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101.
B Jang M Park OB Chae S Park Y Kim SM Oh Y Piao T Hyeon 《Journal of the American Chemical Society》2012,134(36):15010-15015
Extensive applications of rechargeable lithium-ion batteries (LIBs) to various portable electronic devices and hybrid electric vehicles result in the increasing demand for the development of electrode materials with improved electrochemical performance including high energy, power density, and excellent cyclability, while maintaining low production cost. Here, we present a direct synthesis of ferrite/carbon hybrid nanosheets for high performance lithium-ion battery anodes. Uniform-sized ferrite nanocrystals and carbon materials were synthesized simultaneously through a single heating procedure using metal-oleate complex as the precursors for both ferrite and carbon. 2-D nanostructures were obtained by using sodium sulfate salt powder as a sacrificial template. The 2-D ferrite/carbon nanocomposites exhibited excellent cycling stability and rate performance derived from 2-D nanostructural characteristics. The synthetic procedure is simple, inexpensive, and scalable for mass production, and the highly ordered 2-D structure of these nanocomposites has great potential for many future applications. 相似文献
102.
Mohammad Shoyaib M. Abdullah-Al-Wadud Oksam Chae 《International Journal of Approximate Reasoning》2012,53(4):636-659
Skin detection is an important step for a wide range of research related to computer vision and image processing and several methods have already been proposed to solve this problem. However, most of these methods suffer from accuracy and reliability problems when they are applied to a variety of images obtained under different conditions. Performance degrades further when fewer training data are available. Besides these issues, some methods require long training times and a significant amount of parameter tuning. Furthermore, most state-of-the-art methods incorporate one or more thresholds, and it is difficult to determine accurate threshold settings to obtain desirable performance. These problems arise mostly because the available training data for skin detection are imprecise and incomplete, which leads to uncertainty in classification. This requires a robust fusion framework to combine available information sources with some degree of certainty. This paper addresses these issues by proposing a fusion-based method termed Dempster–Shafer-based Skin Detection (DSSD). This method uses six prominent skin detection criteria as sources of information (SoI), quantifies their reliabilities (confidences), and then combines their confidences based on the Dempster–Shafer Theory (DST) of evidence. We use the DST as it offers a powerful and flexible framework for representing and handling uncertainties in available information and thus helps to overcome the limitations of the current state-of-the-art methods. We have verified this method on a large dataset containing a variety of images, and achieved a 90.17% correct detection rate (CDR). We also demonstrate how DSSD can be used when very little training data are available, achieving a CDR as high as 87.47% while the best result achieved by a Bayesian classifier is only 68.81% on the same dataset. Finally, a generalized DSSD (GDSSD) is proposed achieving 91.12% CDR. 相似文献
103.
In Sun Cho Dong Kyun Yim Chae Hyun Kwak Jae Sul An Hee Suk Roh Kug Sun Hong 《Journal of luminescence》2012,132(2):375-380
BaO–SiO2:Eu2+ phosphors with different Ba/Si mole ratio were prepared using a solid-state reaction method, and their crystal structure dependent-photoluminescence properties were investigated. The prepared phosphor powders were characterized using X-ray diffraction (XRD), field-emission electron microscopy (FE-SEM) and fluorescence spectroscopy. The emission band of the Eu2+ activator varied from orange to blue with varying crystal structure of the host materials, which was related to the crystal field splitting of the Eu 5d orbitals. These emission color changes were examined by calculating the electronic band structure properties such as the density of the state. Moreover, the host material with Ba/Si=1 (BaSiO3) for Eu2+, which exhibited a yellow emission when excited with near UV light, was further characterized for enhancing its emission intensity. 相似文献
104.
Joonkeun Min Priyank N. Shah Chang‐Geun Chae Jae‐Suk Lee 《Macromolecular rapid communications》2012,33(23):2029-2034
Poly(furfuryl isocyanate) (PFIC), which includes the reactive furan group, was synthesized by anionic polymerization using a sodium benzhydroxide (Na‐BH), self‐assembly initiator. We determined the optimum polymerization conditions by varying both the reaction time and the molar ratio of the monomer to the initiator. Block copolymer, poly(furfuryl isocyanate)‐b‐poly(n‐hexyl isocyanate), was synthesized under optimized polymerization conditions. The PFIC was modified by Diels–Alder reactions with C60 for functionalization. Transmission electron microscopy (TEM) was used to study the self‐assembly of block copolymers and modified block copolymer with C60. C60 formed highly ordered aggregates on the PFIC domains via self‐assembly of the block copolymer. 相似文献
105.
This study investigated the determination of Au in rock samples using collision cell quadrupole inductively coupled plasma
mass spectrometry (ICP-MS). It is essential to remove various interferents using a collision cell because polyatomic ions
such as 181Ta16O+ and 180Hf16O1H+ can interfere with the direct determination of monoisotopic 197Au when using ICP-MS. The addition of oxygen as a reaction gas removed isobaric interferents by transforming TaO+ and HfOH+ to TaO2+, TaO3+, and HfO2H+, HfO3H+, respectively, in the cell without significant Au+ loss. The ion kinetic energy effect (IKEE) due to the potential difference between the plasma and the hexapole affected the
reactions in the cell. Au and interfering ions were very sensitive to cell bias voltage (Vc) at constant plasma potential
(Vp) and quadrupole bias voltage (Vq). Under the condition of hot plasma, the transmission of ions was promoted, and the maximum
Au signal intensity was 50% greater than under normal conditions. At Vc > 7 V, TaO+ ions were removed to background level. Optimized conditions for real sample analysis were obtained by introducing He as an
additional collision gas in hot plasma. TaO+ ions were removed to background level at He flow rates above 0.6 mL min−1, and the Au signal remained high. The detection limit (three times the standard deviation of the blank) of this method was
3.06 pg g−1. The results for reference materials (STM-1 and DGPM-1) and spiked samples showed good agreement between specified and measured
concentrations. 相似文献
106.
Sung Won Chae Geon Choi Hee Joon Kang Jong Ouck Choi Sung Min Jin 《Journal of voice》2001,15(2):278-283
We have evaluated the relationship between voice change and premenstrual syndrome (PMS) by comparing acoustic measurements made during the follicular phase and the premenstrual phase. Twenty-eight women were followed for 2 months for this study. Each participant was asked to produce an /a/ sound for 5 seconds at the midfollicular phase of the menstrual cycle and then 2-3 days before menstruation. Each voice sample was stored and analyzed by the Dr. Speech Science program. The voice data collected from all subjects during the two phases were compared. After that, the subjects were divided into a PMS-positive and PMS-negative group according to the criteria cited in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV); the voice data from each group were compared separately between the two phases. There was no significant difference in the acoustic parameters between the two phases in all subjects (N = 28). In the PMS-positive group (N = 16), jitter was significantly increased during the premenstrual phase compared to the follicular phase (p = 0.048). The patient's PMS score was not correlated with the severity of voice change. We conclude that the change of voice parameter was objectively identified in the PMS-positive group, therefore more careful voice habituation is required during the premenstrual phase in that group. 相似文献
107.
Hyperfine Interactions - Ultrafine Ti-doped CoFe2O4 powders, Ti0.2Co1.2Fe1.6O4, are fabricated by the sol gel method and their magnetic and crystallographic properties depending on annealing... 相似文献
108.
Laily Rahmawati Sang Hee Park Dong Seon Kim Hwa Pyoung Lee Nur Aziz Chae Young Lee Seung A Kim Seok Gu Jang Dong Sam Kim Jae Youl Cho 《Molecules (Basel, Switzerland)》2022,27(1)
Prasiola japonica possesses several biological activities. However, reports on the anti-inflammatory activities and molecular mechanisms of its different solvent fractions remain limited. In this study, we investigated the potential anti-inflammatory activities of P. japonica ethanol extract (Pj-EE) and four solvent fractions of Pj-EE made with hexane (Pj-EE-HF), chloroform (Pj-EE-CF), butanol (Pj-EE-BF), or water (Pj-EE-WF) in both in vitro (LPS-induced macrophage-like RAW264.7 cells) and in vivo (carrageenan-induced acute paw edema mouse models) experiments. The most active solvent fraction was selected for further analysis. Various in vitro and in vivo assessments, including nitric oxide (NO), cytokines, luciferase assays, real-time polymerase chain reactions, and immunoblotting analyses were performed to evaluate the underlying mechanisms. In addition, the phytochemical constituents were characterized by Liquid chromatography-tandem mass spectrometry. In in vitro studies, the highest inhibition of NO production was observed in Pj-EE-CF. Further examination revealed that Pj-EE-CF decreased the expression of inflammation-related cytokines in LPS-induced RAW264.7 cells and suppressed subsequent AP-1-luciferase activity by inhibition of phosphorylation events in the AP-1 signaling pathway. Pj-EE-CF treatment also demonstrated the strongest reduction in thickness and volume of carrageenan-induced paw edema, while Pj-EE-BF showed the lowest activity. Furthermore, Pj-EE-CF also reduced gene expression and cytokines production in tissue lysates of carrageenan-induced paw edema. These findings support and validate the evidence that Pj-EE, and especially Pj-EE-CF, could be a good natural source for an anti-inflammatory agent that targets the AP1 pathway. 相似文献
109.
S. I. Yun Ki-Dong Oh Kwon-Sang Ryu Chang-Geon Kim H. L. Park H. J. Seo Chae Kum 《Applied physics. B, Lasers and optics》1986,40(2):95-98
We have used a modified photothermal probe beam deflection system with a back pumping configuration for the measurements of the temperature-dependent thermal diffusivity of atmospheric air. The results are consistent and reasonably well agree with the literature values. The measured thermal diffusivity values are the same for the same measuring temperature regardless of the beam offsets and the deflecting surface temperatures. For the gas with known temperature-dependent thermal diffusivity, this method can be used to deduce the temperature of a gas from the measured thermal diffusivity value. 相似文献
110.
We report a flexible all-optical gain controlled bidirectional optical amplifier. The device achieves constant gain and low noise figure over a large input power range. Moreover, the device removes Rayleigh backscattered light and amplifier noise. 相似文献