4,050 research outputs found
Microscopic origin of bipolar resistive switching of nanoscale titanium oxide thin films
We report a direct observation of the microscopic origin of the bipolar
resistive switching behavior in nanoscale titanium oxide films. Through a
high-resolution transmission electron microscopy, an analytical TEM technique
using energy-filtering transmission electron microscopy and an in situ x-ray
photoelectron spectroscopy, we demonstrated that the oxygen ions piled up at
top interface by an oxidation-reduction reaction between the titanium oxide
layer and the top Al metal electrode. We also found that the drift of oxygen
ions during the on/off switching induced the bipolar resistive switching in the
titanium oxide thin films.Comment: 10 pages, 4 figure
Metal/graphene sheets as p-type transparent conducting electrodes in GaN light emitting diodes
We demonstrate the use of graphene based transparent sheets as a p-type current spreading layer in GaN light emitting diodes (LEDs). Very thin Ni/Au was inserted between graphene and p-type GaN to reduce contact resistance, which reduced contact resistance from similar to 5.5 to similar to 0.6 Omega/ cm(2), with no critical optical loss. As a result, LEDs with metal-graphene provided current spreading and injection into the p-type GaN layer, enabling three times enhanced electroluminescent intensity compared with those with graphene alone. We confirmed very strong blue light emission in a large area of the metal-graphene layer by analyzing image brightness.open281
Optimal Multilayer Adaptation of SVC Video over Heterogeneous Environments
Scalable video coding (SVC) is a new video coding format which provides scalability in three-dimensional (spatio-temporal-SNR) space. In this paper, we focus on the adaptation in SNR dimension. Usually, an SVC bitstream may contain multiple spatial layers, and each spatial layer may be enhanced by several FGS layers. To meet a bitrate constraint, the fine-grained scalability (FGS) data of different spatial layers can be truncated in various manners. However, the contributions of FGS layers to the overall/collective video quality are different. In this work, we propose an optimized framework to control the SNR scalability across multiple spatial layers. Our proposed framework has the flexibility in allocating the resource (i.e., bitrate) among spatial layers, where the overall quality is defined as a function of all spatial layers' qualities and can be modified on the fly
Anti-Inflammatory Effects of Bangpungtongsung-San, a Traditional Herbal Prescription
Bangpungtongsung-san (BPTS), a traditional oriental herbal prescription, is widely used for expelling wind, draining heat, and providing general improvement to the immune system. In this study, we investigated the effects of BPTS on induction of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), proinflammatory cytokines, nuclear factor-kappa B (NF-κB), and mitogen-activated protein kinases (MAPKs) in lipopolysaccharide- (LPS- ) stimulated Raw 264.7 cells, and on paw edema in rats. At concentrations of 0.5, 0.75, and 1 mg/mL, treatment with BPTS inhibited levels of expression of LPS-induced NF-κB and MAPKs (ERK, JNK, and p38) as well as production of proinflammatory mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) by LPS. These results suggest that BPTS may exert anti-inflammatory effects via reduction of proinflammatory mediators, including NO, PGE2, TNF-α, and IL-6 through suppression of the signaling pathways of NF-κB and MAPKs in LPS-induced macrophages. In addition, using the carrageenan-induced paw edema assay, an antiedema effect of BPTS was observed in rats. These findings may provide scientific evidence validating the use of BPTS in treatment of patients with heat syndrome in Korean oriental medicine
Electrical current suppression in Pd-doped vanadium pentoxide nanowires caused by reduction in PdO due to hydrogen exposure
Pd nanoparticle-doped vanadium pentoxide nanowires (Pd-VONs) were synthesized. Electrical current suppression was observed when the Pd-VON was exposed to hydrogen gas, which cannot be explained by the work function changes mentioned in previous report such as Pd-doped carbon nanotubes and SnO 2 nanowires. Using the x-ray photoelectron spectroscopy, we found that the reduction in PdO due to hydrogen exposure plays an important role in the current suppression of the Pd-VON.open4
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