1,544 research outputs found
Whole body counter surveys of Miharu-town school children for four consecutive years after the Fukushima NPP accident
Comprehensive whole-body counter surveys of Miharu town school children have
been conducted for four consecutive years, in 2011-2014. This represents the
only long-term sampling-bias-free study of its type conducted after the
Fukushima Dai-ichi accident. For the first time in 2014, a new device called
the Babyscan, which has a low Cs MDA of Bq/body, was used to
screen the children shorter than 130 cm. No child in this group was found to
have detectable level of radiocesium. Using the MDAs, upper limits of daily
intake of radiocesium were estimated for each child. For those screened with
the Babyscan, the upper intake limits were found to be <1 Bq/day for
Cs. Analysis of a questionnaire filled out by the children's parents
regarding their food and water consumption shows that the majority of Miharu
children regularly consume local and/or home-grown rice and vegetables. This
however does not increase the body burden.Comment: 11 pages, 10 figure
Momentum-Dependent Hybridization Gap and dispersive in-gap state of The Kondo Semiconductor SmB6
We report the temperature-dependent three-dimensional angle-resolved
photoemission spectra of the Kondo semiconductor SmB. We found a difference
in the temperature dependence of the peaks at the X and points, due to
hybridization between the Sm 5d conduction band and the nearly localized Sm 4f
state. The peak intensity at the X point has the same temperature dependence as
the valence transition below 120 K, while that at the point is
consistent with the magnetic excitation at Q=(0.5,0.5,0.5) below 30 K. This
suggests that the hybridization with the valence transition mainly occurs at
the X point, and the initial state of the magnetic excitation is located at the
point.Comment: 5 pages, 3 figure
Isotropic photonic band gap and anisotropic structures in transmission spectra of two-dimensional 5-fold and 8-fold symmetric quasiperiodic photonic crystals
We measured and calculated transmission spectra of two-dimensional
quasiperiodic photonic crystals (PCs) based on a 5-fold (Penrose) or 8-fold
(octagonal) symmetric quasiperiodic pattern. The photonic crystal consisted of
dielectric cylindrical rods in air placed normal to the basal plane on vertices
of tiles composing the quasiperiodic pattern. An isotropic photonic band gap
(PBG) appeared in the TM mode, where electric fields were parallel to the rods,
even when the real part of a dielectric constant of the rod was as small as
2.4. An isotropic PBG-like dip was seen in tiny Penrose and octagonal PCs with
only 6 and 9 rods, respectively. These results indicate that local multiple
light scattering within the tiny PC plays an important role in the PBG
formation. Besides the isotropic PBG, we found dips depending on the incident
angle of the light. This is the first report of anisotropic structures clearly
observed in transmission spectra of quasiperiodic PCs. Based on rod-number and
rod-arrangement dependence, it is thought that the shapes and positions of the
anisotropic dips are determined by global multiple light scattering covering
the whole system. In contrast to the isotropic PBG due to local light
scattering, we could not find any PBGs due to global light scattering even
though we studied transmission spectra of a huge Penrose PC with 466 rods.Comment: One tex file for manuscript and 12 PNG files for figures consisting
of Fig.1a-d, 2,3, ...
Electronic-Structure-Driven Magnetic Ordering in a Kondo Semiconductor CeOs2Al10
We report the anisotropic changes in the electronic structure of a Kondo
semiconductor CeOsAl across an anomalous antiferromagnetic ordering
temperature () of 29 K, using optical conductivity spectra. The spectra
along the - and -axes indicate that a - hybridization gap emerges
from a higher temperature continuously across . Along the b-axis, on the
other hand, a different energy gap with a peak at 20 meV appears below 39 K,
which is higher temperature than , because of structural distortion. The
onset of the energy gap becomes visible below . Our observation reveals
that the electronic structure as well as the energy gap opening along the
b-axis due to the structural distortion induces antiferromagnetic ordering
below .Comment: 4 pages, 4 figure
Electronic inhomogeneity in EuO: Possibility of magnetic polaron states
We have observed the spatial inhomogeneity of the electronic structure of a
single-crystalline electron-doped EuO thin film with ferromagnetic ordering by
employing infrared magneto-optical imaging with synchrotron radiation. The
uniform paramagnetic electronic structure changes to a uniform ferromagnetic
structure via an inhomogeneous state with decreasing temperature and increasing
magnetic field slightly above the ordering temperature. One possibility of the
origin of the inhomogeneity is the appearance of magnetic polaron states.Comment: 4 pages, 3 figure
Spatiotemporal Evolution of Recurrent Slow Slip Events Along the Southern Ryukyu Subduction Zone, Japan, From 2010 to 2013
Extracting Important Tweets for News Writers using Recurrent Neural Network with Attention Mechanism and Multi-task Learning
Stability regions of discrete linear periodic systems with delayed feedback controls
We propose a geometric method to determine the stability region of the zero solution of a linear periodic difference equation via the delayed feedback control (briefly, DFC) with the commuting feedback gain. For the equation, our method is more effective than the Jury criterion. First, we give a relationship, named the C-map theorem, between the characteristic multipliers of an original equation and those of the equation via DFC. Next, we show the existence and m-starlike property, defined in this paper, of an m-closed curve induced from the C-map. Using this result, we prove that the region enclosed by the m-closed curve is the stability region of the zero solution of the equation via DFC.Dohan Kim was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean Government (MSIT) (No. 2018R1D1A1B07041273 and No. 2021R1A2C1092945
Kondo-like behaviors in magnetic and thermal properties of single crystal Tm5Si2Ge2
We grew the single crystal of stoichiometric Tm5Si2.0Ge2.0 using a Bridgeman
method and performed XRD, EDS, magnetization, ac and dc magnetic
susceptibilities, specific heat, electrical resistivity and XPS experiments. It
crystallizes in orthorhombic Sm5Ge4-type structure. The mean valence of Tm ions
in Tm5Si2.0Ge2.0 is almost trivalent. The 4f states is split by the crystalline
electric field. The ground state exhibits the long range antiferromagnetic
order with the ferromagnetically coupled magnetic moments in the ac plane below
8.01 K, while the exited states exhibit the reduction of magnetic moment and
magnetic entropy and -log T-behaviors observed in Kondo materials.Comment: 8 pages, 13 figure
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