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Ohyagi S.,Energy Research Inc. | Matsuda T.,Energy Research Inc. | Iseki Y.,KRI. Inc. | Sasaki T.,Energy Research Inc. | Kaito C.,Ritsumeikan University
Journal of Power Sources

In this study, we investigated the effects of humidity and oxygen reduction on the degradation of the catalyst of a polymer electrolyte membrane fuel cell (PEMFC) in a voltage cycling test. To elucidate the effect of humidity on the voltage cycling corrosion of a carbon-supported Pt catalyst with 3 nm Pt particles, voltage cycling tests based on 10,000 cycles were conducted using 100% relative humidity (RH) hydrogen as anode gas and nitrogen of varying humidities as cathode gas. The degradation rate of an electrochemical surface area (ECSA) was almost 50% under 189% RH nitrogen atmosphere and the Pt average particle diameter after 10,000 cycles under these conditions was about 2.3 times that of a particle of fresh catalyst because of the agglomeration of Pt particles. The oxygen reduction reaction (ORR) that facilitated Pt catalyst agglomeration when oxygen was employed as the cathode gas also demonstrated that Pt agglomeration was prominent in higher concentrations of oxygen. The ECSA degradation figure in 100% RH oxygen was similar to that in 189% RH nitrogen. It was concluded that liquid water, which was dropped under a supersaturated condition or generated by ORR, accelerated Pt agglomeration. In this paper, we suggest that the Pt agglomeration degradation occurs in a flooding area in a cell plane. © 2010 Elsevier B.V. All rights reserved. Source

Ikeda K.,Kyoto University | Kitagawa S.,Fuji Oil Co. | Tada T.,KRI. Inc. | Iefuji H.,Japanese National Research Institute of Brewing | Inoue Y.,Kyoto University
Applied Microbiology and Biotechnology

We have previously reported that the cultivation of yeast cells with soy peptides can improve the tolerance of yeast to freeze-thaw stress (Izawa et al. Appl Microbiol Biotechnol 75:533-538, 2007), indicating that soy peptides can modify the characteristics of yeast cells. To gain a greater understanding of the potencies of soy peptides, we further investigated the effects of cultivation with soy peptides on yeast physiology and found that soy peptides repress the formation of lipid bodies (also called lipid droplets or lipid particles), in which neutral lipids are accumulated. Compared with casein peptone, bacto peptone, yeast nitrogen base, and free amino acid mixtures having the same amino acid composition as soy peptides, cultivation with soy peptides caused decreased levels of mRNAs of neutral lipid synthesis-related genes, such as DGA1, and repressed the formation of lipid bodies and accumulation of triacylglycerol. These results indicate that soy peptides affect the lipid metabolism in yeast cells, and also demonstrate a potentiality of edible natural ingredients as modifiers of the characteristics of food microorganisms. © 2010 Springer-Verlag. Source

Hayashi H.,KRI. Inc. | Nakano H.,Ryukoku University
Journal of Alloys and Compounds

New red phosphors have been investigated in this study with europium as an activator added to Li1+x-yNb1-x-3yTix+4yO 3 (LNT) solid solutions with an M Phase superstructure. The photo-luminescence intensity of LNT:Eu solid solutions was dependent on the levels of both the Eu doping and the TiO2 content, and was superior to that of LiNbO3:Eu. LNT:Eu solid solutions with 2.5 wt.% Eu 2O3 showed the highest performance in this work, and maximum intensity was observed when the TiO2 content of LNT:Eu solid solutions was 10 mol.%. Structural analysis by XRD and HREM showed that in these new phosphors the M Phase superstructure was affected by the doping, with the periodicity of the superstructure becoming wider and more random. © 2010 Elsevier B.V. Source

Kri Inc. | Date: 2010-03-23

The present invention provides an organic/inorganic composite containing a rare earth metal or/and Period IV transition metal in which the aforementioned rare earth metal or/and Period IV transition metal is doped at a high concentration, and control of quenching and optical transparency are assured thereby; and an optical amplifier, a light control optical element, and luminescent device utilizing the same. The organic/inorganic composite containing a rare earth metal or/and Period IV transition metal is one in which at least one species of rare earth metal or/and Period IV transition metal is dispersed in an organic polymer, with the aforementioned composite containing an optically transparent organic polymer and an inorganic dispersion phase comprising: (1) a rare earth metal and (2) another element coordinated thereto via an oxygen atom(s). The inorganic dispersion phase in which another metal coordinates to rare earth metal or/and Period IV transition metal via an oxygen atom(s) preferably has an average particle size ranging from 0.1 to 1000 nm. Preferably, the ratio of rare earth metal or/and Period IV transition metal when mathematically converted to solid content is 90 mass % or less of the total mass of the organic polymer and the rare earth metal dispersion phase.

There is provided a solvent that can uniformly dissolve a polysaccharide within a short time period regardless of the crystal form of the polysaccharide and without requiring any special pretreatment. The solvent includes a tetraalkylammonium acetate represented by the below-indicated formula; and an aprotic polar solvent. A content of the aprotic polar solvent is 35 wt % or more. [Chem. 1] In the formula, R

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