266 research outputs found

    Uncertainty Analysis of Calibration Standards for On-wafer Measurements over 110 GHz

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    We present uncertainty analysis of calibration standards on a commercial calibration substrate for on-wafer S-parameter measurements over 110 GHz. At these frequencies, manufacturing tolerance is comparable to the sizes of calibration standards. Thus accurate knowledge about the actual dimensions of calibration standards becomes critical for system calibration and establishment of uncertainty budget. In this work, three different tools namely surfaceprofiler, optical interferometer, and Scanning Electron Microscope (SEM) have been used to measure calibration standards and investigate the effect of manufacturing tolerance on electrical parameters by using numerical software. Finally uncertainty of calibration standards will be given. In this work, we use three different techniques to characterise calibration standards and obtain manufacturing tolerance. And then numerical software is used to simulate how the electrical parameters are affected by the manufacturing imperfections. Finally uncertainty of the calibration is analysed

    Two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

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    The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388

    Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV

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    Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at sNN\sqrt{s_{_{\rm NN}}} = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in η<0.8|\eta|<0.8 and 0.3<pT<200.3 < p_T < 20 GeV/cc are compared to the expectation in pp collisions at the same sNN\sqrt{s_{\rm NN}}, scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAAR_{\rm AA}. The result indicates only weak medium effects (RAAR_{\rm AA} \approx 0.7) in peripheral collisions. In central collisions, RAAR_{\rm AA} reaches a minimum of about 0.14 at pT=6p_{\rm T}=6-7GeV/cc and increases significantly at larger pTp_{\rm T}. The measured suppression of high-pTp_{\rm T} particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98

    Recent Progress in Electrospun Nanofibres: Reinforcement Effect and Mechanical Performance

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    Composite materials are becoming increasingly important as structural materials for aeronautical and space engineering, naval, automotive, and civil engineering, sporting goods, and other consumer products. Fiber-based reinforcement represents one of the most effective manufacturing strategies for enhancing the mechanical strength and other properties of composite materials. Electrospinning has gained widespread interest in the last two decades because of its ability to fabricate continuous ultrafine nanofibers with unique characteristics. The impact of electrospinning on fiber synthesis and processing, characterization, and applications in drug delivery, nanofiltration, tissue scaffolding, and electronics has been extensively studied in the past. In this article, the authors have focused on a comprehensive review of the mechanical performance and properties of electrospun nanofibers as potential reinforcements as well as their advanced nanocomposites

    Study of e+eppˉe^+e^- \rightarrow p\bar{p} in the vicinity of ψ(3770)\psi(3770)

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    Using 2917 pb1\rm{pb}^{-1} of data accumulated at 3.773~GeV\rm{GeV}, 44.5~pb1\rm{pb}^{-1} of data accumulated at 3.65~GeV\rm{GeV} and data accumulated during a ψ(3770)\psi(3770) line-shape scan with the BESIII detector, the reaction e+eppˉe^+e^-\rightarrow p\bar{p} is studied considering a possible interference between resonant and continuum amplitudes. The cross section of e+eψ(3770)ppˉe^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}, σ(e+eψ(3770)ppˉ)\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}), is found to have two solutions, determined to be (0.059±0.032±0.0120.059\pm0.032\pm0.012) pb with the phase angle ϕ=(255.8±37.9±4.8)\phi = (255.8\pm37.9\pm4.8)^\circ (<<0.11 pb at the 90% confidence level), or σ(e+eψ(3770)ppˉ)=(2.57±0.12±0.12\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}) = (2.57\pm0.12\pm0.12) pb with ϕ=(266.9±6.1±0.9)\phi = (266.9\pm6.1\pm0.9)^\circ both of which agree with a destructive interference. Using the obtained cross section of ψ(3770)ppˉ\psi(3770)\rightarrow p\bar{p}, the cross section of ppˉψ(3770)p\bar{p}\rightarrow \psi(3770), which is useful information for the future PANDA experiment, is estimated to be either (9.8±5.79.8\pm5.7) nb (<17.2<17.2 nb at 90% C.L.) or (425.6±42.9)(425.6\pm42.9) nb

    An overview of progress in electrolytes for secondary zinc-air batteries and other storage systems based on zinc

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    The revived interest and research on the development of novel energy storage systems with exceptional inherent safety, environmentally benign and low cost for integration in large scale electricity grid and electric vehicles is now driven by the global energy policies. Within various technical challenges yet to be resolved and despite extensive studies, the low cycle life of the zinc anode is still hindering the implementation of rechargeable zinc batteries at industrial scale. This review presents an extensive overview of electrolytes for rechargeable zinc batteries in relation to the anode issues which are closely affected by the electrolyte nature. Widely studied aqueous electrolytes, from alkaline to acidic pH, as well as non-aqueous systems including polymeric and room temperature ionic liquids are reported. References from early rechargeable Zn-air research to recent results on novel Zn hybrid systems have been analyzed. The ambition is to identify the challenges of the electrolyte system and to compile the proposed improvements and solutions. Ultimately, all the technologies based on zinc, including the more recently proposed novel zinc hybrid batteries combining the strong points of lithium-ion, redox-flow and metal-air systems, can benefit from this compilation in order to improve secondary zinc based batteries performance.Basque Country University (ZABALDUZ2012 program), and the Basque Country Government (Project: CIC energiGUNÉ16 of the ELKARTEK program) and the European Commission through the project ZAS: “Zinc Air Secondary innovative nanotech based batteries for efficient energy storage” (Grant Agreement 646186
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