Yoko Kawamura

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Using ultraviolet-laser assisted local-electrode atom-probe ͑UV-LEAP͒ tomography, we obtain three-dimensional ͑3D͒ atom-by-atom images of isotopically modulated 28 Si and 30 Si ultrathin layers having thicknesses in the range of 5–30 nm. The 3D images display interfaces between the different monoisotopic layers with an interfacial width of ϳ1.7 nm, thus(More)
Polycarbonate is mainly a condensed polymer of bisphenol A and carbonyl chloride or diphenyl carbonate. Since it is transparent, has excellent heat resistance and impact resistance, and can be used for high-temperature uses and for microwave ovens, it is used in items such as children's tableware, tableware for meat services, coffee makers and food(More)
Small amounts of cyclic monomers and oligomers are present in polyamide (PA)-based kitchen utensils. In this study, we isolated eight PA-based cyclic monomers and oligomers from kitchen utensils made from PA6 (a polymer of ε-caprolactam) and PA66 (a polymer of 1,6-diaminohexane and adipic acid). Their structures were identified using high-resolution mass(More)
An analytical method for the identification and quantification of 10 different isocyanates and 11 different amines in polyurethane (PUR) foam and PUR-coated products was developed and optimized. Isocyanates were extracted and derivatized with di-n-butylamine, while amines were extracted with methanol. Quantification was subsequently performed by liquid(More)
Residual levels of 14 volatile substances, including 1,3-butadiene, acrylonitrile, benzene, ethylbenzene, and styrene, in 30 kitchen utensils made from acrylonitrile-butadiene-styrene resin (ABS) and acrylonitrile-styrene resin (AS) such as slicers, picks, cups, and lunch boxes in Japan were simultaneously determined using headspace gas chromatography/mass(More)