3,387 research outputs found
Analytical result on the supercurrent through a superconductor/quantum-dot/superconductor junction
We present an analytical result for the supercurrent across a
superconductor/quantum-dot/superconductor junction. By converting the current
integration into a special contour integral, we can express the current as a
sum of the residues of poles. These poles are real and give a natural
definition of the Andreev bound states. We also use the exact result to explain
some features of the supercurrent transport behavior.Comment: 8 pages, 2 figure
Photon-assisted Fano Resonance and Corresponding Shot-Noise in a Quantum Dot
We have studied the Fano resonance in photon-assisted transport in a quantum
dot and calculated both the coherent current and spectral density of shot
noise. It is predicted, for the first time, that the shape of Fano profile will
also appear in satellite peaks. It is found that the variations of Fano
profiles with the strengths of nonresonant transmissions are not synchronous in
absorption and emission sidebands. The effect of interference on
photon-assisted pumped current has been also investigated. We further predict
the current and spectral density of shot noise as a function of the phase,
which exhibits an intrinsic property of resonant and nonresonant channels in
the structures.Comment: 4 pages, 5 figure
Electron dephasing in homogeneous and inhomogeneous indium tin oxide thin films
The electron dephasing processes in two-dimensional homogeneous and
inhomogeneous indium tin oxide thin films have been investigated in a wide
temperature range 0.3--90 K. We found that the small-energy-transfer
electron-electron (-) scattering process dominated the dephasing from a
few K to several tens K. At higher temperatures, a crossover to the
large-energy-transfer - scattering process was observed. Below about 1--2
K, the dephasing time revealed a very weak temperature
dependence, which intriguingly scaled approximately with the inverse of the
electron diffusion constant , i.e., . Theoretical implications of our results are discussed. The reason
why the electron-phonon relaxation rate is negligibly weak in this
low-carrier-concentration material is presented.Comment: 10 pages, 7 figure
Probing onset of strong localization and electron-electron interactions with the presence of direct insulator-quantum Hall transition
We have performed low-temperature transport measurements on a disordered
two-dimensional electron system (2DES). Features of the strong localization
leading to the quantum Hall effect are observed after the 2DES undergoes a
direct insulator-quantum Hall transition with increasing the perpendicular
magnetic field. However, such a transition does not correspond to the onset of
strong localization. The temperature dependences of the Hall resistivity and
Hall conductivity reveal the importance of the electron-electron interaction
effects to the observed transition in our study.Comment: 9 pages, 4 figure
Insulator, semiclassical oscillations and quantum Hall liquids at low magnetic fields
Magneto-transport measurements are performed on two-dimensional GaAs electron
systems to probe the quantum Hall (QH) effect at low magnetic fields.
Oscillations following the Shubnikov-de Haas (SdH) formula are observed in the
transition from the insulator to QH liquid when the observed almost
temperature-independent Hall slope indicates insignificant interaction
correction. Our study shows that the existence of SdH oscillations in such a
transition can be understood based on the non-interacting model.Comment: 17 page
Salient Objects in Clutter: Bringing Salient Object Detection to the Foreground
We provide a comprehensive evaluation of salient object detection (SOD)
models. Our analysis identifies a serious design bias of existing SOD datasets
which assumes that each image contains at least one clearly outstanding salient
object in low clutter. The design bias has led to a saturated high performance
for state-of-the-art SOD models when evaluated on existing datasets. The
models, however, still perform far from being satisfactory when applied to
real-world daily scenes. Based on our analyses, we first identify 7 crucial
aspects that a comprehensive and balanced dataset should fulfill. Then, we
propose a new high quality dataset and update the previous saliency benchmark.
Specifically, our SOC (Salient Objects in Clutter) dataset, includes images
with salient and non-salient objects from daily object categories. Beyond
object category annotations, each salient image is accompanied by attributes
that reflect common challenges in real-world scenes. Finally, we report
attribute-based performance assessment on our dataset.Comment: ECCV 201
Successful treatment of methemoglobinemia in an elderly couple with severe cyanosis: two case reports
INTRODUCTION: Methemoglobinemia should be considered in all cyanotic patients who remain unresponsive to oxygen therapy. Rapid diagnosis is very important in emergency cases. Here, we present the cases of two patients, a married couple, admitted to our hospital with methemoglobinemia after exposure to sodium nitrite. CASE PRESENTATION: Two patients, a married couple, presented with methemoglobinemia. The 72-year-old Taiwanese man and 68-year-old Taiwanese woman were referred to our hospital with dizziness and tachypnea. On examination, their mucous membranes were cyanotic, and their blood samples showed the classic ‘chocolate brown’ appearance. The man also reported having experienced twitching of his right arm for a few minutes before arrival at the hospital. The symptoms of both patients failed to improve in response to supplemental oxygen delivered via oxygen masks, although the arterial blood gas data of these patients were normal and their pulse oximetry showed oxyhemoglobin levels of approximately 85%. A carbon monoxide-oximeter showed that the man’s methemoglobin concentration was 48.3%, and the woman’s was 36.4%. Methylene blue (100mg) was administered intravenously to both patients, and their symptoms improved dramatically. They were admitted to the intensive care unit and discharged three days later, without neurological sequelae. CONCLUSION: Severe methemoglobinemia is a life-threatening condition and, if untreated, may result in death. Early diagnosis and appropriate antidotal treatment are crucial in treating this emergency situation
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