71 research outputs found

    Fully Printed Ultraflexible Supercapacitor Supported by a Single-Textile Substrate

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    Textile-based supercapacitors have recently attracted much attention owing to their great potential as energy storage components in wearable electronics. However, fabrication of a high-performance, fully printed, and ultraflexible supercapacitor based on a single textile still remains a great challenge. Herein, a facile, low-cost, and textile-compatible method involving screen printing and transfer printing is developed to construct all-solid-state supercapacitors on a single silk fabric. The system exhibits a high specific capacitance of 19.23 mF cm<sup>–2</sup> at a current density of 1 mA cm<sup>–2</sup> and excellent cycling stability with capacitance retention of 84% after 2000 charging/discharging cycles. In addition, the device possesses superior mechanical stability with stable performance and structures after 100 times of bending and twisting. A butterfly-patterned supercapacitor was manufactured to demonstrate the compatibility of the printing approaches to textile aesthetics. This work may provide a facile and versatile approach for fabricating rationally designed ultraflexible textile-based power-storage elements for potential applications in smart textiles and stretchable/flexible electronics

    Insights into the Unexpected Chemoselectivity for the N‑Heterocyclic Carbene-Catalyzed Annulation Reaction of Allenals with Chalcones

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    Lewis base N-heterocyclic carbene (NHC)-catalyzed annulation is the subject of extensive interest in synthetic chemistry, but the reaction mechanisms, especially the unexpected chemoselectivity of some of these reactions, are poorly understood. In this work, a systematic theoretical calculation has been performed on NHC-catalyzed annulation between allenals and chalcone. Multiple possible reaction pathways (A–E) leading to three different products have been characterized. The calculated results reveal that NHC is more likely to initiate the reaction by nucleophilic attack on the center carbon atom of the allene group but not the carbonyl carbon atom in allenals leading to the Breslow intermediate, which is remarkably different from the other NHC-catalyzed annulations of unsaturated aldehydes with chalcones. The computed energy profiles demonstrate that the most energetically favorable pathway (A) results in polysubstituted pyranyl aldehydes, which reasonably explains the observed chemoselectivity in the experiment. The observed chemoselectivity is demonstrated to be thermodynamically but not kinetically controlled, and the stability of the Breslow intermediate is the key for the possibility of homoenolate pathway D and enolate pathway E. This work can improve our understanding of the multiple competing pathways for NHC-catalyzed annulation reactions of unsaturated aldehydes with chalcones and provide valuable insights for predicting the chemoselectivity for this kind of reaction

    Adaptive Path Selection for Link Loss Inference in Network Tomography Applications

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    <div><p>In this study, we address the problem of selecting the optimal end-to-end paths for link loss inference in order to improve the performance of network tomography applications, which infer the link loss rates from the path loss rates. Measuring the path loss rates using end-to-end probing packets may incur additional traffic overheads for networks, so it is important to select the minimum path set carefully while maximizing their performance. The usual approach is to select the maximum independent paths from the candidates simultaneously, while the other paths can be replaced by linear combinations of them. However, this approach ignores the fact that many paths always exist that do not lose any packets, and thus it is easy to determine that all of the links of these paths also have 0 loss rates. Not considering these <i>good</i> paths will inevitably lead to inefficiency and high probing costs. Thus, we propose an adaptive path selection method that selects paths sequentially based on the loss rates of previously selected paths. We also propose a theorem as well as a graph construction and decomposition approach to efficiently find the most valuable path during each round of selection. Our new method significantly outperforms the classical path selection method based on simulations in terms of the probing cost, number of accurate links determined, and the running speed.</p></div

    Computational insights into the origin of decrease/increase in potency of <i>N</i>-CDPCB analogues toward FTO

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    Computational insights into the origin of decrease/increase in potency of <i>N</i>-CDPCB analogues toward FT

    Set of Paths in Fig 1.

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    <p>Set of Paths in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163706#pone.0163706.g001" target="_blank">Fig 1</a>.</p

    Number of Links that could be Determined Accurately in the Three Scenarios.

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    <p>(a)AS1239 in model 1(b)AS1239 in model 2(c)AS1239 in model 3(d)AS1755 in model 1(e)AS1755 in model 2(f)AS1755 in model 3(g)AS3356 in model 1(h)AS3356 in model 2(i)AS3356 in model 3(j)AS6461 in model 1(k)AS6461 in model 2(l)AS6461 in model 3(m)Legend.</p
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