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Sample records for ce na korrozionnye

  1. Formation of Broensted acids sites in the reaction of cyclohexanol on NaCeY zeolites

    International Nuclear Information System (INIS)

    Vogt, O.; Nattich, M.; Datka, J.; Gil, B.

    2002-01-01

    This study was undertaken to elucidate why the catalytic activity of NaCeY in cyclohexanol reactions carried out in a pulse reactor increases with the pulse number. We studied therefore the effect of cyclohexanol and also of ethanol and water on catalytic activity NaCeY (of exchange degrees 36 and 72%) in cyclohexanol reactions: isomerization and disproportionation. We also studied the reaction of cyclohexanol and water with NaCeY zeolite by IR spectroscopy. Our results evidenced that new Broensted acid sites were formed by the reaction of cyclohexanol and water. This was shown by IR spectroscopy: the increase of Si-O 1 H-Al band 3638 cm -1 and in increase of ammonium ions band (upon ammonia adsorption). The new sites were formed by hydrolysis of Ce 3+ ions with water introduced in a pulse, or produced by dehydration of cyclohexanol catalyzed by acid sites. Formation of new Broensted acid sites resulted in an increase of catalytic activity of NaCeY in cyclohexane reaction as observed in this study and also in cyclohexanol reactions. (author)

  2. Growth and luminescent properties of the Ce, Pr doped NaCl single crystals grown by the modified micro-pulling-down method

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, Yuui, E-mail: y-yokota@tagen.tohoku.ac.j [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University/2-1-1, Katahira, Aoba-ku, Sendai (Japan); Yanagida, Takayuki; Fujimoto, Yutaka [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University/2-1-1, Katahira, Aoba-ku, Sendai (Japan); Nikl, Martin [Institute of Physics, Academy of Sciences of the Czech Republic/6253, Prague (Czech Republic); Yoshikawa, Akira [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University/2-1-1, Katahira, Aoba-ku, Sendai (Japan); New Industry Creation Hatchery Center (NICHe), Tohoku University/2-1-1, Katahira, Aoba-ku, Sendai (Japan)

    2010-03-15

    We have investigated luminescent properties of nondope, Ce and Pr doped NaCl [nondope NaCl, Ce:NaCl, Pr:NaCl] single crystals grown by a modified micro-pulling-down method with a removable chamber system. Nondope, Ce 1% and Pr 1% doped NaCl crystals with a single phase of NaCl structure were obtained and the crystals indicated general crystal quality by the X-ray rocking curve measurement. For the nondope NaCl and Pr:NaCl crystals, the transmittance spectra indicated almost more than 60% in the wavelength from 200 to 800 nm and an absorption of Ce{sup 3+} ion was observed in the transmittance spectrum of Ce:NaCl crystal. The emission spectrum originated from Ce{sup 3+} 5d-4f transition appeared around 300 nm in the photoluminescence spectrum and the decay time was 19.7 ns.

  3. Growth and luminescent properties of the Ce, Pr doped NaCl single crystals grown by the modified micro-pulling-down method

    International Nuclear Information System (INIS)

    Yokota, Yuui; Yanagida, Takayuki; Fujimoto, Yutaka; Nikl, Martin; Yoshikawa, Akira

    2010-01-01

    We have investigated luminescent properties of nondope, Ce and Pr doped NaCl [nondope NaCl, Ce:NaCl, Pr:NaCl] single crystals grown by a modified micro-pulling-down method with a removable chamber system. Nondope, Ce 1% and Pr 1% doped NaCl crystals with a single phase of NaCl structure were obtained and the crystals indicated general crystal quality by the X-ray rocking curve measurement. For the nondope NaCl and Pr:NaCl crystals, the transmittance spectra indicated almost more than 60% in the wavelength from 200 to 800 nm and an absorption of Ce 3+ ion was observed in the transmittance spectrum of Ce:NaCl crystal. The emission spectrum originated from Ce 3+ 5d-4f transition appeared around 300 nm in the photoluminescence spectrum and the decay time was 19.7 ns.

  4. Bimodal Fluorescence and Magnetic Resonance Imaging Using Water-Soluble Hexagonal NaYF4:Ce,Tb,Gd Nanocrystals

    Directory of Open Access Journals (Sweden)

    Wen Ting Ren

    2011-01-01

    Full Text Available The present study explored the feasibility of using hexagonal-phase NaYF4:Ce,Tb,Gd nanocrystals as bimodal probes for fluorescence and magnetic resonance (MR imaging. Using a facile and user-friendly strategy, the NaYF4:Ce,Tb,Gd nanocrystals were synthesized with good water dispensability, high quantum yield (26%, and decent MR T1 relaxivity (r1=2.87 mM−1 s−1. The NaYF4:Ce,Tb,Gd NCs conjugated by folic acid presented great efficiency in fluorescence imaging of C6 glioma cells in vitro. Meanwhile, in in vivo MR experiments on rats, the NaYF4:Ce,Tb,Gd NCs also significantly increased T1 signal in the liver, spleen, and kidney even with a low probe dose. The proposed NaYF4:Ce,Tb,Gd nanoprobes hold promise for simultaneous bimodal fluorescence and MR bioimaging.

  5. 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

    2017-07-01

    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+.

  6. 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.

  7. Preparation and emission properties of NaBi(WO4)2 and NaBi(WO4)2:Ce single crystals

    International Nuclear Information System (INIS)

    Nitsch, K.; Nikl, M.; Barta, C.; Triska, A.

    1990-01-01

    The preparation of pure and Ce 3+ -doped NaBi(WO 4 ) 2 single crystals (NBW) and the determination of their basic transmission and emission properties including time-resolved measurements are described. The decay of NBW emission is obviously non-exponential. It can be concluded that emission arises at regular sites of the crystal lattice and is connected with electronic transitions from Bi 3+ to the WO 4 2- group and/or excitation of the WO 4 2- group itself. It is not possible to excite Ce 3+ ions directly

  8. Structural relaxation of scintillating Ce doped NaGd(PO.sub.3./sub.).sub.4./sub. glass

    Czech Academy of Sciences Publication Activity Database

    Chromčíková, M.; Rodová, Miroslava; Nitsch, Karel; Liška, M.

    2010-01-01

    Roč. 102, č. 3 (2010), 961-964 ISSN 1388-6150 R&D Projects: GA AV ČR KAN300100802 Institutional research plan: CEZ:AV0Z10100521 Keywords : structural relaxation * Tool-Narayanaswamy-Mazurin model * thermo-mechanical analysis * Ce:NaGd(PO 3 ) 4 glass * dynamic viscosity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.752, year: 2010

  9. Synthesis, structure and properties of bimetallic sodium rare-earth (RE) borohydrides, NaRE(BH4)4, RE = Ce, Pr, Er or Gd

    DEFF Research Database (Denmark)

    Payandeh Gharibdoust, Seyedhosein; Ravnsbæk, Dorthe B.; Černý, Radovan

    2017-01-01

    Formation, stability and properties of new metal borohydrides within RE(BH4)3-NaBH4, RE = Ce, Pr, Er or Gd is investigated. Three new bimetallic sodium rare-earth borohydrides, NaCe(BH4)4, NaPr(BH4)4 and NaEr(BH4)4 are formed based on an addition reaction between NaBH4 and halide free rare-earth...... to formation of metal hydrides and possibly slower formation of sodium borohydride. The dehydrogenated state clearly contains rare-earth metal borides, which stabilize boron in the dehydrogenated state....

  10. Realizace víceúčelového serveru na bázi WINDOWS

    OpenAIRE

    Depiak, Petr

    2008-01-01

    Práce je věnována poznatkům o síťových službách, které se často vyskytují na serverových systémech. Tyto služby zejména souvisí s úschovou, přenosem a interpretací dat. Jedná se o služby přenosu, které využívají protokoly FTP a SMB, kde jsou popsány jejich principy a možnosti zabezpečení. Následující část rozebírá problematiku elektronické pošty a vysvětluje její principy a možnosti nasazení. Popsány jsou její stěžejní protokoly SMTP, POP3 a IMAP. Důležitou část práce tvoří služba WWW využíva...

  11. 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.

  12. 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.

  13. Czynniki kliniczne wpływające na zachowania samobójcze w wybranych zaburzeniach psychicznych

    Directory of Open Access Journals (Sweden)

    Antoni Florkowski

    2015-10-01

    Full Text Available Zachowania samobójcze mające związek z występującymi zaburzeniami psychicznymi są od wielu lat przedmiotem badań naukowych. Samobójstwa stanowią poważny problem społeczny oraz medyczny. Światowa Organizacja Zdrowia ocenia, że w grupie wiekowej 15–44 lata jest to trzecia najczęstsza przyczyna zgonów. Samobójstwo to proces złożony, na który ma wpływ wiele czynników, zarówno powiązanych ze sobą, jak i niemających bezpośredniego związku. W pracy omówiono jedynie czynniki kliniczne, jakie mogą wystąpić w niektórych zaburzeniach psychicznych, najczęściej identyfikowanych z zachowaniami samobójczymi. Wśród zaburzeń psychicznych powodujących wysokie ryzyko suicydalne wymienia się depresję, zaburzenia osobowości, uzależnienie od alkoholu i  schizofrenię paranoidalną. Poszukiwanie czynników sprzyjających decyzjom samobójczym u pacjentów z tymi schorzeniami jest niezwykle ważne. Badania i obserwacje osób zagrożonych samobójstwem wskazują na pewne powtarzające się u nich charakterystyczne objawy oraz zachowania, niezależnie od rozpoznawanego zaburzenia psychicznego. W świetle przeprowadzonych badań uważa się, że istotny wpływ na wystąpienie zachowań samobójczych u osób z wymienionymi zaburzeniami psychicznymi mają następujące czynniki: próby samobójcze w wywiadzie, impulsywność i agresja, uporczywa bezsenność, przewlekłe stany depresyjne i subdepresyjne, objawy psychotyczne (urojenia prześladowcze i/lub depresyjne, omamy imperatywne. Można znacznie ograniczyć ryzyko samobójstwa poprzez umiejętne postępowanie diagnostyczne oraz właściwą ocenę czynników klinicznych.

  14. Blue-green tunable color of Ce(3+)/Tb(3+) coactivated NaBa3La3Si6O20 phosphor via energy transfer.

    Science.gov (United States)

    Jia, Zhen; Xia, Mingjun

    2016-09-15

    A series of color tunable phosphors NaBa3La3Si6O20:Ce(3+), Tb(3+) 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 Ce(3+) 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 Ce(3+) and Tb(3+) ions coactivated phosphors exhibit color tunable emission light from deep blue to green by adjusting the concentration of the Tb(3+) ions. An energy transfer of Ce(3+) → Tb(3+) investigated by the photoluminescence properties and lifetime decay, is demonstrated to be dipole-quadrupole interaction. These results indicate the NaBa3La3Si6O20:Ce(3+), Tb(3+) phosphors can be considered as potential candidates for blue-green components for white light emitting diodes.

  15. 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.

  16. Effects of A-Site (NaCe) Substitution with Na-Deficiency on Structures and Properties of CaBi4Ti4O15-Based High-Curie-Temperature Ceramics

    Science.gov (United States)

    Yan, Haixue; Li, Chengen; Zhou, Jiaguang; Zhu, Weimin; He, Lianxin; Song, Yuxin; Yu, Youhua

    2001-11-01

    Three kinds of bismuth-layer-structured ferroelectric (BLSF) ceramics, CaBi4Ti4O15 (CBT), Ca0.8(CeNa)0.1Bi4Ti4O15 (CNBT), and Na-deficient Ca0.8(Ce0.1Na0.05\\Box0.05)Bi4Ti4O15 [CN\\BoxBT] (where \\Box represents vacancies) were prepared by a conventional ceramic technique. X-ray powder diffraction showed that their crystal structures are a single phase of BLSF with m=4. Sintering characteristics of the three ceramics were also discussed. Scanning electron microscope (SEM) micrographs of CN\\BoxBT showed that the grain is platelike. The A-site (NaCe) substitution can improve the piezoelectric constant d33 and high-temperature resistivity with decreasing Curie temperature. The modification by A-site (NaCe) substitution with Na-deficiency is more pronounced than CNBT, which not only leads to a very high piezoelectric constant d33 and high-temperature resistivity but also increases the Curie temperature. The reason for the high Tc (Tc=866°C) of CN\\BoxBT is considered to be internal stress. As a result, Na-deficient CN\\BoxBT ceramic is found to be an excellent high-temperature piezoelectric material.

  17. Ãgua SubterrÃnea na Bacia Experimental de Aiuaba-CE

    OpenAIRE

    Josà Edberto da Silva

    2009-01-01

    A Bacia HidrogrÃfica Experimental de Aiuaba (BEA), està situada dentro da EstaÃÃo EcolÃgica de Aiuaba, no municÃpio de Aiuaba, Estado do CearÃ, portanto, livre da aÃÃo antrÃpica (fertilizantes, fontes de poluiÃÃo, impactos, etc). O fluxo subterrÃneo em meio poroso e fraturado à pouco conhecido na regiÃo. Para o seu estudo, foi realizado um levantamento geofÃsico utilizando o mÃtodo âVery Low Frequencyâ (VLF), para identificar os tipos de fraturas existentes nas rochas da regiÃo, como tambÃm p...

  18. Spectroscopic properties of Er:NaLa(WO{sub 4}){sub 2} crystals and effect of Ce codoping onto the excited state energy transformation in this crystal

    Energy Technology Data Exchange (ETDEWEB)

    Bonelli, L.; Cornacchia, F.; Tonelli, M. [NEST-INFM-CNR-Dipartimento di Fisica dell' Universit' a di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Lis, D.A., E-mail: lisdenis@mail.ru [A.M. Prokhorov General Physics Institute of Russian Academy of Science, Vavilova street 38, Moscow 119991 (Russian Federation); Subbotin, K.A.; Smirnov, V.A. [A.M. Prokhorov General Physics Institute of Russian Academy of Science, Vavilova street 38, Moscow 119991 (Russian Federation); Zharikov, E.V. [D.I. Mendeleyev University of Chemical Technology of Russia, Miusskaya Sq. 9, Moscow 125047 (Russian Federation)

    2013-03-15

    We report on the spectroscopic investigation of Erbium and Cerium co-doped Czochralski-grown NaLa(WO{sub 4}){sub 2} crystals. We measured the Er energy levels positions and calculated the Judd-Ofelt parameters as well as the radiative lifetimes and branching ratios for the transitions under investigation. The dynamics of population of the {sup 4}S{sub 3/2}, {sup 4}I{sub 11/2} and {sup 4}I{sub 13/2} multiplets of Er{sup 3+} was analyzed in order to determine the influence of the energy transfer mechanism Er-Ce onto the 1.5 {mu}m emission. The results of Er room temperature lifetimes measurements show that the {sup 4}I{sub 11/2} lifetime reduces significantly as the Ce concentration increases, starting from 183 {mu}s for the 0.4 at% Er doped sample to 15 {mu}s for the 16% Ce-codoped crystal. On the contrary, the lifetime of {sup 4}I{sub 13/2} Er state reduces simultaneously of only about 10%. The obtained results suggest the possibility to obtain efficient 1.5 {mu}m laser emission from NaLa(WO{sub 4}){sub 2}. - Highlights: Black-Right-Pointing-Pointer The Judd-Ofelt parameters of Er{sup 3+}:NaLa(WO){sub 4} crystal were calculated. Black-Right-Pointing-Pointer The values of Er energy levels in NaLa(WO){sub 4} crystal were presented. Black-Right-Pointing-Pointer The presence of Ce helps the population of the Er {sup 4}I{sub 13/2} excited state in NaLa(WO){sub 4}.

  19. Controllable upconversion luminescence and temperature sensing behavior in NaGdF4:Yb3+/Ho3+/Ce3+ nano-phosphors

    Science.gov (United States)

    Pang, Tao; Wang, Jiajun

    2018-01-01

    The hexagonal NaGdF4:Yb3+/Ho3+/Ce3+ nano-phosphors are synthesized by a hydrothermal method. Under 980 nm excitation, the phosphor emits green, red and far-red light in the visible wavelength region, corresponding to the 5S2/5F4 → 5I8, 5F5 → 5I8 and 5S2/5F4 → 5I7 transitions of Ho3+ ions, respectively. When adjusting the Ce3+ concentration from 0% to 16%, the dominant wavelength shifts ∼43 nm toward the longer wavelength. Two cross-relaxation processes between Ho3+ and Ce3+ are responsible for the change in chromaticity. Also, the ability of the Ce3+ concentration to regulate the luminescence color depends on the pumping power and temperature of samples. More interestingly, the phosphors are potentially applicable as the optical thermometric materials. In the case of 16% Ce3+ doping, the maximum sensitivity (0.1446 K‑1) about 4–35 times as high as the reported values of several typical thermometric materials is obtained.

  20. Notas sobre as implicações psicossociais da violência na baixa prostituição feminina na cidade de Fortaleza/CE

    Directory of Open Access Journals (Sweden)

    Lorena Brito Silva

    2017-01-01

    Full Text Available http://dx.doi.org/10.5007/1807-1384.2017v14n1p176 Este artigo visa problematizar as implicações psicossociais da violência na baixa prostituição na cidade de Fortaleza/CE, buscando analisar as dinâmicas da violência e identificar suas expressões psicossociais no cotidiano das prostitutas. As violências contra prostitutas encontram-se veladas no universo da violência de gênero, reproduzindo a lógica de silenciamento que envolve a violência contra a mulher mesmo ocorrendo comumente no espaço público. A pesquisa teve uma perspectiva etnográfica, contou com a participação de 7 interlocutoras formais e utilizou a Análise de Conteúdo como referência. As análises apontam que a dinâmica da baixa prostituição é atravessada pelos arranjos territoriais, estando os códigos e regras da zona de prostituição em constante disputa com o território. A violência articula-se como uma teia relacional que acaba por impedir o reconhecimento do outro (classe, gênero ou raça/etnia mediante o uso da força física e/ou simbólica, minando as possibilidades de diálogo, por um lado, e criando outros códigos, formas de interação e performances sociais, por outro.

  1. Crystal growth of Na co-doped Ce:LiCaAlF single crystals and their optical, scintillation and physical properties

    Czech Academy of Sciences Publication Activity Database

    Yokota, Y.; Fujimoto, Y.; Yanagida, T.; Takahashi, H.; Yonetani, M.; Hayashi, K.; Park, I.; Kawaguchi, N.; Fukuda, K.; Yamaji, A.; Fukazawa, Y.; Nikl, Martin; Yoshikawa, A.

    2011-01-01

    Roč. 11, č. 11 (2011), 4775–4779 ISSN 1528-7483 Grant - others:AVČR(CZ) M100100910 Institutional research plan: CEZ:AV0Z10100521 Keywords : LiCaAlF 6 * Ce-doped * Na-codoped * fluoride * neutron scintillator * micro-pulling down method Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.720, year: 2011

  2. 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 ...

  3. The crystal structure of the new mineral dyrnaesite-(La), Na8CeIVREE2(PO4)6

    DEFF Research Database (Denmark)

    Balic Zunic, Tonci

    2017-01-01

    sites, or Na sites in a [010] row (similar to [100] in vitusite-(Ce)) assume two types of coordinations with and without mirror symmetry and two different configurations of surrounding PO4 tetrahedra. This summarizes the topological difference to vitusite-(Ce) where the corresponding coordinations...

  4. 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.

  5. Tunable white light of a Ce3+,Tb3+,Mn2+triply doped Na2Ca3Si2O8phosphor for high colour-rendering white LED applications: tunable luminescence and energy transfer.

    Science.gov (United States)

    Lü, Wei; Xu, Huawei; Huo, Jiansheng; Shao, Baiqi; Feng, Yang; Zhao, Shuang; You, Hongpeng

    2017-07-18

    A tunable white light emitting Na 2 Ca 3 Si 2 O 8 :Ce 3+ ,Tb 3+ ,Mn 2+ phosphor with a high color rendering index (CRI) has been prepared. Under UV excitation, Na 2 Ca 3 Si 2 O 8 :Ce 3+ phosphors present blue luminescence and exhibit a broad excitation ranging from 250 to 400 nm. When codoping Tb 3+ /Mn 2+ ions into Na 2 Ca 3 Si 2 O 8 , energy transfer from Ce 3+ to Tb 3+ and Ce 3+ to Mn 2+ ions is observed from the spectral overlap between Ce 3+ emission and Tb 3+ /Mn 2+ excitation spectra. The energy-transfer efficiencies and corresponding mechanisms are discussed in detail. The mechanism of energy transfer from Ce 3+ to Tb 3+ is demonstrated to be a dipole-quadrupole mechanism by the Inokuti-Hirayama model. The wavelength-tunable white light can be realized by coupling the emission bands centered at 440, 550 and 590 nm ascribed to the contribution from Ce 3+ , Tb 3+ and Mn 2+ , respectively. The commission on illumination value of color tunable emission can be tuned by controlling the content of Ce 3+ , Tb 3+ and Mn 2+ . Temperature-dependent luminescence spectra proved the good thermal stability of the as-prepared phosphor. White LEDs with CRI = 93.5 are finally fabricated using a 365 nm UV chip and the as-prepared Na 2 Ca 3 Si 2 O 8 :Ce 3+ ,Tb 3+ ,Mn 2+ phosphor. All the results suggest that Na 2 Ca 3 Si 2 O 8 :Ce 3+ ,Tb 3+ ,Mn 2+ can act as potential color-tunable and single-phase white emission phosphors for possible applications in UV based white LEDs.

  6. 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.

  7. Evaluation of the angular response of LaBr{sub 3}(Ce) and NaI(Tl) radiological identifiers for emergency situations attendance

    Energy Technology Data Exchange (ETDEWEB)

    Izidório, Ana C.A.C.; Cardoso, Domingos D’O.; Oliveira, Luciano S.R.; Balthar, Mario C.V.; Amorim, Aneuri S. de; Santos, Avelino dos; Guimarães Junior, Walter J.; Arbach, Mayara N., E-mail: carolizidorio@hotmail.com, E-mail: domingos.oliveiralvr71@gmail.com, E-mail: walter_guimaraes@ime.eb.br, E-mail: lucianosantarita@gmail.com, E-mail: mariobalthar@gmail.com, E-mail: aneurideamorim@gmail.com, E-mail: hiperav@gmail.com, E-mail: mayaraarbach@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Instituto de Defesa Química, Biológica, Radiológica e Nuclear (IDQBRN/CTEx), Barra de Guaratiba, RJ (Brazil); Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-11-01

    The Institute of Chemical, Biological, Radiological and Nuclear Defense (IDQBRN) of the Brazilian Army has been developing activities aimed at characterizing radiological detectors for use during emergency situations and radiological incidents and also for research and academic activities. This work describes the experiments performed in order to evaluate the angular response of LaBr{sub 3}(Ce) and NaI(Tl) portable radiological identifiers (PRI) with scintillator crystal detectors measuring 1.5” x 1.5” and 3.0” x 1.5”, respectively. A {sup 137}Cs source with corrected activity of 2.623 GBq (July 29, 2017) supplied the beam for the experiments. It was positioned at a distance of 1.00 m from the PRIs, together with attenuators, in order to yield different ambient dose equivalent rate, H⁎(10), thus allowing the adjustment of the counting statistics and the analysis of the responses obtained. The objective of this work was to evaluate the angular dependence of the response of LaBr{sub 3}(Ce) and NaI(Tl) PRIs exposed to a {sup 137}Cs source by azimuthally varying the angle of incidence of the primary beam within the 0° ± 30° range, measured from the center of the sensitive volume of the scintillators. The PRIs were programmed to reach a maximum count of 10{sup 6} in order to ensure that the relative uncertainty of the measured data would be negligible which led to improved angular response data, in addition to higher correlation factors and greater reliability in the responses obtained with LaBr{sub 3}(Ce) and NaI(T1) portable radiological identifiers. (author)

  8. A IMPORTÂNCIA DOS SISTEMAS DE INFORMAÇÃO NA GESTÃO DE ESCOLAS PRIVADAS NO MUNICÍPIO DE QUIXADÁ-CE

    OpenAIRE

    Tony Herbert Freitas Freire; Manoel Sandoval Fernandes Bastos Júnior

    2017-01-01

    O mundo vive em constantes mudanças tecnológicas, onde os processos de gestão a cada dia que passa, vão se desenvolvendo buscando as melhorias no atendimento e agilidade nas informações. Este trabalho tem como objetivo analisar a importância dos sistemas informatizados na gestão de escolas privadas no município de Quixadá-Ce. A presente pesquisa é do tipo descritiva, exploratória com abordagem quantitativa, e foi realizada em três escolas privadas. Os participantesda pesquisa foram gestores, ...

  9. Ultrasonic, FTIR and thermal investigations of SiO2-Na2O-CaO-P2O5 glasses doped with CeO2

    Science.gov (United States)

    Marzouk, Samir Y.

    2010-11-01

    The longitudinal and shear ultrasonic wave velocities for different compositions of SiO2-Na2O-CaO-P2O5 glasses were measured at room temperature (305 K) using a pulse-echo method at a frequency of 4 MHz. The elastic moduli, Poisson's ratio, microhardness, Debye temperature and other ultrasonic parameters were obtained from experimental data and analyzed using bond compression theory. By calculating the number of network bonds per unit volume, the average stretching constant, and the average ring size, information about the structure of the glass can be deduced. Structural changes after doping with CeO2 were investigated by FTIR spectroscopy, and by measurements of the thermal expansion coefficient, glass transition and softening temperature to throw more light on the characterization of these glasses.

  10. Modelagem do fluxo de contaminantes em aquífero freático na área do cemitério Bom Jardim, Fortaleza, CE, Brasil

    OpenAIRE

    Sousa, Mauro César de Brito; Castro, Marco Aurélio Holanda de; Castro, David Lopes de; Alencar Neto, Mariano da Franca; Lopes, Bruno Leonardy Sousa

    2012-01-01

    A contaminação de aquíferos freáticos pela decomposição de corpos em cemitérios configura-se como uma realidade comum no Brasil e no mundo. Na cidade de Fortaleza (CE), o cemitério Bom Jardim é um típico exemplo da ameaça de contaminação. O risco se deve, principalmente, pelo fato de que frequentemente a população utiliza-se das águas do aquífero freático para os mais diversos fins. Nesta investigação, analisou-se a possibilidade do cemitério Bom Jardim contribuir para a contaminação microbio...

  11. Comparison of experimental results of a Quad-CZT array detector, a NaI(Tl), a LaBr3(Ce), and a HPGe for safeguards applications

    Science.gov (United States)

    Kwak, S.-W.; Choi, J.; Park, S. S.; Ahn, S. H.; Park, J. S.; Chung, H.

    2017-11-01

    A compound semiconductor detector, CdTe (or CdZnTe), has been used in various areas including nuclear safeguards applications. To address its critical drawback, low detection efficiency, which leads to a long measurement time, a Quad-CZT array-based gamma-ray spectrometer in our previous study has been developed by combining four individual CZT detectors. We have re-designed the developed Quad-CZT array system to make it more simple and compact for a hand-held gamma-ray detector. The objective of this paper aims to compare the improved Quad-CZT array system with the traditional gamma-ray spectrometers (NaI(Tl), LaBr3(Ce), HPGe); these detectors currently have been the most commonly used for verification of nuclear materials. Nuclear materials in different physical forms in a nuclear facility of Korea were measured by the Quad-CZT array system and the existing gamma-ray detectors. For measurements of UO2 pellets and powders, and fresh fuel rods, the Quad-CZT array system turned out to be superior to the NaI(Tl) and LaBr3(Ce). For measurements of UF6 cylinders with a thick wall, the Quad-CZT array system and HPGe gave similar accuracy under the same measurement time. From the results of the field tests conducted, we can conclude that the improved Quad-CZT array system would be used as an alternative to HPGes and scintillation detectors for the purpose of increasing effectivenss and efficiency of safeguards applications. This is the first paper employing a multi-element CZT array detector for measurement of nuclear materials—particularly uranium in a UF6 cylinder—in a real nuclear facility. The present work also suggests that the multi-CZT array system described in this study would be one promising method to address a serious weakness of CZT-based radiation detection.

  12. Resistividade do filme depositado via sol-gel e estado de oxidação do dopante Ce na matriz SnO2 Resistivity of the film deposited via sol-gel and oxidation state of Ce doping in SnO2 matrix

    Directory of Open Access Journals (Sweden)

    L. V. A. Scalvi

    2011-06-01

    Full Text Available Incorporação de Ce3+ ou Ce4+ em filmes finos de SnO2 depositados via sol-gel-dip-coating aumenta drasticamente a resistividade elétrica. No primeiro caso, temos comportamento aceitador do dopante, levando a matriz à alta compensação de carga. Por outro lado, para Ce4+, verifica-se aumento na largura da região de depleção do contorno de grão, resultando em maior espalhamento de elétrons. Medidas de caracterização elétrica sob pressão ambiente levam à barreiras de potencial mais altas do que as medidas sob vácuo, devido a adsorção de oxigênio na superfície das partículas. A presença de Ce3+ aumenta a transmitância no infravermelho, o que significa menor quantidade de elétrons livres. Dados de XANES confirmam que o tratamento térmico a 550 ºC dos filmes, ainda que promova oxidação parcial para Ce4+, preserva uma quantidade significativa (em torno de 60% no estado Ce3+. Espectroscopia Raman mostra a evolução dos modos de vibração intra-grãos de SnO2 com o aumento da temperatura de tratamento térmico.Incorporation of Ce3+ or Ce4+ in sol-gel dip-coating SnO2 thin films increases drastically its electrical resistivity. In the first case, it is due the acceptor-like nature of the doping ion, leading the matrix to high charge compensation. On the other hand, for Ce+4 doped samples, it is verified a broadening of the grain boundary depletion layer. Measurements under room pressure leads to higher intergrain potential barriers when compared to measurements carried out under vacuum conditions, due to oxygen adsorption at particles surface. The presence of Ce3+ increases the infrared transmittance, which means a lower free electron concentration. XANES data confirms that the thermal annealing at 550 ºC of thin films, although promotes oxidation to Ce4+, still keeps a significantly amount (about 60% of ions in the oxidation state Ce3+. Raman spectroscopy data show the evolution of the SnO2 bulk vibration modes with

  13. 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

  14. 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.

  15. 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.

  16. Inserção dos atores sociais locais na gestão do turismo em Jericoacoara - CE

    Directory of Open Access Journals (Sweden)

    José Osmar Fonteles

    2015-01-01

    Full Text Available As áreas protegidas têm se constituído em espaços privilegiados para o turismo, despertando o interesse do poder público e da iniciativa privada, com investimentos no setor. Recursos ambientais são identificados e transformados em produtos, com marketing especializado montando e/ou projetando cenários que atendem aos interesses dos visitantes. Assim, lugares até então inexplorados turisticamente, passam a ser visitados por pessoas oriundas de culturas distintas, alterando o jeito de ser dos moradores locais, sobretudo quando são impactados pela presença e convivência de outros moradores que ocupam o seu território. Este é o contexto em que desenvolvemos o presente trabalho tendo por objetivo analisar o turismo no segmento Sol e Praia, no sentido de compreender como se dá a inserção dos atores sociais locais na construção e comercialização de produtos que atendam aos interesses dos visitantes, gerando renda e inclusão socioambiental, a partir de uma gestão integrada. O texto faz referência à Jericoacoara antes e com a entrada do turismo, ressaltando a ação dos moradores nativos e adventícios na produção do espaço geográfico e sociocultural para o turismo, com destaque para o segmento Sol e Praia. Enfatizo a forma de como os diversos atores sociais se organizam para se fortalecerem enquanto Destino Indutor do Turismo, a partir das suas categorias sociais e ocupacionais e da gestão institucional materializada no órgão municipal do turismo, no conselho municipal do turismo, no grupo gestor e na instância de governança regional. Relato a experiência do ordenamento do trânsito em Jericoacoara, ação demandada pela comunidade, apoiada pelo governo estadual e municipal.   Palavras chaves: turismo, segmento sol e praia, destino indutor, gestão

  17. Luminescence properties of a single-component Na0.34Ca0.66Al1.66Si2.34O8:Ce3+, Sm3+ phosphor with tunable color tone for UV-pumped LEDs

    Science.gov (United States)

    Wang, Lei; Dong, Jie; Cui, Cai'e.; Tian, Yue; Huang, Ping

    2015-08-01

    A series of single-phase Na0.34Ca0.66Al1.66Si2.34O8:Ce3+, Sm3+ (NCASO) phosphors have been synthesized via a high temperature solid-state reaction method. The samples were studied based on photoluminescence (PL), photoluminescence excitation (PLE) spectra and fluorescence decay patterns. The obtained PLE exhibited a strong excitation band in the UV region between 250 and 380 nm. Under 340 nm excitation, NCASO:Ce3+, Sm3+ phosphor showed a broad emission band at 414 nm of Ce3+ and four emission bands from 550 nm to 725 nm of Sm3+. Spectra demonstrate nonradiative energy transfers (ET) occur from Ce3+-Sm3+. The analysis based on Inokuti-Hirayama model indicates that the ET is governed by electric dipole-dipole interaction. Moreover, the emitting colors can be adjusting from blue to white by proper tuning of the relative composition of Ce3+/Sm3+. These results show that NCASO:Ce3+, Sm3+ phosphors can be used as a potential single-phased white-emitting candidate for UV WLEDs.

  18. 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

  19. A IMPORTÂNCIA DOS SISTEMAS DE INFORMAÇÃO NA GESTÃO DE ESCOLAS PRIVADAS NO MUNICÍPIO DE QUIXADÁ-CE

    Directory of Open Access Journals (Sweden)

    Tony Herbert Freitas Freire

    2017-06-01

    Full Text Available O mundo vive em constantes mudanças tecnológicas, onde os processos de gestão a cada dia que passa, vão se desenvolvendo buscando as melhorias no atendimento e agilidade nas informações. Este trabalho tem como objetivo analisar a importância dos sistemas informatizados na gestão de escolas privadas no município de Quixadá-Ce. A presente pesquisa é do tipo descritiva, exploratória com abordagem quantitativa, e foi realizada em três escolas privadas. Os participantesda pesquisa foram gestores, funcionários e colaboradores responsáveis pela administração geral e financeira de cada setor dentro da escola entrevistada. Ao serem questionados, verificou-se que 44,4% dos entrevistados consideram que com os sistemas é possível ter mais organização, eficiência e praticidade nas informações, 44,4% disseram que é de fundamental importância a agilidade imposta ao trabalho a partir dos dados fornecidos pelo sistema e outros 11,1% relataram sobre o enriquecimento de informações extraídas através de relatórios ou gráficos. Sobre as mudanças alcançadas com o processo de implantação do sistema, foi visto que a mudança ajudou significativamente no desenvolvimento da instituição. Conclui-se, portanto que os sistemas informatizados ajudaram bastante no desenvolvimento das escolas pesquisadas, e os próprios usuários relatam que usam o sistema como uma ferramenta na de tomada de decisões.

  20. Preparation of Na4UO2(CO3)3 in presence of Ce-141. I, Influence of the post-reaction time in the concentration of anion species of Ce-141

    International Nuclear Information System (INIS)

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

    1991-10-01

    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)

  1. Bioactivity of Y2O3 and CeO2 doped SiO2-SrO-Na2O glass-ceramics.

    Science.gov (United States)

    Placek, L M; Keenan, T J; Wren, A W

    2016-08-01

    The bioactivity of yttrium and cerium are investigated when substituted for Sodium (Na) in a 0.52SiO2-0.24SrO-0.24-xNa2O-xMO glass-ceramics (where x = 0.08 and MO = Y2O3 or CeO2). Bioactivity is monitored through pH and inductively coupled plasma-optical emission spectrometry where pH of simulated body fluid ranged from 7.5 to 7.6 and increased between 8.2 and 10.0 after 14-day incubation with the glass-ceramic disks. Calcium (Ca) and phosphorus (P) levels in simulated body fluid after incubation with yttrium and cerium containing disks show a continual decline over the 14-day period. In contrast, Con disks (not containing yttrium or cerium) caused the elimination of Ca in solution after 1 day and throughout the incubation period, and initially showed a decline in P levels followed by an increase at 14 days. Scanning electron microscopy and energy dispersive spectroscopy confirmed the presence of Ca and P on the surface of the simulated body fluid-incubated disks and showed precipitates on Con and HCe (8 mol% cerium) samples. Cell viability of MC3T3 osteoblasts was not significantly affected at a 9% extract concentration. Optical microscopy after 24 h cell incubation with disks showed that Con samples do not support osteoblast or Schwann cell growth, while all yttrium and cerium containing disks have direct contact with osteoblasts spread across the wells. Schwann cells attached in all wells, but only showed spreading with the HY-S (8 mol% yttrium, heated to sintering temperature) and YCe (4 mol% yttrium and cerium) disks. Scanning electron microscopy of the compatible disks shows osteoblast and sNF96.2 Schwann cells attachment and spreading directly on the disk surfaces. © The Author(s) 2016.

  2. 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)

  3. Piezoelectric properties enhanced of Sr0.6(BiNa)0.2Bi2Nb2O9 ceramic by (LiCe) modification with charge neutrality

    International Nuclear Information System (INIS)

    Fang, Pinyang; Xi, Zengzhe; Long, Wei; Li, Xiaojuan; Li, Jin

    2013-01-01

    Graphical abstract: The oxygen vacancies were confirmed by the left figure. The role of oxygen vacancy on piezoelectric activities was obtained by comparing to the varieties of oxygen vacancy concentration and piezoelectric coefficient with (LiCe) modification. -- Highlights: • The Sr 0.6 (BiNa) 0.2 Bi 2 Nb 2 O 9 ceramic by (LiCe) modification with the charge neutrality was synthesized by the solid state reaction method. • The Curie temperature and piezoelectric coefficient were found to be T c ∼590 °C and d 33 ∼32 pC/N, respectively. • The mechanism of piezoelectric activities improved by (LiCe) modification was discussed. -- Abstract: Aurivillius-type ceramics, Sr 0.6−x (LiCe) x/2.5 (BiNa) 0.2 Bi 2 Nb 2 O 9 (SLCBNBNO) with the charge neutrality, were synthesized by using conventional solid-state processing. Phase analysis was performed by X-ray diffraction analyses (XRD) and Raman spectroscopy. Microstructural morphology was assessed by the scanning electron microscopy (SEM). Structural, dielectric, piezoelectric, ferroelectric, and electromechanical properties of the SLCBNBNO ceramics were investigated. Piezoelectric properties were significantly enhanced compared to Sr 0.6 (BiNa) 0.2 Bi 2 Nb 2 O 9 (SBNBN) ceramic and the maximum of piezoelectric coefficient d 33 of the SBNBN-LC6 ceramic was 32 pC/N with higher Curie temperature (T c ∼590 °C). In addition, mechanisms for the piezoelectric properties enhanced of the SBNBN-based ceramics were discussed

  4. 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

  5. Espaço Público e Shopping Center na Cidade Contemporânea: Novos Significados do North Shopping em Fortaleza - CE

    Directory of Open Access Journals (Sweden)

    Tiago Estevam Gonçalves

    2012-03-01

    Full Text Available Iniciar uma reflexão acerca da cidade atual nos remete à necessidade de construirmos uma análise sobre os shopping centers como espaços que tem atraído um fluxo considerável da população, ocasionando mudanças na relação dos citadinos com os espaços públicos. Nesta perspectiva, temos como objetivo analisar o North Shopping, localizado na cidade de Fortaleza, como um espaço de uso popular onde as camadas de menor poder aquisitivo podem adentrar e usufruir de seus atributos. Imbuídos de tal finalidade nosso aporte teórico fundamentou-se em Pintaudi (1992, Dantas (1995, Silva (1996 Lefebvre (1999, Carlos (2001, Gomes (2002 e Serpa (2007. Conclui-se que na cidade de Fortaleza, o North Shopping é um verdadeiro simulacro da realidade, substituindo as experiências cotidianas dos espaços públicos, configurando-se, assim, a supervalorização do espaço privado que se traveste de público tendo repercussões na nova urbanidade fortalezense.

  6. 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

  7. 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)

  8. PRODUÇÃO DO ESPAÇO URBANO: NORTH SHOPPING NA DINÂMICA DE NOVAS CENTRALIDADES EM FORTALEZA- CE

    Directory of Open Access Journals (Sweden)

    Tiago Estevam Gonçalves

    2011-04-01

    Full Text Available Esta pesquisa tem como objetivo analisar a formação das novas centralidades em Fortaleza e sua relação com os shopping centers, tendo como shopping em destaque: North Shopping (inaugurado em 1991, localizado na avenida Bezerra de Menezes . No campo metodológico, realizaram-se levantamentos bibliográficos sobre a formação novas centralidades, o processo de produção do espaço urbano fortalezense incentivado pelo setor terciário e shopping center que contribuíram para o entendimento da transformação da cidade, além disso, realizamos visitamos e entrevistas no Norh Shopping. Uma das primeiras áreas centrais a se desenvolver além do Centro tradicional foi a da Aldeota incentivada pelo Center Um (instalado em 1974, na avenida Santos Dumont. Desde a formação das primeiras novas centralidades até o período atual sempre existiu uma relação intrínseca entre estas com os shoppings. Estes equipamentos modernos (shoppings aparecem com novos espaços de consumo ou novos consumos de espaço que cria e recria novas formas para atrair as pessoas ao consumo, considerando o consumir como signo de felicidade. Nesta perspectiva podemos afirmar que as atividades terciárias e os equipamentos modernos de consumo atuam no crescimento e na organização do espaço urbano, assim geram uma dinâmica comercial em Fortaleza.

  9. Caracterização pós-colheita de figos (Ficus carica L. produzidos sob diferentes condições de cultivo na Chapada do Apodi – CE.

    Directory of Open Access Journals (Sweden)

    Raniely Nayanne da Silva Freitas

    2015-03-01

    Full Text Available A produção de figos para consumo in natura é limitada pelas chuvas, que causam elevadas perdas por podridão, o que pode dificultar o seu cultivo durante a estação chuvosa local (fevereiro a maio, época em que a fruta atinge a sua maior cotação. Essa dificuldade poderá ser contornada com o uso de ambiente protegido. Objetivou-se com o presente trabalho, realizar a caracterização da qualidade pós-colheita de figos produzidos sob cultivo protegido e a céu aberto na Chapada do Apodi- CE. Os frutos utilizados neste experimento foram colhidos em pomar experimental da Unidade de Ensino e Pesquisa (UEPE, pertencente ao Instituto Federal de Educação, Ciência e Tecnologia do Ceará (IFCE, localizada na Chapada do Apodi em Limoeiro do Norte – Ceará, onde os mesmos foram cultivados a céu aberto e em estufa.  Foram realizadas as seguintes análises: diâmetro do fruto, peso do fruto, firmeza da polpa, sólidos solúveis (SS, acidez titulável(AT, pH, RATIO e vitamina C. De acordo com os parâmetros analisados, os figos cultivados em estufa apresentaram melhores atributos físico-químicos em relação aos cultivados em céu aberto, concluindo-se que, o tipo de cultivo influencia na qualidade pós-colheita do fruto.

  10. Saga Cigana: narrativas (auto biográficas intergeracionais na comunidade do bairro Sumaré no município de Sobral-CE

    Directory of Open Access Journals (Sweden)

    Liana Liberato Lopes Carlos

    2017-11-01

    Full Text Available Quem são, como vivem, o que pensam os integrantes de várias gerações ciganas? O que sabemos sobre eles são transmitidos por eles mesmos ou pelo filtro do preconceito, da discriminação e do estigma? Em que medida o diálogo intercultural permeia a visão que a sociedade tem da comunidade cigana? Este artigo descreve e analisa três narrativas autobiográficas intergeracionais ciganas compostas por uma família organizada em pai, filha e tio, que serão denominados de: SOL, LUA e ESTRELA, respectivamente. A comunidade cigana em estudo está situada no Bairro Sumaré, no município de Sobral, no Ceará. As narrativas orais foram coletadas em forma de entrevistas semiestruturadas. O principal resultado da pesquisa nos revela que a comunidade cigana ainda vive envolta no preconceito, na estigmatização. Percebemos, na pesquisa que, a comunidade faz sua história para enfrentar as situações de estigma e exclusão sócio-cultural, com atitudes de resistências, mantendo seus costumes e jeito de ser. Por fim, compreendemos que ouvir a comunidade cigana, suas vozes, para servirmos como amplificadores de suas resistências, possibilita manter e recuperar suas identidades culturais, no que diz respeito às suas origens.

  11. 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

  12. O setor hoteleiro na praia de Canoa Quebrada/CE: processo de expansão urbana e turística

    Directory of Open Access Journals (Sweden)

    Felipe de Souza Siqueira

    2017-06-01

    Full Text Available Este artigo discute a expansão da atividade turística na praia de Canoa Quebrada - Ceará, buscando entender suas implicações sobre o desenvolvimento do setor hoteleiro a partir das iniciativas pioneiras na década de 1970 até sua ampliação nos dias atuais. Seu foco principal é o setor hoteleiro, sua expansão e as transformações decorrentes do crescimento urbano e dos fluxos turísticos, abarcando as origens e as principais características desse setor, bem como a sua relação com a evolução da localidade. A operacionalização da pesquisa impôs a definição de um referencial teórico apropriado ao entendimento do processo de expansão da cidade e dos fluxos turísticos, de modo a propiciar a apreensão da totalidade dos elementos naturais e humanos definidores da realidade investigada. A análise dos processos locais relativos à expansão urbana e turística exigiu a sua articulação ao contexto regional e nacional, bem como a consulta à obras capazes de oferecer elementos acerca da realidade objeto da investigação, elucidando aspectos relacionados às origens e a evolução do setor hoteleiro, decorrentes de transformações sócio espaciais ocorridas em Canoa Quebrada.

  13. Processing temperature tuned interfacial microstructure and protonic and oxide ionic conductivities of well-sintered Sm0.2Ce0.8O1.9- Na2CO3 nanocomposite electrolytes for intermediate temperature solid oxide fuel cells

    Science.gov (United States)

    Li, Chuanming; Zeng, Yanwei; Wang, Zhentao; Ye, Zhupeng; Zhang, Yuan

    2017-08-01

    Well-sintered SDC-NC (Sm0.2Ce0.8O1.9-Na2CO3) nanocomposites have been prepared through a rare-earth/sodium complex carbonate precipitation, powder prefirings at the temperatures 400, 500 and 600 °C and sintering at 800 °C. Their sintering performances, phase components and microstructures have been characterized by Archimedean method, XRD and FESEM techniques. In particular, the influence of the interfacial interactions between the phases of SDC and NC on the microstructures and electrical conductivities of SDC-NC nanocomposites have been investigated by AC impedance and Raman spectroscopies. It has been found that on the basis of the fitting analysis of AC impedance data, the oxide ionic and protonic conductivities of interfacial and non-interfacial phases in the SDC-NC nanocomposites are found to be strongly dependent upon their prefiring temperatures with the sample of SN-600 showing the highest values of 73.2/33.7 and 51.1/105.4 μS/cm at 300 °C, respectively. The single cell based on the electrolyte of SN-600 presents an OCV of 0.992 V and peak power density of 421 mW/cm2 at 550 °C. The interfacial interactions between the phases of SDC and NC inside SDC-NC nanocomposites are considered responsible for their differences in microstructure and electrical conductivity.

  14. 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

    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.

  15. 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.

  16. 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.

  17. Synthesis and characterization of CeO{sub 2} - TiO{sub 2} system for use in heterogeneous photocatalysis in photodegradation of methylene blue dye; Sintese e caracterizacao do sistema CeO{sub 2} - TiO{sub 2} para aplicacao em fotocatalise heterogenea na fotodegradacao do corante azul de metileno

    Energy Technology Data Exchange (ETDEWEB)

    Bragatto, Julia

    2016-07-01

    This study has as its goal the synthesis of a mixed oxide system type CeO{sub 2} - TiO{sub 2}, through the polymeric precursor method, to be used in heterogeneous photocatalysis. The synthesized materials were characterized by Thermogravimetry (TG), Derivative Thermogravimetry (DTG), Differential Thermal Analysis (DTA) and X-Ray Diffraction (XRD). The results of the thermal analysis showed in what temperature ranges certain events occur such as the formation of cerium oxide between 600 and 800 ° C, which refers to the crystallization of the material. Regarding the formation of titanium oxide, events between 600 and 800 ° C are perceived, which suggests the transformation of anatase to rutile phase. The XRD analysis showed no occurrence of the same phase for all materials, meaning that there is a variation in the formation of phases according to concentration of precursor for each sample. Noteworthy are the formation of CeO{sub 2} for Ce75-Ti25 and Ce50-Ti50 concentrations, with cubic crystal structure of the fluorite type. In Ce75-Ti25 and Ce25-Ti75 it is present the TiO{sub 2} in the anatase and rutile phase, with crystal structure of the tetragonal and tetrahedron type, respectively, as well as the formation of CeTi{sub 2}O{sub 6} in Ce50-Ti50 and Ce25-Ti75, with structure monoclinic. From these analyses, it is possible to see which samples, and in which temperatures of calcination the material has increased crystallinity, making the choice for their application in heterogeneous photocatalysis, aiming the degradation of methylene blue dye. Among the tested materials for methylene blue, the sample that stood out was the Ce50-Ti50, with calcination temperature of 800 °C, with values close to 50% degradation, because it was the sample that showed higher dye adsorption capacity, which is the step that precedes photodegradation. (author)

  18. Uso da aspiração manual a vácuo na redução do custo e duração de internamentos por aborto incompleto em Fortaleza, CE, Brasil

    Directory of Open Access Journals (Sweden)

    Fonseca Walter

    1997-01-01

    Full Text Available INTRODUÇÃO: O uso de aspiração a vácuo (AV no tratamento do aborto incompleto é prática bastante difundida em países desenvolvidos. Vários estudos nesses países indicam que o uso da técnica de aspiração manual a vácuo (AMV pode conservar recursos do sistema de saúde e melhorar a qualidade do tratamento do aborto. No Brasil, o uso da AMV é procedimento de rotina nos hospitais e clínicas privados. Entretanto, na maioria dos hospitais da rede pública é utilizada somente a técnica de dilatação e curetagem (D&C. METODOLOGIA: Foram utilizados métodos de avaliação rápida para estimar a variação do custo médio do tratamento e duração da estadia hospitalar, em um grupo de 30 pacientes admitidas com aborto incompleto em hospital público de Fortaleza, CE (Brasil. Participantes foram alocadas, randomicamente, em um dos dois grupos de tratamento investigados (AMV ou D&C. RESULTADOS E CONCLUSÕES: Os resultados sugerem que o uso da AMV, em substituição a D&C, no tratamento do aborto incompleto, pode reduzir em até 41% o custo médio do tratamento e em 77% o tempo médio de hospitalização. Recomenda-se a realização de estudos confirmatórios, como também que se aprofunde os conhecimentos sobre a percepção do aborto e seu tratamento por parte do pessoal de saúde e da população feminina.

  19. Uso da aspiração manual a vácuo na redução do custo e duração de internamentos por aborto incompleto em Fortaleza, CE, Brasil

    Directory of Open Access Journals (Sweden)

    Walter Fonseca

    1997-10-01

    Full Text Available INTRODUÇÃO: O uso de aspiração a vácuo (AV no tratamento do aborto incompleto é prática bastante difundida em países desenvolvidos. Vários estudos nesses países indicam que o uso da técnica de aspiração manual a vácuo (AMV pode conservar recursos do sistema de saúde e melhorar a qualidade do tratamento do aborto. No Brasil, o uso da AMV é procedimento de rotina nos hospitais e clínicas privados. Entretanto, na maioria dos hospitais da rede pública é utilizada somente a técnica de dilatação e curetagem (D&C. METODOLOGIA: Foram utilizados métodos de avaliação rápida para estimar a variação do custo médio do tratamento e duração da estadia hospitalar, em um grupo de 30 pacientes admitidas com aborto incompleto em hospital público de Fortaleza, CE (Brasil. Participantes foram alocadas, randomicamente, em um dos dois grupos de tratamento investigados (AMV ou D&C. RESULTADOS E CONCLUSÕES: Os resultados sugerem que o uso da AMV, em substituição a D&C, no tratamento do aborto incompleto, pode reduzir em até 41% o custo médio do tratamento e em 77% o tempo médio de hospitalização. Recomenda-se a realização de estudos confirmatórios, como também que se aprofunde os conhecimentos sobre a percepção do aborto e seu tratamento por parte do pessoal de saúde e da população feminina.

  20. INFLUÊNCIAS E SIGNIFICADOS DA FESTA DE SÃO FRANCISCO DAS CHAGAS NO COMÉRCIO VAREJISTA E NA COTIDIANIDADE DA POPULAÇÃO DE CANINDÉ-CE

    Directory of Open Access Journals (Sweden)

    Francisco John Lennon Alves Paixão Lima

    2017-03-01

    Full Text Available O presente artigo analisa as influências e os significados da festa de São Francisco das Chagas no comércio varejista e na vida dos moradores da cidade de Canindé-CE. Para tal, foi aplicado questionário com a população e realizado entrevista com representantes da Basílica de São Francisco das Chagas e da Prefeitura Municipal. Foi também realizado trabalho de campo em 2014 (no período das festividades do padroeiro e em março de 2015. Realizou-se ainda pesquisa bibliográfica em livros, jornais e sites específicos, como IBGE e IPECE. A crença no santo promove um movimento periódico de romeiros à Canindé e se caracteriza enquanto movimento cosmogônico. Os resultados apontam uma interdependência sacro-profana vivenciada pela população da cidade, que vê a festa do padroeiro como uma forma de geração de renda, de satisfação espiritual e identidade cultural: devoção no santo, aquecimento da economia local e pertencimento. Apesar da importância religiosa e econômica da festa, ainda é pouco o que resulta para a cidade: há necessidade de maior investimento em infraestrutura dedica ao romeiro, bem como à satisfação de sua população. Apesar disso, a infraestrutura dedicada à comercialização de produtos que expressam a religiosidade no padroeiro, assim como aquela aos romeiros, apresenta notório crescimento.

  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. Założenia rekreacji terapeutycznej i jej rola na podstawie badań przeprowadzonych w wakacyjnym ośrodku rekreacyjnym Barretstown dla dzieci cierpiących na choroby przewlekłe i zagrażające życiu

    Directory of Open Access Journals (Sweden)

    Joanna Kondracka

    2013-03-01

    Full Text Available Wraz z postępem medycyny maleje liczba dzieci umierających na poważne choroby somatyczne, takie jak nowotwory, białaczka, choroby układu odpornościowego. Jednocześnie wzrasta liczba dzieci, które latami żyją z poważną, prze‑ wlekłą chorobą i na co dzień borykają się ze skutkami ubocznymi długoterminowego leczenia, niemożnością uczest‑ nictwa w normalnych aktywnościach swych rówieśników, ze swoją odmiennością i stałym poczuciem zagrożenia. Do takich właśnie dzieci adresowane są organizowane w USA i w krajach Europy Zachodniej obozy terapeutyczne. Barretstown w Irlandii jest jednym z tego typu ośrodków, gdzie pomaga się dzieciom przy użyciu rekreacji terapeu‑ tycznej (therapeutic recreation, TR. Jest to metoda oparta na procesie przemiany, możliwej, gdy dziecko poczuje się wyjątkowe i niepowtarzalne, bezpieczne i szczęśliwe. U podłoża teoretycznego TR leży wiara w zdolność jednostki do wzbogacenia i zdefiniowania siebie na nowo w oparciu o cztery etapy towarzyszące działaniom: wyzwanie, suk‑ ces, refleksja, odkrycie. Według profesora Petera Kearneya, pediatry z Uniwersytetu w Cork w Irlandii, przemiana, jakiej mogą doświadczać uczestnicy obozów w Barretstown, przypomina proces przejścia znany w literaturze tema‑ tu jako rite of passage. W Barretstown przeprowadzonych zostało kilka badań mających na celu ustalenie skuteczno‑ ści i wpływu TR na poprawę stanu dzieci. Ich rezultaty przedstawia poniższe opracowanie. Istnieje wyraźna potrze‑ ba kontynuacji badań oraz studiów poszczególnych przypadków. Jednocześnie dotychczasowe wyniki i obserwacje psychologów potwierdzają istotną rolę TR we wspieraniu oraz leczeniu dzieci dotkniętych przez poważne chronicz‑ ne choroby somatyczne oraz ich rodzin.

  3. Effect of cerium on the corrosion behaviour of sintered (Nd,Ce)FeB magnet

    Science.gov (United States)

    Yang, Lijing; Bi, Mengxue; Jiang, Jianjun; Ding, Xuefeng; Zhu, Minggang; Li, Wei; Lv, Zhongshan; Song, Zhenlun

    2017-06-01

    For the balanced consumption of rare-earth elements, cerium (Ce) was partially used for NdFeB magnets instead of Nd. The corrosion behaviour of the (Nd,Ce)FeB magnet with different Ce contents in 3.5% NaCl solution was investigated by SEM, XRD, EDS and electrochemical tests. After immersion, the weight loss was calculated and the magnetic properties of the samples were measured. Results showed that Ce affected the corrosion of the (Nd,Ce)FeB magnet. Compared with the NdFeB magnet without Ce but of the same grade as the magnetic energy product, (Nd,Ce)FeB magnet showed better corrosion resistance. With increased Ce content, the corrosion resistances and magnetic properties of (Nd,Ce)FeB magnets were investigated.

  4. Desenvolvimento de métodos rápidos para determinação de Codeína, Diclofenaco e seus contra-íons por eletroforese capilar com detecção condutométrica sem contato (CE-C4D)

    OpenAIRE

    Cunha, Rafael Rodrigues

    2013-01-01

    Neste trabalho são apresentados novos procedimentos analíticos para determinação rápida (t < 1 min) de codeína (COD), diclofenaco (DCF) e seus contraíons sódio (Na), potássio (K), dietilamônio (DEA) e fosfato via eletroforese capilar com detecção condutométrica sem contato acoplada capacitivamente (CE-C4D). Os métodos propostos podem ser usados no controle de qualidade de matérias primas e de formulações farmacêuticas que possuam tais compostos em sua composição. Dois método...

  5. 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)

  6. Diode-pumped Er3+:Yb3+:NaCe0.43Gd0.57(WO4)2 pulse laser passively Q -switched with a Co2+:Mg0.4Al2.4O4 saturable absorber at 1.53 μ m

    International Nuclear Information System (INIS)

    Chen, Y J; Huang, J H; Lin, Y F; Luo, Z D; Huang, Y D; Zou, Y Q

    2014-01-01

    Based on the long fluorescence lifetime of upper laser level 4 I 13/2 of Er 3+ ions and high 1.5−1.6 μm laser operation efficiency, an Er 3+ :Y b 3+ :NaCe 0.43 Gd 0.57 (WO 4 ) 2 crystal was used to generate a Q-switched pulse laser with high energy and low threshold. End-pumped by a 970 nm diode laser, a passively Q-switched 1.5−1.6 μm pulse laser was first realized in an Er 3+ and Y b 3+ co-doped tungstate crystal, when a Co 2+ :Mg 0.4 Al 2.4 O 4 spinel crystal was used as saturable absorber. A 1.53 μm pulse laser with about 22 μJ energy, 76 ns duration and 21 kHz repetition rate was obtained at an absorbed pump power of 12 W in a c-cut 1.7-mm-thick Er 3+ :Y b 3+ :NaCe 0.43 Gd 0.57 (WO 4 ) 2 crystal. (paper)

  7. 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...... a first-order phase transition at TN. At approximately TN/2 there is a first-order phase transition to a FCC type IA low-temperature configuration. The unusual magnetic properties of CeSb, which result from anisotropic exchange and crystalline electric field effects, resemble those of certain actinide Na...

  8. Preparation and screening of various multi-component catalysts for NOx conversion under lean-burn conditions : An active and heat-resistant RhPt-NaMn-Ce/Al2O3 catalyst

    OpenAIRE

    Kaneeda, M.; Iizuka, H.; Hiratsuka, T.; Shinotsuka, N.; Kitahara, Y.; Arai, M.

    2010-01-01

    The present work has been undertaken to improve the thermal stability of an RhPt-NaTi/Al2O3 catalyst, which is one of promising lean NOx trap catalysts for practical NOx conversion. For this purpose, we mainly directed our attention to the component of Na that acts as NOx trapping sites and intended to improve the thermal stability of this Na species by using various additives. After screening of various RhPt-Naα/Al2O3 (α = Ti, Si, Mg, Ca, Mn, Co, Ni, La, and Nd) catalysts, Mn addition was fo...

  9. Mianningite, (□,Pb,Ce,Na) (U{sup 4+},Mn,U{sup 6+}) Fe{sup 3+}{sub 2}(Ti,Fe{sup 3+}){sub 18}O{sub 38}, a new member of the crichtonite group from Maoniuping REE deposit, Mianning county, southwest Sichuan, China

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Xiangkun; Fan, Guang; Chen, Zhangru; Ai, Yujie [Beijing Research Institute of Uranium Geology, Beijing (China); Li, Guowu [China Univ. of Geosciences, Beijing (China). Lab. of Crystal Structure; Shen, Ganfu [Chengdu Institute of Geology and Mineral Resources, Chengdu (China)

    2017-05-15

    Mianningite (IMA 2014-072), ideally (□,Pb,Ce,Na)(U{sup 4+},Mn,U{sup 6+}) Fe{sup 3+}{sub 2}(Ti,Fe{sup 3+}){sub 18}O{sub 38}, is a new member of the crichtonite group from the Maoniuping REE deposit, Mianning county, Sichuan province, China. It was found in fractures of lamprophyre veins and in the contact between lamprophyre and a later quartz-alkali feldspar syenite dyke with REE mineralization, and is named after its type locality. Associated minerals are microcline, albite, quartz, iron-rich phlogopite, augite, muscovite, calcite, baryte, fluorite, epidote, pyrite, magnetite, hematite, galena, hydroxylapatite, titanite, ilmenite, rutile, garnet-group minerals, zircon, allanite-(Ce), monazite-(Ce), bastnaesite-(Ce), parisite-(Ce), maoniupingite-(Ce), thorite, pyrochlore-group minerals and chlorite. Mianningite occurs as opaque subhedral to euhedral tabular crystals, up to 1-2 mm in size, black in color and streak, and with a submetallic luster. Mianningite is brittle, with a conchoidal fracture. Its average micro-indentation hardness is 83.8 kg/mm{sup 2} (load 0.2 kg), which is equivalent to ∝6 on the Mohs hardness scale. Its measured and calculated densities are 4.62 (8) g/cm{sup 3} and 4.77 g/cm{sup 3}, respectively. Under reflected light, mianningite is grayish white, with no internal reflections. It appears isotropic and exhibits neither bireflectance nor pleochroism. The empirical formula, calculated on the basis of 38 O atoms per formula unit (apfu), is [□{sub 0.322}(Pb{sub 0.215}Ba{sub 0.037}Sr{sub 0.036}Ca{sub 0.010}){sub Σ0.298}(Ce{sub 0.128}La{sub 0.077}Nd{sub 0.012}){sub Σ0.217} (Na{sub 0.127}K{sub 0.036}){sub Σ0.163}]{sub Σ01.000}(U{sup 4+}{sub 0.447}Mn{sub 00.293}U{sup 6} {sup +}{sub 0.112}Y{sub 0.091}Zr{sub 0.023}Th{sub 0.011}){sub Σ0.977}(Fe{sup 3+}{sub 1.224}Fe{sup 2+}{sub 0.243}Mg{sub 0.023}P{sub 0.008}Si{sub 0.006} □{sub 0.496}){sub Σ2.000}(Ti{sub 12.464}Fe{sup 3+}{sub 5.292}V{sup 5+}{sub 0.118}Nb{sub 0.083}Al{sub 0.026}Cr{sup 3

  10. CE-BEMS

    DEFF Research Database (Denmark)

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

    2016-01-01

    Energy consumption in smart buildings is monitored and controlled using Building Energy Management Systems (BEMS). A BEMS provides a set of methods to monitor and control a building's energy needs while maintaining a good quality of living in all of the building's spaces. Energy efficiency...... 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...... savings in smart buildings. This system is connected to the cloud to have access to a number of advanced cloud-based services to enhance energy management in smart buildings. In this paper, we discuss the current limitations of BEMS, the conceptual design of the proposed system, and the advantages...

  11. CE and nanomaterials - Part II: Nanomaterials in CE.

    Science.gov (United States)

    Adam, Vojtech; Vaculovicova, Marketa

    2017-10-01

    The scope of this two-part review is to summarize publications dealing with CE and nanomaterials together. This topic can be viewed from two broad perspectives, and this article is trying to highlight these two approaches: (i) CE of nanomaterials, and (ii) nanomaterials in CE. The second part aims at summarization of publications dealing with application of nanomaterials for enhancement of CE performance either in terms of increasing the separation resolution or for improvement of the detection. To increase the resolution, nanomaterials are employed as either surface modification of the capillary wall forming open tubular column or as additives to the separation electrolyte resulting in a pseudostationary phase. Moreover, nanomaterials have proven to be very beneficial for increasing also the sensitivity of detection employed in CE or even they enable the detection (e.g., fluorescent tags of nonfluorescent molecules). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Effect of cerium on the corrosion behaviour of sintered (Nd,Ce)FeB magnet

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lijing [CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Bi, Mengxue [CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Nano Science and Technology Institute, University of Science and Technology of China, Hefei 230026 (China); Jiang, Jianjun; Ding, Xuefeng [CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhu, Minggang; Li, Wei [Functional Materials Research Institute, Central Iron & Steel Research Institute, Beijing 100081 (China); Lv, Zhongshan [Ningbo Shuo Teng new material Co., Ltd., Cixi 315301 (China); Song, Zhenlun, E-mail: songzhenlun@nimte.ac.cn [CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2017-06-15

    Highlights: • A little Ce could promote the magnets for a better corrosion resistance. • With increased Ce contents, the corrosion resistances of magnets decrease. • As the corrosion developed, the magnetic properties decreased. - Abstract: For the balanced consumption of rare-earth elements, cerium (Ce) was partially used for NdFeB magnets instead of Nd. The corrosion behaviour of the (Nd,Ce)FeB magnet with different Ce contents in 3.5% NaCl solution was investigated by SEM, XRD, EDS and electrochemical tests. After immersion, the weight loss was calculated and the magnetic properties of the samples were measured. Results showed that Ce affected the corrosion of the (Nd,Ce)FeB magnet. Compared with the NdFeB magnet without Ce but of the same grade as the magnetic energy product, (Nd,Ce)FeB magnet showed better corrosion resistance. With increased Ce content, the corrosion resistances and magnetic properties of (Nd,Ce)FeB magnets were investigated.

  13. 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.

  14. A estratégia de cluster na geração de vantagem competitiva : a fruticultura irrigada no agropólo do baxio Jaguaribe-CE

    OpenAIRE

    Alves, Eugenio Pacelli

    2003-01-01

    Baseando-se na literatura corrente relacionada à teoria dos Clusters econômicos e dos Sistemas Produtivos locais (SPL), a proposta deste trabalho consistiu em caracterizar e analisar a estrutura para produção de melão do AGROPÓLO do Baixo Jaguaribe, no norte do Ceará, onde é desenvolvida a fruticultura irrigada, enfatizando-se principalmente a capacidade de exportação sistemática e o grau de relacionamentos existentes entre os produtores rurais e alguns agentes externos ligados ao sistema ag...

  15. Opryszczkowe zapalenie mózgu przebiegające w postaci szybko narastającego zespołu otępiennego u chorej na reumatoidalne zapalenie stawów, leczonej infliksymabem

    Directory of Open Access Journals (Sweden)

    Justyna Swarowska-Knap

    2011-06-01

    Full Text Available Przedstawiono przypadek 53-letniej chorej na reumatoidalnezapalenie stawów (RZS o ciężkim, opornym na standardoweleczenie przebiegu, leczonej wieloma lekami modyfikującymi przebiegchoroby (LMPCh oraz glikokortykosteroidami, u którejw trakcie leczenia antycytokinowego (infliksymabem wystąpiłyobjawy szybko narastającego zespołu otępiennego. Ze względu nacoraz powszechniejsze zastosowanie leków antycytokinowych nietylko w dziedzinie reumatologii, coraz częściej w literaturze światowejpojawiają się doniesienia o związanych z ich stosowaniemdziałaniach niepożądanych, w tym powikłaniach infekcyjnychi zaburzeniach ze strony ośrodkowego układu nerwowego. Zaburzenianeurologiczne obserwowano w trakcie leczenia wszystkimiinhibitorami czynnika martwicy nowotworów α (tumour necrosisfactor α – TNF-α. Wśród nich występowały: parestezje (65% chorych,zaburzenia widzenia związane z zapaleniem nerwu wzrokowego(40% chorych i splątanie (25% chorych. Ponadto, wgdanych literaturowych, u chorych na RZS leczonych immunosupresyjnieistnieje większe niż w populacji ogólnej ryzyko poważnychinfekcji oraz reaktywacji latentnych infekcji wirusowych,w tym infekcji wirusami z rodziny Herpesviridae i wirusem JC. Ze względu na możliwy związek szybko ujawniających się zaburzeńneurologicznych z leczeniem infliksymabem wysunięto u pacjentkipodejrzenie postępującej wieloogniskowej leukoencefalopatii(progressive multifocal leukoencephalopathy – PML, będącej wynikiemaktywacji utajonej infekcji wirusem JC. W wykonanym badaniuMRI mózgowia stwierdzono obecność hiperintensywnychzmian zlokalizowanych w istocie białej oraz szarej płatów czołowychi skroniowych, które nie dawały efektu masy (ryc. 1. Lokalizacjazmian w płatach skroniowych była typowa dla opryszczkowegozapalenia mózgu (herpes simplex encephalitis – HSE, aleobecnie wiadomo, że podobne zmiany mogą także występowaćw PML. Obie neuroinfekcje mogą przebiega

  16. Active species of CeAl(4) in the CeCl(3)-doped sodium aluminium hydride and its enhancement on reversible hydrogen storage performance.

    Science.gov (United States)

    Fan, Xiulin; Xiao, Xuezhang; Chen, Lixin; Yu, Kairong; Wu, Zhe; Li, Shouquan; Wang, Qidong

    2009-11-28

    By directly doping CeAl(4) into sodium aluminium hydride, which probably serves as the active species in the hydriding and dehydriding processes of CeCl(3)-doped NaAlH(4), a high reversible hydrogen capacity of 4.77-4.92 wt% (close to expected capacity of 5.13 wt%) can be achieved in less than 20 min under moderate conditions.

  17. 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

  18. Uso da aspiração manual a vácuo na redução do custo e duração de internamentos por aborto incompleto em Fortaleza, CE, Brasil

    OpenAIRE

    Walter Fonseca; Chizuru Misago; Lucília Fernandes; Luciano Correia; Dirlene Silveira

    1997-01-01

    INTRODUÇÃO: O uso de aspiração a vácuo (AV) no tratamento do aborto incompleto é prática bastante difundida em países desenvolvidos. Vários estudos nesses países indicam que o uso da técnica de aspiração manual a vácuo (AMV) pode conservar recursos do sistema de saúde e melhorar a qualidade do tratamento do aborto. No Brasil, o uso da AMV é procedimento de rotina nos hospitais e clínicas privados. Entretanto, na maioria dos hospitais da rede pública é utilizada somente a técnica de dilatação ...

  19. 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

  20. A IMPORTÂNCIA DA EDUCAÇÃO FINANCEIRA NA TOMADA DE DECISÕES: UM ESTUDO COM OS SERVIDORES DO CENTRO ADMINISTRATIVO E FINANCEIRO (CAF DO MUNICÍPIO DE QUIXADÁ-CE

    Directory of Open Access Journals (Sweden)

    Bianca Almeida Cavalcante

    2014-06-01

    Full Text Available O presente estudo tem por objetivo relacionar a importância da Educação Financeira com o modo de controle das finanças pessoais, trazendo em pauta assuntos que influenciam diretamente o modo de o indivíduo se relacionar com o dinheiro. Para tanto, fez-se uso de pesquisa do tipo bibliográfica e pesquisa de campo, aplicando um questionário composto de 11 perguntas objetivas, com os servidores públicos do Centro Administrativo e Financeiro (CAF. No primeiro tópico foi explanada a influência do sistema capitalista no consumismo. Em seguida, no segundo tópico, são tratados os conceitos de Educação Financeira e Endividamento e a relação entre ambos. No terceiro tópico foram apresentados os dados obtidos na pesquisa de campo, bem como a análise dos gráficos. Ao final do estudo, concluiu-se que a Educação Financeira juntamente com um bom planejamento é uma excelente ferramenta para evitar situações de endividamento. Entretanto, a detenção do conhecimento não impossibilita que o indivíduo venha a somar as estatísticas de endividamento.

  1. Efeito da variação de pH na síntese e nas propriedades de BaCe0,2Pr0,8O3 obtido pelo método de complexação EDTA-citrato

    Directory of Open Access Journals (Sweden)

    M. F. Lobato

    2014-12-01

    Full Text Available Cerato de bário (BaCeO3 tem estrutura perovskita do tipo ABO3, na qual A e B são cátions metálicos. Estes materiais, dopados ou não, têm sido estudados por apresentarem características que os tornam promissores na aplicação em células a combustível de óxido sólido e permeação de hidrogênio e oxigênio. Porém, como os materiais cerâmicos de condutividade mista têm sido produzidos por métodos distintos de síntese, algumas condições influenciam diretamente as propriedades finais, sendo uma das mais importantes a dopagem do sítio B, que pode ter influência direta no tamanho de cristalito. Este trabalho teve como objetivo a substituição parcial do cério por 80% de praseodímio a partir do método de complexação, combinando EDTA-citrato, a fim de verificar a influência do pH da solução de síntese na obtenção da fase, nas propriedades cristalográficas e morfológicas. Foi verificado que o material apresenta estrutura cristalina ortorrômbica, com grupo espacial Pmcn e a fase foi obtida, independentemente da alteração no valor do pH da solução. Quanto ao tamanho de cristalito, com pH de síntese ajustado para 5, foi obtido maior valor, 352,7 nm, apesar de todos terem tido aumento em relação à amostra com pH corrigido para 11. Esse aumento se deu, provavelmente, pelo tempo insuficiente no qual a amostra foi submetida à ação da temperatura de síntese até a formação do gel final, ocasionando uma menor desagregação dos aglomerados formados na reação de complexação, resultado concordante com as análises de microscopia eletrônica de varredura.

  2. 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

  3. AVALIAÇÃO DA ROTULAGEM, CARACTERIZAÇÃO QUÍMICA, FÍSICO-QUÍMICA E REOLÓGICA DE NÉCTARES DE UVA COMERCIALIZADOS NA CIDADE DE FORTALEZA - CE

    Directory of Open Access Journals (Sweden)

    Alessandra Pinheiro de Góes CARNEIRO

    2013-04-01

    Full Text Available No Brasil, há diferentes tipos de bebidas de frutas, dentre elas pode-se citar o suco e o néctar, que, de acordo com a legislação brasileira diferem entre si na quantidade de polpa de fruta que é adicionada em cada formulação, sendo o néctar a bebida com menor proporção de polpa de fruta. O objetivo do presente trabalho foi avaliar diferentes marcas comerciais de néctar de uva quanto às características de rotulagem, propriedades químicas, físico-químicas e reológicas. O estudo foi realizado com dezesseis amostras de néctares de uva de diferentes marcas, sendo doze “tradicionais” e quatro “lights”, as quais foram obtidas em supermercados da cidade de Fortaleza, Ceará. Foram realizadas análises de pH, sólidos solúveis, acidez titulável, relação sólidos solúveis/acidez titulável, açúcares totais e redutores e ácido ascórbico. Apesar de 15% das amostras não apresentarem a denominação de venda do produto e 57% não continham o conteúdo líquido e o lote de fabricação descritos no rótulo, pode-se afirmar, que de um modo geral, os parâmetros analisados estão de acordo com o exigido pela legislação brasileira quanto à rotulagem e as características químicas e físico-químicas. Quanto às características reológicas, os néctares de uva classificam-se como fluidos newtonianos.

  4. Optimization of the time response of LaBr3(Ce) detectors, and its dependence on Ce concentration

    International Nuclear Information System (INIS)

    Vedia, V.; Mach, H.; Fraile, L.M.; Udias, J.M.; Lalkovski, S.

    2015-01-01

    Fast inorganic scintillators that exhibit good spectroscopy performance, like LaBr 3 (Ce), are the crystals of choice for many applications; they play a crucial role in the Ultra Fast Timing technique by virtue of their good energy resolution and fast response. This method, which is very sensitive to the LaBr 3 (Ce) time resolution, allows measurements of nuclear level lifetimes down to few ps range. There are indications that the nominal Ce concentration does strongly influence on the timing properties as well as it varies the photon yield and the energy resolution. In this work we have searched for the best settings in order to optimize the time resolution of three cylindrical LaBr 3 (Ce) detectors equipped with crystals identical in volume and shape but with different Ce dopant concentration. The time resolution of every detector depends on the proper selection of the fast photomultiplier tube and the set up parameters that can be further optimized by fine-tuning of the Constant Fraction Discrimination (CFD) and the PMT bias voltage. Very good time resolution can be obtained with the ORTEC 935 CFD for very short time-delays. Timing properties of the three crystals were studied by delayed coincidence measurements against a reference BaF 2 detector, whose time response is well known. The LaBr 3 (Ce) detector and the reference unit were placed in a close geometry with the radioactive source in between. We report timing results measured at the 60 Co and 22 Na energies. (author)

  5. Enhancing the blue shift of SHG signal in GaSe:B/Ce crystal

    Science.gov (United States)

    Karatay, Ahmet; Yuksek, Mustafa; Ertap, Hüseyin; Elmali, Ayhan; Karabulut, Mevlut

    2018-02-01

    The influence of Ce3+ on the wavelength of second harmonic generation (SHG) signal in boron doped GaSe crystals have been investigated. We found that by substitution of Ce3+ with B3+, SHG signal shifted to lower wavelength. In addition, the nonlinear absorption (NA) properties and ultrafast dynamics of pure, 1 at.% B3+ and 0.5 at.% B3++ 0.5 at.% Ce3+ doped GaSe crystals have been studied by open aperture Z-scan and ultrafast pump probe spectroscopy techniques. From the open aperture Z-scan experiments we observed that all of the crystals showed nonlinear absorption (NA). However, pump-probe experiments revealed that when GaSe crystal is doped, the NA signal turns into a bleaching signal with different lifetimes depending on the type and concentration of the dopant atoms.

  6. '-----RESO-NA---:"N-CE":"'-IDe-Ce-m-be--'2-00-5

    Indian Academy of Sciences (India)

    leadership, a major centre of cosmic 'ray research covering practically all aspects of the radiation and continues to be active in this field. Homi Bhabha is well known among the scientists of India and the public at large as the 'Father of India's Atomic Energy. Programme'. What is not so well known however,. particularly.

  7. '-----RESO-NA---:"N-CE":"'-IDe-Ce-m-be--'2-00-5

    Indian Academy of Sciences (India)

    Cosmic rays are very high energy particles arriving from the depths of space and incident on the earth's atmosphere at all places and at all times. The energy of these particles extends over 12 decades from around 10' ev to lOll ev and mercifully for the survival of life, the intensity falls by atleast 22 decades &om about 100 ...

  8. Prevzdelanost' na českom trhu práce

    OpenAIRE

    Laslopová, Ľubica

    2015-01-01

    In one way or another, labour market theories link additional years of edu- cation to better jobs and higher earnings. The empirical research, however, identified systematic distortions of this rule. Some workers are considered to be overeducated, as their education exceeds the level required for their job. This thesis deals with overeducation in the Czech labour market, as there are still few studies considering this topic. First we estimate incidence of overedu- cation using objective measu...

  9. Założenia rekreacji terapeutycznej i jej rola na podstawie badań przeprowadzonych w wakacyjnym ośrodku rekreacyjnym Barretstown dla dzieci cierpiących na choroby przewlekłe i zagrażające życiu

    OpenAIRE

    Joanna Kondracka

    2013-01-01

    Wraz z postępem medycyny maleje liczba dzieci umierających na poważne choroby somatyczne, takie jak nowotwory, białaczka, choroby układu odpornościowego. Jednocześnie wzrasta liczba dzieci, które latami żyją z poważną, prze‑ wlekłą chorobą i na co dzień borykają się ze skutkami ubocznymi długoterminowego leczenia, niemożnością uczest‑ nictwa w normalnych aktywnościach swych rówieśników, ze swoją odmiennością i stałym poczuciem zagrożenia. Do takich właśnie dzieci adresowane są org...

  10. Hematite (α-Fe2O3) - A potential Ce4+ carrier in red mud.

    Science.gov (United States)

    Bolanz, Ralph M; Kiefer, Stefan; Göttlicher, Jörg; Steininger, Ralph

    2018-05-01

    Cerium is the most abundant rare earth element (REE) within the waste product of alumina production (red mud), but its speciation in this complex material is still barely understood. Previous studies showed evidence for a correlation between Ce and the main constituent of red mud, iron oxides, which led us to investigate the most abundant iron oxide in red mud, hematite, as possible carrier phase for Ce. Synthetic hematite can incorporate up to 1.70±0.01wt% Ce, which leads to a systematical increase of all unit cell parameters. Investigations by extended X-ray absorption fine structure spectroscopy suggest an incorporation of Ce 4+ O 6 into the hematite structure by a novel atomic arrangement, fundamentally different from the close-range order around Fe 3+ in hematite. Samples of red mud were taken in Lauta (Saxony), Germany and analyzed by powder X-ray diffraction, inductively coupled plasma mass and optical emission spectrometry, electron microprobe analysis and X-ray absorption near-edge structure spectroscopy. Red mud samples consist of hematite (Fe 2 O 3 ) (34-58wt%), sodalite (Na 8 Al 6 Si 6 O 24 Cl 2 ) (4-30wt%), gibbsite (Al(OH) 3 ) (0-25wt%), goethite (FeOOH) (10-23wt%), böhmite (AlOOH) (0-11wt%), rutile (TiO 2 ) (4-8wt%), cancrinite (Na 6 Ca 2 Al 6 Si 6 O 24 (CO 3 ) 2 ) (0-5wt%), nordstrandite (Al(OH) 3 ) (0-5wt%) and quartz (SiO 2 ) (0-4wt%). While the main elemental composition is Fe>Al>Na>Ti>Ca (Si not included), the average concentration of REE is 1109±6mg/kg with an average Ce concentration of 464±3mg/kg. The main carrier of Ce was located in the Fe-rich fine-grained fraction of red mud (0.10wt% Ce 2 O 3 ), while other potential Ce carriers like monazite, lead oxides, secondary Ce-minerals and particles of potentially anthropogenic origin are of subordinated relevance. Cerium in red mud occurs predominantly as Ce 4+ , which further excludes Ce 3+ minerals as relevant sources. Copyright © 2017. Published by Elsevier B.V.

  11. Photoluminescence and radiation response properties of Ce3+-doped CsCaCl3 crystalline scintillator

    Science.gov (United States)

    Fujimoto, Yutaka; Saeki, Keiichiro; Tanaka, Hironori; Yahaba, Takuma; Yanagida, Takayuki; Koshimizu, Masanori; Asai, Keisuke

    2016-09-01

    In this paper, we report on the photoluminescence and scintillation properties of a newly developed CsCaCl3:Ce (0.5 mol%) crystalline scintillator grown by the vertical Bridgman method. The fluorescence quantum efficiency for the Ce3+ characteristic emission bands centered at around 350-400 nm was 76% under excitation at 330 nm light. The photoluminescence decay time of the Ce3+ was approximately 32 ns. When x-ray excited the crystal, intense emission bands were observed at 350-400 nm, and could be attributed to the Ce3+ emission. The scintillation light yield of the developed crystal was ˜7600 ph MeV-1 compared to a NaI:Tl commercial scintillator, and the principal scintillation decay time was approximately 340 ns plus two fast components of around 1.6 ns and 45 ns.

  12. Photoluminescence and radiation response properties of Ce3+-doped CsCaCl3 crystalline scintillator

    International Nuclear Information System (INIS)

    Fujimoto, Yutaka; Saeki, Keiichiro; Tanaka, Hironori; Yahaba, Takuma; Koshimizu, Masanori; Asai, Keisuke; Yanagida, Takayuki

    2016-01-01

    In this paper, we report on the photoluminescence and scintillation properties of a newly developed CsCaCl 3 :Ce (0.5 mol%) crystalline scintillator grown by the vertical Bridgman method. The fluorescence quantum efficiency for the Ce 3+ characteristic emission bands centered at around 350–400 nm was 76% under excitation at 330 nm light. The photoluminescence decay time of the Ce 3+ was approximately 32 ns. When x-ray excited the crystal, intense emission bands were observed at 350–400 nm, and could be attributed to the Ce 3+ emission. The scintillation light yield of the developed crystal was ∼7600 ph MeV −1 compared to a NaI:Tl commercial scintillator, and the principal scintillation decay time was approximately 340 ns plus two fast components of around 1.6 ns and 45 ns. (paper)

  13. Preparation of Mg-doped Ce-Zr Solid Catalysts and Their Catalytic ...

    African Journals Online (AJOL)

    NICO

    Knoevenagel condensation using aromatic aldehydes and 2,4-thiazolidinedione in ethanol:water medium. The best catalytic activity was ... Addition of MgO to the Ce-Zr mixed metal oxides affected both particle size and catalytic activity. KEYWORDS ... piperidine in EtOH,9 NaOAc in DMF-AcOH10, ethylene- diammonium ...

  14. Kostel na Lesné

    OpenAIRE

    Pospíšil, Vojtěch

    2017-01-01

    Tato teoretická diplomová práce se zabývá prostorovou akustikou a s tím úzce spojenou problematikou doby dozvuku. Součástí práce je zpracování návrhu akustických úprav kostela na základě ručního výpočtu, který byl dále upravován ve specializovaném softwaru Odeon Room Acoustics Program. Pro okolní zástavbu kostela byla vytvořena hluková studie v programu Hluk+, aby bylo posouzeno, jaký bude mít tato novostavba hlukový dopad z kostelních zvonů dopad na své okolí. Na základě specializace, bylo v...

  15. 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)

  16. Emission and excitation spectra of Ce3+ and Pr3+ ions in hexafluoroelpasolite lattices.

    Science.gov (United States)

    Duan, Chang-Kui; Tanner, Peter A; Makhov, Vladimir; Khaidukov, Nicholas

    2011-08-18

    The emission and excitation spectra of Ce(3+) and Pr(3+) doped into the cubic host Cs(2)NaYF(6) have been recorded at room temperature and ∼10 K using synchrotron radiation. The two 5d(1) T(2g) states of Ce(3+) have been located from the excitation spectra, whereas the E(g) state is placed above the host band gap. Decay measurements of the 5d(1) → 4f(1) Ce(3+) emission, and spectra collected using selective excitation, indicate the occupation of more than one type of site by Ce(3+) in this host lattice. By contrast, the location of features in the 4f(1)5d(1) → 4f(2) emission of Pr(3+) is independent of the excitation wavelength. Assignments are presented for some of the 4f(1)5d(1) levels and for the Pr(3+)-F(-) charge transfer band. The 5d emission lifetimes for Ce(3+) and Pr(3+) in the Cs(2)NaYF(6) host are 42 and 29 ± 1 ns, respectively, and are not temperature-dependent. © 2011 American Chemical Society

  17. Tetravalent Ce in the Nitrate-Decorated Hexanuclear Cluster [Ce 63 -O) 43 -OH) 4 ] 12+ : A Structural End Point for Ceria Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Estes, Shanna L.; Antonio, Mark R.; Soderholm, L.

    2016-03-17

    We describe the synthesis and characterization of three glycine-stabilized hexanuclear Cely cluster compounds, each containing the [Ce-6(mu(3)-O)(4)(mu(3)-OH)(4)](12+) core structure. Crystallized from aqueous nitrate solutions with pH < 0, the core cluster structures exhibit variable decoration by nitrate, glycine, and water ligands depending on solution conditions, where increased nitrate and glycine decoration of the cluster core was observed for crystals synthesized at high Ce and nitrate concentrations. No other crystalline products were observed using this synthetic route. In addition to confirming the tetravalent oxidation state of cerium in one of the reported clusters, cyclic voltammetry also indicates that Ce-IV is reduced at similar to+0.60 V vs Ag/AgCl (3 M NaCl), which is significantly less than the standard electrode potential. This large decrease in the Ce-IV/Ce-III reduction potential suggests that Ce-IV is significantly stabilized relative to Ce-III within the examined cluster. These compounds are discussed in terms of their importance as small, end member, ceric oxide nanoparticles. Single-crystal structural solutions, together with voltammetry and electrolysis data, permit the decoupling of Ce-III defects and substoichiometry. In addition, Ce-Ce distances can be used to determine an "effective" CeO2-x lattice constant, providing a simple method for comparing literature descriptions. The results are discussed in terms of their potential implications for the mechanisms by which nanoparticle ceria serve as catalysts and oxygen-storage materials.

  18. Improvement on the light yield of a high-Z inorganic scintillator GSO(Ce)

    CERN Document Server

    Kamae, T; Isobe, N; Kokubun, M; Kubota, A; Osone, S; Takahashi, T; Tsuchida, N; Ishibashi, H

    2002-01-01

    Cerium-doped gadolinium silicic dioxide crystal, GSO(Ce), is a high-Z non-hydroscopic scintillator that gives higher light yield than BGO, and can potentially replace NaI(Tl), CsI(Tl) and BGO in many applications. Its production cost, however, has been substantially higher than any of them, while its energy resolution has been worse than that of NaI(Tl) or CsI(Tl). The merit did not overcome these deficiencies except in limited applications. We developed a low background phoswich counter (the well-type phoswich counter) for the Hard X-ray Detector of the Astro-E project based on GSO scintillator. In the developmental work, we have succeeded in improving the light yield of GSO(Ce) by 40-50%. For energies above 500 keV, a large GSO(Ce) crystal (4.5 cmx4.5phi cm) now gives energy resolution comparable to or better than the best NaI(Tl) when read out with a phototube. With a small GSO(Ce) crystal (5x5x5 mm sup 3) and a photodiode, an energy resolution comparable to or better than the best CsI(Tl) has been obtaine...

  19. Electrochemical methods for corrosion testing of Ce-based coating prepared on AA6060 alloy by dip immersion method

    Directory of Open Access Journals (Sweden)

    Jegdić Bore V.

    2013-01-01

    Full Text Available Dip-immersion is simple and cost-effective method for the preparation of Ce-based conversion coatings (CeCCs, a promising alternative to the toxic chromate coatings, on the metal substrates. In this work CeCCs were prepared on Al-alloy AA6060 from aqueous solution of cerium chloride at room temperature. Effect of immersion time and post-treatment in phosphate solution on the microstructure and corrosion properties of the coatings was studied. The longer immersion time, the thicker but nonhomogeneous and cracked CeCCs. The post-treatment contributed to the sealing of cracks, as proven by an increase in corrosion resistance compared with as-deposited coatings. CeCCs prepared at longer deposition time and post-treated showed much better corrosion protection than those prepared at short deposition time. A detailed EIS study was undertaken to follow the evolution of corrosion behaviour of CeCCs with time of exposure to aggressive chloride environment (3.5 % NaCl. For the sake of comparison, the EIS properties of bare AA6060 were also investigated. A linear voltammetry was performed to complete the study. Results confirmed a formation of protective CeCCs on AA6060 surface. However, even CeCCs prepared at longer deposition time and post-treated provided a short term protection in aggressive environment, due to the small thickness. [Projekat Ministarstva nauke Republike Srbije, br. III 45019 i br. III 45012

  20. Chemically abrupt interface between Ce oxide and Fe films

    International Nuclear Information System (INIS)

    Lee, H.G.; Lee, D.; Kim, S.; Kim, S.G.; Hwang, Chanyong

    2005-01-01

    A chemically abrupt Fe/Ce oxide interface can be formed by initial oxidation of an Fe film followed by deposition of Ce metal. Once a Ce oxide layer is formed on top of Fe, it acts a passivation barrier for oxygen diffusion. Further deposition of Ce metal followed by its oxidation preserve the abrupt interface between Ce oxide and Fe films. The Fe and Ce oxidation states have been monitored at each stage using X-ray photoelectron spectroscopy

  1. Pyrazolates advance cerium chemistry: a CeIII/CeIV redox equilibrium with benzoquinone.

    Science.gov (United States)

    Werner, Daniel; Deacon, Glen B; Junk, Peter C; Anwander, Reiner

    2017-05-16

    Two stable cerium(iv) 3,5-dialkylpyrazolate complexes are presented, namely dimeric [Ce(Me 2 pz) 4 ] 2 (Me 2 pz = 3,5-dimethylpyrazolate) and monomeric Ce(tBu 2 pz) 4 (tBu 2 pz = 3,5-di-tert-butylpyrazolate) along with their trivalent counterparts [Ce(Me 2 pz) 3 ] and [Ce(tBu 2 pz) 3 ] 2 . All complexes were obtained from protonolysis reactions employing the silylamide precursors Ce[N(SiHMe 2 ) 2 ] 4 and Ce[N(SiMe 3 ) 2 ] 3 . Treatment of homoleptic Ce IV and Ce III Me 2 pz complexes with 1,4-hydroquinone (H 2 hq) or 1,4-benzoquinone (bq), respectively, ultimately gave the same trimetallic Ce III species via a cerium redox equilibrium. The Ce III complex Ce 3 (Me 2 pz) 5 (pchd) 2 (L) (pchd = 1,4-bis(3,5-dimethylpyrazol-1-yl)cyclohex-2,5-diene-1,4-diolato; L = Me 2 pzH or (thf) 2 ) results from a di-1,4-pyrazolyl attack on pre-coordinated bq. The reduction of bq by [Ce(Me 2 pz) 3 (thf)] 2 , and re-oxidation by the resulting Ce IV species was supported by UV-vis spectroscopic investigations. Comparisons with the redox-innocent complexes [Ln(Me 2 pz) 3 (thf)] 2 (Ln = La and Pr) revealed far less selective reactions with bq, giving hexametallic and octametallic rare-earth metal side products containing 2-Me 2 pz substituted hq ligands.

  2. Uso da aspiração manual a vácuo na redução do custo e duração de internamentos por aborto incompleto em Fortaleza, CE, Brasil Adoption of manual vacuum aspiration for treatment of incomplete abortion reduces costs and duration of patient's hospital stay in an urban area of Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Walter Fonseca

    1997-10-01

    Full Text Available INTRODUÇÃO: O uso de aspiração a vácuo (AV no tratamento do aborto incompleto é prática bastante difundida em países desenvolvidos. Vários estudos nesses países indicam que o uso da técnica de aspiração manual a vácuo (AMV pode conservar recursos do sistema de saúde e melhorar a qualidade do tratamento do aborto. No Brasil, o uso da AMV é procedimento de rotina nos hospitais e clínicas privados. Entretanto, na maioria dos hospitais da rede pública é utilizada somente a técnica de dilatação e curetagem (D&C. METODOLOGIA: Foram utilizados métodos de avaliação rápida para estimar a variação do custo médio do tratamento e duração da estadia hospitalar, em um grupo de 30 pacientes admitidas com aborto incompleto em hospital público de Fortaleza, CE (Brasil. Participantes foram alocadas, randomicamente, em um dos dois grupos de tratamento investigados (AMV ou D&C. RESULTADOS E CONCLUSÕES: Os resultados sugerem que o uso da AMV, em substituição a D&C, no tratamento do aborto incompleto, pode reduzir em até 41% o custo médio do tratamento e em 77% o tempo médio de hospitalização. Recomenda-se a realização de estudos confirmatórios, como também que se aprofunde os conhecimentos sobre a percepção do aborto e seu tratamento por parte do pessoal de saúde e da população feminina.INTRODUCTION: In most developed countries vacuum aspiration has been shown to be safer and less costly than sharp curettage (SC for uterine evacuation. In many of the developing countries, including Brazil, sharp curettage (SC is the most commonly used technique for treating cases of incomplete abortion admitted to hospital. The procedure often involves light to heavy sedation for pain control and an overnight hospital stay for patient recuperation and monitoring. Two hypotheses are examined: the first, that the use of manual vacuum aspiration (MVA - a variation of the vacuum aspiration, would be less costly than SC for the treatment

  3. Catalisadores de Cu/CeO2 modificados com La aplicados à reação de deslocamento gás-água

    OpenAIRE

    Tatiana de Freitas Silva

    2013-01-01

    A reação de deslocamento gás-água (water gas shift reaction, WGSR) é frequentemente usada em processos industriais para aumentar a produção de hidrogênio, assim como para remover quantidades de CO das correntes produzidas pela reforma a vapor de hidrocarbonetos. Neste trabalho, foram preparados catalisadores CuO/CeO2 e CuO/CeO2-La2O3 para a aplicação na reação de deslocamento gás-água. Os suportes CeO2 e CeO2-La2O3 foram preparados por três métodos diferentes: Hidrotérmico (CeO2(H) e CeO2-La2...

  4. (EC+β+) decay of 130Ce

    International Nuclear Information System (INIS)

    Xu Shuwei; Zhang Tianmei; Xie Yuanxiang; Ma Ruichang; Ge Yuanxiu; Guo Yingxiang; Wang Chunfang; Li Zhankui; Guo Bing; Xing Jianping; Guo Tianrui; Zhu Shaofei; Xu Wang; Du Jinzhou

    1996-01-01

    The nuclide 130 Ce was produced by a ( 16 O, 4n) reaction on an enriched 118 Sn target. Reaction products were transported to a shielded location by using a helium-jet tape transport system. A 22.9 min activity in chemically separated cerium sample was identified as 130 Ce. The (EC+β + ) decay scheme of 130 Ce was proposed for the first time. This scheme includes 108 γ-lines, 107 γ-lines among them being new. More than 13 1 + low-lying states of 130 La are populated in the decay of 130 Ce. Two new isomers with half-life of 77±10 ns and 17±5 ns were observed by means of delayed γ-γ coincidence measurements. (orig.). With 5 figs., 3 tabs

  5. Solute diffusion in Pu and Ce

    International Nuclear Information System (INIS)

    Marbach, Gabriel; Charissoux, Christian; Janot, Christian

    1976-01-01

    The diffusion rate of Co, Au and Ag in the bcc phases of Pu and Ce is studied. In the bcc delta phase of Pu, Au and Ag have the same diffusion rate that the matrix and Co is a very rapid solute. In the bcc phase of Ce, the diffusion coefficients of the three metals are remarkably high. This phenomenon is also observed in certain metallic matrices (Pb, Sn, [fr

  6. Metamagnetism in Ce(Ga,Al)2

    Indian Academy of Sciences (India)

    Abstract. Effect of Al substitution on the magnetic properties of Ce(Ga1−x Alx )2 (x = 0, 0.1 and. 0.5) system has been studied. The magnetic state of CeGa2 is found to be FM with a TC of 8 K, whereas the compounds with x =0.1 and 0.5 are AFM and possess TN of about 9 K. These two com- pounds undergo metamagnetic ...

  7. Ce O2-Zr O2 tetragonal ceramics (Ce-TZP): mechanical properties

    International Nuclear Information System (INIS)

    Nono, Maria do Carmo de Andrade

    1994-01-01

    This work presents the development and the characterization of Ce O 2 -stabilized tetragonal Zr O 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 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)

  8. A new type of Ce-Mo based conversion coatings for aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Li Di; Li Guoqiang; Guo Baolan; Peng Mingxia [Coll. of Materials Science and Engineering, Beijing Univ. of Aeronautics and Astronautics, Beijing, BJ (China)

    2002-07-01

    A new type of process for forming Ce-Mo conversion coatings on Al-alloys has been developed. Conversion coatings about 3.6 {mu}m thickness were obtained by immersing Al-alloys for 20 minutes in boiling film forming solutions containing (NH{sub 4}){sub 2}Ce(NO{sub 3}){sub 6} 2.5 g/l, NaKC{sub 4}H{sub 4}O{sub 6}.4H{sub 2}O 2.5 g/l, Na{sub 2}CO{sub 3} 7.5 g/l and Na{sub 2}MoO{sub 4} 5.0 g/l. In the case of LF4 Al-alloy, polarization curves and immersion tests in 5% NaCl indicated that the conversion coatings exhibited more excellent resistance to localized corrosion than the conventional chromate conversion coatings. However, its resistance to localized corrosion was not satisfactory on LC4 Al alloy. Scanning electron microscopy (SEM) and energy dispersion analyzer of X-ray (EDAX) analysis revealed that the conversion coatings having complex surface microstructure on both LC4 and LF6 Al alloys consist mainly of O, Al and other alloying elements in addition to significant Ce and Mo. A mechanism of film formation was proposed to explain the experimental results. (orig.)

  9. Evaluation of Ce3+ and alkali metal ions Co-doped LiSrAlF6 crystalline scintillators

    International Nuclear Information System (INIS)

    Wakahara, Shingo; Yanagida, Takayuki; Fujimoto, Yutaka; Yokota, Yuui; Pejchal, Jan; Kurosawa, Shunsuke; Suzuki, Shotaro; Kawaguchi, Noriaki; Fukuda, Kentaro; Yoshikawa, Akira

    2013-01-01

    High scintillation efficiency of Eu-doped LiSrAlF 6 (LiSAF) and LiCaAlF 6 (LiCAF) codoped with alkali metal ions has been reported in our recent studies. Thus in this paper, we demonstrated the scintillation properties of 1% Ce-doped LiSAF crystals with 1% alkali metal ions co-doping to increase the light yield and understand the scintillation mechanism. The crystals showed intense emission band corresponding to the 5d-4f transition of Ce 3+ , and their light yields under thermal neutron excitation were higher than that of the Ce only doped crystal. Especially, the light yield of Ce–Na co-doped crystal exceeded about two times that of Ce only doped one. -- Highlights: ► Ce-doped and alkali metal co-doped LiSAF crystals were grown by μ-PD method. ► Alkali metal co-doped crystals showed higher light yield than Ce only doped crystal. ► Decay time of alkali metal co-doped LiSAF were longer than that of Ce only doped one

  10. Fabrication of Nano-CeO2 and Application of Nano-CeO2 in Fe Matrix Composites

    International Nuclear Information System (INIS)

    Tiebao, W.; Chunxiang, C.; Xiaodong, W.; Guobin, L.

    2010-01-01

    It is expatiated that nano-CeO2 is fabricated by the direct sedimentation method. The components and particles diameter of nano-CeO2 powders are analyzed by XRD and SEM . The thermodynamic analysis and acting mechanism of nano-CeO2 with Al in Fe matrix composites are researched, which shows that the reaction is generated between CeO2 and Al in the composite, that is, 3CeO2+4Al - 2Al2O3+3[Ce], which obtains Al2O3 and active [Ce] during the sintering process. The active [Ce] can improve the performance of CeO2/Fe matrix composites. The suitable amount of CeO2 is about 0.05% in CeO2/Fe matrix composites. SEM fracture analysis shows that the toughness sockets in nano-CeO2/Fe matrix composites are more than those in no-added nano-CeO2 composites, which can explain that adding nano-CeO2 into Fe matrix composite, the toughness of the composite is improved significantly. Applied nano-CeO2 to Fe matrix diamond saw blades shows that Fe matrix diamond saw blade is sharper and of longer cutting life than that with no-added nano-CeO2.

  11. Physico-chemical properties of (U,Ce)O2

    International Nuclear Information System (INIS)

    Yamada, K.; Yamanaka, S.; Katsura, M.

    1998-01-01

    The high-temperature X-ray diffraction analysis of (U,Ce)O 2 with CeO 2 contents ranging from 0 to 20 mol.% CeO 2 was performed to obtain the variation of the linear thermal expansion coefficient with the CeO 2 content. Ultrasonic pulse-echo measurements were also carried out from room temperature to 673 K to estimate the change in the mechanical properties of (U,Ce)O 2 with the CeO 2 content. The variation in the linear thermal expansion coefficient at the low CeO 2 content region is more steep than that expected from the linear thermal expansion coefficient of UO 2 and CeO 2 . The Young's and shear moduli of all (U,Ce)O 2 were found to decrease with rising temperature. This was due to the increase of the bond length accompanied by the thermal expansion. Although the lattice parameter decreased with CeO 2 content, the moduli of (U,Ce)O 2 were found to decrease with increasing CeO 2 content at room temperature. These results show that in the range from 0 to 20 mol.% of CeO 2 , as CeO 2 content increases, the bottom of the potential energy in (U,Ce)O 2 is shallower and broader. (orig.)

  12. 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.

  13. Renormalized electronic structures of CeSi{sub 2}, CeRu{sub 2} and CeAl{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Costa-Quintana, J. [Universitat Autonoma de Barcelona (Spain). Grup d`Electromagnetisme; Gonzalez-Leon, E. [Universitat Autonoma de Barcelona (Spain). Grup d`Electromagnetisme; Lopez-Aguilar, F. [Universitat Autonoma de Barcelona (Spain). Grup d`Electromagnetisme; Puig-Puig, L. [Universitat Autonoma de Barcelona (Spain). Grup d`Electromagnetisme; Sanchez-Lopez, M.M. [Universitat Autonoma de Barcelona (Spain). Grup d`Electromagnetisme

    1995-02-01

    The renormalized density of states of some Ce compounds is analyzed by considering self-energy effects. We study the influence of the hybridization introduced by the self-energy and how it can affect the shape of the characteristic lower, upper and middle-energy resonance. ((orig.)).

  14. Broadband Ce(III)-Sensitized Quantum Cutting in Core-Shell Nanoparticles: Mechanistic Investigation and Photovoltaic Application.

    Science.gov (United States)

    Sun, Tianying; Chen, Xian; Jin, Limin; Li, Ho-Wa; Chen, Bing; Fan, Bo; Moine, Bernard; Qiao, Xvsheng; Fan, Xianping; Tsang, Sai-Wing; Yu, Siu Fung; Wang, Feng

    2017-10-19

    Quantum cutting in lanthanide-doped luminescent materials is promising for applications such as solar cells, mercury-free lamps, and plasma panel displays because of the ability to emit multiple photons for each absorbed higher-energy photon. Herein, a broadband Ce 3+ -sensitized quantum cutting process in Nd 3+ ions is reported though gadolinium sublattice-mediated energy migration in a NaGdF 4 :Ce@NaGdF 4 :Nd@NaYF 4 nanostructure. The Nd 3+ ions show downconversion of one ultraviolet photon through two successive energy transitions, resulting in one visible photon and one near-infrared (NIR) photon. A class of NaGdF 4 :Ce@NaGdF 4 :Nd/Yb@NaYF 4 nanoparticles is further developed to expand the spectrum of quantum cutting in the NIR. When the quantum cutting nanoparticles are incorporated into a hybrid crystalline silicon (c-Si) solar cell, a 1.2-fold increase in short-circuit current and a 1.4-fold increase in power conversion efficiency is demonstrated under short-wavelength ultraviolet irradiation. These insights should enhance our ability to control and utilize spectral downconversion with lanthanide ions.

  15. Ce-valence state and hydrogen-induced volume effects in Ce-based intermetallic compounds and their hydrides

    International Nuclear Information System (INIS)

    Stange, M.; Paul-Boncour, V.; Latroche, M.; Percheron-Guegan, A.; Isnard, O.; Yartys, V.A.

    2005-01-01

    An average Ce-valence state (v) of two types of Ce-containing intermetallic compounds, equiatomic CeNiX (X= Al, Ga, Sn) and CeM 3 (M= Ni, Co, Mn), and their hydrides was estimated from X-ray absorption spectroscopy (XAS) and analysed in parallel with hydrogen-induced volume changes on hydrogenation. The largest valence states in the initial compounds were found in CeM 3(v=3.32-3.36) followed by CeNiAl 1-x Ga x (v=3.25-3.27). This contrasts to CeNiSn, which is close to a pure trivalent state (v=3.07). On hydrogenation, a conversion from mixed-valent CeNiAl 1-x Ga x , x=0.5, 1, to pure Ce III hydrides takes place (ΔV /V=19.6-20.0 %). In CeNiSnD z (z=1, 1.8, ΔV/V=3.0, 8.0%) the changes in the valence state towards Ce III are very small. The situation for the CeM 3 -hydrides is complex. For CeNi 3 D 2.8 , CeNi 2.75 Mn 0.25 D 3.4 and CeCo 3 D 3.4 (ΔV /V=24-32%) where rather similar electronic properties can be expected, a decrease in the contribution of Ce IV for CeNi 3 D 3 and CeNi 2.75 Mn 0.25 D 3.4 (v=3.18 and 3.12, respectively) contrasts to the behaviour of CeCo 3 D 3.4 where the hydrogen induced valence change is very small (v=3.32)

  16. CeO2-stabilized tetragonal ZrO2 polycrystals (Ce-TZP ceramics)

    International Nuclear Information System (INIS)

    Andrade Nono, M.C. de.

    1990-12-01

    This work presents the development and the characterization of CeO 2 -stabilized tetragonal ZrO 2 polycrystals (Ce-TZP ceramics), since it is considered candidate material for applications as structural high performance ceramics. Sintered ceramics were fabricated from mixtures of powders containing different CeO 2 content prepared by conventional and nonconventional techniques. These powders and their resultant sintered ceramics were specified by chemical and physical characterization, compactation state and mechanical properties. The chemical characteristics were determined by chemical analysis and the physical characteristics were evaluated by phase content, particle and agglomerate size and aspect, and powder porosity. (author)

  17. Production of 139Ce by the 139La(p,n)139Ce reaction

    International Nuclear Information System (INIS)

    Ishioka, Noriko S.; Sekine, Toshiaki; Izumo, Mishiroku; Hashimoto, Kazuyuki; Kobayashi, Katsutoshi; Matsuoka, Hiromitsu

    2002-01-01

    To produce a carrier-free 139 Ce to be used as an efficiency-calibration source for Ge detectors, a target-preparation method and a chemical separation method were studied. It was found that commercially available powders of lanthanum-oxide and lanthanum metal are applicable to a target material in the nuclear reaction 139 La(p,n) 139 Ce. In the separation of 139 Ce from an irradiated lanthanum target, a solvent-extraction method and an ion-exchange method gave final products in good chemical purity. (author)

  18. Microneedle Array Interface to CE on Chip

    NARCIS (Netherlands)

    Lüttge, Regina; Gardeniers, Johannes G.E.; Vrouwe, E.X.; van den Berg, Albert; Northrup, M.A.; Jensen, K.F; Harrison, D.J.

    2003-01-01

    This paper presents a microneedle array sampler interfaced to a capillary electrophoresis (CE) glass chip with integrated conductivity detection electrodes. A solution of alkali ions was electrokinetically loaded through the microneedles onto the chip and separation was demonstrated compared to a

  19. Metamagnetism in Ce(Ga,Al)2

    Indian Academy of Sciences (India)

    Metamagnetism in Ce(Ga,Al)2. K G SURESH1,∗. , S RADHA2 and A K NIGAM3. 1Department of Physics, Indian Institute of Technology, Mumbai 400 076, India. 2Department of Physics, Mithibai College, Mumbai 400 056, India. 3Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India. ∗.

  20. (Ln = Ce, Pr and Nd) microwave ceramics

    Indian Academy of Sciences (India)

    125–128. c Indian Academy of Sciences. Influence of lead oxide addition on LnTiTaO6 (Ln = Ce, Pr and Nd) ... A number of samples with improved microwave dielectric properties were obtained on all the systems suitable for practical ... circuits due to their compactness, thermal stability, low cost of production, high efficiency ...

  1. 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.

  2. Crystal structures of isotypic aluminides CeRuAl and CeRhAl

    International Nuclear Information System (INIS)

    Gribanov, A.V.; Tursina, A.I.; Grytsiv, A.V.; Murashova, E.V.; Bukhan'ko, N.G.; Rogl, P.; Seropegin, Y.D.; Giester, G.

    2008-01-01

    The crystal structures of the compounds CeRuAl and CeRhAl were studied by single crystal X-ray diffraction. Both compounds crystallize in the orthorhombic LaNiAl type with space group Pnma (No. 62) and are related to the structure types of hexagonal ZrNiAl and orthorhombic TiNiSi. Parameters for CeRuAl and CeRhAl are: a = 7.2057(2) A, b = 4.0589(1) A, c = 15.8728(5) A; R F = 0.023; a = 7.107(2) A, b = 4.2237(10) A, c = 15.965(3) A; R F 0.032, respectively

  3. Tuning Ce distribution for high performanced Nd-Ce-Fe-B sintered magnets

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Xiaodong [School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048 (China); Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); Guo, Shuai; Chen, Kan; Chen, Renjie; Lee, Don [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); You, Caiyin, E-mail: caiyinyou@xaut.edu.cn [School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048 (China); Yan, Aru, E-mail: aruyan@nimte.ac.cn [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China)

    2016-12-01

    A dual-alloy method was applied to tune the distribution of Ce for enhancing the performance of Nd-Ce-Fe-B sintered magnets with a nominal composition of (Nd{sub 0.75}Ce{sub 0.25}){sub 30.5}Fe{sub bal}Al{sub 0.1}Cu{sub 0.1}B. In comparison to the single alloy of (Nd{sub 0.75}Ce{sub 0.25}){sub 30.5}Fe{sub bal}Al{sub 0.1}Cu{sub 0.1}B, the coercivity was enhanced from 10.3 kOe to 12.1 kOe and the remanence was increased from 13.1 kG to 13.3 kG for the magnets with a dual-alloy method. In addition, the remanence temperature coefficient α and coercivity temperature coefficient β were also slightly improved for the magnet with the dual alloys. The results of microstructure characterizations show the uniform distribution of Ce for the magnet with a single alloy, and the coexistence of the Ce-rich and Ce-lean regions for the magnet with the dual alloys. In combinations with the nucleation of reversal domains and magnetic recoil curves, the property enhancement of magnets with a dual-alloy method was well explained. - Highlights: • Improved magnetic properties were obtained in dual-alloy magnet. • This is due to the tuning of Ce distribution and the change in microstructure. • The magnetic hardening effect can be observed in dual-alloy magnet.

  4. Neutron scattering from α-Ce at epithermal neutron energies

    Indian Academy of Sciences (India)

    tures (~10 K), whereas CeSn3 is an α-Ce-like (valence fluctuation) system (TK ~ 35. meV) that remains paramagnetic down to low temperatures. Figure 1 shows the magnetic response from CeIn3 at 20 K [9]. A broad, well-defined crystal field exci- tation and a central quasielastic distribution are observed in this compound.

  5. Facile hydrothermal synthesis of CeO2 nanopebbles

    Indian Academy of Sciences (India)

    Administrator

    Abstract. 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.

  6. Metamagnetism in Ce (Ga, Al) 2

    Indian Academy of Sciences (India)

    Strongly Correlated Electron Systems Volume 58 Issue 5-6 May-June 2002 pp 769-771 ... 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 ...

  7. Thermodynamic stability studies of Ce-Sb compounds with Fe

    Science.gov (United States)

    Xie, Yi; Zhang, Jinsuo; Benson, Michael T.; Mariani, Robert D.

    2018-02-01

    Lanthanide fission products can migrate to the fuel periphery and react with cladding, causing fuel-cladding chemical interaction (FCCI). Adding a fuel additive dopant, such as Sb, can bind lanthanide, such as Ce, into metallic compounds and thus prevent migration. The present study focuses on the thermodynamic stability of Ce-Sb compounds when in contact with the major cladding constituent Fe by conducting diffusion couple tests. Ce-Sb compounds have shown high thermodynamic stability as they did not react with Fe. When Fe-Sb compounds contacted with Ce, Sb was separated out of Fe-Sb compounds and formed the more stable Ce-Sb compounds.

  8. Itinerant f-electron behavior in Ce and U compounds

    International Nuclear Information System (INIS)

    Crabtree, G.W.

    1985-04-01

    The experimentally observed Fermi surface properties in URh 3 , UIr 3 , UGe 3 , CeSn 3 , CeB 6 , U 3 As 4 , U 3 P 4 , and CeSb are reviewed. For the compounds with no magnetic order, band structure models of the Fermi surface geometry are confirmed and f-ligand hybridization is found to be dominant. For CeB 6 , U 3 As 4 , and U 3 P 4 the experiments show that both local moments and f hybridization are important. In CeSb new data can be explained by a purely local model with no f-hybridization

  9. Spin reorientation and Ce-Mn coupling in antiferromagnetic oxypnictide CeMnAsO

    Science.gov (United States)

    Vaknin, David; Zhang, Qiang; Peterson, Spencer; Dennis, Kevin; Tian, Wei

    2015-03-01

    Structure and complex magnetic properties of CeMnAsO, a parent compound of the ``1111''-type oxypnictides, have been investigated using neutron powder diffraction and magnetization measurements. Whereas there is no structural transition from the P4/nmm tetragonal phase below 420 K, CeMnAsO undergoes a C-type antiferromagnetic order with Mn2+ (S = 5 / 2) moments pointing along the c-axis below a relatively high Néel temperature of TN = 345 K. Below TSR = 35 K, two instantaneous transitions occur where the Mn moments reorient to the ab-plane preserving the C-type magnetic order, and Ce moments undergo long-range AFM ordering with moments in the ab-plane. Another transition to a noncollinear magnetic structure occurs below 7 K. We find that CeMnAsO primarily falls into the category of a local-moment antiferromagnetic insulator in which the nearest-neighbor interaction (J1) is dominant. The spin reorientation transition driven by the coupling between rare earth Ce and transition metal seems to be common to Mn, Fe and Cr ion,but not to Co and Ni ions in the iso-structural oxypnictides. Supported by the Office of Basic Energy Sciences, US-DOE, Number DE-AC02-07CH11358.

  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. Amperometric estimation of La3+ and Ce3+ with cupferron using d.m.e

    International Nuclear Information System (INIS)

    Pitre, K.S.; Lavale, S.C.

    1982-01-01

    Cupferron has been employed as a reagent for the amperometric titrations of La 3+ and Ce 3+ in very dilute solution using d.m.e. Hydrochloric acid (pH=2.75) has been used as supporting electrolyte. These titrations revealed cupferron to metal ratio of 1:1. Titrations are not hampered by the presence of a fairly large amount of Li + , Na + , K + , Mg 3+ , Zn 3+ , Al 3+ , Cl - , Br - , I - , NO 3 - , NO 2 - , CH 2 COO - and ClO 4 - ions. Furthermore, micro and ultramicro quantities of La 3+ and Ce 2+ have been successfully determined with an error of less than +- 0.70%. (author)

  12. Erosion-Corrosion Property of CeO2-Modified HVOF WC-Co Coating

    Science.gov (United States)

    Liu, Yan; Hang, Zongqiu; Chen, Hui; Ceng, Shengbo; Gou, Guoqing; Wang, Xiaomin; Tu, Mingjing; Wu, Xiangyang

    2016-04-01

    Rare-earth elements have been widely used in materials manufacturing to improve hardness and toughness. In this work, conventional, nanostructured, and CeO2-modified WC-12Co powders were sprayed using high-velocity oxygen flame spraying. The erosion-corrosion behavior and interaction of erosion and corrosion of the coatings in 3.5 wt.% NaCl solution were investigated. In situ observation was employed to analyze the failure mechanism. The results showed that the CeO2-modified WC-12Co coating possessed the best erosion-corrosion resistance, while the lowest corrosion resistance was exhibited by the conventional WC-12Co coating. The results also suggested that the erosion-corrosion mechanism in the three coatings was dominated by corrosion-accelerated erosion. However, the extent of acceleration of erosion by corrosion differed.

  13. Tectônica rúptil e sismicidade na área de inundação do açude do Castamhão (CE): implicações para o risco sísmico

    OpenAIRE

    Camarão Júnior, Luciano Formiga

    2001-01-01

    O presente estudo descreve os aspectos deformacionais frágeis e a sismicidade na região que será inundada pelo reservatório do Açude do Castanhão, porção leste do estado do Ceará. O lago artificial terá a capacidade para armazenar em torno de 6,7 bilhões de m3 de água. Também é planejada a instalação de uma usina hidroelétrica de pequeno porte. Cinco principais unidades litoestratigráficas foram identificadas na região: complexo gnáissico-migmatítico, seqüência metavulcanosedimentar, grani...

  14. Percepção Socioambiental dos Moradores sobre a Disposição Inadequada de Resíduos da Construção Civil (RCC de um Bairro em Expansão na cidade de Sobral/CE

    Directory of Open Access Journals (Sweden)

    Rennan Liberato Rodrigues

    2017-12-01

    Full Text Available Diante do cenário de crise ambiental vivenciado pela sociedade, uma das problemáticas mais preocupantes é a questão dos resíduos sólidos e, dentre esses, os que ocupam maior volume são os provenientes da indústria da construção civil. O presente trabalho apresenta um estudo sobre a percepção socioambiental dos moradores de um bairro em processo de expansão da cidade de Sobral/CE acerca da questão de resíduos sólidos. Tal estudo foi realizado por meio da aplicação de um questionário a fim de mensurar a consciência da população quanto à problemática. Concluiu-se que o bairro e os construtores carecem de programas de educação ambiental bem como de uma fiscalização mais eficiente.

  15. Spin reorientation and Ce-Mn coupling in antiferromagnetic oxypnictide CeMnAsO

    OpenAIRE

    Zhang, Qiang; Tian, Wei; Peterson, Spencer G.; Dennis, Kevin W.; Vaknin, David

    2014-01-01

    Structure and magnetic properties of high-quality polycrystlline CeMnAsO, a parent compound of the "1111"-type oxypnictides, have been investigated using neutron powder diffraction and magnetization measurements. We find that CeMnAsO undergoes a C-type antiferromagnetic order with Mn$^{2+}$ ($S=5/2$) moments pointing along the \\textit{c}-axis below a relatively high N\\'{e}el temperature of $T_{\\rm N} = 345$ K. Below $T_{\\rm SR} = 35$ K, two instantaneous transitions occur where the Mn moments...

  16. Neutron emission following muon capture in Ce-142, Ce-140, Ba-138, and Sn-120.

    Science.gov (United States)

    Lucas, G. R., Jr.; Martin, P.; Welsh, R. E.; Jenkins, D. A.; Powers, R. J.; Kunselman, A. R.; Miller, G. H.

    1973-01-01

    Branching ratios to excited nuclear states formed after muon capture have been measured with Ge(Li) detectors. The delayed gamma rays were observed in studies of muonic Ce-142, Ce-140, Ba-138, and Sn-120, using separated isotopes. The resulting isotopes formed indicate at least a 60% probability of neutron emission upon muon capture, with the most likely product resulting from single-neutron emission. No evidence for delayed proton emission with a probability higher than 2% was found. Using our more precise energies for the observed nuclear transitions, we present revised energy levels schemes for La-141, La-139, Cs-137, and In-119.

  17. Transient analysis capabilities at ABB-CE

    International Nuclear Information System (INIS)

    Kling, C.L.

    1992-01-01

    The transient capabilities at ABB-Combustion Engineering (ABB-CE) Nuclear Power are a function of the computer hardware and related network used, the computer software that has evolved over the years, and the commercial technical exchange agreements with other related organizations and customers. ABB-CEA is changing from a mainframe/personal computer network to a distributed workstation/personal computer local area network. The paper discusses computer hardware, mainframe computing, personal computers, mainframe/personal computer networks, workstations, transient analysis computer software, design/operation transient analysis codes, safety (licensed) analysis codes, cooperation with ABB-Atom, and customer support

  18. Synthesis and characterization of Ce doped MFI zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Kalita, Banani [Department of Chemistry, Gauhati University, Guwahati, Assam 781014 (India); Talukdar, Anup K., E-mail: anup_t@sify.com [Department of Chemistry, Gauhati University, Guwahati, Assam 781014 (India)

    2012-04-16

    Highlights: Black-Right-Pointing-Pointer Cerium was incorporated into the tetrahedral position of MFI zeolite structure. Black-Right-Pointing-Pointer Unit cell volume increases with an increase of Ce content in the framework of MFI. Black-Right-Pointing-Pointer A band at 310 nm in the UV-vis spectra indicates Ce incorporation in MFI structure. Black-Right-Pointing-Pointer The mass loss (%) in the region 373-423 K decreases with increase of Ce in MFI. - Abstract: Ce doped MFI (mobil five) zeolites with different Si to (Ce + Al) and different Ce to Al ratios were synthesized by a hydrothermal synthesis method. All the samples were characterized by different techniques such as X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), UV-vis diffuse reflectance spectroscopy (DRS) and scanning electron microscopy (SEM). The results showed that almost pure MFI phase was obtained in all cases with incorporation of cerium metal into the framework. The increase in unit cell parameters observed with an increase in Ce content is indicative of incorporation of Ce into the framework structure of microporous material MFI. Corroboration of the framework incorporation of Ce into the MFI zeolite structure was also obtained from the UV-vis DRS spectra by the presence of an absorption band at 280 nm. TGA and SEM of the samples provide complementary evidence for Ce incorporation into the framework MFI structure.

  19. Oxidation of Ce(III) in Foam Decontaminant by Ozone

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Chong Hun; Yoon, I. H.; Choi, W. K.; Moon, J. K.; Yang, H. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, J. S. [Gachon University, Seongnam (Korea, Republic of)

    2016-10-15

    A nanoparticle-based foam decontaminant is composed of a surfactant and nanoparticles for the generation and maintenance of foam, and a chemical decontamination agent made of Ce(IV) dissolved in nitric acid. Ce(IV) will be reduced to Ce(III) through the decontamination process. Oxidizing cerium(III) can be reused as a decontamination agent, Ce(IV). Oxidation treatment technology by ozone uses its strong oxidizing power. It can be regarded as an environmentally friendly process, because ozone cannot be stored and transported like other industrial gases (because it quickly decays into diatomic oxygen) and must therefore be produced on site, and used ozone can decompose immediately. The ozonation treatment of Ce(III) in foam decontaminant containing a surfactant is necessary for the effective regeneration of Ce(III). Thus, the present study was undertaken to determine the optimal conditions for ozonation treatment in the regeneration of Ce(III) into Ce(IV) in the nanoparticle-based foam decontaminant containing surfactant. This study was undertaken to determine the optimal conditions for ozonation treatment in the regeneration of Ce(III) to Ce(IV) in nanoparticle-based foam decontaminant containing a TBS surfactant. The oxidation conversion rate of Ce(III) was increased with an increase in the flow rate of the gas mixture and ozone injection amount. The oxidation time required for the 100% oxidation conversion of Ce(III) to Ce(IV) at a specific ozone injection amount can be predicted from these experimental data.

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

    International Nuclear Information System (INIS)

    Kim, Si Hyung; Kim, Gha-Young; Lee, Seung-jai; Kim, Taek-Jin; Paek, Seungwoo; Ahn, Do-Hee

    2015-01-01

    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

  1. Public Data at CeSAM

    Science.gov (United States)

    Moreau, C.; Le Brun, V.; Agneray, F.; Gimenez, S.; Roehlly, Y.

    2014-05-01

    Modern large observational programs produce important amounts of data from various origins, and need high level data-quality control, fast data access via easy-to-use graphic interfaces, as well as possibility to cross-correlate informations coming from different observations. The Centre de donneS Astrophysique de Marseille (CeSAM) has for mission to provide support to the teams in charge of the observational programs (specifications, software development and infrastructures), to produce and give the final data by proposing tools increasing their scientific value. We present here the various datasets hosted by the CeSAM under the ANIS environment. Even if mainly oriented towards large spectro-photometric extragalactic samples, we host as well an exoplanet transit database, or resolved galaxy data. The main datasets are those from the VVDS final release (45000 spectra), the Herschel extragalactic surveys (HerMES, HRS, GOODS-Herschel, VNGS), the CFHTLS-WIDE photometric redshifts catalog (17 millions objects), or the HST-COSMOS information system, that allows request from any of the 6 and access to the corresponding values in the other catalogs.

  2.  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.

  3. Neutron scattering from α-Ce at epithermal neutron energies

    Indian Academy of Sciences (India)

    the constant-ω integration within an energy bandwidth of ±30 meV around. 170 meV [13]. The continuous curve through the data shows the Ce3+ mag- netic form factor. The doted line shows the calculated form factor for an itinerant 4f electron band for α-Ce [14]. et al [14] calculated within the itinerant 4f band model for Ce.

  4. CeO2-ZrO2 ceramic compounds

    International Nuclear Information System (INIS)

    Melo, F.C.L.; Cairo, C.A.C.; Devezas, T.C.; Nono, M.C.A.

    1988-01-01

    In order to study the mechanical properties of tetragonal polycrystal zirconia stabilized with ceria various powder compositions with different CeO 2 content were made. Modulus of rupture for those compounds was measured. Tetragonal retained phase was determined for samples of CeO 2 -ZrO 2 ceramics with and without superficial mechanical treatment. The experimental results allowed us to evaluate the effects of CeO 2 content and sintering temperature in the mechanical properties and tetragonal transformed phase (t→ m) in ceramics of CeO 2 -ZrO 2 systems. (author) [pt

  5. High-Resolution Resonance Photoemission Study of CeNi

    International Nuclear Information System (INIS)

    Sekiyama, A.; Kadono, K.; Iwasaki, T.; Imada, S.; Kasai, S.; Suga, S.; Araki, S.; Onuki, Y.

    2003-01-01

    We have performed the high-resolution Ce 3d - 4f resonance photoemission study of a considerably hybridized CeNi with the Kondo temperature of ∼ 150 K. The tail of the Kondo-resonance peak is predominantly observed in the bulk Ce 4f photoemission spectra, where its spin-orbit partner is suppressed compared with the so far reported surface-sensitive Ce 4d-4f resonance spectrum. Our results show that the bulk 4f electronic states are essentially understood by the single impurity Anderson model. (author)

  6. 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.

  7. Parvenir à une réelle égalité entre les sexes en ce qui concerne la ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    3 nov. 2016 ... Photo : Dominic Chavez / Banque Mondiale. Le monde n'a jamais compté autant de jeunes (de 10 à 24 ans) ayant atteint l'âge de la reproduction qu'aujourd'hui. Malheureusement, la réalité sociale, économique et environnementale place ce 1,8 milliard d'adolescents parmi les personnes les plus ...

  8. Magnetic and structural properties of NaLnMnWO6 and NaLnMgWO6 perovskites

    International Nuclear Information System (INIS)

    King, Graham; Wayman, Lora M.; Woodward, Patrick M.

    2009-01-01

    We have prepared 14 new AA'BB'O 6 perovskites which possess a rock salt ordering of the B-site cations and a layered ordering of the A-site cations. The compositions obtained are NaLnMnWO 6 (Ln=Ce, Pr, Sm, Gd, Dy, and Ho) and NaLnMgWO 6 (Ln=Ce, Pr, Sm, Eu, Gd, Tb, Dy, and Ho). The samples were structurally characterized by powder X-ray diffraction which has revealed metrically tetragonal lattice parameters for compositions with Ln=Ce, Pr and monoclinic symmetry for compositions with smaller lanthanides. Magnetic susceptibility vs. temperature measurements have found that all six NaLnMnWO 6 compounds undergo antiferromagnetic ordering at temperatures between 10 and 13 K. Several compounds show signs of a second magnetic phase transition. One sample, NaPrMnWO 6 , appears to pass through at least three magnetic phase transitions within a narrow temperature range. All eight NaLnMgWO 6 compounds remain paramagnetic down to 2 K revealing that the ordering of the Ln 3+ cations in the NaLnMnWO 6 compounds is induced by the ordering of the Mn 2+ sub-lattice. - Graphical abstract: Evidence for multiple magnetic phase transitions in the A and B-site ordered perovskite NaPrMnWO 6 .

  9. Study of the crystal field in CeF3 and CeF3:Pr3+

    Directory of Open Access Journals (Sweden)

    Shafikov F.F., Savinkov A.V., Tagirov M.S.

    2016-12-01

    Full Text Available The crystal field analysis based on calculations in the framework of the semi phenomenological exchange charge model was carried out. The set of crystal field parameters for Ce3+ and Pr3+ ions in the matrix CeF3 related to the crystallographic system of coordinates has been obtained and used to reproduce satisfactory the crystal field energies of Ce3+ and Pr3+ ions.

  10. 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

  11. Optical properties of γ- and α-Ce by spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Joo Yull, Rhee.

    1992-01-01

    A rotating analyzer type ellipsometer with an ultra high vacuum sample chamber was built. The dielectric functions of γ- and α-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. γ- and α-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 x 10 -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 eff /N 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 eff /NA but the increased 4f-sd valence band hybridization exactly compensates the reduced oscillator strength. Therefore the net effects of the γ→α isostructural phase transition are an increase of optical conductivity and constancy of N eff /N A

  12. High Pressure Study of Electrical Resistivity of CeB6 to 136 GPa

    Science.gov (United States)

    Forouzani, Neda; Lim, Jinhyuk; Schilling, James; Fabbris, Gilberto; Fisk, Zachary

    2014-03-01

    Since the 1960's the dense Kondo compound cerium hexaboride (CeB6) has attracted a great deal of interest. To investigate whether this material might evolve into a topological insulator under sufficient pressure, we have carried out four-point electrical resistivity measurements on CeB6 over the temperature range 1.3 K to 295 K in a diamond anvil cell to 136 GPa. Although a transition into an insulating phase is not observed, the evolution of the initial dense Kondo state under such extreme pressures is of considerable interest. As reported in earlier studies to 13 GPa, the temperature of the resistivity maximum near 3 K initially increases with pressure. We observe that between 33 and 53 GPa the resistivity maximum disappears and by 83 GPa CeB6 appears to have settled into a Fermi liquid state. The marked changes observed under pressure suggest that a change in valence and/or a structural transition may have occurred. Synchrotron x-ray diffraction measurements are being carried out to investigate possible changes in crystal structure under extreme pressures. Work at Washington Univ. supported by NSF DMR-1104742 and Carnegie/DOE/NNSA DE-FC52-08NA28554.

  13. 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

  14. 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.

  15. Dopant concentration dependence of radiation-induced positive hysteresis of Ce:GSO and Ce:GSOZ

    International Nuclear Information System (INIS)

    Yanagida, Takayuki; Fujimoto, Yutaka; Watanabe, Kenichi

    2014-01-01

    Positive hysteresis and radiation tolerance to high-dose radiation exposure were investigated for Ce 0.5, 1, and 1.5%-doped Gd 2 SiO 5 (GSO) and for Zr co-doped GSO with the same Ce concentrations (GSOZ). When they were irradiated by 200–800 Gy 60 Co in 200 Gy steps, all Ce-doped GSO samples exhibited light yield enhancement (positive hysteresis). On the other hand, the light yield of GSOZ decreased greatly. Ce 0.5%-doped GSO showed the highest positive hysteresis, with ∼20% light yield enhancement. When the Ce concentration was increased, the positive hysteresis became weaker. - Highlights: • Positive hysteresis Ce 0.5, 1, and 1.5% doped GSO and GSOZ are studied. • Ce 0.5, 1, and 1.5% doped GSO show the positive hysteresis by 2–8 M rad 60 Co irradiation. • Ce 0.5, 1, and 1.5% doped GSOZ do not show the positive hysteresis. • By Zn co-doping, radiation tolerance of GSO becomes weaker. • By dense Ce doping, radiation tolerance of GSO and GSOZ are improved

  16. Traducerea: între ce se poate traduce și ce trebuie tradus

    Directory of Open Access Journals (Sweden)

    Magda Jeanrenaud

    2016-02-01

    Full Text Available Pornind de la o tulburătoare interpretare a lui Jacques Derrida, studiul de față își propune să investigheze și încearcă să explice blocajul ce intervine în versiunile englezești, franceze și românești (semnate de Antoine Berman, Alexis Nouss, Steven Rendall, Catrinel Pleșu etc. ale celebrului text al lui Walter Benjamin, Die Aufgabe des Übersetzers, atunci cînd traducătorii transpun în cele trei limbi țintă cele două citate cuprinse în acesta: un citat din Mallarmé, lăsat netradus de Benjamin însuși, și un altul, din Pannwitz. Într-un fel sau altul, ambele citate au o formă discursivă ce lasă să se întrevadă o sintaxă ce se abate deliberat de la normă, ca și cum ar fi deja niște „traduceri”. Analiza mai pune în evidență și comportamentul (cumva o dominantă a psihologiei traducătorilor? celor ce au transpus textul benjaminian, comportament marcat de obsesia lizibilității văzută ca o trăsătură congenitală a oricărei traduceri, chiar și atunci cînd textul original nu tinde spre aceasta. De unde și dilema, dureroasă, legată de spinoasa chestiune a intenționalității textului (nu doar de tradus...

  17. Comparison of root canal preparation using RaCe and ProTaper rotary Ni-Ti instruments.

    Science.gov (United States)

    Paqué, F; Musch, U; Hülsmann, M

    2005-01-01

    To compare various parameters of root canal preparation using RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium (Ni-Ti) instruments. Fifty extracted mandibular molars with mesial root canal curvatures between 20 degrees and 40 degrees were embedded in a muffle system. All root canals were prepared to size 30 using RaCe or ProTaper rotary instruments in low-torque motors with torque control and constant speed of 300 r.p.m. (ProTaper with ATR Tecnika, Advanced Technology Research, Pistoia, Italy; RaCe with EndoStepper, S.E.T., Olching, Germany). In both groups irrigation was performed with 2 mL NaOCl (3%) after each instrument size. Calcinase-Slide (lege artis, Dettenhausen, Germany) was used as a chelating agent with each instrument. The following parameters were evaluated: straightening of curved root canals, postoperative root canal cross-sections, safety issues and working time. Cleanliness of the root canal walls was investigated under the SEM using 5-score indices for debris and smear layer. Statistical analysis was performed using the following tests: Wilcoxon's test for straightening and working time was used (P < 0.05); Fisher's exact test for comparison of cross-sections and root canal cleanliness (P < 0.05). Both Ni-Ti systems maintained curvature well; the mean degree of straightening was less than 1 degrees for both systems. Following preparation with RaCe, 49% of the root canals had a round or oval diameter and 50% an irregular diameter, ProTaper preparations resulted in a round or oval diameter in 50% of the cases. For debris, RaCe and ProTaper achieved 47 and 49% scores of 1 and 2, respectively; there was no significant difference. For smear layer, RaCe and ProTaper achieved 51 and 33% scores 1 and 2, respectively; no statistically significant differences were apparent for the coronal and middle sections of the root canals, but RaCe performed significantly better in the

  18. Projected shell model study of neutron- deficient 122Ce

    Indian Academy of Sciences (India)

    Recently, Smith et al [1] have communicated the existence of neutron-deficient 122Ce and its excited states have been reported up to spin 14¯h. The band has been as- signed to 122Ce by detecting γ-rays in coincidence with evaporated charged particles and neutrons. The nucleus is believed to have large ground state ...

  19. Facile hydrothermal synthesis of CeO2 nanopebbles

    Indian Academy of Sciences (India)

    Administrator

    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 .... state.26 In our case, the valence of cerium ions will be mainly 4+ state, because the estimated particle size of.

  20. Three-Dimensional Structure of CeO2 Nanocrystals

    DEFF Research Database (Denmark)

    Tan, Joyce Pei Ying; Tan, Hui Ru; Boothroyd, Chris

    2011-01-01

    truncated octahedral CeO2 particles through a lattice matched interface generated irregular compressed truncated octahedral CeO2 nanoparticles. The formation of this irregular shape is attributed to the lower surface diffusion and slow incorporation of atoms on surfaces by step attachment of the fused...

  1. Ce que nous faisons | CRDI - Centre de recherches pour le ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Le CRDI appuie des travaux de recherche dans les pays en voie de développement en vue de produire un changement réel et durable. Ce savoir peut servir d'outil pour résoudre des problèmes mondiaux urgents. Nous partageons ce savoir avec les autres en :

  2. Low temperature synthesis of fluorite-type Ce-based oxides of ...

    Indian Academy of Sciences (India)

    M MALATHI

    type) Ce-based oxides of compositions Ln2Ce2O7 (Ln = Pr, Nd and Eu). F-type oxides can be considered as multi-functional materials due to the deficiency of anions. Pr2Ce2O7 (PCO), Nd2Ce2O7 (NCO) and Eu2Ce2O7 (ECO) were prepared ...

  3. 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.

  4. Multimedia Experience on Web-Connected CE Devices

    Science.gov (United States)

    Tretter, Dan; Liu, Jerry; Zhang, Xuemei; Gao, Yuli; Atkins, Brian; Chao, Hui; Xiao, Jun; Wu, Peng; Lin, Qian

    Consumer electronics (CE) are changing from stand-alone single-function devices to products with increasing connectivity, convergence of functionality, and a focus on customer experience. We discuss the features that characterize the new generation of CE and illustrate this new paradigm through an examination of how web services can be integrated with CE products to deliver an improved user experience. In particular, we focus on one aspect of the CE segment, digital photography. We introduce AutoPhotobook, an automatic photobook creation service and provide a detailed look at how it addresses the complexity of photobook authoring through a portfolio of automatic photo analysis and composition technologies. We then show how this collection of technologies is integrated into a larger ecosystem with other web services and web-connected CE devices to deliver an enhanced user experience.

  5. Photodynamic Processes in Fluoride Crystals Doped with Ce3+

    Directory of Open Access Journals (Sweden)

    Pavlov V.V.

    2015-01-01

    Full Text Available Integrated studies of photoelectric phenomena and their associated photodynamic processes in LiCaAlF6, LiLuF4, LiYF4, LiY0,5Lu0,5F4, SrAlF5 crystals doped with Ce3+ ions have been carried out using the combination of the methods of optical and dielectric spectroscopy. The numerical values of the basic parameters of photodynamic processes and their spectral dependence in 240 – 310 nm spectral range are evaluated. It has been shown that the most probable process, which leads to the photoionization of Ce3+ ions in LiYxLu1-xF4:Ce3+ (x=0; 0,5; 1 and LiCaAlF6:Ce3+ crystals, is excited-state absorption to the states of mixed configurations of Ce3+ ions localized near/in the conduction band of crystal.

  6. 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.

  7. Sorption of Fe3+ , Co2+ , Ce3+ , Cs+ and Ba2+ in zeolite X

    International Nuclear Information System (INIS)

    Martinez M, V.

    1994-01-01

    The sorption behavior of Fe 3+ , Co 2+ , Ce 3+ , Cs + , and Ba 2+ in aqueous solutions, was studied in presence of zeolite X. Solutions of Fe(NO 3 ) 3 . 9 H 2 O, Co(NO 3 ) 2 . 6 H 2 O, Ce(NO 3 ) 3 . 6 H 2 O, Cs NO 3 and Ba(NO 3 ) 2 were labelled with the respectively radioactive isotopes Fe 59 , Co 60 , Cs 134 , Ba 139 and Ce 141 . 20 ml. of each solution was left in contact with 200 mg. of zeolite for different periods. Later the zeolites were separated by centrifugation from the aqueous solutions and the radioactivity of the aqueous phases was measured with a NaI(Tl) solid-state well detector coupled to a single-channel Picker analyzer or with a Gel hyper pure solid-state detector coupled to a 2048 channel pulse height analyzer. When Cs + in the aqueous solutions was left in contact with zeolite X it was found that it does not occupy all cationic sites in the zeolite due to the ionic radium effect. A similar behavior was found for the divalent ions. In all cases, when the pH was not controlled, the zeolite lost part of its crystallinity and when the divalent ions were exchanged again by Na + , the zeolite recovered completely its crystallinity. During the sorption, the ionic radius, and the charge are important parameters as well as the pH. When the pH of the solution was adjusted between 6.5 - 7.0 the crystallinity was maintained in some cases. For Fe 3+ the crystallinity after the ion exchange was 94 % and when the pH was not adjusted the crystallinity was completely lost. It was found as well that the zeolite X induces the formation of H 3 O + which competes with the cations for the sites in the zeolite. (Author)

  8. 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.

  9. Possible Frustration Effects on a New Antiferromagnetic Compound Ce6Pd13Zn4 with the Octahedral Ce Sublattice

    Science.gov (United States)

    Matsuoka, Eiichi; Oshima, Akihiro; Sugawara, Hitoshi; Sakurai, Takahiro; Ohta, Hitoshi

    2018-01-01

    Magnetization, specific heat, and electrical resistivity measurements have been performed on polycrystalline samples of a new cubic compound, Ce6Pd13Zn4. This compound exhibits metallic behavior and is classified as a Kondo-lattice system. The trivalent Ce ions are responsible for the antiferromagnetic transition at TN = 3.3 K and the phase transition at T'N = 1.3 K with the formation of superzone gaps. The increase in magnetic susceptibilities below TN and the considerably large value of the specific heat divided by temperature (1.25 J·Ce-mol-1·K-2) imply the existence of non-ordered Ce magnetic moments due to the geometrical frustration on the octahedral Ce sublattice.

  10. Tetragonal zirconia ceramics in Zr O2-Ce O2 system (Ce-TZP): preparation, characterization and mechanical properties

    International Nuclear Information System (INIS)

    Andrade Nono, M.C. de.

    1992-01-01

    This paper describes and discusses the results achieved in a study about Ce-TZP ceramics prepared from conventional powder mixtures of Zr O 2 and Ce O 2 (with composition in the range of 8 to 16 mol% Ce O 2 ). Physical and chemical characteristics were related with the powder compaction behavior and with the sintering state. The sintered ceramics showed a level of high porosity (≅ 4%), mainly due to the fairly adequate powder characteristics and compaction. The crystalline phases were analysed from X-rays diffraction data and showed that these ceramics can present tetragonal-to-monoclinic stress induced transformation. The bending strength, fracture toughness and Vickers hardness results were influenced by Ce O 2 content microstructure and sintering temperature. These Ce-TZP ceramics showed mechanical strength results comparable to those published in the international literature. (author)

  11. 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

  12. SYNTHESIS, FTIR SPECTROSCOPY, AND SURFACE MICROMORPHOLOGY OF Се(III AND Ce(IV-CONTAINING HETEROPOLY TUNGSTATES WITH PEACOCK–WEAKLEY STRUCTURE OF ANION

    Directory of Open Access Journals (Sweden)

    O. Yu. Mariichak

    2017-09-01

    size of Na6H2[CeIV(W5O182]·30H2O is within the range of 200–400nm, while the grain size of Na9[СеIII(W5O182]·28H2О makes up to 2.5μm. Homogeneity of the obtained samples was confirmed by the uniform contrast of the surface mode of backscattered electrons. On the micrographs of salts powder in characteristic X-ray emission there are no regions with different surface morphology, and there is an even distribution of Ce, Na, W, and O, without segregation and eliquation. These clearly point to the formation of single phase samples.

  13. Catalytic Hydrothermal Liquefaction of Food Waste Using CeZrOx

    Directory of Open Access Journals (Sweden)

    Alex R. Maag

    2018-03-01

    Full Text Available Approximately 15 million dry tons of food waste is produced annually in the United States (USA, and 92% of this waste is disposed of in landfills where it decomposes to produce greenhouse gases and water pollution. Hydrothermal liquefaction (HTL is an attractive technology capable of converting a broad range of organic compounds, especially those with substantial water content, into energy products. The HTL process produces a bio-oil precursor that can be further upgraded to transportation fuels and an aqueous phase containing water-soluble organic impurities. Converting small oxygenated compounds that partition into the water phase into larger, hydrophobic compounds can reduce aqueous phase remediation costs and improve energy yields. HTL was investigated at 300 °C and a reaction time of 1 h for conversion of an institutional food waste to bio-oil, using either homogeneous Na2CO3 or heterogeneous CeZrOx to promote in situ conversion of water-soluble organic compounds into less oxygenated, oil-soluble products. Results with food waste indicate that CeZrOx improves both bio-oil higher heating value (HHV and energy recovery when compared both to non-catalytic and Na2CO3-catalyzed HTL. The aqueous phase obtained using CeZrOx as an HTL catalyst contained approximately half the total organic carbon compared to that obtained using Na2CO3—suggesting reduced water treatment costs using the heterogeneous catalyst. Experiments with model compounds indicated that the primary mechanism of action was condensation of aldehydes, a reaction which simultaneously increases molecular weight and oxygen-to-carbon ratio—consistent with the improvements in bio-oil yield and HHV observed with institutional food waste. The catalyst was stable under hydrothermal conditions (≥16 h at 300 °C and could be reused at least three times for conversion of model aldehydes to water insoluble products. Energy and economic analysis suggested favorable performance for the

  14. 2D NiFe/CeO2 Basic-Site-Enhanced Catalyst via in-Situ Topotactic Reduction for Selectively Catalyzing the H2 Generation from N2H4·H2O.

    Science.gov (United States)

    Wu, Dandan; Wen, Ming; Gu, Chen; Wu, Qingsheng

    2017-05-17

    An economical catalyst with excellent selectivity and high activity is eagerly desirable for H 2 generation from the decomposition of N 2 H 4 ·H 2 O. Here, a bifunctional two-dimensional NiFe/CeO 2 nanocatalyst with NiFe nanoparticles (∼5 nm) uniformly anchored on CeO 2 nanosheets supports has been successfully synthesized through a dynamic controlling coprecipitation process followed by in-situ topotactic reduction. Even without NaOH as catalyst promoter, as-designed Ni 0.6 Fe 0.4 /CeO 2 nanocatalyst can show high activity for selectively catalyzing H 2 generation (reaction rate (mol N2H4 mol -1 NiFe h -1 ): 5.73 h -1 ). As ceria is easily reducible from CeO 2 to CeO 2-x , the surface of CeO 2 could supply an extremely large amount of Ce 3+ , and the high-density electrons of Ce 3+ can work as Lewis base to facilitate the absorption of N 2 H 4 , which can weaken the N-H bond and promote NiFe active centers to break the N-H bond preferentially, resulting in the high catalytic selectivity (over 99%) and activity for the H 2 generation from N 2 H 4 ·H 2 O.

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

    International Nuclear Information System (INIS)

    Dai, Jiahong; Jiang, Bin; Li, Xin; Yang, Qingshan; Dong, Hanwu; Xia, Xiangsheng; Pan, Fusheng

    2015-01-01

    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 4 Ce, Al 11 Ce 3 , Al 3 Ce, Al 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 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 4 Ce, Al 11 Ce 3 , Al 3 Ce, Al 2 Ce and AlCe were formed via the reaction of Al and Ce. The formation of Al 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

  16. A new adsorbent of a Ce ion-implanted metal-organic framework (MIL-96) with high-efficiency Ce utilization for removing fluoride from water.

    Science.gov (United States)

    Yang, Xuan; Deng, Shuangshuang; Peng, Fumin; Luo, Tao

    2017-02-14

    A novel Ce(iii) ion-implanted aluminum-trimesic metal-organic framework (Ce-MIL-96) was synthesized for the first time via alcohol-solvent incipient wetness impregnation. Compared to previously reported Ce-contained adsorbents, the fluoride adsorption performance of the new ion-implanted metal-organic framework demonstrated much higher adsorption capacity and more efficient regeneration of Ce. In a wide pH range of 3 to 10, Ce-MIL-96 maintained constant adsorption performance for fluoride, and the residual Ce and Al in the treated solution were below the safe limits in drinking water. The maximum adsorption capacity of Ce-MIL-96 was 38.65 mg g -1 at 298 K. Excluding the contribution of MIL-96, the maximum adsorption capacity of Ce ions was 269.75 mg g -1 , which demonstrated that the service efficiency of cerium in Ce-MIL-96 is about 6 times that in Ce 2 O 3 , nearly 10 times that in Ce-mZrp, and double that in Mn-Ce oxides. There was no significant influence on fluoride removal by Ce-MIL-96 due to the presence of chloride, nitrate, sulfate, bicarbonate or phosphate. Moreover, the adsorption capacity of Ce-MIL-96 remained at more than 70% after nine cycles of adsorption-desorption. Due to this excellent adsorption performance and its regeneration properties, Ce-MIL-96 is a promising adsorbent for the removal of fluoride from groundwater.

  17. 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

  18. Negative Ce anomalies in Mn oxides: The role of Ce4+ mobility during water-mineral interaction

    Science.gov (United States)

    Loges, Anselm; Wagner, Thomas; Barth, Matthias; Bau, Michael; Göb, Susanne; Markl, Gregor

    2012-06-01

    We present one of the very rare natural examples of extremely negative Ce anomalies (up to 4 orders of magnitude) in manganese oxides, caused by higher mobility of Ce4+ compared to REE3+ in an aquatic environment. The young secondary Mn oxides formed together with fluorites and goethites during water-mineral interaction in a hydrothermal fluorite vein. Our findings are in contrast to the oxidative scavenging of Ce, which is commonly observed in Mn oxides. Comparison of REE patterns from modern mine waters with primary and secondary minerals demonstrates that this cannot be solely explained as a source-related feature or by immobilization of Ce, but must at least partially be the result of preferential mobilization of Ce4+ compared to REE3+. We propose that this very unusual behavior is due to strong complexation of Ce4+, most likely by siderophores or similar organic molecules, based on published complex formation constants. The presence of dissolved organic carbon (DOC) even in water samples outflowing at the deepest mine level lends support to this model. Recent experimental studies have also demonstrated that negative Ce anomalies develop in biogenic Mn oxides, but this effect has not yet been reported from a natural environment. Our findings emphasize the relevance of experimental results for natural systems and have considerable implications for the assessment of the mobility of tetravalent actinide elements (especially Pu4+) in earth surface environments or potential high-level permanent repositories.

  19. CE-MS fingerprinting of Laurencia complex algae (Rhodophyta).

    Science.gov (United States)

    Machín-Sánchez, María; Asensio-Ramos, María; Hernández-Borges, Javier; Gil-Rodríguez, María Candelaria

    2014-03-01

    The use of CE-ESI-MS has been considered as a new chemical strategy for the possible discernment of genera and species of the Laurencia complex. After the selection of the CE-MS and the extraction conditions, a total of 28 specimens of the complex, including different species of four genera (Laurencia, Laurenciella, Palisada, and Osmundea) collected from five intertidal locations on the Island of Tenerife (Canary Islands, Spain) were analyzed. CE-MS fingerprints revealed that CE-MS can be used as a useful tool for these studies in order to assess similarities and differences between them and that it constitutes an important starting point for further studies in the field. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Performance evaluation of LaBr3: Ce scintillator

    International Nuclear Information System (INIS)

    Xie Ming; Lin Li; Liu Shihao; Xiao Peng; Xie Qingguo

    2012-01-01

    The cerium doped lanthanum bromide crystal (LaBr 3 : Ce) is a new kind of scintillator with many advantages such as good energy resolution, high light output, short decay time, good proportionality response. These properties make the LaBr 3 : Ce attractive substantial interest to use in the radiation detection. The energy resolution were investigated with Φ25 × 25 mm LaBr 3 : Ce coupled to a Hamamatsu R8900 photomultiplier tube. Energy resolution of 3.6% (FWHM) have been achieved for 511 keV photons ( 18 F source) at room temperature. Decay time constant of 20 ns have been acquired with a Hamamatsu fast-time-response R9800 photomultiplier tube. The results approve the excellent characterizations of LaBr 3 : Ce and imply its enormous potentiality in the radiation detectors of gamma-ray spectroscopy and PET. (authors)

  1. Temperature-independent photoluminescence response in ZnO:Ce ...

    Indian Academy of Sciences (India)

    2017-12-06

    Ce3+ nanophosphors prepared by combustion method and solid-state reaction method is presented in this study. The powder XRD exhibits hexagonal wurtzite phase and crystallite size falls in the nanometre range. The optical ...

  2. 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

  3. Hydrogen-bridge Si(μ-H)3CeH and inserted H3SiCeH molecules: Matrix infrared spectra and DFT calculations for reaction products of silane with Ce atoms

    Science.gov (United States)

    Xu, Bing; Shi, Peipei; Huang, Tengfei; Wang, Xuefeng

    2017-10-01

    Reactions of laser-ablated cerium atoms with silane were investigated by matrix isolation infrared spectroscopy and theoretical calculations. The reaction products, Si(μ-H)3CeH, H3SiCeH, H2Si(μ-H)CeH and HSi(μ-H)2CeH were identified on the basis of the SiD4 isotopic substitutions and DFT frequency calculations. In the solid argon or krypton matrix, the inserted H3SiCeH molecule was observed as initial product on deposition, which rearranged to hydrogen bridge species Si(μ-H)3CeH on follow-up annealing through H2Si(μ-H)CeH and HSi(μ-H)2CeH species. The Sisbnd Hsbnd Ce hydrogen bridge was investigated by NBO and ELF analysis. Calculation suggested that in Si(μ-H)3CeH molecule Ce atom donated one electron to Si atom, resulting in electron-rich SiH3 subunit, which was confirmed by ESP and AIM analysis. The increased basicity of Sisbnd H bond facilitates the formation of hydrogen bridge bond between Si and Ce. For comparison only insertion H3CCeH structure was obtained from the reaction of Ce atoms with CH4.

  4. Seamless Ligation Cloning Extract (SLiCE) Cloning Method

    OpenAIRE

    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 D...

  5. Description and Application of the CE-SE Scheme

    Directory of Open Access Journals (Sweden)

    Martin KOSÍK

    2010-12-01

    Full Text Available The CE-SE scheme is new numerical methodology for conservation laws. It was developed by Dr.Chang of NASA Glenn Research Center and his collaborators. The 1D and 2D variant of CE-SE scheme for scalar convection and for Euler equations for incompressible flows is described. The CESE scheme is compared with classical schemes in 1D. The solution to inviscid incompressible flow in GAMM channel in 2D is presented.

  6. Dissolved cerium contributes to uptake of Ce in the presence of differently sized CeO2-nanoparticles by three crop plants.

    Science.gov (United States)

    Schwabe, Franziska; Tanner, Simon; Schulin, Rainer; Rotzetter, Aline; Stark, Wendelin; von Quadt, Albrecht; Nowack, Bernd

    2015-03-01

    We investigated the uptake of cerium (Ce) dioxide nanoparticles (NPs) by hydroponically grown wheat, pumpkin and sunflower plants. The presence of plant roots in nutrient solution led to a substantial increase in the dissolution of CeO2-NP compared to plant-free medium. Experiments with Zr/CeOx-NP revealed that Ce was not only taken up in the form of NPs, but simultaneously to a significant degree also as dissolved Ce(iii) ions, which then re-precipitated in the form of CeO2-NPs inside the leaves. The contribution of dissolved Ce uptake was particularly large for particles smaller than 10 nm due to their higher dissolution rate. Our data also indicate that the translocation of Ce resulting from NP-root-exposure is species dependent. When Ce was supplied as dissolved ions, sunflower had the highest capacity of Ce-ion accumulation inside the leaves, while there was no significant difference between pumpkin and wheat. We found no Ce translocation from roots into shoots when only NPs bigger than 20 nm were applied. This study highlights that plant root activity can have a significant impact on the dissolution of CeO2-NPs in soil solution and that uptake of dissolved Ce(iii) followed by re-precipitation needs to be considered as an important pathway in studies of CeO2-NP uptake by plants.

  7. The determination of the acoustical phonon dispersion branches of CePd3 by inelastic neutron diffraction

    International Nuclear Information System (INIS)

    Severing, A.

    1985-07-01

    The result of this thesis is, that the phonon dispersion of CePd 3 , measured by inelastic neutron scattering, does not show any phonon softening effects due to valence fluctuations as it is observed in the phonon dispersion spectra of TmSe, SmS under pressure and SMsub(.75)Ysub(.25)S in dependence of the temperature. Even at low temperature no softening effects could be detected in comparison to the room temperature data. However we see indications for the existence of intermediate valence induced electron-phonon couplings in the linewidth of the longitudinal acoustic phonon in -direction with reduced wavevector xi=0.2. This phonon seems to be broadened at 135 K. If this broadening is a real intermediate valence effect, this effects manifest themselves much weaker in CePd 3 than in the substances with NaCl-structure. The question whether such couplings realy exist can only be answered by further measurements. (orig.)

  8. CeO{sub 2} nanoparticles deposited on carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Guobin; Nomiyama, Ryoma; Sano, Hideaki; Uchiyama, Yasuo, E-mail: gbzheng@nagasaki-u.ac.jp [Department of Materials Science and Engineering, Nagasaki University, Bunkyo machi 1-14, Nagasaki, 852-8521 (Japan)

    2011-10-29

    Carbon nanotubes (CNTs) with average diameter of 14 nm were modified by oxidation in nitric acid and followed by treatment in sodium dodecyl sulfate (SDS). XPS analysis verified the introduction of carboxyl group and SDS molecules onto the CNT surface. The CeO{sub 2} coatings on CNTs were synthesized using two different processes; chemical precipitation method and solvothermal method. TEM observation showed that the coatings consisted of CeO{sub 2} nanoparticles with size of several nanometers. It is believed that in chemical precipitation method, the surface modification with carboxyl group and SDS provided nucleation sites of CeO{sub 2}, thus facilitating further growth and attachment of CeO{sub 2} nanoparticles. In solvothermal method, due to the interaction between graphene surface of CNTs and solvent pyridine, CeO{sub 2} particles could form on the pristine CNTs, and the surface modification decreased the nucleation sites of CeO{sub 2} and thus led to thinner or incomplete coating.

  9. 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.

  10. Optical and scintillation properties of Ce-doped LuLiF{sub 4} with different Ce concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Yanagida, Takayuki, E-mail: yanagida@lsse.kyutech.ac.jp [Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0196 (Japan); Fujimoto, Yutaka [Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0196 (Japan); Fukuda, Kentaro [Tokuyama Corporation, Shibuya 3-chome, Shibuya-ku, Tokyo 150-8383 Japan (Japan); Chani, Valery [Tohoku Univ., 2-1-1 Katahira, Sendai 980-8577 (Japan)

    2013-11-21

    The crystals of 0.1, 0.5, and 1 mol% Ce-doped LuLiF{sub 4} (Ce:LLF) grown by the micro-pulling down (μ-PD) method were examined for their optical and scintillation properties. Ce:LLF crystals had ∼80% transparency at wavelengths longer than 300 nm. In photoluminescence spectra, they demonstrated intense emission peaks at 310 and 330 nm with the quantum yield of 60–90%. Ce{sup 3+} 5d–4f emission peaks were also detected at similar wavelengths of 310 and 330 nm in the radioluminescence spectra obtained under X-ray excitation. According to pulse height spectra recorded under γ-ray irradiation, the absolute light yield of Ce 0.1, 0.5, and 1% were 3600±400, 3000±300, and 1700±200 ph/MeV, respectively. Decay time kinetics was also inspected using a pulse X-ray equipped streak camera system. The decay time components of Ce:LLF were ∼70 ns and ∼1 μs for all the samples.

  11. Optical and scintillation properties of Ce-doped LuLiF4 with different Ce concentrations

    International Nuclear Information System (INIS)

    Yanagida, Takayuki; Fujimoto, Yutaka; Fukuda, Kentaro; Chani, Valery

    2013-01-01

    The crystals of 0.1, 0.5, and 1 mol% Ce-doped LuLiF 4 (Ce:LLF) grown by the micro-pulling down (μ-PD) method were examined for their optical and scintillation properties. Ce:LLF crystals had ∼80% transparency at wavelengths longer than 300 nm. In photoluminescence spectra, they demonstrated intense emission peaks at 310 and 330 nm with the quantum yield of 60–90%. Ce 3+ 5d–4f emission peaks were also detected at similar wavelengths of 310 and 330 nm in the radioluminescence spectra obtained under X-ray excitation. According to pulse height spectra recorded under γ-ray irradiation, the absolute light yield of Ce 0.1, 0.5, and 1% were 3600±400, 3000±300, and 1700±200 ph/MeV, respectively. Decay time kinetics was also inspected using a pulse X-ray equipped streak camera system. The decay time components of Ce:LLF were ∼70 ns and ∼1 μs for all the samples

  12. Influence of Ce-H bonding on the physical properties of the hydrides CeCoSiH1.0 and CeCoGeH1.0

    International Nuclear Information System (INIS)

    Chevalier, B; Matar, S F; Menetrier, M; Marcos, J Sanchez; Fernandez, J Rodriguez

    2006-01-01

    The hydrides CeCoSiH 1.0 and CeCoGeH 1.0 which crystallize like the parent antiferromagnetic compounds CeCoSi and CeCoGe in the tetragonal CeFeSi-type structure, have been investigated by specific heat and thermoelectric power measurements and 1 H nuclear magnetic resonance (NMR). CeCoSiH 1.0 is an intermediate valence compound whereas CeCoGeH 1.0 can be considered as a nearly trivalent cerium compound. This behaviour is corroborated by the occurrence of a slight broadening of the 1 H NMR signal in the sequence CeCoSiH 1.0 → CeCoGeH 1.0 . The band structure calculations performed on these hydrides reveal the existence of strong bonding Ce-H interaction, found to be larger in CeCoSiH 1.0 than in CeCoGeH 1.0

  13. Effect of yttrium on electron–phonon coupling strength of 5d state of Ce3+ ion in LYSO:Ce crystals

    International Nuclear Information System (INIS)

    Ding, Dongzhou; Liu, Bo; Wu, Yuntao; Yang, Jianhua; Ren, Guohao; Chen, Junfeng

    2014-01-01

    This paper aims at an improved understanding of luminescence properties of (Lu 1−x Y x ) 2 SiO 5 :Ce (x=0 at%, 26 at%, 45 at%, 66 at% and 100 at%). Photoluminescence emission and excitation spectra as well as Raman spectra of (Lu 1−x Y x ) 2 SiO 5 :Ce were investigated as a function of yttrium (shortened as Y) content in it. Obtained Huang–Rhys factor S indicates that the coupling between Ce1 (7-oxygen-coordinated), Ce2 (6-oxygen-coordinated) and LYSO lattice is intermediate and strong, respectively. Besides, it was found that: with the increase of Y content, crystal field strength around Ce1 and Ce2 decreases, Stokes shift of Ce1 and Ce2 presents an increase trend, and S of Ce2 tends to decrease. These phenomena were explained by geometrical influence of Y 3+ /Lu 3+ on the crystal field splitting of the 5d levels of Ce 3+ and coupling strength. With the increase of Y content, the evolution of S and coupling energy ħω of Ce1 present a slight increase and decrease trend respectively, while S and coupling energy ħω of Ce2 present an obvious decrease and increase trend, respectively. - Highlights: • Crystal field strength around Ce1 decreases with increase of Y content in LYSO:Ce. • A diagram of Huang–Rhys factor S against Y content in LYSO:Ce was constructed. • A diagram of coupling energy ħω against Y content in LYSO:Ce was constructed. • A diagram of Stokes shift against Y content in LYSO:Ce was constructed

  14. Ce-doped nanoparticles of TiO2: Rutile-to-brookite phase transition and evolution of Ce local-structure studied with XRD and XANES

    International Nuclear Information System (INIS)

    Kityakarn, Sutasinee; Worayingyong, Attera; Suramitr, Anwaraporn; Smith, M.F.

    2013-01-01

    The crystal and electronic structural changes undergone by TiO 2 nanoparticles when Ce is introduced were studied using X-ray diffraction (XRD) and X-ray absorption near-edge spectroscopy (XANES). A small amount of Ce (less than 1% molar concentration) resulted in i/a significant reduction of the average size of the TiO 2 nanoparticles and ii/a phase transition in which brookite replaced rutile as the minority phase component (anatase was the majority phase component at all Ce concentrations studied up to 10% molar concentration). The Ce L3 edge XANES revealed changes in the local environment of Ce impurities. As Ce concentration was increased the fraction of Ce that have formal valence of +3 decreased and, for the remaining Ce with valence +4, the 4f orbitals became less-strongly hybridized with the p-orbitals of oxygen neighbors. The results have implications for photocatalytic and gas sensing properties of Ce-doped TiO 2 . - Highlights: ► Ce-doping: TiO 2 nanoparticles shrink and minority phase changes rutile-> brookite. ► XANES reveals phase change for arbitrarily small particles (while XRD fails). ► As Ce added: fraction of Ce +3 dopants falls, hybridization of Ce +4 with O weakens

  15. Investigating the capability of ToF-SIMS to determine the oxidation state of Ce

    Science.gov (United States)

    Seed Ahmed, H. A. A.; Swart, H. C.; Kroon, R. E.

    2018-04-01

    The capability of time of flight secondary ion mass spectrometry (ToF-SIMS) to determine the oxidation state of Ce ions doped in a phosphor was investigated. Two samples of SiO2:Ce (4 mol%) with known Ce3+/Ce4+ relative concentrations were subjected to ToF-SIMS measurements. The spectra were very similar and no significant differences in the relative peak intensities were observed that would readily allow one to distinguish Ce3+ from Ce4+. Although ToF-SIMS was therefore not useful to distinguish the charge state of Ce ions doped in this phosphor material, the idea in principle was also tested on two other samples, namely CeF3 and CeF4 These contain Ce as part of the host (i.e. much higher concentration) and are fluorides, which is significant because ToF-SIMS has previously been reported to be able to distinguish Eu2+ from Eu3+ in Eu doped Sr5(PO4)3F phosphor. The spectrum of CeF4 contained a small peak related to Ce4+ which was not observed in the CeF3 spectrum, yet the peak related to the Ce3+ ions was found to be much more intense in the spectrum of CeF4 than CeF3, showing that the ToF-SIMS signals cannot be directly interpreted as retaining the charge state of the ions in the original material. Nevertheless, the significant differences in the Ce-related peaks in the ToF-SIMS spectra from CeF3 and CeF4 show that the charge state of Ce may be distinguished. This study shows that while in principle ToF-SIMS may be used to distinguish the charge state of Ce ions, this depends on the sample and it would not be easy to interpret the spectra without a standard or reference.

  16. Photocatalytic activity of Ce-modified SBA-15 for the degradation of ...

    Indian Academy of Sciences (India)

    CeO2 or CeO2-based materials have also been found to be very important under environmental protection materials family. In particular, supported CeO2 and CeO2-based mixed oxides are effective catalysts for the ... made slurry in ethanol containing aluminum isopropoxide for 8 h at room temperature. The filtered ...

  17. Uljanow – człowiek bezdomny. Uwagi o książce Helen Rappaport

    Directory of Open Access Journals (Sweden)

    Piotr Kuligowski

    2016-06-01

    Full Text Available Helen Rapport w swojej książce Conspirator: Lenin in Exile proponowała nowe spojrzenie na emigracyjny okres życia Lenina, to jest na lata 1902–1917, jako na czas najistotniejszy w życiu rosyjskiego rewolucjonisty. Ten sposób ujęcia zagadnienia otwiera przestrzeń dla nowych interpretacji, ale także wiąże się z określonymi problemami. Rappaport udało się do pewnego stopnia „odbrązowić” Lenina i ukazać go jako postać, której cechy i światopogląd wówczas dopiero się kształtowały. Z drugiej jednak strony, książka zawiera sporo słabo ugruntowanych źródłowo, lecz „sensacyjnych” wątków, które w dużej mierze zapewniły jej rozgłos. Rappaport nie dała również przekonujących odpowiedzi na pytanie, w jaki sposób pobyt w różnych krajach Europy wpłynął na ewolucję światopoglądową Lenina, ograniczając się w tej sferze do referowania kolejnych prac rosyjskiego rewolucjonisty lub do prób przyjrzenia się im przez pryzmat jego cech psychologicznych.

  18. Návrh strategie pro vybudování ziskového víceúrovňového podnikání

    OpenAIRE

    Mokrý, Martin

    2010-01-01

    Předložená diplomová práce se zabývá tématem víceúrovňového marketingu jako oboru pro samostatné podnikání jednotlivce. Posuzuje pozitiva a negativa této metody podnikání a rozdílnost od podvodných modelů. Diplomová práce se zaměřuje zejména na navržení konkrétních postupů vedoucích k vybudování stabilního příjmu v tomto odvětví a k tomu využívá současné poznatky o víceúrovňovém marketingu, základní metody určování kompetencí, kompetenčních modelů a koučování. This diploma thesis deals wit...

  19. Hydrogen Production from Methanol Steam Reforming over TiO2 and CeO2 Pillared Clay Supported Au Catalysts

    Directory of Open Access Journals (Sweden)

    Rongbin Zhang

    2018-01-01

    Full Text Available Abstract: Methanol steam reforming is a promising process for the generation of hydrogen. In this study, Au catalysts supported on modified montmorillonite were prepared and their catalytic activity for methanol steam reforming was investigated at 250–500 °C. The physical and chemical properties of the as-prepared catalysts were characterized by Brunauer–Emmet–Teller method (BET, X-ray diffraction (XRD, transmission electron microscopic (TEM, scanning electron microscopy (SEM, X-ray photoelectron spectroscopy (XPS, Inductively Coupled Plasma (ICP, and thermogravimetrc analysis (TGA. For the catalysts examined, Au-Ti-Ce/Na-ABen exhibits the best catalytic performance with methanol conversion of 72% and H2 selectivity of 99% at 350 °C. This could be attributed to Au, Ce, and Ti species which form a solid solution and move into the interlayer space of the bentonite leading to a high surface area, large average pore volume, large average pore diameter, and small Au particle size. We considered that the synergistic effect of the crosslinking agent, the Ce species, and the Au active sites were responsible for the high activity of Au-Ti-Ce/Na-ABen catalyst for methanol steam reforming.

  20. O PROCESSO EROSIVO E A MATA CILIAR DO RIO ACARAÚ NA SERRA DAS MATAS (CE

    Directory of Open Access Journals (Sweden)

    José Falcão Sobrinho

    2005-01-01

    Full Text Available Le présent essai étudie l'intervention de l'action antrópica dans des secteurs de bois ciliar. Dans l'occasion se détachent lês processus érosifs liés à la forme d'utilisation du sol agricole.

  1. Cizinci na trhu práce v Jihočeském kraji

    OpenAIRE

    DUŠEK, Daniel

    2013-01-01

    The aim of this work is a comprehensive overview of third-country nationals on the labour market in South Bohemian region. It is primarily focused on a comparison of the number of foreigners in the labour market in the period 2007 - 2011 according to various districts of the region. This work is also focused on identifying major employers of third-country nationals in South Bohemia and theirs experience with workers from third countries. Besides literature review dealing with the labour migra...

  2. Bezdomovci a ich integrácia na trhu práce

    OpenAIRE

    Šprlák, Tomáš

    2009-01-01

    This thesis concerns the homelessness, which is an important problem of modern society. The problem is treated from the viewpoint of the integration of homeless people on the labour market. The theoretical part concerns the historical development of work as a factor of the social cohesion, labour market mechanisms with emphasis on the problem of the social exclusion, unemployment and homelessness. Empirical part shows the results of an inquiry realized on 23 homeless people in Prague and incl...

  3. Globalizace a její dopady na trh práce

    OpenAIRE

    Petríková, Monika

    2012-01-01

    The first chapter familiarizes with globalisation and defines it's basic fields of impacts. Within these impacts belong space-time compression, economic and environmental impacts, effects of globalisation on economic power of states and it also gives argumets for topic of inequality of economic and social growth. The second chapter describes impacts of globalisation on labour market. It concerns changes in international spatial division of labour and impacts on global unemployment, that is co...

  4. Energy migration in the Ce.sup.3+./sup. - doped Na-Gd phosphate glasses

    Czech Academy of Sciences Publication Activity Database

    Solovieva, Natalia; Nikl, Martin; Nitsch, Karel

    2007-01-01

    Roč. 30, - (2007), s. 113-115 ISSN 0925-3467 R&D Projects: GA AV ČR IAA200100626 Institutional research plan: CEZ:AV0Z10100521 Keywords : glasses * optical materials * luminescence spectra * condensed matter Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.519, year: 2007

  5. Ce and Eu activated Na2 Zn5 (PO4 )4 , a new promising novel ...

    Indian Academy of Sciences (India)

    Administrator

    /Eu. 3+ ions which is promising candidate for solid state lighting. Therefore, newly syn- thesised, by low cost and easy technique prepared, novel phosphors may be useful as RGB phosphor for solid state lighting application. Keywords. Photoluminescence; phosphor; solid state lighting; synthesis; phosphate. 1. Introduction.

  6. Ženský trh práce na Slovensku

    OpenAIRE

    Vinšová, Katarína

    2013-01-01

    This bachelor thesis summarises position of women in labour market in Slovakia. As a result of various prejudices and stereotypes women bear the so called double burden, meaning their professional and family life. In this thesis we describe the development of women's labour market in the world, in the European Union and also in Slovakia. We focus on individual indicators of their difficult position and later their comparison with the men's labour market. We analyse different forms of governme...

  7. Práce sestry na protialkoholní záchytné stanici

    OpenAIRE

    MRÁZKOVÁ, Radka

    2011-01-01

    The thesis at hand is titled The Work of a Nurse at a Sobering-up Station (hereinafter referred to as SUS). The theoretical part comprises of basic information on the SUS, its history, nurse?s responsibilities, admittance of a client, their examination, treatment, and a list of basic terms related to alcohol and their definitions. The paper is divided into four chapters: Alcohol and Alcoholism, Sobering-up Station, Characteristics of the Work of a Nurse, and Admittance of Clients. The objecti...

  8. Memória social e espacialidade de grupos ceramistas em Trairi, CE.

    OpenAIRE

    Nobre, João Nilo de Souza

    2013-01-01

    Pesquisas arqueológicas na planície litorânea de Trairi-CE nos levaram a buscar uma compreensão da relação espacial entre o Sítio Boa Esperança e os locais do seu entorno que apresentavam uma cultura material semelhante, destacando entre esses locais, o sítio Aldeia de Trairi, onde foram encontrados recipientes inteiros. A partir de dados obtidos em pesquisas anteriores levantamos a hipótese de que o sítio Boa Esperança é remanescente de uma aldeia e que as áreas do seu entorno que apresentam...

  9. Tvorba 3D modelu objektu ze snímků více kamer

    OpenAIRE

    Zemčík, Tomáš

    2016-01-01

    Tvorba 3D modelu objektu ze snímků několika kamer umožňuje bezkontaktní měření reálných objektů. Tato práce popisuje nutné teoretické a matematické zázemí pro pochopení problematiky a navrhuje možné hardwarové a softwarové řešení problému 3D rekonstrukce kukly se senzory EEG přímo na hlavě pacienta. Reconstruction of 3D model from multiple view images allows us to perform a contactless measurement of real world objects. This work contains theoretical and mathematical background necessary f...

  10. Response of Cs2LiYCl6:Ce (CLYC) to High Energy Protons

    International Nuclear Information System (INIS)

    Coupland, Daniel David Schechtman; Stonehill, Laura Catherine; Goett III, John Jerome

    2015-01-01

    Cs 2 LiYCl 6 :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 6 Li, and recent experiments have demonstrated sensitivity to fast neutrons through interactions with 35 Cl. 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.

  11. Levels in 146Ce and the N = 88 isotones

    International Nuclear Information System (INIS)

    Gowdy, G.M.; Chrien, R.E.; Chu, Y.Y.

    1981-01-01

    An investigation of the level structure of 146 Ce following the beta decay of the low-spin isomer of 146 La has been carried out at the ISOL facility TRISTAN at Brookhaven National Laboratory. The half-life for the low spin isomer was found to be 6.0 +- 0.4s. A partial level scheme for 146 Ce below 2 MeV is given. The level energies and some B(E2) values extracted from our data have been compared with IBA-2 calculations done entirely with extrapolated parameters from neighboring Z nuclei in order to check the predictive power of the model. Systematics of the Z = 58 isotopes and N = 88 isotones indicate that although 146 Ce is more deformed than its isotones with Z greater than or equal to 60, the transition to the well-deformed region can probably more correctly be thought to occur after 146 Ce, between N = 88 and N = 90, as it does for Z greater than or equal to 60. The abrupt onset of deformation present in the higher Z isotopes is not seen in the Ce isotopes where the trend is found to be rather smooth throughout

  12. 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.

  13. Luminance behavior of Ce3+ doped ZnS nanostructures.

    Science.gov (United States)

    Shanmugam, N; Cholan, S; Kannadasan, N; Sathishkumar, K; Viruthagiri, G

    2014-01-24

    We report the synthesis and characterization of undoped and various levels of Ce(3+) doped ZnS nanocrystal. The structure and size of the products were studied by X-ray diffraction (XRD). The existence of functional groups was identified by Fourier transform infrared spectrometry (FT-IR). The UV-Visible measurements reveal that the synthesized products are blue shifted when compared with bulk phase of ZnS as a result of quantum confinement effect. The PL studies show an enhancement in the intensity of emission band in the UV region on increased Ce(3+) doping. The morphology of the products was evaluated by Field emission scanning electron microscope (FESEM) and High resolution transmission electron microscopy (FESEM). The presence of Ce(3+) was confirmed by Energy dispersive spectral analysis (EDS). The thermal stability of pure and doped products was analyzed by thermo gravimetric and differential thermal analysis (TG-DTA). Copyright © 2013 Elsevier B.V. All rights reserved.

  14. 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.

  15. Cooperative effects in CeCu2Si2

    International Nuclear Information System (INIS)

    Lang, M.; Modler, R.; Ahlheim, U.; Helfrich, R.; Reinders, P.H.P.; Steglich, F.; Assmus, W.; Sun, W.; Bruls, G.; Weber, D.; Luethi, B.

    1991-01-01

    Heavy-fermion superconductivity and other cooperative effects have been explored by thermal expansion, specific heat and ultrasound measurements on CeCu 2 Si 2 single crystals. Crystals annealed under Cu atmosphere show sharp superconducting transitions at Tc max =0.63 K. At the same temperature the ''as grown'', i.e., non-bulk-superconducting, crystals reveal a pronounced phase-transition anomaly, presumably of structural origin. This new transition is associated with an expansion of the volume upon cooling and gives rise to magnetic correlations. Our results indicate a complex interplay between lattice instability, magnetic phenomena and superconductivity in CeCu 2 Si 2 . (orig.)

  16. Magnetic properties of Ce3+ in PbCeA (A= Te, Se, S)

    Science.gov (United States)

    Isber, S.; Gratens, X.; Charar, S.; Golacki, Z.

    2013-01-01

    The magnetic susceptibility of Pb1-xCexA (A = S, Se and Te) crystals with 0.006 ≤ x ≤ 0.036 were studied in the temperature range from 20 mK up to room temperature. X-band (~9.5 GHz) Electron Paramagnetic Resonance (EPR) showed small shifts in the effective Landé factors that were attributed to crystal-field admixture. The EPR measurements were correlated with the magnetic susceptibility data and resulted in estimating the crystal-field splitting Δ = E(Γ8) - E(Γ7) of the lowest 2F5/2 manifold for Ce3+ ions in PbA (A = S, Se and Te) of about 340 K, 440 K and 540 K for Pb1-xCexTe, Pb1-xCexSe, and Pb1-xCexS, respectively. The values for the crystal-field splitting deduced from the magnetic data were found to be in agreement with the calculated ones based on the point charge model. Moreover, the deHaas van-Alphen magnetic oscillations in the susceptibility measurements of Pb1-xCexTe (x~ 0.05 and 0.07) were observed at ultra-low temperature (20 mK); The oscillations were investigated and the values of the oscillatory period for Pb1-xCexTe (x = 0.0048 and 0.007) are reported.

  17. Studies of the Ce(III)/Ce(IV) couple in multiphase systems containing a phase transfer reagent: Pt. 2

    International Nuclear Information System (INIS)

    Pletcher, D.; Valdes, E.M.

    1988-01-01

    The oxidation of some toluenes and aromatic hydrocarbons by Ce(IV) in aqueous nitric acid/organic solvent emulsions containing a phase transfer reagent, tributylphosphate or tetrabutylammonium ion are reported. With toluenes, a number of products are formed and the relative yield depends most strongly on substituents; with p-xylene and p-methoxytoluene, reasonable yields of aldehydes were obtained with short reaction times. With anthracene and naphthalene, the reactions are again fast and good yields of quinones are observed. On the basis of these studies it is possible to select conditions for the indirect oxidation of some organic molecules in an emulsion and using Ce(III)/Ce(IV) as the redox mediator. (author)

  18. Non-aqueous CE-MS of cinchona alkaloids - characterizationof a novel CE-ESI-MS interface

    DEFF Research Database (Denmark)

    Hansen, Frederik André; Hansen, Steen Honoré; Petersen, Nickolaj J.

    a submicron fracture in the capillary close the ESI tip. The fracture provides a zero dead volume and excellent conducting properties due to the large amount of ions in the electric double layer. Electric current exceeding the upper limit of CE instrumentation of up to 300 µA can easily be obtained...... 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...

  19. Magnetic domains and frustration in metallic CePdAl

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, Stefan; Huesges, Zita; Huang, Chien-Lung; Stockert, Oliver [Max Planck Institute CPfS, Dresden (Germany); Fritsch, Veronika; Sakai, Akito [EP 6, Electronic Correlations and Magnetism, University of Augsburg (Germany); Grube, Kai; Taubenheim, Christian; Loehneysen, Hilbert von [Karlsruhe Institute of Technology (Germany)

    2016-07-01

    Magnetic frustration is an exciting topic in condensed matter physics, since it can lead to new ground states of materials, e.g. a spin liquid or spin glass state. Effects of magnetic frustration have been investigated intensively for insulating materials. However, the existence of magnetic frustration in metallic systems is still under debate. CePdAl is a metallic Kondo system, where geometric magnetic frustration arises from the formation of Ce ions on a distorted Kagome lattice. Neutron scattering experiments revealed, that only two thirds of the magnetic Ce moments order antiferromagnetically below T{sub N}=2.7 K, whereas the other third remains mainly disordered. Thermodynamic as well as neutron scattering measurements are presented to verify the existence of partial magnetic frustration in CePdAl. Recently neutron diffraction experiments under magnetic fields applied along two orthogonal directions in the magnetically hard basal plane were performed. They show opposite effects on the magnetic intensity of a selected magnetic domain depending on the field direction with respect to the propagation vector. If this is only an effect of different domain population or also due to a change in magnetic frustration shall be discussed.

  20. Preparation and properties of Pr /Ce :YAG phosphors using ...

    Indian Academy of Sciences (India)

    2015-09-01

    Sep 1, 2015 ... The relatively higher pH could decrease the loss of Ce and Pr in the precursors and increase the particle size of the obtained powders, which was beneficial to the enhancement of luminescent intensity. Therefore, the precursors directly converted to pure-phase YAG at 900◦C, and the phosphors calcined at ...

  1. Optical properties of CeO2 thin films

    Indian Academy of Sciences (India)

    TECS

    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.

  2. Antiferromagnetism and hot spots in CeIn3

    Science.gov (United States)

    Grigoriev, Pavel; Gor'kov, Lev

    2006-03-01

    Enormous mass enhancement at ``hot spots'' on the Fermi surface (FS) of the antiferromagnetic CeIn3 has been reported at strong magnetic field near its antiferromagnetic quantum critical point [T. Ebihara et al., Phys. Rev. Lett. 93, 246401 (2004)]. The effect was ascribed to anomalous spin fluctuations at these spots owing to peculiar strong many-body interactions. The ``hot spots'' lie at the positions on FS same as in non-magnetic LaIn3 where the narrow necks are protruded, thus, hinting on their possible relation. Assuming that in paramagnetic phase CeIn3 has similar spectrum, we study the influence of the antiferromagnetic ordering (AFM) on the energy spectrum of CeIn3 and show that its FS undergoes a topological change at the onset of AFM. The necks at the ``hot spots'' are truncated by the AFM, thus restoring the almost spherical d-part of the FS of CeIn3. Applied field suppresses the AFM and restores the necks on the FS (so-called 2.5-order phase transition) leading to logarithmic divergence of the dHvA effective mass when the electron trajectory passes near or through the restored necks. This effect fully explains the observed dHvA mass enhancement in the ``hot spots'' in the frameworks of one-particle approximation and leads to the predictions concerning the spin-dependence of the effective electron mass.

  3. Preparation and properties of Pr /Ce :YAG phosphors using ...

    Indian Academy of Sciences (India)

    2015-09-01

    Sep 1, 2015 ... 3+. :YAG phosphors using triethanolamine as dispersant and pH regulator. SHIHONG TONG. ∗. , JUNYAN ZHAO and XIU WEN. College of Sciences of Southwest Petroleum .... were weighted in the molar ratio of 0.015:0.06:2.925:5 and ... Pr3+/Ce3+:YAG powders were investigated by X-ray diffrac-.

  4. Diffusion of hydrogen in Pd-(Ce, Y, B) alloys

    International Nuclear Information System (INIS)

    Sakamoto, Y.; Kaneko, H.; Tsukahara, T.; Hirata, S.

    1987-01-01

    The study has been carried out to determine the diffusivity of hydrogen in Pd alloys containing Ce, Y and B in atom fractions up to θ/sub μ/ = 0.1 by an electrochemical permeation method, and to examine the lattice dilation effect on the diffusivity in these alloys. Ce and Y have been chosen because the solid solubility of both in Pd is about 13 at% in spite of the very large atomic size-factor difference between Pd and the solutes, and thus the expansion of the Pd lattice by Ce and Y is much larger than by Ag. Furthermore, it is of interest that the partial enthalpy of the dissolved hydrogen at infinite dilution ΔH 0 /sub H/ for Ce and Y is much smaller than for Pd. On the other hand, B atom also expands the Pd lattice in a way similar to Y, and sometimes B atoms may dissolve in the octahedral interstitial sites in the same way as hydrogen atoms

  5. Nuclear data treatment for SAM-CE Monte Carlo calculations

    International Nuclear Information System (INIS)

    Lichtenstein, H.; Troubetzkoy, E.S.; Beer, M.

    1980-01-01

    The treatment of nuclear data by the SAM-CE Monte Carlo code system is presented. The retrieval of neutron, gamma production, and photon data from the ENDF/B fils is described. Integral cross sections as well as differential data are utilized in the Monte Carlo calculations, and the processing procedures for the requisite data are summarized

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

    Digital Repository Service at National Institute of Oceanography (India)

    Sadhuram, Y.

    The bulk transfer coefficient for latent heat flux (Ce) has been estimated over the Arabian Sea from the moisture budget during the pre-monsoon season of 1988. The computations have been made over two regions (A: 0-8 degrees N: 60-68 degrees E: B: 0...

  7. 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.

  8. Information System through ANIS at CeSAM

    Science.gov (United States)

    Moreau, C.; Agneray, F.; Gimenez, S.

    2015-09-01

    ANIS (AstroNomical Information System) is a web generic tool developed at CeSAM to facilitate and standardize the implementation of astronomical data of various kinds through private and/or public dedicated Information Systems. The architecture of ANIS is composed of a database server which contains the project data, a web user interface template which provides high level services (search, extract and display imaging and spectroscopic data using a combination of criteria, an object list, a sql query module or a cone search interfaces), a framework composed of several packages, and a metadata database managed by a web administration entity. The process to implement a new ANIS instance at CeSAM is easy and fast : the scientific project has to submit data or a data secure access, the CeSAM team installs the new instance (web interface template and the metadata database), and the project administrator can configure the instance with the web ANIS-administration entity. Currently, the CeSAM offers through ANIS a web access to VO compliant Information Systems for different projects (HeDaM, HST-COSMOS, CFHTLS-ZPhots, ExoDAT,...).

  9. Optical properties of CeO2 thin films

    Indian Academy of Sciences (India)

    TECS

    increase with increase in thickness. The values of absorp- tion coefficient, extinction coefficient, refractive index, dielectric constant, phase angle and loss angle were found to be in conformity with previous works. From the X-ray diffraction studies it is found that CeO2 thin film has crys- talline structure and a smaller crystallite ...

  10. Burstein Moss effect in nanocrystalline CaS: Ce

    Indian Academy of Sciences (India)

    Administrator

    Burstein Moss effect in nanocrystalline CaS: Ce. GEETA SHARMA*, PUJA CHAWLA, S P LOCHAB. † and NAFA SINGH. Department of Physics, Kurukshetra University, Kurukshetra 136 119, India. †. Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067, India. MS received 27 July 2009; revised 16 ...

  11. 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...

  12. Ce que PMNT finance Promotion d'une alimentation saine

    International Development Research Centre (IDRC) Digital Library (Canada)

    Ce que PMNT finance. Promotion d'une alimentation saine. Comprendre le contexte d'élaboration des politiques. Analyses situationnelles portant sur les politiques relatives à une alimentation saine : analyse situationnelle du niveau de mesures de lutte sont mises en œuvre (contrôle exercé sur la disponibilité, le prix de ...

  13. Properties of polyamorphous Ce75Al25 metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Q.-S.; Struzhkin, Viktor V.; Fang, Y. Z.; Gao, C. X.; Luo, H. B.; Wang, X. D.; Lathe, C.; Mao, Wendy L.; Wu, F. M.; Mao, Ho-kwang; Jiang, J. Z.

    2010-08-17

    The thermal stability and electronic transport properties of polyamorphous Ce{sub 75} Al{sub 25} metallic glass (MG) have been investigated using in situ high-pressure, high-temperature, energy-dispersive synchrotron x-ray diffraction and in situ high-pressure and low-temperature, four-probe resistance measurements. The results are compared with the properties of La{sub 75} Al{sub 25} MG. The pressure dependence of the crystallization temperature and resistance of the Ce{sub 75} Al{sub 25} MG exhibited turning points at the polyamorphic transition pressure, 1.5 GPa, and they clearly presented different behaviors below and above 1.5 GPa. In contrast, no turning points were observed in the La{sub 75} Al{sub 25} MG (La has no 4f electron). Additionally, the pressure-tuned temperature coefficient of resistance of the Ce{sub 75} Al{sub 25} MG was observed. These results revealed switchable properties in the polyamorphous Ce{sub 75} Al{sub 25} MG that are linked with 4f electron delocalization.

  14. d-AO spherical aromaticity in Ce6O8.

    Science.gov (United States)

    Yu, Xiaohu; Oganov, Artem R; Popov, Ivan A; Boldyrev, Alexander I

    2016-01-05

    After the first introduction of π aromaticity in chemistry to explain the bonding, structure, and reactivity of benzene and its derivatives, this concept was further applied to many other compounds featuring other types of aromaticity (i.e., σ, δ). Thus far, there have been no reports on d-AO-based spherical σ aromaticity. Here, we predict a highly stable bare Ce6O8 cluster of a spherical shape using evolutionary algorithm USPEX and DFT + U calculations. Natural bond orbital analysis, adaptive natural density partitioning algorithm, electron localization function, and partial charge plots demonstrate that bare Ce6O8 cluster exhibits d-AO spherical σ aromaticity, thus explaining its exotic geometry and stability. Ce6O8 complex plays an important role in many reactions and is known to exist in many forms, such as in NH4[Ce6(μ(3)O)5(μ(3)OH)3(μ(2)-C6H5COO)9(NO3)3(DMF)3]*DMF*H2O compound, which is prepared under room temperature, and acts as an oxidizing agent. © 2015 Wiley Periodicals, Inc.

  15. Geometry modeling for SAM-CE Monte Carlo calculations

    International Nuclear Information System (INIS)

    Steinberg, H.A.; Troubetzkoy, E.S.

    1980-01-01

    Three geometry packages have been developed and incorporated into SAM-CE, for representing in three dimensions the transport medium. These are combinatorial geometry - a general (non-lattice) system, complex combinatorial geometry - a very general system with lattice capability, and special reactor geometry - a special purpose system for light water reactor geometries. Their different attributes are described

  16. Dynamical magnetic response of paramagnetic CeFe-2

    International Nuclear Information System (INIS)

    Rainford, B.D.; McK Paul, D.; Warwick Univ., Coventry

    1988-01-01

    Inelastic neutron scattering has been used to study the energy dependence of the paramagnetic response from CeFe 2 . Our results, when integrated over energy, are in excellent agreement with the polarised neutron experiments of Deportes et al., but the correlation length obtained by fitting the data to a double Lorentzian scattering function is significantly smaller than that derived previously

  17. 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

  18. The Roll of NaPSS Surfactant on the Ceria Nanoparticles Embedding in Polypyrrole Films

    Directory of Open Access Journals (Sweden)

    Simona Popescu

    2016-01-01

    Full Text Available Cerium oxide nanoparticles (CeO2 NPs in crystalline form have been synthesized by a coprecipitation method. CeO2 nanoparticles were then embedded in polypyrrole (PPy films during the electropolymerization of pyrrole (Py on titanium substrate. The influence of poly(sodium 4-styrenesulfonate (NaPSS surfactant used during polymerization on the embedding of CeO2 NPs in polypyrrole films was investigated. The new films were characterized in terms of surface analysis, wettability, electrochemical behaviour, and antibacterial effect. The surface and electrochemical characterization revealed the role of surfactant on PPy doping process cerium oxide incorporation. In the presence of surfactant, CeO2 NPs are preferentially embedded in the polymeric film while, without surfactant, the ceria nanoparticles are quasiuniformly spread as agglomerates onto polymeric films. The antibacterial effect of studied PPy films was substantially improved in the presence of cerium oxide and depends by the polymerization conditions.

  19. POLLiCE (POLLen in the iCE): climate history from Adamello ice cores

    Science.gov (United States)

    Cristofori, Antonella; Festi, Daniela; Maggi, Valter; Casarotto, Christian; Bertoni, Elena; Vernesi, Cristiano

    2017-04-01

    Glaciers can be viewed as the most complete and effective past climate and environment archives severely threatened by climate change. These threats are particularly dramatic across European Alps. The Adamello glacier is the largest, 16.4 km2, and deepest, 270 m, Italian glacier. We aim at estimating biodiversity changes over the last centuries in relation to climate and human activities in the Adamello catchment area. We, therefore, recently launched the POLLiCE project (pollice.fmach.it) for specifically targeting the biological component (e.g. pollen, leaves, plant remains) trapped in ice cores. Classical morphological pollen analysis will be accompanied by DNA metabarcoding. This approach has the potential to provide a detailed taxonomical identification - at least genus level- thus circumventing the limitations of microscopic analysis such as time-consuming procedures and shared features of pollen grains among different taxa. Moreover, ice cores are subjected to chemical and physical analyses - stable isotopes, ions, hyperspectral imaging, etc.- for stratigraphic and climatic determination of seasonality. A pilot drilling was conducted on March 2015 and the resulting 5 m core has been analysed in terms of pollen spectrum, stable isotopes and ions in order to demonstrate the feasibility of the study. The first encouraging results showed that even in this superficial core a stratigraphy is evident with indication of seasonality as highlighted by both by pollen taxa and stable isotopes. Finally, DNA has been successfully extracted and amplified with specific DNA barcodes. A medium drilling was performed on April 2016 with the extraction of a 45 m ice core. The analysis of this core constitutes the subject of a specific research project, CALICE*, just funded by Euregio Science Fund (IPN57). The entire depth, 270 m, of the Adamello glacier is scheduled to be drilled in 2018 winter to secure the unique memory archived by the ice. * See EGU2017 poster by Festi et al

  20. Magnetic properties of Ce3+ in PbCeA (A= Te, Se, S

    Directory of Open Access Journals (Sweden)

    Golacki Z.

    2013-01-01

    Full Text Available The magnetic susceptibility of Pb1-xCexA (A = S, Se and Te crystals with 0.006 ≤  x ≤ 0.036  were studied in the temperature range from 20 mK up to room temperature. X-band (~9.5 GHz Electron Paramagnetic Resonance (EPR showed small shifts in the effective Landé factors that were attributed to crystal-field admixture. The EPR measurements were correlated with the magnetic susceptibility data and resulted in estimating the crystal-field splitting Δ = E(Γ8 - E(Γ7 of the lowest 2F5/2 manifold for Ce3+ ions in PbA (A = S, Se and Te of about 340 K, 440 K and 540 K for Pb1-xCexTe, Pb1-xCexSe, and Pb1-xCexS, respectively. The values for the crystal-field splitting deduced from the magnetic data were found to be in agreement with the calculated ones based on the point charge model. Moreover, the deHaas van-Alphen magnetic oscillations in the susceptibility measurements of Pb1-xCexTe (x~ 0.05 and 0.07 were observed at ultra-low temperature (20 mK; The oscillations were investigated and the values of the oscillatory period for Pb1-xCexTe (x = 0.0048 and 0.007 are reported.

  1. Ammonia excretion in Caenorhabditis elegans: mechanism and evidence of ammonia transport of the Rhesus protein CeRhr-1

    Science.gov (United States)

    Adlimoghaddam, Aida; Boeckstaens, Mélanie; Marini, Anna-Maria; Treberg, Jason R.; Brassinga, Ann-Karen C.; Weihrauch, Dirk

    2015-01-01

    ABSTRACT The soil-dwelling nematode Caenorhabditis elegans is a bacteriovorous animal, excreting the vast majority of its nitrogenous waste as ammonia (25.3±1.2 µmol gFW−1 day−1) and very little urea (0.21±0.004 µmol gFW−1 day−1). Although these roundworms have been used for decades as genetic model systems, very little is known about their strategy to eliminate the toxic waste product ammonia from their bodies into the environment. The current study provides evidence that ammonia is at least partially excreted via the hypodermis. Starvation reduced the ammonia excretion rates by more than half, whereas mRNA expression levels of the Rhesus protein CeRhr-2, V-type H+-ATPase (subunit A) and Na+/K+-ATPase (α-subunit) decreased correspondingly. Moreover, ammonia excretion rates were enhanced in media buffered to pH 5 and decreased at pH 9.5. Inhibitor experiments, combined with enzyme activity measurements and mRNA expression analyses, further suggested that the excretion mechanism involves the participation of the V-type H+-ATPase, carbonic anhydrase, Na+/K+-ATPase, and a functional microtubule network. These findings indicate that ammonia is excreted, not only by apical ammonia trapping, but also via vesicular transport and exocytosis. Exposure to 1 mmol l−1 NH4Cl caused a 10-fold increase in body ammonia and a tripling of ammonia excretion rates. Gene expression levels of CeRhr-1 and CeRhr-2, V-ATPase and Na+/K+-ATPase also increased significantly in response to 1 mmol l−1 NH4Cl. Importantly, a functional expression analysis showed, for the first time, ammonia transport capabilities for CeRhr-1 in a phylogenetically ancient invertebrate system, identifying these proteins as potential functional precursors to the vertebrate ammonia-transporting Rh-glycoproteins. PMID:25740900

  2. 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 ST...

  3. Crystal growth and scintillation properties of multi-component oxide single crystals: Ce:GGAG and Ce:La-GPS

    Czech Academy of Sciences Publication Activity Database

    Yoshikawa, A.; Kamada, K.; Kurosawa, S.; Shoji, Y.; Yokota, Y.; Chani, V.I.; Nikl, Martin

    2016-01-01

    Roč. 169, Jan (2016), s. 387-393 ISSN 0022-2313. [International Conference on Luminescence and Optical Spectroscopy of Condensed Matter /17./. Wroclaw, 13.07.2014-18.07.2014] Institutional support: RVO:68378271 Keywords : scintillator * luminescent materials * Ce 3+ * radioluminescence Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.686, year: 2016

  4. The investigation of Ce doped ZnO crystal: The electronic, optical and magnetic properties

    Science.gov (United States)

    Wen, Jun-Qing; Zhang, Jian-Min; Qiu, Ze-Gang; Yang, Xu; Li, Zhi-Qin

    2018-04-01

    The electronic, optical and magnetic properties of Ce doped ZnO crystal have been studied by using first principles method. The research of formation energies show that Ce doped ZnO is energetically stable, and the formation energies reduce from 6.25% to 12.5% for Ce molar percentage. The energy band is still direct band gap after Ce doped, and band gap increases with the increase of Cesbnd Ce distance. The Fermi level moves upward into conduction band and the DOS moves to lower energy with the increase of Ce concentration, which showing the properties of n-type semiconductor. The calculated optical properties imply that Ce doped causes a red-shift of absorption peaks, and enhances the absorption of the visible light. The transition from ferromagnetic to antiferromagnetic has been found in Ce doped ZnO.

  5. New NaSrPO4: Sm 3 phosphor as orange-red emitting material

    Indian Academy of Sciences (India)

    Phosphors; temperature; conventional solid-state sintering; luminescence. ... NaSr 1 − x PO 4 : x Sm 3 + phosphor shows a higher thermally stable luminescence and its thermal quenching temperature T 50 was found to be 350 ∘ C, which is higher than that of commercial YAG:Ce 3 + phosphor and ZnS:(Al, Ag) phosphor.

  6. Ce3+ įtaka α-pusvandenio gipso susidarymui

    Directory of Open Access Journals (Sweden)

    Nora KYBARTIENĖ

    2012-12-01

    Full Text Available Lietuvoje gamtinio dvivandenio gipso, tinkamo gipsinių rišamųjų medžiagų gamybai, nėra. Jį galima būtų pakeisti fosfogipsu (pusvandeniu ar dvivandeniu, kuris susidaro fosforo rūgšties gamybos metu, skaidant fosfatines žaliavas sieros rūgštimi. Priklausomai nuo fosfatinėje žaliavoje esančių priemaišų susidaręs fosfogipsas skiriasi kristalų morfologija ir savybėmis. Fosfogipsas yra daugiakomponentis junginys. Siekiant atsiriboti nuo kitų junginių ir įvertinti Ln3+ įtaką pusvandenio fosfogipso kristalų morfologijai, tikslinga sudaryti modelinę dvikomponentę sistemą: dvivandenis gipsas – lantanoidai. Darbe tirta Ce3+ įtaka α-pusvandenio gipso susidarymui. Sudaryta modelinė sistema: CaSO4·2H2O–Ce2(SO43×8H2O. Į sistemą įmaišytas toks Ce2(SO43×8H2O kiekis, kad Ce2O3 koncentracija būtų 0,1; 0,5 ir 1 % ir būtų artima fosfatinėse žaliavose esančiam jų kiekiui. Sistema apdorota hidroterminėmis sąlygomis 128 oC ir 138 oC temperatūroje, izoterminio išlaikymo trukmė – 3 h. Produktas gautas iškaitinus 400 °C temperatūroje. Atlikta produkto rentgeno spinduliuotės difrakcinė analizė, FT-IR spektrinė analizė ir mikroskopinė analizė (SEM. Gauti rezultatai parodė, kad kuo didesnis Ce3+ kiekis yra sistemoje, tuo daugiau nedehidratavusio dvivandenio gipso lieka gautame produkte, o susidariusio α- pusvandenio gipso kristalai yra smulkūs, neaiškios, neapibrėžtos formos. Taigi, galima teigti, kad Ce3+ turi neigiamą įtaką dvivandenio gipso dehidratacijai, t. y. α- pusvandenio gipso susidarymui, ir pusvandenio gipso kristalų morfologijai.DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3102

  7. Podnikatelský start-up brašny na kolo – Bishbag

    OpenAIRE

    Nesvadba, Lukáš

    2016-01-01

    Tato bakalářská práce se zaměřuje na podnikatelský záměr pro začínající společnost nabízející koženou brašnou přes rameno, která je lehce přizpůsobitelná na přední řídítka na kole. Práce je rozdělena na teoretickou a praktickou část. Práce zahrnuje teoretické poznatky z oblasti podnikání, potřebné k vypracování podnikatelského záměru. Praktická část se zaměřuje na vypracování podnikatelského start-upu pro výrobek Bishbag. Obsahuje návrh start-upu a ukazuje na možnosti realizace, marketing jak...

  8. Topotactic Transformation Route to Monodisperse β-NaYF4:Ln(3+) Microcrystals with Luminescence Properties.

    Science.gov (United States)

    Shao, Baiqi; Feng, Yang; Song, Yan; Jiao, Mengmeng; Lü, Wei; You, Hongpeng

    2016-02-15

    A novel nonorganic wet route for direct synthesis of uniform hexagonal β-NaYF4:Ln(3+) (Ln = Eu, Tb, Ce/Tb, Yb/Er, and Yb/Tm) microcrystals with various morphologies has been developed wherein the intermediate routine cubic-hexagonal (α → β) phase transfer process was avoided. The morphology can be effectively tuned into hexagonal disc, prism, and novel hierarchical architectures by systematically fine manipulating the Na2CO3/F(-) feeding ratio. It has been found that the routine α → β phase transfer for NaYF4 was not detected during the growth, while NaY(CO3)F2 emerged in the initial reaction stage and fast transformed into β-NaYF4 via a novel topotactic transformation behavior. Detailed structural analysis showed that β-NaYF4 preferred the [001] epitaxial growth direction of NaY(CO3)F2 due to the structural matching of [001]NaY(CO3)F2//[0001]β-NaYF4. Besides, the potential application of the as-prepared products as phosphors is emphasized by demonstrating multicolor emissions including downconversion, upconversion, and energy transfer (Ce-Tb) process by lanthanides doping.

  9. Yb and Er co-doped Y2Ce2O7 nanoparticles: synthesis and ...

    Indian Academy of Sciences (India)

    Xu et al 2010). In addition, Er3+ ion has abundant energy level structure, so green and red upconversion emissions can be realized in Er3+-doped materials. .... Ce. Count. Engergy (KeV). Ce. O Y. Yb. Ce. Cu. Er. Figure 2. Energy dispersive spectra of Yb3+ and Er3+ co-doped. Y2Ce2O7 nanoparticles prepared for 4 h at ...

  10. Structure and phase composition of Al-Ce-Cu system alloys in range of quasi-binary Al-Al8CeCu4 section

    International Nuclear Information System (INIS)

    Belov, N.A.; Khvan, A.V.

    2007-01-01

    The phase diagram of the Al-Cu-Ce system in the quasibinary section area of Al-Al 8 CeCu 4 has been investigated by metallographic, thermal, micro-X-ray spectral and X-ray structural analyses. The parameters of the eutectic reaction L→(Al)+CeCu 4 Al 8 : T=610 Deg C were found out; the composition was 14% Cu and 7% Ce. This eutectics is of a disperse structure and the ternary compound contained is capable of fragmentation and spheroidizing in the heating process (starting from 540 Deg C). It was demonstrated that the area of optimal (Al)+CeCu 4 Al 8 eutectics-based alloy compositions was within the narrow limits. That is related to the fact that at a comparatively little variation of the Cu:Ce=2 ratio solidus sharply decreases and, as a result, the crystallization interval considerably extends [ru

  11. Ce3+/Eu2+ doped SrSc2O4 phosphors: Synthesis, luminescence and energy transfer from Ce3+ to Eu2+

    Science.gov (United States)

    Zhao, Jitao; Sun, Xiaoyu; Wang, Zhenqing

    2018-01-01

    Ce3+/Eu2+ doped SrSc2O4 phosphors were synthesized by a solid state reaction. The phase and luminescent properties of the synthesized phosphors were investigated. In SrSc2O4 host, Ce3+/Eu2+ substitute Sr2+ sites and form the solid solution. Ce3+/Eu2+ singly doped SrSc2O4 phosphors respectively show emission band locating in green and deep red regions and the emission peaks shift to longer wavelength with the increasing concentration due to the enhancements of crystal field. In Ce3+/Eu2+ codoped SrSc2O4 phosphors, the intensities of Ce3+ and Eu2+ emissions change with the changing Eu2+ concentrations due to energy transfer from Ce3+ to Eu2+.

  12. Energy transfer from Ce3+ to Eu3+ through Tb3+ chain in YPO4:Ce3+/Tb3+/Eu3+ phosphors

    Science.gov (United States)

    Yang, Yuguo; Lv, Xianshun; Wei, Lei; Xu, Jianhua; Yu, Huajian; Hu, Yanyan; Zhang, Huadi; Liu, Bing; Wang, Xuping; Li, Qinggang

    2018-01-01

    We synthesized a series of YPO4:Ce3+/Tb3+/Eu3+ phosphors by a solid state reaction. All of phosphors have a single phase, showing that the doping ions could not change the phase of YPO4 host. The emission intensities of Ce3+, Tb3+ and Eu3+ ions clearly depend on the Tb3+ concentrations in YPO4:Ce3+/Tb3+/Eu3+ phosphors. The emission intensity of Ce3+ emission decreases gradually but the emission intensity of Eu3+ emission increases continuously with the increasing Tb3+ concentration because of the energy transfer from Ce3+ to Eu3+ through Tb3+. On the basis of the luminescent properties of YPO4:Ce3+/Tb3+/Eu3+ phosphors, the possible energy transfer mechanism was speculated.

  13. Effect of Ce on solidification and mechanical properties of A360 alloy

    International Nuclear Information System (INIS)

    Voncina, Maja; Kores, Stanislav; Mrvar, Primoz; Medved, Jozef

    2011-01-01

    Highlights: → We investigated the effect of Ce addition on the AA A360 alloy. → The purpose is to study the variations that occur during solidification and precipitation with different Ce additions, as well as their effect on the mechanical properties. → Ce addition decreases the eutectic (α Al + Mg 2 Si) temperature and eutectic recalescence and also solidus temperature. → The precipitation enthalpy decreases with the Ce addition, while precipitation takes place more rapidly and intensively, indicating increased reaction kinetics. → The mechanical properties like hardness and tensile strength also increase with the Ce addition. - Abstract: The effect of Ce addition on the AA A360 (Al-10%Si-0.5%Mg) alloy was investigated using equilibrium thermodynamic calculation, thermal analysis, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The purpose is to study the variations that occur during solidification and precipitation with different Ce additions, as well as their effect on the mechanical properties. The results show that the Ce addition decreases the eutectic (α Al + Mg 2 Si) temperature. The solidus temperature also decreases with the increasing Ce addition. The precipitation enthalpy determined using DSC decreases with the Ce addition, while precipitation takes place more rapidly and intensively, indicating increased reaction kinetics. The mechanical properties like hardness and tensile strength also increase with the Ce addition. The phase that contributed to the hardness of the investigated alloy was composed of Al, Ce, Mg and Si.

  14. Laser-excited spectra of Lu2SiO5:Ce scintillator

    International Nuclear Information System (INIS)

    Liu Bo; Gu Mu; Qi Zeming; Shi Chaoshu; Yin, Min; Ren Guohao

    2007-01-01

    The emission spectra of Lu 2 SiO 5 :Ce single crystal under the excitation of 266 nm laser were investigated. The emission spectra of LSO single crystal show no temperature quenching from 20 to 300 K, under the excitation of 266 nm laser with 2 mJ pulse energy. With rising temperature, the Ce1 emission is slightly decreased, while the Ce2 emission is slightly increased. These results show the emissions of Ce1 and Ce2 is not only dependent on the concentration ratio but also influenced by the possible energy transfer processes, including Ce1 to Ce2, intrinsic STHs to Ce2 and the phonon-assisted transfer processes. The spectral thermal broadening and the spectral overlap become evident at high temperature, leading to the enhancement of energy transfer. When the excitation power lowers, the ratio of Ce1 and Ce2 emission increases, and is close to the Xe lamp ultraviolet (UV) excitation, suggesting that the energy transfer from Ce1 center to Ce2 center may be also dependent on the excitation power

  15. Study of structural and electronic transport properties of Ce-doped ...

    Indian Academy of Sciences (India)

    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 ...

  16. Redox enzyme-mimicking activities of CeO2nanostructures: Intrinsic influence of exposed facets.

    Science.gov (United States)

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

    2016-10-17

    CeO 2 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 Ce 3+ /Ce 4+ ratio and oxygen vacancies on the surface have been considered as the major originations responsible for the redox enzyme-mimicking activities of CeO 2 NPs. Herein, CeO 2 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 Ce 3+ /Ce 4+ ratio and oxygen vacancy content on the surfaces of as-synthesized CeO 2 nanostructures are nearly at the same levels. Meanwhile, the enzymatic activity measurements indicate that the redox enzyme-mimicking activities of as-synthesized CeO 2 nanostructures are greatly dependent on their exposed facets. CeO 2 nanocubes with exposed {100} facets exhibit a higher peroxidase but lower superoxide dismutase activity than those of the CeO 2 nanorods with exposed {110} facets. Our results provide new insights into the redox enzyme-mimicking activities of CeO 2 nanostructures, as well as the design and synthesis of inorganic nanomaterials-based artificial enzymes.

  17. Heteroaggregation, transformation and fate of CeO2 nanoparticles in wastewater treatment

    International Nuclear Information System (INIS)

    Barton, Lauren E.; Auffan, Melanie; Olivi, Luca; Bottero, Jean-Yves; Wiesner, Mark R.

    2015-01-01

    Wastewater Treatment Plants (WWTPs) are a key pathway by which nanoparticles (NPs) enter the environment following release from NP-enabled products. This work considers the fate and exposure of CeO 2 NPs in WWTPs in a two-step process of heteroaggregation with bacteria followed by the subsequent reduction of Ce(IV) to Ce(III). Measurements of NP association with solids in sludge were combined with experimental estimates of reduction rate constants for CeO 2 NPs in Monte Carlo simulations to predict the concentrations and speciation of Ce in WWTP effluents and biosolids. Experiments indicated preferential accumulation of CeO 2 NPs in biosolids where reductive transformation would occur. Surface functionalization was observed to impact both the distribution coefficient and the rates of transformation. The relative affinity of CeO 2 NPs for bacterial suspensions in sludge appears to explain differences in the observed rates of Ce reduction for the two types of CeO 2 NPs studied. - Highlights: • We combine experimental and computational methods to track CeO 2 NPs through WWTPs. • We investigate the importance of environmental transformations on NP exposure. • We estimate the concentrations of CeO 2 NPs and reductive transformation byproducts. - CeO 2 nanoparticles that are released to the waste stream will preferentially associate with the solid phase (∼96%), where they will undergo significant transformation (∼50%)

  18. Novel nanostructured CeO2 as efficient catalyst for energy and ...

    Indian Academy of Sciences (India)

    CeO2 and CeO2 based hetero-nanocomposites for their suitability to important catalytic and energy-related applications. Keywords. CeO2; morphology; catalysis; soot oxidation; CO oxidation; ethanol electro-oxidation. 1. Introduction .... glycol)-poly(propylene glycol)-poly(ethylene glycol). (P123, Sigma-Aldrich) with a ...

  19. Homogeneously dispersed CeO2 nanoparticles on exfoliated hexaniobate nanosheets

    Science.gov (United States)

    Marques, Thalles M. F.; Strayer, Megan E.; Ghosh, Anupama; Silva, Alexandre; Ferreira, Odair P.; Fujisawa, Kazunori; Alves da Cunha, Jose R.; Abreu, Guilherme J. P.; Terrones, Mauricio; Mallouk, Thomas E.; Viana, Bartolomeu C.

    2017-12-01

    Hexaniobate nanosheets derived from the parent compound K4Nb6O17 have been decorated with CeO2 nanoparticles by ion exchange with aqueous cerium (IV) solution. Very homogeneous CeO2 nanoparticle decoration of the hexaniobate sheets can be achieved by this method and the resulting composites may absorb visible light. HRTEM images show that ∼3.0 nm diameter CeO2 nanoparticles adhere to hexaniobate nanosheets that are exfoliated and then restacked prior to Ce deposition. The interfacial interaction between CeO2 nanoparticles and nanosheets would be due to an electrostatic attraction mechanism. Raman and XRD measurements have given strong evidence that CeO2 nanoparticles have fluorite structure. EDS, FTIR and XPS results suggest almost complete exchange of TBA+ and K+ by Ce4+. Cerium ion exchange on the acid exchanged parent compound, H2.9K1.1Nb6O17, revealed that the extent of Ce ion exchange is much greater in case of nanosheets, which may be rationalized by the larger surface area available after exfoliation. XPS measurements show that the ratio of Ce4+/Ce3+ is around 4.4, in agreement with the formation of fluorite structure (CeO2). Thus, these CeO2 nanoparticle/nanosheet composites may be useful for catalytic processes.

  20. AstroNomical Information System at CeSAM

    Science.gov (United States)

    Gimenez, S.; Moreau, C.; Agneray, F.; Roehlly, Y.

    2014-05-01

    AstroNomical Information System (ANIS), developed by the Centre de donnéeS Astrophysique de Marseille (CeSAM), is a generic tool aimed at facilitating and homogenizing the implementation of astronomical data of various kinds and in dedicated Information Systems. ANIS provides high level services like: search, extract and display imaging and spectroscopic data using a combination of criteria, an object list, a sql query module or a cone search interfaces, as well as download of catalogs and complete datasets. With ANIS, the CeSAM offers web access to VO compliant Information Systems for different projects VVDS, HeDAM, ExoDat, HST-COSMOS, etc.), including ancillary data that are cross-matched before ingestion.

  1. Gamma-ray relative energy response of Ce: YAG crystal

    International Nuclear Information System (INIS)

    Zhang Jianhua; Zhang Chuanfei; Hu Mengchun; Peng Taiping; Wang Zhentong; Tang Dengpan; Zhao Guangjun

    2010-01-01

    Gamma-ray relative energy response of Ce: YAG crystal, which is important for pulsed γ-ray measurement, was studied in this work.The Ce: YAG crystal, which was developed at Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, was aligned point by point with γ-rays scattered from an industrial 60 Co line source. The γ-ray relative energy response was calculated using the mass attenuation coefficient. The results show that the numerical calculation method of γ-ray relative energy response is reliable, and the experimental method with multi-energy point γ-ray by Compton scattering is also feasible, that can be used for checking up correctness of the numerical calculation results. (authors)

  2. 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.

  3. Ru 4 ion in CeO 2 (Ce 0.95 Ru 0.05 O 2− ): A non-deactivating ...

    Indian Academy of Sciences (India)

    A new WGS catalyst, Ce1−RuO2− (0 ≤ ≤ 0.1) was prepared by hydrothermal method using melamine as a complexing agent. The Catalyst does not require any pre-treatment. Among the several compositions prepared and tested, Ce0.95Ru0.05O2− (5% Ru4+ ion substituted in CeO2) showed very high WGS ...

  4. 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

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

    OpenAIRE

    Xing, Xiaoping; Li, Dan

    2015-01-01

    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 ...

  6. Optical spectroscopy of the Ce-doped multicomponent garnets

    International Nuclear Information System (INIS)

    Canimoglu, A.; Karabulut, Y.; Ayvacikli, M.; Muresan, L.E.; Perhaita, I.; Barbu-Tudoran, L.; Garcia Guinea, J.; Karali, T.; Can, N.

    2016-01-01

    Here, we report our results referring to the preparation of Ce doped Y 2.22 MgGa 2 Al 2 SiO 12 , Y 1.93 MgAl 4 SiO 12 and Y 2.22 Gd 0.75 Ga 2 Al 3 O 12 using solid state reaction at high temperature. Several complementary methods (i.e. powder x-ray diffraction (XRPD), energy dispersive analysis of X-rays (EDX), scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR)) were studied to examine the effects of the synthesis procedure on the morphology and structure. XRD analyses revealed that all compounds include yttrium aluminate phase with garnet structure. Cathodoluminescence (CL), radioluminescence (RL) and photoluminescence (PL) measurements were carried out for clarification of relationship between host lattice defects and the spectral luminescence emissions. Luminescence emission of phosphors is peaked at 530 nm assigned to 5d-4f transitions of the dopant Ce 3+ ions with a broad emission band in 400–700 nm range. Under electron irradiation, the emission spectrum of Ce doped (YGd) 3 Ga 2 Al 3 O 12 is well defined and has a characteristic fairly narrow and sharp emission band peaking at 312 nm and 624 nm corresponding to transition of 6 P 7/2 → 8 S 7/2 and 6 G J → 6 P J (Gd 3+ ), respectively. We suggest some of phosphors might be excellent phototherapy phosphor materials under electron excitation. - Highlights: • Ce-doped Multicomponent Garnets were prepared solid state reaction method. • The shape and size of phosphor particles were examined. • The narrow band UV B emission due to Gd 3+ ions were observed.

  7. 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.

  8. CeDAMar global database of abyssal biological sampling

    OpenAIRE

    Stuart, Carol T.; Arbizu, Pedro Martinez; Smith, Craig R.; Molodtsova, Tina; Brandt, Angelika; Etter, Ron J.; Escobar-briones, Elva; Fabri, Marie-claire; Rex, Michael A.

    2008-01-01

    The Census of the Diversity of Abyssal Marine Life (CeDAMar), a division of the Census of Marine Life, has compiled the first comprehensive global database of biological samples taken in the abyssal plains of the world ocean. It is an essential resource for planning future exploration of the abyss, for synthesizing patterns of biogeography and biodiversity, and for environmentally safe exploitation of natural resources. The database is described in this article, and made available to investig...

  9. Qu'est-ce que l'Univers ?

    CERN Document Server

    2001-01-01

    Les plus grans spécialistes français sont réunis dans ce quatrième volume. Ils éclairent les grandes questions que pose la cosmologie, le Système solaire, les étoiles et les galaxies, la Terre, les océans et le climat, la matière et son organisation, l'évolution des mathématiques, la complexité, les transformations chimiques.

  10. Temperature-independent photoluminescence response in ZnO:Ce ...

    Indian Academy of Sciences (India)

    2017-12-06

    Dec 6, 2017 ... tion of rare-earth ions. Nowadays, rare-earth-doped ZnO semiconductor is an interesting field of study because of its unique optical properties and promising applications in optoelectronic devices [13–19]. Since cerium oxide (CeO2) has a band gap of ∼3 eV and shows interesting prop- erties similar to that ...

  11. Scintillation properties of the Ce-doped multicomponent garnetepitaxial films

    Czech Academy of Sciences Publication Activity Database

    Průša, Petr; Kučera, M.; Mareš, Jiří A.; Hanuš, M.; Beitlerová, Alena; Onderišinová, Z.; Nikl, Martin

    2013-01-01

    Roč. 35, č. 12 (2013), s. 2444-2448 ISSN 0925-3467 R&D Projects: GA ČR GAP204/12/0805 Institutional support: RVO:68378271 Keywords : scintillator * liquid phase epitaxy method * photoelectron yield * garnet * Ce 3+ Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.075, year: 2013 http://dx.doi.org/10.1016/j.optmat.2013.06.051

  12. Preparation and inhibition properties of molybdate intercalated ZnAlCe layered double hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Huajie; Wang, Jihui, E-mail: jhwang@tju.edu.cn; Zhang, Yu; Hu, Wenbin

    2016-09-05

    ZnAlCe layered double hydroxide intercalated by molybdate (ZnAlCe−MoO{sub 4} LDH) was successfully synthesized by using co-precipitation method, and the morphology, structure of ZnAlCe−MoO{sub 4} LDH were observed and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) techniques. The inhibition behavior of ZnAlCe−MoO{sub 4} LDH for Q235 steel in 3.5%NaCl solution was determined by polarization curves, electrochemical impedance spectroscopy (EIS), inductively coupled plasma mass spectrometer (ICP-MS) and X-ray photoelectron spectrometer (XPS) methods. The results shows that the synthesized ZnAlCe−MoO{sub 4} LDH has a lamellar structure with a particle size of 0.1–2.0 μm, an average thickness of 30 nm, and a basal plane spacing of 0.898 nm. Compared with the addition of ZnAl layered double hydroxide intercalated by nitrate (ZnAl−NO{sub 3} LDH) and ZnAl layered double hydroxide intercalated by molybdate (ZnAl−MoO{sub 4} LDH) in 3.5% NaCl solution, Q235 steel in 3.5%NaCl + ZnAlCe−MoO{sub 4} LDH solution has a lower corrosion current density, larger polarization resistance and a higher inhibition efficiency. The addition of ZnAlCe−MoO{sub 4} LDH will reduce the chloride concentration in 3.5% NaCl solution by the anion exchanged with molybdate, and improve the corrosion resistance of Q235 steel owing to the formation of passive film with the composition of ferrous or iron molybdate and deposition film with zinc and cerium hydroxides. - Highlights: • ZnAlCe−MoO{sub 4} LDH compound was successfully synthesized by co-precipitation method. • ZnAlCe−MoO{sub 4} LDH has a better inhibition effect to Q235 steel in 3.5%NaCl solution. • The Cl{sup −} ions in solution was partially exchanged with MoO{sub 4}{sup 2−} ions in host layers. • The passive film and deposition film were formed by the release of LDH compound.

  13. SZTUCZNE SUBSTANCJE SŁODZĄCE – WYSTĘPOWANIE W ŚRODOWISKU

    Directory of Open Access Journals (Sweden)

    Piotr REZKA

    2016-03-01

    Full Text Available W pracy przedstawiono zagadnienie występowania sztucznych substancji słodzących w ściekach oraz ich obecności w środowisku wodnym. Ze względu na zastosowanie w produkcji żywności i napojów o zmniejszonej wartości kalorycznej, związki te pojawiają się w ściekach w coraz większych ilościach. Najczęściej stosowanymi substytutami cukru jest acesulfam K, aspartam, cyklaminian sodu, sacharyna i sukraloza. Każda z tych substancji jest kilkadziesiąt razy bardziej słodka niż standardowy cukier (sacharoza, jednakże praktycznie nie podnoszą one wartości kalorycznej produktu. Dokonano przeglądu literatury, skupiając się na zawartościach rozpatrywanych substancji w ściekach surowych i oczyszczonych. Wykazano, że skuteczność eliminacji tych związków ze ścieków jest niewystarczająca i na skutek tego dochodzi do zanieczyszczenia środowiska wodnego. Przedstawiono w tabeli potwierdzone doniesienia dotyczące obecności tych związków w rzekach, jeziorach i wodach podziemnych. W przypadku gdy w wodzie ujmowanej przez stacje uzdatniania wody obecne są wyżej wymienione związki, w szczególności acesulfam i sukraloza, istnieje ryzyko przedostania się ich do wody przeznaczonej do spożycia, co znalazło potwierdzenie w literaturze. Mimo dostępnych wyników badań nie wykazujących wpływu na ekosystem i zdrowie człowieka, konieczne wydaje się przeprowadzenie badań nad wpływem długotrwałego narażenia organizmów wodnych i organizmu człowieka na działanie sztucznych substytutów cukru.

  14. 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.

  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. F-centre luminescence in nanocrystalline CeO2

    International Nuclear Information System (INIS)

    Aškrabić, S; Dohčević-Mitrović, Z D; Araújo, V D; Ionita, G; De Lima, M M Jr; Cantarero, A

    2013-01-01

    Nanocrystalline CeO 2 powders were synthesized by two cost-effective methods: the self-propagating room temperature (SPRT) method and the precipitation method. Differently prepared samples exhibited different temperature-dependent photoluminescence (PL) in the ultraviolet and visible regions. The PL signals originated from different kinds of oxygen-deficient defect centres with or without trapped electrons (F 0 , F + or F ++ centres). The temperature-dependent PL spectra were measured using different excitation lines, below (457, 488 and 514 nm) or comparable (325 nm) to the ceria optical band gap energy, in order to investigate the positions of intragap localized defect states. Evidence for the presence of F + centres was supported by the signals observed in electron paramagnetic resonance (EPR) measurements. Based on PL and EPR measurements it was shown that F + centres dominate in the CeO 2 sample synthesized by the SPRT method, whereas F 0 centres are the major defects in the CeO 2 sample synthesized by the precipitation method. The luminescence from F ++ states, as shallow trap states, was registered in both samples. Energy level positions of these defect states in the ceria band gap were proposed. (paper)

  17. F-centre luminescence in nanocrystalline CeO2

    Science.gov (United States)

    Aškrabić, S.; Dohčević-Mitrović, Z. D.; Araújo, V. D.; Ionita, G.; de Lima, M. M., Jr.; Cantarero, A.

    2013-12-01

    Nanocrystalline CeO2 powders were synthesized by two cost-effective methods: the self-propagating room temperature (SPRT) method and the precipitation method. Differently prepared samples exhibited different temperature-dependent photoluminescence (PL) in the ultraviolet and visible regions. The PL signals originated from different kinds of oxygen-deficient defect centres with or without trapped electrons (F0, F+ or F++ centres). The temperature-dependent PL spectra were measured using different excitation lines, below (457, 488 and 514 nm) or comparable (325 nm) to the ceria optical band gap energy, in order to investigate the positions of intragap localized defect states. Evidence for the presence of F+ centres was supported by the signals observed in electron paramagnetic resonance (EPR) measurements. Based on PL and EPR measurements it was shown that F+ centres dominate in the CeO2 sample synthesized by the SPRT method, whereas F0 centres are the major defects in the CeO2 sample synthesized by the precipitation method. The luminescence from F++ states, as shallow trap states, was registered in both samples. Energy level positions of these defect states in the ceria band gap were proposed.

  18. NMR study of CeTe at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Hinderer, J. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland)]. E-mail: hinderer@phys.ethz.ch; Weyeneth, S.M. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Weller, M. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Gavilano, J.L. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Felder, E. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Hulliger, F. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Ott, H.R. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland)

    2006-05-01

    We present {sup 125}Te NMR measurements on CeTe powder at temperatures between 1 and 150K and in magnetic fields between 5 and 8T. CeTe is a rocksalt-type intermetallic compound. It orders antiferromagnetically at T{sub N}{approx}2.2K 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 20K. Above T{sub N}, hyperfine fields of 1.6, 0.8 and 0.0T 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.

  19. Determination of the differences in oxidation potentials for the Pr3+/Pr2+ and Ce3+/Ce2+ pairs in halide melts

    International Nuclear Information System (INIS)

    Mikheev, N.B.; Auerman, L.N.; Rumer, I.A.; D'yachkova, R.A.

    1983-01-01

    Cocrystallization has been used with the (PrOCl)/sub s. ph/ - (PrCl 2 , PrCl 3 , SrCl 2 ) melt system to examine the dependence of the cerium(III) cocrystallization coefficient on the X/sub Pr 2+ /X/sub Pr 3+ / ratio in the melt. Measurement has been made in this way of the difference in oxidation potentials for the pairs Pr 3+ /Pr 2+ and Ce 3+ /Ce 2+ : ΔE/sub Pr 3+ /Pr 2+0 -E/sub Ce 3+ /Ce 2+ / 0 , which is 0.08 +/- 0.04 V for chloride

  20. Characteristics of CeCoIn5/Al/AlOx/Nb and CeCoIn5/Al/AlOx/Al tunnel junctions

    International Nuclear Information System (INIS)

    Nevirkovets, I.P.; Chernyashevskyy, O.; Petrovic, C.; Hu Rongwei; Ketterson, J.B.; Sarma, Bimal K.

    2009-01-01

    We report characteristics of CeCoIn 5 /Al/AlO x /Nb and CeCoIn 5 /Al/AlO x /Al tunnel junctions fabricated on the (0 0 1) surface of CeCoIn 5 crystal platelets. The main result of this work is the observation of a low Josephson current (as compared with that expected from the Ambegaokar-Baratoff formula), which is consistent with idea that the order parameter in the heavy-fermion superconductor CeCoIn 5 has unconventional pairing symmetry.

  1. 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.

  2. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Photocatalytic degradation of dye using CeO2/SCB composite catalysts

    Science.gov (United States)

    Channei, Duangdao; Nakaruk, Auppatham; Phanichphant, Sukon

    2017-08-01

    The main task of the present work is to enhance the photocatalytic degradation efficiency of methylene blue (MB) by using CeO2/sugarcane bagasse (SCB) composite catalysts. Homogeneous precipitation method was used to synthesis CeO2-SCB composite catalysts by adding SCB powder to precursor solution of Ce base-metal. The structural analytical data indicated the pure cubic fluorite structure of CeO2. Morphological images revealed the coating of CeO2 layer on high surface area of SCB core-shell. The chemical analysis presented spectrum of the Ce 3d in CeO2/SCB sample existed in the form of the Ce3 + and Ce4 + mixed- valence states. Optical spectra showed the shift of absorption edge towards longer visible region upon supporting CeO2 with SCB. The main chemical composition of the SCB was K, Ca, and Si. Furthermore, recombination of the photogenerated electrons and holes was identified by photoluminescence techniques (PL), the data suggested inhibition of electron-hole pairs recombination by the cations from SCB loaded in CeO2/SCB composite. Photocatalytic activity of CeO2/SCB catalyst was investigated via the degradation of MB under UV-A irradiation. Experimental kinetic data followed the pseudo-first order model. CeO2 supported with SCB adsorbent had higher photocatalytic activity in dye wastewater treatment compared to the pure CeO2. The proposed mechanism explaining the high photocatalytic efficiency of CeO2/SCB was associated with high surface properties and the suppression of recombination of the photogenerated electron-hole pairs by the SCB adsorbent.

  4. Microstructures and luminescent properties of Ce-doped transparent mica glass-ceramics

    International Nuclear Information System (INIS)

    Taruta, Seiichi; Iwasaki, Yoshitomo; Nishikiori, Hiromasa; Yamakami, Tomohiko; Yamaguchi, Tomohiro; Kitajima, Kunio; Okada, Kiyoshi

    2012-01-01

    Highlights: ► Ce-doped transparent glass-ceramics and their parent glasses. ► TEM and STEM images for the microstructures. ► Each mica crystal did not contain Ce uniformly. ► Emission due to Ce 3+ ions in the glass phase and/or Ce 3+ ions in the mica crystals. - Abstract: Transparent mica glass-ceramics were prepared by heating parent glasses that had been doped with 0.5–15 mol% CeO 2 . During the melting and heat treatment, Ce 4+ ions in the specimens were reduced to Ce 3+ ions, and one or both of these ion species were then replaced with Li + ions in the interlayers of the separated mica crystals. However, scanning transmission electron microscope (STEM) and Z-contrast imaging revealed that the mica crystals did not contain the same amount of Ce. On excitation at 254 nm, the parent glasses and glass-ceramics emitted blue light, which originated from the 5d to 4f transition of the Ce 3+ ions. The emission of the glass-ceramic containing a smaller amount of Ce was attributed to the Ce 3+ ions in both the glass phase and the mica crystals, whereas that of the glass-ceramics containing a larger amount of Ce was caused mainly by Ce 3+ ions in the mica crystals. The dependence of the emission band of the parent glasses on the amount of Ce was a unique feature of the Ce-doped transparent mica glass-ceramics and was not observed in previous studies of Eu-doped parent glasses and mica glass-ceramics.

  5. 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. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. 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.

  7. Touristes, tourismes : ce que des sciences sociales en disent (et ce que j’en pense.

    Directory of Open Access Journals (Sweden)

    Éric Boutouyrie

    2005-04-01

    Full Text Available Dernièrement, un ouvrage de l’équipe de géographes Mit (Équipe Mit , 2003 de l’Université de Paris 7 s’est fait l’écho d’un texte du philosophe et urbaniste Thierry Paquot publié en juillet 2001 dans le numéro 568 du Monde Diplomatique . Ce texte, intitulé « La tyrannie douce de l’air conditionné », se présentait comme une courte et dense réflexion sur le tourisme et le touriste. Les membres de l’Équipe Mit l’épinglent dans un chapitre consacré à ce ...

  8. CeBr3 as a room-temperature, high-resolution gamma-ray detector

    International Nuclear Information System (INIS)

    Guss, Paul; Reed, Michael; Yuan Ding; Reed, Alexis; Mukhopadhyay, Sanjoy

    2009-01-01

    Cerium bromide (CeBr 3 ) has become a material of interest in the race for high-resolution gamma-ray spectroscopy at room temperature. This investigation quantified the potential of CeBr 3 as a room-temperature, high-resolution gamma-ray detector. The performance of CeBr 3 crystals was compared to other scintillation crystals of similar dimensions and detection environments. Comparison of self-activity of CeBr 3 to cerium-doped lanthanum tribromide (LaBr 3 :Ce) was performed. Energy resolution and relative intrinsic efficiency were measured and are presented.

  9. The γ rays sensitivity measurement of CeF3 scintillator detector

    International Nuclear Information System (INIS)

    Hu Mengchun; Zhou Dianzhong; Li Rurong; Wang Zhentong; Yang Hongqiong; Zhang Jianhua; Hu Qingyuan; Peng Taiping

    2003-01-01

    The CeF 3 is an abio-scintillator developed in recent years, which are insensitive to neutron and sensitive to gamma rays and respond quickness. The relationship of CeF 3 scintillation detector gamma rays sensitivity with the change of crystal thickness was measured. The CeF 3 scintillation detector is composed by high liner current photomultiplier tube of CHφT3, CHφT5 and CeF 3 scintillator. The detector gamma rays sensitivity of purple photocell and common photocell with CeF 3 scintillator were measured too

  10. Controlled hydrothermal synthesis of CeO{sub 2} nanospheres and their excellent magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Xiaofei [Suzhou University, Anhui Key Laboratory of Spintronics and Nanomaterials Research, Suzhou, Anhui (China)

    2017-04-15

    Monodisperse spherical CeO{sub 2} nanostructures with irregular and rough surfaces have successfully been synthesized via a facile hydrothermal technology. XRD, SEM, XPS, Raman scattering, and M-H curves were employed to characterize the samples. The results showed that the spherical CeO{sub 2} nanostructures have a cubic fluorite structure and that there are Ce{sup 3+} ions and oxygen vacancies in the surface of the samples. The M-H curve of CeO{sub 2} nanospheres exhibits excellent room-temperature ferromagnetism (RT-FM), which is likely ascribed to the effects of the Ce{sup 3+} ions and oxygen vacancies. (orig.)

  11. Controlled hydrothermal synthesis of CeO2 nanospheres and their excellent magnetic properties

    Science.gov (United States)

    Niu, Xiaofei

    2017-04-01

    Monodisperse spherical CeO2 nanostructures with irregular and rough surfaces have successfully been synthesized via a facile hydrothermal technology. XRD, SEM, XPS, Raman scattering, and M-H curves were employed to characterize the samples. The results showed that the spherical CeO2 nanostructures have a cubic fluorite structure and that there are Ce3+ ions and oxygen vacancies in the surface of the samples. The M-H curve of CeO2 nanospheres exhibits excellent room-temperature ferromagnetism (RT-FM), which is likely ascribed to the effects of the Ce3+ ions and oxygen vacancies.

  12. The stable Ce.sup.4+./sup. center: a new tool to optimize Ce-doped oxide scintillators

    Czech Academy of Sciences Publication Activity Database

    Nikl, Martin; Babin, Vladimir; Pejchal, Jan; Laguta, Valentyn; Buryi, Maksym; Mareš, Jiří A.; Kamada, K.; Kurosawa, S.; Yoshikawa, A.; Pánek, D.; Parkman, T.; Brůža, Petr; Mann, K.; Müller, M.

    2016-01-01

    Roč. 63, č. 2 (2016), s. 433-438 ISSN 0018-9499 R&D Projects: GA ČR GJ15-18300Y; GA MŠk(CZ) LG13029 Institutional support: RVO:68378271 Keywords : Ce 4+ * gamma-ray detection * LuAG * scintillator * X-ray detection Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.171, year: 2016

  13. Nanocrystalline Mn-Mo-Ce Oxide Anode Doped Rare Earth Ce and Its Selective Electro-catalytic Performance

    Directory of Open Access Journals (Sweden)

    SHI Yan-hua

    2017-09-01

    Full Text Available The anode oxide of nanocrystalline Mn-Mo-Ce was prepared by anode electro-deposition technology, and its nanostructure and selective electro-catalytic performance were investigated using the SEM, EDS, XRD, HRTEM, electrochemical technology and oxygen evolution efficiency testing. Furthermore, the selective electro-catalytic mechanism of oxygen evolution and chlorine depression was discussed. The results show that the mesh-like nanostructure Mn-Mo-Ce oxide anode with little cerium doped is obtained, and the oxygen evolution efficiency for the anode in the seawater is 99.51%, which means a high efficiency for the selective electro-catalytic for the oxygen evolution. Due to the structural characteristics of γ-MnO2, the OH- ion is preferentially absorbed, while Cl- absorption is depressed. OH- accomplishes the oxygen evolution process during the valence transition electrocatalysis of Mn4+/Mn3+, completing the selective electro-catalysis process. Ce doping greatly increases the reaction activity, and promotes the absorption and discharge; the rising interplanar spacing between active (100 crystalline plane promotes OH- motion and the escape of newborn O2, so that the selective electro-catalytic property with high efficient oxygen evolution and chlorine depression is achieved from the nano morphology effect.

  14. Tetragonal Ce-based Ce-Sm(Fe, Co, Ti){sub 12} alloys for permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Cid, Andres; Salazar, Daniel [BCMaterials, Bizkaia Science and Tecnology Park, 48160 Derio (Spain); Gabay, Aleksandr M.; Hadjipanayis, George C. [Department of Physics and Astronomy, University of Delaware, Newark, DE, 19716 (United States); Barandiaran, Jose Manuel [BCMaterials, Bizkaia Science and Tecnology Park, 48160 Derio (Spain); Department of Electricity and Electronics, University Basque Country (UPV/EHU), 48080 Bilbao (Spain)

    2016-12-15

    Abundance and relatively low cost of Ce provide a great incentive for its use in rare-earth permanent magnets. It has been recently reported that the tetragonal Ce(Fe,Co,Ti)12 compounds may exhibit application-worthy intrinsic magnetic properties. In this work the effect of the α-Fe phase formation due to the evaporation of Sm during alloy fabrication has been studied, as a previous step in the attempt to convert the intrinsic magnetic properties into functional properties of a permanent magnet. Ce{sub 0.5}Sm{sub 0.5}Fe{sub 9}Co{sub 2}Ti alloys based on the ThMn12-type crystal structure have been synthesized via melt-spinning with different Sm content. Coercive fields between 2.8 and 1.4 kOe have been found for α-Fe phase contents between 8 and 46% in volume, showing the influence of the α-Fe phase on the coercivity and exchange coupling between the hard and soft phase. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Numerical simulation of the geometrical-optics reduction of CE2 and comparisons to quasilinear dynamics

    Science.gov (United States)

    Parker, Jeffrey B.

    2018-05-01

    Zonal flows have been observed to appear spontaneously from turbulence in a number of physical settings. A complete theory for their behavior is still lacking. Recently, a number of studies have investigated the dynamics of zonal flows using quasilinear (QL) theories and the statistical framework of a second-order cumulant expansion (CE2). A geometrical-optics (GO) reduction of CE2, derived under an assumption of separation of scales between the fluctuations and the zonal flow, is studied here numerically. The reduced model, CE2-GO, has a similar phase-space mathematical structure to the traditional wave-kinetic equation, but that wave-kinetic equation has been shown to fail to preserve enstrophy conservation and to exhibit an ultraviolet catastrophe. CE2-GO, in contrast, preserves nonlinear conservation of both energy and enstrophy. We show here how to retain these conservation properties in a pseudospectral simulation of CE2-GO. We then present nonlinear simulations of CE2-GO and compare with direct simulations of quasilinear (QL) dynamics. We find that CE2-GO retains some similarities to QL. The partitioning of energy that resides in the zonal flow is in good quantitative agreement between CE2-GO and QL. On the other hand, the length scale of the zonal flow does not follow the same qualitative trend in the two models. Overall, these simulations indicate that CE2-GO provides a simpler and more tractable statistical paradigm than CE2, but CE2-GO is missing important physics.

  16. 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.

  17. Luminescent and scintillation properties of the Ce3+ doped Y3−xLuxAl5O12:Ce single crystalline films

    International Nuclear Information System (INIS)

    Zorenko, Yu.; Gorbenko, V.; Zorenko, T.; Popielarski, P.; Mosińska, L.; Fedorov, A.

    2016-01-01

    The work is related to the investigation of scintillation and luminescent properties of single crystalline films (SCF) of solid solutions of Ce 3+ doped Y 3−x Lu x Al 5 O 12 :Ce garnets with x value in the 0–3 range. We have shown a possibility of realization of high-energy shift of the Ce 3+ ion emission spectrum in these garnets up to 22 nm. We have also found that the light yield of the radioluminescence under α-particle excitation of LuAG:Ce SCF can exceed by 1.3 times the corresponding values for the YAG:Ce SCF counterpart. For investigation of the luminescent properties of Y 3−x Lu x Al 5 O 12 :Ce SCF at different x values the luminescent spectroscopy of these SCFs under excitation by synchrotron radiation in the VUV range was performed. - Highlights: • Single crystalline films of Y 3−x Lu x Al 5 O 12 garnets at x=0–3.0 were grown by LPE method onto YAG substrates. • Lattice constant of Y 3−x Lu x Al 5 O 12 :Ce film and the film/substrate misfit changed linearly with increasing of Lu content in the x=0–3.0 range. • High-energy shift of the Ce 3+ emission up to 22 nm in Y 3−x Lu x Al 5 O 12 film with increasing of Lu content in the x=0–3.0 range. • Light yield of Y 3−x Lu x Al 5 O 12 :Ce film decreases in the x=0–1.8 range and increases in the x=1.8–3.0 range. • Scintillation LY of Lu 3 Al 5 O 12 :Ce film can exceed by 1.3 times the LY for YAG:Ce film counterpart.

  18. Study of Ce-Cu mixed oxide catalysts by in situ electrical conductivity measurements.

    Science.gov (United States)

    Popescu, Ionel; Piumetti, Marco; Bensaid, Samir; Marcu, Ioan-Cezar

    2017-12-06

    Three Ce-Cu mixed oxides, namely Ce 0.95 Cu 0.05 , Ce 0.6 Cu 0.4 and Ce 0.15 Cu 0.85 , along with pure CeO 2 and CuO were characterized by in situ electrical conductivity measurements. Their electrical conductivity was studied as a function of temperature and oxygen partial pressure, and was followed with time during successive exposure to air, nitrogen and different gaseous mixtures containing propane as a VOC model molecule, under conditions close to those of their catalytic applications. CeO 2 and CuO appeared to be n-type and p-type semiconductors, respectively, while the semiconducting behavior of the Ce-Cu mixed oxides depended on the oxide composition. The semiconductive and redox properties of the samples were correlated with their catalytic behavior in CO oxidation, ethene total oxidation and soot combustion.

  19. Method for removing trace contaminants from multicurie amounts of 144Ce

    International Nuclear Information System (INIS)

    Wagner, J.A.; Kanapilly, G.M.

    1976-01-01

    Removal of contaminants from stock solutions of 144 Ce(III) was required for large quantities of 144 Ce prior to incorporation into fused aluminosilicate particles for inhalation toxicology studies. Since available procedures for purification of 144 Ce could not be readily adapted to our laboratory conditions and requirements, a simple procedure was developed to purify 144 Ce in multicurie quantities of 144 Ce(III). This procedure consists of separation of 144 Ce from contaminants by precipitation and filtrations at different pH. Its simplicity and efficacy in providing a stock solution that would readily exchange into montmorillonite clay was demonstrated when it was used during the preparation of large amounts of 144 Ce in fused aluminosilicate particles

  20. Facile preparation of self-healing superhydrophobic CeO2 surface by electrochemical processes

    Science.gov (United States)

    Nakayama, Katsutoshi; Hiraga, Takuya; Zhu, Chunyu; Tsuji, Etsushi; Aoki, Yoshitaka; Habazaki, Hiroki

    2017-11-01

    Herein we report simple electrochemical processes to fabricate a self-healing superhydrophobic CeO2 coating on Type 304 stainless steel. The CeO2 surface anodically deposited on flat stainless steel surface is hydrophilic, although high temperature-sintered and sputter-deposited CeO2 surface was reported to be hydrophobic. The anodically deposited hydrophilic CeO2 surface is transformed to hydrophobic during air exposure. Specific accumulation of contaminant hydrocarbon on the CeO2 surface is responsible for the transformation to hydrophobic state. The deposition of CeO2 on hierarchically rough stainless steel surface produces superhydrophobic CeO2 surface, which also shows self-healing ability; the surface changes to superhydrophilic after oxygen plasma treatment but superhydrophobic state is recovered repeatedly by air exposure. This work provides a facile method for preparing a self-healing superhydrophobic surface using practical electrochemical processes.

  1. Manganese/cerium clusters spanning a range of oxidation levels and CeMn(8), Ce(2)Mn(4), and Ce(6)Mn(4) nuclearities: structural, magnetic, and EPR properties.

    Science.gov (United States)

    Lampropoulos, Christos; Thuijs, Annaliese E; Mitchell, Kylie J; Abboud, Khalil A; Christou, George

    2014-07-07

    The syntheses, structures, and magnetic properties are reported for three new Ce/Mn clusters with different Ce/Mn ratios: [Ce6Mn4O12(O2CMe)10(NO3)4(py)4] (py = pyridine) (1), [CeMn8O8(O2CCH2(t)Bu)12(DMF)14] (DMF = dimethylformamide) (2), and [Ce2Mn4O2(O2CMe)6(NO3)4(hmp)4] (3; hmp(-) is the anion of 2-(hydroxymethyl)pyridine). 1 and 2 were obtained from the reaction of Ce(IV) with [Mn12O12(O2CMe)16(H2O)4] (Mn(III)8Mn(IV)4) and [Mn8O2(O2CCH2(t)Bu)14((t)BuCH2CO2H)4] (Mn(II)6Mn(III)2), respectively, whereas 3 resulted from the oxidation of Mn(II) acetate with Ce(IV) in the presence of hmpH. Cluster 1 possesses an unusual [Ce6Mn4O12](14+) core topology consisting of a [Ce6O8] face-capped octahedron, which is face-fused at each end to a [Ce(IV)2Mn(III)Mn(IV)O4] cubane. Cluster 2 possesses a nonplanar, saddlelike loop of eight Mn(III) atoms bridged by eight μ3-O(2-) ions to a central Ce(IV) atom. Cluster 3 is similar to 1 in possessing an octahedral core, but this is now a [Ce2Mn4] octahedron consisting of a Ce(III) atom on either side of a Mn4 parallelogram, with the metal atoms bridged by two μ4-O(2-) ions, the alkoxide arms of four hmp(-) groups, and six acetates. Clusters 1, 2, and 3 are thus at the Ce(IV)6Mn(III)2Mn(IV)2, Ce(IV)Mn(III)8, and Ce(III)2Mn(III)4 oxidation levels, respectively. Variable-temperature, solid-state direct current (DC) and alternating current (AC) magnetization studies on 1-3 in the 5.0-300 K range revealed predominantly antiferromagnetic exchange interactions within the complexes. For 1, fitting of the DC data to the theoretical expression for a dinuclear Mn(III)Mn(IV) complex derived using the Van Vleck equation and an isotropic spin Hamiltonian (ℋ = -2JŜi·Ŝj convention) gave a value for the exchange coupling parameter (J) of -60.4(7) cm(-1) and a Landé factor g = 2.00(1), indicating an S = 1/2 ground state. For 2, both DC and AC data indicate an S = 0 ground state, which is unprecedented for a member of the CeMn8 family and now

  2. Measurement of Ce(IV) Concentration in Foam Decontaminant containing Fluorosurfactant

    International Nuclear Information System (INIS)

    Jung, Chong Hun; Yang, H. B.; Yoon, I. H.; Choi, W. K.; Moon, J. K.; Lee, J. S.

    2016-01-01

    To improve the stability of the foam, surfactants and inorganic materials such as nanoparticles can be added. A nanoparticle-based foam decontaminant is composed of a surfactant and nanoparticles for the generation and maintenance of foam, and a chemical decontamination agent made of Ce(IV) dissolved in nitric acid. Ce(IV) will be reduced to Ce(III) through the decontamination process. Oxidizing the cerium (III) can be reused as a decontamination agent, Ce(IV). Oxidation treatment technology by ozone uses its strong oxidizing power. It can be regarded as an environmentally friendly process, because ozone cannot be stored and transported like other industrial gases (because it quickly decays into diatomic oxygen) and must therefore be produced on site, and used ozone can be decomposed immediately. A concentration analysis of Ce(IV) in foam decontaminant containing a surfactant is necessary prior to the derivation of optimal conditions for the regeneration of Ce(III) through ozonation treatment. A UV spectrometric method using the absorbance or potentiometric method with a potential difference in Ce(III)/Ce(IV), or a potentiometric titration method using Fe (II), can be used for a Ce(IV) concentration analysis. A UV spectrometric method has a problem receiving the influence of the surfactant, and a potentiometric method is difficult to use because of the problem of an insignificant change in the potential difference value of the Ce(III)/Ce(IV). Thus, the present study was undertaken to determine whether the potentiometric titration method can be used for an analysis of the Ce(IV) concentration in the nanoparticle-based foam decontaminant containing surfactant. It will be effectively used for the Ce(IV) concentration measurement, in relation to the subsequent research on the derivation of optimal conditions for the regeneration of Ce(III) through ozonation treatment.

  3. Measurement of Ce(IV) Concentration in Foam Decontaminant containing Fluorosurfactant

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Chong Hun; Yang, H. B.; Yoon, I. H.; Choi, W. K.; Moon, J. K. [KAERI, Daejeon (Korea, Republic of); Lee, J. S. [Gachon University, Seongnam (Korea, Republic of)

    2016-05-15

    To improve the stability of the foam, surfactants and inorganic materials such as nanoparticles can be added. A nanoparticle-based foam decontaminant is composed of a surfactant and nanoparticles for the generation and maintenance of foam, and a chemical decontamination agent made of Ce(IV) dissolved in nitric acid. Ce(IV) will be reduced to Ce(III) through the decontamination process. Oxidizing the cerium (III) can be reused as a decontamination agent, Ce(IV). Oxidation treatment technology by ozone uses its strong oxidizing power. It can be regarded as an environmentally friendly process, because ozone cannot be stored and transported like other industrial gases (because it quickly decays into diatomic oxygen) and must therefore be produced on site, and used ozone can be decomposed immediately. A concentration analysis of Ce(IV) in foam decontaminant containing a surfactant is necessary prior to the derivation of optimal conditions for the regeneration of Ce(III) through ozonation treatment. A UV spectrometric method using the absorbance or potentiometric method with a potential difference in Ce(III)/Ce(IV), or a potentiometric titration method using Fe (II), can be used for a Ce(IV) concentration analysis. A UV spectrometric method has a problem receiving the influence of the surfactant, and a potentiometric method is difficult to use because of the problem of an insignificant change in the potential difference value of the Ce(III)/Ce(IV). Thus, the present study was undertaken to determine whether the potentiometric titration method can be used for an analysis of the Ce(IV) concentration in the nanoparticle-based foam decontaminant containing surfactant. It will be effectively used for the Ce(IV) concentration measurement, in relation to the subsequent research on the derivation of optimal conditions for the regeneration of Ce(III) through ozonation treatment.

  4. 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.

  5. Ultraviolet and near-infrared luminescence of LaBO3:Ce3+,Yb3+

    Science.gov (United States)

    Wei, Heng-Wei; Shao, Li-Ming; Jiao, Huan; Jing, Xi-Ping

    2018-01-01

    Ce3+ or Yb3+ singly doped LaBO3 and Ce3+-Yb3+ co-doped LaBO3 were prepared by conventional solid state reactions at 1100 °C and their photoluminescence (PL) properties were investigated. The emission spectrum of LaBO3:Ce3+,Yb3+ contains both the Ce3+ ultraviolet (UV) emissions (355 nm and 380 nm) and the Yb3+ near infrared (NIR) emission (975 nm) when excited by the UV light at 270 nm. By using the data of the Ce3+ decay curves and the PL intensities of both Ce3+ and Yb3+, the energy transfer efficiency (η) from Ce3+ to Yb3+, the actual energy transfer efficiency (AE) and the quantum efficiency (Q) of the Yb3+ emission were calculated. In the Ce3+-Yb3+ co-doped LaBO3, Ce3+ can transfer its absorbed energy to Yb3+ efficiently (η can be over 60%), and Yb3+ shows the Q value over 50% when it accepts the energy from Ce3+, which results in the low AE value ∼30%. The energy transfer process from Ce3+ to Yb3+ may be understood by the charge transfer mechanism: Ce3+ + Yb3+ ↔ Ce4+ + Yb2+. Particularly the Ce3+-Yb3+ co-doped LaBO3 phosphor gives the emissions mainly in the UV range and the NIR range with a portion of visible emissions in eye-insensitive range. This unique property may be suitable for applications in anti-counterfeiting techniques and public security affairs.

  6. 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

  7. Effects of Ce3+ concentration, beam voltage and current on the cathodoluminescence intensity of SiO2: Pr3+–Ce3+ nanophosphor

    CSIR Research Space (South Africa)

    Mhlongo, GH

    2011-02-01

    Full Text Available SiO2:Pr3+–Ce3+ phosphor powders were successfully prepared using a sol–gel process. The concentration of Pr3+ was fixed at 0.2 mol% while that of Ce3+ was varied in the range of 0.2–2 mol%. High resolution transmission electron microscopy (HRTEM...

  8. Abnormal variation of magnetic properties with Ce content in (PrNdCe)2Fe14B sintered magnets prepared by dual alloy method

    Science.gov (United States)

    Xue-Feng, Zhang; Jian-Ting, Lan; Zhu-Bai, Li; Yan-Li, Liu; Le-Le, Zhang; Yong-Feng, Li; Qian, Zhao

    2016-05-01

    Resource-saving (PrNdCe)2Fe14B sintered magnets with nominal composition (PrNd)15-x Ce x Fe77B8 (x = 0-10) were prepared using a dual alloy method by mixing (PrNd)5Ce10Fe77B8 with (PrNd)15Fe77B8 powders. For Ce atomic percent of 1% and 2%, coercivity decreases dramatically. With further increase of Ce atomic percent, the coercivity increases, peaks at 6.38 kOe in (PrNd)11Ce4Fe77B8, and then declines gradually. The abnormal dependence of coercivity is likely related to the inhomogeneity of rare earth chemical composition in the intergranular phase, where PrNd concentration is strongly dependent on the additive amount of (PrNd)5Ce10Fe77B8 powders. In addition, for Ce atomic percent of 8%, 7%, and 6% the coercivity is higher than that of magnets prepared by the conventional method, which shows the advantage of the dual alloy method in preparing high abundant rare earth magnets. Project supported by the National Natural Science Foundation of China (Grant Nos. 51461033, 51571126, 51541105, and 11547032), the Natural Science Foundation of Inner Mongolia, China (Grant No. 2013MS0110), and the Inner Mongolia University of Science and Technology Innovation Fund, China.

  9. H2 production through steam reforming of ethanol over Pt/ZrO2, Pt/CeO2 and Pt/CeZrO2 catalysts

    OpenAIRE

    Noronha, Fábio Bellot; Silva, Adriana Maria da; Lima, Sonia M. de; Mattos, Lisiane Veiga; Cruz, Ivna O. da; Jacobs, Gary; Davis, Burtron H

    2008-01-01

    The effect of the support nature and metal dispersion on the performance of Pt catalysts during steam reforming of ethanol was studied. H2 and CO production was facilitated over Pt/CeO2 and Pt/CeZrO2, whereas the acetaldehyde and ethene formation was favored on Pt/ZrO2.

  10. 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)

  11. Ból gardła – kiedy leczenie objawowe jest wystarczające?

    Directory of Open Access Journals (Sweden)

    Bolesław Kalicki

    2012-07-01

    Full Text Available Ból gardła należy do najczęstszych przyczyn porad lekarskich. Przyczyną bólu gardła jest zazwyczaj stan zapalny rozwijający się na podłożu infekcyjnym. Zapalenia gardła i migdałków w 70‑85% u dzieci i w 90‑95% u dorosłych spowodowane są zakażeniami wirusowymi. Najczęściej są to rinowirusy, koronawirusy, adenowirusy, wirusy Epsteina‑Barr, Coxsackie, herpes simplex oraz wirusy grypy i paragrypy. Bakteryjne zapa‑ lenia gardła zwykle wywoływane są przez paciorkowce beta‑hemolizujące grupy A, głównie Streptococcus pyogenes. Niezależnie od etiologii do zakażenia dochodzi drogą kropelkową oraz przez kontakt z wydzieliną nosogardła osoby chorej. Diagnostyka bólu gardła opiera się na danych z dokładnie zebranego wywiadu oraz badania przedmiotowego. Czasami niezbędne jest wykonanie szybkiego testu w kierunku streptokoków lub badań laboratoryjnych. Odróżnienie zakażeń bakteryjnych od wirusowych ma istotne znaczenie ze względu na narastającą antybiotykooporność i ogólnoświatową tendencję do nadużywania antybiotyków. W pierwszej kolejności należy zastosować leczenie objawowe, wskazane jest stosowanie leków przeciwzapalnych, przeciw‑ bólowych oraz leczenie miejscowe z zastosowaniem substancji przeciwbólowych i zmniejszających stan zapal‑ ny (chlorowodorek benzydaminy, flurbiprofen, salicylan choliny, chlorchinaldol. W przypadku etiologii bak‑ teryjnej antybiotykiem pierwszego rzutu jest fenoksymetylopenicylina, alternatywnie cefalosporyna I generacji lub amoksycylina, zaś w przypadku reakcji uczuleniowych na powyższe antybiotyki – makrolidy.

  12. Nanostructured Lanthanum Halides and CeBr3 for Nuclear Radiation and Detection

    International Nuclear Information System (INIS)

    Guss, Paul; Mukhopadhyay, Sanjoy; Guise, Ron; Yuan, Ding

    2010-01-01

    Scintillator materials are used to detect, and in some cases identify, gamma rays. Higher performance scintillators are expensive, hard to manufacture, fragile, and sometimes require liquid nitrogen or cooling engines. But whereas lower-quality scintillators are cheap, easy to manufacture, and more rugged, their performance is lower. At issue: can the desirable qualities of high-and low-performance scintillators be combined to achieve better performance at lower cost? Preliminary experiments show that a LaF 3 :Ce oleic acid-based nanocomposite exhibits a photopeak when exposed to 137 Cs source gamma-radiation. The chemical synthesis of the cerium-doped lanthanum halide nanoparticles are scalable and large quantities of material can be produced at a time, unlike typical crystal growth processes such as the Bridgeman process. Using a polymer composite (Figure 1), produced by LANL, initial measurements of the unloaded and 8% LaF 3 :Ce-loaded sample have been made using 137 Cs sources. Figure 2 shows an energy spectrum acquired for CeF 3 . The lighter plot is the measured polymer-only spectrum and the black plot is the spectrum from the nanocomposite scintillator. As the development of this material continues, the energy resolution is expected to improve and the photopeak-to-Compton ratio will become greater at higher loadings. These measurements show the expected Compton edge in the polymer-only sample, and the Compton edge and photo-peak expected in the nanophosphor composites that LANL has produced. Using a porous VYCORR with CdSe/ZnS core shell quantum dots, Letant has demonstrated that he has obtained signatures of the 241Am photopeak with energy resolution as good at NaI (Figure 3). We begin with the fact that CeBr 3 crystals do not have a self-activity component as strong as the lanthanum halides. The radioactive 0.090% 138 La component of lanthanum leads to significant self-activity, which will be a problem for very large detector volumes. Yet a significant

  13. 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.

  14. 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

    if results on a several-fold activity increase of a series of Pt/rare-earth alloys hold also for Pd rare-earth alloys. Pd5Ce crystallizes in two phases, a so-called low-temperature phase, L-Pd5Ce, which has a cubic symmetry, and a high-temperature phase, H-Pd5Ce, with a hexagonal symmetry. In both cases......, in agreement with DFT results for the L-Pd5Ce phase. Although we did not discover a new promising Pd-based catalyst, we have shown that the activity for oxygen reduction is strongly influenced by the alloy crystal structure. Furthermore, we have qualitatively demonstrated that transformation from H-Pd5Ce to L...

  15. Flux synthesis, modulated crystal structures, and physical properties of REMn0.5SeO (RE = La, Ce)

    International Nuclear Information System (INIS)

    Peschke, Simon; Johrendt, Dirk; Nitsche, Fabian

    2015-01-01

    The selenide oxides REMn 0.5 SeO (RE = La, Ce) were synthesized by heating RE 2 O 3 , RE, Mn, and Se in a NaI/KI flux at 800 C, and their modulated crystal structures determined by X-ray single crystal and powder diffraction {P 1 1 2/n(αβ1/2)0s, Z = 2, LaMn 0.5 SeO: a = 405.7(1), b = 405.7(1), c = 915.2(1) pm, γ = 90 , q = [1/10, -1/10, 1/2]; CeMn 0.5 SeO: a = 402.0(1), b = 401.8(1), c = 910.7(1) pm, γ = 90.000(4) , q = [0.0789(2), -0.0783(2), 1/2]}. The structures are related to the ZrCuSiAs-type structure with ordered vacancies at the manganese sites. The resulting modulations of the checkerboard pattern in the [Mn 0.5 Se] layers can be approximated by 10a x 10b x 2c and 51a x 51b x 2c supercells in LaMn 0.5 SeO and CeMn 0.5 SeO, respectively. Both compounds are insulators. The optical bandgap of LaMn 0.5 SeO was determined to 2.13 eV from the Kubelka-Munk function. Magnetic measurements indicate antiferromagnetic ordering of the Mn 2+ moments with Neel points well above room temperature, as known from related manganese compounds. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Alantoina – właściwości gojące i przeciwzapalne

    Directory of Open Access Journals (Sweden)

    Elżbieta Szymańska

    2012-04-01

    Full Text Available Alantoina jest pochodną mocznika wykazującą działanie keratolityczne poprzez oddziaływanie na desmoso‑ my, które stanowią połączenia pomiędzy korneocytami. Dzięki takiemu działaniu alantoina pozwala pozbyć się nadmiaru zrogowaciałego naskórka. Równocześnie poprzez stymulowanie podziałów komórkowych i epiteli‑ zacji przyspiesza odnowę uszkodzonego procesem zapalnym naskórka. Alantoina dodatkowo ma właściwości silnie nawilżające oraz wykazuje wysokie bezpieczeństwo terapii – nie alergizuje, nie powoduje podrażnienia skóry. Ze względu na wymienione właściwości alantoina ma szerokie zastosowanie w kosmetyce i farmacji. Jest składnikiem wielu preparatów przeznaczonych dla skóry suchej, trądzikowej lub alergicznej. Ponadto jest czę‑ stym składnikiem preparatów po opalaniu, dezodorantów, szamponów, płynów do kąpieli i przede wszystkim miejscowych leków dermatologicznych. Alantoina zawarta w maści czy kremie przyspiesza proces złuszcze‑ nia się martwych komórek naskórka, sprawiając, że skóra staje się gładsza. Dzięki właściwościom przyspiesza‑ jącym proliferację komórek nabłonka alantoina przyspiesza odbudowę naskórka, dzięki czemu skóra znacznie łatwiej zachowuje większą ilość wody oraz odbudowuje ochronny płaszcz hydrolipidowy, ustępują także dokucz‑ liwe subiektywne objawy towarzyszące suchości skóry, przede wszystkim uczucie napięcia i pieczenia. Prepara‑ ty zawierające alantoinę polecane są również wspomagająco w terapii chorób skóry przebiegających z zaburze‑ niem rogowacenia lub uszkodzeniem naskórka, takich jak atopowe zapalenie skóry, wyprysk kontaktowy, łuszczyca, rybia łuska, owrzodzenia czy oparzenia. Uzupełniająca terapia zewnętrzna preparatami zawierają‑ cymi alantoinę znacznie łagodzi objawy chorobowe i tym samym poprawia komfort życia pacjenta.

  17. Fast humidity sensors based on CeO2 nanowires

    International Nuclear Information System (INIS)

    Fu, X Q; Wang, C; Yu, H C; Wang, Y G; Wang, T H

    2007-01-01

    Fast humidity sensors are reported that are based on CeO 2 nanowires synthesized by a hydrothermal method. Both the response and recovery time are about 3 s, and are independent of the humidity. The sensitivity increases gradually as the humidity increases, and is up to 85 at 97% RH. The resistance decreases exponentially with increasing humidity, implying ion-type conductivity as the humidity sensing mechanism. A model based on the morphology and surface energy of the nanowires is given to explain these results further. Our experimental results indicate a pathway to improving the performance of humidity sensors

  18. espèce de tilapia Sarotherodon melanotheron melanothero

    African Journals Online (AJOL)

    Sci-Nat

    melanotheron, objet du présent travail, dont l'aire de répartition s'étend de la Côte d'Ivoire au. Cameroun. En Côte d'Ivoire, ce poisson se rencontre dans les estuaires et eaux saumâtres, depuis le fleuve Cavally (à l'Ouest) à la lagune. Aby (à l'Est) mais aussi en amont du lac de barrage du fleuve Bia (Gourène et al., 1999).

  19. Decay pattern of the Pygmy Dipole Resonance in 140Ce

    Directory of Open Access Journals (Sweden)

    Isaak J.

    2015-01-01

    Full Text Available The decay behavior of low-lying dipole states in 140Ce was investigated exploiting the γ3-setup at the HIγS facility using quasi-monochromatic photon beams. Branching ratios of individual excited states as well as average branching ratios to low-lying states have been extracted using γ – γ coincidence measurements. The comparison of the average branching ratios to QPM calculations shows a remarkable agreement between experiment and theory in the energy range from 5.0 to 8.5 MeV.

  20. Is Auger-free luminescence present in CeF₃?

    OpenAIRE

    Itoh, Minoru; Iri, Daisuke; Kitaura, Mamoru

    2009-01-01

    It is well known that Auger-free luminescence (AFL) is observable when the condition E-g>E-vc is satisfied, where E-g is the band-gap energy between the lowest unoccupied band and the highest occupied band and E-vc the energy difference between the top of the highest occupied band and the top of the next lower occupied band. From measurements of reflection and X-ray photoelectron spectra, CeF₃ is demonstrated to really satisfy this condition. No evidence for AFL is found, nevertheless. The ab...

  1. 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

  2. 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. Copyright © 2014. Published by Elsevier Ltd.

  3. Scientific Objectives of China Chang E 4 CE-4 Lunar Far-side Exploration Mission

    Science.gov (United States)

    Zhang, Hongbo; Zeng, Xingguo; Chen, Wangli

    2017-10-01

    China has achieved great success in the recently CE-1~CE-3 lunar missions, and in the year of 2018, China Lunar Exploration Program (CLEP) is going to launch the CE-4 mission. CE-4 satellite is the backup satellite of CE-3, so that it also consists of a Lander and a Rover. However, CE-4 is the first mission designed to detect the far side of the Moon in human lunar exploration history. So the biggest difference between CE-4 and CE-3 is that it will be equipped with a relay satellite in Earth-Moon-L2 Point for Earth-Moon Communication. And the scientific payloads carried on the Lander and Rover will also be different. It has been announced by the Chinese government that CE-4 mission will be equipped with some new international cooperated scientific payloads, such as the Low Frequency Radio Detector from Holland, Lunar Neutron and Radiation Dose Detector from Germany, Neutral Atom Detector from Sweden, and Lunar Miniature Optical Imaging Sounder from Saudi Arabia. The main scientific objective of CE-4 is to provide scientific data for lunar far side research, including: 1)general spatial environmental study of lunar far side;2)general research on the surface, shallow layer and deep layer of lunar far side;3)detection of low frequency radio on lunar far side using Low Frequency Radio Detector, which would be the first time of using such frequency band in lunar exploration history .

  4. Effects of Ce on Inclusions, Microstructure, Mechanical Properties, and Corrosion Behavior of AISI 202 Stainless Steel

    Science.gov (United States)

    Cai, Guojun; Li, Changsheng

    2015-10-01

    The sizes and morphologies of nonmetallic inclusions, microhardness, tensile strength, and Charpy impact toughness in AISI 202 stainless steel with different Ce contents were synthetically analyzed by means of SEM, TEM, microhardness tester, and tensile and Charpy impact tests. Effects of Ce addition on the corrosion behavior were investigated in 5 wt.% H2SO4 solution for different periods of time through measuring AC impedance. The EIS measurements indicate that the steels with Ce addition exhibit higher R p values than those without Ce, which illustrates the relative resistance to uniform corrosion is accompanied by an increasing Ce addition. Ce addition to AISI 202 stainless steel improves its uniform corrosion resistance owing to metamorphic inclusions and the improvement of electrode potential in matrix. Upon increasing Ce addition, the indentation morphology of samples transfers from sink-in types to pile-up types, explaining good machinability of steels containing Ce. It is witnessed from the fracture mode that Ce refines the grain size of steels, significantly increasing the strength; in the meantime, its plasticity is improved, thereby solving the contradiction between the strength and the plasticity of steels. It is concluded that AISI 202 stainless steel with 0.016 wt.% Ce addition in the mass fraction has the best mechanical properties and the uniform corrosion resistance.

  5. 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.

  6. Systematic study of rotational energy formulae for superdeformed bands in La and Ce isotopes

    Science.gov (United States)

    Sharma, Honey; Mittal, H. M.

    2017-12-01

    The experimental rotational spectra of superdeformed (SD) bands of 130La, 131Ce(1,2), 132Ce(1,2,3) and 133Ce(1,2,3) in the A ∼ 130 mass region are systematically analyzed with the four parameter formula, power index formula, nuclear softness formula, and VMI model. It is observed that out of all the formulae, the four parameter formula suits best for the study of the 130La, 131Ce(1,2), 132Ce(2,3) and 133Ce(1,2,3) SD bands. The four parameter formula works efficiently in determining the band head spin of the 130La, 131Ce(1,2) 132Ce(2,3) and 133Ce(1,2,3) SD bands. Good agreement is seen between the calculated and observed transition energies whenever the accurate spin is assigned. In 132Ce(1), the power index formula is found to work better than the other three formulae. The dynamic moment of inertia is also calculated for all the formulae and its variation with the rotational frequency is investigated.

  7. Uso de práticas integrativas e complementares por doulas em maternidades de Fortaleza (CE e Campinas (SP

    Directory of Open Access Journals (Sweden)

    Raimunda Magalhães da Silva

    2016-03-01

    Full Text Available Resumo Objetivou-se analisar as Práticas Integrativas e Complementares (PICs utilizadas por doulas nos municípios de Fortaleza (CE e Campinas (SP. É um estudo de natureza qualitativa, com 15 doulas: nove de Fortaleza e seis de Campinas. Os dados foram coletados no segundo semestre de 2010, mediante a realização de entrevistas semiestruturadas, e organizados seguindo a técnica da Análise de Con teúdo na modalidade temática. A interpretação dos resultados baseou-se na noção de que a institucio nalização dos saberes se dá pela conformação de núcleos e de campos. O núcleo demarca a identidade de uma área de saber e de práticas profissionais; e o campo, um espaço de limites imprecisos entre as disciplinas, mas que pode ser submetido a conflitos. Observou-se que o suporte das doulas permeia uma variedade de práticas emolduradas na Medicina Tradicional (MT e das PICs. Essas práticas contri buíram para a diminuição do tempo de trabalho de parto, melhor controle da dor, ajuda na tomada de decisões e empoderamento da mulher. Compreende -se que o espaço de atuação da doula e o uso de PICs convergem para a singularidade, respeito e autonomia da mulher e propõem um novo modelo de saberes e práticas centrado na importância do processo natural do parto.

  8. Sonocatalytic degradation of diclofenac with FeCeOx particles in water.

    Science.gov (United States)

    Chong, Shan; Zhang, Guangming; Wei, Zhongheng; Zhang, Nan; Huang, Ting; Liu, Yucan

    2017-01-01

    This paper studies the sonocatalytic degradation of diclofenac in water using FeCeO x -catalyzed ultrasound. The effects of pre-adsorption and gas addition were investigated. Nitrogen adsorption/desorption, SEM, XRD, Raman and XPS analyses of FeCeO x before and after sonication were characterized. The proposed mechanism was based on the microstructure changes of FeCeO x and reactive-species-scavenging performances. The results show that FeCeO x has excellent performance in catalyzing an ultrasonic system in water, and 80% of diclofenac was removed in 30min ([Diclofenac]=20mg/L, FeCeO x amount=0.5g/L, pH=6, ultrasonic density=3.0W/cm 3 , ultrasonic frequency=20kHz, temperature=298K). The Fe, Ce, and O elements remained highly dispersed in the structure of FeCeO x , and the solid solution structure of FeCeO x remained stable after the reaction. Ce (III) was gradually oxidized to Ce (IV) and Fe (III) was gradually reduced to Fe (II) after the reaction, which indicates that Fe and Ce ions with different valences coexisted in dynamic equilibrium. The amount of oxygen vacancies in FeCeO x significantly decreased after the reaction, which indicates that oxygen vacancy participated in the ultrasonic process. Singlet oxygen 1 O 2 was the primary reactive species in the degradation process, and the hydroxyl radicals OH and superoxide radical anion O 2 - also participated in the reaction. FeCeO x had excellent chemical stability with negligible leaching ions in the ultrasonic process. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. 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.

  10. Highly active and durable Ca-doped Ce-SBA-15 catalyst for biodiesel production

    International Nuclear Information System (INIS)

    Thitsartarn, Warintorn; Maneerung, Thawatchai; Kawi, Sibudjing

    2015-01-01

    In this work, Ca-doped Ce-incorporated SBA-15 (Ca/CeS) catalyst was successfully synthesized by using direct synthesis of Ce-incorporated SBA-15 followed by impregnation of CaO (calcium oxide). The maximum Si/Ce molar ratio that Ce atoms can be incorporated successfully into the mesoporous framework was found to be 5 (CeS-5). After the impregnation of 30 wt. % Ca, the obtained 30Ca/CeS-5 catalysts showed the superior catalytic performance for transesterification reaction of palm oil with methanol and also the higher catalytic activity as compared to other supported catalysts, i.e. CaO/CeO 2 and CaO–CeO 2 /SBA-15. This can be attributed to the well-dispersion of CaO on the CeS-5 support surface. Furthermore, it was found that the leaching of Si, Ce and Ca from the catalyst into biodiesel produced was negligible (i.e. <1 ppm after 7 cycles), indicating the strong interaction between CaO and CeS-5 support. As a result, the 30Ca/CeS-5 catalyst can be reused at least 15 cycles with insignificant decrease in catalytic activity, offering the efficient CaO-based catalyst for biodiesel production. - Highlights: • Mesoporous Ca-based catalyst was successfully developed for biodiesel production. • Catalyst exhibited high activity towards transesterification (FAME yield > 98%). • Catalyst can be effectively re-used at least 15 cycles. • Extremely low catalyst contaminant (<1 ppm) was presented

  11. 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.

  12. Synthesis, characterization, and ecotoxicity of CeO{sub 2} nanoparticles with differing properties

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Bushra [Aero Shade Technologies Inc (United States); Philippe, Allan, E-mail: philippe@uni-landau.de; Rosenfeldt, Ricki R.; Seitz, Frank [University of Koblenz-Landau, Group of Environmental and Soil Chemistry, Institute for Environmental Sciences (Germany); Dey, Sonal [SUNY Polytechnic Institute, Colleges of Nanoscale Science and Engineering (United States); Bundschuh, Mirco; Schaumann, Gabriele E. [University of Koblenz-Landau, Group of Environmental and Soil Chemistry, Institute for Environmental Sciences (Germany); Brenner, Sara A. [SUNY Polytechnic Institute, Colleges of Nanoscale Science and Engineering (United States)

    2016-10-15

    CeO{sub 2} 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, CeO{sub 2} nanoparticle powders were prepared using three different precursors [Ce(NO{sub 3}){sub 3}, CeCl{sub 3}, and Ce(CH{sub 3}COO){sub 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 Ce{sup 3+}/Ce{sup 4+} 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 CeO{sub 2} nanoparticles underwent toxicity testing at concentrations up to 64 mg L{sup −1} using Daphnia magna. Toxic effects were observed for three particle types with EC50 values between 5 and 64 mg L{sup −1}. No clear correlation was observed between the physicochemical properties (size, shape, oxygen occupancy, Ce{sup 3+}/Ce{sup 4+} 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 CeO{sub 2} 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 CeO{sub 2} nanoparticles will cause unwanted adverse effects.

  13. Os agentes modeladores da cidade de Aracati-CE no período colonial

    Directory of Open Access Journals (Sweden)

    Maria Edivani Barbosa

    2012-01-01

    Full Text Available A cidade de Aracati (Ceará/Brasil manifesta, na morfologia urbana, vestígios do apogeu econômico, herdados do século XVIII. A arquitetura e o traçado urbano remanescentes são suportes da memória urbana e revelam singularidades locais que a distinguem de outras vilas criadas no mesmo período histórico. A organização do espaço é resultado das forças que atuaram na sua produção, como a Igreja, as irmandades religiosas, o Estado português, os agentes econômicos (fazendeiros, comerciantes e charqueadores, a Câmara municipal e demais grupos sociais. Entender a trama entre esses agentes revela momentos únicos dessa memória urbana, o que explica a produção espacial. Através da paisagem urbana, verifica-se a lógica dos elementos construídos: o traçado urbano retilíneo, com ruas largas cortadas por becos, buscava adequar-se à dinâmica econômica da época; a arquitetura residencial com fachadas iguais foram diretrizes urbanas do Governo português. Os templos religiosos refletem a influência e o poder da Igreja Católica na organização socioespacial. A construção da cidade de costas para o rio Jaguaribe se deu devido ao fato de, na época, ser considerado um local insalubre, para onde seguiam os dejetos da vila. A compreensão, no tempo e no espaço, da formação socioespacial da cidade de Aracati foi possível graças a este estudo. Résumé LES AGENTS DE MODELAGE DE LA VILLE D’ARACATI-CE DANS LA PÉRIODE COLONIALE La ville de Aracati (Ceará/Brésil, manifeste, par la morphologie urbaine, des vestiges de son apogée économique, hérités du XVIII ème siècle. L’architecture et le dessin urbain rémanents sont des supports de la mémoire e révélant des singularités locales qui la distinguent d’autres bourgs crées dans la même période historique. L’organisation de l’espace est le résultat des forces qui ont agi dans sa production, comme l’Église, les confréries religieuses, l’État portuguais

  14. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Performance evaluation of novel LaBr{sub 3}(Ce) scintillator geometries for fast-timing applications

    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, 28040 Madrid (Spain); Carmona-Gallardo, M.; Fraile, L.M. [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, 28040 Madrid (Spain); Mach, H. [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, 28040 Madrid (Spain); National Centre for Nuclear Research, Division for Nuclear Physics, BP1, Warsaw (Poland); Udías, J.M. [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, 28040 Madrid (Spain)

    2017-06-11

    We evaluate the performance of two LaBr{sub 3}(Ce) crystals that were produced with special geometries, aimed at enhancing the scintillation light collection and thus the time resolution. Their design was motivated by the construction of high-performance fast-timing arrays like the FAst TIMing array for DESPEC (FATIMA), which demands a high packing factor in addition to good time and energy resolutions. Energy resolution and efficiency were measured using standard calibration sources. Timing measurements were performed at {sup 60}Co and {sup 22}Na γ-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 constant fraction discriminator parameters. Monte Carlo simulations using the Geant4 toolkit were performed in order to achieve a better understanding of how the new geometries affect the light transport and thus the performance of the crystals. It is found that the conical-shaped LaBr{sub 3}(Ce) crystals are optimal for fast-timing applications and for the construction of arrays such as FATIMA.

  16. Synthesis of cerium oxide (CeO2) with high surface area through microwave assisted hydrothermal method

    International Nuclear Information System (INIS)

    Oliveira, M.J.C. de; Neiva, L.S.; Gama, L.; Oliveira, J.B.

    2011-01-01

    The objective of this research is synthesize nanoparticles with high surface area of Ceria (CeO 2 ) catalyst by a microwave hydrothermal method. For that it was used a 5% concentration in weight of [Ce(NO 3 ) 3. 6H 2 O] and 10 mL of [NaOH (5M)] under processing conditions in the equipment: maximum temperature of 150 deg C for 60 min with heating rate of 15 C /min. The resulting sample was characterized by XRD, SEM and BET method. It was observed that the Ceria particles are presented spatially in cubic structure, with crystallite size of 10 nm and surface area of 112 m²/g. Through the pore size distribution it was possible to observe that these were in mesoporous size, ranging from 3 to 30 nm. The possibility of obtaining catalysts with nanometer scale and high surface area by beans of microwave hydrothermal method, which involves low energy (low temperatures) and short synthesis time, makes this method very interesting and promising. (author)

  17. 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

  18. Ground tests with prototype of CeBr{sub 3} active gamma ray spectrometer proposed for future venus surface missions

    Energy Technology Data Exchange (ETDEWEB)

    Litvak, M.L., E-mail: litvak@mx.iki.rssi.ru [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Sanin, A.B.; Golovin, D.V. [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Jun, I. [Jet Propulsion Laboratory, Pasadena, CA (United States); Mitrofanov, I.G. [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Shvetsov, V.N.; Timoshenko, G.N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Vostrukhin, A.A. [Space Research Institute, RAS, Moscow 117997 (Russian Federation)

    2017-03-11

    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 (CeBr{sub 3}) 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.

  19. Experimental study on polishing performance of CeO2 and nano-SiO2 mixed abrasive

    Science.gov (United States)

    He, Qiang

    2018-02-01

    In this paper, superfine SiO2 nanoparticles are utilized as composite abrasive additive to improve the polishing property of CeO2, which is prepared through chemical precipitation method by rare-earth chloride as raw materials, silicofluoric acid as fluoride, Na2CO3 as modifier, and NH4HCO3 as precipitator. XRD, SEM, particle size analyzer, and atomic force microscopy are applied to characterize the physical structure, morphology, and size distribution. Furthermore, the as-prepared composite abrasive is used to perform chemical mechanical polishing (CMP) experiment on K9 glass to identify the impact of different mass fraction of SiO2 on the CMP property of work materials. The results show that the composite abrasive contained 0.5% SiO2 has the best polishing property, the surface roughness, and material removal rate of glass after polishing can reach at 1.3157 nm and 22.6 nm/min, respectively.

  20. 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.

  1. 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.

  2. 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

    resistance of the buffer-filled capillary. The temperature-correlated mobility calculation eliminates the peak shifts due to the viscosity changes, improves the precision of peak identification using the observed temperature-correlated mobilities and allows a direct comparison of signals from different......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...

  3. Structural aspects of the new quasi-2-D heavy fermion materials CeIrIns and CeRhIns

    International Nuclear Information System (INIS)

    Moshopoulou, E.G.; Moshopoulou, E.G.; Fisk, Z.; Sarrao, J.L.; Thompson, J.D.; Fisk, Z.

    2002-01-01

    The title compounds are new heavy fermion materials. They adopt a quasi two-dimensional crystal structure and exhibit unusual (for a heavy fermion system) low temperature properties. Although the study of their physical and structural behaviour at low temperatures and/or high pressures is still in progress, we present here some results concerning their average crystal structure, and we discuss very briefly their similarities and differences with the compounds CeIn3 and UTGa 5 (T: Co, Ni, Ir, Pd, Cu, Ru). (authors)

  4. 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 ...

  5. 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.

  6. Gapless Fermi surfaces in superconducting CeCoIn5

    Science.gov (United States)

    Barzykin, Victor; Gor'Kov, L. P.

    2007-07-01

    According to Tanatar [Phys. Rev. Lett. 95, 067002 (2005)], the low-temperature thermal conductivity in Ce1-xLaxCoIn5 , a multiband d -wave superconductor, reveals unexpected dependence on the concentration of defects as if one or more Fermi surface sheets remained ungapped below superconducting transition. The interior gap superfluidity mechanism, or unbalanced pairing, recently proposed by Liu and Wilczek [Phys. Rev. Lett. 90, 047002 (2003)] has been invoked as a possible origin of gaplessness. We indicate that the Fermi surface anisotropy in the real CeCoIn5 makes this explanation highly implausible. We emphasize the fundamental difference between unbalanced pairing of different Fermi entities and the formation of superconducting gaps on Fermi surfaces belonging to different bands. We also argue that interband interactions between electrons always induce a finite order parameter on all Fermi surfaces below the temperature of a superconducting transition. We calculate specific heat and thermal conductivity in a two-band model for a d -wave superconductor in the presence of defects. In our simple model, superconductivity originates on one Fermi surface, inducing a smaller gap on the other one. Impurities diminish the induced gap and increase the density of states, restoring rapidly the Wiedemann-Franz law for this Fermi surface. Our calculations are in agreement with experiment.

  7. The Asia-RiCE activity with data cube

    Science.gov (United States)

    Oyoshi, K.; Sobue, S.; LE Toan, T.; Lam, N. D.

    2017-12-01

    The Asia-RiCE initiative (http://www.asia-rice.org) has been organized to enhance rice production estimates through the use of Earth observation satellites data, and seeks to ensure that Asian rice crops are appropriately represented within GEO Global Agriculture Monitoring (GEO-GLAM) to support FAO Agriculture Market Information System (FAO-AMIS). Asia-RiCE is composed of national teams that are actively contributing to the Crop Monitor for AMIS and developing technical demonstrations of rice crop monitoring activities using both Synthetic Aperture Radar (SAR) data (Radarsat-2 from 2013; Sentinel-1 and ALOS-2 from 2015.From 2016 after the successful rice crop area and growing estimation using SAR in a technical demonstration site (provincial level), wall-to-wall (national scale) excurse as phase 2 has been implemented in Vietnam and Indonesia in cooperation with ministry of agriculture and space agencies. This paper reports this year activity of 2017 accomplishment and way forward, especially for analysis ready data (ARD) definition of SAR to ingest to CEOS data cube to provide national scale service in Vietnam and Indonesia.

  8. Magnetoresistance and magnetization anomalies in CeB6

    International Nuclear Information System (INIS)

    Bogach, A.V.; Glushkov, V.V.; Demishev, S.V.; Samarin, N.A.; Paderno, Yu.B.; Dukhnenko, A.V.; Shitsevalova, N.Yu.; Sluchanko, N.E.

    2006-01-01

    High precision magnetoresistance (MR) Δρ/ρ(H,T) and magnetization M(H,T) measurements have been carried out for well known and typical strongly correlated electron system-cerium hexaboride. The detailed measurements have been fulfilled on single crystalline samples of CeB 6 over a wide temperature range T>=1.8K in magnetic fields up to 70kOe. It was shown that the MR anomalies in the magnetic heavy fermion compound under investigation can be consistently interpreted in the frameworks of a simple relation between resistivity and magnetization-Δρ/ρ∼M 2 obtained by Yosida [Phys. Rev. 107(1957)396]. A local magnetic susceptibility χ loc (T,H)=(1/H*(d(Δρ/ρ)/dH)) 1/2 was deduced directly from the MR Δρ(H,T) measurements and compared with the experimental data of magnetization M(H,T). The magnetic susceptibility dependences χ loc (T,H) and χ(T,H) obtained in this study for CeB 6 allow us to analyze the complicated H-T magnetic phase diagram of this so-called dense Kondo-system

  9. Ceļa servitūts

    OpenAIRE

    Livdāns, Dāvis

    2016-01-01

    Bakalaura darba tēma ir “Ceļa servitūts.” Bakalaura darba mērķis ir izpētīt ceļa servitūta nodibināšanas kārtību, iespējamās kļūdas, praksē nodibināto servitūtu problēmjautājumus un to risinājumus. Bakalaura darba tapšanas stadijā autors izmantoja zinātnisko literatūru, normatīvos aktus, kā arīi ar to tapšanu saistītos dokumentus un juridiskās prakses materiālus. Darbā ir apskatīti gan Civillikumā noteiktie servitūtu nodibināšanas pamati, gan citi iespējamie nodibināšanas pamati, pēc kā ir an...

  10. Otology at the Academy of Gondishapur 200-600 CE.

    Science.gov (United States)

    Ruben, Robert J

    2017-12-01

    To investigate the way in which otology was practiced at the Academy of Gondishapur in ancient Persia from 200 to 600 CE. The pertinent literature, using German and English translations of Latin, Greek, Arabic, and Sanskrit documents, was identified and reviewed through the indices of available books and through a PDF search for the following topics: auricle, deaf, deafness, dizziness, ear, hearing, medicine, otitis, pinna, punishment-ear, speech, surgery, vertigo, and voice. The medical school at the Academy of Gondishapur followed the medical and surgical practices of Greece and Rome and, in the 6th century, incorporated those from India as detailed in the Shutra Samhita. This shutra, which originated during the first millennium BCE, detailed many interventions, among which one of the most unusual was the use of a pedicle cheek flap to restore the pinnae. The use of the pedicle flap for pinna restoration appears not have been reported in literature again until 1931, by Jacque Joseph. During the period of late antiquity, medical knowledge of both the east and west was preserved and taught in Persia. Among surgical interventions used during the first millennium BCE in India, knowledge of which passed, through the shutra, to the Sasanian Empire in the 6th century CE, was use of the pedicle cheek flap for pinna reconstruction. Even as late as the Renaissance, the pedicle flap was not known to surgeons in the West, and a pedicle flap, though not a cheek flap, was first incorporated into Western medical practice during the 1930s.

  11. 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...

  12. Irradiation effects in UO2 and CeO2

    International Nuclear Information System (INIS)

    Ye, Bei; Oaks, Aaron; Kirk, Mark; Yun, Di; Chen, Wei-Ying; Holtzman, Benjamin; Stubbins, James F.

    2013-01-01

    Single crystal CeO 2 , as a surrogate material to UO 2 , was irradiated with 500 keV xenon ions at 800 °C while being observed using in situ transmission electron microscopy (TEM). Experimental results show the formation and growth of defect clusters including dislocation loops and cavities as a function of increasing atomic displacement dose. At high dose, the dislocation loop structure evolves into an extended dislocation line structure, which appears to remain stable to the high dose levels examined in this study. A high concentration of cavities was also present in the microstructure. Despite high atomic displacement doses, the specimen remained crystalline to a cumulated dose of 5 × 10 15 ions/cm 2 , which is consistent with the known stability of the fluorite structure under high dose irradiation. Kinetic Monte Carlo calculations show that oxygen mobility is substantially higher in hypo-stoichiometric UO 2 /CeO 2 than hyper-stoichiometric systems. This result is consistent with the ability of irradiation damage to recover even at intermediate irradiation temperatures

  13. Genome Mining in Sorangium cellulosum So ce56

    Science.gov (United States)

    Ewen, Kerstin Maria; Hannemann, Frank; Khatri, Yogan; Perlova, Olena; Kappl, Reinhard; Krug, Daniel; Hüttermann, Jürgen; Müller, Rolf; Bernhardt, Rita

    2009-01-01

    Myxobacteria, especially members of the genus Sorangium, are known for their biotechnological potential as producers of pharmaceutically valuable secondary metabolites. The biosynthesis of several of those myxobacterial compounds includes cytochrome P450 activity. Although class I cytochrome P450 enzymes occur wide-spread in bacteria and rely on ferredoxins and ferredoxin reductases as essential electron mediators, the study of these proteins is often neglected. Therefore, we decided to search in the Sorangium cellulosum So ce56 genome for putative interaction partners of cytochromes P450. In this work we report the investigation of eight myxobacterial ferredoxins and two ferredoxin reductases with respect to their activity in cytochrome P450 systems. Intriguingly, we found not only one, but two ferredoxins whose ability to sustain an endogenous So ce56 cytochrome P450 was demonstrated by CYP260A1-dependent conversion of nootkatone. Moreover, we could demonstrate that the two ferredoxins were able to receive electrons from both ferredoxin reductases. These findings indicate that S. cellulosum can alternate between different electron transport pathways to sustain cytochrome P450 activity. PMID:19696019

  14. Effect of nano-CeO2 on microstructure properties of TiC/TiN+TiCN ...

    Indian Academy of Sciences (India)

    TiC/TiN+TiCN-reinforced composite coatings were fabricated on Ti–6Al–4V alloy by laser cladding, ... Ce was able to refine the microstructure of laser-cladded .... According to the report by Tian et al. (2006), during the cladding process, a portion of CeO2 was decomposed as follows: CeO2 →Ce + O2 ↑. (2). Then, Ce was ...

  15. Particle-specific toxicity and bioavailability of cerium oxide (CeO{sub 2}) nanoparticles to Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xinping; Pan, Haopeng [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Wang, Peng, E-mail: p.wang3@uq.edu.au [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); The University of Queensland, School of Agriculture and Food Sciences, St. Lucia, Queensland 4072 (Australia); Zhao, Fang-Jie [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom)

    2017-01-15

    Highlights: • The phytotoxicity and uptake of CeO{sub 2} NPs were examined in Arabidopsis. • CeO{sub 2} NPs stimulated plant growth at low doses but were toxic at high doses. • The toxicity was due to the NPs per se, rather than from the dissolved Ce ions. • A similar up-translocation factor was found for CeO{sub 2} NPs, bulk CeO{sub 2} and Ce ions. - Abstract: The use of manufactured cerium oxide nanoparticles (CeO{sub 2}-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 CeO{sub 2}-NPs in Arabidopsis thaliana grown in an agar medium. Although low concentrations of CeO{sub 2}-NPs had stimulatory effects on plant growth, at higher concentrations, CeO{sub 2}-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. CeO{sub 2}-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. CeO{sub 2}-NPs, CeO{sub 2}-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 CeO{sub 2}-NPs in plants, which needs to be considered in environmental risk assessment for the safe use and disposal of CeO{sub 2}-NPs.

  16. Excitation light source dependence of emission in Sn2+-Ce3+ codoped ZnO-P2O5 glasses

    OpenAIRE

    Masai, Hirokazu; Hino, Yusuke; Yanagida, Takayuki; Fujimoto, Yutaka; Fukuda, Kentaro; Yoko, Toshinobu

    2013-01-01

    Correlation between excitation light source and the emission property of Sn^{2+}-Ce^{3+} co-doped zinc phosphate glasses is examined. Although photoluminescence (PL) peaks of both Sn^{2+}and Ce^{3+} shifted with increasing amount of Ce^{3+}, there was little energy resonance between Sn^{2+} and Ce^{3+} emission centers. On the other hand, radioluminescence (RL) spectra excited by X-ray was independent of the Ce concentration, indicating that emission was mainly observed from Sn^{2+} emission ...

  17. Anisotropy of the Kondo insulator CeRu4Sn6

    International Nuclear Information System (INIS)

    Paschen, S; Winkler, H; Nezu, T; Kriegisch, M; Hilscher, G; Custers, J; Prokofiev, A; Strydom, A

    2010-01-01

    The intermetallic compound CeRu 4 Sn 6 has tentatively been classified as Kondo insulator. Its tetragonal crystal structure places it inbetween the archetypal Kondo insulators like YbB 12 or Ce 3 Bi 4 Pt 3 , which are cubic, and the orthorhombic 'Kondo semimetals' CeNiSn and CeRhSb. It is of great interest to investigate possible anisotropies - or even nodes - of the Kondo insulating gap in CeRu 4 Sn 6 . We have succeeded, for the first time, to grow single crystals of this compound. Interestingly, we could not only reveal anisotropy between the tetragonal c direction and the tetragonal a-a plane but even within a quasi-cubic cell which happens to be formed in CeRu 4 Sn 6 because the length of the diagonal of the tetragonal plane c' = √2a differs from c by only 0.2%.

  18. Adsorption process of fluoride from drinking water with magnetic core-shell Ce-Ti@Fe3O4 and Ce-Ti oxide nanoparticles.

    Science.gov (United States)

    Abo Markeb, Ahmad; Alonso, Amanda; Sánchez, Antoni; Font, Xavier

    2017-11-15

    Synthesized magnetic core-shell Ce-Ti@Fe 3 O 4 nanoparticles were tested, as an adsorbent, for fluoride removal and the adsorption studies were optimized. Adsorption capacity was compared with the synthesized Ce-Ti oxide nanoparticles. The adsorption equilibrium for the Ce-Ti@Fe 3 O 4 adsorbent was found to occur in Ti oxides and Ce-Ti@Fe 3 O 4 nanoparticles, respectively. The physical sorption mechanism was estimated using the Dubinin-Radushkevich model. An anionic exchange process between the OH - group on the surface of the Ce-Ti@Fe 3 O 4 nanomaterial and the F - was involved in the adsorption. Moreover, thermodynamic parameters proved the spontaneous process for the adsorption of fluoride on Ce-Ti@Fe 3 O 4 nanoparticles. The reusability of the material through magnetic recovery was demonstrated for five cycles of adsorption-desorption. Although the nanoparticles suffer slight structure modifications after their reusability, they keep their adsorption capacity. Likewise, the efficiency of the Ce-Ti@Fe 3 O 4 was demonstrated when applied to real water to obtain a residual concentration of F - below the maximum contaminated level, 1.5mg/L (WHO, 2006). Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Influence of synthesis conditions on the crystal structure of the powder formed in the ZrO2 - Ce2O3/CeO2 system

    International Nuclear Information System (INIS)

    Popov, V V; Menushenkov, A P; Khubbutdinov, R M; Sharapov, A S; Svetogorov, R D; Zubavichus, Ya V; Kurilkin, V V

    2016-01-01

    Influence of synthesis conditions (type of atmosphere, reduction and oxidation, annealing temperature) on the chemical composition and structure of the compounds formed in the “ZrO 2 - Ce 2 O 3 / CeO 2 ” 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 Ce 0.5 Zr 0.5 O 2 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 Ce 4 + 2xCe 3 + 2-2xZr 2 O 7 + 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 Ce 4 + in a powder samples and leads to formation of pyrochlore structure (space group Fd-3 m ) with practically Ce 3+ valence state. (paper)

  20. 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.

  1. Assessment of social security policy on access perspective of rural workers : Community Case Study Bom Jesus , Fixing Maceià - Itapipoca -Ce

    OpenAIRE

    KÃlia da Silva Aires

    2013-01-01

    A proposta desenvolvida neste trabalho à avaliar a polÃtica de PrevidÃncia Social na perspectiva do acesso das trabalhadoras rurais da comunidade Bom Jesus, Assentamento Maceià â Itapipoca- CE. A pesquisa tem enfoque qualitativo e a investigaÃÃo se procedeu por meio de um estudo de caso que investigou os fatores limitantes desse acesso. Para tanto foi realizada uma avaliaÃÃo de processo e resultados inspirada nos preceitos da avaliaÃÃo em profundidade. SÃo sujeitos da pesquisa avaliativa os t...

  2. Les Nigérianes améliorent leur sort grâce aux légumes indigènes

    International Development Research Centre (IDRC) Digital Library (Canada)

    à rester en santé. Malgré ce potentiel, la recherche n'a pas accordé la priorité aux espèces de légumes indigènes pour améliorer la sécurité alimentaire, la nutrition et les ... vue d'améliorer la sécurité alimentaire en milieu rural a porté sur la mise au .... germination, la lutte biologique contre les ravageurs et le tuteurage de ...

  3. “Trabalhadas no feminino”: um estudo sobre corpo, desejo e prostituição travesti em Fortaleza-CE

    OpenAIRE

    Francisco Jander De Sousa Nogueira; Adriano Gomes de León

    2012-01-01

    Este trabalho toma como foco de análise travestis que se prostituem na cidade de Fortaleza‐Ce. São apresentadas narrativas sobre suas transformações corporais, experiência que engloba um conjunto de processos e vivências. Contrastando com concepções de identidades que privilegiam a coerência e a linearidade, apresento trajetórias e relatos autobiográficos contextualizados por descontinuidades. Travestis efetuam transformações em suas formas físicas, seja com o aval da medicina ...

  4. Equilibrium studies on some binary complexes of La(III), Ce(III), Pr(III) and Nd(III) with ligands containing N-N donor atoms

    International Nuclear Information System (INIS)

    Pabreja, D.S.; Patel, Rashmikant A.; Sharma, Sangita; Vora, Jabali; Joshi, J.D.

    2001-01-01

    The present paper describes a potentiometric study on formation constants of binary complexes of inner transition 4f metal ions La(III), Ce(III), Pr(III) and Nd(III) with amines such as ethylenediamine, N-N-dimethyl ethylenediamine, N-N-diethyl ethylenediamine, 1,2-diaminopropane and 1,3-diaminopropane carried out at constant temperature 30± 0.1deg C and ionic strength μ 0.2 M dm -3 (NaClO 4 ). Various factors influencing the formation and stabilities of binary complexes have been discussed. (author)

  5. Laser clad Ni-base alloy added nano- and micron-size CeO 2 composites

    Science.gov (United States)

    Zhang, Shi Hong; Li, Ming Xi; Cho, Tong Yul; Yoon, Jae Hong; Lee, Chan Gyu; He, Yi Zhu

    2008-07-01

    Micron-size Ni-base alloy (NBA) powders are mixed with both 1.5 wt% (%) micron-CeO 2 (m-CeO 2) and also 1.0-3.0% nano-CeO 2 (n-CeO 2) powders. These mixtures are coated on low carbon steel (Q235) by 2.0 kW CO 2 laser cladding. The effects on microstructures, microhardness and wear resistance of the coating by the addition of m- and n-CeO 2 powders to NBA (m- and n-CeO 2/NBA) have been investigated. Addition to the primary phases of γ-Ni, Cr 23C 6 and Ni 3B of NBA coating, CeNi 3 shows up both in m- and n-CeO 2/NBA coatings and CeNi 5 appears only in n-CeO 2/NBA coating. Directional dendrite and coarse equiaxed dendrite are grown in m-CeO 2/NBA coating from interface to central zone, whereas multi-oriented dendrite and fine equiaxed dendrite growth by addition of n-CeO 2. The microhardness and wear resistance of coatings are greatly improved by CeO 2 powder addition, and compared to the addition of 1.0% and 3.0%, 1.5% n-CeO 2/NBA is the best. Hardness and wear resistance of the coating improves with decreasing CeO 2 size from micron to nano.

  6. Paramagnetic Ce3 + optical emitters in garnets: Optically detected magnetic resonance study and evidence of Gd-Ce cross-relaxation effects

    Science.gov (United States)

    Tolmachev, D. O.; Gurin, A. S.; Uspenskaya, Yu. A.; Asatryan, G. R.; Badalyan, A. G.; Romanov, N. G.; Petrosyan, A. G.; Baranov, P. G.; Wieczorek, H.; Ronda, C.

    2017-06-01

    Paramagnetic Ce3 +optical emitters have been studied by means of optically detected magnetic resonance (ODMR) via Ce3 + spin-dependent emission in cerium-doped garnet crystals which were both gadolinium free and contain gadolinium in a concentration from the lowest (0.1%) to 100%, i.e., to the superparamagnetic state. It has been shown that the intensity of photoluminescence excited by circularly polarized light into Ce3 + absorption bands can be used for selective monitoring the population of the Ce3 + ground-state spin sublevels. Direct evidence of the cross-relaxation effects in garnet crystals containing two electron spin systems, i.e., the simplest one of Ce3 + ions with the effective spin S =1/2 and the system of Gd3 + ions with the maximum spin S =7/2 , has been demonstrated. Magnetic resonance of Gd3 + has been found by monitoring Ce3 + emission in cerium-doped garnet crystals with gadolinium concentrations of 0.1 at. %, 4%-8%, and 100%, which implies the impact of the Gd3 + spin polarization on the optical properties of Ce3 +. Strong internal magnetic fields in superparamagnetic crystals were shown to modify the processes of recombination between UV-radiation-induced electron and hole centers that lead to the recombination-induced Ce3 + emission. Observation of spikes and subsequent decay in the cross-relaxation-induced ODMR signals under pulsed microwave excitation is suggested to be an informative method to investigate transient processes in the many-spin system of Ce3 +, Gd3 +, and electron and hole radiation-induced centers.

  7. Eu and Sr2CeO4 : Eu phosphors suitable for near ultraviolet excitation

    Indian Academy of Sciences (India)

    Administrator

    et al 2009). It absorbs ultraviolet radiation and emits white light, when activated by Eu2+ ions. It is anticipated that the dual behaviour of Sr2CeO4 : Eu3+ and Sr2CeO4 : Eu2+ phosphors ... in stoichiometric proportions (Sr : Ce is 2 : 1) and Eu2O3. (National ..... Zhang C X, Jiang W J and Yang X J 2009 J. Alloys Compd. 474.

  8. Electrical resistivity of CeTIn{sub 5} (T=Rh, Ir) under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Muramatsu, Takaki; Kobayashi, Tatsuo C.; Shimizu, Katsuya; Amaya, Kiichi; Aoki, Dai; Haga, Yoshinori; Onuki, Yoshichika

    2003-05-15

    We have studied the superconducting properties of CeTIn{sub 5} (T=Rh, Ir) under high pressures by means of electrical resistivity measurements and determined the pressure-temperature phase diagrams for the superconducting transition. For both systems, the superconductivity exists in a wide pressure range, 1.5{<=}P{<=}6.5 GPa for CeRhIn{sub 5} and 0{<=}P{<=}5.2 GPa for CeIrIn{sub 5}.

  9. Scintillation response comparison among Ce-doped aluminum gartnes, perovskites and orthosilicates

    Czech Academy of Sciences Publication Activity Database

    Mareš, Jiří A.; Nikl, Martin; Mihóková, Eva; Vedda, A.; D´Ambrosio, C.

    2008-01-01

    Roč. 55, č. 3 (2008), s. 1142-1147 ISSN 0018-9499 R&D Projects: GA AV ČR 1QS100100506 Institutional research plan: CEZ:AV0Z10100521 Keywords : scintillation response * Ce 3+ -doped aluminum perovskites * Ce 3+ -doped garnets, * Ce 3+ -doped orthosilicates Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.518, year: 2008

  10. Spray deposited CeO2–TiO2 counter electrode for electrochromic ...

    Indian Academy of Sciences (India)

    Abstract. Optically passive thin films of CeO2–TiO2 mixed oxides with molar ratio of Ce/Ti of 0.05 were deposited by the spray pyrolysis technique (SPT) on a glass and fluorine-doped tin oxide (FTO)-coated glass substrates. Precur- sor solution containing cerium nitrate hexahydrate (Ce(NO3)2·6H2O) and titanium ...

  11. Incommensurate antiferromagnetism and magnetic correlations in CeCu6-xAux

    DEFF Research Database (Denmark)

    Stockert, O.; Lohneysen, H. von; Schröder, A.

    1997-01-01

    Magnetic ordering and correlations in single crystals of the heavy-fermion alloys CeCu5.8Au0.2 and CeCu5.9Au0.1 were investigated by elastic and inelastic neutron scattering. CeCu5.8Au0.2 orders with an incommensurate magnetic structure and a wave vector q = (+/- 0.79 0 0). Only dynamic...

  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. 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)

  14. Thermal Variance Investigation and Scintillation Mechanisms of Cs2LiLaBr6-xClx:Ce (CLLBC) and Cs2LiYBr6:Ce (CLYB)

    International Nuclear Information System (INIS)

    Coupland, Daniel David Schechtman; Budden, Brent Scott; Stonehill, Laura Catherine

    2015-01-01

    We perform an investigation into the scintillation processes and performance of elpasolites Cs 2 LiLaBr 6-x Cl x :Ce (CLLBC) and Cs 2 LiYBr 6 :Ce (CLYB) using a thermal cycle over a range of -20 to +50°C. At 10° increments, we acquire data with both a waveform digitizer and charge-integrating electronics. We identify decay components and evaluate decay times, thermal neutron gamma-equivalent energy (GEE), and pulse shape discrimination (PSD) performance. Results are compared to common Cs 2 LiYCl 6 :Ce (CLYC).

  15. 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)

  16. Untangling the cerium and iron contributions to the magnetism of Ce-doped yttrium iron garnet

    Science.gov (United States)

    Herranz, G.; Casals, B.; Cichelero, R.; Fontcuberta, J.; Vasili, H. B.; Gargiani, P.; Valvidares, M.; Herrero-Martin, J.; Pellegrin, E.; Geshev, J.

    Due to their large magneto-optic responses, rare-earth-doped yttrium iron garnets, Y3Fe5O12 (YIG), are highly regarded for their potential in photonics and magnonics. Here we consider the case of Ce-doped YIG (Ce-YIG), in which substitutional Ce3+ ions are magnetic because of their 4f1 ground state. Hence, it is expected that Ce substitution can remarkably impact on the magnetization of YIG. However, it is not completely understood how exactly the Ce ions contribute to the macroscopic magnetic properties. Having this in mind, we have carried out magneto-optical and soft x-ray spectroscopy measurements on Ce-YIG thin films. In particular, we have used the element-specificity of XMCD to extract the individual magnetic hysteresis loops linked to Ce3+ and Fe3+ ions, respectively. Our results show that the doping of YIG with Ce causes a disruption of the electronic and magnetic properties of the parent compound, which results into a reduction of the magnetic coupling between the Ce and Fe magnetic moments, especially at low magnetic fields. Our results are relevant for the understanding of magnetism in rare-earth doped YIG and, eventually, may enable a quantitative evaluation of the magneto-optic properties of rare earth incorporation into YIG.

  17. Ce doped NiO nanoparticles as selective NO2 gas sensor

    Science.gov (United States)

    Gawali, Swati R.; Patil, Vithoba L.; Deonikar, Virendrakumar G.; Patil, Santosh S.; Patil, Deepak R.; Patil, Pramod S.; Pant, Jayashree

    2018-03-01

    Metal oxide gas sensors are promising portable gas detection devices because of their advantages such as low cost, easy production and compact size. The performance of such sensors is strongly dependent on material properties such as morphology, structure and doping. In the present study, we report the effect of cerium (Ce) doping on nickel oxide (NiO) nano-structured thin film sensors towards various gases. Bare NiO and Ce doped NiO nanoparticles (Ce:NiO) were synthesized by sol-gel method. To understand the effect of Ce doping in nickel oxide, various molar percentages of Ce with respect to nickel were incorporated. The structure, phase, morphology and band-gap energy of as-synthesized nanoparticles were studied by XRD, SEM, EDAX and UV-vis spectroscopy. Thin film gas sensors of all the samples were prepared and subjected to various gases such as LPG, NH3, CH3COCH3 and NO2. A systematic and comparative study reveals an enhanced gas sensing performance of Ce:NiO sensors towards NO2 gas. The maximum sensitivity for NO2 gas is around 0.719% per ppm at moderate operating temperature of 150 °C for 0.5% Ce:NiO thin film gas sensor. The enhanced gas sensing performance for Ce:NiO is attributed to the distortion of crystal lattice caused by doping of Ce into NiO.

  18. Fabrication, optical and scintillation properties of transparent YAG:Ce ceramics

    Science.gov (United States)

    Osipov, V. V.; Ishchenko, A. V.; Shitov, V. A.; Maksimov, R. N.; Lukyashin, K. E.; Platonov, V. V.; Orlov, A. N.; Osipov, S. N.; Yagodin, V. V.; Viktorov, L. V.; Shulgin, B. V.

    2017-09-01

    Highly transparent YAG:Ce ceramics (transmission of 72-82% for 2-mm-thick samples in 550-900 nm wavelength range) were fabricated by solid-state reactive sintering using a mixture of Ce2xY2-2xO3 (x = 0.001, 0.01, 0.03, and 0.05) and Al2O3 nanopowders synthesized by laser ablation with an additional round of pre-calcining before compaction. The synthesized YAG:Ce ceramic materials showed intense luminescence with a maximum at 525-545 nm. The measured absolute light yields of the synthesized YAG:Ce ceramics were 18-21 photon/MeV for 1-5 at.% Ce and 5 photon/MeV for 0.1 at.% Ce. The energy resolutions of the fabricated thin ceramic samples (2 mm) under 662 keV gamma ray were measured to be 10-15%. The decay curves of scintillations consisted of two components with the decay times depending on the Ce3+ concentration. The sample doped with 5 at.% of Ce exhibited the main fast component with 26 ns decay time. The measured data was compared to that of YAG:Ce and well-known CsI:Tl single crystal scintillators. The influence of dopant concentration on the optical, luminescence and scintillation properties was discussed.

  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. Effects of Ce, La and Ba addition on the electrochemical behavior of super duplex stainless steels

    International Nuclear Information System (INIS)

    Yoo, Yun-Ha; Choi, Yoon-Seok; Kim, Jung-Gu; Park, Yong-Soo

    2010-01-01

    The effects of rare earth metal (REM: Ce, La) and Ba addition on aqueous corrosion properties of super duplex stainless steels (SDSS) were investigated by electrochemical tests and surface analyses. The results of potentiodynamic test indicated that the passive range increased by the addition of Ce, La, and Ba, indicating increased relative resistance to localized corrosion. The EIS measurements showed that the Ce-La-Ba-bearing alloys exhibited higher R ct and R p values than the Ce-La-Ba-free alloy at the passive and breakdown states. Furthermore, the additions of REMs and Ba together promoted the formation of dense chromium-enriched passive film.

  1. Complex impedance study on nano-CeO2 coating TiO2

    International Nuclear Information System (INIS)

    Zhang Mei; Wang Honglian; Wang Xidong; Li Wenchao

    2006-01-01

    Titanium dioxide (TiO 2 ) nanoparticles and cerium dioxide (CeO 2 ) nanoparticles coated titanium dioxide (TiO 2 ) nanoparticles (CeO 2 -TiO 2 nanoparticles) have been successfully synthesized by sol-gel method. The complex impedance of the materials was investigated. The grain resistance, boundary resistance and activation energy of the nanoparticles were calculated according to Arrhenius equation. According to calculating results, the active capacity of pure TiO 2 nanoparticles has been improved because of nano-CeO 2 coating. An optimal CeO 2 content of 4.9 mol% was achieved. The high resolution electron microscopy images of CeO 2 -TiO 2 nanoparticles showed that TiO 2 nanoparticles, as a core, were covered by CeO 2 nanoparticles. The average size of CeO 2 coating TiO 2 nanoparticles was about 70 nm. Scanning electron microscopy observation indicted that CeO 2 nanoparticle coating improved the separation, insulation, and stability the CeO 2 -TiO 2 nanoparticles, which was benefit to the activity of materials

  2. Thermopower studies of doped CeAl sub 2 and UAl sub 2

    CERN Document Server

    Park, J G

    1997-01-01

    We have studied the thermopower of U doped CeAl sub 2 and Ce and La doped UAl sub 2. Despite different ground state properties of CeAl sub 2 and UAl sub 2 , the former being an antiferromagnetic heavy-fermion compound and the latter non-magnetic, we have found that not only thermopower data for pure CeAl sub 2 and UAl sub 2 are similar but also the thermopower results of doped samples behave similarly. Although the similarity seen in pure systems is yet to be understood, we interpret the doping effects as the results of changes in energy dependent relaxation time with doping. (author)

  3. Spectrometric performances of high quantum efficiency multi and single anode PMTs coupled to LaBr3(Ce) crystal

    Energy Technology Data Exchange (ETDEWEB)

    Cinti, Maria Nerina, E-mail: marianerina.cinti@uniroma1.it [Department of Molecular Medicine, Sapienza University of Rome, Rome 00161 (Italy); INFN Rome 1 Section, Rome (Italy); Pani, Roberto; Pellegrini, Rosanna [Department of Molecular Medicine, Sapienza University of Rome, Rome 00161 (Italy); INFN Rome 1 Section, Rome (Italy); Bennati, Paolo [Department of Molecular Medicine, Sapienza University of Rome, Rome 00161 (Italy); Orlandi, Chiara [Medical Physics Post Graduate School, Sapienza University of Rome, Rome 00161 (Italy); Fabbri, Andrea [Department of Physics, Roma Tre University, Rome (Italy); INFN Rome 3 Section, Rome (Italy); Ridolfi, Stefano; Scafè, Raffaele [Department of Molecular Medicine, Sapienza University of Rome, Rome 00161 (Italy)

    2013-10-01

    High quantum efficiency semiconductor photodetectors have recently drawn the attention of the scientific community for their potential in the realization of a new class of scintillation imagers with very high energy and spatial resolution performance. However, this goal does not seem within easy reach, due to various technological issues such as, for example, the difficulty to scale the characteristics of a single detector to an imager with suitable dimensions. Lately a definite technical improvement in increasing quantum efficiency up to 42% for position sensitive photomultipliers was achieved. The aim of this work is thus to test this new technological progress and to study the possible implications in imaging applications. Four Hamamatsu PMTs were tested: two multi anode photomultipliers, one with a bialkali (27% quantum efficiency) and the other one with a super-bialkali photocathode (38% quantum efficiency), and two 1×1 in. PMTs, both equipped with an ultra bialkali photocathode (42% quantum efficiency). In particular one of the ultra bialkali PMT has also an increased efficiency of first dynode charge collection. The results were compared with the ones obtained with a reference PMT (Hamamatsu R6231), mainly used in spectroscopy. The PMTs were coupled to LaBr3(Ce), NaI(Tl) and LSO(Ce) continuous scintillation crystals. The tests were done using two independent electronic chains: one dedicated for spectroscopic application and a second one, using a multi wire 64 channel readout, for imaging applications. The super-bialkali MA-PMTs have shown high energy resolution, both with spectroscopic and imaging setup, highlighting the appropriateness of these devices for the development of imaging devices with high spectroscopic performance. -- Highlights: • A study of energy resolution results coming from position sensitive photomultipliers are proposed. • The study is also extended on mono- anode photomultiplier. • The selected scintillation crystal is LeBr3(Ce

  4. 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.

  5. Fermiology of Ce2 Rh3 Ge5

    Science.gov (United States)

    Wartenbe, Mark

    The competition between localized and delocalized f electrons in heavy fermion materials produces a wide variety of interesting physical phenomena. Among these compounds is Ce2Rh3Ge5. This heavy-fermion system undergoes an antiferromagnetic transition below 4K and exhibits an angle dependent magnetic phase transition around 25 tesla. In addition, RF conductivity measurements in pulsed field (65T) have revealed quantum oscillations. Temperature dependence at fixed angle indicates relatively heavy effective masses of values ranging from ~3me on up to ~10me. This indicates that the narrow f-electron density of states is partially hybridized close to the Fermi energy, but also places strict cryogenic constraints upon the measurement (3Helium temperatures are required). Fermi surface calculations have produced complex figures which lend validation to such rich behavior. Presented are updated measurements including magnetization and revised theoretical calculations..

  6. 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…

  7. Two-orbital model for CeB6

    Science.gov (United States)

    Singh, Dheeraj Kumar

    2017-05-01

    We describe a two-orbital tight-binding model with bases belonging to the Γ8 quartet. It captures several characteristics of the Fermiology unravelled by the recent angle-resolved photoemission spectroscopic (ARPES) measurements on cerium hexaboride CeB6 samples cleaved along different high-symmetry crystallographic directions, which includes the ellipsoid-like Fermi surfaces (FSs) with major axes directed along Γ-X. We calculate various multipolar susceptibilities within the model and identify the susceptibility that shows the strongest divergence in the presence of standard onsite Coulomb interactions and discuss its possible implication and relevance with regard to the signature of strong ferromagnetic correlations existent in various phases as shown by the recent experiments.

  8. Table incremental slow injection CE-CT in lung cancer

    International Nuclear Information System (INIS)

    Yoshida, Shoji; Maeda, Tomoho; Morita, Masaru

    1988-01-01

    The purpose of this study is to evaluate tumor enhancement in lung cancer under the table incremental study with slow injection of contrast media. The early serial 8 sliced images during the slow injection (1.5 ml/sec) of contrant media were obtained. Following the early images, delayed 8 same sliced images were taken in 2 minutes later. Chacteristic enhanced patterns of the primary cancer and metastatic mediastinal lymphnode were recognized in this study. Enhancement of the primary lesion was classified in 4 patterns, irregular geographic pattern, heterogeneous pattern, homogeneous pattern and rim-enhanced pattern. In mediastinal metastatic lymphadenopathy, three enhanced patterns were obtained, heterogeneous, homogeneous and ring enhanced pattern. Some characteristic enhancement patterns according to the histopathological finding of the lung cancer were obtained. With using this incremental slow injection CE-CT, precise information about the relationship between lung cancer and adjacent mediastinal structure, and obvious staining patterns of the tumor and mediastinal lymphnode were recognized. (author)

  9. New limits on 2ε, εβ{sup +} and 2β{sup +} decay of {sup 136}Ce and {sup 138}Ce with deeply purified cerium sample

    Energy Technology Data Exchange (ETDEWEB)

    Belli, P.; Bernabei, R. [INFN Sezione Roma ' ' Tor Vergata' ' , Rome (Italy); Universita di Roma ' ' Tor Vergata' ' , Dipartimento di Fisica, Rome (Italy); Boiko, R.S. [Institute for Nuclear Research, Kyiv (Ukraine); National University of Life and Environmental Sciences of Ukraine, Kyiv (Ukraine); Cappella, F. [INFN Sezione Roma, Rome (Italy); Cerulli, R.; Laubenstein, M. [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Danevich, F.A.; Kropivyansky, B.N.; Polischuk, O.G.; Tretyak, V.I. [Institute for Nuclear Research, Kyiv (Ukraine); Incicchitti, A. [INFN Sezione Roma, Rome (Italy); Universita di Roma ' ' La Sapienza' ' , Dipartimento di Fisica, Rome (Italy); Mokina, V.M. [Institute for Nuclear Research, Kyiv (Ukraine); INFN Sezione Roma, Rome (Italy)

    2017-08-15

    A search for double electron capture (2ε), electron capture with positron emission (εβ{sup +}), and double positron emission (2β{sup +}) in {sup 136}Ce and {sup 138}Ce was realized with a 465 cm{sup 3} ultra-low background HP Ge γ spectrometer over 2299 h at the Gran Sasso underground laboratory. A 627 g sample of cerium oxide deeply purified by liquid-liquid extraction method was used as a source of γ quanta expected in double β decay of the cerium isotopes. New improved half-life limits were set on different modes and channels of double β decay of {sup 136}Ce and {sup 138}Ce at the level of T{sub 1/2} > 10{sup 17}-10{sup 18} yr. (orig.)

  10. Effect of Al deoxidation on the formation behavior of inclusions in Ce-added stainless steel melts

    Science.gov (United States)

    Kwon, Sun Kuk; Kong, Young-Min; Park, Joo Hyun

    2014-09-01

    The effect of Al deoxidation on the oxygen content and the inclusion properties (composition, size and morphology) of Ce-added stainless steel melts at 1873 K was investigated. The total oxygen content was about 310(±40) ppm before Al addition and slightly decreases with holding time when Al content was lower than 0.01%, whereas the oxygen content drastically decreased when Al content was greater than about 0.05%. Al content initially decreased, followed by an increase by addition of Ce, which originates from the reduction of Al2O3 in the refractory and/or inclusions by added Ce. The initial inclusions before Al addition were mainly Mn(Cr)-silicates. When Ce was added without Al deoxidation, small amounts of Ce oxide were detected after Ce addition. However, the content of Ce oxide decreased with holding time, and the inclusion composition reverted to the MnO-SiO2-Cr2O3 system. The initial Mn(Cr)-silicate inclusions transformed to Al2O3-rich inclusions by Al addition, and then Ce2O3 was enriched by Ce addition due to local enrichment of Ce around Al2O3 particles, resulting in the formation of AlCeO3-type inclusions. However, the Ce2O3 in the inclusions was continuously reduced by Al due to higher chemical potential of Al than Ce, finally forming the Al2O3-CeAl11O18 complex inclusions.

  11. Scintillation properties of Ce-doped LuLiF{sub 4} and LuScBO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Yanagida, Takayuki, E-mail: t_yanagi@tagen.tohoku.ac.jp [IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Fujimoto, Yutaka [IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Kawaguchi, Noriaki [IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Tokuyama Corporation, Shibuya 3-chome, Shibuya-ku, Tokyo 150-8383 (Japan); Yokota, Yuui [IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Kamada, Kei [Materials Research Laboratory, Furukawa, Co. Ltd., 1-25-13 Kannondai, Tsukuba, Ibaragi 305-0856 (Japan); Totsuka, Daisuke [Nihon Kessho Kogaku Co., Ltd., 810-5 Nobe-cho, Tatebayashi, Gunma 374-0047 (Japan); Hatamoto, Shun-Ichi [Corporate Research and Development Center, Mitsui Mining and Smelting Co., Ltd., 1333-2 Haraichi, Ageo Saitama 362-0023 (Japan); Yoshikawa, Akira; Chani, Valery [IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)

    2011-10-01

    The crystals of 1 mol% Ce-doped LuLiF{sub 4} (Ce:LLF) grown by the micro-pulling down ({mu}-PD) method and 1 mol% Ce-doped LuScBO{sub 3} (Ce:LSBO) grown by the conventional Czochralski (Cz) method were examined for their scintillation properties. Ce:LLF and Ce:LSBO demonstrated {approx}80% transparency at wavelengths longer than 300 and 400 nm, respectively. When excited by {sup 241}Am {alpha}-ray to obtain radioactive luminescence spectra, Ce{sup 3+} 5d-4f emission peaks were detected at around 320 nm for Ce:LLF and at around 380 nm for Ce:LSBO. In Ce:LSBO, the host luminescence was also observed at 260 nm. By recording pulse height spectra under {gamma}-ray irradiation, the absolute light yield of Ce:LLF and Ce:LSBO was measured to be 3600{+-}400 and 4200{+-}400 ph/MeV, respectively. Decay time kinetics was also investigated using a pulse X-ray equipped streak camera system. The main component of Ce:LLF was {approx}320 ns and that of Ce:LSBO was {approx}31 ns. In addition, the light yield non-proportionality and energy resolution against the {gamma}-ray energy were evaluated.

  12. Photoluminescence properties and energy-level diagrams in (Ce3+, Tb3+)-codoped KCl green phosphor

    International Nuclear Information System (INIS)

    Tosaka, Yuki; Adachi, Sadao

    2014-01-01

    KCl:Ce 3+ , Tb 3+ green phosphor was synthesized from an aqueous solution of KCl–CeCl 3 –TbCl 3 . The synthesized phosphor was investigated using X-ray diffraction analysis, electron probe microanalysis, diffuse reflectance measurements, photoluminescence (PL) analysis, PL excitation spectroscopy, and PL decay measurements. The KCl:Ce 3+ , Tb 3+ phosphor showed a strong Tb 3+ -related emission in the 480–700 nm spectral region. The Tb 3+ -related emission intensity in the codoped phosphor was enhanced more than 300 times compared to that in the Tb 3+ singly doped phosphor. This enhancement in the PL intensity could be attributed to an efficient energy transfer from Ce 3+ to Tb 3+ in the KCl host. The maximum transfer efficiency was η ∼92% for the sample synthesized at a solution of KCl:CeCl 3 :TbCl 3 =1:0.01:0.05 in molar ratio. The (Ce 3+ , Tb 3+ ) concentration dependences of the Ce 3+ - and Tb 3+ -emission decay times were determined. The temperature dependence of the Tb 3+ -related emission intensity was also measured and analyzed from T=20–450 K. - Highlights: • Simple method was developed for synthesizing KCl:Ce 3+ , Tb 3+ green phosphor. • Ce 3+ and Tb 3+ concentrations were optimized to obtain high efficient phosphor. • An efficient energy transfer was observed from Ce 3+ to Tb 3+ in KCl. • Detailed energy-level schemes for Ce 3+ and Tb 3+ ions in KCl were proposed

  13. Exposure of agricultural crops to nanoparticle CeO2in biochar-amended soil.

    Science.gov (United States)

    Servin, Alia D; De la Torre-Roche, Roberto; Castillo-Michel, Hiram; Pagano, Luca; Hawthorne, Joseph; Musante, Craig; Pignatello, Joseph; Uchimiya, Minori; White, Jason C

    2017-01-01

    Biochar is seeing increased usage as an amendment in agricultural soils but the significance of nanoscale interactions between this additive and engineered nanoparticles (ENP) remains unknown. Corn, lettuce, soybean and zucchini were grown for 28 d in two different soils (agricultural, residential) amended with 0-2000 mg engineered nanoparticle (ENP) CeO 2  kg -1 and biochar (350 °C or 600 °C) at application rates of 0-5% (w/w). At harvest, plants were analyzed for biomass, Ce content, chlorophyll and lipid peroxidation. Biomass from the four species grown in residential soil varied with species and biochar type. However, biomass in the agricultural soil amended with biochar 600 °C was largely unaffected. Biochar co-exposure had minimal impact on Ce accumulation, with reduced or increased Ce content occurring at the highest (5%) biochar level. Soil-specific and biochar-specific effects on Ce accumulation were observed in the four species. For example, zucchini grown in agricultural soil with 2000 mg CeO 2  kg -1 and 350 °C biochar (0.5-5%) accumulated greater Ce than the control. However, for the 600 °C biochar, the opposite effect was evident, with decreased Ce content as biochar increased. A principal component analysis showed that biochar type accounted for 56-99% of the variance in chlorophyll and lipid peroxidation across the plants. SEM and μ-XRF showed Ce association with specific biochar and soil components, while μ-XANES analysis confirmed that after 28 d in soil, the Ce remained largely as CeO 2 . The current study demonstrates that biochar synthesis conditions significantly impact interactions with ENP, with subsequent effects on particle fate and effects. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. Co-precipitation synthesis and characterization of NiO-Ce0.8Sm0.2O1.9 nanocomposite powders: effect of precipitation agents.

    Science.gov (United States)

    Ding, Changsheng; Lin, Hongfei; Sato, Kazuhisa; Hashida, Toshiyuki

    2011-03-01

    NiO-Ce0.8Sm0.2O1.9 (NiO-SDC) nanocomposite powders applied as promising anode material for low-temperature solid oxide fuel cells (SOFCs) were synthesized by hydroxide co-precipitation method using NH3 x H2O, NaOH and NH3 x H2O + NaOH as precipitation agents. The crystal phases, morphologies and sintering behavior of the synthesized NiO-SDC nanocomposite powders were investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and sintering experiments. The effect of precipitation agents on the synthesis of the NiO-SDC nanocomposite powders was discussed. Results show that different precipitation agents influence greatly the synthesis and characteristics of the NiO-SDC nanocomposite powders. The NiO-SDC nanocomposite powders synthesized with NH3 x H2O deviate from the original composition due to the loss of Ni. The loss of Ni is avoided and nano-sized NiO-SDC composite powders are synthesized, when NaOH and NH3 x H2O + NaOH are used as precipitation agents. The NiO-SDC nanocomposite powders can be synthesized at relatively low temperature using NH3 x H2O + NaOH as precipitation agent, and the synthesized NiO-SDC nanocomposite powders show good sintering characteristics.

  15. Muon spin relaxation study on itinerant ferromagnet CeCrGe₃ and the effect of Ti substitution on magnetism of CeCrGe₃.

    Science.gov (United States)

    Das, Debarchan; Bhattacharyya, A; Anand, V K; Hillier, A D; Taylor, J W; Gruner, T; Geibel, C; Adroja, D T; Hossain, Z

    2015-01-14

    A Muon spin relaxation (µSR) study has been performed on the Kondo lattice heavy fermion itinerant ferromagnet CeCrGe3. Recent investigations of bulk properties have revealed a long-range ordering of Cr moments at Tc = 70 K in this compound. Our µSR investigation between 1.2 K and 125 K confirm the bulk magnetic order which is marked by a loss in initial asymmetry below 70 K accompanied with a sharp increase in the muon depolarization rate. Field dependent µSR spectra show that the internal field at the muon site is higher than 0.25 T apparently due to the ferromagnetic nature of ordering. The effect of Ti substitution on the magnetism in CeCrGe3 is presented. A systematic study has been made on polycrystalline CeCr(1-x)Ti(x)Ge3 (0 ⩽ x ⩽ 1) using magnetic susceptibility χ(T), isothermal magnetization M(H), specific heat C(T) and electrical resistivity ρ(T) measurements which clearly reveal that the substitution of Ti for Cr in CeCrGe3 strongly influences the exchange interaction and ferromagnetic ordering of Cr moments. The Cr moment ordering temperature is suppressed gradually with increasing Ti concentration up to x = 0.50 showing Tc = 7 K beyond which Ce moment ordering starts to dominate and a crossover between Cr and Ce moment ordering is observed with a Ce moment ordering Tc = 14 K for x = 1.0. The Kondo lattice behavior is evident from temperature dependence of ρ(T) in all CeCr(1-x)Ti(x)Ge3 samples.

  16. Satellite line mapping in Eu3+–Ce3+ and Pr3+–Ce3+ codoped Y2SiO5

    International Nuclear Information System (INIS)

    Serrano, D.; Karlsson, J.; Zheng, L.; Dong, Y.; Ferrier, A.; Goldner, P.; Walther, A.; Rippe, L.; Kröll, S.

    2016-01-01

    In this work we perform a high-resolution spectroscopic investigation of Eu 3+ –Ce 3+ and Pr 3+ –Ce 3+ codoped Y 2 SiO 5 crystals. Satellite line spectra were recorded at low temperatures around the Eu 3+ : 7 F 0 → 5 D 0 and the Pr 3+ : 3 H 4 → 1 D 2 transitions. It is observed that the incorporation of Ce 3+ as a codopant notably changes the Eu 3+ and Pr 3+ satellite line patterns. Satellite lines measured in singly doped Eu 3+ :Y 2 SiO 5 were found at the same spectral positions in Eu 3+ –Ce 3+ codoped crystals. These coincident lines were concluded to be due to pairs of Eu 3+ ions. Extra satellite lines appeared in the codoped crystals, which were assigned to Ce 3+ related structures such as Ce 3+ –Eu 3+ pairs. The analysis of the Pr 3+ satellite line spectra presents further challenges. Satellite lines associated to Pr 3+ pairs show weaker intensity, presumably due to the efficient quenching of the Pr 3+1 D 2 emission through cross-relaxation paths ( 1 D 2 → 1 G 4 ; 3 H 4 → 3 F 4 ). The investigation of the Eu 3+ and Pr 3+ satellite line patterns in Y 2 SiO 5 is particularly interesting for their exploitation in rare-earth based quantum computation schemes. - Highlights: • We recorded Eu and Pr satellite lines in Y 2 SiO 5 with and without Ce as a codopant. • The presence of Ce leads to the appearance of extra satellite lines in the spectra. • The satellite lines are associated to minor crystal sites such as ion pairs. • Less than 100 ion pairs were detected per satellite line. • The exploitation of the satellite line structure is proposed for quantum computing.

  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. A facile synthesis of high quality nanostructured CeO2 and Gd2O3-doped CeO2 solid electrolytes for improved electrochemical performance.

    Science.gov (United States)

    Kuo, Yu-Lin; Su, Yu-Ming; Chou, Hung-Lung

    2015-06-07

    This study describes the use of a composite nitrate salt solution as a precursor to synthesize CeO2 and Gd2O3-doped CeO2 (GDC) nanoparticles (NPs) using an atmospheric pressure plasma jet (APPJ). The microstructures of CeO2 and GDC NPs were found to be cubical and spherical shaped nanocrystallites with average particle sizes of 10.5 and 6.7 nm, respectively. Reactive oxygen species, detected by optical emission spectroscopy (OES), are believed to be the major oxidative agents for the formation of oxide materials in the APPJ process. Based on the material characterization and OES observations, the study effectively demonstrated the feasibility of preparing well-crystallized GDC NPs by the APPJ system as well as the gas-to-particle mechanism. Notably, the Bader charge of CeO2 and Ce0.9Gd0.1O2 characterized by density function theory (DFT) simulation and AC impedance measurements shows that Gd helps in increasing the charge on Ce0.9Gd0.1O2 NPs, thus improving their conductivity and making them candidate materials for electrolytes in solid oxide fuel cells.

  19. Structural effects in the interstitial solid solution system (La,Ce)(Fe,Si)13Cx-H: Correlation with hydrogenation kinetics

    Science.gov (United States)

    Hai, X.; Porcher, F.; Mayer, C.; Miraglia, S.

    2018-02-01

    Steady state and in-situ neutron powder diffraction on selected compositions of the magneto-caloric (La,Ce)(Fe,Si)13CxHy compounds has been used to locate the sites accommodated by the interstitial species and to reveal the structural modifications (breathing) that occur upon metal substitution and/or interstitial insertion. The latter type of measurement in which the sequential filling of interstitial sites is followed allows one to extract some useful hydrogenation kinetics data. This structural investigation has allowed to precise the deformations undergone by the complex metallic alloys La(Fe,Si)13 when subjected to light interstitial insertion or rare earth substitution at the cation site of the NaZn13-structure type. We attempt to correlate hydrogenation kinetics variations (depression or enhancement of the hydrogen absorption rate) with a particular inhomogeneous cell variation (breathing) and bonding of the NaZn13 structure-type.

  20. Photocatalytic activity of Ce-modified SBA-15 for the degradation of ...

    Indian Academy of Sciences (India)

    als. Photocatalytic activity evaluation studies are made on all the samples for the degradation of isoproturon. Among them, 0.3 (wt%) Ce-modified Al-SBA-15 catalyst has shown a maximum activity in comparison with Ce-modified. SBA-15. The better activity is attributed to the synergistic effect of mesoporosity and the ...

  1. Toxicity of 144Ce inhaled in a relatively insoluble form by beagle dogs

    International Nuclear Information System (INIS)

    Boecker, B.B.; Hahn, F.F.; Muggenburg, B.A.; Mauderly, J.L.; McClellan, R.O.; Pickrell, J.A.

    1980-01-01

    The metabolism, dosimetry and effects of 144 Ce inhaled in fused aluminosilicate particles are being investigated in the beagle dog to assess the long-term biological consequences of release of relatively insoluble aerosol forms of 144 Ce that could occur in nuclear accidents. The effects resulting from the relatively protracted radiation dose patterns to the lung from this form of 144 Ce are being compared with effects of other radiation dose patterns to the lung. One hundred eleven dogs were exposed to aerosols of 144 Ce in fused aluminosilicate particles to yield initial lung burdens of 0.0024 to 210 μCi/kg body weight and 15 control dogs were exposed to nonradioactive fused aluminosilicate particles. To date, 65 144 Ce-exposed and 2 control dogs have died or were euthanized at 143 to 4578 days after inhalation of 144 Ce. Prominent findings in the 144 Ce-exposed dogs were radiation pneumonitis in 17 dogs that died at early times and neoplastic disease in 39 of the 48 dogs that died 750 days or later. Observations are continuing on the 46 144 Ce-exposed and 13 control dogs remaining alive at this time, at least 3337 days after exposure

  2. Toxicity of 144Ce inhaled in a relatively insoluble form by aged beagle dogs

    International Nuclear Information System (INIS)

    Boecker, B.B.; Hahn, F.F.; Muggenburg, B.A.; Mauderly, J.L.; McClellan, R.O.; Pickrell, J.A.

    1980-01-01

    The toxicity of relatively insoluble 144 Ce inhaled by 8- to 10.5-year-old beagle dogs is being investigated to provide information on possible age-related differences in the resulting long-term biological responses. Forty-two dogs were exposed, nose-only, to aerosols of 144 Ce in fused aluminosilicate particles to yield initial lung burdens of 2.2 to 75 μCi 144 Ce/kg body weight, and 12 control dogs were exposed to nonradioactive fused aluminosilicate particles. To date, 38 144 Ce-exposed dogs and 10 control dogs have died or were euthanized between 197 and 2375 days after inhalation of the 144 Ce. Prominent findings in the 144 Ce-exposed dogs were radiation pneumonitis in 19 dogs that died during the first 943 days post-exposure and neoplastic disease in seven of the 15 dogs. However, only one of these tumors killed the dog. No hemangiosarcomas have been observed in this study, although they were a prominent finding in immature or young adult dogs exposed to 144 Ce. Observations are continuing on the four surviving 144 Ce-exposed and two control dogs

  3. The influence of age on the retention of 141Ce in rats

    International Nuclear Information System (INIS)

    Kargachin, B.; Kostial, K.

    1988-01-01

    The influence of age on 141 Ce retention after oral and intraperitoneal administration was studied in 1 and 6-7 week-old rats. Older rats received 141 Ce orally by stomach tube while sucklings received it by the method of artificial feeding with a dropper. Retention of 141 Ce was determined in the whole body, carcass and organs (liver, bone, kidneys, brain, skin) 6, 12 and 18 days after 141 Ce intraperitoneal application, 6 and 12 days after oral application in sucklings and 1 day after oral application in older rats. Present results show higher values of retention in younger than in older rats both after oral and intraperitoneal 141 Ce administration. The whole body retention in sucklings 18 days after 141 Ce intraperitoneal administration was 1.4 times higher than in older animals. Retention was also significantly higher in skin, brain, bone, and kidneys. Age-related difference in retention was even more pronounced after 141 Ce oral administration. 141 Ce retention in younger animals was 2-3 orders of magnitude higher than in older ones. Present study once again indicates the importance of age in radionuclide metabolism. (author). 4 refs.; 1 tab

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  7. Charge dynamics in the Kondo insulator Ce3Bi4Pt3

    International Nuclear Information System (INIS)

    Bucher, B.; Schlesinger, Z.; Canfield, P.C.; Fisk, Z.

    1994-01-01

    We report the reflectivity and optical conductivity of the Kondo insulator Ce 3 Bi 4 Pt 3 . For temperatures less than 100 K, depletion of the conductivity below about 300 cm -1 signifies the development of a charge gap. The temperature dependence of the disappearance of the spectral weight scales with the quenching of the Ce 4f moments. ((orig.))

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  10. Spin-glass, antiferromagnetism and Kondo behavior in Ce2Au1 ...

    Indian Academy of Sciences (India)

    report high pressure electrical resistivity of Ce2AuSi3, ac susceptibility (χ) and magnetoresistance of various alloys of this solid solution in order to gain better knowledge of the magnetism of these alloys. High pressure resistivity behavior is consistent with the proposal that Ce2AuSi3 lies at the left-hand side of the maximum ...

  11. Structure of negative parity yrast bands in odd mass 125−131Ce ...

    Indian Academy of Sciences (India)

    4. — journal of. April 2010 physics pp. 525–539. Structure of negative parity yrast bands in odd mass 125−131Ce nuclei. ARUN BHARTI∗, SURAM SINGH and S K KHOSA. Department of ... in 125Ce have been extensively studied up to very high spins in recent years [3,4]. ... The detailed theory of PSM is given in [12].

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  15. Optical properties of pure and Ce3+ doped gadolinium gallium garnet crystals and epitaxial layers

    International Nuclear Information System (INIS)

    Syvorotka, I.I.; Sugak, D.; Wierzbicka, A.; Wittlin, A.; Przybylińska, H.; Barzowska, J.; Barcz, A.; Berkowski, M.; Domagała, J.; Mahlik, S.; Grinberg, M.; Ma, Chong-Geng

    2015-01-01

    Results of X-ray diffraction and low temperature optical absorption measurements of cerium doped gadolinium gallium garnet single crystals and epitaxial layers are reported. In the region of intra-configurational 4f–4f transitions the spectra of the bulk crystals exhibit the signatures of several different Ce 3+ related centers. Apart from the dominant center, associated with Ce substituting gadolinium, at least three other centers are found, some of them attributed to the so-called antisite locations of rare-earth ions in the garnet host, i.e., in the Ga positions. X-ray diffraction data prove lattice expansion of bulk GGG crystals due to the presence of rare-earth antisites. The concentration of the additional Ce-related centers in epitaxial layers is much lower than in the bulk crystals. However, the Ce-doped layers incorporate a large amount of Pb from flux, which is the most probable source of nonradiative quenching of Ce luminescence, not observed in crystals grown by the Czochralski method. - Highlights: • Ce 3+ multicenters found in Gadolinium Gallium Garnet crystals and epitaxial layers. • High quality epitaxial layers of pure and Ce-doped GGG were grown. • Luminescence quenching of Ce 3+ by Pb ions from flux detected in GGG epitaxial layers. • X-ray diffraction allows measuring the amount of the rare-earth antisites in GGG

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  17. Recent advances in CE-MS: Synergy of wet chemistry and instrumentation innovations.

    Science.gov (United States)

    Pantůčková, Pavla; Gebauer, Petr; Boček, Petr; Křivánková, Ludmila

    2011-01-01

    CE with MS detection is a hyphenated technique which greatly improves the ability of CE to deal with real samples, especially with those coming from biology and medicine, where the target analytes are present as trace amounts in very complex matrices. CE-MS is now almost a routine technique performed on commercially available instruments. It faces currently a tremendous development of the technique itself as well as of its wide application area. Great interest in CE-MS is reflected in the scientific literature by many original research articles and also by numerous reviews. The review presented here has a general scope and belongs to a series of regularly published reviews on the topic. It covers the literature from the last 2 years, since January 2008 till June 2010. It brings a critical selection of related literature sorted into groups reflecting the main topics of actual scientific interest: (i) innovations in CE-ESI-MS, (ii) use of alternative interfaces, and (iii) ways to enhance sensitivity. Special attention is paid to novel electrolyte systems amenable to CE-MS including nonvolatile BGEs, to advanced CE separation principles such as MEKC, MEEKC, chiral CE, and to the use of preconcentration techniques. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Novel nanostructured CeO 2 as efficient catalyst for energy and ...

    Indian Academy of Sciences (India)

    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 ...

  19. Alteration of steenstrupine-(Ce) from the Ilímaussaq alkaline complex, South Greenland

    DEFF Research Database (Denmark)

    Karup-Møller, Sven; Rose-Hansen, John

    2017-01-01

    Steenstrupine-(Ce) from two localities, Taseq and Mellemelv, both in the Ilímaussaq complex of South Greenland has been studied. At Taseq ussingite veins contain idiomorphic steenstrupine-(Ce) crystals with decomposed central parts, marginal zones of very thin rhythmically/oscillatory precipitate...

  20. Data of evolutionary structure change: 1CE7A-1OBSA [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1CE7A-1OBSA 1CE7 1OBS A A YERGDLDVTAQTTGAGYFSFITLLRDYVSSG-SFSNAIP...>1OBS A 1OBSA RLTTGADVRHE GLN CA 246 1OBS A 1OBSA...in>A 1OBSA ALYYYSTGGTQLPT ...n14> 1OBS A 1OBSA

  1. 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

    on the generation of an electric contact for both CE and ESI voltage through a narrow fracture close to the end of the CE capillary. The interface was mounted on a Nano ESI source of a hybrid Q-TOF instrument. To eliminate unwanted surface adsorption and/or interactions between polypeptide analytes and the inner...

  2. Ce que nous faisons | Page 46 | CRDI - Centre de recherches pour ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Le CRDI appuie des travaux de recherche dans les pays en voie de développement en vue de produire un changement réel et durable. Ce savoir peut servir d'outil pour résoudre des problèmes mondiaux urgents. Nous partageons ce savoir avec les autres en :

  3. Ce que nous faisons | Page 39 | CRDI - Centre de recherches pour ...

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  4. How BenMAP-CE Estimates the Health and Economic Effects of Air Pollution

    Science.gov (United States)

    The BenMAP-CE tool estimates the number and economic value of health impacts resulting from changes in air quality - specifically, ground-level ozone and fine particles. Learn what data BenMAP-CE uses and how the estimates are calculated.

  5. Facile synthesis of ferromagnetic Ni doped CeO2 nanoparticles with enhanced anticancer activity

    Science.gov (United States)

    Abbas, Fazal; Jan, Tariq; Iqbal, Javed; Ahmad, Ishaq; Naqvi, M. Sajjad H.; Malik, Maaza

    2015-12-01

    NixCe1-xO2 (where x = 0, 0.01, 0.03, 0.05 and 0.07) nanoparticles were synthesized by soft chemical method and were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, UV-vis absorption spectroscopy and vibrating sample magnetometer (VSM). XRD and Raman results indicated the formation of single phase cubic fluorite structure for the synthesized nanoparticles. Ni dopant induced excessive structural changes such as decrease in crystallite size as well as lattice constants and enhancement in oxygen vacancies in CeO2 crystal structure. These structural variations significantly influenced the optical and magnetic properties of CeO2 nanoparticles. The synthesized NixCe1-xO2 nanoparticles exhibited room temperature ferromagnetic behavior. Ni doping induced effects on the cytotoxicity of CeO2 nanoparticles were examined against HEK-293 healthy cell line and SH-SY5Y neuroblastoma cancer cell line. The prepared NixCe1-xO2 nanoparticles demonstrated differential cytotoxicity. Furthermore, anticancer activity of CeO2 nanoparticles observed to be significantly enhanced with Ni doping which was found to be strongly correlated with the level of reactive oxygen species (ROS) production. The prepared ferromagnetic NixCe1-xO2 nanoparticles with differential cytotoxic nature may be potential for future targeted cancer therapy.

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    International Development Research Centre (IDRC) Digital Library (Canada)

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  7. Synthesis of Mn-doped CeO2 nanorods and their application as ...

    Indian Academy of Sciences (India)

    as humidity sensors. C H HU, C H XIA. ∗. , F WANG, M ZHOU, P F YIN and X Y HAN. Science College of Chongqing Jiaotong University, Chongqing 400074, PR China. MS received 10 October 2010; revised 21 December 2010. Abstract. Mn-doped CeO2 nanorods have been prepared from CeO2 particles through a facile ...

  8. Preparation and properties of Pr 3/Ce 3: YAG phosphors using ...

    Indian Academy of Sciences (India)

    Keywords. Co-precipitation; YAG powder; phosphor; white-light LED; ceramic. Abstract. Pr 3 + /Ce 3 + :YAG precursors were co-precipitated using triethanolamine as dispersant and pH regulator. The different dosages of triethanolamine (D) vs. the properties of Pr 3 + /Ce 3 + :YAG phosphors were discussed. When D = 0.5 ...

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    International Development Research Centre (IDRC) Digital Library (Canada)

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  10. Preparation and characterization of Ce-doped ZnO nanofibers by an electrospinning method

    Directory of Open Access Journals (Sweden)

    Jong-Pil Kim

    2011-02-01

    Full Text Available ZnO and Ce-doped ZnO Nanofibers on (111 Pt/SiO2/Si substrates were produced using an electrospinning technique. The as-prepared composite fibres were subjected to high-temperature calcination to produce inorganic fibers. After calcining at a temperature of 500 °C, the average diameter of the ZnO and Ce-doped ZnO nanofibers were determined to be 170 nm and 225 nm, respectively. The average grain size of the ZnO and Ce-doped ZnO nanofibers were about 50 nm and 57 nm, respectively. The microstructure, chemical bonding state and photoluminescence of the produced ZnO and Ce-doped ZnO nanofibers were investigated. The Ce-doped ZnO nanofiber can be assigned to the presence of Ce ions on substitutional sites of Zn ions and the Ce3+ state from X-ray photoelectron spectra. Compared with PL spectra of ZnO nanofibers, the peak position of the UV emission of the Ce-doped ZnO nanofibers is sharply suppressed while the green emission band is highly enhanced.

  11. Preparation and characterization of Ce-doped HfO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Gálvez-Barboza, S. [Centro de Investigación en Química Aplicada, Departamento de Materiales Avanzados, Blvd. Enrique Reyna Hermosillo #140, C.P. 25294 Saltillo, Coahuila (Mexico); Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. Industria Metalúrgica # 1062 Parque Industrial, C.P. 25900 Ramos Arizpe, Coahuila (Mexico); González, L.A. [Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. Industria Metalúrgica # 1062 Parque Industrial, C.P. 25900 Ramos Arizpe, Coahuila (Mexico); Puente-Urbina, B.A.; Saucedo-Salazar, E.M. [Centro de Investigación en Química Aplicada, Departamento de Materiales Avanzados, Blvd. Enrique Reyna Hermosillo #140, C.P. 25294 Saltillo, Coahuila (Mexico); García-Cerda, L.A., E-mail: luis.garcia@ciqa.edu.mx [Centro de Investigación en Química Aplicada, Departamento de Materiales Avanzados, Blvd. Enrique Reyna Hermosillo #140, C.P. 25294 Saltillo, Coahuila (Mexico)

    2015-09-15

    Highlights: • Ce-doped HfO{sub 2} nanoparticles were prepared by a modified solgel method. • Ce-doped HfO{sub 2} nanoparticles have a semispherical shape with sizes between 6 and 11.5 nm. • The samples doped with 10% in weight of Ce directly crystallized in a cubic structure. • A quick, straightforward and effective route for the preparation of Ce-doped nanoparticles. - Abstract: A modified solgel method to synthesize Ce-doped HfO{sub 2} nanoparticles was carried out using a precursor material prepared with cerium nitrate, hafnium chloride, citric acid and ethylene glycol. The obtained precursor material was calcined at 500 and 700 °C for 2 h in air. The influence of the concentration of Ce and the calcination temperature was studied to observe the structural and morphological changes of the obtained materials. For the characterization, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman scattering (RS) were employed. The XRD patterns shown that the Ce-doped HfO{sub 2} undergoes a structural transformation from monoclinic to cubic phase, which is significantly dependent on the Ce content and calcination temperature. TEM images have also confirmed the existence of semispherical nanoparticles with sizes between 6 and 11.5 nm.

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  13. Ce3+-sensitized red Mn2+ luminescence in calcium aluminoborate phosphor material

    Science.gov (United States)

    Puchalska, M.; Zych, E.

    2017-12-01

    Ce3+ doped and Ce3+,Mn2+ co-doped calcium aluminoborate (CAB) phosphors were synthesised by solid-state reaction method and their optical properties were studied. X-ray powder diffraction, SEM and TEM studies indicated the crystallization of the main trigonal CaAl2B2O7 phase and the presence of an additional non-crystalline phase. It was also observed that increasing dopant concentration promotes phase separation. Hence, both series of phosphors demonstrated the changes in luminescence properties via activator concentration variation. Upon UV excitation (λex = 310 nm) Ce3+ doped and Ce3+,Mn2+ co-doped materials yielded intensive blue and pinkish luminescence, respectively. The spectra of CAB:Ce3+ samples showed a broad emission band due to 5d→4f transition of Ce3+, which broadened and shifted to longer wavelengths with increasing dopant content. Mn2+ co-doping caused appearance of another broad-band emission with a maximum of 680 nm, resulting from the 4T1(4G) →6A1(6S) transition of Mn2+. Detailed analysis of the emission and excitation spectra as well as decay time traces as a function of dopant concentration showed that efficient resonant energy transfer mainly occurs between Ce3+ and Mn2+ incorporated in the non-crystalline phase in CAB material. The estimated values of energy transfer efficiency of CAB:Ce3+(3%),Mn2+(4%) is close to 52%.

  14. Influence of microgravity on Ce-doped Bi12 SiO20 crystal defect

    Indian Academy of Sciences (India)

    TECS

    Abstract. 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 composi-.

  15. Ordering and Fluctuation of Quantum Multipoles in CeB6

    International Nuclear Information System (INIS)

    Shiina, R.

    2003-01-01

    The effect of multipolar fluctuations on the quadrupolar phase transition in CeB 6 is investigated theoretically. It is shown that the fluctuations become strong and field-dependent, reflecting the competition of coupled multipolar interactions. Some unusual phenomena around the transition in CeB 6 are shown to be reasonably explained within the RKKY model. (author)

  16. Contributing opportunistic resources to the grid with HTCondor-CE-Bosco

    Science.gov (United States)

    Weitzel, Derek; Bockelman, Brian

    2017-10-01

    The HTCondor-CE [1] is the primary Compute Element (CE) software for the Open Science Grid. While it offers many advantages for large sites, for smaller, WLCG Tier-3 sites or opportunistic clusters, it can be a difficult task to install, configure, and maintain the HTCondor-CE. Installing a CE typically involves understanding several pieces of software, installing hundreds of packages on a dedicated node, updating several configuration files, and implementing grid authentication mechanisms. On the other hand, accessing remote clusters from personal computers has been dramatically improved with Bosco: site admins only need to setup SSH public key authentication and appropriate accounts on a login host. In this paper, we take a new approach with the HTCondor-CE-Bosco, a CE which combines the flexibility and reliability of the HTCondor-CE with the easy-to-install Bosco. The administrators of the opportunistic resource are not required to install any software: only SSH access and a user account are required from the host site. The OSG can then run the grid-specific portions from a central location. This provides a new, more centralized, model for running grid services, which complements the traditional distributed model. We will show the architecture of a HTCondor-CE-Bosco enabled site, as well as feedback from multiple sites that have deployed it.

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  18. Scintillation and optical stimulated luminescence of Ce-doped CaF2

    International Nuclear Information System (INIS)

    Yanagida, Takayuki; Fujimoto, Yutaka; Watanabe, Kenichi; Fukuda, Kentaro; Kawaguchi, Noriaki; Miyamoto, Yuka; Nanto, Hidehito

    2014-01-01

    Scintillation and optical stimulated luminescence of Ce 0.1–20% doped CaF 2 crystals prepared by Tokuyama Corp. were investigated. In X-ray induced scintillation spectra, luminescence due to Ce 3+ 5d–4f transition appeared around 320 nm with typically 40 ns decay time. By 241 Am 5.5 MeV α-ray irradiation, 0.1% doped one showed the highest scintillation light yield and the light yield monotonically decreased with Ce concentrations. Optically stimulated luminescence after X-ray irradiation was observed around 320 nm under 550 or 830 nm stimulation in all samples. As a result, intensities of optically stimulated luminescence were proportional to Ce concentrations. Consequently, scintillation and optically stimulated luminescence resulted to have a complementary relation in Ce-doped CaF 2 system. - Highlights: • Optical, scintillation, and OSL properties of Ce 0.1–20% doped CaF 2 were studied. • Scintillation light yield exhibited inverse proportionality to Ce concentrations. • OSL intensities showed proportionality to Ce concentrations. • Complementary relation of scintillation and OSL was experimentally confirmed

  19. Influence of microgravity on Ce-doped Bi12 SiO20 crystal defect

    Indian Academy of Sciences (India)

    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 ...

  20. Desafios na gestão escolar

    Directory of Open Access Journals (Sweden)

    Flávia Obino Corrêa Werle

    2015-09-01

    Full Text Available Este estudo discute a avaliação em larga escala da educação básica, os processos de regulação e debate processos de gestão realizados no interior da escola pública. Seu objetivo é compreender como a equipe diretiva de duas escolas da rede pública estadual de Porto Alegre, Brasil, se apropria dos resultados do Indíce de Desenvolvimento da Educação Básica (IDEB e como lida com eles na gestão escolar. A metodologia utilizada é de cunho qualitativo com coleta de dados através de um questionário estruturado. Apresenta os resultados do IDEB das duas escolas no período de 2009 e 2011. Na prática escolar a apropriação ocorre em três dimensões (pedagógica, administrativa e participativa e promove diálogos em diferentes níveis: com a hierarquia do sistema educacional, com a comunidade externa à escola e, internamente, com os professores e demais membros da comunidade escolar.

  1. On the mechanism of nanoparticulate CeO{sub 2} toxicity to freshwater algae

    Energy Technology Data Exchange (ETDEWEB)

    Angel, Brad M., E-mail: Brad.Angel@csiro.au [Centre for Environmental Contaminants Research, CSIRO Land and Water Flagship, Locked Bag 2007, Kirrawee, NSW 2232 (Australia); Vallotton, Pascal [Digital Productivity Flagship, CSIRO, North Ryde, NSW 1670 (Australia); Apte, Simon C. [Centre for Environmental Contaminants Research, CSIRO Land and Water Flagship, Locked Bag 2007, Kirrawee, NSW 2232 (Australia)

    2015-11-15

    Highlights: • Nanoparticulate CeO{sub 2} less toxic than micron-sized CeO{sub 2}. • UV light filters prevented ROS generation by CeO{sub 2}. • ROS not toxic mechanism: CeO{sub 2} toxicity was similar in presence and absence of ROS. • Strong sorption of nanoparticulate CeO{sub 2} to Pseudokirchneriella subcapitata in synthetic fresh water. • CeO{sub 2} sorption to cells was prevented and toxicity mitigated in the presence of DOC. - Abstract: The factors affecting the chronic (72-h) toxicity of three nanoparticulate (10–34 nm) and one micron-sized form of CeO{sub 2} to the green alga, Pseudokirchneriella subcapitata were investigated. To characterise transformations in solution, hydrodynamic diameters (HDD) were measured by dynamic light scatter, zeta potential values by electrophoretic mobility, and dissolution by equilibrium dialysis. The protective effects of humic and fulvic dissolved organic carbon (DOC) on toxicity were also assessed. To investigate the mechanisms of algal toxicity, the CytoViva hyperspectral imaging system was used to visualise algal–CeO{sub 2} interactions in the presence and absence of DOC, and the role of reactive oxygen species (ROS) was investigated by ‘switching off’ ROS production using UV-filtered lighting conditions. The nanoparticulate CeO{sub 2} immediately aggregated in solution to HDDs measured in the range 113–193 nm, whereas the HDD and zeta potential values were significantly lower in the presence of DOC. Negligible CeO{sub 2} dissolution over the time course of the bioassay ruled out potential toxicity from dissolved cerium. The nanoparticulate CeO{sub 2} concentration that caused 50% inhibition of algal growth rate (IC50) was in the range 7.6–28 mg/L compared with 59 mg/L for micron-sized ceria, indicating that smaller particles were more toxic. The presence of DOC mitigated toxicity, with IC50s increasing to greater than 100 mg/L. Significant ROS were generated in the nanoparticulate CeO{sub 2

  2. CeCo5 thin films with perpendicular anisotropy grown by molecular beam epitaxy

    Science.gov (United States)

    Sharma, S.; Hildebrandt, E.; Major, M.; Komissinskiy, P.; Radulov, I.; Alff, L.

    2018-04-01

    Buffer-free, highly textured (0 0 1) oriented CeCo5 thin films showing perpendicular magnetic anisotropy were synthesized on (0 0 1) Al2O3 substrates by molecular beam epitaxy. Ce exists in a mixture of Ce3+ and Ce4+ valence states as shown by X-ray photoelectron spectroscopy. The first anisotropy constant, K1, as measured by torque magnetometry was 0.82 MJ/m3 (8.2 ×106erg /cm3) . A maximum coercivity of 5.16 kOe with a negative temperature coefficient of -0.304%K-1 and a magnetization of 527.30 emu/cm3 was measured perpendicular to the film plane at 5 K. In addition, a large anisotropy of the magnetic moment of 15.5% was observed. These magnetic parameters make CeCo5 a potential candidate material for spintronic and magnetic recording applications.

  3. The magnetic properties of Ce/Pd surface alloys investigated using DFT

    KAUST Repository

    Shuttleworth, I.G.

    2014-06-01

    The surface alloys that form between Ce and Pd(1 1 1), Pd(1 0 0) and both unreconstructed and missing-row type Pd(1 1 0) at low Ce coverage ( θCe=19ML) have shown permanent magnetism that is mediated in part by an RKKY-like delocalized Ce 6s-Pd 5s interaction. The Pd 4d states are significantly affected by alloying and their behavior cannot be explained by a purely spin-dependent Hamiltonian. Experimental observations of changes to the Pd 4d states are explained and the implications of Ce/Pd magnetism in reforming catalysis are discussed. © 2014 Elsevier B.V. All rights reserved.

  4. Numerical simulation of shock wave dynamics and detonation phenomena with using improved CE/SE method

    International Nuclear Information System (INIS)

    Zhang, D.-L.

    2005-01-01

    The space-time conservation element and solution element (CE/SE) method is a new numerical method to solve the equations of conservation laws in fluid dynamics. It differs substantially in both concept and methodology from the current numerical methods. It has some marked advantages: generality, simple, high efficiency, high resolution and enforcing flux conservation strictly in space and time. In this paper the CE/SE method has been improved. The improved CE/SE method was applied into the interaction of shock wave and detonation with vortex. Several numerical examples were given. Numerical results of improved CE/SE method were compared with the results of experiments and other computational method. The compared results have showed that the improved CE/SE method is a more prospective scheme. (author)

  5. Theoretical study of Ce2+ cubic centres in alkaline earth fluoride crystals

    International Nuclear Information System (INIS)

    Popov, N.; Mysovsky, A.; Shendrik, R.; Radzhabov, E.

    2016-01-01

    In this paper we present theoretical study of Ce 2+ impurity centres in alkaline earth fluoride crystals (CaF 2 , SrF 2 ). Only cubic configurations of centres were considered. Electronic levels and related properties were studied using CASSCF/CASPT2 approach within embedded-cluster formalism including scalar relativistic corrections and spin-orbital interaction. Calculated absorption spectra for Ce 2+ in CaF 2 and SrF 2 are in good agreement with experimental data. For both crystals the ground state of Ce 2+ ion has predominantly 4f 1 5d 1 singlet character. - Highlights: • Ab inito study of Ce 2+ impurity centres in alkaline earth fluoride crystals. • Calculated Ce 2+ ground state in CaF 2 and SrF 2 is predominantly 4f 1 5d 1 singlet. • Calculated absorption spectra are in good agreement width experimental data.

  6. Preparation of nanosized yttrium doped CeO2 catalyst used for photocatalytic application

    Directory of Open Access Journals (Sweden)

    A. Akbari-Fakhrabadi

    2015-09-01

    Full Text Available In the present work, the pure CeO2 and yttrium doped CeO2 nanopowders were synthesized by the nitrate-fuel self-sustaining combustion method and calcined at 700 °C for 2 h. X-ray diffraction (XRD and high resolution electron transmission microscopy (HRTEM results demonstrated a cubic fluorite with high purity and the crystallite sizes less than 20 nm calculated from Scherrer’s formula. The BET specific surface area of yttrium doped CeO2 samples showed high values than those of pure CeO2. The photocatalytic activity of yttrium doped CeO2 showed high degradation of Rhodamine B solution under visible light illumination.

  7. Relationship between Microstructure and Properties of Cu-Cr-Ag-(Ce) Alloy Using Microscopic Investigation.

    Science.gov (United States)

    Chen, Huiming; Yuan, Dawei; Wu, Shanjiang; Wang, Hang; Xie, Weibin; Yang, Bin

    2017-01-01

    Microstructure, precipitation hardening response, and mechanical and physical properties of Cu-Cr-Ag alloy and Cu-Cr-Ag-Ce alloy have been investigated using transmission electron microscopy, scanning electron microscope, optical microscope, electrical conductivity analysis, and tensile test. The influence of element Ce on the matrix refinement, impurity removal, and precipitation in the Cu-Cr-Ag alloys has been analyzed. The experimental results show that the strength and electrical conductivity of Ce containing alloys are greater than those of Ce-free alloys after each processing step. Improvement of strength and electrical conductivity of the Cu-Cr-Ag alloy by adding Ce element is attributed to removing oxygen and sulfur from as-cast alloy.

  8. NA60 Status Report

    CERN Document Server

    Usai, G

    2010-01-01

    This report shortly summarizes the main results obtained from the analysis of the NA60 data during 2010, perspectives for the analysis activity during 2011 and the requests to CERN following from them. In addition, renewed interest is expressed for a possible continuation of NA60, including future running at lower SPS energies.

  9. Inverse CeO2sbnd Fe2O3 catalyst for superior low-temperature CO conversion efficiency

    Science.gov (United States)

    Luo, Yongming; Chen, Ran; Peng, Wen; Tang, Guangbei; Gao, Xiaoya

    2017-09-01

    The paper presents a rational design of highly efficient and affordable catalysts for CO oxidation with a low operating temperature. A series of ceria-iron catalysts were inversely built via a co-precipitation method. The catalytic activity of low-temperature CO oxidation was much higher with CeO2-modified Fe2O3 (CeO2sbnd Fe2O3) than with Fe2O3-modified CeO2 (Fe2O3sbnd CeO2). In particular, the 7.5% CeO2sbnd Fe2O3 catalyst had the highest activity, reaching 96.17% CO conversion at just 25 °C. Catalyst characterization was carried out to explore the cause of the significantly different CO conversion efficiencies between the Fe2O3sbnd CeO2 and Fe2O3sbnd CeO2 catalysts. HRTEM showed a significant inhomogeneous phase in 7.5% CeO2sbnd Fe2O3 with small CeO2 nanoparticles highly dispersed on the rod-shaped Fe2O3 surface. Furthermore, the 7.5% CeO2sbnd Fe2O3 composite catalyst exhibited the highest ratios of Fe2+/Fe3+ and Ce3+/Ce4+ as well as the largest pore volume. These properties are believed to benefit the CO conversion in 7.5% CeO2sbnd Fe2O3.

  10. Luminescent properties of Y3Al5−xGaxO12:Ce crystals

    International Nuclear Information System (INIS)

    Zorenko, Yu.; Zorenko, T.; Malinowski, P.; Sidletskiy, O.; Neicheva, S.

    2014-01-01

    Absorption, luminescent and scintillation properties of Ce 3+ doped Y 3 Al 5−x Ga x O 12 crystals with Ga content in the x=1–5 range were investigated in this work and compared with the properties of YAG:Ce crystals. Apart from the traditional spectral methods (absorption, cathodoluminescence and light yield measurements), the intrinsic and Ce 3+ related luminescence of Y 3 Al 5−x Ga x O 12 :Ce solid-solution were also investigated using the luminescent spectroscopy under excitation by synchrotron radiation in the 3.7–25 eV range. We show that the optical properties Y 3 Al 5−x Ga x O 12 :Ce garnets monotonically change with increasing the Ga content in the x=0–3 range due to preferable localization of Ga ions in the tetrahedral position of the garnet lattice. At the highest Ga concentration (x>3) the deviation of the optical properties of Y 3 Al 5−x Ga x O 12 :Ce garnets is observed from the respective properties of these crystals with Ga content in the x=0–3 range due to occupation by Ga ions of the octahedral position in the garnet host. - Highlights: • Different dependence of optical properties of Y 3 Al 5−x Ga x O 12 :Ce crystals on Ga content in x=0–3 and 3–5 ranges. • Elimination of the luminescence of Y Al antisite defects in Y 3 Al 5−x Ga x O 12 :Ce crystals at x>2. • Significant improvement of the scintillation properties of Y 3 Al 5−x Ga x O 12 :Ce crystals at x=2 and 3 in comparison with YAG:Ce

  11. Incommensurate and commensurate magnetic structures of the ternary germanide CeNiGe3

    International Nuclear Information System (INIS)

    Durivault, L; Bouree, F; Chevalier, B; Andre, G; Weill, F; Etourneau, J; Martinez-Samper, P; Rodrigo, J G; Suderow, H; Vieira, S

    2003-01-01

    The structural properties of CeNiGe 3 have been investigated via electron diffraction and neutron powder diffraction (NPD). This ternary germanide crystallizes in the orthorhombic SmNiGe 3 -type structure (Cmmm space group). Electrical resistivity, ac- and dc-magnetization measurements show that CeNiGe 3 orders antiferromagnetically below T N = 5.5(2) K and exclude the occurrence at low temperatures of a spin-glass state for CeNiGe 3 as previously reported. Specific heat measurements and NPD both reveal two magnetic transitions, observed at T N1 = 5.9(2) K and T N2 = 5.0(2) K. Between T N1 and T N2 , the Ce magnetic moments in CeNiGe 3 are ordered in a collinear antiferromagnetic structure associated with the k 1 = (100) wavevector and showing a relationship with the magnetic structure of the Ce 3 Ni 2 Ge 7 ternary germanide. Below T N2 , this k 1 = (100) commensurate magnetic structure coexists with an incommensurate helicoidal magnetic structure associated with k 2 = (00.409(1)1/2). This last magnetic structure is highly preponderant below T N2 (93(5)% in volume). At 1.5 K, the Ce atoms in CeNiGe 3 carry a reduced ordered magnetic moment (0.8(2) μ B ). This value, smaller than that obtained in Ce 3 Ni 2 Ge 7 , results from an important hybridization of the 4f(Ce) orbitals with those of the Ni and Ge ligands

  12. Facile synthesis of ferromagnetic Ni doped CeO{sub 2} nanoparticles with enhanced anticancer activity

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Fazal; Jan, Tariq [Laboratory of Nanoscience and Technology, Department of Physics, International Islamic University Islamabad (Pakistan); Iqbal, Javed, E-mail: javed.saggu@iiu.edu.pk [Laboratory of Nanoscience and Technology, Department of Physics, International Islamic University Islamabad (Pakistan); Ahmad, Ishaq [Experimental Physics Labs, National Center for Physics, Islamabad (Pakistan); Naqvi, M. Sajjad H. [Department of Biochemistry, University of Karachi, Karachi (Pakistan); Malik, Maaza [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa)

    2015-12-01

    Highlights: • The synthesized undoped and Ni doped CeO{sub 2} nanoparticles exhibited RTFM. • Oxygen vacancies and magnetic ions both were believed to be responsible for RTFM. • The prepared nanoparticles exhibited selective cytotoxicity. • Ni doping enhanced the anticancer activity of CeO{sub 2} nanoparticles. • Differential ROS generation was observed to control their cytotoxicity. - Abstract: Ni{sub x}Ce{sub 1−x}O{sub 2} (where x = 0, 0.01, 0.03, 0.05 and 0.07) nanoparticles were synthesized by soft chemical method and were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, UV–vis absorption spectroscopy and vibrating sample magnetometer (VSM). XRD and Raman results indicated the formation of single phase cubic fluorite structure for the synthesized nanoparticles. Ni dopant induced excessive structural changes such as decrease in crystallite size as well as lattice constants and enhancement in oxygen vacancies in CeO{sub 2} crystal structure. These structural variations significantly influenced the optical and magnetic properties of CeO{sub 2} nanoparticles. The synthesized Ni{sub x}Ce{sub 1−x}O{sub 2} nanoparticles exhibited room temperature ferromagnetic behavior. Ni doping induced effects on the cytotoxicity of CeO{sub 2} nanoparticles were examined against HEK-293 healthy cell line and SH-SY5Y neuroblastoma cancer cell line. The prepared Ni{sub x}Ce{sub 1−x}O{sub 2} nanoparticles demonstrated differential cytotoxicity. Furthermore, anticancer activity of CeO{sub 2} nanoparticles observed to be significantly enhanced with Ni doping which was found to be strongly correlated with the level of reactive oxygen species (ROS) production. The prepared ferromagnetic Ni{sub x}Ce{sub 1−x}O{sub 2} nanoparticles with differential cytotoxic nature may be potential for future targeted cancer therapy.

  13. A cidade como lugar de conflito: as práticas de violência e civilização no cotidiano de Senador Pompeu – CE (1901-1930 = The city as a place of conflict: the practice of violence and civilization in daily life in Senador Pompeu - CE (1901-1930

    Directory of Open Access Journals (Sweden)

    Oliveira, Lucas Pereira de

    2014-01-01

    Full Text Available Pensar as práticas de violência e civilização nas cidades e como elas se deram no decorrer do percurso histórico são essenciais para refletirmos a sociedade na qual habitamos, seus desejos, conflitos, medos e aspirações. Desta feita, na tentativa de compreender suas relações é que se insere esta pesquisa, na busca por analisar o cotidiano (CERTEAU, por hora violento e por hora civilizado da cidade de Senador Pompeu/CE, cidade do sertão cearense, nas primeiras três décadas do século XX. Este ensaio faz parte de inquietações da dissertação de Mestrado em curso. Buscaremos refletir até que ponto o processo de civilização (ELIAS, através da normatização do Estado (leis/convenções/normas, auxiliou ou não redução dos instintos violentos (DA MATTA dos indivíduos na sociedade e na transformação de seus hábitos e costumes (THOMPSON. Essencialmente utilizamos como fonte para esta pesquisa as Ações Criminais encontradas no Fórum Dr. Francisco Barros Gomes em Senador Pompeu-CE. Utilizaremos também os Códigos de Posturas, Código Penal, Livros de Protocolos, Tombos, Atas de julgamentos e os Jornais de veiculação do recorte temporal. Apoiados numa relação de interdisciplinaridade entre história, sociologia e direito, buscamos discutir e problematizar o fenômeno da violência dentro do cotidiano de práticas da cidade de Senador Pompeu-CE. Dessa forma, historiadores dentro de suas possibilidades, sempre buscam trabalhar com questões que os inquietam e com os anseios da sociedade em que faz parte, na busca por identificar, traduzir e resignificar as ações dos homens no tempo

  14. The effect of Ce ion substituted OMS-2 nanostructure in catalytic activity for benzene oxidation

    Science.gov (United States)

    Hou, Jingtao; Li, Yuanzhi; Mao, Mingyang; Zhao, Xiujian; Yue, Yuanzheng

    2014-11-01

    The nanostructure of Ce doped OMS-2 plays a very important role in its catalytic property. We demonstrate by density functional theory (DFT) calculations that the unique nanostructure of the Ce ion substituted OMS-2 with Mn vacancy in the framework is beneficial for the improvement of catalytic activity, while the nanostructure of the Ce ion substituted OMS-2 without defects are detrimental to the catalytic activity. We establish a novel and facile strategy of synthesizing these unique Ce ion substituted OMS-2 nanostructure with Mn vacancies in the framework by hydrothermal redox reaction between Ce(NO3)3 and KMnO4 with KMnO4/Ce(NO3)3 at a molar ratio of 3 : 1 at 120 °C. Compared to pure OMS-2, the produced catalyst of Ce ion substituted OMS-2 ultrathin nanorods exhibits an enormous enhancement in the catalytic activity for benzene oxidation, which is evidenced by a significant decrease (ΔT50 = 100 °C, ΔT90 = 129 °C) in the reaction temperature of T50 and T90 (corresponding to the benzene conversion = 50% and 90%), which is considerably more efficient than the expensive supported noble metal catalyst (Pt/Al2O3). We combine both theoretical and experimental evidence to provide a new physical insight into the significant effect due to the defects induced by the Ce ion substitution on the catalytic activity of OMS-2. The formation of unique Ce ion substituted OMS-2 nanostructure with Mn vacancies in the framework leads to a significant enhancement of the lattice oxygen activity, thus tremendously increasing the catalytic activity.The nanostructure of Ce doped OMS-2 plays a very important role in its catalytic property. We demonstrate by density functional theory (DFT) calculations that the unique nanostructure of the Ce ion substituted OMS-2 with Mn vacancy in the framework is beneficial for the improvement of catalytic activity, while the nanostructure of the Ce ion substituted OMS-2 without defects are detrimental to the catalytic activity. We establish a novel

  15. Aqueous and Surface Chemistries of Photocatalytic Fe-Doped CeO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Duangdao Channei

    2017-01-01

    Full Text Available The present work describes the effects of water on Fe-doped nanoparticulate CeO2, produced by flame spray pyrolysis, which is a critical environmental issue because CeO2 is not stable in typical atmospheric conditions. It is hygroscopic and absorbs ~29 wt % water in the bulk when exposed to water vapor but, more importantly, it forms a hydrated and passivating surface layer when immersed in liquid water. In the latter case, CeO2 initially undergoes direct and/or reductive dissolution, followed by the establishment of a passivating layer calculated to consist of ~69 mol % solid CeO2·2H2O and ~30 mol % gelled Ce(OH4. Under static flow conditions, a saturated boundary layer also forms but, under turbulent flow conditions, this is removed. While the passivating hydrated surface layer, which is coherent probably owing to the continuous Ce(OH4 gel, would be expected to eliminate the photoactivity, this does not occur. This apparent anomaly is explained by the calculation of (a the thermodynamic stability diagrams for Ce and Fe; (b the speciation diagrams for the Ce4+-H2O, Ce3+-H2O, Fe3+-H2O, and Fe2+-H2O systems; and (c the Pourbaix diagrams for the Ce-H2O and Fe-H2O systems. Furthermore, consideration of the probable effects of the localized chemical and redox equilibria owing to the establishment of a very low pH (<0 at the liquid-solid interface also is important to the interpretation of the phenomena. These factors highlight the critical importance of the establishment of the passivating surface layer and its role in photocatalysis. A model for the mechanism of photocatalysis by the CeO2 component of the hydrated phase CeO2·2H2O is proposed, explaining the observation of the retention of photocatalysis following the apparent alteration of the surface of CeO2 upon hydration. The model involves the generation of charge carriers at the outer surface of the hydrated surface layer, followed by the formation of radicals, which decompose organic

  16. Regulamin rezerwatu. O książce "Jewish Poland Revisited" Eriki Lehrer

    Directory of Open Access Journals (Sweden)

    Konrad Matyjaszek

    2016-01-01

    social and spatial.   Regulamin rezerwatu. O książce Jewish Poland Revisited Eriki Lehrer Artykuł stanowi recenzję książki Jewish Poland Revisited Eriki Lehrer, prezentującej wyniki antropologicznych badań na temat żydowsko-polskich projektów pamięci realizowanych w byłej dzielnicy żydowskiej na krakowskim Kazimierzu. Omawiając tezy pracy, autor poddaje krytycznej analizie proponowany przez Lehrer projekt etnografii możliwości i wynikającą z niego strategię akceptacji współczesnego Kazimierza jako przestrzeni spotkania, za którą idzie akceptacja zasad uczestnictwa narzuconych gościom przez polskich zarządców Kazimierza. W artykule rozpatrywane są dwie takie zasady, warunkujące możliwość uczestnictwa gościa w kurczącej się przestrzeni publicznej Kazimierza. Pierwszą z nich autor opisuje jako nakaz porzucenia bezpośrednio dostępnej, fizycznej przestrzeni dzielnicy i niesionych przez nią historii, których znakiem jest ocalała zabudowa. W to miejsce Lehrer wprowadza podział na przestrzeń społeczną i fizyczną, skutkiem czego stłumione zostają ślady brutalnej przeszłości, w przeciwnym razie bezpośrednio obecne. Drugą zasadę autor odtwarza jako wymóg akceptacji roli współczesnych polskich właścicieli jako brokerów i pośredników żydowskiego dziedzictwa, co w konsekwencji pociąga za sobą akceptację ich wątpliwych prawnie i moralnie roszczeń do zawłaszczonej przestrzeni. Skupienie uwagi na regulaminie uczestnictwa, który ustanawia i utrzymuje warunkowy charakter żydowskiej obecności w przestrzeni Kazimierza, prowadzi autora do wniosku o konieczności rewaluacji i redefinicji tradycyjnego rozdziału dyscyplin, który tworzy konceptualny podział na społeczne przestrzenie i architektoniczne obiekty, oraz do krytycznego namysłu nad obowiązującym obecnie w Europie Środkowo-Wschodniej rozumieniem pojęcia „dziedzictwo”. Tego rodzaju poszukiwanie uznaje autor za warunek przezwyciężenia ignorowanego zwykle

  17. Postępowanie w sprawie skargi na ogłoszenie organizatora o woli bezpośredniego zawarcia umowy w ustawie o publicznym transporcie zbiorowym

    OpenAIRE

    Rozczyński, Beniamin

    2017-01-01

    Niniejszy artykuł ma na celu poruszenie problematyki związanej z istotną dziedziną życia publicznego, jaką jest transport publiczny. Zaprezentowano w nim badania dotyczące prawnych regulacji związanych z publicznym transportem zbiorowym, w szczególności na poziomie lokalnym. Autor skupił się na problematyce związanej z postępowaniem w sprawie skargi na ogłoszenie organizatora o woli bezpośredniego zawarcia umowy. W pierwszej kolejności przedstawiono podstawowe regulacje prawne związane z p...

  18. ExoDat Information System at CeSAM

    Science.gov (United States)

    Agneray, F.; Moreau, C.; Chabaud, P.; Damiani, C.; Deleuil, M.

    2014-05-01

    CoRoT (Convection Rotation and planetary transits) is a space based mission led by French space agency (CNES) in association with French and international laboratories. One of CoRoT's goal is to detect exoplanets by the transit method. The Exoplanet Database (Exodat) is a VO compliant information system for the CoRoT exoplanet program. The main functions of ExoDat are to provide a source catalog for the observation fields and targets selection; to characterize the CoRoT targets (spectral type, variability , contamination...);and to support follow up programs. ExoDat is built using the AstroNomical Information System (ANIS) developed by the CeSAM (Centre de donneeS Astrophysique de Marseille). It offers download of observation catalogs and additional services like: search, extract and display data by using a combination of criteria, object list, and cone-search interfaces. Web services have been developed to provide easy access for user's softwares and pipelines.

  19. Superconductivity without inversion symmetry in CePt3Si

    International Nuclear Information System (INIS)

    Frigeri, P.A.; Agterberg, D.F.; Koga, A.; Sigrist, M.

    2005-01-01

    Based on symmetry arguments by Anderson, the following conditions are necessary for the formation of Cooper pairs: spin-singlet pairing relies on time-reversal symmetry, while spin-triplet pairing requires parity in addition. The rather general formulation of this rule has led to the common belief that the lack of an inversion center in a material would prevent spin-triplet pairing indiscriminately. In this presentation, we discuss symmetry aspects of superconductivity in a class of systems without inversion symmetry which is connected with spin-orbit coupling. We can show that, not only spin singlet pairing, but also certain spin triplet states remain unaffected by the loss of inversion symmetry. Moreover, the absence of an inversion center reduces the effect of paramagnetic limiting for spin-singlet pairing states in an external magnetic field. Based on this symmetry analysis, we examine the recently discovered heavy Fermion superconductor CePt 3 Si, where a missing inversion plane leads to the well-known Rashba-type of spin-orbit coupling. In particular, the problem of the pairing symmetry will be addressed as well as several properties of the superconducting phase which appears close to a quantum phase transition between a paramagnetic and antiferromagnetic phase. The same kind of analysis will also be done for another example UIr

  20. Microchips for CE: breakthroughs in real-world food analysis.

    Science.gov (United States)

    Escarpa, Alberto; González, María Cristina; López Gil, Miguel Angel; Crevillén, Agustín G; Hervás, Miriam; García, Miguel

    2008-12-01

    The well-known complexity of food matrices is approached using CE microchips with different strategies to improve the selectivity and sensitivity of the analysis by avoiding and/or making the sample preparation as simple as possible: (i) enhancing the peak capacity in order to perform direct injection, (ii) using the microchip platform to measure one target analyte/group of analytes with or without separating other related interferences, (iii) integrating sample preparation steps on the microchip platform, and (iv) integrating new analytical tools from nanotechnology in the detection stage. New analyte separations of food significance involving DNA probes, biogenic amines, vanilla flavors, and dyes have been reported as successfully breaking new barriers in areas of high impact in the market, such as transgenic food analysis, as well as the detection of frauds and toxins. Simple microchip layouts are still the most common designs used, though sophisticated new ones are emerging. In contrast to other application areas, electrochemical detection continues to be the most common detection route, followed by LIF, though non-conventional detection routes are also emerging, such as chemiluminescence or UV. In terms of analytical performance, the integration of calibration and quality control on a microchip platform, and remarkable accuracy and precision are being obtained using creative analytical methodologies that enhance the analytical potency of microfluidic chips for their future commercialization. This review critically states the most important advances derived from work done in the field over the past 2-3 years.

  1. Breastfeeding practices in the city of Iguatu-CE

    Directory of Open Access Journals (Sweden)

    Lúcia Vanda Teixeira de Freitas Cavalcante

    2012-12-01

    Full Text Available Objective: To assess breastfeeding practices in Family Health Strategy. Methods: A descriptive cross-sectional quantitative study conducted in Family Health Units of the urban area of Iguatu-CE, Brazil, from August 2008 to May 2009. Participants were 402 mothers with children under six months of age who underwent prenatal consultations. We used a form with questions regarding breastfeeding, breastfeeding difficulties, introducing other foods, infant nutrition, consultations prenatal and postpartum visits undertaken by staff. The data were entered into SPSS 16.0 and analyzed descriptively. Results: Among the mothers interviewed (402, most said that was breastfeeding babies (N = 343, 85.3%, but introduced other food (N = 252, 62.6%, verifying low prevalence of exclusive breastfeeding. Of the 252 women who reported offering other food to baby, 158 (62.7% offered on their own, followed by those who chose to follow the indication of relatives and neighbors (N = 63, 25%. Conclusions: The study revealed that mothers of the Family Health Units from Iguatu-EC did not breastfeed their children exclusively, but with the introduction of other foods (other milk, porridge, thereby demonstrating the low prevalence of exclusive breastfeeding.

  2. Development of microcolumnar LaBr3:Ce scintillator

    Science.gov (United States)

    Nagarkar, Vivek V.; Miller, Stuart; Singh, Bipin; Thacker, Samta; Gaysinskiy, Valeriy; Miller, Brian W.; Barber, H. Bradford; Wilson, Donald

    2009-08-01

    While a wide variety of new scintillators are now available, new cerium-doped lanthanide halide scintillators have shown a strong potential to move beyond their familiar role in conventional gamma ray spectroscopy, toward fulfilling the needs of highly demanding applications such as radioisotope identification at room temperature, homeland security, and quantitative molecular imaging for medical diagnostics, staging and research. Despite their extraordinary advantages, however, issues related to reliable, large volume manufacturing of these high light yield materials in a rapid and economic manner have not been resolved or purposefully addressed. Also, if microcolumnar films of this material could be fabricated, it would find widespread use in a multitude of high-speed imaging/nuclear medicine applications. Here we report on synthesizing LaBr3:Ce scintillators using a thermal evaporation technique, which permits the fabrication of high spatial resolution microcolumnar films and holds a potential to synthesize large volumes of high quality material in a time efficient and cost effective manner. Performance evaluation of the fabricated films and their application for SPECT imaging are also discussed.

  3. 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...

  4. Sexualidade vivenciada na gestação: conhecendo essa realidade

    OpenAIRE

    Bartira Nunes Barbosa; Aparecida Neuritianny Chaves Gondim; Jamile Souza Pacheco; Hélcia Carla Santos Pitombeira; Linicarla Fabíole Gomes; Lydia Freitas Vieira; Ana Kelve de Castro Damasceno

    2011-01-01

    Este estudo objetivou caracterizar a sexualidade de gestantes. Estudo transversal, quantitativo e descritivo, realizado com 108 gestantes em um centro de saúde de Fortaleza-CE, de novembro/2008 a março/2009, utilizando-se formulário para coleta de dados. Foram obedecidas as normas éticas de pesquisa com seres humanos. Destaca-se que 43,5% das gestantes receberam informação sobre sexualidade no pré-natal, 86,1% relataram relações sexuais na gestação, 58,3% dos companheiros as procuravam na mes...

  5. Drogas na Escola: análise das vozes sociais em jogo

    OpenAIRE

    Barros, João Paulo Pereira; Colaço, Veriana de Fátima Rodrigues

    2015-01-01

    O artigo visa analisar vozes sociais em jogo na produção de sentidos sobre drogas entre adolescentes, em um grupo de discussão sobre saúde no contexto escolar. Ancorando-se na Saúde Coletiva e nos legados de Vigotski e Bakhtin sobre os processos de significação, são utilizados dados de uma pesquisa de mestrado operacionalizada por observações-participantes e pela formação de um grupo de discussão em uma escola pública de Fortaleza/CE. Os resultados apontam tensões entre vozes sociais nos posi...

  6. The role of charge transfer in the oxidation state change of Ce atoms in the TM13-CeO2(111) systems (TM = Pd, Ag, Pt, Au): a DFT + U investigation.

    Science.gov (United States)

    Tereshchuk, Polina; Freire, Rafael L H; Ungureanu, Crina G; Seminovski, Yohanna; Kiejna, Adam; Da Silva, Juarez L F

    2015-05-28

    Despite extensive studies of transition metal (TM) clusters supported on ceria (CeO2), fundamental issues such as the role of the TM atoms in the change in the oxidation state of Ce atoms are still not well understood. In this work, we report a theoretical investigation based on static and ab initio molecular dynamics density functional theory calculations of the interaction of 13-atom TM clusters (TM = Pd, Ag, Pt, Au) with the unreduced CeO2(111) surface represented by a large surface unit cell and employing Hubbard corrections for the strong on-site Coulomb correlation in the Ce f-electrons. We found that the TM13 clusters form pyramidal-like structures on CeO2(111) in the lowest energy configurations with the following stacking sequence, TM/TM4/TM8/CeO2(111), while TM13 adopts two-dimensional structures at high energy structures. TM13 induces a change in the oxidation state of few Ce atoms (3 of 16) located in the topmost Ce layer from Ce(IV) (itinerant Ce f-states) to Ce(III) (localized Ce f-states). There is a charge flow from the TM atoms to the CeO2(111) surface, which can be explained by the electronegativity difference between the TM (Pd, Ag, Pt, Au) and O atoms, however, the charge is not uniformly distributed on the topmost O layer due to the pressure induced by the TM13 clusters on the underlying O ions, which yields a decrease in the ionic charge of the O ions located below the cluster and an increase in the remaining O ions. Due to the charge flow mainly from the TM8-layer to the topmost O-layer, the charge cannot flow from the Ce(IV) atoms to the O atoms with the same magnitude as in the clean CeO2(111) surface. Consequently, the effective cationic charge decreases mainly for the Ce atoms that have a bond with the O atoms not located below the cluster, and hence, those Ce atoms change their oxidation state from IV to III. This increases the size of the Ce(III) compared with the Ce(IV) cations, which builds-in a strain within the topmost Ce layer, and

  7. Studies on Ca2+-Doped CeBr3 Scintillating Materials

    Energy Technology Data Exchange (ETDEWEB)

    Guss, P. [NSTec; Foster, M. E. [SNL; Wong, B. M. [SNL; Doty, F. P. [SNL; Shah, K. [RMD; Squillante, M. [RMD; Glodo, J. [RMD; Yuan, D. [NSTec

    2013-07-03

    Despite the outstanding scintillation performance characteristics of cerium tribromide (CeBr3) and cerium-activated lanthanum tribromide (LaBr3:Ce), their commercial availability and application is limited due to the difficulties of growing large, crack-free single crystals from these fragile materials. The objective of this investigation was to employ aliovalent doping to increase crystal strength while maintaining the optical properties of the crystal. One divalent dopant (Ca2+) was investigated 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 investigated using the density functional theory within 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.

  8. Ethylene Glycol Adsorption and Reaction over CeOX(111) Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    T Chen; D Mullins

    2011-12-31

    This study reports the interaction of ethylene glycol with well-ordered CeO{sub x}(111) thin film surfaces. Ethylene glycol initially adsorbs on fully oxidized CeO{sub 2}(111) and reduced CeO{sub 2-x}(111) through the formation of one C-O-Ce bond and then forms a second alkoxy bond after annealing. On fully oxidized CeO{sub 2}(111) both recombination of ethylene glycol and water desorption occur at low temperature leaving stable -OCH{sub 2}CH{sub 2}O- (ethylenedioxy) intermediates and oxygen vacancies on the surface. This ethylenedioxy intermediate goes through C-C bond scission to produce formate species which then react to produce CO and CO{sub 2}. The formation of water results in the reduction of the ceria. On a reduced CeO{sub 2-x}(111) surface the reaction selectivity shifts toward a dehydration process. The ethylenedioxy intermediate decomposes by breaking a C-O bond and converts into an enolate species. Similar to the reaction of acetaldehyde on reduced CeO{sub 2-x}(111), the enolate reacts to produce acetaldehyde, acetylene, and ethylene. The loss of O from ethylene glycol leads to a small amount of oxidation of the reduced ceria.

  9. Development of accident tolerant FeCrAl-ODS steels utilizing Ce-oxide particles dispersion

    Science.gov (United States)

    Shibata, Hiroki; Ukai, Shigeharu; Oono, Naoko H.; Sakamoto, Kan; Hirai, Mutsumi

    2018-04-01

    FeCrAl-ODS ferritic steels with Ce-oxide dispersion instead of Y-oxide were produced for the accident tolerant fuel cladding of the light water reactor. Excess oxygen (Ex.O) was added to improve the mechanical property. The tensile strength at Ex.O = 0 is around 200 MPa at 700 °C, mainly owing to dispersed Ce2O3 particles in less than 10 nm size. The formation of the fine Ce2O3 particles is dominated by a coherent interface with ferritic matrix. With increasing Ex.O, an increased of number density of coarser Ce-Al type oxide particles over 10 nm size is responsible for the improvement of the tensile strength. Change of the type of oxide particle, CeO2, Ce2O3, CeAlO3, Al2O3, in FeCrAl-ODS steel was thermodynamically analyzed as a parameter of Ex.O.

  10. Bio diesel synthesis from pongamia pinnata oil over modified CeO2 catalysts

    International Nuclear Information System (INIS)

    Venkatesh; Sathgatta Z, M. S.; Manjunatha, S.; Thammannigowda V, V.

    2014-01-01

    This study investigates the use of CeO 2 , ZrO 2 , Mg O and CeO 2 -ZrO 2 , CeO 2 -Mg O, CeO 2 -ZrO 2 -Mg O mixed oxides as solid base catalysts for the transesterification of Pongamia pinnata oil with methanol to produce bio diesel. SO 4 2- /CeO 2 and SO 4 2- /CeO 2 -ZrO 2 were also prepared and used as solid acid catalysts for esterification of Pongamia pinnata oil (P-oil) to reduce the % of free fatty acid (FFA) in P-oil. The oxide catalysts were prepared by an incipient wetness impregnation method and characterized by techniques such as NH 3 -Tpd for surface acidity, CO 2 -Tpd for surface basicity and powder X-ray diffraction for crystallinity. The effect of nature of the catalyst, methanol to P-oil molar ratio and reaction time in esterification as well as in transesterification was investigated. The catalytic materials were reactive d and reused for five reaction cycles and the results showed that the ceria based catalysts have reasonably good reusability both in esterification and transesterification reaction. The test results also revealed that the CeO 2 -ZrO 2 modified with Mg O could have potential for use in the large scale bio diesel production. (Author)

  11. Effects of Surfactants on the Performance of CeO2 Humidity Sensor

    Directory of Open Access Journals (Sweden)

    Chunjie Wang

    2014-01-01

    Full Text Available Nanosized CeO2 powders were synthesized via hydrothermal method with different types of surfactants (polyethylene glycol (PEG, cetyltrimethylammonium bromide (CTAB, and sodium dodecylbenzenesulfonate (SDBS. X-ray diffraction, Raman spectroscopy, and transmission electron microscopy were utilized to characterize the phase structures and morphologies of the products. The sample with CTAB as surfactant (CeO2-C has the largest specific surface area and the smallest particle size among these three samples. The humidity sensor fabricated by CeO2-C shows higher performance than those used CeO2-P and CeO2-S. The impedance of the CeO2-C sensor decreases by about five orders of magnitude with relative humidity (RH changing from 15.7 to 95%. The response and recovery time are 7 and 7 s, respectively. These results indicate that the performance of CeO2 humidity sensors can be improved effectively by the addition of cationic surfactant.

  12. Enhanced multiferroic properties in La and Ce co-doped BiFeO3 nanoparticles

    Science.gov (United States)

    Priyadharsini, P.; Pradeep, A.; Sathyamoorthy, B.; Chandrasekaran, G.

    2014-07-01

    Room temperature multiferroic properties of BiFeO3 (BFO), Bi0.9La0.1FeO3 ((La)BFO) and Bi0.9La0.075Ce0.025FeO3 ((La,Ce)BFO) nanoparticles have been reported in this paper. XRD (X-ray diffraction) analyses of the nanoparticles show a decrease in the lattice constants and cell volume with the substitution of La and Ce. It is evident from the SEM (scanning electron microscope) micrographs that the (La,Ce) co-doped sample possesses dense microstructure made of smaller particles. Raman study accounts for the weakening of the strong hybridization between Bi-O by the substitution of La and Ce ions. This is also accompanied by an increase in the remanent magnetization, dielectric constant, and ferroelectric polarization. BFO nanoparticles show exchange bias effect under an applied magnetic field while the (La)BFO and (La,Ce)BFO samples show no trace of such effect. Ac-conductivity of (La,Ce) co-doped sample is observed to be several orders lesser in magnitude than bulk BFO ceramics. These results are interpreted by means of the subtle change in the structure, suppression of the spin cycloid and reduction of oxygen vacancies in the doped samples.

  13. Effect of Ce ions on MOX codeposition in oxide-electrowinning reprocessing

    Science.gov (United States)

    Sato, F.; Fukushima, M.; Myochin, M.; Namba, T.; Kormilitsyn, M. V.; Ishunin, V. S.; Bychkov, A. V.; Inagaki, T.

    2005-02-01

    An experiment of MOX codeposition from U Pu Ce containing molten salt in oxide -electrowinning reprocessing was performed. Composition of O2/Cl2/Ar mixed gas, Ce concentration and U/Pu concentration in the salt were chosen as variable parameters. Ten tests were performed in this experiment. Current efficiency in each test was about 60 99%, and apparent dependence of the current efficiency on concentration of Ce in the salt was not seen in this experiment. Recovered MOX deposits contained about 5 19 wt% of Pu and 0.5 2 wt% of Ce. Concentration of Pu and Ce in the MOX deposit was influenced by O2/Cl2/Ar mixed gas composition and Ce concentration in the salt, respectively. Microphotographs of cross-section show that the MOX deposit was a complex of small columnar crystals. Some parts of the cross-section were analyzed by EPMA. These results indicated that a U rich region (concentration of U: about 80 wt%) exists in central part of the crystal and Pu rich regions (concentration of Pu: about 80 wt%) scatter on its surface and Ce is distributed rather uniformly.

  14. Design of high quality doped CeO2 solid electrolytes with nanohetero structure

    International Nuclear Information System (INIS)

    Mori, T.; Ou, D.R.; Ye, F.; Drennan, J.

    2006-01-01

    Doped cerium (CeO 2 ) compounds are fluorite related oxides which show oxide ionic conductivity higher than yttria-stabilized zirconia in oxidizing atmosphere. As a consequence of this, a considerable interest has been shown in application of these materials for low (400-650 o C) temperature operation of solid oxide fuel cells (SOFCs). In this paper, our experimental data about the influence of microstructure at the atomic level on electrochemical properties were reviewed in order to develop high quality doped CeO 2 electrolytes in fuel cell applications. Using this data in the present paper, our original idea for a design of nanodomain structure in doped CeO 2 electrolytes was suggested. The nanosized powders and dense sintered bodies of M doped CeO 2 (M:Sm,Gd,La,Y,Yb, and Dy) compounds were fabricated. Also nanostructural features in these specimens were introduced for conclusion of relationship between electrolytic properties and domain structure in doped CeO 2 . It is essential that the electrolytic properties in doped CeO 2 solid electrolytes reflect in changes of microstructure even down to the atomic scale. Accordingly, a combined approach of nanostructure fabrication, electrical measurement and structure characterization was required to develop superior quality doped CeO 2 electrolytes in the fuel cells. (author)

  15. Surface electrochemistry of CO2 reduction and CO oxidation on Sm-doped CeO(2-x): coupling between Ce(3+) and carbonate adsorbates.

    Science.gov (United States)

    Feng, Zhuoluo A; Machala, Michael L; Chueh, William C

    2015-05-14

    The efficient electro-reduction of CO2 to chemical fuels and the electro-oxidation of hydrocarbons for generating electricity are critical toward a carbon-neutral energy cycle. The simplest reactions involving carbon species in solid-oxide fuel cells and electrolyzer cells are CO oxidation and CO2 reduction, respectively. In catalyzing these reactions, doped ceria exhibits a mixed valence of Ce(3+) and Ce(4+), and has been employed as a highly active and coking-resistant electrode. Here we report an operando investigation of the surface reaction mechanism on a ceria-based electrochemical cell using ambient pressure X-ray photoelectron spectroscopy. We show that the reaction proceeds via a stable carbonate intermediate, the coverage of which is coupled to the surface Ce(3+) concentration. Under CO oxidation polarization, both the carbonate and surface Ce(3+) concentration decrease with overpotential. Under CO2 reduction polarization, on the other hand, the carbonate coverage saturates whereas the surface Ce(3+) concentration increases with overpotential. The evolution of these reaction intermediates was analyzed using a simplified two-electron reaction scheme. We propose that the strong adsorbate-adsorbate interaction explains the coverage-dependent reaction mechanism. These new insights into the surface electrochemistry of ceria shed light on the optimization strategies for better fuel cell electrocatalysts.

  16. Facile in-situ reduction: Crystal growth and magnetic studies of reduced vanadium (III/IV) silicates CaxLn1-xVSiO5 (Ln = Ce-Nd, Sm-Lu, Y)

    Science.gov (United States)

    Abeysinghe, Dileka; Smith, Mark D.; Morrison, Gregory; Yeon, Jeongho; zur Loye, Hans-Conrad

    2018-04-01

    A series of lanthanide containing mixed-valent vanadium (III/IV) silicates of the type CaxLn1-xVSiO5 (Ln = Ce-Nd, Sm-Lu, Y) was synthesized as high quality single crystals from a molten chloride eutectic flux, BaCl2/NaCl. Utilizing Ca metal as the reducing agent, an in-situ reduction of V5+ to V3+/4+ as well as of Ce4+ to Ce3+ was achieved. The structures of 14 reported isostructural compounds were determined by single crystal X-ray diffraction. They crystallize in the tilasite (CaMgAsO4F) structure type in the monoclinic space group C2/c. The extended structure contains 1D chains of VO6 octahedra that are connected to each other via SiO4 groups and (Ca/Ln)O7 polyhedra. The magnetic susceptibility and the field dependent magnetization data were measured for CaxLn1-xVSiO5 (Ln = Ce-Nd, Sm, Gd-Lu, Y), and support the existence of antiferromagnetic behavior at low temperatures.

  17. Enhanced catalytic properties of Pt-based electrode by doped Cu and Ce

    Science.gov (United States)

    Yue, Dehuai; Yang, Bin

    2017-08-01

    Novel PtCuCeO x composite membrane electrode materials were fabricated on the surface of graphite fibrous cloth by ion beam sputtering (IBS). The cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were used to analyze the influence of doped Cu and Ce on the membrane electrocatalysis performance in a tri-electrode system. The phase composition, surface structure, interfacial structure and catalytic performance of PtCuCeO x membrane were studied by x-ray diffraction (XRD) and high resolution transmission electron microscope (HR-TEM&STEM). The results indicate that surface particles of membrane electrode are made up of PtCu alloy grains and a few CeO x grains, and the interface structure of oxide metal is formed between them. The crystal plane spacing between PtCu alloy grain is reduced by about 1.11% after the corrosion, which helps increase the electron density on Pt atom. As a result, the catalysis capability of PtCu alloy is enhanced. When the content of Ce is less than or equal to 0.28 wt.%, CeO x exists in the form of amorphous. It is exciting to demonstrate that the existence of CeO x enhances the dispersion of PtCuCeO x catalyst particles. The experimental results reveal that the synthesized material possesses the best electrochemical activity surface area (ESA) and exchange current density (i 0). Compared to pure Pt catalyst, this PtCuCeO x catalyst contains much less Pt content (only 42% of Pt catalyst). However, the electrochemical performance is enhanced by 71.8% compared with pure Pt.

  18. A DFT study of phenol adsorption on a low doping Mn–Ce composite oxide model

    Energy Technology Data Exchange (ETDEWEB)

    D́Alessandro, Oriana [CINDECA – Fac. Cs. Ex. UNLP, CCT – CONICET, Calle 47 Nro. 257, (1900) La Plata (Argentina); Pintos, Delfina García [ITHES–UBA, Pabellón de Industrias, (1428) Buenos Aires (Argentina); Juan, Alfredo, E-mail: cajuan@uns.edu.ar [Departamento de Física & IFISUR – UNS, Avda. Alem 1253, (8000) Bahía Blanca (Argentina); Irigoyen, Beatriz [ITHES–UBA, Pabellón de Industrias, (1428) Buenos Aires (Argentina); Sambeth, Jorge [CINDECA – Fac. Cs. Ex. UNLP, CCT – CONICET, Calle 47 Nro. 257, (1900) La Plata (Argentina)

    2015-12-30

    Graphical abstract: - Highlights: • Phenol is adsorbed on the structural-oxygen-deficient Ce-Mn-O(1 1 1) surface interacting with the Ce cation first neighbor to Mn dopant. • The O–H of the phenol group bond is stretched up to 1.69 Å. • Phenol interaction with the hydroxylated H–OH/Ce{sub 0.875}Mn{sub 0.125}O{sub 1.9375}(1 1 1) surface is 0.51 eV stronger than on the clean surface. • The C{sub 6}H{sub 5}–O fraction is adsorbed in a bridge position between Mn and Ce cations with a tilt angle of 69.62° in agreement with IR data. - Abstract: Density functional theory calculations (DFT + U) were performed on a low doping Mn–Ce composite oxide prepared from experimental data, including X-ray diffraction (XRD) and temperature-programmed reduction (TPR). We considered a 12.5% Mn-doped CeO{sub 2} solid solution with fluorite-type structure, where Mn replaces Ce{sup 4+} leading to an oxygen-deficient bulk structure. Then, we modeled the adsorption of phenol on the bare Ce{sub 0.875}Mn{sub 0.125}O{sub 1.9375}(1 1 1) surface. We also studied the effect of water adsorption and dissociation on phenol adsorption on this surface, and compared the predictions of DFT + U calculations with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements. The experimental results allowed us to both build a realistic model of the low doping Mn–Ce composite oxide and support the prediction that phenol is adsorbed as a phenoxy group with a tilt angle of about 70° with respect to the surface.

  19. Study of the defect structure of ''pure'' and doped nonstoichiometric CeO2

    International Nuclear Information System (INIS)

    Blumenthal, R.N.

    1975-09-01

    Electrical conductivity and thermogravimetric measurements were made on Ta 2 O 5 -doped nonstoichiometric CeO 2 (i.e. Ce/sub 1-y/Ta/sub y/O/sub 2-x/ ) as a function of temperature and oxygen partial pressure. Over a limited range of temperature and nonstoichiometry, the isothermal dependence of the electrical conductivity on nonstoichiometry may be described by the equation sigma = A + Bx, where A is the electronic conductivity associated with the electronic defects produced by doping CeO 2 with Ta 2 O 5 . The electronic conductivity resulting from the nonstoichiometric defect reaction O/sup x/ + 2Ce/sub Ce//sup x/ = V 0 + 2Ce'sub Ce/ + 1 / 2 O 2 (g) is equal to Bx. The ionic conductivity may be described by the relation sigma/sub i/ = B[y+x]eμ'/sub V 0 / exp (--E/sub i//kT), and the electronic conductivity by the isothermal expressions sigma/sub e/ proportional to P/sub O 2 //sup -1/4/ and sigma/sub e/ proportional to x; x less than 3 x 10 -2 . These results are consistent with defect models involving doubly ionized oxygen vacancies. An empirical expression (i.e. Δ anti H/sub O 2 / proportional to y/2 or z/4) was obtained relating the dependence of Δ anti H/sub O 2 / on the dopant concentration of lower valent foreign cations (e.g. y/2 for Ce/sub 1-y/M/sub y/O/sub 2-y-x/ and z/4 for Ce/sub 1-z/M/sub z/O/sub 2-z/2-x/ where M = Ca, Sr and M' = Y, La). (auth)

  20. Transport, thermal, and magnetic properties in heavy-fermion superconductor Ce2CoIn8

    International Nuclear Information System (INIS)

    Yamashita, Tetsuro; Ohara, Shigeo; Sakamoto, Isao

    2011-01-01

    We have grown high purity single crystals of Ce 2 CoIn 8 . We investigated its transport, thermal, and magnetic properties. Ce 2 CoIn 8 has a superconducting ground state with a distinct non-Fermi liquid character. We propose one of the CEF level schemes of Ce 2 CoIn 8 . We have grown high purity single crystals of Ce 2 CoIn 8 using the self-flux technique, and have investigated its transport, thermal, and magnetic properties, including the anisotropic features. Single crystals of Ce 2 CoIn 8 were grown in the lower temperature region to avoid the formation of un-wanted phases such as CeCoIn 5 and CeIn 3 impurities. The results of the structural and physical measurements imply that the present single crystals have high purity. The electrical resistivity and specific heat measurements demonstrate that Ce 2 CoIn 8 has a superconducting ground state with a distinct non-Fermi liquid character. This indicates that the superconductivity in Ce 2 CoIn 8 arises out of the verge of the underlying quantum critical instability mediated by the antiferromagnetic correlations. Additionally, we investigate the crystalline electric field (CEF) energy scheme based on the temperature dependence of the specific heat and the anisotropic features in the susceptibility. We propose one of the CEF level schemes calculated on the basis of the CEF model that the first and second CEF states are located at Δ 1 = 82 K and Δ 2 = 102 K above the ground state doublet, respectively.

  1. Environmentální aspekty provozu vozů na CNG

    OpenAIRE

    Raiskup, Martin

    2016-01-01

    Tato bakalářská práce je zaměřená na téma environmentální aspekty provozu vozů na CNG. Nejprve je představen zemní plyn jako palivo pro spalovací motory. Jsou zhodnoceny jeho výhody a nevýhody. Dále jsou popsány jednotlivé spalovací systémy a komponenty motoru na stlačený zemní plyn. Hlavní část práce je zaměřená na ekologii. Je popsán vliv na životní prostředí u spalování stlačeného zemního plynu v porovnání s konvenčními palivy. Toto porovnání je provedeno také podle objektivnější Well to W...

  2. Inovace politik ke kombinaci práce a rodiny na úrovni státu a korporací

    Czech Academy of Sciences Publication Activity Database

    Formánková, Lenka

    2009-01-01

    Roč. 10, č. 1 (2009), s. 63-67 ISSN 1213-0028. [Policy Innovations at National and Company Level that promote Work Family Balance . Lublan, 13.02.2009] R&D Projects: GA ČR GA403/09/1839 Institutional research plan: CEZ:AV0Z70280505 Keywords : Slovenia * work - life balance * gender equality Subject RIV: AO - Sociology, Demography

  3. Rodiče na trhu práce: mezi prací a péčí

    Czech Academy of Sciences Publication Activity Database

    Křížková, Alena; Vohlídalová, Marta

    2009-01-01

    Roč. 45, č. 1 (2009), s. 31-60 ISSN 0038-0288 R&D Projects: GA AV ČR IAA700280804; GA ČR GA403/05/2474; GA MPS 1J034/05-DP2 Institutional research plan: CEZ:AV0Z70280505 Keywords : gender and labor market * gender equality * work / life balance Subject RIV: AO - Sociology, Demography Impact factor: 0.562, year: 2009

  4. Diskriminace na trhu práce, generové mzdové rozdíly

    OpenAIRE

    Bílíková, Petra

    2011-01-01

    The bachelor thesis deals with discrimination in the labour market, focusing on gender pay gap. The theretical part describes gender differences from the sociological perspective, problems of coordination of privat life and work and gender integration in the companies. The aim of practical part is analysis of actual situation in the labour market in term of gender. In conclusion are placed results of questionnaire survey, which analyses experiences of interviewed people in discrimination.

  5. Diskriminace na trhu práce, generové mzdové rozdíly

    OpenAIRE

    Plívová, Pavla

    2010-01-01

    This thesis deals with discrimination in the labor market, focusing on gender wage differentials. Interprets the various models explaining discrimination in the labor market. Among these models include a model with discriminatory preferences, discriminating monopsony, the theory of statistical discrimination and displacement model with a different attitude to the profession. Explains the causes of wage differences between men and women. Further examines the legislation at national and interna...

  6. Diskriminace na trhu práce, genderové mzdové rozdíly

    OpenAIRE

    Pospíšilová, Kateřina

    2010-01-01

    This thesis deals with discrimination in the labour market with a focus on gender wage differentials. It explains the differences between men and women from the sociological perspective, causes of different wages, the effect of compensating differences and investment in human capital. It presents discriminatory models: the model with discriminatory preferences, the discriminatory monopsony model, the model of statistical discrimination and the displacement model of discrimination. The practic...

  7. POSTAVENÍ PROPUŠTĚNÝCH VĚZŇŮ NA TRHU PRÁCE V ČESKÉ REPUBLICE

    OpenAIRE

    Pešatová, Martina

    2012-01-01

    The main goal of this thesis is to analyze the effectiveness of activities helping people released from an execution of punishment with integrating into the Czech labour market. Attention is drawn to the research question whether the monitored activities reduce reconviction of persons released from a prison and whether they increase their employability. The thesis concludes by identifying main problems of employing the target group and offers recommendation for their solution. The hypothesis ...

  8. A molecular dynamics study for the extraction of Cs+ and Na+ ions using dicyclohexano-18-crown-6 with octanol

    International Nuclear Information System (INIS)

    Biswas, Rima; Ghosh, Pallab; Banerjee, Tamal; Ali, Sk. Musharaf

    2016-01-01

    In this work we report a molecular dynamics study of the interfacial behavior involved in the cesium and sodium ion extraction by dicyclohexano-18-crown-6 (DCH18C6). Thereafter to understand the mechanism of complexation and the behavior of crown ether ligand, crown ether (CE) molecules, Cs + NO 3 - and Na + NO 3 - ions were inserted randomly in the Octanol-water biphasic system. In case of Na + NO 3 and Cs + NO 3 mixed system, it was observed that Cs + ion was extracted from water phase to octanol phase. The Na + ion was found to prefer to remain at the interface without complexation with DCH18C6. For the individual systems consisting of only Na + NO 3 , the complexed moiety (Na + -CE) formed during the simulation was found to diffuse slowly as compared to other free species. The binding energies during complexation of Na + cations with crown ether (DCH18C6) were further computed. The RDF peak height of 80 suggesting a high stability and a strong interaction for the complexed species is shown. The large magnitude of the RDF peak between sodium and oxygen is similar to that obtained by Pooja et al. and Maerzke et.al. The non bonded interaction energies during complexation of Na + cation with DCH18C6 were also analyzed. (author)

  9. The effects of binding type on luminescence LED phosphor based on GGG/Ce3+

    Science.gov (United States)

    Mikhailov, M. M.; Neshchimenko, V. V.; Shavlyuk, V. V.

    2014-12-01

    Luminescence and reflectance spectra of coatings based on gadolinium gallium garnet doped by cerium (GGG/Ce3+) with silicone resin or potassium liquid glass compound were analyzed depending on concentration. It was established that the maximum emissions of the coatings at 75 wt.% compound concentration have luminescence band at 570 nm and absorption band at 470 nm. Both bands were detected by absorption or emission of cerium ions in gadolinium gallium garnet. Ce3+ ion transition into Ce4+ ion was observed upon quantum absorption, and the reverse transition was observed upon quantum emission.

  10. CeO2 based catalysts for the treatment of propylene in motorcycle's exhaust gases

    OpenAIRE

    Pham, Phuong Thi Mai; Minh, Thang Le; Nguyen, Tien The; Van Driessche, Isabel

    2014-01-01

    In this work, the catalytic activities of several single metallic oxides were studied for the treatment of propylene, a component in motorcycles? exhaust gases, under oxygen deficient conditions. Amongst them, CeO2 is one of the materials that exhibit the highest activity for the oxidation of C3H6. Therefore, several mixtures of CeO2 with other oxides (SnO2, ZrO2, Co3O4) were tested to investigate the changes in catalytic activity (both propylene conversion and CO2 selectivity). Ce0.9Zr0.1O2,...

  11. Mechanical properties of Ce-TZP ceramics obtained from powders prepared by lyophilization of coprecipitated

    International Nuclear Information System (INIS)

    Andrade Nono, M.C. de

    1992-01-01

    In this paper is shown and discussed the influence of freeze-drying process on the physical characteristics of powder as well as on the microstructural, characteristics, on tetragonal-to-monoclinic stress induced transformation and, finally, on some mechanical properties of the Ce-TZP ceramics (bending strength, Vickers hardness and fracture toughness). Powders containing different Ce O 2 content were prepared by freeze-drying process and conventional drying of Ce and Zr coprecipitated hydroxides from initial chlorides. The powder characteristics show adequate compaction and sintering behavior. (author)

  12. Room-temperature synthesis and photoluminescence of hexagonal CePO4 nanorods

    Science.gov (United States)

    Zhu, J.; Zhang, K.; Zhao, H. Y.

    2018-01-01

    Hexagonal CePO4 nanorods were synthesized via a simple chemical precipitation route at room-temperature without the presence of surfactants and then characterized by powder X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectrometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible (UV–vis) absorption and photoluminescence (PL) spectroscopy. Hexagonal CePO4 nanorods exhibit strong ultraviolet absorption and ultraviolet luminescence, which correspond to the electronic transitions between 4f and 5d state of Ce3+ ions.

  13. Thermodynamical study of boron doped CeX{sub 3} (X=Pd, Rh)

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Ramesh [Dept. of Physics, Mewar University, Chittorgarh Rajasthan-India (India); Dwivedi, Shalini; Sharma, Yamini, E-mail: sharma.yamini62@gmail.com [Theoretical Condensed Matter Physics Laboratory, Dept. of Physics, Feroze Gandhi College, Raebareli-229001 U.P (India)

    2016-05-06

    The structural, electronic, thermal, and optical properties of cubic non magnetic CeX{sub 3}(X=Pd, Rh) compounds which crystallize in the Au{sub 3}Cu structure have been studied using the projected augmented wave (PAW) method within the density functional theory (DFT) with generalized gradient approximation (GGA) for exchange correlation potential. In this paper we have calculated the band structure which are interpreted using the density of states. The optical properties such as extinction coefficients clearly illustrate the changes in CeX{sub 3} due to intercalation of boron. Lattice instability is observed in CePd{sub 3}B from the calculated dynamical properties.

  14. Ab initio investigation of the noncollinear magnetic structure of CeFeAsO

    Science.gov (United States)

    Liu, Juan; Luo, Bo; Sun, Zhaoyu; Fu, Huahua; Yao, Kailun

    2011-09-01

    The noncollinear magnetic ground state in CeFeAsO has been investigated using the density-functional theory. When the spin-orbit coupling is discarded, the magnitude of the Ce-magnetic moment (0.87μB) is independent of the spin direction and is in accordance with the experimental value of 0.83(2)μB. However, when the spin-orbit coupling is considered, the Ce-orbital moments change with the internal magnetic field and affect the total magnetic moment of Ce. One type of Ce ions has a magnetic moment of 0.909μB, which is very close to the experimental value. The other type of Ce ions has a magnetic moment of 0.488μB, which has not been previously reported. The magnetic moments of the rare-earth metals in NdFeAsO and PrFeAsO are also twice those of experimental observations. The difference between the rare earth magnetic-moment errors of the three compounds imply that magnetism is related to the onset of the superconducting critical temperature. At the same time, the calculated Fe-magnetic moments in all solutions are over 2.0μB. From the band structure and density of states (DOS), the Ce 4f and Fe 3d orbits are shown to have major contributions to the Fermi level. Four bands in CeFeAsO cross the Fermi level at the Γ (0, 0, 0) point and form four hole-like pockets. The superexchange interaction between the Ce 4f and Fe 3d electrons via oxygen ions is discussed. Furthermore the results show that the Fermi surface shape varies with the Ce spin direction, revealing that electroconductibility is directly affected by the Ce-spin direction. If the Ce spin is perpendicular to the FeAs plane, the electronic field gradient (EFG) changes from a negative value into a positive value.

  15. RESPONSE OF SOIL MICROBIAL BIOMASS TO CeO2 NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    Livia Vittori Antisari

    2011-12-01

    Full Text Available Aim of this work was to assess the impact of the chronic exposure of CeO2 nanoparticles (NPs (50 to 105 nm nominal size on soil microbial biomass.To evaluate if the CeO2 NPs can affect the soil quality, they were mixed to an A1 and A2 horizon of Epileptic Cambisols at a concentrations of 100 ppm and incubated in lab for short and medium (7 and 60 days times, at a constant temperature (25°C and moisture (60% WHC.The preliminary results of the soil physicochemical analyses have showed an insolubility of the CeO2 NPs at short-term incubation in water, EDTA and aqua regia. The biological assays detect a storing of Ce-CeO2 in the microbial biomass at short time that decreases in the C amount. An increment of the basal respiration and a decrease in the amount of carbon soil microbial biomass determined a higher metabolic quotient (qCO2 than the control test, that identifies a stressful situation, most evident in the short term condition.Physical-chemical characterization of the CeO2 NPs and of the soil before and after the NPs addition, was carried out by means of Environmental Scanning Electron Microscope (ESEM and an Energy Dispersive Spectroscopy (EDS. The investigations showed Ce-NPs and Ce-compounds in both- incubation-condition samples. The control soil showed the presence of cerium associated with other elements, like P, Nd, La, Th e Si. From literature, it appears that these elements identify Monazite-Ce/Nd minerals, whose chemical formulas are respectively (Ce, La, Nd, Th PO4 and (Nd, Ce, La (P, Si O4. The presence of CeO2 NPs was clearly detected in soil and recognized by ESEM morphological observations coupled with EDS characterization. The NPs chemical composition appears unaltered, while the size can be modified by NPs aggregation and clustering.The results contribute to setting reference baseline values of cerium in soil and indicate an impact on the amount of carbon soil microbial biomass due to a higher metabolic quotient (qCO2 that

  16. Data and analyses of phase relations in the Ce-Fe-Sb ternary system.

    Science.gov (United States)

    Zhu, Daiman; Xu, Chengliang; Li, Changrong; Guo, Cuiping; Zheng, Raowen; Du, Zhenmin; Li, Junqin

    2018-02-01

    These data and analyses support the research article "Experimental study on phase relations in the Ce-Fe-Sb ternary system" Zhu et al. (2017) [1]. The data and analyses presented here include the experimental results of XRD, SEM and EPMA for the determination of the whole liquidus projection and the isothermal section at 823 K in the Ce-Fe-Sb system. All the results enable the understanding of the constituent phases and the solidification processes of the as-cast alloys as well as the phase relations and the equilibrium regions at 823 K in the Ce-Fe-Sb ternary system over the entire composition.

  17. The exceptional behaviour of Pr, Ce and Tb in high-Tc superconductors

    International Nuclear Information System (INIS)

    Staub, U.

    1999-01-01

    X-ray absorption and diffraction, elastic and inelastic neutron scattering and magnetization measurements are used to study the electronic, structural and magnetic properties of two series of high-T c superconductors containing Ce, Tb and Pr. These results are interpreted with regard to the well known valence instabilities often shown by these rare earth ions. Ce is found to be non-magnetic, in contrast to Tb, which exhibits complex 2D magnetic properties. Although the measurements provide detailed understanding of the behaviour of Ce and Tb, there is still no consensus why Pr suppresses superconductivity in particular cuprates. (orig.)

  18. Magnetic properties of the layered oxypnictides (LnOMnAs (Ln = La, Ce, Pr, Nd

    Directory of Open Access Journals (Sweden)

    Morosawa Y.

    2014-07-01

    Full Text Available We have investigated the rare earth elements dependence on the magnetism to understand the contribution to physical properties of the 4f electrons of (LnOMnAs (Pn = La, Ce, Pr, Nd. (CeOMnAs, (PrOMnAs and (NdOMnAs shows the antiferromagnetic behaviors at low temperature. (CeOMnAs and (NdOMnAs have the magnetic anomalies around 34 K and 24 K, respectively. So, it is speculated that the anomalies depend on the Mn -Mn distance directly

  19. Tumour targeting with monovalent fragments of anti-neuroblastoma antibody chCE7

    International Nuclear Information System (INIS)

    Carrel, F.; Novak-Hofer, I.; Ruch, C.; Zimmermann, K.; Amstutz, H.

    1997-01-01

    The in vitro and in vivo behaviour of the monovalent single chain (scFv) and Fab-fragments derived from anti-neuroblastoma antibody chCE7 is reported. When comparing tumour uptake and -retention of radioactivity of 67 Cu-labelled monovalent chCE7 with divalent chCE7 F(ab') 2 the advantage of the radiocopper label over the radioiodine label was more pronounced with the divalent (internalising) F(ab') 2 fragments. (author) 1 fig., 1 ref

  20. Positivity-preserving space-time CE/SE scheme for high speed flows

    KAUST Repository

    Shen, Hua

    2017-03-02

    We develop a space-time conservation element and solution element (CE/SE) scheme using a simple slope limiter to preserve the positivity of the density and pressure in computations of inviscid and viscous high-speed flows. In general, the limiter works with all existing CE/SE schemes. Here, we test the limiter on a central Courant number insensitive (CNI) CE/SE scheme implemented on hybrid unstructured meshes. Numerical examples show that the proposed limiter preserves the positivity of the density and pressure without disrupting the conservation law; it also improves robustness without losing accuracy in solving high-speed flows.