Sustainable membrane-coated electrodes for CO2 electroreduction to methanol in alkaline media

CO2 electroreduction has high potential to combine carbon capture utilization and energy storage from renewable sources. The key challenge is the construction of highly efficient electrodes giving optimal CO2 conversion to high-value products. In this regard, research on electrode structures remains as an important task to face. Despite the advancements in gas diffusion electrodes (GDEs) to facilitate CO2 transfer and electrode efficiency, the catalyst is still vulnerable to be swept by the gas and liquid electrolyte, reducing the stability. We report the fabrication of novel membrane-coated electrodes (MCEs), by coating an anion exchange membrane over a copper (Cu):chitosan (CS) catalyst layer onto the carbon paper. CS and poly(vinyl) alcohol (PVA) were chosen for membrane preparation and catalyst binder, where Cu was embedded in the polymer matrix as nanoparticles or ion-exchanged in a layered stannosilicate or zeolite Y, to improve their hydrophilic, conductive, mechanical, and environmentally-friendly properties considered relevant to the sustainability of the electrode fabrication and performance. The intimate connection between the CS:PVA polymer membrane over-layer and the CS/Cu catalytic layer protects the MCEs from material losses, enhancing the CO2 conversion to methanol, even in high alkaline medium. A maximum Faraday Efficiency to methanol of 68.05% was achieved for the 10CuY/CS:PVA membrane over-layer.Financial support from the Spanish Ministry of Science and Universities under project grant CTQ2016-76231-C2-1-R is gratefully acknowledged

Quantum simulation of artificial Abelian gauge field using nitrogen-vacancy center ensembles coupled to superconducting resonators

We propose a potentially practical scheme to simulate artificial Abelian gauge field for polaritons using a hybrid quantum system consisting of nitrogen-vacancy center ensembles (NVEs) and superconducting transmission line resonators (TLR). In our case, the collective excitations of NVEs play the role of bosonic particles, and our multiport device tends to circulate polaritons in a behavior like a charged particle in an external magnetic field. We discuss the possibility of identifying signatures of the Hofstadter "butterfly" in the optical spectra of the resonators, and analyze the ground state crossover for different gauge fields. Our work opens new perspectives in quantum simulation of condensed matter and many-body physics using hybrid spin-ensemble circuit quantum electrodynamics system. The experimental feasibility and challenge are justified using currently available technology.Comment: 6 papes+supplementary materia

LCCT: a semisupervised model for sentiment classification

Conference Theme: Human Language TechnologiesAnalyzing public opinions towards products, services and social events is an important but challenging task. An accurate sentiment analyzer should take both lexicon-level information and corpus-level information into account. It also needs to exploit the domain-specific knowledge and utilize the common knowledge shared across domains. In addition, we want the algorithm being able to deal with missing labels and learning from incomplete sentiment lexicons. This paper presents a LCCT (Lexicon-based and Corpus-based, Co-Training) model for semi-supervised sentiment classification. The proposed method combines the idea of lexicon-based learning and corpus-based learning in a unified co-training framework. It is capable of incorporating both domain-specific and domain-independent knowledge. Extensive experiments show that it achieves very competitive classification accuracy, even with a small portion of labeled data. Comparing to state-of-the-art sentiment classification methods, the LCCT approach exhibits significantly better performances on a variety of datasets in both English and Chinese. © 2015 Association for Computational Linguisticspublished_or_final_versio

Solar gamma ray probe of local cosmic ray electrons

TeV-range cosmic ray electrons and positrons (CREs) have been directly measured in the search for new physics or unknown astrophysical sources. CREs can inverse-Compton scatter solar photons and boost their energies into gamma ray bands. Any potential CRE excess would enhance the resultant inverse Compton emission spectrum in the relevant energy range, offering a new window to verify the measured CRE spectrum. In this paper, we show that an excess in the TeV range of the CRE spectrum, such as the one indicated by the DAMPE experiment, can induce a characteristic solar gamma ray signal. Accounting for contamination from extragalactic gamma ray backgrounds (EGB), we forecast the DAMPE feature is testable ($\gtrsim 4 \sigma$) with a $\sim 10^{5}\,\mathrm{m}^2\,{\rm yr}$ exposure in the off-disk direction. This can be achieved by long-exposure observations of water Cherenkov telescopes, such as LHAASO (7.2 years) and HAWC (25.9 years).Comment: 6 pages, 4 figure

Experimental Long-Distance Decoy-State Quantum Key Distribution Based On Polarization Encoding

We demonstrate the decoy-state quantum key distribution (QKD) with one-way quantum communication in polarization space over 102km. Further, we simplify the experimental setup and use only one detector to implement the one-way decoy-state QKD over 75km, with the advantage to overcome the security loopholes due to the efficiency mismatch of detectors. Our experimental implementation can really offer the unconditionally secure final keys. We use 3 different intensities of 0, 0.2 and 0.6 for the pulses of source in our experiment. In order to eliminate the influences of polarization mode dispersion in the long-distance single-mode optical fiber, an automatic polarization compensation system is utilized to implement the active compensation.Comment: 4 pages,3 figure

Directional dual-band slotted semi-circular inverted-F antenna for WLAN applications

A simple and compact directional dual-band semi-circular inverted-F antenna for wireless local area network applications is reported. Two pairs of semi-circular slots as well as a pair of arms are employed to generate the dual resonances in the 2.4-2.48 and 5.2-5.8 GHz bands. The measured results show that the proposed antenna can provide two 10 dB impedance bandwidths of 160 MHz (2.40-2.56 GHz) and 900 MHz (4.95-5.85 GHz). Nearly constant directivities (about 4.7 dBi) are observed in the lower band, while directivities in the upper band vary between 6.3 and 8.6 dBi