Tokushima, Japan

Anan College of Technology
Tokushima, Japan

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Okamoto H.,Anan College of Technology | Yamaguchi K.,Kagawa University | Haraguchi M.,Tokushima University | Okamoto T.,Tokushima University
Applied Physics B: Lasers and Optics | Year: 2012

We fabricated and investigated a plasmonic racetrack resonator with a trench structure. Trench channel plasmon polaritons excited by end-fire coupling at a wavelength of 633 nm are observed in the fabricated racetrack resonator. The racetrack resonator also worked as a plasmonic racetrack resonator. The experimental and simulation results of the electric field distributions are in good agreement. © 2012 Springer-Verlag.

Ichinose G.,Anan College of Technology | Tenguishi Y.,Anan College of Technology
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

In this paper, we numerically investigate the robustness of cooperation clusters in prisoner's dilemma played on scale-free networks, where the network topologies change by continuous removal and addition of nodes. Each removal and addition can be either random or intentional. We therefore have four different strategies in changing network topology: random removal and random addition (RR), random removal and preferential addition (RP), targeted removal and random addition (TR), and targeted removal and preferential addition (TP). We find that cooperation clusters are most fragile against TR, while they are most robust against RP, even for large values of the temptation coefficient for defection. The effect of the degree mixing pattern of the network is not the primary factor for the robustness of cooperation under continuous change in network topology, which is quite different from the cases observed in static networks. Cooperation clusters become more robust as the number of links of hubs occupied by cooperators increase. Our results might infer the fact that a huge variety of individuals is needed for maintaining global cooperation in social networks in the real world where each node representing an individual is constantly removed and added. © 2013 American Physical Society.

Kawamoto S.,Tunghai University | Matsuo T.,Anan College of Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We calculate emission rates of various bosonic/fermionic soft massless states of an open/closed superstring from an ensemble of a highly excited open/closed superstring in the flat background. The resulting spectrum shows thermal distributions at the Hagedorn temperature. We find greybody factors for each process and observe their relation to the ones from black holes. © 2013 American Physical Society.

Sugiyama Y.-K.,Anan College of Technology | Okamoto S.,Kanagawa University
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2016

Cobalt-catalyzed [2 + 2 + 2] cocycloaddition reaction of 1,6-diynes and nitriles to generate substituted pyridines has been applied to the polymerization of diyne-nitrile monomers, the reaction of which proceeded smoothly in a step-growth fashion to provide linear polymers comprising pyridine structures in the main chain. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 345-351.

Toujyou T.,Anan College of Technology | Tsukamoto S.,Anan College of Technology
Nanoscale Research Letters | Year: 2010

Site-controlled InAs nano dots were successfully fabricated by a STMBE system (in situ scanning tunneling microscopy during molecular beam epitaxy growth) at substrate temperatures from 50 to 430°C. After 1.5 ML of the InAs wetting layer (WL) growth by ordinal Stranski-Krastanov dot fabrication procedures, we applied voltage at particular sites on the InAs WL, creating the site where In atoms, which were migrating on the WL, favored to congregate. At 240°C, InAs nano dots (width: 20-40 nm, height: 1.5-2.0 nm) were fabricated. At 430°C, InAs nano dots (width: 16-20 nm, height: 0.75-1.5 nm) were also fabricated. However, these dots were remained at least 40 s and collapsed less than 1000 s. Then, we fabricated InAs nano dots (width: 24-150 nm, height: 2.8-28 nm) at 300°C under In and As 4 irradiations. These were not collapsed and considered to high crystalline dots. © 2010 The Author(s).

Konishi T.,Anan College of Technology | Tsukamoto S.,Anan College of Technology
Nanoscale Research Letters | Year: 2010

Surface of an InAs wetting layer on GaAs(001) preceding InAs quantum dot (QD) formation was observed at 300°C with in situ scanning tunneling microscopy (STM). Domains of (1 × 3)/(2 × 3) and (2 × 4) surface reconstructions were located in the STM image. The density of each surface reconstruction domain was comparable to that of subsequently nucleated QD precursors. The distribution of the domains was statistically investigated in terms of spatial point patterns. It was found that the domains were distributed in an ordered pattern rather than a random pattern. It implied the possibility that QD nucleation sites are related to the surface reconstruction domains. © 2010 The Author(s).

Kobayashi M.,Anan College of Technology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

This paper proposes a new isotropic cellular automaton (CA) model for reproducing the Belousov–Zhabotinsky reaction observed in excitable media. Although several CA models have been proposed that exhibit isotropic patterns of the reaction, most of them need complicated rules, a large number of neighboring cells, and multiple thresholds to decide the excitation condition of cells. The proposed model uses only one threshold and simple time-evolution rules on the basis of states of selected neighboring cells; the selected cells are randomly chosen from eight neighboring cells. It is this randomness in selecting neighboring cells that causes the model to generate isotropic patterns. This study shows that patterns generated by the proposed model are highly isotropic. Furthermore, we use simulation results to elucidate how generated patterns are related to the initial states assigned to central cells. © Springer International Publishing Switzerland 2014.

Okamoto H.,Anan College of Technology | Kusaka K.,Anan College of Technology
Plasmonics | Year: 2014

We have presented a strain-sensing device in microscale by using surface plasmon polaritons and multimode interference effects. The device is numerically investigated by the finite-difference time-domain method. Optimum depths and length of the structure are designed for sensing a strain. The size of the designed structure is several micrometers and is about a thousandth compared with a fiber Bragg grating strain sensor. The sensitivity of the designed structure is 11.34 pm/μ𝜖 that is about ten times larger than that of a fiber Bragg grating strain sensor. The temperature sensitivity of the designed structure is 34.43 pm/ ∘C. This temperature sensitivity is three times larger than that of a fiber Bragg grating strain sensor. Therefore, temperature compensation techniques are needed for the structure. The presented structure has a simple design such as a plasmonic waveguide with a trench structure. The simple structural design device has a capability of being used in micro- and nano-electromechanical systems. © 2014, Springer Science+Business Media New York.

Ichinose G.,Anan College of Technology | Saito M.,Anan College of Technology | Sayama H.,Binghamton University State University of New York | Wilson D.S.,Binghamton University State University of New York
Scientific Reports | Year: 2013

Migration is a fundamental trait in humans and animals. Recent studies investigated the effect of migration on the evolution of cooperation, showing that contingent migration favors cooperation in spatial structures. In those studies, only local migration to immediate neighbors was considered, while long-range migration has not been considered yet, partly because the long-range migration has been generally regarded as harmful for cooperation as it would bring the population to a well-mixed state that favors defection. Here, we studied the effects of adaptive long-range migration on the evolution of cooperation through agent-based simulations of a spatial Prisoner's Dilemma game where individuals can jump to a farther site if they are surrounded by more defectors. Our results show that adaptive long-range migration strongly promotes cooperation, especially under conditions where the temptation to defect is considerably high. These findings demonstrate the significance of adaptive long-range migration for the evolution of cooperation.

Konishi T.,Anan College of Technology | Tsukamoto S.,Anan College of Technology
Surface Science | Year: 2011

We perform spatial point analysis of InAs quantum dot (QD) nucleation sites and surface reconstruction domain patterns on an InAs wetting layer to investigate QD nucleation mechanisms in Stranski-Krastanow growth mode. An InAs wetting layer on a GaAs(001) substrate has been observed at 300 °C by using in situ scanning tunneling microscopy (STM) preceding QD formation. A nearest-neighbor analysis of the STM images finds that the point pattern of QD precursors is similar to that of (1 × 3)/(2 × 3) surface reconstruction domains which are specific to Ga-rich fluctuation. This provides the evidence that InAs QD nucleation is induced by Ga-rich fluctuation within an InAs wetting layer, as a technical implication for site-controlled QD growth for various QD devices. © 2011 Elsevier B.V. All rights reserved.

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