Roy Katayama

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DISCLAIMER: Policy Research Notes represent the views of the authors and do not necessarily represent WBG views or policy. The views expressed herein should be attributed to the authors and not to the WBG, its Board of Executive Directors, or its management. This note reflects data available as of mid-September 2015. Policy Research Notes (PRNs) are(More)
We study hadron properties near the deconfining transition in the quenched lattice QCD simulation. This paper focuses on the heavy quarkonium states, such as J/ψ meson. In order to treat heavy quarks at T > 0, we adopt the O(a) improved Wilson action on anisotropic lattice. We discuss cc̄ bound state observing the wave function and compare the meson(More)
The GaAsN alloy has attracted much attention due to the scientific interest for the huge bandgap bowing as well as the technological importance for optoelectronic devices. The study of the bandgap energy for the higher N contents, however, is scarcely reported because of the extreme immiscibility. In this work, the bandgap energy and its temperature(More)
GaAs<sub>0.949</sub>N<sub>0.051</sub>/GaAs multiple quantum wells (MQWs) were grown on GaAs (001) substrates by metalorganic vapor phase epitaxy (MOVPE). Strong photoluminescence (PL) emission around the 1.3-&#x003BC;m-wavelength region was observed without post-growth thermal annealing, which suggests an efficient electron confinement in the(More)
Optical properties of In<sub>x</sub>Ga<sub>1-x</sub>P<sub>1-y</sub>N<sub>y</sub>/GaP lattice-matched single quantum wells (SQWs) with different well widths (L<sub>z</sub> = 1.6 - 6.4 nm) at different In (x = 0.050 - 0.135) and N (y = 0.025 - 0.071) concentrations have been investigated by low-temperature photoluminescence (PL) and PL-excitation (PLE). The(More)
InAs<sub>l-x</sub>N<sub>x</sub> epilayers even with x=0.0353 were successhlly grown on GaAs (001) substrates by using the ~0.8&#x003BC;m thick InAs buffer layer. The N concentration was well controlled by altering T<sub>g</sub> between 420&#x000B0;C and 510&#x000B0;C. With decreasing T<sub>g</sub> the N concentration of the InAsN layer increased. The(More)
Brazil’s inequalities in welfare and poverty between and within regions can be accounted by differences in household attributes and returns to those attributes. Using Blinder-Oaxaca decompositions at the mean as well as at different quantiles of welfare distributions on regionally representative household survey data (2002-03 POF), this paper finds that(More)
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