Taking advantage of the tubular pores in SiO₂ and TiO₂ matrices, Au and Ag were deposited inside the pores, which worked as one-dimensional confined spaces, to form Au and Ag nanoparticles. The obtained nanocomposites displayed various characteristics all of which were related to the localized surface plasmon resonance of Au and Ag nanoparticles. Three attempts to confirm the possibilities of their practical applications to polarizers, photocatalysts, and photoanodes of solar cells were undertaken.

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A novel approach was developed for synthesizing sialon in an air atmosphere, and then used to obtain O′-sialon bonded corundum composite ceramics (O′-sccc) by a sintering reaction process in an air atmosphere. The morphology, microstructure, and properties of the O′-sccc were investigated. The process of forming sialon by air atmosphere sintering is discussed. It was found that a novel configuration, using fused white alumina, alumina powder, and ferro silicon nitride powder, allowed the synthesis of sialon without a controlled nitrogen atmosphere furnace.

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In this study, Ca²⁺-Cr³⁺ co-doped YAG were prepared by solid state reaction. Various solid-solution phase were formed, e.g. Y₃Al₅O₁₂, YAlO₃ and YCaAl₃O₇. Phase composition and microstructure of the prepared materials were characterized by XRD and SEM. The effects of the Cr³⁺ single doping concentration, Ca²⁺/Cr³⁺ co-doping concentration and Ca²⁺/Cr³⁺ doping ratio on the infrared emission characteristics of the doped YAG were investigated. The experimental results demonstrated that the infrared emissivity of YAG could be significantly enhanced by Ca²⁺-Cr³⁺ co-doping and the optimum Ca/Cr doping ratio was estimated to be 1.0.

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We measured the Soret coefficients of alkali oxides in binary alkali borate glass melts. The alkali borate glasses, 15(mol %)Li₂O–85B₂O₃, 15Na₂O–85B₂O₃, and 15K₂O–85B₂O₃, were encapsulated in platinum capsules and heat-treated at 1000°C with a temperature gradient in a tube furnace. After the heat treatment, the compositional distribution of the glass sample was measured by Raman spectroscopy. The Soret coefficients of the alkali oxides Li₂O, Na₂O, and K₂O increased with the atomic numbers of the alkali metal ions. This indicates that alkali oxides more easily have high concentration in cold regions as the atomic numbers of the alkali metal ions in the alkali oxides increase. This result provides new information about the diffusion properties in glass melts.

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The effect of Si addition was studied for the purpose of the improvement of microstructure of MgFe₂O₄ particles prepared from a malic acid complex. There were no traces of any impurity phase in Si-doped and pure MgFe₂O₄ powders both in XRD measurements. When Si atoms were doped to MgFe₂O₄, crystallite growth of MgFe₂O₄ was remarkably suppressed, and the lattice volume increased up to 10 mol% Si monotonously. SEM observations revealed that MgFe₂O₄ powders show a granulation shape such as the aragonite and each particle tightly interconnected each other, whereas smaller particles compared with pure MgFe₂O₄ were observed for Si-doped MgFe₂O₄. Also, it was found that the amount of mesopore increases by Si doping. Further, XPS and XAS measurements suggested that Si atoms exist in MgFe₂O₄ crystal.

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Titanium oxide (TiO₂) powders with equal specific surface area but with different crystalline phase (rutile and anatase) were modified with Fe using FeCl₃ or Fe(acac)₃ with two modification techniques: metal cluster grafting (MCG) and chemisorption calcination cycle (CCC). Then, visible-light photocatalytic activity of the obtained powders was evaluated by the decomposition of gaseous 2-propanol (IPA). The modified powders possessed almost identical morphology and specific surface area. Visible light photocatalytic activity was increased remarkably by the Fe-modified rutile-phase TiO₂ prepared using both techniques. The photocatalytic activity, action spectra, and the binding energy shift of oxygen suggest that these two techniques provide different mechanisms for visible light photocatalytic activity.

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