University of Electronic Science and Technology of China

About: University of Electronic Science and Technology of China is a education organization based out in Chengdu, China. It is known for research contribution in the topics: Antenna (radio) & Dielectric. The organization has 50594 authors who have published 58502 publications receiving 711188 citations. The organization is also known as: UESTC.

Two-dimensional copper nanosheets for electrochemical reduction of carbon monoxide to acetate

Abstract: Upgrading carbon dioxide to high-value multicarbon (C2+) products is one promising avenue for fuel and chemical production. Among all the monometallic catalysts, copper has attracted much attention because of its unique ability to convert CO2 or CO into C2+ products with an appreciable selectivity. Although numerous attempts have been made to synthesize Cu materials that expose the desired facets, it still remains a challenge to obtain high-quality nanostructured Cu catalysts for the electroreduction of CO2/CO. Here we report a facile synthesis of freestanding triangular-shaped two-dimensional Cu nanosheets that selectively expose the (111) surface. In a 2 M KOH electrolyte, the Cu nanosheets exhibit an acetate Faradaic efficiency of 48% with an acetate partial current density up to 131 mA cm−2 in electrochemical CO reduction. Further analysis suggest that the high acetate selectivity is attributed to the suppression of ethylene and ethanol formation, probably due to the reduction of exposed (100) and (110) surfaces. Upgrading CO to high-value multicarbon products is a promising avenue for fuel and chemical feedstock production. Here triangular Cu nanosheets that selectively expose the (111) surface exhibit a high acetate partial current density (131 mA cm–2) and Faradaic efficiency (48%) in CO electroreduction.

Additive Margin Softmax for Face Verification.

Abstract: In this letter, we propose a conceptually simple and intuitive learning objective function, i.e., additive margin softmax, for face verification. In general, face verification tasks can be viewed as metric learning problems, even though lots of face verification models are trained in classification schemes. It is possible when a large-margin strategy is introduced into the classification model to encourage intraclass variance minimization. As one alternative, angular softmax has been proposed to incorporate the margin. In this letter, we introduce another kind of margin to the softmax loss function, which is more intuitive and interpretable. Experiments on LFW and MegaFace show that our algorithm performs better when the evaluation criteria are designed for very low false alarm rate.

Perovskite Solar Cells with ZnO Electron-Transporting Materials

Abstract: Perovskite solar cells (PSCs) have developed rapidly over the past few years, and the power conversion efficiency of PSCs has exceeded 20%. Such high performance can be attributed to the unique properties of perovskite materials, such as high absorption over the visible range and long diffusion length. Due to the different diffusion lengths of holes and electrons, electron transporting materials (ETMs) used in PSCs play a critical role in PSCs performance. As an alternative to TiO2 ETM, ZnO materials have similar physical properties to TiO2 but with much higher electron mobility. In addition, there are many simple and facile methods to fabricate ZnO nanomaterials with low cost and energy consumption. This review focuses on recent developments in the use of ZnO ETM for PSCs. The fabrication methods of ZnO materials are briefly introduced. The influence of different ZnO ETMs on performance of PSCs is then reviewed. The limitations of ZnO ETM-based PSCs and some solutions to these challenges are also discussed. The review provides a systematic and comprehensive understanding of the influence of different ZnO ETMs on PSCs performance and potentially motivates further development of PSCs by extending the knowledge of ZnO-based PSCs to TiO2 -based PSCs.

Ultra-long high-sensitivity Φ-OTDR for high spatial resolution intrusion detection of pipelines

Abstract: An ultra-long phase-sensitive optical time domain reflectometry (Φ-OTDR) that can achieve high-sensitivity intrusion detection over 131.5km fiber with high spatial resolution of 8m is presented, which is the longest Φ-OTDR reported to date, to the best of our knowledge. It is found that the combination of distributed Raman amplification with heterodyne detection can extend the sensing distance and enhances the sensitivity substantially, leading to the realization of ultra-long Φ-OTDR with high sensitivity and spatial resolution. Furthermore, the feasibility of applying such an ultra-long Φ-OTDR to pipeline security monitoring is demonstrated and the features of intrusion signal can be extracted with improved SNR by using the wavelet detrending/denoising method proposed.