384 research outputs found
Steady state properties of a driven granular medium
We study a two-dimensional granular system where external driving force is
applied to each particle in the system in such a way that the system is driven
into a steady state by balancing the energy input and the dissipation due to
inelastic collision between particles. The velocities of the particles in the
steady state satisfy the Maxwellian distribution. We measure the
density-density correlation and the velocity-velocity correlation functions in
the steady state and find that they are of power-law scaling forms. The
locations of collision events are observed to be time-correlated and such a
correlation is described by another power-law form. We also find that the
dissipated energy obeys a power-law distribution. These results indicate that
the system evolves into a critical state where there are neither characteristic
spatial nor temporal scales in the correlation functions. A test particle
exhibits an anomalous diffusion which is apparently similar to the Richardson
law in a three-dimensional turbulent flow.Comment: REVTEX, submitted to Phys. Rev.
Primordial Neutrinos, Cosmological Perturbations in Interacting Dark-Energy Model: CMB and LSS
We present cosmological perturbation theory in neutrinos probe interacting
dark-energy models, and calculate cosmic microwave background anisotropies and
matter power spectrum. In these models, the evolution of the mass of neutrinos
is determined by the quintessence scalar field, which is responsible for the
cosmic acceleration today. We consider several types of scalar field potentials
and put constraints on the coupling parameter between neutrinos and dark
energy. Assuming the flatness of the universe, the constraint we can derive
from the current observation is at the 95 % confidence
level for the sum over three species of neutrinos. We also discuss on the
stability issue of the our model and on the impact of the scattering term in
Boltzmann equation from the mass-varying neutrinos.Comment: 26 pages Revtex, 11 figures, Add new contents and reference
Neutrino Mass Bounds from Neutrinoless Double Beta Decays and Large Scale Structures
We investigate the way how the total mass sum of neutrinos can be constrained
from the neutrinoless double beta decay and cosmological probes with cosmic
microwave background (WMAP 3-year results), large scale structures including
2dFGRS and SDSS data sets. First we discuss, in brief, on the current status of
neutrino mass bounds from neutrino beta decays and cosmic constrain within the
flat model. In addition, we explore the interacting neutrino
dark-energy model, where the evolution of neutrino masses is determined by
quintessence scalar filed, which is responsable for cosmic acceleration today.
Assuming the flatness of the universe, the constraint we can derive from the
current observation is eV at the 95 % confidence level,
which is consistent with eV in the flat
model. Finally we discuss the future prospect of the neutrino mass bound with
weak-lensing effects.Comment: Latex 12 pages, 3 figures, correct typos and add new reference
Estimation of Machine Parameters in Superconducting Transformer using Differential Evolution
To analyze the inrush current in a superconducting transformer, the machine parameters for the transformer were estimated from the measured current using a search algorithm. To address the large rising edge error in estimations performed using a genetic algorithm (GA), a differential evolution (DE) was used in this study. As a result, the estimated time was reduced to about 1/10 that obtained with GA, and the evaluation value indicating the difference between the measured value and the estimated value was reduced to about 1/2. Thus, it was possible to estimate with higher accuracy by using DE.32nd International Symposium on Superconductivity (ISS2019), 3-5 December, 2019, Kyoto, Japa
Changes in hepatitis C virus antibody titer and viral RNA load in non-Hodgkin's lymphoma patients after rituximab chemotherapy
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