Enhanced oxygen reduction reaction performances were achieved on size-controlled Pt nanoparticle catalysts prepared by the copolymerization of a Pt4-pyrrole complex and pyrrole monomer in the presence of multi-wall carbon nanotubes.

A novel multiwall carbon nanotube (MWCNT) and polypyrrole (PPy) composite was found to be useful for preparing durable Pt nanoparticle catalysts of highly regulated sizes. A new pyrene-functionalized Pt complex was attached to the MWCNT surface which was functionalized with PPy matrix to yield Pt complex/PPy/MWCNT composites without decomposition of the Pt complex units. The attached Pt complexes in the composite were transformed into Pt nanoparticles with sizes of 1.0-1.3 nm at a Pt loading range of 2 to 4 wt %. The Pt nanoparticles in the composites were found to be active and durable catalysts for the N-alkylation of aniline with benzyl alcohol. In particular, the Pt nanoparticles with PPy matrix exhibited high catalyst durability in up to four repetitions of the catalyst recycling experiment compared with nonsize-regulated Pt nanoparticles prepared without PPy matrix. These results demonstrate that the PPy matrix act to regulate the size of Pt nanoparticles, and the PPy matrix also offers stability for repeated usage for Pt nanoparticle catalysis.

A flexible string is used at various places. Typical examples are a cable for power transmission and communication and a wire for cranes and elevators. In addition, there are the uses such as a fly-fishing line, climbing rope and a mowing machine to cut turf by turning a nylon string. In the past study, a string pendulum was paid attention as the basic motion of the string. An analysis model of the string pendulum was made and appropriateness of the modeling and the behavior of the string pendulum were clarified. However, axial elongation is not considered. In fact, the string extends in the axial direction by the mass of itself and the external force, and it is expected that the behavior of the string is affected by the axial elongation. Therefore, it is thought that it is necessary to carry out numerical simulation in consideration of the axial elongation in order to grasp the behavior of the string more exactly. In addition, it is indispensable to take elongation into account when we analyze the behavior of a string-formed structure producing the great amount of elongation such as the rubber string. In this study, an analysis model considering axial elongation is made. The behavior of the string pendulum and the behavior when the string is given initial elongation and is released are paid attention and appropriateness of the modeling is verified by comparing experiment results and analysis results.