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Sample records for ba ce sm

  1. Novel RZn2Ga2 (R = La, Ce, Pr, Nd, Sm) intermetallic compounds with BaAl4-type structure

    International Nuclear Information System (INIS)

    Research highlights: → Intermetallic RZn2Ga2 (R = La, Ce, Pr, Nd, Sm) compounds crystallize in tetragonal BaAl4-type structure. → Unit cell volume of all gallides gradually decreases along the R series, just in agreement with the so-called lanthanide contraction mechanism. → The Pr-, Nd- and Sm-based compounds order antiferromagnetically at low temperatures with likely contribution of some ferromagnetic components. - Abstract: Novel RZn2Ga2 intermetallics with R = La, Ce, Pr, Nd, Sm have been synthesized and characterized with regards to their crystal structures and magnetic properties. The compounds form with a tetragonal structure of the BaAl4 type (space group I4/mmm). Except for LaZn2Ga2, they exhibit localised magnetism due to the presence of magnetic moments on the respective trivalent rare earth ions. The Pr-, Nd- and Sm-based compounds order antiferromagnetically at low temperatures with likely contribution of some ferromagnetic components.

  2. Investigation of GdBaCo2-xFexO6-δ (x = 0, 0.2) - Ce0.8Sm0.2O2 composite cathodes for intermediate temperature solid oxide fuel cells

    Science.gov (United States)

    Tsvetkova, N. S.; Zuev, A. Yu.; Tsvetkov, D. S.

    2013-12-01

    The double perovskites GdBaCo2-xFexO6-δ (x = 0, 0.2) and composites (100 - y) GdBaCo2-xFexO6-δ (x = 0, 0.2) - y Ce0.8Sm0.2O2 (y = 10-50 wt.%) were investigated as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). Chemical compatibility of GdBaCo2-xFexO6-δ (x = 0, 0.2) with solid electrolyte Ce0.8Sm0.2O2, thermal expansion, DC conductivity and electrochemical performance of (100 - y) GdBaCo2-xFexO6-δ (x = 0, 0.2) - y Ce0.8Sm0.2O2 (y = 10-50 wt.%) were studied. Partial substitution of Fe for Co was shown to lead to decrease of double perovskite GdBaCo2-xFexO6-δ reactivity with the solid electrolyte Ce0.8Sm0.2O2. Polarization resistance of cathodes studied was found to depend significantly on firing temperature. Variation of solid electrolyte content in (100 - y) GdBaCo2-xFexO6-δ (x = 0, 0.2) - y Ce0.8Sm0.2O2 (y = 10-50 wt.%) composites was shown to allow to optimize their electrochemical performance. Cathode materials of 80 wt.% GdBaCo2O6-δ - 20 wt.% Ce0.8Sm0.2O2 and 65 wt.% GdBaCo1.8Fe0.2O6-δ - 35 wt.% Ce0.8Sm0.2O2 were found to have the lowest polarization resistances and reasonable values of thermal expansion coefficient (TEC) and, therefore, can be considered as promising cathode materials for IT-SOFCs.

  3. Textured BaCe0.5Zr0.3Ln0.2O3−δ (Ln = Yb, Y, Gd, Sm, Nd and La) ceramics obtained by the aid of solid-state reactive sintering method

    International Nuclear Information System (INIS)

    Dense BaCe0.5Zr0.3Ln0.2O3−δ (Ln = Yb, Y, Gd, Sm, Nd and La) proton-conducting ceramic materials are successfully prepared by solid-state reactive sintering method. The XRD analysis shows that the surface of ceramics is characterized by a pronounced texturing, whereas the volume of the same samples (obtained by grinding of ceramics) reveals the typical patterns. The degree of surface texture for BaCe0.5Zr0.3Ln0.2O3−δ (Ln = Yb, Y, Gd, Sm and Nd) samples is ranged between 24% and 39%, whereas for the BaCe0.5Zr0.3La0.2O3−δ ceramic it reaches 99%. The possible reason of particular texture of ceramics is proposed

  4. Preparation and electrochemical performances of LaBaCo2O5 +δ-Ce0.8Sm0.2O1.9 graded composite cathode%梯度复合阴极LaBaCo2O5+δ-Ce0.8Sm0.2O1.9的制备及电化学性能

    Institute of Scientific and Technical Information of China (English)

    李瑞锋; 陈涵; 郭露村

    2012-01-01

    采用机械混合法制备中温固体氧化物燃料电池梯度复合阴极材料LaBaCo2O5+δ-Ce0.8Sm0.2O1.9(LBCO - SDC).通过X线衍射(XRD)分析、扫描电镜(SEM)分析、热膨胀法、交流阻抗谱法和循环伏安法分别对晶体结构、界面微观结构、热膨胀性及电化学性能进行表征.结果表明:LBCO阴极与SDC电解质之间具有良好的化学相容性;电解质SDC的添加有效地降低了阴极材料LBCO的热膨胀系数;双层梯度复合阴极比单层阴极表现出更小的比表面电阻以及极化过电位,显示出更好的电化学性能;在700℃时,双层梯度复合阴极的比表面电阻与LBCO阴极相比下降了约13.2%,极化过电位(电流密度为0.20 A/cm2)从51.0 mV下降到46.4 mV.%The LaBaCo205+δ-Ce0.8Sm0201. 9(LBC0-SDC) graded composite cathode for intermediate temperature solid oxide fuel cells was prepared by a mechanical mixing method. The crystal structure, interfacial microstructure,thermal expansion, and electrochemical performances were investigated by X-ray diffraction (XRD) ,scanning electron microscopy(SEM) ,dilatometry, AC impedance, and cyclic voltamme-try techniques. Results showed that the LBCO cathode had good chemical compatibility with the SDC electrolyte. The addition of SDC electrolyte to LBCO cathode could effectively reduce its thermal expansion coefficient. The double-layer graded composite cathode exhibited smaller area-specific resistance and polarization overpotential than the monolayer cathode, thus showing the better electrochemical performance. For graded composite cathode,the area-specific resistance value was about 13. 2% lower than that of LBCO at 700 t ,and the cathodic overpotential was decreased from 51.0 mV to 46. 4 mV at a current density of0. 20 A/cm2.

  5. THERMAL EXPANSION BEHAVIOR OF THE Ba0.2Sr0.8Co0.8Fe0.2O3−δ (BSCF WITH Sm0.2Ce0.8O1.9

    Directory of Open Access Journals (Sweden)

    M. AHMADREZAEI

    2014-03-01

    Full Text Available Nanostructured perovskite oxides of Ba0.2Sr0.8Co0.8Fe0.2O3−δ (BSCF were synthesized through the co-precipitation method. The thermal decomposition, phase formation and thermal expansion behavior of BSCF were characterized by thermogravimetric analysis, X-ray diffraction (XRD, and dilatometry, respectively. XRD peaks were indexed to a cubic perovskite structure with a Pm3m (221 space group. All the combined oxides produced the desired perovskite-phase BSCF. The microstructures were characterized by scanning electron microscopy (SEM and transmission electron microscopy (TEM. The TEM analysis showed that BSCF powders had uniform nanoparticle sizes and high homogeneity. The cross-sectional SEM micrograph of BSCF exhibited a continuous and no delaminated layer from the electrolyte-supported cell. The thermal expansion coefficient (TEC of BSCF was 16.2×10-6 K-1 at a temperature range of 600°C to 800°C. Additional experiments showed that the TEC of BSCF is comparable to that of Sm0.2Ce0.8O1.9 (SDC within the same temperature range. The results demonstrate that BSFC is a promising cathode material for intermediate-temperature solid-oxide fuel cells.

  6. Synthesis and characterization of BaCeO3 nanocrystals viasolvothermal-based method

    Institute of Scientific and Technical Information of China (English)

    XU Chao; ZHU Junwu; YANG Xujie; LU Lude; WANG Xin

    2008-01-01

    A facile approach to preparing well-dispersed nanocrystals of BaCeO3 was developed by a combination of solvothermal and annealing processes. The precursor consisted of amorphous BaCO3 and CeO2, and the conversion of the precursor to crystalline BaCeO3 nanocrystals occurred upon heat treatment at a relatively low temperature. The as-processed BaCeO3 had an orthorhombic structure and the average size of such crystals was approximately 80 nm. The obtained products were characterized by Fourier Transform Infrared (FT-IR), X-Ray Diffraction (XRD), Laser Raman Spectroscopy (LRS), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectrometry (EDS), and Transmission Electron Microscopy (TEM). This preparation process could also be used to synthesize doped barium cerate complex oxides BaCe0.95M0.05O3-d (M=Y, Nd, Gd, and Sm).

  7. 中温固体氧化物燃料电池SmBaCo_2O_(5+δ)–Sm_(0.2)Ce_(0.8)O_(1.9)复合阴极材料的电化学性能%Electrochemical Performance of SmBaCo2O5+δ-Sm0.2Ce0.8O1.9 Composite-Cathode for Intermediate Temperature Solid Oxide Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    王小连; 丁岩芝; 林彬; 卢肖永; 陈永红

    2012-01-01

    The cathode powder of double perovskites-type SmBaCo 2 O 5+δ(SBCO) and electrolyte powder of fluorite-structure Sm 0.2 Ce 0.8 O 1.9(SDC) were synthesized by a citric acid-nitrates self-propagating combustion method.The composite-cathode was obtained by mixing and grinding the SBCO and SDC powders at a mass ratio of 3:2.The chemical compatibility,electrical conductivity and thermal expansion coefficient(TEC) of the composite-cathode(SBCO-SDC) were characterized by X-ray diffraction,direct current four-terminal method and thermal dilatometry,respectively.An anode-supporting fuel cell of Ni-SDC|SDC|SBCO-SDC was fabricated and the performance of the cell was analyzed.The cross-section microstructure and polarization of the cell were investigated using a scanning electron microscope(SEM) and AC impedance spectroscopy.The results indicate that there are no interactions between SBCO and SDC at 1 000 ℃.The electrical conductivity of the SBCO-SDC composite-cathode reached to 369–234 S/cm at 450–800 ℃.The addition of SDC decreased the TEC of the composite-cathode.The single cell has an ideal microstructure and a good interface among anode,electrolyte and cathode.The polarization resistance of the electrodes was 0.031.cm 2 at 650 ℃.The cell with an open-circuit potential of 0.77 V and a maximum output power density of 640 mW/cm 2 was obtained when the humidified(about 3% H 2 O) hydrogen as a fuel and air as oxidant were used at 650 ℃.It was demonstrated that the SBCO-SDC composite-cathode could be used as a potential candidate cathode for intermediate temperature solid oxide fuel cell.%采用柠檬酸–硝酸盐自蔓延燃烧法分别合成了双钙钛矿结构的SmBaCo2O5+δ(SBCO)阴极粉体和萤石型Sm0.2Ce0.8O1.9(SDC)电解质粉体,按3:2的质量比混合上述粉体研磨后得到复合阴极。利用X射线衍射仪研究化学相容性,直流四端子法测量电导率,热膨胀仪测量热膨胀系数;构建阳极支撑型单电池(Ni

  8. White light generation in Ce3+-Tb3+-Sm3+ codoped oxyfluoroborate glasses

    International Nuclear Information System (INIS)

    Ce3+, Tb3+and Sm3+ oxyfluoroborate glasses were prepared and characterized using absorption, photoluminescence and time decay spectral analysis respectively. The decrease of emission peak intensity and lifetime values of Ce3+ ions are observed by introducing Tb3+ and Sm3+ into glass. This is due to an efficient energy transfer from Ce3+ to Tb3+, Sm3+; Tb3+ to Sm3+ and cross-relaxation channels. Further, the important characteristic parameters of white light emitting materials viz., energy transfer efficiency, chromaticity color coordinates, correlated color temperature and color purity are evaluated. - Highlights: • The energy transfer from Ce3+ to Tb3+; Sm3+ and Tb3+ to Sm3+ is studied. • CIE color coordinates fall in blue, green and white regions. • Ce3+-Tb3+-Sm3+ doped glasses exhibit white light emission under 312 nm excitation

  9. Crystal structure of the RGa2Ni compounds (R=Ce, La, Pr, Nd, Sm, Gd)

    International Nuclear Information System (INIS)

    RGa2Ni compounds were synthesized by direct reaction between metals in the electric-arc furnace in argon atmosphere. Purity of the initial components was as follows: REM >=99.86, Ga - 99.99, Ni - 99.99 %. Homogenizing annealing was exercised at 600 deg C during 160 to 200 hours. The structure of NdGa2Ni compound was investigated by the powder method. The divergence factor for non-zero reflexes of the diffractogram (DRON-2, O, FeK2) makes up 0.131. NdGa2Ni is a new structural type. The structure is considered to be a hybrid one comprising fragments of BaAl4-and AlB2 structural types. Compounds isostructural to NdGa2Ni are detected in the La-, Ce-, Pr-, Sm-, Gd systems

  10. Cobalt-free Composite Ba0.5Sr0.5Fe0.9Ni0.1O3-δ-Ce0.8Sm0.2O2-δ as Cathode for Intermediate-Temperature Solid Oxide Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    Xiangfeng Chu; Feng Liu; Weichang Zhu; Yongping Dong; Mingfu Ye; Wenqi Sun

    2012-01-01

    New cobalt-free composites consisting of Ba0.5Sr0.5Fe0.9Ni0.1O3-δ (BSFN) and Ce0.8Sm0.2O2-δ (SDC) were investigated as possible cathode materials for intermediate-temperature solid oxide fuel cell (IT-SOFC). BSFN, which was synthesized by auto ignition process, was chemically compatible with SDC up to 1100 ℃ as indicated by X-ray diffraction analysis. The electrical conductivity of BSFN reached the maximum value of 57 S.cm-1 at 450 ℃. The thermal expansion coefficient (TEC) value of BSFN was 30.9×10-6 K-1, much higher than that of typical electrolytes. The electrochemical behavior of the composites was analyzed via electrochemical impedance spectroscopy with symmetrical cells BSFN-SDC/SDC/BSFN-SDC. The area specific interracial polarization resistance (ASR) decreased with increasing SDC content of the composite. The area specific interracial polarization resistance (ASR) at 700 ℃ is only 0.49, 0.34 and 0.31 Ω.cm2 when 30, 40, and 50 wt% SDC was cooperated to BSFN, respectively. These results suggest that BSFN-SDC is a possible candidate for IT-SOFC cathode.

  11. Fluorite Ce0.8Sm0.2O2- δ porous layer coating to enhance the oxygen permeation behavior of a BaCo0.7Fe0.2Nb0.1O3- δ mixed conductor

    Science.gov (United States)

    Wang, Tai-he; Song, Wei-jia; Li, Rong; Zhen, Qiang

    2016-06-01

    Fluorite Ce0.8Sm0.2O2- δ (SDC) nanopowder with a crystallite size of 15 nm was synthesized by a co-precipitation method. An SDC porous layer was coated onto a BaCo0.7Fe0.2Nb0.1O3- δ (BCFN) mixed conductor to improve its oxygen transport behavior. The results show that the SDC-coated BCFN membrane exhibits a remarkably higher oxygen permeation flux ({J_{{O_2}}}) than the uncoated BCFN in the partial oxidation of coke oven gas (COG). The maximum {J_{{O_2}}} value of the SDC-coated BCFN is 18.28 mL·min-1·cm-2 under a COG/air flux of 177 mL·min-1/353 mL·min-1 at 875°C when the thickness of the BCFN membrane is 1 mm; this {J_{{O_2}}} value is 23% higher than that of the uncoated BCFN membrane. This enhancement is likely because of the higher oxygen ionic conductivity of SDC, which supplies oxygen vacancies and accelerates oxygen exchange on the membrane/coating layer/gas three-phase boundary.

  12. BaMO3 (M=Zr, Hf, Sn) material dependence of Tc reduction in BaMO3-doped SmBa2Cu3Oy, films

    International Nuclear Information System (INIS)

    For the improvement of superconducting properties of BaMO3 (M=Zr, Sn, HQ-doped REBa2Cu3Oy films, we focused on the Tc reduction caused by lattice misfit between BaMO3 and REBa2Cu3Oy. We compared the influence on the Tc reduction of BaZrO3, BaSnO3 and BaHfO3-doped SmBa2Cu3Or (SmBCO) films with various BMO contents. From the correlation between configuration of nanorods and c-axis expansion, it was suggested that the lattice strain working on the SmBCO matrix became stronger in the order of BaHfO3, BaZrO3 and BaSnO3. Therefore, the combination of SmBCO and BaHfO3 is better regarding the suppression of the Tc reduction compared with other combinations of SmBCO and BaMO3.

  13. Assessment of microseeds biodegradability of Sm and Sm:Ba splenic implants in rabbits

    International Nuclear Information System (INIS)

    The radioactive interstitial implants have applications in controlling neoplasm in several regions of the human body. Currently the permanent brachytherapy seeds implanted in the spleen and other organs are made of I-125 seeds. After the total emission of radiation, the metal encapsulated seed remains inert in the implanted area. Seeds of bioactive ceramics have been prepared with Sm-152 incorporation to be activated in Sm-153. This study aimed to develop surgical technique for implanting biodegradable micro-seeds in the spleen of the rabbit. Three micro-seeds were introduced by hypodermic needle in the spleen in eight rabbits by median laparotomy. Subsequently, there were clinical and functional reactions of the animal to the implanted foreign body. The other objective was to perform the animal monitoring by radiography, produced in time sequence, and pathological studies of a fragment of the spleens of rabbits. The results show the effectiveness of surgery, the identification of the implanted material by radiography in vivo, and the biocompatibility of micro-seeds most of Sm and Sm:Ba. These seeds of reduced volume, 0.3x 1.6 mm, could be monitored for radiological studies in 2 periods: early and later implant. On the later studies, radiography was taken at 60d post-implant. Biopsies were taken and radiographs of the samples were also performed for evidencing the degradation state of the seeds. The results of the two groups of four rabbits are presented. They show partial degradation of the seed verified by radiographic contrast which is related to the atomic number of the elements and mass density in the seed. The biopsy showed that the ceramic is clearly absorbed by the spleen tissue and form tissue-implant interface. The histological slides showed an inflammatory reaction with presence of fibrosis of the giant cell foreign body. In conclusion, the radiograph shows a suitable noninvasive technique for monitoring the degradation of micro-seed ceramics in vivo

  14. Irradiation-induced reduction and luminescence properties of Sm2+ doped in BaBPO5

    International Nuclear Information System (INIS)

    Usually, Sm2+ ions could be reduced by heating the materials in reducing atmospheres. Exposure to ionizing radiations is also known to cause Sm3+→Sm2+ conversion. In this work, BaBPO5 doped with the samarium ion was prepared by high temperature solid-state reaction. Sm2+ ions were obtained by two different reduction methods, i.e., heating in H2 reduced atmosphere and X-ray irradiation. The measurements of X-ray diffraction (XRD), and scanning electron microscope (SEM) were investigated. It is found that the conversion of Sm3+→Sm2+ is very efficient in BaBPO5 hosts after X-ray irradiation. Sm2+ ions under these two reduction methods exhibit different characteristics that were studied by measurements of luminescence and decay. The results showed that the luminescence properties of Sm2+ ions in BaBPO5 were highly dependent on the sample preparation conditions. - Graphical abstract: The Sm doped in BaBPO5 as-prepared in air contains only Sm3+ ions and shows its fluorescence bands due to the 4G5/2 to 6H5/2, 6H7/2, 6H9/2, and 6H11/2 transitions (a) under the excitation of 488 nm Ar+-ion laser. The emission spectra of the samples after X-ray subsequentially irradiations are characteristic of Sm2+ transitions between the energy levels of 4f6 electronic configurations (b). It is found that the conversion of Sm3+→Sm2+ is very efficient in BaBPO5 hosts after X-ray irradiation

  15. Spectroscopy and luminescence dynamics of Ce3+ and Sm3+ in LiYSiO4

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Rui; Xu, Jinzhong; Liu, Guokui; Zhang, Xuejie; Zhou, Weihie; Pan, Fengjuan; Huang, Yan; Tao, Ye; Liang, Hongbin

    2016-03-03

    The lithium yttrium silicate series of LiY1-xLnxSiO4 exhibits superb chemical and optical properties, and with Ln = Ce3+, Sm3+, its spectroscopic characteristics and luminescence dynamics are investigated in the present work. Energy transfer and non-radiative relaxation dramatically influence the Ln3+ luminescence spectra and decay dynamics, especially in the Ce3+-Sm3+ co-doped phosphors. It is shown that thermal-quenching of the blue Ce3+ luminescence is primarily due to thermal ionization in the 5d excited states rather than multi-phonon relaxation, whereas cross-relaxation arising from electric dipole-dipole interaction between adjacent Sm3+ ions is the leading mechanism that quenches the red Sm3+ luminescence. In the co-doped systems, Ce3+-Sm3+ energy transfer in competing with the thermal quenching enhance the emission from Sm3+. The combined influences of concentration quenching, thermal ionization, energy transfer including cross-relaxation on the luminescence intensity of single-center and co-doped phosphors are analyzed based on the theories of ion-ion and ion-lattice interactions.

  16. Luminescence properties of phosphate phosphor Ba3Y(PO4)3:Sm3+

    International Nuclear Information System (INIS)

    A series of reddish orange-emitting phosphate phosphors Ba3Y1−x(PO4)3:xSm3+(0.01≤x≤0.20) were synthesized by solid-state reaction. X-ray diffraction and photoluminescence spectra were utilized to characterize the structure and luminescence properties of as-synthesized phosphors. The optimized phosphors Ba3Y0.95(PO4)3:0.05Sm3+ present several excitation bands from 300 to 500 nm, and exhibit intense reddish orange-emitting properties. The energy transfer type between Sm3+ ions was confirmed as d–d interaction by using Van Uitert model. The chromatic properties of the typical sample Ba3Y(PO4)3:0.05Sm3+ phosphor have been found to have chromaticity coordinates of (0.583, 0.405), which are located in reddish orange region under the excitation of 401 nm. These results indicated that Ba3Y(PO4)3:Sm3+ phosphors have potential applications in the field of lighting and display due to their effective excitation in the near-ultraviolet range. - Graphical abstract: The color coordinates for 5 mol% Sm3+ doped Ba3Y(PO4)3 phosphor were calculated to be (0.583, 0.405), which are located in reddish orange region under the excitation of 401 nm. The peaks of Ba3Y0.95(PO4)3:0.05Sm3+ phosphor with the highest emission intensity at 600 nm are broader than those of Y2O3:Eu3+ and Y2O2S:Eu3+ phosphors. All these characteristics suggest that Ba3Y(PO4)3:Sm3+ phosphors are suitable for near-UV (370–410 nm) excitation and can be applicable to near UV-based WLEDs. ▪ - Highlights: • Different concentration Sm3+-doped Ba3Y(PO4)3 phosphors were fabricated by solid state method. • The optimized phosphors present the several excitation bands from 300 to 500 nm. • The Ba3Y(PO4)3:Sm3+ shows bright reddish orange emissions under 401 nm excitation

  17. Hydrothermal synthesis and luminescent properties of BaMoO4:Sm3+ red phosphor

    Institute of Scientific and Technical Information of China (English)

    李兆; 王永锋; 曹静; 江元汝; 赵西成; 孟志新

    2016-01-01

    Trivalent samarium doped barium molybdate (BaMoO4:Sm3+) red phosphor was successfully synthesized by hydrothermal method. The crystal structure, morphology and photoluminescent property were characterized by X-ray diffraction, field environ-mental scanning electron microscopy and photoluminescence spectroscopy. The results indicated that the synthesized BaMoO4:Sm3+ phosphor consisted of a pure phase with an octahedral structure. The main excitation peaks were located at 362, 404, 445 and 477 nm, respectively, and were obviously observed. The main emission peaks were located at 533, 566, 602 and 646 nm, respectively. The phosphors exhibited a red performance at 646 nm, which was appropriate for the ultraviolet-light emitting diode (UV-LED) and blue LED. The luminescent intensity of BaMoO4:Sm3+ increased with an increase in the doping amount of Sm3+. The luminescent intensity had the optimal value forx=0.03. When the doping amount of Sm3+ was further increased, the concentration quenching phenomenon was observed. Monovalent lithium (Li+) cation was used as a charge compensator. The luminescence intensity first increased with in-creasing Li+ doping concentration, and then decreased. The optimal content of Li+ was about 2%. The BaMoO4:Sm3+ phosphor pre-pared in this study could act as superior red phosphor for white LEDs.

  18. Investigation of thermal neutron capture in 23Na, 138Ba, 140Ce and 142Ce

    International Nuclear Information System (INIS)

    A measurement of the angular correlation of γ-rays emitted in the capture of thermal neutrons in 23Na has been used to determine the multipole mixing ratio delta for seventeen transitions in 24Na, of which seven are primary transitions. For these primary transitions also the capture state spin admixture α has been derived. The neutron capture reaction proceeds predominantly through the Jsup(π)=1+ channel, as expected from previous cross-section measurements. A measurement of the circular polarization of γ-rays resulting from the capture of polarized thermal neutrons in 138Ba, 140Ce and 142Ce has yielded spin assignments for p-states in the final nuclei. Excitation energies and reaction Q-values have been obtained from the analysis of singles spectra taken with unpolarized neutrons. (Auth.)

  19. Preparation of double-doped BaCeO3 and its application in the synthesis of ammonia at atmospheric pressure

    Directory of Open Access Journals (Sweden)

    ZhiJie Li et al

    2007-01-01

    Full Text Available Perovskite-type oxides BaCe0.90Sm0.10O3−δ (BCS and BaCe0.80Gd0.10Sm0.10O3−δ (BCGS were synthesized by the sol–gel method and characterized by thermal analysis (TG-DTA, X-ray diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. Using the sintered samples as solid electrolytes and silver–palladium alloy as electrodes, ammonia was synthesized from nitrogen and hydrogen at atmospheric pressure in a solid-state proton-conducting cell reactor. The maximum rate of production of ammonia was 5.82×10−9 mol s−1 cm−2.

  20. Magnetization and heat capacity studies of double perovskite compounds Ba2SmRuO6 and Ba2DyRuO6

    International Nuclear Information System (INIS)

    Here we report the magnetic and heat capacity studies of the double perovskite compounds Ba2SmRuO6 and Ba2DyRuO6. Antiferromagnetic transitions are inferred at 54 and 47 K in Ba2SmRuO6 and Ba2DyRuO6, respectively, in the magnetization measurements. Heat capacity measurements show large jumps at the corresponding temperatures and confirm the bulk magnetic ordering. Both the measurements provide clear indication of the ordering of the rare earth moments also along with the Ruthenium moments. However, the heat capacity results suggest that the ordering of rare earth magnetic moments is spread over a large temperature range. An anomaly observed in the magnetization measurements at 42 K (below the magnetic ordering) in Ba2SmRuO6 is discerned as a reorientation of Sm3+ moments.

  1. Syntheses and characterization of Ln4Yb11Se22 (Ln = Ce, Sm, Gd)

    International Nuclear Information System (INIS)

    New interlanthanide selenides Ln4Yb11Se22 (Ln = Ce, Sm, Gd) were synthesized from reactions of their constituent elements at 1123 K. These ordered compounds are isostructural with Ce4Lu11S22, crystallizing with two formula units in the monoclinic space group C2/m. The structure consists of a network of six- and seven-coordinate Yb atoms penetrated by Ln2Se13 infinite chains. Gd4Yb11Se22 has an antiferromagnetic transition at T N = 2.29 K. Gd4Yb11Se22 is a semiconductor with a resistivity of 103 Ω cm at 298 K

  2. On the PL, TSL and OSL properties of SrS:Ce,Sm phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Lapraz, Dominique; Angellier, Gaelle [Laboratoire de Physique Electronique des Solides (LPES), Centre de Recherches sur les Solides et leurs Applications (CRESA), EA 1174, Faculte des Sciences, Universite de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 2 (France); Prevost, Hildegarde; Idri, Katia; Dusseau, Laurent [CEM2-CNRS UMR 5507, Universite de Montpellier II, Montpellier, Cedex 5 (France)

    2006-12-15

    The photoluminescence (PL), thermostimulated luminescence (TSL) and optical stimulated luminescence (OSL) properties of a cerium and samarium codoped strontium sulfide (SrS:Ce,Sm) used in OSL imaging devices are studied after UV or X-ray irradiation. A correlation is made between TSL and OSL results, showing a strong thermal and optical fading at room temperature, implying a significant instability of the OSL signal. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Photoluminescence properties of Sm2+-doped BaBr2 under hydrostatic pressure

    International Nuclear Information System (INIS)

    Photoluminescence spectra of Sm2+-doped BaBr2 have been measured under hydrostatic pressures up to 17 GPa at room temperature. In the low pressure range a red-shift of the broad 5d-4f transition of -145 cm-1/GPa is observed. From 5 to 8 GPa a phase mixture of the initial orthorhombic phase and the high-pressure monoclinic phase gives rise to two 5d-4f bands, which are strongly overlapping. Above 8 GPa the crystal is completely transformed to its high-pressure phase where two different Sm2+ sites exist, but only one broad 5d-4f transition is detected. It exhibits a red-shift of -36 cm-1/GPa. In addition, the line shifts of the 5D0→7FJ (J=0, 1, 2) transitions are investigated. Linear shifts of -19 cm-1/GPa for J=0, 2 and of -13 cm-1/GPa for J=1 are observed in the pressure range from 0 to 5 GPa. - Highlights: → Pressure-induced phase transition of BaBr2:Sm from orthorhombic to monoclinic. → BaBr2 phase transition is observed between 5 and 8 GPa. → Phase transition is monitored by photoluminescence spectroscopy. → Pressure-induced shift of the Sm2+ 5d-4f transition is analyzed.

  4. Luminescence and scintillation properties of BaF2sbnd Ce transparent ceramic

    Science.gov (United States)

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

    2016-08-01

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

  5. Effects of Ti4+ Ions on Fluorescence Properties of Sr2CeO4:Sm3+ Phosphors.

    Science.gov (United States)

    Jiao, Haiyan; Wang, Peiyu; Liu, Liwei; Wang, Yuhua

    2016-04-01

    Ti4+-doped Sr2CeO4:Sm3+ phosphors were synthesized with the solid-state reaction method and the effects of doping Ti4+ on the photoluminescence properties were investigated in detail. A broad excitation band ascribed to the O2- -Ce4+ transition was observed in the range of 200 to 400 nm and with doping Ti4+ nto Ce4+ sites, the intensity of charge transfer band of O2- --> Ce4+ (300-370 nm) was significantly broaden and enhanced. As a result, the emission intensity of Sr2Ce1-xTixO4 has improved about 85% by doping 0.01 mol Ti4+. White emission of Sr2-yCe0.99Ti0.01O4:ySm3+ at y O2- CT emission and 4G5/2-6HJ Sm3+ transitions whereas only the Sm3+ red emission prevails for 0.03 phosphor exhibited excellent color purity. Its chromaticity coordinate is measured to be (0.326, 0.322), which is close to the pure white (0.33, 0.33). The results showed that Sr1.99Ce0.99Ti0.01O4: 0.01 Sm3+ phosphors could be considered as a potential single-phase white-emitting phosphor for white light-emitting diodes. PMID:27451755

  6. Melt process of Sm-Ba-Cu-O bulk superconductors by thin film cold seeding

    International Nuclear Information System (INIS)

    We discuss Sm123 bulks melt-processed in air and their characteristic superconducting properties for improving superconducting properties and producing a larger bulk. Isothermal undercooling growth in air with oxygen annealing and Nd123/MgO thin film cold seeding technique were applied in SmBaCuOy/Ag system to seek the high-efficiency of process, homogeneity of composition, and feasibility of batch production. We investigated process conditions such as heat treatment temperatures, compositions, seeding methods, and atmosphere. Single-domain growth of superconducting phases of a square larger than 10 mm on a side and 5 mm in thickness was achieved using this technique. Tc,onset and Tc,zero are 94 and 90 K, and Jc is 3 x 104 A/cm2 at around 2 T at 77 K with a typical peak effect in the LRE system. In the case of Sm211 = 10 and 40 mol% addition, the maximum trapped magnetic field of the bulks is 1000 and 2100 G, respectively. The maximum magnetic field increases as Sm211 volume fractions increase. The result implies that melt-processed in air applying isothermal method and thin film seeding in Sm system is feasible for producing larger bulks in large scale applications

  7. Charge traps in Ce-doped CaF2 and BaF2

    OpenAIRE

    Drozdowski, Winicjusz; Przegi��tka, Krzysztof; Wojtowicz, Andrzej J; Oczkowski, Hubert Lucjan

    1999-01-01

    Thermoluminescence of CaF2:Ce, BaF2, and BaF2:Ce irradiated at room temperature is reported. X-ray induced emission spectra of the samples show that both excitonic (due to e- + VK recombination) and Ce3+ d-f luminescence may contribute to thermoluminescence signal. The simple Randall-Wilkins model is used to deconvolute glow curves into seven to eight first-order peaks. Parameters of all traps are calculated and correlations between peaks in the curves of the examined materials are discussed.

  8. Doping effects on protonic conduction in SrCeO3- and BaCeO3 - based perovskites

    International Nuclear Information System (INIS)

    One studied the electric conductivity of SrCe1-xMxO3 and BaCe1-xMxO3 (M - rare-earth elements) proton conductors with the perovskite structure depending on the doping level. Occurrence of maximums and minimums of the proton conductivity was explained on the basis of the typical conductivity was explained on the basis of the typical structure variations of the lattice under doping. One studied the anomalies of BaCe1-xErxO3 ceramics properties within two-phase range on the basis of the concepts about percolation clusters. It is shown, that mobility percolation types in proton-conducting thin films and ceramics should differ essentially

  9. MgO:Li,Ce,Sm as a high-sensitivity material for Optically Stimulated Luminescence dosimetry

    Science.gov (United States)

    Oliveira, Luiz C.; Yukihara, Eduardo G.; Baffa, Oswaldo

    2016-04-01

    The goal of this work was to investigate the relevant dosimetric and luminescent properties of MgO:Li3%,Ce0.03%,Sm0.03%, a newly-developed, high sensitivity Optically Stimulated Luminescence (OSL) material of low effective atomic number (Zeff = 10.8) and potential interest for medical and personal dosimetry. We characterized the thermoluminescence (TL), OSL, radioluminescence (RL), and OSL emission spectrum of this new material and carried out a preliminary investigation on the OSL signal stability. MgO:Li,Ce,Sm has a main TL peak at ~180 °C (at a heating rate of 5 °C/s) associated with Ce3+ and Sm3+ emission. The results indicate that the infrared (870 nm) stimulated OSL from MgO:Li,Ce,Sm has suitable properties for dosimetry, including high sensitivity to ionizing radiation (20 times that of Al2O3:C, under the measurement conditions) and wide dynamic range (7 μGy–30 Gy). The OSL associated with Ce3+ emission is correlated with a dominant, practically isolated peak at 180 °C. Fading of ~15% was observed in the first hour, probably due to shallow traps, followed by subsequent fading of 6–7% over the next 35 days. These properties, together with the characteristically fast luminescence from Ce3+, make this material also a strong candidate for 2D OSL dose mapping.

  10. Photoluminescence and thermally stimulated luminescence properties of CaSO{sub 4}:Sm{sup 3+} and CaSO{sub 4}:Ce{sup 3+},Sm{sup 3+}; Sm{sup 3+} {yields} Sm{sup 2+} conversion and high temperature dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Prevost, Hildegarde; Dusseau, Laurent [Institut d' Electronique du Sud (IES), UMR UM2-CNRS 5214, Universite de Montpellier II, Place Eugene Bataillon - CC 083, 34095 Montpellier Cedex 5 (France); Angellier, Gaelle; Mady, Franck; Benabdesselam, Mourad [Laboratoire de Physique Electronique des Solides (LPES), Centre de Recherches sur les Solides et leurs Applications (CRESA), EA 1174, Faculte des Sciences, Universite de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 2 (France); Lapraz, Dominique

    2007-12-15

    The photoluminescence (PL) and thermally stimulated luminescence (TSL) properties of CaSO{sub 4}:Sm and CaSO{sub 4}:Ce,Sm are studied. After X irradiation of CaSO{sub 4}:Sm, an obvious Sm{sup 3+}/Sm{sup 2+} redox process is observed. The Ce co-doping is responsible for the presence of an intense TSL peak at about 485/500 C, showing an interesting application in high temperature radiation dosimetry. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Crystal structure of the RLiGe2 (R=La,Ce,Pr,Nd,Sm,Eu) compounds

    International Nuclear Information System (INIS)

    Crystal structure of RLiGe2 compounds is determined by the method of monocrystal and powder. Lattice periods specified according to diffraction pattern (DRON)-3, CuKα-radiation) are equal to a=0.7815(3), b=0.3965(2), c1.0748(4) nm (for CeLiGe2 compound), sp. gr. Pnma. The structure was interpreted by SM-4 computer. Divergency factor for 154 hkl reflexes equals 0.117. The structure belongs to CaZiGe2 structural type. Isostructural CeLiGe2 compounds form with La, Pr, Nd, Sm, Eu

  12. Improvement of critical current densities in SmBa2Cu3Oy, films with BaHfO3 nano-rods using low temperature growth technique

    International Nuclear Information System (INIS)

    We studied growth substrate temperature dependent morphologies of BaHfO3 (BHO) nano-rods for SmBa2Cu3Oy, (SmBCO) films with BHO fabricated by pulsed laser deposition (PLD) method. The morphology of BHO nano-rods within the SmBCO matrix could be controlled by changing substrate temperatures adoping a Low Temperature Growth (LTG) technique. Using the LTG technique, we could fabricate SmBCO films showed c-axis orientation even at low substrate temperature during deposition without a degradation of superconducting properties, which is one of the most advantages of the LTG technique. In this study, we found an optimal morphology of the BHO nano-rods and the morphology was fine, straight and various growth directions. The BHO nano-rods were more effective to improve the Jc in a magnetic field than other morphologies of the BHO nano-rods.

  13. New phases in the Ba-Ce(M)-O systems (M = Ga, In)

    OpenAIRE

    Matskevich, N. I.; Chupahina, T. I.; Bazuev, G. V.; Kuznetsov, F. A.

    2005-01-01

    A new and known barium cerates doped by In and Ga were synthesized in air at 1700 K. The synthesis was performed by solid state reactions from BaCO3, CeO2, In2O3 or Ga2O3. X-ray diffraction profiles of the powdered samples were obtained with DRON-UM-1 and STADI-P diffractometers using monochromatized CuKa radiation. The following compositions of new phases were obtained: BaCe1-xGaxO3-d (x = 0.05; 0.1) and BaCe1-xInxO3-d (x = 0.25, 0.5). They crystallize in the orthorhombic space group Pnma. T...

  14. Mechanical properties of Sm-Ba-Cu-O bulk superconductors at room temperature

    International Nuclear Information System (INIS)

    In order to investigate the mechanical properties of Sm-Ba-Cu-O bulk superconductors fabricated using TSMG method such that Sm123:Sm211 in molar ratio was 100-Z:Z (Z=16.7, 28.6), tensile tests in the direction perpendicular to the c-axis have been carried out at room temperature by using the small specimens cut from the bulk samples. Although, non-linear behavior was seen in a few specimens, stress-strain curves were almost linear until the fracture. The non-linear behavior is presumably ascribed to the opening of pre-existing micro-cracks parallel to the c-axis and the slow propagation of them. The Young's modulus for both samples was almost equal. Poisson's ratio based on the transverse strain parallel to the c-axis was smaller than that based on the strain perpendicular to it. One of the possible reasons for it will be the reduced transverse shrinkage by the constraint at the interface between the specimen and the aluminum alloy tensile rod coupled with the opening of the pre-existing micro-cracks perpendicular to the c-axis. Tensile strength for the sample with 28.6 mol% of Sm211 was not higher than that with 16.7 mol%. It is presumably ascribed to the low cohesive force between the Sm211 particles and the matrix. The effect of loading condition with respect to that of the crystal growth on the strength was not clear. No significant difference in the strength was found between the specimens including a growth sector boundary and those without it

  15. Photocatalytic CO2 reduction of BaCeO3 with 4f configuration electrons

    Science.gov (United States)

    Wang, Jun; Huang, Chunxiang; Chen, Xianliu; Zhang, Haitao; Li, Zhaosheng; Zou, Zhigang

    2015-12-01

    The perovskite-type photocatalyst BaCeO3, prepared by a Pechini method, was investigated for CO2 reduction under UV light irradiation. The prepared samples were characterized by X-ray diffraction, BET surface area measurement, UV-vis reflectance spectroscopy, scanning electron microscopy, and transmission electron microscopy, and the flat band potential was confirmed by Mott-Schottky measurements. The effects of various cocatalyst nanoparticles (Ag, Au, Pt, CuO, and RuO2) on the photocatalytic activities of BaCeO3 were also discussed. Among these cocatalysts, Ag nanoparticles exhibited the best performance for improving the photocatalytic activities of CO2 reduction.

  16. Elastic and Piezoelectric Properties of Ce:BaTiO3 Single Crystals

    Institute of Scientific and Technical Information of China (English)

    DING Shuo; ZHU Yong; LIU Yu-Long; SIU G. G.; LEE C. M.; JIANG Yi-Jian

    2005-01-01

    @@ Laser Brillouin scattering is applied to measure the sound velocity and the sound anisotropic velocity in highquality single-domain tetragonal Ce:BaTiO3 single crystals at room temperature. The elastic and piezoelectric constants are thus determined. Based on the sound propagation equations and these results, the directional dependence of the compressional and shear modulus of Ce:BaTiO3 in the (010) and (001) planes are investigated.Some properties of sound propagation and electromechanical coupling in the crystal are discussed.

  17. Effects of Nd, Sm, Gd, Dy, Er Dopant on Electrical Properties of BaTiO3 Ceramics

    Institute of Scientific and Technical Information of China (English)

    Hao Sue; Wei Yongde; Xing Xiaoxu

    2004-01-01

    BaTiO3 ceramics doped with various quantities of Nd2O3, Sm2O3, Gd2O3, Dy2O3 and Er2O3 were prepared respectively ( the adulterate concentrations were 0. 001,0. 002, 0. 003, 0.005, 0. 007 mol fraction) through a sol-gel method and their electrical properties were researched. It is found that each adulteration of Nd2O3, Sm2O3 Gd2O3,Dy2O3 and Er2O3 all can make the resistivity of BaTiO3 ceramics decline , especially Sm2O3 and Gd2O3. When the addition of Sm2O3 is 0. 001 mol, the resistivity is the smallest, declining from 4.0 × 1012 to 6.5 × 103 Ω different kind of rare earth exhibits different regularity. The grain resistance of BaTiO3 ceramics doped with Sm2O3 or Gd2O3 exhibits a NTC effect, at the same time the grain boundary resistance has a PTC effect, and the grain boundary resistance is much larger than the grain resistance, so the PTC effects of BaTiO3 ceramics doped with Sm2O3 or Gd2O3 originate from the grain boundary. The additions of Nd2O3 , Gd2O3 or Er2O3 make the dielectric constant and the dielectric loss of BaTiO3 ceramics change evidently, especially Nd2O3. The dielectric constant is larger than that of pure BaTiO3 ceramics, on the other hand, the dielectric loss is much lower, which is useful in capacitor fields.

  18. Thermoelectric properties of molybdenum oxides LnMo(8)O(14) (Ln = La, Ce, Pr, Nd and Sm)

    DEFF Research Database (Denmark)

    Xu, Jianxiao Jackie; Sonne, Monica; Pryds, Nini;

    2010-01-01

    The series LnMo8O14 (Ln = La, Ce, Pr, Nd and Sm) containing bicapped Mo8 clusters was synthesized via solid state reaction at 1673 K. Oxides of this type were reported to be narrow gap semiconductors. Our Seebeck coefficient measurements show that some of these reduced molybdenum oxides exhibit a...

  19. New oxocompounds with planar coordinated Pd2+ BaPdNd2O5 and BaPdSm2O5

    International Nuclear Information System (INIS)

    Single crystals of BaPdNd2O5(A), BaPdSm2O5(B) and BaCuNd2O5(C) were prepared by solid state reaction using BaCl2 as a fusing assistant (A, B) or by high temperature Laser technique (C). X-ray investigations show tetragonal symmetry with A: a=6.7387(5), c=5.9002(25)A, B: a=6.6667(13), c=5.8800(6)A (space group D4sub(4h) - P4/mbm, Z=2). The formerly investigated compound (C) is refined here by single crystal data. (A) and (B) belong to the BaPtNd2O5-type. The results are discussed. (Author)

  20. SmBa2NbO6 Nanopowders, an Effective Percolation Network Medium for YBCO Superconductors

    Directory of Open Access Journals (Sweden)

    S. Vidya

    2013-01-01

    Full Text Available The percolation behavior of superconductor-insulator composite, YBa2Cu3O7–δ, and nano SmBa2NbO2 synthesized by modified combustion technique was studied. Particle size of nano SmBa2NBO6 was determined using transmission electron microscopy. The chemical nonreactivity of nano SmBa2NbO6 with YBCO is evident from the X-Ray diffraction study which makes it a suitable nanoceramic substrate material for high temperature superconducting films. A systematic increase in the sintered density, approaching the optimum value of the insulating nanophase is clearly observed, as the vol.% of YBCO in the composite decreases. SEM micrograph showed uniform distribution of nanopowder among the large clusters of YBCO. The obtained percolation threshold is ~26 vol% of YBCO in the composite. All the composites below the threshold value showed TC(0~92 K even though the room resistivity increases with increase in vol.% of nano SmBa2NbO6. The values of critical exponents obtained matches well with the theoretically expected ones for an ideal superconductor-insulator system.

  1. Photoelectrochemical study of lanthanide zirconium oxides, Ln2Zr2O7 (Ln = La, Ce, Nd and Sm)

    International Nuclear Information System (INIS)

    Photocatalytic activities for hydrogen evolution of lanthanide zirconium oxides, Ln2Zr2O7 (Ln = La, Ce, Nd and Sm) prepared by a solution reaction method were investigated. Under the illumination of 500 W Xenon lamps, hydrogen gas was clearly evolved in a distilled water suspension of La2Zr2O7, Sm2Zr2O7 and Nd2Zr2O7. Under the visible-light illumination, hydrogen gas was evolved in a distilled water suspension of Nd2Zr2O7 and Sm2Zr2O7. From the photoelectrochemical measurements, the values of the flat band potential were estimated to be -0.64, -0.52, -0.31 and +0.04 eV for La2Zr2O7, Sm2Zr2O7, Nd2Zr2O7 and Ce2Zr2O7, respectively, versus the normal hydrogen electrode (NHE). The values of the band gap energy were calculated to be about 3.52, 2.86, 2.67 and 2.53 eV for La2Zr2O7, Sm2Zr2O7, Nd2Zr2O7 and Ce2Zr2O7, respectively. Due to the effect of 4f orbital electrons, the band gap energy of these compounds becomes narrower than in ZrO2 and as a consequence, Sm2Zr2O7 and Nd2Zr2O7 show the photocatalytic activity under the visible-light

  2. Thermoelectric properties of molybdenum oxides LnMo8O14 (Ln = La, Ce, Pr, Nd and Sm)

    International Nuclear Information System (INIS)

    The series LnMo8O14 (Ln = La, Ce, Pr, Nd and Sm) containing bicapped Mo8 clusters was synthesized via solid state reaction at 1673 K. Oxides of this type were reported to be narrow gap semiconductors. Our Seebeck coefficient measurements show that some of these reduced molybdenum oxides exhibit a thermopower of above -100 μV/K at room temperature, which is promising for the thermoelectric application. The highest power factor of 71 μW/mK2 was obtained for SmMo8O14 at 1152 K.

  3. Study on Preparation and Electrical Properties of Ba1.03 Ce0.2O3-α Solid Electrolyte

    Institute of Scientific and Technical Information of China (English)

    仇立干; 马桂林; 闻荻江

    2004-01-01

    Ba1.03Ce0.8Eu0.2O3-α solid electrolyte with nonstoichiometric composition was prepared by high temperature solid-state reaction. Phase composition,surface and fracture morphologies of the specimen were characterized by using XRD and SEM,respectively. Ionic conduction was researched by gas concentration cell,the performance of hydrogen-air fuel cell was measured in the temperature range of 600~1000 ℃,and compared them with those of BaCe0.8Eu0.2O3-α and Ba0.98Ce0.8Eu0.2O3-α. The results indicate that Ba1.03Ce0.8Eu0.2O3-α is a single-phase perovskite-type orthorhombic system. It is a pure proton conductor in the temperature range of 600~1000 ℃ in hydrogen atmosphere,and its proton conduction is superior to that of BaCe0.8Eu0.2O3-α and Ba0.98Ce0.8Eu0.2O3-α. It is a mixed conductor of oxide ion and electron hole in oxygen atmosphere. At 1000 ℃,the performance of the fuel cell in which Ba1.03Ce0.8Eu0.2O3-α as electrolyte is higher than that of BaCe0.8Eu0.2O3-α or Ba0.98Ce0.8Eu0.2O3-α.

  4. Flux pinning properties in high magnetic field and low temperature of SmBa2Cu3Oy thin films

    International Nuclear Information System (INIS)

    We have studied SmBa2Cu3Oy (Sm123) thin films fabricated by low temperature growth (LTG) technique. The critical current densities (Jcs) in magnetic fields at 77 K of the LTG-Sm123 film embedded nanosized low-Tc particles (NLP) were comparable to that of NbTi wire at 4.2 K. Furthermore, at low temperatures of 65 and 40 K, the Jc-B curves of the LTG-Sm123 film were superior to even that of Nb3Sn wire at 4.2 K and the anomalous peaks were observed on the Jc-B and Fp-B curves. Based on the scaling of the flux pinning force, we found that fluxes in the film would be pinned at grain boundary mainly and the anomalous peaks were caused by the NLP

  5. Interlayer magnetotransport study in electron-doped Sm2-CeCuO4-

    Indian Academy of Sciences (India)

    Takasada Shibauchi; Tsuyoshi Kawakami; Yuhki Terao; Minoru Suzuki; Lia Krusin-Elbaum

    2006-01-01

    Vortex and pseudogap states in electron-doped Sm2-CeCuO4- ( ∼ 0.14) are investigated by the interlayer transport in magnetic fields up to 45 T. To extract intrinsic properties, we fabricated small 30 nm-high mesa structures, sufficiently thin to be free of the recently reported partial decomposition problems. On cooling, the -axis resistivity ρc of the mesa structures reveals a semiconductive upturn above c, followed by a sharp superconducting transition at 20 K. When the magnetic field is applied along the -axis, ρc() shows a parallel shift without significant broadening, as also observed in the hole-doped underdoped cuprates. Above the transition we observe negative magnetoresistance (MR), which can be attributed to the field suppression of the pseudogap, whose magnitude is as small as 38 K. Our results in the ∼ 0.14 samples closely correspond to the interlayer transport behavior in the `overdoped' regime of hole-doped Bi2Sr2CaCu2O8+.

  6. Luminescence of BaAl2O4:Mn2+,Ce3+ phosphor

    International Nuclear Information System (INIS)

    Powder samples of barium aluminate doped with Mn2+ and Ce3+ were prepared by solid-state reaction method and their photoluminescence and thermoluminescence properties were studied. Substitution of Ca/Sr in place of Ba resulted in enhanced emission from Ce3+ ions without changing the spectral profile. Cerium efficiently sensitized the manganese luminescence in barium aluminate. Photoluminescence and thermo luminescence observations have indicated the presence of Vk3+ defects in undoped barium aluminate. However, Barium aluminate (either undoped or doped with manganese) did not exhibit long afterglow

  7. Stress effect on Raman spectra of Ce-doped BaTiO3 films

    Science.gov (United States)

    Chen, M. S.; Shen, Z. X.; Tang, S. H.; Shi, W. S.; Cui, D. F.; Chen, Z. H.

    2000-08-01

    Ce-doped BaTiO3 (BTO:Ce) thin films prepared on MgO (100) substrates by pulsed laser deposition (PLD) at oxygen pressure of 1.2×10-3 and 17 Pa have been studied by micro-Raman spectroscopy, x-ray diffraction (XRD) and atomic force microscopy (AFM). The film deposited at lower oxygen pressure has a larger lattice parameter in the direction normal to the substrate surface, and the film has smaller grains and a smoother surface. The polarized Raman peaks of both as-deposited films show blue shifts and linewidth broadening in comparison to those of the BaTiO3 single crystal. The blue shifts are attributed to tensile stresses in the films. Our results indicate that the grain size increases and the tensile stress relaxes with annealing. We have shown that quantum confinement and oxygen vacancies are not the dominant factors for the observed Raman spectral changes.

  8. 95 K Sm1+xBa2-xCu3Oz single crystal with controlled stoichiometry grown under 1 atm oxygen pressure

    International Nuclear Information System (INIS)

    In this communication, for the first time, we report on a high-Tc 95 K Sm1+xBa2-xCu3Oz (SmBCO) single crystal with a small transition width of less than 0.5 K grown under 1 atm oxygen pressure. We found that the substitution of Ba by Sm could be effectively suppressed by using liquid composition control. Jc-B curves and scaling analysis of samples at 77 K with B-vector parallel c indicate that a delta Tc style defect is the predominant pinning in SmBCO crystals. (rapid communication)

  9. Tillandsia usneoides L, a biomonitor in the determination of Ce, La and Sm by neutron activation analysis in an industrial corridor in Central Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Isaac-Olive, K. [Facultad de Medicina. Universidad Autonoma del Estado de Mexico, Paseo Tollocan s/n, esq. Jesus Carranza, Toluca, 50120 Estado de Mexico (Mexico); Solis, C., E-mail: corina@fisica.unam.mx [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 04510 Mexico DF (Mexico); Martinez-Carrillo, M.A; Andrade, E. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 04510 Mexico DF (Mexico); Lopez, C.; Longoria, L.C. [Instituto Nacional de Investigaciones Nucleares (ININ), Salazar, 50045 Estado de Mexico (Mexico); Lucho-Constantino, C.A. [Universidad Politecnica de Pachuca, Carretera Pachuca-Cd. Sahagun, Km. 20., Hidalgo, Mexico (Mexico); Beltran-Hernandez, R.I. [Centro de Investigaciones Quimicas, Universidad Autonoma del Estado de Hidalgo. Carretera Pachuca-Tulancingo km. 4.5, 42184, Pachuca, Hidalgo (Mexico)

    2012-04-15

    The atmosphere of the Tula Industrial Corridor in Central Mexico is contaminated due to several industries including oil refining while station monitoring in this area are limited. Lanthanides are considered fingerprint of oil refinery activities, and La, Ce and Sm have been previously detected in this area using filters. The suitability of T. usneoides as a biomonitor assessing the La, Ce and Sm concentrations in Particulate Matter is evaluated by NAA. Results of both biomonitor and filters are highly correlated.

  10. Tillandsia usneoides L, a biomonitor in the determination of Ce, La and Sm by neutron activation analysis in an industrial corridor in Central Mexico

    International Nuclear Information System (INIS)

    The atmosphere of the Tula Industrial Corridor in Central Mexico is contaminated due to several industries including oil refining while station monitoring in this area are limited. Lanthanides are considered fingerprint of oil refinery activities, and La, Ce and Sm have been previously detected in this area using filters. The suitability of T. usneoides as a biomonitor assessing the La, Ce and Sm concentrations in Particulate Matter is evaluated by NAA. Results of both biomonitor and filters are highly correlated.

  11. Comparative performances of LaBr3(Ce) and BaF2 scintillators

    International Nuclear Information System (INIS)

    Inorganic scintillation detectors have wide applications in nuclear spectroscopy, medical imaging, space science, geological exploration etc. The detectors that are recently attracted to the nuclear and particle physics experimentalists are La-halide, Lu2SiO5 (LSO) and BaF2 because of their superior energy and time resolutions. A BaF2 detector is known to have very good timing properties because of its ultrafast decay time component (600 ps) but a poor energy resolution (∼10% at 662 keV). On the other hand, La-halide detectors have subnanosecond time resolutions as well as excellent energy resolution because of their high light output and faster scintillation decay time (16 ns). Here, we have performed comparative studies of LaBr3(Ce) and BaF2 detectors with same crystal sizes (38 x 25 mm2)

  12. Heavy elements Ba, La, Ce, Nd, and Eu in 56 Galactic bulge red giants

    CERN Document Server

    Van der Swaelmen, M; Hill, V; Zoccali, M; Minniti, D; Ortolani, S; Gomez, A

    2016-01-01

    Aims. The aim of this work is the study of abundances of the heavy elements Ba, La, Ce, Nd, and Eu in 56 bulge giants (red giant branch and red clump) with metallicities ranging from -1.3 dex to 0.5 dex. Methods. We obtained high-resolution spectra of our giant stars using the FLAMES-UVES spectrograph on the Very Large Telescope. We inspected four bulge fields along the minor axis. Results. We measure the chemical evolution of heavy elements, as a function of metallicity, in the Galactic bulge. Conclusions. The [Ba, La, Ce, Nd/Fe] vs. [Fe/H] ratios decrease with increasing metallicity, in which aspect they differ from disc stars. In our metal-poor bulge stars, La and Ba are enhanced relative to their thick disc counterpart, while in our metal-rich bulge stars La and Ba are underabundant relative to their disc counterpart. Therefore, this contrast between bulge and discs trends indicates that bulge and (solar neighbourhood) thick disc stars could behave differently. An increase in [La, Nd/Eu] with increasing m...

  13. Tunable luminescence properties and energy transfer in Ba3Lu(PO4)3:Ce3+,Tb3+ phosphors

    International Nuclear Information System (INIS)

    Highlights: • Effective energy transfer from Ce3+ to Tb3+ in Ba3Lu(PO4)3 was confirmed. • The reason of energy transfer from Ce3+ to Tb3+ was investigated in detail. • Ba3Lu(PO4)3:Ce3+, Tb3+ can be a potential green-emitting phosphor for UV LEDs. - Abstract: A series of novel color-tunable phosphors Ba3Lu(PO4)3:Ce3+,Tb3+ have been synthesized by solid-state reaction. X-ray diffraction, photoluminescence emission and excitation spectra, lifetime, as well as the effect of Tb3+ concentration were employed to characterize the resulting samples. The emission spectra of Ba3Lu(PO4)3:Ce3+,Tb3+ phosphor contains both the asymmetric broad-band Ce3+ ion emission and the line-type Tb3+ ion emission. Under ultraviolet light excitation, Ba3Lu(PO4)3:Ce3+,Tb3+ can achieve tunable emission from deep blue to yellowish-green by changing the concentration of Tb3+. The results indicated that these phosphors could be considered as double emission phosphors for field emission displays

  14. Ferroelectricity and ferromagnetism near room temperature: a multilayer engineering of SmFeO3-BaTiO3

    International Nuclear Information System (INIS)

    The search for new materials with high magnetocapacitance (MC) near room temperature is one of the central issues in modern electronics, because large MC typically brings in a new functionality of tuning capacitance by applying magnetic field. It is very difficult to achieve ferroelectricity and ferromagnetism simultaneously. We have engineered a multilayer film of promising functional properties with standard ferroelectric (BaTiO3) and anti-ferromagnetic (SmFeO3) material. SmFeO3-BaTiO3 multilayer film was grown on a Si (100) substrate using pulsed laser deposition (PLD) technique. During deposition process, oxygen pressure of the PLD chamber (Neocera, USA) was maintained at 10 mTorr. The energy of laser (Model No: CompexPro 205 F, KrF) was set to 100 mJ (wave length=248 nm). Target to substrate distance was set to 6 cm and substrate temperature was maintained at 350℃. Sintered pellets of BaTiO3 and SmFeO3 (Aldrich, 99.9%) were used as the source of the PLD target. The repetition rate of laser pulse was 10 Hz and 25000 numbers of pulses was used for each layer. Thickness of the film was ∼ 209 nm, as obtained from SEM picture. Magnetic hysteresis loop exhibits typical signature of a soft ferromagnetic character at room temperature in contrast to that observed in antiferromagnetic bulk counterpart. Detailed magnetoelectric analysis is under process for final conformation. (author)

  15. Sputter deposition of Ce(Sm,Y)O2 thin films: linking phase instability to grain size

    Science.gov (United States)

    Van Steenberge, S.; Depla, D.

    2016-06-01

    (1  ‑  x)CeO2  ‑  xMO1.5 thin films (with M  =  Y or Sm) were deposited using DC reactive dual magnetron sputtering. The influence of the substitution of Ce4+ ions by M3+ ions in the ceria fluorite structure is investigated with x-ray diffraction and scanning electron microscopy to provide a description of the thin film microstructural and textural evolution at room temperature and at elevated temperatures. Phase analysis shows that the fluorite structure can be maintained until a composition of x  =  0.40 of Y or Sm. At higher values of x, a diphasic region is observed. The films are thermally stable because no restructuring occurs when they are heated. A decrease in grain size is observed before the diphasic region forms which is typically explained from a reduced adatom mobility. However, the microstructure throughout the composition range is indicative of zone T growth. These findings illustrate that while the growth of a thin film is a kinetically driven process, the observed decrease in grain size is no evidence of a reduced surface adatom mobility but of imposed thermodynamic barriers. The critical composition for the grain size change coincides not only for both material systems (M  =  Y or Sm), but also with reported values of crystallographic structural changes in bulk material.

  16. Influences of Zr, Ce and Ba fission products on the surface properties of UO2: Atomistic simulations

    Science.gov (United States)

    Xiao, Hongxing; Long, Chongsheng; Tian, Xiaofeng; Chen, Hongsheng

    2016-07-01

    Molecular dynamics (MD) simulations with a shell-core model have been carried out to investigate the influences of Zr, Ce and Ba fission products on the surface properties of UO2. Simulation results indicate that (i) the presence of these fission products will change the surface energy of three low-index surfaces in UO2; (ii) the individual addition of Ce has no significant effect on the surface energy, while the individual addition of Ba will dramatically decrease the surface energy of UO2 by approximately 18% on (100) surface, 7% on (110) surface and 9% on (111) surface with the Ba contents ranging from 0 to 12.5 mol% at 300 K, which is obviously contrary to the Zr; (iii) the combined additions of Zr, Ce and Ba fission products will continuously increase the surface energy of UO2 (100), (110) and (111) surfaces; (iv) the structures of the three low-index surfaces in pure UO2 as well as U0.8(Zr, Ce, Ba)0.2O2 are dramatically disturbed after the free relaxation; (v) The nearest O atoms move towards the Zr and Ce atoms center by about 0.21 Å and 0.12 Å but move away from the Ba atom center by about 0.27 Å.

  17. Diffusion of Zr, Ru, Ce, Y, La, Sr and Ba fission products in UO2

    International Nuclear Information System (INIS)

    The diffusivity of the solid fission products (FP) Zr (Zr4+), Ru (Ru4+, Ru3+), Ce (Ce4+), Y (Y3+), La (La3+), Sr (Sr2+) and Ba (Ba2+) by a vacancy mechanism has been calculated, using a combination of density functional theory (DFT) and empirical potential (EP) calculations. The activation energies for the solid fission products are compared to the activation energy for Xe fission gas atoms calculated previously. Apart from Ru, the solid fission products all exhibit higher activation energy than Xe. For all solid FPs except Y3+, the migration of the FP has lower barrier than the migration of a neighboring U atom, making the latter the rate limiting step for direct migration. An indirect mechanism, consisting of two successive migrations around the FP, is also investigated. The calculated diffusivities show that most solid fission products diffuse with rates similar to U self-diffusion. However, Ru, Ba and Sr exhibit faster diffusion than the other solid FPs, with Ru3+ and Ru4+ diffusing even faster than Xe for T < 1200 K. The diffusivities correlate with the observed fission product solubility in UO2, and the tendency to form metallic and oxide second phase inclusions

  18. Structural and 121Sb M\\"ossbauer Spectroscopic Investigations of the Antimonide Oxides REMnSbO (RE = La, Ce, Pr, Nd, Sm, Gd, Tb) and REZnSbO (RE = La, Ce, Pr)

    OpenAIRE

    Schellenberg, Inga; Nilges, Tom; Pöttgen, Rainer

    2008-01-01

    The quaternary antimonide oxides REMnSbO (RE = La, Ce, Pr, Nd, Sm, Gd, Tb) and REZnSbO (RE = La, Ce, Pr) were synthesized from the RESb monoantimonides and MnO, respectively ZnO. We report on single crystal X-ray data and a detailed 121Sb M\\"ossbauer spectroscopic investigation.

  19. Investigation about thermophysical properties of Ln2Ce2O7 (Ln = Sm, Er and Yb) oxides for thermal barrier coatings

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted Highlights: ► We successfully prepared three types of new rare earth cerium oxides. ► We measured their thermophysical properties. ► These new ceramics can be explored as candidate ceramics for thermal barrier coatings. -- Abstract: Three kinds of rare earth cerium oxides – Ln2Ce2O7 (Ln = Sm, Er and Yb) were prepared by solid state reaction method. Their phase compositions, microstructures and thermophysical properties were investigated. Results of X-ray diffraction reveal that pure Ln2Ce2O7 (Ln = Sm, Er and Yb) oxides with fluorite structure are successfully synthesized in the current research. Scanning electrical microscopy results show that their microstructures are dense and no other un-reacted oxides or inter-phases exist in the interfaces between grains. Their thermal expansion coefficients are higher than those of YSZ, while their thermal conductivities are lower than those of YSZ. The decreasing ionic radius from Sm3+ to Yb3+ results in the descending thermal expansion coefficients from Sm2Ce2O7 to Yb2Ce2O7. The effective phonon scattering by atomic weight difference contributes to the decreasing thermal conductivities from Sm2Ce2O7 to Yb2Ce2O7. These results imply that synthesized rare earth cerium oxides have potentials to be used as novel candidate materials for thermal barrier coatings in the future.

  20. Spectroscopic characteristics of Olgite (Ba,Sr)(Na,Sr){sub 2}Na[PO{sub 4}]{sub 2} crystals doped with Sm{sup 2+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Huang Yanlin [School of Material Engineering, Soochow University, 178 GanJiang East Road, Suzhou 215021 (China)], E-mail: huangyanlin@hotmail.com; Kai Weifang [School of Material Engineering, Soochow University, 178 GanJiang East Road, Suzhou 215021 (China); Lee, Ho Sueb; Cho, Eunjin [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Jang, Kiwan [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of)], E-mail: kwjang@changwon.ac.kr; Cao Yonggang; Zhao Wanxue; Ding Haiyan; Wang Xigang [School of Material Engineering, Soochow University, 178 GanJiang East Road, Suzhou 215021 (China)

    2008-10-15

    Sm{sup 3+} ions doped Olgite crystals (Ba,Sr)(Na,Sr){sub 2}Na[PO{sub 4}]{sub 2} were prepared by high temperature solid-state reaction. Sm{sup 2+} ions were obtained by X-ray irradiation reduction. The samples were investigated by X-ray diffraction, SEM, photoluminescence and decay curves measurements. In (Ba,Sr)(Na,Sr){sub 2}Na[PO{sub 4}]{sub 2}, the influence of different mole ratios of Sr to Ba atoms on the crystal structure, reducing efficiencies of Sm{sup 3+} to Sm{sup 2+} and luminescence properties of Sm{sup 2+} ions were discussed. It is found that the conversion of Sm{sup 3+} {yields} Sm{sup 2+} after X-ray irradiation is efficient in this phosphate. The emission of Sm{sup 2+} in this host after excitation into the 4f{sup 5} 5d{sup 1} levels shows {sup 5}D{sub 0} {yields} {sup 7}F{sub J} (J = 0, 1, 2) emission together with a broad emission band. The characteristic of Sm{sup 2+} ions luminescence was discussed.

  1. Spectroscopic characteristics of Olgite (Ba,Sr)(Na,Sr)2Na[PO4]2 crystals doped with Sm2+ ions

    International Nuclear Information System (INIS)

    Sm3+ ions doped Olgite crystals (Ba,Sr)(Na,Sr)2Na[PO4]2 were prepared by high temperature solid-state reaction. Sm2+ ions were obtained by X-ray irradiation reduction. The samples were investigated by X-ray diffraction, SEM, photoluminescence and decay curves measurements. In (Ba,Sr)(Na,Sr)2Na[PO4]2, the influence of different mole ratios of Sr to Ba atoms on the crystal structure, reducing efficiencies of Sm3+ to Sm2+ and luminescence properties of Sm2+ ions were discussed. It is found that the conversion of Sm3+ → Sm2+ after X-ray irradiation is efficient in this phosphate. The emission of Sm2+ in this host after excitation into the 4f5 5d1 levels shows 5D0 → 7FJ (J = 0, 1, 2) emission together with a broad emission band. The characteristic of Sm2+ ions luminescence was discussed

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

    International Nuclear Information System (INIS)

    The sorption behavior of Fe3+ , Co2+ , Ce3+ , Cs+ , and Ba2+ in aqueous solutions, was studied in presence of zeolite X. Solutions of Fe(NO3)3 . 9 H2 O, Co(NO3)2 . 6 H2 O, Ce(NO3)3 . 6 H2 O, Cs NO3 and Ba(NO3)2 were labelled with the respectively radioactive isotopes Fe59 , Co60, Cs134, Ba139 and Ce141. 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 Fe3+ 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 H3 O+ which competes with the cations for the sites in the zeolite. (Author)

  3. Redox properties and VOC oxidation activity of Cu catalysts supported on Ce{sub 1−x}Sm{sub x}O{sub δ} mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Konsolakis, Michalis, E-mail: mkonsol@science.tuc.gr [Laboratory of Physical Chemistry and Chemical Processes, Department of Sciences, Technical University of Crete, University Campus, 73100 Chania (Greece); Carabineiro, Sónia A.C., E-mail: scarabin@fe.up.pt [Laboratório de Catálise e Materiais (LCM), Laboratório Associado LSRE/LCM, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto (Portugal); Tavares, Pedro B. [CQVR, Centro de Química – Vila Real, Departamento de Química, Universidade de Trás-os-Montes e Alto Douro, 5001-911 Vila Real (Portugal); Figueiredo, José L. [Laboratório de Catálise e Materiais (LCM), Laboratório Associado LSRE/LCM, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto (Portugal)

    2013-10-15

    Highlights: • Complete elimination of ethyl acetate is achieved at 260 °C with Cu/CeO{sub 2} catalysts. • Samarium has a detrimental impact on VOC oxidation, proportional to its content. • Incorporation of Sm in ceria has a detrimental effect on textural characteristics and reducibility. • Increase of Sm/Ce ratio results in a more reduced Cu species, inactive for VOC oxidation. • A correlation between VOC activity and catalysts redox properties is established. -- Abstract: A series of Cu catalysts supported on Ce{sub 1−x}Sm{sub x}O{sub δ} mixed oxides with different molar contents (x = 0, 0.25, 0.5, 0.75 and 1), was prepared by wet impregnation and evaluated for volatile organic compounds (VOC) abatement, employing ethyl acetate as model molecule. An extensive characterization study was undertaken in order to correlate the morphological, structural and surface properties of catalysts with their oxidation activity. The optimum performance was obtained with Cu/CeO{sub 2} catalyst, which offers complete conversion of ethyl acetate into CO{sub 2} at temperatures as low as 260 °C. The catalytic performance of Cu/Ce{sub 1−x}Sm{sub x}O{sub δ} was interpreted on the basis of characterization studies, showing that incorporation of samarium in ceria has a detrimental effect on the textural characteristics and reducibility of catalysts. Moreover, high Sm/Ce atomic ratios (from 1 to 3) resulted in a more reduced copper species, compared to CeO{sub 2}-rich supports, suggesting the inability of these species to take part in the redox mechanism of VOC abatement. Sm/Ce surface atomic ratios are always much higher than the nominal ratios indicating an impoverishment of catalyst surface in cerium oxide, which is detrimental for VOC activity.

  4. High power density cell using nanostructured Sr-doped SmCoO3 and Sm-doped CeO2 composite powder synthesized by spray pyrolysis

    Science.gov (United States)

    Shimada, Hiroyuki; Yamaguchi, Toshiaki; Suzuki, Toshio; Sumi, Hirofumi; Hamamoto, Koichi; Fujishiro, Yoshinobu

    2016-01-01

    High power density solid oxide electrochemical cells were developed using nanostructure-controlled composite powder consisting of Sr-doped SmCoO3 (SSC) and Sm-doped CeO2 (SDC) for electrode material. The SSC-SDC nano-composite powder, which was synthesized by spray pyrolysis, had a narrow particle size distribution (D10, D50, and D90 of 0.59, 0.71, and 0.94 μm, respectively), and individual particles were spherical, composing of nano-size SSC and SDC fragments (approximately 10-15 nm). The application of the powder to a cathode for an anode-supported solid oxide fuel cell (SOFC) realized extremely fine cathode microstructure and excellent cell performance. The anode-supported SOFC with the SSC-SDC cathode achieved maximum power density of 3.65, 2.44, 1.43, and 0.76 W cm-2 at 800, 750, 700, and 650 °C, respectively, using humidified H2 as fuel and air as oxidant. This result could be explained by the extended electrochemically active region in the cathode induced by controlling the structure of the starting powder at the nano-order level.

  5. Synthesis and spectral analysis of Sm:BaB4O7 microfibers embedded in borate glass

    International Nuclear Information System (INIS)

    The present article reports synthesis and spectroscopic analysis of Sm:BaB4O7 microfibers embedded in borate glass. Structural analysis, using TEM, XRD techniques, revealed the formation of fibre shaped BaB4O7 crystals. A bright red dominated orange–red emission was observed, on 355 nm and 532 nm excitations, in ceramic sample. Higher emission and absorption higher cross-sections were observed in the ceramic sample than its glass counterpart. We have monitored 45% enhancement in emission intensity ratio (4G5/2→6H9/2/G5/2→6H5/2) in glass–ceramic sample due to significant increment in electric dipole transition. Time resolved analysis explored a significant alteration in the excited state relaxation process due to annealing. Several radiative parameters like stimulated emission cross-section, branching ratio, quantum efficiency etc. were estimated to explore lasing possibility in glass and ceramic samples. We found that the quantum efficiency increases from 60.4% in glass to 62.7% in Sm:BaB4O7 microfibers embedded in glass. - Highlights: • Synthesis of fibre shaped surface crystallized Sm:BaB4O7 reported in borate glass. • Strong red PL reported at various physical conditions on 532 and 355 nm excitations. • Effect of fibre growth on absorption, PL, decay dynamics was investigated. • J–O model used to calculate branching ratio, radiative lifetime, quantum efficiency. • Stimulated emission cross-section, bandwidth, gain enhances several times in fibres

  6. Mixed Conduction in BaCe08Pr0.2O3- α Ceramic

    Institute of Scientific and Technical Information of China (English)

    Mao-yuan Wang; Li-gan Qiu

    2008-01-01

    BaCe0.8Pr0.2O3-α ceramic was synthesized by high temperature solid-state reaction. The structural char- acteristics and the phase purity of the crystal were determined using powder X-ray diffraction analysis. By using the methods of AC impedance spectroscopy, gas concentration cell and electrochemical pumping of hydrogen, the conductivity and ionic transport number of BaCe0.8Pr0.2O3-α were measured, and the elec- trical conduction behavior of the material was investigated in different gases in the temperature range of 500-900 ℃. The results indicate that the material was of a single perovskite-type orthorhombic phase. Prom 500 ℃ to 900 ℃, electronic-hole conduction was dominant in dry and wet oxygen, air or nitrogen, and the total conductivity of the material increased slightly with increasing oxygen partial pressure in the oxygen partial pressure range studied. Ionic conduction was dominant in wet hydrogen, and the total conductivity was about one or two orders of magnitude higher than that in hydrogen-free atmosphere (oxygen, air or nitrogen).

  7. Ionic Conduction in Ba0.95Ce0.8Ho0.2O3-α

    Institute of Scientific and Technical Information of China (English)

    WANG,Mao-Yuan; QIU,Li-Gan; MA,Gui-Lin

    2007-01-01

    Ba0.95Ce0.8Ho0.2O3-α was prepared by high temperature solid-state reaction. X-ray diffraction (XRD) pattern showed that the material was of a single perovskite-type orthorhombic phase. Using the material as solid electrolyte and porous platinum as electrodes, the measurements of ionic transport number and conductivity of Ba0.95Ce0.8Ho0.2O3-α were performed by gas concentration cell and ac impedance spectroscopy methods in the temperature range of 600-1000 ℃ in wet hydrogen, dry and wet air respectively. Ionic conduction of the material was investigated and compared with that of BaCe0.8Ho0.2O3-α. The results indicated that Ba0.95Ce0.8Ho0.2O3-α was a pure protonic conductor with the protonic transport number of 1 during 600-700 ℃ in wet hydrogen, a mixed conductor of protons and electrons with the protonic transport number of 0.97-0.93 in 800-1000 ℃. But BaCe0.8Ho0.2O3-α was almost a pure protonic conductor with the protonic transport number of 1 in 600-900 ℃ and 0.99 at 1000 ℃ in wet hydrogen. In dry air and in the temperature range of 600-1000 ℃, they were both mixed conductors of oxide ions and electronic holes, and the oxide-ionic transport numbers were 0.24-0.33 and 0.17-0.30 respectively. In wet air and in the temperature range of 600-1000 ℃, they were both mixed conductors of protons, oxide ions and electronic holes, the protonic transport numbers were 0.11-0.00 and 0.09-0.01 respectively, and the oxide-ionic transport numbers were 0.41-0.33 and 0.27-0.30 respectively. Protonic conductivity of Ba0.95Ce0.8Ho0.2O3-α in both wet hydrogen and wet air was higher than that of BaCe0.8Ho0.2O3-α in 600-800 ℃, but lower in 900-1000 ℃. Oxide-ionic conductivity of the material was higher than that of BaCe0.8Ho0.2O3-α in both dry air and wet air in 600-1000 ℃.

  8. Enhanced stability of Zr-doped Ba(CeTb)O(3-δ)-Ni cermet membrane for hydrogen separation.

    Science.gov (United States)

    Wei, Yanying; Xue, Jian; Fang, Wei; Chen, Yan; Wang, Haihui; Caro, Jürgen

    2015-07-25

    A mixed protonic and electronic conductor material BaCe(0.85)Tb(0.05)Zr(0.1)O(3-δ) (BCTZ) is prepared and a Ni-BCTZ cermet membrane is synthesized for hydrogen separation. Stable hydrogen permeation fluxes can be obtained for over 100 h through the Ni-BCTZ membrane in both dry and humid conditions, which exhibits an excellent stability compared with Ni-BaCe(0.95)Tb(0.05)O(3-δ) membrane due to the Zr doping. PMID:26097915

  9. Spectroscopic properties of rare-earth (Eu{sup 3+}, Sm{sup 3+}) doped BaWO{sub 4} powders

    Energy Technology Data Exchange (ETDEWEB)

    Bouzidi, C., E-mail: bouzidtc@yahoo.fr [Laboratoire de Physico-chimie des Matériaux Minéraux et leurs Applications, Centre National des Recherches en Sciences des Matériaux, BP No.73, 8027 Soliman (Tunisia); Ferhi, M. [Laboratoire de Physico-chimie des Matériaux Minéraux et leurs Applications, Centre National des Recherches en Sciences des Matériaux, BP No.73, 8027 Soliman (Tunisia); Elhouichet, H. [Laboratoire de Physico-chimie des Matériaux Minéraux et leurs Applications, Centre National des Recherches en Sciences des Matériaux, BP No.73, 8027 Soliman (Tunisia); Département de Physique, Faculté des Sciences de Tunis, Université de Tunis-ElManar, ElManar 2092, Tunis (Tunisia); Ferid, M. [Laboratoire de Physico-chimie des Matériaux Minéraux et leurs Applications, Centre National des Recherches en Sciences des Matériaux, BP No.73, 8027 Soliman (Tunisia)

    2015-05-15

    BaWO{sub 4} powders doped with rare-earth ions (RE=Eu, Sm) have been prepared by the solid state reaction method at 1100 °C. The structural and optical properties have been investigated by XRD and photoluminescence (PL) measurements, respectively. The results revealed that BaWO{sub 4} powders crystallize in the tetragonal structure and exhibit a good crystallinity. Based on emission spectra, the Judd–Ofelt parameters Ω{sub 2}, Ω{sub 4} of (Eu, Sm) doped BaWO{sub 4} have been calculated. The Ω{sub 2} and Ω{sub 4} parameters have been used to calculate the total transition probabilities (A{sub T}), the stimulated emission cross-sections (σ{sub e}), the fluorescence branching ratio (β{sub R}) and radiative lifetimes (τ{sub R}) of the {sup 5}D{sub 0} level. The measured lifetimes (τ{sub mes}) were compared to the calculated (τ{sub R}) using the J–O method. The energy transfer has been investigated from the excitation spectra. The results show a broadening of the excitation bands at 396 and 465 nm of BaWO{sub 4} codoped Sm{sup 3+} and Eu{sup 3+} compared to BaWO{sub 4} doped Eu{sup 3+}. The photoluminescence (PL) intensity, the luminescence decay and the quantum efficiency (η) of {sup 5}D{sub 0}→{sup 7}F{sub 2} transition increase after adding Sm{sup 3+}. It is found that Sm{sup 3+} ion acts as sensitizer for Eu{sup 3+} ion and contributes largely to the improvement of the spectroscopic properties of BaWO{sub 4}:Eu{sup 3+}. We show that excitation transfer can occur from Sm{sup 3+} to Eu{sup 3+}. Compared to reported materials, the radiative properties obtained for {sup 5}D{sub 0}→{sup 7}F{sub 2} transition (616 nm) indicate that the present sample is promising host material for Eu{sup 3+} doped fiber amplifiers. - Highlights: • Eu{sup 3+} or/and Sm{sup 3+}:BaWO{sub 4} were prepared by the solid state reaction method. • Spectroscopic properties of BaWO{sub 4}:Eu{sup 3+} were improved by adding Sm{sup 3+}. • The energy transfer process between Eu

  10. Structural, dielectric and electrical properties of CaBa4SmTi3Nb7O30 ferroelectric ceramic

    Indian Academy of Sciences (India)

    Prasun Ganguly; A K Jha

    2011-07-01

    The polycrystalline sample of CaBa4SmTi3Nb7O30, a member of tungsten bronze family, was prepared by solid-state reaction method. X-ray diffraction analysis shows the formation of single-phase compound with an orthorhombic structure at room temperature. Scanning electron micrograph of the material shows uniform distribution of grains. Detailed studies of dielectric properties of the compound as a function of temperature at different frequencies suggest that the compound has a dielectric anomaly of ferroelectric to paraelectric type at 198°C, and exhibits non-relaxor kind of diffuse phase transition. The ferroelectric nature of the compound has been confirmed by recording polarization–electric field hysteresis loop. Piezoelectric and pyroelectric studies of the compound have been discussed in this paper. Electrical properties of the material have been analyzed using complex impedance technique. The Nyquist plots manifest the contribution of grain boundaries (at higher temperature), in addition to granular contribution (at all temperatures) to the overall impedance. The temperature dependence of dc conductivity suggests that the compound has negative temperature coefficient of resistance (NTCR) behaviour. The frequency dependence of ac conductivity is found to obey Jonscher’s universal power law. The observed properties have been compared with calcium free Ba5SmTi3Nb7O30 compound.

  11. Structure and fluorescent properties of Ba3Sc(PO4)3:Sm3+ red-orange phosphor for n-UV w-LEDs

    Science.gov (United States)

    Ma, Xiaoxue; Mei, Lefu; Liu, Haikun; Liao, Libing; Liu, Yuqin; Nie, Kun; Li, Zhaohui

    2016-06-01

    An appropriate solid-state route was adopted to synthesize a series of related Ba3Sc(PO4)3:xSm3+ red-orange phosphors. The Rietveld method was used to explore the structure of the phosphor. At present the PL, PLE, diffuse reflection and decay curves have been investigated in detail. These phosphors can be accurately excited by the 406 nm n-UV light and produce the emitted red-orange light whose peaks locate at about 566 nm, 603 nm and 650 nm. The quantum efficiency of Ba3Sc0.95(PO4)3:0.05Sm3+ was 53.5%. All above results indicate that Ba3Sc(PO4)3:Sm3+ phosphor can act as a suitable candidate of the warm components of n-UV w-LEDs.

  12. Calibration of LiBaF sub 3 Ce scintillator for fission spectrum neutrons

    CERN Document Server

    Reeder, P L

    2002-01-01

    The scintillator LiBaF sub 3 doped with small amounts of Ce sup + sup 3 has the ability to distinguish heavy charged particles (p, d, t, or alpha) from beta and/or gamma radiation based on the presence or absence of nanosecond components in the scintillation light output. Since the neutron capture reaction on sup 6 Li produces recoil alphas and tritons, this scintillator also discriminates between neutron induced events and beta or gamma interactions. An experimental technique using a time-tagged sup 2 sup 5 sup 2 Cf source has been used to measure the efficiency of this scintillator for neutron capture, the calibration of neutron capture pulse height, and the pulse height resolution--all as a function of incident neutron energy.

  13. Phase conjugator with two coherent beams in a BaTiO3: Ce crystal

    Institute of Scientific and Technical Information of China (English)

    武建劳; 谢平; 戴建华; 张洪钧

    2000-01-01

    A phase conjugator which includes two coherent beams that are incident upon one of a-faces of a BaTiO3: Ce crystal without internal reflection is performed experimentally. Based on the four-wave mixing, the mechanism of this conjugator is investigated numerically. in comparison with the cor-responding self-pumped phase conjugator, the phase-conjugate behavior of this conjugator is estab-lished much more quickly, its phase conjugate reflectivity is greater in some cases and the intensity threshold is lower by over two orders of magnitude. The configuration of this conjugator is easy to per-form because the output response exists over a wide range of angular and lateral positions of the two incident beams on the crystal.

  14. Structure and magnetic properties of Ba{sub 5}Ce{sub 1.25}Mn{sub 3.75}O{sub 15}, a new 10H-polytype in the Ba-Ce-Mn-O system

    Energy Technology Data Exchange (ETDEWEB)

    Macias, Mario A. [Grupo de Investigacion en Quimica Estructural (GIQUE), Universidad Industrial de Santander, A.A. 678, Carrera 27, Calle 9, Ciudad Universitaria, Bucaramanga (Colombia); Mentre, Olivier [Universite Lille Nord de France, Unite de Catalyse et de Chimie du Solide, Equipe Chimie du Solide, Avenue Dimitri Mendeleieev, Batiment C7, ENSCL/UST Lille 1, BP 90108, 59652 Villeneuve d' Ascq Cedex (France); Colis, Silviu [Institut de Physique et Chimie des Materiaux de Strasbourg (IPCMS), UMR 7504 UDS-CNRS (UDS-ECPM), 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France); Cuello, Gabriel J. [Institut Laue Langevin, 6 rue Jules Horowitz BP 156, F-38042 Grenoble cedex 9 (France); Gauthier, Gilles H., E-mail: gilgau@uis.edu.co [Grupo de Investigacion en Quimica Estructural (GIQUE), Universidad Industrial de Santander, A.A. 678, Carrera 27, Calle 9, Ciudad Universitaria, Bucaramanga (Colombia); CEA, LITEN, Laboratoire d' Innovation Technologique et des Energies Nouvelles, 17 rue des Martyrs, 38054 Grenoble (France)

    2013-02-15

    Based on the peculiar magnetic properties that are observed in pseudo one-dimensional manganites, we decided to synthesize the new Ba{sub 5}Ce{sub 1.25}Mn{sub 3.75}O{sub 15} compound. The preparation was performed by solid state reaction in air at about 1350 Degree-Sign C, for which we found that the compound crystallizes in a hexagonal symmetry with space group P6{sub 3}/mmc (No-194) and cell parameters a=b=5.7861(2) A and c=23.902(1) A. The structural description was correlated with neutron diffraction and bond valence calculations, confirming the presence of Ce{sup 4+} and Mn{sup 4+} segregated in the different crystallographic positions. Ba{sub 5}Ce{sub 1.25}Mn{sub 3.75}O{sub 15} displays evidence for strong AFM couplings already set at room temperature. The main arrangement of Mn{sup 4+} in magnetically isolated tetramers of face-sharing octahedra is responsible for a metamagnetic-like transition around 50 K. - Graphical abstract: The new Ba{sub 5}Ce{sub 1.25}Mn{sub 3.75}O{sub 15} polytype shows strong AFM couplings in magnetically isolated [Ce{sub 0.25}Mn{sub 3.75}O{sub 15}] tetramers of face-sharing octahedral, resulting in a metamagnetic-like transition around 50 K. Highlights: Black-Right-Pointing-Pointer Ba{sub 5}Ce{sub 1.25}Mn{sub 3.75}O{sub 15}, a new 10H polytype, has been prepared in the Ba-Ce-Mn-O system. Black-Right-Pointing-Pointer The compound crystallizes in the P6{sub 3}/mmc space group with (cchhh){sub 2} stacking sequence. Black-Right-Pointing-Pointer [Ce{sub 0.25}Mn{sub 3.75}O{sub 15}] tetramers are separated by [CeO{sub 6}] octahedra in the structure. Black-Right-Pointing-Pointer Instead of robust AFM ordering, a metamagnetic-like transition is found around 50 K.

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

  16. Ionic conduction in Ba_xCe_(0.8)Pr_(0.2)O_(3-α)

    Institute of Scientific and Technical Information of China (English)

    WANG Maoyuan; QIU Ligan; SUN Yufeng

    2009-01-01

    Ba_xCe_(0.8)Pr_(0.2)O_(3-α)(X=0.98-1.03) ceramics were prepared by high temperature solid-state reaction. X-ray diffraction (XRD) patterns showed that the materials were perovskite-type orthorhombic single phase. By using gas concentration cell and AC impedance spectroscopy methods, the electrical conduction behavior of the materials was investigated in different gases at 500-900 ℃. The influence of non-stoichiometry in the materials with x≠1 on conduction properties was studied and compared with that in the material with x=1. The results indicated that Ba_(1.03)Ce_(0.8)Pr_(0.2)O_(3-α) was a pure protonic conductor, and Ba_(0.98)Ce_(0.8)Pr_(0.2)O_(3-α) was a mixed conductor of protons and electrons in wet hydrogen at 500-900 ℃. BaCe_(0.8)Pr_(0.2)O_(3-α) was a pure protonic conductor in 500-600 ℃, and a mixed conductor of protons and electrons above 600℃ in wet hydrogen. In 500-900℃, they were all mixed conductors of oxide ions and electronic holes in dry air, and mixed con-ductors of protons, oxide ions and electronic holes in wet air. Both the protonic and oxide ionic conductivities increased with increasing bar-ium content in the materials in wet hydrogen, dry air and wet air, respectively.

  17. Synthesis and thermochemistry of new phase BaCe0.7Nd0.2In0.1O2.85

    International Nuclear Information System (INIS)

    Highlights: •We synthesized new phase BaCe0.7Nd0.2In0.1O2.85. •We measured formation enthalpy of BaCe0.7Nd0.2In0.1O2.85. •The phase is thermodynamically stable with respect to decomposition into binary oxides. -- Abstract: The BaCe0.7Nd0.2In0.1O2.85 phase has been prepared from BaCO3, CeO2, Nd2O3 and In2O3. X-ray measurements have showed that BaCe0.7Nd0.2In0.1O2.85 has an orthorhombic structure (Pmcn space group). The standard formation enthalpy of BaCe0.7Nd0.2In0.1O2.85 has been determined by solution calorimetry combining solution enthalpies of BaCe0.7Nd0.2In0.1O2.85, BaCl2 + 0.7CeCl3 + 0.2NdCl3 + 0.1InCl3 mixture in 1 M HCl with KI and literature data. We determined the thermodynamic stability of Nd(In)-doped barium cerate with respect to mixtures of binary oxides. On the basis of the data we established that above-mentioned mixed oxide is thermodynamically stable with respect to their decomposition into binary oxides at room temperatures. We also established that BaCe0.7Nd0.2In0.1O2.85 is thermodynamically favored than BaCe0.8Nd0.2O2.9

  18. Effects of NiO on the conductivity of Ce0.85Sm0.15O1.925 and on electrochemical properties of the cathode/electrolyte interface

    Science.gov (United States)

    Wang, Haopeng; Liu, Xiaomei; Bi, Hailin; Yu, Shenglong; Han, Fei; Sun, Jialing; Zhu, Lili; Yu, Huamin; Pei, Li

    2016-07-01

    Ce0.85Sm0.15O1.925 (SDC) and Ce0.85Sm0.15O1.925-0.5 at.% NiO (SDCN) are investigated as electrolytes for solid oxide fuel cells (SOFCs). Impedance spectroscopy measurements reveal that the grain boundary resistance can be significantly reduced by adding 0.5 at.% NiO to SDC. Symmetric cells of the BaCo0.7Fe0.2Nb0.1O3-δ (BCFN) electrode on SDC and SDCN electrolytes are fabricated and the electrochemical properties of the electrode/electrolyte interface are investigated. The polarization resistance of the BCFN electrode on the SDCN electrolyte is much lower than that of the BCFN electrode on the SDC electrolyte, mainly because of the increase in the electrolyte conductivity and the decrease in the Si content at the electrode/electrolyte interface. NiO is able to restrict the diffusion of the siliceous impurity from the electrolyte to the electrode/electrolyte interface. Single cells based on SDC and SDCN electrolytes are fabricated using Ni0.9Cu0.1Ox-SDC as the anode and BCFN as the cathode. At 800 °C, the maximum power density of the SDCN-based cell is 0.745 W cm-2, which is much higher than that of the SDC-based cell.

  19. Crystallographic Study of Mixture CeBa1.8Pb0.2Cu3Oy in the Range of 860 deg. C to 940 deg. C

    International Nuclear Information System (INIS)

    A powder mixture with chemical formula CeBa1.8Pb0.2Cu3Oy was prepared. The mixture was heated in free atmosphere, at temperatures 860 deg. C to 940 deg. C, for 24 to 72h. The samples were measured by X-Ray powder diffraction with CuKa radiation. Each sample was characterized with the help of the PDF and refined, using the Rietveld's ''Powder Profile Analysis''. The first sample (860 deg. C) was identified with the phases: Ba2CeBiO6, CuO and BaCuO2, while all the remaining samples (870 deg. C-940 deg. C) with the phases Ba2CePbO6, CuO and CeO2. The phases Ba2CeBiO6 and Ba2CePbO6 are the main phases with analogous chemical types, but different symmetry. The phase CuO is common in all the samples, while from the remaining phases the BaCuO2 appears only in the first sample and the CeO2 in all, except the first one. The quantity 0.2 of Pb is distributed in the Ba positions, substituting a part of these. The percentages of phases are about 82%, 10% and 8% for the first sample and for all the remaining about 85%, 8% and 7%, respectively with above serious

  20. Protonic Conduction of BaCe0.85YO. 1503 Doped with SrTiO3

    Science.gov (United States)

    Dynys, Frederick W.; Sayir, Ali

    2005-01-01

    Reformers based on ceramic membrane technology potentially offer hydrogen production that is comparable to the cost of fossil fuels. Protonic conducting ceramic with the chemical formula AB03 offers the promise of highly selective hydrogen separation at intermediate temperature (400-800 C). Among different perovskite-type oxides, BaCe03 and SrCe03 based compositions show high protonic conductivities but strong resistance to densification. X-ray diffraction studies on sintered specimens of BaCe0.85Y0.1503-6 show multi-phase formation which was found to show dependence upon powder synthesis method. Doping with SrTiO3 suppresses multi-phase formation and enhances grain growth. Conductivity measurements in temperature range of 200 to 1000 C were performed by ac impedance spectroscopy under dry and wet conditions. Sintering behavior, phase formation and conductivity results will be reported.

  1. Probing the (p,T) phase diagram of CeFe2 and SmS using resonant x-ray scattering

    International Nuclear Information System (INIS)

    Two strongly correlated electron systems CeFe2 and SmS have been studied using x-ray magnetic resonant scattering at low temperatures and high pressures. First, the magnetic ground state of CeFe2 doped with 7% Co has been probed by means of resonant x-ray magnetic scattering across the temperature range 10-95 K at pressures up to 9.5 kbar. A strong increase of the Neel temperature with pressure has been evidenced. Furthermore, a large increase in scattering intensity is observed just before TN at 9.5 k-bar. These results reveal that the itinerant character of the 4f electrons which stabilize the antiferromagnetic state has been probed. Secondly, the structural and electronic properties of SmS have been studied under pressure up to 29 k-bar and at temperatures down to 4.5 K via absorption and diffraction techniques. The measurements are a direct probe of the valence of Sm in SmS at low temperature from the black insulator phase to the gold metallic phase and furthermore across the magnetic transition. In particular, it is found that Sm in SmS has an intermediate valence (2.81(4)) in the magnetically ordered phase at 29 kbar and 4.5 K

  2. Photoluminescence properties of M{sub 2}Mg(BO{sub 3}){sub 2}:Sm{sup 3+} (M:Sr and Ba)

    Energy Technology Data Exchange (ETDEWEB)

    PEKGOeZLUe, Ilhan, E-mail: pekgozluilhan@yahoo.com [Bartin University, Faculty of Engineering, Department of Environmental Engineering, Bartin 74100 (Turkey)

    2013-02-15

    M{sub 2}Mg(BO{sub 3}){sub 2}:Sm{sup 3+} (M:Sr and Ba) phosphors were synthesized by a solution combustion synthesis method followed by heating of the precursor combustion ash at 900 Degree-Sign C in air. The synthesized materials were characterized by using the powder XRD. The emission and excitation spectra of these materials were measured at room temperature with a spectrofluorometer. Both Sr{sub 2}Mg(BO{sub 3}){sub 2}:Sm{sup 3+} and Ba{sub 2}Mg(BO{sub 3}){sub 2}:Sm{sup 3+} phosphors emit a strong in orange-red region. It was observed that the optimum concentration of Sm{sup 3+} in Sr{sub 2}Mg(BO{sub 3}){sub 2} and Ba{sub 2}Mg(BO{sub 3}){sub 2} are 0.01 and 0.04 mol, respectively. Finally, the relation between the photoluminescence properties of Sm{sup 3+} and host compositions was discussed in detail. - Highlights: Black-Right-Pointing-Pointer It has synthesized two novel inorganic borate phosphors for the first time. Black-Right-Pointing-Pointer The synthesized materials were characterized by using the powder X Ray Diffraction. Black-Right-Pointing-Pointer The photoluminescence properties of both phosphors were investigated using a spectrofluorometer. Black-Right-Pointing-Pointer Both Sr{sub 2}Mg(BO{sub 3}){sub 2}: Sm{sup 3+} and Ba{sub 2}Mg(BO{sub 3}){sub 2}: Sm{sup 3+} phosphors emit a strong in orange-red region.

  3. Magnetization and heat capacity studies of double perovskite compounds Ba{sub 2}SmRuO{sub 6} and Ba{sub 2}DyRuO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rakesh, E-mail: rakesh.kumar@impmc.jussieu.f [Indian Institute of Technology, Bombay, Mumbai 400 076 (India); Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 (India); Tomy, C.V. [Indian Institute of Technology, Bombay, Mumbai 400 076 (India); Nagarajan, R. [University of Mumbai, Department of Atomic Energy, Center for Excellence in Basic Sciences, University of Mumbai Campus, Vidyanagari, Mumbai 400 016 (India); Paulose, P.L. [Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 (India); Malik, S.K. [International Center for Condensed Matter Physics, Universidade de Brasilia, Campus Universitario Darcy Ribeiro, 70919-970 Brasilia-DF (Brazil)

    2009-08-01

    Here we report the magnetic and heat capacity studies of the double perovskite compounds Ba{sub 2}SmRuO{sub 6} and Ba{sub 2}DyRuO{sub 6}. Antiferromagnetic transitions are inferred at 54 and 47 K in Ba{sub 2}SmRuO{sub 6} and Ba{sub 2}DyRuO{sub 6}, respectively, in the magnetization measurements. Heat capacity measurements show large jumps at the corresponding temperatures and confirm the bulk magnetic ordering. Both the measurements provide clear indication of the ordering of the rare earth moments also along with the Ruthenium moments. However, the heat capacity results suggest that the ordering of rare earth magnetic moments is spread over a large temperature range. An anomaly observed in the magnetization measurements at 42 K (below the magnetic ordering) in Ba{sub 2}SmRuO{sub 6} is discerned as a reorientation of Sm{sup 3+} moments.

  4. Energy levels in YPO{sub 4}:Ce{sup 3+},Sm{sup 3+} studied by thermally and optically stimulated luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Bos, Adrie J.J., E-mail: a.j.j.bos@tudelft.n [Delft University of Technology, Mekelweg 15, NL 2629 JB Delft (Netherlands); Poolton, Nigel R.J. [Delft University of Technology, Mekelweg 15, NL 2629 JB Delft (Netherlands); Institute of Maths and Physics, Aberystwyth University, Aberystwyth SY23 3BZ (United Kingdom); Wallinga, Jakob [Netherlands Centre for Luminescence Dating, Delft University of Technology, Mekelweg 15, NL 2629 JB Delft (Netherlands); Bessiere, Aurelie [Ecole Nat. Superieure de Chimie de Paris, 11 Rue P et M Curie, 75231 Paris Cedex 05 (France); Dorenbos, Pieter [Delft University of Technology, Mekelweg 15, NL 2629 JB Delft (Netherlands)

    2010-03-15

    Energy-resolved optically stimulated luminescence (OSL) spectra and thermoluminescence (TL) glow curves of a powder sample of YPO{sub 4}:Ce{sup 3+},Sm{sup 3+} were measured to investigate the nature of the trapping centre and to locate its energy level relative to the valence and conduction bands of the YPO{sub 4} host. The high-temperature glow peak could unequivocally be assigned to Sm{sup 2+} (thus Sm{sup 3+} acts as an electron trap). The trap depth of this centre, as derived from the OSL excitation spectra, is in good agreement with the Dorenbos model prediction. The OSL excitation spectra also reveal excited states of Sm{sup 2+} well below the conduction band. These excited states produce a broadening of the high-temperature TL glow peak and also cause the activation energy determined by the Hoogenstraten method to underestimate the trap depth.

  5. Effect of pressure on the free ion and crystal field parameters of Sm2+ in BaFBr and SrFBr hosts

    International Nuclear Information System (INIS)

    The emission spectra of Sm2+ doped in BaFBr and SrFBr hosts were measured at 10 K from ambient pressure to 8 GPa. The crystal field energy levels determined from the emission spectra were used to extract the free ion parameters (Fk and ζ) and crystal field parameters (Bqk). The variation of Fk and ζ as a function of pressure was studied systematically and was discussed in relation to the central field and symmetry restricted covalency models. The change of the spin–orbit coupling parameter (ζ) with pressure for SrFBr:Sm2+ showed very different behavior than in other matlockite hosts. Moreover the variation of Bqk under pressure was studied. The pressure dependence of the Bqk was described quantitatively using the Superposition Model (SM) with the help of structural parameters as a function of pressure, obtained from periodic DFT calculations. The validity of the SM was tested for Sm2+ in BaFBr and SrFBr. It is shown that this model does not apply to SrFBr, in contrast to other matlockite host materials. - Highlights: ► Luminescence at 10 K from ambient pressure to 8 GPa were measured for BaFBr:Sm2+ and SrFBr:Sm2+. ► The free ion (F2 and ζ) and crystal field parameters were determined as a function of pressure. ► Crystal field strength shows different trend for the two compounds. ► The superposition model is unable to explain the unusual behavior of intrinsic parameters in SrFBr:Sm2+.

  6. Structure and properties of rhombohedral CePd3Ga8: A variant of the cubic parent compound with BaHg11 structure type

    International Nuclear Information System (INIS)

    Single crystals of a new intermetallic gallide, R-CePd3Ga8, have been synthesized from excess molten gallium. Single-crystal X-ray diffraction reveals that R-CePd3Ga8 crystallizes in the R-3m space group with a=b=c=8.4903(10) Å and α=β=γ=89.993(17). R-CePd3Ga8 is a variant of the cubic BaHg11 structure type with three structural units: a Ce-centered polyhedron, a distorted cube of Pd2Ga6 and a Pd-centered cuboctahedron. The distortions of these units are compared to undistorted analogous units in intermetallic compounds with BaHg11 structure type. Field and temperature-dependent magnetization measurements on R-CePd3Ga8 reveal a paramagnetic material with strong antiferromagnetic correlations and a magnetization consistent with Ce3+. Electrical resistance measurements indicate Kondo behavior between localized Ce3+ magnetic moments. - Graphical Abstract: Single crystals of CePd3Ga8 have been synthesized from Ga flux. This new compound is the first rhombohedral variant of the cubic BaHg11 structure type. Highlights: ▶ Single crystals of CePd3Ga8 were synthesized from gallium flux. ▶ CePd3Ga8 is the first rhombohedral variant of the cubic BaHg11 structure type. ▶ Paramagnetic with antiferromagnetic correlations. ▶ Magnetization consistent with Ce3+.

  7. Sm2NiSn4: The intermediate structure type between ZrSi2 and CeNiSi2

    International Nuclear Information System (INIS)

    A new rare earth nickel stannide, Sm2NiSn4, has been prepared by reacting the pure elements at high temperature in welded tantalum tubes. Its crystal structure was established by single crystal X-ray diffraction studies. Sm2NiSn4 crystallizes in the orthorhombic space group Pnma (No. 62) with cell parameters of a=16.878(2) A, b=4.4490(7) A, c=8.915(1) A, and Z=4. Its structure can be viewed as the intermediate type between ZrSi2 and CeNiSi2. Sm2NiSn4 features two-dimensional (2D) corrugated [NiSn4]6- layers in which the 1D Sn zigzag chains and the 2D Sn square sheets are bridged by Ni atoms. The Sm3+ cations are located at the interlayer space. Results of both resistivity measurements and extended-Hueckel tight-binding band structure calculations indicate that Sm2NiSn4 is metallic. -- Graphical Abstract: A new rare earth nickel stannide, Sm2NiSn4, has been prepared by the solid-state reactions of the corresponding pure elements at high temperature in welded tantalum tubes. Its structure can be viewed as the intermediate type between ZrSi2 and CeNiSi2. Sm2NiSn4 features 2D corrugated [NiSn4]6- layers in which the 1D Sn zigzag chains and the 2D Sn square sheets are bridged by Ni atoms. Results of both resistivity measurements and extended-Hueckel tight-binding band structure calculations indicate that Sm2NiSn4 is metallic

  8. The effect of Gd2BaCuO5 nanoparticles on irreversibility fields of (Nd-Sm-Gd)Ba2Cu3O7-δ

    International Nuclear Information System (INIS)

    The flux pinning behaviour of (Nd1/3Sm1/3Gd1/3)Ba2Cu3O7-δ samples, having different concentrations x of Gd2BaCuO5 secondary-phase nanoparticles, was studied using magnetoresistivity data collected in the presence of 0, 0.5, 1, 2, 4, 6, 8 T magnetic fields (H) along and perpendicular to the c axis, with the transport current lying in the ab plane. Significant enhancement of the flux pinning and hence also the irreversibility field Hirr(T) was found. Hirr(T) extrapolated to 77K, Hirr77K(T), was determined from the Hirr(T) plots using best fits to an empirical formula, Hirr(T) Hirr(0)(1- T/Tc)a, where a is a constant. Hirr77K(T) for H parallel c axis (a) remains almost constant up to x = 0.2 (b) increases beyond x = 0.2 (c) peaks at x = 0.4 and (d) falls beyond x = 0.4. Further, Hirr77K(T) values are above 15T, the maximum being 243T for the 40wt% sample

  9. Synthesis, vacuum ultraviolet and ultraviolet spectroscopy of Ce3+ ion doped olgite Na(Sr, Ba)PO4

    International Nuclear Information System (INIS)

    Ce3+ ion doped olgite mineral samples, Na(Sr, Ba)PO4, were prepared by a high temperature solid-state reaction. The sample was investigated through x-ray powder diffraction, FT-IR and FT-Raman spectra measurements. The optical properties under vacuum ultraviolet (VUV) synchrotron radiation and ultraviolet (UV) irradiation are reported for the first time. The investigated samples show a strong absorption in the VUV and UV ranges. The bands corresponding to the 4f1 → 4f05d1 transitions of Ce3+ ions in the host lattices are identified. The barycentre of Ce3+ ions in the host lattices, the host absorption, the crystal field splitting, the emission and the Stokes shifts are presented and discussed. This Ce3+ ion doped material is a potential candidate for plasma display panel (PDP) application

  10. NUTRIENT ALLOCATION IN Eucalyptus saligna Sm. STANDS IN THE REGION OF GUAÍBA - RIO GRANDE DO SUL

    Directory of Open Access Journals (Sweden)

    Rudi Witschoreck

    2015-12-01

    Full Text Available This research conducted in Eucalyptus saligna Sm. stands, between 2 and 7 years of age, in the region of Guaíba - RS, had as objective: to estimate the nutrients stock in the biomass. On the basis of the forest inventory, trees of medium diameter were collected and fractionated in leaf, branch, bark, wood and root. The accumulated litter was evaluated with sampling units of 1 m2. Samples of arboreal components and litter were collected to estimate the dry matter and nutritional content. Nutrients stock was obtained through the product between the average biomass of each component and the average concentration of nutrients. For the average of stands, the stock of nutrients showed the following order of accumulation, for biomass components: wood > root > leaf > bark > branch; and for nutrients: Ca > N > K > Mg > P.

  11. Quantitative description of the phase transition of Aurivillius oxides Sm modified BaBi4Ti4O15 ceramics

    International Nuclear Information System (INIS)

    BaBi4Ti4O15+xwt.%Sm2O3 (x=0.00, 0.25, 0.50, 0.75) ceramics were prepared by the solid-state reaction method. The effect of samarium additives on the structural and electrical properties of BBT ceramic was investigated. XRD patterns indicate that all ceramics are an m=4 members of Aurivillius oxides and no secondary phases were detected. A broad dielectric peak in frequency dependent dielectric spectrum is observed during the phase transition of all the BBT ceramics. The modified Curie–Weiss law, Vogel–Fucher relationship and Lorentz-type law were used to describe the phase transition behavior. The relaxor behavior was described well by the modified Curie–Weiss law and Vogel–Fucher relation. The effect of samarium additives on the degree of relaxation and diffuseness of BBT ceramics was discussed

  12. Fabrication of catalytically active nanocrystalline samarium (Sm)-doped cerium oxide (CeO2) thin films using electron beam evaporation

    International Nuclear Information System (INIS)

    Samarium (Sm)-doped cerium oxide (CeO2) thin films were fabricated using electron beam evaporation technique. The synthesized films were deposited either on glass or ITO substrates and studied their nature by annealing at different temperatures. The optical properties and other morphological studies were done by UV–Vis, XRD, XPS, SEM, EDS, and FT-IR analysis. XRD and XPS analysis clearly confirm the presence of Sm in the ceria site. From the SEM study, it was found that after annealing at high temperature (∼300 or 500 °C), the particles size was reduced due to breakdown of large aggregates of particles which is also confirmed from UV–Vis, XPS, and XRD analyses. The FT-IR study proves the presence of –COO–, –OH, or ammonium group on the particles surface. The deposition of Sm-doped CeO2 nanomaterials was found more feasible on ITO substrate compared to that of glass substrate in terms of stability and depth of film thickness. The Sm-doped CeO2 nanomaterial acts as a re-usable catalyst for the reduction of organic dye molecules in the presence of NaBH4. The catalysis rate was compared by considering the electron transfer process during the reduction. The synthesized Sm-doped CeO2 thin films might find wide variety of applications in various emerging fields like solid oxide fuel cells (SOFCs), oxygen sensor or as catalyst in different types of organic and inorganic catalytic reactions. The fabrication process is very simple, straightforward, less time consuming, and cost effective.Graphical Abstract

  13. Synthesis, characterization and TL response of Ce3+ activated BaMgAl10O17 phosphor

    International Nuclear Information System (INIS)

    Phosphor material BaMgAl10O17 with varying concentration of rare earth Ce3+ synthesis by combustion method at 500°C. The synthesized phosphor material characterized for their crystallinity and nature by XRD measurements. The thermoluminescecne response of phosphor exhibit TL spectra at 204°c and detailed analysis of kinetic parameter by de convoluted curve. These results show that concentration quenching occur at 5mol% of Ce dopant. The results suggest the possibility of utilizing as a phosphor may be in UV dosimeter and solid state lighting

  14. Ce substitution for Gd in Gd1-xCexBa2Cu3O7-δ

    International Nuclear Information System (INIS)

    Full text: It has been found that REBa2Cu3O7-δ compounds with RE=rare earths elements, except Ce, Pr, Pm and Tb, have the same crystal structure, normal state properties, and transition temperature near 92K. RE compounds with RE=Ce and Tb due to their tendency toward tetravalence or mixed valence behavior do not form in the 123 orthorhombic structure. Moreover, both Ce and Tb form double oxides BaCeO3 and BaTbO3, respectively, which lead to formation of multiphase samples. In regards to the ionic radius, it has been demonstrated that the effective ionic radius of the trivalence element is important for the formation of 123 phase. Related to the RE radius, Nd123 has the stable structure; since Ce and Nd have approximately the same radius, the instability of Ce123 phase cannot be related to its radius. We have substituted Ce for Gd in Gd1-xCexBa2Cu3O7-δ compounds. We have prepared Gd1-xCexBa2Cu3O7-δ compounds with x=0.0, 0.03, 0.05, 0.09, 0.1, 0.12, 0.15, 0.3, 0.325, 0.35, 0.4, 0.5, 0.6 by the standard solid-state reaction technique. The resistivity has been measured under an applied magnetic field in the range 0 to 15KOe in the temperature range 10K to 300K. X-ray diffraction experiments are performed and its results are refined by the Rietveld method. X-ray diffraction analysis shows a predominantly single phase perovskite structure with few impurity phases, but in the compound with x=0.4 a pure single phase is formed. Magnetic properties are measured via a vibrating sample magnetometer at 77K in magnetic field up to 15KOe. Our resistivity results show that by increasing Ce content, Tc decreases, but the transition width increases, and in the normal state a metal-insulator transition occurs. The normal state resistivity does not change with applying the magnetic field, but the transition width changes distinctively after the branching point. In these samples, the onset transition temperature increases slowly with applying magnetic field, which is interesting and

  15. (La, Pr)0.8Sr0.2FeO3-δ-Sm 0.2Ce0.8O2-δ composite cathode for proton-conducting solid oxide fuel cells

    KAUST Repository

    Chen, Yonghong

    2014-08-01

    Mixed rare-earth (La, Pr)0.8Sr0.2FeO 3-δ-Sm0.2Ce0.8O2-δ (LPSF-SDC) composite cathode was investigated for proton-conducting solid oxide fuel cells based on protonic BaZr0.1Ce0.7Y 0.2O3-δ (BZCY) electrolyte. The powders of La 0.8-xPrxSr0.2FeO3-δ (x = 0, 0.2, 0.4, 0.6), Sm0.2Ce0.8O2-δ (SDC) and BaZr0.1Ce0.7Y0.2O3-δ (BZCY) were synthesized by a citric acid-nitrates self-propagating combustion method. The XRD results indicate that La0.8-xPrxSr 0.2FeO3-δ samples calcined at 950 °C exhibit perovskite structure and there are no interactions between LPSF0.2 and SDC at 1100 °C. The average thermal expansion coefficient (TEC) of LPSF0.2-SDC, BZCY and NiO-BZCY is 12.50 × 10-6 K-1, 13.51 × 10-6 K-1 and 13.47 × 10-6 K -1, respectively, which can provide good thermal compatibility between electrodes and electrolyte. An anode-supported single cell of NiO-BZCY|BZCY|LPSF0.2-SDC was successfully fabricated and operated from 700 °C to 550 °C with humidified hydrogen (∼3% H2O) as fuel and the static air as oxidant. A high maximum power density of 488 mW cm -2, an open-circuit potential of 0.95 V, and a low electrode polarization resistance of 0.071 Ω cm2 were achieved at 700 °C. Preliminary results demonstrate that LPSF0.2-SDC composite is a promising cathode material for proton-conducting solid oxide fuel cells. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  16. Synthesis and characterization of Ce{sub 1-x}SmXO{sub 2-(x/2)} as solid electrolyte for application in IT-SOFCs; Sintese e caracterizacao de Ce{sub 1-x}SmXO{sub 2-(x/2)} como eletrolito solido para aplicacao em IT-SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Nicodemo, J.P.; Martinelli, A.E.; Nascimento, R.M. [Universidade Federal do Rio Grande do Norte (DECM/UFRN), Natal, RN (Brazil). Dept. de Engenharia de Materiais], e-mail: juli_pivotto@yahoo.com.br; Melo, D.M.A. [Universidade Federal do Rio Grande do Norte (DQ/UFRN), Natal, RN (Brazil). Dept. de Quimica; Cela, B. [Universidade Federal do Rio Grande do Norte (PPGCEM/UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Macedo, D.A. [Universidade Federal do Rio Grande do Norte (PPGEM/UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica

    2008-07-01

    Mixed rare earth doped CeO{sub 2} oxide-based have been extensively studied for use in solid electrolytes for fuel cells. Ceramics-based CeO{sub 2} have high ionic conductivity and enable the operation of solid oxide fuel cells (SOFCs) in intermediate temperatures, in the range of 500 to 750 deg C. In this work, was investigated the Sm{sub 2}O{sub 3} doped CeO{sub 2} by Pechini method to obtain Ce{sub 0,9}Sm{sub 0,1}O{sub 1,95}. The resulting powders were characterized by the chemical composition (EDS) and crystallographic (XRD), thermal analysis (TG/ATD and DTG), and particles morphology (SEM). After calcinations of 500 and 700 deg C for 2 hours were obtained nanosized powders with crystalline structure of cubic phase type fluorite fully formed. (author)

  17. Characterization of an optically stimulated luminescence (OSL) material for thermal neutron detection: SrS:Ce,Sm,B

    Energy Technology Data Exchange (ETDEWEB)

    Ravotti, Federico [Institut d' Electronique du Sud (IES), UMR UM2-CNRS 5214, Universite Montpellier 2, Place Eugene Bataillon - CC 083, 34095 Montpellier Cedex 5 (France); CERN, Physics Department, 1211 Geneva 23 (Switzerland); Garcia, Pierre; Prevost, Hildegarde; Dusseau, Laurent [Institut d' Electronique du Sud (IES), UMR UM2-CNRS 5214, Universite Montpellier 2, Place Eugene Bataillon - CC 083, 34095 Montpellier Cedex 5 (France); Lapraz, Dominique [Laboratoire de Physique Electronique des Solides (LPES), Centre de Recherches sur les Solides et leurs Applications (CRESA), EA 1174, Faculte des Sciences, Universite de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 2 (France); Vaille, Jean-Roch [Institut d' Electronique du Sud (IES), UMR UM2-CNRS 5214, Universite Montpellier 2, Place Eugene Bataillon - CC 083, 34095 Montpellier Cedex 5 (France); Universite de Nimes, Site des Carmes, Place Gabriel Peri, 30021 Nimes Cedex 01 (France); Benoit, David

    2008-05-15

    SrS:Ce,Sm exhibits some interesting phosphorescent and charge storage properties that are used in OSL (optically stimulated luminescence) radiation dosimetry. To enhance the thermal neutron sensitivity of this phosphor, a new material obtained by boron doping has been developed. This OSL, B material was analysed with respect to its optical and structural characteristics in order to study possible modifications induced by doping procedure. Optical study highlights a decrease in the material luminescence of about 40% with TL and OSL experiments. The emission spectrum remains the same after boron addition. This result is in agreement with the structural characterization analysis since the lattice parameters were not modified. 11B MAS NMR results indicate that boron atoms are present in the host lattice in form of BO4 groups. Consequences on dosimetry applications are discussed. The neutron response of the OSL, B irradiated in a nuclear reactor is linear up to a fluence of 5 x 1011 cm{sup -2} and it is possible to separate the thermal neutron and gamma components. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Space-Selective Precipitation of Ba2TiSi2O8 Crystals in Sm3+-Doped BaO-TiO2-SiO2 Glass by Femtosecond Laser Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZHU Bin; DAI Ye; MA Hong-Liang; LIN Geng; QIU Jian-Rong

    2008-01-01

    The ferroelectric crystal Ba2TiSi2O8 with high second-order optical nonlinearity is precipitated in Sm3+-doped BaO-TiO2-SiO2 glass by a focused 800 nm,250 kHz and 150 fs femtosecond laser irradiation.No apparent blue and red emissions are observed at the beginning,while strong blue emission due to second harmonic generation and red emission due to the f-f transitions of Sm3+ are observed near the focal point of the laser beam after irradiation for 25 s. Micro-Raman spectra confirm that Ba2TiSi2O8 crystalline dots and lines are formed after laser irradiation.The mechanism of the phenomenon is discussed.

  19. Anisotropic superconducting-state thermodynamic parameters of the electron-doped compound Sm1.85Ce0.15CuO4-y

    International Nuclear Information System (INIS)

    The anisotropic superconducting-state thermodynamic parameters of the electron-doped compound Sm1.85Ce0.15CuO4-y have been derived from reversible dc magnetization M(H,T) measurements on magnetically aligned single-crystal particles of the compound for magnetic fields applied perpendicular and parallel to the ab plane. A recent model developed by Hao et al., which describes M(H,T) over the entire field region between Hc1 and Hc2, was used to analyze the M(H,T) data. The analysis of the measurements provides a self-consistent test of the model and resolves a controversy by showing that the anisotropy of Hc2(T) of the electron-doped compound Sm1.85Ce0.15CuO4-y is comparable to that of the hole-doped compound YBa2Cu3O7-δ

  20. Fabrication and Mechanical Properties of Sm2O3 Doped CeO2 Reinforced Ti3AlC2 Nano Composite

    Institute of Scientific and Technical Information of China (English)

    Jae Ho Han; Sang Whan Park; Young Do Kim

    2004-01-01

    The fabrication process of Sm2O3 doped CeO2 reinforced Ti3AlC2 nano composites including the nano particle dispersion process by a hetero-coagulation process was developed using in-situ synthesis and densification process of Ti3AlC2. The effects of Sm2O2 doped CeO2 nano particles on mechanical properties of Ti3AlC2 were investigated. It was found that the presence of 20SDC nano particles in Ti3AlC2 was very effective to improve the mechanical properties of Ti3AlC2 without spoiling the unique characteristics of Ti3AlC2temary carbide.

  1. Mobilidade de oxigênio intersticial em cerâmicas SmBa2Cu3O7-delta Mobility of interstitial oxygen in SmBa2Cu3O7-delta ceramics

    Directory of Open Access Journals (Sweden)

    R. M. Nascimento

    2005-09-01

    Full Text Available Desde a descoberta dos supercondutores com alta temperatura crítica, vários trabalhos têm sido efetuados sobre as diferentes propriedades destes materiais. As cerâmicas YBa2Cu3O7-delta mostraram que têm suas propriedades supercondutoras fortemente afetadas pela quantidade de oxigênio. Mais recentemente, medidas de relaxação anelástica em La2CuO4+delta mostraram que a remoção deste elemento pode ser relacionada com dois eventos. Um deles é o decréscimo na mobilidade entre dois planos adjacentes CuO e o outro, é o aumento no número de padrões de mobilidade para os octaedros CuO6. Para SmBa2Cu3O7 (SBCO, a possibilidade de uma estequiometria de oxigênio variável e sua alta mobilidade nos planos CuOx, dá origem a um diagrama de fases bastante rico. Neste trabalho, são reportadas medidas de espectroscopia anelástica em amostras de SBCO, que mostram um pico de relaxação termicamente ativado, que foi atribuído aos saltos de átomos de oxigênio nas posições O1 e O5 da rede.Since the discovery of the high-Tc superconductors, several works have been made about the different properties of these materials. The YBa2Cu3O7-delta ceramic showed to have its superconducting properties strongly affected by the oxygen content. More recently, anelastic relaxation measurements in La2CuO4+delta, showed that the removal of this element can be related to two events. One is the decrease in mobility between two adjacent CuO planes, and the other is the increase in the number of tilting patterns of the CuO6 octahedra. For SmBa2Cu3O7 (SBCO, the possibility of variable stoichiometry and the high mobility of oxygen in the CuOx planes give rise to a rich phase diagram. In this paper, anelastic spectroscopy measurements are reported in SBCO samples which shown a thermally activated relaxation peak that was attributed to the jumps of the oxygen atoms in the inter-chains O1 and O5 of the lattice.

  2. Water driven enhanced photoluminescence of Ln (=Dy3+, Sm3+) doped LaVO4 nanoparticles and effect of Ba2+ co-doping

    International Nuclear Information System (INIS)

    Highlights: ► Dy3+ and Sm3+ doped LaVO4 nanoparticles prepared in water gives the highest luminescence intensity due to higher structure and site symmetries of tetragonal (t-) zircon phase. ► Water plays main role in the synthesis of tetragonal rare-earth doped LaVO4 nanoparticles, accountable to the phase change induced by strong interaction between water and the surface of LaVO4 nanoparticles. ► Luminescence intensity is enhanced upon the introduction of Ba2+ in LaVO4:Ln (Ln = Dy3+, Sm3+). ► Re-dispersible in polar solvents and can be incorporated in polymer film of PVA. -- Abstract: Well-dispersed Dy3+ and Sm3+ doped LaVO4 nanoparticles have been synthesized at a relatively low temperature of 140 °C in ethylene glycol (EG), water, N,N′-dimethyl formamide (DMF) and mixed solvents. The samples prepared in water show mixed tetragonal and monoclinic phase where tetragonal planes are found to be dominated over the monoclinic planes. However, the samples prepared in EG and DMF show monoclinic phase. Due to the phase transformation of the samples prepared in water the luminescence intensity of these samples is highly enhanced than that of the samples prepared in EG and DMF. The mixed phase of the samples prepared in water transformed to pure monoclinic phase when heated at 900 °C. The luminescence intensity of Dy3+ and Sm3+ doped LaVO4 prepared in EG are also enhanced when large divalent Ba2+ ions is used as co-activator. The optimum concentration for Ba2+ ions was found to be 1 at.% in both Dy3+ and Sm3+ doped systems. The prepared nanoparticles are subsequently dispersed in methanol and incorporated in polymer films of PVA which showed the characteristic emissions of Dy3+ and Sm3+ when irradiated under UV light

  3. Preparation and thermophysical properties of (Sm1−xErx)2Ce2O7 oxides for thermal barrier coatings

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • These ceramic materials with fluorite structure were synthesized. • Defect points lead to their lower thermal conductivities. • The lower ionic radius of Er3+ ion leads to the reduction of thermal expansion coefficient of (Sm1−xErx)2Ce2O7 oxides. - Abstract: (Sm1−xErx)2Ce2O7 ceramics were synthesized by sol–gel method and sintered at 1600 °C for 10 h in air. The influence of Er2O3-substitution on the phase structure and thermophysical properties of Sm2Ce2O7 was investigated. The phase structures of these ceramics were identified by X-ray diffraction showing that all synthesized ceramics have fluorite-type structure. The measurements for thermophysical properties of these ceramics show that their thermal conductivities and thermal expansion coefficients remarkably decreased through Er-substitution. However, the thermal expansion coefficients were higher than that of YSZ and their thermal conductivities were much lower than that of 8YSZ. The excellent thermophysical property implies that these solid solutions are potential materials for the ceramics layer in thermal barrier coatings

  4. Ultraviolet-vacuum ultraviolet photoluminescence and x ray radioluminescence of Ce3+-doped Ba3MgSi2O8

    NARCIS (Netherlands)

    Ding, X.; Liang, H.; Hou, D.; Su, Q.; Dorenbos, P.; Sun, S.; Tao, Y.

    2011-01-01

    Ce3+-doped Ba3MgSi2O8 phosphors were prepared by a solid-state reaction route. The photoluminescence properties in the vacuum ultraviolet-vis spectral range and the x ray excited radioluminescence were investigated. Ce3+ ions were found to enter three different sites in the host lattice. Five excita

  5. Sm 2NiSn 4: The intermediate structure type between ZrSi 2 and CeNiSi 2

    Science.gov (United States)

    Sun, Zhong-Ming; Pan, Da-Chun; Lei, Xiao-Wu; Mao, Jiang-Gao

    2006-11-01

    A new rare earth nickel stannide, Sm 2NiSn 4, has been prepared by reacting the pure elements at high temperature in welded tantalum tubes. Its crystal structure was established by single crystal X-ray diffraction studies. Sm 2NiSn 4 crystallizes in the orthorhombic space group Pnma (No. 62) with cell parameters of a=16.878(2) Å, b=4.4490(7) Å, c=8.915(1) Å, and Z=4. Its structure can be viewed as the intermediate type between ZrSi 2 and CeNiSi 2. Sm 2NiSn 4 features two-dimensional (2D) corrugated [NiSn 4] 6- layers in which the 1D Sn zigzag chains and the 2D Sn square sheets are bridged by Ni atoms. The Sm 3+ cations are located at the interlayer space. Results of both resistivity measurements and extended-Hückel tight-binding band structure calculations indicate that Sm 2NiSn 4 is metallic.

  6. Photon management properties of rare-earth (Nd,Yb,Sm)-doped CeO2 films prepared by pulsed laser deposition.

    Science.gov (United States)

    Balestrieri, Matteo; Colis, Silviu; Gallart, Mathieu; Schmerber, Guy; Bazylewski, Paul; Chang, Gap Soo; Ziegler, Marc; Gilliot, Pierre; Slaoui, Abdelilah; Dinia, Aziz

    2016-01-28

    CeO2 is a promising material for applications in optoelectronics and photovoltaics due to its large band gap and values of the refractive index and lattice parameters, which are suitable for silicon-based devices. In this study, we show that trivalent Sm, Nd and Yb ions can be successfully inserted and optically activated in CeO2 films grown at a relatively low deposition temperature (400 °C), which is compatible with inorganic photovoltaics. CeO2 thin films can therefore be efficiently functionalized with photon-management properties by doping with trivalent rare earth (RE) ions. Structural and optical analyses provide details of the electronic level structure of the films and of their energy transfer mechanisms. In particular, we give evidence of the existence of an absorption band centered at 350 nm from which energy transfer to rare earth ions occurs. The transfer mechanisms can be completely explained only by considering the spontaneous migration of Ce(3+) ions in CeO2 at a short distance from the RE(3+) ions. The strong absorption cross section of the f-d transitions in Ce(3+) ions efficiently intercepts the UV photons of the solar spectrum and therefore strongly increases the potential of these layers as downshifters and downconverters. PMID:26699802

  7. Diffusion of Zr, Ru, Ce, Y, La, Sr and Ba fission products in UO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Perriot, R., E-mail: rperriot@lanl.gov; Liu, X.-Y.; Stanek, C.R.; Andersson, D.A.

    2015-04-15

    The diffusivity of the solid fission products (FP) Zr (Zr{sup 4+}), Ru (Ru{sup 4+}, Ru{sup 3+}), Ce (Ce{sup 4+}), Y (Y{sup 3+}), La (La{sup 3+}), Sr (Sr{sup 2+}) and Ba (Ba{sup 2+}) by a vacancy mechanism has been calculated, using a combination of density functional theory (DFT) and empirical potential (EP) calculations. The activation energies for the solid fission products are compared to the activation energy for Xe fission gas atoms calculated previously. Apart from Ru, the solid fission products all exhibit higher activation energy than Xe. For all solid FPs except Y{sup 3+}, the migration of the FP has lower barrier than the migration of a neighboring U atom, making the latter the rate limiting step for direct migration. An indirect mechanism, consisting of two successive migrations around the FP, is also investigated. The calculated diffusivities show that most solid fission products diffuse with rates similar to U self-diffusion. However, Ru, Ba and Sr exhibit faster diffusion than the other solid FPs, with Ru{sup 3+} and Ru{sup 4+} diffusing even faster than Xe for T < 1200 K. The diffusivities correlate with the observed fission product solubility in UO{sub 2}, and the tendency to form metallic and oxide second phase inclusions.

  8. Magnetic penetration depth of Pr1.85Ce0.15CuO4 and Sm1.85Ce0.15CuO4 electron-doped superconductors

    International Nuclear Information System (INIS)

    In this work, we report the temperature dependence of the lambda penetration depth, λ(T) for Pr1.85Ce0.15CuO4 and Sm1.85Ce0.15CuO4 electron-doped superconductors. We have measured thin film samples of both compositions grown on STO substrates by using the pulsed laser deposition technique (PLD). λ(T) has been extracted by numerical analysis from the experimental mutual-inductance data obtained by using a home-made mutual-inductance bridge. We have found that they do not follow the conventional BCS behavior characteristic of other electron-doped superconductors like Nd1.85Ce0.15CuO4 and NbCN as recently reported

  9. Vertical Interface Induced Dielectric Relaxation in Nanocomposite (BaTiO3)1-x:(Sm2O3)x Thin Films

    Science.gov (United States)

    Li, Weiwei; Zhang, Wei; Wang, Le; Gu, Junxing; Chen, Aiping; Zhao, Run; Liang, Yan; Guo, Haizhong; Tang, Rujun; Wang, Chunchang; Jin, Kuijuan; Wang, Haiyan; Yang, Hao

    2015-06-01

    Vertical interfaces in vertically aligned nanocomposite thin films have been approved to be an effective method to manipulate functionalities. However, several challenges with regard to the understanding on the physical process underlying the manipulation still remain. In this work, because of the ordered interfaces and large interfacial area, heteroepitaxial (BaTiO3)1-x:(Sm2O3)x thin films have been fabricated and used as a model system to investigate the relationship between vertical interfaces and dielectric properties. Due to a relatively large strain generated at the interfaces, vertical interfaces between BaTiO3 and Sm2O3 are revealed to become the sinks to attract oxygen vacancies. The movement of oxygen vacancies is confined at the interfaces and hampered by the misfit dislocations, which contributed to a relaxation behavior in (BaTiO3)1-x:(Sm2O3)x thin films. This work represents an approach to further understand that how interfaces influence on dielectric properties in oxide thin films.

  10. Influence of surface morphology on the thickness dependence of high-Jc Sm1+xBa2-xCu3O6+δ films

    International Nuclear Information System (INIS)

    We have investigated a dependence of critical current density (Jc) on the thickness of Sm1+xBa2-xCu3O6+δ (SmBCO) films grown by pulsed laser deposition using x=0, 0.04 and 0.08 targets. Different behaviors were observed in the film thickness dependence of Jc of x=0, 0.04 and 0.08 SmBCO films. The Jc of x=0 and 0.04 SmBCO films decreased with increasing film thickness up to about 1 μm. In the region of the thickness over 1 μm, the x=0 and 0.04 SmBCO films maintained high-Jc and the highest critical current (Ic*) calculated for 1 cm-width of about 520 A/cm-width was obtained at a film thickness of 2.1 μm for x=0.04 film. On the other hand, the Jc of x=0.08 SmBCO film increased up to the film thickness of 1.1 μm and Ic* reached a high value of about 480 A/cm-width. However, in the region of the thickness over 1.1 μm, the Jc of x=0.08 film rapidly decreased. In this paper, we discuss how the difference of the precipitates affects the film thickness dependence of Jc. From the SEM and TEM observation of the film, we found the precipitates of x=0 and 0.08 films as BaCuO compounds and crystallized Cu2O, respectively. It is considered that the difference of the precipitates affects the film thickness dependence of Jc

  11. Phase Structure, Piezoelectric and Multiferroic Properties of SmCoO3-Modified BiFeO3-BaTiO3 Lead-Free Ceramics

    Science.gov (United States)

    Jiang, Na; Tian, Mijie; Luo, Lingling; Zheng, Qiaoji; Shi, Dongliang; Lam, Kwok Ho; Xu, Chenggang; Lin, Dunmin

    2016-01-01

    (0.75- x)BiFeO3-0.25BaTiO3- xSmCoO3 + 1 mol.% MnO2 lead-free multiferroic ceramics were synthesized by a conventional ceramic fabrication technique. The effects of SmCoO3 on phase structure, piezoelectricity and multiferroicity of the ceramics were studied. All the ceramics can be well sintered at a low sintering temperature of 960°C. The crystalline structure of the ceramics is transformed from rhombohedral to tetragonal symmetry with increasing the amount of SmCoO3. A morphotropic phase boundary of rhombohedral and tetragonal phases is formed at x = 0.01-0.04. A small amount of SmCoO3 is shown to improve the ferroelectric, piezoelectric and magnetoelectric properties of the ceramics. For the ceramics with x = 0.01-0.03, enhanced resistivity ( R ˜ 1.2 × 109 Ω cm to 2.1 × 109 Ω cm), piezoelectricity ( d 33 ˜ 65 pC/N to 106 pC/N) and ferroelectricity ( P r ˜ 6.38 μC/cm2 to 22.89 μC/cm2) are obtained. The ferromagnetism of the materials is greatly enhanced by the doping of SmCoO3 such that a very high magnetoelectric coefficient of ˜742 mV/(cm Oe) is obtained at x = 0.01, suggesting a promising potential in multiferroic devices.

  12. Fabrication of High-Quality SmBa2Cu3O7-δ Thin Films by a Modified TFA-MOD Process

    International Nuclear Information System (INIS)

    We report a successful fabrication of high-quality SmBa2Cu3O7-δ (SmBCO) thin films on LaAlO3(LAO)(100) single crystalline substrates by a modified TFA-MOD method. After the pyrolysis heat treatment of spin-coated films up to 400 degree C, SmBCO films were fired at various temperatures ranging from 810 to 850 degree C in a reduced oxygen atmosphere (10 ppm O2 in Ar). Optimally processed SmBCO films exhibited the zero-resistance temperature (Tc,zero) of 90.2 K and the critical current density (Jc) of 0.8 MA/cm2 at 77K in self-field. Compared with the Jc values (normally, > 2 MA/cm2 at 77 K) of MOD-TFA processed YBCO films, rather depressed Jc values in SmBCO films are most probably attributed to the existence of alpha-axis oriented grains.

  13. Study of vibrational spectroscopy, linear and non-linear optical properties of Sm3+ ions doped BaO-ZnO-B2O3 glasses

    Science.gov (United States)

    Nanda, Kirti; Kundu, R. S.; Sharma, Sarita; Mohan, Devendra; Punia, R.; Kishore, N.

    2015-07-01

    Samarium oxide doped Barium-Zinc-Borate glasses with compositions xSm2O3-(100-x)[0.1BaO-0.4ZnO-0.5B2O3]; x = 0.0, 0.5, 1.0, 1.5 and 2.0 have been prepared by melt quench technique. The amorphous nature of as-prepared glasses has been ascertained by X-ray diffraction patterns. The observed values of density and molar volume of the glass samples are found to increase with the increase in concentration of Sm2O3. Fourier Transform Infrared spectra of the prepared glasses indicate that Sm2O3 acts as glass modifier. With the increase in Sm2O3 content, BO4 structural units start converting into BO3 structural units. The values of optical energy band gap (Eg), estimated from Tauc's plots, are observed to decrease with the increase in Sm2O3 content. The nonlinear optical properties of glass samples have been investigated by Z-scan method with nanosecond pulsed laser at ˜532 nm in both open and close aperture geometries. The values of two photon absorption coefficient (β) and nonlinear refractive index (n2) have been estimated by fitting of experimentally observed data with theoretical models and both are found to increase with the increase in Sm3+ ions concentration in the glass matrix. The total third order nonlinear susceptibility (χ(3)) have been calculated and observed to increase with the increase in Sm3+ ions concentration.

  14. Electrical conductivity and chemical stability of BaCe0.8−AGd0.2O3− (A = In, Zr, Ta; = 0, 0.1) ceramics

    Indian Academy of Sciences (India)

    Xiao-Ming Liu; Yi-Jing Gu; Zhan-Guo Liu; Jia-Hu Ouyang; Fu-Yao Yan; Jun Xiang

    2013-06-01

    BaCe0.8−AGd0.2O3− (A = In, Zr, Ta; = 0, 0.1) ceramics were synthesized by solid-state reaction method. Microstructure and electrical properties of BaCe0.8−AGd0.2O3− ceramics were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and complex impedance analysis at intermediate temperatures of 573–1073 K in different atmospheres. BaCe0.8Gd0.2O3−, BaCe0.7In0.1Gd0.2O3− and BaCe0.7Zr0.1Gd0.2O3− ceramics exhibit a single cubic perovskite structure. BaCe0.7In0.1Gd0.2O3− ceramic has the highest conductivity of 4.6 × 10-2 S.cm-1 in air at 1073 K. BaCe0.7In0.1Gd0.2O3− and BaCe0.7Zr0.1Gd0.2O3− ceramics exhibit an excellent chemical stability against boiling water. Indium is a suitable doping element to promote the sintering densification and to enhance both electrical conductivity and chemical stability of Gd-doped BaCeO3 at operating temperatures.

  15. Magnetic properties of a new series of rare-earth iron nitrides R3(Fe, Mo)29Nx (R = Ce, Nd, Sm, Gd, Tb, Dy or Y)

    International Nuclear Information System (INIS)

    A series of interstitial nitrides R3(Fe, Mo)29Nx with 3.7≤x≤4.0 has been prepared for R = Ce, Nd, Sm, Gd, Tb, Dy or Y. The nitrides have structures related to Nd3(Fe, Ti)29, but the unit-cell volumes are 4.7-6.6% greater and the magnetic ordering temperatures some 224-361 K higher than those of the R3(Fe, Mo)29 parent compounds, and the saturation magnetizations Ms are also higher than those of the corresponding parent compounds. All compounds investigated exhibit easy-plane anisotropy at room temperature, except for Sm3(Fe, Mo)29Nx which is of an easy-axis nature. (author)

  16. Crystal structures of R{sub 2}Pd{sub 2}Pb (R = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Melnyk, G.; Kandpal, H.C.; Gulay, L.D.; Tremel, W

    2004-05-12

    The crystal structures of the R{sub 2}Pd{sub 2}Pb (R=Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu) compounds were determined using X-ray powder diffraction. The investigated compounds crystallize with Mo{sub 2}FeB{sub 2} structure type (space group P4/mbm, Pearson code tP10). The importance of stabilization by polar intermetallic R-Pd bonding is underscored by a bonding analysis derived from electronic band structure calculations.

  17. Crystal structures of the compounds R{sub 3}CuSiS{sub 7} (R = Ce, Pr, Nd, Sm, Tb, Dy and Er) and R{sub 3}CuSiSe{sub 7} (R = La, Ce, Pr, Nd, Sm, Gd, Tb and Dy)

    Energy Technology Data Exchange (ETDEWEB)

    Gulay, L.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine)]. E-mail: gulay@univer.lutsk.ua; Lychmanyuk, O.S. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Daszkiewicz, M. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna str. 2, P.O. Box 1410, 50-950 Wroclaw (Poland); Stepien-Damm, J. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna str. 2, P.O. Box 1410, 50-950 Wroclaw (Poland); Pietraszko, A. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna str. 2, P.O. Box 1410, 50-950 Wroclaw (Poland)

    2007-04-04

    The crystal structures of the compounds R{sub 3}CuSiS{sub 7} (R = Ce, Pr, Nd, Sm, Tb, Dy and Er) and R{sub 3}CuSiSe{sub 7} (R = La, Ce, Pr, Nd, Sm, Gd, Tb and Dy) (La{sub 3}CuSiS{sub 7} structure type, space group P6{sub 3}, Pearson symbol hP24) were determined by means of X-ray single crystal and powder diffraction. The R atoms are surrounded by distorted trigonal prisms. A triangular surrounding exists for the Cu atoms. A tetrahedral surrounding exists for the Si atoms. The S(Se)1 and S(Se)3 atoms are surrounded by tetrahedra also. Four cations surround every S(Se)2 atom.

  18. Sm-Ba-Cu-O bulk superconductors melt processed in air, using Nd123/MgO thin film cold seeding

    International Nuclear Information System (INIS)

    It is well known that melt processed REBaCuO (RE: rare-earth) superconductors have a high Jc at 77 K and high magnetic field, and that light rare-earth BaCuO has a larger Jc than Y123 in high magnetic field. High field applications such as a superconducting permanent magnet with the liquid nitrogen refrigeration and flywheels are expected. In this study, for improving superconducting properties and producing a larger bulk, we discuss Sm123 bulks melt processed in air and their characteristic superconducting properties. Isothermal undercooling growth in air with oxygen annealing and Nd123/MgO thin film cold seeding technique were applied in SmBaCuO/Ag system to seek the high efficiency of process, homogeneity of composition, and feasibility of batch production. We investigated process conditions such as heat treatment temperatures, compositions, seeding methods, and atmosphere. Single domain growth of superconducting phases of a square larger than 10 mm on a side and 10 mm in thickness was achieved using this technique. The result implies that melt processed in air applying isothermal method and thin film seeding in Sm system is feasible for producing larger bulks in large scale applications

  19. Luminescence properties and energy transfer in the novel red emitting phosphors Ba{sub 2}Ln(BO{sub 3}){sub 2}Cl:Sm{sup 3+}, Eu{sup 3+} (Ln=Y, Gd)

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yan; Hu, Yihua, E-mail: huyh@gdut.edu.cn; Chen, Li; Wang, Xiaojuan; Ju, Guifang

    2014-10-01

    A series of Sm{sup 3+}/Eu{sup 3+} singly and co-doped Ba{sub 2}Ln(BO{sub 3}){sub 2}Cl (Ln=Y{sup 3+}, Gd{sup 3+}) phosphors were prepared via the solid-state method. The XRD results indicate that the as-prepared products keep the monoclinic structure with a P{sub 21/m} space group of Ba{sub 2}Ln(BO{sub 3}){sub 2}Cl, which belongs to the isomorphic substitution for Ln{sup 3+} sites in the Ba{sub 2}Yb(BO{sub 3}){sub 2}Cl host. The photoluminescence (PL) spectra demonstrate that Ba{sub 2}Ln(BO{sub 3}){sub 2}Cl:Sm{sup 3+},Eu{sup 3+} emits red light centered at 593 nm under the 393 nm excitation which is in good agreement with the emission wavelength from near ultraviolet light-emitting diodes (LEDs). The luminescence decays suggest that the energy transfer from Sm{sup 3+} to Eu{sup 3+} ions in Ba{sub 2}Ln(BO{sub 3}){sub 2}Cl:Eu{sup 3+}, Sm{sup 3+} occurs. All results mean that Ba{sub 2}Ln(BO{sub 3}){sub 2}Cl:Eu{sup 3+}, Sm{sup 3+} phosphors exhibit potential to act as a kind of red phosphor for near ultraviolet white light-emitting diodes (w-LEDs)

  20. Luminescence properties and energy transfer in the novel red emitting phosphors Ba2Ln(BO3)2Cl:Sm3+, Eu3+ (Ln=Y, Gd)

    International Nuclear Information System (INIS)

    A series of Sm3+/Eu3+ singly and co-doped Ba2Ln(BO3)2Cl (Ln=Y3+, Gd3+) phosphors were prepared via the solid-state method. The XRD results indicate that the as-prepared products keep the monoclinic structure with a P21/m space group of Ba2Ln(BO3)2Cl, which belongs to the isomorphic substitution for Ln3+ sites in the Ba2Yb(BO3)2Cl host. The photoluminescence (PL) spectra demonstrate that Ba2Ln(BO3)2Cl:Sm3+,Eu3+ emits red light centered at 593 nm under the 393 nm excitation which is in good agreement with the emission wavelength from near ultraviolet light-emitting diodes (LEDs). The luminescence decays suggest that the energy transfer from Sm3+ to Eu3+ ions in Ba2Ln(BO3)2Cl:Eu3+, Sm3+ occurs. All results mean that Ba2Ln(BO3)2Cl:Eu3+, Sm3+ phosphors exhibit potential to act as a kind of red phosphor for near ultraviolet white light-emitting diodes (w-LEDs)

  1. Crystal structures and magnetic properties of R{sub 2}PbSi{sub 2}S{sub 8} (R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho), R{sub 2}PbSi{sub 2}Se{sub 8} (R = La, Ce, Pr, Nd, Sm, Gd) and R{sub 2}PbGe{sub 2}S{sub 8} (R = Ce, Pr) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Daszkiewicz, M. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Marchuk, O.V. [Department of Inorganic and Physical Chemistry, Volyn National University, Voli Ave 13, 43009 Lutsk (Ukraine); Gulay, L.D. [Department of Ecology and Protection of Environment, Volyn National University, Voli Ave 13, 43009 Lutsk (Ukraine); Kaczorowski, D., E-mail: D.Kaczorowski@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland)

    2012-04-05

    The crystal structures of several novel quaternary compounds R{sub 2}PbSi{sub 2}S{sub 8} (R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho), R{sub 2}PbSi{sub 2}Se{sub 8} (R = La, Ce, Pr, Nd, Sm, Gd) and R{sub 2}PbGe{sub 2}S{sub 8} (R = Ce, Pr) have been determined by means of single-crystal and powder X-ray diffraction. All these phases crystallize with hexagonal unit cells of the La{sub 2}PbSi{sub 2}S{sub 8} type (space group R-3c, Pearson symbol hR78), in which rare-earth and lead atoms are statistically distributed over centers of bi-capped trigonal prisms made by chalcogen atoms. The magnetic properties of R{sub 2}PbSi{sub 2}S{sub 8} and R{sub 2}PbSi{sub 2}Se{sub 8} with R = La, Ce, Pr and Sm have been studied in wide temperature and magnetic field ranges. The La-based materials are weakly diamagnetic, whereas all the other compounds exhibit strongly temperature dependent paramagnetic behaviour due to the presence of well localized magnetic moments of trivalent rare-earth ions.

  2. Synthesis and in vitro microbial evaluation of La(III), Ce(III), Sm(III) and Y(III) metal complexes of vitamin B6 drug

    Science.gov (United States)

    Refat, Moamen S.; Al-Azab, Fathi M.; Al-Maydama, Hussein M. A.; Amin, Ragab R.; Jamil, Yasmin M. S.

    2014-06-01

    Metal complexes of pyridoxine mono hydrochloride (vitamin B6) are prepared using La(III), Ce(III), Sm(III) and Y(III). The resulting complexes are investigated. Some physical properties, conductivity, analytical data and the composition of the four pyridoxine complexes are discussed. The elemental analysis shows that the formed complexes of La(III), Ce(III), Sm(III) and Y(III) with pyridoxine are of 1:2 (metal:PN) molar ratio. All the synthesized complexes are brown in color and possess high melting points. These complexes are partially soluble in hot methanol, dimethylsulfoxide and dimethylformamide and insoluble in water and some other organic solvents. Elemental analysis data, spectroscopic (IR, UV-vis. and florescence), effective magnetic moment in Bohr magnetons and the proton NMR suggest the structures. However, definite particle size is determined by invoking the X-ray powder diffraction and scanning electron microscopy data. The results obtained suggested that pyridoxine reacted with metal ions as a bidentate ligand through its phenolate oxygen and the oxygen of the adjacent group at the 4‧-position. The molar conductance measurements proved that the pyridoxine complexes are electrolytic in nature. The kinetic and thermodynamic parameters such as: Ea, ΔH*, ΔS* and ΔG* were estimated from the DTG curves. The antibacterial evaluation of the pyridoxine and their complexes were also performed against some gram positive, negative bacteria as well as fungi.

  3. Synthesis, spectroscopic and antimicrobial studies of La(III), Ce(III), Sm(III) and Y(III) Metformin HCl chelates

    Science.gov (United States)

    Refat, Moamen S.; Al-Azab, Fathi M.; Al-Maydama, Hussein M. A.; Amin, Ragab R.; Jamil, Yasmin M. S.; Kobeasy, Mohamed I.

    2015-05-01

    Metal complexes of Metformin hydrochloride were prepared using La(III), Ce(III), Sm(III) and Y(III). The resulting complexes were discussed and synthesized to serve as potential insulin-mimetic. Some physical properties and analytical data of the four complexes were checked. The elemental analysis shows that La(III), Ce(III) Sm(III) and Y(III) formed complexes with Metformin in 1:3 (metal:MF) molar ratio. All the synthesized complexes are white and possess high melting points. These complexes are soluble in dimethylsulfoxide and dimethylformamide, partially soluble in hot methanol and insoluble in water and some other organic solvents. From the spectroscopic (infrared, UV-vis and florescence), effective magnetic moment and elemental analyses data, the formula structures are suggested. The results obtained suggested that Metformin reacted with metal ions as a bidentate ligand through its two imino groups. The molar conductance measurements proved that the Metformin complexes are slightly electrolytic in nature. The kinetic thermodynamic parameters such as: E∗, ΔH∗, ΔS∗ and ΔG∗ were estimated from the DTG curves. The antibacterial evaluations of the Metformin and their complexes were also performed against some gram positive, negative bacteria as well as fungi.

  4. Luminescent properties and energy transfer process of Sm3+-Eu3+ co-doped MY2(MoO4)4 (M=Ca, Sr and Ba) red-emitting phosphors

    Science.gov (United States)

    Ye, Menglin; Zhou, Gaojian; Zhou, Liqun; Lu, Di; Li, Yue; Xiong, Xing; Yang, Kunzhou; Chen, Menghuan; Pan, Yaxi; Wu, Peng; Wang, Zheng; Liu, Hongying; Xia, Qinghua

    2016-09-01

    MY2(MoO4)4:Sm3+ and MY2(MoO4)4:xSm3+,yEu3+ (M=Ca, Sr and Ba) phosphors were successfully prepared using solid-state reaction route, and their luminescent properties and energy transfer process from Sm3+ to Eu3+ were systematically investigated. The results indicate that MY2(MoO4)4:Sm3+ phosphors can be effectively excited by 407 nm near UV light originating from the 6H5/2 → 4F7/2 transition of Sm3+, and exhibit a satisfactory red emission at 646 nm attributed to the 4G5/2 → 6H9/2 transition of Sm3+, in which the emission intensity of SrY2(MoO4)4:Sm3+ is the strongest among the MY2(MoO4)4:Sm3+ (M=Ca, Sr and Ba) phosphors. For Eu3+ co-doped MY2(MoO4)4:Sm3+ samples, with increasing Eu3+ doping content, the main emission peaks of Sm3+ (approximately 646 nm) are decreased, but the emission peaks and intensity of Eu3+ are increased while the maximum intensity of luminescence at the Eu3+ concentration 0.9. The introduction of Eu3+ in the MY2(MoO4)4:Sm3+ phosphors can remarkably generate a strong emission line at 616 nm, originating from the 5D0→7F2 transition of Eu3+ and Sm3+ (4G5/2) → Eu3+ (5D0) effective energy transfer process. The energy transfer mechanism from Sm3+ to Eu3+ was discussed in detail.

  5. Enhanced characteristics of Ba5SmTi3Nb7O30 ferroelectric nanocrystalline ceramic prepared by mechanical activation process: A comparative study

    International Nuclear Information System (INIS)

    Graphical abstract: In the present work, structural, dielectric, ferroelectric, piezoelectric and pyroelectric properties of tungsten-bronze structured Ba5SmTi3Nb7O30 ceramics, synthesized by mechanical activation and conventional solid-state reaction processes, have been studied with an objective of comparing the properties of the specimens synthesized by the two processes. The specimen prepared using mechanical activation process exhibits improved structural and electrical properties. Research highlights: → In this report Ba5SmTi3Nb7O30 compounds have been synthesized. → Synthesis was carried out by mechanical activation and solid-state reaction processes. → The mechanical activation process yields nanocrystalline specimen. → The synthesized specimens were characterized for their electrical properties. → A comparative study reveals that nanocrystalline specimen possesses superior properties. -- Abstract: In the present work, structural, dielectric, ferroelectric, piezoelectric and pyroelectric properties of tungsten-bronze structured Ba5SmTi3Nb7O30 ceramics, synthesized by mechanical activation and conventional solid-state reaction processes, have been studied with an objective of comparing the properties of the specimens synthesized by the two processes. X-ray diffraction analysis shows the formation of the compound in an orthorhombic structure by both the processes. Scanning electron microscopy reveals the formation of a fine granular microstructure in the specimen synthesized by mechanical activation process compared to the specimen synthesized by conventional solid-state method. The specimen prepared using mechanical activation process exhibits improved electrical properties with higher dielectric constant, lower dielectric loss and higher resistivity. The effective remanent polarization (P-barr) value, d33 value and pyroelectric coefficients are also observed to be higher in the sample synthesized by the mechanical activation process.

  6. Y3Al5O12:Re3+ (Re=Ce, Eu, and Sm nanocrystalline powders prepared by modified glycine combustion method

    Directory of Open Access Journals (Sweden)

    Lojpur V.

    2014-01-01

    Full Text Available Yttrium aluminum garnet doped with rare earth ions (Ce3+, Eu3+ and Sm3+ was prepared by modified glycine method. Ce3+ as a dopant was used in four different concentrations (Y3-xCexAl5O12; x(% = 1, 2, 3, 5, while doping concentration of Eu3+ and Sm3+ was Y3-xEuxAl5O12; x(% = 3 and Y3-xSmxAl5O12; x(% = 1, respectively. Phase composition of powders was investigated using XRD technique and expected target phase was confirmed. Photoluminescent characterization included measurements of excitation and emission spectra, as well as determination of emission decays. Y3-xCexAl5O12 shows intense broad-band emission, with maximum in green spectral region, at about 524 nm under ultraviolet or blue excitation. The origin of the luminescence is the 5d1→4f1 transition which is both parity and spin allowed. Ultraviolet and blue excitations of Eu3+ and Sm3+ doped Y3Al5O12 produce intense orange and red emissions. These emissions are phosphorescent in character and come from spin forbidden f-f electron transitions in Eu3+ and Sm3+ ions. For the case of Eu3+ doping emission comes mainly from 5D0→7F1 transitions with Stark components peaking at 590 nm and 590.75 nm, and with emission decay of 4.15 ms. In the case of Sm3+ doping, the emission spectrum, shows 4G5/2→6H5/2, 4G5/2→6H7/2, and 4G5/2→6H9/2 transitions, with the most intense stark components positioned at 567.5 nm, 617 nm, and 650 nm, respectively and for transition centered at 617 nm, emission decay is 3.12 ms. [Projekat Ministarstva nauke Republike Srbije, br. 171022 i br. 45012

  7. Phase Relations in Ba6−3xLn8+2xTi18O54 (Ln = Nd & Sm Electroceramics

    Directory of Open Access Journals (Sweden)

    Amanda L. Snashall

    2013-01-01

    x=0.33, ceramics with high Sm content are found to experience a severe degradation of Qf and changes in τcf trending, associated with the onset of globular and needle-like grain morphology and a Ba-Ti rich phase. x=0.67 ceramics with high Nd content are found to exhibit a secondary phase (Nd2Ti2O7 upon prolonged sintering which resulted in beneficial changes to Qf and τcf without affecting εr. Two BLnTss ceramics compositions with near-zero τcf were successfully synthesised with high Qf and εr values.

  8. Preparation and Electrical Property of Ba1.03Ce0.8Ho0.2O3-α Solid Electrolyte

    Institute of Scientific and Technical Information of China (English)

    WANG, Maoyuan; QIU, Ligan; SUN, Yufeng

    2009-01-01

    Ba1.03Ce0.8Ho0.2O3-α solid electrolyte with nonstoichiometric composition was prepared by high temperature solid-state reaction. Phase composition, surface and fracture morphologies of the material were characterized by using XRD and SEM, respectively. Ionic transport number and conductivity of the material were measured by gas concentration cell and ac impedance spectroscopy methods in the temperature range of 600-1000 ℃ in dry air, wet air and wet hydrogen, respectively. Ionic conduction was researched and compared with those of BaCe0.8Ho0.2O3-α and Ba0.970.8Ho0.2O3-α. The results indicate that Ba1.03Ce0.8Ho0.2O3-α is a single-phase perovskite-type orthorhombic system. In the temperature range of 600-1000 ℃, it is a mixed conductor of oxide ion and electron hole with the oxide ionic transport number of 0.10-0.36 in dry air atmosphere, a mixed conductor of proton, oxide ion and electronic hole with the protonic transport number of 0.11-0.01 and the oxide ionic trans- port number of 0.34-0.30 in wet air atmosphere, and a pure protonic conductor with the protonic transport number ionic conduction is superior to that of BaCe0.8Ho0.2O3-α and Ba0.97Ce0.8Ho0.2O3-α under the experimental conditions.

  9. Solubility and superconductivity in RE(Ba2-xREx)Cu3O7+δ (RE = Nd, Sm, Eu, Gd, Dy)

    International Nuclear Information System (INIS)

    Solid solutions of RE(Ba2-xREx)Cu3O7-δ(RE=Nd,Sm,Eu,Gd,Dy) for x=0 to x=0.5 have been investigated. X-ray and resistivity measurements show that there exists a solid solution region, through which, the structure changes from orthorhombic to tetragonal and the superconducting properties are depressed. The solubility limits depend strongly on the size of the rare-earth ion, with the smallest (Dy) showing no appreciable solubility. The superconducting transition temperature versus x for all of the rare-earth ion substitutions falls on a universal curve, indicating that the Ba sites are extremely ionic and magnetically isolated. 20 refs., 4 figs

  10. Crystal Structures and Magnetic Properties of 6H-Perovskites Ba 3MRu 2O 9 ( M=Y, In, La, Sm, Eu, and Lu)

    Science.gov (United States)

    Doi, Yoshihiro; Matsuhira, Kazuyuki; Hinatsu, Yukio

    2002-05-01

    Magnetic properties of quaternary oxides Ba3MRu2O9 (M=Y, In, La, Sm, Eu, and Lu) are reported. Rietveld analyses of the X-ray diffraction data indicate that they adopt the 6H-perovskite structure and have the valence state of Ba3M3+ Ru4.5+2O9. All compounds are nonmetallic at least over the temperature range of 100-400 K. The magnetic susceptibilities show a broad maximum at 135-370 K except for the La compound, which shows a plateau around 22 K. In addition, another magnetic anomaly is observed at 4.5-12.5 K by the magnetic susceptibility and specific heat measurements for any compound. It is considered that this magnetic behavior is ascribed to the antiferromagnetic coupling between two Ru ions in a Ru2O9 dimer and to the magnetic interaction between the Ru2O9 dimers.

  11. Stable and Vibrational Octupole Modes in Mo, Xe, Ba, La, Ce and Nd

    International Nuclear Information System (INIS)

    Evidence is presented for stable octupole deformation in neutron-rich nuclei, bounded by Z = 54-58 and N = 85-92. To either side of this region negative parity bands built on more vibrational type octupole modes are observed in 140Ba and 152,154Nd. The largest stable octupole deformation (βs ∼ 0.1) is found in 144Baas. The theoretically predicted quenching (βs ∼ 0) of stable octupole deformation at higher spins is found in 140Ba. There is good agreement between theory and experiment for the strongly varying electric dipole moments as a function of mass for 142-141Ba. In odd-A 142Ba and odd-Z 140La, we observe parity doublets, two pairs of positive and negative parity bands with opposite spins. In 145La a strong coupled ground band with symmetric shape coexists with the asymmetric octupole shape which stabilizes above about spin 19/2. In 145,147La a strong reduction in E2 strength around 25/2 from band crossing is observed. The isotope 109Mo was identified and a new region of stable uctpole deformation is identified in 107,108Mo centered around N = 64-66 as earlier predicted. This is the first case of stable uctpole deformation involving only one pair of orbitals

  12. Vacuum ultraviolet-ultraviolet and x-ray excited luminescence properties of Ba3Gd(BO3)3:Ce3+

    NARCIS (Netherlands)

    Han, B.; Liang, H.; Lin, H.; Zhong, J.; Su, Q.; Dorenbos, P.; Birowosuto, M.D.; Zhang, G.; Fu, Y.

    2007-01-01

    The phosphors Ba3Gd(BO3)3:Ce3+ were prepared by a solid-state reaction technique at high temperature. The vacuum ultraviolet-ultraviolet and visible spectroscopic properties of the phosphors together with decay time curves are investigated and discussed. The spectroscopic properties are explained by

  13. Structural and {sup 121}Sb Moessbauer spectroscopic investigations of the antimonide oxides REMnSbO (RE = La, Ce, Pr, Nd, Sm, Gd, Tb) and REZnSbO (RE = La, Ce, Pr)

    Energy Technology Data Exchange (ETDEWEB)

    Schellenberg, I.; Nilges, T.; Poettgen, R. [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2008-07-15

    Quaternary antimonide oxides REMnSbO (RE = La, Ce, Pr, Nd, Sm, Gd, Tb) and REZnSbO (RE = La, Ce, Pr) were synthesized from the RESb monoantimonides and MnO, respectively ZnO, in sealed tubes at 1170 K. Single crystals were obtained from NaCl/KCl salt fluxes. The ZrCuSiAs-type (space group P4/nmm) structures of LaMnSbO (a = 423.95(7), c = 955.5(27) pm, wR2 = 0.067, 247 F{sup 2}), CeMnSbO (a = 420.8(1), c = 950.7(1) pm, wR2 = 0.097, 250 F{sup 2}), SmMnSbO (a = 413.1(1), c = 942.3(1) pm, wR2 = 0.068, 330 F{sup 2}), LaZnSbO (a = 422.67(6), c = 953.8(2) pm, wR2 = 0.052, 259 F{sup 2}), and NdZnSbO (a = 415.9(1), c = 945.4(4) pm, wR2 = 0.109, 206 F{sup 2}) were refined from single crystal X-ray diffractometer data. The structures consist of covalently bonded (RE{sup 3+}O{sup 2-}){sup +} and (T{sup 2+}Sb{sup 3-}){sup -} layers with weak ionic interlayer interactions. The oxygen and transition metal atoms both have tetrahedral coordination within the layers. {sup 121}Sb Moessbauer spectra of the REMnSbO and REZnSbO compounds show single antimony sites with isomer shifts close to -8 mm s{sup -1}, in agreement with the antimonide character of these compounds. PrMnSbO and NdMnSbO show transferred hyperfine fields of 8 T at 4.2 K. (orig.)

  14. Influence of the Gd.sub.2./sub.BaCuO.sub.5./sub. fine particles on thermoelectric power of melt-textured (Nd-Sm-Gd) Ba.sub.2./sub.Cu.sub.3./sub.O.sub.7 -.delta../sub.

    Czech Academy of Sciences Publication Activity Database

    Okram, G. A.; Muralidhar, M.; Jirsa, Miloš; Murakami, M.

    2004-01-01

    Roč. 402, - (2004), s. 94-97. ISSN 0921-4534 Institutional research plan: CEZ:AV0Z1010914 Keywords : melt-textured materials * thermoelectric power * (Nd,Sm,Gd)Ba 2 Cu 3 O y * Gd 2 BaCuO 5 Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.072, year: 2004

  15. Ultra-large current transport in thick SmBa2Cu3O7−x films grown by reactive co-evaporation

    International Nuclear Information System (INIS)

    Highlights: • Transport properties of 5 μm thick SmBa2Cu3O7−x thin films were investigated. • Laser scanning microscopy was used to demonstrate local transport properties. • Temperature variable laser scanning microscopy shows correlation between structural and transport properties. • Optical measurements described nature of current transport properties in the coated conductors. - Abstract: Structural and transport properties of high performance SmBa2Cu3O7−x coated conductors produced by a dual-chamber co-evaporation are presented. The 5 μm-thick SmBCO coated conductors grown on IBAD-MgO based Hastelloy metal templates show critical currents larger than 1020–1560 A/cm at 77 K and self-field. The current transport characteristics of the conductors are investigated by room-temperature thermoelectric microscopy and low-temperature bolometric microscopy. The local thermoelectric images show the tilted grains, grain boundaries, and microstructural defects on the surface of the coated conductors. The bias current-dependent bolometric response at low temperature displays the current of the local flux flow dissipation as an increasing bias. Furthermore, we measured micro-Raman scattering microscopic imaging on oxygen-related peaks of the conductors. Comparing the Raman signal images with the low temperature optical scanning maps, it is remarkable that the structural disorders represented by oxygen-related Raman peaks are closely related to the low temperature bolometric abnormalities. From this result, a nature of the dissipative current distribution in coated conductors is revealed. The scanning optical microscopic study will provide a promising method for quality assurance of coated conductors

  16. Al–Mg–RE (RE = La, Ce, Pr, Nd, Sm) systems: Thermodynamic evaluations and optimizations coupled with key experiments and Miedema’s model estimations

    International Nuclear Information System (INIS)

    Highlights: ► Key experiments were made in Mg-rich corner of Al–Mg–RE (La, Ce, Pr, Nd) systems. ► Solid solubilities of Al in Mg12La, Mg12Ce, Mg12Pr, Mg41Nd5 were investigated. ► Miedema’s model was used to estimate the ΔHf for ternary compounds. ► The Al–Mg–Pr and Al–Mg–Nd ternary systems were optimized for the first time. ► Systematic thermodynamic evaluations and optimizations of Al–Mg–RE systems. -- Abstract: The solid solubilities of Al in Mg12La, Mg12Ce, Mg12Pr, Mg41Nd5 phases were investigated by key experiments. The enthalpy of formation of ternary compounds was estimated using the model of Miedema. The systematic thermodynamic evaluation and optimizations of ternary Al–Mg–RE (RE = La, Ce, Pr, Nd, Sm) systems were based on the available experimental data and current investigation. The Al–Mg–Pr and Al–Mg–Nd systems were optimized for the first time using a systematic approach. Arc-melted key alloys were annealed at T = 673 K for four weeks and the phases were analyzed with electron probe micro-analysis (EPMA). The Mg12La intermetallic phase was confirmed by the present investigation. Optimized model parameters have been obtained for the Gibbs energy functions of all stable phases, and the model reproduces most critically assessed experimental results. The Modified Quasichemical Model, which takes short–range ordering into account, is used for the liquid phase and the Compound Energy Formalism (CEF) is used for the solid solutions in the binary and ternary systems. Kohler–type extrapolation from binary systems was employed, where no ternary parameters were used for the liquid phase

  17. Synthesis, thermal and spectroscopic behaviors of metal-drug complexes: La(III), Ce(III), Sm(III) and Y(III) amoxicillin trihydrate antibiotic drug complexes

    Science.gov (United States)

    Refat, Moamen S.; Al-Maydama, Hussein M. A.; Al-Azab, Fathi M.; Amin, Ragab R.; Jamil, Yasmin M. S.

    2014-07-01

    The metal complexes of Amoxicillin trihydrate with La(III), Ce(III), Sm(III) and Y(III) are synthesized with 1:1 (metal:Amox) molar ratio. The suggested formula structures of the complexes are based on the results of the elemental analyses, molar conductivity, (infrared, UV-visible and fluorescence) spectra, effective magnetic moment in Bohr magnetons, as well as the thermal analysis (TG), and characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results obtained suggested that Amoxicillin reacted with metal ions as tridentate ligands, coordinating the metal ion through its amino, imino, and β-lactamic carbonyl. The kinetic thermodynamic parameters such as: Ea, ΔH*, ΔS* and ΔG* were estimated from the DTG curves.

  18. Ground state properties of even-even and odd Nd,Ce and Sm isotopes in Hartree-Fock-Bogoliubov method

    CERN Document Server

    Bassem, Younes El

    2015-01-01

    In this work, we have studied ground-state properties of both even-even and odd Nd isotopes within Hartree-Fock-Bogoliubov method with SLy5 Skyrme force in which the pairing strength has been generalized with a new proposed formula. We calculated bind- ing energies, two-neutron separation energies, quadrupole deformation, charge, neutron and proton radii. Similar calculations have been carried out for Ce and Sm in order to verify the validity of our pairing strength formula. The results have been compared with available experimental data, the results of Hartree-Fock-Bogoliubov calculations based on the D1S Gogny effective nucleon-nucleon interaction and predictions of some nuclear models such as Finite Range Droplet Model (FRDM) and Relativistic Mean Field (RMF) theory.

  19. Thermopower, Hall effect and magnetoresistivity of Ru 1- xSb xSr 2Sm 1.5Ce 0.5Cu 2O 10- d

    Science.gov (United States)

    Ilonca, G.; Patapis, S.; Beiusan, F.; Lung, C.; Toma, V.; Balint, P.; Bodea, M.; Jurcut, T.

    2007-09-01

    Magnetoresistivity, thermopower and Hall effect on the samples of Ru1-xSbxSr2Sm1.5Ce0.5Cu2O10-d were investigated in the temperature range 4-300 K with a magnetic field up to 9 T. Superconducting transition temperature decreases with increases content of Sb, due to a distortion of RuO6 octahedral, which is responsible of the increase in hole localization, reflected by Hall concentration, too. The inhomogeneous granular structure is put in evidence by the intragranular, Tco, and intergranular Tcg, transition temperatures. Hall effect and thermopower anomalous decreases below Tmagnetic can be explained within a simple two-band model by a transition from localized to more itinerant behavior in the RuO2 layer at Tmagnetic.

  20. Structural trends from a consistent set of single-crystal data of RFeAsO (R = La, Ce, Pr, Nd, Sm, Gd, and Tb)

    International Nuclear Information System (INIS)

    A new crystal growth technique for single crystals of RFeAsO (R = La, Ce, Pr, Nd, Sm, Gd, and Tb) using NaI/KI as flux is presented. Crystals with a size up to 300 μm were isolated for single-crystal X-ray diffraction measurements. Lattice parameters were determined by LeBail fits of X-ray powder data against LaB6 standard. A consistent set of structural data is obtained and interpreted in a hard-sphere model. Effective radii for the rare-earth metal atoms in RFeAsO are deduced. The relation of the intraplane and interplane distances of the arsenic atoms is identified as limiter of the phase formation, and its influence on Tc is discussed.

  1. Clarification and mitigation of marked J c decrease at low magnetic fields of BaHfO3-doped SmBaCuO3 thin films deposited on seed layer

    Science.gov (United States)

    Watanabe, Yutaro; Ichino, Yusuke; Yoshida, Yutaka; Ichinose, Ataru

    2016-07-01

    In accordance with the results of our previous research, a low-temperature growth (LTG) technique is effective for expanding the lower growth temperature region of c-axis-orientated SmBa2Cu3O y (SmBCO) thin films. However, BaHfO3 (BHO)-doped LTG films show a marked decrease in J c at low magnetic fields compared with conventional PLD films. In this study, we aimed to clarify the mechanism of J c decrease and investigated the thickness dependence of the seed layer on the (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) (100) single crystal. The obtained results indicate that J c decreased at low magnetic fields as the thickness of the seed layer increased. It is suggested that flux line kinks produced by flux motion in the seed layer would lead to the depinning of flux lines from BHO nanorods in the upper layer. Thus, we added Y2O3 into the seed layer to trap flux lines in the seed layer. Consequently, we improved J c in the low magnetic field region even in the films prepared by using the LTG technique.

  2. Crystal structures of the R{sub 2}CuInS{sub 5} (R=La, Ce, Pr, Nd and Sm) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Huch, M.R. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave. 13, Lutsk 43009 (Ukraine); Gulay, L.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave. 13, Lutsk 43009 (Ukraine)]. E-mail: gulay@univer.lutsk.ua; Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave. 13, Lutsk 43009 (Ukraine); Pietraszko, A. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna str. 2, P.O. Box 1410, Wroclaw 50-950 (Poland)

    2006-11-30

    The crystal structures of the R{sub 2}CuInS{sub 5} (R = La, Ce, Pr, Nd, Sm) compounds (space group Pnma, Pearson symbol oP36) were determined by means of X-ray single crystal diffraction (a = 1.1487(2) nm, b = 0.39760(8) nm, c 1.6911(3) nm, R1 = 0.0250 for La{sub 2}CuInS{sub 5}) and X-ray powder diffraction (a 1.14396(7) nm, b = 0.39361(2) nm, c = 1.6804(1) nm, R {sub Bragg} = 0.0937 for Ce{sub 2}CuInS{sub 5}; a = 1.14123(6) nm, b = 0.39119(2) nm, c = 1.6737(1) nm, R {sub Bragg} = 0.0974 for Pr{sub 2}CuInS{sub 5}; a = 1.13948(6) nm, b = 0.38933(2) nm, c = 1.66886(9) nm, R {sub Bragg} = 0.0853 for Nd{sub 2}CuInS{sub 5}; a = 1.13671(7) nm, b = 0.38594(2) nm, c = 1.6603(1) nm, R {sub Bragg} = 0.0887 for Sm{sub 2}CuInS{sub 5}). The R-centered trigonal prisms, Cu-centered tetrahedra and In-centered octahedra can be selected in the crystal structures of the R{sub 2}CuInS{sub 5} compounds.

  3. Crystal structures of the R{sub 3}CuSnSe{sub 7} (R = La, Ce, Pr, Nd, Sm, Gd, Tb and Dy) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gulay, L.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine)]. E-mail: gulay@lab.univer.lutsk.ua; Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine)

    2005-02-22

    The crystal structures of the R{sub 3}CuSnSe{sub 7} (R = La, Ce, Pr, Nd, Sm, Gd, Tb and Dy) compounds (La{sub 3}CuSiS{sub 7} structure type, space group P6{sub 3}, Pearson symbol hP24) were determined by means of X-ray powder diffraction: a 1.07211(1) nm, c = 0.62770(1) nm, R{sub I} = 0.0613 (La{sub 3}CuSnSe{sub 7}); a = 1.06310(2) nm, c = 0.62562(1) nm, R{sub I} = 0.0737 (Ce{sub 3}CuSnSe{sub 7}); a = 1.05613(4) nm, c 0.62532(3) nm, R{sub I} = 0.0964 (Pr{sub 3}CuSnSe{sub 7}); a = 1.05002(4) nm, c = 0.62523(2) nm, R{sub I} = 0.0808 (Nd{sub 3}CuSnSe{sub 7}); a = 1.03809(2) nm, c = 0.62848(2) nm, R{sub I} 0.0745 (Sm{sub 3}CuSnSe{sub 7}); a = 1.02435(2) nm, c = 0.63409(2) nm, R{sub I} = 0.0834 (Gd{sub 3}CuSnSe{sub 7}); a = 1.01894(2) nm, c = 0.63642(2) nm, R{sub I} = 0.0881 (Tb{sub 3}CuSnSe{sub 7}); a = 1.01359(3) nm, c = 0.63809(3) nm, R{sub I} = 0.0916 (Dy{sub 3}CuSnSe{sub 7})

  4. Crystal structures of the R{sub 3}CuGeSe{sub 7} (R = Ce, Pr, Nd, Sm, Gd, Tb and Ho) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gulay, L.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine)]. E-mail: gulay@univer.lutsk.ua; Lychmanyuk, O.S. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Pietraszko, A. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna str. 2, P.O. Box 1410, 50-950 Wroclaw (Poland)

    2006-09-28

    The crystal structures of the R{sub 3}CuGeSe{sub 7} compounds (R = Ce, Pr, Nd, Sm, Gd, Tb and Ho) (La{sub 3}CuSiS{sub 7} structure type, space group P6{sub 3}, Pearson symbol hP24) were determined by means of X-ray single crystal diffraction (a 1.0643(1) nm, c = 0.60973(7) nm, R1 = 0.0269 for Ce{sub 3}CuGeSe{sub 7}; a = 1.0559(1) nm, c = 0.6084(1) nm, R1 = 0.0301 for Pr{sub 3}CuGeSe{sub 7}; a = 1.0519(1) nm, c 0.60707(9) nm, R1 = 0.0305 for Nd{sub 3}CuGeSe{sub 7}) and X-ray powder diffraction (a = 1.04216(3) nm, c = 0.60447(3) nm, R {sub Bragg} = 0.0862 for Sm{sub 3}CuGeSe{sub 7}; a = 1.03491(8) nm, c = 0.60395(7) nm, R {sub Bragg} = 0.0932 for Gd{sub 3}CuGeSe{sub 7}; a = 1.02940(5) nm, c = 0.60387(4) nm, R {sub Bragg} = 0.0734 for Tb{sub 3}CuGeSe{sub 7}; a = 1.01978(7) nm, c = 0.60612(6) nm for Ho{sub 3}CuGeSe{sub 7}). The R atoms are surrounded by distorted trigonal prisms. A triangular surrounding exists for the Cu atoms. A tetrahedral surrounding exists for the Ge atoms.

  5. Crystallographic axis transition of Sm.sub.1+x./sub.Ba.sub.2-x./sub.Cu.sub.3./sub.O.sub.7-δ./sub. film prepared by liquid phase epitaxy (LPE)

    Czech Academy of Sciences Publication Activity Database

    Tang, Ch.Y.; Cai, Y.Q.; Li, W.; Sun, J.L.; Yao, X.; Jirsa, Miloš

    2009-01-01

    Roč. 9, č. 3 (2009), s. 1339-1343. ISSN 1528-7483 R&D Projects: GA ČR GA202/08/0722 Institutional research plan: CEZ:AV0Z10100520 Keywords : crystallographic axis orientation * Sm 1+x Ba 2-x Cu 3 O 7-$ film * RE-123 film * Cu-rich Ba-Cu-O flux * liquid epitaxy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.162, year: 2009

  6. Synthesis, vacuum ultraviolet and ultraviolet spectroscopy of Ce{sup 3+} ion doped olgite Na(Sr, Ba)PO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Huang Yanlin [School of Material Engineering, Soochow University, 178 GanJiang East Road, Suzhou, 215021 (China); Wang Xigang [School of Material Engineering, Soochow University, 178 GanJiang East Road, Suzhou, 215021 (China); Lee, Ho Sueb [Department of Physics, Changwon National University, Changwon, 641-773 (Korea, Republic of); Cho, Eunjin [Department of Physics, Changwon National University, Changwon, 641-773 (Korea, Republic of); Jang, Kiwan [Department of Physics, Changwon National University, Changwon, 641-773 (Korea, Republic of); Tao Ye [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2007-12-21

    Ce{sup 3+} ion doped olgite mineral samples, Na(Sr, Ba)PO{sub 4}, were prepared by a high temperature solid-state reaction. The sample was investigated through x-ray powder diffraction, FT-IR and FT-Raman spectra measurements. The optical properties under vacuum ultraviolet (VUV) synchrotron radiation and ultraviolet (UV) irradiation are reported for the first time. The investigated samples show a strong absorption in the VUV and UV ranges. The bands corresponding to the 4f{sup 1} {yields} 4f{sup 0}5d{sup 1} transitions of Ce{sup 3+} ions in the host lattices are identified. The barycentre of Ce{sup 3+} ions in the host lattices, the host absorption, the crystal field splitting, the emission and the Stokes shifts are presented and discussed. This Ce{sup 3+} ion doped material is a potential candidate for plasma display panel (PDP) application.

  7. Photoluminescence and Energy Transfer Properties with Y+SiO4 Substituting Ba+PO4 in Ba3Y(PO4)3:Ce(3+)/Tb(3+), Tb(3+)/Eu(3+) Phosphors for w-LEDs.

    Science.gov (United States)

    Li, Kai; Liang, Sisi; Shang, Mengmeng; Lian, Hongzhou; Lin, Jun

    2016-08-01

    A series of Ce(3+), Tb(3+), Eu(3+) doped Ba2Y2(PO4)2(SiO4) (BYSPO) phosphors were synthesized via the high-temperature solid-state reaction route. X-ray diffraction, high-resolution transmission electron microscopy, Fourier transform infrared, solid-state NMR, photoluminescence (PL) including temperature-dependent PL, and fluorescent decay measurements were conducted to characterize and analyze as-prepared samples. BYSPO was obtained by the substitution of Y+SiO4 for Ba+PO4 in Ba3Y(PO4)3 (BYPO). The red shift of PL emission from 375 to 401 nm occurs by comparing BYSPO:0.14Ce(3+) with BYPO:0.14Ce(3+) under 323 nm UV excitation. More importantly, the excitation edge can be extended from 350 to 400 nm, which makes it be excited by UV/n-UV chips (330-410 nm). Tunable emission color from blue to green can be observed under 365 nm UV excitation based on the energy transfer from Ce(3+) to Tb(3+) ions after codoping Tb(3+) into BYSPO:0.14Ce(3+). Moreover, energy transfer from Tb(3+) to Eu(3+) ions also can be found in BYSPO:Tb(3+),Eu(3+) phosphors, resulting in the tunable color from green to orange red upon 377 nm UV excitation. Energy transfer properties were demonstrated by overlap of excitation spectra, variations of emission spectra, and decay times. In addition, energy transfer mechanisms from Ce(3+) to Tb(3+) and Tb(3+) to Eu(3+) in BYSPO were also discussed in detail. Quantum yields and CIE chromatic coordinates were also presented. Generally, the results suggest their potential applications in UV/n-UV pumped LEDs. PMID:27415966

  8. Synthesis, characterization and TL response of Ce{sup 3+} activated BaMgAl{sub 10}O{sub 17} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Selot, Anupam, E-mail: selotanupam14@rediffmail.com [Department of Physics, Sadhu Vaswani College, Bhopal-462030 (India); Aynyas, Mahendra [Department of Physics, C.S.A. Govt P. G. College, Sehore-466001 (India); Tiwari, Manoj [Department of Physics, MPIET, Gondia - 441614 (India); Dev, Kapil [Department of Physics, RITS, Bhopal - 462016 (India)

    2015-06-24

    Phosphor material BaMgAl{sub 10}O{sub 17} with varying concentration of rare earth Ce{sup 3+} synthesis by combustion method at 500°C. The synthesized phosphor material characterized for their crystallinity and nature by XRD measurements. The thermoluminescecne response of phosphor exhibit TL spectra at 204°c and detailed analysis of kinetic parameter by de convoluted curve. These results show that concentration quenching occur at 5mol% of Ce dopant. The results suggest the possibility of utilizing as a phosphor may be in UV dosimeter and solid state lighting.

  9. Mixed Conduction in Tb2O3 Doped BaCeO3

    Institute of Scientific and Technical Information of China (English)

    QIU Li-Gana; MA Gui-Lin

    2006-01-01

    BaxCe0.8Tb0.2O3-α (x=0.98-1.03) solid electrolytes were synthesized and characterized by using X-ray diffraction (XRD). By using AC impedance spectroscopy and gas concentration cell electromotive force (EMF) measurements, the electrical conduction behavior of the specimens was investigated in different gases during 500-1000 ℃.The influence of nonstoichiometry in the specimens with x≠ 1 on conduction properties was studied and comparedwith that in the specimen with x= 1. The results show that the specimens are all of perovskite-type orthorhombic structure. In 500-1000 ℃, electronic hole conduction is dominant in dry and wet oxygen, air or nitrogen. Protonic conduction is dominant in wet hydrogen and it is about two orders of magnitude higher than that in hydrogen-free atmospheres (oxygen, air and nitrogen). The electrical conductivity of the same specimen in water apor-saturated oxygen, air or nitrogen is slightly higher than that in corresponding gas without water vapor. The electrical conductivities of the nonstoichiometric specimens are higher than those of the stoichiometric one.

  10. Microwave dielectric properties and microstructure of Ba2-xSm4+2x/3Ti8+yO24+2y ceramics

    International Nuclear Information System (INIS)

    The microstructure and microwave dielectric properties of barium samarium titanium oxide Ba2-xSm4+2x/3Ti8+yO24+2y (x=0.1, y=0∼2) ceramics (BST) were investigated. The optimum compositions of BST ceramics were synthesized and discussed base on the structure formula of the tungsten-bronze-type crystal phase. Differential thermal analysis (DTA) was used to select the suitable sintering temperatures. The relative dielectric constant of the BST compositions saturated in a range from 63 to 85. Qxf values of 8500-13000 (GHz) were obtained for various y values in dense samples. The temperature coefficient of resonant frequency τf was adjusted from a negative -12 ppm per deg. C value to a positive value 17 ppm per deg. C. X-ray diffraction, SEM and EDS analysis were used to investigate the microstructure and correlate its relationship with microwave dielectric properties of BST ceramics

  11. Charge/orbital ordering structure in ordered perovskite Sm sub 1 sub / sub 2 Ba sub 1 sub / sub 2 MnO sub 3

    CERN Document Server

    Uchida, M; Akahoshi, D; Kumai, R; Tomioka, Y; Tokura, Y; Arima, T H

    2002-01-01

    In an A-site ordered perovskite manganite Sm sub 1 sub / sub 2 Ba sub 1 sub / sub 2 MnO sub 3 , a new charge/orbital ordering pattern was found at room temperature. Electron diffraction studies revealed a series of superlattice reflections with modulation vectors at q sub 2 =(1/2, 1/2, 1/2) as well as at q sub 1 =(1/4, 1/4, 0) in the tetragonal setting (a sub p x a sub p x 2a sub p , a sub p being the cubic perovskite lattice parameter). Together with the results of the resonant X-ray scattering and the charge-transport and magnetization measurements, a new model for the three-dimensional charge/orbital ordering in the ordered perovskite is proposed. (author)

  12. Crystal structure and magnetic properties of R{sub 3}Co{sub 0.5}GeS{sub 7} (R = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm) and R{sub 3}Ni{sub 0.5}GeS{sub 7} (R = Y, Ce, Sm, Gd, Tb, Dy, Ho, Er and Tm)

    Energy Technology Data Exchange (ETDEWEB)

    Daszkiewicz, M. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław (Poland); Pashynska, Yu.O. [Department of Material Science, Lutsk National Technical University, L' vivska str. 75, 43018 Lutsk (Ukraine); Marchuk, O.V. [Department of Inorganic and Physical Chemistry, Eastern European National University, Voli Ave 13, 43009 Lutsk (Ukraine); Gulay, L.D. [Department of Ecology and Protection of Environment, Eastern European National University, Voli Ave 13, 43009 Lutsk (Ukraine); Kaczorowski, D., E-mail: D.Kaczorowski@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław (Poland)

    2015-10-25

    The crystal structure of quaternary compounds R{sub 3}Co{sub 0.5}GeS{sub 7} (R = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm) and R{sub 3}Ni{sub 0.5}GeS{sub 7} (R = Y, Ce, Sm, Gd, Tb, Dy, Ho, Er and Tm) (La{sub 3}Mn{sub 0.5}SiS{sub 7} structure type, space group P6{sub 3}, Pearson symbol hP23) was determined by means of X-ray single crystal diffraction. The R atoms are located in trigonal prisms with two additional atoms, the Co (Ni) atoms occupy octahedra, the Ge atoms are located in tetrahedra. Magnetic properties of the compounds R{sub 3}Co{sub 0.5}GeS{sub 7} (R = Sm and Gd) and R{sub 3}Ni{sub 0.5}GeS{sub 7} (R = Gd, Dy, Er and Tm) were studied down to 1.72 K. Their magnetic behaviour is governed by trivalent rare-earth and divalent transition-metal constituents. In each material, the magnetic exchange interactions are dominated by antiferromagnetic correlations, which promote long-range magnetic orderings at low temperatures. - Highlights: • Identification of several novel R3Co0.5GeS7 and R3Ni0.5GeS7 compounds. • Refinement of their crystal structures from single crystal XRD data. • Determination of magnetic behaviour in a few representative phases.

  13. Superconductivity and mechanical properties of SmBa2Cu3O7-δ added with nano-crystalline ZnFe2O4

    Science.gov (United States)

    Abdeen, W.; El Tahan, A.; Awad, R.; Abou Aly, A. I.; El-Maghraby, E. M.; Khalaf, A.

    2016-06-01

    The effect of nanosized ZnFe2O4 addition on the physical properties of polycrystalline SmBa2Cu3O7-δ superconductor was studied. Superconducting samples of the type (ZnFe2O4) x SmBa2Cu3O7-δ, x = 0.00, 0.01, 0.02, 0.04, 0.06, 0.08, 0.10, 0.15 and 0.20 wt% were prepared by the solid-state reaction method. The characterization and superconductivity investigation were carried out using X-ray powder diffraction, XRD, scanning electron microscope, SEM, energy-dispersive X-ray, EDX, dc electrical resistivity and transport critical current density at 77 K. Improvements in the volume fraction, superconducting transition temperature, Tc, and transport critical current density, Jc, were observed as x increased from 0.00 up to 0.08 wt% and then they decreased with further increase in nanosized ZnFe2O4 addition. The Vickers microhardness number, H v, and elastic parameters have been measured at room temperature. The ultrasonic pulse-echo technique at 4 MHz was used to determine the elastic parameters. H v and the elastic parameters were observed to increase with increasing x. The enhancement of the elastic parameters may be due to the hindrance of dislocation motion with nanosized ZnFe2O4 addition. Moreover, Debye temperatures ( θ D) were calculated and it was found that their values increased with increasing nanosized ZnFe2O4 addition. The elastic parameters of the samples were computed and corrected to zero porosity using different models. Finally, the relationship between Young's modulus and H v was estimated for different models.

  14. Synthesis and characterization of BaCe0.8Y0.2O2.9 nanopowder by sol-gel auto-ignited method

    International Nuclear Information System (INIS)

    A sol-gel auto-ignited synthesis, which is a hybrid of sol-gel and auto-ignited techniques, was applied to preparation of homogeneous and stoichiometric BaCe0.8Y0.2O2.9 nanocrystalline ceramic powder as solid electrolyte used in solid oxide fuel cells at 1000 C. Optimal pH value for the mixed citrate-nitrate solutions was determined by calculation. The DTA-TG and XRD were used to investigate the thermal decomposition of the gel precursor. The structure and phase present of the nanocrystalline BaCe0.8Y0.2O2.9 powders were characterized by XRD, BET and SEM techniques. (orig.)

  15. (d,p) reactions on 124Sn, 130Te, 138Ba, 140Ce, 142Nd, and 208Pb below and near the Coulomb barrier

    International Nuclear Information System (INIS)

    The reactions 124Sn(d,p)125Sn, 130Te(d,p)131Te, 138Ba(d,p)139Ba, 140Ce(d,p)141Ce, 142Nd(d,p)143Nd, and 208Pb(d,p)209Pb have been investigated by measuring the differential cross sections of the (d,p) reactions and of the elastic scattering of deuterons at various incident energies below and near the Coulomb barrier. Using scattering potentials which describe the elastic scattering of the particles in the entrance and exit channels, reduced normalizations of 40 final states have been determined which are nearly independent of the uncertainties due to the ambiguities of optical potentials. The experimental errors are 8% on the average. In the energy region studied the expected constancy of derived spectroscopic factors is demonstrated

  16. Preparation and third-order nonlinear optical properties of self-organized complex oxide Ce: BaTiO3 quantum dots

    Institute of Scientific and Technical Information of China (English)

    师文生; 陈正豪; 刘宁宁; 吕惠宾; 周岳亮; 崔大复; 杨国桢

    2000-01-01

    Pulsed laser ablation epitaxial Strancky-Krastanow growth of self-organized complex oxide Ce:BaTiO3 quantum dots on MgO(100) substrates is demonstrated. Atomic force microscopy and X-ray diffraction are used to observe the structure and the growth process of the self-organized complex oxide quantum dots. The average dimension, height, and the density of self-organized complex oxide Ce:BaTiO3 quantum dots are given. The nonlinear refractive indexes of the wetting layer and the self-organized ordered quantum dots are determined by the single beam Z-scan method. The mechanisms of the nonlinear effect enhancement for these low-dimensional structure are discussed.

  17. Preparation and third-order nonlinear optical properties of self-organized complex oxide Ce:BaTiO3 quantum dots

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Pulsed laser ablation epitaxial Strancky-Krastanow growth of self-organized complex oxide Ce:BaTiO3 quantum dots on MgO(100) substrates is demonstrated.Atomic force microscopy and X-ray diffraction are used to observe the structure and the growth process of the self-organized complex oxide quantum dots.The average dimension,height,and the density of self-organized complex oxide Ce:BaTiO3 quantum dots are given.The nonlinear refractive indexes of the wetting layer and the self-organized ordered quantum dots are determined by the single beam Z-scan method.The mechanisms of the nonlinear effect enhancement for these low-dimensional structure are discussed.

  18. Hole-doping effect on the Verwey-type transition and magnetoresistivity of Ba(Sm,Ca)Fe 2O 5+ δ

    Science.gov (United States)

    Nakamura, J.; Lindén, J.; Yamauchi, H.; Karppinen, M.

    2002-02-01

    Two series of samples of the oxygen-deficient double-perovskite phase, Ba(Sm,Ca)Fe 2O 5+ δ were synthesized employing a sample encapsulation technique that utilizes Fe metal as an oxygen getter. The hole-doping level on the FeO 2 plane was controlled by varying the amount of excess oxygen or the Ca concentration at the Sm site. Earlier it had been found that at room temperature five-coordinated Fe 2+ and Fe 3+ species form pairs by sharing a d electron, leading to the formation of a Fe 2.5+ fluctuating valence state [Phys. Rev. B 60 (1999) 15,251]. At TV, a Verwey-type transition occurred, signifying the charge separation of the Fe 2.5+ fluctuating valence state into high-spin Fe 2+ and Fe 3+. Moreover, related to the Verwey-type transition a negative magnetoresistance peak with a magnitude of a few percent was observed [Appl. Phys. Lett. 77 (2000) 1683]. The position of the peak was found to correspond to the jumps seen in the susceptibility and resistivity vs. temperature curves. For the present samples, it is found that the value of TV is severely decreased upon increasing the Ca concentration, as seen by susceptibility and magnetoresistivity measurements. Introduction of excess oxygen leads to a less severe decrease of the transition temperature. The observed behavior of TV was reproduced by a simple model based on combinatorial-entropy calculations.

  19. Cu and Gd co-doped BaCeO3 proton conductors: Experimental vs SEM image algorithmic-segmentation results

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Novel algorithmic evaluation method of image resolution using SEM data. • Microstructure description and electrical conductivity evaluation via algorithmic segmentation of SEM images. • The method permits to divide the volume resistance and grain-boundary resistance at any temperature range. • Total conductivity and mean grain size of the ceramics as a function of Cu content. - Abstract: Segmentation algorithms for the quantitative description of the surface microstructure and the evaluation of the grain-boundary conductivity of ceramic materials surface using SEM microphotographs analysis was developed and applied in the present work for first time in barium cerate based solid solutions. To this purpose novel polycrystalline ceramic materials based on Cu and Gd co-doped BaCeO3 proton conductors exhibiting high proton conductivity have been prepared and characterized. The influence of copper oxide as a dopant on the microstructure and the electrical properties of BaCe0.9–xGd0.1CuxO3–δ (0≤x≤0.1) have been examined in detail. It is shown that the dependence of the electrical conductivity is correlated with the average oxide grain diameter variation in air at various temperatures. Moreover, it was found that the algorithmic segmentation evaluation results are in good agreement with the experimental ones, verifying the considerable contribution of the grain-boundary conductivity to the electrical transport of Cu and Gd co-doped BaCeO3 proton conductors

  20. Investigation into the Incorporation of Phosphate into BaCe1−yAyO3−y/2 (A = Y, Yb, In

    Directory of Open Access Journals (Sweden)

    Alaric D. Smith

    2014-01-01

    Full Text Available In this paper we examine the effect of doping phosphate into BaCe1−yAyO3−y/2 (A = Y, Yb, In. The samples were analysed through a combination of X-ray diffraction, TGA, Raman spectroscopy and conductivity measurements. The results showed that phosphate could be incorporated into this system up to the 10% doping level, although this required an increased Y/Yb/In content, e.g., BaCe0.6(Y/In/Yb0.3P0.1O2.9. The phosphate doping was, however, shown to lead to a decrease in conductivity; although at low phosphate levels high conductivities were still observed, e.g., for BaCe0.65Y0.3P0.05O2.875, σ = 4.3 × 10−3 S cm−1 at 600 °C in wet N2. In terms of the effect of phosphate incorporation on the CO2 stability, it was shown to lead to a small improvement for the In containing samples, whereas the yttrium doped compositions showed no change in CO2 stability.

  1. Study of the Electrodynamic Response of SmBa2Cu3O7-δ Thin Films in the Microwave Region

    Science.gov (United States)

    Lamura, G.; di Gennaro, E.; Andreone, A.; Boffa, M.; Cucolo, A. M.

    We present some experimental results on the temperature dependence of the surface resistance Rs and magnetic penetration depth λ of thin films of SmBa2Cu3O7-δ. The samples, 0.25 μm thick, were grown by a dc sputtering technique on (100) K LaAlO3 single crystal substrates, with critical temperatures ranging between 87 and 88 K Accurate measurements af the surface impedance Zs were performed down to 4 K by means of a dielectrically loaded cavity operating in the microwave region (20 GHz). Both λ and Rs show a monotonic temperature behavior, with no evidence of low temperature up-turn characteristic of other rare earth based cuprates like GdBa2Cu3O7-δ. At low temperatures, we observed am almost linear behavior of λ with a slope of ~ 0.3 nm/K up to 25 K, as expected in a d-wave pairing scenario. The real part of complex conductivity σ1, shows a bump at around 40 K, in agreement with previous reports.

  2. The crystal structures of R{sub 3}CuGeS{sub 7} (R = Ce-Nd, Sm, Gd-Dy and Er)

    Energy Technology Data Exchange (ETDEWEB)

    Gulay, L.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Lychmanyuk, O.S. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Wolcyrz, M. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland)]. E-mail: M.Wolcyrz@int.pan.wroc.pl; Pietraszko, A. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine)

    2006-11-30

    Crystal structures of R{sub 3}CuGeS{sub 7} (R = Ce, Pr, Nd, Sm, Gd, Tb, Dy and Er) (La{sub 3}CuSiS{sub 7} structure type, space group P6{sub 3}, Pearson symbol hP24) were determined by means of X-ray single crystal diffraction (a = 1.0225(1) nm, c = 0.58350(7) nm, R {sub 1} = 0.0213 for Ce{sub 3}CuGeS{sub 7}; a = 1.0168(1) nm, c 0.58223(7) nm, R {sub 1} = 0.0284 for Pr{sub 3}CuGeS{sub 7}; a = 1.0123(1) nm, c 0.57942(7) nm, R {sub 1} = 0.0240 for Nd{sub 3}CuGeS{sub 7}) and X-ray powder diffraction (a = 1.00144(1) nm, c = 0.57714(1) nm, R {sub Bragg} = 0.0968 for Sm{sub 3}CuGeS{sub 7}; a = 0.99428(1) nm, c = 0.57592(1) nm, R {sub Bragg} = 0.0863 for Gd{sub 3}CuGeS{sub 7}; a = 0.98863(1) nm, c = 0.57535(1) nm, R {sub Bragg} = 0.0838 for Tb{sub 3}CuGeS{sub 7}; a = 0.98371(3) nm, c = 0.57552(3) nm, R {sub Bragg} = 0.0802 for Dy{sub 3}CuGeS{sub 7}; a = 0.97415(1) nm, c = 0.57835(1) nm, R {sub Bragg} = 0.0709 for Er{sub 3}CuGeS{sub 7}). The structures are built up from three-dimensional network of RS{sub 8} distorted square antiprisms sharing edges, consolidated by GeS{sub 4} tetrahedra and CuS{sub 3} triangles sharing edges with the antiprisms.

  3. Fractal and agglomeration behavior in Gd and Sm doped CeO2 nano-crystalline powders

    International Nuclear Information System (INIS)

    Nanocrystalline Gd, Sm doped ceria powders were synthesized by a combustion technique, using glycine as the fuel. These powders, after calcination at 600 oC, were characterized by powder X-ray diffraction and were found to be phase pure. The crystallite sizes, as calculated from X-ray line broadening were in the range of 11-13 nm, which were in close agreement with those obtained from the SAXS studies. The TEM studies also showed the particle sizes to be in the range of 10-15 nm. These powders showed a high surface area as observed from BET technique. The extent and nature of agglomeration was studied by a particle size analyzer. The fractal behaviour of these nano-sized powders prepared by combustion synthesis, has also been investigated by small angle X-ray scattering technique. Results showed that the powders contain aggregates with rough fractal surfaces above a length scale of 20 nm. These parameters of the powders and their agglomerates were found to play a significant role in the sintering behavior

  4. Improvement in Jc performance below liquid nitrogen temperature for SmBa2Cu3Oy superconducting films with BaHfO3 nano-rods controlled by low-temperature growth

    International Nuclear Information System (INIS)

    For use in high-magnetic-field coil-based applications, the critical current density (Jc) of REBa2Cu3Oy (REBCO, where RE = rare earth) coated conductors must be isotropically improved, with respect to the direction of the magnetic field; these improvements must be realized at the operating conditions of these applications. In this study, improvement of the Jc for various applied directions of magnetic field was achieved by controlling the morphology of the BaHfO3 (BHO) nano-rods in a SmBCO film. We fabricated the 3.0 vol. % BHO-doped SmBCO film at a low growth temperature of 720 °C, by using a seed layer technique (Ts = 720 °C film). The low-temperature growth resulted in a morphological change in the BHO nano-rods. In fact, a high number density of (3.1 ± 0.1) × 103 μm−2 of small (diameter: 4 ± 1 nm), discontinuous nano-rods that grew in various directions, was obtained. In Jc measurements, the Jc of the Ts = 720 °C film in all directions of the applied magnetic field was higher than that of the non-doped SmBCO film. The Jcmin (6.4 MA/cm2) of the former was more than 6 times higher than that (1.0 MA/cm2) of the latter at 40 K, under 3 T. The aforementioned results indicated that the discontinuous BHO nano-rods, which occurred with a high number density, exerted a 3D-like flux pinning at the measurement conditions considered. Moreover, at 4.2 K and under 17 T, a flux pinning force density of 1.6 TN/m3 was realized; this value was comparable to the highest value recorded, to date

  5. Improvement in Jc performance below liquid nitrogen temperature for SmBa2Cu3Oy superconducting films with BaHfO3 nano-rods controlled by low-temperature growth

    Directory of Open Access Journals (Sweden)

    S. Miura

    2016-01-01

    Full Text Available For use in high-magnetic-field coil-based applications, the critical current density (Jc of REBa2Cu3Oy (REBCO, where RE = rare earth coated conductors must be isotropically improved, with respect to the direction of the magnetic field; these improvements must be realized at the operating conditions of these applications. In this study, improvement of the Jc for various applied directions of magnetic field was achieved by controlling the morphology of the BaHfO3 (BHO nano-rods in a SmBCO film. We fabricated the 3.0 vol. % BHO-doped SmBCO film at a low growth temperature of 720 °C, by using a seed layer technique (Ts = 720 °C film. The low-temperature growth resulted in a morphological change in the BHO nano-rods. In fact, a high number density of (3.1 ± 0.1 × 103 μm−2 of small (diameter: 4 ± 1 nm, discontinuous nano-rods that grew in various directions, was obtained. In Jc measurements, the Jc of the Ts = 720 °C film in all directions of the applied magnetic field was higher than that of the non-doped SmBCO film. The Jcmin (6.4 MA/cm2 of the former was more than 6 times higher than that (1.0 MA/cm2 of the latter at 40 K, under 3 T. The aforementioned results indicated that the discontinuous BHO nano-rods, which occurred with a high number density, exerted a 3D-like flux pinning at the measurement conditions considered. Moreover, at 4.2 K and under 17 T, a flux pinning force density of 1.6 TN/m3 was realized; this value was comparable to the highest value recorded, to date.

  6. Yttrium doped BaCeO3 thin films by spray pyrolysis technique for application in solid oxide fuel cell

    International Nuclear Information System (INIS)

    Highlights: • BCY20 thin electrolyte was deposited by economical spray pyrolysis technique. • Solution concentration and annealing temperature affects structure and morphology. • Excellent agreement with XRD data of lattice parameter. • The dc conductivity in argon at 600 °C was 4.25 × 10−3 S cm−1. -- Abstract: Yttrium doped barium cerate (BCY) a solid state ion conductor which exhibits proton conductivity under proper atmospheric conditions, is used as an electrolyte in a solid oxide fuel cell (SOFCs). In present work, nanocrystalline BaCe0.8Y0.2O2.9 (BCY20) thin films were successfully deposited onto alumina substrates by simple and economical spray pyrolysis technique (SPT) at 250 °C. The effect of solution concentration and annealing on physico-chemical properties of BCY20 thin film has been studied. The X-ray diffraction (XRD) studies of spray pyrolysed BCY20 films revealed polycrystalline (crystallite size 35 nm) orthorhombic structure with lattice parameters a = 8.77 Å, b = 6.234 Å and c = 6.223 Å. The scanning electron micrographs showed dense morphology which is very useful for electrolyte. The stoichiometry was confirmed by elemental analysis and the estimated atomic ratio was in good agreement with that of the precursor solution ratio. The most intense band at 353.26 cm−1 observed in room temperature Raman spectrum of BCY20 film was due to vibrational mode of barium cerate. The FTIR spectra with heat treatment shows no carbon based vibration bonds, revealing absence of carbon based surface impurities in the sample. The dc conductivities measured in air and argon atmospheres at 600 °C were 1.7 × 10−3 and 4.25 × 10−3 S cm−1, respectively

  7. A new family of Ce-doped SmFeO3 perovskite for application in symmetrical solid oxide fuel cells

    Science.gov (United States)

    Fan, Weiwei; Sun, Zhu; Wang, Junkai; Zhou, Jun; Wu, Kai; Cheng, Yonghong

    2016-04-01

    Here, a nanoporous Sm0.95Ce0.05FeO3-δ (SCFO) perovskite-type oxide is assessed in regard to its possible use as an electrode material for symmetrical solid oxide fuel cells. It is found that SCFO has a good redox stability after characterizing the sample which is calcined at 850 °C in 5% H2/N2 for 10 h. Optimized electrochemical performances are obtained in both the nanoporous anode and cathode which are mainly due to the high catalytic activity of SCFO for redox reaction. The peak power density of SCFO|YSZ|SCFO symmetrical cell is as high as 130 mW cm-2 at 800 °C using pure, humidified H2 as the fuel. Moreover, the maximum power density of 193 mW cm-2 can be obtained for the SCFO:YSZ(7:3)|YSZ|SCFO:YSZ(7:3) symmetrical cell under the same conditions.

  8. Determination of the upper critical field of the electron-doped superconductor Sm1.85Ce0.15CuO4-y from resistive fluctuations

    International Nuclear Information System (INIS)

    The upper critical field Hc2(T) for the magnetic field applied parallel to the c axis of a Sm1.85Ce0.15CuO4-y single crystal has been determined from an analysis of magnetoresistance data in terms of the Ginzburg-Landau fluctuation theory for layered superconductors. The fluctuations are predominantly two dimensions (2D) away from Tc(H) with a crossover to 3D as Tc(H) is approached. The Hc2(T) curve shows negative curvature and is in excellent agreement with the Werthamer, Helfand, Hohenberg, and Maki theory for conventional superconductors without paramagnetic limiting effects. The values of the initial slope (dHc2/dT)Tc=-7.38 kOe/K, coherence length ξ(0)=48.4 A, and orbital critical field Hc2(0)=97.6 kOe, derived from this analysis, are in good agreement with the values we previously obtained from fits of the Hao-Clem variational model to reversible magnetization data below Tc

  9. A robust NiO-Sm0.2Ce0.8O1.9 anode for direct-methane solid oxide fuel cell

    KAUST Repository

    Tian, Dong

    2015-07-02

    In order to directly use methane without a reforming process, NiO-Sm0.2Ce0.8O1.9 (NiO-SDC) nanocomposite anode are successfully synthesized via a one-pot, surfactant-assisted co-assembly approach for direct-methane solid oxide fuel cells. Both NiO with cubic phase and SDC with fluorite phase are obtained at 550 °C. Both NiO nanoparticles and SDC nanoparticles are highly monodispersed in size with nearly spherical shapes. Based on the as-synthesized NiO-SDC, two kinds of single cells with different micro/macro-porous structure are successfully fabricated. As a result, the cell performance was improved by 40%-45% with the new double-pore NiO-SDC anode relative to the cell performance with the conventional NiO-SDC anode due to a wider triple-phase-boundary (TPB) area. In addition, no significant degradation of the cell performance was observed after 60 hours, which means an increasing of long term stability. Therefore, the as-synthesized NiO-SDC nanocomposite is a promising anode for direct-methane solid oxide fuel cells.

  10. Effects of laminating and co-firing conditions on the performance of anode-supported Ce0.8Sm0.201.9 film electrolyte

    Directory of Open Access Journals (Sweden)

    Li X.

    2011-01-01

    Full Text Available In order to evaluate the laminating and co-firing technique on the performance of anode-supported Ce0.8Sm0.2O1.9 (SDC film electrolyte and its single cell, NiO-YSZ and NiOSDC anode-supported SDC film electrolytes were fabricated by laminating 24 sheets of anode plus one sheet of electrolyte and co-firing. La0.4Sr0.6Co0.2Fe0.8O3-δ (LSCF-SDC cathode was coated on the SDC electrolytes to form a single cell. The lamination was tried at different laminating temperatures and pressures and the co-firing was carried out at different temperatures. The results showed that the laminating temperature should above the glass transition temperature (Tg of the binder. The laminating pressure of 70 MPa resulted in warp of the samples. The best co-firing temperature of the anode-supported SDC film electrolyte was 1400°C. The SDC film electrolyte formed well adherence to the anode. The NiO-YSZ anode had larger flexural strength than the NiO-SDC anode. The NiO-YSZ anode-supported SDC film electrolyte single cell had an open circuit voltage of 0.803 V and a maximum power density of 93.03 mW/cm2 with hydrogen as fuel at 800°C.

  11. Thermochemical Properties of the Complexes RE(HSal)3·2H2O (RE=La, Ce, Pr, Nd, Sm)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Five solid rare earth salicylate complexes were synthesized by low hydrated lathanide chloride and salicylic acid. The complexes in this experiment were identified as the general formula RE(Hsal)3·2H2O(RE=La, Ce, Pr, Nd, Sm) by elemental analysis and EDTA volumetric analysis. IR spectra of the complexes show that carboxyl of salicylic acid coordinates to RE3+ ions. Electrochemical behaviors of the complexes on the glass-carbon electrode were researched with cyclic voltammetry (CV). It is indicated that the electrochemical process of the complexes is a one-electron redox process and the electrochemical reversibility of complexes is less than that of the lanthanide chlorides. The constant-volume combustion energies of complexes, ΔcU, were determined with a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, ΔcHθm, and standard molar enthalpies of formation, ΔfHθm, were calculated.

  12. The pressure effect on crystal structure of complex ferroelectrics Ba{sub 4}Sm{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30} and Ba{sub 4}Gd{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30}

    Energy Technology Data Exchange (ETDEWEB)

    Jabarov, Sakin H. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Azerbaijan National Academy of Sciences, Baku (Azerbaijan). Inst. of Physics; Kichanov, Sergey E. [Joint Institute for Nuclear Research, Dubna (Russian Federation). Frank Lab of Neutron Physics; Kozlenko, Denis P.; Lukin, Evgeniy V.; Savenko, Boris N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Mehdiyeva, Rafiga Z.; Mammadov, Ali I. [Azerbaijan National Academy of Sciences, Baku (Azerbaijan). Inst. of Physics; Lathe, Christian [Helmholtz Centre Potsdam (Germany). German Research Centre for Geosciences

    2014-07-01

    The crystal structure of complex oxide ferroelectrics Ba{sub 4}Sm{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30} and Ba{sub 4}Gd{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30} have been studied by means of energy-dispersive X-ray diffraction method at high pressure up to 4 GPa at room temperature. At ambient pressure, the crystal structure of both compounds is described by the tetragonal symmetry with space group P4/mbm. At pressure P∝1.8 GPa in Ba{sub 4}Sm{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30} and at P∝2.2 GPa in Ba{sub 4}Gd{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30} the structure phase transition have been observed. The orthorhombic structure model with Pba2 space group for high-pressure phase of those compounds have been proposed. The baric dependences of lattice parameters and unit cell volumes of Ba{sub 4}Sm{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30} and Ba{sub 4}Gd{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30} compounds have been obtained.

  13. Photoluminescence spectra of thenardite Na{sub 2}SO{sub 4} activated with rare-earth ions, Ce{sup 3+}, Sm{sup 3+}, Tb{sup 3+}, Dy{sup 3+} and Tm{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Sidike, Aierken [School of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi, 830054 Xinjiang (China); Saliqur, Rahman Abu Zayed Mohammad [Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka, Kita-ku, 700-8530 Okayama (Japan); He Juiyang [Graduate School of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi, 830054 Xinjiang (China); Gong Lanxin [School of Life Science and Chemistry, Xinjiang Normal University, Urumqi, 830054 Xinjiang (China); Atobe, K. [Department of Physics, Faculty of Education, Okayama University, Tsushima-naka, Kita-ku, 700-8530 Okayama (Japan); Yamashita, N., E-mail: yosiko3@io.ocn.ne.jp [Department of Physics, Faculty of Education, Okayama University, Tsushima-naka, Kita-ku, 700-8530 Okayama (Japan)

    2011-09-15

    Five Na{sub 2}SO{sub 4}:RE{sup 3+} phosphors activated with rare-earth (RE) ions (RE{sup 3+}=Ce{sup 3+}, Sm{sup 3+}, Tb{sup 3+}, Dy{sup 3+} and Tm{sup 3+}) were synthesized by heating natural thenardite Na{sub 2}SO{sub 4} from Ai-Ding Salt Lake, Xinjiang, China with small amounts of rare-earth fluorides, CeF{sub 3}, SmF{sub 3}, TbF{sub 3}, DyF{sub 3} and TmF{sub 3}, at 920 {sup o}C in air. The photoluminescence (PL) and optical excitation spectra of the obtained phosphors were measured at 300 and 10 K. In the PL spectrum of Na{sub 2}SO{sub 4}:Ce{sup 3+} at 300 K, two overlapping bands with peaks at 335 and 356 nm due to Ce{sup 3+} were first observed. Narrow bands observed in PL and excitation spectra of Na{sub 2}SO{sub 4}:RE{sup 3+} (RE{sup 3+}=Sm{sup 3+}, Tb{sup 3+}, Dy{sup 3+} and Tm{sup 3+}) phosphors were well identified with the electronic transitions within the 4f{sup n} (n=5, 8, 9 and 12) configurations of RE{sup 3+}. The existence of excitation bands with high luminescence efficiency at wavelengths shorter than 230 nm is characteristic of Na{sub 2}SO{sub 4}:RE{sup 3+} (RE{sup 3+}=Sm{sup 3+}, Tb{sup 3+}, Dy{sup 3+} and Tm{sup 3+}) phosphors. The obtained results suggest that these phosphors are unfavorable as the phosphor for usual fluorescence tubes, i.e., mercury discharge tubes, but may be favorable as the phosphor for UV-LED fluorescent tubes and as cathodoluminescence, X-ray luminescence and thermoluminescence phosphors. - Highlights: > Five Na{sub 2}SO{sub 4}:RE{sup 3+} (RE{sup 3+}=Ce{sup 3+}, Sm{sup 3+}, Tb{sup 3+}, Dy{sup 3+} and Tm{sup 3+}) phosphors were synthesized by heating natural thenardite. > The emission and excitation spectra of the obtained phosphors were measured at 300 and 10 K. > In Na{sub 2}SO{sub 4}:Ce{sup 3+} at 300 K, two overlapping emission bands with peaks at 335 and 356 nm were first observed.

  14. Influence of Zr and Ce doping on electromagnetic properties of (Gd,Y)-Ba-Cu-O superconducting tapes fabricated by metal organic chemical vapor deposition

    International Nuclear Information System (INIS)

    (Gd,Y)Ba2Cu3Ox tapes have been fabricated by metal organic chemical vapor deposition (MOCVD) with Zr-doping levels of 0-15 mol.% and Ce doping levels of 0-10 mol.% in 0.4 μm thick films. The critical current density (Jc) of Zr-doped samples at 77 K, 1 T applied in the orientation of H -parallel c is found to increase with Zr content and shows a maximum at 7.5% Zr doping. The 7.5% Zr-doped sample exhibits a critical current density (Jc) of 0.95 MA/cm2 at H -parallel c which is more than 70% higher than the Jc of the undoped sample. The peak in Jc at H -parallel c is 83% of that at H -parallel a-b in the 7.5% Zr-doped sample which is more than twice as that in the undoped sample. Superconducting transition temperature (Tc) values as high as about 89 K have been achieved in samples even with 15% Zr and 10% Ce. Ce-doped samples with and without Ba compensation are found to exhibit substantially different Jc values as well as angular dependence characteristics.

  15. Sm2+ fluorescence and absorption in cubic BaCl2: Strong thermal crossover of fluorescence between 4f6 and 4f55d1 configurations

    International Nuclear Information System (INIS)

    The optical absorption and fluorescence spectra of polycrystalline cubic-phase barium chloride doped with divalent samarium is reported. X-ray diffraction shows that the cubic phase is stabilised at room temperature by the addition of 12.5% lanthanum trichloride; no evidence for the more common orthorhombic or hexagonal phases of barium chloride is found. Optical absorption measurements are in good agreement with a calculated spectrum for Sm2+ ions at a single site of cubic symmetry, even though the material must contain a substantial fraction of chlorine interstitials and lanthanum substitutional ions. The photoluminescence spectrum shows sharp red line emission from the 5D1 and 5D0 levels of the 4f6 configuration, again consistent with a single site of cubic symmetry, together with a broad emission, also in the red, which arises from the lowest levels of the 4f55d1 configuration. The relative strengths of these emissions are strongly temperature dependent; at room temperature the broad band from the lowest 4f55d1 levels peaking at 15,130 cm−1 is dominant, while at low temperature (∼12 K) sharp lines from the 5D0 level dominate. The most intense line corresponds to the 5D0→7F1 transition at 14,300 cm−1, but the nominally forbidden 5D0→7F0 transition also has significant intensity. The marked temperature dependence of the intensity of the lines and bands is successfully modelled by rate equations and is explained on the basis of thermally activated crossovers between the 4f6 (5D0,1) levels and the lowest levels of the 4f55d1 configuration; it is necessary to include the three lowest levels of the 4f55d1 configuration sandwiched between the 5D0 and 5D1 levels. - Highlights: ► Strong red 5d emission matched to semiconductor-based radiation detectors. ► Stabilisation of the high temperature cubic phase of Sm-doped BaCl2 at 295 K. ► Dramatic temperature-induced intensity transfer between 5d and 4f PL emissions. ► Most comprehensive model yet achieved

  16. Synthesis and photoluminescence of Sm3+ doped alkali alkaline earth borate hosts NaBa4 (BO3)3 and LiSr4(BO3)3

    International Nuclear Information System (INIS)

    In this paper we report the photoluminescence of Sm3+ doped alkali alkaline borate hosts NaBa4 (BO3)3 and LiSr4 (BO3)3. For the synthesis of alkali alkaline borate hosts NaBa4 (BO3)3 and LiSr4 (BO3)3 doped with different concentrations of Sm3+ ions, we used the novel combustion technique. The phase purity of the hosts was confirmed by the powder XRD technique. The photoluminescence of the phosphors were carried out within 300 to 700 nm wavelength range. The phosphor shows intense orange red (602 nm) emission for near UV excitation. The FTIR spectra of the phase pure hosts have also been reported. (author)

  17. First-principles study of structural, electronic, magnetic and thermodynamic properties of the double perovskite Ba2CeCoO6

    Science.gov (United States)

    Xie, Huan-Huan; Gao, Qiang; Li, Lei; Lei, Gang; Hu, Xian-Ru; Deng, Jian-Bo

    2016-07-01

    The structural, electronic and magnetic properties of cubic double perovskite Ba2CeCoO6 were calculated using first-principles full-potential local-orbital minimum-basis method. This compound has a cubic crystal structure with space group Fm 3 bar m. By analysing the band structure we found, at the equilibrium lattice constant, this compound is a half-metal. Moreover, the half-metallicity can be kept under a large range of pressure. Meanwhile, the thermodynamic characters are investigated using the quasi-harmonic Debye model.

  18. Thermoelastic and structural properties of ionically conducting cerate perovskites: (I) BaCeO3 at low temperature in the Pbnm phase

    DEFF Research Database (Denmark)

    Knight, Kevin S.; Bonanos, Nikolaos

    2013-01-01

    The thermoelastic and structural properties of BaCeO3 perovskite in the Pbnm phase field have been studied using high resolution neutron diffractometry at 37 temperatures between 2 K and 350 K. From a simultaneous fit of the isochoric heat capacity and unit cell volume, the vibrational density of...... parameter. Structural parameters are presented as the amplitudes of the seven symmetry-adapted basis-vectors of the aristotype phase, and a structural basis for the temperature-dependence of the bond lengths is outlined. The critical exponent associated with the temperature variation of the primary order...

  19. Structural, magnetic and magnetotransport properties of La0.7-CeBa0.3MnO3 ( = 0.0-0.4)

    Indian Academy of Sciences (India)

    R Vengadesh Kumara Mangalam; A Sundaresan

    2006-01-01

    Structural, magnetic and magnetotransport properties of La0.7-CeBa0.3MnO3 ( = 0-0.4) have been investigated although some unreacted secondary phases of CeO2 were present. The rhombohedral structure (-3) for = 0 transforms to orthorhombic with the space group Imma for = 0.3. All samples showed ferromagnetic transition above 300 K and a negative magnetoresistance. For > 0.1, magnetization data measured at 1 T showed a decrease at low temperatures ( < 50 K) due to antiferromagnetic coupling between Ce-local moments and Mn-moments. For = 0.4, the resistivity showed a maximum around 200 K which corresponds to ordering temperature of cerium. Since these results are similar to that observed in the Sr-containing La0.5-CeSr0.5MnO3 ( = 0-0.4) system, we suggest that the cerium ions are in the trivalent state and the anomalous behaviour has been attributed to a Kondo-like effect.

  20. Crystal structure, Raman spectroscopy and microwave dielectric properties of layered-perovskite BaA{sub 2}Ti{sub 3}O{sub 10} (A = La, Nd and Sm) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Santosh Kumar; Murthy, V.R.K., E-mail: vrkm@iitm.ac.in

    2015-06-15

    Dependence of microwave dielectric properties on the structural characteristics of BaA{sub 2}Ti{sub 3}O{sub 10} (A = La, Nd and Sm) was investigated. All the compounds were prepared by solid-state reaction method and the structural parameters were obtained from Rietveld refinement of powder diffraction data of the compounds. The dielectric constant (ε{sub r}) increased due to decrease in molar volume of the compound, which was observed as a result of smaller ionic radii. Quality factor (Q × ƒ) of BaSm{sub 2}Ti{sub 3}O{sub 10} (BST) and BaLa{sub 2}Ti{sub 3}O{sub 10} (BLT) were found to be lowest (10,490 GHz) and highest (20,860 GHz) respectively, which was explained in terms of average bond strength between B-site cations and oxygen anions. Raman spectroscopy was also used to analyze the B–O bond strength with the help of A{sub g} mode. The temperature coefficient of resonant frequency (τ{sub ƒ}) was correlated with respective octahedral-distortion in the structure. - Highlights: • Increase of B-site bond strength enhanced the quality factor. • FWHM of A{sub g} mode also confirmed the increase of quality factor from Sm to La. • Effect of B-site octahedral distortion on τ{sub f}.

  1. Analysis of Fe, Ca, Ti, Ba, Ce, Zr and La element in the Sea sediment at Muria peninsula by X RF method

    International Nuclear Information System (INIS)

    he analysis of metals (Fe, Ca, Ti, Ba, Ce, Zr and La) in the sea sediment environmental samples at Muria peninsula has been carried out with X-Ray Fluorescence (XRF) method. The aim of this analysis is to know the distribution metals which accommodate the recent environmental data in supporting the license of site and Environmental Impact Assessment (EIA) for the Nuclear Power Plants (NPP). Samples taken preparation and analysis based on the procedures of environmental analysis. The result analysis that contents of mayor elements in 7 sea sediment location of sampling were Ca, Ti and Fe with concentration are (6.74 – 11.69 ) %; (0.74 – 6.89 ) % and (0.45 -1.94 ) % successively; while minor elements were Ba, Ce, Zr and La with concentration are 451.4 – 1331.6 ) mg/kg; (201.8 – 427.3) mg/kg; (192.3 – 338.5) mg/kg dan (171.7 – 298.4) mg/kg. The statistic test result shows that sampling location there is a significant difference all of element with the level significant of 95 %. (author)

  2. Synthesis, structure and ionic conductivity in scheelite type Li0.5Ce0.5−LnMoO4 ( = 0 and 0.25, Ln = Pr, Sm)

    Indian Academy of Sciences (India)

    Dipankar Saha; Giridhar Madras; Aninda J Bhattacharyya; Tayur N Guru Row

    2011-01-01

    Scheelite type solid electrolytes, Li0.5Ce0.5−LnMoO4 ( = 0 and 0.25, Ln = Pr, Sm) have been synthesized using a solid state method. Their structure and ionic conductivity () were obtained by single crystal X-ray diffraction and ac-impedance spectroscopy, respectively. X-ray diffraction studies reveal a space group of 41/ for Li0.5Ce0.5−LnMoO4 ( = 0 and 0.25, Ln = Pr, Sm) scheelite compounds. The unsubstituted Li0.5Ce0.5MoO4 showed lithium ion conductivity ∼ 10−5-10−3 −1cm-1 in the temperature range of 300-700°C ( = 2.5 × 10−3 −1cm-1 at 700°C). The substituted compounds show lower conductivity compared to the unsubstituted compound, with the magnitude of ionic conductivity being two (in the high temperature regime) to one order (in the low temperature regime) lower than the unsubstituted compound. Since these scheelite type structures show significant conductivity, the series of compounds could serve in high temperature lithium battery operations.

  3. Combined effect of chemical pressure and valence electron concentration through the electron-deficient Li substitution on the RE{sub 4}LiGe{sub 4} (RE=La, Ce, Pr, and Sm) system

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Gnu; Jeon, Jieun; Kim, Youngjo [Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 361-763 (Korea, Republic of); Kwon Kang, Sung [Department of Chemistry, Chungnam National University, Daejeon, Chungnam 305-764 (Korea, Republic of); Ahn, Kyunghan [Advanced Materials Research Center, Samsung Advanced Institute of Technology, Yongin-si, Gyeonggi-do 446-712 (Korea, Republic of); You, Tae-Soo, E-mail: tsyou@chungbuk.ac.kr [Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 361-763 (Korea, Republic of)

    2013-09-15

    Four members of the RE{sub 4}LiGe{sub 4} (RE=La, Ce, Pr, and Sm) system have been prepared by high-temperature reaction method and characterized by X-ray diffractions. All compounds crystallize in the orthorhombic Gd{sub 5}Si{sub 4}-type structure (space group Pnma, Pearson code oP16) with bonding interactions for interslab Ge{sub 2} dimers. The Li substitution for rare-earth elements in the RE{sub 4}LiGe{sub 4} system leads to a combined effect of the increased chemical pressure and the decreased valance electron concentration (VEC), which eventually results in the structure transformation from the Sm{sub 5}Ge{sub 4}-type with all broken interslab Ge–Ge bond for the parental RE{sub 5}Ge{sub 4} to the Gd{sub 5}Si{sub 4}-type structure for the ternary RE{sub 4}LiGe{sub 4} (RE=La, Ce, Pr, and Sm) system. Site-preference between rare-earth metals and Li is proven to generate energetically the most favorable atomic arrangements according to coloring-problem, and the rationale is provided using both the size-factor and the electronic-factor related, respectively, to site-volume and electronegativity as well as QVAL values. Tight-binding, linear-muffin-tin-orbital (TB-LMTO) calculations are performed to investigate electronic densities of states (DOS) and crystal orbital Hamilton population (COHP) curves. The influence of reduced VEC for chemical bonding including the formation of interslab Ge{sub 2} dimers is also discussed. The magnetic property measurements prove that the non-magnetic Li substitution leads to the ferromagnetic (FM)-like ground state for Ce{sub 4}LiGe{sub 4} and the co-existence of antiferromagntic (AFM) and FM ground states for Sm{sub 4}LiGe{sub 4}. - Graphical abstract: Reported is a combined effect of the chemical pressure and the reduced VEC caused by the smaller monovalent non-magnetic Li substitution for the larger trivalent magnetic rare-earth metals in the RE{sub 4}LiGe{sub 4} (RE=La, Ce, Pr, and Sm) system. This results in the structure

  4. Magnetic manipulation by resistance switching in CeO2/PrBa2Cu3O7−δ/Pt heterostructure: The role of oxygen vacancies

    International Nuclear Information System (INIS)

    Pronounced bipolar resistance switching with a good retention property has been observed in CeO2/PrBa2Cu3O7−δ/Pt heterostructure. The low resistance state and high resistance state exhibited distinguished ferromagnetic signals, as compared to the nearly non-magnetic initial state. It is found that the migration of the oxygen vacancies under electric field is mainly responsible for the electric and the magnetic changes. The modified interfacial electronic structure by the oxygen vacancy migration and the trapping/detrapping of the carriers leads to the resistance switching. The exchange interaction of the hydrogen-like orbitals formed around the singly occupied oxygen vacancies in CeO2 is accounting for the emerged and modulated ferromagnetic signals. Temperature dependence of resistance in the low resistance state follows a variable range hopping law, further confirming that the amount of oxygen vacancies in the CeO2 layer directly affects the hydrogen-like orbital radius, which determines the strength of the ferromagnetic coupling

  5. Preparation of Eu2+ and Ce3+ co-activated phosphors with optimal composition in (Ba,Sr)2ZnS3 solid solution series by polymerizable complex method

    International Nuclear Information System (INIS)

    The series of Ba2-xSrxZnS3:Eu2+,Ce3+ (x = 0.3, 0.4, 0.5) red emission phosphors was synthesized by a solution based technique employing polymerizable complex method. The prepared materials conformed to Ba2MnS3 type crystal structure. Red fluorescence could be efficiently exited by the blue light of 445nm; thus these phosphors are prospective in white LED lighting application. The emission intensity vs. Sr concentration showed a distinct maximum at x = 0.4, while co-doping with Eu2+ and Ce3+ allowed for enhancement of emission intensity by 5-15% compared to the Ce free samples. The maximum emission intensity at 670nm exhibited by the material with optimal Sr concentration approached 80% compared to one of the best commercially available YAG:Ce3+.

  6. Seven new rare-earth transition-metal oxychalcogenides: Syntheses and characterization of Ln4MnOSe6 (Ln=La, Ce, Nd), Ln4FeOSe6 (Ln=La, Ce, Sm), and La4MnOS6

    International Nuclear Information System (INIS)

    The quaternary oxychalcogenides Ln4MnOSe6 (Ln=La, Ce, Nd), Ln4FeOSe6 (Ln=La, Ce, Sm), and La4MnOS6 have been synthesized by the reactions of Ln (Ln=La, Ce, Nd, Sm), M (M=Mn, Fe), Se, and SeO2 at 1173K for the selenides or by the reaction of La2S3 and MnO at 1173K for the sulfide. Warning: These reactions frequently end in explosions. These isostructural compounds crystallize with two formula units in space group C6v4-P63mc of the hexagonal system. The cell constants (a, c in A) at 153K are: La4MnOSe6, 9.7596(3), 7.0722(4); La4FeOSe6, 9.7388(4), 7.0512(5); Ce4MnOSe6, 9.6795(4), 7.0235(5); Ce4FeOSe6, 9.6405(6), 6.9888(4); Nd4MnOSe6, 9.5553(5), 6.9516(5); Sm4FeOSe6, 9.4489(5), 6.8784(5); and La4MnOS6, 9.4766(6), 6.8246(6). The structure of these Ln4MOQ6 compounds comprises a three-dimensional framework of interconnected LnOQ7 bicapped trigonal prisms, MQ6 octahedra, and the unusual LnOQ6 tricapped tetrahedra

  7. Composite Fe - BaCe0.2Zr0.6Y0.2O2.9 Anodes for Proton Conductor Fuel Cells

    DEFF Research Database (Denmark)

    Lapina, Alberto; Chatzichristodoulou, Christodoulos; Holtappels, Peter;

    2014-01-01

    Symmetrical cells with Fe - BaCe0.2Zr0.6Y0.2O2.9 composite electrodes are produced by screen printing and infiltration, using BaCe0.2Zr0.6Y0.2O2.9 as electrolyte. The electrochemical performance of the composite electrode is studied by impedance spectroscopy at 250–500◦C in dry and wet hydrogen...... has potential to be a promising anode material for PCFCs, once electronic percolation in the electrode is improved and degradation is reduced. © 2014 The Electrochemical Society....

  8. Influence of anode pore forming additives on the densification of supported BaCe0.7Ta0.1Y0.2O3−δ electrolyte membranes based on a solid state reaction

    NARCIS (Netherlands)

    Bi, Lei; Fang, Shumin; Tao, Zetian; Zhang, Shangquan; Peng, Ranran; Liu, Wei

    2009-01-01

    We describe a solid state reaction for the preparation of both NiO–BaCe0.7Ta0.1Y0.2O3−δ anode substrates and BaCe0.7Ta0.1Y0.2O3−δ (BCTY10) electrolyte membranes on porous NiO–BCTY10 anode substrates. The amounts of the pore forming additive in the substrates showed a significant influence on the den

  9. Complexes of o-Vanillin oxime with La(III), Ce(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III), Ho(III) and Yb(III)

    International Nuclear Information System (INIS)

    Ten complexes of lanthanides with o-vanillin oxime have been swynthesised and characterised. The composition of the complexes as determined by elemental and thermal analyses, infrared electronic spectral and magnetic moment studies is [Ln(C8H8NO3)3.XH2O], where X=2 when Ln=La, Ce, Pr, Nd, Sm and X=3 when Ln=Gd, Dy, Tb, Ho, Yb; C8H8NO3- represents the anion of the ligand. (author). 16 refs., 2 figs., 2 tables

  10. Hydrogen Permeation Properties of Perovskite-type BaCe0.9Mn0.1O3-δDense Ceramic Membrane

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The electrical conduction properties of dense BaCe0.9Mn0.1O3-δ (BCM10) membrane were investigated in the temperature range of 600-900℃. High ionic and electronic conductivities at elevated temperatures make BCM10 a potential ceramic material for hydrogen separation. Hydrogen permeation through BCM10 membranes was studied using a hightemperature permeation cell. Little hydrogen could be detected at the sweep side. However,appreciable hydrogen can permeate through BCM10 membrane coated with porous platinum black,which shows that the process of hydrogen permeation through BCM10 membranes was controlled by the catalytic decomposition and recomposition of hydrogen on the surfaces of BCM10 membranes.

  11. Chemical stability and electrical property of Ba1.03Ce0.6Zr0.2Yb0.2O3-α ceramic

    Institute of Scientific and Technical Information of China (English)

    WANG Maoyuan; QIU Ligan; CAO Xu

    2011-01-01

    Ba1.03Ce0.6Zr0.2Yb0.2O3-α ceramic was prepared by solid state reaction.Phase composition,surface and cross-section morphologies of the material were characterized by using X-ray diffractometer (XRD) and scanning electron microscopy (SEM),respectively.Its chemical stability against carbon dioxide and water steam at high temperature was tested.Ionic conduction of the material was investigated by ac impedance spectroscopy and gas concentration cell methods under different gas atmospheres in the temperature range of 500-900 ℃.Using the ceramic as solid electrolyte and porous platinum as electrodes,the hydrogen-air fuel cell was constructed,and the cell performance at the temperature from 500 to 900 ℃ was examined.The results indicated that Ba1.03Ce06Zr0.2Yb0.2O3-α was a single-phase perovskite-type orthorhombic system,with high density and good chemical stability under carbon dioxide and water steam atmospheres at high temperature.In wet hydrogen,the material was a pure protonic conductor with the protonic transport number of I from 500 to 700 ℃,a mixed conductor of proton and electron with the protonic transport numbers of 0.945-0.916 from 800 to 900 ℃.In wet air,the material was a mixed conductor of proton,oxide ion and electronic hole.The protonic transport numbers were 0.013-0.003,and the oxide ionic transport numbers were 0.346-0.265.Under hydrogen-air fuel cell conditions,the material was a mixed conductor of proton,oxide ion and electron,the ionic transport numbers were 0.945-0.848.The fuel cell could work stably,and at 900 ℃,the maximum power output density was 36.5 mW/cm2.

  12. Crystal structure of the R{sub 3}Ag{sub 1-{delta}}SiS{sub 7} (R = La, Ce, Pr, Nd, Sm, {delta} = 0.10-0.23) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Daszkiewicz, M. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna Street 2, P.O. Box 1410, Wroclaw 50-950 (Poland)], E-mail: m.daszkiewicz@int.pan.wroc.pl; Gulay, L.D. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna Street 2, P.O. Box 1410, Wroclaw 50-950 (Poland); Department of General and Inorganic Chemistry, Volyn State University, Voli Avenue 13, Lutsk 43009 (Ukraine); Lychmanyuk, O.S. [Department of General and Inorganic Chemistry, Volyn State University, Voli Avenue 13, Lutsk 43009 (Ukraine); Pietraszko, A. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna Street 2, P.O. Box 1410, Wroclaw 50-950 (Poland)

    2008-07-28

    The crystal structure of the R{sub 3}Ag{sub 1-{delta}}SiS{sub 7} (R = La, Ce, Pr, Nd, Sm, {delta} = 0.10-0.23, space group P6{sub 3}, Pearson symbol hP23.80 - 23.54) compounds were determined by means of X-ray single crystal diffraction (a = 1.04168(8) nm, c = 0.57825(4) nm, R1 = 0.0116 for La{sub 3}Ag{sub 0.90}SiS{sub 7}; a = 1.0312(1) nm, c = 0.57395(7) nm, R1 = 0.0152 for Ce{sub 3}Ag{sub 0.82}SiS{sub 7}; a = 1.0248(1) nm, c = 0.57223(5) nm, R1 = 0.0105 for Pr{sub 3}Ag{sub 0.85}SiS{sub 7}; a = 1.0192(1) nm, c = 0.57020(6) nm, R1 = 0.0292 for Nd{sub 3}Ag{sub 0.81}SiS{sub 7}, a = 1.0100(1) nm, c = 0.56643(6) nm, R1 = 0.0208 for Sm{sub 3}Ag{sub 0.77}SiS{sub 7}. Gradual decrease of the silver amount in the series of chalcogenides was found.

  13. Crystal structure and magnetic properties of R{sub 3}Fe{sub 0.5}GeS{sub 7} (R = Y, La, Ce, Pr, Sm, Gd, Tb, Dy, Ho, Er and Tm)

    Energy Technology Data Exchange (ETDEWEB)

    Daszkiewicz, M. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław (Poland); Pashynska, Yu.O. [Department of Material Science, Lutsk National Technical University, L’vivska str. 75, 43018 Lutsk (Ukraine); Marchuk, O.V. [Department of Inorganic and Physical Chemistry, Eastern European National University, Voli Ave 13, 43009 Lutsk (Ukraine); Gulay, L.D. [Department of Ecology and Protection of Environment, Eastern European National University, Voli Ave 13, 43009 Lutsk (Ukraine); Kaczorowski, D., E-mail: D.Kaczorowski@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław (Poland)

    2014-12-15

    Highlights: • Identification of eleven novel R{sub 3}Fe{sub 0.5}GeS{sub 7} compounds. • Refinement of their crystal structures from single crystal XRD data. • Determination of magnetic behaviour in eight R{sub 3}Fe{sub 0.5}GeS{sub 7} phases. - Abstract: The crystal structure of quaternary compounds R{sub 3}Fe{sub 0.5}GeS{sub 7} (R = Y, La, Ce, Pr, Sm, Gd, Tb, Dy, Ho, Er and Tm) was determined by means of single-crystal and powder X-ray diffraction methods. It is of the hexagonal La{sub 3}Mn{sub 0.5}SiS{sub 7} type (space group P6{sub 3}, Pearson symbol hP23) The R atoms occupy trigonal prisms capped with two additional atoms, the Fe atoms are located inside octahedra, and the Ge atoms have tetrahedral environment. Magnetic properties of the compounds R{sub 3}Fe{sub 0.5}GeS{sub 7} (R = Ce, Pr, Sm, Gd, Tb, Dy, Er and Tm) were studied down to 1.72 K. Their magnetic behaviour results from combined contributions due to R{sup 3+} and Fe{sup 2+} sublattices. In each material magnetic exchange interactions are dominated by antiferromagnetic correlations. In most of them, the exchange interactions give rise to long-range magnetic orderings at low temperatures.

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

    Science.gov (United States)

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

    2016-08-01

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

  15. Tunable emission and efficient energy-transfer properties of Ce{sup 3+} and Mn{sup 2+} co-doped Ba{sub 3}Gd(PO{sub 4}){sub 3} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ren; Hu, Yihua; Jin, Yahong; Chen, Li; Wang, Xiaojuan [Guangdong University of Technology, School of Physics and Optoelectronic Engineering, Guangzhou (China)

    2014-11-15

    The tunable emission color phosphors Ba{sub 3}Gd(PO{sub 4}){sub 3}: Ce{sup 3+}, Mn{sup 2+} were synthesized by conventional high-temperature solid-state reaction method. The photoluminescence properties and energy transfer (ET) of the Ce{sup 3+} and Mn{sup 2+} co-doped Ba{sub 3}Gd(PO{sub 4}){sub 3} phosphors were studied systematically. Through an efficient energy-transfer process, the obtained phosphors show both dual-emission including a ultraviolet (UV) to blue emission originating from Ce{sup 3+} and a reddish-orange emission from Mn{sup 2+} under UV excitation (∝310 nm) with considerable intensity. When the Ce{sup 3+} doping content is fixed at 0.05, the emission color tone can be adjusted from blue through reddish-purple and ultimately to red region by tuning the contents of Mn{sup 2+} from 0.01 to 0.5. The critical distance between Ce{sup 3+} and Mn{sup 2+} was calculated to be 12.23 Aa. The concentration quenching of Mn{sup 2+} was experimentally found to be 0.3. The energy-transfer efficiency was discussed and the ET mechanism between Ce{sup 3+} and Mn{sup 2+} ions was proved to be dipole-dipole interaction. The Ce{sup 3+} and Mn{sup 2+} co-doped Ba{sub 3}Gd(PO{sub 4}){sub 3} phosphors are potential UV-convertible candidates in UV white-light LEDs for the energy transfer from Ce{sup 3+} to Mn{sup 2+} ions. (orig.)

  16. Crystallographic and magnetic properties of R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy)

    CERN Document Server

    Han Xiu Feng; Li Qi; Zhang Mao Cai; Zhou Shou Zeng

    1998-01-01

    A systematic investigation of crystallographic and magnetic properties of nitride R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 (R = Y, Ce, Nd, Sm, Gd, Tb, and Dy) has been performed. Nitrogenation leads to a relative volume expansion of about 6%. The lattice constants and unit cell volume decrease with increasing rare-earth atomic number from Nd to Dy, reflecting the lanthanide contraction. On average, the Curie temperature increases due to the nitrogenation to about 200 K compared with its parent compound. Generally speaking, nitrogenation also results in a remarkable improvement of the saturation magnetization and anisotropy fields at 4.2 K and room temperature for R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 compared with their parent compounds. The transition temperature indicates the spin reorientations of R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 for R Nd and Sm are at around 375 and 370 K which are higher than that of R sub 3 Fe sub 2 sub 9 sub - sub x V sub x for R = Nd and Sm 145...

  17. New tetragonal derivatives of cubic NaZn{sub 13}-type structure: RNi{sub 6}Si{sub 6} compounds, crystal structure and magnetic ordering (R=Y, La, Ce, Sm, Gd–Yb)

    Energy Technology Data Exchange (ETDEWEB)

    Pani, M.; Manfrinetti, P.; Provino, A. [INFM and Dipartimento di Chimica e Chimica Industriale, Universita‘ di Genova, Via Dodecaneso 31, 16146 Genova (Italy); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4M1 (Canada); Morozkin, A.V., E-mail: morozkin@general.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V.; Garshev, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Isnard, O. [Université Grenoble Alpes, Inst NEEL, BP166, F-38042 Grenoble (France); CNRS, Institut NEEL, 25 rue des martyrs, F-38042 Grenoble (France)

    2014-02-15

    Novel RNi{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure for R=La–Ce (tP52, space group P4/nbm N 125-1) and new YNi{sub 6}Si{sub 6}-type structure for R=Y, Sm, Gd–Yb (tP52, space group P4{sup ¯}b2N 117) that are tetragonal derivative of NaZn{sub 13}-type structure, like LaCo{sub 9}Si{sub 4}-type. The CeNi{sub 6}Si{sub 6}, GdNi{sub 6}Si{sub 6}, TbNi{sub 6}Si{sub 6}, DyNi{sub 6}Si{sub 6} and HoNi{sub 6}Si{sub 6} compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 5 K. However, the inverse paramagnetic susceptibility of LaNi{sub 6}Si{sub 6} does not follow Curie–Weiss law. The DyNi{sub 6}Si{sub 6} shows ferromagnetic-like saturation behaviour at 5 K in applied fields of 50 kOe, giving rise to a magnetic moment value of 6.5 μ{sub B}/f.u. in 50 kOe. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi{sub 6}Si{sub 6} with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. - Graphical abstract: Novel (La, Ce)Ni{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure and (Y, Sm, Gd–Yb) adopt the new YNi{sub 6}Si{sub 6}-type structure that are tetragonal derivative of NaZn{sub 13}-type structure, like LaCo{sub 9}Si{sub 4}-type. The CeNi{sub 6}Si{sub 6}, GdNi{sub 6}Si{sub 6}, TbNi{sub 6}Si{sub 6}, DyNi{sub 6}Si{sub 6} and HoNi{sub 6}Si{sub 6} compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 4.2 K. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi{sub 6}Si{sub 6} with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. Display Omitted - Highlights: • The new (La, Ce)Ni{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure. • The new (Y, Sm, Gd–Yb)Ni{sub 6}Si{sub 6} compounds adopt the new YNi{sub 6}Si{sub 6}-type structure. • TbNi{sub 6}Si

  18. Syntheses, Structure, Magnetism, and Optical Properties of the Ordered Interlanthanide Copper Chalcogenides Ln{sub 2}YbCuQ{sub 5} (Ln = La, Ce, Pr, Nd, Sm; Q = S, Se): Evidence for Unusual Magnetic Ordering in Sm{sub 2}YbCuS{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-11-19

    Ln{sub 2}YbCuQ{sub 5} (Ln = La, Ce, Pr, Nd, Sm; Q = S, Se) have been prepared by direct reaction of the elements in Sb{sub 2}Q{sub 3} (Q = S, Se) fluxes at 900 °C. All compounds have been characterized by single-crystal X-ray diffraction methods and they are isotypic. The structure of Ln{sub 2}YbCuQ{sub 5} consists of one-dimensional {sup 1}{sub {infinity}} [YbCuQ{sub 5}]{sup 6-} ribbons extending along the b axis that are connected by larger Ln{sup 3+} ions. Each ribbon is constructed from two single chains of [YbQ{sub 6}] octahedra with one double chain of [CuQ{sub 5}] trigonal bipyramids in the middle. All three chains connect with each other via edge-sharing. There are two crystallographically unique Ln atoms, one octahedral Yb site, and two disordered Cu positions inside of distorted Q{sub 5} trigonal bipyramids. Both Ln atoms are surrounded by eight Q atoms in bicapped trigonal prisms. The magnetic properties of Ln{sub 2}YbCuQ{sub 5} have been characterized using magnetic susceptibility and heat capacity measurements, while their optical properties have been explored using UV-vis-NIR diffuse reflectance spectroscopy. Cesub 2}YbCuSe{sub 5}, La{sub 2}YbCuS{sub 5}, Ce{sub 2}YbCuS{sub 5}, and Pr{sub 2}YbCuS{sub 5} are Curie-Weiss paramagnets. La{sub 2}YbCuSe{sub 5} and Nd{sub 2}YbCuS{sub 5} show evidence for short-range antiferromagnetic ordering at low temperatures. Sm{sub 2}YbCuS{sub 5} shows magnetic ordering at 5.9 K, followed by negative magnetization at low external fields. The band gaps of La{sub 2}YbCuSe{sub 5}, Ce{sub 2}YbCuSe{sub 5}, La{sub 2}YbCuS{sub 5}, Ce{sub 2}YbCuS{sub 5}, Pr{sub 2}YbCuS{sub 5}, Nd{sub 2}YbCuS{sub 5},and Sm{sub 2}YbCuS{sub 5} are 1.15 eV, 1.05 eV, 1.45 eV, 1.37 eV, 1.25 eV, 1.35 eV, and 1.28 eV respectively.

  19. Time-dependent performance change of single layer fuel cell with Li0.4Mg0.3Zn0.3O/Ce0.8Sm0.2O2-delta composite

    OpenAIRE

    Hu, Huiging; Lin, Qizhao; Zhu, Zhigang; Liu, Xiangrong; Zhu, Bin

    2014-01-01

    A Large-size engineering single layer fuel cell (SLFC) consisting of a nano-structured Li0.4Mg0.3Zn0.3O2-delta/Ce0.8Sm0.2O2-delta (LMZSDC) composite with an active area of 25 cm(2) (6 cm x 6 cm x 0.1 cm) is successfully fabricated. The SLFC is evaluated by testing the cell durability with a time-dependent degradation using an H-2 fuel and an air oxidant at 600 degrees C for over 120 h. A maximum power of 12.8 W (512 mW cm(-2)) is achieved at 600 degrees C. In the initial operation stage aroun...

  20. The stannides RE{sub 3}Au{sub 6}Sn{sub 5} (RE = La, Ce, Pr, Nd, Sm). Synthesis, structure, magnetic properties and {sup 119}Sn Moessbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fickenscher, Thomas; Rodewald, Ute C.; Niehaus, Oliver; Gerke, Birgit; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Haverkamp, Sandra; Eckert, Hellmut [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie

    2015-07-01

    The Ce{sub 3}Pd{sub 6}Sb{sub 5}-type rare earth stannides RE{sub 3}Au{sub 6}Sn{sub 5} (RE = La, Ce, Pr, Nd, Sm) were synthesized by arc-melting of the elements and subsequent annealing in open tantalum crucibles within sealed evacuated silica ampoules. The polycrystalline samples were studied by powder X-ray diffraction. The structures of three crystals were refined from single crystal X-ray diffractometer data: Pmmn, a = 1360.3(9), b = 455.9(2), c = 1023.6(4) pm, wR2 = 0.0275, 1069 F{sup 2} values, 48 variables for Ce{sub 3}Au{sub 6}Sn{sub 5}, a = 1352.4(4), b = 455.1(1), c = 1023.7(3) pm, wR2 = 0.0367, 1160 F{sup 2} values, 48 variables for Nd{sub 3}Au{sub 6}Sn{sub 5}, and a = 1339.8(2), b = 452.80(7), c = 1012.4(2) pm, wR2 = 0.1204, 1040 F{sup 2} values, 49 variables for Sm{sub 3}Au{sub 5.59(2)}Sn{sub 5.41(2)}. One of the gold sites of the samarium compound shows a significant degree of Au/Sn mixing. The RE{sub 3}Au{sub 6}Sn{sub 5} structures are composed of three-dimensional [Au{sub 6}Sn{sub 5}] polyanionic networks with the two crystallographically independent rare earth atoms in larger cages, i.e., RE1 rate at Au{sub 10}Sn{sub 6} and RE2 rate at Au{sub 8}Sn{sub 8}. The [Au{sub 6}Sn{sub 5}] network is stabilized by Au-Sn (266-320 pm), Au-Au (284-301 pm) as well as Sn-Sn (320 pm; distances given for the cerium compound) interactions. Temperature-dependent magnetic susceptibility measurements reveal an antiferromagnetic ordering only for Sm{sub 3}Au{sub 6}Sn{sub 5}, while the other compounds exhibit Curie-Weiss paramagnetism. {sup 119}Sn Moessbauer spectroscopy shows resonances in the typical range for intermetallic tin compounds where tin takes part in the polyanionic network [isomer shifts between 1.73(1) and 2.28(1) mm . s{sup -1}]. With the help of theoretical electric field gradient calculations using the WIEN2k code it was possible to resolve the spectroscopic contributions of all three crystallographically independent atomic tin sites in the {sup 119}Sn

  1. Effects of annealing on the microstructure, corrosion resistance, and mechanical properties of RE65Co25Al10 (RE=Ce, La, Pr, Sm, and Gd) bulk metallic glasses

    International Nuclear Information System (INIS)

    The effects of annealing on the microstructure, corrosion resistance and mechanical properties of the RE65Co25Al10 (RE=Ce, La, Pr, Sm, and Gd) bulk metallic glasses (BMGs) were studied. Microstructural changes are induced after annealing below the onset crystallization temperature of 484 K, resulting in the variation of thermal stability and crystallization behavior. A proper annealing enhances the corrosion resistance in 3.5 wt% NaCl solution, which can be attributed to reduction of the electrochemical activity and galvanic coupling effects in the chloride solution. Moreover, the RE-based BMG annealed at 484 K possesses the higher corrosion potential and lower corrosion current density, combined with the corrosion morphologies, which suggests the best corrosion resistance. Annealing can also obviously change the mechanical properties and fracture morphologies. It presents that free volume annihilation can cause more difficulty in the elastic atom rearrangement for the as-annealed RE-based BMGs

  2. Preparation and Spectra Properties of BaO-Al2O3-P2O5-Sm2O3 System Protection Glasses

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The forming-regions of phosphate glasses doped with high Sm2O3 contents were studied by two step melting method. The relationship between absorption spectrum and rare earth contents was also discussed. The spectra of BASP glasses were measured by spectrophotometer. The results show that the forming regions will shrink with the increase of Al2O3 and it is difficult to form glass when [PO4]/[AlO4]<2. The forming regions tend to be a closed elliptical, and the intensity of characteristic absorption peak increases gradually with the increase of Sm2O3, the absorption lines broadens non-uniformly and there is approximate linear relation between optical density at the 1064 nm wavelength and Sm2O3 content.

  3. New orthorhombic derivative of CaCu{sub 5}-type structure: RNi{sub 4}Si compounds (R=Y, La, Ce, Sm, Gd–Ho), crystal structure and some magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Morozkin, A.V., E-mail: morozkin@general.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India)

    2013-12-15

    The crystal structure of new YNi{sub 4}Si-type RNi{sub 4}Si (R=Y, La, Ce, Sm, Gd–Ho) compounds has been established using powder X-ray diffraction. The YNi{sub 4}Si structure is a new structure type, which is orthorhombic derivative of CaCu{sub 5}-type structure (space group Cmmm N 65, oC12). GdNi{sub 4}Si and DyNi{sub 4}Si compounds order ferromagnetically at 25 and 19 K, respectively whereas YNi{sub 4}Si shows antiferromagnetic nature. At 15 K, DyNi{sub 4}Si shows second antiferromagnetic-like transition. The magnetic moment of GdNi{sub 4}Si at 5 K in 50 kOe field is ∼7.2 μ{sub B}/f.u. suggesting a completely ordered ferromagnetic state. The magnetocaloric effect of GdNi{sub 4}Si is calculated in terms of isothermal magnetic entropy change and it reaches the maximum value of −12.8 J/kg K for a field change of 50 kOe near T{sub C} ∼25 K. - Graphical abstract: The RNi{sub 4}Si (R=Y, La, Ce, Sm, Gd–Ho) compounds crystallize in new YNi{sub 4}Si-type structure which is orthorhombic derivative of the basic CaCu{sub 5}-type structure. GdNi{sub 4}Si and DyNi{sub 4}Si compounds show the ferromagnetic-like ordering, whereas.YNi{sub 4}Si has the antiferromagnetic nature. The GdNi{sub 4}Si demonstrates the big magnetocaloric effect near temperature of ferromagnetic ordering. The relationship between initial CaCu{sub 5}-type DyNi{sub 5} and YNi{sub 4}Si-type DyNi{sub 4}Si lattices.

  4. Improving SiO2 impurity tolerance of Ce0.8Sm0.2O1.9: Synergy of CaO and ZnO in scavenging grain-boundary resistive phases

    Science.gov (United States)

    Ge, Lin; Ni, Qing; Cai, Guifan; Sang, Tianyi; Guo, Lucun

    2016-08-01

    Rapid oxygen ion conduction, which is important in solid oxide fuel cell (SOFC) electrolytes, is often dramatically hindered by the presence of even small concentrations of impurities such as SiO2, which is ubiquitous in ceramic processing. In this study, rapid degradation of the grain boundary (GB) conduction of Ce0.8Sm0.2O1.9 (SDC) is observed with increasing SiO2 addition from 0 to 1 wt%. Nearly complete GB conduction recovery is achieved through synergy between CaO and ZnO in the SDC + x wt% Si systems. Scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS) demonstrate the formation of a Ca-, Si-, and Sm-containing secondary phases, which is related to the enhancements in GB conductivity and reductions in activation energy. The scavenging effect of CaO is verified in this study and ZnO is observed to promote the scavenging reaction. Compared with the single-addition case (CaO/ZnO), the much higher SiO2 impurity tolerance of the combined system suggests the commercial potential of the "scavenger + promoter" strategy presented in this work.

  5. Rectification in (La,Sr)MnO3/(Ba,Sr)TiO3/(La,Ce)2CuO4 trilayer p-i-n junctions

    International Nuclear Information System (INIS)

    Oxide trilayer p-i-n junctions, with p-type La0.67Sr0.33MnO3 (LSMO) manganite layer and n-type La1.89Ce0.11CuO4 (LCCO) cuperate layer separated by Ba0.7Sr0.3TiO3 (BST) titanite insulator layer, have been deposited in situ and characterized. With the increment of the insulator layer thickness, the I-V characteristic of such p-i-n junctions changes from symmetric to asymmetric, and then to symmetric again, given the highest rectifying performance at the BST layer of about 25 nm thick. The largest asymmetry, defined as the ratio of dI/dV at +2 V and -2 V, respectively, is found >1000. The insulator layer thickness dependency indicates that the transport properties of the p-i-n junctions are dominated by the interplay between the interior fields at the LSMO/BST and BST/LCCO interfaces

  6. Water vapour solubility and conductivity study of the proton conductor BaCe(0.9 − x)ZrxY0.1O(3 − δ)

    DEFF Research Database (Denmark)

    Ricote, Sandrine; Bonanos, Nikolaos; Caboche, G:

    2009-01-01

    sample. The direct current conductivity has been measured as a function of oxygen partial pressure, at a water vapour partial pressure of 0.015 atm. The total conductivity has been resolved into a p-type and an ionic component using a fitting procedure appropriate to the assumed defect model. An......The perovskite BaCe(0.9 − x)ZrxY0.1O(3 − δ) has been prepared by solid state reaction at 1400 °C and conventional sintering at 1700 °C. Water uptake experiments performed between 400 and 600 °C, at a water vapour pressure of 0.02 atm, provide data on the concentration of protons incorporated in the...... estimation of the protonic component was made by assuming a conductivity isotope effect between 1.4 and 1.8. The total conductivity, obtained using impedance spectroscopy has been measured as a function of temperature in the water and heavy water exchanged states. The activation energy has been found to be 0...

  7. Hydrogen Permeation Performance of Ni-BaZr0.1Ce0.7Y0.2O3-δ Metal-Ceramic Hollow Fiber Membrane

    Science.gov (United States)

    Yang, Chun-li; Xu, Qi-ming; Zhu, Zhi-wen; Liu, Wei

    2012-04-01

    A dense Ni-BaZr0.1Ce0.7Y0.2O3-δ (BZCY) cermet hollow fiber is fabricated by sintering NiO-BZCY hollow fiber precursors prepared by phase inversion method in 5%H2/95%Ar and its hydrogen permeation performance is investigated. The Ni-BZCY hollow fiber membrane possesses a “sandwich" structure. Finger-like structures are observed near both the inner and outer surfaces, while a dense layer is present in the center part. With 200 mL/min wet 20%H2/80%N2 on the shell side and 150 mL/min high purity Ar on the core side, the hydrogen permeation flux through the Ni-BZCY hollow fiber membrane at 900 °C is 0.53 μmol/cm2s. Owing to a high packing density, the hydrogen permeation flux per unit volume is greatly improved and membrane components composed of an assembly of hollow fibers may be applied in industrial hydrogen separation.

  8. Hydrogen Permeation Performance of Ni-BaZr0.1Ce0.7Y0.2O3-δ Metal-Ceramic Hollow Fiber Membrane

    Institute of Scientific and Technical Information of China (English)

    Chun-li Yang; Qi-ming Xu; Zhi-wen Zhu; Wei Liu

    2012-01-01

    A dense Ni-BaZr0.1Ce0.7Y0.2O3-δ (BZCY) cermet hollow fiber is fabricated by sintering NiOBZCY hollow fiber precursors prepared by phase inversion method in 5%H2/95%Ar and its hydrogen permeation performance is investigated. The Ni-BZCY hollow fiber membrane possesses a "sandwich" structure.Finger-like structures are observed near both the inner and outer surfaces,while a dense layer is present in the center part.With 200 mL/min wet 20%H2/80%N2 on the shell side and 150 mL/min high purity Ar on the core side,the hydrogen permeation flux through the Ni-BZCY hollow fiber membrane at 900 ℃ is 0.53 μmol/cm2s.Owing to a high packing density,the hydrogen permeation flux per unit volume is greatly improved and membrane components composed of an assembly of hollow fibers may be applied in industrial hydrogen separation.

  9. Thermoelectric properties of hot-pressed Tl9LnTe6 (Ln = La, Ce, Pr, Nd, Sm, Gd, Tb) and Tl10−xLaxTe6 (0.90 ⩽ x ⩽ 1.05)

    International Nuclear Information System (INIS)

    Highlights: • Electrical conductivity and thermal conductivity increase with the Ln series from the left to the right. • Seebeck coefficient and figure-of-merit increase with the Ln series from the right to the left. • As for Tl10−xLaxTe6, the best properties were found when x = 1. • The highest figure-of-merit of these materials is zTmax = 0.57 at 600 K, realized for Tl9LaTe6. • This constitutes a huge improvement over the cold-pressed and sintered materials with their zTmax = 0.21. - Abstract: In the first part of this work, thallium lanthanide tellurides with composition Tl9LnTe6 (Ln = La, Ce, Pr, Nd, Sm, Gd, Tb) have been prepared and their high temperature electrical and thermal transport properties investigated. Nearly single phase samples were obtained. Rietveld refinement results showed that Tl9CeTe6 had an exceptionally small unit cell volume of 1033 Å3. The electrical conductivity and thermal conductivity increased across the lanthanide series from La to Tb. On the other hand, the Seebeck coefficient values decreased with Ln varying from La to Tb. Tl9SmTe6 or Tl9GdTe6 constituted an exception, as the Seebeck coefficient of Tl9SmTe6 was smaller than that of Tl9GdTe6. Tl9LaTe6 has the largest figure-of-merit of this series. Thereafter, Tl10−xLaxTe6 samples were prepared with x = 0.90, 0.95, 1.00, 1.05, 1.10, aiming toward higher zT through composition optimization and expanding of the measurement temperature range. With the increasing La content, the unit cell volume increased, while the electrical conductivity, thermal conductivity and lattice thermal conductivity decreased, and the Seebeck coefficient increased. The highest zT = 0.57 was observed for Tl9LaTe6 at 600 K

  10. Profile of yttrium segregation in BaCe{sub 0,9}Y{sub 0,1}O{sub 3-{delta}} as function of sintering temperature; Perfil da segregacao do itrio em BaCe{sub 0,9}Y{sub 0,1}O{sub 3-{delta}} em funcao da temperatura de sinterizacao

    Energy Technology Data Exchange (ETDEWEB)

    Hosken, C.M.; Souza, D.P.F. de, E-mail: camila.hosken@gmail.co [Universidade Federal de Sao Carlos (LAPCEC/UFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais. Lab. de Preparacao e Caracterizacao Eletrica em Ceramicas

    2010-07-01

    Researches on solid oxide fuel cells indicate barium cerate perovskite as a very attractive material for using as electrolyte due to its high protonic conductivity. The objective of this work is investigate the yttrium segregation during sintering of BaCe{sub 0,9}Y{sub 0,1}O{sub 3-{delta}} doped with Zn O as a sintering aid. The powders were prepared by citrate process. Powders were isostatic pressed into pellets and sintered in air at 1200, 1275, 1325 and 1400 deg C. The samples were characterized by scanning electron microscopy, X-ray diffraction and impedance spectroscopy. Secondary phase containing Yttrium and Cerium was detected as sintering temperature increased. Increase of the lattice parameter and activation energy for electrical conductivity were also detected on samples sintered at 1400 deg C. (author)

  11. Reactivity of Ce-ZrO{sub 2} (doped with La-, Gd-, Nb-, and Sm-) toward partial oxidation of liquefied petroleum gas: Its application for sequential partial oxidation/steam reforming

    Energy Technology Data Exchange (ETDEWEB)

    Laosiripojana, N. [The Joint Graduate School of Energy and Environment, King Mongkut' s University of Technology Thonburi, Bangkok, 10140 (Thailand); Sutthisripok, W. [Department of Mining and Materials Engineering, Prince of Songkla University, Songkhla (Thailand); Kim-Lohsoontorn, P. [Department of Chemical Engineering, Mahidol University, Nakorn Pathom 73170 (Thailand); Assabumrungrat, S. [Center of Excellence in Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330 (Thailand)

    2010-07-15

    Ce-ZrO{sub 2} was found to have useful partial oxidation activity under moderate temperatures. It converted liquefied petroleum gas (LPG) to H{sub 2}, CH{sub 4}, CO and CO{sub 2} with small amounts of C{sub 2}H{sub 6} and C{sub 2}H{sub 4} formations depending on the operating temperature and provided significantly greater resistance toward carbon deposition compared to conventional Ni/Al{sub 2}O{sub 3}. The doping of La, Sm and Gd over Ce-ZrO{sub 2} considerably improved catalytic reactivity, whereas Nb-doping reduced its reactivity. It was found that the impact of doping element is strongly related to the degrees of oxygen storage capacity (OSC) and/or lattice oxygen (O{sub O}{sup x}) of materials. Among all catalysts, La-doped Ce-ZrO{sub 2} was observed to have highest OSC value and was the most active catalyst. Above 850 C with inlet LPG/O{sub 2} molar ratio of 1.0/1.0, the main products from the reaction over La-doped Ce-ZrO{sub 2} were H{sub 2}, CH{sub 4}, CO, and CO{sub 2}. Practical application was then proposed by applying La-doped Ce-ZrO{sub 2} as primary oxidative catalyst for sequential partial oxidation/steam reforming of LPG (by using Ni/Al{sub 2}O{sub 3} as the steam reforming catalyst). At 850 C, this coupling pattern offered high H{sub 2} yield (87.0-91.4%) without any hydrocarbons left in the products indicating the complete conversion of LPG to syngas. H{sub 2} yield from this system was almost identical to that observed from the typical autothermal reforming over Rh/Al{sub 2}O{sub 3}; hence it could efficiently replace the requirement of expensive noble metal catalysts to reform LPG properly. (author)

  12. Evaluation of resonance parameters of Mo, Tc, Te, Ba, La, Ce, Pr, Nd, Pm, Sm and Eu isotopes for JENDL-2 fission product file

    International Nuclear Information System (INIS)

    The resonance parameters of 39 fission product nuclides have been evaluated. The present work is a part of the evaluation of 100 fission product nuclei for JENDL-2 by Japanese Nuclear Data Committee. All the available experimental data were collected, stored in REPSTOR system and compared with one another. The evaluation was made on the basis of the experimental data. The precise description of the evaluation is given in this report. The presently evaluated resonance parameters are tabulated in Appendix with the experimental data. (author)

  13. Luminescence of Ce 3+ -Doped MB2Si2O8 (M = Sr, Ba): A Deeper Insight into the Effects of Electronic Structure and Stokes Shift

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Qi [Sun Yat-Sen Univ., Guangzhou, (China); Liu, Chunmeng [Sun Yat-Sen Univ., Guangzhou, (China); Hou, Dejian [Sun Yat-Sen Univ., Guangzhou, (China); Zhou, Weijie [Sun Yat-Sen Univ., Guangzhou, (China); Ma, Chong-Geng [Chongqing Univ. of Posts and Telecommunications (China); Liu, Guokui [Argonne National Lab. (ANL), Argonne, IL (United States); Brik, Mikhail G. [Chongqing Univ. of Posts and Telecommunications (China); Tao, Ye [Chinese Academy of Sciences (CAS), Beijing (China); Liang, Hongbin [Sun Yat-Sen Univ., Guangzhou, (China)

    2015-12-18

    A series of Sr 1 -2x CexNaxB2Si2O8 and Ba 1-2x CexKxB2Si2O8 (x = 0.005, 0.01, 0.02, 0.04, 0.06, 0.08) samples were synthesized by a high-temperature solid-state reaction. The low temperature excitation, emission, and fluorescence decay spectra together demonstrated that all spectral bands arise from the Ce 3+ ions located at only one kind of lattice site. The first-principles calculations of the structural and electronic properties of pure and Ce 3+2Si2O8 (M = Sr, Ba) were performed, and the obtained results were used for understanding the structural changes after doping and identification of the observed position of the host absorption bands. The measured 4f-5d excitation and emission spectra of Ce3+ ions doped in MB2Si2O8 were analyzed and simulated in the framework of the crystal-field (CF) theory. The electron-phonon coupling effect generally ignored in most studies published so far was also taken into account by applying the configurational coordinate model. The validity of such a combined insight into the 5d CF energy level positions and the Stokes shift has been confirmed by analyzing the dependence of the Ce 3+

  14. Experimental evidence of hydrogen–oxygen decoupled diffusion into BaZr0.6Ce0.25Y0.15O3−δ

    International Nuclear Information System (INIS)

    The electrical properties of BaZr0.6Ce0.25Y0.15O3−δ (BZCY) were studied as a function of both oxygen partial pressure (-2.65⩽log(PO2atm-1)⩽-0.62) and water vapor activity (-3.33⩽log(PH2Oatm-1⩽-1.3)) in the temperature range of 973–1073 K. The total conductivity slightly increased in reducing atmospheres with increasing water vapor activity because of the relative contribution to the total conductivity by the redox reaction at the given thermodynamic conditions. The partial conductivities of protons, holes and oxygen vacancies were successfully calculated, and the activation energy determined for proton transport was 0.3 ± 0.1 eV. The chemical diffusivity of oxygen at a fixed water vapor activity, D∼vO, could only be evaluated from Fick’s second law during oxidation and reduction at the fixed water vapor activity. However, twofold nonmonotonic conductivity relaxation behaviors were clearly confirmed in the temperature range investigated during hydration/dehydration. If PO2 represents the fixed oxygen partial pressure, D∼iH is the hydrogen chemical diffusivity at PO2 and D∼vH is the oxygen chemical diffusivity at PO2, it was observed that D∼iH>D∼vH at all experimental conditions, suggesting that the hydrogen chemical diffusion is always faster than oxygen on hydration/dehydration in the temperature range studied

  15. Crystal structure of R{sub 3}Ge{sub 1+x}Se{sub 7} (R = La, Ce, Pr, Sm, Gd and Tb, x = 0.43-0.49) and magnetic properties of Ce{sub 3}Ge{sub 1.47}Se{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Daszkiewicz, M. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, P.O. Box 1410, 50-950 Wroclaw (Poland); Strok, O.M. [Department of General and Inorganic Chemistry, Volyn National University, Voli Ave 13, 43009 Lutsk (Ukraine); Gulay, L.D. [Department of Ecology and Protection of Environment, Volyn National University, Voli Ave 13, 43009 Lutsk (Ukraine); Kaczorowski, D., E-mail: D.Kaczorowski@int.pan.wroc.p [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, P.O. Box 1410, 50-950 Wroclaw (Poland)

    2010-10-22

    Research highlights: {yields} Determination and refinement of the crystal structures of R{sub 3}Ge{sub 1+x}Se{sub 7} (R = La, Ce, Pr, Sm, Gd and Tb, x = 0.43-0.49) compounds from single-crystal X-ray diffraction data {yields} Determination of the magnetic behavior in single-crystalline Ce{sub 3}Ge{sub 1.47}Se{sub 7}. - Abstract: The crystal structures of ternary compounds R{sub 3}Ge{sub 1+x}Se{sub 7} (Dy{sub 3}Ge{sub 1.25}S{sub 7} structure type, space group P6{sub 3}, Pearson symbol hP22 + 2x, a = 10.7656(7) A, c = 6.0801(5) A, R1 = 0.0186 for La{sub 3}Ge{sub 1.48}Se{sub 7}; a = 10.684(1) A, c = 6.0611(8) A, R1 = 0.0257 for Ce{sub 3}Ge{sub 1.47}Se{sub 7}; a = 10.6408(9) A, c = 6.0548(7) A, R1 = 0.0290 for Pr{sub 3}Ge{sub 1.49}Se{sub 7}; a = 10.4419(7) A, c = 6.0283(6) A, R1 = 0.0201 for Sm{sub 3}Ge{sub 1.48}Se{sub 7}; a = 10.325(7) A, c = 6.0506(7) A, R1 = 0.0269 for Gd{sub 3}Ge{sub 1.45}Se{sub 7}; a = 10.2747(7) A, c = 6.0743(5) A, R1 = 0.0499 for Tb{sub 3}Ge{sub 1.43}Se{sub 7}) were determined by means of X-ray single-crystal diffraction. The R atoms occupy trigonal prisms capped with two additional atoms. The Ge atoms are located in octahedral and tetrahedral environment. The compound Ce{sub 3}Ge{sub 1.47}Se{sub 7} exhibits a Curie-Weiss type paramagnetic behavior due to the presence of fairly stable local magnetic moments on cerium ions. No hint at any magnetic phase transition was observed down to 1.72 K.

  16. Far-infrared reflection spectra of R1-xPrxBa2Cu3O7-y samples (R Sm, Gd, Tm). An evidence of phase separation in the samples

    International Nuclear Information System (INIS)

    Although rather intensive studies have been performed on the systems Y1-xPrxBa2Cu3O7-y during the last six years, the answers to a number of questions regarding the systems remain unclear and open for discussion. Even the basic issue of the fundamental mechanism causing the depression of the critical transition temperature Tc as the Pr concentration increases remains a subject for debate. Various mechanisms have been proposed, including hole filling, magnetic pair breaking, and hybridization mechanisms. A central problem has been the conflicting results on the valence state of Pr implied by the different experiments. On the other hand, an important phenomenon has been found in the R1-xPrxBa2Cu3O7-y systems (R rare-earth element). Tc is not only dependent on the Pr concentration, but also on the ionic radius R, which has not been found in the pure RBa2Cu3O7-y. We have ever discussed the above-mentioned issue based upon phase separation and hole number change models separately. However, until now, we have no experiment to confirm our hypothesis directly. In this note, the authors measured the far-infrared spectra of R1-xPrxBa2Cu3O7-y (R = Sm, Gd, Tm) (R-Pr systems) and found that the peak of the R site vibrational mode shifted toward high wave numbers when R is partially substituted by Pr. This gives us a useful information about the understanding of the above issues. (orig.)

  17. Thermoelectric properties of Tl10−xLnxTe6, with Ln = Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er, and 0.25 ⩽ x ⩽ 1.32

    International Nuclear Information System (INIS)

    Highlights: ► The thermoelectric properties of Tl10−xLnxTe6 were determined. ► For each Ln, the Seebeck coefficient increases with increasing Ln amount. ► For each Ln, the electrical conductivity decreases with increasing Ln amount. ► For each Ln, the thermal conductivity decreases with increasing Ln amount. ► The lattice thermal conductivity is always very low. - Abstract: In the present study, thallium lanthanide tellurides, Tl10−xLnxTe6, Ln = Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er; 0.25 ⩽ x ⩽ 1.32 were investigated. All these thallium lanthanide tellurides are isostructural to Tl9BiTe6, adopting the space group I4/mcm with mixed occupancy of Tl and Ln at the 4c site. The unit cell volume increases with increasing lanthanide content for a given Ln and decreases across the lanthanides series for a specific stoichiometry. Tl9CeTe6 has exceptionally small unit cell volume of 1019(1) Å3, compared to, e.g., Tl9LaTe6 with 1047.2(1) Å3 and Tl9NdTe6 with 1028(1) Å3. The Seebeck coefficient values, S, increase as the lanthanide content increases for a given Ln. On the other hand, the electrical conductivity, σ, and thermal conductivity, κ, values decrease with increasing Ln content for a given Ln. The opposite trend (S decreases while σ and κ increase) is mostly observed across the lanthanide series for Tl10−xLnxTe6, x ≈ 1. For instance, S of Tl9.08Nd1.02(6)Te6, Tl9.0Gd1.0(1)Te6 and Tl9.05Er0.95(5)Te6 are 81, 59, 49 μV/K, respectively, at 500 K. Consequently, the dimensionless figure-of-merit values increase for a given Ln with increasing x (and temperature). The highest ZT value of ∼0.20 was obtained for Tl8.98Nd1.02(6)Te6 and Tl8.99Sm1.01(7)Te6 at ∼550 K.

  18. Crystal structures of the R{sub 3}Mg{sub 0.5}GeS{sub 7} (R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Huch, M.R. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine)]. E-mail: gulay@lab.univer.lutsk.ua; Gulay, L.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine)

    2006-11-09

    The crystal structures of the R{sub 3}Mg{sub 0.5}GeS{sub 7} (R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er) compounds (La{sub 3}CuSiS{sub 7} structure type, space group P6{sub 3}, Pearson symbol hP23) were determined by means of X-ray powder diffraction: a = 0.9788(1) nm, c = 0.57745(5) nm, R {sub Bragg} = 0.0814 (Y{sub 3}Mg{sub 0.5}GeS{sub 7}); a = 1.0262(2) nm, c = 0.57849(7) nm, R {sub Bragg} 0.0687 (Ce{sub 3}Mg{sub 0.5}GeS{sub 7}); a = 1.01249(3) nm, c = 0.58040(2) nm, R {sub Bragg} = 0.0832 (Pr{sub 3}Mg{sub 0.5}GeS{sub 7}); a = 1.00701(3) nm, c = 0.58047(3) nm, R {sub Bragg} = 0.0636 (Nd{sub 3}Mg{sub 0.5}GeS{sub 7}); a = 0.99500(3) nm, c 0.57872(3) nm, R {sub Bragg} = 0.0870 (Sm{sub 3}Mg{sub 0.5}GeS{sub 7}); a = 0.99319(3) nm, c = 0.57083(3) nm, R {sub Bragg} = 0.0901 (Gd{sub 3}Mg{sub 0.5}GeS{sub 7}); a = 0.98007(5) nm, c = 0.57843(4) nm, R {sub Bragg} = 0.0859 (Tb{sub 3}Mg{sub 0.5}GeS{sub 7}); a 0.97698(4) nm, c = 0.57675(5) nm, R {sub Bragg} = 0.0931 (Dy{sub 3}Mg{sub 0.5}GeS{sub 7}); a = 0.9735(2) nm, c = 0.57941(7) nm, R {sub Bragg} = 0.0763 (Ho{sub 3}Mg{sub 0.5}GeS{sub 7}); a = 0.9694(2) nm, c = 0.57994(7) nm, R {sub Bragg} 0.0724 (Er{sub 3}Mg{sub 0.5}GeS{sub 7}). The R-centered trigonal prisms, Mg-centered octahedra and Ge-centered tetrahedra can be selected in the crystal structure of the R{sub 3}Mg{sub 0.5}GeS{sub 7} compounds.

  19. Unprecedented CO2-promoted hydrogen permeation in Ni-BaZr0.1Ce0.7Y0.1Yb0.1O(3-δ) membrane.

    Science.gov (United States)

    Fang, Shumin; Brinkman, Kyle; Chen, Fanglin

    2014-01-01

    Conventional Ni-BaCeO3-based membranes possess high hydrogen permeation flux but suffer serious flux degradation in CO2-containing atmosphere because of the formation of BaCO3 insulating layer. In this work, we report a novel Ni-BaZr0.1Ce0.7Y0.1Yb0.1O(3-δ) (Ni-BZCYYb) membrane, capable of both high hydrogen permeation flux and stable performance in CO2-containing atmosphere at 900 °C. Most importantly, the flux is found to be promoted rather than being diminished by CO2 normally observed for other high temperature proton conductors. The flux enhancement in Ni-BZCYYb membrane is attributed to the increase of moisture content in feed gas. When CO2 is introduced, the reverse water-gas shift reaction takes place generating H2O and CO. This work demonstrates that CO2 can be beneficial rather than detrimental for hydrogen permeation membranes that possess high chemical stability. PMID:24328190

  20. Influence of the ratio between Ni and BaCe0.9Y0.1O3-δ on microstructural and electrical properties of proton conducting Ni-BaCe0.9Y0.1O3-δ anodes

    International Nuclear Information System (INIS)

    Research highlights: → The influence of ratio between Ni and BaCe0.9Y0.1O3-δ on the microstructural and electrical properties of anode substrates was investigated. → Changing of Ni:BCY10 ratio has a significant influence on the microstructure of conducting pathways in anode substrates, but the electrical characterization showed comparable activation energies of samples before and after reduction. → Percolation through Ni particles properly took place even though the amount of Ni is decreased. This was confirmed by high conductivity values (σ* > 40 S cm-1) of all samples after reduction. → Fuel cell tests showed very small decreasing (less than 5%) in the maximum power output between fuel cells with the highest and the lowest amount of nickel in anode composition. → The anode with 40 wt.% of nickel could be used for fabrication of anode supported PCFC without any significant deterioration of the performances. → Fuel cells with composite anode substrates showed higher maximum power output comparing to the fuel cell with platinum anode. - Abstract: Cermet anode substrates Ni-BaCe0.9Y0.1O3-δ (Ni-BCY10) with varied ratios between Ni and BCY10 were prepared. BCY10 powders were prepared by the citrate-nitrate auto-combustion method and anode substrates were prepared by the method of evaporation and decomposition of solutions and suspensions. Sintered anode substrates were reduced and their properties were examined before and after reduction as a function of the ratio between Ni and BCY10. Microstructural properties of the pellets were investigated using X-ray diffraction analysis and field emission scanning electron microscopy. The influence of the Ni:BCY10 ratio on the microstructure of conducting paths through ceramic and metal parts was discussed. Impedance spectroscopy measurements were used for evaluation of electrical properties of the anode pellets. The high conductivity values of reduced anodes confirmed percolation through Ni particles even for an

  1. Seleção de eletrodos para caracterização elétrica de Y-BaCeO3 contendo ZnO como aditivo de sinterização Electrode selection for electrical characterization of Y-BaCeO3 with ZnO as sintering aid

    Directory of Open Access Journals (Sweden)

    C. M. Hosken

    2012-09-01

    Full Text Available Neste trabalho é abordada a escolha da pasta de eletrodo para realização da caracterização elétrica de amostras de BaCeO3 dopado com ítrio e contendo ZnO como aditivo de sinterização. A sinterização ocorreu via fase líquida. Foi utilizada uma pasta de eletrodo de platina e outra de prata cujas temperaturas de cura são 1100 °C e 750 °C, respectivamente. A análise das interfaces amostra-eletrodo por microscopia eletrônica de varredura revelou que durante a cura da pasta de platina, devida a elevada temperatura, ocorreu exsudação de fase que permaneceu entre a superfície original da amostra e o eletrodo. Por conseqüência, durante a caracterização elétrica por espectroscopia de impedância foi detectada polarização adicional na interface amostra-eletrodo comprometendo a veracidade dos valores de resistividade elétrica do material em análise o que não ocorreu com o uso do eletrodo de prata devida sua menor temperatura de cura.This work deals with the choice of electrodes for realizing the electrical characterization of Yttrium doped-BaCeO3 sample which contains ZnO as sintering aid. The sintering occurred through liquid phase. It were used platinum and silver pastes which curing temperatures are 1100 °C and 750 °C, respectively. Scanning electron microscopy characterization of sample-electrode interfaces showed that during the curing of the platinum paste, due to the high temperature, occurred phase exudation which remained between the primary sample surface and electrode. Consequently, electrical characterization by impedance spectroscopy detected additional polarization at interface sample-electrode becoming non-veracious the electrical resistivity values of the material under analysis. No additional polarization was detected for silver electrodes due to the lowest curing temperature.

  2. Composite cathode La0.4Sr0.4TiO3-δ-Ce0.8Sm0.2O2-δ impregnated with Ni for high-temperature steam electrolysis

    Science.gov (United States)

    Gan, Yun; Qin, Qingqing; Chen, Shigang; Wang, Yan; Dong, Dehua; Xie, Kui; Wu, Yucheng

    2014-01-01

    Composite Ni-SDC (Samaria doped Ceria) cathodes are able to operate in strong reducing atmospheres for steam electrolysis, and composite cathodes based on redox-stable La0.4Sr0.4TiO3 (LSTO) have demonstrated promising performances without the reducing gas flow. However, the electro-catalytic activity of cathodes based on LSTO is insufficient for the efficient electrochemical reduction of steam or carbon oxide. In this work, catalytic-active Ni nanoparticles were loaded on a La0.4Sr0.4TiO3-δ-Ce0.8Sm0.2O2-δ cathode (Ni-loaded LSTO-SDC) via an impregnation method to improve the electrode performances for direct steam electrolysis. The synergetic effect of catalytically-active Ni nanoparticles and the redox-stable LSTO-SDC skeleton contributed to the improved performances and the excellent stability of the cathode for direct steam electrolysis. The current efficiency with a Ni-loaded cathode was enhanced by 3% and 17% compared to the values with a bare LSTO-SDC cathode under 2.0 V of applied voltage at 800 °C with a flow of 3% H2O/5% H2/Ar and 3% H2O/Ar to cathodes, respectively.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-06-12

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

  4. 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.

  5. Fabrication of Y1-xRE xBa2Cu3O y films on single crystalline substrates and IBAD buffered metallic tapes by advanced TFA-MOD process

    International Nuclear Information System (INIS)

    We fabricated Y1-xSm xBa2Cu3O y and YSm xBa2Cu3O y (YSmBCO) films on SrTiO3 (STO) single crystalline substrates and IBAD buffered metallic tapes (PLD-CeO2/IBAD-GZO/Hastelloy) by the advanced TFA-MOD process by mixing TFA salts of Y, Sm, Ba and Cu naphthenate, and tried to improve the superconductivity properties compared with those of the pure YBa2Cu3O7-δ (YBCO). As a result, J c values of Y1-xSm xBa2Cu3O y films with x = 0.05 or 0.3, which were fabricated on STO substrates, were improved under the high magnetic fields compared with those of the YBCO without substitution. However, Sm segregation was detected near the STO substrate which was obtained by the TEM-EDS (transmission electron microscopy-energy-dispersive X-ray spectroscopy) analysis. On the other hand, Y1-xSm xBa2Cu3O y films with x = 0.05 and YSm xBa2Cu3O y films with x = 0.3, which were fabricated on IBAD buffered metallic substrates, also improved I c value under the high magnetic fields compared with those of the YBCO without substitution. Moreover, from the TEM-EDS analysis, Y or Sm segregation was not found. The difference in the Sm segregation behavior between the film on STO and CeO2 buffered substrates could be explained by the difference in the ratios of the misfit parameters between YBCO/substrate and SmBCO/substrate. Additionally, it was considered that the above phenomenon might be unique in the MOD system and could not be observed in the PLD system, because of the difference in the crystal growth mechanism. In the film of YSm0.3Ba2Cu3O y, we observed the grains of (Y, Sm)2O3 and (Y, Sm)2Cu2O5 by TEM observation. We will further investigate the origin of pinning centers

  6. Performance of XSCoF (X=Ba, La and Sm) and LSCrX' (X'=Mn, Fe and Al) perovskite-structure materials on LSGM electrolyte for IT-SOFC

    International Nuclear Information System (INIS)

    X0.5Sr0.5Co0.8Fe0.2O3-δ (X=Ba, La and Sm) and La0.75Sr0.25Cr0.5X'0.5O3-δ (X'=Mn, Fe and Al) mixed ionic-electronic conducting perovskite-based oxides have been tested as SOFC electrode materials on La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) electrolytes under different atmospheres (air, oxygen, argon and dry and wet 5% H2/Ar) and the area-specific resistances (ASR) were compared. Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCoF) possesses the lowest ASR values in air (0.04Ωcm2 at 1073K) whilst La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCrM) possesses the lowest ASR values in wet 5% H2/Ar (0.28Ωcm2 at 1073K). In addition, fuel cell tests were carried out using wet 5% H2/Ar as fuel and air as oxidant. The maximum power density (∼123mWcm-2) at 1073K was reached with the electrolyte-supported system BSCoF/LSGM/LSCrM (∼1.5mm electrolyte thickness). Furthermore, LSCrX' materials were used simultaneously as cathode and anode in fuel cell tests and the symmetric system LSCrM/LSGM/LSCrM (∼1.5mm electrolyte thickness) reached a maximum power density of ∼54mWcm-2 at 1073K

  7. Vortex creep and critical current densities J c in a 2 μm thick SmBa2Cu3O7‑d coated conductor with mixed pinning centers grown by co-evaporation

    Science.gov (United States)

    Haberkorn, N.; Coulter, Y.; Condó, A. M.; Granell, P.; Golmar, F.; Ha, H. S.; Moon, S. H.

    2016-07-01

    We report the critical current densities J c and flux creep rates in a 2 μm thick SmBa2Cu3O7–δ coated conductor produced by co-evaporation. The sample presents strong pinning produced by correlated disorder (CD) (boundaries between growth islands, dislocations and twin boundaries) as well as random nanoparticles. Correlated pinning along the c-axis was evidenced due to the appearance of a large peak in the angular critical current, centered at H║c. The analysis of the critical current density J c (with the magnetic field applied parallel (H║c) and at 45° of the c-axis (H║45°)) indicates that CD assists pinning throughout the temperature range. For all temperatures and at both angles the in-field dependence of J c exhibits a power-law behavior. The contribution of CD drops when the field is rotated to intermediate angles between the c axis and a–b axis (i. e. H║45°), which derives in a reduction of the absolute J c value and poorer in-field dependences. The flux creep rate depends on the angle and its values remain approximately constant within the power-law regime. For H║c and H║45° and for magnetic fields lower than 20 kOe, the flux relaxation presents characterizing glassy exponents μ = 1.70 and μ = 1.32, respectively.

  8. Structural and relaxor-like dielectric properties of unfilled tungsten bronzes Ba5-5xSm5xTi5xNb10-5xO30

    Science.gov (United States)

    Wei, T.; Dong, Z.; Zhao, C. Z.; Guo, Y. Y.; Zhou, Q. J.; Li, Z. P.

    2016-03-01

    New unfilled tetragonal tungsten bronze (TTB) oxides, Ba5-5xSm5xTi5xNb10-5xO30 (BSTN-x), where 0.10 ≤ x ≤ 0.35, have been synthesized in this work. Their crystal structure was determined and analyzed based on Rietveld structural refinement. It is found that single TTB phase can be formed in a particular x range (i.e., 0.15 ≤ x ≤ 0.3) due to the competition interaction between tolerance factor and electronegativity difference. Furthermore, dielectric and ferroelectric results indicate that phase transitions and ferroelectric states are sensitive to x. Referring to the local chemistry, we suggest that the raise of vacancies at the A2-site compared with that of A1-site will intensely depress the normal ferroelectric phase and is in favor of relaxor ferroelectric state. Macroscopically, previous A-site size difference standpoint on fill TTB compounds cannot give a reasonable explanation about the variation of dielectric maximum temperature (Tm) for present BSTN-x compounds. Alternatively, tetragonality (c/a) is adopted which can well describe the variation of Tm in whole x range. In addition, one by one correspondence between tetragonality and electrical features can be found, and the compositions involving high c/a are usually stabilized in normal ferroelectric phase. It is believed that c/a is a more appropriate parameter to illustrate the variation of ferroelectric properties for unfilled TTB system.

  9. Improvement in J{sub c} performance below liquid nitrogen temperature for SmBa{sub 2}Cu{sub 3}O{sub y} superconducting films with BaHfO{sub 3} nano-rods controlled by low-temperature growth

    Energy Technology Data Exchange (ETDEWEB)

    Miura, S., E-mail: miura-syun12@ees.nagoya-u.ac.jp; Yoshida, Y.; Ichino, Y.; Xu, Q. [Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8603 (Japan); Matsumoto, K. [Department of Materials Science and Engineering, Kyushu Institute of Technology, Kitakyushu 804-8550 (Japan); Ichinose, A. [Electric Power Engineering Research Laboratory, Central Research Institute of Electric Power Industry, Yokosuka, Kanagawa 240-0196 (Japan); Awaji, S. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

    2016-01-01

    For use in high-magnetic-field coil-based applications, the critical current density (J{sub c}) of REBa{sub 2}Cu{sub 3}O{sub y} (REBCO, where RE = rare earth) coated conductors must be isotropically improved, with respect to the direction of the magnetic field; these improvements must be realized at the operating conditions of these applications. In this study, improvement of the J{sub c} for various applied directions of magnetic field was achieved by controlling the morphology of the BaHfO{sub 3} (BHO) nano-rods in a SmBCO film. We fabricated the 3.0 vol. % BHO-doped SmBCO film at a low growth temperature of 720 °C, by using a seed layer technique (T{sub s} = 720 °C film). The low-temperature growth resulted in a morphological change in the BHO nano-rods. In fact, a high number density of (3.1 ± 0.1) × 10{sup 3} μm{sup −2} of small (diameter: 4 ± 1 nm), discontinuous nano-rods that grew in various directions, was obtained. In J{sub c} measurements, the J{sub c} of the T{sub s} = 720 °C film in all directions of the applied magnetic field was higher than that of the non-doped SmBCO film. The J{sub c}{sup min} (6.4 MA/cm{sup 2}) of the former was more than 6 times higher than that (1.0 MA/cm{sup 2}) of the latter at 40 K, under 3 T. The aforementioned results indicated that the discontinuous BHO nano-rods, which occurred with a high number density, exerted a 3D-like flux pinning at the measurement conditions considered. Moreover, at 4.2 K and under 17 T, a flux pinning force density of 1.6 TN/m{sup 3} was realized; this value was comparable to the highest value recorded, to date.

  10. Ternary aurides RE4Mg3Au10 (RE = La, Ce, Pr) and RE4Cd3Au10 (RE = Y, La-Nd, Sm, Gd-Dy). Ordering variants of the Zr7Ni10 type

    International Nuclear Information System (INIS)

    The intermetallic gold compounds RE4Mg3Au10 (RE = La, Ce, Pr) and RE4Cd3Au10 (RE = Y, La-Nd, Sm, Gd-Dy) were obtained from the elements through high-frequency melting in sealed niobium tubes and subsequent annealing in a muffle furnace. The new aurides crystallize with the Ca4In3Au10-type structure. They were characterized through Guinier powder patterns. The structures of Pr4.46Cd2.54Au10 and Tb4.38Cd2.62Au10 were refined from single crystal X-ray diffractometer data: Cmce, a = 1396.73(6), b = 1009.38(3), c = 1019.51(3) pm, wR2 = 0.0423, 1281 F2 values, 47 variables for Pr4.46Cd2.54Au10 and a = 1362.68(3), b = 995.52(4), c = 1003.79(3) pm, wR2 = 0.0381, 1594 F2 values, F2 47 variables for Tb4.38Cd2.62Au10. The 8e sites of both crystals show substantial Cd/Pr respectively Cd/Tb mixing, indicating small homogeneity ranges for all RE4+xMg3-xAu10 and RE4+xCd3-xAu10 aurides. The gold atoms in these aurides form a pronounced two-dimensional substructure (275-327 pm Au-Au in Pr4.46Cd2.54Au10) which encages the Mg1/Cd1 (coordination number 8) and RE2 (coordination number 11) atoms. These blocks are separated by the Mg2/Cd2 and RE1 atoms with an intergrowth of Mg2/Cd2 rate at Au8 and RE1 rate at Au10 polyhedra. Temperature dependent magnetic susceptibility and specific heat measurements of Tb4Cd3Au10 have shown antiferromagnetic ordering at a Neel temperature of 12(1) K.

  11. Crystal structure and magnetic properties of R{sub 3}Mn{sub 0.5}GeS{sub 7} (R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er)

    Energy Technology Data Exchange (ETDEWEB)

    Daszkiewicz, M. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław (Poland); Marchuk, O.V. [Department of Inorganic and Physical Chemistry, Eastern European National University, Voli Ave 13, 43009 Lutsk (Ukraine); Gulay, L.D. [Department of Ecology and Protection of Environment, Eastern European National University, Voli Ave 13, 43009 Lutsk (Ukraine); Kaczorowski, D., E-mail: D.Kaczorowski@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław (Poland)

    2014-10-15

    Highlights: • Identification of two novel compounds Tb{sub 3}Mn{sub 0.5}GeS{sub 7} and Ho{sub 3}Mn{sub 0.5}GeS{sub 7}. • Refinement of crystal structures of ten R{sub 3}Mn{sub 0.5}GeS{sub 7} single-crystalline phases. • Finding of R and Mn contributions to magnetic behavior in R{sub 3}Mn{sub 0.5}GeS{sub 7} phases. - Abstract: The crystal structures of quaternary R{sub 3}Mn{sub 0.5}GeS{sub 7} (R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er) compounds of La{sub 3}Mn{sub 0.5}SiS{sub 7} structure type (space group P6{sub 3}, Pearson symbol hP23) were determined by means of single crystal X-ray diffraction. The R atoms occupy trigonal prisms with two additional atoms, the Mn atoms are located in octahedra, while the Ge atoms are located in tetrahedra. Magnetic studies were performed on polycrystalline samples of Y{sub 3}Mn{sub 0.5}GeS{sub 7}, Pr{sub 3}Mn{sub 0.5}GeS{sub 7} and Dy{sub 3}Mn{sub 0.5}GeS{sub 7}. The former compound is a Curie–Weiss paramagnet due to magnetic moments carried on trivalent Mn ions. The other ones exhibit localized paramagnetic behavior due to both Mn{sup 3+} and R{sup 3+} sublattices. While the Dy-bearing sulfide orders antiferromagnetically below 5.5 K, no unambiguous indication of any magnetic ordering in Y{sub 3}Mn{sub 0.5}GeS{sub 7} and Pr{sub 3}Mn{sub 0.5}GeS{sub 7} was found down to 1.72 K.

  12. Synthesis and characterization of novel Ce0.8Sm0.2Fe0.9Ir0.03Co0.07O3−δ perovskite material and possible application as a cathode for low–intermediate temperature SOFCs

    International Nuclear Information System (INIS)

    Highlights: • Ce0.8Sm0.2Fe0.9Ir0.03Co0.07O3−δ was synthesized using sol–gel methods. • Material was thoroughly characterized using Raman, FTIR, XRD, HRTEM, SEM, and TGA. • Electrochemical performance showed the materials are a promising new cathode material for low temperature SOFC. - Abstract: A novel perovskite material, Ce0.8Sm0.2Fe0.9Ir0.03Co0.07O3−δ was synthesized using a sol–gel technique. The materials were calcined at temperatures of 800 °C, 900 °C, and 1000 °C and then characterized using X-ray diffraction, Raman and infrared spectroscopy, high resolution transmission electron microscopy and scanning electron microscopy (SEM). The particle sizes and crystallite sizes increased with increasing calcination temperature and formed perovskite type materials with some separate magnetite and iridium oxide. The powders were used to assemble button cells using samarium doped ceria as the electrolyte and NiO/SDC as the anode materials. The electrochemical properties were investigated using a Fiaxell open flanges test set-up and a Nuvant™ Powerstat-05 potentiostat/galvanostat. The Ce0.8Sm0.2Fe0.9Ir0.03Co0.07O3−δ cathode material calcined at 1000 °C exhibited the most promising performance, with a maximum power density of 0.400 W/cm2, a current density of 0.8 A/cm2, and a corresponding area specific resistance of 0.247 Ωcm2 at 500 °C. The button cells were reasonably stable over15 h

  13. Conductivity, transport number measurements and hydration thermodynamics of BaCe0.2Zr0.7Y(0.1 − ξ)NiξO(3 − δ)

    DEFF Research Database (Denmark)

    Ricote, Sandrine; Bonanos, Nikolaos; Wang, Hsiang-Jen;

    2011-01-01

    -site of the perovskite is in agreement with similar data obtained earlier for the two compositions. The first aim of this work was to evaluate the conductivity of BaCe0.2Zr0.7Y(0.1 − ξ)NiξO(3 − δ) at temperature between 500 and 900 °C, using impedance spectroscopy at different oxygen partial pressures and...... water vapor pressures, as well as the emf technique. The compounds exhibit p-type conduction in oxidizing atmosphere, and ionic conduction elsewhere. The oxide ion contribution of the conductivity is negligible only for temperatures below 600 °C. The determination of hydration enthalpies, our second...

  14. Studies on Structural and Morphological Properties of Multidoped Ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O2-δ (x=0.2 as Solid Solutions

    Directory of Open Access Journals (Sweden)

    Marija Stojmenović

    2016-01-01

    Full Text Available The nanopowdery solid solutions of multidoped ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O2-δ (x=0.2 with the fluorite type crystal structure of CeO2 were synthesized for the first time. Two synthesis procedures were applied: the modified glycine-nitrate procedure (MGNP method and room temperature self-propagating reaction (SPRT method. All nanopowders were characterized by XRPD analysis, Raman spectroscopy, low temperature nitrogen physisorption, TEM, and SEM methods. According to the XRPD and Raman spectroscopy results, single phase solid solutions of fluorite structure were evidenced regardless of the number of dopants and synthesis procedure. Both XRPD and TEM were analyses evidenced nanometer particle dimensions. The SPRT method results in obtaining sample with higher specific surface area, smaller crystallite and particles sizes, and the same values of the lattice parameter in comparison to pure CeO2. Raman spectroscopy was confirmed to the oxygen vacancies introduced into the ceria lattice when Ce4+ ions were replaced with cations (dopants of lower valence state (3+, which may indicate the potential improvement of ionic conductivity. Additionally, the presence of oxygen vacancies in the lattice ceria, as well as very developed grain boundaries, gives a new possibility for potential application of obtained nanopowders in the area of room temperature ferromagnetism as spintronics.

  15. Studies on Structural and Morphological Properties of Multidoped Ceria Ce 0.8 Nd 0.0025 Sm 0.0025 Gd 0.005 Dy 0.095 Y 0.095 O 2 - δ ( x = 0.2 ) as Solid Solutions

    KAUST Repository

    Stojmenović, Marija

    2016-04-17

    The nanopowdery solid solutions of multidoped ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095 () with the fluorite type crystal structure of CeO2 were synthesized for the first time. Two synthesis procedures were applied: the modified glycine-nitrate procedure (MGNP method) and room temperature self-propagating reaction (SPRT method). All nanopowders were characterized by XRPD analysis, Raman spectroscopy, low temperature nitrogen physisorption, TEM, and SEM methods. According to the XRPD and Raman spectroscopy results, single phase solid solutions of fluorite structure were evidenced regardless of the number of dopants and synthesis procedure. Both XRPD and TEM were analyses evidenced nanometer particle dimensions. The SPRT method results in obtaining sample with higher specific surface area, smaller crystallite and particles sizes, and the same values of the lattice parameter in comparison to pure CeO2. Raman spectroscopy was confirmed to the oxygen vacancies introduced into the ceria lattice when Ce4+ ions were replaced with cations (dopants) of lower valence state (3+), which may indicate the potential improvement of ionic conductivity. Additionally, the presence of oxygen vacancies in the lattice ceria, as well as very developed grain boundaries, gives a new possibility for potential application of obtained nanopowders in the area of room temperature ferromagnetism as spintronics.

  16. Thermal evolution of the crystal structure of proton conducting BaCe0.8Y0.2O3-δ from high-resolution neutron diffraction in dry and humid atmosphere.

    Science.gov (United States)

    Eriksson Andersson, Annika K; Selbach, Sverre M; Grande, Tor; Knee, Christopher S

    2015-06-21

    The crystal structure of the proton conducting perovskite BaCe(0.8)Y(0.2)O(3-δ) (BCY20) has been studied via high-resolution in situ neutron diffraction performed in controlled dry and humid (heavy water) oxygen flow. Two phase transitions, cubic Pm3[combining macron]m→R3[combining macron]c (775 °C)→Imma (250 °C) were observed on cooling from 1000 °C in dry O(2). A significant shift of the phase stability fields was observed on cooling in wet oxygen (pD(2)O ≈ 0.2 atm) with the R3[combining macron]c structure stabilised at 900 °C, and the R3[combining macron]c→Imma transition occurring at 675 °C. On cooling below 400 °C a monoclinic, I2/m, phase started to appear. The structural dependence on hydration level is primarily due to the de-stabilisation of the correlated, octahedra tilts as a consequence of structural relaxation around the oxygen vacancies present in the non-hydrated phase. The tendency of hydrated BaCe(0.8)Y(0.2)O(3-δ) to show octahedral tilting is also found to be enhanced, indicating that the deuteronic (protonic) defects influence the crystal structure, possibly via hydrogen bonding. Stabilisation of the monoclinic I2/m phase is attributed to the structural effect of deuterons that is inferred to increase on cooling as deuterons localise to a greater extent. Changing from wet oxidising (O(2) + D2O(g)) to wet reducing (5% H2 in Ar + D2O(g)) atmosphere did not influence the structure or the phase stability, indicating that Ce(4+) was not reduced under the present conditions. Based on the observed cell volume expansion protonic defects are present in the material at 900 °C at a D(2)O partial pressure of ∼0.2 atm. The origin of the chemical expansion is explained by the effective size of the oxygen vacancy being significantly smaller than the [OD] defect. Rietveld analysis has been used to locate possible sites for the deuterons in the high temperature, R3[combining macron]c and Imma, phases that are most relevant for proton transport

  17. Power-law index and penetration depth of (NdxSmxGd1−2x)Ba2Cu3O7−δ films studied by AC susceptibility

    DEFF Research Database (Denmark)

    Li, Xiaofen; He, Dong; Grivel, Jean-Claude

    2012-01-01

    Superconducting (NdxSmxGd1−2x)Ba2Cu3O7−δ films with x=0, 0.1, 0.25, 0.33 were grown by PLD on STO single crystal substrates. The power-law index n and penetration depth λ are studied by AC susceptibility. During cooling, n in films with x ≠ 0 increases much slower compared with the films with x = 0....... The films with x ≠ 0 also tend to have a longer penetration depth. These properties might be related to the higher possibility for disorder in the mixed (Nd,Sm,Gd)BCO films....

  18. Nitrato-complexes of Y(III), La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III) and Ho(III) with 2-(2'-pyridyl) benzimidazole

    International Nuclear Information System (INIS)

    The nitrato-complexes, [Y(PyBzH)2(NO3)2]NO3.H2O and Nd, Sm, Gd, Tb, Dy, Ho ; n=1-3, m=0-0.5 ; PyBzh=2-(2 -pyridyl)benzimidazole] are formed on interaction of the ligand with metal nitrates in ethanol. The electrical conductance values (116-129 ohm-1cm2mol-1) suggest 1:1 electrolyte-nature of the complexes. Magnetic moment values of Ce(2.53 B.M.), Pr(3.62 B.M.), Nd(3.52 B.M.), Sm(1.70 B.M.), Gd(8.06 B.M.), Tb(9.44 B.M.), Dy(10.56 B.M.) and Ho(10.51 B.M.) in the complexes confirm the terpositive state of the metals. Infrared evidences are obtained for the existance of both coordinated (C2v) and uncoordinated (D3h) nitrate groups. Electronic absorption spectra of Pr(III)-, Nd(III)-, Sm(III)-, Tb(III)-, Dy(III)- and Ho(III)-complexes have been analysed in the light of LSJ terms. (author)

  19. Surface exchange kinetics and chemical diffusivities of BaZr{sub 0.2}Ce{sub 0.65}Y{sub 0.15}O{sub 3−δ} by electrical conductivity relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Dae-Kwang; Jeon, Sang-Yun; Singh, Bhupendra [Ionics Lab, School of Materials Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwang-Ju 500-757 (Korea, Republic of); Park, Jun-Young [Department of Advanced Materials Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Song, Sun-Ju, E-mail: song@chonnam.ac.kr [Ionics Lab, School of Materials Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwang-Ju 500-757 (Korea, Republic of)

    2014-10-15

    Highlights: • Electrical conductivity relaxation in BaCe{sub 0.65}Zr{sub 0.2}Y{sub 0.15}O{sub 3−δ} was monitored. • Monotonic relaxation behavior was observed during oxidation/reduction. • Nonmonotonic twofold relaxation behavior was observed during hydration/dehydration. • Surface exchange coefficients and diffusivities of O and H were calculated. - Abstract: Perovskite-type oxide BaCe{sub 0.65}Zr{sub 0.2}Y{sub 0.15}O{sub 3−δ} (BCZY2015) was synthesized by a solid state reaction method. BCZY2015 samples were characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The time dependent variation in electrical conductivity of BCZY2015 was monitored during the oxidation/reduction in oxygen partial pressure (pO{sub 2}) range of −2.28 ⩽ log (pO{sub 2}/atm) ⩽ −0.68 at a fixed water vapor pressure (pH{sub 2}O), and during the hydration/dehydration in −3.15 ⩽ log (pH{sub 2}O/atm) ⩽ −2.35 range in air. The electrical conductivity showed a monotonic relaxation behavior by the ambipolar diffusion of V{sub o}{sup ··} and OH{sub o}{sup ·} during the oxidation/reduction and the relaxation process was governed by the diffusivity of oxygen (D-tilde{sub vO}). On the other hand, during the hydration/dehydration process, a non-monotonic twofold relaxation behavior was observed due to the decoupled diffusion of H and O components with the mediation of holes, and the conductivity relaxation process was governed by the diffusivities of both H (D-tilde{sub iH}) and O (D-tlde{sub vH}). The values of surface exchange coefficients and diffusivities of oxygen and hydrogen were calculated from Fick’s second law by the nonlinear least squares fitting of the conductivity data, as proposed by Yoo et al. (2008)

  20. Facile synthesis, structural and spectroscopic properties of GdF{sub 3}:Ce{sup 3+}, Ln{sup 3+} (Ln{sup 3+}=Sm{sup 3+}, Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanocrystals with bright multicolor luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Grzyb, Tomasz; Runowski, Marcin; Lis, Stefan, E-mail: blis@amu.edu.pl

    2014-10-15

    Hexagonal gadolinium fluorides doped with Ce{sup 3+} ions and co-doped with Sm{sup 3+}, Eu{sup 3+}, Tb{sup 3+} or Dy{sup 3+} were successfully synthesized via a simple co-precipitation approach, in the presence of glycerin as a capping agent. These fluorides, as solids or in aqueous solutions, showed intense, multicolored luminescence depending on the lanthanide ions used. The structures of the products were confirmed by powder X-ray diffraction (XRD). The morphologies of the synthesized nanophosphors were examined using transmission electron microscopy (TEM). The TEM results showed that the crystallites had shapes that varied with the dopant ion used. The spectroscopic properties: excitation spectra, emission spectra and luminescence decays were recorded and studied in detail. Bright luminescences from all of the products were triggered by effective energy transfer between the ions embedded in their structures. The mechanism for this phenomenon was also proposed. All of the synthesized products formed stable aqueous colloids, exhibiting brightly multicolored luminescence under UV light irradiation. - Highlights: • Hexagonal GdF{sub 3}:Ce{sup 3+}, Ln{sup 3+} nanocrystals were synthesized by a co-precipitation method. • Nanocrystals formed stable water colloids. • Multicolor luminescence under UV light was observed. • Energy transfer mechanism between Gd{sup 3+}, Ce{sup 3+} and Ln{sup 3+} ions was proposed.

  1. Analysis of the melting temperatures of RT2 compounds (MgCu2 structure) (R=Rare Earth, T=Mn,Fe,Co,Ni,Ru,Rh,Pd,Os,Ir,Pt) and RT2X2 compounds (R=La,Ce,Sm,Er; T=Mn,Fe,Co,Ni,Cu,Ru,Rh,Pd,Pt; X=Si,Ge)

    International Nuclear Information System (INIS)

    Physico-chemical analysis techniques, including X-ray phase analysis and differential thermal analysis were employed for the characterisation of compounds including their melting temperature. The melting temperature for 70 RT2X2 compounds has been measured (R=(La, Ce, Sm, Er, Tm), T=(Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Pt), X=(Si, Ge)). It is established, that the compounds CePt2Ge2, LaPt2Si2, LaPt2Ge2 belong to the CaBe2Ge2 structure type (group P4/mmm): LaPt2Si2 (a=0.4280(2) nm, c=0.9831(6) nm); LaPt2Ge2 (a=0.4417(3) nm, c=0.976(2) nm) and CePt2Ge2 (a=0.44033(4) nm, c=0.9808(1)). An empirical model able to describe the melting temperature of Tm of the compounds RT2, RT2X2 with accuracy often better than 5% is presented: Tm=const/V1/3, where the constant factor depends on the type of atoms constituting the compound, and where V is unit cell volume. (orig.)

  2. Synthesis and characterization of novel Ce{sub 0.8}Sm{sub 0.2}Fe{sub 0.9}Ir{sub 0.03}Co{sub 0.07}O{sub 3−δ} perovskite material and possible application as a cathode for low–intermediate temperature SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Njoku, Chima Benjamin; Ndungu, Patrick Gathura, E-mail: ndungup@ukzn.ac.za

    2015-08-15

    Highlights: • Ce{sub 0.8}Sm{sub 0.2}Fe{sub 0.9}Ir{sub 0.03}Co{sub 0.07}O{sub 3−δ} was synthesized using sol–gel methods. • Material was thoroughly characterized using Raman, FTIR, XRD, HRTEM, SEM, and TGA. • Electrochemical performance showed the materials are a promising new cathode material for low temperature SOFC. - Abstract: A novel perovskite material, Ce{sub 0.8}Sm{sub 0.2}Fe{sub 0.9}Ir{sub 0.03}Co{sub 0.07}O{sub 3−δ} was synthesized using a sol–gel technique. The materials were calcined at temperatures of 800 °C, 900 °C, and 1000 °C and then characterized using X-ray diffraction, Raman and infrared spectroscopy, high resolution transmission electron microscopy and scanning electron microscopy (SEM). The particle sizes and crystallite sizes increased with increasing calcination temperature and formed perovskite type materials with some separate magnetite and iridium oxide. The powders were used to assemble button cells using samarium doped ceria as the electrolyte and NiO/SDC as the anode materials. The electrochemical properties were investigated using a Fiaxell open flanges test set-up and a Nuvant™ Powerstat-05 potentiostat/galvanostat. The Ce{sub 0.8}Sm{sub 0.2}Fe{sub 0.9}Ir{sub 0.03}Co{sub 0.07}O{sub 3−δ} cathode material calcined at 1000 °C exhibited the most promising performance, with a maximum power density of 0.400 W/cm{sup 2}, a current density of 0.8 A/cm{sup 2}, and a corresponding area specific resistance of 0.247 Ωcm{sup 2} at 500 °C. The button cells were reasonably stable over15 h.

  3. Structural, thermal and microstructural studies of the proton conductor BaCe0.7Zr0.1Y0.05Zn0.15O3 for IT-SOFCs

    Science.gov (United States)

    Hossain, S.; Radenahmad, N.; Zaini, J. H.; Begum, F.; Azad, A. K.

    2016-03-01

    The specimen of BaCe0.7Zr0.1Y0.05Zn0.15O3, a perovskite-type electrolyte, has been synthesized for application in an anode-supported protonic solid oxide fuel cell by the conventional solid state reaction in air at 1200°C for 12 hours. Structural and thermal characterization has been performed using room temperature X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA). Rietveld analysis of the XRD data has been analyzed by FullProf program and confirmed the single phase of the sample with an orthorhombic crystal structure in the Pbnm space group. To understand the temperature dependent behaviour TG/DTA scan of the precursor was recorded. The TG/DTA scan was performed under constant flow of Argon which exhibits a gradual weight loss up to 900oC. The SEM image of the pellet surface of the sample shows that the sample sintered at 1200oC was dense and suitable to use as electrolyte in solid oxide fuel cells (SOFCs).

  4. Crystal grains alignment of SmBCO film by advanced TFA-MOD method

    International Nuclear Information System (INIS)

    We grew SmBa2Cu3O7-y (SmBCO) films on LaAlO3 (LAO) single crystalline substrates by an advanced TFA-MOD method and discussed the effects of process conditions such as oxygen partial pressure in the crystallization step on the crystal grains alignment of SmBCO film. Oxygen partial pressure affected strongly on the orientation of SmBCO film. Formation of a-axis crystal grains of the SmBCO was suppressed, and, at the same time, c-axis crystal grains of the SmBCO increased with decreasing the oxygen concentration

  5. Fabrication of electrolyte-free fuel cell with Mg0.4Zn0.6O/Ce0.8Sm0.2O2-delta-Li0.3Ni0.6Cu0.07Sr0.03O2-delta layer

    OpenAIRE

    Hu, Huiqing; Lin, Qizhao; Zhu, Zhigang; Zhu, Bin; Liu, Xianrong

    2014-01-01

    Electrolyte-free fuel cell (EFFC) which holds the similar function with the traditional solid oxide fuel cell (SOFC) but possesses a completely different structure, has draw much attention during these years. Herein, we report a complex of MZSDC LNCS (Mg0.4Zn0.6O/Ce0.8Sm0.2O2-delta-Li0.3Ni0.6Cu0.07Sr0.03O2-delta) for EFFC that demonstrates a high electrochemical power output of about 600 mW cm(-2) at 630 degrees C. The co-doped MZSDC is synthesized by a co-precipitation method. Semiconductor ...

  6. Simulated monazite crystalline wasteform La0.4Nd0.1Y0.1Gd0.1Sm0.1Ce0.1Ca0.1(P0.9Mo0.1O4): Synthesis, phase stability and chemical durability study

    International Nuclear Information System (INIS)

    Highlights: • Hexavalent molybdenum and selected lanthanides were immobilized into monazite structure at low temperature. • The wasteform has been characterized by powder XRD, FTIR, SEM-EDX and XPS analysis. • Immobilization of molybdenum was proved by energy dispersive X-ray analysis. • Chemical durability of the wasteform was studied by dynamic Soxhlet test. • Polymer–ceramic composite approach reduced the leaching of molybdenum from monazite lattice. - Abstract: In this work, incorporation of hexavalent molybdenum and selected trivalent lanthanides using divalent calcium as charge compensator into the monazite structure were studied. Rare earth substituted phosphomolybdates of the formula REE0.9Ca0.1P0.9Mo0.1O4 (REE = Ce, Nd, Sm, Gd) and the wasteform La0.4Nd0.1Y0.1Gd0.1Sm0.1Ce0.1Ca0.1P0.9Mo0.1O4 were synthesized by simple solution route. The prepared compounds were characterized by powder X-ray diffraction, Fourier transformed infrared spectra, thermogravimetric analysis, energy dispersive X-ray analysis and scanning electron microscopic techniques. Chemical durability of the wasteform was studied by dynamic MCC-5 test for a period of one month. Normalized elemental mass loss and leach rate of molybdenum was found to be in the order of 103 g/m2 and 103–101 g/m2/d respectively. Polymer-monazite composite wasteform was prepared to control the leaching of molybdenum. The composite approach reduced molybdenum leach rate order from 101 to 10−4 g/m2/d

  7. Study on new BaCe0.7In0.3O3−δ–Gd0.1Ce0.9O2−δ composite electrolytes for intermediate-temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Highlights: • New BCI–GDC composite electrolytes were synthesized using a one-step method for SOFCs. • The sintering temperature decreases as the BCI content increases. • The conductivity and OCV values enhanced as the GDC content increases. • The possible interface effects between BCI and GDC were analyzed. - Abstract: New mixed ionic conductors, BaCe0.7In0.3O3−δ–Gd0.1Ce0.9O2−δ (BCI–GDC, weight ratio, 3:7, 5:5 and 7:3), were synthesized via a one-step citric acid–nitrate gel combustion method as electrolyte materials for solid oxide fuel cells (SOFCs). X-ray diffraction patterns of BCI–GDC indicated that there was no impurity phase formed after sintering at high temperature up to 1400 °C. Scanning electron microscopic study of BCI–GDC depicted dense grain morphology. Single fuel cells were prepared and the corresponding electrochemical performances were tested. The sintering temperature of the dense composite electrolyte membranes decrease as the BCI content increases because of the sintering aids of In element. All samples with the composite electrolyte showed higher open circuit voltage (OCV) values than the single phase GDC. In addition, Electrical conductivity of the composite electrolyte under different atmospheres at different temperatures confirmed that the BCI–GDC exhibited high mixed oxygen ionic and protonic conduction. The test results indicated that the conductivity and OCV values of the composite electrolyte enhanced as the GDC content increases, and the optimum performance was found to be BCI3–GDC7 compared with the pure BCI and GDC electrolyte. The possible interface effects were suggested to explain this phenomenon. Our results not only provide one new promising composite electrolyte material for intermediate-temperature SOFCs but the composition dependence can actually provide a guide for the material design, optimization

  8. A magnetic study of ThCr2Si2-type pseudo-ternary RMn1.5T0.5Ge2 compounds. (R=Y,Ce-Sm,Gd-Ho; T=Fe,Cu)

    International Nuclear Information System (INIS)

    We report on bulk magnetization measurements performed on ThCr2Si2-type RMn1.5T0.5Ge2 compounds (R=Y, La-Nd, Sm, Gd-Ho; T=Cu, Fe). These pseudo-ternary compounds display largely correlated variations of their magnetic transition temperatures. This phenomenon might be related to magnetic properties based on competing in-plane and inter-plane Mn-Mn interactions. The RMn1.5Cu0.5Ge2 compounds are characterized by relatively large magnetocrystalline anisotropy. (orig.)

  9. Thermoelectric properties of hot-pressed Tl{sub 9}LnTe{sub 6} (Ln = La, Ce, Pr, Nd, Sm, Gd, Tb) and Tl{sub 10−x}La{sub x}Te{sub 6} (0.90 ⩽ x ⩽ 1.05)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Quansheng; Kleinke, Holger, E-mail: kleinke@uwaterloo.ca

    2015-05-05

    Highlights: • Electrical conductivity and thermal conductivity increase with the Ln series from the left to the right. • Seebeck coefficient and figure-of-merit increase with the Ln series from the right to the left. • As for Tl{sub 10−x}La{sub x}Te{sub 6}, the best properties were found when x = 1. • The highest figure-of-merit of these materials is zT{sub max} = 0.57 at 600 K, realized for Tl{sub 9}LaTe{sub 6}. • This constitutes a huge improvement over the cold-pressed and sintered materials with their zT{sub max} = 0.21. - Abstract: In the first part of this work, thallium lanthanide tellurides with composition Tl{sub 9}LnTe{sub 6} (Ln = La, Ce, Pr, Nd, Sm, Gd, Tb) have been prepared and their high temperature electrical and thermal transport properties investigated. Nearly single phase samples were obtained. Rietveld refinement results showed that Tl{sub 9}CeTe{sub 6} had an exceptionally small unit cell volume of 1033 Å{sup 3}. The electrical conductivity and thermal conductivity increased across the lanthanide series from La to Tb. On the other hand, the Seebeck coefficient values decreased with Ln varying from La to Tb. Tl{sub 9}SmTe{sub 6} or Tl{sub 9}GdTe{sub 6} constituted an exception, as the Seebeck coefficient of Tl{sub 9}SmTe{sub 6} was smaller than that of Tl{sub 9}GdTe{sub 6}. Tl{sub 9}LaTe{sub 6} has the largest figure-of-merit of this series. Thereafter, Tl{sub 10−x}La{sub x}Te{sub 6} samples were prepared with x = 0.90, 0.95, 1.00, 1.05, 1.10, aiming toward higher zT through composition optimization and expanding of the measurement temperature range. With the increasing La content, the unit cell volume increased, while the electrical conductivity, thermal conductivity and lattice thermal conductivity decreased, and the Seebeck coefficient increased. The highest zT = 0.57 was observed for Tl{sub 9}LaTe{sub 6} at 600 K.

  10. Crystal structure and phase transition studies in perovskite-type oxides using powder-diffraction techniques and symmetry-mode analysis : SrLnMRuO6 (Ln=La,Pr,Nd; M=Zn,Co,Mg,Ni,Fe) and ALn2CuTi2O9 (A=Ca,Ba; Ln=La,Pr,Nd,Sm)

    OpenAIRE

    Iturbe Zabalo, Edurne

    2013-01-01

    La tesis se ha centrado en la síntesis y caracterización estructural de materiales tipo perovskita: SrLnMRuO6 (Ln=La,Pr,Nd; M=Zn,Co,Mg,Ni,Fe) y ALn2CuTi2O9 (A=Ca,Ba; Ln=La,Pr,Nd,Sm). El estudio de las estructuras de los materiales se ha realizado mediante el análisis de los patrones de difracción en polvo de rayos-X, sincrotrón y/o neutrones. En el refinamiento por el método de Rietveld de las estructuras se han sustituido las coordenadas atómicas (el método más común), por coordenadas colect...

  11. $\\gamma$-soft $^{146}$Ba and the role of non-axial shapes at N ~ 90

    CERN Document Server

    Mitchell, A J; McCutchan, E A; Albers, M; Ayangeakaa, A D; Bertone, P F; Carpenter, M P; Chiara, C J; Chowdhury, P; Clark, J A; Copp, P; David, H M; Deo, A Y; DiGiovine, B; D'Olympia, N; Dungan, R; Harding, R D; Harker, J; Hota, S S; Janssens, R V F; Kondev, F G; Liu, S H; Ramayya, A V; Rissanen, J; Savard, G; Seweryniak, D; Shearman, R; Sonzogni, A A; Tabor, S L; Walters, W B; Wang, E; Zhu, S

    2015-01-01

    Low-spin states in the neutron-rich, N = 90 nuclide $^{146}$Ba were populated following $\\beta$-decay of $^{146}$Cs, with the goal of clarifying the development of deformation in Ba isotopes through delineation of their non-yrast structures. Fission fragments of $^{146}$Cs were extracted from a 1.7-Ci $^{252}$Cf source and mass-selected using the CARIBU facility. Low-energy ions were deposited at the center of a box of thin $\\beta$ detectors, surrounded by a high-efficiency HPGe array. The new $^{146}$Ba decay scheme now contains 31 excited levels extending up to ~2.5 MeV excitation energy, double what was previously known. These data are compared to predictions from the Interacting Boson Approximation (IBA) model. It appears that the abrupt shape change found at N = 90 in Sm and Gd is much more gradual in Ba and Ce, due to an enhanced role of the $\\gamma$ degree of freedom.

  12. Study on new BaCe{sub 0.7}In{sub 0.3}O{sub 3−δ}–Gd{sub 0.1}Ce{sub 0.9}O{sub 2−δ} composite electrolytes for intermediate-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fengguang; Dang, Junjie; Hou, Jie; Qian, Jing; Zhu, Zhiwen; Wang, Zhongtao [CAS Key Laboratory of Materials for Energy Conversion, Department of Material Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Liu, Wei, E-mail: wliu@ustc.edu.cn [CAS Key Laboratory of Materials for Energy Conversion, Department of Material Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2015-08-05

    Highlights: • New BCI–GDC composite electrolytes were synthesized using a one-step method for SOFCs. • The sintering temperature decreases as the BCI content increases. • The conductivity and OCV values enhanced as the GDC content increases. • The possible interface effects between BCI and GDC were analyzed. - Abstract: New mixed ionic conductors, BaCe{sub 0.7}In{sub 0.3}O{sub 3−δ}–Gd{sub 0.1}Ce{sub 0.9}O{sub 2−δ} (BCI–GDC, weight ratio, 3:7, 5:5 and 7:3), were synthesized via a one-step citric acid–nitrate gel combustion method as electrolyte materials for solid oxide fuel cells (SOFCs). X-ray diffraction patterns of BCI–GDC indicated that there was no impurity phase formed after sintering at high temperature up to 1400 °C. Scanning electron microscopic study of BCI–GDC depicted dense grain morphology. Single fuel cells were prepared and the corresponding electrochemical performances were tested. The sintering temperature of the dense composite electrolyte membranes decrease as the BCI content increases because of the sintering aids of In element. All samples with the composite electrolyte showed higher open circuit voltage (OCV) values than the single phase GDC. In addition, Electrical conductivity of the composite electrolyte under different atmospheres at different temperatures confirmed that the BCI–GDC exhibited high mixed oxygen ionic and protonic conduction. The test results indicated that the conductivity and OCV values of the composite electrolyte enhanced as the GDC content increases, and the optimum performance was found to be BCI3–GDC7 compared with the pure BCI and GDC electrolyte. The possible interface effects were suggested to explain this phenomenon. Our results not only provide one new promising composite electrolyte material for intermediate-temperature SOFCs but the composition dependence can actually provide a guide for the material design, optimization.

  13. Influence of foreign cations (Zr4+, La3+, Pr3+ and Sm3+) on CuO-CeO2: microwave induced solution combustion synthesis, characterization and CO oxidation activity

    International Nuclear Information System (INIS)

    Carbon monoxide treatment by catalytic oxidation, such as water-gas-shift reaction (WGSR), preferential oxidation of CO in H2 rich streams (PROX) and its simple oxidation have received a great attention by the scientific community. The noble metal-based nanocomposites have proven to be the highly effective candidates towards the CO oxidation. However, some of the disadvantages associated with the noble metals leads to an extensive search for alternative materials. In recent years, copper-cerium based mixed oxides have received much attention because they are inexpensive, environmentally benign and can be prepared easily. Therefore, the present study was aimed at developing a new class of copper promoted metal doped CeO2 catalysts using microwave-assisted combustion method

  14. Structural studies of type N superconductive compounds: R{sub 2-x}Ce{sub x}CuO{sub 4{+-}{delta}} (R = Gd, Eu, Sm, Nd, Pr); influences of chemical treatments on physical properties; Etudes structurales des composes supraconducteurs de type N: R{sub 2-x}Ce{sub x}CuO{sub 4{+-}{delta}} (R = Gd, Eu, Sm, Nd, Pr); influences des traitements chimiques sur les proprietes physiques

    Energy Technology Data Exchange (ETDEWEB)

    Vigoureux, P.

    1995-06-01

    Different chemical treatments of R{sub 2-x}Ce{sub x}CuO{sub 4{+-}{delta}} compounds monocrystals (gadolinium, europium, samarium, neodymium and praseodymium cuprates) modify their physical properties especially their superconductive properties. The presented chemical treatments are: the substitution of the trivalent rare earth element R by an other trivalent lanthanide, its substitution by tetravalent cerium, and heat treatment under low oxygen pressure. After these chemical treatments, structural modifications are observed by neutrons and X-rays diffraction, and allow to precise their actions: size effect of the rare earth element on the deformation of the CuO{sub 2} planes, links between deformation and superconductivity and magnetic properties. (A.B.). 394 refs/.

  15. Syngas production on a symmetrical solid oxide H2O/CO2 co-electrolysis cell with Sr2Fe1.5Mo0.5O6-Sm0.2Ce0.8O1.9 electrodes

    Science.gov (United States)

    Wang, Yao; Liu, Tong; Fang, Shumin; Chen, Fanglin

    2016-02-01

    High temperature H2O/CO2 co-electrolysis process is performed on the symmetrical Sr2Fe1.5Mo0.5O6(SFM)-Sm0.2Ce0.8O1.9(SDC)/La0.8Sr0.2Ga0.87Mg0.13O3 (LSGM)/SFM-SDC cells, which exhibit excellent electrochemical performance with the current density of -734 mAcm-2 at 1.3 V and the interfacial polarization resistance of 0.48 Ωcm2 at 850 °C. Enhanced co-electrolysis kinetics are obtained with increasing the operating temperature and applied cell voltage. Synthesis gas of H2 and CO is produced by H2O splitting and reverse water gas shift (RWGS) reaction on the SFM-SDC/LSGM/SFM-SDC co-electrolysis cells. Effects of temperature and electrolysis current on the produced gas fraction are predicted using the chemical equilibrium co-electrolysis model. High CO2 conversion rate and ideal H2 to CO ratio of approximately 2 can be achieved by adjusting appropriate inlet gas fraction, temperature and electrolysis current. The SFM-SDC/LSGM/SFM-SDC cell shows a relative stable cell voltage in the 103-h galvanostatic test.

  16. Recent progress on compositional nanostripes of REBa2Cu3O7-δ (RE = Sm,Eu,Gd) superconductors

    International Nuclear Information System (INIS)

    We characterized ordered compositional fluctuation in high-quality SmBa2Cu3O7-δ, (Sm0.5Eu0.5)Ba2Cu3O7-δ, and (Sm0.33Eu0.33Gd0.33)Ba2Cu3O7-δ superconductors by atomic force microscopy, scanning tunnelling microscopy, and transmission electron microscopy. The presence of nanostripes along the crystalline c direction was confirmed in SmBa2Cu3O7-δ single crystals and in melt-processed (Sm0.5Eu0.5)Ba2Cu3O7-δ, (Sm0.33Eu0.33Gd0.33)Ba2Cu3O7-δ materials. Meanwhile, thickness fringes originating from the twin boundaries were also identified in some samples; these could be clearly separated from real nanostripes with sample tilting. Compositional nanostripes displayed spatial variation in both shape and wavelength over a large area of RE-Ba-Cu-O single domains. The origin of the nanostripe is discussed in the context of the competitive growth mechanism of RE1+xBa2-xCu3O7-δ solid solution

  17. Effect of samarium doping on electrodeposited CeO2 thin film

    International Nuclear Information System (INIS)

    Samarium-doped cerium oxide (CeO2:Sm) and undoped cerium oxide (CeO2) thin films were fabricated by electrodeposition on biaxially textured Ni-3% W substrates. The electrodeposited layers were annealed for several hours at temperatures ranging from 910 to 980 C. The resulting crystalline films were investigated by XRD and SEM. The CeO2 crystallite size was correlated to the formation of microcrack in CeO2 and CeO2:Sm using the Scherrer equation of XRD analysis. Crack-free films with an average grain size of about 28 nm were obtained for both Ce0.92Sm0.08O2-δ and Ce0.8Sm0.2O2-δ films. Sm doping strongly affects the crystallite size, crystal structure, texture, and crack formation in ceria films. The lattice parameter a increases and crystallite size is reduced with increased Sm doping. All electrodeposited films are highly biaxially textured. When compared to Ni-based substrates, improvements in the out-of-plane and in-plane texture in ceria- and Sm-doped ceria films were achieved. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Draft Genome Sequences of Stenotrophomonas maltophilia Strains Sm32COP, Sm41DVV, Sm46PAILV, SmF3, SmF22, SmSOFb1, and SmCVFa1, Isolated from Different Manures in France.

    Science.gov (United States)

    Bodilis, Josselin; Youenou, Benjamin; Briolay, Jérome; Brothier, Elisabeth; Favre-Bonté, Sabine; Nazaret, Sylvie

    2016-01-01

    Stenotrophomonas maltophilia is a major opportunistic human pathogen responsible for nosocomial infections. Here, we report the draft genome sequences of Sm32COP, Sm41DVV, Sm46PAILV, SmF3, SmF22, SmSOFb1, and SmCVFa1, isolated from different manures in France, which provide insights into the genetic determinism of intrinsic or acquired antibiotic resistance in this species. PMID:27540065

  19. γ -soft 146Ba and the role of nonaxial shapes at N ≈90

    Science.gov (United States)

    Mitchell, A. J.; Lister, C. J.; McCutchan, E. A.; Albers, M.; Ayangeakaa, A. D.; Bertone, P. F.; Carpenter, M. P.; Chiara, C. J.; Chowdhury, P.; Clark, J. A.; Copp, P.; David, H. M.; Deo, A. Y.; DiGiovine, B.; D'Olympia, N.; Dungan, R.; Harding, R. D.; Harker, J.; Hota, S. S.; Janssens, R. V. F.; Kondev, F. G.; Liu, S. H.; Ramayya, A. V.; Rissanen, J.; Savard, G.; Seweryniak, D.; Shearman, R.; Sonzogni, A. A.; Tabor, S. L.; Walters, W. B.; Wang, E.; Zhu, S.

    2016-01-01

    Low-spin states in the neutron-rich, N =90 nuclide 146Ba were populated following β decay of 146Cs, with the goal of clarifying the development of deformation in barium isotopes through delineation of their nonyrast structures. Fission fragments of 146Cs were extracted from a 1.7-Ci 252Cf source and mass selected using the CAlifornium Rare Ion Breeder Upgrade (CARIBU) facility. Low-energy ions were deposited at the center of a box of thin β detectors, surrounded by a highly efficient high-purity Ge array. The new 146Ba decay scheme now contains 31 excited levels extending up to ˜2.5 MeV excitation energy, double what was previously known. These data are compared to predictions from the interacting boson approximation (IBA) model. It appears that the abrupt shape change found at N =90 in Sm and Gd is much more gradual in Ba and Ce, due to an enhanced role of the γ degree of freedom.

  20. Impedance spectroscopy studies on (Na0.5Bi0.5)0.94Ba0.06TiO3 + 0.3 wt% Sm2O3 + 0.25 wt% LiF lead-free piezoelectric ceramics

    Indian Academy of Sciences (India)

    N Zidi; A Chaouchi; S D’Astorg; M Rguiti; C Courtois

    2015-06-01

    The a.c. complex impedance spectroscopy technique was used to obtain the electrical parameters of (Na0.5Bi0.5)0.94Ba0.06TiO3 +0.3 wt% Sm2O3 +0.25 wt% LiF lead-free ceramics in a wide frequency range at different temperatures. These samples were prepared by a high-temperature solid-state reaction technique and their single phase formation was confirmed by the X-ray diffraction technique. Dielectric studies exhibit a diffuse phase transition characterized by a temperature and frequency dispersion of permittivity, and this relaxation has been modelled using the modified Curie–Weiss law. The variation of imaginary part (″) of impedance with frequency at various temperatures shows that the ″ values reach a maxima peak (″max) above 400° C. The appearance of single semicircle in the Nyquist plots (″ vs. ′) pattern at high temperatures suggests that the electrical process occurring in the material has a relaxation process possibly due to the contribution for bulk material only. The bulk resistance of the material decreases with rise in temperatures similar to that of a semiconductor, and the Nyquist plot showed the negative temperature coefficient of resistance (NTCR) character of these materials. The frequencies, thermal effect on a.c. conductivity and activation energy have been assessed.

  1. Properties of the (Sm sub 0 sub . sub 3 sub 3 Eu sub 0 sub . sub 3 sub 3 Gd sub 0 sub . sub 3 sub 3)Ba sub 2 Cu sub 3 O sub y superconductor prepared by different processes in air

    CERN Document Server

    Giovannelli, F; Monot-Laffez, I

    2003-01-01

    Bars and pellets of the (Sm sub 0 sub . sub 3 sub 3 Eu sub 0 sub . sub 3 sub 3 Gd sub 0 sub . sub 3 sub 3)Ba sub 2 Cu sub 3 O sub x superconductor were processed in air, using the floating zone method and the top-seeded melt-textured growth method, respectively. The samples were prepared using different experimental conditions, i.e. maximal processing temperature, translation rate or cooling rate. Their physical properties and their microstructure were studied. All the samples exhibit a satisfying superconducting transition whereas the critical current density greatly depends on the processing parameters. The sample prepared by the floating zone method at 1070 deg C with a translation rate of 2 mm h sup - sup 1 exhibits a very high J sub c value of 70000 A cm sup - sup 2 in the self-field and more than 30000 A cm sup - sup 2 at 1.7 T. The pellet processed at 1080 deg C with a cooling rate of 2 deg C h sup - sup 1 has a high J sub c reaching about 56000 A cm sup - sup 2 in the self-field and more than 32000 A ...

  2. Ternary rare-earth titanium antimonides: Phase equilibria in the RE-Ti-Sb (RE=La, Er) systems and crystal structures of RE2Ti7Sb12 (RE=La, Ce, Pr, Nd) and RETi3(SnxSb1-x)4 (RE=Nd, Sm)

    International Nuclear Information System (INIS)

    Investigations on phase relationships and crystal structures have been conducted on several ternary rare-earth titanium antimonide systems. The isothermal cross-sections of the ternary RE-Ti-Sb systems containing a representative early (RE=La) and late rare-earth element (RE=Er) have been constructed at 800 deg. C. In the La-Ti-Sb system, the previously known compound La3TiSb5 was confirmed and the new compound La2Ti7Sb12 (own type, Cmmm, Z=2, a=10.5446(10) A, b=20.768(2) A, and c=4.4344(4) A) was discovered. In the Er-Ti-Sb system, no ternary compounds were found. The structure of La2Ti7Sb12 consists of a complex arrangement of TiSb6 octahedra and disordered fragments of homoatomic Sb assemblies, generating a three-dimensional framework in which La atoms reside. Other early rare-earth elements (RE=Ce, Pr, Nd) can be substituted in this structure type. Attempts to prepare crystals in these systems through use of a tin flux resulted in the discovery of a new Sn-containing pseudoternary phase RETi3(SnxSb1-x)4 for RE=Nd, Sm (own type, Fmmm, Z=8; a=5.7806(4) A, b=10.0846(7) A, and c=24.2260(16) A for NdTi3(Sn0.1Sb0.9)4; a=5.7590(4) A, b=10.0686(6) A, and c=24.1167(14) A for SmTi3(Sn0.1Sb0.9)4). Its structure consists of double-layer slabs of Ti-centred octahedra stacked alternately with nets of the RE atoms; the Ti atoms are arranged in kagome nets. - Graphical abstract: La2Ti7Sb12 contains sectioned layers consisting of Ti-centred octahedra linked by corner- and face-sharing

  3. Thermophysical properties of Sm2(Zr1-xCex)2O7 ceramics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hongsong; SUN Kun; XU Qiang; WANG Fuchi; LIU Ling; WEI Yuan; CHEN Xiaoge

    2009-01-01

    Sm2(Zr1-xCex)2O7 (x = 0.1, 0.2, and 0.3) ceramics were prepared by solid reaction method at 1600~C for 10 h using Sm2O3, ZrO2, and CeO2as starting reactants. The phase compositions, microstructures, thermal expansion coefficients, and partial thermal conductivities of these materials were investigated. X-ray diffraction (XRD) results reveal that Sm2(Zr0.gCe0.t~zO7 with pyrochiore structure and Sm2(Zr1-xCex)2O7 (x = 0.2 and 0.3) with fluorite structure were synthesized, and scanning electrical microscopy (SEM) images show that the microstructures of these products are very dense. The linear thermal expansion coefficients increase with increasing temperature in the temperature range from ambient to 1200℃, and the thermal expansion coefficients increase with increasing content of doped CeO2. The thermal conductivities of Sm2(Zr0.8Ce0.2)2O7 and Sm2(Zr0.7Ce0.3)2O7 decrease gradually with an increase in temperature. These results show that the synthesized ceramic materials can be explored as novel prospective candidate materials for use in new thermal barrier coating systems in the future.

  4. Performance of Composite Cathode Sr0.95Ti0.05Co0.95O3-δ-Sm0.2Ce0.8O1.9 Used in Intermediate Temperature SOFCs%新型复合阴极 Sr0.95Ti0.05Co0.95O3-δ-Sm0.2Ce0.8O1.9在中低温固体氧化物燃料电池中的性能

    Institute of Scientific and Technical Information of China (English)

    余良浩; 王晓晴; 林彬; 田冬; 卢肖永; 顾庆文; 陈永红

    2015-01-01

    采用柠檬酸自蔓延燃烧法合成了 Sr0.95Ti0.05Co0.95O3−δ(STC)阴极粉体和 Sm0.2Ce0.8O1.9(SDC)电解质粉体,将 STC 与SDC 粉体按质量比7:3混合得到复合阴极。通过 X 射线衍射(XRD)、直流四端子法和热膨胀仪表征了样品的化学相容性、电导率和热膨胀系数。XRD 表明,STC 在900℃能够得到立方纯钙钛矿结构,复合阴极 STC−SDC 在工作温度区间内具有很好的化学相容性;在650℃空气气氛下 STC−SDC 与 SDC 之间的界面极化阻抗仅为0.05Ω·cm2。制备了阳极支持型(NiO-SDC│SDC│STC−SDC)单电池,在450~650℃范围内以湿润的 H2(3%水蒸汽)为燃料气,空气为氧化剂测试了单电池的性能。结果表明:阳极支撑的单电池共烧1350℃可以得到致密的电解质层和多孔的电极,而且650℃时单电池开路电压0.82 V,最大输出功率为721 mW/cm2。结果预示,在以 SDC 为电解质的中低温固体氧化物燃料电池(IT-SOFC)中,STC-SDC 是一个很有前途的复合阴极材料。%A cathode powder of Sr0.95Ti0.05Co0.95O3−δ(STC) and an electrolyte powder of Sm0.2Ce0.8O1.9 (SDC) were synthesized by a citric acid-nitrates self-propagating combustion method. The composite-cathode was obtained by mixing the STC and SDC powders in a mass ratio of 7:3. The chemical compatibility, electrical conductivity and thermal expansion coefficient of the composite cathode were characterized by X-ray diffraction(XRD), direct current four-terminal method and thermal dilatometer, respectively. The XRD results show that a pure cubic STC perovskite phase can be obtained at 900 and℃ no second phase is formed in the composite cathode at the operating temperature. The polarization resistance of the electrode is only 0.05 Ω·cm2 at 650 ℃. The anode-supported solid oxide fuel cells of NiO-SDC│SDC│STC−SDC were fabricated. The electrochemical performances were examined at 450−650 ℃ with humidified hydrogen (about 3

  5. Semi-empirical calculations of radiative rates for parity-forbidden transitions within the 4f2 configuration of Ba-like ions La+, Ce2+, Pr3+ and Nd4+ and 4f12 configuration of Dy-like Yb4+

    International Nuclear Information System (INIS)

    The experimental free ion 4f12 energy levels for Yb4+ have been fitted to the standard f-shell free ion Hamiltonian, which includes the major electrostatic and spin–orbit terms as well as various minor contributions like two-body, spin–spin, spin–other-orbit and electrostatically correlated spin–orbit interactions. Then, the fitted values of free ion parameters and the corresponding eigenstates are used to calculate the oscillator strengths for all absorption transitions and the spontaneous emission rates for all magnetic dipole and electric quadrupole transitions, originating from levels of the 4f2 configuration in Ba-like ions La+, Ce2+, Pr3+ and Nd4+, and the conjugate electron configuration 4f12 in Dy-like Yb4+ ions. Our calculated results are also compared with some findings available in the literature. (paper)

  6. The WWR-SM-20 research reactor

    International Nuclear Information System (INIS)

    In this paper the design features and experimental capabilities of the WWR-SM-20 research reactor are described. The reactor uses fuel assemblies consisting of six coaxial fuel tubes with a square cross-section. IRT-3M fuel assemblies can be used with both 90% enriched and 36% enriched uranium. The main characteristics of the IRT-3M fuel assemblies are given, as are the technical and physical parameters of the WWR-SM-20 reactor. The core can hold up to ten ampoule-type channels with a diameter of up to 68 mm. For irradiation purposes, up to 22 26-mm-diameter channels in the fuel assemblies, and up to 48 42-mm-diameter channels in the beryllium blocks of the reflector can be used. In the graphite blanket between the horizontal channels, channels with a diameter of up to 130 mm can be used. The thermal neutron flux density has a maximum value of 1.5 X 1018 m-2 · s-1 in the core and 2.3 X 1018 m-2 · s-1 in the reflector, and the fast neutron flux density (cE > 0.821 MeV) a maximum of 1.9 X 1018 m-2 · s-1. A number of design features have been incorporated in the WWR-SM-20 reactor to make it effectively safe

  7. Sm Transition Probabilities and Abundances

    OpenAIRE

    Lawler, J. E.; Hartog, E.A. den; Sneden, C.; Cowan, J. J.

    2005-01-01

    Radiative lifetimes, accurate to +/- 5%, have been measured for 212 odd-parity levels of Sm II using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier-transform spectrometry to determine transition probabilities for more than 900 lines of Sm II. This work is the largest-scale laboratory study to date of Sm II transition probabilities using modern methods. This improved data set has been used to determine a new solar photospheric Sm abundanc...

  8. Ternary aurides RE{sub 4}Mg{sub 3}Au{sub 10} (RE = La, Ce, Pr) and RE{sub 4}Cd{sub 3}Au{sub 10} (RE = Y, La-Nd, Sm, Gd-Dy). Ordering variants of the Zr{sub 7}Ni{sub 10} type

    Energy Technology Data Exchange (ETDEWEB)

    Johnscher, Michael; Block, Theresa; Niehaus, Oliver; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2015-07-01

    The intermetallic gold compounds RE{sub 4}Mg{sub 3}Au{sub 10} (RE = La, Ce, Pr) and RE{sub 4}Cd{sub 3}Au{sub 10} (RE = Y, La-Nd, Sm, Gd-Dy) were obtained from the elements through high-frequency melting in sealed niobium tubes and subsequent annealing in a muffle furnace. The new aurides crystallize with the Ca{sub 4}In{sub 3}Au{sub 10}-type structure. They were characterized through Guinier powder patterns. The structures of Pr{sub 4.46}Cd{sub 2.54}Au{sub 10} and Tb{sub 4.38}Cd{sub 2.62}Au{sub 10} were refined from single crystal X-ray diffractometer data: Cmce, a = 1396.73(6), b = 1009.38(3), c = 1019.51(3) pm, wR2 = 0.0423, 1281 F{sup 2} values, 47 variables for Pr{sub 4.46}Cd{sub 2.54}Au{sub 10} and a = 1362.68(3), b = 995.52(4), c = 1003.79(3) pm, wR2 = 0.0381, 1594 F{sup 2} values, F{sup 2} 47 variables for Tb{sub 4.38}Cd{sub 2.62}Au{sub 10}. The 8e sites of both crystals show substantial Cd/Pr respectively Cd/Tb mixing, indicating small homogeneity ranges for all RE{sub 4+x}Mg{sub 3-x}Au{sub 10} and RE{sub 4+x}Cd{sub 3-x}Au{sub 10} aurides. The gold atoms in these aurides form a pronounced two-dimensional substructure (275-327 pm Au-Au in Pr{sub 4.46}Cd{sub 2.54}Au{sub 10}) which encages the Mg1/Cd1 (coordination number 8) and RE2 (coordination number 11) atoms. These blocks are separated by the Mg2/Cd2 and RE1 atoms with an intergrowth of Mg2/Cd2 rate at Au{sub 8} and RE1 rate at Au{sub 10} polyhedra. Temperature dependent magnetic susceptibility and specific heat measurements of Tb{sub 4}Cd{sub 3}Au{sub 10} have shown antiferromagnetic ordering at a Neel temperature of 12(1) K.

  9. Nonisothermal Kinetice of Dehydration Process of [Sm(m-CIBA)3phen]2·2H2O and[Sm(p-CIBA)3phen]2·2H2O

    Institute of Scientific and Technical Information of China (English)

    REN Ning; WANG Xie; ZHANG Jie; ZHANG Jian-jun; XU Su-ling; ZHANG Hai-yan

    2008-01-01

    Compounds[Sm(m-CIBA)3phen]2·2H2O and[Sm(p-ClBA)3phen]2·2H2O(m-ClBA=m-chlorobenzoate,PClBA=p-chlorobenzoate,phen=1,10-phenanthroline)were prepared.The dehydration processes and kinetics of these compounds were studied from the analysis of the DSC curves using a method of processing the data of thermal analysis kinetics.The Arrhenius equation for the dehydration process can be expressed as lnk=38.65-243.90x103|RT for and△S≠ of dehydration reaction for the title compounds are determined,respectively.

  10. Luminescence properties of the Sm-doped borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kindrat, I.I. [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland); Padlyak, B.V., E-mail: B.Padlyak@if.uz.zgora.pl [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland); Vlokh Institute of Physical Optics, 23 Dragomanov Street, 79-005 Lviv (Ukraine); Drzewiecki, A. [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland)

    2015-10-15

    The optical absorption and photoluminescence (emission and excitation) spectra as well as decay kinetics of a series of the Sm-doped glasses with Li{sub 2}B{sub 4}O{sub 7}, LiKB{sub 4}O{sub 7}, CaB{sub 4}O{sub 7}, and LiCaBO{sub 3} compositions were investigated and analysed. The Li{sub 2}B{sub 4}O{sub 7}:Sm, LiKB{sub 4}O{sub 7}:Sm, CaB{sub 4}O{sub 7}:Sm, and LiCaBO{sub 3}:Sm glasses of high optical quality have been obtained from the corresponding polycrystalline compounds in the air atmosphere, using a standard glass technology. On the basis of electron paramagnetic resonance (EPR) and optical spectra analysis it was shown that the samarium impurity is incorporated into the glass network as Sm{sup 3+} (4f{sup 5}, {sup 6}H{sub 5/2}) ions, exclusively. All observed 4f – 4f transitions of the Sm{sup 3+} centres in the optical absorption and luminescence spectra of the investigated glasses are identified. Most intense emission band of the Sm{sup 3+} ions peaked about 598 nm ({sup 4}G{sub 5/2} → {sup 6}H{sub 7/2} transition) is characterised by a single exponential decay with typical lifetime values, which depend on the basic glass composition as well as concentration and local structure of the Sm{sup 3+} luminescence centres. The quantum efficiency has been evaluated for observed transitions of the Sm{sup 3+} centres using obtained experimental lifetimes and radiative lifetimes calculated by Judd–Ofelt theory. The calculated high quantum efficiencies and measured quantum yields of luminescence show that the investigated borate glasses are perspective luminescence materials. Energy transfer from the Ce{sup 3+} non-controlled impurity and intrinsic luminescence centres to the Sm{sup 3+} centres has been observed. Peculiarities of the Sm{sup 3+} local structure in the network of investigated glasses have been discussed based on the obtained spectroscopic results and structural data. - Highlights: • The Sm-doped Li{sub 2}B{sub 4}O{sub 7}, LiKB{sub 4}O{sub 7}, Ca

  11. Sm Transition Probabilities and Abundances

    CERN Document Server

    Lawler, J E; Sneden, C; Cowan, J J

    2005-01-01

    Radiative lifetimes, accurate to +/- 5%, have been measured for 212 odd-parity levels of Sm II using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier-transform spectrometry to determine transition probabilities for more than 900 lines of Sm II. This work is the largest-scale laboratory study to date of Sm II transition probabilities using modern methods. This improved data set has been used to determine a new solar photospheric Sm abundance, log epsilon = 1.00 +/- 0.03, from 26 lines. The spectra of three very metal-poor, neutron-capture-rich stars also have been analyzed, employing between 55 and 72 Sm II lines per star. The abundance ratios of Sm relative to other rare earth elements in these stars are in agreement, and are consistent with ratios expected from rapid neutron-capture nucleosynthesis (the r-process).

  12. Highly Enhanced Concentration and Stability of Reactive Ce^3+ on Doped CeO_2 Surface Revealed In Operando

    OpenAIRE

    Chueh, William C.; McDaniel, Anthony H.; Grass, Michael E.; Hao, Yong; Jabeen, Naila; Liu, Zhi; Haile, Sossina M.; McCarty, Kevin F.; Bluhm, Hendrik; El Gabaly, Farid

    2012-01-01

    Trivalent cerium ions in CeO_2 are the key active species in a wide range of catalytic and electro-catalytic reactions. We employed ambient pressure X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy to quantify simultaneously the concentration of the reactive Ce^3+ species on the surface and in the bulk of Sm-doped CeO_2(100) in hundreds of millitorr of H2–H2O gas mixtures. Under relatively oxidizing conditions, when the bulk cerium is almost entirely in the 4+ oxida...

  13. SM18 Visits and Access

    CERN Multimedia

    2012-01-01

      VISITS The rules and conditions to be followed for visits in the SM18 Hall are laid out in the EDMS 1205328 document. No visit is allowed without prior reservation.   ACCESS Special access right is needed ONLY from 7 p.m. to 7 a.m. and during week-ends. From 1 December, the current SM18 access database will be closed and a new one “SM18-OWH outside normal hours” started from scratch. Requests, via EDH SM18-OWH, will have to be duly justified.   For further information, please contact Evelyne Delucinge.

  14. On oxygen perovskites of type Ba3Bsup(III)RuIrO9

    International Nuclear Information System (INIS)

    The black perovskites Ba3Bsup(III)RuIrO9 with Bsup(III) = La, Nd, Sm, Gd, Dy, Er, Yb, In, Sc are isotypic. They crystallize in a hexagonal BaTiO3 structure (sequence (hcc)2). The mean oxydation state of the noble metal ions is +4.5. (author)

  15. Synthesis of Sm3+-doped strontium barium niobate crystals in glass by samarium atom heat processing

    International Nuclear Information System (INIS)

    New glasses giving the crystallization of Sm3+-doped Sr x Ba1-x Nb2O6 (SBN) ferroelectrics have been developed in the Sm2O3-SrO-BaO-Nb2O5-B2O3 system, and the formation of SBN crystal dots and lines by continuous wave Nd:YAG laser (wavelength:1064 nm, power: 1 W) irradiations, i.e., samarium atom heat processing, has been examined. The formation of Sm3+-doped SBN non-linear optical crystals is confirmed from X-ray diffraction analyses, micro-Raman scattering spectra, second harmonic generations, and photoluminescence spectra. Sm3+-doped SBN crystal dots with the diameters of 20-70 μm and lines with the widths of 20-40 μm are written at the surface of some glasses such as 10Sm2O3.10SrO.10BaO.20Nb2O5.50B2O3 (mol%) by Nd:YAG laser irradiations with the irradiation times of 20-70 s for the dots and with the scanning speeds of 1-5 μm/s for the lines. The present study suggests that the samarium atom heat processing has a potential for the patterning of optical waveguides consisting of ferroelectric SBN crystals in glass substrates

  16. Preparation and Oxygen Permeability of BaCo0.7Fe0.2Nb0.1O3-δ Membrane Modified by Ce0.8Y0.2O2-δ Porous Layer on the Air Side

    Directory of Open Access Journals (Sweden)

    Yuan Qiang

    2013-01-01

    Full Text Available BaCo0.7Fe0.2Nb0.1O3−δ (BCFN dense ceramic membrane with submicron-Ce0.8Y0.2O2−δ (YDC porous layer was investigated by the partial oxidation of coke oven gas (COG in hydrogen production. XRD analysis showed this composite had good stability and no chemical reaction at high temperature. SEM and TEM characterization further showed BCFN membrane was uniformly modified by YDC porous layer (about 5~6 μm thickness formed by the accumulation of relative nanoparticles. At the respective COG flux and air flux of 108 mL/min and 173 mL/min, the oxygen permeation flux of BCFN modified by submicron-YDC porous layer reached 16.62 mL·min−1·cm−2, which was about 23.5% higher than that of pure BCFN membrane. Therefore, submicron-YDC porous layer obviously improved the oxygen permeation flux of BCFN membrane and its stability at 875°C.

  17. LaCoO3: Promising cathode material for protonic ceramic fuel cells based on a BaCe0.2Zr0.7Y0.1O3−δ electrolyte

    DEFF Research Database (Denmark)

    Ricote, Sandrine; Bonanos, Nikolaos; Lenrick, Filip;

    2012-01-01

    showed the presence of the infiltrated LC in the full cathode depth. Transmission electron micrographs revealed LC grains (60–80 nm) covering partly the BCZY27 grains (200 nm–1 μm). Impedance spectra were recorded at 500 °C and 600 °C, varying the oxygen partial pressure and the water vapour pressure......Symmetric cells (cathode/electrolyte/cathode) were prepared using BaCe0.2Zr0.7Y0.1O3−δ (BCZY27) as proton conducting electrolyte and LaCoO3 (LC) infiltrated into a porous BCZY27 backbone as cathode. Single phased LC was formed after annealing in air at 600 °C for 2 h. Scanning electron micrographs...... independent on the water vapour pressure while the charge transfer ASR values increase with higher pH2O. The cathode ASRs of 0.39 and 0.11 Ω cm2 at 500 and 600 °C respectively, in air (pH2O = 0.01 atm) are the lowest reported to the authors’ knowledge for PCFC cathodes. Furthermore, this work shows that the...

  18. Carbon Deposition and Sulfur Tolerant La0.4Sr0.5Ba0.1TiO3–La0.4Ce0.6O1.8 Anode Catalysts for Solid Oxide Fuel Cells

    International Nuclear Information System (INIS)

    Highlights: • Carbon deposition and sulfur tolerant perovskite LSBT–LDC anode was prepared. • LSBT–LDC showed higher electrochemical performance than LSBT anode in sour CH4. • The addition of LDC contributed to the removal of carbon deposition on anode. - Abstract: In this work, LSBT–LDC (La0.4Sr0.5Ba0.1TiO3–La0.4Ce0.6O1.8) was successfully prepared by impregnating LSBT and LDC solutions on porous YSZ matrix. The prepared anode material exhibited higher catalytic performance and better resistance against carbon deposition than LSBT anode material in 5000 ppm H2S containing methane. Electrochemical impedance spectra (EIS) characterizations revealed that the addition of LDC significantly reduces the activation polarization resistance. Energy-dispersive X-ray spectroscopy (EDX) results indicated that the distribution of impregnated oxides in the matrix was uniform. The results of X-ray photoelectron spectroscopy (XPS) and temperature-programed oxidation (TPO) indicated that LSBT–LDC anode could enhance the tolerance against carbon deposition. The gas chromatography (GC) analysis proved that the modification of LDC could effectively promote the activation of methane and contribute to remove carbon deposition formed on the catalyst simultaneously

  19. Fabrication of large single-domain Sm123 superconductors by OCMG method

    International Nuclear Information System (INIS)

    Melt processing of Sm-Ba-Cu-O bulk superconductors was studied to find the optimum conditions for fabricating a large single-domain superconductor. First, the holding time at the maximum temperature for the partial melting is important for the fabrication of a uniform bulk, especially for a large diameter. When the holding time at the maximum temperature during partial melting was not enough, two separated regions were observed, which can be diminished by sufficient holding time. Next we studied the optimum conditions for grain growth, varying the temperature gr[ient and cooling rate. The processing condition with which we have succeeded in growing a single-domain SmBa2Cu3Oy (Sm123 hereafter) with dimensions of 35 φ x 15 mm2 is a temperature gr[ient of 7.5 C cm-1 with a slow cooling rate of 0.33 C h-1. (orig.)

  20. Synthesis and characterization of BaAl2O4:Eu2+ co-doped with different rare earth ions

    International Nuclear Information System (INIS)

    Combustion method was used in this study to prepare BaAl2O4:Eu2+ phosphors co-doped with different trivalent rare-earths (Re3+=Dy3+, Nd3+, Gd3+, Sm3+, Ce3+, Er3+, Pr3+ and Tb3+) ions at an initiating temperature of 600 °C. The phosphors were annealed at 1000 °C for 3 h. As confirmed from the X-ray diffraction (XRD) data, both as prepared and post annealed samples crystallized in the well known hexagonal structure of BaAl2O4. All samples exhibited bluish-green emission associated with the 4f65d1→4f7 transitions of Eu2+ at ∼500 nm. Although the highest intensity was observed from Er3+ co-doping, the longest afterglow (due to trapping and detrapping of charge carriers) was observed from Nd3+ followed by Dy3+ co-doping. The traps responsible for the long afterglow were studied using thermoluminescence (TL) spectroscopy.

  1. Investigation into kinetics of redox interaction in the system Ce(4) β-diketonate-additional ligand

    International Nuclear Information System (INIS)

    The rate of reduction of β-diketonate complexes of Ce(4) to Ce(3) β-diketonates in benzene solution in the presence and in the absence of additional ligands is studied using spectrophotometry. The rate of reduction of Ce(4) β-diketonates increases in the series Ce(TTFA)44444 (TTFA - thenoyltrifluoroacetone, DPM- --dipivaloylmethane, DBM - dibenzoylemethane, BA benzoylacetone, AA - acetylaceton). The studied phosphorus-containing additional ligands as to their effect on the rate of Ce (4) reduction can be arranged in the following order: trioctylphosphine oxide>triphenylphosphine oxide>tributyl phosphate

  2. Why the Four SM Families

    CERN Document Server

    Sultansoy, S F

    2001-01-01

    The flavor democracy favors the existence of the nearly degenerate fourth SM family, whereas the fifth SM family is disfavored both by the mass phenomenology and precision tests of the Standard Model. The multi-hundreds GeV fourth family quarks will be copiously produced at the LHC. However, the first indication of the fourth family may come from the Higgs search at the upgraded Tevatron.

  3. Effect of Sintering Temperature on Microstructure, Chemical Stability and Electrical Properties of Transition Metal or Yb-Doped BaZr0.1Ce0.7Y0.1M0.1O3-δ (M = Fe, Ni, Co and Yb

    Directory of Open Access Journals (Sweden)

    Behzad eMirfakhraei

    2014-03-01

    Full Text Available Perovskite-type BaZr0.1Ce0.7Y0.1M0.1O3-δ (M = Fe, Ni, Co and Yb (BZCY-M oxides were synthesized using the conventional solid-state reaction method at 1350-1550 oC in air in order to investigate the effect of dopants on sintering, crystal structure, chemical stability under CO2 and H2S, and electrical transport properties. The formation of the single-phase perovskite-type structure with an orthorhombic space group Imam was confirmed by Rietveld refinement using powder X-ray diffraction (PXRD for the Fe, Co, Ni and Yb-doped samples. The BZCY-Co and BZCY-Ni oxides show a total electrical conductivity of 0.01 and 8 × 10-3 Scm-1 at 600 oC in wet H2 with an activation energy of 0.36 and 0.41 eV, respectively. Scanning electron microscopy (SEM and energy-dispersive X-ray analysis (EDX revealed Ba and Co rich secondary phase at the grain-boundaries, which may explain the enhancement in the total conductivity of the BZCY-Co. However, ex-solution of Ni at higher sintering temperatures, especially at 1550 oC, decreases the total conductivity of the BZCY-Ni material. The Co and Ni dopants act as a sintering aid and form dense pellets at a lower sintering temperature of 1250 oC. The Fe, Co and Ni-doped BZCY-M samples synthesized at 1350 oC show stability in 30 ppm H2S/H2 at 800 oC, and increasing the firing temperature to 1550 oC, enhanced the chemical stability in CO2 / N2 (1: 2 at 25-900 oC. The BZCY-Co and Ni compounds with high conductivity in wet H2 could be considered as possible anodes for intermediate temperature solid oxide fuel cells (IT-SOFCs.

  4. Influence of the indium concentration on microstructural and electrical properties of proton conducting NiO–BaCe{sub 0.9−x}In{sub x}Y{sub 0.1}O{sub 3−δ} cermet anodes for IT-SOFC application

    Energy Technology Data Exchange (ETDEWEB)

    Zunic, Milan, E-mail: milan@iq.unesp.br [Instituto de Quimica, UNESP–LIEC, CMDMC, Rua Prof. Francisco Degni, 55, CEP 14800-900, Araraquara, SP (Brazil); Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11000 Belgrade (Serbia); Brankovic, Goran [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11000 Belgrade (Serbia); Foschini, Cesar Renato; Cilense, Mario; Longo, Elson; Varela, José Arana [Instituto de Quimica, UNESP–LIEC, CMDMC, Rua Prof. Francisco Degni, 55, CEP 14800-900, Araraquara, SP (Brazil)

    2013-06-25

    Highlights: ► The influence of indium concentration on anode properties was investigated. ► The cermet anode powders were obtained without any undesirable phases. ► Anode substrates were tested on chemical stability in the CO{sub 2} atmosphere. ► Conductivity measurements confirmed percolation through Ni grains. ► Fuel cell tests confirmed functionality of anode substrates. -- Abstract: Optimization of the major properties of anodes based on proton conductors, such as microstructure, conductivity and chemical stability, is yet to be achieved. In this study we investigated the influence of indium on the chemical stability, microstructural and electrical characteristics of proton conducting NiO–BaCe{sub 0.9−x}In{sub x}Y{sub 0.1}O{sub 3−δ} (NiO–BCIYx) anodes. Four compositions of cermet anode substrates NiO–BCIYx were prepared using the method of evaporation and decomposition of solutions and suspensions (EDSS). Sintered anode substrates were reduced and their microstructural and electrical properties were examined before and after reduction as a function of the amount of indium. Anode substrates tested on chemical stability in the CO{sub 2} atmosphere showed high stability compared to anode substrates based on commonly used doped barium cerates. Microstructural properties of the anode pellets before and after testing in CO{sub 2} were investigated using X-ray diffraction analysis. Impedance spectroscopy measurements were used for evaluation of electrical properties of the anode pellets and the conductivity values of reduced anodes of more than 14 S cm{sup −1} at 600 °C confirmed percolations through Ni particles. Under fuel cell operating conditions, the cell with a Ni–BCIY20 anode achieved the highest performance, demonstrating a peak power density 223 mW/cm{sup 2} at 700 °C confirming the functionality of Ni–BCIY anodes.

  5. Stability, characterization and functionality of proton conducting NiO–BaCe{sub 0.85−x}Nb{sub x}Y{sub 0.15}O{sub 3−δ} cermet anodes for IT-SOFC application

    Energy Technology Data Exchange (ETDEWEB)

    Žunić, Milan, E-mail: milan@iq.unesp.br [Instituto de Quimica, UNESP-LIEC, CMDMC, Rua Prof. Francisco Degni, 55, CEP 14800-900, Araraquara, SP (Brazil); Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11000 Belgrade (Serbia); Branković, Goran [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11000 Belgrade (Serbia); Basoli, Francesco [Department of Chemical Science and Technologies, University of Rome Tor Vergata, Via Ricerca Scientifica 1, 00133 Rome (Italy); Cilense, Mario; Longo, Elson; Varela, José Arana [Instituto de Quimica, UNESP-LIEC, CMDMC, Rua Prof. Francisco Degni, 55, CEP 14800-900, Araraquara, SP (Brazil)

    2014-10-01

    Highlights: • The influence niobium concentration on properties of anode substrates was investigated. • The cermet anode powders were obtained without any undesirable phases. • Porous anode substrates showed chemical stability in the CO{sub 2} atmosphere. • Conductivity values of reduced anode samples were σ{sup *} > 50 S cm{sup −1}. • Fuel cell tests demonstrated functionality of anode substrates. - Abstract: There are many of properties of anodes based on proton conductors, like microstructure, conductivity and chemical stability, which should be optimized. In this work we were dealing with the influence of niobium on the chemical stability, microstructural and electrical characteristics of proton conducting NiO–BaCe{sub 0.85−x}Nb{sub x}Y{sub 0.15}O{sub 3−δ} (NiO–BCNYx) anodes. Four anode substrates NiO–BCNYx of different Nb concentration were prepared using the method of evaporation and decomposition of solutions and suspensions (EDSS). Sintered anode substrates were reduced and their microstructural and electrical properties were examined before and after reduction as a function of the amount of niobium. Chemical stability tests showed strong influence of Nb amount on the chemical stability of anodes in the CO{sub 2}. Microstructural properties of the anode pellets before and after testing in CO{sub 2} were investigated using X-ray diffraction analysis. Electrical properties of anode samples were examined by impedance spectroscopy measurements and the conductivity values of reduced anodes were more than 50 S cm{sup −1} at 600 °C confirming percolation through Ni particles. Fuel cells were fabricated with aim to examine the functionality of anodes. During the fuel cell test the cell with Ni–BCNY10 anode achieved the highest performance, demonstrating a peak power density of 164 mW cm{sup −2} at 650 °C, which confirmed the functionality of Ni–BCNY anodes.

  6. A cobalt-free SrFe{sub 0.9}Sb{sub 0.1}O{sub 3-{delta}} cathode material for proton-conducting solid oxide fuel cells with stable BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.1}Yb{sub 0.1}O{sub 3-{delta}} electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Yihan; Zhao, Ling; Lin, Bin; Liu, Xingqin [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China); Zhang, Xiaozhen [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China); Key Laboratory of Jiangxi Universities for Inorganic Membranes, School of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333001 (China); Wang, Songlin [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China); Department of Mechanical Engineering, Tongling University (TLU), Tongling, Anhui 244000 (China)

    2010-10-15

    A cobalt-free cubic perovskite oxide SrFe{sub 0.9}Sb{sub 0.1}O{sub 3-{delta}} (SFSb) is investigated as a novel cathode for proton-conducting solid oxide fuel cells (H-SOFCs). XRD results show that SFSb cathode is chemically compatible with the electrolyte BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.1}Yb{sub 0.1}O{sub 3-{delta}} (BZCYYb) for temperatures up to 1000 C. Thin proton-conducting BZCYYb electrolyte and NiO-BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.1}Yb{sub 0.1}O{sub 3-{delta}} (NiO-BZCYYb) anode functional layer are prepared over porous anode substrates composed of NiO-BZCYYb by a one-step dry-pressing/co-firing process. Laboratory-sized quad-layer cells of NiO-BZCYYb/NiO-BZCYYb/BZCYYb/SFSb are operated from 550 to 700 C with humidified hydrogen ({proportional_to}3% H{sub 2}O) as fuel and the static air as oxidant. An open-circuit potential of 0.996 V, maximum power density of 428 mW cm{sup -2}, and a low electrode polarization resistance of 0.154 {omega} cm{sup 2} are achieved at 700 C. The experimental results indicate that the cobalt-free SFSb is a promising candidate for cathode material for H-SOFCs. (author)

  7. Phase equilibria in Sm-Ga-S ternary system according to SmGa2-GaS, SmGa2-SmS, Sm3S4-Ga2S3, SmS-GaS, Sm-GaS cross sections

    International Nuclear Information System (INIS)

    Phase equilibria in ternary system Sm-Ga-S over cross sections SmGa2-GaS, SmGa2-SmS, SmS-GaS, Sm3S4-Ga2S3, Sm-GaS have been studied for the first time using the methods of physicochemical analysis, their T-x projections were plotted. The cross sections SmGa2-GaS, SmGa2-SmS, Sm3S4-Ga2S3 and SmS-GaS are quasibinary, while Sm-GaS is nonquasibinary one. Formation of two ternary compounds of the composition Sm4GaS5 and Sm5Ga2S5 was ascertained by peritectic reactions

  8. Improving CE with PDM

    NARCIS (Netherlands)

    Wognum, P.M. (Nel); Bondarouk, T.V. (Tanya); Weber, F.; Pawar, K.S.; Thoben, K.D.

    2003-01-01

    The concept of Concurrent Engineering (CE) centers around the management of information so that the right information will be at the right place at the right time and in the right format. Product Data Management (PDM) aims to support a CE way of working in product development processes. In specific

  9. Structure and magnetic properties of the REAuBi2 (RE=La–Nd, Sm) phases

    International Nuclear Information System (INIS)

    We present the crystal structures and basic magnetic properties of the REAuBi2 (RE=La–Nd, Sm) compounds. This isostructural family crystallizes in the tetragonal P4/nmm (no. 129) HfCuSi2-type, as determined by single crystal X-ray diffraction. Three distinct substructures are present: an RE layer, a tetrahedral AuBi layer, and a Bi square net layer. Electronic structure calculations indicate that these compounds display bands which cross the Fermi level, derived from both the Bi square net and the covalent AuBi layer. The small size of LaAuBi2 crystals precluded detailed physical property measurements, whereas large single crystals could be grown for all other phases investigated here. Single crystal measurements of CeAuBi2, PrAuBi2, and NdAuBi2 show overall antiferromagnetic ordering and decreasing magnetic anisotropy with decreasing rare earth size. SmAuBi2 also shows signatures of magnetic ordering. - Graphical abstract: The crystal structures and basic electronic and magnetic properties of the five REAuBi2 (RE=La–Nd, Sm) phases are presented. These tetragonal structures have alternating layers of AuBi4 tetrahedra and a Bi square net balanced by RE cations. Measurements performed on single crystals show strong magnetic anisotropy for CeAuBi2 and PrAuBi2 and weak anisotropy for NdAuBi2. SmAuBi2 is weakly magnetic. - Highlights: • We present the structures and basic properties of single crystals of the new, tetragonal REAuBi2 (RE=La–Nd, Sm) phases. • CeAuBi2, PrAuBi2, NdAuBi2, and SmAuBi2 order magnetically. • CeAuBi2 and PrAuBi2 display magnetic anisotropy. • CeAuBi2 appears analogous to CeAuSb2 and may be worthy of further study as a potential system for quantum criticality

  10. Verwey Transition under Oxygen Loading in RBaFe 2O 5+ w ( R=Nd and Sm)

    Science.gov (United States)

    Karen, P.; Woodward, P. M.; Santhosh, P. N.; Vogt, T.; Stephens, P. W.; Pagola, S.

    2002-09-01

    Double-cell perovskites RBaFe 2O 5+ w ( R= Nd and Sm) are synthesized in the -0.03Sm atom than for R=Nd. The discontinuity of the SmBaFe 2O 5+ w transition also persists into much higher levels of the oxygen nonstoichiometry w than for the R=Nd variant. Whereas 3D-charge-ordered SmBaFe 2O 5.00 is isostructural with TbBaFe 2O 5.00 adopting space group Pmma, NdBaFe 2O 5.00 undergoes a more profound structural change upon entering the charge-ordered state, the structure of which is refined in the P2 1ma symmetry from high-resolution X-ray synchrotron diffraction data.

  11. Synthesis and characterization of BaAl{sub 2}O{sub 4}:Eu{sup 2+} co-doped with different rare earth ions

    Energy Technology Data Exchange (ETDEWEB)

    Lephoto, M.A. [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Ntwaeaborwa, O.M., E-mail: ntwaeab@ufs.ac.za [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Pitale, Shreyas S.; Swart, H.C. [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth, ZA 6031 (South Africa); Mothudi, B.M. [Department of Physics, University of South Africa, P.O Box 392, Pretoria, ZA 6031 (South Africa)

    2012-05-15

    Combustion method was used in this study to prepare BaAl{sub 2}O{sub 4}:Eu{sup 2+} phosphors co-doped with different trivalent rare-earths (Re{sup 3+}=Dy{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Sm{sup 3+}, Ce{sup 3+}, Er{sup 3+}, Pr{sup 3+} and Tb{sup 3+}) ions at an initiating temperature of 600 Degree-Sign C. The phosphors were annealed at 1000 Degree-Sign C for 3 h. As confirmed from the X-ray diffraction (XRD) data, both as prepared and post annealed samples crystallized in the well known hexagonal structure of BaAl{sub 2}O{sub 4}. All samples exhibited bluish-green emission associated with the 4f{sup 6}5d{sup 1}{yields}4f{sup 7} transitions of Eu{sup 2+} at {approx}500 nm. Although the highest intensity was observed from Er{sup 3+} co-doping, the longest afterglow (due to trapping and detrapping of charge carriers) was observed from Nd{sup 3+} followed by Dy{sup 3+} co-doping. The traps responsible for the long afterglow were studied using thermoluminescence (TL) spectroscopy.

  12. Dielectric function of SmS

    International Nuclear Information System (INIS)

    The zone-center longitudinal optical phonon of semiconducting SmS shows a 10% softening with respect to that of EuS. This result confirms the lattice-dynamical model prediction and provides first experimental evidence for the existence of an anomalous dipolar charge deformability of the Sm2+ ion in SmS. (author)

  13. An X-ray diffraction and P-31 MAS NMR study of rare-earth phosphate glasses, (R2O3)(x)(P2O5)(1-x), x=0.175-0.263, R = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er

    OpenAIRE

    Cole, Jacqueline M.; van Eck, Ernst R. H.; Mountjoy, Gavin; Anderson, Ruth; Brennan, Tessa; Bushnell-Wye, Graham; Newport, Robert J; Saunders, George A.

    2001-01-01

    An X-ray diffraction and P-31 MAS NMR study of rare-earth phosphate glasses of composition, (R2O3)(x)P2O5)(1-x), where x = 0.175-0.263 and R = La-Er (except for Pm), is presented. The structures of these materials were investigated as a function of (a) rare-earth atomic number and (b) glass composition, The results show an increase in rare-earth coordination number from six to seven as the rare-earth ion increases in size. This effect is most evident for the rare earths, Ce, Pr and Nd, and ap...

  14. Excited states in 146Sm and 147Sm

    International Nuclear Information System (INIS)

    The sup(144,146)Nd(α,xn) and sup(146,148)Nd(3He,xn) reactions with Esub(α) = 20 - 43 MeV and E3sub(He) = 19 - 27 MeV are used to investigate excited states in the isotopes 146Sm and 147Sm. The experiments involve measurements of singles γ-ray spectra and conversion electron spectra, γ-ray angular distributions and three parameter (E sub(γ)E sub(γ) time) coincidences. From these experiments information is obtained for states with spin up to I = 13+ and I = 27/2-, respectively, These states are interpeted within the framework of the cluster-vibration model (CVM) as well as the shell model. (author)

  15. Octupole correlations in 143 Ba and 147 Pr

    International Nuclear Information System (INIS)

    High spin states in neutron-rich odd-Z 143,145 Ba nuclei have been investigated from the study of prompt γ-rays in the spontaneous fission of 252 Cf. Alternating parity bands are identified for the first time in 145 Ba and extended in 143 Ba. A new side band with equal, constant dynamic and kinematic moments of inertia equal to the rigid body value, as found in superdeformed bands, is discovered in 145 Ba. Enhanced E1 transitions between the negative- and positive-parity bands in these nuclei give evidence for strong octupole deformation in 143 Ba and in 145 Ba. These collective bands show competition and co-existence between symmetric and asymmetric shapes in 145 Ba. The first evidence is found for crossing M1 and E1 transitions between the s = +i and s = -i doublets in 143 Ba. Neutron-rich 147 Pr also was studied in the spontaneous fission of 252 Cf. Possible parity doublets observed in 147 Pr with N = 88 indicate that neutron-rich 59147 Pr88 nucleus exhibits strong octupole correlations like those observed in the 58146 Ce88 core. (authors)

  16. Probing the Metal-Insulator Transition in BaTiO3 by Electrostatic Doping

    Science.gov (United States)

    Raghavan, Santosh; Zhang, Jack Y.; Shoron, Omor F.; Stemmer, Susanne

    2016-07-01

    The metal-to-insulator transition in BaTiO3 is investigated using electrostatic doping, which avoids effects from disorder and strain that would accompany chemical doping. SmTiO3/BaTiO3/SrTiO3 heterostructures are doped with a constant sheet carrier density of 3 ×1014 cm-2 that is introduced via the polar SmTiO3/BaTiO3 interface. Below a critical BaTiO3 thickness, the structures exhibit metallic behavior with high carrier mobilities at low temperatures, similar to SmTiO3/SrTiO3 interfaces. Above this thickness, data indicate that the BaTiO3 layer becomes ferroelectric. The BaTiO3 lattice parameters increase to a value consistent with a strained, tetragonal unit cell, the structures are insulating below ˜125 K , and the mobility drops by more than an order of magnitude, indicating self-trapping of carriers. The results shed light on the interplay between charge carriers and ferroelectricity.

  17. NanoSIMS studies of Ba isotopic compositions in single presolar silicon carbide grains from AGB stars and supernovae

    Science.gov (United States)

    Marhas, K. K.; Hoppe, P.; Ott, U.

    2007-08-01

    We have studied 74 single presolar silicon carbide grains with sizes between 0.2 and 2.6 μm from the Murchison and Murray meteorites for Ba isotopic compositions using NanoSIMS. We also analyzed 7 SiC particles either consisting of sub-micron-size SiC grains or representing a morphologically and isotopically distinct subgroup. Of the 55 (likely) mainstream grains, originating from asymptotic giant branch (AGB) stars, 32 had high enough Ba contents for isotopic analysis. For 26 of them, CsHx interferences were either negligible or could be corrected with confidence. They exhibit typical s-process Ba isotopic patterns with slightly higher than solar 134Ba/136Ba and lower than solar 135,137,138Ba/136Ba ratios. Results are generally well explained in the context of neutron capture nucleosynthesis in low mass (1-3 M⊙) AGB stars and provide constraints on AGB models, by reducing the needed 13C spread from factor of ˜20 down to 2. Out of the 19 supernova X grains, three had sufficient concentrations for isotopic analysis. They tend to exhibit higher than solar 134Ba/136Ba and 138Ba/136Ba ratios, close to solar 137Ba/136Ba, and 135Ba/136Ba lower than solar but higher than in mainstream grains. This signature could indicate a mixture of n-burst type Ba with either "normal Ba" more s-process-rich than solar, or normal Ba plus weak s-process Ba. In the n-burst component Cs may have to be separated from Ba at ˜10 years after the SN explosion. Depending on predictions for its composition, another possibility is early separation (at ˜1 year) coupled with addition of some unfractionated n-burst matter. Abundances of trace elements (Sr, Zr, Cs, La, and Ce) analyzed along with Ba signify that implantation may have been an important process for their introduction.

  18. Influence of preparation conditions on 211 particle refinement in YBCO bulk superconductors with Ce addition

    Energy Technology Data Exchange (ETDEWEB)

    Diko, Pavel, E-mail: dikos@saske.sk; Volochová, Daniela; Radušovská, Monika; Zmorayová, Katarína; Šefčiková, Martina; Antal, Vitalij; Jurek, Karel; Jirsa, Miloš; Kováč, Jozef

    2013-11-15

    Highlights: •CeO{sub 2} causes coarsening of Y211 particles in nominal composition Y{sub 1.5}Ba{sub 2}Cu{sub 3}O{sub x}. •Y211 particles grow during sintering at 940 °C. •High local density of Y211 particles hinders their growth at sintering stage. •Addition of BaCeO{sub 3} leads to smaller Y211 particles. •Skeleton of Y211 particles prevents pollution of grown samples. -- Abstract: The influence of CeO{sub 2} and BaCeO{sub 3} addition and the influence of processing conditions on Y{sub 2}BaCuO{sub 5} (Y211) particle size and particle distribution in melt-processed YBa{sub 2}Cu{sub 3}O{sub 7}/Y{sub 2}BaCuO{sub 5} (Y123/Y211) bulk superconductors with nominal composition Y{sub 1.5}Ba{sub 2}Cu{sub 3}O{sub x} was investigated. Ce dissolved in the peritectic melt can actively hinder the Y211 particle growth by the Ostwald ripening process at melting stage. At sintering of intensively milled samples, Y211 particles in the charge free of CeO{sub 2} are smaller than Y211 particles formed in the charge with CeO{sub 2} addition and this behaviour can be related to the melt formation around added CeO{sub 2}. The Y211 particle refinement in the mildly milled samples with large Y123 particles in the pressed green bodies is caused by very dense Y211 skeleton resistant to melt formation at the sintering stage. This skeleton is a barrier for pollution of the sample from the substrate and from the seed. BaCeO{sub 3} added instead CeO{sub 2} causes significant Y211 particle refinement also in the samples with homogenously distributed Y211 particles.

  19. La3+ and Ce4+ doping of hard-magnetic ferrites

    International Nuclear Information System (INIS)

    Regularities in the formed structure and properties of M1-xRx·nFe2O3 (n=4-6), M=Ba, Sr, Pb; R=La, Ce substituted ferrites during the substitution of M2+ by La3+ or Ce4+ ions in the x=0-0.1 range were studied by physicochemical methods. Dependencies of changing density and porosity in sintered ferrites, magnetic and strength characteristics of gained anisotropic ferrites with x=0.6 and 0.1 are given. The best magnetic strength properties were obtained for the Ce4+ doped barium ferrite BaO·5.5Fe2O3 at x=0.1. X-ray diffraction of barium ferrites La3+ doped (x>0.05) demonstrates presence of ferrimagnetic phase (CaLa)0.5Fe12O19 besides the basic BaFe12O19 phase

  20. Preparation, crystal structure and properties of HoBaCo{sub 2−x}Fe{sub x}O{sub 5+δ}

    Energy Technology Data Exchange (ETDEWEB)

    Gavrilova, L. Ya.; Volkova, N.E.; Aksenova, T.V. [Ural Federal University, Yekaterinburg (Russian Federation); Cherepanov, V.A., E-mail: Vladimir.cherepanov@usu.ru [Ural Federal University, Yekaterinburg (Russian Federation)

    2013-06-01

    Highlights: ► Synthesis of HoBaCo{sub 2−x}Fe{sub x}O{sub 5+δ} by glycerin nitrate technique in air and in pure oxygen. ► Substitution of Co by Fe influences both the value of oxygen content and crystal structure. ► The changes of oxygen content were measured by TGA. - Abstract: A series of samples of overall composition HoBaCo{sub 2−x}Fe{sub x}O{sub 5+δ} with 0.0 ≤ x ≤ 0.8 were prepared by glycerin nitrate technique in air and in pure oxygen. Irrespective of atmosphere used the homogeneity range of single phase iron substituted holmium barium cobaltate was proved to exist within the range 0.0 ≤ x ≤ 0.4. All samples prepared in air and samples within the compositional range 0.2 ≤ x ≤ 0.4 obtained in oxygen possess tetragonal a{sub p} × a{sub p} × 2a{sub p} (sp. gr. P4/mmm) structure. HoBaCo{sub 2}O{sub 5+δ} and HoBaCo{sub 1.9}Fe{sub 0.1}O{sub 5+δ} synthesized in oxygen crystallized in orthorhombic a{sub p} × 2a{sub p} × 2a{sub p} (sp. gr. Pmmm) structure. The structural parameters were refined by the Rietveld analysis. It was shown that parameter a remains practically constant while parameter c gradually increases with the increase of iron content. The changes of oxygen content in HoBaCo{sub 2−x}Fe{sub x}O{sub 5+δ} (x = 0, 0.2, 0.4) were measured by TGA within the temperature range 25–1100 °C in air. The absolute value of oxygen content was determined by the reduction of the samples in hydrogen flow. The influence of oxygen and iron content on the crystal structure has been discussed. The chemical stability of HoBaCo{sub 2−x}Fe{sub x}O{sub 5+δ} in contact with the solid electrolyte materials Ce{sub 0.8}Sm{sub 0.2}O{sub 2} and Zr{sub 0.85}Y{sub 0.15}O{sub 2} was examined.

  1. Thickness dependence of Ic and Jc of LTG-SmBCO coated-conductor on IBAD-MgO tapes

    International Nuclear Information System (INIS)

    We have reported SmBa2Cu3Oy (SmBCO) films on single crystalline substrates prepared by low-temperature growth (LTG) technique. The LTG-SmBCO films showed high critical current densities in magnetic fields compared with conventional SmBCO films prepared by pulsed laser deposition (PLD) method. In this study, to enhance critical current (Ic) in magnetic field, we fabricated thick LTG-SmBCO films on metal substrates with ion-beam assisted deposition (IBAD)-MgO buffer and estimated the Ic and Jc in magnetic fields. All the SmBCO films showed c-axis orientation and cube-on-cube in-plane texture. Tc of the LTG-SmBCO films were 93.1-93.4 K. Jc and Ic of a 0.5 μm-thick SmBCO film were 3.0 MA/cm2 and 150 A/cm-width at 77 K in self-field, respectively. Those of a 2.0 μm-thick film were 1.6 MA/cm2 and 284 A/cm-width respectively. Although Ic increased with the film thickness increasing up to 2 μm, the Ic tended to be saturated in 300 A/cm-width. From a cross sectional TEM image of the SmBCO film, we recognized a-axis oriented grains and 45o grains and Cu-O precipitates. Because these undesired grains form dead layers, Ic saturated above a certain thickness. We achieved that Ic in magnetic fields of the LTG-SmBCO films with a thickness of 2.0 μm were 88 A/cm-width at 1 T and 28 A/cm-width at 3 T.

  2. γ -soft Ba146 and the role of nonaxial shapes at N90

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, A. J.; Lister, C. J.; McCutchan, E. A.; Albers, M.; Ayangeakaa, A. D.; Bertone, P. F.; Carpenter, M. P.; Chiara, C. J.; Chowdhury, P.; Clark, J. A.; Copp, P.; David, H. M.; Deo, A. Y.; DiGiovine, B.; D' Olympia, N.; Dungan, R.; Harding, R. D.; Harker, J.; Hota, S. S.; Janssens, R. V. F.; Kondev, F. G.; Liu, S. H.; Ramayya, A. V.; Rissanen, J.; Savard, G.; Seweryniak, D.; Shearman, R.; Sonzogni, A. A.; Tabor, S. L.; Walters, W. B.; Wang, E.; Zhu, S.

    2016-01-01

    Low-spin states in the neutron-rich, N=90 nuclide Ba146 were populated following β decay of Cs146, with the goal of clarifying the development of deformation in barium isotopes through delineation of their nonyrast structures. Fission fragments of Cs146 were extracted from a 1.7-Ci Cf252 source and mass selected using the CAlifornium Rare Ion Breeder Upgrade (CARIBU) facility. Low-energy ions were deposited at the center of a box of thin β detectors, surrounded by a highly efficient high-purity Ge array. The new Ba146 decay scheme now contains 31 excited levels extending up to ~2.5 MeV excitation energy, double what was previously known. These data are compared to predictions from the interacting boson approximation (IBA) model. It appears that the abrupt shape change found at N=90 in Sm and Gd is much more gradual in Ba and Ce, due to an enhanced role of the γ degree of freedom.

  3. Sierra/SM theory manual.

    Energy Technology Data Exchange (ETDEWEB)

    Crane, Nathan Karl

    2013-07-01

    Presented in this document are the theoretical aspects of capabilities contained in the Sierra/SM code. This manuscript serves as an ideal starting point for understanding the theoretical foundations of the code. For a comprehensive study of these capabilities, the reader is encouraged to explore the many references to scientific articles and textbooks contained in this manual. It is important to point out that some capabilities are still in development and may not be presented in this document. Further updates to this manuscript will be made as these capabilites come closer to production level.

  4. Urheilutapahtuman ilmesuunnittelu : Judo SM2011

    OpenAIRE

    Leppänen, Nette

    2013-01-01

    Opinnäytetyössä käsitellään visuaalisen ilmeen suunnittelua urheilutapahtumalle. Opinnäytetyön tavoitteena oli suunnitella Judon SM2011-kisoille tapahtumailme, jolla tavoitetaan potentiaalinen kisayleisö sekä sponsorit, ja jonka avulla kasvatetaan myös lajin tunnettavuutta yleisellä tasolla. Koska kisoilla ei tähän mennessä ole ollut varsinaista kisatunnusta tai muuta graafista ilmettä, suunnittelu lähtee puhtaalta pöydältä, ottaen kuitenkin huomioon asiakkaan asettamat reunaehdot sekä judon ...

  5. Synthesis and characterization of rare earth and transition metal doped BaMgF{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Janssens, S. [Industrial Research Limited, PO Box 31310, Lower Hutt 5040 (New Zealand); MacDiarmid Institute, SCPS, Victoria University of Wellington, PO Box 600, Wellington 6012 (New Zealand); Williams, G.V.M., E-mail: grant.williams@vuw.ac.nz [MacDiarmid Institute, SCPS, Victoria University of Wellington, PO Box 600, Wellington 6012 (New Zealand); Clarke, D. [Industrial Research Limited, PO Box 31310, Lower Hutt 5040 (New Zealand)

    2013-02-15

    BaMgF{sub 4} nanoparticles doped with Ce{sup 3+}, Eu{sup 3+}, Mn{sup 2+}, and Nd{sup 3+} have been successfully synthesized using a reverse microemulsion method. They form nanorods that aggregate into 'moustache' shaped clusters. All doped samples show photoluminescence where the Ce{sup 3+} and Eu{sup 3+} photoluminescence spectra are consistent with substitution onto different crystal sites, while only a single site was found for the Mn{sup 2+} doped sample. Mn{sup 2+} was successfully sensitized by Ce{sup 3+} in BaMgF{sub 4}:Mn{sup 2+}:Ce{sup 3+} nanoparticles. The Ce{sup 3+} PL lifetimes are strongly wavelength dependent, which could be due to different Ce{sup 3+} sites with different PL lifetimes as well as energy transfer between Ce{sup 3+} sites. Transparent thick polymer films containing nanoparticles have been made. The appearance of photoluminescence in rare earth and transition metal doped BaMgF{sub 4} nanoparticles and the ability to make transparent thick films means that the BaMgF{sub 4} nanoparticles have a range of potential applications that include optical amplification. - Highlights: Black-Right-Pointing-Pointer BaMgF{sub 4} nanorods synthesized using a reverse microemulsion method. Black-Right-Pointing-Pointer BaMgF{sub 4} nanorods successfully doped with luminescent ions. Black-Right-Pointing-Pointer Ce{sup 3+} and Eu{sup 3+} ions occupy two distinct crystal sites. Black-Right-Pointing-Pointer Efficient energy transfer from Ce{sup 3+} to Mn{sup 2+} is observed. Black-Right-Pointing-Pointer Transparent nanoparticle/PMMA polymer films were made.

  6. The influence of impurity on the critical thickness of the CeO2 buffer layer for coated conductors

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The lattice parameters, band structure, density of state and elastic constant of RE-doped CeO2 (RE=Sm, Gd, Dy), the buffer material for coated HTS conductors, are calculated using the plane-wave method with pseudopotentials based on the density functional theory (DFT) of first-principle. The rule and mechanism of the effect of rare earth impurity on the critical thickness of the CeO2 buffer layer are investigated. It is found that, in the range of the calculation, the changes of the lattice volume V and elastic constant E of CeO2 with the impurity are mainly determined by the increased electrons ne of the system. The relationship of the elastic constant E and increased electrons ne is established. It is indicated that the critical thickness of the CeO2 single buffer layer doped with Sm, Gd, and Dy may be enhanced by 22%, 43% and 33%, respectively.

  7. Elastic recovery of ReBaCuO bulk superconductors during indentation process at cryogenic temperatures

    International Nuclear Information System (INIS)

    In order to investigate the mechanical properties of RE-Ba-Cu-O bulk superconductors, Indentation Fracture (IF) method using Vickers hardness number has been used to evaluate the fracture toughness at 40-293 K. However, there are some differences between IF values and fracture toughness obtained from other mechanical test. This paper considers the influence of the elastic properties of Y-Ba-Cu-O, Gd-Ba-Cu-O and two types of Sm-Ba-Cu-O on IF values by measuring the indentation depth. As a result, the elastic recovery rate R of Y-Ba-Cu-O increased from 27% to 68% with decreasing temperature. R of Gd-Ba-Cu-O and Sm-Ba-Cu-O also increased from 10-20% to 40-50% with decreasing temperature. In this study, we calculated Vickers hardness numbers using the indentation depths at 40-293 K, and evaluated IF values of bulk superconductors at 40-293 K

  8. Dielectric function of SmS

    International Nuclear Information System (INIS)

    The dielectric response function of SmS and SmAs has been determined via a Kramers-Kronig transformation of the room temperature reflectivity in the range from 10-2 eV to 22 eV. In SmS the assignment of optical transitions, including those from the (S) 3s core level, has been corroborated by the corresponding ones of SmAs. Reductions of the 4f binding energy are revealed in optical f→d transitions as compared to x-ray photoemission data. (author)

  9. Magnetic and structural properties of the 'brown phase' solid solution Ba(Nd2-xLax)CuO5

    International Nuclear Information System (INIS)

    The compounds BaR2CuO5 (R=Y and lanthanides) are well-known impurities that often coexist with the high Tc superconductors, Ba2RCu3O6+x. With R=La and Nd, brown color solid solutions (Ba1+xR2-xCuO5-x) form instead of the 'green phase', BaR2CuO5 (lanthanides with ionic radii smaller than that of Sm). A complete solid solution of Ba(Nd2-xLax)CuO5 exists with the tetragonal space group P4/mbm. Crystallographic studies of selected members (x=0.2, 0.6, 1.2, and 1.6) by X-ray Rietveld refinement technique showed the structure consists of RO8 and BaO10 cages, and square planar CuO4 units. As x increases in Ba(Nd2-xLax)CuO5, the size of these RO8 and BaO10 cages increases. BaLa2CuO5 was confirmed to be ferromagnetic at ∼5 K; despite the isostructural property of BaLa2CuO5 and BaNd5CuO5, the Nd-analog was found to be antiferromagnetic. As x in Ba(Nd2-xLax)CuO5 increases between 0 and 2, the amount of ferromagnetism increases

  10. Phase equilibria in SmS-In2S3, SmSe-In23Se3 and SmTe-In2Te3 systems

    International Nuclear Information System (INIS)

    Phase equilibria are studied for the first time and state diagrams of SmS-In2S3, SmSe-In23Se3 and SmTe-In2Te3 systems are plotted for the first time using physicochemical analysis techniques. Formations of SmIn2S4, SmIN-4S7, SmIn2Se4 and SmIn2Te4 composition samarium chalcoindates and limited ranges of solubility characteristic for indium sesqui-chalcogenites are determined. SmIn2S4 compound is melted congruently under 1570 K, while SmIn4S7, SmIn2Se4 and SmIn2Te4 are formed by peritectic reaction

  11. Nitrate ion association with Sm3+ ion

    International Nuclear Information System (INIS)

    A solvent extraction method with TBP as an extractant was used for the determination of the stability constants K10 for the SmNO32+ complex, for different least approach distances aa of ions. It was established that aa=6.5A for SmNO32+. (Author)

  12. The occurrence of the phase Sm Co C2 in Sm Co5 magnets

    International Nuclear Information System (INIS)

    Besides the matrix phase Sm Co5, it is commonly recognized that magnets of Sm Co 1:5 type present three other microstructural constituents: pores, oxides and Sm2 Co7. In addition to those, evidence is offered about the presence of another phase, Sm-Co raw-material powder contains about 0.03%C and it may be increased during milling, by reaction with the carbon-containing protection fluid. The Sm Co C2 carbide was identified by electron probe microanalysis, WDS and X-ray diffraction. (author)

  13. Study on rare earth/alkaline earth oxide-doped CeO2 solid electrolyte

    Institute of Scientific and Technical Information of China (English)

    YAN Kai; ZHEN Qiang; Song Xiwen

    2007-01-01

    Five types of rare earth/alkaline earth oxide-doped CeO2 superfine-powders were synthesized by a low-temperature combustion technique. The relevant solid electrolyte materials were also sintered by pressureless sintering at different temperatures. The results of X-ray diffraction and transmission electron microscopy showed that the grain size of the powders was approximately 20-30 nm, and rare earth/alkaline earth oxides were completely dissolved into ceria-based solid solution with fluorite structure. The electrical conductivities of the Sm2O3-CeO2 system were measured by the ac impedance technique in air at temperatures ranging from 513-900℃. The results indicated that the ionic conductivities of Sm0.20Ce0.8O1.875 solid electrolyte increase with increasing sintering temperature, and the relationship between the conductivities and measuring temperature obeys the Arrhenius equation. Then the Sm2O3-CeO2 material was further doped with other rare earth/alkaline earth oxide, and the conductivities improve with the effective index.

  14. Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson at muon collider

    Indian Academy of Sciences (India)

    Jai Kumar Singhal; Sardar Singh; Ashok K Nagawat

    2007-06-01

    We explore the possibility of distinguishing the SM-like MSSM Higgs boson from the SM Higgs boson via Higgs boson pair production at future muon collider. We study the behavior of the production cross-section in SM and MSSM with Higgs boson mass for various MSSM parameters tan and A. We observe that at fixed CM energy, in the SM, the total cross-section increases with the increase in Higgs boson mass whereas this trend is reversed for the MSSM. The changes that occur for the MSSM in comparison to the SM predictions are quantified in terms of the relative percentage deviation in cross-section. The observed deviations in cross-section for different choices of Higgs boson masses suggest that the measurements of the cross-section could possibly distinguish the SM-like MSSM Higgs boson from the SM Higgs boson.

  15. On the role of Sm in solidification of Al-Sm metallic glasses

    CERN Document Server

    Bokas, G B; Perepezko, J H; Szlufarska, I

    2016-01-01

    During the solidification of Al-Sm metallic glasses the evolution of the supercooled liquid atomic structure has been identified with an increasing population of icosahedral-like clusters with increasing Sm concentration. These clusters exhibit slower kinetics compared to the remaining clusters in the liquid leading to enhanced amorphous phase stability and glass forming ability (GFA). Maximum icosahedral-ordering and atomic packing density have been found for the Al90Sm10 and Al85Sm15 alloys, respectively, whereas minimum cohesive energy has been found for the Al93Sm7 which is consistent with the range of compositions (from Al92Sm8 to Al84Sm16) found experimentally with high GFA.

  16. Temperature and host dependence of the transition interference between f–f and f–d transitions of Sm2+ in matlockites

    International Nuclear Information System (INIS)

    The absorption spectra of Sm2+ doped in MFX (M=Sr, Ba; X=Cl, Br) crystals were studied within the range of 20,000–35,000 cm−1 as a function of temperature and host. The absorption bands observed were described with a simple model developed by Wood and Kaiser using group theory. The temperature and host dependence on the 7F0→5D3 Fano resonance lines were investigated. BaFCl:Sm2+ system showed a “normal” 7F0→5D3 transition at 4 K in spite of similar crystal structure and absorption profile with other MFX hosts. New Fano resonances were observed in the absorption spectra at higher energies (23,000–25,000 cm−1) for all MFX:Sm2+ systems at 4 K which persist up to room temperature. Preliminary energy level calculation showed that these resonance lines involve the interaction between higher excited 5LJ states of 4f6 configuration and 4f55d1 configuration. - Highlights: • The absorption spectra of Sm2+ doped in MFX (M=Sr, Ba; X=Cl, Br) crystals within the range of as a function of temperature and host. • The absorption bands described with a simple model developed by Wood and Kaiser using group theory. • BaFCl:Sm2+ system showed a “normal” 7F0→5D3 transition at 4 K in spite of similar crystal structure and absorption profile with other MFX hosts. • New Fano resonances observed in the absorption spectra at higher energies (23,000–25,000 cm−1) for all MFX:Sm2+ systems at 4 K which persist up to room temperature

  17. Radioluminescence properties of Sm-doped fluorochlorozirconate glasses and glass-ceramics

    Science.gov (United States)

    Okada, Go; Edgar, Andy; Kasap, Safa; Yanagida, Takayuki

    2016-02-01

    We have investigated X-ray induced radioluminescence (XL) properties of Sm-doped fluorochlorozirconate (FCZ) glasses and glass-ceramics. The FCZ glass is a modified ZBLAN glass which shows a very high optical transmission over a wide spectral range. The glass matrix includes Sm3+-doped nanocrystals of BaCl2 after heat-treatment at temperatures above 250 °C. The glass-ceramic emits red light under UV and X-ray exposure. Since conventional Si-based photodetectors, e.g., CCDs, have the highest quantum efficiency to red light in general, the Sm-doped FCZ glass-ceramic plate can be a good candidate as a scintillator material for indirect radiation detection. Moreover, a very broad emission is present in the glass-ceramic around 300-500 nm, which is attributed to a self-trapped exciton (STE) emissions. The temperature dependence of X-ray induced luminescence and photoluminescence are very similar. The XL light yield is linearly proportional to the X-ray exposure rate for rates higher than 20 mR/s. For low exposure rates, emissions by Sm2+ are more sensitive than others, leading to a nonlinear response.

  18. Luminescence and spectroscopic properties of Sm2+ and Er3+ doped SrI2

    International Nuclear Information System (INIS)

    The scintillation and luminescence properties of SrI2:1% Sm2+ and SrI2:1% Er3+ are reported. Single crystals were grown by the vertical Bridgman technique. Broad band Sm2+ 5d–4f emission was observed centered at 750 nm with a radiative lifetime of 1.25 µs. The photoluminescence decay time increases with temperature due to self-absorption. With Er3+ a clear charge transfer band was identified at 295 nm. The spectroscopic properties of Sm2+ and Er3+ are compared with those of Eu2+, Yb2+, Ce3+, and Nd3+ doped in SrI2. The results are combined to construct a diagram with the vacuum referred electron binding energies for all divalent and trivalent lanthanide ions in SrI2 which is fully consistent with the spectroscopic observations. - Highlights: • 750nm 5d–4f emission has been observed for Sm2+ in SrI2. • A valence band to Er3+ charge band has been observed for Er3+ in SrI2. • A binding energy diagram has been constructed from data on lanthanides in SrI2

  19. CE-BEMS

    DEFF Research Database (Denmark)

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

    2016-01-01

    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...

  20. Electronic configurations of Sm2+ in SmS and SmB6, and electrical properties

    International Nuclear Information System (INIS)

    In Dirac's theory the 4f shell is divided into two subshells: 4f/sub 5/2/ with six quantum states and 4f/sub 7/2/ with eight quantum states. Assuming that these two subshells can be filled up successively, we had successfully obtained the saturation magnetic moment of the garnets Ln3Fe5O12. This study is devoted to establish the role of the subshells in the case of SmS phase transformation under pressure P. Particularly for Sm2+ the low spin configuration 4f/sub 5/2/6 4f/sub 7/2/0 which with six 4f electrons has a filled subshell 4f/sub 5/2/ leading to a zero magnetic moment. But as the insulator in equilibrium metal I in equilibrium M transition exhibited with this phase transition, is explained through a valence change, we first consider the localized electron model proposed in the case of Fe3O4 to show that large variations of electrical resistivity of SmS and SmB6 also can be understood through this model. A result which allows us to consider the ion Sm2+ in both phases of SmS. 1 figure

  1. Phase equilibria and magnetic properties of iron-rich Fe-Nd-Ti and Fe-Sm-Ti alloys

    International Nuclear Information System (INIS)

    In Fe-Nd-Ti and Fe-Sm-Ti the phase with the hexagonal structure of Co5R is stabilized by the addition of Ti and has a rare-earth content just above 12 at. %, but well below 16.7 at. %, so that it must be classified as a Cu7Tb type. It and Fe17R2 dissolve approximately 3 at. % Ti, accompanied by an increase in Curie temperature in the latter. In Fe-Nd-Ti the phase with the tetragonal Mn12Th structure is found near Fe11TiNd, and its low-anisotropy field is verified. It forms in the cast alloys and is stable only above 1000 degree C. At 1000 degree C and below it decomposes according to Fe11TiNd→Fe17Nd2 +Fe2Ti+Fe. In Fe-Ti-Sm the high-anisotropy phase Fe11TiSm does not undergo this decomposition down to 700 degree C, but it is restricted by the coexistence of Fe17Sm2 and Fe2Ti. As a result, Fe11TiSm is found accompanied by either free Fe or easy-plane Fe17Sm2. A new phase Fe9.5Ti1.5Sm has the structure of tetragonal Ce(Mn,Ni)11 with a=0.8253 and c=0.4825 nm; it has no permanent magnetic moment at room temperature. The high-anisotropy phase near Fe70Ti10Sm20 is not observed between the melting temperature and 700 degree C

  2. Interaction in the systems Bi2S3-SmS and Bi2S3-Sm2S3

    International Nuclear Information System (INIS)

    Methods of physicochemical analysis are used to study Bi2S3-SmS (1) and Bi2S3-Sm2S3 (2) systems that are quasibinary cross sections of Sm-Bi-S ternary system. Formation of ternary phases of SmBi2S4, SmBi4S7 (in system 1) composition and of SmBiS3 composition (in system 2) is stated. The compounds are crystallized in stibnite type rhombic singony: SmBi2S4: a = 12.55; b = 14.11; c = 4.12 A; SmBi4S7: a = 12.61; b = 14.20, c = 4.70 A, SmBiS3: a 11.15, b = 11.77, c = 3.85 A. SmS(Sm2S3) solubility in Bi2S3 at 300 K is 3 mol.%

  3. Hydrides of intermetallic compounds R3Ni8Al (R=Sm, Tu, Lu)

    International Nuclear Information System (INIS)

    Interaction of hydrogen with intermetallic compounds (IC) R3Ni8Al (R=Sm, Tu, Lu) with the structure of Ce3Co8Si type was studied. Formation of hydride Sm3Ni8AlH11.7 takes place at a high rate and it is accompanied by increase in the volume of unit cell of IC structure by 23 %. According to the data of X-ray diffraction study the volume of unit cells of hydride structure [Tu, Lu]3Ni8AlHx (1) is 0.7-1.2 % higher than the volume of unit cells of the structures of intermetallic compounds. Thermal decomposition of hydride takes place in two stages at 340-390 K, and that of hydride phase of (1) - in one stage at 340 and 450 K respectively

  4. Thermodynamic properties of Sm2S3 and SmS2 within wide temperature range

    International Nuclear Information System (INIS)

    For the first time using the mixing method in a wide temperature range inthalpies of Sm2S3 and SmS2 are determined. An intense increase of Sm2S3 enthalpy is observed in the high temperature range and the melting point for this compound is determined. The basic thermodynamic characteristics (enthalpy, thermal capacity, entropy, reduced Gibbs energy) of studied sulfides are calculated

  5. About defect structure in SmS

    International Nuclear Information System (INIS)

    One managed to obtain the experimental dependence of the conduction band electron concentration on the sizes of X-ray radiation coherent scattering regions. The curve analysis was based on the previously elaborated concentration model of SmS energy spectrum. The impurity donor levels in SmS were shown to correlate with samarium defective ions located at the boundaries of the coherent scattering regions

  6. Fusiblility diagram of the SmS-Sm2S3 system

    International Nuclear Information System (INIS)

    Isobaric fusibility diagram of a part of the binary Sm-S system lying between SmS-Sm2S3 compounds within 1500-2100 deg C temperature range was built on the basis of the data of physicochemical analysis (thermal, annealing and quenching, microstructural, durometric and X-ray phase). Consistency of data from different methods indicates at the reliability and confidence of the presented diagram. The analogy of Sm-S system fusibility diagram with La-S system diagram is noted

  7. Provably-secure (Chinese government) SM2 and simplified SM2 key exchange protocols.

    Science.gov (United States)

    Yang, Ang; Nam, Junghyun; Kim, Moonseong; Choo, Kim-Kwang Raymond

    2014-01-01

    We revisit the SM2 protocol, which is widely used in Chinese commercial applications and by Chinese government agencies. Although it is by now standard practice for protocol designers to provide security proofs in widely accepted security models in order to assure protocol implementers of their security properties, the SM2 protocol does not have a proof of security. In this paper, we prove the security of the SM2 protocol in the widely accepted indistinguishability-based Bellare-Rogaway model under the elliptic curve discrete logarithm problem (ECDLP) assumption. We also present a simplified and more efficient version of the SM2 protocol with an accompanying security proof. PMID:25276863

  8. Sm3+-doped alkaline earth borate glasses as UV→visible photon conversion layer for solar cells

    International Nuclear Information System (INIS)

    Intense multi-peak red fluorescence emissions of Sm3+ are exhibited in alkaline-earth borate (LKZBSB) glasses under UV radiation. The spontaneous emission probabilities Arad corresponding to the 4G5/2→6HJ (J=5/2, 7/2, 9/2 and 11/2) transitions are derived to be 24.74, 129.72, 117.03 and 32.23 s−1, respectively, and the relevant stimulated emission cross-sections σem are 0.77×10−22, 4.46×10−22, 5.05×10−22 and 1.38×10−22 cm2, confirming the effectiveness of red luminescence in Sm3+-doped LKZBSB glasses. Quantitative characterization through the evaluation of absolute spectral parameters reveals that the quantum yield of Sm3+-doped LKZBSB glasses is as high as 13.29%. Furthermore, with the introduction of Ce3+, the effective excitation wavelength range and the emission intensity of Sm3+ in LKZBSB glasses are remarkably expanded and improved by a maximum sensitization factor of 9.02 in the UVB region. These results demonstrate that the present glass system has promising potential as an efficient UV→visible photon conversion layer for the enhancement of solar cell efficiency, including appealing applications in outer space. - Highlights: • Intense multi-peak red fluorescence emissions of Sm3+ are exhibited under UV radiation. • Effectiveness of red luminescence is confirmed by stimulated emission cross-sections. • Quantum yield of Sm3+-doped LKZBSB glasses is 13.29% by quantitative characterization. • Effective excitation wavelength range and emission intensity are improved with Ce3+ doping. • Alkaline-earth borate glass has potential as solar cell UV→Vis photon conversion layer

  9. Superconducting and magnetic properties of new ternary borides with the CeCo3B2-type structure

    International Nuclear Information System (INIS)

    Four new ternary boride systems with the CeCo3B2-type structure are reported with the general formulae: MRu3B2 (M = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Th or U), MRh3B2 (M = La, Ce, Pr, Nd, Sm, Eu or Gd), MOs3B2 (M = Lu or U) and MIr3B2 (M = La, Th or U). Most members of these systems were found to become either superconducting or magnetically ordered. The structure and properties of these materials are discussed in relation to those of other ternary systems previously reported to exhibit superconductivity and/or magnetic order. (author)

  10. Superconducting and magnetic properties of new ternary borides with the CeCo 3B 2-type structure

    Science.gov (United States)

    Ku, H. C.; Meisner, G. P.; Acker, F.; Johnston, D. C.

    1980-07-01

    Four new ternary boride systems with the CeCo 3B 2-type structure are reported with the general formulae: MRu 3B 2 (M = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Th or U), MRh 3B 2 (M = La, Ce, Pr, Nd, Sm, Eu or Gd), MOs 3B 2 (M = Lu or U) and MIr 3B 2 (M = La, Th or U). Most members of these systems were found to become either superconducting or magnetically ordered. The structure and properties of these materials are discussed in relation to those of other ternary systems previously reported to exhibit superconductivity and/or magnetic order.

  11. Mixed valent perovskites Ba3B3+Ru2sup(4.5+)O9

    International Nuclear Information System (INIS)

    The black compounds Ba3B3+Ru2O9 crystallize with B3+ = La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Y in a hexagonal BaTiO3 structure (6L, sequence (hcc)2) with an ordered distribution (1:2 order) of B3+ and ruthenium (BO6 single octahedra; Ru2O9 double groups). The mean oxidation state of ruthenium is about +4.5. The properties are compared with those of other isotypic stacking polytypes Ba3B3+M2sup(4.5)O9 (M2 = IrRu, Ir2, PtRu) and Ba3B2+M25+O9 (M = Ru, Ir). The results of activity tests concerning the efficiency of perovskite oxides with noble metals in respect of the oxidation of CO or CHsub(x) and the reduction of NOsub(x) are reported. (author)

  12. Curie temperature rising by fluorination for Sm2Fe17

    Directory of Open Access Journals (Sweden)

    Matahiro Komuro

    2013-02-01

    Full Text Available Fluorine atoms can be introduced to Sm2Fe17 using XeF2 below 423 K. The resulting fluorinated Sm2Fe17 powders have ferromagnetic phases containing Sm2Fe17FY1(0Sm2Fe17FY2 (1Sm2Fe17, and α-Fe. The unit cell for Sm2Fe17 is elongated by the fluorination. The largest unit cell volume among the rhombohedral Sm2Fe17 compounds is 83.8 nm3, which is 5.8% larger than Sm2Fe17. The rhombohedral Sm2Fe17 with the largest unit cell volume is dissociated above 873 K, and fluorination increases Curie temperature from 403 K for Sm2Fe17 to 675 K. This increase can be explained by the magneto-volume effect.

  13. Effects of Cerium Doping at Ti Sites and Europium Doping at Ba Sites on Dielectric Properties of BaTiO3 Ceramics

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Two special rare earth elements cerium and europium were chosen to conduct chemical modification of the BaTiO3 structure. The cold-pressing ceramic processing technique was used to prepare barium titanate ceramics doped with Ce at Ti sites and with Eu at Ba sites on the base of formulas Ba(Ti1-xCex)O3(x=0.05, 0.10)(CBT) and(Ba1-yEuy)Ti1-y/8O3(y=0.05, 0.10)(EBT). Associated with structures and microstructures, the effects of cerium and europium doping on dielectric properties of BaTiO3 ceramics were discussed. The CBT ceramics exhibit a pseudo-cubic perovskite structure, while the EBT ceramics exhibit a tetragonal perovskite structure with the exception of the existence of a small percentage of the Eu2Ti2O7 phase. The Curie peak of BaTiO3 shifts towards room temperature at rates of 3 ℃/mol Ce atoms and 10 ℃/mol Eu atoms(Eu≤5%), respectively. Compared with the CBT ceramics, the EBT ceramics show significant advantages, such as a narrow fine grain size distribution(1 μm), a lower porosity and a higher density(5.85 g/cm3), more stable dielectric-temperature dependence(ε'=1600-1800 at t<50 ℃) and a lower dissipation factor(<0.05). The stability of dielectric constant with frequency in BaTiO3 can extend to 107 Hz due to Ce and Eu doping.

  14. Optimization of the Time Response of LaBr3(Ce) Detectors, and Its Dependence on Ce Concentration

    Science.gov (United States)

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

    Fast inorganic scintillators that exhibit good spectroscopy performance, like LaBr3(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 [1]. This method, which is very sensitive to the LaBr3(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 [2]. In this work we have searched for the best settings in order to optimize the time resolution of three cylindrical LaBr3(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 BaF2 detector, whose time response is well known. The LaBr3(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 60Co and 22Na energies.

  15. Magnetic and structural properties of SmCo7-xTix magnets

    International Nuclear Information System (INIS)

    The main phase in as-cast SmCo7-xTix (x=0.3, 0.4, 0.5, 0.6) magnets is found to have the TbCu7-type structure. The c/a ratio decreases with increasing Ti concentration x, but the unit cell volume increase with x. A minor amount of a rhombohedral Th2Zn17-type phase was detected at x=0.3, 0.4, and an another Ce2Ni7-type phase with low Curie temperature appeared when x exceeds 0.5. No more than 0.1 T of intrinsic coercivity was obtained in the as-cast samples. After annealing, the TbCu7-type SmCo7-xTix magnets decomposed into 1 : 5 and 2 : 17 phases, with a slight increase in coercivity compared with the corresponding as-cast samples up to a maximum of 0.24 T. The as-milled amorphous SmCo7-xTix magnets recrystallised with TbCu7-type structure after annealing at 750 deg. C for 2 h. High intrinsic coercivities of more than 2.0 T were obtained for almost all compositions, and maximum coercivity of 2.5 T was found for the ball-milled SmCo6.6Ti0.4 magnet. The high coercivity of the ball-milled SmCo7-xTix magnets is attributed to the strong pinning of the walls of the 'interaction domains' by the network of grain boundaries between the nanocrystalline grains

  16. Structure and physical properties of single crystal PrCr2Al20 and CeM2Al20 (M=V, Cr): A comparison of compounds adopting the CeCr2Al20 structure type

    International Nuclear Information System (INIS)

    Crystal growth and full structure determination of compounds adopting the CeCr2Al20 structure type, LnTi2Al20 (Ln=La–Pr, Sm, and Yb), LnV2Al20 (Ln=La–Pr, and Sm), and LnCr2Al20 (Ln=La–Pr, Sm, and Yb), are reported. Resistivity, magnetic susceptibility, and heat capacity of flux grown single crystals of the nonmagnetic CeM2Al20 (Ln=Ce, Yb; M=Ti, V) compounds are compared to PrCr2Al20. Of particular interest is PrCr2Al20 which does not show any phase transition down to the lowest temperature of the measurement (400 mK in resistivity measurement and 1.8 K for magnetic susceptibility measurements) and exhibits Kondo behavior at low temperatures. - Graphical abstract: Crystal structure of SmV2Al20 showing the interpenetrating diamond-like samarium network and pyrochlore-like vanadium network. Highlights: ► Single crystals of LnM2Al20 were grown from a molten aluminum flux. ► Magnetic, electrical, and specific heat of single crystal LnM2Al20 are presented. ► PrCr2Al20 exhibits evidence of Kondo effect.

  17. Smärta och smärtlindring hos äldre : -en litteraturstudie

    OpenAIRE

    Kjellberg, Karin

    2012-01-01

    Detta examensarbete är en litteraturstudie om de äldres upplevelser av smärta och metoder för smärtlindring. Uppdragsgivare för detta arbete är Esbo Hemvård. Andelen äldre ökar kraftigt och ändå är hälsorelaterade frågor för den här människogruppen ofta försummade. Syftet med studien var att belysa äldres upplevelser av smärta, beskriva vilka metoder för smärtlindring de äldre föredrar och vad vårdare kan göra för att lindra smärta hos dessa personer. Forskningsfrågor för den här studien var:...

  18. FT-IR evaluation of SmFeAsO1-xFx (x = 0, 0.069)

    Science.gov (United States)

    Shinohara, Hajime; Kamihara, Yoichi

    2012-02-01

    Optical properties of superconducting SmFeAsO1-xFx (x=0, 0.069) were demonstrated by reflection measurement with FT- IR method. Polycrystalline SmFeAsO1-xFx samples were synthesized using two-step solid state reaction described elsewhere [New J. Phys.12, 033005 (2010)]. Purity of samples was checked by X-ray diffraction patterns using Cu K- alpha radiation. The reflection measurement was performed at the range from 9000 cm-1 to 18000 cm-1 that was corresponded to an energy region from 1.12 eV to 2.25 eV. A photoconductivity of SmFeAsO1-xFx was determined by Kramer-Kroning (KK) relation. Reflectivity and photoconductivity measurements, as well as by FT-IR, at various areas were performed to define an energy level of materials [EPL, 84 67013 (2008), and J. Phys. Soc. Jpn. 80 013707 (2011)]. Obtained photoconductivity and reflection spectra were similar to those of LaFeAsO1-xFx that was a basic compound of LnFeAsO1-xFx (Ln=La, Ce, Sm), reported by Z. G. Chen et al [Phys. Rev. B 81, 100502 (2010)]. Our result suggests that the energy band structure of SmFeAsO was affected by F-doping even in visible area. Details and temperature dependence of the reflection and photoconductivity spectra will be presented at the conference.

  19. Nioboaeschynite-(Ce, Ce(NbTiO6

    Directory of Open Access Journals (Sweden)

    Shaunna M. Morrison

    2012-08-01

    Full Text Available Nioboaeschynite-(Ce, ideally Ce(NbTiO6 [cerium(III niobium(V titanium(IV hexaoxide; refined formula of the natural sample is Ca0.25Ce0.79(Nb1.14Ti0.86O6], belongs to the aeschynite mineral group which is characterized by the general formula AB2(O,OH6, where eight-coordinated A is a rare earth element, Ca, Th or Fe, and six-coordinated B is Ti, Nb, Ta or W. The general structural feature of nioboaeschynite-(Ce resembles that of the other members of the aeschynite group. It is characterized by edge-sharing dimers of [(Nb,TiO6] octahedra which share corners to form a three-dimensional framework, with the A sites located in channels parallel to the b axis. The average A—O and B—O bond lengths in nioboaeschynite-(Ce are 2.471 and 1.993 Å, respectively. Moreover, another eight-coordinated site, designated as the C site, is also located in the channels and is partially occupied by A-type cations. Additionally, the refinement revealed a splitting of the A site, with Ca displaced slightly from Ce (0.266 Å apart, presumably resulting from the crystal-chemical differences between the Ce3+ and Ca2+ cations.

  20. Navrhování asfaltových směsí a zkoušení odolnosti proti tvorbě trvalých deformací

    OpenAIRE

    Dlouhý, Petr

    2013-01-01

    Bakalářská práce se zabývá zkoušením vstupních materiálů pro návrh asfaltových směsí, kde byly provedeny zkoušky kameniva a asfaltového pojiva. Následně proběhlo navržení dvou asfaltových směsí, české směsi ACO 11+ a německé směsi AC 11 DS. Tyto směsi byly dále zkoušeny na odolnost proti tvorbě trvalých deformaci. Dosažené výsledky byly vzájemně porovnány.

  1. Alkaline-earth oxide network modifier on optical properties of Ce3+-activated borogermanate glasses

    Science.gov (United States)

    Sun, Xin-Yuan; Xiao, Zhuo-Hao; Zhong, Jiu-Ping

    2015-12-01

    Transparent and colorless CeO2-activated borogermanate glasses, with the nominal composition of 25B2O3-40GeO2-14Gd2O3-1CeO2-20MO (M = Ba, Sr, Ca and Mg), were synthesized by a melt-quenching method in air. Their optical properties including the transmittance, photoluminescence (excitation and emission spectra), the luminescence decay curves, as well as the temperature-dependent emission spectra were studied in detail. The room temperature photoluminescence spectra reveal that the emission intensity of the MgO glass is about two times stronger than that of the BaO glass. The blue shift of the cut-off edge, excitation and emission spectra of Ce3+-activated borogermanate glass were clearly observed in the order of BaO, SrO, CaO and MgO. And the emission intensity of Ce3+ ions as a function of temperature range in 325-475 K was also investigated.

  2. Coherent potential approximation treatment of the Sm valence transition in SmS induced by alloying

    International Nuclear Information System (INIS)

    The Sm valence transition, similar to the pressure-induced transition in pure SmS, has been observed in a large number of cases by substituting a trivalent rare earth, B, for Sm, thereby forming isostructural alloys with a lattice constant smaller than that of semiconducting SmS. Such substitutions are expected to exert a 'chemical' pressure which simulates the external pressure. However, divalent substitutions (Yb, Eu and Ca), although having a favourable 'size' factor, do not induce any valence transition. Accordingly, band structure effects, essentially due to the relative position of the conduction bands of SmS and BS, should also be taken into consideration. In order to clarify the role which the lattice constant and the electronic structure play in the valence transition, these alloys have been studied using the coherent potential approximation (CPA) including both the crystal field effect and the Coulomb interaction between localised and itinerant states as driving mechanisms. For Sm, the 'homogeneous' picture is considered, each Sm site having the average valence; then the Smsub(1-x)Bsub(x)S system is reduced to a binary alloy. Charge transfer between the f states of Sm and the alloy conduction band (i.e. Sm valence change) is determined self-consistently. The calculations are consistent with the experimental behaviour and allow us to understand qualitatively the variation of the critical concentration xsub(c) for the transition as a function of the difference Δa between the lattice parameters of SmS and BS. (author)

  3. Brillouin spectroscopy on doped SmS

    International Nuclear Information System (INIS)

    SmS becomes intermediate valent at an applied pressure of about 6.5 kbar. On the other hand, SmS doped with La or Tm is already intermediate valent at normal pressure and room temperature. The doping atoms (depending on their concentration) create new occupied states in the SmS gap which lead to the typical hybridised 4fi/4fi-1-5d1-states. The La-cation is always trivalent in LaS, whereas the Tm-cation has a valence between 2 and 3. Therefore, we expect to see a difference in the intermediate valent behaviour. A strong evidence of intermediate valence is a negative C12 and a negative Poisson's ratio. Using high-resolution Brillouin-spectroscopy we measured the phase velocity of the surface acoustic waves in the (100)-plane of Sm1-xLaxS and Sm1-xTmxS. Applying a standard fit-algorithm we calculated all three elastic constants (C11, C12 and C44) from the angular dispersion relation. To get more reliable results the compression-moduli also have been determined and linked to the elastic constants C11 and C12 in the fit model. (orig.)

  4. Revisiting the β-decay of 139Ba

    International Nuclear Information System (INIS)

    Spectroscopy of 139La is important for understanding the collective and the single particle states as it is one of the nuclei with N = 82 shell closure. The energy levels of 139La had been investigated either by the EC (electron capture) of 139Ce or by the γ-decay of 139Ba. As the QEC for 139Ce is 270 keV, only the ground and the first excited states in 139La are populated, thus only a limited information can be established from this decay-mode. On the other hand in 139Ba: approximately 99.7% of its β decay populates the ground and the first excited states in 139La, only a small fraction populates the other levels. These facts have been reflected in the scarcity of detailed experimental information on other/higher excited levels of 139La, which has led to certain discrepancies in the previous works. In the present work, the β-decay of 139Ba has been investigated, to obtain information on the energy levels and associated γ-rays of the daughter 139La

  5. Conductivity-independent Fano Effect of the Ba (Ag) Phonon in R0.5Pr0.5Ba2Cu3O7

    International Nuclear Information System (INIS)

    The Fano effect of the Ba (Ag) line is clearly pronounced and remains nearly the same through the whole series R0.5Pr0.5Ba2Cu3O7 (R=Lu, Yb, Tm, Er, Ho, Y, Dy, Gd, Eu, Sm, Nd, Pr, La) which undergoes a superconductor-to-nonsuperconductor transition between R = Dy and Gd. The scattering background that interfere with the Ba (Ag) phonon is therefore not related to the carriers responsible for the superconductivity. Rather, the continuum of electronic transitions near EF between or within the 'plane' bands of mainly O4 (apex oxygen) character in the vicinity of the S point of the Brillouin zone have to be considered. (author)

  6. Triaxiality in 146,148Sm nuclei

    International Nuclear Information System (INIS)

    Recently, attempts have been made to use the dynamic pairing plus quadrupole model to evaluate B(E2) values, B(E2) branching ratios, and low-lying energy levels for 146,148Sm nuclei, which are in poor agreement with experiment. Application of the boson expansion technique on 148Sm shows too much splitting and an incorrect order for the quintet states, while other properties have not been discussed. In the present work, 146,148Sm nuclei have been described using an asymmetric rotor model framework. The nonaxiality parameter γ has been evaluated using the energy ration E2+'/E6+. Remarkable success has been achieved in explaining the correct ordering of known low-lying energy levels, B(E2) values, and B(E2) branching ratios, which indicate that the so-called spherical nuclei may be treated as triaxial. (author). 8 refs., 9 tabs., 1 fig

  7. Resonant photoemission from SmS(100)

    International Nuclear Information System (INIS)

    A strong, sharp resonance enhancement of 4f photoemission has been observed on SmS(100) surfaces for photon energies in the region of the 4d-4f transitions at about 126 eV. The discrete final state reached via the excitation hν + 4d104f6 → 4d94f7 autoionizes primarily via a super Coster-Kronig transition of the type 4d94f7 → 4d104f5 + unbound electron. Other decay channels, e.g. Sm 5p emission, as well as a surface induce binding energy shift in the Sm3+ final state are identified and discussed. (author)

  8. The Cloud2SM Project

    Science.gov (United States)

    Crinière, Antoine; Dumoulin, Jean; Mevel, Laurent; Andrade-Barosso, Guillermo; Simonin, Matthieu

    2015-04-01

    From the past decades the monitoring of civil engineering structure became a major field of research and development process in the domains of modelling and integrated instrumentation. This increasing of interest can be attributed in part to the need of controlling the aging of such structures and on the other hand to the need to optimize maintenance costs. From this standpoint the project Cloud2SM (Cloud architecture design for Structural Monitoring with in-line Sensors and Models tasking), has been launched to develop a robust information system able to assess the long term monitoring of civil engineering structures as well as interfacing various sensors and data. The specificity of such architecture is to be based on the notion of data processing through physical or statistical models. Thus the data processing, whether material or mathematical, can be seen here as a resource of the main architecture. The project can be divided in various items: -The sensors and their measurement process: Those items provide data to the main architecture and can embed storage or computational resources. Dependent of onboard capacity and the amount of data generated it can be distinguished heavy and light sensors. - The storage resources: Based on the cloud concept this resource can store at least two types of data, raw data and processed ones. - The computational resources: This item includes embedded "pseudo real time" resources as the dedicated computer cluster or computational resources. - The models: Used for the conversion of raw data to meaningful data. Those types of resources inform the system of their needs they can be seen as independents blocks of the system. - The user interface: This item can be divided in various HMI to assess maintaining operation on the sensors or pop-up some information to the user. - The demonstrators: The structures themselves. This project follows previous research works initiated in the European project ISTIMES [1]. It includes the infrared

  9. Specific heat in high magnetic fields. A study of the heavy-fermion systems U(Pt,Pd)3 and CeRu2Si2 and the high-Tc superconductors ReBa2Cu2O7. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    van der Meulen, H.P.

    1992-06-02

    The subject of the thesis is the study of the low-temperature electronic behavior of two classes of materials: the high-T(c) superconductor YBa2Cu3O7 with rare-earth substitutions for Y, and the heavy-fermion compounds U(Pt,Pd)3 and CeRu2Si2. The thesis is organized as follows: In chapter 2, the experimental technique for performing specific-heat measurements in high static magnetic fields are discussed. In addition, a paper on new possibilities of magnetic ripple shielding for specific heat measurements in hybrid magnets is presented. Chapter 3 is devoted to the high-T(c) superconductors of the series REBa2Cu3O7. In chapter 4, the low-temperature specific heat of REBa2Cu3O7, as studied in magnetic fields up to 5 T, is presented. The authors discuss measurements from which information about the crystal-field level schemes of the rare-earth ions can be derived. Chapter 5 is devoted to specific-heat studies in the heavy-fermion superconductor UPt3, and in the Pd-substituted U(Pt1-xPdx)3 compounds, with x=0.05 and 0.10. Chapter 6 describes the field suppression of the heavy-fermion state in CeRu2Si2.

  10. Decay of 120Ba

    International Nuclear Information System (INIS)

    The decay of 120Ba has been studied with an on-line isotope separator. Its half-life was determined to be t1/2=24±2 s. A decay scheme is proposed, based on γ-γ, γ-X, and γ-β+ coincidence measurements, which takes account of all 16 observed γ rays. The total decay energy was measured to be QEC=50±0.3 MeV

  11. Life-limiting mechanisms in Ba-oxide, Ba-dispenser and Ba-Scandate cathodes

    Science.gov (United States)

    Gaertner, G.; Barratt, D.

    2005-09-01

    Ba-oxide, Ba-dispenser and Ba-Scandate cathodes have been continuously improved in their emission performance in the past decades. Ba-oxide and Ba-dispenser cathodes are also the dominant types of thermionic cathodes used in most vacuum tube applications. When improvements in emissive properties are introduced, their impact on cathode life - where several years in a vacuum tube environment are typically required - also needs to be known. Hence, the investigation of cathode life-limiting effects is the basis of accelerated life predictions and of further cathode improvement. In this contribution, the main effects limiting the operating life of Ba/BaO-based thermionic cathodes are discussed, especially related to intrinsic dispensation and resupply to the emissive surface. Emission poisoning induced by adsorption of poisonous gases will not be addressed here. We will stress common points and point out the differences between the three types.

  12. Ce que soigner veut dire

    OpenAIRE

    Mol, Annemarie

    2013-01-01

    Qu'est-ce que bien soigner? Dans ce livre provoquant et original, Annemarie Mol montre que ce n'est pas, comme on l'a beaucoup dit, laisser les patients choisir. À partir de l'exemple des personnes atteintes de diabète, l'auteur propose une nouvelle manière de prendre soin des personnes, qui ne les transforme pas en citoyens ou en consommateurs, mais qui les reconnaît comme corps et âmes souffrants, comme individus investis dans leur propre prise en charge, comme membres de collectifs multipl...

  13. Conceptual Design Plan SM-43 Replacement Project

    Energy Technology Data Exchange (ETDEWEB)

    University of California, Los Alamos National Laboratory, SCC Project Office

    2000-11-01

    The Los Alamos National Laboratory Conceptual Design Plan for the SM-43 Replacement Project outlines plans for replacing the SM-43 Administration Building. Topics include the reasons that replacement is considered a necessity; the roles of the various project sponsors; and descriptions of the proposed site and facilities. Also covered in this proposal is preliminary information on the project schedule, cost estimates, acquisition strategy, risk assessment, NEPA strategy, safety strategy, and safeguards and security. Spreadsheets provide further detail on space requirements, project schedules, and cost estimates.

  14. Rotational hysteresis in SmCo5

    International Nuclear Information System (INIS)

    Torque curves of SmCo5 sintered magnets with regularily lowered coercivity up to a maximum field H = 28 x 105 Am-1 have been registered automatically. From the observed rotational hysteresis the values of the rotational integral could be estimated in dependence on the degree of lowering of the coercivity. By comparison with theoretically calculated values for a simple nucleation model for a single crystal it follows that the mechanism of the magnetization reversal for SmCo5 magnets with lowered coercivity should be pinning of Bloch walls in the multidomain state. The absolute value of the maximum rotational hysteresis work is comparable with the maximum linear hysteresis work. (author)

  15. Krager, husskader og småvildt

    DEFF Research Database (Denmark)

    Asferg, T.

    på kragers og husskaders præda-tion på hare, ager-høne og fasan med særlig fokus på perioden fra det tidlige forår til jagtsæsonens start i efteråret. Derudover er der en kort opsummering af prædationen på småfugle. Mange eksperimenter har vist, at prædation på det jagtbare småvildt kan reduceres...

  16. Návrh směsi typu asfaltový beton a stanovení odolnosti proti účinkům vody

    OpenAIRE

    Renza, Jaroslav

    2014-01-01

    Tato bakalářská práce popisuje a zkouší asfaltové směsi typu asfaltový beton podle návrhu národní přílohy revidované normy ČSN EN 13108-1 Asfaltový beton. V návaznosti na návrhy směsi byla porovnána její odolnost proti účinkům vody.

  17. Dopant Behaviours of Sm2O3 on Microstructure and Properties of Barium Zirconium Titanate Ceramics

    Institute of Scientific and Technical Information of China (English)

    王永力; 李龙土; 齐建全; 桂治轮

    2001-01-01

    The effect of Sm2O3-dopant on the sintering characteristics and dielectric properties of barium zirconium titanate ceramics (BaZrxTi1-xO3) was investigated. It is shown that trace amount of Sm2O3 can greatly affect the grain growth and densification of barium zirconium titanate ceramics during sintering. At the same time, the dielectric peak at high temperature shifts to lower temperature and that at low temperature shifts to higher temperature. The two dielectric peaks overlap with each other when the Sm2O3-dopant content varies from 0.25% to 1%, and the maximum relative dielectric constant is greatly enhanced. These effects may be attributed to the substitution actions of the rare earth element in perovskite lattice. At the doping content of 0.75%, the dielectric constant maximum of 23570 can be obtained. By adopting some proper additives, an excellent Y5V dielective material is obtained, and the room temperature properties are as follows: relative dielectric constant εRT≥23,000, dielectric loss tgδ≤0.0075 and the breakdown strength under alternating field Eb≥5 kV·mm-1.

  18. Struktury budoucích směrovacích tabulek pro IPv6

    OpenAIRE

    Kšica, Martin

    2010-01-01

    Tato práce se zabývá strukturami budoucích směrovacích tabulek protokolu IPv6. Obsahuje základní informace o IPv6 adresách, popis hierarchického přidělování adres, multihoming, strategie přidělování IPv4/IPv6 adres, statistiky vlastností vyskytující se ve strukturách směrovacích tabulek a předpověď budoucího adresového prostoru protokolu IPv6. Součástí práce je implementace generátoru IPv6 adres, který generuje adresy podle zadané konfigurace. Současně lze v práci nalézt průzkum strategií při...

  19. Mechanism of high-temperature protonic conductivity in the SrCeO3 oxides

    International Nuclear Information System (INIS)

    In the framework of a model of a small-radius protonic polaron with a strong proton-phonon bond, the temperature dependence of protons mobility, doping effect on electric conductivity, dependence of activation energy on lattice parameters and oxygen sublattice dynamics have been studied theoretically in compounds on the basis of SrCeO3, SrZrO3 and BaCeO3. A good agreement between calculated and experimental dependences has been attained. It suggests the presence of a strong polaronic effect in the compounds studied

  20. Comparison of Ce$^{3+}$ and Pr$^{3+}$ activators in alkaline-earth fluoride crystals

    OpenAIRE

    Radzhabov, E.; Nepomnyaschikh, A.

    2012-01-01

    The emission spectra of Ce$^{3+}$ or Pr$^{3+}$ doped CaF$_2$, SrF$_2$, BaF$_2$ excited by vacuum ultraviolet photons or by x-ray as well as excitation and absorption spectra in vacuum ultraviolet region (6-13 eV) were studied. The transfer of exciton energy is the main channel for Ce$^{3+}$ excitation in alkaline-earth fluorides. Three different stages of energy transfer were observed. Pr$^{3+}$ excited by two processes, slow f-f luminescence excited by excitons, fast d-f luminescence excited...

  1. Signature splitting in 129Ce

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  2. Effective thickness of CeO2 buffer layer for YBCO coated conductor by advanced TFA-MOD process

    International Nuclear Information System (INIS)

    YBCO films were fabricated on PLD-CeO2/IBAD-Gd2Zr2O7/Hastelloy substrates using the advanced TFA-MOD process. The effective thickness of the CeO2 buffer layer for obtaining high Ic was investigated in short samples of YBCO films. The CeO2 buffer layer was epitaxially grown on an IBAD-Gd2Zr2O7 template tape with 18 deg. of Δφ by a reel-to-reel PLD system. The in-plane grain alignment of PLD-CeO2 buffer layers rapidly improved with the thickness and saturated at a critical thickness of 0.8 μm. The size of CeO2 grains was about 1 μm at the saturated thickness of Δφ. YBCO films with the thickness of 1 μm were deposited by the TFA-MOD on the CeO2 buffer layer with different thickness films. Improvement of the CeO2 in-plane grain alignment resulted in increase of Ic. The Ic values of 250-290 A were obtained with the CeO2 layer thicker than 0.8 μm. The CeO2 thickness, at which the intensity ratio of the BaCeO3 was saturated, corresponded to the critical thickness. From the view points of achieving higher production rates and to obtain the CeO2 Δφ value of 5 deg. as well as considering the reaction between YBCO and CeO2, the optimum thickness of the CeO2 buffer layer on the IBAD-Gd2Zr2O7 with 18 deg. of Δφ was found to be at least 0.8 μm

  3. Hydrothermal alteration of monazite-(Ce) from the Santa Maria de Itabira pegmatite district (Minas Gerais, Brazil); Alteration hydrothermale des monazites-(Ce) des pegmatites du district de Santa Maria de Itabira (Minas Gerais, Bresil)

    Energy Technology Data Exchange (ETDEWEB)

    Bilal, E.; Arias Nalini, H.; Nasraoui, M. [Ecole Nationale Superieure des Mines, 42 - Saint-Etienne (France). Dept. de Geochimie, Centre SPIN; Marciano, V.; Neves, J.M.C.; Fernandes, M.L. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Inst. Geociencias; Fuzikawa, K. [Comissao Nacional de Energia Nuclear (CNEN), Belo Horizonte, MG (Brazil). Centro de Desenvolvimento de Tecnologia Nuclear

    1998-05-01

    Monazite-(Ce) is found in granitic pegmatites in the Santa Maria de Itabira pegmatite district (Minas Gerais, Brazil). During the magmatic stage, monazite-(Ce) seems to have had higher contents of cheralite and buttonite in the solid solution. The Th content in primary monazite-(Ce) is high and characteristic for each pegmatite body. During the late stage (albitisation), the mean LREE content in the altered zone is slightly higher and Th content is very low. The accessory mineral assemblages changed; buttonite and cheralite crystallize together with Th-poor and La-rich monazite-(Ce) at the border of altered crystals. Nd/Sm and U/Pb ratios also changed during the hydrothermal stage. (authors) 13 refs.

  4. Determination of half-life of the 155Sm β-decay

    International Nuclear Information System (INIS)

    Full text: The half-lives of some nuclides are of high importance, especially for calculations regarding the nuclear fallout in nuclear accidents. Rare-earth elements, like Eu and Ce, in the form of oxides dissolved in irradiated nuclear fuel are non-volatile and released with difficulty during an accident, making their isotopes important in the investigation of radioecological studies. There are many codes to calculate these radioisotopes activities in nuclear reactors, but to make these inventories, all the feeding chain must be known. Particularly, 155Eu is formed by direct fission process, neutron capture of 154Eu and beta decay of 155Sm. The last process have a short half life and the correct value is an important information for the activity calculation. In this work, the half-life of the 155Sm β decay was determined using enriched 154Sm samples submitted to irradiation in the IEA-R1 reactor of IPEN; the activity of the samples were followed for 4-5 consecutive half lives using a 198cm3 HPGe detector. The data was corrected using a non paralizable dead time correction and fitted to an exponential decay function using a non linear fitting procedure developed on the MatLab platform. The resulting value was compatible to the one found in the literature, with a lower uncertainty. (author)

  5. Structure and electrical properties of (Bi1/2Na1/2)0.94−x(Li1/2Ce1/2)xBa0.06TiO3 lead-free piezoelectric ceramics

    International Nuclear Information System (INIS)

    Lead-free piezoelectric ceramics BNT-BT6-LCx has been successfully synthesized by the conventional solid-state reaction method. All BNT-BT6-LCx ceramics form the pure perovskite phase structure, and no obvious change in the crystal structure is observed with the addition of (Li1/2Ce1/2). Transition temperature Tm is found to be no obvious change and Td decreases continuously with x. Composition with x=0.010 has shown the optimum ferroelectric and piezoelectric properties with low value of Ec, which are as follows: Pr=32.65 μC/cm2, Ec=41 kV/cm and d33=163 pC/N

  6. Specific heat of REBaSrCu3O7 compounds (R=Nd, Sm, Dy, Er)

    International Nuclear Information System (INIS)

    Specific heat measurements have been performed on polycrystalline REBaSrCu3O7 (R=Nd, Sm, Dy, Er) in the temperature range from 0.3 to 3 K. Antiferromagnetic order is indicated by the λ-type peak in the specific heat at 1.2 and 0.6 K for Dy and Er compounds, respectively, whereas only a broad anomaly around 0.6 K is observed for Nd and Sm compounds. The specific heat data for Nd and Sm compounds are well fit with a Schottky-type anomaly with an energy splitting of 1.4 K, indicating the existence of an internal field of 2.42 T at the RE site. The magnetic singlet ground state of ErBaSrCu3O7 and DyBaSrCu3O7 is produ ced by exchange interactions of -0.05 and -0.035 T f.u./μB, respectively. (orig.)

  7. Effect of burnable poison addition on the thermo-mechanical properties of UO2-5wt5CeO2 pellets

    International Nuclear Information System (INIS)

    The microstructural characteristics and the thermo-mechanical properties of the pellets were evaluated and compared for UO2 and UO2-5wt%CeO2 pellets doped with burnable poisons (5wt% and 10wt% of Gd2O3, Sm2O3 and Dy2O3), sintered in reducing atmosphere for 4h. The sintered density and the grain size of UO2 and UO2-5wt%CeO2 pellets decreased by adding Gd2O3, Sm2O3 and Dy2O3 and the Vickers handness (Hv) of these pellets were found not affected with density and grain size variations. The fracture toughness (KIC) of the UO2 pellets increased with Gd2O3 and Dy2O3 adding and decreased with 10wt% Sm2O3 but that of UO2-5wt%CeO2 pellets were not changed. The fracture strength (of) of UO2 and UO2-5wt%CeO2 pellets were not affected by addition of burnable poison material and the critical thermal shock temperature difference (ΔTc) of the pellets increased for UO2 pellets doped with Gd2O3. Sm2O3 and Dy2O3 in the low temperature range (80 ∼ 200 .deg. C)

  8. New states in SmS

    International Nuclear Information System (INIS)

    Quasihydrostatic pressure resistivity experiments on a single crystal of SmS are reported up to 27.5 kbar. At low temperature, a regime change occurs at P approximately 20 kbar, between a ''quasiinsulating'' behavior (P 20 kbar). Striking similarities appear with TmSe and TmS cases. (author)

  9. SmAHTR-CTC Neutronic Design

    Energy Technology Data Exchange (ETDEWEB)

    Ilas, Dan [ORNL; Holcomb, David Eugene [ORNL; Gehin, Jess C [ORNL

    2014-01-01

    Building on prior experience for the 2010 initial SmAHTR neutronic design and on 2012 neutronic design for the advanced high temperature reactor (AHTR), this paper presents the main results of the neutronic design effort for the newly re-purposed SmAHTR-CTC reactor concept. The results are obtained based on full-core simulations performed with SCALE6.1. The dimensionality of the SmAHTR design space is reduced by using constraints originating in material fabricability, fuel licensing, molten salt chemistry, thermal-hydraulic and mechanical considerations. The new design represents in many regards a substantial improvement from the neutronic performance standpoint over the 2010 SmAHTR concept. Among other results, it is shown that fuel cycle length of over 2 years or discharged fuel burnup of 40GWd/MTHM are possible with a low, 8% fuel enrichment in a once-through fuel cycle, while 8-year once-through fuel cycle lengths are possible at higher fuel enrichments.

  10. Hydrothermal alteration of monazite-(Ce) from the Santa Maria de Itabira pegmatite district (Minas Gerais, Brazil)

    International Nuclear Information System (INIS)

    Monazite-(Ce) is found in granitic pegmatites in the Santa Maria de Itabira pegmatite district (Minas Gerais, Brazil). During the magmatic stage, monazite-(Ce) seems to have had higher contents of cheralite and buttonite in the solid solution. The Th content in primary monazite-(Ce) is high and characteristic for each pegmatite body. During the late stage (albitisation), the mean LREE content in the altered zone is slightly higher and Th content is very low. The accessory mineral assemblages changed; buttonite and cheralite crystallize together with Th-poor and La-rich monazite-(Ce) at the border of altered crystals. Nd/Sm and U/Pb ratios also changed during the hydrothermal stage. (authors)

  11. Preparation and quality control of {sup 153}Sm radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Swasono, R. Tamat; Widyastuti, W.; Purwadi, B.; Laksmi, I. [Radioisotope Production Center - BATAN, Jakarta (Indonesia)

    1998-10-01

    The paper summarizes the preparation and quality control of {sup 153}Sm-EDTMP and three {sup 153}Sm-radiosynovectomy agents. Natural and enriched Sm{sub 2}O{sub 3} (98.7% {sup 152}Sm) irradiated in RSG-GAS 30 MW reactor yielded pure and high specific activity {sup 153}Sm. Labeling of EDTMP with {sup 153}Sm was carried out by mixing {sup 153}SmCl{sub 3} solution of pH 4.0 to an EDTMP solution at room temperature then pH adjustment to 8. The {sup 153}Sm-EDTMP complex was separated from the free {sup 153}Sm{sup +3} on a Chelex 100 column. Radiochemical purity was determined by thin layer chromatography using Cellulose sheets and pyridine: ethanol: water (1: 2: 4) mixture as solvent. The {sup 153}Sm-EDTMP has been shown to be stable for two weeks. Three particulate preparations of {sup 153}Sm used for the irradiation of chronic synovitis have been studied. They are hydroxyapatite particles, human serum albumin microspheres and ferric hydroxide macroaggregates. The {sup 153}Sm-ferric hydroxide macroaggregates were prepared in a single step by coprecipitation of {sup 153}Sm in the formation of Fe(OH){sub 3}. Preparation of {sup 153}Sm-labelled hydroxyapatite particles and {sup 153}Sm-labelled albumin microspheres were carried out by {sup 153}Sm labelling of previously prepared particles. Radiolabelling efficiency were greater than 95% for hydroxyapatite particles and macroaggregates and was lower than 20% for albumin microspheres. The particle sizes were inspected using an optical microscope with a haemocytometer and micrometric ocular. (author)

  12. Intermediate valent metallic SmS and SmSe: a new puzzle

    International Nuclear Information System (INIS)

    It has been discovered that the R-T characteristic of so-called metallic SmS decreases with decreasing T at low temperatures for pressures exceeding approximately equal to kbar. This feature is reminiscent of a metal and in sharp contrast to the previously reported negative temperature coefficient at 10 and 20 kbar. The same fundamental change of the R-T dependence occurs in SmSe at approximately equal to 100 kbar. (author)

  13. Luminescence in LaBaB{sub 9}O{sub 16} prepared by combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Sonekar, R.P.; Omanwar, S.K. [Department of Physics, Sant Gadgebaba Amravati University, Amravati (India); Moharil, S.V., E-mail: svmoharil@yahoo.co [Department of Physics, Rashtrasant Tukdoji Maharaj Nagpur University, Nagpur (India); Muthal, P.L.; Dhopte, S.M.; Kondawar, V.K. [National Environmental Engineering Research Institute, Nehru Marg, Nagpur (India)

    2009-06-15

    LaBaB{sub 9}O{sub 16} phosphors activated by various ions belonging to ns{sup 2}, 3d{sup n} and 4f{sup n} configurations were prepared by combustion synthesis. Phosphors' synthesis and luminescence spectra are reported. Most of the activators displayed intense characteristic emission. Pr{sup 3+}->Gd{sup 3+}, Ce{sup 3+}->Tb{sup 3+}, Ce{sup 3+}->Dy{sup 3+}, Ce{sup 3+}->Mn{sup 2+} and Bi{sup 3+}->Mn{sup 2+} energy transfers were also observed. In particular, Ce{sup 3+}->Tb{sup 3+} energy transfer leads to an efficient green emitting phosphor.

  14. (RE)BaCuO/Ag composites: fundamentals of processing, microstructure and control of properties

    International Nuclear Information System (INIS)

    We have investigated the phase equilibria in (RE)BaCuO-Ag systems, the influence of Ag on the processing of (RE)BaCuO/Ag composites and the resulting properties. YBCO/Ag composites have been grown by the modified melt crystallization process with YBa2Cu3O7, Y2O3, Pt and Ag2O in the precursor. The improved strength of the YBCO/Ag composites compared with the conventional YBCO bulk material permitted us to magnetize these materials to achieve trapped fields up to 16 T (at 24 K) in the gap of a mini-magnet. The investigation of the microstructure revealed a remarkable increase of the spacing between micro-cracks especially of those perpendicular to a-b planes when 12 wt% Ag was added. In the case of SmBaCuO/Ag composites Ag has a strong influence on processing and causes interactions between RE123 seeds and the sample. We report on the growth of single-grain SmBaCuO/Ag composites in air and we discuss the influence of post-annealing on increasing Tc and jc. (author)

  15. Diagnostic significance of Schistosoma mansoni proteins Sm31 and Sm32 in human schistosomiasis in an endemic area in Egypt.

    Science.gov (United States)

    El-Sayed, L H; Ghoneim, H; Demian, S R; El-Sayed, M H; Tawfik, N M; Sakr, I; Abou-Basha, L M; Renganathan, E; Klinkert, M Q; Abou-Rawash, N

    1998-09-01

    We performed a series of ELISAs to evaluate the diagnostic significance of two Schistosoma mansoni proteins, Sm31 (cysteine proteinase, cathepsin B) and Sm32 (asparaginyl endopeptidase). Our study populations were chosen from two villages in an endemic area close to Alexandria. Using fusion proteins MS2-Sm31 and MS2-Sm32 as antigens, 70% and 78.9%, respectively, of patient sera from 134 parasitologically confirmed cases reacted positively. The percentage of seropositivity increased to 84.5% when parasite-derived proteins Sm31 and Sm32 were used. The serum levels of antibodies to these two proteins in recombinant or native forms do not correlate with intensity of infection and hence are detected even when egg counts are low, which makes proteins Sm31 and Sm32 useful antigens in the identification of S. mansoni infected cases, particularly in endemic areas in Egypt. PMID:9754667

  16. Evaluation of SmCo and SmCoN magnetron sputtering coatings for SOFC interconnect applications

    Science.gov (United States)

    Wu, Junwei; Li, Chengming; Johnson, Christopher; Liu, Xingbo

    Cobalt or cobalt containing coatings are promising for SOFC interconnect applications because of their high conductivity. We have investigated SmCo and SmCoN coatings deposited by magnetron sputtering from a SmCo (5% Sm) target on to Crofer 22 APU substrates. The composition, structure, surface morphology, and electrical conductivity of the coated substrates were characterized by SEM/EDX, XRD and ASR measurements. Addition of Sm enhances the oxidation resistance and the Cr retention capability of the coatings. The use of nitride as a precursor stabilizes Sm during oxidation of the films, thus inhibiting diffusion of Fe, resulting in a more compact coating and lowering ASR. The combined advantages of Sm addition to cobalt and the use of a nitride as a precursor, makes SmCoN coatings a promising new interconnect coating material.

  17. Návrh vnitropodnikových směrnic pro vedení účetnictví v příspěvkové organizaci

    OpenAIRE

    Jedonová, Radana

    2009-01-01

    Bakalářská práce je zaměřená na problematiku vnitropodnikových směrnic pro vedení účetnictví příspěvkové organizace. V úvodní části je provedena analýza legislativních požadavků souvisejících s danou problematikou. Dále práce analyzuje již vypracované účetní směrnice organizace a poukazuje na jejich reálné nedostatky. Cílem práce je zefektivnění, aktualizace a zlepšení účetních směrnic. V závěrečné části bakalářské práce jsou vypracované nové účetní směrnice potřebné pro vnitřní řízení organi...

  18. Leptonic B Decays at BaBar

    Energy Technology Data Exchange (ETDEWEB)

    Baracchini, Elisabetta; /Rome U. /INFN, Rome

    2011-11-10

    We will present the most recent results on leptonic B decays B{sup {+-}(0)} {yields} K*{sup {+-}(0)}{nu}{bar {nu}} and B{sup {+-}} {yields} {mu}{sup {+-}}{nu}, based on the data collected by the BaBar detector at PEP-II, an asymmetric e{sup +}e{sup -} collider at the center of mass energy of the {Upsilon}(4S) resonance. Rare B decays have always been a standard probe for New Physics (NP) searches. The very low Standard Model (SM) rate of these decays often make them unaccessible with the present experimental datasets, unless NP effects enhance the rate up to the current experimental sensitivity. Moreover, as NP effects can modify the decay kinematic, particular attention must be paid in order to perform a model independent analysis. A B-Factory provides an unique environment to investigate these processes. The high number of B{bar B} pairs produced by a B-Factory often allows to approach the needed experimental sensitivity. Moreover, the clean environment and the closed kinematic of the initial state enable to obtaining a very pure sample where to look for these decays.

  19. Leptonic B Decays at BaBar

    Energy Technology Data Exchange (ETDEWEB)

    Monorchio, Diego; /INFN, Naples /Naples U.

    2011-09-13

    The authors will present the most recent results on leptonic B decays B{sup {+-}(0)} {yields} K*{sup {+-}(0)} {nu}{bar {nu}} and B{sup {+-}} {yields} {mu}{sup {+-}}{nu}, based on the data collected by the BaBar detector at PEP-II, an asymmetric e{sup +}e{sup -} collider at the center of mass energy of the {Upsilon}(4S) resonance. Rare B decays have always been a standard probe for New Physics (NP) searches. The very low Standard Model (SM) rate of these decays often make them unaccessible with the present experimental datasets, unless NP effects enhance the rate up to the current experimental sensitivity. Moreover, as NP effects can modify the decay kinematic, particular attention must be payed in order to perform a model independent analysis. A B-Factory provides an unique environment where to investigate these processes. The high number of B{bar B} pairs produced by a B-Factory often allows to approach the needed experimental sensitivity. Moreover, the clean environment and the closed kinematic of the initial state enable to obtaining a very pure sample where to look for these decays.

  20. Performance of LaBaCo 2O 5+ δ-Ag with B 2O 3-Bi 2O 3-PbO frit composite cathodes for intermediate-temperature solid oxide fuel cells

    Science.gov (United States)

    Li, Ruifeng; Gao, Lei; Ge, Lin; Zheng, Yifeng; Zhou, Ming; Chen, Han; Guo, Lucun

    The composite cathodes LaBaCo 2O 5+ δ- x wt.% Ag (LBCO- xAg, x = 20, 30, 40, 50) were prepared by mechanical mixing method for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The experiment results indicated that the addition of a small amount of B 2O 3-Bi 2O 3-PbO (BBP) frit to LBCO- xAg can effectively improve the adhesion and strength of cathode membrane without damaging its porous structure. The BBP frit was proved effective for lowering the sintering temperature of LBCO- xAg to 900 °C. According to the electrochemical impedance spectroscopy and cathodic polarization analysis, the LBCO-30Ag exhibited the best performance and the optimal BBP frit content was 2.5 wt.%. For LBCO-30Ag with 2.5 wt.% BBP frit, the area-specific resistance based on Sm 0.2Ce 0.8O 1.9 (SDC) electrolyte decreased by about 57.6% at 700 °C, 60.5% at 750 °C and 75.9% at 800 °C compared to LBCO, and its cathodic overpotential was 10.7 mV at a current density of 0.2 A cm -2 at 700 °C, while the corresponding value for LBCO was 51.0 mV. The addition of Ag and BBP frit to LBCO had no significant effect on the thermal expansion.

  1. Layered perovskite oxide Y0.8Ca0.2BaCoFeO5+δas a novel cathode material for intermediate-temperature solid oxide fuel cells

    Institute of Scientific and Technical Information of China (English)

    余良浩; 陈永红; 顾庆文; 田冬; 卢肖永; 孟广耀; 林彬

    2015-01-01

    A layered perovskite oxide Y0.8Ca0.2BaCoFeO5+δ(YCBCF) was synthesized as a novel cathode material for intermedi-ate-temperature solid oxide fuel cells (IT-SOFCs) by citric acid-nitrates self-propagating combustion method. The phase and micro-structure of YCBCF were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The aver-age thermal expansion coefficient (TEC) of YCBCF was 14.6×10–6 K–1, which was close to other materials of SOFC at the range of RT–1000 ºC. An open-circuit potential of 0.75 V and a maximum output power density of 426 mW/cm2 were obtained at 650 ºC in a Sm0.2Ce0.8O1.9 (SDC)-based anode-supported SOFC by using humidified (~3%H2O) hydrogen as fuel and static air as oxidant. The results indicated that the YCBCF was a promising cathode candidate for IT-SOFCs.

  2. SmS-Ga2S3 system

    International Nuclear Information System (INIS)

    The system SmS-Ga2S3 was studied by physico-chemical methods and diagrams of state drawn up. It was established that the compounds SmGa2S4 and SmGa4S7 were formed in the system. Orthorhombic (a=10.28, b=10.42, c=6.16 A, space group Bmbm) and monoclinic symetries are determined for SmGa2S4 and SmGa4S7 single crystals respectively

  3. A-site calcium-doped Pr1-xCaxBaCo2O5+δ double perovskites as cathodes for intermediate-temperature solid oxide fuel cells

    Science.gov (United States)

    Fu, Dawei; Jin, Fangjun; He, Tianmin

    2016-05-01

    The LnBaCo2O5+δ (Ln = rare earth) double perovskite cathodes possess superior electrochemical performance in intermediate-temperature solid oxide fuel cells (IT-SOFCs). However, high thermal expansion coefficients (TECs) and material costs are major challenges to their widespread applications. In this paper, a novel A-site Ca doping strategy that can suppress the spin-state transition of Co3+ is proposed to reduce the TECs and material costs of Pr1-xCaxBaCo2O5+δ (x = 0.1-0.4; PCBCO). Substitution of Ca for Pr effectively reduces the TEC from 22.2 × 10-6 K-1 at x = 0.1 to 19.1 × 10-6 K-1 at x = 0.3 between 100 and 800 °C. PCBCO exhibits good chemical compatibility with the Sm0.2Ce0.8O1.9 (SDC) electrolyte. The area-specific resistances of PCBCO cathodes with x = 0.1, 0.2, and 0.3 are 0.081, 0.082, and 0.089 Ω cm2, respectively, at 700 °C on the SDC electrolyte. The maximum power densities of a single cell on a 0.3 mm-thick SDC electrolyte reach 646.5, 636.8, and 620.6 mW cm-2 at 800 °C for cathodes with x = 0.1, 0.2, and 0.3, respectively. The PCBCO double perovskites exhibit excellent chemical compatibility and electrochemical performance while reducing the TECs and material costs; thus, these double perovskites are promising cathode materials for applications in IT-SOFCs.

  4. Octupole collectivity in the Sm isotopes

    International Nuclear Information System (INIS)

    Microscopic models suggest the occurrence of strong octupole correlations in nuclei with N≅88. To examine the signatures of octupole correlations in this region, the spdf interacting boson approximation model is applied to Sm isotopes with N=86-92. The effects of including multiple negative-parity bosons in this basis are compared with more standard one negative-parity boson calculations and are analyzed in terms of signatures for strong octupole correlations. It is found that multiple negative-parity bosons are needed to describe properties at medium spin. Bands with strong octupole correlations (multiple negative-parity bosons) become yrast at medium spin in 148,150Sm. This region shares some similarities with the light actinides, where strong octupole correlations were also found at medium spin

  5. Vliv směsí "Green solvents" a nanočástic na vybrané polymerní povrchové úpravy

    OpenAIRE

    Rektořík Trhlíková, Lucie

    2012-01-01

    Práce je zaměřena na studium směsí rozpouštědel typu "green" a nanočástic při interakci s vybranými polymerními povrchovými úpravami. Hodnotí se odolnost povrchových úprav proti účinku směsí rozpouštědel s přídavkem přípravků s nanočásticemi a odstranitelnost vybraných nečistot z povlaků typu polyvinylchlorid, polyuretan a polyester pomocí rozpouštědel na bázi směsných esterů.

  6. Lattice dynamics of γ--Ce

    International Nuclear Information System (INIS)

    The phonon and magnetic measurements described in the thesis produced the following significant results concerning the lattice dynamical and magnetic properties of γ-Ce. The phonon spectrum is relatively soft, which is consistent with results obtained for CeSn3. The L [110] and T [111] branches of the dispersion curve are anomalous. The C11 and C44 elastic constants are quite close in value. No discrete magnetic excitations were observed. The magnetic scattering is qualitatively similar to the results from Ce0.74Th0.26, however, GAMMA/sub Ce/ less than GAMMA/sub Ce-Th/. The various lattice dynamical and magnetic similarities among γ-Ce, CeSn3, and Ce0.74Th0.26 are mixed valence compounds. Therefore, a complete theoretical description of the observed properties of Ce and its compounds may provide a basis for understanding a whole class of mixed valence materials

  7. Transport properties of golden SmS

    International Nuclear Information System (INIS)

    We report electrical resistivity and Hall effect measurements on golden SmS up to a pressure of P∼26kbar. The Hall coefficient at a low temperature shows a drastic decrease above about 13 kbar as a function of P, and a change in sign at a critical pressure Pc2 above which an antiferromagnetically ordered phase appears. We construct a P-T phase diagram from the transport properties together with previously reported results of the ac magnetic susceptibility

  8. Instability of SmS under pressure

    International Nuclear Information System (INIS)

    It is suggested that electron-phonon (EP) interaction is a suitable mechanism to explain the instability of the semiconducting phase in SmS under pressure. The f reversible d and d reversible d scattering processes due to EP interaction avoid the introduction of negative renormalized f-d hybridization assumed by some other models as the source of the first order instability. Moreover this instability is shown as occuring for a non-zero energy gap. (orig.)

  9. The SM-200 step motor control device

    International Nuclear Information System (INIS)

    One of the main nodes of the stand for testing and modeling solenoid coils, which define the focus of the beam of charged particles in the accelerator LUE-200 (IREN), is a device for positioning Hall sensors (HS). The mechanism of movement of the platform where HS are installed is activated by the step motor. This paper describes the control device of the step motor SM-200

  10. Energy levels of Sm2+ excited state

    International Nuclear Information System (INIS)

    The energy levels of excited configurations 4f5u'l' of Sm2+ calculated in detail by using unitary group approach are covered. The energy expressions with slater integral as parameters are given and the spin-orbit coupling is considered according to the Russell-Saunders approximation. The coupling parameters λ of the main energy levels are also calculated in the paper

  11. X(5 Symmetry to 152Sm

    Directory of Open Access Journals (Sweden)

    Eid S. A.

    2016-07-01

    Full Text Available The excited positive and negative parity states, potential energy surfaces, V ( ; , electromagnetic transition probabilities, B ( E 1, B ( E 2, electric monopole strength X ( E 0 = E 2 and staggering e ect, I = 1, were calculated successfully using the inter- acting boson approximation model IBA -1. The calculated values are compared to the available experimental data and show reasonable agreement. The energy ratios and contour plot of the potential energy surfaces show that 152 Sm is an X (5 candidate.

  12. Lifetime measurement for the 21+ state in 140Sm and the onset of collectivity in neutron-deficient Sm isotopes

    Science.gov (United States)

    Bello Garrote, F. L.; Görgen, A.; Mierzejewski, J.; Mihai, C.; Delaroche, J. P.; Girod, M.; Libert, J.; Sahin, E.; Srebrny, J.; Abraham, T.; Eriksen, T. K.; Giacoppo, F.; Hagen, T. W.; Kisielinski, M.; Klintefjord, M.; Komorowska, M.; Kowalczyk, M.; Larsen, A. C.; Marchlewski, T.; Mitu, I. O.; Pascu, S.; Siem, S.; Stolarz, A.; Tornyi, T. G.

    2015-08-01

    Background: The chain of Sm isotopes exhibits a wide range of nuclear shapes and collective behavior. While the onset of deformation for N >82 has been well studied both experimentally and theoretically, fundamental data is lacking for some Sm isotopes with N Weisskopf units. The theoretical calculations are in very good agreement with the experimental result. Conclusions: The B (E 2 ;21+→01+) value for 140Sm fits smoothly into the systematic trend for the chain of Sm isotopes. The new beyond-mean field calculations are able to correctly describe the onset of collectivity in the Sm isotopes below the N =82 shell closure for the first time.

  13. Návrh kompozitového směrového kormidla pro letoun L 410 NG

    OpenAIRE

    Sokol, Filip

    2015-01-01

    Tato diplomová práce se zabývá návrhem kompozitní konstrukce směrového kormidla letounu L410 NG vycházející ze současné duralově-plátnové konstrukce. Podle předpisu FAR 23 a jeho oběžníků je navržen postup certifikace kompozitní primární konstrukce letounu. Je navržena konstrukce nového směrového kormidla a z vybraných materiálů proveden návrh skladby kompozitních materiálů. Programem MSC Patran je z této konstrukce vytvořen MKP model a pomocí softwarů Compost a Nastran provedena pevnostní ko...

  14. The Naturalness of the Fourth SM Family

    CERN Document Server

    Sultansoy, S

    2009-01-01

    The necessity of the fourth family follows from the SM basics. According to flavor democracy the Dirac masses of the fourth SM family fermions are almost equal with preferable value 450 GeV, which corresponds to common (for all fundamental fermions) Yukawa coupling equal to SU(2) gauge coupling gW. In principle, one expect u4 a little bit lighter than d4, while nu4 could be essentially lighter than l4 due to Majorana mass terms for right-handed components of neutrinos. Obviously, the fourth family quarks will be copiously produced at the LHC. However, the first indication of the fourth SM family may be provided by early Higgs boson observation due to almost an order enhancement of the gluon fusion to Higgs cross-section. For the same reason the Tevatron still has a chance to observe the Higgs boson before the LHC. Concerning the fourth family leptons, in general, best place will be NLC/CLIC. However, for some mass regions and MNS matrix elements double discovery of both the nu4 and H could be possible at the ...

  15. Electrochemical aspects of Ce+3 / Ce system in Flinak

    International Nuclear Information System (INIS)

    The voltammetric electrodeposition of cerium has been studied on three types of substrates - Ag, W and vitreous Carbon with the aim of know the mechanisms of the process. The Flinak - Ce F3 melt was used, with temperature range of 500-850O C. No alkaline metals co deposition was observed. (author)

  16. Effect of oxygen partial pressure on the morphology and properties of Ce doped YBCO films fabricated by a MOCVD process

    International Nuclear Information System (INIS)

    Rare-earth (RE) (e.g. Sm, Dy, Ce, etc.) doping has been widely investigated to improve critical current density (Jc) of YBa2Cu3O7-X (YBCO) coated conductors (CC). Oxygen partial pressure is known to be a key parameter in terms of affecting the Jc of YBCO films. In this work, the effect of oxygen partial pressure on the microstructure and Jc of a Ce doped YBCO film was examined. Ce doped YBCO films were deposited on (1 0 0) SrTiO3 (STO) single crystal substrates at oxygen partial pressures of 2.5, 5.0, and 10.0 Torr using a metal organic chemical vapor deposition (MOCVD) method. Due to the enhanced migration of surface adatoms under reduced oxygen partial pressure, a 1 wt% Ce doped YBCO film had a stoichiometric, dense surface. In addition, the zero-field Jc (at 77 K) of the 1 wt% Ce doped YBCO film deposited at reduced oxygen partial pressure was increased. Irrespective of the amount of Ce, the Ce doped YBCO film showed an increased zero-field Jc (at 77 K) under reduced oxygen partial pressure.

  17. Influence of modifier oxides on spectroscopic properties of Sm3+ doped lithium fluoroborate glass

    Science.gov (United States)

    Ratnakaram, Y. C.; Balakrishna, A.; Rajesh, D.; Seshadri, M.

    2012-11-01

    Sm3+ doped lithium fluoro-borate glasses with different modifier oxides (Li2B4O7-BaF2-NaF-MO where M = Mg, Ca, Cd and Pb) and combinations of modifier oxides (Li2B4O7-BaF2-NaF-MgO+CaO, Li2B4O7-BaF2-NaF-CdO+PbO) were prepared by means of melt quenching method. These samples were characterized by XRD, FTIR, optical absorption and fluorescence techniques at room temperature. The XRD profiles of all the glasses confirm their amorphous nature and the FTIR spectra reveal the presence of BO3 and BO4 units along with the strong OH- groups in the glass matrices. The influence of modifier oxides on Judd-Ofelt (J-O) intensity parameters and intensity of the emission lines are reported. Judd-Ofelt theory is used to study the spectral properties and to calculate the radiative transition probabilities (AT), branching ratios (βR), integrated absorption cross sections (Σ) and radiative lifetimes (τR) for certain spectral transitions. From the emission spectral analysis, emission cross-sections (σP) are calculated for the four emission transitions, 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2 and 4G5/2 → 6H11/2 of Sm3+ ion in different lithium fluoro-borate glasses. Among the four transitions, it is observed that the transition 4G5/2 → 6H7/2 has higher emission cross-section (σP) in all the glass matrices, except in Mg, Cd and Mg-Ca glass matrices. The non-exponential nature of the luminescence decay curves of 4G5/2 level of Sm3+ doped glass matrices are also reported.

  18. High-perfomance Ce-doped multicomponent garnet single crystalline film scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Zorenko, Yu.; Gorbenko, V.; Zorenko, T. [Institute of Physics, Kazimierz Wielki, University in Bydgoszcz, Powstancow, Wielkopolskich str., 2, 85090, Bydgoszcz (Poland); Department of Electronics of Ivan Franko, National University of Lviv, Gen. Tarnavskiy str. 17, 79017, Lviv (Ukraine); Sidletskiy, O. [Institute for Single Crystals, National Academy of Sciences of Ukraine, Lenina str., 60, 61001, Kharkiv (Ukraine); Fedorov, A. [SSI Institute for Single Crystals, National Academy of Sciences of Ukraine, Lenina str., 60, 61178, Kharkiv (Ukraine); Bilski, P.; Twardak, A. [Institute of Nuclear Physic, Polish Academy of Sciences, Radzikowskiego str., 176, 31-342, Krakow (Poland)

    2015-08-15

    We report for the first time the optimized content and excellent scintillation properties of single crystalline film (SCF) scintillators of multicomponent Gd{sub 3-x}Lu{sub x} Al{sub 5-y}Ga{sub y} O{sub 12}:Ce garnet compounds grown by liquid phase epitaxy (LPE) method. The Gd{sub 1.5}Lu{sub 1.5}Al{sub 2.75}Ga{sub 2.25}O{sub 12}:Ce and Gd{sub 3}Al{sub 2.75-2}Ga{sub 2.25-3}O{sub 12}:Ce SCF show the light yield (LY) comparable with that of high-quality bulk crystal analogues of these garnets but faster scintillation decay and very low thermoluminescence in the above room temperature range. To our knowledge, these SCF possess the highest LY values ever obtained in LPE grown garnet SCF scintillators exceeding by at least 1.5-1.6 times the values previously reported for SCF scintillators. Left figure: image of Gd{sub 1.5}Lu{sub 1.5}Al{sub 2.75}Ga{sub 2.25}O{sub 12}:Ce (PbO) (inset, left) and Gd{sub 3}Al{sub 2.35}Ga{sub 2.65}O{sub 12}:Ce (BaO) (inset, right) SCF scintillators, grown by LPE method onto Gd{sub 3}Al{sub 2.5}Ga{sub 2.5}O{sub 12} (GAGG) substrate; in the middle, green-yellow light emitting by Gd{sub 1.5}Lu{sub 1.5}Al{sub 2.75}Ga{sub 2.25}O{sub 12}:Ce (BaO) SCF under 350 nm laser illumination. Right figure: XRD pattern of (1200) planes of the Gd{sub 1.5}Lu{sub 1.5}Al{sub 2.75}Ga{sub 2.25}O{sub 12}:Ce (PbO) (black) and Gd{sub 3}Al{sub 2.75}Ga{sub 2.25}O{sub 12}:Ce (BaO) (red) SCFs, grown onto GAGG substrates. The film/substrate lattice misfit is -0.73% and -0.3%, respectively. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Ce3+ incorporated structural and magnetic properties of M type barium hexaferrites

    International Nuclear Information System (INIS)

    M type barium hexaferrites BaCexFe12−xO19 (0≤x≤0.3) (BCFO) were synthesized by the sol–gel auto combination method. Optimum annealing temperature of hexagonal phase was determined by using the TGA analysis. The annealing temperature form the TGA is 1000 °C samples annealed 1000 °C for 5 h to produce M type hexaferrites. X-ray diffraction data run to full Prof Program (Winploter 2010) pattern indicate that samples are single phase hexagonal structure with space group P63/mmc. Lattice parameter ‘a’ and ‘c’ increase with increase in Ce content x. Results of field emission scanning electron microscope show that the grains are regular hexagonal platelets with sizes from 0.3 to 1.4 μm. It is observed that from M–H curve value of the saturation magnetization and coercivity decreases with increasing x. Curie temperature from magnetization with temperature plot is found to decrease with Ce3+ substitution x due to decreases in magnetic interaction. - Highlights: • Ce3+ substituted Ba hexaferrites. • Increased coercivity with Ce3+ substitution. • Decrease in saturation magnetization and Curie temperature

  20. Problematika zvyšování podílu R - materiálu v asfaltových směsích

    OpenAIRE

    Urbanec, Luboš

    2013-01-01

    Předmětem této diplomové práce je problematika asfaltových směsí se zvyšujícím se podílem R-materiálu. V teoretické části práce jsou definovány pojmy recyklace a R-materiál a popsány druhy recyklace. Praktická část se věnuje výrobě a zkoušení asfaltových směsí s různým obsahem R-materiálu. Navrhovaná asfaltová směs je asfaltový beton pro podkladní vrstvy ACP22+. Obsah R-materiálu ve směsích je 0%, 30%, 50% a 70%. Jako speciální přísada pro změkčení asfaltu z R-materiálu se používá přísada STO...

  1. Characterization and activity of alkaline earth metals loaded CeO{sub 2}–MO{sub x} (M = Mn, Fe) mixed oxides in catalytic reduction of NO

    Energy Technology Data Exchange (ETDEWEB)

    Mousavi, Seyed Mahdi [Department of Applied Chemistry and Chemical Engineering, Faculty of Chemistry, University of Tabriz, 5166616471 Tabriz (Iran, Islamic Republic of); Niaei, Aligholi, E-mail: niaei@yahoo.com [Department of Applied Chemistry and Chemical Engineering, Faculty of Chemistry, University of Tabriz, 5166616471 Tabriz (Iran, Islamic Republic of); Illán Gómez, María José [Carbon Materials and Environment Research Group, Department of Inorganic Chemistry, Faculty of Science, Universidad de Alicante, Alicante (Spain); Salari, Dariush; Nakhostin Panahi, Parvaneh [Department of Applied Chemistry and Chemical Engineering, Faculty of Chemistry, University of Tabriz, 5166616471 Tabriz (Iran, Islamic Republic of); Abaladejo-Fuentes, Vicente [Carbon Materials and Environment Research Group, Department of Inorganic Chemistry, Faculty of Science, Universidad de Alicante, Alicante (Spain)

    2014-02-14

    Nanocrystalline CeO{sub 2}–MO{sub x} mixed oxides (M = Mn, Fe) with different M/(M + Ce) molar ratio are prepared by sol–gel combustion method. X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Temperature Programmed Reduction with H{sub 2} (H{sub 2}-TPR) and N{sub 2}-adsorption (BET) analyses are conducted to characterize the physical–chemical properties of the catalysts. The activity of catalysts for reduction of NOx with ammonia has been evaluated. The CeO{sub 2}–MnO{sub x} catalysts showed better low temperature activity than CeO{sub 2}–FeO{sub x}. The superior activity of CeO{sub 2}–MnO{sub x} with Mn/(Mn + Ce) molar ratio of 0.25 respect to other catalysts (with 83% NO conversion and 68% N{sub 2} yield at 200 °C) is associated to nanocrystalline structure, reducibility at low temperature and synergistic effect between Ce and Mn that are observed by XRD, TEM and H{sub 2}-TPR. The CeO{sub 2}–FeO{sub x} catalysts were found to be active at high temperature, being Ce–Fe the best catalyst yielded 82% NO conversion at 300 °C. The effect of alkaline earth metals (Ca, Mg, Sr and Ba) loading on the structure and catalytic activity of cerium mixed oxides are also investigated. Loading of Ba enhanced the NO reduction activity of mixed oxides due to the increase of number of basic sites. Highest performance with 91% NO conversion and 80% N{sub 2} yield attained over CeO{sub 2}–MnO{sub x} (0.25)-Ba (7%) catalyst at 200 °C. - Highlights: • CeO{sub 2}–MO{sub x} mixed oxides (M = Mn, Fe) were synthesized by sol–gel combustion method. • The activity of mixed oxides is evaluated in catalytic reduction of NO with NH{sub 3}. • The CeO{sub 2}–MnO{sub x} showed better activity than CeO{sub 2}–FeO{sub x} due to better redox properties. • Ba loading enhanced the activity due to the increase of number of basic sites. • 91% NO conversion and 80% N{sub 2} yield attained over 7%Ba–Ce{sub 0.75}Mn{sub 0.25}O{sub 2} at 200 °C.

  2. Connection of thermopower and giant magnetothermopower with magnetic and structural heterogeneity in Sm0.55Sr0.45MnO3 manganite

    International Nuclear Information System (INIS)

    It was first shown that the thermoelectric power in a magnetic semiconductor Sm0.55Sr0.45MnO3 is caused by ferromagnetic (FM) ferron-type nanoclusters and antiferromagnetic (AFM) CE-type nanoclusters with charge-orbital (CO) ordering. The presence of these clusters is caused by heavily Sr doping of a SmMnO3 compound, which replaced Sm ions. Thermoelectric power S and magnetothermopower ΔS/S has been studied in three samples: ceramics and two single-crystal samples. One of single-crystals was cooled in the air, another one was cooled in an oxygen atmosphere. The annealing in oxygen closes oxygen vacancies and, thus, increases the fraction of the CE-type AFM phase with the CO ordering which displaces the oxygen ions. S(T) curves of single-crystal sample cooled in the air and ceramic sample have a sharp increase starting from Curie temperature (TC) region and a slow decline till 325 K. At the same time {ΔS/S}(T) curves have a sharp minimum near TC=126 K, reaching the giant absolute value of 87% in the magnetic field H=14.17 kOe. This means that thermopower almost vanish with thermal destruction of FM clusters, i.e. thermopower is caused by these clusters in which crystal lattice is compressed. Oxygen cooled single-crystal's S(T) curves have a broad maximum near 270 K, including Neel temperature of CE-type clusters TNCE=240 K. {ΔS/S}(T) curve has a sharp minimum at the TNCE reaching the absolute value of 50% in H=13.2 kOe. The decrease of S is caused by destruction of CO order displacing oxygen ions in CE-type AFM clusters. Thus changed crystal lattice in nanoclusters of ferron type or AFM of CE-type makes the main contribution in thermopower in these three samples. - Highlights: • Thermopower S and magnetothermopower ΔS/S has been studied in Sm0.55Sr0.45MnO3. • Sample consists of ferromagnetic and antiferromagnetic (AF) CE-type clusters. • Maxima of S and |ΔS/S| were observed at Curie point in the samples cooled in the air. • Maxima were observed at

  3. On the microstructure of Sm Co5 magnets

    International Nuclear Information System (INIS)

    Sm Co5-based magnet microstructure is more complex than might be expected from the binary Sm-Co phase diagram, as other elements like oxygen and carbon intervene and as local heterogeneities occur due to the powder metallurgy method of production. This paper investigates the effect of sintering temperature, samarium and oxygen content on this microstructure and properties. Six constituents were found: Sm Co5, Sm2 Co7, oxides pores and the carbide Sm Co C2 are found in high coercivity magnets, whereas Sm2 Co17 is found in low coercivity magnets. A samarium-depleted surface region is always present and eventually large Co-rich particles occur. A microstructural modeling based on the magnetic density, samarium, oxygen and carbon content was able to predict the Sm2 Co7 volume fraction of magnets. The model permits the calculation of the necessary amount of Sm-rich additive to obtain high coercivity. The presence of Sm2 Co7 in the microstructure is not detrimental to high coercivity and high Hk, as Hk=12 kOe was obtained in samples with 7% volume fraction of Sm2 Co7. The effect to heat-treatment on coercivity is reversible: resintering with no heat-treatment lowers coercivity. As an oxygen solubility change was not found between 1150 and 850 deg C, it cannot be the cause of coercivity improvement due to heat-treatment. (author)

  4. Connection of thermopower and giant magnetothermopower with magnetic and structural heterogeneity in Sm0.55Sr0.45MnO3 manganite

    Science.gov (United States)

    Koroleva, L. I.; Morozov, A. S.; Jakhina, E. S.; Balbashov, A. M.

    2015-12-01

    It was first shown that the thermoelectric power in a magnetic semiconductor Sm0.55Sr0.45MnO3 is caused by ferromagnetic (FM) ferron-type nanoclusters and antiferromagnetic (AFM) CE-type nanoclusters with charge-orbital (CO) ordering. The presence of these clusters is caused by heavily Sr doping of a SmMnO3 compound, which replaced Sm ions. Thermoelectric power S and magnetothermopower ΔS/S has been studied in three samples: ceramics and two single-crystal samples. One of single-crystals was cooled in the air, another one was cooled in an oxygen atmosphere. The annealing in oxygen closes oxygen vacancies and, thus, increases the fraction of the CE-type AFM phase with the CO ordering which displaces the oxygen ions. S(T) curves of single-crystal sample cooled in the air and ceramic sample have a sharp increase starting from Curie temperature (TC) region and a slow decline till 325 K. At the same time {ΔS/S}(T) curves have a sharp minimum near TC=126 K, reaching the giant absolute value of 87% in the magnetic field H=14.17 kOe. This means that thermopower almost vanish with thermal destruction of FM clusters, i.e. thermopower is caused by these clusters in which crystal lattice is compressed. Oxygen cooled single-crystal's S(T) curves have a broad maximum near 270 K, including Neel temperature of CE-type clusters TNCE=240 K. {ΔS/S}(T) curve has a sharp minimum at the TNCE reaching the absolute value of 50% in H=13.2 kOe. The decrease of S is caused by destruction of CO order displacing oxygen ions in CE-type AFM clusters. Thus changed crystal lattice in nanoclusters of ferron type or AFM of CE-type makes the main contribution in thermopower in these three samples.

  5. Temperature and host dependence of the transition interference between f–f and f–d transitions of Sm{sup 2+} in matlockites

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Prodipta, E-mail: prodipta.pal08@gmail.com [Département de Chimie Physique,Sciences II, Université de Genève, 30, Quai Ernest-Ansermet, CH-1211 Genève 4 (Switzerland); Hagemann, Hans; Bill, Hans [Département de Chimie Physique,Sciences II, Université de Genève, 30, Quai Ernest-Ansermet, CH-1211 Genève 4 (Switzerland); Zhang, Jiahua [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033 (China)

    2015-05-15

    The absorption spectra of Sm{sup 2+} doped in MFX (M=Sr, Ba; X=Cl, Br) crystals were studied within the range of 20,000–35,000 cm{sup −1} as a function of temperature and host. The absorption bands observed were described with a simple model developed by Wood and Kaiser using group theory. The temperature and host dependence on the {sup 7}F{sub 0}→{sup 5}D{sub 3} Fano resonance lines were investigated. BaFCl:Sm{sup 2+} system showed a “normal” {sup 7}F{sub 0}→{sup 5}D{sub 3} transition at 4 K in spite of similar crystal structure and absorption profile with other MFX hosts. New Fano resonances were observed in the absorption spectra at higher energies (23,000–25,000 cm{sup −1}) for all MFX:Sm{sup 2+} systems at 4 K which persist up to room temperature. Preliminary energy level calculation showed that these resonance lines involve the interaction between higher excited {sup 5}L{sub J} states of 4f{sup 6} configuration and 4f{sup 5}5d{sup 1} configuration. - Highlights: • The absorption spectra of Sm{sup 2+} doped in MFX (M=Sr, Ba; X=Cl, Br) crystals within the range of as a function of temperature and host. • The absorption bands described with a simple model developed by Wood and Kaiser using group theory. • BaFCl:Sm{sup 2+} system showed a “normal” {sup 7}F{sub 0}→{sup 5}D{sub 3} transition at 4 K in spite of similar crystal structure and absorption profile with other MFX hosts. • New Fano resonances observed in the absorption spectra at higher energies (23,000–25,000 cm{sup −1}) for all MFX:Sm{sup 2+} systems at 4 K which persist up to room temperature.

  6. Fast timing study of a CeBr3 crystal: Time resolution below 120 ps at 60Co energies

    Science.gov (United States)

    Fraile, L. M.; Mach, H.; Vedia, V.; Olaizola, B.; Paziy, V.; Picado, E.; Udías, J. M.

    2013-02-01

    We report on the time response of a novel inorganic scintillator, CeBr3. The measurements were performed using a cylindrical crystal of 1-in. in height and 1-in. in diameter at 22Na and 60Co photon energies. The time response was measured against a fast reference BaF2 detector. Hamamatsu R9779 and Photonis XP20D0 fast photomultipliers (PMTs) were used. The PMT bias voltages and Constant Fraction Discriminator settings were optimized with respect to the timing resolution. The Full Width at Half Maximum (FWHM) time resolution for an individual CeBr3 crystal coupled to Hamamatsu PMT is found here to be as low as 119 ps at 60Co energies, which is comparable to the resolution of 107 ps reported for LaBr3(Ce). For 511 keV photons the measured FWHM time resolution for CeBr3 coupled to the Hamamatsu PMT is 164 ps.

  7. Fast timing study of a CeBr3 crystal: Time resolution below 120 ps at 60Co energies

    International Nuclear Information System (INIS)

    We report on the time response of a novel inorganic scintillator, CeBr3. The measurements were performed using a cylindrical crystal of 1-in. in height and 1-in. in diameter at 22Na and 60Co photon energies. The time response was measured against a fast reference BaF2 detector. Hamamatsu R9779 and Photonis XP20D0 fast photomultipliers (PMTs) were used. The PMT bias voltages and Constant Fraction Discriminator settings were optimized with respect to the timing resolution. The Full Width at Half Maximum (FWHM) time resolution for an individual CeBr3 crystal coupled to Hamamatsu PMT is found here to be as low as 119 ps at 60Co energies, which is comparable to the resolution of 107 ps reported for LaBr3(Ce). For 511 keV photons the measured FWHM time resolution for CeBr3 coupled to the Hamamatsu PMT is 164 ps.

  8. Sm{sup 3+}-doped alkaline earth borate glasses as UV→visible photon conversion layer for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Shen, L.F. [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Chen, B.J.; Pun, E.Y.B. [Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Lin, H., E-mail: lhai8686@yahoo.com [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2015-04-15

    Intense multi-peak red fluorescence emissions of Sm{sup 3+} are exhibited in alkaline-earth borate (LKZBSB) glasses under UV radiation. The spontaneous emission probabilities A{sub rad} corresponding to the {sup 4}G{sub 5/2}→{sup 6}H{sub J} (J=5/2, 7/2, 9/2 and 11/2) transitions are derived to be 24.74, 129.72, 117.03 and 32.23 s{sup −1}, respectively, and the relevant stimulated emission cross-sections σ{sub em} are 0.77×10{sup −22}, 4.46×10{sup −22}, 5.05×10{sup −22} and 1.38×10{sup −22} cm{sup 2}, confirming the effectiveness of red luminescence in Sm{sup 3+}-doped LKZBSB glasses. Quantitative characterization through the evaluation of absolute spectral parameters reveals that the quantum yield of Sm{sup 3+}-doped LKZBSB glasses is as high as 13.29%. Furthermore, with the introduction of Ce{sup 3+}, the effective excitation wavelength range and the emission intensity of Sm{sup 3+} in LKZBSB glasses are remarkably expanded and improved by a maximum sensitization factor of 9.02 in the UVB region. These results demonstrate that the present glass system has promising potential as an efficient UV→visible photon conversion layer for the enhancement of solar cell efficiency, including appealing applications in outer space. - Highlights: • Intense multi-peak red fluorescence emissions of Sm{sup 3+} are exhibited under UV radiation. • Effectiveness of red luminescence is confirmed by stimulated emission cross-sections. • Quantum yield of Sm{sup 3+}-doped LKZBSB glasses is 13.29% by quantitative characterization. • Effective excitation wavelength range and emission intensity are improved with Ce{sup 3+} doping. • Alkaline-earth borate glass has potential as solar cell UV→Vis photon conversion layer.

  9. ELECTROCHEMICAL BEHAVIOR AND KINETICS OF THE INTERVALENCE CHARGE TRANSFER FOR THE SM(III)/SM(II) REDOX COUPLE IN LiF-CaF2 MELT

    OpenAIRE

    Stulov Yuriy Vyacheslavovich; Korenko Michal; Kubikova Blanca; Kuznetsov Sergey Aleksandrovich

    2015-01-01

    This article is focused on the electrochemical investigation (cyclic voltammetry) of the redox couple Sm(III)/Sm(II) in an eutectic LiF–CaF2 melt containing SmF3. The first step of reduction for Sm(III) ions, involving one electron exchange in soluble/soluble Sm(III)/Sm(II) system, was found on a tungsten electrode. The study of the Sm(II)/Sm(0) electrode reaction was not feasible, since it’s the redox potential is in the same range of the solvent decomposition. The first step was fo...

  10. Orange and reddish-orange light emitting phosphors: Sm3+ and Sm3+/Eu3+ doped zinc phosphate glasses

    International Nuclear Information System (INIS)

    A spectroscopy study of Sm3+ and Sm3+/Eu3+ doped zinc phosphate glasses is performed through photoluminescence spectra and decay time profile measurements. Under Sm3+ excitation at 344 nm, the Sm3+ singly doped glass shows an orange global emission with x=0.579 and y=0.414 CIE1931 chromaticity coordinates, whereas the Sm3+/Eu3+ co-doped sample exhibits orange overall emissions (x=0.581 and y=0.398, and x=0.595 and y=0.387) and reddish-orange overall emission (x=0.634 and y=0.355) upon excitations at 344, 360 and 393 nm, respectively. Such luminescence from the co-doped sample is originated by the simultaneous emission of Sm3+ and Eu3+. Under Sm3+ excitation at 344 and 360 nm, the Eu3+ emission is sensitized and enhanced by Sm3+ through a non-radiative energy transfer process. The non-radiative nature was inferred from the shortening of the Sm3+ lifetime observed in the Sm3+/Eu3+ co-doped sample. An analysis of the Sm3+ emission decay time profiles using the Inokuti–Hirayama model suggests that an electric quadrupole–quadrupole interaction into Sm–Eu clusters might dominate the energy transfer process, with an efficiency of 0.17. - Highlights: • Zinc phosphate glasses are optically activated with Sm3+/Eu3+ (ZPOSmEu). • Non-radiative energy transfer Sm3+→Eu3+ takes place in ZPOSmEu. • ZPOSmEu overall emission can be modulated with the excitation wavelength. • ZPOSmEu might be useful as orange/reddish-orange phosphor for UV-white LEDs

  11. Band-overlap metallization of BaS, BaSe and BaTe

    Science.gov (United States)

    Carlsson, A. E.; Wilkins, J. W.

    1983-01-01

    The insulator-metal transition volumes for BaS, BaSe, and BaTe are calculated for the first time, using the self-consistent augmented spherical wave technique. The metallized transition volumes are smaller than those corresponding to the NaCl yields CsCl structural transitions, but, 10 to 15% larger than those obtained by the Herzfeld dielectric theory. The calculated equilibrium energy gaps in the NaCl structure underestimate the measured ones by 50 to 60%.

  12. Preparation of bone tumor therapeutic radiopharmaceuticals 153Sm-EDTMP

    International Nuclear Information System (INIS)

    Samarium-153-EDTMP (ethylene diamine tetramethylene phosphonate), for its promising biological properties, has been proved as a palliating therapeutic agent for bone tumor in human beings. 153Sm with high radionuclear purity and specific activity of 5.18 GBq (140 mCi)/mg Sm2O3 was prepared by irradiating natural Sm2O3(152Sm, 26.7%) sample, replacing costly enriched samarium oxide target, at a flux of 4 x 1013 n·cm-2·s-1 for 110 h. The yield of 153Sm complexing with EDTMP is greater than 98% at pH 8∼10 in boiling water bath for 30 min, and not significantly decreases within one week after 153Sm-EDTMP complex formation

  13. Synthesis and characterization of (Ba,Yb doped ceria nanopowders

    Directory of Open Access Journals (Sweden)

    Branko Matović

    2011-06-01

    Full Text Available Nanometric size (Ba, Yb doped ceria powders with fluorite-type structure were obtained by applying selfpropagating room temperature methods. Tailored composition was: Ce0.95−xBa0.05YbxO2−δ with fixed amount of Ba − 0.05 and varying Yb content “x” from 0.05 to 0.2. Powder properties such as crystallite and particle size and lattice parameters have been studied. Röntgen diffraction analyses (XRD were used to characterize the samples at room temperature. Also, high temperature treatment (up to 1550°C was used to follow stability of solid solutions. The mean diameters of the nanocrystals are determined from the full width at half maxima (FWHM of the XRD peaks. It was found that average diameter of crystallites is less than 3 nm. WilliamsonHall plots were used to separate the effect of the size and strain in the nanocrystals.

  14. BaP (PAH) air quality modelling exercise over Zaragoza (Spain) using an adapted version of WRF-CMAQ model

    International Nuclear Information System (INIS)

    Benzo(a)pyrene (BaP) is one of the most dangerous PAH due to its high carcinogenic and mutagenic character. Because of this reason, the Directive 2004/107/CE of the European Union establishes a target value of 1 ng/m3 of BaP in the atmosphere. In this paper, the main aim is to estimate the BaP concentrations in the atmosphere by using last generation of air quality dispersion models with the inclusion of the transport, scavenging and deposition processes for the BaP. The degradation of the particulated BaP by the ozone has been considered. The aerosol–gas partitioning phenomenon in the atmosphere is modelled taking into a count that the concentrations in the gas and the aerosol phases. If the pre-existing organic aerosol concentrations are zero gas/particle equilibrium is established. The model has been validated at local scale with data from a sampling campaign carried out in the area of Zaragoza (Spain) during 12 weeks. -- Highlights: • We have modelled transport, scavenging and deposition processes for BaP. • BaP Aerosol–gas partitioning phenomenon has been considered. • Degradation of BaP by the Ozone has been taken into account. • The new model has been validated using data from a PAH field campaign. -- BAP air quality modelling exercise using state-of-the-art air quality models and compare with BAP monitoring data in ad-hoc monitoring campaign

  15. Ternary borides with CeNi12B6 type structure

    International Nuclear Information System (INIS)

    The well-known LnNi12B6 and ∼ LnNi12B7 (Ln-Y, La, Pr, Nd, Sm, Gd) and prepared for the first time LnNi12B6(Ln-Tb, Dy) borides are proved to possess the rhombic structure of CeNi12B6 type. The parameters of the elementary cells for all compounds are determined. Continuous change in the parameters points to the three-valent state of rare earth atoms

  16. Flux pinning properties of TFA-MOD (Y,Gd)Ba2Cu3Ox tapes with BaZrO3 nanoparticles

    International Nuclear Information System (INIS)

    A high critical current density Jc with a nearly isotropic angular dependence at 77.3 K was recently obtained by the introduction of nanoparticles to (Y,RE)Ba2Cu3Oy (RE123, RE = Sm, Gd)-coated conductors prepared by trifluoroacetate metal-organic deposition (TFA-MOD). The flux pinning properties were evaluated on the basis of detailed measurements of the upper critical field, the irreversibility field and the critical current density of the TFA-MOD RE123-coated conductor. We found that strong random pinning by the BaZrO3 nanoparticles and weak c-axis correlated pinning by twin boundaries functioned cooperatively in nanoparticles introduced to (Y, Gd)123-coated conductors prepared by TFA-MOD. The coexistence of two different pinning centers played an important role in the nearly isotropic angular dependence of Jc.

  17. Dislocations in SmS single crystals

    International Nuclear Information System (INIS)

    Single crystals of SmS with NaCl structure are grown by zone melting in a sealed molybdenum tube. Dislocations introduced during cleaving the crystal are investigated by transmission electron microscopy. The dislocations have Burgers vector of 1/2 and their glide plane is (11-bar0), i.e. the slip system is (11-bar0) as in alkali-halide NaCl-type crystals. The slip seems to be governed by the Peierls mechanism for the screw dislocation. (author)

  18. Samlokalisering av småbedrifter

    OpenAIRE

    Myhre, Christi Wigenstad

    2012-01-01

    Alle bedrifter, uavhengig av størrelse, har sine oppgaver som må løses, både kjernefaglige og administrative. Imidlertid har ikke små bedrifter samme mulighet til spesialiseringer innen ulike fagfelt, slik som store bedrifter. I de minste bedriftene er det gjerne den som eier og driver bedriften som tar seg av alle oppgaver. For at en virksomhet skal være så konkurransedyktig og effektiv som mulig, er det viktig å utnytte bedriftens kjernekompetanse optimalt, og da kan det være hensi...

  19. A IBM study of quasibands in 166Sm

    International Nuclear Information System (INIS)

    The interacting boson model-1 (IBM-1) of Arima and Iachello has been successful in describing the collective nuclear properties in the medium mass nuclei. Earlier systematic studies of 146-154Sm have been performed using interacting boson model and Dynamic Pairing-Plus-Quadrupole (DPPQ) Model. Very recently Diab presented electrical monopole transition structure of 150Sm isotope. Simpson et al. successfully interpreted the isomers of 156-166Sm using Quasiparticle Rotor Model

  20. Thermal properties of perovskite RCeO{sub 3} (R = Ba, Sr)

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Aarti, E-mail: aarti.phy@gmail.com [Department of Physics, Barkatullah University, Bhopal 462026 (India); Parey, Vanshree; Thakur, Rasna [Department of Physics, Barkatullah University, Bhopal 462026 (India); Srivastava, Archana [Department of Physics, Sri Sathya Sai College for women, Bhopal 462024 (India); Gaur, N.K. [Department of Physics, Barkatullah University, Bhopal 462026 (India)

    2015-08-20

    Highlights: • (Ba,Sr)CeO{sub 3} are high temperature protonic conductor materials. • This makes their thermal properties very interesting. • MRIM has successfully predicted the thermodynamic properties. • The computed results are in good agreement with the available experimental data. • Present results will serve as guide to experimental workers in future. - Abstract: We have investigated the bulk modulus and thermal properties of proton conducting perovskite RCeO{sub 3} (R = Ba, Sr) for the first time by incorporating the effect of lattice distortion in modified rigid ion models (MRIM). The computed bulk modulus, specific heat, thermal expansion coefficient and other thermal properties of BaCeO{sub 3} and SrCeO{sub 3} reproduce well with the available experimental data. In addition the cohesive energy (ϕ), molecular force constant (f), reststrahlen frequency (ν), Debye temperature (θ{sub D}) and Gruneisen parameter (γ) are also reported and discussed. The specific heat results can further be improved by taking into account the spin and the orbital ordering contribution in the specific heat formulae.

  1. Disequilibrium effects in metal speciation by capillary electrophoresis inductively coupled plasma mass spectrometry (CE-ICP-MS); theory, simulations and experiments.

    Science.gov (United States)

    Sonke, Jeroen E; Salters, Vincent J M

    2004-08-01

    A theoretical-experimental approach to evaluate disequilibrium effects in capillary electrophoresis inductively coupled plasma mass spectrometry (CE-ICP-MS) is presented. Electrophoresis requires metal ligand (ML) complexes to be stable on the time scale of separation and detection. By expressing ML complex stability in terms of half-life during a CE separation, an evaluation of separation artifacts can be made. Kinetically slow metals like Cr, Al or Fe form complexes that are stable on the time scale of electrophoretic separations. Kinetically fast metals, like Pb, Hg, Cu, Cd and REE, however tend to form labile complexes which unless complexed by strong chelators will dissociate during CE separations. A reactive transport simulation model of CE separations involving ML complexes allows a more detailed prediction of disequilibrium bias and identifies kinetically limited from mobility-limited types of dissociation. Complementary experimental results are given for kinetic and equilibrium binding experiments of Sm with humic acid. The equilibrium logK for Sm-Leonardite humic acid (HA) binding at pH 7 and 0.01 mol L(-1) ionic strength was determined to be 13.04. Kinetic rates of formation and dissociation for SmHA were 5.9 10(8) and 5.3 10(-5) mol s(-1). PMID:15284917

  2. CHRiSM: CHance Rules induce Statistical Models

    OpenAIRE

    Sneyers, Jon; Meert, Wannes; Vennekens, Joost

    2009-01-01

    A new probabilistic-logic formalism, called CHRiSM, is introduced. CHRiSM is based on a combination of CHR and PRISM. It can be used for high-level rapid prototyping of complex statistical models by means of chance rules. The underlying PRISM system can then be used for several probabilistic inference tasks, including parameter learning. We describe a source-to-source transformation from CHRiSM rules to PRISM, via CHR(PRISM). Finally we discuss the relation between CHRiSM and probab...

  3. Vliv stabilizátorů a dalších složek na výslednou kvalitu sypkých směsí pro výrobu zmrzlin

    OpenAIRE

    Sládková, Veronika

    2011-01-01

    Předložená diplomová práce byla zaměřena na studium vlivu stabilizátorů a dalších složek na výslednou kvalitu sypkých směsí pro výrobu zmrzlin. Diplomová práce byla řešena ve spolupráci s výrobcem směsí Frujo, a.s., Tvrdonice, a to za účelem výběru vhodného stabilizátoru pozitivně ovlivňujícího výslednou kvalitu výrobku. V rámci experimentální práce bylo analyzováno šest stabilizačních směsí, tři kompletní sypké směsi pro výrobu točených zmrzlin a jednotlivé suroviny pro výrobu těchto sypkých...

  4. Sm@C1(153491)-C94: A missing isomer from Sm@C94 mono-metallofullerenes

    Science.gov (United States)

    Zhao, Pei; Guo, Yi-Jun; Zhao, Rui-Sheng; Zhao, Xiang

    2016-01-01

    The Sm-containing endohedral metallofullerene (EMF) Sm@C94 has been investigated by quantum chemical and statistical thermodynamic methods. Sm@C1(153491)-C94 and Sm@C3v(153493)-C94 which both satisfy the isolated-pentagon rule (IPR) are exposed to possess considerable thermodynamic stabilities within the fullerene-formation temperature region (500-3000 K). Sm@C3v(153493)-C94 has been indeed determined experimentally, and a novel structure, Sm@C1(153491)-C94, is reported for the first time. These two isomers are related by a single Stone-Wales transformation. Meanwhile, frontier molecular orbital, natural electron configuration, and Mayer bond order analyses were employed to uncover their electronic properties. In addition, their optical spectra were simulated to support experimental identification and characterization.

  5. Collective excitations in 132Ce

    International Nuclear Information System (INIS)

    The structure of normally deformed states (β2∼0.2) in 132Ce has been investigated using EUROGAM2. Eight ΔI=2 bands and three ΔI=1 bands have been identified up to spin 40. The results are interpreted with the aid of Woods-Saxon cranking calculations which suggest a variety of triaxial shapes stabilized by specific active quasiparticle orbitals. (authors)

  6. The SmS-Ga2S3 section of the ternary Sm-Ga-S system

    International Nuclear Information System (INIS)

    The SmS-Ga2S3 section of the Sm-Ga-S system is investigated by differential-thermal, XPA, and microstructural analyses and changes in the microhardness. The XPA was performed with a DRON-2 diffractometer using CuK /SUB a/ radiation. Microstructural analysis showed that alloys containing 0-2, 33.3, and 50 mole % SmS were single-phase and the rest were two-phase

  7. Cross-section SmS-Ga2S3 of Sm-Ga-S ternary system

    International Nuclear Information System (INIS)

    The SmS-Ga2S3 system state diagram has been built up for the first time on the basis of the data of differential thermal, microstructural, and X-ray phase analyses and also according to the results of microhardness measurements. It has been established that ternary SmGa2S4, SmGa4S7 compounds are formed in the system

  8. Invisible KL decays in the SM extensions

    Science.gov (United States)

    Gninenko, S. N.; Krasnikov, N. V.

    2016-07-01

    In the Standard Model (SM), the branching ratio for the decay KL → νν¯ is helicity suppressed and predicted to be very small ≤ O(10‑17). We consider two natural extensions of the SM as the two-Higgs-doublet model (2HDM) and the neutrino minimal Standard Model (νMSM) with additional singlet scalar, whose main feature is that they can lead to an enhanced Br(KL → invisible). In the 2HDM, the smallness of the neutrino mass is explained due to the smallness of the second Higgs doublet vacuum expectation value. Moreover, the νMSM extension with additional singlet field can explain the (g ‑ 2)μ anomaly. The considered models demonstrate that the KL → invisible decay is a clean probe of new physics scale well above 100 TeV, that is complementary to rare K → π + invisible decay, and provide a strong motivation for its sensitive search in a near future low-energy experiment.

  9. Photoluminescence characteristics of reddish-orange Eu{sup 3+} or Sm{sup 3+} singly-doped and Eu{sup 3+} and Sm{sup 3+} co-doped KZnGd(PO{sub 4}){sub 2} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jun Ho; Bandi, Vengala Rao; Grandhe, Bhaskar Kumar; Jang, Ki Wan; Lee, Ho Sueb [Changwon National University, Changwon (Korea, Republic of); Yi, Soung Soo [Silla University, Busan (Korea, Republic of); Jeong, Jung Hyun [Pukyong National University, Busan (Korea, Republic of)

    2011-02-15

    Eu{sup 3+} or Sm{sup 3+} singly-doped and Eu{sup 3+} and Sm{sup 3+} co-doped KZnGd(PO{sub 4}){sub 2} phosphors were synthesized by using a conventional solid state reaction method at 750 .deg. C. The emission spectra of KZnGd{sub 1-x}(PO{sub 4}){sub 2}:Eu{sup 3+}{sub x} with {lambda}{sub ex} = 395 nm and KZnGd{sub 1-y}(PO{sub 4}){sub 2}:Sm{sup 3+}{sub y} with {lambda}{sub ex} = 403 nm phosphors showed intense {sup 5}D{sub 0} {yields} {sup 7}F{sub 1}, {sup 4}G{sub 5/2} {yields} {sup 6}H{sub 7/2} emission transitions at 595 nm and 599 nm, respectively. The optimum relative intensity of the KZnGd{sub 1-x-y}(PO{sub 4}){sub 2}:Eu{sup 3+}{sub x} , Sm{sup 3+}{sub y} phosphor was obtained for the doping concentrations of (x = 0.09, y = 0.01). In addition, the temperature dependent luminescence intensity of the synthesized phosphors was investigated and the thermal stability of the KZnGd(PO{sub 4}){sub 2}:Eu{sup 3+} phosphor was found to be higher than that of standard YAG:Ce{sup 3+} and KZnGd{sub 1-x-y}(PO{sub 4}){sub 2}:Eu{sup 3+}{sub x} Sm{sup 3+}{sub y} under near ultra-violet (NUV) light emitting diode excitation (LED). Therefore, we suggest that Eu{sup 3+} or Sm{sup 3+} singly-doped and Eu{sup 3+} and Sm{sup 3+} co-doped KZnGd(PO{sub 4}){sub 2} phosphors should be efficient for different red-color-emitting display device applications and NUV-LED-based white-light-emitting diodes.

  10. Immunocapture of circulating Schistosoma mansoni cathepsin B antigen (Sm31) by anti-Sm31 polyclonal antibodies.

    Science.gov (United States)

    González, Amelia Y; Sulbarán, Guidenn S; Ballen, Diana E; Cesari, Italo M

    2016-06-01

    Adult Schistosoma mansoni parasites have the capacity to degrade ingested host hemoglobin and other host plasma proteins by using a series of gut proteolytic enzymes, including cathepsin B; this enzyme is released to the host intravascular environment during regurgitations of adult worms. Cathepsin B becomes thus a circulating parasite component that has been shown to be specifically recognized as the Sm31 antigen by antibodies present in most S. mansoni infected patients. Taking advantage of this immunological property, we attempted here to immunocapture Sm31 from sera of infected patients using specific polyclonal rabbit antibodies raised against a highly enriched preparation of Sm31 and detect its intrinsic proteolytic activity using a previously described solid-phase procedure called Cysteine Protease Immuno Assay (CPIA). To produce highly specific anti-Sm31/cathepsin B antibodies, cathepsin B (Sm31 or SmCB) was enriched more than 3000-folds from an adult worm preparation using a series of conventional biochemical steps including ion exchange and affinity chromatography. Anti-cathepsin B antibodies were generated by immunizing rabbits with the enriched cathepsin B fraction; these antibodies recognized a band of Mr.~31kDa in Western-blot (WB) analysis of this fraction and were able to capture, in a modified CPIA procedure, Sm31/SmCB present in sera from infected Venezuelan patients living in low endemic areas for schistosomiasis. CPIA showed 100% sensitivity and 100% specificity; representing a new diagnostic tool to detect circulating Sm31 antigen in actual infections. PMID:26709076

  11. Identification of levels in neutron-rich 145Ce and 147Ce nuclei

    International Nuclear Information System (INIS)

    High-spin structures in the neutron-rich nuclei 145Ce and 147Ce produced in the spontaneous fission of 252Cf have been investigated by prompt γ-ray spectroscopy. A collective band structure in 145Ce is identified. Several sidebands along with the new high-spin states in 147Ce are also identified. Particle-plus-rotor model calculations indicate that the yrast bands in 145Ce and 147Ce most probably originate from coupling of the νi13/2 orbital to the ground states of 144Ce and 146Ce. The ground state configurations of 145,147Ce are (νh9/2+νf7/2) and νh9/2, respectively. (c) 1999 The American Physical Society

  12. Energy levels of the Ce activator relative to the YAP(Ce) scintillator host

    International Nuclear Information System (INIS)

    The electronic structure of the cerium-activated yttrium aluminum perovskite [YAP(Ce)] scintillator has been studied by core level x-ray spectroscopy and first-principles calculations. X-ray absorption and emission spectra at the oxygen K-edge of YAP(Ce) and CeO2 have been measured and compared with the calculated partial density of states. With the known band gap of CeO2, the measured oxygen K-edge absorption and emission spectra are used to construct a fixed relation between the valence and conduction bands of YAP and CeO2. This allows us to determine the fundamental band gap of YAP to be 8.1 ± 0.3 eV. A comparison between the cerium M4,5-edges x-ray absorption spectra of the YAP(Ce) and Ce model compounds (CeO2, CeF3, and Ce foils) then shows that the Ce activator is in the desired Ce3+, with a small fraction of Ce4+ due to oxidization at the surface. Finally, we determine that the ground state 4f1 energy level of the Ce3+ activator lies 1.8 ± 0.5 eV above the top of the valence band of the host YAP. (paper)

  13. Småbørn i interaktion

    DEFF Research Database (Denmark)

    Fisker, Tine Basse

    Småbørn i interaktion. En undersøgelse af socialt udviklingspotentiale og muligheder for interaktion for småbørn med autisme i forskellige pædagogiske og organisatoriske miljøer. På baggrund af kvalitativ, naturalistisk empiri, i form af observationer, videooptagelser, interviews og samtaler, søg...

  14. Chemical study on the labeling of EDTB with 153Sm

    International Nuclear Information System (INIS)

    Objective: According to conjugation characteristic of N, N, N', N'-tetrakis (2-benzymidazolylmethyl)-1, 2-ethanediamine (EDTB) with lipiodol selectively retained within hepatic tumors, in this paper, the labeling of EDTB with therapeutic nuclide 153Sm was first systematically studied by different labeling pathways, to further develop new labeled compounds with 153Sm for the treatment of hepatocellular carcinoma. Methods: A radio-paper chromatography (RPC) was used to determine the purity of the labeled compound with the mixture of pyridine: ethanol: water (1:2:4, V/V) as developer. Using independence variable method, the effect of labeling conditions, such as reaction time, temperature and concentration of EDTB on labeling yield were investigated, and the in vitro stability of 153Sm-EDTB was also demonstrated by RPC. Results: the RPC analysis indicated that Rf value of free 153Sm or 153Sm-EDTB was 0.0-0.1 and 0.6-0.7, respectively. Using acetic acid as reaction medium, in an open nitrogen-pouring labeling system, heated in boiling water bath for not less than 30 min, the labeling yield of 153Sm-EDTB was more than 97% and could remain in 24 hours after preparing the labeled compound at room temperature. Conclusion: The optimum labeling method and conditions were achieved. The in vitro stability of 153Sm-EDTB was good; thereby this provided possibility for further preparation and biological research of potential therapeutic radiopharmaceutical labeled lipiodol with 153Sm via EDTB for liver cancer

  15. Isotope shift measurement of autoionization Rydberg states of Sm

    International Nuclear Information System (INIS)

    The observation and measurement of isotope shift of autoionization Rydberg states 8G1/2 of Sm was reported. The isotope shift of the first excited state of Sm was also measured. Results were compared with that in Ref. 5

  16. Isotope shift measurement of autoionization Rydberg states of Sm

    International Nuclear Information System (INIS)

    The observation and measurement of isotope shift of autoionization Rydberg states 8G1/2 of Sm was reported. The isotope shift of the first excited state of Sm was also measured. Results were compared with that in Ref. 5. copyright 1997 American Institute of Physics

  17. Symmetries for SM Alignment in multi-Higgs Doublet Models

    CERN Document Server

    Pilaftsis, Apostolos

    2016-01-01

    We derive the complete set of maximal symmetries for Standard Model (SM) alignment that may occur in the tree-level scalar potential of multi-Higgs Doublet Models, with $n > 2$ Higgs doublets. Our results generalize the symmetries of SM alignment, without decoupling of large mass scales or fine-tuning, previously obtained in the context of two-Higgs Doublet Models.

  18. Cross sections of deuteron induced reactions on $^{nat}$Sm for production of the therapeutic radionuclide $^{145}$Sm and $^{153}$Sm

    CERN Document Server

    Tárkányi, F; Takács, S; Ditrói, F; Csikai, J; Ignatyuk, A V

    2014-01-01

    At present, targeted radiotherapy (TR) is acknowledged to have great potential in oncology. A large list of interesting radionuclides is identified, including several radioisotopes of lanthanides, amongst them $^{145}$Sm and $^{153}$Sm. In this work the possibility of their production at a cyclotron was investigated using a deuteron beam and a samarium target. The excitation functions of the $^{nat}$Sm(d,x)$^{145153}$Sm reactions were determined for deuteron energies up to 50 MeV using the stacked-foil technique and high-resolution $\\gamma$-ray spectrometry. The measured cross sections and the contributing reactions were analyzed by comparison with results of the ALICE, EMPIRE and TALYS nuclear reaction codes. A short overview and comparison of possible production routes is given.

  19. Design of a novel optically stimulated luminescent dosimeter using alkaline earth sulfides doped with SrS:Eu,Sm materials

    Institute of Scientific and Technical Information of China (English)

    Yanping Liu; Zhaoyang Chen; Yanwei Fan; Weizhen Ba; Wu Lu; Qi Guo; Shilie Pan; Aimin Chang; Xinqiang Tang

    2008-01-01

    Optically stimulated luminescence (OSL) is the luminescence emitted from an irradiated insulator or semiconductor during exposure to light.The OSL intensity is a function of the dose of radiation absorbed by the sample and thus can be used as the basis of a radiation dosimetry method.Alkaline earth sulfides doped with rare-earth elements such as Ce,Sm and Eu are OSL dosimeters having very high sensitivity,and the OSL with a short time constant is separated from the stimulated light.In this paper,a novel OSL dosimeter designed with SrS:Eu,Sm materials is described.The dosimeter takes advantage of the characteristics of charge trapping materials SrS:Eu,Sm that exhibit OSL.The measuring range of the dosimeter is from 0.01 to 100Gy.The equipment,which is relatively simple and small in size,is promising for applications in space exploration and high dose radiation dosimetry.

  20. Metallic nanowires on SmSi interface

    Energy Technology Data Exchange (ETDEWEB)

    Duverger, E; Palmino, F; Labrune, J C [Institut FEMTO-ST Dpt CREST, CNRS UMR 6174, 4 place Tharradin, BP 71427, 25211 Montbeliard cedex (France)

    2007-03-15

    The manufacture of nanowires and the exploitation of their specific properties are the great fields of fundamental and industrial research. Some nanostructuration can be obtained with the help of conventional lithography technics; nevertheless these technics are limited by the optical resolution, the introduction of many defects and the residual damage related to engraving. A new approach, which consists to create nanowires in-situ on pre structured SmSi(111) interface has been investigated by scanning tunneling microscopy (STM). This interface is known to permit the creation of many different 1D templates in the submonolayer range. We show in this study, the possibility to create Fe nano-objects of well-defined size distributed in an ordered array.

  1. Micromagnetic Simulation of Magnetization Reversal in SmCo5/Sm2Co17 Magnets

    Institute of Scientific and Technical Information of China (English)

    荣传兵; 张宏伟; 杜晓波; 张健; 张绍英; 沈保根

    2004-01-01

    A three-dimensional finite element micromagnetic algorithm was developed to study the magnetization reversal of the SmCo5/Sm2Co17 based magnets. The influences of the microstructure and magnetic parameters on the coercivity were studied based on the model consisting of 64 irregular cells according to the experimental microstructure. Numerical results show that the coercivity increases with increasing the 2∶17-type cell size. Large cell boundary thickness leads to small coercivity. The drop of anisotropy constant of 1∶5 phase leads to the coercivity reducing, while the effect of exchange constant of 1∶5 phase on coercivity is contrary to that of exchange constant. The calculated field dependence of coercivity can be predicted by an inhomogeneous domain-wall pinning model. The microstructure parameter was analyzed by comparing the calculated coercivity.

  2. The decay of 120Ba

    International Nuclear Information System (INIS)

    120Ba was produced by bombarding a 2 mg/cm2 thick 106Cd target with a 68 MeV 16O beam and fluorated in a helium-jet ion source. The decay of on-line mass separated activity 120Ba has been studied by γ-X, γ-γ and γ-β coincidence measurements. Its half-life was measured to be 24 ± 2s. The total decay energy was extracted to be QEG 5.0 ± 0.3 MeV. A simple decay scheme has been proposed

  3. Phase equilibria in Sb2S3-SmS system

    International Nuclear Information System (INIS)

    Methods of physicochemical analysis is used to study Sb2S3-SmS cross section, which is a quasibinary one of Sm-Sb-S ternary system. Three new compounds: SmSb4S7, SmSb2S4 and Sm3Sb4S9 are formed in the system, the first one melts congruently, two others - incongruently. Solubility of Sb2S3 is 3 mol.% SmS at 300 K

  4. Optic phonon anomalies and f-d hybridization in SmS and SmB6

    International Nuclear Information System (INIS)

    The optic phonons of semiconducting SmS and of (homogeneously) mixed-valent SmS and SmB6 have been investigated by means of Raman scattering. The dominant electron-phonon interaction upon resonantly exciting the 4f shell is revealed as a coupling of the strongly localized 4f hole at the Sm site to full symmetric (Asub(1g)) displacements of the nearest neighbour anions, i.e. mainly to LO(L) phonons. Semiconducting and mixed-valent, metallic SmS show a 'softening' of the LO(L) phonon frequencies with respect to the other divalent and trivalent rare earth sulfides, respectively, going in parallel with a 'softening' of the bulk modulus. The f-d hybridization is considered as the common origin of these phonon frequency renormalizations. (author)

  5. 4f and 5d energy levels of the divalent and trivalent lanthanide ions in M{sub 2}Si{sub 5}N{sub 8} (M=Ca, Sr, Ba)

    Energy Technology Data Exchange (ETDEWEB)

    Kate, O.M. ten, E-mail: o.m.tenkate@tudelft.nl [Luminescent Materials Research Group, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands); Energy Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5600MB Eindhoven (Netherlands); Zhang, Z. [Energy Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5600MB Eindhoven (Netherlands); Dorenbos, P. [Luminescent Materials Research Group, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands); Hintzen, H.T. [Energy Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5600MB Eindhoven (Netherlands); Kolk, E. van der [Luminescent Materials Research Group, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands)

    2013-01-15

    Optical data of Sm, Tb and Yb doped Ca{sub 2}Si{sub 5}N{sub 8} and Sr{sub 2}Si{sub 5}N{sub 8} phosphors that have been prepared by solid-state synthesis, are presented. Together with luminescence data from literature on Ce{sup 3+} and Eu{sup 2+} doping in the M{sub 2}Si{sub 5}N{sub 8} (M=Ca, Sr, Ba) hosts, energy level schemes were constructed showing the energy of the 4f and 5d levels of all divalent and trivalent lanthanide ions relative to the valence and conduction band. The schemes were of great help in interpreting the optical data of the lanthanide doped phosphors and allow commenting on the valence stability of the ions, as well as the stability against thermal quenching of the Eu{sup 2+}d-f emission. Tb{sup 3+} substitutes on both a high energy and a low energy site in Ca{sub 2}Si{sub 5}N{sub 8}, due to which excitation at 4.77 eV led to emission from both the {sup 5}D{sub 3} and {sup 5}D{sub 4} levels, while excitation at 4.34 eV gave rise to mainly {sup 5}D{sub 4} emission. Doping with Sm resulted in typical Sm{sup 3+}f-f line absorption, as well as an absorption band around 4.1 eV in Ca{sub 2}Si{sub 5}N{sub 8} and 3.6 eV in Sr{sub 2}Si{sub 5}N{sub 8} that could be identified as the Sm{sup 3+} charge transfer band. Yb on the other hand was incorporated in both the divalent and the trivalent state in Ca{sub 2}Si{sub 5}N{sub 8}. - Graphical abstract: Energy level schemes showing the 4f ground states of the trivalent ( Black-Down-Pointing-Small-Triangle ) and divalent ( Black-Up-Pointing-Small-Triangle ) lanthanide ions and lowest energy 5d states of the trivalent ({nabla}) and divalent ({Delta}) ions with respect to the valence and conduction bands of Ca{sub 2}Si{sub 5}N{sub 8} (left) and Sr{sub 2}Si{sub 5}N{sub 8} (right). Highlights: Black-Right-Pointing-Pointer Construction of energy level schemes of all lanthanides within the M{sub 2}Si{sub 5}N{sub 8} hosts. Black-Right-Pointing-Pointer Construction was done by analyzing existing as well as new

  6. The effect of Pr co-dopant on the performance of solid oxide fuel cells with Sm-doped ceria electrolyte

    International Nuclear Information System (INIS)

    Samaria-doped ceria Ce0.9Sm0.1O1.95 (SDC) and samaria and praseodymium co-doped ceria Ce0.9Sm0.08Pr0.02O1.95 (SPDC) powders were synthesized by glycine nitrate process. SDC and SPDC electrolytes were made using the corresponding powders to press pellets and sinter them in air at 1400 deg. C. SEM and open porosity measurement showed the electrolytes were not dense and SPDC was more porous than SDC. Raman spectra indicated the oxygen vacancy concentration of SPDC was higher than SDC. Solid oxide fuel cells (SOFCs) with SPDC and SDC electrolytes were made and tested. The SOFC with SPDC electrolyte had higher power density but lower open circuit voltage. Impedance measurement was undertaken for the SOFCs at open circuit and the results showed that both the Ohmic and polarization resistances for SPDC electrolyte are smaller than for SDC. It is explained that co-doping Pr in Sm-doped ceria may increase the oxygen ionic conductivity by changing the grain boundary conditions so that more oxygen vacancies may exist and move faster. The electrochemical catalytic activity of Pr may play an important role in decreasing the polarization of electrolyte-electrode interface of the SOFCs

  7. Removal of NOx with Porous Cell Stacks with La0.85Sr0.15CoxMn1-xO3+δ-Ce0.9Gd0.1O1.95 Electrodes Infiltrated with BaO

    DEFF Research Database (Denmark)

    Werchmeister, Rebecka Maria Larsen; Bentzen, Janet Jonna; Andersen, Kjeld Bøhm; Kammer Hansen, Kent

    2014-01-01

    Porous cell stacks with composite electrodes of La0.85Sr0.15CoxMn1-xO3-Ce0.9Gd0.1O1.95 were tested for activity toward selective electrochemical reduction of NOx to N2 in the presence of 10% O2. The cell stacks were produced by tape casting, laminating and sintering the backbone structure followed...

  8. TRANSITIVITY AND THE BA CONSTRUCTION

    Directory of Open Access Journals (Sweden)

    Pei-Jung Kuo

    2010-06-01

    Full Text Available In this paper, I discuss the legitimacy of positing a Transitivity Projection (= TrP cf. Bowers 1993, 1997, 2001 and 2002 in the BA construction in Mandarin Chinese. BA has been proposed to be a semantically-bleached verb, inserted in the v position (Huang 1997 and Lin 2001. Several pieces of evidence such as manner adverbial placement (cf. Huang, Li and Li 2009 and GEI-insertion (cf. Tang 2001 indicate that there must be a functional projection between the vP and VP to host the BA NP. I propose that a TrP is probably the most apt candidate for the XP. I also argue, in contrast to the proposal by Huang, Li and Li (2009, that the present proposal which employs a TrP captures most of the properties of the BA construction. A comparison with the structure of the BEI construction also shows that the TrP proposal fits into the general picture of current linguistic theory on transitive constructions without extra stipulations.

  9. Thermal neutron capture cross sections for the 152Sm(n,γ) 153Sm and 154Sm(n,γ) 155Sm reactions at 0.0536 eV energy

    Science.gov (United States)

    Uddin, M. S.; Chowdhury, M. H.; Hossain, S. M.; Latif, Sk. A.; Islam, M. A.; Hafiz, M. A.; Mubin, S. H.; Zakaria, A. K. M.; Yunus, S. M.; Azharul Islam, S. M.

    2008-11-01

    The neutron capture cross sections for the 152Sm(n,γ) 153Sm and 154Sm(n,γ) 155Sm reactions at 0.0536 eV neutron energy were measured using an activation technique based on the TRIGA Mark-II research reactor, relative to the reference reaction 197Au(n,γ) 198Au. The activity was measured nondestructively using gamma-ray spectroscopy. Our measured values at this neutron energy are the first ones and are compared with 1/ v based evaluated cross sections reported in the ENDF/B-VII and JENDL-3.3 libraries. The measured value for the 152Sm(n,γ) 153Sm reaction is 0.28% lower than JENDL-3.3 and 0.48% higher than ENDF/B-VII. Our value for the production of 155Sm is about 3% and 2.3% higher than the evaluated value with ENDF/B-VII and JENDL-3.3 at 0.0536 eV, respectively.

  10. Phase formation in the BaB2O4-BaF2 system

    Science.gov (United States)

    Bekker, T. B.; Fedorov, P. P.; Kokh, A. E.

    2012-07-01

    It is shown that the BaB2O4-BaF2 system is quasi-binary with the following eutectics coordinates: 760°C, 59 mol % BaF2, 41 mol % BaB2O4. Due to the intense pyrohydrolysis during the growth of β-BaB2O4 crystals from the 55.6 mol % BaB2O4-44.4 mol % BaF2 composition, the Ba5B4O11 compound is formed in the system. This process leads to the cocrystallization of the β-BaB2O4 and Ba5B4O11 phases and impedes the formation of high-quality crystals.

  11. CeO2夹层在YSZ基SOFC中的研究进展%Research Progress on CeO2 Interlayer in YSZ-based SOFC

    Institute of Scientific and Technical Information of China (English)

    郝洪荣

    2009-01-01

    回顾了Y2O3、Sm2O3和Gd2O3掺杂的CeO2夹层(YDC、SDC和GDC)在Y2O3稳定的ZrO2(YSZ)基SOFC中的发展历史以及目前发展状况,分析了粉体的制备方法、夹层的沉积工艺、陶瓷烧结工艺对CeO2夹层性能的影响.从材料的化学相容性和热膨胀匹配等方面阐述了制备CeO2夹层的目的,对CeO2夹层大大提高电极性能进行了详尽的机理分析.指明了CeO2夹层对SOFC的重要作用和发展前景.

  12. Photoelectron spectra of CeO{sup −} and Ce(OH){sub 2}{sup −}

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Manisha; Felton, Jeremy A.; Kafader, Jared O.; Topolski, Josey E.; Jarrold, Caroline Chick, E-mail: cjarrold@indiana.edu [Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405 (United States)

    2015-02-14

    The photoelectron spectrum of CeO{sup −} exhibits what appears to be a single predominant electronic transition over an energy range in which numerous close-lying electronic states of CeO neutral are well known. The photoelectron spectrum of Ce(OH){sub 2}{sup −}, a molecule in which the Ce atom shares the same formal oxidation state as the Ce atom in CeO{sup −}, also exhibits what appears to be a single transition. From the spectra, the adiabatic electron affinities of CeO and Ce(OH){sub 2} are determined to be 0.936 ± 0.007 eV and 0.69 ± 0.03 eV, respectively. From the electron affinity of CeO, the CeO{sup −} bond dissociation energy was determined to be 7.7 eV, 0.5 eV lower than the neutral bond dissociation energy. The ground state orbital occupancies of both CeO{sup −} and Ce(OH){sub 2}{sup −} are calculated to have 4f 6s{sup 2} Ce{sup +} superconfigurations, with open-shell states having 4f5d6s superconfiguration predicted to be over 1 eV higher in energy. Low-intensity transitions observed at higher electron binding energies in the spectrum of CeO{sup −} are tentatively assigned to the {sup 1}Σ{sup +} (Ω = 0) state of CeO with the Ce{sup +2}⍰6s{sup 2} superconfiguration.

  13. Corrosion behavior of Co-Sm based magnetic media

    International Nuclear Information System (INIS)

    In this article the long term stability of Co-Sm thin films, both with no overcoat and covered with silicon nitride layers of varying thickness, has been investigated by means of accelerated corrosion tests in vacuum, air, and in a humidity chamber. Bare Co-Sm films exhibit an accelerated decrease in magnetization with respect to reference Co-Pt films, dependent in part on the effective surface area of the magnetic film. X-ray photoelectron spectroscopy depth profiling and corrosion tests demonstrate that silicon nitride layers of about 8 nm should provide adequate protection against degradation of the magnetic properties of Co-Sm thin films

  14. Physical properties of the R3Pt23Si11 compounds with volatile rare earth: Sm, Eu, Tm and Yb

    International Nuclear Information System (INIS)

    The new R3Pt23Si11 series, where R is a rare earth, has been completed with the synthesis of three new compounds with volatile rare earth: R=Eu, Sm, and Tm. The studies of their physical properties have been performed along with those of the Yb3Pt23Si11 compound. The X-ray powder diffraction patterns confirm that they all crystallize in the same face-centered cubic structure, space group Fm3¯m, as the rest of the series. The refinements of the diffraction patterns show an anomalously high lattice parameter in Eu3Pt23Si11 and Yb3Pt23Si11, indicating a divalent valence state for Eu and Yb. This 2+ valence state for Eu and Yb ions is confirmed by the magnetic measurements. A ferromagnetic order is observed at TC=5.54±0.07 K and 10.12±0.07 K in Eu3Pt23Si11 and Sm3Pt23Si11 respectively. In Tm3Pt23Si11 no magnetic order is found down to 0.36 K while Yb3Pt23Si11 reveals a diamagnetic behavior. At low temperatures the spontaneous moment, Ms, in Eu3Pt23Si11 is in agreement with a L=0, S=7/2 state for the Eu2+ ion. On the contrary in Sm3Pt23Si11, Ms is far below the 0.714μB expected for the saturated moment of the Sm3+ in the J=7/2 ground state multiplet. - Highlights: • R3Pt23Si11 with volatile rare earth Sm, Eu, Tm and Yb have been synthesized. • Structural studies confirm that they crystallize in the same structure as Ce3Pt23Si11. • For Eu- and Yb-3Pt23Si11 a divalent valence state is found for Eu and Yb. • Eu- and Sm-3Pt23Si11 present a ferromagnetic order at 5.54 K and 10.12 K respectively. • In Tm3Pt23Si11 no magnetic order is found down to 0.36 K, Yb3Pt23Si11 is diamagnetic

  15. Readout of a LaBr 3:Ce continuous crystal by a MPPC array: First results

    Science.gov (United States)

    Scafè, R.; Cinti, M. N.; Di Lorenzo, P.; Zambotti, A.; Sacco, D.; Pisacane, F.; Bennati, P.; Miscioscia, R.; Pellegrini, R.; Pani, R.

    2009-07-01

    In this work preliminary results of single-photon measurements made with a LaBr3:Ce continuous scintillation crystal (BrilLanCe 380™, by Saint-Gobain Crystals, FR) coupled to an array of Multi-Pixel Photon Counters (MPPC™, by Hamamatsu Photonics, JP) are presented. The array of 7 MPPCs was realized as the innermost element of the hexagonal Anger-like structure suitable for growing to larger areas by adding peripheral elements. The design of MPPC electronic readout for position determination was based on Anger logic. Wide-band amplifiers (by MITEQ®, US) were used for signals conditioning. Digitized traces of background, 57Co and 133Ba collimated irradiation were captured, characterized and stored by using the data-logging capabilities of a WaveMaster Oscilloscope (by LeCroy, US). Results are presented in terms of energy response, position sensing and signals fall and rise times.

  16. Synthesis, crystal structure, and magnetism of A2Co12As7 (A=Ca, Y, Ce-Yb)

    Science.gov (United States)

    Tan, Xiaoyan; Ovidiu Garlea, V.; Chai, Ping; Geondzhian, Andrey Y.; Yaroslavtsev, Alexander A.; Xin, Yan; Menushenkov, Alexey P.; Chernikov, Roman V.; Shatruk, Michael

    2016-04-01

    Ternary intermetallics, A2Co12As7 (A=Ca, Y, Ce-Yb), have been synthesized by annealing mixtures of elements in molten Bi at 1223 K. The materials obtained crystallize in the P63/m variant of the Zr2Fe12P7 structure type. The unit cell volume shows a monotonic decrease with the increasing atomic number of the rare-earth metal, with the exception of Ce-, Eu-, and Yb-containing compounds. An examination of these outliers with X-ray absorption near edge structures (XANES) spectroscopy revealed mixed valence of Ce, Eu, and Yb, with the average oxidation states of +3.20(1), +2.47(5), and +2.91(1), respectively, at room temperature. Magnetic behavior of A2Co12As7 is generally characterized by ferromagnetic ordering of Co 3d moments at 100-140 K, followed by low-temperature ordering of rare-earth 4f moments. The 3d-4f magnetic coupling changes from antiferromagnetic for A=Pr-Sm to ferromagnetic for A=Ce and Eu-Yb. Polarized neutron scattering experiments were performed to support the postulated ferro- and ferrimagnetic ground states for Ce2Co12As7 and Nd2Co12As7, respectively.

  17. Study of Crystal Defect Behaviors in CeO2-Based Electrolyte

    Institute of Scientific and Technical Information of China (English)

    Ma Zhifang; Liang Guangchuan; Liang Jinsheng

    2004-01-01

    The defect behaviors, such as fundamental point defect, defect pair formation and oxygen vacancy migration in ceria, were studied on the basis of energy minimization calculations. The result shows that anion Frenkel disorder is the preferred intrinsic disorder, and it is easier to be dissolved in CeO2 for CaO and SrO than for MgO and BaO via an oxygen vacancy compensation mechanism. The association energy of an oxygen vacancy with a substitutional cation depends on dopant cation radius. The favorable migration route for oxygen vacancy with the lowest migration energy is from the second neighbor site to another one.

  18. Thermal properties of some cerium compounds, particularly CeB6

    International Nuclear Information System (INIS)

    Using measurements of specific heat between 0.3 to 250K in the absence of a magnetic field, and from 2 to 250K for magnetic fields between 0 and 8T, it is shown that the γ 8 quadruplet is the fundamental level of the Ce3+ ion, the γ 8-7 separation energy being of the order of 500K. Detailed analysis suggests a lifting of degeneracy of the multiplet γ 8 in the paramagnetic phase, according to usual processes. Specific heat results obtained at very low temperatures reveal the importance of a significant gap in the spin wave energy spectra. Measurements under a strong magnetic field, around the two magnetic phase transitions of CeB6 show a spectacular reinforcement of the specific heat anomaly at a temperature of the order of TQ. Thermal conductivity of CEB6 is also studied in relation to the possible existence of a Jahn-Teller effect, likely to affect heat transfer by phonons. The problem of the different components of thermal transport prompts the analysis of the Weidemann-Franz law in the Kondo net, and also the study of the thermal conductivity of the compounds CeCu6, CeA12, the alloys Ce0.75La0.25B6, CexLa1-xCu6, and the fluctuating valence system SmB6. In all these bodies, an important contribution of phonons to electron transfer is shown. In the dense incoherent Kondo phase, it is not possible to envisage differences from the Weidemann-Franz law greater than those observed for highly diluted Kondo alloys

  19. Learning about the sm from extra dimensions

    International Nuclear Information System (INIS)

    This is a very short review about the possibility that the space-time has more than four dimensions and the implications of these extra dimensions on particle physics. The possibility that the forces of nature live in more than four dimensions gives a new perspective to high-energy physics. If gravity lives in large extra dimensions, the gravitational interaction can become strong at TeV energies. This requires a quantum theory of gravity (strings?) at TeV energies. This possibility allows to test quantum gravity at high-energy colliders such as the LHC. Another implication is that, at distances around a millimeter, we expect gravity to change from its 4-D behavior to a 6-D one. If the extra dimension is warped, the smallness of gravity could be explained by a exponentially small warp factor in the 5-D metric. This scenario does not require the SM fields to be localized on the 4-D boundary and predict KK resonances of TeV masses for any field living in the 5-D bulk. (author)

  20. Chtěli byste být mozkem v baňce?

    Czech Academy of Sciences Publication Activity Database

    Wiedermann, Jiří

    2006-01-01

    Roč. 51, č. 4 (2006), s. 272-282. ISSN 0032-2423 R&D Projects: GA AV ČR 1ET100300419 Institutional research plan: CEZ:AV0Z10300504 Keywords : kognitivní systémy * vtělenost * situovanost * vnitřní model světa Subject RIV: IN - Informatics, Computer Science http://dml.cz/handle/10338.dmlcz/141327

  1. Lifetimes of Excited Levels in 131Ce

    Institute of Scientific and Technical Information of China (English)

    LI Guang-Sheng; LI Xian-Feng; WEN Li-Jun; ZHENG Yong-Nan; ZHENG Yong; LIU Yun-Zuo; YUAN Guan-Jun; YANG Chun-Xiang; MENG Rui; ZHU Li-Hua; ZHANG Zhen-Long; WANG Yue; WANG Zhi-Min; WEN Shu-Xian; LU Jing-Bin; ZHAO Guang-Yi

    2004-01-01

    @@ The fusion-evaporation reaction 116Sn (1gF, p3n) 131 Ce at projectile energy of 95 MeV is used to populate high spin states in 131 Ce. The de-exciting γ-rays are detected in γ-γ coincidence measurement with Compton-suppressed BGO-HPGe detectors. Level lifetimes of 131 Ce were determined by using the Doppler shift attenuation method.The experimental results indicate that collectivity of 131 Ce is reduced relative to that of 130 Ce and it follows that deformation decreases with increase of the neutron number on the basis of systematic comparison of transition quadrupole moments for the light cerium isotopes.

  2. Pseudomonas chlororaphis Strain Sm3, Bacterial Antagonist of Pratylenchus penetrans.

    Science.gov (United States)

    Hackenberg, C; Muehlkchen, A; Forge, T; Vrain, T

    2000-06-01

    The interaction of Pseudomonas chlororaphis strain Sm3 and the root-lesion nematode Pratylenchus penetrans was investigated in three separate greenhouse experiments with soils from southern British Columbia, Canada. The bacteria were applied to the roots of strawberry plants and planted in unpasteurized field soils, with natural or supplemented infestation of P. penetrans. Nematode suppression in roots was evident after 6 or 10 weeks in all experiments. Root or shoot growth were increased after 10 weeks in two experiments. Population dynamics of P. chlororaphis Sm3 in the rhizosphere was followed using an antibiotic-resistant mutant of P. chlororaphis Sm3. There was no apparent correlation between bacterial density in the rhizosphere and P. penetrans suppression in strawberry roots and rhizosphere soil, although the soil with the highest nematode reduction also had the largest P. chlororaphis Sm3 population in the rhizosphere. PMID:19270964

  3. Fracture toughness studies in sintered SmCo5 magnets

    International Nuclear Information System (INIS)

    The fracture toughness of sintered SmCo5 magnets were systematically evaluated using both three point bend tests as well as Vickers indentation tests. These results were used for establishing the empirical dimensionless constant (χ) for evaluating indentation fracture toughness in SmCo5 magnets. The anisotropic behaviour of mechanical properties such as hardness, elastic modulus and fracture toughness was also investigated. - Highlights: • A strong anisotropy in the elastic modulus was observed in sintered SmCo5 magnet. • The hardness and fracture toughness did not show any prominent anisotropy. • Brittle cleavage fracture with (10 0) and (10 1) type cleavage planes observed. • Fracture toughness of SmCo5 magnets using Vickers indentation technique studied. • A suitable crack model and dimensionless coefficient value determined

  4. Discovery and characterization of smORF-encoded bioactive polypeptides.

    Science.gov (United States)

    Saghatelian, Alan; Couso, Juan Pablo

    2015-12-01

    Analysis of genomes, transcriptomes and proteomes reveals the existence of hundreds to thousands of translated, yet non-annotated, short open reading frames (small ORFs or smORFs). The discovery of smORFs and their protein products, smORF-encoded polypeptides (SEPs), points to a fundamental gap in our knowledge of protein-coding genes. Various studies have identified central roles for smORFs in metabolism, apoptosis and development. The discovery of these bioactive SEPs emphasizes the functional potential of this unexplored class of biomolecules. Here, we provide an overview of this emerging field and highlight the opportunities for chemical biology to answer fundamental questions about these novel genes. Such studies will provide new insights into the protein-coding potential of genomes and identify functional genes with roles in biology and disease. PMID:26575237

  5. Temperature dependence of the scintillation properties of Ce:GSO and Ce:GSOZ

    Energy Technology Data Exchange (ETDEWEB)

    Kurosawa, Shunsuke, E-mail: kurosawa@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Sugiyama, Makoto [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yanagida, Takayuki [New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Yokota, Yuui [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yoshikawa, Akira [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

    2012-10-21

    The light output and decay times of Ce:GSO and Ce:GSOZ scintillators depend on Ce concentration and temperature. We investigated the temperature dependence of the light output and the decay time for Ce:GSO and Ce:GSOZ doped with 0.3 (only GSO), 0.5, 1.0, and 1.5 mol% Ce. These samples were measured with a ruggedized photomultiplier (PMT) (Hamamatsu R6877A) at 175 Degree-Sign C (in the thermostat chamber). Up to 100 Degree-Sign C, the relative light output of all of the samples remained within 10% after correcting the PMT gain, which depends on the temperature. The decay times of the GSO and GSOZ samples with the identical Ce concentrations were equal. Moreover, the quenching energy values for all the samples were equivalent.

  6. Temperature dependence of the scintillation properties of Ce:GSO and Ce:GSOZ

    International Nuclear Information System (INIS)

    The light output and decay times of Ce:GSO and Ce:GSOZ scintillators depend on Ce concentration and temperature. We investigated the temperature dependence of the light output and the decay time for Ce:GSO and Ce:GSOZ doped with 0.3 (only GSO), 0.5, 1.0, and 1.5 mol% Ce. These samples were measured with a ruggedized photomultiplier (PMT) (Hamamatsu R6877A) at 175 °C (in the thermostat chamber). Up to 100 °C, the relative light output of all of the samples remained within 10% after correcting the PMT gain, which depends on the temperature. The decay times of the GSO and GSOZ samples with the identical Ce concentrations were equal. Moreover, the quenching energy values for all the samples were equivalent.

  7. Lattice dynamics of mixed-valent SmS

    International Nuclear Information System (INIS)

    Neutron scattering techniques have been used to measure the phonon dispersion curves for SmS in both the semiconducting and the metallic mixed-valent state. Large softening of the longitudinal acoustic phonon branches was found in the mixed-valent state, particularly for the [111] direction. It is apparent there is a strong coupling between the valence fluctuations and the phonons in the mixed-valent phase of SmS

  8. Concentration mechanism of piezoresistance in SmS

    International Nuclear Information System (INIS)

    Data on the SmS band structure are generalized and supplemented. A concentration model of the piezoresistance effect mechanism is proposed on the base of the data. It is shown that for production of a material with the piezoresistance exceeding the value for SmS at 300 K it is necessary to increase the contribution from 4f levels as far as possible

  9. Electric properties of SmS metallic modification

    International Nuclear Information System (INIS)

    Values of electric conductivity (rho and the Hall parameter Rsub(M) in thin films of samarium sulphide have been measured in semiconductor and metal modifications for the range of temperatures 1.5-300 K. Metal films of SmS with lattice constants 5.7 and 5.63 A are investigated. The temperature dependences of rho and Rsub(H) are theoretically explained. A zone scheme for metal modification of SmS is proposed

  10. Discovery of a metastable Al20Sm4 phase

    International Nuclear Information System (INIS)

    We present an efficient genetic algorithm, integrated with experimental diffraction data, to solve a nanoscale metastable Al20Sm4 phase that evolves during crystallization of an amorphous magnetron sputtered Al90Sm10 alloy. The excellent match between calculated and experimental X-ray diffraction patterns confirms an accurate description of this metastable phase. Molecular dynamic simulations of crystal growth from the liquid phase predict the formation of disordered defects in the devitrified crystal

  11. The Fourth SM Family Neutrino at Future Linear Colliders

    CERN Document Server

    Çiftçi, A K; Sultansoy, S

    2005-01-01

    It is known that Flavor Democracy favors the existence of the fourth standard model (SM) family. In order to give nonzero masses for the first three family fermions Flavor Democracy has to be slightly broken. A parametrization for democracy breaking, which gives the correct values for fundamental fermion masses and, at the same time, predicts quark and lepton CKM matrices in a good agreement with the experimental data, is proposed. The pair productions of the fourth SM family Dirac $(\

  12. Steam Electrolysis by Proton-Conducting Solid Oxide Electrolysis Cells (SOECs) with Chemically Stable BaZrO3-Based Electrolytes

    KAUST Repository

    Bi, Lei

    2015-07-17

    BaZrO3-based material was applied as the electrolyte for proton-conducting solid oxide fuel cells (SOECs). Compared with the instability of BaCeO3-based proton-conductors, BaZrO3-based material could be a more promising candidate for proton-conducting SOECs due to its excellent chemical stability under H2O conditions, but few reports on this aspect has been made due to the processing difficulty for BaZrO3. Our recent pioneering work has demonstrated the feasibility of using BaZrO3-based electrolyte for SOECs and the fabricated cell achieves relatively high cell performance, which is comparable or even higher than that for BaCeO3-based SOECs and offers better chemical stability. Cell performance can be further improved by tailoring the electrolyte and electrode. © The Electrochemical Society.

  13. 153Sm metallic-hydroxide macroaggregates. An improved preparation for radiation synovectomy

    International Nuclear Information System (INIS)

    A new type of preparation employing 153Sm metallic-hydroxide macroaggregates (153Sm-MHM) for radiation synovectomy was developed. The radiopharmaceutical was prepared by reacting the aqueous solution of 153SmCl3 with sodium borohydride solution in 0.5N NaOH. Microscopic analysis showed that 153Sm-MHM mean particle size was 4μm (range 1-15 μm) avoiding the formation of fine particles (153Sm-hydroxide macroaggregates preparations (153Sm-HM). Also, suspension properties as sedimentation rate, were better for 153Sm-MHM than for 153Sm-hydroxyapatite and 153Sm-HM. Biological studies in normal rabbits demonstrated high retention into de Knee joint space even at 48 h after administration of 153Sm-MHM (>99%). (author)

  14. Connection of thermopower and giant magnetothermopower with magnetic and structural heterogeneity in Sm{sub 0.55}Sr{sub 0.45}MnO{sub 3} manganite

    Energy Technology Data Exchange (ETDEWEB)

    Koroleva, L.I., E-mail: lyudkorolyova@yandex.ru [Moscow State University, Leninskie Gory 1, 119991 Moscow (Russian Federation); Morozov, A.S.; Jakhina, E.S. [Moscow State University, Leninskie Gory 1, 119991 Moscow (Russian Federation); Balbashov, A.M. [Moscow Power Institute, Krasnokazarmennaya street,14, 111250 Moscow (Russian Federation)

    2015-12-15

    It was first shown that the thermoelectric power in a magnetic semiconductor Sm{sub 0.55}Sr{sub 0.45}MnO{sub 3} is caused by ferromagnetic (FM) ferron-type nanoclusters and antiferromagnetic (AFM) CE-type nanoclusters with charge-orbital (CO) ordering. The presence of these clusters is caused by heavily Sr doping of a SmMnO{sub 3} compound, which replaced Sm ions. Thermoelectric power S and magnetothermopower ΔS/S has been studied in three samples: ceramics and two single-crystal samples. One of single-crystals was cooled in the air, another one was cooled in an oxygen atmosphere. The annealing in oxygen closes oxygen vacancies and, thus, increases the fraction of the CE-type AFM phase with the CO ordering which displaces the oxygen ions. S(T) curves of single-crystal sample cooled in the air and ceramic sample have a sharp increase starting from Curie temperature (T{sub C}) region and a slow decline till 325 K. At the same time {ΔS/S}(T) curves have a sharp minimum near T{sub C}=126 K, reaching the giant absolute value of 87% in the magnetic field H=14.17 kOe. This means that thermopower almost vanish with thermal destruction of FM clusters, i.e. thermopower is caused by these clusters in which crystal lattice is compressed. Oxygen cooled single-crystal's S(T) curves have a broad maximum near 270 K, including Neel temperature of CE-type clusters T{sub NCE}=240 K. {ΔS/S}(T) curve has a sharp minimum at the T{sub NCE} reaching the absolute value of 50% in H=13.2 kOe. The decrease of S is caused by destruction of CO order displacing oxygen ions in CE-type AFM clusters. Thus changed crystal lattice in nanoclusters of ferron type or AFM of CE-type makes the main contribution in thermopower in these three samples. - Highlights: • Thermopower S and magnetothermopower ΔS/S has been studied in Sm{sub 0.55}Sr{sub 0.45}MnO{sub 3}. • Sample consists of ferromagnetic and antiferromagnetic (AF) CE-type clusters. • Maxima of S and |ΔS/S| were observed at Curie

  15. On separation and purification of 151Sm in connection with creation of 151Sm based sources for NGR spectroscopy

    International Nuclear Information System (INIS)

    The data on 151Sm purification from rare earths, actinides and other elements present in the fraction which is a waste of fission products processing with the use of extraction-chromatography separation technique (hdehp is extracting agent, teflon is the carrier), are presented. Results of γ-spectrometric analysis of purified preparations are considered, as well as some problems of preparing 151Sm-based Moessbauer sources, namely, the choice of the chemical form of active material and source design

  16. AFe2As2 (A = Ca, Sr, Ba, Eu) and SrFe2-xTMxAs2 (TM = Mn, Co, Ni): crystal structure, charge doping, magnetism and superconductivity

    International Nuclear Information System (INIS)

    The electronic structure and physical properties of the pnictide compound families REOFeAs (RE=La, Ce, Pr, Nd, Sm), AFe2As2 (A=Ca, Sr, Ba, Eu), LiFeAs and FeSe are quite similar. Here, we focus on the members of the AFe2As2 family whose sample composition, quality and single-crystal growth are more controllable compared with the other systems. Using first-principles band structure calculations, we focus on understanding the relationship between the crystal structure, charge doping and magnetism in AFe2As2 systems. We will elaborate on the tetragonal to orthorhombic structural distortion along with the associated magnetic order and anisotropy, the influence of doping on the A site and the Fe site and the changes in the electronic structure as a function of pressure. Experimentally, we investigate the substitution of Fe in SrFe2-xTMxAs2 by other 3d transition metals, TM=Mn, Co or Ni. In contrast to a partial substitution of Fe by Co or Ni (electron doping), a corresponding Mn partial substitution does not lead to the suppression of the antiferromagnetic order or the appearance of superconductivity. Most of the calculated properties agree well with the measured properties, but several of them are sensitive to the As z position. For a microscopic understanding of the electronic structure of this new family of superconductors, this structural feature related to the Fe-As interaction is crucial, but its correct ab initio treatment still remains an open question.

  17. Unstable magnetic moments in Ce compounds

    International Nuclear Information System (INIS)

    The problems which are connected with the appearance or disappearance of local moments in metals are well reflected in the magnetic behaviour of Ce intermetallic compounds. This work describes experiments on two Ce compounds which are typical examples of unstable moment systems. The first of these is CeAl2 which at low temperatures, shows coexistence of antiferromagnetic order and the Kondo effect. Measurements are presented of the magnetization and the susceptibility in different magnetic field and temperature regions. An analysis of these measurements, using a model for the crystal field effects, shows the agreement between the measurements and the calculations to be reasonably good for CeAl2, but this agreement becomes worse upon decreasing Ce concentration. A phenomenological description of the observations is given. The second compound reported on is CeCu2Si2, the first 'heavy-fermion' superconductor to be investigated. The superconducting state is possibly formed by the quasi-particles of a non-magnetic many body singlet state, and not simply by the (sd) conduction electrons. This being a novel phenomenon, a number of experiments were performed to test this picture and to obtain a detailed description of the behaviour of CeCu2Si2. Measurements of the Meissner volume, confirmed the superconductivity to be intrinsic. (Auth.)

  18. Cost objective PLM and CE

    CERN Document Server

    Perry, Nicolas

    2010-01-01

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

  19. NOx conversion on LSM15-CGO10 cell stacks with BaO impregnation

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund; Andersen, Kjeld Bøhm; Kammer Hansen, Kent

    2012-01-01

    The electrochemical conversion of NOx on non-impregnated and BaO-impregnated LSM15-CGO10 (La0.85Sr0.15MnO3-Ce0.9Gd0.1O1.95) porous cell stacks has been investigated, and extensive impedance analysis have been performed to identify the effect of the BaO on the electrode processes. The investigation......O impregnation greatly enhanced the NOx conversion and at 400 degrees C and 9 V polarisation a BaO-impregnated cell stack showed 60% NOx conversion into N-2 with 8% current efficiency in 1000 ppm NO + 10% O-2. This demonstrates high NOx conversion can be achieved on an entirely ceramic cell without expensive...

  20. Phase equilibria in La(Y)-Ba-Cu-O systems and growth of high-Tc superconductor bulk single crystals

    International Nuclear Information System (INIS)

    The isobaric phase diagrams of BaO(La2O3)-CuO-CuO0.5 systems at a partial oxygen pressure of 0.021 MPa, the phase transition BaO2 right-reversible BaO at oxygen pressure up to 2.1 MPa have been studied and a flux method for growing bulk single crystals of YBa2Cu3O7-δ, La2CuO4, (LaSr)2CuO4, Nd2CuO4 and (NdCe)2CuO4 has been developed using a rotatable crucible which ensures separation of crystals from the melt

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

    International Nuclear Information System (INIS)

    The result of this thesis is, that the phonon dispersion of CePd3, 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 CePd3 than in the substances with NaCl-structure. The question whether such couplings realy exist can only be answered by further measurements. (orig.)

  2. Superconductivity above 90 K in the square-planar compound system ABa2Cu3O(6 + x) with A = Y, La, Nd, Sm, Eu, Gd, Ho, Er, and Lu

    Science.gov (United States)

    Hor, P. H.; Meng, R. L.; Wang, Y. Q.; Gao, L.; Huang, Z. J.

    1987-01-01

    Superconductivity has been found in the 90-K range in ABa2Cu3O(6 + x) with A = La, Nd, Sm, Eu, Gd, Ho, Er, and Lu in addition to Y. The results suggest that the unique square-planar Cu atoms, each surrounded by four or six oxygen atoms, are crucial to the superconductivity of oxides in general. In particular, the high Tc of ABa2Cu3O(6 + x) is attributed mainly to the quasi-two-dimensional assembly of the CuO2-Ba-CuO(2 + x)Ba-CuO2 layers sandwiched between two A layers, with particular emphasis in the CuO(2 + x) layers. Higher-Tc oxides are predicted for compounds with bigger assemblies of CuO2 layers coupled by Ba layers.

  3. Luminescence characteristics of doubly doped KLuS.sub.2./sub.:Eu,RE (RE = Pr, Sm, Ce)

    Czech Academy of Sciences Publication Activity Database

    Havlák, Lubomír; Jarý, Vítězslav; Rejman, M.; Mihóková, Eva; Bárta, J.; Nikl, Martin

    2015-01-01

    Roč. 41, Mar (2015), s. 94-97. ISSN 0925-3467 R&D Projects: GA ČR GA13-09876S; GA TA ČR TA01011017 Institutional support: RVO:68378271 Keywords : luminescence * white LED * energy transfer * rare earth doping * CIE coordinates Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.981, year: 2014

  4. Smích jako výraz spolupráce a konfliktu v dialogické komunikaci

    Czech Academy of Sciences Publication Activity Database

    Müllerová, Olga

    Opole : Uniwersytet Opolski, 2000 - (Gajda, S.; Brzozowska, D.), s. 87-94 ISBN 83-86881-27-5. [Style humoru. Kamien Slaski (PL), 07.10.1999-09.10.1999] Grant ostatní: RSS/OSSF(XC) 1619/186/1998 Institutional research plan: CEZ:AV0Z9061902 Subject RIV: AI - Linguistics

  5. Critically evaluated atomic transition probabilities for Ba I and Ba II

    International Nuclear Information System (INIS)

    Atomic transition probabilities for allowed and forbidden lines of Ba I and Ba II are tabulated, based on a critical evaluation of recent literature sources. The data are presented in multiplet format and are ordered by increasing excitation energies. (author)

  6. Ba{sub 2}phenanthrene is the main component in the Ba-doped phenanthrene superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Xun-Wang [Beijing Computational Science Research Center, Beijing 100084 (China); Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Science, Beijing 100190 (China); School of physics and electrical engineering, Anyang Normal University, Henan 455000 (China); Huang, Zhongbing, E-mail: huangzb@hubu.edu.cn [Beijing Computational Science Research Center, Beijing 100084 (China); Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062 (China); Lin, Hai-Qing [Beijing Computational Science Research Center, Beijing 100084 (China)

    2014-12-14

    We have systematically investigated the crystal structure of Ba-doped phenanthrene with various Ba doping levels by the first-principles calculations combined with the X-ray diffraction (XRD) spectra simulations. Although the experimental stoichiometry ratio of Ba atom and phenanthrene molecule is 1.5:1, the simulated XRD spectra, space group symmetry and optimized lattice parameters of Ba{sub 1.5}phenanthrene are not consistent with the experimental ones, while the results for Ba{sub 2}phenanthrene are in good agreement with the measurements. The strength difference of a few XRD peaks can be explained by the existence of pristine phenanthrene. Our findings suggest that instead of uniform Ba{sub 1.5}phenanthrene, there coexist Ba{sub 2}phenanthrene and undoped phenanthrene in the superconducting sample. The electronic calculations indicate that Ba{sub 2}phenanthrene is a semiconductor with a small energy gap less than 0.05 eV.

  7. Hydrogenation of the intermediate valence ternary stannides CeRhSn and CeIrSn

    OpenAIRE

    Chevalier, Bernard; Sebastian, C. P.; Pöttgen, Rainer

    2006-01-01

    CeRhSn and CeIrSn were synthesized from the elements via arc-melting. A single crystal from the CeIrSn sample was investigated on the basis of X-ray diffractometer data: ZrNiAl type, P2m, a=743.8(2), c=407.58(7) pm, wR2=0.0308, 352 F2 values and 14 variable parameters. An important structural feature of CeIrSn are relatively short Cesingle bondIr distances (4×303 and 1×308 pm). Hydrogenation of these ternary stannides leads to the formation of the new hydrides CeRhSnH0.8 and CeIrSnH0.7 which ...

  8. Enhanced time response of 1-in. LaBr3(Ce) crystals by leading edge and constant fraction techniques

    International Nuclear Information System (INIS)

    We have characterized in depth the time response of three detectors equipped with cylindrical LaBr3(Ce) crystals with dimensions of 1-in. in height and 1-in. in diameter, and having nominal Ce doping concentration of 5%, 8% and 10%. Measurements were performed at 60Co and 22Na γ-ray energies against a fast BaF2 reference detector. The time resolution was optimized by the choice of the photomultiplier bias voltage and the fine tuning of the parameters of the constant fraction discriminator, namely the zero-crossing and the external delay. We report here on the optimal time resolution of the three crystals. It is observed that timing properties are influenced by the amount of Ce doping and the crystal homogeneity. For the crystal with 8% of Ce doping the use of the ORTEC 935 CFD at very shorts delays in addition to the Hamamatsu R9779 PMT has made it possible to improve the LaBr3(Ce) time resolution from the best literature value at 60Co photon energies to below 100 ps

  9. Enhanced time response of 1-in. LaBr3(Ce) crystals by leading edge and constant fraction techniques

    Science.gov (United States)

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

    2015-09-01

    We have characterized in depth the time response of three detectors equipped with cylindrical LaBr3(Ce) crystals with dimensions of 1-in. in height and 1-in. in diameter, and having nominal Ce doping concentration of 5%, 8% and 10%. Measurements were performed at 60Co and 22Na γ-ray energies against a fast BaF2 reference detector. The time resolution was optimized by the choice of the photomultiplier bias voltage and the fine tuning of the parameters of the constant fraction discriminator, namely the zero-crossing and the external delay. We report here on the optimal time resolution of the three crystals. It is observed that timing properties are influenced by the amount of Ce doping and the crystal homogeneity. For the crystal with 8% of Ce doping the use of the ORTEC 935 CFD at very shorts delays in addition to the Hamamatsu R9779 PMT has made it possible to improve the LaBr3(Ce) time resolution from the best literature value at 60Co photon energies to below 100 ps.

  10. Enhanced time response of 1-in. LaBr3(Ce) crystals by leading edge and constant fraction techniques

    CERN Document Server

    Vedia, V; Fraile, L M; Udias, J M; Lalkovski, S

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-21

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

  12. Radiation streaming with SAM-CE

    International Nuclear Information System (INIS)

    The SAM-CE Monte Carlo code has been employed to calculate doses, due to neutron streaming, on the operating floor and other locations of the Millstone Unit II Nuclear Power Facility. Calculated results were compared against measured doses

  13. Magnetic and structural properties of the 'brown phase' solid solution Ba(Nd{sub 2-x}La{sub x})CuO{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Wong-Ng, W.; Swartzendruber, L.J.; Kaduk, J.A.; Bennett, L.H

    2003-07-01

    The compounds BaR{sub 2}CuO{sub 5} (R=Y and lanthanides) are well-known impurities that often coexist with the high T{sub c} superconductors, Ba{sub 2}RCu{sub 3}O{sub 6+x}. With R=La and Nd, brown color solid solutions (Ba{sub 1+x}R{sub 2-x}CuO{sub 5-x}) form instead of the 'green phase', BaR{sub 2}CuO{sub 5} (lanthanides with ionic radii smaller than that of Sm). A complete solid solution of Ba(Nd{sub 2-x}La{sub x})CuO{sub 5} exists with the tetragonal space group P4/mbm. Crystallographic studies of selected members (x=0.2, 0.6, 1.2, and 1.6) by X-ray Rietveld refinement technique showed the structure consists of RO{sub 8} and BaO{sub 10} cages, and square planar CuO{sub 4} units. As x increases in Ba(Nd{sub 2-x}La{sub x})CuO{sub 5}, the size of these RO{sub 8} and BaO{sub 10} cages increases. BaLa{sub 2}CuO{sub 5} was confirmed to be ferromagnetic at {approx}5 K; despite the isostructural property of BaLa{sub 2}CuO{sub 5} and BaNd{sub 5}CuO{sub 5}, the Nd-analog was found to be antiferromagnetic. As x in Ba(Nd{sub 2-x}La{sub x})CuO{sub 5} increases between 0 and 2, the amount of ferromagnetism increases.

  14. AMiBA, XMM, and Cluster Surveys

    CERN Document Server

    Liang, H

    2001-01-01

    The Array for Microwave Background Anisotropy (AMiBA) is an interferometric array of 19 dishes co-mounted on a steerable platform and operating at 95GHz. One of the main scientific aims of AMiBA is to conduct cluster surveys using the Sunyaev-Zel'dovich (SZ) effect. Here we explore the potential of AMiBA as a tailor-made SZ instrument for the study of cluster physics and cosmology via cluster surveys out to the epoch of cluster formation. In particular, we explore the potential of combining AMiBA cluster surveys with the XMM-LSS (Large Scale Structure) survey.

  15. Směrování v IP sítích s využitím sociálních sítí

    OpenAIRE

    Němec, Jan

    2014-01-01

    Tato bakalářská práce se věnuje problematice směrování dat v mobilních sítích. První část práce se zabývá přetěžováním mobilních sítí a popisem DTN a oportunistických sítí. V další části se práce zabývá popisem protokolů, které zapadají do konceptu směrování na základě sociálního statusu. Poslední část práce se zabývá návrhem a realizací simulačního modelu pro vybraný protokol z předešlé části.

  16. Morphological stability of Sm123 superconductor during peritectic solidification from Sm211 + L mixture

    International Nuclear Information System (INIS)

    The interface stability of the Sm 123 superconductor was analyzed in accordance with the constitutional undercooling criterion. As the single-crystal growth of the 123 phase is largely dependent on the growth-interface stability, a quantitative analysis was very much required. From this analysis, it was clarified that the constitutional undercooling must exist in the liquid when the 123 growth interface comes close to a 211 particle during the peritectic solidification. It was also predicted that the larger 211 particle radius, smaller volume fraction of the 211 particles, larger growth rate, or smaller imposed temperature gradient would cause easy occurrence of the constitutional undercooling ahead of the 123 growth interface. Taking into account the nucleation at the L/211 interface just ahead of the 123 growth front due to the constitutional undercooling, the transition of 123 growth from a planar-interface morphology to an equiaxed blocky morphology was investigated quantitatively and qualitatively

  17. Soil-to-plant transfer factors of radioactive Ca, Sm and Pd isotopes: critical assessment of the use of analogies to derive best-estimates from existing non-specific data

    International Nuclear Information System (INIS)

    45Ca, 151Sm and 107Pd are three radionuclides present in low to intermediate in activity radioactive wastes for which no soil-to-plant Transfer Factors (TF) values are available to be used in biosphere models for Ecological Risk Assessment. In the absence of specific radioecological studies, this work reviews and analyzes the existing literature for stable isotopes of Pd, Sm and Ca in order to derive best estimates for TF values that could be used as Transfer Factors. Alternative methods of extrapolation are also critically assessed. The values have been classified according to climatic zone, plant class and soil type for each element. The overall geometric mean TF values (for all plants and conditions) was calculated as 8.4E-02 for Pd, for which the value of radioRu in TRS-472 is also available. The mean TF for Sm was 4.2E-04. This value was lower than the TF values for radioactive Ce that are proposed as alternative values for Sm in TRS-472. The former may be relevant for long term assessments and the latter could possibly used to describe the short term 151Sm post-release behaviour. The mean value for Ca is 2.3E-01 but varies considerably among plants of a given class due to the variety of plant Ca uptake behaviors. Alternatively, to limit this variability, Ca data content for dry plant matter, as analyzed using the phylogenetic method, could be used to derive TF values if the conservation of isotopic ratio of 45Ca to stable Ca in soils and in plants hypothesis is taken into account. The TF for Ca in sub-tropical zones is 10-fold lower than in temperate zones. There is a lot of data available about exchangeable Ca in soil, which mean that we could calculate an available TF. The analysis shows that Ca bioavailability is also a key factor within transfer. - Highlights: • Derivation of TF values for Pd, Sm and Ca based on stable isotope literature. • Assessment of alternative values for Pd based on radioactive Ru values from TRS-472 (IAEA). • Assessment of

  18. Lepivost tkaniny nánosované vrstvou gumárenské směsi

    OpenAIRE

    Mahel, Jindřich

    2013-01-01

    Teoretická část diplomové práce popisuje základní skladbu gumárenské směsi, metody používané k jejímu zpracování a shrnuje dosavadní poznatky v oblasti lepivosti. Experimentální část se zabývá návrhem metod akcelerovaného stárnutí, pomocí nichž bylo provedeno testování vlivu UV záření, ozonu, teploty a vlhkosti na konfekční lepivost. Po slepení definovaným tlakem byla konfekční lepivost stanovena pomocí odlupovacího testu. Povrchy vzorků byly charakterizovány pomocí rastrovací elektronové mik...

  19. Expectations for LHC from Naturalness: Modified vs. SM Higgs Sector

    CERN Document Server

    Casas, J A; Hidalgo, I

    2006-01-01

    Common lore has it that naturalness of electroweak breaking in the SM requires new physics (NP) at Lambda < 2-3 TeV, hopefully within the reach of LHC. Moreover the Higgs should be light (m_h < 219 GeV) to pass electroweak precision tests (EWPT). However one should be prepared for "unexpected" (although admittedly unpleasant) results at LHC, i.e. no NP and/or a heavy Higgs. We revisit recent attempts to accommodate this by modifying the SM Higgs sector (using 2-Higgs-doublet models). We find that these models do not improve the naturalness of the SM, and so they do not change the expectations of observing NP at LHC. We also stress that a heavy SM Higgs would not be evidence in favour of a modified Higgs sector, provided certain higher order operators influence EWPT. On the other hand, we show that NP can escape LHC detection without a naturalness price, and with the pure SM as the effective theory valid at LHC energies, simply if the cut-off for top loops is slightly lower than for Higgs loops.

  20. AMiBA: System Performance

    OpenAIRE

    Lin, Kai-Yang; Li, Chao-Te; Ho, Paul T. P.; Huang, Chih-Wei Locutus; Liao, Yu-Wei; Liu, Guo-Chin; Koch, Patrick M.; Molnar, Sandor M.; Nishioka, Hiroaki; Umetsu, Keiichi; Wang, Fu-Cheng; Wu, Jiun-Huei Proty; Kestevan, Michael; Birkinshaw, Mark; Altamirano, Pablo

    2009-01-01

    The Y.T. Lee Array for Microwave Background Anisotropy (AMiBA) started scientific operation in early 2007. This work describes the optimization of the system performance for the measurements of the Sunyaev-Zel'dovich effect for six massive galaxy clusters at redshifts $0.09 - 0.32$. We achieved a point source sensitivity of $63\\pm 7$ mJy with the seven 0.6m dishes in 1 hour of on-source integration in 2-patch differencing observations. We measured and compensated for the delays between the an...