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To develop the state‐of‐the‐art polymer membrane fuel cells. Both maximization of oxygen reduction reaction (ORR) activity on Pt cathode and minimization of Pt content in the cathode are required. For this challenge, the defect interface on oxide support was modified by proton beam irradiation method. Pt‐CeOx nanowire/C (Pt/C = 0.02) was fabricated using the proton beam irradiation method. Since the radical density generated by proton beam irradiation is two orders of magnitude greater than that of electron beam irradiation, the CeOx nanowire surface was fully converted to a thin layer of Pt‐O‐Ce bonds under proton beam irradiation. The ORR activity observed for fabricated sample with above active surface layer was higher than that of conventional Pt/C (Pt/C = 0.2) and comparable to that of Pt‐CeOx nanowire/C (Pt/C = 0.2) fabricated by conventional methods. From the combination of microanalysis characterization and surface atomistic simulation, we concluded that the Pt‐O‐Ce bond was formed on defect‐rich regions of the CeOx nanowire and this leads to a maximized ORR activity on the fabricated sample. Based on all experimental data, it is concluded that the surface modification of CeOx nanowire support using proton beam irradiation is useful for a lowering the Pt content of the cathode with high ORR activity. [ABSTRACT FROM AUTHOR]

Ion irradiation in liquid was performed using a tandem accelerator and beam injection with a glass capillary. Nanoparticles of transition metals (Ni, Cu, Ag, Pt, and Au) were grown in the solution by reduction of the metallic ions in a process induced by proton irradiation. We could deposit the particles directly on the substrate at the irradiated position. The size of the particles was controllable by continuing the irradiation. Bimetallic Pt–Cu particles could be formed at any elemental ratio. Incorporation of oxygen into the particles was suppressed by selecting a scavenger at an appropriate concentration. [ABSTRACT FROM AUTHOR]

Abstract: An ion irradiation system in liquid has been developed using a tapered glass capillary with a thin window at the tip. Irradiation at a solid–liquid interface is interesting because it can be applied to novel analysis, radiation testing, and surface modification processes. In this study, polyethylene and polytetrafluoroethylene were irradiated with H+ ions in an aqueous solution containing acrylic acid monomers. The irradiated surfaces which were originally hydrophobic became hydrophilic due to the surface layer formed by the acrylic acid polymer. [Copyright &y& Elsevier]

Fabrication of a microlens array film was explored by means of photoinduced reorientation of dye-doped polymerizable liquid crystals (LCs). LC monomer/photoinitiator mixtures doped with a small amount of an oligothiophene derivative were irradiated with a 488-nm beam from an Ar+ laser. Then the sample cell was periodically moved. After these two processes were repeated for a few tens times, remaining photoinitiators were quenched by irradiation with UV light. Observation of the cells with a polarizing optical microscope revealed that the molecular alignment of LCs induced by the Ar+ laser beam remained unchanged after the beam was turned off and a microlens array with a square-lattice type was obtained. This indicates that formation of the microlens and photopolymerization of the LC monomers are brought about simultaneously in a small area. The fabricated microlens has polarization selectivity that reflects molecular alignment. The focal length of the microlens arrays could be changed by controlling the irradiation intensity. Furthermore, a freestanding film with microlens arrays was obtained by peeling from the sample cell. [ABSTRACT FROM AUTHOR]

Abstract: A polytetrafluoroethylene (PTFE) surface is smooth and biologically inert, so that cells cannot attach to it. Ion beam irradiation of the PTFE surface forms micropores and a melted layer, and the surface is finally covered with a large number of small protrusions. Recently, we found that cells could adhere to this irradiated PTFE surface and spread over the surface. Because of their peculiar attachment behavior, these surfaces can be used as biological tools. However, the factors regulating cell adhesion are still unclear, although some new functional groups formed by irradiation seem to contribute to this adhesion. To control cell behavior on PTFE surfaces, we must determine the effects of the outermost irradiated surface on cell adhesion. In this study, we removed the thin melted surface layer by postirradiation annealing and investigated cell behavior on the surface. On the surface irradiated with 3×1016 ions/cm2, cells spread only on the remaining parts of the melted layer. From these results, it is clear that the melted layer had a capacity for cell attachment. When the surface covered with protrusions was irradiated with a fluence of 1×1017 ions/cm2, the distribution of cells changed after the annealing process from ‘sheet shaped’ into multicellular aggregates with diameters of around 50μm. These results indicate that we can control cell behavior on PTFE surfaces covered with protrusions using irradiation and subsequent annealing. Multicellular spheroids can be fabricated for tissue engineering using this surface. [Copyright &y& Elsevier]

Abstract: Silicone (polydimethylsiloxane) sheets and tubes for medical use were irradiated with inert gas ions using plasma-based ion implantation (PBII). The affinity of the surface with tissue examined by an animal test was improved by the irradiation at optimal conditions. The cell attachment percentage increased at an applied voltage of less than −7.5kV; however, it decreased at higher voltage. The specimens irradiated at higher voltages were more hydrophobic than unirradiated specimens. The surface became rough with increasing voltage and textures, and small domains appeared. This effect was caused by different etching speeds in the amorphous and crystalline areas. [Copyright &y& Elsevier]

Abstract: Application of nano and micro fabrication techniques in industry requires solution to some crucial problems. One of the significant problems is the sticking interface between mold surface and imprinted polymer. In this study, we report a solution to the sticking interface problem by modification of nano imprinting mold using fluorine ion implantation. After the fluorine implantation, anti sticking layer appeared on the nano imprinting mold surface. After the implantation, a mold made from glass like carbon was patterned by focused ion beam lithography. The pattern was made up of word “TIRI”. The line width was varied with 300nm, 500nm, and 1μm. The line depth was about 200∼300nm. The average depth of implanted fluorine was approximately 90nm. After imprinting, the resin was removed from the mold by mechanical lift-off process. Transferred pattern was observed and confirmed by a scanning electron microscope (SEM) and an atomic force microscope (AFM). The pattern transferred from mold to resin was found to be successful. [Copyright &y& Elsevier]

Neutron irradiation following thermal ageing experiments were performed using Fe-Cu, Fe-Cu-Ni, Fe-Cu-Ni-Mn, and Fe-Cu-Si alloys to investigate the effects of Ni, Mn, and Si on the formation of Cu-rich clusters and their chemical composition. Atom probe tomography showed that Ni and Mn increased the number density of Cu-rich clusters. This can be caused by that Ni and Mn reduce the formation energy of Cu nuclei, thus enhancing the Cu nucleation rate. Mn may also enhance the heterogeneous nucleation of Cu because of its strong interaction with self-interstitial atoms. In addition, Mn can accelerate solute diffusion during thermal ageing. A high Ni alloying content enhanced the Mn concentration in the clusters as well as the Ni concentration, which is believed to be caused by the thermodynamic relationship between Ni and Mn. In Fe-Cu-Si alloys, the Si concentration in the clusters was very low and was comparable to the Si alloying content. This indicates that Si atoms hardly cluster with Cu. [ABSTRACT FROM AUTHOR]