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Sample records for er yt dy

  1. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, Jr., Karl A.; Takeya, Hiroyuki

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy.sub.1-x Er.sub.x)Al.sub.2 for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant.

  2. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, K.A. Jr.; Takeya, Hiroyuki

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant. 29 figs.

  3. Magnetic structure of dysprosium in epitaxial Dy films and in Dy/Er superlattices

    SciTech Connect

    Dumesnil, K.; Dufour, C.; Mangin, P.; Marchal, G.; Hennion, M.

    1996-09-01

    We present a magnetization and neutron-diffraction study of the basal plane magnetic structure of Dy epitaxial films and Dy/Er superlattices. The thermal evolution of the magnetic phases, the stability of the helical phase under a magnetic field, the thermal variation of the dysprosium in-plane and {ital c} parameters, and of the dysprosium turn angle are successively shown. In Dy/Er superlattices, the dysprosium helix propagates coherently through paramagnetic erbium; at low temperature, individual dysprosium layers undergo a ferromagnetic transition and are coupled antiferromagnetically to each other for erbium layers thicknesses larger than 20 A. In dysprosium films, as expected from the epitaxy effect, the Curie temperature of dysprosium is reduced if dysprosium is grown on yttrium and increased if it is grown on erbium, whereas it is unexpectedly close to the bulk value in Dy/Er superlattices. This amazing value of the Curie temperature in superlattices is correlated to two main experimentally observed effects: (i) the magnetoelastic driving force is reduced compared to bulk dysprosium because of the clamped {gamma} distortion; (ii) the difference between the exchange energies in the helical and the ferromagnetic phases is increased compared to the bulk value. {copyright} {ital 1996 The American Physical Society.}

  4. Photoluminescence properties of thermographic phosphors YAG:Dy and YAG:Dy, Er doped with boron and nitrogen

    NASA Astrophysics Data System (ADS)

    Chepyga, Liudmyla M.; Jovicic, Gordana; Vetter, Andreas; Osvet, Andres; Brabec, Christoph J.; Batentschuk, Miroslaw

    2016-08-01

    This paper investigates Dy3+-doped and Dy3+, Er3+-co-doped yttrium aluminum garnets (YAG) with the admixture of boron nitride with the aim of using them as efficient thermographic phosphors at high temperatures. The phosphors were synthesized using a conventional high-temperature solid-state method. The influence of two fluxes, B2O3 and LiF/NH4F, and the effect of activator and coactivator concentrations were investigated. Additionally, the effect of B3+ and N3- substituting for Al3+ and O2- ions, respectively, in the YAG:Dy3+ co-doped with Er3+ was studied for the first time. The changes in the host lattice led to a much stronger photoluminescence compared with the samples without B3+ and N3- substitution. The admixture of BN also improves the thermal sensitivity of the YAG:Dy and YAG:Dy, Er thermographic phosphors.

  5. Emergence of Chaotic Scattering in Ultracold Er and Dy

    NASA Astrophysics Data System (ADS)

    Maier, T.; Kadau, H.; Schmitt, M.; Wenzel, M.; Ferrier-Barbut, I.; Pfau, T.; Frisch, A.; Baier, S.; Aikawa, K.; Chomaz, L.; Mark, M. J.; Ferlaino, F.; Makrides, C.; Tiesinga, E.; Petrov, A.; Kotochigova, S.

    2015-10-01

    We show that for ultracold magnetic lanthanide atoms chaotic scattering emerges due to a combination of anisotropic interaction potentials and Zeeman coupling under an external magnetic field. This scattering is studied in a collaborative experimental and theoretical effort for both dysprosium and erbium. We present extensive atom-loss measurements of their dense magnetic Feshbach-resonance spectra, analyze their statistical properties, and compare to predictions from a random-matrix-theory-inspired model. Furthermore, theoretical coupled-channels simulations of the anisotropic molecular Hamiltonian at zero magnetic field show that weakly bound, near threshold diatomic levels form overlapping, uncoupled chaotic series that when combined are randomly distributed. The Zeeman interaction shifts and couples these levels, leading to a Feshbach spectrum of zero-energy bound states with nearest-neighbor spacings that changes from randomly to chaotically distributed for increasing magnetic field. Finally, we show that the extreme temperature sensitivity of a small, but sizable fraction of the resonances in the Dy and Er atom-loss spectra is due to resonant nonzero partial-wave collisions. Our threshold analysis for these resonances indicates a large collision-energy dependence of the three-body recombination rate.

  6. Calculations of signature for Dy, Er, Yb nuclei

    SciTech Connect

    Mueller, W.F.; Jensen, H.J.; Reviot, W.

    1993-10-01

    Energy signature splitting {Delta}e` of rotational bands depends sensitively on deformation, pair correlations, and Fermi level in the particular nucleus. Calculating {Delta}e` is therefore very useful in understanding the experimentally observed properties of such bands. In principal, one can extract {Delta}e` from Total Routhian Surface (TRS) calculations as well as from the Cranked Shell Model (CSM). However, the codes available are not based on a fully self-consistent treatment of all critical parameters, deformation, pairing, and Fermi level. The TRS calculations, while modeling the deformation in a {open_quote}realistic{close_quotes} manner as a function of rotational frequency and changes in the quasiparticle configuration, have deficiencies particularly in the treatment of pairing. The CSM codes, on the other hand, estimate pairing and the location of the Fermi level more precisely than the TRS codes, but work under the assumption of a constant deformation. We have developed a method to calculate {Delta}e` that utilizes the most advanced features of both types of codes. This ensures that the best parameter values are used as input for calculating the routhians. As a test, we have used a series of odd-A Dy, Er, and Yb nuclei around A = 160 and compared the results for the vi{sub 13/2} shell with experimental data on {Delta}e`. Details of our method will be discussed and the comparison will be presented.

  7. Structural and photoluminescence properties of Ce, Dy, Er-doped ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Jayachandraiah, C.; Kumar, K. Siva; Krishnaiah, G.

    2015-06-01

    Undoped ZnO and rare earth elements (Ce, Dy and Er with 2 at. %) doped nanoparticles were synthesized by wet chemical co-precipitation method at 90°C with Polyvinylpyrrolidone (PVP) as capping agent. The structural, morphological, compositional and photoluminescence studies were performed with X-ray diffraction (XRD), Transmission electron microscopy (TEM), Energy dispersive spectroscopy (EDS), FTIR spectroscopy and Photoluminescence (PL) respectively. XRD results revealed hexagonal wurtzite structure with average particle size around 18 nm - 14 nm and are compatible with TEM results. EDS confirm the incorporation of Ce, Dy and Er elements into the host ZnO matrix and is validated by FTIR analysis. PL studies showed a broad intensive emission peak at 558 nm in all the samples. The intensity for Er- doped ZnO found maximum with additional Er shoulder peaks at 516nm and 538 nm. No Ce, Dy emission centers were found in spectra.

  8. Structural and photoluminescence properties of Ce, Dy, Er-doped ZnO nanoparticles

    SciTech Connect

    Jayachandraiah, C.; Kumar, K. Siva; Krishnaiah, G.

    2015-06-24

    Undoped ZnO and rare earth elements (Ce, Dy and Er with 2 at. %) doped nanoparticles were synthesized by wet chemical co-precipitation method at 90°C with Polyvinylpyrrolidone (PVP) as capping agent. The structural, morphological, compositional and photoluminescence studies were performed with X-ray diffraction (XRD), Transmission electron microscopy (TEM), Energy dispersive spectroscopy (EDS), FTIR spectroscopy and Photoluminescence (PL) respectively. XRD results revealed hexagonal wurtzite structure with average particle size around 18 nm - 14 nm and are compatible with TEM results. EDS confirm the incorporation of Ce, Dy and Er elements into the host ZnO matrix and is validated by FTIR analysis. PL studies showed a broad intensive emission peak at 558 nm in all the samples. The intensity for Er- doped ZnO found maximum with additional Er shoulder peaks at 516nm and 538 nm. No Ce, Dy emission centers were found in spectra.

  9. Beta-delayed proton activities: /sup 147/Dy and /sup 149/Er

    SciTech Connect

    Toth, K.S.; Moltz, D.M.; Schloemer, E.C.; Cable, M.D.; Avignone, F.T. III; Ellis-Akovali, Y.A.

    1984-01-01

    The present paper discusses mainly the ..beta..-delayed proton spectra of /sup 147/Dy and of the hitherto unknown isotope, /sup 149/Er. However, following the submittal of the abstract for this conference we have now observed delayed protons following the decay of /sup 145/Dy. Additionally, we have identified a 0.5-s delayed-proton emitter and tentatively assign it to the new isotope, /sup 151/Yb.

  10. Magnetocaloric effect of the ternary Dy, Ho and Er platinum gallides

    NASA Astrophysics Data System (ADS)

    França, E. L. T.; dos Santos, A. O.; Coelho, A. A.; da Silva, L. M.

    2016-03-01

    Magnetic and magnetocaloric properties of equiatomic ternary gallides RPtGa (R=Dy, Ho and Er) compounds have been reported. All these compounds are iso-structural and order antiferromagnetically below 20 K. External applied magnetic field induces metamagnetic transition from antiferromagnetic to ferromagnetic state. Adiabatic entropy change (-ΔSM) shows negative contribution for magnetic field changes up to 10 kOe (for R=Ho and Er) and 30 kOe (for R=Dy) due to disordering of antiparallel spins with the external applied field. As the field change increases, only a positive asymmetric peak is observed. A broad -ΔSM peak is observed for HoPtGa, evidencing characteristics of a table-like behavior. HoPtGa and ErPtGa present the largest magnetocaloric effect (EMC) compared with DyPtGa, indicating that the nature of metamagnetic transition affects the magnetocaloric properties. The maximum value of adiabatic temperature change (∆ Tadmax) obtained for R=Dy, Ho and Er was respectively 4.1 K, 4.9 K and 6.7 K for ΔH=50 kOe. These values are comparable with the respective ∆ Tadmax reported for other RTX compounds in the same range of temperature and suggest that RPtGa compounds are attractive candidates for magnetic refrigeration in low temperature range (<20 K) with the advantage of not presenting hysteresis loss.

  11. Exchange spring switching in Er-doped DyFe2/YFe2 magnetic thin films

    NASA Astrophysics Data System (ADS)

    Stenning, G. B. G.; Bowden, G. J.; de Groot, P. A. J.; van der Laan, G.; Figueroa, A. I.; Bencok, P.; Steadman, P.; Hesjedal, T.

    2015-09-01

    Reversible magnetic exchange springs can be formed in multilayer films, grown by molecular beam epitaxy. Here we demonstrate that small amounts of anisotropic ErFe2, placed in the middle of the YFe2 magnetic exchange springs, can bring about substantial changes. Results are presented for an Er-doped (110)-oriented multilayer film, at 100 K in fields of up to ±14 T. Using both Er and Dy-specific soft x-ray magnetic circular dichroism and micromagnetic modeling, it is demonstrated that Er doping gives rise to (i) noncollinear exchange spring states in zero field, (ii) magnetic exchange spring collapse, (iii) a marked increase in the number of different exchange spring states available to the system, and (iv) strikingly different Er and Dy magnetization loops. Full and partial loops are presented for both the in-plane hard and easy axes. The magnetization loops for Dy sublattice show that at least ten different exchange spring states are accessed during magnetic reversal. Magnetic switching scenarios, involving mixtures of Néel-like and Bloch-like domain walls, are presented and discussed.

  12. Competition of superconductivity and antiferromagnetism in RNi2B2C (R = Tm, Dy, Ho, Er)

    NASA Astrophysics Data System (ADS)

    Sahoo, B. K.; Panda, B. N.

    2015-06-01

    The co-existence of superconductivity (SC) and antiferromagnetism (AFM) in RNi2B2C (R = Tm, Dy, Ho, Er) is reported in this paper. A mean field Hamiltonian model is taken for the system. The order parameters corresponding to SC and AFM are determined and their variation with temperature are studied for these borocarbide superconductors. The interplay of SC and AFM shows BCS type of two gaps in the quasi-particle density of states. Our theoretical study is an attempt to reveal how far the s-wave pairing taken in our model could explain the coexistence properties of SC and AFM in RNi2B2C.

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

    PubMed

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

    2010-12-01

    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. PMID:21406760

  14. Luminescent LuVO4:Ln3+ (Ln = Eu, Sm, Dy, Er) hollow porous spheres for encapsulation of biomolecules

    NASA Astrophysics Data System (ADS)

    Li, Dan; Liu, Chunlei; Jiang, Lianzhou

    2015-10-01

    In this study, LuVO4:Ln3+ (Ln = Eu, Sm, Dy, Er) hollow porous spheres, synthesized via self-sacrificing templated route, are developed for enzyme immobilization and protein adsorption. The four LuVO4 hollow spheres with diameter of 180 nm, 280 nm, 370 nm and 480 nm were obtained. The size of LuVO4 hollow sphere is dependent on Lu(OH)CO3 template. Upon excitation by UV light, hollow LuVO4:Ln3+ (Ln = Eu, Sm, Dy, Er) spheres exhibit red (Eu3+), orange (Sm3+), yellow-green (Dy3+), and green (Er3+) emissions. The good biocompatibility of sample is validated by MTT assay. Due to structure feature and size of obtained sample, the rapid encapsulation of biomolecules within samples has been achieved. Furthermore, the hollow spheres show different biomolecules adsorption capacities at different buffer solution pH values. The release behaviors of two kinds of biomolecules (lysozyme and bovine serum albumin) are also investigated. LuVO4 hollow spheres are suitable carriers for biomolecules. The emission intensity of Eu3+ in the LuVO4:Eu3+ varies with the released amount of LYZ. This enables the monitoring of release process by the change in the luminescence intensity.

  15. Rare Earth Dopant (Nd, Gd, Dy, and Er) Hybridization in Lithium Tetraborate

    NASA Astrophysics Data System (ADS)

    Kelly, Tony; Petrosky, James; McClory, John; Adamiv, Volodymyr; Burak, Yaroslav; Padlyak, Bohdan; Teslyuk, Ihor; Lu, Ning; Wang, Lu; Mei, Wai-Ning; Dowben, Peter

    2014-05-01

    The four dopants (Nd, Gd, Dy, and Er) substitutionally occupy the Li+ sites in lithium tetraborate (Li2B4O7: RE) glasses as determined by analysis of the extended X-ray absorption fine structure. The dopants are coordinated by 6-8 oxygen at a distance of 2.3 to 2.5 Å, depending on the rare earth. The inverse relationship between the RE¬ O coordination distance and rare earth (RE) atomic number is consistent with the expected lanthanide atomic radial contraction with increased atomic number. Through analysis of the X-ray absorption near edge structure, the rare earth dopants adopt the RE3+ valence state. There are indications of strong rare earth 5d hybridization with the trigonal and tetrahedral formations of BO3 and BO4 based on the determination of the rare earth substitutional Li+ site occupancy from the X-ray absorption near edge structure data. The local oxygen disorder around the RE3+ luminescence centers evident in the structural determination of the various glasses, and the hybridization of the RE3+ dopants with the host may contribute to the asymmetry evident in the luminescence emission spectral lines. The luminescence emission spectra are indeed characteristic of the expected f-to-f transitions; however, there is an observed asymmetry in some emission lines.

  16. High-Pressure Magnetic Susceptibility Experiments on the Heavy Lanthanides Gd, Tb, Dy, Ho, Er, and Tm

    SciTech Connect

    Jackson, D D; Malba, V; Weir, S T; Baker, P A; Vohra, Y K

    2004-11-19

    The high pressure magnetic properties of the heavy lanthanide elements Gd, Tb, Dy, Ho, Er, and Tm have been investigated using ac magnetic susceptibility with a diamond anvil cell. It is found that the magnetic transition temperatures monotonically decrease with increasing pressure. In addition, the amplitudes of the magnetic transition signals decrease with increasing pressure, with the signals all eventually disappearing at pressures by 20 GPa. In contrast to previous studies, we see no evidence of any pressure-induced transitions from one magnetically ordered phase to another in Gd, Tb, Dy, or Ho. The transition temperatures, T{sub crit} are all found to drop at a rate proportional to their de Gennes factor, and the values of T{sub crit}/T{sub crit}(P = 0) vs P/P{sub crit}, where P{sub crit} is the pressure where the magnetic transition disappears, all sit on a single phase diagram.

  17. Incoherent scattering of 137Cs gamma rays in the rare earth elements Nd, Sm, Gd, Dy, Er and Yb

    NASA Astrophysics Data System (ADS)

    Krishnaveni, S.; Gowda, Shivalinge; Yashoda, T.; Umesh, T. K.; Gowda, Ramakrishna

    2005-09-01

    The differential incoherent scattering cross sections for 661.6 keV photons have been measured with an HPGe detector in the momentum range 4⩽x⩽46 Å-1 for the rare earth elements Nd, Sm, Gd, Dy, Er and Yb. The incoherent scattering functions were evaluated from the measured cross sections and compared with the NRHF values of Hubbel et al. [1975, J. Phys. Chem. Ref. Data 4, 471], the recent DHFR values of Kahane [1998, At. Data Nucl. Data Tables 68, 323] and other measured values. The present experimental values are systematically lower than the theoretical predictions, but show a good agreement within the experimental errors except for the momentum transfers of 30.59, 34.29 and 37.72 Å -1 for Nd, 43.69 Å -1 for Gd and 22.54 and 26.66 Å -1 for Dy, which show deviations at the two sigma level.

  18. Synthesis and photoluminescence properties of Ln3+ (Ln3+=Tb3+, Dy3+, Sm3+, Er3+)-doped Ca2Nb2O7 phosphors

    NASA Astrophysics Data System (ADS)

    Xian, Jieqiang; Yi, Shuangping; Deng, Yaomin; Zhang, Lu; Hu, Xiaoxue; Wang, Yinhai

    2016-02-01

    A series of Ln3+ (Ln3+=Tb3+/Dy3+/Sm3+/Er3+) ions doped Ca2Nb2O7 phosphors have been synthesized by high-temperature solid-state reaction. The Ln3+-doped samples are well indexed to the pure Ca2Nb2O7 phase which revealed for the X-ray diffraction (XRD) result. Under the ultraviolet light, the prepared Ca2-xNb2O7:xLn3+ (Ln3+=Tb3+/Dy3+/Sm3+/Er3+) phosphors show the characteristic cyan (Tb3+), green-white (Sm3+), yellowish (Dy3+) and green (Er3+) emissions. The energy transfer mechanisms in Ca2Nb2O7: Tb3+/Dy3+/Sm3+/Er3+ phosphors have been investigated and it deduced to be a resonant type via an electric dipole-dipole interaction. In addition, their critical distances have been calculated by concentration quenching methods. The luminescence properties of Ca2Nb2O7:Tb3+/Dy3+/Sm3+/Er3+ phosphors indicated that the Ca2Nb2O7 is a suitable host for rare earth doped laser crystal and optical materials.

  19. Magnetic properties of Er1-xDyxAl2 (0 ≤ x ≤ 1) compounds in low applied fields

    SciTech Connect

    Nirmala, R; Paudyal, Durga; Pecharsky, V K; Gschneidner, Jr., K.A.

    2010-04-19

    Low field magnetic properties of the Laves phase RAl{sub 2} compounds (where R is a mixture of Er and Dy, i.e., Er{sub 1-x}Dy{sub x} and x = 0, 0.1, 0.14, 0.18, 0.25, 0.33, 0.5, and 1) have been studied. These compounds order ferromagnetically, and the middle members show both metastability in a narrow temperature window within the ferromagnetically ordered state and signatures of first order transitions in low applied fields. Results of first principles electronic structure calculations on Er{sub 0.75}Dy{sub 0.25}Al{sub 2} indicate a significant difference in the spin polarization in the 5d states of Er{sup 3+} and Dy{sup 3+} moments. In addition, anisotropic exchange and crystalline electric field effects arise from the random distribution of rare earth ions in the lattice. These and quadrupolar effects triggered by aspherical charge distributions of Er{sup 3+} and Dy{sup 3+} ions may compete and lead to the low temperature anomalies observed in low field magnetization data.

  20. Thermodynamics of the lanthanide trifluorides. V. The heat capacities of dysprosium trifluoride, DyF3, and erbium trifluoride, ErF3, from 5 to 350 K

    NASA Astrophysics Data System (ADS)

    Flotow, Howard E.; O'Hare, P. A. G.

    1984-01-01

    The heat capacities of pure, well-characterized samples of DyF3 and ErF3 were measured by adiabatic calorimetry from 5 to 350 K. The heat capacities C○p, the entropies S°, the enthalpy increments H°(T)-H°(0), and the Planck functions -[G°(T)-H°(0)]/T are presented in tabular form at selected temperatures to 350 K. The values of the last three functions were adjusted for the removal of degeneracies associated with the magnetic ordering of DyF3 and ErF3 below 5 K. Also presented are recommended thermochemical functions at 298.15 K and tables of recommended high-temperature thermodynamic functions from 400 K to the melting temperatures. The excess heat capacities due to the internal electronic energy levels of Dy+3 in DyF3 and of Er+3 in ErF3 were calculated from calorimetric results. In the case of DyF3, the eight Kramer's doublets derived from spectroscopic measurements were used to calculate an excess heat capacity which is in good agreement with the calorimetric data.

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

    PubMed Central

    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. PMID:25364246

  2. Effect of rare-earth (Er and Gd) substitution on the magnetic and multiferroic properties of DyFe0.5Cr0.5O3.

    PubMed

    Sharma, Mohit K; Basu, Tathamay; Mukherjee, K; Sampathkumaran, E V

    2016-10-26

    We report the results of our investigations on the influence of partial substitution of Er and Gd for Dy on the magnetic and magnetoelectric properties of DyFe0.5Cr0.5O3, which is known to be a multiferroic system. Magnetic susceptibility and heat capacity data, apart from confirming the occurrence of magnetic transitions at ~121 and 13 K in DyFe0.5Cr0.5O3, bring out that the lower transition temperature only is suppressed by rare-earth substitution. Multiferroic behavior is found to persist in Dy0.4Ln0.6Fe0.5Cr0.5O3 (Ln  =  Er and Gd). There is an evidence for magnetoelectric coupling in all these materials with qualitative differences in its behavior as the temperature is changed across these two transitions. Remnant electric polarization is observed for all the compounds. The most notable observation is that electric polarization is seen to get enhanced as a result of rare-earth substitution with respect to that in DyFe0.5Cr0.5O3. Interestingly, a similar trend is seen in the magnetocaloric effect, consistent with the existence of magnetoelectric coupling. The results thus provide evidence for the tuning of magnetoelectric coupling by rare-earth substitution in this family of oxides. PMID:27588356

  3. Magnetic Ground States of the Rare-Earth Tripod Kagome Lattice Mg2 RE3 Sb3 O14 (RE =Gd ,Dy ,Er )

    NASA Astrophysics Data System (ADS)

    Dun, Z. L.; Trinh, J.; Li, K.; Lee, M.; Chen, K. W.; Baumbach, R.; Hu, Y. F.; Wang, Y. X.; Choi, E. S.; Shastry, B. S.; Ramirez, A. P.; Zhou, H. D.

    2016-04-01

    We present the structural and magnetic properties of a new compound family, Mg2 RE3 Sb3 O14 (RE =Gd ,Dy ,Er ), with a hitherto unstudied frustrating lattice, the "tripod kagome" structure. Susceptibility (ac, dc) and specific heat exhibit features that are understood within a simple Luttinger-Tisza-type theory. For RE =Gd , we found long-ranged order (LRO) at 1.65 K, which is consistent with a 120° structure, demonstrating the importance of diople interactions for this 2D Heisenberg system. For RE =Dy , LRO at 0.37 K is related to the "kagome spin ice" physics for a 2D system. This result shows that the tripod kagome structure accelerates the transition to LRO predicted for the related pyrochlore systems. For RE =Er , two transitions, at 80 mK and 2.1 K are observed, suggesting the importance of quantum fluctuations for this putative X Y system.

  4. Honeycombs of triangles and magnetic frustration in SrL{sub 2}O{sub 4} (L=Gd, Dy, Ho, Er, Tm, and Yb)

    SciTech Connect

    Karunadasa, H.; Regan, K.A.; Cava, R.J.; Huang, Q.; Lynn, J.W.; Ueland, B.G.; Schiffer, P.

    2005-04-01

    The crystal structures, magnetic order, and susceptibility have been investigated for magnetically frustrated SrDy{sub 2}O{sub 4}, SrHo{sub 2}O{sub 4}, SrEr{sub 2}O{sub 4}, SrTm{sub 2}O{sub 4}, and SrYb{sub 2}O{sub 4}. Powder neutron-diffraction structural refinements reveal columns of LO{sub 6} octahedra that run along one crystallographic direction, with Sr-O polyhedra in the interstices. The lanthanide sublattice displays multiple triangular interconnections: one-dimensional strings form the backbones of four types of chains of lanthanide triangles sharing edges arranged in a honeycomb pattern. This crystal structure produces strong geometric frustration for the magnetic system that is evidenced in both magnetic susceptibility and neutron-scattering data at low temperatures. The susceptibility measurements for the series, including SrGd{sub 2}O{sub 4} for which data are also reported, lack the sharp features characteristic of three-dimensional long-range magnetic ordering. Metamagnetic behavior is observed in the magnetization vs applied field data at 1.8 K for the cases of L=Dy, Er, and Ho. Magnetic neutron-scattering studies for the Dy and Er materials show only very broad magnetic scattering at low temperatures, while the Ho system exhibits long-range two-dimensional order. Any magnetic scattering in the Tm and Yb compounds, if present, was too weak to be detected in these measurements.

  5. Rare-earth transition-metal chalcogenides Ln{sub 3}MGaS{sub 7} (Ln=Nd, Sm, Dy, Er; M=Co, Ni) and Ln{sub 3}MGaSe{sub 7} (Ln=Nd, Sm, Gd, Dy, M=Co; Ln=Nd, Gd, Dy, M=Ni)

    SciTech Connect

    Yin, Wenlong; Shi, Youguo; Kang, Bin; Deng, Jianguo; Yao, Jiyong; Wu, Yicheng

    2014-05-01

    Fifteen new rare-earth transition-metal chalcogenides, Ln{sub 3}MGaS{sub 7} (Ln=Nd, Sm, Dy, Er; M=Co, Ni) and Ln{sub 3}MGaSe{sub 7} (Ln=Nd, Sm, Gd, Dy, M=Co; Ln=Nd, Gd, Dy, M=Ni), have been synthesized by solid state reactions. They are isostructural, adopt Ce{sub 3}Al{sub 1.67}S{sub 7}—related structure type, and crystallize in the non-centrosymmetric hexagonal space group P6{sub 3}. They adopt a three-dimensional framework composed of LnQ{sub 7} monocapped trigonal prisms with the interesting [MQ{sub 3}]{sup 4−} chains and isolated GaQ{sub 4} tetrahedra lying in two sets of channels in the framework. The magnetic susceptibility measurements on Ln{sub 3}CoGaQ{sub 7} (Ln=Dy, Er, Q=S; Ln=Dy, Q=Se) indicate that they are paramagnetic and obey the Curie–Weiss law over the entire experimental temperature, while the magnetic susceptibility of Sm{sub 3}CoGaSe{sub 7} deviates from the Curie–Weiss law as a result of the crystal field splitting. - Graphical abstract: Ln{sub 3}MGaS{sub 7} (Ln=Nd, Sm, Dy, Er; M=Co, Ni) and Ln{sub 3}MGaSe{sub 7} (Ln=Nd, Sm, Gd, Dy, M=Co; Ln=Nd, Gd, Dy, M=Ni) adopt a three-dimensional framework composed of LnQ{sub 7} monocapped trigonal prisms with interesting [MQ{sub 3}]{sup 4−} chains and isolated GaQ{sub 4} tetrahedra lying in two sets of channels in the framework. - Highlights: • New compounds, Ln{sub 3}MGaQ{sub 7} (Ln=rare-earth; M=Co, Ni; Q=S, Se), were synthesized. • They are isostructural and crystallize in the noncentrosymmetric space group P6{sub 3}. • They adopt a three-dimensional framework built by LnQ{sub 7} monocapped trigonal prisms. • Ln{sub 3}CoGaQ{sub 7} (Ln=Dy, Er; Q=S, Se) are paramagnetic and obey the Curie–Weiss law. • The magnetic susceptibility of Sm{sub 3}CoGaSe{sub 7} deviates from the Curie–Weiss law.

  6. Millimeter wave surface resistance of RBa2Cu3O(7-delta) (R=Y,Eu,Dy,Sm,Er) superconductors

    NASA Technical Reports Server (NTRS)

    Miranda, F. A.; Gordon, W. L.; Eck, T. G.; Bhasin, K. B.; Warner, J. D.; Jenkins, K. A.

    1990-01-01

    The measurements are reported of the millimeter wave surface resistance R(sub s) at 58.6 GHz of bulk samples of RBa2Cu3O(7-delta) (R = Y,Eu,Dy,Sm,Er) and of YBa2Cu3O(7-delta) superconducting films, in the temperature range from 20 to 300 K. The bulk samples were prepared by cold pressing the powders of RBa2Cu3O(7-delta) into one in. disks. The powders were prepared by several sinterings in one atmosphere of oxygen at 925 C, with grindings between sinterings, to obtain the superconducting phase. The thin films were deposited on SrTiO3 and LaGaO3 substrates by pulsed laser ablation. Each sample was measured by replacing the end wall of a gold-plated Te sub 013 circular mode copper cavity with the sample and determining the cavity quality factor . From the difference in the Q-factor of the cavity, with and without the sample, the R(sub s) of the sample was determined.

  7. Rare-earth transition-metal chalcogenides Ln3MGaS7 (Ln=Nd, Sm, Dy, Er; M=Co, Ni) and Ln3MGaSe7 (Ln=Nd, Sm, Gd, Dy, M=Co; Ln=Nd, Gd, Dy, M=Ni)

    NASA Astrophysics Data System (ADS)

    Yin, Wenlong; Shi, Youguo; Kang, Bin; Deng, Jianguo; Yao, Jiyong; Wu, Yicheng

    2014-05-01

    Fifteen new rare-earth transition-metal chalcogenides, Ln3MGaS7 (Ln=Nd, Sm, Dy, Er; M=Co, Ni) and Ln3MGaSe7 (Ln=Nd, Sm, Gd, Dy, M=Co; Ln=Nd, Gd, Dy, M=Ni), have been synthesized by solid state reactions. They are isostructural, adopt Ce3Al1.67S7-related structure type, and crystallize in the non-centrosymmetric hexagonal space group P63. They adopt a three-dimensional framework composed of LnQ7 monocapped trigonal prisms with the interesting [MQ3]4- chains and isolated GaQ4 tetrahedra lying in two sets of channels in the framework. The magnetic susceptibility measurements on Ln3CoGaQ7 (Ln=Dy, Er, Q=S; Ln=Dy, Q=Se) indicate that they are paramagnetic and obey the Curie-Weiss law over the entire experimental temperature, while the magnetic susceptibility of Sm3CoGaSe7 deviates from the Curie-Weiss law as a result of the crystal field splitting.

  8. Synthesis, characterisation and properties of rare earth oxyselenides A4O4Se3 (A = Eu, Gd, Tb, Dy, Ho, Er, Yb and Y).

    PubMed

    Tuxworth, Andrew J; Wang, Chun-Hai; Evans, John S O

    2015-02-21

    Rare earth oxyselenides A4O4Se3 (A = Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb and Y) were synthesised using solid state reactions and three new structure types (β, γ, and δ) were observed. A4O4Se3 materials adopt either the α (A = Nd, Sm), β (A = Eu), γ (A = Gd, Tb) or δ (A = Dy, Ho, Er, Yb, Y) structure depending on the rare earth radius. Each structure type contains alternating [A2O2](2+) and Se(2-)/Se2(2-) layers. Different ordered and disordered arrangements of Se(2-) and [Se-Se](2-) give the Se layer flexibility and lead to the four different structure types observed. The volume coefficients of expansion for A4O4Se3 ranged from +1.746(9) × 10(-5) to +2.237(3) × 10(-5) K(-1) from 12 to 300 K; no structural phase transitions were observed in this temperature range. Diffuse reflection spectra show A4O4Se3 are semiconductors with band gap Eg 1.02-1.46 eV. Gd4O4Se3, Dy4O4Se3, and Tb4O4Se3 samples show antiferromagnetic ordering with Néel temperature, TN, of 7-9 K. DFT calculations confirm the two different valence states of Se(2-) and Se2(2-) in Eu4O4Se3. PMID:25581725

  9. Phases observed at 900-1100 degree C in the binary Ln-Ba-O systems for Ln = Dy, Ho, Er, Tm, and Yb

    SciTech Connect

    Hodorowicz, E.; Hodorowicz, S.A.; Eick, H.A. )

    1990-02-01

    The compounds Ln{sub 2}Ba{sub 2}O{sub 5}, Ln{sub 2}Ba{sub 4}O{sub 7}, and Ln{sub 4}Ba{sub 3}O{sub 9}, for Ln = Dy, Ho, Er, Tm, and Yb, have been prepared and characterized by X-ray powder diffraction. Phase interrelationships were established as a function of temperature by quenching specimens annealed at 900-l 100{degree}C. Comparable Ln = Tb phases could not be prepared. Lattice parameters are presented for all phases observed.

  10. The structure of new nickel(I) oxides: LnSr 5Ni 3O 8 (Ln = Y, Dy, Ho, Er and Tm)

    NASA Astrophysics Data System (ADS)

    James, M.; Attfield, J. P.

    1994-12-01

    Stoichiometric oxides of 3d 9 nickel(I), LnSr 5Ni 3O 8 (Ln = Y, Dy, Ho, Er and Tm), have been prepared through the hydrogen reduction of LnSr 5Ni 3O 11, resulting in a change from a tetragonal K 2NiF 4 type structure to an orthorhombic Sr 2CuO 3 arrangement in which {1}/{3} of the bridging oxygen atoms are missing from chains of apex-linked nickel oxide square planes.

  11. Critical behavior in spin-reorientation phase transitions: (Er sub x R sub 1 minus x ) sub 2 Fe sub 14 B ( R =Nd, Dy) magnets

    SciTech Connect

    del Moral, A.; Ibarra, M.R.; Marquina, C.; Arnaudas, J.I.; Algarabel, P.A. )

    1989-10-01

    The critical behavior of spin-reorientation phase transitions in the hard magnetic intermetallics (Er{sub {ital x}}{ital R}{sub 1{minus}x}){sub 2}Fe{sub 14}B ({ital R}=Dy and Nd) has been studied with ac low-field susceptibility, {chi}{sub {ital H}}, and cone-angle measurements. A simple model for scaling the low-field susceptibility has been developed and applied to the present series of compounds. The critical exponents for {chi}{sub {ital H}} have been determined for some well-behaved compounds.

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

    PubMed

    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. PMID:23977903

  13. Magnetic Ground States of the Rare-Earth Tripod Kagome Lattice Mg_{2}RE_{3}Sb_{3}O_{14} (RE=Gd,Dy,Er).

    PubMed

    Dun, Z L; Trinh, J; Li, K; Lee, M; Chen, K W; Baumbach, R; Hu, Y F; Wang, Y X; Choi, E S; Shastry, B S; Ramirez, A P; Zhou, H D

    2016-04-15

    We present the structural and magnetic properties of a new compound family, Mg_{2}RE_{3}Sb_{3}O_{14} (RE=Gd,Dy,Er), with a hitherto unstudied frustrating lattice, the "tripod kagome" structure. Susceptibility (ac, dc) and specific heat exhibit features that are understood within a simple Luttinger-Tisza-type theory. For RE=Gd, we found long-ranged order (LRO) at 1.65 K, which is consistent with a 120° structure, demonstrating the importance of diople interactions for this 2D Heisenberg system. For RE=Dy, LRO at 0.37 K is related to the "kagome spin ice" physics for a 2D system. This result shows that the tripod kagome structure accelerates the transition to LRO predicted for the related pyrochlore systems. For RE=Er, two transitions, at 80 mK and 2.1 K are observed, suggesting the importance of quantum fluctuations for this putative XY system. PMID:27127982

  14. Magnetic properties of R2Co15Al2 compounds with R=Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm

    NASA Astrophysics Data System (ADS)

    Shen, Bao-gen; Cheng, Zhao-hua; Zhang, Shao-ying; Wang, Jing-yun; Liang, Bing; Zhang, Hong-wei; Zhan, Wen-shan

    1999-03-01

    An investigation of the structure and the magnetic anisotropy of R2Co15Al2 (R=Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm) compounds has been performed by means of x-ray diffraction and magnetization measurements. X-ray diffraction shows the prepared compounds to be single phase, having the hexagonal Th2Ni17-type structure for R=Y, Ho, Er, and Tm and the rhombohedral Th2Zn17-type structure for R=Ce, Pr, Nd, Gd, Tb, and Dy. Except for the Ce compound, the unit-cell volumes of R2Co15Al2 compounds decrease in accordance with the lanthanide contraction. Substitution of Al for Co in R2Co17 leads to a decrease of the saturation magnetization at 1.5 K and Curie temperature. The exchange-coupling constants JCo-Co and JR-Co have been calculated by using the method based on magnetic ordering temperature. It is found that the JR-Co has a small dependence on the R elements and is almost not affected by the Al substitution. The Ce compound is found to exhibit an anomalous lattice parameter and magnetic characteristic, which are relative to the mixed-valence behavior of the Ce ion. X-ray diffraction measurements on magnetically aligned R2Co15Al2 powders show that the compounds with R=Pr, Nd, Gd, Tb, Dy, and Ho have an easy-plane type of magnetic anisotropy, whereas the compounds with R=Y, Ce, Sm, Er, and Tm exhibit an easy-axis type of magnetic anisotropy at room temperature. The compounds R2Co15Al2 with R=Pr and Ho exhibit a spin-reorientation transition and the spin-reorientation temperature is found to be 531 and 431 K, respectively. A strong uniaxial anisotropy is observed in Sm2Co15Al2 compound with a magnetocrystalline anisotropy field of 84 kOe at room temperature.

  15. On the absence of rotational levels for J{sup π}K = 0{sup +}0{sub 2} and 2{sup +}2{sub 2} nonrotational states in {sup 164}Dy and {sup 166}Er

    SciTech Connect

    Govor, L. I. Demidov, A. M.; Kurkin, V. A.; Mikhailov, I. V.

    2015-03-15

    Various reasons for the absence of rotational levels for J{sup π}K = 0{sup +}0{sub 2} and 2{sup +}2{sub 2} nonrotational states in {sup 164}Dy and {sup 166}Er are considered. Preference is given to the effect of the excitation of an anharmonic two-phonon state in pair vibrations of the superconducting type.

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

    SciTech Connect

    Wong-Ng, W.; Yan, Y.; Liu, G.; Xie, W.; Tritt, T.; Kaduk, J.; Thomas, E.

    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.

  17. Heat capacities, magnetic properties, and resistivities of ternary RPdBi alloys where R = La, Nd, Gd, Dy, Er, and Lu

    SciTech Connect

    Riedemann, T.M.

    1996-05-01

    Over the past four and a half decades research on the rare earths, their compounds, and their alloys has yielded significant insights into the nature of materials. The rare earths can be used to systematically study a series of alloys or compounds. Magnetic ordering, crystalline fields, spin fluctuations, the magnetocaloric effect, and magnetostriction are a small sample of phenomena studied that are exhibited by the rare earth family. A significant portion of research has been conducted on the abundant RM{sub 2} and RM phases, where R is the rare earth and M is a transition metal. The natural progression of science has led to the study of related RMX ternary phases, where X is either another transition metal or semimetal. There are now over 1,000 known RMX phases. The focus of this study is on RPdBi where R = La, Nd, Gd, Dy, Er, and Lu. Their heat capacities, magnetic properties, and resistivities are studied.

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

    PubMed

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

    2005-05-01

    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. PMID:15847410

  19. Ab initio calculation of local magnetic moments and the crystal field in scrR2Fe14B (scrR=Gd, Tb, Dy, Ho, and Er)

    NASA Astrophysics Data System (ADS)

    Hummler, K.; Fähnle, M.

    1992-02-01

    The local magnetic moments and the valence contribution to the crystal-field parameter A02 at the rare-earth sites are calculated for scrR2Fe14B with scrR=Gd, Tb, Dy, Ho, and Er within the framework of the linear-muffin-tin-orbital theory and the local-spin-density approximation. Thereby, the 4f moments of scrR are calculated by the Russel-Saunders scheme, but the radial 4f spin density was part of the self-consistent density-functional calculation. The local moments as well as A02 averaged over the two crystallographically inequivalent scrR sites remain remarkably constant across the series.

  20. Synthesis and characterization of ultrafine Ln{sub 2}Ti{sub 2}O{sub 7} (Ln = Sm, Gd, Dy, Er) pyrochlore oxides by stearic acid method

    SciTech Connect

    Zhang Weiguang; Zhang Lili; Zhong Hui; Lu Lude; Yang Xujie; Wang Xin

    2010-02-15

    Stearic acid method (SAM) was developed to synthesize series of pyrochlore Ln{sub 2}Ti{sub 2}O{sub 7} (Ln = Sm, Gd, Dy, Er) nanocrystals. The synthesis process was monitored by X-ray diffraction, Thermal-gravimetric-differential thermal analysis and Fourier Transform InfraRed methods. Comparing with traditional solid-state reaction (SSR), Ln{sub 2}Ti{sub 2}O{sub 7} can be synthesized at relatively low temperature (700-800 deg. C) with shortened reaction time (2-4 h). The average particle size of Ln{sub 2}Ti{sub 2}O{sub 7} was greatly reduced (ca. 40 nm) and the BET surface area was increased (ca. 12 m{sup 2}/g) by using SAM. From the X-ray diffraction patterns, we found that Ln has an effect on the crystal structure of Ln{sub 2}Ti{sub 2}O{sub 7}, every lattice peak shifted to larger angle slightly with the increasing atomic number of Ln. Also, the lattice constant of Ln{sub 2}Ti{sub 2}O{sub 7} was calculated by Jade.5 and found it decreased along with the decrease of ionic radius of Ln{sup 3+}. The morphology of obtained Ln{sub 2}Ti{sub 2}O{sub 7} was determined by transmission electron microscopy technique. Results showed that the obtained Ln{sub 2}Ti{sub 2}O{sub 7} were all square-like and the interplanar distance of Ln{sub 2}Ti{sub 2}O{sub 7} (Ln = Sm, Gd, Dy, Er) according to (111) plane was 0.65, 0.64, 0.63, and 0.62 nm respectively, which was measured from High Resolution Transmission Electron Microscopy images. Possible reason for this phenomenon was presented.

  1. Crystal Structures and Reference Powder Patterns of BaR2ZnO5 (R = La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, and Tm)

    PubMed Central

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

    1999-01-01

    Reference x-ray powder patterns and the crystal structures of the lanthanide compounds, BaR2ZnO5, in which R = La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, or Tm, were determined by the x-ray Rietveld refinement technique. A structural trend was confirmed for this series of compounds. The compounds with smaller ionic radii (R = Sm, Eu, Gd, Dy, Ho, Y, Er, or Tm) are isostructural to the orthorhombic “green phase” (BaY2CuO5). The lattice parameters for compounds with R = Tm to Sm range from a = 7.01855(9) Å to 7.20452(14) Å, b = 12.25445 (17) Å to 12.5882(2) Å, and c = 5.6786(14) Å to 5.81218(11) Å, respectively. R is sevenfold coordinated inside a monocapped trigonal prism. These prisms share edges to form wave-like chains parallel to the long b-axis. The BaR2ZnO5 compounds which contain larger size R (La and Nd) crystallize in the tetragonal space group I4/mcm. The lattice parameters are a = 6.90982(10) and c = 11.5977(2) Å for BaLa2ZnO5, and a = 6.75979(5) Å and c = 11.54560(12) Å for BaNd2ZnO5. The structure consists of ZnO4 tetrahedra (instead of planar CuO4 groups as found in BaR2CuO5) with 10-fold coordinated bicapped square prismatic Ba and 8-fold coordinated bicapped trigonal prismatic R ions between them. The reference x-ray powder patterns will be submitted to the Powder Diffraction File (PDF).

  2. Ternary rare earth metal boride carbides containing two-dimensional boron-carbon network: The crystal and electronic structure of R{sub 2}B{sub 4}C (R=Tb, Dy, Ho, Er)

    SciTech Connect

    Babizhetskyy, Volodymyr Zheng Chong; Mattausch, Hansjuergen; Simon, Arndt

    2007-12-15

    The ternary rare earth boride carbides R{sub 2}B{sub 4}C (R=Tb, Dy, Ho, Er) have been synthesized by reacting the elements at temperatures between 1800 and 2000K. The crystal structure of Dy{sub 2}B{sub 4}C has been determined from single-crystal X-ray diffraction data. It crystallizes in a new structure type in the orthorhombic space group Immm (a=3.2772(6) A, b=6.567(2) A, c=7.542(1) A, Z=2, R1=0.035 (wR{sub 2}=0.10) for 224 reflections with I{sub o}>2{sigma}(I{sub o})). Boron atoms form infinite chains of fused B{sub 6} rings in [100] joined with carbon atoms into planar, two-dimensional networks which alternate with planar sheets of rare earth metal atoms. The electronic structure of Dy{sub 2}B{sub 4}C was also analyzed using the tight-binding extended Hueckel method. - Graphical abstract: Dy{sub 2}B{sub 4}C crystallizes a new structure type where planar 6{sup 3}-Dy metal atom layers alternate with planar non-metal layers consisting of ribbons of fused B{sub 6} hexagons bridged by carbon atoms. Isostructural analogues with Tb, Ho and Er have also been characterized.

  3. Powder X-Ray Reference Patterns of Sr2RGaCu2Oy (R = Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, and Y)

    PubMed Central

    Wong-Ng, W.; Kaduk, J. A.; Levin, I.; Greenwood, W.; Dillingham, J.

    2001-01-01

    X-Ray Rietveld refinements were conducted on a series of eleven lanthanide phases, Sr2RGaCu2Oy (2112 phase, R = Pr, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, Tm, and Yb) that are structurally related to the high Tc superconductor Ba2YCu3O7 (213). In the 2112 structure, instead of square planar Cu-O chains, tetrahedral GaO4 chains were found to run in a zig-zag fashion along the diagonal of the basal 213 ab-direction. Reference powder patterns for these compounds were prepared by using the Rietveld decomposition technique. The unit cell volume of these compounds follows the expected trend of the lanthanide contraction. The lattice parameters range from a = 22.9694(3) Å, b = 5.5587(2) Å, and c = 5.44743(7) Å for R = Pr, to a = 22.8059(2) Å, b = 5.46031(5) Å, and c = 5.37773(5) Å for R = Yb. An electon diffraction study of the Sm- and Er-analogs showed characteristic diffuse streaks along the b-axis, suggesting some disorder within the GaO4 chains.

  4. Preparation, Characterization, and Ionic Transport Properties of Nanoscale Ln2Zr2O7 (Ln = Ce, Pr, Nd, Sm, Gd, Dy, Er, and Yb) Energy Materials

    NASA Astrophysics Data System (ADS)

    Solomon, Sam; George, Aneesh; Thomas, Jijimon Kumpakkattu; John, Annamma

    2015-01-01

    Nanoparticles of lanthanide (Ln)-based zirconates have been prepared through the autoignited combustion technique. The structure of the system was analyzed by powder x-ray diffraction and vibrational spectroscopic tools. The compounds with Ln = Ce, Pr, Nd, Sm, and Gd have pyrochlore cubic structure, whereas those with Ln = Dy, Er, and Yb possess anion-deficient disordered cubic fluorite structure. The optical properties of the powder were analyzed using ultraviolet-visible spectroscopy. Pellets of the compounds were sintered in the range from 1325°C to 1530°C for 2 h. The surface morphology of sintered Nd2Zr2O7 was analyzed by scanning electron microscopy. Impedance spectroscopic studies of the samples were carried out at different temperatures. The conductivity increased to the order of 10-2 S/m at 750°C, and the highest conductivity of 13.21 × 10-2 S/m was obtained for Er2Zr2O7. All samples of this system are suitable candidates for fabrication of electrolytes for use in solid oxide fuel cells, particularly at moderate temperatures.

  5. Ternary rare earth metal boride carbides containing two-dimensional boron carbon network: The crystal and electronic structure of R2B4C (R=Tb, Dy, Ho, Er)

    NASA Astrophysics Data System (ADS)

    Babizhetskyy, Volodymyr; Zheng, Chong; Mattausch, Hansjürgen; Simon, Arndt

    2007-12-01

    The ternary rare earth boride carbides R2B4C (R=Tb, Dy, Ho, Er) have been synthesized by reacting the elements at temperatures between 1800 and 2000K. The crystal structure of Dy2B4C has been determined from single-crystal X-ray diffraction data. It crystallizes in a new structure type in the orthorhombic space group Immm (a=3.2772(6) Å, b=6.567(2) Å, c=7.542(1) Å, Z=2, R1=0.035 (wR2=0.10) for 224 reflections with Io>2σ(Io)). Boron atoms form infinite chains of fused B6 rings in [100] joined with carbon atoms into planar, two-dimensional networks which alternate with planar sheets of rare earth metal atoms. The electronic structure of Dy2B4C was also analyzed using the tight-binding extended Hückel method.

  6. yt graphics interface for MOCASSIN

    NASA Astrophysics Data System (ADS)

    Gesicki, K.; Kowalik, K.

    2014-04-01

    The YT PROJECT, written by working astrophysicists, designed for pragmatic and detailed data analysis and visualizations, already applied for hydrodynamical and cosmological simulations, has been adopted for models obtained from the "Mocassin" code. The poster advertises this Python package for 3D analysis of PNe.

  7. Rare earth metal-rich indides RE14Rh 3-xIn 3 ( RE=Y, Dy, Ho, Er, Tm, Lu)

    NASA Astrophysics Data System (ADS)

    Zaremba, Roman; Pöttgen, Rainer

    2007-09-01

    The rare earth ( RE) metal-rich indides RE14Rh 3-xIn 3 ( RE=Y, Dy, Ho, Er, Tm, Lu) can be synthesized from the elements by arc-melting or induction melting in tantalum crucibles. They were investigated by X-ray diffraction on powders and single crystals: Lu 14Co 3In 3 type, space group P4 2/ nmc, Z=4, a=961.7(1), c=2335.5(5) pm, w R2=0.052, 2047 F2 values, 62 variables for Y 14Rh 3In 3, a=956.8(1), c=2322.5(5) pm, w R2=0.068, 1730 F2 values, 63 variables for Dy 14Rh 2.89(1)In 3, a=952.4(1), c=2309.2(5) pm, w R2=0.041, 1706 F2 values, 63 variables for Ho 14Rh 2.85(1)In 3, a=948.6(1), c=2302.8(5) pm, w R2=0.053, 1977 F2 values, 63 variables for Er 14Rh 2.86(1)In 3, a=943.8(1), c=2291.5(5) pm, w R2=0.065, 1936 F2 values, 63 variables for Tm 14Rh 2.89(1)In 3, and a=937.8(1), c=2276.5(5) pm, w R2=0.050, 1637 F2 values, 63 variables for Lu 14Rh 2.74(1)In 3. Except Yb 14Rh 3In 3, the 8 g Rh1 sites show small defects. Striking structural motifs are rhodium-centered trigonal prisms formed by the RE atoms with comparatively short Rh- RE distances (271-284 pm in Y 14Rh 3In 3). These prisms are condensed via common corners and edges building two-dimensional polyhedral units. Both crystallographically independent indium sites show distorted icosahedral coordination. The icosahedra around In2 are interpenetrating, leading to In2-In2 pairs (309 pm in Y 14Rh 3In 3).

  8. Analysis of the intrinsic magnetic properties of R{sub 2}Fe{sub 17} single crystals (R=Y, Dy, Ho, Er)

    SciTech Connect

    Garcia-Landa, B.; Algarabel, P.A.; Ibarra, M.R.; Kayzel, F.E.; Franse, J.J.

    1997-04-01

    The magnetic behavior of some R{sub 2}Fe{sub 17} single crystals have been analyzed quantitatively in a wide temperature range, using a two-sublattice approximation for the magnetic structure and taking into account isotropic exchange and single-ion crystal-field interactions. The 3d sublattice behavior has been described phenomenologically, from the study of the experimental magnetization results in a Y{sub 2}Fe{sub 17} single crystal. The parameters A{sub 2}{sup 0}, A{sub 4}{sup 0}, A{sub 6}{sup 0}, A{sub 6}{sup 6}, describing the crystal-field interaction in the different R{sub 2}Fe{sub 17} compounds (R=Er, Dy, Ho) have been determined. The calculated magnetic behavior shows good agreement with experimental magnetization results in the temperature range 4.2 to 300 K, demonstrating the reliability of the determined parameters. {copyright} {ital 1997} {ital The American Physical Society}

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

    PubMed

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

    2013-08-14

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

  10. 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)

    NASA Astrophysics Data System (ADS)

    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

  11. Rare earth metal-rich indides RE{sub 14}Rh{sub 3-x}In{sub 3} (RE=Y, Dy, Ho, Er, Tm, Lu)

    SciTech Connect

    Zaremba, Roman; Poettgen, Rainer

    2007-09-15

    The rare earth (RE) metal-rich indides RE{sub 14}Rh{sub 3-x}In{sub 3} (RE=Y, Dy, Ho, Er, Tm, Lu) can be synthesized from the elements by arc-melting or induction melting in tantalum crucibles. They were investigated by X-ray diffraction on powders and single crystals: Lu{sub 14}Co{sub 3}In{sub 3} type, space group P4{sub 2}/nmc, Z=4, a=961.7(1), c=2335.5(5) pm, wR2=0.052, 2047 F{sup 2} values, 62 variables for Y{sub 14}Rh{sub 3}In{sub 3}, a=956.8(1), c=2322.5(5) pm, wR2=0.068, 1730 F{sup 2} values, 63 variables for Dy{sub 14}Rh{sub 2.89(1)}In{sub 3}, a=952.4(1), c=2309.2(5) pm, wR2=0.041, 1706 F{sup 2} values, 63 variables for Ho{sub 14}Rh{sub 2.85(1)}In{sub 3}, a=948.6(1), c=2302.8(5) pm, wR2=0.053, 1977 F{sup 2} values, 63 variables for Er{sub 14}Rh{sub 2.86(1)}In{sub 3}, a=943.8(1), c=2291.5(5) pm, wR2=0.065, 1936 F{sup 2} values, 63 variables for Tm{sub 14}Rh{sub 2.89(1)}In{sub 3}, and a=937.8(1), c=2276.5(5) pm, wR2=0.050, 1637 F{sup 2} values, 63 variables for Lu{sub 14}Rh{sub 2.74(1)}In{sub 3}. Except Yb{sub 14}Rh{sub 3}In{sub 3}, the 8g Rh1 sites show small defects. Striking structural motifs are rhodium-centered trigonal prisms formed by the RE atoms with comparatively short Rh-RE distances (271-284 pm in Y{sub 14}Rh{sub 3}In{sub 3}). These prisms are condensed via common corners and edges building two-dimensional polyhedral units. Both crystallographically independent indium sites show distorted icosahedral coordination. The icosahedra around In2 are interpenetrating, leading to In2-In2 pairs (309 pm in Y{sub 14}Rh{sub 3}In{sub 3}). - Graphical abstract: Condensed [RhRE{sub 6}] trigonal prisms in RE{sub 14}Rh{sub 3}In{sub 3} indides.

  12. Srystal structure and physical properties of the new ternary antimonides Ln{sub 3}Pd{sub 8}Sb{sub 4} (Ln=Y, Gd, Tb, Dy, Ho, Er, Tm)

    SciTech Connect

    Zelinska, Mariya; Oryshchyn, Stepan; Zhak, Olga; Pivan, Jean-Yves; Potel, Michel; Tougait, Olivier; Noel, Henri; Kaczorowski, Dariusz

    2010-09-15

    The ternary antimonides Ln{sub 3}Pd{sub 8}Sb{sub 4} (Ln=Y, Gd, Tb, Dy, Ho, Er, Tm) have been synthesized for the first time. The crystal structure of Er{sub 3}Pd{sub 8}Sb{sub 4} has been solved from the X-ray single crystal data: own type structure, space group Fm3-bar m, a=1.3050(1) nm, R{sub F}=0.0484, R{sub W}=0.0524 for 17 free parameters and 401 reflections with F(hkl)>4{sigma}(F). The structure of Er{sub 3}Pd{sub 8}Sb{sub 4} can be viewed as a ternary ordered version of the Sc{sub 11}Ir{sub 4}-type. The lattice parameters of the isotypic compounds Ln{sub 3}Pd{sub 8}Sb{sub 4} (Ln=Y, Gd, Tb, Dy, Ho, Tm) have been refined from the X-ray powder diffraction data. The magnetic and electrical properties of the compounds Ln{sub 3}Pd{sub 8}Sb{sub 4} (Ln=Tb, Ho, Er) have been studied down to 1.75 K. The Ho- and Er-based phases have been found to order antiferromagnetically at 2.5 and 2.0 K, respectively. For all three compounds, the magnetic susceptibility follows in the paramagnetic region the Curie-Weiss behavior with the effective magnetic moments close to the respective free trivalent ion values. All three antimonides studied exhibit metallic character of the electrical conductivity. - Graphical abstract: Projection of the crystal structure of Er{sub 3}Pd{sub 8}Sb{sub 4} onto XY plane and the coordination polyhedra of all the atoms.

  13. Preparation and Dielectric Measurements of the Rare Earth Green Phases R2BaCuO(5-x) (R = Y, Sm, Gd, Dy, Ho, Er, Yb)

    NASA Technical Reports Server (NTRS)

    Gonzalez-Titman, Carlos

    1994-01-01

    It has been demonstrated that R2BaCuO(5-x) (R = Y, Sm, Gd, Dy, Ho, Er, Yb) does not undergo significant densification unless the sintering temperatures are near the incongruent melting point or the sintering times are long. Good quality powders of Y2BaCuO(5-x) have been synthesized by using oxide raw materials or precursors such as acetates and nitrates. The acetates- and the nitrates-derived yttrium green phase resulted in finer particle sizes, acceptable dielectric properties and lower melting temperatures than those processed via oxide raw materials. The hot pressing technique has been employed to produce a dense R2BaCuO(5-x) (R=Y,Gd) substrate with satisfactory dielectric properties. Reactivity to reducing conditions, i.e. graphite die, limited the optimization of the properties. A high sensitivity to the annealing atmosphere has been demonstrated in Y2BaCuO,.,,. Oxygen treatment at 950 OC has been shown to improve the dielectric properties while treatment in nitrogen, at the same temperature, degraded desirable properties. A high sensitivity to the annealing atmosphere has been demonstrated in Y2BaCuO(5-x). Oxygen treatment at 950 C has been shown to improve the dielectric properties while treatment in nitrogen, at the same temperature, degraded desirable properties. The dielectric constants of the rare earth green phases R2BaCuO(5-x) were found to be low. Relaxation peaks were detected at low temperatures (T less than 150 K) and at high temperatures (150 less than T greater than 420 K). The dielectric losses and conductivities at 77 K were measured to be in the range of 10(exp -4) and 10(exp -12) (Omega-cm)(exp -1), respectively. Many parameters were found to exhibit dependencies on the rare earth cation sizes.

  14. Indium flux synthesis of RE4Ni2InGe4 (RE = Dy, Ho, Er, and Tm): an ordered quaternary variation on the binary phase Mg5Si6.

    PubMed

    Salvador, James R; Kanatzidis, Mercouri G

    2006-09-01

    The quaternary compounds RE4Ni2InGe4 (RE = Dy, Ho, Er, and Tm) were obtained as large single crystals in high yields from reactions run in liquid In. The title compounds crystallize in the monoclinic C2/m space group with the Mg(5)Si(6) structure type with lattice parameters a = 15.420(2) A, b = 4.2224(7) A, c = 7.0191(11) A, and beta = 108.589(2) degrees for Dy4Ni2InGe4, a = 15.373(4) A, b = 4.2101(9) A, c = 6.9935(15) A, and beta = 108.600(3) degrees for Ho4Ni2InGe4, a = 15.334(7) A, b = 4.1937(19) A, c = 6.975(3) A, and beta =108.472(7) degrees for Er4Ni2InGe4, and a = 15.253(2) A, b = 4.1747(6) A, c = 6.9460(9) A, and beta = 108.535(2) degrees for Tm4Ni2InGe4. RE4Ni2InGe4 formed in liquid In from a melt that was rich in the rare-earth component. These compounds are polar intermetallic phases with a cationic rare-earth substructure embedded in a transition metal and main group matrix. The rare-earth atoms form a highly condensed network, leading to interatomic distances that are similar to those found in the elemental lanthanides themselves. The Dy and Ho analogues display two maxima in the susceptibility, suggesting antiferromagnetic ordering behavior and an accompanying spin reorientation. The Er analogue shows only one maximum in the susceptibility, and no magnetic ordering was observed for the Tm compound down to 2 K. PMID:16933908

  15. Synthesizing Understanding from Data with yt

    NASA Astrophysics Data System (ADS)

    Turk, Matthew; yt project

    2016-01-01

    The yt project (yt-project.org) is a community-developed platform for constructing and executing analysis tasks on volumetric data. While principally applied to astrophysical simulation data, it has applications in other domains, and is a mechanism for abstracting and applying algorithms independent of the discretization (point/particle, grid, unstructured mesh) mechanism of the underlying data. In this talk, I will demonstrate its functionality for analyzing and visualizing grid, particle (SPH) and octree data, and describe its applications within a broad spectrum of astrophysical problems. Of particular importance in the methodology for development of yt is its community-based nature, with needs-driven development supporting much of its functionality; this talk will conclude with descriptions of the community of practice that surrounds yt, and the mechanisms by which this community supports and is supported by the technical aspects of yt.

  16. Up/down conversion luminescence and charge compensation investigation of Ca0.5Y1-x(WO4)2:xLn3+ (Ln = Pr, Sm, Eu, Tb, Dy, Yb/Er) phosphors

    NASA Astrophysics Data System (ADS)

    Mahalingam, Venkatakrishnan; Thirumalai, Jagannathan; Krishnan, Rajagopalan; Mantha, Srinivas

    2016-01-01

    Microstructures of Ca0.5Y(1-x)(WO4)2:xLn3+ (Ln = Pr, Sm, Eu, Tb, Dy, Yb/Er) phosphors were prepared via the solid-state reaction method. X-ray diffraction, scanning electron microscopy and photoluminescence were used to characterize the prepared phosphor samples. The results reveal that the phosphor samples have single phase scheelite structures with tetragonal symmetry of I41/a. The down/up conversion photoluminescence of the Ca0.5Y(1-x)(WO4)2:xLn3+ (Ln = Pr, Sm, Eu, Tb, Dy, Yb/Er) phosphors properties reveal characteristic visible emissions. The energy transfer process, fluorescence lifetime and color coordinates are discussed in detail. Furthermore, the phosphor Ca0.5Y(1-x)(WO4)2:xPr3+ co-doped with alkali chlorides shows the enhancement of luminescence, which was found in the sodium chloride co-doped powder phosphor. The photometric characteristics indicate the suitability of the inorganic powder phosphors for solid-state lighting and display applications.

  17. Effect of dilution in the cobalt subsystem on phase transitions in rare-earth cobaltites RBaCo4- x M x O7 (R = Dy-Er, Yb, Y; M = Al, Zn)

    NASA Astrophysics Data System (ADS)

    Kazei, Z. A.; Snegirev, V. V.; Kozeeva, L. P.; Kameneva, M. Yu.

    2016-01-01

    We have experimentally studied the structural and elastic characteristics of rare-earth cobaltites RBaCo4- x M x O7 (R = Dy-Er, Yb, Y), in which cobalt ions are partly substituted by diamagnetic Al or Zn ions. It was found that small substitution of Co3+ ions by Al3+ ions in the YbRBaCo4- x M x O7 system ( x = 0.1, 0.2, 0.5) leads to a rapid decrease and smearing of Δ E( T) /E 0 anomalies of the Young's modulus in the region of the structural phase transition, which is accompanied by increasing hysteresis. Pure rare-earth cobaltites RBaCo4O7 (R = Dy-Er, Y) exhibit a correlation between the room-temperature structure distortion and hysteresis on the Δ E( T)/ E 0 curve in a temperature interval of 80-280 K. In Zn-substituted cobaltites RBaCoZn3O7, both the hysteresis and Δ E( T)/ E 0 anomalies disappear, as do low-temperature sound absorption maxima. This behavior is evidence of the suppression of structural and magnetic phase transitions and the retention of only short-range correlations of the order parameter in Zn-substituted samples.

  18. Facile synthesis and luminescence properties of Y2O3:Ln(3+) (Ln(3+) = Eu(3+), Tb(3+), Dy(3+), Sm(3+), Er(3+), Ho(3+), Tm(3+), Yb(3+)/Er(3+), Yb(3+)/Tm(3+), Yb(3+)/Ho(3+)) microspheres.

    PubMed

    Xu, Zhenhe; Zhao, Qian; Ren, Baoyi; You, Lixin; Sun, Yaguang

    2014-08-01

    Multicolor and monodisperse Y2O3:Ln(3+) (Ln(3+) = Eu(3+), Tb(3+), Dy(3+), Sm(3+), Er(3+), Ho(3+), Tm(3+), Yb(3+)/Er(3+), Yb(3+)/Ho(3+)) microspheres were prepared through a facile urea-assisted homogeneous precipitation method followed by a subsequent calcination process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrum (EDS), Fourier transformed infrared (FT-IR), thermogravimetric analysis (TGA), photoluminescence (PL) and cathodoluminescence (CL) spectra were employed to characterize the samples. The XRD results reveal that the as-prepared spheres can be well indexed to cubic Y2O3 phase with high purity. The SEM and TEM images show the obtained Y2O3:Ln(3+) samples consist of regular nanospheres with the mean diameter of 350 nm. And the possible formation mechanism is also proposed. Upon ultraviolet and low-voltage electron beams excitation, Y2O3:Ln(3+) (Ln(3+) = Eu(3+), Tb(3+), Dy(3+), Sm(3+), Er(3+), Ho(3+), Tm(3+)) samples exhibit respective bright red (Eu(3+), (5)D0 --> (7)F2), green (Tb(3+), (5)D4 --> (7)F5), blue (Dy(3+), (4)F9/2 --> (6)H13/2), yellow (Sm(3+), (4)G5/2 --> (6)H7/2), green (Er(3+), (4)S3/2 --> (4)I15/2), green (Ho(3+), (5)S2 --> (5)I8), blue (Tm(3+), (1)D2 --> (3)F4) down-conversion (DC) emissions. Under 980 nm NIR irradiation, Y2O3:Ln(3+) (Ln(3+) = Yb(3+)/Er(3+), Yb(3+)/Tm(3+) and Yb(3+)/Ho(3+)) exhibit characteristic up-conversion (UC) emissions of green (Er(3+), (2)H11/2, (4)S3/2, (2)H11/2 --> (4)I5/2), blue (Tm(3+), (1)G4 --> (3)H6) and green (Ho(3+), (5)F4, (5)S2 --> (5)I8), respectively. These merits of multicolor emissions in the visible region endow this kind of material with potential applications in the field of light display systems, lasers, and optoelectronic devices. PMID:25936002

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

    SciTech Connect

    Gribanov, Alexander; Grytsiv, Andriy; Rogl, Peter; Seropegin, Yurii; Giester, Gerald

    2009-07-15

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

  20. Magnetic properties of the charge density wave compounds RTe3, R=Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er & Tm

    SciTech Connect

    Ru, N.; Chu, J.-H.; Fisher, I.R.; /Stanford U., Geballe Lab.

    2009-12-14

    The antiferromagnetic transition is investigated in the rare-earth (R) tritelluride RTe{sub 3} family of charge density wave (CDW) compounds via specific heat, magnetization and resistivity measurements. Observation of the opening of a superzone gap in the resistivity of DyTe{sub 3} indicates that additional nesting of the reconstructed Fermi surface in the CDW state plays an important role in determining the magnetic structure.

  1. Systematic Study of a Family of Butterfly-Like {M2Ln2} Molecular Magnets (M = Mg(II), Mn(III), Co(II), Ni(II), and Cu(II); Ln = Y(III), Gd(III), Tb(III), Dy(III), Ho(III), and Er(III)).

    PubMed

    Moreno Pineda, Eufemio; Chilton, Nicholas F; Tuna, Floriana; Winpenny, Richard E P; McInnes, Eric J L

    2015-06-15

    A family of 3d-4f [M(II)2Ln(III)2(μ3-OH)2(O2C(t)Bu)10](2-) "butterflies" (where M(II) = Mg, Co, Ni, and Cu; Ln(III) = Y, Gd, Tb, Dy, Ho, and Er) and [Mn(III)2Ln(III)2(μ3-O)2(O2C(t)Bu)10](2-) molecules (where Ln(III) = Y, Gd, Tb, Dy, Ho, and Er) has been synthesized and characterized through single-crystal X-ray diffraction, SQUID magnetometry, and ab initio calculations. All dysprosium- and some erbium-containing tetramers showed frequency-dependent maxima in the out-of-phase component of the susceptibility associated with slow relaxation of magnetization, and hence, they are single-molecule magnets (SMMs). AC susceptibility measurements have shown that the SMM behavior is entirely intrinsic to the Dy and Er sites and the magnitude of the energy barrier is influenced by the interactions between the 4f and the 3d metal. A trend is observed between the strength of the 3d-4f exchange interaction between and the maximum observed in the χ″M(T). PMID:26016421

  2. A family of 12-azametallacrown-4 structural motif with heterometallic Mn(III) -Ln-Mn(III) -Ln (Ln=Dy, Er, Yb, Tb, Y) alternate arrangement and single-molecule magnet behavior.

    PubMed

    Yang, Hua; Cao, Fan; Li, Dacheng; Zeng, Suyuan; Song, You; Dou, Jianmin

    2015-10-01

    Mixed 3d-4f 12-azametallacrown-4 complexes, [Mn2 Ln2 (OH)2 (hppt)4 (OAc)2 (DMF)2 ]⋅2 DMF⋅H2 O [Ln=Dy (1), Er (2), Yb (3), Tb (4) and Y (5), H2 hppt=3-(2-hydroxyphenyl)-5-(pyrazin-2-yl)-1,2,4-triazole)], were synthesized by reactions of H2 hppt with Mn(OAc)2 ⋅4 H2 O and Ln(NO3 )3 ⋅6 H2 O. This is the first 3d-4f azametallacrown family to incorporate Ln ions into the ring sets. These isostructural complexes exhibit alternating arrangements of two Mn and two Ln ions in the rings with each pair of metal centers bound by an NN group and μ2 -O bridging. Magnetic measurements revealed dominant antiferromagnetic interactions between metal centers, and frequency-dependent out-of-phase (${\\chi {^\\prime}{^\\prime}_{\\rm{M}} }$) signals below 4 K suggest slow relaxation of magnetization. PMID:26295925

  3. Simple correction for the sample shape and radial offset effects on SQUID magnetometers: Magnetic measurements on Ln{sub 2}O{sub 3} (Ln=Gd, Dy, Er) standards

    SciTech Connect

    Morrison, Gregory; Loye, Hans-Conrad zur

    2015-01-15

    An increased focus on magnetic measurements of oriented single crystals, thin films, and magnetically dilute systems has led to a demand for the measurement of weak magnetic moments. This level of sensitivity and precision can be achieved on SQUID magnetometers by decreasing the size of the detection coils. However, the smaller detection coils can amplify two errors in the magnitude of the measured moment, the sample shape and radial offset effects, which were small and typically unaccounted for on previous magnetometers. We report a simple method to determine the radial offset of a sample by taking advantage of the two basic scan modes, DC and lock-in, typically used on magnetometers. This technique allows for the correction of the sample shape and radial offset effects in order to obtain the true moment of a sample. To show the efficacy of this technique, we report the magnetic properties of Ln{sub 2}O{sub 3} (Ln=Gd, Dy, Er). - Graphical abstract: Correction for the sample shape and radial offset effects on SQUID magnetometers using a combination of DC and VSM scan data. - Highlights: • Sample shape and radial offset effects alter the moment measured by magnetometers. • We present a simple method to correct for these sample effects on magnetometers. • We measure magnetic susceptibilities of Ln{sub 2}O{sub 3} to show the efficacy of this method.

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

    PubMed

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

    2012-07-28

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

  5. Structure determination of KScS₂, RbScS₂ and KLnS₂ (Ln = Nd, Sm, Tb, Dy, Ho, Er, Tm and Yb) and crystal-chemical discussion.

    PubMed

    Havlák, Lubomír; Fábry, Jan; Henriques, Margarida; Dušek, Michal

    2015-07-01

    The title structures of KScS2 (potassium scandium sulfide), RbScS2 (rubidium scandium sulfide) and KLnS2 [Ln = Nd (potassium neodymium sufide), Sm (potassium samarium sulfide), Tb (potassium terbium sulfide), Dy (potassium dysprosium sulfide), Ho (potassium holmium sulfide), Er (potassium erbium sulfide), Tm (potassium thulium sulfide) and Yb (potassium ytterbium sulfide)] are either newly determined (KScS2, RbScS2 and KTbS2) or redetermined. All of them belong to the α-NaFeO2 structure type in agreement with the ratio of the ionic radii r(3+)/r(+). KScS2, the member of this structural family with the smallest trivalent cation, is an extreme representative of these structures with rare earth trivalent cations. The title structures are compared with isostructural alkali rare earth sulfides in plots showing the dependence of several relevant parameters on the trivalent cation crystal radius; the parameters thus compared are c, a and c/a, the thicknesses of the S-S layers which contain the respective constituent cations, the sulfur fractional coordinates z(S(2-)) and the bond-valence sums. PMID:26146403

  6. Study of 2003 YT1 Asteroid

    NASA Astrophysics Data System (ADS)

    Vodniza, A. Q.; Rojas, M.

    2011-10-01

    The asteroid 2003 YT1 was at approximately 25 million kilometers from the Earth on May 05-2011 (U.T) [1]. It has an orbital period of 1.17 years and it was estimated to have a size of 2.63 kilometers [2]. From our Observatory, located in Pasto-Colombia, we captured several pictures, videos and astrometry data during three days. Our data was published by the Minor Planet Center (MPC) and also appears at the web page of NEODyS [3]. Our observatory's code at the MPC is "H78". Pictures of the asteroid were captured with the following equipment: 14" LX200 GPS MEADE (f/10 Schmidt-Cassegrain Telescope) and STL-1001 SBIG camera. This asteroid has a rotation period of 2.343 hours [4] and its binary nature was noted by the Modra and Ondrejov Observatories independently [5]. Nolan used radar observations to determine that this is a binary with sizes of approximately 1 and 0.2 km and primary rotation period of P < 2.6 h [6]. The asteroid will be at approximately 0.0348 A.U from the Earth on October 31-2016 and at approximately 0.0113 A.U from the Earth on October 31-2016 [7]. Astrometry was carried out, and we calculated the orbital elements. It was designed a computing program on Visual Basic 6.0. SPACEWEATHER published our video of 2003YT1 on May 5/2011 [8].

  7. Synthesis and characterization of monodisperse spherical SiO{sub 2}-RE{sub 2}O{sub 3} (RE=rare earth elements) and SiO{sub 2}-Gd{sub 2}O{sub 3}:Ln{sup 3+} (Ln=Eu, Tb, Dy, Sm, Er, Ho) particles with core-shell structure

    SciTech Connect

    Wang, H.; Yang, J.; Zhang, C.M.; Lin, J.

    2009-10-15

    Spherical SiO{sub 2} particles have been coated with rare earth oxide layers by a Pechini sol-gel process, leading to the formation of core-shell structured SiO{sub 2}-RE{sub 2}O{sub 3} (RE=rare earth elements) and SiO{sub 2}-Gd{sub 2}O{sub 3}:Ln{sup 3+} (Ln=Eu, Tb, Dy, Sm, Er, Ho) particles. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence (PL), and cathodoluminescence spectra as well as lifetimes were used to characterize the resulting SiO{sub 2}-RE{sub 2}O{sub 3} (RE=rare earth elements) and SiO{sub 2}-Gd{sub 2}O{sub 3}:Ln{sup 3+} (Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}, Sm{sup 3+}, Er{sup 3+}, Ho{sup 3+}) samples. The obtained core-shell phosphors have perfect spherical shape with narrow size distribution (average size ca. 380 nm), smooth surface and non-agglomeration. The thickness of shells could be easily controlled by changing the number of deposition cycles (40 nm for two deposition cycles). Under the excitation of ultraviolet, the Ln{sup 3+} ion mainly shows its characteristic emissions in the core-shell particles from Gd{sub 2}O{sub 3}:Ln{sup 3+} (Eu{sup 3+}, Tb{sup 3+}, Sm{sup 3+}, Dy{sup 3+}, Er{sup 3+}, Ho{sup 3+}) shells. - Graphical abstract: The advantages of core-shell phosphors are the easy availability of homogeneous spherical morphology in different size, and its corresponding luminescence color can change from red, yellow to green.

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

    PubMed

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

    2014-02-01

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

  9. Controlled synthesis and luminescence properties of Ca0.5Y1-x(MoO4)2:xRE3+ (RE = Eu, Pr, Sm, Tb, Dy, Yb/Er, Yb/Tm, and Yb/Ho) phosphors by hydrothermal method versus pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Mahalingam, Venkatakrishnan; Thirumalai, Jagannathan; Krishnan, Rajagopalan; Chandramohan, Rathinam

    2016-01-01

    Herein, we report on rare-earth (RE) activated Ca0.5Y1-x(MoO4)2:xRE3+ (RE = Eu, Pr, Sm, Tb, Dy, Yb/Er, Yb/Ho, and Yb/Tm) phosphors synthesized using a surfactant-mediated hydrothermal route. Timedependent experiments were performed, and the morphological evolution of the phosphors was studied. From prepared powder samples of Ca0.5Y1-x(MoO4)2:xRE3+ (RE = Eu and Yb/Er), nano-sized thin phosphor films were grown using pulsed laser deposition (PLD). The surface topography of the as-grown thin phosphor films was analyzed. The asprepared phosphors were characterized by structural and optical studies. The powder phosphor exhibited bi pyramid-like micro-architectures. Structural studies indicated that Ca0.5Y1-x(MoO4)2 possesses the scheelite tetragonal crystal structure. The down-conversion luminescence of Ca0.5Y1-x(MoO4)2:xRE3+ (RE = Eu, Pr, Sm, Tb, and Dy) as powder phosphors and Eu3+ doped Ca0.5Y1-x(MoO4)2 thin phosphor film were studied. Upon irradiation with a 980 nm laser, the Ca0.5Y1-x(MoO4)2: xRE3+ (RE = Yb/Er, Yb/Ho, and Yb/Tm) powder phosphors and Ca0.5Y1-x(MoO4)2:xRE3+ (RE = Yb/Er) thin phosphor film showed intense up-converted visible emissions in green, yellow, and blue regions. The fluorescence decay time and color co-ordinates were determined for all synthesized phosphors. From the obtained results, the prepared powder and thin film phosphors are suggested to be suitable candidates for display and electro-luminescence applications. [Figure not available: see fulltext.

  10. The phase diagram and tetragonal superstructures of the rare earth cobaltate phases Ln1- xSr xCoO 3- δ ( Ln=La 3+, Pr 3+, Nd 3+, Sm 3+, Gd 3+, Y 3+, Ho 3+, Dy 3+, Er 3+, Tm 3+ and Yb 3+)

    NASA Astrophysics Data System (ADS)

    James, M.; Cassidy, D.; Goossens, D. J.; Withers, R. L.

    2004-06-01

    Single phase perovskite-based rare earth cobaltates ( Ln1- xSr xCoO 3- δ) ( Ln=La 3+, Pr 3+, Nd 3+, Sm 3+, Gd 3+, Dy 3+, Y 3+, Ho 3+, Er 3+, Tm 3+ and Yb 3+; 0.67⩽ x⩽0.9) have been synthesized at 1100°C under 1 atmosphere of oxygen. X-ray diffraction of phases containing the larger rare earth ions La 3+, Pr 3+ and Nd 3+ reveals simple cubic structures; however electron diffraction shows orientational twinning of a local, tetragonal ( I4/ mmm; ap× ap×2 ap) superstructure phase. Orientational twinning is also present for Ln1- xSr xCoO 3- δ compounds containing rare earth ions smaller than Nd 3+. These compounds show a modulated intermediate parent with a tetragonal superstructure ( I4/ mmm; 2 ap×2 ap×4 ap). Thermogravimetric measurements have determined the overall oxygen content, and these phases show mixed valence (3 +/4 +) cobalt oxidation states with up to 50% Co(IV). X-ray diffraction data and Rietveld techniques have been used to refine the structures of each of these tetragonal superstructure phases ( Ln=Sm 3+-Yb 3+). Coupled Ln/Sr and oxygen/vacancy ordering and associated structural relaxation are shown to be responsible for the observed superstructure.

  11. Magnetic ordering in the pyrochlore Ho{sub 2}CrSbO{sub 7} determined from neutron diffraction, and the magnetic properties of other RE{sub 2}CrSbO{sub 7} phases (RE=Y, Tb, Dy, Er)

    SciTech Connect

    Whitaker, Mariana J.; Greaves, Colin

    2014-07-01

    The magnetic structure of the pyrochlore Ho{sub 2}CrSbO{sub 7}, which orders magnetically below 13 K, has been studied using neutron powder diffraction. Ho{sub 2}CrSbO{sub 7} is found to form an “ordered spin-ice structure” where the magnetic moments are constrained along the 111 axes, but with a ferromagnetic moment in one direction. The Cr{sup 3+} ions order ferromagnetically and this is thought to lift the degeneracy of the x, y and z directions in the cubic structure causing the ferromagnetic component from the Ho{sup 3+} ions to align. The pyrochlores RE{sub 2}CrSbO{sub 7} where RE=Y, Tb, Dy and Er have also been prepared and studied using SQUID magnetometry. - Graphical abstract: The Ho magnetic moments align to provide an overall ferromagnetic moment along [001]. - Highlights: • Despite having inherent frustration on the Ho sublattice, Ho{sub 2}CrSbO{sub 7} orders ferromagnetically below 13 K. • Ordering on the Cr/Sb sublattice appears to remove the degenerate ground state for the Ho order. • The Ho{sup 3+} magnetic moments are aligned along <111> directions by crystal field effects. • Y{sub 2}CrSbO{sub 7} with diamagnetic Y{sup 3+} ions also has a ferromagnetic ground state.

  12. 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)

    NASA Astrophysics Data System (ADS)

    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.

  13. Microscopic mechanistic study on the multiferroic of R2CoMnO6/La2CoMnO6 (R = Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm) by chemical and hydrostatic pressures: a first-principles calculation.

    PubMed

    Meng, Junling; Liu, Xiaojuan; Hao, Xianfeng; Zhang, Lifang; Yao, Fen; Meng, Jian; Zhang, Hongjie

    2016-09-14

    A specific class of multiferroic superlattices R2CoMnO6/La2CoMnO6 (R = Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm), which displayed observable electric polarizations and considerable magnetization, were investigated based on density functional theory. The multiferroic behavior was induced by both of the a(-)a(-)c(+) Glazer rotation patterns of BO6 (CoO6 and MnO6) octahedra and ferromagnetic coupling in the magnetic ordered superlattices. In addition, the ferroelectric and ferromagnetic properties of R2CoMnO6/La2CoMnO6 superlattices can be tuned by chemical pressure and hydrostatic pressure, with the former being more effective in tuning magnetoelectric properties than the latter. For chemical pressure, the incorporation of lanthanide ions promoted an increase of BO6 octahedral tilting, reflected by the sharp decrease of Co-O3-Mn bond angles in the R-layer along the c axis. By contrast, the hydrostatic pressure acts on all three directions of the superlattice so that the change in Co-O-Mn bond angles is relatively small, therefore the octahedral distortion is much smaller than that caused by chemical pressure. Consequently, the electric polarization and magnetization changed more slowly. Our first-principles simulations proposed a series of rational multiferroic superlattices with tunable ferromagnetism and ferroelectricity by chemical and hydrostatic pressures, with expectation to be applied as novel spintronic materials. PMID:27506617

  14. Synthesis, structure and properties of the oxychalcogenide series A{sub 4}O{sub 4}TiSe{sub 4} (A=Sm, Gd, Tb, Dy, Ho, Er and Y)

    SciTech Connect

    Tuxworth, A.J.; Evans, J.S.O.

    2014-02-15

    Seven oxyselenide materials have been synthesised with composition A{sub 4}O{sub 4}TiSe{sub 4} (A=Sm, Gd–Er, Y) via solid state reactions of A{sub 2}O{sub 3}, TiSe{sub 2} and Se at 900 °C. They are all isostructural with Gd{sub 4}O{sub 4}TiSe{sub 4}. Structures have been refined from powder X-ray diffraction data and have monoclinic C2/m symmetry with unit cell parameters of a≈15.7 Å, b≈3.75 Å, c≈9.65 Å and β≈117.5°. They contain infinite ribbons of edge-sharing A{sub 4}O and A{sub 3}TiO tetrahedra 4 units wide, which are linked by chains of TiSe{sub 4}O{sub 2} edge-sharing octahedra. Compositions A=Gd–Ho, Y are semiconductors with conductivities 1–3 Sm{sup −1} at 300 K, with electronic band gaps of between 0.25 and 0.37 eV. Magnetic susceptibility is reported from 1.8 K to 300 K for compositions A=Gd–Ho. Rare earth moments appear to order antiferromagnetically at low temperatures with Gd and Tb showing evidence of ferromagnetism due to spin canting over a narrow temperature range close to T{sub N}. - Graphical abstract: Illustration of the A{sub 4}O{sub 4}TiSe{sub 4} crystal structure (C2/m symmetry), A{sub 4}O and A{sub 3}TiO edge sharing tetrahedral ribbons in red, chains of edge-sharing TiSe{sub 4}O{sub 2} in blue. Rare earth=green, titanium=blue, selenium=yellow, and oxygen=red. Display Omitted - Highlights: • Seven materials with A{sub 4}O{sub 4}TiSe{sub 4} (A=Sm, Gd–Er, Y) have been synthesised as bulk phases for the first time. • Materials are semiconductors and order antiferromagnetically at ∼4 K. • Structure contains M{sub 4}O tetrahedral ribbons and TiSe{sub 4}O{sub 2} 1D octahedral chains.

  15. Synthesis and morphology of Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals with tungsten bronze structure in RE{sub 2}O{sub 3}-BaO-Nb{sub 2}O{sub 5}-B{sub 2}O{sub 3} glasses (RE: Sm, Eu, Gd, Dy, Er)

    SciTech Connect

    Ida, H.; Shinozaki, K.; Honma, T.; Oh-ishi, K.; Komatsu, T.

    2012-12-15

    Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals with a tetragonal tungsten bronze (TTB) structure are synthesized using a conventional glass crystallization technique in 2.3RE{sub 2}O{sub 3}-27.4BaO-34.3Nb{sub 2}O{sub 5}-36B{sub 2}O{sub 3} (mol%) (RE=Sm, Eu, Gd, Dy, and Er) glasses. One sharp crystallization peak is observed at {approx}670 Degree-Sign C in both powdered and bulk glasses, and the formation of Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals with unit cell parameters of a{approx}1.24 nm and c{approx}0.39 nm was confirmed. It is found from high resolution transmission electron microscope observations that the morphology of Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals is ellipsoidal. Their average particle size is in the range of 15-60 nm and decreases with decreasing ionic radius of RE{sup 3+} being present in the precursor glasses. The optical transparent crystallized glass (bulk) shows the total photoluminescence (PL) quantum yield of 53% in the visible region of Eu{sup 3+} ions, suggesting a high potential of Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals as PL materials. - Graphical abstract: This figure shows a TEM photograph for the heat-treated (667 Degree-Sign C, 3 h) sample of 2.3Dy{sub 2}O{sub 3}-27.4BaO-34.3Nb{sub 2}O{sub 5}-36B{sub 2}O{sub 3}. An ellipsoidal-shaped Ba{sub 1-x}Dy{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystal with diameters of 17 and 28 nm is observed. The ellipsoidal morphology is a common feature in Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals synthesized by the crystallization of 2.3RE{sub 2}O{sub 3}-27.4BaO-34.3Nb{sub 2}O{sub 5}-36B{sub 2}O{sub 3} glasses. Highlights: Black-Right-Pointing-Pointer Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals with a tetragonal tungsten bronze structure are synthesized. Black-Right-Pointing-Pointer A glass crystallization technique was applied. Black-Right-Pointing-Pointer The morphology of Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals is

  16. 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).

    PubMed

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

    2016-12-01

    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 RE(3+), 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. PMID:27405467

  17. Methane as a Selectivity Booster in the Arc-Discharge Synthesis of Endohedral Fullerenes: Selective Synthesis of the Single-Molecule Magnet Dy2TiC@C80 and Its Congener Dy2TiC2@C80

    PubMed Central

    Junghans, Katrins; Schlesier, Christin; Kostanyan, Aram; Samoylova, Nataliya A.; Deng, Qingming; Rosenkranz, Marco; Schiemenz, Sandra; Westerström, Rasmus; Greber, Thomas; Büchner, Bernd; Popov, Alexey A.

    2016-01-01

    The use of methane as a reactive gas dramatically increases the selectivity of the arc-discharge synthesis of M-Ti-carbide clusterfullerenes (M=Y, Nd, Gd, Dy, Er, Lu). Optimization of the process parameters allows the synthesis of Dy2TiC@C80-I and its facile isolation in a single chromatographic step. A new type of cluster with an endohedral acetylide unit, M2TiC2@C80, is discovered along with the second isomer of M2TiC@C80. Dy2TiC@C80-(I,II) and Dy2TiC2@CS0-I are shown to be single-molecule magnets (SMM), but the presence of the second carbon atom in the cluster Dy2TiC2@C80 leads to substantially poorer SMM properties. PMID:26350440

  18. YT: A Multi-Code Analysis Toolkit for Astrophysical Simulation Data

    SciTech Connect

    Turk, Matthew J.; Smith, Britton D.; Oishi, Jeffrey S.; Skory, Stephen; Skillman, Samuel W.; Abel, Tom; Norman, Michael L.; /aff San Diego, CASS

    2011-06-23

    The analysis of complex multiphysics astrophysical simulations presents a unique and rapidly growing set of challenges: reproducibility, parallelization, and vast increases in data size and complexity chief among them. In order to meet these challenges, and in order to open up new avenues for collaboration between users of multiple simulation platforms, we present yt (available at http://yt.enzotools.org/) an open source, community-developed astrophysical analysis and visualization toolkit. Analysis and visualization with yt are oriented around physically relevant quantities rather than quantities native to astrophysical simulation codes. While originally designed for handling Enzo's structure adaptive mesh refinement data, yt has been extended to work with several different simulation methods and simulation codes including Orion, RAMSES, and FLASH. We report on its methods for reading, handling, and visualizing data, including projections, multivariate volume rendering, multi-dimensional histograms, halo finding, light cone generation, and topologically connected isocontour identification. Furthermore, we discuss the underlying algorithms yt uses for processing and visualizing data, and its mechanisms for parallelization of analysis tasks.

  19. Mutation at codon 322 in the human acetylcholinesterase (ACHE) gene accounts for YT blood group polymorphism

    SciTech Connect

    Bartels, C.F.; Lockridge, O. ); Zelinski, T. )

    1993-05-01

    Acetylcholinesterase is present in innervated tissues, where its function is to terminate nerve impulse transmission. It is also found in the red blood cell membrane, where its function is unknown. The authors report the first genetic variant of human acetylcholinesterase and support the identity of acetylcholinesterase as the YT blood group antigen. DNA sequencing shows that the wild-type sequence of acetylcholinesterase with His322 (CAC) is the YT1 blood group antigen and that the rare variant of acetylcholinesterase with Asn322 (AAC) is the YT2 blood group antigen. Two additional point mutations in the acetylcholinesterase gene do not affect the amino acid sequence of the mature enzyme. 41 refs., 6 figs., 1 tab.

  20. Activation cross sections of proton and deuteron induced nuclear reactions on holmium and erbium, related to the production of (161)Er and (160)Er medical isotopes.

    PubMed

    Tárkányi, F; Ditrói, F; Takács, S; Hermanne, A; Baba, M

    2016-09-01

    Experimental excitation functions for long-lived products in proton induced reactions were measured with the activation method in the 37-65MeV energy range on natural holmium. Stacked foil irradiation technique and high resolution gamma spectrometry were used in order to measure cross-section data for the production of (161)Er, (160)Er and (1)(59,157)Dy. For comparison of the production routes of medically related (161)Er and (160)Er radioisotopes new experimental cross section data were deduced for the (162)Er(p,x)(161,160)Er and (162)Er(d,x)(161,160)Er reactions by re-evaluating gamma-ray spectra from earlier measurements. No earlier data were found in the literature for these reactions. The experimental data are compared with results of TALYS theoretical code reported in TENDL-2015. PMID:27451109

  1. Clinical significance of anti-Yt(b). Report of a case using a 51-chromium red cell survival study

    SciTech Connect

    Levy, G.J.; Selset, G.; McQuiston, D.; Nance, S.J.; Garratty, G.; Smith, L.E.; Goldfinger, D.

    1988-05-01

    Several published reports have documented the variable survival of Yt(a+) red cells (RBC) in patients with anti-Yt(a) as measured by 51-Chromium (Cr)-labeled RBC survival studies. Similar studies with anti-Yt(b) have not been reported. A /sup 51/Cr-labeled RBC survival study was performed using Yt(b+) RBCs and a monocyte monolayer assay in a young hemodialysis patient who required chronic transfusion therapy and who had developed anti-Yt(b). The survival of the transfused RBCs was 100 and 93 percent at 1 and 24 hours, respectively, with a half life of 21 days at termination of the study (normal, 28 to 32 days). These results showed no evidence of rapid destruction of the Yt(b+) RBCs, indicating that this patient could be transfused safely with blood from Yt(b+) donors. Long-term survival of the /sup 51/Cr-labeled Yt(b+) RBCs was shortened moderately, however, a finding that correlated with a slightly abnormal monocyte monolayer assay test.

  2. Chiral mononuclear lanthanide complexes and the field-induced single-ion magnet behaviour of a Dy analogue.

    PubMed

    Lin, Shuang-Yan; Wang, Chao; Zhao, Lang; Wu, Jianfeng; Tang, Jinkui

    2015-01-01

    Three pairs of homochiral mononuclear lanthanide complexes, with the general formula [LnH4LRRRRRR/SSSSSS(SCN)2](SCN)2·xCH3OH·yH2O(Ln = Dy (R/S-Dy1), Ho (R/S-Ho1) and Er (R/S-Er1)), have been obtained via self-assembly between chiral macrocyclic ligands and the respective thiocyanates, all of which show a saddle-type conformation with seven-coordinated metal ions. Magnetic measurements revealed that the Dy complex shows field-induced single-ion magnet behaviour, which is rarely reported in a seven-coordinated lanthanide-based SIM encapsulated in a macrocyclic ligand. The absolute configuration of all enantiomers was determined by single crystal X-ray crystallography and confirmed by electronic CD and VCD spectra. PMID:25369972

  3. Enhanced Ferroelectric Polarization by Induced Dy Spin Order in Multiferroic DyMnO{sub 3}

    SciTech Connect

    Prokhnenko, O.; Landsgesell, S.; Aliouane, N.; Argyriou, D. N.; Feyerherm, R.; Dudzik, E.

    2007-02-02

    Neutron powder diffraction and single crystal x-ray resonant magnetic scattering measurements suggest that Dy plays an active role in enhancing the ferroelectric polarization in multiferroic DyMnO{sub 3} above T{sub N}{sup Dy}=6.5 K. We observe the evolution of an incommensurate ordering of Dy moments with the same periodicity as the Mn spiral ordering. It closely tracks the evolution of the ferroelectric polarization. Below T{sub N}{sup Dy}, where Dy spins order commensurately, the polarization decreases to values similar for those of TbMnO{sub 3}. The higher P{sub s} found just above T{sub N}{sup Dy} arises from the contribution of Dy spins so as to effectively increase the amplitude of the Mn spin spiral.

  4. Lifetime Measurements in 162Dy

    NASA Astrophysics Data System (ADS)

    Casarella, Clark; Aprahamian, A.; Lesher, S.; Crider, B.; Lowe, M.; Peters, E.; Prados-Estevez, F.; Ross, T.; Tully, Z.; Yates, S.

    2015-10-01

    Historically, the rare-earth region of nuclei has been a fountainhead for nuclear structure phenomena. One of the more debated structure effects is the nature of excited 0+ bands in nuclei, and continues to be an outstanding challenge in nuclear structure physics; several interpretations exist, and we hope that lifetime measurements can help distinguish between them. 162Dy has an abundance of 0+ states with limited lifetime data; we have measured excitation functions, mean lifetimes, and angular distributions of gamma rays for excited states in 162Dy at the University of Kentucky Accelerator Laboratory. Low lying excited states were populated up to an excitation energy of E < 3.2 MeV, where we will discuss the implications of the lifetimes under this energy threshold. This work was supported by the NSF under contract numbers PHY-1068192, PHY-1205412, and PHY-0956310.

  5. A planar triangular Dy3 + Dy3 single-molecule magnet with a toroidal magnetic moment.

    PubMed

    Li, Xiao-Lei; Wu, Jianfeng; Tang, Jinkui; Le Guennic, Boris; Shi, Wei; Cheng, Peng

    2016-07-21

    A unique Dy6 complex with a planar Dy3 + Dy3 structure was assembled by delicately modifying the axial ligands. Single-molecule magnet behavior and meanwhile a toroidal magnetic moment in the ground state have been observed. PMID:27388113

  6. Magnetic structure of DyFe3

    NASA Astrophysics Data System (ADS)

    Jin, Long-huan; W, J. James; J, Rhyne; R, Lemaire

    1985-06-01

    Powder neutron diffraction measurements have been carried out on the intermetallic compound DyFe3 at 4 and 295K. The magnetic structure of the compound at 4 and 295K are noncollinear but coplanar in the a-c plane, and the moments of the Dy and Fe ions lie closer to the basal plane.

  7. [166Dy]Dy/166Ho hydroxide macroaggregates: an in vivo generator system for radiation synovectomy.

    PubMed

    Ferro-Flores, G; Hernández-Oviedo, O; Arteaga de Murphy, C; Tendilla, J I; Monroy-Guzmán, F; Pedraza-López, M; Aldama-Alvarado, K

    2004-12-01

    Radiation synovectomy is an effective treatment in patients suffering from inflammatory-rheumatoid and degenerative joint diseases. The aim of this work was to examine the feasibility of preparing dysprosium-166 (166Dy)/holmium-166(166Ho) hydroxide macroaggregates ([166Dy]Dy/166Ho-HM) as an in vivo generator for radiation synovectomy evaluating whether the stability of 166Dy-HM and 166Ho-HM complexes is maintained when the daughter 166Ho is formed. The Monte Carlo (MCNP4B) theoretical depth dose profile for the in vivo [166Dy]Dy/166Ho generator system in a joint model was calculated and compared with that produced by 90Y, 153Sm and 166Ho. 166Dy was obtained by neutron irradiation of enriched 164Dy2O3 in a Triga Mark III reactor. Macroaggregates were prepared by reaction of [166Dy]DyCl3 with 0.5 M NaOH in an ultrasonic bath. [166Dy]Dy/166Ho-HM was obtained with radiochemical purity >99.5% and with the majority of particles in the 2-5 microm range. In vitro studies demonstrated that the radio-macroaggregates are stable in saline solution and human serum without a significant change in the particle size over 14 d, suggesting that no translocation of the daughter nucleus occurs subsequent to beta- decay of 166Dy. Biological studies in normal rats demonstrated high retention in the knee joint even 7 d after [166Dy]Dy/166Ho-HM administration. The Monte Carlo (MCNP4B) theoretical depth dose profiles in a joint model, showed that the in vivo [166Dy]Dy/166Ho generator system would produce 25% and 50% less radiation dose to the articular cartilage and bone surface, respectively, than that produced by 90Y or pure 166Ho in a treatment with the same therapeutic dose to the synovium surface. Despite that 153Sm showed the best depth dose profile sparing doses to healthy tissues, the use of 166Dy could provide the advantage of being applied in patients that cannot be reached within a few hours from a nuclear reactor and to produce less radiation exposure to the medical personnel

  8. Magnetocaloric properties of rare-earth substituted DyCrO3

    NASA Astrophysics Data System (ADS)

    McDannald, A.; Jain, M.

    2015-07-01

    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 (RCrO3), especially DyCrO3, with its large magnetic moment dysprosium ion, are potential candidates for such an application. The Dy3+ 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 Y3+ and Ho3+ substitutions were found to decrease the magnetocaloric response by disrupting the R3+ ordering. Whereas Er3+ substitution was found to increase the magnetocaloric response, likely due to an increase in the R3+ ordering temperature. The large magnetocaloric entropy change of Er3+ substituted DyCrO3 (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.

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

    SciTech Connect

    McDannald, A.; Jain, M.

    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.

  10. 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.

    PubMed

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

    2010-09-01

    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. PMID:20704320

  11. Amelioration of ischemia/reperfusion-induced myocardial infarction by the 2-alkynyladenosine derivative 2-octynyladenosine (YT-146).

    PubMed

    Sasamori, Jun; Aihara, Kazuyuki; Yoneyama, Fumiya; Sato, Isamu; Kogi, Kentaro; Takeo, Satoshi

    2006-04-01

    The present study was aimed at determining whether the novel adenosine A2-agonist YT-146 may have cardioprotective effects against ischemia-reperfusion injury. Anesthetized open-chest dogs underwent 90-min occlusion of the left anterior descending artery and subsequent 300-min reperfusion. The animals were randomly assigned to receive vehicle, 3, or 10 microg/kg YT-146 or ischemic preconditioning (4 episodes of 5 min occlusion followed by 5 min of reperfusion). Blood pressure, heart rate, and regional myocardial blood flow throughout the experiment were measured, as was the myocardial infarct size after reperfusion. The infarct size of the vehicle-treated dog was 56.2% +/- 2.7% (n = 5), whereas that of 3 or 10 microg/kg YT-146-treated dog was smaller (ie, 29.5% +/- 8.7% or 20.2% +/- 7.0%, respectively; n = 5). The infarct size of the dog treated with 10 microg/kg YT-146 was reduced to a degree similar to that of the ischemic preconditioning (19.2% +/- 6.3%, n = 5). YT-146 at both doses elicited a dose-dependent increase in acute hyperemic coronary flow immediately after reperfusion. The cardioprotective effect may be attributed to the limitation of the infarct size, probably via A2-receptor-mediated coronary artery dilatation during the early period of reperfusion. PMID:16680077

  12. Dy:PbGa2S4 laser radiation and its delivery by hollow waveguide

    NASA Astrophysics Data System (ADS)

    Jelínková, Helena; Nemec, Michal; Miyagi, Mitsunobu; Iwai, Katsumasa; Takaku, Hiroyuki; Doroshenko, Maxim; Basiev, Tasoltan T.; Badikov, Valerii V.; Badikov, Dmitri V.

    2012-01-01

    The mid-infrared radiation generated by bulk Dy:PbGa2S4 laser working at room temperature was characterized and for its delivery the special type of COP/Ag hollow waveguide was used. The optical pumping of Dy:PbGa2S4 laser was performed by flashlamp pumped Er:YLF laser at 1.73 μm wavelength. The compact 60 mm long Dy:PbGa2S4 laser oscillator worked in free-running mode with the repetition rate 1.5 Hz. The output energy was 5.1 mJ in 80 μs long pulse at 4.3 μm wavelength. The spatial beam structure was close to the Gaussian shape. The goal of the presented study was the preliminary investigation of the mid-infrared Dy:PbGa2S4 radiation delivery possibility by the cyclic olefin polymer and silver coated hollow glass waveguide. The length of the waveguide was 103 cm and the inner diameter was 700 μm. The thickness of the polymer inner layer was calculated for the optimal 4 μm radiation transmission. Mid-infrared laser radiation was coupled into the waveguide by the CaF2 lens with the focal length 55 mm. The characterization of delivered 4.3 μm radiation was provided. It was observed that the spatial structure is changing essentially, which follows from the transmission principle of the hollow waveguide. As conclude the delivery system for 4.3 μm mid-infrared Dy:PbGa2S4 laser radiation was investigated for the first time.

  13. Decay of the neutron-rich isotope 171Ho and the identification of 169Dy

    NASA Astrophysics Data System (ADS)

    Chasteler, R. M.; Nitschke, J. M.; Firestone, R. B.; Vierinen, K. S.; Wilmarth, P. A.

    1990-10-01

    Neutron-rich rare-earth isotopes were produced in multinucleon transfer reactions between 170Er ions and natW targets. On-line mass separation was used together with β- and γ-ray spectroscopy in these studies. At mass A=169, the heaviest known dysprosium isotope, 39(8) s,169Dy, was identified. It was observed to β- decay to the ground state of 169Ho or through a level at 1578 keV. In the A=171 mass chain, a partial decay scheme for 55(3)-s 171Ho was determined.

  14. Manipulation of Dy-Mn coupling and ferrielectric phase diagram of DyMn2O5: The effect of Y substitution of Dy

    NASA Astrophysics Data System (ADS)

    Zhao, Z. Y.; Wang, Y. L.; Lin, L.; Liu, M. F.; Li, X.; Yan, Z. B.; Liu, J.-M.

    2015-11-01

    DyMn2O5 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 DyMn2O5 where the exchange-strictions associated with the Mn3+-Mn4+-Mn3+ blocks and Dy3+-Mn4+-Dy3+ blocks generate the two ferroelectric sublattices, we perform a set of characterizations on the structure, magnetism, and electric polarization of Dy1-xYxMn2O5 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 Dy3+ spin ordering and the Dy-Mn coupling. Consequently, the ferroelectric sublattice generated by the exchange striction associated with the Dy3+-Mn4+-Dy3+ blocks is destabilized, but the ferroelectric sublattice generated by the exchange striction associated with the Mn3+-Mn4+-Mn3+ 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 DyMn2O5 but probably also other RMn2O5 members with strong 4f-3d coupling.

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

    SciTech Connect

    Zhao, Z. Y.; Wang, Y. L.; Lin, L.; Liu, M. F.; Li, X.; Yan, Z. B.; Liu, J.-M.

    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.

  16. Electromagnetic transition strengths in {sup 156}Dy

    SciTech Connect

    Moeller, O.; Dewald, A.; Saha, B.; Fitzler, A.; Jessen, K.; Klug, T.; Heinze, S.; Jolie, J.; Brentano, P. von; Petkov, P.; Tonev, D.; Bazzacco, D.; Ur, C. A.; Lunardi, S.; Farnea, E.; Axiotis, M.; Angelis, G. de; Napoli, D. R.; Marginean, N.; Martinez, T.

    2006-08-15

    Reliable and precise lifetimes of excited states in {sup 156}Dy were measured by means of the recoil distance Doppler-shift technique in the coincidence mode. The experiment was performed at the Laboratori Nazionali di Legnaro with the GASP array and the Cologne coincidence plunger apparatus using the reaction {sup 124}Sn({sup 36}S,4n){sup 156}Dy at a beam energy of 155 MeV. New values of the branching ratios of transitions depopulating the levels of the first excited band have been derived. The measured transition probabilities of {sup 156}Dy in the ground-state band and the first excited band as well as the energy spectra are compared to the predictions of the recently proposed X(5) model and to an interacting boson approximation fit. The comparison reveals a different behavior of the intraband transition strengths and indicates a possible coexistence of a normal deformed ground-state band and an X(5)-like first excited band. It also reveals that in {sup 156}Dy, the {gamma} degree of freedom plays a more important role than it does in the well-established X(5) nuclei with N=90. A fit of the data using the general collective model suggests that a deeper collective potential V({beta},{gamma}) may also be a reason for the differences in the spectroscopic properties of {sup 156}Dy and those nuclei.

  17. Magnetic reversal in Dy-doped DyF e2/YF e2 superlattice films

    NASA Astrophysics Data System (ADS)

    Stenning, G. B. G.; Bowden, G. J.; de Groot, P. A. J.; van der Laan, G.; Figueroa, A. I.; Bencok, P.; Steadman, P.; Hesjedal, T.

    2015-03-01

    Reversible magnetic exchange springs can be formed in the magnetically soft YF e2 layers of epitaxial DyF e2/YF e2 multilayer films. Here we show that the insertion of just two monolayers of DyF e2 , placed directly in the middle of the YF e2 layers, brings about substantial changes. Results are presented for a Dy-doped (110)-oriented [DyFe2(60Å) /YFe2(120 Å ) /DyFe2(8 Å ) /YFe2(120 Å ) ] 15 multilayer film, measured at 100 K in fields of up to ±10 T. Using bulk magnetometry, micromagnetic modeling, and Dy-specific x-ray magnetic circular dichroism, it is shown that Dy doping substantially increases the number of spin states available to the system. Altogether 12 distinct spring states are identified which bring additional complexity to the magnetic reversal process. In particular, the exchange springs are no longer reversible, exhibiting magnetic exchange-spring collapse. Full and partial magnetic loops are presented for fields applied along the in-plane easy [001] axis and the in-plane hard [1 ¯10 ] axis. In particular, it is demonstrated that exchange-spring collapse is sharpest when the field is applied along a hard in-plane [1 ¯10 ] axis.

  18. Magnetomechanical damping in cryogenic TbDy

    NASA Technical Reports Server (NTRS)

    Dooley, J.; Good, N.; White, C.; Leland, S.; Fultz, B.

    2002-01-01

    Vibration damping in polycrystalline TbDy alloys was studied at cryogenic temperatures. The material was prepared by cold-rolling to induce crystallographic texture, and was then heat-treated to relieve internal stress. Mechanical hysteretic losses were measured at various strains, frequencies, and loading configurations at 77 K. Some textured TbDy materials demonstrated 22.6% energy dissipation in mechanical measurements at low frequency (0.01 Hz) and a mean logarithmic decrement of 0.23 at a higher frequency (25 kHz). Ultrasonic velocities of longitudinal and shear elastic waves were measured on single and polycrystalline TbDy; little variation in ultrasonic velocities was found evenfor samples with large variation in crystallographic texture and magnetomechanical properties.

  19. Electromagnetic transition strengths in 155Dy

    NASA Astrophysics Data System (ADS)

    Yavahchova, M. S.; Petkov, P.; Dewald, A.; Möller, O.; Saha, B.; Fitzler, A.; Jessen, K.; Tonev, D.; Gutev, N.; Klug, T.; Heinze, S.; Jolie, J.; von Brentano, P.; Bazzacco, D.; Ur, C.; Farnea, E.; Axiotis, M.; Lunardi, S.; Rossi-Alvarez, C.; de Angelis, G.; Napoli, D. R.; Marginean, N.; Martinez, T.; Caprio, M.

    2012-05-01

    Lifetimes of excited states in 155Dy were measured by means of the Recoil Distance Doppler-shift technique in the coincidence mode. The experiment was performed at the Laboratori Nazionali di Legnaro with the GASP array and the Cologne plunger using the reaction 124Sn(36S,5n)155Dy at a beam energy of 155 MeV. The Differential decay-curve method was applied for the lifetime determination. The measured transition probabilities in 155Dy and the energy spectrum are compared to the predictions of the Particle plus rotor model. The comparison indicates slightly different quadrupole deformations characterizing the low-lying one-quasineutron bands which may point to a shape coexistence.

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

    NASA Astrophysics Data System (ADS)

    Davaasuren, Bambar; Dashjav, Enkhtsetseg; Kreiner, Guido; Borrmann, Horst; Weber, Sven-Ulf; Becker, Klaus-Dieter; Jochen Litterst, Fred; Kniep, Rüdiger

    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.

  1. Spectroscopy of neutron-rich {sup 168,170}Dy: Yrast band evolution close to the N{sub p}N{sub n} valence maximum

    SciTech Connect

    Soederstroem, P.-A.; Nyberg, J.; Regan, P. H.; Ashley, S. F.; Catford, W. N.; Gelletly, W.; Jones, G. A.; Liu, Z.; Pietri, S.; Podolyak, Zs.; Steer, S. J.; Thompson, N. J.; Williams, S. J.; Algora, A.; Angelis, G. de; Corradi, L.; Fioretto, E.; Gottardo, A.; Grodner, E.; He, C. Y.

    2010-03-15

    The yrast sequence of the neutron-rich dysprosium isotope {sup 168}Dy has been studied using multinucleon transfer reactions following collisions between a 460-MeV {sup 82}Se beam and an {sup 170}Er target. The reaction products were identified using the PRISMA magnetic spectrometer and the gamma rays detected using the CLARA HPGe-detector array. The 2{sup +} and 4{sup +} members of the previously measured ground-state rotational band of {sup 168}Dy have been confirmed and the yrast band extended up to 10{sup +}. A tentative candidate for the 4{sup +}->2{sup +} transition in {sup 170}Dy was also identified. The data on these nuclei and on the lighter even-even dysprosium isotopes are interpreted in terms of total Routhian surface calculations and the evolution of collectivity in the vicinity of the proton-neutron valence product maximum is discussed.

  2. Magnetic exchange interactions of rare-earth-substituted DyCrO3 bulk powders

    NASA Astrophysics Data System (ADS)

    McDannald, A.; Kuna, L.; Seehra, M. S.; Jain, M.

    2015-06-01

    Effects of the substitution of rare-earths R =Y , Er, and Ho on the magnetic properties of Dy0.7R0.3CrO3 are reported here in order to probe the nature of magnetism and related exchange interactions in these materials. By fitting the temperature dependence of the magnetic susceptibility to a modified Curie-Weiss law, which includes a correction for the Dzyaloshinskii-Moriya (DM) interaction, the strengths of the symmetric and antisymmetric Cr3 +-Cr3 + exchange interactions were determined. It was found that the rare-earth substitutions had a slight effect on the strength of the symmetric Cr3 +-Cr3 + interaction (reflected in the slight changes in the Néel temperatures), while the antisymmetric Cr3 +-Cr3 + interaction remained unchanged. Isothermal magnetic measurements of the samples at successive temperatures revealed a plateau in the temperature dependent magnetic coercivity data, which was explained by the magnetic properties of the substituted ions. It was found that the Y substitution led to the reduction of the strength of the magnetization and a larger peak value of magnetic coercivity as compared to that in pure DyCrO3. The observed increase in magnetic coercivity with Er and Ho substitution can be attributed to an increased R3 +-Cr3 + interaction strength dominated by the DM mechanism.

  3. Commensurate Dy magnetic ordering associated with incommensurate lattice distortion in multiferroic DyMnO{sub 3}

    SciTech Connect

    Feyerherm, R.; Dudzik, E.

    2006-05-01

    Synchrotron x-ray diffraction and resonant magnetic scattering experiments on a single crystal of orthorhombic DyMnO{sub 3} have been carried out between 4 and 40 K. Below T{sub N}{sup Dy}=5 K, the Dy magnetic moments order in a commensurate structure with propagation vector 0.5 b{sup *}. Simultaneous with the Dy magnetic ordering, an incommensurate lattice modulation with propagation vector 0.905 b{sup *} evolves while the original Mn induced modulation is suppressed and shifts from 0.78 b{sup *} to 0.81 b{sup *}. This points to a strong interference of Mn and Dy induced structural distortions in DyMnO{sub 3} besides a magnetic coupling between the Mn and Dy magnetic moments.

  4. Stability of multiferroicity against Dy/Mn off-stoichiometry in DyMnO{sub 3}

    SciTech Connect

    Wang, J. X.; Liu, M. F.; Zhao, Z. Y.; Yan, Z. B.; Liu, J.-M.

    2014-05-07

    We investigate the effects of slight Dy/Mn off-stoichiometry on the multiferroic behaviors of DyMnO{sub 3} (Dy{sub 1−x}Mn{sub 1+x}O{sub 3}). It is revealed that the distorted lattice structure and ferroelectric property exhibit higher stability against the Mn deficiency than the Dy deficiency. Since the electric polarization includes the contributions from the Mn-Mn and Dy-Mn interactions, the measured polarization exhibits different dependence on the Mn deficiency from that on the Dy deficiency. The present work suggests that the Dy/Mn off-stoichiometry is detrimental to the ferroelectricity, owing to the modulated spin interactions and reshuffled spin frustration.

  5. High-spin states in the N = 84 nucleus 152Er

    NASA Astrophysics Data System (ADS)

    Bastin, G.; Peghaire, A.; Thibaud, J. P.; Andre, S.; Barneoud, D.; Foin, C.; Aguer, P.

    1980-08-01

    High-spin states in 152Er have been populated through the 144Sm( 12C, 4n) 152Er reaction. Excitation functions, angular distributions, prompt and delayed coincidences against the beam burst were measured. Three isomeric states at 2183 keV ( τ = 1.8 ns), 4519 keV ( τ = 1.2 ns) and 4915 keV ( τ = 6.6 ns) have been observed. The decay scheme is developed up to 7 MeV and is discussed and compared with that of 150Dy.

  6. Epitaxial growth and characterization of DyP/GaAs, DyAs/GaAs, and GaAs/DyP/GaAs heterostructures

    NASA Astrophysics Data System (ADS)

    Lee, P. P.; Hwu, R. J.; Sadwick, L. P.; Balasubramaniam, H.; Kumar, B. R.; Alvis, R.; Lareau, R. T.; Wood, M. C.

    1998-05-01

    There is a significant interest in the area of improving high temperature stable contacts to III-V semiconductors. Two attractive material systems that offer promise in this area are dysprosium phosphide/gallium arsenide (DyP/GaAs) and dysprosium arsenide/gallium arsenide (DyAs/GaAs). Details of epitaxial growth of DyP/GaAs and DyAs/GaAs by molecular beam epitaxy (MBE), and their characterization by x-ray diffraction, transmission electron microscopy, atomic force microscopy, Auger electron spectroscopy, Hall measurements, and high temperature current-voltage measurements is reported. DyP is lattice matched to GaAs, with a room temperature mismatch of less than 0.01% and is stable in air with no sign of oxidation, even after months of ambient exposure. Both DyP and DyAs have been grown by solid source MBE using custom designed group V thermal cracker cells and group III high temperature effusion cells. High quality DyP and DyAs epilayer were consistently obtained for growth temperatures ranging from 500 to 600°C with growth rates between 0.5 and 0.7 µm/h. DyP epilayers are n-type with electron concentrations of 3 × 1020 to 4 × 1020 cm-3, room temperature mobilities of 250 to 300 cm2/V·s, and a barrier height of 0.81 eV to GaAs. DyAs epilayers are also n-type with carrier concentrations of 1 × 1021 to 2 × 1021 cm-3, and mobilities between 25 and 40 cm2/V·s.

  7. Magnetic and microstructural modification of the Nd-Fe-B sintered magnet by mixed DyF3/DyHx powder doping

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Hoon; Lee, Seong-Rae; Kim, Hyo-Jun; Lee, Min-Woo; Jang, Tae-Suk

    2014-05-01

    We investigated the magnetic and microstructural properties of Nd-Fe-B sintered magnets doped with DyF3, DyHx, and a mixture of DyF3 and DyHx powders. In the DyHx-doped magnet, diffusion of Dy occurs predominantly via grain boundary diffusion. However, the proportion of Dy being diffused by lattice diffusion is increased in the DyF3-doped magnet due to the different influences of F- and H+ ions. The detailed mechanism of the microstructural changes in terms of the diffusional behavior of Dy induced by the DyF3 and DyHx powder doping is discussed. The formation of a Dy-segregated Nd-rich oxide phase (RE-rich, Dy-Nd-O) was suppressed only in the DyF3-doped magnet, and the (00L) alignment of Nd2Fe14B grains in the sintered magnet increased when it was doped with the DyHx powder. We obtained the optimum microstructural and magnetic properties of the Nd-Fe-B sintered magnet through doping with a mixture of DyF3 and DyHx powders, which compensated for the drawbacks of using each powder alone.

  8. Labeling of biotin with [166Dy]Dy/166Ho as a stable in vivo generator system.

    PubMed

    Ferro-Flores, G; Arteaga de Murphy, C; Pedraza-López, M; Monroy-Guzmán, F; Meléndez-Alafort, L; Tendilla, J I; Jiménez-Varela, R

    2003-04-14

    The aim of this work was to synthesize [166Dy]Dy/166Ho-DTPA-Biotin to evaluate its potential as a new radiopharmaceutical for targeted radiotherapy. Dysprosium-166 (166Dy) was obtained by neutron irradiation of enriched 164Dy(2)O(3) in a Triga Mark III reactor. The labeling was carried out in aqueous media at pH 8.0 by addition of [166Dy]DyCl(3) to diethylenetriaminepentaacetic-alpha,omega-bis(biocytinamide) (DTPA-Biotin). Radiochemical purity was determined by high-performance liquid chromatography (HPLC) and TLC. The biological integrity of labeled biotin was studied evaluating its avidity for avidin in an agarose column and by size-exclusion HPLC analysis of the radiolabeled DTPA-Biotin with and without the addition of avidin. Stability studies against dilution were carried out by diluting the radiocomplex solution with saline solution and with human serum at 37 degrees C for 24 h. The [166Dy]Dy/166Ho-labeled biotin was obtained with a 99.1+/-0.6% radiochemical purity. In vitro studies demonstrated that [166Dy]Dy/166Ho-DTPA-Biotin is stable after dilution in saline and in human serum and no translocation of the daughter nucleus occurs subsequent to beta(-) decay of 166Dy that could produce release of 166Ho(3+). Avidity of labeled biotin for avidin was not affected by the labeling procedure. Biodistribution studies in normal mice showed that the [166Dy]Dy/166Ho-DTPA-Biotin has a high renal clearance. In conclusion, the radiolabeled biotin prepared in this investigation has adequate properties to work as a stable in vivo generator system for targeted radiotherapy. PMID:12672609

  9. Thermochromism and fluorescence in dyed PEO films

    NASA Astrophysics Data System (ADS)

    Kamath, Archana; S, Raghu; V, Mini; C, Sharanappa; H, Devendrappa

    2015-06-01

    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.

  10. Thermochromism and fluorescence in dyed PEO films

    SciTech Connect

    Kamath, Archana; S, Raghu; V, Mini; C, Sharanappa; H, Devendrappa

    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.

  11. Na3DyCl6

    PubMed Central

    Schurz, Christian M.; Meyer, Gerd; Schleid, Thomas

    2011-01-01

    Single crystals of the title compound, tris­odium hexa­chloridodysprosate, Na3DyCl6, were obtained as a by-product of synthesis using dysprosium(III) chloride and sodium chloride among others. The monoclinic structure with its typical β angle close to 90° [90.823 (4)°] is isotypic with the mineral cryolite (Na3AlF6) and the high-temperature structure of the Na3 MCl6 series, with M = Eu–Lu, Y and Sc. The isolated, almost perfect [DyCl6]3− octa­hedra are inter­connected via two crystallographically different Na+ cations: while one Na+ resides on centres of symmetry (as well as Dy3+) and also builds almost perfect, isolated [NaCl6]5− octa­hedra, the other Na+ is surrounded by seven chloride anions forming a distorted [NaCl7]6− trigonal prism with just one cap as close secondary contact. PMID:21754259

  12. Na(3)DyCl(6).

    PubMed

    Schurz, Christian M; Meyer, Gerd; Schleid, Thomas

    2011-05-01

    Single crystals of the title compound, tris-odium hexa-chloridodysprosate, Na(3)DyCl(6), were obtained as a by-product of synthesis using dysprosium(III) chloride and sodium chloride among others. The monoclinic structure with its typical β angle close to 90° [90.823 (4)°] is isotypic with the mineral cryolite (Na(3)AlF(6)) and the high-temperature structure of the Na(3)MCl(6) series, with M = Eu-Lu, Y and Sc. The isolated, almost perfect [DyCl(6)](3-) octa-hedra are inter-connected via two crystallographically different Na(+) cations: while one Na(+) resides on centres of symmetry (as well as Dy(3+)) and also builds almost perfect, isolated [NaCl(6)](5-) octa-hedra, the other Na(+) is surrounded by seven chloride anions forming a distorted [NaCl(7)](6-) trigonal prism with just one cap as close secondary contact. PMID:21754259

  13. ER-2 in flight

    NASA Technical Reports Server (NTRS)

    1996-01-01

    In this film clip, we see an ER-2 on its take off roll and climb as it departs from runway 22 at Edwards AFB, California. In 1981, NASA acquired its first ER-2 aircraft. The agency obtained a second ER-2 in 1989. These airplanes replaced two Lockheed U-2 aircraft, which NASA had used to collect scientific data since 1971. The U-2, and later the ER-2, were based at the Ames Research Center, Moffett Field, California, until 1997. In 1997, the ER-2 aircraft and their operations moved to NASA Dryden Flight Research Center, Edwards, California. Since the inaugural flight for this program, August 31, 1971, NASA U-2 and ER-2 aircraft have flown more than 4,000 data missions and test flights in support of scientific research conducted by scientists from NASA, other federal agencies, states, universities, and the private sector. NASA is currently using two ER-2 Airborne Science aircraft as flying laboratories. The aircraft, based at NASA Dryden, collect information about our surroundings, including Earth resources, celestial observations, atmospheric chemistry and dynamics, and oceanic processes. The aircraft also are used for electronic sensor research and development, satellite calibration, and satellite data validation. The ER-2 is a versatile aircraft well-suited to perform multiple mission tasks. It is 30 percent larger than the U-2 with a 20 feet longer wingspan and a considerably increased payload over the older airframe. The aircraft has four large pressurized experiment compartments and a high-capacity AC/DC electrical system, permitting it to carry a variety of payloads on a single mission. The modular design of the aircraft permits rapid installation or removal of payloads to meet changing mission requirements. The ER-2 has a range beyond 3,000 miles (4800 kilometers); is capable of long flight duration and can operate at altitudes up to 70,000 feet (21.3 kilometers) if required. Operating at an altitude of 65,000 feet (19.8 kilometers) the ER-2 acquires data

  14. Decay of the neutron-rich isotope sup 171 Ho and the identification of sup 169 Dy

    SciTech Connect

    Chasteler, R.M.; Nitschke, J.M.; Firestone, R.B.; Vierinen, K.S.; Wilmarth, P.A. )

    1990-10-01

    Neutron-rich rare-earth isotopes were produced in multinucleon transfer reactions between {sup 170}Er ions and {sup nat}W targets. On-line mass separation was used together with {beta}- and {gamma}-ray spectroscopy in these studies. At mass {ital A}=169, the heaviest known dysprosium isotope, 39(8) s,{sup 169}Dy, was identified. It was observed to {beta}{sup {minus}} decay to the ground state of {sup 169}Ho or through a level at 1578 keV. In the {ital A}=171 mass chain, a partial decay scheme for 55(3)-s {sup 171}Ho was determined.

  15. Registration of ‘Dy10-DLC’ wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dy10-DLC wheat (Triticum aestivum) was developed by USDA-ARS at the Western Regional Research Center in Albany, CA. Dy10-DLC was identified from an EMS-mutagenized population of an elite hexaploid wheat variety Summit by screening M3 seeds for altered storage protein profiles using one-dimensiona...

  16. Radiative strength functions in {sup 163,164}Dy

    SciTech Connect

    Nyhus, H. T.; Siem, S.; Guttormsen, M.; Larsen, A. C.; Buerger, A.; Syed, N. U. H.; Tveten, G. M.; Voinov, A.

    2010-02-15

    The nuclei {sup 163,164}Dy have been investigated using the Oslo method on data from the pickup reaction {sup 164}Dy({sup 3}He,{alpha}{gamma}){sup 163}Dy and the inelastic scattering {sup 164}Dy({sup 3}He,{sup 3}He{sup '}{gamma}){sup 164}Dy, respectively. The radiative strength functions for both nuclei have been extracted, and a small resonance centered around E{sub {gamma}}approx =3 MeV is observed in both cases. The parameters of this so-called pygmy M1 resonance (the scissors mode) are compared with previous results on {sup 160,161,162}Dy using the Oslo method, and with data on {sup 163}Dy measured by the Prague group using the two-step cascade method. In particular, the integrated reduced transition probability B(M1arrow up) of the pygmy resonance is compared with neighboring dysprosium isotopes. We also observe an enhanced strength in the region above E{sub {gamma}}approx =5 MeV in {sup 164}Dy. Possible origins of this feature are discussed.

  17. Radiative strength functions in Dy163,164

    NASA Astrophysics Data System (ADS)

    Nyhus, H. T.; Siem, S.; Guttormsen, M.; Larsen, A. C.; Bürger, A.; Syed, N. U. H.; Tveten, G. M.; Voinov, A.

    2010-02-01

    The nuclei Dy163,164 have been investigated using the Oslo method on data from the pickup reaction Dy164(He3,αγ)Dy163 and the inelastic scattering Dy164(He3,He3'γ)Dy164, respectively. The radiative strength functions for both nuclei have been extracted, and a small resonance centered around Eγ≈3 MeV is observed in both cases. The parameters of this so-called pygmy M1 resonance (the scissors mode) are compared with previous results on Dy160,161,162 using the Oslo method, and with data on Dy163 measured by the Prague group using the two-step cascade method. In particular, the integrated reduced transition probability B(M1↑) of the pygmy resonance is compared with neighboring dysprosium isotopes. We also observe an enhanced strength in the region above Eγ≈5 MeV in Dy164. Possible origins of this feature are discussed.

  18. Room temperature Dy:YLF laser operation at 4.34 micron

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.; Allen, Roger E.

    1991-01-01

    A Dy:YLF laser operating on the 6H11/2 to 6H13/2 transition at 4.34 micron and using a laser pumping scheme is reported. This pumping scheme is necessitated by the short upper-laser-level lifetime and the small effective stimulated-emission cross section. A suitable laser for this application is the Er:YLF laser operating at 1.73 micron. A simple model that approximates Dy:YLF laser performance well is presented. Results on laser performance, including a determination of the slope efficiency and threshold as a function of the output mirror reflectivity and a correlation of the pulse length with the laser output energy, are reported. Overall laser efficiency is found to be limited primarily by the ratio of the pump wavelength to laser output wavelength and the terminated four-level laser operation. Spectroscopic results, including the measurement of the absorption spectra and the lifetimes of both the upper- and lower-laser manifolds, are given.

  19. Magnetic properties of Dy3+ ions and crystal field characterization in YF3:Dy3+ and DyF3 single crystals

    NASA Astrophysics Data System (ADS)

    Savinkov, A. V.; Korableva, S. L.; Rodionov, A. A.; Kurkin, I. N.; Malkin, B. Z.; Tagirov, M. S.; Suzuki, H.; Matsumoto, K.; Abe, S.

    2008-12-01

    The dc magnetic susceptibilities of the orthorhombic DyF3 single crystals have been measured in the temperature range between 1.8 and 300 K. The susceptibility along the b-axis does not depend on temperature below TC = 2.55 K and is equal to the demagnetizing factor of the sample, that gives evidence for the ferromagnetic phase induced by the magnetic dipole-dipole interactions between the Dy3+ ions. The saturation moment of 8.5 μB/Dy3+ along the b-axis was determined from magnetization measurements. The observed strong anisotropy of the magnetic susceptibility at low temperatures agrees with the measured anisotropic g-tensor of the ground state of impurity Dy3+ ions in YF3 single crystals. The results of measurements are interpreted in the frameworks of the crystal field theory and the mean magnetic field approximation.

  20. Experimental study of the beta-delayed proton decays of {sup 145,147}Er

    SciTech Connect

    Ma, F.; Zhou, X. H.; Zheng, Y.; Xu, S. W.; Xie, Y. X.; Chen, L.; Lei, X. G.; Guo, Y. X.; Zhang, Y. H.; Li, Z. K.; Qiang, Y. H.; Guo, S.; Wang, H. X.; Zhou, H. B.; Ding, B.; Li, G. S.; Zhang, N. T.

    2010-04-15

    The beta-delayed proton decays of {sup 145,147}Er have been studied experimentally using the {sup 58}Ni+{sup 92}Mo reaction at beam energy of 383 MeV. On the basis of a He-jet apparatus coupled with a tape transport system, the beta-delayed proton radioactivities both from the nus{sub 1/2} ground state and the nuh{sub 11/2} isomer in {sup 145,147}Er were observed by proton-gamma coincidence measurements. By analyzing the time distributions of the 4{sup +}->2{sup +}gamma transitions in the granddaughter nuclei {sup 144,146}Dy, the half-lives of 1.0+-0.3 s and 1.6+-0.2 s have been deduced for the nuh{sub 11/2} isomers in {sup 145,147}Er, respectively.

  1. 26 CFR 48.4082-2 - Diesel fuel and kerosene; notice required for dyed fuel.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... dyed fuel. 48.4082-2 Section 48.4082-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE... required for dyed fuel. (a) In general. A legible and conspicuous notice stating “DYED DIESEL FUEL... facility where it sells dyed diesel fuel for use by its buyer. A legible and conspicuous notice...

  2. 26 CFR 48.4082-2 - Diesel fuel and kerosene; notice required for dyed fuel.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... dyed fuel. 48.4082-2 Section 48.4082-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE... required for dyed fuel. (a) In general. A legible and conspicuous notice stating “DYED DIESEL FUEL... facility where it sells dyed diesel fuel for use by its buyer. A legible and conspicuous notice...

  3. 26 CFR 48.4082-2 - Diesel fuel and kerosene; notice required for dyed fuel.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... dyed fuel. 48.4082-2 Section 48.4082-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE... required for dyed fuel. (a) In general. A legible and conspicuous notice stating “DYED DIESEL FUEL... facility where it sells dyed diesel fuel for use by its buyer. A legible and conspicuous notice...

  4. 26 CFR 48.4082-2 - Diesel fuel and kerosene; notice required for dyed fuel.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... dyed fuel. 48.4082-2 Section 48.4082-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE... required for dyed fuel. (a) In general. A legible and conspicuous notice stating “DYED DIESEL FUEL... facility where it sells dyed diesel fuel for use by its buyer. A legible and conspicuous notice...

  5. Magnetocaloric Effect of RCo2 (R: Er, Ho, Dy) Compounds for Regenerative Magnetic Refrigeration

    NASA Astrophysics Data System (ADS)

    Matsumoto, Koichi; Kouen, Takaaki; Nishida, Ryouhei; Abe, Satoshi; Kamiya, Koji; Numazawa, Takenori

    2006-09-01

    Because of its high density, liquid hydrogen is one of the most promising forms of hydrogen for efficient, economic transport and storage. Magnetic refrigeration, which is based on the magnetocaloric effect of magnetic solids, has the potential to achieve high thermal efficiency and reduce the cost of hydrogen liquefaction. Magnetic properties of some candidate materials among RCo2 (R: rare earth) compounds have been studied. These materials have been found to have large magnetocaloric effects and suitable phase transition temperatures. Because the magnetocaloric effect is large only around the magnetic transition temperature, a series of magnetic materials with carefully designed transition temperatures is required.

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

    SciTech Connect

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

    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.

  7. A new method of making 164Dy metal plate targets

    NASA Astrophysics Data System (ADS)

    Sugai, Isao; Kato, Hajime

    1986-04-01

    164Dy metal plate targets of high purity for measurements of the electron neutrino mass were made successfully. The starting material 164DyF 3 was reduced to metal by the Ca reduction method with rf induction heating. The reduced metal was pressed with a hot-press device in argon gas atmosphere and rolled into plates of 35 mm × 10 mm in area by a new method of packing. The thicknesses were in the range from 150 to 230 mg/cm 2. The present method was also found suitable to make thin Dy targets of the order of 1 mg/cm 2 in thickness

  8. Two novel Dy8 and Dy11 clusters with cubane [Dy4(μ3-OH)4]8+ units exhibiting slow magnetic relaxation behaviour.

    PubMed

    Miao, Yan-Li; Liu, Jun-Liang; Li, Jin-Yan; Leng, Ji-Dong; Ou, Yong-Cong; Tong, Ming-Liang

    2011-10-21

    Two unique octa- and hendeca-nuclear dysprosium(III) clusters incorporating [Dy(4)(μ(3)-OH)(4)](8+) cubane units have been synthesized with the 1,10-phenanthroline-2,9-dicarbaldehyde dioxime (H(2)phendox) ligand and DyCl(3)·6H(2)O or Dy(OAc)(3)·4H(2)O. They are [Dy(8)(OH)(8)(phendox)(6)(H(2)O)(8)]Cl(2)(OH)(2)·18H(2)O·18MeOH (1) and [Dy(11)(OH)(11)(phendox)(6)(phenda)(3)(OAc)(3)](OH)·40H(2)O·7MeOH (2). Adjacent Dy(8) in 1 or Dy(11) in 2 motifs are packed by off-set π-π interactions of the aromatic rings on phendox(2-) to generate a 3D supramolecular architecture in the honeycomb topology and with 1D or 3D channels along the c-axis. Adsorption research shows that complex 1 has selective adsorption ability for H(2)O over small gas molecules (H(2), N(2), CO(2)). Complex 2 is stable upon the removal of guest molecules and the desolvated compound absorbed a considerable amount of CO(2). Furthermore, the oximes underwent hydrolysis to carboxylic acid and the resulting 1,10-phenanthroline-2,9-dicarboxylate link the dysprosium atoms to form a hendecanuclear cluster of 2. Magnetic studies reveal that both clusters exhibit slow magnetic relaxation behavior, expanding upon the recent reports of the pure 4f type single-molecule magnets (SMMs). PMID:21894344

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

    PubMed

    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 . PMID:26256244

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

    SciTech Connect

    Nisius, D.; Janssens, R.V.F.; Crowell, B.

    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.

  11. An oxygen-sensitive luminescent Dy(iii) complex.

    PubMed

    Nakai, Hidetaka; Seo, Juncheol; Kitagawa, Kazuhiro; Goto, Takahiro; Matsumoto, Takahiro; Ogo, Seiji

    2016-06-21

    This paper presents the first dysprosium(iii) complex, [{((MeMe)ArO)3tacn}Dy(III)(THF)] (1(Dy)), that shows oxygen-sensitive luminescence. The synthesis, structure and oxygen-sensitive luminescence properties of 1(Dy) are reported (Φ = 0.050 and τ = 17.7 μs under N2, Φ = 0.011 and τ = 4.1 μs under O2 and KSV = 305 M(-1) in THF; KSV = 0.0077%(-1) in polystyrene film). The oxygen sensitive mechanism of 1(Dy) is discussed based on the photophysical properties of the corresponding gadolinium(iii) complex, [{((MeMe)ArO)3tacn}Gd(III)(THF)]. PMID:27191980

  12. Spectroscopic and energy transfer properties of Dy3+-doped, Tb3+/Dy3+-codoped dense oxyfluoride borogermanate scintillating glasses

    NASA Astrophysics Data System (ADS)

    Sun, Xin-Yuan; Yu, Xiao-Guang; Jiang, Da-Guo; Wang, Wen-Feng; Li, Yu-Nong; Chen, Zhi-Quan; Zhou, Yun-Zhi; Yang, Qing-Mei; Kang, Zhitao

    2016-06-01

    Dy3+-, Tb3+-activated, and Tb3+/Dy3+-coactivated oxyfluoride borogermanate scintillating glasses with the density of about 6.50 g/cm3 were successfully synthesized by a melt-quenching method. The structure and optical properties including transmittance, photoluminescence (excitation and emission spectra), photoluminescence decay, and X-ray excited luminescence (XEL) behaviors were studied in detail. Our results reveal that the energy transfer efficiency from Dy3+ to Tb3+ ions increases with an increase of Tb3+ concentration. The energy transfer mechanism is determined to be electric dipole-dipole interaction. However, the XEL intensity of Tb3+ decreases with the incorporation of sensitizer Dy3+ into borogermanate scintillating glass, which may result from the different mechanisms under ultraviolet light and X-ray excitation.

  13. Ge Nanocluster Enhanced Er Photoluminescence

    NASA Astrophysics Data System (ADS)

    Guzman, Julian; Chrzan, Daryl C.; Haller, Eugene E.

    2010-03-01

    We investigated the enhancement of the Er^3+ photoluminescence (PL) at 1540 nm by the incorporation of Ge nanoclusters into Er-doped silica using ion beams. We found that the Er^3+ PL enhancement is due to the presence of Ge and not to the radiation damage from the ion-implantation process. We determined that the Er^3+ PL depends on the Ge content, postgrowth annealing, and crystallinity of the Ge nanoclusters. Furthermore, we observed that the Er^3+ PL signal is maximized after annealing at 685 C for 1 h. This is the temperature at which Ge nanoclusters begin to crystallize. Transmission electron microscopy studies were conducted to determine the size distribution of the Ge nanoclusters. Moreover, extended X-ray absorption fine structure measurements performed at the Ge-K and Er-LIII edges revealed that there is negligible Ge-Er bonding. This suggests that Er is either fully oxidized or that it is not located in the Ge nanoclusters. Therefore, we believe that the energy transfer process from the Ge nanoclusters to the Er ions occurs through a non-optical resonant dipole transfer (F"orster ProcessfootnotetextT. F"orster, Discuss. Faraday Soc. 27, 7 (1959). similar to what has been proposed for the Si nanocrystal case.footnotetextM. Fujii, M. Yoshida, S. Hayashi, and K. Yamamoto, J. Appl. Phys. 84, 4525 (1998).

  14. Protein folding in the ER.

    SciTech Connect

    Stevens, F. J.; Argon, Y.; Biosciences Division; Univ. of Chicago

    1999-10-01

    The endoplasmic reticulum (ER) is a major protein folding compartment for secreted, plasma membrane and organelle proteins. Each of these newly-synthesized polypeptides folds in a deterministic process, affected by the unique conditions that exist in the ER. An understanding of protein folding in the ER is a fundamental biomolecular challenge at two levels. The first level addresses how the amino acid sequence programs that polypeptide to efficiently arrive at a particular fold out of a multitude of alternatives, and how different sequences obtain similar folds. At the second level are the issues introduced by folding not in the cytosol, but in the ER, including the risk of aggregation in a molecularly crowded environment, accommodation of post-translational modifications and the compatibility with subsequent intracellular trafficking. This review discusses both the physicochemical and cell biological constraints of folding, which are the challenges that the ER molecular chaperones help overcome.

  15. Investigations of the effect of nonmagnetic Ca substitution for magnetic Dy on spin-freezing in Dy2Ti2O7

    NASA Astrophysics Data System (ADS)

    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.

  16. 26 CFR 48.6715-1 - Penalty for misuse of dyed fuel.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 16 2011-04-01 2011-04-01 false Penalty for misuse of dyed fuel. 48.6715-1... of Special Application to Retailers and Manufacturers Taxes § 48.6715-1 Penalty for misuse of dyed... of any dye or marking done pursuant to § 48.4082-1 in any dyed fuel, then section 6715(a)(3)...

  17. 26 CFR 48.6715-1 - Penalty for misuse of dyed fuel.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 16 2012-04-01 2012-04-01 false Penalty for misuse of dyed fuel. 48.6715-1... of Special Application to Retailers and Manufacturers Taxes § 48.6715-1 Penalty for misuse of dyed... of any dye or marking done pursuant to § 48.4082-1 in any dyed fuel, then section 6715(a)(3)...

  18. 26 CFR 48.6715-1 - Penalty for misuse of dyed fuel.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 16 2013-04-01 2013-04-01 false Penalty for misuse of dyed fuel. 48.6715-1... of Special Application to Retailers and Manufacturers Taxes § 48.6715-1 Penalty for misuse of dyed... of any dye or marking done pursuant to § 48.4082-1 in any dyed fuel, then section 6715(a)(3)...

  19. 26 CFR 48.6715-1 - Penalty for misuse of dyed fuel.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Penalty for misuse of dyed fuel. 48.6715-1... of Special Application to Retailers and Manufacturers Taxes § 48.6715-1 Penalty for misuse of dyed... of any dye or marking done pursuant to § 48.4082-1 in any dyed fuel, then section 6715(a)(3)...

  20. Spectroscopic characteristics of GdVO4: Dy3+ crystal

    NASA Astrophysics Data System (ADS)

    Ning, Kaijie; He, Xiaoming; Zhang, Lianhan; Liu, Youchen; Yin, Jigang; Zhang, Peixing; Chen, Guangzhu; Wang, Xiangyong; Chen, Zhe; Shi, Chunjun; Hong, Jiaqi; Hang, Yin

    2014-11-01

    Room temperature optical absorption, emission spectrum of GdVO4: Dy3+ crystal grown by Czochralski (CZ) method were measured and analyzed. Spectral parameters were calculated in the framework of the Judd-Ofelt theory. The GdVO4: Dy3+ crystal showed two intense and relatively broad absorption bands in UV wavelength range centered at 390 and 453 nm and two prominent emission peaks located at blue 485 and yellow 575 nm. The corresponding absorption and emission cross sections were estimated and the luminescence decay curve was analyzed. Optical spectroscopy investigations indicate that GdVO4: Dy3+ crystal would be a promising blue and yellow solid state laser material.

  1. Two distinct Dy-isophthalates induced by different solvents

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Huang, Yuan-Yuan; Yao, Yuan-Gen

    2012-09-01

    Two distinct Dy-isophthalates, [Dy4(m-BDC)6(H2O)4(DMF)]nṡ2n(H2O)ṡn(DMF) 1 and [Dy2(m-BDC)3(H2O)(DMA)]nṡ3n(H2O)ṡ2n(DMA) 2 (DMF = N,N'-Dimethylformamide, DMA = N,N'-Dimethylacetamide), which were induced by different solvents under the same hydrothermal conditions, were obtained. Single-crystal analysis revealed that compounds 1 and 2 feature two-dimensional (2D) layer structure with opened widows occupied by guests (DMF for 1 and DMA for 2). In addition, a rare hybrid [(H2O)3(DMA)2] pentamer was found in 2. Furthermore, thermal analyses of 1-2 were also investigated.

  2. Broad Feshbach resonances in collisions of Dy atoms

    NASA Astrophysics Data System (ADS)

    Julienne, P.; Jachymski, K.; Maier, T.; Ferrier-Barbut, I.; Karan, H.; Schmitt, M.; Wenzel, M.; Wink, C.; Pfau, T.

    2016-05-01

    RF spectroscopy of weakly bound dimers of ultra cold bosonic Dy atoms gives evidence for the emergence of a universal s-wave halo state in a background of chaotic background resonance states. The halo state is associated with a broad magnetic Feshbach resonance. Using a coupled channels theory taking into account the short ranged van dear Waals interaction and a correction due to the strong dipole moment of Dy, we are able to extract the scattering length as a function of magnetic field tuning near two such broad resonances. These results offer prospects for tuning the interactions of Dy atoms in a regime where three-body losses are not too strong. Supported in part by the DFG, the Foundation for Polish Science International Ph. D Projects Programme, and an AFOSR MURI.

  3. Crystal structure and Mössbauer studies of the isotypic Fe{sub 6}-cluster compounds RE{sub 15}[Fe{sub 8}C{sub 25}], RE=Dy, Ho

    SciTech Connect

    Davaasuren, Bambar; Dashjav, Enkhtsetseg; Kreiner, Guido; Borrmann, Horst; Weber, Sven-Ulf; Becker, Klaus-Dieter; Jochen Litterst, Fred; Kniep, Rüdiger

    2015-05-15

    The carboferrates RE{sub 15}[Fe{sub 8}C{sub 25}] (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 Er{sub 15}[Fe{sub 8}C{sub 25}] (hP48, P321). The main feature of the crystal structure is given by Fe{sub 6} cluster units characterized by covalent Fe–Fe bonding interactions. {sup 57}Fe Mössbauer spectra of Dy{sub 15}[Fe{sub 8}C{sub 25}] 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. - Graphical abstract: Fe{sub 6}-cluster in the crystal structure of RE{sub 15}[Fe{sub 8}C{sub 25}], RE=Dy, Ho. - Highlights: • New carboferrates RE{sub 15}[Fe{sub 8}C{sub 25}] with RE=Dy, Ho have been synthesized. • The crystal structures were refined using single crystal X-ray data. • An orientational relationship between Fe{sub 6}-clusters and Fe in γ-Fe is outlined. • {sup 57}Fe Mössbauer spectra are in agreement with structural data from X-rays. • Magnetic hyperfine fields below 50 K are explained by dipolar fields from Dy atoms.

  4. Dy-Free Nd-Fe-B Based Permanent Magnets

    NASA Astrophysics Data System (ADS)

    Pathak, Arjun; Khan, Mahmud; Gschneidner, Karl, Jr.; McCallum, Ralph; Pecharsky, Vitalij

    2015-03-01

    Nd2Fe14B based permanent magnets are the current state of the art for high performance magnets. The prototype crystallize in the P42 / mnm tetragonal crystal structure, where the Nd atoms occupy the 4f and 4gsites, Fe atoms occupy six different atomic sites (16k1, 16k2, 8j1, 8j2, 4e, 4c), and B occupies only the 4g site. The leading contribution to the magnetocrystalline anisotropy in Nd2Fe14B energy comes from the Nd ions, which strongly prefer a c-axis alignment at ambient temperature. Nd2Fe14B permanent magnet has excellent magnetic properties at room temperature but has poor high temperature properties (T>400 K). A small amount of Dy (up to 10%) is substituted for Nd in Nd2Fe14B to increase the high temperature performance. Although Dy containing Nd2Fe14B magnets are desired for high temperature applications, the high price and limited supply of Dy urges the development of Dy-free permanent magnets. Here, we discuss the magnetic properties of several Dy-free Nd-Fe-B based nanostructured magnets and propose alternatives for Dy-based Nd2Fe14B permanent magnets for high temperature applications such as electric drive motors and wind turbines. This work was supported by the U.S.DOE, ARPA-E, Rare Earth Alternatives in Critical Technologies for Energy (REACT). The research was performed at the Ames Laboratory which is operated for the U.S. DOE by Iowa State University under contract #DE-AC02-07CH11358.

  5. Optical spectroscopic study on new magnetoelectric hexagonal REMnO3 (RE=Gd, Tb, Dy, and Ho) thin films

    NASA Astrophysics Data System (ADS)

    Choi, Woo Seok; Seo, Sung Seok A.; Lee, Jung Hyuk; Lee, Daesu; Noh, Tae Won; Lee, Yunsang

    2007-03-01

    Recently, magnetoelectric effects in various oxides have been attracting lots of attentions and are being extensively investigated due to their intriguing couplings between the magnetic and electric order parameters. Here we report optical spectroscopic investigations on new hexagonal REMnO3 (RE = Gd, Tb, Dy, and Ho) thin films, which are fabricated by epi-stabilization technique [1]. From the in-plane optical conductivity spectra of the hexagonal REMnO3, we observe a dramatic increase of the optical transition related to Mn 3d a1g energy level, as the ionic radius of the R ion increases. The optical transition at 1.64 eV for DyMnO3 shifts to 1.67 and 1.81 for TbMnO3 and GdMnO3 respectively. For natural hexagonal REMnO3 (RE = Y, Er, Lu, and Sc) with smaller ionic sizes, the same optical transitions occur at ˜1.6 eV. The large peak shift in new hexagonal REMnO3 is understood by local flattening of Mn-O bipyramid, which will enhance the crystal field energy of a1g, as the RE ionic size increases. [1] J. H. Lee et al., Adv. Mat., to be published (2006).

  6. Concomitant charge-density-wave and unit-cell-doubling structural transitions in Dy5Ir4Si10

    NASA Astrophysics Data System (ADS)

    Lee, M. H.; Chen, C. H.; Tseng, C. M.; Lue, C. S.; Kuo, Y. K.; Yang, H. D.; Chu, M.-W.

    2014-05-01

    The tetragonal rare-earth transition-metal silicide system with three-dimensional crystallographic structure R5T4Si10, where R is Dy, Ho, Er, Tm, and Lu, and T=Ir and Rh, has been shown to exhibit fascinating charge-density-wave (CDW) phase transitions, a phenomenon largely found in otherwise low-dimensional systems. In this study, we report the investigations of CDW in Dy5Ir4Si10 at different temperatures using transmission electron microscopy techniques including electron diffraction and dark-field imaging. Incommensurate superlattice spots along the c axis were observed in the electron-diffraction patterns when the sample was cooled below the CDW transition temperature at ˜208 K. CDW becomes commensurate with further cooling and configurations of CDW dislocations convincingly show that the CDW phase transition is accompanied by a concomitant cell-doubling crystallographic structural phase transition. Intriguingly, the cell-doubling transition is featured by a broken inversion symmetry along the c axis and a disparity in the CDW-modulation vectors with opposite signs, which gives rise to two sets of CDW domains with reversed contrasts. The profound physics underlining this notable domain-contrast behavior is discussed.

  7. Mueller matrix ellipsometry studies of the optical phonons and crystal field excitations in multiferroic orthoferrites RFeO3 (R=Tb,Dy)

    NASA Astrophysics Data System (ADS)

    Martinez, V. A.; Stanislavchuk, T. N.; Sirenko, A. A.; Litvinchuk, A. P.; Wang, Yazhong; Cheong, S. W.

    Optical properties of multiferroic orthoferrites RFeO3 (R=Tb,Dy) bulk crystals have been studied in the far-infrared range from 50 to 1000 cm-1 and temperatures from 7 K to 300 K. Mueller matrix and rotating analyzer ellipsometry measurements were carried out at the U4IR beamline of the National Synchrotron Light Source at Brookhaven National Lab. Optical phonon spectra and crystal field excitations were measured for all three orthorhombic axes of RFeO3. In the experimental temperature dependencies of the phonon frequencies we found non-Grüneisen behavior caused by the electron-phonon and spin-phonon interactions. We determined the symmetries and selection rules for the crystal field transitions in Tb3+ and Dy3+ ions. Magnetic field dependencies of the optical spectra allowed us to determine anisotropy of the crystal field g-factors for Tb3+ and Dy3+ ions. This Project is supported by collaborative DOE Grant DE-FG02-07ER46382 between Rutgers U. and NJIT. Use of NSLS-BNL was supported by DOE DE-AC02-98CH10886. V.A. Martinez was supported by NEU NSF-1343716.

  8. Lifetimes and electromagnetic transition strength in 157Dy

    NASA Astrophysics Data System (ADS)

    Gladnishki, K. A.; Petkov, P.; Dewald, A.; Jolie, J.; Möller, O.; Saha, B.; Fitzler, A.; Jessen, K.; Tonev, D.; Klug, T.; Heinze, S.; von Brentano, P.; Rainovski, G.; Trichkova, M.; Bazzacco, D.; Ur, C. A.; Farnea, E.; Axiotis, M.; Lunardi, S.; de Angelis, G.; Napoli, D. R.; Marginean, N.; Martinez, T.; Caprio, M. A.

    2016-06-01

    Excited states in 157Dy have been studied by γ-γ coincidence measurements via the reaction 124Sn(36S,3n) at a beam energy of 155MeV. Lifetimes of the relatively lower-spin states in 157Dy were measured by means of the Recoil Distance Dopplershift technique in the coincidence mode. The experiment was performed at the Laboratori Nazionali di Legnaro with the GASP array and the Cologne plunger device. With the same setup a Doppler- shift attenuation (DSA) lifetime measurement was performed for the higher spin states. The Differential decay-curve method was applied for the lifetime determination.

  9. Sternohyoid muscle fatigue properties of dy/dy dystrophic mice, an animal model of merosin-deficient congenital muscular dystrophy.

    PubMed

    van Lunteren, Erik; Moyer, Michelle

    2003-10-01

    Humans with merosin-deficient congenital muscular dystrophy have both sucking problems during infancy and sleep-disordered breathing during childhood. We hypothesized that merosin-deficient pharyngeal muscles fatigue faster than normal muscles. This was tested in vitro using sternohyoid muscle from an animal model of this disease, the dy/dy dystrophic mouse. Isometric twitch contraction and half-relaxation times were similar for dy/dy and normal sternohyoid. However, rate of force loss during repetitive 25-Hz train stimulation was markedly diminished in dystrophic compared with normal sternohyoid muscle. Furthermore, force potentiation, which occurred during the early portion of the fatigue-inducing stimulation, had a longer duration in dystrophic compared with normal muscle (approximately 60 versus 20 s). As a result of these two processes, at the end of 2 min of stimulation, force of dystrophic muscle had decreased by 8 +/- 5% and that of normal muscle by 69 +/- 4% (p < 0.0001). The potassium-channel blocker, 3,4-diaminopyridine, increased force of dy/dy sternohyoid muscle during twitch and 25-Hz contractions by 148 +/- 20% (p < 0.00001) and 109 +/- 18% (p < 0.00002), respectively. During repetitive 25-Hz stimulation, force of 3,4-diaminopyridine-treated dystrophic muscle remained significantly higher than that of untreated muscle, despite the early force potentiation being eliminated and fatigue being accelerated. Thus, merosin deficiency reduces fatigue and prolongs the duration of force potentiation. The latter alterations may partially preserve the integrity of upper airway muscle function, without which the severity of pharyngeal complications (feeding problems, sleep-related respiratory dysfunction) might be even more pronounced in the human merosin-deficient congenital muscular dystrophies. PMID:12840158

  10. Structural and phase dependent thermo and photoluminescent properties of Dy(OH){sub 3} and Dy{sub 2}O{sub 3} nanorods

    SciTech Connect

    Chandrasekhar, M.; Sunitha, D.V.; Dhananjaya, N.; Nagabhushana, H.; Sharma, S.C.; Nagabhushana, B.M.; Shivakumara, C.; Chakradhar, R.P.S.

    2012-08-15

    Graphical abstract: Packing diagram of (a) hexagonal Dy(OH){sub 3} and (b) cubic Dy{sub 2}O{sub 3} nanorods. Highlights: ► Hexagonal Dy(OH){sub 3} and Dy{sub 2}O{sub 3} nanorods were prepared by hydrothermal route. ► Phase dependent PL and TL studies were carried out. ► The kinetic parameters such as activation energy (E), order of kinetics (b), and frequency factor (s) were estimated using peak shape method. ► Linear response of cubic Dy{sub 2}O{sub 3} phase is useful for its application in dosimetry. -- Abstract: Hexagonal Dy(OH){sub 3} and cubic Dy{sub 2}O{sub 3} nanorods were prepared by hydrothermal method. Dy(OH){sub 3} nanorods was directly obtained at 180 °C for 20 h after hydrothermal treatment whereas subsequently heat treatment at 750 °C for 2 h gives pure cubic Dy{sub 2}O{sub 3}. SEM micrographs reveal that needle shaped rods with different sizes were observed in both the phases. TEM results also confirm this. The TL response of hexagonal Dy(OH){sub 3} and cubic Dy{sub 2}O{sub 3} nanorods have been analyzed for γ-irradiation over a wide range of exposures (1–5 kGy). TL glow peak intensity increases with γ dose in both the phases. The activation energy (E), order of kinetics (b), and frequency factor (s) for both the phases have been determined using Chen's peak shape method. The simple glow curve shape, structure and linear response to γ-irradiation over a large span of exposures makes the cubic Dy{sub 2}O{sub 3} as a useful dosimetric material to estimate high exposures of γ-rays.

  11. Effect of B³⁺-N³⁻ on YAG:Dy thermographic phosphor luminescence.

    PubMed

    Kwong, Wing Yin; Steinberg, Adam; Chin, Ya Huei

    2014-11-01

    The use of thermographic phosphors for high-temperature (>1000  K) thermometry currently is limited by loss of signal due to thermal quenching. This work demonstrates a new phosphor generated by substituting tetrahedral site Al(3+)-O(2-) in YAG:Dy with B(3+)-N(3-) to produce YABNG:Dy. Conventional YAG:Dy and YABNG:Dy phosphors were synthesized using identical solgel synthesis techniques. X-ray diffraction measurements showed that both had nearly pure crystalline phases, with a minor secondary yttrium-aluminum-monoclinic (YAM) phase present in the YABNG:Dy. The YABNG:Dy sample had a larger and more spherical primary grain than did the YAG:Dy in scanning electron microscopy images. Tests of the thermal response showed that the YABNG:Dy had much stronger phosphorescence emissions than did YAG:Dy, likely due to the morphological differences. Furthermore, the onset of thermal quenching was delayed by approximately 100 K for YABGN:Dy compared to YAG:Dy, and the rate of signal decrease with temperature was reduced. This resulted in greater signal-to-noise ratios and less uncertainty in the temperature measurements, particularly at high temperatures. PMID:25361305

  12. Decomposition of DyF3 and its effect on magnetic performance of DyF3-doped Nd-Fe-B-type hot-deformed magnet

    NASA Astrophysics Data System (ADS)

    Kim, J. Y.; Kwon, H. W.; Lee, J. G.; Yu, J. H.

    2015-05-01

    Decomposition of DyF3 and its effect on the magnetic performance of the hot-pressed compact and die-upset magnet of melt-spun Nd-Fe-B-type material were investigated. DyF3 was thermally decomposed above 660 °C, and this decomposition was linked closely to the coercivity enhancement. When the DyF3 doped flakes were hot-pressed above the decomposition temperature of DyF3, the diffusion of Dy into the flakes was promoted, and leading to profound coercivity enhancement. Coercivity of the hot-pressed magnet was further enhanced by post-hot-press annealing, and coercivity as high as 24.5 kOe was obtained after the optimum annealing. The DyF3 doped hot-deformed magnet exhibited enhanced magnetic performance (iHc = 17.5 kOe, Br = 12.8 kG, (BH)max = 37.6 MGOe) with respect to the un-doped magnet without sacrificing significant remanence. Coercivity was improved by 30%. In magnet in which the decomposition of DyF3 and Dy diffusion were fully accomplished, the region originally occupied by added DyF3 was completely replaced by NdF3.

  13. Highly conserved salt bridge stabilizes a proteinase K subfamily enzyme, Aqualysin I, from Thermus aquaticus YT-1

    PubMed Central

    2014-01-01

    The proteinase K subfamily enzymes, thermophilic Aqualysin I (AQN) from Thermus aquaticus YT-1 and psychrophilic serine protease (VPR) from Vibrio sp. PA-44, have six and seven salt bridges, respectively. To understand the possible significance of salt bridges in the thermal stability of AQN, we prepared mutant proteins in which amino acid residues participating in salt bridges common to proteinase K subfamily members and intrinsic to AQN were replaced to disrupt the bridges one at a time. Disruption of a salt bridge common to proteinase K subfamily enzymes in the D183N mutant resulted in a significant reduction in thermal stability, and a massive change in the content of the secondary structure was observed, even at 70°C, in the circular dichroism (CD) analysis. These results indicate that the common salt bridge Asp183-Arg12 is important in maintaining the conformation of proteinase K subfamily enzymes and suggest the importance of proximity between the regions around Asp183 and the N-terminal region around Arg12. Of the three mutants that lack an AQN intrinsic salt bridge, D212N was more prone to unfolding at 80°C than the wild-type enzyme. Similarly, D17N and E237Q were less thermostable than the wild-type enzyme, although this may be partially due to increased autolysis. The AQN intrinsic salt bridges appear to confer additional thermal stability to this enzyme. These findings will further our understanding of the factors involved in stabilizing protein structure. PMID:25136511

  14. Search for neutrinoless double-electron capture of 156Dy

    NASA Astrophysics Data System (ADS)

    Finch, S. W.; Tornow, W.

    2015-12-01

    Background: Multiple large collaborations are currently searching for neutrinoless double-β decay, with the ultimate goal of differentiating the Majorana-Dirac nature of the neutrino. Purpose: Investigate the feasibility of resonant neutrinoless double-electron capture, an experimental alternative to neutrinoless double-β decay. Method: Two clover germanium detectors were operated underground in coincidence to search for the de-excitation γ rays of 156Gd following the neutrinoless double-electron capture of 156Dy. 231.95 d of data were collected at the Kimballton underground research facility with a 231.57 mg enriched 156Dy sample. Results: No counts were seen above background and half-life limits are set at O (1016-1018) yr for the various decay modes of 156Dy. Conclusion: Low background spectra were efficiently collected in the search for neutrinoless double-electron capture of 156Dy, although the low natural abundance and associated lack of large quantities of enriched samples hinders the experimental reach.

  15. Studies of normal deformation in {sup 151}Dy

    SciTech Connect

    Nisius, D.; Janssens, R.V.F.; Crowell, B.

    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.

  16. Magnetoelastic vibration damping properties of TbDy alloys

    NASA Technical Reports Server (NTRS)

    Dooley, J. A.; Good, N. R.; White, C. V.; Leland, R. S.

    2002-01-01

    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 q > 0.05 at 0.01 Hz and q > 0.1 at higher frequencies from 0.6-1.5 kHz.

  17. LOFTrelated semiscale test scene. Water has been dyed red. Hot ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LOFT-related semiscale test scene. Water has been dyed red. Hot steam blowdown exits semiscale at TAN-609 at A&M complex. Edge of building is along left edge of view. Date: 1971. INEEL negative no. 71-376 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

  18. Magnetic Behavior of a Dy8 Molecular Nanomagnet

    NASA Astrophysics Data System (ADS)

    Zhang, Qing; Sarachik, Myriam; Baker, Michael; Chen, Yizhang; Kent, Andrew; Stamatatos, Theocharis

    2015-03-01

    As part of a study of quantum tunneling in a newly synthesized family of dysprosium-based molecular magnets that exhibit a chiral spin structure, we report initial investigations of the magnetic response of a Dy8 cluster with the formula (Et4N)4[Dy8O(nd)8(NO3)10(H2O)2] .2MeCN. The molecular complex contains triangular arrangements of exchange coupled Dy(III) ions. The compound forms an approximate snub-square Archimedean lattice unit. The measured magnetization of this network of four triangles suggests the presence of multiple spin chiral vortexes. Single crystal susceptibility and magnetization measurements indicate the presence of a hard-axis direction and an easy plane. These principal orientations have been investigated in magnetic fields up to 5 Tesla for temperatures between 1.8 and 100 K using a SQUID-based Quantum Design MPMS magnetometer. Complex easy plane magnetic hysteresis loops emerge at lower temperatures measured using Hall probe magnetometry at sub 1 K temperatures. The analysis of these measurements will be discussed and compared with results of theoretical calculations. Work supported by ARO W911NF-13-1-1025 (CCNY), NSF-DMR-1309202 (NYU); the synthesis of the Dy8 cluster was supported by NSERC (Discovery grant to Th.C.S.).

  19. Effect of Dy/Nd double layer on coercivity in Nd-Fe-B thin films

    SciTech Connect

    Koike, K. Umezawa, J.; Ishikawa, H.; Ogawa, D.; Mizuno, Y.; Kato, H.; Miyazaki, T.; Ando, Y.

    2014-05-07

    The Nd-Fe-B (t{sub NFB} = 30 nm)/[Dy (t{sub Dy} nm)/Nd (t{sub Nd} nm)] (t{sub Dy/Nd} = 20 nm) (thickness t{sub Dy} = 0–10 nm) thin films were deposited on Al{sub 2}O{sub 3}(0001) substrate and subsequently in-situ annealed at 470 °C. As-deposited Nd-Fe-B thin films with a highly perpendicular orientation of c-axis were deposited by introducing bcc-Mo(111) single crystal buffer layer. After post-annealing, the grain size of the Nd-Fe-B/Dy/Nd thin films with the t{sub Dy} = 10 nm and t{sub Nd} = 10 nm becomes large due to the Dy and the Nd atoms thermal diffusion, while DyFe{sub 2} and Dy oxide compounds are formed in Nd-Fe-B layers, which is confirmed by means of a combination of atomic force microscopy observation and X-ray diffraction measurement. The H{sub c} of Nd-Fe-B/Dy/Nd thin films with the t{sub Dy} = 10 nm and t{sub Nd} = 10 nm was approximately the same value of the Nd-Fe-B thin films without Dy/Nd double layer annealed at 470 °C. On the other hand, H{sub c} is enhanced to be about 22.1 kOe in the annealed Nd-Fe-B/Dy/Nd films with the t{sub Dy} = 0.8 nm and t{sub Nd} = 19.2 nm.

  20. The Effect of Strain on the Magnetoelastic Properties of b-Axis-Oriented Dy Thin Films

    NASA Astrophysics Data System (ADS)

    Ritley, K. A.; Flynn, C. P.

    1998-03-01

    Transitions between magnetic phases in rare earths cause large strictions, so that the effect of epitaxy on the phase diagram is large and easily-studied. During the past decade thin films of rare earth metals grown as hcp (0001)-oriented single-crystals have revealed strong effects both of epitaxial strain and of epitaxial clamping. Studies of these effects have heretofore only been possible for the (0001) and (1bar102) orientations, and by growth on single-crystal substrates of Y. (R. Du, F. Tsui, C. P. Flynn, Phys. Rev. B) 38, 2941 (1988); K. Theis-Broehl, K. Ritley, C. P. Flynn, K. Hamacher, H. Kaiser, J. J. Rhyne, J. App. Phys. 79, 4779 (1996) A new MBE protocol has been developed to routinely grow single crystal RE thin films and superlattices with the hcp (10bar10)-axis normal to the growth plane, using a series of buffer layers on M-plane sapphire, including Ta, Ti, and a graded-composition TiZr alloy. To explore the anisotropy of epitaxial clamping and strain on the magnetic phase diagram, thin films of strained Dy have been grown on compositionally-tuned Y-Lu alloys. The structural properties of these samples have been measured by x-ray diffraction and AFM. The magnetic properties, obtained via SQUID-magnetometry, will be discussed, with an emphasis on structural and magnetoelastic contributions to the observed magnetic properties. Research supported by NSF-DMR-9424339 and by DOE DEFG02- 96ER45439.

  1. Basidiomycete DyPs: Genomic diversity, structural-functional aspects, reaction mechanism and environmental significance.

    PubMed

    Linde, Dolores; Ruiz-Dueñas, Francisco J; Fernández-Fueyo, Elena; Guallar, Victor; Hammel, Kenneth E; Pogni, Rebecca; Martínez, Angel T

    2015-05-15

    The first enzyme with dye-decolorizing peroxidase (DyP) activity was described in 1999 from an arthroconidial culture of the fungus Bjerkandera adusta. However, the first DyP sequence had been deposited three years before, as a peroxidase gene from a culture of an unidentified fungus of the family Polyporaceae (probably Irpex lacteus). Since the first description, fewer than ten basidiomycete DyPs have been purified and characterized, but a large number of sequences are available from genomes. DyPs share a general fold and heme location with chlorite dismutases and other DyP-type related proteins (such as Escherichia coli EfeB), forming the CDE superfamily. Taking into account the lack of an evolutionary relationship with the catalase-peroxidase superfamily, the observed heme pocket similarities must be considered as a convergent type of evolution to provide similar reactivity to the enzyme cofactor. Studies on the Auricularia auricula-judae DyP showed that high-turnover oxidation of anthraquinone type and other DyP substrates occurs via long-range electron transfer from an exposed tryptophan (Trp377, conserved in most basidiomycete DyPs), whose catalytic radical was identified in the H2O2-activated enzyme. The existence of accessory oxidation sites in DyP is suggested by the residual activity observed after site-directed mutagenesis of the above tryptophan. DyP degradation of substituted anthraquinone dyes (such as Reactive Blue 5) most probably proceeds via typical one-electron peroxidase oxidations and product breakdown without a DyP-catalyzed hydrolase reaction. Although various DyPs are able to break down phenolic lignin model dimers, and basidiomycete DyPs also present marginal activity on nonphenolic dimers, a significant contribution to lignin degradation is unlikely because of the low activity on high redox-potential substrates. PMID:25637654

  2. Terahertz magnetization dynamics induced by femtosecond resonant pumping of Dy3 + subsystem in the multisublattice antiferromagnet DyFeO3

    NASA Astrophysics Data System (ADS)

    Mikhaylovskiy, R. V.; Huisman, T. J.; Popov, A. I.; Zvezdin, A. K.; Rasing, Th.; Pisarev, R. V.; Kimel, A. V.

    2015-09-01

    Resonant optical pumping of f -f electronic transitions in the Dy3 + subsystem with femtosecond laser pulses in the multisublattice antiferromagnet DyFeO3 produces a strongly pronounced effect on the induced magnetization dynamics. Analyzing the polarization and spectral properties of the emitted THz radiation, we infer that the resonant pumping magnetizes the partially ordered Dy3 + ions on a femtosecond time scale with the induced longitudinal change of the magnetization reaching almost 1 % . We also show that for laser photon energies close to the f -f resonance of Dy3 + ions, a minimum in the efficiency of spin-wave excitation in the Fe3 + subsystem via the inverse Faraday effect is observed. This observation reveals that the resonant photo-induced magnetization in the Dy3 + subsystem and the off-resonant excitation of spin waves in the Fe3 + subsystem are intrinsically competing processes.

  3. A PERIOD INVESTIGATION OF THE SX PHOENICIS STAR DY PEGASI

    SciTech Connect

    Li, L.-J.; Qian, S.-B.

    2010-06-15

    We measure two new times of light maximum of the SX Phoenicis star DY Pegasi in 2008 December and collect 410 pe/CCD times of light maximum that had been published. These data could be modeled with a nonlinear fit including a continuously decreasing period change (dP/dt = -9.04 x 10{sup -12} days day{sup -1}) and a periodic change with a period of 42.2 yr. If this periodic change is caused by the light traveling time effect of an orbital motion of DY Pegasi in a binary system, the deduced mass of the companion could be 0.028 M{sub sun} and it is probably a brown dwarf.

  4. Magnetic properties of Dy2Ti2O7

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1973-01-01

    Measurements were made of the magnetization, differential magnetic susceptibility, and magnetic entropy of powered samples of Dy2Ti2O7. The saturation magnetic moment is 4.7 + or - 0.2 Bohr magnetons per Dy ion, instead of 10 as predicted by Hund's rules. A temperature-independent magnetization is observed in the saturation region. Absolute values of magnetic entropy have been obtained for temperatures from 1.25 to 20 K, in applied fields up to 10.4 tesla. The magnetic entropy approaches a maximum value consistent with a ground-state multiplicity of 2. Low field magnetization and differential susceptibility data show a transition to antiferromagnetism near 1.35 K. A construction of the magnetic specific heat from the zero field entropy shows an anomaly near the same temperature.

  5. Ames ER-2 ozone measurements

    NASA Technical Reports Server (NTRS)

    Pearson, R., Jr.; Vedder, James F.; Starr, W. L.

    1990-01-01

    The objective of this research is to study ozone (O3) in the stratosphere. Measurements of the ozone mixing ratio at 1 s intervals are obtained with an ultraviolet photometer which flies on the ER-2 aircraft. The photometer determines the amount of ozone in air by measuring the transmission of ultraviolet light through a fixed path with and without ambient O3 present.

  6. ERS-1 SAR data processing

    NASA Technical Reports Server (NTRS)

    Leung, K.; Bicknell, T.; Vines, K.

    1986-01-01

    To take full advantage of the synthetic aperature radar (SAR) to be flown on board the European Space Agency's Remote Sensing Satellite (ERS-1) (1989) and the Canadian Radarsat (1990), the implementation of a receiving station in Alaska is being studied to gather and process SAR data pertaining in particular to regions within the station's range of reception. The current SAR data processing requirement is estimated to be on the order of 5 minutes per day. The Interim Digital Sar Processor (IDP) which was under continual development through Seasat (1978) and SIR-B (1984) can process slightly more than 2 minutes of ERS-1 data per day. On the other hand, the Advanced Digital SAR Processore (ADSP), currently under development for the Shuttle Imaging Radar C (SIR-C, 1988) and the Venus Radar Mapper, (VMR, 1988), is capable of processing ERS-1 SAR data at a real time rate. To better suit the anticipated ERS-1 SAR data processing requirement, both a modified IDP and an ADSP derivative are being examined. For the modified IDP, a pipelined architecture is proposed for the mini-computer plus array processor arrangement to improve throughout. For the ADSP derivative, a simplified version is proposed to enhance ease of implementation and maintainability while maintaing real time throughput rates. These processing systems are discussed and evaluated.

  7. ERS Focus On: Educating Boys

    ERIC Educational Resources Information Center

    Clarke, Suzanne

    2007-01-01

    This issue of "Focus On" examines where boys are underachieving and some possible reasons for their under-achievement, including biological and environmental factors. It also offers strategies that teachers can employ in their classrooms in order to address the educational needs of boys. Books in Brief; Web Resources; and Related ERS Resources are…

  8. High-field magnetization of Dy2O3

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1974-01-01

    The magnetization of powdered samples of Dy2O3 has been measured at temperatures between 1.45 deg and 4.2 K, in applied magnetic fields ranging to 7 Teslas. A linear dependence of magnetization on applied field is observable in high field region, the slope of which is independent of temperature over the range investigated. The extrapolated saturation magnetic moment is 2.77 + or - 0.08 Bohr magnetons per ion.

  9. High-field magnetization of Dy2O3

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1974-01-01

    The magnetization of powdered samples of Dy2O3 has been measured at temperatures between 1.45 and 4.2 K, in applied magnetic fields ranging to 70 kilogauss. A linear dependence of magnetization on applied field is observable in the high-field region, the slope of which is independent of temperature over the range investigated. The extrapolated saturation magnetic moment is about 2.77 Bohr magnetons per ion.

  10. Photographic copy of plan of new Dy horizontal station and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photographic copy of plan of new Dy horizontal station and accumulator additions to Test Stand "D," also showing existing Dd test station. JPL drawing by VTN Consolidated, Inc. Engineers, Architects, Planners, 2301 Campus Drive, Irvine, California 92664: "Jet Propulsion Laboratory-Edwards Test Station, Motive Steam Supply & Ejector Pumping System: Plan - Test Stand "D," sheet M-3 (JPL sheet number E24/33), 21 December 1976 - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

  11. 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.

    PubMed

    Costes, Jean Pierre; Titos-Padilla, Silvia; Oyarzabal, Itziar; Gupta, Tulika; Duhayon, Carine; Rajaraman, Gopalan; Colacio, Enrique

    2016-05-01

    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

  12. Two-quasiparticle structures and isomers in {sup 168}Er, {sup 170}Er, and {sup 172}Er.

    SciTech Connect

    Dracoulis, G. D.; Lane, G. J.; Kondev, F. G.; Watanabe, H.; Seweryniak, D.; Zhu, S.; Carpenter, M. P.; Chiara, C. J.; Janssens, R. V. F.; Lauritsen, T.; Lister, C. J.; McCutchan, E. A.; Stefanescu, I.; Australian National Univ.; RIKEN; Univ. of Maryland

    2010-05-01

    The stable and neutron-rich isotopes 168Er, 170Er, and 172Er have been studied with Gammasphere using inelastic excitation with energetic 136Xe beams. The previously assigned structures based on the proposed K?=4- isomeric intrinsic states in both 168Er and 170Er have been re-evaluated and an equivalent band identified in 172Er. In 170Er, the identification of a K?=6- band with transitions close in energy to those of the 4- band leads to a modified interpretation, since the overlap would have compromised previous analyses. The gK-gR values for the 4- bands deduced from the in-band ?-ray intensities for the sequence of isotopes suggest a predominantly two-neutron configuration in 168Er, an equally mixed two-neutron, two-proton configuration in 170Er, and a two-proton configuration in 172Er. A comprehensive decay scheme for the previously proposed 6+ isomer in 172Er has also been established, as well as band structures built on this isomer that closely resemble the 6+ and 7- two-neutron structures known in the isotone 174Yb. The implied K hindrances are discussed. The main decay path of the 6+ isomer occurs through the newly identified 4- isomer. The measured lifetimes of the 4- and 6+ isomers in 172Er are 57(3) and 822(90) ns, respectively. Multiquasiparticle calculations support the suggested configuration changes across the isotopic chain.

  13. Synthesis of phase pure BiDyO3 and its structural characterization

    NASA Astrophysics Data System (ADS)

    Iyyapushpam, S.; Nishanthi, S. T.; Padiyan, D. Pathinettam

    2013-02-01

    Phase pure bismuth dysprosium oxide (BiDyO3) is prepared by means of a simple chemical route by varying calcining temperature. Its homogeneous nature is confirmed from XRD and the photocatalytic degradation exists only for the phase pure form of BiDyO3. The crystallite sizes of BiDyO3 calcined at 500, 600 and 700 °C are 9.9, 14.8 and 15.5 nm respectively and this confirms that the materials are in the form of nanocrystalline. For the phase pure BiDyO3 the degradation percentage is found to be 57% in 4 h.

  14. A structural and functional perspective of DyP-type peroxidase family.

    PubMed

    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. PMID:25655348

  15. Rational electrostatic design of easy-axis magnetic anisotropy in a Zn(II) -Dy(III) -Zn(II) single-molecule magnet with a high energy barrier.

    PubMed

    Oyarzabal, Itziar; Ruiz, José; Seco, José Manuel; Evangelisti, Marco; Camón, Agustín; Ruiz, Eliseo; Aravena, Daniel; Colacio, Enrique

    2014-10-27

    Two novel trinuclear complexes [ZnCl(μ-L)Ln(μ-L)ClZn][ZnCl3 (CH3 OH)]⋅3 CH3 OH (Ln(III) =Dy (1) and Er (2)) have been prepared from the compartmental ligand N,N'-dimethyl-N,N'-bis(2-hydroxy-3-formyl-5-bromo-benzyl)ethylenediamine (H2 L). X-ray studies reveal that Ln(III) ions are coordinated by two [ZnCl(L)](-) units through the phenoxo and aldehyde groups, giving rise to a LnO8 coordination sphere with square-antiprism geometry and strong easy-axis anisotropy of the ground state. Ab initio CASSCF+RASSI calculations carried out on 1 confirm that the ground state is an almost pure MJ =±15/2 Kramers doublet with a marked axial anisotropy, the magnetic moment is roughly collinear with the shortest DyO distances. This orientation of the local magnetic moment of the Dy(III) ion in 1 is adopted to reduce the electronic repulsion between the oblate electron shape of the MJ =±15/2 Kramers doublet and the phenoxo-oxygen donor atoms involved in the shortest DyO bonds. CASSCF+RASSI calculations also show that the ground and first excited states of the Dy(III) ion are separated by 129 cm(-1) . As expected for this large energy gap, compound 1 exhibits, in a zero direct-current field, thermally activated slow relaxation of the magnetization with a large Ueff =140 K. The isostructural Zn-Er-Zn species does not present significant SMM behavior as expected for the prolate electron-density distribution of the Er(III) ion leading to an easy-plane anisotropy of the ground doublet state. PMID:25251453

  16. Studies of sintered MRE-Fe-B magnets by DyF3 addition or diffusion treatment (MRE = Nd + Y + Dy)

    NASA Astrophysics Data System (ADS)

    Tang, W.; Dennis, K. W.; Kramer, M. J.; Anderson, I. E.; McCallum, R. W.

    2012-04-01

    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.

  17. Occurrence of magnetoelectric effect correlated to the Dy order in Dy2NiMnO6 double perovskite

    NASA Astrophysics Data System (ADS)

    Masud, Md G.; Dey, K.; Ghosh, A.; Majumdar, S.; Giri, S.

    2015-08-01

    Magnetic, dielectric, and ac conductivity as well as room temperature structural and Raman studies are performed on double perovskite Dy2NiMnO6. The crystal structure of the compound adopts monoclinic P21/n space group, where alternate Mn and Ni distorted octahedral are arranged in anti-phase a- a- b+ order in Glazer notation. Magnetization studies show two magnetic transitions around 100 K and 20 K which are related to the ordering of transition and rare earth cations moment, respectively. Temperature dependent dielectric permittivity shows Havriliak-Negami type thermally activated dielectric relaxation. The ac conductivity at different temperature is found to follow Jonscher power law behavior. Time-temperature scaling of the conductivity spectra reveals that the charge transport dynamics is independent of temperature. Intriguingly, an anomaly in the dielectric constant is observed close to the order of Dy moment which indicates intrinsic magnetoelectric coupling. The hybridization between Dy and Ni/Mn is suggested to be correlated with the magnetoelectric coupling.

  18. Characterization of Dye-decolorizing Peroxidase (DyP) from Thermomonospora curvata Reveals Unique Catalytic Properties of A-type DyPs.

    PubMed

    Chen, Chao; Shrestha, Ruben; Jia, Kaimin; Gao, Philip F; Geisbrecht, Brian V; Bossmann, Stefan H; Shi, Jishu; Li, Ping

    2015-09-18

    Dye-decolorizing peroxidases (DyPs) comprise a new family of heme peroxidases, which has received much attention due to their potential applications in lignin degradation. A new DyP from Thermomonospora curvata (TcDyP) was identified and characterized. Unlike other A-type enzymes, TcDyP is highly active toward a wide range of substrates including model lignin compounds, in which the catalytic efficiency with ABTS (kcat(app)/Km(app) = (1.7 × 10(7)) m(-1) s(-1)) is close to that of fungal DyPs. Stopped-flow spectroscopy was employed to elucidate the transient intermediates as well as the catalytic cycle involving wild-type (wt) and mutant TcDyPs. Although residues Asp(220) and Arg(327) are found necessary for compound I formation, His(312) is proposed to play roles in compound II reduction. Transient kinetics of hydroquinone (HQ) oxidation by wt-TcDyP showed that conversion of the compound II to resting state is a rate-limiting step, which will explain the contradictory observation made with the aspartate mutants of A-type DyPs. Moreover, replacement of His(312) and Arg(327) has significant effects on the oligomerization and redox potential (E°') of the enzyme. Both mutants were found to promote the formation of dimeric state and to shift E°' to a more negative potential. Not only do these results reveal the unique catalytic property of the A-type DyPs, but they will also facilitate the development of these enzymes as lignin degraders. PMID:26205819

  19. Neutron diffraction studies of RSn{sub 1+x}Ge{sub 1-x} (R=Tb-Er) compounds

    SciTech Connect

    Gil, A.; Hoser, A.; Szytula, A.

    2011-07-15

    The magnetic structures of RSn{sub 1+x}Ge{sub 1-x} (R=Tb, Dy, Ho and Er, x{approx}0.1) compounds have been determined by neutron diffraction studies on polycrystalline samples. The data recorded in a paramagnetic state confirmed the orthorhombic crystal structure described by the space group Cmcm. These compounds are antiferromagnets at low temperatures. The magnetic ordering in TbSn{sub 1.12}Ge{sub 0.88} is sine-modulated described by the propagation vector k=(0.4257(2), 0, 0.5880(3)). Tb magnetic moment equals 9.0(1) {mu}{sub B} at 1.62 K. It lies in the b-c plane and form an angle {theta}=17.4(2) deg. with the c-axis. This structure is stable up to the Neel temperature equal to 31 K. The magnetic structures of RSn{sub 1+x}Ge{sub 1-x}, where R are Dy, Ho and Er at low temperatures are described by the propagation vector k=(1/2, 1/2, 0) with the sequence (++-+) of magnetic moments in the crystal unit cell. In DySn{sub 1.09}Ge{sub 0.91} and HoSn{sub 1.1}Ge{sub 0.9} magnetic moments equal 7.25(15) and 8.60(6) {mu}{sub B} at 1.55 K, respectively. The moments are parallel to the c-axis. For Ho-compound this ordering is stable up to T{sub N}=10.7 K. For ErSn{sub 1.08}Ge{sub 0.92}, the Er magnetic moment equals 7.76(7) {mu}{sub B} at T=1.5 K and it is parallel to the b-axis. At T{sub t}=3.5 K it tunes into the modulated structure described by the k=(0.496(1), 0.446(4), 0). With the increase of temperature there is a slow decrease of k{sub x} component and a quick decrease of k{sub y} component. The Er magnetic moment is parallel to the b-axis up to 3.9 K while at 4 K and above it lies in the b-c plane and form an angle 48(3) deg. with the c-axis. In compounds with R=Tb, Ho and Er the magnetostriction effect at the Neel temperature is observed. - Graphical abstract: The magnetic structures of RSn{sub 1+x}Ge{sub 1-x} (R=Tb, Dy, Ho and Er, x{approx}0.1) compounds have been determined by neutron diffraction studies on polycrystalline samples. The magnetic ordering in Tb

  20. NASA ER-2: Flying Laboratory for Earth Science Studies

    NASA Technical Reports Server (NTRS)

    Navarro, Robert

    2007-01-01

    This viewgraph presentation gives an overview of the NASA ER-2 aircraft. The contents include: 1) ER-2 Specifications; 2) ER-2 Basic Configuration; 3) ER-2 Payload Areas: Nose Area; 4) ER-2 Payload Areas: SuperPod Fore and Aftbody; 5) ER-2 Payload Areas: SuperPod Midbody; 6) ER-2 Payload Areas: Q-Bay; 7) ER-2 Payload Areas: Q-Bay Hatch Designs; 8) ER-2 Payload Areas: External Pods; 9) ER-2 Electrical/Control Interface; 10) ER-2 Typical Flight Profile; 11) Tropical Composition, Cloud and Climate Coupling TC-4; 12) TC-4 Timeline; 13) TC4 Area of Interest; 14) ER-2 TC4 Payload; 15) A/C ready for fuel; 16) ER-2 Pilot being suited; 17) ER-2 Taxing; 18) ER-2 Pilot post flight debrief; and 19) NASA ER-2: Flying Laboratory for Earth Science Studies and Remote Sensing.

  1. The hydrogenation of Dy{sub 5}Pd{sub 2} followed by in situ methods

    SciTech Connect

    Kohlmann, H.; Talik, E.; Hansen, T.C.

    2012-03-15

    The hydrogenation behavior of the intermetallic compound Dy{sub 5}Pd{sub 2} was investigated by means of ex situ X-ray powder diffraction, in situ neutron powder diffraction and in situ differential scanning calorimetry. The structural model of Dy{sub 5}Pd{sub 2} with a palladium atom at the 32(e) position x, x, x (x Almost-Equal-To 0.22, 7/8 occupation) and a dysprosium atom at almost the same location (x Almost-Equal-To 0.18, 1/8 occupation) is confirmed. Upon heating the latter approaches x(Pd) and at T=399 K both positional parameters are indistinguishable. Dy{sub 5}Pd{sub 2} does not incorporate hydrogen (deuterium) into its crystal structure, however, starting at T=495 K reacts with hydrogen to non stoichiometric dysprosium dideuteride, DyD{sub 2+x}, following a parabolic rate law. In situ differential scanning calorimetry at various hydrogen pressures up to 2.5 MPa shows strongly exothermic signals, whose temperature onset depend on the gas pressure, corresponding to the formation of a mainly ionic hydride (DyH{sub 2+x}). - Graphical abstract: The hydrogenation of Dy5Pd2 is being followed by in situ neutron diffraction. Highlights: Black-Right-Pointing-Pointer Dy5Pd2 does not form a ternary hydride upon hydrogenation. Black-Right-Pointing-Pointer Dy5Pd2 decomposes to binary hydrides of dysprosium and palladium. Black-Right-Pointing-Pointer At T{>=}399 K Dy3 and Pd in the crystal structure of Dy5Pd2 share the same position. Black-Right-Pointing-Pointer The formation of DyD2+x at T=495 K and p(D2)=2.5 MPa follows a parabolic rate law.

  2. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics.

    PubMed

    Bravo, Roberto; Gutierrez, Tomás; Paredes, Felipe; Gatica, Damián; Rodriguez, Andrea E; Pedrozo, Zully; Chiong, Mario; Parra, Valentina; Quest, Andrew F G; Rothermel, Beverly A; Lavandero, Sergio

    2012-01-01

    Endoplasmic reticulum (ER) stress activates an adaptive unfolded protein response (UPR) that facilitates cellular repair, however, under prolonged ER stress, the UPR can ultimately trigger apoptosis thereby terminating damaged cells. The molecular mechanisms responsible for execution of the cell death program are relatively well characterized, but the metabolic events taking place during the adaptive phase of ER stress remain largely undefined. Here we discuss emerging evidence regarding the metabolic changes that occur during the onset of ER stress and how ER influences mitochondrial function through mechanisms involving calcium transfer, thereby facilitating cellular adaptation. Finally, we highlight how dysregulation of ER-mitochondrial calcium homeostasis during prolonged ER stress is emerging as a novel mechanism implicated in the onset of metabolic disorders. PMID:22064245

  3. X-ray resonant magnetic scattering investigations of hexagonal multiferroics RMnO3 (R = Dy, Ho, Er)

    SciTech Connect

    Nandi, Shibabrata

    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.

  4. First-principles study of rare-earth (RE) cobaltites (RE=Nd,Sm,Gd,Dy,Er,Lu)

    NASA Astrophysics Data System (ADS)

    Topsakal, M.; Wentzcovitch, R. M.

    2014-12-01

    The lanthanide series of the periodic table comprises 15 members ranging from Lanthanum (La) to Lutetium (Lu). Although they are more abundant than silver, and some of them are more abundant than lead, they are known as rare-earth (RE) elements. The "rare" in their name refers to the difficulty of obtaining the pure elements, not to their abundances in nature. They are never found as free metals in the Earth's crust and do not exist as pure minerals. Using first-principles plane-wave calculations, we investigate the structural and electronic properties of rare-earth cobaltites (RECoO3). Structurally consistent Hubbard U treatment was shown to essential for proper description of strongly correlated cobalt-d electrons. We successfully capture the experimentally observed structural trends and give first-principles insights on interesting phenomena related with the cobalt spin state change. It was demonstrated that increase of crystal-field splitting energy between eg-t2g orbitals and shrinking of unoccupied σ*-bonding eg bands are responsible for the increase of onset spin-state transition temperature along the series.

  5. Coercivity enhancement of Nd-Fe-B thin film magnets by Dy buffer and capping layers

    NASA Astrophysics Data System (ADS)

    You, C. Y.; Wang, J. W.; Lu, Z. X.

    2012-04-01

    The Dy layer was inserted into the structure of SiO2/Ti/Nd-Fe-B/Ti as the buffer or capping layer of the Nd-Fe-B layer. The insertions of Dy layers had no significant influence on the film texture with the easy axis mainly perpendicular to the film plane. The film without Dy layer gave the out-of-plane coercivity of 533 kA/m, maximum magnetic energy product (BH)max of 245 kJ/m3. With a Dy buffer layer, the out-of-plane coercivity and (BH)max were increased to 1074 kA/m, 291 kJ/m3 respectively. The film with Dy capping layer had a coercivity of 1035 kA/m and (BH)max of 286 kJ/m3. Microstructure observations showed that the Nd-rich phases were evolved into grain boundaries from triple junctions by a Dy buffer layer deposition, resulting in a well magnetic decoupling of Nd2Fe14B neighboring grains. Through capping a Dy layer, the environment of grain boundaries had been improved and some Dy diffused into Nd2Fe14B phases, which contributed to the enhancement of magnetic performance.

  6. Field evaluation of a dyed food marking technique for Culex quinquefasciatus (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method of marking adult Cx. quinquefasciatus Say by feeding the larvae commercial hog chow dyed with methylene blue, Giemsa, and crystal violet was evaluated under field conditions. Larvae were offered the dyed food in outdoor basins containg a mixture of dairy effluent and fresh water. Newly emer...

  7. 26 CFR 48.4082-1 - Diesel fuel and kerosene; exemption for dyed fuel.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 16 2013-04-01 2013-04-01 false Diesel fuel and kerosene; exemption for dyed..., Tread Rubber, and Taxable Fuel Taxable Fuel § 48.4082-1 Diesel fuel and kerosene; exemption for dyed... kerosene satisfies the dyeing and marking requirements of paragraphs (b), (c), and (d) of this section....

  8. 26 CFR 48.4082-1T - Diesel fuel and kerosene; exemption for dyed fuel (temporary).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 16 2012-04-01 2012-04-01 false Diesel fuel and kerosene; exemption for dyed...; exemption for dyed fuel (temporary). (a) through (c) . For further guidance, see § 48.4082-1(a) through (c). (d) Time and method for adding dye—(1) In general. Except as provided by paragraph (d)(6) of...

  9. 26 CFR 48.4082-1 - Diesel fuel and kerosene; exemption for dyed fuel.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 16 2011-04-01 2011-04-01 false Diesel fuel and kerosene; exemption for dyed..., Tread Rubber, and Taxable Fuel Taxable Fuel § 48.4082-1 Diesel fuel and kerosene; exemption for dyed... kerosene satisfies the dyeing and marking requirements of paragraphs (b), (c), and (d) of this section....

  10. 26 CFR 48.4082-1T - Diesel fuel and kerosene; exemption for dyed fuel (temporary).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 16 2011-04-01 2011-04-01 false Diesel fuel and kerosene; exemption for dyed...; exemption for dyed fuel (temporary). (a) through (c) . For further guidance, see § 48.4082-1(a) through (c). (d) Time and method for adding dye—(1) In general. Except as provided by paragraph (d)(6) of...

  11. 26 CFR 48.4082-1 - Diesel fuel and kerosene; exemption for dyed fuel.

    Code of Federal Regulations, 2010 CFR

    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... kerosene satisfies the dyeing and marking requirements of paragraphs (b), (c), and (d) of this section....

  12. 26 CFR 48.4082-1 - Diesel fuel and kerosene; exemption for dyed fuel.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 16 2012-04-01 2012-04-01 false Diesel fuel and kerosene; exemption for dyed..., Tread Rubber, and Taxable Fuel Taxable Fuel § 48.4082-1 Diesel fuel and kerosene; exemption for dyed... kerosene satisfies the dyeing and marking requirements of paragraphs (b), (c), and (d) of this section....

  13. 26 CFR 48.4082-1T - Diesel fuel and kerosene; exemption for dyed fuel (temporary).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Diesel fuel and kerosene; exemption for dyed...; exemption for dyed fuel (temporary). (a) through (c) . For further guidance, see § 48.4082-1(a) through (c). (d) Time and method for adding dye—(1) In general. Except as provided by paragraph (d)(6) of...

  14. 26 CFR 48.4082-1T - Diesel fuel and kerosene; exemption for dyed fuel (temporary).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 16 2013-04-01 2013-04-01 false Diesel fuel and kerosene; exemption for dyed...; exemption for dyed fuel (temporary). (a) through (c) . For further guidance, see § 48.4082-1(a) through (c). (d) Time and method for adding dye—(1) In general. Except as provided by paragraph (d)(6) of...

  15. Erratum: Radiative strength functions in Dy163,164 [Phys. Rev. C 81, 024325 (2010)

    NASA Astrophysics Data System (ADS)

    Nyhus, H. T.; Siem, S.; Guttormsen, M.; Larsen, A. C.; Bürger, A.; Syed, N. U. H.; Tveten, G. M.; Voinov, A.

    2010-08-01

    The nuclei 163,164Dy have been investigated using the Oslo method on data from the pick-up reaction 164Dy(3He,alpha gamma)163Dy and the inelastic scattering 164Dy(3He,3He' gamma)164Dy, respectively. The radiative strength functions for both nuclei have been extracted, and a small resonance centered around Eg ?3 MeV is observed in both cases. The parameters of this so-called pygmy M1 resonance (the scissors mode) are compared to previous results on 160,161,162Dy using the Oslo method, and to data on 163Dy measured by the Prague group using the two-step cascade method. In particular, the integrated reduced transition probability B(M1) of the pygmy resonance is compared with neighboring dysprosium isotopes. We also observe an enhanced strength in the region above gamma energy around 5 MeV in 164Dy. Possible origins of this feature are discussed.

  16. Quadrupole moments in chiral material DyFe3(BO3)4 observed by resonant x-ray diffraction

    NASA Astrophysics Data System (ADS)

    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.

  17. Faraday effect improvement by Dy3+-doping of terbium gallium garnet single crystal

    NASA Astrophysics Data System (ADS)

    Chen, Zhe; Yang, Lei; Hang, Yin; Wang, Xiangyong

    2016-01-01

    Highly transparent Dy3+-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 Dy3+ in the crystal was obtained. The optical and magneto-optical properties were analyzed in detail, and magnetic properties of the Dy3+-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 Dy3+-doped TGG, as compared to the properties of pure TGG, indicating that Dy3+-doped crystals are preferable for magneto-active materials used in Faraday devices at VIS-NIR wavelengths.

  18. Photoluminescence and thermoluminescence studies of CaAl2O4:Dy(3+) phosphor.

    PubMed

    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. PMID:25920456

  19. Giant magnetocaloric effect in antiferromagnetic DyVO4 compound

    NASA Astrophysics Data System (ADS)

    Midya, A.; Khan, N.; Bhoi, D.; Mandal, P.

    2014-09-01

    We have investigated the magnetic and magnetocaloric properties of DyVO4 by magnetization and heat capacity measurements. χ(T) shows antiferromagnetic to paramagnetic transition at TNDy~3.5 K. The compound undergoes a metamagnetic transition and exhibits a huge entropy change. The maximum values of magnetic entropy change (ΔSM), adiabatic temperature change (ΔTad) and refrigerant capacity (RC) reach 26 J kg-1 K-1, 17 K, and 526 J kg-1, respectively for a field change of 0-8 T. Moreover, the material is highly insulating and exhibits no thermal and field hysteresis, satisfying the necessary conditions for a good magnetic refrigerant material.

  20. On the change of period of Dy Pegasi

    NASA Astrophysics Data System (ADS)

    Jiang, Shi-yang; Zhao, Nan-sheng

    1982-06-01

    In the course of testing a 3-channel photon-counting, high-speed photometer, we observed DY Peg on three nights, 1980 September 18, 19, and November 15, and obtained 7 light maxima. Combining with results observed over the past 30 years, we re-calculated the formula for the maximum epoch to be T max = H.J.D.2432751.96182 + 0.072926362 E - 2.28 × 10 -13E2± 0.00008 ± 0.000000001 ± 0.09 and the period decay rate to be (3.1± 0.1) × 10 -8yr -1.

  1. Anisotropic elasticity of DyScO3 substrates

    NASA Astrophysics Data System (ADS)

    Janovská, Michaela; Sedlák, Petr; Seiner, Hanuš; Landa, Michal; Marton, Pavel; Ondrejkovič, Petr; Hlinka, Jiří

    2012-09-01

    The full elastic tensor of orthorhombic dysprosium scandate (DyScO3) at room temperature was determined by resonant ultrasound spectroscopy (RUS). Measurements were performed on three 500 μm thick substrates with orientations (110), (100) and (001) in the Pbnm (a < b < c) setting. For this purpose, a modification of the RUS method was developed, enabling simultaneous processing of the resonant spectra of several platelet-shaped samples with different crystallographic orientations. The obtained results are compared with ab initio calculations and with elastic constants of other rare-earth scandates, and are used for discussion of the in-plane elasticity of the (110)-oriented substrate.

  2. Phase Transitions above the Yrast Line in {sup 154}Dy

    SciTech Connect

    Ma, W. C.; Martin, V.; Khoo, T. L.; Lauritsen, T.; Egido, J. L.; Ahmad, I.; Bhattacharyya, P.; Carpenter, M. P.; Daly, P. J.; Grabowski, Z. W.

    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.

  3. Parametric models of reflectance spectra for dyed fabrics

    NASA Astrophysics Data System (ADS)

    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.

  4. Electronic state of Er in sputtered AlN:Er films determined by magnetic measurements

    SciTech Connect

    Narang, V.; Seehra, M. S.; Korakakis, D.

    2014-12-07

    The optoelectronic and piezoelectric properties of AlN:Er thin films have been of great recent interest for potential device applications. In this work, the focus is on the electronic state of Er in AlN:Er thin films prepared by reactive magnetron sputtering on (001) p-type Si substrate. X-ray diffraction shows that Er doping expands the lattice and the AlN:Er film has preferential c-plane orientation. To determine whether Er in AlN:Er is present as Er metal, Er{sub 2}O{sub 3}, or Er{sup 3+} substituting for Al{sup 3+}, detailed measurements and analysis of the temperature dependence (2 K–300 K) of the magnetization M at a fixed magnetic field H along with the M vs. H data at 2 K up to H = 90 kOe are presented. The presence of Er{sub 2}O{sub 3} and Er metal is ruled out since their characteristic magnetic transitions are not observed in the AlN:Er sample. Instead, the observed M vs. T and M vs. H variations are consistent with Er present as Er{sup 3+} substituting for Al{sup 3+} in AlN:Er at a concentration x = 1.08% in agreement with x = 0.94% ± 0.20% determined using x-ray photoelectron spectroscopy (XPS). The larger size of Er{sup 3+} vs. Al{sup 3+}explains the observed lattice expansion of AlN:Er.

  5. First heterometallic Ga(III)-Dy(III) single-molecule magnets: implication of Ga(III) in extracting Fe-Dy interaction.

    PubMed

    Chen, Sihuai; Mereacre, Valeriu; Anson, Christopher E; Powell, Annie K

    2016-05-31

    The compounds of the system [M4M'2(μ3-OH)2(nbdea)4(C6H5CO2)8]·MeCN, where M = Ga(III), M' = Dy(III) (), M = Fe(III), M' = Y(III) () are isostructural to the known [Fe4Dy2] compound (). Those of the system [M4M'4(μ3-OH)4(nbdea)4(m-CH3C6H4CO2)12]·nMeCN, where M = Ga(III), M' = Dy(III), n = 4 (), M = Fe(III), M' = Y(III), n = 1 () are isostructural to the [Fe4Dy4] compound (). This allows for comparisons between single ion effects of the paramagnetic ions. The structures were determined using single crystal analysis. Magnetic susceptibility measurements reveal that the Ga(III)-Dy(III) compounds and are SMMs. The energy barrier for is close to that for the known isostructural Fe4Dy2 compound (), but with a significantly increased relaxation time. PMID:27184869

  6. Analysis of the spectrum of Dy/sup 3 +/:LaF/sub 3/ assuming a C/sub2v/ site summetry

    SciTech Connect

    Goodman, G.L.; Carnall, W.T.; Rana, R.S.; Vandevelde, P.; Fluyt, L.; Goerller-Walrand, C.

    1986-06-01

    Previous successful analyses of the observed crystal-field structure in Tm/sup 3 +/:LaF/sub 3/ and Ho/sup 3 +/:LaF/sub 3/ in an approximate C/sub 2v/ site symmetry have depended upon a crystal-field model derived in an analysis of the spectrum of Er/sup 3 +/:LaF/sub 3/. The present investigation compares the predictions of this same model to the observed crystal-field structure in Dy/sup 3 +/:LaF/sub 3/. The energy parameters resulting from a least-square fit of the corresponding spectral assignments are reported. To help clarify the physical situation, some comparisions are offered between C/sub 2v/ and D/sub 3h/ crystal-field models for these Ln/sup 3 +/:LaF/sub 3/ systems. 7 refs., 3 figs., 2 tabs.

  7. UBV photometry of ER Vulpeculae

    NASA Astrophysics Data System (ADS)

    Srivastava, R. K.; Padalia, T. D.; Srivastava, J. B.

    1991-08-01

    UBV photometry of the RS CVn-type eclipsing binary system ER Vulpeculae has been presented. The period comes out to be 0.698093d. The average depths of primary and secondary minima are, respectively, 0.21 and 0.12m. The colors at various phases have been given. A dip is seen around phase 0.73P as was seen in the observations of Arevalo et al. (1988). Large scatter is present in the observations as noticed earlier, and may be due to activity of the components.

  8. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics

    PubMed Central

    Bravo, Roberto; Gutierrez, Tomás; Paredes, Felipe; Gatica, Damián; Rodriguez, Andrea E.; Pedrozo, Zully; Chiong, Mario; Parra, Valentina; Quest, Andrew F.G.; Rothermel, Beverly A.; Lavandero, Sergio

    2014-01-01

    Endoplasmic reticulum (ER) stress activates an adaptive unfolded protein response (UPR) that facilitates cellular repair, however, under prolonged ER stress, the UPR can ultimately trigger apoptosis thereby terminating damaged cells. The molecular mechanisms responsible for execution of the cell death program are relatively well characterized, but the metabolic events taking place during the adaptive phase of ER stress remain largely undefined. Here we discuss emerging evidence regarding the metabolic changes that occur during the onset of ER stress and how ER influences mitochondrial function through mechanisms involving calcium transfer, thereby facilitating cellular adaptation. Finally, we highlight how dysregulation of ER–mitochondrial calcium homeostasis during prolonged ER stress is emerging as a novel mechanism implicated in the onset of metabolic disorders. PMID:22064245

  9. Shape Coexistence and Band Terminations in N = 89 ^155Dy

    NASA Astrophysics Data System (ADS)

    Brown, T. B.; Riley, M. A.; Janssens, R. V. F.; Ahmad, I.; Blumenthal, D. J.; Carpenter, M. P.; Fallon, P.; Fischer, S. M.; Hackman, G.; Hartley, D. J.; Kalfas, C.; Khoo, T. L.; Kondev, F. G.; Lauritsen, T.; Nisius, D.; Ma, W. C.; Simpson, J.; Sharpey-Schafer, J. F.; Afanasiev, A.; Ragnarsson, I.

    1998-04-01

    A high spin study of the nucleus ^155_66Dy_89 has been performed using the GAMMASPHERE Spectrometer. The ^124Sn(^36S,5n) reaction was employed at beam energies of 175 and 165 MeV with thick and thin targets respectively. Eight new band sequences have been identified and the previously known sequences have been extended to higher spin. The yrast states of positive and negative parity have been identified up to spin 1/012 with quite different behavior illustrating beautifully the competition between collective prolate and terminating oblate shapes. Detailed comparisions are made with cranked Nilsson Strutinsky calculations. A new feature of the high spin calculations has been added to distinguish between neutrons in h_11/2 orbitals and other N=5 orbitals. This has been found necessary to explain the continuation of near yrast collective structures beyond spin 40 hbar. Additionally, the lowest energy negative parity sequences are observed to return to more collective behavior near spin 45 in a similar manner as N=88 ^154Dy.

  10. White light generation from Dy3+ doped tellurite glass

    NASA Astrophysics Data System (ADS)

    Damak, Kamel; Yousef, El Sayed; Rüssel, Christian; Maâlej, Ramzi

    2014-02-01

    This paper reports on the spectral results of Dy3+ (1.0 mol%) ions-doped TeO2-ZnO-PbO-PbF2-Na2O (TZPPN) glass. Raman spectrum measurements, differential thermal analysis (DTA) profiles of this rare-earth ion-doped glass were carried out. From the DTA thermogram, glass transition (Tg), crystallization (Tc) and melting (Tm) temperatures were evaluated. Direct and indirect optical band gaps were calculated based on the glasses UV absorption spectra. From the absorption spectra, Judd-Ofelt (J-O) intensity parameters, Ωk, were calculated. Using J-O intensity parameters, several radiative properties such as spontaneous transition probabilities (AR), radiative branching ratios (βR) and radiative lifetimes (τR) were determined for the excitation level 4F9/2. From the emission spectra, a strong yellow emission at 574 nm (4F9/2→6H13/2) was observed and it also showed a combination of blue and red emission bands for this glass. The stimulated emission cross-section σ(λp) was also evaluated for the 4F9/2→6HJ (J=11/2, 13/2, and 15/2) transitions. This study indicates that 1 mol% Dy2O3-doped tellurite glass can be considered for white light generation with the excitation of blue light (454 nm).

  11. Magnetic dipole excitations of the 163Dy nucleus

    NASA Astrophysics Data System (ADS)

    Zenginerler, Zemine; Tabar, Emre; Yakut, Hakan; Kuliev, Ali Akbar; Guliyev, Ekber

    2014-03-01

    In this study some properties of the magnetic dipole excitations of the deformed odd mass 163Dy nucleus were studied by using Quasiparticle-phonon nuclear model (QPNM). The several of the ground-state and low-lying magnetic dipole (M1) mode characteristics were calculated for deformed odd-mass nuclei using a separable Hamiltonian within the QPNM. The M1 excited states, reduced transition probabilities B(M1), the ground-state magnetic properties such as magnetic moment (μ), intrinsic magnetic moment (gK) , effective spin factor (gseff.) are the fundamental characteristics of the odd-mass nucleus and provide key information to understand nuclear structure. The theoretical results were compared with the available experimental data and other theoretical approaches. Calculations show that the spin-spin interaction in this isotopes leads to polarization effect influencing the magnetic moments. Furthermore we found a strong fragmentation of the M1 strength in 163Dy nucleus which was in qualitative agreement with the experimental data. Sakarya University, Project Number: 2012-50-02-007 and Z.Zenginerler acknowledge to TUBITAK-TURKEY 2013, fellowship No: 2219.

  12. Coercivity enhancement of Nd-Fe-B sintered magnets with intergranular adding (Pr, Dy, Cu)-Hx powders

    NASA Astrophysics Data System (ADS)

    Zhang, Yujing; Ma, Tianyu; Liu, Xiaolian; Liu, Pan; Jin, Jiaying; Zou, Junding; Yan, Mi

    2016-02-01

    Forming Nd2Fe14B/(Nd, Dy)2Fe14B core-shell structure by intergranular adding Dy-containing sources into Nd-Fe-B sintered magnets is effective to improve coercivity and to minimize remanence loss simultaneously. However, the excessive Dy located in the intergranular regions has nearly no hard magnetic contribution, causing its low utilization efficiency. In this work, diluted Dy powders (Pr37Dy30Cu33)-Hx were prepared and incorporated into Nd-Fe-B sintered magnets via a dual-alloy approach. The coercivity increases rapidly from 15.0 to 18.2 kOe by 21.3% with 2.0 wt% (Pr, Dy, Cu)-Hx addition (the equivalent Dy is only 0.32 at%). The deduced coercivity incremental ratio is 10.0 kOe per unit Dy at%. Dehydrogenation reaction of (Pr, Dy, Cu)-Hx occurs during sintering, which favors Dy diffusion towards the 2:14:1 phase grains as well as smoothing the grain boundaries (GBs). The enhanced local anisotropic field and the well decoupled 2:14:1 phase grains contribute to such rapid coercivity enhancement. This work suggests that adding diluted Dy hydrides is promising for fabricating high coercivity Nd-Fe-B sintered magnets with less heavy rare-earth consumption.

  13. Luminescence and Thermal Properties of Er:GSGG and Yb,Er:GSGG Laser Crystals

    NASA Astrophysics Data System (ADS)

    Sun, Dun-Lu; Luo, Jian-Qiao; Xiao, Jing-Zhong; Zhang, Qing-Li; Chen, Jia-Kang; Liu, Wen-Peng; Kang, Hong-Xiang; Yin, Shao-Tang

    2012-05-01

    Er3+-doped and Yb3+/Er3+ co-doped Gd3Sc2Ga3O12 (abbreviated as Er:GSGG and Yb,Er:GSGG, respectively) laser crystals are investigated by using a combination of spectroscopic measurements and thermal characterizations. An absorption peak of Yb,Er:GSGG crystal shifts to 970 nm and its absorption band broadens obviously, which makes the crystal suitable for pumping by a 970 nm laser diode (LD). This crystal also exhibits a shorter lifetime of a lower laser level, a larger emission cross section and higher thermal conductivity than those of Er:GSGG. All these factors suggest that Yb3+/Er3+ co-doping has a positive effect on improving the spectroscopic and thermal performances in GSGG based laser crystals, and imply that double-doped Yb,Er:GSGG crystal is a potential candidate as an excellent LD pumped 2.79 μm laser material.

  14. Thermoluminescence dosimetry features of DY and Cu doped SrF2 nanoparticles under gamma irradiation.

    PubMed

    Zahedifar, M; Sadeghi, E; Kashefi biroon, M; Harooni, S; Almasifard, F

    2015-11-01

    Dy and Cu-doped SrF2 nanoparticles (NPs) were synthesized by using co-precipitation method and their possible application to solid state dosimetry were studied and compared to that of pure SrF2 NPs. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) were used for sample characterization. The highest thermoluminescence (TL) response of SrF2:Dy and SrF2:Cu NPs were found respectively at 0.5 and 0.7mol% of Dy and Cu impurities. Seven overlapping glow peaks at 384, 406, 421, 449, 569, 495, 508K and three component glow peaks at 381, 421 and 467K were identified respectively for SrF2:Dy and SrF2:Cu NPs employing Tm-Tstop and computerized glow curve deconvolution (CGCD) methods. The TL sensitivity of SrF2:Dy is approximately the same as that of LiF:Mg,Ti (TLD-100) cheeps. Linear dose response were observed for the SrF2:Dy and SrF2:Cu NPs up to the absorbed doses of 1kGy and 10kGy correspondingly. Regarding other dosimetry characteristics of the produced NPs such as fading, reproducibility and thermal treatment, Dy and Cu doped SrF2 NPs recommend for high dose TL dosimetry applications. PMID:26319090

  15. Study of Dy-doped Bi2Te3: thin film growth and magnetic properties

    NASA Astrophysics Data System (ADS)

    Harrison, S. E.; Collins-McIntyre, L. J.; Zhang, S.-L.; Baker, A. A.; Figueroa, A. I.; Kellock, A. J.; Pushp, A.; Parkin, S. S. P.; Harris, J. S.; van der Laan, G.; Hesjedal, T.

    2015-06-01

    Breaking the time-reversal symmetry (TRS) in topological insulators (TIs) through ferromagnetic doping is an essential prerequisite for unlocking novel physical phenomena and exploring potential device applications. Here, we report the successful growth of high-quality (DyxBi1-x)2Te3 thin films with Dy concentrations up to x = 0.355 by molecular beam epitaxy. Bulk-sensitive magnetisation studies using superconducting quantum interference device magnetometry find paramagnetic behaviour down to 2 K for the entire doping series. The effective magnetic moment, μeff, is strongly doping concentration-dependent and reduces from ˜12.6 μB Dy-1 for x = 0.023 to ˜4.3 μB Dy-1 for x = 0.355. X-ray absorption spectra and x-ray magnetic circular dichroism (XMCD) at the Dy M4,5 edge are employed to provide a deeper insight into the magnetic nature of the Dy3+-doped films. XMCD, measured in surface-sensitive total-electron-yield detection, gives μeff = 4.2 μB Dy-1. The large measured moments make Dy-doped films interesting TI systems in which the TRS may be broken via the proximity effect due to an adjacent ferromagnetic insulator.

  16. Green synthesis of Y2O3:Dy(3+) nanophosphor with enhanced photocatalytic activity.

    PubMed

    Prasanna Kumar, J B; Ramgopal, G; Vidya, Y S; Anantharaju, K S; Daruka Prasad, B; Sharma, S C; Prashantha, S C; Nagaswarupa, H P; Kavyashree, D; Nagabhushana, H

    2015-10-01

    Facile and green route was employed for the synthesis of Y2O3:Dy(3+) (1-11 mol%) nanostructures (NSs) using Aloe vera gel as fuel. The formation of different morphologies of Y2O3:Dy(3+) NSs were characterized by SEM, TEM and HRTEM. PXRD data and Rietveld analysis evident the formation of single phase Y2O3 with cubic crystal structure. The influence of Dy(3+) ion concentration on the structure morphology, UV absorption, PL emission and photocatalytic activity of NSs were investigated. NSs exhibited an intense warm white emission with CIE chromaticity coordinates (0.32, 0.33) and average CCT value ∼5525 K which corresponds to vertical day light. The control of Dy(3+) ion on Y2O3 matrix influences the photocatalytic decolorization of Metanil Yellow as a model compound was evaluated. The enhanced photocatalytic activities of core shell structured Y2O3:Dy(3+) (1 mol%) was attributed to co-operation effect of dopant concentration, crystallite size, textural properties and capability for reducing electron-hole pair recombination. Further, the recycling catalytic ability of Y2O3:Dy(3+) (1 mol%) nanostructure was also evaluated and found promising photocatalytic performance with negligible decrease in decolorization efficiency even after sixth successive cyclic runs. Considering its green, facile synthesis and recyclable feature from an aqueous solution, the present Y2O3:Dy(3+) (1 mol%) nanophosphor can be considered as one of the ideal photocatalyst for various potential applications. PMID:25985135

  17. Decay of {sup 161m1,m2}Dy isomers under conditions of a resonance environment (Moessbauer Screen)

    SciTech Connect

    Loginov, Yu. E. Zinoviev, V. G.; Kabina, L. P.; Lisin, S. S.; Maljutenkov, Ed. I.

    2013-06-15

    The half-lives of the isomers {sup 161m1}Dy and {sup 161m2}Dy (E = 25.6 keV and T{sub 1/2} {approx} 30 ns for the former and E = 74.6 keV and T{sub 1/2} {approx} 3 ns for the latter) placed in a {sup 160}Gd{sub 2}O{sub 3} crystal lattice at T = 300 K and surrounded by stable {sup 161}Dy nuclei in the composition of {sup 161}Dy{sub 2}O{sub 3} were measured by the method of ({beta}-{gamma}) coincidences in the beta-decay process {sup 161}Tb {yields} {sup 161}Dy. Nuclei of {sup 161m1,m2}Dy were obtained according to the chain {sup 160}Gd(n, {gamma}){sup 161}Gd {yields} {sup 161}Tb {yields} {sup 161}Dy from {sup 160}Dy{sub 2}O{sub 3} weighted portions irradiated at the PWR-M reactor of the Petersburg Nuclear Physics Institute (PNPI, Gatchina, Russia). The T{sub 1/2} value observed for the isomer {sup 161m1}Dy was found to be correlated with the number of surrounding {sup 161}Dy nuclei. The presence of this correlation in {sup 161m1}Dy can be explained by the multiple resonance scattering of photons from isomer decay within the sample used. No such correlation was observed for {sup 161m2}Dy. The half-lives measured for the isomers {sup 161m1}Dy and {sup 161m2}Dy in the absence of the above environment are 29.2(1) and 3.50(1) ns, respectively.

  18. Studies of sintered MRE-Fe-B magnets by DyF3 addition or diffusion treatment (MRE = Nd + Y + Dy)

    SciTech Connect

    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.

  19. Host dependence of spectroscopic properties of Dy 3+ - doped and Dy 3+, Tm 3+ -codped Ge-Ga-S-CdI 2 chalcohalide glasses.

    PubMed

    Guo, Haitao; Liu, Lei; Wang, Yongqian; Hou, Chaoqi; Li, Weinan; Lu, Min; Zou, Kuaisheng; Peng, Bo

    2009-08-17

    Two serial Dy(3+)-doped and Dy(3+), Tm(3+)-codoped (100-x)(0.8GeS(2).0.2Ga(2)S(3)).xCdI(2) (0Dy(3+)-doped glasses, increase of CdI(2) had positive effect up to 1330 nm fluorescence and the emission cross section (sigma emi) was estimated to be 4.19 x 10(-20)cm(2) for the 0.2 wt% Dy(3+)-doped 64 GeS(2).16 Ga(2)S(3).20 CdI(2) glass. In the Dy(3+), Tm(3+)-codoped glasses, increase of CdI(2) diminished the amount of ethane-like units [S(3)(Ga)Ge-Ge(Ga)S(3)], improved the Tm(3+): 3F 4-->Dy(3+): 6H 11/2 energy transfer efficiency and intensified the mid-infrared emissions. The emission cross sections (sigma emi) of the 2900 and 4300 nm fluorescences were estimated to be 1.68 x 10(-20) and 1.20 x 10(-20)cm(2) respectively for the 0.2 wt% Dy(3+) and 0.5 wt% Tm(3+) codoped 64 GeS(2).16 Ga(2)S(3).20 CdI(2) glass. These novel chalcohalide glasses are promising candidate materials for fiber-amplifiers and mid-infrared laser devices. PMID:19688013

  20. Development of YAG:Dy Thermographic Phosphor Coatings for Turbine Engine Applications

    NASA Technical Reports Server (NTRS)

    Eldridge, J. I.; Jenkins, T. P.; Allison, S. W.; Wolfe, D. E.; Jordan, E. H.

    2012-01-01

    The selection and development of thermographic phosphor coatings were pursued to meet the objective of demonstrating luminescence-decay-based temperature measurements up to 1300C on the surface of a vane in an operating demonstrator turbine engine. To meet this objective, YAG:Dy was selected based on the desirable luminescence performance observed for YAG:Dy powder: (1) excellent temperature sensitivity and intensity at operating turbine engine temperatures, (2) an emission peak at the relatively short wavelength of 456 nm, where the interference from background blackbody radiation is fairly low, and (3) its nearly single exponential decay which makes for a simple, reliable temperature calibration. However, implementation of YAG:Dy for surface temperature measurements required application of YAG:Dy as a coating onto the surface of a superalloy component with a preexisting yttria-stabilized zirconia (YSZ) thermal barrier coating (TBC). An inherent dilemma in producing a YAG:Dy coating is that coating processing is constrained to be performed at temperatures below (less than 1200C) what is considered safe for the superalloy component, much lower than temperatures used to produce the high quality crystalline powder. Therefore, YAG:Dy coatings tend to exhibit lower luminescence performance compared to well prepared YAG:Dy powder, and the luminescence performance of the coating will depend on the method of coating deposition. In this presentation, the luminescence performance of YAG:Dy coatings prepared by the different methods of (1) application of a binder-based YAG:Dy-containing paint, (2) solution precursor plasma spray (SPPS), and (3) electron-beam physical vapor deposition (EB-PVD) and the effect of post-deposition heat treatments will be discussed.

  1. Enneanuclear [Ni6Ln3] Cages: [Ln(III)3] Triangles Capping [Ni(II)6] Trigonal Prisms Including a [Ni6Dy3] Single-Molecule Magnet.

    PubMed

    Canaj, Angelos B; Tzimopoulos, Demetrios I; Siczek, Milosz; Lis, Tadeusz; Inglis, Ross; Milios, Constantinos J

    2015-07-20

    The use of (2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) ligand, H3L, in Ni/Ln chemistry has led to the isolation of three new isostructural [Ni(II)6Ln(III)3] metallic cages. More specifically, the reaction of Ni(ClO4)2·6H2O, the corresponding lanthanide nitrate salt, and H3L in MeCN, under solvothermal conditions in the presence of NEt3, led to the isolation of three complexes with the formulas [Ni6Gd3(OH)6(HL)6(NO3)3]·5.75MeCN·2Et2O·1.5H2O (1·5.75MeCN·2Et2O·1.5H2O), [Ni6Dy3(OH)6(HL)6(NO3)3]·2MeCN·2.7Et2O·2.4H2O (2·2MeCN·2.7Et2O·2.4H2O), and [Ni6Er3(OH)6(HL)6(NO3)3]·5.75MeCN·2Et2O·1.5H2O (3·5.75MeCN·2Et2O·1.5H2O). The structure of all three clusters describes a [Ln(III)3] triangle capping a [Ni(II)6] trigonal prism. Direct current magnetic susceptibility studies in the 5-300 K range for complexes 1-3 reveal the different nature of the magnetic interactions within the clusters: dominant antiferromagnetic exchange interactions for the Dy(III) and Er(III) analogues and dominant ferromagnetic interactions for the Gd(III) example. Alternating current magnetic susceptibility measurements under zero external dc field displayed fully formed temperature- and frequency-dependent out-of-phase peaks for the [Ni(II)6Dy(III)3] analogue, establishing its single molecule magnetism behavior with Ueff = 24 K. PMID:26135204

  2. Transparent glass-ceramics containing Eu3+ and Dy3+ ions for visible optoelectronics

    NASA Astrophysics Data System (ADS)

    Pisarska, Joanna; Żur, Lidia; Pisarski, Wojciech A.

    2011-06-01

    Selected oxyfluoride glasses containing Eu3+ and Dy3+ were heat treated in order to obtain transparent glass-ceramics. Visible emission spectra corresponding to 5D0 - 7FJ (J = 0, 1, 2, 3, 4) transitions of Eu3+ and 4F9/2 - 6HJ/2 (J = 11, 13, 15) transitions of Dy3+ in glass samples before and after heat treatment were registered. The luminescence intensity ratios R (Eu3+) and Y/B (Dy3+) have been analyzed in details. Their values are reduced due to part incorporation of rare earth ions into cubic β-PbF2 crystalline phase.

  3. Helium-induced one-neutron transfer to levels in 162Dy

    NASA Astrophysics Data System (ADS)

    Andersen, E.; Helstrup, H.; Løvhøiden, G.; Thorsteinsen, T. F.; Guttormsen, M.; Messelt, S.; Tveter, T. S.; Hofstee, M. A.; Schippers, J. M.; van der Werf, S. Y.

    1992-12-01

    Levels in 162Dy have been studied in the 161Dy(α, 3He) and 163Dy( 3He, α) reactions with 50 MeV α- and 3He-beams from the KVI cyclotron in Groningen. The reaction products were analyzed in the QMG/2 magnetic spectrograph and registered in a two-dimensional detector system. The observed levels and cross sections are well described by the Nilsson model with the exception of the three levels at 1578, 1759 and 1990 keV. The present data combined with previous results strongly indicate that these levels are the spin-4, -6, and -8 members of the S-band.

  4. Far infrared properties of the rare-earth scandate DyScO3.

    PubMed

    Baldassarre, L; Perucchi, A; Lupi, S; Dore, P

    2010-09-01

    We present reflectance measurements in the infrared region on a single crystal the rare-earth scandate DyScO(3). Measurements performed between room temperature and 10 K allow us to determine the frequency of the infrared-active phonons, never investigated experimentally, and to get information on their temperature dependence. A comparison with the phonon peak frequency resulting from ab initio computations is also provided. We finally report detailed data on the frequency dependence of the complex refractive index of DyScO(3) in the terahertz region, which is important in the analysis of terahertz measurements on thin films deposited on DyScO(3). PMID:21403288

  5. Radio-frequency magnetic susceptibility of spin ice crystals Dy2Ti2O7 using tunnel diode resonator

    NASA Astrophysics Data System (ADS)

    Teknowijoyo, Serafim; Cho, Kyuil; Tanatar, Makariy A.; Prozorov, Ruslan; Cava, Robert J.; Krizan, Jason W.; Ames Laboratory; Iowa State University Team; Princeton University Collaboration

    Spin ice compound, Dy2Ti2O7, has shown complex frequency - dependent magnetic behavior at low temperatures. While the DC measurements show conventional paramagnetic behavior, finite frequency susceptibility shows two regimes, - complex kagomé ice behavior at around 2 K and spin collective behavior above 10 K, depending on the frequency. Conventional AC susceptometry is limited to frequencies in a kHz range, but to get an insight into the possible Arrhenius activated behavior and characteristic relaxation times, higher frequencies are desired. We used self-oscillating tunnel-diode resonator (TDR) to probe magnetic susceptibility at 14.6 MHz, in the presence of a DC magnetic field and down to 50 mK. We found an unusual non-monotonic field dependence of the lower transition temperature, most likely associated with different spin configurations in a kagomé ice and an activated behavior of the upper transition, which has now shifted to 50 K range. This work was supported by the U.S. DOE BES MSED and was performed at the Ames Laboratory, Iowa State University under Contract DE-AC02-07CH11358. The work at Princeton university was supported by DOE BES Grant Number DE-FG02-08ER46544.

  6. A salen-type Dy4 single-molecule magnet with an enhanced energy barrier and its analogues.

    PubMed

    Luan, Fang; Yan, Pengfei; Zhu, Jing; Liu, Tianqi; Zou, Xiaoyan; Li, Guangming

    2015-03-01

    Four isomorphic tetranuclear lanthanide complexes, namely [Ln4(L)2(HL)2(NO3)2(OH)2](NO3)2·4H2O (Ln = Dy (1); Tb (2); Ho (3); Er (4)), constructed using hexadentate salen-type ligand N,N'-bis(3-methoxy-salicylidene)cyclohexane-1,2-diamine, have been isolated. X-ray crystallographic analysis reveals that all of the complexes 1-4 are of discrete tetranuclear structure with a unique {Ln4O8} core in which four lanthanide ions are coplanar in a rhombic frame. There are two crystallographically unequivalent lanthanide ions, that is the Ln1(III) ion which is nine-coordinated in a monocapped square-antiprismatic geometry of the C(4v) point group and the Ln2(III) ion which is eight-coordinated in a distorted bicapped trigonal-prismatic geometry of the C(2v) point group. Magnetic analysis reveals that complex 1 exhibits two slow magnetic relaxations with the highest energy barrier among the reported tetranuclear salen-type dysprosium SMMs. This further extends the available SMMs of salen-type lanthanide complexes. PMID:25619145

  7. Squaring the cube: a family of octametallic lanthanide complexes including a Dy8 single-molecule magnet.

    PubMed

    Fang, Ming; Zhao, Hanhua; Prosvirin, Andrey V; Pinkowicz, Dawid; Zhao, Bin; Cheng, Peng; Wernsdorfer, Wolfgang; Brechin, Euan K; Dunbar, Kim R

    2013-10-01

    A series of isostructural octanuclear lanthanide complexes of general formula [Ln8(sao)4(μ3-OH)4(NO3)12(DMF)12] (Ln = Nd (), Sm (), Eu (), Gd (), Tb (), Dy (), Ho (), Er (); DMF = dimethylformamide) have been prepared via reactions of salicylaldoxime (saoH2), tetramethylammonium hydroxide (Me4NOH) with the appropriate lanthanide nitrate salt (Ln(NO3)3·6H2O). The metallic skeletons of the complexes describe [Ln4] tetrahedra encapsulated inside a [Ln4] square with the inner core stabilised through μ3-OH(-) ions and the periphery by μ4-sao(2-) ligands. The magnetic properties of compounds were investigated by dc and ac magnetometry. Temperature dependent ac magnetic susceptibility data reveal that the dysprosium analogue () displays an out-of-phase signal in the absence of an applied magnetic field indicative of slow relaxation of the magnetization typical of a Single-Molecule Magnet (SMM). Micro-SQUID measurements reveal temperature and sweep rate dependent hysteresis below 1.0 K. PMID:23943045

  8. Decay of /sup 150/Er

    SciTech Connect

    Moltz, D.M.; Toth, K.S.; Ellis-Akovali, Y.A.; Cole, J.D.

    1982-09-01

    A new activity, T/sub 1/2/ = 20 +- 2 sec, was observed in /sup 12/C bombardments of /sup 144/Sm. Only one ..gamma.. ray, 476.0 +- 0.1 keV, was found to be associated with this nuclide. We identify the new isotope as /sup 150/Er and propose that it decays mainly to one level in /sup 150/Ho at an excitation energy of approx.476 keV by an allowed ..beta.. transition which connects states with the following configurations: O/sup +/(..pi..h/sub 11/2/, ..pi..h/sub 11/2/)..-->..1/sup +/(..pi..h/sub 11/2/,..nu..h/sub 9/2/). As part of the investigation, the decay properties of the high- and low-spin /sup 150/Ho isomers were reexamined.

  9. Optical spectra and crystal field analysis of Dy3+ in Cs2NaDyCl6 and Cs2NaYCl6: Dy3+(5 mol %)

    NASA Astrophysics Data System (ADS)

    Foster, David R.; Richardson, F. S.

    1985-02-01

    Optical absorption and emission measurements are reported for the Cs2NaDyCl6 and Cs2NaYCl6: Dy3+(5 mol %) systems under variable-temperature (10-298 K) conditions. For both systems, the data are compatible with the retention of octahedral (Oh) site symmetry at the Dy3+ ions over the entire 298 to 10 K temperature range. The only differentiation between the systems is the much greater quantum efficiency of 4F9/2 emission in the doped system vs that in the neat system. Forty-five crystal-field levels spanning 18 multiplets of the Dy3+ 4f9 electronic configuration are located and assigned, and an additional 12 crystal-field levels associated with six other multiplet manifolds are located, but left unassigned. These energy level results are analyzed on the basis of a nine-parameter 4f-electron Hamiltonian operating within a complete Russell-Saunders (SLJ) basis set for the 4f9 configuration of Dy3+. The most intense electric-dipole vibronic lines observed in the optical spectra are assigned to one-phonon vibronic transitions associated with the three odd-parity ``moiety'' modes of the DyCl3-6 octahedral clusters: ν3(t1u), ν4(t1u), and ν6(t2u). Intensity calculations are reported for both the no-phonon magnetic-dipole (origin) transitions and the one-phonon (ν3, ν4, and ν6) electric-dipole vibronic transitions.

  10. Are Wnts Retrogradely Transported to the ER?

    PubMed

    Tang, Bor Luen

    2016-11-01

    A recent report showed that Drosophila miR-307a initiates endoplasmic reticulum (ER) stress in wingless (wg)-expressing cells by suppression of the evolutionarily conserve Wnt secretion factor Wntless (Wls). Interestingly, the authors noted that wg has a putative C-terminal dilysine motif (KKVY), which is required for its apparent retrograde Golgi-to-ER transport. Wls suppression resulted in ER stress, which was phenocopied by several other manipulations that impaired wg secretion in flies, as well as Wnt5a secretion in mammalian cells. The authors surmised that their data "reveals a previously unknown Golgi-to-ER retrograde route of wg, and elucidates a correlation between Wnt secretion and ER stress." However, there are obvious caveats to this interpretation, as ER stress resulting from Wnt secretion impairment could be readily explained by its inability to leave the ER, and not resulting from Golgi-to-ER retrograde transport. J. Cell. Physiol. 231: 2315-2316, 2016. © 2016 Wiley Periodicals, Inc. PMID:26916992

  11. BOREAS Level-0 ER-2 Aerial Photography

    NASA Technical Reports Server (NTRS)

    Newcomer, Jeffrey A.; Dominquez, Roseanne; Hall, Forrest G. (Editor)

    2000-01-01

    For BOReal Ecosystem-Atmosphere Study (BOREAS), the ER-2 and other aerial photography was collected to provide finely detailed and spatially extensive documentation of the condition of the primary study sites. The ER-2 aerial photography consists of color-IR transparencies collected during flights in 1994 and 1996 over the study areas.

  12. On the change of period of DY Pegasi

    NASA Astrophysics Data System (ADS)

    Jiang, S.-Y.; Zhao, N.-S.

    1982-06-01

    A high-speed three-channel photon-counting photometer was used on three nights to observe DY Peg, an ultrashort-period Cepheid of the AI Vel type. Seven epochs of maximum and two sets of O-C values are determined. The results are combined with data obtained over the past 30 yr to recalculate both the equation for the epoch of maximum and the rate of period change. The period decay rate is found to be (6.3 + or - 0.2) x 10 to the -12th day/day, which corresponds to a period decrease of (3.1 + or - 0.1) x 10 to the -8th per yr. It is concluded that certain random factors are present in the star's period changes.

  13. Scissors Mode of 162 Dy Studied from Resonance Neutron Capture

    DOE PAGESBeta

    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.; et al

    2015-05-28

    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,more » (n,γ) experiments on Gd isotopes, and (γ,γ’) reactions.« less

  14. Transition Strength Ratios in the Tetrahedral Candidate ^156Dy

    NASA Astrophysics Data System (ADS)

    Hartley, D. J.; Riedinger, L. L.; Curien, D.; Dudek, J.; Gall, B.; Allmond, J. M.; Beausang, C. W.; Carpenter, M. P.; Chiara, C. J.; Janssens, R. V. F.; Kondev, F. G.; Lauritsen, T.; McCutchan, E. A.; Stefanescu, I.; Zhu, S.; Garrett, P. E.; Kulp, W. D.; Wood, J. L.; Mazurek, K.; Riley, M. A.; Wang, X.; Schunck, N.; Yu, C.-H.; Sharpey-Schafer, J.; Simpson, J.

    2009-10-01

    A new symmetry has been recently proposed where nuclei may stabilize in a tetrahedral (pyramid) shape. One of the consequences of this symmetry is that the transition strength, B(E2), of the inband transitions should approach zero in the ideal case. Thus, one signal of this exotic shape would be a rotational band where the inband E2 transitions are extremely weak or nonexistent. Such bands exist in many of the lowest negative-parity bands in the N 90 nuclei, which is also a predicted ``magic" region for tetrahedral symmetry. A Gammasphere experiment was performed to measure the B(E2)/B(E1) ratios of such a negative-parity band in ^156Dy. The results (which are consistent with the theory) will be presented, as well as a discussion of the proposed follow-up experiment to directly measure the B(E2) rates.

  15. Scissors Mode of 162Dy Studied from Resonance Neutron Capture

    NASA Astrophysics Data System (ADS)

    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.

  16. Spectral Properties of Dy-Doped Thermal Barrier Sensor Coatings

    SciTech Connect

    Allison, Stephen W; Moore, Danielle; Heyes, Andrew; Nichols, John R.

    2009-01-01

    We have obtained the excitation (484, 497 and 585 nm) and emission (355, 367 and 385 nm) spectra and measured the fluorescence decay lifetimes for partially Y2O3 stabilized ZrO2 thermal barrier coatings doped with 2mol% Dy2O3, as a function of coating depth for thicknesses ranging from 30 to 200 μm. In principle, these coatings can function not only as thermal protection barriers for turbomachinery blades and vanes, but also as remotely interrogated self-sensors for use in determining in situ wear rates during operation. This is done by varying the excitation wavelength and observing the fluorescence decay times and related parameters.

  17. Magnetization and magnetic susceptibility of DyH3

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1974-01-01

    The magnetization and differential magnetic susceptibility of powdered samples of DyH3 have been measured at 4.2 K in applied magnetic fields ranging to 9 Teslas. The differential magnetic susceptibility has also been studied in zero applied field as a function of temperature. The magnetization data are described by an equation of the form M = aB/(1 + bB + cB. The ratio a/b is a measure of the saturation magnetization and gives an effective moment of 5.12 Bohr magnetons per ion. The zero field susceptibility exhibits a maximum at T = 3.45 K, and an inflection point near 2.85 K. The susceptibility at 4.2 K has a 1/B squared dependence on the applied magnetic field for B approximately greater than 0.3 Teslas.

  18. Magnetization and magnetic susceptibility of DyH3

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1975-01-01

    The magnetization and differential magnetic susceptibility of powdered DyH3 samples are measured at a temperature of 4.2 K in applied magnetic fields ranging up to 9 Teslas. The differential magnetic susceptibility is also investigated in the zero applied field. Magnetization is plotted as a function of field strength, and differential susceptibility is described as a function of both field strength and temperature. A saturation magnetic moment of 5.12 Bohr magnetons per ion is derived from the magnetization data, and the zero-field susceptibility measurements are found to indicate antiferromagnetic ordering below 3.45 K. The susceptibility at 4.2 K is shown to have an inverse-square dependence on field strength for values of not less than 0.3 Tesla.

  19. Magnetic structures of nanometer scale Dy, Cr and Ni

    SciTech Connect

    Fitzsimmons, M.R.; Robinson, R.A.; Lawson, A.C.; Kwei, G.H.; Sickafus, K.E.; Eastman, J.A.; Burkel, E.

    1992-10-01

    Materials composed of nanometer-sized structures are becoming technologically relevant as the sizes of electronic devices approach the nanometer scale. Questions as to the performance and durability of these devices can be partially addressed through the characterization and understanding of the magnetic structures and properties of nanometer-sized materials. The purpose of the present work is to understand the relationship between the microstructure of nanocrystalline materials and their magnetic structures and properties. This paper summarizes three separate experiments: (1) an X-ray diffraction and anomalous absorption (XANES) study of nanocrystalline Dy, (2) neutron diffraction measurements of the magnetic structure of nanocrystalline Cr, and (3) the measurement of the magnetization density of a single twist grain boundary in Ni.

  20. 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

    SciTech Connect

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

    2015-05-15

    earth compounds. The variation of alloy’s composition by ~3 at% i.e. from Dy{sub 2}Ni{sub 2.35}Si{sub 0.65} to Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} leads to significant transformation of crystal structure of compound with different variant of distortion of Po-type rare earth sublattice, as in Gd–Co–Ga and Er–Ni–In systems: the Mo{sub 2}NiB{sub 2}-type Gd{sub 2}Co{sub 2}Ga and La{sub 2}Ni{sub 3}-type Gd{sub 2}Co{sub 2.9}Ga{sub 0.1}, and Mo{sub 2}FeB{sub 2}-type Er{sub 2}Ni{sub 1.78}In and Mn{sub 2}AlB{sub 2}-type Er{sub 2}Ni{sub 2}In. Magnetization measurements indicate collinear ferromagnetic ordering of Mo{sub 2}NiB{sub 2}-type Gd{sub 2}Ni{sub 2.35}Si{sub 0.65} and a complex antiferromagnetic ordering with low-temperature metamagnetic nature for Mo{sub 2}NiB{sub 2}-type Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} compounds. However, neutron diffraction study in zero applied field of Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} reveals c-axis pure antiferromagnetic ordering of terbium sublattice with K=[1/2, 0, 1/2] propagation vector. Magnetization measurements indicate ferromagnetic order with coexisting antiferromagnetic interactions and low-temperature metamagnetic state for La{sub 2}Ni{sub 3}-type Dy{sub 2}Ni{sub 2.5}Si{sub 0.5}. We suggest possible polymorphism in other Mo{sub 2}FeB{sub 2}-type, Mo{sub 2}NiB{sub 2}-type, La{sub 2}Ni{sub 3}-type and Mn{sub 2}AlB{sub 2}-type rare earth compounds with corresponding change in their magnetic properties. - Highlights: • (Gd, Tb, Dy){sub 2}Ni{sub 2.35}Si{sub 0.65} compounds crystallize in the Mo{sub 2}NiB{sub 2}-type structure. • (Dy, Ho){sub 2}Ni{sub 2.5}Si{sub 0.5} compounds crystallize in the La{sub 2}Ni{sub 3}-type structure. • Gd{sub 2}Ni{sub 2.35}Si{sub 0.65} shows pure ferromagnetic type ordering. • Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} and Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} show mixed ferro-antiferromagnetic ordering. • Tb{sub 2}Ni{sub 2.35}Si{sub 0.65} and Dy{sub 2}Ni{sub 2.5}Si{sub 0.5} exhibit low-temperature metamagnetic

  1. Mutational Analysis of the Drosophila Miniature-Dusky (M-Dy) Locus: Effects on Cell Size and Circadian Rhythms

    PubMed Central

    Newby, L. M.; White, L.; DiBartolomeis, S. M.; Walker, B. J.; Dowse, H. B.; Ringo, J. M.; Khuda, N.; Jackson, F. R.

    1991-01-01

    A mutational analysis has been performed to explore the function of the Drosophila melanogaster miniature-dusky (m-dy) locus. Mutations at this locus affect wing development, fertility and behavior. The genetic characterization of 13 different mutations suggests that m and dy variants are alleles of a single complex gene. All of these mutations alter wing size, apparently by reducing the volume of individual epidermal cells of the developing wing. In m mutants, epidermal cell boundaries persist in the mature wing, whereas they normally degenerate 1-2 hr after eclosion in wild-type or dy flies. This has permitted the direct visualization of cell size differences among several m mutants. Mutations at the m-dy locus also affect behavioral processes. Three out of nine dy alleles (dy(n1), dy(n3) and dy(n4)) lengthen the circadian period of the activity and eclosion rhythms by approximately 1.5 hr. In contrast, m mutants have normal circadian periods, but an abnormally large percentage of individuals express aperiodic bouts of activity. These behavior genetic studies also indicate that an existing ``rhythm'' mutation known as Andante is an allele of the m-dy locus. The differential effects of certain m-dy mutations on wing and behavioral phenotypes suggest that separable domains of function exist within this locus. PMID:1908397

  2. Facilitative plasma membrane transporters function during ER transit

    PubMed Central

    Takanaga, Hitomi; Frommer, Wolf B.

    2010-01-01

    Although biochemical studies suggested a high permeability of the endoplasmic reticulum (ER) membrane for small molecules, proteomics identified few specialized ER transporters. To test functionality of transporters during ER passage, we tested whether glucose transporters (GLUTs, SGLTs) destined for the plasma membrane are active during ER transit. HepG2 cells were characterized by low-affinity ER transport activity, suggesting that ER uptake is protein mediated. The much-reduced capacity of HEK293T cells to take up glucose across the plasma membrane correlated with low ER transport. Ectopic expression of GLUT1, -2, -4, or -9 induced GLUT isoform-specific ER transport activity in HEK293T cells. In contrast, the Na+-glucose cotransporter SGLT1 mediated efficient plasma membrane glucose transport but no detectable ER uptake, probably because of lack of a sufficient sodium gradient across the ER membrane. In conclusion, we demonstrate that GLUTs are sufficient for mediating ER glucose transport en route to the plasma membrane. Because of the low volume of the ER, trace amounts of these uniporters contribute to ER solute import during ER transit, while uniporters and cation-coupled transporters carry out export from the ER, together potentially explaining the low selectivity of ER transport. Expression levels and residence time of transporters in the ER, as well as their coupling mechanisms, could be key determinants of ER permeability.—Takanaga, H., Frommer, W. B. Facilitative plasma membrane transporters function during ER transit. PMID:20354141

  3. Identification and molecular characterization of a novel DyP-type peroxidase from Pseudomonas aeruginosa PKE117.

    PubMed

    Li, Jing; Liu, Chen; Li, Baozhen; Yuan, Hongli; Yang, Jinshui; Zheng, Beiwen

    2012-02-01

    A new DyP-type peroxidase from Pseudomonas aeruginosa PKE117 was identified and characterized. The dypPa was first identified via sequence analysis and then cloned in Escherichia coli. Subsequently, the recombinant protein DyPPa was expressed and purified. Its DNA sequence analysis revealed an open reading frame of 897 bp, encoding a protein monomer of 299 amino acid residues with isoelectric point 4.62. According to SDS-PAGE analysis and FPLC result, DyPPa mainly existed as homodimer (64 kDa). DyPPa displayed typical heme absorbance of Soret band, with an Rz value of 1.18. Inductively coupled plasma-atomic absorption spectrum data also indicated DyPPa contained iron. Multiple amino acid sequence alignment of DyPPa with other members of the DyP-type peroxidases family showed the presence of conserved D139, H210, and R227 amino acids and GXXDG motifs, which were commonly shared by the DyP-type peroxidase family. Although the primary structure homology between DyPPa and other family members was very low, their secondary and tertiary structure displayed high homology, which explained the high decolorizing activity of DyPPa. Specifically, DyPPa displayed a good thermal stability and maximal activity on Reactive blue 5 under pH 3.5. Therefore, it was proposed that DyPPa, with a wide range of substrate specificity, was a novel member of the DyP-type peroxidases family. PMID:22161141

  4. Tailoring of magnetic properties of ultrathin epitaxial Fe films by Dy doping

    SciTech Connect

    Baker, A. A.; Figueroa, A. I.; Laan, G. van der; Hesjedal, T.

    2015-07-15

    We report on the controlled modification of relaxation parameters and magnetic moments of epitaxial Fe thin films through Dy doping. Ferromagnetic resonance measurements show that an increase of Dy doping from 0.1% to 5% gives a tripling in Gilbert damping, and more importantly a strongly enhanced anisotropic damping that can be qualitatively understood through the slow-relaxing impurity model. X-ray magnetic circular dichroism measurements show a pronounced suppression of the orbital moment of the Fe with Dy doping, leading to an almost threefold drop in the orbital to spin moment ratio, m{sub l}/m{sub s}. Doping with Dy can therefore be used to control both dynamic and static properties of thin ferromagnetic films for improved performance in spintronics device applications, mediated through the antiferromagnetic interaction of the 4f and 3d states.

  5. C-Axis Properties of DyNi2B2C System

    NASA Astrophysics Data System (ADS)

    Lee, W. C.

    2012-02-01

    We have measured the electrical resistivity along c-axis ρc(T, H) of the DyNi2B2C single crystal with the magnetic fields perpendicular to the c-axis and the magnetization isotherms M(H) of the DyNi2B2C single crystal with magnetic fields perpendicular and parallel to the c-axis. We confirmed that Neel temperature TN is 10.3K from the ρc(T) result which is consistent with that from previous ρab(T) result. In addition, the constructed critical fields Hc2(T) curve and magnetic transitions diagram of DyNi2B2C from ρc(T) magnetic fields perpendicular to c-axis is similar to that of ρab(T) result, which is thought to arise that 3 D magnetic structure of DyNi2B2C.

  6. Simultaneous occurrence of multiferroism and short-range magnetic order in DyFeO3

    DOE PAGESBeta

    Wang, Jinchen; Liu, Juanjuan; Sheng, Jieming; Luo, Wei; Ye, Feng; Zhao, Zhiying; Sun, Xuefeng; Danilkin, Sergey A.; Deng, Guochu; Bao, Wei

    2016-04-06

    In this paper, we present a combined neutron scattering and magnetization study on the multiferroic DyFeO3, which shows a very strong magnetoelectric effect. Applying magnetic field along the c axis, the weak ferromagnetic order of the Fe ions is quickly recovered from a spin reorientation transition, and the long-range antiferromagnetic order of Dy becomes a short-range one. We found that the short-range order concurs with the multiferroic phase and is responsible for its sizable hysteresis. In conclusion, our H-T phase diagram suggests that the strong magnetoelectric effect in DyFeO3 has to be understood with not only the weak ferromagnetism ofmore » Fe but also the short-range antiferromagnetic order of Dy.« less

  7. Magnetization reversal mechanism of a sintered Nd-Fe-B magnet with Dy segregation

    SciTech Connect

    Suzuki, Hiroyuki; Satsu, Yuichi; Komuro, Matahiro; Kohashi, Teruo; Motai, Kumi

    2011-04-01

    The magnetization reversal mechanism of a sintered Nd-Fe-B magnet with Dy segregation near grain boundaries (GB) was studied using spin polarized scanning electron spectroscopy and magnetization measurements. More fine magnetic domains near GB were found in the magnet with Dy segregation than in the magnet without treatment. Magnetic modifications near the GB had no effect on the magnetization development. The domain wall motion of a quasihard magnetic component in the magnet with Dy segregation was suppressed in comparison with those in the magnet without treatment; this could also be confirmed in the different behaviors of asymmetry components toward a magnetic field direction between both magnets. From analyzing the probability of rotating magnetization near the GB, the magnetization reversal of the magnet with Dy segregation was more difficult to produce than those of the magnet without treatment.

  8. Multiple superhyperfine fields in a {DyFe2Dy} coordination cluster revealed using bulk susceptibility and (57)Fe Mössbauer studies.

    PubMed

    Peng, Yan; Mereacre, Valeriu; Anson, Christopher E; Powell, Annie K

    2016-08-01

    A [DyFeDy(μ3-OH)2(pmide)2(p-Me-PhCO2)6] coordination cluster, where pmideH2 = N-(2-pyridylmethyl)iminodiethanol, has been synthesized and the magnetic properties studied. The dc magnetic measurements reveal dominant antiferromagnetic interactions between the metal centres. The ac measurements reveal zero-field quantum tunnelling of the magnetisation (QTM) which can be understood, but not adequately modelled, in terms of at least three relaxation processes when appropriate static (dc) fields are applied. To investigate this further, (57)Fe Mössbauer spectroscopy was used and well-resolved nuclear hyperfine structures could be observed, showing that on the Mössbauer time scale, without applied field or else with very small applied fields, the iron nuclei experience three or more superhyperfine fields arising from the slow magnetisation reversal of the strongly polarized fields of the Dy(III) ions. PMID:27424877

  9. Research on the properties of dope-dyed bamboo pulp staple fibers

    NASA Astrophysics Data System (ADS)

    Zhang, Y. J.

    2016-07-01

    In order to understand the properties of the dope-dyed bamboo pulp staple fibers, the moisture regains, tensile properties, friction properties and electrical conductivity of them and the white bamboo pulp fiber were tested, compared and analyzed. The results show that the moisture regains of the dope-dyed bamboo pulp fibers are smaller than the white bamboo pulp fiber's, whereas their friction coefficients, breaking strengths and elongations and mass ratio resistances are a bit larger.

  10. Report on the Photometric Observations of the Variable Stars DH Pegasi, DY Pegasi, and RZ Cephei

    NASA Astrophysics Data System (ADS)

    Abu-Sharkh, I.; Fang, S.; Mehta, S.; Pham, D.

    2014-12-01

    We report 872 observations on two RR Lyrae variable stars, DH Pegasi and RZ Cephei, and on one SX Phoenicis variable, DY Pegasi. This paper discusses the methodology of our measurements, the light curves, magnitudes, epochs, and epoch prediction of the above stars. We also derived the period of DY Pegasi. All measurements and analyses are compared with prior publications and known values from multiple databases.

  11. A luminescent heptanuclear DyIr6 complex showing field-induced slow magnetization relaxation.

    PubMed

    Zeng, Dai; Ren, Min; Bao, Song-Song; Li, Li; Zheng, Li-Min

    2014-08-01

    The first example of iridium/lanthanide phosphonates, i.e. [DyIr6(ppy)12(bpp)2(bppH)4](CF3SO3)·8H2O (1) (ppy(-) = 2-phenylpyridine, bpp(2-) = 2-pyridylphosphonate) is reported. It shows dual functions with the photoluminescence and field-induced slow magnetization relaxation originating from the Ir and Dy moieties, respectively. PMID:24942060

  12. An Undecanuclear Ferrimagnetic Cu9Dy2 Single Molecule Magnet Achieved through Ligand Fine-Tuning.

    PubMed

    Kühne, Irina A; Kostakis, George E; Anson, Christopher E; Powell, Annie K

    2016-05-01

    We describe the concept of increasing the nuclearity of a previously reported high-spin Cu5Gd2 core using a "fine-tuning" ligand approach. Thus, two Cu9Ln2 coordination clusters, with Ln = Dy (1) and Gd (2), were synthesized with the Gd compound having a ground spin state of (17)/2 and the Dy analogue showing single-molecule-magnet behavior in zero field. PMID:27096219

  13. Thermoluminescence in β-irradiated SrZnF4:Dy TLD phosphor

    NASA Astrophysics Data System (ADS)

    Shelke, Tushar R.; Dhoble, S. J.; Nanoti, V. M.

    2014-02-01

    SrZnF4:Dy phosphor was prepared by the wet chemical synthesis and characterized for its X-ray diffraction, thermoluminescence (TL) and photoluminescence (PL) properties. The PL emission spectra for SrZnF4:Dy3+ phosphor at 351 nm excitation give emission at 481 nm (blue) and 575 nm (yellow). The TL properties of SrZnF4:Dy were studied using β-irradiation. The response curve of the prepared phosphor with high-dose β-ray exposure is linear as compared with well-known CaSO4:Dy phosphor. The TL glow curves of SrZnF4:Dy sample showed two well-defined peaks at 143°C (peak-1) and 231°C (peak-2) indicating that two sets of traps are being activated within the particular temperature range and the trapping parameter associated with the prominent glow peaks of SrZnF4:Dy is calculated by using Chen's method.

  14. Synthesis, chemical bonding and physical properties of RERhB{sub 4} (RE=Y, Dy-Lu)

    SciTech Connect

    Veremchuk, I.; Mori, T.; Prots, Yu.; Schnelle, W.; Leithe-Jasper, A.; Kohout, M.; Grin, Yu.

    2008-08-15

    The compounds of rare-earth metals with rhodium and boron RERhB{sub 4} (RE=Y, Dy-Lu) crystallize with the orthorhombic structure type YCrB{sub 4} (space group Pbam, Pearson symbol oP24). The crystal structures of the compounds with RE=Y, Er, Tm and Yb were refined by using single-crystal diffraction data. Analysis of chemical bonding for YRhB{sub 4} and YbRhB{sub 4} was performed by electron localizability indicator and by calculation of quantum chemical charges (quantum theory of atoms in molecules). Boron and rhodium form the 3-D polyanion containing planar nets of three-bonded boron atoms interconnected by rhodium along [001]. The interaction of the RE species with the rhodium-boron polyanion is predominantly ionic. Magnetic susceptibility data of TmRhB{sub 4} and YbRhB{sub 4} showed that the RE species are in 4f{sup 12} (Tm) and 4f{sup 13} (Yb) electronic states, respectively. In the low-temperature region, the specific heat revealed a Schottky anomaly for TmRhB{sub 4} while an antiferromagnetic transition is observed at 3.5 K for YbRhB{sub 4}. X-ray absorption measurement at the Yb L{sub III} edge for YbRhB{sub 4} reveals the 4f{sup 13} state of ytterbium. - Graphical abstract: The compounds of rare-earth metals with rhodium and boron RERhB{sub 4} (RE=Y, Dy-Lu) crystallize with the orthorhombic structure type YCrB{sub 4}. Analysis of chemical bonding for YRhB{sub 4} and YbRhB{sub 4} was performed by electron localizability indicator and by calculation of quantum chemical charges (quantum theory of atoms in molecules). Boron and rhodium form the 3-D polyanion containing planar nets of three-bonded boron atoms interconnected by rhodium along [001]. The interaction of the RE species with the rhodium-boron polyanion is predominantly ionic.

  15. ER Screenings Could Help Prevent Suicide

    MedlinePlus

    ... fullstory_158246.html ER Screenings Could Help Prevent Suicide: Study Checking patients for risk factors should be ... News) -- Routine screening of emergency room patients for suicide risk might be an effective way to prevent ...

  16. Edible Pot Sends Toddlers to Colorado ERs

    MedlinePlus

    ... html Edible Pot Sends Toddlers to Colorado ERs Cannabis-laced candy, baked goods look irresistible to kids, ... became the first two states to legalize recreational marijuana. Shortly after, a sharp increase occurred in the ...

  17. Environmental release summary (ERS) database CY 1997

    SciTech Connect

    Gleckler, B.P.

    1998-07-01

    This report discusses the Environmental Release Summary (ERS) database. The current needs of the Effluent and Environmental database is continually modified to fulfill monitoring (EEM) program (managed by Waste Management Federal Services of Hanford, Incorporated, Air and Water Services Organization). Changes are made to accurately calculate current releases, to affect how past releases are calculated. This document serves as a snap-shot of the database and software for the CY-1997 data and releases. This document contains all of the relevant data for calculating radioactive-airborne and liquid effluent. The ERS database is the official repository for the CY-1997 ERS release reports and the settings used to generate those reports. As part of the Tri-Party Agreement, FDH is committed to provide a hard copy of the ERS database for Washington State Department of Ecology, upon request. This document also serves as that hard copy for the last complete calendar year.

  18. FIRE_ACE_ER2_MAS

    Atmospheric Science Data Center

    2015-10-28

    ... First ISCCP Regional Experiment (FIRE) Arctic Cloud Experiment (ACE) NASA ER-2 Moderate Resolution Imaging ... SSFR Location:  Northern Alaska Arctic Ocean Spatial Coverage:  Fairbanks, Alaska and the surrounding ...

  19. Structure and magnetic properties of hot deformed Nd2Fe14B magnets doped with DyHx nanoparticles

    NASA Astrophysics Data System (ADS)

    Wang, C. G.; Yue, M.; Zhang, D. T.; Liu, W. Q.; Zhang, J. X.

    2016-04-01

    Commercial NdFeB powders mixed with DyHx nanoparticles are hot pressed and hot deformed into anisotropic magnets by Spark Plasma Sintering (SPS). The hot deformed magnet exhibits strong c-axis crystallographic texture. The coercivity of the magnet doped with 1.0 wt% DyHx is increased by 66.7%, compared with the magnet without DyHx, while the remanence decreases only by 3%. TEM observation shows that there exists a continuous (Nd,Dy)2Fe14B layer between Nd-rich phase and NdFeB main phase.

  20. A distinct magnetic anisotropy enhancement in mononuclear dysprosium-sulfur complexes by controlling the Dy-ligand bond length.

    PubMed

    Liu, Shan-Shan; Lang, Ke; Zhang, Yi-Quan; Yang, Qian; Wang, Bing-Wu; Gao, Song

    2016-05-10

    In a field-induced single-ion magnet [(dtc)3Dy(phen)] (dtc(-) = diethyldithiocarbamate anion), replacing two of the S-based dtc(-) ligands with O-based dbm(-) ligands (dbm(-) = dibenzoylmethanoate anion) leads to a significant enhancement of magnetic anisotropy, yielding a rarely reported sulfur-ligated lanthanide-based single-ion magnet [(dbm)2Dy(dtc)(phen)]. Ab initio calculations reveal that the gz value of [(dbm)2Dy(dtc)(phen)] is much larger than that of [(dtc)3Dy(phen)], consistent with the experimental results. PMID:27090361

  1. Characterization of the ER-Targeted Low Affinity Ca(2+) Probe D4ER.

    PubMed

    Greotti, Elisa; Wong, Andrea; Pozzan, Tullio; Pendin, Diana; Pizzo, Paola

    2016-01-01

    Calcium ion (Ca(2+)) is a ubiquitous intracellular messenger and changes in its concentration impact on nearly every aspect of cell life. Endoplasmic reticulum (ER) represents the major intracellular Ca(2+) store and the free Ca(2+) concentration ([Ca(2+)]) within its lumen ([Ca(2+)]ER) can reach levels higher than 1 mM. Several genetically-encoded ER-targeted Ca(2+) sensors have been developed over the last years. However, most of them are non-ratiometric and, thus, their signal is difficult to calibrate in live cells and is affected by shifts in the focal plane and artifactual movements of the sample. On the other hand, existing ratiometric Ca(2+) probes are plagued by different drawbacks, such as a double dissociation constant (Kd) for Ca(2+), low dynamic range, and an affinity for the cation that is too high for the levels of [Ca(2+)] in the ER lumen. Here, we report the characterization of a recently generated ER-targeted, Förster resonance energy transfer (FRET)-based, Cameleon probe, named D4ER, characterized by suitable Ca(2+) affinity and dynamic range for monitoring [Ca(2+)] variations within the ER. As an example, resting [Ca(2+)]ER have been evaluated in a known paradigm of altered ER Ca(2+) homeostasis, i.e., in cells expressing a mutated form of the familial Alzheimer's Disease-linked protein Presenilin 2 (PS2). The lower Ca(2+) affinity of the D4ER probe, compared to that of the previously generated D1ER, allowed the detection of a conspicuous, more clear-cut, reduction in ER Ca(2+) content in cells expressing mutated PS2, compared to controls. PMID:27598166

  2. Topography over South America from ERS altimetry

    NASA Technical Reports Server (NTRS)

    Brenner, Anita; Frey, Herb; DiMarzio, John; Tsaoussi, Lucia

    1997-01-01

    The results of the surface topography mapping of South America during the ERS-1 geodetic mission are presented. The altimeter waveforms, the range measurement, and the internal and Doppler range corrections were obtained. The atmospheric corrections and solid tides were calculated. Comparisons between Shuttle laser altimetry and ERS-1 altimetry grid showed good agreement. Satellite radar altimetry data can be used to improve the topographic knowledge of regions for which only poor elevation data currently exist.

  3. Arctigenin alleviates ER stress via activating AMPK

    PubMed Central

    Gu, Yuan; Sun, Xiao-xiao; Ye, Ji-ming; He, Li; Yan, Shou-sheng; Zhang, Hao-hao; Hu, Li-hong; Yuan, Jun-ying; Yu, Qiang

    2012-01-01

    Aim: To investigate the protective effects of arctigenin (ATG), a phenylpropanoid dibenzylbutyrolactone lignan from Arctium lappa L (Compositae), against ER stress in vitro and the underlying mechanisms. Methods: A cell-based screening assay for ER stress regulators was established. Cell viability was measured using MTT assay. PCR and Western blotting were used to analyze gene and protein expression. Silencing of the CaMKKβ, LKB1, and AMPKα1 genes was achieved by RNA interference (RNAi). An ATP bioluminescent assay kit was employed to measure the intracellular ATP levels. Results: ATG (2.5, 5 and 10 μmol/L) inhibited cell death and unfolded protein response (UPR) in a concentration-dependent manner in cells treated with the ER stress inducer brefeldin A (100 nmol/L). ATG (1, 5 and 10 μmol/L) significantly attenuated protein synthesis in cells through inhibiting mTOR-p70S6K signaling and eEF2 activity, which were partially reversed by silencing AMPKα1 with RNAi. ATG (1-50 μmol/L) reduced intracellular ATP level and activated AMPK through inhibiting complex I-mediated respiration. Pretreatment of cells with the AMPK inhibitor compound C (25 μmol/L) rescued the inhibitory effects of ATG on ER stress. Furthermore, ATG (2.5 and 5 μmol/L) efficiently activated AMPK and reduced the ER stress and cell death induced by palmitate (2 mmol/L) in INS-1 β cells. Conclusion: ATG is an effective ER stress alleviator, which protects cells against ER stress through activating AMPK, thus attenuating protein translation and reducing ER load. PMID:22705729

  4. Recent Advances with ER Targeted Intrabodies.

    PubMed

    Marschall, Andrea L J; Dübel, Stefan; Böldicke, Thomas

    2016-01-01

    ER intrabodies are recombinant antibody fragments produced and retained in the endoplasmatic reticulum (ER) of a cell or an organism with the purpose to induce phenotypes generated by interfering with the intracellular processing or by changing the location of the recognized antigen. The most common application is the generation of functional knockdowns of membrane proteins, which cannot reach their natural location on the cell surface when they are retained in the ER by the intrabody. Phenotypes generated by interfering with the secretion of extracellular or plasma proteins can be analyzed in a similar way. So far, most ER intrabody studies relied on scFv fragments subcloned from hybridoma lines. Recently, several large international research consortia have started to provide antibodies, with the final goal to cover substantial parts of the human proteome. For practical reasons of throughput and effort, in these consortia the most appropriate method to generate the necessary large numbers of monoclonal antibodies is in vitro selection, typically employing phage or yeast display. These methods provide the antibody genes right from the start, thereby facilitating the application of ER antibody approaches. On the other end, the first transgenic mice expressing an ER intrabody has recently been described. This moves the ER intrabody approach finally to level with classic in vivo knockout strategies - but also offers novel capabilities to the researchers. Promising new perspectives may originate from the fact that the knockdown is restricted to the protein level, that a graded knockdown strength can be achieved, or that the targeting of individual posttranslational modifications will be possible with previously impossible specificity. Finally, the link of today's high throughput recombinant antibody generation to a knock down phenotype is now possible with a single cloning step. It can therefore be expected that we will see a much quicker growth of the number of

  5. Synthesis, characterization and optical properties of NH4Dy(PO3)4

    NASA Astrophysics Data System (ADS)

    Chemingui, S.; Ferhi, M.; Horchani-Naifer, K.; Férid, M.

    2014-09-01

    Polycrystalline powders of NH4Dy(PO3)4 polyphosphate have been grown by the flux method. This compound was found to be isotopic with NH4Ce(PO3)4 and RbHo(PO3)4. It crystallizes in the monoclinic space group P21/n with unit cell parameters a=10.474(6) Å, b=9.011(4) Å, c=10.947(7) Å and β=106.64(3)°. The title compound has been transformed to triphosphate Dy(PO3)3 after calcination at 800 °C. Powder X-ray diffraction, infrared and Raman spectroscopies and the differential thermal analysis have been used to identify these materials. The spectroscopic properties have been investigated through absorption, excitation, emission spectra and decay curves of Dy3+ ion in both compounds at room temperature. The emission spectra show the characteristic emission bands of Dy3+ in the two compounds, before and after calcination. The integrated emission intensity ratios of the yellow to blue (IY/IB) transitions and the chromaticity properties have been determined from emission spectra. The decay curves are found to be double-exponential. The non-exponential behavior of the decay rates was related to the resonant energy transfer as well as cross-relaxation between the donor and acceptor Dy3+ ions. The determined properties have been discussed as function of crystal structure of both compounds. They reveal that NH4Dy(PO3)4 is promising for white light generation but Dy(PO3)3 is potential candidates in field emission display (FED) and plasma display panel (PDP) devices.

  6. Facile synthesis, structural characterization, and photoluminescence mechanism of Dy3+ doped YVO4 and Ca2+ co-doped YVO4:Dy3+ nano-lattices

    NASA Astrophysics Data System (ADS)

    Dhiren Meetei, Sanoujam; Deben Singh, Mutum; Dorendrajit Singh, Shougaijam

    2014-05-01

    Light plays a vital role in the evolution of life. From sunlight to candle-light and then to other form of lighting devices, human beings are utilizing light since time immemorial. Lighting devices such as conventional incandescent lamp and fluorescent lamp have been replaced by Light Emitting Diodes (LEDs) for the later is cheap, durable, etc. Now-a-days, phosphor converted LEDs have been burning issues in the fabrication of lighting devices. Especially, lanthanide ion(s) doped phosphors are of great interest for the same. However, doped phosphors have a limitation of luminescence quenching, i.e., instead of increasing luminescence on increasing dopant concentration, the luminescence decreases. Therefore, it must be rectified by one or other means so as to get maximum desirable intensity for uses in display or lighting devices. In the present work, YVO4:Dy3+ and YVO4:Dy3+/Ca2+ nano-lattices are synthesized by a facile technique. Structural characterizations such as x-ray diffraction, SEM, TEM, HRTEM, and Selected Area Electron Diffraction (SAED) of the samples are reported. Photoluminescence (PL) excitation and emission, enhanced mechanism, and lifetime are thoroughly discussed. PL intensity of the quenched YVO4:Dy3+ is made increased up to 432.63% by Ca2+ co-doping. Role of the Ca2+ on the luminescence enhanced mechanism of YVO4:Dy3+/Ca2+ is elucidated.

  7. Synthesis, characterization and luminescence behavior of ZrO2:Eu3+, Dy3+ with variable concentration of Eu and Dy doped Phosphor

    NASA Astrophysics Data System (ADS)

    Kaur, Jagjeet; Parganiha, Yogita; Dubey, Vikas; Singh, Deepti; Chandrakar, Deepika

    2014-09-01

    The present paper reports thermoluminescence (TL) glow curves and photoluminescence (PL) studies of europium, dysprosium co-doped zirconia (ZrO2:Eu3+, Dy3+). The sample were prepared by the solid state method with variable concentration of Eu (0.5-2 mol%) and Dy (0.5-2 mol%); thereafter, the TL glow curves were recorded for different doses of UV exposure at a heating rate of 6.7 °C s-1. The kinetic parameters activation energy E, the order of kinetics b, and the frequency factor “s” of synthesized phosphors of ZrO2:Eu3+, Dy3+ have been calculated by using a peak shape method. The sample was characterized by XRD (X-ray diffraction), SEM (scanning electron microscope) and FTIR (Fourier transform infrared spectroscopy). Effect of Eu and Dy concentration of PL and TL studies are also interpreted. Here the photoluminescence excitation and emission spectra were found at 307 and 395 nm and 594, 612 and 627 nm range respectively. The present phosphor acts as a single host for red emission display devices as well as may be used for thermoluminescence dosimetric material under UV exposure. Commission Internationale de l'éclairage co-ordinate of this nanophosphor (0.32, 0.34) is closed to that of the ideal white light (0.33, 0.33). Correlated color temperature of the white light (5894 K) is within the range of vertical daylight.

  8. High current DyBCO-ROEBEL Assembled Coated Conductor (RACC)

    NASA Astrophysics Data System (ADS)

    Goldacker, W.; Nast, R.; Kotzyba, G.; Schlachter, S. I.; Frank, A.; Ringsdorf, B.; Schmidt, C.; Komarek, P.

    2006-06-01

    Low AC loss high transport current HTS cables (>1 kA) are required for application in transformers, generators and are considered for future generations of fusion reactors coils. 2G coated conductors are suitable candidates for high field application at quite high operation temperatures of 50-77 K, which is crucial precondition for economical cooling costs. As a feasibility study we present the first ROEBEL bar cable of approx. 35 cm length made from industrial DyBCO coated conductor (THEVA GmbH, Germany). Meander shaped ROEBEL strands of 4 mm width with a twist pitch of 180 mm were cut from 10 mm wide CC tapes using a specially designed tool. The strands carried in average 157 Amps/cm-width DC and were assembled to a subcable with 5 strands and a final cable with 16 strands. The 5 strand cable was tested and carried a transport current of >300 Amps DC at 77 K, equivalent to the sum of the individual strand transport critical currents. The 16 strand cable carried 500 A limited through heating effects and non sufficient stabilisation and current sharing. A pulse current load indicated a current carrying potential of >1 kA for the 16 strand cable.

  9. Synthesis, characterization and optical properties of NH{sub 4}Dy(PO{sub 3}){sub 4}

    SciTech Connect

    Chemingui, S.; Ferhi, M. Horchani-Naifer, K.; Férid, M.

    2014-09-15

    Polycrystalline powders of NH{sub 4}Dy(PO{sub 3}){sub 4} polyphosphate have been grown by the flux method. This compound was found to be isotopic with NH{sub 4}Ce(PO{sub 3}){sub 4} and RbHo(PO{sub 3}){sub 4}. It crystallizes in the monoclinic space group P2{sub 1/n} with unit cell parameters a=10.474(6) Å, b=9.011(4) Å, c=10.947(7) Å and β=106.64(3)°. The title compound has been transformed to triphosphate Dy(PO{sub 3}){sub 3} after calcination at 800 °C. Powder X-ray diffraction, infrared and Raman spectroscopies and the differential thermal analysis have been used to identify these materials. The spectroscopic properties have been investigated through absorption, excitation, emission spectra and decay curves of Dy{sup 3+} ion in both compounds at room temperature. The emission spectra show the characteristic emission bands of Dy{sup 3+} in the two compounds, before and after calcination. The integrated emission intensity ratios of the yellow to blue (I{sub Y}/I{sub B}) transitions and the chromaticity properties have been determined from emission spectra. The decay curves are found to be double-exponential. The non-exponential behavior of the decay rates was related to the resonant energy transfer as well as cross-relaxation between the donor and acceptor Dy{sup 3+} ions. The determined properties have been discussed as function of crystal structure of both compounds. They reveal that NH{sub 4}Dy(PO{sub 3}){sub 4} is promising for white light generation but Dy(PO{sub 3}){sub 3} is potential candidates in field emission display (FED) and plasma display panel (PDP) devices. - Graphical abstract: The CIE color coordinate diagrams showing the chromatic coordinates of Dy{sup 3+} luminescence in NH{sub 4}Dy(PO{sub 3}){sub 4} and Dy(PO{sub 3}){sub 3}. - Highlights: • The polycrystalline powders of NH{sub 4}Dy(PO{sub 3}){sub 4} and Dy(PO{sub 3}){sub 3} are synthesized. • The obtained powders are characterized. • The spectroscopic properties of Dy{sup 3+} ion

  10. Mechanisms of oestrogen receptor (ER) gene regulation in breast cancer.

    PubMed

    Carroll, J S

    2016-07-01

    Most breast cancers are driven by a transcription factor called oestrogen receptor (ER). Understanding the mechanisms of ER activity in breast cancer has been a major research interest and recent genomic advances have revealed extraordinary insights into how ER mediates gene transcription and what occurs during endocrine resistance. This review discusses our current understanding on ER activity, with an emphasis on several evolving, but important areas of ER biology. PMID:26884552

  11. Heterometallic Cu(II)-Dy(III) Clusters of Different Nuclearities with Slow Magnetic Relaxation.

    PubMed

    Modak, Ritwik; Sikdar, Yeasin; Cosquer, Goulven; Chatterjee, Sudipta; Yamashita, Masahiro; Goswami, Sanchita

    2016-01-19

    The synthesis, structures, and magnetic properties of two heterometallic Cu(II)-Dy(III) clusters are reported. The first structural motif displays a pentanuclear Cu(II)4Dy(III) core, while the second one reveals a nonanuclear Cu(II)6Dy(III)3 core. We employed o-vanillin-based Schiff base ligands combining o-vanillin with 3-amino-1-propanol, H2vap, (2-[(3-hydroxy-propylimino)-methyl]-6-methoxy-phenol), and 2-aminoethanol, H2vae, (2-[(3-hydroxy-ethylimino)-methyl]-6-methoxy-phenol). The differing nuclearities of the two clusters stem from the choice of imino alcohol arm in the Schiff bases, H2vap and H2vae. This work is aimed at broadening the diversity of Cu(II)-Dy(III) clusters and to perceive the consequence of changing the length of the alcohol arm on the nuclearity of the cluster, providing valuable insight into promising future synthetic directions. The underlying topological entity of the pentanuclear Cu4Dy cluster is reported for the first time. The investigation of magnetic behaviors of 1 and 2 below 2 K reveals slow magnetic relaxation with a significant influence coming from the variation of the alcohol arm affecting the nature of magnetic interactions. PMID:26702645

  12. Size-dependent structure and magnetic properties of DyMnO{sub 3} nanoparticles

    SciTech Connect

    Cai, Xuan; Shi, Lei Zhou, Shiming; Zhao, Jiyin; Guo, Yuqiao; Wang, Cailin

    2014-09-14

    The structure and magnetic properties of orthorhombic DyMnO{sub 3} nanoparticles with different particle sizes are investigated in this paper. With decreasing particle size, all the lattice parameters a, b, and c gradually decrease, whereas the orthorhombic distortion increases. Magnetic measurements reveal that the antiferromagnetic interaction of Mn ions is weakened due to the decrease in Mn-O-Mn bond angle. Above a critical field H*, DyMnO{sub 3} undergoes a field-induced metamagnetic transition at 4 K, which is related to the spin reversal of Dy moments. The critical field H* increases monotonically with size reduction, indicating an enhancement of the antiferromagnetic interaction of Dy ions due to the decreased distance between rare earth ions. The magnetization at 4 K and 5 T, i.e., M(4 K, 5 T) shows a non-monotonic variation with particle size d, i.e., M(4 K, 5 T) initially increases with size reduction but decreases again for d < 68 nm. A modified core-shell model, in which the ferromagnetic ordering (Dy magnetic structure) and antiferromagnetic ordering (Mn magnetic structure) coexist in the core, is proposed to explain this behavior.

  13. Two new Dy3 triangles with trinuclear circular helicates and their single-molecule magnet behavior.

    PubMed

    Lin, Shuang-Yan; Zhao, Lang; Guo, Yun-Nan; Zhang, Peng; Guo, Yang; Tang, Jinkui

    2012-10-15

    Self-assembly of polydentate Schiff base 2,6-diformyl-4-methylphenol di(benzoy1hydrazone) (H(3)L), with dysprosium thiocyanate and sodium azide, affords two novel trinuclear triangular circular helicate dysprosium(III) complexes, [Dy(3)(μ(3)-OCH(3))(2)(HL)(3)(SCN)]·4CH(3)OH·2CH(3)CN·2H(2)O (1) or [Dy(3)(μ(3)-N(3))(μ(3)-OH)(H(2)L)(3)(SCN)(3)](SCN)·3CH(3)OH·H(2)O (2), depending on the presence or absence of base. Single-crystal X-ray analyses show that two μ(3)-methoxy oxygens cap the Dy(3) triangle in complex 1 and that one μ(3)-OH and one μ(3)-N(3)(-) cap the Dy(3) triangle of complex 2, representing the first example of a μ(3)-N(3)(-)-capped lanthanide complex reported to date. Ac susceptibility measurements reveal that multiple relaxation processes and the onset of slow magnetization relaxation occur for complex 1 and 2, respectively. Theoretical calculations are required to elucidate the underlying mechanism; however, the different magnetic anisotropy of the respective structures, which is dictated by the coordination environment of Dy(III) ions and structural parameters of the triangles, is mostly responsible for the distinctive relaxation dynamics observed. PMID:22510150

  14. Luminescence studies on SrMgAl 10O 17:Eu, Dy phosphor crystals

    NASA Astrophysics Data System (ADS)

    Wanjun, Tang; Donghua, Chen; Ming, Wu

    2009-02-01

    Using urea as fuel, SrMgAl 10O 17:Eu, Dy phosphor was prepared by a combustion method. Its luminescence properties under ultraviolet (UV) excitation were investigated. Pure SrMgAl 10O 17 phase was formed by urea-nitrate solution combustion synthesis at 550 °C. The results indicated that the emission spectra of SrMgAl 10O 17:Eu, Dy has one main peak at 460 nm and one shoulder peak near 516 nm, which are ascribed to two different types of luminescent Eu 2+ centers existing in the SrMgAl 10O 17 matrix crystal. The blue luminescence emission of SrMgAl 10O 17:Eu phosphors was improved under UV excitation by codoping Dy 3+ ions. The SrMgAl 10O 17:Eu phosphors showed green afterglow ( λ=516 nm) when Dy 3+ ions were doped. Dy 3+ ions not only successfully play the role of sensitizer for energy transfer in the system, but also act as trap levels and capture the free holes in the spinel blocks.

  15. Competing magnetic phases and field-induced dynamics in DyRuAsO

    NASA Astrophysics Data System (ADS)

    McGuire, Michael A.; Garlea, V. Ovidiu; May, Andrew F.; Sales, Brian C.

    2014-07-01

    Analysis of neutron diffraction, dc magnetization, ac magnetic susceptibility, heat capacity, and electrical resistivity for DyRuAsO in an applied magnetic field are presented at temperatures near and below those at which the structural distortion (TS=25 K) and subsequent magnetic ordering (TN=10.5 K) take place. Powder neutron diffraction is used to determine the antiferromagnetic order of Dy moments of magnitude 7.6(1)μB in the absence of a magnetic field, and demonstrate the reorientation of the moments into a ferromagnetic configuration upon application of a magnetic field. Dy magnetism is identified as the driving force for the structural distortion. The magnetic structure of analogous TbRuAsO is also reported. Competition between the two magnetically ordered states in DyRuAsO is found to produce unusual physical properties in applied magnetic fields at low temperature. An additional phase transition near T*=3 K is observed in heat capacity and other properties in fields ≳3 T. Magnetic fields of this magnitude also induce spin-glass-like behavior including thermal and magnetic hysteresis, divergence of zero-field-cooled and field-cooled magnetization, frequency dependent anomalies in ac magnetic susceptibility, and slow relaxation of the magnetization. This is remarkable since DyRuAsO is a stoichiometric material with no disorder detected by neutron diffraction, and suggests analogies with spin-ice compounds and related materials with strong geometric frustration.

  16. Deficiency of merosin in dystrophic dy mouse homologue of congenital muscular dystrophy

    SciTech Connect

    Sunada, Y.; Campbell, K.P.; Bernier, S.M.

    1994-09-01

    Merosin (laminin M chain) is the predominant laminin isoform in the basal lamina of striated muscle and peripheral nerve and is a native ligand for {alpha}-dystroglycan, a novel laminin receptor. Merosin is linked to the subsarcolemmal actin cytoskeleton via the dystrophin-glycoprotein complex (DGC), which plays an important role for maintenance of normal muscle function. We have mapped the mouse merosin gene, Lamm, to the region containing the dystrophia muscularis (dy) locus on chromosome 10. This suggested the possibility that a mutation in the merosin gene could be responsible for the dy mouse, an animal model for autosomal recessive muscular dystrophy, and prompted us to test this hypothesis. We analyzed the status of merosin expression in dy mouse by immunofluorescence and immunoblotting. In dy mouse skeletal and cardiac muscle and peripheral nerve, merosin was reduced greater than 90% as compared to control mice. However, the expression of laminin B1/B2 chains and collagen type IV was smaller to that in control mice. These findings strongly suggest that merosin deficiency may be the primary defect in the dy mouse. Furthermore, we have identified two patients afflicted with congenital muscular dystrophy with merosin deficiency, providing the basis for future studies of molecular pathogenesis and gene therapy.

  17. Photoluminescence Properties and Energy Transfer in a Novel Yellow Emitting Phosphor GdTaO4: Dy3+.

    PubMed

    Zhang, Hijuan; Tan, Xinyu; Wang, Yuhua

    2016-04-01

    The phosphor Dy3+ doped M type gadolinium orthotantalate GdTaO4 was prepared successfully by traditional solid state reaction and the photoluminescence of GdTaO4: xDy3+ (0.01 ≤ x ≤ 0.10) has been investigated under ultraviolet and vacuum ultraviolet excitation. In the excitation spectra of GdTaO4: Dy3+, the overlap appears between the host lattice excitation, the excitation lines of Gd3+ and the f-f transitions of Dy3+, which indicates that the energy transfer could occur from the host to the Dy3+ ions. In the emission spectra of the samples, the intense emissions of Dy3+ have been expectably revealed both upon excitation at 365 nm and 147 nm. And the chromaticity coordinates of GdTaO4: xDy3+ have been correspondingly calculated. The results indicate that GdTaO4: Dy3+ would be a novel yellow emitting phosphor applied in light emitting diodes (LEDs), plasma display panels (PDPs) and mercury-free fluorescent tubes. PMID:27451754

  18. X-ray induced fluorescence measurement of segregation in a DyI3-Hg metal-halide lamp.

    SciTech Connect

    Nimalasuriya , T.; Curry, J. J.; Sansonetti, C. J.; Ridderhof, E. J.; Shastri, S. D.; Filkweert, A. J.; Stoffels, W. W.; Haverlag, M.; van der Mullen, J. J.; Eindhoven Univ. of Technology; NIST

    2007-05-07

    Segregation of elemental Dy in a DyI{sub 3}-Hg metal-halide high-intensity discharge lamp has been observed with x-ray induced fluorescence. Significant radial and axial Dy segregation are seen, with the axial segregation characterized by a Fischer parameter value of {lambda} = 0.215 {+-} 0.002 mm{sup -1}. This is within 7% of the value ({lambda} = 0.20 {+-} 0.01 mm{sup -1}) obtained by Flikweert et al based on laser absorption by neutral Dy atoms. Elemental I is seen to exhibit considerably less axial and radial segregation. Some aspects of the observed radial segregation are compatible with a simplified fluid picture describing two main transition regions in the radial coordinate. The first transition occurs in the region where DyI{sub 3} molecules are in equilibrium with neutral Dy atoms. The second transition occurs where neutral Dy atoms are in equilibrium with ionized Dy. These measurements are part of a larger study on segregation in metal-halide lamps under a variety of conditions.

  19. Thermoluminescent response of CaSO4:Dy+PTFE induced by X-ray beams.

    PubMed

    Hernández, L; Rivera, T; Jimenez, Y; Alvarez, R; Zeferino, J; Vázquez, A; Azorín, J

    2012-07-01

    The aim of the present work was to evaluate the feasibility of the utilization of CaSO4:Dy pellets for X-ray measurements in a general radiology department. Thermoluminescence (TL) response of CaSO4:Dy+PTFE was compared to the TL response of commercial LiF:Mg,Ti (TLD-100) samples. TL pellets were exposed to X-ray beam from X-ray machine CMR for clinical diagnosis purpose. The calibration curve of CaSO4:Dy+PTFE was obtained and it showed a linear response as a function of absorbed dose in air at the studied dose interval. Despite this fact, this material can be used for X-ray beams measurements if appropriate calibration procedures are performed. PMID:22182627

  20. Discrimination of reactively-dyed cotton fibres with thin layer chromatography and UV microspectrophotometry.

    PubMed

    De Wael, K; Van Dijck, K; Gason, F

    2015-12-01

    Reactively-dyed black, navy blue and medium red cotton samples showing metamerism under fluorescent tube illumination were examined. Optical microscopy (bright field, polarization and fluorescence microscopy) was used, followed by microspectrometry in the visible range (MSP Vis), to differentiate the samples in each block of colours. Additionally, the non-discriminated samples were subjected both to microspectrophotometry in the UV-range (MSP UV) and to enzymatic digestion followed by high performance thin layer chromatography (HPTLC) on the digests. While it was found that both methods may potentially result in higher discrimination, preparation of reactively-dyed cotton for HPTLC was found to be a very tedious and time-consuming step and HPTLC only led to a better discrimination than MSP UV for the red cotton samples. The results suggest that in order to increase the discrimination for reactively-dyed cotton fibres, measurement of the UV absorption spectrum (MSP UV) is preferred over HPTLC. PMID:26654077

  1. Quadrupole effects in tetragonal crystals PrCu₂Si₂ and DyCu₂Si₂.

    PubMed

    Mitsumoto, Keisuke; Goto, Saori; Nemoto, Yuichi; Akatsu, Mitsuhiro; Goto, Terutaka; Dung, Nguyen D; Matsuda, Tatsuma D; Haga, Yoshinori; Takeuchi, Tetsuya; Sugiyama, Kiyohiro; Settai, Rikio; Onuki, Yoshichika

    2013-07-24

    We have investigated quadrupole effects in tetragonal crystals of PrCu2Si2 and DyCu2Si2 by means of low-temperature ultrasonic measurements. The elastic constant C44 of PrCu2Si2 exhibits pronounced softening below 70 K down to a Néel temperature TN = 20 K, which is described in terms of a quadrupole susceptibility for a Γ5 doublet ground state and a Γ3 singlet first excited state located at 15.6 K in the crystalline electric field scheme. The C44 and C66 of DyCu2Si2 also show softening below 70 K down to TN1 = 9.7 K. A low-lying pseudo-sextet state consisting of three Kramers doublets of Γ6⊕2Γ7 brings about softening of C44 and C66 in DyCu2Si2. PMID:23803419

  2. Optical properties of Dy3+ ion in PbF2 laser crystal

    NASA Astrophysics Data System (ADS)

    Chen, G. Z.; Yin, J. G.; Zhang, L. H.; He, M. Z.; Ma, E.; Ning, K. J.; Zhang, P. X.; Liu, Y. C.; Hang, Y.

    2013-11-01

    High-quality Dy:PbF2 crystal is grown by the Bridgman method in a nonvacuum atmosphere. By measuring the area under absorption bands, the experimental oscillator strengths are determined. The Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4, 6) are evaluated by the least-squares fit method. These phenomenological parameters are used to predict radiative transition probabilities, radiative lifetime and branching ratios for various excited levels of the Dy3+:PbF2 crystal. Photoluminescence spectra and lifetime of 6H13/2 levels of the Dy3+ ions have been measured. The laser transitions with most potential are identified and the utility of the PbF2 crystal as laser active material is discussed.

  3. Large rotating magnetocaloric effect in the orthorhombic DyMnO3 single crystal

    NASA Astrophysics Data System (ADS)

    Balli, M.; Mansouri, S.; Jandl, S.; Fournier, P.; Dimitrov, D. Z.

    2016-07-01

    A large magnetocaloric effect can be obtained around TN, Dy ̴8 K simply by spinning the orthorhombic DyMnO3 single crystal within the cb-plane in a constant magnetic field, instead of the standard magnetization-demagnetization process. Under 7 T, the maximum rotating entropy change (-ΔSR, cb) and the associated adiabatic temperature change (ΔTad, cb) are 16.3 J/kg K and 11 K, respectively. The corresponding refrigerant capacity is 440 J/kg, with no thermal and field hysteresis losses. Our findings show that the orthorhombic DyMnO3 could be used as a good refrigerant in more compact and efficient cryomagnetocaloric refrigerators.

  4. Electrospun Dy-doped SrFe12O19 nanofibers: microstructure and magnetic properties

    NASA Astrophysics Data System (ADS)

    Pan, L. N.; Gu, F. M.; Cao, D. R.; Jing, P. P.; Li, J. N.; Wang, J. B.; Liu, Q. F.

    2016-06-01

    SrDy x Fe12- x O19 ( x ≤ 0.08) nanofibers have been synthesized by the electrospinning method followed by calcinations process. The partial substitution of rare earth ions Dy3+ (10.5 μ B of magnetic moments) mainly occupying 12 k sublattice sites in the SrFe12O19 crystal structure is investigated and discussed in this work. An enhanced coercivity of 7155 Oe has been obtained when the doped content reached to 0.08 at a relative low calcination temperature of 800 °C. As a result, we believe the synthesized SrDy x Fe12- x O19 nanofibers can potentially be useful in high-density recording media as well as permanent magnets.

  5. Magnetic separation of Dy(III) ions from homogeneous aqueous solutions

    SciTech Connect

    Pulko, B. Yang, X.; Lei, Z.; Odenbach, S.; Eckert, K.

    2014-12-08

    The possibility to enrich paramagnetic dysprosium(III) ions in a magnetic field gradient is proved by means of interferometry, which may open the route for a magnetic separation of rare earth ions from aqueous solutions. The separation dynamics are studied for three different concentrations of DyCl{sub 3} and compared with those found recently in a sulphate solution of the 3d ion Mn(II). In view of the similar-sized hydration spheres for Dy(III) and Mn(II), the slower separation dynamics in DyCl{sub 3} is attributed to both a higher densification coefficient and the strong impact of Brownian motion due to the absence of ion-pair clusters.

  6. Structural and optical characterization of DyAlO3 perovskite powders obtained by combustion synthesis

    NASA Astrophysics Data System (ADS)

    Saji S., K.; Raju, K.; Wariar, P. R. S.

    2016-05-01

    Phase pure Dysprosium monoaluminate has been prepared from Dysprosium oxide and Aluminium nitrate by auto-ignition citrate complex combustion process. The phase formation has been investigated using X-ray diffraction analysis (XRD), Thermo-Gravimetric/Differential Thermal Analysis (TGA/DTA) and Fourier Transform Infrared (FT-IR) spectroscopy analysis. X-ray diffraction analysis (XRD) revealed that DyAlO3 has an orthorhombic perovskite structure. From Transmission Electron Microscopy (TEM) studies, average particle-size has been found to be as low as 45 nm. The absorption spectrum of the DyAlO3 nanoparticles shows characteristic absorption bands of Dy atom. The optical band gap of the material was found to be 5.15eV, which corresponds to direct allowed transitions.

  7. Positron annihilation studies of Eu and Dy doped α'-Sr2SiO4

    NASA Astrophysics Data System (ADS)

    Gupta, S. K.; Sudarshan, K.; Sharma, S. K.; Pujari, P. K.; Natarajan, V.

    2015-06-01

    Sr2SiO4 is an important inorganic host for lanthanide doped white light emitting diodes (LEDs). Strontium silicate (Sr2SiO4) samples doped with 1.0 mol% of Eu3+ and Dy3+ content were prepared via sol-gel route and characterized by X-ray diffraction (XRD), Raman spectroscopy and positron annihilation spectroscopy (PAS). The concentration of the dopant ion and the temperature of annealing were optimized for maximum luminescence intensity. The positron annihilation lifetime and coincidence Doppler broadening (CDB) measurements indicated that the local environment around the positron annihilation site is different in Eu+3 doped and Dy+3 doped samples. The results could be explained based on the different local site occupancy of Eu+3 and Dy+3 in the matrix.

  8. Luminescence properties of Ce 3+-Dy 3+ codoped aluminium oxide films

    NASA Astrophysics Data System (ADS)

    Martínez-Martínez, R.; Rivera, S.; Yescas-Mendoza, E.; Álvarez, E.; Falcony, C.; Caldiño, U.

    2011-06-01

    Photoluminescence properties of CeCl 3 and DyCl 3 codoped aluminium oxide films deposited by the ultrasonic spray pyrolysis technique were characterized by excitation, emission and decay time spectroscopy. When excited by ultraviolet radiation the films emit a combination of blue and yellow wavelengths through an efficient energy transfer from Ce 3+ to Dy 3+ ions (up to around 77%). From spectroscopic data it is inferred that such energy transfer is nonradiative in nature taking place between Ce 3+ and Dy 3+ clusters through a short-range interaction mechanism. In the Ce 3+ doped single film the chromaticity coordinates are in the purplish blue region, whereas that in the cerium and dysprosium codoped films the coordinates move toward the white light emission region.

  9. Magnetization and magnetic entropy of Dy2Ti2O7

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1974-01-01

    Isothermal measurements of the magnetic entropy, magnetization, and differential susceptibility of Dy2Ti2O7 have been made. Absolute values of magnetic entropy have been determined as a function of applied magnetic field for several temperatures in the range 2-20 K, and several isofield lines in the magnetic entropy-temperature plane have been determined. Magnetization measurements, which extended into the saturation region, yield a powder-average magnetic moment of about 4.7 Bohr magnetons per ion. A van Vleck contribution to M was also observed. The results are consistent with the assumption of a nearly pure Jz equals + or - 15/2 ground-state Kramers doublet for the Dy(+++) ion. Comments on the suitability of Dy2Ti2O7 for use in a magnetic refrigerator cycling between 4.2 and 20 K are included.

  10. Specific features of optical absorption in rare-earth orthoaluminate DyAlO3

    NASA Astrophysics Data System (ADS)

    Valiev, U. V.; Gruber, J. B.; Rakhimov, Sh. A.

    2003-04-01

    Polarization spectra of optical absorption of the 4 f-4 f transition 6 H 15/2 → 6 F 3/2 in the rare-earth orthoaluminate DyAlO3 are theoretically and experimentally studied at the temperature T=78 K. It is shown that the nontrivial character of the anisotropy of the polarization absorption spectra at low temperatures can be explained by the J-J mixing of excited multiplets of the 4 f 9 configuration of Dy3+ ions in a low-symmetry crystal field of the orthoaluminate structure. The energy and wave functions of the Stark sublevels within the excited 6 F 5/2 multiplet in the 4 f 9 configuration of the Dy3+ rare-earth ion in the crystal field of C s symmetry are numerically calculated.

  11. Optical emission spectroscopy of metal-halide lamps: Radially resolved atomic state distribution functions of Dy and Hg

    SciTech Connect

    Nimalasuriya, T.; Flikweert, A.J.; Stoffels, W.W.; Haverlag, M.; Mullen, J.J.A.M. van der; Pupat, N.B.M.

    2006-03-01

    Absolute line intensity measurements are performed on a metal-halide lamp. Several transitions of atomic and ionic Dy and atomic Hg are measured at different radial positions from which we obtain absolute atomic and ionic Dy intensity profiles. From these profiles we construct the radially resolved atomic state distribution function (ASDF) of the atomic and ionic Dy and the atomic Hg. From these ASDFs several quantities are determined as functions of radial position, such as the (excitation) temperature, the ion ratio Hg{sup +}/Dy{sup +}, the electron density, the ground state, and the total density of Dy atoms and ions. Moreover, these ASDFs give us insight about the departure from equilibrium. The measurements show a hollow density profile for the atoms and the ionization of atoms in the center. In the outer parts of the lamp molecules dominate.

  12. Optical emission spectroscopy of metal-halide lamps: Radially resolved atomic state distribution functions of Dy and Hg

    NASA Astrophysics Data System (ADS)

    Nimalasuriya, T.; Flikweert, A. J.; Stoffels, W. W.; Haverlag, M.; van der Mullen, J. J. A. M.; Pupat, N. B. M.

    2006-03-01

    Absolute line intensity measurements are performed on a metal-halide lamp. Several transitions of atomic and ionic Dy and atomic Hg are measured at different radial positions from which we obtain absolute atomic and ionic Dy intensity profiles. From these profiles we construct the radially resolved atomic state distribution function (ASDF) of the atomic and ionic Dy and the atomic Hg. From these ASDFs several quantities are determined as functions of radial position, such as the (excitation) temperature, the ion ratio Hg+/Dy+, the electron density, the ground state, and the total density of Dy atoms and ions. Moreover, these ASDFs give us insight about the departure from equilibrium. The measurements show a hollow density profile for the atoms and the ionization of atoms in the center. In the outer parts of the lamp molecules dominate.

  13. Investigation on photoluminescence properties and defect chemistry of GdAlO3:Dy3+ Ba2+ phosphors

    NASA Astrophysics Data System (ADS)

    Selvalakshmi, Thangaraj; Sellaiyan, Selvakumar; Uedono, Akira; Semba, Takaaki; Bose, Arumugam Chandra

    2016-08-01

    GdAlO3:Dy3+ Ba2+ phosphors are synthesized by citrate-based sol-gel method. Photoluminescence and positron annihilation studies are used to investigate the emission and defect chemistry of the phosphors respectively. The strong yellow (Dy3+) emission properties of phosphors are discussed for various concentrations of Dy3+ ions. Upon the addition of Ba2+ ion, an enhancement in emission intensity is observed due to the lattice distortions around Dy3+ ion. The positron studies indicate the presence of defects at crystallite boundaries, vacancy clusters and large voids in the materials. The influence of Ba2+ ion on the photoluminescence and lattice distortion around Dy3+ is also explored.

  14. White light simulation and luminescence studies on Dy3+ doped Zinc borophosphate glasses

    NASA Astrophysics Data System (ADS)

    Vijayakumar, R.; Venkataiah, G.; Marimuthu, K.

    2015-01-01

    The Dy3+ doped Zinc borophosphate glasses with the chemical composition (79-x)B2O3+xP2O5+10Li2O+10ZnO+1Dy2O3 (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 Dy3+ 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 Dy3+ ions. The Q, R0 and CDA values of the prepared Dy3+ doped glasses were obtained from the IH model and the results were discussed and compared with the reported literature.

  15. ARM CLASIC ER2 CRS/EDOP

    SciTech Connect

    Gerald Heymsfield

    2010-12-20

    Data was taken with the NASA ER-2 aircraft with the Cloud Radar System and other instruments in conjunction with the DOE ARM CLASIC field campaign. The flights were near the SGP site in north Central Oklahoma and targeted small developing convection. The CRS is a 94 GHz nadir pointing Doppler radar. Also on board the ER-2 was the Cloud Physics Lidar (CPL). Seven science flights were conducted but the weather conditions did not cooperate in that there was neither developing convection, or there was heavy rain.

  16. Dosimetry of fast neutron beams using CaSO 4:Dy (TLD-900) pellets

    NASA Astrophysics Data System (ADS)

    Pradhan, A. S.; Rassow, J.; Meissner, P.

    1985-05-01

    This paper describes the use of commercially avialable CaSO 4:Dy (TLD-900) pellets for the measurement of absorbed doses of fast neutrons and gamma rays in mixed fields with one single detector. The gamma ray absorbed doses could be estimated by recording the thermoluminiscence (TL) induced during the neutron beam irradiations, whereas the fast neutron absorbed doses were measured by employing a post-irradiation TL accumulation due to activation of sulphur by the threshold nuclear reaction 32S(n, p) 32P in CaSO 4:Dy.

  17. Ab initio study of double perovskites Ba2DySbO6

    NASA Astrophysics Data System (ADS)

    Jha, Dhiraj Kumar; Mandal, Golak; Ray, Chandan; Himanshu, A. K.; Singh, B. K.; Kumar, Uday; Choudhary, B. K.

    2016-05-01

    First principle study of the electronic band structure of Ba2DySbO6 synthesied by the solid state reaction technique have been performed within the framework of density function theory using WIEN2K. It has been shown in the absence of electron-electron interaction (U=0), BaDySO6 behaves like a half-metal. Even in the presence of DFT+U, electron-electron interaction via the Hubbard term (from U = 0, 2.72e -7.02eV), it still shows half metals.

  18. Enhancement of spin relaxation in an FeDy2 Fe coordination cluster by magnetic fields.

    PubMed

    Peng, Guo; Mereacre, Valeriu; Kostakis, George E; Wolny, Juliusz A; Schünemann, Volker; Powell, Annie K

    2014-09-22

    Two [FeLn2 Fe(μ3 -OH)2 (teg)2 (N3 )2 (C6 H5 COO)4 ] compounds (where Ln=Y(III) and Dy(III) ; teg=triethylene glycol anion) have been synthesized and studied using SQUID and Mössbauer spectroscopy. The magnetic measurements on both compounds indicate dominant antiferromagnetic interactions between the metal centers. Analysis of the (57) Fe Mössbauer spectra complement the ac magnetic susceptibility measurements, which show how a static magnetic field can quench the slow relaxation of magnetization generated by the anisotropic Dy(III) ions. PMID:25197018

  19. High-pressure synthesis of a La orthosilicate and Nd, Gd, and Dy disilicates

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoyang; Fleet, Michael E.

    2002-11-01

    Several rare-earth silicates have been synthesized at 10 GPa and 1600-1700 °C: a La orthosilicate (La4Si3O12) with a defect Ba3(PO4)2-type, a new structure type (K) for Nd and Gd disilicates (Nd2Si2O7 and Gd2Si2O7) with a diorthosilicate structure, and a new structure type (L) for Dy disilicate (Dy2Si2O7) with a structure containing linear triple tetrahedral groups [Si3O10], but having one in six atoms distributed with 50% occupancy over two tetrahedral positions.

  20. THE HOT R CORONAE BOREALIS STAR DY CENTAURI IS A BINARY

    SciTech Connect

    Kameswara Rao, N.; Lambert, David L.; McArthur, Barbara; Garcia-Hernandez, D. A.; Woolf, Vincent M. E-mail: dll@astro.as.utexas.edu

    2012-11-20

    The remarkable hot R Coronae Borealis (RCB) star DY Cen is revealed to be the first and only binary system to be found among the RCB stars and their likely relatives, including the extreme helium stars and the hydrogen-deficient carbon stars. Radial velocity determinations from 1982 to 2010 have shown that DY Cen is a single-lined spectroscopic binary in an eccentric orbit with a period of 39.67 days. It is also one of the hottest and most H-rich member of the class of RCB stars. The system may have evolved from a common envelope to its current form.

  1. Homochiral mononuclear Dy-Schiff base complexes showing field-induced double magnetic relaxation processes.

    PubMed

    Ren, Min; Xu, Zhong-Li; Wang, Ting-Ting; Bao, Song-Song; Zheng, Ze-Hua; Zhang, Zai-Chao; Zheng, Li-Min

    2016-01-14

    A pair of enantiopure mononuclear dysprosium/salen-type complexes (Et3NH)[Dy((R,R)/(S,S)-3-NO2salcy)2] (/), where 3-NO2salcyH2 represents N,N'-(1,2-cyclohexanediylethylene)bis(3-nitrosalicylideneiminato), are reported. The enantiomer contains two crystallographically independent dysprosium(iii) ions, each chelated by two enantiopure 3-NO2salcy(2-) ligands forming a [DyN4O4] core. Detailed magnetic studies on compound reveal a field-induced dual magnetic relaxation behavior, originating from single ion anisotropy and intermolecular interactions, respectively. PMID:26621766

  2. Crystal field analysis of Dy and Tm implanted silicon for photonic and quantum technologies.

    PubMed

    Hughes, Mark A; Lourenço, Manon A; Carey, J David; Murdin, Ben; Homewood, Kevin P

    2014-12-01

    We report the lattice site and symmetry of optically active Dy3+ and Tm3+ implanted Si. Local symmetry was determined by fitting crystal field parameters (CFPs), corresponding to various common symmetries, to the ground state splitting determined by photoluminescence measurements. These CFP values were then used to calculate the splitting of every J manifold. We find that both Dy and Tm ions are in a Si substitution site with local tetragonal symmetry. Knowledge of rare-earth ion symmetry is important in maximising the number of optically active centres and for quantum technology applications where local symmetry can be used to control decoherence. PMID:25606863

  3. Evol and ProDy for bridging protein sequence evolution and structural dynamics

    PubMed Central

    Mao, Wenzhi; Liu, Ying; Chennubhotla, Chakra; Lezon, Timothy R.; Bahar, Ivet

    2014-01-01

    Correlations between sequence evolution and structural dynamics are of utmost importance in understanding the molecular mechanisms of function and their evolution. We have integrated Evol, a new package for fast and efficient comparative analysis of evolutionary patterns and conformational dynamics, into ProDy, a computational toolbox designed for inferring protein dynamics from experimental and theoretical data. Using information-theoretic approaches, Evol coanalyzes conservation and coevolution profiles extracted from multiple sequence alignments of protein families with their inferred dynamics. Availability and implementation: ProDy and Evol are open-source and freely available under MIT License from http://prody.csb.pitt.edu/. Contact: bahar@pitt.edu PMID:24849577

  4. Decay studies of the neutron-rich isotopes sup 168 Dy and sup 168 Ho sup g and the identification of the new isomer sup 168 Ho sup m

    SciTech Connect

    Chasteler, R.M.; Nitschke, J.M.; Firestone, R.B.; Vierinen, K.S.; Wilmarth, P.A. )

    1990-11-01

    Multinucleon transfer reactions between {sup 170}Er ions and {sup nat}W targets with on-line mass separation were used to produce neutron-rich {ital A}=168 isotopes. {beta} and {gamma} spectroscopy was used to study the decay of these activities. A new isomer of holmium, {sup 168}Ho{sup {ital m}}, was identified to decay by an isomeric transition with a half-life of 132(4) s. A decay scheme for the most neutron-rich {ital A}=168 isotope, 8.8(3)-min {sup 168}Dy, was determined. Also, a new {ital Q}{sub {beta}}{sup {minus}} value of 2.93(3) MeV for the decay of 3.0-min {sup 168}Ho{sup {ital g}} has been obtained.

  5. Heterometallic trinuclear {CoLn(III)} (Ln = Gd, Tb, Ho and Er) complexes in a bent geometry. Field-induced single-ion magnetic behavior of the Er(III) and Tb(III) analogues.

    PubMed

    Goura, Joydeb; Brambleby, Jamie; Topping, Craig V; Goddard, Paul A; Suriya Narayanan, Ramakirushnan; Bar, Arun Kumar; Chandrasekhar, Vadapalli

    2016-05-31

    Through the use of a multi-site compartmental ligand, 2-methoxy-6-[{2-(2-hydroxyethylamino)ethylimino}methyl]phenol (LH3), the family of heterometallic, trinuclear complexes of the formula [CoLn(L)2(μ-O2CCH3)2(H2O)3]·NO3·xMeOH·yH2O has been expanded beyond Ln = Dy(III) to include Gd(III) (), Tb(III) (), Ho(III) () and Er(III) () for , and (x = 1; y = 1) and for (x = 0; y = 2). The metallic core of these complexes consists of a (Co(III)-Ln(III)-Co(III)) motif bridged in a bent geometry resulting in six-coordinated distorted Co(III) octahedra and nine-coordinated Ln(III) monocapped square-antiprisms. The magnetic characterization of these compounds reveals the erbium and terbium analogues to display a field induced single-ion magnetic behavior similar to the dysprosium analogue but at lower temperatures. The energy barrier for the reversal of the magnetization of the CoTb(III) analogue is Ueff ≥ 15.6(4) K, while for the CoEr(III) analogue Ueff ≥ 9.9(8) K. The magnetic properties are discussed in terms of distortions of the 4f electron cloud. PMID:27180723

  6. 20 CFR 228.10 - Computation of the tier I annuity component for a widow(er), disabled widow(er), remarried widow...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Computation of the tier I annuity component for a widow(er), disabled widow(er), remarried widow(er), and a surviving divorced spouse. 228.10... component for a widow(er), disabled widow(er), remarried widow(er), and a surviving divorced spouse....

  7. 20 CFR 228.10 - Computation of the tier I annuity component for a widow(er), disabled widow(er), remarried widow...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Computation of the tier I annuity component for a widow(er), disabled widow(er), remarried widow(er), and a surviving divorced spouse. 228.10... component for a widow(er), disabled widow(er), remarried widow(er), and a surviving divorced spouse....

  8. 20 CFR 228.10 - Computation of the tier I annuity component for a widow(er), disabled widow(er), remarried widow...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Computation of the tier I annuity component for a widow(er), disabled widow(er), remarried widow(er), and a surviving divorced spouse. 228.10... component for a widow(er), disabled widow(er), remarried widow(er), and a surviving divorced spouse....

  9. 20 CFR 228.10 - Computation of the tier I annuity component for a widow(er), disabled widow(er), remarried widow...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Computation of the tier I annuity component for a widow(er), disabled widow(er), remarried widow(er), and a surviving divorced spouse. 228.10... component for a widow(er), disabled widow(er), remarried widow(er), and a surviving divorced spouse....

  10. 20 CFR 228.10 - Computation of the tier I annuity component for a widow(er), disabled widow(er), remarried widow...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Computation of the tier I annuity component for a widow(er), disabled widow(er), remarried widow(er), and a surviving divorced spouse. 228.10... component for a widow(er), disabled widow(er), remarried widow(er), and a surviving divorced spouse....

  11. Low temperature properties of some Er-rich intermetallic compounds

    SciTech Connect

    K.A. Gshneidner,jr; A.O. Pecharsky; L.Hale; V.K. Pecharsky

    2004-09-30

    The low temperature volumetric heat capacity ({approx}3.5 to 350 K) and magnetic susceptibility ({approx}4 to 320 K) of Er{sub 3}Rh, Er{sub 3}Ir, Er{sub 3}Pt, Er{sub 2}Al, and Er{sub 2}Sn have been measured. All of the compounds order antiferromagnetically (or ferrimagnetically), and most exhibit more than one magnetic ordering transition. The volumetric heat capacities in general are smaller than those of the prototype magnetic regenerator materials, except for Er{sub 3}Ir in the 12 to 14 K temperature range.

  12. Life or death by NFκB, Losartan promotes survival in dy2J/dy2J mouse of MDC1A

    PubMed Central

    Elbaz, M; Yanay, N; Laban, S; Rabie, M; Mitrani-Rosenbaum, S; Nevo, Y

    2015-01-01

    Inflammation and fibrosis are well-defined mechanisms involved in the pathogenesis of the incurable Laminin α2-deficient congenital muscular dystrophy (MDC1A), while apoptosis mechanism is barely discussed. Our previous study showed treatment with Losartan, an angiotensin II type I receptor antagonist, improved muscle strength and reduced fibrosis through transforming growth factor beta (TGF-β) and mitogen-activated protein kinases (MAPK) signaling inhibition in the dy2J/dy2J mouse model of MDC1A. Here we show for the first time that Losartan treatment up-regulates and shifts the nuclear factor kappa B (NFκB) signaling pathway to favor survival versus apoptosis/damage in this animal model. Losartan treatment was associated with significantly increased serum tumor necrosis factor alpha (TNF-α) level, p65 nuclei accumulation, and decreased muscle IκB-β protein level, indicating NFκB activation. Moreover, NFκB anti-apoptotic target genes TNF receptor-associated factor 1 (TRAF1), TNF receptor-associated factor 2 (TRAF2), cellular inhibitor of apoptosis (cIAP2), and Ferritin heavy chain (FTH1) were increased following Losartan treatment. Losartan induced protein expression toward a pro-survival profile as BCL-2 expression levels were increased and Caspase-3 expression levels were decreased. Muscle apoptosis reduction was further confirmed using terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) assay. Thus, along with TGF-β and MAPK signaling, NFκB serves as an important regulatory pathway which following Losartan treatment promotes survival in the dy2J/dy2J mouse model of MDC1A. PMID:25766329

  13. ER – the key to the highway

    PubMed Central

    Stefano, Giovanni; Hawes, Chris; Brandizzi, Federica

    2014-01-01

    The endoplasmic reticulum (ER) is the key organelle at the start of the secretory pathway and the list of its functions is continually growing. The ER organization as a tubular/cisternal network at the cortex of plant cells has recently been shown to be governed by the membrane tubulation proteins of the reticulon family working alongside plant atlastin homologues, members of the RHD3 group of proteins. Such a network has intimate connections with other organelles such as peroxisomes via peroxules, chloroplasts, Golgi bodies and at the cell cortex to the plasma membrane with cytoskeleton at so called “anchor/contact sites”. The ER network is by no means static displaying a range of different movements and acting as a sub-cellular highway supports the motility of organelles such as peroxisomes, mitochondria and Golgi bodies plus the transport of macromolecules such as viral movement proteins, nucleocapsid proteins and RNA. Here we highlight recent and exciting discoveries on the maintenance of the ER structure and its role on movement and biology of other organelles. PMID:25259957

  14. The QuEChERS revolution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The technique of QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) is only 7 years old, yet it is revolutionizing the manner in which multiresidue, multiclass pesticide analysis (and perhaps beyond) is performed. Columnist Ron Majors sits down with inventors Steve Lehotay and Michelangelo An...

  15. Creating Smart-er Cities: An Overview

    ERIC Educational Resources Information Center

    Allwinkle, Sam; Cruickshank, Peter

    2011-01-01

    The following offers an overview of what it means for cities to be "smart." It draws the supporting definitions and critical insights into smart cities from a series of papers presented at the 2009 Trans-national Conference on Creating Smart(er) Cities. What the papers all have in common is their desire to overcome the all too often…

  16. European Space Agency, ERS-1 program

    NASA Technical Reports Server (NTRS)

    Haskell, A.

    1983-01-01

    The objectives selected for ERS-1 which are primarily intended to facilitate the exploitation of coastal oceans, including ice infested waters, and to facilitate the development of improved global weather information through the provision of information on the weather conditions over the oceans of the word are outlined. Additionally, land objectives will be addressed using the synthetic aperture radar incorporated in the payload.

  17. Er3+ fluorescence in rare-earth aluminate glass

    NASA Astrophysics Data System (ADS)

    Weber, Richard; Hampton, Scott; Nordine, Paul C.; Key, Thomas; Scheunemann, Richard

    2005-08-01

    Er3+ ion fluorescence was excited with a 980-nm pump laser in Er-doped rare-earth aluminate (REAl) glasses with Er-dopant concentrations from 0.5-30mol% (oxides basis). The spectral and decay characteristics were measured at ˜1550nm from Er3+I13/24 and at ˜2750nm from Er3+I11/24. Red and green light emissions were also observed, from Er3+F9/24 and S3/24+H11/22, respectively. The fluorescence decay rates are described by a model that yields an accurate fit of results at Er concentrations from 0.5to7mol%. The radiative lifetime of Er3+I13/24 in Er:REAl glass is 6.12±0.26ms. Hydroxyl ion quenching occurs at a rate given by 9.88×10-20 aOHnEr Hz, where aOH is the glass absorption coefficient (in cm-1) at a wavelength of 2950nm and nEr is the total Er ion concentration. The I13/24 upconversion rate constant increases with the Er concentration to 1.35+0.05×10-18width="0.3em"/>cm3/s at and above 7-mol% Er2O3. Er3+I11/24 fluorescence decays primarily by multiphonon quenching to I13/24, at 7700±800Hz, a rate that is slightly less than in tellurite glasses. The addition of 20-mol% silica to the glass has only a small influence on the fluorescence decay rates and greatly improves glass formation from the liquid to allow melting and casting of Er-doped REAl glass from platinum crucibles. The application of these Er-doped glasses in laser and optical device applications is briefly discussed.

  18. Crystalline evolution and large coercivity in Dy-doped (Nd,Dy)2Fe14B/α-Fe nanocomposite magnets

    NASA Astrophysics Data System (ADS)

    The, N. D.; Hoa, N. Q.; Oh, S. K.; Yu, S. C.; Anh, H. D.; Vu, L. V.; Chau, N.

    2007-01-01

    Nanocomposite hard magnetic materials (Nd,Dy)4.5Fe77.5B18 (No. 1) and (Nd,Dy)4.5Fe76B18Nb1.2Cu0.3 (No. 2) have been prepared by crystallizing amorphous ribbons, fabricated by single roll melt-spinning. The evolution of a multiphase structure was monitored by an x-ray diffractometer and by thermomagnetic measurement. We observed that, at annealing temperatures below 670 °C, there is crystallization of soft phase Fe3B and a small amount of hard phase Nd2Fe14B. At annealing temperatures above 670 °C, crystallization of α-Fe and probably Dy2Fe14B phases with large magnetocrystalline anisotropy led to a drastic enhancement in the hard magnetic properties of the materials. The maximum value of HC is found to be 4.2 kOe for sample No. 1. For sample No. 2, with co-doping of Nb and Cu, nanostructure refinement yields a strong enhancement in exchange coupling between the component phases. Thereby, we obtained high reduced-remanence of 0.78, high remanence of 1.15 and a high (BH)max value up to 16.2 MGOe.

  19. Occurrence of magnetoelectric effect correlated to the Dy order in Dy{sub 2}NiMnO{sub 6} double perovskite

    SciTech Connect

    Masud, Md G.; Dey, K.; Ghosh, A.; Majumdar, S.; Giri, S.

    2015-08-14

    Magnetic, dielectric, and ac conductivity as well as room temperature structural and Raman studies are performed on double perovskite Dy{sub 2}NiMnO{sub 6}. The crystal structure of the compound adopts monoclinic P2{sub 1}/n space group, where alternate Mn and Ni distorted octahedral are arranged in anti-phase a{sup −} a{sup −} b{sup +} order in Glazer notation. Magnetization studies show two magnetic transitions around 100 K and 20 K which are related to the ordering of transition and rare earth cations moment, respectively. Temperature dependent dielectric permittivity shows Havriliak-Negami type thermally activated dielectric relaxation. The ac conductivity at different temperature is found to follow Jonscher power law behavior. Time-temperature scaling of the conductivity spectra reveals that the charge transport dynamics is independent of temperature. Intriguingly, an anomaly in the dielectric constant is observed close to the order of Dy moment which indicates intrinsic magnetoelectric coupling. The hybridization between Dy and Ni/Mn is suggested to be correlated with the magnetoelectric coupling.

  20. Lattice and magnetic properties of ErVO4 and ErPO4

    NASA Astrophysics Data System (ADS)

    Hirano, Y.; Skanthakumar, S.; Loong, C.-K.; Wakabayashi, N.; Boatner, L. A.

    2002-07-01

    The crystal-field energy-level structure of the Er3+ ground-state multiplet in ErVO4 was investigated by inelastic neutron scattering and magnetic susceptibility methods. The quantitative determination of the crystal-field-level energetics in conjunction with elastic-constant data was used to carry out a detailed analysis of the magnetoelastic contribution to the temperature dependence of the lattice parameters. X-ray-diffraction measurements show that the magnetoelastic effect is small, but the anisotropy with respect to the tetragonal c axis is unusual among the rare-earth orthovanadate and orthophosphate series. It was concluded that in ErVO4 the sixth-order multipole contribution is essential for explaining the observed thermal-expansion anomaly. A similar situation also occurs in the case of ErPO4. This result is contrary to the dominating role of the quadrupole effect found previously in many rare-earth orthovanadates and orthophosphates.

  1. 150. Credit ER. Building reinforced concrete portion of Coleman Canal ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    150. Credit ER. Building reinforced concrete portion of Coleman Canal inverted siphon #2. Longitudinal steel reinforcing rods are visible at bottom. (ER, v. 64 1911 p. 702). - Battle Creek Hydroelectric System, Battle Creek & Tributaries, Red Bluff, Tehama County, CA

  2. 155. Credit ER. Hand cleaning and trimming of Coleman canal ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    155. Credit ER. Hand cleaning and trimming of Coleman canal after excavation by steam shovel. (ER, v. 64 1911 p. 701). - Battle Creek Hydroelectric System, Battle Creek & Tributaries, Red Bluff, Tehama County, CA

  3. Spin glass behavior in the Dy3-xYxTaO7 (0≤x≤1) system

    NASA Astrophysics Data System (ADS)

    Gomez-Garcia, J. Francisco; Escudero, Roberto; Tavizon, Gustavo

    2014-09-01

    Several x-compositions of the polycrystalline Dy3-xYxTaO7 system, crystallizing in the weberite-type structure, were synthesized and structurally characterized using Rietveld refinements based on X-ray diffraction data. In previous magnetic characterization of Dy3TaO7 (x=0), with the same crystal structure, an antiferromagnetic transition at T=2.3 K has been assigned to this compound. On the basis of DC and AC magnetic susceptibilities analyses, we show in this work that all compounds in the range of 0≤x≤1.0 exhibit a spin glass behavior. The nature of the spin glass behavior in Dy3-xYxTaO7, can be attributed to the highly frustrated antiferromagnetic interaction of the Dy3+ sublattice and to the Dy3+-Dy3+ distorted tetrahedra array in the weberite-type structure of this system. By fitting AC susceptibility data, using dynamical scaling theory equations, we conclude that a cluster spin glass is present in Dy3-xYxTaO7 in the low temperature range. Depending on the x-composition, Tg~2.2-3.2 K. In the range 15-300 K the system obeys a Curie-Weiss magnetic behavior.

  4. Luminescence and thermal-quenching properties of Dy³⁺-doped Ba₂CaWO₆ phosphors.

    PubMed

    Yu, Ruijin; Shin, Dong Soo; Jang, Kiwan; Guo, Yue; Noh, Hyeon Mi; Moon, Byung Kee; Choi, Byung Chun; Jeong, Jung Hyun; Yi, Soung Soo

    2014-05-01

    A series of new double perovskite tungstate Ba2CaWO6:xDy(3+) (0.01⩽x⩽0.15) phosphors were synthesized via solid state reaction process. XRD analysis confirmed the phase formation of Ba2CaWO6:Dy(3+) materials. The photoluminescence excitation and emission spectra, concentration effect, thermal-quenching, and decay property were investigated. The phosphor could be excited by the UV light region from 250 to 400 nm, and it exhibits blue (493 nm) and yellow (584 nm) emission corresponding to (4)F(9/2)-(6)H(15/2) transitions and (4)F9/2-(6)H13/2 transitions, respectively. The optimum dopant concentration of Dy(3+) ions in Ba2CaWO6:xDy(3+) is around 5 mol% and the critical transfer distance of Dy(3+) is calculated as 14 Å. The thermal-quenching temperature is 436 K for Ba2CaWO6:0.05Dy(3+). The fluorescence lifetime is also determined in Ba2CaWO6:0.05Dy(3+). PMID:24618202

  5. Optical characterization of YAl3(BO3)4:Dy3+-Tm3+ phosphors under near UV excitation

    NASA Astrophysics Data System (ADS)

    Lokeswara Reddy, G. V.; Rama Moorthy, L.; Packiyaraj, P.; Jamalaiah, B. C.

    2013-10-01

    Dy3+ and Tm3+ co-doped YAl3(BO3)4 (YAB) phosphors were prepared by solid-state reaction method at 1200 °C/3 h. The average crystallite size was determined as 52.09 nm from the X-ray diffraction measurements. Upon 352 and 359 nm near ultra violet excitation, the YAB:Dy3+-Tm3+ phosphors exhibit Dy3+:4F9/2 → 6HJ (J = 15/2, 13/2, 11/2) and Tm3+:1D2 → 3F4 transitions with different luminescence intensity. The photoluminescence emission and decay measurements revealed the energy transfer from Dy3+ to Tm3+ ions under 359 nm excitation only. The energy transfer between Dy3+ and Tm3+ takes place in Dy3+-Tm3+ clusters through exchange interaction mechanism. The Commission International de I'Eclairage chromaticity coordinates of YAB:Tm3+ phosphor (λex = 359 nm) were found very close to the European Broadcasting Union and National Television Standard Committee illuminants. The emission color of the studied phosphors could be tuned from blue-to-white as a function of excitation wavelength. The YAB:Dy3+-Tm3+ phosphors can be used as potential candidates in display technology.

  6. Optimizing white light luminescence in Dy3+-doped Lu3Ga5O12 nano-garnets

    NASA Astrophysics Data System (ADS)

    Haritha, P.; Martín, I. R.; Linganna, K.; Monteseguro, V.; Babu, P.; León-Luis, S. F.; Jayasankar, C. K.; Rodríguez-Mendoza, U. R.; Lavín, V.; Venkatramu, V.

    2014-11-01

    Trivalent dysprosium-doped Lu3Ga5O12 nano-garnets have been prepared by sol-gel method and characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, dynamic light scattering, and laser excited spectroscopy. Under a cw 457 nm laser excitation, the white luminescence properties of Lu3Ga5O12 nano-garnets have been studied as a function of the optically active Dy3+ ion concentration and at low temperature. Decay curves for the 4F9/2 level of Dy3+ ion exhibit non-exponential nature for all the Dy3+ concentrations, which have been well-fitted to a generalized energy transfer model for a quadrupole-quadrupole interaction between Dy3+ ions without diffusion. From these data, a simple rate-equations model can be applied to predict that intense white luminescence could be obtained from 1.8 mol% Dy3+ ions-doped nano-garnets, which is in good agreement with experimental results. Chromaticity color coordinates and correlated color temperatures have been determined as a function of temperature and are found to be within the white light region for all Dy3+ concentrations. These results indicate that 2.0 mol% Dy3+ ions doped nano-garnet could be useful for white light emitting device applications.

  7. Improvement and luminescent mechanism of Bi4Si3O12 scintillation crystals by Dy3+ doping

    NASA Astrophysics Data System (ADS)

    Yang, Bobo; Xu, Jiayue; Zhang, Yan; Zeng, Haibo; Tian, Tian; Chu, Yaoqing; Pan, Yubai; Cui, Qingzhi

    2016-01-01

    Bi4Si3O12:Dy (BSO:Dy) crystals have been grown by the modified vertical Bridgeman method and doping effects on light yield have been investigated. Doped with small amount of Dy2O3 (0.05-0.3 mol%), the light yield and energy resolution of BSO crystals were improved significantly. However, high concentrations of Dy2O3 doping resulted in the decrease of light yield. Pulse height measurement under γ-ray irradiation shows that 0.1 mol% Dy2O3 doping can make the relative light yield of BSO from 24.6% to 35.8% of BGO crystal, with fast decay time of ~90 ns. X-ray excited radioluminescence spectra showed Dy doping has an extra emission in the host emission band (Bi3+ emission) and acts as a sensitizer to the Bi luminescent center. These results indicate that BSO:Dy crystal could be one of promising candidates for replacing BGO in some application such as electromagnetic calorimeter and dual readout in nuclear or high energy physics.

  8. Magnetic properties of Dy-diffused Nd-Fe-B powder prepared by crystallization from amorphous state

    NASA Astrophysics Data System (ADS)

    Fukunaga, Hirotoshi; Yamamoto, Ikuo; Nakano, Masaki; Yanai, Takeshi

    2012-04-01

    The method of enhancing coercivity of isotropic Nd-Fe-B flakes using simultaneous diffusion of Dy and crystallization from the amorphous state was also applied to Nd-Fe-B powders, in this study. Metal Dy coating was synthesized on amorphous Nd2.36Fe14B1.05 powders by the vapor deposition method, and the powders were crystallized by a flash annealing. Simultaneous diffusion of Dy from their surfaces using the crystallization enhanced the coercivity of isotropic Nd-Fe-B powders. The coercivity Hc increased and the remanence Mr decreased nearly linearly with the amount of Dy, and the coating of 4.5 wt.% Dy resulted in 25.3% increase in Hc and 6.5% decrease in Mr. The decrease in Mr of the Nd-Fe-B powders is nearly the same in magnitude to that previously reported for Nd2.36Fe14B1.05 flakes, which suggests that the method of Dy diffusion using crystallization from amorphous state is applicable to Nd-Fe-B amorphous powders as well as flakes. The energy-dispersive X-ray spectroscopy revealed that Dy coating is inhomogeneous, and a further enhancement in Hc is expected by improving the coating method.

  9. The cervical malignant cells display a down regulation of ER-α but retain the ER-β expression

    PubMed Central

    López-Romero, Ricardo; Garrido-Guerrero, Efraín; Rangel-López, Angélica; Manuel-Apolinar, Leticia; Piña-Sánchez, Patricia; Lazos-Ochoa, Minerva; Mantilla-Morales, Alejandra; Bandala, Cindy; Salcedo, Mauricio

    2013-01-01

    The human cervix is a tissue target of sex steroid hormones as estradiol (E2) which exerts its action through of the estrogen receptors alpha and beta (ER-α and ER-β). In this study we investigated the expression of ER-α and ER-β in human invasive cervical carcinomas using immunohistochemistry and RT-PCR analyses and compared with that observed in the corresponding normal tissue. The results show nuclear expression of ER-α mainly in the first third of normal cervical epithelium, however, decreased or absent expression were present in invasive cervical carcinoma, indicating that expression of ER-α is lost in cervical cancer. Nevertheless, by RT-PCR we were able to demonstrate mRNA expression of ER-α in invasive cervical tissues. These results suggest that loss of ER-α could be due to a mechanism of post-transcriptional and/or post-translational regulation of its gene during the progression to invasive carcinoma. On the other hand, ER-β was expressed in normal cervix with an expression pattern similar to ER-α. In addition to its nuclear localization, cytoplasmic immunoreaction of ER-β was present in the epithelium of invasive cervical carcinomas, suggesting an association between cytoplasmic ER-β expression and invasive phenotype in the cervical tumors. In summary, the results show that the cervical malignant cells tend to loss the ER-α but maintain the ER-β actively expressed. Loss of expression of ER-α in neoplastic tissue suggests that the estrogenic effects could be conducted through the ER-β in human neoplastic cervical tissue. More detailed studies are needed to confirm this suggestion and to determine the role of ER-β in cervical cancer. PMID:23923078

  10. An evaluation of UV protection imparted by cotton fabrics dyed with natural colorants

    PubMed Central

    Sarkar, Ajoy K

    2004-01-01

    Background The ultraviolet properties of textiles dyed with synthetic dyes have been widely reported in literature. However, no study has investigated the ultraviolet properties of natural fabrics dyed with natural colorants. This study reports the Ultraviolet Protection Factor (UPF) of cotton fabrics dyed with colorants of plant and insect origins. Methods Three cotton fabrics were dyed with three natural colorants. Fabrics were characterized with respect to fabric construction, weight, thickness and thread count. Influence of fabric characteristics on Ultraviolet Protection Factor was studied. Role of colorant concentration on the ultraviolet protection factor was examined via color strength analysis. Results A positive correlation was observed between the weight of the fabric and their UPF values. Similarly, thicker fabrics offered more protection from ultraviolet rays. Thread count appears to negatively correlate with UPF. Dyeing with natural colorants dramatically increased the protective abilities of all three fabric constructions. Additionally, within the same fabric type UPF values increased with higher depths of shade. Conclusion Dyeing cotton fabrics with natural colorants increases the ultraviolet protective abilities of the fabrics and can be considered as an effective protection against ultraviolet rays. The UPF is further enhanced with colorant of dark hues and with high concentration of the colorant in the fabric. PMID:15509304

  11. Project DyAdd: Visual Attention in Adult Dyslexia and ADHD

    ERIC Educational Resources Information Center

    Laasonen, Marja; Salomaa, Jonna; Cousineau, Denis; Leppamaki, Sami; Tani, Pekka; Hokkanen, Laura; Dye, Matthew

    2012-01-01

    In this study of the project DyAdd, three aspects of visual attention were investigated in adults (18-55 years) with dyslexia (n = 35) or attention deficit/hyperactivity disorder (ADHD, n = 22), and in healthy controls (n = 35). Temporal characteristics of visual attention were assessed with Attentional Blink (AB), capacity of visual attention…

  12. An alternative method for immediate dose estimation using CaSO4:Dy based TLD badges

    NASA Astrophysics Data System (ADS)

    Singh, A. K.; Menon, S. N.; Dhabekar, Bhushan; Kadam, Sonal; Chougaonkar, M. P.; Babu, D. A. R.

    2014-11-01

    CaSO4:Dy based Thermoluminescence dosimeters (TLDs) are being used in country wide personnel monitoring program in India. The TL glow curve of CaSO4:Dy consists of a dosimetric peak at 220 °C and a low temperature peak at 120 °C which is unstable at room temperature. The TL integral counts in CaSO4:Dy reduces by 15% in seven days after irradiation due to the thermal fading of 120 °C TL peak. As the dosimetric procedure involves total integrated counts for dose conversion, the dosimeters are typically read about a week after receiving. However in the event of a suspected over exposure, where urgent processing is expected, this poses limitation. Post irradiation annealing treatment is used in such cases of immediate readout of cards. In this paper we report a new and easier to use technique based on optical bleaching for the urgent processing of TLD cards. Optical bleaching with green LED (∼555 nm photons) of 25,000 lux for one and half hour removes the low temperature TL peak without affecting the dosimetric peak. This method can be used for immediate dose estimation using CaSO4:Dy based TLD badges.

  13. Dyed and Printed Textiles: Javanese Batik [and] Dutch Wax Prints [and] West African Adire. Third Edition.

    ERIC Educational Resources Information Center

    Burke, Sue

    Three booklets focusing on dyed and printed textile techniques of Java, West Africa, and the Netherlands describe historical and ethnographic materials as well as the development of particular technical traditions. Each section may be used alone or with either or both of the others. When used together, these booklets illustrate the…

  14. Synthesis, structures and magnetic characterizations of isostructural tetranuclear Ln4 clusters (Ln = Dy, Ho, and Eu).

    PubMed

    Koo, Bong Ho; Lim, Kwang Soo; Ryu, Dae Won; Lee, Woo Ram; Koh, Eui Kwan; Hong, Chang Seop

    2013-05-21

    Isostructural tetranuclear clusters [Ln4(salen)6]·xH2O [Ln = Dy, 1·5.5H2O; Ho, 2·4.6H2O; Eu, 3·5.2H2O; salen = N,N'-ethylenebis(salicylideneiminato)dianion] were prepared by self-assembling the corresponding lanthanide ions and a quadridentate Schiff base. Interestingly, the Ln ions are surrounded by the N- and O-donors of the Schiff bases, leading to seven- and eight-coordinate environments. The heptacoordinated Ln centers adopt a distorted capped trigonal prism, while the octacoordinated Ln atoms are in a dodecahedral disposition. The Dy complex exhibits slow magnetic relaxation, characteristic of a single-molecule magnet. Two relaxation modes in the Dy system are evident when H(dc) = 1.4 kG is applied, which is attributable to the existence of the dissimilar coordination geometries around Dy. In comparison, the Ho and Eu analogues were magnetically inspected, displaying no typical slow magnetic relaxation. These findings elucidate that the metal component in the system plays a central role in the occurrence of the magnetization relaxation process. The pronounced long-range order may contribute to intrachain exchange couplings and through-space dipolar interactions between adjacent chains. PMID:23525365

  15. Synthesis and magnetic properties of DyMnO3 nanoparticles in mesoporous silica

    NASA Astrophysics Data System (ADS)

    Tajiri, Takayuki; Kohno, Atsushi; Hamamoto, Kenta; Ando, Yuhki; Deguchi, Hiroyuki; Mito, Masaki

    2013-08-01

    We synthesized nanoparticles of the perovskite manganite DyMnO3 in pores of mesoporous silica SBA-15 and investigated their magnetic properties. X-ray diffraction patterns of the nanoparticles indicated successful synthesis of the DyMnO3 nanoparticles with a particle size of about 10 nm in the pores of SBA-15. The temperature dependence of the DC magnetic susceptibility for the DyMnO3 nanoparticles exhibited a pronounced magnetic irreversibility between the field-cooling and the zero-field-cooling susceptibility due to the blocking phenomena and indicated a change of the magnetic exchange interactions from those for the bulk crystal. The in-phase susceptibility χ' and the out-of-phase susceptibility χ″ of the AC susceptibility for the nanoparticles exhibited a peak at the blocking temperature, and that peak shifted toward higher temperature with increasing frequency. Magnetization curves for the nanoparticles were reproduced by using a Langevin function and exhibited a hysteresis loop at temperatures below the blocking temperature. Magnetic size effects and superparamagnetic behaviors were observed in the DyMnO3 nanoparticles.

  16. Giant rotating magnetocaloric effect induced by highly texturing in polycrystalline DyNiSi compound.

    PubMed

    Zhang, Hu; Li, YaWei; Liu, Enke; Ke, YaJiao; Jin, JinLing; Long, Yi; Shen, BaoGen

    2015-01-01

    Large rotating magnetocaloric effect (MCE) has been observed in some single crystals due to strong magnetocrystalline anisotropy. By utilizing the rotating MCE, a new type of rotary magnetic refrigerator can be constructed, which could be more simplified and efficient than the conventional one. However, compared with polycrystalline materials, the high cost and complexity of preparation for single crystals hinder the development of this novel magnetic refrigeration technology. For the first time, here we observe giant rotating MCE in textured DyNiSi polycrystalline material, which is larger than those of most rotating magnetic refrigerants reported so far. This result suggests that DyNiSi compound could be attractive candidate of magnetic refrigerants for novel rotary magnetic refrigerator. By considering the influence of demagnetization effect on MCE, the origin of large rotating MCE in textured DyNiSi is attributed to the coexistence of strong magnetocrystalline anisotropy and highly preferred orientation. Our study on textured DyNiSi not only provides a new magnetic refrigerant with large rotating MCE for low temperature magnetic refrigeration, but also opens a new way to exploit magnetic refrigeration materials with large rotating MCE, which will be highly beneficial to the development of rotating magnetic refrigeration technology. PMID:26159558

  17. Thermal composition of DyF-, HoF-, and TmF-based gases

    NASA Astrophysics Data System (ADS)

    Kaledin, Leonid A.; Holbrook, Robert T.; Kunc, Joseph A.

    1998-04-01

    The partition functions are calculated for gases consisting of Ln and F atoms, Ln+ ions, LnF and F2 molecules, and LnF+ molecular ions (Ln≡Dy, Ho, Tm) and are subsequently used in determining the local thermal equilibrium compositions of such gases.

  18. Spin glass behavior in the weberite related structure Dy3-xYxTaO7

    NASA Astrophysics Data System (ADS)

    Gomez Garcia, Jose; Tavizon, Gustavo; Duran, Alejandro; Escudero, Roberto

    2013-03-01

    Crystalline structures with tetrahedral arrangement of magnetic cations are susceptible to present non-collinear magnetism. Dy3TaO7 with weberite-type crystal structure has this arrangement and could display non-conventional magnetic coupling. Previous magnetic studies on Dy3TaO7 have characterized this as an antiferromagnetic system with TN of about 3 K. In this work magnetic properties of polycrystalline samples of the Dy3-xYxTaO7, with weberite structure are presented. X-Ray diffraction of our samples are single phase in all range of compositions. Magnetic properties measured from 2 - 300 K shown a typical Curie-Weiss behavior with the Dy3+ effective magnetic moment about 10.35 μB. The compositions x =0.66, 0.33, and 0.0 display a maximum in the susceptibility vs. temperature at 2.3, 2.7, and 3 K respectively. This behavior has been previously assigned to an antiferromagnetic transition; however our AC magnetic measurements as a function of frequency indicate a spin glass behavior. Since magnetic cations have tetrahedral arrangement for x =0, a magnetic frustrated state is anticipated for this composition.

  19. Synthesis and afterglow properties of MgAl2O4:Eu2+, Dy3+ nanopowders.

    PubMed

    Xu, Xuhui; Wang, Yuhua; Gong, Yu; Li, Yanqin

    2011-11-01

    The MgAl2O4:Eu2+, Dy3+ nanophosphors with different particle sizes have been synthesized through a simple and inexpensive precipitate approach followed by a post-annealing process. The structure and morphology of the phosphor are characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). According to XRD and TEM results, the particle size of MgAl2O4:Eu2+, Dy3+ could be controlled via changing the ratio of MgSO4/Al2O3, and the obtained samples possess regular morphology. The afterglow properties of MgAl2O4:Eu2+, Dy3+ nanophosphors as a function of particle sizes are investigated by afterglow decay curves. Compared with the bulk phosphor, the nanophosphors exhibit longer afterglow time and higher initial afterglow intensity. In nanophosphors, there exist numerous defects on their surfaces due to the large surface to volume ratio, which generally act as luminescent killers, while some of which, however, can probably act as traps beneficial for the generation of afterglow. In the nanosized MgAl2O4:Eu2+, Dy3+ phosphor, the thermoluminescence results indeed indicate the existence of more traps which are introduced due to the large surface to volume ratio of nanoparticles and that the high temperature sintering process contributes to the longer afterglow in the nanophosphors. PMID:22413308

  20. White Light Emission by Dy3+ Doped Phosphor Matrices: A Short Review.

    PubMed

    Shrivastava, Ravi; Kaur, Jagjeet; Dubey, Vikas

    2016-01-01

    In this review we have studied number of research papers related to white light emission from Dy3+ doped different host matrices. It is observed that most of the Dy3+doped aluminates, silicates, borates etc., emitted blue, green and red colour with specific intensities so that CIE coordinates, appeared near to white light. Correlated Colour Temperature(CCT) values of these phosphors expressed that the white light emission produced, was adaptable to human eyes. Dy3+ ions act as activator in each case. Four peaks at approximately 480,575, 670, and 757 nm could be seen in most of the Dy3+ doped phosphors. Expected transition responsible for these peaks are 4F9/2 → 6H15/2 (Blue Colour), 4F9/2 → 6H13/2 (Green-Yellow Colour), 4F9/2 → 6H11/2 (Red Colour) and 4F9/2 → 6H9/2(Brownish Red Colour). Few of the discussed phosphors exhibited long phosphorescence, starting from several minutes to few hours. Mechanism responsible for long lasting white light emission was also discussed. Five different factors, to recognize the phosphors for its suitability as commercial white light phosphor have been discussed. PMID:26498457

  1. Project DyAdd: Implicit Learning in Adult Dyslexia and ADHD

    ERIC Educational Resources Information Center

    Laasonen, Marja; Väre, Jenni; Oksanen-Hennah, Henna; Leppämäki, Sami; Tani, Pekka; Harno, Hanna; Hokkanen, Laura; Pothos, Emmanuel; Cleeremans, Axel

    2014-01-01

    In this study of the project DyAdd, implicit learning was investigated through two paradigms in adults (18-55 years) with dyslexia (n?=?36) or with attention deficit/hyperactivity disorder (ADHD, n?=?22) and in controls (n?=?35). In the serial reaction time (SRT) task, there were no group differences in learning. However, those with ADHD exhibited…

  2. Synthesis and characterization of CaF{sub 2}:Dy nanophosphor for dosimetric application

    SciTech Connect

    Bhadane, Mahesh S.; Dahiwale, S. S.; Bhoraskar, V. N.; Dhole, S. D.; Patil, B. J.; Kulkarni, M. S.; Bhatt, B. C.

    2015-06-24

    In this work, nanoparticles (NPs) of dysprosium doped calcium fluoride (CaF{sub 2}:Dy) 1 mol % has been prepared using simple chemical co-precipitation method and its thermoluminescence (TL) dosimetric properties were studied. The synthesized nanoparticle sample was characterized by X-ray diffraction (XRD) and the particle size of face centered cubic phase NPs was found around 30 nm. The shape, morphology and size were also observed by scanning electron microscopy (SEM). From gamma irradiated CaF{sub 2}:Dy TL curves, it was observed that the total areas of all the glow peak intensities are dramatically changed with increase in annealing temperature. Further, TL glow curve of the CaF{sub 2}:Dy at 183 °C annealed at 400 °C, showed very sharp linear response in the dose range from 1 Gy to 750 Gy. This linear response of CaF{sub 2}:Dy nanophosphor as a function of gamma dose is very useful from radiation dosimetric point of view.

  3. Transport properties along c-axis of DyNi2B2C

    NASA Astrophysics Data System (ADS)

    Lee, W. C.

    2014-12-01

    We have measured the resistivity along c-axis ρc(H, T) of DyNi2B2C with the applied magnetic field H perpendicular to c-axis for 0 kG < H < 4 kG and temperature range 2 K < T < 300 K. From these, the superconducting upper critical field HC2(T) curve of DyNi2B2C for the c-axis was constructed and our HC2(T) curve from ρc(H, T) measurement has been compared with that from previous known ρab(H, T) result. With additional magnetization isotherms M(H, T) for H ⊥ c and H ∥ c-axis, the anisotropy in HC2(T) curves of the magnetic structure DyNi2N2C, which has the superconducting transition temperature TC is lower than the Néel temperatures TN, might be originated from the additional anisotropic magnetic Dy3+ sublattice.

  4. C-axis Transport Properties of DyNi2 B2 C

    NASA Astrophysics Data System (ADS)

    Lee, W. C.

    2014-03-01

    The resistivity along c-axis ρc(H,T) of DyNi2B2C have been measured with the applied magnetic field H perpendicular and parallel to c-axis, 0 kG DyNi2B2C for the c-axis were constructed for each magnetic fields and our HC2(T) curves from ρc(H,T) measurement have been compared with those from previous known ρab(H,T) results. Since RNi2N2C (R = non magnetic rare earth element) has isotropic electronic structure and properties, the anisotropy in HC2(T) curves of the magnetic DyNi2N2C, which has the superconducting transition temperature, TC, is lower than the Néel temperatures, TN, is thought to be originated from the anisotropic magnetic Dy +3 sublattice.

  5. Optical and structural properties of lithium sodium borate glasses doped Dy3+ ions

    NASA Astrophysics Data System (ADS)

    Dawaud, Raghda Saeif Eddin Said; Hashim, Suhairul; Alajerami, Yasser Saleh Mustafa; Mhareb, M. H. A.; Tamchek, N.

    2014-10-01

    Absorption and emission spectra of lithium sodium borate glass doped with different concentrations of Dy3+ have been reported. The concentration of Dy3+ was varied from 0.3 to 1.3 mol%. The amorphous nature of the prepared samples was confirmed by the X-ray Diffraction (XRD). Fourier transforms infrared (FTIR) spectra, and other significant physical properties (energy band gap, density, ion concentration, molar volume, Polaron radius and inter-nuclear distance) have been analyzed in the light of the different oxidation states of the co-dopant ions. The absorption spectrum showed nine peaks with hypersensitive transition corresponding to 6F11/2 + 6H9/2 at 1256 nm. As a result of 380 nm excitation wavelength, the luminescence spectra showed two characteristic bands at 479 nm and 587 nm. These absorption bands were attributed to 6P15/2 → 6H15/2 and 6P15/2 → 6H13/2 transitions of trivalent Dy3+ ions. The current study indicates that Dy doped lithium sodium borate glasses are attractive for solid-state laser applications.

  6. Laser spectroscopy of Nd 3+ and Dy 3+ ions in lead borate glasses

    NASA Astrophysics Data System (ADS)

    Pisarska, Joanna; Pisarski, Wojciech A.; Ryba-Romanowski, Witold

    2010-07-01

    The spectroscopic and laser properties of Nd 3+ and Dy 3+ ions in lead borate glass were studied. Luminescence spectra recorded in the near-infrared and visible ranges correspond to 4F 3/2- 4I J/2 ( J=9, 11, 13) transitions of Nd 3+ and 4F 9/2- 6H J/2 ( J=11, 13, 15) transitions of Dy 3+, respectively. Luminescence decay curves were analyzed as a function of activator concentration. Luminescence quenching is observed, which is due to Ln-Ln interaction increasing. Several spectroscopic parameters relevant to laser potential of Ln 3+ ions (Ln=Nd, Dy) in lead borate glass were determined. The relatively large values of the quantum efficiency and the room-temperature emission cross-section for the 4F 3/2- 4I 11/2 transition of Nd 3+ at 1061 nm and the 4F 9/2- 6H 13/2 transition of Dy 3+ at 573 nm imply that Ln-doped lead borate glasses can be considered as promising solid-state materials for laser applications.

  7. High Pressure Raman Scattering Study on the Phase Stability of DyVO4

    NASA Astrophysics Data System (ADS)

    Patel, Nishant N.; Garg, Alka B.; Meenakshi, S.; Wani, B. N.; Sharma, S. M.

    2011-07-01

    High pressure Raman spectroscopic investigations have been carried out on rare earth orthovanadate DyVO4 upto 22 GPa. Abrupt changes and appearance of new modes were noted in Raman spectrum above 8 GPa with two phase coexistence over a pressure range of about 8-13 GPa The phase transition was found to be irreversible when pressure is released.

  8. Thermal, optical and structural properties of Dy3+ doped sodium aluminophosphate glasses

    NASA Astrophysics Data System (ADS)

    Kaur, Manpreet; Singh, Anupinder; Thakur, Vanita; Singh, Lakhwant

    2016-03-01

    Trivalent Dysprosium doped sodium aluminophosphate glasses with composition 50P2O5-10Al2O3-(20-x)Na2O-20CaO-xDy2O3 (x varying from 0 to 5 mol%) were prepared by melt quench technique. The density of the prepared samples was measured using Archimedes principle and various physical properties like molar volume, rare earth ion concentration, polaron radius, inter nuclear distance and field strength were calculated using different formulae. The differential scanning calorimetry (DSC) was carried out to study the thermal stability of prepared glasses. The UV Visible absorption spectra of the dysprosium doped glasses were found to be comprised of ten absorption bands which correspond to transitions from ground state 6H15/2 to various excited states. The indirect optical band gap energy of the samples was calculated by Tauc's plot and the optical energy was found to be attenuated with Dy3+ ions. The photoluminescence spectrum revealed that Dy3+ doped aluminophosphate glasses have strong emission bands in the visible region. A blue emission band centred at 486 nm, a bright yellow band centred at 575 nm and a weak red band centred at 668 nm were observed in the emission spectrum due to excitation at 352 nm wavelength. Both FTIR and Raman spectra assert slight structural changes induced in the host glass network with Dy3+ ions.

  9. On the binary helium star DY Centauri: chemical composition and evolutionary state

    SciTech Connect

    Pandey, Gajendra; Rao, N. Kameswara; Jeffery, C. Simon; Lambert, David L. E-mail: nkrao@iiap.res.in E-mail: dll@astro.as.utexas.edu

    2014-10-01

    DY Cen has shown a steady fading of its visual light by about one magnitude in the last 40 yr, suggesting a secular increase in its effective temperature. We have conducted non-local thermodynamic equilibrium (LTE) and LTE abundance analyses to determine the star's effective temperature, surface gravity, and chemical composition using high-resolution spectra obtained over two decades. The derived stellar parameters for three epochs suggest that DY Cen has evolved at a constant luminosity and has become hotter by about 5000 K in 23 yr. We show that the derived abundances remain unchanged for the three epochs. The derived abundances of the key elements, including F and Ne, are as observed for the extreme helium stars resulting from a merger of a He white dwarf with a C-O white dwarf. Thus DY Cen by chemical composition appears to also be a product of a merger of two white dwarfs. This appearance seems to be at odds with the recent suggestion that DY Cen is a single-lined spectroscopic binary.

  10. Electrocatalytic performance of Pt-Dy alloys for direct borohydride fuel cells

    NASA Astrophysics Data System (ADS)

    Šljukić, Biljana; Milikić, Jadranka; Santos, Diogo M. F.; Sequeira, César A. C.; Macciò, Daniele; Saccone, Adriana

    2014-12-01

    The electrochemical oxidation of sodium borohydride (NaBH4) is systematically studied on platinum-dysprosium (Pt-Dy) alloys in alkaline media with respect to application in direct borohydride fuel cells (DBFCs). Using several different techniques, namely cyclic voltammetry, chronoamperometry and chronopotentiometry, reaction parameters are evaluated for NaBH4 electrooxidation in 2 M NaOH supporting electrolyte. The values obtained for the number of electrons exchanged are comparable for the two alloys and close to 2.5. Dependence of Pt-Dy alloys activity for NaBH4 oxidation on the electrolyte composition and temperature is also investigated. Test fuel cell is assembled using Pt-Dy alloy as anode, reaching peak power density of 298 mW cm-2 at current density of 595 mA cm-2 and cell potential of 0.5 V at 25 °C. Pt-Dy alloys exhibit comparable behavior with pure Pt electrode at room temperature, while at higher temperature they exhibit improved Coulombic efficiency, with the advantage of significantly lower price.

  11. Effects of overexpression of high molecular weight glutenin subunit 1Dy10 on wheat tortilla properties.

    PubMed

    Pierucci, Valquíria R M; Tilley, Michael; Graybosch, Robert A; Blechl, Ann E; Bean, Scott R; Tilley, Katherine A

    2009-07-22

    Wheat (Triticum aestivum L.) flour properties necessary for optimal tortilla production have not been identified. Transgenic wheats (Triticum aestivum L.) overexpressing high molecular weight glutenin subunit (HMW-GS) 1Dy10 were used to make tortilla and their quality was evaluated. The level of HMW-GS 1Dy10 in flours derived from transgenic wheats was 2.5-5.8-fold greater than in controls. Polymeric proteins in the transgenic samples had a molecular weight distribution shifted toward larger polymers as indicated by increased levels of polymeric proteins present and greater M(w) averages of the largest fractions in the insoluble polymeric proteins. Dough derived from transgenic wheats had greater resistance to extension and lower extensibility than controls. Tortilla quality evaluation revealed that tortillas originated from transgenic wheats had decreased diameter, greater thickness and rupture force, and lower rollability scores and stretchability than controls. The presence of 1RS chromosomal translocations from rye (Secale cereale L.) in transgenic wheat decreased the negative effects of overexpression of HMW-GS 1Dy10, as tortillas made with this flour mostly exhibited quality properties similar to those made from control flour. Results suggested that the negative effects of overexpression of HMW-GS 1Dy10 on tortilla properties were derived from a nonideal gluten matrix formation. PMID:19537784

  12. Low-spin structure of 156Dy through gamma-ray spectroscopy

    SciTech Connect

    Caprio, M.A.; Zamfir, N.V.; Casten, R.F.; Barton, C.J.; Beausang, C.W.; Cooper, J.R.; Hecht, A.A.; Kruecken, R.; Newman, H.; Novak, J.R.; Pietralla, N.; Wolf, A.; Zyromski, K.E.

    2002-11-27

    Excited states of 156Dy were populated by beta decay and studied through gamma-ray spectroscopy. Extensive data led to improved information of the electromagnetic properties of low-spin states and to a substantially revised level scheme. The results are compared to those of other N=90 isotones and to predictions of the X(5) dynamical symmetry.

  13. Thermoluminescence characterization of Dy(3+) -activated Mg₅ (BO₃ )₃ F low Z(eff) phosphor.

    PubMed

    Wani, Javaid A; Dhoble, N S; Dhoble, S J

    2013-01-01

    Thermoluminescence characteristics of Dy(3+) -activated Mg₅ (BO₃ )₃ F low Z(eff) phosphor are described. The Mg₅ (BO₃ )₃ F phosphor doped with Dy(3+) as activator was prepared by the modified solid-state reaction. Formation of the compound was confirmed by use of X-ray powder diffraction. The X-ray powder diffraction pattern of the as-prepared compound shows a good match with the available JCPDS data. The γ-irradiated Mg₅ (BO₃ )₃ F:Dy(3+) phosphor shows a simple glow curve peaking at about 148°C indicating that only one type of trap is being activated within a particular temperature range. The kinetic parameters, including activation energy and frequency factor were determined using Chen's method. The activation energy and frequency factors were 0.75 eV and 4.508 × 10(9) /s respectively. The Z(eff) ofMg₅ (BO₃ )₃ F:Dy(3+) phosphor was 9.84. PMID:23055350

  14. Experimental observation of ferrielectricity in multiferroic DyMn2O5

    PubMed Central

    Zhao, Z. Y.; Liu, M. F.; Li, X.; Lin, L.; Yan, Z. B.; Dong, S.; Liu, J. -M.

    2014-01-01

    One of the major breakthroughs associated with multiferroicity in recent years is the discovery of ferroelectricity generated by specific magnetic structures in some magnetic insulating oxides such as rare-earth manganites RMnO3 and RMn2O5. An unresolved issue is the small electric polarization. Relatively large electric polarization and strong magnetoelectric coupling have been found in those manganites of double magnetic ions: magnetic rare-earth R ion and Mn ion, due to the strong R-Mn (4f-3d) interactions. DyMn2O5 is a representative example. We unveil in this work the ferrielectric nature of DyMn2O5, in which the two ferroelectric sublattices with opposite electric polarizations constitute the ferrielectric state. One sublattice has its polarization generated by the symmetric exchange striction from the Mn-Mn interactions, while the polarization of the other sublattice is attributed to the symmetric exchange striction from the Dy-Mn interactions. We present detailed measurements on the electric polarization as a function of temperature, magnetic field, and measuring paths. The present experiments may be helpful for clarifying the puzzling issues on the multiferroicity in DyMn2O5 and other RMn2O5 multiferroics. PMID:24496324

  15. Preparation, structural and magnetic characterization of DyCrMnO{sub 5}

    SciTech Connect

    Martinez-Lope, M.J.; Retuerto, M. Garcia-Hernandez, M.; Alonso, J.A.

    2009-03-15

    The title compound has been first synthesized by a citrate technique followed by thermal treatments under moderate oxygen pressure conditions, and characterized by X-ray and neutron powder diffraction (NPD) and magnetization measurements. The crystal structure of DyCrMnO{sub 5} has been refined from NPD data in the space group Pbam; a=7.2617(6) A, b=8.5161(6) A, and c=5.7126(5) A at 295 K. This oxide is isostructural with RMn{sub 2}O{sub 5} oxides (R=rare earths) and it contains infinite chains of (Cr, Mn){sup 4+}O{sub 6} octahedra-sharing edges, linked together by (Mn, Cr){sup 3+}O{sub 5} pyramids and DyO{sub 8} units. The high degree of antisite disordering exhibited by DyCrMnO{sub 5} is noteworthy. The octahedral positions are occupied by roughly 50% of Mn and Cr cations, and the pyramidal groups contain two thirds of Mn and one third of Cr cations. We assume that Mn and Cr cations at the octahedral positions exhibit a tetravalent oxidation state, whereas the metals at the pyramidal positions are trivalent, in order to preserve the electroneutrality of this oxide. The susceptibility vs temperature curve of DyCrMnO{sub 5} does not suggest the establishment of a long-range magnetic structure even at low temperatures; the NPD technique does not provide any signal of magnetic ordering, since the reflections do not show any magnetic contribution. - Graphical abstract: DyCrMnO{sub 5} is isostructural with DyMn{sub 2}O{sub 5}, belonging to the Pbam space group. The crystal structure contains infinite chains of edge-sharing Mn{sup 4+}O{sub 6} octahedra, interconnected by dimer units of Cr{sup 3+}O{sub 5} square pyramids. The low-temperature neutron powder diffraction (NPD) patterns do not show any magnetic contribution, indicating that a full long-range magnetic ordering is not established down to low temperature, although the Dy{sup 3+} magnetic moments are susceptible to be polarized by an external magnetic field at the lowest temperature of 5 K.

  16. MgO:Dy{sup 3+} nanophosphor: Self ignition route, characterization and its photoluminescence properties

    SciTech Connect

    Devaraja, P.B.; Avadhani, D.N.; Nagabhushana, H.; Prashantha, S.C.; Sharma, S.C.; Nagabhushana, B.M.; Nagaswarupa, H.P.; Daruka Prasad, B.

    2014-11-15

    For the first time series of MgO phosphors doped with different concentrations of Dy{sup 3+} (1–9 mol%) were prepared by solution combustion method using glycine as a fuel. The final products were well characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. The powder X-ray diffraction patterns of the as-formed product show single cubic phase. The crystallite size estimated using Scherrer's method was found to be in the range 5–15 nm and the same was confirmed by transmission electron microscopy result. Photoluminescence properties of Dy{sup 3+} (1–9 mol%) doped MgO for near ultra violet excitation (325 nm) was studied in order to investigate the possibility of its use in white light emitting diode applications. The emission spectra consists of intra 4f transitions of Dy{sup 3+}, namely {sup 4}F{sub 9/2} → {sup 6}H{sub 15/2} (483 nm), and {sup 4}F{sub 9/2} → {sup 6}H{sub 13/2} (573 nm). Further, the emission at 573 nm shows strong yellow emission and can be applied to the yellow emission of phosphor for the application for near ultraviolet excitation. The intensity of yellow emission was attributed to intrinsic defects, especially oxygen-vacancies, which could assist the energy transfer from the MgO host to the Dy{sup 3+} ions. The Commission International De I-Eclairage chromaticity co-ordinates were calculated from emission spectra, the values (x,y) were very close to the National Television System Committee standard value of white emission. Therefore, the present phosphor was highly useful for display applications. - Graphical Abstract: PL emission spectra and CIE diagram of MgO:Dy{sup 3+} nanophosphor. - Highlights: • MgO:Dy{sup 3+} prepared by simple and low cost LCS method at low temperature (400 °C). • Characteristic emission peaks of Dy{sup 3+} ion at ∼ 483 and 573 nm are recorded. • CIE co-ordinate values located in the white region.

  17. White light emission in host-sensitized Dy3+-single-doped NaIn(WO4)2 phosphors

    NASA Astrophysics Data System (ADS)

    Xiong, F. B.; Lin, H. F.; Wang, L. J.; Meng, X. G.; Zhu, W. Z.

    2015-02-01

    A novel white NaIn1-x(WO4)2: xDy3+ (x=0, 0.02, 0.04, 0.06 and 0.08) phosphors in pure phase were prepared via high temperature solid-state reaction, and luminescent properties of the phosphors were investigated. The crystal structure of the phosphor was characterized by powder X-ray diffraction, and the spectroscopic properties of Dy3+-doped NaIn(WO4)2 were investigated by diffuse reflectance spectra, photoluminescence emission and photoluminescence excitation spectroscopy. Those spectra illustrated that the Dy3+-doped NaIn(WO4)2 phosphors could be efficiently excited by the host-sensitized excitation in the spectral range of 280-350 nm, and the host-sensitized excitation is more efficient than the Dy3+ excitation. The 6 mol% Dy3+ doping concentration in NaIn(WO4)2 is optimum, and the luminescence concentration quenching occurs beyond the 6 mol% concentration. The concentration quenching mechanism could be attributed to the dipole-dipole interaction between the Dy3+ ions. The CIE color coordinate of the 6 mol% Dy3+-doped NaIn(WO4)2 is (0.319, 0.325). The present work suggests that Dy3+-doped NaIn(WO4)2 could be a promising host-sensitized phosphor applied in white LEDs, and white emission can be obtained by combining the blue host emission with the yellow Dy3+ emission.

  18. Ethylene Perception by the ERS1 Protein in Arabidopsis1

    PubMed Central

    Hall, Anne E.; Findell, Jennifer L.; Schaller, G. Eric; Sisler, Edward C.; Bleecker, Anthony B.

    2000-01-01

    Ethylene perception in Arabidopsis is controlled by a family of five genes, including ETR1, ERS1 (ethylene response sensor 1), ERS2, ETR2, and EIN4. ERS1, the most highly conserved gene with ETR1, encodes a protein with 67% identity to ETR1. To clarify the role of ERS1 in ethylene sensing, we biochemically characterized the ERS1 protein by heterologous expression in yeast. ERS1, like ETR1, forms a membrane-associated, disulfide-linked dimer. In addition, yeast expressing the ERS1 protein contains ethylene-binding sites, indicating ERS1 is also an ethylene-binding protein. This finding supports previous genetic evidence that isoforms of ETR1 also function in plants as ethylene receptors. Further, we used the ethylene antagonist 1-methylcyclopropene (1-MCP) to characterize the ethylene-binding sites of ERS1 and ETR1. We found 1-MCP to be both a potent inhibitor of the ethylene-induced seedling triple response, as well as ethylene binding by yeast expressing ETR1 and ERS1. Yeast expressing ETR1 and ERS1 showed nearly identical sensitivity to 1-MCP, suggesting that the ethylene-binding sites of ETR1 and ERS1 have similar affinities for ethylene. PMID:10938361

  19. Preparation of Dy-123 system superconductor composed with Pt Rh wires

    NASA Astrophysics Data System (ADS)

    Shimada, H.; Fujimoto, H.; Yoshizawa, S.

    2008-09-01

    The melt-textured DyBa 2Cu 3O x (Dy-123) system superconductors were grown by means of the top seeding and temperature gradient method. Ag 2O powder of 30 wt% was added to the mixture of Dy-123 and Dy-211 powder. The pellet of 20 mm in diameter and 20 mm in thickness was prepared using coaxial pressing equipment. For improving the mechanical property and resolving the hot-spot problem, platinum-rhodium (Pt-Rh) alloy wires 0.4 mm in diameter and 18 mm in length were added from the surface into the bottom of the pellet. The pellet was partially melted in air at 1030 °C for one hr and rapidly cooled to 975 °C in a bulk material, where Nd-123 seed crystal was placed in contact with the top surface of the bulk. After the seeding, the bulk was cooled to 925 °C, and then furnace-cooled to the room temperature. Finally, the sample was annealed in oxygen atmosphere. The single-domain superconducting bulk containing two Pt-Rh wires was fabricated. There were intermediate layers and no voids or cracks between the metal wire and Dy-123 superconducting oxide. Single peak in the trapped field distribution with the maximum value of about 0.12 T at 77.3 K was obtained, which was almost the same as that of the bulk without wires. It was concluded that the superconductivity of the melt textured bulk was not deteriorated by the addition of Pt-Rh wires.

  20. Microstructure evaluation for Dy-free Nd-Fe-B sintered magnets with high coercivity

    NASA Astrophysics Data System (ADS)

    Goto, R.; Matsuura, M.; Sugimoto, S.; Tezuka, N.; Une, Y.; Sagawa, M.

    2012-04-01

    Nd-Fe-B sintered magnets are used for motors of hybrid or electric vehicles due to their high energy products. Dy is added to Nd-Fe-B sintered magnets to work in a high temperature environment. Although the addition of Dy decreases the magnetization of Nd-Fe-B magnets, it increases coercivity; a decrease in the amount of Dy is strongly required. Recently, Nd-Fe-B sintered magnets with a grain size of 1 μm achieved high coercivity of ˜20 kOe without the addition of Dy or other heavy rare earth elements. In this paper, the microstructure of their magnets was observed and compared to magnets with a grain size of ˜3 μm. The coercivity of magnets consisting of larger particles was 17 kOe. Microstructures were observed by the scanning electron microscope and the shapes of grains and the distribution of the Nd-rich phase were evaluated. The observation was promoted in two directions. One direction is the plane perpendicular to the magnetically aligned direction (c plane side) and the other is the side parallel to the magnetically aligned direction (c axis side). For magnets consisting of smaller particles, the shapes of grains are isotropic for the c plane side and elongated for the c axis side. The angle of minor axis prefers to be parallel to magnetically aligned direction. The distribution of the Nd-rich phase for magnets was also evaluated for both magnets. The distribution of the Nd-rich phase at triple junctions for the magnets with smaller particles becomes homogeneous compared to that for magnets with larger particles. It is considered that Dy-free magnets with high coercivity were realized by the achievement of homogeneous distribution of Nd-rich phase besides decreasing grain size.

  1. Optical spectroscopy of Dy3+ doped borate glasses for luminescence applications

    NASA Astrophysics Data System (ADS)

    Venkata Rao, K.; Babu, S.; Venkataiah, G.; Ratnakaram, Y. C.

    2015-08-01

    Dy3+ ion embedded in (50 - x)B2O3-20PbO-15MgF2-15NaCl-xDy2O3(x = 0.2, 0.4, 0.6, 0.8, 1.0 and 2.0 mol%) borate glasses are prepared and investigated using Differential Thermal Analysis (DTA), X-ray Diffractometer (XRD), Raman spectra, optical absorption and photoluminescence (PL) as function of different concentrations. Thermal stability of borate glass has been calculated from DTA profiles. The amorphous nature of glass matrix is confirmed by XRD. Based on Raman spectra, the functional groups that are present in the glass matrices have been analyzed. Based on the Judd-Ofelt theory, three spectral intensity parameters Ωλ (λ = 2, 4, 6) are calculated from absorption spectra. These parameters are used to determine radiative transition probabilities (AR), radiative lifetimes (τR) and branching ratios (βR) of Dy3+ transitions from the excited state manifolds to corresponding lower laying multiplet manifolds. PL spectra show two intense and one weak band due to 4F9/2 → 6H15/2 (blue), 6H13/2 (yellow) and 6H11/2 (red) transitions respectively. For these transitions luminescence properties are studied. With the increase in the concentration of Dy3+ ions, intensity increases up to 0.8 mol% and then concentration quenching is observed. This is (0.8 mol%) the optimized concentration for the present prepared glasses. Lifetimes (τexp) are calculated for all the glass matrices from decay curve analysis. Spectroscopic and luminescence properties at 0.8 mol% doped dysprosium ion are compared with other reported glass matrices. From the above analysis suggest that 0.8 mol% of Dy3+ doped borate glasses can be useful for yellow lighting applications in the visible spectral region.

  2. CaSO4:DY,Mn: A new and highly sensitive thermoluminescence phosphor for versatile dosimetry

    NASA Astrophysics Data System (ADS)

    Bahl, Shaila; Lochab, S. P.; Kumar, Pratik

    2016-02-01

    With the advent of newer techniques for dose reduction coupled with the development of more sensitive detectors, the radiation doses in radiological medical investigation are decreasing. Nevertheless, keeping the tenet in mind that all radiation doses could entail risk, there is a need to develop more sensitive dosimeters capable of measuring low doses. This paper gives the account of the development of a new and sensitive phosphor CaSO4:Dy,Mn and its characterization. The standard production procedure based on the recrystallization method was used to prepare CaSO4:Dy,Mn. The Thermoluminescence (TL) studies were carried out by exposing it with gamma radiation (Cs-137) from 10 μGy to 100 Gy. The theoretical studies to determine the number of peaks and kinetic parameters related to the TL glow peaks in CaSO4:Dy,Mn was performed using the Computerized Glow Curve Deconvolution (CGCD) method. Experiments were performed to determine optimum concentration of the dopants Dysprosium (Dy) and Mangnese (Mn) in the host CaSO4 so that maximum sensitivity of the phosphor may be achieved. The optimum dopant concentration turned out to be 0.1 mol%. As there were two dopants Dy and Mn their relative ratio were varied in steps of 0.025 keeping the concentration of total dopant (Dy and Mn) 0.1 mol% always. The maximum TL intensity was seen in the CaSO4:Dy(0.025),Mn(0.075) combination. The TL sensitivity of this phosphor was found to be about 2 and 1.8 times higher than that of popular phosphor CaSO4:Dy and LiF:Mg,Cu,P (TLD-700H) respectively. This new phosphor CaSO4:Dy,Mn showed fading of 11% which is similar to that of the standard phosphor CaSO4:Dy. The paper concludes that the new, highly sensitive TL phosphor CaSO4:Dy,Mn has shown higher sensitivity and hence the potential to replace commonly used CaSO4:Dy.

  3. Calculations of the magnetic entropy change in amorphous through a microscopic anisotropic model: Applications to Dy{sub 70}Zr{sub 30} and DyCo{sub 3.4} alloys

    SciTech Connect

    Ranke, P. J. von Nóbrega, E. P.; Ribeiro, P. O.; Alvarenga, T. S. T.; Lopes, P. H. O.; Sousa, V. S. R. de; Oliveira, N. A. de; Caldas, A.; Alho, B. P.; Carvalho, G.; Magnus, A.

    2014-10-14

    We report theoretical investigations on the magnetocaloric effect, described by the magnetic entropy change in rare earth—transition metal amorphous systems. The model includes the local anisotropy on the rare earth ions in Harris-Plischke-Zuckermann assumptions. The transition metals ions are treated in terms of itinerant electron ferromagnetism and the magnetic moment of rare earth ions is coupled to the polarized d-band by a local exchange interaction. The magnetocaloric effect was calculated in DyCo{sub 3.4} system, which presents amorphous sperimagnetic configuration. The calculations predict higher refrigerant capacity in the amorphous DyCo{sub 3.4} than in DyCo{sub 2} crystal, highlighting the importance of amorphous magnetocaloric materials. Our calculation of the magnetocaloric effect in Dy{sub 70}Zr{sub 30}, which presents amorphous asperomagnetic configuration, is in good agreement with the experimental result. Furthermore, magnetic entropy changes associated with crystal-amorphous configurations change are estimated.

  4. ER-12-1 completion report

    SciTech Connect

    Russell, C.E.; Gillespie, D.; Cole, J.C.; Drellack, S.L.

    1996-12-01

    The objective of drillhole ER-12-1 was to determine the hydrogeology of paleozoic carbonate rocks and of the Eleana Formation, a regional aquitard, in an area potentially downgradient from underground nuclear testing conducted in nearby Rainier Mesa. This objective was addressed through the drilling of well ER-12-1 at N886,640.26 E640,538.85 Nevada Central Coordinates. Drilling of the 1094 m (3588 ft) well began on July 19, 1991 and was completed on October 17, 1991. Drilling problems included hole deviation and hole instability that prevented the timely completion of this borehole. Drilling methods used include rotary tri-cone and rotary hammer drilling with conventional and reverse circulation using air/water, air/foam (Davis mix), and bentonite mud. Geologic cuttings and geophysical logs were obtained from the well. The rocks penetrated by the ER-12-1 drillhole are a complex assemblage of Silurian, Devonian, and Mississippian sedimentary rocks that are bounded by numerous faults that show substantial stratigraphic offset. The final 7.3 m (24 ft) of this hole penetrated an unusual intrusive rock of Cretaceous age. The geology of this borehole was substantially different from that expected, with the Tongue Wash Fault encountered at a much shallower depth, paleozoic rocks shuffled out of stratigraphic sequence, and the presence of an altered biotite-rich microporphyritic igneous rock at the bottom of the borehole. Conodont CAI analyses and rock pyrolysis analyses indicate that the carbonate rocks in ER-12-1, as well as the intervening sheets of Eleana siltstone, have been thermally overprinted following movement on the faults that separate them. The probable source of heat for this thermal disturbance is the microporphyritic intrusion encountered at the bottom of the hole, and its age establishes that the major fault activity must have occurred prior to 102.3+0.5 Ma (middle Cretaceous).

  5. Meyers Großer Sternenatlas

    NASA Astrophysics Data System (ADS)

    Brunier, Serge; Fujii, Akira

    Unendliche Weiten mal ganz aus der Nähe betrachtet. Meyers Großer Sternenatlas ist ein außergewöhnlicher Bildband über den Sternenhimmel, der die Sternbilder erstmals im gleichen Größenverhältnis zeigt, wie sie am Himmel erscheinen. Die sensationellen Astrofotos und aktuellen Aufnahmen des Hubble-Weltraumteleskops werden Gelegenheitsbeobachter und Hobbyastronomen gleichermaßen begeistern.

  6. MicroRNAs meet calcium: joint venture in ER proteostasis.

    PubMed

    Finger, Fabian; Hoppe, Thorsten

    2014-11-01

    The endoplasmic reticulum (ER) is a cellular compartment that has a key function in protein translation and folding. Maintaining its integrity is of fundamental importance for organism's physiology and viability. The dynamic regulation of intraluminal ER Ca(2+) concentration directly influences the activity of ER-resident chaperones and stress response pathways that balance protein load and folding capacity. We review the emerging evidence that microRNAs play important roles in adjusting these processes to frequently changing intracellular and environmental conditions to modify ER Ca(2+) handling and storage and maintain ER homeostasis. PMID:25372053

  7. Optical properties of RbMnF3:Er3+

    NASA Astrophysics Data System (ADS)

    Iverson, M. V.; Sibley, W. A.

    1980-03-01

    Absorption, emission, excitation, and lifetime data are presented for RbMnF3:Er3+. Evidence for Mn2+ --> Er3+ energy transfer was found from the Er3+ excitation spectra and the temperature dependence of the Mn2+ and Er3+ emissions. The presence of Er3+ in the lattice slightly changed the temperature dependence of the Mn2+ lifetime. Radiative and radiationless transitions are discussed in terms of the model of Flaherty and Di Bartolo and the quantum-mechanical single-configuration coordinate model of Struck and Fonger.

  8. ER contact sites direct late endosome transport.

    PubMed

    Wijdeven, Ruud H; Jongsma, Marlieke L M; Neefjes, Jacques; Berlin, Ilana

    2015-12-01

    Endosomes shuttle select cargoes between cellular compartments and, in doing so, maintain intracellular homeostasis and enable interactions with the extracellular space. Directionality of endosomal transport critically impinges on cargo fate, as retrograde (microtubule minus-end directed) traffic delivers vesicle contents to the lysosome for proteolysis, while the opposing anterograde (plus-end directed) movement promotes recycling and secretion. Intriguingly, the endoplasmic reticulum (ER) is emerging as a key player in spatiotemporal control of late endosome and lysosome transport, through the establishment of physical contacts with these organelles. Earlier studies have described how minus-end-directed motor proteins become discharged from vesicles engaged at such contact sites. Now, Raiborg et al. implicate ER-mediated interactions, induced by protrudin, in loading plus-end-directed motor kinesin-1 onto endosomes, thereby stimulating their transport toward the cell's periphery. In this review, we recast the prevailing concepts on bidirectional late endosome transport and discuss the emerging paradigm of inter-compartmental regulation from the ER-endosome interface viewpoint. PMID:26440125

  9. Present statue of Japanese ERS-1 Project

    NASA Technical Reports Server (NTRS)

    Ishiwada, Yasufumi; Nemoto, Yoshiaki

    1986-01-01

    Earth Resources Satellite 1 (ERS-1) will be launched in the FY 1990 with the H-1 rocket from Tanegashima Space Center. ERS-1 will seek to firmly establish remote sensing technologies from space by using synthetic aperture radar and optical sensors, as well as primarily exploring for non-renewable resources and also monitoring for land use, agriculture, forestry, fishery, conservation of environment, prevention of disasters, and surveillance of coastal regions. ERS-1 is a joint project in which the main responsibility for the development of the mission equipment is assumed by the Agency of Industrial Science and Technology, MITI, and the Technology Research Association of Resources Remote Sensing System, while that for the satellite itself and launching rocket is assumed by the Science and Technology Agency (STA) and the National Space Development Agency (NASDA). In relation to this project, users have maintained a close working relationship with the manufacturers after submitting their requirements in 1984 on the specifications of the mission equipments. This missions parameters are outlined.

  10. Low-temperature specific heat of magnetic superconductors Dy0.6Y0.4Rh3.85Ru0.15B4 and Dy0.6Y0.4Rh4B4

    NASA Astrophysics Data System (ADS)

    Terekhov, A. V.; Zolochevskii, I. V.; Ishchenko, L. A.; Zaleski, A.; Khlybov, E. P.; Lachenkov, S. A.

    2016-03-01

    Specific heat CM(T) of polycrystalline Dy0.6Y0.4Rh4B4 and Dy0.6Y0.4Rh3.85Ru0.15B4 was studied in the temperature range of 0.5-9 K and magnetic fields 0-10 kOe for the first time. It was found that the λ-anomaly in the specific heat exists at Tc ≈ 6 K for Dy0.6Y0.4Rh4B4 and at Tc ≈ 6.6 K for Dy0.6Y0.4Rh3.85Ru0.15B4. It is suppressed in a magnetic field and shifted to lower temperatures. Partial substitution of Rh by Ru enhances superconductivity, presumably, due to stronger inner magnetism of the dysprosium sublattice in Dy0.6Y0.4Rh4B4 as compared with Dy0.6Y0.4Rh3.85Ru0.15B4. Furthermore, it was observed that the molar heat capacity CM(T) of Dy0.6Y0.4Rh3.85Ru0.15B4 increases with decreasing temperature for T < 4 K. In Dy0.6Y0.4Rh4B4, an increase in CM(T) with decreasing temperature is accompanied by the appearance of a maximum at Tmax = 1.5 K, which might be a manifestation of the magnetic phase transition in the dysprosium subsystem at this temperature.

  11. Magnetic, Caloric and Crystallographic Properties of Dy5(SixGe1-x)4 Alloys

    SciTech Connect

    Vitaliy Vladislavovich Ivchenko

    2002-07-19

    Polycrystals of the intermetallic compound of the Dy{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} system, where x = 0, 0.25, 0.5, 0.625, 0.675, 0.725, 0.75, 0.775, 0.825, 0.875, and 1, have been prepared by electric-arc-melting on water-cooled copper hearth in an argon atmosphere. A study of phase relationships and crystallography in the pseudobinary system Dy{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} using X-ray powder diffraction data and optical metallography was completed. It revealed that silicides in the composition range from 0.825 to 1 crystallize in the Gd{sub 5}Si{sub 4}-type crystal structure: germanides in the composition range from 0 to 0.625 crystallize in the Sm{sub 5}Ge{sub 4}-type structure, and alloys with intermediate composition range from 0.675 to 0.775 crystallize in the monoclinic Gd{sub 5}Si{sub 2}Ge{sub 2}-type structure. The -{Delta}S{sub m} values were determined from magnetization measurements for 7 alloys. The alloys with a monoclinic crystal structure which belong to an intermediate phase region have large MCE value, which exceeds those observed in the other two phase regions by 300 to 500%. The nature of the observed magnetic and structural transformations in the Dy{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} system seems to be similar with those reported for the Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} system. However, the interval and concentration range of three different phase regions in the Dy{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} system are different from that observed in Gd-based alloys. A non-collinear ordering of magnetic moments at low temperature was observed for the alloys with monoclinic crystal structure. The Dy{sub 5}Si{sub 3}Ge alloy exhibited FM phase transition below Curie temperature. A series of magnetic transitions were observed at low temperature in the Dy{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} alloys. The number of transitions increased and the magnetization decreased with increasing germanium content in the alloys. The -{Delta}S{sub m} and

  12. The role of ER stress in lipid metabolism and lipotoxicity.

    PubMed

    Han, Jaeseok; Kaufman, Randal J

    2016-08-01

    The endoplasmic reticulum (ER) is a cellular organelle important for regulating calcium homeostasis, lipid metabolism, protein synthesis, and posttranslational modification and trafficking. Numerous environmental, physiological, and pathological insults disturb ER homeostasis, referred to as ER stress, in which a collection of conserved intracellular signaling pathways, termed the unfolded protein response (UPR), are activated to maintain ER function for cell survival. However, excessive and/or prolonged UPR activation leads to initiation of self-destruction through apoptosis. Excessive accumulation of lipids and their intermediate products causes metabolic abnormalities and cell death, called lipotoxicity, in peripheral organs, including the pancreatic islets, liver, muscle, and heart. Because accumulating evidence links chronic ER stress and defects in UPR signaling to lipotoxicity in peripheral tissues, understanding the role of ER stress in cell physiology is a topic under intense investigation. In this review, we highlight recent findings that link ER stress and UPR signaling to the pathogenesis of peripheral organs due to lipotoxicity. PMID:27146479

  13. Ternary system Er-Ni-In at T=870 K

    SciTech Connect

    Dzevenko, M.; Tyvanchuk, Yu.; Bratash, L.; Zaremba, V.; Havela, L.; Kalychak, Ya.

    2011-10-15

    Isothermal section of the Er-Ni-In system at T=870 K was constructed by means of X-ray powder diffraction and EDX-analyses. Nine ternary compounds, namely ErNi{sub 9}In{sub 2} (YNi{sub 9}In{sub 2}-type), Er{sub 1-1.22}Ni{sub 4}In{sub 1-0.78} (MgCu{sub 4}Sn-type), Er{sub 10}Ni{sub 9.07}In{sub 20} (Ho{sub 10}Ni{sub 9}In{sub 20}-type), ErNi{sub 1-0.60}In{sub 1-1.40} (ZrNiAl-type), Er{sub 2}Ni{sub 2}In (Mn{sub 2}AlB{sub 2}-type), Er{sub 2}Ni{sub 1.78}In (Mo{sub 2}FeB{sub 2}-type), Er{sub 5}Ni{sub 2}In{sub 4} (Lu{sub 5}Ni{sub 2}In{sub 4}-type), Er{sub 5}Ni{sub 2}In (Mo{sub 5}SiB{sub 2}-type), and Er{sub 13.53}Ni{sub 3.14}In{sub 3.33} (Lu{sub 14}Co{sub 2}In{sub 3}-type), exist in the Er-Ni-In system at this temperature. The substitution of Ni for In was observed for ErNi{sub 1-0.60}In{sub 1-1.40} and In for Er in the case of related compounds ErNi{sub 2} and ErNi{sub 4}In. Er can enter NiIn (CoSn-type) leading to including-substitution type of compound Er{sub 0-0.12}NiIn{sub 1-0.89}. Basic magnetic properties of the Er{sub 0.04}NiIn{sub 0.97}, ErNi{sub 2}, Er{sub 0.9}Ni{sub 2}In{sub 0.1}, and ErNi{sub 4}In phases were inspected. Electrical-resistivity studies were performed on the ErNiIn, ErNi{sub 0.9}In{sub 1.1}, and ErNi{sub 4}In phases. - Graphical Abstract: Phase relations in the ternary system Er-Ni-In have been established for the isothermal section at T=870 K based on X-ray phase and EDX-analyses. Nine ternary compounds were observed. Highlights: > Isothermal section of Er-Ni-In system at T=870 K was constructed. > Nine ternary compounds were detected. > Basic magnetic properties of Er{sub 0.04}NiIn{sub 0.97} and ErNi{sub 4}In phases were inspected.

  14. Tamoxifen Action in ER-Negative Breast Cancer

    PubMed Central

    Manna, Subrata; Holz, Marina K.

    2016-01-01

    Breast cancer is a highly heterogeneous disease. Tamoxifen is a selective estrogen receptor (ER) modulator and is mainly indicated for the treatment of breast cancer in postmenopausal women and postsurgery neoadjuvant therapy in ER-positive breast cancers. Interestingly, 5–10% of the ER-negative breast cancers have also shown sensitivity to tamoxifen treatment. The involvement of molecular markers and/or signaling pathways independent of ER signaling has been implicated in tamoxifen sensitivity in the ER-negative subgroup. Studies reveal that variation in the expression of estrogen-related receptor alpha, ER subtype beta, tumor microenvironment, and epigenetics affects tamoxifen sensitivity. This review discusses the background of the research on the action of tamoxifen that may inspire future studies to explore effective therapeutic strategies for the treatment of ER-negative and triple-negative breast cancers, the latter being an aggressive disease with worse clinical outcome. PMID:26989346

  15. Diffusion processes in hot-deformed Nd-Fe-B magnets with DyF3 additions

    NASA Astrophysics Data System (ADS)

    Sawatzki, Simon; Dirba, Imants; Wendrock, Horst; Schultz, Ludwig; Gutfleisch, Oliver

    2014-05-01

    Nd-Fe-B melt spun ribbons have been hot-compacted and subsequently die-upset together with DyF3 in order to increase coercivity in nanocrystalline hot-deformed magnets. Magnetic measurements reveal enhanced coercivities for low and reduced coercivities for high Dy-fractions. This behaviour is due to a superposition of the formation of (Dy,Nd)2Fe14B and non-magnetic Dy and Nd fluoride and oxide phases. Energy dispersive and wavelength dispersive X-ray elemental maps verified this feature. Heat treatments at 600 °C induce a strong F diffusion along the flake boundaries without inducing grain growth. This diffusion is correlated with the changes in magnetic properties.

  16. Large-scale micromagnetic simulation of Nd-Fe-B sintered magnets with Dy-rich shell structures

    NASA Astrophysics Data System (ADS)

    Oikawa, T.; Yokota, H.; Ohkubo, T.; Hono, K.

    2016-05-01

    Large-scale micromagnetic simulations have been performed using the energy minimization method on a model with structural features similar to those of Dy grain boundary diffusion (GBD)-processed sintered magnets. Coercivity increases as a linear function of the anisotropy field of the Dy-rich shell, which is independent of Dy composition in the core as long as the shell thickness is greater than about 15 nm. This result shows that the Dy contained in the initial sintered magnets prior to the GBD process is not essential for enhancing coercivity. Magnetization reversal patterns indicate that coercivity is strongly influenced by domain wall pinning at the grain boundary. This observation is found to be consistent with the one-dimensional pinning theory.

  17. The effect of boron doping on crystal structure, magnetic properties and magnetocaloric effect of DyCo2

    DOE PAGESBeta

    Wang, C. L.; Liu, J.; Mudryk, Y.; Gschneidner, Jr., K. A.; Long, Y.; Pecharsky, V. K.

    2015-12-19

    The magnetic properties and magnetic entropy changes of DyCo2Bx (x=0, 0.05, 0.1, and 0.2) alloys were investigated. The Curie temperature (TC) increases with increasing B concentration. The frequency dependence of ac magnetic susceptibility of DyCo2 caused by the narrow domain wall pinning effect is depressed by B doping, but the coercivity and the magnetic viscosity are prominently increased in the B doped alloys. The magnetic transition nature of DyCo2Bx changes from the first-order to the second-order with increasing x, which leads to the decrease of the maximum magnetic entropy change. Furthermore, the relative cooling power (RCP) of DyCo2 and themore » B doped alloys remains nearly constant.« less

  18. The effect of boron doping on crystal structure, magnetic properties and magnetocaloric effect of DyCo2

    SciTech Connect

    Wang, C. L.; Liu, J.; Mudryk, Y.; Gschneidner, Jr., K. A.; Long, Y.; Pecharsky, V. K.

    2015-12-19

    The magnetic properties and magnetic entropy changes of DyCo2Bx (x=0, 0.05, 0.1, and 0.2) alloys were investigated. The Curie temperature (TC) increases with increasing B concentration. The frequency dependence of ac magnetic susceptibility of DyCo2 caused by the narrow domain wall pinning effect is depressed by B doping, but the coercivity and the magnetic viscosity are prominently increased in the B doped alloys. The magnetic transition nature of DyCo2Bx changes from the first-order to the second-order with increasing x, which leads to the decrease of the maximum magnetic entropy change. Furthermore, the relative cooling power (RCP) of DyCo2 and the B doped alloys remains nearly constant.

  19. The effect of boron doping on crystal structure, magnetic properties and magnetocaloric effect of DyCo2

    NASA Astrophysics Data System (ADS)

    Wang, C. L.; Liu, J.; Mudryk, Y.; Gschneidner, K. A.; Long, Y.; Pecharsky, V. K.

    2016-05-01

    The magnetic properties and magnetic entropy changes of DyCo2Bx (x=0, 0.05, 0.1, and 0.2) alloys were investigated. The Curie temperature (TC) increases with increasing B concentration. The frequency dependence of ac magnetic susceptibility of DyCo2 caused by the narrow domain wall pinning effect is depressed by B doping, but the coercivity and the magnetic viscosity are prominently increased in the B doped alloys. The magnetic transition nature of DyCo2Bx changes from the first-order to the second-order with increasing x, which leads to the decrease of the maximum magnetic entropy change. However, the relative cooling power (RCP) of DyCo2 and the B doped alloys remains nearly constant.

  20. Intensive emission of Dy3+ in NaGd(PO3)4 for Hg-free lamps application.

    PubMed

    Zhong, Jiuping; Liang, Hongbin; Han, Bing; Tian, Zifeng; Su, Qiang; Tao, Ye

    2008-05-12

    The phosphor NaGd(PO(3))(4):Dy(3+) was synthesized by solid-state reaction technique at high temperature. The vacuum ultraviolet (VUV)-UV excitation spectra and visible emission spectra under VUV/UV excitation were investigated. The sample NaGd(PO(3))(4):Dy(3+) showed suitable spectroscopic characteristics such as broad and strong absorption around 172 nm, intensive emission with the chromaticity coordinates (0.33, 0.38) in warm-white light region. Additionally, this efficient white-emitting phosphor is activated by a single Dy(3+) ion and with a lower preparation temperature, which tend to decrease the consumption of rare earth resource and energy. Therefore, the phosphor NGP:Dy(3+) may be considered as a suitable candidate for Hg-free lamps application. PMID:18545456

  1. VizieR Online Data Catalog: Optical and UV photometry of SN 2013dy (Zhai+, 2016)

    NASA Astrophysics Data System (ADS)

    Zhai, Q.; Zhang, J.-J.; Wang, X.-F.; Zhang, T.-M.; Liu, Z.-W.; Brown, P. J.; Huang, F.; Zhao, X.-L.; Chang, L.; Yi, W.-M.; Wang, C.-J.; Xin, Y.-X.; Wang, J.-G.; Lun, B.-L.; Zhang, X.-L.; Fan, Y.-F.; Zheng, X.-M.; Bai, J.-M.

    2016-08-01

    SN2013dy, an Type Ia supernova (SNIa), was discovered at roughly a magnitude of ~17.2mag on UT July 10.45 2013 (Universal Time) in an unfiltered image of the galaxy NGC7250 by the Lick observatory supernova search (Casper et al., 2013CBET.3588....1C). Our first observation of SN 2013dy is in spectroscopy on 2013 July 14 (Zhang & Wang 2013CBET.3394....1Z; 4.76days after the first light and published in Zheng et al. 2013ApJ...778L..15Z) with the Yunnan Faint Object Spectrograph and Camera (YFOSC) mounted at the Li-Jiang 2.4m Telescope (LJT) of Yunnan Observatories (YNAO), China. About two weeks later, we started to monitor this transient intensively at LJT in both ground-based UBVRI photometry and spectroscopy spanning from t~+0 to t~+180days. Ten local standard stars (see Table1 in the paper) in the field of SN2013dy are used to transform the instrumental magnitudes of SN2013dy to the standard Johnson UBV and Kron-Cousins RI system, as listed in Table2. Optical photometry data are also collected with the Tsinghua-NAOC 0.8m telescope (TNT) at Xing-Long Observation of National Astronomical Observatories (NAOC), China, from t~-2days to t~+150days. Additionally, three spectra were obtained at the Xing-Long 2.16 m telescope (hereafter XLT) with the Bei-Jing Faint Object Spectrograph and Camera (BFOSC). Furthermore, this target was also observed by the Ultra-Violet/Optical Telescope (UVOT) on board the Swift satellite. The Swift observatory began observing SN 2013dy on 2013 July 17.09, about 10days (t~-10days) before the B band maximum, and continued for approximately 26days (t~+15days). These photometric observations are performed in three UV filters (uvw2, uvm2, and uvw1) and three broadband optical filters (uu, bb, and vv). Table3 lists the final UVOT UV/optical magnitudes of SN2013dy. (2 data files).

  2. Origin of enhanced multiferroic properties in Dy and Co co-doped BiFeO3 ceramics

    NASA Astrophysics Data System (ADS)

    Yoo, Y. J.; Hwang, J. S.; Lee, Y. P.; Park, J. S.; Rhee, J. Y.; Kang, J.-H.; Lee, K. W.; Lee, B. W.; Seo, M. S.

    2015-01-01

    Structural, magnetic and ferroelectric properties of polycrystalline BiFeO3, Bi0.9Dy0.1FeO3, BiFe0.97Co0.03O3 and Bi0.9Dy0.1Fe0.97Co0.03O3, which were prepared by solid-state method, have been investigated. The X-ray diffraction (XRD) patterns reveal that all the samples are in single phase and show rhombohedrally distorted perovskite structure with R3c space group. Both XRD and Raman-scattering studies show that Dy and Co co-doped sample has a compressive lattice distortion induced by co-substitution of Dy and Co ions at the A and the B sites, respectively. Dy and Co co-doping favors weak ferromagnetism ordering with evident magnetic hysteresis loop and enhances magnetization values at room temperature. Ferroelectric hysteresis loop for Dy and Co co-doped sample shows the nearly saturated polarization at 40 kV/cm and large remnant polarization. Dy dopant is prominent in the reduced leakage current density, while Co dopant is remarkable in the improved remnant magnetization in Bi0.9Dy0.1Fe0.97Co0.03O3 ceramic. By using a simple model, it was found that the anharmonicity of canted spiral cycloidal spin structure was responsible for the weak ferromagnetism of pure BiFeO3, and the enhanced magnetization in Co-doped sample was attributed to the transition from the incommensurate cycloidal spiral spin structure towards the G-type canted collinear antiferromagnetic structure.

  3. Production and validation of model iron-tannate dyed textiles for use as historic textile substitutes in stabilisation treatment studies

    PubMed Central

    2012-01-01

    Background For millennia, iron-tannate dyes have been used to colour ceremonial and domestic objects shades of black, grey, or brown. Surviving iron-tannate dyed objects are part of our cultural heritage but their existence is threatened by the dye itself which can accelerate oxidation and acid hydrolysis of the substrate. This causes many iron-tannate dyed textiles to discolour and decrease in tensile strength and flexibility at a faster rate than equivalent undyed textiles. The current lack of suitable stabilisation treatments means that many historic iron-tannate dyed objects are rapidly crumbling to dust with the knowledge and value they hold being lost forever. This paper describes the production, characterisation, and validation of model iron-tannate dyed textiles as substitutes for historic iron-tannate dyed textiles in the development of stabilisation treatments. Spectrophotometry, surface pH, tensile testing, SEM-EDX, and XRF have been used to characterise the model textiles. Results On application to textiles, the model dyes imparted mid to dark blue-grey colouration, an immediate tensile strength loss of the textiles and an increase in surface acidity. The dyes introduced significant quantities of iron into the textiles which was distributed in the exterior and interior of the cotton, abaca, and silk fibres but only in the exterior of the wool fibres. As seen with historic iron-tannate dyed objects, the dyed cotton, abaca, and silk textiles lost tensile strength faster and more significantly than undyed equivalents during accelerated thermal ageing and all of the dyed model textiles, most notably the cotton, discoloured more than the undyed equivalents on ageing. Conclusions The abaca, cotton, and silk model textiles are judged to be suitable for use as substitutes for cultural heritage materials in the testing of stabilisation treatments. PMID:22616934

  4. Strategic coating of NdFeB magnets with Dy to improve the coercivity of permanent magnets

    DOE PAGESBeta

    Ucar, Huseyin; Parker, David S.; Nlebedim, I. C.; McCallum, R. W.; McCall, S. K.; Parans Paranthaman, M.

    2015-12-25

    Here, we present a method, supported by theoretical analysis, for optimizing the usage of the critical rare earth element dysprosium in Nd2Fe14B (NdFeB)-based permanent magnets. In this method, we use Dy selectively in locations such as magnet edges and faces, where demagnetization factors are most significant, rather than uniformly throughout the bulk sample. A 200 nm thick Dy film was sputtered onto commercial N-38, NdFeB magnets with a thickness of 3 mm and post-annealed at temperatures from 600 - 700 C. Magnets displayed enhanced coercivities after post-annealing. Furthermore, our experimental results indicate as large as a 5 percent increase inmore » the energy product of NdFeB magnets, achieved for a total Dy weight percentage of 0.06 percent, much less than that used in commercial grade Dy-NdFeB magnets. Finally, by assuming all Dy diffused into NdFeB magnets, the improvement in energy product corresponds to a saving of over 1% Dy (critical element). Magnets manufactured using this technique will therefore be higher performing and significantly less expensive than those made presently.« less

  5. Efficient photoluminescence of Dy{sup 3+} at low concentrations in nanocrystalline ZrO{sub 2}

    SciTech Connect

    Diaz-Torres, L.A.; Rosa, E. de la Salas, P.; Romero, V.H.; Angeles-Chavez, C.

    2008-01-15

    Nanocrystalline ZrO{sub 2}:Dy{sup 3+} were prepared by sol-gel and the structural and photoluminescence properties characterized. The crystallite size ranges from 20 to 50 nm and the crystalline phase is a mixture of tetragonal and monoclinic structure controlled by dopant concentration. Strong white light produced by the host emission band centered at {approx}460 nm and two strong Dy{sup 3+} emission bands, blue (488 nm) and yellow (580 nm), under direct excitation at 350 nm were observed. The highest efficiency was obtained for 0.5 mol% of Dy{sup 3+}. Emission is explained in terms of high asymmetry of the host suggesting that Dy{sup 3+} are substituted mainly into Zr{sup 4+} lattice sites at the crystallite surface. Luminescence quenching is explained in terms of cross-relaxation of intermediate Dy{sup 3+} levels. - Graphical abstract: White light emission from {approx}70 nm ZrO{sub 2}:Dy{sup 3+} nanocrystals. The highest efficiency was obtained for 0.5 mol% of dopant and the dominant crystalline structure was monoclinic.

  6. Electrical and magnetic properties of hot-deformed Nd-Fe-B magnets with different DyF3 additions

    NASA Astrophysics Data System (ADS)

    Sawatzki, Simon; Dirba, Imants; Schultz, Ludwig; Gutfleisch, Oliver

    2013-10-01

    The effect of deformation and DyF3 additions on the electrical resistivity and the magnetic performance has been studied in hot-deformed Nd-Fe-B melt-spun ribbons and correlated with respective microstructures. Despite the nanocrystallinity of hot-compacted magnets, the specific electrical resistivity measured by four-point-method was shown to be comparable with that of sintered magnets. Die-upsetting reduces electrical resistivity within the magnetically hard plane because of an enhanced shape anisotropy of the grains. The addition of DyF3 overcompensates this reduction due to the presence of electrically insulating Dy-F rich inclusions and thus reduces eddy current losses within the magnet. Magnetic measurements reveal an increase in coercivity without a change in remanence for die-upset magnets with a total height reduction of 63% and 1.2 wt. % Dy (1.6 wt. %DyF3). Both properties, remanence and coercivity, demonstrate an effective reduction in heavy rare earth Dy for Nd-Fe-B magnets.

  7. BaGdF5:Dy(3+),Tb(3+),Eu(3+) multifunctional nanospheres: paramagnetic, luminescence, energy transfer, and tunable color.

    PubMed

    Guan, Hongxia; Song, Yanhua; Zheng, Keyan; Sheng, Ye; Zou, Haifeng

    2016-05-18

    A series of Dy(3+),Tb(3+) and Eu(3+) singly, doubly or triply doped BaGdF5 phosphors were synthesized by a one-step hydrothermal method with l-arginine, and their energy transfer, migrations and multicolored luminescence properties were investigated in detail. The as-prepared Dy(3+),Tb(3+) or Eu(3+) doped samples showed strong blue, green and red emission, respectively. Different hues of green and red light were obtained by co-doped Dy(3+),Tb(3+) and Tb(3+),Eu(3+) in the BaGdF5 host, respectively. More significantly, in the Dy(3+),Tb(3+),Eu(3+) tri-doped BaGdF5 phosphors, colors changed from yellow green to orange red by adjusting the doping concentration of Eu(3+). Energy migrations from Dy(3+) to Tb(3+) and from Tb(3+) to Eu(3+) are reported in detail. Furthermore, the obtained samples exhibit paramagnetic properties at room temperature and low temperature. It is obvious that these Dy(3+), Tb(3+), Eu(3+) singly or doubly or triply doped BaGdF5 nanomaterials with tunable multicolored luminescence properties may have potential applications in the fields of full-color displays, biological labels and bio-separation. PMID:27146322

  8. Surface photo-discoloration and degradation of dyed wood veneer exposed to different wavelengths of artificial light

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Shao, Lingmin; Gao, Jianmin; Guo, Hongwu; Chen, Yao; Cheng, Qingzheng; Via, Brian K.

    2015-03-01

    The surface of dyed wood is prone to discoloration when exposed to light irradiation which significantly decreases its decorative effect and shortens its service life. The influence of light wavelength exposure to the surface of dyed wood was investigated to study the effect on discoloration and degradation. Acid Blue V and Acid Red GR dyed wood veneers were subjected to light exposure with different wavelengths from the UV to visible region (254-420 nm). Results showed that the surface discoloration of dyed wood was linearly related to lignin concentration and dyes degradation and the consequent transformation of chromophoric groups such as aromatic (Cdbnd C) and carbonyl (Cdbnd O) through methoxy reaction. The dyes, lignin and some active constituents were degraded severely, even at short exposures. Acid Blue V dyed wood exhibited greater discoloration than the Acid Red GR treatment. The reflectance and K/S absorption curve showed a hypochromic effect on the dyed wood surface. The dyes and wood chemical structure played a complex and combined role on the selective absorption of different wavelengths of light. The color change rate was apparent with 254 nm exposure in the initial stages, but a greater discoloration rate occurred on the samples irradiated at 313 and 340 nm than at 254 and 420 nm with the time prolonged. The degradation rate and degree of discoloration correlated well with the light energy and wavelength.

  9. Optical thermometry based on luminescence behavior of Dy3+-doped transparent LaF3 glass ceramics

    NASA Astrophysics Data System (ADS)

    Bu, Y. Y.; Cheng, S. J.; Wang, X. F.; Yan, X. H.

    2015-11-01

    Dy3+-doped transparent LaF3 glass ceramics were fabricated, and its structures of resulting glass ceramics are studied by the X-ray diffraction and transmission electron microscopy. Optical temperature sensing of the resulting glass ceramics in the temperature range from 298 to 523 K is studied based on the down-conversion luminescence of Dy3+ ion. By using fluorescence intensity ratio method, the 4I15/2 and 4F9/2 of Dy3+ ions are verified as thermally coupled levels. A minimum S R = 1.16 × 10-4 K-1 is obtained at T = 294 K. By doping Eu3+ ion, the overall emission color of Eu3+-Dy3+ co-doped transparent glass ceramics can be tuned from white to yellow with the temperature increase through energy transfer between Eu3+ and Dy3+. Additionally, the thermal stability of the Dy3+ single-doped transparent glass ceramics becomes higher after doping Eu3+ ion.

  10. Study of crystal-field excitations and infrared active phonons in the multiferroic hexagonal DyMnO3

    NASA Astrophysics Data System (ADS)

    Jandl, S.; Mansouri, S.; Vermette, J.; Mukhin, A. A.; Ivanov, V. Yu; Balbashov, A.; Orlita, M.

    2013-11-01

    In hexagonal DyMnO3, Dy3+ crystal-field excitations are studied as a function of temperature and applied magnetic field. They are complemented with the measurements of infrared active phonon frequency shifts under applied magnetic field at T = 4.2 K. Between TN = 68 K and T = 10 K, the absence of Dy3+ Kramers doublet splittings at either the C3 or the C3v site symmetries indicates that the Mn3+ magnetic order effective exchange field has no component parallel to the c-axis at either site. Below T = 10 K, the ground state Kramers doublet splits under the Dy3+ internal effective field as well as the applied magnetic field. Also, relatively strong infrared active phonon energy shifts are observed in magneto-infrared reflectance measurements at T = 4.2 K, allowing the calculation of the induced electric polarization changes as a function of the applied magnetic field. Such changes are associated with a large magnetoelectric effect in DyMnO3, arising from a charge transfer between Dy3+ and apical oxygen ions.

  11. Simultaneous enhancement of magnetic and ferroelectric properties in Dy and Cr co-doped BiFeO3 nanoparticles.

    PubMed

    Mao, Weiwei; Wang, Xingfu; Chu, Liang; Zhu, Yiyi; Wang, Qi; Zhang, Jian; Yang, Jianping; Li, Xing'ao; Huang, Wei

    2016-03-01

    Multiferroic BiFeO3 (BFO), Bi0.95Dy0.05FeO3 and Bi0.95Dy0.05Fe0.95Cr0.05O3 samples were successfully synthesized by a carbon microsphere-assisted sol-gel (CSG) method. X-ray diffraction analysis confirmed a lattice distortion from a rhombohedral structure to a tetragonal structure upon doping Dy and Cr in BFO. The morphology of BFO and doped BFO could be effectively controlled to form nanoparticles, due to the nucleation sites of the carbon microspheres. The co-doping of Dy and Cr in BFO had a significant improvement effect on the magnetic properties, with the remnant magnetization being 0.557 emu g(-1), due to the structural phase transition, size effects and the strong ferromagnetic interaction between Fe(3+)-O-Cr(3+) ions arising from Cr substitution. Meanwhile, the doping of Dy into BFO effectively reduced the leakage current and enhanced the ferroelectric properties. The simultaneous enhancement of magnetic and ferroelectric properties shows the great potential application of Dy- and Cr-co-doped BFO in future multifunctional devices. PMID:26862599

  12. Investigation of Cu Doping, Morphology and Annealing Effects on Structural and Optical Properties of ZnO:Dy Nanostructures.

    PubMed

    Najafi, Mehrdad

    2016-05-01

    Dysprosium (Dy) doped ZnO nanosheets and nanorods were synthesized by hydrothermal method. Effects of Cu doping, morphology and annealing in Oxygen ambient on structural and optical properties of ZnO nanostructures were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectra (DRS) and photoluminescence (PL) spectroscopy. This study recommends that both of intrinsic and extrinsic defects facilitate energy transfer (ET) from the ZnO host to Dy(3+) ions and consequently have an effective role on producing intense Dy emissions at indirect excitation. The results also revealed that annealing process improved the crystal structure of ZnO nanorods due to decrease of surface; however decreased ET and Dy emissions because of diminishing in oxygen vacancy. In addition, as a result of increasing of surface area in nanorods compared to nanosheets, the oxygen vacancies and ET were enhanced. Moreover the results exhibited that electrical and optical properties of ZnO:Dy can be tuned by various amount of Dy concentrations and also Cu doping. PMID:26798063

  13. White Light Emissive Dy(III) Single-Molecule Magnets Sensitized by Diamagnetic [Co(III) (CN)6 ](3-) Linkers.

    PubMed

    Chorazy, Szymon; Rams, Michał; Nakabayashi, Koji; Sieklucka, Barbara; Ohkoshi, Shin-Ichi

    2016-05-23

    The self-assembly of Dy(III) -3-hydroxypyridine (3-OHpy) complexes with hexacyanidocobaltate(III) anions in water produces cyanido-bridged {[Dy(III) (3-OHpy)2 (H2 O)4 ] [Co(III) (CN)6 ]}⋅H2 O (1) chains. They reveal a single-molecule magnet (SMM) behavior with a large zero direct current (dc) field energy barrier, ΔE=266(12) cm(-1) (≈385 K), originating from the single-ion property of eight-coordinated Dy(III) of an elongated dodecahedral geometry, which are embedded with diamagnetic [Co(III) (CN)6 ](3-) ions into zig-zag coordination chains. The SMM character is enhanced by the external dc magnetic field, which results in the ΔE of 320(23) cm(-1) (≈460 K) at Hdc =1 kOe, and the opening of a butterfly hysteresis loop below 6 K. Complex 1 exhibits white Dy(III) -based emission realized by energy transfer from Co(III) and 3-OHpy to Dy(III) . Low temperature emission spectra were correlated with SMM property giving the estimation of the zero field ΔE. 1 is a unique example of bifunctional magneto-luminescent material combining white emission and slow magnetic relaxation with a large energy barrier, both controlled by rich structural and electronic interplay between Dy(III) , 3-OHpy, and [Co(III) (CN)6 ](3-) . PMID:26990787

  14. White-light emission from Li2Sr1-3 x/2Dy x SiO4 phosphors

    NASA Astrophysics Data System (ADS)

    Sun, Xin-Yuan; Lin, Liang-Wu; Wang, Wen-Feng; Zhang, Jun-Cheng

    2011-07-01

    Li2Sr1-3 x/2Dy x SiO4 phosphors were synthesized at 900°C in the normal atmosphere by a solid-state method. The synthesized phosphors were characterized by X-ray powder diffraction (XRD) and photoluminescence (PL) spectra. The photoluminescence excitation (PLE) spectra show excitation peaks ranging from 300 to 400 nm due to the 4 f-4 f transitions of Dy3+. This mercury-free excitation is useful for solid-state lighting and light-emitting diodes (LEDs). The predominant emission of Dy3+ ions under 349 nm excitation is observed at 479 nm (blue) due to the 4F9/2→6H15/2 transitions and 572 nm (yellow) due to 4F9/2→6H13/2 transitions, respectively. The PL results reveal that the optimal concentration of the Dy3+ ions in Li2Sr1-3 x/2Dy x SiO4 phosphors is x=0.03 mol. The nature of the resonance energy transfer for the Dy3+ ions is confirmed by Huang's rule. Simulation of the white light excited by 349 nm near-ultraviolet (n-UV) light is also performed for its potential for white LEDs.

  15. Luminescence and energy transfer of white emitting phosphor YAl3(BO3)4:Ce3+, Dy3+

    NASA Astrophysics Data System (ADS)

    Zhou, Fen; Wang, Di; Cao, He-ying; Li, Jing; Song, Hui-ling; Li, Pan-lai; Wang, Zhi-jun; Zhang, Kun; Pang, Li-bin

    2015-03-01

    A white emitting phosphor of YAl3(BO3)4:Ce3+, Dy3+ is synthesized by a solid state reaction, and its luminescent properties are investigated. Its phase formation is carried out with X-ray powder diffraction analysis, and there is no crystalline phase other than YAl3(BO3)4. YAl3(BO3)4:Ce3+ can produce 422 nm blue emission under 367 nm excitation. The emission spectrum of YAl3(BO3)4:Dy3+ shows several emission peaks under 350 nm excitation, and the peaks locate at 485 nm, 575 nm and 668 nm, respectively. Emission intensities of Ce3+ and Dy3+ in YAl3(BO3)4 are influenced by their concentrations, and the concentration quenching effect is observed. Energy transfer from Ce3+ to Dy3+ in YAl3(BO3)4 is validated and proved to be a resonant type via a quadrupole-quadrupole interaction, and the emission color can be tuned from blue to white by tuning the ratio of Ce3+/Dy3+. Moreover, the critical distance ( R c) of Ce3+ to Dy3+ in YAl3(BO3)4 is calculated to be 1.904 nm.

  16. Strategic coating of NdFeB magnets with Dy to improve the coercivity of permanent magnets

    SciTech Connect

    Ucar, Huseyin; Parker, David S.; Nlebedim, I. C.; McCallum, R. W.; McCall, S. K.; Parans Paranthaman, M.

    2015-12-25

    Here, we present a method, supported by theoretical analysis, for optimizing the usage of the critical rare earth element dysprosium in Nd2Fe14B (NdFeB)-based permanent magnets. In this method, we use Dy selectively in locations such as magnet edges and faces, where demagnetization factors are most significant, rather than uniformly throughout the bulk sample. A 200 nm thick Dy film was sputtered onto commercial N-38, NdFeB magnets with a thickness of 3 mm and post-annealed at temperatures from 600 - 700 C. Magnets displayed enhanced coercivities after post-annealing. Furthermore, our experimental results indicate as large as a 5 percent increase in the energy product of NdFeB magnets, achieved for a total Dy weight percentage of 0.06 percent, much less than that used in commercial grade Dy-NdFeB magnets. Finally, by assuming all Dy diffused into NdFeB magnets, the improvement in energy product corresponds to a saving of over 1% Dy (critical element). Magnets manufactured using this technique will therefore be higher performing and significantly less expensive than those made presently.

  17. On the Use of an ER-213 Detonator to Establish a Baseline for the ER-486

    SciTech Connect

    Thomas, Keith A.; Liechty, Gary H.; Jaramillo, Dennis C.; Munger, Alan C.; McHugh, Douglas C.; Kennedy, James E.

    2014-08-19

    This report documents a series of tests using a TSD-115 fireset coupled with an ER-213, a gold exploding bridgewire (EBW) detonator. These tests were designed to fire this EBW with a smaller fireset to obtain current and voltage data as well as timing information at voltage levels below, above, and throughout the threshold firing region. This study could then create a database for comparison to our current ER-486 EBW development, which is designed to be a lower voltage (<500V) device.

  18. Bulk Er:YAP and Er:Yb:YAP optical emission studies for eyesafe laser applications

    NASA Astrophysics Data System (ADS)

    Georgiou, Efstratios; Boquillon, Jean-Pierre; Musset, Olivier

    2012-06-01

    Emission and excitation spectra of Er-doped YAP crystals reveal a broad emission band in the eyesafe region with peaks around 1545-nm and 1608-nm and pump-bands suitable for common 800-nm and 970-nm diode lasers, suggesting YAP as a candidate crystalline host for diode-pumped laser in the 1.5-μm eyesafe regime. Erbium-doped YAP-crystal results are comparable with analogous measurements on Er:Yb:YAG, which has already demostrated efficient lasing action in the eyesafe region.

  19. Structure and electronic properties of Dy@C 82 studied by UV-VIS absorption, X-ray powder diffraction and XAFS

    NASA Astrophysics Data System (ADS)

    Iida, S.; Kubozono, Y.; Slovokhotov, Y.; Takabayashi, Y.; Kanbara, T.; Fukunaga, T.; Fujiki, S.; Emura, S.; Kashino, S.

    2001-04-01

    Two isomers of Dy@C 82 were separated by high performance liquid chromatography (HPLC), and their UV-VIS absorption spectra were measured to characterize these isomers. The crystalline powder of Dy@C 82 was obtained by removing the solvent (toluene) at 250°C under vacuum. The X-ray diffraction pattern can be indexed with fcc crystal lattice, as that in La@C 82. The lattice constant a at 298 K, 15.86(1) Å, is close to that of La@C 82, 15.78 Å. The distances between Dy and the first and second nearest C atoms are determined to be 2.52(2) and 2.86(2) Å, respectively, on the basis of Dy L III-edge EXAFS. The XANES shows that the valence of the Dy atom in Dy@C 82 is +3.

  20. Single-molecule magnet behavior in an octanuclear dysprosium(iii) aggregate inherited from helical triangular Dy3 SMM-building blocks.

    PubMed

    Zhang, Li; Zhang, Peng; Zhao, Lang; Wu, Jianfeng; Guo, Mei; Tang, Jinkui

    2016-06-28

    An unprecedented octanuclear dysprosium(iii) cluster with the formula [Dy8L6(μ3-OH)4(μ2-CH3O)2(CH3OH)6(H2O)2]·6H2O·10CH3OH·2CH3CN () based on a nonlinearly tritopic aroylhydrazone ligand H3L has been isolated, realizing the successful linking of pairwise interesting triangular Dy3 SMMs. It is noteworthy that two enantiomers (Λ and Δ configurations) individually behaving as a coordination-induced chirality presented in the Dy3 helicate are connected in the meso Dy8 cluster. Remarkably, alternating-current magnetic susceptibility measurements revealed that the Dy8 cluster shows typical SMM behavior inherited from its Dy3 helical precursor. It is one of the rare polynuclear Lnn SMMs (n > 7) under zero dc field. PMID:27231152

  1. Concentration dependent spectroscopic properties of Dy3+ ions doped boro-phosphate glasses

    NASA Astrophysics Data System (ADS)

    Mariyappan, M.; Marimuthu, K.

    2016-05-01

    Dy3+ ions doped boro-phosphate glasses have been synthesized by melt quenching method and characterized through FTIR, absorption and luminescence spectral measurements. The presence of various stretching and bending vibrations of different borate and phosphate groups were identified from the FTIR spectra. In order to examine the electronic band structure of the studied glasses, Optical energy gap (Eopt) and Urbach energy (ΔE) values were estimated from the absorption spectra. The Judd-Ofelt (JO) intensity parameters were calculated to examine the symmetry of the ligand environment around the Dy3+ ions site. The emission spectra exhibit two intense emission bands at around 482 nm (blue) and 574 nm (yellow) corresponding to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions respectively. The emission spectra were characterized through Commission International d'Eclairage (CIE) 1931 chromaticity diagram to explore its suitability for WLED applications.

  2. Spectroscopic characteristics of Dy3+ doped Y3Al5O12 transparent ceramics

    NASA Astrophysics Data System (ADS)

    Lupei, A.; Lupei, V.; Gheorghe, C.; Ikesue, A.; Enculescu, M.

    2011-10-01

    The spectroscopic characteristics of Dy3+ in YAG (Y3Al5O12) transparent ceramics prepared by solid state synthesis were investigated, with special attention to the visible (yellow, blue) emissions that could be pumped directly by the new developed blue-violet or near UV laser diodes. The absorption and emission spectra, recorded at different temperatures from 10 to 300 K, were analyzed and relevant new parameters, improved energy level scheme, temperature effects, intensity parameters based on Judd-Ofelt theory and radiative transition rates, branching ratios, etc., were estimated and the data are compared with previous reports on garnet single crystals. The potential of the Dy3+: YAG transparent ceramics for yellow or blue laser emission is discussed.

  3. Investigation on the magnetocaloric effect in RNi2 (R: Dy, tb) melt-spun ribbon

    NASA Astrophysics Data System (ADS)

    de Souza, M. V.

    2016-08-01

    We report a theoretical and experimental investigation on the magnetocaloric properties of the rare earth RNi2 (R=Dy,Tb) in melt-spun ribbon and bulk form. The theoretical calculations were performed using a Hamiltonian model including the Zeeman-exchange interactions and the crystalline electrical field. Thus the magnetocaloric potential was calculated in the easy magnetic axes, in order an average over all of the possible directions. The isothermal entropy-change dependence on temperature calculated was compared with available experimental data for melt-spun ribbon and bulk material. We also investigated, theoretically and experimentally, the behavior of a DyNi2 and TbNi2 composite with optimized molar proportions and discussed this in the context of the optimum regeneration Ericsson cycle.

  4. Phase and amplitude patterns in DySEM mappings of vibrating microstructures

    NASA Astrophysics Data System (ADS)

    Schröter, M.-A.; Sturm, H.; Holschneider, M.

    2013-05-01

    We use a dynamic scanning electron microscope (DySEM) to analyze the movement of oscillating micromechanical structures. A dynamic secondary electron (SE) signal is recorded and correlated to the oscillatory excitation of scanning force microscope (SFM) cantilever by means of lock-in amplifiers. We show, how the relative phase of the oscillations modulate the resulting real part and phase pictures of the DySEM mapping. This can be used to obtain information about the underlying oscillatory dynamics. We apply the theory to the case of a cantilever in oscillation, driven at different flexural and torsional resonance modes. This is an extension of a recent work (Schröter et al 2012 Nanotechnology 23 435501), where we reported on a general methodology to distinguish nonlinear features caused by the imaging process from those caused by cantilever motion.

  5. PREFACE: International Conference on Dynamics of Systems on the Nanoscale (DySoN 2012)

    NASA Astrophysics Data System (ADS)

    Solov'yov, Andrey V.

    2013-06-01

    Conference logo The Second International Conference 'Dynamics of Systems on the Nanoscale' (DySoN 2012) took place in Saint Petersburg, Russia between 30 September and 4 October 2012. The venue was the Courtyard by Marriott St Petersburg Vasilievsky Hotel, 2nd line of Vasilievsky Island 61/30A, 199178. The conference was organized by the Frankfurt Institute for Advanced Studies - Goethe University, A F Ioffe Physical-Technical Institute and Saint Petersburg State Polytechnic University. This DySoN conference has been built upon a series of International Symposia 'Atomic Cluster Collisions: structure and dynamics from the nuclear to the biological scale' (ISACC 2003, ISACC 2007, ISACC 2008, ISACC 2009 and ISACC 2011). During these meetings it has become clear that there is a need for an interdisciplinary conference covering a broader range of topics than just atomic cluster collisions, related to the Dynamics of Systems on a Nanoscale. Therefore, in 2010 it was decided to launch a new conference series under the title 'Dynamics of Systems on the Nanoscale'. The first DySoN conference took place at the National Research Council, Rome, Italy in 2010. The DySoN 2012 is the second conference in this series. The DySoN 2012 Conference promoted the growth and exchange of interdisciplinary scientific information on the structure, formation and dynamics of animate and inanimate matter on the nanometer scale. There are many examples of complex many-body systems of micro- and nanometer scale size exhibiting unique features, properties and functions. These systems may have very different nature and origin, e.g. atomic and molecular clusters, nanoobjects, ensembles of nanoparticles, nanostructures, biomolecules, biomolecular and mesoscopic systems. A detailed understanding of the structure and dynamics of these systems on the nanometer scale is an important fundamental task, the solution of which is necessary in numerous applications of nano- and biotechnology, material science

  6. Modeling the thermoluminescent response of CaSO4:Dy by the MCNPX method.

    PubMed

    Furetta, C; Roman, J; Rivera, T; Azorín, J; Azorín, C G; Vega-Carrillo, H R

    2010-01-01

    This work describes an algorithm for absorbed dose evaluation in the region of X-ray diagnostic energy based on the response of CaSO(4):Dy thermoluminescence powder detectors. The absorbed dose was calculated using Monte Carlo simulation code (MCSC) and then compared to the experimental TLD results for X-rays effective energies (60)Co gamma radiation. In order to study the photon interaction in the matter, a cylindrical model of 1 cm(3) was used. The gamma radiation source was placed at 100 cm to the object; the source is considered as an isotropic source of (60)Co. The energy deposited into the cylindrical model was determined by the Monte Carlo N-particle (MCNPX) method. Measurements of the TL phosphors were obtained by irradiating the powder by gamma radiation. TL glow curve of CaSO(4):Dy after gamma irradiated at a 1 Gy of absorbed dose was then obtained. PMID:20079655

  7. Magnetic properties of YBaCuO ceramics undoped and doped with Ni and Dy

    NASA Astrophysics Data System (ADS)

    Ilonca, Gheorghe; Simon, Simion; Ardelean, Ioan; Redac, Radu; Cozar, Onuc; Barbur, Ioan

    1989-12-01

    Different polycrystalline samples of high-T c superconducting compounds Y Ba 3-xCu 3O 7-δ; Y 1-xDy xBa 2Cu 3O 7-δ and Y 1Ba 2Cu 3-xNi xO 7-δ have been prepared and characterized. They have been investigated by dc magnetic susceptibility and X-ray powder-diffraction pattern. Magnetic susceptibility data show Néel temperature about 200 K and critical temperature between 77-93 K. High-T c superconductivity is not destroyed by the localized magnetic moments of the rare-earth Dy ions, but the copper substitution by nickel determined a gradual diminution of the superconducting phase.

  8. Spin relaxation in antiferromagnetic Fe–Fe dimers slowed down by anisotropic DyIII ions

    PubMed Central

    Klöwer, Frederik; Lan, Yanhua; Clérac, Rodolphe; Wolny, Juliusz A; Schünemann, Volker; Anson, Christopher E

    2013-01-01

    Summary By using Mössbauer spectroscopy in combination with susceptibility measurements it was possible to identify the supertransferred hyperfine field through the oxygen bridges between DyIII and FeIII in a {Fe4Dy2} coordination cluster. The presence of the dysprosium ions provides enough magnetic anisotropy to “block” the hyperfine field that is experienced by the iron nuclei. This has resulted in magnetic spectra with internal hyperfine fields of the iron nuclei of about 23 T. The set of data permitted us to conclude that the direction of the anisotropy in lanthanide nanosize molecular clusters is associated with the single ion and crystal field contributions and 57Fe Mössbauer spectroscopy may be informative with regard to the the anisotropy not only of the studied isotope, but also of elements interacting with this isotope. PMID:24367750

  9. Observation of room temperature saturated ferroelectric polarization in Dy substituted BiFeO3 ceramics

    NASA Astrophysics Data System (ADS)

    Zhang, Shuxia; Wang, Lei; Chen, Yao; Wang, Dongliang; Yao, Yingbang; Ma, Yanwei

    2012-04-01

    High quality Bi1-xDyxFeO3 (0 ≤ x ≤ 0.15) ceramics have been fabricated by sintering Dy-doped BiFeO3 (BFO) precursor powders at a low temperature of 780 °C. The magnetic properties of BFO were improved by the introduction of Dy on the Bi-site. More importantly, well saturated ferroelectric hysteresis loops and polarization switching currents have been observed at room temperature. A large remnant polarization (2Pr) value of 62 μC/cm2 is achieved, which is the highest value reported so far for rare-earth-doped BFO ceramics. Moreover, mechanisms for improved multiferroic properties depending on chemical doping-caused structure evolutions have also been discussed.

  10. Physicochemical characterization of thermally aged Egyptian linen dyed with organic natural dyestuffs

    NASA Astrophysics Data System (ADS)

    Kourkoumelis, N.; El-Gaoudy, H.; Varella, E.; Kovala-Demertzi, D.

    2013-08-01

    A number of organic natural dyestuffs used in dyeing in ancient times, i.e. indigo, madder, turmeric, henna, cochineal, saffron and safflower, have been used to colour Egyptian fabrics based on linen. Their physicochemical properties have been evaluated on thermally aged linen samples. The aged dyed linen samples were thoroughly examined by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and tensile strength and elongation measurements. It was found that, in the molecular level, dyes interact mainly with the cellulose compounds of the aged linen while in the macroscopic level tensile and elongation parameters are altered. Tensile strength is positively related to the dye treatment while elongation depends specifically on the type of the dye used. Results converge that the dyed textiles did indeed play a role as protecting agents affecting strength and reducing thermal deterioration.

  11. YAG:Dy and YAG:Tm Fluorescence Above 1400 C.

    SciTech Connect

    Cates, M.R.

    2003-08-01

    Fluorescence from three samples of YAG:Tm, and three samples of YAG:Dy, with different activator concentrations, was measured for a wide temperature range, extending from room temperature to about 1700 C. Fluorescence lifetimes were measured for emissions at 460 nm from the YAG:Tm and at 453, 480, and 575 nm from YAG:Dy. The measurement system is described, including techniques for accommodating the high background blackbody radiation encountered at these very high temperatures. Data compilations are shown, including the fluorescence lifetimes over the temperature range of the measurement. This study has extended the high-temperature range of phosphor thermometry by approximately 200 C and shown the feasibility of using phosphor materials for very high temperature noncontact thermometry, opening up further applications for engines, materials, high-temperature processing, and related areas.

  12. DyNet: visualization and analysis of dynamic molecular interaction networks

    PubMed Central

    Goenawan, Ivan H.; Lynn, David J.

    2016-01-01

    Summary: The ability to experimentally determine molecular interactions on an almost proteome-wide scale under different conditions is enabling researchers to move from static to dynamic network analysis, uncovering new insights into how interaction networks are physically rewired in response to different stimuli and in disease. Dynamic interaction data presents a special challenge in network biology. Here, we present DyNet, a Cytoscape application that provides a range of functionalities for the visualization, real-time synchronization and analysis of large multi-state dynamic molecular interaction networks enabling users to quickly identify and analyze the most ‘rewired’ nodes across many network states. Availability and Implementation: DyNet is available at the Cytoscape (3.2+) App Store (http://apps.cytoscape.org/apps/dynet). Contact: david.lynn@sahmri.com. Supplementary Information: Supplementary data are available at Bioinformatics online. PMID:27153624

  13. Inter-band B(E2) transitions strengths in 160-170Dy nuclei

    NASA Astrophysics Data System (ADS)

    Vargas, Carlos E.; Velázquez, Víctor; Lerma, Sergio

    2015-01-01

    The rare earth region of the nuclear landscape is characterized by a large collectivity observed. The microscopic studies are difficult to perform in the region due to the enormous size of the valence spaces. The use of symmetries based models avoids that problem, because the symmetry allows to choose the most relevant degrees of freedom for the system under consideration. We present theoretical results for electromagnetic properties in 160-168Dy isotopes employing the pseudo-SU(3) model. In particular, we study the B(E2) inter-band transition strengths between the ground state, γ and, β-bands. The model succesfully describes in a systematic way rotational features in these nuclei and allows to extrapolate toward the midshell nucleus 170Dy.

  14. Single molecule magnet behaviour in a rare trinuclear {Cr(III)Dy} methoxo-bridged complex.

    PubMed

    Car, Pierre-Emmanuel; Favre, Annaïck; Caneschi, Andrea; Sessoli, Roberta

    2015-09-28

    The reaction of the chromium(iii) chloride tetrahydrofuran complex with the dipivaloylmethane ligand, the lanthanide alcoholic salt DyCl3·CH3OH and the 1,1,1-tris(hydroxymethyl)-ethane ligand resulted in the formation of a new trinuclear chromium-dysprosium complex. Magnetic investigations revealed that the new 3d-4f complex exhibits single molecule magnet behaviour. PMID:26282265

  15. Theoretical analysis of experimental data on {sup 160}Dy that were obtained in studying beta decay

    SciTech Connect

    Usmanov, P. N. Adam, I.; Salikhbaev, U. S.; Solnyshkin, A. A.

    2010-12-15

    Nonadiabatic effects manifesting themselves in the energies of excited states and in the probabilities for electric transitions in {sup 160}Dy are studied on the basis of a phenomenological model of the nucleus. The energies of positive-parity low-lying states and the reduced probabilities B(E2) for both intraband and interband transitions between them are calculated. A comparison with experimental data is performed.

  16. Crystal growth of large size Dy3Al5O12 garnet single crystals

    NASA Astrophysics Data System (ADS)

    Kimura, Hideo; Sakamoto, Masaru; Numazawa, Takenori; Sato, Mitsunori; Maeda, Hiroshi

    1990-01-01

    Crystal growth conditions using the Czochralski technique were examined in order to be able to grow large-size disprosium-aluminum-garnet single crystals; these are useful as a working material in a practical magnetic refrigeration system. Using the best conditions, large-size bubble-free Dy3Al5O12 single crystals 50 mm in diameter were grown from a stoichiometric melt composition using a seed of Y3Al5O12 single crystal.

  17. A Comparison of the Performance of the EQ-5D and the EQ-5D-Y Health-Related Quality of Life Instruments in South African Children

    ERIC Educational Resources Information Center

    Jelsma, Jennifer

    2010-01-01

    The aim of this study was to investigate the performance of the recent EQ-5D-Y instrument compared with the standard EQ-5D in assessing the health-related quality of life of high school children in Cape Town. Either the EQ-5D or the EQ-5D-Y was given to high school children. The sample consisted of 521 respondents. The EQ-5D-Y was found to be…

  18. BOREAS Level-0 ER-2 Navigation Data

    NASA Technical Reports Server (NTRS)

    Strub, Richard; Dominguez, Roseanne; Newcomer, Jeffrey A.; Hall, Forrest G. (Editor)

    2000-01-01

    The BOREAS Staff Science effort covered those activities that were BOREAS community-level activities or required uniform data collection procedures across sites and time. These activities included the acquisition, processing, and archiving of aircraft navigation/attitude data to complement the digital image data. The level-0 ER-2 navigation data files contain aircraft attitude and position information acquired during the digital image and photographic data collection missions. Temporally, the data were acquired from April to September 1994. Data were recorded at intervals of 5 seconds. The data are stored in tabular ASCII files.

  19. Modeling the magnetic structure of Dy7Fe3 metallic glass

    NASA Astrophysics Data System (ADS)

    Karlsson, L.; Wannberg, A.; McGreevy, R. L.; Keen, D. A.

    2000-01-01

    Neutron diffraction measurements have been made on amorphous Dy7Fe3 at 13 temperatures between 10 and 300 K. The data have been modeled using the reverse Monte Carlo method under the assumption that the atomic structure is isomorphous with that of Dy7Ni3 [D. A. Keen and R. L. McGreevy, J. Phys. Condens. Matter 2, 7383 (1991)]. From the resulting configurations we find that the near-neighbor ordering is ferromagnetic, but the spin-spin correlation is strongly oscillatory. We also find that there is no strong radial component in the spin-spin correlations; this has previously been shown for Dy7-xYxNi3 glasses [D. A. Keen, R. L. McGreevy, R. I. Bewley, and R. Cywinski, Nucl. Instrum. Methods Phys. Res. A 354, 48 (1995); D. A. Keen, R. I. Bewley, R. Cywinski, and R. L. McGreevy, Phys. Rev. B 54, 1036 (1996)]. By integrating the first peak in the spin-spin correlation function and taking it as a function of temperature, we find a clear point of inflexion at 80 K. This signifies the ordering temperature, in good agreement with susceptibility measurements. Since this curve is derived from the near-neighbor ordering the result shows that the material orders magnetically on all length scales at the same temperature; this is quite distinct from the type of domain ordering observed in, e.g., Fe1-xBx glasses.

  20. Magnetocaloric Effect and Critical Behavior in Fe-Dy-Zr Rapidly Quenched Alloys

    NASA Astrophysics Data System (ADS)

    Dan, Nguyen Huy; Yen, Nguyen Hai; Thanh, Pham Thi

    2016-06-01

    In this paper, we present our study results for Fe90-x Dy x Zr10 (x = 1-6) alloy ribbons with thickness of about 15 µm prepared by using a melt-spinning technique. Structure and magnetic properties of the ribbons were investigated by using x-ray diffraction analysis and magnetization measurements, respectively. The results show that the alloy is almost amorphous with x = 1, but partly crystalline with x ≥ 2, i.e. the glass forming ability (GFA) of the alloy is reduced with an increase of the Dy-concentration. Curie temperature, T C, of the alloy is considerably increased, from 273 K (for x = 1) to 305 K (for x = 3), by increasing the Dy-concentration. Maximum magnetic entropy change, |∆S m|max, of the alloys with x = 1 and 2 was respectively determined to be 0.84 and 0.93 J kg-1 K-1 with magnetic field change ΔH = 12 kOe. High refrigerant capacity (RC > 80 J kg-1) at room temperature region has been obtained for the alloy revealing its possibility for practical application in magnetic refrigeration. Critical analyses around the ferromagnetic-paramagnetic phase transitions, by using the Arrott-Noakes method, indicate long-range ferromagnetic orders in the alloys.

  1. Degradation of hydrogen sulfide by Xanthomonas sp. strain DY44 isolated from peat.

    PubMed Central

    Cho, K S; Hirai, M; Shoda, M

    1992-01-01

    Xanthomonas sp. strain DY44, capable of degrading H2S, was isolated from dimethyl disulfide-acclimated peat. This bacterium removed H2S either as a single gas or in the presence of the sulfur-containing compounds methanethiol, dimethyl sulfide, and dimethyl disulfide. The maximum specific H2S removal rate, obtained in the late stationary phase, was 3.92 mmol g of dry cells-1 h-1 (6.7 x 10(-16) mol cell-1 h-1) at pH 7 and 30 degrees C through a batch experiment in a basal mineral medium. Since Xanthomonas sp. strain DY44 exhibited no autotrophic growth with H2S, the H2S removal was judged not to be a consequence of chemolithotrophic activity. By using X-ray photoelectron spectroscopy, the metabolic product of H2S oxidation was determined to be polysulfide, which has properties very similar to those of elemental sulfur. Autoclaved cells (120 degrees C, 20 min) did not show H2S degradation, but cells killed by gamma-irradiation and cell extracts both oxidized H2S, suggesting the existence of a heat-labile intracellular enzymatic system for H2S oxidation. When Xanthomonas sp. strain DY44 was inoculated into fibrous peat, this strain degraded H2S without lag time, suggesting that it will be a good candidate for maintaining high H2S removability in the treatment of exhaust gases. PMID:1599238

  2. Luminescence and photometric characterization of K+ compensated CaMoO4:Dy3+ nanophosphors.

    PubMed

    Dutta, S; Som, S; Sharma, S K

    2013-07-14

    A series of CaMoO4 phosphors doped with trivalent dysprosium (Dy(3+)) and codoped with potassium (K(+)) ions were prepared by hydrothermal method. The nanostructures of the as-synthesized phosphors were investigated by X-ray diffraction (XRD). The results reveal that the obtained powder phosphors are single-phase scheelite structure with tetragonal symmetry and the crystallite size is in the range of 10-60 nm. The emission spectra show a bright yellow emission at 576 nm and blue emission at 487 nm. As a charge compensator, K(+) ions were incorporated into CaMoO4:Dy(3+) phosphors, which enhance the PL intensities depending on the doping concentration of K(+). The CIE parameters such as colour coordinates, colour correlated temperature and luminous efficacy of radiation were calculated using spectral energy distribution functions and McCamy's empirical formula. Photometric characterization indicates the suitability of K(+) compensated CaMoO4:Dy(3+) phosphor for white LED applications. PMID:23677066

  3. Shedding light on the single-molecule magnet behavior of mononuclear Dy(III) complexes.

    PubMed

    Aravena, Daniel; Ruiz, Eliseo

    2013-12-01

    General requirements for obtaining Dy(III) single-molecule magnets (SMM) were studied by CASSCF+RASSI calculations on both real and model systems. A set of 20 Dy(III) complexes was considered using their X-ray crystal structure for our calculations. Theoretical results were compared with their experimental slow relaxation data, and general conclusions about the calculated key parameters related with SMM behavior are presented. The effect of the coordination geometry and nature of ligands is discussed based on calculations on real and model systems. We found two different patterns to exhibit SMM behavior: the first one leads to the largest axial anisotropy in complexes showing heterolepticity of the ligand environment (more important than symmetric requirements), while the second one corresponds to sandwich-shaped complexes with a smaller anisotropy. Thus, most existing mononuclear zero-field SMMs adopting a heteroleptic coordination mode mixing neutral and anionic ligands present the same pattern in the electrostatic potential induced by their ligands, with a lower potential island related to the presence of neutral ligands inside a high potential background related with anionic groups. The existence of different electrostatic regions caused by the ligands induces a preferential orientation to reduce the electron repulsion for the electron density of the Dy(III) cations, resulting in the magnetic anisotropy. PMID:24237385

  4. Effects of pure and dyed PCE on physical and interfacial properties of remedial solutions.

    PubMed

    Jeong, Seung-Woo; Wood, A Lynn; Lee, Tony R

    2002-11-11

    Hydrophobic dyes have been used to visually distinguish dense non-aqueous phase liquid (DNAPL) contaminants from background aqueous phases and soils. The objective of this study was to evaluate the effects of a dyed DNAPL, 0.5 g Oil-Red-O/l of PCE, on the physical properties of remedial solutions: water, co-solvents (50, 70, and 90% (v/v) ethanol), and surfactants (4% (w) sodium dihexyl sulfosuccinate). This study compared the densities, viscosities, and interfacial tensions (IFTs) of the remedial solutions in contact with both dyed and undyed PCE. The presence of the dye in PCE substantially alters the IFTs of water and ethanol solutions, while there is no apparent difference in IFTs of surfactant solutions. The remedial solutions saturated with PCE showed higher viscosities and densities than pure remedial solutions. Solutions with high ethanol content exhibited the largest increases in liquid density. Because physical properties affect the flow of the remedial solutions in porous media, experiments using dyed DNAPLs should assess the influence of dyes on fluid and interfacial properties prior to remediation process analysis. PMID:12409243

  5. Tuning the Magnetic Interactions and Relaxation Dynamics of Dy2 Single-Molecule Magnets.

    PubMed

    Xue, Shufang; Guo, Yun-Nan; Ungur, Liviu; Tang, Jinkui; Chibotaru, Liviu F

    2015-09-28

    Efficient modulation of single-molecule magnet (SMM) behavior was realized by deliberate structural modification of the Dy2 cores of [Dy2(a'povh)2(OAc)2(DMF)2] (1) and [Zn2Dy2(a'povh)2(OAc)6]⋅4 H2O (2; H2a'povh = N'-[amino(pyrimidin-2-yl)methylene]-o-vanilloyl hydrazine). Compound 1 having fourfold linkage between the two dysprosium ions shows high-performance SMM behavior with a thermal energy barrier of 322.1 K, whereas only slow relaxation is observed for compound 2 with only twofold connection between the dysprosium ions. This remarkable discrepancy is mainly because of strong axiality in 1 due to one pronounced covalent bond, as revealed by experimental and theoretical investigations. The significant antiferromagnetic interaction derived from bis(μ2-O) and two acetate bridging groups was found to be crucial in leading to a nonmagnetic ground state in 1, by suppressing zero-field quantum tunneling of magnetization. PMID:26272604

  6. Molten salt synthesis and luminescent properties of YVO4:Ln (Ln = Eu3+, Dy3+) nanophosphors.

    PubMed

    Liu, Chenglu; Wang, Fang; Jia, Peiyun; Lin, Jun; Zhou, Zhiqiang

    2012-01-01

    Eu3+ and Dy(3+)-doped YVO4 nanocrystallites were successfully prepared at 400 degrees C in equal moles of NaNO3 and KNO3 molten salts. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, transmission electronic microscopy (TEM), photoluminescence (PL) spectrum and lifetime were used to characterize the nanocrystallites. XRD results demonstrate that NaOH concentration and annealing temperature play important roles in phase purity and crystallinity of the nanocrystallites, the optimum NaOH concentration and annealing temperature being 6:40 and 400 degrees C respectively. TEM micrographs show the nanocrystallites are well crystallized with a cubic morphology in an average grain size of about 18 nm. Upon excitation of the vanadate group at 314 nm, YVO4:Eu3+ and YVO4:Dy3+ nanocrystallites exhibit the characteristic emission of Eu3+ and Dy3+, which indicates that there is an energy transfer from the vanadate group to the rare earth ions. Moreover, the structure and luminescent properties of the nanocrystallites were compared with their bulk counterparts with same composition in detail. PMID:22523959

  7. Physical and optical properties of magnesium sulfoborate glasses doped Dy3+ ions

    NASA Astrophysics Data System (ADS)

    Dalhatu, S. A.; Deraman, Karim; Hussin, R.

    2016-04-01

    The optical properties of alkaline earth borate glasses doped with rare earth are attractive field of research due to many optical applications. We have concentrated on the physical and optical properties of MgO-SO4-B2O3 glass with different concentrations of Dy3+ ions. The samples of glass were prepared using the melting quenching technique. The physical parameter and optical properties of the prepared glass were determined. It was observed that the density of the glass samples increased and the molar volume reduced with respect to Dy3+ ions content. Dy3+: MgO-SO4-B2O3 glass displayed 10 absorption bands with hypersensitive transition around 1265 nm (6H15/6 →6F11/2). Two intense luminescence emissions were observed at 482 nm (4F9/2 →6H15/2: blue) and 573 nm (4F9/2 →6H13/2: yellow) and weak band at 662 nm (4F9/2 →6H11/2: red) with excitation wavelength 380 nm. A strong enhancement in the emission peaks at 573 nm in the yellow region was observed with the 0.07 mol% concentration of dysprosium oxide, which may assign to the energy transfer from Mg2+ to Mg3+ ions. Beyond the optimum concentration, contrary result was observed.

  8. Supercooled spin liquid state in the frustrated pyrochlore Dy2Ti2O7

    PubMed Central

    Kassner, Ethan R.; Eyvazov, Azar B.; Pichler, Benjamin; Munsie, Timothy J. S.; Dabkowska, Hanna A.; Luke, Graeme M.; Davis, J. C. Séamus

    2015-01-01

    A “supercooled” liquid develops when a fluid does not crystallize upon cooling below its ordering temperature. Instead, the microscopic relaxation times diverge so rapidly that, upon further cooling, equilibration eventually becomes impossible and glass formation occurs. Classic supercooled liquids exhibit specific identifiers including microscopic relaxation times diverging on a Vogel–Tammann–Fulcher (VTF) trajectory, a Havriliak–Negami (HN) form for the dielectric function ε(ω,T), and a general Kohlrausch–Williams–Watts (KWW) form for time-domain relaxation. Recently, the pyrochlore Dy2Ti2O7 has become of interest because its frustrated magnetic interactions may, in theory, lead to highly exotic magnetic fluids. However, its true magnetic state at low temperatures has proven very difficult to identify unambiguously. Here, we introduce high-precision, boundary-free magnetization transport techniques based upon toroidal geometries and gain an improved understanding of the time- and frequency-dependent magnetization dynamics of Dy2Ti2O7. We demonstrate a virtually universal HN form for the magnetic susceptibility χ(ω,T), a general KWW form for the real-time magnetic relaxation, and a divergence of the microscopic magnetic relaxation rates with the VTF trajectory. Low-temperature Dy2Ti2O7 therefore exhibits the characteristics of a supercooled magnetic liquid. One implication is that this translationally invariant lattice of strongly correlated spins may be evolving toward an unprecedented magnetic glass state, perhaps due to many-body localization of spin. PMID:26130810

  9. DyCoH: an innovative tool to dynamic contrast enhancement analysis.

    PubMed

    Russo, Valentina; Setola, Roberto; Del Vescovo, Riccardo; Grasso, Rosario Francesco; Zobel, Bruno Beomonte

    2007-01-01

    Contrast-Enhancement (CE) is an innovative approach, used in radiological framework, to evaluate the vascularization of the diseases. This non-invasive method determines the nature of a diseases, analysing the perfusion' dynamic of contrast media in the tissues. In this paper we present an innovative tool named DyCoH (Dynamic Contrast Enhancement). This software, being specifically designed for this type of analysis, provides to medical doctor, in a very user-friendly framework, all the information needed to perform the CE analysis. DyCoH produces four inspectionable colour-maps that radiologists can use to identify the most relevant areas over which dynamically evaluates the contrast enhancement curve. However, the most interesting feature of DyCoH is its capability to manage, into a single framework, DICOM images produced by US, CT and MR of different vendors, allowing to support many types of clinical tests and to compare results provided by different diagnostic devices. Clinical tests have shown the effectiveness of the software and its capability to concretely support CE diagnoses. PMID:18001889

  10. Magnetic and magneto-optical properties of (Tb,Dy)Nd/FeCo multilayers (abstract)

    NASA Astrophysics Data System (ADS)

    Yu, X. Y.; Fujiwara, Y.; Watabe, H.; Iwata, S.; Tsunashima, S.; Uchiyama, S.

    1994-05-01

    Nd-Co and Nd-FeCo amorphous films are known to have larger Kerr rotation θk at shorter wavelength and ultraviolet light compared with other RE-TM (rare earth-transition) amorphous films. This property is desirable for MO (magneto-optical) media for the next generation. In order to satisfy the perpendicular magnetization condition, we replaced a part of Nd by Gd to decrease the saturation magnetization Ms and applied the multilayer (ML) structure to enhance the perpendicular anisotropy Ku. Then we succeeded in getting a new ML medium of Nd0.34Gd0.66/Fe0.9Co0.1 with a bilayer period of 1 nm. However, the substitution of 66% Gd resulted in undesirable decreases of Kerr rotation and coercivity. In this experiment, a part of Nd is replaced by either Tb or Dy instead of Gd with an expectation that the amount of replacement to get the perpendicular magnetization configuration may be smaller since Tb and Dy have large one ion anisotropy compared with Gd. The magnetic and MO properties of Nd(Tb,Dy)/FeCo MLs will be reported. In the case of Tb, for example, a square Kerr hysteresis loop is obtained by the substitution of about 40%. However, θK at 400 nm is about 0.30°, which is larger than that of Tb-FeCo but smaller than NdGd/FeCo MLs.

  11. Effect of Dy-substitution on the structural, vibrational, and multiferroic properties of BiFeO{sub 3} nanoparticles

    SciTech Connect

    Muneeswaran, M.; Giridharan, N. V.

    2014-06-07

    Dysprosium (Dy) modified BiFeO{sub 3} [Bi{sub 1−x}Dy{sub x}FeO{sub 3} (x = 0.05, 0.10, and 0.15)] nanoparticles have been synthesized by a low temperature co-precipitation method. Rietveld analysis of X-ray diffraction data reveals a transformation from rhombohedral structure to orthorhombic structure with increase in the Dy concentration. From the transmission electron microscopy analysis, it is observed that the particle sizes of Bi{sub 1−x}Dy{sub x}FeO{sub 3} (x = 0.05, 0.10, and 0.15) nanoparticles range between 50–70, 40–50, and 30–50 nm, respectively. Raman spectra of Bi{sub 1−x}Dy{sub x}FeO{sub 3} (x = 0.05) belonging to rhombohedral (R3c) structure show 4A{sub 1} and 7E fundamental Raman modes in the range of 100–650 cm{sup −1} and two-phonon scattering modes such as 2A{sub 4} (longitudinal optical), 2E8 (transverse optical (TO)), and 2E{sub 9} (TO) in the range of 950–1270 cm{sup −1}. Suppression, broadening, and shifting of Raman modes have been observed with further increase in Dy concentration. The fundamental Raman modes of Bi{sub 1−x}Dy{sub x}FeO{sub 3} (x = 0.15) are assigned under orthorhombic (pnma) rather than rhombohedral (R3c) as the Rietveld analysis of X-ray diffraction data predicts a structural transformation for this particular composition. A complete suppression of two phonon modes has been noticed for this composition. An anomaly in the temperature dependent dielectric studies has been observed in all the samples at the vicinity of Neel temperature indicating a magnetic ordering, and an increase in magnetization with increase of Dy concentration in BiFeO{sub 3} is noticed from the room temperature magnetic studies. P–E hysteresis loop studies show a decrease of remnant polarization (P{sub r}) with the increase in Dy concentration and disappearance of hysteresis loop occurs for Bi{sub 1−x}Dy{sub x}FeO{sub 3} (x = 0.15) depicting a transformation from non-centrosymmetric (R3c) to

  12. CD90-positive cells, an additional cell population, produce laminin {alpha}2 upon transplantation to dy{sup 3k}/dy{sup 3k} mice

    SciTech Connect

    Fukada, So-ichiro Yamamoto, Yukiko; Segawa, Masashi; Sakamoto, Kenta; Nakajima, Mari; Sato, Masaki; Morikawa, Daisuke; Uezumi, Akiyoshi; Miyagoe-Suzuki, Yuko; Takeda, Shin'ichi; Tsujikawa, Kazutake; Yamamoto, Hiroshi

    2008-01-01

    Laminin {alpha}2 is a component of skeletal and cardiac muscle basal lamina. A defect of the laminin {alpha}2 chain leads to severe congenital muscular dystrophy (MDC1A) in humans and dy/dy mice. Myogenic cells including myoblasts, myotubes, and myofibers in skeletal muscle are a possible source of the laminin {alpha}2 chain, and myogenic cells are thus proposed as a cell source for congenital muscular dystrophy therapy. However, we observed production of laminin {alpha}2 in non-myogenic cells of normal mice, and we could enrich these laminin {alpha}2-producing cells in CD90{sup +} cell fractions. Intriguingly, the number of CD90{sup +} cells increased dramatically during skeletal muscle regeneration in mice. This fraction did not include myogenic cells but exhibited a fibroblast-like phenotype. Moreover, these cells were resident in skeletal muscle, not derived from bone marrow. Finally, the production of laminin {alpha}2 in CD90{sup +} cells was not dependent on fusion with myogenic cells. Thus, CD90{sup +} cells are a newly identified additional cell fraction that increased during skeletal muscle regeneration in vivo and could be another cell source for therapy for lama2-deficient muscular dystrophy.

  13. Dysfunction of Wntless triggers the retrograde Golgi-to-ER transport of Wingless and induces ER stress

    PubMed Central

    Zhang, Peng; Zhou, Lujun; Pei, Chunli; Lin, Xinhua; Yuan, Zengqiang

    2016-01-01

    Secreted Wnts play diverse roles in a non-cell-autonomous fashion. However, the cell-autonomous effect of unsecreted Wnts remains unknown. Endoplasmic reticulum (ER) stress is observed in specialized secretory cells and participates in pathophysiological processes. The correlation between Wnt secretion and ER stress remains poorly understood. Here, we demonstrated that Drosophila miR-307a initiates ER stress specifically in wingless (wg)-expressing cells through targeting wntless (wls/evi). This phenotype could be mimicked by retromer loss-of-function or porcupine (porc) depletion, and rescued by wg knockdown, arguing that unsecreted Wg triggers ER stress. Consistently, we found that disrupting the secretion of human Wnt5a also induced ER stress in mammalian cells. Furthermore, we showed that a C-terminal KKVY-motif of Wg is required for its retrograde Golgi-to-ER transport, thus inducing ER stress. Next, we investigated if COPI, the regulator of retrograde transport, is responsible for unsecreted Wg to induce ER stress. To our surprise, we found that COPI acts as a novel regulator of Wg secretion. Taken together, this study reveals a previously unknown Golgi-to-ER retrograde route of Wg, and elucidates a correlation between Wnt secretion and ER stress during development. PMID:26887613

  14. TFG Promotes Organization of Transitional ER and Efficient Collagen Secretion.

    PubMed

    McCaughey, Janine; Miller, Victoria J; Stevenson, Nicola L; Brown, Anna K; Budnik, Annika; Heesom, Kate J; Alibhai, Dominic; Stephens, David J

    2016-05-24

    Collagen is the most abundant protein in the animal kingdom. It is of fundamental importance during development for cell differentiation and tissue morphogenesis as well as in pathological processes such as fibrosis and cancer cell migration. However, our understanding of the mechanisms of procollagen secretion remains limited. Here, we show that TFG organizes transitional ER (tER) and ER exit sites (ERESs) into larger structures. Depletion of TFG results in dispersion of tER elements that remain associated with individual ER-Golgi intermediate compartments (ERGICs) as largely functional ERESs. We show that TFG is not required for the transport and packaging of small soluble cargoes but is necessary for the export of procollagen from the ER. Our work therefore suggests a key relationship between the structure and function of ERESs and a central role for TFG in optimizing COPII assembly for procollagen export. PMID:27184855

  15. Fluvoxamine alleviates ER stress via induction of Sigma-1 receptor.

    PubMed

    Omi, T; Tanimukai, H; Kanayama, D; Sakagami, Y; Tagami, S; Okochi, M; Morihara, T; Sato, M; Yanagida, K; Kitasyoji, A; Hara, H; Imaizumi, K; Maurice, T; Chevallier, N; Marchal, S; Takeda, M; Kudo, T

    2014-01-01

    We recently demonstrated that endoplasmic reticulum (ER) stress induces sigma-1 receptor (Sig-1R) expression through the PERK pathway, which is one of the cell's responses to ER stress. In addition, it has been demonstrated that induction of Sig-1R can repress cell death signaling. Fluvoxamine (Flv) is a selective serotonin reuptake inhibitor (SSRI) with a high affinity for Sig-1R. In the present study, we show that treatment of neuroblastoma cells with Flv induces Sig-1R expression by increasing ATF4 translation directly, through its own activation, without involvement of the PERK pathway. The Flv-mediated induction of Sig-1R prevents neuronal cell death resulting from ER stress. Moreover, Flv-induced ER stress resistance reduces the infarct area in mice after focal cerebral ischemia. Thus, Flv, which is used frequently in clinical practice, can alleviate ER stress. This suggests that Flv could be a feasible therapy for cerebral diseases caused by ER stress. PMID:25032855

  16. Changes of Tb Emission by Non-radiative Energy Transfer from Dy in Gd2O2S:Tb Phosphor

    NASA Astrophysics Data System (ADS)

    Saraee, Kh. Rezaee Ebrahim; Zadeh, M. Darvish; Mostajaboddavati, M.; Kharieky, A. Aghay

    2016-06-01

    In this study, the Gd2O2S:Tb1.5Dy x=0.3,0.6,0.9 nanophosphor were synthesized by the homogenous precipitation method followed with a sulfur reaction. The fluorescence of Gd2O2S:Tb1.5,Dy nanophosphors, and the energy transfer between dysprosium (Dy) and Tb have been studied. Although, the two weak emissions of Dy were observed, the terbium (Tb) emission was increased due to energy transfer from Dy ions to Tb ions. The results illustrated that the co-activator of Dy had a significant influence on the spectral properties of the Gd2O2S:Tb1.5 nanophosphor with an optimal amount of Dy (0.3 mol%). Moreover, Gd2O2S:Tb1.5 and Gd2O2S:Tb1.5,Dy nanophosphors screens were prepared with 10 mg/cm2 coating thickness. The scintillation properties of these screens have been investigated. We found a Gd2O2S:Tb1.5,Dy0.3 scintillator can be employed in x-ray imaging applications.

  17. Anisotropic superconducting and normal state magnetic properties of single crystals of RNi*2*B*2*C compounds (R = Y, Gd, Dy, Ho, Er, and Tm)

    SciTech Connect

    Cho, B.

    1995-11-01

    The interaction of superconductivity with magnetism has been one of the most interesting and important phenomena in solid state physics since the 1950`s when small amounts of magnetic impurities were incorporated in superconductors. The discovery of the magnetic superconductors RNi{sub 2}B{sub 2}C (R = rare earth, Y) offers a new system to study this interaction. The wide ranges of superconducting transition (T{sub c}) and antiferromagnetic (AF) ordering temperatures (T{sub N}) (0 K {le} T{sub c} {le} 16 K, 0 K {le} T{sub N} {le} 20 K) give a good opportunity to observe a variety of interesting phenomena. Single crystals of high quality with appropriate size and mass are crucial in examining the anisotropic intrinsic properties. Single crystals have been grown successfully by an unusual high temperature flux method and characterized thoroughly by X-ray, electrical transport, magnetization, neutron scattering, scanning electron microscopy, and other measurements.

  18. ESR study of AuEr dilute alloys

    NASA Astrophysics Data System (ADS)

    Dokter, H. D.; Davidov, D.; Hoekstra, F. R.; Nieuwenhuys, G. J.

    1981-06-01

    ESR linewidth and signal intensity measurements of AuEr (0.2%, 1%, 3%) dilute alloys have been carried out as a function of temperature in order to resolve previous discrepancies regarding the crystal field splitting. The data analysis indicates a splitting of (16 ± 4) K between the Γ 7 ground state and the Γ (1)8 first excited state. No evidence for an additional broadening mechanism associated with Er-Er exchange interactions was observed.

  19. Validation of ERS-1 environmental data products

    NASA Technical Reports Server (NTRS)

    Goodberlet, Mark A.; Swift, Calvin T.; Wilkerson, John C.

    1994-01-01

    Evaluation of the launch-version algorithms used by the European Space Agency (ESA) to derive wind field and ocean wave estimates from measurements of sensors aboard the European Remote Sensing satellite, ERS-1, has been accomplished through comparison of the derived parameters with coincident measurements made by 24 open ocean buoys maintained by the National Oceanic and Atmospheric Administration). During the period from November 1, 1991 through February 28, 1992, data bases with 577 and 485 pairs of coincident sensor/buoy wind and wave measurements were collected for the Active Microwave Instrument (AMI) and Radar Altimeter (RA) respectively. Based on these data, algorithm retrieval accuracy is estimated to be plus or minus 4 m/s for AMI wind speed, plus or minus 3 m/s for RA wind speed and plus or minus 0.6 m for RA wave height. After removing 180 degree ambiguity errors, the AMI wind direction retrieval accuracy was estimated at plus or minus 28 degrees. All of the ERS-1 wind and wave retrievals are relatively unbiased. These results should be viewed as interim since improved algorithms are under development. As final versions are implemented, additional assessments should be conducted to complete the validation.

  20. Radiation Hydrodynamics with FLOW-ER

    NASA Astrophysics Data System (ADS)

    Marcello, Dominic; Tohline, J. E.; Motl, P. M.

    2008-03-01

    The effects of radiative transport are an important aspect of many astrophysical fluid problems, such as binary star accretion discs and common envelope evolution. Unfortunately, the full radiative transport problem is seven dimensional and outside the realm of current computational capabilities. The gray field flux limited diffusion (FLD) approximation has been shown to provide a feasible four dimensional approximation to the full radiative transport problems in many cases. The flux is approximated through an algebraic expression which interpolates between the two extremes of diffusive and free streaming radiation. FLD allows for the exchange of energy and momentum between the fluid and radiation field. We are implementing this into our current Newtonian astrophysical fluid simulation code named FLOW-ER. Unlike other FLD codes, FLOW-ER handles shocks without the use of artificial viscosity. At this point, the code runs in 1D and 2D on a single processor. The ultimate goal is a fully 3D parallel code running on an adaptive mesh. Presented are results for test cases in 1D and 2D, compared to analytic results where available, and to ZeusMP2 when not. This research has been supported, in part, by NSF grants AST-0407070 and AST-0708551.

  1. June 1997 ER-2 Flight Measurements

    NASA Technical Reports Server (NTRS)

    Jones, Irby W.

    2003-01-01

    Within our current understanding of the atmospheric ionizing radiation, the ER-2 flight package was designed to provide a complete characterization of the physical fields and evaluate various dosimetric techniques for routine monitoring. A flight plan was developed to sample the full dynamic range of the atmospheric environment especially at altitudes relevant to the development of the High Speed Civil Transport. The flight of the instruments occurred in June of 1997 where predictive models indicated a maximum in the high altitude radiation environment occurring approximately nine months after the minimum in the solar sunspot cycle. The flights originated at Moffett field at the Ames Research Center on ER-2 aircraft designated as 706. The equipment was shipped mid- May 1997 for unpacking and checkout, size fitting, systems functional test, and preflight testing on aircraft power with flight readiness achieved on May 30, 1997. The equipment was qualified on its first engineering flight on June 2, 1997 and the subsequent science gathering flights followed during the period of June 5-15, 1997. Herein we give an account of the flight operations.

  2. ER Import Sites and Their Relationship to ER Exit Sites: A New Model for Bidirectional ER-Golgi Transport in Higher Plants.

    PubMed

    Lerich, Alexander; Hillmer, Stefan; Langhans, Markus; Scheuring, David; van Bentum, Paulien; Robinson, David G

    2012-01-01

    Per definition, ER exit sites are COPII vesiculation events at the surface of the ER and in higher plants are only visualizable in the electron microscope through cryofixation techniques. Fluorescent COPII labeling moves with Golgi stacks and locates to the interface between the ER and the Golgi. In contrast, the domain of the ER where retrograde COPI vesicles fuse, i.e., ER import sites (ERIS), has remained unclear. To identify ERIS we have employed ER-located SNAREs and tethering factors. We screened several SNAREs (SYP81, the SYP7 family, and USE1) to find a SNARE whose overexpression did not disrupt ER-Golgi traffic and which gave rise to discrete fluorescent punctae when expressed with an XFP tag. Only the Qc-SNARE SYP72 fulfilled these criteria. When coexpressed with SYP72-YFP, both the type I-membrane protein RFP-p24δ5 and the luminal marker CFP-HDEL whose ER localization are due to an efficient COPI-mediated recycling, form nodules along the tubular ER network. SYP72-YFP colocalizes with these nodules which are not seen when RFP-p24δ5 or CFP-HDEL is expressed alone or when SYP72-YFP is coexpressed with a mutant form of RFP-p24δ5 that cannot exit the ER. SYP72-YFP does not colocalize with Golgi markers, except when the Golgi stacks are immobilized through actin depolymerization. Endogenous SYP7 SNAREs, also colocalize with immobilized COPII/Golgi. In contrast, XFP-tagged versions of plant homologs to TIP20 of the Dsl1 COPI-tethering factor complex, and the COPII-tethering factor p115 colocalize perfectly with Golgi stacks irrespective of the motile status. These data suggest that COPI vesicle fusion with the ER is restricted to periods when Golgi stacks are stationary, but that when moving both COPII and COPI vesicles are tethered and collect in the ER-Golgi interface. Thus, the Golgi stack and an associated domain of the ER thereby constitute a mobile secretory and recycling unit: a unique feature in eukaryotic cells. PMID:22876251

  3. Ire1 supports normal ER differentiation in developing Drosophila photoreceptors

    PubMed Central

    Xu, Zuyuan; Chikka, Madhusudana Rao; Xia, Hongai; Ready, Donald F.

    2016-01-01

    ABSTRACT The endoplasmic reticulum (ER) serves virtually all aspects of cell physiology and, by pathways that are incompletely understood, is dynamically remodeled to meet changing cell needs. Inositol-requiring enzyme 1 (Ire1), a conserved core protein of the unfolded protein response (UPR), participates in ER remodeling and is particularly required during the differentiation of cells devoted to intense secretory activity, so-called ‘professional’ secretory cells. Here, we characterize the role of Ire1 in ER differentiation in the developing Drosophila compound eye photoreceptors (R cells). As part of normal development, R cells take a turn as professional secretory cells with a massive secretory effort that builds the photosensitive membrane organelle, the rhabdomere. We find rough ER sheets proliferate as rhabdomere biogenesis culminates, and Ire1 is required for normal ER differentiation. Ire1 is active early in R cell development and is required in anticipation of peak biosynthesis. Without Ire1, the amount of rough ER sheets is strongly reduced and the extensive cortical ER network at the rhabdomere base, the subrhabdomere cisterna (SRC), fails. Instead, ER proliferates in persistent and ribosome-poor tubular tangles. A phase of Ire1 activity early in R cell development thus shapes dynamic ER. PMID:26787744

  4. Enhancement of thermopower of TAGS-85 high-performance thermoelectric materials by doping with the rare earth Dy

    SciTech Connect

    Levin, Evgenii; Budko, Serfuei; Schmidt-Rohr, Klaus

    2012-04-10

    Enhancement of thermopower is achieved by doping the narrow-band semiconductor Ag{sub 6.52}Sb{sub 6.52}Ge{sub 36.96}Te{sub 50} (acronym TAGS-85), one of the best p-type thermoelectric materials, with 1 or 2% of the rare earth dysprosium (Dy). Evidence for the incorporation of Dy into the lattice is provided by X-ray diffraction and increased orientation-dependent local fields detected by {sup 125}Te NMR spectroscopy. Since Dy has a stable electronic configuration, the enhancement cannot be attributed to 4f-electron states formed near the Fermi level. It is likely that the enhancement is due to a small reduction in the carrier concentration, detected by {sup 125}Te NMR spectroscopy, but mostly due to energy filtering of the carriers by potential barriers formed in the lattice by Dy, which has large both atomic size and localized magnetic moment. The interplay between the thermopower, the electrical resistivity, and the thermal conductivity of TAGS-85 doped with Dy results in an enhancement of the power factor (PF) and the thermoelectric figure of merit (ZT) at 730 K, from PF = 28 μW cm{sup −1} K{sup −2} and ZT ≤ 1.3 in TAGS-85 to PF = 35 μW cm{sup −1} K{sup −2} and ZT ≥ 1.5 in TAGS-85 doped with 1 or 2% Dy for Ge. This makes TAGS-85 doped with Dy a promising material for thermoelectric power generation.

  5. ER trapping reveals Golgi enzymes continually revisit the ER through a recycling pathway that controls Golgi organization

    PubMed Central

    Sengupta, Prabuddha; Satpute-Krishnan, Prasanna; Seo, Arnold Y.; Burnette, Dylan T.; Patterson, George H.; Lippincott-Schwartz, Jennifer

    2015-01-01

    Whether Golgi enzymes remain localized within the Golgi or constitutively cycle through the endoplasmic reticulum (ER) is unclear, yet is important for understanding Golgi dependence on the ER. Here, we demonstrate that the previously reported inefficient ER trapping of Golgi enzymes in a rapamycin-based assay results from an artifact involving an endogenous ER-localized 13-kD FK506 binding protein (FKBP13) competing with the FKBP12-tagged Golgi enzyme for binding to an FKBP-rapamycin binding domain (FRB)-tagged ER trap. When we express an FKBP12-tagged ER trap and FRB-tagged Golgi enzymes, conditions precluding such competition, the Golgi enzymes completely redistribute to the ER upon rapamycin treatment. A photoactivatable FRB-Golgi enzyme, highlighted only in the Golgi, likewise redistributes to the ER. These data establish Golgi enzymes constitutively cycle through the ER. Using our trapping scheme, we identify roles of rab6a and calcium-independent phospholipase A2 (iPLA2) in Golgi enzyme recycling, and show that retrograde transport of Golgi membrane underlies Golgi dispersal during microtubule depolymerization and mitosis. PMID:26598700

  6. Orthorhombic superstructures within the rare earth strontium-doped cobaltate perovskites: Ln1-xSr xCoO 3-δ ( Ln=Y 3+, Dy 3+-Yb 3+; 0.750⩽ x⩽0.875)

    NASA Astrophysics Data System (ADS)

    James, Michael; Avdeev, Maxim; Barnes, Paris; Morales, Liliana; Wallwork, Kia; Withers, Ray

    2007-08-01

    A combination of electron, synchrotron X-ray and neutron powder diffraction reveals a new orthorhombic structure type within the Sr-doped rare earth perovskite cobaltates Ln1-xSr xCoO 3-δ ( Ln=Y 3+, Dy 3+, Ho 3+, Er 3+, Tm 3+and Yb 3+). Electron diffraction shows a C-centred cell based on a 2√2 ap×4 ap×4√2 ap superstructure of the basic perovskite unit. Not all of these very weak satellite reflections are evident in the synchrotron X-ray and neutron powder diffraction data and the average structure of each member of this series could only be refined based on Cmma symmetry and a 2√2 ap×4 ap×2√2 ap cell. The nature of structural and magnetic ordering in these phases relies on both oxygen vacancy and cation distribution. A small range of solid solution exists where this orthorhombic structure type is observed, centred roughly around the compositions Ln0.2Sr 0.8CoO 3-δ. In the case of Yb 3+ the pure orthorhombic phase was only observed for 0.850⩽ x⩽0.875. Tetragonal ( I4 /mmm; 2 ap×2 ap×4 ap) superstructures were observed for compositions having higher or lower Sr-doping levels, or for compounds with rare earth ions larger than Dy 3+. These orthorhombic phases show mixed valence (3+/4+) cobalt oxidation states between 3.2+ and 3.3+. DC magnetic susceptibility measurements show an additional magnetic transition for these orthorhombic phases compared to the associated tetragonal compounds with critical temperatures > 330 K.

  7. Untangling the web: Mechanisms underlying ER network formation

    PubMed Central

    Goyal, Uma; Blackstone, Craig

    2013-01-01

    The ER is a continuous membrane system consisting of the nuclear envelope, flat sheets often studded with ribosomes, and a polygonal network of highly-curved tubules extending throughout the cell. Although protein and lipid biosynthesis, protein modification, vesicular transport, Ca2+dynamics, and protein quality control have been investigated in great detail, mechanisms that generate the distinctive architecture of the ER have been uncovered only recently. Several protein families including the reticulons and REEPs/DP1/Yop1p harbor hydrophobic hairpin domains that shape high-curvature ER tubules and mediate intramembrane protein interactions. Members of the atlastin/RHD3/Sey1p family of dynamin-related GTPases interact with the ER-shaping proteins and mediate the formation of three-way junctions responsible for the polygonal structure of the tubular ER network, with Lunapark proteins acting antagonistically. Additional classes of tubular ER proteins including some REEPs and the M1 spastin ATPase interact with the microtubule cytoskeleton. Flat ER sheets possess a different complement of proteins such as p180, CLIMP-63 and kinectin implicated in shaping, cisternal stacking and cytoskeletal interactions. The ER is also in constant motion, and numerous signaling pathways as well as interactions among cytoskeletal elements, the plasma membrane, and organelles cooperate to position and shape the ER dynamically. Finally, many proteins involved in shaping the ER network are mutated in the most common forms of hereditary spastic paraplegia, indicating a particular importance for proper ER morphology and distribution in large, highly-polarized cells such as neurons. PMID:23602970

  8. Spectroscopy of the Er-doped lithium tetraborate glasses

    NASA Astrophysics Data System (ADS)

    Padlyak, B. V.; Lisiecki, R.; Ryba-Romanowski, W.

    2016-04-01

    The electron paramagnetic resonance (EPR), optical absorption, and luminescence (emission and excitation) spectra as well as luminescence kinetics of the Er-doped glasses with Li2B4O7 composition were investigated and analysed. The high optical quality glasses with Li2B4O7:Er composition containing 0.5 and 1.0 mol.% Er2O3 were obtained from corresponding polycrystalline compound by standard glass synthesis. The EPR spectroscopy in the 4.2-300 K temperature range and optical spectroscopy at 300 K show that the Er impurity is incorporated into the network of Li2B4O7 glass as Er3+ (4f11, 4I15/2) ions, exclusively. The local structure of the Er3+ luminescence centres in Li sites of the glass network is proposed. Based on the standard Judd-Ofelt theory the oscillator strength (Pcal) and experimental oscillator strength (Pexp) for observed absorption transitions as well as phenomenological intensity parameters (Ω2, Ω4, Ω6) for Er3+ centres in the Li2B4O7:Er glass containing 1.0 mol.% Er2O3 were calculated. Spectroscopic parameters of relevance for laser applications, including emission probabilities of transitions (Wr), branching ratios (β), and radiative lifetime (τrad) have been calculated for main observed emission transitions of the Er3+ centres in Li2B4O7:Er glasses. Experimental and calculated lifetimes were compared and quantum efficiency (η) for green (4S3/2 → 4I15/2 transition) and infrared (4I13/2 → 4I15/2 transition) emission bands has been estimated.

  9. Synthesis and photoluminescence characteristics of Dy{sup 3+} doped NaY(WO{sub 4}){sub 2} phosphors

    SciTech Connect

    Liu, Xiaohua; Xiang, Wendou; Chen, Fengming; Hu, Zhengfa; Zhang, Wei

    2013-02-15

    Graphical abstract: The phosphor powders of NaY(WO{sub 4}){sub 2}: Dy{sup 3+} were prepared by solid state reaction. For the different kinds of excitations, the dependence of luminescence intensity on the Tb{sup 3+} concentration was investigated. Display Omitted Highlights: ► We synthesize NaY(WO{sub 4}){sub 2}:Dy{sup 3+} phosphors by the solid-state reaction technique. ► We observe and explain the change of Y/B ratio with Dy{sup 3+} content. ► The I−x curve shows different behavior for different excitations. ► The concentration quenching mechanism is the d–d interaction. -- Abstract: The novel phosphor powders of NaY(WO{sub 4}){sub 2} doped with Dy{sup 3+} were synthesized by solid state reaction. X-ray diffraction analysis showed that the phosphors sintered at 900 °C for 6 h were a pure NaY(WO{sub 4}){sub 2} phase for all the Dy{sup 3+} doping concentrations. The room temperature excitation spectra of the phosphors vary with the Dy{sup 3+} concentration and consist of an intense charge transfer band of WO{sub 4}{sup 2−} groups and weak f–f transition absorption peaks of Dy{sup 3+}. The photoluminescence spectra, excited at the peak wavelength of charge transfer band, exhibit three bands centered at 488, 575 and 662 nm, which originate from the transitions of {sup 4}F{sub 9/2} → {sup 6}H{sub 15/2} (blue), {sup 4}F{sub 9/2} → {sup 6}H{sub 13/2} (yellow) and {sup 4}F{sub 9/2} → {sup 6}H{sub 11/2} (red) of Dy{sup 3+}, respectively. The effects of Dy{sup 3+} concentration on luminescence intensity and the yellow-to-blue intensity ratio of the phosphors were investigated. The different behaviors for the doping concentration dependence of luminescence intensity resulted from the different kinds of excitation was discussed.

  10. THE VERY YOUNG TYPE Ia SUPERNOVA 2013dy: DISCOVERY, AND STRONG CARBON ABSORPTION IN EARLY-TIME SPECTRA

    SciTech Connect

    Zheng, WeiKang; Filippenko, Alexei V.; Nugent, Peter E.; Graham, Melissa; Kelly, Patrick L.; Fox, Ori D.; Shivvers, Isaac; Clubb, Kelsey I.; Li, Weidong; Silverman, Jeffrey M.; Howie Marion, G.; Kasen, Daniel; Wang, Xiaofeng; Valenti, Stefano; Howell, D. Andrew; Ciabattari, Fabrizio; Cenko, S. Bradley; Balam, Dave; Hsiao, Eric; Sand, David; and others

    2013-11-20

    The Type Ia supernova (SN Ia) 2013dy in NGC 7250 (d ≈ 13.7 Mpc) was discovered by the Lick Observatory Supernova Search. Combined with a prediscovery detection by the Italian Supernova Search Project, we are able to constrain the first-light time of SN 2013dy to be only 0.10 ± 0.05 days (2.4 ± 1.2 hr) before the first detection. This makes SN 2013dy the earliest known detection of an SN Ia. We infer an upper limit on the radius of the progenitor star of R {sub 0} ≲ 0.25 R {sub ☉}, consistent with that of a white dwarf. The light curve exhibits a broken power law with exponents of 0.88 and then 1.80. A spectrum taken 1.63 days after first light reveals a C II absorption line comparable in strength to Si II. This is the strongest C II feature ever detected in a normal SN Ia, suggesting that the progenitor star had significant unburned material. The C II line in SN 2013dy weakens rapidly and is undetected in a spectrum 7 days later, indicating that C II is detectable for only a very short time in some SNe Ia. SN 2013dy reached a B-band maximum of M{sub B} = –18.72 ± 0.03 mag ∼17.7 days after first light.

  11. White light emission from Dy3+-doped LiLuF4 single crystal grown by Bridgman method

    NASA Astrophysics Data System (ADS)

    Dong, Yan-ming; Xia, Hai-ping; Fu, Li; Li, Shan-shan; Gu, Xue-mei; Zhang, Jian-li; Wang, Dong-jie; Zhang, Yue-pin; Jiang, Hao-chuan; Chen, Bao-jiu

    2014-07-01

    Lithium lutetium fluoride (LiLuF4) single crystals doped with different Dy3+ ion concentrations were grown by Bridgman method. The Judd-Ofelt (J-O) strength parameters ( Ω 2, Ω 4, Ω 6) of Dy3+ in LiLuF4 crystal are calculated according to the measured absorption spectra and the J-O theory, by which the asymmetry of the Dy3+:LiLuF4 single crystal and the possibility of attaining stimulated emission from 4F9/2 level are analyzed. The capability of the Dy3+:LiLuF4 crystal in generating white light by simultaneous blue and yellow emissions under excitation with ultraviolet light is produced. The effects of excitation wavelength and doping concentration on chromaticity coordinates and photoluminescence intensity are also investigated. Favorable CIE coordinates, x=0.319 3 and y=0.349 3, can be obtained for Dy3+ ion in 2.701% molar doping concentration under excitation of 350 nm.

  12. Ab initio, theoretical and Monte Carlo approaches for the magnetocaloric effect in DyNi4Si

    NASA Astrophysics Data System (ADS)

    Laghrissi, Ayoub; Salmani, El Mehdi; Ez-Zahraouy, Hamid; Benyoussef, Abdelilah

    2016-08-01

    The magnetic and magnetocaloric properties of DyNi4Si alloys in YNi4Si-type orthorhombic structure have been investigated by using a combination of first-principles calculations and mean field theory, effective field theory, and Monte Carlo simulation. We find that Magnetic results of DyNi4Si compound show ferromagnetic-type ordering at 19 K, the magnetization-field isotherms for DyNi4Si exhibit hysteresis loop at 2 K due to strong magnetic anisotropy. The non-saturating behavior and the value of the magnetic moment of 7.7 μB/fu in 140 kOe at 2 K where the theoretical value for DyNi4Si only is about 10 μB, this suggest a not completely ordered ferromagnetic state of DyNi4Si (Morozkin et al., 2015) [2]. The isothermal entropy changes for H=14 T at T=22 K is -ΔS=15.6 J/(kg K). The obtained results are in good agreement with available experimental data. This study allows the suggestion of the compatible Ising model for a new class of compound YNi4Si-type, which shows magnetocaloric behavior at low temperature.

  13. Technology for the ERS-1 SAR antenna

    NASA Astrophysics Data System (ADS)

    Wagner, R.

    1984-09-01

    The metallization of CFRP waveguides, the Deployable Truss Structure (DTS) and verification in terrestrial environment of the 10 x 1 m SAR antenna of ERS-1 (ESA satellite) are discussed. Waveguide metallization was achieved indirectly with metallization of the mandrel prior to CFRP lay-up, and directly, by electroplating of manufactured CFRP components. Both techniques proved unsatisfactory, but a surface treatment applied to the metal layer in the indirect technique improves adhesion strength by an order of magnitude, and enables the waveguides to meet requirements. The DTS satisfies launch, deployment, and inflight specifications for a 5 panel/2 wing structure. Ground tests include analytical simulation of deployment with and without gravity effects, and a gravity compensation technique for tests.

  14. Final Technical Report for Award # ER64999

    SciTech Connect

    Metcalf, William W.

    2014-10-08

    This report provides a summary of activities for Award # ER64999, a Genomes to Life Project funded by the Office of Science, Basic Energy Research. The project was entitled "Methanogenic archaea and the global carbon cycle: a systems biology approach to the study of Methanosarcina species". The long-term goal of this multi-investigator project was the creation of integrated, multiscale models that accurately and quantitatively predict the role of Methanosarcina species in the global carbon cycle under dynamic environmental conditions. To achieve these goals we pursed four specific aims: (1) genome sequencing of numerous members of the Order Methanosarcinales, (2) identification of genomic sources of phenotypic variation through in silico comparative genomics, (3) elucidation of the transcriptional networks of two Methanosarcina species, and (4) development of comprehensive metabolic network models for characterized strains to address the question of how metabolic models scale with genetic distance.

  15. Experimental and theoretical study of the magnetic and structural properties of Er0.75Tb0.25Al2

    NASA Astrophysics Data System (ADS)

    Khan, Mahmud; Mudryk, Ya.; Paudyal, D.; Gschneidner, K. A., Jr.; Pecharsky, V. K.

    2010-08-01

    The Er0.75Tb0.25Al2 alloy has been investigated by x-ray powder diffraction, magnetization, and ac magnetic-susceptibility measurements. The low-field magnetization measured as a function of temperature indicates a ferromagnetic transition at ˜36K and another transition with thermal hysteresis at ˜18K . The ac magnetic-susceptibility measurements show frequency dependence below the ferromagnetic transition temperature, TC . Low-temperature x-ray powder-diffraction measurements suggest that although no structural transformation occurs around 18 K, a steplike anomaly in the lattice parameters does exist in the vicinity of the transition. First-principles electronic-structure calculations show anomalous density of states at the Fermi level. The results are comparable with the previously reported Er0.75Dy0.25Al2 alloy, thus supporting an earlier assumption that mixing two rare-earth ions with opposite signs of second-order Steven’s factor in RAl2 alloys creates a competition between the magnetoelastic and quadrupolar interactions, giving rise to multiple magnetic ordering phenomena.

  16. CW YVO4:Er Laser with Resonant Pumping

    NASA Astrophysics Data System (ADS)

    Gorbachenya, K. N.; Kisel, V. E.; Yasukevich, A. S.; Matrosov, V. N.; Tolstik, N. A.; Kuleshov, N. V.

    2015-05-01

    The lasing characteristics of a YVO4:Er laser with resonant pumping in the 1.5-1.6 μm range are studied. Lasing is obtained at λ = 1603 nm with a differential efficiency of up to 61%. YVO4:Er crystals are found to offer promise for use in efficient resonantly (in-band) pumped lasers.

  17. Reaction Diffusion Modeling of Calcium Dynamics with Realistic ER Geometry

    PubMed Central

    Means, Shawn; Smith, Alexander J.; Shepherd, Jason; Shadid, John; Fowler, John; Wojcikiewicz, Richard J. H.; Mazel, Tomas; Smith, Gregory D.; Wilson, Bridget S.

    2006-01-01

    We describe a finite-element model of mast cell calcium dynamics that incorporates the endoplasmic reticulum's complex geometry. The model is built upon a three-dimensional reconstruction of the endoplasmic reticulum (ER) from an electron tomographic tilt series. Tetrahedral meshes provide volumetric representations of the ER lumen, ER membrane, cytoplasm, and plasma membrane. The reaction-diffusion model simultaneously tracks changes in cytoplasmic and ER intraluminal calcium concentrations and includes luminal and cytoplasmic protein buffers. Transport fluxes via PMCA, SERCA, ER leakage, and Type II IP3 receptors are also represented. Unique features of the model include stochastic behavior of IP3 receptor calcium channels and comparisons of channel open times when diffusely distributed or aggregated in clusters on the ER surface. Simulations show that IP3R channels in close proximity modulate activity of their neighbors through local Ca2+ feedback effects. Cytoplasmic calcium levels rise higher, and ER luminal calcium concentrations drop lower, after IP3-mediated release from receptors in the diffuse configuration. Simulation results also suggest that the buffering capacity of the ER, and not restricted diffusion, is the predominant factor influencing average luminal calcium concentrations. PMID:16617072

  18. How to Avoid the ER If You Have Asthma

    MedlinePlus

    ... How to Avoid the ER if You Have Asthma KidsHealth > For Teens > How to Avoid the ER if You Have Asthma Print A A A Text Size What's in ... is the last resort for someone who has asthma. If a flare-up is really out of ...

  19. Competition of single-ion anisotropy of Sm and Dy ions during the spin-reorientation transition in (Nd1- x- y Sm x Dy y )(FeCo)B supermagnets

    NASA Astrophysics Data System (ADS)

    Kablov, E. N.; Ospennikova, O. G.; Piskorskii, V. P.; Korolev, D. V.; Kunitsyna, E. I.; Talantsev, A. D.; Morgunov, R. B.

    2016-07-01

    It has been found that an increase in the Sm concentration in the range x = 0.05-0.18 in (Nd1‒ x‒ y Sm x Dy y )(FeCo)B supermagnets leads to a shift in the spin-reorientation transition temperature to higher values, whereas a Dy addition results in a decrease in the transition temperature. Single-ion anisotropy of Sm and Dy ions has different symmetry, making contributions of opposite signs to the resulting magnetic anisotropy of the lattice. Therefore, the threshold temperature T S of the spin-reorientation transition, which is determined by the balance of magnetic anisotropies of sublattices, can be controlled using ions with different symmetries.

  20. Erbium induced magnetic properties of Er/ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Jayachandraiah, C.; Sivakumar, K.; Divya, A.; Krishnaiah, G.

    2016-05-01

    Pure and Er (2, 3 and 4 at. %) doped ZnO nanoparticles have been synthesized by chemical co-precipitation method. EDS spectrum confirmed the presence of Zn, O and Er in the synthesized samples. The XRD measurements confirmed the hexagonal wurtzite structure of ZnO for all samples. The crystallite size of the samples decreases with increase in concentration and are compatible with the results that obtained from TEM analysis.EPR spectra exhibitedferromagnetic signals the substitution Er The possible ferromagnetic zinc interstials signal is appeared for 2 at. % of Er dopant. The room temperature ferromagnetic is observed only for 2 at. % of Er while all other samples exhibiting weak ferromagnetic nature.

  1. 20 CFR 228.17 - Adjustments to the widow(er)'s, disabled widow(er)'s, surviving divorced spouse's, and remarried...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Adjustments to the widow(er)'s, disabled widow..., disabled widow(er)'s, surviving divorced spouse's, and remarried widow(er)'s tier I annuity amount. (a) If the employee died before attaining age 62 and after 1978 and the widow(er), disabled...

  2. 20 CFR 228.17 - Adjustments to the widow(er)'s, disabled widow(er)'s, surviving divorced spouse's, and remarried...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Adjustments to the widow(er)'s, disabled..., disabled widow(er)'s, surviving divorced spouse's, and remarried widow(er)'s tier I annuity amount. (a) If the employee died before attaining age 62 and after 1978 and the widow(er), disabled...

  3. 20 CFR 228.17 - Adjustments to the widow(er)'s, disabled widow(er)'s, surviving divorced spouse's, and remarried...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Adjustments to the widow(er)'s, disabled..., disabled widow(er)'s, surviving divorced spouse's, and remarried widow(er)'s tier I annuity amount. (a) If the employee died before attaining age 62 and after 1978 and the widow(er), disabled...

  4. 20 CFR 228.17 - Adjustments to the widow(er)'s, disabled widow(er)'s, surviving divorced spouse's, and remarried...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Adjustments to the widow(er)'s, disabled widow..., disabled widow(er)'s, surviving divorced spouse's, and remarried widow(er)'s tier I annuity amount. (a) If the employee died before attaining age 62 and after 1978 and the widow(er), disabled...

  5. 20 CFR 228.17 - Adjustments to the widow(er)'s, disabled widow(er)'s, surviving divorced spouse's, and remarried...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Adjustments to the widow(er)'s, disabled..., disabled widow(er)'s, surviving divorced spouse's, and remarried widow(er)'s tier I annuity amount. (a) If the employee died before attaining age 62 and after 1978 and the widow(er), disabled...

  6. Electrical characteristics of DyBCO coated conductors at high current densities for fault current limiter application

    NASA Astrophysics Data System (ADS)

    Therasse, M.; Decroux, M.; Antognazza, L.; Abplanalp, M.; Fischer, Ø.

    2008-10-01

    We report on the electrical and thermal characterisation of DyBa 2Cu 3O 7 (DyBCO) coated conductors. Detailed I- V curves of these coated conductors are presented showing that the flux flow resistivity of these CC is 2-3 orders of magnitude higher than the one observed in HTS thin films grown onto sapphire substrates. This high flux flow resistivity, which might reflect the presence of grain boundaries, influences the switching behaviour of the superconducting line. The thermal characteristics of these coated conductors have been investigated on two aspects; the propagation velocity of the normal zone and the heating of the line. The propagation velocity is very low of the order of cm/s and a very fast increasing of the temperature of DyBCO switched line is observed. From all these measurements, the electrical and thermal behaviour of the coated conductors will be discussed.

  7. Slow and static spin correlations in Dy(2 + x)Ti(2 - x)O(7 - δ).

    PubMed

    Gardner, J S; Ehlers, G; Fouquet, P; Farago, B; Stewart, J R

    2011-04-27

    The static and dynamic spin correlations in the spin ices Dy(2.3)Ti(1.7)O(6.85) and Dy(2)Ti(2)O(7) have been studied in polarized neutron diffraction and neutron spin echo experiments. The measurements reveal that, below 100 mK, the magnetic scattering broadens and shifts to higher |Q| upon stuffing the pyrochlore lattice with additional Dy(3+) ions. These observations can be related, by means of reverse Monte Carlo simulation, to the modified distribution of near-neighbour distances and an overall more antiferromagnetic character of the near-neighbour couplings. The dynamic measurements show that the spin correlations are slower in the stuffed system. These results will be discussed and compared to the holmium analogues. PMID:21471620

  8. THEORETICAL RESEARCH OF THE OPTICAL SPECTRA AND EPR PARAMETERS FOR Cs2NaYCl6:Dy3+ CRYSTAL

    NASA Astrophysics Data System (ADS)

    Dong, Hui-Ning; Dong, Meng-Ran; Li, Jin-Jin; Li, Deng-Feng; Zhang, Yi

    2013-09-01

    The calculated EPR parameters are in reasonable agreement with the observed values. The important material Cs2NaYCl6 doped with rare earth ions have received much attention because of its excellent optical and magnetic properties. Based on the superposition model, in this paper the crystal field energy levels, the electron paramagnetic resonance parameters g factors of Dy3+ and hyperfine structure constants of 161Dy3+ and 163Dy3+ isotopes in Cs2NaYCl6 crystal are studied by diagonalizing the 42 × 42 energy matrix. In the calculations, the contributions of various admixtures and interactions such as the J-mixing, the mixtures among the states with the same J-value, and the covalence are all considered. The calculated results are in reasonable agreement with the observed values. The results are discussed.

  9. Effect of crystal grain dimension on the magnetic properties and magnetocaloric effects in DyCuAl compound.

    PubMed

    Dong, Qiaoyan; Shen, Baogen; He, Shuli; Jiang, Hongwei; Zheng, Wu; Sun, Jirong

    2012-02-01

    The influence of crystal grain dimension (approximately 38 nm and approximately 90 nm) on magnetic properties and magnetocaloric effects has been investigated for DyCuAl compound. The reduction of crystal grain dimension leads to the decrease of the Curie temperature (from 27 K to 24 K) and the evident enhancement of magnetic anisotropy. The peak values of magnetic entropy change under a field change of 0-5 T are 14.9 J kg(-1) K(-1) and 20.4 J kg(-1) K(-1) for DyCuAl compounds (approximately 38 nm and approximately 90 nm), respectively. A large refrigerant capacity is also produced in DyCuAl compounds (423 J kg(-1) and 379 J kg(-1) for the same field change, respectively). Large magnetic entropy changes and refrigerant capacities jointly make them attractive candidates for low-temperature magnetic refrigerant. PMID:22629891

  10. Influence of Dy and Cu doping on the room temperature multiferroic properties of BiFeO3

    NASA Astrophysics Data System (ADS)

    Priya, A. Sathiya; Banu, I. B. Shameem; Anwar, Shahid

    2016-03-01

    A series of Bi1-xDyxFe0.98Cu0.02O3 (x=1%, 2%, 3%, 4%, 5%) nanoparticles were prepared by sol-gel method. X-ray diffraction patterns reveal that the undoped and doped samples crystallize in rhombohedral structure. Enhanced magnetic properties are observed for the doped nanoparticles as compared to undoped BiFeO3 (BFO) and when Dy substitution to Bi site is increased, the saturation magnetization (Ms) and remnant magnetization (Mr) show a remarkable increase. The Dy and Cu doping has improved the ferroelectric properties of the BFO. The measured magnetoelectric effect shows remarkable enhancement for the doped BFO as compared to the undoped BFO. The measured magnetic and ferroelectric properties of the doped samples has demonstrated that Dy and Cu doping can significantly improve the multiferroic properties of BiFeO3.

  11. Enhanced DySEM imaging of cantilever motion using artificial structures patterned by focused ion beam techniques

    NASA Astrophysics Data System (ADS)

    Schröter, M.-A.; Ritter, M.; Holschneider, M.; Sturm, H.

    2016-03-01

    We use a dynamic scanning electron microscope (DySEM) to map the spatial distribution of the vibration of a cantilever beam. The DySEM measurements are based on variations of the local secondary electron signal within the imaging electron beam diameter during an oscillation period of the cantilever. For this reason, the surface of a cantilever without topography or material variation does not allow any conclusions about the spatial distribution of vibration due to a lack of dynamic contrast. In order to overcome this limitation, artificial structures were added at defined positions on the cantilever surface using focused ion beam lithography patterning. The DySEM signal of such high-contrast structures is strongly improved, hence information about the surface vibration becomes accessible. Simulations of images of the vibrating cantilever have also been performed. The results of the simulation are in good agreement with the experimental images.

  12. XPS study of the chemical stability of DyBa2Cu3O6+δ superconductor

    NASA Astrophysics Data System (ADS)

    Fetisov, A. V.; Kozhina, G. А.; Estemirova, S. Kh.; Fetisov, V. B.; Gulyaeva, R. I.

    2015-01-01

    The chemical stability of the powder DyBa2Cu3O6+δ has been studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermal analysis at ambient conditions. The powder was subjected to mechanical processing in a ball mill-activator to accelerate chemical degradation. The kinetic regularities of hydrolytic decomposition of DyBa2Cu3O6+δ under the influence of air moisture have been determined. The resistive properties of DyBa2Cu3O6+δ to water have been found to be better, but not much different from analogous properties of YBa2Cu3O6+δ which is unstable in a wet environment. Chemical degradation of the material is triggered by crucial concentrating of water particles near the free surface of the solid reactant (due to their low diffusibility in the bulk) leading to rapid chemical decomposition of the respective regions.

  13. Slow and static spin correlations in Dy(2+x)Ti(2-x)O(7-d)

    SciTech Connect

    Gardner, Jason; Ehlers, Georg; Fouquet, Peter; Farago, Bela; Stewart, John Ross

    2011-01-01

    The static and dynamic spin correlations in the spin ices Dy{sub 2.3}Ti{sub 1.7}O{sub 6.85} and Dy{sub 2}Ti{sub 2}O{sub 7} have been studied in polarized neutron diffraction and neutron spin echo experiments. The measurements reveal that, below 100 mK, the magnetic scattering braodens and shifts to higher |Q| upon stuffing the pyrochlore lattice with additional Dy{sup 3+} ions. These observations can be related, by means of reverse Monte Carlo simulation, to the modified distribution of near-neighbour distances and an overall more antiferromagnetic character of the near-neighbour couplings. The dynamic measurements show that the spin correlations are slower in the stuffed system. These results will be discussed and compared to the holmium analogues.

  14. GRP78 Interacting Partner Bag5 Responds to ER Stress and Protects Cardiomyocytes From ER Stress-Induced Apoptosis.

    PubMed

    Gupta, Manish K; Tahrir, Farzaneh G; Knezevic, Tijana; White, Martyn K; Gordon, Jennifer; Cheung, Joseph Y; Khalili, Kamel; Feldman, Arthur M

    2016-08-01

    Bag5 is a member of the BAG family of molecular chaperone regulators and is unusual in that it consists of five BAG domains, which function as modulators of chaperone activity. Bag family proteins play a key role in cellular as well as in cardiac function and their differential expression is reported in heart failure. In this study, we examined the importance of a Bag family member protein, Bag5, in cardiomyocytes during endoplasmic reticulum (ER) stress. We found that expression of Bag5 in cardiomyocytes is significantly increased with the induction of ER stress in a time dependent manner. We have taken gain-in and loss-of functional approaches to characterize Bag5 protein function in cardiomyocytes. Adenoviral mediated expression of Bag5 significantly decreased cell death as well as improved cellular viability in ER stress. Along with this, ER stress-induced CHOP protein expression is significantly decreased in cells that overexpress Bag5. Conversely, we found that siRNA-mediated knockdown of Bag5 caused cell death, increased cytotoxicity, and decreased cellular viability in cardiomyocytes. Mechanistically, we found that Bag5 protein expression is significantly increased in the ER during ER stress and that this in turn modulates GRP78 protein stability and reduces ER stress. This study suggests that Bag5 is an important regulator of ER function and so could be exploited as a tool to improve cardiomyocyte function under stress conditions. J. Cell. Biochem. 117: 1813-1821, 2016. © 2016 Wiley Periodicals, Inc. PMID:26729625

  15. Dy{sup 3+}-doped Ga–Sb–S chalcogenide glasses for mid-infrared lasers

    SciTech Connect

    Zhang, Mingjie; Yang, Anping; Peng, Yuefeng; Zhang, Bin; Ren, He; Guo, Wei; Yang, Yan; Zhai, Chengcheng; Wang, Yuwei; Yang, Zhiyong; Tang, Dingyuan

    2015-10-15

    Highlights: • Novel Ga–Sb–S chalcogenide glasses doped with Dy{sup 3+} ions were synthesized. • The glasses show good thermal stability and excellent infrared transparency. • The glasses show low phonon energy and intense mid-infrared emissions. • The mid-infrared emissions have high quantum efficiency. • The mid-infrared emissions have large stimulated emission cross sections. - Abstract: Novel Ga–Sb–S chalcogenide glasses doped with different amount of Dy{sup 3+} ions were prepared. Their thermal stability, optical properties, and mid-infrared (MIR) emission properties were investigated. The glasses show good thermal stability, excellent infrared transparency, very low phonon energy (∼306 cm{sup −1}), and intense emissions centered at 2.95, 3.59, 4.17 and 4.40 μm. Three Judd–Ofelt intensity parameters (Ω{sub 2} = 8.51 × 10{sup −20} cm{sup 2}, Ω{sub 4} = 2.09 × 10{sup −20} cm{sup 2}, and Ω{sub 6} = 1.60 × 10{sup −20} cm{sup 2}) are obtained, and the related radiative transition properties are evaluated. The high quantum efficiencies and large stimulated emission cross sections of the MIR emissions (88.10% and 1.11 × 10{sup −20} cm{sup 2} for 2.95 μm emission, 75.90% and 0.38 × 10{sup −20} cm{sup 2} for 4.40 μm emission, respectively) in the Dy{sup 3+}-doped Ga–Sb–S glasses make them promising gain materials for the MIR lasers.

  16. An overview of sea state conditions and air-sea fluxes during RaDyO

    NASA Astrophysics Data System (ADS)

    Zappa, Christopher J.; Banner, Michael L.; Schultz, Howard; Gemmrich, Johannes R.; Morison, Russel P.; Lebel, Deborah A.; Dickey, Tommy

    2012-07-01

    Refining radiative-transfer modeling capabilities for light transmission through the sea surface requires a more detailed prescription of the sea surface roughness beyond the probability density function of the sea surface slope field. To meet this need, exciting new measurement methodologies now provide the opportunity to enhance present knowledge of sea surface roughness, especially at the microscale. In this context, two intensive field experiments using R/PFloating Instrument Platformwere staged within the Office of Naval Research's Radiance in a Dynamic Ocean (RaDyO) field program in the Santa Barbara Channel and in the central Pacific Ocean south of Hawaii. As part of this program, our team gathered and analyzed a comprehensive suite of sea surface roughness measurements designed to provide optimal coverage of fundamental optical distortion processes associated with the air-sea interface. This contribution describes the ensemble of instrumentation deployed. It provides a detailed documentation of the ambient environmental conditions that prevailed during the RaDyO field experiments. It also highlights exciting new sea surface roughness measurement capabilities that underpin a number of the scientific advances resulting from the RaDyO program. For instance, a new polarimetric imaging camera highlights the complex interplay of wind and surface currents in shaping the roughness of the sea surface that suggests the traditional Cox-Munk framework is not sufficient. In addition, the breaking crest length spectral density derived from visible and infrared imagery is shown to be modulated by the development of the wavefield (wave age) and alignment of wind and surface currents at the intermediate (dominant) scale of wave breaking.

  17. UV–Optical Observation of Type Ia Supernova SN 2013dy in NGC 7250

    NASA Astrophysics Data System (ADS)

    Zhai, Qian; Zhang, Ju-Jia; Wang, Xiao-Feng; Zhang, Tian-Meng; Liu, Zheng-Wei; Brown, Peter J.; Huang, Fan; Zhao, Xu-Lin; Chang, Liang; Yi, Wei-Min; Wang, Chuan-Jun; Xin, Yu-Xin; Wang, Jian-Guo; Lun, Bao-Li; Zhang, Xi-Liang; Fan, Yu-Feng; Zheng, Xiang-Ming; Bai, Jin-Ming

    2016-05-01

    Extensive and independent observations of Type Ia supernova (SN Ia) SN 2013dy are presented, including a larger set of UBVRI photometry and optical spectra from a few days before the peak brightness to ∼ 200 days after explosion, and ultraviolet (UV) photometry spanning from t ≈ –10 days to t ≈ +15 days refers to the B band maximum. The peak brightness (i.e., MB = –19.65 ± 0.40 mag; Lmax = [1.95 ± 0.55] × 1043 erg s‑1) and the mass of synthesized 56Ni (i.e., M(56Ni) = 0.90 ± 0.26 M⊙) are calculated, and they conform to the expectation for an SN Ia with a slow decline rate (i.e., Δm15(B) = 0.90 ± 0.03 mag). However, the near infrared (NIR) brightness of this SN (i.e., MH = –17.33 ± 0.30 mag) is at least 1.0 mag fainter than usual. Besides, spectroscopy classification reveals that SN 2013dy resides on the border of “core normal” and “shallow silicon” subclasses in the Branch et al. classification scheme, or on the border of the “normal velocity” SNe Ia and 91T/99aa-like events in the Wang et al. system. These suggest that SN 2013dy is a slow-declining SN Ia located on the transitional region of nominal spectroscopic subclasses and might not be a typical normal sample of SNe Ia.

  18. Structural and luminescence studies on Dy3+ doped lead boro-telluro-phosphate glasses

    NASA Astrophysics Data System (ADS)

    Selvi, S.; Venkataiah, G.; Arunkumar, S.; Muralidharan, G.; Marimuthu, K.

    2014-12-01

    This paper reports results obtained on the structural and luminescence properties of Dy3+doped lead boro-telluro-phosphate glasses prepared following the melt quenching technique. FTIR spectra exhibit the presence of B-O vibrations, P-O-P symmetric vibrations and Te-O stretching modes of TeO3 and TeO6 units. The metal-ligand bond was identified through UV-vis-NIR absorption spectra and to determine the band tailing parameter, direct and indirect band gap energy of the prepared glasses. The Judd-Ofelt (JO) intensity parameters (Ω2, Ω4 and Ω6), experimental and theoretical oscillator strengths were also determined and reported. Luminescence measurements were made to determine the transition probability (A), stimulated emission cross-section (σPE) and branching ratio (βR) for the transitions that include 4F9/2→6H11/2, 6H13/2 and 6H15/2 bands. The effect of Dy3+ ion concentration on the intensity ratio of yellow to blue emission bands has also been studied and reported. The lifetime corresponding to the 4F9/2 level of the title glasses has been found to decrease with the increase in Dy3+ ion concentration. The chromaticity coordinates (x,y) have been estimated from the luminescence spectra and the suitability of title glasses for white light applications has been analyzed using CIE chromaticity diagram. The variation of optical properties with the concentration of dysprosium oxide content in the glasses have been studied and reported.

  19. Refrustration and competing orders in the prototypical Dy2Ti2O7 spin ice material

    NASA Astrophysics Data System (ADS)

    Henelius, P.; Lin, T.; Enjalran, M.; Hao, Z.; Rau, J. G.; Altosaar, J.; Flicker, F.; Yavors'kii, T.; Gingras, M. J. P.

    2016-01-01

    Spin ices, frustrated magnetic materials analogous to common water ice, have emerged over the past 15 years as exemplars of high frustration in three dimensions. Recent experimental developments aimed at interrogating anew the low-temperature properties of these systems, in particular whether the predicted transition to long-range order occurs, behoove researchers to scrutinize our current dipolar spin ice model description of these materials. In this work, we do so by combining extensive Monte Carlo simulations and mean-field theory calculations to analyze data from previous magnetization, diffuse neutron scattering, and specific-heat measurements on the paradigmatic Dy2Ti2O7 spin ice material. In this work, we also reconsider the possible importance of the nuclear specific heat Cnuc in Dy2Ti2O7 . We find that Cnuc is not entirely negligible below a temperature ˜0.5 K and must therefore be taken into account in a quantitative analysis of the calorimetric data of this compound below that temperature. We find that in this material, small effective spin-spin exchange interactions compete with the magnetostatic dipolar interaction responsible for the main spin ice phenomenology. This causes an unexpected "refrustration" of the long-range order that would be expected from the incompletely self-screened dipolar interaction and which positions the material at the boundary between two competing classical long-range-ordered ground states. This allows for the manifestation of new physical low-temperature phenomena in Dy2Ti2O7 , as exposed by recent specific-heat measurements. We show that among the four most likely causes for the observed upturn of the specific heat at low temperature [an exchange-induced transition to long-range order, quantum non-Ising (transverse) terms in the effective spin Hamiltonian, the nuclear hyperfine contribution, and random disorder], only the last appears to be reasonably able to explain the calorimetric data.

  20. Degradation of hydrogen sulfide by Xanthomonas sp. strain DY44 isolated from peat

    SciTech Connect

    Cho, Kyeoungsuk; Hirai, Mitsuyo; Shoda, Makoto )

    1992-04-01

    Xanthomonas sp. strain DY44, capable of degrading H{sub 2}S, was isolated from dimethyl disulfide-acclimated peat. This bacterium removed H{sub 2}S either as a single gas or in the presence of the sulfur-containing compounds methanethiol, dimethyl sulfide, and dimethyl disulfide. The maximum specific H{sub 2}S removal rate, obtained in the late stationary phase, was 3.92 mmol g of dry cells{sup {minus}1}h{sup {minus}1} (6.7 {times} 10{sup {minus}16} mol cell{sup {minus}1}h{sup {minus}1}) at pH 7 and 30C through a batch experiment in a basal mineral medium. Since Xanthomonas sp. Strain DY44 exhibited no autotrophic growth with H{sub 2}S, the H{sub 2}S removal was judged not to be a consequence of chemolithotrophic activity. By using x-ray photoelectron spectroscopy, the metabolic product of H{sub 2}S oxidation was determined to be polysulfide, which has properties very similar to those of elemental sulfur. Autoclaved cells (120C, 20 min) did not show H{sub 2}S degradation, but cells killed by {gamma}-irradiation and cell extracts both oxidized H{sub 2}S, suggesting the existence of a heat-labile intracellular enzymatic system for H{sub 2}S oxidation. When Xanthomonas sp. strain DY44 was inoculated into fibrous peat, this strain degraded H{sub 2}S without lag time, suggesting that it will be a good candidate for maintaining high H{sub 2}S removability in the treatment of exhaust gases.

  1. Supercooled spin liquid state in the frustrated pyrochlore Dy2Ti2O7

    DOE PAGESBeta

    Kassner, Ethan R.; Eyvazov, Azar B.; Pichler, Benjamin; Munsie, Timothy J. S.; Dabkowska, Hanna A.; Luke, Graeme M.; Davis, J. C. Seamus

    2015-06-30

    A “supercooled” liquid develops when a fluid does not crystallize upon cooling below its ordering temperature. Instead, the microscopic relaxation times diverge so rapidly that, upon further cooling, equilibration eventually becomes impossible and glass formation occurs. Classic supercooled liquids exhibit specific identifiers including microscopic relaxation times diverging on a Vogel–Tammann–Fulcher (VTF) trajectory, a Havriliak–Negami (HN) form for the dielectric function ε(ω,T), and a general Kohlrausch–Williams–Watts (KWW) form for time-domain relaxation. Recently, the pyrochlore Dy2Ti2O7 has become of interest because its frustrated magnetic interactions may, in theory, lead to highly exotic magnetic fluids. However, its true magnetic state at low temperaturesmore » has proven very difficult to identify unambiguously. Here, we introduce high-precision, boundary-free magnetization transport techniques based upon toroidal geometries and gain an improved understanding of the time- and frequency-dependent magnetization dynamics of Dy2Ti2O7. We demonstrate a virtually universal HN form for the magnetic susceptibility χ(ω,T), a general KWW form for the real-time magnetic relaxation, and a divergence of the microscopic magnetic relaxation rates with the VTF trajectory. Low-temperature Dy2Ti2O7 therefore exhibits the characteristics of a supercooled magnetic liquid. Lastly, one implication is that this translationally invariant lattice of strongly correlated spins may be evolving toward an unprecedented magnetic glass state, perhaps due to many-body localization of spin.« less

  2. Crystalline, Magnetic and Electronic Structure of the Ba2DySbO6 Complex Perovskite

    NASA Astrophysics Data System (ADS)

    Cardona, R.; Moreno Mendoza, R.; Carrero Bermúdez, L. A.; Landínez Téllez, D. A.; Roa-Rojas, J.

    2016-01-01

    In this work, we report the synthesis of the Ba2DySbO6 new double perovskite by means of the solid-state reaction recipe from high-purity oxide powders of BaCO3, Dy2O3, and Sb2O5. The analysis of the crystal structure was carried out through the X-ray diffraction technique with posterior Rietveld refinement of the experimental diffraction data by the GSAS code. Results reveal that the Ba2DySbO6 material crystallizes in a rhombohedral perovskite structure, belonging to the R-3 (#148) space group with lattice parameter a = 5.96260(5) Å, and angle α = 60.008°. The magnetic characterization was performed by measurements of magnetic susceptibility as a function of temperature. The behavior observed in the temperature regime from 4 K up to 300 K was paramagnetic. The characteristic magnetic parameters were obtained from the fitting with the Curie equation, obtaining the values of susceptibility independent of temperature 0.00633 emu/mol and effective magnetic moment 8.9 \\upmu B, which is 84 % in agreement with the expected value predicted by the Hund's rules. The electronic structure was calculated by means of linearized augmented plane waves in the framework of the density functional theory (DFT). This study considers the cohesion energies as a function of the lattice parameter, with a lattice constant a, whose value is 98 % in agreement with the experimental result. Curves of density of states as a function of the wave number reveal that this material behaves as an insulator with energy gap 3.65 eV. This result was corroborated by diffuse reflectance experiments adjusted to the Kubelka-Munk equation. The effective magnetic moment obtained from the DFT calculations was 7.7 \\upmu B.

  3. Metamagnetic behaviors in RRu2Al10(R = Tb, Dy, Ho) single crystals

    NASA Astrophysics Data System (ADS)

    Mizushima, Toshio; Watanabe, Yuuya; Ejiri, Jun-ichi; Kuwai, Tomohiko; Isikawa, Yosikazu

    2015-03-01

    We measured the magnetization M and the specific heat C of TbRu2Al10, DyRu2Al10 and HoRu2Al10 single crystals. We observed antiferromagnetic transitions at the temperature T = 15 K for TbRu2Al10, 6.5 and 5.1 K for DyRu2Al10 and 5.0 K for HoRu2Al10 in the temperature dependences of M divided by the applied magnetic field, M/H. The magnetization curves exhibit metamagnetic behaviors below their magnetic transitions of all materials. M of TbRu2Al10 at T = 2 K along the c-axis shows the metamagnetic behavior at H = 1.2, 1.6 and 3.2 T and shows a complex behavior with small jumps around H = 4, 5 and 6.2 T along the a-axis. As for DyRu2Al10, the metamgnetic behaviors were observed at H = 0.16, 1.35 and 1.8 T along the c-axis. In addition to the magnetic transitions at T = 5.1 and 6.5 K, we observed an unusual drop around 2 K in the temperature dependence of M/H and correspondingly a kink in the magnetic specific heat at T = 1.5 K. As for the specific heat of HoRu2Al10, an upturn due to a nuclear contribution in the specific heat was observed below 1.5 K.

  4. Enhanced Emission from Li2CaSiO4:Dy3+ Phosphors by Doping with Al3+ and B3+

    NASA Astrophysics Data System (ADS)

    Erdoğmuş, E.

    2016-05-01

    Pure Li2CaSiO4, Li2CaSiO4:Dy3+ and Al3+, B3+ co-doped materials were prepared by a solid-state reaction in air at 900°C for 6 h and characterized by using powder XRD. The luminescence properties of the synthesized phosphors were measured at room temperature with a spectrofluorometer. Li2CaSiO4:Dy3+ emits at 484, 575, and 660 nm upon 352 nm excitation. The emission spectrum intensity of Dy3+ increased from 0.01 to 0.06 mol.%, and beyond 0.06 mol.%, concentration quenching was observed. Also, in this study, the effects of boric acid and aluminum oxide concentration on the photoluminescence properties of Dy3+ doped phosphors were investigated. The results showed that boric acid and aluminum oxide were effective in improving the photoluminescence intensity of Li2CaSiO4:Dy3+ compounds.

  5. Effect of sintering conditions on the magnetic and microstructural properties of Nd-Fe-B sintered magnets doped with DyF(3) powders.

    PubMed

    Park, Song-E; Kim, Tae-Hoon; Lee, Seong-Rae; Namkung, Seok; Jang, Tae-Suk

    2012-04-01

    The microstructural and magnetic property changes of DyF(3)-doped (Nd(26.06), Dy(6.51))-Fe(bal) -B(0.97)-M(2.39) (wt. %) (M = Cu, Al, Co, and Nb) sintered magnets as functions of the sintering conditions were studied. The sintering conditions for the optimum core-shell microstructure were determined. When the magnets were sintered at 1050 °C for 4 h, a coercivity of 35.1 kOe was obtained without sacrificing the remanence. When the magnets were doped with DyF(3), the formation of the RE-rich phase (Nd-Dy-O) was effectively suppressed and, hence, saving the Dy. In addition, the formation of a cubic-NdOF triple-junction phase (TJP) improves the interface uniformity and enhances the coercivity. PMID:22412217

  6. Effect of sintering conditions on the magnetic and microstructural properties of Nd-Fe-B sintered magnets doped with DyF3 powders

    NASA Astrophysics Data System (ADS)

    Park, Song-E.; Kim, Tae-Hoon; Lee, Seong-Rae; Namkung, Seok; Jang, Tae-Suk

    2012-04-01

    The microstructural and magnetic property changes of DyF3-doped (Nd26.06, Dy6.51)-Febal -B0.97-M2.39 (wt. %) (M = Cu, Al, Co, and Nb) sintered magnets as functions of the sintering conditions were studied. The sintering conditions for the optimum core-shell microstructure were determined. When the magnets were sintered at 1050 °C for 4 h, a coercivity of 35.1 kOe was obtained without sacrificing the remanence. When the magnets were doped with DyF3, the formation of the RE-rich phase (Nd-Dy-O) was effectively suppressed and, hence, saving the Dy. In addition, the formation of a cubic-NdOF triple-junction phase (TJP) improves the interface uniformity and enhances the coercivity.

  7. Atomic-Resolution X-ray Energy-Dispersive Spectroscopy Chemical Mapping of Substitutional Dy Atoms in a High-Coercivity Neodymium Magnet

    NASA Astrophysics Data System (ADS)

    Itakura, Masaru; Watanabe, Natsuki; Nishida, Minoru; Daio, Takeshi; Matsumura, Syo

    2013-05-01

    We have investigated local element distributions in a Dy-doped Nd2Fe14B hot-deformed magnet by atomic-column resolution chemical mapping using an X-ray energy-dispersive spectrometer (XEDS) attached to an aberration-corrected scanning transmission electron microscope (Cs-corrected STEM). The positions of the Nd and Dy atomic columns were visualized in the XEDS maps. The substitution of Dy was limited to a surface layer 2-3 unit cells thick in the Nd2Fe14B grains, and the Dy atoms preferentially occupied the 4f-Nd sites of Nd2Fe14B. These results provide further insights into the principal mechanism governing the coercivity enhancement due to Dy doping.

  8. Synthesis and photoluminescence properties of near-UV pumped yellow-emitting Li3Ba2La3(WO4)8:Dy3+ phosphors

    NASA Astrophysics Data System (ADS)

    Wang, G. Q.; Gong, X. H.; Chen, Y. J.; Huang, J. H.; Lin, Y. F.; Luo, Z. D.; Huang, Y. D.

    2014-05-01

    Li3Ba2La3(WO4)8:Dy3+ yellow-emitting phosphors were synthesized by the solid state reaction method. These phosphors exhibit one intense emission band around 575 nm under excitation at 365 nm. The dependences of the emission intensities and the chromaticity coordinates on Dy3+ concentration were analyzed. The optimum doping concentration of Dy3+ for the phosphor is about 6 mol% and the corresponding chromaticity coordinates is (0.435, 0.476) at room temperature. Besides, the Li3Ba2La3(WO4)8:Dy3+ phosphor shows higher thermal stability than that of (Sr, Ba)2SiO4:Eu2+. The results show that the Li3Ba2La3(WO4)8:Dy3+ phosphor with strong yellow emission may be applied in near ultraviolet pumped white LEDs.

  9. Up Conversion Measurements in Er:YAG; Comparison with 1.6 Micrometer Laser Performance

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.; Walsh, Brian M.; Amzajerdian, Farzin; Reichle, Donald J.; Busch, George E.; Carrion, William A.

    2011-01-01

    Up conversion significantly affects Er:YAG lasers. Measurements performed here for low Er concentration are significantly different than reported high Er concentration. The results obtained here are used to predict laser performance and are compared with experimental results.

  10. Evaluation of the dosimetric response for CaSO4:Dy at low temperature.

    PubMed

    Cruz-Zaragoza, E; Ramos-Bernal, S; Negrón-Mendoza, A; Azoŕin, J

    2002-01-01

    Homemade solid state CaSO4:Dy detectors were tested to evaluate their response to gamma radiation at liquid nitrogen temperature (77 K). The dosemeters were irradiated with doses between 12 and 1071 Gy. For this study these dosemeters were exposed to gamma rays with a dose rate of 1.19 Gy.min(-1). The analysis for these crystals was made by thermoluminiscence. The dose response at liquid nitrogen temperature was linear in the dose range studied and it is about 20% lower with respect to the response at room temperature. The response is reproducible with the same geometric set-up. PMID:12382918

  11. Investigation of the thermal properties on Dy5Ge2Si2

    NASA Astrophysics Data System (ADS)

    Shanmukharao Samatham, S.; Venkateshwarlu, D.; Gangrade, Mohan; Pandya, Swati; Ganesan, V.

    2014-09-01

    The calorimetric and thermopower measurements on Dy5Ge2Si2 are presented. The antiferromagnetic ordering resulted in a sharp peak in specific heat and paramagnetic temperature as a shoulder. Magnetic entropy (Smag) is estimated from the magnetic heat capacity, Cmag and is in good agreement with the theoretically calculated value. A small note on correct assessment of Smag is presented. Thermoelectric power is analysed in line with the specific heat and a temperature region of magnetic correlations is identified. Charge carrier density n~2.5x1023 cm-3 is calculated using Sommerfeld parameter γ and diffusion thermopower constant σD.

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

    NASA Astrophysics Data System (ADS)

    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

  13. Calculation of a plasma HgDyI{sub 3} transport coefficients

    SciTech Connect

    Hajji, S.; HadjSalah, S.; Benhalima, A.; Charrada, K.; Zissis, G.

    2015-05-15

    This work is devoted to the calculation of the chemical composition and transport coefficients of HgDyI{sub 3} plasmas in thermal equilibrium. These calculations are performed for pressures equal to 2MP and for temperatures varying from 1000 to 10 000 K. The thermal and electrical conductivity as well as viscosity have been computed as a function of temperature at different atomic ratios. The computational method proposed by Devoto from the classical formalism described by Hirschfelder et al. [Molecular Theory of Gases and Liquids (John Wiley and Sons, New York, 1954)] is used.

  14. d sigma/dy Distribution of Drell-Yan Dielectron Pairs

    SciTech Connect

    Han, Jiyeon; Bodek, A.; Sakumoto, W.; Chung, Y.; /Rochester U.

    2007-11-01

    The authors report on the measurement of the rapidity distribution, d{sigma}/dY, over the full kinematic range for e{sup +}e{sup -} pairs produced in p{bar p} collisions at {radical}s = 1.96 TeV in the Z boson region of 66 < M{sub ee} < 116 GeV/c{sup 2}. The data sample consists of 1.1 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV taken by the Collider Detector at Fermilab (CDF). The d{sigma}/dy is compared with the NLO theory prediction.

  15. Planar tetranuclear lanthanide clusters with the Dy4 analogue displaying slow magnetic relaxation.

    PubMed

    Langley, Stuart K; Chilton, Nicholas F; Gass, Ian A; Moubaraki, Boujemaa; Murray, Keith S

    2011-12-21

    Two isostructural tetranuclear lanthanide clusters of general formula [Ln(III)(4)(μ(3)-OH)(2)(o-van)(4)(O(2)CC(CH(3))(3))(4)(NO(3))(2)]·CH(2)Cl(2)·1.5H(2)O (Ln = Gd (1) and Dy (2)) (o-van = 3-methoxysalicylaldehydato anion) are reported. The metallic cores of both complexes display a planar 'butterfly' arrangement. Magnetic studies show that both are weakly coupled, with 2 displaying probable SMM behaviour. PMID:22031449

  16. Competition of magnetization mechanisms in (NdDy)(FeCo)B alloys, doped with samarium

    NASA Astrophysics Data System (ADS)

    Kablov, E. N.; Ospennikova, O. G.; Piskorskii, V. P.; Korolev, D. V.; Kunitsina, E. I.; Dmitriev, A. I.; Morgunov, R. B.

    2016-01-01

    It is found that magnetic hysteresis in sintered magnets (Nd0.62Dy0.33Sm0.05)16.2(Fe0.77Co0.23)78.1B5.7 for the temperature range T = 150-350 K, is caused by a mechanism associated with the displacement of domain walls, which ceases at temperatures below 150 K. In addition, the formation of magnetic hysteresis in this temperature range is affected by the mechanism involving the nucleation of the reverse magnetization phase, which is observed at temperatures down to 36 K.

  17. Control of the Ultrafast Photoinduced Magnetization across the Morin Transition in DyFeO_{3}.

    PubMed

    Afanasiev, D; Ivanov, B A; Kirilyuk, A; Rasing, Th; Pisarev, R V; Kimel, A V

    2016-03-01

    Excitation of the collinear compensated antiferromagnet DyFeO_{3} with a single 60 fs laser pulse triggers a phase transition across the Morin point into a noncollinear spin state with a net magnetization. Time-resolved imaging of the magnetization dynamics of this process reveals that the pulse first excites the spin oscillations upon damping of which the noncollinear spin state emerges. The sign of the photoinduced magnetization is defined by the relative orientation of the pump polarization and the direction of the antiferromagnetic vector in the initial collinear spin state. PMID:26991201

  18. Control of the Ultrafast Photoinduced Magnetization across the Morin Transition in DyFeO3

    NASA Astrophysics Data System (ADS)

    Afanasiev, D.; Ivanov, B. A.; Kirilyuk, A.; Rasing, Th.; Pisarev, R. V.; Kimel, A. V.

    2016-03-01

    Excitation of the collinear compensated antiferromagnet DyFeO3 with a single 60 fs laser pulse triggers a phase transition across the Morin point into a noncollinear spin state with a net magnetization. Time-resolved imaging of the magnetization dynamics of this process reveals that the pulse first excites the spin oscillations upon damping of which the noncollinear spin state emerges. The sign of the photoinduced magnetization is defined by the relative orientation of the pump polarization and the direction of the antiferromagnetic vector in the initial collinear spin state.

  19. Optical properties of Dy3+ doped bismuth zinc borate glass and glass ceramics

    NASA Astrophysics Data System (ADS)

    Shanmugavelu, B.; Kanth Kumar, V. V. Ravi

    2012-06-01

    Dy3+ doped bismuth zinc borate transparent glasses were prepared by melt quenching technique and these glasses were used precursor to obtain transparent glass ceramics by heat treatment method. XRD pattern of the glass ceramic shows the formation of the β-BiB3O6 and Bi2ZnOB2O6 phases. The visible emission intensity of the glass ceramics is stronger than the glass. This can be due to the formation of nano nonlinear optical crystallites in glass matrix.

  20. Optical transitions of Dy/sup 3 +/ ions in fluorozirconate glass

    SciTech Connect

    Adam, J.L.; Docq, A.D.; Lucas, J.

    1988-08-01

    Optical absorption and emission spectra are presented for Dy/sup 3 +/ ions in fluorozirconate (ZBLA) glass. The measured oscillator strengths and radiative rates for several transitions are compared with calculated values. Radiative transition rates for the excited states are determined by using the Judd-Ofelt theory (B.R. Judd, Phys. Rev. 127, 750 (1962); G.S. Ofelt, J. Chem. Phys. 37, 511 (1962)). Thermal evolution of the radiative rate is observed for the /sup 4/F/sub 9/2/ level and is well accounted for by Start level thermalization. Energy transfer effects are responsible for the nonradiative transitions.