Showing papers by "Sophia University published in 2013"

A game theoretical analysis of port competition

Abstract: This paper examines the effect of inter-port competition between two ports by applying a game theoretical approach. We construct a non-cooperative game theoretic model where each port selects port charges strategically in the timing of port capacity investment. We derive the Nash equilibrium and obtain some propositions from the equilibrium. We then apply the propositions to the case of inter-port competition between the ports of Busan and Kobe.

Introduction to Nanoparticles

Abstract: Nanotechnology is the science that deals with matter at the scale of 1 billionth of a meter (i.e., 10 − 9 m = 1 nm), and is also the study of manipulating matter at the atomic and molecular scale. A nanoparticle is the most fundamental component in the fabrication of a nanostructure, and is far smaller than the world of everyday objects that are described by Newton ’ s laws of motion, but bigger than an atom or a simple molecule that are governed by quantum mechanics. The United States instituted the National Nanotechnology Initiative ( NNI ) back in 2000, which was soon followed (2001) by a plethora of projects in nanotechnology in nearly most of the U.S. Departments and Agencies [1] . About 20 Research Centers were subsequently funded by the Nationa1 Science Foundation ( NSF ), an agency responsible solely to the President of the United States and whose mandate is to fund the best of fundamental science and technology projects. NSF was the lead U.S. agency to carry forward the NNI. The word “nanotechnology” soon caught the attention of various media (TV networks, the internet, etc.) and the imagination and fascination of the community at large. In general, the size of a nanoparticle spans the range between 1 and 100 nm. Metallic nanoparticles have different physical and chemical properties from bulk metals (e.g., lower melting points, higher specifi c surface areas, specifi c optical properties, mechanical strengths, and specifi c magnetizations), properties that might prove attractive in various industrial applications. However, how a nanoparticle is viewed and is defi ned depends very much on the specifi c application. In this regard, Table 1.1 summarizes the defi nition of nanoparticles and nanomaterials by various organizations. Of particular importance, the optical property is one of the fundamental attractions and a characteristic of a nanoparticle. For example, a 20-nm gold nanoparticle has a characteristic wine red color. A silver nanoparticle is yellowish gray. Platinum and palladium nanoparticles are black. Not surprisingly, the optical characteristics of nanoparticles have been used from time immemorial in sculptures and 1

Monolithic Integration of InGaN-Based Nanocolumn Light-Emitting Diodes with Different Emission Colors

Abstract: We demonstrate the monolithic integration of green and orange InGaN-based nanocolumn light-emitting diodes (LEDs). Four nanocolumn LED crystals (LEDs 1 to 4), which consisted of regularly arranged InGaN-based nanocolumns in a triangular lattice of 400 nm lattice constant, were grown on the same GaN template on a (0001) sapphire substrate, with designed nanocolumn diameters D of 150, 190, 230, and 270 nm for LEDs 1–4, respectively. LEDs 1 to 3 operated under DC current injection at room temperature, emitting at 544, 583, and 597 nm, respectively. This experiment paves the way for the monolithic integration of three-primary-color nanocolumn LEDs.

Vortices and Other Topological Solitons in Dense Quark Matter

Abstract: In this review, we discuss various properties of topological solitons in dense QCD matter, with a particular emphasis on the CFL phase exhibiting superfluidity and superconductivity, and their phenomenological implications in terms of the effective field theories such as the Ginzburg-Landau theory, the chiral Lagrangian, or the Bogoliubov--de Gennes equation. The most fundamental topological excitations are non-Abelian vortices, which are 1/3 quantized superfluid vortices and color magnetic flux tubes. They are created at a phase transition or a rotation such compact stars. The intervortex-interaction is repulsive and consequently a vortex lattice is formed. Bosonic and fermionic zero-energy modes are trapped in the vortex core and propagate along it as gapless excitations. The former consists of translational zero modes (a Kelvin mode) with a quadratic dispersion and CP(2) Nambu-Goldstone gapless modes with a linear dispersion, while the latter is the triplet Majorana fermion zero modes. The low-energy effective theory of the bosonic zero modes is a non-relativistic free complex scalar field and a CP(2) model in 1+1 dimensions. The effects of strange quark mass, electromagnetic interactions and non-perturbative quantum corrections are taken into account. Colorful boojums at the CFL interface, quantum color magnetic monopole confined by vortices, which supports the notion of quark-hadron duality, and Yang-Mills instantons inside a vortex as lumps are discussed. The interactions between a vortex and quasi-particles such as phonons, gluons, mesons, and photons are studied. A vortex lattice is shown to behave as a cosmic polarizer. Non-Abelian vortices are shown to behave as a novel kind of non-Abelian anyons. For the chiral symmetry breaking, we discuss fractional and integer axial domain walls, Abelian and non-Abelian axial vortices, axial wall-vortex composites, and Skyrmions.

Disordered weak and strong topological insulators.

Abstract: A global phase diagram of disordered weak and strong topological insulators is established numerically. As expected, the location of the phase boundaries is renormalized by disorder, a feature recognized in the study of the so-called topological Anderson insulator. Here, we report unexpected quantization, i.e., robustness against disorder of the conductance peaks on these phase boundaries. Another highlight of the work is on the emergence of two subregions in the weak topological insulator phase under disorder. According to the size dependence of the conductance, the surface states are either robust or "defeated" in the two subregions. The nature of the two distinct types of behavior is further revealed by studying the Lyapunov exponents.

Control of microwave-generated hot spots. Part V. Mechanisms of hot-spot generation and aggregation of catalyst in a microwave-assisted reaction in toluene catalyzed by Pd-loaded AC particulates

Abstract: Hot spots are generated when carrying out the heterogeneous Suzuki–Miyaura cross coupling reaction for the synthesis of 4-methylbiphenyl in toluene solvent in the presence of Pd/AC catalyst (AC: activated carbon; see for example parts I–IV 1 ). Controlling these hot spots could render the microwave-assisted catalyzed reaction more effective. Accordingly, the present article examines the mechanism by which the hot spots are generated through particle aggregation observed by means of a high-speed camera; the influence of particle size was also examined. Moreover, the formation of hot spots within the spatial gap between two AC particles was simulated by an electromagnetic field analysis and subsequently evidenced experimentally. The heterogeneous Suzuki–Miyaura coupling reaction for the synthesis of 4-methylbiphenyl in toluene solvent in the presence of activated carbon (AC; no Pd) under microwave irradiation has been re-visited to ascertain what the effect of the reagents might be as to whether or not hot spots are formed. The presence of the reagents used in the synthesis of 4-methylbiphenyl did cause a firm connectivity between the activated carbon particles, which changed with the directions of the electric field and the magnetic field. The relationship between the generation of by-products and the formation of hot spots has also been considered in the synthesis of 4-methylbiphenyl in toluene solvent catalyzed by Pd/AC.

Critical exponent for the Anderson transition in the three dimensional orthogonal universality class

Abstract: We report a careful finite size scaling study of the metal insulator transition in Anderson's model of localisation. We focus on the estimation of the critical exponent $ u$ that describes the divergence of the localisation length. We verify the universality of this critical exponent for three different distributions of the random potential: box, normal and Cauchy. Our results for the critical exponent are consistent with the measured values obtained in experiments on the dynamical localisation transition in the quantum kicked rotor realised in a cold atomic gas.

Lattice QCD in Rotating Frames

Abstract: We formulate lattice QCD in rotating frames to study the physics of QCD matter under rotation. We construct the lattice QCD action with the rotational metric and apply it to the Monte Carlo simulation. As the first application, we calculate the angular momenta of gluons and quarks in the rotating QCD vacuum. This new framework is useful to analyze various rotation-related phenomena in QCD.

Full Duplex Media Access Control for Wireless Multi-Hop Networks

Abstract: Wireless full-duplexing enables a transmission and a reception on the same frequency channel at the same time, and has the potential to improve the end-to-end throughput of wireless multi-hop networks. In the present paper, we propose a media access control (MAC) protocol for wireless full- duplex and multi-hop networks called Relay Full- Duplex MAC (RFD-MAC). The RFD-MAC is an asynchronous full-duplex MAC protocol, which consists of a primary transmission and a secondary transmission. The RFD-MAC increases the full-duplex links by overhearing frames, which include 1-bit information concerning the existence of a successive frame, and selecting a secondary transmission node using the gathered information. The gathered information is also used to avoid a collision between the primary and secondary transmission. Simulation results reveal that the proposed RFD-MAC improves up to 68%, 49% and 56% of end-to-end throughput compared to CSMA/CA, FD-MAC and MFD-MAC, respectively.

Quark Cluster Model of Baryon-Baryon Interaction

Abstract: The quark cluster model of the baryon-baryon interaction is reviewed. The emphasis is on the foundation of the approach and the main features of the model. The origins of the short-range repulsion in the nuclear force and other baryonic interactions are discussed. The origin of the nuclear force is a central problem of nuclear physics. It has a long history since Yukawa 1) proposed the static one-pion exchange potential (OPEP) of the range of the pion Compton wave length. The discovery of the pion boosted both the experimental and theoretical investigation of the nuclear force. It was realized in the early stage that the short range part of the nuclear force requires further ingredients, including the two- and multi-pion exchange interactions. In order to study the shorter-range part, Taketani proposed to consider three regions of the nuclear force separately. 2) (I) The long-range part (R ≥ 2 fm) is described by OPEP. (II) The medium-range part (1 ≤ R ≤ 2 fm) is attributed to nonstatic part of the pion exchange, multipion exchanges and heavy meson exchanges. Finally, (III) the shortrange part (R ≤ 1 fm) is left for phenomenology as it is most “complicated”. The OPEP was firmly established since then and the region (II) was studied in various approaches that treat nonstatic contribution and heavy mesons. It is believed to give a strong attraction due mostly to exchange of two pions correlated in the S-wave, which is often represented by the exchange of a scalar sigma meson. It turned out that this strong attraction of the second region is crucial for the nuclear binding. The shortest range region (III) was found to have a strong repulsion as suggested from the medium-energy nucleon-nucleon ( NN ) scattering data. Thus the nuclear binding is on the balance between the attraction in the regions (I) and (II) and the repulsion in (III). Meanwhile, many phenomenological models have been constructed. Main source of information is the NN scattering observables as well as properties of the deuteron. The proposed models include the Hamada-Johnston potential, 3) the Reid soft core potential, 4) the Tamagaki potential, 5) all of which can explain the low energy observables fairly well. The real development in the study of region (II) was achieved in 1970’s resulting in two popular models of nuclear force, Bonn 6) and Paris 7) po

Influence of the image charge effect on excitonic energy structure in organic-inorganic multiple quantum well crystals

Abstract: We have experimentally compared the excitonic properties of hybrid multiple quantum wells, (C${}_{\text{6}}$H${}_{\text{5}}$-C${}_{\text{2}}$H${}_{\text{4}}$NH${}_{\text{3}}$)${}_{\text{2}}$PbBr${}_{\text{4}}$ and (C${}_{\text{4}}$H${}_{\text{9}}$NH${}_{\text{3}}$)${}_{\text{2}}$PbBr${}_{\text{4}}$, using photoluminescence, reflection, and photoluminescence excitation measurements. We focused on the contribution of the image charge effect (ICE) to the excitonic energy structure in these materials which have different dielectric constants of the barrier layers. We have found that the binding energies of the $2s$ and $3s$ excitons are considerably enhanced by ICE, while the contribution of ICE to the $1s$ excitons is smaller because of the small Bohr radius, which is comparable to the well width.

Quantum receivers with squeezing and photon-number-resolving detectors for M -ary coherent state discrimination

Abstract: We propose quantum receivers with optical squeezing and photon-number-resolving detectors (PNRDs) for the near-optimal discrimination of quaternary phase-shift-keyed coherent state signals. The basic scheme is similar to the previous proposals [e.g., Izumi et al., Phys. Rev. A 86, 042328 (2012)] in which displacement operations, on-off detectors, and electrical feedforward operations were used. Here we study two types of receivers, one of which installs optical squeezings and the other uses PNRDs instead of on-off detectors. We show that both receivers can attain lower error rates than that in the previous scheme. In particular, we show the PNRD-based receiver has a significant gain when the ratio between the mean photon number of the signal and the number of the feedforward steps is relatively high, in other words, when the probability of detecting two or more photons at each detector is not negligible. Moreover, we show that the PNRD-based receiver can suppress the errors due to dark counts, which the receiver with the on-off detector cannot do with a small number of feedforwards.

SO2 photoexcitation mechanism links mass-independent sulfur isotopic fractionation in cryospheric sulfate to climate impacting volcanism

Abstract: Natural climate variation, such as that caused by volcanoes, is the basis for identifying anthropogenic climate change. However, knowledge of the history of volcanic activity is inadequate, particularly concerning the explosivity of specific events. Some material is deposited in ice cores, but the concentration of glacial sulfate does not distinguish between tropospheric and stratospheric eruptions. Stable sulfur isotope abundances contain additional information, and recent studies show a correlation between volcanic plumes that reach the stratosphere and mass-independent anomalies in sulfur isotopes in glacial sulfate. We describe a mechanism, photoexcitation of SO2, that links the two, yielding a useful metric of the explosivity of historic volcanic events. A plume model of S(IV) to S(VI) conversion was constructed including photochemistry, entrainment of background air, and sulfate deposition. Isotopologue-specific photoexcitation rates were calculated based on the UV absorption cross-sections of 32SO2, 33SO2, 34SO2, and 36SO2 from 250 to 320 nm. The model shows that UV photoexcitation is enhanced with altitude, whereas mass-dependent oxidation, such as SO2 + OH, is suppressed by in situ plume chemistry, allowing the production and preservation of a mass-independent sulfur isotope anomaly in the sulfate product. The model accounts for the amplitude, phases, and time development of Δ33S/δ34S and Δ36S/Δ33S found in glacial samples. We are able to identify the process controlling mass-independent sulfur isotope anomalies in the modern atmosphere. This mechanism is the basis of identifying the magnitude of historic volcanic events.

Single-reference high-precision mass measurement with a multireflection time-of-flight mass spectrograph

Abstract: A multireflection time-of-flight mass spectrograph, competitive with Penning trap mass spectrometers, has been built at RIKEN. We have performed a first online mass measurement, using ${}^{8}$Li${}^{+}$ (${T}_{1/2}=838$ ms). A new analysis method has been realized, with which, using only ${}^{12}$C${}^{+}$ references, the mass excess of ${}^{8}$Li was accurately determined to be 20 947.6(15)(34) keV ($\ensuremath{\delta}m/m=6.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$). The speed, precision, and accuracy of this first online measurement exemplifies the potential for using this new type of mass spectrograph for precision measurements of short-lived nuclei.

Displaying Critical Thinking in EFL Academic Writing: A Discussion of Japanese to English Contrastive Rhetoric

Abstract: This article provides an examination of the literature on issues surrounding the problems Japanese university students face in learning critical argument in their English academic writing courses. Japanese students’ critical thinking skills are criticized as not fostered in their university education, perhaps due to Confucian education ideals, Japanese ‘reader-responsible’ rhetorical structures, or misinterpretations by Western instructors. The article is presented in four sections providing first, an examination of English L2 in the Japanese context, second, an analysis of Japanese to English contrastive rhetoric, and third, a discussion of the debate on Japanese university students’ critical thinking in EFL writing. The article finishes with several suggestions to provide ways of dealing with the key challenges and fostering more positive development of critical thinking in Japanese students’ EFL academic writing.

A hybrid microreactor/microwave high-pressure flow system of a novel concept design and its application to the synthesis of silver nanoparticles

Abstract: This article reports on a microreactor/microwave high-pressure flow hybrid apparatus of a novel concept design, which includes both the microreactor and a spiral reactor, and its efficient use in the synthesis of silver nanoparticles of relatively uniform sizes (4.3 ± 0.7 nm) under microwave irradiation. By contrast, under otherwise identical experimental conditions but with conventional heating, the nanoparticle size was non-uniform (8.3 ± 2.7 nm) and the spiral reactor walls were covered with a silver mirror deposit. Formation of the nanoparticles was monitored by UV–visible spectroscopy (plasmonic absorption band; LSPR), TEM and by small-angle X-ray scattering (SAXS). Both the spiral microreactor and the spiral quartz reactor of the hybrid system played an important role in the synthesis, with the microreactor providing the environment wherein mixing of the aqueous solution of [Ag(NH3)2]+ and the solution of glucose (the reducing agent) and poly(N-vinyl-2-pyrrolidone) (PVP; stabilizer/dispersing agent) occurred. The microwaves provided the thermal energy to effect a uniform growth of the silver nanoparticles at temperatures above 120 °C. Mixing the two solutions by conventional methods (no microreactor) failed to yield such nanoparticles even under microwave irradiation and no formation of a silver mirror occurred in the inner walls of the spiral reactor.

Control of microwave-generated hot spots. Part IV. Control of hot spots on a heterogeneous microwave-absorber catalyst surface by a hybrid internal/external heating method

Abstract: A problem with microwave-absorbing heterogeneous catalysts (MAHCs) in non-polar solvents is resolved with a novel approach that also uses an external heating bath in combination with microwave heating. In non-polar solvents, the microwave radiation dielectrically and selectively heats only the catalyst resulting in the frequent occurrence of hot spots under these conditions. However, such hot spots can be controlled through a combined (hybrid) internal/external heating methodology (MAHS). Moreover, high temperatures can be maintained with significant energy saving. The potential benefit of MAHS has been examined by carrying out the synthesis of 4-methylbiphenyl using the Suzuki–Miyaura coupling reaction in toluene solvent in the presence of palladium catalytic particles supported on activated carbon particulates (Pd/AC). The hybrid internal/external heating method saved 65% of microwave energy and increased the chemical yield of 4-methylbiphenyl nearly twofold in comparison with a conventional microwave heating method.

Investor response to a natural disaster: Evidence from Japan's 2011 earthquake

Abstract: Japan's most powerful known earthquake struck at 2:46 p.m. on Friday, March 11, 2011. We study the unusual trading behaviors of individual and foreign investors in Japan during the aftermath of this natural disaster. Individual investors typically show contrarian trading patterns, so the sharp downturn in the Nikkei should cause positive net purchases. Instead, purchases were significantly less than sales in the week after the earthquake. Foreign investors typically show positive feedback and momentum trading patterns. However, in the week after the earthquake, they seemed to have stabilized the Japanese stock markets by dramatically increasing their trading activity and net purchases.

Syntactic Computation in the Human Brain: The Degree of Merger as a Key Factor

Abstract: Our goal of this study is to characterize the functions of language areas in most precise terms. Previous neuroimaging studies have reported that more complex sentences elicit larger activations in the left inferior frontal gyrus (L. F3op/F3t), although the most critical factor still remains to be identified. We hypothesize that pseudowords with grammatical particles and morphosyntactic information alone impose a construction of syntactic structures, just like normal sentences, and that “the Degree of Merger” (DoM) in recursively merged sentences parametrically modulates neural activations. Using jabberwocky sentences with distinct constructions, we fitted various parametric models of syntactic, other linguistic, and nonlinguistic factors to activations measured with functional magnetic resonance imaging. We demonstrated that the models of DoM and “DoM+number of Search (searching syntactic features)” were the best to explain activations in the L. F3op/F3t and supramarginal gyrus (L. SMG), respectively. We further introduced letter strings, which had neither lexical associations nor grammatical particles, but retained both matching orders and symbol orders of sentences. By directly contrasting jabberwocky sentences with letter strings, localized activations in L. F3op/F3t and L. SMG were indeed independent of matching orders and symbol orders. Moreover, by using dynamic causal modeling, we found that the model with a inhibitory modulatory effect for the bottom-up connectivity from L. SMG to L. F3op/F3t was the best one. For this best model, the top-down connection from L. F3op/F3t to L. SMG was significantly positive. By using diffusion-tensor imaging, we confirmed that the left dorsal pathway of the superior longitudinal and arcuate fasciculi consistently connected these regions. Lastly, we established that nonlinguistic order-related and error-related factors significantly activated the right (R.) lateral premotor cortex and R. F3op/F3t, respectively. These results indicate that the identified network of L. F3op/F3t and L. SMG subserves the calculation of DoM in recursively merged sentences.