Pervaporation of ethanol from ethanol/water mixture solution using surface-modified mesoporous silica membranes has been carried out. The mesoporous silica layers were prepared on commercially available porous alumina tubes by dip-coating in a series of silica sols. Subsequently, organosilane compounds with different alkyl chain lengths [C_nH_2n+1(CH₃)₂SiCl; n = 1, 3, 8, 12, and 18] were covalently reacted to the surface of these mesoporous layers with high coverage. Surface-modified mesoporous silica membranes showed ethanol permselectivity and the total flux increased with increasing ethanol concentration in feed composition and feed temperature. Ethanol separation factors in the range from 7.90 to 8.24 and total flux of 2.76–2.89 kg·m⁻²·h⁻¹ were obtained by pervaporation at 323 K and at 5 wt % ethanol feed composition using surface modified membranes. In the presence of 1 wt % acetic acid in a ternary model fermentation (5 wt % ethanol–94 wt % water–1 wt % acetic acid), separation factor and total flux were decreased, and this tendency was minimized by increasing pH above pK_a^⊖ (pK_a^⊖ = 4.74 at 298 K) and changing HOAc to OAc⁻ ions in the feed solution.

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Low temperature sintering of β-spodumene ceramics with low coefficient of thermal expansion (CTE) was attained using Li₂O–Bi₂O₃ sintering additive. High purity β-spodumene could be synthesized at 1150°C using high purity and fine amorphous silica, γ-alumina and lithium carbonate powder mixture via the solid state reaction route. The mixture was calcined at 800°C, pulverized, compacted, and sintered with or without the sintering additive at 800–1350°C for 2 h. The relative density reached 95% for the sample sintered with 3 mass % of Li₂O–Bi₂O₃ additive at 1050°C for 2 h. As a result, sintering temperature could be lowered about 200°C by adding the sintering additive, compared with the sintering temperature previously reported. The flexural strength of the sample sintered with 3% of Li₂O–Bi₂O₃ additive at 1050°C for 2 h was 118 MPa. Its CTE (from R.T. to 800°C) was 0.2 × 10⁻⁶/K. Its dielectric constant was 8.2 with loss tangent of 1.4%.

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A simple method for making a porous SiC body through a polymeric route at one firing processing was demonstrated by the sacrificial filler template approach. By incorporating sacrificial pore-forming plastic powder, PMMA microbeads, into liquid preceramic polymer, AHPCS, and losing it after the polymer was hardened, a preceramic porous body was formed. As a consequence of systematic examination of the effects of particle size and mixture ratio of the powder, an AHPCS-derived porous SiC body was reproducibly formed without critical crack initiation. It was enabled only when the polymer was sufficiently contained to make a strong skeletal structure with the sacrificial plastic particles closely distributed. The porous microstructure would contribute to efficient gas emission and uniform thermal shrinkage during polymer pyrolysis, which reduced internal pressure and crack-causing thermal stress.

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α-Al₂O₃ film was first deposited on Ti(C, N)-based cermet substrate by laser chemical vapor deposition (LCVD) in a CO₂–H₂ atmosphere. The effects of atmosphere, laser power (P_L), total pressure (P_tot) and deposition temperature (T_dep) on the crystal phase and microstructure were investigated. α- and γ-phase mixture film was prepared at T_dep = 833 K. Single phase α-Al₂O₃ film was obtained at T_dep = 903 K. The surface morphology of α-Al₂O₃ film changed from a cauliflower-like to a granular-like structure with increasing T_dep and decreasing P_tot. α-Al₂O₃ film with a well-developed facet structure was obtained at P_tot = 0.6 kPa and T_dep = 933 K.

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Highly porous calcium phosphate (CaP) ceramics were fabricated by freezing foamed aqueous CaP suspensions with various CaP contents (15, 20, and 25 vol %) containing polyvinyl alcohol (PVA) as the binder and emulsifying agent. All the samples fabricated showed uniformly dispersed macropores, which were created by air bubbles introduced in the suspensions. In addition, aligned micropores were formed in the sintered CaP walls as a replica of the preferentially grown ice dendrites during freezing when CaP contents of 15 and 20 vol % were used. The overall porosity decreased from 83 to 73 vol % with increasing initial CaP content from 15 to 25 vol %, whereas the compressive strength and elastic modulus increased significantly from 1.2 ± 0.2 to 4.7 ± 0.9 MPa and from 20 ± 11 to 163 ± 42 MPa, respectively. The samples showed good biocompatibility, as assessed by the in vitro cell test using a pre-osteoblast cell line.

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Thermal hysteresises of electrical resistance, accompanying with a structural phase transition, in epitaxial VO₂ films have been successfully reduced to 1°C or less by doping Ti or Nb ions. We considered that owing to the metal-ion-substitutive structural defects induced by doping metal ions into VO₂ films, the structural phase transition easily occurred without superheating or supercooling. In Nb-doped VO₂ films, the hysteresis disappeared at a lower doping level than Ti-doped VO₂ films. The maximum values of the temperature coefficient of the resistance of V_0.91Ti_0.09O₂ and V_0.982Nb_0.018O₂ films, which exhibited non-hysteretic MI transitions, were −24.8%/°C at 46°C and −21.6%/°C at 19°C, respectively.

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The perovskite oxynitride SrTaO₂N as a promising candidate for lead-free dielectric materials has been studied with a special emphasis on the structural characterization using neutron powder diffraction. SrTaO₂N powders were prepared by means of ammonia nitridation via precursors obtained from a soft chemistry method and a solid state reaction route. All the products crystallized in tetragonal I4/mcm space group with only slight variation in the lattice constant, e.g., a = 5.7023(1) Å and c = 8.0786(1) Å for the soft-chemistry derived sample. Neutron diffraction analysis suggested the short-range O/N ordering involving a cis configuration in TaO₄N₂ octahedra together with large anionic displacement within the ab plane on their axial position in the average crystal lattice. These facts are associated with local tilting of the TaO₄N₂ octahedra which is likely to play a key role in the unusual dielectric behavior of SrTaO₂N.

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This study investigates the thermoluminescence produced when calcium sulfate codoped with Eu³⁺ and Pr³⁺ (CaSO₄:Eu³⁺,Pr³⁺) is irradiated with X-rays. CaSO₄:Eu³⁺,Pr³⁺ was synthesized by heating CaSO₄·2H₂O:Eu³⁺,Pr³⁺ at 1050°C. The CaSO₄:Eu³⁺,Pr³⁺ exhibited red emission upon X-ray irradiation and subsequently emitted an afterglow. The afterglow time was lengthened by adding Li⁺ ions to the phosphor, and the afterglow time for a Li/Ca atomic ratio of 0.002 was 120 min. Thermoluminescence peaks were observed at 130, 160, 240, 260, and 355°C upon heating CaSO₄:Eu³⁺,Pr³⁺. The luminances of the thermoluminescence peaks increased with increasing X-ray irradiation time. Only the luminance of the peak near 100°C decreased when CaSO₄:Eu³⁺,Pr³⁺ was irradiated with X-rays. Therefore, the afterglow is considered to have originated from the thermoluminescence peak near 100°C that had a trap depth of about 0.20 eV.

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MgF₂ porous nanoparticle coatings with SiO₂ binder were formed on glass substrates by solgel method. The samples were exposed to fluoro-alkyl silane (FAS) vapor and heated at 150°C to give water repellency. We measured surface roughnesses and static contact angles of water of the samples and examined the relation between surface roughnesses and contact angles. Scanning Probe Microscopy (SPM) confirmed that the FAS treatment had no effect on the surface roughness. In the autoclave temperature region of 100–180°C, the higher the autoclave temperature was, the larger the surface roughness was. The sample prepared from the 100°C autoclaved sol had the minimum surface roughness of 4.1 nm and showed the minimum static contact angle of 115°. On the other hand, the sample prepared from the 180°C autoclaved sol had the maximum surface roughness of 9.5 nm and showed the maximum static contact angle of 134°.

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The difference in corrosion behavior between alumina-spinel and alumina-magnesia castables in a steel slag was investigated with emphasis on the composition of spinel phase. The spinel primarily-added to the alumina-spinel castable had the stoichiometric composition, whereas the spinel forming secondarily in the alumina-magnesia castable was in an alumina-rich composition. The model reaction between sintered spinel and slag revealed that the stoichiometric spinel was highly wettable to slag and the molten slag deeply penetrated into the sintered body. In contrast, the alumina-rich spinel was less wettable. It was found that the alumina-rich spinel changed into stoichiometric one at the interface between spinel and slag, and that an iron-alumina spinel formed following to dissolution of the excessive alumina into slag. The increase in alumina content seemed to increase the viscosity of the slag, leading to retardation of penetrative wetting of slag to the alumina-rich spinel.

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A composite was prepared by impregnating epoxy resin into a fused α-alumina pellet, which was synthesized by calcinating aluminum-nitrate-immersed α-alumina fibers. The thermal conductivity of this composite in the planar direction is about 2.7 times higher than the predicted value of a composite containing α-alumina particles with the same alumina content.

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Different types of amorphous solids derived from Na- and K-zeolite A were prepared by mechanical or post-mechanical thermal treatments and changes in the atomic arrangement of these solids were characterized by high-energy X-ray diffraction (HEXRD). HEXRD measurements revealed that the structures of the amorphous solids after mechanical and post-mechanical thermal amorphization were different from one another. These amorphous solids were recrystallized to zeolite and the effect of the atomic arrangement of the raw materials on zeolite crystallization behavior was investigated. It was also shown that the recrystallization behavior of amorphous solids back to zeolite is different in mechanically and post-mechanical thermally amorphized samples. This arises from the difference in the medium range order in the amorphous solids; that is, post-mechanical thermally amorphized samples were more able to change into dense phases since the ring structure of zeolite A was more distorted and/or destroyed than in only mechanically amorphized samples.

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The Frozen sorbet (FS) method is applied to the SrO–Al₂O₃–B₂O₃ system in order to fabricate glass ceramics consisting of Eu²⁺,Dy³⁺-doped SrAl₂O₄ phosphors, and their luminescent properties are examined. Through the quenching of melts (e.g., 55SrO–27Al₂O₃–18B₂O₃ with Eu₂O₃ and Dy₂O₃), composites (glass ceramics) consisting of the glass phase and SrAl₂O₄ crystals with a diameter of ∼40 µm are fabricated. It is found that SrAl₂O₄ crystals in the glass ceramics show excellent long persistent phosphorescent properties and improved excitation efficiency at ∼460 nm in the PL excitation spectra compared with SrAl₂O₄ phosphors prepared using a conventional solid state reaction. It is suggested that the Al³⁺-sites in SrAl₂O₄ crystals are partially substituted by B³⁺-ions. The present study proposes that the Frozen sorbet method can be a useful technique for the design of new SrAl₂O₄-based phosphor composites which can be used under white light emitting diode (LED) excitation (∼460 nm).

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Eu-doped yttria (Y_2−xEu_xO₃) thin-film phosphors were prepared using a sol–gel process with post-annealing at 900°C. The Y_2−xEu_xO₃ samples showed cubic bixbyite structure with a gradual increase in the lattice constant (≤0.5%) as x increases (≤0.22). The Eu-doped films exhibited strong photoluminescence (PL) near 2 eV at room temperature with well-resolved fluorescence peaks being ascribed to spin-flip f-f transitions, ⁵D₀ → ⁷F_J (J = 0, 1, 2, 3, 4, 6), within trivalent Eu³⁺(f⁶) ion. Among the six fluorescence lines, the intensity of the strongest 2.03-eV line (J = 2) varies significantly with the Eu content and its optimum value for the maximum PL strength is likely to be near x = 0.1. The Eu-doped films on the Al₂O₃ substrates exhibited significantly higher PL intensities than those on the Si substrates despite no significant difference in structural properties between the two species being observed. It can be understood by comparing the change of complex refractive index for the Y_2−xEu_xO₃/Al₂O₃ and Y_2−xEu_xO₃/Si optical systems.

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An α-Al₂O₃ bicrystal doped with Cr³⁺ was fabricated by diffusion bonding at high temperatures. It was found that a ruby phase with approximately 200 nm thickness was formed along the grain boundary. This thin phase shows Cr³⁺:Al₂O₃-induced luminescence, confirmed by confocal micro-luminescence spectroscopy.

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