Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2020 ( 98 )

2019 ( 464 )

2018 ( 521 )

2017 ( 543 )

Custom range...

Search Results: 1 - 10 of 326283 matches for " S. Takeuchi "
All listed articles are free for downloading (OA Articles)
Page 1 /326283
Display every page Item
Tameshi-Giri (and Suemono-Giri) As a Sub-Cultural Custom and Social Structure in Feudal Era Japan: A Socio-Cultural Analysis of Transformation of Its Symbolic Meanings and Functions.
Alexander S Takeuchi
Asian Social Science , 2009, DOI: 10.5539/ass.v5n11p3
Abstract: “Tameshi-giri” (or “suemono-giri”), in which corpses were used as mediums to test the quality of swords or the skill of swordsmen, was an unusual cultural practice of the samurai (i.e., warrior) class in feudal era Japan. Although tameshi-giri as a modern martial art jargon referring to “a method of training in the use of a sword by cutting conventional mediums” has already been imported to the Western world, the original socio-cultural meanings it symbolized as a sub-cultural custom and its societal functions as a social structure of pre-modern Japan are rarely discussed in the context of social science. Given this, the purpose of this paper is to offer a social-historical analysis of the old tameshi-giri custom as a social structure by focusing on the transformation of its manifest and latent functions. In doing so, it also aims to clarify some of the misconceptions and confusions associated with it.
Structure of the X(3872) and its Isospin Symmetry Breaking
Takizawa M.,Takeuchi S.
EPJ Web of Conferences , 2010, DOI: 10.1051/epjconf/20100303026
Abstract: In order to understand the structure of the X(3872), we have studied the e ects of the ${c}ar{c}$ charmonium core state coupling to the D0 $ar{D^{0}*}$ and D+ D * molecule states. We determine the coupling strength so as to reproduce the observed mass of the the X(3872). The isospin symmetry breaking is introduced by the mass di erences of the neutral and charged $ar{D*}}$ mesons. The obtained structure of the X(3872) is about 15% of ${c}ar{c}$ charmoniumu, 72% of the isoscalar D$ar{D*}}$ molecule and 13% of the isovector D$ar{D*}}$ molecule which explains observed properties of the X(3872) well.
Baryon resonances in the baryon meson scattering coupled to the q3-state
Takeuchi S.,Shimizu K.
EPJ Web of Conferences , 2010, DOI: 10.1051/epjconf/20100307017
Abstract: We investigate Λ(1405), (1232), and N* (1440) as resonances in the baryon-meson scattering with bound states embedded in the continuum (BSEC). This BSEC is introduced by hand, as a state not originated from a simple baryon-meson system. We assume it comes from the three-quark state. The resonances are successfully reproduced by this scheme. As for the Λ(1405) resonance, it is found that our calculation can give an appropriate energy and width for the peak and reproduces the ${m N}ar{K}$ scattering length when the BSEC contribution to the resonance is roughly half of that of the ${m N}ar{K}$ channel. The energy of the three-quark pole for (1232) is taken to be 1327 MeV, which comes down to 1232 MeV after the mixing to the Nπ and π scattering states is included. The nucleon also gets the self energy of about 130 MeV, so the N mass di erence, which is one of the key values in the quark model, does not change much. It also found that the positive parity excited nucleon mass can be reduced by more than 400 MeV and become around 1440 MeV after the mixing to the continuum is taken into account.
Direct CP, T and/or CPT violations in the K^0-\bar{K^0} system - Implications of the recent KTeV results on $2π$ decays -
Y. Takeuchi,S. Y. Tsai
Physics , 1999, DOI: 10.1103/PhysRevD.61.077302
Abstract: The recent results on the CP violating parameters Re(e'/e) and \Delta\phi = \phi_{00}-\phi_{+-} reported by the KTeV Collaboration are analyzed with a view to constrain CP, T and CPT violations in a decay process. Combining with some relevant data compiled by the Particle Data Group, we find Re(e_2-e_0) = (0.85 +- 3.11)*10^{-4} and Im(e_2-e_0) = (3.2 +- 0.7)*10^{-4}, where Re(e_I) and Im(e_I) represent respectively CP/CPT and CP/T violations in decay of K^0 and \bar{K^0} into a 2\pi state with isospin I.
Disk modelling by radiation-magnetohydrodynamic simulations
Mineshige S.,Ohsuga K.,Takeuchi S.
EPJ Web of Conferences , 2012, DOI: 10.1051/epjconf/20123906005
Abstract: Historically, various accretion models have been discussed under radially one-zone approximations. In such one-zone models, however, dynamical aspects of the accretion flow, such as internal circulation and outflows, have been totally neglected. Further, the disk viscosity is usually described by the phenomenological α-viscosity model. We, here, elucidate the theory of accretion flows and outflows based on our global, two-dimensional radiation-magnetohydrodynamic simulations, not relying on the α model. We have succeeded in producing three distinct states of accretion flow by controling only one parameter, a density normalization. Of particular importance is the presence of outflows in all three states. Several noteworthy features of the supercritical (or super-Eddington) accretion flows are found; that is, relativistic, collimated outflows (jets), and low-velocity, uncollimated outflows with clumpy structure. Observational implications are briefly discussed.
Clumpy Outflow from Supercritical Accretion Flows
S. Takeuchi,K. Ohsuga,S. Mineshige
Physics , 2013, DOI: 10.1093/pasj/65.4.88
Abstract: Significant fraction of matter in supercritical (or super-Eddington) accretion flow is blown away by radiation force, thus forming outflows, however, the properties of such radiation-driven outflows have been poorly understood. We have performed global two-dimensional radiaion-magnetohydrodynamic simulations of supercritical accretion flow onto a black hole with 10 or 10^8 solar masses in a large simulation box of 514 r_S x 514 r_S (with r_S being the Schwarzschild radius). We confirm that uncollimated outflows with velocities of 10 percents of the speed of light emerge from the innermost part of the accretion flow over wide angles of 10 - 50 degree from the disk rotation axis. Importantly, the outflows exhibit clumpy structure above heights of ~ 250 r_S. The typical size of the clumps is ~ 10 r_S, which corresponds to one optical depth, and their shapes are slightly elongated along the outflow direction. Since clumps start to form in the layer above which (upward) radiation force overcomes (downward) gravity force, Rayleigh-Taylor instability seems to be of primary cause. In addition, a radiation hydrodynamic instability, which arises when radiation funnels through radiation-pressure supported atmosphere, may also help forming clumps of one optical depth. Magnetic photon bubble instability seems not to be essential, since similar clumpy outflow structure is obtained in non-magnetic radiation-hydrodynamic simulations. Since the spatial covering factor of the clumps is estimated to be ~ 0.3 and since they are marginally optically thick, they will explain at least some of rapid light variations of active galactic nuclei. We further discuss a possibility of producing broad-line clouds by the clumpy outflow.
Radiation Hydrodynamic Instability in Plane-Parallel, Super-Eddington Atmosphere: A Mechanism for Clump Formation
S. Takeuchi,K. Ohsuga,S. Mineshige
Physics , 2014, DOI: 10.1093/pasj/psu011
Abstract: In order to understand the physical processes underlying clump formation in outflow from supercritical accretion flow, we performed two-dimensional radiation hydrodynamic (RHD) simulations. We focus our discussion on the nature of RHD instability in marginally optically thick, plane-parallel, super-Eddington atmosphere. Initially we set two-layered atmosphere with a density contrast of 100 exposed to strong, upward continuum-radiation force; the lower layer is denser than the upper one, condition for an RHD instability. We assume non-zero but negligible gravitational force, compared with the radiation force. We find that short wavelength perturbations first grow, followed by growth of longer wavelength patterns, which lead to the formation of clumpy structure. The typical size of clumps (clouds) corresponds to about one optical depth. An anti-correlation between the radiation pressure and the gas pressure is confirmed: this anti-correlation provides a damping mechanism of longer wavelength perturbations than the typical clump size. Matter and radiation energy densities are correlated. These features are exactly what we found in the radiation-magnetohydrodynamic (radiation-MHD) simulations of supercritical outflow.
A Novel Jet Model: Magnetically Collimated, Radiation-Pressure Driven Jet
S. Takeuchi,K. Ohsuga,S. Mineshige
Physics , 2010, DOI: 10.1093/pasj/62.5.L43
Abstract: Relativistic jets from compact objects are ubiquitous phenomena in the Unvierse, but their driving mechanism has been an enigmatic issue over many decades. Two basic models have been extensively discussed: magnetohydrodynamic (MHD) jets and radiation-hydrodynamic (RHD) jets. Currently, the former is more widely accepted, since magnetic field is expected to provide both the acceleration and collimation mechanisms, whereas radiation field cannot collimate outflow. Here, we propose a new type of jets, radiation-magnetohydrodynamic (RMHD) jets, based on our global RMHD simulation of luminous accretion flow onto a black hole shining above the Eddington luminosity. The RMHD jet can be accelerated up to the relativistic speed by the radiation-pressure force and is collimated by the Lorentz force of a magnetic tower, inflated magnetic structure made by toroidal magnetic field lines accumulated around the black hole, though radiation energy greatly dominates over magnetic energy. This magnetic tower is collimated by a geometrically thick accretion flow supported by radiation-pressure force. This type of jet may explain relativistic jets from Galactic microquasars, appearing at high luminosities.
Ultraviolet-resonance femtosecond stimulated Raman study of the initial events in photoreceptor chromophore
Takeuchi S.,Kuramochi H.,Tahara T.
EPJ Web of Conferences , 2013, DOI: 10.1051/epjconf/20134108002
Abstract: Newly-developed ultraviolet-resonance femtosecond stimulated-Raman spectroscopy was utilized to study the initial structural evolution of photoactive yellow protein chromophore in solution. The obtained spectra changed drastically within 1 ps, demonstrating rapid in-plane deformations of the chromophore.
Indirect Probes of New Physics
J. L. Hewett,T. Takeuchi,S. Thomas
Physics , 1996,
Abstract: We summarize the indirect effects of new physics in a variety of processes. We consider precision electroweak measurements, the $g-2$ of the muon, rare decays, meson mixing, CP violation, lepton number violating interactions, double beta decay, and the electric dipole moments of atoms, molecules, and the neutron. We include discussions of both model independent and dependent analyses where applicable.
Page 1 /326283
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.