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Sample records for ce na korrozionnye

  1. File list: NoD.CeL.50.NA.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.CeL.50.NA.AllCell dm3 No description NA Cell line ERX242709,ERX102369,ERX102367...242717,ERX402109,ERX242722,ERX242721,ERX242706,ERX242710,ERX242714,ERX242725,ERX242715 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/NoD.CeL.50.NA.AllCell.bed ...

  2. Effects of toluene on thiophene adsorption over NaY and Ce(IV)Y zeolites

    Institute of Scientific and Technical Information of China (English)

    Yanchun Shi; Xiaojian Yang; Fuping Tian; Cuiying Jia; Yongying Chen

    2012-01-01

    Zeolites NaY and Ce(IV)Y were employed as adsorbents to remove organic sulfur compounds from model gasoline (MG) solutions with and without toluene in static adsorption experiments at room temperature (RT) and atmospheric pressure.The adsorbents were characterized by XRD,XRF and pyridine infrared spectrum (IR).The adsorption experiments show that the desulfurization performance of Ce(IV)Y is much better than that of NaY.The sulfur removal over both NaY and Ce(IV)Y decreases with the increase of toluene concentration in MG,however,the decline tendency on Ce(IV)Y is smooth,and it is steep on NaY.FT-IR spectra of thiophene adsorption indicate that thiophene molecules are mainly adsorbed on NaY via π electron interaction,but on Ce(IV)Y,in addition to the π electron interaction,both Ce4+-S direct interaction and protonation of thiophene also play important roles.Toluene molecules are adsorbed on NaY also via π electron interaction.Although the amount of Br(o)nsted acid sites is increased due to the introduction of Ce4+ ions into NaY zeolite,it is not found to influence the adsorption mode of toluene over Ce(IV)Y.Compared with NaY zeolite,the improved desulfurization performance over Ce(IV)Y for removing organic sulfur compounds from MG solution,especially those containing large amount of aromatics,may be ascribed to the direct Ce(IV)-S interaction,which is much resistant to the influence resulted from toluene adsorption.

  3. Biological reduction-deposition and luminescent properties of nanostructured CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiaoniu [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Research Institute of Green Construction Materials, Southeast University, Nanjing 211189 (China); Qian, Chunxiang, E-mail: cxqian@seu.edu.cn [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Research Institute of Green Construction Materials, Southeast University, Nanjing 211189 (China)

    2016-03-01

    Nano-sized CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4} with hexagonal phase have been prepared by simply varying the reactant P/Ce molar ratio in bacterial liquid. The phase composition of two samples was checked via Fourier transform infrared spectroscopy (FTIR), energy dispersive analysis of X-rays (EDS) and X-ray diffraction (XRD) analyses, displaying the presence of CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4} with average crystallite size are 32.34 and 15.61 nm, respectively. The scanning electron microscopy (SEM) images show that nano-clusters and sphere-like in shape with a narrow diameter distribution were observed in two samples. The transmission electron microscopy (TEM) photographs further indicate obtained CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4} nanoparticles correspond to nanosheets and nanorods, respectively. The emission spectra of CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4} display a broad band of 300–380 nm range with the strongest emission at 342 nm in the violet region. - Highlights: • A new method was found to synthesize CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4} nanoparticles. • CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) nanoparticles have good luminescent properties. • Size and luminescent properties of two samples have been studied and compared.

  4. Structure and heat capacity of the NaCeF4 compound

    Institute of Scientific and Technical Information of China (English)

    Virgil Constantin; Ana-Maria Popescu

    2013-01-01

    This work continued our general research program on obtaining metallic cerium by electrodeposition from NaCeF4 dis-solved in different molten fluorides. The structure of NaCeF4 (cubic or hexagonal depending on the way of preparation) was estab-lished by DTA analysis, IR spectra and X-ray diffraction. The heat capacity (Cp) of NaCeF4 was measured by differential scanning calorimetry in the temperature range of 300-1093 K using the“step-method”. The Cp was fitted by an equation with a satisfactory re-sult. Heat capacity was compared with that calculated from the Neumann-Kopp rule (NKR) and the deviations observed were consis-tent with the stability of the NaCeF4 compound.

  5. Electrochemical behaviors of anodic alumina sealed by Ce-Mo in NaCl solutions

    Institute of Scientific and Technical Information of China (English)

    TIAN Lian-peng; ZHAO Xu-hui; ZHAO Jing-mao; ZHANG Xiao-feng; ZUO Yu

    2006-01-01

    The elimination of toxic materials in sealing methods for anodic films on 1070 aluminum alloy was studied. The new process uses chemical treatments in cerium solution and an electrochemical treatment in a molybdate solution. Potentiodynamic polarization and electrochemical impedance spectroscopy(EIS) were used to study the influences of sealing methods on the corrosion behavior of anodic films in NaCl solutions. The results show that the Ce-Mo sealing makes the surface structure and morphology of anodic films uniform and compact. Ce and Mo produce a cooperative effect to improve the corrosion resistance of anodic films. Anodic films sealed by Ce-Mo provide high corrosion resistance both in acidic and basic solutions.

  6. Luminescence, Energy Transfer and Tunable Color of Ce3+- and Tb3+-Activated Na3Gd(BO3)2 Phosphors

    Science.gov (United States)

    Zhang, Xinguo; Pan, Jialiang; Mo, Fuwang

    2017-02-01

    A series of blue Na3Gd(BO3)2:Ce3+ and blue-to-green color-tunable Na3Gd (BO3)2:Ce3+,Tb3+ phosphors were synthesized by the solid-state method. The luminescence, concentration quenching and energy transfer (ET) process of Na3Gd(BO3)2:Ce3+,Tb3+ were investigated. Both Ce3+ and Tb3+ occupy the Gd3+ site in the Na3Gd(BO3)2 host. Na3Gd(BO3)2:Ce3+ exhibits strong ultraviolet absorption and broadband blue emission. The Ce3+ sensitization effect on Tb3+ has been verified by the variation of PL/PLE spectra, the Ce3+ decay lifetimes and the energy transfer efficiency of Na3Gd(BO3)2:Ce3+,Tb3+ phosphors. The maximum Ce3+-Tb3+ ET efficiency has been calculated to be 95%. The emitting color of the obtained phosphors can be modulated from blue (0.179, 0.204) through bluish-green (0.271, 0.391) to green (0.349, 0.551) by properly changing the ratio of Ce3+/Tb3+.

  7. Mild Hydrothermal Synthesis, Characterizationand Properties of Na5Ce(PO4)3, Na3Yb2(PO4)3 ·H2O and Na5-2xYb2xCe1-x(PO4)3 · yH2O

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Novel phosphates, Na5-2xYb2xCe1-x (PO4) 3 · yH2O (x = 0-1, y = 0-1 ), were synthesizedunder mild hydrothermal conditions at 240 C with Ce(SO4)2 · H2O, Ce(SO4)2 · 2(NH4)2SO4 ·4H2O, CeO2, Yb2O3, 85 % H3PO4 and NaOH as the starting materials. The products were sensitively influenced by the pH value of the systems and reaction temperature. Under an acidic condition, CePO4 was the product at 240 C, in which Ce( Ⅳ ) species was reduced to Ce( Ⅲ ) species.Under a weak basic condition, Na2Ce(PO4)2 · 0. 79H2O was produced. Under a medium basiccondition, the expected compound Na5Ce (PO4)3 was the product. Under a basic condition, CeO2was the final product, amorphous phase was also produced in some cases. The structure of thecompounds were investigated by X-ray diffraction, SEM, IR, Raman, 31P MAS NMR and XPSspectroscopies. To determine the valence of Ce in the compound, EPR and DRS of the compoundwere also recorded. The thermal properties of the compounds were determined with DTA-TGanalysis. Na5Ce(PO4)3 was decomposed into Na3Ce(PO4)2, Na4P2O7 and O2 at 694 C, in whichCe( Ⅳ ) was reduced to Ce( Ⅲ ) species. Na3Yb2(PO4)3 · H2O lost water and was transferred intoa new phase at a high temperature 682 C. The thermal stability of Na5-2xYb2xCe1-x(PO4)3 ·yH2O could be improved by increasing x value. When x= 0. 54, the compound was stable evenat the temperature ca. 1 000 C. The ionic conductivities of the compounds were increased whenthe amount of Yb in the compound was increased and when x=0. 33, it reached the highest value (σ300 c=3.96×10-6 S · cm-1).

  8. Study of luminescence and effect of Dy3+ on NaMgSO4 Cl:Ce chlorosulphate phosphor.

    Science.gov (United States)

    Choubey, Sureshkumar R; Gedam, Sharadkumar C; Dhoble, Sanjay J

    2014-12-01

    Chlorosulphate NaMgSO4 Cl phosphor doped with Ce(3+) and co-doped by Dy(3+) prepared by the wet chemical method was studied for its photoluminescence and thermoluminescence (TL) characteristics. The emission spectrum of Ce(3+) shows dominant peaks at 346 nm (excitation 270 nm) due to 5d → 4f transition. Efficient energy transfer occurs from Ce(3+) → Dy(3+) ions. Dy(3+) emission at 485 nm and 576 nm is due to (4)  F9/2 → (6) H15/2 and (4)  F9/2 → (6) H13/2 transitions of Dy(3+) ion respectively. The TL glow curves of NaMgSO4 Cl:Ce and Ce,Dy have been recorded for various concentrations at a heating rate of 2 °C/s irradiated by γ-rays at a dose rate of 0.995 kGy/h for 1 Gy, which peaks at about 241 °C and 247-312 °C respectively. Further, in changing the concentration level, the general structure of the intensity is found to increase. The main property of this phosphor is its sensitivity even for low concentrations of rare earth ions and low γ-ray dose. There is still scope for higher doses of γ-radiation. The phosphor presented may be used as a lamp phosphor as well as for TL studies.

  9. Ba2Mg(BO3)2:Ce3+,Eu2+,Na+: A potential single-phased two colour borate phosphor for white light-emitting diodes

    Institute of Scientific and Technical Information of China (English)

    PAN Zaifa; XU Juan; ZHU Chengjing; LIU Wenhan; WANG Lili

    2012-01-01

    A two colour phosphor Ba2Mg(BO3)2:Ce3+,Eu2+,Na+ was synthesized using solid-state reaction method.Luminescence of Ba2Mg(BO3)2:Ce3+,Eu2+,Na+ showed 416 and 618 nm emission bands attributed to Ce3+ and Eu2+ emission,respectively.Energy transfer occurred from Ce3+ to Eu2+ through a significant overlap of Eu2+ excitation spectrum with Ce3+ emission spectrum in Ba2Mg(BO3)2.They also showed that under the excitation of UV radiation,bluish or yellowish white light was generated by coupling a broad blue emission band and a red emission band.By combining with green phosphor,Ba2Mg(BO3):Ce3+,Eu2+,Na+ phosphor showed potential application for white light-emitting diodes (LEDs).

  10. The Poisoning Effect of Na Doping over Mn-Ce/TiO2 Catalyst for Low-Temperature Selective Catalytic Reduction of NO by NH3

    Directory of Open Access Journals (Sweden)

    Liu Yang

    2014-01-01

    Full Text Available Sodium carbonate (Na2CO3, sodium nitrate (NaNO3, and sodium chloride (NaCl were chosen as the precursors to prepare the Na salts deposited Mn-Ce/TiO2 catalysts through an impregnation method. The influence of Na on the performance of the Mn-Ce/TiO2 catalyst for low-temperature selective catalytic reduction of NOx by NH3 was investigated. Experimental results showed that Na salts had negative effects on the activity of Mn-Ce/TiO2 and the precursors of Na salts also affected the catalytic activity. The precursor Na2CO3 had a greater impact on the catalytic activity, while NaNO3 had minimal effect. The characterization results indicated that the significant changes in physical and chemical properties of Mn-Ce/TiO2 were observed after Na was doped on the catalysts. The significant decreases in surface areas and NH3 adsorption amounts were observed after Na was doped on the catalysts, which could be considered as the main reasons for the deactivation of Na deposited Mn-Ce/TiO2.

  11. Ce and Eu activated Na2Zn5(PO4)4, a new promising novel phosphor

    Indian Academy of Sciences (India)

    K N Shinde; S J Dhoble; Animesh Kumar

    2011-07-01

    A new efficient phosphor, Eu2+/Eu3+ and Ce3+ activated Na2Zn5(PO4)4 has been synthesized by solid-state reaction technique at high temperature. X-ray powder diffraction analysis confirmed the formation of Na2Zn5(PO4)4 host lattice. Scanning electron microscopy indicated that the microstructure of the phosphor consisted of irregular fine grains with a size of about 0.5–2 m. Photoluminescence excitation spectrum measurements of Ce3+ activated Na2Zn5(PO4)4 show that the phosphor can be efficiently excited by UV-Vis light from 280 to 310 nm to realize emission in the visible (blue) range due to the 5–4 transition of Ce3+ ions which is applicable for scintillation purpose, whereas Eu2+/Eu3+ activated Na2Zn5(PO4)4 phosphor emits blue, green and red emission spectrum shows at 487 nm, 546 nm with a dominant peak at 611 nm respectively, due to Eu2+/Eu3+ ions which is promising candidate for solid state lighting. Therefore, newly synthesised, by low cost and easy technique prepared, novel phosphors may be useful as RGB phosphor for solid state lighting application.

  12. Energy resolution of LaBr3:Ce in a phoswich configuration with CsI:Na and NaI:Tl scintillator crystals

    Science.gov (United States)

    Hull, G.; Genolini, B.; Josselin, M.; Matea, I.; Peyré, J.; Pouthas, J.; Zerguerras, T.

    2012-12-01

    We studied the performances of the LaBr3:Ce scintillator when optically coupled to NaI:Tl and CsI:Na in a Phoswich detector for the R&D phase of the gamma ray calorimeter PARIS (Photon Array for the studies with Radioactive Ion and Stable beams). This detector has the purpose to measure γ-energies in a wide range (100 keV-40 MeV), and it will be used principally as a part of the SPIRAL2 instrumentation at GANIL. In this communication we report on the study of the light yield and energy resolution for gamma detection realized by coupling the phoswiches with various photomultiplier tubes, providing different characteristics. We were interested in investigating the possible degradation of the scintillation light produced by the LaBr3:Ce due to the presence of NaI:Tl/CsI:Na crystals, before being detected on the photocathode. For this purpose we realized all the measurements employing a standard ADC and QDC read-out system leading the possibility to perform a gate-based event selection. In this study we measured an energy resolution of 4.6% with an uncollimated 137Cs source for a 50.8×50.8×50.8 mm3 LaBr3:Ce coupled to a 50.8×50.8×152.4 mm3 NaI:Tl. This value is 30% bigger than the energy resolution measured for a 50.8×50.8×101.6 mm3 stand-alone LaBr3:Ce but still in the specifications for the PARIS collaboration physics list.

  13. Ultrafine Nanocrystalline CeO2@C-Containing NaAlH4 with Fast Kinetics and Good Reversibility for Hydrogen Storage.

    Science.gov (United States)

    Zhang, Xin; Liu, Yongfeng; Wang, Ke; Li, You; Gao, Mingxia; Pan, Hongge

    2015-12-21

    A nanocrystalline CeO2@C-containing NaAlH4 composite is successfully synthesized in situ by hydrogenating a NaH-Al mixture doped with CeO2@C. Compared with NaAlH4 , the as-prepared CeO2@C-containing NaAlH4 composite, with a minor amount of excess Al, exhibits significantly improved hydrogen storage properties. The dehydrogenation onset temperature of the hydrogenated [NaH-Al-7 wt % CeO2@C]-0.04Al sample is 77 °C lower than that of the pristine sample because of a reduced kinetic barrier. More importantly, the dehydrogenated sample absorbs ∼4.7 wt % hydrogen within 35 min at 100°C and 10 MPa of hydrogen. Compositional and structural analyses reveal that CeO2 is converted to CeH2 during ball milling and that the newly formed CeH2 works with the excess of Al to synergistically improve the hydrogen storage properties of NaAlH4. Our findings will aid in the rational design of novel catalyst-doped complex hydride systems with low operating temperatures, fast kinetics, and long-term cyclability.

  14. Efficient sensitization of Eu2+/Mn2+ emissions by Ce3+ doping in NaMgPO4 host under UV excitation

    Science.gov (United States)

    Zheng, Zhang; Wanjun, Tang

    2016-03-01

    A series of Ce3+/Eu2+/Mn2+-tridoped NaMgPO4 phosphors were synthesized using the combustion-assisted synthesis method. The luminescence properties and energy transfer from Ce3+/Eu2+ to Mn2+ in NaMgPO4 host have been studied. Co-doping Ce3+/Mn2+ is proved to be an ineffective approach to enhance the red emission of Mn2+, while effective energy transfer from Eu2+ to Mn2+ occurs in NaMgPO4:Eu2+,Mn2+ due to good spectrum overlap between the emission band of NaMgPO4:Eu2+ and the excitation band of NaMgPO4:Eu2+,Mn2+. NaMgPO4:Eu2+,Mn2+ phosphor shows a blue emission centered at 442 and a red emission peaking at 635 nm, which could be ascribed to the allowed 5 d-4 f transition of Eu2+ ions and the 4T1(4G)-6A1(6S) transition of Mn2+ ions, respectively. Co-doping Ce3+ ions can greatly enhance both the emission intensities of Eu2+ and Mn2+ ions, which is attributed to an efficient Ce3+ → Eu2+ → Mn2+ energy transfer and an increase in the number of luminescent centers (Eu2+) on Ce doping.

  15. Synergism of Rare Earth Ce(III) Ion with Cysteine against Corrosion of P110 Carbon Steel in 3% NaCl Solutions

    Science.gov (United States)

    Liu, Xia; Yang, Jianshu; Liu, Yongping; Ji, Xiangyun; Lu, Ying; Yuan, Yizhi

    The synergism of CeCl3 (Ce) with cysteine (Cys) on the corrosion of P110 carbon steel in 3% NaCl solutions was investigated by electrochemical methods and surface analysis. The results showed that CeCl3 and cysteine do little to inhibit the corrosion of carbon steel, but the combination of CeCl3 with cysteine has obvious synergistic effect on the corrosion of carbon steel and the corrosion inhibition efficiency was improved significantly. The potentiodynamic polarization curves indicated that the mixture of CeCl3 and cysteine acts as a cathodic inhibitor. Scanning electron microscope (SEM) and Infrared (IR) reflection spectra showed the synergistic inhibition effect was formed by the complexes between rare earth Ce(III) ion and amino acid.

  16. Dielectric and piezoelectric properties of (Li, Ce) modified NaBi5Ti5O18composite ceramics

    Institute of Scientific and Technical Information of China (English)

    MA Lei; ZHAO Kun; LI Jixia; WU Qi; ZHAO Minglei; WANG Chunlei

    2009-01-01

    Nominal (Li0.5Ce0.5)x(Na0.5Bi0.5)(1-x)Na0.5Bi4.5Ti5O18 composite ceramics were fabricated using conventional solid-state reaction method. The coexistence of bismuth layer-structured phase and perovskite phase was determined in these ceramics using XRD technique. At room temperature, the x=0.11 sample showed the largest piezoelectric constant, d33, of about 26.5 pC/N and the largest electromechanical coupling factor, kt, of about 30%. Even after annealing at 500 ℃, the value of d33 was still about 19 pC/N, in x=0.08-0.11 samples. Moreover, these composite ceramics showed low temperature coefficients of dielectric constant and high electrical resistivity in the temperature region of 450-550 ℃. These results indicated that (Li, Ce) modified NaBi5Ti5O18 composite ceramics were promising piezoelectric materials for high-temperature applications.

  17. Structural, optical and EPR studies of Cr{sup 3+} doped Na{sub 3}Ce(PO{sub 4}){sub 2} orthophosphate

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska, P.; Matraszek, A. [Faculty of Chemistry and Food Technology, Wrocław University of Economics, Komandorska 118/120, 53-345 Wrocław (Poland); Macalik, L. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland); Kaczmarek, S.M., E-mail: skaczmarek@zut.edu.pl [West Pomeranian University of Technology, Institute of Physics, Al. Piastów 48, 70-311 Szczecin (Poland); Skibiński, T. [West Pomeranian University of Technology, Institute of Physics, Al. Piastów 48, 70-311 Szczecin (Poland); Hermanowicz, K.; Ptak, M.; Lisiecki, R.; Ryba-Romanowski, W. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland); Szczygieł, I. [Faculty of Chemistry and Food Technology, Wrocław University of Economics, Komandorska 118/120, 53-345 Wrocław (Poland); Hanuza, J. [Faculty of Chemistry and Food Technology, Wrocław University of Economics, Komandorska 118/120, 53-345 Wrocław (Poland); Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland)

    2014-09-01

    Highlights: • Cr{sup 3+}doped Na{sub 3}Ce(PO{sub 4}){sub 2} crystalline powders were synthesized by Pechini method. • The optical and magnetic properties of Na{sub 3}Ce(PO{sub 4}){sub 2}:Cr{sup 3+} were investigated. • Cr{sup 3+} ions in the distorted octahedral environment replace Ce{sup 3+} in the unit cell. • EPR and magnetic data reveal two different kinds of chromium centers appear. - Abstract: Micro-crystalline powders of Na{sub 3}Ce(PO{sub 4}){sub 2} orthophosphate doped with Cr{sup 3+} ions were synthesized and characterised by means of X-ray diffraction, IR and Raman, electron absorption, magnetic and EPR studies. The emission and excitation spectra and fluorescence decay time were recorded in the temperature range 70–293 K. The spectroscopic properties of Ce{sup 3+} and Cr{sup 3+} ions in the studied materials were discussed in terms of the structure and local symmetry of the optical ions. These data were compared to those obtained for NaCe(PO{sub 3}){sub 4} metaphosphate.

  18. Loparite, a rare-earth ore (Ce, Na, Sr, Ca)(Ti, Nb, Ta, Fe+3)O3

    Science.gov (United States)

    Hedrick, James B.; Sinha, Shyama P.; Kosynkin, Valery D.

    1997-01-01

    The mineral loparite (Ce, NA, Sr, Ca)(Ti, Nb, Ta, Fe+3)O3 is the principal ore of the light-group rare-earth elements (LREE) in Russia. The complex oxide has a perovskite (ABO3) structure with coupled substitutions, polymorphism, defect chemistry and a tendency to become metamict. The A site generally contains weakly bonded, easily exchanged cations of the LREE, Na and Ca. The B site generally contains smaller, highly charged cations of Ti, Nb or Fe+3. Mine production is from Russia's Kola Peninsula. Ore is beneficiated to produce a 95% loparite concentrate containing 30% rare-earth oxides. Loparite concentrate is refined by either a chlorination process or acid decomposition process to recover rare-earths, titanium, niobium and tantalum. Rare-earths are separated by solvent extraction and selective precipitation/dissolution. The concentrate is processed at plants in Russia, Estonia and Kazakstan.

  19. Combined effects Na and SO2 in flue gas on Mn-Ce/TiO2 catalyst for low temperature selective catalytic reduction of NO by NH3 simulated by Na2SO4 doping

    Science.gov (United States)

    Zhou, Aiyi; Yu, Danqing; Yang, Liu; Sheng, Zhongyi

    2016-08-01

    A series of Mn-Ce/TiO2 catalysts were synthesized through an impregnation method and used for low temperature selective catalytic reduction (SCR) of NOx with ammonia (NH3). Na2SO4 was added into the catalyst to simulate the combined effects of alkali metal and SO2 in the flue gas. Experimental results showed that Na2SO4 had strong and fluctuant influence on the activity of Mn-Ce/TiO2, because the effect of Na2SO4 included pore occlusion and sulfation effect simultaneously. When Na2SO4 loading content increased from 0 to 1 wt.%, the SCR activities of Na2SO4-doped catalysts decreased greatly. With further increasing amount of Na2SO4, however, the catalytic activity increased gradually. XRD results showed that Na2SO4 doping could induce the crystallization of MnOx phases, which were also confirmed by TEM and SEM results. BET results showed that the surface areas decreased and a new bimodal mesoporous structure formed gradually with the increasing amount of Na2SO4. XPS results indicated that part of Ce4+ and Mn3+ were transferred to Ce3+ and Mn4+ due to the sulfation after Na2SO4 deposition on the surface of the catalysts. When the doped amounts of Na2SO4 increased, NH3-TPD results showed that the Lewis acid sites decreased and the Brønsted acid sites of Mn-Ce/TiO2 increased quickly, which could be considered as another reason for the observed changes in the catalytic activity. The decreased Mn and Ce atomic concentration, the changes of their oxidative states, and the variation in acidic properties on the surface of Na2SO4-doped catalysts could be the reasons for the fluctuant changes of the catalytic activity.

  20. PL and TL study of NaMgSO{sub 4}F:X (X=Dy or Ce) fluoride phosphor by SSD method

    Energy Technology Data Exchange (ETDEWEB)

    Choubey, S.R. [Department of Physics, SRMCEW Nandanvan, Nagpur 440009 (India); Gedam, S.C., E-mail: gedam_sc@rediffmail.com [K.Z.S. Science College, Kalmeshwar, Nagpur 441501 (India); Dhoble, S.J. [Department of Physics, RTM Nagpur University, Nagpur 440033 (India)

    2013-10-15

    Dy{sup 3+} and Ce{sup 3+} emission in NaMg(SO{sub 4})F phosphor prepared by the solid state diffusion (SSD) method is reported in this paper. The synthesized phosphors are studied for their photoluminescence (PL) and thermoluminescence (TL) characteristics. The emission spectra of Dy{sup 3+} show dominant peaks at 473 nm and 572 nm for an excitation of 274 nm due to the {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2} and {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} transitions respectively, while the emission spectra of Ce{sup 3+} peak at 345 nm for an excitation of 254 nm due to the 5d→4f transition of Ce{sup 3+}. In this host very low concentration of cerium is used. In NaMg(SO{sub 4})F:Dy{sup 3+} a single peak is observed at the temperature of 170 °C and in NaMg(SO{sub 4})F:Ce it is located at 172 °C when they are exposed to γ-rays for 5 Gy at the rate of 0.995 kGyh{sup −1}. NaMg(SO{sub 4})F:Dy is more sensitive whereas, NaMg(SO{sub 4})F:Ce less sensitive as compared to standard CaSO{sub 4}:Dy. NaMg(SO{sub 4})F:Dy phosphor may be useful for TLD application. -- Highlights: • Dy{sup 3+} and Ce{sup 3+} emission in NaMg(SO{sub 4})F phosphor prepared by the solid state diffusion method. • Photoluminescence and thermoluminescence characteristics have been studied in NaMg(SO{sub 4})F:Ce and Dy. • The NaMg(SO{sub 4})F:Ce and Dy can be prepared by multisynthesis methods.

  1. Synthesis and photoluminescence characterization of Ce3+ and Dy3+ activated ALa(WO4)2(A = Na and Li) novel phosphors

    Indian Academy of Sciences (India)

    Parag Nimishe; S J Dhoble

    2011-08-01

    In this paper, we report the synthesis of Ce3+ and Dy3+ activated alkali lanthanide tungstates, ALa(WO4)2(where A = Na and Li), prepared by solid state reaction method. The prepared phosphors were characterized by X-ray diffraction and photoluminescence techniques. The NaLa(WO4)2:Dy3+ and LiLa(WO4)2:Dy3+ phosphors show two emission peaks at around 574 and 486 nm (exc = 354 nm). NaLa(WO4)2:Ce3+ and LiLa(WO4)2:Ce3+ show two emission peaks at around 378 and 425 nm (exc = 350 nm). Excitation wavelengths of Ce3+ and Dy3+ activated alkali lanthanide tungstates are in near UV region i.e. Hg free excitation. These characterizations of phosphors are applicable for solid state lighting. Accordingly, Ce3+ and Dy3+ activated NaLa(WO4)2 and LiLa(WO4)2 may be the promising materials for solid state lighting applications.

  2. Blue-green tunable color of Ce3+/Tb3+ coactivated NaBa3La3Si6O20 phosphor via energy transfer

    Science.gov (United States)

    Jia, Zhen; Xia, Mingjun

    2016-01-01

    A series of color tunable phosphors NaBa3La3Si6O20:Ce3+, Tb3+ were synthesized via the high-temperature solid-state method. NaBa3La3Si6O20 crystallizes in noncentrosymmetric space group Ama2 with the cell parameters of a = 14.9226(4) Å, b = 24.5215(5) Å and c = 5.6241(2) Å by the Rietveld refinement method. The Ce3+ ions doped NaBa3La3Si6O20 phosphors have a strong absorption band from 260 to 360 nm and show near ultraviolet emission light centered at 378 nm. The Ce3+ and Tb3+ ions coactivated phosphors exhibit color tunable emission light from deep blue to green by adjusting the concentration of the Tb3+ ions. An energy transfer of Ce3+ → Tb3+ investigated by the photoluminescence properties and lifetime decay, is demonstrated to be dipole–quadrupole interaction. These results indicate the NaBa3La3Si6O20:Ce3+, Tb3+ phosphors can be considered as potential candidates for blue-green components for white light emitting diodes. PMID:27628111

  3. Structural, optical and EPR studies of NaCe(PO{sub 3}){sub 4} metaphosphate doped with Cr{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska, P.; Matraszek, A. [Wrocław University of Economics, Faculty of Chemistry and Food Technology, Komandorska 118/120, 53-345 Wrocław (Poland); Kaczmarek, S.M.; Fuks, H.; Skibiński, T. [West Pomeranian University of Technology, Institute of Physics, Al. Piastów 48, 70-311 Szczecin (Poland); Hermanowicz, K.; Ptak, M. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland); Szczygieł, I. [Wrocław University of Economics, Faculty of Chemistry and Food Technology, Komandorska 118/120, 53-345 Wrocław (Poland); Macalik, L., E-mail: L.Macalik@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland); Lisiecki, R.; Ryba-Romanowski, W. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland); Hanuza, J. [Wrocław University of Economics, Faculty of Chemistry and Food Technology, Komandorska 118/120, 53-345 Wrocław (Poland); Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland)

    2014-02-15

    The undoped and Cr{sup 3+}-doped NaCe(PO{sub 3}){sub 4} metaphosphates were synthesized by the modified Pechini method and obtained as the crystalline powders. They were characterized by means of X-ray diffraction, vibrational and optical spectroscopy to clarify the structure and mechanism of Cr{sup 3+} emission in NaCe(PO{sub 3}){sub 4}. This phosphor crystallizes in the monoclinic P12{sub 1}/n1 structure with an infinite (PO{sub 3}){sub n} chain. The Cr{sup 3+} ions can substitute the C{sub 1} symmetry site occupied by cerium ions. They can also occupy the tunnels formed in the anionic layer. Spectroscopic properties of the Cr{sup 3+} and Ce{sup 3+} ions were discussed in terms of structure of the studied crystalline powders. IR and Raman data confirm the predicted structure and indicate C{sub 1} site symmetry of the Cr{sup 3+} active ions. The Cr{sup 3+} ions appear in the distorted octahedral environment of the weak crystal field. Optical studies were confirmed by EPR results carried out in the temperature range of 4–293 K. In addition, the magnetic measurements were performed up to 305 K. The Cr{sup 3+} ions reveal negligible ferromagnetic interactions while the Ce{sup 3+} ions change their magnetic interactions from slightly antiferromagnetic to significantly ferromagnetic above 20 K. -- Highlights: • NaCe(PO{sub 3}){sub 4}:Cr{sup 3+} crystalline powders were synthesized by the modified Pechini method. • The optical and magnetic properties of the NaCe(PO{sub 3}){sub 4}:Cr{sup 3+} crystalline powders were investigated. • Cr{sup 3+} ions replacing Ce{sup 3+} ions in the unit cell are in the distorted octahedral environment. • Cr{sup 3+} ions reveal ferromagnetic interactions, that strength depends on temperature.

  4. Luminescence and energy transfer of color-tunable Na6Ca3Si6O18:Ce3+,Tb3+ phosphors for WLED

    Science.gov (United States)

    Xu, Huawei; Liu, Qunxing; Huang, Linyi; He, Zhiyuan; Wang, Shen; Jiang, Chunxu; Peng, Qi

    2017-03-01

    A series of Ce3+, Tb3+ co-doped Na6Ca3Si6O18 phosphors have been synthesized by traditional solid state reaction. The emission spectra of the Na6Ca3Si6O18:Ce3+,Tb3+ phosphors show a blue broad band at 450 nm of the Ce3+ and a green line peaking at 550 nm. Energy transfer from Ce3+ to Tb3+ ions has been investigated. Results indicate that the color of these phosphors changes from blue to green by adjusting the ratio of Ce3+ to Tb3+. In addition, the mechanism of the energy transfer from the Ce3+ to Tb3+ ions is demonstrated to be a dipole-quadrupole mechanism. The energy transfer efficiency as well as the critical distance is also estimated. By optimizing the Tb3+ concentration, the absolute PL quantum yield as high as 43% can be achieved. The results show that this phosphor has potential applications as a single-phased phosphor for UV white-light LEDs.

  5. CeO2/NaF吸附剂的制备及其对MoF6的吸附性能研究%Preparation of adsorbent CeO2/NaF and its adsorption performance for MoF6

    Institute of Scientific and Technical Information of China (English)

    李洒洒; 程治强; 李杨娟; 龙德武; 龚昱; 窦强; 吴明红; 李晴暖

    2015-01-01

    Background: The fluoride volatility process has been developed to recover uranium from spent nuclear fuel. And the fluoride adsorption technique is usually applied in the purification and collection of UF6 during the fluoride volatility process.Purpose: This study aims to investigate the characteristics and sorption performance of a novel sorbent CeO2/NaF synthesized by doping NaF with CeF3.Methods: With polymer sodium carboxymethyl cellulose (CMC) as a binder and pore-forming agent, CeF3 and NaFwas mixed according to a mass ratio of 4:9:62, and then water were added (the ratio of CMC to water is 1:6). The porous CeO2/NaF adsorbent particles were prepared by a mixing, molding and sintering process. The characteristics and adsorption performance of the adsorbent particles were analyzed and characterized.Results: Specific surface area of CeO2/NaF was (0.84±0.04)m2·g−1, which was twice of NaF sorbent made under the same process. Porosity was 42.2%, which was larger than that of NaF sorbent. The initial adsorption rate of MoF6 on CeO2/NaF was much higher than that of NaF sorbent. The temperature zone for desorption of MoF6 from CeO2/NaF ranged from 150°C to 300°C, while there were two desorption zones for desorption of MoF6 from NaF sorbent, which varied from 100°C to 300°C and 350°C to 400°C, respectively. This phenomenon showed that CeO2 might stabilize Mo6+in MoF6. Conclusion: The physical properties of NaF could be changed by doping with CeO2, and its adsorption performance was also improved.%将作为粘结剂和造孔剂的高分子羧甲基纤维素钠(Carboxymethylcellulose, CMC)、CeF3和NaF按4:9:62的质量比例混合,再加一定量的水(CMC与水的比为1:6),通过混捏、成形和烧结等程序制得了一种新型的CeO2/NaF吸附剂颗粒。通过研究CeO2的掺杂对NaF吸附剂表观性质和吸附性能的影响发现:CeO2/NaF吸附剂的比表面积为(0.84±0.04) m2·g−1,是相同条件下制得的 NaF 吸附剂

  6. Enhanced 1G 4 emission in NaLaF 4: Pr 3+, Yb 3+ and charge transfer in NaLaF 4: Ce 3+, Yb 3+ studied by fourier transform luminescence spectroscopy

    Science.gov (United States)

    van der Kolk, E.; Ten Kate, O. M.; Wiegman, J. W.; Biner, D.; Krämer, K. W.

    2011-05-01

    A high resolution luminescence study of NaLaF 4: 1%Pr 3+, 5%Yb 3+ and NaLaF 4: 1%Ce 3+, 5%Yb 3+ in the UV to NIR spectral range using a InGaAs detector and a fourier transform interferometer is reported. Although the Pr 3+( 3P 0 → 1G 4), Yb 3+( 2F 7/2 → 2F 5/2) energy transfer step takes place, significant Pr 3+1G 4 emission around 993, 1330 and 1850 nm is observed. No experimental proof for the second energy transfer step in the down-conversion process between Pr 3+ and Yb 3+ can be given. In the case of NaLaF 4: Ce 3+, Yb 3+ it is concluded that the observed Yb 3+ emission upon Ce 3+ 5d excitation is the result of a charge transfer process instead of down-conversion.

  7. Corrosion behavior of as-cast Mg-8Li-3Al+ xCe alloy in 3.5wt% NaCl solution

    Science.gov (United States)

    Manivannan, S.; Dinesh, P.; Mahemaa, R.; MariyaPillai, Nandhakumaran; Kumaresh Babu, S. P.; Sundarrajan, Srinivasan

    2016-10-01

    Mg-8Li-3Al+ xCe alloys ( x = 0.5wt%, 1.0wt%, and 1.5wt%) were prepared through a casting route in an electric resistance furnace under a controlled atmosphere. The cast alloys were characterized by X-ray diffraction, optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The corrosion behavior of the as-cast Mg-8Li-3Al+ xCe alloys were studied under salt spray tests in 3.5wt% NaCl solution at 35°C, in accordance with standard ASTM B-117, in conjunction with potentiodynamic polarization (PDP) tests. The results show that the addition of Ce to Mg-8Li-3Al (LA83) alloy results in the formation of Al2Ce intermetallic phase, refines both the α-Mg phase and the Mg17Al12 intermetallic phase, and then increases the microhardness of the alloys. The results of PDP and salt spray tests reveal that an increase in Ce content to 1.5wt% decreases the corrosion rate. The best corrosion resistance is observed for the LA83 alloy sample with 1.0wt% Ce.

  8. 立方相NaYF4∶Ce3+材料的合成及上转换发光性能%Hydrothermal Synthesis and Up-conversion Luminescent Properties of NaYF4 ∶ Ce3+ Cubic Phase

    Institute of Scientific and Technical Information of China (English)

    陈喜蓉; 陈早明; 胡德远

    2012-01-01

    以氟化钠、硝酸钇、硝酸铈为原料,采用水热法和共沉淀法合成棒状NaYF4∶Ce3+材料,利用XRD、SEM、红外光谱、荧光光谱分析仪对其结构和发光性能进行表征.结果表明,制备样品均为立方相结构,表面含有以化学吸附方式存在的EDTA分子.经水热法制备样品的上转换发射发射出波长在404.5nm和436nm处的蓝光,以及波长在520.5nm和539nm处的绿光.%NaYF4 : Ce3+ luminescent materials were synthesized by hydrothermal method and copreciptation using sodium fluoride, yttrium nitrate, cerous nitrate as raw materials. The obtained samples were characterized by X-ray powder diffraction(XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectra and luminescence spectrum. The XRD resulting of NaYF4 : Ce3+ materials are mainly cubic phase and the FT-IR spectra prove the presence of EDTA at the surface of crystals. Under continuous-wave excitation of 980nm laser, the NaYF4 : Ce3+ samples prepared by hydrothermal exhibit strong up conversion light. The blue emission from Ce3+ at 404. 5nm and at 436nm, the green emission at 520. 5nm and at 539nm, indicative of the great potential for the NaYF4 : Ce3+ samples to be used on solar cell.

  9. Photoluminescence characterization and energy transfer of NaBa1-x-yPO4:xCe3+, yTb3+ phosphors

    Institute of Scientific and Technical Information of China (English)

    DOU Xihua; ZHAO Weiren; SONG Enhai; DENG Linlin; FANG Xiabing; MIN Huachu

    2012-01-01

    A series of NaBal-x- yPO4:xCe3+,yTb3+ phosphors were synthesized by solid-state reaction method.The crystal structure,photoluminescence emission and excitation spectra and decay times of the phosphors were carefully investigated.The results revealed that an efficient energy transfer occurred from Ce3+ to Tb3+ ions in NaBaPO4 host by means of dipole-dipole ineractions and the critical distance of the energy transfer was about 0.638 nm.Moreover,the phosphor emitted strong green emission under UV excitation,indicating that the phosphors are potentially useful as a highly efficient,green-emitting phosphor.

  10. Influence of Shell Formation on Morphological Structure, Optical and Emission Intensity on Aqueous Dispersible NaYF4:Ce/Tb Nanoparticles.

    Science.gov (United States)

    Ansari, Anees A; Parchur, A K; Kumar, B; Rai, S B

    2016-07-01

    A highly water-dispersible NaYF4:Ce/Tb (core), NaYF4:Ce/Tb@NaYF4(core/shell) and NaYF4:Ce/Tb@NaYF4@SiO2 (core/shell/SiO2) nanoparticles (NPs) were synthesized via a general synthesis approach. The growth of an inert NaYF4 and silica shell (~14 nm) around the core-NPs resulted in an increase of the average size of the nanopaticles as well as broadening of their size distribution. The optical band-gap energy slightly decreases after shell formation due to the increase the crystalline size. To optimize the influence of shell formation a comparative analysis of photoluminescence properties (excitation, emission, and luminescence decay time) of the core, core/shell, and core/shell/SiO2 NPs were measured. The emission intensity was significantly enhanced after inert shell formation around the surface of the core NPs. The Commission International de l'Eclairage chromaticity coordinates of the emission spectrum of core, core/shell, core/shell/SiO2 NPs lie closest to the standard green color emission at 545 nm. By quantitative spectroscopic measurements of surface-modified core-NPs, it was suggested that encapsulation with inert and silica layers was found to be effective in retaining both luminescence intensity and dispersibility in aqueous environment. Considering the high aqueous dispersion and enhanced luminescence efficiency of the core-NPs make them an ideal luminescent material for luminescence bioimaging and optical biosensors.

  11. A "Pedagogia" da Feira Livre de SÃo Bento: narrativas, saberes e prÃticas educativas na cidade de Cascavel - CE

    OpenAIRE

    Francisca Eliana Santos da Silva

    2014-01-01

    Neste estudo, buscamos compreender as prÃticas educativas e os saberes presentes na feira livre de SÃo Bento, localizada na cidade de Cascavel-CE a qual dista de Fortaleza 64 km. Para a realizaÃÃo dessa pesquisa, escolhemos como suporte teÃrico BrandÃo (2005); Durkheim (2007); Burke (2003); Huberman (1976) e Certeau (1998). Optamos pelo enfoque qualitativo e utilizamos a pesquisa bibliogrÃfica como suporte no esclarecimento do tema investigado. Usamos tambÃm o estudo de caso que proporcionou ...

  12. Optical characterization and the energy level scheme for NaYP{sub 2}O{sub 7}:Ln{sup 3+} (Ln=Ce, Sm, Eu, Tb, Yb)

    Energy Technology Data Exchange (ETDEWEB)

    Novais, S.M.V., E-mail: suellenvaleriano@yahoo.com.br [Laboratory of Advanced Ceramic Materials, Physics Department, Federal University of Sergipe, 49.100-000, São Cristóvão, SE (Brazil); Dobrowolska, A.; Bos, A.J.J.; Dorenbos, P. [Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Macedo, Z.S. [Laboratory of Advanced Ceramic Materials, Physics Department, Federal University of Sergipe, 49.100-000, São Cristóvão, SE (Brazil)

    2014-04-15

    Vacuum ultra-violet spectroscopy at low temperature was performed with undoped and Ln{sup 3+}-doped NaYP{sub 2}O{sub 7} (Ln=Ce, Sm, Eu, Tb and Yb). The emission observed from the NaYP{sub 2}O{sub 7} host was attributed to self-trapped exciton (STE) recombination. Dopant ions were well incorporated and responsible for characteristic luminescent emission in the doped samples. From excitation curves, 4f–5d transitions were identified for Ce{sup 3+}, Sm{sup 3+} and Tb{sup 3+} and charge transfer processes were noticed for Eu{sup 3+}, Sm{sup 3+} and Yb{sup 3+}. The experimental data obtained was used to determine the positions of the energy levels of divalent and trivalent lanthanides relative to the valence and conduction band of this compound. The experimentally derived levels are in good agreement with model predictions. The results are valuable to provide a better understanding on the performance of NaYP{sub 2}O{sub 7} and related diphosphates as luminescent materials. -- Highlights: • NaYP{sub 2}O{sub 7} polycrystalline samples were produced via the sol–gel method. • VUV excitation and emission spectra were successfully studied. • Luminescent properties were discussed. • The experimentally derived energy levels are in good agreement with model predictions.

  13. Clinical evaluation of pixellated NaI:Tl and continuous LaBr 3:Ce, compact scintillation cameras for breast tumors imaging

    Science.gov (United States)

    Pani, R.; Pellegrini, R.; Betti, M.; De Vincentis, G.; Cinti, M. N.; Bennati, P.; Vittorini, F.; Casali, V.; Mattioli, M.; Orsolini Cencelli, V.; Navarria, F.; Bollini, D.; Moschini, G.; Iurlaro, G.; Montani, L.; de Notaristefani, F.

    2007-02-01

    The principal limiting factor in the clinical acceptance of scintimammography is certainly its low sensitivity for cancers sized scintillation camera based on Lanthanum tri-Bromide Cerium-doped crystal (LaBr 3:Ce), that demonstrating superior imaging performances with respect to the dedicated scintillation γ-camera that was previously developed. The proposed detector consists of continuous LaBr 3:Ce scintillator crystal coupled to a Hamamatsu H8500 Flat Panel PMT. One centimeter thick crystal has been chosen to increase crystal detection efficiency. In this paper, we propose a comparison and evaluation between lanthanum γ-camera and a Multi PSPMT camera, NaI(Tl) discrete pixel based, previously developed under "IMI" Italian project for technological transfer of INFN. A phantom study has been developed to test both the cameras before introducing them in clinical trials. High resolution scans produced by LaBr 3:Ce camera showed higher tumor contrast with a detailed imaging of uptake area than pixellated NaI(Tl) dedicated camera. Furthermore, with the lanthanum camera, the Signal-to-Noise Ratio ( SNR) value was increased for a lesion as small as 5 mm, with a consequent strong improvement in detectability.

  14. CF4 decomposition over solid ternary mixture NaF-Si-MO (MO =La2O3, CeO2, Pr6O11, Nd2O3, Y2O3)

    Institute of Scientific and Technical Information of China (English)

    Yanfei Pan; Xianjun Niu; Yanan Wang; Xiufeng Xu

    2012-01-01

    A solid ternary mixture consisting of NaF,silicon and one metal oxide such as La2O3,CeO2,Pr6O11,Nd2O3,and Y2O3 was prepared and used as de-fluorinated reagent for CF4 decomposition.The results show that 90% conversion of CF4 can be reached initially over NaF-Si-La2O3,NaF-Si-CeO2,NaF-Si-Nd2O3,and NaF-Si-Y2O3 at 850 ℃.The fresh and used reagents were characterized using XRD and XPS techniques.It was found that the active components of NaF and metal oxides in NaF-Si-CeO2,NaF-Si-Pr6O11,NaF-Si-Nd2O3,and NaF-Si-Y2O3 were transformed into inert phases of mixed metal fluorides and silicates,respectively,resulting in an ineffective utilization of these de-fluorinated reagents,whereas no inert phases from NaF and La2O3 can be observed in the used NaF-Si-La2O3,indicating the NaF-Si-La2O3 reagent could be utilized more efficiently than the other reagents in CF4 decomposition.

  15. Synthesis of NaLuF4:Er3+, Yb3+, Ce3+ nanoparticles and study of photoluminescent properties in C - band

    Directory of Open Access Journals (Sweden)

    Khaydukov K.V.

    2017-01-01

    Full Text Available The novel core@shell nanocrystals β-NaLuF4@NaLuF4 co-doped with rare-earth ions Er3+, Yb3+, Ce3+ have been synthesized. The nano-particles indicate the intensive lines of anti-Stokes luminescence in the telecommunication С - band of spectrum when pumped at 970-980 nm. The nanoparticles have been characterized by transmission electron microscopy and spectrofluorimetry. The nanoparticles have a size 40-80 nm and possess the intensive photo-luminescence 73 nm bandwidth centered around 1530 nm. The photo-luminescence kinetics of β-NaLuF4: Er3+/ Yb3+/ Ce3+ has been studied in IR range of spectrum. We have demonstrated that doping with cerium ions prevents serial stepwise excitation of erbium ions. Consequently, the lifetime of transition in erbium 4I13/2→4I15/2 has risen up to 6.9 ms. Intensity of 1530 nm line in Er3+ ions excited at 980 nm has been increased up to 6 times. Therefore, the nanoparticles are applicable to fabrication of compact waveguide amplifiers for C - band.

  16. Structure and photoluminescence properties of Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} phosphors for solid-state lighting application

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Dawei; Yang, Hui; Yang, Guanhui; Shi, Jianxin, E-mail: cessjx@mail.sysu.edu.cn; Wu, Mingmei, E-mail: ceswmm@mail.sysu.edu.cn; Su, Qiang

    2014-05-01

    Novel phosphors of Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+} and Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} were synthesized by a solid-state process and characterized with X-ray diffraction, photoluminescence (PL), PL excitation (PLE), and fluorescence decay time. The relationship between the observed Ce{sup 3+} emission properties and the crystal structure of Na{sub 2}Y{sub 2}B{sub 2}O{sub 7} is built and the result shows that Ce{sup 3+} ions occupy two non-equivalent Y{sup 3+} sites in the host. The codoping of Tb{sup 3+} in Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+} can tune the emitting colour from blue to green and increase the luminescence quantum efficiency to 75.2% by the energy transfer of Ce{sup 3+}→Tb{sup 3+}. The energy transfer processes of Ce{sup 3+}–Ce{sup 3+} and Ce{sup 3+}–Tb{sup 3+} are analysed and determined to be electric dipole–dipole and dipole–quadrupole, respectively. The broad PLE spectra of Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+} and Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} are well matched with the emission from near UV LED chips, which indicates that they are promising blue and green phosphors for phosphor-converted white LEDs. - Graphical abstract: Colour-tunable phosphors Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} with optimal quantum yield of 75.2% are synthesized and the phosphors can be served as n-UV pumped materials for LEDs. - Highlights: • Green phosphor Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} with quantum efficiency of 75.2% for n-UV application is synthesized. • The site occupation of Ce{sup 3+} in Na{sub 2}Y{sub 2}B{sub 2}O{sub 7} is investigated with the crystal structure and photoluminescence spectra. • The energy transfer of Ce{sup 3+}–Ce{sup 3+} and Ce{sup 3+}–Tb{sup 3+}, which is responsible to the tunable emitting colour of the phosphor, is demonstrated and the mechanism is studied.

  17. Synthesis and crystal structure determination of some polymetallic oxalates of U{sup IV}, Na, Ln{sup III} (Ln = Ce and Nd)

    Energy Technology Data Exchange (ETDEWEB)

    Chapelet-Arab, B.; Grandjean, S.; Nowogrocki, G.; Abraham, F

    2004-07-01

    In the course of investigations of oxalic coprecipitation of uranium(IV) and cerium (III) an oxalate containing also sodium ions was isolated. Its structure was determined by single crystal X-ray diffraction and led to the formula (U{sub 1}Ce{sub 1})Na{sub 3}(C{sub 2}O{sub 4}){sub 5} 10.4H{sub 2}O. Astonishingly, the two heavy metallic ions occupy the same crystallographic site, the alkaline ion assuring the charge neutrality. This behaviour has also been evidenced on two oxalates of uranium(IV) and neodymium(III) exhibiting various ratio U(IV)/Nd(III). Though (U{sub 1.44}Nd{sub 0.56})Na{sub 2.4}(C{sub 2}O{sub 4}){sub 5} 10H{sub 2}O and (U{sub 1}Ce{sub 1})Na{sub 3}(C{sub 2}O{sub 4}){sub 5} 10.4H{sub 2}O present different ratio U(IV)/Ln(III), their crystallographic structures are similar. In these three-dimensional structural arrangements, uranium(IV) and lanthanide(III) are surrounded by five bidentate oxalate units and water molecules lie in the middle of (U,Ln){sub 3}(C{sub 2}O{sub 4}){sub 6} honeycomb hexagonal six-membered rings. Although the synthesis conditions are close, (U{sub 1}Nd{sub 1})Na(C{sub 2}O{sub 4}){sub 4} 8H{sub 2}O is built from an unlike coordination polyhedra which is constituted of four bidentate oxalate ligands and one water molecule.

  18. Experimental constraints on the relative stabilities of the two systems monazite-(Ce) - allanite-(Ce) - fluorapatite and xenotime-(Y) - (Y,HREE)-rich epidote - (Y,HREE)-rich fluorapatite, in high Ca and Na-Ca environments under P-T conditions of 200-1000 MPa and 450-750 °C

    Science.gov (United States)

    Budzyń, Bartosz; Harlov, Daniel E.; Kozub-Budzyń, Gabriela A.; Majka, Jarosław

    2016-09-01

    The relative stabilities of phases within the two systems monazite-(Ce) - fluorapatite - allanite-(Ce) and xenotime-(Y) - (Y,HREE)-rich fluorapatite - (Y,HREE)-rich epidote have been tested experimentally as a function of pressure and temperature in systems roughly replicating granitic to pelitic composition with high and moderate bulk CaO/Na2O ratios over a wide range of P-T conditions from 200 to 1000 MPa and 450 to 750 °C via four sets of experiments. These included (1) monazite-(Ce), labradorite, sanidine, biotite, muscovite, SiO2, CaF2, and 2 M Ca(OH)2; (2) monazite-(Ce), albite, sanidine, biotite, muscovite, SiO2, CaF2, Na2Si2O5, and H2O; (3) xenotime-(Y), labradorite, sanidine, biotite, muscovite, garnet, SiO2, CaF2, and 2 M Ca(OH)2; and (4) xenotime-(Y), albite, sanidine, biotite, muscovite, garnet, SiO2, CaF2, Na2Si2O5, and H2O. Monazite-(Ce) breakdown was documented in experimental sets (1) and (2). In experimental set (1), the Ca high activity (estimated bulk CaO/Na2O ratio of 13.3) promoted the formation of REE-rich epidote, allanite-(Ce), REE-rich fluorapatite, and fluorcalciobritholite at the expense of monazite-(Ce). In contrast, a bulk CaO/Na2O ratio of ~1.0 in runs in set (2) prevented the formation of REE-rich epidote and allanite-(Ce). The reacted monazite-(Ce) was partially replaced by REE-rich fluorapatite-fluorcalciobritholite in all runs, REE-rich steacyite in experiments at 450 °C, 200-1000 MPa, and 550 °C, 200-600 MPa, and minor cheralite in runs at 650-750 °C, 200-1000 MPa. The experimental results support previous natural observations and thermodynamic modeling of phase equilibria, which demonstrate that an increased CaO bulk content expands the stability field of allanite-(Ce) relative to monazite-(Ce) at higher temperatures indicating that the relative stabilities of monazite-(Ce) and allanite-(Ce) depend on the bulk CaO/Na2O ratio. The experiments also provide new insights into the re-equilibration of monazite-(Ce) via fluid

  19. Characterization of PARIS LaBr$_3$(Ce)-NaI(Tl) phoswich detectors upto $E_\\gamma$ $\\sim$ 22 MeV

    CERN Document Server

    Ghosh, C; Pillay, R G; K., Anoop; Dokania, N; Pal, Sanjoy; Pose, M S; Mishra, G; Rout, P C; Kumar, Suresh; Pandit, Deepak; Mondal, Debasish; Pal, Surajit; Banerjee, S R; Napiorkowski, Paweł J; Dorvaux, Oliver; Kihel, S; Mathieu, C; Maj, A

    2016-01-01

    In order to understand the performance of the PARIS (Photon Array for the studies with Radioactive Ion and Stable beams) detector, detailed characterization of two individual phoswich (LaBr$_3$(Ce)-NaI(Tl)) elements has been carried out. The detector response is investigated over a wide range of $E_{\\gamma}$ = 0.6 to 22.6 MeV using radioactive sources and employing $^{11}B(p,\\gamma)$ reaction at $E_p$ = 163 keV and $E_p$ = 7.2 MeV. The linearity of energy response of the LaBr$_3$(Ce) detector is tested upto 22.6 MeV using three different voltage dividers. The data acquisition system using CAEN digitizers is set up and optimized to get the best energy and time resolution. The energy resolution of $\\sim$ 2.1% at $E_\\gamma$ = 22.6~MeV is measured for configuration giving best linearity upto high energy. Time resolution of the phoswich detector is measured with $^{60}$Co source after implementing CFD algorithm for the digitized pulses and is found to be excellent (FWHM $\\sim$ 315~ps). In order to study the effect...

  20. Návrh WiFi sítě na Úřadu práce v Prostějově

    OpenAIRE

    Slunský, Tomáš

    2008-01-01

    Tato bakalářská práce analyzuje současný stav síťové infrastruktury ve zvolené organizaci. Na základě této analýzy je provedena úvaha nad možností rozšíření této sítě o bezdrátovou WiFi síť včetně výběru vhodné technologie a navržení struktury bezdrátové sítě včetně implementace tohoto řešení do organizace. This bachelor’s thesis analysis the present situation of the net infrastructure in the chosen organisation. Based on this analysis it is considered possibility to extend this net by the...

  1. Investigation of the hydrothermal crystallisation of the perovskite solid solution NaCe{sub 1−x}La{sub x}Ti{sub 2}O{sub 6} and its defect chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Harunsani, Mohammad H. [Department of Chemistry, University of Warwick, Coventry CV4 7AL (United Kingdom); Woodward, David I. [Department of Physics, University of Warwick, Coventry CV4 7Al (United Kingdom); Peel, Martin D.; Ashbrook, Sharon E. [School of Chemistry, and EaStCHEM University of St. Andrews, North Haugh, St. Andrews, KY16 9ST (United Kingdom); Walton, Richard I., E-mail: r.i.walton@warwick.ac.uk [Department of Chemistry, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2013-11-15

    Perovskites of nominal composition NaCe{sub 1−x}La{sub x}Ti{sub 2}O{sub 6} (0≤x≤1) crystallise directly under hydrothermal conditions at 240 °C. Raman spectroscopy shows distortion from the ideal cubic structure and Rietveld analysis of powder X-ray and neutron diffraction reveals that the materials represent a continuous series in rhombohedral space group R3-bar c. Ce L{sub III}-edge X-ray absorption near edge structure spectroscopy shows that while the majority of cerium is present as Ce{sup 3+} there is evidence for Ce{sup 4+}. The paramagnetic Ce{sup 3+} affects the chemical shift and line width of {sup 23}Na MAS NMR spectra, which also show with no evidence for A-site ordering. {sup 2}H MAS NMR of samples prepared in D{sub 2}O shows the inclusion of deuterium, which IR spectroscopy shows is most likely to be as D{sub 2}O. The deuterium content is highest for the cerium-rich materials, consistent with oxidation of some cerium to Ce{sup 4+} to provide charge balance of A-site water. - Graphical abstract: A multi-element A-site perovskite crystallises directly from aqueous, basic solutions at 240 °C; while the paramagnetic effect of Ce{sup 3+} on the {sup 23}Na NMR shows a homogeneous solid-solution, the incorporation of A-site water is also found from {sup 2}H NMR and IR, with oxidation of some cerium to charge balance proved by XANES spectroscopy. Display Omitted - Highlights: • Direct hydrothermal synthesis allows crystallisation of a perovskite solid-solution. • XANES spectroscopy shows some oxidation of Ce{sup 3+} to Ce{sup 4+}. • The paramagnetism of Ce{sup 3+} shifts and broadens the {sup 23}Na solid-state NMR. • The perovskite materials incorporate water as an A-site defect.

  2. Luminescence and thermoluminescence of Sr sub 2 B sub 5 O sub 9 X:Ce sup 3 sup + ,A sup + (X = Cl, Br, A = Na sup + , K sup +) phosphors

    CERN Document Server

    Sidorenko, A V; Dorenbos, P; Rodnyi, P A; Eijk, C W E; Berezovskaya, I V; Dotsenko, V P

    2003-01-01

    The luminescence properties of Ce sup 3 sup + activated strontium haloborates with and without K sup + or Na sup + co-doping have been studied under optical and x-ray excitation. Three types of Ce sup 3 sup + emission centre have been found as the result of different methods of charge compensation in non-co-doped samples. In the co-doped compounds only one type of Ce sup 3 sup + emission centre has been observed. The influence of Ce sup 3 sup + concentration, anion type and co-doping ion on thermoluminescence (TL) has been analysed. The TL glow curves of all the studied materials contain two peaks. The emission corresponding to the low temperature peak is associated with charge uncompensated Ce sup 3 sup + centres in non-co-doped compounds. The emission of the high temperature peak represents the superposition of both charge compensated and uncompensated Ce sup 3 sup + centres. The emission corresponding to both TL peaks in co-doped samples originates from one type of Ce sup 3 sup + centre.

  3. Condições higiênico-sanitárias na comercialização de pescados em Sobral − CE | Hygienic-sanitary conditions in fish trading in Sobral − CE

    Directory of Open Access Journals (Sweden)

    Mauro Vinicius Dutra Girão

    2015-11-01

    Full Text Available Este trabalho objetiva avaliar as condições higiênico-sanitárias dos comércios de pescado particulares do município de Sobral − CE, através da análise visual e utilização de um checklist, baseado na RDC no 216. As informações foram coletadas através da observação da rotina de trabalho dos estabelecimentos registrados na Vigilância Sanitária Municipal durante inspeções mensais em um período de três meses. Para cada critério contido no checklist, foi realizada uma média das conformidades e não conformidades e quantificação do percentual de acertos de cada. Os estabelecimentos inspecionados encontram-se em condições de funcionamento que oferecem riscos moderados de contaminação dos pescados. Dentre os fatores de risco de contaminação encontram-se a Edificação, devido à presença de insetos, que são potenciais vetores mecânicos de microorganismos, a Higienização de utensílios, devido as não conformidades quanto à disposição dos equipamentos para o adequado fluxo dos trabalhadores, infiltrações, telas, ralos sinfonados, caixas de gorduras, luminárias, instalações elétricas e sanitárias, e Manipuladores, que falavam sobre o alimento, manuseavam dinheiro, não utilizavam cabelos presos e utilizavam adornos. Mesmo observando um despreparo das pessoas envolvidas na atividade, observa-se uma tendência à adequação à legislação sanitária em prol da qualidade do alimento. =============================================== The aim of this study was to evaluate the sanitary conditions of the fish markets in the city of Sobral, CE, using visual analysis and a checklist based on the RDC 216. The information was collected over a period of three months during monthly inspections in fish market establishments registered with the Brazilian Health Surveillance town. We calculated the percentage of compliance/non-compliance for each checklist item. Each of the inspected establishments showed signs of moderate

  4. RELAÇÃO ENTRE IDADE E CAPACIDADE FUNCIONAL DE IDOSAS RESIDENTES EM INSTITUIÇÕES DE LONGA PERMANÊNCIA NA CIDADE DE FORTALEZA/CE

    Directory of Open Access Journals (Sweden)

    Darling Kescia Araújo Peixoto Braga

    2014-12-01

    Full Text Available Introdução: O envelhecimento gera desgastes fisiológicos próprios. O sistema de valores socioculturais ocidentais e a atual configuração dos arranjos familiares associados aumenta a institucionalização de idosos, que pela fragilidade podem ter déficits na execução das atividades básicas de vida diária (ABVD's e cognição. Objetivo: Avaliar o desempenho nas ABVD, considerando a faixa etária de mulheres idosas residentes em duas Instituições de Longa Permanência para Idosos (ILPI´s na cidade de Fortaleza/CE. Métodos: Estudo seccional, realizado no período de Outubro a Dezembro de 2013 através de um censo com 24 idosas residentes em duas ILPI's. A coleta de dados foi realizada em duas etapas: formulário com caracterização da amostra e o questionário de ABVD de Barthel. Resultados: A amostra possui idade média de 80,04 anos (± 7,91; mín, = 65,0 e máx. = 90,0, eram solteira (66,6%, com baixa escolaridade (33,3% analfabetas e 33,3% com primário completo, procedentes do interior do Estado (58,3% e residiam na instituição há menos de cinco anos (58,3%. O Índice de Barthel revelou que a maioria (75% eram independentes para a realização das ABVDs, sem influenciada da faixa etária. Conclusão: As idosas residentes nas ILPI apresentam independência funcional nas ABVD e sem influência da idade.

  5. Prevalência de asma em adolescentes na cidade de Fortaleza, CE Prevalence of asthma among adolescents in the city of Fortaleza, Brazil

    Directory of Open Access Journals (Sweden)

    Maria de Fátima Gomes de Luna

    2009-11-01

    Full Text Available OBJETIVO: Avaliar a prevalência de asma em adolescentes (13-14 anos na cidade de Fortaleza, CE. MÉTODOS: Estudo transversal utilizando o questionário do International Study of Asthma and Allergies in Childhood e envolvendo 3.015 adolescentes de escolas públicas e privadas entre 2006 e 2007. RESULTADOS: As prevalências de "sibilos alguma vez na vida", "sibilos nos últimos doze meses" (asma ativa e "asma alguma vez na vida" (asma diagnosticada foram, respectivamente, 44,1%, 22,6% e 11,6%. As prevalências de "sibilos alguma vez na vida" (p = 0,001, "1-3 crises de sibilos nos últimos 12 meses" (p = 0,001; asma ativa (p = 0,002; "sono interrompido por sibilos menos que uma vez por semana" (p OBJECTIVE: To determine the prevalence of asthma among adolescents (13-14 years of age in the city of Fortaleza, Brazil. METHODS: This was a cross-sectional study involving 3,015 adolescents at public and private schools between 2006 and 2007. The participants completed the International Study of Asthma and Allergies in Childhood questionnaire. RESULTS: The prevalences of "wheezing ever", "wheezing within the last 12 months" (active asthma and "asthma ever" (physician-diagnosed asthma were 44.1%, 22.6% and 11.6%, respectively. The prevalences of "wheezing ever" (p = 0.001, "1-3 wheezing attacks within the last 12 months" (p = 0.001, active asthma (p = 0.002, "sleep disturbed due to wheezing less than one night per week" (p < 0.001 and "dry cough at night" (p < 0.001 were higher among girls. Private school students presented higher prevalences of "wheezing ever", active asthma, "1-3 wheezing attacks within the last 12 months", "4-12 wheezing attacks within the last 12 months" and physician-diagnosed asthma (p < 0.001 for all, as well as of "exercise-induced wheezing" (p = 0.032. CONCLUSIONS: The prevalence of asthma and asthma-related symptoms in students aged 13-14 years in the city of Fortaleza, Brazil, was high, predominantly among girls and private

  6. Study of the nitric acid influence on the production of Ce O{sub 2} with high specific surface area; Estudo da influencia do acido nitrico na obtencao de CeO{sub 2} com alta area superficial especifica

    Energy Technology Data Exchange (ETDEWEB)

    Albanez, Nelma Kunrath; Bressiani, Jose Carlos [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1996-12-31

    The cerium oxide (Ce O{sub 2}) main characteristics for use as catalyst in an exhaust gases purification system are: high specific surface area (approximately 30 m{sup 2}/g after calcination at 800 deg C/ 2 hs), and thermal stability. The Ce O{sub 2} powders obtained by conventional route, i.e., precipitation, and submitted high temperature (800 deg C) heat treatments, showed low specific surface area. In this work nitric acid effects on the Ce O{sub 2} surface area values were investigated. The variables studied were nitric acid concentration, humidity content in the raw material, re pulp after leaching, addition of hydrogen peroxide (H{sub 2} O{sub 2}) and starting material specific surface area. By this process, it was possible to obtain powders with specific surface area larger than 40 m{sup 2}/g, after treatment at 800 deg C during two hours. (author) 8 refs., 3 figs., 1 tab.

  7. Combustion synthesis and luminescence investigation of Na{sub 3}Al{sub 2}(PO{sub 4}){sub 3}:RE (RE = Ce{sup 3+}, Eu{sup 3+} and Mn{sup 2+}) phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Nagpure, I.M., E-mail: indrajitnagpure@yahoo.co.i [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, Free State 9300 (South Africa); Shinde, K.N. [Department of Physics, RTM Nagpur University, Nagpur 440033 (India); Kumar, Vinay; Ntwaeaborwa, O.M. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, Free State 9300 (South Africa); Dhoble, S.J. [Department of Physics, RTM Nagpur University, Nagpur 440033 (India); Swart, H.C., E-mail: swarthc@ufs.ac.z [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, Free State 9300 (South Africa)

    2010-03-04

    Rare-earth (Ce{sup 3+}or Eu{sup 3+}) or alkali-earth metal (Mn{sup 2+}) doped Na{sub 3}Al{sub 2}(PO{sub 4}){sub 3} phosphor powder were prepared by a combustion method. Regardless of the dopants, the Na{sub 3}Al{sub 2}(PO{sub 4}){sub 3} was shown to crystallize as hexagonal (rhombohedral) NASICON phase with spheroidal micron sized particles based upon X-ray diffraction (XRD) and scanning electron microscopy (SEM) data. As confirmed by thermogravimetric (TGA) and differential thermal analysis (DTA) data, the powders were stable at high temperatures up to 900 {sup o}C. A broad UV emission (with maximum at 328 nm) associated with the 5d {yields} 4f transition of Ce{sup 3+} was observed from Na{sub 3}Al{sub 2}(PO{sub 4}){sub 3}:Ce{sup 3+} while Mn{sup 2+} and Eu{sup 3+} doping showed stable green and red photoluminescence emission at 515 and 615 nm, respectively. For different molar concentrations of rare-earth/alkali-earth metal dopants, the PL intensity was shown to increase to a certain concentration before quenching occurred at higher concentrations. The structure and optical properties of these phosphors were evaluated.

  8. Combined effects Na and SO{sub 2} in flue gas on Mn-Ce/TiO{sub 2} catalyst for low temperature selective catalytic reduction of NO by NH{sub 3} simulated by Na{sub 2}SO{sub 4} doping

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Aiyi [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing 210023 (China); Yu, Danqing [School of Chemical Engineering and Technology, Wuhan University of Science and Technology, Wuhan 430081 (China); Yang, Liu [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing 210023 (China); Sheng, Zhongyi, E-mail: 09377@njnu.edu.cn [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing 210023 (China)

    2016-08-15

    Highlights: • Sodium sulfate (Na{sub 2}SO{sub 4}) was deposited on Mn-Ce/TiO{sub 2} catalyst to simulate the co-existing of sodium and SO{sub 2} in the flue gas. • Na{sub 2}SO{sub 4} had strong and fluctuant influence on Mn-Ce/TiO{sub 2} catalyst’s performance in SCR of NOx with NH{sub 3}, due to the combined effect of the deactivation of sodium salts and the enhanced performance of ceria with surface sulfation. • The changes of the surface chemical species and acid sites on the Na{sub 2}SO{sub 4} deposited catalysts could be considered as the main reasons for the fluctuation changes with the catalytic activity. - Abstract: A series of Mn-Ce/TiO{sub 2} catalysts were synthesized through an impregnation method and used for low temperature selective catalytic reduction (SCR) of NOx with ammonia (NH{sub 3}). Na{sub 2}SO{sub 4} was added into the catalyst to simulate the combined effects of alkali metal and SO{sub 2} in the flue gas. Experimental results showed that Na{sub 2}SO{sub 4} had strong and fluctuant influence on the activity of Mn-Ce/TiO{sub 2}, because the effect of Na{sub 2}SO{sub 4} included pore occlusion and sulfation effect simultaneously. When Na{sub 2}SO{sub 4} loading content increased from 0 to 1 wt.%, the SCR activities of Na{sub 2}SO{sub 4}-doped catalysts decreased greatly. With further increasing amount of Na{sub 2}SO{sub 4}, however, the catalytic activity increased gradually. XRD results showed that Na{sub 2}SO{sub 4} doping could induce the crystallization of MnOx phases, which were also confirmed by TEM and SEM results. BET results showed that the surface areas decreased and a new bimodal mesoporous structure formed gradually with the increasing amount of Na{sub 2}SO{sub 4}. XPS results indicated that part of Ce{sup 4+} and Mn{sup 3+} were transferred to Ce{sup 3+} and Mn{sup 4+} due to the sulfation after Na{sub 2}SO{sub 4} deposition on the surface of the catalysts. When the doped amounts of Na{sub 2}SO{sub 4} increased, NH{sub 3

  9. Enhancement of electrical properties of Na0.5 Bi0.5 TiO3 powders by Ce doping and Ce penetration%Ce对Nao.5Bi0.5Ti03粉体的掺杂和扩渗改性研究

    Institute of Scientific and Technical Information of China (English)

    郝素娥; 付东升; 米南; 李佳龙; 强亮生

    2012-01-01

    For improving the electrical conductivity of Na0.5 Bi0.5 TiO3 (NBT) powders, the pure NBT powders were produced by sol-gel method and modified by Ce liquid doping and Ce gaseous penetration. The effect of modification on the constitution,structure and electrical properties of Ce-modified Na0.5 Bi0. 5 TiO3 powders was studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), impedance analyzer and resistance meter. The results showed that the addition of Ce helped to reduce the resistivity of Na0.5 Bio. 5 TiO3 powders, and the penetration method broughtl the lower resistivity than the doping method. The resistivity of Ce-modified Na0.sBio.sTiO3 powders penetrated at 600 ℃ was the lowest,which was decreased to 2.39 × 101 Ω · m from 3.71 × 106 Ω · m. The doping method made the dielectric constant of Na0.5 Bi0.5 TiO3 powders decreased, but the penetration method had the reverse effect. The Ce-doped Na0.5 Bi0.5 TiO3 powders had homogeneous finest particle size, and the particle size of the Ce-penetrated Na0. 5 Bio. 5 TiO3 powders was progressed with the penetration temperature increasing. The doping method did not change the main crystalline phases. But the new phases of Bi, Bi2Ti2OT, Na2Ti9019 and Na2Ti6013 were detected in the Ce-penetrated Na0.5Bi0.5TiO3 powders.%摘要:为改善Nao,Bi0.5Ti03材料的电性能,采用溶胶一凝胶法制备了Nao,Bi0.5TiO3粉体,通过液相Ce掺杂和气相Ce扩渗两种方法,对Na0,Bi0.5TiO3粉体进行了改性,采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、阻抗分析仪和电阻仪对改性前后Nao,Bi0.5TiO3粉体的组成、结构和电性能的变化进行了研究.结果表明:Ce元素的添加有助于Na0.5Bi0.5TiO3粉体电阻率的降低,而扩渗改性使电阻率的降低更为显著,经600℃扩渗的Na0.5Bi0.5TiO3粉体的电阻率由3.71×106Ω·m降至2.39×101Ω·m;稀土Ce掺杂使Nao.5Bi0.5TiO3的介电常数减小,而Ce扩渗使Nao

  10. Preparation of Na{sub 4}UO{sub 2}(CO{sub 3}){sub 3} in presence of Ce-141. I, Influence of the post-reaction time in the concentration of anion species of Ce-141; Preparacion del Na{sub 4}UO{sub 2}(CO{sub 3}){sub 3} en presencia de Ce-141. I, Influencia del tiempo de post-reaccion en la concentracion de especies anionicas de Ce-141

    Energy Technology Data Exchange (ETDEWEB)

    Lopez M, B.E.; Rodriguez S, A.; Iturbe G, J.L

    1991-10-15

    An effective condition to minimize the presence of Ce-141, in the final product of recovery like hexa hydrated uranyl nitrate has been obtained. It is considered to this condition like a pre purification stage in the recovery process of the non-fissioned residual uranium in the fission production of Mo-99. (Author)

  11. AÃÃo antidumping: produÃÃo de camarÃo em cativeiro e desenvolvimento regional na microrregiÃo do litoral de Aracati â CE

    OpenAIRE

    Antonio Kaminski Alves

    2012-01-01

    Esta pesquisa tem como proposta analisar os impactos causados pela aÃÃo antidumping imposta aos produtores de camarÃo brasileiros pela indÃstria de pesca norte-americana, assim como seus efeitos sobre o desenvolvimento econÃmico para a MicrorregiÃo Litoral de Aracati â CE, no perÃodo de 2003 a 2010. Trata-se de pesquisa de carÃter exploratÃrio, conforme pressupostos teÃrico-metodolÃgicos apresentados por LÃdke e Andrà (1986). Na pesquisa, buscou-se evidenciar fatos da realidade por meio de am...

  12. Energy and resolution calibration of NaI(Tl) and LaBr{sub 3}(Ce) scintillators and validation of an EGS5 Monte Carlo user code for efficiency calculations

    Energy Technology Data Exchange (ETDEWEB)

    Casanovas, R., E-mail: ramon.casanovas@urv.cat [Unitat de Fisica Medica, Facultat de Medicina i Ciencies de la Salut, Universitat Rovira i Virgili, ES-43201 Reus (Tarragona) (Spain); Morant, J.J. [Servei de Proteccio Radiologica, Facultat de Medicina i Ciencies de la Salut, Universitat Rovira i Virgili, ES-43201 Reus (Tarragona) (Spain); Salvado, M. [Unitat de Fisica Medica, Facultat de Medicina i Ciencies de la Salut, Universitat Rovira i Virgili, ES-43201 Reus (Tarragona) (Spain)

    2012-05-21

    The radiation detectors yield the optimal performance if they are accurately calibrated. This paper presents the energy, resolution and efficiency calibrations for two scintillation detectors, NaI(Tl) and LaBr{sub 3}(Ce). For the two former calibrations, several fitting functions were tested. To perform the efficiency calculations, a Monte Carlo user code for the EGS5 code system was developed with several important implementations. The correct performance of the simulations was validated by comparing the simulated spectra with the experimental spectra and reproducing a number of efficiency and activity calculations. - Highlights: Black-Right-Pointing-Pointer NaI(Tl) and LaBr{sub 3}(Ce) scintillation detectors are used for gamma-ray spectrometry. Black-Right-Pointing-Pointer Energy, resolution and efficiency calibrations are discussed for both detectors. Black-Right-Pointing-Pointer For the two former calibrations, several fitting functions are tested. Black-Right-Pointing-Pointer A Monte Carlo user code for EGS5 was developed for the efficiency calculations. Black-Right-Pointing-Pointer The code was validated reproducing some efficiency and activity calculations.

  13. cDNA library Table: ce-- [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available ce-- NA ce-- C202 x J201 compound eyes mixture of fifth instar larval stage to pupa...l stage mixed pBluescript SK- EcoR1 for 5' Xho1for 3' sequenced from T3 primer (5' -> 3') BP117205-BP118782 ce--[number] ...

  14. Uma princesa tombada às margens do Rio Salgado: dinâmica urbana e ações preservacionistas na cidade de Icó, CE

    OpenAIRE

    Nascimento, José Clewton do

    2003-01-01

    p. 115 - 130 O artigo versa sobre a análise dos discursos preservacionistas e seu rebatimento nas ações de intervenção no núcleo urbano de Icó / CE cidade tombada pelo IPHAN como Patrimônio Nacional em 1997 pautados numa pretensa valorização do Lugar Sertão, transformando-o em atrativo turístico. Dentro dos parâmetros seguidos, a característica competitiva do lugar passa a se sobressair perante a sua representatividade cultural, visto que esta última por si só não se ...

  15. Preparation of Na{sub 4}UO{sub 2}(CO{sub 3}){sub 3} in presence of Ce-141. II, Treatment of uranium decontamination; Preparacion del Na{sub 4}UO{sub 2}(CO{sub 3}){sub 3} en presencia de Ce-141. II, Tratamiento de descontaminacion de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Lopez M, B.E.; Rodriguez S, A

    1992-02-15

    It was settled down that the coexistence of chemical species structurally different of cerium, is a consequence of the preparation time; whose practical application, for the purification of the uranium, it can constitute the technological aspect but important in the ion exchange process, to separate the Ce-141 from the uranium. (Author)

  16. Implantação do Programa Saúde na escola em Fortaleza-CE: atuação de equipe da Estratégia Saúde da Família Implantación del Programa de Salud Escolar en Fortaleza-CE: desempeño de equipo de la Estrategia Salud de la Familia School Health Program implementation in Fortaleza-CE: performance of the Family Health Strategy staff

    Directory of Open Access Journals (Sweden)

    Lindelvania Matias de Santiago

    2012-12-01

    Full Text Available Este trabalho relata a experiência da implantação do Programa Saúde na Escola (PSE por uma equipe da Estratégia Saúde da Família (ESF em uma escola pública em Fortaleza-CE. As atividades desenvolvidas incluíram seminário de implantação do PSE com os docentes e integrantes da ESF, oficinas com os estudantes, avaliação clinica e odontológica dos adolescentes e entrega de Cadernetas de Saúde do Adolescente. A implantação do PSE permitiu aos profissionais de saúde a percepção do seu papel social de educador e possibilitou aos adolescentes maior contato com a equipe da ESF. A aproximação entre escola e ESF é fundamental para ajudar os adolescentes a transformarem a informação científica em comportamentos saudáveis.Este artículo relata la experiencia de implementación del Programa de Salud Escolar (PSE por un equipo de la Estrategia de Salud de la Familia (ESF en una escuela pública en Fortaleza-CE, Brasil. Las actividades incluyeron seminario de despliegue del PSE con los maestros y los miembros de la ESF, talleres con los estudiantes, la evaluación clínica y dental de los adolescentes y la entrega de folletos de Salud del Adolescente. La aplicación del PSE permitió a los profesionales de salud a darse cuenta de su papel social como educadores y permitió a los adolescentes un mayor contacto con el personal de la ESF. El acercamiento entre la escuela y el FSE es crucial para ayudar a los adolescentes a transformar el conocimiento científico en comportamientos saludables.This work reports the experience of implementation of the School Health Program (PSE by a team from the Family Health Strategy (FHS in a public school in Fortaleza-CE , Brazil. The activities included conference about the deployment of the PSE with teachers and members of the FHS, workshops with students, clinical and dental assessment for adolescents and delivery of Booklets of Adolescent Health. The implementation of the PSE allowed health

  17. Factors affecting heavy metals accumulation in potato tubers / Czynniki wpływające na akumulację metali ciężkich w bulwach ziemniaka

    Directory of Open Access Journals (Sweden)

    Musilova Janette

    2015-09-01

    Full Text Available Badano wpływ wybranych czynników agrochemicznych na akumulację metali ciężkich w bulwach ziemniaka. Gleby uprawne mogą być zanieczyszczone metalami ciężkimi. Pierwiastki, które występują w glebach w formach biodostępnych (mobilnych mogą zostać włączone do obiegu biologicznego, mając tym samym negatywny wpływ na jakość plonów i zdrowie konsumentów/ człowieka. W badanych glebach oznaczono całkowitą zawartość: Zn, Cu, Ni, Pb, Cd oraz udział tych pierwiastków w formach mobilnych. Spośród badanych pierwiastków najbardziej mobilnym metalem był ołów, którego zakres zawartości w formach mobilnych wynosił: 0,100-0,295 mg∙kg-1, przekraczając dopuszczalne wartości dla tego pierwiastka. Zawartość ołowiu w ziemniakach wynosiła: 0.244-0.855 mg∙kg-1 FM. Analiza statystyczna wykazała istotną korelację pomiędzy zawartością pierwiastków w formach mobilnych i ich zawartością w ziemniakach oraz między odczynem badanych gleb, a całkowitą zawartością ołowiu w ziemniakach. Nie zaobserwowano istotnej statystycznie korelacji pomiędzy zawartością próchnicy w glebach a zawartością ołowiu w ziemniakach

  18. Defect Scheelite-Type Lanthanoid(III Ortho-Oxomolybdates(VI Ln0.667[MoO4] (Ln = Ce, Pr, Nd, and Sm and Their Relationship to Zircon and the NaTl-Type Structure

    Directory of Open Access Journals (Sweden)

    Ingo Hartenbach

    2011-12-01

    Full Text Available The rare-earth metal(III ortho-oxomolybdates with the formula Ln0.667[MoO4] (Ln = Ce, Pr, Nd, and Sm and defect scheelite-type structure crystallize in the tetragonal space group I41/a (a = 533–525, c = 1183–1158 pm with four formula units per unit cell. The Ln3+ cations at Wyckoff position 4b exhibit a coordination sphere of eight oxygen atoms in the shape of a trigonal dodecahedron. The same site symmetry (.. is observed for the tetrahedral oxomolybdate(VI entities [MoO4]2–, since their central Mo6+ cation is situated at the 4a position. Due to this equal site multiplicity, the lanthanoid(III cations have to be statistically under-occupied to maintain electroneutrality, thus a defect scheelite structure emerges. The partial structure of both the Ln3+ cations and the [MoO4]2– anions (if shrunk to their centers of gravity can be best described as distorted diamond-like arrangements. Therefore, these two interpenetrating partial structures exhibit a similar setup as found in the zircon-type as well as in the NaTl-type structure.

  19. Implantação do Programa Saúde na escola em Fortaleza-CE: atuação de equipe da Estratégia Saúde da Família

    Directory of Open Access Journals (Sweden)

    Lindelvania Matias de Santiago

    2012-12-01

    Full Text Available Este trabalho relata a experiência da implantação do Programa Saúde na Escola (PSE por uma equipe da Estratégia Saúde da Família (ESF em uma escola pública em Fortaleza-CE. As atividades desenvolvidas incluíram seminário de implantação do PSE com os docentes e integrantes da ESF, oficinas com os estudantes, avaliação clinica e odontológica dos adolescentes e entrega de Cadernetas de Saúde do Adolescente. A implantação do PSE permitiu aos profissionais de saúde a percepção do seu papel social de educador e possibilitou aos adolescentes maior contato com a equipe da ESF. A aproximação entre escola e ESF é fundamental para ajudar os adolescentes a transformarem a informação científica em comportamentos saudáveis.

  20. Effect of oxidizing agents in CeO2 thin film formation.

    Science.gov (United States)

    Yadav, S. M.; Sartale, S. D.

    2012-06-01

    Cerium Oxide (CeO2) thin films have been prepared by oxidative soak method onto glass substrates using NaNO2 and NaBrO3 oxidizing agents. Because of different oxidation strength different crystallinity, morphology and optical properties of the CeO2 films have been observed. Furthermore it has been observed that crystalline, transparent and crack free CeO2 thin films can be obtained using NaNO2 oxidizing agent. On the other hand CeO2 thin films deposited by using NaBrO3 oxidizing agent are amorphous, less transparent and porous with large number of cracks.

  1. Estudo microestrutural do catalisador Ni/gama-Al2O3: efeito da adição de CeO2 na reforma do metano com dióxido de carbono Microstructural study of Ni/gamma-Al2O3 catalyst: addition effects of CeO2 on carbon dioxide reforming of methane

    Directory of Open Access Journals (Sweden)

    Antoninho Valentini

    2003-10-01

    Full Text Available The carbon dioxide reforming of methane was carried out over nickel catalysts supported on the gamma-Al2O3/CeO2 system prepared by wet impregnation. With the increase of the CeO2 weight in the catalyst, a higher stability was observed in the catalytic activity, together with an excellent resistance to carbon deposition and a better Ni dispersion. The catalysts were characterized by means of surface area measurements, TPR, H2 chemisorption, XRD, SEM, EDX, XPS and TEM. An interaction between Ni and CeO2 was observed to the Ni/CeO2 sample after activation in a H2 atmosphere above 300 ºC. Such behavior has a significantly influence on the catalytic activity.

  2. Natural perovskite: (CaII0.95 (1CeIII0.011 (2NaI0.010 (4(FeIII0.022 (2TiIV0.98 (1O3

    Directory of Open Access Journals (Sweden)

    Nelson G. Fernandes

    2008-09-01

    Full Text Available A natural sample of perovskite (calcium caesium sodium iron titanium oxide from the Tapira Alkaline Complex in southeastern Brazil was found by electron microprobe analysis to have the chemical formula (Ca2+0.95 (1Ce3+0.011 (2Na+0.010 (4(Fe3+0.022 (2Ti4+0.98 (1O2−3 and by IR spectroscopy to be an anhydrous mineral. Oxygen anions are arranged around Ti4+ in an almost perfect octahedron and around Ca2+ in a distorted 12-fold polyhedron.

  3. Study of the hyperfine magnetic field acting on Ce probes substituting for the rare earth and the magnetic ordering in intermetallic compounds RAg (R=rare earth) by first principles calculations; Estudo do campo hiperfino magnetico na sonda de Ce colocada nos compostos intermetalicos do tipo RAg (R=terra rara) e do ordenamento magnetico desses compostos usando calculos de primeiros principios

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Luciano Fabricio Dias

    2006-07-01

    In this work the magnetic hyperfine field acting on Ce atoms substituting the rare-earths in R Ag compounds (R = Gd e Nd) was studied by means of first-principles electronic structure calculations. The employed method was the Augmented Plane Waves plus local orbitals (APW+lo), embodied in the WIEN2k program, within the framework of the Density Functional Theory (DFT) and with the Generalized Gradient Approximation (GGA) for the exchange and correlation potential. The super-cell approach was utilized in order to simulate for the Ce atoms acting as impurities in the R Ag matrix. In order to improve for correlation effects within the 4f shells, a Hubbard term was added to the DFT Hamiltonian, within a procedure called GGA+U. It was found that the magnetic hyperfine field (MHF) generated by the Ce 4f electron is the main component of the total MHF and that the Ce 4f ground state level is probably a combination of the m{sub l} = -2 and m{sub l} = -1 sub-levels. In addition, the ground-state magnetic structure was determined for Ho Ag and Nd Ag by observing the behavior of the total energy as a function of the lattice volume for several possible magnetic ordering in these compounds, namely, ferromagnetic, and the (0,0,{pi}), ({pi},{pi},0) and (({pi},{pi},{pi}) types of anti-ferromagnetic ordering of rare-earth atoms. It was found that the ground-state magnetic structure is anti-ferromagnetic of type ({pi},{pi},0) for both, the Ho Ag and Nd Ag compounds. The energy difference of the ferromagnetic and antiferromagnetic ordering is very small in the case of the Nd Ag compound. (author)

  4. Challenges of CE

    NARCIS (Netherlands)

    Verhagen, Wim J.C.; Stjepandić, Josip; Wognum, Nel

    2015-01-01

    Despite a long pedigree and many positive reports on its use and benefits, concurrent engineering (CE) and its associated research (sub)domains still experience significant development. In this final chapter, a socio-technical framework is applied to classify and analyze challenges identified as

  5. CE-BEMS

    DEFF Research Database (Denmark)

    Mohamed, Nader; Lazarova-Molnar, Sanja; Al-Jaroodi, Jameela

    2016-01-01

    and costs savings in smart buildings significantly depend on the monitoring and control methods used in the installed BEMS. This paper proposes a Cloud-Enabled BEMS (CE-BEMS) for Smart Buildings. This system can utilize cloud computing to provide enhanced management mechanisms and features for energy...

  6. Oxygen vacancy and Ce{sup 3+} ion dependent magnetism of monocrystal CeO{sub 2} nanopoles synthesized by a facile hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Leini [School of Physics and Materials Science, Anhui University, Hefei 230039 (China); Anhui Key Laboratory of Information Materials and Devices, Anhui University, Hefei 230039 (China); Meng, Fanming, E-mail: mrmeng@ahu.edu.cn [School of Physics and Materials Science, Anhui University, Hefei 230039 (China); Anhui Key Laboratory of Information Materials and Devices, Anhui University, Hefei 230039 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China)

    2013-09-01

    Graphical abstract: - Highlights: • Monocrystal CeO{sub 2} nanopoles are synthesized by hydrothermal method. • Suitable reaction time is beneficial for the growth CeO{sub 2} nanopoles. • As-synthesized CeO{sub 2} nanopoles show excellent RTFM. • The RTFM can be attributed to the influences of oxygen vacancies and Ce{sup 3+} ions. - Abstract: Monocrystal CeO{sub 2} nanopoles of 15–25 nm in diameter and 300–900 nm or more in length were synthesized within 100 h using hydrothermal method with CeCl{sub 3}·7H{sub 2}O as cerium source, NaOH as mineralizer, and ethylenediamine as complexant. The results of XRD and SADE analysis indicate that the as-synthesized CeO{sub 2} samples have the fluorite structure. The band gaps of CeO{sub 2} samples are 0.08–0.38 eV smaller than that of bulk CeO{sub 2}. X-ray photoelectron spectroscopy shows that the concentration of Ce{sup 3+} is higher than 20% for CeO{sub 2} samples. All the as-synthesized CeO{sub 2} samples exhibit the room temperature ferromagnetism (RTFM), and the saturation magnetization (M{sub s}) gradually increases with the increase of E{sub g} up to 2.92 eV and then decreases with E{sub g} increasing more. The highest M{sub s} of 0.167 emu/g is obtained from the CeO{sub 2} nanopoles synthesized within 100 h. The RTFM mechanism of CeO{sub 2} nanopoles has been proposed which can be mainly attributed to the influence of oxygen vacancies and Ce{sup 3+} ions.

  7. Epitaxial Cubic Ce2O3 Films via Ce-CeO2 Interfacial Reaction.

    Science.gov (United States)

    Stetsovych, Vitalii; Pagliuca, Federico; Dvořák, Filip; Duchoň, Tomáš; Vorokhta, Mykhailo; Aulická, Marie; Lachnitt, Jan; Schernich, Stefan; Matolínová, Iva; Veltruská, Kateřina; Skála, Tomáš; Mazur, Daniel; Mysliveček, Josef; Libuda, Jörg; Matolín, Vladimír

    2013-03-21

    Thin films of reduced ceria supported on metals are often applied as substrates in model studies of the chemical reactivity of ceria based catalysts. Of special interest are the properties of oxygen vacancies in ceria. However, thin films of ceria prepared by established methods become increasingly disordered as the concentration of vacancies increases. Here, we propose an alternative method for preparing ordered reduced ceria films based on the physical vapor deposition and interfacial reaction of Ce with CeO2 films. The method yields bulk-truncated layers of cubic c-Ce2O3. Compared to CeO2 these layers contain 25% of perfectly ordered vacancies in the surface and subsurface allowing well-defined measurements of the properties of ceria in the limit of extreme reduction. Experimentally, c-Ce2O3(111) layers are easily identified by a characteristic 4 × 4 surface reconstruction with respect to CeO2(111). In addition, c-Ce2O3 layers represent an experimental realization of a normally unstable polymorph of Ce2O3. During interfacial reaction, c-Ce2O3 nucleates on the interface between CeO2 buffer and Ce overlayer and is further stabilized most likely by the tetragonal distortion of the ceria layers on Cu. The characteristic kinetics of the metal-oxide interfacial reactions may represent a vehicle for making other metastable oxide structures experimentally available.

  8. Effect of precipitants on Ni-CeO2 catalysts prepared by a co-precipitation method for the reverse water-gas shift reaction

    Institute of Scientific and Technical Information of China (English)

    王路辉; 刘辉; 刘源; 陈英; 杨淑清

    2013-01-01

    A series of Ni-CeO2 catalysts were prepared by co-precipitation method with Na2CO3, NaOH, and mixed precipitant (Na2CO3:NaOH;1:1 ratio) as precipitant, respectively. The effect of the precipitants on the catalytic performance, physical and chemical properties of Ni-CeO2 catalysts was investigated with the aid of X-ray diffraction (XRD), Brumauer-Emmett-Teller method (BET), Fou-rier-transform infrared spectroscopy (FT-IR), thermogravimetry (TG), and H2-TPR characterizations. The Ni-CeO2 catalysts were exam-ined with respect to their catalytic performance for the reverse water-gas shift reaction, and their catalytic activities were ranked as:Ni-CeO2-CP (Na2CO3:NaOH=1:1)>Ni-CeO2-CP(Na2CO3)>Ni-CeO2-CP(NaOH). Correlating to the characteristic results, it was found that the catalyst prepared by co-precipitation with mixed precipitant (Na2CO3:NaOH; 1:1 ratio) as precipitant had the most amount of oxygen vacancies accompanied with highly dispersed Ni particles, which made the corresponding Ni-CeO2-CP(Na2CO3:NaOH=1:1) catalyst exhibit the highest catalytic activity. While the precipitant of Na2CO3 or NaOH resulted in less or no oxygen vacancies in Ni-CeO2 catalysts. As a result, Ni-CeO2-CP(Na2CO3) and Ni-CeO2-CP(NaOH) catalysts presented poor catalytic performance.

  9. Magnetic Phase Transitions of CeSb. I

    DEFF Research Database (Denmark)

    Fischer, Pernille Hertz; Lebech, Bente; Meier, G.;

    1978-01-01

    The magnetic ordering of the anomalous antiferromagnet CeSb, which has a NaCl crystal structure, was determined in zero applied magnetic field by means of neutron diffraction investigations of single crystals and powder. Below the Neel temperature TN of (16.1+or-0.1)K, there exist six partially...

  10. Evaluation of production samples of the scintillators LaBr3:Ce andLaCl3:Ce

    Energy Technology Data Exchange (ETDEWEB)

    Choong, Woon-Seng; Derenzo, Stephen E.; Moses, William W.

    2005-09-15

    We report on the evaluation of the performance of two recently developed scintillator materials, LaCl{sub 3}:Ce and LaBr{sub 3}:Ce, at the task of gamma ray spectroscopy. Their performance is compared to a standard scintillator used for gamma ray spectroscopy--a 25 mm diameter 25 mm tall cylinder of NaI:Tl. We measure the pulse height, energy resolution, and full-energy efficiency of production LaBr{sub 3}:Ce and LaCl{sub 3}:Ce scintillation crystals of different sizes and geometries for a variety of gamma-ray energies. Using production rather than specially selected crystals will establish whether immediate large-scale use is feasible. The crystal is excited by gamma rays from one of six isotopic sources ({sup 125}I, {sup 241}Am, {sup 57}Co, {sup 22}Na, {sup 137}Cs, and {sup 60}Co) placed 15 cm away from the scintillator. Our measurements show that both LaCl{sub 3} and LaBr{sub 3} outperform NaI:Tl in almost all cases. They outperform NaI:Tl at all energies for the photopeak fraction and counting rate measurements, and for energy resolution at higher energies (above 200 keV for LaCl{sub 3} and 75 keV for LaBr{sub 3}). The performance of production crystals is excellent and these scintillators should be considered for immediate use in systems where stopping power and energy resolution are crucial.

  11. DNA sequencing by CE.

    Science.gov (United States)

    Karger, Barry L; Guttman, András

    2009-06-01

    Sequencing of human and other genomes has been at the center of interest in the biomedical field over the past several decades and is now leading toward an era of personalized medicine. During this time, DNA-sequencing methods have evolved from the labor-intensive slab gel electrophoresis, through automated multiCE systems using fluorophore labeling with multispectral imaging, to the "next-generation" technologies of cyclic-array, hybridization based, nanopore and single molecule sequencing. Deciphering the genetic blueprint and follow-up confirmatory sequencing of Homo sapiens and other genomes were only possible with the advent of modern sequencing technologies that were a result of step-by-step advances with a contribution of academics, medical personnel and instrument companies. While next-generation sequencing is moving ahead at breakneck speed, the multicapillary electrophoretic systems played an essential role in the sequencing of the Human Genome, the foundation of the field of genomics. In this prospective, we wish to overview the role of CE in DNA sequencing based in part of several of our articles in this journal.

  12. EM BUSCA DE UM VIVER SAUDÁVEL: RELATO DE EXPERIÊNCIA COM UM GRUPO DE IDOSOS CADASTRADOS NA ESTRATÉGIA SAÚDE DA FAMÍLIA DE PACATUBA - CE

    Directory of Open Access Journals (Sweden)

    PATRÍCIA MARIA TAVARES CAVALCANTE

    2007-01-01

    Full Text Available El estudio objetivó relatar la experiencia de trabajar con un grupo de ancianos con catastro en la estrategia Salud de la Família de Pacatuba-CE; en las actividades de recreación y conocimiento. Se recortaron doce meses de actividades para este relato. El grupo llamado” Stamaqui” se inició en mayo de 2003, con 28 personas mayores. Los asuntos discutidos tratan de la salud, el estatuto del anciano, la jubilacion, etc. Además de la realización de estas actividades, se les sirvió el desayuno, se hicieron paseos y cambios de experiencias entre los participantes y los profesionales. Se deseó, con todo esto, despertar en los profesionales de la salud y en los gestores el interés sobre el envejecimiento y la vejez, así como la posibilidad de ampliar conceptos y sensibilizar inversiones dirigidas hacia este porcentaje de la población para mantener una vida sana, a pesar de algunas enfermedades crónicas.

  13. Heavy Fermion Character in Ce2Sb and Ce2Bi

    Science.gov (United States)

    Oyamada, Akira; Isobe, Atsushi; Kitazawa, Hideaki; Ochiai, Akira; Suzuki, Takashi; Kasuya, Tadao

    1993-05-01

    Magnetic susceptibilities, electrical resistivities and specific heats of Ce2Sb, Ce2Bi and CeLaBi were measured to clarify these physical properties. The most characteristic points of these compounds are the following. Ce site are two dimensional and the distance between Ce atoms are very small. The similarity between these compounds and CeRh3B2, in which Ce sites are one dimensional and the distance between Ce atoms are very small, are discussed.

  14. Shape controlled synthesis and tribological properties of CeVO4 nanoparticles as lubricating additive

    Institute of Scientific and Technical Information of China (English)

    LIU Fengzhen; SHAO Xin; YIN Yibin; ZHAO Limin; SHAO Zhuwei; LIU Xuehua; MENG Xianhua

    2011-01-01

    Shape controlled structure of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4· 12H2O and Ce(NO3)3·6H2O.The resulting products were characterized by X-ray powder diffraction (XRD),electron microscopy (SEM) and other techniques.On the basis of the experimental results,CeVO4 nanoparticles exhibited the crystal tetragonal structure and the pH value of solution had an important effect on the crystal structure and morphology of CeVO4 nanoparticles.Furthermore,the tribological properties of CeVO4 nanoparticles as additives in liquid paraffin were evaluated on a four-ball tester.The results indicated that the wear resistance was improved by the additive CeVO4 nanoparticles which exhibited very good antiwear and friction reduction performance in wear.

  15. Efeitos da VariaÃÃo Sazonal de um banco de Halodule wrightii Ascherson sobre comunidades bentÃnicas associadas, na Praia das Goiabeiras, Fortaleza-CE

    OpenAIRE

    kcrishna Vilanova de Souza Barros

    2008-01-01

    No Brasil, o grau de variaÃÃo de caracteres morfolÃgicos especÃficos de Halodule wrightii tem sido raramente reportado na literatura, dificultando a comparaÃÃo entre bancos de diferentes Ãreas. Estudos sobre assemblÃias faunÃsticas associadas tambÃm sÃo considerados raros, sobretudo, com relaÃÃo Ãs interaÃÃes planta-animal. Fatores ambientais podem influenciar fortemente a morfologia das plantas, mas existem poucos estudos ambientais que demonstram esse fato para a espÃcie H. wrightii. No est...

  16. Controllable preparation of CeO2 nanostructure materials and their catalytic activity

    Institute of Scientific and Technical Information of China (English)

    Shan Wenjuan; Guo Hongjuan; Liu Chang; Wang Xiaonan

    2012-01-01

    Well-crystalline CeO2 nanostructures with the morphology ofnanorods and nanocubes were synthesized by a template-free hydrothermal method.X-ray diffraction (XRD),transmission electron microscopy (TEM),Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption measurements were employed to characterize the synthesized materials.The reducibility and catalytic activity of nanostructured CeO2 were examined by hydrogen temperature-programmed reduction (H2-TPR) and CO oxidation.The results showed that CeO2 nanorods could be converted into CeO2 nanocubes with the increasing of the reaction time and the hydrothermal temperature,CeO2 nanorods became longer gradually with the increasing of the concentrations of NaOH.H2-TPR characterization demonstrated that the intense low-temperature reduction peak in the CeO2 nanorods indicated the amount of hydrogen consumed is larger than CeO2 nanocubes.Meantime the CeO2 nanorods enhanced catalytic activity for CO oxidation,the total conversion temperature was 340 ℃.The reasons were that CeO2 nanorods have much smaller crystalline sizes and higher surface areas than CeO2 nanocubes.

  17. Performance comparison between ceramic Ce:GAGG and single crystal Ce:GAGG with digital-SiPM

    Science.gov (United States)

    Park, C.; Kim, C.; Kim, J.; Lee, Y.; Na, Y.; Lee, K.; Yeom, J. Y.

    2017-01-01

    The Gd3Al2Ga3O12 (Ce:GAGG) is a new inorganic scintillator known for its attractive properties such as high light yield, stopping power and relatively fast decay time. In this study, we fabricated a ceramic Ce:GAGG scintillator as a cost-effective alternative to single crystal Ce:GAGG and, for the first time, investigated their performances when coupled to the digital silicon photomultiplier (dSiPM)—a new type of photosensor designed for applications in medical imaging, high energy and astrophysics. Compared to 3 × 3 × 2 mm3 sized single crystal Ce:GAGG, the translucent ceramic Ce:GAGG, which has a much lower transmittance than the single crystal, was determined to give an output signal amplitude that is approximately 61% of single crystal Ce:GAGG. The energy resolution of the 511 keV annihilation peak of a 22Na source was measured to be 9.9 ± 0.2% and 13.0 ± 0.3% for the single and ceramic scintillators respectively. On the other hand, the coincidence resolving time (CRT) of ceramic Ce:GAGG was 307 ± 23 ps, better than the 465 ± 37 ps acquired with single crystals—probably attributed to its slightly faster decay time and higher proportion of the fast decay component. The ceramic Ce:GAGG may be a promising cost-effective candidate for applications that do not require thick scintillators such as x-ray detectors and charged particle detectors, and those that require time-of-flight capabilities.

  18. Challenges in the training of new teachers of Geography. Knowledge and experience exchanges with fishermen from Batoque, Aquiraz-Ceará. Oficina de GPS para pescadores na Reserva Extrativista do Batoque – Aquiraz /CE

    Directory of Open Access Journals (Sweden)

    Alexsandra Bezerra Rocha

    2012-10-01

    Full Text Available An account on a teaching experiment carried out on the Extractive Reserve of Batoque-Ceará, involving fourteen fishermen whose great majority was unable to read or write. This reflection focuses on how a Geography licensed teacher can act in face of a community need to learn how to use a GPS device. The methodology consisted in the setting up of a 20-hour workshop using cardboard signs (drawings and numbers, followed by the individual handling of a GPS device, this way increasing the value of the fishermen’s knowledge. The exercises drilled gave the group the opportunity to learn about the importance of using technology in its fish-catching activity (marking and entering a position, wind direction, distances in metres, quilometres, course, degrees, compass and route. It was observed that the incorporation of technology means a change in tradition, in the “secret of doing the thing.” There was an exchange of ideas and information between university scholarship and the fishermen’s everyday knowledge.Relato sobre experiência de ensinar realizada na Reserva Extrativista do Batoque – Ceará, com 14 pescadores, que a grande maioria não sabia ler e nem escrever. Em foco refletir sobre como pode se dar a atuação do professor licenciado em Geografia diante de uma demanda comunitária de ensinar a usar um instrumento de posicionamento global - GPS. A metodologia consistiu na realização de uma oficina de 20 horas com a utilização de cartazes em papel madeira (desenhos e números, e, em seguida o manejo individual do aparelho de GPS, valorizando o saber dos pescadores. Os exercícios trabalhados proporcionaram ao grupo apreender o significado do uso da tecnologia na atividade pesqueira (marcar a localização/posição, inserir uma posição, direção dos ventos, distância em metros, quilômetros, rumo, grau, bússola e rotas. Constatou-se que a incorporação da tecnologia implica a possibilidade da mudança de uma tradição (

  19. Scintillating properties of LiYSiO4:Ce

    Institute of Scientific and Technical Information of China (English)

    FU Zai-Wei; CHEN Xiao-Hui; NING Zhe; HENG Yue-Kun; QI Ming; HUANG Pin-Wen; ZHANG Huai-Jin; WANG Ji-Yang; JIA Ru; QIAN Sen; LI Shao-Li

    2011-01-01

    LiYSiO4:Ce is a promising scintillator and some of its properties have been reported in previous papers.In this paper,samples doped with different concentrations of Ce are prepared and studied.First,the relative light yields of the samples are measured as 28.1%-37.1% compared with a standard anthracene crystal being irradiated by α particles and as ~27.2% compared with NaI being irradiated by X-rays.Second,the effects of sample thicknesses on light yields are presented.Finally the timing behaviors of samples with different doped concentrations being irradiated with alpha particles and X-rays are discussed.The result shows that LiYSiO4:Ce is a kind of fast scintillator (~ 30 ns) with a moderate light yield that can be used for neutron detection.

  20. Qualidade da atenção ao pré-natal na Estratégia Saúde da Família em Sobral, Ceará Calidad de la atención en el pre-natal en la Estrategia Salud de Familia en Sobral, CE, Brasil Quality of pre-natal care in Family Health Strategy in Sobral, CE, Brazil

    Directory of Open Access Journals (Sweden)

    Francisco Rosemiro Guimarães Ximenes Neto

    2008-10-01

    Full Text Available Diante das políticas públicas que envolvem a qualidade da atenção ao pré-natal, este estudo teve como objetivo avaliar a qualidade da atenção ao pré-natal nos territórios da Estratégia Saúde da Família, do município de Sobral, à luz do referencial teórico de Avedis Donabedian. Trata-se de um estudo de caráter descritivo-exploratório, desenvolvido em Centros de Saúde da Família de Sobral, Ceará. Dos quatorze Centros de Saúde investigados, quatro se mostraram com indicadores adequados para o pré-natal. Porém, ainda que existam inadequações na estrutura física, não existem impedimentos para que se ofereça um atendimento de qualidade haja vista que o processo e os resultados também interferem na qualidade da assistência.Frente a las políticas públicas que impliquen la calidad de la atención a la salud prenatal, el estudio tiene como objetivo: evaluar la calidad de la atención prenatal a los territorios en la Estrategia de Salud de la Familia de la ciudad de Sobral, a la luz del referencial teórico de AVEDIS Donabedian. Se trata de un estudio exploratorio de carácter descriptivo, desarrollado por los Centros de Salud Familiar de Sobral - Ceará. De los catorce Centros de Salud investigaron, cuatro fueron con los indicadores apropiados para la atención prenatal. Pero a pesar de que hay deficiencias en la estructura física, no hay impedimentos a fin de proporcionar una calidad de la atención hay una opinión de que el proceso y los resultados también interferir con la calidad de la atención.Face to public policies involving the quality of care for prenatal, the study aims to: assess the quality of prenatal care to the territories in the Family Health Strategy of the city of Sobral in the light of theoretical reference of Avedis Donabedian. This is a descriptive- exploratory study, developed by Family Health Units of Sobral, CE, Brazil. Of the fourteen Centers Health investigated, four were with appropriate

  1. Biomassa microbiana e matéria orgânica leve em solos sob sistemas agrícolas orgânico e convencional na Chapada da Ibiapaba - CE Microbial biomass and light organic matter in soils under organic and conventional systems in the Chapada da Ibiapaba - CE, Brazil

    Directory of Open Access Journals (Sweden)

    Francisco Alisson da Silva Xavier

    2006-04-01

    Full Text Available Em muitos casos, a substituição da vegetação nativa por sistemas agrícolas resulta em decréscimo nos conteúdos de C e N nos diferentes compartimentos da matéria orgânica do solo. Para testar se as práticas de manejo que priorizam o aporte de resíduos orgânicos promovem aumento dos compartimentos da matéria orgânica mais sensíveis ao manejo, este estudo se propôs estudar áreas de uma propriedade que utiliza um sistema de produção de acerola em larga escala, sob manejo orgânico, e uma área sob cultivo convencional de cenoura e beterraba em rotação com milho, pertencentes à Fazenda Amway Nutrilite do Brasil e à Associação de Horticultores do Pivot Central, respectivamente, ambas localizadas na região da Chapada da Ibiapaba, Ceará. Selecionou-se, também, uma área de pastagem localizada no interior da primeira propriedade amostrada, bem como áreas sob mata nativa, próximas às áreas de cultivo. Amostras de um Neossolo Quartzarênico foram coletadas nas profundidades de 0-5 e 5-15 cm e foram determinados os teores de C orgânico total, de C e N microbiano (Cmic e Nmic e da matéria orgânica leve (Cmol e Nmol, além do C mineralizável obtido por respirometria. O acúmulo médio nos estoques de Nmic nas áreas sob manejo orgânico em relação à mata nativa foi de 11,7 kg ha-1, o que representou um incremento de 585 % de Nmic nas áreas de cultivo. Já na pastagem, ocorreu acúmulo de 211 kg ha-1 no estoque de Cmic em relação à mata nativa em subsuperfície, representando um incremento de 514,6 %. Por outro lado, os estoques de Cmic no cultivo convencional sofreram reduções de 59 e 53 %, nas camadas de 0-5 e de 5-15 cm, respectivamente, em relação à mata nativa. Os estoques de Cmol obtidos nas linhas de cultivo nos sistemas orgânicos apresentaram incremento de 106 %, na camada de 0-5 cm, em relação à mata; no sistema convencional, porém, constatou-se uma redução em 31 % no estoque de Cmol na camada

  2. File list: NoD.ALL.50.NA.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  3. File list: NoD.ALL.05.NA.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  4. File list: NoD.Unc.05.NA.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Unc.05.NA.AllCell ce10 No description NA Unclassified SRX216762,SRX216757,SRX21...278070,SRX278067,SRX278069 http://dbarchive.biosciencedbc.jp/kyushu-u/ce10/assembled/NoD.Unc.05.NA.AllCell.bed ...

  5. Signature splitting in 129Ce

    Institute of Scientific and Technical Information of China (English)

    LIU Ying; WU Xiao-Guang; ZHU Li-Hua; LI Guang-Sheng; HE Chuang-Ye; LI Xue-Qin; PAN Bo; HAO Xin; LI Li-Hua; WANG Zhi-Min; LI Zhong-Yu; XU Qiang

    2009-01-01

    The high spin states of 129Ce have been populated via heavy-ion fusion evaporation reaction 96Mo (37C1, 1p3n) 129Ce. The γ-γ coincidence and intensity balance used to measure the B(M1; I→I-1)/B(E2; I→I-2) (the probability ratio of the dipole and quadrupole transition) in v7/2[523] rotational band of 129Ce. And the energy splitting (Δe') has been got through the experimental Routhians. The lifetimes and quadrupole moments Qt have been extracted from the lineshape analyses using DSAM. The deformation of the v7/2[523] rotational band of 129Ce was extracted from the Qt and moment of inertia JRR.

  6. Freqüência e atividade enzimática de Candida spp. na cavidade oral de pacientes diabéticos do serviço de endocrinologia de um hospital de Fortaleza-CE Frequency and enzymatic activity of Candida spp. oral cavity of diabetic patients of the service of endocrinology of a hospital of Fortaleza-CE

    Directory of Open Access Journals (Sweden)

    Everardo Albuquerque Menezes

    2007-08-01

    Full Text Available O diabetes mellitus (DM, uma doença endócrino-metabólica de alta e crescente prevalência, é citada como responsável pela ocorrência das candidíases orais. A candidíase constitui um espectro de infecções causadas por fungos do gênero Candida, sendo o seu agente mais comum a Candida albicans, embora outras espécies tenham sido identificadas (Candida tropicalis, Candida guillermondii, Candida glabrata, Candida krusei. O objetivo deste trabalho foi avaliar a freqüência e a atividade enzimática de Candida spp. na cavidade oral de pacientes diabéticos atendidos no Serviço de Endocrinologia do Hospital Universitário Walter Cantídio da Universidade Federal do Ceará (HUWC/UFC. Foram coletadas amostras de 48 pacientes diabéticos, de ambos os sexos, com situações variáveis de controle glicêmico. Os materiais clínicos foram colhidos com ajuda de swabs e semeados em placas de Petri contendo ágar-Sabouraud dextrose com cloranfenicol e incubado a 37°C. Os crescimentos foram identificados pelas provas clássicas usadas em micologia. Depois, essas cepas de Candida foram submetidas a provas de detecção de enzimas fosfolipase e proteinase. Destas, 15 amostras (31,25% apresentaram cultura positiva para o gênero Candida. A espécie mais freqüente foi a C. albicans, com 80%, seguida de C. tropicalis (13,3% e C. guillermondii (6,7%. Quanto à pesquisa da atividade enzimática de Candida spp., foi observado que 86,6% delas apresentaram atividade de proteinase e 80%, de fosfolipase. Conclui-se com tais resultados que a C. albicans é a mais freqüente e que as espécies de Candida isoladas possuem fortes atividades enzimáticas.Diabetes mellitus, a endocrine-metabolic disease, of high and increasing prevalence, is cited as responsible by the occurrence of oral candidiasis. Candidiasis constitutes a specter of infections caused by fungi of genera Candida; the most common agent is Candida albicans, but other species have also been

  7. SELF-ASSEMBLY CE OXIDE/ORGANOPOLYSILOXANE COMPOSITE COATINGS.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.; SABATINI,R.; GAWLIK,K.

    2005-01-01

    A self-assembly composite synthesis technology was used to put together a Ce(OH){sub 3}-dispersed poly-acetamide-acetoxyl methyl-propylsiloxane (PAAMPA) organometallic polymer. Three spontaneous reactions were involved; condensation, amidation, and acetoxylation, between the Ce acetate and aminopropylsilane triol (APST) at 150 C. An increase in temperature to 200 C led to the in-situ phase transformation of Ce(OH){sub 3} into Ce{sub 2}O{sub 3} in the PAAMPA matrix. A further increase to 250 C caused oxidative degradation of the PAAMPA, thereby generating copious fissures in the composite. We assessed the potential of Ce(OH){sub 3}/ and Ce{sub 2}O{sub 3}/ PAAMPA composite materials as corrosion-preventing coatings for carbon steel and aluminum. The Ce{sub 2}O{sub 3} composite coating displayed better performance in protecting both metals against NaCl-caused corrosion than did the Ce(OH){sub 3} composite. Using this coating formed at 200 C, we demonstrated that the following four factors played an essential role in further mitigating the corrosion of the metals: First was a minimum susceptibility of coating's surface to moisture; second was an enhanced densification of the coating layer; third was the retardation of the cathodic oxygen reduction reaction at the metal's corrosion sites due to the deposition of Ce{sub 2}O{sub 3} as a passive film over the metal's surface; and, fourth was its good adherence to metals. The last two factors contributed to minimizing the cathodic delamination of coating film from the metal's surface. We also noted that the affinity of the composite with the surface of aluminum was much stronger than that with steel. Correspondingly, the rate of corrosion of aluminum was reduced as much as two orders of magnitude by a nanoscale thick coating. In contrast, its ability to reduce the corrosion rate of steel was lower than one order of magnitude.

  8. RESONANT PHOTOEMISSION OF BULK CeO2 AND NANO—CeO2 FILMS

    Institute of Scientific and Technical Information of China (English)

    M.I.Abbas; K.Ibrahim; Z.Y.Wu; J.Zhang; F.Q.Liu; H.J.Qian

    2001-01-01

    Photoemission behaviors of nano-CeO2 films with parlicle sizes ranging from 8nm to 50nm and bulk CeO2 in Ce 4d-4f absorption region have been investigated.Resonant enhancements of Ce 4f valance band and Ce 5p bands for nano film and bulk material have been observed.The variation of electron density of Ce 4d-4f resonace.

  9. Structural characterization and corrosive property of Ni-P/CeO2composite coating

    Institute of Scientific and Technical Information of China (English)

    JIN Huiming; JIANG Shihang; ZHANG Linnan

    2009-01-01

    Electroless Ni-P/nano-CeO2 composite coating was prepared in acidic condition, and its microstructure and corrosive property were compared with its CeO2-free counterpart. Scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), X-ray diffraction spectrometer (XRD), and differential scanning calorimeter (DSC) were used to examine surface morphology and microstructure of the coating. Corrosive investigation was carried out in 3%NaCl+5%H2SO4 solution. The results showed that Ni-P coating had partial amorphous structure mixed with nanocrystals, whereas the Ni-P/CeO2 coating had perfect amorphous structure. In high temperature condition, Ni3P precipitation and Ni crystallization occurred in both coatings but at different temperatures, whereas the Ni-P/CeO2 coating had sintered phase of NiCe2O4 spinels. The anticorrosion property and passivity were improved in the CeO2-containing coating due to its less liability to undergo local-cell corrosion than its CeO2-free counterpart. During the co-deposition process, some Cen+ (n=3, 4) ions may be adsorbed to the metal/solution interface, hinder nickel's crystal-typed deposition and promote phosphorous deposition. The nano-CeO2 doping finally resulted in the coating' perfect amorphous structure and good anti-corrosive property.

  10. Microstructure and corrosion behavior of electroless deposited Ni-P/CeO2 coating

    Institute of Scientific and Technical Information of China (English)

    Hui Ming Jin; Shi Hang Jiang; Lin Nan Zhang

    2008-01-01

    Electroless Ni-P/nano-CeO2 composite coating was prepared in acidic condition,and its microstructure and corrosive property were compared with its CeO2-free counterpart.Scanning electronic microscopy (SEM) and X-ray diffraction (XRD) spectrometer were used to examine surface morphology and structure of the as-plated coating.Differential scanning calorimeter (DSC) and transmission electronic microscopy (TEM) were used to study the coating's phase change at high temperature.The coating's corrosive behavior in 3%NaCI + 5%H2SO4 solution was also investigated.The results showed that Ni-P coating had partial amorphous structure mixed with nano-crystals,while the Ni-P/CeO2 coating had perfect amorphous structure.In high-temperature condition,Ni3P precipitation and Ni crystallization took place in both coatings but at different temperatures,while the Ni-P/CeO2 coating had sintered phase of NiCe2O4 spinels.The anti-corrosion property was better in the CeO2-containing coating,and this was due to its less liability to undergo local-cell corrosion than its CeO2-free counterpart.Ni-P/CeO2 coating's pure amorphous structure was the result of Ni's hindered crystal-typed deposition and P's promoted deposition.

  11. Preparation and characterization of Cu-Ce-La mixed oxide as water-gas shift catalyst for fuel cells application

    Institute of Scientific and Technical Information of China (English)

    ZHI Keduan; LIU Quansheng; ZHAO Ruigang; HE Runxia; ZHANG Lifeng

    2008-01-01

    Cu-Ce-La mixed oxides were prepared by three precipitation methods (coprecipitation, homogeneous precipitation, and deposition precipitation) with variable precipitators and characterized using X-ray diffraction, BET, temperature-programmed reduction, and catalytic reaction for the water-gas shift. The Cu-Ce-La mixed oxide prepared by coprecipitation method with NaOH as precipitator presented the highest activity and thermal stability. Copper ion substituted quadrevalent ceria entered CeO2 (111) framework was in favor of activity and thermal stability of catalyst. The crystallinity of fresh catalysts increased with the reduction process. La3+ or Ce4+ substituted copper ion entered the CeO2 framework during reduction process. The coexistence of surface copper oxide (crystalline) and pure bulk crystalline copper oxide both contributed to the high activity and thermal stability of Cu-Ce-La mixes oxide catalyst.

  12. Ženy na trhu práce

    OpenAIRE

    Nová, Lucie

    2016-01-01

    The objective of this thesis is to analyze and verify the existence of causality between employment rate, unemployment rate as independent variable and fertility rate as dependent variable. Two stated hypotheses are being verified within this thesis. First of them says that by decreasing employment rate also the fertility rate decreases. Second says that decreasing unemployment rate has an impact on growth of fertility rate. The final part of essay deals with today´s often discussed concept o...

  13. RESONANT PHOTOEMISSION OF BULK CeO2 AND NANO-CeO2 FILMS

    Institute of Scientific and Technical Information of China (English)

    M.I. Abbas; K. Ibrahim; Z.Y. Wu; J. Zhang; F.Q. Liu; H.J. Qian

    2001-01-01

    Photoemission behaviors of nano-CeO2 films with particle sizes ranging from 8nm 1o50nm and bulk CeO2 in Ce 4d-4f absorption region have been investigated. Resonantenhancements of Ce 4f valance band and Ce 5p bands for nano film and bulk materialhave been observed. The variation of electron density of states in valance bands ofnano and bulk structures of CeO2 is discussed in terms of Ce 4d-4f resonance.

  14. Effects of Ce3+ on Physiological Characteristics of Spirulina under Salt Stress%稀土Ce3+对盐胁迫下螺旋藻生理特性的影响

    Institute of Scientific and Technical Information of China (English)

    巩东辉; 王志忠; 李国龙; 张少英; 谢庆超

    2013-01-01

    The effects of Ce + on the growth of Spirulina from Chad lake of Africa under 0. 3 mol·L-1 NaCl stress were studied by the physiological method. The results showed that Ce3+ could promote the growth and the accumulation of chlorophyll a in the range of 8. 104 ~ 16. 208 μmol·L-1; and promote the synthesis of soluble protein of Spirulina in the range of 16.208 ~ 48. 62 μmol·L-1; the content of MDA was the highest when the concentration of Ce 3+ was 8.104 μmol·L , and dropped with the increasing of content of Ce+. Ce3+could relieve the salt stress to Spirulina in a certain range, could promote the accumulation of chlorophyll a and soluble protein of Spirulina, and reduced the content of MDA. And the high Ce3 + concentration could aggravate the damage to the algae cells by cooperating with NaCl and inhibited the growth of Spirulina.%以非洲乍得湖钝顶螺旋藻为实验材料,在0.3 mol·L-1 NaCl胁迫下,通过生理学方法研究了不同浓度Ce3+对螺旋藻生长的影响.结果表明:Ce3+浓度在8.104 ~16.208 μmol·L-1之间时,促进了螺旋藻的生长以及叶绿素a的合成;Ce3+浓度在16.208 ~48.62 μmol·L-1之间时,促进可溶性蛋白的合成;Ce3+浓度为8.104μmol·L-1时藻体MDA含量最高,之后MDA含量随着Ce3+处理浓度的增加逐步降低.这说明Ce3+在一定的浓度范围内可减轻NaCl对螺旋藻的胁迫作用,促进螺旋藻可溶性蛋白和叶绿素a的积累,降低藻细胞MDA的浓度,高浓度Ce3+则会与NaCl协同、抑制螺旋藻的生长.

  15. Reduction behavior of cerium(Ⅲ) ions in NaCl-2CsCl melt

    Institute of Scientific and Technical Information of China (English)

    QI Xue; ZHU Hongmin

    2005-01-01

    The cathodic process of cerium(Ⅲ) ions in NaCl-2CsCl melt was studied by cyclic voltammetry and square wave voltammetry with tungsten and gold electrodes at 873 K. The two electroanalytical methods yield similar results. The cathodic process of cerium(Ⅲ) ions consists of two reversible steps: Ce3+ + e-= Ce2+ and Ce2+ + 2e-= Ce. The half wave potentials of Ce3+/Ce2+ and Ce2+/Ce were determined as -2.525 V vs. Cl2/Cl- and -2.975 V vs. Cl2/Cl-, respectively. The diffusion coefficient of Ce3+ was also determined as 5.5 × 10-5 cm2·s-1.

  16. Sensitization of Tb3+ Luminescence in NaGdSiO4

    NARCIS (Netherlands)

    Kiliaan, H.S.; Herwijnen, S.P. van; Blasse, G.

    1987-01-01

    The luminescence properties of the system Na(Gd,S,Tb)SiO4 (S = Ce3+ or Bi3+) are reported, for the orthorhombic olivine modification as well as for the tetragonal NaF-stabilized modification. The Tb3+ luminescence can be sensitized by Ce3+, Gd3+ or Bi3+. The efficiencies of the several processes are

  17. Ce que permet le document

    OpenAIRE

    2012-01-01

    Avec l’archive, à laquelle il est souvent associé, le document occupe une place centrale dans les expositions comme dans les publications actuelles sur l’art contemporain. Les présents ouvrages n’ont pas pour objectif d’apporter un éclairage à ce vaste tournant mnémonique qui semble s’emparer des pratiques et des discours sur l’art depuis le début de ce troisième millénaire, même si les contributions de certains de leurs auteurs pointent des éléments conjoncturels (l’après 11 septembre) ou te...

  18. Luminescence and scintillation properties of BaF2sbnd Ce transparent ceramic

    Science.gov (United States)

    Luo, Junming; Sahi, Sunil; Groza, Michael; Wang, Zhiqiang; Ma, Lun; Chen, Wei; Burger, Arnold; Kenarangui, Rasool; Sham, Tsun-Kong; Selim, Farida A.

    2016-08-01

    Cerium doped Barium Fluoride (BaF2sbnd Ce) transparent ceramic was fabricated and its luminescence and scintillation properties were studied. The photoluminescence shows the emission peaks at 310 nm and 323 nm and is related to the 5d-4f transitions in Ce3+ ion. Photo peak at 511 keV and 1274 keV were obtained with BaF2sbnd Ce transparent ceramic for Na-22 radioisotopes. Energy resolution of 13.5% at 662 keV is calculated for the BaF2sbnd Ce transparent ceramic. Light yield of 5100 photons/MeV was recorded for BaF2sbnd Ce(0.2%) ceramic and is comparable to its single crystal counterpart. Scintillation decay time measurements shows fast component of 58 ns and a relatively slow component of 434 ns under 662 keV gamma excitation. The slower component in BaF2sbnd Ce(0.2%) ceramic is about 200 ns faster than the STE emission in BaF2 host and is associated with the dipole-dipole energy transfer from the host matrix to Ce3+ luminescence center.

  19. Effect of fluxes on structure and luminescence properties of Y3Al5O12:Ce3+ phosphors

    Institute of Scientific and Technical Information of China (English)

    XU Shiqing; SUN Liuzheng; ZHANG Ying; JU Haidong; ZHAO Shilong; DENG Degang; WANG Huanping; WANG Baoling

    2009-01-01

    Ce3+-activated yttrium aluminum garnet (YAG) was prepared by the solid-state reaction, in which H3BO3, LiF, NaF, KF and BaF2 were used as the fluxes. The effect of fluxes on optical properties of phosphors was studied in detail, especially the fluxes of alkali fluorides, which could enhance the emission intensity and change the wavelength of emission peaks. Among these YAG:Ce phosphors, the phosphor sintered with H3BO3 and NaF exhibited the strongest emission. The emission peaks of phosphors prepared with fluxes from LiF to KF were shifted to long wavelength. The effect of NaF concentration on the emission intensity of YAG:Ce was also investigated. The value of emis-sion intensity reached the maximum when the concentration of NaF was 0.5%.

  20. Preparation of High-Surface Area Nano-CeO2 by Template-Assisted Precipitation Method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The high-surface area nano-CeO2 was prepared by Ce(NO3)3 by precipitation method, with surfactant cetyltrimethyl ammonium bromide (CTAB) as templating agent. The effects of the precipitating agents, reaction temperature, ageing time, and calcination temperature on the surface area, as well as the pore structure and the mean crystallite size of nano-CeO2 were studied. It was found that the reaction of Ce(NO3)3 with NaOH in the presence of CTAB at 90 ℃ for 12 h yieldsed a cerium oxide/surfactant mixture, which after calcination at 400 ℃ resulted in high-surface area nano-CeO2. The mean crystallite size of CeO2 was approximately 6 nm, surface area was in excess of 200 m2·g-1, pore size was approximately 9 nm, and the pore distribution was concentrative. Moreover, the surface area can still reach 147 m2·g-1 after calcination at 700 ℃, which showed the good thermal stability of the CeO2. The number of oxygen vacancies in the structure of CeO2 corresponded with the surface area of CeO2, and the high surface area was propitious to the formation of oxygen vacancies.

  1. A Study of the Kinetics of the Electrochemical Deposition of Ce3+/Ce4+ Oxides

    Science.gov (United States)

    Valov, I.; Guergova, Desislava; Stoychev, D.

    The kinetics of cathodic electrodeposition of Ce3+ and/or Ce4+ oxides from alcoholic electrolytes on gold substrates has been studied. It was found that, depending on the oxygen content in the CeCl3-based electrolyte, Ce2O3 (in oxygen atmosphere) or CeO2 (in an inert atmosphere), respectively, were obtained. XPS studies clearly separated the two valence states of Ce ions in the oxide layers. The microstructure of the coatings was analyzed by atomic force microscopy (AFM).

  2. Characterizations of electrodeposited Ni–CeO{sub 2} nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Kasturibai, S., E-mail: s.kasturibai@yahoo.co.in [Department of Chemistry, Alagappa Government Arts College, Karaikudi 630 003, Tamilnadu (India); Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, School of Chemical Sciences, Alagappa University, Karaikudi 630 003, Tamilnadu (India); Kalaignan, G. Paruthimal, E-mail: pkalaignan@yahoo.com [Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, School of Chemical Sciences, Alagappa University, Karaikudi 630 003, Tamilnadu (India)

    2014-10-15

    The expansion of current machinery requires metallic materials with better surface properties. In the present investigation, CeO{sub 2} reinforced nickel nanocomposite coatings were deposited on mild steel substrate by direct current electrodeposition process employing nickel acetate bath. The effect of incorporation of CeO{sub 2} particles in the Ni nanocomposite coatings on the micro hardness and corrosion behaviour has been evaluated. Smooth and compact nanocomposite deposits containing well-distributed cerium oxide particles were obtained. The crystallite structure was fcc for electrodeposited nickel and Ni–CeO{sub 2} nanocomposite coatings. It has been observed that, the presence of CeO{sub 2} nanoparticles favours the [111] and [200] texture of nickel matrix. The co-deposition of CeO{sub 2} nanoparticles with nickel was found to be favoured at applied current density of 8 A dm{sup −2}. The micro hardness values of the nickel nanocomposite coatings (725 HV) was higher than that of pure nickel (265 HV).The decrease in I{sub corr} values and increase in Constant Phase Element values were investigated in 3.5% NaCl solution which showed the higher corrosion resistant nature of Ni–CeO{sub 2} coatings. - Highlights: • Ni–CeO{sub 2} composite coatings have electrodeposited from eco-friendly acetate bath. • Inclusion of CeO{sub 2} in the composite coating has refined the crystallite size. • Micro hardness values have increased with CeO{sub 2} content in the composite coatings. • The negative shift of E{sub corr} confirming cathodic protective nature of coatings.

  3. Comparative study of CuO-CeO{sub 2} catalysts prepared by wet impregnation and deposition-precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Gurbani, A.; Ayastuy, J.L.; Gonzalez-Marcos, M.P.; Gutierrez-Ortiz, M.A. [Departamento de Ingenieria Quimica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Bilbao 48080 (Spain); Unidad Asociada ' ' Tecnologias Quimicas para la Sostenibilidad Ambiental' ' , CSIC-UPV/EHU (Spain); Herrero, J.E.; Guil, J.M. [Instituto de Quimica Fisica ' ' Rocasolano' ' - CSIC, Madrid 28006 (Spain); Unidad Asociada ' ' Tecnologias Quimicas para la Sostenibilidad Ambiental' ' , CSIC-UPV/EHU (Spain)

    2009-01-15

    Two different preparation methods are used to synthesize wt. 7% CuO-CeO{sub 2} catalysts: a conventional wet impregnation method, and a deposition-precipitation (DP) method using Na{sub 2}CO{sub 3} as precipitating agent. Both samples are characterized by a series of techniques. CuO-CeO{sub 2} (Cu-Ce) prepared by DP shows a lower capacity to release the lattice oxygen to form CO{sub 2}. From CO-TPR results, it is demonstrated that this catalyst is not able to reduce copper clusters at low temperatures. Also, CO-TPD shows no CO{sub 2} formation. The activity results confirm the worse performance of Cu-Ce prepared by DP especially when oxygen is not in excess (PROX reaction with stoichometric oxygen). A copper particle size which is too small could create a stronger metal-support interaction, with lower Cu-Ce interface to react. (author)

  4. Local structure of the Ce3+ ion the yellow emitting phosphor YAG:Ce

    NARCIS (Netherlands)

    Ghigna, P.; Pin, S.; Ronda, C.; Speghini, A.; Piccinelli, F.; Bettinelli, M.

    2011-01-01

    The local structure of the Ce3+ ion in the yellow emitting YAG:Ce phosphor has been studied by Extended X-ray Absorption Fine Structurespectroscopy in the 300−20 K temperature range. It has evidenced that the dopant Ce3+ replaces Y3+ in the garnet structure, giving rise to a significant expan

  5. The role of Ce(III) in BZ oscillating reactions

    Science.gov (United States)

    Nogueira, Paulo A.; Varela, Hamilton; Faria, Roberto B.

    2012-03-01

    Herein we present results on the oscillatory dynamics in the bromate-oxalic acid-acetone-Ce(III)/Ce(IV) system in batch and also in a CSTR. We show that Ce(III) is the necessary reactant to allow the emergence of oscillations. In batch, oscillations occur with Ce(III) and also with Ce(IV), but no induction period is observed with Ce(III). In a CSTR, no oscillations were found using a freshly prepared Ce(IV), but only when the cerium-containing solution was aged, allowing partial conversion of Ce(IV) to Ce(III) by reaction with acetone.

  6. Activity improvement of Pt/C catalysts by adding CeO2 nanoparticles

    Institute of Scientific and Technical Information of China (English)

    YANG Yuying; ZHANG Ziyu; HU Zhongai

    2011-01-01

    Carbon-supported platinum catalysts were prepared by NaBH4 reduction of metal precursors and the CeO2 nanoparticles were prepared by citric acid sol-gel method. The structure and morphology of two kinds of nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The Pt particles were uniformly dispersed on the carbon surface and showed the rod-like morphology. The CeO2 was spherical in shape. The appropriate amount of CeO2 nanoparticles was added into Pt/C systems to improve activity of the catalysts. Several electrochemical techniques such as cyclic voltammogram (CV), chronoamperometry (I-t)and electrochemical impedance spectroscopy (EIS) were used to investigate the properties of CeO2-Pt/C catalysts for methanol electrooxidation in 1 mol/L CH3OH+0.5H2SO4 aqueous solutions. The results revealed that compared with Pt/C catalysts CeO2-pt/C exhibited a higher activity and stability for methanol electro-oxidation. Moreover, the effect of CeO2 content on the activity of Pt/C catalysts was discussed in detail.

  7. On Chinglish in C-E Interpretation

    Institute of Scientific and Technical Information of China (English)

    XIAO Gui-fang; LIU Jian-zhu; GUI Ren-na

    2005-01-01

    Based on the author's survey into the different interpretations of some terms from Chinese into English, the paper points out Chinglish exists universally in C-E interpretation.The author also puts forward some proposals on how to avoid and reduce Chinglish in the process of C-E interpretation after exploring its features and causes of Chinglish.

  8. Spectroscopic analysis of LYSO:Ce crystals

    Science.gov (United States)

    Martins, A. F.; Carreira, J. F. C.; Rodrigues, J.; Sedrine, N. Ben; Castro, I. F. C.; Correia, P. M. M.; Veloso, J. F. C. A.; Rino, L.; Monteiro, T.

    2017-02-01

    Rare earth orthosilicates are among the most widely used scintillator materials in the last decades. Particularly, lutetium-yttrium oxyorthosilicate (LYSO) is known to exhibit great potentialities in the field of radiation detectors for medical imaging. Consequently, an in-depth knowledge of the material properties is of utmost interest for the mentioned applications. In this work the spectroscopic properties of commercial cerium doped lutetium-yttrium oxyorthosilicate crystals (LYSO:Ce) were investigated by Raman spectroscopy, steady state photoluminescence, photoluminescence excitation and time resolved photoluminescence. Site selective excitation was used under steady state (325 nm) and pulsed (266 nm) conditions to separately investigate the temperature dependence of the 5d → 4f Ce1 and Ce2 luminescence, allowing to establish the thermal quenching dependence of the Ce2 optical center. In the case of the Ce1 optical center, a luminescence quantum efficiency of 78% was obtained from 14 K to room temperature with 266 nm photon excitation.

  9. Machining Characteristics of Ce-ZrO2/CePO4 Ceramics

    Institute of Scientific and Technical Information of China (English)

    Yu Aibing; Tan Yefa; Yang Xiaoqiang

    2004-01-01

    Two-phase mixtures of Ce-ZrO2 and monazite-type CePO4 were fabricated. Drilling and grinding experiments were carried out to investigate the machining characteristics of Ce-ZrO2/CePO4 ceramics. The machined surfaces of ceramics and wear surfaces of drill bits were observed with scanning electron microscope. Material removals and grinding forces were measured. The transgranular fracture of CePO4 grains, intergranular fracture between ZrO2 and CePO4 grains, and ductile deformation of ceramics were observed on Ce-ZrO2/CePO4 machined surfaces. With the increase of CePO4 proportion to composites, drilling material removal rates increases and specific normal grinding forces decreases.There existed rapid wear of conventional metal cutting tool is caused by abrasive wear. The experimental results indicate that the weak interfaces and properties of Ce-ZrO2/CePO4 ceramics have influences on material removal and machinability.

  10. Facile and Mild Strategy to Construct Mesoporous CeO2-CuO Nanorods with Enhanced Catalytic Activity toward CO Oxidation.

    Science.gov (United States)

    Chen, Guozhu; Xu, Qihui; Yang, Ying; Li, Cuncheng; Huang, Taizhong; Sun, Guoxin; Zhang, Shuxiang; Ma, Dongling; Li, Xu

    2015-10-28

    CeO2-CuO nanorods with mesoporous structure were synthesized by a facile and mild strategy, which involves an interfacial reaction between Ce2(SO4)3 precursor and NaOH ethanol solution at room temperature to obtain mesoporous CeO2 nanorods, followed by a solvothermal treatment of as-prepared CeO2 and Cu(CH3COO)2. Upon solvothermal treatment, CuO species is highly dispersed onto the CeO2 nanorod surface to form CeO2-CuO composites, which still maintain the mesoporous feature. A preliminary CO catalytic oxidation study demonstrated that the CeO2-CuO samples exhibited strikingly high catalytic activity, and a high CO conversion rate was observed without obvious loss in activity even after thermal treatment at a high temperature of 500 °C. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and hydrogen temperature-programmed reduction (H2-TPR) analysis revealed that there is a strong interaction between CeO2 and CuO. Moreover, it was found that the introduction of CuO species into CeO2 generates oxygen vacancies, which is highly likely to be responsible for high catalytic activity toward CO oxidation of the mesoporous CeO2-CuO nanorods.

  11. Scintillation properties of selected oxide monocrystals activated with Ce and Pr

    Science.gov (United States)

    Wojtowicz, Andrzej J.; Drozdowski, Winicjusz; Wisniewski, Dariusz; Lefaucheur, Jean-Luc; Galazka, Zbigniew; Gou, Zhenhui; Lukasiewicz, Tadeusz; Kisielewski, Jaroslaw

    2006-01-01

    In the last 10-15 years there has been a significant effort toward development of new, more efficient and faster materials for detection of ionizing radiation. A growing demand for better scintillator crystals for detection of 511 keV gamma particles has been due mostly to recent advances in modern imaging systems employing positron emitting radionuclides for medical diagnostics in neurology, oncology and cardiology. While older imaging systems were almost exclusively based on BGO and NaI:Tl crystals the new systems, e.g., ECAT Accel, developed by Siemens/CTI, are based on recently discovered and developed LSO (Lu 2SiO 5:Ce, Ce-activated lutetium oxyorthosilicate) crystals. Interestingly, despite very good properties of LSO, there still is a strong drive toward development of new scintillator crystals that would show even better performance and characteristics. In this presentation we shall review spectroscopic and scintillator characterization of new complex oxide crystals, namely LSO, LYSO, YAG, LuAP (LuAlO 3, lutetium aluminate perovskite) and LuYAP activated with Ce and Pr. The LSO:Ce crystals have been grown by CTI Inc (USA), LYSO:Ce, LuAP:Ce and LuYAP:Ce crystals have been grown by Photonic Materials Ltd., Scotland (PML is the only company providing large LuAP:Ce crystals on a commercial scale), while YAG:Pr and LuAP:Pr crystals have been grown by Institute of Electronic Materials Technology (Poland). All these crystals have been characterized at Institute of Physics, N. Copernicus University (Poland). We will review and compare results of measurements of radioluminescence, VUV spectroscopy, scintillation light yields, scintillation time profiles and low temperature thermoluminescence performed on these crystals. We will demonstrate that all experiments clearly indicate that there is a significant room for improvement of LuAP, LuYAP and YAG. While both Ce-activated LSO and LYSO perform very well, we also note that LuYAP:Ce, LuAP:Ce and YAG:Pr offer some

  12. Cavitation Erosion Behavior of CrMnN Duplex Stainless Steel in Distilled Water and 3% NaCl Solution

    Institute of Scientific and Technical Information of China (English)

    Suzhen LUO; Yugui ZHENG; Wei LIU; Heming JING; Zhiming YAO; Wei KE

    2003-01-01

    The cavitation erosion (CE) behavior of CrMnN ferrite-austenite duplex stainless steel in distilled water and 3% NaCl solution was investigated by using a magnetostrictive-induced CE facility. The damaged surfaces were observed by scanning electron microscope (SEM). It was found that the CE resistance of CrMnN steel was higher than that of 0Cr13Ni5Mo steel. The mass loss rate of CrMnN steel in distilled water was similar to that in 3% NaCl except at the early stage of CE. The failure mode of ferrite phase was brittle fracture, which had adverse effect on the resistance to CE, while the failure of austenite phase was a ductile failure in CrMnN steel. The excellent resistance to CE was related to the good mechanical properties of austenitic phase and the consumption of CE energy by plastic deformation involving slip and twinning.

  13. 白光LED用LiCaBO3:Ce3+材料发光特性研究%Luminescent characteristics of LiCaBO3:Ce3+phosphor for white LED

    Institute of Scientific and Technical Information of China (English)

    李盼来; 王志军; 杨志平; 郭庆林

    2009-01-01

    采用固相法制备了LiCaBO3:Ce3+发光材料.测得LiCaBO3:Ce3+材料的发射光谱为不对称的单峰宽谱,主峰位于428 nm处;监测428 nm发射峰时所得材料的激发光谱为主峰位于364 nm的宽谱.通过Van Uitert公式证明Ca在LiCaBO3中只存在一种晶体学格位,造成LiCaBO3:Ce3+材料非对称发射的原因是Ce3+离子能级劈裂.研究了Ce3+浓度对LiCaBO3:Ce3+材料发光强度的影响,结果显示随Ce3+浓度的增大,发光强度呈现先增大后减小的趋势,在Ce3+浓度为3%(摩尔分数)时到达峰值,根据Dexter理论,其浓度猝灭机理为电偶极-偶极相互作用.引入Li+,Na+和K+作为电荷补偿剂,发现LiCaBO3:Ce3+材料的发射强度均得到了明显增强.利用InGaN管艺芯(370 nm)激发LiCaBO3:Ce3+材料,呈现很好的蓝白光发射,测得的色坐标为(x=0.287,y=0.290).

  14. Cost objective PLM and CE

    CERN Document Server

    Perry, Nicolas

    2010-01-01

    Concurrent engineering taking into account product life-cycle factors seems to be one of the industrial challenges of the next years. Cost estimation and management are two main strategic tasks that imply the possibility of managing costs at the earliest stages of product development. This is why it is indispensable to let people from economics and from industrial engineering collaborates in order to find the best solution for enterprise progress for economical factors mastering. The objective of this paper is to present who we try to adapt costing methods in a PLM and CE point of view to the new industrial context and configuration in order to give pertinent decision aid for product and process choices. A very important factor is related to cost management problems when developing new products. A case study is introduced that presents how product development actors have referenced elements to product life-cycle costs and impacts, how they have an idea bout economical indicators when taking decisions during t...

  15. Measurement of low-energy Na^+ -- Na total collision rate in an ion--neutral hybrid trap

    CERN Document Server

    Goodman, D S; Kwolek, J M; Blümel, R; Narducci, F A; Smith, W W

    2014-01-01

    We present measurements of the total elastic and resonant charge-exchange ion-atom collision rate coefficient $k_\\mathrm{ia}$ of cold sodium (\\ce{Na}) with optically-dark low energy \\ce{Na+} ions in a hybrid ion-neutral trap. To determine $k_\\mathrm{ia}$, we measured the trap loading and loss from both a \\ce{Na} magneto-optical trap (MOT) and a linear radio frequency quadrupole Paul trap. We found the total rate coefficient to be $7.4 \\pm 1.9 \\times 10^{-8}$ cm$^3$/s for the type I \\ce{Na} MOT immersed within an $\\approx 140$ K ion cloud and $1.10 \\pm 0.25 \\times 10^{-7}$ cm$^3$/s for the type II \\ce{Na} MOT within an $\\approx 1070$ K ion cloud. Our measurements show excellent agreement with previously reported theoretical fully quantal \\textit{ab initio} calculations. In the process of determining the total rate coefficient, we demonstrate that a MOT can be used to probe an optically dark ion cloud's spatial distribution within a hybrid trap.

  16. Raytracing na GPU

    OpenAIRE

    Straňák, Marek

    2011-01-01

    Raytracing je základnou technikou pro vizualizaci trojrozměrných objektů. Cílem práce je demonstrovat možnost implementace sledovaní paprsků pomocí grafického akcelerátoru.  Popíšem základní algoritmus a jeho modifikovanou verzi, která byla implementována pomocí jazyka CUDA C. Výsledný raytracer je optimalizovaný pro dynamické scény. Pro tento účel byla použita akcelerační struktura KD strom, hierarchické obalové tělesa a přenos dat pomocí PBO. Pro realističtější výstupy byla také implementov...

  17. Anchoring noble metal nanoparticles on CeO2 modified reduced graphene oxide nanosheets and their enhanced catalytic properties.

    Science.gov (United States)

    Ji, Zhenyuan; Shen, Xiaoping; Xu, Yuling; Zhu, Guoxing; Chen, Kangmin

    2014-10-15

    The strategy of structurally integrating noble metal, metal oxide, and graphene is expected to offer prodigious opportunities toward emerging functions of graphene-based nanocomposites. In this study, we develop a facile two-step approach to disperse noble metal (Pt and Au) nanoparticles on the surface of CeO2 functionalized reduced graphene oxide (RGO) nanosheets. It is shown that Pt and Au with particle sizes of about 5 and 2nm are well dispersed on the surface of RGO/CeO2. The reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 was used as a model reaction to quantitatively evaluate the catalytic properties of the as-synthesized RGO/Pt/CeO2 and RGO/Au/CeO2 ternary nanocomposites. In such triple-component catalysts, CeO2 nanocrystals provide unique and critical roles for optimizing the catalytic performance of noble metallic Pt and Au, allowing them to express enhanced catalytic activities in comparison with RGO/Pt and RGO/Au catalysts. In addition, a possible mechanism for the enhanced catalytic activities of the RGO/Pt/CeO2 and RGO/Au/CeO2 ternary catalysts in the reduction of 4-NP is proposed. It is expected that our prepared graphene-based triple-component composites, which inherit peculiar properties of graphene, metal oxide, and noble metal, are attractive candidates for catalysis and other applications.

  18. Hydrothermal Preparation and Performance of CeO2-TiO2 Micro-and Nano-composites Deposited on Copper Mesh Film%Cu网负载CeO2-TiO2微纳米复合材料(CeO2-TiO2)/Cu的水热制备与性能

    Institute of Scientific and Technical Information of China (English)

    戴春爱; 高常锐; 冯琳

    2013-01-01

    以Cu网为载体,Ti(OBu)4和Ce(NO3)3·6H2O为原料,Na3PO4·12H2O为矿化剂,采用一步水热法制备了多种不同形貌的Cu网负载CeO2-TiO2微纳米复合材料(CeO2-TiO2)/Cu.采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和紫外-可见漫反射分光光度计(UV-Vis DRS)对材料的形貌、结构及光吸收特性进行了表征,通过测试接触角表征了材料的浸润性.以20 μmol/L亚甲基蓝(MB)溶液为目标降解物,测试了材料在可见光照射下的催化性能.结果表明,制备的TiO2为锐钛矿型,CeO2为方铈矿型;CeO2晶体比TiO2晶体更易负载于Cu网;改变制备过程中Ce(NO3)3·6H2O的用量、Na3 PO4·12H2O浓度、水热反应时间及温度可实现(CeO2-TiO2)/Cu的形貌调控;(CeO2-TiO2)/Cu显示出超亲水性及可见光催化活性.

  19. CeRh3B2: A ferromagnet with anomalously large Ce 5d spin and orbital magnetic moments

    Science.gov (United States)

    Yaouanc, A.; Dalmas de Réotier, P.; Sanchez, J.-P.; Tschentscher, Th.; Lejay, P.

    1998-01-01

    We report a high-energy magnetic-Compton-scattering study performed on the ferromagnet CeRh3B2. This technique solely measures the electron spin magnetic moments. In contrast to a number of Ce intermetallics with nonmagnetic elements, the Ce 5d spin moment is found to be large and parallel to the Ce 4f spin moment. Therefore the Kondo effect does not play a key role for CeRh3B2. The inferred large Ce 5d orbital magnetic moment is a signature of the strong spin-orbit interaction for the Ce 5d band.

  20. The effects of Ce3+ and Ce4+ on the stability of fibroblast growth factor-2

    Science.gov (United States)

    Sun, Liwei; Feng, Hao; Jiang, Rui; Niu, Liping; Song, Yu; Feng, Kai; Qi, Chao

    2010-11-01

    The interaction between tri or tetravalent cerium ions and basic fibroblast growth factor (FGF-2) at 0.1-6: 1 molar ratio under physiological condition was studied by fluorescence and CD spectrum. The different spectra alterations of FGF-2 induced by Ce3+ and Ce4+ showed that Ce3+ and Ce4+ caused different conformational changes of FGF-2 respectively, though both of them destabilized the protein. The instability of FGF-2 in the presence of Ce3+ is involved in the oxidation of its free cystein of protein, but that this treatment nearly does not affect the biological activity. As to Ce4+, it not only induced the conformational changes of protein but also inhibits its activity in a dose-dependent manner, which could be relative to the electrostatic repulsion between Ce4+ and its basic amino acid residues (pI=9.6) or the specific binding of Ce4+ to deprotonated amino acid residues. The interesting results would be helpful to investigate the problem of the stability of proteins.

  1. Measurement of local moment on Ce in CeRh3B2

    Science.gov (United States)

    Devare, S. H.; Devare, H. G.

    1987-03-01

    We have employed the TDPAC technique to measure the paramagnetic enhancement factor β of140Ce in CeRh3B2 in the temperature range 300 K down to 115 K. Our measurements show that above Tc=115 K, the trend for β(T) closely follows that for trivalent cerium.

  2. Investigation on Modification of NaY Zeolite and Its Behaviors in Selective Adsorptive Desulfurization of FCC gasoline

    Institute of Scientific and Technical Information of China (English)

    Zhu Heli; Song Lijuan; Gao Xiang; Wang Hongguo; Zhang Xiaotong; Sun Zhaolin

    2009-01-01

    NaY zeolite was modified with oxalic acid, and Ce(Ⅳ)Y(1) zeolite was obtained via liquid phase ion exchange between the modified NaY zeolite and cerium nitrate. The Ce(Ⅳ)Y(2) zeolite was obtained via liquid phase ion exchange between NaY zeolite and cerium nitrate. The performance of two Y zeolites ICe(Ⅳ)Y(1) and Ce(Ⅳ)Y(2)] was compared through static selective adsorptive desulfurization of FCC gasoline at room tem-perature and normal pressure. The sulfur compounds and contents of the FCC gasoline were analyzed by microcoulometry and GC-SCD chromatogram. The results showed that the effect of adsorptive desulfurization of FCC gasoline achieved by Ce(Ⅳ)Y(1) zeolite was better than that of Ce(Ⅳ)Y(2) zeolite. The rate for adsorp-tive desulfurization of FCC gasoline by Ce(Ⅳ)Y(1) zeolite and Ce(Ⅳ)Y(2) zeolite was 85.0% and 62.4%, respectively. The Ce(Ⅳ)Y(1) zeolite could adsorb DMTs, which could not be adsorbed by Ce(Ⅳ)Y(2) zeolite. The rate of regeneration of extruded Ce(Ⅳ)Y(1)zeolite was 95.5%.

  3. Cyclic voltammetry study of Ce(IV/Ce(III redox couple and Ce(IV-F complex in sulfuric acid medium

    Directory of Open Access Journals (Sweden)

    J. G. He

    2016-10-01

    Full Text Available In this paper the electrochemical behaviors of Ce(IV/Ce(III redox couple and Ce(IV - F complex in sulfuric acid medium were studied by cyclic voltammetry using a platinum electrode. Both of the Ce(IV/Ce(III couple in Ce(IV solution and Ce(IV - F complex is a quasi-reversible process, and gives a linear correlation between the peak potentials and square root of scan rates, showing that the kinetics of the overall process is diffusion controlled. The complexation of cerium(IV and fluoride is favorable for the oxidation of Ce(III. The kinetic parameters such as diffusion coefficients, anodic transfer coefficients and rate constants were studied.

  4. Mercury speciation by CE: an update.

    Science.gov (United States)

    Kubán, Petr; Pelcová, Pavlína; Margetínová, Jana; Kubán, Vlastimil

    2009-01-01

    This review provides an update on mercury speciation by CE. It includes a brief discussion on physicochemical properties, toxicity and transformation pathways of mercury species (i.e. methyl-, ethyl-, phenyl- and inorganic mercury) and outlines recent trends in Hg speciation by CE. CE is presented as a complementary technique to chromatographic separation techniques, especially in cases when speed, high efficiency and low sample volumes are required. The development of suitable sample preconcentration/isolation (sample stacking, ion exchange, liquid-liquid-liquid extraction, dual-cloud point extraction) to achieve low LODs for analysis of trace concentrations of mercury species in real samples is emphasized. Hyphenation of CE to element specific detectors (i.e. electrothermal atomic absorption spectrometry, atomic fluorescence spectrometry, inductively coupled plasma-optical emission spectrometry, inductively coupled plasma-mass spectrometry) is discussed as well as a potential of CE in interaction studies that may provide useful information on interaction of various Hg species with selected bio-macromolecules.

  5. Microstructure of Rh-Ce particles on silica: Interactions between Ce and SiO sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Krause, K.R.; Schmidt, L.D. (Univ. of Minnesota, Minneapolis (United States)); Schabes-Retchkiman, P. (UNAM, Mexico City (Mexico))

    1992-03-01

    The authors have characterized the microstructure of Rh/Ce on SiO{sub 2} after heat treatments in H{sub 2} and O{sub 2} using TEM, HREM, XPS, and EELS, focusing on the very stable structures formed after heating in H{sub 2}. After initial reduction at 600 C, Rh is present as 50- to 100-{angstrom} metal particles while the Ce forms a uniform amorphous film of Ce{sup 3+} on the SiO{sub 2}. After oxidation at 600 C, Rh is oxidized to Rh{sub 2}O{sub 3} and spreads over the SiO{sub 2} surface while Ce forms small patches and large (> 1,000 {angstrom}) particles of crystalline CeO{sub 2}. After reduction of the oxidized microstructure at 600 C, Rh metal returns with a less uniform particle size distribution, while Ce is reduced to Ce{sup 3+} and structures indicating strong interactions between Ce and Si are formed. Upon reduction in the presence of Rh, the CeO{sub 2} particles are reduced to crystalline Ce{sub 2}Si{sub 2}O{sub 7}. The Ce silicate nucleates at Rh particles and spreads over the support as large thin single-crystal patches. After reoxidation at 650 C, both Ce silicate and CeO{sub 2} were identified using EELS chemical shifts, indicating that the crystalline silicate, once formed, is stable in oxygen. Ce on SiO{sub 2}also showed interaction between Ce and Si, but no crystalline species formed after reduction and only small crystalline CeO{sub 2} particles formed after oxidation. Thus, the formation of the Ce silicate and the oxidation of Ce to CeO{sub 2} are catalyzed by Rh. This work represents the first direct evidence for the formation of a Ce silicate in this system.

  6. Ensuring complete absence of Ce(IV) and measurement of the stability constant of the fluoride complex of Ce(III)

    Energy Technology Data Exchange (ETDEWEB)

    Sawant, R.M.; Chaudhuri, N.K.; Ramakumar, K.L. [Fuel Chemistry Division, Bhabha Atomic Research Centre, Trombay, 400 085 Mumbai (India)

    2001-01-05

    Literature survey revealed a wide variation in the measured stability constant values of the aqueous fluoride complexes of trivalent cerium. This could be due to inadequate care for full conversion and maintenance of the oxidation state of cerium to trivalent state. In the present work quinhydrone has been used to ensure complete absence of Ce(IV) and the stability constant of CeF{sup 2+} in 1 M NaClO{sub 4} has been measured potentiometrically using a fluoride ion selective electrode. Log {beta}{sub 1} obtained in this work was 2.936{+-}0.024 and fitted well with the general trend of stability constants of the lanthanide (rare earths) fluorides in aqueous solution.

  7. Liquid-core waveguide in CE.

    Science.gov (United States)

    Okada, Tetsuo

    2007-10-01

    Liquid-core waveguide (LCW) brings about several advantages in CE. This review discusses some aspects of fundamental and practical importance involved in this method. Sensitivity in absorption and fluorescence detection is in general improved by more than one order of magnitude over usual crossbeam detection arrangements; the improvements come from the long light path in absorption detection and low light scattering in fluorescence detection. Versatile instrumental arrangements are another advantage of LCW in CE, leading to several detection schemes, some of which provide information that is not gained by usual capillary-end crossbeam detection, e.g. whole-capillary imaging, simultaneous monitoring of multicapillary separation, and kinetic evaluation. The high potential and perspectives of LCW in CE are discussed based on the state-of-the-art developments.

  8. New approaches in sensitive chiral CE.

    Science.gov (United States)

    Sánchez-Hernández, Laura; Guijarro-Diez, Miguel; Marina, María Luisa; Crego, Antonio L

    2014-01-01

    CE has shown to have a big potential for chiral separations, with advantages such as high efficiency, high resolution, and low sample and reagents consumption. Nevertheless, when UV detection is employed, CE has some drawbacks, especially the low sensitivity obtained due to the short optical path length. Notwithstanding, sensitivity improvements can be achieved when different approaches are employed, such as sample treatment strategies (off-line or on-line), in-capillary sample preconcentration techniques, and/or alternative detection systems to UV-Vis (such as fluorescence, conductimetry, electrochemiluminiscence, MS, etc.). This article reviews the most recent methodological and instrumental advances reported from June 2011 to May 2013 for enhancing the sensitivity in chiral analysis by CE. The sensitivity achieved for the enantioseparated analytes and the applications carried out using the developed methodologies are also summarized.

  9. Metamagnetism in Ce(Ga,Al)2

    Indian Academy of Sciences (India)

    K G Suresh; S Radha; A K Nigam

    2002-05-01

    Effect of Al substitution on the magnetic properties of Ce(Ga1-Al)2 ( = 0, 0.1 and 0.5) system has been studied. The magnetic state of CeGa2 is found to be FM with a C of 8 K, whereas the compounds with =0.1 and 0.5 are AFM and possess N of about 9 K. These two compounds undergo metamagnetic transition and the critical fields are about 1.2 T and 0.5 T, respectively at 2 K. These variations are explained on the basis of helical spin structure in these compounds.

  10. Laser altimeter of CE-1 payloads system

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The design and operation of the Laser Altimeter of CE-1 Payloads System are presented in this paper.The paper includes the design of the system and spacecraft-level laser,the description of the emitting-system and receiving system,and the testing of the laser altimeter.The CE-1 laser altimeter is the first Chinese deep-space probe using a laser.It has one beam and operates at 1 Hz,with a nominal accuracy of 5 m.The laser altimeter has operated successfully in lunar orbit since November 28,2007.It has obtained 9120 thousand data values about the lunar altitude.

  11. Neutron scattering from -Ce at epithermal neutron energies

    Indian Academy of Sciences (India)

    A P Murani

    2008-10-01

    Neutron scattering data, using neutrons of incident energies as high as 2 eV, on -Ce and -Ce-like systems such as CeRh2, CeNi2, CeFe24, CeRu2, and many others that point clearly to the substantially localized 4f electronic state in these systems are reviewed. The present interpretation is contrary to the widely held view that the 4f electrons in these systems form a narrow itinerant electron 4f band.

  12. Impact of Precipitants on the Structure and Properties of Fe-Co-Ce Composite Catalysts

    Directory of Open Access Journals (Sweden)

    Yongli Zhang

    2016-01-01

    Full Text Available Fe-Co-Ce composite catalysts were prepared by coprecipitation method using CO(NH22, NaOH, NH4HCO3, and NH3·H2O as precipitant agents. The effects of the precipitant agents on the physicochemical properties of the Fe-Co-Ce based catalysts were investigated by SEM, TEM, BET, TG-DTA, and XRD. It was found that the precipitant agents remarkably influenced the morphology and particle size of the catalysts and affected the COD removal efficiency, decolorization rate, and pH of methyl orange for catalytic wet air oxidation (CWAO. The specific surface area of the Fe-Co-Ce composite catalysts successively decreased in the order of NH3·H2O, NH4HCO3, NaOH, and CO(NH22, which correlated to an increasing particle size that increased for each catalyst. For the CWAO of a methyl orange aqueous solutions, the effects of precipitant agents NH3·H2O and NaOH were superior to those of CO(NH22 and NH4HCO3. The catalyst prepared using NH3·H2O as the precipitant agent was mostly composed of Fe2O3, CoO, and CeO2. The COD removal efficiency of methyl orange aqueous solution for NH3·H2O reached 92.9% in the catalytic wet air oxidation. Such a catalytic property was maintained for six runs.

  13. Automated sample preparation for CE-SDS.

    Science.gov (United States)

    Le, M Eleanor; Vizel, Alona; Hutterer, Katariina M

    2013-05-01

    Traditionally, CE with SDS (CE-SDS) places many restrictions on sample composition. Requirements include low salt content, known initial sample concentration, and a narrow window of final sample concentration. As these restrictions require buffer exchange for many sample types, sample preparation is often tedious and yields poor sample recoveries. To improve capacity and streamline sample preparation, an automated robotic platform was developed using the PhyNexus Micro-Extractor Automated Instrument (MEA) for both the reduced and nonreduced CE-SDS assays. This automated sample preparation normalizes sample concentration, removes salts and other contaminants, and adds the required CE-SDS reagents, essentially eliminating manual steps during sample preparation. Fc-fusion proteins and monoclonal antibodies were used in this work to demonstrate benefits of this approach when compared to the manual method. With optimized conditions, this application has demonstrated decreased analyst "hands on" time and reduced total assay time. Sample recovery greater than 90% can be achieved, regardless of initial composition and concentration of analyte.

  14. HIGH-SPIN STATES IN CE-131

    NARCIS (Netherlands)

    PALACZ, M; SUJKOWSKI, Z; NYBERG, J; BACELAR, J; JONGMAN, J; HESSELINK, W; NASSER, J; PLOMPEN, A; WYSS, R

    1991-01-01

    Gamma ray spectra from the Sn-117(O-18, 4n)131Ce reaction have been studied with the NORDBALL array of 15 Compton-suppressed Ge detectors. States up to I = 51/2 h, E almost-equal-to 8 MeV are populated. Observed bands are interpreted in terms of quasiparticle configurations.

  15. Search for pressure-induced superconductivity in CeFeAsO and CeFePO iron pnictides

    Energy Technology Data Exchange (ETDEWEB)

    Zocco, D. A. [University of California, San Diego; Baumbach, R. E. [University of California, San Diego; Hamlin, J. J. [University of California, San Diego; Janoschek, M. [University of California, San Diego; Lum, I. K. [University of California, San Diego; McGuire, Michael A [ORNL; Safa-Sefat, Athena [ORNL; Sales, Brian C [ORNL; Jin, Rongying [ORNL; Mandrus, David [ORNL; Jeffries, J. R. [Lawrence Livermore National Laboratory (LLNL); Weir, S. T. [Lawrence Livermore National Laboratory (LLNL); Vohra, Y. K. [University of Alabama, Birmingham; Maple, M. B. [University of California, San Diego

    2011-01-01

    The CeFeAsO and CeFePO iron pnictide compounds were studied via electrical transport measurements under high pressure. In CeFeAsO polycrystals, the magnetic phases involving the Fe and Ce ions coexist for hydrostatically applied pressures up to 15 GPa, and with no signs of pressure-induced superconductivity up to 50 GPa for the less hydrostatic pressure techniques. For the CeFePO single crystals, pressure further stabilizes the Kondo screening of the Ce 4f-electron magnetic moments.

  16. Correlated electronic structure of CeN

    Energy Technology Data Exchange (ETDEWEB)

    Panda, S.K., E-mail: swarup.panda@physics.uu.se [Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala (Sweden); Di Marco, I. [Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala (Sweden); Delin, A. [Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala (Sweden); KTH Royal Institute of Technology, School of Information and Communication Technology, Department of Materials and Nano Physics, Electrum 229, SE-164 40 Kista (Sweden); KTH Royal Institute of Technology, Swedish e-Science Research Center (SeRC), SE-100 44 Stockholm (Sweden); Eriksson, O., E-mail: olle.eriksson@physics.uu.se [Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala (Sweden)

    2016-04-15

    Highlights: • The electronic structure of CeN is studied within the GGA+DMFT approach using SPTF and Hubbard I approximation. • 4f spectral functions from SPTF and Hubbard I are coupled to explain the various spectroscopic manifestations of CeN. • The calculated XPS and BIS spectra show good agreement with the corresponding experimental spectra. • The contribution of the various l-states and the importance of cross-sections for the photoemission process are analyzed. - Abstract: We have studied in detail the electronic structure of CeN including spin orbit coupling (SOC) and electron–electron interaction, within the dynamical mean-field theory combined with density-functional theory in generalized gradient approximation (GGA+DMFT). The effective impurity problem has been solved through the spin-polarized T-matrix fluctuation-exchange (SPTF) solver and the Hubbard I approximation (HIA). The calculated l-projected atomic partial densities of states and the converged potential were used to obtain the X-ray-photoemission-spectra (XPS) and Bremstrahlung Isochromat spectra (BIS). Following the spirit of Gunnarsson–Schonhammer model, we have coupled the SPTF and HIA 4f spectral functions to explain the various spectroscopic manifestations of CeN. Our computed spectra in such a coupled scheme explain the experimental data remarkably well, establishing the validity of our theoretical model in analyzing the electronic structure of CeN. The contribution of the various l-states in the total spectra and the importance of cross sections are also analyzed in detail.

  17. Valence state of Ce and the magnetism in CeRh3B2

    Science.gov (United States)

    Malik, S. K.; Umarji, A. M.; Shenoy, G. K.; Montano, P. A.; Reeves, M. E.

    1985-04-01

    The compound CeRh3B2 orders magnetically with a high Curie temperature (TC) of 115 K but with a low moment of only absorption edge measurements show a dominant absorption peak at the energy corresponding to trivalent cerium. Magnetic studies on the compounds Ce(Rhsub1-xTsubx)sub3Bsub2 with T=Ru and Os reveal that the magnetic state is very rapidly broken up with the replacement of Rh by Ru and Os. These results along with the observation of a high TsubC in CeRhsub3Bsub2 suggest that magnetism in this compound arises from a strong hybridization of nearly localized or slightly delocalized Ce 4f electrons with conduction electrons. The small moment may be due to a Kondo-type interaction coupled with crystal-field effects.

  18. Mechanism of (NH{sub 4})S{sub 2}O{sub 8} to enhance the anti-corrosion performance of Mo-Ce inhibitor on X80 steel in acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yanhua [School of Materials Science and Engineering, Southwest Petroleum University, Chengdu 610500 (China); Zhuang, Jia, E-mail: zj-656@163.com [School of Materials Science and Engineering, Southwest Petroleum University, Chengdu 610500 (China); Zeng, Xianguang [Material Corrosion and Protection Key Laboratory of Sichuan Province, Zigong 643000 (China); Institute of Materials and Chemical Engineering, Sichuan University of Science and Engineering, Zigong 643000 (China)

    2014-09-15

    Highlights: • The 1000 mg/L Na{sub 2}MoO{sub 4} and 500 mg/L Ce(NO{sub 3}){sub 3} has best synergistic effect. • The (NH{sub 4}){sub 2}S{sub 2}O{sub 8} made the valence transformation of cerium (Ce{sup 3+} → Ce{sup 4+}) come true. • The anti-corrosion performance of Mo-Ce inhibitor was improved by (NH{sub 4}){sub 2}S{sub 2}O{sub 8}. • The coordination ability of inhibitor complexes was improved by (NH{sub 4}){sub 2}S{sub 2}O{sub 8}. • The bonding force and adsorption between inhibitor and steel surface was enhanced. - Abstract: Ce(NO{sub 3}){sub 3} and Na{sub 2}MoO{sub 4} are adopted to form (Mo-Ce) composite corrosion inhibitor in allusion to the corrosion problem of steel in acidic conditions. The experimental results showed that the anticorrosion effects were enhanced and the inhibition efficiencies were increased by (NH{sub 4}){sub 2}S{sub 2}O{sub 8}. The reason of enhancement is the increase of coordination bonds amount between Ce{sup 4+} and MoO{sub 4}{sup 2−}, the augment of combining sites of interface between anti-corrosion film and steel, and the reinforce of adsorption caused by the transformation of Ce{sup 3+} to Ce{sup 4+} by oxidants. The process and conditions for transformation of Ce{sup 3+} to Ce{sup 4+} and formation of complexes are discussed. The related thermodynamic and kinetic parameters are calculated and the possibility for (NH{sub 4}){sub 2}S{sub 2}O{sub 8} to improve the performance of Mo-Ce corrosion inhibitor is proved.

  19. Effect of CeO2 on the Property of Zn-Ni/CeO2 Composite Coating%CeO2对Zn-Ni/CeO2复合镀层的影响

    Institute of Scientific and Technical Information of China (English)

    郑振; 李宁; 黎德育; 孟繁宇

    2012-01-01

    采用电沉积方法,通过向镀液中加入不同粒径的CeO2颗粒,制得Zn-Ni/微米CeO2复合镀层和Zn-Ni/纳米CeO2复合镀层,研究了CeO2粒子的大小和加入量对镀层微观形貌、相组成、CeO2在镀层中的复合量以及镀层耐蚀性的影响.结果表明:大量加入CeO2,可使镀层呈现块状的“饼干”结构,并能提高镀层的耐蚀性,此外还可以抑制Ni的沉积,加入10 g/L纳米CeO2时,镀层的合金相主要为Ni2Zn11相,其它Zn-Ni合金相则较少;相比之下,在提高镀层CeO2复合量方面,微米级CeO2效果较好,在提高镀层耐蚀性方面,纳米级CeO2的效果较好.%The Ni-Zn/micro-CeO2 composite material and Ni-Zn/nano-CeO2 composite material were produced by electrodeposition method through adding micro- and nano-CeO2 particles in the Zn-Ni plating bath. The effects of the diameter and the concentration of the CeO2 particles on the microtopography, phase component, CeO2 content and the corrosion resistance of the Ni-Zn coating were studied. The result shows that when the concentration of the CeO2 particles is high, the Ni deposition is inhibited; The composite coatings are characterized with laminate morphology with good corrosion resistance. When the concentration of the nano-CeO2 particles is 10 g/L, the major alloy phase is Ni2Zn11. Compared with the nano-composite coating, the CeO2 content is larger in the micro-CeO2 composite coating. But the corrosion resistance of the nano-CeO2 composite coating is larger than that of the micro-CeO2 ones.

  20. INCA-CE project: status and results

    Science.gov (United States)

    Strauss, Franziska; Meirold-Mautner, Ingo; Bica, Benedikt; Kann, Alexander; Wang, Yong

    2013-04-01

    Every year, Central Europe (CE) is affected by weather extremes challenging civil protection authorities, hydrologists and road maintenance services to timely warnings. Within the INCA-CE project (Integrated Nowcasting through Comprehensive Analysis in Central Europe; http://www.inca-ce.eu) which is supported by the European Regional Development Fund a deepened transnational cooperation between meteorological/hydrological services and three application areas is established. This guarantees for both enhancements of meteorological products in the sense of end-user friendliness, and standardized information exchange across borders. At present, INCA-CE is the only project throughout the world which connects cooperation to such an extent with respect to its transnational and multidisciplinary framework (in the meanwhile it has been chosen as World Weather Research Programme/Forecast Demonstration Project by the World Meteorological Organization). Key partners from eight countries (from national meteorological/hydrological services and the three different application areas) accept the challenge to work on standardization and harmonization tools. Therefore, the INCA nowcasting system - developed at the Austrian weather service (ZAMG) in the 1990ies - has been implemented at all CE meteorological/hydrological services and is advanced and refined to the specific user needs to (i) provide high quality nowcasting products which are standardized and harmonized across borders, (ii) improve information chains from models to warnings and protection measures in case of disaster, and (iii) make the public and stakeholders more familiar with meteorological products. However, the potential to achieve these listed improvements is only possible through the intense transnational and multidisciplinary cooperation, because for one institution and one country alone it would be impossible to cope with all the necessary tasks. In this presentation the status and results of the INCA-CE

  1. Local character of the highest antiferromagnetic Ce-system CeTi{1-x}Sc{x} Ge

    OpenAIRE

    2014-01-01

    The highest antiferromagnetic (AFM) temperature in Ce based compounds has been reported for CeScGe with Tn=47K, but its local or itinerant nature was not deeply investigated yet. In order to shed more light into this unusually high ordering temperature we have investigated structural, magnetic, transport and thermal properties of CeTi{1-x}Sc{x}Ge alloys within the range of stability of the CeScSi-type structure: 0.25

  2. Hydrothermal synthesis of Ce: LuzSiO5 scintillator powders

    Institute of Scientific and Technical Information of China (English)

    YUN; Ping; SHI; Ying

    2009-01-01

    The synthesis of cerium-doped lutetium oxyorthosilicate (LSO) polycrystalline powders was investigated by a hydrothermal proc-ess. The precursor was obtained by the hydrothermal reaction of Lu(NO3)3 with Na2SiO3 at 200 ℃ for 10 h by using urea as precipitator, fol-lowed by a calcination uader proper temperatures. The results of XRD indicated that the precursor was crystallized into A-type LSO phase at 1000 ℃, and transfetrred to B-type LSO phase when temperature was raised above 1050 ℃. After being heated at 1250 ℃ for 2 h, single phase of B-type LSO powder was synthesized with homogeneous distribution of particle size ranging from 200 to 300 nm. The photolumi-nescence spectrum of as-synthesized LSO: Ce powders showed a typical broad emission peak centered at 404 nm, corresponding to the 5d1-4f transition of Ce3+.

  3. Turquie, Grèce : un passé commun, des nouvelles perspectives

    OpenAIRE

    Akgönül, Samim; Bertrand, Gilles; Bilici, Faruk; Dalègre, Joëlle; Drettas, Georges; Sawas, Stéphane; Tonnet, Henri; YÉRASIMOS, Stéphane; Zerouali, Basma

    2013-01-01

    Sans être naïfs sur les questions aussi importantes que le contentieux en mer Égée, le problème chypriote, la question des minorités, la confrontation des nationalismes, l’instrumentalisation de l'histoire, l’utilisation des différends comme outil politique interne, avec ce numéro spécial « Turquie et Grèce : un passé commun, des nouvelles perspectives », nous avons voulu délibérément mettre l’accent sur la complémentarité et la communauté culturelle entre Grecs et Turcs, bien plus encore que...

  4. Laser properties of yag: Nd, Cr, Ce

    Science.gov (United States)

    Kvapil, J.; Kvapil, Jos; Perner, B.; Kubelka, J.; Mánek, B.; Kubeček, V.

    1984-06-01

    Transient absorption of a long lifetime (≧ 20 s) of YAG: Nd is typical of pure material. It is the main reason of thermal deformation of the laser rods accompanied with power decreases at higher CW input. It may be prevented by an admixture of Fe, Ti or Cr. Using a small admixture (≦ 10-3 wt.%) of Ti or Cr the energy transfer among Nd ions and the gain coefficient may be increased. Cr in a higher concentration absorbs the pumping light and serves as earlier described coactivator (sensitizer) only. Fe impurity fully prevents any increase of the gain of YAG: Nd containing Ti or Cr and causes slow but irreversible degradation of the active parameters. Ce favourably modifies properties of YAG: Nd, Cr. YAG: Nd, Cr, Ce free of iron impurity is advisable active material for powerfull CW lasers.

  5. Ce qui se passe dans tes doigts

    OpenAIRE

    Quintans, Santiago; Lähdeoja, Otso

    2010-01-01

    Une question simple, c’est quoi la guitare électrique ? Claude Pavy : C’est une planche avec un manche, des cordes qui font tzing, des micros qui captent tzing, et après on fait joujou avec ça. La guitare électrique c’est d’abord le son. Je dis souvent à mes élèves : « la guitare, cela ne m’intéresse pas ». Alors évidemment, ils me regardent avec des yeux ronds, et ils me disent, « T’es guitariste ? » Oui, mais la guitare en elle-même, cela ne m’intéresse pas. Ce qui m’intéresse, c’est ce qu...

  6. Cerium intermetallics CeTX. Review III

    Energy Technology Data Exchange (ETDEWEB)

    Poettgen, Rainer; Janka, Oliver [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Chevalier, Bernard [Bordeaux Univ., Pessac (France). Inst. de Chimie de la Matiere Condensee de Bordeaux

    2016-05-01

    The structure-property relationships of CeTX intermetallics with structures other than the ZrNiAl and TiNiSi type are systematically reviewed. These CeTX phases form with electron-poor and electron-rich transition metals (T) and X = Mg, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, Sb, and Bi. The review focusses on the crystal chemistry, the chemical bonding peculiarities, and the magnetic and transport properties. Furthermore {sup 119}Sn Moessbauer spectroscopic data, high-pressure studies, hydrogenation reactions and the formation of solid solutions are reviewed. This paper is the third of a series of four reviews on equiatomic intermetallic cerium compound [Part I: R. Poettgen, B. Chevalier, Z. Naturforsch. 2015, 70b, 289; Part II: R. Poettgen, B. Chevalier, Z. Naturforsch. 2015, 70b, 695].

  7. The CeDRES data portal

    Science.gov (United States)

    Albert-Aguilar, Alexandre; Delmotte, Pauline; André, François; Brissebrat, Guillaume; Canonici, Jean-Christophe; Piguet, Bruno

    2016-04-01

    SAFIRE is the French facility dedicated to airborne measurement for environmental research. The SAFIRE steering committee decided that access to its archives should be improved. If certain data, including recent campaigns, are available online, access to them is difficult for users because these data are dispersed in as many data portals as campaigns. Most of projects are not able to keep medium to long term online access to their database. Therefore, many airborne data, particularly the oldest, are not available online, stored on media whose sustainability is not guaranteed. SAFIRE also decided to identify old data stored in Meudon (France) on paper and hard media and to rescue with the help of an archivist. At the same time, the development of a centralized digital archive - containing data collected with the Fokker - 27 " ARAT " and Merlin IV aircraft - associated to a web portal was given to SEDOO. The first part of the project consisted in modelling the database. The second part, still in progess, was the development of the CeDRES (Centre de Données aéRoportées & SAFIRE) portal (http://cedres.sedoo.fr) which is responsive and bilingual (French and English) ; and metadata standardization (iso 19115). The main objectives of this project are data preservation and open data access. A first test version of CeDRES portal will be release in mid-February 2016. And operational version is planned for summer 2016. In the future, CeDRES portal will be able to receive and to distribute metadata and data of aircraft currently in service (FALCON-20, ATR-42 and PiperAztec-23). The interoperability implementation and data homogenization are planned in the medium term. The CeDRES portal is part of the French atmospheric chemistry data center AERIS (http://www.aeris-data.fr). Every scientist is invited to browse the catalog and use CEDRES data. Feel free to contact cedres-contact@sedoo.fr for any question.

  8. Structure and antibacterial activity of Ce~(3+) exchanged montmorillonites

    Institute of Scientific and Technical Information of China (English)

    OUYANG Yousheng; XIE Yushan; TAN Shaozao; SHI Qingshan; CHEN Yiben

    2009-01-01

    Four kinds of Ce~(3+) exchanged montmorillonites(Ce/MMTs) were prepared by an ion-exchange reaction, and characterized with energy dispersive X-ray analysis (EDX), X-ray difference (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron micros-copy (SEM). The surface properties and antibacterial activity of Ce/MMTs were also investigated. The chemical compositions of Ce/MMTs were determined, and the cerium of Ce/MMTs was confirmed to be present as trivalent cerium state. The d001 basal spacings of Ce/MMTs were enlarged with the enhancement of the cerium contents, and the particles were formed with irregular shape. On increasing the Ce con-tents of Ce/MMTs, the special surface areas were decreased, but the total pore volumes and the average pore sizes were increased. The anti-bacterial activity of Ce/MMTs is increased with increasing the cerium contents, and 1.5g/L of Ce/MMT-3 containing 11.46wt.% of curium could remove all the Staphylococcus aureus and more than 99.9% of the Escherichia coli within 24.0 h of contact. Moreover, Ce/MMTs dis-played bactericidal activity.

  9. Preparation and characterization of CNT-CeO2 nanocomposite

    Science.gov (United States)

    Kaur, Jasmeet; Anand, Kanika; Singh, Ravi Chand

    2015-06-01

    This paper reports decoration of CeO2 nanoparticles on multi-walled carbon nanotubes through a reflux process in which Ce (NO3) 3.6H2O serves as precursor and hydrazine hydrate (N2H4.H2O) as reducing agent. Successful deposition of cubic fluorite CeO2 nanoparticles onto multi-walled carbon nanotubes has been confirmed by x-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy (EDS). It was found that CeO2 nanoparticles formed in the presence of CNTs were larger as compared to pure CeO2 nanoparticles. Raman analysis showed that CeO2 induced a decrease in the size of the carbon grain in the CNTs. A red shift from 460 cm-1 to 463 cm-1 for F2g mode of CeO2 has also been observed in Raman spectra of CNT- CeO2 nanocomposite as compared to pure CeO2. The CeO2 coated multi-wall carbon nanotubes (CNT-CeO2) nanocomposite would be a promising candidate for practical applications such as catalysis, sensing and power source applications.

  10. [Effects of Arbuscular Mycorrhizal Fungi on the Growth and Ce Uptake of Maize Grown in Ce-contaminated Soils].

    Science.gov (United States)

    Wang, Fang; Guo, Weil; Ma, Peng-kun; Pan, Liang; Zhang, Jun

    2016-01-15

    A greenhouse pot experiment was conducted to investigate the effects of arbuscular mycorrhizal (AM) fungi Glomus aggregatum (GA) and Funneliformis mosseae (FM) on AM colonization rate, biomass, nutrient uptake, C: N: P stoichiometric and Ce uptake and transport by maize (Zea mays L.) grown in soils with different levels of Ce-contaminated (100, 500 and 1000 mg x kg(-1)). The aim was to provide basic data and technical support for the treatment of soils contaminated by rare earth elements. The results indicated that symbiotic associations were successfully established between the two isolates and maize, and the average AM colonization rate ranged from 7. 12% to 74.47%. The increasing concentration of Ce in soils significantly decreased the mycorrhizal colonization rate, biomass, nutrition contents and transport rate of Ce from root to shoot of maize, and significantly increased C: P and N: P ratios and Ce contents in shoot and root of maize. Both AM fungi inoculations promoted the growth of maize, but the promoting role of FM was more significant than that of GA in severe Ce-contaminated soils. There were no significant differences in the growth of maize between two AM fungi in mild and moderate Ce-contaminated soils. Inoculation with AM fungi significantly improved nutritional status of maize by increasing nutrient uptake and decreasing C: N: P ratios. GA was more efficient than FM in enhancing nutrient uptake in mild and moderate Ce-contaminated soils, while FM was more efficient in severe Ce-contaminated soils. Moreover, inoculation with AM fungi significantly increased Ce contents of shoot and root in mild Ce-contaminated soils, but had no significant effect on Ce contents of maize in moderate and severe Ce-contaminated soils, and promoted the transport of Ce from root to shoot. The experiment demonstrates that AM fungi can alleviate toxic effects of Ce on plants and have a potential role in the phytoremediation of soils contaminated by rare earth elements.

  11. Water Dissociation on CeO2(100) and CeO2(111) Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Mullins, David R [ORNL; Albrecht, Peter M [ORNL; Chen, Tsung-Liang [ORNL; Calaza, Florencia C [ORNL; Biegalski, Micahel [Oak Ridge National Laboratory (ORNL); Christen, Hans [Oak Ridge National Laboratory (ORNL); Overbury, Steven {Steve} H [ORNL

    2012-01-01

    This study reports and compares the adsorption and dissociation of water on oxidized and reduced CeO{sub 2}(100) and CeO{sub 2}(111) thin films. Water adsorbs dissociatively on both surfaces. On fully oxidized CeO{sub 2}(100) the resulting surface hydroxyls are relatively stable and recombine and desorb as water over a range from 200 to 600 K. The hydroxyls are much less stable on oxidized CeO{sub 2}(111), recombining and desorbing between 200 and 300 K. Water produces 30% more hydroxyls on reduced CeO{sub 1.7}(100) than on oxidized CeO{sub 2}(100). The hydroxyl concentration increases by 160% on reduced CeO{sub 1.7}(111) compared to oxidized CeO{sub 2}(111). On reduced CeO{sub 1.7}(100) most of the hydroxyls still recombine and desorb as water between 200 and 750 K. Most of the hydroxyls on reduced CeO{sub 1.7}(111) react to produce H{sub 2} at 560 K, leaving O on the surface. A relatively small amount of H{sub 2} is produced from reduced CeO{sub 1.7}(100) between 450 and 730 K. The differences in the adsorption and reaction of water on CeO{sub X}(100) and CeO{sub X}(111) are attributed to different adsorption sites on the two surfaces. The adsorption site on CeO{sub 2}(100) is a bridging site between two Ce cations. This adsorption site does not change when the ceria is reduced. The adsorption site on CeO{sub 2}(111) is atop a single Ce cation, and the proton is transferred to a surface O in a site between three Ce cations. When the CeO{sub X}(111) is reduced, vacancy sites are produced which allows the water to adsorb and dissociate on the 3-fold Ce cation sites.

  12. Thermally Stable Hierarchical Nanostructures of Ultrathin MoS2 Nanosheet-Coated CeO2 Hollow Spheres as Catalyst for Ammonia Decomposition.

    Science.gov (United States)

    Gong, Xueyun; Gu, Ying-Qiu; Li, Na; Zhao, Hongyang; Jia, Chun-Jiang; Du, Yaping

    2016-04-18

    MoS2 ultrathin nanosheet-coated CeO2 hollow sphere (CeO2@MoS2) hybrid nanostructures with a 3D hierarchical configuration were successfully constructed from a facile two-step wet chemistry strategy: first, CeO2 formed on a silica core which served as a template and was subsequently removed by NaOH solution to attain hollow spheres, and then few-layered ultrathin MoS2 nanosheets were deposited on the CeO2 hollow spheres through a hydrothermal process. As a proof of concept application, the as-prepared CeO2@MoS2 hybrid nanostructures were used as catalytic material, which exhibited enhanced catalytic activity in ammonia decomposition for H2 production at high temperature. It was demonstrated that, even with a structural transformation from MoS2 to MoNx under harsh conditions of ammonia decomposition at high temperature (700 °C), the 3D hierarchical nanostructures of the CeO2@MoNx were well kept, indicating the important role of the CeO2 support.

  13. Spectral Properties and Energy Transfer between Ce(3+) and Yb(3+) in the Ca3Sc2Si3O12 Host: Is It an Electron Transfer Mechanism?

    Science.gov (United States)

    Zhou, Lei; Tanner, Peter A; Ning, Lixin; Zhou, Weijie; Liang, Hongbin; Zheng, Lirong

    2016-07-21

    The downshifting from Ce(3+) blue emission to Yb(3+) near-infrared emission has been studied in the garnet host Ca2.8-2xCe0.1YbxNa0.1+xSc2Si3O12 (x = 0-0.36). The downshifting does not involve quantum cutting, but one incident blue photon is transferred from Ce(3+) to Yb(3+) with an energy transfer efficiency up to 90% when x = 0.36 for the Yb(3+) dopant ion. For x ≤ 0.15, a multiphonon-assisted electric dipole-electric quadrupole mechanism of energy transfer dominates, while for the highest concentration of Yb(3+) employed, the electron transfer mechanism is confirmed. A temperature-dependent increase of the Ce(3+) → Yb(3+) energy transfer rate does not exclusively indicate the electron transfer mechanism. The application of the material to solar energy conversion is indicated.

  14. A comparison between Ce(III) and Ce(IV) ions in photocatalytic degradation of organic pollutants

    Institute of Scientific and Technical Information of China (English)

    程强; 施薇; 段炼; 孙彬哲; 李晓霞; 徐爱华

    2015-01-01

    Nano cerium oxides are efficient photocatalysts for pollutants degradation with highly dispersed Ce(III) ions as the sug-gested active species to promote the reaction, while Ce(IV) species do not behave as a catalyst. In this paper, to understand the mechanism of Ce-based photocatalysts, we studied the comparison of simple cerium ions, Ce(III) and Ce(IV) in aqueous solution for organic pollutants degradation under UV irradiation. Orange II (AOII), methyl orange, andp-nitrophenol were selected as the target pollutants. The formation and contribution of reactive oxygen species, the kinetics of Ce(IV) photoreduction and Ce(III) photooxida-tion, and the influence of solution pH were investigated in detail. It was found that at low pH Ce(IV) ions showed a higher activity for hydroxyl radicals production and AOII degradation than Ce(III) ions, which could be attributed to its fast reduction rate to Ce(III). However, its activity dramatically decreased when solution pH increased, and was also strongly influenced by the type of pollutants; while Ce(III) exhibited high degradation efficiency of all the tested pollutants over a wide pH range.

  15. Highly efficient catalytic reductive degradation of various organic dyes by Au/CeO₂-TiO₂ nano-hybrid

    Indian Academy of Sciences (India)

    PRANJAL SAIKIA; ABU T MIAH; PARTHA P DAS

    2017-01-01

    Highly improved catalytic reductive degradation of different organic dyes, in the presence of excess NaBH₄ over Au/CeO₂-TiO₂ nano-hybrid as the catalyst is reported in this study. CeO₂-TiO₂ nanocomposite was prepared by a facile co-precipitation method using ultra-high dilute aqueous solutions. Small amount of Au (only 1 wt%) was loaded onto the nanocomposite material by deposition-precipitation with urea (DPU) method to fabricate the ternary Au/CeO₂-TiO₂ nano-hybrid. The catalysts were characterized by the representative techniques like XRD, BET surface area, ICP-AES, UV-Vis diffuse reflectance spectroscopy, TEM and XPS. The Au/CeO₂-TiO₂ nano-hybrid along with NaBH₄ exhibited remarkable catalytic activities towards all the probed dyes, namely Methylene Blue, Methyl Orange, Congo Red, Rhodamine B and Malachite Green, with a degradation efficiency of ~100% in a short reaction time. The degradation reaction followed pseudo-first-order kinetics with respect to the concentration of the dye. Different parameters that affect the rate of the reaction are discussed. A plausible mechanism for methylene blue degradation has also been proposed.

  16. Enhanced time response of 1-in. LaBr{sub 3}(Ce) crystals by leading edge and constant fraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Vedia, V., E-mail: mv.vedia@ucm.es [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, ES-28040 Madrid (Spain); Mach, H. [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, ES-28040 Madrid (Spain); National Centre for Nuclear Research, Division for Nuclear Physics, BP1, PL-00-681 Warsaw (Poland); Fraile, L.M.; Udías, J.M. [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, ES-28040 Madrid (Spain); Lalkovski, S. [Faculty of Physics, University of Sofia, St. Kliment Ohridski, BG-1164 Sofia (Bulgaria)

    2015-09-21

    We have characterized in depth the time response of three detectors equipped with cylindrical LaBr{sub 3}(Ce) crystals with dimensions of 1-in. in height and 1-in. in diameter, and having nominal Ce doping concentration of 5%, 8% and 10%. Measurements were performed at {sup 60}Co and {sup 22}Na γ-ray energies against a fast BaF{sub 2} reference detector. The time resolution was optimized by the choice of the photomultiplier bias voltage and the fine tuning of the parameters of the constant fraction discriminator, namely the zero-crossing and the external delay. We report here on the optimal time resolution of the three crystals. It is observed that timing properties are influenced by the amount of Ce doping and the crystal homogeneity. For the crystal with 8% of Ce doping the use of the ORTEC 935 CFD at very shorts delays in addition to the Hamamatsu R9779 PMT has made it possible to improve the LaBr{sub 3}(Ce) time resolution from the best literature value at {sup 60}Co photon energies to below 100 ps.

  17. Luminescent properties of Ce3+-doped transparent oxyfluoride glass ceramics containing BaGdF5 nanocrystals

    Institute of Scientific and Technical Information of China (English)

    王倩; 欧阳绍业; 张为欢; 杨斌; 张约品; 夏海平

    2015-01-01

    The transparent oxyfluoride glass ceramics containing BaGdF5 nanocrystals were prepared with a composition of 42SiO2-12Na2O-16Al2O3-24BaF2-4Gd2O3-2CeF3 (mol.%) by thermal treatment technology. The typical DSC curve, X-ray diffraction (XRD) and transmission electron microscopy (TEM) patterns were measured. The transmission spectra and luminescent properties were in-vestigated. The decay times of the Gd3+ions at 312 nm excited with 275 nm for the Ce3+ions doped glass and glass ceramics speci-mens and the energy transfer process between Gd3+ions and Ce3+ions were also studied. The XRD analysis and the TEM images confirmed the generation of the spherical BaGdF5 nanocrystals. Compared with the PG specimen, the intensity of the luminescence spectra of the glass ceramics specimens was apparently enhanced with the heat treatment temperature increasing, and a blue shift in the excitation spectra and the emission spectra of glass ceramics specimens was obviously observed. In the fluorescence decay curves of the Gd3+ions, it could be obviously observed that the fluorescent intensity decays in the Ce3+ions doped glass and glass ceramics specimens decreased rapidly with the increase of the heat treatment temperature. In addition, the energy transfer efficiency from Gd3+ions to Ce3+ions was also calculated.

  18. Preparation of hierarchical layer-stacking Mn-Ce composite oxide for catalytic total oxidation of VOCs

    Institute of Scientific and Technical Information of China (English)

    唐文翔; 武晓峰; 刘刚; 李双德; 李东艳; 李文辉; 陈运法

    2015-01-01

    Hierarchical layer-stacking Mn-Ce composite oxide with mesoporous structure was firstly prepared by a simple precipita-tion/decomposition procedure with oxalate precursor and the complete catalytic oxidation of VOCs (benzene, toluene and ethyl ace-tate) were examined. The Mn-Ce oxalate precursor was obtained from metal salt and oxalic acid without any additives. The resulting materials were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), en-ergy dispersive X-ray spectroscopy (EDX), hydrogen temperature programmed reduction (H2-TPR) and X-ray photoelectron spec-troscopy (XPS). Compared with Mn-Ce composite oxide synthesized through a traditional method (Na2CO3 route), the hierarchical layer-stacking Mn-Ce composite oxide exhibited higher catalytic activity in the complete oxidation of volatile organic compounds (VOCs). By means of testing, the data revealed that the hierarchical layer-stacking Mn-Ce composite oxide possessed superior physiochemical properties such as good low-temperature reducibility, high manganese oxidation state and rich adsorbed surface oxy-gen species which resulted in the enhancement of catalytic abilities.

  19. ceúčelové objekty v Podlesí u Příbrami

    OpenAIRE

    Dragounová, Iva

    2015-01-01

    Předmětem práce je návrh dřevěného víceúčelového komplexu v obci Podlesí u Příbrami. Komplex se stává z administrativní budovy a víceúčelové haly, které jsou vzájemně spojeny koridorem. Administrativní budova o třech nadzemních podlažích je navržena jako dřevěný skelet. Víceúčelová hala je řešena jako dřevěná rámová soustava. Koridor, který spojuje administrativní budovu s halou, je navržen ve výšce 1,3 m nad zemí. Koridor je řešen jako dřevěná konstrukce. Klimatická zatížení jsou uvažována p...

  20. Electronic structure of LaTe and CeTe

    Energy Technology Data Exchange (ETDEWEB)

    Chainani, A., E-mail: chainania@gmail.com [RIKEN SPring-8 Centre, 1-1-1 Kouto, Hyogo 679-5148 (Japan); Department of Physics, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578 (Japan); Oura, M. [RIKEN SPring-8 Centre, 1-1-1 Kouto, Hyogo 679-5148 (Japan); Matsunami, M. [UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585 (Japan); Ochiai, A.; Takahashi, T. [Department of Physics, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578 (Japan); Tanaka, Y. [RIKEN SPring-8 Centre, 1-1-1 Kouto, Hyogo 679-5148 (Japan); Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Hyogo 678-1297 (Japan); Tamasaku, K.; Kohmura, Y.; Ishikawa, T. [RIKEN SPring-8 Centre, 1-1-1 Kouto, Hyogo 679-5148 (Japan)

    2016-04-15

    Highlights: • Hard X-ray and soft X-ray photoelectron spectroscopy of LaTe and CeTe. • Evidence for Kondo screening in antiferromagnetic(T{sub N} = 2.2 K) compound CeTe. • Suppressed Kondo resonance in CeTe compared to typical Kondo materials. - Abstract: We report a comparative study of the electronic structure of the compounds LaTe and CeTe, both of which crystallize in the rock salt structure. LaTe is a paramagnetic metal while CeTe is known to exhibit anomalous Kondo-like transport behaviour and undergoes a transition to a complex magnetically ordered state at low temperature (T{sub N} = 2.2 K). We carry out hard X-ray photoelectron spectroscopy (HAXPES) of the core-levels and valence band of LaTe and CeTe at T = 20 K, in order to characterize their intrinsic electronic structure, and to address the role of Kondo effect on the electronic structure of CeTe. The bulk sensitive core level HAXPES spectra show evidence of screened features in the La 3d and Ce 3d states mixed with plasmon features. From a careful analysis of the Te, La and Ce derived core levels, we separate out the respective origins of the satellites and show that CeTe indeed exhibits definitive but weak f{sup 0} and f{sup 2} satellites due to Kondo screening, in addition to the main f{sup 1} peak. The comparison of the valence band spectra of CeTe obtained using HAXPES and soft X-ray PES clearly identifies the Ce 4f derived features. Resonant photoelectron spectrosocopy across the Ce 3d − 4f threshold confirms the Ce 4f{sup 1} final state at the Fermi level, corresponding to the tail of the Kondo resonance feature which occurs above the Fermi level, while the Ce 4f{sup 0} final state feature is observed at a binding energy of 2.4 eV. The 4f{sup 0} and 4f{sup 1} final states show giant resonances compared to the off-resonant spectra. However, in contrast to typical Kondo systems, the tail of the Ce 4f{sup 1} Kondo resonance at the Fermi level is relatively suppressed compared to the Ce 4f

  1.  Standardy rachunkowości stanowiące podstawę sporządzania sprawozdań finansowych przez jednostki wydobywające gaz łupkowy w Polsce i w Stanach Zjednoczonych

    Directory of Open Access Journals (Sweden)

    Anna Galimska

    2015-12-01

    Full Text Available Celem artykułu jest analiza oraz porównanie standardów rachunkowości wykorzystywanych przez przedsiębiorstwa poszukujące i wydobywające gaz łupkowy w Stanach Zjednoczonych i w Polsce. Autorka dokonała zestawienia regulacji służących do sporządzania i prezentacji sprawozdań finansowych, na których opierają się jednostki eksploatujące węglowodory niekonwencjonalne. Wciąż postępujący rozwój rynków kapitałowych znajduje swoje odzwierciedlenie w intensyfikacji oczekiwań interesariuszy względem atrybutów, którymi winny charakteryzować się sprawozdania finansowe. Rozważania zawarte w artykule ukazują wysoki poziom specjalizacji amerykańskich standardów rachunkowości, na których bazują podmioty wydobywające gaz łupkowy w Stanach Zjednoczonych. Natomiast standardy międzynarodowe poruszają jedynie kwestię początkowego stadium procesu wydobycia alternatywnych węglowodorów, co rzutuje na spójność przygotowywanych na ich podstawie sprawozdań finansowych. Ponadto istotna jest kwestia rozbieżności merytorycznych czy też interpretacyjnych analizowanych standardów zarówno w zakresie identyfikacji kosztów oraz ich klasyfikacji, jak i określania wysokości odpisów z tytułu utraty wartości.

  2. Comment on "138La-138Ce-136Ce nuclear cosmochronometer of the supernova neutrino process"

    CERN Document Server

    Von Neumann-Cosel, P; Byelikov, A

    2009-01-01

    The nuclear chosmochronometer suggested by Hayakawa et al. [Phys. Rev.C 77, 065802 (2008)] based on the 138La-138Ce-136Ce abundance ratio in presolar grains would be affected by the existence of a hitherto unknown low-energy 1+ state in 138La. Results of a recent high-resolution study of the 138Ba(3He,t) reaction under kinematics selectively populating 1+ states in 138La through Gamow-Teller transitions provides strong evidence against the existence of such a hypothetical state.

  3. Search for double beta decay of $^{136}$Ce and $^{138}$Ce with HPGe gamma detector

    CERN Document Server

    Belli, P; Boiko, R S; Cappella, F; Cerulli, R; Danevich, F A; Incicchitti, A; Kropivyansky, B N; Laubenstein, M; Poda, D V; Polischuk, O G; Tretyak, V I

    2014-01-01

    Search for double $\\beta$ decay of $^{136}$Ce and $^{138}$Ce was realized with 732 g of deeply purified cerium oxide sample measured over 1900 h with the help of an ultra-low background HPGe $\\gamma$ detector with a volume of 465 cm$^3$ at the STELLA facility of the Gran Sasso National Laboratories of the INFN (Italy). New improved half-life limits on double beta processes in the cerium isotopes were set at the level of $\\lim T_{1/2}\\sim 10^{17}-10^{18}$~yr; many of them are even two orders of magnitude larger than the best previous results.

  4. Study of Ce-modified antibacterial 316L stainless steel

    Directory of Open Access Journals (Sweden)

    Yuan Junping

    2012-11-01

    Full Text Available 316L stainless steel is widely used for fashion jewelry, but it can carry a large number of bacteria and bring the risk of infection since the steel has no antimicrobial performance. In this paper, the effects of Ce on the antibacterial property, corrosion resistance and processability of 316L were studied by microscopic observation, thin-film adhering quantitative bacteriostasis, and electrochemical and mechanical tests. The results show that a trace of Ce can distribute uniformly in the matrix of 316L and slightly improve its corrosion resistance in artificial sweat. With an increase in Ce content, the Ce is prone to form clustering, which degrades the corrosion resistance and the processability. The Ce-containing 316L exhibits Hormesis effect against S. aureus. A small Ce addition stimulates the growth of S. aureus. As the Ce content increases, the modified 316L exhibits an improved antibacterial efficacy. The more Ce is added, the better antibacterial capability is achieved. Overall, if the 316L is modified with Ce alone, it is difficult to obtain the optimal combination of corrosion resistance, antibacterial performance and processability. In spite of that, 0.15 wt.%-0.20 wt.% Ce around is inferred to be the best trade-off.

  5. Preceptoria de território, novas práticas e saberes na estratégia de educação permanente em saúde da família: o estudo do caso de Sobral, CE Preceptorship of territory, new practices and knowledge in the strategy of continuing education in family health strategy: the case study of Sobral, Ceara, Brazil

    Directory of Open Access Journals (Sweden)

    Rosani Pagani

    2012-05-01

    Full Text Available O presente trabalho pretende apresentar um novo ator no Sistema Único de Saúde - o preceptor de território - bem como discutir sua atuação. Com a implantação da Estratégia Saúde da Família, bastante se tem discutido sobre o desafio de formar profissionais para atuarem neste modelo através de educação permanente em saúde. Nesse processo, o município de Sobral, CE, criou em 1999 a residência multiprofissional e a preceptoria de território; em 2001, a Escola de Formação em Saúde da Família Visconde de Sabóia. Este estudo teve como objetivos analisar a implantação e a atuação da preceptoria de território, descrevendo o processo de trabalho dos preceptores e identificando suas competências; além disso, descreveu-se o processo de educação permanente desenvolvido na Estratégia de Saúde da Família em Sobral. Utilizou-se uma abordagem qualitativa do tipo estudo de caso, com os seguintes instrumentos: entrevistas, questionários e grupo focal. Para a organização os dados foram analisados através da técnica do Discurso do Sujeito Coletivo (DSC. Entre os achados do estudo, identifica-se o preceptor de território como um profissional que atua diretamente com os residentes nos territórios das equipes da estratégia de saúde da família, destacando-se por suas amplas competências. Entre estas, podem ser mencionados conhecimentos conceituais nos campos da saúde coletiva e das relações humanas, bem como conhecimento e desenvoltura na utilização de métodos de ensino (problematização, educação permanente em saúde e educação popular. Deve também ser capaz de desenvolver relações harmônicas e de participação. O debate vem auxiliando o preceptor de território de Sobral a estabelecer seu papel e consolidar sua função de educador na construção do SUS.This paper aims to present a new actor in the Health's Unique System of Brazil (SUS, the preceptor of territory, and discuss his performance. The

  6. Impact of water composition on association of Ag and CeO₂ nanoparticles with aquatic macrophyte Elodea canadensis.

    Science.gov (United States)

    Van Koetsem, Frederik; Xiao, Yi; Luo, Zhuanxi; Du Laing, Gijs

    2016-03-01

    In this study, the potential association of (citrate-stabilized) Ag (14.1 ± 1.0 nm) and CeO2 (6.7 ± 1.2 nm) engineered nanoparticles (ENPs), or their ionic counterparts, with the submerged aquatic plant Elodea canadensis, was examined and, in particular, parameters affecting the distribution of the nanoparticles (or metal ions) between plant biomass and the water phase were assessed using five distinct aqueous matrices (i.e. tap water, 10 % Hoagland's solution and three natural surface water samples). Individual plants were exposed to varying concentrations of Ag and CeO2 ENPs or Ag(+) and Ce(3+) ions during 72-h-lasting batch experiments. A dose-dependent increase of silver or cerium in plant biomass was observed for both the nanoparticles and the ions, whereby exposure to the latter systematically resulted in significantly higher biomass concentrations. Furthermore, the apparent plant uptake of CeO2 ENPs appeared to be higher than that for Ag ENPs when comparing similar exposure concentrations. These findings suggest that association with E. canadensis might be affected by particle characteristics such as size, composition, surface charge or surface coating. Moreover, the stability of the ENPs or ions in suspension/solution may be another important aspect affecting plant exposure and uptake. The association of the nanoparticles or ions with E. canadensis was affected by the physicochemical characteristics of the water sample. The silver biomass concentration was found to correlate significantly with the electrical conductivity (EC), dry residue (DR) and Cl(-), K, Na and Mg content in the case of Ag ENPs or with the EC, inorganic carbon (IC) and Cl(-), NO3 (-), Na and Mg content in the case of Ag(+) ions, whereas significant relationships between the cerium biomass concentration and the EC, DR, IC and Ca content or the pH, EC, DR, IC and Cl(-), Ca and Mg content were obtained for CeO2 ENPs or Ce(3+) ions, respectively. Results also indicated that the Ag

  7. Associação entre hiperglicemia e morbimortalidade em pacientes críticos na Unidade de Terapia Intensiva de um hospital terciário de Fortaleza – CE doi:10.12662/2317-3076jhbs.v3i3.186.p132-136.2015

    Directory of Open Access Journals (Sweden)

    Amanda Araújo Braga

    2015-09-01

    Full Text Available Introdução: A hiperglicemia é frequentemente associada ao aumento da morbimortalidade em Unidades de Terapia Intensiva. Objetivo: o objetivo deste estudo foi avaliar o impacto do controle glicêmico em pacientes criticamente enfermos. Métodos: Estudo transversal, em que foram revisados os prontuários de pacientes internados na UTI de um hospital público terciário. Foram analisados dois subgrupos de pacientes, um com 100 indivíduos que foram a óbito e outro com 100 indivíduos que receberam alta. Resultados: A média dos níveis glicêmicos no 1º dia dos pacientes que evoluíram para óbito foi 145,6 ±61,5 mg/dL, enquanto que os da alta foi 133,2±38,9 mg/dL (p=0,046. No 7o dia de internação na UTI, a média nos pacientes que evoluíram a óbito foi de 160,6±81,4 mg/dL e os da alta foi 125,6±35,7 mg/dL (p=0,017.  Episódios de hiperglicemia ocorreram em 68,2% dos pacientes que foram a óbito e em 31,8% dos pacientes que receberam alta hospitalar (p<0,001. A insulinoterapia IV e SC no subgrupo de pacientes que evoluíram a óbito foi significativamente maior (p<0,001. Foi observado que a presença de hiperglicemia por três ou mais dias foi mais comum no subgrupo de pacientes que foram a óbito. Conclusão: Os episódios de hiperglicemia e consequentemente o uso de insulina exógena foram mais frequentes no subgrupo de pacientes que evoluíram para o óbito.

  8. Facile hydrothermal synthesis of CeO2 nanopebbles

    Indian Academy of Sciences (India)

    N Sabari Arul; D Mangalaraj; Jeong In Han

    2015-09-01

    Cerium oxide (CeO2) nanopebbles have been synthesized using a facile hydrothermal method. X-ray diffraction pattern (XRD) and transmission electron microscopy analyses confirm the presence of CeO2 nanopebbles. XRD shows the formation of cubic fluorite CeO2 and the average particle size estimated from the Scherrer formula was found to be 6.69 nm. X-ray absorption spectrum of CeO2 nanopebbles exhibits two main sharp white lines at 880 and 898 eV due to the spin orbital splitting of 4 and 5. Optical absorption for the synthesized CeO2 nanopebbles exhibited a blue shift (g = 3.35 eV) with respect to the bulk CeO2 (g = 3.19 eV), indicating the existence of quantum confinement effects.

  9. A thermodynamic assessment of Ce-Al system

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The optimized descriptions of the phase diagram and thermodynamic properties for Ce-Al system have been obtained from experimental thermodynamic and phase diagram data by means of the computer program THERMO-CALC based on the least squares method, using models for the Gibbs energy of individual phases. The system contains five intermetallic compounds. The calculated standard enthalpies of Ce3Al, CeAl, CeAl2, CeAl3 and Ce3Al11 are -26.7, -48.9, -48.4, -44.0 and -41.7 kJ/mol, respectively. A consistent set of thermodynamic parameters was derived. The optimized and experimental data are in good agreement.

  10. Dissolution of Ce from Cd Solution Containing U/Ce Elements by Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Si Hyung; Kim, Gha-Young; Lee, Seung-jai; Kim, Taek-Jin; Paek, Seungwoo; Ahn, Do-Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The U-TRU metal alloy can be supplied by the Pyroprocessing, specifically UTRU recovery process using liquid cadmium cathode (LCC). In a certain case, a lot of rare earth (RE) element could be recovered on the LCC with the TRU element during the Pyroprocessing when the concentration of RE ions is higher than that of the TRU ions in the salt. In this case, most of the RE element needs to be removed from the Cd solution containing U/TRU/RE elements. RAR(Residual Actinides Recovery) technique used the mixed electrolytic-chemical process. In this study, only electrolysis technique was utilized to remove Ce element from Cd solution containing U/Ce elements. U-TRU alloy having less impurity is necessary for the fabrication of SFR fuel and these U-TRU elements can be prepared by Pyroprocessing. Electrolytic method was used to reduce the amount of Ce elements from the Cd solution containing U/Ce elements. It is judged from this study that electrolytic dissolution can be one of the methods to reduce RE elements from the Cd solution containing U-TRU-RE elements.

  11. Windows CE自定制Shell%Customizing Windows CE Shell

    Institute of Scientific and Technical Information of China (English)

    覃朗; 雷跃明

    2010-01-01

    Shell是用户访问操作系统的接口.Shell开发在Windows CE操作系统开发中占据一定的重要性.对Windows CE Shell进行了概述,并通过建立Shell模型,讲述如何自定制Windows CE Shell和定制Shell必须注意的问题,对Windows CE Shell的定制进行深入研究.

  12. Sorption of La(III) and Ce(III) by oxidized carbon nanotubes

    Science.gov (United States)

    Lyu, Sh. T.; Rakov, E. G.

    2016-10-01

    The ion-exchange sorption of La(III) and Ce(III) from nitrate solutions using oxidized carbon nanotubes with a solubility of 4.2 g/L is studied at metal concentration C = 5-160 mg/L, pH 2.5-6.0, ratio S: L = 0.002-0.06, and room temperature. At C = 35 mg/L, the equilibrium capacity is shown to grow dramatically with pH rising from 3.0 to 4.0-4.5 and reaching 840 mg/g in La and 950 mg/g in Ce when S: L 4.0-4.5. The introduction of ionic salts is found to reduce the capacity (at pH > 4 and concentrations of 0.01 M and 0.1 M NaCl, the Ce capacity is reduced to ~500 and ~200 mg/g). It is concluded that the sorption equilibrium is better described by the Langmuir equation, while the process kinetics, by pseudo-first and pseudo-second order equations.

  13. Digital silicon photomultiplier readout of a new fast and bright scintillation crystal (Ce:GFAG)

    Science.gov (United States)

    Lee, Yong-Seok; Leem, Hyun-Tae; Yamamoto, Seiichi; Choi, Yong; Kamada, Kei; Yoshikawa, Akira; Park, Sang-Geon; Yeom, Jung-Yeol

    2016-10-01

    A new Gadolinium Fine Aluminum Gallate (Ce:GFAG) scintillation crystal with both high energy resolution and fast timing properties has successfully been grown. Compared to Gd3Al2Ga3O12 (Ce:GAGG), this new inorganic scintillation crystal has a high luminosity similar to and a faster decay time. In this paper, we report on the timing and energy performance results of the new GFAG scintillation crystal read out with digital silicon photomultipliers (dSiPM) for positron emission tomography (PET) application. The best coincidence resolving time (FWHM) of polished 3×3×5 mm3 crystals was 223±6 ps for GFAG crystals compared to 396±28 ps for GAGG crystals and 131±3 ps for LYSO crystals respectively. An energy resolution (511 keV peak of Na-22) of 10.9±0.2% was attained with GFAG coupled to dSiPM after correcting for saturation effect, compared to 9.5±0.3% for Ce:GAGG crystals and 11.9±0.4% for LYSO crystals respectively. It is expected that this new scintillator may be competitive in terms of overall properties such as energy resolution, timing resolution and growing (raw material) cost, compared to existing scintillators for positron emission tomography (PET).

  14. Absorption-edge transmission technique using Ce- 139 for measurement of stable iodine concentration.

    Science.gov (United States)

    Sorenson, J A

    1979-12-01

    We have investigated a technique for measuring stable iodine concentrations by absorption-edge transmission measurements using a Ce 139 radiation source. The lanthanum daughter emits characteristic x-rays whose energies just bracket the absorption edge of iodine at 33.2 keV. Relative transmission of these x-rays is sensitive to iodine concentration in the sample, but is relatively insensitive to other elements. By applying energy-selective beam filtration, it is possible to determine the relative transmission of these closely spaced x-ray energies with NaI(Tl) detectors. Optimizations of sample thickness, detector thickness, and Ce-139 source activity are discussed. Using sample volumes of about 10 ml, one can determine iodine concentration to an uncertainty (standard deviation) of +/- 5 microgram/ml with a 5-mCi source in a measurement time of 400 sec. Potential clinical applications of the in vitro technique are discussed, along with comparative aspects of the Ce-139 technique and other absorption and fluorescence techniques for measuring stable iodine.

  15. Equilibrium and kinetic modeling of adsorptive sulfur removal from gasoline by synthesized Ce-Y zeolite

    Science.gov (United States)

    Montazerolghaem, Maryam; Rahimi, Amir; Seyedeyn-Azad, Fakhry

    2010-11-01

    In this research, the adsorption of a model sulfur compound, thiophene, from a simulated gasoline onto Ce-Y zeolite in pellet and powder forms was investigated. For this purpose, zeolite Na-Y was synthesized, and Ce-Y zeolite was prepared via solid-state ion-exchanged (SSIE) method. Adsorptive desulfurization of model gasoline was conducted in a batch reactor at ambient conditions to evaluate the equilibrium and kinetics of thiophene adsorption onto Ce-Y zeolite. The equilibrium data were fitted to Langmuire and Toth models. Pseudo-n-order and modified n-order models, LDF-base model, and intra-particle diffusion model were evaluated to fit the kinetic of the adsorption process and to determine the mechanism of it. The corresponding parameters and/or correlation coefficients of each model were reported. The LDF-base model was used also to fit the mass transfer coefficient for both powder and pellet forms of the adsorbent. The best fit estimates for the mass transfer coefficient were obtained 4 × 10-11 m/s and k = 3.1 × 10-12[exp( - t/τ) + 1/(t + 10-4)], for powder and pellet form adsorbents, respectively.

  16. Digital silicon photomultiplier readout of a new fast and bright scintillation crystal (Ce:GFAG)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong-Seok [Department of Bio-convergence Engineering, Korea University, Seoul (Korea, Republic of); Leem, Hyun-Tae [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Yamamoto, Seiichi [Department of Medical Technology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Choi, Yong, E-mail: ychoi@sogang.ac.kr [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Kamada, Kei [New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai (Japan); C& A corporation, Sendai (Japan); Yoshikawa, Akira [New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai (Japan); C& A corporation, Sendai (Japan); Institute for Material Research, Tohoku University, Sendai (Japan); Park, Sang-Geon [Department of Electrical & Electronics, Silla University, Pusan (Korea, Republic of); Yeom, Jung-Yeol, E-mail: jungyeol@korea.ac.kr [Department of Bio-convergence Engineering, Korea University, Seoul (Korea, Republic of); School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of)

    2016-10-01

    A new Gadolinium Fine Aluminum Gallate (Ce:GFAG) scintillation crystal with both high energy resolution and fast timing properties has successfully been grown. Compared to Gd{sub 3}Al{sub 2}Ga{sub 3}O{sub 12} (Ce:GAGG), this new inorganic scintillation crystal has a high luminosity similar to and a faster decay time. In this paper, we report on the timing and energy performance results of the new GFAG scintillation crystal read out with digital silicon photomultipliers (dSiPM) for positron emission tomography (PET) application. The best coincidence resolving time (FWHM) of polished 3×3×5 mm{sup 3} crystals was 223±6 ps for GFAG crystals compared to 396±28 ps for GAGG crystals and 131±3 ps for LYSO crystals respectively. An energy resolution (511 keV peak of Na-22) of 10.9±0.2% was attained with GFAG coupled to dSiPM after correcting for saturation effect, compared to 9.5±0.3% for Ce:GAGG crystals and 11.9±0.4% for LYSO crystals respectively. It is expected that this new scintillator may be competitive in terms of overall properties such as energy resolution, timing resolution and growing (raw material) cost, compared to existing scintillators for positron emission tomography (PET).

  17. Valence Fluctuations in CeCo2 and Ti-Doped CeCo2

    Science.gov (United States)

    Öner, Yıldırhan

    2016-12-01

    We report on the magnetic measurements of polycrystalline samples of CeCo2 and CeCo(2-x)Ti x (x = 0.01, 0.02, 0.03, 0.04, and 0.05) which have been synthesized by an arc melting technique. All these compounds crystallize into the face-centered cubic (FCC) structure with the Fd bar{3} m space group. The lattice parameter decreases linearly with increasing Ti content from 7.15808(5) Å for x = 0 (CeCo2) to 7.15231(7) Å for x = 0.05. The magnetic behavior of these compounds has been investigated in the temperature range 5-400 K. The zero field-cooled (ZFC) and field-cooled magnetization (FC) curves show irreversibility below T = 400 K. This result indicates that an inhomogeneous, dynamic magnetic state exists over a wide temperature range. The magnetic susceptibility for both ZFC and FC cases initially decreases with Ti content and then increases with further Ti addition. This behavior is interpreted in terms of band magnetism in the presence of magnetic clusters. This result indicates that the magnetic inhomogeneity of these alloys becomes dominant over a wide temperature range. The observed temperature dependence of the magnetic susceptibility leads us to suggest that these compounds are in a mixed-valence state of the magnetic Ce3+ ions and non-magnetic Ce4+ ions. This fact allows us to successfully interpret the ZFC magnetic susceptibility data with the two-level ionic inter-configuration fluctuations model. We also observe that the magnetic susceptibility increases by the addition of Ti, as evidenced by the enhancement of the formation of magnetic Co clusters due to local disorder. Finally, the magnetic state below the Curie temperatures are discussed based on Griffiths-like behavior.

  18. The Effect of Alkali Carbonate on the Catalytic Properties for Methane Conversion with Ce-Zr-O%碱金属碳酸盐掺杂的Ce-Zr-O对甲烷转化催化性能的影响

    Institute of Scientific and Technical Information of China (English)

    段月娟; 魏永刚; 李孔斋; 王华; 祝星; 杜云鹏

    2012-01-01

    Pure Ce-Zr-O mixed oxide was prepared via precipitation method, and catalysts doped with alkali carbonates (M2CO3, M=Li, Na, K) were prepared by incipient wetness impregnation methods. The catalytic activity for methane was investigated by the gas-solid reaction in a fixed bed reactor, and characterized by means of XRD and H2-TPR techniques. The results show that the catalytic activity of Ce-Zr-O is promoted with varied following the doping of alkali carbonates, the anti-coking and anti-sintering properties of the catalysts are enhanced, and the surface oxygen species and the bulk oxygen species of the catalysts are improved as well.%采用共沉淀法制备了Ce-Zr-O载体,通过等体积浸渍法得到碱金属碳酸盐掺杂的M2CO3/Ce-Zr-O(M=Li,Na,K)催化剂.采用自制的小型固定床反应器考察了催化剂的甲烷转化催化活性,并利用XRD和H2-TPR对催化剂进行了表征.研究结果表明,碱金属碳酸盐的添加均不同程度地提高了Ce-Zr-O催化剂的催化活性、抗积碳性能和抗烧结性能,还改善了催化剂表面氧物种和体相氧物种的氧化还原性能.

  19. Inverted opal luminescent Ce-doped silica glasses

    Directory of Open Access Journals (Sweden)

    R. Scotti

    2006-01-01

    Full Text Available Inverted opal Ce-doped silica glasses (Ce : Si molar ratio 1 ⋅ 10−3 were prepared by a sol-gel method using opals of latex microspheres as templates. The rare earth is homogeneously dispersed in silica host matrix, as evidenced by the absence of segregated CeO2, instead present in monolithic Ce-doped SG with the same cerium content. This suggests that the nanometric dimensions of bridges and junctions of the host matrix in the inverted opal structures favor the RE distribution avoiding the possible segregation of CeO2.

  20. Evaluation of transport parameters for PVC based polyvinyl alcohol Ce(IV) phosphate composite membrane

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Mohammad Mujahid Ali, E-mail: mujahidchemistry@gmail.com [Membrane Research Laboratory, Department of Chemistry, Aligarh Muslim University, Aligarh, 202002 (India); Rafiuddin,; Inamuddin [Department of Applied Chemistry, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh-202002 (India)

    2013-05-01

    The aim of this study was to investigate the preparation of novel membrane and the characterization of their properties. A new class of polyvinyl chloride (PVC) based polyvinyl alcohol Ce(IV) phosphate composite membrane was successfully prepared by solution casting method. The structural formation was confirmed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and morphological studies. The thermal property was investigated by thermogravimetry analysis (TGA) method. The order of surface charge density for various electrolytes was found to be LiCl < NaCl < KCl. - Highlights: ► Transport properties of composite membrane are evaluated. ► TMS method is used for electrochemical characterization. ► Membrane was found to be mechanically stable. ► The order of surface charge density was found to be LiCl < NaCl < KCl.

  1. Preparation,Characterization of CuO/CeO2 and Cu/CeO2 Catalysts and Their Applications in Low-Temperature CO Oxidation

    Institute of Scientific and Technical Information of China (English)

    Zheng Xiucheng; Han Dongzhan; Wang Shuping; Zhang Shoumin; Wang Shurong; Huang Weiping; Wu Shihua

    2005-01-01

    CeO2 was synthesized via sol-gel process and used as supporter to prepare CuO/CeO2, Cu/CeO2 catalysts by impregnation method. The catalytic properties and characterization of CeO2, CuO/CeO2 and Cu/CeO2 catalysts were examined by means of a microreactor-GC system, HRTEM, XRD, TPR and XPS techniques. The results show that CuO has not catalytic activity and the activity of CeO2 is quite low for CO oxidation. However, the catalytic activity of CuO/CeO2 and Cu/CeO2 catalysts increases significantly. Furthermore, the activity of CuO/CeO2 is higher than that of Cu/CeO2 catalysts.

  2. Dependence of the Ce(iii)/Ce(iv) ratio on intracellular localization in ceria nanoparticles internalized by human cells

    KAUST Repository

    Ferraro, Daniela

    2017-01-09

    CeO2 nanoparticles (CNPs) have been investigated as promising antioxidant agents with significant activity in the therapy of diseases involving free radicals or oxidative stress. However, the exact mechanism responsible for CNP activity has not been completely elucidated. In particular, in situ evidence of modification of the oxidative state of CNPs in human cells and their evolution during cell internalization and subsequent intracellular distribution has never been presented. In this study we investigated modification of the Ce(iii)/Ce(iv) ratio following internalization in human cells by X-ray absorption near edge spectroscopy (XANES). From this analysis on cell pellets, we observed that CNPs incubated for 24 h showed a significant increase in Ce(iii). By coupling on individual cells synchrotron micro-X-ray fluorescence (μXRF) with micro-XANES (μXANES) we demonstrated that the Ce(iii)/Ce(iv) ratio is also dependent on CNP intracellular localization. The regions with the highest CNP concentrations, suggested to be endolysosomes by transmission electron microscopy, were characterized by Ce atoms in the Ce(iv) oxidation state, while a higher Ce(iii) content was observed in regions surrounding these areas. These observations suggest that the interaction of CNPs with cells involves a complex mechanism in which different cellular areas play different roles.

  3. Preparation method of Ce{sub 1-x}Zr{sub x}O{sub 2}/tourmaline nanocomposite with high far-infrared emissivity and its mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Bin; Li, Wenlong [Chinese Academy of Sciences, State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics, Xi' an (China); University of Chinese Academy of Sciences, Beijing (China); Yang, Liqing; Wang, Haojing; Zhang, Hong [Chinese Academy of Sciences, State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics, Xi' an (China)

    2016-02-15

    Far-infrared functional nanocomposites were prepared by the coprecipitation method using natural tourmaline (XY{sub 3}Z{sub 6}Si{sub 6}O{sub 18}(BO{sub 3}){sub 3}V{sub 3}W, where X is Na{sup +}, Ca{sup 2+}, K{sup +}, or vacancy; Y is Mg{sup 2+}, Fe{sup 2+}, Mn{sup 2+}, Al{sup 3+}, Fe{sup 3+}, Mn{sup 3+}, Cr{sup 3+}, Li{sup +}, or Ti{sup 4+}; Z is Al{sup 3+}, Mg{sup 2+}, Cr{sup 3+}, or V{sup 3+}; V is O{sup 2-}, OH{sup -}; and W is O{sup 2-}, OH{sup -}, or F{sup -}) powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that Ce-Zr can further enhance the far-infrared emission properties of tourmaline than Ce alone. Through characterization by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), the mechanism by which Ce(-Zr) acts on the far-infrared emission property of tourmaline was systematically studied. The XPS spectra show that the Fe{sup 3+} ratio inside tourmaline powders after heat treatment can be raised by doping Ce and further raised after adding Zr. Moreover, it is showed that Ce{sup 3+} is dominant inside the samples, but its dominance is replaced by Ce{sup 4+} outside. In addition, XRD results indicate the formation of CeO{sub 2} and Ce{sub 1-x}Zr{sub x}O{sub 2} crystallites during the heat treatment, and further, TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce-Zr-doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of Fe{sup 2+} (0.074 nm in radius) to Fe{sup 3+} (0.064 nm in radius) inside the tourmaline caused by Zr enhancing the redox shift between Ce{sup 4+} and Ce{sup 3+} via improving the

  4. Lanthanide 4f-level location in lanthanide doped and cerium-lanthanide codoped NaLaF4 by photo- and thermoluminescence

    NARCIS (Netherlands)

    Krumpel, A.H.; Van der Kolk, E.; Zeelenberg, D.; Bos, A.J.J.; Krämer, K.W.; Dorenbos, P.

    2008-01-01

    Photo- and thermoluminescence (TL) spectra of NaLaF4:Ln3+ (Ln = Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm) and NaLaF4:Ce3+, Ln3+ (Ln = Nd,Sm,Ho,Er,Tm) are presented and used together with the empirical Dorenbos model in order to establish the 4f energy level positions of all tri- and divalent lanthanide ions

  5. Scintillation in LiBaF3(Ce) crystals

    NARCIS (Netherlands)

    Gektin, A; Shiran, N; Voloshinovski, A; Voronova, [No Value; Zimmerer, G

    1998-01-01

    Core-valence, self-trapped exciton and Ce3+-luminescences in pure and doped LiBaF3 crystals were determined on the basis of analysis of the time resolved emission and excitation spectra. It is shown that excitation of Ce-luminescence is caused both by carriers capture at or near activator ions and b

  6. Neutron detection using conversion layers and YAP:Ce and YAG:Ce crystals

    Directory of Open Access Journals (Sweden)

    Fiserova Lucie

    2015-01-01

    Full Text Available The work deals with the detection of thermal neutrons using a conversion layer of LiF on YAP:Ce and YAG:Ce scintillation crystals of various sizes. Enriched LiF (95 at. % 6Li in the form of a mixture with 5 % polyvinyl alcohol was deposited on the crystal face by spraying it in a thin layer. The 252Cf isotope with paraffin moderation and lead shielding was used as a neutron source. The detection is based on the nuclear reaction of 6Li with the neutron. The conversion leads to emitting an alpha particle and triton according to the scheme 6Li (n, a3H + + 4.5 MeV which are detected by the scintillation crystal. Due to gamma ray interaction, the optimum thickness of the crystal was estimated to 70 µm.

  7. Epitaxial Ce and the magnetism of single-crystal Ce/Nd superlattices

    OpenAIRE

    Clegg, P. S.; Goff, J.P.; McIntyre, G. J.; Ward, R.C.C.; Wells, M. R .

    2003-01-01

    The chemical structure of epitaxial gamma cerium and the chemical and magnetic structures of cerium/neodymium superlattices have been studied using x-ray and neutron diffraction techniques. The samples were grown using molecular-beam epitaxy, optimized to yield the desired Ce allotropes. The x-ray measurements show that, in the superlattices, both constituents adopt the dhcp structure and that the stacking sequence remains intact down to Tsimilar to2 K; these are the first measurements of mag...

  8. CE APPROVAL IN ELECTRICAL HOUSEHOLD APPLIANCES AND A CASE STUDY

    Directory of Open Access Journals (Sweden)

    Nazmi EKREN

    2009-01-01

    Full Text Available Due to the reason for rapidly developing technology, increasing competition medium, and awareness of the consumers, nowadays, the exigency of production with good quality has gained more and more significance. Certification of the quality and safety of the products to the consumers is compulsory in terms of producers. There are some documents to certify safety of the products. One of them is CE certificate. In this paper, basic information about CE mark is given and CE standards and tests required for electrical household appliances are mentioned. As an application, one of an electrical household appliance, toaster grill is treated and examined. To obtain CE certificate for toaster grill, required tests are made according to EN60335-2-9 and CE certificate is obtained.

  9. First-Principles Phase Diagram for Ce-Th System

    Energy Technology Data Exchange (ETDEWEB)

    Landa, A; Soderlind, P; Ruban, A; Vitos, L; Pourovskii, L

    2004-05-11

    Ab initio total energy calculations based on the exact muffin-tin orbitals (EMTO) theory are used to determine the high pressure and low temperature phase diagram of Ce and Th metals as well as the Ce{sub 43}Th{sub 57} disordered alloy. The compositional disorder for the alloy is treated in the framework of the coherent potential approximation (CPA). Equation of state for Ce, Th and Ce{sub 43}Th{sub 57} has been calculated up to 1 Mbar in good comparison with experimental data: upon compression the Ce-Th system undergoes crystallographic phase transformation from an fcc to a bct structure and the transition pressure increases with Th content in the alloy.

  10. Seamless Ligation Cloning Extract (SLiCE) cloning method.

    Science.gov (United States)

    Zhang, Yongwei; Werling, Uwe; Edelmann, Winfried

    2014-01-01

    SLiCE (Seamless Ligation Cloning Extract) is a novel cloning method that utilizes easy to generate bacterial cell extracts to assemble multiple DNA fragments into recombinant DNA molecules in a single in vitro recombination reaction. SLiCE overcomes the sequence limitations of traditional cloning methods, facilitates seamless cloning by recombining short end homologies (15-52 bp) with or without flanking heterologous sequences and provides an effective strategy for directional subcloning of DNA fragments from bacterial artificial chromosomes or other sources. SLiCE is highly cost-effective and demonstrates the versatility as a number of standard laboratory bacterial strains can serve as sources for SLiCE extract. We established a DH10B-derived E. coli strain expressing an optimized λ prophage Red recombination system, termed PPY, which facilitates SLiCE with very high efficiencies.

  11. Ce3+-ion-induced visible-light photocatalytic degradation and electrochemical activity of ZnO/CeO2 nanocomposite

    OpenAIRE

    2016-01-01

    In this study, pure ZnO, CeO2 and ZnO/CeO2 nanocomposites were synthesized using a thermal decomposition method and subsequently characterized using different standard techniques. High-resolution X-ray photoelectron spectroscopy measurements confirmed the oxidation states and presence of Zn2+, Ce4+, Ce3+ and different bonded oxygen species in the nanocomposites. The prepared pure ZnO and CeO2 as well as the ZnO/CeO2 nanocomposites with various proportions of ZnO and CeO2 were tested for photo...

  12. Ce4+/Ce3+-V2+/V3+氧化还原流动电池的可行性研究(Ⅱ)--旋转圆盘(RDE)与旋转环盘(RRDE)法对Ce4+/Ce3+氧化还原体系的研究%Studies on Feasibility of Ce4+/Ce3+ - V2+/V3+ Redox Flow Cell ( Ⅱ ) --Investigation of Ce4 +/Ce3 + Redox System by RDE and RRDE

    Institute of Scientific and Technical Information of China (English)

    夏熙; 刘洋; 刘洪涛

    2001-01-01

    用RDE与REDE法研究了Ce4+/Ce3+-V2+/V3+氧化还原流动电池中Ce4+/Ce3+体系的电化学动力学参数,以说明组成该新型氧化还原流动电池的可能性.用RDE法得出在铂电极表面与玻碳电极上均会生成一层氧化膜,对Ce3+的氧化反应产生阻碍作用.但在铂上的氧化膜对Ce4+的还原反应却有催化作用.用Rrde法得出Ce3+在玻碳电极上的氧化与析氧之间存在着竞争,为得到较高的Ce3+氧化效率,应控制氧化电流在2~8 mA@cm-2之间.

  13. The mixed-valence state of Ce in the hexagonal CeNi sub 4 B compound

    CERN Document Server

    Tolinski, T; Pugaczowa-Michalska, M; Chelkowska, G

    2003-01-01

    Measurements of the magnetic susceptibility chi, x-ray photoemission spectra (XPS), electrical resistivity rho and electronic structure calculations for CeNi sub 4 B are reported. In the paramagnetic region, CeNi sub 4 B follows the Curie-Weiss law with mu sub e sub f sub f = 0.52 mu sub B /fu and theta -10.7 K. The effective magnetic moment is lower than the free Ce sup 3 sup + -ion value. The Ce(3d) XPS spectra have confirmed the mixed-valence state of Ce ions in CeNi sub 4 B. The f occupancy, n sub f , and the coupling DELTA between the f level and the conduction states were derived to be about 0.83 and 85 meV, respectively. Both susceptibility data and XPS spectra show that Ce ions in CeNi sub 4 B are in the intermediate-valence state. At low temperatures (below 12 K), the magnetic contribution to the electrical resistivity reveals a logarithmic slope characteristic of Kondo-like systems.

  14. Effects of doping CeO{sub 2}/TiO{sub 2} on structure and properties of silicate glass

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhenlin, E-mail: wzl@cqut.edu.cn [Science and Technology on Thermostructural Composites Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); College of Materials Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China); Cheng, Laifei [Science and Technology on Thermostructural Composites Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China)

    2014-06-01

    Highlights: • Doping CeO{sub 2} results in depolymerization and narrowed Q{sup n} distribution. • Co-doping CeO{sub 2} and TiO{sub 2} favors enhanced network and broader Q{sup n} distribution. • Cerium acts as modifier and titanium as intermediate in glass network structure. • Adding CeO{sub 2}/TiO{sub 2} results in decreased optical band gap. • Doping-induced structural modifications affect mechanical properties. - Abstract: In order to elucidate the effects of doping CeO{sub 2}/TiO{sub 2} on the structure and physical properties of silicate glass, glasses with composition 72SiO{sub 2}–3Al{sub 2}O{sub 3}–10Na{sub 2}O–10K{sub 2}O–5CaO doped with varied ratios of CeO{sub 2}/TiO{sub 2} were synthesized by melt-quenching method and were characterized by X-ray diffraction, infrared and Raman spectrometry, UV–Visible spectrophotometry and micro-indentations. X-ray diffraction conforms the amorphous state of doped glasses. The spectroscopic analysis reveals that doping CeO{sub 2} alone results in depolymerization of glass network and narrowed distribution of Q{sup n} (Si–O tetrahedral with n bridging oxygen atoms), while doping TiO{sub 2} singly or combined with CeO{sub 2} favors the enhanced polymerization of network and regains a broader Q{sup n} distribution relative to doping CeO{sub 2} alone. It is proposed that doped cerium and titanium in glass exists in multivalent state and the former in presence of trivalent state preferentially acts as modifier inducing network depolymerization, whilst the latter in form of tetrahedral tends to interconnect network units as intermediate. Doped cerium in trivalent state contributes mainly to the red-shift of absorption edge while titanium suppresses such change of absorption band. Either adding cerium alone or co-doping with titanium will result in decreased optical band gap due to the structural modifications. The relatively loosened structure due to depolymerization induced by cerium is responsible for

  15. Trh práce, vláda a jejich vzájemná interakce

    OpenAIRE

    PAVLÍČEK, TOMÁŠ

    2008-01-01

    Práce popisuje některé souvislosti fungování pracovního a politického trhu.Snaží se najít odpověď na otázku jak vývoj mzdové diferenciace, nezaměstnanosti a působení odborů ovlivní politické prostředí a jeho zpětné působení na pracovní trh. Teoreticky vychází z teorií fungování pracovního trhu a některých závěrů z oblasti teorie veřejné volby. V praktické části práce analyzuje situaci v české Republice. Popisuje souvislost vývoje volebních preferencí s parametry trhu práce a souvislost implem...

  16. Low temperature SCR of NO with catalysts prepared by modified ACF loading Mn and Ce: effects of modification method.

    Science.gov (United States)

    Li, Ping; Lu, Pei; Zhai, Yunbo; Li, Caiting; Chen, Ting; Qing, Renpeng; Zhang, Wei

    2015-01-01

    Achievement of a higher NOx conversion ratio in selective catalytic reduction (SCR) at low temperature is challenging. In this work, pure activated carbon fibres (ACFs) were modified with different ratios of H2O (g), NaOH, CO2 and HNO3, respectively (named as modified ACF). The chemical and physical properties of modified ACFs were identified by Brunauer-Emmett-Teller, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy methods. The NOx conversion ratio of ACF was improved from 56.1% to 82.4% at 80°C after modification with 30% (mass ratio) NaOH. These modified ACFs were further loaded with the mixture of MnO2 and CeO2 in the form of metal salt solutions (named as Mn0.5Ce0.5O2/modified ACF). The NOx conversion ratio of 30% SHACF remained similar at 80°C but was increased from 60.0% to 98.5% at 360°C after loading with Mn and Ce, which showed the best performance in SCR of NOx at low temperature. It could be seen that ACF delivered higher performance in low temperature SCR after being modified with the aforementioned reactants and further loading with metals. Based on chemical and physical characterization and the performance of the catalysts, the reasons for different performances of these catalysts in low temperature SCR are discussed.

  17. The formation of intermetallic compounds during interdiffusion of Mg–Al/Mg–Ce diffusion couples

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Jiahong [College of Materials Science and Engineering, National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Jiang, Bin, E-mail: jiangbinrong@cqu.edu.cn [College of Materials Science and Engineering, National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Chongqing Academy of Science and Technology, Chongqing 401123 (China); Li, Xin [College of Materials Science and Engineering, National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Yang, Qingshan [College of Materials Science and Engineering, National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Chongqing Academy of Science and Technology, Chongqing 401123 (China); Dong, Hanwu [Chongqing Academy of Science and Technology, Chongqing 401123 (China); Xia, Xiangsheng [No. 59 Institute of China Ordnance Industry, Chongqing 400039 (China); Pan, Fusheng [College of Materials Science and Engineering, National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Chongqing Academy of Science and Technology, Chongqing 401123 (China)

    2015-01-15

    Graphical abstract: Al–Ce intermetallic compounds (IMCs) formed in Mg–Al/Mg–Ce diffusion couples. During the whole diffusion process, Al was the dominant diffusing species, and it substituted for Mg atoms of the Mg–Ce substrate. Five Al–Ce IMCs of Al{sub 4}Ce, Al{sub 11}Ce{sub 3}, Al{sub 3}Ce, Al{sub 2}Ce, and AlCe were formed via the reaction of Al and Ce. - Highlights: • Al–Ce IMCs formation in the Mg–Al/Mg–Ce diffusion couples was studied. • Formation of Al{sub 4}Ce as the first phase was rationalized using the Gibbs free energy. • The activation energy for the growth of the diffusion reaction zones was 36.6 kJ/mol. - Abstract: The formation of Al–Ce intermetallic compounds (IMCs) during interdiffusion of Mg–Al/Mg–Ce diffusion couples prepared by solid–liquid contact method was investigated at 623 K, 648 K and 673 K for 24 h, 48 h and 72 h, respectively. During the whole diffusion process, Al was the dominant diffusing species, and it substituted for Mg of the Mg–Ce substrate. Five Al–Ce IMCs of Al{sub 4}Ce, Al{sub 11}Ce{sub 3}, Al{sub 3}Ce, Al{sub 2}Ce and AlCe were formed via the reaction of Al and Ce. The formation of Al{sub 4}Ce as the first kind of IMC was rationalized on the basis of an effective Gibbs free energy model. The activation energy for the growth of the total diffusion reaction layer was 36.6 kJ/mol.

  18. Ce4+/Ce3+缓冲溶液流动注射电势检测法测定维生素C%Determining Vitamin C with Flow Injection Potentiometry in Ce4+/Ce3+ Redox Buffer

    Institute of Scientific and Technical Information of China (English)

    孔祥伟

    2003-01-01

    Ce4+/Ce3+氧化还原体系作缓冲溶液,用流动注射电势检测法测定了维生素C,将样品注射于以0.1mol/L K2SO4作支持电解质的Ce4+/Ce3+缓冲溶液试剂流, 以流通型氧化还原电势检测电极检测维生素C与Ce4+反应引起的氧化还原电对的电势变化,对3.0×10-4mol/L Ce4+/3.0×10-4mol/L Ce3+缓冲溶液,测定维生素C的线性范围为1.0×10-4~6.0×10-4mol/L,检出限为1.3×10-5mol/L,相对标准偏差为0.36%(n=4),分析频率为120次/小时.

  19. Low-temperature NMR studies of Ce-Al compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gavilano, J.L. (Laboratorium fuer Festkoerperphysik, ETH-Hoenggerberg, CH-8093 Zuerich (Switzerland)); Hunziker, J. (Laboratorium fuer Festkoerperphysik, ETH-Hoenggerberg, CH-8093 Zuerich (Switzerland)); Vonlanthen, P. (Laboratorium fuer Festkoerperphysik, ETH-Hoenggerberg, CH-8093 Zuerich (Switzerland)); Ott, H.R. (Laboratorium fuer Festkoerperphysik, ETH-Hoenggerberg, CH-8093 Zuerich (Switzerland))

    1994-04-01

    Ce-Al compounds display a variety of unconventional magnetic properties at low temperatures. This is particularly well demonstrated by the results of our low-frequency NMR studies on CeAl[sub 2], CeAl[sub 3] and Ce[sub 3]Al[sub 11]. Although CeAl[sub 2] orders antiferromagnetically below 3.4 K, the temperature dependence of the spin-lattice relaxation rate follows a Korringa law below 1 K. For CeAl[sub 3], we observe an increase of the line width below 0.9 K, but no indication of a phase transition is discernible from the temperature dependence of the spin-lattice relaxation rate. Ce[sub 3]Al[sub 11] is ferromagnetic below 6.2 K, but develops an antiferromagnetic and modulated structure below 3.3 K. A field of the order of 3 kG, however, appears to stabilize the ferromagnetic phase. Our spectroscopic data are important in view of some of the unusual thermal properties of these materials. ((orig.))

  20. On the luminescence properties of CaSO4:Ce.

    Science.gov (United States)

    Lapraz, D; Prevost, H; Iacconi, P; Guigues, C; Benabdesselam, M; Briand, D

    2002-01-01

    The luminescent properties of cerium doped calcium sulphate are studied: fluorescence and excitation spectra, optical absorption and thermoluminescence (TSL). It is known that, in rare earth doped CaSO4, only cerium induces a strong 400 degrees C TSL peak. In CaSO4:0.2%Ce samples synthesised under oxidising conditions, the recovery step of Ce3+ fluorescence is correlated with the 400 degrees C TSL peak readout, as mentioned by Nair er al. Our results indicate that an oxidation of Ce3+ ion does occur under X-irradiation (Ce3+ --> Ce4+), followed by a complete return to the trivalent state after thermal annealing at about 500 degrees C; our results confirm the hypothesis of Nair et al that Ce3+ ions are oxidised by ionising irradiation. So, a pure redox reaction seems the most probable for the 400 degrees C TSL peak of CaSO4:Ce. Moreover, the use of the 400 degrees C TSL peak for high temperature dosimetry applications is discussed.

  1. Pružné spojky na principu tekutin

    OpenAIRE

    2014-01-01

    Diplomová práce se zabývá pružnými hřídelovými spojkami, zejména novou kategorií spojek na principu tekutin. V práci je odvozen matematický model plynové pružiny a rotorové soustavy o dvou stupních volnosti. Poslední část práce se zabývá konstrukční úpravou pružné spojky s plynovými pružinami. The thesis deals with flexible shaft couplings especially with new category of flexible couplings on the principle of fluid. Mathematical model of gas spring and rotor system with two degrees of free...

  2. Fotografia na rynku aukcyjnym w Polsce

    Directory of Open Access Journals (Sweden)

    Bednarek, Anna

    2012-09-01

    Full Text Available W artykule podjęta została analiza stanu aukcyjnego rynku fotografii w Polsce w oparciu o wyniki sprzedaży z okresu od pierwszej aukcji fotografii (1996 do końca 2011 roku. Dane te pozwalają czytelnikowi na zapoznanie się z rozmiarami tego rynku (obrót, liczba sprzedanych obiektów, charakterystyką nabywanych obiektów (rekordy cenowe, średnie ceny, popularni twórcy i okresy oraz z trudnościami, które można napotkać podczas badania tego zjawiska. W podsumowaniu znalazły się przewidywania dotyczące dalszego rozwoju rynku.

  3. Properties and practical application of thin CeOx films

    Directory of Open Access Journals (Sweden)

    Maksimchuk N. V.

    2010-10-01

    Full Text Available The properties of CeOx films produced by various methods have been investigated. According to the comparative analisys “metallic mirror oxidation” method allows to produce films with significantly better characteristics than the «explosive evaporation» method. Though the latter method yields higher photosensitivity of CeOx films and structures on their base. In the process the optimal value of the substrate temperature was determined. Obtained data expand the CeOx application potential in microelectronic sensor sphere.

  4. Relativeca Dopplera efekto ^ce unuforme akcelata movo -- II

    CERN Document Server

    Paiva, F M

    2007-01-01

    Extending physics/0701092, a light source of monochromatic radiation, in rectilinear motion under constant proper acceleration, passes near an observer at rest. In the context of special relativity, we describe the observed Doppler effect. We describe also the interesting discontinuous effect when riding through occurs. An English version of this article is available. - - - - - - - - - - - \\\\ Da^urigante physics/0701092, luma fonto de unukolora radiado ^ce rekta movo ^ce konstanta propra akcelo pasas preter restanta observanto. ^Ce la special-relativeco, ni priskribas la observatan Doppleran efikon. Ni anka^u priskribas la interesan nekontinuan efikon se trapaso okazas.

  5. Degradering van Y₂SiO₅ :Ce fosforpoeie

    Directory of Open Access Journals (Sweden)

    Editorial Office

    2007-09-01

    Full Text Available Die degradering van die katodeluminessensie - (CL intensiteit van yttriumsilikaat gedoteer met serium (Y₂SiO₅:Ce is ondersoek vir moontlike toepassing in lae spanning veldemissie-vertooneenhede (FEDs.Y₂SiO₅:Ce is ’n blou luminesserende seldsameaarde-fosfor wat ondersoek word as ’n alternatief vir die tradisionele blou sinksulfied - (ZnS fosfor. X-straaldiffraksie (XRD, wat gedoen is vir karakterisering, het die ingewikkelde monokliene kristalstruktuur van Y₂SiO₅:Ce getoon.

  6. HumanViCe: Host ceRNA network in virus infected cells in human

    Directory of Open Access Journals (Sweden)

    Suman eGhosal

    2014-07-01

    Full Text Available Host-virus interaction via host cellular components has been an important field of research in recent times. RNA interference mediated by short interfering RNAs and microRNAs (miRNA, is a widespread anti-viral defence strategy. Importantly, viruses also encode their own miRNAs. In recent times miRNAs were identified as key players in host-virus interaction. Furthermore, viruses were shown to exploit the host miRNA networks to suite their own need. The complex cross-talk between host and viral miRNAs and their cellular and viral targets forms the environment for viral pathogenesis. Apart from protein-coding mRNAs, non-coding RNAs may also be targeted by host or viral miRNAs in virus infected cells, and viruses can exploit the host miRNA mediated gene regulatory network via the competing endogenous RNA effect. A recent report showed that viral U-rich non-coding RNAs called HSUR, expressed in primate virus herpesvirus saimiri (HVS infected T cells, were able to bind to three host miRNAs, causing significant alteration in cellular level for one of the miRNAs. We have predicted protein coding and non protein-coding targets for viral and human miRNAs in virus infected cells. We identified viral miRNA targets within host non-coding RNA loci from AGO interacting regions in three different virus infected cells. Gene ontology (GO and pathway enrichment analysis of the genes comprising the ceRNA networks in the virus infected cells revealed enrichment of key cellular signalling pathways related to cell fate decisions and gene transcription, like Notch and Wnt signalling pathways, as well as pathways related to viral entry, replication and virulence. We identified a vast number of non-coding transcripts playing as potential ceRNAs to the immune response associated genes; e.g. APOBEC family genes, in some virus infected cells. All these information are compiled in HumanViCe, a comprehensive database that provides the potential ceRNA networks in virus

  7. Uued IT-mõtted CeBITilt / Kai Simson

    Index Scriptorium Estoniae

    Simson, Kai

    2006-01-01

    Riigi Infosüsteemide Arenduskeskuse (RIA) pressiesindaja Rica Semjonova vahendab Eesti stendistide muljeid Hannoveris toimunud IT-messilt CeBIT, kus Eestit tutvustasid nii riigiametid kui eraettevõtted

  8. Combustion synthesis of YAG:Ce and related phosphors

    Science.gov (United States)

    Gupta, K. V. K.; Muley, A.; Yadav, P.; Joshi, C. P.; Moharil, S. V.

    2011-11-01

    YAG:Ce is an important phosphor having applications in various fields ranging from solid state lighting to scintillation detectors. YAG phosphors doped with activators are mainly synthesized by solid state reaction techniques that require high sintering temperatures (above 1500°C) to eliminate YAM and YAP phases. Though several soft chemical routes have been explored for synthesis of YAG, most of these methods are complex and phase pure materials are not obtained in one step, but prolonged annealing at temperatures around 1000°C or above become necessary. One step combustion synthesis of YAG:Ce3+ and related phosphors carried out at 500°C furnace temperature is reported here. Activation with Ce3+ could be achieved during the synthesis without taking recourse to any post-combustion thermal treatment. LEDs prepared from the combustion synthesized YAG:Ce3+, exhibited properties comparable to those produced from the commercial phosphor.

  9. Microstructure and Properties of CePO4 Ceramic

    Institute of Scientific and Technical Information of China (English)

    WANG Lijuan; DU Haiyan; OU Xiujuan

    2006-01-01

    Cerium phosphate powders were synthesized by direct solid liquid reaction of cerium dioxide and phosphate acid at the Ce∶P ratio of 1∶1. Phase-pure and fine grain size CePO4 powers could be obtained by calcining the as received powders at the temperature higher than 600 ℃. It is demonstrated that the grain size and morphology of the CePO4 powders were calcined at various temperatures. An interesting layered crystal structure and a series of microcracks that cross and occur along the extrusion stress direction on the extruded surface inside CePO4 were observed. The ductility and machinabililty of CePO4 ceramic are attributed to the layered structure. Continuous machining debris was observed on the turned surface.

  10. Převodník Ethernet na RS-232

    OpenAIRE

    Dreiseitel, Jiří

    2012-01-01

    Práce je věnována problematice konstrukce převodníku Ethernet na RS-232 za pomocí jednočipového mikrokontroléru. Cílem je seznámit čtenáře se síťovou technologií Ethernet a technologií pro sériový přenos založený na protokolu RS-232 a zároveň s technologií vestavěných systémů pro konstrukci zařízení.Součástí práce je kompletní návrh převodníku Ethernet na RS-232 včetně návrhu a implementace firmware v jazyce C za využití LwIP TCP/IP stacku. Převodník je postaven na základě vývojového kitu STM...

  11. Riziková analýza na vybrané lokalitě toku Dyje

    OpenAIRE

    2012-01-01

    Předmětem práce "Riziková analýza na vybraném toku Dyje" je zpracování rizikové analýzy na vybrané lokalitě toku Dyje. Na základě dostupných podkladů v souladu se směrnicí 2007/60/ES, vypracování map nebezpečí, map ohrožení a map rizik pro průtoky Q5, Q20 a Q100. Práce byla zpracována v programu GIS. The subject of the bachelor thesis "Risk flood analysis" is the processing risk flood analysis on the selected location Thaya flow. Flood Hazard Maps, Flood Danger Maps and Flood Risk Maps for...

  12. Cerocene Revisited: The Electronic Structure of and Interconversion Between Ce2(C8H8)3 and Ce(C8H8)2

    Energy Technology Data Exchange (ETDEWEB)

    Walter, Marc D.; Booth, Corwin H.; Lukens, Wayne W.; Andersen, Richard A.

    2009-02-02

    New synthetic procedures for the preparation of Ce(cot)2, cerocene, from [Li(thf)4][Ce(cot)2], and Ce2(cot)3 in high yield and purity are reported. Heating solid Ce(cot)2 yields Ce2(cot)3 and COT while heating Ce2(cot)3 with an excess of COT in C6D6 to 65oC over four months yields Ce(cot)2. The solid state magnetic susceptibility of these three organocerium compounds shows that Ce(cot)2 behaves as a TIP (temperature independent paramagnet) over the temperature range of 5-300 K, while that of Ce2(cot)3 shows that the spin carriers are antiferromagnetically coupled below 10 K; above 10 K, the individual spins are uncorrelated, and [Ce(cot)2]- behaves as an isolated f1 paramagnet. The EPR at 1.5K for Ce2(cot)3 and [Ce(cot)2]- have ground state of MJ= +- 1/2. The LIII edge XANES of Ce(cot)2 (Booth, C.H.; Walter, M.D.; Daniel, M.; Lukens, W.W., Andersen, R.A., Phys. Rev. Lett. 2005, 95, 267202) and 2Ce2(cot)3 over 30-500 K are reported; the Ce(cot)2 XANES spectra show Ce(III) and Ce(IV) signatures up to a temperature of approximately 500 K, whereupon the Ce(IV) signature disappears, consistent with the thermal behavior observed in the melting experiment. The EXAFS of Ce(cot)2 and Ce2(cot)3 are reported at 30 K; the agreement between the molecular parameters for Ce(cot)2 derived from EXAFS and single crystal X-ray diffraction data are excellent. In the case of Ce2(cot)3 no X-ray diffraction data are known to exist, but the EXAFS are consistent with a"triple-decker" sandwich structure. A molecular rationalization is presented for the electronic structure of cerocene having a multiconfiguration ground state that is an admixture of the two configurations Ce(III, 4f1)(cot1.5-)2 and Ce(IV, 4f0)(cot2-)2; the multiconfigurational ground state has profound effects on the magnetic properties and on the nature of the chemical bond in cerocene and, perhaps, other molecules.

  13. Ženy na trhu práce v ČR

    OpenAIRE

    2012-01-01

    This Bachelor's Thesis subject are issues relating to women's participation in the labour market. Theory section of the Thesis addresses labour market and its functioning as a whole, development of the woman's role in society, discrimination, and, last but not least, legislative acts and other norms regulating this field.The second section of the Thesis summarizes results of a survey and finds views on the issue by a small sample of respondents. Based on these results, the Thesis makes conclu...

  14. Rovnost příležitostí na trhu práce

    OpenAIRE

    Bažantová, Silvie

    2016-01-01

    The bachelor thesis is devoted to equal opportunities of women in the labour market. This thesis is divided into theoretical a practical part. The theoretical part surveys the legislation equality of women in the Czech Republic, which is outgoing from legislation of European Union, whose the most important provisions in this respects are the Charter of Fundamental Rights and Freedoms and the Act No. 198/2009 Coll., anti-discrimination Act. The thesis analyses significant provisions in the ...

  15. ZAČLENĚNÍ MENŠIN NA ČESKÉM TRHU PRÁCE

    OpenAIRE

    Pišťák, Zbyněk

    2010-01-01

    The topic of the master thesis is "The inclusion of minorities in the Czech labour market." The main focus is given mainly on Roma and Vietnamese minorities. The inclusion of these minorities into the Czech labour market covers several societal aspects like prevention of criminality, social exclusion and poverty. The master thesis deals in particular with the theoretical analysis of the position of these minorities its social consequences and the possible solutions of connected problems. The ...

  16. Spectroscopic properties of the Ce-doped borate glasses

    Science.gov (United States)

    Kindrat, I. I.; Padlyak, B. V.; Mahlik, S.; Kukliński, B.; Kulyk, Y. O.

    2016-09-01

    The EPR, optical absorption and photoluminescence (emission and excitation) spectra as well as decay kinetics of a series of the Ce-doped glasses with Li2B4O7, LiKB4O7, CaB4O7, and LiCaBO3 compositions have been investigated and analysed. The borate glasses were obtained from the corresponding polycrystalline compounds in the air atmosphere, using standard glass technology. The EPR signals of the isolated Ce3+ and pair Ce3+-Ce3+ centres, coupled by magnetic dipolar and exchange interactions were registered at liquid helium temperatures. The characteristic for glass host broad bands corresponding to the 4f → 5d transitions of the Ce3+centres have been observed in the optical absorption and photoluminescence (emission and excitation) spectra. The obtained luminescence decay curves can be satisfactory described by exponential function with lifetimes in the 19.8-26.1 ns range, which depend on the basic glass composition. The local structure of Ce3+ centres in the investigated glasses has been considered and discussed.

  17. Ca2+-Doped CeBr3 Scintillating Materials

    Energy Technology Data Exchange (ETDEWEB)

    Guss, Paul [NSTec; Foster, Michael E. [SNL; Wong, Bryan M. [SNL; Doty, F. Patrick [SNL; Shah, Kanai [RMD; Squillante, Michael R. [RMD; Shirwadkar, Urmila [RMD; Hawrami, Rastgo [RMD; Tower, Josh [RMD; Yuan, Ding [NSTec

    2014-01-01

    Despite the outstanding scintillation performance characteristics of cerium tribromide (CeBr3) and cerium-activated lanthanum tribromide, their commercial availability and application are limited due to the difficulties of growing large, crack-free single crystals from these fragile materials. This investigation employed aliovalent doping to increase crystal strength while maintaining the optical properties of the crystal. One divalent dopant (Ca2+) was used as a dopant to strengthen CeBr3 without negatively impacting scintillation performance. Ingots containing nominal concentrations of 1.9% of the Ca2+ dopant were grown. Preliminary scintillation measurements are presented for this aliovalently doped scintillator. Ca2+-doped CeBr3 exhibited little or no change in the peak fluorescence emission for 371 nm optical excitation for CeBr3. The structural, electronic, and optical properties of CeBr3 crystals were studied using the density functional theory within the generalized gradient approximation. The calculated lattice parameters are in good agreement with the experimental data. The energy band structures and density of states were obtained. The optical properties of CeBr3, including the dielectric function, were calculated.

  18. CE-SAM: a conversational interface for ISR mission support

    Science.gov (United States)

    Pizzocaro, Diego; Parizas, Christos; Preece, Alun; Braines, Dave; Mott, David; Bakdash, Jonathan Z.

    2013-05-01

    There is considerable interest in natural language conversational interfaces. These allow for complex user interactions with systems, such as fulfilling information requirements in dynamic environments, without requiring extensive training or a technical background (e.g. in formal query languages or schemas). To leverage the advantages of conversational interactions we propose CE-SAM (Controlled English Sensor Assignment to Missions), a system that guides users through refining and satisfying their information needs in the context of Intelligence, Surveillance, and Reconnaissance (ISR) operations. The rapidly-increasing availability of sensing assets and other information sources poses substantial challenges to effective ISR resource management. In a coalition context, the problem is even more complex, because assets may be "owned" by different partners. We show how CE-SAM allows a user to refine and relate their ISR information needs to pre-existing concepts in an ISR knowledge base, via conversational interaction implemented on a tablet device. The knowledge base is represented using Controlled English (CE) - a form of controlled natural language that is both human-readable and machine processable (i.e. can be used to implement automated reasoning). Users interact with the CE-SAM conversational interface using natural language, which the system converts to CE for feeding-back to the user for confirmation (e.g. to reduce misunderstanding). We show that this process not only allows users to access the assets that can support their mission needs, but also assists them in extending the CE knowledge base with new concepts.

  19. Optical properties of {gamma}- and {alpha}-Ce by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Joo Yull, Rhee

    1992-07-20

    A rotating analyzer type ellipsometer with an ultra high vacuum sample chamber was built. The dielectric functions of {gamma}- and {alpha}-Ce were measured in the energy range from 1.5 to 5.4 eV to investigate the role of the 4f electron in the isostructural phase transition. {gamma}- and {alpha}-Ce were made by evaporation of Ce on sapphire substrates at room temperature and 25 K. All measurements were performed inside a UHV chamber at pressures lower than l {times} 10{sup {minus}10}Torr. The measured dielectric functions showed a thickness dependence. The thicker sample has the smaller optical conductivities. Both overlayer thickness and void fraction increase as sample thickness increases. Repeating cooling-heating-cooling or heating-cooling-heating cycles causes the sample surface to become rougher but the relative volume fractions of both phases and the void fraction in the bulk remain unchanged. The optical conductivity increases upon entering the a-phase but the number of electrons per atom, N{sub eff}/N{sub A}, contributing to the optical conductivity does not change. The valence electrons lose oscillator strength in the above energy range due to volume collapse. This reduces N{sub eff}/NA but the increased 4f-sd valence band hybridization exactly compensates the reduced oscillator strength. Therefore the net effects of the {gamma}{yields}{alpha} isostructural phase transition are an increase of optical conductivity and constancy of N{sub eff}/N{sub A}.

  20. Investigation of rhodamine B photocatalytic degradation by Ce3+ doped Bi2WO6%稀土Ce3+掺杂Bi2WO6光催化降解罗丹明B的研究

    Institute of Scientific and Technical Information of China (English)

    王春英; 朱清江; 谷传涛; 石湖泉; 张大超; 余长林

    2015-01-01

    采用水热合成法制备稀土元素Ce3+掺杂Bi2WO6光催剂,通过X射线衍射、场发射电镜扫描、紫外-可见漫反射光谱、N2物理吸附-脱附等手段对合成材料的结构、形貌、光吸收等物理化学性能进行表征,并以染料废水中罗丹明B的降解考察其光催化活性.结果表明,Ce3+掺杂量为0.05%时,其结晶度好、颗粒较均匀、具有较强的可见光吸收性能,且比表面积比纯Bi2WO6提高近10%以上,对罗丹明B的去除效果最好;催化剂用量越高、罗丹明B的初始浓度越低、反应溶液pH值越低、H2O2的浓度越高越有利于Ce/Bi2WO6对罗丹明B的吸附和降解;而阴阳离子的影响各不相同:NO3-、SO42-没有太大的影响; Na+、K+、Ca2+、Mg2+、Cl-的加入均促使的染料的去除;HCO3-抑制了罗丹明B的吸附,但是却促进了光降解.另外,经重复使用3次,光催化降解速率常数并没有降低,表明稀土Ce3+改性Bi2WO6是一种有效稳定的光催化剂.%Rare earth element Ce3+ doped Bi2WO6 was synthesized by hydrothermal method. The physicochemical properties of prepared materials were characterized by XRD, SEM, UV-vis DRS and N2adsorption-desorption. Rhodamine B was used to as the objective pollutant to investigate the photocatalytic activity of Ce/Bi2WO6. As a result, Ce/Bi2WO6 (0.05%) has the optimum phtocatalytic activity to removal rhodamine B, which has good crystalinity, uniform shape and size, strong visible light-responsible property and the higherSBET value (ca. 10%) than pure Bi2WO6. Much more amount of catalyst, less concentration of Rhodamine B, lower pH value of the reaction solution and higher concentration of H2O2 all benefit the adsorption and photodegradation of Rhodamine B by Ce/Bi2WO6. The common inorganic ions showed different effects on Rhodamine B degradation. There was no significantly effect of NO3- and SO42-; but the addition of Na+, K+, Ca2+, Mg2+, Cl- inhibited the removal of the dye. HCO3- reduced the

  1. Ce O{sub 2}-Zr O{sub 2} tetragonal ceramics (Ce-TZP): mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Nono, Maria do Carmo de Andrade [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Laboratorio Associado de Sensores e Materiais

    1994-12-31

    This work presents the development and the characterization of Ce O{sub 2}-stabilized tetragonal Zr O{sub 2} polycrystals (Ce-TZP ceramics), since it is considered candidate material for applications as structural high performance ceramics, an as substitute of some metallic materials. Ce-TZP ceramics attain remarkable increasing in strength and fracture toughness. Sintered ceramics were fabricated from mixtures of powders containing different Ce O{sub 2} content prepared by conventional mechanical technique. It were adopted the bending strength, Vickers hardness and fracture toughness techniques to the determination of the mechanical parameters. These results were discussed and compared to those published in international literature. (author) 11 refs., 10 figs.

  2. Magnetic susceptibility study of Ce{sup 3+} in PbCeA (A=Te, Se, S)

    Energy Technology Data Exchange (ETDEWEB)

    Gratens, X., E-mail: xgratens@gmail.com [Instituto de Fisica, Universidade de Sao Paulo, 05315-970, Sao Paulo (Brazil); Isber, S., E-mail: si00@aub.edu.lb [American University of Beirut, Department of Physics, Bliss Street, PO Box 11-0236, Beirut 1107-2020 (Lebanon); Charar, S., E-mail: salam.charar@iut-nimes.fr [Group d' Etudes des Semiconducteurs (GES), Universite Montpellier II, CC074, 34095 Montpellier Cedex 5 (France); Golacki, Z. [Institute of Physics, Polish Academy of Sciences, Pl.02-668 Warsaw (Poland)

    2012-09-15

    The magnetic susceptibility of Pb{sub 1-x}Ce{sub x}A (A=S, Se and Te) crystals with Ce{sup 3+} concentrations 0.006{<=}x{<=}0.036 was investigated in the temperature range from 2 K to 300 K. The magnetic susceptibility data was found to be consistent with a {sup 2}F{sub 5/2} lowest manifold for Ce{sup 3+} ions with a crystal-field splitting {Delta}=E({Gamma}{sub 8})-E({Gamma}{sub 7}) of about 340 K, 440 K and 540 K for Pb{sub 1-x}Ce{sub x}Te, Pb{sub 1-x}Ce{sub x}Se, and Pb{sub 1-x}Ce{sub x}S, respectively. For all the three compounds the doublet {Gamma}{sub 7} lies below the {Gamma}{sub 8} quadruplet which confirms the substitution of Pb{sup 2+} by Ce{sup 3+} ions in the host crystals. The observed values for the crystal-field splitting are in good agreement with the calculated ones based on the point-charge model. Moreover, the effective Lande factors were determined by X-band ({approx}9.5 GHz), electron paramagnetic measurements (EPR) to be g=1.333, 1.364, and 1.402 for Ce ions in PbA, A = S, Se and Te, respectively. The small difference with the predicted Lande factor g of 10/7 for the {Gamma}{sub 7} (J=5/2) ground state was attributed to crystal-field admixture. - Highlights:: Black-Right-Pointing-Pointer Magnetic susceptibility of Pb{sub 1-x}Ce{sub x}A (A=Te, Se and S). Black-Right-Pointing-Pointer Computed the zero-field splitting of Ce{sup 3+} ion in lead chalcogenides. Black-Right-Pointing-Pointer Explained the existence of four Ce{sup 3+} sites in PbA (A=Te, Se and S).

  3. The NA57 experiment

    CERN Multimedia

    Laurent Guiraud

    1997-01-01

    NA57 is one of the seven experiments (NA44, NA45, NA49, NA50, NA52, WA97/NA57 and WA98) involved in CERN's Heavy Ion programme, which provided evidence for the existence of a new state of matter, the quark-gluon plasma. In this state, quarks, instead of being bound up into more complex particles such as protons and neutrons, are liberated and roam freely. Theory predicts that this state must have existed at about 10 microseconds after the Big Bang, before the formation of matter as we know it today.

  4. The Problems of C-E Public Signs' Translating%The Problems of C-E Public Signs'Translating

    Institute of Scientific and Technical Information of China (English)

    冯煊

    2016-01-01

    With the development of our country, we build up a good relationship with western countries. Public signs are regarded as a symbol of our country.Thus, appropriate translations of the public signs can guarantee a good communication between the Chinese and the international people. However, there are many problems on C-E public signs' translation. This paper gives some advice for C-E public signs' translating under the guidance of Skopostheorie.

  5. 稀土硼化物LaxCe1-xB6亚微米粉的制备及光吸收研究∗%Synthesis and optical absorption prop erties of LaxCe1-xB6 submicron powders

    Institute of Scientific and Technical Information of China (English)

    包黎红; 朝洛蒙; 伟伟; 特古斯

    2015-01-01

    以稀土氧化物La2 O3和CeO2为稀土源,以NaBH4为硼源在真空环境中通过固相反应成功制备出了分散性好的单相三元LaxCe1−xB6亚微米粉。系统研究了掺杂元素La对CeB6物相,微观结构及光吸收性能的影响。实验结果表明, La元素的掺杂没有改变CeB6的物相和晶体结构,而是无序替代了Ce原子晶位。光吸收结果表明,随着La掺杂量的增加LaxCe1−xB6分散液吸收谷波长从620 nm减小到610 nm出现了蓝移现象。%According to original knowledge, lanthanum hexaboride (LaB6) as an excellent thermionic electron emitter is char-acterized by a low work function, a high emission density, and a high brightness. Recently, much attention has been drawn to its another excellent optical properties: strong light absorption in near infrared rays (NIR), and transparency in visible light (VL), which result from the free electron plasmon resonance. However, up to now the optical properties and syntheses of ternary rare-earth hexaborides have been very rarely reported in the literature. In this paper, ternary LaxCe1−xB6 submicron crystallines are successfully synthesized using a solid-state reaction, in which La2O3 and CeO2 are used as rare-earth sources and NaBH4 as boron sources in a continuous vacuum condition. Effects of La doping content on the LaxCe1−xB6 phase composition, microstructure, and optical absorption properties are investigated by X-ray diffraction, scanning electron microscope (SEM), and transmission electron microscope (TEM). It is found that all the synthesized samples are composed of CaB6-type single-phase alloy with a space group P m¯3m at the reaction temperature of 1200 ◦C held by 2 h. The SEM results indicate that the cubic-shaped ternary LaxCe1−xB6 crystals with a mean size of 200 nm are obtained and the energy dispersive spectrometer results confirm that the La atoms are randomly distributed at the lattice sites of CeB6. High resolution transmission

  6. Simultaneous determination of active ingredients in blueberry wine by CE-AD

    Institute of Scientific and Technical Information of China (English)

    Zi Cheng Li; Lang Zhu Chi; Jin Kun Zhu; Yin Yan Zhang; Qing Jiang Wang; Pin Gang He; Yu Zhi Fang

    2011-01-01

    A method based on capillary electrophoresis coupled with amperometric detection (CE-AD) has been developed for the separation and determination of kaempferol, ferulic acid, vanillic acid, caffeic acid, gallic acid and protocatechuic acid in blueberry wine for the first time. In order to get the optimum conditions of separation, the effects of working electrode potential, pH value and concentration of running buffer, separation voltage and injection time on CE-AD were investigated. Under the optimum conditions, the analytes could be separated in Na2B4O7-KH2PO4 buffer at pH 7.8 within 18 min. A 300 μm diameter carbon disk electrode had good current responses at +0.95 V (vs. SCE) for all analytes. The responses were linear with concentrations over three orders of magnitude with detection limits (S/N = 3) at 10-8 g/mL magnitude for the analytes and the recoveries were in the range of 95.8-106.7%. The method could be successfully applied to the analysis of real sample with satisfactory results and therefore recommended for use by the quality control departments of fruit wine producers.

  7. Electroless ternary NiCeP coatings: Preparation and characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Balaraju, J.N., E-mail: jnbalraj@nal.res.in [Surface Engineering Division, CSIR National Aerospace Laboratories, Post Bag No. 1779 Bangalore 560017, Karnataka (India); Chembath, Manju [Surface Engineering Division, CSIR National Aerospace Laboratories, Post Bag No. 1779 Bangalore 560017, Karnataka (India)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer Rare earth element (Ce) has been successfully codeposited in NiP matrix. Black-Right-Pointing-Pointer Surface analysis carried out by XPS showed that the Ce is present in +3 and +4 oxidation state. Black-Right-Pointing-Pointer Palladium stability test indicated that the Ce salts in electroless nickel bath has reduced the stability. Black-Right-Pointing-Pointer Cerium codeposition in NiP matrix has increased the microhardness both in as-plated and annealed conditions. Black-Right-Pointing-Pointer Higher thermal stability has been obtained by Ce incorporation. - Abstract: Electroless ternary NiCeP deposits were prepared from alkaline citrate bath containing nickel sulphate, cerium chloride and sodium hypophosphite. Concentration of rare earth cerium was varied from 1 to 2 g/L to obtain ternary deposits containing variable Ce and P contents. The influence of cerium on the deposit properties was analysed. The deposit exhibited a maximum cerium content of 6.2 {+-} 0.1 wt.% when the cerium chloride concentration was 2 g/L. The result of the Pd stability test showed that the stability of the bath was reduced due to Ce salt addition. The microhardness measurements made on both as-plated and heat treated samples exhibited a peak hardness of 1006 {+-} 11 VHN for cerium concentration of 1.5 g/L. The concept of kinetic strength analysis was proved to be applicable only for binary and not for ternary alloys due to multistep deposition mechanism with different kinetic energies. X-ray diffraction (XRD) patterns of as-plated and heat treated samples revealed peaks corresponding to Ni (1 1 1) and nickel phosphide (Ni{sub 3}P). Higher amount of Ce incorporation in NiP matrix increased the crystallisation temperature of the deposit which could be due to the suppression of nickel crystallisation prior to Ni{sub 3}P compound formation and thus increasing the activation energy for the formation of stable phases. Surface compositional analysis

  8. The CE3R Network: current status and future perspectives

    Science.gov (United States)

    Lenhardt, Wolfgang; Pesaresi, Damiano; Živčić, Mladen; Costa, Giovanni; Kuk, Kresimir; Bondár, István; Duni, Llambro; Spacek, Petr

    2016-04-01

    In order to improve the monitoring of seismic activities in the border regions and to enhance the collaboration between countries and seismological institutions in Central Europe, the Environment Agency of the Slovenian Republic (ARSO), the Italian National Institute for Oceanography and Experimental Geophysics (OGS), the University of Trieste (UniTS) and the Austrian Central Institute for Meteorology and Geodynamics (ZAMG) established in 2001 the "South Eastern Alps Transfrontier Seismological Network". In May 2014 ARSO, OGS, UniTS and ZAMG agreed to formalize the transfrontier network, to name it "Central and East European Earthquake Research Network", (CE3RN or CE3R Network) in order to locate it geographically since cross-border networks can be established in other areas of the world and to expand their cooperation, including institutions in other countries. The University of Zagreb (UniZG) joined CE3RN in October 2014. The Kövesligethy Radó Seismological Observatory (KRSZO) of the Hungarian Academy of Sciences joined CE3RN in October 2015. The Institute of Geosciences, Energy, Water and Environment (IGEWE) of the Polytechnic University of Tirana joined CE3RN in November 2015. The Institute of Physics of the Earth (IPE) of the Masaryk University in Brno joined CE3RN in November 2015. CE3RN Parties intend to formalize and possibly extend their ongoing cooperation in the field of seismological data acquisition, exchange and use for seismological and earthquake engineering and civil protection purposes. The purpose of this cooperation is to retain and expand the existing cross-border network, specify the rules of conduct in the network management, improvements, extensions and enlargements, enhance seismological research in the region, and support civil protection activities. Since the formal establishment of CE3RN, several common projects have been completed, like the SeismoSAT project for the seismic data center connection over satellite funded by the Interreg

  9. The role of calcification for staging cystic echinococcosis (CE)

    Energy Technology Data Exchange (ETDEWEB)

    Hosch, Waldemar; Kauffmann, Guenter W. [University Hospital Heidelberg, Department of Radiology, Heidelberg (Germany); Stojkovic, Marija; Junghanss, Thomas [University Hospital of Heidelberg, Section of Clinical Tropical Medicine, Heidelberg (Germany); Jaenisch, Thomas [University Hospital of Heidelberg, Section of Clinical Tropical Medicine, Heidelberg (Germany); University Hospital of Heidelberg, Section of Biostatistics and Epidemiology, Heidelberg (Germany)

    2007-10-15

    The prevalence of calcified cysts and the significance of calcification as a sign of cyst inactivity in cystic echinococcosis (CE) was evaluated. Seventy-eight patients (36 females, 42 males, mean age 40.8 {+-} 16.9 years) with CE, having a total of 137 abdominal cysts (116 hepatic, three splenic, one renal and 17 peritoneal cysts), were diagnosed and followed-up by ultrasound during and after albendazole treatment or as part of the watch-and-wait approach recording changes in the cyst wall and content. In 48 patients with 94 cysts, computed tomography (CT) imaging was additionally available and was correlated with ultrasound findings. Cyst wall calcification was classified into (1) ''sprinkled'', (2) ''eggshell-like'', and (3) ''circular''. Calcification of the cyst wall and/or cyst content was detected in 67 echinococcal cysts (48.9% of all cysts) in 39 patients (15 females, 24 males, mean age 40.8 {+-} 14.8 years). Of the total of 67 calcified cysts, only 23 were compatible with WHO type CE5, 18 with WHO type CE4. Judged by cyst content, the remaining 26 were of WHO type CE1, CE2 and CE3 (n = 1, n = 8, and n = 17, respectively). During a mean period of 34.3 months ({+-}21.3 months) the majority of cysts (n = 32) did not exhibit any change in cyst content and wall properties. Fourteen cysts showed signs of progressive involution, five cysts (all of WHO type CE3) of renewed activity defined by recurring fluid collection. In 16 cysts, no follow-up was available due to surgery or drop out. Calcification of the cyst is not restricted to the inactive WHO cyst types CE4 and CE5, but occurs in all stages and in up to 50% of cysts. The completeness and, most importantly, the stability of consolidation of cyst content over time predicts cyst inactivity more reliably. (orig.)

  10. Effects of CeO2 Support Facets on VOx/CeO2 Catalysts in Oxidative Dehydrogenation of Methanol

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yan; Wei, Zhehao; Gao, Feng; Kovarik, Libor; Peden, Charles HF; Wang, Yong

    2014-05-13

    CeO2 supports with dominating facets, i.e., low index (100), (110) and (111) facets, are prepared. The facet effects on the structure and catalytic performance of supported vanadium oxide catalysts are investigated using oxidative dehydrogenation of methanol as a model reaction. In the presence of mixed facets, Infrared and Raman characterizations demonstrate that surface vanadia species preferentially deposit on CeO2 (100) facets, presumably because of its higher surface energy. At the same surface vanadium densities, VOx species on (100) facets show better dispersion, followed by (110) and (111) facets. The VOx species on CeO2 nanorods with (110) and (100) facets display higher activity and lower apparent activation energies compared to that on CeO2 nanopolyhedras with dominating (111) facets and CeO2 nanocubes with dominating (100) facets. The higher activity for VOx/CeO2(110) might be related to the more abundant oxygen vacancies present on the (110) facets, evidenced from Raman spectroscopic measurements.

  11. SYNTHESIS OF CeAPO- 5 MOLECULAR SIEVE%CeAPO-5分子筛的合成

    Institute of Scientific and Technical Information of China (English)

    张岩; 秦海莉; 高平强

    2010-01-01

    以三乙胺为模板剂、利用水热晶化法合成CeAPO-5分子筛,系统考察了铝源、水量以及晶化条件对CeAPO-5分子筛合成的影响.研究结果表明:铝源是决定CeAPO-5分子筛合成及结构的关键组分之一,拟薄水铝石AlO(OH)是合成CeAPO-5分子筛的比较合适的铝源;在n(P2O5)∶n(Al2O3)∶n(Et3N)∶n(H2O)∶n(Ce2O3)=1∶0.8∶0.26∶60∶0.5;晶化温度150℃;晶化72小时的条件下,可合成CeAPO-5分子筛.

  12. Role of surface Ni and Ce species of Ni/CeO2 catalyst in CO2 methanation

    Science.gov (United States)

    Zhou, Guilin; Liu, Huiran; Cui, Kaikai; Jia, Aiping; Hu, Gengshen; Jiao, Zhaojie; Liu, Yunqi; Zhang, Xianming

    2016-10-01

    CeO2, which was used as support to prepare mesoporous Ni/CeO2 catalyst, was prepared by the hard-template method. The prepared NiO/CeO2 precursor and Ni/CeO2 catalyst were studied by H2-TPR, in-situ XPS, and in-situ FT-IR. The catalytic properties of the prepared Ni/CeO2 catalyst were also investigated by CO2 catalytic hydrogenation methanation. H2-TPR and in-situ XPS results showed that metal Ni species and surface oxygen vacancies could be formed by H2 reduction. In-situ FT-IR and in-situ XPS results indicated that CO2 molecules could be reduced by active metal Ni species and surface oxygen vacancies to generate active CO species and promote CO2 methanation. The Ni/CeO2 catalyst presented the high CO2 methanation activity, and CO2 conversion and CH4 selectivity reached 91.1% and 100% at 340 °C and atmospheric pressure.

  13. Self-healing effect of ceria electrodeposited thin films on stainless steel in aggressive 0.5 mol/L NaCl aqueous solution

    Institute of Scientific and Technical Information of China (English)

    Desislava Guergova; Emilia Stoyanova; Dimitar Stoychev; Ivalina Avramova; Plamen Stefanov

    2015-01-01

    The self-healing effect of electrochemically deposited CeO2-Ce2O3 films on stainless steel OC404 (SS) in 0.5 mol/L NaCl solution was studied. It was established that the corrosion potential of the steel, after covering it with CeO2-Ce2O3 layer and thermal treatment (i.e. potential of the system CeO2-Ce2O3/SSt.t.), was shifted sharply to a considerably more positive value, while the corro-sion current was reduced noticeably. The X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and scan-ning electron microscopy (SEM) analyses on the observed scratched surface area of the system CeO2-Ce2O3/SSt.t., after exposure of investigated specimens to 0.5 mol/L NaCl corrosion media, showed partial accumulation of ceria, as well as remarkable increase in the concentrations of oxides of Al, Cr and Fe, on the mechanically revealed steel surface. On the basis of the obtained results one could conclude that the secondary passive oxide/hydroxide films, formed after a definite time interval of exposure to corrosion media, acted as barriers, hindering the corrosion processes in active zones. A hypothesis was put forward about the mechanism of self-repairing oxide layers on the steel surface and their corrosion protection effect respectively.

  14. Coexistence phenomenon of Ce(3+)-Ce(4+) and Eu(2+)-Eu(3+) in Ce/Eu co-doped LiBaB9O15 phosphor: luminescence and energy transfer.

    Science.gov (United States)

    Li, Ting; Li, Panlai; Wang, Zhijun; Xu, Shuchao; Bai, Qiongyu; Yang, Zhiping

    2017-02-01

    Ce/Eu-doped LiBaB9O15 (LBB) samples were prepared via conventional high temperature solid state reactions. The XRD patterns, crystal structures, luminescence properties, and decay times were investigated systematically. Ce(3+) ions exist in LBB:xCe(3+) that were synthesized in a reducing atmosphere and in an air atmosphere. However, we observed Eu(2+) ions in LBB:yEu(2+) in a reducing atmosphere and Eu(3+) ions in LBB:zEu(3+) in an air atmosphere. LBB:0.05Ce(3+),yEu(2+) phosphors synthesized in a reducing atmosphere only possess Ce(3+) and Eu(2+) and exhibit a broad excitation band ranging from 350 to 425 nm. A reduction phenomenon of Eu(3+) → Eu(2+) and coexistence of Ce(4+), Ce(3+), Eu(2+) and Eu(3+) were observed when LBB:0.05Ce,wEu phosphors were synthesized in an air atmosphere. There are three processes in LBB:0.05Ce,wEu, i.e., energy transfers from Ce(3+) to Eu(2+) and from Eu(2+) to Eu(3+), and metal-metal charge transfer (MMCT) between Ce(3+) and Eu(3+). Moreover, the MMCT process is dominant in LBB:0.05Ce,wEu due to less efficient energy transfer from Ce(3+) to Eu(2+). Moreover, the CIE coordinates of LBB:0.05Ce,wEu vary systematically from light blue (0.313, 0.129) to red (0.589, 0.315) for LBB:0.05Ce(3+),wEu synthesized in air with the changes in Eu ion concentration. Thus, we can control the color by controlling the synthesis atmospheres.

  15. Production of hydrogen by partial oxidation of methanol over Au/CeO2, Au-Pd/CeO2 and Pd/CeO2 catalysts%Au/CeO2、Pd/CeO2和Au-Pd/CeO2催化剂甲醇部分氧化制氢性能的研究

    Institute of Scientific and Technical Information of China (English)

    李苑; 罗来涛

    2009-01-01

    采用沉积沉淀法制备了Au/CeO2、Pd/CeO2和Au-Pd/CeO2催化剂,研究了催化剂的甲醇部分氧化制氢性能,并运用XRD、UV-Vis、TPR、H2-TPD和CO-TPD等手段对催化剂进行了表征.结果表明,与Pd/CeO2和Au/CeO2相比,Au-Pd/CeO2双金属催化剂显示出较高的催化活性和较高的氢产率,这是由于Au和Pd的相互作用减少了Pd对反应产物H2的吸附,有利于活性中心再生,且减小了H2的深度氧化,同时Au和Pd相互作用使金粒子较稳定、不易聚集,有利于高温时H2选择性的稳定.

  16. Comparison of energy structure and spectral properties of Ce:LaAlO3 and Ce:Lu2(SiO4)O

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Undoped LaAlO3 and 1 at.%Ce:LaAlO3 single crystals were grown by the Czochralski process.Absorption and fluorescence spectra were measured at room temperature.Detailed energy levels structure of Ce:LaAlO3 was determined.In this paper,two viewpoints were provided.The first one is:the energy levels structure of Ce:LaAlO3 is very similar to that of Ce:Lu2(SiO4)O which is a well-known scintillator.In the energy levels structure of Ce:LaAlO3 and Ce:Lu2(SiO4)O,the lowest 5d energy level of Ce 3+ is located below the bottom of the conduction band of host crystal and the other higher 5d energy levels of Ce 3+ are located above the bottom of the conduction band of host crystal.The second one is:Ce:LaAlO3 single crystal may not be suitable for scintillation application;by comparing the energy levels structures of Ce:LaAlO3 and Ce:Lu2(SiO4)O,the large energy difference(1.13 eV)between the two lowest 5d energy levels of Ce 3+ in LaAlO3 is a crucial factor that causes the luminescence quenching.

  17. Comparison between the Oxygen Reduction Reaction Activity of Pd5Ce and Pt5Ce

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Zheng, Jian; Rizzi, Gian Andrea;

    2015-01-01

    confirmed that in our sample, L-Pd5Ce is the dominant phase, both in the bulk and the outermost layers, while a H-Pd5Ce-like phase is also present as a minor component far below the surface. Electrochemical ORR assessments show that the Pd overlayer in Pd5Ce is less active than the polycrystalline Pd sample...

  18. LiCe9Mo16O35

    Directory of Open Access Journals (Sweden)

    Patrick Gougeon

    2012-03-01

    Full Text Available The structure of lithium nonacerium hexadecamolybdenum pentatridecaoxide, LiCe9Mo16O35, is isotypic with LiNd9Mo16O35 [Gougeon Gall, Cuny, Gautier, Le Polles, Delevoye & Trebosc (2011. Chem. Eur. J. 17, 13806–13813]. It is characterized by Mo16O26iO10a units (where i = inner and a = apical containing Mo16 clusters that share some of their O atoms to form infinite molybdenum cluster chains running parallel to the b axis and separated by Li+ and Ce3+ cations. The Mo16 cluster units are centred at Wyckoff positions 2c and have point-group symmetry 2/m. The Li+ atom, in a flattened octahedron of O atoms, is in a 2a Wyckoff position with 2/m symmetry. The Ce3+ cations have coordination numbers to the O atoms of 6, 9 or 10. Two Ce, two Mo and five O atoms lie on sites with m symmetry (Wyckoff site 4i, and one Ce and one O atom on sites with 2/m symmetry (Wyckoff sites 2b and 2d, respectively.

  19. Photoemission spectra of CeAl[sub 3], CeBe[sub 13], CeSi[sub 2], and CeCu[sub 2]Si[sub 2]: Weights and widths of the 4[ital f] emission features

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, J.M. (Physics Department, University of California, Irvine, California 92717 (United States)); Arko, A.J.; Joyce, J.J.; Blyth, R.I.R.; Bartlett, R.J.; Canfield, P.C.; Fisk, Z. (Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)); Riseborough, P.S. (Physics Department, Polytechnic University, Brooklyn, New York 11201 (United States))

    1993-06-15

    We present valence-band photoemission spectra for CeAl[sub 3], CeBe[sub 13], CeSi[sub 2], CeCu[sub 2]Si[sub 2], and related conventional rare-earth counterpart compounds, taken at photon energies corresponding to the giant 4[ital d] resonance with resolution [similar to]150 meV. We take into account the 5[ital d] emission, which comprises 30% of the valence-band emission at the 4[ital d] resonance. We compare the resulting 4[ital f] emission to the predictions of the Anderson impurity model calculated in a low-order 1/[ital N] expansion, and including spin-orbit, crystal-field, and finite Coulomb correlation effects. The calculation gives order-of-magnitude fits to the data, but underestimates the spectral weight near the Fermi level by a factor of 2 and overestimates the width of the main [ital f] emission at 2 eV by a factor of 4. We argue that Ce photoemission remains an open problem and discuss several experimental and theoretical issues which need to be resolved to make further progress.

  20. An Update on NiCE Support for BISON

    Energy Technology Data Exchange (ETDEWEB)

    McCaskey, Alex [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Billings, Jay Jay [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deyton, Jordan H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wojtowicz, Anna [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-01

    The Nuclear Energy Advanced Modeling and Simulation program (NEAMS) from the Department of Energy s Office of Nuclear Energy has funded the development of a modeling and simulation workflow environment to support the various codes in its nuclear energy scientific computing toolkit. This NEAMS Integrated Computational Environment (NiCE) provides extensible tools and services that enable efficient code execution, input generation, pre-processing visualizations, and post-simulation data analysis and visualization for a large portion of the NEAMS Toolkit. A strong focus for the NiCE development team throughout FY 2015 has been support for the Multiphysics Object Oriented Simulation Environment (MOOSE) and the NEAMS nuclear fuel performance modeling application built on that environment, BISON. There is a strong desire in the program to enable and facilitate the use of BISON throughout nuclear energy research and industry. A primary result of this desire is the need for strong support for BISON in NiCE. This report will detail improvements to NiCE support for BISON. We will present a new and improved interface for interacting with BISON simulations in a variety of ways: (1) improved input model generation, (2) embedded mesh and solution data visualizations, and (3) local and remote BISON simulation launch. We will also show how NiCE has been extended to provide support for BISON code development.

  1. ZrCoCe Getter Films for MEMS Vacuum Packaging

    Science.gov (United States)

    Xu, Yaohua; Cui, Jiandong; Cui, Hang; Zhou, Hao; Yang, Zhimin; Du, Jun

    2016-01-01

    In order to specifically support the technology trend of increased miniaturization of micro electro mechanical systems (MEMS) devices, highly porous ZrCoCe non-evaporable getter (NEG) film has been produced by direct current magnetron sputtering from a preformed ZrCoCe alloy target. Scanning electron microscopy and x-ray diffraction analysis indicated that the ZrCoCe film is constructed with porous columnar crystals, which are further built up with assembled ZrCoCe amorphous or nanocrystalline grains with an average grain size of 5 nm. Gas sorption investigation shows that this film can be activated at a low temperature of 300°C for 30 min and has excellent stable sorption characteristics. Sorption properties can be further improved with elevating activation temperatures due to nanocrystals growing and amorphous regions crystallizing. The capability of ZrCoCe films to withstand wafer physical or chemical cleaning processes is investigated, indicating their compatibility with MEMS vacuum packaging and the appropriate way to store them.

  2. Angelite: Paziteli na vhoda

    Directory of Open Access Journals (Sweden)

    Gerov Georgi

    2009-01-01

    Full Text Available (bugarski Statijata prosledjava ikonografskata evoljucija na izobraženijata na arhangelite Mihail i Gavriil, pomesteni pri vhoda na pravoslavnija hram. Povraten moment v neja e 13 vek. Togava arhangel Mihail započva da se izobrazjava kato voin. S tova apotropejnite mu funkcii namirat adekvaten vizualen izraz. K'm kraja na stoletieto arhangel Gavriil započva da se izobrazjava kato pisar - ikonografija, kojato šče b'de dorazvita i utv'rdena prez 14 vek. Prez postvizantijskata epoha v obraza na Mihail se pojavjavat elementi, koito akcentirat v'rhu roljata mu na psihopomp.

  3. Magnetic, thermal and electronic properties of Ce{sub 11}Ni{sub 4}In{sub 9} and CeNi{sub 9}In{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Szytuła, A., E-mail: andrzej.szytula@uj.edu.pl [Marian Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków (Poland); Baran, S.; Penc, B. [Marian Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków (Poland); Przewoźnik, J. [Department of Solid State Physics, Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków (Poland); Winiarski, A. [August Chełkowski Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Tyvanchuk, Yu.; Kalychak, Ya.M. [Department of Analytical Chemistry, Ivan Franko National University of Lviv, Kyryla and Mephodiya 6, 79005 Lviv (Ukraine)

    2014-03-15

    Highlights: • Basis on the X-ray data the crystal structure of Ce{sub 11}Ni{sub 4}In{sub 9} and CeNi{sub 9}In{sub 2} compounds determined. • In Ce{sub 11}Ni{sub 4}In{sub 9} the Ce magnetic moments order at low temperatures, where in CeNi{sub 9}In{sub 2} not detected localized moment. • Magnetic and specific heat data of Ce{sub 11}Ni{sub 4}In{sub 9} indicate two phase transitions at 5 and 16.5 K. • XPS spectra indicate for both compounds sizable hybridization of the Ce4f electrons with conduction band. • For CeNi{sub 9}In{sub 2} the existence of Ce3d{sup 9}4f{sup 0} configuration indicates the mixed-valence state. -- Abstract: Crystal structure, magnetic, thermal and electronic properties of Ce{sub 11}Ni{sub 4}In{sub 9} and CeNi{sub 9}In{sub 2} compounds were investigated by means of X-ray diffraction, magnetic, calorimetric and X-ray photoelectron spectroscopy measurements. Ce{sub 11}Ni{sub 4}In{sub 9} crystallizes in the orthorhombic Nd{sub 11}Pd{sub 4}In{sub 9}-type structure (space group Cmmm) while CeNi{sub 9}In{sub 2} crystallizes in the YNi{sub 9}In{sub 2}-type structure (space group P4/mbm) (in which Ce atoms occupy only one Wyckoff position). Magnetic and specific heat measurements indicate that in Ce{sub 11}Ni{sub 4}In{sub 9} the Ce magnetic moment orders below 16.5 K, while in CeNi{sub 9}In{sub 2} it does not carry a localized moment. Our data indicate that Ni atoms are likely non-magnetic in both compounds. The XPS spectra of the valence band and the core-level are reported. The contributions to the density of states at E{sub F} are dominated by the Ni3d states. The XPS Ce3d data indicate sizable hybridization of the Ce-4f electrons with conduction band for both compounds. The existence in CeNi{sub 9}In{sub 2} of Ce3d{sup 9}4f{sup 0} configuration indicates a mixed-valence system. The core-level Ni2p{sub 3/2} spectra indicate incomplete Ni3d band filling in this compound.

  4. Calculation the Efficiencies of LaBr3 (Ce) Detector for γRay Produced by Gaseousβ+ Particle Annihilation in MB Beaker by MC Software%用MC软件模拟计算LaBr3(Ce)探测器对MB容器中气态β+粒子湮灭γ光子的探测效率

    Institute of Scientific and Technical Information of China (English)

    刘跃龙; 屈国普; 赵越; 刘跃勇

    2011-01-01

    The paper used the MCNPX software to calculate the efficiencies and counting rate of a same size of LaBr3 ( Ce) scintillation crystals detector for β+ particle in different size of MB Beaker, and different size of La-Br3(Ce) scintillation crystals detector for same MB Beaker, and same size of LaBr3(Ce) scintillation crystals detector but in different depth in the same MB Beaker. Based on the result, the optimal volume of MB Beaker and the optimal depth in MB Beaker was assured,then compared with the data attained in analog computation for NaI( Tl) detector,The comparison result shows that the efficiencies of LaBr3 ( Ce) scintillation crystals detector are more than Nal(Tl) detector.%用蒙特卡罗软件MCNPX版本模拟计算了同一尺寸的溴化镧探测器对不同体积的MB容器中β+粒子的探测效率和计数率,以及不同尺寸的探测器对同一MB容器、同一探测器在同一体积的MB容器中处于不同深度时对β+粒子的探测效率和计数率,根据计算结果,确定了MB容器的最佳体积和探测器在MB容器中的最佳位置,并和NaI(Tl)探测器模拟的结果进行了比较,结果显示,LaBr3 (Ce)探测器对MB容器中β+粒子的探测效率比NaI(Il)要高.

  5. Mixed cerium-platinum oxides: Electronic structure of [CeO]Ptn (n = 1, 2) and [CeO2]Pt complex anions and neutrals

    Science.gov (United States)

    Ray, Manisha; Kafader, Jared O.; Topolski, Josey E.; Jarrold, Caroline Chick

    2016-07-01

    The electronic structures of several small Ce-Pt oxide complexes were explored using a combination of anion photoelectron (PE) spectroscopy and density functional theory calculations. Pt and Pt2 both accept electron density from CeO diatomic molecules, in which the cerium atom is in a lower-than-bulk oxidation state (+2 versus bulk +4). Neutral [CeO]Pt and [CeO]Pt2 complexes are therefore ionic, with electronic structures described qualitatively as [CeO+2]Pt-2 and [CeO+]Pt2-, respectively. The associated anions are described qualitatively as [CeO+]Pt-2 and [CeO+]Pt2-2, respectively. In both neutrals and anions, the most stable molecular structures determined by calculations feature a distinct CeO moiety, with the positively charged Ce center pointing toward the electron rich Pt or Pt2 moiety. Spectral simulations based on calculated spectroscopic parameters are in fair agreement with the spectra, validating the computationally determined structures. In contrast, when Pt is coupled with CeO2, which has no Ce-localized electrons that can readily be donated to Pt, the anion is described as [CeO2]Pt-. The molecular structure predicted computationally suggests that it is governed by charge-dipole interactions. The neutral [CeO2]Pt complex lacks charge-dipole stabilizing interactions, and is predicted to be structurally very different from the anion, featuring a single Pt-O-Ce bridge bond. The PE spectra of several of the complexes exhibit evidence of photodissociation with Pt- daughter ion formation. The electronic structures of these complexes are related to local interactions in Pt-ceria catalyst-support systems.

  6. Transverse wobbling motion in $^{134}$Ce and $^{136}$Nd

    CERN Document Server

    Petrache, C M

    2016-01-01

    The existence of one-phonon and possible two-phonon transverse wobbling bands is proposed for the first time in two even-even nuclei, $^{134}$Ce and $^{136}$Nd. The predominant $E2$ character of the $\\Delta I = 1$ transitions connecting the one-phonon wobbling band in $^{134}$Ce to the two-quasiparticle yrast band supports the wobbling interpretation. The extracted wobbling frequencies decrease with increasing spin, indicating the transverse character of the wobbling motion, with the angular momenta of the two quasiparticles aligned perpendicular to the axis of collective rotation. A candidate for two-phonon wobbling motion is also proposed in $^{136}$Nd. The wobbling frequencies calculated in the harmonic frozen approximation are in good agreement with the experimental ones for both the$^{134}$Ce and $^{136}$Nd nuclei.

  7. Beam fanning effect and image storage in Ce: KNSBN crystal

    Institute of Scientific and Technical Information of China (English)

    LI PanLai; GUO QingLin; WANG ZhiJun; PANG LiBin; LIANG BaoLai

    2007-01-01

    A non-synchronously-numerating experimental system is applied in this research. The effect of the incident beam intensity Ⅰ and the beam incident angle θ on beam fanning effect is investigated with a singular beam incident on Ce:KNSBN crystal. The results show that the beam fanning effect strongly depends on Iand θ. The threshold effect of/for the beam fanning in Ce:KNSBN crystal is observed, and the threshold intensity of incident beam keeps the same value of 38.2 mW/cm2 for different θ, and the steady beam fanning intensity Ifsat reaches a peak at θ=15° under the same Ⅰ. In addition, the effect of the incident beam modulated on the beam fanning noise and holographic storage in Ce:KNSBN crystal is studied. And the results suggest that the beam fanning noise is effectively suppressed, and the quality of the reappearance image is greatly improved.

  8. Homoleptic Ce(III) and Ce(IV) Nitroxide Complexes: Significant Stabilization of the 4+ Oxidation State

    Energy Technology Data Exchange (ETDEWEB)

    Bogart, Justin A.; Lewis, Andrew J.; Medling, Scott A.; Piro, Nicholas A.; Carroll, Patrick J.; Booth, Corwin H.; Schelter, Eric J.

    2014-06-25

    Electrochemical experiments performed on the complex Ce-IV[2-((BuNO)-Bu-t)py](4), where [2-((BuNO)-Bu-t)py](-) = N-tert-butyl-N-2-pyridylnitroxide, indicate a 2.51 V stabilization of the 4+ oxidation state of Ce compared to [(Bu4N)-Bu-n](2)[Ce(NO3)(6)] in acetonitrile and a 2.95 V stabilization compared to the standard potential for the ion under aqueous conditions. Density functional theory calculations suggest that this preference for the higher oxidation state is a result of the tetrakis(nitroxide) ligand framework at the Ce cation, which allows for effective electron donation into, and partial covalent overlap with, vacant 4f orbitals with delta symmetry. The results speak to the behavior of CeO2 and related solid solutions in oxygen uptake and transport applications, in particular an inherent local character of bonding that stabilizes the 4+ oxidation state. The results indicate a cerium(IV) complex that has been stabilized to an unprecedented degree through tuning of its ligand-field environment.

  9. Ce Core-Level Spectroscopy, and Magnetic and Electrical Transport Properties of Lightly Ce-Doped YCoO3

    Science.gov (United States)

    Kobayashi, Yoshihiko; Koike, Tsuyoshi; Okawa, Mario; Takayanagi, Ryohei; Takei, Shohei; Minohara, Makoto; Kobayashi, Masaki; Horiba, Koji; Kumigashira, Hiroshi; Yasui, Akira; Ikenaga, Eiji; Saitoh, Tomohiko; Asai, Kichizo

    2016-11-01

    We have investigated the Ce and Co core level spectroscopy, and the magnetic and electrical transport properties of lightly Ce-doped YCoO3. We have successfully synthesized single-phase Y1-xCexCoO3 for 0.0 ≤ x ≤ 0.1 by the sol-gel method. Hard X-ray photoelectron and X-ray absorption spectroscopy experiments reveal that the introduced Ce ions are tetravalent, which is considered to be the first case of electron doping into bulk trivalent Co oxides with perovskite RECoO3 (RE: rare-earth element or Y) caused by RE site substitution. The magnitude of the effective magnetic moment peff obtained from the temperature dependence of magnetic susceptibility χ(T) at higher temperatures is close to that for high-spin Co2+ introduced by the Ce doping, implying that the electrons doped into the Co site induce Co2+ with a high-spin state. For x = 0.1, ferromagnetic ordering is observed below about 7 K. Electrical transport properties such as resistivity and thermoelectric power show that negative electron-like carriers are introduced by Ce substitution.

  10. Fabrication and characterization of spark plasma sintered Ce:LuAG ceramic for scintillation application

    Science.gov (United States)

    Kumar, S. Arun; Senthilselvan, J.

    2016-05-01

    Rare earth Cerium doped Lutetium Aluminum Garnet (Ce:LuAG) ceramics are widely used as phosphor material in medical imaging and high-energy physics. Due to its technological importance, an attempt has been made to fabricate Ce:LuAG ceramics by using spark plasma sintering (SPS) technique. XRD patterns of SPS sintered Ce:LuAG ceramics reveals a mixed LuAG and CeO2 (antisite defect) phases. The microstructures of SPS sintered Ce:LuAG ceramics shows limited densification, inappropriate compaction of particles and existence of residual pores, voids between the grain boundaries affects the transparency of Ce:LuAG ceramics. Relative density and hardness of post sintered Ce:LuAG ceramic is also determined. The effect of Ce3+ doping concentration and sintering temperature on optical luminescence behavior of Ce:LuAG ceramic is presented.

  11. Ergonomický audit na vysoké škole

    OpenAIRE

    Kazarian, Anna

    2016-01-01

    Diplomová práce se zabývá ergonomickým auditem pracoviště a pracovního prostředí na vysoké škole. Na začátku práce jsou rozebrány faktory, které působí na studenty a vědeckovýzkumné pracovníky, se zaměřením na jejich vliv na zdraví a psychiku. Pozornost je věnována zejména vlivu teplotně-vlhkostních parametrů ovzduší, koncentraci oxidu uhličitého, osvětlení a vybavení studoven a kancelářských místnosti. Dále je věnována pozornost úrovni přizpůsobení pracovních podmínek studentům a zaměstnanců...

  12. Sensitive redox speciation of neptunium by CE-ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Stoebener, Nils; Amayri, Samer; Gehl, Aaron; Kaplan, Ugras; Malecha, Kurtis; Reich, Tobias [Johannes Gutenberg-Universitaet Mainz, Institute of Nuclear Chemistry, Mainz (Germany)

    2012-11-15

    Capillary electrophoresis (CE) was used to separate the neptunium oxidation states Np(IV) and Np(V), which are the only oxidation states of Np that are stable under environmental conditions. The CE setup was coupled to an inductively coupled plasma mass spectrometer (Agilent 7500ce) using a Mira Mist CE nebulizer and a Scott-type spray chamber. The combination of the separation capacity of CE with the detection sensitivity of inductively coupled plasma mass spectrometry (ICP-MS) allows identification and quantification of Np(IV) and Np(V) at the trace levels expected in the far field of a nuclear waste repository. Limits of detection of 1 x 10{sup -9} and 5 x 10{sup -10} mol L{sup -1} for Np(IV) and Np(V), respectively, were achieved, with a linear range from 10{sup -9} to 10{sup -6} mol L{sup -1}. The method was applied to study the redox speciation of the Np remaining in solution after interaction of 5 x 10{sup -7} mol L{sup -1} Np(V) with Opalinus Clay. Under mildly oxidizing conditions, a Np sorption of 31% was found, with all the Np remaining in solution being Np(V). A second sorption experiment performed in the presence of Fe{sup 2+} led to complete sorption of the Np onto the clay. After desorption with HClO{sub 4}, a mixture of Np(IV) and Np(V) was found in solution by CE-ICP-MS, indicating that some of the sorbed Np had been reduced to Np(IV) by Fe{sup 2+}. (orig.)

  13. Eletroforese capilar acoplada à espectrometria de massas (CE-MS: vinte anos de desenvolvimento Capillary electrophoresis coupled to mass spectrometry (CE-MS: twenty years of development

    Directory of Open Access Journals (Sweden)

    Nilson Antonio Assunção

    2008-01-01

    Full Text Available CE-MS has been increasingly used for analysis of a vast array of compounds. This article reviews the different electrophoretic modes, interfaces and mass analyzers that are commonly used in the CE-MS coupling, as well as the technique advantages and performance characteristics. A large compilation of CE-MS applications is also presented. Therefore, this review is both a guide for beginners and a collection of key references for people who are familiar to the technique. Furthermore, this is the first CE-MS review published in a Brazilian journal and marks the installation of the first two commercial CE-MS units in Sao Paulo State.

  14. Pd/CeO2/SiC Chemical Sensors

    Science.gov (United States)

    Lu, Weijie; Collins, W. Eugene

    2005-01-01

    The incorporation of nanostructured interfacial layers of CeO2 has been proposed to enhance the performances of Pd/SiC Schottky diodes used to sense hydrogen and hydrocarbons at high temperatures. If successful, this development could prove beneficial in numerous applications in which there are requirements to sense hydrogen and hydrocarbons at high temperatures: examples include monitoring of exhaust gases from engines and detecting fires. Sensitivity and thermal stability are major considerations affecting the development of high-temperature chemical sensors. In the case of a metal/SiC Schottky diode for a number of metals, the SiC becomes more chemically active in the presence of the thin metal film on the SiC surface at high temperature. This increase in chemical reactivity causes changes in chemical composition and structure of the metal/SiC interface. The practical effect of the changes is to alter the electronic and other properties of the device in such a manner as to degrade its performance as a chemical sensor. To delay or prevent these changes, it is necessary to limit operation to a temperature CeO2 films is based partly on the observation that nanostructured materials in general have potentially useful electrical properties, including an ability to enhance the transfer of electrons. In particular, nanostructured CeO2, that is CeO2 with nanosized grains, has shown promise for incorporation into hightemperature electronic devices. Nanostructured CeO2 films can be formed on SiC and have been shown to exhibit high thermal stability on SiC, characterized by the ability to withstand temperatures somewhat greater than 700 C for limited times. The exchanges of oxygen between CeO2 and SiC prevent the formation of carbon and other chemical species that are unfavorable for operation of a SiC-based Schottky diode as a chemical sensor. Consequently, it is anticipated that in a Pd/CeO2/SiC Schottky diode, the nanostructured interfacial CeO2 layer would contribute to

  15. NMR studies on polyphosphide Ce6Ni6P17

    Science.gov (United States)

    Koyama, T.; Yamada, H.; Ueda, K.; Mito, T.; Aoyama, Y.; Nakano, T.; Takeda, N.

    2016-02-01

    We report the result of 31P nuclear magnetic resonance (NMR) studies on Ce6Ni6P17. The observed NMR spectra show a Lorentzian-type and an asymmetric shapes, reflecting the local symmetry around each P site in the cubic unit cell. We have identified the observed NMR lines corresponding to three inequivalent P sites and deduced the temperature dependence of the Knight shift for each site. The Knight shifts increase with decreasing temperature down to 1.5 K, indicating a localized spin system of Ce6Ni6P17. Antiferromagnetic correlation between 4f spins is suggested from the negative sign of the Weiss-temperature.

  16. Lattice anomalies in CeNi unstable valence compound

    Energy Technology Data Exchange (ETDEWEB)

    Lazukov, V.N.; Nefeodova, E.V.; Alekseev, P.A.; Nemkovski, K.S.; Sadikov, I.P.; Tiden, N.N. [RRC ' ' Kurchatov Institute' ' , 123182 Moscow (Russian Federation); Sikolenko, V.V. [JINR, 141980 Dubna, Moscow region (Russian Federation); Staub, U.; Pradervand, C. [SLS, PSI, 5232 Villigen PSI (Switzerland); Braden, M. [LLB, CEA/Saclay, 91191 Gif sur Yvette Cedex (France); INFP Postfach 3640, 76021 Karlsruhe (Germany); Soderholm, L. [Chemistry Division, Argonne National Laboratory, Argonne Il-60439 (United States)

    2002-07-01

    Neutron diffraction and X-ray absorption measurements have been performed to study the changes in the structure and the Ce valence between 10 K and 295 K. No evidence for a phase transition was obtained, but some nearest-neighbour distances have clear peculiarities in the temperature range of 100 K to 150 K. The valence of Ce increases continuously with decreasing temperature, which can explain neither the lattice anomalies nor the previously observed temperature dependence of the phonon frequencies. A correlation between the gap-like magnetic excitation spectrum formed at low temperatures and observed lattice anomalies is discussed. (orig.)

  17. Conductivity and dielectric studies on LiCeO_2

    Institute of Scientific and Technical Information of China (English)

    M.Prabu; S.Selvasekarapandian; A.R.Kulkarni; G.Hirankumar; C.Sanjeeviraja

    2010-01-01

    LiCeO2 was prepared by a solid-state reaction method using microwave heat treatment and identified by X-ray diffractometry.LiCeO2 has monoclinic crystal structure whose conductivity and dielectric properties were studied over a range of frequency(42 Hz to 1 MHz) and temperatures(30-500 °C) using ac technique of complex impedance analyzer HIOKI 3532.Combined impedance and modulus plots were used as tools to analyze the sample behaviour as a function of frequency at different temperatures.The d.c.conductivity...

  18. Baize-like CeO2 and NiO/CeO2 nanorod catalysts prepared by dealloying for CO oxidation

    Science.gov (United States)

    Zhang, Xiaolong; Li, Kun; Shi, Wenyu; Wei, Caihua; Song, Xiaoping; Yang, Sen; Sun, Zhanbo

    2017-01-01

    Baize-like monolithic CeO2 and NiO/CeO2 nanorod catalysts were prepared by combined dealloying and calcination and the catalytic activities were evaluated using CO catalytic oxidation. The CeO2 catalysts were composed of nanorods and exhibited a three-dimensional supporting structure with pores. After introduction of NiO, dispersed NiO nanosheets and nanoparticles were supported on the surface of CeO2 nanorods and they were not well-crystallined due to CeO2 inhibiting the NiO crystallization. The Raman and x-ray photoelectron spectroscopy analyses revealed that the introduction of NiO species into CeO2 generated more coordinate unsaturated Ni atoms, oxygen vacancies, defects and active sites for CO catalytic reactions. The reaction activation energy of NiO/CeO2 nanorod catalyst prepared from the Al83Ce10Ni7 precursor alloy was just 31.2 kJ mol-1 and the CO conversion can reach up to 97% at 240 °C, which was superior to that of pure CeO2 and nanoporous NiO. The enhanced catalytic activity of baize-like NiO/CeO2 nanorods can be attributed to the strong synergistic effects between finely dispersed NiO species and surface oxygen vacancies in CeO2 nanorods.

  19. Adsorption of Ce(Ⅳ) Anionic Nitrato Complexes onto Anion Exchangers and Its Application for Ce(Ⅳ) Separation from Rare Earths(Ⅲ)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Ce(Ⅳ) nitrato complexes were adsorbed on two anion exchangers based on polyvinyl pyridine (PVP) and quaternized PVP incorporated into porous silica matrix. The effect of nitric acid concentration (0.5~6 mol·L-1) and temperature (278~318 K) on Ce(Ⅳ) sorption efficiency was investigated. Sorption increased with increasing nitric acid concentration, indicating that [Ce(NO3)6]2- complex is the main adsorbed Ce(Ⅳ) species. Oxidation of sorbents by adsorbed Ce(Ⅳ) species resulting in Ce(Ⅲ) release to the solution was observed. Pyridine based anion exchangers exhibited higher oxidation stability compared to the commercial strong base anion exchanger. Ce(Ⅳ) reduction was temperature dependent and obeyed pseudo-first-order reaction kinetics. Column separation of Ce(Ⅳ) from La(Ⅲ) and Y(Ⅲ) was carried out from 6 mol·L-1 nitric acid with PVP based anion exchanger. Reasonable Ce(Ⅳ) breakthrough capacity (0.7 mol·kg-1 PVP) was achieved. No remarkable decrease of capacity was observed within 3 consequent runs. In contrast, Ce(Ⅲ) leakage due to reduction decreased and breakthrough capacity slightly increased. This effect was more pronounced with increasing temperature. Regeneration with 0.1 mol·L-1 nitric acid was successful (recovery 100%±4%) and Ce solution of high purity (>99.97%) with respect to La and Y content was gained.

  20. Controlled synthesis of Ce(OH)CO3 flowers by a hydrothermal method and their thermal conversion to CeO2 flowers

    Institute of Scientific and Technical Information of China (English)

    Dongen Zhang; Feng Li; Jian Gu; Qing Xie; Shanzhong Li; Xiaobo Zhang; Guiquan Han; Ailing Ying; Zhiwei Tong

    2012-01-01

    Highly uniform Ce(OH)CO3 flowers were successfully prepared in large quantities using a facile hydrothermal approach from the reaction of Ce(NH4)(NO3)4 with CO(NH2)2 at 160 ℃ in a water-N2H4 complex,The influences of the N2H4 content and temperature on flower formation were discussed.CeO2 flowers were prepared by thermal conversion of Ce(OH)CO3 flowers at 500 ℃ in air.Both Ce(OH)CO3 and CeO2 flowers were characterized by X-ray powder diffraction (XRD),and scanning electron microscopy (SEM),The UV-vis adsorption spectrum of the CeO2 flowers showed that the band gap energy (Eg) is 2.66 eV,which is lower than that of bulk ceria.

  1. Improved sulfur-resistant ability on CO oxidation of Pd/Ce0.75Zr0.25O2 over Pd/CeO2-TiO2 and Pd/CeO2

    Institute of Scientific and Technical Information of China (English)

    沈美庆; 林放; 魏光曦; 王建强; 朱少春

    2015-01-01

    The influence of sulfation on Pd/Ce0.75Zr0.25O2, Pd/CeO2-TiO2 and Pd/CeO2 was investigated. Physical structure and chemical properties of different catalysts were characterized by N2 adsorption, X-ray diffraction (XRD), CO chemisorption, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and X-ray fluorescence (XRF). After 10 h SO2 sulfation, it was found that the decrement on CO oxidation catalytic activity was limited on Pd/Ce0.75Zr0.25O2 compared to Pd/CeO2-TiO2 and Pd/CeO2. It demonstrated that Pd/Ce0.75Zr0.25O2 was more sulfur resistant compared to the other two catalysts. Af-ter sulfur exposure, catalyst texture was not much influenced as shown by N2 adsorption and XRD, and surface Pd atoms were poi-soned indicated by CO chemisorption results. Pd/Ce0.75Zr0.25O2 and Pd/CeO2-TiO2 exhibited less sulfur accumulation compared to Pd/CeO2 in the sulfation process. Furthermore, XPS results clarified that surface sulfur amount, especially surface sulfates amount on the sulfated catalysts was more crucial for the deactivation in sulfur containing environment.

  2. High performance of NO oxidation over Ce-Co-Ti catalyst: The interaction between Ce and Co

    Science.gov (United States)

    Shang, Danhong; Zhong, Qin; Cai, Wei

    2015-01-01

    Ce0.2Co0.2Ti mixed oxide catalyst was synthesized by a facile sol-gel method and the catalytic activity was evaluated through NO oxidation. The catalyst was characterized by XRD, Raman, TEM, H2-TPR, O2-TPD and XPS. The results showed that Ce0.2Co0.2Ti exhibited high catalytic activity of NO oxidation with maximum conversion of 76% at 300 °C under the condition of 400 ppm NO, 8% O2 and 30 000 h-1 GHSV. The high activity was ascribed to the strong interaction between Ce and Co, which resulted in small particle, excellent redox and large amount of chemisorbed oxygen. These features were favorable for the high catalytic performance of NO oxidation.

  3. Fabrication and dye removal performance of magnetic CuFe2O4@CeO2 nanofibers

    Science.gov (United States)

    Zou, Lianli; Wang, Qiuju; Shen, Xiangqian; Wang, Zhou; Jing, Maoxiang; Luo, Zhou

    2015-03-01

    Novel magnetic adsorbents with CeO2 nanoparticles (about 20 nm) coated on CuFe2O4 nanofibers were fabricated by combining electrospinning technique and chemical precipitation methods. The prepared CuFe2O4@CeO2 composite nanofibers show a diameter of 200 nm with a high specific surface area of 64.12 m2/g. These composite nanofibers exhibit a typical soft-magnetic materials behavior with a specific saturation magnetization (Ms) of 20.51 Am2/kg. The adsorption performances of these composite nanofibers were evaluated by column bed studies for methyl orange (MO) removal from aqueous solution. The effect of pH, flow rate and dye concentration on adsorption performances were investigated. The results show that the adsorption capacity decreases with increase of pH. The largest adsorption capacity of the column beds shows about 100 g/mL under the condition of C0 = 0.05 mg/mL, F = 2.0 mL/min and pH 4.0. The kinetic process is described by Thomas model. The rate constant decreases with the extension of reaction time and decreasing pH. The desorption behaviors are also studied in 0.5 M NaCl solution, ethyl alcohol and deionized water, respectively, which show that the adsorbed MO molecules can be easily desorbed from CuFe2O4@CeO2 composite nanofibers in NaCl solution. The adsorption mechanism of ionic interaction, formation of hydrogen bonds and pore diffusion is rationally proposed.

  4. Citrate mediated synthesis of uniform monazite LnPO4 (Ln = La, Ce) and Ln:LaPO4 (Ln = Eu, Ce, Ce + Tb) spheres and their photoluminescence.

    Science.gov (United States)

    Nuñez, Nuria O; Liviano, Sonia R; Ocaña, Manuel

    2010-09-15

    A simple method for the synthesis of spherical LaPO(4) (monazite) particles with narrow size distribution and tailored size in the 150-500 nm range is reported. The procedure is based on a homogeneous precipitation process at low temperature (120 degrees C) from solutions containing La(3+), citrate and phosphate ions under a very restrictive set of experimental conditions, which involves the use of La nitrate, citric acid and phosphoric acid as precursors and ethylene glycol as solvent. The growth mechanism of the spheres was investigated aiming at explaining the differences in particle size and shape observed when varying the experimental conditions. The applicability of this method for the synthesis of spherical particles of other lanthanide (Ce, Tb, Eu) phosphates is also analyzed. Finally, it is shown that the developed procedure can be used to dope the lanthanum phosphate particles with lanthanide cations, which resulted in spherical phosphors as illustrated for the Eu-doped, Ce-doped and Ce, Tb codoped systems, whose luminescent properties are also evaluated.

  5. Structural characterization of nanosized CeO(2)-SiO(2), CeO(2)-TiO(2), and CeO(2)-ZrO(2) catalysts by XRD, Raman, and HREM techniques.

    Science.gov (United States)

    Reddy, Benjaram M; Khan, Ataullah; Lakshmanan, Pandian; Aouine, Mimoun; Loridant, Stéphane; Volta, Jean-Claude

    2005-03-03

    Structural characteristics of nanosized ceria-silica, ceria-titania, and ceria-zirconia mixed oxide catalysts have been investigated using X-ray diffraction (XRD), Raman spectroscopy, BET surface area, thermogravimetry, and high-resolution transmission electron microscopy (HREM). The effect of support oxides on the crystal modification of ceria cubic lattice was mainly focused. The investigated oxides were obtained by soft chemical routes with ultrahighly dilute solutions and were subjected to thermal treatments from 773 to 1073 K. The XRD results suggest that the CeO(2)-SiO(2) sample primarily consists of nanocrystalline CeO(2) on the amorphous SiO(2) surface. Both crystalline CeO(2) and TiO(2) anatase phases were noted in the case of CeO(2)-TiO(2) sample. Formation of cubic Ce(0.75)Zr(0.25)O(2) and Ce(0.6)Zr(0.4)O(2) (at 1073 K) were observed in the case of the CeO(2)-ZrO(2) sample. Raman measurements disclose the fluorite structure of ceria and the presence of oxygen vacancies/Ce(3+). The HREM results reveal well-dispersed CeO(2) nanocrystals over the amorphous SiO(2) matrix in the cases of CeO(2)-SiO(2), isolated CeO(2), and TiO(2) (anatase) nanocrystals, some overlapping regions in the case of CeO(2)-TiO(2), and nanosized CeO(2) and Ce-Zr oxides in the case of CeO(2)-ZrO(2) sample. The exact structural features of these crystals as determined by digital diffraction analysis of HREM experimental images reveal that the CeO(2) is mainly in cubic fluorite geometry. The oxygen storage capacity (OSC) as determined by thermogravimetry reveals that the OSC of the mixed oxide systems is more than that of pure CeO(2) and is system dependent.

  6. Phase Equilibria of the Ce-Mg-Zn Ternary System at 300 °C

    Directory of Open Access Journals (Sweden)

    Ahmad Mostafa

    2014-05-01

    Full Text Available The isothermal section of the Ce-Mg-Zn system at 300 °C was experimentally established in the full composition range via diffusion multiple/couples and key alloys. Annealed key alloys were used to confirm the phase equilibria obtained by diffusion multiple/couples and to determine the solid solubility ranges. Spot analysis was carried out, using wavelength dispersive X-ray spectroscopy (WDS, to identify the composition of the observed phases. The composition profiles were obtained using WDS line-scans across the diffusion zones. X-ray diffraction (XRD was performed to identify the phases in the annealed alloys and to confirm the WDS results. Eight ternary compounds, in the Ce-Mg-Zn isothermal section at 300 °C, were observed from 45–80 at.% Zn. These are: τ1 (Ce6Mg3Zn19, τ2 (CeMg29Zn25, τ3 (Ce2Mg3Zn3, τ4 (CeMg3Zn5, τ5 (CeMg7Zn12, τ6 (CeMg2.3−xZn12.8+x; 0 ≤ x ≤ 1.1, τ7 (CeMgZn4 and τ8 (Ce(Mg1−yZny11; 0.096 ≤ y ≤ 0.43. The ternary solubility of Zn in the Ce-Mg compounds was found to increase with a decrease in Mg concentration. Accordingly, the ternary solid solubility of Zn in CeMg12 and CeMg3 was measured as 5.6 and 28.4 at.% Zn, respectively. Furthermore, the CeMg and CeZn showed a complete solid solubility. The complete solubility was confirmed by a diffusion couple made from alloys containing CeMg and CeZn compounds.

  7. Electrochemical formation process and phase control of Mg-Li-Ce alloys in molten chlorides

    Institute of Scientific and Technical Information of China (English)

    ZHANG Meng; HAN Wei; ZHANG Milin; ZHU Fengyan; XUE Yun; ZHANG Zhijian

    2013-01-01

    An electrochemical approach for the preparation of Mg-Li-Ce alloys by co-reduction of Mg,Li and Ce on a molybdenum electrode in KCl-LiCl-MgCl2-CeCl3 melts at 873 K was investigated.Cyclic voltammograms (CVs) and square wave voltammograms indicated that the underpotential deposition (UPD) of cerium on pre-deposited magnesium led to the formation of Mg-Ce alloys at electrode potentials around-1.87 V.The order of electrode reactions was as follows:discharge of Mg(Ⅱ) to Mg-metal,UPD of Ce on the surface of pre-deposited Mg with formation of Mg-Ce alloys,discharge of Ce(Ⅲ) to Ce-metal and after that the discharge of Li+ with the deposition of Mg-Li-Ce alloys,which was investigated by CVs,chronoamperometry,chronopotentiometry and open circuit chronopotentiometry.X-ray diffraction (XRD) illuminated that Mg-Li-Ce alloys with different phases were obtained via galvanostatic electrolysis by different current densities.The microstructures of Mg-Li-Ce alloys were characterized by optical microscopy (OM) and scanning electron microscopy (SEM),respectively.The analysis of energy dispersive spectrometry (EDS) showed that Ce existed at grain boundaries to restrain the grain growth.The compositions and the average grain sizes of Mg-Li-Ce alloys could be obtained controllably corresponding with the phase structures of the XRD patterns.

  8. Estimation of bulk transfer coefficient for latent heat flux (Ce)

    Digital Repository Service at National Institute of Oceanography (India)

    Sadhuram, Y.

    specific humidity at sea surface tempera- ture, qn is the specific humidity at deck level, and U is the wind speed at the height of anemometer. All the available data in each area and along the boundaries are used to compute E. NFD and Ce. 3. Results...

  9. Solid Electrolyte Based on Perovskite-type BaCeO3 and SrCeO3%BaCeO3和SrCeO3基钙钛矿型固体电解质

    Institute of Scientific and Technical Information of China (English)

    张俊英; 张中太

    2000-01-01

    综述了BaCeO3基和SrCeO3基钙钛矿型固体电解质.从结构、不同气氛中导电性方面进行了介绍,对其应用方面进行了较为详细的分析.在燃料电池、电解池、薄膜反应器、气体传感器等方面的应用分析表明这2类固体电解质有广泛的应用前景.%Solid electrolyte based on perovskite-type BaCeO3 and SrCeO3 was reviewed .Microstructure and conductivity in different atmosphere were introduced while application was analyzed in detail. Applications in fuel cell, steam electrolysis cell, membrane reactor, gas sensor indicate that these kinds of solid electrolytes may be prospective materials that can be used in many fields.

  10. Itinerant magnetism in CeRh3B2

    DEFF Research Database (Denmark)

    Eriksson, Olle; Johansson, Börje; Brooks, M. S. S.

    1989-01-01

    Spin-polarized energy-band calculations, including spin-orbit coupling in the band Hamiltonian, have been performed on CeRh3B2. Good agreement is obtained between theory and experiment concerning the magnetic moment. It is also found that the magnetic moment varies strongly with volume and from...

  11. CE microchips: an opened gate to food analysis.

    Science.gov (United States)

    Escarpa, Alberto; González, María Cristina; Crevillén, Agustín González; Blasco, Antonio Javier

    2007-03-01

    CE microchips are the first generation of micrototal analysis systems (-TAS) emerging in the miniaturization scene of food analysis. CE microchips for food analysis are fabricated in both glass and polymer materials, such as PDMS and poly(methyl methacrylate) (PMMA), and use simple layouts of simple and double T crosses. Nowadays, the detection route preferred is electrochemical in both, amperometry and conductivity modes, using end-channel and contactless configurations, respectively. Food applications using CE microchips are now emerging since food samples present complex matrices, the selectivity being a very important challenge because the total integration of analytical steps into microchip format is very difficult. As a consequence, the first contributions that have recently appeared in the relevant literature are based primarily on fast separations of analytes of high food significance. These protocols are combined with different strategies to achieve selectivity using a suitable nonextensive sample preparation and/or strategically choosing detection routes. Polyphenolic compounds, amino acids, preservatives, and organic and inorganic ions have been studied using CE microchips. Thus, new and exciting future expectations arise in the domain of food analysis. However, several drawbacks could easily be found and assumed within the miniaturization map.

  12. A Sesame Equation of State for Dense Ce

    Energy Technology Data Exchange (ETDEWEB)

    Greeff, Carl William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Crockett, Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-15

    We generated a new Sesame equation of state table for Ce. It is a single effective phase table for the high density phases α, α ', ϵ and liquid. Also, the EOS is meant to be used with a ramp to represent the initial low density γ phase.

  13. Commensurate-commensurate magnetic phase transitions in CeSb

    DEFF Research Database (Denmark)

    Lebech, Bente; Broholm, C.; Clausen, K.;

    1986-01-01

    The q=2/3 to q=4/7 commensurate-commensurate phase transition in CeSb has been studied by neutron diffraction. On cooling the commensurate wave vector q changes abruptly from 2/3 to a higher-order commensurate value (≈14/23) at T1

  14. Improved performance of QCD code on ALiCE

    CERN Document Server

    Sroczynski, Z

    2003-01-01

    We present results for the performance of QCD code on ALiCE, the Alpha-Linux Cluster Engine at Wuppertal. We describe the techniques employed to optimise the code, including the metaprogramming of assembler kernels, the effects of data layout and an investigation into the overheads incurred by the communication.

  15. Improved performance of QCD code on ALiCE

    Science.gov (United States)

    Sroczynski, Z.

    2003-05-01

    We present results for the performance of QCD code on ALiCE , the Alpha-Linux Cluster Engine at Wuppertal. We describe the techniques employed to optimise the code, including the metaprogramming of assembler kernels, the effects of data layout and an investigation into the overheads incurred by the communication.

  16. Ce-Y-O固溶体及其PdO/Ce-Y-O催化剂的制备,表征和CH4氧化性能%Characterization and Preparation of Ce-Y-O Solid Solutions and PdO/Ce-Y-O Catalysts for CH4 Oxidation

    Institute of Scientific and Technical Information of China (English)

    罗孟飞; 单文娟; 李美俊; 鲁继青; 李灿

    2001-01-01

    Ce-Y-O Solid Solution was prepared by citrate sol-gel method,and characterized by using XRD,Raman and TPR techniques.The structure of the solid solution depends on the Ce/(Ce+Y)ratio.When Ce/(Ce+Y)≥0.6,only face centered cubic phase is observed.When Ce/(Ce+Y)≤0.5,only body centered cubic phase is observed.The addition of Y atoms into CeO2 improves the reduction-oxidation behavior.Ce-Y-O-supported PdO catalysts show higher activity for CH4 oxidation than PdO/CeO2 and PdO/Y2O3 catalysts.The PdO/Ce0.8Y0.2O1.90 catalyst is the most active of all catalysts.%采用柠檬酸溶胶-凝胶法制备了Ce-Y-O固溶体,并用XRD和Raman对Ce-Y-O固溶体的物相结构进行了表征,发现当n(Ce)/n(Ce+Y)(摩尔比)≥0.6时,Ce-Y-O固溶体为面心立方结构,而n(Ce)/n(Ce+Y)≤0.5时为体心立方结构。固溶体的生成有利于提高氧化还原性能。Ce-Y-O固溶体担载PdO催化剂的CH4氧化活性表明,n(Ce)/n(Ce+Y)对担载PdO催化剂的CH4氧化活性影响很大,当n(Ce)/n(Ce+Y)=0.8时催化剂活性最高,CH4转化率50%的温度为350℃,完全转化温度为600℃。

  17. The effect of precursors salts on surface state of Pd/Al2O3 and Pd/CeO2/Al2O3 catalysts

    Directory of Open Access Journals (Sweden)

    André L. Guimarães

    2004-12-01

    Full Text Available The influence of the precursors on the promoting effect of ceria on Pd/Al2O3 catalyst, when ceria is coated over alumina was studied. The reaction of propane oxidation proceeded under different feed conditions and the surface active sites were characterized by X-ray photoelectron spectroscopy (XPS and in situ diffuse reflectance spectroscopy (DRS. XPS and DRS results show that PdO/Pd0 interface are the active sites independent of the precursor, while the catalysts containing CeO2 showed formation of palladium species in the highest oxidation state, probably PdO2 (338 eV after the oxidation of propane. Besides, the O/Al and O/Ce ratios evidenced the increase of oxygen storage in the presence of CeO2. In addition, the precursor acetylacetonate favors the oxygen storage in the lattice.Estudo da influência dos precursores sobre os catalisadores de Pd/Al2O3 promovidos com céria ancorado sobre a alumina. A oxidação do propano foi feita sob diferentes condições de alimentação sendo caracterizados os sítios superficiais por Espectroscopia Fotoeletrônica de raios X (XPS e por Refletância Difusa em ''situ''. Resultados de XPS e DRS mostraram a formação de interfaces de PdO/Pd0 como sendo os sítios ativos, independentes do precursor utilizado na preparação, enquanto que os catalisadores contendo CeO2 mostraram a formação de espécies de paládio com estado de oxidação mais altos, provavelmente PdO2 (338 eV após a oxidação do propano. Além disso, as razões O/Al e O/Ce evidenciaram um aumento de oxigênio armazenado na presença de CeO2. O precursor acetilacetonato favoreceu o armazenamento de oxigênio na rede.

  18. Cério (Ce em ferricretes nodulares desenvolvidos em solos da formação adamantina Cerium (Ce in some nodular ferricretes developed in soils of the adamantina formation

    Directory of Open Access Journals (Sweden)

    Maurício Rizzato Coelho

    2000-06-01

    Full Text Available O estudo de concentrações anômalas de elementos traço em ferricretes, como cério (Ce e outros elementos das terras raras, tem apoiado discussões a respeito da gênese dessas feições em diferentes ambientes do planeta. No município de Pindorama (SP, no sopé de uma vertente com domínio de Argissolos Vermelho-Amarelos abrúpticos derivados do arenito cretácico da Formação Adamantina, Grupo Bauru (Ka, ocorrem horizontes ferricretes, cujas características e gênese são escassamente conhecidas, embora sejam de ocorrência comum na região norte do Estado de São Paulo. Procurou-se verificar a presença de concentrações de elementos terras raras nesses solos e assim poder fornecer subsídios para o conhecimento da gênese desses ferricretes, estudando-se um Argissolo Vermelho-Amarelo Eutrófico abrúptico plíntico dessa vertente. Após descrição morfológica do perfil, determinou-se a granulometria, bem como as concentrações de Fe e Mn totais (fluorescência de raios X, extraídos por ataque sulfúrico, ditionito-citrato e por oxalato dos horizontes e dos nódulos encontrados. Em glébulas selecionadas, realizou-se estudos submicroscópicos e microanálises pontuais. Acumulações localizadas de Ce na forma de cerianita (CeO2 foram encontradas apenas nos nódulos petroplínticos que apresentam revestimentos de óxidos de Mn, situados na base do horizonte petroplíntico, e cuja gênese está associada ao rebaixamento definitivo do lençol freático. Cobalto (Co também se concentra no interior dos nódulos ferro-manganíferos devido à ação co-precipitadora dos óxidos de manganês aí depositados.The observation of rare earth element (REE accumulations, especially Ce, has led to an open discussion about the genesis of lateritic weathering systems. In the landscape of the northern State of São Paulo (Brazil, lateritic covers predominantly nodular exist in different topographic levels and, although not documented, constitute a

  19. Synthesis and electrochemical properties of Ce-doped LiNi1/3Mn1/3C01/3O2 cathode material for Li-ion batteries

    Institute of Scientific and Technical Information of China (English)

    ZHONG Shengkui; WANG You; LIU Jiequn; WAN Kang; L(U) Fan

    2011-01-01

    The layered material of Ce-doped LiNi1/3Mn1/3Co1/3O2 with α-NaFeO2 was synthesized by a co-precipitation method.X-ray diffraction (XRD) showed that Ce-doped LiNi1/3Mn1/3Co1/3O2 had the same layered structure as the undoped LiNi1/3Mn1/3Co1/3O2.The scanning electron microscopy (SEM) images exhibited that the particle size of Ce-doped LiNi1/3Mn1/3Co1/3O2 was smaller than that of the undoped LiNi1/3Mn1/3Co1/3O2.The Ce-doped LiNi1/3Mn1/3Co1/3O2 samples were investigated on the Li extraction/insertion performances through charge/discharge,cyclic voltammogram (CV),and electrochemical impedance spectra (EIS).The optimal doping content of Ce was x=0.02 in the LiNi1/3-xMn1/3Co1/3CexO2 samples to achieve high discharge capacity and good cyclic stability.The electrode reaction reversibility was enhanced,and the charge transfer resistance was decreased through Ce-doping.The improved electrochemical performances of the Ce-doped LiNi1/3Mn1/3Co1/3O2 cathode materials were attributed to the addition ofCe4+ ion by stabilizing the layer structure.

  20. Evolution of magnetism from mixed-valent CeIr3B2 to trivalent CeIr3Si2

    Science.gov (United States)

    Umarji, A. M.; Dhar, S. K.; Malik, S. K.; Vijayaraghavan, R.

    1987-12-01

    The ternary compound CeIr3B2 is a mixed-valent material crystallizing in a monoclinic structure, closely related to the hexagonal CeCo3B2-type structure. The structural and magnetic phase diagrams of the systems CeRh3-yIryB2 (y=0-2) and CeIr3B2-xSix (x=0-2) have been investigated. Properties of the new compound CeIr3Si2 have been reported for the first time. It is shown that the structure of CeIr3B2 transforms to the hexagonal type on substitution of Rh and Si at Ir and B sites, respectively. Accompanying the structural transformation is an electronic transition in which the mixed-valent Ce atoms become more magnetic. The observed ferromagnetic ground state is similar to the one seen in CeRh3B2 (TC=115 K and μsat=0.4μB). The role of Ce-atom ligands and their hybridization is thought to be the primary cause for the unusual nature magnetism in CeT3B2-type compounds.

  1. Luminescence properties of Gd2Si2O7:Ce and Gd2Si2O7:La,Ce under vacuum ultraviolet irradiation

    Institute of Scientific and Technical Information of China (English)

    M Koshimizu; T Yanagida; Y Fujimoto; K Asai

    2016-01-01

    The luminescence properties of Ce-or Ce and La-doped gadolinium pyrosilicate (Gd2Si2O7, GPS) were characterized using vacuum ultraviolet (VUV) excitation light. A prominent emission band was observed in the luminescence spectra with excitation at 60 nm and ascribed to 5d-4f transition of Ce3+. Because the excitation wavelength of 60 nm corresponded to the excitation in the host matrix, this result indicated that the excitation energy transfer occurred from the host matrix to Ce3+ions. On the basis of the rise in the luminescence time profiles with excitation at 60 nm, the energy transfer occurred within 2 ns, which was much shorter than that of Ce-doped Gd2SiO5. For Ce-doped GPS, the decay rate was slower for the host excitation than that for direct excitation of Ce3+. In contrast, for Ce and La-doped GPS, no significant difference was observed for the host excitation and direct excitation of Ce3+. This result indicated that the energy transfer from the host to Ce3+ions led to a different radiative decay process, and that La doping had an effect on the energy transfer and decay process.

  2. Ce3+-ion-induced visible-light photocatalytic degradation and electrochemical activity of ZnO/CeO2 nanocomposite

    Science.gov (United States)

    Rajendran, Saravanan; Khan, Mohammad Mansoob; Gracia, F.; Qin, Jiaqian; Gupta, Vinod Kumar; Arumainathan, Stephen

    2016-08-01

    In this study, pure ZnO, CeO2 and ZnO/CeO2 nanocomposites were synthesized using a thermal decomposition method and subsequently characterized using different standard techniques. High-resolution X-ray photoelectron spectroscopy measurements confirmed the oxidation states and presence of Zn2+, Ce4+, Ce3+ and different bonded oxygen species in the nanocomposites. The prepared pure ZnO and CeO2 as well as the ZnO/CeO2 nanocomposites with various proportions of ZnO and CeO2 were tested for photocatalytic degradation of methyl orange, methylene blue and phenol under visible-light irradiation. The optimized and highly efficient ZnO/CeO2 (90:10) nanocomposite exhibited enhanced photocatalytic degradation performance for the degradation of methyl orange, methylene blue, and phenol as well as industrial textile effluent compared to ZnO, CeO2 and the other investigated nanocomposites. Moreover, the recycling results demonstrate that the ZnO/CeO2 (90:10) nanocomposite exhibited good stability and long-term durability. Furthermore, the prepared ZnO/CeO2 nanocomposites were used for the electrochemical detection of uric acid and ascorbic acid. The ZnO/CeO2 (90:10) nanocomposite also demonstrated the best detection, sensitivity and performance among the investigated materials in this application. These findings suggest that the synthesized ZnO/CeO2 (90:10) nanocomposite could be effectively used in various applications.

  3. Ce(3+)-ion-induced visible-light photocatalytic degradation and electrochemical activity of ZnO/CeO2 nanocomposite.

    Science.gov (United States)

    Rajendran, Saravanan; Khan, Mohammad Mansoob; Gracia, F; Qin, Jiaqian; Gupta, Vinod Kumar; Arumainathan, Stephen

    2016-08-16

    In this study, pure ZnO, CeO2 and ZnO/CeO2 nanocomposites were synthesized using a thermal decomposition method and subsequently characterized using different standard techniques. High-resolution X-ray photoelectron spectroscopy measurements confirmed the oxidation states and presence of Zn(2+), Ce(4+), Ce(3+) and different bonded oxygen species in the nanocomposites. The prepared pure ZnO and CeO2 as well as the ZnO/CeO2 nanocomposites with various proportions of ZnO and CeO2 were tested for photocatalytic degradation of methyl orange, methylene blue and phenol under visible-light irradiation. The optimized and highly efficient ZnO/CeO2 (90:10) nanocomposite exhibited enhanced photocatalytic degradation performance for the degradation of methyl orange, methylene blue, and phenol as well as industrial textile effluent compared to ZnO, CeO2 and the other investigated nanocomposites. Moreover, the recycling results demonstrate that the ZnO/CeO2 (90:10) nanocomposite exhibited good stability and long-term durability. Furthermore, the prepared ZnO/CeO2 nanocomposites were used for the electrochemical detection of uric acid and ascorbic acid. The ZnO/CeO2 (90:10) nanocomposite also demonstrated the best detection, sensitivity and performance among the investigated materials in this application. These findings suggest that the synthesized ZnO/CeO2 (90:10) nanocomposite could be effectively used in various applications.

  4. Ce-Fe-modified zeolite-rich tuff to remove Ba(2+)-like (226)Ra(2+) in presence of As(V) and F(-) from aqueous media as pollutants of drinking water.

    Science.gov (United States)

    Olguín, María Teresa; Deng, Shuguang

    2016-01-25

    The sorption behavior of the Ba(2+)-like (226)Ra(2+) in the presence of H2AsO4(-)/HAsO4(2-) and F(-) from aqueous media using Ce-Fe-modified zeolite-rich tuff was investigated in this work. The Na-modified zeolite-rich tuff was also considered for comparison purposes. The zeolite-rich tuff collected from Wyoming (US) was in contact with NaCl and CeCl3-FeCl3 solutions to obtain the Na- and Ce-Fe-modified zeolite-rich tuffs (ZUSNa and ZUSCeFe). These zeolites were characterized by scanning electron microscopy and X-ray diffraction. The BET-specific surface and the points of zero charge were determined as well as the content of Na, Ce and Fe by neutron activation analysis. The textural characteristics and the point of zero charge were changed by the presence of Ce and Fe species in the zeolitic network. A linear model described the Ba(2+)-like (226)Ra(2+) sorption isotherms and the distribution coefficients (Kd) varied with respect to the metallic species present in the zeolitic material. The As(V) oxianionic chemical species and F(-) affected this parameter when the Ba(2+)-like (226)Ra(2+)-As(V)-F(-) solutions were in contact with ZUSCeFe. The H2AsO4(-)/HAsO4(2-) and F(-) were adsorbed by ZUSCeFe in the same amount, independent of the concentration of Ba(2+)-like (226)Ra(2+) in the initial solution.

  5. Preparation with laser ablation and photoluminescence of Y3Al5O12:Ce nanophosphors

    Science.gov (United States)

    Cho, Young-Sik; Huh, Young-Duk; Park, Chan Ryang; Do, Young Rag

    2014-03-01

    We prepared Y3Al5O12:Ce (YAG:Ce) nanophosphors with a mean size of 15 nm by using laser ablation of micron-sized commercial YAG:Ce target phosphor in 1,4-butanediol. The photoluminescence properties of the YAG:Ce nanophosphors were compared with those of micron-sized YAG:Ce phosphor. The elimination of back-scattering effect was confirmed by the optical properties of the YAG:Ce nanophosphors. The thermal stability of the YAG:Ce nanophosphors was also examined for the use of high power white LED. We convinced that the laser ablation method in 1,4-butanediol is an adequate method for the preparation of YAG:Ce nanophosphors for high power white LED with enhancement of the transmittance of the blue light from the InGaN chip.

  6. A novel sensitive sheathless CE-MS device for peptide and protein analysis

    DEFF Research Database (Denmark)

    Nguyen, Tam T. T. N.; Petersen, Nickolaj J.; Rand, Kasper Dyrberg

    Introduction CE-MS has shown considerable potential in protein research and pharmaceutical development, however, technical challenges of hyphenation of CE with MS have limited its use. Here, we have developed a sensitive CE-MS setup for peptide and protein analysis, that employs a novel and low......-cost sheathless CE-MS interface and a poly(ethyleneglycol)-coated capillary. Using the CE-MS setup, we have achieved fast and efficient separation and sensitive mass analysis of individual components of a complex sample of pharmaceutically relevant human proteins including insulin, tissue factor, α......-synuclein and a tryptic digest of bovine serum albumin. We have furthermore compared the performance of the CE-MS technique to UPLC-MS and demonstrate significant advantages of the CE-MS setup in terms of analysis time, sample consumption and separation capacity. Methods The sheathless CE-MS interface is based...

  7. The equiatomic intermetallics REPtCd (RE = La, Ce, Pr, Nd, Eu) and magnetic properties of CeAuCd

    Energy Technology Data Exchange (ETDEWEB)

    Johnscher, Michael; Niehaus, Oliver; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Tappe, Frank [Hochschule Hamm-Lippstadt, Hamm (Germany)

    2015-06-01

    The cadmium intermetallics REPtCd (RE = La, Ce, Pr, Nd, Eu) and CeAuCd were synthesized by induction-melting of the elements in sealed niobium ampoules followed by annealing in muffle furnaces. The samples were characterized by powder X-ray diffraction. The structures of CePtCd (ZrNiAl type, P anti 62m, a = 763.8(6), c = 409.1(4) pm, wR2 = 0.0195, 298 F{sup 2} values, 14 variables) and EuPtCd (TiNiSi type, Pnma, a = 741.3(2), b = 436.4(1), c = 858.0(4) pm, wR2 = 0.0385, 440 F{sup 2} values, 20 variables) were refined from single-crystal data. The REPtCd structures exhibit three-dimensional networks of corner- and edge-sharing Cd rate at Pt{sub 2/6}Pt{sub 2/3} and Cd rate at Pt{sub 4/4} tetrahedra, which leave cages for the rare earth atoms. Temperature-dependent magnetic susceptibility data of CeAuCd reveal a paramagnetic to antiferromagnetic phase transition at T{sub N} = 3.7(5) K.

  8. Preparation and Characterization of CeO2/YSZ/CeO2 Buffer Layers for YBCO Coated Conductors

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    CeO2 seed layer was deposited on rolling-assisted biaxially textured metal substrates by direct-current (DC) magnetron reactive sputtering. The effect of deposition temperature on epitaxial orientation of CeO2 thin films was examined. High quality CeO2 layers were achieved at deposition temperature from 750℃ to 850℃.Subsequently yttria-stabilized zirconia (YSZ) and CeO2 films were deposited to complete the buffer layer structure via the same process. The best samples exhibited a highly biaxial texture, as indicated by FWHM (full width half maximum) values in the range of 4°-5°, and 2°-4° for in-plane and out-of-plane orientations,respectively. Secondary ion mass spectrometer analysis confirmed the effective prevention of buffer layer against Ni and W metal interdiffusion. Atomic force microscope observations revealed a smooth, dense and crack-free surface morphology, which provided themselves as the good buffer structure to the YBa2Cu3O7-δ(YBCO) coated conductors.

  9. Dehybridization of the 4f shell in Si-substituted CeRh3B2

    Science.gov (United States)

    Malik, S. K.; Shenoy, G. K.; Dhar, S. K.; Paulose, P. L.; Vijayaraghavan, R.

    1986-12-01

    The compound CeRh3B2 is known to order magnetically with an unusually high Curie temperature (TC) of 115 K and a low saturation moment of about 0.4μB. We have studied the magnetic behavior of the system CeRh3(B1-xSix)2 (0CeRh3B2 arises because of the Ce 4f hybridization with the neighboring ligands.

  10. Influence of mineralizer agents on the growth of crystalline CeO{sub 2} nanospheres by the microwave-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Deus, R.C. [Universidade Estadual Paulista-Unesp - Faculdade de Engenharia de Guaratingueta, Av. Dr. Ariberto Pereira da Cunha, 333 Bairro Portal das Colinas, CEP 12516-410 Guaratingueta-SP (Brazil); Cilense, M.; Foschini, C.R. [Universidade Estadual Paulista-Unesp - Instituto de Quimica - Laboratorio Interdisciplinar em Ceramica (LIEC), Rua Professor Francisco Degni s/n, CEP 14800-90 Araraquara, SP (Brazil); Ramirez, M.A. [Universidade Estadual Paulista-Unesp - Faculdade de Engenharia de Guaratingueta, Av. Dr. Ariberto Pereira da Cunha, 333 Bairro Portal das Colinas, CEP 12516-410 Guaratingueta-SP (Brazil); Longo, E. [Universidade Estadual Paulista-Unesp - Instituto de Quimica - Laboratorio Interdisciplinar em Ceramica (LIEC), Rua Professor Francisco Degni s/n, CEP 14800-90 Araraquara, SP (Brazil); Simoes, A.Z., E-mail: alezipo@yahoo.com [Universidade Estadual Paulista-Unesp - Faculdade de Engenharia de Guaratingueta, Av. Dr. Ariberto Pereira da Cunha, 333 Bairro Portal das Colinas, CEP 12516-410 Guaratingueta-SP (Brazil); Universidade Federal de Itajuba-Unifei - Campus Itabira, Rua Sao Paulo, 377 Bairro Amazonas, CEP 35900-37 Itabira, MG (Brazil)

    2013-02-15

    Cystalline ceria (CeO{sub 2}) nanoparticles have been synthesized by a simple and fast microwave-assisted hydrothermal (MAH) under NaOH, KOH, and NH{sub 4}OH mineralizers added to a cerium ammonium nitrate aqueous solution. The products were characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transformed-IR and Raman spectroscopies. Rietveld refinement reveals a cubic structure with a space group Fm3m while infrared data showed few traces of nitrates. Field emission scanning microcopy (FEG-SEM) revealed a homogeneous size distribution of nanometric CeO{sub 2} nanoparticles. The MAH process in KOH and NaOH showed most effective to dehydrate the adsorbed water and decrease the hydrogen bonding effect leaving a weakly agglomerated powder of hydrated ceria. TEM micrographs of CeO{sub 2} synthesized under MAH conditions reveal particles well-dispersed and homogeneously distributed. The MAH enabled cerium oxide to be synthesized at 100 Degree-Sign C for 8 min.

  11. 谷壳制备的白炭黑研制Ce-MEL分子筛及其吸附性能的研究%STUDY ON THE SYNTHESIS AND PROPERTIES OF Ce-MEL ZEOLITE USING WHITE CARBON BLACK FROM HULL

    Institute of Scientific and Technical Information of China (English)

    南小英; 成岳; 潘顺龙; 李杰文

    2012-01-01

    The experimental research on white carbon black which was prepared with husk for silicon source,HMI for organic templates,under the molar ratio of 0.05Na2O∶SiO2∶0.35TBAOH∶40H2O∶(0.001-0.1)Ce(NO)3·6H2O prepared Ce-MEL molecular sieve by the method of static hydrothermal synthesis crystallization and obtained the superficial characteristics of molecular sieve with XRD,SEM etc.The results showed that Ce-MEL molecular sieve superficial characteristics was better,the decolorization rate when the experiment conditions were Ce-MEL dosage of 2.5g / L,pH 7,the oscillation time of 120 min is 88.5%.%以谷壳制备的白炭黑为硅源、四丁基溴化铵(TBAOH)为模板剂,按0.05Na2O∶SiO2∶0.35TBAOH∶40H2O∶(0.001-0.1)Ce(NO)3.6H20的摩尔比,170℃下水热晶化48h合成了Ce-MEL分子筛,并采用XRD、SEM等手段对合成分子筛进行表征。吸附性能结果表明,Ce-MEL分子筛的投加量为2.5g/L、pH为7、振荡时间为2h时吸附效果较好,脱色率达到88.5%。

  12. In-situ electrochemical route to aerogel electrode materials of graphene and hexagonal CeO₂.

    Science.gov (United States)

    Chen, Kunfeng; Xue, Dongfeng

    2015-05-15

    We reported a one-step in-situ electrochemical route to synthesize 3D aerogel electrode materials including graphene and hexagonal CeO2 composites. The graphene/CeO2 aerogel can be formed via freeze-drying graphene/CeO2 colloidal solution that was obtained by electrochemical exfoliation of graphite anode and in-situ deposition of CeO2 nanoparticles on graphene sheets in mixing electrolyte of (NH4)2SO4/Ce(NO3)3 and (NH4)2SO4/(NH4)2Ce(NO3)6. The as-obtained CeO2 nanoparticles were closely contacted with graphene, which can enhance the synergistic effect between graphene and CeO2. It is interesting that the as-obtained CeO2 products possessed hexagonal crystal structure that was rarely reported. The Faradaic reactivity of the graphene/CeO2 composites as supercapacitor was enhanced with the increase of the concentration of Ce salts in initial electrolyte. The introduction of CeO2 to graphene electrode can lead to the presence of additional pseudocapacitance besides the electric double-layer capacitance. This simple one-step in-situ electrochemical route can be extended to synthesize various graphene/metal oxide aerogel electrode materials for electric energy storage.

  13. Redox enzyme-mimicking activities of CeO2 nanostructures: Intrinsic influence of exposed facets

    Science.gov (United States)

    Yang, Yushi; Mao, Zhou; Huang, Wenjie; Liu, Lihua; Li, Junli; Li, Jialiang; Wu, Qingzhi

    2016-10-01

    CeO2 nanoparticles (NPs) have been well demonstrated as an antioxidant in protecting against oxidative stress-induced cellular damages and a potential therapeutic agent for various diseases thanks to their redox enzyme-mimicking activities. The Ce3+/Ce4+ ratio and oxygen vacancies on the surface have been considered as the major originations responsible for the redox enzyme-mimicking activities of CeO2 NPs. Herein, CeO2 nanostructures (nanocubes and nanorods) exposed different facets were synthesized via a facile hydrothermal method. The characterizations by X-ray photoelectron spectroscopy, Raman spectroscopy, and UV-Vis spectroscopy show that the Ce3+/Ce4+ ratio and oxygen vacancy content on the surfaces of as-synthesized CeO2 nanostructures are nearly at the same levels. Meanwhile, the enzymatic activity measurements indicate that the redox enzyme-mimicking activities of as-synthesized CeO2 nanostructures are greatly dependent on their exposed facets. CeO2 nanocubes with exposed {100} facets exhibit a higher peroxidase but lower superoxide dismutase activity than those of the CeO2 nanorods with exposed {110} facets. Our results provide new insights into the redox enzyme-mimicking activities of CeO2 nanostructures, as well as the design and synthesis of inorganic nanomaterials-based artificial enzymes.

  14. Photocatalytic degradation of methyl orange by CeO2 and Fe-doped CeO2 films under visible light irradiation.

    Science.gov (United States)

    Channei, D; Inceesungvorn, B; Wetchakun, N; Ukritnukun, S; Nattestad, A; Chen, J; Phanichphant, S

    2014-08-29

    Undoped CeO2 and 0.50-5.00 mol% Fe-doped CeO2 nanoparticles were prepared by a homogeneous precipitation combined with homogeneous/impreganation method, and applied as photocatalyst films prepared by a doctor blade technique. The superior photocatalytic performances of the Fe-doped CeO2 films, compared with undoped CeO2 films, was ascribed mainly to a decrease in band gap energy and an increase in specific surface area of the material. The presence of Fe(3+) as found from XPS analysis, may act as electron acceptor and/or hole donor, facilitating longer lived charge carrier separation in Fe-doped CeO2 films as confirmed by photoluminescence spectroscopy. The 1.50 mol% Fe-doped CeO2 film was found to be the optimal iron doping concentration for MO degradation in this study.

  15. Spectroscopy Study on Crystal Structure of Ce(NO3)3(phen)2 and Interactions of Ce(NO3)3(phen)2 with DNA

    Institute of Scientific and Technical Information of China (English)

    Hu Ruiding; Lin Qiuyue; Huang Wei; Yu Qingsen

    2005-01-01

    The absorption, fluorescence and Raman spectra of Ce(NO3)3(phen)2 complex were assigned and the crystal structure of the complex was studied. Meanwhile the interactions between Ce(NO3)3(phen)2 and DNA were studied by spectrum methods. As DNA was added, it is found that both the UV absorption bands of Ce(NO3)3(phen)2 and the SERS bands of Ce(NO3)3(phen)2 weaken evidently, while the fluorescence intensity of Ce(NO3)3(phen)2 enhance dramatically. The complex compete against EB on the reaction with DNA. It is indicated by this spectrum methods that there are strong interactions between Ce(NO3)3(phen)2 and DNA, and the bond mode is intercalation. The bond constant of the complex with DNA is determined to be 1.7×105.

  16. Pt metal-CeO2 interaction: direct observation of redox coupling between Pt0/Pt2+/Pt4+ and Ce4+/Ce3+ states in Ce(0.98)Pt(0.02)O2-delta catalyst by a combined electrochemical and x-ray photoelectron spectroscopy study.

    Science.gov (United States)

    Sharma, Sudhanshu; Hegde, M S

    2009-03-21

    Pt ions-CeO(2) interaction in Ce(1-x)Pt(x)O(2-delta) (x=0.02) has been studied for the first time by electrochemical method combined with x-ray diffraction and x-ray photoelectron spectroscopy. Working electrodes made of CeO(2) and Ce(0.98)Pt(0.02)O(2-delta) mixed with 30% carbon are treated electrochemically between 0.0-1.2 V in potentiostatic (chronoamperometry) and potentiodynamic (cyclic voltametry) mode with reference to saturated calomel electrode. Reversible oxidation of Pt(0) to Pt(2+) and Pt(4+) state due to the applied positive potential is coupled to simultaneous reversible reduction of Ce(4+) to Ce(3+) state. CeO(2) reduces to CeO(2-y) (y=0.35) after applying 1.2 V, which is not reversible; Ce(0.98)Pt(0.02)O(2-delta) reaches a steady state with Pt(2+):Pt(4+) in the ratio of 0.60:0.40 and Ce(4+):Ce(3+) in the ratio of 0.55:0.45 giving a composition Ce(0.98)Pt(0.02)O(1.74) at 1.2 V, which is reversible. Composition of Pt ion substituted compound is reversible between Ce(0.98)Pt(0.02)O(1.95) to Ce(0.98)Pt(0.02)O(1.74) within the potential range of 0.0-1.2 V. Thus, Ce(0.98)Pt(0.02)O(2-delta) forms a stable electrode for oxidation of H(2)O to O(2) unlike CeO(2). A linear relation between oxidation of Pt(2+) to Pt(4+) with simultaneous reduction in Ce(4+) to Ce(3+) is observed demonstrating Pt-CeO(2) metal support interaction is due to reversible Pt(0)/Pt(2+)/Pt(4+) interaction with Ce(4+)/Ce(3+) redox couple.

  17. A serendipidade na medicina e na anestesiologia

    OpenAIRE

    Vale,Nilton Bezerra do; Delfino,José; Vale,Lúcio Flávio Bezerra do

    2005-01-01

    JUSTIFICATIVA E OBJETIVOS: Neste trabalho foram examinados mais de uma centena dos mais felizes acoplamentos de uma mente brilhante com a sorte benfazeja (serendipidade), através da releitura das mais relevantes histórias sobre invenções e descobertas relacionadas à ciência (n = 46), à Medicina (n = 46) e à Anestesiologia (n = 16). CONTEÚDO: Conceito de serendipidade; exemplos célebres de serendipidade em Ciência e Tecnologia; serendipidade na pesquisa e prática médicas; serendipidade na Anes...

  18. Surrealismo e romance na França

    Directory of Open Access Journals (Sweden)

    Maria Teresa de Freitas

    2011-10-01

    Full Text Available Panorama histórico do surrealismo literário na França e o caminho percorrido pelo romance no interior desse movimento, de modo a se constituir com autonomia frente à linha tradicional do gênero.Panorama historique du surréalisme littéraire en France et le chemin parcourru par le roman à l'intérieur de ce mouvement, de façon à se constituer en tant qu'autonome face à la tradition du genre.

  19. Myxomycetes da Chapada do Araripe (Crato - CE, Brasil Myxomycetes from Chapada do Araripe (Crato, CE, Brazil

    Directory of Open Access Journals (Sweden)

    Laise de Holanda Cavalcanti

    1998-12-01

    Full Text Available Foi efetuado um levantamento dos Myxomyeetes ocorrentes em área de floresta no município do Crato, CE (7º13'53" S; 39º24'28'' W; Alt. 422m, assinalando-se as seguintes famílias e gêneros: Ceratiomyxaceae (Ceratiomyxa, 1 sp.; Cribrariaceae (Cribraria, lsp., Dictydium, 1 sp.; Didymiaceae (Didymium, 2sp.; Enteridiaceae (Dicrydiaethalium, 1sp.; Physaraceae (Badhamia, 2sp., Fuligo, 2sp., Physarum, 5sp.; Steinonitaceae (Comatricha, 3sp., Sfemonitis, 6sp.; Trichiaceae (Arcyria, 3sp., Hemitrichia, 2sp., Periclwena, 1 sp.- Constatou-se preferência das espécies para frutificar em troncos mortos de dicotiledôneas, seguindo-se restos de palmeiras e folhedo. O levantamento eleva para 30 o número de espécies referidas para o Ceará. Uma família e 19 espécies são novos registros para o Estado e Arcyria magna var. rosea Rex é nova referência para o Brasil. São apresentados comentários, chave de identificação e distribuição geográfica das espécies no Nordeste do Brasil.A survey on Myxomycetes was made in the woods of Crato Municipality. State of Ceará, Brazil (7º13'53" S; 39º24,28" W; Alt. 422m. when the following families and genera were registered: Ceratiomyxaceae (Ceratiomyxa, 1 sp.; Cribrariaceae (Cribraria, 1 sp., Dictydium. 1 sp.; Didymiaceae (Didymium, 2sp.; Enteridiaceae Dictydiaethalium, 1 sp.; Physaraceae (Badhamia. 2sp., Fuligo, 2sp., Physarum, 5sp.; Stemonitaceae Comatricha, 3sp., Stemonitis, 6sp.; Trichiaceae (Arcyria, 3sp., Hemitrichia, 2sp., Perichaena, lsp..The species sporulated mostly on dead dicotyledones wood, followed by monocotyledones (Arecaceae debris and litter. The survey raises the number of registers referred to the State of Ceará to 30 species. One family and 19 species are new records for that State while Arcyria magna var. rosea Rex represents a new record for Brazil. Key for the species, comments and geographical distribution in Northeast Brazil arc presented.

  20. Air, aqueous and thermal stabilities of Ce3+ ions in cerium oxide nanoparticle layers with substrates

    KAUST Repository

    Naganuma, Tamaki

    2014-01-01

    Abundant oxygen vacancies coexisting with Ce3+ ions in fluorite cerium oxide nanoparticles (CNPs) have the potential to enhance catalytic ability, but the ratio of unstable Ce3+ ions in CNPs is typically low. Our recent work, however, demonstrated that the abundant Ce3+ ions created in cerium oxide nanoparticle layers (CNPLs) by Ar ion irradiation were stable in air at room temperature. Ce valence states in CNPs correlate with the catalytic ability that involves redox reactions between Ce3+ and Ce4+ ions in given application environments (e.g. high temperature in carbon monoxide gas conversion and immersion conditions in biomedical applications). To better understand the mechanism by which Ce3+ ions achieve stability in CNPLs, we examined (i) extra-long air-stability, (ii) thermal stability up to 500 °C, and (iii) aqueous stability of Ce 3+ ions in water, buffer solution and cell culture medium. It is noteworthy that air-stability of Ce3+ ions in CNPLs persisted for more than 1 year. Thermal stability results showed that oxidation of Ce 3+ to Ce4+ occurred at 350 °C in air. Highly concentrated Ce3+ ions in ultra-thin CNPLs slowly oxidized in water within 1 day, but stability was improved in the cell culture medium. Ce 3+ stability of CNPLs immersed in the medium was associated with phosphorus adsorption on the Ce3+ sites. This study also illuminates the potential interaction mechanisms of stable Ce3+ ions in CNPLs. These findings could be utilized to understand catalytic mechanisms of CNPs with abundant oxygen vacancies in their application environments. © The Royal Society of Chemistry 2014.

  1. Morphology-dependent bactericidal activities of Ag/CeO2 catalysts against Escherichia coli.

    Science.gov (United States)

    Wang, Lian; He, Hong; Yu, Yunbo; Sun, Li; Liu, Sijin; Zhang, Changbin; He, Lian

    2014-06-01

    Silver-loaded CeO2 nanomaterials (Ag/CeO2) including Ag/CeO2 nanorods, nanocubes, nanoparticles were prepared with hydrothermal and impregnation methods. Catalytic inactivation of Escherichia coli with Ag/CeO2 catalysts through the formation of reactive oxygen species (ROS) was investigated. For comparison purposes, the bactericidal activities of CeO2 nanorods, nanocubes and nanoparticles were also studied. There was a 3-4 log order improvement in the inactivation of E. coli with Ag/CeO2 catalysts compared with CeO2 catalysts. Temperature-programmed reduction of H2 showed that Ag/CeO2 catalysts had higher catalytic oxidation ability than CeO2 catalysts, which was the reason for that Ag/CeO2 catalysts exhibited stronger bactericidal activities than CeO2 catalysts. Further, the bactericidal activities of CeO2 and Ag/CeO2 depend on their shapes. Results of 5,5-dimethyl-1-pyrroline-N-oxide spin-trapping measurements by electron spin resonance and addition of catalase as a scavenger indicated the formation of OH, O2(-), and H2O2, which caused the obvious bactericidal activity of catalysts. The stronger chemical bond between Ag and CeO2 nanorods led to lower Ag(+) elution concentrations. The toxicity of Ag(+) eluted from the catalysts did not play an important role during the bactericidal process. Experimental results also indicated that Ag/CeO2 induced the production of intracellular ROS and disruption of the cell wall and cell membrane. A possible production mechanism of ROS and bactericidal mechanism of catalytic oxidation were proposed.

  2. Synthesis and characterization of manganese doped CeO2 nanopowders from hydrolysis and oxidation of Ce37Mn18C45

    Institute of Scientific and Technical Information of China (English)

    DU Yanan; NI Jiansen; HU Pengfei; WANG Jun'an; HOU Xueling; XU Hui

    2013-01-01

    The Mn-doped CeO2 nanopowders with high catalysis activity were successfully fabricated through a simple hydrolyzed-oxidized approach.Firstly,the alloy Ce37Mn18C45 was prepared in vacuum induction melting furnace.Subsequently,Mn-doped CeO2 nanopowders with 142 m2/g of specific surface area were obtained through a simple hydrolyzed-oxidized procedure of the alloy.Those nanopowders were heat treated at different temperatures.The obtained materials were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM),high-resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS).And the catalytic activity on vinyl chloride (VC) emission combustion was investigated.The results showed that those nanopowders after hydrolyzed-oxidized from Ce37Mn1sC45 mainly consisted of CeO2 and Mn3O4.Manganese element increased the thermal stability of CeO2 nanopowders.The Mn-doped CeO2 nanopowders had three morphologies.Small particles were Mn-doped CeO2,square particles were Mn3O4 and the rods were Mn3O4 and Mn2O3.The Mn-doped CeO2 nanopowders had good vinyl chloride (VC) emission catalytic performance.

  3. Characterization of the structure features of CeZrO2 and Ni/CeZrO2 catalysts for tar gasification with steam

    OpenAIRE

    A. Krztoń; L.A. Dobrzański; M. Pawlyta; A. Łamacz

    2011-01-01

    Purpose: The aim of this study was to find out how CeZrO2 and Ni/CeZrO2 structures change after the steam reforming of toluene.Design/methodology/approach: Nickel oxide supported on CeZrO2 (Ni/CeZrO2) with nickel loading of 10 wt. % was prepared by incipient wetness impregnation using an aqueous solution of nickel nitrate. Structure, morphology and chemical composition changes after the steam reforming of toluene were investigated by means of scanning electron microscopy (SEM), energy dispers...

  4. COMPARISION OF THE COLOR PROPERTIES OF COMPOUNDS Ln2Ce2O7 AND Ln2CeZrO7

    OpenAIRE

    B. Hablovicova; P. Sulcova

    2015-01-01

    Pyrochlore type pigments Ln2Ce2O7 and Ln2CeZrO7 (Ln = Nd, Sm, Gd, Dy, Er, Yb and Y) prepared by solid-state reaction were investigated. Effect of rare earths and zirconium ions and calcination temperature (1400, 1500 and 1600oC for Ln2Ce2O7 and 1400, 1450 and 1500 C for Ln2CeZrO7) on their color properties in organic matrix and ceramic glazes, particle size distribution and phase composition were evaluated. The most interesting shades achieve compounds with the highest calcination temperature...

  5. Physical, biochemical and genetic characterization of enterocin CE5-1 produced by Enterococcus faecium CE5-1 isolated from Thai indigenous chicken intestinal tract

    Directory of Open Access Journals (Sweden)

    Kraiyot Saelim

    2015-06-01

    Full Text Available Enterocin CE5-1 produced by Enterococcus faecium CE5-1 isolated from the chicken gastrointestinal tract was active in the wide range of pH 2-10 and temperature 30-100°C and sensitive to proteolytic enzymes and -amylase. It remained active after storage at -20°C for 2 months. Moreover, enterocin CE5-1 showed antibacterial activity against lactobacilli, bacilli, listeria, staphylococci and enterococci, especially antibiotic-resistant enterococci. In vitro study of enterocin CE5-1 decreased the population of Ent. faecalis VanB from 6.03 to 4.03 log CFU/ml. The lethal mode of action of enterocin CE5-1 appeared to be pore and filament formation in the cell wall. PCR sequencing analysis revealed the presence of two open reading frames (ORFs, containing enterocin CE5-1 (entCE5-1 and enterocin immunity (entI gene. Therefore, enterocin CE5-1 from Ent. faecium CE5-1 could possibly be used as an antimicrobial agent to control foodborne pathogen, spoilage bacteria and antibiotic-resistant enterococci in foods, feeds and the environments.

  6. XAFS study of BaCe1-xTixO3 and Ba1-yCe1-xYxO3 protonic solid electrolytes

    Science.gov (United States)

    Seremak-Peczkis, P.; Schneider, K.; Zajączkowski, W.; Kapusta, Cz.; Zając, D. A.; Pasierb, P.; Bućko, M.; Drożdż-Cieśla, E.; Rękas, M.

    2009-10-01

    The paper reports on the doping-influenced evolution of the local structure in a new class of solid electrolytes, BaCe1-xTixO3 and Ba1-yCe1-xYxO3 perovskites, to be used in intermediate temperature fuel cells. The local environments of the Ti, Y and Ce cations were studied by means of X-ray absorption spectroscopy. The Ti XAFS spectra reveal a decrease of the local symmetry of titanium site with increasing doping. The Ce and Y EXAFS functions show a larger amount of oxygen vacancies created by Y doping than that caused by barium understoichiometry.

  7. Influence of NaCl-CaCl2 on Decomposing REPO4 with CaO

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The influence of NaCl-CaCl2 on thermal decomposition of REPO4 (RE: Ce, La, Nd, Th) with CaO was studied.The heat decomposing process of REPO4 was tested with TG-DTA experiments.The results showed that the decomposition temperature of REPO4 with CaO was reduced because of adding NaCl-CaCl2 mixture (NaCl:CaCl2=1:1).The influence of the addition of NaCl-CaCl2, roasting temperature and roasting time on decomposition ratio of REPO4 with CaO was studied.The results showed that the decomposition ratio of REPO4with CaO was 79% when the addition percentage of NaCl-CaCl2 was 10%, the roasting temperature was 750℃, and the roasting time was 1 h.

  8. Aging Behavior of Cu-Cr-Zr-Ce Alloy

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; LIU Ping; SU Juan-hua; TIAN Bao-hong; LI Wei

    2004-01-01

    The aging properties of Cu-0.35Cr-0.038Zr-0.055Ce alloy are studied. The results show that can obtain higher electrical conductivity and microhardness after solutioned at 920℃for lh, and aged at 500℃. The process of precipitation of the secondary phase can be accelerated with cold deformation before aging, so properties of the alloy are improved.Upon aging at 500℃ for 30 minutes after 60% cold deformation, the values of electrical conductivity and microhardness are69.0%IACS and 152HV respectively, but they are only 66.2%IACS and 136HV upon directly aging after solution. With the addition of a trace of rare earth element Ce, the value of microhardness of Cu-0.35Cr-0.038Zr alloy increases 18~25HV,while the value of electrical conductivity drops a little.

  9. Gamma-ray spectroscopy of the nucleus {sup 139}Ce

    Energy Technology Data Exchange (ETDEWEB)

    Bucurescu, D.; Cata-Danil, G.; Cata-Danil, I.; Ivascu, M.; Marginean, N.; Marginean, R.; Mihailescu, L.C.; Rusu, C.; Suliman, G. [Horia Hulubei National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest (Romania)

    2006-03-15

    Gamma-ray coincidence techniques are used to determine new level structures in the N=81 nucleus {sup 139}Ce, at low spins and excitation energies with the {sup 139}La(p,n{gamma}) reaction at 5.0 and 6.0 MeV incident energy, and at high spins with the {sup 130}Te({sup 12}C,3n{gamma}) reaction at 50.5 MeV, respectively. Lifetime determinations are also made in the (p,n{gamma}) reaction with the centroid DSA method. The observed level structures are discussed by comparison with existing calculations and with those in the neighbouring nucleus {sup 140}Ce. (orig.)

  10. Identification and Quality Assessment of Chrysanthemum Buds by CE Fingerprinting

    Directory of Open Access Journals (Sweden)

    Xiaoping Xing

    2015-01-01

    Full Text Available A simple and efficient fingerprinting method for chrysanthemum buds was developed with the aim of establishing a quality control protocol based on biochemical makeup. Chrysanthemum bud samples were successively extracted by water and alcohol. The fingerprints of the chrysanthemum buds samples were obtained using capillary electrophoresis and electrochemical detection (CE-ED employing copper and carbon working electrodes to capture all of the chemical information. 10 batches of chrysanthemum buds were collected from different regions and various factories to establish the baseline fingerprint. The experimental data of 10 batches electropherogram buds by CE were analyzed by correlation coefficient and the included angle cosine methods. A standard chrysanthemum bud fingerprint including 24 common peaks was established, 12 from each electrode, which was successfully applied to identify and distinguish between chrysanthemum buds from 2 other chrysanthemum species. These results demonstrate that fingerprint analysis can be used as an important criterion for chrysanthemum buds quality control.

  11. Polarized neutron diffraction study of CePd{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Givord, F.; Galera, R.M.; Murani, A.P.; Lelievre-Berna, E

    2004-07-15

    We have performed polarized neutron diffraction measurements on the intermediate valence compound CePd{sub 3} using the D3 spectrometer at the ILL. The results show that at low temperatures, 1.7 K, as well as at 100 K, the field-induced magnetic amplitudes measured in a field of 4.6 T could be interpreted in terms of two contributions: a 4f-type contribution with a Ce{sup 3+} form factor, and an extra delocalized contribution (relatively narrow in q-extent). In particular, we find that the values of the 4f moment deduced from the extrapolation of the neutron data to Q=0 are systematically lower than the values deduced from bulk magnetization measurements performed on the same sample. This difference can be ascribed to a possible positive polarization of the conduction band which is similar at both temperatures.

  12. Thermal Conductivity of Ce Doped Bi-2212 Superconductors

    Institute of Scientific and Technical Information of China (English)

    LI Bo; WU Bai-Mei; M.Ausloos

    2004-01-01

    The temperature dependence of the thermal conductivity in Bi2Sr2 Ca1-x Cex Cu2Oy x = 0.1, 0.2, 0.3, 0.4 is presented. With increasing Ce-doping level, the thermal conductivity peak under TC is suppressed then disappears,while another peak appears at low temperatures for the non-superconducting compounds. The numerical analysis shows that the thermal conductivity peak under TC can be well described by the normal electron relaxation-time contribution model, and the phonon-induced thermal conductivity peak could be well described within the Debye approximation of the phonon spectrum. The existence and variation of these two thermal conductivity peaks indicate the adjustability between the superconducting and insulating components in the samples with different Ce-doping levels.

  13. Ni-CeO2 Cermets Synthesis by Solid State Sintering of Ni/CeO2 Multilayer

    Directory of Open Access Journals (Sweden)

    Aleksandras ILJINAS

    2013-12-01

    Full Text Available Nickel and gadolinium doped cerium oxide (GDC cermet is intensively investigated for an application as an anode material for solid oxide fuel cells based on various electrolytes. The purpose of the present investigation is to analyze morphology, microstructure, and optical properties of deposited and annealed for one hour in the temperatures from 500 ºC to 900 ºC Ni/CeO2 multilayer thin films deposited by sputtering. The crystallographic structure of thin films was investigated by X-ray diffraction. The morphology of the film cross-section was investigated with scanning electron microscope. The elemental analysis of samples was investigated by energy-dispersive X-ray spectroscopy. The fitting of the optical reflectance data was made using Abeles matrix method that is used for the design of interference coatings. The film cross-section of the post-annealed samples consisted of four layers. The first CeO2 layer (on Si had the same fine columnar structure with no features of Ni intermixing. The part of Ni (middle-layer after annealing was converted to NiO with grain size exceeding 100 nm. The CeO2 layer deposited on Ni was divided into two layers. Lower layer had small grains not exceeding 25 nm and consisting of NiO and CeO2 mixture. Upper layer consisted of CeO2 columns with approximate thickness of 50 nm. Ni sample annealed at 600 ºC was fully oxidized. The NiO thickness and refraction index were almost steady after annealing in various temperatures. The approximation of experimental reflectance data was successful only for the samples with one transparent homogeneous layer. The reflectance of the Ni/CeO2 samples annealed at intermediate temperatures could not be fitted using one-layer or three-layer model. That may show that a simplified model could not be implemented.  The real system has complicated distribution of refraction index. DOI: http://dx.doi.org/10.5755/j01.ms.19.4.3073

  14. Electron spectroscopic investigation of metal-insulator transition in Ce1-SrTiO3

    Indian Academy of Sciences (India)

    U Manju; S R Krishnakumar; Sugata Ray; S Raj; M Onoda; C Carbone; D D Sarma

    2003-10-01

    We have carried out detailed electron spectroscopic investigation of Ce1-SrTiO3 exhibiting insulator-metal transition with . Core level X-ray photoelectron spectra of Ce 3 as well as resonant photoemission spectra obtained at the Ce 4 → 4 resonant absorption threshold establish Ce as being in the trivalent state throughout the series. Using the `off-resonance’ condition for Ce 4 states, we obtain the Ti 3 dominated spectral features close to , exhibiting clear signatures of coherent and incoherent peaks. We discuss the implications of our findings in relation to the metal-insulator transition observed in this series of compounds.

  15. Violet/blue photoluminescence from CeO2 thin film

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    CeO2 thin film was fabricated by dual ion beam epitaxial technique. The violet/blue PL at room temperature and lower temperature was observed from the CeO2 thin film. After the analysis of crystal structure and valence in the compound was carried out by the XRD and XPS technique, it was inferred that the origin of CeO2 PL was due to the electrons transition from Ce4f band to O2p band and the defect level to O2p band. And these defects levels were located in the range of 1 eV around Ce4f band.

  16. Influence of CeO_2 on scintillating properties of Tb~(3+)-doped silicate glasses

    Institute of Scientific and Technical Information of China (English)

    孙心瑗; 顾牡; 张敏; 黄世明

    2010-01-01

    A series of Tb3+-,Ce3+-doped,and Tb3+/Ce3+-codoped silicate glasses were synthesized by melt-quenching technique.Some properties of the investigated glasses were characterized by X-ray photoelectron spectroscopy(XPS),photoluminescence(PL),X-ray excited luminescence(XEL) and thermoluminescence(TL) spectra.The result of XPS revealed that both Ce3+ and Ce4+ ions coexisted in these silicate glasses,and energy transfer from Ce3+ to Tb3+ ions was observed under UV excitation.However,under X-ray excitation the XEL...

  17. Sequential microfluidic flow synthesis of CePO4 nanorods decorated with emission tunable quantum dots.

    Science.gov (United States)

    Fang, Jie; Evans, Cameron W; Willis, Glen J; Sherwood, David; Guo, Yanglong; Lu, Guanzhong; Raston, Colin L; Iyer, K Swaminathan

    2010-10-07

    CePO(4) nanorods decorated with QDs (QDs@CePO(4)) can be prepared in a sequential, aqueous procedure under continuous flow using a rotating tube processor and a narrow channel reactor. The emission from the QD@CePO(4) is tunable from green to red by simply adjusting the feeding rate, which in turn regulates the particle size of the QDs. The Ce(3+) ions in the QDs@CePO(4) serve as an efficient fluorescence resonance energy transfer (FRET) donor, effectively enlarging the Stokes shift of the QDs.

  18. The application of Ce-Zr oxide solid solution to oxygen storage promoters in automotive catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ozawa, Msakuni (Toyota Central Research and Development Labs. Inc., Aichi (Japan)); Kimura, Mareo (Toyota Central Research and Development Labs. Inc., Aichi (Japan)); Isogai, Akio (Toyota Central Research and Development Labs. Inc., Aichi (Japan))

    1993-03-15

    The complex oxides in the CeO[sub 2]-ZrO[sub 2] system were examined for the improvement of oxygen storage capacity in automotive catalysts. The formation of Ce-Zr oxide solid solution improved the thermal stability and activity of CeO[sub 2]. The Ce-Zr addition enhanced the removal activity for CO, NO[sub x] and hydrocarbons under dynamic air-fuel ratio condition. The automotive catalyst was designed and developed through research on the oxides in the CeO[sub 2]-ZrO[sub 2] system. (orig.)

  19. Nouvelle espèce des Syntomides (Lepidoptera Heterocera)

    NARCIS (Netherlands)

    Snellen, P.C.T.

    1886-01-01

    Quatre mâles frais et bien conservés de 58—64 millim. d’envergure. Cette nouvelle espèce, gigantesque pour une Syntomide, appartient au genre Automolis, tel qu’il a été défini par Herrich-Schäffer, dans son ouvrage »Sammlung aussereuropäischer Schmetterlinge” (p. 21); le nom est emprunté au bien con

  20. Burstein Moss effect in nanocrystalline CaS : Ce

    Indian Academy of Sciences (India)

    Geeta Sharma; Puja Chawla; S P Lochab; Nafa Singh

    2011-07-01

    The nanocrystalline CaS : Ce nanophosphors are synthesized by wet chemical co-precipitation method. The particles possess an average size of 10 nm as calculated using Debye–Scherrer formula. The particle size and the crystalline nature of the formed nanoparticles are confirmed by TEM micrograph. The optical studies are carried out using UV–Vis absorption spectroscopy. The absorption edge is found to show blue shift with increasing cerium concentration. The shift may be attributed to Burstein Moss effect.

  1. Contamination in LaCl3:Ce Scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Milbrath, Brian D.; McIntyre, Justin I.; Runkle, Robert C.; Smith, Leon E.

    2005-12-01

    The gamma-, beta-, and x-ray-contamination in LaCl3:Ce scintillators due to the presence of the naturally occurring radioisotope La-138 is discussed. As the size of lanthanum halide crystals grows towards commercially useful sizes, and the effects of alpha-contamination due to Ac-227 has been substantially reduced, the effects of La-138 in background and low-count spectra become more problematic. The crystal's performance in high neutron fluxes is also examined.

  2. Itinerant magnetism in CeRh3B2

    OpenAIRE

    1989-01-01

    Spin-polarized energy-band calculations, including spin-orbit coupling in the band Hamiltonian, have been performed on CeRh3B2. Good agreement is obtained between theory and experiment concerning the magnetic moment. It is also found that the magnetic moment varies strongly with volume and from this a qualitative explanation for the anomalously high Curie temperature of the compound is proposed. Furthermore, the spin density is found to be highly nonspherical.

  3. Itinerant magnetism in CeRh3B2

    Science.gov (United States)

    Eriksson, Olle; Johansson, Börje; Brooks, M. S. S.; Skriver, H. L.; Sjöström, Jörgen

    1989-09-01

    Spin-polarized energy-band calculations, including spin-orbit coupling in the band Hamiltonian, have been performed on CeRh3B2. Good agreement is obtained between theory and experiment concerning the magnetic moment. It is also found that the magnetic moment varies strongly with volume and from this a qualitative explanation for the anomalously high Curie temperature of the compound is proposed. Furthermore, the spin density is found to be highly nonspherical.

  4. Proposal for product development model focused on ce certification methodology

    Directory of Open Access Journals (Sweden)

    Nathalia Marcia Goulart Pinheiro

    2015-09-01

    Full Text Available This paper presents a critical analysis comparing 21 product development models in order to identify whether these structures meet the demands Product Certification of the European Community (CE. Furthermore, it presents a product development model, comprising the steps in the models analyzed, including improvements in activities for referred product certification. The proposed improvements are justified by the growing quest for the internationalization of products and processes within companies.

  5. Structure of ∼130 nuclei in La–Ce region

    Indian Academy of Sciences (India)

    Tumpa Bhattacharjee

    2010-07-01

    The variety of shapes and structures, observed in light rare earth $A ∼ 130$ nuclei, have been discussed in view of different angular momentum coupling schemes and their interplay that comes into effect at high spin. The = 79 and 80 isotopes in La–Ce region, produced via fusion evaporation reaction, have been studied using the Indian National Gamma Array (INGA) consisting of 18 clover HPGe detectors. Two nearly degenerate = 1 bands have been observed at high spin of 137Ce and a triaxial deformation of = ± 30°$ has been assigned to the bands, from the total Routhian surface (TRS) calculations. The high-spin candidates of the yrast band of 138Ce show signature splitting both in energy and (1)/(2) values. The bandcrossing due to the alignment of a pair of ℎ11/2 proton particles has been conjectured at ħ ω ∼ 0.3 MeV, from the single-particle Routhians obtained from TRS calculations. Lifetime measurements by Doppler shift attenuation method (DSAM) has been carried out and from the estimated reduced transition probability (1), the = 1 band in 138Ce has been characterized as a magnetic rotation (MR) band. The rise in the values of (1), for the higher spin candidates of the band, has been conjectured as the reopening of a different shear at the top of the Band B1. The characteristic of the MR bands in ∼ 130 region has been discussed in the light of a phenomenological calculation and compared to the MR bands in other mass regions.

  6. 超便携PC亮相CeBit

    Institute of Scientific and Technical Information of China (English)

    胡纲

    2006-01-01

    微软终于在德国汉诺威举行的CeBIT 2006科技展示上揭开了所谓Origami项目的神秘面纱:原来这是一种使用Windows XP Tablet操作系统,具有触摸屏和无线连接的超便携PC (UltraMobile PC,简称UMPC)。

  7. Collective magnetic response of CeO2 nanoparticles

    Science.gov (United States)

    Coey, Michael; Ackland, Karl; Venkatesan, Munuswamy; Sen, Siddhartha

    2016-07-01

    The magnetism of nanoparticles and thin films of wide-bandgap oxides that include no magnetic cations is an unsolved puzzle. Progress has been hampered by both the irreproducibility of much of the experimental data, and the lack of any generally accepted theoretical explanation. The characteristic signature is a virtually anhysteretic, temperature-independent magnetization curve that saturates in an applied field that is several orders of magnitude greater than the magnetization. It would seem as if a tiny volume fraction, sugar or latex microspheres. The saturation magnetization, Ms ≍ 60 A m-1 for compact samples, is maximized by 1 wt% lanthanum doping. Dispersing the CeO2 nanopowder reduces its magnetic moment by up to an order of magnitude, and there is a characteristic length scale of order 100 nm for the magnetism to appear in CeO2 nanoparticle clusters. The phenomenon is explained in terms of a giant orbital paramagnetism that appears in coherent mesoscopic domains due to resonant interaction with zero-point fluctuations of the vacuum electromagnetic field. The theory explains the observed temperature-independent magnetization curve and its doping and dispersion dependence, based on a length scale of 300 nm that corresponds to the wavelength of a maximum in the ultraviolet absorption spectrum of the magnetic CeO2 nanoparticles. The coherent domains occupy roughly 10% of the sample volume.

  8. Magnetoresistance in CePtSn under high hydrostatic pressures

    Energy Technology Data Exchange (ETDEWEB)

    Misek, M. [Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague (Czech Republic)], E-mail: martinmisek@hotmail.com; Prokleska, J.; Javorsky, P.; Sechovsky, V. [Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague (Czech Republic)

    2009-07-01

    We report the evolution of magnetic-history dependent antiferromagnetic phases in CePtSn. We concentrate on the magnetoresistance in magnetic fields up to 14 T applied along the crystallographic b-axis, measured on a CePtSn single crystal subjected to hydrostatic pressure (p {<=} 2.2 GPa) generated in a double-layered CuBe/NiCrAl piston cylinder cell. We observe a gradual increase of the critical field B{sub c}{sup LF} of the low field (LF) transition up to {approx}1.2 GPa where only one transition is observed at {approx}11.5 T. For pressures above 1.2 GPa we observe two transitions again and B{sub c}{sup LF} decreases with further increasing pressure to reach B{sub c}{sup LF}{approx}7.5T at 2.5 GPa. The position of the high field (HF) transition remains almost unaffected by applied pressure. A scenario considering the spin-slip AF structure in CePtSn is briefly discussed.

  9. Optical properties of CeO2 thin films

    Indian Academy of Sciences (India)

    S Debnath; M R Islam; M S R Khan

    2007-08-01

    Cerium oxide (CeO2) thin films have been prepared by electron beam evaporation technique onto glass substrate at a pressure of about 6 × 10-6 Torr. The thickness of CeO2 films ranges from 140–180 nm. The optical properties of cerium oxide films are studied in the wavelength range of 200–850 nm. The film is highly transparent in the visible region. It is also observed that the film has low reflectance in the ultra-violet region. The optical band gap of the film is determined and is found to decrease with the increase of film thickness. The values of absorption coefficient, extinction coefficient, refractive index, dielectric constant, phase angle and loss angle have been calculated from the optical measurements. The X-ray diffraction of the film showed that the film is crystalline in nature. The crystallite size of CeO2 films have been evaluated and found to be small. The experimental -values of the film agreed closely with the standard values.

  10. NMR study of CeTe at low temperatures

    Science.gov (United States)

    Hinderer, J.; Weyeneth, S. M.; Weller, M.; Gavilano, J. L.; Felder, E.; Hulliger, F.; Ott, H. R.

    2006-05-01

    We present 125Te NMR measurements on CeTe powder at temperatures between 1 and 150 K and in magnetic fields between 5 and 8 T. CeTe is a rocksalt-type intermetallic compound. It orders antiferromagnetically at TN≈2.2 K with a much reduced ordered moment [H.R. Ott, J.K. Kjems, F. Hulliger, Phys. Rev. Lett. 42 20 (1979) 1378]. From our low-temperature NMR spectra we infer the presence of at least three inequivalent Te sites at low temperatures. Considering the crystal structure this result is completely unexpected. The linewidths and the Knight shifts of the individual lines are significantly different and increase substantially with decreasing temperature. They follow the temperature dependence of the magnetic susceptibility above 20 K. Above TN, hyperfine fields of 1.6, 0.8 and 0.0 T at the three Te sites per Bohr magneton of Ce moment are deduced from Knight shift vs. magnetic susceptibility data. These values are typical for transferred hyperfine fields via conduction electrons.

  11. Alumina/Ce-Tzp Functionally Graded Materials by Electrophoretic Deposition

    Institute of Scientific and Technical Information of China (English)

    C.Zhao, J.Vleugels; O.Van Der Biest

    2000-01-01

    Cylindrical Al2O3/Ce-TZP functionally graded composites were fabricated by electrophoretic deposition and pressureless sintering in air. A continuous change in composition was realized by changing the composition of the suspension during deposition. In order to achieve full densification, a temperature above 1550℃ was necessary. The resultant FGM cylinder with a diameter of 5.6 mm shows the following structure: a central hole with a diameter less than 0.5 mm, a tough Ce-ZrO2 core with a diameter of about 3 mm, a gradient layer of about 1 mm, and a hard Al2O3-rich surface layer. The Ce-ZrO2 core has a Vickers hardness between 10and 11 GPa and an excellent toughness (>10 MPa√m). In the gradient layer, hardness and toughness vary continuously along the radius. The surface layer has a hardness of 15.5 GPa and a modest toughness of 2.5MPa√m.

  12. Synthesis and Characterization of Ce-Containing MCM-41

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ SUMMARY. The cerium-containing MCM-41 (Ce-MCM-41) has been synthesized with size in the micrometer range by direct hydrothermal method. Transmission electron microscopy shows the regular hexagonal array of uniform channel characteristics of MCM-41. Five peaks were detected in the lov-angle XRD patterns,an interplanar spacing d100 = 40.6 A was obtained that can be indexed on a hexagonal unit cell with a0 = 46.9 A. Nitrogen adsorption isotherm at 77 K revealed a surface area of 920 m2/g, pore size of 26.2 A and wall thickness of 18.1 A. A cell contraction of 2.6 A upon calcination was observed. The spectroscopic studies indicate that the synthesized sample is with MCM-41 structure and Ce is in the framework position. A weak Lewis acidity was indicated by infrared spectra of pyridine adsorption. The synthesized Ce-MCM-41 exhibits fairly catalytic activity for the NO reduction by CO.

  13. Synthesis and Characterization of Ce-Containing MCM-41

    Institute of Scientific and Technical Information of China (English)

    CHIEN; ShuHua

    2001-01-01

    SUMMARY.  The cerium-containing MCM-41 (Ce-MCM-41) has been synthesized with size in the micrometer range by direct hydrothermal method. Transmission electron microscopy shows the regular hexagonal array of uniform channel characteristics of MCM-41. Five peaks were detected in the lov-angle XRD patterns,an interplanar spacing d100 = 40.6 A was obtained that can be indexed on a hexagonal unit cell with a0 = 46.9 A. Nitrogen adsorption isotherm at 77 K revealed a surface area of 920 m2/g, pore size of 26.2 A and wall thickness of 18.1 A. A cell contraction of 2.6 A upon calcination was observed. The spectroscopic studies indicate that the synthesized sample is with MCM-41 structure and Ce is in the framework position. A weak Lewis acidity was indicated by infrared spectra of pyridine adsorption. The synthesized Ce-MCM-41 exhibits fairly catalytic activity for the NO reduction by CO.  ……

  14. Unusual Compression Behavior of Nanocrystalline CeO2

    Science.gov (United States)

    Wang, Qiming; He, Duanwei; Peng, Fang; Lei, Li; Liu, Pingping; Yin, Shuai; Wang, Pei; Xu, Chao; Liu, Jing

    2014-01-01

    The x-ray diffraction study of 12 nm CeO2 was carried out up to ~40 GPa using an angle dispersive synchrotron-radiation in a diamond-anvil cell with different pressure transmitting medium (PTM) (4:1 methanol: ethanol mixture, silicone oil and none) at room temperature. While the cubic fluorite-type structure CeO2 was retained to the highest pressure, there is progressive broadening and intensity reduction of the reflections with increasing pressure. At pressures above 12 GPa, an unusual change in the compression curve was detected in all experiments. Significantly, apparent negative volume compressibility was observed at P = 18–27 GPa with silicone oil as PTM, however it was not detected in other circumstances. The expansion of the unit cell volume of cubic CeO2 was about 1% at pressures of 15–27 GPa. To explain this abnormal phenomenon, a dual structure model (hard amorphous shell and relatively soft crystalline core) has been proposed. PMID:24658049

  15. Radon gamma-ray spectrometry with YAP:Ce scintillator

    CERN Document Server

    Plastino, W; De Notaristefani, F

    2002-01-01

    The detection properties of a YAP:Ce scintillator (YAlO sub 3 :Ce crystal) optically coupled to a Hamamatsu H5784 photomultiplier with standard bialkali photocathode have been analyzed. In particular, the application to radon and radon-daughters gamma-ray spectrometry was investigated. The crystal response has been studied under severe extreme conditions to simulate environments of geophysical interest, particularly those found in geothermal and volcanic areas. Tests in water up to a temperature of 100 deg.C and in acids solutions such as HCl (37%), H sub 2 SO sub 4 (48%) and HNO sub 3 (65%) have been performed. The measurements with standard radon sources provided by the National Institute for Metrology of Ionizing Radiations (ENEA) have emphasized the non-hygroscopic properties of the scintillator and a small dependence of the light yield on temperature and HNO sub 3. The data collected in this first step of our research have pointed out that the YAP:Ce scintillator can allow high response stability for rad...

  16. Práce s databází SQL SERVER 2005 v prostředí Framework.NET a programovacím jazyku C++/CLI

    OpenAIRE

    2007-01-01

    Obsah práce je zaměřen na vývoj aplikací pro platformu .NET Framework se zaměřením na jazyk C++/CLI v interakci s databází SQL Server 2005. Zaměření především na vývojové možnosti na straně SQL Server 2005 (T-SQL) a na přehled prostředků, které nabízí .NET Framework jako podporu k připojení databáze k aplikacím.

  17. Preparation and catalytic behavior of CeO2 nanoparticles on Al2O3 crystal

    Science.gov (United States)

    Hattori, Takashi; Kobayashi, Katsutoshi; Ozawa, Masakuni

    2017-01-01

    In this work, we examined the preparation, morphology, and catalytic behavior of CeO2 nanoparticles (NPs) on Al2O3(0001) crystal substrates. A CeO2 NP layer was prepared by the dipping method using a CeO2 nanocrystal colloid solution. Even after heat treatment at 1000 °C, the CeO2 NP layer maintained the granular morphology of CeO2 with a grain diameter of less than 40 nm. CeO2 NPs on an Al2O3 crystal showed higher oxidation activity for gaseous hydrogen at moderate temperatures and enhanced oxygen release properties of CeO2, compared with CeO2 powder. This was due to the highly dispersed CeO2 NPs and the interaction between CeO2 NPs and Al2O3; this clarified the importance of the Al2O3 support for the CeO2 catalyst.

  18. Enhancement of room temperature ferromagnetic behavior of rf sputtered Ni-CeO2 thin films

    Science.gov (United States)

    Murugan, R.; Vijayaprasath, G.; Mahalingam, T.; Ravi, G.

    2016-12-01

    Ni-doped CeO2 thin films were prepared under Ar+ atmosphere on glass substrates using rf magnetron sputtering. To assess the properties of the prepared thin films, the influence of various amounts of Ni dopant on structural, morphological, optical, vibrational, compositional and magnetic properties of the CeO2 films were studied by using X-Ray diffraction (XRD), atomic force microscope (AFM), photoluminescence (PL), micro-Raman, X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM). XRD patterns for all the samples revealed the expected CeO2 cubic fluorite-type structure and Ni ions were uniformly distributed in the samples. AFM images of the prepared samples indicate high dense, columnar structure with uniform distribution of CeO2. Room-temperature photoluminescence (PL) and micro-Raman spectroscopic studies revealed an increase of oxygen vacancies with higher concentration of Ni in CeO2. XPS results confirm the presence of Ni2p, O1s and Ce and depict that cerium is present as both Ce4+ and Ce3+ oxidation states in Ce1-xNixO2 (x = 15%) thin film. Field dependent magnetization measurements revealed a paramagnetic behavior for pure CeO2, while a ferromagnetic behavior appeared when Ni is doped in CeO2 films. Doping dependent magnetization measurements suggest that the observed ferromagnetism is due to the presence of metallic Ni clusters with nanometric size and broad size distribution.

  19. Preparation and characterization of CNT-CeO{sub 2} nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Jasmeet, E-mail: jasmeet.dayal@gmail.com; Anand, Kanika; Singh, Ravi Chand [Department of Physics, Guru Nanak Dev University, Amritsar-143005 (India)

    2015-06-24

    This paper reports decoration of CeO{sub 2} nanoparticles on multi-walled carbon nanotubes through a reflux process in which Ce (NO{sub 3}) {sub 3}·6H{sub 2}O serves as precursor and hydrazine hydrate (N{sub 2}H{sub 4}.H{sub 2}O) as reducing agent. Successful deposition of cubic fluorite CeO{sub 2} nanoparticles onto multi-walled carbon nanotubes has been confirmed by x-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy (EDS). It was found that CeO{sub 2} nanoparticles formed in the presence of CNTs were larger as compared to pure CeO{sub 2} nanoparticles. Raman analysis showed that CeO{sub 2} induced a decrease in the size of the carbon grain in the CNTs. A red shift from 460 cm{sup −1} to 463 cm{sup −1} for F{sub 2g} mode of CeO{sub 2} has also been observed in Raman spectra of CNT- CeO{sub 2} nanocomposite as compared to pure CeO{sub 2}. The CeO{sub 2} coated multi-wall carbon nanotubes (CNT-CeO{sub 2}) nanocomposite would be a promising candidate for practical applications such as catalysis, sensing and power source applications.

  20. Temperature Programmed Reduction Studies on CeO2-Containing Catalysts

    Institute of Scientific and Technical Information of China (English)

    Noriyoshi Kakuta; Harunobu Ohkita; Takanori Mizushima

    2004-01-01

    Temperature programmed reduction (TPR) study was carried out for CeO2/Al2O3 and CeO2/ZrO2 catalysts to evaluate oxygen storage property induced by a facile redox cycling of Ce ion. The CeO2/ZrO2 catalyst possesses excellent oxygen storage activity at 373 K after reduction above 1173 K although the oxygen storage of CeO2/Al2O3 catalyst after reduction above 1173 K is poor because of the formation of CeAlO3. Consequently, the oxygen storage on the CeO2/ZrO2 catalyst smoothly occurs from low temperatures when the catalyst is reduced even at high temperatures.

  1. Interaction at Pt-CeO2 Contact Interface over Pt/CeO2/SBA-15 Catalyst%Pt/CeO2/SBA-15催化剂上Pt-CeO2接触界面的相互作用

    Institute of Scientific and Technical Information of China (English)

    毕亚东; 张微; 徐恒泳; 李文钊

    2009-01-01

    通过沉积沉淀法(Deposition precipitation,DP)将CeO2纳米粒子高度分散在SBA-15分子筛上,进一步采用浸渍法负载Pt后制备了 Pt/CeO2/SBA-DP催化剂.紫外-可见漫反射光谱分析表明,在Pt/CeO2/SBA-DP催化剂上可以形成更多的Pt-CeO2接触界面,有利于从CeO2到Pt的电子转移过程.CO程序升温还原(CO-TPR)测试证实,Pt/CeO2/SBA-DP催化剂上CeO2表面氧物种具有较高的还原能力.

  2. Investigation of the isothermal section of the Ce-Co-Al ternary system at 573 K

    Institute of Scientific and Technical Information of China (English)

    YAO Qingrong; ZHOU Huaiying; TANG Chengying; PAN Shunkang

    2011-01-01

    The isothermal section of the Ce-Co-Al ternary system at 573 K was investigated by X-ray powder diffraction (XRD),scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) techniques.It consisted of 19 single-phase regions,46 two-phase regions and 25 three-phase regions.Four ternary compounds,namely CeCoAl,Ce2Co15Al2,CeCoAl4,CeCo2Al8,were confirmed in this system.At 573 K,the maximum solid solubilities of Co in CeAl2 and A1 in CeCo2 were about 10.4 at.% and 10.0 at.%,respectively.The homogeneity range of CoAl phase extended from about 46.0 to 56.0 at.% Al.

  3. Ferromagnetic enhancement in the hexagonal Ce(Rh1-xIrx)3B2 system

    Science.gov (United States)

    Hsu, S. W.; Ku, H. C.

    1988-08-01

    Electrical resistivity, magnetization, and crystallographic measurements have been carried out for the pseudoternary system Ce(Rh1-xIrx)3B2. A single-phase hexagonal CeCo3B2-type structure persists from x=0.0 up to x0.95. The ferromagnetic Curie temperature Tc is enhanced from 115 K for CeRh3B2 to 125 K for Ce(Rh0.8Ir0.2)32, then decreases slowly to 118 K at x=0.5 before decreasing sharply to 69 K at x=0.67, even though the magnetic moment per Ce ion decreases monotonically with increasing Ir substitution. The Tc of 125 K in Ce(Rh0.8Ir0.2)3B2 is the highest magnetic-ordering temperature observed so far for all Ce-based systems with nonmagnetic constituents.

  4. Energy transfer from Ce~(3+) to Tb~(3+) and Eu~(3+) in zinc phosphate glasses

    Institute of Scientific and Technical Information of China (English)

    马崇庚; 江莎; 周贤菊

    2010-01-01

    Ce3+,Eu3+ and Tb3+ singly doped and Ce3+/Eu3+ and Ce3+/Tb3+ co-doped zinc phosphate glasses were prepared by sintering P2O5,ZnO,Ce2(C2O4)3·10H2O and Eu2O3/Tb4O7 mixtures at 1200 °C in the air for 2 h and then annealing at 450 °C for 10 h.The obtained glasses were homogeneous and transparent.The glasses without Ce3+ were colorless and those with Ce3+ showed slightly yellow.The singly doped glasses showed strong emissions and excitations from doped trivalent rare earth ions.Strong energy transfer from Ce3+ to...

  5. Structural Perceptions and Mechanical Evaluation of β-Ca3(PO4)2/c-CeO2 Composites with Preferential Occupancy of Ce(3+) and Ce(4).

    Science.gov (United States)

    Nandha Kumar, Ponnusamy; Mishra, Sandeep Kumar; Kannan, Sanjeevi

    2017-02-24

    The role of cerium in the formation of stable β-Ca3(PO4)2/c-CeO2 composites and their structural analysis with varied compositional ratios were investigated. The composite formation was attempted through an in situ precipitation technique, and the gradual structural changes during heat treatments to yield the pure form of β-Ca3(PO4)2/c-CeO2 composites was presented. The cerium was found in Ce(3+) and Ce(4+) oxidation states in composites. Ce(3+) prefers to occupy the Ca(2+)(1), Ca(2+)(2), and Ca(2+)(3) sites of β-Ca3(PO4)2, whereas, beyond the saturation occupancy limit, excess cerium prefers to crystallize in the form of thermodynamically stable cubic ceria (c-CeO2). A uniform expansion of the β-Ca3(PO4)2 unit cell and the delayed allotropic conversion of β-Ca3(PO4)2 → α-Ca3(PO4)2 have been detected due to the Ce(3+) occupancy at the β-Ca3(PO4)2 lattice. β-Ca3(PO4)2/c-CeO2 composites exhibited a steady upsurge in the mechanical properties with consistent enhancement of c-CeO2 content in the composites. The overall results from the investigation imply the appropriateness of the β-Ca3(PO4)2/c-CeO2 composites for applications in hard tissue replacements.

  6. CO catalytic oxidation over Au/CeO2 catalysts%Au/CeO2催化CO氧化反应行为研究

    Institute of Scientific and Technical Information of China (English)

    李卫力; 葛庆杰; 徐恒泳

    2016-01-01

    通过考察不同比表面积CeO2载体和催化剂预处理条件对Au/CeO2催化CO氧化反应性能的影响,研究了影响Au/CeO2催化活性的关键因素及催化剂表面氧活化行为和反应机理。结果表明,含有不同比表面积CeO2载体的Au/CeO2催化剂具有不同的CO氧化反应活性,其中以Au/CeO2-89.0的催化性能最佳。 O2预处理有利于催化剂的反应性能,而H2预处理则明显降低了催化剂的反应活性。载体CeO2的表面晶格氧可参与Au/CeO2表面的CO氧化反应,表面晶格氧和CO反应形成CO2并脱附后,形成氧空位,然后气相中的O2填补氧空位,重新形成晶格氧,形成氧化还原循环,维持反应的持续进行。%The influences of CeO2 supports with different surface areas and pretreatment conditions on the CO oxidation over the Au/CeO2 catalysts were investigated experimentally. Based on which, the key factors affecting the activity of catalyst and the surface oxygen activation behavior and reaction mechanism of the catalyst were discussed. Results shows that Au/CeO 2 catalysts with different CeO2 supports had different CO oxidation activities, among which Au/CeO2-89.0 exhibited the best. O2 pretreatment of Au/CeO2 could improve its catalytic activity while H2 pretreatment evidently decrease the catalytic activity. Lattice oxygen participates in the CO oxidation on the surface of Au/CeO2. Lattice oxygen reacts with adsorbed CO to form CO2, and then oxygen vacancies form on the catalyst surface. The oxygen vacancies could react with gas phase O2 to form lattice oxygen again. Such recycling keeps the running of CO oxidation over Au/CeO2 catalyst.

  7. Experimental and theoretical study about sulfur deactivation of Ni/ CeO{sub 2} and Rh/CeO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ocsachoque, Marco A., E-mail: ocmarco@quimica.unlp.edu.ar [Centro de Investigación y Desarrollo en Ciencias Aplicadas “Dr Jorge J. Ronco”, (CONICET, CCT La Plata), Departamento de Química, Facultad de Cs Exactas (UNLP), Calle 48 N° 257, 1900 La Plata (Argentina); Eugenio Russman, Juan I.; Irigoyen, Beatriz [Instituto de Tecnologías del Hidrógeno y Energías Sostenibles (ITHES), Departamento de Ingeniería Química, Facultad de Ingeniería (UBA), Buenos Aires (Argentina); Gazzoli, Delia [Dipartimento di Chimia, Universitá di Roma “La Sapienza”, Roma (Italy); González, María G. [Centro de Investigación y Desarrollo en Ciencias Aplicadas “Dr Jorge J. Ronco”, (CONICET, CCT La Plata), Departamento de Química, Facultad de Cs Exactas (UNLP), Calle 48 N° 257, 1900 La Plata (Argentina)

    2016-04-01

    Sulfur deactivation of Ni/CeO{sub 2} and Rh/CeO{sub 2} catalysts were examined through an experimental and theoretical study. These catalysts were characterized by N{sub 2} adsorption, X-ray diffraction, temperature programmed reaction, thermogravimetric analysis, Uv–visible spectroscopy and Raman spectroscopy, and tested under the methane dry reforming reaction in the presence of H{sub 2}S. On the other hand, different possible interactions of sulfur with Rh, Ni or surface sites of the CeO{sub 2} support were evaluated by performing energy calculations with the density functional theory (DFT). Overall, the results indicate that tolerance to sulfur of Rh/CeO{sub 2} catalyst is higher than that of Ni/CeO{sub 2} one. In this sense, TPR measurements show that reduction of CeO{sub 2} is promoted by the presence of Rh. This effect, probably caused by hydrogen spillover to CeO{sub 2} support during the reduction of RhO{sub x} species, could be linked to a high oxygen donation capacity of Rh/CeO{sub 2} catalysts. Accordingly, the O{sup 2−} species existing on Rh/CeO{sub 2} catalysts, revealed by Raman spectra of these samples, could favor sulfur oxidation and prevent Rh–S interactions. Likewise, the theoretical calculations show that desorption of S–O species from Rh/CeO{sub 2} system is more favorable than that from Ni/CeO{sub 2} one. Therefore, our experimental and theoretical study about sulfur deactivation of Ni and Rh supported on CeO{sub 2} allow us to postulate that Rh can help to desorb SO{sub x} species formed on the support, retarding sulfur poisoning of the Rh/CeO{sub 2} catalysts. - Highlights: • CeO{sub 2} support can act as a sacrifice trap decreasing sulfur poisoning. • Theoretical calculations indicate an important nickel affinity with sulfur. • Rh would favor desorption of S–O species formed on the support. • The O{sup 2−} species present on the Rh–CeO{sub 2} sample favor sulfur removal.

  8. Easy peak tracking in CE-UV and CE-UV-ESI-MS by incorporating temperature-correlated mobility scaling

    DEFF Research Database (Denmark)

    Li, Bin; Petersen, Nickolaj Jacob; Andersen, Line Hvass;

    2013-01-01

    A simple data reconstruction technique in capillary electrophoresis - ultraviolet - electrospray ionization - mass spectrometry (CE-UV-ESI-MS) is presented to overcome the drift in mobilities caused by various factors compromising the reproducibility of such data, e.g. Joule heating effects...... and the variation in thermostatic control along the capillary, drift in electroosmotic flow (EOF) and the suction effect caused by the nebulizing gas in coaxial CE-MS interfaces. We present here a method to transform the traditional time-based electropherogram into the corresponding temperature-correlated mobility...... scale allowing tracking of analytes independent from capillary dimensions, electric field strengths, temperature control, and distance between the detectors. The main principle of this alignment is based on including the current in the mobility calculations and relating this to the initial electrical...

  9. Search for double beta decay of {sup 136}Ce and {sup 138}Ce with HPGe gamma detector

    Energy Technology Data Exchange (ETDEWEB)

    Belli, P. [INFN sezione Roma “Tor Vergata”, I-00133 Rome (Italy); Bernabei, R., E-mail: rita.bernabei@roma2.infn.it [INFN sezione Roma “Tor Vergata”, I-00133 Rome (Italy); Dipartimento di Fisica, Università di Roma “Tor Vergata”, I-00133 Rome (Italy); Boiko, R.S. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Cappella, F. [INFN sezione Roma, I-00185 Rome (Italy); Dipartimento di Fisica, Università di Roma “La Sapienza”, I-00185 Rome (Italy); Cerulli, R. [INFN, Laboratori Nazionali del Gran Sasso, I-67010 Assergi (AQ) (Italy); Danevich, F.A. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Incicchitti, A. [INFN sezione Roma, I-00185 Rome (Italy); Dipartimento di Fisica, Università di Roma “La Sapienza”, I-00185 Rome (Italy); Kropivyansky, B.N. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Laubenstein, M. [INFN, Laboratori Nazionali del Gran Sasso, I-67010 Assergi (AQ) (Italy); Poda, D.V. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Polischuk, O.G.; Tretyak, V.I. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); INFN sezione Roma, I-00185 Rome (Italy)

    2014-10-15

    Search for double β decay of {sup 136}Ce and {sup 138}Ce was realized with 732 g of deeply purified cerium oxide sample measured over 1900 h with the help of an ultra-low background HPGe γ detector with a volume of 465 cm{sup 3} at the STELLA facility of the Gran Sasso National Laboratories of the INFN (Italy). New improved half-life limits on double beta processes in the cerium isotopes were set at the level of lim⁡T{sub 1/2}∼10{sup 17}–10{sup 18} yr; many of them are even two orders of magnitude larger than the best previous results.

  10. Phase Equilibria and Magnetic Phases in the Ce-Fe-Co-B System

    Directory of Open Access Journals (Sweden)

    Tian Wang

    2016-12-01

    Full Text Available Ce-Fe-Co-B is a promising system for permanent magnets. A high-throughput screening method combining diffusion couples, key alloys, Scanning Electron Microscope/Wavelength Dispersive X-ray Spectroscope (SEM/WDS, and Magnetic Force Microscope (MFM is used in this research to understand the phase equilibria and to explore promising magnetic phases in this system. Three magnetic phases were detected and their homogeneity ranges were determined at 900 °C, which were presented by the formulae: Ce2Fe14−xCoxB (0 ≤ x ≤ 4.76, CeCo4−xFexB (0 ≤ x ≤ 3.18, and Ce3Co11−x FexB4 (0 ≤ x ≤ 6.66. The phase relations among the magnetic phases in this system have been studied. Ce2(Fe, Co14B appears to have stronger magnetization than Ce(Co, Fe4B and Ce3(Co, Fe11B4 from MFM analysis when comparing the magnetic interactions of selected key alloys. Also, a non-magnetic CeCo12−xFexB6 (0 ≤ x ≤ 8.74 phase was detected in this system. A boron-rich solid solution with Ce13FexCoyB45 (32 ≤ x ≤ 39, 3 ≤ y ≤ 10 chemical composition was also observed. However, the crystal structure of this phase could not be found in the literature. Moreover, ternary solid solutions ε1 (Ce2Fe17−xCox (0 ≤ x ≤ 12.35 and ε2 (Ce2Co17−xFex (0 ≤ x ≤ 3.57 were found to form between Ce2Fe17 and Ce2Co17 in the Ce-Fe-Co ternary system at 900 °C.

  11. Localized and mixed valence state of Ce 4 f in superconducting and ferromagnetic CeO1 -xFxBiS2 revealed by x-ray absorption and photoemission spectroscopy

    Science.gov (United States)

    Sugimoto, T.; Ootsuki, D.; Paris, E.; Iadecola, A.; Salome, M.; Schwier, E. F.; Iwasawa, H.; Shimada, K.; Asano, T.; Higashinaka, R.; Matsuda, T. D.; Aoki, Y.; Saini, N. L.; Mizokawa, T.

    2016-08-01

    We have performed Ce L3-edge x-ray absorption spectroscopy (XAS) and Ce 4 d -4 f resonant photoemission spectroscopy (PES) on single crystals of CeO1 -xFxBiS2 for x =0.0 and 0.5 in order to investigate the Ce 4 f electronic states. In Ce L3-edge XAS, a mixed valence of Ce was found in the x =0.0 sample, and F doping suppressed it, which is consistent with the results on polycrystalline samples. As for resonant PES, we found that the Ce 4 f electrons in both x =0.0 and 0.5 systems respectively formed a flat band at 1.0 and 1.4 eV below the Fermi level and there was no contribution to the Fermi surfaces. Interestingly, Ce valence in CeOBiS2 deviates from Ce3 + even though Ce 4 f electrons are localized, indicating the Ce valence is not in a typical valence fluctuation regime. We assume that localized Ce 4 f in CeOBiS2 is mixed with unoccupied Bi 6 pz , which is consistent with a previous local structural study. Based on the analysis of the Ce L3-edge XAS spectra using Anderson's impurity model calculation, we found that the transfer integral becomes smaller, increasing the number of Ce 4 f electrons upon the F substitution for O.

  12. Strategie vstupu společnosti Netflix na český trh

    OpenAIRE

    Do Hai, Linh

    2015-01-01

    Tato diplomová práce kriticky zkoumá analýzu vstupní strategie společnosti Netflix, který hodlá vstoupit na český trh, s cílem navrhnout vhodná doporučení. Práce obsahuje detailní analýzu společnosti a současného stavu trhu v České Republice. Kriticky přezkoumané teoretické rámce a aplikované analýzy jsou následně použity jako základ pro argumentaci a vyhodnocení problematiky strategie. Doporučení pro expanzi jsou poskytovány na základě vyhodnocených průzkumu a analýz. This diploma thesis ...

  13. Glass forming ability of the Al-Ce-Ni system; Avaliacao da capacidade de formacao vitrea do sistema Al-Ce-Ni

    Energy Technology Data Exchange (ETDEWEB)

    Triveno Rios, C. [Engenharia Mecanica, Universidade Federal de Mato Grosso, Rondonopolis, MT (Brazil)], e-mail: triveno@ufmt.br; Surinach, S.; Baro, M.D. [Departamento de Engenharia de Materiais - Universidade Federal de Sao Carlos, SP (Brazil); Bolfarini, C.; Botta, W.J.; Kiminami, C.S. [Departamento de Fisica da Universidade Autonoma de Barcelona, Bellaterra (Spain)

    2010-07-01

    In the present work, the glass forming ability (GFA) and its compositional dependence on Al-Ni-Ce system alloys were investigated in function of several thermal parameters. Rapidly quenched Al{sub 85}Ni{sub 15}-{sub X}Ce{sub X} (X=4,5,6,7,10), Al{sub 90}Ni{sub 5}Ce{sub 5}, Al{sub 89}Ni{sub 2}.{sub 4}Ce{sub 8}.{sub 6}, Al{sub 80}Ni{sub 15.6}Ce{sub 4}.{sub 4} and Al{sub 78}Ni{sub 18.5}Ce{sub 3.5} amorphous ribbons were produced by melt-spinning and the structural transformation during heating was studied using a combination of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The results showed that the GFA and the thermal stability in the Al-rich corner of Al- Ni-Ce system alloys were enhanced by increasing the solute content and specifically the Ce content (author)

  14. Preparation for CeO2/Nanographite Composite Materials and Electrochemical Degradation of Phenol by CeO2/Nanographite Cathodes.

    Science.gov (United States)

    Yu, Li; Yu, Xiujuan; Sun, Tianyi; Wang, Na

    2015-07-01

    CeO2/nanographite (CeO2/nano-G) composite materials were got by chemical precipitation method with nanographite (nano-G) and cerous nitrate hexahydrate as raw materials. The microstructures of CeO2/nano-G composite materials were characterized by means of SEM, XRD, XPS and Raman. The cathodes were made by nano-G and CeO2/nano-G composite materials, respectively. The electrolysis phenol was conducted by the diaphragm cell prepared cathode and the Ti/RuO2 anode. The results indicated that the Cerium oxide is mainly in nanoscale spherical state, uniformly dispersed in the nanographite sheet surface, and there are two different oxidation states for elemental Ce, namely, Ce(III) and Ce(IV). In the diaphragm electrolysis system with the aeration conditions, the degradation rate of phenol reached 93.9% under 120 min's electrolysis. Ceria in the cathode materials might lead to an increase in the local oxygen concentration, which accelerated the two-electron reduction of O2 to hydrogen peroxide (H2O2). The removal efficiency of phenol by using the CeO2/nano-G composite cathode was better than that of the nano-G cathode.

  15. Effects of CeO2 Nanoparticles on Terrestrial Isopod Porcellio scaber: Comparison of CeO2 Biological Potential with Other Nanoparticles.

    Science.gov (United States)

    Malev, Olga; Trebše, Polonca; Piecha, Małgorzata; Novak, Sara; Budič, Bojan; Dramićanin, Miroslav D; Drobne, Damjana

    2017-02-01

    Nano-sized cerium dioxide (CeO2) particles are emerging as an environmental issue due to their extensive use in automobile industries as fuel additives. Limited information is available on the potential toxicity of CeO2 nanoparticles (NPs) on terrestrial invertebrates through dietary exposure. In the present study, the toxic effects of CeO2 NPs on the model soil organism Porcellio scaber were evaluated. Nanotoxicity was assessed by monitoring the lipid peroxidation (LP) level and feeding rate after 14-days exposure to food amended with nano CeO2. The exposure concentration of 1000 μg of CeO2 NPs g(-1) dry weight food for 14 days significantly increased both the feeding rate and LP. Thus, this exposure dose is considered the lowest observed effect dose. At higher exposure doses of 2000 and 5000 μg of CeO2 NPs g(-1) dry weight food, NPs significantly decreased the feeding rate and increased the LP level. Comparative studies showed that CeO2 NPs are more biologically potent than TiO2 NPs, ZnO NPs, CuO NPs, CoFe2O4 NPs, and Ag NPs based on feeding rate using the same model organism and experimental setup. Based on comparative metal oxide NPs toxicities, the present results contribute to the knowledge related to the ecotoxicological effects of CeO2 NPs in terrestrial invertebrates exposed through feeding.

  16. Influence of hybridization in the Magnetic Circular X-ray Dichroism at the Ce-M4,5 absorption edges of Ce-Fe systems

    NARCIS (Netherlands)

    Finazzi, M.; de Groot, F.M.F.; Dias, A.-M.; Kappler, J.-P.; Schulte, O.; Felsch, W.; Krill, G.

    2013-01-01

    We have performed a Magnetic Circular X-ray Dichroism (XMCD) study at the Ce-M*,s absorption edges on some Ce-Fe systems. We find that the dichroism signal in these systems is very sensitive to the degree of hybridization of the 4f electrons with the valence band. XMCD is able to demonstrate that th

  17. Influence of hybridization in the magnetic circular X-ray dichroism at the Ce-M(4,5) absorption edges of Ce-Fe systems

    NARCIS (Netherlands)

    Finazzi, M; deGroot, FMF; Dias, AM; Kappler, JP; Schulte, O; Felsch, W; Krill, G

    1996-01-01

    We have performed a Magnetic Circular X-ray Dichroism (XMCD) study at the Ce-M(4,5) absorption edges on some Ce-Fe systems. We find that the dichroism signal in these systems is very sensitive to the degree of hybridization of the 4f electrons with the valence band. XMCD is able to demonstrate that

  18. EnTranCe to the second life of gas : EnTranCe as source of innovation and human resources

    NARCIS (Netherlands)

    Aué, Jan-jaap; Gemert, Wim van; Martinus, Gerard

    2015-01-01

    The living lab EnTranCe provides a platform for open innovations. Stakeholders from large industry, SME’s, government and the research community team up to work on the future of the European energy system, with gas in a pivotal role. An important element of the innovation strength of EnTranCe is tha

  19. Optical and scintillation properties of Ce3+ doped LiYF4 and LiLuF4 crystals

    NARCIS (Netherlands)

    Combes, CM; Dorenbos, P; vanEijk, CWE; Pedrini, C; DenHartog, HW; Gesland, JY; Rodnyi, PA

    1997-01-01

    Optical properties of LiYF4:Ce and LiLuF4:Ce were studied viz. optical absorption spectra and X-ray induced emission spectra. The scintillation characteristics of LiYF4:Ce and LiLuF4:Ce were investigated viz. gamma-ray induced pulse height spectra and decay time measurements. A model is presented to

  20. One-Pot Polyol Synthesis of Pt/CeO2 and Au/CeO2 Nanopowders as Catalysts for CO Oxidation.

    Science.gov (United States)

    Pilger, Frank; Testino, Andrea; Lucchini, Mattia Alberto; Kambolis, Anastasios; Tarik, Mohammed; El Kazzi, Mario; Arroyo, Yadira; Rossell, Marta D; Ludwig, Christian

    2015-05-01

    The facile one-pot synthesis of CeO2-based catalysts has been developed to prepare a relatively large amount of nanopowders with relevant catalytic activity towards CO oxidation. The method consists of a two-steps process carried out in ethylene glycol: in the first step, 5 nm well-crystallized pure CeO2 is prepared. In a subsequent second step, a salt of a noble metal is added to the CeO2 suspension and the deposition of the noble metal on the nanocrystalline CeO2 is induced by heating. Two catalysts were prepared: Pt/CeO2 and Au/CeO2. The as-prepared catalysts, the thermally treated catalysts, as well as the pure CeO2, are characterized by XRD, TGA, XPS, FTIR, HR-TEM, STEM, particle size distribution, and N2-physisorption. In spite of the identical preparation protocol, Au and Pt behave in a completely different way: Au forms rather large particles, most of them with triangular shape, easily identifiable and dispersed in the CeO2 matrix. In contrast, Pt was not identified as isolated particles. The high resolution X-ray diffraction carried out on the Pt/CeO2 thermally treated sample (500 degrees C for 1 h) shows a significant CeO2 lattice shrinkage, which can be interpreted as an at least partial incorporation of Pt into the CeO2 crystal lattice. Moreover, only Pt2+ and Pt4+ species were identified by XPS. In literature, the incorporation of Pt into the CeO2 lattice is supported by first-principle calculations and experimentally demonstrated only by combustion synthesis methods. To the best of our knowledge this is the first report where ionically dispersed Pt into the CeO2 lattice is obtained via a liquid synthesis method. The thermally treated Pt/CeO2 sample revealed good activity with 50% CO conversion at almost room temperature.

  1. 新矿物丁道衡矿-(Ce):珀硅钛铈矿的同质多象体和硅钛铈矿亚族C(1)位上的钛类似矿物%A NEW MINERAL,DINGDAOHENGITE-(Ce):THE POLYMORPH OF PERRIERITE-(Ce)AND A TITAMC ANALOG AT THE C(1)SITE OF CHEVKINITE SUB-GROUP

    Institute of Scientific and Technical Information of China (English)

    徐金沙; 杨光明; 李国武; 邬志亮; 沈敢富

    2008-01-01

    丁道衡矿-(Ce):(Ce,La)4Fe2+(Ti,Fe2+,Mg,Fe3+)2Ti2Si4O22,理想的结构化学式Ce2Ce2Fe2+Ti2Ti2Si4O22单斜晶系,α=1.34656(15)nm,b=0.57356(6)nm,c=1.10977(12)nm,β=100.636(2)°,V=0.84239(46)nm3,空间群P21/a(假C2/m),Z=2.作为硅钛铈矿(chevkinite)族矿物的新成员,它产于举世闻名的白云鄂博铁.稀土.铌矿床镁夕卡岩中,多数单晶体长0.2~1.0 cm,最大者长大于1.5 cm.共生矿物有透辉石、透闪石、钠透闪石、褐帘石-(Ce)、磁铁矿、尖晶石、烧绿石、氟金云母、氟磷灰石、石英和萤石等.矿物具有褐色条痕和半金属一金属光泽的黑色,其褐黑色碎片半透明.性脆、具有贝壳状断口、无解理和裂开.显微硬度(VHN25g)为606.0~717.4 kg/mm/12(相当于摩氏硬度约5.9).矿物实测密度4.83(7)g/cm3,计算密度值4.88(0)g/cm3.丁道衡矿-(ce)的反射色为带灰色的浅黄色,多色性为不同色调的灰色.平均反射率(λ=589nm)为11.4%~12.5%.矿物为二轴晶负光性.作过结构精测的丁道衡矿-(Ce)晶体的电子探针测值:SiO2:19.29,TiO2:18.26,A12O3:0.04,FeO:8.49,Fe2O3,:1.67,ThO2:0.16,MgO:1.32,CaO:2.17,Nb2O5:0.47,Ta2O5:0.00,La2O3:19.53,Ce2O3:28.08,Y2O3:0.00,Na1O:0.01,总量99.46%;其中Fe3+/Fe2+的比值依穆斯堡尔谱换算.根据结构精测每个单位分子式中O=22和C(1)位上Ti优先占位,计算的矿物晶体化学式为(Ce2.13,La1.49Ca0.48Th0 01)Σ4.11Fe2+(Tin0.88Fe2+0.47Mg0.41 Fe0.0)Σ2.03(Ti1.96Nb0 04)Σ2.00(Si2O7)2O3.分别用P21/a和C2/m对丁道衡矿-(Ce)的晶体结构作了精测.结果表明,丁道衡矿-(Ce)的真空间群是P20/a.换言之,它才是真正珀硅钛铈矿[perrierite-(Ce)]的同质多象体.显而易见,硅钛铈矿族矿物既可以有P21/a空间群,又可以有C2/m空间群.

  2. Simultaneous determination of scopolamine, hyoscyamine and anisodamine in in vitro growth media of selected Solanaceae hairy roots by CE method.

    Science.gov (United States)

    Dziomba, Szymon; Łepek, Teresa; Jaremicz, Zbigniew; Łuczkiewicz, Maria; Prahl, Adam; Kowalski, Piotr

    2015-09-15

    An electrophoretic method for fast separation of three tropane alkaloids (hyoscyamine, anisodamine and scopolamine) was presented. The substances were complete resolved in less than one minute due to utilization of relatively short capillary (20.2cm effective length) and high voltage (25kV). Detector probing frequency was found among the parameters that significantly affected the detection sensitivity. The performed experiments showed insufficient available probing frequency of used commercial spectrophotometric detector according to capillary electrophoresis (CE) separation potential. Under the optimized conditions the background electrolyte (BGE) was composed of 20mM Tris, 6mM HCl and 20mM NaCl (pH 8.50). All analyses were carried out in fused silica capillaries of 50μm (inner diameter) and 31.2cm (total capillary length). Samples were injected hydrodynamically (5s; 3.45kPa) without any sample preparation step and separation was performed at 25kV. The elaborated method was applied in plant cultures growth media analysis after incubation with hairy roots of selected Solanaceae species. The performed experiments proved the usefulness of CE in quality control of biotechnological processes.

  3. Enhancement of red to orange emission ratio of YPO4:Eu3+,Ce3+ and its dependence on Ce3+ concentration

    Institute of Scientific and Technical Information of China (English)

    ZHAN Shiping; GAO Yongyi; LIU Yunxin; ZHONG Hui

    2012-01-01

    Eu3+ and Ce3+ co-doped YPO4 microspheres were synthesized by hydrothermal method without template.The emission spectra showed that the red emission centered at 618 nm could be readily increased relatively to the orange emission centered at 590 nm by controlling the doping concentration of Ce3+ ion.The investigation based on excitation spectra and decay curves demonstrated that the doped Ce3+ ions took two efficient energy transfers to Eu3+ ions and affected the lifetime of the emission states ofEu3+ ions so that the emission spectra of Eu3+ ion were accordingly tuned with the Ce3+ content increasing.This controllable red (5D0→7F2) to orange (5D0→7F1) emission ratio of YPO4:Eu3+,Ce3+ made it very promising for encoded anti-fake labels and bio-labels.

  4. Effect of Ce addition on the surface properties and n-dodecane dehydrogenation performance of Pt-Sn/Ce-Al2O3 catalyst

    Science.gov (United States)

    Li, Xianru; He, Songbo; Wei, Huangzhao; Luo, Sha; Gu, Bin; Sun, Chenglin

    2015-08-01

    Ce-modified alumina carriers with different Ce content were prepared by vacuum isovolume impregnation method aiming to improve the n-dodecane catalytic dehydrogenation performance of PtSn/Al2O3 catalyst. The support and catalyst were characterized by XRD, N2 adsorption-desorption, NH3-TPD, H2-TPR, CO-pulse adsorption and TG-DTG. Results showed that Ce addition decreased the surface acid amount significantly and inhibited the reduction of SnO x species. Besides, Ce containing catalyst showed higher n-dodecane dehydrogenation activity and stability and lower coke deposition amount and coke burning temperature. In our study, the optimal Ce addition amount for n-dodecane dehydrogenation was 2%.

  5. Thermodynamic Assessment of the ZrO2-CeO2 and ZrO2-CeO1.5 Binary System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An optimal set of thermodynamic parameters of the ZrO2-CeO1.5 system has been obtained using phase diagram data by modern CALPHAD (CALculation of PHAse Diagrams) technique. The liquid and other solid solution phases were regarded as substitutional solution. The ordered Zr2Ce2O7 phase was treated as a stoichiometric compound. The ZrO2-CeO2 system has been re-optimized with new reference state. A comparison between the ZrO2-CeO2 system and ZrO2-CeO1.5 system has been made through calculation. With the calculation, the experimental information is well reproduced and a good agreement is obtained.

  6. Single-Crystalline CeOHCO3 with Rhombic Morphology:Synthesis and Thermal Conversion to CeO2%单晶菱形CeOHCO3片状物的制备及其向CeO2的热转换

    Institute of Scientific and Technical Information of China (English)

    张泽芳; 俞磊; 刘卫丽; 宋志棠

    2011-01-01

    Single-crystalline CeOHCO3 rhombic micro-plates with an orthorhombic structure were synthesized by the precipitation reaction between (NH4)2Ce(NO3)6 and CO(NH)2 in the presence of 3-aminopropyltriethoxysilane (APS). Polycrystalline CeO2 rhombic micro-plates were prepared by thermal decomposition of single-crystalline CeOHCO3 rhombic micro-plates at 600 ℃ in air. CeOHCO3 and CeO2 rhombic micro-plates were characterized by XRD, filed-emission scanning electron microscopy (FESEM), TEM, and XPS. The results indicate that APS plays an important role in the preparation of single-crystalline CeOHCO3 rhombic micro-plates because the CeO2 is produced without APS. In addition, the rhombic shape of the products is not ruined apparently by the thermal conversion process from CeOHCO3 to CeO2.%以硝酸铈铵和尿素为反应物,γ-氨丙基三乙氧基硅烷(KH550)为助剂,通过沉淀反应制得了单晶菱形CeOHCO3片状物.然后将CeOHCO3在600℃空气气氛中灼烧获得了菱形CeO2.通过XRD和SEM对反应物中是否含有KH550助剂所得的产物进行了分析,结果发现只有含有KH550才能获得菱形CeOHCO3片状物,并且在灼烧过程中产物的形貌仍保持菱形.然后采用TEM对菱形CeOHCO3和CeO2进行了表征,结果发现CeOHCO3为单晶产物而灼烧后所得的CeO2为多晶产物.

  7. Ce4Ag3Ge4O(0.5)--chains of oxygen-centered [OCe2Ce(2/2)] tetrahedra embedded in a [CeAg3Ge4] intermetallic matrix.

    Science.gov (United States)

    Heymann, Gunter; Riecken, Jan F; Johrendt, Dirk; Rayaprol, Sudhindra; Pöttgen, Rainer; Huppertz, Hubert

    2013-11-14

    The oxidation of an intermetallic phase under high-pressure/high-temperature conditions led to the synthesis of Ce4Ag3Ge4O(0.5) exhibiting [OCe2Ce(2/2] tetrahedral chains, in which the oxygen atoms statistically occupy the tetrahedral centres. Starting from a 1:1:1 CeAgGe precursor (NdPtSb type), a multianvil high-pressure/high-temperature experiment at 11.5 GPa and 1250-1300 °C revealed Ce4Ag3Ge4O(0.5), crystallizing in the space group Pnma with the following lattice parameters: a = 2087.3(4), b = 439.9(1), and c = 1113.8(2) pm. Magnetic measurements showed Curie-Weiss behavior above 100 K with an experimental magnetic moment of 2.42 µB per Ce atom, close to the value for the free Ce(3+) ion, clearly indicating trivalent cerium in Ce4Ag3Ge4O(0.5). Full potential GGA+U band structure calculations resulted in metallic properties and a magnetic ground state with one unpaired 4f-electron per cerium in agreement with the experiments.

  8. Thermoelectric transport properties of nanostructured FeSb 2 and Ce-based heavy-fermions CeCu and CeAl 3

    Science.gov (United States)

    Pokharel, Mani R.

    Thermoelectric (TE) energy conversion is an all-solid-state technology which can convert waste thermal energy into useful electric power and cool ambience without using harmful gases like CFC. Due to their several advantages over traditional energy conversion technologies, thermoelectric generators (TEG) and coolers (TEC) have drawn enormous research efforts. The objective of this work is to find promising materials for thermoelectric cooling applications and optimize their thermoelectric performances. Finding a material with a good value for the thermoelectric figure-of-merit (ZT) at cryogenic temperatures, specifically below 77 K, has been of great interest. This work demonstrates that FeSb2 1, CeCu6 2 and CeAl3 3, all belonging to a class of materials with strongly correlated electron behavior; exhibit promising thermoelectric properties below 77 K. In general, ZT of a TE material can be increased using two basic approaches: lattice thermal conductivity reduction and power factor (PF) enhancement. The results of this study indicate that nanostructuring effectively decreases the thermal conductivity of FeSb2, CeCu6 and CeAl 3 leading to improved ZT. The approach of introducing point-defect scattering to further reduce the thermal conductivity is successfully implemented for Te-substituted FeSb2 nanostructured samples 4. A semiconductor/metal interface has long been proposed to exhibit enhanced thermoelectric properties. We use this technique by introducing Ag-nanoparticles in the host FeSb2 which further increases ZT by 70% 5. Additionally, a detailed investigation is made on the phonon-drag effect as a possible mechanism responsible for the large value of the Seebeck coefficient of FeSb2 6. We show that the phonon-drag mechanism contributes significantly to the large Seebeck effect in FeSb2 and hence this effect cannot be minor as was proposed in literatures previously. A model based on Kapitza-resistance and effective medium approach (EMA) is used to analyze

  9. Scintillation and optical properties of Ce-doped YAGG transparent ceramics

    Institute of Scientific and Technical Information of China (English)

    Masaki Mori; Jian Xu; Go Okada; Takayuki Yanagida; Jumpei Ueda; Setsuhisa Tanabe

    2016-01-01

    We investigated photoluminescence (PL) and scintillation properties of Ce3+-doped Y3Al2Ga3O12 (Ce:YAGG) trans-parent ceramics synthesized by vacuum sintering with different Ce3+ concentrations (mol.%) from 0.3% to 1% (0.3%Ce:YAGG, 0.5%Ce:YAGG, 0.8%Ce:YAGG and 1%Ce:YAGG). The samples were synthesized by the vacuum sintering technique. The obtained samples showed a very strong and broad PL emission by the 5d1-4f transition of Ce3+in the wavelength range from 470 to 600 nm. The PL decay profiles were approximated by a single exponential decay function with the time constants of around 33–39 ns. Fur-thermore, the scintillation spectra induced by X-rays showed similar features with those observed in PL. The scintillation decay time profiles followed a second-order exponential decay function. The fast component group (ranged 35–42 ns) were dominantly contrib-uted by the 5d1-4f transition of Ce3+. The pulse height spectra utilizing the latter emissions showed a clear photoabsorption peak. Among those samples tested, 0.5%Ce:YAGG sample showed the highest scintillation light yield of 21,400 ph/MeV under 137Csγ-ray irradiation.

  10. Origin of enhanced photocatalytic activity of F-doped CeO2 nanocubes

    Science.gov (United States)

    Miao, Hui; Huang, Gui-Fang; Liu, Jin-Hua; Zhou, Bing-Xin; Pan, Anlian; Huang, Wei-Qing; Huang, Guo-Fang

    2016-05-01

    CeO2 nanoparticles are synthesized using a low-temperature solution combustion method and subsequent heat treatment in air. It is found that F-doping leads to smaller particle size and the formation of CeO2 nanocubes with higher percentage of reactive facets exposed. The band gap is estimated to be 3.16 eV and 2.88 eV, for pure CeO2 and fluorine doped CeO2 (F-doped CeO2) nanocubes, respectively. The synthesized F-doped CeO2 nanocubes exhibit much higher photocatalytic activities than commercial TiO2 and spherical CeO2 for the degradation of MB dye under UV and visible light irradiation. The apparent reaction rate constant k of MB decomposition over the optimized F-doped CeO2 nanocubes is 9.5 times higher than that of pure CeO2 and 2.2 times higher than that of commercial TiO2. The enhanced photocatalytic activity of F-doped CeO2 nanocubes originates from the fact that F-doping induces the small size, the highly reactive facets exposed, the intense absorption in the UV-vis range and the narrowing of the band gap. This research provides some new insights for the synthesis of the doping of the foreign atoms into photocatalyst with controlled morphology and enhanced photocatalytic activity.

  11. CeOHCO3和CeO2束状纳米结构的制备及表征%Preparation and Characterization of Crystalline CeOHCO3 and CeO2 with Bundle-like Nanostructures

    Institute of Scientific and Technical Information of China (English)

    张晓娟; 张胜义; 田玉鹏; 金葆康; 吴杰颖

    2008-01-01

    The cantaloupe-like particles of CeOHCO3 were synthesized in aqueous solution by using cetyhrimethylammonium bromide (CTAB) as soft template. Then, the bunchiness rods of CeO2 were obtained by calcining CeOHCO3 at 450 ℃. The results of thermogravimetric/differential thermal analysis reveal that an endothermic reaction with decomposition is involved in the transformation process from CeOHCO3 to CeO2. By scanning electron microscopy and X-ray diffraction analysis, it is found that the orthorhombic phase CeOHCO3 particles are constituted of short nanorods with diameters ranging from several tens nm to over 100 nm, and the cubic phase CeO2 rods are composed of small particles with diameter ca. 15 nm. From the results of UV-Vis absorption and photoluminescence analysis, it is found that the CeO2 possess abundant defects, and the band gaps of the CeO2 and CeOHCO3 are ca. 2.70 eV and 3.87 eV, respectively.

  12. Microstructures and mechanical properties in B{sub 4}C-CeO{sub 2} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sun Shuchen, E-mail: sunsc@smm.neu.edu.cn [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Sakamoto, Tatsuaki; Nakai, Kiyomichi [Department of Materials Science and Biotechnology, Ehime University, 3Bunkyo-cho, Matsuyama 790-8577 (Japan); Kurishita, Hiroaki [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Kobayashi, Sengo [Department of Materials Science and Biotechnology, Ehime University, 3Bunkyo-cho, Matsuyama 790-8577 (Japan); Xu Jingyu; Cao Hui; Gao Bo; Bianxue; Wu Wenyuan; Tu Ganfeng [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Matsuda, Seiji [Department of Anatomy and Embryology, Ehime University, Shizugawa, Toon 791-0295 (Japan)

    2011-10-01

    B{sub 4}C-CeO{sub 2} composite ceramics with various concentrations of CeO{sub 2} were fabricated by hot press. The effects of CeO{sub 2} on the microstructures and mechanical properties of the B{sub 4}C-CeO{sub 2} ceramics have been investigated. During hot press, CeB{sub 6} was formed by the reaction between CeO{sub 2} and B{sub 4}C. The B{sub 4}C-CeO{sub 2} ceramics had higher levels of density, fracture toughness, flexural strength and Vickers hardness than those in monolithic B{sub 4}C. The microstructures of the B{sub 4}C-CeO{sub 2} ceramics were observed and analyzed by transmission electron microscopy. In-situ synthesized CeB{sub 6} indicated whisker-like shape and grew along the interface with B{sub 4}C, and different boron carbides with different content of C existed at/around the interface of CeB{sub 6} with B{sub 4}C in the composite ceramics. It made mechanical properties greatly improved.

  13. The scintillation mechanism in LaCl sub 3 :Ce sup 3 sup +

    CERN Document Server

    Loef, E; Eijk, C W E

    2003-01-01

    The scintillation properties of LaCl sub 3 crystals, doped with Ce sup 3 sup + concentrations of 0.57, 1.0, 2.0, 4.0, and 10%, are studied under x-ray and gamma-quanta excitation at various temperatures. Under x-ray excitation, characteristic doublet Ce sup 3 sup + emission is observed with a maximum at 3.7 eV. Also self-trapped exciton (STE) emission is observed with a maximum near 3.1 eV. The contribution of STE luminescence to the total light yield decreases with increasing Ce concentration. For LaCl sub 3 :0.57%Ce sup 3 sup + , the contribution is 33%, whereas for LaCl sub 3 :10%Ce sup 3 sup + it is 4%. The total light yield of the Ce sup 3 sup + -doped samples ranges from 38 000 photons per megaelectronvolt (ph MeV sup - sup 1) of absorbed gamma-ray energy to 47 000(ph MeV sup - sup 1) for LaCl sub 3 :0.57%Ce sup 3 sup + and LaCl sub 3 :10%Ce sup 3 sup + , respectively. A model is proposed to explain the energy transfer from the host lattice to the Ce sup 3 sup + ions. At these Ce concentrations, energy ...

  14. Chemical interaction of Ce-Fe mixed oxides for methane selective oxidation

    Institute of Scientific and Technical Information of China (English)

    祝星; 杜云鹏; 王华; 魏永刚; 李孔斋; 孙令玥

    2014-01-01

    Chemical interaction of Ce-Fe mixed oxides was investigated in methane selective oxidation via methane temperature pro-grammed reduction and methane isothermal reaction tests over Ce-Fe oxygen carriers. In methane temperature programmed reduction test, Ce-Fe oxide behaved complete oxidation at the lower temperature and selective oxidation at higher temperatures. Ce-Fe mixed oxides with the Fe content in the range of 0.1-0.5 was able to produce syngas with high selectivity in high-temperature range (800-900 °C), and a higher Fe amount over 0.5 seemed to depress the CO formation. In isothermal reaction, complete oxidation oc-curred at beginning following with selective oxidation later. Ce1-xFexO2-δ oxygen carriers (x≤0.5) were proved to be suitable for the selective oxidation of methane. Ce-Fe mixed oxides had the well-pleasing reducibility with high oxygen releasing rate and CO selec-tivity due to the interaction between Ce and Fe species. Strong chemical interaction of Ce-Fe mixed oxides originated from both Fe* activated CeO2 and Ce3+ activated iron oxides (FeOm), and those chemical interaction greatly enhanced the oxygen mobility and se-lectivity.

  15. Catalytic reforming of toluene as tar model compound: effect of Ce and Ce-Mg promoter using Ni/olivine catalyst.

    Science.gov (United States)

    Zhang, Ruiqin; Wang, Huajian; Hou, Xiaoxue

    2014-02-01

    Tar produced by biomass gasification as a route of renewable energy must be removed before the gas can be used. This study was undertaken using toluene as a model tar compound for evaluating its steam reforming conversion with three Ni-based catalysts, Ni/olivine, Ni-Ce/olivine and Ni-Ce-Mg/olivine. Effects of Ce and Mg promoters on the reaction activity and coke deposition were studied. Overall the performance of Ce and Mg promoted Ni/olivine catalysts is better than that of only Ce promoter and Ni/olivine alone. The experimental results indicate that Ni-Ce-Mg/olivine catalysts could improve the resistance to carbon deposition, enhance energy gases yield and resist 10ppm H2S poison at 100mLmin(-1) for up to 400min. Furthermore, the activity of catalysts was related to the steam/carbon (S/C) ratios; at S/C ratio=5, T=790°C, space velocity=782h(-1) and t=2h, the Ni-Ce-Mg/olivine system yielded 89% toluene conversion, 5.6Lh(-1) product gas rate, 62.6mol% H2 content and 10% (mol useful gas mol(-1) toluene) energy yield. Moreover, at low S/C ratio, it had higher reaction activity and better ability to prevent coking. There is a small amount of carbon deposition in the form of amorphous carbon after 7h. Various characterization techniques such as XRD, FTIR and thermogravimetric were performed to investigate the coke deposition of Ni/olivine, Ni-Ce/olivine and Ni-Ce-Mg/olivine. It is suggested that 3% Ni-1% Ce-1% Mg/olivine was the most promising catalyst due to its minimum coke amount and the lower activation energy of coke burning.

  16. Manipulating Ce Valence in RE2Fe14B Tetragonal Compounds by La-Ce Co-doping: Resultant Crystallographic and Magnetic Anomaly.

    Science.gov (United States)

    Jin, Jiaying; Zhang, Yujing; Bai, Guohua; Qian, Zeyu; Wu, Chen; Ma, Tianyu; Shen, Baogen; Yan, Mi

    2016-07-26

    Abundant and low-cost Ce has attracted considerable interest as a prospective alternative for those critically relied Nd/Pr/Dy/Tb in the 2:14:1-type permanent magnets. The (Nd, Ce)2Fe14B compound with inferior intrinsic magnetic properties to Nd2Fe14B, however, cannot provide an equivalent magnetic performance. Since Ce valence is sensitive to local steric environment, manipulating it towards the favorable trivalent state provides a way to enhance the magnetic properties. Here we report that such a desirable Ce valence can be induced by La-Ce co-doping into [(Pr, Nd)1-x(La, Ce)x]2.14Fe14B (0 ≤ x ≤ 0.5) compounds via strip casting. As verified by X-ray photoelectron spectroscopy results, Ce valence shifts towards the magnetically favorable Ce(3+) state in the composition range of x > 0.3, owing to the co-doping of large radius La(3+) into 2:14:1 phase lattice. As a result, both crystallographic and magnetic anomalies are observed in the same vicinity of x = 0.3, above which lattice parameters a and c, and saturation magnetization Ms increase simultaneously. Over the whole doping range, 2:14:1 tetragonal structure forms and keeps stable even at 1250 K. This finding may shed light on obtaining a favorable Ce valence via La-Ce co-doping, thus maintaining the intrinsic magnetic properties of 2:14:1-type permanent magnets.

  17. Oxidative carbonylation of phenol with a Pd-O/CeO2-nanotube catalyst

    Institute of Scientific and Technical Information of China (English)

    Ye Yuan; Zhimiao Wang; Hualiang An; Wei Xue; Yanji Wang

    2015-01-01

    CeO2 nanotubes (CeO2-NT) were synthesized using carbon nanotubes as template by a liquid phase deposition and hydrothermal method. X-ray diffraction, transmission electron microscopy, and N2 adsorption-desorption were used to characterize the CeO2-NT. The wall of CeO2-NT was composed of small interconnected nanocrystallites ranging from 4 to 9 nm in size. The specific surface area of CeO2-NT was 108.8 m2/g with an outer diameter of 25 nm and length > 300 nm. Supported Pd cata-lyst, Pd-O/CeO2-NT, was prepared using CeO2-NT as the support. Temperature-programmed reduc-tion analysis showed that the surface oxygen on Pd-O/CeO2-NT could be reduced at low tempera-ture, therefore it showed high activity in the reaction. Pd-O/CeO2-NT was used as the catalyst for the oxidative carbonylation of phenol. It has better activity and DPC selectivity than Pd-O/CeO2-P, which was prepared by supporting Pd on zero dimensional CeO2particles. Under the optimized conditions, phenol conversion was 67.7% with 93.3% DPC selectivity with Pd-O/CeO2-NT. However, its catalyt-ic activity decreased when the catalyst was used for the second time. This was attributed to the destruction of the tubular structure of Pd-O/CeO2-NT and Pd leaching during the reaction.

  18. Mesoporous CeTiSiMCM-48 as novel photocatalyst for degradation of organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Mureseanu, Mihaela, E-mail: mihaela_mure@yahoo.com [Faculty of Chemistry, University of Craiova, 107 I Calea Bucureşti, 200478 Craiova (Romania); Parvulescu, Viorica, E-mail: vpirvulescu@icf.ro [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Radu, Teodora, E-mail: teocluj@gmail.com [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Street, 400293 Cluj Napoca (Romania); Institute of Interdisciplinary Research in Bio-Nano-Sciences, Babes Bolyai University, 400271 Cluj-Napoca (Romania); Filip, Mihaela [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Carja, Gabriela, E-mail: carja@uaic.ro [Faculty of Chemical Engineering and Environmental Protection, Technical University of Iasi, 71 D. Mangeron, Iasi (Romania)

    2015-11-05

    This work presents novel photocatalysts containing Ti and/or Ce embedded in the mesoporous silica framework (TiSiMCM-48, CeSiMCM-48 and CeTiSiMCM-48) that were prepared via a facile sol–gel process in the presence of ionic structure directing agents. The structural properties of the obtained materials were analyzed by X-ray diffraction (XRD), nitrogen adsorption-desorption, scanning and transmission electron microscopy (SEM, TEM), EDAX analysis, X-ray photoelectron microscopy (XPS), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS) and Fourier transformation infrared spectroscopy (FT-IR). The results indicated that Ce and Ti were highly dispersed or incorporated into the framework of the cubic SiMCM-48, with an enhanced light-trapping effect both in the UV and Vis regions. When applied to the photocatalytic degradation of phenol, the best results were obtained for the bimetallic hybrid. The best activity of CeTiSiMCM-48 photocatalyst was ascribed to improved electron–hole pair separation efficiency and formation of more reactive oxygen species due to the presence of Ce{sup 4+}/Ce{sup 3+}. The mesoporous support increases the dispersability of the photoactive Ti{sup 4+} or Ce{sup 4+}/Ce{sup 3+} species on the catalyst surface and the accessibility of the substrate to the active sites. Furthermore, the catalysts can be easily recovered and reused for four cycles without significant loss of activity. - Highlights: • Novel photocatalysts containing Ti and/or Ce embedded in the mesoporous MCM-48 silica. • Ce{sup 4+}/Ce{sup 3+} improved electron–hole pair separation and reactivity of oxygen species. • The mesoporous support increases the dispersability of the photoactive species. • The photocatalyst was highly active and stable for phenol degradation under UV irradiation. • TiCeSiMCM-48 can be recycled up to four cycles without significant loss of activity.

  19. Synthesis, characterization, and ecotoxicity of CeO2 nanoparticles with differing properties

    Science.gov (United States)

    Alam, Bushra; Philippe, Allan; Rosenfeldt, Ricki R.; Seitz, Frank; Dey, Sonal; Bundschuh, Mirco; Schaumann, Gabriele E.; Brenner, Sara A.

    2016-10-01

    CeO2 nanoparticles with various characteristics find an increasing number of applications in the electronic, medical, and other industries and are therefore likely released in the environment. This calls for investigations linking the physicochemical properties of these particles with their potential environmental impacts. In this study, CeO2 nanoparticle powders were prepared using three different precursors [Ce(NO3)3, CeCl3, and Ce(CH3COO)3] and annealing temperatures (300, 500, and 700 °C). This procedure resulted in nine different types of nanoparticles with differing size (5-90 nm), morphology, surface Ce3+/Ce4+ ratio, and slightly different crystal structures as characterized using transmission electron microscopy, dynamic light scattering, X-ray photoelectron spectroscopy, and X-ray diffraction measurements with Rietveld refinement. These CeO2 nanoparticles underwent toxicity testing at concentrations up to 64 mg L-1 using Daphnia magna. Toxic effects were observed for three particle types with EC50 values between 5 and 64 mg L-1. No clear correlation was observed between the physicochemical properties (size, shape, oxygen occupancy, Ce3+/Ce4+ ratio) of the nanoparticles and their toxicity. However, toxicity was correlated with the amount of Ce remaining suspended in the test medium after 24 h. This indicated that toxic effects may depend on the colloidal stability of CeO2 nanoparticles during the first day of exposure. Therefore, being readily suspended and remaining stable for several days in the aquatic media increases the likelihood that CeO2 nanoparticles will cause unwanted adverse effects.

  20. Hydrothermal synthesis of hexagonal CeO{sub 2} nanosheets and their room temperature ferromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Fanming, E-mail: mrmeng@ahu.edu.cn [School of Physics and Materials Science, Anhui University, Hefei 230601 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Zhang, Cheng; Fan, Zhenghua; Gong, Jinfeng; Li, Aixia; Ding, Zongling; Tang, Huaibao; Zhang, Miao; Wu, Guifang [School of Physics and Materials Science, Anhui University, Hefei 230601 (China)

    2015-10-25

    Hexagonal CeO{sub 2} nanosheets of 40–50 nm in thickness and 300–400 nm in side-length have been successfully synthesized via controlling the morphology of CeCO{sub 3}OH precursors by a facile hydrothermal technique using CeCl{sub 3}·7H{sub 2}O as cerium source, ammonium hydrogen carbonate as precipitants, and ethylenediamine as complexant. The reaction time and the amount of CeCl{sub 3}·7H{sub 2}O and ethylenediamine were systematically investigated. The as-synthesized hexagonal CeO{sub 2} nanosheets were examined by XRD, SEM, TEM, XPS, Raman scattering and magnetization measurements. It is found that the amount of CeCl{sub 3}·7H{sub 2}O and ethylenediamine are key parameters for controlling the final morphology. The hexagonal CeO{sub 2} nanosheets have a fluorite cubic structure and there are Ce{sup 3+} ions and oxygen vacancies in surface of samples. The synthesized CeO{sub 2} shows excellent room temperature optical properties. M–H curve exhibits excellent room-temperature ferromagnetism (RTFM) with saturation magnetization (M{sub s}) of 3.02 × 10{sup −2} emu/g, residual magnetization (M{sub r}) of 0.68 × 10{sup −2} emu/g and coercivity (H{sub c}) of 210 Oe, which is likely attributed to the effects of the Ce{sup 3+} ions and oxygen vacancies. - Highlights: • Hexagonal CeO{sub 2} nanosheets with superexerllent RTFM are synthesized by a facile hydrothermal method. • RTFM mechanism of CeO{sub 2} nanosheets can be attributed to the influences of oxygen vacancies and Ce{sup 3+} ions. • A defect driven dissolution–recrystallization mechanism is suggested to explain the transformation from nanowires to nanosheets.

  1. Desafios da operacionalização do Método da Roda: experiência em Sobral (CE

    Directory of Open Access Journals (Sweden)

    Hermínia Maria Sousa da Ponte

    Full Text Available O texto discorre sobre os atuais desafios institucionais da operacionalização do Método da Roda, tendo como cenário o Sistema Municipal de Saúde de Sobral (CE. Considera-se que as Rodas representam possibilidade de construção de espaços coletivos e de constituição de sujeitos, com capacidade de análise e de intervenção como estratégias de democracia institucional. Na sua operacionalidade, ficou evidente o predomínio da dimensão administrativa, em detrimento da pedagógica, da política e da terapêutica. Os trabalhadores expressaram pouco engajamento político e afetivo, o que tem sido realizado em uma relação demanda-execução, com absenteísmo de algumas categorias profissionais.

  2. Separation of Ce and La from Synthetic Chloride Leach Solution of Monazite Sand by Precipitation and Solvent Extraction

    Science.gov (United States)

    Banda, Raju; Jeon, Ho Seok; Lee, Man Seung

    2014-12-01

    Precipitation and solvent extraction experiments have been performed to recover light rare earths from simulated monazite sand chloride leach solutions. Precipitation conditions were obtained to recover Ce by adding NaClO as an oxidant. Among some cationic extractants (PC 88A, D2EHPA, Cyanex 272, LIX 63), PC 88A showed the best performance to separate La from the resulting chloride solution. Furthermore, the mixture of PC 88A with other solvating (TBP, TOPO) and amine extractants (Alamine 336, Aliquat 336) was tested to increase the separation factor of La from Pr and Nd. The use of mixed extractants greatly enhanced the separation of La from the two other metals. McCabe-Thiele diagrams for the extraction of Pr and Nd with the PC 88A/Alamine 336 mixture were constructed.

  3. Ground tests with prototype of CeBr3 active gamma ray spectrometer proposed for future venus surface missions

    Science.gov (United States)

    Litvak, M. L.; Sanin, A. B.; Golovin, D. V.; Jun, I.; Mitrofanov, I. G.; Shvetsov, V. N.; Timoshenko, G. N.; Vostrukhin, A. A.

    2017-03-01

    The results of a series of ground tests with a prototype of an active gamma-ray spectrometer based on a new generation of scintillation crystal (CeBr3) are presented together with a consideration to its applicability to future Venus landing missions. We evaluated the instrument's capability to distinguish the subsurface elemental composition of primary rock forming elements such as O, Na, Mg, Al, Si, K and Fe. Our study uses heritage from previous ground and field tests and applies to the analysis of gamma lines from activation reaction products generated by a pulsed neutron generator. We have estimated that the expected accuracies achieved in this approach could be as high as 1-10% for the particular chemical element being studied.

  4. Response of Cs2LiYCl6:Ce (CLYC) to High Energy Protons

    Energy Technology Data Exchange (ETDEWEB)

    Coupland, Daniel David Schechtman [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stonehill, Laura Catherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Goett III, John Jerome [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-23

    Cs2LiYCl6:Ce (CLYC) is a promising new inorganic scintillator for gamma and neutron detection. As a gamma-ray detector, it exhibits bright light output and better resolution and proportionality of response than traditional gamma-ray scintillators such as NaI. It is also highly sensitive to thermal neutrons through capture on 6Li, and recent experiments have demonstrated sensitivity to fast neutrons through interactions with 35Cl. The response of CLYC to other forms of radiation has not been reported. We have performed the first measurements of the response of CLYC to several-hundred MeV protons. We have collected digitized waveforms from proton events, and compare to those produced by gammas and thermal neutrons. Finally, we discuss the potential for pulse shape discrimination between them.

  5. At NA2

    CERN Multimedia

    1977-01-01

    One of the NA2 calorimeter sections is moved in. The NA2 calorimeter was divided in two halves, to the left and the right of the beam, each half consisting of sheets of passive high Z material interleaved with blades of plastic scintillators. The photo shows on the right, the upstream 'electron' module with eleven lead plates for a total radiation length of 20.

  6. Avaliação farmacognostica e da rotulagem das drogas vegetais boldo-do-chile (Peumus boldus Molina) e camomila (Matricaria recutita L.) comercializadas em Fortaleza, CE

    OpenAIRE

    F.P. SOARES; N.M. FREIRE; SOUZA, T. R. de

    2015-01-01

    RESUMO Boldo-do-chile (Peumus boldus) e camomila (Matricaria recutita) são plantas empregadas na fitoterapia principalmente para o tratamento de desordens hepáticas e intestinais, atuando também como anti-inflamatório e antiespasmódico, respectivamente. Por isso, o presente trabalho objetivou avaliar a qualidade farmacognostica dessas drogas vegetais comercializadas em Fortaleza (CE), além das informações de suas rotulagens. Quarenta e duas amostras de boldo, e quarenta e cinco amostras de ca...

  7. Ce isotope systematics of island arc lavas from the Lesser Antilles

    Science.gov (United States)

    Bellot, Nina; Boyet, Maud; Doucelance, Régis; Pin, Christian; Chauvel, Catherine; Auclair, Delphine

    2015-11-01

    The La-Ce systematics has one of the longest half-lifes (T1/2 = 292.5 Ga) of radioactive decay systems used in isotope geochemistry. Variations of the 138Ce/142Ce ratio are expected to be small and the use of Ce as isotopic tracer requires a very precise measurement. Compared to Sm-Nd studies, the La-Ce decay system can provide additional information about the nature of sediments recycled in subduction zones, because unusually large Ce anomalies relative to the neighboring rare earth elements exist in marine sediments such as fish teeth or hydrothermal deposits. Here, we present a chemical purification technique for Ce, and mass spectrometric technique to perform accurate and reproducible analyses of Ce isotopes of natural samples. We report a large set of Ce isotope data including analysis of 2 Ce reference material solutions (AMES and JMC-304), 2 rock standards (BCR-2 and BHVO-2), 2 chondrites (the carbonaceous chondrite Allende and the enstatite chondrite Sahara 97072), 4 mid-ocean ridge basalts, 30 arc lavas from the Martinique Island and 5 oceanic sediments from DSDP-site 144 drilled on the Demerara rise. The long-term, external precision obtained on the AMES reference material is 80 ppm (2 s.d., 138Ce/142Ce = 0.0225732 ± 18, n = 89). However, we note an evolution of isotopic ratios measured in static mode over the duration of this study (33 months). When the reproducibility is calculated from the AMES reference material measured during the same analytical session, it averages 40 ppm. All the 138Ce/142Ce ratios have been normalized to the AMES value of 0.0225746 (measured in session 7, 2 s.d. = 14 ppm, n = 8), a session during which the chondritic value has been defined and the peak tailing was negligible. The 138Ce/142Ce ratio measured for the JMC-304 Ce reference reagent is 0.0225706 ± 9 (2 s.d. = 38 ppm, n = 10). The analytical precision on natural samples is improved by a factor of about 4 in relation to previous studies on island arcs (Tanaka et al

  8. Vliv sociálních sítí na komunikaci a kulturu

    OpenAIRE

    Havlíček, Lukáš

    2015-01-01

    Má bakalářská práce je zaměřena na problematiku sociálních sítí a jejich vliv na dnešní společnost. Zabývá se jejich historií od prvotních pokusů až po nejnovější globální sociání sítě. Poté práce vysvětluje základní myšlenku vedoucí k vytvoření sociálních sítí i jejich charakteristické znaky. Dále nastiňuje problémy související se snadnou dostupností a nadměrným využíváním sociálních sítí, které následně ovlivňuje lidskou společnost. Práce se věnuje vlivu sociálních sítí na jazyk, mezilidsko...

  9. O cheiro das palavras: o olfato na narrativa literária

    OpenAIRE

    Gomes, Cristina

    2009-01-01

    Este trabalho, de natureza teórica e criativa, pretende realizar uma investigação para uma teoria do olfato na literatura. Para isso, deve analisar em que situação encontra-se a narrativa contemporânea quando lida com o olfato. Que papel desempenha o sentido do olfato na literatura? Quais são os métodos de escrita sobre o olfato? Como pode o cheiro ser capturado no papel? O trabalho consiste de um capítulo teórico seguido da novela literária A Rua das Laranjeiras. Ce travail, de nature thé...

  10. Aspectos socioambientais e qualidade da água de dessalinizadores nas comunidades rurais de Pentecoste-CE

    Directory of Open Access Journals (Sweden)

    Antônia Leila Rocha Neves

    2017-01-01

    Full Text Available Os dessalinizadores de água salobra de poços são bastante utilizados para dotar as comunidades rurais do semiárido brasileiro com água potável, sendo considerada uma tecnologia social de convivência com a seca. No entanto, na dessalinização, além da água potável, é gerada uma água residuária (rejeito altamente salina que pode gerar sérios impactos ambientais negativos. Objetivou-se avaliar a qualidade da água e a percepção dos usuários quanto aos aspectos socioambientais relacionados à utilização de equipamentos de dessalinização instalados em oito localidades em Pentecoste, Ceará (Mulungu, Muquenzinho, Irapuá, Macacos, Barra do Leme, Capivara, Lagoa da Porta e Providência. Em cada localidade, foram coletadas três amostras de água do poço, dessalinizada e de rejeito, para caracterização físico-química. Os valores de CE para o rejeito variaram de 4,2 a 7,6 dS m-1, representando riscos para o ambiente de acordo com padrões estabelecidos mundialmente. A localidade de Muquenzinho apresenta os maiores valores de pH, CE, Na e Ca para água do poço, dessalinizada e rejeito, em relação às demais localidades. A maior parte do rejeito gerado é utilizada para alimentação animal e a grande maioria da população, independente da localidade, não tem conhecimento se o uso desse rejeito causa algum dano à saúde humana ou ao ambiente.

  11. Projected shell model study of neutron-deficient 122Ce

    Indian Academy of Sciences (India)

    Rani Devi; B D Sehgal; S K Khosa

    2006-09-01

    The observed excited states of 122Ce nucleus have been studied in the frame-work of projected shell model (PSM). The yrast band has been studied up to spin 26 ħ. The first band crossing has been predicted above a rotational frequency of 0.4 MeV/ħ that corresponds to first backbending. The calculation reproduces the experimentally observed ground state band up to spin 14ħ. The electromagnetic quantities, transition quadrupole moments and -factors are predicted and there is a need to measure these quantities experimentally.

  12. Microscopic IBM-1 description of collective states in 128Ce

    Directory of Open Access Journals (Sweden)

    Mikhajlov V. M.

    2012-12-01

    Full Text Available Microscopical quasiparticle theory is developed to calculate the IBM-1 parameters entering the Hamiltonian and E2–operator. The theory takes into account the impact of noncollective phonons and predicts alterations of the superconducting properties along the excitation spectrum, whereas the most collective phonon (the image of the IBM d-boson is practically invariable. Calculations of the energy spectrum and probabilities of E2–transitions (without effective nucleon charges were performed for 128Ce. The results obtained are in satisfactory agreement with experimental data.

  13. Kinetic Study of Ce4+ Extraction with Cyanex 923

    Institute of Scientific and Technical Information of China (English)

    于桂红; 乐善堂; 李德谦; 凤优游

    2001-01-01

    Ce4+ extraction rate from aqueous sulphate solutions by Cyanex923 in heptane was studied using a constant interfacial cell with laminar flow at 30 ℃. The experimental hydrodynamic conditions were chosen and the contribution of diffusion to the measured rate of reaction was minimized. Cerium extraction rate was measured at different chemical composition by varying the concentrations of hydrogen ion, sulphate and Cyanex923. A cerium-Cyanex923(B) extractive is formed at the interface. The data were analyszed in terms of pseudo-first order constants and a reaction mechanism was developed.

  14. Programming Windows® Embedded CE 60 Developer Reference

    CERN Document Server

    Boling, Douglas

    2010-01-01

    Get the popular, practical reference to developing small footprint applications-now updated for the Windows Embedded CE 6.0 kernel. Written by an authority on embedded application development, this book focuses in on core operating concepts and the Win32 API. It delivers extensive code samples and sample projects-helping you build proficiency creating innovative Windows applications for a new generation of devices. Discover how to: Create complex applications designed for the unique requirements of embedded devicesManage virtual memory, heaps, and the stack to minimize your memory footprintC

  15. Preparation and Characterization of Nanocrystalline CeO2 by Precipitation Method

    Institute of Scientific and Technical Information of China (English)

    董相廷; 李明; 张伟; 刘桂霞; 洪广言

    2002-01-01

    CeO2 nanocrystalline particulates with different sizes were prepared by precipitation method using ethanol as dispersive and protective reagent. XRD spectra show that the synthesized CeO2 has cubic crystalline structure of space group O5H-FM3M, when calcination temperature is in the range of 250~800 ℃. TEM images reveal that CeO2 particles are spherical in shape. The average size of the particles increases with the increase of calcination temperature. Thermogravimetric analysis indicates that the weight loss of precursor mainly depends on the calcination temperature, and little depends on the calcination time. Measurements of CeO2 relative density show that the relative density of CeO2 nanocrystalline powders increases with increasing CeO2 particle size.

  16. Long Lasting Phosphorescence in Eu2+ and Ce3+ Co-Doped Strontium Borate Glasses

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Long lasting phosphorescence (LLP) was observed in Eu2+, Ce3+ co-doped strontium borate glasses prepared under the reducing atmosphere due to the emission of both Eu2+ and Ce3+. The methods of photoluminescence, thermoluminescence and phosphorescence were used to study the samples, and possible mechanism was suggested. The co-doping of Ce3+ ions poisoned the phosphorescence emission of Eu2+ because of the competition to obtain the trapped electron. The phosphorescence of Ce3+ in the sample decays more quickly than that of Eu2+, which is suggested for the reason that the emission energy of Ce3+ is higher or the distance between Ce3+ and electron traps of the glasses is longer.

  17. Electrochemical behavior of Ce(Ⅲ) in LiF-BaF2 melts

    Institute of Scientific and Technical Information of China (English)

    LIN Rushan; YE Guoan; HE Hui; TANG Hongbin; OUYANG Yinggen

    2012-01-01

    The electrochemical behavior of Ce(Ⅲ) was investigated in the molten LiF-BaF2 (81 mo1.%-19 mol.%) on a molybdenum elec-trode in the temperature range of 1098-1188 K using cyclic voltammetry and chronopotentiometry.It was observed that CeF3 could be reduced into cerium metal in a reversible one-step process exchanging three electrons (Ce(Ⅲ)+3e-→,Ce(0)) at the operating temperatures on amolybdenum cathode.The electrochemical reduction process was controlled by the diffusion of Ce(Ⅲ) in the solution.The Ce(Ⅲ) diffusion coefficients were calculated at different temperatures and the values obeyed the Arrhenius law with an activation energy of 87.5 kJ/mol.

  18. Magnetic Compton scattering study of CeRh3B2

    Science.gov (United States)

    Sakurai, Y.; Itou, M.; Tamura, J.; Nanao, S.; Thamizhavel, A.; Inada, Y.; Galatanu, A.; Yamamoto, E.; Onuki, Y.

    2003-07-01

    The spin-polarized electron momentum distribution (magnetic Compton profile: MCP) of ferromagnetic CeRh3B2 has been measured using the magnetic Compton scattering technique at 10 K for the [11bar 20] direction. In this compound, the orbital moment dominates the magnetization. An analysis of the MCP reveals that the Ce 4f and Ce 5d spin moments are aligned parallel with a value of -0.68 +/- 0.08 and 0.41 +/- 0.04muB, respectively, while Rh 4d electrons do not carry any significant spin moment. The ratio of orbital to spin moments for Ce 4f electrons, which has been determined from comparison of the present data with recent polarized neutron diffraction data, is rather smaller than that for Ce3+ ions. This result implies strong hybridization of the Ce 4f orbital with the orbitals on the surrounding ions.

  19. ETAŽNA LASTNINA S POUDARKOM NA ZVEtL

    OpenAIRE

    Cvetko, Tadej

    2014-01-01

    Etažna lastnina je lastnina posameznega dela zgradbe in solastnina na skupnih delih, ki služijo vsem ali nekaterim posameznim delom zgradbe. Etažna lastnino na območju Republike Slovenije je uvedel Zakon o lastnini na delih stavbe kot odgovor na potrebo po hitri nacionalizaciji stanovanj in odrazu doslednega uvajanja osnovne ideje takratnega socialističnega duha t.j. družbene lastnine. Slovenija kot mlada demokratična država je ob tranziciji iz socialističnega v demokratični sistem poskušala ...

  20. Most na rampě křižovatky v Brně

    OpenAIRE

    Novotný, Jan

    2013-01-01

    Práce se zabývá řešením půdorysně zakřiveného mostu na rampě v Brně. Navrženou nosnou konstrukcí je spojitý nosník tvořený dvoukomorou. Na tuto konstrukci jsou uvažovány účinky dopravy dle normy ČSN EN 1991-2. Na základě výsledných namáhání je konstrukce dimenzována. Thesis deals with horizontally curved bridge on the ramp in Brno. Designed structure is continous beam formed by bicameral shape, on which are considered the effects of traffic according to ČSN EN 1991-2. Based on the results ...

  1. Suppression mechanism of radiation-induced darkening by Ce doping in Al/Yb/Ce-doped silica glasses: Evidence from optical spectroscopy, EPR and XPS analyses

    Science.gov (United States)

    Shao, Chongyun; Xu, Wenbin; Ollier, Nadege; Guzik, Malgorzata; Boulon, Georges; Yu, Lu; Zhang, Lei; Yu, Chunlei; Wang, Shikai; Hu, Lili

    2016-10-01

    Yb3+/Al3+ co-doped silica glasses with different Ce2O3 contents were prepared using the sol-gel method combined with high-temperature sintering. Changes in refractive index, absorption, emission and fluorescence lifetime of these glasses caused by X-ray irradiation were recorded and analyzed systematically. It is found that co-doping with certain amount of Ce could greatly improve the radiation resistance without evident negative effects on the basic optical properties of the Yb3+ ions in the near-infrared region. The nature of the radiation-induced color centres and the mechanism by which Ce prevented the formation of these centres were studied using optical absorption, electron paramagnetic resonance (EPR), and X-ray photoelectron spectroscopy (XPS) methods. Direct evidence confirmed that trapped electron centres (Yb2+/Si-E'/Al-E') and trapped hole centres (Al-OHCs) were effectively inhibited by Ce doping, which was correlated to the coexistence of the redox couple Ce3+/Ce4+ in the glasses. These results are helpful to understand the micro-structural origin and the suppression mechanism by Ce co-doping of the photodarkening effect in Yb3+-doped silica fibers.

  2. Synthesis and Characterization of Ce-Doped Y3Al5O12 (YAG:Ce Nanopowders Used for Solid-State Lighting

    Directory of Open Access Journals (Sweden)

    Do Ngoc Chung

    2014-01-01

    Full Text Available Nano-Ce-doped Y3Al5O12 (YAG:Ce powders were synthesized by using a sol-gel low temperature combustion method, followed by thermal annealing. The annealing temperature for enriching nanoparticles was optimized and found to be 1000°C. The process for enriching uniform nanoparticles of YAG:Ce powder was carried out by using the nanosteam technique (NST. The nanoparticles obtained from this NST treatment had a size in the range of 9–20 nm. Measurements of the photoluminescence spectra of the dispersed YAG:Ce nanoparticles solutions showed a blue shift in the photoemission with a value of ca. 10 nm in the green region. WLEDs made from the blue LED chip coated with the nano-YAG:Ce + MEH-PPV composite epoxy exhibit white light with a broad band luminescent spectrum and a high color rending index (CRI. The photoluminescence spectra of the YAG:Ce nanoparticles showed a potential application of the prepared nanostructured YAG:Ce phosphor not only in energy-efficient solid-state lighting, but also in optoelectronic devices, including organic composite solar cells. In addition, it is suggested that NST can be applied for the enrichment of uniform inorganic nanoparticles.

  3. Visible light induced degradation of methylene blue using CeO2/V2O5 and CeO2/CuO catalysts.

    Science.gov (United States)

    Saravanan, R; Joicy, S; Gupta, V K; Narayanan, V; Stephen, A

    2013-12-01

    In the present study, the nanocatalysts CeO2, V2O5, CuO, CeO2/V2O5 and CeO2/CuO were synthesized by thermal decomposition method. This method is simple, fast and cost effective compared with other preparation methods. The synthesized catalysts were characterized by different techniques. The XRD and XPS results confirmed the structure and the oxidization states of the nanocomposite materials. DRS results suggested that the prepared CeO2/V2O5 and CeO2/CuO nanocomposites can generate more electrons and holes under visible light irradiation. The photocatalytic activities of prepared catalysts were evaluated using the degradation of aqueous methylene blue solution as a model compound under visible light irradiation. In addition, the nanocomposite (CeO2/V2O5 and CeO2/CuO) materials were employed to degrade the textile effluent under visible light condition.

  4. Comparison of Efficiencies and Mechanisms of Catalytic Ozonation of Recalcitrant Petroleum Refinery Wastewater by Ce, Mg, and Ce-Mg Oxides Loaded Al2O3

    Directory of Open Access Journals (Sweden)

    Chunmao Chen

    2017-02-01

    Full Text Available The use of catalytic ozonation processes (COPs for the advanced treatment of recalcitrant petroleum refinery wastewater (RPRW is rapidly expanding. In this study, magnesium (Mg, cerium (Ce, and Mg-Ce oxide-loaded alumina (Al2O3 were developed as cost efficient catalysts for ozonation treatment of RPRW, having performance metrics that meet new discharge standards. Interactions between the metal oxides and the Al2O3 support influence the catalytic properties, as well as the efficiency and mechanism. Mg-Ce/Al2O3 (Mg-Ce/Al2O3-COP reduced the chemical oxygen demand by 4.7%, 4.1%, 6.0%, and 17.5% relative to Mg/Al2O3-COP, Ce/Al2O3-COP, Al2O3-COP, and single ozonation, respectively. The loaded composite metal oxides significantly increased the hydroxyl radical-mediated oxidation. Surface hydroxyl groups (–OHs are the dominant catalytic active sites on Al2O3. These active surface –OHs along with the deposited metal oxides (Mg2+ and/or Ce4+ increased the catalytic activity. The Mg-Ce/Al2O3 catalyst can be economically produced, has high efficiency, and is stable under acidic and alkaline conditions.

  5. Influence of synthesis conditions on the crystal structure of the powder formed in the ZrO2 - Ce2O3/CeO2 system.

    Science.gov (United States)

    Popov, V. V.; Menushenkov, A. P.; Khubbutdinov, R. M.; Svetogorov, R. D.; Zubavichus, Ya V.; Sharapov, A. S.; Kurilkin, V. V.

    2016-09-01

    Influence of synthesis conditions (type of atmosphere, reduction and oxidation, annealing temperature) on the chemical composition and structure of the compounds formed in the “ZrO2 - Ce2O3 / CeO2” system has been investigated by X-ray absorption fine structure (XAFS) spectroscopy combined with X-ray diffraction (XRD) and thermogravimetric analysis (TGA). It is revealed that isothermal annealing of precursor at temperatures less than 1000 °C in air leads to formation of Ce0.5Zr0.5O2 powders with cubic fluorite-type structure (Fm-3m). Further increase of annealing temperatures above 1000 °C causes decomposition of formed crystal structure into two phases: cubic and tetragonal. Annealing in reduction hydrogen atmosphere causes formation of Ce4 + 2xCe3 + 2-2xZr2O7 + x compounds with intermediate valency of cerium, where value of x depends on the reducing conditions and treatment parameters of precursor. Annealing in vacuum at 1400 °C strongly reduces the content of Ce4+ in a powder samples and leads to formation of pyrochlore structure (space group Fd-3m) with practically Ce3+ valence state.

  6. 3CE Methodology for Conducting a Modeling, Simulation, and Instrumentation Tool Capability Analysis

    Science.gov (United States)

    2010-05-01

    System Design System Dev DT&E IOT &E Operations 3CE – Core Products Process & Procedures Data Toolbox 3CE Network TRADOC RDECOMATEC 3CE...JCS COCOM FCB Strategic Guidance Materiel Solution Analysis ICD MDD Technology Opportunities & Resources AOA LiveVirtual Constructive Concept Dev ... DEV , DTE, SIMEX, LUT, L-V-C, etc… • Research Requirements •Test Requirements •Training Requirements • PM Requirements Source of Requirements

  7. Structural and magnetic phase transitions in CeCu6 -xTx (T =Ag ,Pd )

    Science.gov (United States)

    Poudel, L.; de la Cruz, C.; Payzant, E. A.; May, A. F.; Koehler, M.; Garlea, V. O.; Taylor, A. E.; Parker, D. S.; Cao, H. B.; McGuire, M. A.; Tian, W.; Matsuda, M.; Jeen, H.; Lee, H. N.; Hong, T.; Calder, S.; Zhou, H. D.; Lumsden, M. D.; Keppens, V.; Mandrus, D.; Christianson, A. D.

    2015-12-01

    The structural and the magnetic properties of CeCu6 -xAgx (0 ≤x ≤0.85 ) and CeCu6 -xPdx (0 ≤x ≤0.4 ) have been studied using neutron diffraction, resonant ultrasound spectroscopy (RUS), x-ray diffraction measurements, and first principles calculations. The structural and magnetic phase diagrams of CeCu6 -xAgx and CeCu6 -xPdx as a function of Ag/Pd composition are reported. The end member, CeCu6, undergoes a structural phase transition from an orthorhombic (P n m a ) to a monoclinic (P 21/c ) phase at 240 K. In CeCu6 -xAgx , the structural phase transition temperature (Ts) decreases linearly with Ag concentration and extrapolates to zero at xS ≈0.1 . The structural transition in CeCu6 -xPdx remains unperturbed with Pd substitution within the range of our study. The lattice constant b slightly decreases with Ag/Pd doping, whereas a and c increase with an overall increase in the unit cell volume. Both systems, CeCu6 -xAgx and CeCu6 -xPdx , exhibit a magnetic quantum critical point (QCP), at x ≈0.2 and x ≈0.05 , respectively. Near the QCP, long range antiferromagnetic ordering takes place at an incommensurate wave vector (δ10 δ2), where δ1˜0.62 ,δ2˜0.25 ,x =0.125 for CeCu6 -xPdx and δ1˜0.64 ,δ2˜0.3 ,x =0.3 for CeCu6 -xAgx . The magnetic structure consists of an amplitude modulation of the Ce moments which are aligned along the c axis of the orthorhombic unit cell.

  8. Capillary electrophoresis coupled to mass spectrometry (CE-MS): twenty years of development

    OpenAIRE

    Nilson Antonio Assunção; Etelvino José Henriques Bechara; Ana Valéria Colnaghi Simionato; Marina Franco Maggi Tavares; Emanuel Carrilho

    2008-01-01

    CE-MS has been increasingly used for analysis of a vast array of compounds. This article reviews the different electrophoretic modes, interfaces and mass analyzers that are commonly used in the CE-MS coupling, as well as the technique advantages and performance characteristics. A large compilation of CE-MS applications is also presented. Therefore, this review is both a guide for beginners and a collection of key references for people who are familiar to the technique. Furthermore, this is th...

  9. Eletroforese capilar acoplada à espectrometria de massas (CE-MS): vinte anos de desenvolvimento

    OpenAIRE

    Assunção, Nilson Antonio [UNIFESP; Bechara, Etelvino José Henriques [UNIFESP; Simionato,Ana Valéria Colnaghi; Tavares, Marina Franco Maggi; Carrilho, Emanuel

    2008-01-01

    CE-MS has been increasingly used for analysis of a vast array of compounds. This article reviews the different electrophoretic modes, interfaces and mass analyzers that are commonly used in the CE-MS coupling, as well as the technique advantages and performance characteristics. A large compilation of CE-MS applications is also presented. Therefore, this review is both a guide for beginners and a collection of key references for people who are familiar to the technique. Furthermore, this is th...

  10. Study of magnetic behaviour of CeRh3B2 using111Cd probe

    Science.gov (United States)

    Nyayate, M. N.; Devare, S. H.; Devare, H. G.

    1989-06-01

    Using111Cd probe nuclei, the transferred H hf( T) is measured down to 35 K in CeRh3B2 using TDPAC technique. The angle β between the EFG and the direction of magnetization is obtained to be 90°. The observed small H hf( T) may be a consequence of the reduced moment on Ce in CeRh3B2.

  11. Anomalous magnetism of CeRh3B2 under pressure

    Science.gov (United States)

    Shaheen, S. A.; Schilling, J. S.; Klavins, P.; Vining, C. B.; Shelton, R. N.

    Whereas CeRh3B2 possesses the highest magnetic ordering temperature (T sub c approx. = 115K) of any Ce-compound with nonmagnetic constituents, LaRh3B2 becomes superconducting below 2.5K. Recent magnetization measurements under pressure as well as lattice parameter and specific heat studies shed light on the nature of the anomalous magnetic state in CeRh3B2.

  12. Nanocrystalline Ce1- x La x O2- δ Solid Solutions Synthesized by Hydrolyzing and Oxidizing

    Science.gov (United States)

    Hou, Xueling; Xue, Yun; Han, Ning; Lu, Qianqian; Wang, Xiaochen; Phan, Manh-Huong; Zhong, Yunbo

    2016-05-01

    We undertook a novel batch production approach for the synthesis of CeO2 nanopowders doped with rare earth elements. Solid solution nanopowders of Ce1- x La x O2- δ ( x = 0.15) were successfully synthesized in a large-scale and low-cost production by hydrolyzing and oxidizing Ce-La-C alloys at room temperature and subsequent calcining of their powders at different temperatures (873-1073 K) for 1 h. The Ce-La-C alloys were prepared in a vacuum induction melting furnace. The final products were characterized by x-ray diffraction, transmission electron microscopy, Brunner-Emmet-Teller (BET) surface area analyzer, and Raman spectroscopy. The calculated lattice parameters of the cubic fluorite-type phase of CeO2 tended to increase when La3+ was incorporated into CeO2. The F 2g band shift and the absence of a peak corresponding to La2O3 in the Raman spectra consistently confirmed the incorporation of the La3+ ion into CeO2, and the formation of Ce1- x La x O2- δ solid solutions as manifested by increased oxygen vacancy defects. High-quality Ce1- x La x O2- δ nanopowders of ~10-15 nm diameter with a high BET surface area of ~77 m2 g-1 were obtained. The average crystallite size of Ce1- x La x O2- δ was found to be smaller than that of CeO2 for the same calcination temperature of 1073 K, demonstrating that the introduction of La3+ into CeO2 can stabilize the host lattice and refine the grain size at high temperatures.

  13. Adsorption behaviors of thiophene, benzene, and cyclohexene on FAU zeolites: Comparison of CeY obtained by liquid-, and solid-state ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Yucai [College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266555, Shandong (China); Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Province, Liaoning Shihua University, Fushun 113001, Liaoning (China); Mo, Zhousheng; Yu, Wenguang; Dong, Shiwei; Duan, Linhai [College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266555, Shandong (China); Gao, Xionghou, E-mail: gaoxionghou@petrochina.com.cn [Petrochemical Research Institute, PetroChina Company Limited, 9 Dongzhimen North Street, Dongcheng District, Beijing 100007 (China); Song, Lijuan, E-mail: lsong56@263.net [College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266555, Shandong (China); Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Province, Liaoning Shihua University, Fushun 113001, Liaoning (China)

    2014-02-15

    Cerium containing Y zeolites were prepared by liquid- (L-CeY) and solid- (S-CeY) state ion exchange from NaY and HY, respectively. The structural and textural properties were characterized by XRD and N{sub 2} adsorption, and acidity properties were characterized by NH{sub 3} temperature-programmed desorption (NH{sub 3}-TPD) and in situ FTIR spectrum of chemisorbed pyridine (in situ Py-FTIR). Furthermore, the single component adsorption and multi-component competitive adsorption behavior of thiophene, benzene and cyclohexene on those zeolites have also been studied by using vapor adsorption isotherms, solution adsorption breakthrough curves, thermogravimetry and derivative thermogravimetry (TG/DTG), frequency response (FR) and in situ FTIR techniques. The results indicate that the primary adsorption mode of benzene is simply micropore filling process, but the nature of effect of aromatics on selective adsorption of thiophene is competitive adsorption. The strong chemical adsorptions and protonization reactions of thiophene and cyclohexene occur upon the Brönsted acid sites of the HY and L-CeY zeolites, and the preferable acid catalytic protonization reactions of olefins hinder the further adsorption of sulfur compounds.

  14. Hot Corrosion Studies of Detonation-Gun-Sprayed NiCrAlY + 0.4 wt.% CeO2 Coated Superalloys in Molten Salt Environment

    Science.gov (United States)

    Kamal, Subhash; Jayaganthan, R.; Prakash, Satya

    2011-08-01

    Rare earth oxide (CeO2) has been incorporated in NiCrAlY alloy and hot corrosion resistance of detonation-gun-sprayed NiCrAlY + 0.4 wt.% CeO2 coatings on superalloys, namely, superni 75, superni 718, and superfer 800H in molten 40% Na2SO4-60% V2O5 salt environment were investigated at 900 °C for 100 cycles. The coatings exhibited characteristic splat globular dendritic structure with diameter similar to the original powder particles. The weight change technique was used to establish corrosion kinetics. X-ray diffraction (XRD), field emission scanning electron microscopy/energy-dispersive analysis (FE-SEM/EDAX), and x-ray mapping techniques were used to analyze the corrosion products. Coated superfer 800H alloy showed the highest corrosion resistance among the examined superalloys. CeO2 was found to be distributed in the coating along the splat boundaries, whereas Al streaks distributed non-uniformly. The main phases observed for the coated superalloys are oxides of Ni, Cr, Al, and spinels, which are suggested to be responsible for developing corrosion resistance.

  15. Fabrication of a novel Mg-RE (Nd,Ce) intermetallic compound coating by molten salt diffusion and its effect on corrosion resistance of magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    韩宝军; 古东懂; 何琼; 张小联; 彭光怀; 杨初斌

    2016-01-01

    A novel Mg-rare earth (Nd,Ce) coating containing intermetallic compound was fabricated on the surface of the AZ91D magnesium alloy by bathing the sample in a NaCl-KCl-LiCl-NdCl3-CeCl3 molten salt. The cross-sectional morphology, microstruc-ture and phase composition of the coating were investigated by scanning electron microscopy (SEM), transmission electron micros-copy (TEM) and energy dispersive spectroscopy (EDS). The corrosion resistance was characterized by the potentiodynamic polariza-tion curves. The SEM observation indicated that a continuous and compact diffusion coating was obtained on the surface of SMATed AZ91D magnesium alloy and the XRD and TEM investigations revealed that the new phases were Al2Ce and Al2Nd intermetallic. The potentiodynamic polarization curves showed that the Mg-RE coating improved the corrosion resistance of the AZ91D magne-sium alloy, and the corrosion current density of the coated sample was about 1510 mA/cm2 lower than the uncoated sample.

  16. Adsorption behaviors of thiophene, benzene, and cyclohexene on FAU zeolites: Comparison of CeY obtained by liquid-, and solid-state ion exchange

    Science.gov (United States)

    Qin, Yucai; Mo, Zhousheng; Yu, Wenguang; Dong, Shiwei; Duan, Linhai; Gao, Xionghou; Song, Lijuan

    2014-02-01

    Cerium containing Y zeolites were prepared by liquid- (L-CeY) and solid- (S-CeY) state ion exchange from NaY and HY, respectively. The structural and textural properties were characterized by XRD and N2 adsorption, and acidity properties were characterized by NH3 temperature-programmed desorption (NH3-TPD) and in situ FTIR spectrum of chemisorbed pyridine (in situ Py-FTIR). Furthermore, the single component adsorption and multi-component competitive adsorption behavior of thiophene, benzene and cyclohexene on those zeolites have also been studied by using vapor adsorption isotherms, solution adsorption breakthrough curves, thermogravimetry and derivative thermogravimetry (TG/DTG), frequency response (FR) and in situ FTIR techniques. The results indicate that the primary adsorption mode of benzene is simply micropore filling process, but the nature of effect of aromatics on selective adsorption of thiophene is competitive adsorption. The strong chemical adsorptions and protonization reactions of thiophene and cyclohexene occur upon the Brönsted acid sites of the HY and L-CeY zeolites, and the preferable acid catalytic protonization reactions of olefins hinder the further adsorption of sulfur compounds.

  17. Non-aqueous CE-MS of cinchona alkaloids - characterization of a novel CE-ESI-MS interface

    DEFF Research Database (Denmark)

    Hansen, Frederik André; Hansen, Steen Honoré; Petersen, Nickolaj J.

    the composition of alkaloids in Cinchona bark. One common problem for sheatless interfaces for CE-MS has been establishing a stable electric contact at the end of the separation capillary that does not induce band broadening or affect the spray stability. In our device the electric contact is generated through....... Furthermore, the increased conductivity of the buffer in the fracture generates field free pumping of the analytes towards the ESI spray tip. In this study the device was used to analyze the four major alkaloids (diastereomeric pairs of quinine/quinidine and cinchonine/cinchonidine) in Cinchona bark samples...

  18. CE-4 Mission and Future Journey to Lunar

    Science.gov (United States)

    Zou, Yongliao; Wang, Qin; Liu, Xiaoqun

    2016-07-01

    Chang'E-4 mission, being undertaken by phase two of China Lunar Exploration Program, represents China's first attempt to explore farside of lunar surface. Its probe includes a lander, a rover and a telecommunication relay which is scheduled to launch in around 2018. The scientific objectives of CE-4 mission will be implemented to investigate the lunar regional geological characteristics of landing and roving area, and also will make the first radio-astronomy measurements from the most radio-quiet region of near-earth space. The rover will opreate for at least 3 months, the lander for half a year, and the relay for no less than 3 years. Its scinetific instruments includes Cameras, infrared imaging spectrometer, Penetrating Radar onboard the rover in which is the same as the paylads on board the CE-3 rover, and a Dust-analyzer, a Temperature-instrument and a Wide Band Low Frequency Digital Radio Astronomical Station will be installed on board the lander. Our scientific goals of the future lunar exploration will aim at the lunar geology, resources and surface environments. A series of exploraion missions such as robotic exploration and non-manned lunar scientific station is proposed in this paper.

  19. The naringenin-induced exoproteome of Rhizobium etli CE3.

    Science.gov (United States)

    Meneses, Niurka; Taboada, Hermenegildo; Dunn, Michael F; Vargas, María Del Carmen; Buchs, Natasha; Heller, Manfred; Encarnación, Sergio

    2017-03-02

    Flavonoids excreted by legume roots induce the expression of symbiotically essential nodulation (nod) genes in rhizobia, as well as that of specific protein export systems. In the bean microsymbiont Rhizobium etli CE3, nod genes are induced by the flavonoid naringenin. In this study, we identified 693 proteins in the exoproteome of strain CE3 grown in minimal medium with or without naringenin, with 101 and 100 exoproteins being exclusive to these conditions, respectively. Four hundred ninety-two (71%) of the extracellular proteins were found in both cultures. Of the total exoproteins identified, nearly 35% were also present in the intracellular proteome of R. etli bacteroids, 27% had N-terminal signal sequences and a significant number had previously demonstrated or possible novel roles in symbiosis, including bacterial cell surface modification, adhesins, proteins classified as MAMPs (microbe-associated molecular patterns), such as flagellin and EF-Tu, and several normally cytoplasmic proteins as Ndk and glycolytic enzymes, which are known to have extracellular "moonlighting" roles in bacteria that interact with eukaryotic cells. It is noteworthy that the transmembrane ß (1,2) glucan biosynthesis protein NdvB, an essential symbiotic protein in rhizobia, was found in the R. etli naringenin-induced exoproteome. In addition, potential binding sites for two nod-gene transcriptional regulators (NodD) occurred somewhat more frequently in the promoters of genes encoding naringenin-induced exoproteins in comparison to those ofexoproteins found in the control condition.

  20. Implantation sites of Ce and Gd in diamond

    CERN Document Server

    Bharuth-Ram, K; Hofsäss, H C; Ronning, C; Dietrich, M

    2002-01-01

    The implantation sites of rare earth (RE) probes /sup 141/Ce (t/sub 1 /2/=32 d) and /sup 149/Gd (t/sub 1/2/=9.28 d) in diamond have been investigated using the emission channeling (EC) technique. Parent isotopes /sup 141/Cs and /sup 149/Dy were implanted into type IIa, diamond samples at an energy of 60 keV at the online isotope separator ISOLDE at CERN. /sup 141/Cs decays through the chain /sup 141/Cs-/sup 141/Ba-/sup 141/La-/sup 141/Ce-/sup 141/ Pr. EC measurements were made on the 102 keV conversion electrons emitted in the decay of /sup 141/Pr to its ground state. The decay of /sup 149 /Dy follows the chain /sup 149/Dy-/sup 149/Tb-/sup 149/Gd-/sup 149 /Eu-/sup 149/Sm. EC measurements were made on the 101 keV electrons emitted in the decay of /sup 149/Eu. Two-dimensional channeling patterns of the conversion electrons were obtained along and axial directions by raster scans with a Si surface barrier detector. Comparison of the observed patterns with simulated spectra show that in diamond 45-50% of the RE...

  1. Optical properties of Ce3+ doped fluorophosphates scintillation glasses

    Science.gov (United States)

    Yao, Yongxin; Liu, Liwan; Zhang, Yu; Chen, Danping; Fang, Yongzheng; Zhao, Guoying

    2016-01-01

    Fluorophosphates (P2O5-BaO-BaF2-Al2O3-Gd2O3-Ce2O3) glasses with different Gd2O3 and BaF2 concentrations have been prepared by a melt quenching method. The effect of Gd2O3 and BaF2 on the glass performance including the density, absorption as well as luminescence properties under both ultraviolet (UV) and X-ray excitation was studied systematically. Energy transfer from Gd3+ to Ce3+ plays an important role in the scintillation mechanism of these glasses and the optimum concentration of Gd2O3 is found to be approximately 3 mol%. The highest integrated light emission intensity of these glass samples excited by X-ray is 25% of BGO and the decay time constants are in the range of 25-35 ns, much shorter than the 300 ns decay time of BGO. Meanwhile, replacing lighter compound BaO with the BaF2 can increase the density of the glasses and also improve the light yield.

  2. La vérite sur ce qui nous motive

    CERN Document Server

    Pink, Daniel H

    2011-01-01

    Voici enfin la traduction française du best-seller international DRIVE ! Qu'est-ce qui nous motive vraiment ? Dans quels cas sommes-nous les plus performants et les plus enthousiastes ? La plupart d'entre nous sommes persuadés que les récompenses (salaire, primes...) sont notre meilleure motivation. La logique de la carotte et du bâton finalement... Et si nous faisions fausse route ? En s'appuyant sur quatre décennies d'études scientifiques et psychologiques sur la motivation humaine, Pink démontre que les entreprises dirigent très mal leurs équipes avec d'énormes conséquences sur notre vie (absence d'ambition, lassitude, morosité). Le secret de la performance (et de la satisfaction) dans les entreprises, l'enseignement ou dans notre vie personnelle , c'est le besoin profondément humain de diriger sa propre vie, d'apprendre, de créer de nouvelles choses et de s'améliorer. Dans ce livre, Pink examine les 3 éléments de la motivation, l'autonomie, la maîtrise et le besoin de donner un sens ...

  3. Agp2p, the Plasma Membrane Transregulator of Polyamine Uptake, Regulates the Antifungal Activities of the Plant Defensin NaD1 and Other Cationic Peptides

    OpenAIRE

    Bleackley, Mark R.; Wiltshire, Jennifer L.; Perrine-Walker, Francine; Vasa, Shaily; Burns, Rhiannon L.; van der Weerden, Nicole L.; Anderson, Marilyn A.

    2014-01-01

    Cationic antifungal peptides (AFPs) act through a variety of mechanisms but share the common feature of interacting with the fungal cell surface. NaD1, a defensin from Nicotiana alata, has potent antifungal activity against a variety of fungi of both hyphal and yeast morphologies. The mechanism of action of NaD1 occurs via three steps: binding to the fungal cell surface, permeabilization of the plasma membrane, and internalization and interaction with intracellular targets to induce fungal ce...

  4. Optical spectroscopy of Ce{sup 3+} in BaLiF{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Yamaga, M.; Imai, T. [Department of Electrical and Electronic Engineering, Faculty of Engineering, Gifu University, Gifu 501-1193 (Japan); Shimamura, K.; Fukuda, T. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Honda, M. [Faculty of Science, Naruto University of Education, Naruto 772-8502 (Japan)

    2000-04-10

    The optical absorption spectrum of Ce{sup 3+} in BaLiF{sub 3} crystals consists of several overlapping broad bands. The Ce{sup 3+} luminescence shows broad bands due to moderate electron-phonon interaction in the 5d excited state. Three distinct Ce{sup 3+} sites in the crystal were assigned from the optical spectra. The luminescence spectrum from the dominant Ce{sup 3+} site has a large Stokes shift ({approx}8300 cm{sup -1}), whereas that from one of the two minor Ce{sup 3+} sites has a Stokes shift of half that magnitude ({approx}4400 cm{sup -1}), assuming that the excitation spectrum is almost the same as for the dominant site. The peaks of the lowest-energy absorption and luminescence bands for the other minor Ce{sup 3+} site are shifted to lower energy, and the Stokes shift energy ({approx}7800 cm{sup -1}) is close to that for the dominant site. These three Ce{sup 3+} sites are assigned to configurations of Ce{sup 3+} accompanied by different charge compensators. This assignment is consistent with preliminary electron spin-resonance results indicating that there exist two tetragonal and two orthorhombic Ce{sup 3+} centres in the absence of the cubic centre. (author)

  5. Study of structural and electronic transport properties of Ce-doped LaMnO3

    Indian Academy of Sciences (India)

    Shahid Husain; R J Choudhary; Ravi Kumar; S I Patil; J P Srivastava

    2002-05-01

    The structural and electronic transport properties of La1-CeMnO3 (=0.0-1.0) have been studied. All the samples exhibit orthorhombic crystal symmetry and the unit cell volume decreases with Ce doping. They also make a metal–insulator transition (MIT) and transition temperature increases with increase in Ce concentration up to 50% doping. The system La0.5Ce0.5MnO3 also exhibits MIT instead of charge-ordered state as observed in the hole doped systems of the same composition.

  6. Selective synthesis and growth mechanism of CeVO4 nanoparticals via hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    LIU Fengzhen; SHAO Xin; YIN Yibin; ZHAO Limin; SUN Qiaozhen; SHAO Zhuwei; LIU Xuehua; MENG Xianhua

    2011-01-01

    Selective-controlled structure and shape of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from electron microscopy (FESEM) and energy dispersive spectroscopy (EDS). The influence of hydrothermal temperature, precursor solution concentration on the crystal and morphology of products were further studied. The results showed that the as-synthesized products exhibited pure single-crystal CeVO4 nanoparticles with tetragonal structure. The hydrothermal temperature and precursor solution concentration had important effects on the formation of CeVO4 nanoparticles. Furthermore, the growth mechanism of CeVO4 nanoparticles was explained with Ostwald ripening mechanism.

  7. Metallic oxides supported in CeO{sub 2} and CeO{sub 2}-La{sub 2} O{sub 3} for low temperature shift reaction; Oxidos metalicos suportados em CeO{sub 2} e CeO{sub 2}-La{sub 2} O{sub 3} para reacao shift a baixa temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Maluf, Silvia Salua; Assaf, Elisabete Moreira [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica]. E-mail: sil_maluf@iqsc.usp.br

    2008-07-01

    This work studied copper and zinc oxides supported in CeO{sub 2} and CeO{sub 2}/La{sub 2}O{sub 3}. The catalytic tests for low temperature shift reaction, carried out for samples, showed the Cu-Ce catalyst presents the highest value of CO conversion (50%) and after the Cu-Ce-La catalysts (30%). The other catalysts showed CO conversion in range of 15%. This behavior is related with surface area, and also with the amount of Cu in the surface of samples (author)

  8. Growth and Electronic Properties of Ag Nanoparticles on Reduced CeO2-x(111) Films

    Institute of Scientific and Technical Information of China (English)

    Dan-dan Kong; Yong-he Pan; Guo-dong Wang; Hai-bin Pan; Jun-fa Zhu

    2012-01-01

    Ag nanoparticles grown on reduced CeO2-x thin films have been studied by X-ray photoelectron spectroscopy and resonant photoelectron spectroscopy of the valence band to understand the effect of oxygen vacancies in the CeO2-x thin films on the growth and interfacial electronic properties of Ag.Ag grows as three-dimensional particles on the CeO2-x(111) surface at 300 K.Compared to the fully oxidized ceria substrate surface,Ag favors the growth of smaller particles with a larger particle density on the reduced ceria substrate surface,which can be attributed to the nucleation of Ag on oxygen vacancies.The binding energy of Ag3d increases when the Ag particle size decreases,which is mainly attributed to the final-state screening.The interfacial interaction between Ag and CeO2-x(111) is weak.The resonant enhancement of the 4f level of Ce3+ species in RPES indicates a partial Ce4+→Ce3+ reduction after Ag deposited on reduced ceria surface.The sintering temperature of Ag on CeO 1.85 (111) surface during annealing is a little higher than that of Ag on CeO2 (111) surface,indicating that Ag nanoparticles are more stable on the reduced ceria surface.

  9. Growth and Photoluminescence of Epitaxial CeO2 Film on Si (111) Substrate

    Institute of Scientific and Technical Information of China (English)

    GAO Fei; ZHANG Jian-Hui; QIN Fu-Guang; YAO Zhen-Yu; LIU Zhi-Kai; WANG Zhan-Guo; LIN Lan-Ying

    2001-01-01

    A CeO2 film with a thickness of about 80nm was deposited by a mass-analysed low-energy dual ion beam deposition technique on an Si(111) substrate. Reflection high-energy electron diffraction and x-ray diffraction measurements showed that the film is a single crystal. The tetravalent state of Ce in the film was confirmed by xray photoelectron spectroscopy measurements, indicating that stoichiometric CeO2 was formed. Violet/blue light emission (379.5 nm) was observed at room temperature, which may be tentatively explained by charge transitions from the 4f band to the valence band of CeO2.

  10. Research on CeO2 cap layer for YBCO-coated conductor

    Institute of Scientific and Technical Information of China (English)

    Shi Dong-Qi; Ma Ping; Ko Rock-Kil; Kim Ho-Sup; Chung Jun-Ki; Song Kyu-Jeong; Park Chan

    2007-01-01

    Two groups of coated conductor samples with different thicknesses of CeO2 cap layers deposited by pulsed laser deposition (PLD) under the same conditions have been studied. Of them, one group is of CeO2 films, which are deposited on stainless steel (SS) tapes coated by IBAD-YSZ (IBAD-YSZ/SS), and the other group is of CeO2/YSZ/Y2O3 multilayers, which are deposited on NiW substrates by PLD for the fabrication of YBCO-coated conductor through the RABiTS approach. YBCO film is then deposited on the tops of both types of buffer layers by PLD. The effects of the thickness of the CeO2 film on the texture of the CeO2 film and the critical current density (Jc) of the YBCO film are analysed. For the case of CeO2 film on IBAD-YSZ/SS, there appears a self-epitaxy effect with increasing thickness of the CeO2 film. For CeO2/YSZ/Y2O3/NiW, in which the buffer layers are deposited by PLD, there occurs no self-epitaxy effect, and the optimal thickness of CeO2 is about 50nm. The surface morphologies of the two groups of samples are examined by SEM.

  11. Effect of Cerium on Chemical Short-Range Order of Al-Fe-Ce Amorphous Alloy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The chemical short-range order of Al-Fe-Ce amorphous alloy was studied by means of X-ray diffraction(XRD) and differential scanning calorimetry(DSC). It is found that the prepeak position in X-ray diffraction intensity curve shifts to higher angles as the content of Fe increases, but it shifts to smaller angles as the content of Ce increases. The crystallization character of the amorphous alloy changes with the variation of the content of Fe and Ce. Ce can improve the interaction between atoms and the capacity of compound formation, so it is favorable to Al-based glass formability.

  12. Perturbing the superconducting planes in CeCoIn5 by Snsubstitution

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, M.; Bauer, E.D.; Han, S.-W.; Booth, C.H.; Cornelius,A.L.; Pagliuso, P.G.; Sarrao, J.L.

    2005-01-11

    In contrast to substitution on the Co or Ce site, Sn substitution has a remarkably strong effect on superconductivity in CeCoIn{sub 5-x}Sn{sub x}, with T{sub c} {yields} 0 beyond only {approx}3.6% Sn. Instead of being randomly distributed on in-plane and out-of-plane In sites, extended x-ray absorption fine structure measurements show the Sn atoms preferentially substitute within the Ce-In plane. This result highlights the importance of the In(1) site to impurity scattering and clearly demonstrates the two-dimensional nature of superconductivity in CeCoIn{sub 5}.

  13. Discovering a First-Order Phase Transition in the Li-CeO2 System.

    Science.gov (United States)

    Li, Kaikai; Zhou, Xiaoye; Nie, Anmin; Sun, Sheng; He, Yan-Bing; Ren, Wei; Li, Baohua; Kang, Feiyu; Kim, Jang-Kyo; Zhang, Tong-Yi

    2017-02-08

    An in-depth understanding of (de)lithiation induced phase transition in electrode materials is crucial to grasp their structure-property relationships and provide guidance to the design of more desirable electrodes. By operando synchrotron XRD (SXRD) measurement and Density Functional Theory (DFT) based calculations, we discover a reversible first-order phase transition for the first time during (de)lithiation of CeO2 nanoparticles. The LixCeO2 compound phase is identified to possess the same fluorite crystal structure with FM3M space group as that of the pristine CeO2 nanoparticles. The SXRD determined lattice constant of the LixCeO2 compound phase is 0.551 nm, larger than that of 0.541 nm of the pristine CeO2 phase. The DFT calculations further reveal that the Li induced redistribution of electrons causes the increase in the Ce-O covalent bonding, the shuffling of Ce and O atoms, and the jump expansion of lattice constant, thereby resulting in the first-order phase transition. Discovering the new phase transition throws light upon the reaction between lithium and CeO2, and provides opportunities to the further investigation of properties and potential applications of LixCeO2.

  14. Spectroscopic evidence against Rh 4d itinerant ferromagnetism in CeRh3B2

    Science.gov (United States)

    Sampathkumaran, E. V.; Kaindl, G.; Laubschat, C.; Krone, W.; Wortmann, G.

    1985-03-01

    Valence-band photoemission and IIII-edge x-ray absorption studies were performed on RRh3B2 (R = La, Ce, and Pr) compounds in order to explore the origin of the anomalously high magnetic ordering temperature of CeRh3B2. From the low density of Rh 4d states at EF and the approximate trivalency of Ce, itinerant magnetism in the Rh 4d band can be excluded. Instead, the magnetism is proposed to originate from Ce moments, enhanced by 4f hybridization with Rh d orbitals.

  15. Magnetism in the system Ce1-xLaxRh3B2 (abstract)

    Science.gov (United States)

    Malik, S. K.; Umarji, A. M.; Shenoy, G. K.; Aldred, T. A.; Niarchos, D. G.

    1985-04-01

    The RRh3B2 (R=La to Gd) compounds form in the hexagonal CeCo3B2-type structure. The La containing compound in this series has been reported to be a superconductor while CeRh3B2 orders magnetically with Ce being in a nearly 3+ state. The magnetic ordering in CeRh3B2 is presumed to arise from the hybridization of nearly localized 4f electrons of Ce with sp conduction electrons or the 4d band of Rh or from the hybridization of the two. We have examined the magnetic behavior of the system Ce1-xLaxRh3B2 (x=0.0, 0.2, 0.4, 0.6, and 0.8). All these compounds (except LaRh3B2) also order magnetically. The Curie temperature decreases from about 115 K for pure Ce compound to 2.3 K for Ce0.2La0.8Rh3B2. The magnetic moments per formula unit remains nearly constant for 0Ce1-xLaxRh3B2 for x ranging from 0.0 to 0.8. The La-rich side is being investigated for the occurrence of superconductivity. Details will be published elsewhere.

  16. Microstructure and properties of a Mo-CeO2 heated cathode material

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jiuxing; WAN Xiaofeng; LI Xiangbo; ZHOU Wenyuan; ZHOU Meiling

    2004-01-01

    The microstructure, mechanical properties, and electron-emission properties of a newly developed heated cath ode material Mo-CeO2 with 4.0% (mass fraction) of CeO2 were investigated. It is shown that the Mo-CeO2 cathode material possesses high tensile strength and good room-temperature ductility. After carbonized, the Mo-CeO2 cathode material has a higher zero field emission current density and a lower work function compared with the W-ThO2 cathode material.

  17. Effects of CeF3 on properties of self-shielded flux cored wire

    Institute of Scientific and Technical Information of China (English)

    Yu Ping; Tian Zhiling; Pan Chuan; Xue Jin

    2006-01-01

    Effects of CeF3 on properties of self-shielded flux cored wire including welding process, inclusions in weld metal and mechanical properties are systematically studied. Welding smoke and spatter are reduced with the addition of CeF3. The main non-metallic inclusions in weld metal are AlN and Al2 O3. CeF3 can refine non-metallic inclusions and reduce the amount of large size inclusions, which is attributed to the inclusion floating behavior during the solidification of weld metal. The low temperature impact toughness is improved by adding suitable amount of CeF3 in the flux.

  18. Low-temperature catalytic oxidation of NO over Mn-Ce-O_x catalyst

    Institute of Scientific and Technical Information of China (English)

    李华; 唐晓龙; 易红宏; 于丽丽

    2010-01-01

    A series of manganese-cerium oxide catalysts were prepared by different methods and used for low-temperature catalytic oxidation of NO in the presence of excess O2.Their surface properties were evaluated by means of BET and were characterized by using scanning electron microscopy(SEM) and X-ray diffractometer(XRD).The activity test of Mn-Ce-Ox catalysts showed that addition of Ce enhanced the activities of NO oxidation.The most active catalysts with a molar Ce/(Mn+Ce) ratio of 0.3 were prepared by co-precip...

  19. Investigation of the 600 C isothermal section of the Fe-Al-Ce ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Huiyun; Yin, Fucheng [Xiangtan Univ., Hunan (China). School of Materials Science and Engineering; Xiangtan Univ., Hunan (China). Key Laboratory of Materials Design and Preparation Technology of Hunan Province; Li, Zhi [Xiangtan Univ., Hunan (China). School of Materials Science and Engineering; Xiangtan Univ., Hunan (China). Key Laboratory of Materials Design and Preparation Technology of Hunan Province; Xiangtan Univ., Hunan (China). Key Laboratory of Key Film Materials and Application for Equipment (Hunan province); Ji, Li [South China University of Technology, Guangdong (China). School of Materials Science and Engineering

    2017-01-15

    The isothermal section of the Fe-Al-Ce system at 600 C was determined by means of scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray powder diffraction. Twenty three-phase regions were confirmed experimentally, and two three-phase regions could be deduced in this section. Five ternary compounds, i. e., τ{sub 1}, τ{sub 2}, τ{sub 3}, τ{sub 5}, and τ{sub 6}, exist at 600 C. The Fe{sub 2}Ce phase contains 6.6 at.% Al in the Fe-Al-Ce system. The Fe solubility in α-Al, αAl{sub 11}Ce{sub 3}, αAl{sub 3}Ce, Al{sub 2}Ce, AlCe, and AlCe{sub 3} is approximately 1.7 at.%, 1.1 at.%, 1.2 at.%, 1.3 at.%, 5.8 at.%, and 0.1 at.%, respectively, and the solubility of Ce in α-Al, FeAl{sub 3}, Fe{sub 2}Al{sub 5}, FeAl{sub 2}, and FeAl is approximately 0.1 at.%, 1.2 at.%, 1.9 at.%, 0.9 at.%, and 3.7 at.%, respectively.

  20. Crystal structure and magnetic properties of the off-stoichiometric compounds CeNi sub 3 Cu sub 3 and CeNi sub 4 Cu sub 2

    CERN Document Server

    Moze, O; Brück, E; Buschow, K H J

    1998-01-01

    The crystallographic properties of the compounds CeNi sub 3 Cu sub 3 and CeNi sub 4 Cu sub 2 have been investigated by time-of-flight neutron diffraction. A Rietveld profile refinement of the data shows that these compounds crystallize in the hexagonal TbCu sub 7 -type structure and that Ni atoms have a greater preference as compared with Cu atoms for occupying the 2e dumb-bell site. A site preference of Cu atoms for the 2c sites is observed. Magnetic measurements made on these compounds show that the trivalent character of the Ce atoms increases with Cu concentration. (author)

  1. Marketingový mix Restaurace Na chalupě

    OpenAIRE

    Kubíková, Martina

    2013-01-01

    Bakalářská práce se zaměřuje na rozbor marketingu a především marketingového mixu. Tedy na známé definice marketingu, marketingová prostředí a rozbor marketingového mixu, kde jsou zmapovány všechny jeho části (Produkt, Cena, Distribuce, Propagace, Fyzický důkaz, Lidé, Procesy). Z teoretických poznatků, které byly zjištěny v odborné literatuře, je vypracována praktická část. Zde je rozebrán marketingový mix Restaurace Na chalupě a zároveň tak i porovnání dvou provozovatelů, kteří se zde vystří...

  2. Particle-specific toxicity and bioavailability of cerium oxide (CeO2) nanoparticles to Arabidopsis thaliana.

    Science.gov (United States)

    Yang, Xinping; Pan, Haopeng; Wang, Peng; Zhao, Fang-Jie

    2017-01-15

    The use of manufactured cerium oxide nanoparticles (CeO2-NPs) in consumer products has increased markedly over the past decade, and their release into natural ecosystems is unavoidable. This study investigated the phytotoxicity and uptake of CeO2-NPs in Arabidopsis thaliana grown in an agar medium. Although low concentrations of CeO2-NPs had stimulatory effects on plant growth, at higher concentrations, CeO2-NPs reduced growth and had adverse effects on the antioxidant systems and photosystem. Importantly, the toxicity resulted from the nanoparticles per se, rather than from the dissolved Ce ions. CeO2-NPs were taken up and subsequently translocated to shoot tissues, and transmission electron microscopy (TEM) showed the presence of a large number of needle-like particle aggregations in the intercellular regions and the cytoplasm of leaf cells. The up-translocation factor to shoots was independent of the concentrations of Ce in the roots and the supplied forms of Ce (i.e. CeO2-NPs, CeO2-bulk, and ionic Ce), suggesting that endocytosis is likely to be a general mechanism responsible for the translocation of these Ce compounds. These findings provide important information regarding the toxicity and uptake of CeO2-NPs in plants, which needs to be considered in environmental risk assessment for the safe use and disposal of CeO2-NPs.

  3. The effect of Ce dilution on the ferromagnetic ordering and Kondo behavior of CeRuPO

    Science.gov (United States)

    Noorafshan, M.; Nourbakhsh, Z.

    2017-03-01

    The structural, electronic and magnetic properties and Kondo behavior of Ce1-xLax RuPO (x=0, 0.25, 0.5, 0.75 and 1) alloys are investigated using density functional theory by utilizing Wien2k package. The exchange-correlation potential is treated with the generalized gradient approximation (GGA). Moreover, the GGA+U approach (where U is the Hubbard correlation term) is employed to treat the f-electrons properly. We also present a comparative study between the electronic structure and magnetic properties of these alloys within GGA and GGA+U approaches. The calculated lattice parameters and bulk moduli of these alloys as a function of x are in the best agreement with Vegard's linear rule. The total and partial electron density of states and linear coefficient of electronic specific heat of these alloy within GGA and GGA+U are investigated and compared. The effect of La substitution on the Kondo behavior of CeRuPO compound is investigated.

  4. The CO methanation on Rh/CeO 2 and CeO 2/Rh model catalysts: a comparative study

    Science.gov (United States)

    Jenewein, B.; Fuchs, M.; Hayek, K.

    2003-06-01

    Like other reducible oxides, ceria promotes the CO methanation reaction on noble metals, but after high-temperature reduction the promotion is usually reduced and limited to transient conditions. We studied the effect of low- and high-temperature reduction on two types of Rh/ceria model catalysts: "thin film catalysts" consisting of well-defined regular Rh nanoparticles partly embedded in the crystalline ceria support, and "inverse catalysts", i.e. UHV grown ceria submonolayers on polycrystalline Rh surfaces. The turnover rates on either catalyst were related to the free Rh surface area and to the dimensions of the metal-oxide boundary. On thin film catalysts the rates decrease strongly with reduction temperature up to 723 K while no significant structural changes are detectable by ex situ electron microscopy. On ceria-modified surfaces the reaction is initially favoured after reduction below 573 K, but promotion converts to inhibition with increasing reduction temperature. The changing number of Ce III/Ce IV ions on the surface, the oxygen transport to and from the interface, and changes in the free Rh surface area resulting from spreading and reordering of the ceria overlayer are discussed as possible reasons for the observed effects.

  5. Crystal growth and scintillation properties of undoped and Ce3+-doped GdI3 crystals

    Science.gov (United States)

    Ye, Le; Li, Huanying; Wang, Chao; Shi, Jian; Chen, Xiaofeng; Wang, Zhongqing; Huang, Yuefeng; Xu, Jiayue; Ren, Guohao

    2017-02-01

    The growth and scintillation properties of undoped and Ce3+-doped GdI3 crystals were reported in this paper. These GdI3:χ%Ce (χ = 0, 1, 2) crystals were grown by the vertical Bridgman growth technique in evacuated quartz crucibles. X-ray excited optical luminescence spectra of GdI3:Ce exhibit a broad emission band (450 nm-650 nm) peaking at 520 nm corresponding to 5d1→4f1 transition of Ce3+ while the undoped GdI3 crystal consists of a broad band (400 nm-600 nm) and several sharp lines peaking at 462 nm, 482 nm, 492 nm, 549 nm, 579 nm owing to the impurities ions and defects. The excitation spectra of Ce3+ doped GdI3 consist of two broad bands between 300 nm and 500 nm corresponding to 4f1→5d1 absorption of Ce3+. The other absorption peaking at 262 nm in the spectrum of GdI3:2%Ce is assigned to band-to-band exciton transition. The excitation spectrum of undoped GdI3 contains a flat absorption band from 330 to 370 nm and a broad band between 390 and 450 nm peaking at 414 nm corresponding to the absorption of the unintentionally doped Ce3+, Dy3+, Ho3+ impurities and other defects. The emission spectrum of undoped GdI3 under 332 nm excitation has the identical line peaks with the spectrum measured under X-ray excitation. The emission spectra of GdI3:2%Ce and GdI3:1%Ce show a broad band in the range of 450-750 nm with the maximum at 550 nm corresponding to 5d1→4f1 transitions of Ce3+ ion. The GdI3, GdI3:1%Ce and GdI3:2%Ce show fast principle decay time constant 73 ns, 69 ns and 58 ns respectively, besides, the undoped also shows a slow decay constant 325 ns which doesn't appear in Ce3+-doped GdI3 crystal. The energy resolutions of GdI3:χ%Ce (χ = 1, 2) measured at 662 KeV are about 3%-5% and the undoped GdI3 is 13.3%.

  6. Novel nanostructured CeO2 as efficient catalyst for energy and environmental applications

    Indian Academy of Sciences (India)

    Sumanta Kumar Meher; G Ranga Rao

    2014-03-01

    We report here versatile methods to engineer the microstructure and understand the fundamental physicochemical properties of CeO2 to improve its catalytic viability for practical applications. In this context, different morphologies of CeO2 are synthesized using tailored homogeneous precipitation methods and characterized by XRD, BET, SEM and TPR methods. The shuttle-shaped CeO2 prepared under hydrothermal condition shows higher surface area and low-temperature reducibility. The 0.5 wt% Pt-impregnated shuttle-shaped CeO2 shows lower-temperature CO oxidation behaviour as compared to its bulk-like CeO2 (with 0.5 wt% Pt) counterpart, synthesized by conventional-reflux method. Further, nanorod morphology of CeO2 prepared with Cl−as counter ion shows lower-temperature oxidation of soot as compared to the mesoflower morphology of CeO2, prepared with NO$^{−}_{3}$ as counter ion in the reaction medium. Further, linear sweep voltammetry, chronopotentiometry and CO-stripping voltammetry studies are performed to evaluate the promoting activity of CeO2 to Pt/C for ethanol electro-oxidation reaction in acidic media. Results show that CeO2 provides active triple-phase-interfacial sites for suitable adsorption of OH species which effectively oxidize the COads on Pt/C. The results presented here are significant in the context of understanding the physicochemical fine prints of CeO2 and CeO2 based hetero-nanocomposites for their suitability to important catalytic and energy-related applications.

  7. Luminescence of Ce 3+ -Doped MB2Si2O8 (M = Sr, Ba): A Deeper Insight into the Effects of Electronic Structure and Stokes Shift

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Qi [Sun Yat-Sen Univ., Guangzhou, (China); Liu, Chunmeng [Sun Yat-Sen Univ., Guangzhou, (China); Hou, Dejian [Sun Yat-Sen Univ., Guangzhou, (China); Zhou, Weijie [Sun Yat-Sen Univ., Guangzhou, (China); Ma, Chong-Geng [Chongqing Univ. of Posts and Telecommunications (China); Liu, Guokui [Argonne National Lab. (ANL), Argonne, IL (United States); Brik, Mikhail G. [Chongqing Univ. of Posts and Telecommunications (China); Tao, Ye [Chinese Academy of Sciences (CAS), Beijing (China); Liang, Hongbin [Sun Yat-Sen Univ., Guangzhou, (China)

    2015-12-18

    A series of Sr 1 -2x CexNaxB2Si2O8 and Ba 1-2x CexKxB2Si2O8 (x = 0.005, 0.01, 0.02, 0.04, 0.06, 0.08) samples were synthesized by a high-temperature solid-state reaction. The low temperature excitation, emission, and fluorescence decay spectra together demonstrated that all spectral bands arise from the Ce 3+ ions located at only one kind of lattice site. The first-principles calculations of the structural and electronic properties of pure and Ce 3+2Si2O8 (M = Sr, Ba) were performed, and the obtained results were used for understanding the structural changes after doping and identification of the observed position of the host absorption bands. The measured 4f-5d excitation and emission spectra of Ce3+ ions doped in MB2Si2O8 were analyzed and simulated in the framework of the crystal-field (CF) theory. The electron-phonon coupling effect generally ignored in most studies published so far was also taken into account by applying the configurational coordinate model. The validity of such a combined insight into the 5d CF energy level positions and the Stokes shift has been confirmed by analyzing the dependence of the Ce 3+

  8. Tunable luminescence and white light emission of novel multiphase sodium calcium silicate nanophosphors doped with Ce{sup 3+}, Tb{sup 3+}, and Mn{sup 2+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Mickens, Matthew A. [Energy and Environmental Systems, North Carolina A and T State University, Greensboro, NC 27411 (United States); Assefa, Zerihun, E-mail: zassefa@ncat.edu [Department of Chemistry, North Carolina A and T State University, Greensboro, NC 27411 (United States)

    2014-01-15

    This study reports the sol–gel synthesis of sodium calcium multiphase silicate (SCMS) nanophosphors. X-ray powder diffraction indicated the crystallization of devitrite (Na{sub 2}Ca{sub 3}Si{sub 6}O{sub 16}), wollastonite-2M (CaSiO{sub 3}), and cristobalite (SiO{sub 2}) phases that consistently occurred together upon repeated syntheses. The multiphase silicate system was used as a host matrix for varied concentrations of Ce{sup 3+}, Tb{sup 3+}, and Mn{sup 2+} dopant ions which resulted in tunable photoluminescence. A broad violet/UV emission band of Ce{sup 3+} (350–425 nm) combined with blue-green emissions of Tb{sup 3+} (488 and 545 nm) and a yellow-orange emission of Mn{sup 2+} (560 nm) resulted in the observance of white light (x=0.31, y=0.32, T{sub C}=6624 K) under midwave UV excitation (300–340 nm). Energy transfer from Ce{sup 3+}→Tb{sup 3+} and Ce{sup 3+}→Mn{sup 2+} was confirmed by steady state and time-resolved emission spectra, lifetime, and quantum yield measurements. The structural properties, morphology, and elemental composition of the nanophosphors were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). -- Highlights: • White light-emitting multiphase silicate nanophosphors were prepared for the first time. • Multiple crystalline silicate phases were reproduced consistently by repeated syntheses. • Energy transfer from Ce{sup 3+}→Tb{sup 3+} and Ce{sup 3+}→Mn{sup 2+} was confirmed by PL, lifetime, and QY measurements.

  9. Assessing Hubbard-corrected AM05+U and PBEsol+U density functionals for strongly correlated oxides CeO2 and Ce2O3.

    Science.gov (United States)

    Weck, Philippe F; Kim, Eunja

    2016-09-29

    The structure-property relationships of bulk CeO2 and Ce2O3 have been investigated using AM05 and PBEsol exchange-correlation functionals within the frameworks of Hubbard-corrected density functional theory (DFT+U) and density functional perturbation theory (DFPT+U). Compared with conventional PBE+U, RPBE+U, PW91+U and LDA+U functionals, AM05+U and PBEsol+U describe experimental crystalline parameters and properties of CeO2 and Ce2O3 with superior accuracy, especially when +U is chosen close to its value derived by the linear-response approach. The present findings call for a reexamination of some of the problematic oxide materials featuring strong f- and d-electron correlation using AM05+U and PBEsol+U.

  10. Influence of the Ce:YAG Amount on Structure and Optical Properties of Ce:YAG-PMMA Composites for White LED

    Science.gov (United States)

    Armetta, Francesco; Sibeko, Motshabi A.; Luyt, Adriaan S.; Chillura Martino, Delia F.; Spinella, Alberto; Saladino, Maria Luisa

    2016-09-01

    Ce:YAG-poly(methyl methacrylate) (PMMA) composites were prepared by using a melt compounding method, adding several amounts of Ce:YAG in the range 0.1-5 wt. %. The optical properties of the obtained composites and of the composites combined with a blue LED were measured to investigate the effect of the amount of Ce:YAG on the resulting emitted light in view of possible application in white LED manufacture. An increase in Ce:YAG amount caused an increase in the emission and a shift of 15 nm, influencing the white LED performance. The structure and morphology of the composites were studied. The results show that the interaction between the two components, observed by using solid state NMR experiments, are the responsible for the observed shift.

  11. CeO2空心微球的制备与表征%Preparation and Characterization of CeO2 Hollow Spheres

    Institute of Scientific and Technical Information of China (English)

    吴秀勇; 王巍; 吕伟丽; 仉丽; 朱立平

    2007-01-01

    以PSA-A乳胶粒为模板,通过硫酸高铈和尿素的水解反应得到PSA/水合CeO2的核/壳结构的复合微球,通过煅烧除去乳胶粒模板得到立方相CeO2空心微球.CeO2空心微球平均粒径为450 nm~500 nm,由11.76 nm的小粒子堆积而成.考察了Ce4+、尿素、PVP的浓度,反应温度,PSA-A乳胶粒的加入量等实验条件对包覆效果的影响,通过FT-IR、XRD、TEM、SEM对样品进行了表征.

  12. 纳米CeO2粉体制备方法的研究进展%Prowess in Preparation of Nanometer CeO2

    Institute of Scientific and Technical Information of China (English)

    王瑞芬; 张胤

    2011-01-01

    综述了近年来国内外纳米CeO2粉体的几种主要制备方法及它们的研究进展,其中重点介绍了液相法及其特点,对纳米CeO2的制备技术和发展趋势进行了展望,并指出了今后应重点研究和解决的主要问题.%Several main methods and their progress of studies on the preparation of nanometer CeO2 in resent years were introduced in this paper. The liquid phase methods were reviewed in detail. The future trend of the preparation technology of nanometer CeO2 was predicted and the main problems which should be resolved in the future research were indicated too.

  13. 4d → 4f resonance in photoabsorption of cerium ion Ce3+ and endohedral cerium in fullerene complex {\\rm{Ce}}@{{{\\rm{C}}}_{82}}^{+}

    Science.gov (United States)

    Schrange-Kashenock, G.

    2016-09-01

    The theoretical investigation of the single-photoionization spectra in the 4d-resonance region (120-150 eV) for the ionic cerium Ce3+ and cerium in the endohedral complex {{Ce}}@{{{{C}}}82}+ (in practice, {{{Ce}}}3+@{{{{C}}}82}2-) is presented. The fullerene cage is modeled by ab initio spherical jellium shell with an accurate account for the real distribution of carbon electron density. The oscillator strengths are calculated within the multiconfiguration Dirac-Fock (MCDF) approach for phototransitions from the outermost shells of the ion Ce3+ with and without the influence of the potential generated by a fullerene cage. It is shown that the integrated oscillator strengths have the main contribution from the Ce3+ 4d → 4f (ten possible from the phototransitions {}2F{7/2,5/2}\\to {}2D{3/2,5/2},{}2F{5/2,7/2},{}2G{5/2,7/2}) resonance photoexcitations. The corresponding precise MCDF values for the oscillator strengths and the transition energies are presented for the first time. It is demonstrated that the resonance {f}4d\\to 4f oscillator strengths are slightly affected by the presence of the cage potential, despite the fact that the spectral levels structure is changed when the effect of this potential is included. The Auger 4d -1 decay from the cerium free ion Ce3+ and the encapsulated endohedral ion Ce3+@ are considered within the two-step model and the corresponding Lorentzian profiles are presented. This model clearly reveals the correspondence of the complex resonance profile in the Ce3+ photoabsorption to the fine structure of ion energy levels. The smoothing of the resonance profile in the photoabsorption of the endohedral system {{Ce}}@{{{{C}}}82}+ compared with the free ion Ce3+ is attributed to increasing the linewidths of the Auger transitions. This increase is estimated from the relevant experiment (Müller et al 2008 Phys. Rev. Lett. 101 133001) to be strong; as at least three times the value for an isolated ion. The presence of the confining fullerene

  14. CeO_2-supported vanadium oxide catalysts for soot oxidation:the roles of molecular structure and nanometer effect

    Institute of Scientific and Technical Information of China (English)

    刘坚; 赵震; 徐春明; 段爱军; 姜桂元

    2010-01-01

    The nanometer CeO2 powder was prepared by the method of microwave-assisted heating hydrolysis,and the nanometer CeO2-supported or ordinary CeO2-supported vanadia catalysts with different vanadium loadings(atomic ratios:100V/Ce=0.1,1,4,10,and 20) were prepared by an incipient-wetness impregnation method.Spectroscopic techniques(XRD,FT-IR,Raman and UV-Vis DRS) were utilized to characterize the structures of VOx/CeO2 catalysts.The results showed that the structures of CeO2-supported vanadium oxide catalysts de...

  15. Luminescence and scintillation properties of BaY2F8 : Ce3+, BaLu2F8 and BaLu2F8 : Ce3+

    NARCIS (Netherlands)

    van't Spijker, JC; Dorenbos, P; van Eijk, CWE; Jacobs, JEM; den Hartog, HW; Korolev, N

    1999-01-01

    Spectroscopic and scintillation properties of BaY2F8 :Ce3+, BaLu2F8 and BaLu2F8 :Ce3+ are presented. For pure BaLu2F8, a luminescence with a decay time of similar to 1 ns is observed under gamma-ray excitation. This luminescence with a light yield of about 200 ph/MeV is attributed to core-valence lu

  16. The influence of Mn-doped CeO2 on the activity of CuO/CeO2 in CO oxidation and NO + CO model reaction

    Science.gov (United States)

    Deng, Changshun; Huang, Qingqing; Zhu, Xiying; Hu, Qun; Su, Wenli; Qian, Junning; Dong, Lihui; Li, Bin; Fan, Minguang; Liang, Caiyuan

    2016-12-01

    This work is mainly focused on the investigation of the influence of Mn-doped CeO2 supported by CuO on the physicochemical and catalytic properties for CO oxidation and NO + CO model reaction. The obtained samples were characterized using N2-physisorption (BET), XRD, LRS, TEM, EDS-Mapping, ICP-AES, XPS, H2-TPR, O2-TPD, in situ DRIFTS, CO oxidation, and NO + CO model reaction. The results imply that appropriate doping MnOx into the lattice of CeO2 will cause an obvious change in the properties of the catalyst and the Cu/CeMn-10: 1 catalyst shows the largest specific surface area, the most uniformity of structure, and the most extent of lattice expansion. A few addition of MnOx is more conducive to the generation of low valence manganese ion in the process of calcination, which may contribute to the synergetic introduction. This further results in more Cu+ due to the shifting of redox equilibrium (Cu2+ + Ce3+ ↔ Cu+ + Ce4+) to right, as well as more oxygen vacancies. Moreover, the capability of Cu/CeMn-10: 1 on desorb/transform/decompose of the adsorbed NO species is more effective than that of Cu/CeO2. The results of catalytic performance show that Cu+/Cu0 species play a key role, and the activity is mainly related to the specific surface area, the content of Cu+ and Ce3+, the reduction, desorption capability of chemisorbed O2- (and/or O-) species as well as adsorption behaviors of these catalysts for CO oxidation and NO + CO reaction. Finally, possible reaction mechanisms are tentatively proposed to understand the reactions.

  17. Local character of the highest antiferromagnetic temperature of Ce systems in Sc-rich CeTi1 -xScxGe

    Science.gov (United States)

    Sereni, J. G.; Pedrazzini, P.; Gómez Berisso, M.; Chacoma, A.; Encina, S.; Gruner, T.; Caroca-Canales, N.; Geibel, C.

    2015-05-01

    The highest antiferromagnetic (AFM) temperature in Ce based compounds has been reported for CeScGe with TN=47 K , but its local or itinerant nature has not been deeply investigated yet. In order to shed more light into this unusually high ordering temperature we have investigated structural, magnetic, transport, and thermal properties of CeTi1 -xScxGe alloys within the range of stability of the CeScSi-type structure: 0.25 ≤x ≤1 . Along this concentration range, this strongly anisotropic system presents a complex magnetic phase diagram with a continuous modification of its magnetic behavior, from ferromagnetism for 0.25 ≤x ≤0.50 (with 7 K≤TC≤16 K ) to AFM for 0.60 ≤x ≤1 (with 19 K≤TN≤47 K ). The onset of the AFM phase is associated to a metamagnetic transition with a critical field increasing from Hcr=0 at x ≈0.55 to ≈6 T at x =1 , coincident with an increasing contribution of the first excited crystal electric field doublet. At a critical point xcr≈0.65 a second transition appears at TL≤TN . In contrast to observations in itinerant systems like CeRh2Si2 or CeRh3B2 , no evidences for significant hybridization of the 4 f electrons at large Sc contents were found. Therefore, the exceptionally large TN of CeScGe can be attributed to an increasing Ruderman-Kittel-Kasuya-Yosida interaction between Ce double layers as Sc content grows.

  18. Inhibitive effect of Ce(III) and La(III) cations for AA2219 aluminium alloy corrosion in sodium chloride medium

    Energy Technology Data Exchange (ETDEWEB)

    Venkatasubramanian, G., E-mail: venkatguru_1966@yahoo.co.in [Department of Chemistry, Sathyabama University, Jeppiaar Nagar, Chennai 600119 (India); Sheik Mideen, A. [Department of Chemistry, Sathyabama University, Jeppiaar Nagar, Chennai 600119 (India); Jha, Abhay K. [Materials Processing Division, Vikram Sarabhai Space Centre, Indian Space Research Organisation, Thiruvananthapuram 695022 (India); Kulandainathan, M. Anbu [Electro Organic Chemistry Division, Central Electrochemical Research Institute, Karaikudi 630006 (India)

    2014-11-14

    In this paper, the rare earth chlorides were used to mitigate the dealloying of Al{sub 2}Cu intermetallic particles in aluminium alloy 2219-T87 plate exposed to 0.6 M NaCl solution. The negative shift of cathodic branches of potentiodynamic polarisation curves revealed the cathodic inhibition towards intermetallic dealloying. The low and high frequency time constants obtained from electrochemical impedance spectra revealed an increase in the corrosion resistance due to precipitation of rare earth oxides/hydroxides on the porous surface of native oxide film of aluminium alloy. Scanning electron microscopy coupled with energy dispersive X-ray analysis and atomic force microscopy revealed that intermetallic inclusions are the sites for the formation of cerium and lanthanum deposits which suppress copper redeposition and minimise galvanic interactions between the matrix and Al{sub 2}Cu particles. - Graphical abstract: Scanning electron microscopy and atomic force microscopy reveal the intermetallic inclusions, the sites for the formation of cerium and lanthanum oxide/hydroxide precipitates which prevent intermetallic de-alloying, suppress copper redeposition and minimise galvanic interactions in aluminium alloy 2219-T87 plate. - Highlights: • Ce{sup 3+} and La{sup 3+} act as cathodic inhibitors for AA2219-T87 aluminium alloy in 0.6 M NaCl. • Al{sub 2}Cu intermetallic particles are the sites for the formation of Ce and La precipitates. • The decrease in surface potential by rare earth chlorides confirms their inhibition.

  19. The NA48 experiment

    CERN Multimedia

    1995-01-01

    The NA48 experiment is designed to study the Charge-Parity (CP) violation. CP violation is observed in certain very rare decays. Its study is important in understanding Nature's preference of matter over antimatter, which resulted in asymmetry soon after the Big Bang, creating a matter-dominated Universe.

  20. Riso na epilepsia

    Directory of Open Access Journals (Sweden)

    Edymar Jardim

    1967-06-01

    Full Text Available São estudados três casos de síndrome convulsiva temporal, com manifestações concomitantes de riso na sua fase inicial. As características principais foram a imotivação e á incoercibilidade do riso. Esses sintomas desapareceram com o uso de anticonvulsivantes.

  1. Biotecnologia na agricultura

    Directory of Open Access Journals (Sweden)

    Helaine Carrer

    2010-01-01

    Full Text Available A expectativa de o crescimento populacional atingir 9 bilhões de habitantes em 2050 em adição às questões da sustentabilidade e do aquecimento global nos desafiam a aumentar a oferta de alimentos. Uma metodologia alternativa que contribua para a redução do impacto desse cenário envolve a biotecnologia, que, nas últimas décadas, trouxe marcantes oportunidades tecnológicas na agricultura, resultando em relevante desenvolvimento na obtenção de novas variedades de plantas, na melhoria da qualidade de diversos alimentos e atualmente também na bioenergia. As técnicas biotecnológicas envolvendo os marcadores moleculares, a genômica e a transformação genética estão transformando a agricultura e são discutidas neste artigo.The expected population growth to reach 9 billion by 2050 in addition to issues of sustainability and global warming challenges us to increase the supply of food. An alternative approach to help reducing the impact of this scenario involves biotechnology which in recent decades has brought remarkable technological opportunities in the agriculture that resulted in relevant development in obtaining new plant varieties, improved quality of different foods, and now also in bioenergy. The biotechnology techniques involving molecular markers, genomics and genetic transformation are transforming agriculture and will be discussed in this article.

  2. Nonaqueous CE ESI-IT-MS analysis of Amaryllidaceae alkaloids.

    Science.gov (United States)

    Zhang, Yulin; Chen, Zilin

    2013-03-01

    The Amaryllidaceae are widely distributed medical plants. Lycorine, lycoramine, lycoremine, and lycobetaine are the major active alkaloids in Amaryllidaceae plants. A nonaqueous CE ESI-IT-MS method for separation, identification, and quantification of the Amaryllidaceae alkaloids has been developed. The MS(1-3) behavior has been studied and the fragmentation pathways of main fragment ions have been proposed. The effects of several factors such as composition and concentration of buffer, applied voltage, composition, and flow rate of the sheath liquid, nebulizing gas pressure, flow rate, and temperature of drying gas were investigated. Under the optimal conditions, the linear concentration range of these compounds was wide with the correlation coefficient (R(2) ) >0.99. RSDs of migration time and peak areas were alkaloids in the Lycoris radiata roots.

  3. CE-MS of antihistamines using nonvolatile phosphate buffer.

    Science.gov (United States)

    Chien, Chiu-Tang; Li, Fu-An; Huang, Ju-Li; Her, Guor-Rong

    2007-05-01

    Antihistamines were analyzed by CE-ESI-MS using phosphate buffer. The separation was performed in an acidic environment so that phosphate ions had a net velocity flowing toward the inlet reservoir instead of the ESI source. To further reduce the effect of ion suppression, the sodium ion in sodium phosphate was replaced with an ammonium ion. Furthermore, with the combination of reducing the concentration of acid added to the sheath liquid and the use of a low-flow interface, phosphoric acid could be added to the sheath liquid. Because of the use of the same counterion (phosphate ion) in running buffer and in sheath liquid, the separation integrity (resolution, elution order, and peak shape) was preserved. In addition, ion suppression was also greatly alleviated because a minimal amount of phosphate flowed into the ESI source.

  4. Chapitre I. Le toucher de bonne grâce

    OpenAIRE

    Jamain, Claude

    2016-01-01

    Jusqu’au milieu du xviiie siècle, le rapport entre un homme et un instrument de musique – c’est-à-dire l’art de faire résonner les cordes, ce qu’on appelle aujourd’hui le jeu – fut signifié par le mot de « toucher », principalement pour les claviers. Ensuite, « jouer » ou « jouer de » s’imposèrent. « Toucher » se trouve bien sûr dans L’Art de toucher le clavecin (1717) de François Couperin, et dans De la méchanique des doigts sur le clavessin (1724 puis 1731) de Jean-Philippe Rameau. Toucher ...

  5. Study protocol of the CHOiCE trial

    DEFF Research Database (Denmark)

    Nielsen, Mette Tranberg; Bech, Bodil Hammer; Blaakær, Jan;

    2016-01-01

    BACKGROUND: The effectiveness of cervical cancer screening programs is challenged by suboptimal participation and coverage. Offering cervico-vaginal self-sampling for human papillomavirus testing (HPV self-sampling) to non-participants can increase screening participation. However, the effect......-up testing at 30, 60, or 90 days after mail out of the results. DISCUSSION: The CHOiCE trial will provide strong and important evidence allowing us to determine if and how HPV self-sampling can be used to increase participation in cervical cancer screening. This trial therefore has the potential to improve...... varies substantially among studies, especially depending on the approach used to offer HPV self-sampling. The present trial evaluates the effect on participation in an organized screening program of a HPV self-sampling kit mailed directly to the home of the woman or mailed to the woman's home on demand...

  6. Observation of a Collective Oblate Band in 137Ce

    Institute of Scientific and Technical Information of China (English)

    ZHU Sheng-Jiang; Jon Myang-Gil; WEN Shu-Xian; WU Xiao-Guang; LIU Xiang-An; ZHU Ling-Yan; LI Ming; GAN Cui-Yun; M. Sakhaee; YANG Li-Ming; ZHANG Zheng; JIANG Zhuo; LONG Gui-Lu

    2000-01-01

    High spin states in 137 Ce have been studied by using the heavy-ion induced reaction 124Sn(18 O, 5n) carried out at China Institute of Atomic Energy. Partial level scheme with spin up to (43/2-), including a high spin collective rotational band observed for the first time, has been established. The collective band shows the properties similar to those oblate bands with γ ~-60° in neighboring nuclei and probably originates from the five quasi-particle configuration νs1/2 [vh11/2]2 π97/2 πh11/2. The characteristics of this oblate band have been discussed.

  7. The order parameter symmetry in CeIrIn5

    Directory of Open Access Journals (Sweden)

    H Shakeripour

    2016-06-01

    Full Text Available To understand the mechanism of superconductivity in unconventional super onductors is one of the big challenges in the field of superconductivity. Based on the BCS theory, there is a direct relation between the pairing mechanism and the symmetry of the order parameter. Therefore, identification of the structure of the superconducting gap or the order parameter provides key information on the pairing mechanism. The s-wave conventional superconductors have full point symmetry of the crystal lattice, thus they have full gap symmetry around the Fermi surface. This leads to the exponential temperature dependence of many physical properties in the superconducting state at low temperature. However, the presence of nodes imposed by symmetry in the gap function of unconventional superconductors implies a different order parameter other than conventional s-wave, which may lead to a different pairing mechanism. Here, we show how thermal conductivity measurements in CeIrIn5 at very low temperatures detect the superconducting gap structure.

  8. Ce que nous apprend le Numérique

    OpenAIRE

    Ben Abdallah, Nabil

    2017-01-01

    Ce que nous apprend le numérique Les technologies numériques ne cessent d’évoluer et de se diversifier provoquant des changements importants non seulement dans notre manière d’agir sur les objets du monde mais aussi dans notre rapport à soi, aux autres et même à nos machines classiques qui sont désormais des « objets connectés ». Ces changements sont si profonds qu’il est aujourd’hui difficile de mesurer leur ampleur et leur portée, certes par manque de méthodes fiables d’observation mais, et...

  9. Qu'est-ce que la relativité ?

    CERN Document Server

    Vannucci, François

    2005-01-01

    Publiée en 1905 par Albert Einstein, la théorie de la relativité marqua profondément le XXe siècle. Ce que tout un chacun sait… sans jamais avoir bien compris pourquoi ! François Vannucci commence donc par nous décrypter E=mc2. Car cette fameuse formule résume la révolution qu’apporta la théorie : énergie et masse ne sont plus des quantités indépendantes, elles sont reliées par la vitesse de la lumière. Il nous explique alors en quoi la théorie de la relativité, en établissant le cadre d’une théorie globale de l’univers - une cosmologie -, a révolutionné notre compréhension de l’univers…

  10. COMPARISION OF THE COLOR PROPERTIES OF COMPOUNDS Ln2Ce2O7 AND Ln2CeZrO7

    Directory of Open Access Journals (Sweden)

    B. Hablovicova

    2015-09-01

    Full Text Available Pyrochlore type pigments Ln2Ce2O7 and Ln2CeZrO7 (Ln = Nd, Sm, Gd, Dy, Er, Yb and Y prepared by solid-state reaction were investigated. Effect of rare earths and zirconium ions and calcination temperature (1400, 1500 and 1600oC for Ln2Ce2O7 and 1400, 1450 and 1500 C for Ln2CeZrO7 on their color properties in organic matrix and ceramic glazes, particle size distribution and phase composition were evaluated. The most interesting shades achieve compounds with the highest calcination temperature. Their colors depend on used rare earth ions (shades change from green, cross yellow to pink in organic mass and from green, cross yellow-green to orange in ceramic glazes, while compounds without zirconium have better color properties. Pigments Ln2Ce2O7 calcined at 1600 C are single-phase (except Yb2Ce2O7.

  11. The Interplay of Fe and Ce Magnetism in Ca0.71 Ce0.29(Fe1-xCox)As2 single crystals

    Science.gov (United States)

    Jiang, Shan; Liu, Lian; Cao, Huibo; Tian, Wei; Emmanuelidu, Eve; Shi, Aoshuang; Uemura, Yasutomo; Ni, Ni

    In this talk, we will present the synthesis and characterization of the Ca0.71 Ce0.29(Fe1-xCox)As2 single crystals. Elastic neutron scattering complemented by resistivity, susceptibility and heat capacity measurements has revealed a paramagnetic-to-antiferromagnetic phase transition of the Fe sublattice at 69K and a monoclinic-to-triclinic structural phase transition at 73 K in Ca0.71 Ce0.29FeAs2. In addition, Fe spin reorientation and Ce ordering at lower temperatures, reminiscent of the one in REFeAsO (RE=Ce, Pr, Nd) materials, exist. The Co substitution on the Fe sites completely suppresses the ordering of Fe sublattice at x=0.032. However, it only slightly affects the Ce ordering, which prevents the formation of superconductivity in Ca0.71 Ce0.29(Fe1-xCox)As2. Work at UCLA was supported by the NSF DMREF DMR-1435672. Work at Columbia and TRIUMF was supported by the NSF DMREF DMR- 1436095, PIRE project IIA 0968226 and DMR-1105961. Work at ORNL's High Flux Isotope Reactor was sponsored by DOE.

  12. Active sites over CuO/CeO2 and inverse CeO2/CuO catalysts for preferential CO oxidation

    Science.gov (United States)

    Zeng, Shanghong; Wang, Yan; Ding, Suping; Sattler, Jesper J. H. B.; Borodina, Elena; Zhang, Lu; Weckhuysen, Bert M.; Su, Haiquan

    2014-06-01

    A series of CuO/CeO2 and inverse CeO2/CuO catalysts are prepared by the surfactant-templated method and characterized via XRD, HRTEM, H2-TPR, SEM, XPS, in situ XRD, in situ UV-Vis and N2 adsorption-desorption techniques. It is found that there are two kinds of surface sites in the CuO-CeO2 system, including CuO surface sites for CO chemisorption and CeO2 surface sites with oxygen vacancies for oxygen sorption. The active sites for CO oxidation are located on the contact interface of two-kind surface sites and the lattice oxygen can make a significant contribution to the CO-PROX reaction. The resistance to H2O and CO2 is related to BET surface area, the crystallite sizes of CuO and the reduction behavior of catalysts. The Ce4Cu4 and Ce4Cu1 catalysts exhibit the best resistance against H2O and CO2.

  13. Dielectric Properties of CeO2 -Doped Ba( Zr, Ti)O3 Ceramics

    Institute of Scientific and Technical Information of China (English)

    Huang Xinyou; Gao chunhua; Chen Xiangchong; Liu Huiping; Huang Guojun; Zheng Xialian

    2004-01-01

    The influence of additive amount of CeO2 on the properties of Ba(Ti, Zr)O3 (BTZ) capacitor ceramics prepared using conventional solid-state reaction method was investigated. The dielectric constant(ε) increases to a maximum when w( CeO2 ) is about 1.0% and then decreases again at higher doping concentration of CeO2. The dielectric constant gets a maximum while w ( CeO2 ) is about 1. 0%, and the dielectric loss is minimum while w ( CeO2 ) is0.5 %. CeO2 can decrease the curie temperature, widen the εr-T peak and decrease the absolute value of dielectric constant temperature coefficient. The influence mechanism of CeO2 additive on the properties of the BTZ ceramics was discussed. The results show that CeO2 additive influences the properties of BTZ ceramics by means of forming defect solid solution , shifting curie temperature peak effect, segregating in crystal boundary , and impeding grain growth.

  14. Catalytic Oxidative Properties and Characterization of CuO/CeO2 Catalysts

    Institute of Scientific and Technical Information of China (English)

    蒋晓原; 周仁贤; 袁骏; 吕光烈; 郑小明

    2003-01-01

    The oxidative properties and characterization of CuO, CeO2 and CuO/CeO2 catalysts were examined by means of a CO micro-reactor GC system, TPR, XPS and X-ray diffraction Rietveld methods. The results show that either CuO or CeO2 activity is quite low for CO oxidation. However, when CuO and CeO2 are mixed, the oxidative activity of the catalyst increases significantly, probably owing to the valency status of copper species (Cu2+ and Cu+) on the CeO2 surface, the dispersion and reducibility. XPS surface analysis shows that CuO loading is very important in forming of either Cu2+ or Cu+. Rietveld analysis shows that some CuO, which has smaller ion radius than Ce4+, enters the CeO2 lattice after CuO and CeO2 are mixed. When the CuO loading reaches 5.0%, the size of CuO crystals is a minimum (6.1 nm) and the micro-strain value is a maximum (2.86×10-3), resulting in high surface energy and the best activity for CO oxidation.

  15. File list: Oth.CeL.10.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.10.Clamp.AllCell dm3 TFs and others Clamp Cell line SRX159170,SRX159172,SRX...159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.10.Clamp.AllCell.bed ...

  16. File list: Oth.CeL.20.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.20.Clamp.AllCell dm3 TFs and others Clamp Cell line SRX159172,SRX159170,SRX...159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.20.Clamp.AllCell.bed ...

  17. File list: Oth.CeL.05.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.05.Clamp.AllCell dm3 TFs and others Clamp Cell line SRX159172,SRX159170,SRX...159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.05.Clamp.AllCell.bed ...

  18. File list: Oth.CeL.10.Dref.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.10.Dref.AllCell dm3 TFs and others Dref Cell line SRX749042,SRX749043,SRX17...0984,SRX170983,SRX170986,SRX170985 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.10.Dref.AllCell.bed ...

  19. File list: Oth.CeL.05.Dref.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.05.Dref.AllCell dm3 TFs and others Dref Cell line SRX749042,SRX170984,SRX74...9043,SRX170983,SRX170986,SRX170985 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.05.Dref.AllCell.bed ...

  20. File list: Oth.CeL.20.Dref.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  1. File list: Oth.CeL.50.Dref.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.50.Dref.AllCell dm3 TFs and others Dref Cell line SRX170984,SRX749042,SRX74...9043,SRX170983,SRX170985,SRX170986 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.50.Dref.AllCell.bed ...

  2. File list: Oth.CeL.20.Ice1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.20.Ice1.AllCell dm3 TFs and others Ice1 Cell line SRX306193,SRX306196,SRX30...6190,SRX097616 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.20.Ice1.AllCell.bed ...

  3. File list: Oth.CeL.05.Ice1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.05.Ice1.AllCell dm3 TFs and others Ice1 Cell line SRX097616,SRX306190,SRX30...6196,SRX306193 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.05.Ice1.AllCell.bed ...

  4. File list: Oth.CeL.10.Ice1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.10.Ice1.AllCell dm3 TFs and others Ice1 Cell line SRX306190,SRX306193,SRX30...6196,SRX097616 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.10.Ice1.AllCell.bed ...

  5. File list: Oth.CeL.50.Ice1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.50.Ice1.AllCell dm3 TFs and others Ice1 Cell line SRX097616,SRX306193,SRX30...6190,SRX306196 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.50.Ice1.AllCell.bed ...

  6. File list: Oth.CeL.20.Epitope_tags.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.20.Epitope_tags.AllCell dm3 TFs and others Epitope tags Cell line SRX099638...099636 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.20.Epitope_tags.AllCell.bed ...

  7. CeO2 nanorods-supported transition metal catalysts for CO oxidation.

    Science.gov (United States)

    Mock, Samantha A; Sharp, Shannon E; Stoner, Thomas R; Radetic, Michael J; Zell, Elizabeth T; Wang, Ruigang

    2016-03-15

    A catalytically active oxide support in combination with metal catalysts is required in order to achieve better low temperature activity and selectivity. Here, we report that CeO2 nanorods with a superior surface oxygen release/storage capability were used as an active support of transition metal (TM) catalysts (Mn, Fe, Co, Ni, Cu) for CO oxidation reaction. The as-prepared CeO2 nanorods supported 10 wt% TM catalysts were highly active for CO oxidation at low temperature, except for the Fe sample. It is found that the 10%Cu-CeO2 catalyst performed best, and it provided a lower light-off temperature with T50 (50% conversion) at 75 °C and T100 (100% conversion) of CO to CO2 at 194 °C. The atomic level surface structure of CeO2 nanorods was investigated in order to understand the improved low temperature catalytic activity. The richness of surface roughness and various defects (voids, lattice distortion, bending, steps, twinning) on CeO2 nanorods could facilitate oxygen release and storage. According to XRD and Raman analysis, copper species migrate into the bulk CeO2 nanorods to a greater degree. Since CO adsorbed over the surface of the catalyst/support is detrimental to its catalytic activity, the surface defects on the CeO2 nanorods and CeO2-TM interactions were critical to the enhanced activity.

  8. Size effect of Raman scattering on CeO2 nanocrystal by hydrothermal method

    Science.gov (United States)

    Hattori, Takashi; Kobayashi, Katsutoshi; Ozawa, Masakuni

    2017-01-01

    In this study, we prepared surface-modified CeO2 nanocrystals (NCs) by a hydrothermal method, and calcined CeO2 NCs at various temperatures between 400 and 1000 °C for 3 h in air to obtain crystal-size-controlled CeO2 NCs. We investigated the correlation between the Raman spectra and the crystal sizes of the CeO2 powder. The peak position of the F2g mode of CeO2 was shifted to lower energies as the crystal size decreased and the peak broadened. The present hydrothermally driven CeO2 NCs showed no change in lattice constant depending on crystal size after heat treatment. The Raman peak position of the F2g mode as a function of inverse CeO2 crystal size corresponded to the models for phonon confinement without the combination of strain and defect effects. Moreover, it was also suggested that the Raman peak width of CeO2 NCs without strain also showed dependence on particle size.

  9. Surface reaction network of CO oxidation on CeO2/Au(110) inverse model catalysts.

    Science.gov (United States)

    Ding, Liangbing; Xiong, Feng; Jin, Yuekang; Wang, Zhengming; Sun, Guanghui; Huang, Weixin

    2016-11-30

    CeO2/Au(110) inverse model catalysts were prepared and their activity toward the adsorption and co-adsorption of O2, CO, CO2 and water was studied by means of X-ray photoelectron spectroscopy, low energy electron diffraction, thermal desorption spectra and temperature-programmed reaction spectra. The Au surface of CeO2/Au(110) inverse model catalysts molecularly adsorbs CO, CO2 and water, and the polycrystalline CeO2 surface of CeO2/Au(110) inverse model catalysts molecularly adsorbs O2, and molecularly and reactively adsorbs CO, CO2 and water. By controllably preparing co-adsorbed surface species on CeO2/Au(110) inverse model catalysts, we successfully identified various surface reaction pathways of CO oxidation to produce CO2 with different barriers both on the CeO2 surface and at the Au-CeO2 interface, including CO oxidation by various oxygen species, and water/hydroxyl group-involved CO oxidation. These results establish a surface reaction network of CO oxidation catalyzed by Au/CeO2 catalysts, greatly advancing the fundamental understandings of catalytic CO oxidation reactions.

  10. Effect of the Addition of CeO2 to Iron Phosphate Glass for Catalytic Applications.

    Science.gov (United States)

    Chung, Jae-Yeop; Kim, Jong-Hwan; Choi, Su-Yeon; Ryu, Bong-Ki

    2015-10-01

    We investigated the effect of CeO2 content on the catalytic behavior and chemical properties of the (100 - x)(80P2O5-20Fe2O3)-xCeO2 (x = 0, 4, 8, 12, 16, 20 and 24 wt%) glass system. Using thermogravimetric analysis, we confirmed that the catalytic activity increased until a CeO2 content of 16 wt%, beyond which, it decreased. The reasons for the change in the catalytic properties of the glass samples were determined using Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and density analyses. It was confirmed using the FT-IR and XPS-01s spectra that CeO2 acts as a network modifier in iron phosphate glass. When the CeO2 content is above 16 wt%, the number of non-bridging oxygen atoms decreases with increasing CeO2 content. For these reasons, the catalytic properties decrease when the CeO2 content is more than 16 wt%. From the dissolution rate measurements, it can be observed that cerium-iron phosphate has a high water resistance. Also, as we expected, it can be confirmed that the chemical durability is improved with increasing CeO2 content.

  11. CeO2 as insulation layer in HTc superconducting multilayer and cross over structures

    NARCIS (Netherlands)

    Wijck, van M.A.A.M.; Verhoeven, M.A.J.; Reuvekamp, E.M.C.M.; Gerritsma, G.J.; Blank, D.H.A.; Rogalla, H.

    1996-01-01

    We present a study of the electrical properties of insulating CeO2 layers in combination with superconducting (Y/Dy) Ba2Cu3O7-delta (RBCO) films over ramps and in crossover structures. CeO2 is frequently used as a buffer layer, or template layer for biepitaxial grain boundary junctions, but can als

  12. Design of an ultrasmall Au nanocluster-CeO2 mesoporous nanocomposite catalyst for nitrobenzene reduction.

    Science.gov (United States)

    Chong, Hanbao; Li, Peng; Xiang, Ji; Fu, Fangyu; Zhang, Dandan; Ran, Xiaorong; Zhu, Manzhou

    2013-08-21

    In this work we are inspired to explore gold nanoclusters supported on mesoporous CeO2 nanospheres as nanocatalysts for the reduction of nitrobenzene. Ultrasmall Au nanoclusters (NCs) and mesoporous CeO2 nanospheres were readily synthesized and well characterized. Due to their ultrasmall size, the as-prepared Au clusters can be easily absorbed into the mesopores of the mesoporous CeO2 nanospheres. Owing to the unique mesoporous structure of the CeO2 support, Au nanoclusters in the Au@CeO2 may effectively prevent the aggregation which usually results in a rapid decay of the catalytic activity. It is notable that the ultrasmall gold nanoclusters possess uniform size distribution and good dispersibility on the mesoporous CeO2 supports. Compared to other catalyst systems with different oxide supports, the as-prepared Au nanocluster-CeO2 nanocomposite nanocatalysts showed efficient catalytic performance in transforming nitrobenzene into azoxybenzene. In addition, a plausible mechanism was deeply investigated to explain the transforming process. Au@CeO2 exhibited efficient catalytic activity for reduction of nitrobenzene. This strategy may be easily extended to fabricate many other heterogeneous catalysts including ultrasmall metal nanoclusters and mesoporous oxides.

  13. File list: Oth.CeL.10.Epitope_tags.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.10.Epitope_tags.AllCell dm3 TFs and others Epitope tags Cell line SRX099635...099636 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.10.Epitope_tags.AllCell.bed ...

  14. Influence of microgravity on Ce-doped Bi12SiO20 crystal defect

    Indian Academy of Sciences (India)

    Y F Zhou; J Y Xu; Y Liu; L D Chen; Y Y Huang; W X Huang

    2007-06-01

    Space grown BSO crystal doped with Ce was characterized by means of X-ray fluorescence spectra, X-ray topography, dislocation density etc. Influence of microgravity on Ce-doped BSO crystal defect was studied by comparing space grown BSO crystal with ground grown one. These results show that compositional homogeneity and structural perfection of crystal can be improved under microgravity conditions.

  15. File list: Oth.CeL.10.dm.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.10.dm.AllCell dm3 TFs and others dm Cell line SRX160967,SRX160968,SRX335496...,SRX495787,SRX495790,SRX495786,SRX335495 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.10.dm.AllCell.bed ...

  16. Magnetic Phase Transitions of CeSb. II: Effects of Applied Magnetic Fields

    DEFF Research Database (Denmark)

    Meier, G.; Fischer, P.; Hälg, W.;

    1978-01-01

    For pt.I see ibid., vol.11, p.345 (1978). The metamagnetic phase transition and the associated phase diagram of the anomalous antiferromagnet CeSb were determined in a neutron diffraction study of the magnetic ordering of CeSb single crystals in applied magnetic fields parallel to the (001...

  17. Electromagnetic and Microwave-Absorbing Properties of Plate-Like Nd-Ce-Fe Powder

    Science.gov (United States)

    Qiao, Ziqiang; Pan, Shunkang; Xiong, Jilei; Cheng, Lichun; Lin, Peihao; Luo, Jialiang

    2016-09-01

    Plate-like Ce x Nd2-x Fe17 (x = 0.0, 0.1, 0.2, 0.3, 0.4) powders have been synthesized by an arc melting and high-energy ball milling method. The structure of the Nd-Ce-Fe powders was investigated by x-ray diffraction analysis. Their morphology and particle size distribution were evaluated by scanning electron microscopy and laser particle analysis. The saturation magnetization and electromagnetic parameters of the powders were characterized using vibrating-sample magnetometry and vector network analysis, respectively. The results reveal that the Ce x Nd2-x Fe17 (x = 0.0, 0.1, 0.2, 0.3, 0.4) powders consisted of Nd2Fe17 single phase with different Ce contents. The particle size and saturation magnetization decreased with increasing Ce content. The resonant frequencies of ɛ″ and μ″ moved towards lower frequency with increasing Ce concentration. The minimum reflection loss value decreased as the Ce content was increased. The minimum reflection loss and absorption peak frequency of Ce0.2Nd1.8Fe17 with coating thickness of 1.8 mm were -22.5 dB and 7 GHz, respectively. Increasing the values of the complex permittivity and permeability could result in materials with good microwave absorption properties.

  18. Chiral Separation of Erythromycin as a New Chiral Selector on CE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Erythromycin as a new chiral selector was first used for chrial separation of four derivatives of biphenyldimethylester enantiomers on CE. The influence of pH, the chiral selector concentration and organic modifiers were preliminarily studied. Experiments show that the erythromycin as chiral selector is useful to CE.

  19. Photocatalytic and antibacterial properties of phytosynthesized CeO2 NPs using Moringa oleifera peel extract.

    Science.gov (United States)

    Surendra, T V; Roopan, Selvaraj Mohana

    2016-08-01

    Biosynthetic methods are alternative approaches which are much safer than the normal techniques (physical and chemical) used for the methods for synthesis of metal nanoparticles. The benefits are sample as it is economic and environment friendly. Herein present investigation, we have reported a microwave mediated eco-friendly synthetic approach for preparing cerium oxide (CeO2) nanoparticles. Here, we used Moringa oleifera peel as the stabilizing and reducing agent towards synthesize of Ce2O NPs via microwave irradiation. The NPs were further characterized using UV-Vis, FT-IR, XRD and HR-TEM techniques. The FTIR analysis confirmed the phytochemical involvement in NPs stabilization. The crystallinity of CeO2 nanoparticles are well demonstrated through X-ray Diffraction and HR-TEM. The TEM images reveal the spherical shape of the CeO2 NPs having an average size of 45nm. Additionally, these CeO2 NPs were used successfully as a catalyst in the degradation of the dye, crystal violet. Also the antibacterial activity of the synthesized CeO2 NPs was evaluated using Staphylococcus aureus (Gram positive bacteria) and Escherichia coli (Gram negative bacteria). CeO2 NPs showed better activity on E. coli than S. aureus. We have demonstrated an eco-friendly preparation of CeO2 nanoparticles, a good photocatalyst and having better antibacterial properties.

  20. File list: ALL.CeL.05.AllAg.Kc167 [Chip-atlas[Archive

    Lifescience Database Archive (English)

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