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Effects of pH on hydrothermal synthesis of boehmite from aluminum hydroxide were studied. The phases of products were identified by the X-ray diffraction method (XRD) and the morphologies of the particles were observed by scanning electron microscopy (SEM). From the XRD patterns, when the samples were prepared at pH ≥ 10, all the peaks were indexed as boehmite. On the other hand, the samples prepared at pH < 10 were involved the peak of gibbsite and boehmite.

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Perovskite-type KNbOSUB3/SUB particles were prepared by hydrothermal process using mixture of niobium oxide and KOH solution.Obtained sample were characterized by using XRD and SEM. Single phase of orthorhombic KNbOSUB3/SUB were obtained under 150SUPo/SUPCin reaction temperature,over 48h in reaction time and over 3.2 mol/dmSUP3/SUP in KOH concentration.KNbOSUB/3SUB having rod like morphology was obtained under the condition over 6.4mol/dmSUP3/SUP in KOH concentration.It was found that morphology of KNbOSUB3/SUB depended on KOH concentration.

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The microstructure of BaTiO₃ (BT) grown under hydrothermal conditions was observed. The transmission electron microscopic images and electron diffraction patterns indicate that BT grows selectively on rutile TiO₂ {110} and {100} surfaces with unique orientation relationships, such as [100]BT//(1-10)TiO₂, [001]BT//[111]TiO₂ and [100]BT//[100]TiO₂, [011]BT//[001]TiO₂. The relationships are consistent with that obtained in hydrothermally synthesized BaTiO₃ on a TiO₂ (110) single crystal.

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The influence of calcination-mechanochemical treatment on the structure and crystallization behavior of alumina and mechanochemical treatment of silica were investigated. A surface of alumina powder was mechanochemically activated using a planetary ball-milling and calcinations. On the other hand, a surface of silica powder was mechanochemically activated only using a planetary ball-milling. It was found that the crystallinity and the crystallite size increased with the increase of calcinations temperature. The mixture of activated powders with 15 wt.% KOH aqueous solution were cast into a mold and keep at 25oC under relative humidity of 50% until solidification. The solidification time increased with increasing calcinations temperature. This behavior is due to the destruction, by calcinations temperature, of the large aggregates of prepared powders, of the grain growth, and the phase transition of alumina takes place during calcinations. This proposed process is an attractive route for the shaping materials into ceramics without sintering process.

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Al₂O₃ / Nanoscale-Carbon-Network (NCN) composite was fabricated by gelcasting method and sintering under argon atmosphere. In this report, the effects of the difference of gel structure and kind of the monomer species on the carbonization of the polymer in green body fabricated by gelcasthingmethod. The gel structure in greenbody was changed by contorlling of initiator usage. The different kind of monomers, methacrylamide and acrylonitrile, were used. The graphite structure of carbon elements in samples were evaluated by Raman spectroscopy. Sintered samples shows the simmilar graphite structure. Effects of the gel structure and monomer species were not seen. It is thought that the thermal decomposition of functional group and cross-linking point was occured under sintering process. After then, remaind carbon elements were graphitized at high temperature.

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Influence of Mg2+ ions adsorption onto alumina particle surface by polyacrylic acid (PAA) in alumina slurry on sintering properties in alumina compacts was investigated. The adsorbed amount of Mg2+ ions was dominated by the adsorbed amount of PAA. The adsorbed amount of Mg2+ ions attained the maximum value at a [Mg2+]/[PAA monomer] ratio of 0.25. The optimum amount of PAA in well-dispersed alumina slurry led to almost 100 percent of Mg2+ ions adsorption onto alumina particle surface and to high relative density and homogeneous microstructure in the sintered body.

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The dopant effects of divalent cations, Zn²⁺, Ni²⁺, Mn²⁺ and Mg²⁺, on the sinterability of Y₂O₃ were systematically investigated with a doping concentration of 1 mol% at sintering temperatures in a range from 1100 to 1600^oC in air. The sinterability was improved by the doping and the effect was in the order of Zn²⁺ > Ni²⁺ > Mn²⁺ > Mg²⁺. The relative density of 99% was achieved at 1200^oC in Zn²⁺-doped Y₂O₃, while the relative density reached only 98% even at 1600^oC in undoped Y₂O₃. The grain sizes were increased by the doping. The grain sizes of the cation doped Y₂O₃s sintered at 1300^oC were 0.4-1.0um, whereas that of undoped Y₂O₃ was 0.3um. No abnormal grain growth was observed excepting Zn²⁺-doped Y₂O₃ sintered at 1500^oC. The dopant cations segregated along the grain boundaries without amorphous layers or secondary phase particles. The improved sinterability is probably related to the enhanced grain boundary diffusion due to the segregation of the dopant cation.

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Microstructural control is important to obtain the good reliability in thin-layer multilayer ceramic capacitors. This research aims to investigate the possibility for further improvement of microstructure and reliability on Ni- BaTiO3 multilayer capacitors via the kinetic approach. It indicates that the rapid sintering increases the ratio of core-shell grain, and the excellent reliability is obtained. Simultaneously, rapid sintering also significantly increases the continuity of nickel electrodes to obtain a high capacitive volumetric efficiency in high-capacitance multilayer capacitor.

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Materials in the single-nanometer region (less than 10nm) such as single-nano particles or nanoclusters have attracted attention in recent years. The single-nanometer region refers to the material dimension below about 10 nm. It is known in this region that substantial properties of a material, such as electric, magnetic, optical, thermal, and chemical properties, vary drastically. The authors' research group has synthesized a bulk solid consisting of grains of single-nanometer scale using particles of single-nanometer scale as a raw material and a bulk solid composed of a matrix and a second phase of single-nanometer scale (hereinafter referred to as a single nanocomposite), and studied on the structure and characteristics.

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Phenomena in pulsed wire discharge of Al wires to synthesize nanosized alumina powders were analyzed by using a high-speed infrared thermometer, in order to investigate the formation mechanism of nanosized alumina particles during the discharge. Temperatures of Al wires were measured during the experiments of pulsed wire discharge at various kinds of conditions. Abrupt increase of temperature and following decrease were recognized by the measurement in each pulsed wire discharge at all conditions. Another temperature increase was found after the first decrease of temperature in the cases of pulsed wire discharge in oxygen and air atmosphere.

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Cubic Aluminum nitride (c-AlN) is a promising component for electronic applications. In this study c-AlN coatings were synthesized by Atmospheric Plasma Spray (APS) process using reaction of feedstock Al powders with nitrogen plasma. Al powders were supplied to the plasma stream by carrier gas Ar and reacted with surrounding N2 plasma, then deposited onto substrate. The obtained coatings were c-AlN/Al mixture at 150 mm spray distance and the nitride content increases gradually with increasing spray distance, the coatings almost c-AlN at 300mm. However, coatings thickness decreased with increasing spray distance. Using carrier gas N2 enable to fabricate thick c-AlN coating.

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TiC_x films were prepared by laser chemical vapor deposition (LCVD) with tetrakis (diethylamido) titanium (TDEAT) and acetylene (C₂H₂) as the source materials. The effects of laser power (P_L), pre-heating temperature (T_pre) and fraction of C2H2 (F_C2H2) on the crystal structure, microstructure and deposition rate of TiC_x films were investigated. TiC_x films in a single phase with a cauliflower-like texture and columnar cross section were obtained. The compositional ratios of C to Ti (x) were in the range of 0.63-0.78 at a deposition temperature (T_dep) of 973 to 1143 K. The deposition rate (R_dep) of TiC_x films increased with decreasing F_C2H2, T_pre and P_L, showing a maximum Rdep of 60 µm/h at F_C2H2 = 0.4, P_L = 150 W, T_pre = 673 K.

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New preparation method of thick coating films has been developed. The thickness was over 1 micron, and the heat treatment temperature was below 200 degree C. Reaction control of silica precursor was one of the most important factors. The films were organic-inorganic Hybrid, but the mechanical strength was as high as float glass. Introducing ITO particles into the film, a heat-shielding coating was prepared. The coating had been adopted for automotive window firstly in the world since 2005. This new technique expanded the possible application fields of sol-gel coating.

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Capillary Electrophoresis Doping (CED) technique uses the transportation of molecules based on the electrophoresis phenomena in liquid under electric field. Rhodamine 6G (R6G) molecules are incorporated into the hybrid film synthesized from silicon and titanium alkoxide MAPTMS, TMOS and TTIP by sol-gel process. In order to clarify the migration of R6G molecules into the hybrid materials, pre-bake treatment is applied to the films before CED treatment. As the results, the migration of R6G was found strongly to depend on the vacant available spaces for R6G molecules.

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(100-x)GeO₂-xSiO₂ glasses (x = 0-100 mol%) were prepared by a sol-gel method to research the influences of the glass composition and glass structure on the formation of Ge²⁺ center. In the GeO₂ and GeO₂-SiO₂ glasses, the fluorescence bands due to the T₁->S₀, T₀ transitions of Ge²⁺ center appeared at the central wavelengths of 310 and 395 nm, respectively. 80GeO₂-20SiO₂ glass showed the strongest fluorescence bands of Ge²⁺ center. In (100-x)GeO₂-xSiO₂ glasses (x = 0-20 mol%), the broad fluorescence band related with carbon-residues appeared at the range of 320-600 nm and its intensity was increased with increasing of GeO₂.

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So far we have investigated EuO containing Al₂O₃-SiO₂ glasses for visible Faraday Rotation devices. In this study, to increase EuO content in glass, we used infrared-image furnace and rapid-melt-quenching. Here magnetic properties of xEuAl₂O₄-(100-x)SiO₂ glases (x=50, 60, 70), the latter of which was doped with or without Fe²⁺ ions, were reported.

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Precipitation of nano-ZnO crystallites was observed in the CaO-B2O3-ZnO-K2O-SiO2-Al2O3 glass after heat-treatment. Addition of Al2O3 and SiO2 affects selective crystallization of ZnO.TEM image showed that precipitation of ZnO crystallites of 500 nm occurred at the surface of the transparent crystallized glass.The present ZnO crystallized glass will be a functional material using the property of ZnO.

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Nano-crystallization of rutile and anatase was observed in a RO-B₂O₃-Al₂O₃-TiO₂-ZnO crystallized glass. Compared to Bi₂O₃ containing TiO₂-precipitated glass, transparency of the obtained glass in the visible region was improved. The main precipitated crystalline phase of the present crystallized glass was anatase, which was a phase different from the previous reports. We have discussed the effects of ZnO on the crystallization behavior as well as photocatalytic behavior for application as transparent photocatalytic materials.

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In this paper, we will present the time-resolved observation of pressure wave generation in fs laser processing inside a silica glass and show how the intensity of the pressure wave depends on the pulse duration. We found that the amplitude of the pressure wave increases more sensitively as the excitation energy increases when the pulse duration is longer. This means that the amplitude of the pressure wave can be tuned more precisely with a laser of shorter pulse duration.

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We have examined thermal and optical properties of BaO-TiO₂-GeO₂ (BTG) glass in which fresnoite crystallites were precipitated after heat-treatment. We focused on the correlation between crystallization behavior and ΔT_bulk-ΔT_powder value, where ΔT_bulk and ΔT_powder indicate ΔT (Tx-Tg) of bulk sample and ΔT of powdered, respectively. The obtained results showed that surface crystallization and transparency of the crystallized glass were strongly correlated with the ΔT_bulk-ΔT_powder value. Both refractive index and wavelength dispersion was dominated by an amount of TiO₂ in the glass. These results are useful to design the BTG optical devices with high optical nonlinearity.

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We demonstrate that femtosecond modification of anisotropic nanostructure, which can indicate form birefringence created by sub-wavelength scale interfaces of defect structures in fused silica, with a time constant of ± 200 fs. We interpret this dynamics of anisotropic light-matter interaction in terms of lowering threshold for structural defect formation and the enhanced coherency of the electron plasma wave. Such anisotropic photosensitivity in homogeneous material also indicates a remarkable non-reciprocity.

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