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Search Results: 1 - 10 of 565 matches for " Toshiaki Nagshima "
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Color Barrier Free Displays in Disaster Situations  [PDF]
Kensei Tsuchida, Chieko Kato, Toshiaki Nagshima
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.42005
Abstract:

Concerning color barrier free, there have been many research studies and an increasing interest in it. For example, to expand activities for the promotion of colorblind-friendly designs not only among scientists but also among industrial products and public facilities, the non-profit organization CUDO (Color Universal Design Organization) was established in 2004. However, there has been very little research of this type focusing on disaster situations. From their experiences volunteering in reconstruction support for victims of the 2011 tsunami, the authors came to recognize the importance for both non-colorblind and colorblind people to notice and distinguish emergency escape notifications, cautions and passage maps quickly and accurately. Therefore this research is aimed at the realization of color barrier free displays in disaster situations. Initially, requirements for color barrier free displays in disaster situations were analyzed. Four desirable criteria were derived as a result: “eye-catching”, “instantly-readable”, “unmistakable” and “stable”. In order to evaluate given signs from the viewpoint of the above criteria, evaluation experiment systems for displays in disaster situations were developed. With the evaluation experiment systems it would be possible to design effective signs and maps as color barrier free displays in disaster situations.

The Applicability of Gd-DTPA Magnetic Resonance Imaging Contrast Agent for the Evaluation of Blood Compartment Flow Distribution in Hollow Fiber Hemodialyzers  [PDF]
Bimali Sanjeevani Weerakoon, Toshiaki Osuga
Journal of Biomedical Science and Engineering (JBiSE) , 2015, DOI: 10.4236/jbise.2015.811075
Abstract: Observation of flow distribution pattern in the hemodialyzers is significant as it is a valuable in-dication of the performance of these modules. Therefore, in this study, a feasible non-destructive Magnetic Resonance Imaging (MRI) technique is proposed to characterize the flow distribution in the blood compartment of hemodialyzers using Gd-DTPA MRI contrast agent. The distribution of flow is qualitatively observed in two commercial clinical dialyzers through an in-vitro experiment. The contrast enhanced T1 weighted images are acquired along the dialyzer length using Spin Echo (SE) pulse sequence after an injection of 0.5 mmol/L Gd-DTPA solution into the blood compartment. Although relatively uniform flow distribution pattern over the spatial volume of transverse images, close the dialyzer inlet is observed, the heterogeneity of flow distribution can be identified towards the blood outlet port. Furthermore, the signal intensity profiles formed by the injected Gd-DTPA are gradually decreased towards the outlet port. These results of the study suggest that although no advanced techniques and protocols available, MRI and Gd-DTPA contrast agent can be utilized to characterize the flow distribution within a dialyzer qualitatively.
Comb-Line Filter with Coupling Capacitor in Ground Plane
Toshiaki Kitamura
Active and Passive Electronic Components , 2011, DOI: 10.1155/2011/919240
Abstract: A comb-line filter with a coupling capacitor in the ground plane is proposed. The filter consists of two quarter-wavelength microstrip resonators. A coupling capacitor is inserted into the ground plane in order to build strong coupling locally along the resonators. The filtering characteristics are investigated through numerical simulations as well as experiments. Filtering characteristics that have attenuation poles at both sides of the passband are obtained. The input susceptances of even and odd modes and coupling coefficients are discussed. The filters using stepped impedance resonators (SIRs) are also discussed, and the effects of the coupling capacitor for an SIR structure are shown. 1. Introduction Miniaturization of microwave filters is highly demanded. For mobile telephones especially, ceramic laminated filters [1–4] have been widely used, and in particular, comb-line filters have extensively made practical use. In this study, comb-line filters in which both sides of the substrate are utilized are considered. Comb-line filters consist of two quarter-wavelength resonators, and attenuation poles can be created in the frequency characteristics of the transmission parameter by changing the coupling locally along the resonators [5]. The stopband characteristics can be improved by arranging the attenuation poles around the passband. In [1, 2], strong coupling between two resonators is obtained by installing a patch conductor on the dielectric substrate above the resonators. The patch conductor is referred to as a coupling capacitor ( ). The method of installing a coupling capacitor by inserting slots into the ground plane is discussed. By this method, a coupling capacitor can be achieved without using a multilayered structure. As a method of inserting slots into a ground plane, a defected ground structure (DGS) has been attracting much attention [6–8]. In a broad sense, the proposed structure is a kind of DGS. The filtering characteristics are investigated through numerical simulations as well as experiments. The filters using stepped impedance resonators (SIRs) are also discussed, and the effects of the coupling capacitor for an SIR structure are shown. 2. Filter Structure Figure 1 shows an overview of the proposed comb-line filter. Two microstrip resonators are arranged on the substrate, and each resonator is terminated through the ground plane at one end using a through hole. As an I/O port, a microstrip line with a characteristic impedance of 50?ohm is directly connected to each resonator. A square-shaped coupling capacitor is fabricated by
Corrosion Protection of Steels by Conducting Polymer Coating
Toshiaki Ohtsuka
International Journal of Corrosion , 2012, DOI: 10.1155/2012/915090
Abstract: The corrosion protection of steels by conducting polymer coating is reviewed. The conducting polymer such as polyaniline, polypyrrole, and polythiophen works as a strong oxidant to the steel, inducing the potential shift to the noble direction. The strongly oxidative conducting polymer facilitates the steel to be passivated. A bilayered PPy film was designed for the effective corrosion protection. It consisted of the inner layer in which phosphomolybdate ion, (PMo), was doped and the outer layer in which dodecylsulfate ion (DoS) was doped. The inner layer stabilized the passive oxide and the outer possessed anionic perm-selectivity to inhibit the aggressive anions such as chloride from penetrating through the PPy film to the substrate steel. By the bilayered PPy film, the steel was kept passive for about 200?h in 3.5% sodium chloride solution without formation of corrosion products. 1. Introduction Since the investigation of Shirakawa et al. on conducting polyacetylene, various applications of conducting polymer have been reported [1]. Utilization of the conducting polymer for corrosion protection coating is one of these applications, and many papers have been presented in the last decade. Preparation of polyacetylen was made by oxidation in gaseous phase; however, at present, the conducting polymers such as polyaniline (PAni), polypyrrole (PPy), and polythiophen (Pthio) in Figure 1 for the corrosion protection have been prepared by electrochemical oxidation in liquid phase. Figure 1: Typical conducting polymers: (a) polypyrrole (PPy), (b) polythiophen (PThio), and (c) polyaniline (PAni). For application of the conducting polymer to corrosion protection, DeBerry was firstly reported in 1985, who presented that the stainless steel covered by PAni was kept in the passive state for relatively long period in sulfuric acid solution [2]. Wessling then pointed out that the conducting polymer coating of polyaniline and polypyrrole possibly possessed self-healing properties, in which the passive oxide between the substrate metal and the conducting polymer could be spontaneously reformed at a flawed site by oxidative capability of the conducting polymer [3]. When anodic potentials are applied to electrodes covered by the conducting polymers shown in Figure 1 after the polymerization, the oxidative property is provided in addition to the conductivity. The ability of the conducting polymer to oxidize the substrate steels allows potential of steels to be shifted to the passive state, in which the steels are protected by the passive oxide formed beneath the
Nitrosyltris(pyridine-2-thiolato-κ2N,S)molybdenum(II) dihydrate
Toshiaki Yonemura
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809043712
Abstract: In the title compound, [Mo(C5H4NS)3(NO)]·2H2O, the Mo atom is coordinated by a nitrosyl ligand and three monoanionic N,S-bidentate ligands in a distorted MoN4S3 pentagonal-bipyramidal molecular geometry. The pyridine N atom of one pyridine-2-thiolate (pyt) ligand is coordinated to the Mo atom in the trans position relative to the NO ligand [N(pyt)—Mo—N(NO) = 170.62 (19)°]. The compound has Cs symmetry, with a mirror plane that includes one pyt ring and the NO group. The S—Mo—N(NO) and N(pyt)—Mo—N(NO) angles [97.24 (12) and 91.87 (8)°, respectively] are large relative to the ideal angles of 90°. In the crystal, the molecules pack in a zigzag arrangement. The cavities between the molecules are occupied by disordered water molecules of crystallization.
Graphene edges; localized edge state and electron wave interference
Enoki Toshiaki
EPJ Web of Conferences , 2012, DOI: 10.1051/epjconf/20122300017
Abstract: The electronic structure of massless Dirac fermion in the graphene hexagonal bipartite is seriously modified by the presence of edges depending on the edge chirality. In the zigzag edge, strongly spin polarized nonbonding edge state is created as a consequence of broken symmetry of pseudo-spin. In the scattering at armchair edges, the K-K’ intervalley transition gives rise to electron wave interference. The presence of edge state in zigzag edges is observed in ultra-high vacuum STM/STS observations. The electron wave interference phenomenon in the armchair edge is observed in the Raman G-band and the honeycomb superlattice pattern with its fine structure in STM images.
Numerical Analysis of Ridged-Circular Nanoaperture for Near-Field Optical Disk
Toshiaki Kitamura
ISRN Optics , 2013, DOI: 10.1155/2013/543960
Abstract: A ridged-circular nanoaperture is investigated through three-dimensional (finite-difference time-domain) FDTD method. The motion equations of free electrons are inserted to analyze a metallic material. The electromagnetic field distributions of optical near-field around the aperture are investigated. The phase change disk illuminated by a near-field optical light through a ridged-circular nanoaperture is also analyzed. The far-field scattering patterns from the phase change disk and the crosstalk characteristics between plural marks are studied. 1. Introduction The recording density of conventional optical recording systems has an optical diffraction limit. Recently, there has been a lot of interest in the field of optical storage technologies for the recording methods that are based on near-field optical principles. This is because they have the potential to overcome the limitation by using the localized optical near-field for writing and reading recorded marks. Many types of nanoapertures and nanoantennas have been proposed to achieve the high throughput of the optical near-field [1–4]. This study focuses on a ridged-circular nanoaperture for a near-field optical disk. The analysis is accomplished by the FDTD method into which the motion equations of free electrons are inserted [5–7]. This method can easily deal with Drude dispersion and it can be applied to the analysis of various plasmonic devices. First, the electromagnetic field distributions of optical near-field around the ridged-circular nano-aperture are analyzed. Next, the scattering characteristics from a phase change disk with the aperture are studied. Finally, the crosstalk characteristics between plural marks are discussed. 2. FDTD Formulation In the FDTD method, special handling of the metallic material is required because the permittivity is dispersive and has a negative value in the optical frequency. In this study, the following motion equation is introduced into the FDTD method to evaluate the conducting current: where is the electron velocity, is the electric field, is the elementary electric charge, is the electron mass, and is the collision frequency. The collision frequency is expressed as follows: where is the angular frequency of a light wave and and are the real and imaginary parts, respectively, of the complex refractive index of a metallic material ( ). Maxwell’s equations are expressed as follows by representing the current density using the electron velocity and the electron density : where is the magnetic field and and are the electric permittivity and magnetic
Peripheral B Cells as Reservoirs for Persistent HCV Infection
Toshiaki Mizuochi
Frontiers in Microbiology , 2011, DOI: 10.3389/fmicb.2011.00177
Abstract:
Pressure-induced isostructural phase transition of metal-doped silicon clathrates
Toshiaki Iitaka
Physics , 2006, DOI: 10.1103/PhysRevB.75.012106
Abstract: We propose an atomistic model for the pressure-induced isostructural phase transition of metal-doped silicon clathrates, Ba8Si46 and K8Si46, that has been observed at 14 GPa and 23 GPa, respectively. The model explains successfully the equation of state, transition pressure, change of Raman spectra and dependence on the doped cations as well as the effects of substituting Si(6c) atoms with noble metals.
N-fold Parasupersymmetry
Toshiaki Tanaka
Physics , 2006, DOI: 10.1142/S0217732307024176
Abstract: We find a new type of non-linear supersymmetries, called N-fold parasupersymmetry, which is a generalization of both N-fold supersymmetry and parasupersymmetry. We provide a general formulation of this new symmetry and then construct a second-order N-fold parasupersymmetric quantum system where all the components of N-fold parasupercharges are given by type A N-fold supercharges. We show that this system exactly reduces to the Rubakov-Spiridonov model when N=1 and admits a generalized type C 2N-fold superalgebra. We conjecture the existence of other `N-fold generalizations' such as N-fold fractional supersymmetry, N-fold orthosupersymmetry, and so on.
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