Laser-induced crystallization in glass is a new crystallization technique of glass materials. This article reports the progress in the patterning of nonlinear optical crystal lines on the glass surface by laser irradiation techniques. Two techniques for the patterning of crystal lines have been developed, i.e., rare-earth atom heat processing and transition metal atom heat processing, in which continuous-wave lasers such as Nd:YAG laser (wavelength: λ = 1064 nm) are irradiated onto the glasses containing rare-earth ions such as Sm³⁺ and Dy³⁺ or transition metal ions. We introduced these atomic laser heating techniques for the patterning of nonlinear optical crystals (BiBO₃, β-BaB₂O₄, Ba₂TiGe₂O₈ and LiNbO₃) and clarified the features (morphology, orientation, optical nonlinearity) of crystal lines.

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A new biomimetic process for apatite coating on polymeric materials has been developed. In this process, the surface of a polymer is modified with amorphous calcium phosphate (ACP), and then the polymer is immersed in a supersaturated calcium phosphate solution. The new biomimetic process has the advantages of safety, simplicity, and applicability to various types and forms of polymeric materials. By adding a biomolecule (such as protein, antibacterial agent, or DNA) to the supersaturated solution, immobilization of a biomolecule into the apatite coating while retaining the intrinsic biological activity of the biomolecule is possible. As a result of this, the base polymer would possess biological activity to control cell behaviors (such as adhesion, proliferation, and differentiation), in addition to good biocompatibility owing to the apatite. Hence, the new biomimetic process and the resulting composites have a wide variety of biomedical applications including tissue engineering scaffolds, percutaneous devices, and gene delivery carriers.

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Continuous SiC fiber-reinforced SiC matrix composites (SiC_f/SiC) have been considered to be a key material as structural components for aerospace and energy fields. This paper reviews novel fabrication process of continuous SiC_f/SiC composites with high performance based on interfacial and microstructure control and our approach to improvement of mechanical and thermal properties of SiC_f/SiC composite based on modeling and analysis. The simple fabrication process of two-dimensional SiC_f/SiC composite using sheet stacking and hot-pressing based on interfacial and microstructure control was developed, and dense SiC_f/SiC composite with excellent mechanical and thermal properties was successfully obtained. Furthermore, novel fabrication process of SiC_f/SiC composite using EPD process was proposed and it was demonstrated that EPD process is expected to be an effective way to control the fiber/matrix interface and the microstructure of SiC_f/SiC composite with high performance. Interfacial properties of SiC_f/SiC composite were quantitatively evaluated by push-in test using nanoindenter, and these quantitative results well agreed with the results on their mechanical properties, and these results lead to the material design of the SiC_f/SiC composite with high mechanical properties and the optimization of its fabrication process. Simple model of thermal conductivity of SiC_f/SiC composite based on series model of multilayered structure was suggested by our experimental data, and higher thermal conductivity of SiC_f/SiC composite was successfully achieved by microstructure control.

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We succeeded in synthesizing Ba₂RBiO₆ (R = La, Ce, Nd, Sm, Eu, Gd, and Dy) with a double-perovskite structure. Its photocatalytic activities were then investigated for a degradation of methylene blue (MB) solution and gaseous 2-propanol (IPA). High photocatalytic activities were observed under visible light irradiation and also a rare earth dependence of photocatalytic activities in the IPA degradation. We carried out first-principle calculations of the band structure based on the all-electron Full-potential Linear Augmented Plane-Wave (FLAPW) method and discuss the relationship between the high photocatalytic activities and the band structure in this paper.

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Stable sols with a homogeneous dispersion of ZnO nanoparticles were prepared by heating zinc hydroxide (Zn(OH)₂) precipitate in an ethylene glycol solution of zinc nitrate hexahydrate (Zn(NO₃)₂·6H₂O) at 308 K. The formation of ZnO nanoparticles occurred within 1 h when the mixed solution of Zn(OH)₂ precipitate and 0.05 mol/L of the ethylene glycol solution of zinc nitrate hydrate was heated at 308 K. The obtained sol was homogeneous, and no aggregation of the ZnO nanoparticles was observed. The formation process of ZnO nanoparticles in the mixed solution of Zn(OH)₂ and the 0.05 mol/L ethylene glycol solution of zinc nitrate hexahydrate was examined by measuring changes in the UV-VIS spectra of the obtained sol and the XRD patterns of the particles separated from the sol. Strong absorption due to the electron transition between the band gap of ZnO appeared during heating at 308 K for 1 h. When the heating time decreased, the shift in the absorption edge to a shorter wavelength was observed. This shift in the absorption edge would be related to changes in the particle size during the formation process of ZnO nanoparticles. Furthermore, the photoluminescence spectra of the obtained ZnO nanoparticles were examined. The intensity of photoluminescence increased with increases in the concentrations of zinc nitrate hydrate in the ethylene glycol solution.

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Porous silicon carbide ceramics were prepared from a polysiloxane, carbon black, SiC filler, sacrificial templates (co-polymer microbeads) and Al₂O₃-Y₂O₃ additives by a carbothermal reduction and subsequent sintering process. The effect of the sintering temperature on the microstructural development and structural characteristics of the porous ceramics was examined by scanning electron microscopy (SEM), X-ray diffractometry (XRD), and Raman spectroscopy. The polysiloxane-derived silicon carbide (PDSC) specimens showed a more homogeneous pore distribution than the powder-processed ones. Both the PDSC and powder-processed specimens contained only β-SiC when sintered at 1700°C. On the other hand, the PDSC specimens sintered at 2000°C revealed the formation of free Si clusters, detected by XRD and Raman spectroscopy, whereas the powder-processed ones showed only the SiC phases. The formation of such Si clusters was effectively suppressed by adding an excess of carbon during the synthetic process. Raman spectroscopy revealed the existence of carbon layers in the 1700°C-sintered specimens, which were hardly detectable in the 2000°C-sintered ones.

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Solidification of SSS (sewage sludge slag) has been carried out by the geopolymer binder technique at 80°C steam conditions mixed with CFA (coal fly ash). Geopolymer liquor was prepared by mixing Na-disilicate solution of 1.27 S.G. (specific gravity) and 10 M NaOH solution in 3:1 proportion. Obtained monolithic materials were subjected to physical measurements such as 3-point flexural strength, bulk density and expansion-shrinkage. Subsequently, matrix as well as filler chemical compositions were analyzed by SEM-EDX. Results showed SSS is an active filler similar to CFA and maximal strength was reached by blending SSS with CFA in 1:3 proportion. P₂O₅ and CaO components of SSS strongly contributed to the polycondensation of the geopolymer liquor other than theoretically expected Al₂O₃ and SiO₂ components.

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The MAO coating was prepared on biomedical alloy by micro-arc oxidation (MAO) in sodium aluminate (NaAlO₂) solution using pulsed bipolar power supply. It was found that the coating consists of O, Al, Ti and Ni, and Ni concentration in the coating surface is much lower than that of Ni in the NiTi substrate. The concentration of sodium aluminate (NaAlO₂) solution has an influence on the surface morphologies, surface roughness, corrosion resistance and bonding strength. XRD analysis reviewed that MAO coating formed in solution of 0.05 M sodium aluminate (NaAlO₂) is amorphous, the coating was composed of crystallize γ-Al₂O₃ when the sodium aluminate (NaAlO₂) concentration is from 0.075 M to 0.15 M. The intensity of γ-Al₂O₃ peaks increased with increasing the concentrations of NaAlO₂. The corrosion resistance and bonding strength of the MAO coatings increased with the increasing NaAlO₂ concentration. Especially, the bonding strength of MAO coating to NiTi substrate was up to 28.0 MPa when NaAlO₂ concentration is up to 0.15 M.

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Nanocomposite particles of Al₂O₃-doped ZnO prepared by mechanical treatment were used for fabricating ZnO ceramics. TEM observations revealed that Al₂O₃ nanoparticles uniformly existed on a ZnO particle. The sintering body fabricated using the composite powder prepared by this mechanical treatment process had more uniform and finer microstructures than that fabricated using the powder mixture prepared by conventional wet mixing. The ZnO ceramics prepared by the mechanical treatment exhibited higher electrical conductivity than those prepared by the conventional wet ball milling process.

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Refractory castables were prepared from 85 mass% graded SiC slab waste as an aggregate and 15 mass% of either 50% or 80% alumina cement using the suitable amount of gauging water. The prepared castable samples were subjected to different firing temperatures 20°C, 800°C, 1000°C, 1300°C , 1400°C, 1500°C and 1600°C. The sintering parameters (bulk density and apparent porosiy), mechanical properties (cold crushing strength) as well as refractory properties (refractoriness, thermal shock resistance as well as refractoriness under load) were tested according to the international standard specifications. The mineralogical compositions of the fired castables were investigated using X-ray diffraction analysis (XRD). The microstructure of some selected fired castable samples was testes using scanning electron microscope (SEM) attached with energy dispersive X-ray unit (EDX). Castable samples containing 50% alumina cement showed good sintering, mechanical as well as refractory properties limited up to 1400°C while those of castable samples containing 80% alumina cement are extended to 1600°C. The improved properties of the fired castables are correlated with the matrix advantage system; mullite-SiC-CA₆-corundum resulting from the reaction of the fine grains of SiC with calcium aluminate cement. The relatively improved properties of castables containing 80% alumina cement is due to the high purity of the cement and hence the little content of the low melting phases formed which affect adversely the refractory properties of castable samples containing 50% alumina cement. SiC refractory castables bonded by CAC can be nominated as refractory lining for the ancillary areas (coolers, nozzles, burner, and cone) and preheaters of the rotary cement kiln.

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The luminous efficacy of Ce:Y₃Al₅O₁₂ (YAG) glass-ceramic (GC) phosphor increased with the increasing crystal size of precipitated Ce:YAG, while the light scattering coefficient decreased. This increase in luminous efficacy can be attributed to the decrease in light scattering loss owing to the decrease in light scattering coefficient with increasing Ce:YAG crystal size. According to Mie scattering theory, the reason for the decrease in the light scattering coefficient is the decrease in light scattering cross-section per unit volume with increasing Ce:YAG crystal size.

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The carbothermal reduction and nitridation (CRN) reactivity of alumina (Al₂O₃) to aluminum nitride (AlN) under a flow of nitrogen was investigated for transition aluminas (γ- and δ-Al₂O₃) and α-Al₂O₃ with the same particle size and mixing homogeneity with carbon. The aluminas were obtained by calcining a (hydroxo)(succinato)Al(III) complex under a flow of nitrogen, argon, or mixed gas of nitrogen and carbon monoxide. The transition aluminas were converted to AlN without any transformation into α-Al₂O₃. The CRN reactivity of Al₂O₃ decreased in the following order: γ-Al₂O₃ > δ-Al₂O₃ >> α-Al₂O₃. The difference in their CRN reactivities was attributed to the difference in the ratio of AlO₄ sites to AlO₆ sites among the three phases. The CRN reactivity decreased with increasing crystallinity.

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TiN-cubic boron nitride (cBN) composites were prepared from TiN and cBN powders by spark plasma sintering at temperatures from 1600 to 1800°C for 600 s under a uniaxial pressure of 100 MPa. The densification, phase transformation, microstructure and mechanical properties of the TiN-cBN composites were investigated. TiN-BN composites originally containing 10 to 30 vol% cBN without a phase transformation from cBN to hexagonal BN (hBN) were obtained at a sintering temperature of 1600°C. The densification of the TiN-BN composites was retarded with increasing cBN content. The phase transformation from cBN to hBN in the TiN-BN composites started at 1650°C and was completed at 1800°C. The Vickers hardness and fracture toughness of TiN-BN composite, originally containing 10 vol% cBN, prepared at 1600°C were 17 GPa and 3.6 MPa·m^1/2, respectively.

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Plate-like BaTiO₃ particles with a size of about 200 nm in thickness and 3 μm in width were prepared by using a novel solvothermal soft chemical process in ethanol and water-ethanol mixed solvents. A layered titanate of H_1.07Ti_1.73O₄ with a lepidocrocite-like structure and plate-like nanoparticle morphology was used as the precursor, and solvothermally treated in the Ba(OH)₂ solution to prepare the BaTiO₃ nanoparticles. The formation reaction, particle morphology, nanostructure, and crystal-axis-orientation of the plate-like BaTiO₃ nanoparticles were studied by XRD, FE-SEM, and TEM. The plate-like BaTiO₃ nanoparticles are formed by an in situ topotactic structural transformation reaction. The crystallinity and particle morphology can be controlled by changing the fraction of ethanol in the solvent, Ba(OH)₂ concentration, and reaction temperature. The plate-like BaTiO₃ nanoparticles are polycrystalline particles constructed from spherical nanocrystals which are arranged in the same crystal-axis orientation in each plate-like particle, and show a high degree orientation in [110] direction, being suitable for preparing oriented BaTiO₃ ceramic materials with high performance.

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A photo-initiated process via femtosecond pulse induced heterogeneous nucleation in zinc ammine complex (Zn(NH₃)₄²⁺) based aqueous solution without catalyst and surfactant, followed by thermal treatments for crystal growth into zinc oxide (ZnO) nanorods, was investigated. Hexagonal ZnO nanorods of diameter ≤ 100 nm with smooth planes and length ≤ 1 μm were grown with laser irradiation and successive thermal treatment. The studies show that pH value in the aqueous solutions remarkably effect on morphology of the ZnO nanostructure. Due to the localized high supersaturation of precursor, the hexagonal nucleation was induced by laser irradiation.

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The effects of various buffer layers on the InN growth were studied by using atomic force microscopy (AFM), X-ray diffraction (XRD), KOH wet etching and photoluminescence (PL). GaN or InN buffers with various temperatures and conditions were prepared for the InN growth by using plasma-assisted molecular beam epitaxy (PAMBE). For GaN buffers, the InN polarity was controlled by the GaN polarity. Namely, high temperature buffers (HT, 765°C-880°C) led to -c polar InN with better quality, while intermediate-temperature buffers (IT, 500°C-650°C) to +c polar InN with lower quality. When InN buffer was used, the quality of main InN was lower than that on GaN buffer. This reason is attributed to the twist misorientation (rotation of InN unit cell along c-axis) in InN/InN-buffer/sapphire structure. This drawback has been effectively suppressed by a longer substrate nitridation, or by inserting a GaN buffer between sapphire and InN buffer. By comparing the InN grown on GaN, InN or (GaN + InN) buffer, we concluded that GaN grown at about 800°C was the optimal buffer because it had atomically flat surface and led to -c polar InN with small misorientation.

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Mullite-cubic boron nitride (cBN) composites were prepared using mullite and cBN powders by spark plasma sintering at temperatures of 1500-1700°C for a holding time of 600 s under a pressure of 100 MPa. Densification, microstructure and hardness of the mullite-BN composites and the phase transformation of cBN to hexagonal BN (hBN) in the mullite-BN composites were studied. Fully dense mullite-cBN composites originally containing 10-30 vol% cBN with relative density of over 95% were obtained at 1500°C without the phase transformation of cBN. At the cBN content of 10 vol%, the densification of the mullite-BN composite was not inhibited. When more than 20 vol% cBN was added to mullite, the densification of the mullite-BN composites was suppressed. The phase transformation of cBN in the mullite-BN composites started at 1600-1700°C. The hardness of mullite-BN composites originally containing 20 vol% cBN sintered at 1500°C without the phase transformation of cBN reached a maximum value of 16 GPa.

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Direct measurement of the switching voltage between pre-breakdown and breakdown regions in the current-voltage (I-V) characteristics of zinc oxide varistors is difficult, and the varistor voltage is normally measured at 10^-3 A as a reference current. In this study, using a simple I-V measurement system, the change in leak current associated with device degradation was measured to determine the switching voltage of commercial zinc oxide varistors. The switching voltage was found to be 45.3 V while the varistor voltage as determined from the I-V characteristics at a reference current of 10^-3 A was 47.9 V. This new method can be effectively used for measuring the switching voltage of varistors.

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A radio frequency magnetron sputtering method, specifically tailored for the deposition of thick, adherent cubic boron nitride (c-BN) thin films on silicon substrates, was developed. The surface morphology of the boron nitride thin films was changed by altering the noble gases (Kr, Ar, Ne, and He) in the chamber present during the sputtering. The sample prepared in the gas with He showed especially good adhesion. This method enabled us to grow a 1.7-μm-thick c-BN thin film on a Si(100) substrate in only rare gases at a low temperature for the first time. Fourier transform infrared spectroscopy (FT-IR) indicated that the fraction of sp³-bonded BN in the thick films was above 60%.

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The reasons for the change in the mechanical strength of porcelain tableware measured by the impact test with the restraint conditions are discussed. The compressive test was performed on various restraint conditions to investigate the relation between the deformation and the destructive load of tableware. The failure impact energy increased up to 62% by the restraint condition. As the result of the compressive test, it was observed that the angle of backstop affected the deformation of the tableware and the restraint weight changed the destructive load.

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