Physicochemical states of vanadium in V-doped SnO, were studied to clarify the origin of the color of vanadium-tin yellow pigment and its color instability when fired with glaze material. Precision measurements of lattice parameters of V-doped SnO, revealed that vanadium was dissolved as V4' and its solubility limit was 0.9 wt% as Vz05. It was found that the color of vanadium-tin yellow was produced by two types of undissolved vanadium on SnO, grains. One is poorly crystallized vandium oxide (v), (Vz05)', having a yellow color, and the other is orange-colored crystalline V,05. The structure of (V,O,)' was discussed in connection with its color.

The CoAl 2 O 4 pigment commonly used for coloring ceramic products was synthesized by microwave hydrothermal processing (M-H), and ink-jet printing with this aqueous pigment ink was performed to decorate porcelain. First, a precursor was prepared by adjusting the solution to pH 12. Then, M-H reaction was applied to this precursor at 240°C for 2 h, yielding particles of CoAl 2 O 4 . In addition, the precursor concentration of the suspension was shown to greatly affect the color tone of the resulting particles. As the precursor concentration increased, the synthesized particles that were bluish-green at lower concentrations took on a darker blue color. The synthesized CoAl 2 O 4 particles were regular octahedrons measuring approximately 70 nm. The particles synthesized by M-H reaction were used to prepare an aqueous suspension, which was then used for printing on tiles by an ink-jet printing system. The synthesized particles were well dispersed in the prepared aqueous suspension, as little sediment was formed in this suspension left for 1 week. The printing system experienced no clogging and the printed image was of good quality.

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Air-bridge-structured Si wires were fabricated by using a silicon-on-insulator (SOI) substrate and electrically characterized. The SOI substrate used had a sandwich structure of a 200-nm-thick p-type Si layer (SOI layer), a 400-nm-thick buried oxide layer (BOX layer) and a p-type Si substrate. The wires were made by conventional photolithography process followed by dry etching and thermal oxidation thinning of the SOI layer. The Si wires were isolated from the substrate by an air gap made in the BOX layer and had dimensions of typically 20 nm in width, 40 nm in height and 150 nm in length. It was found from the measurements of current-voltage characteristics that the current through the wires much increased by illumination with a He-Ne laser and reached about 20 nA at a bias of 1 V.

We are developing functionally graded grinding wheels fabricated by a centrifugal mixed-powder method. As a first step of this fabrication method, a powder mixture of abrasive particles and metal matrix particles is inserted into a spinning mould. After that, a metal matrix ingot is melted and then the molten metal matrix is poured into the spinning mould with the powder mixture. As a result, the molten metal matrix penetrates into the space between the particles due to the pressure exerted by the centrifugal force. At the same time, the metal matrix powder is melted by the heat from molten matrix poured from the crucible. Finally, a ring-shaped sample with abrasive particles distributed on its surface (functionally graded grinding wheel) can be obtained. In this study, functionally graded grinding wheel fabricated by the centrifugal mixed-powder method will be reported. 2011) 'Fabrication of functionally graded grinding wheel by a centrifugal mixed-powder method for CFRP-drilling applications', Int.