P2P (Port to Port) 디지털 물류 플랫폼 설계

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Reduction of Compression Artifacts Using a Densely Cascading Image Restoration Network

Since high quality realistic media are widely used in various computer vision applications, image compression is one of the essential technologies to enable real-time applications. Image compression generally causes undesired compression artifacts, such as blocking artifacts and ringing effects. In this study, we propose a densely cascading image restoration network (DCRN), which consists of an input layer, a densely cascading feature extractor, a channel attention block, and an output layer. The densely cascading feature extractor has three densely cascading (DC) blocks, and each DC block contains two convolutional layers, five dense layers, and a bottleneck layer. To optimize the proposed network architectures, we investigated the trade-off between quality enhancement and network complexity. Experimental results revealed that the proposed DCRN can achieve a better peak signal-to-noise ratio and structural similarity index measure for compressed joint photographic experts group (JPEG) images compared to the previous methods

Multiscale Engineered Si/SiO x Nanocomposite Electrodes for Lithium-Ion Batteries Using Layer-by-Layer Spray Deposition

Si-based high-capacity materials have gained much attention as an alternative to graphite in Li-ion battery anodes. Although Si additions to graphite anodes are now commercialized, the fraction of Si that can be usefully exploited is restricted due to its poor cyclability arising from the large volume changes during charge/discharge. Si/SiO x nanocomposites have also shown promising behavior, such as better capacity retention than Si alone because the amorphous SiO x helps to accommodate the volume changes of the Si. Here, we demonstrate a new electrode architecture for further advancing the performance of Si/SiO x nanocomposite anodes using a scalable layer-by-layer atomization spray deposition technique. We show that particulate C interlayers between the current collector and the Si/SiO x layer and between the separator and the Si/SiO x layer improved electrical contact and reduced irreversible pulverization of the Si/SiO x significantly. Overall, the multiscale approach based on microstructuring at the electrode level combined with nanoengineering at the material level improved the capacity, rate capability, and cycling stability compared to that of an anode comprising a random mixture of the same materials

Si Nanocrystal-Embedded SiOxnanofoils: Two-Dimensional Nanotechnology-Enabled High Performance Li Storage Materials

Silicon (Si) based materials are highly desirable to replace currently used graphite anode for lithium ion batteries. Nevertheless, its usage is still a big challenge due to poor battery performance and scale-up issue. In addition, two-dimensional (2D) architectures, which remain unresolved so far, would give them more interesting and unexpected properties. Herein, we report a facile, cost-effective, and scalable approach to synthesize Si nanocrystals embedded 2D SiO x nanofoils for next-generation lithium ion batteries through a solution-evaporation-induced interfacial sol-gel reaction of hydrogen silsesquioxane (HSiO 1.5 , HSQ). The unique nature of the thus-prepared centimeter scale 2D nanofoil with a large surface area enables ultrafast Li + insertion and extraction, with a reversible capacity of more than 650 mAh g -1 , even at a high current density of 50 C (50 A g -1 ). Moreover, the 2D nanostructured Si/SiO x nanofoils show excellent cycling performance up to 200 cycles and maintain their initial dimensional stability. This superior performance stems from the peculiar nanoarchitecture of 2D Si/SiO x nanofoils, which provides short diffusion paths for lithium ions and abundant free space to effectively accommodate the huge volume changes of Si during cycling

Two-dimensional SiOx as a high performance Li storage material prepared by solution evaporation induced interfacial sol-gel reaction

Si based anode materials for lithium-ion batteries have gained much attention due to its high theoretical capacity (3,580 mAhg-1). However, Si anode materials have critical limit for their commercial use because of their poor cycle performance associated with severe volume changes during cycling. In this work, we synthesized a two-dimensional(2D) SiOx material by solution evaporation induced interfacial sol-gel reaction. This synthesis method is simple, cost-effective and scalable. The resulting 2D SiOx material showed stable cycle performance with reversible capacity of about 650 mAhg-1 even at a high current density of 50 C (50 A g-1). More detailed analysis of two-dimensional SiOx materials will be discussed in this presentation

Dual-Size Silicon Nanocrystal-Embedded SiO_<i>x</i> Nanocomposite as a High-Capacity Lithium Storage Material

SiO_<i>x</i>-based materials attracted a great deal of attention as high-capacity Li⁺ storage materials for lithium-ion batteries due to their high reversible capacity and good cycle performance. However, these materials still suffer from low initial Coulombic efficiency as well as high production cost, which are associated with the complicated synthesis process. Here, we propose a dual-size Si nanocrystal-embedded SiO_<i>x</i> nanocomposite as a high-capacity Li⁺ storage material prepared <i>via</i> cost-effective sol–gel reaction of triethoxysilane with commercially available Si nanoparticles. In the proposed nanocomposite, dual-size Si nanocrystals are incorporated into the amorphous SiO_<i>x</i> matrix, providing a high capacity (1914 mAh g^–1) with a notably improved initial efficiency (73.6%) and stable cycle performance over 100 cycles. The highly robust electrochemical and mechanical properties of the dual-size Si nanocrystal-embedded SiO_<i>x</i> nanocomposite presented here are mainly attributed to its peculiar nanoarchitecture. This study represents one of the most promising routes for advancing SiO_<i>x</i>-based Li⁺ storage materials for practical use

In Operando Monitoring of the Pore Dynamics in Ordered Mesoporous Electrode Materials by Small Angle X-ray Scattering

To monitor dynamic volume changes of electrode materials during electrochemical lithium storage and removal process is of utmost importance for developing high performance lithium storage materials. We herein report an in operando probing of mesoscopic structural changes in ordered mesoporous electrode materials during cycling with synchrotron-based small angel X-ray scattering (SAXS) technique. In operando SAXS studies combined with electrochemical and other physical characterizations straightforwardly show how porous electrode materials underwent volume changes during the whole process of charge and discharge, with respect to their own reaction mechanism with lithium. This comprehensive information on the pore dynamics as well as volume changes of the electrode materials will not only be critical in further understanding of lithium ion storage reaction mechanism of materials, but also enable the innovative design of high performance nanostructured materials for next generation batteriesclose0

Highly cyclable lithium-sulfur batteries with a dual-type sulfur cathode and a lithiated Si/SiOx nanosphere anode

Lithium−sulfur batteries could become an excellent alternative to replace the currently used lithium-ion batteries due to their higher energy density and lower production cost; however, commercialization of lithium−sulfur batteries has so far been limited due to the cyclability problems associated with both the sulfur cathode and the lithium−metal anode. Herein, we demonstrate a highly reliable lithium−sulfur battery showing cycle performance comparable to that of lithium-ion batteries; our design uses a highly reversible dual type sulfur cathode (solid sulfur electrode and polysulfide catholyte) and a lithiated Si/SiOx nanosphere anode. Our lithium−sulfur cell shows superior battery performance in terms of high specific capacity, excellent charge−discharge efficiency, and remarkable cycle life, delivering a specific capacity of ∼750 mAh g−1 over 500 cycles (85% of the initial capacity). These promising behaviors may arise from a synergistic effect of the enhanced electrochemical performance of the newly designed anode and the optimized layout of the cathode

High-Performance Si/SiO_<i>x</i> Nanosphere Anode Material by Multipurpose Interfacial Engineering with Black TiO_2–<i>x</i>

Silicon oxides (SiO_<i>x</i>) have attracted recent attention for their great potential as promising anode materials for lithium ion batteries as a result of their high energy density and excellent cycle performance. Despite these advantages, the commercial use of these materials is still impeded by low initial Coulombic efficiency and high production cost associated with a complicated synthesis process. Here, we demonstrate that Si/SiO_<i>x</i> nanosphere anode materials show much improved performance enabled by electroconductive black TiO_2–<i>x</i> coating in terms of reversible capacity, Coulombic efficiency, and thermal reliability. The resulting anode material exhibits a high reversible capacity of 1200 mAh g^–1 with an excellent cycle performance of up to 100 cycles. The introduction of a TiO_2–<i>x</i> layer induces further reduction of the Si species in the SiO_<i>x</i> matrix phase, thereby increasing the reversible capacity and initial Coulombic efficiency. Besides the improved electrochemical performance, the TiO_2–<i>x</i> coating layer plays a key role in improving the thermal reliability of the Si/SiO_<i>x</i> nanosphere anode material at the same time. We believe that this multipurpose interfacial engineering approach provides another route toward high-performance Si-based anode materials on a commercial scale