5,056 research outputs found
KINEMATIC ANALYSIS OF LOWER LIMB IN FUTSAL BALL KICKING
The diameter of the futsal ball (200 mm) is smaller than that of the soccer ball by 20 mm, and the futsal ball also has lower resilience than the soccer ball. Because of these differences in the balls, it is thought that the kicking motions of futsal players are distinct from those of soccer players. No study has yet been conducted on the motion involved in kicking a futsal ball. The aim of this study was to clarify the difference between the motion involved in kicking the futsal ball with that involved in kicking the soccer ball
Efficient implementation of the nonequilibrium Green function method for electronic transport calculations
An efficient implementation of the nonequilibrium Green function (NEGF)
method combined with the density functional theory (DFT) using localized
pseudo-atomic orbitals (PAOs) is presented for electronic transport
calculations of a system connected with two leads under a finite bias voltage.
In the implementation, accurate and efficient methods are developed especially
for evaluation of the density matrix and treatment of boundaries between the
scattering region and the leads. Equilibrium and nonequilibrium contributions
in the density matrix are evaluated with very high precision by a contour
integration with a continued fraction representation of the Fermi-Dirac
function and by a simple quadratureon the real axis with a small imaginary
part, respectively. The Hartree potential is computed efficiently by a
combination of the two dimensional fast Fourier transform (FFT) and a finite
difference method, and the charge density near the boundaries is constructed
with a careful treatment to avoid the spurious scattering at the boundaries.
The efficiency of the implementation is demonstrated by rapid convergence
properties of the density matrix. In addition, as an illustration, our method
is applied for zigzag graphene nanoribbons, a Fe/MgO/Fe tunneling junction, and
a LaMnOSrMnO superlattice, demonstrating its applicability to a wide
variety of systems.Comment: 20 pages, 11 figure
Correlation of high energy muons with primary composition in extensive air shower
An experimental investigation of high energy muons above 200 GeV in extensive air showers has been made for studying high energy interaction and primary composition of cosmic rays of energies in the range 10 to the 14th power approx. 10 to the 15th power eV. The muon energies are estimated from the burst sizes initiated by the muons in the rock, which are measured by four layers of proportional counters, each of area 5 x 2.6 sq m, placed at 30 m.w.e. deep, Funasaka tunnel vertically below the air shower array. These results are compared with Monte Carlo simulations based on the scaling model and the fireball model for two primary compositions, all proton and mixed
Characterization of halogen-bridged binuclear metal complexes as hybridized two-band materials
We study the electronic structure of halogen-bridged binuclear metal (MMX)
complexes with a two-band Peierls-Hubbard model. Based on a symmetry argument,
various density-wave states are derived and characterized. The ground-state
phase diagram is drawn within the Hartree-Fock approximation, while the thermal
behavior is investigated using a quantum Monte Carlo method. All the
calculations conclude that a typical MMX compound Pt_2(CH_3CS_2)_4I should
indeed be regarded as a d-p-hybridized two-band material, where the oxidation
of the halogen ions must be observed even in the ground state, whereas another
MMX family (NH_4)_4[Pt_2(P_2O_5H_2)_4X] may be treated as single-band
materials.Comment: 16 pages, 11 figures embedded, to be published in Phys. Rev.
Evolution of superconductivity in LaO1-xFxBiS2 prepared by high pressure technique
Novel BiS2-based superconductors LaO1-xFxBiS2 prepared by the high pressure
synthesis technique were systematically studied. It was found that the high
pressure annealing strongly the lattice as compared to the LaO1-xFxBiS2 samples
prepared by conventional solid state reaction at ambient pressure. Bulk
superconductivity was observed within a wide F-concentration range of x = 0.2 ~
0.7. On the basis of those results, we have established a phase diagram of
LaO1-xFxBiS2.Comment: 11 pages, 6 figure
Fermiological Interpretation of Superconductivity/Non-superconductivity of FeTe_{1-x}Se_{x} Thin Crystal Determined by Quantum Oscillation Measurement
We have successfully observed quantum oscillation (QO) for FeTe_{1-x}Se_{x}.
QO measurements were performed using non-superconducting and superconducting
thin crystals of FeTe_{0.65}Se_{0.35} fabricated by the scotch-tape method. We
show that the Fermi surfaces (FS) of the non-superconducting crystal are in
good agreement with the rigid band shift model based on electron doping by
excess Fe while that of the superconducting crystal is in good agreement with
the calculated FS with no shift. From the FS comparison of both crystals, we
demonstrate the change of the cross-sectional area of the FS, suggesting that
the suppression of the FS nesting with the vector Q_{s} = (\pi, \pi) due to
excess Fe results in the disappearance of the superconductivity.Comment: 8 pages, 4 figure
An Electron/Ion Spectrometer with the Ability of Low Energy Electron Measurement for Fast Ignition Experiment
An electron energy spectrometer (ESM) is one of the most fundamental diagnostics in the fast ignition experiment. It is necessary to observe the spectra down to a low energy range in order to obtain the accurate deposition efficiency toward the core. Here, we realize the suitable ESM by using a ferrite magnet with a moderate magnetic field of 0.3 T and a rectangular magnetic circuit covered with a steel plate in the inlet side
Broken-symmetry-adapted Green function theory of condensed matter systems:towards a vector spin-density-functional theory
The group theory framework developed by Fukutome for a systematic analysis of
the various broken symmetry types of Hartree-Fock solutions exhibiting spin
structures is here extended to the general many body context using spinor-Green
function formalism for describing magnetic systems. Consequences of this theory
are discussed for examining the magnetism of itinerant electrons in nanometric
systems of current interest as well as bulk systems where a vector spin-density
form is required, by specializing our work to spin-density-functional
formalism. We also formulate the linear response theory for such a system and
compare and contrast them with the recent results obtained for localized
electron systems. The various phenomenological treatments of itinerant magnetic
systems are here unified in this group-theoretical description.Comment: 17 page
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