427 research outputs found

    Fuzzy Clustering Image Segmentation Based on Particle Swarm Optimization

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    Image segmentation refers to the technology to segment the image into different regions with different characteristics and to extract useful objectives, and it is a key step from image processing to image analysis. Based on the comprehensive study of image segmentation technology, this paper analyzes the advantages and disadvantages of the existing fuzzy clustering algorithms; integrates the particle swarm optimization (PSO) with the characteristics of global optimization and rapid convergence and fuzzy clustering (FC) algorithm with fuzzy clustering effects starting from the perspective of particle swarm and fuzzy membership restrictions and gets a PSO-FC image segmentation algorithm so as to effectively avoid being trapped into the local optimum and improve the stability and reliability of clustering algorithm. The experimental results show that this new PSO-FC algorithm has excellent image segmentation effects

    ‘Wh-on-earth’ in Chinese speakers’ L2 English: Evidence of dormant features

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    Adopting a decompositional approach to items in the lexicon, this article reports on an empirical study investigating Chinese speakers’ second language (L2) acquisition of English wh-on-earth questions (i.e. questions with phrases like what on earth or who on earth). An acceptability judgment task, a discourse-completion task and an interpretation task were used in the study, and the results indicate that in Chinese speakers’ L2 English, the form of wh-on-earth can be learned and stored in a native-like manner, but without being endowed with fully elaborated features. A distinction between active features and dormant features in L2 lexicon is made in the analysis, and it is argued that features transferred from learners’ L1 to their L2 are likely to lose their vigour and vitality in their L2 lexicon and become dormant if there is no evidence in the target language input to confirm or disconfirm them. A typical consequence of a dormant feature is random behaviours of a related structure in L2 learners’ production and interpretation. The results of the study show that semantic features, discourse features as well as morphosyntactic features can become dormant in L2 lexicon. I acknowledge the assistance that the National Research Centre for Foreign Language Education of Beijing Foreign Studies University gave to me as its Overseas Research Fellow.This is the accepted manuscript. The final version is available from Sage at http://slr.sagepub.com/content/30/4/515

    Search for heavy resonance decaying into a photon and a Higgs bosonwith the ATLAS detector at the LHC

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    A search for heavy resonance decaying into a photon and a Higgs boson is performed, where the Higgs boson continually decaying into a pair of b-quarks. Data was collected from 2015 to 2018 using the ATLAS detector at the LHC at the center-of-mass energy of √s= 13 TeV with an integrated luminosity of 139 fb−1. To improve the sensitivity of this analysis, a novel H→bb tagger method, Center-of-Mass sub-jet b-tagging algorithm, is implemented to identify the two b-quarks in a single Large-R jet. There is no obvious deviation from the Standard Model prediction. Upper limit is set usingCLsstrategy at 95% confidence level. Compared with previous ATLAS and CMSresult, on top of the statistic gain, more than 30% improvement is observed in the expected upper limit

    Beneficial influence of nanocarbon on the aryliminopyridylnickel chloride catalyzed ethylene polymerization

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    A series of 1-aryliminoethylpyridine ligands (L1―L3) was synthesized by condensation of 2-acetylpyridine with 1-aminonaphthalene, 2-aminoanthracene or 1-aminopyrene, respectively. Reaction with nickel dichloride afforded the corresponding nickel (II) chloride complexes (Ni1–Ni3). All compounds were fully characterized and the molecular structures of Ni1 and Ni3 are reported. Upon activation with methylaluminoxane (MAO), all nickel complexes exhibit high activities for ethylene polymerization, producing waxes of low molecular weight and narrow polydispersity. The presence of multi-walled carbon nanotubes (MWCNTs) or few layer graphene (FLG) in the catalytic medium can lead to an increase of productivity associated to a modification of the polymer structure

    Fast Fault Protection Based on Direction of Fault Current for the High-Surety Power-Supply System

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    Roles of circulating soluble interleukin (IL)-6 receptor and IL-6 receptor expression on CD4+ T cells in patients with chronic hepatitis B

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    SummaryObjectivesThe objective of this study was to investigate the potential clinical roles of circulating soluble interleukin (IL)-6 receptor (sIL-6R) and IL-6R expression on CD4+ T cells (CD4+ IL-6R+ T cells) in chronic hepatitis B (CHB) patients.MethodsOne hundred and thirty-three subjects, including 72 CHB patients, 27 asymptomatic carriers, eight acute hepatitis B (AHB) patients, and 26 healthy donors were included in this study. Plasma IL-6 and sIL-6R levels were measured by enzyme-linked immunosorbent assay (ELISA); the frequency of CD4+ IL-6R+ T cells was detected by flow cytometry analysis.ResultsOur data showed a significant increase in plasma sIL-6R levels and the frequency of CD4+ IL-6R+ T cells in peripheral blood in CHB patients compared to asymptomatic carriers and healthy controls (both p<0.05). The elevated prevalence of CD4+ IL-6R+ T cells was positively associated with increased serum alanine aminotransferase levels in CHB patients (r = 0.316, p = 0.007), but was not correlated with serum hepatitis B virus (HBV) DNA load. Moreover, CHB patients with an HBV DNA load >1.0×106 copies/ml had a lower level of plasma sIL-6R than those with an HBV DNA load <1.0×106 copies/ml.ConclusionsCirculating sIL-6R and CD4+ IL-6R+ T cells were increased in CHB patients. Elevated plasma sIL-6R is probably associated with HBV elimination, and CD4+ IL-6R+ T cells in peripheral blood might contribute to the pathogenesis of liver injury in CHB patients

    Metallothioneins Are Required for Formation of Cross-Adaptation Response to Neurobehavioral Toxicity from Lead and Mercury Exposure in Nematodes

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    Metallothioneins (MTs) are small, cysteine-rich polypeptides, but the role of MTs in inducing the formation of adaptive response is still largely unknown. We investigated the roles of metallothionein genes (mtl-1 and mtl-2) in the formation of cross-adaptation response to neurobehavioral toxicity from metal exposure in Caenorhabditis elegans. Pre-treatment with mild heat-shock at L2-larva stage effectively prevented the formation of the neurobehavioral defects and the activation of severe stress response in metal exposed nematodes at concentrations of 50 and 100 µM, but pre-treatment with mild heat-shock did not prevent the formation of neurobehavioral defects in 200 µM of metal exposed nematodes. During the formation of cross-adaptation response, the induction of mtl-1 and mtl-2 promoter activity and subsequent GFP gene expression were sharply increased in 50 µM or 100 µM of metal exposed Pmtl-1::GFP and Pmtl-2::GFP transgenic adult animals after mild heat-shock treatment compared with those treated with mild heat-shock or metal exposure alone. Moreover, after pre-treatment with mild heat-shock, no noticeable increase of locomotion behaviors could be observed in metal exposed mtl-1 or mtl-2 mutant nematodes compared to those without mild heat-shock pre-treatment. The defects of adaptive response to neurobehavioral toxicity induced by metal exposure formed in mtl-1 and mtl-2 mutants could be completely rescued by the expression of mtl-1 and mtl-2 with the aid of their native promoters. Furthermore, over-expression of MTL-1 and MTL-2 at the L2-larval stage significantly suppressed the toxicity on locomotion behaviors from metal exposure at all examined concentrations. Therefore, the normal formation of cross-adaptation response to neurobehavioral toxicity induced by metal exposure may need the enough accumulation of MTs protein in animal tissues

    Focal shift of silicon microlens array in mid-infrared regime

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    采用严格数值算法对中红外硅微透镜阵列进行了模拟,该微透镜阵列特征尺寸小于波长工作波长.研究发现该微透镜阵列存在一个显著的离焦效应,其离焦量达到0; .4左右,超出了现有的传统理论模型预测范围.对微透镜阵列进行了制作和焦距测试,发现测试结果跟数值模拟基本吻合.微纳衍射光学集成系统中透镜离焦量是; 系统集成非常重要的一个参数,该研究结果为硅微透镜阵列和中红外探测器光学集成提供有效参考.In this study rigorous numerical model was utilized to characterize the focal shift of the diffractive mid infrared (MIR) silicon microlens arrays (MLAs) with the critical size smaller than the working wavelength. We found a more pronounced focal shift in mid-infrared wavelength which is out of the range predicted by existing models. Focal properties of the MLAs were also measured experimentally. The results agrees well with the simulation results. Our results provide a reference point in understanding the focal shift in MIR regime, which is important in terms of deciding the focal length of micro-nano lens systems, especially when dealing with the integration of diffractive devices in infrared optical system.Special Project on the Integration of Industry, Education and Research; of Aviation Industry Corporation of China [CXY2011XD24

    Acoustic calculation in low frequency sonopheresis based on bubble dynamics

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    As a type of transdermal permeability enhancement, low frequency sonophoresis (LFS) has been studied for more than twenty years. The acoustic pressure in LFS is a crucial ultrasonic parameter to improve the permeability, but it is difficult to measure in the drug donor because of its small size and narrow shape. In this paper, an acoustic-piezoelectric coupling model is established based on bubble dynamics, which can be utilized to calculate the acoustic pressure distributions in LFS using a commercial finite element software called COMSOL multiphysics. The calculated results of acoustic pressure are in accordance with the measured values, so this model has great potential for theoretical analyses in acoustic fields of LFS. Calculated and experimental results show that the maximum acoustic pressure is under the transducer’s head, and the value dropped as away from the head due to the acoustic attenuation caused by cavitation; the transducer head should be closer to the skin to obtain larger acoustic pressure on the skin. Therefore, this model can be used to simulate and analyze the characteristics of acoustic fields, as a theoretical tool for the structural design of the ultrasonic transducer applied in LFS
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