Shohei Nakahara

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Glass of generic composition SiO(2) . Al(2)O(3) . P(2)O(5) . CaO . CaF(2) will crystallise predominantly to apatite and mullite upon heat-treatment. Such ceramics are bioactive, osseoconductive, and have a high resistance to fracture. As a result, they are under investigation for use as biomedical device coatings, and in particular for orthopaedic implants.(More)
The origin of a marked difference in a dielectric constant, κ, observed between two types of strontium titanium oxide (STO) films sputter-deposited on platinum layers was investigated using a transmission electron microscopy method. The first type of STO films having a low κ value initially grew as an amorphous phase, followed by the formation of a randomly(More)
We propose a three-step model of electrochemical nanopore formation in n-InP in KOH that explains how crystallographically oriented etching can occur even though the rate-determining process (hole generation) occurs only at pore tips. The model shows that competition in kinetics between hole diffusion and electrochemical reaction determines the average(More)
The development of a cost-effective Si based platform on which III-V's can be grown is of great interest. This work investigates the morphology of gallium phosphide (GaP) films grown on {111} silicon (Si) substrates by means of liquid phase epitaxy in a tin (Sn) - based solvent bath. Two types of single-crystal {111} Si substrates were used; the first type(More)
A transmission electron microscope was used to characterize a powder form of hexagonally-ordered mesoporous silica material. The structural symmetry built into this amorphous material allowed one to obtain three characteristic images, i.e. a hexagonal honey-comb structure and wide/narrow parallel lines. These images were found to originate primarily from(More)
TEM analysis of mesoporous materials is generally undertaken to give qualitative results. Accurate quantitative analysis is demonstrated in this study. A systematic image analysis of a powder form of a hexagonal mesoporous material known as KIT-6 is conducted using a transmission electron microscope (TEM). Three types of image contrast typically appear in(More)
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