The leak-current of the electrode-supported cells with Ce_0.9Gd_0.1O_1.95 electrolyte have been discussed. The observed OCV was lower than the theoretical one and obviously depended on the supporting electrodes: the anode-supported cell showed a relatively higher OCV than the cathode-supported one. In the case of both supported cells, the leak-currents, which were obtained from the calculation, decreased dramatically with increasing current density. The efficiencies are approximately 50% for the anode-supported cell and approximately 40% for the cathode-supported one, respectively, when fuel utilization of H2 is 100%.

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Steam electrolysis was carried out using a micro tubular ceramic reactor with Zr_0.89Sc_0.1Ce_0.01O_1.95 electrolyte 10%H₂+Ar mixture gas was used as steam carrier gas, and 18% steam was supplied to inside of the ceramic reactors. The cell voltage 1.43 V at 0.1 A/cm² was observed at 923K. The heat generation from low current density was observed by electro-chemical technique. Voids and incursion of Zr were confirmed in CGO buffer layer. Such factors nearby surface probably caused increase in the ohmic resistance and electrode over potential.

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In this study, pyrochlore-type oxide electrocatalyst was tried to use as an alternative electrocatalyst, because it is stable in acid solution and is lower cost than Pt-based catalysts. Pyrochlore-type oxides were tried to synthesize by wet chemical methods, and the electrocatalytic properties, such as oxygen reduction performence, etc., were investigated in an acidic condition.

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La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) is a candidate electrolyte material for the low temperature solid oxide fuel cell (LT-SOFC) for its superior oxide-ion conductivity. In this study, the reactivity between the LSGM and anodes such as Ni-LSGM, Ni- Gd0.9Ce0.1O2 (GDC), Ni-10mol%Sc2O3-1mol%CeO2-89mol%ZrO2 (ScSZ) and Ni-8mol%Y2O3-92mol%ZrO2 (YSZ) was examined. The LSGM thin film was deposited on the anodes using the radio frequency (RF) magnetron sputtering method and characterized electrochemically

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Porous self-bonded silicon carbide (SiC) ceramics were fabricated at temperatures ranging from 1700 to 1850 ^oC using SiC, silicon, and three different carbon (C) sources, including carbon black, phenol resin, and xylene resin. The effects of the Si:C ratio and carbon source on properties were investigated as a function of sintering temperature. It was possible to fabricate self-bonded SiC ceramics with porosities ranging from 36% to 53%. The maximum strength of self-bonded SiC ceramics was obtained when the carbon source was carbon black and the Si:C ratio was 5:1.

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Porous silicon carbide ceramics were prepared from a carbon-filled polysiloxane by carbothermal reduction. The fabrication process involved three step: (i) the pyrolysis of polysiloxane at 1100^oC, which leads to the conversion of polysiloxane to silicon oxycarbide (SiOC); (ii) the carbothermal reduction of SiOC and C mixture at 1450^oC, which converts the mixture to a SiC ceramic; and (iii) liquid phase sintering of the SiC using Al₂O₃-Y₂O₃ as a sintering additive at various temperatures.
By controlling the template content and sintering temperature, it was possible to adjust the porosity in a range of 39% to 88%. The flexural and compressive strengths of porous SiC ceramics with ~40% porosity were ~100 MPa and ~290 MPa, respectively.

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Sintering additives play an important role not only on the densification but also on the microstructural development and the resulting properties of SiC ceramics. In this work, the effect of additive composition on the sinterability of SiC powders was investigated. Various additives (B, Al, AlN, Si₃N₄, CuO, and Sc₂O₃-AlN) were investigated for sintering SiC powders. The Sc₂O₃-AlN composition showed the highest sintered density (99.8%) among the compositions investigated herein. The effect of annealing on sintered density and microstructure was investigated for the composition. Microstructure, electrical resistivity, and strength of some selected SiC ceramics are presented.

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This work reports on the effect of CeO₂ and/or Cr₂O₃ addition on the mechanical properties of Al₂O₃-mullite-ZrO₂ composites. The amount of additives added was 1.5wt%CeO₂, 1.5wt%Cr₂O₃ and the mixture of 1.5wt%CeO₂ and 1.5 wt%Cr₂O₃. Bulk composites have been sintered by using pressure-less sintering method. Phases, microstructure, density and porosity of sintered composites were characterized. Flexural strength and fracture toughness were also determined. The results from mechanical tests showed that the highest flexural strength was obtained with the mixture of CeO₂ and Cr₂O₃ addition, while the highest fracture toughness was obtained with CeO₂ addition.

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In this study, barium titanate (BaTiO3, BT) and strontium titanate (SrTiO3, ST) nanocube particles were successfully prepared by solvothermal method. As the raw materials, barium hydroxide, strontium hydroxide and titanium dioxide nanoparticles were used, and as the solvent, ethanol and 2-methoxy ethanol were used. Size of the obtained BT and ST nanoparticles was around 20 nm, and their crystal structures were assigned to cubic m-3m symmetry. Using these nanoparticles, their accumulation was investigated.

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We synthesized La_2-xRE_xCuO_4-δ(RE=Sm, Y) bulk samples and thin film samples. Then, we investigated the relationship between physical properties, crystal structure and electric conductivity by changing Sm, Y content and synthetic process. The main phase kept T'structure, although T structure and precursor were observed as a sub-phase depending on preparation condition. When the resistivity showed the metallic behavior, the resistivity remarkably decreased at low temperature area, but they did not show zero resistivity. In addition, we analyzed the crystal structure by the Rietveld method from synchrotron X-ray diffraction, and investigated the relation among the oxygen deficiency, the site, and the electric conductivity.

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We have studied oxygen diffusion in BaTiO3 ceramics. Oxygen diffusion was carried out by vapor-solid exchange method. Oxygen tracer profile was measured by secondary ion mass spectrometry (SIMS). In order to effect of grain boundary and impurity on oxygen diffusion path, the distribution of oxygen tracer was measured by scanning ion image using fine focused Cs ion beam. We observed the blocking effect by grain boundary on oxygen diffusion.

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Compositional dependence of the valency state of Cr ions in fluorophosphate and fluoride glasses was investigated on the basis of those absorption spectra. The effect of matrix on the valency sate of Cr ions was discussed.

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Soft x-rays are generally understood to be x-rays in the energy range 100-3,000 eV, and they have energies higher than those of extreme ultraviolet light. Soft x-rays cover an energy range of importance for spectroscopic studies of many elements in the periodic table. IThe structural changes and nanophase separation dynamics of sodium borosilicate glasses were investigated using soft x-ray spectroscopy. We found that the coordination number of boron, which is significant for the phase separation dynamics, can be clearly detected by the absorption spectra of the soft x-ray. The fraction of four-coordinated boron (N4) decreased by adding the Al2O3 component. These results are discussed in relation to the calculations based on the density functional theory (DFT) and DVXa methods.

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Local structure of Bi ion in Bi-doped silica glass that is a new infrared luminescent material is analyzed by instrumental analysis, such as, ESR, EXAFS, XPS, and 27Al-NMR. These analytical results show that the valence state of Bi ion is pentavalent and the origin of luminescent center is derived from a structure that the Bi5+ ion with 6-fold coordination exists close to the Al3+ ion with 6-coordination. According to these structural data and spectroscopic properties, we are considering on an energy diagram of Bi luminescent center.

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Super-spherical glasses were prepared by a Surface-tension Mold (StM) technique using the wetting property between glass melt and substrate. A super-spherical lens has attracted much attention because it can act as Solid Immersion Lens (SIL) with the super-resolution, which circumvents the optical diffraction limit. In previous work, we showed that the obtained micrometer-size super-spherical glasses with the Na2O-CaO-SiO2 system realized the optical functionality of the SIL. In this study, we investigated the dependence of the super-spherical shape of glass prepared by StM technique on the shape and size of initial glass particle in order to know the controllability of super-spherical shape in the StM technique.

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