Nobuhiro Kikuchi

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Dot arrays with diameter ranging from 80 to 245 nm are made of Co 80 Pt 20 films with large perpendicular anisotropy. Magnetic properties are investigated by detecting the anomalous Hall effect. The all arrays show angular dependence of remanent coercivity similar to coherent rotation. The result shows that reversal process is independent of dot diameter.(More)
We present an observational and theoretical study of the spiral structure in galaxy NGC 1566. A digitized image of NGC 1566 in I-band, obtained with the Australian National University 30in telescope, was used for measurements of the radial dependence of amplitude variations in the spiral arms. The azimuthal variations of the surface brightness in the I-band(More)
SUMMARY We present a dual traveling-wave electrode InP-based Mach-Zehnder (MZ) modulator with an n-in waveguide structure. An electrical input/output interface placed on one side of the chip helps us to drive the modulator in a push-pull configuration. This configuration provides the modulator with great advantages such as reduced driving voltage amplitude,(More)
The switching fields and thermal stability of CoPt/Ru dot arrays with various dot thickness (5–20 nm) were experimentally investigated as a function of the dot diameter, , (130–300 nm). All dot arrays showed a single domain state, even after removal of an applied field equal to the remanence coercivity. The angular dependence of for the dot arrays indicated(More)
We have tested the applicability of the global modal approach in the density wave theory of spiral structure for a sample of six spiral galaxies: NGC 488, NGC 628, NGC 1566, NGC 2985, NGC 3938 and NGC 6503. The galaxies demonstrate a variety of spiral patterns from the regular open and tightly wound spiral patterns to a multi-armed spiral structure. Using(More)
We have tested the applicability of the global modal approach in the density wave theory of spiral structure for a sample of spiral galaxies with measured axisymmetric background properties. We report here the results of the simulations for four galaxies: NGC 488, NGC 628, NGC 1566, and NGC 3938. Using the observed radial distributions for the stellar(More)
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