In situ formation of catalytically active graphene in ethylene photo-epoxidation.

Ethylene epoxidation is used to produce 2 × 107 ton per year of ethylene oxide, a major feedstock for commodity chemicals and plastics. While high pressures and temperatures are required for the reaction, plasmonic photoexcitation of the Ag catalyst enables epoxidation at near-ambient conditions. Here, we use surface-enhanced Raman scattering to monitor the plasmon excitation-assisted reaction on individual sites of a Ag nanoparticle catalyst. We uncover an unconventional mechanism, wherein the primary step is the photosynthesis of graphene on the Ag surface. Epoxidation of ethylene is then promoted by this photogenerated graphene. Density functional theory simulations point to edge defects on the graphene as the sites for epoxidation. Guided by this insight, we synthesize a composite graphene/Ag/α-Al2O3 catalyst, which accomplishes ethylene photo-epoxidation under ambient conditions at which the conventional Ag/α-Al2O3 catalyst shows negligible activity. Our finding of in situ photogeneration of catalytically active graphene may apply to other photocatalytic hydrocarbon transformations

駅空間の総合的な評価を通した照明設計方法に関する研究

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 平手 小太郎, 東京大学教授 赤司 泰義, 東京大学准教授 前 真之, 東京大学准教授 松田 雄二, 実践女子大学教授 槇 究University of Tokyo(東京大学

Characterization of Ceramicrete Waste Form for Disposal of Concrete Waste of Decommissioned Nuclear Power Plant

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붕규산 유리에서 MoO3의 용해도에 대한 MnO의 영향

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A Study on the Comparison of Impressions of Tourist Information Signs Focusing on the Differences between National Languages in Japanese Regional Cities

From the perspective of universal design, signs should be easy to understand for all users. In Japan, tourist information signs have become increasingly multilingual in recent years as the number of tourists from other countries has increased. However, it is not clear whether the current signs are comprehensible to both Japanese and non-Japanese speakers. In this study, field and questionnaire surveys on signs were conducted in Matsue City, a regional city in Japan, and the evaluations of Japanese and non-Japanese speakers were compared. In the field survey, a caption evaluation method was used to evaluate the visual environment, and in the questionnaire survey, the SD method was used to evaluate the signs obtained in the field survey. The results indicated that non-Japanese speakers were more likely to focus on signs, and signs with diagrams and maps were evaluated more positively. In addition, the evaluation structure of signs was found to consist of four elements: “Harmonicity”, “Clarity”, “Visibility”, and “Comprehensibility”. “Harmonicity” was indicated to be as important as “Clarity” and “Visibility”. These results suggest that the replacement of text with diagrams on signs contributes to the improvement of impressions and is particularly effective for non-Japanese speakers

A Study on the Comparison of Impressions of Tourist Information Signs Focusing on the Differences between National Languages in Japanese Regional Cities

From the perspective of universal design, signs should be easy to understand for all users. In Japan, tourist information signs have become increasingly multilingual in recent years as the number of tourists from other countries has increased. However, it is not clear whether the current signs are comprehensible to both Japanese and non-Japanese speakers. In this study, field and questionnaire surveys on signs were conducted in Matsue City, a regional city in Japan, and the evaluations of Japanese and non-Japanese speakers were compared. In the field survey, a caption evaluation method was used to evaluate the visual environment, and in the questionnaire survey, the SD method was used to evaluate the signs obtained in the field survey. The results indicated that non-Japanese speakers were more likely to focus on signs, and signs with diagrams and maps were evaluated more positively. In addition, the evaluation structure of signs was found to consist of four elements: “Harmonicity”, “Clarity”, “Visibility”, and “Comprehensibility”. “Harmonicity” was indicated to be as important as “Clarity” and “Visibility”. These results suggest that the replacement of text with diagrams on signs contributes to the improvement of impressions and is particularly effective for non-Japanese speakers

Solidification of concrete wastes from decommissioning of nuclear power plants with magnesium phosphate cements

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Effect of ZnO as Retardant of Magnesium Phosphate Cement to Solidify Radioactive Waste

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