A novel catalyst fabricated from Al–Cu–Fe quasicrystal for steam reforming of methanol

The optimum preparation condition of Al–Cu–Fe quasicrystalline (QC) catalyst with excellent catalytic performance for steam reforming of methanol (SRM) has been investigated. The QC alloy is superior to the other crystalline Al–Cu–(Fe) alloys (i.e., beta and theta phase) as a catalyst material because of the brittle nature of QC. The wet milling process (in ethanol) for the QC powders is much better than the dry milling process to obtain fine particles with high surface area. The QC powder prepared by the wet process followed by leaching in Na₂CO₃ aq. at 323 K exhibited the highest catalytic performance (activity and stability) in the present study. From these findings, it is clear that the QC catalyst with the excellent catalytic performance could be obtained by controlling the initial grain size of the QC powder and the leaching temperature.     

Hall effect of photocurrent in CVD diamond film

Transient Hall voltage of photocurrent excited by the modulated light with photon energies near bandgap is observed in undoped and B-doped CVD diamond films. It is seen that photo-carriers created in the films by the band-to-band excitation higher than 5.5 eV are almost holes and the contribution of electrons is about 7% in the undoped film and 0% in the B-doped film. Photo-carriers excited by the light with photon energies 4.7 to 5.5 eV, in which the step-like absorption band is observed, are holes, which agrees with the result of the temperature dependence of the photocurrent excited by the light with the photon energies.     

Enhancement of resolution and linearity control of contact-holeresist patterns with surface-active developer

The resolution enhancement of contact-hole resist patterns featuring precise linear correlation between mask size and resist-pattern size by employing a surface-active developer is presented. The addition of surfactant improves the wettability of the developer, thus enabling the solution to penetrate narrow spaces. The optimum surfactant concentration in developer leads to superior resist performance. This technology for contact-hole patterning results in high resolution, high sensitivity, and a wide process margin for ULSI manufacturing     

Energy transfer and trap site formation in a photopolymer film containing carboxyl groups and benzylidene ketone dyes

The photophysics of the hydrogen-bonded (HB) state and the protonated (PR) state of a photosensitizer, 2,6-bis(4′-diethylaminobenzylidene)cyclopentanone (DBC) in a polymer matrix containing carboxyl groups was investigated by fluorescence spectroscopy and decay curve analysis. The fluorescence spectrum of the excited DBC HB with the carboxyl unit was composed of emission from two species peaking at 567 and 627 nm, which were assigned to the emission from the weakly HB state (HB1) and the strongly HB state (HB2) of DBC, respectively. The excitation energy is able to migrate through the HB1 states and then transfers to the HB2 site and the PR DBC site. At low DBC concentrations, not only PR but also HB2 acts as a deep trap of the excitation energy. The concentration of PR was estimated to be ca. 40% of DBC by the fluorescence decay analysis based on the Förster kinetics. These results indicate that the photoinitiation reaction of this photopolymer system proceeds in competition with the energy transfer to these large amounts of trap sites formed by interaction between the DBC dye and the carboxyl unit of the matrix polymer.     

PREDICTION AND EVALUATION OF LONG-TERM CREEP-FATIGUE LIFE

Ordinary short-term creep fatigue tests were carried out on a servo-hydraulic testing machine for various heat resistant steels. From these results a life prediction method in the long-term creep-fatigue regime is proposed using creep rupture ductility data up to 10⁵ h. To verify the predicted life the authors have developed a new type of testing machine driven by thermo-actuator which can evaluate the long-term creep-fatigue behaviour of materials beyond 10⁴ h.     

Synthesis of Cubic Boron Nitride by Decomposition of Magnesium Boron Nitride

Cubic boron nitride ( c -BN) was synthesized by the decomposition of Mg₃BN₃ under high pressure and high temperature. The minimum pressure for c -BN synthesis was 4 GPa, which was 1 GPa lower than that of the conventional catalytic process. The decomposition of Mg₃BN₃ was observed only when H₂O was added. Therefore, the reaction was as follows: Mg₃BN₃+ 3H₂O = 3MgO + c -BN + 2NH₃. The c -BN crystals obtained were tetrahedron in shape and about 10 μ m in diameter.     

Analysis of cationic and amphoteric surfactants: III. Structural analysis of imidazolinium cationic surfactants

Determination of the homologous distribution of imidazolinium cationic surfactants and their structural analysis have been inves-tigated. These surfactants were hydrolyzed under aqueous alkaline media, followed by acid hydrolysis to afford fatty acids and poly-amines. The resulting fatty acids were esterified with methanol, and then analyzed by gas chromatography (GC) in order to determine their homologous distribution. The obtained distribution agrees well with that of original fatty acid. Therefore, this method should be applicable to the determination of the homologous distribution of imidazolinium surfactants. The resulting polyamines were acetylated with acetic anhydride in the presence of pyridine. These acetates were analyzed by GC and isolated by preparative thin layer chroma-tography on silica gel. The structures of these isolates were identi-fied by means of 1 H-NMR and 1R spectrometry. These structural analyses demonstrated that quaternization of an imidazoline ring selectively occurred at the nitrogen at the 3-position of an imida-zoline ring, which was the kinetically favored position in terms of the steric hinderence and the stability of product.     

Synthesis of Heterocycle-Containing [60]Fullerene Derivatives

Fullerene functionalization with heterocycles is reviewed, focusing attention on cycloaddition methodology and oxidative heterocyclization.¹