Journal of the Physical Society of Japan, Aug 15, 1993
Optical properties of fcc C 60 samples have been studied by using photoacoustic spectroscopy over... more Optical properties of fcc C 60 samples have been studied by using photoacoustic spectroscopy over the temperature range 30–300 K. A sharp absorption edge is seen at 1.7 eV at room temperature. The optical absorption spectrum changes drastically at 80 K. Another change of absorption spectrum is also observed at 260 K. These changes can be explained by the molecular motion of C 60 .
Photoacoustic spectroscopy measurements have been carried out on the Se-ring microclusters confin... more Photoacoustic spectroscopy measurements have been carried out on the Se-ring microclusters confined in the cages of zeolite 4A. The shift of photoabsorption edge and the new absorption bands around 1.5 and 1.9 eV appeared by illumination of the light having the band-gap energy at low temperature. These phenomena may be associated with the distortion of Se ring and the formation of dangling bonds. Mixing of S or Te to the Se microclusters causes appreciable change in the photoinduced phenomena.
This is a collection of selected, peer reviewed papers from the International Conference on Nanom... more This is a collection of selected, peer reviewed papers from the International Conference on Nanomaterials: Science, Technology and Applications (ICM' 13), December 5-7, 2013, Chennai, India. The 54 papers are grouped as follows: Nano Materials: Synthesis and Characterisation, Electrical, Magnetic, Optical Properties of Nanomaterials, Polymers and Nanocomposites, Bio Nanomaterials and their Applications, Nanomaterials: Energy & Environment, and, Nanomaterials: Theoretical and Computational Studies.
... for chalcogen Correspondence to: Professor H. Endo, Department of Physics, Faculty of Science... more ... for chalcogen Correspondence to: Professor H. Endo, Department of Physics, Faculty of Science, Kyoto University, Oiwake-cho, Kitasira: kawa, Sakyo-cho ... A theoretical study by Ikawa and Fukutome has revealed that, near the chain end, chalcogen chains tend to have a planar ...
EXAFS measurements have been carried out on Se K-edge and Te K-edge for Se8-x Te x and Se8-x S x ... more EXAFS measurements have been carried out on Se K-edge and Te K-edge for Se8-x Te x and Se8-x S x microclusters with 8 chalcogen atoms. The clusters with various compositions were isolated in a synthetic 4A zeolite which has 11Å-diameter cage units. The data analysis led us to believe that the clusters form 8-membered rings in the cage. In Se8-x Te x microclusters, Se–Se bonds and Te–Te bonds are shorter than those in the crystalline state. It is found that Se–Te unlike-pairs are preferred over Se–Se and Te–Te like pairs. On the other hand, in Se8-x S x microclusters, Se–Se and S–S like-pairs are found to be preferred over Se–S unlike-pairs.
Ce0.80Pr0.12Sn0.08O2−δ combination catalyst exhibited highest CO oxidation activity owing to its ... more Ce0.80Pr0.12Sn0.08O2−δ combination catalyst exhibited highest CO oxidation activity owing to its high specific surface area, better reducibility, superior surface active oxygen species, and oxygen vacancies among various samples investigated.
The authors maintain a culture collection of over 2,500 cyanobacteria and photosynthetic bacteria... more The authors maintain a culture collection of over 2,500 cyanobacteria and photosynthetic bacteria and 2,000 eukaryotic algae for research on H{sub 2} biophotoproduction as well as other projects. A high H{sub 2}-producing strain Synechococcus sp. Miami BG 043511 from the collection has been used to examine H{sub 2} production in relation to water photolysis and substance degradation, high O{sub 2}-tolerance characterization of nitrogenase, and interactive effects of light intensity and cell density on H{sub 2} production and its stable isotope fractionation. When cellular carbohydrate is depleted, no H{sub 2} production occurs. However, when pyruvate or glucose is added, H{sub 2} production begins. On the other hand, when glucose and DCMU are added to cellular carbohydrate-depleted cells from synchronous cultures, H{sub 2} production is inhibited compared with that with glucose addition alone. These results indicate that water photolysis alone cannot directly induce H{sub 2} product...
To develop efficient materials for CO oxidation, a series of co-doped CeO₂ ternary oxide solid so... more To develop efficient materials for CO oxidation, a series of co-doped CeO₂ ternary oxide solid solutions (Ce₀.₈₀M₀.₁₂Sn₀.₀₈O₂₋δ, M = Hf, Zr, Pr, and La) were prepared by a simple coprecipitation method. The fundamental characteristics of the co-doped CeO₂ samples were studied by X-ray diffraction, Raman spectroscopy, UV-visible diffuse reflectance spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller surface area, H₂-temperature programmed reduction, X-ray photoelectron spectroscopy, and O₂-temperature programmed desorption. The oxidation of CO was chosen as a model reaction to evaluate the catalytic performance of these samples. The characterization results revealed that ternary oxide solid solutions had significantly enhanced surface area, improved reducibility, increased oxygen mobility and higher quantity of surface adsorbed oxygen species and oxygen vacancies, compared to undoped CeO₂. The CO oxidation performance of CeO₂ was greatly improved upon co-doping due...
Journal of the Physical Society of Japan, Aug 15, 1993
Optical properties of fcc C 60 samples have been studied by using photoacoustic spectroscopy over... more Optical properties of fcc C 60 samples have been studied by using photoacoustic spectroscopy over the temperature range 30–300 K. A sharp absorption edge is seen at 1.7 eV at room temperature. The optical absorption spectrum changes drastically at 80 K. Another change of absorption spectrum is also observed at 260 K. These changes can be explained by the molecular motion of C 60 .
Photoacoustic spectroscopy measurements have been carried out on the Se-ring microclusters confin... more Photoacoustic spectroscopy measurements have been carried out on the Se-ring microclusters confined in the cages of zeolite 4A. The shift of photoabsorption edge and the new absorption bands around 1.5 and 1.9 eV appeared by illumination of the light having the band-gap energy at low temperature. These phenomena may be associated with the distortion of Se ring and the formation of dangling bonds. Mixing of S or Te to the Se microclusters causes appreciable change in the photoinduced phenomena.
This is a collection of selected, peer reviewed papers from the International Conference on Nanom... more This is a collection of selected, peer reviewed papers from the International Conference on Nanomaterials: Science, Technology and Applications (ICM' 13), December 5-7, 2013, Chennai, India. The 54 papers are grouped as follows: Nano Materials: Synthesis and Characterisation, Electrical, Magnetic, Optical Properties of Nanomaterials, Polymers and Nanocomposites, Bio Nanomaterials and their Applications, Nanomaterials: Energy & Environment, and, Nanomaterials: Theoretical and Computational Studies.
... for chalcogen Correspondence to: Professor H. Endo, Department of Physics, Faculty of Science... more ... for chalcogen Correspondence to: Professor H. Endo, Department of Physics, Faculty of Science, Kyoto University, Oiwake-cho, Kitasira: kawa, Sakyo-cho ... A theoretical study by Ikawa and Fukutome has revealed that, near the chain end, chalcogen chains tend to have a planar ...
EXAFS measurements have been carried out on Se K-edge and Te K-edge for Se8-x Te x and Se8-x S x ... more EXAFS measurements have been carried out on Se K-edge and Te K-edge for Se8-x Te x and Se8-x S x microclusters with 8 chalcogen atoms. The clusters with various compositions were isolated in a synthetic 4A zeolite which has 11Å-diameter cage units. The data analysis led us to believe that the clusters form 8-membered rings in the cage. In Se8-x Te x microclusters, Se–Se bonds and Te–Te bonds are shorter than those in the crystalline state. It is found that Se–Te unlike-pairs are preferred over Se–Se and Te–Te like pairs. On the other hand, in Se8-x S x microclusters, Se–Se and S–S like-pairs are found to be preferred over Se–S unlike-pairs.
Ce0.80Pr0.12Sn0.08O2−δ combination catalyst exhibited highest CO oxidation activity owing to its ... more Ce0.80Pr0.12Sn0.08O2−δ combination catalyst exhibited highest CO oxidation activity owing to its high specific surface area, better reducibility, superior surface active oxygen species, and oxygen vacancies among various samples investigated.
The authors maintain a culture collection of over 2,500 cyanobacteria and photosynthetic bacteria... more The authors maintain a culture collection of over 2,500 cyanobacteria and photosynthetic bacteria and 2,000 eukaryotic algae for research on H{sub 2} biophotoproduction as well as other projects. A high H{sub 2}-producing strain Synechococcus sp. Miami BG 043511 from the collection has been used to examine H{sub 2} production in relation to water photolysis and substance degradation, high O{sub 2}-tolerance characterization of nitrogenase, and interactive effects of light intensity and cell density on H{sub 2} production and its stable isotope fractionation. When cellular carbohydrate is depleted, no H{sub 2} production occurs. However, when pyruvate or glucose is added, H{sub 2} production begins. On the other hand, when glucose and DCMU are added to cellular carbohydrate-depleted cells from synchronous cultures, H{sub 2} production is inhibited compared with that with glucose addition alone. These results indicate that water photolysis alone cannot directly induce H{sub 2} product...
To develop efficient materials for CO oxidation, a series of co-doped CeO₂ ternary oxide solid so... more To develop efficient materials for CO oxidation, a series of co-doped CeO₂ ternary oxide solid solutions (Ce₀.₈₀M₀.₁₂Sn₀.₀₈O₂₋δ, M = Hf, Zr, Pr, and La) were prepared by a simple coprecipitation method. The fundamental characteristics of the co-doped CeO₂ samples were studied by X-ray diffraction, Raman spectroscopy, UV-visible diffuse reflectance spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller surface area, H₂-temperature programmed reduction, X-ray photoelectron spectroscopy, and O₂-temperature programmed desorption. The oxidation of CO was chosen as a model reaction to evaluate the catalytic performance of these samples. The characterization results revealed that ternary oxide solid solutions had significantly enhanced surface area, improved reducibility, increased oxygen mobility and higher quantity of surface adsorbed oxygen species and oxygen vacancies, compared to undoped CeO₂. The CO oxidation performance of CeO₂ was greatly improved upon co-doping due...
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