796 research outputs found

    Vacancy-driven Na Superionic Conduction in New Ca-doped Na3PS4 for All-Solid-State Na-ion Batteries

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    Department of Energy Engineering (Battery Science and Technology)As the applications of lithium-ion batteries (LIBs) are expanding from mobile electronic devices to electrical vehicles (EVs) and energy storage systems (ESSs), concerns about their safety hazard also increased. The safety issues for LIBs are originated from flammable organic liquid electrolytes. In this regard, all-solid-state lithium-ion batteries (ASLBs) employing nonflammable inorganic solid electrolytes (SEs) have emerged as a promising alternative. In another aspect, as the price of Li sources soared, Na-ion batteries (NIBs) are considered to be promising next-generation batteries especially for ESS application. Due to similarities of NIBs to LIBs in terms of chemistry/electrochemistry, extensive research efforts have been focused on NIBs in recent years. Furthermore, development of Na-ion conducting SEs opened a research field for all-solid-state Na-ion batteries (ASNBs). Herein, the highly conductive Ca-doped Na3PS4 SEs and their use for bulk-type ASNBs will be presented in this thesis.ope

    An exciplex-based light-emission pathway for solution-state electrochemiluminescent devices

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    This work was financially supported by the Alexander von Humboldt Foundation (Humboldt-Professorship to M.C.G.). C.K.M. acknowledges funding from the European Commission through a Marie Skłodowska Curie individual fellowship (101029807). J.F.B. acknowledges funding from Beverly and Frank MacInnis via the University of St Andrews.Electrochemiluminescence (ECL) allows the design of unique light-emitting devices that use organic semiconductors in a liquid or gel state, which allows for simpler and more sustainable device fabrication and facilitates unconventional device form-factors. Compared to solid-state organic LEDs, ECL devices (ECLDs) have attracted less attention due to their currently much lower performance. ECLD operation is typically based on an annihilation pathway that involves electron transfer between reduced and oxidized luminophore species; the intermediate radical ions produced during annihilation dramatically reduce device stability. Here, the effects of radical ions are mitigated by an exciplex formation pathway and a remarkable improvement in luminance, luminous efficacy, and operational lifetime is demonstrated. Electron donor and acceptor molecules are dissolved at high concentrations and recombined as an exciplex upon their oxidization/reduction. The exciplex then transfers its energy to a nearby dye, allowing the dye to emit light without undergoing oxidation/reduction. Furthermore, the application of a mesoporous TiO2 electrode increases the contact area and hence the number of molecules participating in ECL , thereby obtaining devices with a very high luminance of 3790 cd m−2 and a 30-fold improved operational lifetime. This study paves the way for the development of ECLDs into highly versatile light sources.Publisher PDFPeer reviewe

    Pixel data real time processing as a next step for HL-LHC upgrades and beyond

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    The experiments at LHC are implementing novel and challenging detector upgrades for the High Luminosity LHC, among which the tracking systems. This paper reports on performance studies, illustrated by an electron trigger, using a simplified pixel tracker. To achieve a real-time trigger (e.g. processing HL-LHC collision events at 40 MHz), simple algorithms are developed for reconstructing pixel-based tracks and track isolation, utilizing look-up tables based on pixel detector information. Significant gains in electron trigger performance are seen when pixel detector information is included. In particular, a rate reduction up to a factor of 20 is obtained with a signal selection efficiency of more than 95\% over the whole η\eta coverage of this detector. Furthermore, it reconstructs p-p collision points in the beam axis (z) direction, with a high precision of 20 μ\mum resolution in the very central region (η<0.8|\eta| < 0.8), and, up to 380 μ\mum in the forward region (2.7 <η<< |\eta| < 3.0). This study as well as the results can easily be adapted to the muon case and to the different tracking systems at LHC and other machines beyond the HL-LHC. The feasibility of such a real-time processing of the pixel information is mainly constrained by the Level-1 trigger latency of the experiment. How this might be overcome by the Front-End ASIC design, new processors and embedded Artificial Intelligence algorithms is briefly tackled as well.Comment: To be submitted to JHE

    Protective Effectiveness of Hantavirus Vaccine

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    A case-control study in the Republic of Korea evaluated the protective effectiveness of the hantavirus vaccine. Point estimates showed increasing effectiveness with increasing numbers of doses received: 25% for one dose, 46% for two doses, and 75% for three doses. All 95% confidence intervals overlapped zero; therefore, the findings could be due to chance

    High-density integration of ultrabright OLEDs on a miniaturized needle-shaped CMOS backplane

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    This work was supported in part by the Defense Advanced Research Projects Agency (DARPA) under Contract N6600117C4012, by the National Institutes of Health under Grant U01NS090596, and by the Leverhulme Trust (RPG-2017-231). C.K.M. acknowledges funding from the European Commission through a Marie Skłodowska Curie individual fellowship (101029807). M.C.G. acknowledges funding from the Alexander von Humboldt Stiftung (Humboldt-Professorship). We thank Aaron Naden for the FIB/STEM measurements (Engineering and Physical Sciences Research Council under grant numbers EP/L017008/1, EP/R023751/1 and EP/T019298/1).Direct deposition of organic light-emitting diodes (OLEDs) on silicon-based complementary metal–oxide–semiconductor (CMOS) chips has enabled self-emissive microdisplays with high resolution and fill-factor. Emerging applications of OLEDs in augmented and virtual reality (AR/VR) displays and in biomedical applications, e.g., as brain implants for cell-specific light delivery in optogenetics, require light intensities orders of magnitude above those found in traditional displays. Further requirements often include a microscopic device footprint, a specific shape and ultrastable passivation, e.g., to ensure biocompatibility and minimal invasiveness of OLED-based implants. In this work, up to 1024 ultrabright, microscopic OLEDs are deposited directly on needle-shaped CMOS chips. Transmission electron microscopy and energy-dispersive X-ray spectroscopy are performed on the foundry-provided aluminum contact pads of the CMOS chips to guide a systematic optimization of the contacts. Plasma treatment and implementation of silver interlayers lead to ohmic contact conditions and thus facilitate direct vacuum deposition of orange- and blue-emitting OLED stacks leading to micrometer-sized pixels on the chips. The electronics in each needle allow each pixel to switch individually. The OLED pixels generate a mean optical power density of 0.25 mW mm−2, corresponding to >40 000 cd m−2, well above the requirement for daylight AR applications and optogenetic single-unit activation in the brain.Publisher PDFPeer reviewe

    A Pulmonary Paragonimiasis Case Mimicking Metastatic Pulmonary Tumor

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    Pulmonary paragonimiasis is a relatively rare cause of lung disease revealing a wide variety of radiologic findings, such as air-space consolidation, nodules, and cysts. We describe here a case of pulmonary paragonimiasis in a 27-year-old woman who presented with a 2-month history of cough and sputum. Based on chest computed tomography (CT) scans and fluorodeoxyglucose positron emission tomography (FDG-PET) findings, the patient was suspected to have a metastatic lung tumor. However, she was diagnosed as having Paragonimus westermani infection by an immunoserological examination using ELISA. Follow-up chest X-ray and CT scans after chemotherapy with praziquantel showed an obvious improvement. There have been several reported cases of pulmonary paragonimiasis mimicking lung tumors on FDG-PET. However, all of them were suspected as primary lung tumors. To our knowledge, this patient represents the first case of paragonimiasis mimicking metastatic lung disease on FDG-PET CT imaging

    Carcinosarcoma of the Maxillary Sinus

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    Carcinosarcoma is a highly malignant tumor characterized by dual malignant histologic differentiation of epithelial and mesenchymal components. The tumor is extremely rare in the sinonasal tract. We report a case of a 62-year-old man with carcinosarcoma involving the maxillary sinus
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