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Sample records for 5posub 4sub 3f

  1. Solvothermal indium fluoride chemistry: Syntheses and crystal structures of K{sub 5}In{sub 3}F{sub 14}, beta-(NH{sub 4}){sub 3}InF{sub 6} and [NH{sub 4}]{sub 3}[C{sub 6}H{sub 21}N{sub 4}]{sub 2}[In{sub 4}F{sub 21}

    SciTech Connect

    Jayasundera, Anil C.A.; Goff, Richard J.; Li Yang; Finch, Adrian A.; Lightfoot, Philip

    2010-02-15

    The solvothermal syntheses and crystal structures of three indium fluorides are presented. K{sub 5}In{sub 3}F{sub 14} (1) and beta-(NH{sub 4}){sub 3}InF{sub 6} (2) are variants on known inorganic structure types chiolite and cryolite, respectively, with the latter exhibiting a complex and apparently novel structural distortion. [NH{sub 4}]{sub 3}[C{sub 6}H{sub 21}N{sub 4}]{sub 2}[In{sub 4}F{sub 21}] (3) represents a new hybrid composition displaying a unique trimeric metal fluoride building unit. - Graphical abstract: Solvothermal synthesis has been used to prepare three indium fluorides, including a novel hybrid material containing a unique [In{sub 3}F{sub 15}] trimer templated by tren.

  2. Mild hydrothermal synthesis, crystal structure, thermal behavior, spectroscopic and magnetic properties of the (NH{sub 4})[Fe(AsO{sub 4}){sub 1-x}(PO{sub 4}){sub x}F] (x=0.3, 0.6, 0.8) series. Thermal transformation of (NH{sub 4})[Fe(AsO{sub 4}){sub 0.7}(PO{sub 4}){sub 0.3}F] into the textural porous orthorhombic Fe(AsO{sub 4}){sub 0.7}(PO{sub 4}){sub 0.3}

    SciTech Connect

    Berrocal, Teresa

    2009-04-15

    The (NH{sub 4})[Fe(AsO{sub 4}){sub 1-x}(PO{sub 4}){sub x}F] (x=0.3, 0.6, 0.8) series of compounds has been synthesized under mild hydrothermal conditions. The compounds crystallize in the orthorhombic Pna2{sub 1} space group, with the unit-cell parameters a=13.1718(1), b=6.5966(6), c=10.797(1) A for x=0.3; a=13.081(1), b=6.5341(6), c=10.713(1) A for x=0.6 and a=13.0329(9), b=6.4994(4), c=10.6702(6) A for x=0.8, with the volumes 938.6(1), 915.7(1) and 903.8(1) A{sup 3}, respectively, with Z=8. Single crystals of (NH{sub 4})[Fe(AsO{sub 4}){sub 0.7}(PO{sub 4}){sub 0.3}F] heated under air atmosphere at 465 deg. C remain as single crystals, changing the composition to Fe(AsO{sub 4}){sub 0.7}(PO{sub 4}){sub 0.3}. This later phase belongs to the orthorhombic Imam space group, with the unit cell parameters a=13.328(2), b=6.5114(5), c=10.703(1) A, V=928.9(2) A{sup 3} and Z=12. The crystal structure of the ammonium phases consists of a KTP three-dimensional framework constructed by chains formed by alternating Fe(2)O{sub 4}F{sub 2} or Fe(1)O{sub 4}F{sub 2} octahedra and As/P(2)O{sub 4} or As/P(1)O{sub 4} tetrahedra, respectively. These octahedra and tetrahedra are linked by a common oxygen vertex. The chains run along the 'a' and 'b' crystallographic axes. The crystal structure of Fe(AsO{sub 4}){sub 0.7}(PO{sub 4}){sub 0.3} is a three-dimensional skeleton derived from that of the precursor, formed from (100) sheets stacked along the [001] direction, and interconnected by chains of alternating Fe(2)O{sub 6} octahedra and As/P(2)O{sub 4} tetrahedra sharing a vertex in the 'a' direction. Transmission electronic microscopy of this compound indicates the existence of unconnected external cavities with a BET surface area of 3.91(3) m{sup 2} g{sup -1}. The diffuse reflectance spectra in the visible region show the forbidden electronic transitions characteristic of the Fe(III) d{sup 5}-high spin cation in slightly distorted octahedral geometry, for all the compounds. The ESR spectra

  3. Investigation of structural and luminescent properties of Ce{sup 3+}/Mn{sup 2+} ions-doped Ca{sub 5}(PO{sub 4}){sub 3}F

    SciTech Connect

    Zhang, Lei; Fu, Zuoling; Wu, Zhijian; Wang, Yuan; Fu, Xihong; Cui, Tian

    2014-08-15

    Graphical abstract: The structural and luminescent properties FAP: Ce{sup 3+} and FAP: Ce{sup 3+}, Mn{sup 2+} were investigated in detail by the spectral measurement and theoretical calculation. The emission of Ce{sup 3+} is fitted by two Gaussian functions dashed lines in wavenumber to further confirm the Ce{sup 3+} ion simultaneously occupy the 4f and 6h sites Ca{sub 5}(PO{sub 4})F host. - Highlights: • A simple hydrothermal method has been used to prepare Ca{sub 5}(PO{sub 4}){sub 3}F: Ce{sup 3+}, Mn{sup 2+} powders with structural and luminescent analysis. • The emission of Ce{sup 3+} is fitted by two Gaussian functions to confirm the Ce{sup 3+} ion simultaneously to occupy the 4f and 6h sites in Ca{sub 5}(PO{sub 4}){sub 3}F host. • Due to an efficient energy transfer, the existence of Ce{sup 3+} (sensitizer) can dramatically enhance the green emission of Mn{sup 2+} (activator) in co-doped samples. - Abstract: Ce{sup 3+}/Mn{sup 2+} ions-doped oxyapatite calcium fluorapatite [Ca{sub 5}(PO{sub 4}){sub 3}F, FAP] has been successfully synthesized by a facile one-step hydrothermal method. The luminescent properties of Ce{sup 3+}- and Ce{sup 3+}/Mn{sup 2+}- activated FAP phosphors were investigated using the photoluminescence (PL) and photoluminescence excitation (PLE) spectra. The emission of Ce{sup 3+} was fitted by two Gaussian functions with dashed lines in wavenumber to confirm the Ce{sup 3+} ion simultaneously to occupy the 4f and 6h sites in Ca{sub 5}(PO{sub 4}){sub 3}F host, which was consistent with the calculated results of crystal field based on chemical bond theory. In addition, the existence of Ce{sup 3+} (sensitizer) can dramatically enhance the green emission of Mn{sup 2+} (activator) in Ce{sup 3+}/Mn{sup 2+} ions co-doped samples due to an efficient energy transfer from Ce{sup 3+} to Mn{sup 2+}. All of these results could help us understand the site assignments and optical properties of the rare earth ions doped in hexagonal Ca{sub 5}(PO{sub 4

  4. Influence of 6s{sup 2} lone pair electrons of Bi{sup 3+} on its preferential site occupancy in fluorapatite, NaCa{sub 3}Bi(PO{sub 4}){sub 3}F – An insight from Eu{sup 3+} luminescent probe

    SciTech Connect

    Lakshminarasimhan, N. Varadaraju, U.V.

    2014-12-15

    Graphical abstract: Eu{sup 3+} structural probe – difference in Eu{sup 3+} PL emission in (a) NaCa{sub 3}Bi{sub 0.95}Eu{sub 0.05}(PO{sub 4}){sub 3}F and (b) NaCa{sub 3}La{sub 0.95}Eu{sub 0.05}(PO{sub 4}){sub 3}F suggests Bi{sup 3+} with preferential site occupancy at M(II) site directing Eu{sup 3+} to M(I) site. - Highlights: • Eu{sup 3+} luminescent probe used for establishing the role of 6s{sup 2} lone pair electrons of Bi{sup 3+} in fluorapatite. • Difference in Eu{sup 3+} PL emission spectral features in NaCa{sub 3}Bi{sub 0.95}Eu{sub 0.05}(PO{sub 4}){sub 3}F and NaCa{sub 3}La{sub 0.95}Eu{sub 0.05}(PO{sub 4}){sub 3}F. • Preferential site occupancy of Bi{sup 3+} in M(II) site directs Eu{sup 3+} to M(I) site in NaCa{sub 3}Bi{sub 0.95}Eu{sub 0.05}(PO{sub 4}){sub 3}F. - Abstract: Eu{sup 3+} luminescence was used as a structural probe in understanding the preferential site occupancy of lone pair cation, Bi{sup 3+}, in fluorapatite by comparing the photoluminescence (PL) emission spectral features with that of in analogous La{sup 3+} based fluorapatite. The fluorapatites, NaCa{sub 3}Bi{sub 0.95}Eu{sub 0.05}(PO{sub 4}){sub 3}F and NaCa{sub 3}La{sub 0.95}Eu{sub 0.05}(PO{sub 4}){sub 3}F, were synthesized by conventional high temperature solid state reaction method and characterized by powder X-ray diffraction (XRD) and FT-IR spectroscopy. The Eu{sup 3+} PL results revealed a difference in the emission spectral features in NaCa{sub 3}Bi{sub 0.95}Eu{sub 0.05}(PO{sub 4}){sub 3}F and NaCa{sub 3}La{sub 0.95}Eu{sub 0.05}(PO{sub 4}){sub 3}F. This difference in Eu{sup 3+} PL emission can be attributed to the difference in its site occupancy in the studied fluorapatites.

  5. Electron Interactions With C3F8

    NASA Astrophysics Data System (ADS)

    Christophorou, L. G.; Olthoff, J. K.

    1998-09-01

    To aid the many and diverse applications for which perfluoropropane (C3F8) is suited, we critically evaluate and synthesize existing knowledge on electron scattering and electron energy-loss processes for the C3F8 molecule, and provide recommendations for the most reliable data. We also draw attention to electron-interaction data that are not presently available, but are needed for modeling the behavior of C3F8 in practical uses, especially plasma processing.

  6. Thermodynamic Model for the Solubility of Ba(SeO4sub>, SO4sub>) Precipitates

    SciTech Connect

    Rai, D.; Felmy, Andrew R.; Moore, Dean A.; Kitamura, Akira; Yoshikawa, Hideki; Doi, Reisuke; Yoshida, Yasushi

    2014-08-15

    The solubility of Ba(SeO4sub>, SO4sub>) precipitates was determined as a function of the BaSeO4sub> mole fractions, ranging from 0.0015 to 0.3830, and time with an equilibration period extending to as long as 302 days. Equilibrium/steady state conditions in this system are reached in ≤ 65 days. Pitzer’s ion interaction model was used to calculate solid and aqueous phase activity coefficients. Thermodynamic analyses showed that the data do not satisfy Gibbs-Duhem equation, thereby demonstrating that a single-solid solution phase does not control both the selenate and sulfate concentrations. Our extensive data with log 10 [Ba] ranging from -3.6 to -5.9 mol kg-1, log 10 [SeO4sub>] rangingfrom-3.6 to -5.2 mol kg-1, and log 10 [SO4sub>] ranging from-4.0 to -5.3 mol kg-1 can be explained with the formation of an ideal BaSeO4sub> solid solution phase that controls the selenium concentrations and a slightly disordered/less-crystalline BaSO4sub>(s) (log 10Κ°sp = -9.5 instead of -10.05 for barite) that controls the sulfate concentrations. In these experiments the BaSO4sub> component of the solid solution phase never reaches thermodynamic equilibrium with the aqueous phase. Thermodynamic interpretations of the data show that both the ideal BaSeO4sub> solid solution phase and less-crystalline BaSO4sub> (s) phase are in equilibrium with each other in the entire range of BaSeO4sub> mole fractions investigated in this study.

  7. Near Infrared Luminescence Properties of Mn(5+): Ca5(PO4)3F

    NASA Technical Reports Server (NTRS)

    Davis, Valetta R.; Hoemmerich, Uwe; Loutts, George B.

    1997-01-01

    We report a spectroscopic investigation of Mn(5+) doped Ca5(PO4)(sub 3)F or FAP. Mn(5+) doped crystals have recently attracted world wide attention for potential solid-state laser applications. Following optical excitation of Mn: FAP with the 600 nm output of a Nd: YAG OPO laser system, we observed a strong near infrared luminescence centered at around 1150 nm. The room temperature luminescence decay time was measured to be approximately 635 microseconds. We attribute the infrared luminescence to the(1)E yields (3)A2 transition of tetrahedrally coordinated Mn5+ ions located in a strong crystal field environment. Absorption, luminescence and lifetime data of Mn: FAP will be presented and discussed.

  8. Solvate Structures and Computational/Spectroscopic Characterization of LiBF4sub> Electrolytes

    SciTech Connect

    Seo, D. M.; Boyle, Paul D.; Allen, Joshua L.; Han, Sang D.; Jonsson, Erlendur; Johansson, Patrik; Henderson, Wesley A.

    2014-07-21

    Crystal structures have been determined for both LiBF4sub> and HBF4sub> solvates—(acetonitrile)2:LiBF4sub>, (ethylene glycol diethyl ether)1:LiBF4sub>, (diethylene glycol diethyl ether)1:LiBF4sub>, (tetrahydrofuran)1:LiBF4, (methyl methoxyacetate)1:LiBF4sub>, (suc-cinonitrile)1:LiBF4sub>, (N,N,N',N",N"-pentamethyldiethylenetriamine)1:HBF4sub>, (N,N,N',N'-tetramethylethylenediamine)3/2:HBF4sub> and (phenanthroline)2:HBF4sub>. These, as well as other known LiBF4sub> solvate structures, have been characterized by Raman vibrational spectroscopy to unambiguously assign the anion Raman band positions to specific forms of BF4sub>-...Li+ cation coordination. In addition, complementary DFT calculations of BF4sub>-...Li+ cation complexes have provided additional insight into the challenges associated with accurately interpreting the anion interactions from experimental Raman spectra. This information provides a crucial tool for the characterization of the ionic association interactions within electrolytes.

  9. Structural study of the ammonium octafluoroneptunate, [NH4sub>]4sub>NpF8

    SciTech Connect

    Poineau, Frederic; Silva, Chinthaka M.; Yeamans, Charles B.; Cerefice, Gary S.; Sattelberger, Alfred P.; Czerwinski, Kenneth R.

    2016-07-01

    The [NH4sub>]4sub>NpF8 salt was prepared from the solid-state reaction of NpO2 with NH4sub>HF2 and characterized by powder X-ray diffraction and X-ray absorption fine structure spectroscopy. The diffraction results confirm the compound to be isostructural to [NH4sub>]4sub>UF8 with the following lattice parameter (a = 13.054(4) Å, b = 6.681(2) Å, c = 13.676(5) Å, ß = 121.14 Å). For the first time, a Neptunium fluoride complex has been characterized by XAFS spectroscopy. The energy position of the white line and inflection of the XANES spectra of [NH4sub>]4sub>NpF8 are consistent with the presence of Np(IV). Adjustment of the EXAFS spectra indicates that the coordination number (7.4±1.5) and the average Np-F distance (2.26(1) Å) are consistent with the presence of the NpF8 dodecahedron. The average Np-F distance is ~0.02 Å shorter than the U-F distance in [NH4sub>]4sub>UF8 and is a result of the actinide contraction.

  10. Hybridization gap in the semiconducting compound SrIr4sub>In2Ge4sub>

    SciTech Connect

    Calta, Nicholas P.; Im, Jino; Fang, Lei; Chasapis, Thomas C.; Bugaris, Daniel E.; Chung, Duck Young; Kwok, Wai -Kwong; Kanatzidis, Mercouri G.

    2016-11-18

    Here, large single crystals of SrIr4sub>In2Ge4sub> were synthesized using the In flux method. This compound is a hybridization gap semiconductor with an experimental optical band gap of Eg = 0.25(3) eV. It crystallizes in the tetragonal EuIr4sub>In2Ge4sub> structure type with space group 1$\\overline{4}$2m and unit cell parameters a = 6.9004(5) Å and c = 8.7120(9) Å. The electronic structure is very similar to both EuIr4sub>In2Ge4sub> and the parent structure Ca3Ir4sub>Ge4sub>, suggesting that these compounds comprise a new family of hybridization gap materials that exhibit indirect gap, semiconducting behavior at a valence electron count of 60 per formula unit, similar to the Heusler alloys.

  11. Dirac node arcs in PtSn4sub>

    SciTech Connect

    Wu, Yun; Wang, Lin -Lin; Mun, Eundeok; Johnson, D. D.; Mou, Daixiang; Huang, Lunan; Lee, Yongbin; Bud’ko, S. L.; Canfield, P. C.; Kaminski, Adam

    2016-04-04

    In topological quantum materials1,2,3 the conduction and valence bands are connected at points or along lines in the momentum space. A number of studies have demonstrated that several materials are indeed Dirac/Weyl semimetals4,5,6,7,8. However, there is still no experimental confirmation of materials with line nodes, in which the Dirac nodes form closed loops in the momentum space2,3. Here we report the discovery of a novel topological structure—Dirac node arcs—in the ultrahigh magnetoresistive material PtSn4sub> using laser-based angle-resolved photoemission spectroscopy data and density functional theory calculations. Unlike the closed loops of line nodes, the Dirac node arc structure arises owing to the surface states and resembles the Dirac dispersion in graphene that is extended along a short line in the momentum space. Here, we propose that this reported Dirac node arc structure is a novel topological state that provides an exciting platform for studying the exotic properties of Dirac fermions.

  12. The translation initiation factor 3f (eIF3f) exhibits a deubiquitinase activity regulating Notch activation.

    PubMed

    Moretti, Julien; Chastagner, Patricia; Gastaldello, Stefano; Heuss, Sara F; Dirac, Annette M; Bernards, René; Masucci, Maria G; Israël, Alain; Brou, Christel

    2010-11-23

    Activation of the mammalian Notch receptor after ligand binding relies on a succession of events including metalloprotease-cleavage, endocytosis, monoubiquitination, and eventually processing by the gamma-secretase, giving rise to a soluble, transcriptionally active molecule. The Notch1 receptor was proposed to be monoubiquitinated before its gamma-secretase cleavage; the targeted lysine has been localized to its submembrane domain. Investigating how this step might be regulated by a deubiquitinase (DUB) activity will provide new insight for understanding Notch receptor activation and downstream signaling. An immunofluorescence-based screening of an shRNA library allowed us to identify eIF3f, previously known as one of the subunits of the translation initiation factor eIF3, as a DUB targeting the activated Notch receptor. We show that eIF3f has an intrinsic DUB activity. Knocking down eIF3f leads to an accumulation of monoubiquitinated forms of activated Notch, an effect counteracted by murine WT eIF3f but not by a catalytically inactive mutant. We also show that eIF3f is recruited to activated Notch on endocytic vesicles by the putative E3 ubiquitin ligase Deltex1, which serves as a bridging factor. Finally, catalytically inactive forms of eIF3f as well as shRNAs targeting eIF3f repress Notch activation in a coculture assay, showing that eIF3f is a new positive regulator of the Notch pathway. Our results support two new and provocative conclusions: (1) The activated form of Notch needs to be deubiquitinated before being processed by the gamma-secretase activity and entering the nucleus, where it fulfills its transcriptional function. (2) The enzyme accounting for this deubiquitinase activity is eIF3f, known so far as a translation initiation factor. These data improve our knowledge of Notch signaling but also open new avenues of research on the Zomes family and the translation initiation factors.

  13. Molecular and electronic structure of Re2Br4sub>(PMe3)4sub>

    SciTech Connect

    Johnstone, Erik V.; Poineau, Frederic; Todorova, Tanya K.; Forster, Paul M.; Sorensen, Lasse K.; Fdez. Galvan, Ignacio; Lindh, Roland; Czerwinski, Kenneth R.; Sattelberger, Alfred P.

    2016-07-07

    The dinuclear rhenium(II) complex Re2Br4sub>(PMe3)4sub> was prepared from the reduction of [Re2Br8]2– with (n-Bu4sub>N)BH4sub> in the presence of PMe3 in propanol. The complex was characterized by single-crystal X-ray diffraction (SCXRD) and UV–visible spectroscopy. It crystallizes in the monoclinic C2/c space group and is isostructural with its molybdenum and technetium analogues. The Re–Re distance (2.2521(3) Å) is slightly longer than the one in Re2Cl4sub>(PMe3)4sub> (2.247(1) Å). The molecular and electronic structure of Re2X4sub>(PMe3)4sub> (X = Cl, Br) were studied by multiconfigurational quantum chemical methods. The computed ground-state geometry is in excellent agreement with the experimental structure determined by SCXRD. The calculated total bond order (2.75) is consistent with the presence of an electron-rich triple bond and is similar to the one found for Re2Cl4sub>(PMe3)4sub>. The electronic absorption spectrum of Re2Br4sub>(PMe3)4sub> was recorded in benzene and shows a series of low-intensity bands in the range 10 000–26 000 cm–1. The absorption bands were assigned based on calculations of the excitation energies with the multireference wave functions followed by second-order perturbation theory using the CASSCF/CASPT2 method. As a result, calculations predict that the lowest energy band corresponds to the δ* → σ* transition, while the next higher energy bands were attributed to the δ* → π*, δ → σ*, and δ → π* transitions.

  14. Solution-processable glass LiI-Li4sub>SnS4sub> superionic conductors for all-solid-state Li-ion batteries

    SciTech Connect

    Kern Ho Park; Oh, Dae Yang; Choi, Young Eun; Nam, Young Jin; Han, Lili; Kim, Ju -Young; Xin, Huolin; Lin, Feng; Oh, Seung M.; Jung, Yoon Seok

    2015-12-22

    The new, highly conductive (4.1 × 10–4 S cm–1 at 30 °C), highly deformable, and dry-air-stable glass 0.4LiI-0.6Li4sub>SnS4sub> is prepared using a homogeneous methanol solution. Furthermore, the solution process enables the wetting of any exposed surface of the active materials with highly conductive solidified electrolytes (0.4LiI-0.6Li4sub>SnS4sub>), resulting in considerable improvements in electrochemical performances of these electrodes over conventional mixture electrodes.

  15. U(v) in Metal Uranates. A Combined Experimental And Theoretical Study of MgUO4sub>, CrUO4sub> and FeUO4sub>

    SciTech Connect

    Guo, Xiaofeng; Tiferet, Eitan; Qi, Liang; Solomon, J.; Lanzirotti, Anthony; Newville, Mathew; Engelhard, Mark H.; Kukkadapu, Ravi K.; Wu, Di; Ilton, Eugene S.; Asta, Mark D.; Sutton, Steve; Xu, Hongwu; Navrotsky, Alexandra

    2016-02-02

    Pentavalent uranium can exist in aqueous solution, but its presence in the solid state is uncommon. Metal monouranates, MgUO4sub>, CrUO4sub> and FeUO4sub> were synthesized for detailed structural and energetic investigations. Structural characteristics of these uranates used powder X-ray diffraction, synchrotron X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, and 57Fe-Mössbauer spectroscopy. Enthalpies of formation were measured by high temperature oxide melt solution calorimetry. Density functional theory (DFT) calculations provided both structural and energetic information. The measured structural and thermodynamic properties show good consistency with those predicted from DFT. Moreover, the presence of U5+ has been solidly confirmed in CrUO4sub> and FeUO4sub>, which are thermodynamically stable compounds, and the origin and stability of U5+ in the system was elaborated by DFT. The structural and thermodynamic behaviour of U5+ elucidated in this work is relevant to fundamental actinide redox chemistry and to applications in the nuclear industry and radioactive waste disposal.

  16. U(v) in metal uranates: A combined experimental and theoretical study of MgUO4sub>, CrUO4sub>, and FeUO4sub>

    SciTech Connect

    Guo, Xiaofeng; Tiferet, Eitan; Qi, Liang; Solomon, Jonathan M.; Lanzirotti, Antonio; Newville, Matthew; Engelhard, Mark H.; Kukkadapu, Ravi K.; Wu, Di; Ilton, Eugene S.; Asta, Mark; Sutton, Stephen R.; Xu, Hongwu; Navrotsky, Alexandra

    2016-01-01

    Although pentavalent uranium can exist in aqueous solution, its presence in the solid state is uncommon. Metal monouranates, MgUO4sub>, CrUO4sub> and FeUO4sub> were synthesized for detailed structural and energetic investigations. Structural characteristics of these uranates used powder X-ray diffraction, synchrotron X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, and 57Fe-Mossbauer spectroscopy. Enthalpies of formation were measured by high temperature oxide melt solution calorimetry. Density functional theory (DFT) calculations provided both structural and energetic information. The measured structural and thermodynamic properties show good consistency with those predicted from DFT. The presence of U5+ has been solidly confirmed in CrUO4sub> and FeUO4sub>, which are thermodynamically stable compounds, and the origin and stability of U5+ in the system was elaborated by DFT. Lastly, the structural and thermodynamic behaviour of U5+ elucidated in this work is relevant to fundamental actinide redox chemistry and to applications in the nuclear industry and radioactive waste disposal.

  17. Partial discharges and breakdown in C3F8

    NASA Astrophysics Data System (ADS)

    Koch, M.; Franck, C. M.

    2014-10-01

    Traditional search processes of gases or gas mixtures for replacing SF6 involve time consuming measurements of partial discharges and breakdown behaviour for several voltage waveforms and different field configurations. Recently a model for prediction of this behaviour for SF6 was described in literature. The model only requires basic properties of the gas such as the critical field strength and the effective ionization coefficient, which can be obtained by swarm parameter measurements, and thermodynamic properties, which can be calculated. In this paper, we show for the well-known and electronegative gas octafluoropropane (C3F8) that it is possible to transfer the model developed for SF6 to this gas to describe the breakdown behaviour of C3F8. Thus the model can be beneficial in the screening process of new insulation gases.

  18. Near-infrared quantum-cutting luminescence and energy transfer properties of Ca{sub 3}(PO{sub 4}){sub 2}:Tm{sup 3+},Ce{sup 3+} phosphors

    SciTech Connect

    Dong, S. L.; Lin, H. H. E-mail: qyzhang@scut.edu.cn; Yu, T.; Zhang, Q. Y. E-mail: qyzhang@scut.edu.cn

    2014-07-14

    The phosphors Ca{sub 3}(PO{sub 4}){sub 2}:Tm{sup 3+} by co-doping Ce{sup 3+} have been synthesized by conventional high-temperature solid-state reaction method. Their spectroscopic properties in the UV-VIS-NIR range have been investigated. The first 5d crystal field level location and stokes shift have been determined from the UV excitation and emission spectra of Ca{sub 3}(PO{sub 4}){sub 2}:Ce{sup 3+}. The three-photon NIR quantum-cutting luminescence of Tm{sup 3+} assigned to the electronic transitions of {sup 1}G{sub 4}→{sup 3}H{sub 4}, {sup 3}H{sub 4}→{sup 3}F{sub 4} and {sup 3}F{sub 4}→{sup 3}H{sub 6} is observed, whether in Ca{sub 3}(PO{sub 4}){sub 2}:Tm{sup 3+} or Ca{sub 3}(PO{sub 4}){sub 2}:Tm{sup 3+},Ce{sup 3+}. The energy transfer from Ce{sup 3+} to Tm{sup 3+} takes place with energy-transfer efficiency up to 34.5% for the Ca{sub 3}(PO{sub 4}){sub 2}:Tm{sup 3+},Ce{sup 3+}. A cross relaxation scheme using the 5d states of Ce{sup 3+} and f-f transition of Tm{sup 3+} is proposed. The mechanism is revealed from energy level and decay measurements. The results show that the broadband absorption of Ce{sup 3+} sensitizer not only extends the spectrum conversion in UV region but also greatly enhances the photoluminescence intensities of the three-photon quantum cutting luminescence of Tm{sup 3+} doped Ca{sub 3}(PO{sub 4}){sub 2}.

  19. ABET Criterion 3.f: how much curriculum content is enough?

    PubMed

    Barry, B E; Ohland, M W

    2012-06-01

    Even after multiple cycles of ABET accreditation, many engineering programs are unsure of how much curriculum content is needed to meet the requirements of ABET's Criterion 3.f (an understanding of professional and ethical responsibility). This study represents the first scholarly attempt to assess the impact of curriculum reform following the introduction of ABET Criterion 3.f. This study sought to determine how much professional and ethical responsibility curriculum content was used between 1995 and 2005, as well as how, when, why, and to what effect changes in the amount of content occurred. Subsequently, the study sought to evaluate if different amounts of curriculum content generated differing student outcomes. The amount of curriculum content used by each of the participating programs was identified during semi-structured interviews with program administrators and a review of ABET Self-Study documents. Quantitative methods were applied to determine if a relationship existed between the curriculum content and performance on a nationally administered, engineering-specific standardized examination. The findings indicate a statistical relationship, but a lack of structure between the amount of required content in the curriculum and performance on the examination. Additional findings were also generated regarding the way that programs interpret the Criterion 3.f feedback generated during accreditation visits. The primary impact of this study is that it dispels the myth that more courses or course time on professionalism and ethics will necessarily lead to positive engineering education outcomes. Much of the impetus to add more curriculum content results from a lack of conclusive feedback during ABET accreditation visits.

  20. Investigation of dielectric properties of cold C3F8 mixtures and hot C3F8 gas as Substitutes for SF6

    NASA Astrophysics Data System (ADS)

    Wang, Xiaohua; Zhong, Linlin; Yan, Jing; Yang, Aijun; Han, Guohui; Han, Guiquan; Wu, Yi; Rong, Mingzhe

    2015-10-01

    In order to reduce the global warming potential resulting from SF6 widely used as an insulating and arc quenching medium, the substitutes need to be found. This paper focuses on different cold C3F8 mixtures (at room temperature) as an insulating gas and hot C3F8 gas (at temperatures of 300-3500 K) as an arc quenching medium, which seem to be a good replacement of SF6. Firstly, the dielectric properties, including the reduced ionization coefficient α / N, reduced electron attachment coefficient η / N and reduced critical electric field strength ( E / N)cr, of the cold C3F8-CF4, C3F8-CO2, C3F8-N2, C3F8-O2 and C3F8-Ar mixtures are calculated numerically using the two-term approximation of the Boltzmann equation. The dependence of such dielectric properties on the buffer gas proportion is investigated. Among the various C3F8 mixtures, the C3F8-N2 mixture has the lowest α / N and the C3F8-CF4 mixture has the largest η / N, and moreover, the C3F8-N2 mixture is the best insulator in terms of breakdown strength because it has the largest ( E / N)cr. Secondly, the ( E / N)cr of hot C3F8 at temperatures up to 3500 K and various pressures is determined and compared with that of hot SF6 gas. It is found that the hot C3F8 gas has much poorer dielectric performance than hot SF6 because the ( E / N)cr of C3F8 decreases significantly above room temperature.

  1. Characterization of uranium tetrafluoride (UF4sub>) with Raman spectroscopy

    SciTech Connect

    Villa-Aleman, Eliel; Wellons, Matthew S.

    2016-03-22

    The Raman spectrum of uranium tetrafluoride (UF4sub>) is unambiguously characterized with multiple Raman excitation laser sources for the first time. Across different laser excitation wavelengths, UF4sub> demonstrates 16 distinct Raman bands within the 50-400 cm-1 region. The observed Raman bands are representative of various F-F vibrational modes. UF4sub> also shows intense fluorescent bands in the 325 – 750 nm spectral region. Comparison of the UF4sub> spectrum with the ZrF4sub> spectrum, its crystalline analog, demonstrates a similar Raman band structure consistent with group theory predictions for expected Raman bands. Additionally, a demonstration of combined scanning electron microscopy (SEM) and in situ Raman spectroscopy microanalytical measurements of UF4 sub>particulates shows that despite the inherent weak intensity of Raman bands, identification and characterization are possible for micron-sized particulates with modern instrumentation. The published well characterized UF4sub> spectrum is extremely relevant to nuclear materials and nuclear safeguard applications.

  2. Revealing the Restructured Surface of Li[Mn2]O4sub>

    SciTech Connect

    Amos, Charles D.; Roldan, Manuel A.; Varela, Maria; Goodenough, John B.; Ferreira, Paulo J.

    2016-03-29

    The spinel Revealing the Restructured Surface of Li[Mn2]O4sub> is a candidate cathode for a Li-ion battery, but its capacity fades over a charge/discharge cycle of Li1–x[Mn2]O4sub> (0 < x < 1) that is associated with a loss of Mn to the organic-liquid electrolyte. It is known that the disproportionation reaction 2Mn3+ = Mn2+ + Mn4+ occurs at the surface of a Mn spinel, and it is important to understand the atomic structure and composition of the surface of Revealing the Restructured Surface of Li[Mn2]O4sub> in order to understand how Mn loss occurs. We report a study of the surface reconstruction of Revealing the Restructured Surface of Li[Mn2]O4sub> by aberration-corrected scanning transmission electron microscopy. The atomic structure coupled with Mn-valence and the distribution of the atomic ratio of oxygen obtained by electron energy loss spectroscopy reveals a thin, stable surface layer of Mn3O4sub>, a subsurface region of Li1+x[Mn2]O4sub> with retention of bulk Li[Mn2]O4sub>. We conclude that this observation is compatible with the disproportionation reaction coupled with oxygen deficiency and a displacement of surface Li+ from the Mn3O4sub> surface phase. These results provide a critical step toward understanding how Mn is lost from Li[Mn2]O4sub>, once inside a battery.

  3. Synthesis of silicated hydroxyapatite Ca{sub 10}(PO{sub 4}){sub 6-x}(SiO{sub 4}){sub x}(OH){sub 2-x}

    SciTech Connect

    Palard, Mickael; Champion, Eric Foucaud, Sylvie

    2008-08-15

    The preparation of silicated hydroxyapatite Ca{sub 10}(PO{sub 4}){sub 6-x}(SiO{sub 4}){sub x}(OH){sub 2-x} (SiHA) with 0{<=}x{<=}2 was investigated using a wet precipitation method followed by a heat treatment. X-ray diffraction and Rietveld refinement, Fourier transformed IR (FTIR) spectroscopy, elemental analyses, transmission electron microscopy and thermal analyses were used to characterize the samples. The raw materials were composed of a partially silicated and carbonated apatite and a secondary minor phase containing the excess silicon. Single phase silicated hydroxyapatites, with 0{<=}x{<=}1, could be synthesized after a thermal treatment of the raw powders above 700 deg. C. The presence of carbonate groups in the raw apatite played an important role in the incorporation of silicates during heating. From the different results, the mechanisms of formation of SiHA are discussed. - Graphical abstract: The preparation of pure silicated hydroxyapatite Ca{sub 10}(PO{sub 4}){sub 6-x}(SiO{sub 4}){sub x}(OH){sub 2-x} powders with controlled silicon content was investigated. The synthesis route included a precipitation in aqueous media. It required an additional high temperature solid-state reaction to fully incorporate the silicon into the apatite crystals.

  4. Aqueous Sulfate Separation by Sequestration of [(SO4sub>)2(H2O)4sub>]4sub> Clusters within Highly Insoluble Imine-Linked Bis-Guanidinium Crystals

    SciTech Connect

    Custelcean, Radu; Williams, Neil J.; Seipp, Charles A.; Ivanov, Aleksandr; Bryantsev, Vyacheslav

    2015-12-18

    Quantitative removal of sulfate from seawater was achieved by selective crystallization of the anion with a bis(guanidinium) ligand self-assembled in situ through imine condensation of simple components. The resulting crystalline salt has an exceptionally low aqueous solubility, on a par with BaSO4sub>. Single-crystal X-ray diffraction analysis revealed pairs of sulfate anions clustered together with four water molecules within the crystals.

  5. Native defects in Tl6SI4sub>: Density functional calculations

    SciTech Connect

    Shi, Hongliang; Du, Mao -Hua

    2015-05-05

    In this study, Tl6SI4sub> is a promising room-temperature semiconductor radiation detection material. Here, we report density functional calculations of native defects and dielectric properties of Tl6SI4sub>. Formation energies and defect levels of native point defects and defect complexes are calculated. Donor-acceptor defect complexes are shown to be abundant in Tl6SI4sub>. High resistivity can be obtained by Fermi level pinning by native donor and acceptor defects. Deep donors that are detrimental to electron transport are identified and methods to mitigate such problem are discussed. Furthermore, we show that mixed ionic-covalent character of Tl6SI4sub> gives rise to enhanced Born effective charges and large static dielectric constant, which provides effective screening of charged defects and impurities.

  6. Origin of modulated phases and magnetic hysteresis in TmB4sub>

    SciTech Connect

    Wierschem, Keola; Sunku, Sai Swaroop; Kong, Tai; Ito, Toshimitsu; Canfield, Paul C.; Panagopoulos, Christos; Sengupta, Pinaki

    2015-12-23

    In this study, we investigate the low-temperature magnetic phases in TmB4sub>, a metallic quantum magnet on the geometrically frustrated Shastry-Sutherland lattice, using coordinated experimental and theoretical studies. Our results provide an explanation for the appearance of the intriguing fractional plateau in TmB4sub> and accompanying magnetic hysteresis. Together with observation of the bump in the half plateau, our results support the picture that the magnetization plateau structure in TmB4sub> is strongly influenced by the zero-field modulated phases. We present a phenomenological model to explain the appearance of the modulated phases and a microscopic Hamiltonian that captures the complete magnetic behavior of TmB4sub>.

  7. The hydrogen permeability of Pd4sub>S

    SciTech Connect

    O’Brien, Casey P.; Gellman, Andrew J.; Morreale, Bryan D.; Miller, James B.

    2011-04-01

    Hydrogen permeates rapidly through pure Pd membranes, but H2S, a common minor component in hydrogencontaining streams, produces a Pd4sub>S film on the Pd surface that severely retards hydrogen permeation. Hydrogen still permeates through the bi-layered Pd4sub>S/Pd structure, indicating that the Pd4sub>S surface is active for H2 dissociation; the low hydrogen permeability of the Pd4sub>S film is responsible for the decreased rate of hydrogen transport. In this work, the hydrogen permeability of Pd4sub>S was determined experimentally in the 623-773 K temperature range. Bi-layered Pd4sub>S/Pd foils were produced by exposing pure Pd foils to H2S. H2 fluxes through the bi-layered Pd4sub>S/Pd foils were measured during exposure to both pure H2 and a 1000 ppm H2S in H2 gas mixture. Our results show that H2S slows hydrogen permeation through Pd mainly by producing a Pd4S film on the Pd surface that is roughly an order-of-magnitude less permeable to hydrogen (kPd4S = 10-7.5 exp(-0.22 eV/kBT)molH2/m/s/Pa-1/2) than pure Pd. The presence of H2S in the gas stream results in greater inhibition of hydrogen transport than can be explained by the very low permeability of Pd4sub>S. H2S may block H2 dissociation sites at the Pd4sub>S surface.

  8. The role of carbonic anhydrase in C4sub> photosynthesis

    SciTech Connect

    Studer, Anthony

    2015-10-01

    Current pressures on the global food supply have accelerated the urgency for a second green revolution using novel and sustainable approaches to increase crop yield and efficiency. This proposal outlines experiments to address fundamental questions regarding the biology of C4sub> photosynthesis, the method of carbon fixation utilized by the most productive food, feed and bioenergy crops. Carbonic anhydrase (CA) has been implicated in multiple cellular functions including nitrogen metabolism, water use efficiency, and photosynthesis. CA catalyzes the first dedicated step in C4sub> photosynthesis, the hydration of CO2 into bicarbonate, and is potentially rate limiting in C4sub> grasses. Using insertional mutagenesis, we have generated CA mutants in maize, and propose the characterization of these mutants using phenotypic, physiological, and transcriptomic profiling to assay the plant’s response to altered CA activity. In addition, florescent protein tagging experiments will be employed to study the subcellular localization of CA paralogs, providing critical data for modeling carbon fixation in C4sub> plants. Finally, I propose parallel experiments in Setaria viridis to explore its relevance as model C4sub> grass. Using a multifaceted approach, this proposal addresses important questions in basic biology, as well as the need for translation research in response to looming global food challenges.

  9. Role of Acentric Displacements on the Crystal Structure and Second-Harmonic Generating Properties of RbPbCO3F and CsPbCO3F

    PubMed Central

    2015-01-01

    Two lead fluorocarbonates, RbPbCO3F and CsPbCO3F, were synthesized and characterized. The materials were synthesized through solvothermal and conventional solid-state techniques. RbPbCO3F and CsPbCO3F were structurally characterized by single-crystal X-ray diffraction and exhibit three-dimensional (3D) crystal structures consisting of corner-shared PbO6F2 polyhedra. For RbPbCO3F, infrared and ultraviolet–visible spectroscopy and thermogravimetric and differential thermal analysis measurements were performed. RbPbCO3F is a new noncentrosymmetric material and crystallizes in the achiral and nonpolar space group P6̅m2 (crystal class 6̅m2). Powder second-harmonic generation (SHG) measurements on RbPbCO3F and CsPbCO3F using 1064 nm radiation revealed an SHG efficiency of approximately 250 and 300 × α-SiO2, respectively. Charge constants d33 of approximately 72 and 94 pm/V were obtained for RbPbCO3F and CsPbCO3F, respectively, through converse piezoelectric measurements. Electronic structure calculations indicate that the nonlinear optical response originates from the distorted PbO6F2 polyhedra, because of the even–odd parity mixing of the O 2p states with the nearly spherically symmetric 6s electrons of Pb2+. The degree of inversion symmetry breaking is quantified using a mode-polarization vector analysis and is correlated with cation size mismatch, from which it is possible to deduce the acentric properties of 3D alkali-metal fluorocarbonates. PMID:24867361

  10. Role of acentric displacements on the crystal structure and second-harmonic generating properties of RbPbCO3F and CsPbCO3F.

    PubMed

    Tran, T Thao; Halasyamani, P Shiv; Rondinelli, James M

    2014-06-16

    Two lead fluorocarbonates, RbPbCO3F and CsPbCO3F, were synthesized and characterized. The materials were synthesized through solvothermal and conventional solid-state techniques. RbPbCO3F and CsPbCO3F were structurally characterized by single-crystal X-ray diffraction and exhibit three-dimensional (3D) crystal structures consisting of corner-shared PbO6F2 polyhedra. For RbPbCO3F, infrared and ultraviolet-visible spectroscopy and thermogravimetric and differential thermal analysis measurements were performed. RbPbCO3F is a new noncentrosymmetric material and crystallizes in the achiral and nonpolar space group P6m2 (crystal class 6m2). Powder second-harmonic generation (SHG) measurements on RbPbCO3F and CsPbCO3F using 1064 nm radiation revealed an SHG efficiency of approximately 250 and 300 × α-SiO2, respectively. Charge constants d33 of approximately 72 and 94 pm/V were obtained for RbPbCO3F and CsPbCO3F, respectively, through converse piezoelectric measurements. Electronic structure calculations indicate that the nonlinear optical response originates from the distorted PbO6F2 polyhedra, because of the even-odd parity mixing of the O 2p states with the nearly spherically symmetric 6s electrons of Pb(2+). The degree of inversion symmetry breaking is quantified using a mode-polarization vector analysis and is correlated with cation size mismatch, from which it is possible to deduce the acentric properties of 3D alkali-metal fluorocarbonates.

  11. Electrochemical and Solid-State Lithiation of Graphitic C 3 N 4sub>

    SciTech Connect

    Veith, Gabriel M.; Baggetto, Loïc; Adamczyk, Leslie A.; Guo, Bingkun; Brown, Suree S.; Sun, Xiao-Guang; Albert, Austin A.; Humble, James R.; Barnes, Craig E.; Bojdys, Michael J.; Dai, Sheng; Dudney, Nancy J.

    2013-02-12

    : Lithiated graphitic carbon n.itride (C3N4sub> ) was fabricated by electrochemical and solid-state reactions. The addition of Li to C3N4sub> results in a reaction between the Li and the graphite-like C3N species in C3N4sub>. This irreversible reaction leads to the formation of Li-CH=NR and Li-N=CR2 species, which are detrimental to anode properties. Suitable nitrogen-doped carbon structures for anode applications are predicted to need high concentrations of pyridinic C-N-C terminal bonds and low concentrations of w quaternary C3N species to boost electronic conductivity and reversibly cycle Li ions.

  12. Integrated Data Collection Analysis (IDCA) Program - KClO4sub>/Aluminum Mixture

    SciTech Connect

    Sandstrom, Mary M.; Brown, Geoffrey W.; Preston, Daniel N.; Pollard, Colin J.; Warner, Kirstin F.; Sorensen, Daniel N.; Remmers, Daniel L.; Whinnery, LeRoy L.; Shelley, Timothy J.; Reyes, Jose A.; Hsu, Peter C.; Reynolds, John G.

    2012-01-17

    The Integrated Data Collection Analysis (IDCA) program is conducting a Proficiency Test for Small-Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of a mixture of KClO4sub> and aluminum—KClO4sub>/Al mixture. This material was selected because of the challenge of performing SSST testing of a mixture of two solids. The mixture was found to be: 1) much less sensitive to impact than RDX, (LLNL being the exception) and PETN, 2) more sensitive to friction than RDX and PETN, and 3) extremely sensitive to spark. The thermal analysis showed little or no exothermic character. One prominent endothermic feature was observed in the temperature range studied and identified as a phase transition of KClO4sub>.

  13. Two-micron lasing in NaLa{sub 1/2}Gd{sub 1/2}(WO{sub 4}){sub 2} crystals doped with Tm{sup 3+} ions

    SciTech Connect

    Bolshchikov, F A; Ryabochkina, P A; Zharikov, Evgeny V; Lis, Denis A; Subbotin, Kirill A; Zakharov, N G; Antipov, Oleg L

    2010-02-28

    Lasing on the {sup 3}F{sub 4{yields}}{sup 3}H{sub 6} transition of Tm{sup 3+} ions in Tm{sup 3+}:NaLa{sub 1/2}Gd{sub 1/2}(WO{sub 4}){sub 2} crystals pumped by a diode laser is obtained for the first time. The {pi}- and {sigma}-polarised laser radiation at wavelengths of 1908 and 1918 nm was generated with a slope efficiency of 28% and 25%, respectively. (lasers)

  14. Novel Solution Process for Fabricating Ultra-Thin-Film Absorber Layers in Fe2SiS4sub> and Fe2GeS4sub> Photovoltaics

    SciTech Connect

    Orefuwa, Samuel A.; Lai, Cheng-Yu; Dobson, Kevin D.; Ni, Chaoying; Radu, Daniela R.

    2014-05-12

    Fe2SiS4sub> and Fe2GeS4sub> crystalline materials posses direct bandgaps of ~1.55 and ~1.4 eV respectively and an absorption coefficient larger than 10^5 cm–1; their theoretical potential as solar photovoltaic absorbers has been demonstrated. However, no solar devices that employ either Fe2SiS4sub> or Fe2GeS4sub> have been reported to date. In the presented work, nanoprecursors to Fe2SiS4sub> and Fe2GeS4sub> have been fabricated and employed to build ultra-thin-film layers via spray coating and rod coating methods. Temperature-dependent X-Ray diffraction analyses of nanoprecursors coatings show an unprecedented low temperature for forming crystalline Fe2SiS4sub> and Fe2GeS4sub>. Fabricating of ultra-thin-film photovoltaic devices utilizing Fe2SiS4sub> and Fe2GeS4sub> as solar absorber material is presented.

  15. Characterization of nanosized Al{sub 2}(WO{sub 4}){sub 3}

    SciTech Connect

    Nihtianova, D.; Velichkova, N.; Nikolova, R.; Koseva, I.; Yordanova, A.; Nikolov, V.

    2011-11-15

    Graphical abstract: TEM method allows to detect small quantities of impurities not detectable by other methods. In our case impurities of W{sub 5}O{sub 14} are detected in Al{sub 2}(WO{sub 4}){sub 3} nanopowder. Highlights: {yields} Nanosized Al{sub 2}(WO{sub 4}){sub 3} by simple co-precipitation method. {yields} Spherical particles with mean size of 22 nm distributed between 10 and 40 nm at 630 {sup o}C. {yields} XRD, DTA and TEM confirm well defined products with perfect structure. {yields} TEM locality allows detection of impurities not detectable by XRD and DTA. -- Abstract: Nanosized aluminum tungstate Al{sub 2}(WO{sub 4}){sub 3} was prepared by co-precipitation reaction between Na{sub 2}WO{sub 4} and Al(NO{sub 3}){sub 3} aqueous solutions. The powder size and shape, as well as size distribution are estimated after different conditions of powder preparation. The purity of the final product was investigated by XRD and DTA analyses, using the single crystal powder as reference. Between the specimen and the reference no difference was detected. The crystal structure of Al{sub 2}(WO{sub 4}){sub 3} nanosized powder was confirmed by TEM (SAED, HRTEM). In additional, TEM locality allows to detect some W{sub 5}O{sub 14} impurities, which are not visible by conventional X-ray powder diffraction and thermal analyses.

  16. The superionic phase transitions in (NH{sub 4}){sub 3}H(SeO{sub 4}){sub 2} under hydrostatic pressure up to 400 MPa

    SciTech Connect

    Lindner, Ł.; Zdanowska-Frączek, M. Pawłowski, A.; Frączek, Z. J.

    2014-10-28

    The effect of hydrostatic pressure on proton conductivity of (NH{sub 4}){sub 3}H(SeO{sub 4}){sub 2} superionic crystal was studied in a wide temperature range and different isobaric conditions by means of impedance spectroscopy method. The measurements were performed along the trigonal c axis of the crystal, i.e., along the direction perpendicular to the plane in which, in the superionic phases, a dynamically disordered H-bond network is formed. The obtained pressure-temperature phase diagram is linear with increasing pressure. The triple point, which is the point of coexistence of the three phases: ferroelastic phase IV, ferroelastic phase III, and superionic phase II was found at p = 116.3 MPa and T = 287.3 K. High pressure leads to increase in the temperature range of stability of both superionic phases and to a drastic decrease in the temperature width of the ferroelastic phase III. With increasing pressure, the range of the superionic phase II expands at the expense of the range of the ferroelastic phase III, which is unstable and vanishes at the triple point.

  17. Shape resonances in the photoionization of CF4sub>

    SciTech Connect

    Stephens, J. A.; Dill, Dan; Dehmer, Joseph L.

    1986-01-01

    Calculations of photoionization cross sections and photoelectron angular distributions have been performed for all occupied orbitals of CF4sub> using the multiple-scattering model. Results are compared with very recent experiments which employ synchrotron radiation to measure these quantities, namely the measurements of Truesdale e t a l. for the carbonK shell, and measurements of Carlson e t a l. and Novak e t a l. for the five outermost valence levels. The calculations predict intense shape resonances below 3 eV in continua of a1 and t2 final state symmetry. Qualitative agreement is attained on comparing much of the theory with experiment, notably the five outer valence levels, which serves to establish a one-electron picture of the photoionization dynamics of CF4sub>.

  18. Sub-nanosecond Yb:KLu(WO4sub>)2 microchip laser.

    PubMed

    Loiko, P; Serres, J M; Mateos, X; Yumashev, K; Yasukevich, A; Petrov, V; Griebner, U; Aguiló, M; Díaz, F

    2016-06-01

    A diode-pumped Yb:KLu(WO4sub>)2 microchip laser passively Q-switched by a Cr4+:YAG saturable absorber generated a maximum average output power of 590 mW at 1031 nm with a slope efficiency of 55%. The pulse characteristics were 690 ps/47.6 μJ at a pulse repetition frequency of 12.4 kHz. The output beam had an excellent circular profile with M2<1.05. Yb:KLu(WO4sub>)2 is very promising for ultrathin sub-ns microchip lasers.

  19. Role of APOBEC3F Gene Variation in HIV-1 Disease Progression and Pneumocystis Pneumonia.

    PubMed

    An, Ping; Penugonda, Sudhir; Thorball, Christian W; Bartha, Istvan; Goedert, James J; Donfield, Sharyne; Buchbinder, Susan; Binns-Roemer, Elizabeth; Kirk, Gregory D; Zhang, Wenyan; Fellay, Jacques; Yu, Xiao-Fang; Winkler, Cheryl A

    2016-03-01

    Human APOBEC3 cytidine deaminases are intrinsic resistance factors to HIV-1. However, HIV-1 encodes a viral infectivity factor (Vif) that degrades APOBEC3 proteins. In vitro APOBEC3F (A3F) anti-HIV-1 activity is weaker than A3G but is partially resistant to Vif degradation unlike A3G. It is unknown whether A3F protein affects HIV-1 disease in vivo. To assess the effect of A3F gene on host susceptibility to HIV- acquisition and disease progression, we performed a genetic association study in six well-characterized HIV-1 natural cohorts. A common six-Single Nucleotide Polymorphism (SNP) haplotype of A3F tagged by a codon-changing variant (p. I231V, with allele (V) frequency of 48% in European Americans) was associated with significantly lower set-point viral load and slower rate of progression to AIDS (Relative Hazards (RH) = 0.71, 95% CI: 0.56, 0.91) and delayed development of pneumocystis pneumonia (PCP) (RH = 0.53, 95% CI: 0.37-0.76). A validation study in the International Collaboration for the Genomics of HIV (ICGH) showed a consistent association with lower set-point viral load. An in vitro assay revealed that the A3F I231V variant may influence Vif mediated A3F degradation. Our results provide genetic epidemiological evidence that A3F modulates HIV-1/AIDS disease progression.

  20. Role of APOBEC3F Gene Variation in HIV-1 Disease Progression and Pneumocystis Pneumonia

    PubMed Central

    An, Ping; Penugonda, Sudhir; Thorball, Christian W.; Bartha, Istvan; Goedert, James J.; Donfield, Sharyne; Buchbinder, Susan; Binns-Roemer, Elizabeth; Kirk, Gregory D.; Zhang, Wenyan; Fellay, Jacques; Yu, Xiao-Fang; Winkler, Cheryl A.

    2016-01-01

    Human APOBEC3 cytidine deaminases are intrinsic resistance factors to HIV-1. However, HIV-1 encodes a viral infectivity factor (Vif) that degrades APOBEC3 proteins. In vitro APOBEC3F (A3F) anti-HIV-1 activity is weaker than A3G but is partially resistant to Vif degradation unlike A3G. It is unknown whether A3F protein affects HIV-1 disease in vivo. To assess the effect of A3F gene on host susceptibility to HIV- acquisition and disease progression, we performed a genetic association study in six well-characterized HIV-1 natural cohorts. A common six-Single Nucleotide Polymorphism (SNP) haplotype of A3F tagged by a codon-changing variant (p. I231V, with allele (V) frequency of 48% in European Americans) was associated with significantly lower set-point viral load and slower rate of progression to AIDS (Relative Hazards (RH) = 0.71, 95% CI: 0.56, 0.91) and delayed development of pneumocystis pneumonia (PCP) (RH = 0.53, 95% CI: 0.37–0.76). A validation study in the International Collaboration for the Genomics of HIV (ICGH) showed a consistent association with lower set-point viral load. An in vitro assay revealed that the A3F I231V variant may influence Vif mediated A3F degradation. Our results provide genetic epidemiological evidence that A3F modulates HIV-1/AIDS disease progression. PMID:26942578

  1. Energy-transfer mechanisms in the CH3F-SF6 optically pumped laser

    NASA Technical Reports Server (NTRS)

    Lawandy, N. M.; Koepf, G. A.

    1980-01-01

    The power of an optically pumped CH3F laser operating on the 496-micron line has been doubled with the addition of SF6 without any corresponding increase in pump absorption. It is suggested that a near-resonant energy transfer between CH3F and SF6 followed by SF6 deactivation is the mechanism responsible for the enhancement.

  2. First-principles calculated decomposition pathways for LiBH4sub> nanoclusters

    SciTech Connect

    Huang, Zhi -Quan; Chen, Wei -Chih; Chuang, Feng -Chuan; Majzoub, Eric H.; Ozolins, Vidvuds

    2016-05-18

    Here, we analyze thermodynamic stability and decomposition pathways of LiBH4sub> nanoclusters using grand-canonical free-energy minimization based on total energies and vibrational frequencies obtained from density-functional theory (DFT) calculations. We consider (LiBH4sub>)n nanoclusters with n = 2 to 12 as reactants, while the possible products include (Li)n, (B)n, (LiB)n, (LiH)n, and Li2BnHn; off-stoichiometric LinBnHm (m ≤ 4n) clusters were considered for n = 2, 3, and 6. Cluster ground-state configurations have been predicted using prototype electrostatic ground-state (PEGS) and genetic algorithm (GA) based structural optimizations. Free-energy calculations show hydrogen release pathways markedly differ from those in bulk LiBH4sub>. While experiments have found that the bulk material decomposes into LiH and B, with Li2B12H12 as a kinetically inhibited intermediate phase, (LiBH4sub>)n nanoclusters with n ≤ 12 are predicted to decompose into mixed LinBn clusters via a series of intermediate clusters of LinBnHm (m ≤ 4n). The calculated pressure-composition isotherms and temperature-pressure isobars exhibit sloping plateaus due to finite size effects on reaction thermodynamics. Generally, decomposition temperatures of free-standing clusters are found to increase with decreasing cluster size due to thermodynamic destabilization of reaction products.

  3. Topotactic insertion of lithium in the layered structure Li{sub 4}VO(PO{sub 4}){sub 2}: The tunnel structure Li{sub 5}VO(PO{sub 4}){sub 2}

    SciTech Connect

    Satya Kishore, M.; Pralong, V. Caignaert, V.; Malo, S.; Hebert, S.; Varadaraju, U.V.; Raveau, B.

    2008-04-15

    A new V(III) lithium phosphate Li{sub 5}VO(PO{sub 4}){sub 2} has been synthesized by electrochemical insertion of lithium into Li{sub 4}VO(PO{sub 4}){sub 2}. This phase, which crystallizes in the space group I4/mcm, exhibits a tunnel structure closely related to the layered structure of Li{sub 4}VO(PO{sub 4}){sub 2} and to the tunnel structure of VO(H{sub 2}PO{sub 4}){sub 2}. The topotactic reactions that take place during lithium exchange and intercalation, starting from VO(H{sub 2}PO{sub 4}){sub 2} and going to the final phase Li{sub 5}VO(PO{sub 4}){sub 2} are explained on the basis of the flexible coordinations of V{sup 4+} and V{sup 3+} species. The electrochemical and magnetic properties of this new phase are also presented and explained on the basis of the structure dimensionality. - Graphical abstract: Electrochemical synthesis of a new 3D V(III) lithium phosphate, Li{sub 5}VO(PO{sub 4}){sub 2}. Starting from the 2D Li{sub 4}VO(PO{sub 4}){sub 2}, the topotactic reaction that take place during lithium intercalation is explained on the basis of the flexible coordinations of V{sup 4+} and V{sup 3+} species.

  4. Crystal Chemistry of Electrochemically and Chemically Lithiated Layered αI-LiVOPO4sub>

    SciTech Connect

    He, Guang; Bridges, Craig A.; Manthiram, Arumugam

    2015-09-14

    LiVOPO4sub> is an attractive cathode for lithium-ion batteries with a high operating voltage and the potential to achieve the reversible insertion of two lithium ions between VOPO4sub> and Li2VOPO4sub>. Among the three known forms of LiVOPO4sub> (α, β, and αI), the αI-LiVOPO4sub> has a layered structure that could promote better ionic mobility and reversibility than others. However, a comprehensive study of its lithiated product is not available as αI-LiVOPO4sub> is metastable and difficult to prepare by conventional approaches. We present here a facile synthesis of highly crystalline αI-LiVOPO4sub> and αI-LiVOPO4sub>/rGO nanocomposite by a microwave-assisted solvothermal method and its electrochemical/chemical lithiation. The LiVOPO4sub>/rGO cathodes exhibit a high reversible capacity of 225 mAh g–1, indicating the insertion of more than one lithium into VOPO4sub>. Both electrochemical and chemical lithiation imply a solid-solution reaction mechanism on inserting the second lithium into αI-LiVOPO4sub>, but a two-phase reaction feature could also occur under certain conditions such as insufficient time for equilibration of Li+ diffusion in the structure. The fully lithiated new αI-Li2VOPO4sub> phase was characterized by combined Rietveld refinement of neutron diffraction and X-ray diffraction data and by bond-valence sum maps. The results suggest that αI-Li2VOPO4sub> retains the tetragonal P4/nmm symmetry of the parent αI-LiVOPO4sub> structure, where the second lithium ions are located in the lithium layers rather than in the VOPO4sub> layers

  5. C4sub> and CAM Plant Biology Symposium 2013 Website

    SciTech Connect

    Leakey, Andrew D. B.

    2013-08-09

    This project funded the C4sub> and CAM (crassulacean acid metabolism) Plant Biology 2013 symposium, held at the University of Illinois at Urbana-Champaign, IL, on August 6-9, 2013. The symposium brought together a diverse group of scientists to discuss the evolution, ecology, functional biology, genomics and biotechnological engineering of C4sub> and CAM plants. These two groups of plants possess evolutionary modifications to their photosynthetic machinery that improve their performance in hot and dry conditions. Maize and pineapple are classic examples of C4sub> and CAM plants, respectively. The meeting discussed how lessons learned from these groups of plants can be harnessed to improve crop production of biofuel feedstocks in an era of global climate change. The interdisciplinary nature of the meeting meant that the delegation members typically do not collectively attend any one scientific society meeting. As a result, the symposium was a unique opportunity for knowledge transfer, initiation of new collaborations, and recruitment and exposure of early career scientists.

  6. Quaternary (FeIn{sub 2}S{sub 4}){sub x}(MnIn{sub 2}S{sub 4}){sub 1-x} alloys and photosensitive structures on their basis

    SciTech Connect

    Bodnar, I. V.; Rud, V. Yu.; Rud, Yu. V.; Lozhkin, D. V.

    2011-07-15

    Using directional crystallization of the melt of the (FeIn{sub 2}S{sub 4}){sub x}(MnIn{sub 2}S{sub 4}){sub 1-x} alloy, homogeneous crystals of a similar atomic composition are grown over the entire range of compositions 1 {>=} x {>=} 0. It is established that the crystals of the continuous series of quaternary alloys in the range x = 0-1 crystallize in the spinel structure and lattice parameter a linearly depends on x. It is established that it is possible to obtain In(Al)/(FeIn{sub 2}S{sub 4}){sub x}(MnIn{sub 2}S{sub 4}){sub 1-x} photosensitive structures. Room-temperature spectra of relative quantum efficiency of photoconversion of the In(Al)/(FeIn{sub 2}S{sub 4}){sub x}(MnIn{sub 2}S{sub 4}){sub 1-x} structures fabricated for the first time are obtained. From the analysis of these spectra, activation energies of direct and indirect band-to-band transitions for the crystals of the (FeIn{sub 2}S{sub 4}){sub x}(MnIn{sub 2}S{sub 4}){sub 1-x} alloys are determined and the dependence of these parameters on the composition of the position-disordered phases of mentioned alloys is discussed. It is concluded that the crystals of the (FeIn{sub 2}S{sub 4}){sub x}(MnIn{sub 2}S{sub 4}){sub 1-x} alloys can be used in broadband photoconverters of optical radiation.

  7. Neutron diffraction studies of the Na-ion battery electrode materials NaCoCr{sub 2}(PO{sub 4}){sub 3}, NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3}

    SciTech Connect

    Yahia, H. Ben; Essehli, R.; Avdeev, M.; Park, J-B.; Sun, Y-K.; Al-Maadeed, M.A.; Belharouak, I.

    2016-06-15

    The new compounds NaCoCr{sub 2}(PO{sub 4}){sub 3}, NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3} were synthesized by sol-gel method and their crystal structures were determined by using neutron powder diffraction data. These compounds were characterized by galvanometric cycling and cyclic voltammetry. NaCoCr{sub 2}(PO{sub 4}){sub 3}, NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3} crystallize with a stuffed α-CrPO{sub 4}-type structure. The structure consists of a 3D-framework made of octahedra and tetrahedra that are sharing corners and/or edges generating channels along [100] and [010], in which the sodium atoms are located. Of significance, in the structures of NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3} a statistical disorder Ni{sup 2+}/Cr{sup 3+} was observed on both the 8g and 4a atomic positions, whereas in NaCoCr{sub 2}(PO{sub 4}){sub 3} the statistical disorder Co{sup 2+}/Cr{sup 3+} was only observed on the 8g atomic position. When tested as negative electrode materials, NaCoCr{sub 2}(PO{sub 4}){sub 3}, NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3} delivered specific capacities of 352, 385, and 368 mA h g{sup −1}, respectively, which attests to the electrochemical activity of sodium in these compounds. - Highlights: • NaCoCr{sub 2}(PO{sub 4}){sub 3}, NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3} were synthesized by sol-gel method. • The crystal structures were determined by using neutron powder diffraction data. • The three compounds crystallize with a stuffed α-CrPO{sub 4}-type structure. • The three compounds were tested as anodes in sodium-ion batteries. • Relatively high specific capacities were obtained for these compounds.

  8. Hormonal Regulation and Distinct Functions of Semaphorin-3B and Semaphorin-3F in Ovarian Cancer

    PubMed Central

    Joseph, Doina; Ho, Shuk-Mei; Syed, Viqar

    2009-01-01

    Semaphorins comprise a family of molecules that influence neuronal growth and guidance. Class-3 semaphorins, semaphorin-3B (SEMA3B) and semaphorin-3F (SEMA3F) illustrate their effects by forming a complex with neuropilins (NP-1 or NP-2) and plexins. We examined the status and regulation of semaphorins and their receptors in human ovarian cancer cells. A significantly reduced expression of SEMA3B (83 kD), SEMA3F (90 kD), and plexin-A3 was observed in ovarian cancer (OVCA) cell lines when compared to normal human ovarian surface epithelial (HOSE) cells. The expression of NP-1, NP-2 and plexin-A1 was not altered in HOSE and OVCA cells. The decreased expression of SEMA3B, SEMA3F, and plexin-A3 was confirmed in stage 3 ovarian tumors. Treatment of OVCA cells with luteinizing hormone, follicle-stimulating hormone, and estrogen induced a significant upregulation of SEMA3B, whereas SEMA3F was upregulated only by estrogen. Co-treatment of cell lines with a hormone and its specific antagonist blocked the effect of the hormone. Ectopic expression of SEMA3B or SEMA3F reduced soft-agar colony formation, adhesion, and cell invasion of OVCA cell cultures. Forced expression of SEMA3B, but not SEMA3F, inhibited viability of OVCA cells. Overexpression of SEMA3B and SEMA3F reduced focal adhesion kinase (FAK) phosphorylation and matrix metalloproteinase (MMP)-2 and -9 expression in OVCA cells. Forced expression of SEMA3F, but not SEMA3B in OVCA cells, significantly inhibited endothelial cell tube formation. Collectively, our results suggest loss of SEMA3 expression could be a hallmark of cancer progression. Furthermore, gonadotropin- and/or estrogen-mediated maintenance of SEMA3 expression could control ovarian cancer angiogenesis and metastasis. PMID:20124444

  9. Collisional narrowing by polyatomic buffer gases in an optically pumped CH3F laser

    NASA Technical Reports Server (NTRS)

    Lawandy, N. M.; Koepf, G. A.

    1980-01-01

    The gain linewidth of an optically pumped CH3F molecular laser is observed with the addition of various polyatomic buffer gases. This is interpreted as collisional (Dicke) narrowing. The measurement is the first observation of collisional narrowing by polyatomic buffer gases. It is also the first observation of the effect in a laser oscillator. The effect was observed using a heterodyne mixing technique at the laser emission frequency of 604 GHz. Collision cross sections for SF6-CH3F and CS2-CH3F are obtained.

  10. Integrated Data Collection Analysis (IDCA) Program - KClO4sub>/Carbon Mixture

    SciTech Connect

    Sandstrom, Mary M.; Brown, Geoffrey W.; Preston, Daniel N.; Pollard, Colin J.; Warner, Kirstin F.; Sorensen, Daniel N.; Remmers, Daniel L.; Shelley, Timothy J.; Reyes, Jose A.; Hsu, Peter C.; Reynolds, John G.

    2013-01-31

    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of a mixture of KClO4sub> and activated carbon—KClO4sub>/C mixture. This material was selected because of the challenge of performing SSST testing of a mixture of two solids. The mixture was found to be insensitive to impact, friction, and thermal stimulus, and somewhat sensitive to spark discharge. This effort, funded by the Department of Homeland Security (DHS), ultimately will put the issues of safe handling of these materials in perspective with standard military explosives. The study is adding SSST testing results for a broad suite of different HMEs to the literature. Ultimately the study has the potential to suggest new guidelines and methods and possibly establish the SSST testing accuracies needed to develop safe handling practices for HMEs. Each participating testing laboratory uses identical test materials and preparation methods wherever possible. Note, however, the test procedures differ among the laboratories. The results are compared among the laboratories and then compared to historical data from various sources. The testing performers involved for the KClO4sub>/carbon mixture are Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Indian Head Division, Naval Surface Warfare Center, (NSWC IHD), and Air Force Research Laboratory (AFRL/RXQL). These tests are conducted as a proficiency study in order to establish some consistency in test protocols, procedures, and experiments and to understand how to compare results when these testing variables cannot be made consistent.

  11. Discovery of a metastable Al20Sm4sub> phase

    SciTech Connect

    Ye, Z.; Zhang, F.; Sun, Y.; Mendelev, M. I.; Ott, R. T.; Park, E.; Besser, M. F.; Kramer, M. J.; Ding, Z.; Wang, C. -Z.; Ho, K. -M.

    2015-03-09

    In this study, we present an efficient genetic algorithm, integrated with experimental diffraction data, to solve a nanoscale metastable Al20Sm4sub> phase that evolves during crystallization of an amorphous magnetron sputtered Al90Sm10 alloy. The excellent match between calculated and experimental X-ray diffraction patterns confirms an accurate description of this metastable phase. Molecular dynamic simulations of crystal growth from the liquid phase predict the formation of disordered defects in the devitrified crystal.

  12. Integrated Data Collection Analysis (IDCA) program--KClO4sub>/Dodecane Mixture

    SciTech Connect

    Sandstrom, Mary M.; Brown, Geoffrey W.; Preston, Daniel N.; Pollard, Colin J.; Warner, Kirstin F.; Sorensen, Daniel N.; Remmers, Daniel L.; Shelley, Timothy J.; Reyes, Jose A.; Hsu, Peter C.; Reynolds, John G.

    2012-05-11

    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of a mixture of KClO4sub> and dodecane—KClO4sub>/dodecane mixture. This material was selected because of the challenge of performing SSST testing of a mixture of solid and liquid materials. The mixture was found to: 1) be less sensitive to impact than RDX, and PETN, 2) less sensitive to friction than RDX and PETN, and 3) less sensitive to spark than RDX and PETN. The thermal analysis showed little or no exothermic features suggesting that the dodecane volatilized at low temperatures. A prominent endothermic feature was observed and assigned to a phase transition of KClO4sub>. This effort, funded by the Department of Homeland Security (DHS), ultimately will put the issues of safe handling of these materials in perspective with standard military explosives. The study is adding SSST testing results for a broad suite of different HMEs to the literature. Ultimately the study has the potential to suggest new guidelines and methods and possibly establish the SSST testing accuracies needed to develop safe handling practices for HMEs. Each participating testing laboratory uses identical test materials and preparation methods wherever possible. Note, however, the test procedures differ among the laboratories. The results are compared among the laboratories and then compared to historical data from various sources. The testing performers involved for the KClO4sub>/dodecane mixture are Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Indian Head Division, Naval Surface Warfare Center, (NSWC IHD), and Air Force Research Laboratory (AFRL/RXQL). These tests are conducted as a proficiency study in order to establish some

  13. Electron-impact dissociation cross sections for CHF3 and C3F8

    NASA Astrophysics Data System (ADS)

    Baio, J. E.; Yu, H.; Flaherty, D. W.; Winters, H. F.; Graves, D. B.

    2007-11-01

    Absolute total dissociation cross sections, σt,diss, by electron-impact are reported for CHF3 and C3F8 from 10 to 300 eV using the chemical gettering technique described by Winters and Inokuti (1982 Phys. Rev. A 25 1420). Data are concentrated in the near-threshold region (10-30 eV). The thresholds for dissociation of CHF3 and C3F8 are determined to be 10.4 eV and 11.9 eV, respectively. Ionization thresholds occur at 16 eV for CHF3 and 16.2 eV for C3F8. Neutral dissociation cross sections of both CHF3 and C3F8 are obtained by subtracting the ionization cross sections, σt,ion, from the total dissociation cross sections, σt,diss.

  14. Semaphorin 3F expression is reduced in pregnancy complicated by preeclampsia. An observational clinical study

    PubMed Central

    Stallone, Giovanni; Matteo, Maria; Netti, Giuseppe Stefano; Infante, Barbara; Di Lorenzo, Adelaide; Prattichizzo, Clelia; Carlucci, Stefania; Trezza, Federica; Gesualdo, Loreto; Greco, Pantaleo

    2017-01-01

    Background and objective Preeclampsia is a systemic disorder, affecting 2–10% of pregnancies, characterized by a deregulated pro- and anti-angiogenic balance. Semaphorin 3F is an angiogenesis inhibitor. We aimed to investigate whether semaphorin 3F expression is modulated in preeclampsia. Design, setting, participants, and measurements We performed two observational single center cohort studies between March 2013 and August 2014. In the first we enrolled 110 consecutive women, undergoing an elective cesarean section; in the second we included 150 consecutive women undergoing amniocentesis for routine clinical indications at 16–18 week of gestation. Semaphorin 3F concentration was evaluated in maternal peripheral blood, venous umbilical blood and amniotic fluid, along with its placenta protein expression at the time of delivery in the first study group and in the amniotic fluid at 16–18 weeks of gestation in the second study group. Results In the first study 19 patients presented at delivery with preeclampsia. Semaphorin 3F placenta tissue expression was significantly reduced in preeclampsia. In addition, semaphorin 3F level at delivery was significantly lower in serum, amniotic fluid and venous umbilical blood of preeclamptic patients compared with normal pregnant women. In the prospective cohort study 14 women developed preeclampsia. In this setting, semaphorin 3F amniotic level at 16–18 weeks of gestation was reduced in women who subsequently developed preeclampsia compared to women with a normal pregnancy. ROC curve analysis showed that semaphorin 3F amniotic levels could identify women at higher risk of preeclampsia. Conclusions Semaphorin 3F might represent a predictive biomarker of preeclampsia. PMID:28350837

  15. Elasticity and magnetocaloric effect in MnFe4sub>Si3

    SciTech Connect

    Herlitschke, Marcus; Klobes, B.; Sergueev, I.; Hering, Paul; Persson, Joerg; Hermann, Raphael P.

    2016-03-16

    The room temperature magnetocaloric material MnFe4sub>Si3 was investigated with nuclear inelastic scattering (NIS) and resonant ultrasound spectroscopy (RUS) at different temperatures and applied magnetic fields in order to assess the infuence of the magnetic transition and the magnetocaloric effect on the lattice dynamics. The NIS data give access to phonons with energies above 3 meV, whereas RUS probes the elasticity of the material in the MHz frequency range and thus low energy, ~5 neV, phonon modes. A significant infuence of the magnetic transition on the lattice dynamics is observed only in the low energy region. Here, MnFe4sub>Si3 and other compounds in the Mn5-xFexSi3 series were also investigated with vibrating sample magnetometry, resistivity measurements and Moessbauer spectroscopy in order to study the magnetic transitions and to complement the obtained results on the lattice dynamics.

  16. A dispersive treatment of Kl4sub> decays

    SciTech Connect

    Colangelo, Gilberto; Passemar, Emilie; Stoffer, Peter

    2015-04-28

    Kl4sub> decays offer several reasons of interest: they allow an accurate measurement of ππ-scattering lengths; they provide the best source for the determination of some low-energy constants of xPT; one form factor is directly related to the chiral anomaly, which can be measured here. We present a dispersive treatment of Kl4sub> decays that provides a resummation of ππ- and Kπ-rescattering effects. In addition, the free parameters of the dispersion relation are fitted to the data of the high-statistics experiments E865 and NA48/2. The matching toxPT at NLO and NNLO enables us to determine the LECs Lr1, Lr2 and Lr3. With recently published data from NA48/2, the LEC Lr9 can be determined as well. In contrast to a pure chiral treatment, the dispersion relation describes the observed curvature of one of the form factors, which we understand as a rescattering effect beyond NNLO.

  17. Distinct H3F3A and H3F3B driver variants define chondroblastoma and giant cell tumour of bone

    PubMed Central

    Presneau, Nadège; Scheipl, Susanne; Pillay, Nischalan; Van Loo, Peter; Wedge, David C; Cooke, Susanna L; Gundem, Gunes; Davies, Helen; Nik-Zainal, Serena; Martin, Sancha; McLaren, Stuart; Goodie, Victoria; Robinson, Ben; Butler, Adam; Teague, Jon W; Halai, Dina; Khatri, Bhavisha; Myklebost, Ola; Baumhoer, Daniel; Jundt, Gernot; Hamoudi, Rifat; Tirabosco, Roberto; Amary, M Fernanda; Futreal, P Andrew; Stratton, Michael R; Campbell, Peter J; Flanagan, Adrienne M

    2013-01-01

    It is recognised that some mutated cancer genes contribute to the development of many cancer types whilst others are cancer-type specific. Amongst genes that affect multiple cancer classes, mutations are usually similar in the different cancer types. Here, however, we observed exquisite tumour-type specificity of different histone 3.3 driver mutations. In 73/77 (95%) cases of chondroblastoma we found K36M mutations predominantly in H3F3B, which is one of two genes encoding histone 3.3. By contrast, 92% (49/53) of giant cell tumours of bone harboured histone 3.3 variants exclusively in H3F3A, which were G34W or, in one case, G34L. The mutations were restricted to the stromal cell population and not detected in osteoclasts or their precursors. In the context of previously reported H3F3A K27M and G34R/V mutations of childhood brain tumours, a remarkable picture of tumour-type specificity of histone 3.3 mutations emerges, indicating distinct functions of histone 3.3 residues, mutations and genes. PMID:24162739

  18. Energy transfer rates of KY3F10:Yb:Nd:Tm crystals

    NASA Astrophysics Data System (ADS)

    Courrol, L. C.; Linhares, H. M. S. M. D.; Librantz, A. F. H.; Baldochi, S. L.; Gomes, L.; Ranieri, I. M.

    2010-11-01

    In this work we present the spectroscopic properties of KY3F10 (KY3F) single crystals doped with thulium and also co-doped with ytterbium and/or neodymium, KY3F:Yb:Nd:Tm and KY3F:Nd:Tm. The most important processes that lead to the thulium up conversion emissions were identified. The absorption spectra of the samples were measured at room temperature in the range of 200 nm-1200 nm. The emission spectra were obtained by exciting the samples with a 797 nm laser diode and were analyzed using a lock-in amplifier technique. A time-resolved luminescence spectroscopy technique was employed to measure the luminescence decays and to determine the mechanisms involved in the energy transfer up-conversion processes. Analysis of the energy transfer processes dynamics in KY3F:Yb:Tm:Nd crystal, using selective pulsed-laser excitations, shows that the energy transfer from Nd3+ to Yb3+ ions is the mechanism responsible for the enhancement of the blue up-conversion efficiency when compared with the Yb:Tm system. In the case of KY3F:Nd:Tm it is observed emissions at 350, 355 and 452 nm excited by an additional Yb:Tm step cross relaxation, Yb (2F5/2) : Tm (1G4) that populates the 1D2 (Tm3+) excited level. A study of the energy transfer processes in KY3F:Yb:Tm:Nd crystal showed that the 1G4 excited level is mainly populated by the sequence of two nonradiative energy processes that starts well after the Nd3+ and Tm3+ excitation at 797nm: Nd (4F3/2) → Yb (2F7/2) followed by Yb (2F5/2) → Tm (3H4) → Tm (1G4).

  19. Synthesis, structure, and optical properties of CsU{sub 2}(PO{sub 4}){sub 3}

    SciTech Connect

    Oh, George N.; Ringe, Emilie; Van Duyne, Richard P.; Ibers, James A.

    2012-01-15

    CsU{sub 2}(PO{sub 4}){sub 3} was synthesized in highest yield by the reaction in a fused-silica tube of U, P, and Se in a CsCl flux at 1273 K. It crystallizes with four formula units in space group P2{sub 1}/n of the monoclinic system in a new structure type. The structure of CsU{sub 2}(PO{sub 4}){sub 3} is composed of U and Cs atoms coordinated by PO{sub 4}{sup 3-} units in distorted octahedral arrangements. Each U atom corner shares with six PO{sub 4}{sup 3-} units. Each Cs atom face shares with one, edge shares with two, and corner shares with three PO{sub 4}{sup 3-} units. The structure shares some features with the sodium zirconium phosphate structure type. X-ray powder diffraction results demonstrate that the present CsU{sub 2}(PO{sub 4}){sub 3} compound crystallizes in a structure different from the previously reported {beta} Prime - and {gamma}-CsU{sub 2}(PO{sub 4}){sub 3} compounds. CsU{sub 2}(PO{sub 4}){sub 3} is highly pleochroic, as demonstrated by single-crystal optical absorption measurements. - Graphical abstract: Stacking of the layers in CsU{sub 2}(PO{sub 4}){sub 3}, viewed along [100]. Highlights: Black-Right-Pointing-Pointer Compound CsU{sub 2}(PO{sub 4}){sub 3} crystallizes in a new structure type. Black-Right-Pointing-Pointer Structure shares some features with the sodium zirconium phosphate structure type. Black-Right-Pointing-Pointer CsU{sub 2}(PO{sub 4}){sub 3} is highly pleochroic, as demonstrated by single-crystal optical absorption measurements.

  20. Theoretical kinetics of O + C2H4sub>

    SciTech Connect

    Li, Xiaohu; Jasper, Ahren W.; Zádor, Judit; Miller, James A.; Klippenstein, Stephen J.

    2016-06-01

    The reaction of atomic oxygen with ethylene is a fundamental oxidation step in combustion and is prototypical of reactions in which oxygen adds to double bonds. For 3O+C2H4sub> and for this class of reactions generally, decomposition of the initial adduct via spin-allowed reaction channels on the triplet surface competes with intersystem crossing (ISC) and a set of spin-forbidden reaction channels on the ground-state singlet surface. The two surfaces share some bimolecular products but feature different intermediates, pathways, and transition states. In addition, the overall product branching is therefore a sensitive function of the ISC rate. The 3O+C2H4sub> reaction has been extensively studied, but previous experimental work has not provided detailed branching information at elevated temperatures, while previous theoretical studies have employed empirical treatments of ISC. Here we predict the kinetics of 3O+C2H4sub> using an ab initio transition state theory based master equation (AITSTME) approach that includes an a priori description of ISC. Specifically, the ISC rate is calculated using Landau–Zener statistical theory, consideration of the four lowest-energy electronic states, and a direct classical trajectory study of the product branching immediately after ISC. The present theoretical results are largely in good agreement with existing low-temperature experimental kinetics and molecular beam studies. Good agreement is also found with past theoretical work, with the notable exception of the predicted product branching at elevated temperatures. Above ~1000 K, we predict CH2CHO+H and CH2+CH2O as the major products, which differs from the room temperature preference for CH3+HCO (which is assumed to remain at higher temperatures in some models) and from the prediction of a previous detailed master equation study.

  1. Heat capacity and neutron diffraction studies on the frustrated magnetic Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} [0{<=}x{<=}1] solid solution

    SciTech Connect

    Pedro, I. de; Rojo, J.M.; Rodriguez Fernandez, J.; Sanchez Marcos, J.; Fernandez-Diaz, M.T.; Rojo, T.

    2012-04-15

    The Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} [0{<=}x{<=}1] solid solution exhibits a complex magnetic behaviour due to the bond-frustration in its magnetic structure. Heat capacity measurements of the (x=0.1-0.5) phases show a three-dimensional magnetic ordering ({lambda} anomaly) that shifts to lower temperatures and becomes broader as the AsO{sub 4}{sup 3-} content increases. For x=0.75, no significant feature was observed whereas for higher arsenate ion content, x=0.9 and 1, a small maximum was detected. The magnetic structures of solid solution are consistent with the existence of predominant antiferromagnetic superexchange interactions through the |OH| and |XO{sub 4}| (X=P and As) groups between the Co{sup +2} ions. The substitution of PO{sub 4}{sup 3-} by AsO{sub 4}{sup 3-} anions by more than 90% substantially modifies the magnetic exchange pathways in the solid solution, leading to an incommensurate antiferromagnetic structure in Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} [x=0.9 and 1] phases. - Graphical abstract: Magnetic structures of Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} [0{<=}x{<=}1]. The ordering of the magnetic moments of Co{sup 2+} is in c direction for the two crystallographic positions (dimers and chains) in all compounds. The unit cell is surrounded by a red line. Highlights: Black-Right-Pointing-Pointer Synthesis of a new adamite-type compounds, Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} (0.1, 0.25, 0.5, 0.75, 0.9) phases. Black-Right-Pointing-Pointer Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} (0-1) solid solution; magnetic frustrated system. Black-Right-Pointing-Pointer High resolution neutron powder diffraction to determine the crystal structures. Black-Right-Pointing-Pointer Incommensurate magnetic structures at low temperature. Black-Right-Pointing-Pointer Magnetostructural correlations in cobalt-based Co{sub 2}(OH)XO{sub 4} (X=P and As) insulation compounds.

  2. Pressure-induced phase transitions in multiferroic RbFe(MoO{sub 4}){sub 2}-Raman scattering study

    SciTech Connect

    Maczka, M.; Ptak, M.; Luz-Lima, C.; Freire, P.T.C.; Paraguassu, W.; Guerini, S.; Hanuza, J.

    2011-10-15

    High pressure Raman scattering experiments were performed on RbFe(MoO{sub 4}){sub 2}. These experiments revealed that two phase transitions take place in RbFe(MoO{sub 4}){sub 2} at very low pressures, i.e. between ambient pressure and 0.2 GPa and between 0.4 and 0.7 GPa. Raman results showed that at the first phase transition the room temperature P3-bar m1 phase transforms into the P3-bar phase, which is also observed at ambient pressure below 190 K. The second pressure-induced phase transition occurs into a low symmetry phase of unknown symmetry. The performed lattice dynamics calculations for the P3-bar m1 phase and ab initio calculation of the structural changes under hydrostatic pressure helped us to get better insights into the mechanism of the observed phase transitions. - Graphical abstract: Raman spectra of RbFe(MoO{sub 4}){sub 2} crystal in the high wavenumber region recorded at different pressures during compression experiment. Highlights: > RbFe(MoO{sub 4}){sub 2} exhibits two pressure-induced phase transitions below 0.7 GPa. > First phase transition is from the P3-bar m1 into P3-bar structure. > Phase transitions in RbFe(MoO{sub 4}){sub 2} are similar as in KFe(MoO{sub 4}){sub 2}. > Transitions' pressures are much lower for the rubidium compound.

  3. A reduced graphene oxide/Co3O4sub> composite for supercapacitor electrode

    SciTech Connect

    Xiang, Chengcheng; Li, Ming; Zhi, Mingjia; Manivannan, Ayyakkannu; Wu, Nianqiang

    2013-03-01

    20 nm sized Co3O4sub> nanoparticles are in-situ grown on the chemically reduced graphene oxide (rGO) sheets to form a rGO-Co3O4sub> composite during hydrothermal processing. The rGO-Co3O4sub> composite is employed as the pseudocapacitor electrode in the 2 M KOH aqueous electrolyte solution. The rGOCo3O4sub> composite electrode exhibits a specific capacitance of 472 F/g at a scan rate of 2 mV/s in a two-electrode cell. 82.6% of capacitance is retained when the scan rate increases to 100 mV/s. The rGOCo3O4sub> composite electrode shows high rate capability and excellent long-term stability. It also exhibits high energy density at relatively high power density. The energy density reaches 39.0 Wh/kg at a power density of 8.3 kW/kg. The super performance of the composite electrode is attributed to the synergistic effects of small size and good redox activity of the Co3O4sub> particles combined with high electronic conductivity of the rGO sheets.

  4. Second harmonic generation of diamond-blade diced KTiOPO4sub> ridge waveguides.

    PubMed

    Chen, Chen; Rüter, Christian E; Volk, Martin F; Chen, Cheng; Shang, Zhen; Lu, Qingming; Akhmadaliev, Shavkat; Zhou, Shengqiang; Chen, Feng; Kip, Detlef

    2016-07-25

    We report on the fabrication of ridge waveguides in KTiOPO4sub> nonlinear optical crystals through carbon ion irradiation followed by precise diamond blade dicing. The diced side-walls have low roughness, which allows for low propagation loss of ~1dB/cm in fabricated of ridges. The waveguide property investigation has been performed at 1064 nm as well as 532 nm, showing good guidance at both TE and TM polarizations. Based on type II phase matching configuration, efficient second harmonic generation of green light at room temperature has been realized. High conversion efficiencies of ~1.12%W-1 and ~12.4% have been obtained for frequency doubling under the pump of continuous-wave (CW) and pulsed fundamental waves at 1064 nm, respectively.

  5. Anomalous magnetic structure and spin dynamics in magnetoelectric LiFePO4sub>

    SciTech Connect

    Toft-Petersen, Rasmus; Reehuis, Manfred; Jensen, Thomas B. S.; Andersen, Niels H.; Li, Jiying; Le, Manh Duc; Laver, Mark; Niedermayer, Christof; Klemke, Bastian; Lefmann, Kim; Vaknin, David

    2015-07-06

    We report significant details of the magnetic structure and spin dynamics of LiFePO4sub> obtained by single-crystal neutron scattering. Our results confirm a previously reported collinear rotation of the spins away from the principal b axis, and they determine that the rotation is toward the a axis. In addition, we find a significant spin-canting component along c. Furthermore, the possible causes of these components are discussed, and their significance for the magnetoelectric effect is analyzed. Inelastic neutron scattering along the three principal directions reveals a highly anisotropic hard plane consistent with earlier susceptibility measurements. While using a spin Hamiltonian, we show that the spin dimensionality is intermediate between XY- and Ising-like, with an easy b axis and a hard c axis. As a result, it is shown that both next-nearest neighbor exchange couplings in the bc plane are in competition with the strongest nearest neighbor coupling.

  6. Design and Properties Prediction of AMCO3F by First-Principles Calculations.

    PubMed

    Tian, Meng; Gao, Yurui; Ouyang, Chuying; Wang, Zhaoxiang; Chen, Liquan

    2017-04-10

    Computer simulation accelerates the rate of identification and application of new materials. To search for new materials to meet the increasing demands of secondary batteries with higher energy density, the properties of some transition-metal fluorocarbonates ([CO3F](3-)) were simulated in this work as cathode materials for Li- and Na-ion batteries based on first-principles calculations. These materials were designed by substituting the K(+) ions in KCuCO3F with Li(+) or Na(+) ions and the Cu(2+) ions with transition-metal ions such as Fe(2+), Co(2+), Ni(2+), and Mn(2+) ions, respectively. The phase stability, electronic conductivity, ionic diffusion, and electrochemical potential of these materials were calculated by first-principles calculations. After taking comprehensive consideration of the kinetic and thermodynamic properties, LiCoCO3F and LiFeCO3F are believed to be promising novel cathode materials in all of the calculated AMCO3F (A = Li and Na; M = Fe, Mn, Co, and Ni). These results will help the design and discovery of new materials for secondary batteries.

  7. Two-Dimensional Nb-Based M 4sub> C 3 Solid Solutions (MXenes)

    SciTech Connect

    Yang, Jian; Naguib, Michael; Ghidiu, Michael; Pan, Li-Mei; Gu, Jian; Nanda, Jagjit; Halim, Joseph; Gogotsi, Yury; Barsoum, Michel W.; Zhou, Y.

    2015-10-15

    Two new two-dimensional Nb4sub>C3-based solid solutions (MXenes), (Nb0.8,Ti0.2)4sub>C3Tx and (Nb0.8,Zr0.2)4sub>C3Tx (where T is a surface termination) were synthesizedas confirmed by X-ray diffractionfrom their corresponding MAX phase precursors (Nb0.8,Ti0.2)4sub>AlC3 and (Nb0.8,Zr0.2)4sub>AlC3. In our report we discuss Zr-containing MXene. We also studied intercalation of Li ions into these two compositions, and Nb4sub>C3Tx in order to determine the potential of those materials for energy storage applications. Lithiation and delithiation peaks at 2.26 and 2.35 V, respectively, appeared in the case of Nb4sub>C3Tx, but were not present in Nb2CTx. After 20 cycles at a rate of C/4, the specific capacities of (Nb0.8,Ti0.2)4sub>C3Txand (Nb0.8,Ti0.2)4sub>C3Tx were 158 and 132 mAh/g, respectively, both slightly lower than the capacity of Nb4sub>C3Tx.

  8. Synthesis and characterization of KY3F10:Yb:Nd:Tm crystals

    NASA Astrophysics Data System (ADS)

    Silva, H. M.; Courrol, L. C.; Gomes, L.; Bertram, R.; Baldochi, S. L.; Ranieri, I. M.

    2010-11-01

    Energy transfer processes that generate thulium blue and ultraviolet emissions by upconversion were studied in KY3F10:Tm (KY3F:Tm), using Nd3+ and Yb3+ as sensitizers of Tm3+. The upconversion mechanisms were determined by exciting into the Nd and Tm absorption bands with a diode laser at 797nm. It was observed that the intensity of the Tm3+ blue and ultraviolet emissions in 484, 453, 366 and 350 nm were very dependent of the Yb3+ concentration in the samples, confirming that the main energy transfer processes involve Nd3+ and Yb3+ ions. KY3F10:Nd (1.3 mol%):Tm (0.5 mol%) crystals codoped with 5, 10, 20 and 30 mol% Yb were prepared by slow cooling from the melt, to establish the optimal Yb concentration that maximizes the Nd3+→Yb3+→Tm3+ energy transfer.

  9. APOBEC3G and APOBEC3F Act in Concert To Extinguish HIV-1 Replication

    PubMed Central

    Krisko, John F.; Begum, Nurjahan; Baker, Caroline E.

    2016-01-01

    ABSTRACT The multifunctional HIV-1 accessory protein Vif counters the antiviral activities of APOBEC3G (A3G) and APOBEC3F (A3F), and some Vifs counter stable alleles of APOBEC3H (A3H). Studies in humanized mice have shown that HIV-1 lacking Vif expression is not viable. Here, we look at the relative contributions of the three APOBEC3s to viral extinction. Inoculation of bone marrow/liver/thymus (BLT) mice with CCR5-tropic HIV-1JRCSF (JRCSF) expressing a vif gene inactive for A3G but not A3F degradation activity (JRCSFvifH42/43D) displayed either no or delayed replication. JRCSF expressing a vif gene mutated to inactivate A3F degradation but not A3G degradation (JRCSFvifW79S) always replicated to high viral loads with variable delays. JRCSF with vif mutated to lack both A3G and A3F degradation activities (JRCSFvifH42/43DW79S) failed to replicate, mimicking JRCSF without Vif expression (JRCSFΔvif). JRCSF and JRCSFvifH42/43D, but not JRCSFvifW79S or JRCSFvifH42/43DW79S, degraded APOBEC3D. With one exception, JRCSFs expressing mutant Vifs that replicated acquired enforced vif mutations. These mutations partially restored A3G or A3F degradation activity and fully replaced JRCSFvifH42/43D or JRCSFvifW79S by 10 weeks. Surprisingly, induced mutations temporally lagged behind high levels of virus in blood. In the exceptional case, JRCSFvifH42/43D replicated after a prolonged delay with no mutations in vif but instead a V27I mutation in the RNase H coding sequence. JRCSFvifH42/43D infections exhibited massive GG/AG mutations in pol viral DNA, but in viral RNA, there were no fixed mutations in the Gag or reverse transcriptase coding sequence. A3H did not contribute to viral extinction but, in combination with A3F, could delay JRCSF replication. A3H was also found to hypermutate viral DNA. IMPORTANCE Vif degradation of A3G and A3F enhances viral fitness, as virus with even a partially restored capacity for degradation outgrows JRCSFvifH42/43D and JRCSFvifW79S. Unexpectedly

  10. Contrast harmonic detection with chirp excitation in 3f0 transmit phasing.

    PubMed

    Shen, Che-Chou; Wang, Hong-Wei; Chiu, Yi-Yuan

    2008-10-01

    The method of third harmonic (3f0 transmit phasing is capable of providing effective tissue background suppression for contrast-to-tissue ratio (CTR) improvement in harmonic imaging. With the additional 3f0 transmit signal to generate both the frequency-sum and the frequency-difference components of harmonic signal, the tissue suppression is achieved when the two components are opposite in phase and mutually cancel out. One major problem in 3f0 transmit phasing is the limited signal-to-noise ratio (SNR) due to the constraint on transmit amplitude. Chirp excitation can be applied in contrast harmonic imaging to enhance the SNR with minimal destruction of the microbubbles. In this paper, the effect of chirp waveform in combination with the 3f0 transmit phasing was studied using both in-vitro experiments and simulations. Our results indicate that, though the chirp transmit pulse can increase the SNR of harmonic imaging in 3f0 transmit phasing (3 dB, p < 0.001), it suffers from degraded tissue harmonic suppression and thus provides less CTR improvement as compared to a conventional pulse. The spectral mismatch between the frequency-sum and the frequency-difference components of tissue harmonic signal is particularly evident in the off-center region of second harmonic band, leading to significant residue tissue background. Consequently, with the chirp waveform, the improvement of CTR decreases from 9.5 dB to 5.9 dB (p < 0.0006) and thus a tradeoff exists between the SNR improvement and the CTR improvement in 3f0 transmit phasing.

  11. Thermal properties and phase transition in the fluoride, (NH{sub 4}){sub 3}SnF{sub 7}

    SciTech Connect

    Kartashev, A.V.; Gorev, M.V.; Bogdanov, E.V.; Flerov, I.N.; Laptash, N.M.

    2016-05-15

    Calorimetric, dilatometric and differential thermal analysis studies were performed on (NH{sub 4}){sub 3}SnF{sub 7} for a wide range of temperatures and pressures. Large entropy (δS{sub 0}=22 J/mol K) and elastic deformation (δ(ΔV/V){sub 0}=0.89%) jumps have proven that the Pa-3↔Pm-3m phase transition is a strong first order structural transformation. A total entropy change of ΔS{sub 0}=32.5 J/mol K is characteristic for the order–disorder phase transition, and is equal to the sum of entropy changes in the related material, (NH{sub 4}){sub 3}TiF{sub 7}, undergoing transformation between the two cubic phases through the intermediate phases. Hydrostatic pressure decreases the stability of the high temperature Pm-3m phase in (NH{sub 4}){sub 3}SnF{sub 7}, contrary to (NH{sub 4}){sub 3}TiF{sub 7}, characterised by a negative baric coefficient. The effect of experimental conditions on the chemical stability of (NH{sub 4}){sub 3}SnF{sub 7} was observed. - Graphical abstract: Strong first order structural transformation Pa-3↔Pm-3m in (NH{sub 4}){sub 3}SnF{sub 7} is associated with very large total entropy change of ΔS{sub 0}=32.5 J/mol K characteristic for the ordering processes and equal to the sum of entropy changes in the related (NH{sub 4}){sub 3}TiF{sub 7} undergoing transformation between the same two cubic phases through the intermediate phases. - Highlights: • (NH{sub 4}){sub 3}SnF{sub 7} undergoes strong first order Pa-3↔Pm-3m phase transition. • Anomalous behaviour of ΔC{sub p} and ΔV/V exists far below phase transition temperature. • Structural distortions are accompanied by huge total entropy change ΔS≈Rln50. • High pressure strongly increases the stability of Pa-3 phase in (NH{sub 4}){sub 3}SnF{sub 7}. • Entropy of the Pa-3↔Pm-3m phase transition does not depend on pressure.

  12. Luminescence properties of phosphate phosphor Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+}

    SciTech Connect

    Yang, Fu; Liu, Yufeng; Tian, Xiaodong; Dong, Guoyi; Yu, Quanmao

    2015-05-15

    A series of reddish orange-emitting phosphate phosphors Ba{sub 3}Y{sub 1−x}(PO{sub 4}){sub 3}:xSm{sup 3+}(0.01≤x≤0.20) were synthesized by solid-state reaction. X-ray diffraction and photoluminescence spectra were utilized to characterize the structure and luminescence properties of as-synthesized phosphors. The optimized phosphors Ba{sub 3}Y{sub 0.95}(PO{sub 4}){sub 3}:0.05Sm{sup 3+} present several excitation bands from 300 to 500 nm, and exhibit intense reddish orange-emitting properties. The energy transfer type between Sm{sup 3+} ions was confirmed as d–d interaction by using Van Uitert model. The chromatic properties of the typical sample Ba{sub 3}Y(PO{sub 4}){sub 3}:0.05Sm{sup 3+} phosphor have been found to have chromaticity coordinates of (0.583, 0.405), which are located in reddish orange region under the excitation of 401 nm. These results indicated that Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+} phosphors have potential applications in the field of lighting and display due to their effective excitation in the near-ultraviolet range. - Graphical abstract: The color coordinates for 5 mol% Sm{sup 3+} doped Ba{sub 3}Y(PO{sub 4}){sub 3} phosphor were calculated to be (0.583, 0.405), which are located in reddish orange region under the excitation of 401 nm. The peaks of Ba{sub 3}Y{sub 0.95}(PO{sub 4}){sub 3}:0.05Sm{sup 3+} phosphor with the highest emission intensity at 600 nm are broader than those of Y{sub 2}O{sub 3}:Eu{sup 3+} and Y{sub 2}O{sub 2}S:Eu{sup 3+} phosphors. All these characteristics suggest that Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+} phosphors are suitable for near-UV (370–410 nm) excitation and can be applicable to near UV-based WLEDs. ▪ - Highlights: • Different concentration Sm{sup 3+}-doped Ba{sub 3}Y(PO{sub 4}){sub 3} phosphors were fabricated by solid state method. • The optimized phosphors present the several excitation bands from 300 to 500 nm. • The Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+} shows bright reddish orange

  13. Insights into the structure of mixed CO2/CH4sub> in gas hydrates

    SciTech Connect

    Everett, S. Michelle; Rawn, Claudia J.; Chakoumakos, Bryan C.; Keffer, David J.; Huq, Ashfia; Phelps, Tommy J.

    2015-05-12

    The exchange of carbon dioxide for methane in natural gas hydrates is an attractive approach to harvesting CH4sub> for energy production while simultaneously sequestering CO2. In addition to the energy and environmental implications, the solid solution of clathrate hydrate (CH4sub>)1-x(CO2)x·5.75H2O provides a model system to study how the distinct bonding and shapes of CH4sub> and CO2 influence the structure and properties of the compound. In this paper, high-resolution neutron diffraction was used to examine mixed CO2/CH4sub> gas hydrates. CO2-rich hydrates had smaller lattice parameters, which were attributed to the higher affinity of the CO2 molecule interacting with H2O molecules that form the surrounding cages, and resulted in a reduction in the unit-cell volume. Experimental nuclear scattering densities illustrate how the cage occupants and energy landscape change with composition. Finally, these results provide important insights on the impact and mechanisms for the structure of mixed CH4sub>/CO2 gas hydrate.

  14. Magnetic structures of the {alpha}-Li{sub 3}Fe{sub 2}(PO{sub 4}){sub 3-} {sub x} (AsO{sub 4}) {sub x} (x=1, 1.5, 2, 3) solid solution

    SciTech Connect

    Goni, Aintzane; Wattiaux, Alain; Olazcuaga, Roger; Isabel Arriortua, Maria . E-mail: teo.rojo@ehu.es

    2006-01-15

    Moessbauer spectroscopy and neutron diffraction studies have been carried out for the {alpha}-Li{sub 3}Fe{sub 2}(PO{sub 4}){sub 3-} {sub x} (AsO{sub 4}) {sub x} (x=1, 1.5, 2, 3) solid solution, potential candidate for the cathode material of the lithium secondary batteries. The crystal and magnetic structures of all these phases are based on the structural and magnetic model corresponding to the {alpha}-Li{sub 3}Fe{sub 2}(PO{sub 4}){sub 3} phosphate parent, but with some differences promoted by the arsenate substitution. The PO{sub 4} and AsO{sub 4} groups have a random distribution in the structure. In all compounds the coupling of the magnetic moments takes place in the (001) plane, but the value of the angle between the moments and the x direction decreases from 38.3 deg. ({alpha}-Li{sub 3}Fe{sub 2}(AsO{sub 4}){sub 3}) to 4.7{sup o} ({alpha}-Li{sub 3}Fe{sub 2}(PO{sub 4}){sub 2}(AsO{sub 4}){sub 1}). This rotation arises from the change in the tilt angle between the Fe(1)O{sub 6} and Fe(2)O{sub 6} crystallographically and magnetically independent octahedra in the structures, and affects the effectiveness of the magnetic exchange pathways. The ordering temperature T{sub N} decreases with the increase of phosphate amount in the compounds. The existence of a phenomenon of canting and the evolution of the ferrimagnetic behavior in this solid solution is also discussed.

  15. Hepatitis E virus genotype 3f sequences from pigs in Thailand, 2011-2012.

    PubMed

    Keawcharoen, Juthatip; Thongmee, Thanunrat; Panyathong, Raphee; Joiphaeng, Pichai; Tuanthap, Supansa; Oraveerakul, Kanisak; Theamboonlers, Apiradee; Poovorawan, Yong

    2013-04-01

    Phylogenetic analysis of partial ORF1 and ORF2 genes of Hepatitis E virus (HEV) strains from pigs in Thailand during 2011-2012 was performed. The result indicated that the current Thai strains belonged to the genotype 3 subgroup 3f, which were similar to the previous HEVs circulating in humans in Thailand.

  16. Census of Population and Housing, 1980: Summary Tape File 3F. Technical Documentation.

    ERIC Educational Resources Information Center

    Bureau of the Census (DOC), Washington, DC. Data User Services Div.

    This report provides technical documentation associated with a 1980 Census of Population and Housing Summary Tape File (STF) 3F--which contains responses to the extended questionnaire summarized in STF 3, aggregated by school district. The file contains sample data inflated to represent the total population, 100% counts, and unweighted sample…

  17. 48 CFR 47.305-3 - F.o.b. origin solicitations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false F.o.b. origin... CONTRACT MANAGEMENT TRANSPORTATION Transportation in Supply Contracts 47.305-3 F.o.b. origin solicitations. When preparing f.o.b. origin solicitations, the contracting officer shall refer to 47.303, where...

  18. 48 CFR 47.305-3 - F.o.b. origin solicitations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false F.o.b. origin... CONTRACT MANAGEMENT TRANSPORTATION Transportation in Supply Contracts 47.305-3 F.o.b. origin solicitations. When preparing f.o.b. origin solicitations, the contracting officer shall refer to 47.303, where...

  19. 48 CFR 47.303-3 - F.o.b. origin, freight allowed.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false F.o.b. origin, freight... CONTRACT MANAGEMENT TRANSPORTATION Transportation in Supply Contracts 47.303-3 F.o.b. origin, freight allowed. (a) Explanation of delivery term. F.o.b. origin, freight allowed means— (1) Free of expense...

  20. 48 CFR 47.303-3 - F.o.b. origin, freight allowed.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false F.o.b. origin, freight... CONTRACT MANAGEMENT TRANSPORTATION Transportation in Supply Contracts 47.303-3 F.o.b. origin, freight allowed. (a) Explanation of delivery term. F.o.b. origin, freight allowed means— (1) Free of expense...

  1. COMPARATIVE EVALUATION OF R3f GARNET BEAD FILTRATION AND MULTIMEDIA FILTRATION SYSTEMS; FINAL REPORT

    EPA Science Inventory

    This report summarizes the results of tests conducted to date at the EPA T&E Facility on the R3f filtration system utilizing fine beads (such as garnet beads or glass beads) and a conventional multimedia filtration system. Both systems have been designed and built by Enprotec, a...

  2. Soft A4sub>→Z3 symmetry breaking and cobimaximal neutrino mixing

    SciTech Connect

    Ma, Ernest

    2016-03-28

    In this study, I propose a model of radiative charged-lepton and neutrino masses with A4sub> symmetry. The soft breaking of A4sub> to Z3 lepton triality is accomplished by dimension-three terms. The breaking of Z3 by dimension-two terms allows cobimaximal neutrino mixing (θ13 ≠ 0, θ23 = π/4, δcp=π/2) to be realized with only very small finite calculable deviations from the residual Z3 lepton triality. This construction solves a long-standing technical problem inherent in renormalizable A4sub> models since their inception.

  3. Spin Hall magnetoresistance in CoFe2O4sub>/Pt films

    SciTech Connect

    Wu, Hao; Qintong, Zhang; Caihua, Wan; Ali, Syed Shahbaz; Yuan, Zhonghui; You, Lu; Wang, Junling; Choi, Yongseong; Han, Xiufeng

    2015-05-13

    Pulse laser deposition and magnetron sputtering techniques have been employed to prepare MgO(001)//CoFe2O4sub>/Pt samples. Cross section transmission electron microscope results prove that the CoFe2O4sub> film epitaxially grew along (001) direction. X-ray magnetic circular dichroism results show that magnetic proximity effect in this sample is negligible. Magnetoresistance (MR) properties confirm that spin Hall MR (SMR) dominates in this system. Spin Hall effect-induced anomalous Hall voltage was also observed in this sample. Lastly, these results not only demonstrate the universality of SMR effect but also demonstrate the utility in spintronics of CoFe2O4sub> as a new type of magnetic insulator.

  4. Mechanisms for pressure-induced crystal-crystal transition, amorphization, and devitrification of Snl4sub>

    SciTech Connect

    Liu, Hanyu; Tse, John S.; Hu, Michael Y.; Bi, Wenli; Zhao, Jiyong; Alp, E. Ercan; Pasternak, Moshe; Taylor, R. Dean; Lashley, Jason C.

    2015-10-27

    The pressure-induced amorphization and subsequent recrystallization of SnI4sub> have been investigated using first principles molecular dynamics calculations together with high-pressure 119Sn nuclear resonant inelastic x-ray scattering measurements. Above ~8 GPa, we observe a transformation from an ambient crystalline phase to an intermediate crystal structure and a subsequent recrystallization into a cubic phase at ~64 GPa. The crystalline-to-amorphous transition was identified on the basis of elastic compatibility criteria. The measured tin vibrational density of states shows large amplitude librations of SnI4sub> under ambient conditions. Although high pressure structures of SnI4sub> were thought to be determined by random packing of equal-sized spheres, we detected electron charge transfer in each phase. As a result, this charge transfer results in a crystal structure packing determined by larger than expected iodine atoms. (C) 2015 AIP Publishing LLC.

  5. Dispersed sites of HIV Vif-dependent polyubiquitination in the DNA deaminase APOBEC3F

    PubMed Central

    Albin, John S.; Anderson, John S.; Johnson, Jeffrey R.; Harjes, Elena; Matsuo, Hiroshi; Krogan, Nevan J.; Harris, Reuben S.

    2013-01-01

    APOBEC3F and APOBEC3G are DNA cytosine deaminases that potently restrict Human Immunodeficiency Virus-type 1 replication when the virus is deprived of its accessory protein Vif. Vif counteracts these restriction factors by recruiting APOBEC3F and APOBEC3G to an E3 ubiquitin ligase complex that mediates their polyubiquitination and proteasomal degradation. While previous efforts have identified single amino acid residues in APOBEC3 proteins required for Vif recognition, less is known about the downstream ubiquitin acceptor sites that are targeted. One prior report identified a cluster of polyubiquitinated residues in APOBEC3G and proposed an antiparallel model of APOBEC3G interaction with the Vif-E3 ubiquitin ligase complex wherein Vif binding at one terminus of APOBEC3G orients the opposite terminus for polyubiquitination [Iwatani Y, et al. (2009) PNAS 106(46):19539–19544]. To test the generalizability of this model, we carried out a complete mutagenesis of the lysine residues in APOBEC3F and used a complementary, unbiased proteomic approach to identify ubiquitin acceptor sites targeted by Vif. Our data indicate that internal lysines are the dominant ubiquitin acceptor sites in both APOBEC3F and APOBEC3G. In contrast with the proposed antiparallel model, however, we find that the Vif-dependent polyubiquitination of APOBEC3F and APOBEC3G can occur at multiple acceptor sites dispersed along predicted lysine-enriched surfaces of both the N- and C-terminal deaminase domains. These data suggest an alternative model for binding of APOBEC3 proteins to the Vif-E3 ubiquitin ligase complex and diminish enthusiasm for the amenability of APOBEC3 ubiquitin acceptor sites to therapeutic intervention. PMID:23318957

  6. [C3F8 in the treatment of retinal detachment associated with vitreoretinal proliferation].

    PubMed

    Fleury, J; Bonnet, M

    1989-01-01

    The perfluoropropane gas was used as an adjunct to vitreoretinal microsurgery in 60 eyes of 60 patients with rhegmatogenous retinal detachment complicated by proliferative vitreoretinopathy. 0.3 ml to 1.8 ml (average 0.9 ml) of pure perfluoropropane gas was used. The surgical procedure included vitrectomy and scleral buckling in all patients. The follow-up after complete gas absorption ranged from 6 months to 3 years in the successful eyes. Total retinal reattachment was achieved in 41 eyes (68.3%). The anatomical success rate was 88% (22/25 eyes) in grade C1-C2 PVR cases, 68.7% (11/15 eyes) in grade C3-D1 PVR cases, and 42% (8/19 eyes) in grade D2-D3 PVR cases. Visual acuity of 0.1 or better was achieved in 80% of eyes with grade C PVR and 61% of eyes with grade D PVR. Visual acuity of 0.4 or better was achieved in 26.9% of eyes with grade C PVR. Macular changes were revealed by fluorescein angiography in 53% of successful eyes. We recommend the use of C3F8 rather than SF6 in the management of rhegmatogenous retinal detachment complicated by PVR. In our experience the anatomical success rate achieved with C3F8 is approximately the same as that achieved with SF6. However permanent retinal reattachment was achieved with a single operation in 87.8% of successful eyes of the present series of patients managed with C3F8 as compared to only 12% of successful eyes of a previous series of patients managed with SF6. The anatomical results achieved with a single operation in the C3F8 series are probably related to the greater longevity of C3F8 as compared to that of SF6.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Biodiesel production using lipase immobilized on epoxychloropropane-modified Fe3O4 sub-microspheres.

    PubMed

    Zhang, Qian; Zheng, Zhong; Liu, Changxia; Liu, Chunqiao; Tan, Tianwei

    2016-04-01

    Superparamagnetic Fe3O4 sub-microspheres with diameters of approximately 200 nm were prepared via a solvothermal method, and then modified with epoxychloropropane. Lipase was immobilized on the modified sub-microspheres. The immobilized lipase was used in the production of biodiesel fatty acid methyl esters (FAMEs) from acidified waste cooking oil (AWCO). The effects of the reaction conditions on the biodiesel yield were investigated using a combination of response surface methodology and three-level/three-factor Box-Behnken design (BBD). The optimum synthetic conditions, which were identified using Ridge max analysis, were as follows: immobilized lipase:AWCO mass ratio 0.02:1, fatty acid:methanol molar ratio 1:1.10, hexane:AWCO ratio 1.33:1 (mL/g), and temperature 40 °C. A 97.11% yield was obtained under these conditions. The BBD and experimental data showed that the immobilized lipase could generate biodiesel over a wide temperature range, from 0 to 40 °C. Consistently high FAME yields, in excess of 80%, were obtained when the immobilized lipase was reused in six replicate trials at 10 and 20 °C.

  8. A high performance hybrid battery based on aluminum anode and LiFePO4sub> cathode

    SciTech Connect

    Sun, Xiao-Guang; Bi, Zhonghe; Liu, Hansan; Bridges, Craig A.; Paranthaman, Mariappan Parans; Dai, Sheng; Brown, Gilbert M.

    2015-12-07

    A unique battery hybrid utilizes an aluminum anode, a LiFePO4sub> cathode and an acidic ionic liquid electrolyte based on 1-ethyl-3-methylimidazolium chloride (EMImCl) and aluminum trichloride (AlCl 3) (EMImCl-AlCl 3, 1-1.1 in molar ratio) with or without LiAlCl4sub> is proposed. This hybrid ion battery delivers an initial high capacity of 160 mAh g-1 at a current rate of C/5. It also shows good rate capability and cycling performance.

  9. Structural and conductivity studies of CsK(SO{sub 4}){sub 0.32}(SeO{sub 4}){sub 0.68}Te(OH){sub 6}

    SciTech Connect

    Djemel, M.; Abdelhedi, M.; Dammak, M.; Kolsi, A.W.

    2012-12-15

    The compound CsK(SO{sub 4}){sub 0.32}(SeO{sub 4}){sub 0.68}Te(OH){sub 6} crystallizes in the monoclinic P2{sub 1}/n space group. It was analyzed, at room temperature, using X-ray diffractometer data. The main feature of these atomic arrangements is the coexistence of three and different anions (SO{sub 4}{sup 2-}, SeO{sub 4}{sup 2-} and TeO{sub 6}{sup 6-}groups) in the unit cell, connected by hydrogen bonds which make the building of the crystal. The thermal analysis of the title compound shows three distinct endothermal peaks at 435, 460 and 475 K. Complex impedance measurements are performed on this material as a function of both temperature and frequency. The electric conduction has been studied. The temperature dependence on the conductivity indicates that the sample became an ionic conductor at high temperature. - Graphical abstract: Projection of crystal structure CsK(SO{sub 4}){sub 0.32}(SeO{sub 4}){sub 0.68}Te(OH){sub 6} on the ab plane. Highlights: Black-Right-Pointing-Pointer We have studied the results of the crystal structure of the new mixed compound. Black-Right-Pointing-Pointer We have characterized the phase transition observed in DSC curve. Black-Right-Pointing-Pointer The protonic conduction in our material is probably due to a hopping mechanism.

  10. Theoretical Study of the Molecular and Electronic Structures of TiO4sub>H4sub>, Ti2O7H6, and Ti2O6H4sub>

    SciTech Connect

    Tsuchiya, Takashi; Whitten, Jerry L.

    2010-12-22

    State-of-the-art multistate configuration interaction (CI) calculations were performed for a series of titanium complexes, namely, TiO4sub>H4sub>, Ti2O7H6, and Ti2O6H4sub>, which were chosen to identify features present in titanium oxide nanoclusters and titanium dioxide surfaces. All electrons were included in the calculations, and transformation methods were employed to achieve high accuracy for the excitations of interest. The electronic structures of the ground and excited states are discussed, and excitation energies are reported for different molecular conformations. Of particular interest is the extent of localization of the electron-hole pair formed upon excitation from the oxygen 2p molecular orbitals. Singlet and triplet excited states were resolved, and energies of electronic states are reported as a function of molecular geometry.

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

    SciTech Connect

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

    2011-08-15

    Tb{sup 3+}, Yb{sup 3+}, Tm{sup 3+}, Er{sup 3+}, and Ho{sup 3+} doped Ca{sub 3}(PO{sub 4}){sub 2} were synthesized by solid-state reaction, and their luminescence properties were studied by spectra techniques. Tb{sup 3+}-doped samples can exhibit intense green emission under VUV excitation, and the brightness for the optimal Tb{sup 3+} content is comparable with that of the commercial Zn{sub 2}SiO{sub 4}:Mn{sup 2+} green phosphor. Under near-infrared laser excitation, the upconversion luminescence spectra of Yb{sup 3+}, Tm{sup 3+}, Er{sup 3+}, and Ho{sup 3+} doped samples demonstrate that the red, green, and blue tricolored fluorescence could be obtained by codoping Yb{sup 3+}-Ho{sup 3+}, Yb{sup 3+}-Er{sup 3+}, and Yb{sup 3+}-Tm{sup 3+} in Ca{sub 3}(PO{sub 4}){sub 2}, respectively. Good white upconversion emission with CIE chromaticity coordinates (0.358, 0.362) is achieved by quadri-doping Yb{sup 3+}-Tm{sup 3+}-Er{sup 3+}-Ho{sup 3+} in Ca{sub 3}(PO{sub 4}){sub 2}, in which the cross-relaxation process between Er{sup 3+} and Tm{sup 3+}, producing the {sup 1}D{sub 2}-{sup 3}F{sub 4} transition of Tm{sup 3+}, is found. The upconversion mechanisms are elucidated through the laser power dependence of the upconverted emissions and the energy level diagrams. - Graphical abstract: The CPO:0.25Tb{sup 3+}, 0.25Na{sup +} exhibits a comparable brightness to the commercial Zn{sub 2}SiO{sub 4}:Mn{sup 2+} upon 147 nm excitation. Good white light color is achieved in CPO:Yb{sup 3+}-Tm{sup 3+}-Er{sup 3+}-Ho{sup 3+} under 980 nm excitation. Highlights: > Ca{sub 3}(PO{sub 4}){sub 2}:Tb{sup 3+},Na{sup +} exhibits a comparable brightness with commercial Zn{sub 2}SiO{sub 4}:Mn{sup 2+}. > Red, green and blue colors are achieved in Yb{sup 3+}, Ho{sup 3+}, Er{sup 3+}, Tm{sup 3+} doped Ca{sub 3}(PO{sub 4}){sub 2}. > Good white emission is obtained in Yb{sup 3+}-Ho{sup 3+}-Er{sup 3+}-Tm{sup 3+} quadri-doped Ca{sub 3}(PO{sub 4}){sub 2}. > Ca{sub 3}(PO{sub 4}){sub 2}:Tb{sup 3+}, Yb{sup 3+}, Ho

  12. ATRX immunostaining predicts IDH and H3F3A status in gliomas.

    PubMed

    Ebrahimi, Azadeh; Skardelly, Marco; Bonzheim, Irina; Ott, Ines; Mühleisen, Helmut; Eckert, Franziska; Tabatabai, Ghazaleh; Schittenhelm, Jens

    2016-06-16

    Gliomas are the most frequent intraaxial CNS neoplasms with a heterogeneous molecular background. Recent studies on diffuse gliomas have shown frequent alterations in the genes involved in chromatin remodelling pathways such as α-thalassemia/mental-retardation-syndrome-X-linked gene (ATRX). Yet, the reliability of ATRX in predicting isocitrate dehydrogenase (IDH) and H3 histone, family 3A (H3F3A) mutations in gliomas, is unclear.We analysed the ATRX expression status by immunohistochemistry, in a large series of 1064 gliomas and analysed the results in correlation to IDH, H3F3A and loss of heterozygosity (LOH) 1p/19q status in these tumors. We also investigated the prognostic potential of ATRX concerning the clinical outcome of patients with diffuse gliomas.According to our results, loss of nuclear ATRX expression was accompanied with an astrocytic tumor lineage and a younger age of onset. ATRX loss in astrocytomas was also strongly associated with IDH1/2 and H3F3A mutation (p < 0.0001). Among 196 glial tumors with nuclear ATRX loss, 173 (89 %) had an IDH1 or IDH2 mutation. Among the remaining 23 cases (11 %) with ATRX loss and IDH wild type status, 7 cases had a H3F3A G34R mutation (3 %) and 2 cases had a H3F3A K27M mutation (1 %). ATRX retention in IDH1/2 mutant tumors was strongly associated with LOH 1p/19q and oligodendroglioma histology (p < 0.0001). We also confirmed the significant prognostic role of ATRX. Diffuse gliomas with ATRX loss (n = 137, median 1413 days, 95 % CI: 1065-1860 days) revealed a significantly better clinical outcome compared with tumors with ATRX retention (n = 335, median: 609, 95 % CI: 539-760 days, HR = 1.81, p < 0.0001).In conclusion, ATRX is a potential marker for prediction of IDH/H3F3A mutations and substratification of diffuse gliomas into survival relevant tumor groups. Such classification is of great importance for further clinical decision making especially concerning the therapeutic options

  13. Crystal structure of the DNA cytosine deaminase APOBEC3F: the catalytically active and HIV-1 Vif-binding domain.

    PubMed

    Bohn, Markus-Frederik; Shandilya, Shivender M D; Albin, John S; Kouno, Takahide; Anderson, Brett D; McDougle, Rebecca M; Carpenter, Michael A; Rathore, Anurag; Evans, Leah; Davis, Ahkillah N; Zhang, Jingying; Lu, Yongjian; Somasundaran, Mohan; Matsuo, Hiroshi; Harris, Reuben S; Schiffer, Celia A

    2013-06-04

    Human APOBEC3F is an antiretroviral single-strand DNA cytosine deaminase, susceptible to degradation by the HIV-1 protein Vif. In this study the crystal structure of the HIV Vif binding, catalytically active, C-terminal domain of APOBEC3F (A3F-CTD) was determined. The A3F-CTD shares structural motifs with portions of APOBEC3G-CTD, APOBEC3C, and APOBEC2. Residues identified to be critical for Vif-dependent degradation of APOBEC3F all fit within a predominantly negatively charged contiguous region on the surface of A3F-CTD. Specific sequence motifs, previously shown to play a role in Vif susceptibility and virion encapsidation, are conserved across APOBEC3s and between APOBEC3s and HIV-1 Vif. In this structure these motifs pack against each other at intermolecular interfaces, providing potential insights both into APOBEC3 oligomerization and Vif interactions.

  14. Mixed-Valent NaCu 4sub> Se 3: A Two-Dimensional Metal

    SciTech Connect

    Sturza, Mihai; Bugaris, Daniel E.; Malliakas, Christos D.; Han, Fei; Chung, Duck Young; Kanatzidis, Mercouri G.

    2016-05-04

    The new ternary copper selenide NaCu4sub>Se3 crystallizes in the RbCd4sub>As3 structure type with the trigonal space group R3m and lattice constants a = 4.0316(4) angstrom and c = 31.438(8) angstrom. Its structure is built from two-dimensional slabs of 2 [Cu4sub>Se3] separated by Na+ cations. The compound is formally mixed-valent with Se2-/Se- atoms and exhibits metallic properties. It is a hole conductor with an electrical conductivity of similar to 300 S cm-1 at room temperature and a thermopower of similar to 10 mu V K-1. Hall effect measurements indicate holes as the dominant carrier with a concentration of similar to 6.12(1) X 1021 cm-3 at 300 K. Density functional theory electronic structure calculations indicate p -type metallic behavior for the 2 [Cu4sub>Se3] framework, which is in a good agreement with the experimental metallic conductivity and Pauli paramagnetism.

  15. A facile solvothermal synthesis of octahedral Fe3O4sub> nanoparticles

    SciTech Connect

    DuChene, Joseph S.; Qiu, Jingjing; Graham, Jeremy O.; Engelhard, Mark H.; Cao, Guixin; Gai, Zheng; Wei, Wei David; Ooi, Frances

    2015-01-26

    Anisotropic Fe3O4sub> octahedrons are obtained via a simple solvothermal synthesis with appropriate sizes for various technological applications. Here, a complete suite of materials characterization methods confirms the magnetite phase for these structures, which exhibit substantial saturation magnetization and intriguing morphologies for a wide range of applications.

  16. New mixed-valence chromium structure type: NH{sub 4}Cr(CrO{sub 4}){sub 2}

    SciTech Connect

    Casari, Barbara M. . E-mail: casari@chem.gu.se; Wingstrand, Erica; Langer, Vratislav

    2006-01-15

    Synthesis and crystal structure of a new structure type of mixed Cr(III)/Cr(VI) chromates is reported. NH{sub 4}Cr(CrO{sub 4}){sub 2} was prepared from CrO{sub 3} in the presence of (NH{sub 4}){sub 2}Ce(NO{sub 3}){sub 6}. Since this is the first preparation of mixed valence ternary chromium oxides from aqueous solution, a reaction pathway for this synthesis is suggested. The crystal structure of NH{sub 4}Cr(CrO{sub 4}){sub 2} has been determined from three-dimensional X-ray data collected at low temperature, 173K. The structure belongs to the orthorhombic space group Pnma, with a=14.5206(10), b=5.4826(4), c=8.7041(7)A and Z=4. The title compound consists of corner-sharing chromium(III) octahedra and chromium(VI) tetrahedra forming a three-dimensional network with the composition [Cr(CrO{sub 4}){sub 2}]{sub n}{sup n-}, containing channels in which zigzag rows of ammonium ions balance the net charge.

  17. Dark Matter Search Results from the PICO-2L C3F8 Bubble Chamber

    SciTech Connect

    Amole, C.; Ardid, M.; Asner, David M.; Baxter, D.; Behnke, E.; Bhattacharjee, P. S.; Borsodi, H.; Bou-Cabo, M.; Brice, S. J.; Broemmelsiek, D.; Clark, K.; Collar, J. I.; Cooper, P. S.; Crisler, M.; Dahl, C. E.; Daley, S.; Das, Madhusmita; Debris, F.; Dhungana, N.; Farine, J.; Felis, I.; Filgas, R.; Fines-Neuschild, M.; Girard, Francoise; Giroux, G.; Hai, M.; Hall, Jeter C.; Harris, O.; Jackson, C. M.; Jin, M.; Krauss, C. B.; Lafreniere, M.; Laurin, M.; Lawson, I.; Levine, I.; Lippincott, W. H.; Mann, E.; Martin, J. P.; Maurya, D.; Mitra, Pitam; Neilson, R.; Noble, A. J.; Plante, A.; Podviianiuk, R. B.; Priya, S.; Robinson, A. E.; Ruschman, M.; Scallon, O.; Seth, S.; Sonnenschein, Andrew; Starinski, N.; Stekl, I.; Vazquez-Jauregui, E.; Wells, J.; Wichoski, U.; Zacek, V.; Zhang, J.

    2015-06-12

    New data are reported from the operation of a 2-liter C3F8 bubble chamber in the 2100 meter deep SNOLAB underground laboratory, with a total exposure of 211.5 kg-days at four different recoil energy thresholds ranging from 3.2 keV to 8.1 keV. These data show that C3F8 provides excellent electron recoil and alpha rejection capabilities at very low thresholds, including the rst observation of a dependence of acoustic signal on alpha energy. Twelve single nuclear recoil event candidates were observed during the run. The candidate events exhibit timing characteristics that are not consistent with the hypothesis of a uniform time distribution, and no evidence for a dark matter signal is claimed. These data provide the most sensitive direct detection constraints on WIMP-proton spin-dependent scattering to date, with signicant sensitivity at low WIMP masses for spin-independent WIMP-nucleon scattering.

  18. Collisional narrowing in the optically pumped CH3OH and CH3F lasers

    NASA Technical Reports Server (NTRS)

    Lawandy, N. M.; Koepf, G. A.

    1982-01-01

    The gain linewidth of the optically pumped CH3F laser is observed to narrow and rebroaden with the addition of He. In addition, the same effect is observed in the CH3OH laser with the addition of the polyatomic buffer gases SF6 and CS2. These results offer conclusive evidence of the Dicke narrowing phenomena in these inverted pure rotational transitions. The effect is observed using a high harmonic mixing technique in a Schottky barrier diode.

  19. LiV2O4sub>: A heavy fermion transition metal oxide

    SciTech Connect

    Kondo, Shinichiro

    1999-02-12

    The format of this dissertation is as follows. In the remainder of Chapter 1, brief introductions and reviews are given to the topics of frustration, heavy fermions and spinels including the precedent work of LiV2O4sub>. In Chapter 2, as a general overview of this work the important publication in Physical Review Letters by the author of this dissertation and collaborators regarding the discovery of the heavy fermion behavior in LiV2O4sub> is introduced [removed for separate processing]. The preparation methods employed by the author for nine LiV2O4sub> and two Li1+xTi2-xO4sub> (x = 0 and 1/3) polycrystalline samples are introduced in Chapter 3. The subsequent structural characterization of the LiV2O4sub> and Li1+xT2-xO4sub> samples was done by the author using thermogravimetric analysis (TGA), x-ray diffraction measurements and their structural refinements by the Rietveld analysis. The results of the characterization are detailed in Chapter 3. In Chapter 4 magnetization measurements carried out by the author are detailed. In Chapter 5, after briefly discussing the resistivity measurement results including the single-crystal work by Rogers et al., for the purpose of clear characterization of LiV2O4sub> it is of great importance to introduce in the following chapters the experiments and subsequent data analyses done by his collaborators. Heat capacity measurements (Chapter 6) were carried out and analyzed by Dr. C.A. Swenson, and modeled theoretically by Dr. D.C. Johnston. In Chapter 7 a thermal expansion study using neutron diffraction by Dr. O. Chmaissem et al. and capacitance dilatometry measurements by Dr. C.A. Swenson are introduced. The data analyses for the thermal expansion study were mainly done by Dr. O. Chmaissem (for neutron diffraction) and Dr. C.A. Swendon (for dilatometry), with assistances by Dr. J

  20. Structural transformations in the Na{sub 4+x}VO(PO{sub 4}){sub 2} vanadylphosphates

    SciTech Connect

    Shpanchenko, Roman V. . E-mail: shpanchenko@icr.chem.msu.ru; Dikarev, Evgeny V.; Mironov, Andrey V.; Mudretsova, Svetlana N.; Antipov, Evgeny V.

    2006-08-15

    The crystal structures of new sodium vanadylphosphate, Na{sub 4.35}VO(PO{sub 4}){sub 2} (a=15.4450(11)A, b=14.7690(10)A, c=6.9870(5)A, Z=8, S.G. Ibam), and new ({gamma}-) modification of Na{sub 4}VO(PO{sub 4}){sub 2} (a=15.4455(15)A, b=14.8433(10)A, c=7.0081(5)A, Z=8, S.G. Pbc2{sub 1}) have been investigated by X-ray single-crystal diffraction. Both structures contain isolated infinite chains of the corner-sharing VO{sub 6} octahedra. The octahedra within the chains are additionally linked to each other by the tetrahedral PO{sub 4} groups. Sodium atoms are situated in the positions between the chains. Depending on the conditions of synthesis, the number of sodium atoms in the unit cell of the Na{sub 4+x}VO(PO{sub 4}){sub 2} compounds may vary resulting in a change of the oxidation state of vanadium atoms and a change of their coordination environment. In Na{sub 4.35}VO(PO{sub 4}){sub 2} vanadium atoms have almost regular octahedral coordination with six close V-O separations and all chains in the structure are equivalent. The crystal structure of {gamma}-Na{sub 4}VO(PO{sub 4}){sub 2} contains two non-equivalent chain types: the first one is similar to that found in Na{sub 4.35}VO(PO{sub 4}){sub 2} whereas the second one contains VO{sub 6} octahedra with the short vanadyl bonds. The charge re-distribution was supposed in the new {gamma}-modification of Na{sub 4}VO(PO{sub 4}){sub 2} where the V{sup 4+{delta}} and V{sup 4-{delta}} cations orderly occupy octahedral positions in different chains. The origin of this phenomena is discussed.

  1. Dark Matter Limits From a 2L C3F8 Filled Bubble Chamber

    SciTech Connect

    Robinson, Alan Edward

    2015-12-01

    The PICO-2L C3F8 bubble chamber search forWeakly Interacting Massive Particle (WIMP) dark matter was operated in the SNOLAB underground laboratory at the same location as the previous CF3I lled COUPP-4kg detector. Neutron calibrations using photoneutron sources in C3F8 and CF3I lled calibration bubble chambers were performed to verify the sensitivity of these target uids to dark matter scattering. This data was combined with similar measurements using a low-energy neutron beam at the University of Montreal and in situ calibrations of the PICO-2L and COUPP-4kg detectors. C3F8 provides much greater sensitivity to WIMP-proton scattering than CF3I in bubble chamber detectors. PICO-2L searched for dark matter recoils with energy thresholds below 10 keV. Radiopurity assays of detector materials were performed and the expected neutron recoil background was evaluated to be 1.6+0:3

  2. Dark matter limits from a 2L C3F8 filled bubble chamber

    NASA Astrophysics Data System (ADS)

    Robinson, Alan Edward

    The PICO-2L C3F8 bubble chamber search for Weakly Interacting Massive Particle (WIMP) dark matter was operated in the SNOLAB underground laboratory at the same location as the previous CF3I filled COUPP-4kg detector. Neutron calibrations using photoneutron sources in C3F8 and CF3I filled calibration bubble chambers were performed to verify the sensitivity of these target fluids to dark matter scattering. This data was combined with similar measurements using a low-energy neutron beam at the University of Montreal and in situ calibrations of the PICO-2L and COUPP-4kg detectors. C3F 8 provides much greater sensitivity to WIMP-proton scattering than CF 3I in bubble chamber detectors. PICO-2L searched for dark matter recoils with energy thresholds below 10 keV. Radiopurity assays of detector materials were performed and the expected neutron recoil background was evaluated to be 1.6 +0.3-0.9 single bubble events during the 211.5 kg-day exposure. Twelve single bubble dark matter candidate events were observed. These events were not uniformly distributed in time, and were likely caused by particulates in the active volume. Despite this background, PICO-2L sets a world-leading upper limit to the WIMP-proton spin dependent scattering cross-section.

  3. The factor XIIa blocking antibody 3F7: a safe anticoagulant with anti-inflammatory activities

    PubMed Central

    Worm, Marie; Köhler, Elodie C.; Panda, Rachita; Long, Andy; Butler, Lynn M.; Stavrou, Evi X.; Nickel, Katrin F.; Fuchs, Tobias A.

    2015-01-01

    The plasma protein factor XII (FXII) is the initiating protease of the procoagulant and proinflammatory contact system. FXII activates both the bradykinin (BK) producing kallikrein-kinin system and the intrinsic pathway of coagulation. Contact with negatively charged surfaces induces auto-activation of zymogen FXII that results in activated FXII (FXIIa). Various in vivo activators of FXII have been identified including heparin, misfolded protein aggregates, nucleic acids and polyphosphate. Murine models have established a central role of FXII in arterial and venous thromboembolic diseases. Despite the central function of FXII in pathologic thrombosis, its deficiency does not impair hemostasis in animals or humans. The selective role of FXIIa in thrombosis, but not hemostasis, offers an exciting novel strategy for safe anticoagulation based on interference with FXIIa. We have generated the recombinant fully human FXIIa-blocking antibody 3F7, which abolished FXIIa enzymatic activity and prevented thrombosis in a cardiopulmonary bypass system in large animals, in the absence of increased therapy-associated bleeding. Furthermore, 3F7 also interfered with BK-driven edema in the severe swelling disorder hereditary angioedema (HAE) type III. Taken together, targeting FXIIa with 3F7 appears to be a promising approach to treat edema disorders and thrombosis. PMID:26605293

  4. The Seasonal and Interannual Variability of the Budgets of N2O and CCl3F

    NASA Technical Reports Server (NTRS)

    Wong, Sun; Prather, Michael J.; Rind, David H.

    1999-01-01

    The 6-year wind archives from the Goddard Institute for Space Studies/Global Climate-Middle Atmosphere Model (GISS/GCMAM) were in- put to the GISS/Harvard/Irvine Chemical Transport Model (G/H/I CTM) to study the seasonal and interannual variability of the budgets and distributions of nitrous oxide (N2O) and trichlorofluoromethane (CCl3F), with the corresponding chemical loss frequencies recycled and boundary conditions kept unchanged from year to year. The effects of ozone feedback and quasi-biennial oscillation (QBO) were not included. However, the role of circulation variation in driving the lifetime variability is investigated. It was found that the global loss rates of these tracers are related to the extratropical planetary wave activity, which drives the tropical upward mass flux. For N2O, a semiannual signal in the loss rate variation is associated with the interhemispheric asymmetry in the upper stratospheric wave activity. For CCl3F, the semiannual signal is weaker, associated with the comparatively uniform wave episodes in the lower stratosphere. The loss rates lag behind the wave activity by about 1-2 months. The interannual variation of the GCM generated winds drives the interannual variation of the annually averaged lifetime. The year-to-year variations of the annually averaged lifetimes can be about 3% for N2O and 4% for CCl3F.

  5. [NMR structure and dynamics of the chimeric protein SH3-F2].

    PubMed

    Kutyshenko, V P; Gushchina, L V; Khristoforov, V S; Prokhorov, D A; Timchenko, M A; Kudrevatykh, Iu A; Fediukina, D V; Filimonov, V V

    2010-01-01

    For the further elucidation of structural and dynamic principles of protein self-organization and protein-ligand interactions the design of new chimeric protein SH3-F2 was made and genetically engineered construct was created. The SH3-F2 amino acid sequence consists of polyproline ligand mgAPPLPPYSA, GG linker and the sequence of spectrin SH3 domain circular permutant S19-P20s. Structural and dynamics properties of the protein were studied by high-resolution NMR. According to NMR data the tertiary structure of the chimeric protein SH3-F2 has the topology which is typical of SH3 domains in the complex with the ligand, forming polyproline type II helix, located in the conservative region of binding in the orientation II. The polyproline ligand closely adjoins with the protein globule and is stabilized by hydrophobic interactions. However the interaction of ligand and the part of globule relative to SH3 domain is not too large because the analysis of protein dynamic characteristics points to the low amplitude, high-frequency ligand tumbling in relation to the slow intramolecular motions of the main globule. The constructed chimera permits to carry out further structural and thermodynamic investigations of polyproline helix properties and its interaction with regulatory domains.

  6. Subconjunctival retention of C3F8 gas increased success rates of trabeculectomy in rabbits.

    PubMed

    Lu, D W; Chang, C J; Chiang, C H; Chou, P I

    1998-08-01

    The effect of subconjunctival retention of perfluoropropane (C3F8) gas on rabbit trabeculectomy was evaluated in this study to determine if this maneuver would increase the success rate of the surgery. Sixteen New Zealand white rabbits underwent trabeculectomy in the right eyes and trabeculectomy with subconjunctival retention of 0.3 mL C3F8 gas in the left eyes were used as animal models. One week and six weeks after the operations, the intraocular pressure (IOP) dynamics were compared between the two eyes after intravenous infusion of 0.9% NaCl sterile solution. The results showed that the average retention time of C3F8 gas within the subconjunctival space in the rabbits was 9.5 +/- 2.3 days. There were four parameters available in comparing IOP dynamics: Time Needed to Reach Peak IOP (TNRPI); Ascending Slope (AS); Peak IOP (PI) and Time Needed to Return to the Original IOP (TNROI). It was noted that at the 7th day after the operations, the IOPs in both eyes of the rabbits were not significantly increased after intravenous infusion of 0.9% NaCl solution. At the 42nd day, after 0.9% NaCl intravenous infusion, the eyes that had undergone trabeculectomy and subconjunctival retention of C3F8 gas had less IOP spiking than eyes that had undergone trabeculectomy alone (TNRPI: 6.7 +/- 2.2 vs. 4.2 +/- 2.9, p = 0.01, AS: 0.5 +/- 0.3 vs. 2.8 +/- 2.7, p = 0.002, PI: 24.4 +/- 9.6 vs. 18.7 +/- 7.4, p = 0.07 and TNROI: 6.8 +/- 5.8 vs. 14.7 +/- 11, p = 0.02). Our study suggested that subconjunctival retention of C3F8 gas increased the success rate of trabeculectomy in rabbits in the short-term follow-up period.

  7. Mechanism of Enhanced HIV Restriction by Virion Coencapsidated Cytidine Deaminases APOBEC3F and APOBEC3G.

    PubMed

    Ara, Anjuman; Love, Robin P; Follack, Tyson B; Ahmed, Khawaja A; Adolph, Madison B; Chelico, Linda

    2017-02-01

    The APOBEC3 (A3) enzymes, A3G and A3F, are coordinately expressed in CD4(+) T cells and can become coencapsidated into HIV-1 virions, primarily in the absence of the viral infectivity factor (Vif). A3F and A3G are deoxycytidine deaminases that inhibit HIV-1 replication by inducing guanine-to-adenine hypermutation through deamination of cytosine to form uracil in minus-strand DNA. The effect of the simultaneous presence of both A3G and A3F on HIV-1 restriction ability is not clear. Here, we used a single-cycle infectivity assay and biochemical analyses to determine if coencapsidated A3G and A3F differ in their restriction capacity from A3G or A3F alone. Proviral DNA sequencing demonstrated that compared to each A3 enzyme alone, A3G and A3F, when combined, had a coordinate effect on hypermutation. Using size exclusion chromatography, rotational anisotropy, and in vitro deamination assays, we demonstrate that A3F promotes A3G deamination activity by forming an A3F/G hetero-oligomer in the absence of RNA which is more efficient at deaminating cytosines. Further, A3F caused the accumulation of shorter reverse transcripts due to decreasing reverse transcriptase efficiency, which would leave single-stranded minus-strand DNA exposed for longer periods of time, enabling more deamination events to occur. Although A3G and A3F are known to function alongside each other, these data provide evidence for an A3F/G hetero-oligomeric A3 with unique properties compared to each individual counterpart.

  8. Magnetic structure of the antiferromagnetic Kondo lattice compounds CeRhAl4sub>Si2 and CeIrAl4sub>Si2

    SciTech Connect

    Ghimire, N. J.; Calder, S.; Janoschek, M.; Bauer, E. D.

    2015-06-01

    In this article, we have investigated the magnetic ground state of the antiferromagnetic Kondo-lattice compounds CeMAl4sub>Si2(M = Rh, Ir) using neutron powder diffraction. Although both of these compounds show two magnetic transitions TN1 and TN2 in the bulk properties measurements, evidence for magnetic long-range order was only found below the lower transition TN2. Analysis of the diffraction profiles reveals a commensurate antiferromagnetic structure with a propagation vector k = (0, 0, 1/2). The magnetic moment in the ordered state of CeRhAl4sub>Si2 and CeIrAl4sub>Si2 were determined to be 1.14(2) and 1.41(3) μB/Ce, respectively, and are parallel to the crystallographic c-axis in agreement with magnetic susceptibility measurements.

  9. Various disordered ground states and 1/3 magnetization-plateau-like behavior in the S =1/2 Ti3 + kagome lattice antiferromagnets Rb2NaTi3F12 , Cs2NaTi3F12 , and Cs2KTi3F12

    NASA Astrophysics Data System (ADS)

    Goto, Masato; Ueda, Hiroaki; Michioka, Chishiro; Matsuo, Akira; Kindo, Koichi; Yoshimura, Kazuyoshi

    2016-09-01

    We have investigated the crystal structure and magnetic properties of three kagome lattice antiferromagnets, Rb2Na Ti3F12 , Cs2Na Ti3F12 , and Cs2K Ti3F12 , using single crystals. These compounds represent a S =1 /2 kagome system consisting of magnetic Ti3 + ions, which is expected to have negligibly small Dzyaloshinsky-Moriya interaction. The structural analyses revealed that each of the three compounds has a slightly distorted kagome lattice. The distortion of the kagome lattice becomes small as the ionic radii of constituent alkali metals increase. All three compounds have nearly the same Weiss temperature of -45 K, and the ground states are disordered and strongly depend on the distortion. The ground states of Rb2Na Ti3F12 , Cs2Na Ti3F12 , and Cs2K Ti3F12 are found to be a two-component state including approximately 1/3 nearly free spins, a gapless disordered state, and a gapped disordered state, respectively. Our experimental results suggest that the ground state of the ideal S =1 /2 Heisenberg kagome lattice antiferromagnet is gapped. In addition, the magnetization curves of Cs2Na Ti3F12 and Cs2K Ti3F12 show anomalies at approximately 1/3 of the full magnetic moment of Ti3 +, which are a notable observation of signs of the theoretically proposed 1/3 magnetization plateau in S =1 /2 kagome antiferromagnets.

  10. Cr/B4sub>C multilayer mirrors: Study of interfaces and X-ray reflectance

    SciTech Connect

    Burcklen, C.; Soufli, R.; Gullikson, E.; Meltchakov, E.; Dennetiere, D.; Polack, F.; Capitanio, B.; Thomasset, M.; Jerome, A.; de Rossi, S.; Delmotte, F.

    2016-03-24

    Here, we present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B4sub>C multilayer interference coatings with layer thicknesses ranging from 0.7 nm to 5.4 nm. The multilayers were deposited by magnetron sputtering and by ion beam sputtering. Grazing incidence x-ray reflectometry, soft x-ray reflectometry, and transmission electron microscopy reveal asymmetric multilayer structures with a larger B4sub>C-on-Cr interface, which we modeled with a 1–1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L2,3 absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (optical constants) values for Cr.

  11. Investigation of room temperature ferromagnetic nanoparticles of Gd5Si4sub>

    SciTech Connect

    Hadimani, R. L.; Gupta, S.; Harstad, S. M.; Pecharsky, V. K.; Jiles, D. C.

    2015-07-06

    Gd5(SixGe1-x)4sub> compounds undergo first-order phase transitions close to room temperature when x ~ = 0.5, which are accompanied by extreme changes of properties. We report the fabrication of the nanoparticles of one of the parent compounds-Gd5Si4sub>-using high-energy ball milling. Crystal structure, microstructure, and magnetic properties have been investigated. Particles agglomerate at long milling times, and the particles that are milled >20 min lose crystallinity and no longer undergo magnetic phase transition close to 340 K, which is present in a bulk material. The samples milled for >20 min exhibit a slightly increased coercivity. As a result, magnetization at a high temperature of 275K decreases with the increase in the milling time.

  12. Active pulse shaping for end-pumped Nd:YVO4sub> amplifier with high gain.

    PubMed

    Nie, Mingming; Liu, Qiang; Ji, Encai; Cao, Xuezhe; Fu, Xing; Gong, Mali

    2017-03-15

    We demonstrated the active shaping for a solid-state Nd:YVO4sub> amplifier with a high average gain of 39.2 dB. The average output power was 8.3 W with respect to the input power of 1 mW. A range of common and useful pulse shapes was generated at the final output. In addition, a very flat square pulse was produced with a root-mean-square less than 3% in amplitude. A numerical method was proposed to realize active shaping without an experimental test for the Nd:YVO4sub> amplifier, showing great potential for the design of lasers with both high peak power (>100  kW) and a desired pulse shape.

  13. Stress Induced Charge-Ordering Process in LiMn2O4sub>

    SciTech Connect

    Chen, Yan; Yu, Dunji; An, Ke

    2016-07-25

    In this letter we report the stress-induced Mn charge-ordering process in the LiMn2O4sub> spinel, evidenced by the lattice strain evolutions due to the Jahn–Teller effects. In situ neutron diffraction reveals the initial stage of this process at low stress, indicating the eg electron localization at the preferential Mn sites during the early phase transition as an underlying charge-ordering mechanism in the charge-frustrated LiMn2O4sub>. The initial stage of this transition exhibits as a progressive lattice and charge evolution, without showing a first-order behavior.

  14. Effects of Nickel Doping on the Multiferroic and Magnetic Phases of MnWO 4sub>

    SciTech Connect

    Poudel, N.; Lorenz, B.; Lv, B.; Wang, Y. Q.; Ye, F.; Wang, Jinchen; Fernandez-baca, J. A.; Chu, C. W.

    2015-12-15

    There are various orders in multiferroic materials with a frustrated spiral spin modulation inducing a ferroelectric state are extremely sensitive to small perturbations such as magnetic and electric fields, external pressure, or chemical substitutions. A classical multiferroic, the mineral Hubnerite with chemical formula MnWO4sub>, shows three different magnetic phases at low temperature. The intermediate phase between 7.5K < T < 12.7K is multiferroic and ferroelectricity is induced by an inversion symmetry breaking spiral Mn-spin order and strong spin-lattice interactions. Furthermore, the substitution of Ni2+ (spin 1) for Mn2+ (spin 5/2) in MnWO4sub> and its effects on the magnetic and multiferroic phases are studied. The ferroelectric phase is stabilized for low Ni content (up to 10%). Upon further Ni doping, the polarization in the ferroelectric phase is quickly suppressed while a collinear and commensurate magnetic phase, characteristic of the magnetic structure in NiWO4sub>, appears first at higher temperature, gradually extends to lower temperature, and becomes the ground state above 30% doping. Between 10% and 30%, the multiferroic phase coexists with the collinear commensurate phase. In this concentration region, the spin spiral plane is close to the a-b plane which explains the drop of the ferroelectric polarization. Finally, the phase diagram of Mn1-xNixWO4sub> is derived by a combination of magnetic susceptibility, specific heat, electric polarization, and neutron scattering measurements.

  15. Crystal chemistry of M{sup II}M′{sup IV}(PO{sub 4}){sub 2} double monophosphates

    SciTech Connect

    Bregiroux, Damien; Popa, Karin; Wallez, Gilles

    2015-10-15

    M{sup II}M′{sup IV}(PO{sub 4}){sub 2} compounds have been extensively studied for several decades for their potential applications in the field of several domains such as matrices for actinides conditioning, phosphors etc. In this paper, the relationships between composition and crystal structure of these compounds are established. A review of the various processes used for the synthesis of these compounds is also proposed, as well as their most reported properties. M{sup II}M′{sup IV}(PO{sub 4}){sub 2} structures stem from two different archetypes: the cheralite and the yavapaiite structures, with some exceptions that are also described in this article. The ratio of the cations radii appears to be the most relevant parameter. The high ratio between the ionic radii of the divalent and tetravalent cations in yavapaiite derivates results in the ordering of these cations into well-differentiated polyhedra whereas cheralite is the only non-ordered structure encountered for M{sup II}M′{sup IV}(PO{sub 4}){sub 2} compounds. - Graphical abstract: In this paper, the relationships between composition and crystal structure of M{sup II}M′{sup IV}(PO{sub 4}){sub 2} compounds are established. A review of the various processes used for the synthesis of these compounds is also proposed, as well as their most reported properties. - Highlights: • Crystal structure–composition relationships of MIIM′IV(PO4)2 compounds. • Review of the various processes used for the synthesis of these compounds. • Their most reported properties are described and discussed.

  16. Mode-selective chemistry on metal surfaces: The dissociative chemisorption of CH4sub> on Pt(111)

    SciTech Connect

    Guo, Han; Jackson, Bret

    2016-05-13

    A quantum approach based on an expansion in vibrationally adiabatic eigenstates is used to explore CH4sub> dissociation on Pt(111). Computed sticking probabilities for molecules in the ground, 1v3 and 2v3, states are in very good agreement with the available experimental data, reproducing the variation in reactivity with collision energy and vibrational state. As was found in similar studies on Ni(100) and Ni(111), exciting the 1v1 symmetric stretch of CH4sub> is more effective at promoting the dissociative chemisorption of CH4sub> than exciting the 1v3 antisymmetric stretch. This behavior is explained in terms of symmetry, mode-softening, and nonadiabatic transitions between vibrationally adiabatic states. We find that the efficacies of the bending modes for promoting reaction are reasonably large, and similar to the 1v3 state. The vibrational efficacies for promoting reaction on Ni(111) are larger than for reaction on Pt(111), due to the larger nonadiabatic couplings. As a result, our computed sticking probabilities are in good agreement with results from recent ab initio molecular dynamics and reactive force field studies.

  17. Structural behavior of ZnCr2S4sub> spinel under pressure

    SciTech Connect

    Efthimiopoulos, I.; Lochbiler, T.; Tsurkan, V.; Loidl, A.; Felea, V.; Wang, Y.

    2016-12-15

    Here, the series of Cr-chalcogenide spinels ACr2X4sub> (A = Zn, Cd, Hg; X = S, Se) exhibits a rich phase diagram upon compression, as revealed by our recent investigations. There exist, however, some open questions regarding the role of cations in the observed structural transitions. In order to address these queries, we have performed X-ray diffraction and Raman spectroscopic studies on the ZnCr2S4sub> spinel up to 42 GPa, chosen mainly due to the similarity of the Zn2+ and Cr3+ cationic radii. Two reversible structural transitions were identified at 22 and 33 GPa, into a I4<sub>1/amd and an orthorhombic phase, respectively. Close comparison with the behavior of relevant Cr-spinels revealed that the structural transitions are mainly governed by the competition of the magnetic exchange interactions present in these systems, and not by steric effects. In addition, careful inspection of the starting Fd$\\bar{3}$m phase revealed a previously unnoticed isostructural transition. The latter is intimately related to changes in the electronic properties of these systems, as evidenced by our Raman studies. Our results provide insights for tuning the physical and chemical properties of these materials, even under moderate compression, as well as promoting the understanding of similar pressure-induced effects in relevant systems.

  18. Theoretical study of the reactions M(+)+CH(3)F (M=Ge, As, Se, Sb).

    PubMed

    Méndez, Oscar; Colmenares, Fernando

    2010-06-21

    CASSCF-MRMP2 calculations have been carried out to analyze the reactions of the methyl fluoride molecule with the atomic ions Ge(+), As(+), Se(+) and Sb(+). For these interactions, potential energy curves for the low-lying electronic states were calculated for different approaching modes of the fragments. Particularly, those channels leading to C-H and C--F oxidative addition products, H(2)FC-M-H(+) and H(3)C-M-F(+), respectively were explored, as well as the paths which evolve to the abstraction (M-F(+)+CH(3)) and the elimination (CH(2)M(+)+HF) asymptotes. For the reaction Ge(+)+CH(3)F the only favorable channel leads to fluorine abstraction by the ion. As(+) and Sb(+) can react with CH(3)F along pathways yielding stable addition products. However, a viable path joining the oxidative addition product H(3)C-M-F(+) with the elimination asymptote CH(2)M(+)+HF was found for the reaction of the fluorocarbon compound with As(+). No favorable channels were detected for the interaction of fluoromethane with Se(+). The results discussed herein allow rationalizing some of the experimental data found for these interactions through gas-phase mass spectrometry.

  19. Dark matter search results from the PICO-2L C$$_3$$F$$_8$$ bubble chamber

    DOE PAGES

    Amole, C.

    2015-06-11

    New data are reported from the operation of a 2 liter C3F8 bubble chamber in the SNOLAB underground laboratory, with a total exposure of 211.5 kg days at four different energy thresholds below 10 keV. These data show that C3F8 provides excellent electron-recoil and alpha rejection capabilities at very low thresholds. The chamber exhibits an electron-recoil sensitivity of < 3.5 × 10–10 and an alpha rejection factor of > 98.2%. These data also include the first observation of a dependence of acoustic signal on alpha energy. Twelve single nuclear recoil event candidates were observed during the run. The candidate eventsmore » exhibit timing characteristics that are not consistent with the hypothesis of a uniform time distribution, and no evidence for a dark matter signal is claimed. Lastly, these data provide the most sensitive direct detection constraints on WIMP-proton spin-dependent scattering to date, with significant sensitivity at low WIMP masses for spin-independent WIMP-nucleon scattering.« less

  20. The effect of anaesthesia on the intraocular volume of the C3F8 gas bubble.

    PubMed

    Briggs, M; Wong, D; Groenewald, C; McGalliard, J; Kelly, J; Harper, J

    1997-01-01

    Long-acting intraocular gas bubbles are frequently used during vitrectomy to tamponade retinal breaks. The aim of this study was to determine the effect of nitrous oxide anaesthesia on the size and effectiveness of the post-vitrectomy gas bubble. Twenty vitrectomy procedures with injection of 12% perfluoropropane (C3F8) gas were performed. For 10 of the cases routine anaesthesia with nitrous oxide was used and for 10 cases non-nitrous anaesthesia with propofol was used. The volume of the intraocular gas bubble was estimated 24 hours post-operatively using A-scan biometry. At 24 hours the gas bubble occupied a mean of 65.1% of the eye in anaesthesia with nitrous oxide and a mean of 66.1% in anaesthesia with intravenous propofol. The wide range of values of gas-fill recorded at 24 hours makes comparison of the two groups inappropriate. Several factors may account for this spread of values, but in our opinion it is the uncontrolled leakage from the sclerostomies which is the most likely. This study suggests that anaesthesia using nitrous oxide does not adversely affect the size of the C3F8 gas bubble at 24 hours post-vitrectomy when compared with anaesthesia without nitrous oxide.

  1. Dark Matter Search Results from the PICO-2L C3F8 Bubble Chamber.

    PubMed

    Amole, C; Ardid, M; Asner, D M; Baxter, D; Behnke, E; Bhattacharjee, P; Borsodi, H; Bou-Cabo, M; Brice, S J; Broemmelsiek, D; Clark, K; Collar, J I; Cooper, P S; Crisler, M; Dahl, C E; Daley, S; Das, M; Debris, F; Dhungana, N; Farine, J; Felis, I; Filgas, R; Fines-Neuschild, M; Girard, F; Giroux, G; Hai, M; Hall, J; Harris, O; Jackson, C M; Jin, M; Krauss, C B; Lafrenière, M; Laurin, M; Lawson, I; Levine, I; Lippincott, W H; Mann, E; Martin, J P; Maurya, D; Mitra, P; Neilson, R; Noble, A J; Plante, A; Podviianiuk, R B; Priya, S; Robinson, A E; Ruschman, M; Scallon, O; Seth, S; Sonnenschein, A; Starinski, N; Štekl, I; Vázquez-Jáuregui, E; Wells, J; Wichoski, U; Zacek, V; Zhang, J

    2015-06-12

    New data are reported from the operation of a 2 liter C3F8 bubble chamber in the SNOLAB underground laboratory, with a total exposure of 211.5 kg days at four different energy thresholds below 10 keV. These data show that C3F8 provides excellent electron-recoil and alpha rejection capabilities at very low thresholds. The chamber exhibits an electron-recoil sensitivity of <3.5×10(-10) and an alpha rejection factor of >98.2%. These data also include the first observation of a dependence of acoustic signal on alpha energy. Twelve single nuclear recoil event candidates were observed during the run. The candidate events exhibit timing characteristics that are not consistent with the hypothesis of a uniform time distribution, and no evidence for a dark matter signal is claimed. These data provide the most sensitive direct detection constraints on WIMP-proton spin-dependent scattering to date, with significant sensitivity at low WIMP masses for spin-independent WIMP-nucleon scattering.

  2. Dark Matter Search Results from the PICO-2L C3F8 Bubble Chamber

    NASA Astrophysics Data System (ADS)

    Amole, C.; Ardid, M.; Asner, D. M.; Baxter, D.; Behnke, E.; Bhattacharjee, P.; Borsodi, H.; Bou-Cabo, M.; Brice, S. J.; Broemmelsiek, D.; Clark, K.; Collar, J. I.; Cooper, P. S.; Crisler, M.; Dahl, C. E.; Daley, S.; Das, M.; Debris, F.; Dhungana, N.; Farine, J.; Felis, I.; Filgas, R.; Fines-Neuschild, M.; Girard, F.; Giroux, G.; Hai, M.; Hall, J.; Harris, O.; Jackson, C. M.; Jin, M.; Krauss, C. B.; Lafrenière, M.; Laurin, M.; Lawson, I.; Levine, I.; Lippincott, W. H.; Mann, E.; Martin, J. P.; Maurya, D.; Mitra, P.; Neilson, R.; Noble, A. J.; Plante, A.; Podviianiuk, R. B.; Priya, S.; Robinson, A. E.; Ruschman, M.; Scallon, O.; Seth, S.; Sonnenschein, A.; Starinski, N.; Štekl, I.; Vázquez-Jáuregui, E.; Wells, J.; Wichoski, U.; Zacek, V.; Zhang, J.; PICO Collaboration

    2015-06-01

    New data are reported from the operation of a 2 liter C3F8 bubble chamber in the SNOLAB underground laboratory, with a total exposure of 211.5 kg days at four different energy thresholds below 10 keV. These data show that C3F8 provides excellent electron-recoil and alpha rejection capabilities at very low thresholds. The chamber exhibits an electron-recoil sensitivity of <3.5 ×1 0-10 and an alpha rejection factor of >98.2 %. These data also include the first observation of a dependence of acoustic signal on alpha energy. Twelve single nuclear recoil event candidates were observed during the run. The candidate events exhibit timing characteristics that are not consistent with the hypothesis of a uniform time distribution, and no evidence for a dark matter signal is claimed. These data provide the most sensitive direct detection constraints on WIMP-proton spin-dependent scattering to date, with significant sensitivity at low WIMP masses for spin-independent WIMP-nucleon scattering.

  3. Alterations in rabbit vitreal fine structure following C3F8 injection.

    PubMed

    Panessa-Warren, B; Maisel, J M; Warren, J

    1990-01-01

    This study examines the morphological and histochemical changes in the cortical vitreous of 36 rabbit eyes following C3F8 intravitreal gas injection. Eyes were examined by light microscopy (LM) using a modified cryofixation and cryosectioning technique that prevented the loss of soluble tissue moieties and permitted collagen and proteoglycan histochemistry as well as enzyme digestion with hyaluronidase. LM and scanning electron microscopy (SEM) of cryosectioned normal eyes revealed an elaborate fibrillar matrix extending 100-190 microns from the basal lamina of the retina into the vitreous proper, which seemed to be composed of collagen fibrils intimately associated or wrapped in proteoglycan. Following the full expansion of the C3F8 gas bubble in the vitreous, the cortical fibrillar meshwork was absent from the retinal surface and a dense, collagenous material accumulated in the anterior vitreous, especially between the ciliary processes and over the posterior face of the lens. At 41 days postinjection, the fibrillar matrix was reforming and the vitreal cavity was filled with fluid and numerous fibrillar-mucinous islands. These islands did not form sheets or membranes, nor did they attach to either the posterior or the anterior retinal surface. The cortical fibrillar meshwork had reformed at 61 days' recovery; however, the condensed fibrillar material against the lens and filling the spaces between the ciliary processes had not resorbed. Neither shearing of the cortical gel or fibrillar matrix nor congestion of the anterior vitreous was observed in eyes only partially filled with gas.

  4. Structure and energy difference of two isomers of He-CH3F.

    PubMed

    Higgins, Kelly J; Klemperer, William

    2005-06-22

    The intermolecular potential surface of He-CH(3)F is investigated through ab initio calculations and microwave and millimeter-wave spectroscopies. The intermolecular potential is calculated at the fourth-order Møller-Plesset level with a large basis set including bond functions. Three minimums exist, the deepest of which is at the carbon end of the C-F axis and has a depth of 46.903 cm(-1), the second deepest is in a T-shaped position relative to the C-F axis with a depth of 44.790 cm(-1), and the shallowest is at the fluorine end of the C-F axis with a depth of 30.929 cm(-1). The barrier to internal rotation of the CH(3)F subunit about its C-F axis is very low, thus leading to essentially free internal rotation and two separate sets of bound states correlating to ortho-CH(3)F (|K| = 3n) for the ground, or A, internal rotor state upon which this study focuses, and to para-CH(3)F (|K| = 3n +/- 1) for the excited, or E, internal rotor state. Bound-state calculations of the A state performed using two different techniques show the lowest-energy state to have the helium localized in the T-shaped well with an energy of -11.460 cm(-1), while two excited configurations of the A state have the helium localized either in the well at the carbon end ("linear") with an energy of -7.468 cm(-1) or in the well at the fluorine end ("antilinear") with an energy of -4.805 cm(-1). Spectroscopic observations confirm the predicted energy-level structure of the ground and first excited states. Sixteen transitions between 12 distinct energy levels have been observed, including pure rotational transitions of both the T-shaped ground state and the linear excited state, as well as rovibrational transitions between the ground state and the linear excited state. The energy difference between the T-shaped state and the linear state is measured to be 132 374.081(16) MHz. There is significant Coriolis mixing of the ground state J(K(a)K(c)) = 2(20) and the linear J(K) = 2(0) levels which aided

  5. Hydrothermal synthesis and luminescent properties of NaLa(MoO{sub 4}){sub 2}:Dy{sup 3+} phosphor

    SciTech Connect

    Li Linlin; Zi Wenwen; Li Guanghuan; Lan Shi; Ji Guijuan; Gan Shucai; Zou Haifeng; Xu Xuechun

    2012-07-15

    Pompon-like NaLa(MoO{sub 4}){sub 2}:Dy{sup 3+} phosphors have been successfully prepared via a hydrothermal method using ammonia as pH value regulator. The hydrothermal process was carried out under aqueous condition without the use of any organic solvent, surfactant, and catalyst. The experimental results demonstrate that the obtained NaLa(MoO{sub 4}){sub 2}:Dy{sup 3+} phosphor powders are single-phase scheelite structure with tetragonal symmetry. Moreover, the phosphor under the excitation of 390 and 456 nm exhibited blue emission (486 nm) and yellow emission (574 nm), corresponding to the {sup 4}F{sub 9/2}{yields}{sup 6}H{sub 15/2} transition and {sup 4}F{sub 9/2}{yields}{sup 6}H{sub 13/2} transition of Dy{sup 3+} ions, respectively. In addition, the yellow-to-blue emission intensity ratio (Y/B) can be changed with the doped concentration of Dy{sup 3+} ions. All chromaticity coordinates of the obtained NaLa(MoO{sub 4}){sub 2}:Dy{sup 3+} phosphors are located in the white-light region. The results indicate that this kind of phosphor may has potential applications in the fields of near UV-excited and blue-excited white LEDs. - Graphical abstract: It can be seen from the SEM images that a pompon-like shape was obtained with an average diameter of about 1 {mu}m, and it is composed of many nanoflakes. Highlights: Black-Right-Pointing-Pointer Pompon-like NaLa(MoO{sub 4}){sub 2}:Dy{sup 3+} phosphors have been successfully prepared via a hydrothermal method. Black-Right-Pointing-Pointer Blue emission at 486 nm and yellow emission at 574 nm were obtained from the samples. Black-Right-Pointing-Pointer The yellow-to-blue emission intensity ratio (Y/B) can be changed with the doped concentration of Dy{sup 3+} ions. Black-Right-Pointing-Pointer NaLa(MoO{sub 4}){sub 2}:Dy{sup 3+} can be efficiently excited by the blue light and the near ultraviolet light.

  6. Crystal structure of bis­(fluoro­sulfato-κO)xenon(II), Xe(SO3F)2

    PubMed Central

    Malischewski, Moritz; Seppelt, Konrad

    2015-01-01

    Thermally unstable Xe(SO3F)2 has been prepared by the reaction of XeF2 with HSO3F. Single crystals were obtained from HSO3F by slow cooling in a sealed tube. The mol­ecular structure is characterized by the Xe atom covalently bonded to two O atoms of two fluoro­sulfate tetra­hedra in an almost linear fashion [O—Xe—O = 179.13 (4)°]. The crystal packing is strongly influenced by inter­molecular van der Waals forces. PMID:26029391

  7. β-NaVOPO4sub> obtained by a low-temperature synthesis process: A new 3.3 V cathode for sodium-ion batteries

    SciTech Connect

    He, Guang; Huq, Ashfia; Manthiram, Arumugam; Kan, Wang Hay

    2016-02-02

    Vanadyl phosphates (VOPO4sub>) represent a class of attractive cathodes in lithium-ion batteries. However, the exploration of this type of materials in sodium-ion batteries is rare. Here, we report for the first time the synthesis of orthorhombic β-NaVOPO4sub> by first chemically extracting lithium from beta-LiVOPO4sub> and then inserting sodium into the obtained β-VOPO4sub> by a microwave-assisted solvothermal process with NaI, which serves both as a reducing agent and sodium source. Intermediate NaxVOPO4sub> compositions with x = 0.3, 0.5, and 0.8 have also been obtained by controlling the amount of NaI in the reaction mixture. Joint Rietveld refinement of synchrotron X-ray diffraction (XRD) and neutron diffraction confirms that the fully sodiated β-NaVOPO4sub> is isostructural with the lithium counterpart β-LiVOPO4sub>. Bond valence sum maps suggest that sodium ions possibly diffuse along the [010] direction in the lattice, similar to the ionic conduction pathway in β-LiVOPO4sub>. Although the initial discharge capacity is low due to the protons in the structure, it steadily increases with cycling with a long plateau at 3.3 V. As a result, ex situ XRD data of cycled β-VOPO4sub> and β-NaVOPO4sub> electrodes confirm the reversible reaction in sodium cells involving the V4+/V5+ redox couple.

  8. A two-step reaction scheme leading to singlet carbene species that can be detected under matrix conditions for the reaction of Zr(3F) with either CH3F or CH3CN.

    PubMed

    Torres, Ana E; Castro, Guadalupe; Pablo-Pedro, Ricardo; Colmenares, Fernando

    2014-04-30

    The results obtained from CASSCF-MRMP2 calculations are used to rationalize the singlet complexes detected under matrix-isolation conditions for the reactions of laser-ablated Zr((3)F) atoms with the CH3F and CH3CN molecules, without invoking intersystem crossings between electronic states with different multiplicities. The reaction Zr((3)F) + CH3 F evolves to the radical products ZrF· + ·CH3. This radical asymptote is degenerate to that emerging from the singlet channel of the reactants Zr((1)D) + CH3 F because they both exhibit the same electronic configuration in the metal fragment. Hence, the caged radicals obtained under cryogenic-matrix conditions can recombine through triplet and singlet paths. The recombination of the radical species along the low-multiplicity channel produces the inserted structures H3C-Zr-F and H2C=ZrHF experimentally detected. For the Zr((3)F) + CH3 CN reaction, a similar two-step reaction scheme involving the radical fragments ZrNC· + ·CH3 explains the presence of the singlet complexes H C-Zr-NC and H2 C=Zr(H)NC revealed in the IR-matrix spectra upon UV irradiation.

  9. Luminescence properties of Yb:Er:KY3F10 nanophosphor and thermal treatment effects

    NASA Astrophysics Data System (ADS)

    Gomes, Laércio; Linhares, Horácio Marconi da Silva M. D.; Ichikawa, Rodrigo Uchida; Martinez, Luis Gallego; Baldochi, Sonia Licia

    2016-04-01

    In this work, we present the spectroscopic properties of KY3F10 nanocrystals activated with erbium and codoped with ytterbium ions. The most important processes that lead to the erbium upconversion of green and red emissions of Er3+ were identified. A time-resolved luminescence spectroscopy technique was employed to measure the luminescence decays of 4S3/2 and 4F9/2 excited levels of Er3+ and to determine the upconversion processes and the luminescence efficiencies of erbium in the visible. Analysis of the luminescence kinetics in Yb:Er:KY3F10 shows a rapid upconversion (Up1) for the green emission with a time constant of 0.31 μs after pulsed laser excitation at 972 nm for as synthesized nanocrystals, which is faster than the time constant measured for the bulk crystal (23 μs). In addition, it is observed a second upconversion process (non-resonant) (Up2) responsible for the red emission (Er3+), which competes with Up1 process. However, the luminescence efficiency of the green emission (4S3/2) is observed to be very low (1.6%) for the as synthesized nanocrystal (25 °C). Nevertheless, it increases with the nanopowder heat treatment reaching an efficiency of 99% (T = 550 °C) relative to the bulk crystal. Similar luminescence behavior was observed for the 4F9/2 level (Er3+) that emits red emission. X-ray diffraction analysis of nanopowder by Rietveld method reveled that the mean crystallite size remains unchanged (8.3-12.3 nm) after thermal treatments with T ∼ 400 °C, while the 4S3/2 luminescence efficiency strongly increases to 20%. The luminescence dynamics indicates that Er3+ ions distribution plays a determinant role in the luminescence efficiency of green and red emissions of Er3+ besides also the strong influence on the upconversions processes. The observed luminescence effect is caused by the non-uniform Er3+ (and Yb3+) ions distribution due to the nanocrystal grown, which introduces a concentration gradient that increases towards the nanoparticle

  10. Characteristics and nature of the halogen-bonding interactions between CCl3F and ozone: a supermolecular and SAPT study

    NASA Astrophysics Data System (ADS)

    Esrafili, Mehdi D.; Yourdkhani, Sirous; Bahrami, Aidin

    2013-12-01

    The strength and nature of the halogen-bond interactions in CCl3F...O3 complexes were examined by means of ab initio quantum-chemical calculations and symmetry-adapted perturbation theory (SAPT). Our calculations predict a trifurcated C-Cl...O interaction for the global minimum of CCl3F...O3 complex and several local minima, differing slightly in energy, separated by very low barriers. The calculations, which include a rigorous decomposition of the interaction energies, also indicate that the interaction of CCl3F molecule with O3 is characterised by contributions from both electrostatic and dispersion energies, with the contribution of the latter being dominant. The evaluated SAPT interaction energies for the CCl3F...O3 complexes are generally in good agreement with those obtained using the supermolecule CCSD(T) method, suggesting that SAPT is a proper method to study the intermolecular interactions in these complexes.

  11. Response analysis of electron attachment rates to C3F8 and SF6 in buffer gases

    NASA Astrophysics Data System (ADS)

    Dahl, Dominik A.; Franck, Christian M.

    2013-11-01

    Electron swarm methods are applied for investigating the effects of small amounts (⩽1.5%) of a strongly electronegative sample gas in the buffer gases Ar, N2 or CO2. A pulsed Townsend method, a Monte Carlo swarm method, and a solution of the Boltzmann equation are used to determine the effective ionization rate constants of the gas mixtures. The sensitivity of the effective ionization rate constant to changes of the mixing ratio is evaluated. Our methods are benchmarked with the analysis of Ar-SF6 and N2-SF6 mixtures, and subsequently used for the analysis of gas mixtures containing C3F8. The results based on the recommended C3F8 cross sections are shown to be inconsistent with the experimental data for N2-C3F8 and CO2-C3F8 mixtures.

  12. Useful ion yields for Cameca IMS 3f and 6f SIMS: Limits on quantitative analysis

    USGS Publications Warehouse

    Hervig, R.L.; Mazdab, F.K.; Williams, Pat; Guan, Y.; Huss, G.R.; Leshin, L.A.

    2006-01-01

    The useful yields (ions detected/atom sputtered) of major and trace elements in NIST 610 glass were measured by secondary ion mass spectrometry (SIMS) using Cameca IMS 3f and 6f instruments. Useful yields of positive ions at maximum transmission range from 10-4 to 0.2 and are negatively correlated with ionization potential. We quantified the decrease in useful yields when applying energy filtering or high mass resolution techniques to remove molecular interferences. The useful yields of selected negative ions (O, S, Au) in magnetite and pyrite were also determined. These data allow the analyst to determine if a particular analysis (trace element contents or isotopic ratio) can be achieved, given the amount of sample available and the conditions of the analysis. ?? 2005 Elsevier B.V. All rights reserved.

  13. Ne matrix spectra of the sym-C6Br3F3+ radical cation

    USGS Publications Warehouse

    Bondybey, V.E.; Sears, T.J.; Miller, T.A.; Vaughn, C.; English, J.H.; Shiley, R.S.

    1981-01-01

    The electronic absorption and laser excited, wavelength resolved fluorescence spectra of the title cation have been observed in solid Ne matrix and vibrationally analysed. The vibrational structure of the excited B2A2??? state shows close similarity to the parent compound. The X2E??? ground state structure is strongly perturbed and irregular owing to a large Jahn-Teller distortion. The data are analysed in terms of a recently developed, sophisticated multimode Jahn-Teller theoretical model. We have generated the sym-C6Br3F3+ cations in solid Ne matrix and obtained their wavelength resolved emission and absorption spectra. T ground electronic X2E??? state exhibits an irregular and strongly perturbed vibrational structure, which can be successfully modeled using sophisticated multimode Jahn-Teller theory. ?? 1981.

  14. In-band pumped Ho3+:KY3F10 2 μm laser.

    PubMed

    Schellhorn, Martin; Parisi, Daniela; Veronesi, Stefano; Bolognesi, Giacomo; Eichhorn, Marc; Tonelli, Mauro

    2013-02-15

    We report the first observation to our knowledge of room-temperature continuous-wave laser operation on the (5)I(7)→(5)I(8) transition of Ho(3+) ions in a KY(3)F(10) single crystal. Using a Tm-doped silica fiber laser operating at 1938 nm as a pump source, a maximum laser power of 1.8 W was obtained at a wavelength of ~2040 nm for 27 W of absorbed pump power with a slope efficiency of 19.1% with respect to absorbed power. At low cavity output coupling, the lasing wavelength shifted to 2060.5 nm. The beam propagation factor (M(2)) was measured to be <1.06 at the maximum output power, confirming fundamental transverse-mode (TEM(00)) operation. Performing a Caird analysis, we determined resonator round-trip losses and intrinsic slope efficiency of 30% and 43.8%, respectively.

  15. Tumor induction by monoenergetic neutrons in B6C3F1 mice.

    PubMed

    Watanabe, Hiromitsu; Kashimoto, Naoki; Kajimura, Junko; Ishikawa, Masayori; Kamiya, Kenji

    2007-05-01

    This study was undertaken to investigate induction of tumors by monoenergetic neutrons in B6C3F1 mice. Individual groups of 6 week-old animals of both sexes (about 30 mice/group) were exposed to 0.5 Gy of various monoenergetic neutrons (dose rate 0.5 cGy/min) and then observed for 13 months. The incidences of tumors (mainly liver neoplasms) in non-irradiated male and female controls were 11% and 0%, respectively. In the irradiated animals, the incidences were 53%, 50%, 60% and 43% in males, and 75%, 81%, 71%, and 85% in females, after 0.18, 0.32, 0.6 and 1.0 MeV neutron exposure, respectively. There were no significant differences in the tumor induction rate among the different energy groups.

  16. Vibrational relaxation of matrix-isolated CH/sub 3/F and HCl

    SciTech Connect

    Young, L.

    1981-08-01

    Kinetic and spectroscopic studies have been performed on CH/sub 3/F and HCl as a function of host matrix and temperature. Temporally and spectrally resolved infrared fluorescence was used to monitor the populations of both the initially excited state and the lower lying levels which participate in the relaxation process. For CH/sub 3/F, relaxation from any of the levels near 3.5 ..mu.., i.e. the CH stretching fundamentals or bend overtones, occurs via rapid (< 5 ns) V ..-->.. V transfer to 2..nu../sub 3/ with subsequent relaxation of the ..nu../sub 3/ (CF stretch) manifold. Lifetimes of 2..nu../sub 3/ and ..nu../sub 3/ were determined through overtone, ..delta..V = 2, and fundamental fluorescence. These lifetimes show a dramatic dependence on host lattice, an increase of two orders of magnitude in going from Xe and Ar matrices. Lifetimes depend only weakly on temperature. The relaxation of 2..nu../sub 3/ and ..nu../sub 3/ is consistent with a model in which production of a highly rotationally excited guest via collisions with the repulsive wall of the host is the rate limiting step. For HCl, lifetimes of v = 1,2,3 have been determined. In all hosts, the relaxation is non-radiative. For a given vibrational state, v, the relaxation rate increases in the series k(Ar) < k(Kr) < k(Xe). The dependence of the relaxation rate; on v is superlinear in all matrices, the deviation from linearity increasng in the order Ar < Kr < Xe. The relaxation rates become more strongly temperature dependent with increasing vibrational excitation. The results are consistent with a mechanism in which complex formation introduces the anisotropy necessary to induce a near resonant V ..-->.. R transition in the rate limiting step.

  17. Effect of blueberry polyphenols on 3T3-F442A preadipocyte differentiation.

    PubMed

    Moghe, Shiwani S; Juma, Shanil; Imrhan, Victorine; Vijayagopal, Parakat

    2012-05-01

    Today obesity is an epidemic, and its prevalence has increased significantly over the last few decades. To avoid excessive accumulation of fat, optimum energy intake along with regular exercise is mandatory. Polyphenols present in green tea, grape seeds, orange, and grapefruit combat adipogenesis at the molecular level and also induce lipolysis. However, very little is known regarding the role of blueberry polyphenols on adipocyte differentiation. Hence we tested the dose-dependent effects of blueberry polyphenols on mouse 3T3-F442A preadipocyte differentiation and lipolysis. 3T3-F442A preadipocytes were incubated with three doses of blueberry polyphenols (150, 200, and 250 μg/mL [BB-150, BB-200, and BB-250, respectively]), and intracellular lipid content, cell proliferation, and lipolysis were assayed. Blueberry polyphenols suppressed adipocyte differentiation determined by Oil Red-O staining and AdipoRed assay. Intracellular lipid content in control (11,385.51±1,169.6 relative fluorescence units) was significantly higher (P<.05) than with the three doses of blueberry polyphenols (8336.86±503.57, 4235.67±323.17, and 3027.97±346.61, respectively). This corresponds to a reduction of 27%, 63%, and 74%, respectively. Cell proliferation was observed to be significantly higher in the control (0.744±0.035 optical density units) than with BB-150 (0.517±0.031), BB-200 (0.491±0.023), and BB-250 (0.455±0.012). However, when tested for lipolysis, there was no significant difference observed among the groups. We conclude that blueberry polyphenols may play an effective role in inhibiting adipogenesis and cell proliferation.

  18. IT3F: a web-based tool for functional analysis of transcription factors in plants.

    PubMed

    Bailey, Paul C; Dicks, Jo; Wang, Trevor L; Martin, Cathie

    2008-10-01

    A web-based tool, the Interspecies Transcription Factor Function Finder (IT3F), has been developed to display both evolutionary gene relationships and expression data for plant transcription factors, focussing primarily on the R2R3MYB gene subfamily for proof of concept. The graphical display of information allows users to make direct comparisons between structurally related genes and to identify those genes that are potentially orthologous, thereby assisting with their understanding of gene function. A key feature of the website is the provision of an interrogative phylogenetic tree that allows submission of new sequences corresponding to a transcription factor family or subfamily and maps their relative positions to the products of other genes on an 'existing' tree containing proteins encoded by Arabidopsis and rice genes, along with key proteins encoded by genes from other species that have been characterised functionally. In addition, a feature to select clusters of related sequences has been developed so that more detailed phylogenetic analysis can be performed to highlight potential orthologous and paralogous genes within related clusters. Arabidopsis genes that reside on duplicated regions of the genome are indicated on the tree, providing further information for interpreting gene function. An additional feature of the website allows a selected number of key Arabidopsis and rice microarray experiments to be visualised alongside the tree as a tabulated heat map of expression intensity values. Through this display, it is possible to observe relative expression levels across a whole gene family and the extent to which the expression of closely related genes within subgroups has altered since their ancestral divergence. The website is available at http://jicbio.nbi.ac.uk/IT3F/.

  19. Field Evaluation of Transgenic Switchgrass Plants Overexpressing PvMYB4sub> for Reduced Biomass Recalcitrance

    SciTech Connect

    Baxter, Holly L.; Poovaiah, Charleson R.; Yee, Kelsey L.; Mazarei, Mitra; Rodriguez, Miguel; Thompson, Olivia A.; Shen, Hui; Turner, Geoffrey B.; Decker, Stephen R.; Sykes, Robert W.; Chen, Fang; Davis, Mark F.; Mielenz, Jonathan R.; Davison, Brian H.; Dixon, Richard A.; Stewart, C. Neal

    2015-01-07

    High biomass yields and minimal agronomic input requirements have made switchgrass, Panicum virgatum L., a leading candidate lignocellulosic bioenergy crop. Large-scale lignocellulosic biofuel production from such crops is limited by the difficulty to deconstruct cell walls into fermentable sugars: the recalcitrance problem. In this study, we assessed the field performance of switchgrass plants overexpressing the switchgrass MYB4sub> (PvMYB4sub>) transcription factor gene. PvMYB4sub> transgenic switchgrass can have great lignin reduction, which commensurately increases sugar release and biofuel production. Our results over two growing seasons showed that one transgenic event (out of eight) had important gains in both biofuel (32% more) and biomass (63% more) at the end of the second growing season relative to non-transgenic controls. These gains represent a doubling of biofuel production per hectare, which is the highest gain reported from any field-grown modified feedstock. In contrast to this transgenic event, which had relatively low ectopic overexpression of the transgene, five of the eight transgenic events planted did not survive the first field winter. The dead plants were all high-overexpressing events that performed well in the earlier greenhouse studies. Disease susceptibility was not compromised in any transgenic events over the field experiments. These results demonstrate the power of modifying the expression of an endogenous transcription factor to improve biofuel and biomass simultaneously, and also highlight the importance of field studies for "sorting" transgenic events. In conclusion, further research is needed to develop strategies for fine-tuning temporal-spatial transgene expression in feedstocks to optimize desired phenotypes.

  20. trans-K3[TcO2(CN)4sub>

    SciTech Connect

    Chatterjee, Sayandev; Del Negro, Andrew S; Edwards, Matthew K; Twamley, Brendan; Krause, Jeanette A; Bryan, Samuel A

    2010-07-14

    The dioxotetracyanotechnetate anion, [TcO2(CN)4sub>]3-, of the title complex has octahedral symmetry. The technetium is located on a center of inversion and is bound by two oxygen atoms and four cyano ligands. The Tc=O bond distance of 1.7721 (12) Å is consistent with double bond character. The potassium cations [located on special (1/2,0,1) and general positions] reside in octahedral or tetrahedral environments; interionic K···O and K···N interactions occur in the 2.7877 (19)-2.8598 (15) Å range.

  1. Femtosecond pulse generation with an a-cut Nd:CaYAlO4sub> disordered crystal.

    PubMed

    Liu, Shan-De; Dong, Lu-Lu; Xu, Yan; Zhang, Xiao; Ren, Ting-Qi; Xu, Xiao-Dong; Peng, Yan-Dong; Zhang, Yu-Ping; Zhang, Hui-Yun; Li, De-Hua; Zhang, Bai-Tao; He, Jing-Liang

    2016-09-20

    We experimentally demonstrated a diode-pumped 587 fs ultrafast laser by using an a-cut Nd:CaYAlO4sub> crystal. Pumped by an 808 nm fiber-coupled laser diode, a stable continuous-wave mode-locked ultrafast laser was achieved with a semiconductor saturable absorber. The ultrafast pulses had a repetition rate of 75 MHz at the center wavelength of 1080.8 nm. A maximum average output power of the mode-locked laser reached 375 mW delivering a slope efficiency of 9%.

  2. Hysteretic magnetoresistance and unconventional anomalous Hall effect in the frustrated magnet TmB4sub>

    SciTech Connect

    Sunku, Sai Swaroop; Kong, Tai; Ito, Toshimitsu; Canfield, Paul C.; Shastry, B. Sriram; Sengupta, Pinaki; Panagopoulos, Christos

    2016-05-11

    We study TmB4sub>, a frustrated magnet on the Archimedean Shastry-Sutherland lattice, through magnetization and transport experiments. The lack of anisotropy in resistivity shows that TmB4 is an electronically three-dimensional system. The magnetoresistance (MR) is hysteretic at low temperature even though a corresponding hysteresis in magnetization is absent. The Hall resistivity shows unconventional anomalous Hall effect (AHE) and is linear above saturation despite a large MR. In conclusion, we propose that complex structures at magnetic domain walls may be responsible for the hysteretic MR and may also lead to the AHE.

  3. Magnetic Ordering in Sr3YCo4sub>O10+x

    SciTech Connect

    Kishida, Takayoshi; Kapetanakis, Myron D.; Yan, Jiaqiang; Sales, Brian C.; Pantelides, Sokrates T.; Pennycook, Stephen J.; Chisholm, Matthew F.

    2016-01-28

    Transition-metal oxides often exhibit complex magnetic behavior due to the strong interplay between atomic-structure, electronic and magnetic degrees of freedom. Cobaltates, especially, exhibit complex behavior because of cobalt’s ability to adopt various valence and spin state configurations. The case of the oxygen-deficient perovskite Sr3YCo4sub>O10+x (SYCO) has gained considerable attention because of persisting uncertainties about its structure and the origin of the observed room temperature ferromagnetism. Here we report a combined investigation of SYCO using aberration-corrected scanning transmission electron microscopy and density functional theory calculations.

  4. Heterogeneous Nature of Relaxation Dynamics of Room-Temperature Ionic Liquids (EMIm)2[Co(NCS)4sub>] and (BMIm)2[Co(NCS)4sub>

    SciTech Connect

    Hensel-Bielowka, Stella; Wojnarowska, Zaneta; Dzida, Marzena; Zorębski, Edward; Zorębski, Michał; Geppert-Rybczyńska, Monika; Peppel, Tim; Grzybowska, Katarzyna; Wang, Yangyang; Sokolov, Alexei P.; Paluch, Marian

    2015-08-11

    Dynamic crossover above Tg has been recognized as a characteristic feature of molecular dynamics of liquids approaching glass transition. Experimentally, it is manifested as a change in Vogel–Fulcher–Tammann dependence or a breakdown of the Stokes–Einstein and related relations. In this study, we report the exception from this rather general pattern of behavior. By means of dielectric, ultrasonic, rheological, and calorimetric methods, dynamics of two good ionic conductors (BMIm)2[Co(NCS)4sub>] and (EMIm)2[Co(NCS)4sub>] of less common stoichiometry (2:1) was studied in a very broad temperature range. However, none of the mentioned dynamic changes was observed in the entire studied temperature range. On the contrary, the single VFT and the same fractional Walden coefficient were found for conductivity and viscosity changes over 12 decades. Finally and moreover, ultrasonic studies revealed that the data at temperatures which cover the normal liquid region cannot be fitted by a single exponential decay, and the Cole–Cole function should be used instead.

  5. Morphology control of open-framework zinc phosphate Zn{sub 4}(H{sub 3}O)(NH{sub 4}){sub 3}(PO{sub 4}){sub 4} via microwave-assisted technique

    SciTech Connect

    Ding, Ling; Song, Yu; Yang, Wei; Xue, Run-Miao; Zhai, Shang-Ru; An, Qing-Da

    2013-08-15

    Open-framework zinc phosphates were synthesized by microwave-assisted technique, and it was shown that the morphology of as-prepared materials could be easily tailored by changing synthesis temperature, reaction time and pH value. During the synthesis, when the reaction temperature increases from 130 °C to 220 °C, the products transformed from hexagonal prisms to polyhedron along with the disappearance of the hexagonal prisms vertical plane. Simultaneously, both the reaction time and pH value could promote the nucleation and growth of crystal particles. More interestingly, the target products with different morphologies could be obtained by varying the usage of NaOH or NH{sub 3}·H{sub 2}O at 130 °C during the microwave synthesis process. - Graphical abstract: Zinc phosphates with variable morphologies can be obtained by simply tuning the microwave-heating temperatures. Display Omitted - Highlights: • Synthesis of open-framework Zn{sub 4} (H{sub 3}O) (NH{sub 4}){sub 3}(PO{sub 4}){sub 4} compounds employing microwave technique. • Dependence of morphology on the reaction conditions. • Morphology transformation from hexagonal prisms to polyhedron was observed.

  6. Tailoring the surface properties of LiNi0.4sub>Mn0.4sub>Co0.2O₂ by titanium substitution for improved high voltage cycling performance

    SciTech Connect

    Wolff-Goodrich, Silas; Xin, Huolin L.; Lin, Feng; Markus, Isaac M.; Nordlund, Dennis; Asta, Mark; Doeff, Marca M.

    2015-07-30

    The present research aims to provide insights into the behavior of LiNi0.4Mn0.4Co0.2O2 (NMC442) and LiNi0.4sub>Mn0.4sub>Co0.2O₂ (NMC442-Ti02) cathode materials under galvanostatic cycling to high potentials, in the context of previous work which predicted that Ti-substituted variants should deliver higher capacities and exhibit better cycling stability than the unsubstituted compounds. It is found that NMC cathodes containing Ti show equivalent capacity fading but greater specific capacity than those without Ti in the same potential range. When repeatedly charged to the same degree of delithiation, NMC cathodes containing Ti showed better capacity retention. Soft x-ray absorption spectroscopy (XAS) spectra for Mn and Co indicated increased reduction in these elements for NMC cathodes without Ti, indicating that the substitution of Ti for Co acts to suppress the formation of a high impedance rock salt phase at the surface of NMC cathode particles. The results of this study validate the adoption of a facile change to existing NMC chemistries to improve cathode capacity retention under high voltage cycling conditions.

  7. M{sup II}Ge(PO{sub 4}){sub 2} (M=Ca, Sr, Ba): Crystal structure, phase transitions and thermal expansion

    SciTech Connect

    Popa, Karin; Wallez, Gilles; Bregiroux, Damien; Loiseau, Pascal

    2011-10-15

    Three earth alkali-germanium monophosphates M{sup II}Ge(PO{sub 4}){sub 2} (M=Ca, Sr, Ba) were prepared by solid state reaction and their structures, previously unknown, studied by Rietveld analysis. BaGe(PO{sub 4}){sub 2} and high-temperature {beta}-SrGe(PO{sub 4}){sub 2} (space group C2/m, Z=2) are fully isotypic with yavapaiite, whereas CaGe(PO{sub 4}){sub 2} and low-temperature {alpha}-SrGe(PO{sub 4}){sub 2} (C2/c, Z=4) are distorted derivatives. The phase transition between the two forms is observed for the first time. The thermal expansion, resulting from several structural mechanisms, is very anisotropic. - Graphical abstract: The superstructure of SrGe(PO{sub 4}){sub 2} at room temperature ({alpha}) results from the off-centering of cation Sr{sup II}. Highlights: > Crystal structures of yavapaiite-type M{sup II}Ge(PO{sub 4}){sub 2} (M=Ca, Sr, Ba) have been solved. > Distortion and superstructure result from Ca and Sr off-centering. > A global scheme for the polymorphism of yavapaiites is proposed.

  8. Dispersion of nanocrystalline Fe3O4sub> within composite electrodes: Insights on battery-related electrochemistry

    SciTech Connect

    David C. Bock; Takeuchi, Kenneth J.; Pelliccione, Christopher J.; Zhang, Wei; Wang, Jiajun; Knehr, K. W.; Wang, Jun; Wang, Feng; West, Alan C.; Marschilok, Amy C.; Takeuchi, Esther S.

    2016-04-20

    Aggregation of nanosized materials in composite lithium-ion-battery electrodes can be a significant factor influencing electrochemical behavior. In this study, aggregation was controlled in magnetite, Fe3O4sub>, composite electrodes via oleic acid capping and subsequent dispersion in a carbon black matrix. A heat treatment process was effective in the removal of the oleic acid capping agent while preserving a high degree of Fe3O4sub> dispersion. Electrochemical testing showed that Fe3O4sub> dispersion is initially beneficial in delivering a higher functional capacity, in agreement with continuum model simulations. However, increased capacity fade upon extended cycling was observed for the dispersed Fe3O4sub> composites relative to the aggregated Fe3O4sub> composites. X-ray absorption spectroscopy measurements of electrodes post cycling indicated that the dispersed Fe3O4sub> electrodes are more oxidized in the discharged state, consistent with reduced reversibility compared with the aggregated sample. Higher charge-transfer resistance for the dispersed sample after cycling suggests increased surface-film formation on the dispersed, high-surface-area nanocrystalline Fe3O4sub> compared to the aggregated materials. Furthermore, this study provides insight into the specific effects of aggregation on electrochemistry through a multiscale view of mechanisms for magnetite composite electrodes.

  9. First-principles predicted low-energy structures of NaSc(BH{sub 4}){sub 4}

    SciTech Connect

    Tran, Huan Doan Amsler, Maximilian; Goedecker, Stefan; Botti, Silvana; Marques, Miguel A. L.

    2014-03-28

    According to previous interpretations of experimental data, sodium-scandium double-cation borohydride NaSc(BH{sub 4}){sub 4} crystallizes in the crystallographic space group Cmcm where each sodium (scandium) atom is surrounded by six scandium (sodium) atoms. A careful investigation of this phase based on ab initio calculations indicates that the structure is dynamically unstable and gives rise to an energetically and dynamically more favorable phase with C222{sub 1} symmetry and nearly identical x-ray diffraction pattern. By additionally performing extensive structural searches with the minima-hopping method we discover a class of new low-energy structures exhibiting a novel structural motif in which each sodium (scandium) atom is surrounded by four scandium (sodium) atoms arranged at the corners of either a rectangle with nearly equal sides or a tetrahedron. These new phases are all predicted to be insulators with band gaps of 7.9–8.2 eV. Finally, we estimate the influence of these structures on the hydrogen-storage performance of NaSc(BH{sub 4}){sub 4}.

  10. X-Ray Powder Diffraction Study of Synthetic Palmierite, K{sub 2}Pb(SO{sub 4}){sub 2}

    SciTech Connect

    TISSOT JR.,RALPH G.; RODRIGUEZ,MARK A.; SIPOLA,DIANA L.; VOIGT,JAMES A.

    2000-12-19

    Palmierite (K{sub 2}Pb(SO{sub 4}){sub 2}) has been prepared via a chemical synthesis method. Intensity differences were observed when X-ray powder data from the newly synthesized compound were compared to the published powder diffraction card (PDF) 29-1015 for Palmierite. Investigation of these differences indicated the possibility of preferred orientation and/or chemical inhomogeneity affecting intensities, particularly those of the basal (00{ell}) reflections. Annealing of the Palmierite was found to reduce the effects of preferred orientation. Electron microprobe analysis confirmed K:Pb:S as 2:1:2 for the annealed Palmierite powder. Subsequent least-squares refinement and Rietveld analysis of the annealed powder showed peak intensities very close to that of a calculated Palmierite pattern (based on single crystal data), yet substantially higher than many of the PDF 29-1015 published intensities. Further investigation of peak intensity variation via calculated patterns suggested that the intensity discrepancies between the annealed sample and those found in PDF 29-1015 were potentially due to chemical variation in the K{sub 2}Pb(SO{sub 4}){sub 2} composition. X-ray powder diffraction and crystal data for Palmierite are reported for the annealed sample. Palmierite is Trigonal/Hexagonal with unit cell parameters a = 5.497(1){angstrom}, c = 20.864(2) {angstrom}, space group R-3m (166), and Z = 3.

  11. Electrode Reaction Mechanism of Ag2VO2PO4sub> Cathode

    SciTech Connect

    Zhang, Ruibo; Abtew, Tesfaye A.; Quackenbush, Nicholas F.; Wangoh, Linda W.; Huie, Matthew; Brady, Alexander B.; Bock, David; Efstathiadis, Harry; Whittingham, M. Stanley; Marschilok, Amy C.; Takeuchi, Kenneth J.; Takeuchi, Esther S.; Zhang, Peihong; Piper, Louis F. J.

    2016-05-09

    In this study, the high capacity of primary lithium-ion cathode Ag2VO2PO4sub> is facilitated by both displacement and insertion reaction mechanisms. Whether the Ag extrusion (specifically, Ag reduction with Ag metal displaced from the host crystal) and V reduction are sequential or concurrent remains unclear. A microscopic description of the reaction mechanism is required for developing design rules for new multimechanism cathodes, combining both displacement and insertion reactions. However, the amorphization of Ag2VO2PO4sub> during lithiation makes the investigation of the electrode reaction mechanism difficult with conventional characterization tools. For addressing this issue, a combination of local probes of pair-distribution function and X-ray spectroscopy were used to obtain a description of the discharge reaction. We determine that the initial reaction is dominated by silver extrusion with vanadium playing a supporting role. In addition, once sufficient Ag has been displaced, the residual Ag+ in the host can no longer stabilize the host structure and V–O environment (i.e., onset of amorphization). After amorphization, silver extrusion continues but the vanadium reduction dominates the reaction. As a result, the crossover from primarily silver reduction displacement to vanadium reduction is facilitated by the amorphization that makes vanadium reduction increasingly more favorable.

  12. Nanocrystalline K{sub 2}Ca{sub 2}(SO{sub 4}){sub 3}: Eu for proton beam dosimetry

    SciTech Connect

    Bahl, Shaila; Lochab, S. P.; Pandey, A.; Aleynikov, V. E.; Molokanov, A.; Kumar, Pratik

    2012-06-05

    This paper investigates the Thermoluminescent response of nanocrystalline K{sub 2}Ca{sub 2}(SO{sub 4}){sub 3}: Eu, prepared by Co-precipitation technique to 150 MeV proton beam. The particle size was calculated to be 45 nm by the broadening of the XRD peaks using Scherrer's formula. Samples in the form of pellets were irradiated by 150 MeV proton beam with dose range of 0.1 Gy to 325 Gy. Thermoluminescence (TL) glow curves of the irradiated samples were recorded and studied. It has been found that the phosphor shows a characteristic single peak at around 420 K. The TL response is linear in the range upto 200 Gy and then saturates for higher doses. The wider linear TL response of nanocrystalline K{sub 2}Ca{sub 2}(SO{sub 4}){sub 3}: Eu and low fading makes it a superior candidate as a dosimeter to be used for detecting the doses of protons beams for its various applications in the field of space, therapy and research.

  13. The carcinogenicity of dichloroacetic acid in the male B6C3F1 mouse

    SciTech Connect

    DeAngelo, A.B.; Daniel, F.B.; Stober, J.A.; Olson, G.R. )

    1991-02-01

    Groups of male B6C3F1 mice (N = 50) were provided drinking water containing 2 g/liter sodium chloride (control) and 0.05, 0.5, and 5 g/liter dichloroacetic acid (DCA). Treatment of 30 animals in each group was carried out to 60 or 75 weeks. In a separate experiment, mice exposed to 3.5 g/liter DCA and the corresponding acetic acid control group were killed at 60 weeks. Groups of 5 mice were killed at 4, 15, 30, and 45 weeks. Time-weighted mean daily doses of 7.6, 77, 410, and 486 mg/kg/day were calculated for 0.05, 0.5, 3.5, and 5 g/liter DCA treatments. Animals exposed to 3.5 and 5 g/liter DCA had final body weights that were 87 and 83%, respectively, of the control value. Relative liver weights of 136, 230, and 351% of the control value were measured for 0.5, 3.5, and 5 g/liter, respectively. At 60 weeks mice receiving 5.0 g/liter DCA had a 90% prevalence of liver neoplasia with a mean multiplicity of 4.50 tumors/animal. Exposure to 3.5 g/liter DCA for 60 weeks resulted in a 100% tumor prevalence with an average of 4.0 tumors/animal. The prevalence of liver neoplasia and tumor multiplicity at 60 and 75 weeks in the 0.05 g/liter DCA (24.1%; 0.31 tumors/animal) and in the 0.5 g/liter group (11.1%; 0.11 tumors/animal) did not differ significantly from the control value (7.1% and 0.07 tumors/animal). No liver tumors were found in the group treated with acetic acid. Hyperplastic nodules were seen in the 3.5 (58%; 0.92/animal) and 5 g/liter DCA groups (83%; 1.27/animal). There was a significant positive dose-related trend in the age-adjusted prevalence of liver tumors. These data confirm the hepatocarcinogenicity of DCA administered in the drinking water to male B6C3F1 mice for 60 weeks.

  14. Carcinogenicity of bisphenol-A in Fischer rats and B6C3F1 mice.

    PubMed

    Huff, J

    2001-11-01

    Bisphenol-A (BP-A; 4,4'-isopropylidenediphenol) is a monomer of plastics commonly used in various consumer products, and is used as an intermediate in the manufacture of epoxy, polycarbonate, and polyester-styrene resins. A National Toxicology Program carcinogenesis bioassay of BP-A (>98% pure) was conducted by feeding diets containing 0, 1000, or 2000 ppm BP-A to groups of 50 male and 50 female Fischer (F)344 rats; 0, 1000, or 5000 ppm to groups of 50 male B6C3F1 mice; and 0, 5000, or 10,000 ppm to groups of 50 female B6C3F1 mice for 103 weeks. The mean body weights of the low- and high-dose rats and of female mice and high-dose male mice were lower than those of the controls throughout much of the study. Lower body weight gains in rats were likely caused by reduced food consumption. Survivals were comparable among groups. Regarding neoplasia, leukemias occurred at increased incidences in BP-A-dosed rats of both sexes: male, 13/50 controls vs 12/50 low-dose and 23/50 high-dose (P < 0.03); in females, the respective findings were 7/50, 13/50, and 12/50. Interstitial-cell tumors of the testes were increased in BP-A-dosed male rats: 35/49 controls vs 48/50 (P < 0.01) and 46/49 (P < 0.01); and an increasing trend was observed for mammary gland fibroadenomas in male rats (P < 0.05, 0/50 controls vs 0/50 and 4/50). In male mice, lymphomas/leukemias were increased: 2/49 controls vs 9/50 (P < 0.05) and 5/50. Multinucleated giant hepatocytes were observed in male mice (1/49 controls vs 41/49 and 41/50), whereas there was no increase of liver tumors. In their BP-A bioassay report, the National Toxicology Program concluded that there was no convincing evidence that BP-A was carcinogenic for rats or mice. However, the marginal increases in leukemias in male and female rats, along with increases in the combined incidence of lymphomas and leukemias in male mice, suggest that BP-A may be associated with increased cancers of the hematopoietic system. Increases in interstitial

  15. Acrylonitrile is a multisite carcinogen in male and female B6C3F1 mice.

    PubMed

    Ghanayem, Burhan I; Nyska, Abraham; Haseman, Joseph K; Bucher, John R

    2002-07-01

    Acrylonitrile is a heavily produced unsaturated nitrile, which is used in the production of synthetic fibers, plastics, resins, and rubber. Acrylonitrile is a multisite carcinogen in rats after exposure via gavage, drinking water, or inhalation. No carcinogenicity studies of acrylonitrile in a second animal species were available. The current studies were designed to assess the carcinogenicity of acrylonitrile in B6C3F1 mice of both sexes. Acrylonitrile was administered by gavage at 0, 2.5, 10, or 20 mg/kg/day, 5 days per week, for 2 years. Urinary thiocyanate and N-acetyl-S-(2-cyanoethyl)-L-cysteine were measured as markers of exposure to acrylonitrile. In general, there were dose-related increases in urinary thiocyanate and N-acetyl-S-(2-cyanoethyl)-L-cysteine concentrations in all dosed groups of mice and at all time points. Survival was significantly (p < 0.001) reduced in the top dose (20 mg/kg) group of male and female mice relative to controls. The incidence of forestomach papillomas and carcinomas was increased in mice of both sexes in association with an increase in forestomach epithelial hyperplasia. The incidence of Harderian gland adenomas and carcinomas was also markedly increased in the acrylonitrile-dosed groups. In female mice, the incidence of benign or malignant granulosa cell tumors (combined) in the ovary in the 10 mg/kg dose group was greater than that in the vehicle control group, but because of a lack of dose response, this was considered an equivocal finding. In addition, the incidences of atrophy and cysts in the ovary of the 10 and 20 mg/kg dose groups were significantly increased. The incidences of alveolar/bronchiolar adenoma or carcinoma (combined) were significantly increased in female mice treated with acrylonitrile at 10 mg/kg/day for 2 years. This was also considered an equivocal result. In conclusion, these studies demonstrated that acrylonitrile causes multiple carcinogenic effects after gavage administration to male and female B6

  16. Oncogenic evaluation of tetrachlorvinphos in the B6C3F1 mouse.

    PubMed

    Parker, C M; Van Gelder, G A; Chai, E Y; Gellatly, J B; Serota, D G; Voelker, R W; Vesselinovitch, S D

    1985-10-01

    Groups of 80 male and 80 female B6C3F1 mice were fed diets containing 17.5, 64, 320, 1600, 8000, and 16000 ppm tetrachlorvinphos (TCVP) for up to 103 weeks. Another group of 80 male and 80 female mice were fed TCVP (16000 ppm) that was used in a previous bioassay. One hundred-sixty male and 160 female mice served as the control group. Ten treated and 20 control mice/sex/group were killed at 6, 12, and 18 months. It was estimated that the study maximum-tolerated dose was exceeded by three- and sixfold in the 8000- and 16000-ppm dose groups, respectively. Consequently, these exposures produced excessive cytotoxicity and regenerative changes in the liver and kidneys which were associated with sex-hormonal imbalance and metabolic overload in liver. A significant decrease (15-40%) in body weight was observed in mice fed 8000 and 16000 ppm TCVP. These treated mice did not gain weight during the study. Reduced food consumption and caloric intake throughout the study were probably responsible for the increased survival and the decreased incidence of spontaneous neoplasia in mice fed 8000 and 16000 ppm TCVP. Classification of pathologic lesions observed in these high-dose groups differed among study and consulting pathologists. The consultant and Shell pathologists concluded that the liver and kidney changes were causally related to excessive toxicity which was manifest primarily by hepatocellular hyperplasia and renal tubular adenoma. Study pathologist in accordance with his classification found statistically significant increases in hepatocellular carcinoma, hepatocellular adenoma or carcinoma, and renal tubular carcinoma in male mice fed 16000 ppm TCVP. The incidence of hepatic neoplasms as evaluated by the study pathologist in female mice fed 8000 and 16000 ppm TCVP although statistically significant was of questionable biologic significance when compared with historical female controls. The only statistically significant finding observed by the consulting pathologist

  17. Sum Rules of Charm CP Asymmetries beyond the SU(3)_{F} Limit.

    PubMed

    Müller, Sarah; Nierste, Ulrich; Schacht, Stefan

    2015-12-18

    We find new sum rules between direct CP asymmetries in D meson decays with coefficients that can be determined from a global fit to branching ratio data. Our sum rules eliminate the penguin topologies P and PA, which cannot be determined from branching ratios. In this way, we can make predictions about direct CP asymmetries in the standard model without ad hoc assumptions on the sizes of penguin diagrams. We consistently include first-order SU(3)_{F} breaking in the topological amplitudes extracted from the branching ratios. By confronting our sum rules with future precise data from LHCb and Belle II, one will identify or constrain new-physics contributions to P or PA. The first sum rule correlates the CP asymmetries a_{CP}^{dir} in D^{0}→K^{+}K^{-}, D^{0}→π^{+}π^{-}, and D^{0}→π^{0}π^{0}. We study the region of the a_{CP}^{dir}(D^{0}→π^{+}π^{-})-a_{CP}^{dir}(D^{0}→π^{0}π^{0}) plane allowed by current data and find that our sum rule excludes more than half of the allowed region at 95% C.L. Our second sum rule correlates the direct CP asymmetries in D^{+}→K[over ¯]^{0}K^{+}, D_{s}^{+}→K^{0}π^{+}, and D_{s}^{+}→K^{+}π^{0}.

  18. Subchronic studies of doxylamine in B6C3F1 mice.

    PubMed

    Jackson, C D; Blackwell, B N

    1988-02-01

    Doxylamine succinate, a histamine (H1) antagonist (antihistamine), was administered as an admixture in the feed to male and female B6C3F1 mice for 14 or 90 days. Dose levels of 0, 100, 250, 500, 1000, and 2000 ppm doxylamine were administered to males and females in the 14-day study while dose levels of 0, 80, 162, 325, 750, and 1500 ppm were administered to both sexes in the 90-day study. Little toxicity was seen in the 14-day study. Final body weights in the highest dose group were reduced 4.0 and 7.3% in males and females, respectively. Treatment-related histopathological changes in the 14-day study were limited to a very low incidence of hepatic necrosis in both sexes. There was little toxicity observed in the 90-day study and no clear dose response relative to weight gain was observed. Histologically, the liver was the only organ affected by doxylamine administration. The liver lesions consisted of hepatic cell cytomegaly and/or karyomegaly which varied from mild to severe and a possible dose-related hepatic necrosis.

  19. Sum Rules of Charm C P Asymmetries beyond the SU(3 ) F Limit

    NASA Astrophysics Data System (ADS)

    Müller, Sarah; Nierste, Ulrich; Schacht, Stefan

    2015-12-01

    We find new sum rules between direct C P asymmetries in D meson decays with coefficients that can be determined from a global fit to branching ratio data. Our sum rules eliminate the penguin topologies P and P A , which cannot be determined from branching ratios. In this way, we can make predictions about direct C P asymmetries in the standard model without ad hoc assumptions on the sizes of penguin diagrams. We consistently include first-order SU(3 ) F breaking in the topological amplitudes extracted from the branching ratios. By confronting our sum rules with future precise data from LHCb and Belle II, one will identify or constrain new-physics contributions to P or P A . The first sum rule correlates the C P asymmetries aCP dir in D0→K+K-, D0→π+π- , and D0→π0π0. We study the region of the aCP dir(D0→π+π-)-aCP dir(D0→π0π0) plane allowed by current data and find that our sum rule excludes more than half of the allowed region at 95% C.L. Our second sum rule correlates the direct C P asymmetries in D+→K¯0K+, Ds+→K0π+, and Ds+→K+π0.

  20. High-pressure Raman study of liquid and crystalline CH3F up to 12 GPa

    NASA Astrophysics Data System (ADS)

    Wu, Y. H.; Shimizu, H.

    1995-01-01

    High-pressure Raman spectra of liquid and crystalline CH3F were measured up to 12 GPa at 300 K in a gasketed diamond-anvil cell. Two solid phases have been found; the transition pressures of liquid to solid phase I and phase I to phase II were determined to be 2.75 and 3.63 GPa, respectively. Among these, the solid phase I is an orientationally disordered (plastic) phase, while the solid phases II is an orientationally ordered phase. The frequency of CF stretching ν3(A1) vibration shows a large red shift with a slope dν/dP of about -2.6 cm-1/GPa in the liquid phase, and it splits into the TO and LO modes in the two solid phases. The Fermi resonances between the same symmetry vibrations of ν1(A1) and 2ν5(A1), and of ν4(E) and 2ν5(E) have been observed and their behaviors have been analyzed by the Fermi resonance theory. The pressure dependence of the CH stretching mode is compared with those of the other fluorinated methanes CH2F2, CHF2Cl, and CHF3.

  1. Luminescence of Eu and Ce in K3Ca2(SO4)3F fluoride material.

    PubMed

    Poddar, Anuradha; Gedam, S C; Dhoble, S J

    2015-09-01

    A new halophosphor K3Ca2(SO4)3F activated by Eu or Ce and K3Ca2(SO4)3F:Ce,Eu co-doped halosulfate phosphor has been synthesized by the co-precipitation method and characterized for its photoluminescence (PL). The PL emission spectra of the K3Ca2(SO4)3F:Ce phosphor show emission at 334 nm when excited at 278 nm due to 5d → 4f transition of Ce(3+) ions. In the K3Ca2(SO4)3F:Eu lattice, Eu(2+) (440 nm) as well as Eu(3+) (596 nm and 615 nm) emissions have been observed showing (5) D0 →(7) F1 and (5) D0 →(7) F2 transition of the Eu(3+) ion, which is in the blue and red region of the visible spectrum respectively. The trivalent europium ion is very useful for studying the nature of metal coordination in various systems owing to its non-degenerate emitting (5) D0 state. K3Ca2(SO4)3F:Ce,Eu is suitable for Ce(3+) → Eu(2+) → Eu(3+) energy transfer in which Ce(3+) and Eu(2+) play the role of sensitizers and Eu(2+) and Eu(3+) act as the activators. The observations presented in this paper are relevant for lamp phosphors.

  2. Subconjunctival retention of C3F8 gas increased the success rates of trabeculectomy in young people.

    PubMed

    Lu, D W; Tai, M C; Chiang, C H

    1997-06-01

    In this study, the effect of subconjunctival retention of perfluoropropane (C3F8) gas on trabeculectomy was evaluated to determine if this maneuver would increase the success rate of the surgery. Thirty-two patients (under 35 years old) with a diagnosis of primary open-angle glaucoma or steroid-induced glaucoma were randomized into two groups to receive trabeculectomy: Group A (trabeculectomy alone, 16 eyes) and Group B (trabeculectomy with subconjunctival retention of 0.5 mL pure C3F8 gas, 16 eyes). The results showed that the typical appearance of a subconjunctivally retained C3F8 filtering bleb is highly distended in the first two weeks after surgery, followed by flattening and diffusing gradually. The average retention time of C3F8 gas within the subconjunctival space is 28 +/- 6 days. A higher success rate was noted in Group B than in Group A (94% versus 50%, p = 0.016) at a mean follow-up time of 12 months. However, there were no differences in complication rates and results of final visual acuity between the two groups (both groups had two patients lose more than two lines of vision, p = 1.0). Our study suggests that subconjunctival retention of C3F8 gas increases the success rate of trabeculectomy in young people in the intermediate-term (12 months) follow-up period.

  3. Crystal structure, thermally stability and photoluminescence properties of novel Sr{sub 10}(PO{sub 4}){sub 6}O:Eu{sup 2+} phosphors

    SciTech Connect

    Guo, Qingfeng; Liao, Libing Mei, Lefu; Liu, Haikun

    2015-03-15

    A series of novel luminescent phosphors Sr{sub 10}(PO{sub 4}){sub 6}O:Eu{sup 2+} with apatite structure were synthesized via a high temperature solid-state reaction. The phase structure, photoluminescence (PL) properties, the PL thermal stability, as well as the fluorescence decay curves of the samples were investigated to characterize the resulting samples, and the selected Sr{sub 9.97}(PO{sub 4}){sub 6}O:0.03Eu{sup 2+} phosphor exhibits strong thermal quenching resistance, retaining the luminance of 88.73% at 150 °C. The quenching concentration of Eu{sup 2+} in Sr{sub 10}(PO{sub 4}){sub 6}O was about 0.03 attributing to the dipole–quadrupole interaction. The Sr{sub 10}(PO{sub 4}){sub 6}O:Eu{sup 2+} phosphor exhibited a broad-band blue emission at 439 nm upon excitation at 346 nm. The results indicate that Sr{sub 10}(PO{sub 4}){sub 6}O:Eu{sup 2+} phosphors have potential applications as near UV-convertible phosphors for white-light UV LEDs. - Graphical abstract: Sr{sub 10}(PO{sub 4}){sub 6}O:Eu{sup 2+} phosphors have potential applications as near UV-convertible phosphors for white-light UV LEDs. - Highlights: • Sr{sub 9.97}(PO{sub 4}){sub 6}O:0.03Eu{sup 2+} phosphor exhibits strong thermal quenching resistance. • Two different Eu{sup 2+} emission centers exists in Sr{sub 10}(PO{sub 4}){sub 6}O. • The activation energy was also estimated for the Eu{sup 2+} luminescence center.

  4. Photoluminescence performance of thulium doped Li{sub 4}SrCa(SiO{sub 4}){sub 2} under irradiation of ultraviolet and vacuum ultraviolet lights

    SciTech Connect

    Wang, Zhaofeng; Li, Yezhou; Liu, Xiong; Wei, Xingmin; Chen, Yueling; Zhou, Fei; Wang, Yuhua

    2014-11-15

    Highlights: • A novel blue-emitting phosphor Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} was reported. • Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} exhibited excellent thermal and irradiation stability. • Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} was found to possess high color purity. - Abstract: In this work, we synthesized Tm{sup 3+} doped Li{sub 4}SrCa(SiO{sub 4}){sub 2} phosphors and investigated their photoluminescence properties under the excitation of ultraviolet and vacuum ultraviolet lights. The crystal structure analysis and variation of cell parameters confirm that Tm{sup 3+} ions have been successfully doped in the structure of Li{sub 4}SrCa(SiO{sub 4}){sub 2} host by occupying the sites of Ca{sup 2+} with the coordination number of 6. The luminescence results suggest that Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} is a good blue-emitting phosphor when excited by ultraviolet and vacuum ultraviolet irradiations. In addition, it is observed that there is nearly no degradation for Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} after undergoing thermal and irradiation treatments. Possible mechanisms for the luminescence processes are proposed on the basis of the discussion of excitation and emission spectra. In particular, the emission color of Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} by excitation of 147 and 172 nm irradiations is very close to the standard blue color, suggesting that it could be potentially applied in plasma display panels and mercury-free fluorescence lamps.

  5. Etude des transitions de phases dans les systèmes K 3MO 3F 3- A3MO 3F 3( A= Na, Rb; M= Mo, W)

    NASA Astrophysics Data System (ADS)

    Fouad, M.; Chaminade, J. P.; Ravez, J.; Sadel, A.

    1996-06-01

    RésuméX-ray diffraction, differential thermal analysis, polarized light microscopy, and dielectric measurements have been used to study phase transitions and solid solutions in the K3MO3F3-A3MO3F3(A= Rb, Na;M= Mo, W) systems. K3MO3F3-Na3MO3F3(M= Mo, W) systems show two solid solutions; the first (SSI) nearx= 0 (K3-xNaxMO3F3) involves only one transition atTCwhich is practically independent of composition. The sharp transition atT1(3F3retains cubic symmetry down to 80 K. Rb3MO3F3-K3MO3F3systems show three solid solutions. The SS1 and SS3 exist close to the rubidium and potassium extremes of the binary lines. The pure phases display transitions atT1andTC. For compositions far fromy= 0 ory= 3 (Rb3-yKyMO3F3),TCdecreases andT1decreases abruptly and for SS1 becomes indetectable. The solid solution SS2 (neary= 1) has cubic symmetry down to 80 K forM= W, and a cubic-noncubic transition at low temperature forM= Mo. In any case, the phase transitions are of first order, reversible, and improper character. The transition atTCis ferroelectric, ferroelastic-paraelectric, prototype. The extent of each solid solution depends on the ratio of alcaline cations present in the 6- and 12-fold coordination sites of the perovskite structure. Des techniques expérimentales variées ont permis d'étudier les transitions de phases au sein des différentes solutions solides obtenues dans les systèmes K3MO3F3-A3MO3F3(A= Na, Rb;M= Mo, W): diffraction des rayons X, analyse thermique différentielle, microscopie optique en lumière polarisée. Les systèmes K3MO3F3-Na3MO3F3(M= Mo, W) présentent deux solutions solides. La première (SS1) au voisinage dex= 0 (K3-xNaxMO3F3) ne présente qu'une seule transition àTCqui reste pratiquement constante lorsque la composition varie; la transition qui était franche pourx= 0 àT1

  6. Investigation of the physical properties of the tetragonal CeMAl4sub>Si2 (M = Rh, Ir, Pt) compounds

    SciTech Connect

    Ghimire, N. J.; Ronning, F.; Williams, D. J.; Scott, B. L.; Luo, Yongkang; Thompson, J. D.; Bauer, E. D.

    2014-12-15

    The synthesis, crystal structure and physical properties studied by means of x-ray diffraction, magnetic, thermal and transport measurements of CeMAl4sub>Si2 (M = Rh, Ir, Pt) are reported, along with the electronic structure calculations for LaMAl4sub>Si2 (M = Rh, Ir, Pt). These materials adopt a tetragonal crystal structure (space group P4/mmm) comprised of BaAl4sub> blocks, separated by MAl2 units, stacked along the c-axis. Both CeRhAl4sub>Si2 and CeIrAl4sub>Si2 order antiferromagnetically below TN1 = 14 and 16 K, respectively, and undergo a second antiferromagnetic transitition at lower temperature (TN2 = 9 and 14 K, respectively). CePtAl4sub>Si2 orders ferromagnetically below TC = 3 K with an ordered moment of μsat = 0.8 μB for a magnetic field applied perpendicular to the c-axis. Electronic structure calculations reveal quasi-2D character of the Fermi surface.

  7. Controlled synthesis, characterization and photoluminescence property of olive-like tetragonal α-Nd{sub 2}(MoO{sub 4}){sub 3}

    SciTech Connect

    Zhang, Youjin; Zheng, Ao; Yang, Xiaozhi; He, Hongmei; Fan, Yun

    2012-09-15

    Highlights: ► The olive-like tetragonal α-Nd{sub 2}(MoO{sub 4}){sub 3} was gained with EDTA assisted hydrothermal method. ► The product was characterized by XRD, XPS, FTIR, FESEM, and PL. ► The possible formation mechanism for olive-like α-Nd{sub 2}(MoO{sub 4}){sub 3} was proposed. ► The PL in visible region of the olive-like α-Nd{sub 2}(MoO{sub 4}){sub 3} was studied. -- Abstract: The olive-like tetragonal α-Nd{sub 2}(MoO{sub 4}){sub 3} was obtained by a convenient and facile complex agent assisted hydrothermal method. The product was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FESEM) and photoluminescence (PL). The possible formation mechanism of the olive-like α-Nd{sub 2}(MoO{sub 4}){sub 3} was proposed. The photoluminescence property in visible region of the olive-like tetragonal α-Nd{sub 2}(MoO{sub 4}){sub 3} was studied.

  8. Highly selective and precisely controlled aluminum etching by Ar/HBr/CH3F/O2 gas chemistry

    NASA Astrophysics Data System (ADS)

    Suzuki, Eiji; Ohtake, Hiroto; Ohsawa, Yusuke; Kumar, Kaushik; Sasaki, Masaru

    2014-01-01

    Highly selective and precisely controlled aluminum etching was investigated by using plasma with a new Ar/HBr/CH3F/O2 gas chemistry. Generally, an aluminum surface is oxidized, leading to difficulties in the precise control of nm/min-level aluminum etching with a high selectivity to SiO2 of more than 10. The new gas chemistry enabled precise aluminum etching with a high selectivity to oxide of 10 and a low etching rate of 10 nm/min. In this gas chemistry, the aluminum surface remained oxidized by oxygen during etching and the oxidized surface was reduced by CH3F. The oxidized aluminum surface was etched by radicals from CH3F and the etching rate was decreased by HBr.

  9. New measurement of the {sup 68}Zn(4{sub 1}{sup +}) g factor combined with a reanalysis of previous data

    SciTech Connect

    Moschner, K.; Bernards, C.; Bettermann, L.; Speidel, K.-H.; Leske, J.; Bauer, C.; Moeller, T.; Honma, M.; Maier-Komor, P.; Muecher, D.

    2010-07-15

    We have remeasured and have redetermined the g factor for the 4{sub 1}{sup +} state in {sup 68}Zn following inconsistencies between earlier measurements and a recent result. We have reanalyzed several former measurements by applying an alternative analysis procedure, which allows for determining the precession effect separately for each gamma detector implying less uncertainties in the background subtraction for the relevant spectra. In addition, all measured g-factor and B(E2) data for the first 2{sup +} and 4{sup +} states in all stable even-A Zn isotopes and the radioactive {sup 62}Zn, are compared with new large-scale shell model calculations based on the most advanced effective interaction in the fpg-shell model space.

  10. Characterization of LiMn2O4sub> cathodes by electrochemical strain microscopy

    SciTech Connect

    Alikin, D. O.; Ievlev, A. V.; Luchkin, S. Yu.; Turygin, A. P.; Shur, V. Ya.; Kalinin, S. V.; Kholkin, A. L.

    2016-03-15

    Electrochemical strain microscopy (ESM) is a scanning probe microscopy(SPM) method in which the local electrodiffusion is probed via application of AC voltage to the SPM tip and registration of resulting electrochemical strain. In this study, we implemented ESM to measure local strain in bulk LiMn2O4sub> cathodes of a commercial Li-battery in different states of charge to investigate distribution of Li-ion mobility and concentration. Ramped AC ESM imaging and voltage spectroscopy were used to find the most reliable regime of measurements allowing separating and diminishing different contributions to ESM. This is not a trivial task due to complex geometry of the sample and various obstacles resulting in less predictable contributions of different origins into ESM response: electrostatic tip–surface interactions, charge injection, electrostriction, and flexoelectricity. Finally, understanding and control of these contributions is an important step towards quantitative interpretation of ESM data.

  11. Enhanced Thermoelectric Properties of Cu2ZnSnSe4sub> with Ga-doping

    SciTech Connect

    Wei, Kaya; Beauchemin, Laura; Wang, Hsin; Porter, Wallace D.; Martin, Joshua; Nolas, George S.

    2015-08-10

    Gallium doped Cu2ZnSnSe4sub> quaternary chalcogenides with and without excess Cu were synthesized by elemental reaction and densified using hot pressing in order to investigate their high temperature thermoelectric properties. The resistivity, , and Seebeck coefficient, S, for these materials decrease with increased Ga-doping while both mobility and effective mass increase with Ga doping. The power factor (S2/ρ) therefore increases with Ga-doping. The highest thermoelectric figure of merit (ZT = 0.39 at 700 K) was obtained for the composition that had the lowest thermal conductivity. Our results suggest an approach to achieving optimized thermoelectric properties and are part of the continuing effort to explore different quaternary chalcogenide compositions and structure types, as this class of materials continues to be of interest for thermoelectrics applications.

  12. The role of Sb in solar cell material Cu 2 ZnSnS 4sub>

    SciTech Connect

    Zhang, Xiaoli; Han, Miaomiao; Zeng, Zhi; Duan, Yuhua

    2017-01-01

    In this study, based on first-principles calculations we report a possible mechanism of the efficiency improvement of the Sb-doped Cu2ZnSnS4sub> (CZTS) solar cells from the Sb-related defect point of view. Different from Sb in CuInSe2 which substituted the Cu atomic site and acted as group-13 elements on the Cu-poor growth condition, we find out that Sb prefers to substitute Sn atomic site and acts as group-14 elements on the Cu-poor growth condition in CZTS. At low Sb concentration, SbSn produces a deep defect level which is detrimental for the solar cell application. At high Sb concentration, Sb 5s states form an isolated half-filled intermediate band at 0.5 eV above the valence band maximum which will increase the photocurrent as well as the solar cell efficiency.

  13. Ionic liquid assisted microwave synthesis route towards color-tunable luminescence of lanthanide- doped BiPO4sub>

    SciTech Connect

    Cybinska, Joanna; Lorbeer, Chantal; Mudring, Anja -Verena

    2015-07-08

    Ln3+-doped (Ln=Sm, Eu, Tb, Dy) nanoparticles of BiPO4sub> with a particle size below 10 nm were synthesized in a straightforward manner from the appropriate mixture of the respective metal acetates and the task-specific ionic liquids choline or butylammonium dihydrogen-phosphate by conversion in a laboratory microwave (120 °C, 10 min). The ionic liquid acts not only as a solvent and microwave susceptor, but also as the reaction partner and nanoparticle stabilizer. The materials were thoroughly characterized not only with respect to their optical properties but also by PXRD, FT-IR, TEM techniques. Furthermore, depending on the lanthanide, the nanomaterial shows intense luminescence of different colors such as: orange (Sm3+), red (Eu3+), green (Tb3+) or even white (Dy3+).

  14. Beam test evaluation of electromagnetic calorimeter modules made from proton-damaged PbWO4sub> crystals

    SciTech Connect

    Adams, T.; Adzic, P.; Ahuja, S.; Anderson, D.; Andrews, M. B.; Antropov, I.; Antunovic, Z.; Arcidiacono, R.; Arenton, M. W.; Argirò, S.; Askew, A.; Attikis, A.; Auffray, E.; Baccaro, S.; Baffioni, S.; Bailleux, D.; Baillon, P.; Barney, D.; Barone, L.; Bartoloni, A.; Bartosik, N.; Becheva, E.; Bein, S.; Beirāo Da Cruz E Silva, C.; Bell, K. W.; Benaglia, A.; Bendavid, J.; Berry, D.; Besancon, M.; Betev, B.; Bialas, W.; Bianchini, L.; Biino, C.; Bitioukov, S.; Bornheim, A.; Brianza, L.; Brinkerhoff, A.; Brown, R. M.; Brummitt, A.; Busson, P.; Candelise, V.; Montoya, C. A. Carrillo; Cartiglia, N.; Cavallari, F.; Chang, Y. W.; Chen, K. F.; Chevenier, G.; Chipaux, R.; Clement, E.; Cockerill, D. J. A.; Corpe, L.; Couderc, F.; Courbon, B.; Cox, B.; Cucciati, G.; Cussans, D.; D'imperio, G.; Calafiori, D. R. Da Silva Di; Dafinei, I.; Daguin, J.; Daskalakis, G.; Mendes, A. D. Tinoco; Guio, F. De; Degano, A.; Dejardin, M.; Re, D. Del; Ricca, G. Della; Denegri, D.; Depasse, P.; Dev, N.; Deyrail, D.; Marco, E. Di; Diamond, B.; Diemoz, M.; Dissertori, G.; Dittmar, M.; Djambazov, L.; Doan, T. H.; Dobrzynski, L.; Dolgopolov, A.; Donegà, M.; Dordevic, M.; Dröge, M.; Durkin, T.; Dutta, D.; Mamouni, H. El; Elliott-Peisert, A.; Elmalis, E.; Fabbro, B.; Fasanella, G.; Faure, J.; Fay, J.; Fedorov, A.; Ferri, F.; Francis, B.; Frank, N.; Franzoni, G.; Funk, W.; Ganjour, S.; Gascon, S.; Gastal, M.; Geerebaert, Y.; Gelli, S.; Gerosa, R.; Ghezzi, A.; Giakoumopoulou, V. A.; Givernaud, A.; Gninenko, S.; Godinovic, N.; Goeckner-Wald, N.; Golubev, N.; Govoni, P.; Gras, P.; Guilloux, F.; Haller, C.; de Monchenault, G. Hamel; Hansen, M.; Hansen, P.; Hardenbrook, J.; Heath, H. F.; Hill, J.; Hirosky, R.; Hobson, P. R.; Holme, O.; Honma, A.; Hou, W. -S.; Hsiung, Y.; Iiyama, Y.; Ille, B.; Ingram, Q.; Jain, S.; Jarry, P.; Jessop, C.; Jovanovic, D.; Kachanov, V.; Kalafut, S.; Kao, K. Y.; Kellams, N.; Kesisoglou, S.; Khatiwada, A.; Konoplyannikov, A.; Konstantinov, D.; Korzhik, M.; Kovac, M.; Kubota, Y.; Kucher, I.; Kumar, A.; Kumar, A.; Kuo, C.; Kyberd, P.; Kyriakis, A.; Latyshev, G.; Lecoq, P.; Ledovskoy, A.; Lei, Y. J.; Lelas, D.; Lethuillier, M.; Li, H.; Lin, W.; Liu, Y. F.; Locci, E.; Longo, E.; Loukas, D.; Lu, R. -S.; Lucchini, M. T.; Lustermann, W.; Mackay, C. K.; Magniette, F.; Malcles, J.; Malhotra, S.; Mandjavidze, I.; Maravin, Y.; Margaroli, F.; Marinelli, N.; Marini, A. C.; Martelli, A.; Marzocchi, B.; Massironi, A.; Matveev, V.; Mechinsky, V.; Meng, F.; Meridiani, P.; Micheli, F.; Milosevic, J.; Mousa, J.; Musella, P.; Nessi-Tedaldi, F.; Neu, C.; Newman, H.; Nicolaou, C.; Nourbakhsh, S.; Obertino, M. M.; Organtini, G.; Orimoto, T.; Paganini, P.; Paganis, E.; Paganoni, M.; Pandolfi, F.; Panov, V.; Paramatti, R.; Parracho, P.; Pastrone, N.; Paulini, M.; Pauss, F.; Pauwels, K.; Pellegrino, F.; Pena, C.; Perniè, L.; Peruzzi, M.; Petrakou, E.; Petyt, D.; Pigazzini, S.; Piroué, P.; Planer, M.; Plestina, R.; Polic, D.; Prosper, H.; Ptochos, F.; Puljak, I.; Quittnat, M.; Ragazzi, S.; Rahatlou, S.; Rander, J.; Ranjan, K.; Silva, J. Rasteiro Da; Razis, P. A.; Romanteau, T.; Rosowsky, A.; Rovelli, C.; Rusack, R.; Salerno, R.; Santanastasio, F.; Santra, A.; Schönenberger, M.; Seez, C.; Sharma, V.; Shepherd-Themistocleous, C.; Shiu, J. G.; Shivpuri, R. K.; Singovsky, A.; Sinthuprasith, T.; Sirois, Y.; Smiljkovic, N.; Soffi, L.; Sun, M.; Symonds, P.; de Fatis, T. Tabarelli; Tambe, N.; Tarasov, I.; Taroni, S.; Lima, R. Teixeira De; Thea, A.; Theofilatos, K.; Thiant, F.; Titov, M.; Torbet, M.; Trapani, P. P.; Tropea, P.; Tsai, J. f.; Tsirou, A.; Turkewitz, J.; Tyurin, N.; Tzeng, Y. M.; Uzunian, A.; Valls, N.; Varela, J.; Veeraraghavan, V.; Verdini, P. G.; Vichoudis, P.; Vlassov, E.; Wang, J.; Wang, T.; Weinberg, M.; Wolfe, E.; Wood, J.; Zabi, A.; Zahid, S.; Zelepoukine, S.; Zghiche, A.; Zhang, L.; Zhu, K.; Zhu, R.; Zuyeuski, R.

    2016-04-11

    The performance of electromagnetic calorimeter modules made of proton-irradiated PbWO4sub> crystals has been studied in beam tests. The modules, similar to those used in the Endcaps of the CMS electromagnetic calorimeter (ECAL), were formed from 5×5 matrices of PbWO4sub> crystals, which had previously been exposed to 24 GeV protons up to integrated fluences between 2.1 × 1013 and 1.3 × 1014 cm–2. These correspond to the predicted charged-hadron fluences in the ECAL Endcaps at pseudorapidity η = 2.6 after about 500 fb–1 and 3000 fb–1 respectively, corresponding to the end of the LHC and High Luminosity LHC operation periods. The irradiated crystals have a lower light transmission for wavelengths corresponding to the scintillation light, and a correspondingly reduced light output. A comparison with four crystals irradiated in situ in CMS showed no significant rate dependence of hadron-induced damage. A degradation of the energy resolution and a non-linear response to electron showers are observed in damaged crystals. Direct measurements of the light output from the crystals show the amplitude decreasing and pulse becoming faster as the fluence increases. The latter is interpreted, through comparison with simulation, as a side-effect of the degradation in light transmission. In conclusion, the experimental results obtained can be used to estimate the long term performance of the CMS ECAL.

  15. Association between X-linked mixed deafness and mutations in the POU domain gene POU3F4.

    PubMed

    de Kok, Y J; van der Maarel, S M; Bitner-Glindzicz, M; Huber, I; Monaco, A P; Malcolm, S; Pembrey, M E; Ropers, H H; Cremers, F P

    1995-02-03

    Deafness with fixation of the stapes (DFN3) is the most frequent X-linked form of hearing impairment. The underlying gene has been localized to a 500-kilobase segment of the Xq21 band. Here, it is reported that a candidate gene for this disorder, Brain 4 (POU3F4), which encodes a transcription factor with a POU domain, maps to the same interval. In five unrelated patients with DFN3 but not in 50 normal controls, small mutations were found that result in truncation of the predicted protein or in nonconservative amino acid substitutions. These findings indicate that POU3F4 mutations are a molecular cause of DFN3.

  16. Toxicokinetics of acrylamide and glycidamide in B6C3F{sub 1} mice

    SciTech Connect

    Doerge, Daniel R. . E-mail: ddoerge@nctr.fda.gov; Young, John F.; McDaniel, L. Patrice; Twaddle, Nathan C.; Churchwell, Mona I.

    2005-02-01

    Acrylamide (AA) is a widely studied industrial chemical that is neurotoxic, mutagenic to somatic and germ cells, and carcinogenic in rodents. The recent discovery of AA at ppm levels in a wide variety of commonly consumed foods has energized research efforts worldwide to define toxic mechanisms, particularly toxicokinetics and bioavailability. This study compares the toxicokinetics of AA and its epoxide metabolite glycidamide (GA) in serum and tissues of male and female B6C3F1 mice following acute dosing by intravenous, gavage, and dietary routes at 0.1 mg/kg AA or intravenous and gavage dosing with an equimolar amount of GA. AA was rapidly absorbed from oral dosing, was widely distributed to tissues, was efficiently converted to GA, and increased levels of GA-DNA adducts were observed in liver after complete elimination from serum. GA dosing also resulted in rapid absorption, wide distribution to tissues, and produced liver DNA adduct levels that were approximately 40% higher than those from an equimolar dose of AA. While oral administration was found to attenuate AA bioavailability to 23% from the diet and to 32-52% from aqueous gavage, a first-pass effect or other kinetic change resulted in higher relative internal exposure to GA when compared to the intravenous route. A similar effect on relative GA exposure was also evident as the administered dose was reduced, which suggests that as dosing rate decreases, the conversion of AA to GA is more efficient. These findings are critical to the assessment of genotoxicity of AA at low doses in the food supply, which appears to depend on total exposure to GA.

  17. Kinetics of Arsenic Methylation by Freshly Isolated B6C3F1 Mouse Hepatocytes

    SciTech Connect

    Kedderis, Gregory L.; Elmore, Amy R.; Crecelius, Eric A.; Yager, Janice W.; Goldsworthy, Thomas L.

    2006-06-10

    The toxic and carcinogenic effects of arsenic may be mediated by both inorganic and methylated arsenic species. The methylation of arsenicIII takes place via sequential oxidative methylation and reduction steps to form monomethylarsenic (MMA) and dimethylarsenic (DMA) species. The kinetics of arsenic methylation were determined in freshly isolated hepatocytes from male B6C3F1 mice. Hepatocytes (>90% viability) were isolated by collagenase perfusion and suspended in Williams Medium E with various concentrations of arsenicIII (sodium m-arsenite). Aliquots of the cell suspension were lysed with 1.0% Triton X-100 and analyzed for arsenic species by hydride generation-atomic absorption spectrometry. The formation of MMAIII from sodium arsenite (1 ?M) was linear with respect to time for >90 min. DMAIII formation did not become significant until 60 min. MMAV and DMAV were not consistently observed in the incubations. These results suggest that the reduction of MMAV to MMAIII is rapid relative to the methylation rate since MMAV was not observed as a major product of arsenicIII metabolism in mouse hepatocytes. Metabolism of arsenicV was not observed in mouse hepatocytes, consistent with inhibition of arsenicV active cellular uptake by phosphate in the medium. The formation of MMAIII increased with increasing arsenicIII concentrations up to approximately 2 ?M and declined thereafter. The concentration dependence is consistent with a saturable methylation reaction accompanied by substrate inhibition of the reaction by arsenicIII. Kinetic analysis of the data suggested an apparent KM of approximately 3.6 ?M arsenicIII, an apparent Vmax of approximately 38.9 ?g MMAIII formed/L/hr/million cells, and an apparent KI of approximately 1.3 ?M arsenicIII. The results of this study can be used in the physiologically based pharmacokinetic model for arsenic disposition in mice to predict the concentration of MMAIII in liver and other tissues.

  18. Syntheses, crystal structures and vibrational spectra of KLn(SO{sub 4}){sub 2}.H{sub 2}O (Ln=La, Nd, Sm, Eu, Gd, Dy)

    SciTech Connect

    Kazmierczak, Karolina; Hoeppe, Henning A.

    2010-09-15

    The potassium lanthanide double sulphates KLn(SO{sub 4}){sub 2}.H{sub 2}O (Ln=La, Nd, Sm, Eu, Gd, Dy) were obtained by evaporation of aqueous reaction mixtures of rare earth (III) sulphates and potassium thiocyanate at 298 K. X-ray single-crystal investigations show that KLn(SO{sub 4}){sub 2}.H{sub 2}O (Ln=Nd, Sm, Eu, Gd, Dy) crystallise monoclinically (Ln=Sm: P2{sub 1}/c, Z=4, a=10.047(1), b=8.4555(1), c=10.349(1) A, wR2=0.060, R1=0.024, 945 reflections, 125 parameters) while KLa(SO{sub 4}){sub 2}.H{sub 2}O adopts space group P3{sub 2}21 (Z=3, a=7.1490(5), c=13.2439(12) A, wR2=0.038, R1=0.017, 695 reflections, 65 parameters). The coordination environment of the lanthanide ions in KLn(SO{sub 4}){sub 2}.H{sub 2}O is different in the case of the Nd/Sm/Gd and the Eu/Dy compounds, respectively. In the first case the Ln atoms are nine-fold coordinated in contrast to the latter where the Ln ions are eight-fold coordinated by oxygen atoms. The vibrational spectra of KLn(SO{sub 4}){sub 2}.H{sub 2}O and the UV-vis reflection spectra of KEu(SO{sub 4}){sub 2}.H{sub 2}O and KNd(SO{sub 4}){sub 2}.H{sub 2}O are also reported. - Graphical abstract: The lanthanide potassium double sulphates exhibit an unexpected change in the coordination mode by a simple rotation of sulphate tetrahedron 2.

  19. Synthesis, structural and spectroscopic properties of acentric triple molybdate Cs{sub 2}NaBi(MoO{sub 4}){sub 3}

    SciTech Connect

    Savina, A.A.; Atuchin, V.V.; Solodovnikov, S.F.; Solodovnikova, Z.A.; Krylov, A.S.; Maximovskiy, E.A.; Molokeev, M.S.; Oreshonkov, A.S; Pugachev, A.M.; and others

    2015-05-15

    New ternary molybdate Cs{sub 2}NaBi(MoO{sub 4}){sub 3} is synthesized in the system Na{sub 2}MoO{sub 4}–Cs{sub 2}MoO{sub 4}–Bi{sub 2}(MoO{sub 4}){sub 3}. The structure of Cs{sub 2}NaBi(MoO{sub 4}){sub 3} of a new type is determined in noncentrosymmetric space group R3c, a=10.6435(2), c=40.9524(7) Å, V=4017.71(13) Å{sup 3}, Z=12 in anisotropic approximation for all atoms taking into account racemic twinning. The structure is completely ordered, Mo atoms are tetrahedrally coordinated, Bi(1) and Bi(2) atoms are in octahedra, and Na(1) and Na(2) atoms have a distorted trigonal prismatic coordination. The Cs(1) and Cs(2) atoms are in the framework cavities with coordination numbers 12 and 10, respectively. No phase transitions were found in Cs{sub 2}NaBi(MoO{sub 4}){sub 3} up to the melting point at 826 K. The compound shows an SHG signal, I{sub 2w}/I{sub 2w}(SiO{sub 2})=5 estimated by the powder method. The vibrational properties are evaluated by Raman spectroscopy, and 26 narrow lines are measured. - Graphical abstract: - Highlights: • The crystal structure of Cs{sub 2}NaBi(MoO{sub 4}){sub 3} is defined. • The molybdate Cs{sub 2}NaBi(MoO{sub 4}){sub 3} is stable up to melting point at 826 K. • Vibrational properties of Cs{sub 2}NaBi(MoO{sub 4}){sub 3} are evaluated by Raman spectroscopy.

  20. 29 CFR 780.105 - “Primary” and “secondary” agriculture under section 3(f).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false âPrimaryâ and âsecondaryâ agriculture under section 3(f... EXEMPTIONS APPLICABLE TO AGRICULTURE, PROCESSING OF AGRICULTURAL COMMODITIES, AND RELATED SUBJECTS UNDER THE FAIR LABOR STANDARDS ACT General Scope of Agriculture Introductory § 780.105 “Primary” and...

  1. 29 CFR 780.105 - “Primary” and “secondary” agriculture under section 3(f).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false âPrimaryâ and âsecondaryâ agriculture under section 3(f... EXEMPTIONS APPLICABLE TO AGRICULTURE, PROCESSING OF AGRICULTURAL COMMODITIES, AND RELATED SUBJECTS UNDER THE FAIR LABOR STANDARDS ACT General Scope of Agriculture Introductory § 780.105 “Primary” and...

  2. 29 CFR 780.105 - “Primary” and “secondary” agriculture under section 3(f).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false âPrimaryâ and âsecondaryâ agriculture under section 3(f... EXEMPTIONS APPLICABLE TO AGRICULTURE, PROCESSING OF AGRICULTURAL COMMODITIES, AND RELATED SUBJECTS UNDER THE FAIR LABOR STANDARDS ACT General Scope of Agriculture Introductory § 780.105 “Primary” and...

  3. 29 CFR 780.105 - “Primary” and “secondary” agriculture under section 3(f).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false âPrimaryâ and âsecondaryâ agriculture under section 3(f... EXEMPTIONS APPLICABLE TO AGRICULTURE, PROCESSING OF AGRICULTURAL COMMODITIES, AND RELATED SUBJECTS UNDER THE FAIR LABOR STANDARDS ACT General Scope of Agriculture Introductory § 780.105 “Primary” and...

  4. 29 CFR 780.105 - “Primary” and “secondary” agriculture under section 3(f).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false âPrimaryâ and âsecondaryâ agriculture under section 3(f... EXEMPTIONS APPLICABLE TO AGRICULTURE, PROCESSING OF AGRICULTURAL COMMODITIES, AND RELATED SUBJECTS UNDER THE FAIR LABOR STANDARDS ACT General Scope of Agriculture Introductory § 780.105 “Primary” and...

  5. Inhibition of LINE-1 and Alu retrotransposition by exosomes encapsidating APOBEC3G and APOBEC3F.

    PubMed

    Khatua, Atanu K; Taylor, Harry E; Hildreth, James E K; Popik, Waldemar

    2010-04-25

    Human cytidine deaminases, including APOBEC3G (A3G) and A3F, are part of a cellular defense system against retroviruses and retroelements including non-LTR retrotransposons LINE-1 (L1) and Alu. Expression of cellular A3 proteins is sufficient for inhibition of L1 and Alu retrotransposition, but the effect of A3 proteins transferred in exosomes on retroelement mobilization is unknown. Here, we demonstrate for the first time that exosomes secreted by CD4(+)H9 T cells and mature monocyte-derived dendritic cells encapsidate A3G and A3F and inhibit L1 and Alu retrotransposition. A3G is the major contributor to the inhibitory activity of exosomes, however, the contribution of A3F in H9 exosomes cannot be excluded. Additionally, we show that exosomes encapsidate mRNAs coding for A3 proteins. A3G mRNA, and less so A3F, was enriched in exosomes secreted by H9 cells. Exosomal A3G mRNA was functional in vitro. Whether exosomes inhibit retrotransposons in vivo requires further investigation.

  6. Immunotoxicological Profile of Chloroform in Female B6c3f1 Mice When Administered In Drinking Water

    EPA Science Inventory

    Chloroform can be formed as a disinfection by-product during water chlorination, one of the primary modalities for purifying municipal water supplies for human consumption. The goal of this study was to characterize the immunotoxic effects of chloroform in female B6C3F1 mice when...

  7. Search and Rescue Aircrewman/HH3F Avionics, 2-11. Military Curriculum Materials for Vocational and Technical Education.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This self-paced, individualized course, adapted from military curriculum materials for use in vocational and technical education, teaches students the skills needed to become a qualified avionics worker and aircrew rescuer on the HH-3F helicopter. The course materials consist of four pamphlets: two student workbooks and two student syllabuses. The…

  8. A POU3F4 Mutation Causes Nonsyndromic Hearing Loss in a Chinese X-linked Recessive Family

    PubMed Central

    Du, Wan; Han, Ming-Kun; Wang, Da-Yong; Han, Bing; Zong, Liang; Lan, Lan; Yang, Ju; Shen, Qi; Xie, Lin-Yi; Yu, Lan; Guan, Jing; Wang, Qiu-Ju

    2017-01-01

    Background: The molecular genetic research showed the association between X-linked hearing loss and mutations in POU3F4. This research aimed to identify a POU3F4 mutation in a nonsyndromic X-linked recessive hearing loss family. Methods: A series of clinical evaluations including medical history, otologic examinations, family history, audiologic testing, and a high-resolution computed tomography scan were performed for each patient. Bidirectional sequencing was carried out for all polymerase chain reaction products of the samples. Moreover, 834 controls with normal hearing were also tested. Results: The pedigree showed X-linkage recessive inheritance pattern, and pathogenic mutation (c.499C>T) was identified in the proband and his family member, which led to a premature termination prior to the entire POU domains. This mutation co-segregated with hearing loss in this family. No mutation of POU3F4 gene was found in 834 controls. Conclusions: A nonsense mutation is identified in a family displaying the pedigree consistent with X-linked recessive pattern in POU3F4 gene. In addition, we may provide molecular diagnosis and genetic counseling for this family. PMID:28051029

  9. Evaluation of Radial Flow Fluidized Filter (R3F) Followed by Microfiltration and Ultrafiltration Systems in Calimesa, California

    EPA Science Inventory

    U.S. EPA coordinated a field study with South Mesa Water Utility to look for treatment alternatives for California State Project Water in the small community of Calimesa, California. EPA evaluated the performance of a system comprised of Radial Flow Fluidized Filtration (R3f) fo...

  10. 29 CFR 780.158 - Examples of other practices within section 3(f) if requirements are met.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... a farm as an incident to or in conjunction with the farming operations conducted by such farmer or on such farm in addition to the practices listed in section 3(f). The selling (including selling at... agricultural commodities, dairy products, etc., is such a practice provided it does not amount to a...

  11. 29 CFR 780.158 - Examples of other practices within section 3(f) if requirements are met.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... a farm as an incident to or in conjunction with the farming operations conducted by such farmer or on such farm in addition to the practices listed in section 3(f). The selling (including selling at... agricultural commodities, dairy products, etc., is such a practice provided it does not amount to a...

  12. 29 CFR 780.158 - Examples of other practices within section 3(f) if requirements are met.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... a farm as an incident to or in conjunction with the farming operations conducted by such farmer or on such farm in addition to the practices listed in section 3(f). The selling (including selling at... agricultural commodities, dairy products, etc., is such a practice provided it does not amount to a...

  13. Mutagenicity of furan in female Big Blue B6C3F1 mice

    PubMed Central

    Terrell, Ashley N.; Huynh, Mailee; Grill, Alex E.; Kovi, Ramesh C.; O’Sullivan, M. Gerard; Guttenplan, Joseph B.; Ho, Yen-Yi; Peterson, Lisa A.

    2014-01-01

    Furan is an abundant food and environmental contaminant that is a potent liver carcinogen in rodent models. To determine if furan is genotoxic in vivo, female B6C3F1 Big Blue transgenic mice were treated with 15 mg/kg bw furan by gavage 5 days a week for 6 weeks, or once weekly for 3 weeks. Liver cII trans-gene mutation-frequency and mutation spectra were determined. Furan did not increase the mutation frequency under either treatment condition. In the 6-week treatment regimen, there was a change in the cII transgene mutation-spectrum, with the fraction of GC to AT transitions significantly reduced. The only other significant change was an increase in GC to CG transversions; these represented a minor contribution to the overall mutation spectrum. A much larger furan-dependent shift was observed in the 3-week study. There was a significant increase in transversion mutations, predominantly GC to TA transversions as well as smaller non-significant changes in GC to CG and AT to TA transversions. To determine if these mutations were caused by cis-2-butene-1,4-dial (BDA), a reactive metabolite of furan, the mutagenic activity and the mutation spectrum of BDA was determined in vitro, in Big Blue mouse embryonic fibroblasts. This compound did not increase the cII gene mutation-frequency but caused a substantial increase in AT to CG transversions. This increase, however, lost statistical significance when adjusted for multiple comparisons. Together, these findings suggest that BDA may not be directly responsible for the in-vivo effects of furan on mutational spectra. Histopathological analysis of livers from furan-treated mice revealed that furan induced multifocal, hepatocellular necrosis admixed with reactive leukocytes and pigment-laden Kupffer cells, enhanced oval-cell hyperplasia, and increased hepatocyte mitoses, some of which were atypical. An indirect mechanism of genotoxicity is proposed in which chronic toxicity followed by inflammation and secondary cell

  14. Mutagenicity of furan in female Big Blue B6C3F1 mice.

    PubMed

    Terrell, Ashley N; Huynh, Mailee; Grill, Alex E; Kovi, Ramesh C; O'Sullivan, M Gerard; Guttenplan, Joseph B; Ho, Yen-Yi; Peterson, Lisa A

    2014-08-01

    Furan is an abundant food and environmental contaminant that is a potent liver carcinogen in rodent models. To determine if furan is genotoxic in vivo, female B6C3F1 Big Blue transgenic mice were treated with 15 mg/kg bw furan by gavage 5 days a week for 6 weeks, or once weekly for 3 weeks. Liver cII transgene mutation-frequency and mutation spectra were determined. Furan did not increase the mutation frequency under either treatment condition. In the 6-week treatment regimen, there was a change in the cII transgene mutation-spectrum, with the fraction of GC to AT transitions significantly reduced. The only other significant change was an increase in GC to CG transversions; these represented a minor contribution to the overall mutation spectrum. A much larger furan-dependent shift was observed in the 3-week study. There was a significant increase in transversion mutations, predominantly GC to TA transversions as well as smaller non-significant changes in GC to CG and AT to TA transversions. To determine if these mutations were caused by cis-2-butene-1,4-dial (BDA), a reactive metabolite of furan, the mutagenic activity and the mutation spectrum of BDA was determined in vitro, in Big Blue mouse embryonic fibroblasts. This compound did not increase the cII gene mutation-frequency but caused a substantial increase in AT to CG transversions. This increase, however, lost statistical significance when adjusted for multiple comparisons. Together, these findings suggest that BDA may not be directly responsible for the in-vivo effects of furan on mutational spectra. Histopathological analysis of livers from furan-treated mice revealed that furan induced multifocal, hepatocellular necrosis admixed with reactive leukocytes and pigment-laden Kupffer cells, enhanced oval-cell hyperplasia, and increased hepatocyte mitoses, some of which were atypical. An indirect mechanism of genotoxicity is proposed in which chronic toxicity followed by inflammation and secondary cell

  15. Synthesis, structures and properties of the new lithium cobalt(II) phosphate Li{sub 4}Co(PO{sub 4}){sub 2}

    SciTech Connect

    Glaum, R.; Gerber, K.; Schulz-Dobrick, M.

    2012-04-15

    {alpha}-Li{sub 4}Co(PO{sub 4}){sub 2} has been synthesized and crystallized by solid-state reactions. The new phosphate crystallizes in the monoclinic system (P2{sub 1}/a, Z=4, a=8.117(3) Angstrom-Sign , b=10.303(8) Angstrom-Sign , c=8.118(8) Angstrom-Sign , {beta}=104.36(8) Angstrom-Sign ) and is isotypic to {alpha}-Li{sub 4}Zn(PO{sub 4}){sub 2}. The structure of {alpha}-Li{sub 4}Co(PO{sub 4}){sub 2} has been determined from single-crystal X-ray diffraction data {l_brace}R{sub 1}=0.040, wR{sub 2}=0.135, 2278 unique reflections with F{sub o}>4{sigma}(F{sub o}){r_brace}. The crystal structure, which might be regarded as a superstructure of the wurtzite structure type, is build of layers of regular CoO{sub 4}, PO{sub 4} and Li1O{sub 4} tetrahedra. Lithium atoms Li2, Li3 and Li4 are located between these layers. Thermal investigations by in-situ XRPD, DTA/TG and quenching experiments suggest decomposition followed by formation and phase transformation of Li{sub 4}Co(PO{sub 4}){sub 2}: {alpha}-Li{sub 4}Co(PO{sub 4}){sub 2} Long-Rightwards-Double-Arrow {sup 442 Degree-Sign C}{beta}-Li{sub 3}PO{sub 4}+LiCoPO{sub 4} Rightwards-Harpoon-Over-Leftwards-Harpoon {sup 773 Degree-Sign C}{beta}-Li{sub 4}Co(PO{sub 4}){sub 2} Long-Rightwards-Double-Arrow {sup quenchingto25 Degree-Sign C}{alpha}-Li{sub 4} Co(PO{sub 4}){sub 2} According to HT-XRPD at {theta}=850 Degree-Sign C{beta}-Li{sub 4}Co(PO{sub 4}){sub 2} (Pnma, Z=2, 10.3341(8) A, b=6.5829(5) A, c=5.0428(3) Angstrom-Sign ) is isostructural to {gamma}-Li{sub 3}PO{sub 4}. The powder reflectance spectrum of {alpha}-Li{sub 4}Co(PO{sub 4}){sub 2} shows the typical absorption bands for the tetrahedral chromophore [Co{sup II}O{sub 4}]. - Graphical abstract: The complex formation and decomposition behavior of Li{sub 4}Co(PO{sub 4}){sub 2} with temperature has been elucidated. The crystal structure of its {alpha}-phase was determined from single crystal data, HT-XRPD allowed derivation of a structure model for the {beta}-phase. Both

  16. High Resolution Infrared Spectroscopy of CH_3F-({ortho}-H_2){n} Cluster in Solid {para}-H_2

    NASA Astrophysics Data System (ADS)

    Kawasaki, Hiroyuki; Mizoguchi, Asao; Kanamori, Hideto

    2015-06-01

    The absorption spectrum of the ν3 (C-F stretching) mode of CH_3F in solid {para}-H_2 by FTIR showed a series of equal interval peaks. Their interpretation was that the {}-th peak of this series was due to CH_3F-({ortho}-H_2){n} clusters which were formed CH_3F and {n}'s {ortho}-H_2 in first nearest neighbor sites of the {para}-H_2 crystal with {hcp} structure. In order to understand this system in more detail, we have studied these peaks, especially {n} = 0 - 3 corresponding to 1037 - 1041 wn, by using high-resolution and high-sensitive infrared quantum cascade (QC) laser spectroscopy. Before now, we found many peaks around each {n}-th peak of the cluster, which we didn't know their origins. We observed photochromic phenomenon of these peaks by taking an advantage of the high brightness of the laser. In this study, we focus on satellite series consisting of six peaks which locate at the lower energy side of each main peak. All the peaks showed a common red shouldered line profile, which corresponds to partly resolved transitions of {ortho}- and {para}- CH_3F. The spectral pattern and time behavior of the peaks may suggest that these satellite series originate from a family of CH_3F clusters involving {ortho}-H_2 in second nearest neighbor sites. A model function assuming this idea is used to resolve the observed spectrum into each Lorentzian component, and then some common features of the satellite peaks are extracted and the physical meanings of them will be discussed. K. Yoshioka and D. T. Anderson, J. Chem. Phys. 119 (2003) 4731-4742 A. R. W. McKellar, A. Mizoguchi, and H. Kanamori, J. Chem. Phys. 135 (2011) 124511 A. R. W. McKellar, A. Mizoguchi, and H. Kanamori, Phys. Chem. Chem. Phys. 13 (2011) 11587-11589.

  17. Electron-impact total ionization cross sections of CF4, C2F6, and C3F8

    NASA Astrophysics Data System (ADS)

    Nishimura, H.; Huo, Winifred M.; Ali, M. A.; Kim, Yong-Ki

    1999-02-01

    Both theoretical and experimental electron-impact total ionization cross sections of CF4, C2F6, and C3F8 are presented. The experimental cross sections have been measured as a function of incident electron energy T from threshold to 3 keV. A parallel plate condenser type apparatus was used. The molecular polarizability for C3F8 was empirically estimated to be α=10.6 Å3±0.8 Å3. Theoretical cross sections calculated from the binary-encounter-Bethe (BEB) method, which combines a modified form of the Mott cross section and the Bethe cross section, are compared with the experimental cross sections. The BEB cross sections calculated from correlated molecular wave functions with theoretical estimates for multiple ionization are about 10% higher than the experimental data at the peak for CF4, while they are in excellent agreement with the experimental data for C2F6 and C3F8. Our analysis shows that the BEB theory implicitly includes part of neutral dissociation, such as CF4→CF3+F, and hence tends to be an upper limit to the total ionization cross section. We found that the difference between our best theory for CF4 and the present experimental cross section exhibits a remarkable similarity to the shape of the recently measured cross section for neutral dissociation, though there is no a priori reason for the similarity. Owing to the large number of bound electrons, the correlation included in our wave functions for C2F6 and C3F8 is more limited than for CF4. Hence, we believe that for these two molecules the calculated cross sections are lower than the true BEB values, in spite of the apparent excellent agreement between the theory and the experiment.

  18. The cooling capabilities of C2F6/C3F8 saturated fluorocarbon blends for the ATLAS silicon tracker

    NASA Astrophysics Data System (ADS)

    Bates, R.; Battistin, M.; Berry, S.; Bitadze, A.; Bonneau, P.; Bousson, N.; Boyd, G.; Botelho-Direito, J.; Crespo-Lopez, O.; DiGirolamo, B.; Doubek, M.; Giugni, D.; Hallewell, G.; Lombard, D.; Katunin, S.; McMahon, S.; Nagai, K.; Robinson, D.; Rossi, C.; Rozanov, A.; Vacek, V.; Zwalinski, L.

    2015-03-01

    We investigate and address the performance limitations of the ATLAS silicon tracker fluorocarbon evaporative cooling system operation in the cooling circuits of the barrel silicon microstrip (SCT) sub-detector. In these circuits the minimum achievable evaporation temperatures with C3F8 were higher than the original specification, and were thought to allow an insufficient safety margin against thermal runaway in detector modules subject to a radiation dose initially foreseen for 10 years operation at LHC. We have investigated the cooling capabilities of blends of C3F8 with molar admixtures of up to 25% C2F6, since the addition of the more volatile C2F6 component was expected to allow a lower evaporation temperature for the same evaporation pressure.A custom built recirculator allowed the in-situ preparation of C2F6/C3F8 blends. These were circulated through a representative mechanical and thermal setup reproducing an as-installed ATLAS SCT barrel tracker cooling circuit. Blend molar compositions were verified to a precision of 3.10-3 in a custom ultrasonic instrument.Thermal measurements in a range of C2F6/C3F8 blends were compared with measurements in pure C3F8. These indicated that a blend with 25% C2F6 would allow a reduction in evaporation temperature of around 9oC to below -15oC, even at the highest module power dissipations envisioned after 10 years operation at LHC. Such a reduction would allow more than a factor two in safety margin against temperature dependant leakage power induced thermal runaway.Furthermore, a blend containing up to 25% C2F6 could be circulated without changes to the on-detector elements of the existing ATLAS inner detector evaporative cooling system.

  19. Exchange bias effect in Au-Fe3O4sub> dumbbell nanoparticles induced by the charge transfer from gold

    SciTech Connect

    Feygenson, Mikhail; Bauer, John C; Gai, Zheng; Marques, Carlos; Aronson, Meigan C.; Teng, Xiaowei; Su, Dong; Stanic, Vesna; Urban, Volker S; Kevin, Beyer; Dai, Sheng

    2015-08-10

    We have studied the origin of the exchange bias effect in the Au-Fe3O4sub> dumbbell nanoparticles in two samples with different sizes of the Au seed nanoparticles (4.1 and 2.7 nm) and same size of Fe3O4sub> nanoparticles (9.8 nm). The magnetization, small-angle neutron scattering, synchrotron x-ray diffraction and scanning transmission electron microscope measurements determined the antiferromagnetic FeO wüstite phase within Fe3O4sub> nanoparticles, originating at the interface with the Au nanoparticles. The interface between antiferromagnetic FeO and ferrimagnetic Fe3O4sub> is giving rise to the exchange bias effect. The strength of the exchange bias fields depends on the interfacial area and lattice mismatch between both phases. We propose that the charge transfer from the Au nanoparticles is responsible for a partial reduction of the Fe3O4sub> into FeO phase at the interface with Au nanoparticles. The Au-O bonds are formed across the interface to accommodate an excess of oxygen released during the reduction of magnetite.

  20. The effect of Mo doping on the charge separation dynamics and photocurrent performance of BiVO 4sub> photoanodes

    SciTech Connect

    Pattengale, Brian; Huang, Jier

    2016-01-01

    Doping with electron-rich elements in BiVO4sub> photoanodes has been demonstrated as a desirable approach for improving their carrier mobility and charge separation efficiency. However, the effect of doping and dopant concentration on the carrier dynamics and photoelectrochemical performance remains unclear. In this work, we examined the effects of Mo doping on the charge separation dynamics and photocurrent performance in BiVO4sub> photoanodes. We show that the photocurrent of BiVO4sub> photoanodes increases with increasing concentration of the Mo dopant, which can be attributed to both the improved carrier mobility resulting from increased electron density and charge separation efficiency due to the diminishing of trap states upon Mo doping. The effect of doping on the electronic structure, carrier dynamics and photocurrent performance of BiVO4sub> photoanodes resulting from W and Mo dopants was also compared and discussed in this study. The knowledge gained from this work will provide important insights into the optimization of the carrier mobility and charge separation efficiency of BiVO4sub> photoanodes by controlling the dopants and their concentrations.

  1. Discovery of Fe–Ce Oxide/BiVO 4sub> Photoanodes through Combinatorial Exploration of Ni–Fe–Co–Ce Oxide Coatings

    SciTech Connect

    Shinde, Aniketa; Guevarra, Dan; Liu, Guiji; Sharp, Ian D.; Toma, Francesca M.; Gregoire, John M.; Haber, Joel A.

    2016-08-23

    An efficient photoanode is a prerequisite for a viable solar fuels technology. The challenges to realizing an efficient photoanode include the integration of a semiconductor light absorber and a metal oxide electrocatalyst to optimize corrosion protection, light trapping, hole transport, and photocarrier recombination sites. In order to efficiently explore metal oxide coatings, we employ a high throughput methodology wherein a uniform BiVO4sub> film is coated with 858 unique metal oxide coatings covering a range of metal oxide loadings and the full (Ni-Fe-Co-Ce)Ox pseudo-quaternary composition space. Photoelectrochemical characterization of the photoanodes reveals that specific combinations of metal oxide composition and loading provide up to a 13-fold increase in the maximum photoelectrochemical power generation for oxygen evolution in pH 13 electrolyte. Through mining of the high throughput data we identify composition regions that form improved interfaces with BiVO4sub>. Of particular note, integrated photoanodes with catalyst compositions in the range Fe(0.4-0.6)Ce(0.6-0.4)sub>Ox exhibit high interface quality and excellent photoelectrochemical power conversion. Furthermore, for scaled-up inkjet-printed electrodes and photoanodic electrodeposition of this composition on BiVO4sub> we can confirm the discovery and the synthesis-independent interface improvement of (Fe-Ce)Ox coatings on BiVO4sub>.

  2. CuCo2O4sub> ORR/OER Bi-functional catalyst: Influence of synthetic approach on performance

    SciTech Connect

    Serov, Alexey; Andersen, Nalin I.; Roy, Aaron J.; Matanovic, Ivana; Artyushkova, Kateryna; Atanassov, Plamen

    2015-02-07

    A series of CuCo2O4sub> catalysts were synthesized by pore forming, sol-gel, spray pyrolysis and sacrificial support methods. Catalysts were characterized by XRD, SEM, XPS and BET techniques. The electrochemical activity for the oxygen reduction and oxygen evolution reactions (ORR and OER) was evaluated in alkaline media by RRDE. Density Functional Theory was used to identify two different types of active sites responsible for ORR/OER activity of CuCo2O4sub> and it was found that CuCo2O4 sub>can activate the O-O bond by binding molecular oxygen in bridging positions between Co or Co and Cu atoms. It was found that the sacrificial support method (SSM) catalyst has the highest performance in both ORR and OER and has the highest content of phase-pure CuCo2O4sub>. It was shown that the presence of CuO significantly decreases the activity in oxygen reduction and oxygen evolution reactions. As a result, the half-wave potential (E1/2) of CuCo2O4sub>-SSM was found as 0.8 V, making this material a state-of-the-art, unsupported oxide catalyst.

  3. Accuracy in the isotope dilution mass spectrometry of uranium in rubidium uranium sulphate Rb[sub 2]U(SO[sub 4])[sub 3

    SciTech Connect

    Ramakumar, K.L.; Jeyakumar, S.; Raman, V.A.; Gnanayyan, L.; Rao, R.; Saxena, M.K.; Kavimandan, V.D.; Jain, H.C. )

    1993-05-01

    Problems encountered in the determination of uranium in rubidium uranium sulphate (Rb[sub 2]U(SO[sub 4])[sub 3]) employing isotope dilution thermal ionization mass spectrometry (ID-TIMS) are discussed. The positive bias of 0.2 to 0.3% in the determination of uranium in Rb[sub 2]U(SO[sub 4])[sub 3] by ID-TIMS with respect to the stoichiometric composition has been resolved by modifying the chemical exchange procedures. The concentration of uranium in Rb[sub 2]U(SO[sub 4])[sub 3] could be determined with an accuracy better than 0.1% employing the HClO[sub 4] treatment for proper isotopic exchange between the spike and sample isotopes. 12 refs., 1 fig., 5 tabs.

  4. Graphitic C3N4sub> as a new saturable absorber for the mid-infrared spectral range.

    PubMed

    Fan, Mingqi; Li, Tao; Li, Guiqiu; Ma, Houyi; Zhao, Shengzhi; Yang, Kejian; Kränkel, Christian

    2017-01-15

    The saturable absorption properties of few-layer graphitic carbon nitride (g-C3N4sub>) nanosheets near 3 μm were investigated. A stable Q-switched Er:Lu2O3 laser at 2.84 μm was realized by using a home-made g-C3N4sub> saturable absorber (SA), generating a pulse duration of 351 ns and an average output power of 1.09 W at a repetition rate of 99 kHz, corresponding to a pulse energy of 11.1 μJ. Our result indicates a great potential of g-C3N4sub> as a new SA in the 3 μm wavelength range.

  5. Femtosecond-laser-written Tm:KLu(WO4sub>)2 waveguide lasers.

    PubMed

    Kifle, Esrom; Mateos, Xavier; de Aldana, Javier Rodríguez Vázquez; Ródenas, Airan; Loiko, Pavel; Choi, Sun Yung; Rotermund, Fabian; Griebner, Uwe; Petrov, Valentin; Aguiló, Magdalena; Díaz, Francesc

    2017-03-15

    Depressed-index channel waveguides with a circular and photonic crystal cladding structures are prepared in a bulk monoclinic Tm:KLu(WO4sub>)2 crystal by 3D direct femtosecond laser writing. The channel waveguide structures are characterized and laser operation is achieved using external mirrors. In the continuous-wave mode, the maximum output power of 46 mW is achieved at 1912 nm corresponding to a slope efficiency of 15.2% and a laser threshold of only 21 mW. Passive Q-switching of a waveguide with a circular cladding is realized using single-walled carbon nanotubes. Stable 7 nJ/50 ns pulses are achieved at a repetition rate of 1.48 MHz. This first demonstration of ∼2  μm fs-laser-written waveguide lasers based on monoclinic double tungstates is promising for further lasers of this type doped with Tm3+ and Ho3+  ions.

  6. The structure of (CENP-A-H4)<sub>2 reveals physical features that mark centromeres

    SciTech Connect

    Sekulic, Nikolina; Bassett, Emily A; Rogers, Danielle J; Black, Ben E

    2010-09-20

    Centromeres are specified epigenetically, and the histone H3 variant CENP-A is assembled into the chromatin of all active centromeres. Divergence from H3 raises the possibility that CENP-A generates unique chromatin features to mark physically centromere location. Here we report the crystal structure of a subnucleosomal heterotetramer, human (CENP-A-H4)<sub>2, that reveals three distinguishing properties encoded by the residues that comprise the CENP-A targeting domain (CATD; ref. 2): (1) a CENP-A-CENP-A interface that is substantially rotated relative to the H3-H3 interface; (2) a protruding loop L1 of the opposite charge as that on H3; and (3) strong hydrophobic contacts that rigidify the CENP-A-H4 interface. Residues involved in the CENP-A-CENP-A rotation are required for efficient incorporation into centromeric chromatin, indicating specificity for an unconventional nucleosome shape. DNA topological analysis indicates that CENP-A-containing nucleosomes are octameric with conventional left-handed DNA wrapping, in contrast to other recent proposals. Our results indicate that CENP-A marks centromere location by restructuring the nucleosome from within its folded histone core.

  7. Compact KGd(WO4sub>)2 picosecond pulse-train synchronously pumped broadband Raman laser.

    PubMed

    Gao, Xiao Qiang; Long, Ming Liang; Meng, Chen

    2016-08-20

    We demonstrate an efficient approach to realizing an extra-cavity, synchronously pumped, stimulated Raman cascaded process under low repetition frequency (1 kHz) pump conditions. We also construct a compact KGd(WO4sub>)2 (KGW) crystal picosecond Raman laser that has been configured as the developed method. A pulse-train green laser pumped the corresponding 70 mm long KGW crystal Raman cavity. The pulse train contains six pulses, about 800 ps separated, for every millisecond; thus, it can realize synchronous pumping between pump pulse and the pumped Raman cavity. The investigated system produced a collinear Raman laser output that includes six laser lines covering the 532 to 800 nm spectra. This is the first report on an all-solid-state, high-average-power picosecond collinear multi-wavelength (more than three laser components) laser to our knowledge. This method has never been reported on before in the synchronously pumped stimulated Raman scattering (SRS) realm.

  8. Nonperturbative tests for asymptotic freedom in the PT-symmetric (-{phi}{sup 4}){sub 3+1} theory

    SciTech Connect

    Shalaby, Abouzeid; Al-Thoyaib, Suleiman S.

    2010-10-15

    In the literature, the asymptotic freedom property of the (-{phi}{sup 4}) theory is always concluded from real-line calculations while the theory is known to be a non-real-line one. In this article, we test the existence of the asymptotic freedom in the (-{phi}{sup 4}){sub 3+1} theory using the mean field approach. In this approach and contrary to the original Hamiltonian, the obtained effective Hamiltonian is rather a real-line one. Accordingly, this work resembles the first reasonable analysis for the existence of the asymptotic freedom property in the PT-symmetric (-{phi}{sup 4}) theory. In this respect, we calculated three different amplitudes of different positive dimensions (in mass units) and find that all of them go to very small values at high energy scales (small coupling) in agreement with the spirit of the asymptotic freedom property of the theory. To test the validity of our calculations, we obtained the asymptotic behavior of the vacuum condensate in terms of the coupling, analytically, and found that the controlling factor {Lambda} has the value ((4{pi}){sup 2}/6)=26.319 compared to the result {Lambda}=26.3209 from the literature, which was obtained via numerical predictions. We assert that the nonblowup of the massive quantities at high energy scales predicted in this work strongly suggests the possibility of the solution of the famous hierarchy puzzle in a standard model with the PT-symmetric Higgs mechanism.

  9. Magnetic susceptibility, specific heat and magnetic structure of CuNi{sub 2}(PO{sub 4}){sub 2}

    SciTech Connect

    Escobal, Jaione; Pizarro, Jose L.; Mesa, Jose L. . E-mail: joseluis.mesa@ehu.es; Larranaga, Aitor; Fernandez, Jesus Rodriguez; Arriortua, Maria I.; Rojo, Teofilo

    2006-10-15

    CuNi{sub 2}(PO{sub 4}){sub 2} phosphate has been synthesized by the ceramic method at 800 deg. C in air. The crystal structure consists of a three-dimensional skeleton constructed from MO{sub 4} (M{sup II} =Cu and Ni) planar squares and M{sub 2}O{sub 8} dimers with square pyramidal geometry, which are interconnected by (PO{sub 4}){sup 3-} oxoanions with tetrahedral geometry. The magnetic behavior has been studied on powdered sample by using susceptibility, specific heat and neutron diffraction data. The bimetallic copper(II)-nickel(II) orthophosphate exhibits a three-dimensional magnetic ordering at, approximately, 29.8 K. However, its complex crystal structure hampers any parametrization of the J-exchange parameter. The specific heat measurements exhibit a three-dimensional magnetic ordering ({lambda}-type) peak at 29.5 K. The magnetic structure of this phosphate shows ferromagnetic interactions inside the Ni{sub 2}O{sub 8} dimers, whereas the sublattice of Cu(II) ions presents antiferromagnetic couplings along the y-axis. The change of the sign in the magnetic unit-cell, due to the [1/2, 0, 1/2] propagation vector determines a purely antiferromagnetic structure. - Graphical abstract: Magnetic structure of CuNi2(PO4)2.

  10. SU(4){sub L} x U(1){sub X} three-family model for the electroweak interaction

    SciTech Connect

    Sanchez, Luis A.; Wills-Toro, Luis A.; Zuluaga, Jorge I.

    2008-02-01

    An extension of the gauge group SU(2){sub L} x U(1){sub Y} of the standard model to the symmetry group SU(4){sub L} x U(1){sub X} (3-4-1 for short) is presented. The model does not contain exotic electric charges and anomaly cancellation is achieved with a family of quarks transforming differently from the other two, thus leading to FCNC. By introducing a discrete Z{sub 2} symmetry we obtain a consistent fermion mass spectrum, and avoid unitarity violation of the Cabibbo-Kobayashi-Maskawa mixing matrix arising from the mixing of ordinary and exotic quarks. The neutral currents coupled to all neutral vector bosons are studied, and by using CERN LEP and SLAC Linear Collider data at Z-pole and atomic parity violation data, we bound parameters of the model related to tree-level Z-Z{sup '} mixing. These parameters are further constrained by using experimental input from neutral meson mixing in the analysis of sources of FCNC present in the model. Constraints coming from the contribution of exotic particles to the one-loop oblique electroweak parameters S, T and U are also briefly discussed. Finally, a comparison is done of the predictions of different classes of 3-4-1 models without exotic electric charges.

  11. (H3O)2NaAl3F12, isostructural with A2NaAl3F12 (A = K(+), Rb(+), Cs(+)) fluorides having HTB-type sheets.

    PubMed

    Jouffret, Laurent; Lhoste, Jerome; Hemon-Ribaud, Annie; Leblanc, Marc; Maisonneuve, Vincent

    2014-05-01

    The title compound, (H3O)2NaAl3F12 [dihydronium sodium trialuminum(III) dodecafluoride], was obtained by solvothermal synthesis from the reaction of aluminium hydroxide, sodium hydroxide, 1,2,4-triazole and aqueous HF in ethanol at 463 K for 48 h. The structure consists of AlF6 octahedra organized in [AlF4(-)]n HTB-type sheets (HTB is hexagonal tungsten bronze) separated by H3O(+) and Na(+) cations.

  12. Oxygen trapped by rare earth tetrahedral clusters in Nd4sub>FeOS6: Crystal structure, electronic structure, and magnetic properties

    SciTech Connect

    Lin, Qisheng; Taufour, Valentin; Zhang, Yuemei; Wood, Max; Drtina, Thomas; Bud’ko, Sergey L.; Canfield, Paul C.; Miller, Gordon J.

    2015-05-22

    Single crystals of Nd4sub>FeOS6 were grown from an Fe-S eutectic solution. Single crystal X-ray diffraction analysis revealed a Nd4sub>MnOSe6-type structure (P63mc, a = 9.2693(1) Å, c = 6.6650(1) Å, V = 495.94(1) Å3, Z = 2), featuring parallel chains of face-sharing [FeS6x1/2]4- trigonal antiprisms and interlinked [Nd4sub>OS3]4+ cubane-like clusters. Oxygen atoms were found to be trapped by Nd4 clusters in the [Nd4OS3]4+ chains. Structural differences among Nd4sub>MnOSe6-type Nd4sub>FeOS6 and the related La3CuSiS7- and Pr8CoGa3-type structures have been described. Magnetic susceptibility measurements on Nd4sub>FeOS6 suggested the dominance of antiferromagnetic interactions at low temperature, but no magnetic ordering down to 2 K was observed. Spin-polarized electronic structure calculations revealed magnetic frustration with dominant antiferromagnetic interactions.

  13. New structure of high-pressure body-centered orthorhombic Fe2SiO4sub>

    SciTech Connect

    Yamanaka, Takamitsu; Kyono, Atsushi; Nakamoto, Yuki; Kharlamova, Svetlana; Struzhkin, Viktor V.; Gramsch, Stephen A.; Mao, Ho-kwang; Hemley, Russell J.

    2015-08-01

    Here, a structural change in Fe2SiO4sub> spinel and the structure of a new high pressure phase are determined by Rietveld 26 profile fitting of x-ray diffraction data up to 64 GPa at ambient temperature. The compression curve of the spinel is discontinuous at approximately 20 GPa. Fe Kβ x-ray emission measurements at high pressure show that the transition from a high spin (HS) to an intermediate spin (IS) state begins at 17 GPa in the spinel phase. The IS electronic state is gradually enhanced with pressure, which results in an isostructural phase transition. A transition from the cubic spinel structure to a body centered orthorhombic phase (I-Fe2SiO4sub>) with space group Imma and Z=4 was observed at approximately 34 GPa. The structure of I-Fe2SiO4sub> has two crystallographically distinct FeO6 octahedra, which are arranged in layers parallel to (101) and (011) and are very similar to the layers of FeO6 octahedra that constitute the spinel structure. Silicon also exists in six-fold coordination in I-Fe2SiO4sub>. The transformation to the new high-pressure phase is reversible under decompression at ambient temperature. A Martensitic transformation of each slab of the spinel structure with translation vector [$\\vec{1/8}$ $\\vec{1/8}$ $\\vec{1/8}$] generates the I-Fe2SiO4sub> structure. Laser heating of I-Fe2SiO4sub> at 1500 K results in a decomposition of the material to rhombohedral FeO and SiO2 stishovite.

  14. Relative quantum yield of I-asterisk(2P1/2) in the tunable laser UV photodissociation of i-C3F7I and n-C3F7I - Effect of temperature and exciplex emission

    NASA Technical Reports Server (NTRS)

    Smedley, J. E.; Leone, S. R.

    1983-01-01

    Wavelength-specific relative quantum yields of metastable I from pulsed laser photodissociation of i-C3F7I and n-C3F7I in the range 265-336 nm are determined by measuring the time-resolved infrared emission from the atomic I(P-2(1/2) P-2(3/2) transition. It is shown that although this yield appears to be unity from 265 to 298 nm, it decreases dramatically at longer wavelengths. Values are also reported for the enhancement of emission from metastable I due to exciplex formation at several temperatures. The exciplex formation emission increases linearly with parent gas pressure, but decreases with increasing temperature. Absorption spectra of i- and n-C3F7I between 303 and 497 K are presented, and the effect of temperature on the quantum yields at selected wavelengths greater than 300 nm, where increasing the temperature enhances the absorption considerably, are given. The results are discussed in regard to the development of solar-pumped iodine lasers.

  15. Photoluminescence and thermoluminescence properties of Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor

    SciTech Connect

    Gupta, Palvi; Bedyal, A.K.; Kumar, Vinay; Khajuria, Y.; Lochab, S.P.; Pitale, S.S.; Ntwaeaborwa, O.M.; Swart, H.C.

    2014-12-15

    Energy level diagram of Tb{sup 3+} ion in the K{sub 3}Gd(PO{sub 4}){sub 2} host lattice. - Highlights: • First time, a detailed TL and PL study on undoped and Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor. • Combustion method was employed to synthesize the Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor. • Mechanism of excitation and emission in undoped and Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor was given. - Abstract: Tb{sup 3+} doped nanoparticulate K{sub 3}Gd(PO{sub 4}){sub 2} phosphor was prepared by combustion method using urea as a fuel. The structure, optical and luminescent properties of the phosphor were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and thermoluminescence (TL) spectroscopy. In undoped K{sub 3}Gd(PO{sub 4}){sub 2}, the excitation and emission peaks at 273 nm and 323 nm belongs to the {sup 8}S{sub 7/2} → {sup 6}I{sub J(J=7/2)} and {sup 6}P{sub J(J=7/2)} → {sup 8} S{sub 7/2} transitions of Gd{sup 3+} while green emission was observed in the Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2}. TL study was carried out after exposing the samples to γ-radiations (0.1–5 kGy) in the K{sub 3}Gd(PO{sub 4}){sub 2}:Tb{sup 3+} (1.5 mol%). The calculated kinetic parameters were compared with different methods. The band gap of the phosphor was estimated as 5.80 eV. The green shade of the Tb{sup 3+} ion with the CIE coordinates (x, y) as (0.29, 0.54) was in good agreement with the well known green phosphors.

  16. Magnetic, Caloric and Crystallographic Properties of Dy5(SixGe1-x)4sub> Alloys

    SciTech Connect

    Ivchenko, Vitaliy Vladislavovich

    2002-01-01

    A study of a series of Dy5(SixGe1-x)4sub> alloys using dc and ac magnetic susceptibility, magnetization, heat capacity, and x-ray powder diffraction techniques revealed that the variation of the magnetic properties and crystal structures with composition is similar to that observed in the Gd5(SixGe1-x)4sub> system, except that the magnetic ordering temperatures are lower. The magnetic phase transition temperatures vary from ~ 46K (Dy5Ge4sub>) to ~ 137K (Dy5Si4sub>). The intermediate ternary phase Dy5Si3Ge undergoes a first order magnetic phase transition at ~ 65K. The value of magnetic entropy change for this composition is quite large (-34J/kgK for magnetic field change from 0 to 50kOe), compared to the values for the two end members (-7 J/kgK for Dy5Ge4sub> and -12.5J/kgK for Dy5Si4sub>). The magnetization and ac susceptibility measurements showed that alloys with monoclinic crystal structure have a non-collinear ordering of the magnetic moments at low temperatures. The alloy Dy5Si3Ge appears to exhibit a FM phase transition below the Curie temperature at 65K. Also a series of critical fields are observed at low temperature during magnetization vs magnetic field measurements in all of the Dy5(SixGe1-x)4sub> alloys regardless type of crystal structure. The Dy5(SixGe1-x)4sub> alloys, where 0.67≤x≤1, may be useful magnetic refrigerant materials in the ~50 to ~160K temperature range.

  17. Magnetic structures of R5Ni2In4sub> and R11Ni4sub>In9 ( R = Tb and Ho): Strong hierarchy in the temperature dependence of the magnetic ordering in the multiple rare-earth sublattices

    SciTech Connect

    Ritter, C.; Provino, A.; Manfrinetti, P.; Pecharsky, V. K.; Gschneidner, Jr., K. A.; Dhar, S. K.

    2015-11-09

    In this study, the magnetic properties and magnetic structures of the R5Ni2In4sub> and the microfibrous R 11Ni4sub>In9 compounds with R = Tb and Ho have been examined using magnetization, heat capacity, and neutron diffraction data. Rare earth atoms occupy three and five symmetrically inequivalent rare earth sites in R5Ni2In4sub> and R 11Ni4sub>In9 compounds, respectively. As a result of the intra- and inter-magnetic sublattice interactions, the magnetic exchange interactions are different for various rare earth sites; this leads to a cascade of magnetic transitions with a strong hierarchy in the temperature dependence of the magnetic orderings.

  18. Synthesis, crystal structure and spectroscopy properties of Na{sub 3} AZr(PO{sub 4}){sub 3} (A=Mg, Ni) and Li{sub 2.6}Na{sub 0.4}NiZr(PO{sub 4}){sub 3} phosphates

    SciTech Connect

    Chakir, M. . E-mail: fachakir@yahoo.fr; El Jazouli, A.; Waal, D. de

    2006-06-15

    Na{sub 3} AZr(PO{sub 4}){sub 3} (A=Mg, Ni) phosphates were prepared at 750 deg. C by coprecipitation route. Their crystal structures have been refined at room temperature from X-ray powder diffraction data using Rietveld method. Li{sub 2.6}Na{sub 0.4}NiZr(PO{sub 4}){sub 3} was synthesized through ion exchange from the sodium analog. These materials belong to the Nasicon-type structure. Raman spectra of Na{sub 3} AZr(PO{sub 4}){sub 3} (A=Mg, Ni) phosphates present broad peaks in favor of the statistical distribution in the sites around PO{sub 4} tetrahedra. Diffuse reflectance spectra indicate the presence of octahedrally coordinated Ni{sup 2+} ions. - Graphical abstract: Structure of Na{sub 3} AZr(PO{sub 4}){sub 3} (A=Mg, Ni) phosphates. Display Omitted.

  19. Optical properties of UV-induced color centers in a KY3F10:Ce3+ crystal

    NASA Astrophysics Data System (ADS)

    Tselishcheva, E. Yu.; Naumov, A. K.; Tselishchev, D. I.; Morozov, O. A.; Korableva, S. L.

    2013-06-01

    The evolution of color centers induced in a KY3F10:Ce3+ crystal by UV radiation has been observed and interpreted. It has been revealed that, initially, the UV irradiation of the KY3F10:Ce3+ crystal induces the formation of color centers predominantly of the F-type, which, in a short time period of about ten minutes, are transformed into complex color centers of the F 2-type, as well as into impurity color centers. Based on the data obtained, a diagram of energy states of the crystal, dopant, and color centers has been constructed, on which most probable processes that are caused by electronic transitions occurring in the KYF:Ce3+ crystal after its UV irradiation have been indicated.

  20. Intrinsic quantum anomalous Hall effect in the kagome lattice Cs2LiMn3F12

    DOE PAGES

    Xu, Gang; Lian, Biao; Zhang, Shou -Cheng

    2015-10-27

    In a kagome lattice, the time reversal symmetry can be broken by a staggered magnetic flux emerging from ferromagnetic ordering and intrinsic spin-orbit coupling, leading to several well-separated nontrivial Chern bands and intrinsic quantum anomalous Hall effect. Based on this idea and ab initio calculations, we propose the realization of the intrinsic quantum anomalous Hall effect in the single layer Cs2Mn3F12 kagome lattice and on the (001) surface of a Cs2LiMn3F12 single crystal by modifying the carrier coverage on it, where the band gap is around 20 meV. Furthermore, a simplified tight binding model based on the in-plane ddσ antibondingmore » states is constructed to understand the topological band structures of the system.« less

  1. Intrinsic Quantum Anomalous Hall Effect in the Kagome Lattice Cs_{2}LiMn_{3}F_{12}.

    PubMed

    Xu, Gang; Lian, Biao; Zhang, Shou-Cheng

    2015-10-30

    In a kagome lattice, the time reversal symmetry can be broken by a staggered magnetic flux emerging from ferromagnetic ordering and intrinsic spin-orbit coupling, leading to several well-separated nontrivial Chern bands and intrinsic quantum anomalous Hall effect. Based on this idea and ab initio calculations, we propose the realization of the intrinsic quantum anomalous Hall effect in the single layer Cs_{2}Mn_{3}F_{12} kagome lattice and on the (001) surface of a Cs_{2}LiMn_{3}F_{12} single crystal by modifying the carrier coverage on it, where the band gap is around 20 meV. Moreover, a simplified tight binding model based on the in-plane ddσ antibonding states is constructed to understand the topological band structures of the system.

  2. Phase transition and multicolor luminescence of Eu{sup 2+}/Mn{sup 2+}-activated Ca{sub 3}(PO{sub 4}){sub 2} phosphors

    SciTech Connect

    Li, Kai; Chen, Daqin; Xu, Ju; Zhang, Rui; Yu, Yunlong; Wang, Yuansheng

    2014-01-01

    Graphical abstract: We have synthesized Eu{sup 2+} doped and Eu{sup 2+}/Mn{sup 2+} co-doped Ca{sub 3}(PO{sub 4}){sub 2} phosphors. The emitting color varies from blue to green with increasing of Eu{sup 2+} content for the Eu{sup 2+}-doped phosphor, and the quantum yield of the 0.05Eu{sup 2+}: Ca{sub 2.95}(PO{sub 4}){sub 2} sample reaches 56.7%. Interestingly, Mn{sup 2+} co-doping into Eu{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} leads to its phase transition from orthorhombic to rhombohedral, and subsequently generates tunable multi-color luminescence from green to red via Eu{sup 2+} → Mn{sup 2+} energy transfer. - Highlights: • A series of novel Eu{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} phosphors were successfully synthesized. • Phase transition of Ca{sub 3}(PO{sub 4}){sub 2} from orthorhombic to rhombohedral occurred when Mn{sup 2+} ions were doped. • The phosphors exhibited tunable multi-color luminescence. • The quantum yield of 0.05Eu{sup 2+}: Ca{sub 2.95}(PO{sub 4}){sub 2} phosphor can reach 56.7%. • The analyses of phosphors were carried out by many measurements. - Abstract: Intense blue-green-emitting Eu{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} and tunable multicolor-emitting Eu{sup 2+}/Mn{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} phosphors are prepared via a solid-state reaction route. Eu{sup 2+}-doped orthorhombic Ca{sub 3}(PO{sub 4}){sub 2} phosphor exhibits a broad emission band in the wavelength range of 400–700 nm with a maximum quantum yield of 56.7%, and the emission peak red-shifts gradually from 479 to 520 nm with increase of Eu{sup 2+} doping content. Broad excitation spectrum (250–420 nm) of Eu{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} matches well with the near-ultraviolet LED chip, indicating its potential applications as tri-color phosphors in white LEDs. Interestingly, Mn{sup 2+} co-doping into Eu{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} leads to its phase transition from orthorhombic to rhombohedral, and subsequently generates tunable multi

  3. Efficiency of PBN to Trap 3-CAR in B6C3F1 Mouse Liver Slices: An EPR Study.

    DTIC Science & Technology

    1995-09-01

    AL/OE-TR-1995-0139 UNITED STATES AIR FORCE ARMSTRONG LABORATORY EFFICIENCY OF PBN TO TRAP 3-CAR IN B6C3F1 MOUSE LIVER SLICES: AN EPR STUDY...and Eckstein, JM. 1993 Comparative intestinal and testes toxicity of 4 aminothiols in irradiated and non-irradiated mice . Ann Clin and Lab Sei 23 (6...Air Force Armstrong Laboratory. Additional copies may be purchased from: National Technical Information Service 5285 Port Royal Road Springfield

  4. On the Jahn-Teller effect in the X∼2E electronic ground state of CH3F+

    NASA Astrophysics Data System (ADS)

    Sarkar, Rudraditya; Rajagopala Reddy, S.; Mahapatra, S.; Köppel, H.

    2017-01-01

    In view of recent experimental and theoretical developments, we revisit our earlier theoretical studies (Mahapatra et al., 2004, 2005) on the Jahn-Teller effect in the degenerate X∼2E electronic ground state of CH3F+. The electronic potential energy surfaces and the coupling surfaces are re-calculated employing state-of-the-art ab initio quantum chemistry methods. The vibronic Hamiltonian, constructed with the aid of multimode vibronic coupling theory and symmetry selection rules, is systematically extended to higher order in the Taylor series expansion and the parameters are carefully revised in the present study. First principles quantum dynamics study is carried out to calculate the vibronic eigenvalue spectrum of this degenerate electronic state of CH3F+. The vibronic energy levels are assigned and compared with the experimental pulsed-field-ionization zero-electron-kinetic energy (PFI-ZEKE) and one photon ZEKE spectra of CH3F+ and also with the earlier theoretical results reported in the literature.

  5. Measurement of absolute CO number densities in CH3F/O2 plasmas by optical emission self-actinometry

    NASA Astrophysics Data System (ADS)

    Karakas, Erdinc; Kaler, Sanbir; Lou, Qiaowei; Donnelly, Vincent M.; Economou, Demetre J.

    2014-02-01

    CH3F/O2 inductively coupled plasmas at 10 mTorr were investigated using optical emission spectroscopy. A ‘self-actinometry’ method was developed to measure the absolute number density of CO that formed in reactions following dissociation of CH3F and O2 in the plasma. In this method, small amounts of CO were added to the plasma, leading to small increases in the CO emission intensity. By carefully accounting for small perturbations to the plasma electron density and/or electron energy distribution, and by showing that very little of the CO added to the plasma was decomposed by electron impact or other reactions, it was possible to derive absolute number densities for the CO content of the plasma. With equal fractions (0.50) of CH3F and O2 in the feed gas, the CO mole fraction as a function of plasma power saturated at a value of 0.20-0.25. As O2 in the feed gas was varied at a constant power of 100 W, the CO mole fraction went through a maximum of about 0.25 near an O2 feed gas fraction of 0.5. The relative CO number densities determined by ‘standard’ actinometry followed the same functional dependence as the absolute mole fractions determined by self-actinometry, aided by the fact that electron temperature did not change appreciably with power or feed gas composition.

  6. Treatment of acute corneal hydrops with intracameral C3F8 in a patient of pellucid marginal degeneration with keratoglobus.

    PubMed

    Kaushal, Sameer; Sharma, Namrata; Vajpayee, Rasik B

    2007-11-01

    We report the use of perfluoropropane (C(3)F(8)) gas for the treatment of acute hydrops with intrastromal cleft in a case of pellucid marginal degeneration with keratoglobus. Acute hydrops in a 36-year-old man with pellucid marginal degeneration with keratoglobus was treated with intracameral injection of 0.3 mL isoexpansile C(3)F(8) (14%). Reduction in corneal haze was seen beginning from the third postoperative day. Significant clearing had taken place by the end of the second week with the closure of intrastromal cleft. Best corrected visual acuity improved from finger counting at 1 foot preoperatively to 6/18 after 2 weeks. There was no postoperative rise in intraocular pressure or cataract formation. Intracameral injection of C(3)F(8) may possibly be a viable treatment option for acute hydrops in a case of corneal ectasia. Larger studies are required to clarify the role of intracameral gas injection in the treatment of acute hydrops in corneal ectasia.

  7. Stabilization of MgAl2O4sub> spinel surfaces via doping

    SciTech Connect

    Hasan, Md. M.; Dholabhai, Pratik P.; Castro, Ricardo H. R.; Uberuaga, Blas P.

    2016-02-06

    Here, the surface structure of complex oxides plays a vital role in processes such as sintering, thin film growth, and catalysis, as well as being a critical factor determining the stability of nanoparticles. We report atomistic calculations of the low-index stoichiometric magnesium aluminate spinel (MgAl2O4sub>) surfaces, each with two different chemical terminations. High temperature annealing was used to explore the potential energy landscape and provide more stable surface structures. We find that the lowest energy surface is {100} while the highest energy surface is {111}. The surfaces were subsequently doped with three trivalent dopants (Y3+, Gd3+, La3+) and one tetravalent dopant (Zr4+) and both the surface segregation energies of the dopants and surface energies of the doped surface were determined. All of the dopants reduce the surface energy of spinel, though this reduction in energy depends on both the size and valence of the dopant. Dopants with larger ionic radius tend to segregate to the surface more strongly and reduce the surface energy to a greater extent. Furthermore, the ionic valence of the dopants seems to have a stronger influence on the segregation than does ionic size. For both undoped and doped spinel, the predicted crystal shape is dominated by {100} surfaces, but the relative fraction of the various surfaces changes with doping due to the unequal changes in energy, which has implications on equilibrium nanoparticle shapes and therefore on applications sensitive to surface properties.

  8. Single crystal synthesis and magnetism of the BaLn2O4sub> family (Ln = lanthanide)

    SciTech Connect

    Besara, Tiglet; Lundberg, Matthew S.; Sun, Jifeng; Ramirez, Daniel; Dong, Lianyang; Whalen, Jeffrey B.; Vasquez, Rafael; Herrera, Felix; Allen, John R.; Davidson, Michael W.; Siegrist, Theo

    2014-05-27

    The series of compounds in the BaLn2O4sub> family (Ln = La–Lu, Y) has been synthesized for the first time in single crystalline form, using a molten metal flux. The series crystallizes in the CaV2O4sub> structure type with primitive orthorhombic symmetry (space group Pnma, #62), and a complete structural study of atomic positions, bonds, angles, and distortions across the lanthanide series is presented. With the exception of the Y, La, Eu, and Lu members, magnetic susceptibility measurements were performed between 2 K and 300 K. BaCe2O4sub> and BaYb2O4sub> display large crystal fields effects and suppression of magnetic ordering. As a result, all compounds show signs of magnetic frustration due to the trigonal arrangements of the trivalent lanthanide cations in the structure.

  9. Kondo lattice and antiferromagnetic behavior in quaternary CeTAl4sub>Si2 (T = Rh, Ir) single crystals

    SciTech Connect

    Maurya, Arvind; Kulkarni, Ruta; Thamizhavel, Arumugam; Paudyal, Durga; Dhar, Sudesh Kumar

    2016-02-26

    Here, we have explored in detail the anisotropic magnetic properties of CeRhAl4sub>Si2 and CeIrAl4sub>Si2, which undergo two antiferromagnetic transitions, at TN1 = 12.6 and 15.5 K, followed by a second transition at TN2 = 9.4 and 13.8 K, respectively, with the [001]-axis as the relatively easy axis of magnetization. The electrical resistivity at ambient and applied pressure provides evidence of Kondo interaction in both compounds, further supported by a reduced value of the entropy associated with the magnetic ordering. The Sommerfeld coefficient γ is inferred to be 195.6 and 49.4 mJ/(mol K2) for CeRhAl4sub>Si2 and CeIrAl4sub>Si2, respectively, classifying these materials as moderate heavy-fermion compounds. The crystal electric field energy levels are derived from the peak seen in the Schottky heat capacity. Furthermore, we have also performed electronic structure calculations by using the local spin density approximation + U [LSDA+U] approach, which provide physical insights on the observed magnetic behavior of these two compounds.

  10. Low Temperature Propane Oxidation over Co3O4sub> based Nano-array Catalysts. Ni Dopant Effect, Reaction Mechanism and Structural Stability

    SciTech Connect

    Ren, Zheng; Wu, Zili; Gao, Puxian; Song, Wenqiao; Xiao, Wen; Guo, Yanbing; Ding, Jun; Suib, Steven L.; Gao, Pu-Xian

    2015-06-09

    Low temperature propane oxidation has been achieved by Co3O4sub>-based nano-array catalysts featuring low catalytic materials loading. The Ni doping into the Co3O4sub> lattice has led to enhanced reaction kinetics at low temperature by promoting the surface lattice oxygen activity. In situ DRIFTS investigation in tandem with isotopic oxygen exchange reveals that the propane oxidation proceeds via Mars-van Krevelen mechanism where surface lattice oxygen acts as the active site whereas O2 in the reaction feed does not directly participate in CO2 formation. The Ni doping promotes the formation of less stable carbonates on the surface to facilitate the CO2 desorption. The thermal stability of Ni doped Co3O4sub> decreases with increased Ni concentration while catalytic activity increases. A balance between enhanced activity and compromised thermal stability shall be considered in the Ni doped Co3O4sub> nano-array catalysts for low temperature hydrocarbon oxidation. This study provides useful and timely guidance for rational catalyst design toward low temperature catalytic oxidation.

  11. Solvothermal synthesis of monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} microspheres and their application as microwave absorber

    SciTech Connect

    Chen, Tingting; Sun, Genban; Ma, Shulan; Yang, Xiaojing; Hu, Changwen

    2012-03-15

    Graphical abstract: Monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} porous microspheres with shell structure were synthesized via a combined solvothermal method and calcination route. The radar-wave absorbability of the purple sample calcined at 900 Degree-Sign C was strongest at the frequency of about 8.5 GHz. Highlights: Black-Right-Pointing-Pointer In this study we synthesized monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} porous microspheres as microwave absorber. Black-Right-Pointing-Pointer The relationship between microstructures and the electromagnetic properties was indicated. Black-Right-Pointing-Pointer The radar-wave absorbability of the sample was included. -- Abstract: Monodispersed CoZr{sub 4}(PO{sub 4}){sub 6} microspheres with a diameter of 40 {mu}m were achieved via a combining solvothermal and calcination route. The crystallinity of the calcined microspheres with shell structure was improved, while the monodisperse property and morphologies remained. The possible formation mechanism of the porous CoZr{sub 4}(PO{sub 4}){sub 6} microspheres with nanoshell was proposed. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR) technologies, thermal analysis (TG and DSC), nitrogen adsorption-desorption isotherms and network analyzer. The sample calcined at 900 Degree-Sign C shows a strongest absorbability in the radar-wave absorbability test.

  12. Highly Selective Colorimetric and Luminescence Response of a Square-Planar Platinum(II) Terpyridyl Complex to Aqueous TcO4sub>-

    SciTech Connect

    Chatterjee, Sayandev; Norton, Amie E.; Edwards, Matthew K.; Peterson, James M.; Taylor, Stephen D.; Bryan, Samuel A.; Andersen, Amity; Govind, Niranjan; Albrecht-Schmitt, Thomas E.; Connick, William; Levitskaia, Tatiana G.

    2015-10-08

    In an effort to address the need for a rapid, selective and economical detection technique for aqueous pertechnetate (TcO4sub>-) anion based on recognition at the molecular level, simple salts of transition metal complexes that undergo a distinct spectroscopic change upon exposure to aqueous anions were explored. The Pt(II) complex [Pt(tpy)Br]SbF6 (tpy=2,2';6',2"-terpyridine) undergoes a dramatic color change and intense luminescence response upon TcO4sub>- uptake due to concomitant enhancement of Pt•••Pt interactions. The spectroscopic response was highly selective and quantitative for aqueous TcO4sub>- among other competing anions. Complimentary Raman spectroscopy and microscopy techniques, structural determination and theoretical methods were employed to achieve molecular-level understanding of the mechanism of the response to aqueous TcO4sub>-.

  13. Li/Ag2VO2PO4sub> batteries: the roles of composite electrode constituents on electrochemistry

    SciTech Connect

    Bock, David C.; Bruck, Andrea M.; Pelliccione, Christopher J.; Zhang, Yiman; Takeuchi, Kenneth J.; Marschilok, Amy C.; Takeuchi, Esther S.

    2016-11-01

    Silver vanadium phosphorous oxide, Ag2V2OPO4sub>, was used as a model system to systematically study the impact on the constituents of a composite electrode, including polymeric and conductive additives, on electrochemistry. Three different electrode compositions were investigated.

  14. Structure-dependent vibrational dynamics of Mg(BH 4sub> ) 2 polymorphs probed with neutron vibrational spectroscopy and first-principles calculations

    SciTech Connect

    Dimitrievska, Mirjana; White, James L.; Zhou, Wei; Stavila, Vitalie; Klebanoff, Leonard E.; Udovic, Terrence J.

    2016-08-19

    We investigated the structure-dependent vibrational properties of different Mg(BH4sub>)2 polymorphs (α, β, γ, and δ phases) with a combination of neutron vibrational spectroscopy (NVS) measurements and density functional theory (DFT) calculations, with emphasis placed on the effects of the local structure and orientation of the BH4sub>- anions. DFT simulations closely match the neutron vibrational spectra. The main bands in the low-energy region (20–80 meV) are associated with the BH4- librational modes. The features in the intermediate energy region (80–120 meV) are attributed to overtones and combination bands arising from the lower-energy modes. The features in the high-energy region (120–200 meV) correspond to the BH4sub>- symmetric and asymmetric bending vibrations, of which four peaks located at 140, 142, 160, and 172 meV are especially intense. There are noticeable intensity distribution variations in the vibrational bands for different polymorphs. We can explain these differences using the spatial distribution of BH4sub>- anions within various structures. An example of the possible identification of products after the hydrogenation of MgB2, using NVS measurements, is presented. Our results provide fundamental insights of benefit to researchers currently studying these promising hydrogen-storage materials.

  15. A new structure type of phosphate: Crystal structure of Na{sub 2}Zn{sub 5}(PO{sub 4}){sub 4}

    SciTech Connect

    Ji, L.N.; Ma, H.W. Li, J.B.; Liang, J.K.; Sun, B.J.; Liu, Y.H.; Zhang, J.Y.; Rao, G.H.

    2007-08-15

    A new compound, Na{sub 2}Zn{sub 5}(PO{sub 4}){sub 4}, was identified in the system ZnO-Na{sub 2}O-P{sub 2}O{sub 5} and high-quality crystal was obtained by the melt method. The crystal structure of this compound was solved by direct method from single crystal X-ray diffraction data. The structure was then refined anisotropically using a full-matrix least square refinement on F{sup 2} and the refinement converged to R{sub 1}=0.0233 and wR{sub 2}=0.0544. This compound crystallizes in the orthorhombic system with space group Pbcn, lattice parameters a=10.381(2) A, b=8.507(1) A, c=16.568(3) A and Z=4. The structure is made up of 3D [Zn{sub 5}P{sub 4}O{sub 16}]{sub n}{sup 2n-} covalent framework consisting of [Zn{sub 4}P{sub 4}O{sub 16}]{sub n}{sup 4n-} layers. The powder diffraction pattern of Na{sub 9}Zn{sub 21}(PO{sub 4}){sub 17} is explained by simulating a theoretical pattern with NaZnPO{sub 4} and Na{sub 2}Zn{sub 5}(PO{sub 4}){sub 4} in the molar ratio of 1:4 and then by Rietveld refinement of experimental pattern. Na{sub 2}Zn{sub 5}(PO{sub 4}){sub 4} melts congruently at 855 deg. C and its conductivity is 5.63x10{sup -9} S/cm. - Graphical abstract: Crystal structure and the relevant properties of Na{sub 2}Zn{sub 5}(PO{sub 4}){sub 4}, the first zincophosphate which having 3D [Zn{sub 5}P{sub 4}O{sub 16}]{sub n}{sup 2n-} covalent framework and the lowest P/Zn atomic ratio, were reported. The powder diffraction pattern of Na{sub 9}Zn{sub 21}(PO{sub 4}){sub 17} was proved to be a mixture of Na{sub 2}Zn{sub 5}(PO{sub 4}){sub 4} and NaZnPO{sub 4} in the molar ratio of 4:1 by Rietveld refinement.

  16. Pressure induced phase transformations in NaZr{sub 2}(PO{sub 4}){sub 3} studied by X-ray diffraction and Raman spectroscopy

    SciTech Connect

    Kamali, K.; Ravindran, T.R.; Chandra Shekar, N.V.; Pandey, K.K.; Sharma, S.M.

    2015-01-15

    Raman spectroscopic and x-ray diffraction measurements on NaZr{sub 2}(PO{sub 4}){sub 3} were carried out up to 30 GPa at close intervals of pressure, revealing two structural phase transformations around 5 and 6.6 GPa. The second phase at 5.4 GPa is indexed to R3 space group similar to that of RbTi{sub 2}(PO{sub 4}){sub 3}. Bulk modulus decreases abruptly from 53 GPa (B′=4) to 36 GPa (B′=4) in the second phase above 5 GPa. The structure of the phase III at 8.2 GPa is indexed as orthorhombic similar to the case of high temperature phase of monoclinic LiZr{sub 2}(PO{sub 4}){sub 3}. Bulk modulus of this phase III is found to be 65 GPa (B′=4), which is higher than that of the ambient phase. In high pressure Raman studies, modes corresponding to 72 and 112 cm{sup −1} soften in the ambient phase whereas around 5 GPa, the ones at 60, 105, 125 and 190 cm{sup −1} soften with pressure contributing negatively to overall thermal expansion. - Graphical abstract: High pressure study of NaZr{sub 2}(PO{sub 4}){sub 3} shows a reversible phase transition from R-3c to R3 structure at 5 GPa accompanied by an increase in compressibility signaling a polyhedral tilt transition. - Highlights: • NaZr{sub 2}(PO{sub 4}){sub 3} undergoes two reversible phase transitions at 5 and 6.7 GPa. • The transition at 5 is from rhombohedral R-3c to R3 structure. • Bulk modulus of NaZr{sub 2}(PO{sub 4}){sub 3} is lower than that for the isostructural RbTi{sub 2}(PO{sub 4}){sub 3.} • Compressibility increases with substitution of a smaller cation (Na). • Zr-translational and PO{sub 4} librational modes contribute to phase transition.

  17. Magnetic, Caloric and Crystallographic Properties of Dy5(SixGe1-x)4 sub> Alloys

    SciTech Connect

    Ivchenko, Vitaliy Vladislavovich

    2002-01-01

    Polycrystals of the intermetallic compound of the Dy5(SixGe1-x)4 sub> 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 Dy5(SixGe1-x)4 sub> 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 Gd5Si4sub>-type crystal structure: germanides in the composition range from 0 to 0.625 crystallize in the Sm5Ge4sub>-type structure, and alloys with intermediate composition range from 0.675 to 0.775 crystallize in the monoclinic Gd5Si2Ge2-type structure. The -ΔSm 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 Dy5(SixGe1-x)4 sub> system seems to be similar with those reported for the Gd5(SixGe1-x)4 sub> system. However, the interval and concentration range of three different phase regions in the Dy5(SixGe1-x)4 sub> 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 Dy5Si3Ge alloy exhibited FM phase transition below Curie temperature. A series of magnetic transitions were observed at low temperature in the Dy5(SixGe1-x

  18. A novel red long lasting phosphorescent (LLP) material {beta}-Zn{sub 3}(PO{sub 4}){sub 2}:Mn{sup 2+}, Sm{sup 3+}

    SciTech Connect

    Wang Jing; Su Qiang . E-mail: cessuq@zsu.edu.cn; Wang Shubin

    2005-04-20

    A novel red long lasting phosphorescent materials {beta}-Zn{sub 3}(PO{sub 4}){sub 2}:Mn{sup 2+},Sm{sup 3+} is firstly synthesized by high-temperature solid-state reaction. The influence of Sm{sup 3+} ions on luminescence and long lasting phosphorescence properties of Mn{sup 2+} in phosphor {beta}-Zn{sub 3}(PO{sub 4}){sub 2}:Mn{sup 2+},Sm{sup 3+} are systematically investigated. It is found that the red phosphorescence ({lambda} = 616 nm) performance of Mn{sup 2+} ion such as brightness and duration is largely improved when Sm{sup 3+} ion is co-doped into the matrix in which Mn{sup 2+} ion acts as luminescent center and Sm{sup 3+} ion plays an important role of electron trap. Thermoluminescence spectrums show that there exists one peak in {beta}-Zn{sub 3}(PO{sub 4}){sub 2}:Mn{sup 2+},Sm{sup 3+}, the depth of which is 0.33 eV, and that there are three peaks in {beta}-Zn{sub 3}(PO{sub 4}){sub 2}:Mn{sup 2+}, among which the depth of the lowest temperature peak in {beta}-Zn{sub 3}(PO{sub 4}){sub 2}:Mn{sup 2+} is 0.37 eV. Such differences in the trap depth result in the improvement of red long lasting phosphorescence of Mn{sup 2+} in present matrix.

  19. Thermoluminescence and glow curves analysis of γ-exposed Eu{sup 3+} doped K{sub 3}Y(PO{sub 4}){sub 2} nanophosphors

    SciTech Connect

    Gupta, Palvi; Bedyal, A.K.; Kumar, Vinay; Singh, Vivek K.; Khajuria, Y.; Ntwaeaborwa, O.M.; Swart, H.C.

    2016-01-15

    Highlights: • First time, a detailed comparative study of the glow curves and kinetic parameters was made on K{sub 3}Y(PO{sub 4}){sub 2} nanophosphor. • Combustion method was employed to synthesize the Eu{sup 3+} doped K{sub 3}Y(PO{sub 4}){sub 2} nanophosphor. • The nanophosphor exhibited sublinear response suggesting that it is suitable for TL dosimetry. - Abstract: Eu{sup 3+} doped K{sub 3}Y(PO{sub 4}){sub 2} nanophosphor was synthesized by combustion synthesis using urea as a fuel. The crystal structure and particle morphology of the nanophosphor were investigated by using X-ray diffraction and transmission electron microscopy, respectively. A Thermoluminescence (TL) study was carried out after exposing the samples to gamma radiation. The TL glow curves exhibited a prominent peak at 407 K and a small hump at 478 K. The intensity of the peaks increased with the increase in the dose of the gamma rays (0.01–5 kGy). The K{sub 3}Y(PO{sub 4}){sub 2}: Eu{sup 3+} (2.5 mol%) nanophosphor exhibited sublinear TL response to γ-radiation over a wide range of gamma doses (0.01–5 kGy). The TLanal program was used to analyze the glow curves of the K{sub 3}Y(PO{sub 4}){sub 2} nanophosphor at different doses (0.2–5 kGy) and different heating rates (3–10 K/s). A comparative study was done for kinetic trapping parameters that were determined by the peak shape methods of Chen, Grossweiner and Lushchik. The frequency factors (s) for each glow peak were also calculated. The values of the activation energy (E) obtained by the TLanal program were in good agreement with those obtained by the peak shape methods. The effect of different amount of doses and different heating rates are discussed.

  20. Syntheses, crystal structures and optical spectroscopy of Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) and Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O

    SciTech Connect

    Kazmierczak, Karolina; Hoeppe, Henning A.

    2011-05-15

    The lanthanide sulphate octahydrates Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) and the respective tetrahydrate Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O were obtained by evaporation of aqueous reaction mixtures of trivalent rare earth oxides and sulphuric acid at 300 K. Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) crystallise in space group C2/c (Z=4, a{sub Ho}=13.4421(4) A, b{sub Ho}=6.6745(2) A, c{sub Ho}=18.1642(5) A, {beta}{sub Ho}=102.006(1) A{sup 3} and a{sub Tm}=13.4118(14) A, b{sub Tm}=6.6402(6) A, c{sub Tm}=18.1040(16) A, {beta}{sub Tm}=101.980(8) A{sup 3}), Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O adopts space group P2{sub 1}/n (a=13.051(3) A, b=7.2047(14) A, c=13.316(3) A, {beta}=92.55(3) A{sup 3}). The vibrational and optical spectra of Ho{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O and Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O are also reported. -- Graphical abstract: In the lanthanide sulphate octahydrates the cations form slightly undulated layers. Between the layers are voids in which sulphate tetrahedra and water molecules are located. The holmium compound exhibits an Alexandrite effect. Display Omitted Highlights: {yields} Determination of the optimum conditions for the growth of single-crystals of Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) and Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O. {yields} Single-crystal structure elucidation of Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) including hydrogen bonds. {yields} Single-crystal structure determination of Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O including hydrogen bonds. {yields} UV-vis spectra of Ho{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O and Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O recorded and interpreted: Assignation of bands and clarification of the Alexandrite effect of the Ho compound. {yields} IR and Raman spectra of Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) and Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O recorded and interpreted.

  1. CARCINOGENICITY OF BROMODICHLOROMETHANE ADMINISTERED IN DRINKING WATER TO THE MALE F344/N RAT AND B6C3F, MOUSE

    EPA Science Inventory

    CARCINOGENICITY OF BROMODICHLOROMETHANE ADMINISTERED IN DRINKING WATER TO THE MALE F344/N RAT AND B6C3F1 MOUSE.

    Bromodichloromethane (BDCM) has been shown to produce kidney and large bowel tumors in both male and female F344/N rats, kidney tumors in male B6C3F 1 mice and ...

  2. Expression of human eukaryotic initiation factor 3f oscillates with cell cycle in A549 cells and is essential for cell viability

    PubMed Central

    2010-01-01

    Background Transcriptional and postranslational regulation of the cell cycle has been widely studied. However, there is scarce knowledge concerning translational control of this process. Several mammalian eukaryotic initiation factors (eIFs) seem to be implicated in controlling cell proliferation. In this work, we investigated if the human eIF3f expression and function is cell cycle related. Results The human eIF3f expression has been found to be upregulated in growth-stimulated A549 cells and downregulated in G0. Western blot analysis and eIF3f promotor-luciferase fusions revealed that eIF3f expression peaks twice in the cell cycle: in the S and the M phases. Deregulation of eIF3f expression negatively affects cell viability and induces apoptosis. Conclusions The expression pattern of human eIF3f during the cell cycle confirms that this gene is cell division related. The fact that eIF3f expression peaks in two cell cycle phases raises the possibility that this gene may exert a differential function in the S and M phases. Our results strongly suggest that eIF3f is essential for cell proliferation. PMID:20462454

  3. Structural study and physical properties of a new phosphate KCuFe(PO{sub 4}){sub 2}

    SciTech Connect

    Badri, Abdessalem; Hidouri, Mourad; Lopez, Maria Luisa; Pico, Carlos; Wattiaux, Alain; Ben Amara, Mongi

    2011-04-15

    Single crystals of a new phosphate KCuFe(PO{sub 4}){sub 2} have been prepared by the flux method and its structural and physical properties have been investigated. This compound crystallizes in the monoclinic system with the space group P2{sub 1}/n and its parameters are: a=7.958(3) A, b=9.931(2) A, c=9.039(2) A, {beta}=115.59(3){sup o} and Z=4. Its structure consists of FeO{sub 6} octahedra sharing corners with Cu{sub 2}O{sub 8} units of edge-sharing CuO{sub 5} polyhedra to form undulating chains extending infinitely along the b-axis. These chains are connected by the phosphate tetrahedra giving rise to a 3D framework with six-sided tunnels parallel to the [101] direction, where the K{sup +} ions are located. The Moessbauer spectroscopy results confirm the exclusive presence of octahedral Fe{sup 3+} ions. The magnetic measurements show the compound to be antiferromagnetic with C{sub m}=5.71 emu K/mol and {theta}=-156.5 K. The derived experimental effective moment {mu}{sub ex}=6.76{mu}{sub B} is somewhat higher than the theoretical one of {mu}{sub th}=6.16{mu}{sub B}, calculated taking only into account the spin contribution for Fe{sup 3+} and Cu{sup 2+} cations. Electrical measurements allow us to obtain the activation energy (1.22 eV) and the conductivity measurements suggest that the charge carriers through the structure are the potassium cations. -- Graphical abstract: A projection along the [101] direction of the structure showing the six-edged tunnels, occupied by the K{sup +} ions. Display Omitted Highlights: {yields} The reported structure is of a new type. {yields} The structural model is supported by a Moessbauer spectroscopy study. {yields} The magnetic susceptibility results are reported. {yields} The electrical properties are discussed.

  4. Combustion synthesized nanocrystalline Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C cathode for lithium-ion batteries

    SciTech Connect

    Nathiya, K.; Bhuvaneswari, D.; Gangulibabu; Kalaiselvi, N.

    2012-12-15

    Graphical abstract: Nanocrystalline Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C compound has been synthesized using a novel corn assisted combustion (CAC) method, wherein the composite prepared at 850 °C is found to exhibit superior physical and electrochemical properties than the one synthesized at 800 °C (Fig. 1). Despite the charge disproportionation of V{sup 4+} and a possible solid solution behavior of Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} cathode upon insertion and de-insertion of Li{sup +} ions, the structural stability of the same is appreciable, even with the extraction of third lithium at 4.6 V (Fig. 2). An appreciable specific capacity of 174 mAh g{sup −1} with an excellent columbic efficiency (99%) and better capacity retention upon high rate applications have been exhibited by Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C cathode, thus demonstrating the feasibility of CAC method in preparing the title compound to best suit with the needs of lithium battery applications. Display Omitted Highlights: ► Novel corn assisted combustion method has been used to synthesize Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C. ► Corn is a cheap and eco benign combustible fuel to facilitate CAC synthesis. ► Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C exhibits an appreciable specific capacity of 174 mAh g{sup −1} (C/10 rate). ► Currently observed columbic efficiency of 99% is better than the reported behavior. ► Suitability of Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C cathode up to 10C rate is demonstrated. -- Abstract: Nanocrystalline Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C composite synthesized using a novel corn assisted combustion method at 850 °C exhibits superior physical and electrochemical properties than the one synthesized at 800 °C. Despite the charge disproportionation of V{sup 4+} and a possible solid solution behavior of Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} cathode upon insertion and extraction of Li{sup +} ions, the structural stability of the same is appreciable, even with

  5. Topological amplitudes in D decays to two pseudoscalars: A global analysis with linear S U (3 )F breaking

    NASA Astrophysics Data System (ADS)

    Müller, Sarah; Nierste, Ulrich; Schacht, Stefan

    2015-07-01

    We study decays of D0, D+, and Ds+ mesons into two pseudoscalar mesons by expressing the decay amplitudes in terms of topological amplitudes. Including consistently S U (3 )F breaking to linear order, we show how the topological-amplitude decomposition can be mapped onto the standard expansion using reduced amplitudes characterized by S U (3 ) representations. The tree and annihilation amplitudes can be calculated in factorization up to corrections which are quadratic in the color-counting parameter 1 /Nc. We find new sum rules connecting D+→KSK+ , Ds+→KSπ+, and D+→K+π0, which test the quality of the 1 /Nc expansion. Subsequently, we determine the topological amplitudes in a global fit to the data, taking the statistical correlations among the various measurements into account. We carry out likelihood ratio tests in order to quantify the role of specific topological contributions. While the S U (3 )F limit is excluded with a significance of more than 5 standard deviations, a good fit (with Δ χ2<1 ) can be obtained with less than 28% of S U (3 )F breaking in the decay amplitudes. The magnitude of the penguin amplitude Pbreak, which probes the Glashow-Iliopoulos-Maiani mechanism, is consistent with zero; the hypothesis Pbreak=0 is rejected with a significance of just 0.7 σ . We obtain the Standard-Model correlation between B (D0→KLπ0) and B (D0→KSπ0), which probes doubly Cabibbo-suppressed amplitudes, and find that B (D0→KLπ0)

  6. Theoretical computation of thermophysical properties of high-temperature F2, CF4, C2F2, C2F4, C2F6, C3F6 and C3F8 plasmas

    NASA Astrophysics Data System (ADS)

    Wang, WeiZong; Wu, Yi; Rong, MingZhe; Éhn, László; Černušák, Ivan

    2012-07-01

    The calculated values of thermodynamic and transport properties of pure F2 and fluorocarbon compounds CF4, C2F2, C2F4, C2F6, C3F6 and C3F8 at high temperatures are presented in this paper. The thermodynamic properties are determined by the method of Gibbs free energy minimization, using standard thermodynamic tables. The transport properties, including electron diffusion coefficients, viscosity, thermal conductivity and electrical conductivity, are evaluated using the Chapman-Enskog method expanded up to the third-order approximation (second order for viscosity). The most accurate cross-section data that could be located are used to evaluate collision integrals. The calculations based on the assumption of local thermodynamic equilibrium are performed for atmospheric-pressure plasmas in the temperature range from 300 to 30 000 K for different pressures between 0.1 and 10 atm. The results of F2, CF4, C2F2, C2F4 and C2F6 are compared with those of previously published studies. Larger discrepancies occur for transport coefficients; these are explained in terms of the different values of the collision integrals that were used. The results presented here are expected to be more accurate because of the improved collision integrals employed.

  7. Multiple-site carcinogenicity of benzene in Fischer 344 rats and B6C3F sub 1 mice

    SciTech Connect

    Huff, J.E.; Haseman, J.K.; Eustis, S.; Maronpot, R.R. ); DeMarini, D.M. ); Peters, A.C.; Persing, R.L. ); Chrisp, C.E. ); Jacobs, A.C. )

    1989-07-01

    Toxicology and carcinogenesis studies of benzene were conducted in groups of 60 F344/N rats and 60 B6C3F{sub 1} mice of each sex for each of three exposure doses and vehicle controls. Using the results from 17-week studies, doses for the 2-year studies were selected based on clinical observations, on clinical pathologic findings and on body weight effects. Doses of 0, 50, 100, or 200 mg/kg body weight benzene in corn oil were administered by gavage to male rats, 5 days per week, for 103 weeks. Doses of 0, 25, 50, or 100 mg/kg benzene in corn oil were administered by gavage to female rats and to male and female mice for 103 weeks. Ten animals in each of the 16 groups were killed at 12 months, and necropsies were performed. Hematologic profiles were performed at 3-month intervals. For the 2-year studies, mean body weights of the top dose groups of male rats and of both sexes of mice were lower than those of the controls. Survivals of the top dose group of rats and mice of each sex were reduced; however, at week 92 for rats and week 91 for mice, survival was greater than 60% in all groups; most of the dosed animals that died before week 103 had neoplasia. Compound-related nonneoplastic or neoplastic effects on the hematopoietic system, Zymbal gland, forestomach, and adrenal gland were found both for rats and mice. Further, the oral cavity was affected in rats, and the lung, liver, Harderian gland, preputial gland, ovary, and mammary gland were affected in mice. Under the conditions of these 2-year gavage studies, there was clear evidence of carcinogenicity of benzene in male F344/N rats, female F344/N rats, male B6C3F{sub 1} mice, and female B6C3F{sub 1} mice. Dose-related lymphocytopenia was observed for male and female F344/N rats and male and female B6C3F{sub 1} mice. These unequivocal observations show clearly that benzene is a trans-species, trans-sex, multisite potent carcinogen.

  8. Development of doxorubicin-induced chronic cardiotoxicity in the B6C3F{sub 1} mouse model

    SciTech Connect

    Desai, Varsha G.; Herman, Eugene H.; Moland, Carrie L.; Branham, William S.; Lewis, Sherry M.; Davis, Kelly J.; George, Nysia I.; Lee, Taewon; Kerr, Susan; Fuscoe, James C.

    2013-01-01

    Serum levels of cardiac troponins serve as biomarkers of myocardial injury. However, troponins are released into the serum only after damage to cardiac tissue has occurred. Here, we report development of a mouse model of doxorubicin (DOX)-induced chronic cardiotoxicity to aid in the identification of predictive biomarkers of early events of cardiac tissue injury. Male B6C3F{sub 1} mice were administered intravenous DOX at 3 mg/kg body weight, or an equivalent volume of saline, once a week for 4, 6, 8, 10, 12, and 14 weeks, resulting in cumulative DOX doses of 12, 18, 24, 30, 36, and 42 mg/kg, respectively. Mice were sacrificed a week following the last dose. A significant reduction in body weight gain was observed in mice following exposure to a weekly DOX dose for 1 week and longer compared to saline-treated controls. DOX treatment also resulted in declines in red blood cell count, hemoglobin level, and hematocrit compared to saline-treated controls after the 2nd weekly dose until the 8th and 9th doses, followed by a modest recovery. All DOX-treated mice had significant elevations in cardiac troponin T concentrations in plasma compared to saline-treated controls, indicating cardiac tissue injury. Also, a dose-related increase in the severity of cardiac lesions was seen in mice exposed to 24 mg/kg DOX and higher cumulative doses. Mice treated with cumulative DOX doses of 30 mg/kg and higher showed a significant decline in heart rate, suggesting drug-induced cardiac dysfunction. Altogether, these findings demonstrate the development of DOX-induced chronic cardiotoxicity in B6C3F{sub 1} mice. -- Highlights: ► 24 mg/kg was a cumulative cardiotoxic dose of doxorubicin in male B6C3F{sub 1} mice. ► Doxorubicin-induced hematological toxicity was in association with splenomegaly. ► Doxorubicin induced severe testicular toxicity in B6C3F{sub 1} male mice.

  9. Endothelin-1 inhibits TNF alpha-induced iNOS expression in 3T3-F442A adipocytes.

    PubMed

    Mérial-Kieny, Christelle; Lonchampt, Michel; Cogé, Francis; Verwaerde, Patrick; Galizzi, Jean-Pierre; Boutin, Jean A; Lafontan, Max; Levens, Nigel; Galitzky, Jean; Félétou, Michel

    2003-07-01

    1. Endothelin-1 (ET-1) and tumor necrosis factor alpha (TNFalpha) by their action on adipocytes have been independently linked to the pathogenesis of insulino-resistance. In isolated adipocytes, TNFalpha induces the expression of the inducible nitric oxide synthase (iNOS). The purpose of the present work was, in the 3T3-F442A adipocyte cell line, to characterise TNFalpha-induced iNOS expression and to determine whether or not ET-1 could influence TNFalpha-induced iNOS expression and NO production. 2. In differentiated 3T3-F442A, treatment with TNFalpha (20 ng ml(-1)) induced the expression of a functional iNOS as demonstrated by nitrite assay, Western blot, reverse transcription-polymerase chain reaction and Northern blot analysis. TNFalpha-induced iNOS expression requires nuclear factor kappaB activation, but does not necessitate the activation of the PI-3 kinase/Akt and P38-MAP kinase pathways. 3. ET-1, but not ET-3, inhibited the TNFalpha-induced expression of iNOS protein and mRNA as well as nitrite production. The effects of ET-1 were blocked by a specific ETA (BQ123, pA(2) 7.4) but not by a specific ETB receptor antagonist (BQ788). 3T3-F442A adipocytes express the mRNAs for prepro-ET-1 and the ET-A receptor subtype, but not for the ET-B subtype. 4. The inhibitory effect of ET-1 was not affected by bisindolylmaleimide, SB 203580 or indomethacin, inhibitors of protein kinase C, p38-MAP kinase and cyclooxygenase, respectively, and was not associated with cAMP production. However, the effect of ET-1 was partially reversed by wortmannin, suggesting the involvement of PI3 kinase in the transduction signal of ET-1. 5. Differentiated 3T3-F442A adipocytes did not release ET-1 with or without exposure to TNFalpha, although the mRNA for preproET-1 was detected in both pre- and differentiated adipocytes. 6. Thus, these results confirm that adipocytes are a target for circulating ET-1 and demonstrate that the activation of the ETA receptor subtype can prevent TNFalpha

  10. Reattachment of Descemet's membrane using C3F8 gas in an eye with a Baerveldt aqueous shunt.

    PubMed

    Wimmersberger, Y; Bergin, C; Sharkawi, E

    2013-04-01

    Descemetʼs membrane detachment (DMD) is a rare complication following cataract and glaucoma surgery as well as lamellar graft procedures. DMD can lead to blurry vision, halos and severe visual loss. Clinically, when there is a large central detachment, a double anterior chamber is seen to form. In this scenario, surgical repair may be needed. Repair of localised DMD may be achieved by injection of gases such as perfluoropropane (C3F8) and sulfurhexafluoride (SF6) or sterile air. The effect of a functioning Baerveldt tube in situ during these injections has not been reported. We report a case of DMD repair in an eye with a Baerveldt aqueous shunt.

  11. Electron Scattering Processes from Plasma Processing Gases: CF3I, C3F8 and C4F8

    NASA Astrophysics Data System (ADS)

    Kimura, Mineo

    2000-10-01

    Brief review of the current level of understanding of electron scattering processes from plasma processing gases such as CF3I, C3F8 and C4F8 will be presented. Experimental as well as theoretical studies for these gases have been carried out last a few years by several groups, and although the amount of cross-section data is still far from sufficient, we are able to establish the data set for some processes in these gases. I will briefly discuss possible next-generation processing gases.

  12. Intense Mirror-Less Pulsed Far-Infrared CH3F Emission Pumped with a TEA CO2 Laser

    NASA Astrophysics Data System (ADS)

    Liu, Chuang; Qu, Yanchen; Zhao, Weijiang; Zhang, Ruiliang

    2015-06-01

    An efficient pulsed CH3F mirror-less cavity is presented. The output energy of the 192 μm far-infrared emission is studied as a function of gas pressure, cell length, and the pump intensity. Maximum pulse energy of 0.4 mJ is achieved from a 185-cm long gas cell at 6 Torr, and the photon conversion efficiency is 2.5 %. Characteristics of this mirror-less system and possibilities for higher output energy are also discussed.

  13. Alluaudite Na 2 Co 2 Fe(PO 4sub> ) 3 as an electroactive material for sodium ion batteries

    SciTech Connect

    Essehli, R.; Belharouak, I.; Ben Yahia, H.; Maher, K.; Abouimrane, A.; Orayech, B.; Calder, S.; Zhou, X. L.; Zhou, Z.; Sun, Y-K.

    2015-03-23

    The electroactive orthophosphate Na2Co2Fe(PO4sub>)(3) was synthesized using a solid state reaction. Its crystal structure was solved using the combination of powder X-ray-and neutron-diffraction data. This material crystallizes according to the alluaudite structure (S.G. C2/c). The structure consists of edge sharing [MO6] octahedra (M = Fe, Co) resulting in chains parallel to [-101]. These chains are linked together via the [PO4sub>] tetrahedra to form two distinct tunnels in which sodium cations are located. The electrochemical properties of Na2Co2Fe(PO4sub>)(3) were evaluated by galvanostatic charge-discharge cycling. During the first discharge to 0.03 V, Na2Co2Fe(PO4sub>)(3) delivers a specific capacity of 604 mA h g(-1). This capacity is equivalent to the reaction of more than seven sodium ions per formula unit. Hence, this is a strong indication of a conversion-type reaction with the formation of metallic Fe and Co. The subsequent charge and discharge involved the reaction of fewer Na ions as expected for a conversion reaction. When discharged to 0.9 V, the material intercalated only one Na+-ion leading to the formation of a new phase Na3Co2Fe(PO4sub>)(3). This phase could then be cycled reversibly with an average voltage of 3.6 V vs. Na+/Na and a capacity of 110 mA h g(-1). This result is in good agreement with the theoretical capacity expected from the extraction/insertion of two sodium atoms in Na2Co2Fe(PO4sub>)(3).

  14. A{sub 5}RE{sub 4}X[TO{sub 4}]{sub 4} crystal growth: Fluoride flux synthesis of Na{sub 5}Ln{sub 4}F[GeO{sub 4}]{sub 4} (Ln=Pr, Nd), the first quaternary germanate oxyfluorides

    SciTech Connect

    Latshaw, Allison M.; Wilkins, Branford O.; Morrison, Gregory; Smith, Mark D.; Loye, Hans-Conrad zur

    2016-07-15

    Crystals of Na{sub 5}Pr{sub 4}F[GeO{sub 4}]{sub 4} and Na{sub 5}Nd{sub 4}F[GeO{sub 4}]{sub 4} were synthesized using a eutectic sodium fluoride, sodium chloride flux. Both compounds crystallize in the tetragonal space group I-4 with lattice parameters of a=12.1173(4) Å and c=5.6795(2) Å (Pr) and of a=12.0642(17) Å and c=5.6674(11) Å (Nd). The structure of the reported compounds is three-dimensional with face and corner sharing lanthanide polyhedra which edge and corner share with isolated germanium tetrahedra. These novel compositions represent the first example of quaternary germanium containing oxyfluorides. - Graphical abstract: Structural image of the first examples of quaternary germanate oxyfluorides. Display Omitted - Highlights: • Molten flux growth of crystals of two lanthanide germanate oxyfluorides. • Expansion of the A{sub 5}RE{sub 4}X[TO{sub 4}]{sub 4} family into germanate oxyfluorides. • Synthesis of Na{sub 5}Nd{sub 4}F[GeO{sub 4}]{sub 4} and Na{sub 5}Pr{sub 4}F[GeO{sub 4}]{sub 4}.

  15. Ultrafast bulk diffusion of AlHx in high-entropy dehydrogenation intermediates of NaAlH4sub> [Highly mobile AlHx species and the dehydogenation kinetics of NaAlH4sub>

    SciTech Connect

    Zhang, Feng; Wood, Brandon C.; Wang, Yan; Wang, Cai -Zhuang; Ho, Kai -Ming; Chou, Mei -Yin

    2014-07-21

    Using first-principles molecular dynamics (FPMD) and total-energy calculations, we demonstrate low-barrier bulk diffusion of Al-bearing species in γ-NaAlH4sub>, a recently proposed high-entropy polymorph of NaAlH4sub>. For charged AlH4sub>– and neutral AlH3 vacancies, the computed barriers for diffusion are <0.1 eV, and we directly observe the predicted diffusive pathways in FPMD simulations at picosecond time scales. In contrast, such diffusion in the α phase is inaccessible to FPMD, consistent with much higher barriers. The transport behavior of γ-NaAlH4sub>, in addition to key dynamical and structural signatures, is consistent with experimental observations of high-mobility species, strongly supporting the idea that an intermediate transition from the α phase to a high-entropy polymorph facilitates the hydrogen-releasing decomposition of NaAlH4. Lastly, our results provide an answer to longstanding questions regarding the responsible agent for the experimentally observed efficient Al transport during dehydrogenation and suggest that mass transport and phase transformation kinetics are coupled. Implications for understanding the (de)hydrogenation of undoped and catalyzed NaAlH4sub> are discussed.

  16. Different Mutagenic Potential of HIV-1 Restriction Factors APOBEC3G and APOBEC3F Is Determined by Distinct Single-Stranded DNA Scanning Mechanisms

    PubMed Central

    Ara, Anjuman; Love, Robin P.; Chelico, Linda

    2014-01-01

    The APOBEC3 deoxycytidine deaminase family functions as host restriction factors that can block replication of Vif (virus infectivity factor) deficient HIV-1 virions to differing degrees by deaminating cytosines to uracils in single-stranded (−)HIV-1 DNA. Upon replication of the (−)DNA to (+)DNA, the HIV-1 reverse transcriptase incorporates adenines opposite the uracils, thereby inducing C/G→T/A mutations that can functionally inactivate HIV-1. Although both APOBEC3F and APOBEC3G are expressed in cell types HIV-1 infects and are suppressed by Vif, there has been no prior biochemical analysis of APOBEC3F, in contrast to APOBEC3G. Using synthetic DNA substrates, we characterized APOBEC3F and found that similar to APOBEC3G; it is a processive enzyme and can deaminate at least two cytosines in a single enzyme-substrate encounter. However, APOBEC3F scanning movement is distinct from APOBEC3G, and relies on jumping rather than both jumping and sliding. APOBEC3F jumping movements were also different from APOBEC3G. The lack of sliding movement from APOBEC3F is due to an 190NPM192 motif, since insertion of this motif into APOBEC3G decreases its sliding movements. The APOBEC3G NPM mutant induced significantly less mutations in comparison to wild-type APOBEC3G in an in vitro model HIV-1 replication assay and single-cycle infectivity assay, indicating that differences in DNA scanning were relevant to restriction of HIV-1. Conversely, mutation of the APOBEC3F 191Pro to 191Gly enables APOBEC3F sliding movements to occur. Although APOBEC3F 190NGM192 could slide, the enzyme did not induce more mutagenesis than wild-type APOBEC3F, demonstrating that the unique jumping mechanism of APOBEC3F abrogates the influence of sliding on mutagenesis. Overall, we demonstrate key differences in the impact of APOBEC3F- and APOBEC3G-induced mutagenesis on HIV-1 that supports a model in which both the processive DNA scanning mechanism and preferred deamination motif (APOBEC3F, 5

  17. Age-specific absolute and relative organ weight distributions for B6C3F1 mice.

    PubMed

    Marino, Dale J

    2012-01-01

    The B6C3F1 mouse is the standard mouse strain used in toxicology studies conducted by the National Cancer Institute (NCI) and the National Toxicology Program (NTP). While numerous reports have been published on growth, survival, and tumor incidence, no overall compilation of organ weight data is available. Importantly, organ weight change is an endpoint used by regulatory agencies to develop toxicity reference values (TRVs) for use in human health risk assessments. Furthermore, physiologically based pharmacokinetic (PBPK) models, which utilize relative organ weights, are increasingly being used to develop TRVs. Therefore, all available absolute and relative organ weight data for untreated control B6C3F1 mice were collected from NCI/NTP studies in order to develop age-specific distributions. Results show that organ weights were collected more frequently in NCI/NTP studies at 2-wk (60 studies), 3-mo (147 studies), and 15-mo (40 studies) intervals than at other intervals, and more frequently from feeding and inhalation than drinking water studies. Liver, right kidney, lung, heart, thymus, and brain weights were most frequently collected. From the collected data, the mean and standard deviation for absolute and relative organ weights were calculated. Results show age-related increases in absolute liver, right kidney, lung, and heart weights and relatively stable brain and right testis weights. The results suggest a general variability trend in absolute organ weights of brain < right testis < right kidney < heart < liver < lung < spleen < thymus. This report describes the results of this effort.

  18. Immunomodulatory activity of orphan drug Elmiron® in female B6C3F1/N mice

    PubMed Central

    Thakur, Sheetal A.; Nyska, Abraham; White, Kimber L.; Smith, Matthew J.; Auttachoat, Wimolnut; Germolec, Dori R.

    2014-01-01

    Interstitial cystitis (IC) is a chronic disorder characterized by bladder discomfort and urinary urgency in the absence of identifiable infection. Despite the expanding use in treatment of IC and other chronic conditions, the effects of Elmiron® treatment on immune system remain unknown. Therefore, female B6C3F1/N mice were orally administered Elmiron® daily for 28-days at doses of 63, 125, 250, 500 or 1000 mg/kg to evaluate its immunomodulatory effects. Mice treated with Elmiron® had a significant increase in absolute numbers of splenic macrophages (63, 500 and 1000 mg/kg) and natural killer (NK) cells (250 and 1000 mg/kg). Elmiron® treatment did not affect the humoral immune response or T cell proliferative response. However, innate immune responses such as phagocytosis by liver macrophages (1000 mg/kg) and NK cell activity were enhanced (500 and 1000 mg/kg). Further analysis using a disease resistance model showed that Elmiron® -treated mice demonstrated significantly increased anti-tumor activity against B16F10 melanoma cells at the 500 and 1000 mg/kg doses. Collectively, we conclude that Elmiron® administration stimulates the immune system, increasing numbers of specific cell populations and enhancing macrophage phagocytosis and NK cell activity in female B6C3F1/N mice. This augmentation may have largely contributed to the reduced number of B16F10 melanoma tumors. PMID:24657363

  19. Near-ultraviolet lateral photovoltaic effect in Fe3O4sub>/3C-SiC Schottky junctions.

    PubMed

    Song, Bingqian; Wang, Xianjie; Li, Bo; Zhang, Lingli; Lv, Zhe; Zhang, Yu; Wang, Yang; Tang, Jinke; Xu, Ping; Li, Bingsheng; Yang, Yanqiang; Sui, Yu; Song, Bo

    2016-10-17

    In this paper, we report a sensitive lateral photovoltaic effect (LPE) in Fe3O4sub>/3C-SiC Schottky junctions with a fast relaxation time at near-ultraviolet wavelengths. The rectifying behavior suggests that the large build-in electric field was formed in the Schottky junctions. This device has excellent position sensitivity as high as 67.8 mV mm-1 illuminated by a 405 nm laser. The optical relaxation time of the LPE is about 30 μs. The fast relaxation and high positional sensitivity of the LPE make the Fe3O4sub>/3C-SiC junction a promising candidate for a wide range of ultraviolet/near-ultraviolet optoelectronic applications.

  20. Anisotropy of an acousto-optic figure of merit for NaBi(MoO4sub>)2 crystals.

    PubMed

    Mys, Oksana; Krupych, Oleh; Vlokh, Rostyslav

    2016-10-01

    We develop a technique for analyzing the anisotropy of an acousto-optic figure of merit for crystals belonging to tetragonal symmetry groups 4/m, 4, and 4¯. The technique is based on phenomenological relations that describe anisotropies of the effective elasto-optic coefficients and the acoustic wave velocities. Our approach is verified on the example of NaBi(MoO4sub>)2 crystals for all possible types and geometries of acousto-optic interactions. We list and characterize the acousto-optic interaction geometries at which the maximal acousto-optic figures of merit are reached for both isotropic and anisotropic interaction types. Finally, we show that the acousto-optic efficiency of NaBi(MoO4sub>)2 originates mainly from large elasto-optic coefficients.

  1. Sequential energy transfer up-conversion process in Yb3+/Er3+:SrMoO4sub> crystal.

    PubMed

    Zhuang, Renzhong; Wang, Guofu

    2016-04-04

    This paper reports the dynamic characteristics of sequential energy transfer up-conversion processes in Yb3+/Er3+:SrMoO4sub> crystal. A general method based on the emission intensity has been developed to calculate the nonradiative decay rate. A new macroscopic theory has been developed to calculate the energy transfer parameters based on the crystal structure. According to both new calculating methods, the spectral parameters of Yb3+/Er3+:SrMoO4sub> crystal were calculated, such as up-conversion luminescent quantum efficiencies and threshold pump powers. Both calculating methods may be applied to calculate the spectral parameters of the laser crystal materials.

  2. Robust diamond-like Fe-Si network in the zero-strain NaxFeSiO4sub> cathode

    SciTech Connect

    Ye, Zhuo; Zhao, Xin; Li, Shouding; Wu, Shunqing; Wu, Ping; Nguyen, Manh Cuong; Guo, Jianghuai; Mi, Jinxiao; Gong, Zhengliang; Zhu, Zi -Zhong; Yang, Yong; Wang, Cai -Zhuang; Ho, Kai -Ming

    2016-07-14

    Sodium orthosilicates Na2MSiO4sub> (M denotes transition metals) have attracted much attention due to the possibility of exchanging two electrons per formula unit. In this work, we report a group of sodium iron orthosilicates Na2FeSiO4sub>. Their crystal structures are characterized by a diamond-like Fe-Si network. The Fe-Si network is quite robust against the charge/discharge process, which explains the high structural stability observed in experiment. Furthermore, using the density functional theory within the GGA + U framework and X-ray diffraction studies, the crystal structures and structural stabilities during the sodium extraction/re-insertion process are systematically investigated.

  3. Strong lattice correlation of non-equilibrium quasiparticles in a pseudospin-1/2 Mott insulator Sr2IrO4sub>

    SciTech Connect

    Li, Yuelin; Schaller, Richard D.; Zhu, Mengze; Walko, Donald A.; Kim, Jungho; Ke, Xianglin; Miao, Ludi; Mao, Z. Q.

    2016-01-20

    In correlated oxides the coupling of quasiparticles to other degrees of freedom such as spin and lattice plays critical roles in the emergence of symmetry-breaking quantum ordered states such as high temperature superconductivity. We report a strong lattice coupling of photon-induced quasiparticles in spin-orbital coupling Mott insulator Sr2IrO4sub> probed via optical excitation. Combining time-resolved x-ray diffraction and optical spectroscopy techniques, we reconstruct a spatiotemporal map of the diffusion of these quasiparticles. Lastly, due to the unique electronic configuration of the quasiparticles, the strong lattice correlation is unexpected but extends the similarity between Sr2IrO4sub> and cuprates to a new dimension of electron-phonon coupling which persists under highly non-equilibrium conditions.

  4. Theoretical Assessment on the Phase Transformation Kinetic Pathways of Multi-component Ti Alloys: Application to Ti-6Al-4sub>V

    SciTech Connect

    Ji, Yanzhou; Heo, Tae Wook; Zhang, Fan; Chen, Long-Qing

    2015-12-21

    Here we present our theoretical assessment of the kinetic pathways during phase transformations of multi-component Ti alloys. Employing the graphical thermodynamic approach and an integrated free energy function based on the realistic thermodynamic database and assuming that a displacive structural transformation occurs much faster than long-range diffusional processes, we analyze the phase stabilities of Ti-6Al-4sub>V (Ti-6wt.%Al-4sub>wt.%V). Our systematic analyses predict a variety of possible kinetic pathways for β to (α + β) transformations leading to different types of microstructures under various heat treatment conditions. In addition, the possibility of unconventional kinetic pathways is discussed. Lastly, we also briefly discuss the application of our approach to general multicomponent/multiphase alloy systems.

  5. Magnetic properties of (FeIn{sub 2}S{sub 4}){sub 1-x}(In{sub 2}S{sub 3}){sub x} alloy single crystals

    SciTech Connect

    Bodnar, I. V. Novikova, M. A.; Trukhanov, S. V.

    2013-05-15

    (FeIn{sub 2}S{sub 4}){sub 1-x}(In{sub 2}S{sub 3}){sub x} alloy single crystals are grown by oriented crystallization in the entire range of component concentrations. For the single crystals, studies of the magnetic properties are carried out in the temperature range 4-300 K and the magnetic-field range 0-14 T. It is established that almost all of the alloys are paramagnetic materials at temperatures down to the lowest achievable temperatures ({approx}4 K). It is shown that the ground magnetic phase state of the alloys is the spin-glass state with the freezing temperature steadily increasing with increasing Fe{sup 2+} cation content. The most probable causes and mechanism of formation of the magnetic state of the (FeIn{sub 2}S{sub 4}){sub 1-x}(In{sub 2}S{sub 3}){sub x} crystals are discussed.

  6. Structure symmetry determination and magnetic evolution in Sr2Ir1–xRhxO4sub>

    SciTech Connect

    Ye, Feng; Wang, Xiaoping; Hoffmann, Christina; Wang, Jinchen; Chi, Songxue; Matsuda, Masaaki; Chakoumakos, Bryan C.; Fernandez-Baca, Jaime A.; Cao, Gang

    2015-11-23

    We use single-crystal neutron diffraction to determine the crystal structure symmetry and to study the magnetic evolution in the rhodium doped iridates Sr2Ir1–xRhxO4sub> (0 ≤ x ≤ 0.16). Throughout this doping range, the crystal structure retains a tetragonal symmetry (space group I4<sub>1/a) with two distinct magnetic Ir sites in the unit cell forming staggered IrO6 rotation. Upon Rh doping, the magnetic order is suppressed and the magnetic moment of Ir4+ is reduced from 0.21 μB/Ir for x = 0 to 0.18 μB/Ir for x = 0.12. As a result, the magnetic structure at x = 0.12 is different from that of the parent compound while the moments remain in the basal plane.

  7. Structurally induced magnetization in a La2/3Sr4/3MnO4sub> superlattice

    SciTech Connect

    Shah, Amish B.; Nelson-Cheeseman, Brittany B.; Subramanian, Ganesh; Bhattacharya, Anand; Spence, John C.H.

    2012-03-16

    A structural transition has been observed in a digital superlattice of La2/3Sr4/3MnO4sub>, which is correlated to a magnetization enhancement upon cooling the sample. The artificial superlattices were grown layer-by-layer using ozone-assisted molecular beam epitaxy (MBE). Electron diffraction experiments show a phase transition below 150K in nanopatches of the superlattice, which coincides with an enhanced magnetization starting below 110K. Furthermore, atomic scale electron energy loss spectroscopy (EELS) shows changes in the Mn L2,3 and O K edges, which are related to valence, strain, and the atomic coordination within nanopatches. Atomic resolution image and EELS showing variations of oxygen and lanthanum signature edges in a La2/3Sr4/3MnO4sub> supperlattice.

  8. Neutron scattering studies of the H2a-H2b and (H3-H4)/sub 2/ histone complexes

    SciTech Connect

    Carlson, R.D.

    1982-01-01

    Neutron scattering experiments have shown that both the (H3-H4)/sub 2/ and H2a-H2b histone complexes are quite asymmetric in solution. The (H3-H4)/sub 2/ tetramer is an oblate or flattened structure, with a radius of gyration almost as large as that of the core octamer. If the tetramer is primarily globular, it must have an axial ratio of about 1:5. It is more likely, however, that this asymmetry results in part from N-terminal arms that extend outward approximately within the major plane of the particle. If this is the case, less asymmetric models for the globular part of the tetramer, including a dislocated disk, can be made consistent with the scattering data. The H2a-H2b dimer, on the other hand, is an elongated structure. 48 references, 12 figures, 1 table.

  9. Structural phase transition and phonon instability in Cu12Sb4sub>S13

    SciTech Connect

    May, Andrew F.; Delaire, Olivier A.; Niedziela, Jennifer L.; Lara-Curzio, Edgar; Susner, Michael A.; Abernathy, Douglas L.; Kirkham, Melanie J.; McGuire, Michael A.

    2016-02-08

    In this study, a structural phase transition has been discovered in the synthetic tetrahedrite Cu12Sb4sub>S13 at approximately 88 K. Upon cooling, the material transforms from its known cubic symmetry to a tetragonal unit cell that is characterized by an in-plane ordering that leads to a doubling of the unit cell volume. Specific heat capacity measurements demonstrate a hysteresis of more than two degrees in the associated anomaly. A similar hysteresis was observed in powder x-ray diffraction measurements, which also indicate a coexistence of the two phases, and together these results suggest a first-order transition. This structural transition coincides with a recently-reported metal-insulator transition, and the structural instability is related to the very low thermal conductivity κ in these materials. Inelastic neutron scattering was used to measure the phonon density of states in Cu12Sb4sub>S13 and Cu10Zn2Sb4sub>S13, both of which possess a localized, low-energy phonon mode associated with strongly anharmonic copper displacements that suppress κ. In Cu12Sb4sub>S13, signatures of the phase transition are observed in the temperature dependence of the localized mode, which disappears at the structural transition. In contrast, in the cubic Zn-doped material, the mode is at slightly higher-energy but observable for all temperatures, though it softens upon cooling.

  10. Multi-wavelength Yb:YAG/Nd3+:YVO4sub> continuous-wave microchip Raman laser.

    PubMed

    Wang, Xiao-Lei; Dong, Jun; Wang, Xiao-Jie; Xu, Jie; Ueda, Ken-Ichi; Kaminskii, Alexander A

    2016-08-01

    Multi-wavelength continuous-wave (CW) Raman lasers in a laser diode pumped Yb:YAG/Nd3+:YVO4sub> microchip Raman laser have been demonstrated for the first time to our best knowledge. The multi-wavelength laser of the first Stokes radiation around 1.08 μm has been achieved with a Raman shift of 261  cm-1 for a-cut Nd:YVO4sub> crystal corresponding to the fundamental wavelength at 1.05 μm. Multi-wavelength laser operation simultaneously around 1.05 and 1.08 μm has been achieved under the incident pump power between 1.5 and 1.7 W. Multi-wavelength Raman laser with frequency separation of 1 THz around 1.08 μm has been obtained when the incident pump power is higher than 1.7 W. The maximum Raman laser output power of 260 mW at 1.08 μm is obtained and the corresponding optical-to-optical conversion efficiency is 4.2%. Elliptically polarized fundamental laser and linearly polarized Raman laser were observed in an Yb:YAG/Nd:YVO4sub> CW microchip Raman laser. The experimental results of linearly polarized, multi-wavelength Yb:YAG/Nd:YVO4sub> CW microchip Raman laser with adjustable frequency separation provide a novel approach for developing potential compact laser sources for Terahertz generation.

  11. Li/Ag2VO2PO4sub> batteries: the roles of composite electrode constituents on electrochemistry

    SciTech Connect

    Bock, David C.; Bruck, Andrea M.; Pelliccione, Christopher J.; Zhang, Yiman; Takeuchi, Kenneth J.; Marschilok, Amy C.; Takeuchi, Esther S.

    2016-11-01

    In this study, we utilize silver vanadium phosphorous oxide, Ag2VO2PO4sub>, as a model system to systematically study the impact of the constituents of a composite electrode, including polymeric and conductive additives, on electrochemistry. Notably, although highly resistive, this bimetallic cathode can be discharged as a pure electroactive material in the absence of a conductive additive as it generates an in situ conductive matrix via a reduction displacement reaction resulting in the formation of silver metal nanoparticles. Also, three different electrode compositions were investigated: Ag2VO2PO4sub> only, Ag2VO2PO4sub>4 with binder, and Ag2VO2PO4sub> with binder and carbon. Constant current discharge, pulse testing and impedance spectroscopy measurements were used to characterize the electrochemical properties of the electrodes as a function of depth of discharge. In situ EDXRD was used to spatially resolve the discharge progression within the cathode by following the formation of Ag0. Ex situ XRD and EXAFS modeling were used to quantify the amount of Ag0 formed. Results indicate that the metal center reduced (V5+ or Ag+) was highly dependent on composite composition (presence of PTFE, carbon), depth of discharge (Ag0 nanoparticle formation), and spatial location within the cathode. The addition of a binder was found to increase cell polarization, and the percolation network provided by the carbon in the presence of PTFE was further increased with reduction and formation of Ag0. Lastly, this study provides insight into the factors controlling the electrochemistry of resistive active materials in composite electrodes.

  12. Lasing properties of sodium-gadolinium tungstate NaGd(WO{sub 4}){sub 2} crystals doped with Tm{sup 3+} ions

    SciTech Connect

    Zharikov, Evgeny V; Lis, Denis A; Popov, A V; Subbotin, Kirill A; Ushakov, S N; Shestakov, A V; Razdobreev, I M

    2006-06-30

    Lasing is obtained in Tm{sup 3+}-doped sodium-gadolinium tungstate NaGd(WO{sub 4}){sub 2} crystals longitudinally pumped by pulses from a laser diode bar. The slope lasing efficiency is 16%. Lasing was observed at wavelengths of 1957, 1944, 1936, and 1901 nm for the transmission coefficients of the output mirror T{sub out} = 0.3%, 1.4%, 3.3%, and 8.5%, respectively. (lasers)

  13. Magnetic excitations in the spin-1/2 triangular-lattice antiferromagnet Cs2CuBr4sub>

    SciTech Connect

    Zvyagin, S. A.; Ozerov, M.; Kamenskyi, D.; Wosnitza, J.; Krzystek, J.; Yoshizawa, D.; Hagiwara, M.; Hu, Rongwei; Ryu, Hyejin; Petrovic, C.; Zhitomirsky, M. E.

    2015-11-27

    We present on high- field electron spin resonance (ESR) studies of magnetic excitations in the spin- 1/2 triangular-lattice antiferromagnet Cs2CuBr4sub>. Frequency- field diagrams of ESR excitations are measured for different orientations of magnetic fields up to 25 T. We show that the substantial zero- field energy gap, Δ ≈ 9.5 K, observed in the low-temperature excitation spectrum of Cs2CuBr4sub> [Zvyagin et al:, Phys. Rev. Lett. 112, 077206 (2014)], is present well above TN. Noticeably, the transition into the long-range magnetically ordered phase does not significantly affect the size of the gap, suggesting that even below TN the high-energy spin dynamics in Cs2CuBr4sub> is determined by short-range-order spin correlations. The experimental data are compared with results of model spin-wave-theory calculations for spin-1/2 triangle-lattice antiferromagnet.

  14. Synthesis, crystal growth, structural and magnetic characterization of NH4sub>MCl2(HCOO), M=(Fe, Co, Ni)

    SciTech Connect

    Greenfield, Joshua T.; Ovidiu Garlea, V.; Kamali, Saeed; Chen, Michael; Kovnir, Kirill

    2015-09-24

    In this paper, an ambient-pressure solution route and an improved solvothermal synthetic method have been developed to produce polycrystalline powders and large single crystals of NH4sub>MCl2(HCOO) (M=Fe, Co, Ni). The magnetic structure of the 1D linear chain compound NH4sub>FeCl2(HCOO) has been determined by low-temperature neutron powder diffraction, revealing ferromagnetic intra-chain interactions and antiferromagnetic inter-chain interactions. Finally, the newly-reported Co and Ni analogs are isostructural with NH4sub>FeCl2(HCOO), but there are significant differences in the magnetic properties of each compound; the Ni analog behaves similarly to the Fe compound but with stronger magnetic coupling, exhibiting antiferromagnetic ordering (TN=8.5 K) and a broad metamagnetic transition between 2 and 5 T, while the Co analog does not order magnetically above 2 K, despite strong antiferromagnetic nearest-neighbor interactions.

  15. Unravelling the low thermal expansion coefficient of cation-substituted YBaCo4sub>O7+δ

    SciTech Connect

    Manthiram, Arumugam; Huq, Ashfia; Kan, Wang Hay; Lai, Ke -Yu

    2016-01-12

    With an aim to understand the origin of the low thermal expansion coefficients (TECs), cation substituted YBaCo4sub>O7-type oxides have been investigated by in-situ neutron diffraction, bond valence sum (BVS), thermogravimetric analysis, and dilatometry. The compositions YBaCo4sub>O7+δ, Y0.9ln0.1BaCo3ZnO7+δ, and Y0.9ln0.1BaCo3Zn0.6Fe0.4sub>O7+δ) were synthesized by solid-state reaction at 1200 °C. Here, Rietveld refinement of the joint synchrotron X-ray and neutron diffraction data shows that the Zn and Fe dopants have different preferences to substitute the Co ions in the 6c and 2a sites.

  16. New insulating antiferromagnetic quaternary iridates MLa10Ir4sub>O24 (M=Sr, Ba)

    SciTech Connect

    Zhao, Qingbiao; Han, Fei; Stoumpos, Constantinos C.; Han, Tian -Heng; Li, Hao; Mitchell, J. F.

    2015-07-01

    Recently, oxides of Ir4+ have received renewed attention in the condensed matter physics community, as it has been reported that certain iridates have a strongly spin-orbital coupled (SOC) electronic state, Jeff = ½, that defines the electronic and magnetic properties. The canonical example is the Ruddlesden-Popper compound Sr2IrO4sub>, which has been suggested as a potential route to a new class of high temperature superconductor due to the formal analogy between Jeff = ½ and the S = ½ state of the cuprate superconductors. The quest for other iridium oxides that present tests of the underlying SOC physics is underway. In this spirit, here we report the synthesis and physical properties of two new quaternary tetravalent iridates, MLa10Ir4sub>O24 (M = Sr, Ba). The crystal structure of both compounds features isolated IrO6 octahedra in which the electronic configuration of Ir is d5. As a result, both compounds order antiferromagnetically despite the lack of obvious superexchange pathways, and resistivity measurement shows that SrLa10Ir4sub>O24 is an insulator.

  17. Crystal structure, IR and Mössbauer spectroscopy and magnetic properties of KZnFe(PO{sub 4}){sub 2} related to the zeolite-ABW-like compounds

    SciTech Connect

    Badri, Abdessalem; Hidouri, Mourad; Wattiaux, Alain; López, María Luisa; Veiga, María Luisa; Amara, Mongi Ben

    2014-07-01

    Highlights: • The reported structure of KZnFe(PO{sub 4}){sub 2} is closely related to the zeolite ABW-type. • The structure is described in detail. • The IR and Mössbauer spectroscopy results are reported. • The magnetic properties are developed. - Abstract: The new iron phosphate KZnFe(PO{sub 4}){sub 2} has been synthesized by flux method and solid state reaction, and characterized by X-ray diffraction, IR, Mössbauer spectroscopy and magnetic susceptibility. This compound crystallizes in the monoclinic space group C2/c with the cell parameters: a = 13.514(4) Å, b = 13.273(6) Å, c = 8.742(3) Å and β = 100.07(2)°. It displays strong similarities with the phosphates KCoAl(PO{sub 4}){sub 2} and NaCoPO{sub 4} and features some analogies with the zeolite-ABW structural type. 3D framework is built up by a corner-sharing between MO{sub 4} (M = 0.5 Zn + 0.5 Fe) and PO{sub 4} tetrahedra. The K{sup +} ions are found within crossing tunnels perpendicular to the (1 0 0), (0 1 0) and (0 0 1) planes, delimited by this framework. A Mössbauer study confirmed the presence of Fe{sup 3+} ions in a tetrahedral environment. Magnetic measurements revealed an antiferromagnetic behavior with T{sub N} = 8.5 K.

  18. Energetics of a uranothorite (Th1–xUxSiO4sub>) solid solution

    SciTech Connect

    Guo, Xiaofeng; Szenknect, Stephanie; Wu, Di; Xu, Hongwu; Dacheux, Nicolas; Navrotsky, Alexandra

    2016-10-11

    High-temperature oxide melt solution calorimetric measurements were completed to determine the enthalpies of formation of the uranothorite, (USiO4sub>)x–(ThSiO4sub>)1–x, solid solution. Phase-pure samples with x values of 0, 0.11, 0.21, 0.35, 0.71, and 0.84 were prepared, purified, and characterized by powder X-ray diffraction, electron probe microanalysis, thermogravimetric analysis and differential scanning calorimetry coupled with in situ mass spectrometry, and high-temperature oxide melt solution calorimetry. This work confirms the energetic metastability of coffinite, USiO4sub>, and U-rich intermediate silicate phases with respect to a mixture of binary oxides. Furthermore, variations in unit cell parameters and negative excess volumes of mixing, coupled with strongly exothermic enthalpies of mixing in the solid solution, suggest short-range cation ordering that can stabilize intermediate compositions, especially near x = 0.5.

  19. Nanosized pure and Cr doped Al{sub 2−x}Sc{sub x}(WO{sub 4}){sub 3} solid solutions

    SciTech Connect

    Yordanova, A.; Koseva, I.; Velichkova, N.; Kovacheva, D.; Rabadjieva, D.; Nikolov, V.

    2012-06-15

    Highlights: ► Nanosized pure and Cr-doped Al{sub 2−x}Sc{sub x}(WO{sub 4}){sub 3} obtained for a first time. ► Material for ceramics with different application. ► Co-precipitation method for preparation. ► X-ray, DTA, TEM investigations. ► Co-precipitation method gives 10–70 nm particles. -- Abstract: Nanosized solid solutions of the formula Al{sub 2−x−y}Sc{sub x}Cr{sub y}(WO{sub 4}){sub 3}, where x varies from 0 to 2 and y from 0.02 to 0.1 are synthesized for the first time by the co-precipitation method. X-ray powder diffraction, DTA/TG and TEM analyses demonstrate that the powders are pure solid solution compounds with orthorhombic structure, space group Pnca. Particle sizes between 10 and 70 nm are obtained after thermal treatment of the precipitates at 550 °C for 1 h for all compositions except in the case of Sc{sub 1.9}Cr{sub 0.1}(WO{sub 4}){sub 3}. For the last one mean particle size of 64 nm was obtained after thermal treatment at 500 °C. The influence of the concentrations of Sc and Cr as well as of the temperature and duration of the thermal treatment on the particle size and size distribution are established and discussed.

  20. The role of the CeO 2 /BiVO 4sub> interface in optimized Fe–Ce oxide coatings for solar fuels photoanodes

    SciTech Connect

    Shinde, A.; Li, G.; Zhou, L.; Guevarra, D.; Suram, S. K.; Toma, F. M.; Yan, Q.; Haber, J. A.; Neaton, J. B.; Gregoire, J. M.

    2016-09-09

    Solar fuel generators entail a high degree of materials integration, and efficient photoelectrocatalysis of the constituent reactions hinges upon the establishment of highly functional interfaces. Our recent application of high throughput experimentation to interface discovery for solar fuels photoanodes has revealed several surprising and promising mixed-metal oxide coatings for BiVO4sub>. Furthermore, when using sputter deposition of composition and thickness gradients on a uniform BiVO4sub> film, we systematically explore photoanodic performance as a function of the composition and loading of Fe–Ce oxide coatings. This combinatorial materials integration study not only enhances the performance of this new class of materials but also identifies CeO2 as a critical ingredient that merits detailed study. A heteroepitaxial CeO2(001)/BiVO4(010) interface is identified in which Bi and V remain fully coordinated to O such that no surface states are formed. Ab initio calculations of the integrated materials and inspection of the electronic structure reveals mechanisms by which CeO2 facilitates charge transport while mitigating deleterious recombination. Our results support the observations that addition of Ce to BiVO4sub> coatings greatly enhances photoelectrocatalytic activity, providing an important strategy for developing a scalable solar fuels technology.

  1. Organogold oligomers: Exploiting iClick and aurophilic cluster formation to prepare solution stable Au4sub> repeating units

    SciTech Connect

    Yang, Xi; Wang, Shanshan; Ghiviriga, Ion; Abboud, Khalil A.; Veige, Adam S.

    2015-05-19

    A novel synthetic method to create gold based metallo–oligomers/polymers via the combination of inorganic click (iClick) with intermolecular aurophilic interactions is demonstrated. Complexes [PEt3Au]4sub>(μ-N3C2C6H5) (1) and [PPhMe2Au]4sub (μ-N3C2C6H5) (2) and {[PEt3Au]4sub>[(μ-N3C2)2-9,9-dihexyl-9H-fluorene]}n (8) have been synthesized via iClick. The tetranuclear structures of 1 and 2, induced by aurophilic bonding, are confirmed in the solid state through single crystal X-ray diffraction experiments and in solution via variable temperature NMR spectroscopy. The extended 1D structure of 8 is constructed by aurophilic induced self-assembly. 1H DOSY NMR analysis reveals that the aurophilic bonds in 1, 2, and 8 are retained in the solution phase. The degree of polymerization within complex 8 is temperature and concentration dependent, as determined by 1H DOSY NMR. The complex 8 is a rare example of a solution stable higher ordered structure linked by aurophilic interactions.

  2. The Electrochemistry of Fe 3 O 4sub> /Polypyrrole Composite Electrodes in Lithium-Ion Cells: The Role of Polypyrrole in Capacity Retention

    SciTech Connect

    Bruck, Andrea M.; Gannett, Cara N.; Bock, David C.; Smith, Paul F.; Marschilok, Amy C.; Takeuchi, Kenneth J.; Takeuchi, Esther S.

    2016-12-15

    In two series of magnetite (Fe3O4) composite electrodes, one group with and one group without added carbon, containing varying quantities of polypyrrole (PPy), and a non-conductive polyvinylidene difluoride (PVDF) binder were constructed and then analyzed using electrochemical and spectroscopic techniques. Galvanostatic cycling and alternating current (AC) impedance measurements were used in tandem to measure delivered capacity, capacity retention, and the related impedance at various stages of discharge and charge. Further, the reversibility of Fe3O4sub> to iron metal (Fe0) conversion observed during discharge was quantitatively assessed ex-situ using X-ray Absorption Spectroscopy (XAS). The Fe3O4sub> composite containing the largest weight fraction of PPy (20 wt%) with added carbon demonstrated reduced irreversible capacity on initial cycles and improved cycling stability over 50 cycles, attributed to decreased reaction with the electrolyte in the presence of PPy. Our study illustrated the beneficial role of PPy addition to Fe3O4sub> based electrodes was not strongly related to improved electrical conductivity, but rather to improved ion transport related to the formation of a more favorable surface electrolyte interphase (SEI).

  3. Structural and magnetic characterization of the one-dimensional S = 5/2 antiferromagnetic chain system SrMn(VO4sub>)(OH)

    SciTech Connect

    Sanjeewa, Liurukara D.; Garlea, Vasile O.; McGuire, Michael A.; McMillen, Colin D.; Cao, Huibo; Kolis, Joseph W.

    2016-06-06

    The descloizite-type compound, SrMn(VO4sub>)(OH), was synthesized as large single crystals (1-2mm) using a high-temperature high-pressure hydrothermal technique. X-ray single crystal structure analysis reveals that the material crystallizes in the acentric orthorhombic space group of P212121 (no. 19), Z = 4. The structure exhibits a one-dimensional feature, with [MnO4sub>] chains propagating along the a-axis which are interconnected by VO4sub> tetrahedra. Raman and infrared spectra were obtained to identify the fundamental vanadate and hydroxide vibrational modes. Magnetization data reveal a broad maximum at approximately 80 K, arising from one-dimensional magnetic correlations with intrachain exchange constant of J/kB = 9.97(3) K between nearest Mn neighbors and a canted antiferromagnetic behavior below TN = 30 K. Single crystal neutron diffraction at 4 K yielded a magnetic structure solution in the lower symmetry of the magnetic space group P21 with two unique chains displaying antiferromagnetically ordered Mn moments oriented nearly perpendicular to the chain axis. Lastly, the presence of the Dzyaloshinskii Moriya antisymmetric exchange interaction leads to a slight canting of the spins and gives rise to a weak ferromagnetic component along the chain direction.

  4. Correlation of anisotropy and directional conduction in β-Li3PS4sub> fast Li+ conductor

    SciTech Connect

    Chen, Yan; Cai, Lu; Liu, Zengcai; dela Cruz, Clarina R.; Liang, Chengdu; An, Ke

    2015-07-06

    Our letter reports the correlation of anisotropy and directional conduction in the fast Li+ conductor β-Li3PS4sub>, one of the low-symmetry crystalline electrolyte candidates. The material has both high conductivity and good stability that serves well for the large-scale energy storage applications of all-solid-state lithium ion batteries. The anisotropic physical properties, demonstrated here by the thermal expansion coefficients, are crucial for compatibility in the solid-state system and battery performance. Neutron and X-ray powder diffraction measurements were done to determine the crystal structure and thermal stability. Moreover, the crystallographic b-axis was revealed as a fast expansion direction, while negligible thermal expansion was observed along the a-axis around the battery operating temperatures. The anisotropic behavior has its structural origin from the Li+ conduction channels with incomplete Li occupancy and a flexible connection of LiS4sub> and PS4sub> tetrahedra within the framework. This indicates a strong correlation in the direction of the ionic transport in the low-symmetry Li+ conductor.

  5. Multiple-site carcinogenicity of benzene in Fischer 344 rats and B6C3F1 mice.

    PubMed Central

    Huff, J E; Haseman, J K; DeMarini, D M; Eustis, S; Maronpot, R R; Peters, A C; Persing, R L; Chrisp, C E; Jacobs, A C

    1989-01-01

    Toxicology and carcinogenesis studies of benzene (CAS No. 71-43-2; greater than 99.7% pure) were conducted in groups of 60 F344/N rats and 60 B6C3F1 mice of each sex for each of three exposure doses and vehicle controls. These composite studies on benzene were designed and conducted because of large production volume and widespread human exposure, because of the epidemiologic association with leukemia, and because previous experiments were considered inadequate or inconclusive for determining carcinogenicity in laboratory animals. Using the results from 17-week studies, doses for the 2-year studies were selected based on clinical observations (tremors in higher dosed mice), on clinical pathologic findings (lymphoid depletion in rats and leukopenia in mice), and on body weight effects. Doses of 0, 50, 100, or 200 mg/kg body weight benzene in corn oil were administered by gavage to male rats, 5 days per week, for 103 weeks. Doses of 0, 25, 50, or 100 mg/kg benzene in corn oil were administered by gavage to female rats and to male and female mice for 103 weeks. Ten animals in each of the 16 groups were killed at 12 months, and necropsies were performed. Hematologic profiles were performed at 3-month intervals. For the 2-year studies, mean body weights of the top dose groups of male rats and of both sexes of mice were lower than those of the controls. Survivals of the top dose group of rats and mice of each sex were reduced; however, at week 92 for rats and week 91 for mice, survival was greater than 60% in all groups; most of the dosed animals that died before week 103 had neoplasia. Compound-related nonneoplastic or neoplastic effects on the hematopoietic system, Zymbal gland, forestomach, and adrenal gland were found both for rats and mice. Further, the oral cavity was affected in rats, and the lung, liver, Harderian gland, preputial gland, ovary, and mammary gland were affected in mice. Under the conditions of these 2-year gavage studies, there was clear evidence

  6. Genistein modulation of streptozotocin diabetes in male B6C3F1 mice can be induced by diet

    SciTech Connect

    Guo, Tai L.; Wang, Yunbiao; Xiong, Tao; Ling, Xiao; Zheng, Jianfeng

    2014-11-01

    Diet and phytoestrogens affect the development and progression of diabetes. The objective of the present study was to determine if oral exposure to phytoestrogen genistein (GE) by gavage changed blood glucose levels (BGL) through immunomodulation in streptozotocin (STZ)-induced diabetic male B6C3F1 mice fed with three different diets. These three diets were: NTP-2000 diet (NTP), soy- and alfalfa-free 5K96 diet (SOF) and high fat diet (HFD) with 60% of kcal from fat, primarily rendered fat of swine. The dosing regimen for STZ consisted of three 100 mg/kg doses (i.p.): the first dose was administered at approximately 2 weeks following the initiation of daily GE (20 mg/kg) gavage, and the second dose was on day 19 following the first dose, and the third dose was on day 57 following the first dose. In mice on the NTP diet, GE treatment decreased BGL with statistical significances observed on days 33 and 82 following the first STZ injection. In mice fed the HFD diet, GE treatment produced a significant decrease and a significant increase in BGL on days 15 and 89 following the first STZ injection, respectively. In mice fed the SOF diet, GE treatment had no significant effects on BGL. Although GE treatment affected phenotypic distributions of both splenocytes (T cells, B cells, natural killer cells and neutrophils) and thymocytes (CD4/CD8 and CD44/CD25), and their mitochondrial transmembrane potential and generation of reactive oxygen species, indicators of cell death (possibly apoptosis), GE modulation of neutrophils was more consistent with its diabetogenic or anti-diabetic potentials. The differential effects of GE on BGL in male B6C3F1 mice fed with three different diets with varied phytoestrogen contents suggest that the estrogenic properties of this compound may contribute to its modulation of diabetes. - Highlights: • Diets affected streptozotocin-induced diabetes in male B6C3F1 mice. • Genistein modulation of streptozotocin diabetes can be induced by diet.

  7. Anomalous Hall hysteresis in T m3F e5O12/Pt with strain-induced perpendicular magnetic anisotropy

    NASA Astrophysics Data System (ADS)

    Tang, Chi; Sellappan, Pathikumar; Liu, Yawen; Xu, Yadong; Garay, Javier E.; Shi, Jing

    2016-10-01

    We demonstrate robust interface strain-induced perpendicular magnetic anisotropy in atomically flat ferrimagnetic insulator T m3F e5O12 (TIG) films grown with pulsed laser deposition on a substituted G d3G a5O12 substrate which maximizes the tensile strain at the interface. In bilayers consisting of Pt and TIG, we observe large squared Hall hysteresis loops over a wide range of thicknesses of Pt at room temperature. When a thin Cu layer is inserted between Pt and TIG, the Hall hysteresis magnitude decays but stays finite as the thickness of Cu increases up to 5 nm. However, if the Cu layer is placed atop Pt instead, the Hall hysteresis magnitude is consistently larger than when the Cu layer with the same thickness is inserted in between for all Cu thicknesses. These results suggest that both the proximity-induced ferromagnetism and spin current contribute to the anomalous Hall effect.

  8. Experimental and theoretical methods to study structural phase transition mechanisms in K3WO3F3 oxyfluoride

    NASA Astrophysics Data System (ADS)

    Krylov, A. S.; Sofronova, S. N.; Kolesnikova, E. M.; Ivanov, Yu. N.; Sukhovsky, A. A.; Goryainov, S. V.; Ivanenko, A. A.; Shestakov, N. P.; Kocharova, A. G.; Vtyurin, A. N.

    2014-10-01

    The results of structural phase transitions mechanisms study in K3WO3F3oxyfluoride are represented by different experimental and theoretical methods. The structural phase transition anomalies at T1=452 K and T2=414 K of Raman and IR spectra have been analyzed. Using vibrational spectroscopy methods, the NMR-experiment has been done to clarify the nature of found phase transitions: displacive types or order-disorder types. The model of “disordered” crystal was proposed, and the results of lattice dynamics calculation in frameworks of the generalized Gordon-Kim method of ordered (R3) and “disordered” crystals were compared. The high pressure phases were studied by the Raman technique too.

  9. Coexistence of ferromagnetism and superconductivity in CeO_{0.3}F_{0.7}BiS_{2}

    SciTech Connect

    Lee, Jooseop; Demura, S; Stone, Matthew B; Iida, Kazuki; Ehlers, Georg; Dela Cruz, Clarina R; Matsuda, Masaaki; Deguchi, K; Mizuguchi, Y; Miura, O; Louca, Despina; Lee, Seung-Hun

    2014-01-01

    Bulk magnetization, transport and neutron scattering measurements were performed to investigate the electronic and magnetic properties of a polycrystalline sample of the newly discovered ferromagnetic superconductor, CeO0:3F0:7BiS2. Ferromagnetism develops below TFM = 6.54(8) K and superconductivity is found to coexist with the ferromagnetic state below TSC 4.5 K. Inelastic neutron scattering measurements reveal a very weakly dispersive magnetic excitation at 1.8 meV that can be explained by an Ising-like spin Hamiltonian. Under application of an external magnetic eld, the direction of the magnetic moment changes from the c-axis to the ab-plane and the 1.8 meV excitation splits into two modes. A possible mechanism for the unusual magnetism and its relation to superconductivity is discussed.

  10. The CH3CHOO 'Criegee intermediate' and its anion: Isomers, infrared spectra, and W3-F12 energetics

    NASA Astrophysics Data System (ADS)

    Kettner, M.; Karton, A.; McKinley, A. J.; Wild, D. A.

    2015-02-01

    For the CH3CHOO Criegee intermediates (ethanal-oxide) and analogous anions, we obtain heats of formations and electron affinities at CCSDT(Q)/CBS level of theory by means of the high-level W3-F12 thermochemical protocol. The electron affinities amount to 0.20 eV and 0.35 eV for the cis and trans isomer, respectively. Neutral cis and trans isomers are separated by 14.1 kJ/mol, the anions are almost isoenergetic (0.4 kJ/mol separation). Harmonic vibrational frequencies are presented at CCSD(T)/aug'-cc-pVTZ level of theory. Since the synthesis of these species in gas-phase experiments might be possible in the near future, we include a predicted photoelectron spectrum.

  11. Total and differential cross sections of C3H8 and C3F8 by electron and positron impacts

    NASA Astrophysics Data System (ADS)

    Sueoka, Osamu; Kitajima, Masashi; Sakamoto, Y.; Suzuki, T.; Samukawa, S.; Sueoka, Osamu; Hamada, Akira; Kimura, Mineo

    1998-10-01

    Total and differential elastic cross sections in e-/e+ + C3H8 and C3F8 scattering have been investigated experimentally and theoretically. The differential cross section measurement by electron impact has been carried out from 2 eV to 100 eV, while the total cross section measurement by electron and positron has been for 0.7 eV to 600 eV. The theoretical study has been performed by using the continuum multiple-scattering method. The present total cross sections are found to agree reasonably well with those by Wayne State Univ. group, and theoretical rationale for origins of shape resonances are provided.

  12. Unexpected metal ion-assisted transformations leading to unexplored bridging ligands in Ni(II) coordination chemistry: the case of PO3F(2-) group.

    PubMed

    Dermitzaki, Despina; Raptopoulou, Catherine P; Psycharis, Vassilis; Escuer, Albert; Perlepes, Spyros P; Stamatatos, Theocharis C

    2014-10-21

    The initial 'accidental', metal ion-assisted hydrolysis of PF6(-) to PO3F(2-) has been evolved in a systematic investigation of the bridging affinity of the latter group in Ni(II)/oximate chemistry; mono-, di- and trinuclear complexes have been prepared and confirmed both the rich reactivity of PO3F(2-) and its potential for further use as bridging ligand in high-nuclearity 3d-metal cluster chemistry.

  13. Tumultuous relationship between the human immunodeficiency virus type 1 viral infectivity factor (Vif) and the human APOBEC-3G and APOBEC-3F restriction factors.

    PubMed

    Henriet, Simon; Mercenne, Gaëlle; Bernacchi, Serena; Paillart, Jean-Christophe; Marquet, Roland

    2009-06-01

    The viral infectivity factor (Vif) is dispensable for human immunodeficiency virus type 1 (HIV-1) replication in so-called permissive cells but is required for replication in nonpermissive cell lines and for pathogenesis. Virions produced in the absence of Vif have an aberrant morphology and an unstable core and are unable to complete reverse transcription. Recent studies demonstrated that human APOBEC-3G (hA3G) and APOBEC-3F (hA3F), which are selectively expressed in nonpermissive cells, possess strong anti-HIV-1 activity and are sufficient to confer a nonpermissive phenotype. Vif induces the degradation of hA3G and hA3F, suggesting that its main function is to counteract these cellular factors. Most studies focused on the hypermutation induced by the cytidine deaminase activity of hA3G and hA3F and on their Vif-induced degradation by the proteasome. However, recent studies suggested that several mechanisms are involved both in the antiviral activity of hA3G and hA3F and in the way Vif counteracts these antiviral factors. Attempts to reconcile the studies involving Vif in virus assembly and stability with these recent findings suggest that hA3G and hA3F partially exert their antiviral activity independently of their catalytic activity by destabilizing the viral core and the reverse transcription complex, possibly by interfering with the assembly and/or maturation of the viral particles. Vif could then counteract hA3G and hA3F by excluding them from the viral assembly intermediates through competition for the viral genomic RNA, by regulating the proteolytic processing of Pr55(Gag), by enhancing the efficiency of the reverse transcription process, and by inhibiting the enzymatic activities of hA3G and hA3F.

  14. Exploration on anion ordering, optical properties and electronic structure in K{sub 3}WO{sub 3}F{sub 3} elpasolite

    SciTech Connect

    Atuchin, V.V.; Isaenko, L.I.; Kesler, V.G.; Lin, Z.S.; Molokeev, M.S.; Yelisseyev, A.P.; Zhurkov, S.A.

    2012-03-15

    Room-temperature modification of potassium oxyfluorotungstate, G2-K{sub 3}WO{sub 3}F{sub 3}, has been prepared by low-temperature chemical route and single crystal growth. Wide optical transparency range of 0.3-9.4 {mu}m and forbidden band gap E{sub g}=4.32 eV have been obtained for G2-K{sub 3}WO{sub 3}F{sub 3} crystal. Meanwhile, its electronic structure has been calculated with the first-principles calculations. The good agreement between the theorectical and experimental results have been achieved. Furthermore, G2-K{sub 3}WO{sub 3}F{sub 3} is predicted to possess the relatively large nonlinear optical coefficients. - Graphical abstract: Using the cm-size K{sub 3}WO{sub 3}F{sub 3} crystal (left upper), the transmission spectrum (right upper) and XPS valence electronic states (left lower) were measured, agreed with the ab initio results (right lower). Highlights: Black-Right-Pointing-Pointer The cm-size G2-K{sub 3}WO{sub 3}F{sub 3} single crystals are obtained. Black-Right-Pointing-Pointer Optical absorption edge and transmission range are defined for G2-K{sub 3}WO{sub 3}F{sub 3} crystal. Black-Right-Pointing-Pointer Crystal structures of all known K{sub 3}WO{sub 3}F{sub 3} polymorph modifications are determined. Black-Right-Pointing-Pointer Experimental electronic structure is consistent with the first-principles result. Black-Right-Pointing-Pointer G2-K{sub 3}WO{sub 3}F{sub 3} is predicted as a crystal with large NLO coefficients.

  15. Carcinogenicity of malachite green chloride and leucomalachite green in B6C3F1 mice and F344 rats.

    PubMed

    Culp, Sandra J; Mellick, Paul W; Trotter, Ronald W; Greenlees, Kevin J; Kodell, Ralph L; Beland, Frederick A

    2006-08-01

    Malachite green is a triphenylmethane dye used in the fish industry as an anti-fungal agent. Leucomalachite green is formed by the metabolic reduction of malachite green and persists in the tissues of exposed fish. In this study, we examined the carcinogenicity of malachite green chloride and leucomalachite green. Female F344 rats (48 per group) were fed diets containing 0, 100, 300, or 600 ppm malachite green chloride for 104 weeks, at which time the extent of tumorigenesis was assessed. Additional groups of 48 female and 48 male F344 rats were fed diets containing 0, 91, 272, or 543 ppm leucomalachite green for 104 weeks. Groups of 48 female B6C3F1 mice were fed diets containing 0, 100, 225, or 450 ppm malachite green chloride or 0, 91, 204, or 408 ppm leucomalachite green for 104 weeks. For each of the exposures, food consumption in the treatment groups was similar to the controls. Rats fed malachite green chloride or leucomalachite green had dose-dependent reductions in body weight; in mice, there were no consistent effects upon body weights with either compound. Female rats exposed to malachite green chloride had increased incidences of thyroid gland follicular cell adenoma or carcinoma and hepatocellular adenoma, and a dose-related increasing trend in mammary gland carcinoma. Female rats fed malachite green chloride and female and male rats fed leucomalachite green had a dose-related decreasing trend in the incidence of mononuclear cell leukemia. In male rats fed leucomalachite green there was a decreasing trend in pituitary gland adenoma and an increasing trend in interstitial cell adenoma of the testis. There were no treatment-related neoplasms in female B6C3F1 mice fed malachite green chloride. Female mice fed leucomalachite green had a dose-related increasing trend in the incidence of hepatocellular adenoma or carcinoma, with the incidence being significant in the highest dose group.

  16. NOKOMIS 3-F4

    EPA Pesticide Factsheets

    Technical product bulletin: this dispersant used in oil spill cleanups may be applied directly from drums by fitting them with a T connection and pumping fresh or salt water across the junction, which pulls dispersant into water stream and onto spill.

  17. The retroviral hypermutation specificity of APOBEC3F and APOBEC3G is governed by the C-terminal DNA cytosine deaminase domain.

    PubMed

    Haché, Guylaine; Liddament, Mark T; Harris, Reuben S

    2005-03-25

    The human proteins APOBEC3F and APOBEC3G restrict retroviral infection by deaminating cytosine residues in the first cDNA strand of a replicating virus. These proteins have two putative deaminase domains, and it is unclear whether one or both catalyze deamination, unlike their homologs, AID and APOBEC1, which are well characterized single domain deaminases. Here, we show that only the C-terminal cytosine deaminase domain of APOBEC3F and -3G governs retroviral hypermutation. A chimeric protein with the N-terminal cytosine deaminase domain from APOBEC3G and the C-terminal cytosine deaminase domain from APOBEC3F elicited a dinucleotide hypermutation preference nearly indistinguishable from that of APOBEC3F. This 5'-TC-->TT mutational specificity was confirmed in a heterologous Escherichia coli-based mutation assay, in which the 5'-CC-->CT dinucleotide hypermutation preference of APOBEC3G also mapped to the C-terminal deaminase domain. An N-terminal APOBEC3G deletion mutant displayed a preference indistinguishable from that of the full-length protein, and replacing the C-terminal deaminase domain of APOBEC3F with AID resulted in an AID-like mutational signature. Together, these data indicate that only the C-terminal domain of APOBEC3F and -3G dictates the retroviral minus strand 5'-TC and 5'-CC dinucleotide hypermutation preferences, respectively, leaving the N-terminal domain to perform other aspects of retroviral restriction.

  18. The mechanism of the area negative thermal expansion in KBe{sub 2}BO{sub 3}F{sub 2} family crystals: A first-principles study

    SciTech Connect

    Jiang, Xingxing; Molokeev, Maxim S.; Li, Wei; Wu, Shaofan; Lin, Zheshuai Wu, Yicheng; Chen, Chuangtian

    2016-02-07

    A very recent study demonstrated that the KBe{sub 2}BO{sub 3}F{sub 2} (KBBF) family of crystals, including KBBF, RbBe{sub 2}BO{sub 3}F{sub 2}, and CsBe{sub 2}BO{sub 3}F{sub 2}, are the only known borates exhibiting a rarely occurring isotropic area negative thermal expansion (NTE) behavior, over a very large temperature range. In the present work, the NTE mechanism in these crystals is comprehensively investigated using the first-principles calculations. It is revealed that the area NTE behavior mainly originates from the concerted distortion of [BeO{sub 3}F] tetrahedra in the two-dimensional [Be{sub 2}BO{sub 3}F{sub 2}]{sub ∞} framework with respect to temperature, while the [BO{sub 3}] triangles remain almost rigid. Moreover, the different magnitude of NTE effect in the three crystals is attributed to the interaction difference between the alkali metal atoms (K, Rb, or Cs) and the [Be{sub 2}BO{sub 3}F{sub 2}]{sub ∞} layer.

  19. Structural, electronic and thermodynamic properties of britholites Ca{sub 10−x}La{sub x}(PO{sub 4}){sub 6−x}(SiO{sub 4}){sub x}F{sub 2} (0 ≤ x ≤ 6): Experiment and theory

    SciTech Connect

    Njema, H.; Debbichi, M.; Boughzala, K.; Said, M.; Bouzouita, K.

    2014-03-01

    Highlights: • The structural and electronic properties of apatites with the general formula Ca{sub 10−x}La{sub x}(PO{sub 4}){sub 6−x}(SiO{sub 4}){sub x}F{sub 2} (0 ≤ x ≤ 6) have been investigated by means of the density functional theory. • The calculated enthalpy of formation of the compounds increased with the substitution degree. • The decrease in stability is probably due to the disorder induced in the Ca/LaO{sub 6}F polyhedron, following the substitution. - Abstract: The apatite-type compounds Ca{sub 10−x}La{sub x}(PO{sub 4}){sub 6−x}(SiO{sub 4}){sub x}F{sub 2} with 0 ≤ x ≤ 6 were prepared using a high temperature solid state reaction and were characterized by X-ray diffraction. The crystal structure, chemical bonding, electronic structure and formation energy of all relaxed structures were analyzed by density functional theory (DFT). The calculated results show that the predicted geometry can well reproduce the structural parameters. The incorporation of La{sup 3+} into the fluorapatite (FA) structure induced especially at the level of the S(2) sites a certain disorder which is responsible for the weakening in the stability with x. Excellent agreement were obtained between the calculated and experimental results. Moreover, the band structure indicates that despite the reduction of the band gap with x content all materials remain insulating.

  20. X-ray spectroscopic characterization of Co(IV) and metal–metal interactions in Co4sub>O4sub>: Electronic structure contributions to the formation of high-valent states relevant to the oxygen evolution reaction

    SciTech Connect

    Hadt, Ryan G.; Hayes, Dugan; Brodsky, Casey N.; Ullman, Andrew M.; Casa, Diego M.; Upton, Mary H.; Nocera, Daniel G.; Chen, Lin X.

    2016-08-12

    In this paper, the formation of high-valent states is a key factor in making highly active transition metal-based catalysts of the oxygen-evolving reaction (OER). These high oxidation states will be strongly influenced by the local geometric and electronic structures of the metal ion, which is difficult to study due to spectroscopically active and complex backgrounds, short lifetimes, and limited concentrations. Here, we use a wide range of complementary X-ray spectroscopies coupled to DFT calculations to study Co4sub>O4sub> cubanes, which provide insight into the high-valent Co(IV) centers responsible for the activity of molecular and heterogeneous OER catalysts. The combination of X-ray absorption and 1s3p resonant inelastic X-ray scattering (Kβ RIXS) allow Co(IV) to be isolated and studied against a spectroscopically active Co(III) background. Co K- and L-edge X-ray absorption data allow for a detailed characterization of the 3d-manifold of effectively localized Co(IV) centers and provide a direct handle on the ligand field environment and covalency of the t2g-based redox active molecular orbital. Kβ RIXS is also shown to provide a powerful probe of Co(IV), and specific spectral features are sensitive to the degree of oxo-mediated metal-metal coupling across Co4sub>O4sub>. Guided by the data, calculations show electron-hole delocalization can actually oppose Co(IV) formation. Computational extension of Co4sub>O4sub> to CoM3O4sub> structures (M = redox-inactive metal) defines electronic structure contri-butions to Co(IV) formation. Redox activity is shown to be linearly related to covalency, and M(III) oxo inductive effects on Co(IV) oxo bonding can tune the covalency of high-valent sites over a large range and thereby tune E0 over hundreds of mVs.

  1. Infrared and Raman spectra of Na{sub 2}Cu(SO{sub 4}){sub 2}{center_dot}2H{sub 2}O and (CH{sub 3}NH{sub 3}){sub 2}M(II)(SO{sub 4}){sub 2}{center_dot}6H{sub 2}O with M(II) = Cu, Zn, and Ni

    SciTech Connect

    Pillai, V.P.M.; Nayar, V.U.; Jordanovska, V.B.

    1997-11-01

    FTIR and Raman spectra of Na{sub 2}Cu(SO{sub 4}){sub 2}{center_dot}2H{sub 2}O and (CH{sub 3}NH{sub 3}){sub 2}M(II) (SO{sub 4}){sub 2}{center_dot}6H{sub 2}O with M(II) = Cu, Zn, and Ni are recorded and analyzed. Bands are assigned on the basis of SO{sub 4}{sup 2-}, CH{sub 3}NH{sub 3}{sup +}, and H{sub 2}O vibrations. The lifting of degeneracies of {nu}{sub 2}, {nu}{sub 3} and v{sub 4} modes and the appearance of {nu}{sub 1} and {nu}{sub 2} modes in the IR spectra confirm the lowering of symmetry of the SO{sub 4}{sup 2-} ion from T{sub d} to C{sub 1} in all of the title compounds. Bands obtained indicate that the distoration of the SO{sub 4}{sup 2-} ion in the four crystals are in the order, (CH{sub 3}NH{sub 3})Cu(SO{sub 4}){sub 2}{center_dot}6H{sub 2}O > (CH{sub 3}NH{sub 3}){sub 2}Ni(SO{sub 4}){sub 2}{center_dot}6H{sub 2}O > (CH{sub 3}NH{sub 3}){sub 2}Zn(SO{sub 4}){sub 2}{center_dot}6H{sub 2}O > Na{sub 2}Cu(SO{sub 4}){sub 2}{center_dot} 2H{sub 2}O. The appearance of NH{sub 3} stretching modes at wavenumbers lower than the values obtained for the free ion indicates the presence of hydrogen bonds between NH{sub 3} and SO{sub 4}{sup 2-} groups. The appearance of multiple bands in the blending and rocking mode regions and the broad nature of stretching modes show the existence of at least two symmetrically inequivalent water molecules in Na{sub 2}Cu(SO{sub 4}){sub 2}{center_dot}2H{sub 2}O. The shifting of stretching modes to lower wavenumbers and bending modes to higher wavenumbers of water molecules confirms the existence of strong hydrogen bonds in the crystal which is in agreement with the X-ray data. Bands indicate the presence of strong hydrogen bonds involving water molecules in (CH{sub 3}NH{sub 3}){sub 2}Cu(SO{sub 4}){sub 2}{center_dot}6H{sub 2}O and (CH{sub 3}NH{sub 3}){sub 2} Zn(SO{sub 4}){sub 2}{center_dot}6H{sub 2}O and of lesser strength in (CH{sub 3}NH{sub 3}){sub 2}Ni(SO{sub 4}){sub 2}{center_dot}6H{sub 2}O.

  2. Superconductivity in the presence of disorder in skutterudite-related La3Co4sub>Sn13 and La3Ru4sub>Sn13 compounds: Electrical transport and magnetic studies

    SciTech Connect

    Slebarski, A.; Maska, M. M.; Fijalkowski, M.; McElroy, C. A.; Maple, M. B.

    2015-06-25

    La3Co4sub>Sn13 and La3Ru4sub>Sn13 were categorized as BCS superconductors. In a plot of the critical field Hc2 vs T, La3Ru4sub>Sn13 displays a second superconducting phase at the higher critical temperature Tc*, characteristic of inhomogeneous superconductors, while La3Co4sub>Sn13 shows bulk superconductivity below Tc. We observe a decrease in critical temperatures with external pressure and magnetic field for both compounds. Additionally, for La3Ru4sub>Sn13 we find that Tc*/dP>dTc/dP. The pressure dependences of Tc are interpreted according to the McMillan theory and understood to be a consequence of lattice stiffening. The investigation of the superconducting state of La3CoxRu4–xSn13 shows a Tc* that is larger then Tc for x < 4. Furthermore, this unique and unexpected observation is discussed as a result of the local disorder and/or the effect of chemical pressure when Ru atoms are partially replaced by smaller Co atoms.

  3. Synthesis and X-ray structural investigation of K{sub 8}[(UO{sub 2}){sub 2}(C{sub 2}O{sub 4}){sub 2}(SeO{sub 4}){sub 4}] . 2H{sub 2}O

    SciTech Connect

    Serezhkina, L. B.; Peresypkina, E. V.; Virovets, A. V.; Verevkin, A. G.; Pushkin, D. V.

    2009-01-15

    Single crystals of the compound K{sub 8}[(UO{sub 2}){sub 2}(C{sub 2}O{sub 4}){sub 2}(SeO{sub 4})4] . 2H{sub 2}O (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 14.9290(4) A, b = 7.2800(2) A, c = 15.3165(4) A, {beta} = 109.188(1){sup o}, V = 1572.17(7) A{sup 3}, space group P2{sub 1}/n, Z = 2, and R = 0.0297. The uranium-containing structural units of crystals I are dimers of the composition [(UO {sub 2}){sub 2}(C{sub 2}O{sub 4}){sub 2}(SeO{sub 4}){sub 4}]{sup 8-}, which belong to the crystal-chemical group AB{sup 01}B{sup 2}M{sup 1} (A = UO{sub 2}{sup 2+}, B{sup 01} = C{sub 2}O{sub 4}{sup 2-}, B{sup 2} = SeO{sub 4}{sup 2-}, M{sup 1} = SeO{sub 4}{sup 2-}) of the uranyl complexes. The [(UO{sub 2}){sub 2}(C{sub 2}O{sub 4}){sub 2}(SeO{sub 4}){sub 4}]{sup 8-} dimers are joined into a three-dimensional framework through electrostatic interactions with the outer-sphere potassium cations.

  4. Study of phase relationships in the Sr{sub 3}(PO{sub 4}){sub 2}–CePO{sub 4} system. Phase diagram and thermal characteristics of phases

    SciTech Connect

    Matraszek, Aleksandra

    2013-07-15

    A diagram representing phase relationships in the Sr{sub 3}(PO{sub 4}){sub 2}–CePO{sub 4} phosphate system has been developed on the basis of results obtained by thermal analysis (DTA/DSC/TGA) and X-ray diffraction (XRD) methods. One intermediate compound with the formula Sr{sub 3}Ce(PO{sub 4}){sub 3} occurs in the Sr{sub 3}(PO{sub 4}){sub 2}–CePO{sub 4} system at temperatures exceeding 1045 °C. The compound has a eulytite structure with the following structural parameters: a=b=c=10.1655(8) Å, α=β=γ=90.00°, V=1050.46(6) Å{sup 3}. It's melting point exceeds 1950 °C. A limited solid solution exists in the system, which possesses the structure of a low-temperature form of Sr{sub 3}(PO{sub 4}){sub 2}. At 1000 °C the maximal concentration of CePO{sub 4} in the solid solution is below 20 mol%. The solid solution phase field narrows with increased temperature. There is a eutectic point in the (Sr{sub 3}(PO{sub 4}){sub 2}+Sr{sub 3}Ce(PO{sub 4}){sub 3}) phase field at 1765 °C and 15 mol% of CePO{sub 4}. The melting temperature of Sr{sub 3}(PO{sub 4}){sub 2} is 1882±15 °C. - Graphical abstract: The phase diagram of Sr{sub 3}(PO{sub 4}){sub 2}–CePO{sub 4} system showing the stability ranges of limited solid solution and Sr{sub 3}Ce(PO{sub 4}){sub 3} phases. - Highlights: • Sr{sub 3}(PO{sub 4}){sub 2} melts at 1882 °C. • Phase diagram of Sr{sub 3}(PO{sub 4}){sub 2}–CePO{sub 4} system has been proposed. • Limited solid solution of CePO{sub 4} in Sr{sub 3}(PO{sub 4}){sub 2} forms in the system. • The Sr{sub 3}Ce(PO{sub 4}){sub 2} phosphate is stable at temperatures above 1045 °C.

  5. Crystal structures of lazulite-type oxidephosphates Ti{sup III}Ti{sup IV}{sub 3}O{sub 3}(PO{sub 4}){sub 3} and M{sup III}{sub 4}Ti{sup IV}{sub 27}O{sub 24}(PO{sub 4}){sub 24} (M{sup III}=Ti, Cr, Fe)

    SciTech Connect

    Schoeneborn, M.; Glaum, R. Reinauer, F.

    2008-06-15

    Single crystals of the oxidephosphates Ti{sup III}Ti{sup IV}{sub 3}O{sub 3}(PO{sub 4}){sub 3} (black), Cr{sup III}{sub 4}Ti{sup IV}{sub 27}O{sub 24}(PO{sub 4}){sub 24} (red-brown, transparent), and Fe{sup III}{sub 4}Ti{sup IV}{sub 27}O{sub 24}(PO{sub 4}){sub 24} (brown) with edge-lengths up to 0.3 mm were grown by chemical vapour transport. The crystal structures of these orthorhombic members (space group F2dd ) of the lazulite/lipscombite structure family were refined from single-crystal data [Ti{sup III}Ti{sup IV}{sub 3}O{sub 3}(PO{sub 4}){sub 3}: Z=24, a=7.3261(9) A, b=22.166(5) A, c=39.239(8) A, R{sub 1}=0.029, wR{sub 2}=0.084, 6055 independent reflections, 301 variables; Cr{sup III}{sub 4}Ti{sup IV}{sub 27}O{sub 24}(PO{sub 4}){sub 24}: Z=1, a=7.419(3) A, b=21.640(5) A, c=13.057(4) A, R{sub 1}=0.037, wR{sub 2}=0.097, 1524 independent reflections, 111 variables; Fe{sup III}{sub 4}Ti{sup IV}{sub 27}O{sub 24}(PO{sub 4}){sub 24}: Z=1, a=7.4001(9) A, b=21.7503(2) A, c=12.775(3) A, R{sub 1}=0.049, wR{sub 2}=0.140, 1240 independent reflections, 112 variables). For Ti{sup III}Ti{sup IV}O{sub 3}(PO{sub 4}){sub 3} a well-ordered structure built from dimers [Ti{sup III,IV}{sub 2}O{sub 9}] and [Ti{sup IV,IV}{sub 2}O{sub 9}] and phosphate tetrahedra is found. The metal sites in the crystal structures of Cr{sub 4}Ti{sub 27}O{sub 24}(PO{sub 4}){sub 24} and Fe{sub 4}Ti{sub 27}O{sub 24}(PO{sub 4}){sub 24}, consisting of dimers [M{sup III}Ti{sup IV}O{sub 9}] and [Ti{sup IV,IV}{sub 2}O{sub 9}], monomeric [Ti{sup IV}O{sub 6}] octahedra, and phosphate tetrahedra, are heavily disordered. Site disorder, leading to partial occupancy of all octahedral voids of the parent lipscombite/lazulite structure, as well as splitting of the metal positions is observed. According to Guinier photographs Ti{sup III}{sub 4}Ti{sup IV}{sub 27}O{sub 24}(PO{sub 4}){sub 24} (a=7.418(2) A, b=21.933(6) A, c=12.948(7) A) is isotypic to the oxidephosphates M{sup III}{sub 4}Ti{sup IV}{sub 27}O{sub 24}(PO{sub 4

  6. Novel and De Novo Mutations Extend Association of POU3F4 with Distinct Clinical and Radiological Phenotype of Hearing Loss

    PubMed Central

    Pollak, Agnieszka; Lechowicz, Urszula; Kędra, Anna; Stawiński, Piotr; Rydzanicz, Małgorzata; Furmanek, Mariusz; Brzozowska, Małgorzata; Mrówka, Maciej; Skarżyński, Henryk; Skarżyński, Piotr H.

    2016-01-01

    POU3F4 mutations (DFNX2) are the most prevalent among non-syndromic X-linked hearing loss (HL) identified to date. Clinical manifestations of DFNX2 usually comprise congenital HL either sensorineural or mixed, a tendency towards perilymphatic gusher during otologic surgery and temporal bone malformations. The aim of the present study was to screen for POU3F4 mutations in a group of 30 subjects with a suggestive clinical phenotype as well as a group (N = 1671–2018) of unselected hearing loss patients. We also planned to analyze audiological and radiological features in patients with HL caused by POU3F4 defects. The molecular techniques used to detect POU3F4 mutations included whole exome sequencing (WES), Sanger sequencing and real-time polymerase chain reaction. Hearing status was assessed with pure-tone audiometry and auditory brainstem response. Computer tomography scans were evaluated to define the pattern of structural changes in the temporal bones. Six novel (p.Gln27*, p.Glu187*, p.Leu217*, p.Gln275*, p.Gln306*, p.Val324Asp) and two known (p.Ala116fs141*, p.Leu208*) POU3F4 mutations were detected in the studied cohort. All probands with POU3F4 defects suffered from bilateral, prelingual, severe to profound HL. Morphological changes of the temporal bone in these patients presented a similar pattern, including malformations of the internal auditory canal, vestibular aqueduct, modiolus and vestibule. Despite different localization in the POU3F4 gene all mutations severely impair the protein structure affecting at least one functional POU3F4 domain, and results in similar and severe clinical manifestations. Sequencing of the entire POU3F4 gene is recommended in patients with characteristic temporal bone malformations. Results of POU3F4 mutation testing are important not only for a proper genetic counseling, but also for adequate preparation and conduction of a surgical procedure. PMID:27941975

  7. Mixed tetrahedral anionic framework in the K{sub 3}Ga{sub 2}(PO{sub 4}){sub 3} crystal structure

    SciTech Connect

    Yakubovich, O. V.; Steele, I.; Kireev, V. V.

    2008-11-15

    The crystal structure of a new synthetic potassium gallophosphate K{sub 3}Ga{sub 2}(PO{sub 4}){sub 3} grown from a solution in the melt of a mixture of GaPO{sub 4} and K{sub 2}MoO{sub 4} is determined using X-ray diffraction (Bruker Smart diffractometer, 2{theta}{sub max}= 56.6{sup o}, R = 0.044 for 2931 reflections, T = 100 K). The main crystal data are as follows: a = 8.661(2) A, b = 17.002(4) A, c = 8.386(2) A, space group Pna2{sub 1}, Z= 4, and {rho}{sub calcd} = 2.91 g/cm{sup 3}. The synthesized crystals represent the third phase in the structure type previously established for the K{sub 3}Al{sub 2}[(As,P)O{sub 4}]{sub 3} compound. It is shown that the structure consists of a three-dimensional anionic microporous tetrahedral framework of the mixed type, which is formed by PO{sub 4} and GaO{sub 4} tetrahedra shared by vertices. Large-sized cations K{sup +} occupy channels of the zeolite-like framework. The crystal chemical features of the formation of structure types of compounds with mixed frameworks described by the general formula A{sub 3}{sup +}M{sub 2}{sup 3+}(TO{sub 4}){sub 3} (where A = K, Rb, (NH{sub 4}), Tl; M = Al, Ga, Fe, Sc, Yb; T = P, As) are analyzed.

  8. Competitive Reduction of Pertechnetate (99TcO4sub>- ) by Dissimilatory Metal Reducing Bacteria and Biogenic Fe(II)

    SciTech Connect

    Plymale, Andrew E.; Fredrickson, James K.; Zachara, John M.; Dohnalkova, Alice C.; Heald, Steve M.; Moore, Dean A.; Kennedy, David W.; Marshall, Matthew J.; Wang, Chongmin; Resch, Charles T.; Nachimuthu, Ponnusamy

    2011-01-06

    The fate of pertechnetate (99Tc(VII)O4sub>-) during bioreduction was investigated in the presence of 2-line ferrihydrite (Fh) and various dissimilatory metal reducing bacteria (DMRB) (Geobacter, Anaeromyxobacter, Shewanella) in comparison with TcO4sub>- bioreduction in the absence of Fh. In the presence of Fh, Tc was present primarily as a fine-grained Tc(IV)/Fe precipitate that was distinct from the Tc(IV)O2·nH2O solids produced by direct biological Tc(VII) reduction. Aqueous Tc concentrations (<0.2 μm) in the bioreduced Fh suspensions (1.7 to 3.2 × 10-9 mol L-1) were over 1 order of magnitude lower than when TcO4sub>- was biologically reduced in the absence of Fh (4.0 × 10-8 to 1.0 × 10-7 mol L-1). EXAFS analyses of the bioreduced Fh-Tc products were consistent with variable chain length Tc-O octahedra bonded to Fe-O octahedra associated with the surface of the residual or secondary Fe(III) oxide. In contrast, biogenic TcO2·nH2O had significantly more Tc-Tc second neighbors and a distinct long-range order consistent with small particle polymers of TcO2. In Fe-rich subsurface sediments, the reduction of Tc(VII) by Fe(II) may predominate over direct microbial pathways, potentially leading to lower concentrations of aqueous 99Tc(IV).

  9. Crystal structure, vibrational properties and luminescence of NaMg{sub 3}Al(MoO{sub 4}){sub 5} crystal doped with Cr{sup 3+} ions

    SciTech Connect

    Hermanowicz, K.; Maczka, M. . E-mail: m.maczka@int.pan.wroc.pl; Wolcyrz, M.; Tomaszewski, P.E.; Pasciak, M.; Hanuza, J.

    2006-03-15

    Crystals of NaMg{sub 3}Al(MoO{sub 4}){sub 5} doped with 0.5% Cr{sup 3+} ions have been synthesized and characterized by a single-crystal X-ray structure analysis and IR, Raman, electron absorption and luminescence spectroscopic studies. It has been shown that NaMg{sub 3}Al(MoO{sub 4}){sub 5} crystallizes in the P1-bar structure, with a=6.8744(8) A, b=6.9342(7) A, c=17.605(2) A, {alpha}=87.788(8){sup o}, {beta}=87.727(9){sup o}, {gamma}=78.501(9){sup o}, Z=2. The characteristic feature of the structure is its enormously large thermal displacement parameter for sodium, even at 105K. The IR and Raman spectra indicate significant interactions between the MoO{sub 4}{sup 2-} ions in the structure. The electron absorption, excitation and luminescence studies have shown that there are at least two different sites of incorporated Cr{sup 3+} ions in the NaMg{sub 3}Al(MoO{sub 4}){sub 5} crystal structure. They differ themselves by strength of crystalline field. One of them is characterized by Cr{sup 3+} in low ligand field and {sup 4}T{sub 2}->{sup 4}A{sub 2} emission whereas the second is characterized by higher strength of the crystal field and dominant {sup 2}E->{sup 4}A{sub 2} emission. Temperature-dependent studies show that the compound does not exhibit any phase transition.0.

  10. Writing of nonlinear optical Sm{sub 2}(MoO{sub 4}){sub 3} crystal lines at the surface of glass by samarium atom heat processing

    SciTech Connect

    Abe, M.; Benino, Y.; Fujiwara, T.; Komatsu, T.; Sato, R.

    2005-06-15

    Some glasses such as 21.25Sm{sub 2}O{sub 3}.63.75MoO{sub 3}.15B{sub 2}O{sub 3} (mol %) giving the formation of nonlinear optical Sm{sub 2}(MoO{sub 4}){sub 3} crystals through conventional crystallization in an electric furnace and through continuous-wave Nd: yttrium aluminum garnet (YAG) laser (wavelength: 1064 nm) irradiation (samarium atom heat processing) have been developed. It is proposed from x-ray diffraction analyses, micro-Raman-scattering spectra, and second-harmonic generation measurements that the crystal structure of Sm{sub 2}(MoO{sub 4}){sub 3} formed by the crystallization is the {beta}{sup '}-phase structure with an orthorhombic (noncentrosymmetric) symmetry. The lines consisting of nonlinear optical {beta}{sup '}-Sm{sub 2}(MoO{sub 4}){sub 3} crystals are written at the surface of glasses by YAG laser irradiation (laser power: P=0.4 W, laser scanning speed: S=1-10 {mu}m/s), and, in particular, homogeneous crystal lines are formed at the laser scanning speed of 1 {mu}m/s. Refractive index changes (not crystallization) are also induced by YAG laser irradiation of P=0.4 W and a high laser scanning speed of S=25 {mu}m/s. The crystallization mechanism in the laser-irradiated region has been proposed. The present study demonstrates that the samarium atom heat processing is a technique for the writing of rare earth containing optical nonlinear/ferroelectric crystal lines in glass.

  11. Oxidative Dehydrogenation of Cyclohexane on Cobalt Oxide (Co3O4sub>) Nanoparticles: The Effect of Particle Size on Activity and Selectivity

    SciTech Connect

    Tyo, Eric C.; Yin, Chunrong; Di Vece, Marcel; Qian, Qiang; Kwon, Gihan; Lee, Sungsik; Lee, Byeongdu; DeBartolo, Janae E.; Seifert, Sönke; Winans, Randall E.; Si, Rui; Ricks, Brian; Goergen, Simone; Rutter, Matthew; Zugic, Branko; Flytzani-Stephanopoulos, Maria; Wang, Zhi Wei; Palmer, Richard E.; Neurock, Matthew; Vajda, Stefan

    2012-10-02

    The oxidative dehydrogenation of cyclohexane by cobalt oxide nanoparticles was studied via temperature programmed reaction combined with in situ grazing incidence X-ray absorption spectroscopy and grazing incidence small-angle X-ray scattering and theoretical calculations on model Co3O4sub> substrates. Both 6 and 12 nm Co3O4sub> nanoparticles were made through a surfactant-free preparation and dispersed on an Al2O3 surface formed by atomic layer deposition. Under reaction conditions the nanoparticles retained their oxidation state and did not sinter. They instead underwent an assembly/disassembly process and could reorganize within their assemblies. The selectivity of the catalyst was found to be size- and temperature-dependent, with larger particles preferentially producing cyclohexene at lower temperatures and smaller particles predominantly resulting in benzene at higher temperatures. The mechanistic features thought to control the oxidative dehydrogenation of cyclohexane and other light alkanes on cobalt oxide were established by carrying out density functional theory calculations on the activation of propane, a surrogate model alkane, over model Co3O4sub> surfaces. The initial activation of the alkane (propane) proceeds via hydrogen abstraction over surface oxygen sites. The subsequent activation of the resulting alkoxide intermediate occurs at a second surface oxygen site to form the alkene (propene) which then desorbs from the surface. Hydroxyl recombination results in the formation of water which desorbs from the surface. Finally, oxygen is necessary to regenerate the surface oxygen sites, catalyze C–H activation steps, and minimize catalyst degradation.

  12. Dynamic Oxygen on Surface: Catalytic Intermediate and Coking Barrier in the Modeled CO2 Reforming of CH4sub> on Ni (111)

    SciTech Connect

    Yuan, Kaidi; Zhong, Jian-Qiang; Zhou, Xiong; Xu, Leilei; Bergman, Susanna L.; Wu, Kai; Xu, Guo Qin; Bernasek, Steven L.; Li, He Xing; Chen, Wei

    2016-06-08

    We identify Ni-O phases as important intermediates in a model dry (CO2) reforming of methane catalyzed by Ni (111), based on results from in operando near ambient X-ray photoelectron spectroscopy (NAP-XPS), low energy electron diffraction (LEED) and scanning tunneling microscopy (STM). We find that under a CO2 or CO2-CH4sub> atmosphere, the Ni-O phases exist as p(2×2) structured chemisorbed oxygen (Chem-O), epitaxial NiO (111), or oxygen-rich NixOy (x2O3), depending on the chemical potential. The growth rates of the Ni-O phases have a negative correlation with temperature from 600 K to 900 K, proving that their dynamic concentrations in the reaction are not limited by CO2 activation, but by their thermal stability. Between 300 K and 800 K (1:1 CH4sub> and CO2 mixture), oxidation by CO2is dominant, resulting in a fully Ni-O covered surface. Between 800 K and 900 K, a partially oxidized Ni (111) exists which could greatly facilitate the effective conversion of CH4sub>. As CH4sub> is activation-limited and dissociates mainly on metallic nickel, the released carbon species can quickly react with the adjacent oxygen (Ni-O phases) to form CO. After combining with carbon and releasing CO molecules, the Ni-O phases can be further regenerated through oxidation by CO2. In this way, the Ni-O phases participate in the catalytic process, acting as an intermediate in addition to the previously reported Ni-C phases. We also reveal the carbon phobic property of the Ni-O phases, which links to the intrinsic coking resistance of the catalysts. The low dynamic coverage of surface oxygen at higher temperatures (>900 K) is inferred to be an underlying factor causing carbon aggregation. Therefore solutions based on Ni-O stabilization are proposed in developing coking resisting catalysts.

  13. High power TEM00 picosecond output based on a Nd:GdVO4sub> discrete path Innoslab amplifier.

    PubMed

    Guo, Jie; Lin, Hua; Li, Jinfeng; Gao, Peng; Liang, Xiaoyan

    2016-06-15

    We propose a technique for eliminating self-lasing and suppressing amplified spontaneous emission in a partially pumped slab amplifier with a discrete path configuration. High gain character and homogeneous gain distribution were well preserved with the proposed scheme. Based on the Nd:GdVO4sub> crystal, a 99 W, 12.4 ps TEM00 laser output was achieved with a 42% extraction efficiency. The diffraction limited beam quality remained undisturbed after amplification with Mx2=1.09 and My2=1.07 in the orthogonal directions.

  14. Global maxima for the acousto-optic effect in SrB4sub>O7 crystals.

    PubMed

    Oleh, Buryy; Nazariy, Andrushchak; Andriy, Ratych; Natalia, Demyanyshyn; Bohdan, Mytsyk; Anatoliy, Andrushchak

    2017-03-01

    For the first time, the global maxima of the acousto-optic interaction are theoretically determined for biaxial SrB4sub>O7 crystals by the extreme surfaces method. As it is shown, the highest value of the acousto-optic figure-of-merit M2 is equal to 6.3×10-16  s3/kg and achieved in the case of the isotropic diffraction of the electromagnetic wave propagating in the [010] direction on the fast quasi-transversal acoustic wave.

  15. Improved synthesis and crystal structure of the flexible pillared layer porous coordination polymer: Ni(1,2-bis(4-pyridyl)ethylene)[Ni(CN)4sub>

    SciTech Connect

    Wong-Ng, W.; Culp, J. T.; Chen, Y. S.; Zavalij, P.; Espinal, L.; Siderius, D. W.; Allen, A. J.; Scheins, S.; Matranga, C.

    2013-01-01

    This paper reports our synthesis of flexible coordination polymer, Ni(L)[Ni(CN)4sub>], (L = 1,2-bis(4-pyridyl)ethylene (nicknamed bpene)), and its structural characterization using synchrotron single crystal X-ray diffraction. The structure of the purplish crystals has been determined to be monoclinic, space group P21/m, a = 13.5941(12) Å, b = 14.3621(12) Å, c = 14.2561(12) Å, β = 96.141(2)°, V = 2767.4(4) Å3, Z = 4, Dc = 1.46 g cm-1. Ni(bpene)[Ni(CN)4sub>] assumes a pillared layer structure with layers defined by Ni[Ni(CN)4sub>]n nets and bpene ligands acting as pillars. With the present crystallization technique which involves the use of concentrated ammonium hydroxide solution and dimethyl sulfoxide (DMSO), disordered free bpene ligands and solvents of crystallization (DMSO and water molecules) occupy the pores, resulting in a formula of Ni(bpene)[Ni(CN)4sub>](1/2)bpene∙DMSO2H2O, or Ni2N7C24H25SO3. Without the inclusion of free bpene ligands and solvent molecules, the free volume is approximately 61% of the total volume; this free volume fraction is reduced to 50% with the free ligands present. Pores without the free ligands were found to have a local diameter of 5.7 Å and a main aperture of 3.5 Å. Based on the successful crystal synthesis, we also devised a new bulk synthetic technique which yielded a polycrystalline material with a significantly improved CO2 uptake as compared to the originally reported powder material. The improved synthetic technique yielded a polycrystalline material with 40% higher CO2 uptake compared to the previously reported powder material. An estimated 14.4 molecules of CO2 per unit cell was obtained.

  16. New phases in the system LiMnVO{sub 4}-Mn{sub 3}(VO{sub 4}){sub 2}

    SciTech Connect

    Clemens, Oliver; Haberkorn, Robert; Beck, Horst Philipp

    2011-10-15

    The synthesis of orthorhombic Mn{sub 3}(VO{sub 4}){sub 2} via a simple solid state route as well as the description of a new tetragonal high temperature phase are reported in this paper. Additionally, the system LiMnVO{sub 4}-Mn{sub 3}(VO{sub 4}){sub 2} (=Mn{sub 1.5}VO{sub 4}), described by the formula Li{sub x}Mn{sub 1.5-x/2}VO{sub 4}, is investigated in detail, showing that substitution of one Mn{sup 2+} in Mn{sub 1.5}VO{sub 4} by two Li{sup +} ions favors the formation of the tetragonal high temperature phase for x{<=}0.22. This substitution is facilitated by the statistical half occupancy of the 4b site by Mn{sup 2+} in tetragonal Mn{sub 1.5}VO{sub 4}, whereas additional crystallographic sites would have to be occupied in the orthorhombic phase. The inverse substitution of Li by Mn in orthorhombic LiMnVO{sub 4} is also shown to be possible in the range 0.72{<=}x{<=}1. For 0.22{<=}x{<=}0.72, there is a large miscibility gap with a two phase mixture of the tetragonal Mn{sub 1.5}VO{sub 4} type and orthorhombic LiMnVO{sub 4} type phases. - Graphical Abstract: The unusual coordination of Mn in the form of a stella quadrangula with the surrounding vanadate groups. Highlights: > First synthesis of orthorhombic Mn{sub 3}(VO{sub 4}){sub 2} via a simple solid state route. > The crystal chemistry of the phases involved is rather complicated and it depends on the amount of Li that is incorporated. > System LiMnVO{sub 4}-Mn{sub 3}(VO{sub 4}){sub 2} (=Mn{sub 1.5}VO{sub 4}), described by the formula Li{sub x}Mn{sub 1.5-x/2}VO{sub 4}, is investigated in detail.

  17. Widely tunable in the mid-IR BaGa4sub>Se7 optical parametric oscillator pumped at 1064  nm.

    PubMed

    Kostyukova, Nadezhda Y; Boyko, Andrey A; Badikov, Valeriy; Badikov, Dmitrii; Shevyrdyaeva, Galina; Panyutin, Vladimir; Marchev, Georgi M; Kolker, Dmitry B; Petrov, Valentin

    2016-08-01

    A BaGa4sub>Se7 nanosecond optical parametric oscillator (OPO) shows extremely wide idler tunability in the mid-IR (2.7-17 μm) under 1.064 μm pumping. The ∼10  ns pulses at ∼7.2  μm have an energy of 3.7 mJ at 10 Hz. The pump-to-idler conversion efficiency for this wavelength reaches 5.9% with a slope of 6.5% corresponding to a quantum conversion efficiency or pump depletion of 40%.

  18. Unique edge-sharing sulfate-transition metal coordination in Na{sub 2}M(SO{sub 4}){sub 2} (M=Ni and Co)

    SciTech Connect

    Fry, Allyson M.; Sweeney, Owen T.; Adam Phelan, W.; Drichko, Natalia; Siegler, Maxime A.; McQueen, Tyrel M.

    2015-02-15

    Two compounds, Na{sub 2}Ni(SO{sub 4}){sub 2} and Na{sub 2}Co(SO{sub 4}){sub 2}, were synthesized and their structure and properties were characterized. They adopt a structure that contains a bidentate coordination of sulfate to the transition metal center, which was determined via single crystal X-ray diffraction combined with model refinements to both laboratory X-ray and time-of-flight neutron powder diffraction data. The compounds were both found to crystallize in the C2/c space group with Z=24 and a unit cell of a=23.3461(3) Å, b=10.3004(1) Å, c=17.4115(2) Å, β=98.8659(9)°, and V=4136.99(8) Å{sup 3} for the cobalt analog and a=23.2253(1) Å, b=10.26155(6) Å, c=17.3353(1) Å, β=99.0376(5)°, and V=4080.20(5) Å{sup 3} for the nickel analog. Magnetization measurements show that the transition metal centers have negligible interactions with neighboring sites. Infrared and Raman spectroscopies were used to further probe the unique sulfate-transition metal coordination, and confirm the bidentate binding motif. The resulting pseudo-trigonal bipyramidal coordination produces vivid violet, Na{sub 2}Co(SO{sub 4}){sub 2}, and yellow, Na{sub 2}Ni(SO{sub 4}){sub 2}, colors that were probed by diffuse reflectance. - Graphical abstract: Two blue distorted transition metal octahedra (oxygen in red) bridged by two sulfate tetrahedra are shown here. Each bridging sulfate tetrahedra shares an edge with one octahedron and a corner with the other. All of the remaining corners of the octahedra are corner sharing with four tetrahedra forming a polyhedral network. - Highlights: • Structure of Na2Ni(SO4)2 and Na2Co(SO4)2 is determined. • Unique sulfate-transition metal binding observed in the new structure. • Combined diffraction and spectroscopic techniques were used. • Magnetization measurements show negligible interactions between sites.

  19. Ultrafast dynamics of localized magnetic moments in the unconventional Mott insulator Sr2IrO4sub>

    SciTech Connect

    Krupin, O.; Dakovski, G. L.; Kim, B. J.; Kim, J. W.; Kim, Jungho; Mishra, S.; Chuang, Yi -De; Serrao, C. R.; Lee, W. -S.; Schlotter, W. F.; Minitti, M. P.; Zhu, D.; Fritz, D.; Chollet, M.; Ramesh, R.; Molodtsov, S. L.; Turner, J. J.

    2016-06-16

    Here, we report a time-resolved study of the ultrafast dynamics of the magnetic moments formed by the ${{J}_{\\text{eff}}}=1/2$ states in Sr2IrO4sub> by directly probing the localized iridium 5d magnetic state through resonant x-ray diffraction. Using optical pump–hard x-ray probe measurements, two relaxation time scales were determined: a fast fluence-independent relaxation is found to take place on a time scale of 1.5 ps, followed by a slower relaxation on a time scale of 500 ps–1.5 ns.

  20. Structure of Cs{sub 4}(HSO{sub 4}){sub 3}(H{sub 2}PO{sub 4}) single crystals

    SciTech Connect

    Makarova, I. P. Grebenev, V. V.; Vasil’ev, I. I.; Dmitricheva, E. V.; Komornikov, V. A.; Dolbinina, V. V.; Mikheikin, A. S.

    2016-01-15

    Single crystals of Cs{sub 4}(HSO{sub 4}){sub 3}(H{sub 2}PO{sub 4}) are synthesized and studied for the first time. The new compound is found in the course of studies of the phase diagram of the CsHSO{sub 4}–CsH{sub 2}PO{sub 4}–H{sub 2}O triple system. Data on the atomic crystal structure of single-crystalline and powder specimens, as well as on structural phase transitions, are obtained.

  1. Investigation of the structure of Cs{sub 3}(HSO{sub 4}){sub 2}(H{sub 2}PO{sub 4}) single crystals

    SciTech Connect

    Makarova, I. P. Grebenev, V. V.; Vasiliev, I. I.; Dmitricheva, E. V.; Komornikov, V. A.; Dolbinina, V. V.

    2015-07-15

    Cs{sub 3}(HSO{sub 4}){sub 2}(H{sub 2}PO{sub 4}) single crystals, obtained for the first time based on a systematic study of the phase diagram of the CsH{sub 2}PO{sub 4}–CsHSO{sub 4}–H{sub 2}O ternary system, have been studied by X-ray diffraction. The atomic structure of the crystals at room temperature is determined, and their structural features are analyzed.

  2. Injectable Silica–Permanganate Gel as a Slow-Release MnO4sub>- Source for Groundwater Remediation. Rheological Properties and Release Dynamics

    SciTech Connect

    Yang, Shuo; Oostrom, Martinus; Truex, Michael J.; Li, G.; Zhong, Lirong

    2016-01-12

    Injectable slow-release permanganate gel (ISRPG), formed by mixing KMnO4sub> solution with fumed silica powder, may have a potential application in remediating chlorinated solvent plumes in groundwater. A series of batch, column, and flow cell experiments has been completed to test the gel behavior under a variety of conditions. The experiments have provided information on ISRPG rheology, permanganate (MnO4sub>- ) release dynamics and distribution, and trichloroethene (TCE) degradation by ISRPG-released oxidant. The gel possesses remarkable shear thinning characteristics, resulting in a relative low viscosity during mixing, and facilitating its subsurface injection and distribution. Batch tests revealed that MnO4sub>- was diffused out from ISRPG into water while the gel did not dissolve or disperse into water but maintained its initial shape. Column experiments showed that MnO4sub>- release from ISRPG lasted considerably longer than the release from aqueous solution. TCE degradation by ISRPG-released MnO4sub>- was much more effective than that when MnO4sub>- was delivered using aqueous solution injection. In two-dimensional flow cell experiments, it was demonstrated that ISRPG slowly released a long-lasting low concentration MnO4sub>- plume sufficient for remediation and sustainable in an aquifer for a long period of time.

  3. Toxicity and carcinogenicity studies of Caramel Colour IV in F344 rats and B6C3F1 mice.

    PubMed

    MacKenzie, K M; Boysen, B G; Field, W E; Petsel, S R; Chappel, C I; Emerson, J L; Stanley, J

    1992-05-01

    Caramel Colour IV, a type of caramel colour used in the manufacture of cola soft drinks, was evaluated for subchronic and chronic toxicity in rats, and carcinogenicity in Fischer-344 (F344) rats and B6C3F1 mice. In each of the studies, Caramel Colour IV was mixed with demineralized water and the solutions given to the animals ad lib. in the drinking fluid. The concentrations of Caramel Colour IV in the drinking fluid were adjusted periodically to achieve the desired caramel colour intake per kg body weight. In the range-finding studies, groups of 30 rats/sex were given Caramel Colour IV at levels of 0, 15, 20, 25 or 30 g/kg for 13 wk, and groups of 10 male rats were given levels of 0, 2.5, 5, 10 or 15 g/kg for 6 wk followed, for some dose groups, by a 2-wk withdrawal period, and then re-initiation of dosing for another 2 wk. In the rat chronic toxicity study, levels of Caramel Colour IV of 0, 2.5, 5, 7.5 or 10 g/kg were given to groups of 25 rats/sex for 12 months. The test groups in the rat and mouse carcinogenicity studies were composed of 50 animals/sex and each species was given the caramel colour at levels of 0, 0, 2.5, 5 or 10 g/kg for 24 months. In each of the studies, treated animals tended to have dose-related lower water consumption than controls. This was attributed to poor palatability of the drinking fluid, and was generally associated with decreased food consumption and body weights. Rats given caramel colour often had soft or liquid malodorous faeces although there were no treatment-related ante-mortem observations in mice. Blood biochemical changes in the rat (i.e. reduced blood urea nitrogen, alkaline phosphatase and total serum protein) appeared to be related to dietary influences and were not considered toxicologically significant. There were no treatment-related alterations in haematological variables or treatment-related differences in survival or in the incidence of benign or malignant tumours among treated and control groups and no

  4. Investigations of the R5(SixGe1-x)4sub> Intermetallic Compounds by X-Ray Resonant Magnetic Scattering

    SciTech Connect

    Tan, Lizhi

    2008-08-18

    The XRMS experiment on the Gd5Ge4sub> system has shown that, below the Neel temperature, TN = 127 K, the magnetic unit cells is the same as the chemical unit cell. From azimuth scans and the Q dependence of the magnetic scattering, all three Gd sites in the structure were determined to be in the same magnetic space group Pnma. The magnetic moments are aligned along the c-axis and the c-components of the magnetic moments at the three different sites are equal. The ferromagnetic slabs are stacked antiferromagnetically along the b-direction. They found an unusual order parameter curve in Gd5Ge4sub>. A spin-reorientation transition is a possibility in Gd5Ge4sub>, which is similar to the Tb5Ge4sub> case. Tb5Ge4sub> possesses the same Sm5Ge4sub>-type crystallographic structure and the same magnetic space group as Gd5Ge4sub> does. The difference in magnetic structure is that Tb5Ge4sub> has a canted one but Gd5Ge4sub> has nearly a collinear one in the low temperature antiferromagnetic phase. The competition between the magneto-crystalline anisotropy and the nearest-neighbor magnetic exchange interactions may allow a 3-dimensional canted antiferromagnetic structure in Tb5Ge4sub>. The spin-reorientation transition in both Gd5Ge4sub> and Tb5Ge4sub> may arise from the competition between the magnetic anisotropy from the spin-orbit coupling of the conduction electrons and the dipolar interactions anisotropy.

  5. Luminescent properties of SrZn{sub 2}(PO{sub 4}){sub 2}:Tb{sup 3+} and its luminescence improvement by incorporating A{sup +} (A=Li, Na, and K)

    SciTech Connect

    Li, Panlai Wang, Zhijun Yang, Zhiping; Guo, Qinglin

    2014-12-15

    A novel green phosphor SrZn{sub 2}(PO{sub 4}){sub 2}:Tb{sup 3+} is synthesized by a high temperature solid-state method, and its luminescent property is investigated. X-ray diffraction patterns of SrZn{sub 2}(PO{sub 4}){sub 2}:Tb{sup 3+} indicate a similarity crystalline phase to SrZn{sub 2}(PO{sub 4}){sub 2}. SrZn{sub 2}(PO{sub 4}){sub 2}:Tb{sup 3+} shows green emission under 369 nm excitation, and the prominent luminescence in green (544 nm) due to {sup 5}D{sub 4}–{sup 7}F{sub 5} transition of Tb{sup 3+}. For the 544 nm emission, excitation spectrum has several excitation band from 200 nm to 400 nm. Emission intensity of SrZn{sub 2}(PO{sub 4}){sub 2}:Tb{sup 3+} is influenced by Tb{sup 3+} concentration, and concentration quenching effect of Tb{sup 3+} in SrZn{sub 2}(PO{sub 4}){sub 2} is also observed. With incorporating A{sup +} (A=Li, Na, and K) as compensator charge, the emission intensity of SrZn{sub 2}(PO{sub 4}){sub 2}:Tb{sup 3+} can be obviously enhanced. CIE color coordinates of SrZn{sub 2}(PO{sub 4}){sub 2}:Tb{sup 3+} locate in the green region. The results indicate this phosphor may be a potential application in white LEDs. - Graphical abstract: SrZn{sub 2}(PO{sub 4}){sub 2}:Tb{sup 3+} can produce green emission under near-UV excitation, and its luminescent properties can be improved by incorporating A{sup +} (A=Li, Na, and K). - Highlights: • SrZn{sub 2}(PO{sub 4}){sub 2}:Tb{sup 3+} can produce green emission under near-UV excitation. • Concentration quenching effect of Tb{sup 3+} in SrZn{sub 2}(PO{sub 4}){sub 2} is observed. • Emission intensities of SrZn{sub 2}(PO{sub 4}){sub 2}:Tb{sup 3+} are enhanced by codoped A{sup +} (A=Li, Na, K)

  6. Nasal dosimetry of inspired naphthalene vapor in the male and female B6C3F1 mouse.

    PubMed

    Morris, John B

    2013-07-05

    Naphthalene vapor is a nasal cytotoxicant in the rat and mouse but is a nasal carcinogen in only the rat. Inhalation dosimetry is a critical aspect of the inhalation toxicology of inspired vapors and may contribute to the species differences in the nasal response. To define the nasal dosimetry of naphthalene in the B6C3F1 male and female mouse, uptake of naphthalene vapor was measured in the surgically isolated upper respiratory tract (URT) at inspiratory flow rates of 25 or 50 ml/min. Uptake was measured at multiple concentrations (0.5, 3, 10, 30 ppm) in controls and mice treated with the cytochrome P450 inhibitor 5-phenyl-1-pentyne. In both sexes, URT uptake efficiency was strongly concentration dependent averaging 90% at 0.5 ppm compared to 50% at 30 ppm (25 ml/min flow rate), indicating saturable processes were involved. Both uptake efficiency and the concentration dependence of uptake were significantly diminished by 5-phenyl-1-pentyne indicating inspired naphthalene vapor is extensively metabolized in the mouse nose with saturation of metabolism occurring at the higher concentrations. A hybrid computational fluid dynamic physiologically based pharmacokinetic model was developed for nasal dosimetry. This model accurately predicted the observed URT uptake efficiencies. Overall, the high URT uptake efficiency of naphthalene in the mouse nose indicates the absence of a tumorigenic response is not attributable to low delivered dose rates in this species.

  7. Multiple-site carcinogenicity of benzene in fischer 344 rats and B6C3F1 mice

    SciTech Connect

    Huff, J.E.; Haseman, J.K.; DeMarini, D.M.; Eustis, S.; Maronpot, R.R.

    1989-01-01

    Two-year toxicology and carcinogenesis studies of benzene were conducted in groups of 50 F344/N rats and 50 B6C3F1 mice of each sex and for each of three exposure doses and vehicle controls. These studies were conducted because of large production volume and widespread human exposure to benzene, because of the epidemiologic association with leukemia, and because previous studies were considered inadequate for determining carcinogenicity. Doses of 0, 50, 100 or 200 mg/kg body weight benzene in corn oil (5 ml/kg) were administered by gavage to male rats, 5 days per week for 103 weeks. Doses of 0, 25, 50, or 100 mg/kg benzene in corn oil were administered by gavage to female rats and to male and female mice for 103 weeks. At week 92 for rats and week 91 for mice, survival was greater than 60% in all groups; most of the animals that died before week 103 had neoplasia. Benzene-associated nonneoplastic or neoplastic effects on the hematopoietic system, Zymbal gland, forestomach, and adrenal gland were found for rats and mice.

  8. Absorption and metabolism of triclosan after application to the skin of B6C3F1 mice.

    PubMed

    Fang, Jia-Long; Vanlandingham, Michelle; da Costa, Gonçalo Gamboa; Beland, Frederick A

    2016-05-01

    Triclosan is used as an antimicrobial agent in personal care products, household items, medical devices, and clinical settings. Humans can receive lifelong exposures to triclosan; however, data on the toxicity and carcinogenicity after topical application are lacking. This study determined the absorption, distribution, metabolism, and excretion of triclosan after application to the skin of B6C3F1 mice. [(14)C(U)]triclosan (10 or 100 mg triclosan/kg body weight) was administered topically to mice in two separate experiments: a vehicle selection experiment using propylene glycol, ethanol, and a generic cosmetic cream, and a toxicokinetic experiment. Mice were killed up to 72 h after triclosan administration, and excreta and tissues were analyzed for radioactivity. Ethanol had the best properties of the vehicles evaluated. Maximum absorption was obtained at approximately 12 h after dosing. Radioactivity appeared in the excreta and in all tissues examined, with the highest levels in the gall bladder and the lowest levels in the brain. Triclosan was metabolized to triclosan sulfate, triclosan glucuronide, 2,4-dichlorophenol, and hydroxytriclosan. The metabolite profile was tissue-dependent and the predominant route of excretion was fecal. The AUC(0-∞) and the Cmax of plasma and liver in females were greater than those in males. Slightly lower absorption was observed in mice with Elizabethan collars.

  9. Expression by midbrain dopamine neurons of Sema3A and 3F receptors is associated with chemorepulsion in vitro but a mild in vivo phenotype.

    PubMed

    Torre, Enrique R; Gutekunst, Claire-Anne; Gross, Robert E

    2010-06-01

    Here we explore the role of semaphorin 3A and 3F (Sema3A, Sema3F) in the formation of the mesotelencephalic pathway. We show that Sema3A and 3F are expressed in the ventral mesencephalon (VM) of E13.5 rat embryos; the receptors Neuropilin 1 and Neuropilin 2, and co-receptors L1CAM, NrCAM, and Plexins A1 and A3 but not A4 are expressed by VM dopaminergic neurons; these neurons bind Sema3A and 3F in vitro which induces collapse of their growth cones and elicits, with different potencies, a repulsive response; and this response is absent in axons from Nrp1 and Nrp2 null embryos. Despite these in vitro effects, only very mild anatomical defects were detected in the organization of the mesotelencephalic pathway in embryonic and adult Nrp1 or Nrp2 null mice. However, the dopaminergic meso-habenular pathway and catecholaminergic neurons in the parafascicular and paraventricular nuclei of the thalamus were significantly affected in Nrp2 null mice. These data are consistent with a model whereby Sema3A and 3F, in combination with other guidance molecules, contributes to the navigation of DA axons to their final synaptic targets.

  10. Results of surgical treatment of retinal detachments complicated with proliferative vitreoretinopathies with the use of perfluropropane (C3F8) gas.

    PubMed

    Vardanyan, A H; Hovakimyan, A V; Hambartsumyan, A V

    2000-01-01

    The aim of the current study is the efficiency assessment of C3F8 gas usage in posterior vitrectomies in patients having retinal detachment of different etiologies with presence of proliferative vitreoretinopathies and retinal tears. 34 patients have undergone posterior vitrectomy with the usage of perfluoropropane C3F8 gas for providing internal tamponade. Total attachment of retina has been attached in all 34 cases and C3F8 gas has been injected in each eye. The most frequent complications that have been revealed after the usage of C3F8 gas and their management are reflected in the article. Thus, we came to a conclusion that vitrectomy in combination with episcleral buckling, transvitreal drainage of subretinal liquid, diode endolaser coagulation of retina and internal tamponade with C3F8 gas is effective and pathogenetikally proved method for treatment of rhegmatogenous retinal detachments complicated with severe vitreoretinopathies. The achievement of perfect anatomical results depends on manifestation degree of proliferative vitreoretinopathy. This study was supported by grant of the Ministry of Health of Armenia.

  11. Synthesis and structure of a new layered oxyfluoride Sr{sub 2}ScO{sub 3}F with photocatalytic property

    SciTech Connect

    Wang, Yongkun; Tang, Kaibin Zhu, Baichuan; Wang, Dake; Hao, Qiaoyan; Wang, Yan

    2015-05-15

    Highlights: • A new oxyfluoride compound Sr{sub 2}ScO{sub 3}F was prepared by a solid state route. • The structure of this compound was determined by GSAS program based on XRD data. • The photocatalytic property was investigated under UV irradiation. - Abstract: A new Ruddlesden–Popper type scandium oxyfluoride, Sr{sub 2}ScO{sub 3}F, was synthesized by a conventional solid state reaction route. The detailed structure of Sr{sub 2}ScO{sub 3}F was investigated using X-ray diffraction (XRD) and selected area electron diffraction (SAED). The disorder distribution pattern of fluorine anions was determined by the {sup 19}F nuclear magnetic resonance (NMR) spectrum. The compound crystallizes in a K{sub 2}NiF{sub 4}-type tetragonal structure (space group I4/mmm) with O/F anions disordered over the apical sites of the perovskite-type Sc(O,F){sub 6} octahedron layers interleaved with strontium cations. Ultraviolet–visible (UV–vis) diffuse reflection spectrum of the prepared Sr{sub 2}ScO{sub 3}F indicates that it has an absorption in the UV–vis region. The photocatalytic activity of Sr{sub 2}ScO{sub 3}F was further investigated, showing an effective photodegradation of Rhodamine-B (RB) within 2 h under UV light irradiation.

  12. Metastability in the MgAl2O4sub>-Al2O3 System

    SciTech Connect

    Wilkerson, Kelley R.; Smith, Jeffrey D.; Hemrick, James G.

    2014-07-22

    Aluminum oxide must take a spinel form ( γ-Al2O3) at elevated temperatures in order for extensive solid solution to form between MgAl2O4sub> and α-Al2O3. The solvus line between MgAl2O4sub> and Al2O3 has been defined at 79.6 wt% Al2O3 at 1500°C, 83.0 wt% Al2O3 at 1600°C, and 86.5 wt% Al2O3 at 1700°C. A metastable region has been defined at temperatures up to 1700°C which could have significant implications for material processing and properties. Additionally, initial processing could have major implications on final chemistry. The spinel solid solution region has been extended to form an infinite solid solution with Al2O3 at elevated temperatures. A minimum in melting at 1975°C and a chemistry of 96 wt% Al2O3 rather than a eutectic is present, resulting in no eutectic crystal formation during solidification.

  13. Thermodynamic Properties of α-Fe2O3 and Fe3O4sub> Nanoparticles

    SciTech Connect

    Spencer, Elinor C.; Ross, Nancy L.; Olsen, Rebecca E.; Huang, Baiyu; Kolesnikov, Alexander I.; Woodfield, Brian F.

    2015-04-21

    Here we comprehansively assessed the thermodynamic properties of hydrated α-Fe2O3 (hematite) and Fe3O4sub> (magnetite) nanoparticles. In addition to 9 nm Fe3O4sub>, three α-e2O3nanoparticles samples of different sizes (11, 14, and 25 nm) and bulk α-e2O3 have been evaluated by inelastic neutron scattering methods. The contribution of the two-level magnetic spin flip transition to the heat capacity of the α-e2O3 particles has been determined. The isochoric heat capacity of the water confined on the surface of these two types of iron oxide particles have been calculated from their INS spectra, and is affected by the chemical composition of the underlying particle. Furthermore, the heat capacity and dynamics of the particle hydration layers appear to be influenced by a complex array of factors including particle size, water coverage, and possibly the magnetic state of the particle itself.

  14. Structural instability of the CoO4sub> tetrahedral chain in SrCoO3-δ thin films

    SciTech Connect

    Glamazda, A.; Choi, Kwang-yong; Lemmens, P.; Choi, Woo Seok; Jeen, Hyoungjeen; Meyer, Tricia L.; Lee, Ho Nyung

    2015-08-31

    Raman scattering experiments together with detailed lattice dynamic calculations are performed to elucidate crystallographic and electronic peculiarities of SrCoO3-δ films. We observe that the 85 cm-1 phonon mode involving the rotation of a CoO4sub> tetrahedron undergoes a hardening by 21 cm-1 when the temperature is decreased. In addition, new phonon modes appear at 651.5 and 697.6 cm-1 . The latter modes are attributed to the Jahn-Teller activated modes. Upon cooling from room temperature, all phonons exhibit an exponential-like increase of intensity with a characteristic energy of about 103–107 K. We attribute this phenomenon to an instability of the CoO4sub> tetrahedral chain structure, which constitutes a key ingredient to understand the electronic and structural properties of the brownmillerite SrCoO2.5.

  15. Monodispersed Li4sub>Ti5O12 with Controlled Morphology as High Power Lithium Ion Battery Anodes

    SciTech Connect

    Li, Yunchao; Fu, Guoyi; Watson, Mark; Harrison, Stephen; Paranthaman, M. Parans

    2016-05-31

    Monodispersed Li4sub>Ti5O12 (LTO) nanoparticles with controlled microstructure were successfully synthesized by a combination of hydrolysis and hydrothermal method followed by a post-annealing process. The scanning electron microscopy images showed that particles with a size of 30-40 nm were precisely controlled throughout the synthesis process. The electrochemical tests of the as-prepared LTO electrodes in a half-cell proved its high rate performance and outstanding cyclability which benefits from the preserved well-controlled nanoparticle size and morphology. LTO electrodes were also tested in a full cell configuration in pairing with LiFePO4sub> cathodes, which demonstrated a capacity of 147.3 mAh g-1. In addition, we have also demonstrated that LTO materials prepared using lithium salts separated from geothermal brine solutions had good cyclability. These demonstrations provide a promising way for making low-cost, large-scale LTO electrode materials for energy storage applications.

  16. Effect of Yb doping on the refractive index and thermo-optic coefficient of YVO4sub> single crystals.

    PubMed

    Soharab, M; Bhaumik, Indranil; Bhatt, R; Saxena, A; Karnal, A K; Gupta, P K

    2017-02-20

    Single crystals of YVO4sub> with different doping concentrations of Yb (1.5, 3.0, 8.0, and 15.0 at. %) and with good crystalline quality (FWHM ∼43-55 arc sec of rocking curve) were grown by the optical floating zone technique. Refractive index measurements were carried out at four wavelengths as a function of temperature. The measurements show that as the doping concentration of Yb is increased, the refractive index varies marginally for ne whereas there is a significant change in the value of no. The thermo-optic coefficient (dn/dT) was found to be positive with a value ∼10-5/°C, which is 1 order higher than that for the undoped YVO4sub> crystal. The thermo-optic coefficient is higher for ne compared to that of no. Also, a set of relations describing the wavelength dependence of the thermo-optic coefficient were established that are useful for calculating the thermo-optic coefficient at any temperature in the range 30°C-150°C and at any wavelength in the range 532-1551 nm.

  17. Local Structural Investigations, Defect Formation, and Ionic Conductivity of the Lithium Ionic Conductor Li 4sub> P 2 S 6

    SciTech Connect

    Dietrich, Christian; Sadowski, Marcel; Sicolo, Sabrina; Weber, Dominik A.; Sedlmaier, Stefan J.; Weldert, Kai S.; Indris, Sylvio; Albe, Karsten; Janek, Jürgen; Zeier, Wolfgang G.

    2016-12-13

    Glassy, glass–ceramic, and crystalline lithium thiophosphates have attracted interest in their use as solid electrolytes in all-solid-state batteries. Despite similar structural motifs, including PS4sub>3–, P2S64–, and P2S74– polyhedra, these materials exhibit a wide range of possible compositions, crystal structures, and ionic conductivities. Here, we present a combined approach of Bragg diffraction, pair distribution function analysis, Raman spectroscopy, and 31P magic angle spinning nuclear magnetic resonance spectroscopy to study the underlying crystal structure of Li4sub>P2S6. In this work, we show that the material crystallizes in a planar structural arrangement as a glass ceramic composite, explaining the observed relatively low ionic conductivity, depending on the fraction of glass content. Calculations based on density functional theory provide an understanding of occurring diffusion pathways and ionic conductivity of this Li+ ionic conductor.

  18. Disorder from order among anisotropic next-nearest-neighbor Ising spin chains in SrHo2O4sub>

    SciTech Connect

    Wen, J. -J.; Tian, W.; Garlea, V. O.; Koohpayeh, S. M.; McQueen, T. M.; Li, H. -F.; Yan, J. -Q.; Rodriguez-Rivera, J. A.; Vaknin, D.; Broholm, C. L.

    2015-02-26

    In this study, we describe why Ising spin chains with competing interactions in SrHo2O4sub> segregate into ordered and disordered ensembles at low temperatures (T). Using elastic neutron scattering, magnetization, and specific heat measurements, the two distinct spin chains are inferred to have Néel (↑↓↑↓) and double-Néel (↑↑↓↓) ground states, respectively. Below TN = 0.68(2)K, the Néel chains develop three-dimensional long range order (LRO), which arrests further thermal equilibration of the double-Néel chains so they remain in a disordered incommensurate state for T below TS = 0.52(2)K. SrHo2O4sub> distills an important feature of incommensurate low dimensional magnetism: kinetically trapped topological defects in a quasi–d–dimensional spin system can preclude order in d + 1 dimensions.

  19. Magnetic excitations from an S=1/2 diamond-shaped tetramer compound Cu2PO4sub>OH

    SciTech Connect

    Matsuda, Masaaki; Dissanayake, Sachith E.; Abernathy, Douglas L.; Totsuka, K.; Belik, A. A.

    2015-11-30

    Inelastic neutron scattering experiments have been carried out on a powder sample of Cu2PO4sub>OH, which consists of diamond-shaped tetramer spin units with S=1/2. We have observed two nearly dispersionless magnetic excitations at E1 ~2 and E2 ~0 meV, whose energy width are broader than the instrumental resolution. The simplest square tetramer model with one dominant interaction, which predicts two sharp excitation peaks at E1 and E2(=2E1), does not explain the experimental result. We found that two diagonal intratetramer interactions compete with the main interaction and weak intertetramer interactions connect the tetramers. The main intratetramer interaction is found to split into two inequivalent ones due to a structural distortion below 160 K. Cu2PO4sub>OH is considered to be a good material to study the S=1/2 Heisenberg tetramer system.

  20. In situ studies of surface of NiFe2O4sub> catalyst during complete oxidation of methane

    SciTech Connect

    Zhang, Shiran; Shan, Junjun; Nie, Longhui; Nguyen, Luan; Wu, Zili; Tao, Franklin

    2015-12-21

    Here, NiFe2O4sub> with an inverse spinel structure exhibits high activity for a complete oxidation of methane at 400 °C–425 °C and a higher temperature. The surface of the catalyst and its adsorbates were well characterized with ambient pressure X-ray photoelectron spectroscopy (AP-XPS) and in situ infrared spectroscopy (IR). In situ studies of the surface of NiFe2O4sub> using AP-XPS suggest the formation of methoxy-like and formate-like intermediates at a temperature lower than 200 °C, supported by the observed vibrational signatures in in situ IR studies. Evolutions of C1s photoemission features and the nominal atomic ratios of C/(Ni + Fe) of the catalyst surface suggest that the formate-like intermediate is transformed to product molecules CO2 and H2O in the temperature range of 250–300 °C. In situ studies suggest the formation of a spectator, – Olattice – CH2 – Olattice –. It strongly bonds to surface through C–O bonds and cannot be activated even at 400 °C.

  1. The effects of cation–anion clustering on defect migration in MgAl2O4sub>

    SciTech Connect

    Zamora, Richard J.; Voter, Arthur F.; Perez, Danny; Perriot, Romain; Uberuaga, Blas P.

    2016-06-28

    Magnesium aluminate spinel (MgAl2O4sub>), like many other ceramic materials, offers a range of technological applications, from nuclear reactor materials to military body armor. For many of these applications, it is critical to understand both the formation and evolution of lattice defects throughout the lifetime of the material. We use the Speculatively Parallel Temperature Accelerated Dynamics (SpecTAD) method to investigate the effects of di-vacancy and di-interstitial formation on the mobility of the component defects. From long-time trajectories of the state-to-state dynamics, we characterize the migration pathways of defect clusters, and calculate their self-diffusion constants across a range of temperatures. We find that the clustering of Al and O vacancies drastically reduces the mobility of both defects, while the clustering of Mg and O vacancies completely immobilizes them. For interstitials, we find that the clustering of Mg and O defects greatly reduces O interstitial mobility, but has only a weak effect on Mg. Lastly, these findings illuminate important new details regarding defect kinetics relevant to the application of MgAl2O4sub> in extreme environments.

  2. Conduction below 100 °C in nominal Li6ZnNb4sub>O14

    SciTech Connect

    Li, Yunchao; Paranthaman, Mariappan Parans; Gill, Lance W.; Edward W. Hagaman; Wang, Yangyang; Sokolov, Alexei P.; Dai, Sheng; Ma, Cheng; Chi, Miaofang; Veith, Gabriel M.; Manthiram, Arumugam; Goodenough, John B.

    2015-09-15

    The increasing demand for a safe rechargeable battery with a high energy density per cell is driving a search for a novel solid electrolyte with a high Li+ or Na+ conductivity that is chemically stable in a working Li-ion or Na-ion battery. Li6ZnNb4sub>O14 has been reported to exhibit a σ Li > 10-2 S cm-1 at 250 °C, but to disproportionate into multiple phases on cooling from 850 °C to room temperature. An investigation of the room-temperature Li-ion conductivity in a porous pellet of a multiphase product of a nominal Li6ZnNb4sub>O14 composition is shown to have bulk σ Li 3.3 x 10-5 S cm-1 at room temperature that increases to 1.4 x 10-4 S cm-1 by 50 °C. 7Li MAS NMR spectra were fitted to two Lorentzian lines, one of which showed a dramatic increase with increasing temperature. As a result, a test for water stability indicates that Li+ may move to the particle and grain surfaces to react with adsorbed water as occurs in the garnet Li+ conductors.

  3. NMR Studies of the Vanadium Spin Dynamics and Spin Structure in LiV2O4sub>, CaV2O4sub>, and (LixV1-x)3BO5 (x ≈ 0.33, 0.40)

    SciTech Connect

    Zong, Xiaopeng

    2007-01-01

    Strong electron correlation is believed to be an essential and unifying factor in diverse properties of condensed matter systems. Ground states that can arise due to electron correlation effects include Mott insulators, heavy fermion, ferromagnetism and antiferromagnetism, spin glasses, and high-temperature superconductivity. The electronic systems in transition metal oxide compounds are often highly correlated. In this thesis, the author presents experimental studies on three strongly correlated vanadium oxide compounds: LiV2O4sub>, (LixV1-x)3BO5, and CaV2O4sub>, which have completely different ground states.

  4. Electron scattering, charge order, and pseudogap physics in La1.6–xNd0.4sub>SrxCuO4sub>: An angle-resolved photoemission spectroscopy study

    SciTech Connect

    Matt, C. E.; Fatuzzo, C. G.; Sassa, Y.; Mansson, M.; Fatale, S.; Bitetta, V.; Shi, X.; Pailhes, S.; Berntsen, M. H.; Kurosawa, T.; Oda, M.; Momono, N.; Lipscombe, O. J.; Hayden, S. M.; Yan, J. -Q.; Zhou, J. -S.; Goodenough, J. B.; Pyon, S.; Takayama, T.; Takagi, H.; Patthey, L.; Bendounan, A.; Razzoli, E.; Shi, M.; Plumb, N. C.; Radovic, M.; Grioni, M.; Mesot, J.; Tjernberg, O.; Chang, J.

    2015-10-27

    We report an angle-resolved photoemission study of the charge stripe ordered La1.6–xNd0.4sub>SrxCuO4sub> (Nd-LSCO) system. A comparative and quantitative line-shape analysis is presented as the system evolves from the overdoped regime into the charge ordered phase. On the overdoped side (x = 0.20), a normal-state antinodal spectral gap opens upon cooling below 80 K. In this process, spectral weight is preserved but redistributed to larger energies. A correlation between this spectral gap and electron scattering is found. A different line shape is observed in the antinodal region of charge ordered Nd-LSCO x = 1/8. Significant low-energy spectral weight appears to be lost. As a result, these observations are discussed in terms of spectral-weight redistribution and gapping originating from charge stripe ordering.

  5. Rietveld refinement, electronic structure and ionic conductivity of Sr{sub 4}La{sub 6}(SiO{sub 4}){sub 6}F{sub 2} and Sr{sub 4}La{sub 6}(SiO{sub 4}){sub 6}O ceramics

    SciTech Connect

    Boughzala, Khaled; Debbichi, Mourad; Njema, Hela; Bouzouita, Khaled

    2016-07-15

    In this paper, we report the effect of the tunnel anions on the ionic conductivity of Strontium-Lanthanum silicate apatites. The Sr{sub 4}La{sub 6}(SiO{sub 4}){sub 6}F{sub 2} and Sr{sub 4}La{sub 6}(SiO{sub 4}){sub 6}O ceramics were prepared by the solid state reaction method. X-ray diffraction, NMR spectroscopy and Raman measurements were performed to investigate the crystal structure and vibrational active modes. Moreover, the electronic structures of the crystals were evaluated by the first-principles quantum mechanical calculation based on the density functional theory. Finally, the ionic conductivity was studied according to the complex impedance method. - Graphical abstract: The relaxed primitive unit cell for Sr{sub 4}La{sub 6}Fap. Display Omitted.

  6. Electrochemically influenced cation inter-diffusion and Co3O4sub> formation on La0.6Sr0.4sub>CoO3 infiltrated into SOFC cathodes

    SciTech Connect

    Song, Xueyan; Lee, Shiwoo; Chen, Yun; Gerdes, Kirk

    2015-06-18

    Nanosized LSC electrocatalyst was infiltrated into a porous scaffold cathode composed of Sm2O3-doped CeO2 (SDC) and La0.6Sr0.4sub>Co0.2Fe0.8O3-δ (LSCF) in a commercial button solid oxide fuel cell (SOFC). To understand the stability of cathodes infiltrated with LSC, the infiltrated composite cells were subjected to both electrochemical operating and thermal aging states at 750 °C for 1500 h. Nanostructure and local chemistry evolution of La0.6Sr0.4sub>CoO3 (LSC) infiltrated cathodes upon operation and aging were investigated by transmission electron microscopy. After operation, the LSC remained a cubic perovskite, and the crystal grains exhibit comparable size to as-infiltrated LSC grains. Inter-diffusion of Fe from the LSCF to a Fe-incorporated LSC layer developed on the LSCF backbone. However, only sharp interfaces were observed between LSC and SDC backbone in the as-infiltrated cathode and such interfaces remain after operation. The infiltrated LSC on the SDC backbone also retains granular particle morphology. Furthermore, newly grown Co3O4sub> nanocrystals were found in the operated cathode. After thermal aging, on the other hand, cation inter-diffusion across the interfaces of the infiltrate particles and the cathode backbones is less than that from the operated cells. Lastly, the following hypothesis is proposed: Co3O4sub> forms on LSC arising from local charge balancing between cobalt and oxygen vacancies.

  7. Diagnostic value of H3F3A mutations in giant cell tumour of bone compared to osteoclast‐rich mimics

    PubMed Central

    Presneau, Nadège; Baumhoer, Daniel; Behjati, Sam; Pillay, Nischalan; Tarpey, Patrick; Campbell, Peter J; Jundt, Gernot; Hamoudi, Rifat; Wedge, David C; Loo, Peter Van; Hassan, A Bassim; Khatri, Bhavisha; Ye, Hongtao; Tirabosco, Roberto; Amary, M Fernanda

    2015-01-01

    Abstract Driver mutations in the two histone 3.3 (H3.3) genes, H3F3A and H3F3B, were recently identified by whole genome sequencing in 95% of chondroblastoma (CB) and by targeted gene sequencing in 92% of giant cell tumour of bone (GCT). Given the high prevalence of these driver mutations, it may be possible to utilise these alterations as diagnostic adjuncts in clinical practice. Here, we explored the spectrum of H3.3 mutations in a wide range and large number of bone tumours (n = 412) to determine if these alterations could be used to distinguish GCT from other osteoclast‐rich tumours such as aneurysmal bone cyst, nonossifying fibroma, giant cell granuloma, and osteoclast‐rich malignant bone tumours and others. In addition, we explored the driver landscape of GCT through whole genome, exome and targeted sequencing (14 gene panel). We found that H3.3 mutations, namely mutations of glycine 34 in H3F3A, occur in 96% of GCT. We did not find additional driver mutations in GCT, including mutations in IDH1, IDH2, USP6, TP53. The genomes of GCT exhibited few somatic mutations, akin to the picture seen in CB. Overall our observations suggest that the presence of H3F3A p.Gly34 mutations does not entirely exclude malignancy in osteoclast‐rich tumours. However, H3F3A p.Gly34 mutations appear to be an almost essential feature of GCT that will aid pathological evaluation of bone tumours, especially when confronted with small needle core biopsies. In the absence of H3F3A p.Gly34 mutations, a diagnosis of GCT should be made with caution. PMID:27499898

  8. Diagnostic value of H3F3A mutations in giant cell tumour of bone compared to osteoclast-rich mimics.

    PubMed

    Presneau, Nadège; Baumhoer, Daniel; Behjati, Sam; Pillay, Nischalan; Tarpey, Patrick; Campbell, Peter J; Jundt, Gernot; Hamoudi, Rifat; Wedge, David C; Loo, Peter Van; Hassan, A Bassim; Khatri, Bhavisha; Ye, Hongtao; Tirabosco, Roberto; Amary, M Fernanda; Flanagan, Adrienne M

    2015-04-01

    Driver mutations in the two histone 3.3 (H3.3) genes, H3F3A and H3F3B, were recently identified by whole genome sequencing in 95% of chondroblastoma (CB) and by targeted gene sequencing in 92% of giant cell tumour of bone (GCT). Given the high prevalence of these driver mutations, it may be possible to utilise these alterations as diagnostic adjuncts in clinical practice. Here, we explored the spectrum of H3.3 mutations in a wide range and large number of bone tumours (n = 412) to determine if these alterations could be used to distinguish GCT from other osteoclast-rich tumours such as aneurysmal bone cyst, nonossifying fibroma, giant cell granuloma, and osteoclast-rich malignant bone tumours and others. In addition, we explored the driver landscape of GCT through whole genome, exome and targeted sequencing (14 gene panel). We found that H3.3 mutations, namely mutations of glycine 34 in H3F3A, occur in 96% of GCT. We did not find additional driver mutations in GCT, including mutations in IDH1, IDH2, USP6, TP53. The genomes of GCT exhibited few somatic mutations, akin to the picture seen in CB. Overall our observations suggest that the presence of H3F3A p.Gly34 mutations does not entirely exclude malignancy in osteoclast-rich tumours. However, H3F3A p.Gly34 mutations appear to be an almost essential feature of GCT that will aid pathological evaluation of bone tumours, especially when confronted with small needle core biopsies. In the absence of H3F3A p.Gly34 mutations, a diagnosis of GCT should be made with caution.

  9. Full-dimensional quantum calculations of vibrational levels of NH4sub>+ and isotopomers on an accurate ab initio potential energy surface

    SciTech Connect

    Hua -Gen Yu; Han, Huixian; Guo, Hua

    2016-03-29

    Vibrational energy levels of the ammonium cation (NH4sub>+) and its deuterated isotopomers are calculated using a numerically exact kinetic energy operator on a recently developed nine-dimensional permutation invariant semiglobal potential energy surface fitted to a large number of high-level ab initio points. Like CH4, the vibrational levels of NH4sub>+ and ND4sub>+ exhibit a polyad structure, characterized by a collective quantum number P = 2(v1 + v3) + v2 + v4sub>. As a result, the low-lying vibrational levels of all isotopomers are assigned and the agreement with available experimental data is better than 1 cm–1.

  10. Redox chemistry of a binary transition metal oxide (AB 2 O 4sub> ): a study of the Cu 2+ /Cu 0 and Fe 3+ /Fe 0 interconversions observed upon lithiation in a CuFe 2 O 4sub> battery using X-ray absorption spectroscopy

    SciTech Connect

    Cama, Christina A.; Pelliccione, Christopher J.; Brady, Alexander B.; Li, Jing; Stach, Eric A.; Wang, Jiajun; Wang, Jun; Takeuchi, Esther S.; Takeuchi, Kenneth J.; Marschilok, Amy C.

    2016-06-06

    Copper ferrite, CuFe2 O 4sub>, is a promising candidate for application as a high energy electrode material in lithium based batteries. Mechanistic insight on the electrochemical reduction and oxidation processes was gained through the first X-ray absorption spectroscopic study of lithiation and delithiation of CuFe2 O 4sub>. A phase pure tetragonal CuFe2 O 4sub> material was prepared and characterized using laboratory and synchrotron X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. We used ex situ X-ray absorption spectroscopy (XAS) measurements to study the battery redox processes at the Fe and Cu K-edges, using X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and transmission X-ray microscopy (TXM) spectroscopies. EXAFS analysis showed upon discharge, an initial conversion of 50% of the copper(II) to copper metal positioned outside of the spinel structure, followed by a migration of tetrahedral iron(III) cations to octahedral positions previously occupied by copper(II). Then, upon charging to 3.5 V, the copper metal remained in the metallic state, while iron metal oxidation to iron(III) was achieved. Our results provide new mechanistic insight regarding the evolution of the local coordination environments at the iron and copper centers upon discharging and charging.

  11. Beta-mecaptoethanol suppresses inflammation and induces adipogenic differentiation in 3T3-F442A murine preadipocytes.

    PubMed

    Guo, Wen; Li, Yahui; Liang, Wentao; Wong, Siu; Apovian, Caroline; Kirkland, James L; Corkey, Barbara E

    2012-01-01

    Preadipocytes are present in adipose tissues throughout adult life that can proliferate and differentiate into mature adipocytes in response to environmental cues. Abnormal increase in adipocyte number or size leads to fat tissue expansion. However, it is now recognized that adipocyte hypertrophy is a greater risk factor for metabolic syndrome whereas fat tissue that continues to produce newer and smaller fat cells through preadipocyte differentiation is "metabolically healthy". Because adipocyte hypertrophy is often associated with increased oxidant stress and low grade inflammation, both are linked to disturbed cellular redox, we tested how preadipocyte differentiation may be regulated by beta-mercaptoethanol (BME), a pharmacological redox regulator and radical scavenger, using murine 3T3-F442A preadipocytes as the cell model. Effects of BME on adipogenesis were measured by microphotography, real-time PCR, and Western analysis. Our data demonstrated that preadipocyte differentiation could be regulated by extracellular BME. At an optimal concentration, BME enhanced expression of adipogenic gene markers and lipid accumulation. This effect was associated with BME-mediated down-regulation of inflammatory cytokine expression during early differentiation. BME also attenuated TNFalpha-induced activation of NFkappaB in differentiating preadipocytes and partially restored TNFalpha-mediated suppression on adipogenesis. Using a non-adipogenic HEK293 cell line transfected with luciferase reporter genes, we demonstrated that BME reduced basal and TNFalpha-induced NFkappaB activity and increased basal and ciglitazone-induced PPARgamma activity; both may contribute to the pro-adipogenic effect of BME in differentiating F442A preadipocytes.

  12. Trichloroethylene-induced gene expression and DNA methylation changes in B6C3F1 mouse liver.

    PubMed

    Jiang, Yan; Chen, Jiahong; Tong, Jian; Chen, Tao

    2014-01-01

    Trichloroethylene (TCE), widely used as an organic solvent in the industry, is a common contaminant in air, soil, and water. Chronic TCE exposure induced hepatocellular carcinoma in mice, and occupational exposure in humans was suggested to be associated with liver cancer. To understand the role of non-genotoxic mechanism(s) for TCE action, we examined the gene expression and DNA methylation changes in the liver of B6C3F1 mice orally administered with TCE (0, 100, 500 and 1000 mg/kg b.w. per day) for 5 days. After 5 days TCE treatment at a dose level of 1000 mg/kg b.w., a total of 431 differentially expressed genes were identified in mouse liver by microarray, of which 291 were up-regulated and 140 down-regulated. The expression changed genes were involved in key signal pathways including PPAR, proliferation, apoptosis and homologous recombination. Notably, the expression level of a number of vital genes involved in the regulation of DNA methylation, such as Utrf1, Tet2, DNMT1, DNMT3a and DNMT3b, were dysregulated. Although global DNA methylation change was not detected in the liver of mice exposed to TCE, the promoter regions of Cdkn1a and Ihh were found to be hypo- and hypermethylated respectively, which correlated negatively with their mRNA expression changes. Furthermore, the gene expression and DNA methylation changes induced by TCE were dose dependent. The overall data indicate that TCE exposure leads to aberrant DNA methylation changes, which might alter the expression of genes involved in the TCE-induced liver tumorgenesis.

  13. Toxicity and carcinogenicity studies of boric acid in male and female B6C3F1 mice.

    PubMed

    Dieter, M P

    1994-11-01

    Toxicity and potential carcinogenicity studies of boric acid were investigated in mice to verify in a second rodent species that this was a noncarcinogenic chemical. Earlier chronic studies in rats indicated boric acid was not a carcinogen. The chemical is nominated for testing because over 200 tons are produced annually, there are multiple uses for the product, and there is potential for widespread human exposure, both orally and dermally. Both sexes of B6C3F1 mice were offered diets mixed with boric acid for 14 days, 13 weeks, or 2 years. Dietary doses used in the acute, 14-day study were 0, 0.62, 1.25, 2.5, 5, and 10%; those in the subchronic, 13-week study were 0, 0.12, 0.25, 0.50, 1, and 2%; and doses in the 2-year, chronic study were 0, 0.25, and 0.50% in the diet. Mortality, clinical signs of toxicity, estimates of food consumption, body weight gain, and histopathologic examination of selected tissues constituted the variables measured. In the 14-day study mortality was proportional to dose and time of exposure in both sexes, occurring in dose groups as low as 2.5% and as early as 7 days of exposure. Body weights were depressed more than 10% below controls in the higher dose groups of both sexes. Mortality in the 13-week study was confined to the two highest dose groups in male mice and to the 2%-dose group in females. Body weight depression from 8 to 23% below those of controls occurred in the 0.50% and higher dose groups of both sexes.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Toxicity and carcinogenicity studies of boric acid in male and female B6C3F1 mice.

    PubMed Central

    Dieter, M P

    1994-01-01

    Toxicity and potential carcinogenicity studies of boric acid were investigated in mice to verify in a second rodent species that this was a noncarcinogenic chemical. Earlier chronic studies in rats indicated boric acid was not a carcinogen. The chemical is nominated for testing because over 200 tons are produced annually, there are multiple uses for the product, and there is potential for widespread human exposure, both orally and dermally. Both sexes of B6C3F1 mice were offered diets mixed with boric acid for 14 days, 13 weeks, or 2 years. Dietary doses used in the acute, 14-day study were 0, 0.62, 1.25, 2.5, 5, and 10%; those in the subchronic, 13-week study were 0, 0.12, 0.25, 0.50, 1, and 2%; and doses in the 2-year, chronic study were 0, 0.25, and 0.50% in the diet. Mortality, clinical signs of toxicity, estimates of food consumption, body weight gain, and histopathologic examination of selected tissues constituted the variables measured. In the 14-day study mortality was proportional to dose and time of exposure in both sexes, occurring in dose groups as low as 2.5% and as early as 7 days of exposure. Body weights were depressed more than 10% below controls in the higher dose groups of both sexes. Mortality in the 13-week study was confined to the two highest dose groups in male mice and to the 2%-dose group in females. Body weight depression from 8 to 23% below those of controls occurred in the 0.50% and higher dose groups of both sexes.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7889889

  15. Dose-, route-, and sex-dependent urinary excretion of phenol metabolites in B6C3F, mice

    SciTech Connect

    Kenyon, E.M.; Seeley, M.E.; Janszen, D.; Medinsky, M.A.

    1995-07-01

    Phenol is the major oxidized metabolite of benzene, a known human leukemogen and ubiquitous environmental pollutant. Unlike benzene, phenol does not induce tumors in mice following oral exposure; benzene also exhibits sex-related differences in genotoxicity to bone marrow cells that are not observed following phenol administration. We studied the urinary excretion of phenol metabolites in mice as a means to further investigate the metabolic basis for differences in benzene- and phenol-induced toxicity. Male and female B6C3F, mice (n = 3/group) were exposed to 15, 40, 100, or 225 {mu}mol [{sup 14}C]phenol/kg by iv tail vein injection (6 {mu}Ci/mouse). First-pass intestinal metabolism of phenol was evaluated by comparison of urinary excretion of phenol metabolites following iv administration with additional groups of male mice that received the same dose levels by oral gavage. Mice were placed in glass metabolism cages, and urine was collected over dry ice for 48 h. Urinary metabolites were separated by high-pressure liquid chromatography (HPLC) and quantified by liquid scintillation spectrometry. Urinary excretion of conjugated metabolites of phenol was dose-dependent in both male and female mice administered phenol by iv injection or gavage. The major urinary metabolites of phenol were phenol sulfate (PS), phenol glucuronide (PG), and hydroquinone glucoronide (HQG). Sulfation was the dominant pathway at all dose levels, but decreased as a percent of the excreted dose with a concomitant increase in glucorodination as the dose level increased. Male mice consistently excreted a higher proportion of phenol as the oxidized conjugated metabolite, HQG, compared to female mice, suggesting that male mice oxidize phenol to hydroquinone more rapidly than female mice. 31 refs., 6 figs., 2 tabs.

  16. Toxicology and carcinogenicity studies of diuretics in F344 rats and B6C3F1 mice. 1. Hydrochlorothiazide.

    PubMed

    Bucher, J R; Huff, J; Haseman, J K; Eustis, S L; Elwell, M R; Davis, W E; Meierhenry, E F

    1990-10-01

    Toxicology and carcinogenesis studies of hydrochlorothiazide, a benzothiadiazide diuretic, were conducted by administering diets containing the drug to both sexes of F344 rats and B6C3F1 mice in 15-day, 13-week and 2-year studies. No rats died during the 15-day or 13-week studies at dietary concentrations of up to 50,000 ppm. Deaths of male mice in the top dose group in the 13-week study were likely to be related to chemical administration. In the prechronic studies, increased nephrosis and mineralization at the kidney corticomedullary junction were the primary toxic effects of hydrochlorothiazide observed in rats. In mice, chemical-related effects included nephrosis and calculi, inflammation and epithelial hyperplasia in the urinary bladder. In 2-year studies using dietary concentrations of 0, 250, 500 and 2000 ppm in rats and 0, 2500 and 5000 ppm in mice, survival of dosed and control groups of rats and mice was similar, as were body weights of mice. Dosed groups of male and female rats were uniformly lighter than controls (up to 25%) throughout the studies. Severe chronic renal disease with secondary parathyroid hyperplasia and fibrous osteodystrophy of the bone were attributed to chemical administration in rats. No neoplasms in rats or female mice or non-neoplastic lesions in mice were associated with hydrochlorothiazide. In high-dose male mice, liver neoplasms were increased but were not considered to be related to hydrochlorothiazide administration because of an unusually low incidence in the control group relative to historical controls.

  17. Crystal structure and magnetic properties of NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl

    SciTech Connect

    Jin Tengteng; Liu Wei; Chen Shuang; Prots, Yurii; Schnelle, Walter; Zhao Jingtai; Kniep, Ruediger; Hoffmann, Stefan

    2012-08-15

    A new copper(II) oxide phosphate chloride, NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl], has been synthesized by flux synthesis. Single-crystal X-ray diffraction data show that the title compound crystallizes in the monoclinic system, space group P2{sub 1}/c (No. 14), with lattice parameters a=8.392(2) A, b=6.3960(10) A, c=16.670(2) A, {beta}=109.470(10) Degree-Sign , V=843.6(3) A{sup 3}, Z=4. The crystal structure is characterized by a complex chain of copper-centered polyhedra running along [0 1 0] which are connected by phosphate tetrahedra. The resulting three-dimensional polyhedra framework exhibits channels filled by additional copper and sodium atoms. Field and temperature dependent measurements of the specific heat and the magnetic susceptibility reveal low-dimensional magnetic behavior. The compound starts to decompose at 700 K under release of oxygen and evaporation of Cu{sup I}Cl as shown by simultaneous thermogravimetry and mass spectrometry. - Graphical abstract: The crystal structure of the new copper(II) phosphate chloride, NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl], exhibits linear chains of copper tetrahedra which show low-dimensional magnetic behavior proven by specific heat and magnetic susceptibility measurements. Highlights: Black-Right-Pointing-Pointer A new copper(II) oxide phosphate chloride, NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl], has been synthesized by flux synthesis. Black-Right-Pointing-Pointer The crystal structure comprises chains of Cu{sub 4}O tetrahedra. Black-Right-Pointing-Pointer Low-dimensional behavior has been proven by magnetic and specific heat measurements. Black-Right-Pointing-Pointer On heating, Cu{sup I}Cl and oxygen are released shown by simultaneous thermogravimetry and mass spectrometry.

  18. Beam quality management by periodic reproduction of wavefront aberrations in end-pumped Nd:YVO4sub> laser amplifiers.

    PubMed

    Liu, Bin; Liu, Chong; Shen, Lifeng; Wang, Chunhua; Ye, Zhibin; Liu, Dong; Xiang, Zhen

    2016-04-18

    A method for beam quality management is presented in a master oscillator power amplifier (MOPA) using Nd:YVO4sub> as the gain medium by extra-cavity periodic reproduction of wavefront aberrations. The wavefront aberration evolution of the intra-cavity beams is investigated for both symmetrical and asymmetrical resonators. The wavefront aberration reproduction process is successfully realized outside the cavity in four-stage amplifiers. In the MOPA with a symmetrical oscillator, the laser power increases linearly and the beam quality hardly changes. In the MOPA with an asymmetrical oscillator, the beam quality is deteriorated after the odd-stage amplifier and is improved after the even-stage amplifier. The wavefront aberration reproduction during the extra-cavity beam propagation in the amplifiers is equivalent to that during the intra-cavity propagation. This solution helps to achieve the effective beam quality management in laser amplifier chains.

  19. Temperature, Oxygen, and Soot-Volume-Fraction Measurements in a Turbulent C2H4sub>-Fueled Jet Flame

    SciTech Connect

    Kearney, Sean P.; Guildenbecher, Daniel Robert; Winters, Caroline; Farias, Paul Abraham; Grasser, Thomas W.; Hewson, John C.

    2015-09-01

    We present a detailed set of measurements from a piloted, sooting, turbulent C 2 H 4 sub>- fueled diffusion flame. Hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (CARS) is used to monitor temperature and oxygen, while laser-induced incandescence (LII) is applied for imaging of the soot volume fraction in the challenging jet-flame environment at Reynolds number, Re = 20,000. Single-laser shot results are used to map the mean and rms statistics, as well as probability densities. LII data from the soot-growth region of the flame are used to benchmark the soot source term for one-dimensional turbulence (ODT) modeling of this turbulent flame. The ODT code is then used to predict temperature and oxygen fluctuations higher in the soot oxidation region higher in the flame.

  20. New insights into the thermodynamic behavior of 2LiBH4sub>-MgH2 composite for hydrogen storage

    SciTech Connect

    Cova, Federico; Ronnebro, Ewa; Choi, Yong-Joon; Gennari, Fabiana; Larochette, Pierre

    2015-06-15

    The composite 2LiBH4sub>:MgH2 has been studied as a possible hydrogen storage material due to its high storage capacity. The present work is directed towards the clarification of the thermodynamic behavior of the system, especially in the temperature region above 400°C. We reveal different reaction paths during hydrogen absorption and desorption at various temperatures which has important implication for applications. At temperatures higher than 413°C, the observation of two different absorption pressure plateaus indicates that two different reactions occur, however, below this temperature there is only one plateau present in the system. During desorption, the double plateau can be observed at temperatures as low as 375°C.

  1. The migration mechanism of transition metal ions in LiNi 0.5 Mn 1.5O4sub>

    SciTech Connect

    Xu, Gui-Liang; Qin, Yan; Ren, Yang; Cai, Lu; An, Ke; Amine, Khalil; Chen, Zonghai

    2015-01-01

    The migration of transition metal ions in the oxygen framework was recently proposed to be responsible for the continuous loss of average working potential of high energy density layered–layered composite cathodes for lithium-ion batteries. The potential migration pathway in a model material, LiNi 0.5 Mn 1.5O4sub> spinel, was investigated using in situ high-energy X-ray diffraction and in situ neutron diffraction during the solid state synthesis process. It was found that the migration of transition metal ions among octahedral sites is possible by using tetrahedral vacancies as intermediate sites. It was also suggested that the number of electrons in 3d orbitals has a significant impact on their mobility in the hosting oxygen framework.

  2. Cw and Q-switched Nd:NaLa(MoO{sub 4}){sub 2} laser noncritical to the temperature drift of the diode pump laser wavelength

    SciTech Connect

    Ushakov, S N; Lis, Denis A; Subbotin, Kirill A; Romanyuk, V A; Shestakov, A V; Ryabochkina, P A; Shestakova, I A; Zharikov, Evgeny V

    2010-08-27

    Lasing in Nd:NaLa(MoO{sub 4}){sub 2} crystals is obtained without stabilisation of the diode pump wavelength. A dependence of the cw laser power (at a wavelength of 1059 nm) on the pump diode temperature is found within a range of 10-458C. It is shown that the variations in the diode temperature within this region change the lasing efficiency no more than by 30%. In the passive Q-switching regime, the experiments were performed under both pulsed and cw pumping. Upon pulsed pumping, the laser energy was 16 {mu}J at the output pulse duration of 11 ns. The laser wavelength was 1059 nm, as well as in the case of cw operation. Upon cw pumping with a power of 1.5 W, laser pulses were obtained with an energy of 15 {mu}J. (lasers)

  3. Efficient self-stimulated Raman scattering with simultaneously self-mode-locking in a diode-pumped Nd:GdVO4sub> laser.

    PubMed

    Li, Zuohan; Peng, Jiying; Yao, Jianquan; Han, Ming; Jiang, Linghong

    2016-11-10

    We demonstrated an efficient diode-pumped picosecond self-Raman Nd:GdVO4sub> laser with the simultaneous processes of stimulated Raman scattering and self-mode-locking in the same crystal. The design of self-mode-locked was theoretically analyzed, and a compact and feasible dual-concave cavity was adopted. The maximum output power of the first-Stokes Raman laser was 736 mW with the repetition rate of 1.51 GHz. In addition, the second-harmonic generation of a yellow laser at 586.5 nm is accomplished with an external LiB3O5 crystal.

  4. Diode-end-pumped Ho, Pr:LiLuF4sub> bulk laser at 2.95  μm.

    PubMed

    Nie, Hongkun; Zhang, Peixiong; Zhang, Baitao; Yang, Kejian; Zhang, Lianhan; Li, Tao; Zhang, Shuaiyi; Xu, Jianqiu; Hang, Yin; He, Jingliang

    2017-02-15

    A diode-end-pumped continuous-wave (CW) and passively Q-switched Ho, Pr:LiLuF4sub> (Ho, Pr:LLF) laser operation at 2.95 μm was demonstrated for the first time, to the best of our knowledge. The maximum CW output power was 172 mW. By using a monolayer graphene as the saturable absorber, the passively Q-switched operation was realized, in which regimes with the highest output power, the shortest pulse duration, and the maximum repetition rate were determined to be 88 mW, 937.5 ns, and 55.7 kHz, respectively. The laser beam quality factor M2 at the maximum CW output power were measured to be Mx2=1.48 and My2=1.47.

  5. 119Sn-NMR investigations on superconducting Ca3Ir4sub>Sn13: Evidence for multigap superconductivity

    SciTech Connect

    Sarkar, R.; Petrovic, C.; Bruckner, F.; Gunther, M.; Wang, Kefeng; Biswas, P. K.; Luetkens, H.; Morenzoni, E.; Amato, A.; Klauss, H. -H.

    2015-09-25

    In this study, we report bulk superconductivity (SC) in Ca3Ir4sub>Sn13 by means of 119Sn nuclear magnetic resonance (NMR) experiments. Two classical signatures of BCS superconductivity in spin-lattice relaxation rate (1/T1), namely the Hebel–Slichter coherence peak just below the Tc, and the exponential decay in the superconducting phase, are evident. The noticeable decrease of 119Sn Knight shift below Tc indicates spin-singlet superconductivity. The temperature dependence of the spin-lattice relaxation rate 119(1/T1) is convincingly described by the multigap isotropic superconducting gap. NMR experiments do not witness any sign of enhanced spin fluctuations.

  6. Multiband Te p Based Superconductivity of Ta4sub>Pd3Te16

    SciTech Connect

    Singh, David J.

    2014-10-06

    We recently discovered that Ta4sub>Pd3Te16 is a superconductor that has been suggested to be an unconventional superconductor near magnetism. Here, we report electronic structure calculations showing that despite the layered crystal structure the material is an anisotropic three-dimensional (3D) metal. The Fermi surface contains prominent one-dimensional (1D) and two-dimensional (2D) features, including nested 1D sheets, a 2D cylindrical section, and a 3D sheet. Moreover, the electronic states that make up the Fermi surface are mostly derived from Te p states with small Ta d and Pd d contributions. This places the compound far from magnetic instabilities. The results are discussed in terms of multiband superconductivity.

  7. Nanoparticles of K{sub 2}Ca{sub 2}(SO{sub 4}){sub 3}:Eu as effective detectors for swift heavy ions

    SciTech Connect

    Salah, Numan; Lochab, S. P.; Kanjilal, D.; Ranjan, Ranju; Habib, Sami S.; Rupasov, A. A.; Aleynikov, V. E.

    2007-09-15

    The modification of thermoluminescence (TL) and photoluminescence (PL) properties of K{sub 2}Ca{sub 2}(SO{sub 4}){sub 3}:Eu nanoparticles by swift heavy ions (SHI), irradiation is studied. Pellets form of the nanomaterials were irradiated by 48 MeV Li{sup 3+}, 75 MeV C{sup 6+}, and 90 MeV O{sup 7+} ion beams. The fluence range is 1x10{sup 9}-1x10{sup 13} ions/cm{sup 2}. The modification in TL glow curves of the nanomaterials irradiated by Li{sup 3+}, C{sup 6+}, and O{sup 7+} ion beams are essentially similar to those induced by {gamma}-ray irradiation. These glow curves have single peaks at around 427 K with a small variation in their positions by around {+-}3 K. The TL intensity of the ion beams irradiated nanomaterials is found to decease, while going from low to high atomic number (Z) ions (i.e., Li{sup 3+}{yields}O{sup 7+}). The TL response curve of the pellets irradiated by Li{sup 3+} ions is linear in the whole range of studied fluences. The curves for C{sup 6+} and O{sup 7+} irradiated samples are linear at lower fluences (1x10{sup 9}-1x10{sup 12} ion/cm{sup 2}) and then saturate at higher fluence. These results for the nanomaterials are much better than that of the corresponding microcrystalline samples irradiated with a Li{sup 3+} ion. The curves were linear up to the fluence 1x10{sup 11} ion/cm{sup 2} and then become sublinear at higher fluences. The TL efficiency values of K{sub 2}Ca{sub 2}(SO{sub 4}){sub 3}:Eu nanoparticles irradiated by 48 MeV Li{sup 3+}, 75 MeV C{sup 6+}, and 90 MeV O{sup 7+} ion beams have been measured relative to {gamma} rays of {sup 60}Co and are found to be 0.515, 0.069, and 0.019, respectively. This value for the Li{sup 3+} ion (0.515) is much higher than that of the corresponding microcrystalline material (0.0014). These superiorities for the nanomaterials make K{sub 2}Ca{sub 2}(SO{sub 4}){sub 3}:Eu nanophosphor a suitable candidate for detecting the doses of swift heavy ions. PL studies on the ion beams irradiated and

  8. One Dimensional(1D)-to-2D Crossover of Spin Correlations in the 3D Magnet ZnMn2O4sub>

    SciTech Connect

    Disseler, S. M.; Chen, Y.; Yeo, S.; Gasparovic, G.; Piccoli, P. M. B.; Schultz, A. J.; Qiu, Y.; Huang, Q.; Cheong, S. -W.; Ratcliff, W.

    2015-12-08

    In this paper we report on the intriguing evolution of the dynamical spin correlations of the frustrated spinel ZnMn2O4sub>. Inelastic neutron scattering and magnetization studies reveal that the dynamical correlations at high temperatures are 1D. At lower temperature, these dynamical correlations become 2D. Surprisingly, the dynamical correlations condense into a quasi 2D Ising-like ordered state, making this a rare observation of two dimensional order on the spinel lattice. Remarkably, 3D ordering is not observed down to temperatures as low as 300 mK. This unprecedented dimensional crossover stems from frustrated exchange couplings due to the huge Jahn-Teller distortions around Mn3+ ions on the spinel lattice.

  9. Calcium hydroxyapatite, Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2} ceramics prepared by aqueous sol-gel processing

    SciTech Connect

    Bogdanoviciene, Irma; Beganskiene, Aldona; Tonsuaadu, Kaia; Glaser, Jochen; Meyer, H.-Juergen . E-mail: juergen.meyer@uni-tuebingen.de; Kareiva, Aivaras . E-mail: aivaras.kareiva@chf.vu.lt

    2006-09-14

    Aqueous sol-gel chemistry routes based on ammonium-hydrogen phosphate as the phosphorus precursor and calcium acetate monohydrate as source of calcium ions have been developed to prepare calcium hydroxyapatite samples with different morphological properties. In the sol-gel processes, an aqueous solutions of ethylene diamine tetra-acetic acid (EDTA) or tartaric acid (TA) as complexing agents were added to the reaction mixture. The monophasic Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2} samples were obtained by calcination of precursor gels for 5 h at 1000 deg. C. The phase transformations, composition and micro-structural features in the polycrystalline samples were studied by thermoanalytical methods (TGA/DTA), infrared spectroscopy (IR), X-ray powder diffraction analysis (XRD) and scanning electron microscopy (SEM). It was shown that adjusting the nature of complexing agent in the aqueous sol-gel processing can be used to control the morphology of the ceramic samples.

  10. Remarkable Stability of Charge Density Wave Order in La1.875Ba0.125CuO4sub>

    SciTech Connect

    Chen, X. M.; Thampy, V.; Mazzoli, C.; Barbour, A. M.; Miao, H.; Gu, G. D.; Cao, Y.; Tranquada, J. M.; Dean, M. P. M.; Wilkins, S. B.

    2016-10-11

    The occurrence of charge-density-wave (CDW) order in underdoped cuprates is now well established, although the precise nature of the CDW and its relationship with superconductivity is not. Theoretical proposals include contrasting ideas such as that pairing may be driven by CDW uctuations or that static CDWs may intertwine with a spatially-modulated superconducting wave function. We test the dynamics of CDW order in La1.875Ba0.125CuO4sub> by using x-ray photon correlation spectroscopy (XPCS) at the CDW wave vector, detected resonantly at the Cu L3-edge. We nd that the CDW domains are strikingly static, with no evidence of signi cant uctuations up to 2 3/4 hours. We discuss the implications of these results for some of the competing theories.

  11. Negative to positive magnetoresistance and magnetocaloric effect in Pr0.6Er0.4sub>Al2

    SciTech Connect

    Pathak, Arjun K.; Gschneidner, Jr., K. A.; Pecharsky, V. K.

    2014-10-13

    We report on the magnetic, magnetocaloric and magnetotransport properties of Pr0.6Er0.4sub>Al2. The title compound exhibits a large positive magnetoresistance (MR) for H ≥ 40 kOe and a small but non negligible negative MR for H ≤ 30 kOe. The maximum positive MR reaches 13% at H = 80 kOe. The magnetic entropy and adiabatic temperature changes as functions of temperature each show two anomalies: a broad dome-like maximum below 20 K and a relatively sharp peak at higher temperature. As a result, observed behaviors are unique among other binary and mixed lanthanide compounds.

  12. Enhanced thermoelectric performance driven by high-temperature phase transition in the phase change material Ge4sub>SbTe5

    SciTech Connect

    Williams, Jared B.; Lara-Curzio, Edgar; Cakmak, Ercan; Watkins, Thomas R.; Morelli, Donald T.

    2015-05-15

    Phase change materials are identified for their ability to rapidly alternate between amorphous and crystalline phases and have large contrast in the optical/electrical properties of the respective phases. The materials are primarily used in memory storage applications, but recently they have also been identified as potential thermoelectric materials. Many of the phase change materials researched today can be found on the pseudo-binary (GeTe)1-x(Sb2Te3)x tie-line. While many compounds on this tie-line have been recognized as thermoelectric materials, here we focus on Ge4sub>SbTe5, a single phase compound just off of the (GeTe)1-x(Sb2Te3)x tie-line, that forms in a stable rocksalt crystal structure at room temperature. We find that stoichiometric and undoped Ge4sub>SbTe5 exhibits a thermal conductivity of ~1.2 W/m-K at high temperature and a large Seebeck coefficient of ~250 μV/K. The resistivity decreases dramatically at 623 K due to a structural phase transition which lends to a large enhancement in both thermoelectric power factor and thermoelectric figure of merit at 823 K. In a more general sense the research presents evidence that phase change materials can potentially provide a new route to highly efficient thermoelectric materials for power generation at high temperature.

  13. Self-powdering and nonlinear optical domain structures in ferroelastic beta'-Gd{sub 2}(MoO{sub 4}){sub 3} crystals formed in glass

    SciTech Connect

    Tsukada, Y.; Honma, T.; Komatsu, T.

    2009-08-15

    Ferroelastic beta'-Gd{sub 2}(MoO{sub 4}){sub 3}, (GMO), crystals are formed through the crystallization of 21.25Gd{sub 2}O{sub 3}-63.75MoO{sub 3}-15B{sub 2}O{sub 3} glass (mol%), and two scientific curious phenomena are observed. (1) GMO crystals formed in the crystallization break into small pieces with a triangular prism or pyramid shape having a length of 50-500 {mu}m spontaneously during the crystallizations in the inside of an electric furnace, not during the cooling in air after the crystallization. This phenomenon is called 'self-powdering phenomenon during crystallization' in this paper. (2) Each self-powdered GMO crystal grain shows a periodic domain structure with different refractive indices, and a spatially periodic second harmonic generation (SHG) depending on the domain structure is observed. It is proposed from polarized micro-Raman scattering spectra and the azimuthal dependence of second harmonic intensities that GMO crystals are oriented in each crystal grain and the orientation of (MoO{sub 4}){sup 2-} tetrahedra in GMO crystals changes periodically due to spontaneous strains in ferroelastic GMO crystals. - Graphical abstract: This figure shows the polarized optical photograph at room temperature for a particle (piece) obtained by a heat treatment of the glass at 590 deg. C for 2 h in an electric furnace in air. This particle was obtained through the self-powdering behavior in the crystallization of glass. The periodic domain structure is observed. Ferroelastic beta'-Gd{sub 2}(MoO{sub 4}){sub 3} crystals are formed in the particle, and second harmonic generations are detected, depending on the domain structure.

  14. Undoped and Ni-doped CoOx surface modification of porous BiVO4sub> photoelectrodes for water oxidation

    SciTech Connect

    Liu, Ya; Guo, Youhong; Schelhas, Laura T.; Li, Mingtao; Ager, Joel W.

    2016-09-29

    Surface modification of photoanodes with oxygen evolution reaction (OER) catalysts is an effective approach to enhance water oxidation kinetics, to reduce external bias, and to improve the energy harvesting efficiency of photoelectrochemical (PEC) water oxidation. Here, the surface of porous BiVO4sub> photoanodes was modified by the deposition of undoped and Ni-doped CoOx via nitrogen flow assisted electrostatic spray pyrolysis. This newly developed atmospheric pressure deposition technique allows for surface coverage throughout the porous structure with thickness and composition control. PEC testing of modified BiVO4sub> photoanodes shows that after deposition of an undoped CoOx surface layer, the onset potential shifts negatively by ca. 420 mV and the photocurrent density reaches 2.01 mA cm–2 at 1.23 vs VRHE under AM 1.5G illumination. Modification with Ni-doped CoOx produces even more effective OER catalysis and yields a photocurrent density of 2.62 mA cm–2 at 1.23 VRHE under AM 1.5G illumination. Furthermore, the valence band X-ray photoelectron spectroscopy and synchrotron-based X-ray absorption spectroscopy results show the Ni doping reduces the Fermi level of the CoOx layer; the increased surface band bending produced by this effect is partially responsible for the superior PEC performance.

  15. Complex conductance of ultrathin La2-xSrxCuO4sub> films and heterostructures

    SciTech Connect

    V. A. Gasparov; Bozovic, I.

    2015-10-23

    We used atomic-layer molecular beam epitaxy to synthesize bilayers of a cuprate metal (La1.55Sr0.45CuO4sub>) and a cuprate insulator (La2CuO4sub>), in which each layer is just one unit cells thick. We have studied the magnetic field and temperature dependence of the complex sheet conductance, σ(ω), of these films. Experiments have been carried out at frequencies between 2 and 50 MHz using the single-spiral coil technique. We found that: (i) the inductive response starts at ΔT = 3 K lower temperatures than Re σ(T), which in turn is characterized by a peak close to the transition, (ii) this shift is almost constant with magnetic field up to 14 mT; (iii) ΔT increases sharply up to 4 K at larger fields and becomes constant up to 8 T; (iv) the vortexdiffusion constant D(T) is not linear with T at low temperatures as in the case of free vortices, but is rather exponential due to pinning of vortex cores, and (v) the dynamic Berezinski–Kosterlitz–Thouless (BKT) transition temperature occurs at the point where Y=(lω/ξ+)2 = 1. As a result, our experimental results can be described well by the extended dynamic theory of the BKT transition and dynamics of bound vortex–antivortex pairs with short separation lengths.

  16. Decoupling of the antiferromagnetic and insulating states in Tb-doped Sr2IrO4sub>

    SciTech Connect

    Wang, J. C.; Aswartham, S.; Ye, Feng; Terzic, J.; Zheng, H.; Haskel, Daniel; Chikara, Shalinee; Choi, Yong; Schlottmann, P.; Custelcean, Radu; Yuan, S. J.; Cao, G.

    2015-12-08

    Sr2IrO4sub> is a spin-orbit coupled insulator with an antiferromagnetic (AFM) transition at TN = 240 K. We report results of a comprehensive study of single-crystal Sr2Ir1-xTbxO4sub> (0≤x≤0.03). This study found that mere 3% (x=0.03) tetravalent Tb4+(4f7) substituting for Ir4+ (rather than Sr2+) completely suppresses the long-range collinear AFM transition but retains the insulating state, leading to a phase diagram featuring a decoupling of magnetic interactions and charge gap. The insulating state at x = 0.03 is characterized by an unusually large specific heat at low temperatures and an incommensurate magnetic state having magnetic peaks at (0.95, 0, 0) and (0, 0.95, 0) in the neutron diffraction, suggesting a spiral or spin density wave order. It is apparent that Tb doping effectively changes the relative strength of the SOI and the tetragonal CEF and enhances the Hund’s rule coupling that competes with the SOI, and destabilizes the AFM state. However, the disappearance of the AFM accompanies no metallic state chiefly because an energy level mismatch for the Ir and Tb sites weakens charge carrier hopping and renders a persistent insulating state. Furthermore, this work highlights an unconventional correlation between the AFM and insulating states in which the magnetic transition plays no critical role in the formation of the charge gap in the iridate.

  17. Magnetocaloric effect of Gd4sub>(BixSb1-x)3 alloy series

    SciTech Connect

    Niu, Xuejun

    1999-01-01

    Alloys from the Gd4sub>(BixSb1-x)3 series were prepared by melting a stoichiometric amounts of pure metals in an induction furnace. The crystal structure is of the anti-Th3P4sub> type (space group I$\\bar{4}$3d) for all the compounds tested. The linear increase of the lattice parameters with Bi concentration is attributed to the larger atomic radius of Bi than that of Sb. Magnetic measurements show that the alloys order ferromagnetically from 266K to 330K, with the ordering temperature increasing with decreasing Bi concentration. The alloys are soft ferromagnets below their Curie temperatures, and follow the Curie-Weiss law above their ordering temperatures. The paramagnetic effective magnetic moments are low compared to the theoretical value for a free Gd3+, while the ordered magnetic moments are close to the theoretical value for Gd. The alloys exhibit a moderate magnetocaloric effect (MCE) whose maxima are located between 270K and 338K and have relatively wide peaks. The peak MCE temperature decreases with decreasing Bi concentration while the peak height increases with decreasing Bi concentration. The Curie temperatures determined from inflection points of heat capacity are in good agreement with those obtained from the magnetocaloric effect. The MCE results obtained from the two different methods (magnetization and heat capacity) agree quite well with each other for all of the alloys in the series.

  18. Enhanced ferromagnetic order in Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} featuring canted [MnO{sub 4}]{sub ∞} spin chains of mixed-valent Mn(III)/Mn(IV). Aliovalent substitution of the Sr{sub 4−x}Ln{sub x}Mn{sup III}{sub 2+x}Mn{sup IV}{sub 1−x}O{sub 3}(GeO{sub 4}){sub 3} solid-solution

    SciTech Connect

    West, J. Palmer; Sulejmanovic, Dino; Becht, Gregory; He, Jian; Hitchcock, Dale; Yan, Yonggao; Hwu, Shiou-Jyh

    2013-10-15

    Crystals of Sr{sub 4−x}Ln{sub x}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} (x=0; x∼0.15 for Ln=La, Pr, Nd, Sm. Eu, Gd, Dy; x∼0.3 for Ln=Gd) were isolated upon using high-temperature, solid-state methods in molten-salt media. These compounds are isostructural with the previously reported Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} (Ln=La, Sm, Gd) series that contains the same [MnO{sub 4}]{sub ∞} spin chains. The synthesis of the Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} (x=0) phase was carried out by a double aliovalent substitution with respect to the Sr{sup 2+} and Ge{sup 4+} ions that replace Na{sup +}/Ln{sup 3+} and As{sup 5+} in Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}, respectively. The title series contains mixed-valent Mn(III)/Mn(IV) and shows a limited range of solid solution, both of which were not observed in the previously reported Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} series. To form the Sr{sub 4−x}Ln{sub x}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} solid solution, one of the Sr{sup 2+} sites, i.e., the original Ln-site in Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}, is partially substituted by Ln{sup 3+} in a statistical disorder of Sr{sub 1−x}/Ln{sub x}. Initial magnetic investigations of selected derivatives reveal higher ferromagnetic ordering temperatures than those reported for the Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} series, presumably attributed to a lesser degree of canting as a result of introducing non-Jahn–Teller Mn{sup 4+} ions. Also intriguing is the observation of multiple anomalies at low temperatures which appear to be of electronic origins. - Graphical abstract: Sr{sub 4−x}Ln{sub x}Mn(III){sub 2+x}Mn(IV){sub 1−x}O{sub 3}(GeO{sub 4}){sub 3}. Display Omitted - Highlights: • Double aliovalent substitution: Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} with respect to Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}. • Solid solution with respect to statistical disorder of Sr{sub 1

  19. Crystal chemistry of anhydrous Li uranyl phosphates and arsenates. II. Tubular fragments and cation-cation interactions in the 3D framework structures of Li{sub 6}[(UO{sub 2}){sub 12}(PO{sub 4}){sub 8}(P{sub 4}O{sub 13})], Li{sub 5}[(UO{sub 2}){sub 13}(AsO{sub 4}){sub 9}(As{sub 2}O{sub 7})], Li[(UO{sub 2}){sub 4}(AsO{sub 4}){sub 3}] and Li{sub 3}[(UO{sub 2}){sub 7}(AsO{sub 4}){sub 5}O

    SciTech Connect

    Alekseev, Evgeny V.; Krivovichev, Sergey V.; Depmeier, Wulf

    2009-11-15

    Single crystals of the new compounds Li{sub 6}[(UO{sub 2}){sub 12}(PO{sub 4}){sub 8}(P{sub 4}O{sub 13})] (1), Li{sub 5}[(UO{sub 2}){sub 13}(AsO{sub 4}){sub 9}(As{sub 2}O{sub 7})] (2), Li[(UO{sub 2}){sub 4}(AsO{sub 4}){sub 3}] (3) and Li{sub 3}[(UO{sub 2}){sub 7}(AsO{sub 4}){sub 5}O)] (4) have been prepared using high-temperature solid state reactions. The crystal structures have been solved by direct methods: 1-monoclinic, C2/m, a=26.963(3) A, b=7.063(1) A, c=19.639(1) A, beta=126.890(4){sup o}, V=2991.2(6) A{sup 3}, Z=2, R{sub 1}=0.0357 for 3248 unique reflections with |F{sub 0}|>=4sigma{sub F}; 2-triclinic, P1-bar, a=7.1410(8) A, b=13.959(1) A, c=31.925(1) A, alpha=82.850(2){sup o}, beta=88.691(2){sup o}, gamma=79.774(3){sup o}, V=3107.4(4) A{sup 3}, Z=2, R{sub 1}=0.0722 for 9161 unique reflections with |F{sub 0}|>=4sigma{sub F}; 3-tetragonal, I4{sub 1}/amd, a=7.160(3) A, c=33.775(9) A, V=1732(1) A{sup 3}, Z=4, R{sub 1}=0.0356 for 318 unique reflections with |F{sub 0}|>=4sigma{sub F}; 4-tetragonal, P4-bar, a=7.2160(5) A, c=14.6540(7) A, V=763.04(8) A{sup 3}, Z=1, R{sub 1}=0.0423 for 1600 unique reflections with |F{sub 0}|>=4sigma{sub F}. Structures of all the phases under consideration are based on complex 3D frameworks consisting of different types of uranium polyhedra (UO{sub 6} and UO{sub 7}) and different types of tetrahedral TO{sub 4} anions (T=P or As): PO{sub 4} and P{sub 4}O{sub 13} in 1, AsO{sub 4} and As{sub 2}O{sub 7} in 2, and single AsO{sub 4} tetrahedra in 3 and 4. In the structures of 1 and 2, UO{sub 7} pentagonal bipyramids share edges to form (UO{sub 5}){sub i}nfinity chains extended along the b axis in 1 and along the a axis in 2. The chains are linked via single TO{sub 4} tetrahedra into tubular units with external diameters of 11 A in 1 and 11.5 A in 2, and internal diameters of 4.1 A in 1 and 4.5 A in 2. The channels accommodate Li{sup +} cations. The tubular units are linked into 3D frameworks by intertubular complexes. Structures of 3 and 4

  20. CARCINOGENICITY OF BROMODICHLOROMETHANE ADMINISTERED IN DRINKING WATER TO MALE F344/N RATS AND B6C3F1 MICE

    EPA Science Inventory

    A life-time exposure study was conducted to assess the carcinogenicity of bromodichloromethane (BDCM) administered in the drinking water to male F344/N rats and B6C3F1 mice. Mouse: Target concentrations of BDCM (dissolved in deionized water containing 0.25% emulphor) were 0.05, ...

  1. Tetrel bond of pseudohalide anions with XH3F (X = C, Si, Ge, and Sn) and its role in SN2 reaction

    NASA Astrophysics Data System (ADS)

    Liu, Mingxiu; Li, Qingzhong; Cheng, Jianbo; Li, Wenzuo; Li, Hai-Bei

    2016-12-01

    The complexes of XH3F⋯ N3-/OCN-/SCN- (X = C, Si, Ge, and Sn) have been investigated at the MP2/aug-cc-pVTZ(PP) level. The σ-hole of X atom in XH3F acts as a Lewis acid forming a tetrel bond with pseudohalide anions. Interaction energies of these complexes vary from -8 to -50 kcal/mol, mainly depending on the nature of X and pseudohalide anions. Charge transfer from N/O/S lone pair to X-F and X-H σ* orbitals results in the stabilization of these complexes, and the former orbital interaction is responsible for the large elongation of X-F bond length and the remarkable red shift of its stretch vibration. The tetrel bond in the complexes of XH3F (X = Si, Ge, and Sn) exhibits a significant degree of covalency with XH3F distorted significantly in these complexes. A breakdown of the individual forces involved attributes the stability of the interaction to mainly electrostatic energy, with a relatively large contribution from polarization. The transition state structures that connect the two minima for CH3Br⋯ N3-complexhave been localized and characterized. The energetic, geometrical, and topological parameters of the complexes were analyzed in the different stages of the SN2 reaction N3- + CH3Br → Br- + CH3N3.

  2. Precipitation Hardening of Laser-Surfaced Layer of Maraging Alloy at the Surface of Steel 3Kh3M3F

    NASA Astrophysics Data System (ADS)

    Stavrev, D. S.; Shcherbakov, V. S.

    2016-09-01

    The structure and fracture behavior of a layer of maraging alloy deposited by laser surfacing on steel 3Kh3M3F is studied in the initial condition and after precipitation hardening at 550 and 600°C. Microhardness is measured in layer cross sections, and fractures after surfacing and aging are analyzed in an electron microscope.

  3. Search and Rescue Aircrewman/HH3F Flight Mechanic, 2-10. Military Curriculum Materials for Vocational and Technical Education.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This self-paced, individualized course, adapted from military curriculum materials for use in vocational and technical education, teaches students the skills needed to become a qualified avionics worker on the HH-3F helicopter. The course materials consist of three pamphlets: two student workbooks and a composite ground/flight syllabus. Each…

  4. COMMENT: Comment on 'A summation formula for Clausen's series 3F2(1) with an application to Goursat's function 2F2(x)'

    NASA Astrophysics Data System (ADS)

    Kim, Yong Sup; Rathie, Arjun K.

    2008-02-01

    In a recent paper, Miller (2005 J. Phys. A: Math. Gen. 38 3541-5) obtained a new summation formula for the Clausen's series 3F2(1). The aim of this comment is to point out that the summation formula obtained by Miller is not a new one.

  5. THE INDUCTION OF HEPATOCELLULAR NEOPLASIA BY TRICHLOROACETIC ACID ADMINISTERED IN THE DRINKING WATER OF THE MALE B6C3F1 MOUSE

    EPA Science Inventory

    Summary What is the study? The study is a chronic bioassay (2 years) of trichloroacetic acid, a drinking water disinfection by-product, in the male B6C3F1 mouse.
    What is the impact to the field and the Agency?
    The impact of this study will derive from the use of...

  6. Tunneling splittings in vibronic energy levels of CD3F+ (X∼2 E) studied by high resolution photoelectron spectroscopy and ab initio calculation

    NASA Astrophysics Data System (ADS)

    Dai, Zuyang; Sun, Wei; Wang, Jia; Mo, Yuxiang

    2015-05-01

    The energy levels of CD3F+ (X∼2 E) have been measured up to 1400 cm-1 above the ground vibrational state using the one-photon zero-kinetic energy photoelectron (ZEKE) spectroscopic method. The spin-vibronic energy levels have also been calculated using an ab initio diabatic model. The potential energy surfaces of CD3F+ were calculated from those of CH3F+ using a transformation of the normal coordinates. The calculations show that tunneling splittings of vibrational energy levels exist due to the three equivalent wells caused by the linear-plus-strong quadratic Jahn-Teller coupling. The splittings are smaller than those in CH3F+. The experimental spectrum was assigned based on the fundamental vibrational modes calculated at the energy minimum. The calculated spin-vibronic energy levels are in good agreement with the experimental data. The tunneling splitting pairs for the fundamental vibrations related to the CD3 rock were observed. The first adiabatic ionization energy was determined as 101 534 ± 3 cm-1 or 12.5886 ± 0.0004 eV.

  7. Application of the explicitly correlated coupled-cluster models CCSD(F12*) and CC3(F12*) to the hyperpolarizability of the Ne atom

    SciTech Connect

    Hanauer, Matthias; Köhn, Andreas

    2015-01-22

    This work demonstrates the performance of the recently proposed explicitly correlated coupled-cluster method CCSD(F12*) and a new method using explicitly correlated triple excitations, CC3(F12*), in the calculation of the static ESHG hyperpolarizability of the Ne atom.

  8. KY3F10:Er3+/Yb3+ nanocrystals doped laser-induced self-written waveguide for optical amplification in the C-band

    NASA Astrophysics Data System (ADS)

    Xue, Xiaojie; Cheng, Tonglei; Suzuki, Takenobu; Ohishi, Yasutake

    2016-02-01

    We successfully synthesized Er3+/Yb3+ co-doped KY3F10 nanocrystals by a facile hydrothermal method. The average size of the as-prepared nanocrystals was about 60 nm based on the observation of scanning electron microscope. Under the excitation of a 976 nm laser, the Er3+/Yb3+ doped KY3F10 nanocrystals showed intense near-infrared emission band centered at 1539 nm. The optimal concentrations of Er3+ were carefully selected according to the quantum yield measurement for a stronger emission in the C-band. The as-prepared nanocrystals were dispersed into a monomer, bisphenol A ethoxylate diacrylates, in which self-written waveguides can be fabricated under the irradiation of an induced laser at 450 nm. The KY3F10: Er3+/Yb3+ nanocrystals embedded polymer waveguide were fabricated by laser-induced self-written technique. Two pieces of single mode fiber were well connected with the waveguide in the fabrication procedure. Under a 976 nm laser pumping, amplified spontaneous emission at 1539 nm was observed in the KY3F10: Er3+/Yb3+ nanocrystals doped waveguide.

  9. Properties of a new, efficient, blue-emitting material for applications in upconversion displays: Yb, Tm:KY3F10.

    PubMed

    Rapaport, Alexandra; Milliez, Janet; SzipOcs, Ferenc; Bass, Michael; Cassanho, Arlete; Jenssen, Hans

    2004-12-10

    The properties of Yb, Tm:KY3F1o, a cubic fluoride crystal, are described that make it attractive as the blue emitter in two-dimensional photonic displays. Its peak excitation wavelength for blue upconversion emission is 974.7 nm, where efficient diode laser pump sources are available. The maximum upconversion efficiency measured thus far is 4.4%.

  10. Tunneling Splittings in Vibronic Structure of CH_3F^+ ( X^2E): Studied by High Resolution Photoelectron Spectra and AB Initio Theoretical Method

    NASA Astrophysics Data System (ADS)

    Mo, Yuxiang; Gao, Shuming; Dai, Zuyang; Li, Hua

    2013-06-01

    We report a combined experimental and theoretical study on the vibronic structure of CH_3F^+. The results show that the tunneling splittings of vibrational energy levels occur in CH_3F^+ due to the Jahn-Teller effect. Experimentally, we have measured a high resolution ZEKE spectrum of CH_3F up to 3500 cm^-^1 above the ground state. Theoretically, we performed an ab initio calculation based on the diabatic model. The adiabatic potential energy surfaces (APES) of CH_3F^+ have been calculated at the MRCI/CAS/avq(t)z level and expressed by Taylor expansions with normal coordinates as variables. The energy gradients for the lower and upper APES, the derivative couplings between them and also the energies of the APES have been used to determine the coefficients in the Taylor expansion. The spin-vibronic energy levels have been calculated by accounting all six vibrational modes and their couplings. The experimental ZEKE spectra were assigned based on the theoretical calculations. W. Domcke, D. R. Yarkony, and H. Köpple (Eds.), Conical Intersections: Eletronic Structure, Dynamics and Spectroscopy (World Scientific, Singapore, 2004). M. S. Schuurman, D. E. Weinberg, and D. R. Yarkony, J. Chem. Phys. 127, 104309 (2007).

  11. EFFECT OF TRICHLOROETHYLENE ON DNA METHYLATION AND EXPRESSION OF EARLY-INTERMEDIATE PROTOONCOGENES IN THE LIVER OF B6C3F1 MICE. (R825384)

    EPA Science Inventory

    Trichloroethylene (TCE) is a multimedia environmental pollution that is carcinogenic in mouse liver. The ability of TCE to modulate DNA methylation and the expression of immediate-early protooncogenes was evaluated. Female B6C3F1 mice were administered 1000 mg/kg TCE by gavage 5 ...

  12. De novo mutation in X-linked hearing loss-associated POU3F4 in a sporadic case of congenital hearing loss

    PubMed Central

    Moteki, Hideaki; Shearer, A Eliot; Izumi, Shuji; Kubota, Yamato; Azaiez, Hela; Booth, Kevin T; Sloan, Christina M; Kolbe, Diana L; Smith, Richard JH; Usami, Shin-ichi

    2015-01-01

    Objective In this report, we present a male patient with no family history of hearing loss, in whom we identified a novel de novo mutation in the POU3F4 gene. Methods One hundred ninety-four (194) Japanese subjects from unrelated and families were enrolled in this study. We used targeted genomic enrichment and massively parallel sequencing of all known non-syndromic hearing loss genes for identifying the genetic causes of hearing loss. Results A novel de novo frameshift mutation of POU3F4, to c.727_728insA (p.N244KfsX26) was identified. The patient was a 7-year-old male with congenital progressive hearing loss and inner ear deformity. Although the patient had received a cochlear implant, auditory skills were still limited. The patient also exhibited developmental delays similar to those previously associated with POU3F4 mutation. Conclusion This is the first report of a mutation in POU3F4 causing hearing loss in a Japanese patient without a family history of hearing loss. This study underscores the importance of comprehensive genetic testing of patients with hearing loss for providing accurate prognostic information and guiding the optimal management of patient rehabilitation. PMID:25792666

  13. Theoretical and experimental analyses of the synergism in the dielectric strength for C3F8/C2HF5 mixtures

    NASA Astrophysics Data System (ADS)

    Larin, A. V.; Meurice, N.; Gentils, F.; Fievet, C.; Vercauteren, D. P.

    2007-04-01

    Two theoretical approaches are applied in order to describe the behavior of the experimental breakdown voltage in C3F8/C2HF5 mixtures. First, available cross section data of the electron-molecule processes are scaled to simulate the dielectric strength (DS) behavior in both C3F8 and C2HF5 gases at the level of the Boltzmann equation (BE) solution corresponding to a homogeneous electric field model. Then, the DS of C3F8/C2HF5 mixtures is evaluated and compared to the experimental breakdown voltage measured using different electrode geometries as sphere/plane type via experimental techniques, i.e., power frequency and negative or positive polarity lightning impulse. Due to the limitation of the BE approach to describe the observed experimental data, the Hunter-Christophorou [J. Appl. Phys. 57, 4377 (1985)] model regarding the positive synergism phenomenon is finally applied. Both models allow us to compare relative values of the "chemical" and "physical" DS components in C3F8/C2HF5 mixtures.

  14. The vitreous after C3F8 gas instillation: long-term histologic findings after spontaneous reabsorption of the gas in rabbit eyes.

    PubMed

    Faulborn, J; Bowald, S

    1987-01-01

    Perfluoropropane gas (C3F8) was injected intravitreally into rabbit eyes to displace the vitreous. Histologic examination by light and scanning electron microscopy revealed the vitreous material slowly expanded up to a nearly normal configuration during a follow-up of 6 months. Neither posterior vitreous detachment nor liquefaction of the vitreous could be observed.

  15. MINDO Forces Study of the Uncatalysed and Acid-Catalysed Friedel-Crafts Reactions Between CH3F and CH4

    NASA Astrophysics Data System (ADS)

    Abed, Amel G.; Khalil, Salim M.

    1999-04-01

    MINDO-forces calculations have been performed on the uncatalysed and acid-catalysed Friedel-Crafts reaction between CH3F and CH4 . It has been found that the catalysed reaction is exothermic, spontaneous and has a smaller potential-energy barrier than the uncatalysed reaction. The mechanisms for uncatalysed and catalysed reactions are discussed.

  16. EVALUATION OF THE IMMUNOMODULATORY EFFECTS OF THE DISINFECTION BYPRODUCT, SODIUM CHLORITE, IN FEMALE B6C3F1 MICE: A DRINKING WATER STUDY

    EPA Science Inventory

    Evaluation of the Immunomodulatory Effects of the Disinfection By-product, Sodium chlorite, in Female B6C3f1 mice: A Drinking Water Study.

    Niel A. Karrow, Tal, L. Guo, J. Ann McCay, Greg W. Johnson, Ronnetta D. Brown, Debrorah L. Musgrove, Dori R. Germolec, Robert W. Lueb...

  17. Self-organized homo-epitaxial growth in nonlinear optical BaAlBO3F2 crystal crossing lines patterned by laser in glass

    NASA Astrophysics Data System (ADS)

    Shinozaki, K.; Abe, S.; Honma, T.; Komatsu, T.

    2015-11-01

    Crystallization processing of glasses is important as a novel technique for the development of new optical materials, and laser-induced crystallization provides a new challenge in science and technology of materials. Nonlinear optical BaAlBO3F2 crystal lines with crossing, bending, and spiral shapes were patterned at the surface of 2NiO-49BaF2-24.5Al2O3-24.5B2O3 (mol%) and 2.9NiO-48.5BaF2-24.3Al2O3-24.3B2O3 (mol%) glasses by laser irradiation (Yb:YVO4 laser with a wavelength of 1080 nm) and the orientation state of BaAlBO3F2 crystals was examined from birefringence image observations. The birefringence images indicate that the growth of highly c-axis oriented BaAlBO3F2 crystals follows along the laser scanning direction even if the laser scanning direction changes, and in particular the direction of the c-axis of BaAlBO3F2 crystals changes gradually at the crossing and bending points. The model of "self-organized homo-epitaxial growth" is proposed for the crystal orientation at the crossing and bending points, as a new crystal growth science and engineering beyond the wise providence of nature.

  18. Toxicity of furfuryl alcohol to F344 rats and B6C3F1 mice exposed by inhalation.

    PubMed

    Irwin, R D; Chou, B J; Mellick, P W; Miller, R A; Mahler, J; Roycroft, J

    1997-01-01

    Groups of F344 rats and B6C3F1 mice were exposed to furfuryl alcohol vapor for 6 hours per day, 5 days per week for 14 days (0, 16, 31, 63, 125, 250 ppm) or 13 weeks (0, 2, 4, 8, 16, 32 ppm). Reduced survival was observed in the 14-day study at 250 ppm. Final mean body weights of rats and mice exposed to 125 ppm and of female mice exposed to 63 ppm were lower than controls at the end of the 14-day study; there were no significant differences in mean body weight among chemical-exposed and control groups in the 13-week study. Exposure to furfuryl alcohol had no toxicologically significant effect on organ weights in either rats or mice, and did not cause any adverse changes in hematology or serum chemistry parameters evaluated in rates in the 13-week study. Microscopic lesions associated with exposure to furfuryl alcohol were present in the nose of both rats and mice at all exposure concentrations in both the 14-day and 13-week studies. Lesions observed in the 14-day study consisted of inflammation of the nasal turbinates accompanied by necrosis and squamous metaplasia of the respiratory epithelium and necrosis and degeneration of the olfactory epithelium. Similar lesions were observed in both rats and mice in the 13-week study. In addition, squamous metaplasia and goblet cell hyperplasia of the respiratory epithelium, squamous metaplasia of the transitional epithelium and degeneration, hyperplasia and some respiratory metaplasia of the olfactory epithelium were also observed in rats in the 13-week study, and hyaline droplets in the respiratory epithelium and chronic inflammation and respiratory metaplasia in the olfactory epithelium were observed in mice in the 13-week study. In general the nasal passages of mice appeared less sensitive than those of rats at the concentrations used in the 13-week study; a no-observable-effect level was not achieved in either the 14-day or the 13-week study.

  19. Global trends and annual releases of CCl3F and CCl2F2 estimated from ALE/GAGE and other measurements from July 1978 to June 1991

    NASA Technical Reports Server (NTRS)

    Cunnold, D. M.; Fraser, P. J.; Weiss, R. F.; Prinn, R. G.; Simmonds, P. G.; Miller, B. R.; Alyea, F. N.; Crawford, A. J.

    1994-01-01

    Thirteen years of Atmospheric Lifetime Experiment/Global Atmospheric Gases Experiment CCl3F and CCl2F2 measurements at five remote, surface, globally distributed sites are analyzed. Comparisons are made against shipboard measurements by the Scripps Institution of Oceanography (SIO) group and archived air samples collected at Cape Grim, Tasmania, since 1978. CCl3F in the lower troposphere was increasing at an average rate of 9.2 ppt/yr over the period July 1978 to June 1988. CCl2F2 was increasing at an average 17.3 ppt/yr in the lower troposphere over the same period. However, between July 1988 and June 1991 the increases of CCl3F and CCl2F2 in this region have averaged just 7.0 ppt/yr and 15.7 ppt/yr, respectively. The rate of increase has been decreasing 2.4 ppt/yr(exp 2) and 2.9 ppt/yr(exp 2) over this 3-year period. Based on a recent scenario of the global releases of these compounds and using the new calibration scale SIO 1993, the equilibrium lifetimes are estimated to be 44 +17/-10 and 180 +820/-81 years for CCl3F and CCl2F2, respectively. Using these lifetime estimates and a two-dimensional model, it is estimated that global releases of these two chlorofluorocarbons in 1990 were 249 +/- 28 x 10(exp 6) kg for CCl3F and 366 +/- 30 x 10(exp 6) kg for CCl2F2. It is also estimated that combined releases of these chlorofluorocarbons in 1990 were 21 +/- 5% less than those in 1986.

  20. Distinct roles for Sema3A, Sema3F, and an unidentified trophic factor in controlling the advance of geniculate axons to gustatory lingual epithelium.

    PubMed

    Vilbig, Ryan; Cosmano, Jason; Giger, Roman; Rochlin, M William

    2004-12-01

    Geniculate ganglion axons arrive in the lingual mesenchyme on embryonic day 13 (E13), 3-4 days before penetrating fungiform papilla epithelium (E17). This latency may result from chemorepulsion by epithelial Sema3A (Dillon et al. (2004) Journal of Comparative Neurology 470, 13-24), or Sema3F, which we report is also expressed in this epithelium. Sema3A and Sema3F repelled or suppressed geniculate neurite outgrowth, respectively, and these effects were stage and neurotrophic factor dependent. BDNF-stimulated outgrowth is repelled by Sema3A until E17, but insensitive to Sema3F from E16. NT-4-stimulated neurite outgrowth is sensitive to Sema3A and Sema3F through E18, but NT-4 has not been detected in E15-18 tongue. E15-18 tongue explants did not exhibit net chemorepulsion of geniculate neurites, but the ability of tongue explants to support geniculate neurite outgrowth fluctuates: E12-13 (Rochlin et al. (2000), Journal of Comparative Neurology, 422, 579-593) and E17-18 explants promote and may attract geniculate neurites, but stages corresponding to intralingual arborization do not. The E18 trophic and tropic effects were evident even in the presence of BDNF or NT-4, suggesting that some other factor is responsible. Intrinsic neurite outgrowth capability (without exogenous neurotrophic factors) fluctuated similarly: ganglia deteriorated at E15, but exhibited moderate outgrowth at E18. The chemorepulsion studies are consistent with a role for Sema3A, not Sema3F, in restricting geniculate axons from the epithelium until E17, when axons penetrate the epithelium. The transient inability of tongue explants to promote geniculate neurite outgrowth may signify an alternative mechanism for restricting geniculate axons from the epithelium: limiting trophic factor access.

  1. Non-mitogenic Anti-CD3F(ab′)2 Monoclonal Antibody: A Novel Approach to Control Herpetic Stromal Keratitis

    PubMed Central

    Sarangi, Pranita P.; Kim, Bumseok; Rouse, Barry T.

    2008-01-01

    Purpose Treatment with anti-CD3 antibody has been shown to ameliorate and reverse an existing immunopathological condition by inducing tolerance. The purpose of this study is to assess the therapeutic potential of non-Fc receptor (FcR) binding anti-CD3 monoclonal antibody (mAb), CD3F(ab′)2, for the treatment of herpes simplex virus (HSV)-induced stromal keratitis (SK). Methods Balb/c and C57BL/6 mice were ocularly infected with HSV-1 strain RE (HSV-1RE). Infected animals were treated with CD3F(ab′)2. Development of SK starting from day 5 postinfection (p.i.), infiltration of inflammatory cells into the corneas and the generation of the immune response were compared with untreated animals using slit-lamp biomicroscopy, flow cytometry, and ELISA. Results In vivo administration of CD3F(ab′)2 resulted in significant reduction in the severity and incidence of SK in the infected animals compared to untreated counterparts. Infiltration of fewer pathogenic CD4+ T cells into the cornea, along with a lower percentage of cells that could be induced to express IFN-γ, occurred with anti-CD3F(ab′)2 treatment. Similar observations were noted in the secondary lymphoid tissues. Additionally, an increase in the frequency of CD4+Foxp3+ regulatory T cells was noticed in both cornea and lymphoid tissues of treated animals compared to untreated animals. Treatment with CD3F(ab′)2 also reduced the number of SSIE-FARL peptide-specific CD8+IFN-γ+ T cells in the secondary lymphoid tissues. Furthermore, use of this reagent was moderately effective in limiting lesions in mice with established lesions. Conclusions Taken together, these results show that non-FcR binding anti-CD3 treatment could be useful in limiting SK lesions. PMID:18689698

  2. Behavior of BrO3F and ClO3F toward strong Lewis acids and the characterization of [XO2][SbF6] (X = Cl, Br) by single crystal X-ray diffraction, Raman spectroscopy, and computational methods.

    PubMed

    Lehmann, John F; Riedel, Sebastian; Schrobilgen, Gary J

    2008-09-15

    The interactions of BrO3F and ClO3F with the strong Lewis acids AsF5 and SbF5 were investigated. Although ClO3F is unreactive toward AsF5 and SbF5, BrO3F undergoes fluoride ion abstraction and O2 elimination, accompanied by central halogen reduction, to form [BrO2][Sb(n)F(5n+1)] (n > or = 1), rather than simple fluoride ion abstraction to form BrO3(+) salts. The geometric parameters of the BrO2(+) cation have been obtained in the solid state for the first time by a single-crystal X-ray diffraction study of [BrO2][SbF6] at -173 degrees C and are compared with those of ClO2(+) salts. Quantum-chemical calculations have been used to arrive at the geometries and vibrational frequencies of XO2(+) and XO3(+) (X = Cl, Br) and have been compared with the experimental values for XO2(+). The calculations have also been used to account for the contrasting behaviors of ClO3F and BrO3F toward central halogen reduction in the presence of liquid SbF5. The thermochemical stabilities of ClO3(+) and BrO3(+) salts of the AsF6(-), SbF6(-), Sb2F11(-), and Sb3F16(-) were also investigated, which provided the fluoride ion affinities of AsF5, SbF5, Sb2F10, and Sb3F15 up to and including the CCSD(T) level of theory. These values are compared with the current literature values. Thermochemical studies indicate that XO3(+) formation by fluoride ion abstraction from XO3F is not spontaneous under standard conditions whereas a concerted fluoride abstraction and O2 elimination to give the XO2(+) cations is spontaneous to near thermally neutral. Failure to observe reactivity between ClO3F and any of the aforementioned Lewis acid fluoride ion acceptors is attributed to a significant kinetic barrier to fluoride ion abstraction.

  3. Color-tunable photoluminescence and energy transfer properties of single-phase Ba{sub 10}(PO{sub 4}){sub 6}O:Eu{sup 2+}, Mn{sup 2+} phosphors

    SciTech Connect

    Guo, Qingfeng; Liao, Libing Mei, Lefu Liu, Haikun

    2015-12-15

    Single-phase Ba{sub 10−x−y}(PO{sub 4}){sub 6}O:xEu{sup 2+},yMn{sup 2+} samples with apatite structure have been synthesized via a solid-state reaction method. The phase structure, luminescence properties, lifetime, PL thermal stability, as well as fluorescence decay curves of the samples were investigated. Effective energy transfer occurs from Eu{sup 2+} to Mn{sup 2+} in Ba{sub 10}(PO{sub 4}){sub 6}O and a possible mechanism of the energy-transfer from Eu{sup 2+} to Mn{sup 2+} is proposed. The critical distances R{sub c} was calculated by concentration quenching and turned out to be about 0.817 nm (x{sub c}=0.21). The CIE and thermally stable luminescence behaviors of Ba{sub 9.94}(PO{sub 4}){sub 6}O:0.06Eu{sup 2+} phosphor were also studied in detail. All the results indicate that Ba{sub 10−x−y}(PO{sub 4}){sub 6}O:xEu{sup 2+}, yMn{sup 2+} phosphors have potential applications as near UV-convertible phosphors for white light-emitting diodes. - Graphical abstract: Crystal structure and luminescence property of Ba{sub 10−x−y}(PO{sub 4}){sub 6}O:xEu{sup 2+},yMn{sup 2+} have been discussed. - Highlights: • Ba{sub 10−x−y}(PO{sub 4}){sub 6}O:xEu{sup 2+},yMn{sup 2+} was firstly reported. • Ba{sub 9.94}(PO{sub 4}){sub 6}O:0.06Eu{sup 2+} exhibits high thermal quenching resistance. • The energy transfer between Eu{sup 2+} and Mn{sup 2+} was investigated.

  4. Operando identification of the point of [Mn-2]O-4sub> spinel formation during gamma-MnO2 discharge within batteries

    SciTech Connect

    Gallaway, Joshua W.; Hertzberg, Benjamin J.; Zhong, Zhong; Croft, Mark; Turney, Damon E.; Yadav, Gautam G.; Steingart, Daniel A.; Erdonmez, Can K.; Banerjee, Sanjoy

    2016-05-07

    The rechargeability of γ-MnO2 cathodes in alkaline batteries is limited by the formation of the [Mn2]O4sub> spinels ZnMn2O4sub> (hetaerolite) and Mn3O4sub> (hausmannite). However, the time and formation mechanisms of these spinels are not well understood. Here we directly observe γ-MnO2 discharge at a range of reaction extents distributed across a thick porous electrode. Coupled with a battery model, this reveals that spinel formation occurs at a precise and predictable point in the reaction, regardless of reaction rate. Observation is accomplished by energy dispersive X-ray diffraction (EDXRD) using photons of high energy and high flux, which penetrate the cell and provide diffraction data as a function of location and time. After insertion of 0.79 protons per γ-MnO2 the α-MnOOH phase forms rapidly. α-MnOOH is the precursor to spinel, which closely follows. ZnMn2O4sub> and Mn3O4sub> form at the same discharge depth, by the same mechanism. The results show the final discharge product, Mn3O4sub> or Mn(OH)2, is not an intrinsic property of γ-MnO2. While several studies have identified Mn(OH)2 as the final γ-MnO2 discharge product, we observe direct conversion to Mn3O4sub> with no Mn(OH)2.

  5. Expanding the Chemistry of Actinide Metallocene Bromides. Synthesis, Properties and Molecular Structures of the Tetravalent and Trivalent Uranium Bromide Complexes: (C5Me4sub>R)2UBr2, (C5Me4sub>R)2U(O-2,6-iPr2C6H3)(Br), and [K(THF)][(C5Me4sub>R)2UBr2] (R = Me, Et)

    SciTech Connect

    Lichtscheidl, Alejandro Gaston; Pagano, Justin K.; Scott, Brian Lindley; Nelson, Andrew Thomas; Kiplinger, Jaqueline Loetsch

    2016-01-06

    The organometallic uranium species (C5Me4sub>R)2UBr2 (R = Me, Et) were obtained by treating their chloride analogues (C5Me4sub>R)2UCl2 (R = Me, Et) with Me3SiBr. Treatment of (C5Me4sub>R)2UCl2 and (C5Me4sub>R)2UBr2 (R = Me, Et) with K(O-2,6-iPr2C6H3) afforded the halide aryloxide mixed-ligand complexes (C5Me4sub>R)2U(O-2,6-iPr2C6H3)(X) (R = Me, Et; X = Cl, Br). Complexes (C5Me4sub>R)2U(O-2,6-iPr2C6H3)(Br) (R = Me, Et) can also be synthesized by treating (C5Me4sub>R)2U(O-2,6-iPr2C6H3)(Cl) (R = Me, Et) with Me3SiBr, respectively. Reduction of (C5Me4sub>R)2UCl2 and (C5Me4sub>R)2UBr2 (R = Me, Et) with KC8 led to isolation of uranium(III) “ate” species [K(THF)][(C5Me5)2UX2] (X = Cl, Br) and [K(THF)0.5][(C5Me4sub>Et)2UX2] (X = Cl, Br), which can be converted to the neutral complexes (C5Me4sub>R)2U[N(SiMe3)2] (R = Me, Et). Analyses by nuclear magnetic resonance spectroscopy, X-ray crystallography, and elemental analysis are also presented.

  6. Insight into the Atomic Structure of High-Voltage Spinel LiNi0.5Mn1.5O4sub> Cathode Material in the First Cycle

    SciTech Connect

    Huang, Xuejie; Yu, Xiqian; Lin, Mingxiang; Ben, Liubin; Sun, Yang; Wang, Hao; Yang, Zhenzhong; Gu, Lin; Yang, Xiao -Qing; Zhao, Haofei; Yu, Richeng; Armand, Michel

    2014-12-22

    Application of high-voltage spinel LiNi0.5Mn1.5O4sub> cathode material is the closest and the most realistic approach to meeting the midterm goal of lithium-ion batteries for electric vehicles (EVs) and plug-in hybrid electric vehicles (HEVs). However, this application has been hampered by long-standing issues, such as capacity degradation and poor first-cycle Coulombic efficiency of LiNi0.5Mn1.5O4sub> cathode material. Although it is well-known that the structure of LiNi0.5Mn1.5O4sub> into which Li ions are reversibly intercalated plays a critical role in the above issues, performance degradation related to structural changes, particularly in the first cycle, are not fully understood. Here, we report detailed investigations of local atomic-level and average structure of LiNi0.5Mn1.5O4sub> during first cycle (3.5–4.9 V) at room temperature. We observed two types of local atomic-level migration of transition metals (TM) ions in the cathode of a well-prepared LiNi0.5Mn1.5O4sub>//Li half-cell during first charge via an aberration-corrected scanning transmission electron microscopy (STEM). Surface regions (~2 nm) of the cycled LiNi0.5Mn1.5O4sub> particles show migration of TM ions into tetrahedral Li sites to form a Mn3O4sub>-like structure. However, subsurface regions of the cycled particles exhibit migration of TM ions into empty octahedral sites to form a rocksalt-like structure. The migration of these TM ions are closely related to dissolution of Ni/Mn ions and building-up of charge transfer impedance, which contribute significantly to the capacity degradation and the poor first-cycle Coulombic efficiency of spinel LiNi0.5Mn1.5O4sub> cathode material. Accordingly, we provide suggestions of effective stabilization of LiNi0.5

  7. Beyond Yolk–Shell Nanoparticles: Fe 3 O 4sub> @Fe 3 C Core@Shell Nanoparticles as Yolks and Carbon Nanospindles as Shells for Efficient Lithium Ion Storage

    SciTech Connect

    Zhang, Jianan; Wang, Kaixi; Xu, Qun; Zhou, Yunchun; Cheng, Fangyi; Guo, Shaojun

    2015-02-25

    In order to well address the problems of large volume change and dissolution of Fe3O4sub> nanomaterials during Li+ intercalation/extraction, herein we demonstrate a one-step in situ nanospace-confined pyrolysis strategy for robust yolk–shell nanospindles with very sufficient internal void space (VSIVS) for high-rate and long-term lithium ion batteries (LIBs), in which an Fe3O4sub>@Fe3C core@shell nanoparticle is well confined in the compartment of a hollow carbon nanospindle. This structure can not only introduce VSIVS to accommodate volume change of Fe3O4sub> but also afford a dual shell of Fe3C and carbon to restrict Fe3O4sub> dissolution, thus providing dual roles for greatly improving the capacity retention. Consequently, Fe3O4sub>@Fe3C–C yolk–shell nanospindles deliver a high reversible capacity of 1128.3 mAh g–1 at even 500 mA g–1, excellent high rate capacity (604.8 mAh g–1 at 2000 mA g1), and prolonged cycling life (maintaining 1120.2 mAh g–1 at 500 mA g–1 for 100 cycles) for LIBs, which are much better than those of Fe3O4sub>@C core@shell nanospindles and Fe3O4sub> nanoparticles. The present Fe3O4sub>@Fe3C–C yolk–shell nanospindles are the most efficient Fe3O4sub>-based anode materials ever reported for LIBs.

  8. High-pressure behavior of cuprospinel CuFe2O4sub>: Influence of the Jahn-Teller effect on the spinel structure

    SciTech Connect

    Kyono, Atsushi; Gramsch, Stephen A.; Nakamoto, Yuki; Sakata, Masafumi; Kato, Masato; Tamura, Tomoya; Yamanaka, Takamitsu

    2015-08-14

    The Jahn-Teller-effect at Cu2+ in cuprospinel CuFe2O4sub> was investigated using high-pressure, single crystal synchrotron x-ray diffraction (XRD) techniques at beamline BL10A at the Photon Factory, KEK, Japan. Six data sets were collected in the pressure range from ambient to 5.9 GPa at room temperature. Structural refinements based on the data were performed at 0.0, 1.8, 2.7, and 4.6 GPa. The unit cell volume of cuprospinel decreases continuously from 590.8 (6) Å3 to 579.5 (8) Å3 up to 3.8 GPa. Leastsquares fitting to a third-order Birch-Murnaghan equation of state yields zero-pressure volume V0 = 590.7 (1) Å3 and bulk modulus K0 = 188.1 (4.4) GPa with K’ fixed at 4.0. The crystal chemical composition determined by electron-probe analysis and x-ray site-occupancy refinement is represented as [Cu0.526Fe0.474][6][Cu0.074Fe1.926]O4sub>. Most of the Cu2+ are preferentially distributed onto the tetrahedral (T) site of the spinel structure. At 4.6 GPa, a cubic-tetragonal phase transition is indicated by a splitting of the a axis of the cubic structure into a smaller a axis and a longer c axis, with unit cell parameters a = 5.882 (1) Å and c = 8.337 (1) Å. The tetragonal crystal structure with space group I4<sub>1/amd was refined to R1 = 0.0182 and wR2 = 0.0134 using observed 35 x-ray reflections. At the T site, the tetrahedral O-T-O bond angles along the c-axis direction of the unit cell decreases slightly from 109.47 ° to 108.7 (4) °, which generates a stretched tetrahedral geometry along the c-axis. The cubic-totetragonal transition induced by the Jahn-Teller effect at Cu2+ is attributable to the angular distortion at the tetrahedral site. At the octahedral (M) site, on the other hand, the two M-O bonds parallel to the caxis are shortened with respect to the four M-O bonds parallel to

  9. Fabrication and electrical properties of Si-based La{sub 10−x}Bi{sub x}(SiO{sub 4}){sub 6}O{sub 3} apatite ionic conductor

    SciTech Connect

    Kim, Dae-Young; Lee, Sung-Gap

    2012-10-15

    In this paper we report an investigation about the relationship between Bi content and conductivity for the La{sub 10−x}Bi{sub x}(SiO{sub 4}){sub 6}O{sub 3} (x = 0.5–2) specimens. Increasing Bi content in apatite-type La{sub 10−x}Bi{sub x}(SiO{sub 4}){sub 6}O{sub 3} specimen leads to increasing the average grain size and sinterability because some Bi ion deposited at grain boundaries which promotes grain growth. The relative sintered density of the La{sub 8}Bi{sub 2}(SiO{sub 4}){sub 6}O{sub 3} specimen is 98%. There is a small shift in diffraction angle of XRD peaks, complicated lattice distortion was observed in the X-ray pattern with increasing content of Bi. Electrical conductivity of La{sub 10−x}Bi{sub x}(SiO{sub 4}){sub 6}O{sub 3} specimen increased with increasing Bi contents and the value of the La{sub 8}Bi{sub 2}(SiO{sub 4}){sub 6}O{sub 3} specimen is 2.4 × 10{sup −4} S cm{sup −1} at 700 °C.

  10. Crystal structure and thermal expansion of the low- and high-temperature forms of BaM{sup IV}(PO{sub 4}){sub 2} compounds (M=Ti, Zr, Hf and Sn)

    SciTech Connect

    Bregiroux, D.; Popa, K.; Jardin, R.; Raison, P.E.; Wallez, G.; Quarton, M.; Brunelli, M.; Ferrero, C.; Caciuffo, R.

    2009-05-15

    The crystal structure of beta-BaZr(PO{sub 4}){sub 2}, archetype of the high-temperature forms of BaM(PO{sub 4}){sub 2} phosphates (with M=Ti, Zr, Hf and Sn), has been solved ab initio by Rietveld analysis from synchrotron X-ray powder diffraction data. The phase transition appears as a topotactic modification of the monoclinic (S.G. C2/m) lamellar alpha-structure into a trigonal one (S.G. P3-barm1) through a simple mechanism involving the unfolding of the [Zr(PO{sub 4}){sub 2}]{sub n}{sup 2-} layers. The thermal expansion is very anisotropic (e.g., -4.14}){sub 2}) and quite different in the two forms, as a consequence of symmetry. It stems from a complex combination of several mechanisms, involving bridging oxygen rocking in M-O-P linkages, and 'bond thermal expansion'. - Graphical abstract: The layered high-temperature form of BaM(PO{sub 4}){sub 2}, only expands along the c-axis.

  11. Temperature-dependent framework–template interaction of |Na{sub 6}(H{sub 2}O){sub 8}|[ZnPO{sub 4}]{sub 6} sodalite

    SciTech Connect

    Robben, Lars Gesing, Thorsten M.

    2013-11-15

    The partial dehydration followed by the decomposition of sodium-zincophosphate-hydrosodalite caused by the total water loss was examined by temperature-dependent X-ray powder diffraction, Fourier transform infrared (FTIR) and Raman spectroscopy as well as thermogravimetry combined with difference thermoanalysis. The dehydration causing the decomposition of this sodalite could be described in a two step-process. Initially two water molecules per unit-cell were lost, changing the interaction between the zincophosphate framework and the remaining water molecules as well as sodium cations as non-framework constituents. In this stage a 3+3 coordination of water molecules and sodium cations in the sodalite cage is observed. Using the autocorrelation function (AC) for the evaluation of the temperature-dependent FTIR spectra of sodalites is reported here for the first time. Calculating the changes in the AC broadness, structural features could well be analyzed due to its correlation with respective structural parameters. Temperature dependent Raman data was used to give a band assignment of bands at Raman shifts below 300 cm{sup −1}. - Graphical abstract: The thermal decomposition of |Na{sub 6}(H{sub 2}O){sub 8}|[ZnPO{sub 4}]{sub 6} sodalite is a two-step process with an initial loss of two water molecules at 400 K, intermediately stabilizing the highly stressed framework. Further heating leads to a subsequent loss of the remaining six water molecules and a breakup of the sodalite framework. A beryllonite-type NaZnPO{sub 4} is the final product of this process. Display Omitted - Highlights: • The decomposition of |Na{sub 6}(H{sub 2}O){sub 8}|[ZnPO{sub 4}]{sub 6} sodalite is a two-step process. • Initial loss of two water molecule at 400 K stabilizes the sodalite (step 1). • Further heating leads to complete loss of water and structural breakdown. • Autocorrelation of temperature dependent FTIR-spectra gives structural information.

  12. Temperature induced phase transition of CaMn{sub 0.5}Zr{sub 1.5}(PO{sub 4}){sub 3} phosphate

    SciTech Connect

    Orlova, Maria; Perfler, Lukas; Tribus, Martina; Salnikov, Petr; Glorieux, Benoit; Orlova, Albina

    2016-03-15

    In this work we investigated the structural behaviour of a CaMn{sub 0.5}Zr{sub 1.5}(PO{sub 4}){sub 3}. Due to the presence of divalent Mn{sup 2+} cations this compound can possess interesting luminescence properties. It was recently understood that this phosphate undergoes a temperature induced irreversible phase transition in the range of 800–875 °C. It has also been shown that the 3d–3d luminescence of Mn{sup 2+} increases 10 fold for the high temperature polymorph. To determine the Mn environment structural investigations of both phases have been performed by the X-ray powder diffraction and Raman spectroscopy methods. The low temperature modification adopts the trigonal NZP structure type with a slightly lower symmetry (space group R32, a=8.7850(2) Å, c=22.6496(7) Å, V=1514.8(1) Å{sup 3}). The high temperature form in turn has orthorhombic symmetry (space group Pnma, a=6.2350(3) Å, b=6.6281(3) Å, c=14.4731(6) Å, V=598.13(5) Å{sup 3}). Both structures were solved ab-initio from powder data and structural analysis was performed. In-situ and RT Raman spectra are consistent with the XRD derived structural model. Mn{sup 2+} cations occupy different types of positions in these structures and a change in Mn coordination number (6 for LT phase, 7 for HT phase) results in different Mn–O bond lengths. These differences may explain the change in the optical properties between the polymorphs. - Graphical abstract: The compound CaMn{sub 0.5}Zr{sub 1.5}(PO{sub 4}){sub 3} was synthesized in order to create a material with enhanced luminescent properties. The goal of present studies is to define Mn{sup 2+} environment and its changes due to the structural transformations of the phosphate along phase transition at the T range of 800–875 °C. It was found that LT modification adopts the trigonal NZP structure type, sp.gr. R32, the HT form in turn exhibits orthorhombic symmetry sp.gr. Pnma. Mn2+ cations occupy different types of positions in those structures and a

  13. Ultra-short-period W/B4sub>C multilayers for x-ray optics-microstructure limits on reflectivity

    SciTech Connect

    Walton, Christopher Charles

    1997-12-01

    Multilayer thin films are used as Bragg reflectors for soft x-rays in the energy range 50eV < E < 1000eV in many x-ray optics applications such as x-ray microscopes and telescopes, reducing optics for extreme ultraviolet (EUV) lithography, and x-ray polarizers and phase retarders. Applications often depend critically on reflectivity, which has not been systematically characterized for multilayer periods below 20Å. For this study, W/B4sub>C multilayers were fabricated by magnetron sputtering on Si(111), with periods from 48Å to as little as 4.7Å. The x-ray reflectivity measured at λ = 1.54Å and at 45° incidence (289 eV < E < 860 eV) was found to decrease sharply for multilayer periods less than 15-20Å. Examination by high-resolution transmission electron microscopy (HRTEM) showed an expansion of the thickness of the W-rich layers of 30-40% from the nominal values, consistent with intermixture of the two materials during sputter growth, and discontinuous W-rich layers for multilayer periods below about 15Å. The experimental data for the specular reflectivity in the hard and soft x-ray regimes and the diffuse scattering fit well to a model of multilayer roughness. The model is expressed as a power-law dependence of roughness on spatial frequency. Analysis of small-angle scattering in transmission from multilayers grown on freestanding Si3N4sub> membranes confirms the onset of discontinuity at periods between 14Å and 22Å. Spectroscopy studies by x-ray absorption (NEXAFS) and electron energy loss (EELS) at the boron K-edge (188eV) are consistent with changes in the average boron bonding environment, as the multilayer period decreases and the W-rich layers are increasingly thin and dispersed. A discrete W-rich phase is present for periods at least as small as 6.3Å.

  14. Low-temperature synthesis of homogeneous solid solutions of scheelite-structured Ca1-xSrxWO4sub> and Sr1-xBaxWO4sub> nanocrystals

    SciTech Connect

    Culver, Sean P.; Greaney, Matthew J.; Tinoco, Antonio; Brutchey, Richard L.

    2015-07-24

    Here, a series of compositionally complex scheelite-structured nanocrystals of the formula A1-xA’xWO4sub> (A = Ca, Sr, Ba) have been prepared under benign synthesis conditions using the vapor diffusion sol–gel method. Discrete nanocrystals with sub-20 nm mean diameters were obtained after kinetically controlled hydro- lysis and polycondensation at room temperature, followed by composition-dependent thermal aging at or below 60 °C. Rietveld analysis of X-ray diffraction data and Raman spectroscopy verified the synthesis of continuous and phase-pure nanocrystal solid solutions across the entire composition space for A1-xA’xWO4sub>, where 0 ≤ x ≤ 1. Elemental analysis by X-ray photoelectron and inductively coupled plasma- atomic emission spectroscopies demonstrated excellent agreement between the nominal and experi- mentally determined elemental stoichiometries, while energy dispersive X-ray spectroscopy illustrated good spatial elemental homogeneity within these nanocrystals synthesized under benign conditions.

  15. Multiband electronic transport in α-Yb1₋xSrx AlB4sub> [ x = 0, 0.19(3)] single crystals

    SciTech Connect

    Ryu, Hyejin; Abeykoon, Milinda; Bozin, Emil; Matsumoto, Yosuke; Nakatsuji, S.; Petrovic, C.

    2016-08-19

    Here we report on the evidence for the multiband electronic transport in α- YbAlB4sub> and α-Yb0.81(2)Sr0.19(3)AlB4sub>. Multiband transport reveals itself below 10 K in both compounds via Hall effect measurements, whereas anisotropic magnetic ground state sets in below 3 K in α-Yb0.81(2)Sr0.19(3)AlB4sub>. Our results show that Sr2+ substitution enhances conductivity, but does not change the quasiparticle mass of bands induced by heavy fermion hybridization.

  16. Spectroscopy and Luminescence Dynamics of Ce 3+ and Sm 3+ in LiYSiO 4sub>

    SciTech Connect

    Shi, Rui; Xu, Jinzhong; Liu, Guokui; Zhang, Xuejie; Zhou, Weihie; Pan, Fengjuan; Huang, Yan; Tao, Ye; Liang, Hongbin

    2016-02-17

    The lithium yttrium silicate series of LiY1-xLnxSiO4sub> exhibits superb chemical and optical properties, and with Ln = Ce3+, Sm3+, its spectroscopic characteristics and luminescence dynamics are investigated in the present work. Energy transfer and non-radiative relaxation dramatically influence the Ln3+ luminescence spectra and decay dynamics, especially in the Ce3+-Sm3+ co-doped phosphors. It is shown that thermal-quenching of the blue Ce3+ luminescence is primarily due to thermal ionization in the 5d excited states rather than multi-phonon relaxation, whereas cross-relaxation arising from electric dipole-dipole interaction between adjacent Sm3+ ions is the leading mechanism that quenches the red Sm3+ luminescence. In the co-doped systems, Ce3+-Sm3+ energy transfer in competing with the thermal quenching enhance the emission from Sm3+. The combined influences of concentration quenching, thermal ionization, energy transfer including cross-relaxation on the luminescence intensity of single-center and co-doped phosphors are analyzed based on the theories of ion-ion and ion-lattice interactions.

  17. Nitridated Pd/B4sub>C multilayer mirrors for soft X-ray region: internal structure and aging effects.

    PubMed

    Wang, Yiwen; Huang, Qiushi; Yi, Qiang; Kozhevnikov, Igor V; Qi, Runze; Wen, Mingwu; Jonnard, Philippe; Zhang, Jinshuai; Giglia, Angelo; Zhang, Zhong; Wang, Zhanshan

    2017-04-03

    Reactive sputtering with a mixture of argon and nitrogen (N2 partial pressure of 4%, 8%, and 15%) as the working gas is used to develop the high reflectance Pd/B4sub>C multilayers for soft X-ray region application. Compared to the pure Ar fabricated sample, the interface roughness of the nitridated multilayer is slightly increased while the compressive stress is essentially relaxed from -623 MPa (pure Ar) to -85 MPa (15% N2). A maximum reflectance of 32% is measured at the wavelength of 9.5 nm for the multilayer fabricated with 15% N2. After storing the multilayers in an air environment for 6-17 months, a distinct aging effect is observed on the nitridated samples. The transmission electron microscopy results indicate that a large part of the top layers of the nitridated samples is deteriorated with severe interdiffusion, essential decrease in d-spacing, and compacted multilayer structure. The deterioration is less pronounced for the multilayers fabricated with a higher ratio of N2. Energy dispersive X-ray spectroscopy reveals that the concentration of nitrogen and boron in the degraded area is much reduced compared to the intact layers. A primitive model of upward diffusion of nitrogen and boron is proposed to explain the aging effects of the nitridated structure.

  18. Ultrafast energy- and momentum-resolved dynamics of magnetic correlations in the photo-doped Mott insulator Sr2IrO4sub>

    SciTech Connect

    Dean, M. P. M.; Cao, Y.; Liu, X.; Wall, S.; Zhu, D.; Mankowsky, R.; Thampy, V.; Chen, X. M.; Vale, J. G.; Casa, D.; Kim, Jungho; Said, A. H.; Juhas, P.; Alonso-Mori, R.; Glownia, J. M.; Robert, A.; Robinson, J.; Sikorski, M.; Song, S.; Kozina, M.; Lemke, H.; Patthey, L.; Owada, S.; Katayama, T.; Yabashi, M.; Tanaka, Yoshikazu; Togashi, T.; Liu, J.; Rayan Serrao, C.; Kim, B. J.; Huber, L.; Chang, C. -L.; McMorrow, D. F.; Forst, M.; Hill, J. P.

    2016-05-09

    Measuring how the magnetic correlations evolve in doped Mott insulators has greatly improved our understanding of the pseudogap, non-Fermi liquids and high-temperature superconductivity1, 2, 3, 4. Recently, photo-excitation has been used to induce similarly exotic states transiently5, 6, 7. However, the lack of available probes of magnetic correlations in the time domain hinders our understanding of these photo-induced states and how they could be controlled. Here, we implement magnetic resonant inelastic X-ray scattering at a free-electron laser to directly determine the magnetic dynamics after photo-doping the Mott insulator Sr2IrO4sub>. We find that the non-equilibrium state, 2 ps after the excitation, exhibits strongly suppressed long-range magnetic order, but hosts photo-carriers that induce strong, non-thermal magnetic correlations. These two-dimensional (2D) in-plane Néel correlations recover within a few picoseconds, whereas the three-dimensional (3D) long-range magnetic order restores on a fluence-dependent timescale of a few hundred picoseconds. In conclusion, the marked difference in these two timescales implies that the dimensionality of magnetic correlations is vital for our understanding of ultrafast magnetic dynamics.

  19. Stable platinum nanoparticles on specific MgAl2O4sub> spinel facets at high temperatures in oxidizing atmospheres

    SciTech Connect

    Li, Wei-Zhen; Kovarik, Libor; Mei, Donghai; Liu, Jun; Wang, Yong; Peden, Charles H. F.

    2013-09-25

    The development of thermally stable, nanometer-sized precious metal-based catalysts remains a daunting challenge. Such materials, especially those based on the use of costly platinum metal, are essential and, to date, non-replaceable for a large number of industrially important catalytic processes. Here we report a well-defined cuboctahedral MgAl2O4sub> spinel support material that is capable of stabilizing platinum particles in the range of 1–3 nm on its relatively abundant {111} facets during extremely severe aging at 800 °C in air for 1 week. The aged catalysts retain platinum dispersions of 15.9% with catalytic activities for methanol oxidation being ~80% of that of fresh ones, whereas a conventional Pt/γ-Al2O3 catalyst is severely sintered and nearly inactive. Finally, we reveal the origin of the markedly superior ability of spinel {111} facets, resulting from strong interactions between spinel surface oxygens and epitaxial platinum {111} facets, inspiring the rational design of anti-sintering supported platinum group catalysts.

  20. Passive Q-switching of a Tm,Ho:KLu(WO4sub>)2 microchip laser by a Cr:ZnS saturable absorber.

    PubMed

    Serres, J M; Loiko, P; Mateos, X; Jambunathan, V; Yasukevich, A S; Yumashev, K V; Petrov, V; Griebner, U; Aguiló, M; Díaz, F

    2016-05-10

    A diode-pumped Tm,Ho:KLu(WO4sub>)2 microchip laser passively Q-switched with a Cr:ZnS saturable absorber generated an average output power of 131 mW at 2063.6 nm with a slope efficiency of 11% and a Q-switching conversion efficiency of 58%. The pulse characteristics were 14  ns/9  μJ at a pulse repetition frequency of 14.5 kHz. With higher modulation depth of the saturable absorber, 9  ns/10.4  μJ/8.2  kHz pulses were generated at 2061.1 nm, corresponding to a record peak power extracted from a passively Q-switched Tm,Ho laser of 1.15 kW. A theoretical model is presented, predicting the pulse energy and duration. The simulations are in good agreement with the experimental results.

  1. Optical gain in capillary light guides filled with NaYF4sub>: Yb3+, Er3+ nanocolloids.

    PubMed

    Patel, Darayas N; Sarkisov, Sergey S; Darwish, Abdalla M; Ballato, John

    2016-09-05

    A capillary light guide optical amplifier using nanocolloids of Yb3+-Er3+ co-doped NaYF4sub> as a filler was successfully demonstrated. A 7-cm-long and 150-micron-inner-diameter capillary light guide was capable to amplify a pulsed optical signal at 1550 nm with a gain coefficient of 0.15 cm-1 at a pump power of 4 mW (980-nm wavelength). The nanocolloid gain medium was prepared by pulverizing the phosphor powder with a high-speed planetary ball mill. Ball milling of the powder in water produced nanoparticles with a size of approximately 130 nm that after drying were transferred to a liquid with high refractive index (1.551 at 1550 nm) required to maintain light confinement within the fused silica capillary light guide. The results show that RE-doped colloids of nanocrystals can be potentially used as liquid gain media fillers in capillary light guide lasers and amplifiers with high photostability and low toxicity.

  2. Dynamic tensile deformation and damage of B4sub>C-reinforced Al composites: Time-resolved imaging with synchrotron x-rays

    SciTech Connect

    Bie, B. X.; Huang, J. Y.; Su, B.; Lu, L.; Fan, D.; E, J. C.; Sun, T.; Fezzaa, K.; Qi, M. L.; Luo, S. N.

    2016-03-30

    Dynamic tensile experiments are conducted on 15% and 30% in weight percentage B4sub>C/Al composites with a split Hopkinson tension bar, along with high-speed synchrotron x-ray digital image correlation (XDIC) to map strain fields at μ m and μ s scales. As manifested by bulk-scale stress – strain curves, a higher particle content leads to a higher yield strength but lower ductility. Strain field mapping by XDIC demonstrates that tension deformation and tensile fracture, as opposed to shear and shear failure, dominate deformation and failure of the composites. The fractographs of recovered samples show consistent features. The particle-matrix interfaces are nucleation sites for strain localizations, and their propagation and coalescence are diffused by the Al matrix. The reduced spacing between strain localization sites with increasing particle content, facilitates their coalescence and leads to decreased ductility. Furthermore, designing a particle-reinforced, metallic-matrix composite with balanced strength and ductility should consider optimizing the inter-particle distance as a key par

  3. An air-stable Na3SbS4sub> superionic conductor prepared by a rapid and economic synthetic procedure

    SciTech Connect

    Wang, Hui; Chen, Yan; Hood, Zachary D.; Samuthira Pandian, Amaresh; Keum, Jong Kahk; An, Ke; Sahu, Gayatri; Liang, Chengdu

    2016-01-01

    All-solid-state sodium batteries, using abundant sodium resources and solid electrolyte, hold much promise for safe, low cost, large-scale energy storage. To realize the practical applications of all solid Na-ion batteries at ambient temperature, the solid electrolytes are required to have high ionic conductivity, chemical stability, and ideally, easy preparation. Ceramic electrolytes show higher ionic conductivity than polymers, but they often require extremely stringent synthesis conditions, either high sintering temperature above 1000 C or long-time, low-energy ball milling. Herein, we report a new synthesis route for Na3SbS4sub>, a novel Na superionic conductor that needs much lower processing temperature below 200 C and easy operation. This new solid electrolyte exhibits a remarkable ionic conductivity of 1.05 mS cm-1 at 25 °C and is chemically stable under ambient atmosphere. In conclusion, this synthesis process provides unique insight into the current state-of-the-art solid electrolyte preparation and opens new possibilities for the design of similar materials.

  4. Pressure effects on magnetic ground states in cobalt doped multiferroic Mn1-xCoxWO4sub>

    SciTech Connect

    Wang, Jinchen; Ye, Feng; Chi, Songxue; Fernandez-Baca, Jaime A.; Cao, Huibo; Tian, Wei; Gooch, Mellisa; Poudel, N.; Wang, Yaqi Q.; Lorenz, Bernd; Chu, C. W.

    2016-04-28

    Using x-ray and high pressure neutron diffraction, we studied the pressure effect on structural and magnetic properties of multiferroic Mn1-xCoxWO4sub> single crystals (x = 0, 0.05, 0.135 and 0.17), and compared it with the effects of doping. Both Co doping and pressure stretch the Mn-Mn chain along the c direction. At high doping level (x = 0.135 and 0.17), pressure and Co doping drive the system in a very similar way and induce a spin-flop transition for the x = 0.135 compound. In contrast, magnetic ground states at lower doping level (x = 0 and 0.05) are robust against pressure but experience a pronounced change upon Co substitution. As Co introduces both chemical pressure and magnetic anisotropy into the frustrated magnetic system, our results suggest the magnetic anisotropy is the main driving force for the Co induced phase transitions at low doping level, and chemical pressure plays a more significant role at higher Co concentrations.

  5. One-dimensional lone electron pair micelles in the crystal structure of Pb{sub 5}(SiO{sub 4})(VO{sub 4}){sub 2}

    SciTech Connect

    Krivovichev, S.V.; Armbruster, T.; Depmeier, W

    2004-09-01

    The structure of Pb{sub 5}(SiO{sub 4})(VO{sub 4}){sub 2} (hexagonal, P6{sub 3}/m, a = 9.9865(11), c = 7.3599(12) A, V = 635.67(14) A{sup 3}, Z = 2) has been solved by direct methods and refined to R{sub 1} = 0.051 on the basis of 440 unique observed reflections with vertical bar F{sub o} vertical bar{>=}4{sigma}{sub F}. The compound belongs to the apatite structure type. The Pb coordination polyhedra are distorted due to the presence of stereoactive lone electron pairs {psi}. The structure contains channels running along the c axis and centered at (00z). The channels are most probably occupied by the lone electron pairs of the Pb{sup 2+} cations and thus represent lone electron pair micelles. The existence of such micelles in the structure may well be the reason for the electrogyratory effect and protonic conductivity observed in crystals of the title compound.

  6. X-ray absorption spectroscopy of LiBF 4sub> in propylene carbonate. A model lithium ion battery electrolyte

    SciTech Connect

    Smith, Jacob W.; Lam, Royce K.; Sheardy, Alex T.; Shih, Orion; Rizzuto, Anthony M.; Borodin, Oleg; Harris, Stephen J.; Prendergast, David; Saykally, Richard J.

    2014-08-20

    Since their introduction into the commercial marketplace in 1991, lithium ion batteries have become increasingly ubiquitous in portable technology. Nevertheless, improvements to existing battery technology are necessary to expand their utility for larger-scale applications, such as electric vehicles. Advances may be realized from improvements to the liquid electrolyte; however, current understanding of the liquid structure and properties remains incomplete. X-ray absorption spectroscopy of solutions of LiBF4sub> in propylene carbonate (PC), interpreted using first-principles electronic structure calculations within the eXcited electron and Core Hole (XCH) approximation, yields new insight into the solvation structure of the Li+ ion in this model electrolyte. By generating linear combinations of the computed spectra of Li+-associating and free PC molecules and comparing to the experimental spectrum, we find a Li+–solvent interaction number of 4.5. This result suggests that computational models of lithium ion battery electrolytes should move beyond tetrahedral coordination structures.

  7. Quantum Monte Carlo analysis of a charge ordered insulating antiferromagnet: the Ti4sub>O7 Magnéli phase

    SciTech Connect

    Benali, Anouar; Shulenburger, Luke; Krogel, Jaron T.; Zhong, Xiaoliang; Kent, Paul R. C.; Heinonen, Olle

    2016-06-07

    The Magnéli phase Ti4sub>O7 is an important transition metal oxide with a wide range of applications because of its interplay between charge, spin, and lattice degrees of freedom. At low temperatures, it has non-trivial magnetic states very close in energy, driven by electronic exchange and correlation interactions. In this paper, we have examined three low-lying states, one ferromagnetic and two antiferromagnetic, and calculated their energies as well as Ti spin moment distributions using highly accurate quantum Monte Carlo methods. We compare our results to those obtained from density functional theory-based methods that include approximate corrections for exchange and correlation. Our results confirm the nature of the states and their ordering in energy, as compared with density-functional theory methods. However, the energy differences and spin distributions differ. Finally, a detailed analysis suggests that non-local exchange–correlation functionals, in addition to other approximations such as LDA+U to account for correlations, are needed to simultaneously obtain better estimates for spin moments, distributions, energy differences and energy gaps.

  8. Quantum Monte Carlo analysis of a charge ordered insulating antiferromagnet: The Ti4sub>O7 Magneli phase

    SciTech Connect

    Benali, Anouar; Shulenburger, Luke; Krogel, Jaron T.; Zhong, Xiaoling; Kent, Paul R. C.; Heinonen, Olle

    2016-06-07

    The Magneli phase Ti4sub>O7 is an important transition metal oxide with a wide range of applications because of its interplay between charge, spin, and lattice degrees of freedom. At low temperatures, it has non-trivial magnetic states very close in energy, driven by electronic exchange and correlation interactions. We have examined three low- lying states, one ferromagnetic and two antiferromagnetic, and calculated their energies as well as Ti spin moment distributions using highly accurate Quantum Monte Carlo methods. We compare our results to those obtained from density functional theory- based methods that include approximate corrections for exchange and correlation. Our results confirm the nature of the states and their ordering in energy, as compared with density-functional theory methods. However, the energy differences and spin distributions differ. Here, a detailed analysis suggests that non-local exchange-correlation functionals, in addition to other approximations such as LDA+U to account for correlations, are needed to simultaneously obtain better estimates for spin moments, distributions, energy differences and energy gaps.

  9. Structural transition and orbital glass physics in near-itinerant CoV2O4sub>

    SciTech Connect

    Reig-i-Plessis, D.; Casavant, D.; Garlea, Vasile O.; Aczel, Adam A.; Feygenson, Mikhail; Neuefeind, Joerg C.; Zhou, H. D.; Nagler, Stephen E.; MacDougall, Gregory J.

    2016-01-25

    In this study, the ferrimagnetic spinel CoV2O4sub> has been a topic of intense recent interest, both as a frustrated insulator with unquenched orbital degeneracy and as a near-itinerant magnet which can be driven metallic with moderate applied pressure. Here, we report on our recent neutron di raction and inelastic scattering measurements on powders with minimal cation site disorder. Our main new result is the identification of a weak (Δa/a ~ 10–4), first order structural phase transition at T* = 90 K, the same temperature where spin canting was seen in recent single crystal measurements. This transition is characterized by a short-range distortion of oxygen octahedral positions, and inelastic data further establish a weak 1.25meV spin gap at low temperature. Together, these findings provide strong support for the local orbital picture and the existence of an orbital glass state at temperatures below T*.

  10. Synthesis of nanostructured LiTi{sub 2}(PO{sub 4}){sub 3} powder by a Pechini-type polymerizable complex method

    SciTech Connect

    Mariappan, C.R.; Galven, C.; Crosnier-Lopez, M.-P.; Le Berre, F.; Bohnke, O. . E-mail: odile.bohnke@univ-lemans.fr

    2006-02-15

    The nanostructured NASICON-type LiTi{sub 2}(PO{sub 4}){sub 3} (LTP) material has been synthesized by Pechini-type polymerizable complex method. The use of water-soluble ammonium citratoperoxotitanate (IV) metal complex instead of alkoxides as precursor allows to prepare monophase material. Thermal analyses have been carried out on the powder precursor to check the weight loss and synthesis temperature. X-ray powder diffraction analysis (XRD) has been performed on the LTP powder obtained after heating the powder precursor over a temperature range from 550 to 1050 deg. C for 2 h. By varying the molar ratio of citric acid to metal ion (CA/Ti) and citric acid to ethylene glycol (CA/EG), the grain size of the LTP powder could be modified. The formation of small and well-crystalline grains, in the order of 50-125 nm in size, has been determined from the XRD patterns and confirmed by transmission electron microscopy.

  11. Cation ratio fluctuations in Cu2ZnSnS4sub> at the 20 nm length scale investigated by analytical electron microscopy

    SciTech Connect

    Aguiar, Jeffery A.; Erkan, Mehmet E.; Pruzan, Dennis S.; Nagaoka, Akira; Yoshino, Kenji; Moutinho, Helio; Al-Jassim, Mowafak; Scarpulla, Michael A.

    2016-04-05

    Kesterite Cu2ZnSn(S,Se)4sub> (CZTSSe) is a sustainable material for thin-film photovoltaics with device efficiencies greater than 12% have been demonstrated. Despite similar crystal structure and polycrystalline film microstructures, there is widespread evidence for larger-amplitude potential and bandgap fluctuations in CZTS than in the analogous Cu(In,Ga)Se2 (CIGSe) chalcopyrite material. This disorder is believed to account for a sizable part of the larger open-circuit voltage (VOC) deficit in CZTS devices, yet the detailed origins and length scales of these fluctuations have not been fully elucidated. Herein, we present a transmission electron microscopy study focusing on composition variation within bulk multicrystals of CZTS grown by the travelling heater method (THM). In these slow-cooled, solution grown crystals we find direct evidence for spatial composition fluctuations of amplitude <1 at.% (~5 x 1020 cm-3) and thus, explainable by point defects. However, rather than being homogeneously-distributed we find a characteristic 20 nm length scale for these fluctuations, which sets a definite length scale for band gap and potential fluctuations. At Σ3 grain boundaries, we find no evidence of composition variation compared to the bulk. The finding highlights such variations reported at grain boundaries in polycrystalline thin-films are direct consequences of processing methods and not intrinsic properties of CZTS itself.

  12. New localized/delocalized emitting state of Eu2+ in orange-emitting hexagonal EuAl2O4sub>

    SciTech Connect

    Liu, Feng; Meltzer, Richard S.; Li, Xufan; Budai, John D.; Chen, Yu -Sheng; Pan, Zhengwei

    2014-11-18

    Eu2+-activated phosphors are being widely used in illuminations and displays. Some of these phosphors feature an extremely broad and red-shifted Eu2+ emission band; however, convincing explanation of this phenomenon is lacking. Here we report a new localized/delocalized emitting state of Eu2+ ions in a new hexagonal EuAl2O4sub> phosphor whose Eu2+ luminescence exhibits a very large bandwidth and an extremely large Stokes shift. At 77 K, two luminescent sites responsible for 550 nm and 645 nm broadband emissions are recognized, while at room temperature only the 645 nm emission band emits. The 645 nm emission exhibits a typical radiative lifetime of 1.27 μs and an unusually large Stokes shift of 0.92 eV. We identify the 645 nm emission as originating from a new type of emitting state whose composition is predominantly that of localized 4f65d character but which also contains a complementary component with delocalized conduction-band-like character. This investigation gives new insights into a unique type of Eu2+ luminescence in solids whose emission exhibits both a very large bandwidth and an extremely large Stokes shift.

  13. Band alignment of atomic layer deposited (HfZrO{sub 4}){sub 1−x}(SiO{sub 2}){sub x} gate dielectrics on Si (100)

    SciTech Connect

    Heo, Sung; Tahir, Dahlang; Chung, Jae Gwan; Lee, Jae Cheol; Kim, KiHong; Lee, Junho; Lee, Hyung-Ik; Park, Gyeong Su; Oh, Suhk Kun; Kang, Hee Jae; Choi, Pyungho; Choi, Byoung-Deog

    2015-11-02

    The band alignment of atomic layer deposited (HfZrO{sub 4}){sub 1−x}(SiO{sub 2}){sub x} (x = 0, 0.10, 0.15, and 0.20) gate dielectric thin films grown on Si (100) was obtained by using X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. The band gap, valence band offset, and conduction band offset values for HfZrO{sub 4} silicate increased from 5.4 eV to 5.8 eV, from 2.5 eV to 2.75 eV, and from 1.78 eV to 1.93 eV, respectively, as the mole fraction (x) of SiO{sub 2} increased from 0.1 to 0.2. This increase in the conduction band and valence band offsets, as a function of increasing SiO{sub 2} mole fraction, decreased the gate leakage current density. As a result, HfZrO{sub 4} silicate thin films were found to be better for advanced gate stack applications because they had adequate band gaps to ensure sufficient conduction band offsets and valence band offsets to Si.

  14. Anisotropic lattice thermal expansion of PbFeBO4sub>: A study by X-ray and neutron diffraction, Raman spectroscopy and DFT calculations

    SciTech Connect

    Murshed, M. Mangir; Mendive, Cecilia B.; Curti, Mariano; Nénert, Gwilherm; Kalita, Patricia E.; Lipinska, Kris; Cornelius, Andrew L.; Huq, Ashfia; Gesing, Thorsten M.

    2014-11-01

    We present the lattice thermal expansion of mullite-type PbFeBO4sub> in this study. The thermal expansion coefficients of the metric parameters were obtained from composite data collected from temperature-dependent neutron and X-ray powder diffraction between 10 K and 700 K. The volume thermal expansion was modeled using extended Grüneisen first-order approximation to the zero-pressure equation of state. The additive frame of the model includes harmonic, quasi-harmonic and intrinsic anharmonic potentials to describe the change of the internal energy as a function of temperature. Moreover, the unit-cell volume at zero-pressure and 0 K was optimized during the DFT simulations. Harmonic frequencies of the optical Raman modes at the Γ-point of the Brillouin zone at 0 K were also calculated by DFT, which help to assign and crosscheck the experimental frequencies. The low-temperature Raman spectra showed significant anomaly in the antiferromagnetic regions, leading to softening or hardening of some phonons. Selected modes were analyzed using a modified Klemens model. The shift of the frequencies and the broadening of the line-widths helped to understand the anharmonic vibrational behaviors of the PbO4, FeO6 and BO3 polyhedra as a function of temperature.

  15. Quantitation of Free Radicals in B6C3F1 Mouse Liver Slices on Exposure to Four Chemical Carcinogens: An EPR-Spin Trapping Study

    DTIC Science & Technology

    1996-03-01

    AL/OE-TR-1996-0083 UNITED STATES AIR FORCE ARMSTRONG LABORATORY QUANTITÄTEN OF FREE RADICALS IN B6C3F1 MOUSE LIVER SLICES ON EXPOSURE TO FOUR...AFB, OH 45433 Janusz Byczkowski MANTECH GEO-CENTERS JOINTVENTURE P.O. BOX 31009 DAYTON, OH 45437 Alasdair Carmichael ARMED FORCES RADIOBIOLOGY...request copies of this report from the Air Force Armstrong Laboratory. Additional copies may be purchased from: National Technical Information Service

  16. Small 6q16.1 Deletions Encompassing POU3F2 Cause Susceptibility to Obesity and Variable Developmental Delay with Intellectual Disability

    PubMed Central

    Kasher, Paul R.; Schertz, Katherine E.; Thomas, Megan; Jackson, Adam; Annunziata, Silvia; Ballesta-Martinez, María J.; Campeau, Philippe M.; Clayton, Peter E.; Eaton, Jennifer L.; Granata, Tiziana; Guillén-Navarro, Encarna; Hernando, Cristina; Laverriere, Caroline E.; Liedén, Agne; Villa-Marcos, Olaya; McEntagart, Meriel; Nordgren, Ann; Pantaleoni, Chiara; Pebrel-Richard, Céline; Sarret, Catherine; Sciacca, Francesca L.; Wright, Ronnie; Kerr, Bronwyn; Glasgow, Eric; Banka, Siddharth

    2016-01-01

    Genetic studies of intellectual disability and identification of monogenic causes of obesity in humans have made immense contribution toward the understanding of the brain and control of body mass. The leptin > melanocortin > SIM1 pathway is dysregulated in multiple monogenic human obesity syndromes but its downstream targets are still unknown. In ten individuals from six families, with overlapping 6q16.1 deletions, we describe a disorder of variable developmental delay, intellectual disability, and susceptibility to obesity and hyperphagia. The 6q16.1 deletions segregated with the phenotype in multiplex families and were shown to be de novo in four families, and there was dramatic phenotypic overlap among affected individuals who were independently ascertained without bias from clinical features. Analysis of the deletions revealed a ∼350 kb critical region on chromosome 6q16.1 that encompasses a gene for proneuronal transcription factor POU3F2, which is important for hypothalamic development and function. Using morpholino and mutant zebrafish models, we show that POU3F2 lies downstream of SIM1 and controls oxytocin expression in the hypothalamic neuroendocrine preoptic area. We show that this finding is consistent with the expression patterns of POU3F2 and related genes in the human brain. Our work helps to further delineate the neuro-endocrine control of energy balance/body mass and demonstrates that this molecular pathway is conserved across multiple species. PMID:26833329

  17. Small 6q16.1 Deletions Encompassing POU3F2 Cause Susceptibility to Obesity and Variable Developmental Delay with Intellectual Disability.

    PubMed

    Kasher, Paul R; Schertz, Katherine E; Thomas, Megan; Jackson, Adam; Annunziata, Silvia; Ballesta-Martinez, María J; Campeau, Philippe M; Clayton, Peter E; Eaton, Jennifer L; Granata, Tiziana; Guillén-Navarro, Encarna; Hernando, Cristina; Laverriere, Caroline E; Liedén, Agne; Villa-Marcos, Olaya; McEntagart, Meriel; Nordgren, Ann; Pantaleoni, Chiara; Pebrel-Richard, Céline; Sarret, Catherine; Sciacca, Francesca L; Wright, Ronnie; Kerr, Bronwyn; Glasgow, Eric; Banka, Siddharth

    2016-02-04

    Genetic studies of intellectual disability and identification of monogenic causes of obesity in humans have made immense contribution toward the understanding of the brain and control of body mass. The leptin > melanocortin > SIM1 pathway is dysregulated in multiple monogenic human obesity syndromes but its downstream targets are still unknown. In ten individuals from six families, with overlapping 6q16.1 deletions, we describe a disorder of variable developmental delay, intellectual disability, and susceptibility to obesity and hyperphagia. The 6q16.1 deletions segregated with the phenotype in multiplex families and were shown to be de novo in four families, and there was dramatic phenotypic overlap among affected individuals who were independently ascertained without bias from clinical features. Analysis of the deletions revealed a ∼350 kb critical region on chromosome 6q16.1 that encompasses a gene for proneuronal transcription factor POU3F2, which is important for hypothalamic development and function. Using morpholino and mutant zebrafish models, we show that POU3F2 lies downstream of SIM1 and controls oxytocin expression in the hypothalamic neuroendocrine preoptic area. We show that this finding is consistent with the expression patterns of POU3F2 and related genes in the human brain. Our work helps to further delineate the neuro-endocrine control of energy balance/body mass and demonstrates that this molecular pathway is conserved across multiple species.

  18. Tetrel bond of pseudohalide anions with XH3F (X = C, Si, Ge, and Sn) and its role in SN2 reaction.

    PubMed

    Liu, Mingxiu; Li, Qingzhong; Cheng, Jianbo; Li, Wenzuo; Li, Hai-Bei

    2016-12-14

    The complexes of XH3F⋯N3(-)/OCN(-)/SCN(-) (X = C, Si, Ge, and Sn) have been investigated at the MP2/aug-cc-pVTZ(PP) level. The σ-hole of X atom in XH3F acts as a Lewis acid forming a tetrel bond with pseudohalide anions. Interaction energies of these complexes vary from -8 to -50 kcal/mol, mainly depending on the nature of X and pseudohalide anions. Charge transfer from N/O/S lone pair to X-F and X-H σ(*) orbitals results in the stabilization of these complexes, and the former orbital interaction is responsible for the large elongation of X-F bond length and the remarkable red shift of its stretch vibration. The tetrel bond in the complexes of XH3F (X = Si, Ge, and Sn) exhibits a significant degree of covalency with XH3F distorted significantly in these complexes. A breakdown of the individual forces involved attributes the stability of the interaction to mainly electrostatic energy, with a relatively large contribution from polarization. The transition state structures that connect the two minima for CH3Br⋯N3(-) complex have been localized and characterized. The energetic, geometrical, and topological parameters of the complexes were analyzed in the different stages of the SN2 reaction N3(-) + CH3Br → Br(-) + CH3N3.

  19. Evaluation of Manganese Doped Ca5(PO4)3F as a Near Infrared (1-2 microns) Solid-State Laser Material

    NASA Technical Reports Server (NTRS)

    Turner, Matthew; Hoemmerich, Uwe; Loutts, George B.

    1998-01-01

    Tunable solid-state lasers are of enormous interest for applications including fundamental spectroscopy, remote sensing of the earth atmosphere, medical surgery, and optical communications. Efficient and widely tunable lasers have been developed for the 800-1100 nm region based on transition metal doped insulators like e.g. Ti:Sapphire. The development of transition metal lasers operating at longer wavelength, however, has been limited by the luminescence efficiency of existing materials. We are currently evaluating Mn doped Ca5(PO4)3F as a new solid-state laser material for the 1-2 micro-m region. Preliminary spectroscopic studies revealed that Mn:Ca5(PO4)3F exhibits an intense near infrared luminescence which extends from 1100-1300 nm. Based on lifetime measurements we estimated the luminescence quantum efficiency to be as high as 90 deg./0 at room temperature. The near infrared luminescence properties of Mn doped Ca5(PO4)3F and its potential for solid-state laser applications will be discussed in detail.

  20. A theoretical study of thermal decomposition of CF 3CO, C 2F 5CO and C 3F 7CO

    NASA Astrophysics Data System (ADS)

    Setokuchi, Osamu; Kutsuna, Shuzo; Sato, Masaru

    2006-10-01

    Thermal decomposition of C nF 2 n+1 CO ( n = 1-3) radicals was investigated using RRKM/ME calculations, with geometrical parameters and energetics determined at the G2M//MPW1K and CBS-QB3 levels. The decomposition rate constant of C nF 2 n+1 CO increases with increasing carbon chain length. In the atmosphere, decomposition of C 3F 7CO competes with a reaction with O 2 that produces C 3F 7C(O)O 2. The decomposition fraction of C 3F 7CO is calculated to be 73% and 50% at the G2M//MPW1K and CBS-QB3 levels under ambient conditions, whereas that of CF 3CO is 1%. The yields of C nF 2 n+1 C(O)OH, formed by the reaction of C nF 2 n+1 C(O)O 2 with HO 2, are discussed using the obtained results.

  1. Experimental and theoretical methods to study structural phase transition mechanisms in K{sub 3}WO{sub 3}F{sub 3} oxyfluoride

    SciTech Connect

    Krylov, A.S.; Sofronova, S.N.; Kolesnikova, E.M.; Ivanov, Yu.N.; Sukhovsky, A.A.; Goryainov, S.V.; Ivanenko, A.A.; Shestakov, N.P.; Kocharova, A.G.; Vtyurin, A.N.

    2014-10-15

    The results of structural phase transitions mechanisms study in K{sub 3}WO{sub 3}F{sub 3}oxyfluoride are represented by different experimental and theoretical methods. The structural phase transition anomalies at T{sub 1}=452 K and T{sub 2}=414 K of Raman and IR spectra have been analyzed. Using vibrational spectroscopy methods, the NMR-experiment has been done to clarify the nature of found phase transitions: displacive types or order-disorder types. The model of “disordered” crystal was proposed, and the results of lattice dynamics calculation in frameworks of the generalized Gordon–Kim method of ordered (R3) and “disordered” crystals were compared. The high pressure phases were studied by the Raman technique too. - Graphical abstract: (1) Two possible configuration of octahedra. (2). All phases Raman lines of octahedra. (3) All phases IR lines of octahedra. (4) NMR spectra of all phases. - Highlights: • The results of study oxyfluoride K{sub 3}WO{sub 3}F{sub 3} are represented by Raman, IR, NMR technique. • The high pressure phases were studied by the Raman technique. • The anionic octahedra [WO{sub 3}F{sub 3}]{sup 3−} are not ordered below the both phase transitions. • The ferroelectric phase is realized due to the shift of atoms without F/O ordering. • Both of found phase transitions are close to the second order.

  2. Electronic structure of self-doped layered Eu3F4Bi2S4 material revealed by x-ray absorption spectroscopy and photoelectron spectromicroscopy

    NASA Astrophysics Data System (ADS)

    Paris, E.; Sugimoto, T.; Wakita, T.; Barinov, A.; Terashima, K.; Kandyba, V.; Proux, O.; Kajitani, J.; Higashinaka, R.; Matsuda, T. D.; Aoki, Y.; Yokoya, T.; Mizokawa, T.; Saini, N. L.

    2017-01-01

    We have studied the electronic structure of Eu3F4Bi2S4 using a combination of Eu L3-edge x-ray absorption spectroscopy (XAS) and space-resolved angle-resolved photoemission spectroscopy (ARPES). From the Eu L3-edge XAS, we have found that the Eu in this system is in mixed valence state with coexistence of Eu2 +/Eu3 + . The bulk charge doping was estimated to be ˜0.3 per Bi site in Eu3F4Bi2S4 , which corresponds to the nominal x in a typical REO1 -xFxBiS2 system (RE: rare-earth elements). From the space-resolved ARPES, we have ruled out the possibility of any microscale phase separation of Eu valence in the system. Using a microfocused beam we have observed the band structure as well as the Fermi surface that appeared similar to other compounds of this family with disconnected rectangular electronlike pockets around the X point. The Luttinger volume analysis gives the effective carrier to be 0.23 electrons per Bi site in Eu3F4Bi2S4 , indicating that the system is likely to be in the underdoped region of its superconducting phase diagram.

  3. [Intravitreous injection of bevacizumab and C3F8 gas for the treatment of submacular hemorrhage due to age-related macular degeneration: case reports].

    PubMed

    Ferraz, Daniel Araújo; Bressanim, Gláucio Luciano; Morita, Celso; Takahashi, Walter Yukihiko

    2010-01-01

    The purpose of this case series is to describe if the intravitreal use of bevacizumab and perfluoropropane gas (C3F8) would be beneficial to the displacement of subretinal hemorrhage in patients with age-related macular degeneration (AMD). A retrospective study of 5 eyes that received concurrent intravitreal injection of bevacizumab and C3F8 was performed. The results were graded according to blood displacement under the fovea, best final visual acuity and intraoperative complications. At the initial presentation, mean age of patients was 72.6 +/- 8.9 years-old and duration of symptoms was 13 +/- 9.7 days. From the 5 patients, 3 (60%) were male and 2 (40%) female. The success of submacular hemorrhage full displacement was achieved in 4 patients. The mean preoperative visual acuity (VA) was 1.12 +/- 0.34 logMAR and the mean postoperative VA was 0.92 +/- 0.4 logMAR. No cases of retinal detachment, endophthalmitis, vitreous hemorrhage, uveitis, cataracts and increased intraocular pressure were noted during the follow-up period. Intravitreal bevacizumab and C3F8 injection, associated to prone position can be a valuable therapeutic option for eyes with neovascular age-related macular degeneration and subretinal hemorrhage to the blood displacement out of the foveal area.

  4. Fundamental Studies of In Situ Plasma Chamber Cleaning Chemistries: C2F6/O2, C3F8/O2, and NF3/He.

    NASA Astrophysics Data System (ADS)

    Entley, William R.; Hennessy, William J.; Langan, John G.

    1999-10-01

    The plasma etching of SiO2 and Si3N4 in C2F6-O2 and C3F8-O2 mixtures has been studied as a function of feed gas composition (SiO2 substrates), pressure (Si3N4 substrates), and power (SiO2 substrates) in a modified commercial RIE chamber. The chamber has been modified to permit in situ electrical measurements, which allows us to correlate the substrate etch rates and power coupling efficiencies to the discharge impedance. In addition, gas-phase FTIR spectroscopy was used to quantify the PFC emissions for the various gas mixtures investigated. For a fixed rf power, pressure, and total gas flow rate, the maximum etch rate of SiO2 was found to occur within a relatively narrow range of oxygen concentrations, centered near a gas composition of 33 mol observed for a wider range of oxygen concentrations in C2F6 based plasmas. Although the destruction efficiency (the percentage of PFC destroyed in the plasma) of C2F6 and C3F8 in O2 based mixtures are comparable under similar operating conditions, significantly larger quantities of plasma generated CF4 are formed in C3F8-O2 gas mixtures. Comparisons are made to NF3/He discharges, which show higher etch rates and higher destruction efficiencies for appropriately chosen operating conditions.

  5. Collisional quenching reaction rate coefficients of N2 (A3Σu+) by C2F6 and C3F8

    NASA Astrophysics Data System (ADS)

    Suzuki, Susumu; Kuboaki, Masaru; Itoh, Haruo

    2015-09-01

    The collisional quenching reaction rate coefficient of N2 (A3Σu+) by various air pollutant gases were determined from the measurement of the effective lifetime of N2 (A3Σu+) in pure N2 (5-nine) with a small amount of air pollutant gases as an admixture. Derivation of the rate coefficient was performed the waveform analysis of the transient ionization current after turning off the UV light in the Townsend discharge. In this paper, we report that the obtained collisional quenching reaction rate coefficients of N2 (A3Σu+) by C2F6 and C3F8 are (2.3 +/- 1.8) × 10-15 cm3/s and (1.6 +/- 0.8) × 10-14 cm3/s, respectively. Furthermore, we investigate the relationship between the rate coefficient and the mass number of their quenching molecular gases. Firstly, it is confirmed that the rate coefficient take large value with an increase in the mass number of the quenching gases. Secondly, if H atom is included in the gas molecules such as CH4, C2F6 and C3F8 the rate coefficient take large value, but if the molecules including F atom such as C2F6 and C3F8 instead of H atom in this study, more smaller values of the collisional quenching reaction rate coefficient are observed.

  6. Measurements of CCl3F, CCl2F2, CCl4, N2O and SF6 in the Northern Hemisphere stratosphere

    NASA Technical Reports Server (NTRS)

    Leifer, R.; Juzdan, R.

    1985-01-01

    An overview of the Department of Energy's High Altitude Sampling Program and some recent trace gas measurement results are presented. Analysis of whole air samples, collected in pressurized bottles, provides information on stratospheric inventories and distributions for CCl3F, CCl2F2, CCl4, N2O and SF6 in the Northern Hemisphere. Based on a linear regression analysis of the data the estimated mean Northern Hemisphere stratospheric concentration of each gas increased as follows: CCl3F changed from 54 to 142 p1/1 (4/74-11/83); CCl2F2 changed from 133 to 268 p1/1 (4/76-11/83); SF6 changed from 160 to 480 f1/1 (4/74-11/83); CC1, changed from 58 to 91 p1/1 (4/75-11/83); N2O changed from 246 to 261 n1/1 (4/76-11/83). The calculated mean Northern Hemisphere stratospheric concentrations of N2O, CCl3F, CCl2F2, and CCl4 after 1980 show larger than expected fluctuations with time. Recent volcanic activity may be a partial cause for these fluctuations through induced changes in stratospheric dynamical processes.

  7. Thalidomide enhances both primary and secondary host resistances to Listeria monocytogenes infection by a neutrophil-related mechanism in female B6C3F1 mice

    SciTech Connect

    Guo, Tai L. . E-mail: tlguo@hsc.vcu.edu; Chi, Rui P.; Karrow, Niel A.; Zhang, Ling X.; Pruett, Stephen B.; Germolec, Dori R.; White, Kimber L.

    2005-12-15

    Previously, we have reported that thalidomide can modulate the immune responses in female B6C3F1 mice. Furthermore, thalidomide immunomodulation increased primary host resistance to intravenously infected Listeria monocytogenes. The present study was intended to evaluate the mechanisms underlying the enhanced host resistance to L. monocytogenes by focusing on the neutrophils. Female B6C3F1 mice were treated intraperitoneally with thalidomide (100 mg/kg) for 15 days. Exposure to thalidomide increased the numbers of neutrophils in the spleens and livers of L. monocytogenes-infected mice when compared to the L. monocytogenes-infected control mice. Additionally, the percentage of neutrophils was also significantly increased after Thd treatment in L. monocytogenes-infected mice. Further studies using antibodies to deplete corresponding cells indicated that thalidomide-mediated increase in primary host resistance (both the moribundity and colony counts in the liver and spleen) to L. monocytogenes infection was due to its effect on neutrophils but not CD8{sup +} T cells or NK cells. Finally, Thd exposure also increased host resistance to secondary host resistance to L. monocytogenes infection, and depletion of neutrophils abolished the protective effect. In conclusion, thalidomide enhanced host resistance to both primary and secondary L. monocytogenes infections by a neutrophil-related mechanism in female B6C3F1 mice.

  8. New oxyfluoride glass with high fluorine content and laser patterning of nonlinear optical BaAlBO{sub 3}F{sub 2} single crystal line

    SciTech Connect

    Shionozaki, K.; Honma, T.; Komatsu, T.

    2012-11-01

    A new oxyfluoride glass of 50BaF{sub 2}-25Al{sub 2}O{sub 3}-25B{sub 2}O{sub 3} (mol. %) with a large fraction of fluorine, i.e., F/(F + O) = 0.4, was prepared using a conventional melt-quenching method in order to synthesize new glass-ceramics containing nonlinear optical oxyfluoride crystals. The refractive index at 632.8 nm and ultra-violet cutoff wavelength of the glass were 1.564 and {approx}200 nm, respectively. Eu{sup 3+} ions in the glass showed a high quantum yield of 88% in the photoluminescence spectrum in the visible region. BaAlBO{sub 3}F{sub 2} crystals (size: 50-100 nm) showing second harmonic generations were formed through the crystallization of the glass. Lines consisting of BaAlBO{sub 3}F{sub 2} crystals were patterned successfully on the glass surface by laser irradiations (Yb:YVO{sub 4} laser with a wavelength of 1080 nm, laser power of 1.1 W, scanning speed of 8 {mu}m/s). High resolution transmission electron microscope observations combined with a focused ion beam technique indicate that BaAlBO{sub 3}F{sub 2} crystals are highly oriented just like a single crystal. The present study proposes that the new oxyfluoride glass and glass-ceramics prepared have a high potential for optical device applications.

  9. Hepatic DNA adducts and production of mutagenic urine in 2,6-dinitrotoluene-treated B6C3F1 male mice.

    PubMed

    George, S E; Kohan, M J; Warren, S H

    1996-04-19

    The hepatocarcinogen 2,6-dinitrotoluene (2,6-DNT) is an intermediate in the chemical synthesis of 2,4,6-trinitrotoluene and polyurethane products and can contaminate the waste stream emitted by these industries. In this study, the production of mutagenic urine metabolites and the formation of hepatic DNA adducts is examined in the B6C3F1 male mouse. Animals were administered 50 mg/kg 2,6-DNT by gavage for 3 consecutive days. No body or liver weight effects were observed in treated animals. Following sacrifice, the livers were excised and DNA isolated for examination of 2,6-DNT-derived DNA adducts. During 2,6-DNT treatment, urine was collected, concentrated, and tested for mutagenicity in the Salmonella reversion bioassay. Mutagenic urine metabolites (469+/-53 revertants/ml urine) were excreted from B6C3F1 mice treated with 2,6-DNT and were comparable to results obtained for CD-1 mice and Fischer 344 rats. Two distinct hepatic DNA adducts (0.8+/-0.1 and 0.6+/-0.1 RAL/10(8) nucleotides) were detected in B6C3F1 mice by (32)P-postlabeling and thin layer chromatography which differed from the four adducts observed in hepatic DNA from 2,6-DNT-treated Fischer 344 rats.

  10. Synthesis and photoluminescence properties of Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14}:Sm{sup 3+} red phosphor for white light emitting diodes

    SciTech Connect

    Zhu, Ge; Ci, Zhipeng; Shi, Yurong; Wang, Yuhua

    2014-07-01

    Highlights: • A novel red phosphor Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14}:Sm{sup 3+} was synthesized and investigated firstly. • The structure and characteristic luminescence properties are discussed. • The excellent thermal stability was found and investigated. • It has good color saturation, the CIE is close to that of commercial Y{sub 2}O{sub 3}:Eu{sup 3+}. - Abstract: A series of Sm{sup 3+} doped Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14} red phosphors were successfully synthesized. X-ray diffraction analysis indicates that all the samples are single phased. The luminescence property is investigated in detail by measuring their photoluminescence excitation and emission spectra. Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14}:Sm{sup 3+} phosphors show strong absorption in 400–410 nm region, which is suitable for application in LEDs. When excited at 403 nm, Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14}:Sm{sup 3+} phosphor can emit red emission with CIE chromaticity coordinates (0.615, 0.384). The optimal doping concentration of Sm{sup 3+} doped Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14} is measured to be 0.02. The thermal quenching property is also measured and compared with the commercial red phosphor Y{sub 2}O{sub 3}:Eu{sup 3+} (Topstar, TXC-RIA). The results indicate Ca{sub 19}Mg{sub 2}(PO{sub 4}){sub 14}:Sm{sup 3+} phosphors have potential to serve as a red phosphor for white LEDs.

  11. Scintillation properties of Eu2+-doped KBa2I5 and K2BaI4sub>

    SciTech Connect

    Stand, L.; Zhuravleva, M.; Chakoumakos, Bryan C.; Johnson, J.; Lindsey, Adam; Melcher, Charles L.

    2015-09-25

    We report two new ternary metal halide scintillators, KBa2I5 and K2BaI4sub>, activated with divalent europium. Single crystal X-ray diffraction measurements confirmed that KBa2I5 has a monoclinic structure (P21/c) and that K2BaI4sub> has a rhombohedral structure (R3c). Differential scanning calorimetry showed singular melting and crystallization points, making these compounds viable candidates for melt growth. We grew 13 mm diameter single crystals of KBa2I5:Eu2+ and K2BaI4sub>:Eu2+ in evacuated quartz ampoules via the vertical Bridgman technique. The optimal Eu2+ concentration was 4% for KBa2I5 and 7% for K2BaI4sub>. The X-ray excited emissions at 444 nm for KBa2I5:Eu 4% and 448 nm for K2BaI4sub>:Eu 7% arise from the 5d-4f radiative transition in Eu2+. KBa2I5:Eu 4% has a light yield of 90,000 photons/MeV, with an energy resolution of 2.4% and K2BaI4sub>:Eu 7% has a light yield of 63,000 ph/MeV, with an energy resolution of 2.9% at 662 keV. Both crystals have an excellent proportional response to a wide range of gamma-ray energies.

  12. Hydrothermal synthesis, structural and physico-chemical characterizations of two Nasicon phosphates: M{sub 0.50}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (M = Mn, Co)

    SciTech Connect

    Essehli, Rachid; Bali, Brahim El; Benmokhtar, S.; Fejfarova, Karla; Dusek, Michal

    2009-07-01

    The family of titanium Nasicon-phosphates of generic formula M{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} has been revisited using hydrothermal techniques. Two phases have been synthesized: Mn{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (MnTiP) and Co{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (CoTiP). Single crystal diffraction studies show that they exhibit two different structural types. Mn{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} phosphate crystallizes in the R-3 space group, with the cell parameters a = 8.51300(10) A and c = 21.0083(3) A (V = 1318.52(3) A{sup 3} and Z = 6). The Co{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} phosphate crystallizes in the R-3c space group, with a = 8.4608(9) A and c = 21.174(2) A (V = 1312.7(2) A{sup 3} and Z = 6). These two compounds are clearly related to the parent Nasicon-type rhombohedral structure, which can be described using [Ti{sub 2}(PO{sub 4}){sub 3}] framework composed of two [TiO{sub 6}] octahedral interlinked via three [PO{sub 4}] tetrahedra. {sup 31}P magic-angle spinning nuclear magnetic resonance (MAS-NMR) data are presented as supporting data. Curie-Weiss-type behavior is observed in the magnetic susceptibility. The phases are also characterized by IR spectroscopy and UV-visible.

  13. Growth and structure of K{sub 2}Ni{sub x}Co{sub (1–x)}(SO{sub 4}){sub 2} · 6H{sub 2}O single crystals

    SciTech Connect

    Vasilyeva, N. A. Sorokina, N. I.; Antipin, A. M.; Verin, I. A.; Voloshin, A. E.

    2016-01-15

    Single crystals of the K{sub 2}Ni{sub x}Co{sub (1–x)}(SO{sub 4}){sub 2} · 6H{sub 2}O composition are grown by spontaneous flux crystallization. More exact chemical formulas of the single crystals are determined based on the diffraction data as K{sub 2}Co(SO{sub 4}){sub 2} · 6H{sub 2}O (I), K{sub 2}(Co{sub 0.657}Ni{sub 0.343})(SO{sub 4}){sub 2} · 6H{sub 2}O (II), K{sub 2}(Co{sub 0.226}Ni{sub 0.774})(SO{sub 4}){sub 2} · 6H{sub 2}O (III), K{sub 2}(Co{sub 0.216}Ni{sub 0.784})(SO{sub 4}){sub 2} · 6H{sub 2}O (IV), and K{sub 2}Ni(SO{sub 4}){sub 2} · 6H{sub 2}O (V). The substitution of nickel atoms for cobalt atoms in structure I results in a shortening of all (Co,Ni)–O interatomic distances. With increasing Ni concentration, the (Co,Ni)–O2 distance shortens to a lesser degree than the (Co,Ni)–O1 and (Co,Ni)–O3 distances and, as a consequence, the distortion of (Co,Ni)O{sub 6} octahedra decreases. NiO{sub 6} polyhedra are less distorted than CoO{sub 6} octahedra. The analysis of difference syntheses of electron density shows that the number of uninterpretable peaks on the maps of mixed crystals II, III, and IV, as well as on the map of K{sub 2}Co(SO{sub 4}){sub 2} · 6H{sub 2}O, is larger with respect to those of structure K{sub 2}Ni(SO{sub 4}){sub 2} · 6H{sub 2}O.

  14. Synthesis and structural study of a new NASICON-type solid solution: Li{sub 1-} {sub x} La {sub x} {sub /3}Zr{sub 2}(PO{sub 4}){sub 3}

    SciTech Connect

    Barre, M.; Crosnier-Lopez, M.P. Le Berre, F.; Suard, E.; Fourquet, J.L.

    2007-03-15

    A new complete solid solution of NASICON-type compounds between LiZr{sub 2}(PO{sub 4}){sub 3} and La{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} was evidenced with the general formula Li{sub 1-} {sub x} La {sub x} {sub /3}Zr{sub 2}(PO{sub 4}){sub 3} (0{<=}x{<=}1). These phases were synthesized by a complex polymerizable method and structurally characterized from Rietveld treatment of their X-ray and neutron powder diffraction data. This solid solution results from the substitution mechanism Li{sup +{yields}}1/3La{sup 3+}+2/3{open_square} leading to an increase of the vacancies number correlated to an increase of the La content. According to this substitution mechanism, the general formula can then be written Li{sub 1-} {sub x} La {sub x} {sub /3}{open_square}{sub 2} {sub x} {sub /3}Zr{sub 2}(PO{sub 4}){sub 3} (0{<=}x{<=}1) in order to underline the correlation between the La content and the vacancies rate. For all the compounds, the structure is clearly related to that of the NASICON family with three crystallographic domains evidenced. For 0{<=}x{<=}0.5, all the members adopt at high temperature the typical NASICON-type structure (s.g. R3-barc), while at lower temperature, their structure distorts to a triclinic form (s.g. C 1-bar), as observed for LiZr{sub 2}(PO{sub 4}){sub 3} prepared above 1100 deg. C. Moreover, in this domain, the reversible transition is clearly soft and the transition temperature strongly depends of the x value. For 0.6{<=}x{<=}0.9, the compounds crystallize in a rhombohedral cell (s.g. R3-bar), while for x=1, the phase La{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} is obtained (s.g. P3-bar, Z=6, a=8.7378(2) A, c=23.2156(7) A). This paper is devoted to the structure analysis of the series Li{sub 1-} {sub x} La {sub x} {sub /3}Zr{sub 2}(PO{sub 4}){sub 3} (0{<=}x{<=}1), from X-ray and neutron powder thermo diffraction and transmission electron microscopy (TEM) studies. - Graphical abstract: Schematic drawing of the space group evolution at 800 deg. C in the

  15. Characterization of collision cascade damage in Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} by HRTEM

    SciTech Connect

    Weber, W.J.; Wang, L.M.

    1994-12-01

    Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} thin crystals become amorphous under ion beam irradiation. The ion dose required for complete amorphization of the thin crystal (critical amorphization dose, D{sub c}) increased with the increasing irradiation temperature and decreased with ion mass at elevated temperatures. Samples irradiated with 1-1.5 MeV Ar{sup +}, Kr{sup +} and Xe{sup +} ions to doses much lower than Dc, in the temperature range from 20 to 498 K were used for a detailed HRTEM study to better understand the amorphization process. The residual collision cascade damage after irradiation appeared as manometer scale amorphous domains. The images of these domains are extremely sensitive to the sample thickness. Small domains of cascade size were only found at the very thin edge of the sample. In thicker regions, amorphous domains appear after higher doses as the result of cascade overlap in projection. At higher temperatures, the observed amorphous domains are smaller indicating thermal recovery at the amorphous/crystalline interface. The amorphous domains are also larger in size after irradiation with ions of higher mass at a fixed ion dose. These results are consistent with the Dc-temperature curves determined by in situ TEM with the HVEM-Tandem Facility at Argonne National Laboratory. The width of the amorphous rim along the edge of the specimen grew with increasing ion dose suggesting that amorphization also proceeds from the sample surface. Images of the collision cascade damage were compared to the cascade sizes calculated with the TRIM code. Some digitally acquired HRTEM images of the cascade damage were processed to reveal more detailed information.

  16. A Raman spectroscopic study of the phase transition of BaZr(PO{sub 4}){sub 2}: Evidence for a trigonal structure of the high-temperature polymorph

    SciTech Connect

    Geisler, Thorsten . E-mail: tgeisler@nwz.uni-muenster.de; Popa, Karin; Konings, Rudy J.M.; Popa, Aurelian F.

    2006-05-15

    We have studied the structural evolution of monoclinic BaZr(PO{sub 4}){sub 2} during heating up to 835K by Raman spectroscopy. In agreement with previous studies we found a first-order phase transition at about 730K during heating while upon cooling the reverse transition occurs at 705K. However, some disagreement about the crystal structure of the high-temperature polymorph occurs in the literature. While the space group has not yet been determined, the X-ray diffraction pattern of the high-temperature phase has been indexed on either an orthorhombic or a hexagonal unit cell. We found that the number of Raman active internal PO{sub 4} vibrational modes decrease from nine to six during the transition. A group theoretical survey through all orthorhombic, trigonal, and hexagonal factor groups revealed that the observed number of vibrations would only be consistent with the Ba and Zr atoms located at a D{sub 3d}(3-bar m) site, the P and two O atoms at a C{sub 3v}(3m), and six O atoms at a C{sub s}(m) site in the D{sub 3d} factor group. Based on our Raman data, the space group of the high-temperature polymorph is thus either D{sub 3d}{sup 1}(P3-bar 1m), D{sub 3d}{sup 3}(P3-bar m1), or D{sub 3d}{sup 5}(R3-bar m)

  17. HERSCHEL /HIFI OBSERVATIONS OF A NEW INTERSTELLAR WATER MASER: THE 5{sub 32}-4{sub 41} TRANSITION AT 620.701 GHz

    SciTech Connect

    Neufeld, David A.; Wu, Yuanwei; Kraus, Alex; Menten, Karl M.; Tolls, Volker; Melnick, Gary J.; Nagy, Zsofia

    2013-05-20

    Using the Herschel Space Observatory's Heterodyne Instrument for the Far-Infrared, we have performed mapping observations of the 620.701 GHz 5{sub 32}-4{sub 41} transition of ortho-H{sub 2}O within a {approx}1.'5 Multiplication-Sign 1.'5 region encompassing the Kleinmann-Low nebula in Orion (Orion-KL), and pointed observations of that transition toward the Orion South condensation and the W49N region of high-mass star formation. Using the Effelsberg 100 m radio telescope, we obtained ancillary observations of the 22.23508 GHz 6{sub 16}-5{sub 23} water maser transition; in the case of Orion-KL, the 621 GHz and 22 GHz observations were carried out within 10 days of each other. The 621 GHz water line emission shows clear evidence for strong maser amplification in all three sources, exhibiting narrow ({approx}1 km s{sup -1} FWHM) emission features that are coincident (kinematically and/or spatially) with observed 22 GHz features. Moreover, in the case of W49N-for which observations were available at three epochs spanning a 2 yr period-the spectra exhibited variability. The observed 621 GHz/22 GHz line ratios are consistent with a maser pumping model in which the population inversions arise from the combined effects of collisional excitation and spontaneous radiative decay, and the inferred physical conditions can plausibly arise in gas heated by either dissociative or non-dissociative shocks. The collisional excitation model also predicts that the 22 GHz population inversion will be quenched at higher densities than that of the 621 GHz transition, providing a natural explanation for the observational fact that 22 GHz maser emission appears to be a necessary but insufficient condition for 621 GHz maser emission.

  18. Hydrothermal synthesis, thermal, structural, spectroscopic and magnetic studies of the Mn{sub 5-} {sub x} Co {sub x} (HPO{sub 4}){sub 2}(PO{sub 4}){sub 2}(H{sub 2}O){sub 4} (x=1.25, 2, 2.5 and 3) finite solid solution

    SciTech Connect

    Larrea, Edurne S.

    2007-05-15

    The Mn{sub 5-} {sub x} Co {sub x} (HPO{sub 4}){sub 2}(PO{sub 4}){sub 2}(H{sub 2}O){sub 4} (x=1.25, 2, 2.5, 3) finite solid solution has been synthesized by mild hydrothermal conditions under autogeneous pressure. The phases crystallize in the C2/c space group with Z=4, belonging to the monoclinic system. The unit-cell parameters obtained from single crystal X-ray diffraction are: a=17.525(1), b=9.0535(6), c=9.4517(7) A, {beta}=96.633(5) {sup o} being R1=0.0436, wR2=0.0454 for Mn75Co25; a=17.444(2), b=9.0093(9), c=9.400(1) A, {beta}=96.76(1) {sup o} being R1=0.0381, wR2=0.0490 for Mn60Co40; a=17.433(2), b=8.9989(9), c=9.405(1) A, {beta}=96.662(9) {sup o} being R1=0.0438, wR2=0.0515 for Mn50Co50 and a=17.4257(9), b=8.9869(5), c=9.3935(5) A, {beta}=96.685(4) {sup o} being R1=0.0296, wR2=0.0460 for Mn40Co60. The structure consists of a three dimensional network formed by octahedral pentameric entities (Mn,Co){sub 5}O{sub 16}(H{sub 2}O){sub 6} sharing vertices with the (PO{sub 4}){sup 3-} and (HPO{sub 4}){sup 2-} tetrahedra. The limit of thermal stability of these compounds is, approximately, 165 deg. C, near to this mean temperature the phases loose their water content in two successive steps. IR spectra show the characteristic bands of the water molecules and the phosphate and hydrogen-phosphate oxoanions. The diffuse reflectance spectra are consistent with the presence of MO{sub 6} octahedra environments in slightly distorted octahedral geometry, except for the M(3)O{sub 6} octahedron which presents a remarkable distortion and so a higher Dq parameter. The mean value for the Dq and B-Racah parameter for the M(1),(2)O{sub 6} octahedra is 685 and 850 cm{sup -1}, respectively. These parameters for the most distorted M(3)O{sub 6} polyhedron are 825 and 880 cm{sup -1}, respectively. The four phases exhibit antiferromagnetic couplings as the major magnetic interactions. However, a small spin canting phenomenon is observed at low temperatures for the two phases with major

  19. Magnetic field, frequency and temperature dependence of complex conductance of ultrathin La1.65Sr0.45CuO4sub>/La2CuO4sub> films and the organic superconductors κ-(BEDT-TTF)2Cu[N(CN)2]Br

    SciTech Connect

    V. A. Gasparov; Bozovic, I.; He, Xi; Dubuis, G.; Pavuna, D.; Kushch, N. D.; Yagubskii, E. B.; Schlueter, J. A.

    2015-09-01

    In this study, we used atomic-layer molecular beam epitaxy (ALL-MBE) to synthesize bilayer films of a cuprate metal (La1.65Sr0.45CuO4sub>) and a cuprate insulator (La2CuO4sub>), in which interface superconductivity occurs in a layer that is just one-half unit cell thick. We have studied the magnetic field and temperature dependence of the complex sheet conductance, σ(ω), of these films, and compared them to κκ-(BEDT-TTF)2Cu[N(CN)2]Br single crystals. The magnetic field H was applied both parallel and perpendicular to the 2D conducting layers. Experiments have been carried out at frequencies between 23 kHz and 50 MHz using either two-coil mutual inductance technique, or the LC resonators with spiral or rectangular coils. The real and the imaginary parts of the mutual-inductance M(T,ω) between the coil and the sample were measured and converted to complex conductivity. For H perpendicular to the conducting layers, we observed almost identical behavior in both films and κ-Br single crystals: (i) the transition onset in the inductive response, Lk–1(T) occurs at a temperature lower by 2 K than in Re σ(T), (ii) this shift is almost constant with magnetic field up to 8 T; (iii) the vortex diffusion constant D(T) is exponential due to pinning of vortex cores. These results can be described by the extended dynamic theory of the Berezinski–Kosterlitz–Thouless (BKT) transition and dynamics of bound vortex–antivortex pairs with short separation lengths.

  20. Fundamental Understanding of Methane-Carbon Dioxide-Water (CH4sub>-CO2-H2O) Interactions in Shale Nanopores under Reservoir Conditions. Quarterly Report.

    SciTech Connect

    Wang, Yifeng

    2015-10-27

    This project focuses on the systematic study of CH4sub>-CO2-H2O interactions in shale nanopores under high-pressure and high temperature reservoir conditions. The proposed work will help to develop new stimulation strategies to enable efficient resource recovery from fewer and less environmentally impactful wells.

  1. Ion-redistribution induced efficient upconversion in β-NaYF4sub>:20%Yb3+,2%Er3+ microcrystals with well controlled morphology and size.

    PubMed

    Fan, Shaohua; Wang, Shikai; Yu, Lu; Sun, Hongtao; Gao, Guojun; Hu, Lili

    2017-01-09

    We develop an efficient green upconversion (UC) β-NaYF4sub>:20%Yb3+,2%Er3+ microcrystal with well controlled morphology and size by hydrothermal method using two different chelating agents of CIT and EDTA-2Na via a simple ion-exchange reaction. Importantly, the UC emission efficiency of newly developed CIT and EDTA-2Na β-NaYF4sub>:20%Yb3+,2%Er3+ microcrystals is almost as strong as that of commercial counterpart by solid-state method. A proof-of-concept β-NaYF4sub>:20%Yb3+,2%Er3+ microcrystal waveguide is demonstrated to extend their applications in modern micro-optoelectronics. The local ion-redistribution process during the ion-exchange reaction, which effectively disperses the locally clustered Yb3+, accounts for the enormously enhanced UC emission in β-NaYF4sub>:20%Yb3+,2%Er3+ microcrystals.

  2. Syntheses and crystal structures of two novel alkaline uranyl chromates A{sub 2}(UO{sub 2})(CrO{sub 4}){sub 2} (A=Rb, Cs) with bidentate coordination mode of uranyl ions by chromate anions

    SciTech Connect

    Siidra, Oleg I.

    2012-03-15

    Single crystals of Cs{sub 2}(UO{sub 2})(CrO{sub 4}){sub 2} and Rb{sub 2}(UO{sub 2})(CrO{sub 4}){sub 2} were prepared by solid state reactions. The structures are based upon the [(UO{sub 2})(CrO{sub 4}){sub 2}]{sup 2-} chains. Within the chains, UrO{sub 5} pentagonal bipyramids (Ur=uranyl) form Ur{sub 2}O{sub 8} dimers, which are linked via CrO{sub 4} tetrahedra into one-dimensional chains. The CrO{sub 4} tetrahedra coordinate uranyl ions in both mono- and bidentate fashion, which is unusual for uranyl chromates. The bidentate coordination has a strong influence upon geometrical parameters of both U and Cr coordination polyhedra. The conformation of the chains in 1 and 2 is different due to the different size of the Cs{sup +} and Rb{sup +} cations. - Graphical abstract: Uranyl chromate chain with monodentate and bidentate coordination mode of uranyl cations by CrO{sub 4} tetrahedra in Cs{sub 2}(UO{sub 2})(CrO{sub 4}){sub 2}. Highlights: Black-Right-Pointing-Pointer Single crystals of novel uranyl chromates were prepared by solid state reactions. Black-Right-Pointing-Pointer The CrO{sub 4} tetrahedra coordinate uranyl ions in both mono- and bidentate fashion. Black-Right-Pointing-Pointer The bidentate coordination has a strong influence upon geometrical parameters.

  3. Longitudinally diode-pumped 1.06-{mu}m Nd{sup 3+}:NaLa(MoO{sub 4}){sub 2} laser without pump-wavelength stabilisation

    SciTech Connect

    Zharikov, Evgeny V; Lis, Denis A; Subbotin, Kirill A; Ushakov, S N; Onishchenko, A M; Romanyuk, V A; Shestakov, A V

    2006-01-31

    The spectral and lasing characteristics of a Nd{sup 3+}:NaLa(MoO{sub 4}){sub 2} crystal longitudinally diode-pumped without pump-wavelength stabilisation are studied. A variation in the output power did not exceed 30% when the pump wavelength was changed in the spectral region from 0.794 to 0.811 {mu}m. (lasers)

  4. pH-regulative synthesis of Na3(VPO4sub>)2F3 nanoflowers and their improved Na cycling stability

    SciTech Connect

    Qi, Yuruo; Mu, Linqin; Zhao, Junmei; Hu, Yong -Sheng; Liu, Huizhou; Dai, Sheng

    2016-04-08

    Na-ion batteries are becoming increasingly attractive as a low cost energy storage device. Sodium vanadium fluorophosphates have been studied extensively recently due to their high storage capacity and high discharge voltage. Shape and size often have a crucial influence over the properties. The controlling synthesis of nanoparticles with special microstructures is significant, which becomes a challenging issue and has drawn considerable attention. In this study, Na3(VPO4sub>)2F3 nanoflowers have been synthesized via a pH-regulative low-temperature (120 °C) hydro-thermal route. In particular, it is a green route without any organic compounds involved. The hydro-thermal reaction time for the formation of Na3(VPO4sub>)2F3 nanoflowers has also been investigated. A weak acid environment (pH = 2.60) with the possible presence of hydrogen fluoride molecules is necessary for the formation of the desired nanoflower microstructures. Moreover, compared to the nanoparticles obtained by Na2HPO4sub>·12H2O, the as-synthesized Na3(VPO4sub>)2F3 nanoflowers showed an excellent Na-storage performance in terms of superior cycle stability, even without any further carbon coating or high-temperature treatment.

  5. In situ determination of the spinel-post-spinel transition in Fe3O4sub> at high pressure and temperature by synchrotron X-ray diffraction

    SciTech Connect

    Schollenbruch, K; Woodland, A B; Frost, D J; Wang, Y; Sanehira, T; Langenhorst, F

    2011-08-10

    The position of the spinel-post-spinel phase transition in Fe3O4sub> has been determined in pressure-temperature space by in situ measurements using a multi-anvil press combined with white synchrotron radiation. Pressure measurement using the equation of state for MgO permitted pressure changes to be monitored at high temperature. The phase boundary was determined by the first appearance of diffraction peaks of the high-pressure polymorph (h-Fe3O4sub>) during pressure increase and the disappearance of these peaks on pressure decrease along several isotherms. We intersected the phase boundary over the temperature interval of 700-1400 ºC. The boundary is linear and nearly isobaric, with a slightly positive slope. Post-experiment investigation by TEM confirms that the reverse reaction from h-Fe 3O4sub> to magnetite during decompression leads to the formation of microtwins on the (311) plane in the newly formed magnetite. Observations made during the phase transition suggest that the transition has a pseudomartensitic character, explaining in part why magnetite persists at conditions well within the stability field of h-Fe3O4sub>, even at high temperatures. This study emphasizes the utility of studying phase transitions in situ at simultaneously high temperatures and pressures since the reaction kinetics may not be favorable at room temperature.

  6. Origin of Active Oxygen in a Ternary CuOx /Co3O4sub>–CeO 2 Catalyst for CO Oxidation

    SciTech Connect

    Liu, Zhigang; Wu, Zili; Peng, Xihong; Binder, Andrew; Chai, Songhai; Dai, Sheng

    2014-11-14

    In this paper, we have studied CO oxidation over a ternary CuOx/Co3O4sub>-CeO2 catalyst and employed the techniques of N2 adsorption/desporption, XRD, TPR, TEM, in situ DRIFTS and QMS (Quadrupole mass spectrometer) to explore the origin of active oxygen. DRIFTS-QMS results with labeled 18O2 indicate that the origin of active oxygens in CuOx/Co3O4sub>-CeO2 obeys a model, called as queue mechanism. Namely gas-phase molecular oxygens are dissociated to atomic oxygens and then incorporate in oxygen vacancies located at the interface of Co3O4sub>-CeO2 to form active crystalline oxygens, and these active oxygens diffuse to the CO-Cu+ sites thanks to the oxygen vacancy concentration magnitude and react with the activated CO to form CO2. This process, obeying a queue rule, provides active oxygens to form CO2 from gas-phase O2 via oxygen vacancies and crystalline oxygen at the interface of Co3O4sub>-CeO2.

  7. NaLa(MoO{sub 4}){sub 2}: RE{sup 3+} (RE{sup 3+} = Eu{sup 3+}, Sm{sup 3+}, Er{sup 3+}/Yb{sup 3+}) microspheres: the synthesis and optical properties

    SciTech Connect

    Gao, Zhiyi; Wang, Zhiying; Fu, Linlin; Yang, Xingxing; Fu, Zuoling; Wu, Zhijian; Jeong, Jung Hyun

    2015-10-15

    The strong green upconversion (UC) emission were observed in various Er{sup 3+}, Yb{sup 3+} co-doped NaLa(MoO{sub 4}){sub 2} samples synthesized via a hydrothermal route. The UC intensity depends on the dopant concentration, and the optimal UC emission was obtained in NaLa(MoO{sub 4}){sub 2}: 0.02Er{sup 3+}/0.10 Yb{sup 3+}. - Highlights: • The NaLa(MoO{sub 4}){sub 2} microspheres doped with Eu{sup 3+}, Sm{sup 3+} and Er{sup 3+}/Yb{sup 3+} were synthesized by a hydrothermal method. • The effects of the EDTA in the initial solution crystal phase and morphology were studied. • The down-conversion luminescence properties of NaLa(MoO{sub 4}){sub 2}: RE{sup 3+} (RE{sup 3+} = Eu{sup 3+}, Sm{sup 3+}) were investigated. • The UC luminescence properties and mechanism of Er{sup 3+}/Yb{sup 3+} co-doped NaLa(MoO{sub 4}){sub 2} was discussed. - Abstract: NaLa(MoO{sub 4}){sub 2}: RE{sup 3+} (RE{sup 3+} = Eu{sup 3+}, Sm{sup 3+}) microspheres have been synthesized at 180 °C via a facile EDTA-mediated hydrothermal route. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), photoluminescence (PL) spectra were employed to characterize the samples. It was found that the amount of EDTA in the initial solution was responsible for crystal phase and shape determination. The effect of Eu{sup 3+} and Sm{sup 3+} doping concentrations on the luminescent intensity was also investigated in details. Furthermore, the up-conversion (UC) emissions have been observed in a series of Er{sup 3+}/Yb{sup 3+} co-doped NaLa(MoO{sub 4}){sub 2} samples. Concentration dependent studies revealed that the optimal composition was realized for a 2% Er{sup 3+} and 10% Yb{sup 3+}-doping concentration.

  8. Ultrasmall, water dispersible, TWEEN80 modified Yb:Er:NaGd(WO4sub>)2 nanoparticles with record upconversion ratiometric thermal sensitivity and their internalization by mesenchymal stem cells.

    PubMed

    Cascales, Concepcion; Paino, Carlos; Bazán, Eulalia; Zaldo, Carlos

    2017-03-21

    This work presents the synthesis by coprecipitation of diamond shaped Yb:Er:NaGd(WO4sub>)2 crystalline nanoparticles (NPs) with diagonal dimensions in the 5-7 nm × 10-12 nm range which have been modified with TWEEN80 for their dispersion in water, and their interaction with mesenchymal stem cells (MSCs) proposed as cellular NP vehicles. These NPs belong to a large family of tetragonal Yb:Er:NaT(XO4sub>)2 (T=Y, La, Gd, Lu; X= Mo, W) compounds with green (2H11/2+4S3/24I15/2) Er-related upconversion (UC) efficiency comparable to that of Yb:Er:β-NaYF4sub> reference compound, but with a ratiometric thermal sensitivity (S) 2.5-3.5 times larger than that of the fluoride. At the temperature range of interest for biomedical applications (~293-317 K / 20-44 ºC) S= 108-118 × 10-4 K-1 for 20at%Yb:5at%Er:NaGd(WO4sub>)2 NPs, being the largest values so far reported using the 2H11/2/4S3/2 Er intensity ratiometric method. Cultured MSCs, incubated with these water NP emulsions, internalize and accumulate the NPs enclosed in endosomes/lysosomes. Incubations with up to 10 μg of NPs per ml of culture medium maintain cellular metabolism at 72 h. A thermal assisted excitation path is discussed as responsible for the UC behavior of Yb:Er:NaT(XO4sub>)2 compounds.

  9. A study of room-temperature LixMn1.5Ni0.5O4sub> solid solutions

    SciTech Connect

    Saravanan, Kuppan; Jarry, Angelique; Kostecki, Robert; Chen, Guoying

    2015-01-26

    Understanding the kinetic implication of solid-solution vs. biphasic reaction pathways is critical for the development of advanced intercalation electrode materials. Yet this has been a long-standing challenge in materials science due to the elusive metastable nature of solid solution phases. The present study reports the synthesis, isolation, and characterization of room-temperature LixMn1.5Ni0.5O4sub> solid solutions. In situ XRD studies performed on pristine and chemically-delithiated, micron-sized single crystals reveal the thermal behavior of LixMn1.5Ni0.5O4sub> (0 ≤ x ≤ 1) cathode material consisting of three cubic phases: LiMn1.5Ni0.5O4sub> (Phase I), Li0.5Mn1.5Ni0.5O4sub> (Phase II) and Mn1.5Ni0.5O4sub> (Phase III). A phase diagram capturing the structural changes as functions of both temperature and Li content was established. In conclusion, the work not only demonstrates the possibility of synthesizing alternative electrode materials that are metastable in nature, but also enables in-depth evaluation on the physical, electrochemical and kinetic properties of transient intermediate phases and their role in battery electrode performance.

  10. Small molecular probe as selective tritopic sensor of Al(3+), F(-) and TNP: Fabrication of portable prototype for onsite detection of explosive TNP.

    PubMed

    Ghosh, Pritam; Banerjee, Priyabrata

    2017-05-01

    Schiff base organic compound (SOC) has been prepared as a tritopic chemosensor for selective sensing by fluorescence signalling towards ions like Al(3+), F(-) and explosive molecule like TNP. In general, fluorescence like photophysical property has been used for selective detection of analyte where Al(3+) and F(-) show turn-on fluorescence signal at different wavelengths (nm) however, quenching was found with TNP. As a consequence, the chemosensor has become a selective sensor for Al(3+), F(-) and TNP. Reversibility of fluorescence responses for Al(3+) and F(-) are observed in presence of ammonium nitrate and H(+) respectively. Similar to the detection of TNP, the detection of explosive like NO3(-) salts is also essential from homeland security point of view. In the present work, the finding of reversible sequential fluorescence response can be promoted for fabrication of next generation AND-NOT-OR-NAND-XOR-XNOR-NOR based complex logic circuit which is applicable in photonics, security and other fields including inorganic and material science. In the case of TNP recognition, the pathway mainly depends on non-covalent interaction (quenching constant: 4.4 × 10(5) M(-1)) which is even better than the recently reported materials. Detection limit for Al(3+), F(-) and TNP is 1 μM, 3 μM and 500 nM respectively. DFT-D3 has been carried out to explore the host⋯guest interaction along with the structure-property correlation of the present host-guest system. All three guest analytes have been detected inside the living cell at a certain level and in its consequence, the successful in vitro recognition ability of the SOCs inside human cell line HeLa has been explored too. In real time stepping, an easy to operate and an economically affordable pocket prototype has also been fabricated for on spot detection of TNP like explosive.

  11. Pump and Probe Spectroscopy of CH_3F-({ortho}-H_2){n} Clusters in Solid Parahydrogen by Using Two Cw-Ir Quantum Cascade Lasers

    NASA Astrophysics Data System (ADS)

    Kawasaki, Hiroyuki; Mizoguchi, Asao; Kanamori, Hideto

    2016-06-01

    The absorption spectrum of the ν3 (C-F stretching) mode of CH_3F in solid {para}-H_2 by FTIR showed a series of equal interval peaks Their interpretation was that the {n}-th peak of this series was due to CH_3F-({ortho}-H_2){n} clusters which were formed CH_3F and {n}'s {ortho}-H_2 in first nearest neighbor sites of the {para}-H_2 crystal with {hcp} structure. In order to understand this system in more detail, we have studied these peaks, especially {n} = 0 - 3 corresponding to 1037 - 1041 wn, by using high-resolution and high-sensitive infrared quantum cascade laser (QCL) spectroscopy. Before now, we have observed photochromic phenomena of these peaks by taking an advantage of the high brightness of the laser. However, it has not been revealed what kind of mechanism is undergoing in these processes. In order to solve this problem we introduced two cw-IR QCLs for pump and prove experiment. While the pumping laser is breaching a certain peak with high power, the probing laser is monitoring the increase of other peaks by rapid scan method. The time resolution of this spectroscopy is 5 msec. The new precise kinetic information will help us to understand the molecular interaction in solid {para}-H_2. K. Yoshioka and D. T. Anderson, J. Chem. Phys. 119 (2003) 4731-4742 A. R. W. McKellar, A. Mizoguchi, and H. Kanamori, Phys. Chem. Chem. Phys. 13 (2011) 11587-11589

  12. Comparison of the toxicity of several fumonisin derivatives in a 28-day feeding study with female B6C3F(1) mice.

    PubMed

    Howard, Paul C; Couch, Letha H; Patton, Ralph E; Eppley, Robert M; Doerge, Daniel R; Churchwell, Mona I; Marques, M Matilde; Okerberg, Carlin V

    2002-12-15

    Fumonisinmycotoxins are produced by Fusaria fungi that grow worldwide primarily on corn. Fumonisin B(1), the most predominant form in corn samples, is a renal carcinogen in male F344/N rats and a hepatocarcinogen in female B6C3F(1) mice when fed at concentrations higher than 50 ppm (70 micromol/kg) in the diet for 2 years. We sought to determine the relative toxicities of several naturally occurring fumonisin derivatives when included in the diet of female B6C3F(1) mice. Mice were fed diets containing fumonisin B(1), fumonisin B(2), fumonisin B(3), fumonisin P1, hydrolyzed-fumonisin B(1), N-(acetyl)fumonisin B(1), or N-(carboxymethyl)fumonisin B(1) (approximately 0, 14, 70, and 140 micromol/kg diet) for 28 days. None of the doses used caused a decrease in body weight gain over the 28 days. Serum levels of total bile acids, cholesterol, and alkaline phosphatase were increased only in mice receiving 72 and 143 micromol/kg fumonisin B(1), suggesting that only fumonisin B(1) was hepatotoxic in the mice. Corroborating this observation, the liver weight, relative to body weight, was decreased only in the mice that consumed 143 micromol/kg fumonisin B(1). Consistent with fumonisin B(1) inhibition of ceramide synthase, the liver sphinganine-to-sphingosine ratio was increased and the liver ceramide levels were decreased only in the mice receiving 72 and 143 micromol/kg fumonisin B(1). Increased hepatocellular