Shanmugam; Pollnau, Markus; Griebner, Uwe; Petrov, Valentin; Bae, Sukang; Ahn, Kwang Jun; Yeom, Dong-Il; Rotermund, Fabian

    2015-01-01

    A diode-pumped Yb:KYW planar waveguide laser, single-mode Q-switched by evanescent-field interaction with graphene, is demonstrated for the first time. Few-layer graphene grown by chemical vapor deposition is transferred onto the top of a guiding layer, which initiates stable Q-switched operation in

  7. Electronic structure of Yb/H-Si (111) interface

    Institute of Scientific and Technical Information of China (English)

    Li Hong-Nian; Wang Xiao-Xiong; He Shao-Long; Zhang Han-Jie; Li Hai-Yang; Bao Shi-Ning

    2004-01-01

    Photoemission spectra are measured for Yb covered surface of wet-chemically-etched H-Si (111). The results reveal that the lattice structure of the H-Si (111) surface is stable against the deposition of Yb atoms. X-ray photoemission spectra indicate the formation of a polarized (dipole) surface layer, with the silicon negatively charged. Ultraviolet photoemission spectra exhibit the semiconducting property of the interface below one monolayer coverage. Work function variation during the formation of the Yb/H-Si (111) interface is measured by the secondary-electron cutoff in the ultraviolet photoemission spectral line. The largest decrease of work function is~1.65eV. The contributions of the dipole surface layer and the band bending to the work function change are determined to be~1.15eV and~0.5eV,respectively. The work function of metal Yb is determined to be~2.8040.05eV.

  8. Upconversion processes in Yb-sensitized Tm:ZBLAN

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

    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.

  9. Transition metal (Cr{sup 3+}) and rare earth (Eu{sup 3+}, Dy{sup 3+}) ions used as a spectroscopic probe in compositional-dependent lead borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Pisarski, W.A., E-mail: Wojciech.Pisarski@us.edu.p [University of Silesia, Institute of Chemistry, Szkolna 9, 40-007 Katowice (Poland); Pisarska, J. [Silesian University of Technology, Department of Materials Science, Krasinskiego 8, 40-019 Katowice (Poland); Dominiak-Dzik, G.; Ryba-Romanowski, W. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw (Poland)

    2009-09-18

    Compositional-dependent lead borate glasses doped with transition metal and rare earth ions were studied using absorption and luminescence spectroscopy. The trivalent Cr{sup 3+}, Eu{sup 3+} and Dy{sup 3+} ions were used as a spectroscopic probe in glass samples with various PbO/B{sub 2}O{sub 3} ratios. Spectral analysis indicates that Cr{sup 3+} ions occupy intermediate field sites; the both sites coexist and emit from the {sup 4}T{sub 2} (low-field) and the {sup 2}E (high-field) states, respectively. The R and Y/B values due to {sup 5}D{sub 0}-{sup 7}F{sub 2}/{sup 5}D{sub 0}-{sup 7}F{sub 1} and {sup 4}F{sub 9/2}-{sup 6}H{sub 15/2}/{sup 4}F{sub 9/2}-{sup 6}H{sub 13/2} luminescence intensity ratios of Eu{sup 3+} and Dy{sup 3+} ions, respectively, increase with increasing heavy metal (PbO) content, suggesting higher asymmetry and more covalent bonding character between rare earth and oxygen ions.

  10. Spectroscopic and energy transfer behavior of Dy3+ ions in B2O3sbnd TeO2sbnd PbOsbnd PbF2sbnd Bi2O3sbnd CdO glasses for laser and WLED applications

    Science.gov (United States)

    Arunkumar, S.; Venkataiah, G.; Marimuthu, K.

    2015-02-01

    A new series of white light emitting Dy3+ doped Lead tellurofluoroborate glasses have been prepared and their spectroscopic and energy transfer behavior were explored through analyzing XRD, FTIR, Raman, SEM, EDAX, optical absorption, photoluminescence and lifetime measurements. The fundamental stretching of the various borate and tellurite networks were identified using FTIR and Raman spectral analysis. The bonding parameter studies reveal the ionic nature of the Dysbnd O bond in the present glasses. The Judd-Ofelt (JO) intensity parameters determined from the absorption spectra have been used to investigate the nature of bonding and symmetry orientation of the Dy-ligand field environment. The luminescence intensity increases with increasing Dy3+ ion concentration up to 0.5 wt%, beyond that luminescence quenching is observed. The JO parameters have been used to determine the transition probability (A), stimulated emission cross-section (σPE), radiative lifetime (τR) and branching ratios (βR) for the different emission transitions from the 4F9/2 excited level. The higher σPE and βR values of the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions suggest the possible laser action in the visible region. The Y/B ratio, CIE chromaticity color coordinates (x, y) and Color correlated temperature (CCT) were also estimated from the luminescence spectra for different concentration as well as pumping wavelengths. The x, y chromaticity color coordinates fall within the white light region and the white light can be tuned by varying the excitation wavelengths. The lifetime of the 4F9/2 excited state were measured and is found to decrease with increasing Dy3+ ion content. The non-exponential behavior is predominant in higher Dy3+ ion content glasses and is due to the efficient energy transfer between Dy3+sbnd Dy3+ ions. The decay curves were fitted to the Inokuti-Hirayama (IH) model to understand the nature of energy transfer. Among the prepared glasses, 0.5DPTFB glass

  11. Dynamic parameters of Tb-Dy-Fe giant magnetostrictive alloy

    Institute of Scientific and Technical Information of China (English)

    白夏冰; 蒋成保

    2010-01-01

    Tb0.3Dy0.7Fe1.90 oriented rods were prepared by zone melting with unidirectional solidification.The magnetomechanical coupling factor(k33) was measured by magnetomechanical resonance under different DC bias fields up to 77.4 mT.An effective method was provided to calculate sonic velocity,elastic modulus and compliance constant through measuring resonate frequency(fr),and calculate dynamic magnetostriction(d33) via measuring magnetic permeability,magnetomechanical coupling factor(k33) and compliance co...

  12. Parametric models of reflectance spectra for dyed fabrics

    Science.gov (United States)

    Aiken, Daniel C.; Ramsey, Scott; Mayo, Troy; Lambrakos, Samuel G.; Peak, Joseph

    2016-05-01

    This study examines parametric modeling of NIR reflectivity spectra for dyed fabrics, which provides for both their inverse and direct modeling. The dye considered for prototype analysis is triarylamine dye. The fabrics considered are camouflage textiles characterized by color variations. The results of this study provide validation of the constructed parametric models, within reasonable error tolerances for practical applications, including NIR spectral characteristics in camouflage textiles, for purposes of simulating NIR spectra corresponding to various dye concentrations in host fabrics, and potentially to mixtures of dyes.

  13. Phase Transitions above the Yrast Line in {sup 154}Dy

    Energy Technology Data Exchange (ETDEWEB)

    Ma, W. C. [Mississippi State University, Mississippi State, Mississippi 39762 (United States); Martin, V. [Analisis Numerico, Facultad de Informatica, Universidad Politecnica de Madrid, E-28660 Madrid, (Spain); Khoo, T. L. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Lauritsen, T. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Egido, J. L. [Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, E-28049 Madrid, (Spain); Ahmad, I. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Bhattacharyya, P. [Purdue University, West Lafayette, Indiana 47907 (United States); Carpenter, M. P. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Daly, P. J. [Purdue University, West Lafayette, Indiana 47907 (United States); Grabowski, Z. W. [Purdue University, West Lafayette, Indiana 47907 (United States)] (and others)

    2000-06-26

    Spectra of the E2 quasicontinuum {gamma} rays feeding different spin regions of the {sup 154}Dy yrast line have been extracted. These are compared with corresponding theoretical spectra obtained by numerical simulations based on temperature-dependent Hartree-Fock theory, with thermal shape fluctuations. In this manner, different regions of the spin-energy plane can be examined. The results support the predictions of a smeared-out phase transition at high spin above the yrast line. (c) 2000 The American Physical Society.

  14. Quadrupole moments in chiral material DyFe3(BO3)4 observed by resonant x-ray diffraction

    Science.gov (United States)

    Nakajima, Hiroshi; Usui, Tomoyasu; Joly, Yves; Suzuki, Motohiro; Wakabayashi, Yusuke; Kimura, Tsuyoshi; Tanaka, Yoshikazu

    2016-04-01

    By means of circularly polarized x rays at the Dy L3 and Fe K absorption edges, the chiral structure of the electric quadrupole was investigated for a single crystal of DyFe3(BO3)4, in which both Dy and Fe ions exhibit a spiral arrangement. The integrated intensity of the resonant x-ray diffraction of space-group forbidden reflections 004 and 005 is interpreted within the electric dipole transitions from Dy 2 p3/2 to 5 d and Fe 1 s to 4 p , respectively. We have confirmed that the handedness of the crystal observed at Dy L3 and Fe K edges is consistent with that observed at Dy M5 edge reported in a previous study. The electric quadrupole moments of Dy 5 d and Fe 4 p are derived by analyzing the azimuth scans of the diffracted intensity. The temperature profiles of the integrated intensity of 004 at the Dy L3 and the Fe K edges are similar to those of Dy-O and Fe-O bond lengths, while the temperature dependence at the Dy M5 edge does not match the bond-length behavior. The results indicate that the helix chiral orientations of quadrupole moments due to Dy 5 d and Fe 4 p electrons are more strongly coupled to the ligands states than Dy 4 f electrons.

  15. Roles of Eu2+, Dy3+ Ions in Persistent Luminescence of Strontium Aluminates Phosphors

    Institute of Scientific and Technical Information of China (English)

    L(U) Xingdong; ZHONG Minjuan; WANG Renqin

    2008-01-01

    The polycrystalline Eu2+ and Dy3+ co-doped strontium aluminates SrAl2O4: Eu2+,Dy3+ with different compositions were prepared by solid state reactions. The UV-excited photoluminescence, persistent luminescence and thermo-luminescence were studied and compared. Results show that the doped Eu2+ ion in SrAl2O4: Eu2+, Dy3+phosphors works as not only the UV-excited luminescent center but also the persistent luminescent center. The doped Dy3+ ion can hardly yield any luminescence under UV-excitation, but effectively enhance the persistent luminescence and thermo-luminescence of SrAl2O4: Eu2+. Dy3+ co-doping can help form electron traps with appropriate depth due to its suitable electro-negativity, and increase the density and depth of electron traps. Based on above observations, a persistent luminescence mechanism, electron transfer model, is proposed and illustrated.

  16. Effects of Dy on cyclic oxidation resistance of NiAl alloy

    Institute of Scientific and Technical Information of China (English)

    GUO Hong-bo; WANG Xiao-yan; LI Ji; WANG Shi-xing; GONG Sheng-kai

    2009-01-01

    The NiAl alloys modified by reactive element(RE), dysprosium(Dy), were produced by arc melting. The microstructures of the modified alloys were investigated by field emission-scanning electron microscope(FE-SEM) equipped with energy dispersive spectroscope(EDS) and back scatter detector. Cyclic oxidation tests at 1 200 ℃ were conducted to assess the cyclic oxidation performance of the alloys. The Dy dopant prevents the surface rumpling of the oxide scale and the formation of cavities beneath the oxide scale. The pegs consisting of Dy-rich oxide inclusion core and an outer alumina sheath develop deeply in the alloy and improve the oxide scale adhesion. 0.05%-0.1% (molar fraction) Dy dramatically improves the cyclic oxidation resistance of the NiAl alloy. Too high concentration of Dy is deleterious because of the fast oxidation rate caused by severe internal oxidation.

  17. Photoluminescence and thermoluminescence studies of CaAl2O4:Dy(3+) phosphor.

    Science.gov (United States)

    Ziyauddin, Mohammad; Tigga, Shalinta; Brahme, Nameeta; Bisen, D P

    2016-02-01

    Calcium aluminate phosphors activated by Dy(3+) have been prepared by a combustion method at a temperature of 600°C. Photoluminescence (PL) and thermoluminescence (TL) properties of gamma-irradiated Dy-doped calcium aluminate were investigated. The PL spectrum shows a broad peak around 488 nm and 573 nm, under 347 nm excitation. Thermoluminescence studies were performed for different concentrations of Dy. Optimum intensity of photoluminescence was found for 0.02 mol% concentration of Dy. It was found that initially the peak TL intensity increases with increasing concentration of Dy in the CaAl2O4 host, attains a maximum value for 0.05 mol% concentration and decreases with further increase in the doping concentration due to concentration quenching. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Luminescence properties of Dy3+ doped lanthanum-calcium-silicaborate glass scintillator

    Science.gov (United States)

    Park, J. M.; Ha, D. H.; Lee, S. W.; Chanthima, N.; Ruangtaweep, Y.; Kaewkhao, J.

    2016-09-01

    In this research Dy3+-doped lanthanum-calcium-silicaborate glass scintillators, with the formula 25La2O3: 10CaO: 10SiO2: (55-x)B2O3: xDy2O3, were fabricated by using the melt-quenching technique. For the Dy3+ doping concentrations from 0.05 mol% to 0.5 mol% studied the luminescence properties of the Dy3+-doped glass scintillators with various radiation sources, such as X-ray, photo-, laser, and proton. To understand the absorption state, we measured the transmittance spectrum. Furthermore, X-ray, photo- and proton-induced emission spectra were measured to study the transition states of Dy3+-doped glass scintillators. The laser-induced emission spectra were measured at low temperatures in the range from 10 K to 300 K.

  19. Preparation of DyFe2 and TbFe2 by Reduction-Diffusion Process

    Institute of Scientific and Technical Information of China (English)

    Guangsi GUO; Guangtai WANG; Zhitong SUI

    2004-01-01

    The pure intermetallic compounds (Tb1-xDyx)Fe2 are super-magnetostriction materials, which were produced from DyFe2and TbFe2 in this paper. The thermodynamic possibility and kinetic feasible conditions for DyFe2 and TbFe2 preparation by reduction-diffusion in Ca-Dy2O3-Fe and Ca-Tb4O7-Fe systems were analyzed and the products of DyFe2 and TbFe2 were confirmed by XRD. The contracting core model was applied to describe the reduction-diffusion process in which the diffusion is a rate-controlled step. The apparent activation energies of DyFe2 and TbFe2 processes are 45 and 39 k J/mol respectively.

  20. DyP-type peroxidases comprise a novel heme peroxidase family.

    Science.gov (United States)

    Sugano, Y

    2009-04-01

    Dye-decolorizing peroxidase (DyP) is produced by a basidiomycete (Thanatephorus cucumeris Dec 1) and is a member of a novel heme peroxidase family (DyP-type peroxidase family) that appears to be distinct from general peroxidases. Thus far, 80 putative members of this family have been registered in the PeroxiBase database (http://peroxibase.isbsib.ch/) and more than 400 homologous proteins have been detected via PSI-BLAST search. Although few studies have characterized the function and structure of these proteins, they appear to be bifunctional enzymes with hydrolase or oxygenase, as well as typical peroxidase activities. DyP-type peroxidase family suggests an ancient root compared with other general peroxidases because of their widespread distribution in the living world. In this review, firstly, an outline of the characteristics of DyP from T. cucumeris is presented and then interesting characteristics of the DyP-type peroxidase family are discussed.

  1. Thermodynamic and Kinetic Study of Crystallization Reaction of Fe/Dy Multilayers Form Amorphous State

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To give further insight into the behavior of Fe/Dy multilayers in the crystallization from as-deposited amorphous state, free energy diagram of Fe/Dy system was constructed based on Miedema semiempirical theory. It is shown that the crystallization of amorphous films is controlled by both thermodynamic and kinetic conditions. The calculated free energies of crystalline Fe and Dy are significantly lower than those in the amorphous states, which provide thermodynamic driving force for crystallization. During annealing, the kinetic phase evolution of the multilayers is controlled by free energy barrier of nucleation and critical-size of new phase nucleus. Thus it explains the experimental results that Fe crystallites formed first followed by Dy grains, whereas crystalline Fe-Dy intermetallic compounds were not observed during annealing at moderate temperatures.

  2. Preparation of Dy-Bi alloy films by electrodeposition in organic bath

    Institute of Scientific and Technical Information of China (English)

    LI Gaoren; TONG Yexiang; LIU Guankun

    2004-01-01

    The cyclic voltammetry and potentiostatic electrolysis were used to investigate the preparing of Dy-Bi alloy films in LiCl-DMSO (dimethylsulfoxide) system. The effects of several factors including the potential of deposition, concentrations of main salts, and the concentration ratio of DyCl3 to Bi(NO3)3 were studied. Dy-Bi alloy films containing 4.82%-80.62% (mass fraction) dysprosium were prepared in DyCl3-Bi(NO3)3-LiCl-DMSO system by controlling the system composition and deposition conditions. The films are gray, uniform, metallic luster and adhere firmly to the copper substrates analyzed by SEM (scanning electron microscope), EDS (X-ray energy dispersive analysis), and XRD (X-ray diffraction). After heat treatment at 718 K for l h, the alloy phase of Dy-Bi was found in XRD patterns.

  3. Developments in the Gung Ho dynamical core

    Science.gov (United States)

    Melvin, Thomas

    2017-04-01

    Gung Ho is the new dynamical core being developed for the next generation Met Office weather and climate model, suitable for meeting the exascale challenge on emerging computer architectures. It builds upon the earlier collaborative project between the Met Office, NERC and STFC Daresbury of the same name to investigate suitable numerical methods for dynamical cores. A mixed-finite element approach is used, where different finite element spaces are used to represent various fields. This method provides a number of beneficial improvements over the current model, such a compatibility and inherent conservation on quasi-uniform unstructured meshes, whilst maintaining the accuracy and good dispersion properties of the staggered grid currently used. Furthermore, the mixed finite element approach allows a large degree of flexibility in the type of mesh, order of approximation and discretisation, providing a simple way to test alternative options to obtain the best model possible.

  4. Tessellation of SoHO Magnetograms

    Indian Academy of Sciences (India)

    R. Srikant; Jagdev Singh

    2000-09-01

    A gradient based algorithm which divides arbitrary images into non-overlapping surface filling tiles of opposite polarity is used to study the flux and size distributions of large scale magnetic flux concentrations in solar and heliospheric observatory (SoHO) magnetograms. The mean absolute flux and size of the concentrations at the considered scale is found to be about 1.7 × 1018Mx and 5.2Mm for both polarities. The form of the flux distribution is characterized by a skewness of 3 = 4.9 and a kurtosis of 4, = 42.8. The fall in the distribution in the range 6.5 × 1017Mx to 5 × 1018Mx is described by an exponential fit, in agreement with a model for the sustenance of quiet region flux.

  5. Marketing internetového obchodu

    OpenAIRE

    Popolanský, Jiří

    2010-01-01

    V mé diplomové práci se budu zabývat tématem marketingu internetového obchodu. V teoretické části se zaměřím na nalezení vhodných nástrojů marketingové podpory. V praktické části zejména na analýzu současné situace v konkrétním podniku a vlastní návrh marketingové kampaně pro daný internetový obchod. In my master’s thesis I will deal with theme marketing for e-business. In theoretic part I focus on finding useful instruments for marketing subvention. In practical part especially on analysi...

  6. Fabrication and Lasing Property of YbYb3+-doped Double-Clad Fibers with Novel Inner Cladding

    Institute of Scientific and Technical Information of China (English)

    Ding Ning; Yang Xiang; Zhaowen Xu; Wande Fan; Yongqing Yi; Shuzhong Yuan; Xiaoyi Dong

    2003-01-01

    The Yb3+-doped double-clad fibers with novel inner cladding have been made by using MCVD process, solution-doping method and optical machining together. The laser power and slope efficiency of the fiber lasers are higher than 1.8W and 50% respectively.

  7. 3,2-HOPO Complexes of Near-Infra-Red (NIR) Emitting Lanthanides: Sensitization of Ho(III) and Pr(III) in Aqueous Solution

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Evan G.; Szigethy, Geza; Xu, Jide; Palsson, Lars-Olof; Beeby, Andrew; Raymond, Kenneth N.

    2008-05-19

    There is a growing interest in Near Infra-Red (NIR) emission originating from organic complexes of Ln{sup III} cations. As a major impetus, biological tissues are considerably more transparent at these low energy wavelengths when compared to visible radiation, which facilitates deeper penetration of incident and emitted light. Furthermore, the long luminescence lifetimes of Ln{sup III} complexes (eg. Yb{sup III}, {tau}{sub rad} {approx} 1 ms) when compared to typical organic molecules can be utilized to vastly improve signal to noise ratios by employing time-gating techniques. While the improved quantum yield of Yb{sub III} complexes when compared to other NIR emitters favors their use for bioimaging applications, there has also been significant interest in the sensitized emission from other 4f metals such as Ln = Nd, Ho, Pr and Er which have well recognized applications as solid state laser materials (eg. Nd {approx} 1.06 {micro}m, Ho {approx} 2.09 {micro}m), and in telecommunications (eg. Er {approx} 1.54 {micro}m) where they can be used for amplification of optical signals. As a result of their weak (Laporte forbidden) f-f absorptions, the direct excitation of Ln{sup III} cations is inefficient, and sensitization of the metal emission is more effectively achieved using the so-called antenna effect. We have previously examined the properties of several Eu{sup III} complexes which feature 1-hydroxypyridin-2-one (Fig. 1) as the light harvesting chromophore. While the 1,2-HOPO isomer was found to strongly sensitize Eu{sup III}, we noted the analogous Me-3,2-HOPO isomer does not, which prompted further investigation of the properties of this chromophore with other metals.

  8. Positive feedback loop of YB-1 interacting with Smad2 promotes liver fibrosis.

    Science.gov (United States)

    Xiong, Panpan; Zhang, Jun; Xu, Diannan; Zhu, Jie; Li, Wenshuai; Liu, Jie; Liu, Fei

    2017-03-18

    Y-box binding protein (YB-1), known as a multifunctional cellular protein in various biological processes, was recently reported to be associated with liver fibrosis. The critical role of TGF-β/Smad signaling pathway in stimulating the transcription of fibrotic genes in fibroblasts have already been identified, however, whether and how YB-1 modulated liver fibrosis via TGF-β/Smad signaling pathway remains largely unknown. In our previous study, we proved that ectopic TGF-β was associated with YB-1 expression. Herein, by combining in vitro experiments in LX2 human hepatic stellate cells and in vivo studies by building CCl4 based mice liver fibrosis model, we showed that YB-1 and p-YB-1 were upregulated in liver fibrosis tissue, and YB-1 promoted the deposition of excess extracellular matrix. Mechanistically, Smad2, a key member in TGF-β signaling pathway, acted as a transcription factor that triggered YB-1 promoter, while on the other hand, p-YB-1 stabilized Smad2 by attenuating its ubiquitination. Knockdown of Smad2 could reduce YB-1 expression, which in turn shorter the half time of Smad2. Furthermore, the serine102 residue of YB-1 both affected its binding and stabilizing activity to Smad2. These finding demonstrated that YB-1 and Smad2 played as a positive feedback loop in promoting liver fibrosis. In conclusion, TGF-β signaling pathway may influence liver fibrosis by incorporating with YB-1, indicating that YB-1 could be a potential target for therapies against liver fibrosis.

  9. Apo A1 Mimetic Rescues the Diabetic Phenotype of HO-2 Knockout Mice via an Increase in HO-1 Adiponectin and LKBI Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Jian Cao

    2012-01-01

    Full Text Available Insulin resistance, with adipose tissue dysfunction, is one of the hallmarks of metabolic syndrome. We have reported a metabolic syndrome-like phenotype in heme oxygenase (HO-2 knockout mice, which presented with concurrent HO-1 deficiency and were amenable to rescue by an EET analog. Apo A-I mimetic peptides, such as L-4F, have been shown to induce HO-1 expression and decrease oxidative stress and adiposity. In this study we aimed to characterize alleviatory effects of HO-1 induction (if any on metabolic imbalance observed in HO-2 KO mice. In this regard, HO-2(−/− mice were injected with 2 mg/kg/day L-4F, or vehicle, i.p., for 6 weeks. As before, compared to WT animals, the HO-2 null mice were obese, displayed insulin resistance, and had elevated blood pressure. These changes were accompanied by enhanced tissue (hepatic oxidative stress along with attenuation of HO-1 expression and activity and reduced adiponectin, pAMPK, and LKB1 expression. Treatment with L-4F restored HO-1 expression and activity and increased adiponectin, LKB1, and pAMPK in the HO-2(−/− mice. These alterations resulted in a decrease in blood pressure, insulin resistance, blood glucose, and adiposity. Taken together, our results show that a deficient HO-1 response, in a state with reduced HO-2 basal levels, is accompanied by disruption of metabolic homeostasis which is successfully restored by an HO-1 inducer.

  10. Effects of Yb3+ codoping on visible and near infrared emissions of Er3+-Yb3+ codoped AI203 powders by the sol-sol method

    Institute of Scientific and Technical Information of China (English)

    DONG Bin; SUN Min; FENG ZhiOing; SONG ZhaoYuan; LIU XiaoDong

    2008-01-01

    The 0.1 mol% Er3+ and 0-2 mol% Yb3+ codoped AI2O3 powders were prepared by the sol-gel method, and the phase structure, including only two crystalline types of doped AI2O3 phase, γ-(AI,Er, Yb)2O3 andO-(AI,Er, Yb)2O3, was detected at the sintering temperature of 1000. The visible and near infrared emissions properties depended strongly on the Yb3+ codoping, and the corresponding maximal peak intensities centered at about 523, 545, 660 and 1533 nm were obtained respectively for the 0.1 mol% Er3+ and 0.5 mol% Yb3+ codoped AI2O3 powders, which were composed of 0-(AI,Er, Yb)O3 and a smallamount of γ-(AI,Er, Yb)2O3 phases. The two-photon absorption process was responsible for the visible up-conversion emissions, and the one-photon absorption process was involved in the near infrared emissions of the Er3+-Yb3+ codoped AI2O3 powders.

  11. Activation cross sections of the {sup nat}Yb(p,xn){sup 169}Lu reaction for indirect production of the therapeutic radionuclide {sup 169}Yb

    Energy Technology Data Exchange (ETDEWEB)

    Tarkanyi, F. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), 4026 Debrecen, Bem ter 18/c (Hungary); Hermanne, A. [Cyclotron Laboratory, Vrije Universiteit Brussel (VUB), 1090 Brussels (Belgium); Takacs, S.; Ditroi, F. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), 4026 Debrecen, Bem ter 18/c (Hungary); Kiraly, B. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), 4026 Debrecen, Bem ter 18/c (Hungary)], E-mail: kiralyb@atomki.hu; Yamazaki, H.; Baba, M.; Mohammadi, A. [Cyclotron and Radioisotope Center (CYRIC), Tohoku University, Sendai 980-8578 (Japan); Ignatyuk, A.V. [Institute of Physics and Power Engineering (IPPE), Obninsk 249020 (Russian Federation)

    2009-09-01

    Activation cross sections of the {sup nat}Yb(p,xn){sup 169}Lu reaction have been measured for the first time up to 70 MeV to investigate the production possibility of the radionuclide {sup 169}Yb through decay of its parent {sup 169}Lu. The cross sections were measured using the stacked foil irradiation technique and gamma spectrometry. The experimental data were compared with the results of the ALICE-IPPE theoretical model code. Different production routes were compared for the internal radiotherapy related radioisotope {sup 169}Yb. Above 30 MeV proton energy the integral yield of the {sup nat}Yb(p,xn){sup 169}Lu reaction is higher than that of the earlier investigated {sup 169}Tm(p,n){sup 169}Yb, {sup 169}Tm(d,2n){sup 169}Yb, {sup nat}Er({alpha},xn){sup 169}Yb, {sup nat}Yb({alpha},x){sup 169}Lu and {sup nat}Hf(p,x){sup 169}Lu reactions at the equivalent particle energies.

  12. YB-1 overexpression promotes a TGF-β1-induced epithelial–mesenchymal transition via Akt activation

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Bin; Lee, Eun Byul; Cui, Jun; Kim, Yosup [Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 406-799 (Korea, Republic of); Jang, Ho Hee, E-mail: hhjang@gachon.ac.kr [Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 406-799 (Korea, Republic of); Gachon Medical Research Institute, Gil Medical Center, Gachon University, Incheon (Korea, Republic of)

    2015-03-06

    The Y-box binding protein-1 (YB-1) is a transcription/translation regulatory protein, and the expression thereof is associated with cancer aggressiveness. In the present study, we explored the regulatory effects of YB-1 during the transforming growth factor-β1 (TGF-β1)-induced epithelial-to-mesenchymal transition (EMT) in lung adenocarcinoma cells. Downregulation of YB-1 increased E-cadherin promoter activity, and upregulation of YB-1 decreased promoter activity, suggesting that the YB-1 level may be correlated with the EMT. TGF-β1 induced YB-1 expression, and TGF-β1 translocated cytosolic YB-1 into the nucleus. YB-1 overexpression promoted TGF-β1-induced downregulation of epithelial markers, upregulation of mesenchymal markers, and cell migration. Moreover, YB-1 overexpression enhanced the expression of E-cadherin transcriptional repressors via TGF-β1-induced Akt activation. Our findings afford new insights into the role played by YB-1 in the TGF-β1 signaling pathway. - Highlights: • YB-1 regulates E-cadherin expression in A549 cells. • TGF-β1 induces upregulating and nuclear localization of YB-1. • YB-1 overexpression accelerates TGF-β1-induced EMT and cell migration. • YB-1 regulates Snail and Slug expression via Akt activation.

  13. Synthesis of Multicolor Core/Shell NaLuF₄:Yb(3+)/Ln(3+)@CaF₂ Upconversion Nanocrystals.

    Science.gov (United States)

    Li, Hui; Hao, Shuwei; Yang, Chunhui; Chen, Guanying

    2017-02-07

    The ability to synthesize high-quality hierarchical core/shell nanocrystals from an efficient host lattice is important to realize efficacious photon upconversion for applications ranging from bioimaging to solar cells. Here, we describe a strategy to fabricate multicolor core @ shell α-NaLuF₄:Yb(3+)/Ln(3+)@CaF₂ (Ln = Er, Ho, Tm) upconversion nanocrystals (UCNCs) based on the newly established host lattice of sodium lutetium fluoride (NaLuF₄). We exploited the liquid-solid-solution method to synthesize the NaLuF₄ core of pure cubic phase and the thermal decomposition approach to expitaxially grow the calcium fluoride (CaF₂) shell onto the core UCNCs, yielding cubic core/shell nanocrystals with a size of 15.6 ± 1.2 nm (the core ~9 ± 0.9 nm, the shell ~3.3 ± 0.3 nm). We showed that those core/shell UCNCs could emit activator-defined multicolor emissions up to about 772 times more efficient than the core nanocrystals due to effective suppression of surface-related quenching effects. Our results provide a new paradigm on heterogeneous core/shell structure for enhanced multicolor upconversion photoluminescence from colloidal nanocrystals.

  14. Teoretické modely elektrického oblouku

    OpenAIRE

    Vondrák, Michal

    2015-01-01

    Tato práce se zabývá teoretickými modely elektrického oblouku. Vysvětlením pojmů plazmatu, elektrického oblouku a plazmatronů. Popsáním základního modelování elektrických oblouků. Popisem nepřímé metody pro stanovení střední teploty a rychlosti plazmajetu na výstupu z plazmatronu. Popisem zjednodušeného modelu s axiálně chlazeným elektrickým obloukem. This thesis deals with theoretical models of the electric arc. Plasma arc and plasma torch are explained. Basic approaches of electric arc m...

  15. Yellow laser performance of Dy$^{3+}$ in co-doped Dy,Tb:LiLuF$_4$

    CERN Document Server

    Bolognesi, Giacomo; Calonico, Davide; Costanzo, Giovanni Antonio; Levi, Filippo; Metz, Philip Werner; Kränkel, Christian; Huber, Günter; Tonelli, Mauro

    2015-01-01

    We present laser results obtained from a Dy$^{3+}$-Tb$^{3+}$ co-doped LiLuF$_{4}$ crystal, pumped by a blue emitting InGaN laser diode, aiming for the generation of a compact 578 nm source. We exploit the yellow Dy$^{3+}$ transition $^{4}$F$_{9/2}$ $\\Longrightarrow$ $^{6}$H$_{13/2}$ to generate yellow laser emission. The lifetime of the lower laser level is quenched via energy transfer to co-doped Tb$^{3+}$ ions in the fluoride crystal. We report the growth technique, spectroscopic study and room temperature continuous wave (cw) laser results in a hemispherical cavity at 574 nm and with a highly reflective output coupler at 578 nm. A yellow laser at 578 nm is very relevant for metrological applications, in particular for pumping of the forbidden $^{1}$S$_{0} \\Longrightarrow ^{3}$P$_{0}$ Ytterbium clock transition, which is recommended as a secondary representation of the second in the international system (SI) of units. This paper was published in Optics Letters and is made available as an electronic reprint ...

  16. Neutron scattering study on R{sub 2}PdSi{sub 3} (R=Ho,Er,Tm) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Fei

    2010-12-14

    Previous studies on the family of inter-metallic rare-earth compounds R{sub 2}PdSi{sub 3} revealed multifaceted magnetic properties, for instance, spin-glass like behavior. Experimental observations include: Signs of a crystallographic superstructure, complicated magnetic structures both in zero field and in applied magnetic fields as well as a generic phase in applied fields for compounds in the series with the heavy rare-earths R=Gd, Tb, Dy, Ho, Er and Tm. This thesis expands the studies on the magnetic properties of R{sub 2}PdSi{sub 3} employing mainly neutron scattering on single crystals with the focus on the compounds with R=Ho, Er and Tm. A detailed analysis of the crystallographic superstructure using modulation wave approach and group theory is presented. The resulting structure implies the existence of two different rare-earth sites with reduced symmetry and an arrangement of the different sites according to sequences as determined by the superstructure. It is shown that the reduced symmetry of the rare-earth sites is explicitly observed in the energy spectra of inelastic neutron scattering. The results on the magnetic structures and excitations are shown and discussed in the framework of the superstructure model. Specifically the generic phase in applied fields is interpreted as a direct consequence of the crystallographic superstructure. It is rather unusual that a crystallographic superstructure is playing such a decisive, and through the field dependence also tunable role in determining the magnetic properties as observed in R{sub 2}PdSi{sub 3}. The mediating interactions between the crystallographic part and the magnetic part of the system are discussed. (orig.)

  17. Dy(III)离子在LiCl-KCl熔盐中的电化学行为及Dy-Ni金属间化合物的选择性制备%Electrochemical Behavior of Dy(III) and the Selective Formation of Dy-Ni Intermetallic Compounds in LiCl-KCl Eutectic Melts

    Institute of Scientific and Technical Information of China (English)

    李梅; 孙婷婷; 刘斌; 韩伟; 孙扬; 张密林

    2015-01-01

    The electrochemical behavior of Dy(III) in LiCl-KCl melts and the al oying mechanism of Dy-Ni al oys were investigated by cyclic voltammetry, square wave voltammetry, and open circuit chronopotentiometry. Cyclic voltammetry and square wave voltammetry experiments indicated that the reduction of Dy(III) ions to Dy metal occurred in a single step with the exchange of three electrons. Compared with cyclic voltammograms on an inert W electrode, three reduction peaks are observed. This indicates the under-potential deposition of Dy(III) on a reactive Ni electrode because of the formation of Dy-Ni al oy compounds. Dy-Ni al oys were prepared by potentiostatic electrolysis at-1.6,-1.8, and-2.0 V and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). The results confirm that different Dy-Ni compounds:DyNi5, Dy2Ni7, and DyNi2 can be selectively obtained by potentiostatic electrolysis at different potentials.%采用循环伏安、方波伏安和开路计时电位等电化学方法研究了Dy(III)离子在LiCl-KCl共晶盐中的电化学行为及Dy-Ni合金形成的电化学机理.循环伏安和方波伏安法研究表明, Dy(III)离子的电化学还原过程为三个电子转移的一步反应.与惰性W电极相比, Dy(III)离子在Ni电极上的循环伏安曲线多出了三对氧化还原峰,是由于Dy与Ni形成了合金化合物,导致Dy(III)离子在活性Ni电极发生了欠电位沉积.采用X射线衍射(XRD)和扫描电子显微镜(SEM)附带能量散射谱(EDS)对恒电位(-1.6,-1.8和-2.0 V)电解制备的Dy-Ni合金进行分析,分别获得了DyNi5, Dy2Ni7和DyNi2金属间化合物.实验结果表明,通过控制电位进行恒电位电解可以有选择性地制备不同的金属间化合物.

  18. Uptake of HO2 Radicals Onto Dust Aerosols

    Science.gov (United States)

    Matthews, P. S.; Whalley, L. K.; Baeza-Romero, M. T.; Heard, D. E.

    2013-12-01

    OH and HO2 radicals play an important role in the troposphere by controlling its oxidative capacity and therefore the concentration of many trace species. Several field studies have observed significantly lower concentrations of HO2 radicals than predicted using box models (1,2). HO2 loss onto aerosols has been suggested as a possible sink. Mineral dust has an estimated annual flux of 2000 Tg year-1 (3). However, there has only been one study of HO2 uptake onto Arizona Test Dust (ATD) surfaces (4) and there are currently no published studies for dust aerosols. Therefore, the aim of this study was to measure the HO2 uptake coefficient onto ATD aerosols over a range of humidities and for different HO2 concentrations, as well as investigating the uptake as a function of the exposure time to the aerosol, for which a dependence had been observed for aqueous salt aerosols (5). Uptake coefficients were measured for ATD aerosols at atmospheric pressure and at 291 K using a Fluorescence Assay by Gas Expansion (FAGE) detector combined with a flow tube. HO2 was formed from the photolysis of water vapour and was injected into the flow tube using a moveable injector, which was placed in six different positions along the flow tube. The non stable aerosol output was produced by stirring ATD in a bottle producing a dust cloud which was entrained into a flow. The aerosol number concentration was measured using a Condensation Particle Counter (CPC) and was converted into a surface area using the average radius of one aerosol. The uptake coefficient was then able to be calculated by assuming first order kinetics. The HO2 uptake coefficient was measured at a relative humidity of between 6 and 75% and at initial HO2 concentrations of ~ 0.3 - 1 × 10^9 molecule cm-3. Average uptake coefficients of 0.018 × 0.006 and 0.031 × 0.008 were measured for the higher and lower HO2 concentrations respectively, and the impact investigated using a constrained box model. A time dependence was also

  19. Antireflective downconversion ZnO:Er3+,Yb3+ thin film for Si solar cell applications

    Science.gov (United States)

    Elleuch, R.; Salhi, R.; Deschanvres, J.-L.; Maalej, R.

    2015-02-01

    Hexagonal wurtzite phased ZnO:Er3+/Yb3+ thin films with various Yb concentrations were deposited on Si(111) substrate by Aerosol Assisted Chemical Vapor Deposition process. Post-annealed films at 1000 °C in air atmosphere showed a crystallinity enhancement. Yb3+ (4F7/2 → 4F5/2) 1000 nm emission increased with the increase of Yb3+ concentration emanating from an Er-Yb energy transfer. The reflectance percentage of 12% was achieved in the [250-1000 nm] range, and the refractive index of 1.97 was obtained for 632 nm wavelength. These results suggest that the (3 mol. % Er, 9 mol. % Yb) codoped film is a highly efficient antireflective downconversion layer for enhancing Si solar cell efficiency.

  20. The relationship between viscosity and glass forming ability of Al-(Ni)-Yb alloy systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The dynamic viscosity of Al-Yb and Al-Ni-Yb superheated melts was measured using a torsional oscillation viscometer. The results show that the temperature dependence of viscosity fits the Arrhenius law well and the fitting factors are calculated. The amorphous ribbons of these alloys were produced by the melt spinning technique and the thermal properties were characterized by using a differential scanning calorimetry (DSC). E (the activation energy for viscous flow), which reflects the change rate of viscosity, has a good negative relation with the GFA in both Al-Yb and Al-Ni-Yb systems. However, there is no direct relation between liquidus viscosity (ηL) and GFA. The superheated fragility M can predict GFA in Al-Yb or Al-Ni-Yb alloy system.

  1. Thermal Stability and Spectroscopic Properties of Yb3+-Doped New Gallium-Lead-Germanate Glass

    Institute of Scientific and Technical Information of China (English)

    XU Shi-Qing; FENG Ai-Ming; ZHANG Li-Yan; ZHAO Shi-Long; WANG Bao-Ling; ZHANG Jue; WANG Wei; BAO Ren-Qiang

    2006-01-01

    @@ Yb3+-doped new gallium-lead-germanate glass is presented. Thermal stability, spectroscopic and laser performance parameters of the Yb3+-doped new gallium-lead-germanate glass are calculated. The results show that the Yb3+-doped new gallium-lead-germanate glass has good thermal stability (△T = 198 ℃), high stimulated emission cross section (0.79pm2), and long fluorescence lifetime (1.46ms). Compared with other Yb3+-doped glass hosts, the Yb3+-doped new gallium-lead-germanate glass has better laser performance parameters and laser properties, indicating that Yb3+-doped new gallium-lead-germanate glass is a promising laser material for short pulse generation in diode pumped lasers, short pulse generation tunable laser, high-peak power and high-average power lasers.

  2. Faraday effect improvement by Dy{sup 3+}-doping of terbium gallium garnet single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhe, E-mail: zhenzhe1201@sina.com; Yang, Lei; Hang, Yin; Wang, Xiangyong

    2016-01-15

    Highly transparent Dy{sup 3+}-doped terbium gallium garnet (TGG) single crystal was grown by Czochralski (Cz) method. Phase composition of the crystal was tested by XRD measurements. The distribution coefficient of Dy{sup 3+} in the crystal was obtained. The optical and magneto-optical properties were analyzed in detail, and magnetic properties of the Dy{sup 3+}-TGG crystal were studied. The paramagnetic behavior is observed down to 10 K. The as-grown crystal exhibited high optical transmittance, particularly in the visible region. The Faraday rotation was investigated over visible and near-infrared regions (VIS–NIR) at room temperature. The Verdet constants increase at measured wavelengths and high thermal stability was found in Dy{sup 3+}-doped TGG, as compared to the properties of pure TGG, indicating that Dy{sup 3+}-doped crystals are preferable for magneto-active materials used in Faraday devices at VIS–NIR wavelengths. - Graphical abstract: Highly transparent Dy{sup 3+}-doped terbium gallium garnet (TGG) and pure TGG single crystals were grown by Czochralski method. The Dy{sup 3+}-doped TGG possesses 20–30% higher Verdet values in reference to TGG independently on wavelength.

  3. Temperature and magnetic field induced multiple magnetic transitions in DyAg(2).

    Science.gov (United States)

    Arora, Parul; Chattopadhyay, M K; Sharath Chandra, L S; Sharma, V K; Roy, S B

    2011-02-09

    The magnetic properties of the rare-earth intermetallic compound DyAg(2) are studied in detail with the help of magnetization and heat capacity measurements. It is shown that the multiple magnetic phase transitions can be induced in DyAg(2) both by temperature and magnetic field. The detailed magnetic phase diagram of DyAg(2) is determined experimentally. It was already known that DyAg(2) undergoes an incommensurate to commensurate antiferromagnetic phase transition close to 10 K. The present experimental results highlight the first order nature of this phase transition, and show that this transition can be induced by magnetic field as well. It is further shown that another isothermal magnetic field induced transition or metamagnetic transition exhibited by DyAg(2) at still lower temperatures is also of first order nature. The multiple magnetic phase transitions in DyAg(2) give rise to large peaks in the temperature dependence of the heat capacity below 17 K, which indicates its potential as a magnetic regenerator material for cryocooler related applications. In addition it is found that because of the presence of the temperature and field induced magnetic phase transitions, and because of short range magnetic correlations deep inside the paramagnetic regime, DyAg(2) exhibits a fairly large magnetocaloric effect over a wide temperature window, e.g., between 10 and 60 K.

  4. Dy3+ doped Lithium Sodium Bismuth Borate Glasses for Yellow Luminescent Photonic Applications

    Directory of Open Access Journals (Sweden)

    M. Parandamaiah,

    2015-08-01

    Full Text Available Lithium sodium bismuth borate glasses-doped with trivalent dysprosium (Dy3+ ions (LSBiB have been prepared by conventional melt-quenching technique and characterized by structural, thermal and spectroscopic measurements. XRD pattern of the host glass confirms its amorphous nature. Morphological and elemental analysis has also been carried out for Dy3+doped LSBiB glass matrix. FTIR spectral analysis confirms the glass formation of the host glass. Optical absorption spectral analysis has been carried out for 0.8 mol% Dy3+ doped LSBiB glass sample. Well defined optical absorption bands are assigned with corresponding electronic transitions. Photoluminescence spectra shows two prominent emission bands centered at 482 nm and 575 nm corresponds to the 4 F9/2 → 6H15/2 and 4 F9/2 → 6H13/2 respectively under the excitation of 452 nm. Among all the concentrations of Dy3+ ions, at 0.8 mol% Dy3+ contained glass sample exhibits prominent yellow emission at 575 nm. Lifetime decay dynamics have been systematically analyzed for all the glasses, higher lifetime is found to be 0.47 ms for 0.8 mol% Dy3+ ions doped glass. From the photoluminescence analysis, Dy3+ contained glass samples could be suggested as potential yellow luminescent glass matrix for several photonic device applications.

  5. Ho:YAG Single Crystal Fiber: Fabrication and Optical Characterization

    Science.gov (United States)

    2014-06-16

    diameter variations, two feedback systems are employed. First, a standard proportional-integral-derivative ( PID ) controller provides feedback from...broad emission band from 2050 – 2150 nm, and previous papers confirm the wavelength tuning capability of Ho:YAG solid state lasers [23]. Ho:YAG SCF... tuned across the spectral band, then the gain was measured and plotted as markers in Fig. 4 for the 10.5 cm piece, along with the measured emission

  6. Studies of sintered MRE-Fe-B magnets by DyF3 addition or diffusion treatment (MRE = Nd + Y + Dy)

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Wei; Dennis, Kevin W.; Kramer, Matthew; Anderson, Iver, McCallum, Ralph W.

    2012-03-13

    Sintered MRE2(Fe, Co)14B magnets by DyF3 blending or diffusion treatment were investigated. “Base-line” magnets with a thickness of 1.5 mm were coated (painted) with DyF3 powder and heated to promote Dy diffusion at 800–900 °C, i.e., “Diffusion” magnets. For comparison, the magnet alloy powder for making Base-line magnets was blended with 3–5 wt.% DyF3 powder and then made into sintered magnets, i.e., “Blended” magnets. The coercivity and (BH)max of Base-line magnets were 9.7 kOe and 32.7 MGOe, respectively, while the coercivity of Diffusion magnets was increased to 15 kOe and the (BH)max was nearly unchanged at 31.4 MGOe. Blended magnets with 5 wt% DyF3 had a coercivity of 17.8 kOe, but the (BH)max was reduced to 25.4 MGOe, due to a considerable reduction of remanence. The total Dy concentration in the MRE2(Fe, Co)14B Diffusion magnets with a β value of −0.5%/°C was 5.3 wt%, while typical commercial Nd-based Nd2Fe14B magnets require at least 7.5 wt% Dy to achieve the same β. Therefore, the MRE2(Fe, Co)14B Diffusion magnets exhibited better temperature stability.

  7. The green light generation by self-frequency-doubled Yb:YCOB crystal

    CERN Document Server

    Fang, Qiannan; Zhang, Huaijin; Wang, Jiyang

    2016-01-01

    Taking advantages of the broad emission bands of a Yb3+ doped calcium yttrium oxoborate (Yb:YCOB) crystal cut along the optimized direction out of principle planes with the maximum effective nonlinear coefficient, the self-frequency-doubled green light based on the self-frequency-doubling behavior of Yb:YCOB was achieved with a maximum output power of 710 mW at 523 nm.

  8. Links between the oncoprotein YB-1 and small non-coding RNAs in breast cancer.

    Directory of Open Access Journals (Sweden)

    Cherie Blenkiron

    Full Text Available BACKGROUND: The nucleic acid-binding protein YB-1, a member of the cold-shock domain protein family, has been implicated in the progression of breast cancer and is associated with poor patient survival. YB-1 has sequence similarity to LIN28, another cold-shock protein family member, which has a role in the regulation of small noncoding RNAs (sncRNAs including microRNAs (miRNAs. Therefore, to investigate whether there is an association between YB-1 and sncRNAs in breast cancer, we investigated whether sncRNAs were bound by YB-1 in two breast cancer cell lines (luminal A-like and basal cell-like, and whether the abundance of sncRNAs and mRNAs changed in response to experimental reduction of YB-1 expression. RESULTS: RNA-immunoprecipitation with an anti-YB-1 antibody showed that several sncRNAs are bound by YB-1. Some of these were bound by YB-1 in both breast cancer cell lines; others were cell-line specific. The small RNAs bound by YB-1 were derived from various sncRNA families including miRNAs such as let-7 and miR-320, transfer RNAs, ribosomal RNAs and small nucleolar RNAs (snoRNA. Reducing YB-1 expression altered the abundance of a number of transcripts encoding miRNA biogenesis and processing proteins but did not alter the abundance of mature or precursor miRNAs. CONCLUSIONS: YB-1 binds to specific miRNAs, snoRNAs and tRNA-derived fragments and appears to regulate the expression of miRNA biogenesis and processing machinery. We propose that some of the oncogenic effects of YB-1 in breast cancer may be mediated through its interactions with sncRNAs.

  9. Ytterbium Doped Gadolinium Oxide (Gd2O3:Yb3+) Phosphor: Topology, Morphology, and Luminescence Behaviour

    OpenAIRE

    Raunak Kumar Tamrakar; Durga Prasad Bisen; Chandra Shekher Robinson; Ishwar Prasad Sahu; Nameeta Brahme

    2014-01-01

    Gd2O3:Yb3+ phosphor has been synthesized by the solid state reaction method with boric acid used as a flux. The resulting Gd2O3:Yb3+ phosphor was characterized by X-ray diffraction (XRD) technique, Fourier transmission infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscope (TEM), and photoluminescence and thermoluminescence. The results of the XRD show that obtained Gd2O3:Yb3+ phosphor has a cubic structure. The average crystallite sizes could...

  10. p-Wave cold collisions in a Yb lattice clock

    CERN Document Server

    Lemke, N D; von Stecher, J; Sherman, J A; Rey, A M; Oates, C W

    2011-01-01

    State-of-the-art optical clocks with neutral atoms employ an optical lattice to tightly confine the atoms, enabling high-resolution spectroscopy and the potential for high-accuracy timekeeping. Interrogating many atoms simultaneously facilitates high measurement precision, but also yields high atomic density and the potential for cold collisions. To suppress these atom-atom interactions, the use of ultracold, spin-polarized fermions was proposed to exploit the Fermi suppression of s-wave collisions while freezing out higher-wave contributions. However, small collision shifts have been measured in Sr and Yb. For Sr, the shifts were attributed to s-wave interactions enabled by excitation inhomogeneity. Here, we report definitive experimental evidence and a quantitative theoretical treatment of p-wave collisions in Yb. We also demonstrate a novel suppression of the collisional frequency shift utilizing strong interactions in a two-dimensional optical lattice. Understanding these interactions and dynamics for two...

  11. Optical characterization of CdSe/Dy3+-doped silica matrices

    Indian Academy of Sciences (India)

    P V Jyothy; P R Rejikumar; Thomas Vinoy; S Kartika; N V Unnikrishnan

    2010-11-01

    Cadmium selenide nanocrystals along with dysprosium ions are doped in silica matrices through sol–gel route. The optical bandgap and size of the CdSe nanocrystals are calculated from the absorption spectrum. The size of the CdSe nanocrystallites is also evaluated from the TEM measurements. The fluorescence intensities are compared for SiO2–Dy3+ and CdSe-doped SiO2–Dy3+. The fluorescence intensity of Dy3+ is considerably increased in the presence of CdSe nanocrystals.

  12. Impact of high and zero formaldehyde crosslinkers on the performance of the dyed cotton fabric

    Directory of Open Access Journals (Sweden)

    Mohsin Muhammad

    2014-01-01

    Full Text Available Performance of the colored cotton fabrics dyed with sulphur, vat, direct and reactive dyes was investigated by using two crosslinkers. DMDHEU was used as formaldehyde based crosslinker and BTCA was assessed as a zero formaldehyde alternative. Shade change of the fabrics treated with both crosslinkers was comparable and in acceptable range apart from all sulphur dyes and two reactive dyes. However, shade change of the sulphur dyed fabrics was significantly improved when typical sodium hypophosphite based catalyst for BTCA was replaced with sodium phosphate. In addition, tensile strength and easy care performance of the crosslinker treated dyed fabric was also assessed.

  13. The melting diagram of the Ti-Dy-Sn system below 40 at.% Sn

    Energy Technology Data Exchange (ETDEWEB)

    Fartushna, Y.; Meleshevich, K.; Samelyuk, A.; Bulanova, M. [Frantsevich Inst. for Problems of Materials Science of NASU, Kiev (Ukraine)

    2010-10-15

    Phase equilibria in the Ti-Dy-Sn system below 40 at.% Sn were studied using differential thermal analysis, X-ray diffraction, metallography and electron microprobe. The partial liquidus and solidus projections and the melting diagram (liquidus + solidus) were constructed. A new ternary compound {tau} with composition Ti{sub 4.2-4.3}Dy{sub 0.8-0.7}Sn{sub {approx_lt}3}, found by us previously, melts congruently above 1543 C and coexists with all the phases based on the binary compounds of the boundary binaries in the concentration interval studied. The liquidus surface is characterized by primary crystallization regions of ({beta}Ti), ({beta}Dy), ({alpha}Dy), (Ti{sub 3}Sn), (Ti{sub 2}Sn), (Ti{sub 5}Sn{sub 3}), (Dy{sub 5}Sn{sub 3}) and {tau}. Five three-phase fields in the solidus surface result from three eutectic and two transition type invariant four-phase equilibria: L{sub E{sub 1}} {r_reversible} ({beta}Ti) + (Ti{sub 3}Sn) + (Dy{sub 5}Sn{sub 3}), L{sub E{sub 2}} {r_reversible} (Ti{sub 3}Sn) + {tau} + (Dy{sub 5}Sn{sub 3}), L{sub E{sub 3}} {r_reversible} ({beta}Ti) + ({alpha}Dy) + (Dy{sub 5}Sn{sub 3}), L{sub U{sub 1}} + (Ti{sub 2}Sn) {r_reversible} (Ti{sub 3}Sn) + {tau} and L{sub U{sub 2}} + (Ti{sub 2}Sn) {r_reversible} (Ti{sub 5}Sn{sub 3}) + {tau} at 1524, 1500, 1150, 1543 and 1498 C, respectively. In the two-phase areas ({beta}Ti) + (Dy{sub 5}Sn{sub 3}),(Ti{sub 3}Sn) + (Dy{sub 5}Sn{sub 3}), (Ti{sub 2}Sn) + {tau} and {tau} + (Dy{sub 5}Sn{sub 3}) the solidus surface has the temperature maxima at 1620, 1540, > 1543 and > 1500 C, respectively. (orig.)

  14. A microscopic study of deformation systematics in 154−166Dy isotopes

    Indian Academy of Sciences (India)

    Amita Dua; Arun Bharti; S K Khosa

    2007-06-01

    The Hartree–Bogoliubov (HB) framework of calculations has been applied for calculating various nuclear structure quantities for 154−166Dy mass chains. In this framework, the intrinsic quadrupole moments, the low-lying yrast states ($E_{2}^{+}$ and $E_{4}^{+}$) and occupation numbers for various shell model orbits have been obtained. The calculated results indicate that the observed onset of deformation in going from 154Dy to 166Dy arises due to enhanced occupation of (ℎ11/2) orbit, increased polarization of (5/2) orbit and increase in the occupation of down-slopping `' components of (13/2) and (ℎ9/2)υ orbits.

  15. A STUDY OF MULTI-GENE EXPRESSION IN THE HIGHLY METASTASIZING HUMAN OVARIAN CANCER CELL LINE HO-8910PM AND ITS MOTHER CELL LINE HO-8910

    Institute of Scientific and Technical Information of China (English)

    Ni Xinghao; Xu Shenhua; Wu Xiongwei; Zhang Gu; Qian Lijuan; Gao Yongliang

    1998-01-01

    Objective: To investigate multi-gene expression in the highly metastasizing human ovarian cancer cell line HO8910PM and its mother cell line HO-8910. Method: The expression of 9 kinds of gene products in HO-8910PM and its mother cell line HO-8910 was detected by S-P immunohistochemical method. Result: Eight kinds oncogene products showed various degrees of positive expression in both HO-8910PM and HO-8910 cell lines except gene bax. The expression of P53, Cyclin D1, CD44v6 and EGFR in HO-8910PM was stronger than that in HO-8910. However, the expression of P16, nm23 in HO8910PM was weaker than that in HO-8910. There was no significant difference on the expression of C-erbB-2 and bcl-2 between the two cell lines. Conclusion: Stronger invasive and metastatic patential is found in HO-8910PM than that in HO-8910. Carcinogenesis is a result of multioncogene and multiple step process cooperation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Citron, Robert; Kropf, A.J.

    2008-01-01

    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.

  17. Yb-based heavy fermion compounds and field tuned quantum chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Mun, Eundeok [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    The motivation of this dissertation was to advance the study of Yb-based heavy fermion (HF) compounds especially ones related to quantum phase transitions. One of the topics of this work was the investigation of the interaction between the Kondo and crystalline electric field (CEF) energy scales in Yb-based HF systems by means of thermoelectric power (TEP) measurements. In these systems, the Kondo interaction and CEF excitations generally give rise to large anomalies such as maxima in ρ(T) and as minima in S(T). The TEP data were use to determine the evolution of Kondo and CEF energy scales upon varying transition metals for YbT2Zn20 (T = Fe, Ru, Os, Ir, Rh, and Co) compounds and applying magnetic fields for YbAgGe and YbPtBi. For YbT2Zn20 and YbPtBi, the Kondo and CEF energy scales could not be well separated in S(T), presumably because of small CEF level splittings. A similar effect was observed for the magnetic contribution to the resistivity. For YbAgGe, S(T) has been successfully applied to determine the Kondo and CEF energy scales due to the clear separation between the ground state and thermally excited CEF states. The Kondo temperature, TK, inferred from the local maximum in S(T), remains finite as magnetic field increases up to 140 kOe. In this dissertation we have examined the heavy quasi-particle behavior, found near the field tuned AFM quantum critical point (QCP), with YbAgGe and YbPtBi. Although the observed nFL behaviors in the vicinity of the QCP are different between YbAgGe and YbPtBi, the constructed H-T phase diagram including the two crossovers are similar. For both YbAgGe and YbPtBi, the details of the quantum criticality turn out to be complicated. We expect that YbPtBi will provide an additional example of field tuned quantum criticality, but clearly there are further experimental investigations left and more ideas needed to understand the basic physics of field-induced quantum

  18. The Cold Shock Domain of YB-1 Segregates RNA from DNA by Non-Bonded Interactions.

    Directory of Open Access Journals (Sweden)

    Vladislav Kljashtorny

    Full Text Available The human YB-1 protein plays multiple cellular roles, of which many are dictated by its binding to RNA and DNA through its Cold Shock Domain (CSD. Using molecular dynamics simulation approaches validated by experimental assays, the YB1 CSD was found to interact with nucleic acids in a sequence-dependent manner and with a higher affinity for RNA than DNA. The binding properties of the YB1 CSD were close to those observed for the related bacterial Cold Shock Proteins (CSP, albeit some differences in sequence specificity. The results provide insights in the molecular mechanisms whereby YB-1 interacts with nucleic acids.

  19. A MAGNUS EXPANSION FOR THE EQUATION Y′ = AY - YB

    Institute of Scientific and Technical Information of China (English)

    Arieh Iserles

    2001-01-01

    The subject matter of this paper is the representation of the solution of the linear differential equation Y′ = AY - YB, Y(O) = Yo, in the form Y(t) = eΩ(t)Yo and the representation of the function Ω as a generalisation of the classical Magnus expansion.An immediate application is a new recursive algorithm for the derivation of the BakerCampbell-Hausdorff formula and its symmetric generalisation.

  20. Diode-pumped Yb3+:KYF4 femtosecond laser.

    Science.gov (United States)

    Coluccelli, Nicola; Galzerano, Gianluca; Tonelli, Mauro; Laporta, Paolo; Svelto, Orazio

    2008-05-15

    Passive mode locking of a diode-pumped Yb(3+):KYF(4) laser is demonstrated using a semiconductor saturable absorber mirror. A high-stability, transform-limited pulse train with a repetition rate of 57 MHz is generated. Solitonlike pulses with maximum average output power of 250 mW, minimum pulse duration of 170 fs, and rms time jitter of 360 fs were obtained.

  1. Efficient lasing in Yb:(YLa)2O3 ceramics

    Science.gov (United States)

    Snetkov, I. L.; Mukhin, I. B.; Balabanov, S. S.; Permin, D. A.; Palashov, O. V.

    2015-02-01

    A high-optical-quality sample of Yb0.1Y1.7La0.2O3 ceramics is prepared using a recently developed technique of selfpropagating high-temperature synthesis of rare-earth-doped yttrium oxide nanopowder from acetate - nitrates of metals. Its optical and spectral characteristics are studied, and quasi-cw lasing at a wavelength of 1033 nm is achieved with a power of 7 W and a slope efficiency of 25%.

  2. Comparative toxicity of nanoparticulate/bulk Yb₂O₃ and YbCl₃ to cucumber (Cucumis sativus).

    Science.gov (United States)

    Zhang, Peng; Ma, Yuhui; Zhang, Zhiyong; He, Xiao; Guo, Zhi; Tai, Renzhong; Ding, Yayun; Zhao, Yuliang; Chai, Zhifang

    2012-02-01

    With the increasing utilization of nanomaterials, there is a growing concern for the potential environmental and health effects of them. To assess the environmental risks of nanomaterials, better knowledge about their fate and toxicity in plants are required. In this work, we compared the phytotoxicity of nanoparticulate Yb(2)O(3), bulk Yb(2)O(3), and YbCl(3)·6H(2)O to cucumber plants. The distribution and biotransformation of the three materials in plant roots were investigated in situ by TEM, EDS, as well as synchrotron radiation based methods: STXM and NEXAFS. The decrease of biomass was evident at the lowest concentration (0.32 mg/L) when exposed to nano-Yb(2)O(3), while at the highest concentration, the most severe inhibition was from YbCl(3). The inhibition was dependent on the actual amount of toxic Yb uptake by the cucumber plants. In the intercellular regions of the roots, Yb(2)O(3) particles and YbCl(3) were all transformed to YbPO(4). We speculate that the dissolution of Yb(2)O(3) particles induced by the organic acids exuded from roots played an important role in the phytotoxicity. Only under the nano-Yb(2)O(3) treatment, YbPO(4) deposits were found in the cytoplasm of root cells, so the phytotoxicity might also be attributed to the Yb internalized into the cells.

  3. Nanostructured Yb:GGG polycrystalline powders via gel combustion method

    Institute of Scientific and Technical Information of China (English)

    HUANG Dexin; ZHANG Xuejian; LIU Jinghe; ZHANG Dan

    2009-01-01

    Gadolinium gallium garnet (GGG) nanopowders doped with ytterbium ions (Yb:GGG) were synthesized with citric acid as a fuel via gel combustion method. The optimized conditions for preparing Yb3+:Gd3Ga5O12 nanopowders were discussed. The heat behavior, struc-ture and morphology of powders were analyzed with thermal analysis (TG-DTA), X-ray diffraction (XRD), infrared spectra (IR) and trans-mission electron microscope (TEM). TG-DTA analysis revealed that the weight loss of the precursor occured below 800 ℃ and its crystalli-zation temperature was 830.6 ℃. XRD and IR analysis showed that the precursor converted directly into pure GGG at a relatively lower tem-perature (900 ℃) without any other intermediate phase. The lattice constant was 1.2377 calculated by extrapolation method. TEM results in-dicated that the spherical powders showed good dispersity and had a relatively narrow size distribution with average particle size of approxi-mately 40-50 nm, which was favorable for good sinterability of Yb:GCG laser ceramic.

  4. Návrh automatického obchodního systému pro forex

    OpenAIRE

    Kolář, Jan

    2016-01-01

    Diplomová práce se zabývá navržením automatického obchodního systému určeného především pro intra-denní obchodování na měnových trzích. Cílem práce je vytvořit ucelený teoretický základ, v praktické části práce poznatky využít k vytvoření vhodného automatického obchodního systému. V práci je kladen důraz zejména na technickou a částečně psychologickou analýzu měnových trhů. Navržený systém bude vhodně optimalizován pro maximalizaci zisku a stability s aplikací na nejlikvidnějších měnových pár...

  5. Scissors Mode of 162Dy Studied from Resonance Neutron Capture

    Directory of Open Access Journals (Sweden)

    Baramsai B.

    2015-01-01

    Full Text Available Multi-step cascade γ-ray spectra from the neutron capture at isolated resonances of 161Dy nucleus were measured at the LANSCE/DANCE time-of-flight facility in Los Alamos National Laboratory. The objectives of this experiment were to confirm and possibly extend the spin assignment of s-wave neutron resonances and get new information on photon strength functions with emphasis on the role of the M1 scissors mode vibration. The preliminary results show that the scissors mode plays a significant role in all transitions between accessible states of the studied nucleus. The photon strength functions describing well our data are compared to results from 3He-induced reactions, (n,γ experiments on Gd isotopes, and (γ,γ’ reactions.

  6. Scissors Mode of 162Dy Studied from Resonance Neutron Capture

    Science.gov (United States)

    Baramsai, B.; Bečvář, F.; Bredeweg, T. A.; Haight, R. C.; Jandel, M.; Kroll, J.; Krtička, M.; Mitchell, G. E.; O'Donnell, J. M.; Rundberg, R. S.; Ullmann, J. L.; Valenta, S.; Wilhelmy, J. B.

    2015-05-01

    Multi-step cascade γ-ray spectra from the neutron capture at isolated resonances of 161Dy nucleus were measured at the LANSCE/DANCE time-of-flight facility in Los Alamos National Laboratory. The objectives of this experiment were to confirm and possibly extend the spin assignment of s-wave neutron resonances and get new information on photon strength functions with emphasis on the role of the M1 scissors mode vibration. The preliminary results show that the scissors mode plays a significant role in all transitions between accessible states of the studied nucleus. The photon strength functions describing well our data are compared to results from 3He-induced reactions, (n,γ) experiments on Gd isotopes, and (γ,γ') reactions.

  7. Short-wavelength emission analysis in Dy:ZBLAN glasses

    Science.gov (United States)

    Piramidowicz, R.; Klimczak, M.; Malinowski, M.

    2008-01-01

    In this work we examine short-wavelength (blue, yellow and red) emission properties of dysprosium activated fluorozirconate ZBLAN glass. On the basis of the measured broad band absorption spectrum the intensity parameters Ωi were calculated using Judd-Ofelt formalism, yielding values of transition probabilities and radiative lifetimes. The basic spectroscopic characterization of Dy:ZBLAN was also performed, including visible emission and fluorescence decay measurements under pulsed, direct and two-photon up-conversion excitation. The theoretically predicted properties, specifically concerning the fluorescence lifetimes, were found to be in a rough agreement with experimentally determined values which was improved by isolation of magnetic dipole and impurity contributions to absorption spectrum.

  8. Forensic discrimination of dyed hair color: II. Multivariate statistical analysis.

    Science.gov (United States)

    Barrett, Julie A; Siegel, Jay A; Goodpaster, John V

    2011-01-01

    This research is intended to assess the ability of UV-visible microspectrophotometry to successfully discriminate the color of dyed hair. Fifty-five red hair dyes were analyzed and evaluated using multivariate statistical techniques including agglomerative hierarchical clustering (AHC), principal component analysis (PCA), and discriminant analysis (DA). The spectra were grouped into three classes, which were visually consistent with different shades of red. A two-dimensional PCA observations plot was constructed, describing 78.6% of the overall variance. The wavelength regions associated with the absorbance of hair and dye were highly correlated. Principal components were selected to represent 95% of the overall variance for analysis with DA. A classification accuracy of 89% was observed for the comprehensive dye set, while external validation using 20 of the dyes resulted in a prediction accuracy of 75%. Significant color loss from successive washing of hair samples was estimated to occur within 3 weeks of dye application.

  9. Reddish-orange, neutral and warm white emissions in Eu3+, Dy3+ and Dy3+/Eu3+ doped CdO-GeO2-TeO2 glasses

    Science.gov (United States)

    Rodríguez-Carvajal, David A.; Meza-Rocha, A. N.; Caldiño, U.; Lozada-Morales, R.; Álvarez, E.; Zayas, Ma. E.

    2016-11-01

    Eu3+, Dy3+ and Dy3+/Eu3+ doped CdO-GeO2-TeO2 glasses were prepared using the melt-quenching process and analyzed by X-diffraction, Raman spectroscopy, excitation and emission spectra, and emission decay time profiles. The lack of X ray diffraction peaks revealed that all samples are amorphous. Vibrational modes associated with Tesbnd Osbnd Te and Gesbnd Osbnd Ge related bonds and molecular oxygen were detected by Raman spectroscopy. The luminescence characteristics were studied upon excitations that correspond with the emission of InGaN (370-420 nm) based LEDs. The Eu3+ singly doped glass displayed reddish-orange global emission, with x = 0.601 and y = 0.349 CIE1931 chromaticity coordinates, upon 393 nm excitation. Neutral emission with x = 0.373 and y = 0.412 CIE1931 chromaticity coordinates and correlated color temperature (CCT) of 4400 K, was achieved in the Dy3+ singly doped glass excited at 388 nm. The Dy3+/Eu3+ co-doped glass exhibited warm, neutral and soft warm white emissions with CCT values of 3435, 4153 and 2740 K, under excitations at 382, 388 and 393 nm, respectively, depending mainly on the Dy3+ and Eu3+ relative excitation. The Dy3+ excitation bands observed in the Dy3+/Eu3+ glass by monitoring the 611 nm Eu3+ emission, suggest that Dy3+ → Eu3+ energy transfer takes place, despite the fact that the Dy3+ emission decays in the Dy3+ and Dy3+/Eu3+ doped glass, remain without changes. The shortening of Eu3+ decay in presence of Dy3+ was attributed to an Eu3+ → Dy3+ non-radiative energy transfer process, which according with the Inokuti-Hirayama model might be dominated through an electric quadrupole-quadrupole interaction, with efficiency and probability of 5.5% and 51.6 s-1, respectively.

  10. Updated level scheme of 172Yb from 171Yb(nth, γ) reaction studied via gamma-gamma coincidence spectrometer

    Science.gov (United States)

    Nguyen, Ngoc Anh; Nguyen, Xuan Hai; Pham, Dinh Khang; Nguyen, Quang Hung; Ho, Huu Thang

    2017-08-01

    This paper provides the updated information on the level scheme of 172Yb nucleus studied via 171Yb(nth, γ) reaction using the gamma-gamma coincidence spectrometer at Dalat Nuclear Research Institute (Viet Nam). The latter is used because of its advantages in achieving the low Compton background as well as in identifying the correlated gamma transitions. We have detected in total the energies and intensities of 128 two-step gamma cascades corresponding to 79 primary transitions. By comparing the measured data with those extracted from the ENSDF library, 61 primary gamma transitions and corresponding energy levels together with 20 secondary gamma transitions are found to be the same as the ENSDF data. Beside that, 18 additional primary gamma transitions and corresponding energy levels plus 108 secondary ones are not found to currently exist in this library and they are therefore considered as the new data.

  11. Spectral properties of hydrothermally-grown Nd:LuAG, Yb:LuAG, and Yb:Lu{sub 2}O{sub 3} laser materials

    Energy Technology Data Exchange (ETDEWEB)

    Brown, David C., E-mail: DBrown@snakecreeklasers.com [Snake Creek Lasers LLC, Friendsville, PA 18818 (United States); McMillen, Colin D.; Moore, Cheryl; Kolis, Joseph W. [Department of Chemistry and Center for Optical Materials Science and Engineering Technologies, Clemson University, Clemson, SC 29634-0973 (United States); Envid, Victoria [Snake Creek Lasers LLC, Friendsville, PA 18818 (United States)

    2014-04-15

    We have investigated the hydrothermal growth of, and spectrally characterized, the lutetium based laser materials Nd:LuAG, Yb:LuAG, and Yb:Lu{sub 2}O{sub 3}. Absorption cross-section data are presented for Nd:LuAG at 83, 175, and 295 K. Absorption cross-section data was also obtained for Yb:LuAG at 83, 175, and 295 K; the 295 K data was used to generate emission cross-sections using the method of reciprocity. For Yb:Lu{sub 2}O{sub 3}, we present absorption cross-sections at 295 K as well as emission cross-sections derived using reciprocity. -- Highlights: • We present spectral properties for hydrothermally-grown laser crystals. • Absorption cross-section data are presented for Nd:LuAG and Yb:LuAG at 83, 175, and 295 K. • Emission cross-sections are presented for Yb:LuAG at 295 K derived by reciprocity. • We present absorption cross-sections at 295 K as well as emission cross-sections derived using reciprocity for the laser material Yb:Lu{sub 2}O{sub 3}.

  12. Single crystal growth of the heavy fermion compounds YbRh{sub 2}Si{sub 2} and YbNi{sub 4}P{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Butzke, Constantin; Kliemt, Kristin; Krellner, Cornelius [Physikalisches Institut, Goethe Universitaet Frankfurt, 60438 Frankfurt am Main (Germany)

    2015-07-01

    Heavy fermion systems are model systems to unravel the exciting physics around quantum-phase transitions. Studying these emergent phenomena necessitates the preparation of large and high-quality single crystals. We report on the optimization of the single crystal growth for two Yb-based quantum critical materials, YbRh{sub 2}Si{sub 2} and YbNi{sub 4}P{sub 2}. The prototype heavy-fermion system YbRh{sub 2}Si{sub 2} is situated extremely close to an unconventional antiferromagnetic (AF) quantum critical point (QCP). The AF ordering (T{sub N} = 70 mK) can be further lowered by chemically induced negative pressure using Ir-substitution. The QCP is reached for an Ir-substitution of x ∼ 0.1 in Yb(Rh{sub 1-x}Ir{sub x}){sub 2}Si{sub 2}. Here, we report on the optimization of the crystal growth of the substitution series as well as of the unsubstituted compound. We also report on our attempts to determine the melting point of YbRh{sub 2}Si{sub 2} and present a phase analysis of the molten compound. In the heavy fermion metal, YbNi{sub 4}P{sub 2}, a ferromagnetic (FM) transition at T{sub C} = 0.17 K was observed recently and a FM QCP is reached at x ∼ 0.1 in YbNi{sub 4}(P{sub 1-x}As{sub x}){sub 2}. We report on the crystal growth of YbNi{sub 4}P{sub 2} by Czochralski method out of a Ni-P flux from a levitated melt. The obtained crystals were characterized by Laue X-ray scattering, X-ray powder diffraction, EDX microprobe analysis and resistivity measurements.

  13. Investigations of the effect of nonmagnetic Ca substitution for magnetic Dy on spin-freezing in Dy₂Ti₂O₇.

    Science.gov (United States)

    Anand, V K; Tennant, D A; Lake, B

    2015-11-01

    Physical properties of partially Ca substituted hole-doped Dy2Ti2O7 have been investigated by ac magnetic susceptibility χ(ac)(T), dc magnetic susceptibility χ(T), isothermal magnetization M(H) and heat capacity C(p)(T) measurements on Dy1.8Ca0.2Ti2O7. The spin-ice system Dy2Ti2O7 exhibits a spin-glass type freezing behavior near 16 K. Our frequency dependent χ(ac)(T) data of Dy1.8Ca0.2Ti2O7 show that the spin-freezing behavior is significantly influenced by Ca substitution. The effect of partial nonmagnetic Ca(2+) substitution for magnetic Dy(3+) is similar to the previous study on nonmagnetic isovalent Y(3+) substituted Dy(2-x)Y(x) Ti2O7 (for low levels of dilution), however the suppression of spin-freezing behavior is substantially stronger for Ca than Y. The Cole-Cole plot analysis reveals semicircular character and a single relaxation mode in Dy1.8Ca0.2Ti2O7 as for Dy2Ti2O7. No noticeable change in the insulating behavior of Dy2Ti2O7 results from the holes produced by 10% Ca(2+) substitution for Dy(3+) ions.

  14. DYEING OF SILK/WOOL USING CRUDE PIGMENT EXTRACT FROM AN ISOLATE KOCURIA FLAVA SP. HO-9041

    Directory of Open Access Journals (Sweden)

    Vaishali M. Kulkarni

    2014-12-01

    Full Text Available The prolonged use of natural colours has not only had an adverse effect on environment but also human health. In view of these concerns, natural colours/pigments are now becoming alternatives to synthetic ones. The present study involved isolation, identification, and characterization of the natural pigment producing bacteria and its applicability in textile field. Various microbes screened from the garden soil of our institute (ICT Mumbai resulted in isolation of a yellow-pigment-producing bacterium. The 16s-rRNA results disclosed that these bacteria had 99% similarity to Kocuria flava sp. HO-9041. The dyeing of fabric (silk and wool with the extracted pigment showed a good dye uptake, and the colour strength given by K/S (ratio of absorption/scattering increased satisfactorily upon dying with bacterial pigment. These tests showed the ability of the pigment to be used as colorant for fabrics, enhanced more so by the dying in absence of a mordant (substance used for attaching dye to fabric. Apart from its applicability in textiles, the pigment showed antibacterial activity also. This may give rise to potential applications of such dyed fabrics in apparels, children-ware, and medical textiles, where hygienic conditions are required.

  15. Rietveld Refinement of New Ternary Compound Al14Dy5Si

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new ternary compound Al14Dy5Si was discovered and studied by means of X-ray powder diffraction technique. The ternary compound Al14Dy5Si has a hexagonal BaPb3-type structure, space group R3m(No.166), the lattice parameters a=0.61482(1) nm, c=2.09780(2) nm. The crystal structure of the compound Al14Dy5Si was successfully refined by using Rietveld method from X-ray diffraction data. The R-factors of Rietveld refinement are Rp=0.091 and Rwp=0.120, respectively. The thermal dependence of the magnetization (M-T curves) for the compound was measured by a vibrating sample magnetometer. The experimentally determined magnetic effective paramagnetic moment is μeff=23.22 μB per formula unit (10.36 μB per Dy atom).

  16. Diffusion Raman et luminescence dans des aerogels de silice purs ou dopes Dy

    Science.gov (United States)

    Guerri, F.; Fabre, F.; Zwick, A.; Bournett, D.

    1994-02-01

    Light scattering studies of pure and Dy doped aerogels are presented. Careful examination of Stokes and anti-Stokes spectra allow the discrimination between Raman and luminescence processes. It is shown that in pure aerogels, scattered intensity is due to Raman processes only, and the density of vibrational states does not exhibit any singularity. The fractal properties of the structure imply modifications not only in the spectral distribution of the low frequency modes (usually labelled phonons and fractons) but alsoin the high frequency one, at least up to 600 cm-1. In Dy-doped dense silica, coupling between electronic and vibronic excitations is evidenced by the presence of anti-Stokes luminescence. In Dy-doped aerogels, the enlarged Dy3+ electronic levels, strongly coupled with vibrational states give rise to emission processes traducing the response of the sample as a whole, rather than resonant Raman scattering or luminescence processes.

  17. Studies on dyed coconut (Cocos nucifera) pollens for removal of Cu (II)

    African Journals Online (AJOL)

    GREGO

    ducts are available at little or no cost and are naturally occurring. Also, they ... dyed coconut pollen by dyeing with reactive dyes, ... The dye utilized for the study was prepared by the method described .... Colour Removal from Dye Wastewaters.

  18. Oxide evolution in NdDy-Fe-B magnet during aging process

    Institute of Scientific and Technical Information of China (English)

    WANG Jingdai; FENG Haibo; LI Anhua; LI Yanfeng; ZHU Minggang; LI Wei

    2012-01-01

    Sintered NdDy-Fe-B magnets were made from strip cast flakes by powder metallurgy method.For the magnet with 6 wt.% Dy substituted Nd,a remarkable coercivity increase of 70% was obtained after aging at 900 ℃ for 2 h and a high coercivity of 23.5 kOe was achieved after aging at 520 ℃ for 2 h.The average diameter of the oxide particles decreased during the following 900 ℃ aging treatment.Dy and O diffusion from oxide particles to Nd-rich phase during the aging process was observed.The oxide evolution and Dy element diffusion were helpful to the coercivity enhancement.

  19. Dyeing of white and indigo dyed cotton fabrics with Mimosa tenuiflora extract

    Directory of Open Access Journals (Sweden)

    Gökhan Erkan

    2014-04-01

    Full Text Available Mimosa tenuiflora extract has been used in food industry as an additive and in textile and leather industry as a colorant. Two types of fabrics, ready to be dyed white and indigo dyed fabrics, were dyed with M. tenuiflora extract. The fabrics were mordanted after dyeing with six different metal salts. Colorimetric evaluations of fabrics were carried out by spectrophotometer. Colour fastness to washing, rubbing and light were performed. Colour strength of fabrics was calculated from Kubelka–Munk formula. Highest vividness (C∗ values were obtained by Ni mordant. Moderate fastness values were observed. However poor wet rubbing fastness values were observed in the case of indigo dyed fabrics due to lack of good wet rubbing fastness of indigo itself.

  20. Dielectric Properties of Dy2O3 -Doped ( Ba, Sr) TiO3 Ceramics

    Institute of Scientific and Technical Information of China (English)

    Huang Xinyou; Gao Chunhua; Chen Xiangchong; Zheng Xialian; Huang Guojun; Liu Huiping

    2004-01-01

    The effects of Dy2O3 doping on the dielectric properties of (Ba, Sr)TiO3 series capacitor ceramics prepared using solid-state reaction method were studied. With the increasing of Dy2O3 additive , the dielectric constant (ε) of materials increases to a maximum when w(Dy2O3 ) is about 0.5% ,while the dielectric loss(tanδ) decreases. The BST ceramics with highε ( = 5245 ), low tanδ ( = 0. 0026 ) and high DC breakdown voltage ( = 5.5 mV ·m-1 ) were obtained. The influencing mechanism of Dy2O3 on the dielectric properties of (Ba, Sr)TiO3 ceramics was studied, thus providing the basis for preparation of capacitor ceramics.