1,521 research outputs found
Influence of Mg Deficiency on the Superconductivity in MgB2 Thin Films Grown by using HPCVD
The effects of Mg deficiency in MgB2 films grown by using hybrid
physical-chemical vapor deposition were investigated after vacuum annealing at
various temperatures. High-quality MgB2 films grown on c-cut Al2O3 substrates
with different superconducting transition temperatures (Tc) of 40.2 and 41 K
were used in this study. As the annealing temperature was increased from 200 to
800 C, the Mg contents in the MgB2 films systemically decreased, but the Tc's
did not change, within 0.12 K, until the annealing temperature reached 700 C.
For MgB2 films annealed at 800 C for 30 min, however, no superconductivity was
observed, and the temperature dependence of the resistivity showed a
semiconducting behavior. We also found that the residual resistivity ratio
decreased with increasing annealing temperature.Comment: 7 pages including 4 figure
Potassium-doped BaFe2As2 superconducting thin films with a transition temperature of 40 K
We report the growth of potassium-doped BaFe2As2 thin films, where the major
charge carriers are holes, on Al2O3 (0001) and LaAlO3 (001) substrates by using
an ex-situ pulsed laser deposition technique. The measured Tc's are 40 and 39 K
for the films grown on Al2O3 and LaAlO3, respectively and diamagnetism
indicates that the films have good bulk superconducting properties below 36 and
30 K, respectively. The X-ray diffraction patterns for both films indicated a
preferred c-axis orientation, regardless of the substrate structures of LaAlO3
and Al2O3. The upper critical field at zero temperature was estimated to be
about 155 T.Comment: 6 pages including 3 figure
In-situ fabrication of cobalt-doped SrFe2As2 thin films by using pulsed laser deposition with excimer laser
The remarkably high superconducting transition temperature and upper critical
field of iron(Fe)-based layered superconductors, despite ferromagnetic material
base, open the prospect for superconducting electronics. However, success in
superconducting electronics has been limited because of difficulties in
fabricating high-quality thin films. We report the growth of high-quality
c-axis-oriented cobalt(Co)-doped SrFe2As2 thin films with bulk
superconductivity by using an in-situ pulsed laser deposition technique with a
248-nm-wavelength KrF excimer laser and an arsenic(As)-rich phase target. The
temperature and field dependences of the magnetization showing strong
diamagnetism and transport critical current density with superior Jc-H
performance are reported. These results provide necessary information for
practical applications of Fe-based superconductors.Comment: 8 pages, 3figures. to be published at Appl. Phys. Let
Co-occurrence matrix analysis-based semi-supervised training for object detection
One of the most important factors in training object recognition networks
using convolutional neural networks (CNNs) is the provision of annotated data
accompanying human judgment. Particularly, in object detection or semantic
segmentation, the annotation process requires considerable human effort. In
this paper, we propose a semi-supervised learning (SSL)-based training
methodology for object detection, which makes use of automatic labeling of
un-annotated data by applying a network previously trained from an annotated
dataset. Because an inferred label by the trained network is dependent on the
learned parameters, it is often meaningless for re-training the network. To
transfer a valuable inferred label to the unlabeled data, we propose a
re-alignment method based on co-occurrence matrix analysis that takes into
account one-hot-vector encoding of the estimated label and the correlation
between the objects in the image. We used an MS-COCO detection dataset to
verify the performance of the proposed SSL method and deformable neural
networks (D-ConvNets) as an object detector for basic training. The performance
of the existing state-of-the-art detectors (DConvNets, YOLO v2, and single shot
multi-box detector (SSD)) can be improved by the proposed SSL method without
using the additional model parameter or modifying the network architecture.Comment: Submitted to International Conference on Image Processing (ICIP) 201
A Case of Korean Ginseng-Induced Anaphylaxis Confirmed by Open Oral Challenge and Basophil Activation Test
Two case reports discussing Korean ginseng-induced allergic reactions have been published; both were inhalation-induced respiratory allergies in occupational settings. In this report we discuss the first case of anaphylaxis that developed after an oral intake of ginseng, confirmed by an open oral challenge, a skin prick test (SPT), and a basophil activation test (BAT). A 44-year-old man experienced rhinorrhea and nasal stiffness, followed by respiratory difficulty with wheeze and abdominal pain 10 minutes after oral intake of fresh ginseng. He had suffered from episodes of allergic rhinitis during the spring season for several years. Upon presentation, a physical examination, chest radiograph, and routine laboratory tests were unremarkable. Total serum IgE level was 41 IU/mL. The SPT results showed strong positive responses to alder, birch pollens, and ginseng extracts (1:500 w/v). The methacholine bronchial challenge test revealed a positive result at PC20 of 5.83 mg/mL. The open oral challenge was performed using 50 g of fresh ginseng and showed immediate onset of facial flushing, cough, respiratory difficulty with wheeze, and abdominal pain combined with a significant decrease in FEV1 levels (54% from the baseline). Serum-specific IgE and IgG4 antibodies were not detectable by enzyme-linked immunosorbent assay. BAT showed a remarkable increase in the expression of CD203c and CD63 with the addition of ginseng extract in a dose-dependent manner, while no changes were noted in the controls. In conclusion, oral intake of Korean ginseng could induce anaphylaxis, which is mediated by non-IgE-dependent direct activation of basophil/mast cells
Optical spectroscopic investigation on the coupling of electronic and magnetic structure in multiferroic hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films
We investigated the effects of temperature and magnetic field on the
electronic structure of hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films
using optical spectroscopy. As the magnetic ordering of the system was
disturbed, a systematic change in the electronic structure was commonly
identified in this series. The optical absorption peak near 1.7 eV showed an
unexpectedly large shift of more than 150 meV from 300 K to 15 K, accompanied
by an anomaly of the shift at the Neel temperature. The magnetic field
dependent measurement clearly revealed a sizable shift of the corresponding
peak when a high magnetic field was applied. Our findings indicated strong
coupling between the magnetic ordering and the electronic structure in the
multiferroic hexagonal RMnO3 compounds.Comment: 16 pages including 4 figure
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