The effect of yeast extract on the cytotoxicity and the colloidal behavior of positively charged polystyrene latex （PSL） nanoparticles （NPs） toward yeast cells were investigated. Confocal observation revealed that the cells were alive and the NPs were dispersed when adding the yeast extract into 5 mM NaCl, results that were quite different from the toxicological effects in 5 mM NaCl without the yeast extract. This is because the negatively charged organic molecules in the yeast extract adhered on the NPs, leading that the NP surface changed negative. Additionally, the PSL NPs showed no toxicity when the yeast cells were incubated in the perfect media （yeast extract and glucose）. These results suggest that the PSL NPs display little or no toxicity toward the environmental microorganisms. Nanocolloidal probe atomic force microscopy revealed that the adhesion forces between the PSL NP and the yeast cell drastically decrease when adding the yeast extract.

A solid-state mechanochemical reaction between ZnO and Fe₂O₃ to form ZnFe₂O₄ was kinetically analyzed based on the mechanical energy applied to the reactants. A powder mixture of ZnO and Fe₂O₃ was mechanochemically treated by a planetary ball mill at different revolution speeds of the vessel for changing the impact energy and collision frequency of grinding balls. An increase in the conversion of ZnO to ZnFe₂O₄ with increasing milling time was well described in terms of a solid-state reaction model taking into account three-dimensional diffusion of reactants. A plot of the reaction rate constant on semi-logarithmic scale as a function of reciprocal of the translational kinetic energy of reactant particles gave a straight line with a negative slope. This relationship suggests that the rate constant depends on the kinetic energy and collision frequency of reactant particles, indicating that kinetics of the mechanochemical reaction may be explained by statistical mechanics and thermodynamics.

The mechanical synthesis of a high-purity LiNi_0.5Mn_1.5O₄ cathode powder under ambient conditions is an important issue for a low-cost fabrication of lithium-ion batteries. In this paper, we have investigated the mechanical synthesis of LiNi_0.5Mn_1.5O₄ granules by using a Ni/Mn composite as a precursor to improve the cathode properties. The Ni/Mn composite powder, which was prepared by drying of MnO₂ in nickel nitrate solution, was used on mechanical treatment with Li₂CO₃. The LiNi_0.5Mn_1.5O₄ nanoparticles were synthesized by the mechanical method and granulated at the same time. The LiNi_0.5Mn_1.5O₄ granules did not contain any particles of starting materials. The LiNi_0.5Mn_1.5O₄ cathode prepared from this high-purity powder exhibited the improved discharge capacity at a high-voltage region of 4.7V.

We attempted to use Zn₂（Ti_xSn_1－x）O₄ solid solutions as a host material for a new phosphor. Eu^3＋ ion was used as an activator for the phosphor. In general, larger Eu^3＋ ion was not easy to diffuse into the smaller crystal structure of the host material by solid state reaction. At the present stage, the sizes of the starting powders are controlled by ball-milling. When the powder sizes were under 0.080μm, red emission was observed around 620 nm by the 4f-4f transition of Eu^3＋ ion in the （Zn_1.96Eu_0.04）（Ti_0.3Sn_0.7）O_4±δ phosphor. However, a yellow emission was observed when the particle sizes were larger than 0.1μm and/or Ti content was larger than Sn content. The yellow emission was caused by defects in the crystal. We assumed that the difference in the emission color was caused by the difference in the occupation-site for Eu^3＋ ion in the crystal structure.

This study showed the development of the colloidal technique for enhancement of the interfacial adhesion between the carbon fibers and the thermoplastic resin, such as nylon. To improve the interfacial adhesion between carbon fiber and nylon, the nylon particles in the polymer colloids were adsorbed on the carbon fiber using electrophoresis. The amount of nylon particles adsorbed on the carbon fiber was able to be controlled changing the applied voltage in the electrophoresis for a short time. Accordingly, the interfacial shear strength between the carbon fiber and the nylon was also controlled through the surface modification by the present system. This method was a basic technique for making carbon fiber-reinforced thermoplastic （CFRTP） with high performance.

The rate of particle orientation for a colloidal processing in magnetic field was examined experimentally by the temperature dependence of viscosity of slurry. Slurry consisting （Sr, Ca）₂NaNb₅O₁₅ particles and photopolimarization resin was used and consolidated by UV irradiation reaction after various duration times in the strong magnetic field. The degree of orientation of a sample increased with the duration time. Viscosity of the slurry decreased remarkably with an increasing in temperature from 20℃ to 50℃. The reduction of the viscosity of slurry contributed to make the hydrodynamic torque small, and the duration time in the magnetic field become short. In a magnetic field at 6 T, the time for sufficient orientation was achieved within 10 seconds in spite of using condensed slurry with 45 vol％. The result will contribute to spread this fabrication process.

Powders consisting of Si-based nanosheets were synthesized by Ca atom extraction from CaSi₂ powders using inositol hexakisphosphate （IP6）, which is known as a phytate for metal storage. The raw CaSi₂ powders were simply immersed in a diluted IP6 solution, then dried. It is noted that the Si-based nanosheets were easily exfoliated from the powders, to expose the surfaces corresponding to the Si｛111｝ planes of the nanosheet. The structural and infrared optical properties of the Si-based nanosheets were examined. In addition, Si-based nanostructures were also synthesized by metallic atom extraction from SrSi₂, BaSi₂ and Mg₂Si using the IP6 solution. It is found that the nanosheets mainly including amorphous phase were obtained for IP6-treated SrSi₂, BaSi₂ and Mg₂Si powders. Moreover, amorphous Si-based nanostructures were synthesized from CaSi₂ using citric acid and malic acid solutions. It is demonstrated that the morphological property of the synthesized Si-based nanostructures depends on the silicide templates and the solutions. New simple synthesis technique of Si-based nanostructures is proposed using the acid solutions.

Tetragonal barium titanate single crystal was synthesized by hydrothermal treatment of Ba-Ti-OH precursor slurry with 10 vol％ ethylene glycol aqueous solution. Oxygen site was partially occupied by hydroxide ion in the synthesized barium titanate. The tetragonality of synthesized crystal disappeared by heat treatment, indicating that substituted hydroxyl group stabilized the tetragonal crystalline structure. The dielectric constant of prepared barium titanate particles was measured by slurry method using propylene carbonate as a dispersion medium. The results from dielectric constant of slurry indicated that the intermediate structure between tetragonal and cubic is effective for high dielectricity.

Zeolites, crystalline porous aluminosilicates, are widely used as solid catalysts in various petroleum and petrochemical processes. Cerium oxide, CeO₂, is much useful catalyst for numerous organic reactions and environmental catalytic reactions due to its Lewis acid-base and redox properties. Therefore, mechanochemical preparation of compounded particles of micro-sized ZSM-5 zeolite and CeO₂ nanoparticles was investigated in this research. During the mechanochemical treatment by using a powder composer, the crystallinity of ZSM-5 zeolite was almost retained. Bead-milling treatment of CeO₂ agglomerates can be changed into highly dispersed CeO₂ nanoparticles, and the following mechanochemical treatment with ZSM-5 can successfully give the compounded particles. The compounded particles showed the catalytic activity originating from ZSM-5 zeolite to promote the catalytic cracking reactions of various hydrocarbons.

In this study, we fabricated Aluminum Nitride （AlN） ceramics containing AlN whiskers grown by direct nitridation of Al-Si binary melt. We evaluated their microstructures and thermal conductivities. The samples containing 4 vol％ of the AlN whiskers were fully densified at 1650℃ for 10 min using spark plasma sintering （SPS） and Y₂O₃-CaO-B sintering additives. The microstructures were almost isotropic. This means the whiskers do not work as a seed crystal for the formation of the columnar microstructures, but a sintering additive for promoting the densification at the initial stage of sintering. Si impurity contained in the whiskers is suggested to work as a part of the sintering additives. The thermal conductivity of the sample containing whiskers was around 80 W･m^-1･K^-1, which is comparable to that of the sample not containing whiskers.

Recently, development of lead-free piezoelectric materials has been receiving great attention because of environmental issues. Among several ferroelectric oxides, BaTiO₃ has been attractive as a potential candidate. This review report describes the processing of nonreducible BaTiO₃-based ceramics for multilayer piezoelectric actuator devices using base metal internal electrodes. Reduction-resistant BaTiO₃-based ceramics were fabricated by appropriately modifying the chemical composition in Mn-doped （Ba,Ca）TiO₃ ceramics. To improve their electrical properties, grain-oriented ceramics were also prepared by the reactive templated grain growth method using platelike BaTiO₃ and CaTiO₃ particles. The electrical properties of the BaTiO₃-based ceramics, sintered in the reducing atmosphere （oxygen partial pressure below 0.1 Pa）, were markedly improved as a result of fabricating grain-oriented samples.