Pulsed chemical vapour infiltration of TiN into a fine silica capillary sealed at one end

A fused-silica capillary sealed at one end of 1–100 m inner diameter was used as a substrate, and the thickness distribution of deposits on the inner wall was surveyed using pressurepulsed chemical vapour infiltration and the source gas system TiCl₄-N₂-H₂. All distribution curves had a minimum near the inlet, and had a maximum at a variable depth depending on the deposition temperature. The thickness ratioL(x)/L(out) (L(x) is the thickness of deposit at a depth ofx mm from the mouth, L(out) is the thickness on the outer wall of the capillary) varied with deposition temperature, inner diameter of the capillary, length of the capillary and so on. In the case of TiN infiltration, a temperature reduction to 850°C was effective to infiltrate to a deep zone.     

Synthesis and Application of Stable Copper Oxide Nanoparticle Suspensions for Nanoparticulate Film Fabrication

Colloidal suspensions of copper oxide (CuO) nanoparticles were prepared by an alcothermal method, in which copper acetate was reacted with sodium hydroxide in the presence of acetic acid in ethanol at 78°C. The prepared suspension was stable for up to 1 month without stabilizers such as surfactants. Transmission electron microscopy analyses revealed that the suspension contained nanosized CuO particles of 5–10 nm size with a narrow size distribution. Nanoparticulate CuO films packed with grains smaller than 60 nm were fabricated on Si substrates by spin coating a suspension of CuO nanoparticles and subsequent heat treatment at 500°C.     

Synthesis of novel photo-cross-linkable polymers with redissolution property

p-Styrenesulfonate derivatives having cycloaliphatic epoxide in a molecule, were synthesized. Oligomerization of the monomers and co-polymerization of the novel monomers with tert-butyl methacrylate were carried out. When the polymer films containing a photoacid generator (PAG) were irradiated, they became insoluble in solvents. The insoluble films became soluble in water on baking at 120-200 °C. The insolubilization and redissolution profiles were strongly affected by the structure of the monomer, irradiation and baking conditions, and a type of PAG used. The reaction mechanism was studied by TGA analysis and FT-IR spectroscopy.     

Sizes influences of weighing bar and vessel in the buoyancy weighing-bar method on floating particle size distribution measurements

To evaluate the influences of particle migration lengths as well as the sizes of the weighing bar and vessel on the particle size distribution measured by the buoyancy weighing-bar method, we experimentally measured the size distribution of hollow glass beads as floating particles. The buoyancy weighing-bar method, microscopy, and laser diffraction/scattering method give similar particle size distributions. The variation coefficient of the buoyancy weighing-bar method is close to the value determined by the laser diffraction/scattering method. Moreover, the accuracy of the buoyancy weighing-bar method is equal to that of the laser diffraction/scattering method. For vessels with identical sizes, the particle sizes measured by the buoyancy weighing-bar method increase when the weighing bar is too thick or too thin. Additionally, the influence of the weighing bar length on the particle size distribution is not confirmed in the case of the hollow glass beads. Thus, to effectively employ the buoyancy weighing-bar method, the sectional area ratio of the rod/vessel must be 0.02–0.2.     

Estimation of Δf of nitro derivatives of benzene and toluene using AM1 and DSC

Abstract

The AM1 molecular orbital method and reduced pressure differential scanning calorimetry(RP-DSC) were applied to nitro derivatives of benzene and toluene for estimating Δ_f(1) and Δ_f(c). The heats of phase change were determined by RP-DSC with moderate accuracy and the combination of the heats and Δ_f(g) estimated by AM1 gave Δ_f in condensed phases which are similar to those found in literatures.     

Preparation of Molybdenum, Vanadium, and Tungsten Oxide Thin Films from Self-Assembly Deposited Polyoxometalate–Alkylamine-Layered Hybrid Films

A novel, simple, and efficient route for preparing MoO₃, V₂O₅, and WO₃ films has been developed from layered polyoxometallate (POM)-alkylamine hybrid films by calcination. The highly ordered hybrid films were self-assembly deposited in a one-step process using clear precursor POM solutions, prepared by reacting layered MoO₃, V₂O₅, and WO₃·H₂O powders with hexylamine in the presence of water. The morphology of the resulting films can be tuned by removing the intercalated hexylamine molecules from the as-prepared hybrid films through UV irradiation before calcination.     

Novel photo-cross-linkable dendrimers having thermal de-cross-linking properties

Novel poly(aryl ether) type dendrimers having photo-cross-linking and thermal de-cross-linking properties were synthesized by a convergent method. A protected A₂B monomer, 1-allyloxy-3,5-bis(bromomethyl)benzene, was newly prepared for the dendrimer synthesis. Palladium-catalyzed deprotection of an allyl group proceeded in high yields. The films of dendrimers containing a photoacid generator (PAG) became insoluble in solvents on irradiation. The irradiated films became soluble in solvents after baking at 120-200 °C. The insolubilization and redissolution profiles were strongly affected by irradiation and baking conditions and the generation of the dendrimers. A reaction pathway was studied by TGA and DTA analysis and FT-IR spectroscopy.     

First-Principles Study of Semiconducting Clathrate Ba<Subscript>8</Subscript>Al<Subscript>16</Subscript>Ge<Subscript>30</Subscript>

We calculated electronic structures of Ba₈Al₁₆Ge₃₀ in some Al-Ge framework configurations without nearest-neighbor Al-Al bonds by using a first-principles method. The calculated band structures are similar in outline but different in detail. We also calculated thermoelectric properties by using the electronic structures to analyze the experimental results on a sintered Ba₈Al₁₆Ge₃₀ sample. The calculated properties nearly agree with the experimental results; however, the calculated temperature dependences of electrical conductivity are slightly different from one another, because of differences in electronic structure. In this paper, we discuss the temperature dependence from the viewpoints of nonparabolic band effects.     

Spatial Distribution of the Seebeck Coefficient in Zn<Subscript>13</Subscript>Sb<Subscript>10</Subscript> Determined by a Seebeck Microprobe Measurement System

A Seebeck microprobe (SMP) measurement system has been developed and employed to determine the spatial distribution of the Seebeck coefficient of a polycrystalline Zn₁₃Sb₁₀ specimen prepared by a gradient freeze (GF) method. The spatial distribution of the Seebeck coefficient strongly reflects that of the grains observed using an optical polarizing microscope, the magnitude of which ranges from 100 μV/K to 130 μV/K. This fact strongly indicates that the observed spatial distribution of the Seebeck coefficient arises from the anisotropic Seebeck effect of grains with different crystal orientations in the polycrystalline Zn₁₃Sb₁₀.