634 research outputs found
Prevention of drowsy driving by means of warning sound
Traffic accidents occur due to inattentive driving such as drowsy driving. A variety of support systems that make an attempt to prevent inattentive driving are under development. The development of a system to prevent drowsy driving using auditory or tactile alarm system is undertaken. It is essential to detect the low arousal state and warn drivers of such a state so that drowsy can be prevented. EEG (Electroencephalography) was used to evaluate how an arousal level degraded with time for eight participants under a low arousal level. Mean power frequency (MPF) was calculated to evaluate an arousal level. The value of MPF was compared between high and low arousal levels. The difference of arousal effect among four warning sounds was examined. As a result, there was no significant difference of arousal effect among four alarm sounds. The alarm sound was found to temporarily heighten participants' arousal level
Higgs response and pair condensation energy in superfluid nuclei
The pairing correlation in nuclei causes a characteristic excitation, known
as the pair vibration, which is populated by the pair transfer reactions. Here
we introduce a new method of characterizing the pair vibration by employing an
analogy to the Higgs mode, which emerges in infinite superconducting/superfluid
systems as a collective vibrational mode associated with the amplitude
oscillation of the Cooper pair condensate. The idea is formulated by defining a
pair-transfer probe, the Higgs operator, and then describing the linear
response and the strength function to this probe. We will show that the pair
condensation energy in nuclei can be extracted with use of the strength sum and
the static polarizability of the Higgs response. In order to demonstrate and
validate the method, we perform for Sn isotopes numerical analysis based the
quasi-particle random phase approximation to the Skyrme-Hartree-Fock-Bogoliubov
model. We discuss a possibility to apply this new scheme to pair transfer
experiment.Comment: 31 pages, 9 figure
^{31}P and ^{75}As NMR evidence for a residual density of states at zero energy in superconducting BaFe_2(As_{0.67}P_{0.33})_2
^{31}P and ^{75}As NMR measurements were performed in superconducting
BaFe_2(As_{0.67}P_{0.33})_2 with T_c = 30 K. The nuclear-spin-lattice
relaxation rate T_1^{-1} and the Knight shift in the normal state indicate the
development of antiferromagnetic fluctuations, and T_1^{-1} in the
superconducting (SC) state decreases without a coherence peak just below T_c,
as observed in (Ba_{1-x}K_{x})Fe_2As_2. In contrast to other iron arsenide
superconductors, the T_1^{-1} \propto T behavior is observed below 4K,
indicating the presence of a residual density of states at zero energy. Our
results suggest that strikingly different SC gaps appear in
BaFe_2(As_{1-x}P_{x})_2 despite a comparable T_c value, an analogous phase
diagram, and similar Fermi surfaces to (Ba_{1-x}K_{x})Fe_2As_2.Comment: 4 pages, 5 figure
Magnetic properties of epitaxial FeO films with various crystal orientations and TMR effect in room temperature
FeO is a ferrimagnetic spinel ferrite that exhibits electric
conductivity at room temperature (RT). Although the material has been predicted
to be a half metal according to ab-initio calculations, magnetic tunnel
junctions (MTJs) with FeO electrodes have demonstrated a small tunnel
magnetoresistance effect. Not even the sign of the TMR ratio has been
experimentally established. Here, we report on the magnetic properties of
epitaxial FeO films with various crystal orientations. The films
exhibited apparent crystal orientation dependence on hysteresis curves. In
particular, FeO(110) films exhibited in-plane uniaxial magnetic
anisotropy. With respect to the squareness of hysteresis, FeO (111)
demonstrated the largest squareness. Furthermore, we fabricated MTJs with
FeO(110) electrodes, and obtained an TMR effect of -12\% at RT. The
negative TMR ratio corresponded to the negative spin polarization of
FeO predicted from band calculations
Improving efficiency of the path optimization method for a gauge theory
We investigate efficiency of a gauge-covariant neural network and an
approximation of the Jacobian in optimizing the complexified integration path
toward evading the sign problem in lattice field theories. For the construction
of the complexified integration path, we employ the path optimization method.
The -dimensional gauge theory with the complex gauge coupling
constant is used as a laboratory to evaluate the efficiency. It is found that
the gauge-covariant neural network, which is composed of the Stout-like
smearing, can enhance the average phase factor, as the gauge-invariant input
does. For the approximation of the Jacobian, we test the most drastic case in
which we perfectly drop the Jacobian during the learning process. It reduces
the numerical cost of the Jacobian calculation from to , where means the number of degrees of freedom of the theory. The
path optimization using this Jacobian approximation still enhances the average
phase factor at expense of a slight increase of the statistical error.Comment: 8 pages, 5 figures; accepted versio
Bright and highly valley polarized trions in chemically doped monolayer MoS₂
We demonstrate the effect of p-type dopant F₄TCNQ molecular adsorption on the photoluminescence (PL) and valley polarization properties of trions in monolayer (1L) MoS₂ at 15 K using a spatial PL mapping method. Trion PL intensity considerably increased after the treatment, which was attributed to the extended trion nonradiative lifetime (~70 ps). Trion valley polarization as high as 0.75 showed a negligible decrease after the chemical treatment, as is the manifestation of a long trion valley lifetime of more than nanoseconds order. The results suggest that this method will be useful for future optovalleytronics applications of these materials
Impact of noncontrast PCI for ACS
Purpose : Contrast-induced acute kidney injury (CI-AKI) is one of the common serious complications of percutaneous coronary intervention (PCI) in patients with acute coronary syndrome (ACS). This study aimed to assess the significance of noncontrast strategy in the setting of ACS. Methods : CI-AKI was defined as an increase in serum creatinine of ≥ 0.5 mg / dL or ≥ 1.25 times from the baseline. One-year worsening renal function (WRF) was defined as an increase of ≥ 0.3 mg / dL in serum creatinine from the baseline after PCI. Results : Of 250 ACS patients, 81 were treated with noncontrast PCI. The average doses of contrast medium in the noncontrast and conventional groups were 17 (9–22) ml and 150 (120–200) ml, respectively. CI-AKI was observed in 4 patients (5%) in the noncontrast group and 29 patients (17%) in the conventional group. Noncontrast PCI was associated with a lower incidence of CI-AKI (adjusted odds ratio, 0.26 ; 95% confidence interval [CI], 0.08–0.82). The bootstrap method and inverse probability weighting led to similar results. CI-AKI was associated with a higher incidence of 1-year WRF (adjusted hazard ratio, 2.30 ; 95% CI, 1.12–4.69), while noncontrast PCI was not. Conclusions : Noncontrast PCI was associated with the lower incidence of CI-AKI in ACS patients
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