478 research outputs found
Nucleon mean free path in nuclear matter based on nuclear Schwinger-Dyson formalism
A mean free path of nucleon moving through nuclear matter with kinetic energy
of more than 100MeV is formulated based on the bare vertex nuclear
Schwinger-Dyson (BNSD) method in the Walecka model. The self-energy which is
derived from the higher order diagrams more than the forth order includes the
Feynman part of propagator of energetic nucleon and grows up rapidly as an
increase of kinetic energy. To avoid too large growth of these diagrams, meson
propagators are modified by introducing some form factors to take account of a
internal structure of hadron. It is confirmed that the mean free path
calculated by the BNSD method agrees good with experimental data if a
reasonable form factor is chosen, i.e., a dipole (quadrupole) type of form
factor with a cut-off parameter about 750 MeV 1000 MeV (1200 MeV
1500 MeV)
Partially-disordered photonic-crystal thin films for enhanced and robust photovoltaics
We present a general framework for the design of thin-film photovoltaics
based on a partially-disordered photonic crystal that has both enhanced
absorption for light trapping and reduced sensitivity to the angle and
polarization of incident radiation. The absorption characteristics of different
lattice structures are investigated as an initial periodic structure is
gradually perturbed. We find that an optimal amount of disorder controllably
introduced into a multi-lattice photonic crystal causes the characteristic
narrow-band, resonant peaks to be broadened resulting in a device with enhanced
and robust performance ideal for typical operating conditions of photovoltaic
applications.Comment: 5 pages, 4 figure
Vacuum Effects and Compressional Properties of Nuclear Matter in Cutoff Field Theory
Including the vacuum effects, the compressional properties of nuclear matter
are studied in the cutoff field theory. Under the Hartree approximation, the
low-energy effective Lagrangian is derived in the framework of the
renormalization group methods. The coefficients are determined in a way where
the physical results hardly depend on the value of the cutoff which is
conveniently introduced into the theory. It is shown that, to reproduce the
empirical data of the nucleus incompressibility, the compressibility of the
nuclear matter is favorable to be 250350MeV.Comment: PACS numbers, 21.65.+
Effects of specific cultivar usage and preparation methods in Japanese potato starches.
Potato starch is one of the important agricultural products in Hokkaido, the northernmost and second largest island of Japan. The aim of this study was to evaluate the effects of cultivars and starch preparation methods on the quality parameters of Japanese potato starch. Potato starches from four cultivars, Hokkaikogane, Eniwa, Benimaru and Norin No. 1, grown over a period of several years in Hokkaido were used. The starches produced with tap water in a local starch factory and with distilled water in a laboratory were investigated for phosphorus content, median granule size and peak viscosity and breakdown as determined with a Rapid Visco Analyzer (RVA). Among the starch samples used in this study, significant differences were observed across starch quality parameters. We investigated the differences in quality parameters as an effect of individual cultivars. The starch median granule size among potato cultivars varied in the following order: Benimaru (43.1 μm) > Hokkaikogane (39.1 μm) ≈Eniwa (38.2 μm) > Norin No. 1 (33.9 μm). We found that starches of Hokkaikogane and Eniwa, both with a measurably higher phosphorus content, displayed significantly higher peak viscosity and breakdown than those of Benimaru and Norin No. 1. We also examined the effect that the preparation method has on starch quality parameters within the same potato cultivar. We found that the starch preparation method had a little or no influence on phosphorus content. Median granule size was also completely independent on the preparation method. The RVA evaluation revealed that, even within the same cultivar, starches produced in a factory showed lower peak viscosity and breakdown than those produced in a laboratory
Measurement of AGN dust extinction based on the near-infrared flux variability of WISE data
We present the measurement of the line-of-sight extinction of the dusty torus
for a large number of obscured active galactic nuclei (AGNs) based on the
reddening of the colour of the variable flux component in near-infrared (NIR)
wavelengths. We collected long-term monitoring data by for 513 local AGNs catalogued by the
BAT AGN Spectroscopic Survey (BASS) and found that the
multi-epoch NIR flux data in two different bands (WISE and ) are
tightly correlated for more than 90% of the targets. The flux variation
gradient (FVG) in the and bands was derived by applying linear
regression analysis, and we reported that those for unobscured AGNs fall in a
relatively narrow range, whereas those for obscured AGNs are distributed in a
redder and broader range. The AGN's line-of-sight dust extinction () is
calculated using the amount of the reddening in the FVG and is compared with
the neutral hydrogen column density () of the BASS catalogue. We
found that the ratios of obscured AGNs are greater than those
of the Galactic diffuse interstellar medium (ISM) and are distributed with a
large scatter by at most two orders of magnitude. Furthermore, we found that
the lower envelope of the of obscured AGNs is comparable to
the Galactic diffuse ISM. These properties of the can be
explained by increase in the attributed to the dust-free gas
clouds covering the line of sight in the broad-line region.Comment: 11 pages, 7 figures, published in MNRA
Effective meson masses, effective meson-nucleon couplings and neutron star radii
Using the generalized mean field theory, we have studied the relation among
the effective meson masses, the effective meson-nucleon couplings and the
equation of state (EOS) in asymmetric nuclear matter. If the effective
omega-meson mass becomes smaller at high density, the EOS becomes stiffer.
However, if we require that the omega-meson mean field is proportional to the
baryon density, the effective omega-nucleon coupling automatically becomes
smaller at the same time as the effective omega-meson mass becomes smaller.
Consequently, the EOS becomes softer. A similar relation is found for the
effective rho-meson mass and the effective rho-nucleon coupling. We have also
studied the relation among the effective meson masses, the effective
meson-nucleon couplings and a radius R of a neutron star. The R depends
somewhat on the value of the effective omega-meson mass and the effective
omega-nucleon coupling.Comment: 29pages, 24 figure
Quark condensate in nuclear matter based on Nuclear Schwinger-Dyson formalism
The effects of higher order corrections of ring diagrams for the quark
condensate are studied by using the bare vertex Nuclear Schwinger Dyson
formalism based on - model. At the high density the quark
condensate is reduced by the higher order contribution of ring diagrams more
than the mean field theory or the Hartree-Fock
Factors affecting the digestibility of raw and gelatinized potato starches.
The enzymatic digestibilities of raw and gelatinized starches in various potato starches, as well as sweet potato, cassava, and yam starches, were estimated, along with other starch properties, such as the phosphorus content, median granule size, and rapid visco analyzer (RVA) pasting properties. Furthermore, correlation coefficients were calculated between the hydrolysis rates (HR) by amylase and other starch quality parameters. A larger granule size was closely associated with a lower HR in raw starch, while the HR in gelatinized starch did not correlate with the median granule size. An increase in phosphorus content resulted in a definitely lower HR in raw starch and tended to decrease the HR in gelatinized starch for the composite of potato and other starches. In contrast, no correlation coefficients of the phosphorus content with the HRs in raw and gelatinized starches were observed within potato starches. Starches with higher peak viscosity and breakdown showed a lower HR in raw starch, while few or no effects of these RVA parameters on the HR in gelatinized starch were observed for the composite of potato and other starches or among potato starches, respectively
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