Heat Capacity Measurement of Oxygen-Dissolved V–Ti Alloys1

The heat capacities of (V_1–y Ti _y ) O _x alloys (x=0.13 to 0.18, y=0.06 to 0.23) were measured in the temperature range from 380 to 900K with a differential scanning calorimeter. A -type peak corresponding to the order–disorder phase transition was observed in the heat capacity curves of each (V_1–y Ti _y ) O _x alloy (x0.18, y0.09). The baseline of the measured heat capacity was estimated with the harmonic term and the anharmonic term of the lattice vibration. The entropy changes at the phase transition were determined by subtracting the baseline mentioned above from the measured heat capacities. The experimental entropy changes were in good agreement with those calculated theoretically, based on the arrangement of oxygen and the limited coordination number of oxygen around vanadium. There were no peaks in the heat capacity curves for the samples with compositions y0.16. Introduction of titanium, which has a larger ionic radius than that of vanadium, may disturb the ordering of oxygen around the metal.     

Electronic nature of vanadium nitride-carbon cluster composite materials obtained by the calcination of oxovanadylphthalocyanine

Calcination of oxovanadylphthalocyanine at 500-1000 °C under an argon atmosphere was performed. Elemental analyses, XRD and TEM measurements revealed that the calcined materials are composed of nano-sized vanadium nitride and carbon clusters. ESR spectral examinations suggested that the calcined materials have a photo-responsive charge separation feature. The decomposition of methylene blue and trimethylhydroquinone in the presence of the material calcined at 900 °C was accelerated by visible light irradiation. H₂ evolution was detected from a mixture of the calcined material and water under the visible light irradiation.     

ArchaeoSTOR: A data curation system for research on the archeological frontier

The broad adoption of diagnostic and analytical techniques in the field of archeology, presents a unique opportunity for e-Science in the form of scientific explanation, drawing from methodologies aimed at recording, archiving, analyzing, and disseminating, rich data collections to create the needed infrastructure for both research and web-based curation and data management system. This paper presents a needed stepping stone towards synergy between information technology and archeology, by introducing a data acquisition, tagging and characterization pipeline along with a novel method for spatially querying archeological data.     

Sintering Kinetics at Isothermal Shrinkage: Effect of Specific Surface Area on the Initial Sintering Stage of Fine Zirconia Powder

The isothermal shrinkage behaviors of fine zirconia powders (containing 2.8–2.9 mol% Y₂O₃) with specific surface areas of about 6 and 16 m²/g were investigated to clarify the effect of specific surface area on the initial sintering stage. The shrinkage of powder compact was measured under constant temperatures in the range of 1000°–1100°C. The increase in specific surface area enhanced the densification rate with increasing temperature. The values of activation energy ( Q ) and frequency-factor term (β₀) of diffusion at initial sintering were estimated by applying the sintering-rate equation to the isothermal shrinkage data. The Q of diffusion changes little but the β₀ increases with the increase in specific surface area. It is therefore concluded that the increase in the specific surface area of fine zirconia powder enhances the shrinkage rate because of an increase in the β₀ at the initial stage of sintering.     

Coping with nonstationary environments: a genetic algorithm using neutral variation

In nonstationary environments, it is difficult to apply traditional genetic algorithms (GAs) because they use strong selection pressure and lose the diversity of individuals rapidly. We propose a GA with neutral variation that can track environmental changes. The idea of this GA is inspired by Kimura's neutral theory (1983). The scheme of this GA allows neutral characters, which do not directly affect the fitness with respect to environments, thus increasing the diversity of individuals. In order to demonstrate the properties of this GA, we apply it to a permutation problem called the ladder-network, of which the imposed alignment on the output changes regularly. We show that the GA with neutral variation can adapt better to environmental changes than a traditional GA.     

Syntheses and Electronic Behaviors of Networked Alternating Aluminum-organic Moiety Hybrid Copolymers

Hybrid copolymers with aluminum-organic moiety frameworks were successfully prepared by reacting aluminum tri-sec-butoxide with several organic diols. The compositions of the resulting copolymers were determined using IR spectroscopy, ICP, elemental analysis and CP/MASS ¹³C-NMR spectroscopy. The UV-VIS spectra of the copolymers were also obtained. ESR spectral examinations of the copolymers and ab-initio calculations of the copolymer models indicate that an electron transfer takes place from the organic moiety to the aluminum atom in the framework.     

Denture base materials reinforced with glass fibres

Glass fibres for industrial use were laid on denture base materials such as self-curing and heat-curing resins to reinforce them. The use of heat-curing rather than self-curing resin as a base resin indicated a superior effect on bending properties.     

Connection of VLSI chips to printed circuit board using stacked solder bumps

A new type of flip-chip interconnection technology usingstacked solder bumps is proposed, where the diameter of theupper solder bump is less than that of the lower ones. This isto reduce the capacitance between the stacked solder bumps and the ground plane and to prolong the lifetime ofthe solder joints.