To improve the performance of manganese oxides applying to electrochemical capacitor as electrodes, the hydrothermal electrochemical deposition method was used for preparing the manganese oxide films. The optimum synthesis conditions and each synthesis factor (such as solution concentration, synthesis temperature, deposition time and deposition voltage) contributing to the specific capacitance of synthesized manganese oxides were approached by using Taguchi experimental design method. The synthesis temperature and concentration of manganese acetate were the two main factors influencing the specific capacitance. The manganese oxide films deposited under the solution concentration of 0.2 mol L^-1, synthesis temperature of 100°C, deposition time of 60 s, and deposition voltage of 0.8 V showed the optimum specific capacitance of ca. 126.35 Fg^-1. Porous and needle-like morphology enhanced the specific capacitance of manganese oxide film but restricted the stability performance of charge/discharge. The crystalline Mn₃O₄ and denser morphology revealed the good stable ability of capacitive performance after 600 cyclic-life test.

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Mechanical properties of Ag⁺/Na⁺ ion-exchanged aluminosilicate glasses are investigated. The aluminosilicate glass samples with the thickness of 1 mm and homogeneous Ag⁺/Na⁺ concentrations were prepared via the ion exchange in the molten salt at 450°C and the following post-heating in the ambient atmosphere. Measured Young's modulus, Vickers hardness and fracture toughness in a dry nitrogen atmosphere change nonlinearly with increasing Ag/(Ag+Na) ratio, and show the maximum values, 75 GPa, 560 kg/mm² and 0.84 MN/m^3/2 around Ag/(Ag+Na)=50%, respectively. Fully exchanged glass shows the same modulus 70 GPa as that of the mother glass and the smallest hardness and toughness, 500 kg/mm² and 0.74 MN/m^3/2, respectively. The calculated yield stress decreases from 2.59 GPa to 2.30 GPa with increasing Ag/(Ag+Na) at more than 60% region. Coexistence of Ag⁺/Na⁺ induces mixed cation effect, and gives a maximum to the elastic modulus at Ag : Na=1 : 1. Additionally, the yield stress of glass is decreased with increasing Ag⁺ concentration by the difference of the effect on Al-O-Si network between Ag⁺ and Na⁺.

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The influence of raw BaTiO₃ (BT) powder characteristics such as particle size and crystallinity on the microstructure as well as the electrical properties of X7R-type multilayer ceramic capacitors with Ni internal electrodes (Ni-MLCCs) was investigated in the BT-Ho-Mg-Mn system. For the MLCC samples, the dielectric constant at room temperature decreased with a decrease in the grain size. In particular, it drastically decreased for the grain sizes of less than 200 nm. Furthermore, the dielectric constant was considerably dependent on the tetragonality (c/a) of the raw BT powder, whereas the full-width at half maximum (FWHM) had little effect on the electrical properties. The samples obtained from the raw BT powder with high c/a showed the inhibited grain growth and they consisted of a large number of core-shell grains having clear domain patterns in the core region. Accordingly, the sample with high c/a showed high dielectric constant and good temperature characteristics with respect to capacitance.

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The heat-treatment of a mixture of Li₂CO₃ and R₂O₃ (R=La and Nd) in CO₂ induced the formation of a rare-earth oxycarbonate followed by the lithium incorporation into the rare-earth oxycarbonate during the heating process. The formed oxycarbonates were related to the hexagonal structure with P6₃mmc. The c-lattice parameter increased and the a-lattice parameter slightly decreased with an increase in the lithiation degree. The lithiation degree y for the R₂O_2+2y(CO₃)_1-yLi_2y system increased with an increase in the heat treatment temperature in CO₂.

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The total amount of superoxide (O₂ ^-) and peroxide (O₂ ^2-) occluded in micropores of calcium aluminosilicate (Ca₁₂Al₁₀Si₄O₃₅; mayenite) was determined from their reaction with pulsed H₂. Mayenite was prepared by calcining precursor hydrogarnet, which was synthesized via hydrothermal reaction of a stoichiometric mixture of CaO, Al₂O₃, and amorphous SiO₂. Since a part of Ca²⁺ in hydrogarnet could be substituted with other metal ions by adding a corresponding metal nitrate to the mixture, metal-substituted mayenite was also prepared by calcining the precursor metal-substituted hydrogarnet. Substitution of Ca²⁺ with other metal ions markedly increased the amount of oxide anions reacting with pulsed H₂ and the amount was largest for Cu-mayenite. The amount of O₂ taken up in oxide anion-deficient mayenite was found to be largest for Cu-substituted mayenite. It was also confirmed that reaction between oxide anions in Cu-mayenite and pulsed H₂ and that between oxide anion-deficient Cu-mayenite and pulsed O₂ were completed even under a very high flow rate of the carrier gas, corresponding to the space velocity of >10⁵ h^-1. A large amount of occluded oxide anions reacting with H₂ together with their quick regeneration in oxide anion-deficient mayenite leads us to expect that Cu-mayenite is applied as a new material with an excellent oxygen storage capacity to an automotive three-way catalyst.

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Glass fibers with a diameter of~100 μm are drawn by just pulling up melts of 40BaO•20TiO₂•40SiO₂ glass, and transparent crystallized glass fibers consisting of nonlinear optical fresnoite Ba₂TiSi₂O₈ nanocrystals (particle size:~100-200 nm) are fabricated by crystallization of glass fibers. Precursor glass fibers and nanocrystallized glass fibers are etched chemically using a meniscus method, in which an etching solution of 0.1 wt%-HF/hexane is used. Glass fibers with sharpened tips (e.g., the taper length is~L=200 μm and the tip angle is~θ=23°) are obtained. It is found that etched nanocrystallized glass fibers also have sharpened tips (L=50 μm, θ=80°). Compared with precursor glass fibers, nanocrystallized glass fibers show a high resistance against chemical etching in a 0.1 wt%HF solution. Although sharpened tips in nanocrystallized glass fibers do not have nanoscaled apertures, the present study suggests that nanocrystallized glass fibers showing second harmonic generations would have a potential for fiber-type light control optical devices.

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A variety of polycrystalline alumina and sapphire surfaces were successfully covered with ruby crystal layers by the isothermal evaporation of MoO₃ flux. The grown ruby layers exhibited transparent-red, and the ruby-coated alumina materials showed beauty and luster in the as-grown state without skilled cutting and polishing. For sapphire substrates, the ruby layers were epitaxially grown on their surface. Furthermore, the growth model of ruby layers was discussed, and aluminum molybdate (Al₂(MoO₄)₃) was found to be the intermediate compound for the growth of ruby crystals.

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In this study, porous ZrO₂ ceramics were successfully prepared by an electrophoretic depositions (EPD) method with gas generation in the aqueous ZrO₂ slurry. Especially, this aqueous EPD process in combination with a sintering step formed porous ZrO₂ with a number of unidirectionally aligned continuous pores. Also, adding starch into ZrO₂ slurry resulted in the increase of porosity of ZrO₂ ceramics. Thus, applying the aqueous EPD process has a great advantage in environmental issues and cost reduction for fabricating porous ceramics.

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Erbium-doped silica-based glass for optical amplifiers is fabricated from silica powders by a compression-forming method using a cold isostatic pressing (CIP) technique. Silica powders are prepared from slurry containing fumed silica with submicrometer diameter and erbium source by granulating using a spray drier. The average diameter of the granulated powders is 50 μ and about 150 times as large as that of the fumed silica. The silica powders are packed in a rubber mold and are compressed by CIP. It is found from thermal analysis that the compressed powders can be degreased PVP at 600°C. After degreasing at 600°C, the compressed powders are sintered by a sintering process using an electric furnace or a gas burner. The compressed powders can be vitrified by using not the electric furnace but the gas burner. The existence of Er ions in the glass sintered by the gas burner is confirmed from UV-VIS spectra.

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We prepared dense (67.9 vol%) green bodies from high-purity spherical fused SiO₂ powder by using the floc-casting technique. A firing schedule was determined from data obtained by the in-situ measurement of the sintering shrinkage of the compacts. Accordingly, we fired the compacts at 1400°C for 30 min in air to obtain transparent SiO₂ glass sintered bodies. The XRD patterns of the sintered bodies were the same as those before sintering. No crystallization was observed in the sintered bodies. Moreover, the sintered bodies with a thickness of 2 mm had a high transmissivity (>85%) in the visible range.

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