Hiroyuki Shinoda

Influence of basic color categories on color memory discrimination.

Two color-memory experiments were performed to investigate whether observers tended to confuse colors with a smaller color difference in memory or colors in a same color-category region. We made color stimuli on a color CRT. Color difference was determined by a simultaneous color discrimination experiment. Color-category regions were obtained by a categorical color-naming experiment using the 11 basic color names: white, black, red, green, yellow, blue, brown, orange, purple, pink, and gray. The results show that two colors with a certain color difference can be confused more easily when they are in a same color category than in different color categories, and that colors identified with memory tend to distribute within their own color-category regions or their neighbor color-category regions, depending on their positions in a color space. These findings indicate that color memory is characterized by the color categories, suggesting a color-category mechanism in a higher level of color vision.

Photocatalytic and photoelectrochemical propertiesof TiO2-based multiple layer thin film prepared by sol–geland reactive-sputtering methods

The multiple layers of a TiO2 thin film, consisting nof a TiO2 thin film, a platinum electrode and a porous alumina nsubstrate, were prepared by the sol–gel method in a previous study. nAs a sputtering process has some advantages over wet-chemical processes, especially nfor practical manufacturing, a thin film photocatalyst with the same layer nstructure was prepared by the reactive-sputtering method in this study. The nTiO2 thin film of the photoactive anatase phase was formed by using nan appropriate gas pressure and temperature, however, the crystallite size nof anatase was almost twice as large and the band gap energy was slightly nsmaller than those of the sol–gel-processed thin film. The sputtering-processed nthin film showed a typical columnar structure with some voids. The lower band ngap energy and the coarse structure probably promoted the recombination between nphotoexcited electrons and holes, and resulted in lower photocatalytic activity nand photocurrent compared with the sol–gel-processed thin film.