A nanoparticle catalyst of PtRuAu/C was synthesized by including an Au precursor in the radiolytic process for preparing a PtRu/C catalyst. Their methanol oxidation activity and electrochemical durability were measured by linear sweep voltammetry before and after potential cycling treatment. PtRuAu/C had a significantly higher durability than PtRu/C while maintaining a comparable high activity. The morphology and substructure of the nanoparticles were investigated by energy-dispersive x-ray spectroscopy, x-ray diffraction, and x-ray absorption fine structure spectroscopy. Metallic nanoparticles with diameters of about 2 nm were obtained; they probably had Pt-core/PtRu-shell structures. Transmission electron microscopy observations after potential cycling revealed that 2-nm-diameter nanoparticles containing Au did not coarsen, whereas nanoparticles without Au coarsened significantly to 3.7 nm. Some crystal defaults were observed in the coarsened particles, implying that the coarsening was caused by Ostwald ripening. The Au addition to catalyst particles consisting of PtRu inhibits coarsening and consequently improves the electrochemical durability.

Nanoparticle catalyst of PtRuAu/C for direct methanol fuel cell anodes was synthesized by a radiolytic process. Its methanol oxidation activity and the electrochemical durability were evaluated by using the linear sweep voltammetry and the cyclic voltammety. The Au addition significantly improved the durability in comparison with PtRu/C catalyst without losing its high activity. The atomic structure was characterized with techniques of the transmission electron microscopy, the X-ray diffraction, the X-ray fluorescence spectroscopy and the X-ray absorption fine structure. These results implied that the arrangement of Pt and Ru atoms in the PtRuAu/C has no significant difference from that without Au, possessing a structure of Pt rich core and PtRu alloy shell. We concluded that the improvement in durability could originate from these PtRu nanoparticles decorated with Au, but not from particles with high Au contents.

Bright green auto-fluorescence was observed in the umbrellar margin, umbrellar marginal warts, tentacular bulbs, tentacles, and manubrium of laboratory-reared immature (1–14 days old) medusae of Eutima japonica from Japan and China. In vivo microscopic fluorescence spectra showed that the green fluorescence was similar to that of green fluorescent protein (GFP) found in Aequorea victoria, although the maximum emission wavelength (503 nm) was slightly bluer. No fluorescence was detected in the cirri, statocysts, radial canals, velum, or subumbrella of the medusae. The fluorescence distribution pattern in E. japonica more closely resembles that of Eugymnanthea inquilina from the Mediterranean Sea than that of Japanese Eugymnanthea japonica, which is the derived species of E. japonica. This suggests that the common fluorescence pattern is convergently evolved in the former two species, perhaps owing to the as yet unclarified physiological and/or ecological function of GFP and/or GFP-like proteins.

Selective-area MBE growth of Si1−xGex film is examined using a Si substrate partially covered with SiO2 film. Elimination of misfit dislocations is observed by TEM. Two possible mechanisms in this elimination, limitation of the lateral extension of misfit dislocations, and partial relaxation of the strain at the SiO2 pattern edge, are discussed.

Electrical characteristics of modulation-doped p-Si0.5Ge0.5/Ge/Si1−x Gex heterostructures are examined in relation to Si fraction (1−X) and thickness (dB)of the buffer layer (Si1−xGex), using Raman spectroscopy and transmission electron microscopy. Strain-induced enhancement of hole mobility and concentration is observed in 1-X≦0.25. However, their decrease in 1-X≦0.25 and for small dB values is also observed, which is attributed to the increase in threading dislocations. As a result, a maximum hole mobility of 7600 cm2/Vs at 77 K is obtained at 1-X=0.25 and dB=1μm.