Ikuya Kinefuchi

Thermal decomposition of ultrathin oxide layers on silicon surface was investigated with temperature programed desorption. Oxide layers were formed on Si(100) at 400 degrees C by exposure to O(2) molecular beam. Desorption spectrum for oxygen coverages between 1.7 and 2.6 ML exhibits a single dominant peak with an additional broad peak at lower temperatures. The former peak corresponds to stable binding states of O atoms at dimer bridge sites and dimer backbond sites. The high peak intensity ind

In polymer electrolyte membrane fuel cells, carbon-supported platinum (Pt/C) catalyst particles require sufficient water condensation within the nanoscale pores to effectively utilize the interior Pt catalysts. Since experimental visualizations with nanoscale precision of this phenomenon are not yet possible, we utilized a Pt/C catalyst particle reconstructed from segmented nanoimaging of a catalyst powder, which served as the computational domain for lattice density functional theory (LDFT) sim

The interaction of N2 molecules with a graphite (0001) surface was investigated employing the molecular beam experiment. The experimental setup involving a quadrupole mass spectrometer fixed on a rotary platform and a three‐axis substrate manipulator enabled us to measure the out‐of‐plane scattering as well as the in‐plane one. We examined a dependence of the scattering distribution on the translational energy of the incident beam. The obtained scattering distribution showed the lobular pattern

We present the analysis of gas transport in micro porous layers of polymer electrolyte fuel cells based on the three-dimensional structure data obtained from X-ray nano computed tomography (CT). The characteristic pore size is comparable to the mean free path of gas molecules. The polygonal surface representation of the porous structure is constructed from the volumetric CT image using the marching tetrahedrons algorithm. The diffusion fluxes of gas molecules through the porous layer are evaluat

Since gas flows in micro/nano devices are dominated by the interaction of gas molecules and solid surfaces, surface modification technique is one of the critical issues for optimizing the thermal performance of these devices. In this paper, we demonstrate the successful application of vertically aligned single-walled carbon nanotubes (VA-SWNTs) as surface modification material to enhance the energy accommodation of gas molecules on surfaces. The scattering of gas molecules on quartz surfaces cov

The microstructure of the polymer electrolyte membrane fuel cell (PEMFC) cathode catalyst layer (CCL) critically influences key transport phenomena, directly impacting fuel cell performance. Accurate three-dimensional (3D) reconstruction of the CCL is essential for understanding structure-property relationships and optimizing material design. This study presents a machine learning-driven framework for 3D reconstruction of PEMFC catalyst layers from focused ion beam-scanning electron microscopy (

Thermal decomposition of ultrathin oxide layers on Si(100) surface was investigated with temperature programmed desorption. The SiO desorption spectra for the initial coverages between 1.7 and 2.6 ML exhibit a dominant peak with a subpeak at lower temperature. The desorption rate corresponding to the dominant peak follows Avrami kinetics, suggesting that the decomposition process is spatially inhomogeneous with void formation and growth and is rate-limited by the desorption of SiO molecules at t

Abstract not Available.