著者
青峰 隆文 西嵜 照和 山本 高広
出版者
Japan Society of Powder and Powder Metallurgy
雑誌
粉体および粉末冶金 (ISSN:05328799)
巻号頁・発行日
vol.37, no.1, pp.114-117, 1990

It is known that sintered bulk samples of high Tc superconducting oxides have low critical current density and show hysteresis of critical currents in low magnetic fields. These phenomena are attributed to weak links at a grain boundary. In this work we report on the hysteresis of sintered bulk samples of high Tc superconducting oxides and of superconducting, relatively long bridges which have a constricted part made artificially. The former hysteresis is found to be very similar to the latter one. We consider that the hysteresis of sintered bulk samples of high Tc superconducting oxides occurs for the existence of superconducting, relatively long bridges and trapped flux in them.
著者
江藤 博文 山本 高広 新井 康平
出版者
Japan Society of Photogrammetry and Remote Sensing
雑誌
写真測量とリモートセンシング (ISSN:02855844)
巻号頁・発行日
vol.39, no.3, pp.14-20, 2000

A method for Earth observation satellite image database retrieve based on indexing of the spatial features extracted from the imagery data is proposed. In order to extract edges from the imagery data, the well known relaxation method and the thining algorithm are used. From the edges, spatial features, line, arc as well as circle are extracted. The proposed method is compared to the generalized Hough conversion method. It is found that the proposed method allows to extract arbitrary spatial features intentionally while the generalized Hough conversion method does not because the control parameters of the method is not enough. It is also found that the required computer resources are almost compatible. Using such spatial features, the portion of images with such features are retrieved from the imagery data.
著者
若杉 三紀夫 山本 高広
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.40, no.457, pp.1372-1378, 1991-10-15

The effects of three types of polymer modification on both hydration characteristics and physical properties of the gypsum pastes and mortars originated from anhydrite plaster have been studied at various polymer-gypsum ratios. The polymer dispersions used were ethylene-vinyl acetate (EVA), polyacrylic ester and styrene-butadiene rubber. The degree of hydration of the gypsum pastes and mortars was examined by X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and porosity measurement. The setting time of fresh gypsum mortars (polymer-modified and unmodified) as well as the physical properties of hardened gypsum mortars were also measured. The hydration was complete in about 3 days, and the degree of hydration of the polymer-modified gypsum mortars was smaller than that of unmodified mortar. The setting time of gypsum mortars was retarded by the addition of polymer, and was affected by the chemical structure of polymer. The flexural and tensile strengths of the EVA-modified mortar with a polymer-gypsum ratio of 5% were higher than those of unmodified mortar. Its elastic modulus was the smallest of all, and further EVA-modified mortars showed small linear expansion. From the above test results, the EVA-modified gypsum mortar with a polymer-gypsum ratio of 5% was shown to be one of the candidates of the better plastering materials for polystyrene and polyurethane foams.