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A thermodynamic perspective on electrode poisoning in solid oxide fuel cells

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1449-1455页

作者： kevin Huang Department of Mechanical Engineering University of South CarolinaColumbiaUSA

A critical challenge to the commercialization of clean and high-efficiency solid oxide fuel cell(SOFC)technology is the insuf-ficient stack lifespan caused by a variety of degradation mechanisms,which are associated with cell components and chemical *** components related degradation refers to thermal/chemical/electrochemical deterioration of cell materials under operating conditions,whereas the latter regards impurities in feedstocks of oxidant(air)and reductant(fuel).This article provides a thermodynamic perspective on the understanding of the impurities-induced degradation mechanisms in *** discussion focuses on using thermodynamic ana-lysis to elucidate poisoning mechanisms in cathodes by impurity species such as Cr,CO_(2),H_(2)O,and SO_(2) and in the anode by species such as S(or H_(2)S),SiO_(2),and p_(2)(or pH_(3)).The author hopes the presented fundamental insights can provide a theoretical foundation for search-ing for better technical solutions to address the critical degradation challenges.

关键词： impurities air fuel reaction activity

potential transformation of organic matter by microbes in cryoconite,Tibetan plateau

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Science China Earth Sciences 2024年第6期67卷 1978-1989页

作者： Bixi GUO Yongqin LIU kevin Xu ZHONG Quan SHI chen HE Qiang ZHENG Ruanhong CAI State Key Laboratory of Tibetan plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Center for the pan-Third pole Environment Lanzhou UniversityLanzhou 730000China Department of Earth Oceanand Atmospheric SciencesUniversity of British ColumbiaVancouverBC V6T 1Z4Canada State Key Laboratory of Heavy Oil processing Petroleum Molecules Engineering Center(PMEC)China University of PetroleumBeijing 102249China State Key Laboratory for Marine Environmental Science Collage of Ocean and Earth SciencesXiamen UniversityXiamen 361102China Fujian Key Laboratory of Marine Carbon Sequestration Xiamen UniversityXiamen 361005China

Microorganisms play an essential role in the glacier carbon cycle;how they transform organic matter in mountain glacial cryoconite remains to be ***,we applied ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)and deep sequencing of 16S rRNA gene,to investigate the temporal microbial transformation of dissolved organic matter(DOM)of the Tibetan plateau *** the 60-day incubation,we found that DOM in cryoconite underwent a three-stage transformation,with decreasing bioavailability over *** microbial community did not change much in the first week while degrading DOM molecules that were associated with higher H/C_(wa)and lower O/C_(wa).During days 15-30,DOM composition remained stable while microbial diversity *** day 60,the DOM was microbially converted into a higher state of recalcitrance,with higher values of aromatic index,O/C_(wa),and lower H/C_(wa),which contained molecules containing more *** among various microbial taxa,like Cyanobacteria,Bacteroidota,Gammaproteobacteria,Firmicutes,and Actinobacteriota,drove the DOM transformation in *** study sheds light on the in-situ transformation of DOM composition meditated by microbial populations in cryoconite at a temporal scale,providing new insights into understanding the microbial roles in the glacier organic carbon transformation.

关键词： Cryoconite Dissolved organic matter Biodegradation Microbial community Temporal variation

Batch Active Learning for Multispectral and Hyperspectral Image Segmentation Using Similarity Graphs

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1013-1033页

作者： Bohan chen kevin Miller Andrea L.Bertozzi Jon Schwenk Department of Mathematics University of CaliforniaLos Angeles520 Portola PlazaLosAngeles90095CAUSA Oden Institute for Computational Engineering and Sciences University of Texas at Austin201 E 24th StAustin 78712TXUSA Los Alamos National Laboratory Los AlamosNM 87545USA

Graph learning,when used as a semi-supervised learning(SSL)method,performs well for classification tasks with a low label *** provide a graph-based batch active learning pipeline for pixel/patch neighborhood multi-or hyperspectral image *** batch active learning approach selects a collection of unlabeled pixels that satisfy a graph local maximum constraint for the active learning acquisition function that determines the relative importance of each pixel to the *** work builds on recent advances in the design of novel active learning acquisition functions(e.g.,the Model Change approach in arXiv:2110.07739)while adding important further developments including patch-neighborhood image analysis and batch active learning methods to further increase the accuracy and greatly increase the computational efficiency of these *** addition to improvements in the accuracy,our approach can greatly reduce the number of labeled pixels needed to achieve the same level of the accuracy based on randomly selected labeled pixels.

关键词： Image segmentation Graph learning Batch active learning Hyperspectral image

Rational Design and Construction of a CdS QDs/InVO4 Atomic-Layer（110）/（110） Facet S-Scheme Heterojunction for Highly Efficient photocatalytic Degradation of C2H4

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Energy & Environmental Materials 2024年第3期7卷 215-222页

作者： Yuanpeng Dong peizhu Ji Xinyue Xu Rong Li Yin Wang kevin peter Homewood Xiaohong Xia Yun Gao Xuxing chen Ministry of Education Key Laboratory for the Green preparation and Application of Functional Materials School of Materials Science&Engineering Hubei University Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices Hubei University of Arts and Science State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences United Water (Xianning) Company Limited

Exploring high efficiency S-scheme heterojunction photocatalysts with strong redox ability for removing volatile organic compounds from the air is of great interest and ***,how to predict and regulate the transport of photogenerated carriers in heterojunctions is a great ***,density functional theory calculations were first used to successfully predict the formation of a CdS quantum dots/InVO4atomic-layer （110）/（110） facet S-scheme ***,a CdS quantum dots/InVO4atomic-layer was synthesized by in-situ loading of CdS quantum dots with （110） facets onto the（110） facets of *** a result of the deliberately constructed built-in electric field between the adjoining facets,we obtain a remarkably enhanced photocatalytic degradation rate for *** rate is 13.8 times that of pure CdS and 13.2 times that of pure ***-situ irradiated X-ray photoelectron spectroscopy,photoluminescence and time-resolved photoluminescence measurements were carried *** experiments validate that the built-in electric field enhanced the dissociation of photoexcited excitons and the separation of free charge carriers,and results in the formation of S-scheme charge transfer *** reaction mechanism of the photocatalytic C2H4oxidation is investigated by in-situ electron paramagnetic *** work provides a mechanistic insight into the construction and optimization of semiconductor heterojunction photocatalysts for application to environmental remediation.

关键词： CdS QDs InVO4 atomic-layer photocatalysis S-scheme volatile organic compounds

Integrated photonic fractional convolution accelerator

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photonics Research 2024年第8期12卷 1828-1839页

作者： kevin ZELAYA MOHAMMED-ALI MIRI Department of physics Queens College of the City University of New YorkQueensNew York 11367USA physics program The Graduate Center of the City University of New YorkNew YorkNew York 10016USA

An integrated photonic circuit architecture to perform a modified-convolution operation based on the discrete fractional Fourier transform(DFrFT) is introduced. This is accomplished by utilizing two nonuniformly coupled waveguide lattices with equally spaced eigenmode spectra, the lengths of which are chosen so that the DFrFT and its inverse operations are achieved. A programmable modulator array is interlaced so that the required fractional convolution operation is performed. Numerical simulations demonstrate that the proposed architecture can effectively perform smoothing and edge detection tasks even for noisy input signals, which is further verified by electromagnetic wave simulations. Notably, mild lattice defects do not jeopardize the architecture performance, showing its resilience to manufacturing errors.

关键词： fractional convolution utilizing

Bacterial microcompartment-mimicking pickering emulsion droplets for detoxification of chemical threats under sweet conditions

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Science China Chemistry 2024年第9期67卷 3039-3049页

作者： Xiao Xu Wenqi Xie Ting Wu chen chen Xiaoning chen Yuheng Yang Hao Lian Hao chen Xiaofeng cheng Zhitong chen Guojun chen Chaoqun Liu Lanlan chen Yu He Zhaowei chen Bernard p.Binks Huanghao Yang New Cornerstone Science Laboratory MOE Key Laboratory for Analytical Science of Food Safety and BiologyCollege of ChemistryFuzhou UniversityFuzhou 350002China Institute of Biomedical and Health Engineering Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China Department of Biomedical Engineering and the Rosalind&Morris Goodman Cancer Research Institute McGill UniversityMontreal QC H3A 1A3Canada School of pharmacy Henan UniversityKaifeng 475004China Department of Chemistry University of HullHull HU67RXUK

Chemical warfare agents represent a severe threat to mankind and their efficient decontamination is a global ***,traditional disposal strategies have limitations,including high energy consumption,use of aggressive reagents and generation of toxic ***,inspired by the compartmentalized architecture and detoxification mechanism of bacterial microcompartments,we constructed oil-in-water pickering emulsion droplets stabilized by hydrogen-bonded organic framework immobilized cascade enzymes for decontaminating mustard gas simulant(2-chloroethyl ethyl sulfide,CEES)under sweet *** exemplified droplet systems were developed with two-enzyme(glucose oxidase/chloroperoxidase)and threeenzyme(invertase/glucose oxidase/chloroperoxidase)cascades,both achieving over 6-fold enhancement in decontamination efficiency compared with free enzymes and>99% selectivity towards non-toxic *** found that the favored mass transfer of sugars and CEES from their respective phases to approach the cascade enzymes located at the droplet surface and the facilitated substrate channeling between proximally immobilized enzymes were key factors in augmenting the decontamination *** importantly,the robustness of immobilized enzymes enabled easy reproduction of both the droplet formation and detoxification performance over 10 cycles,following long-term storage and in far-field locations.

关键词： pickering emulsion biomimetics chemical warfare agent bacterial microcompartment biocatalysis

Femtosecond laser fabrication of nanograting-based distributed fiber sensors for extreme environmental applications

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International Journal of Extreme Manufacturing 2021年第2期3卷 139-152页

作者： Mohan Wang Kehao Zhao Jingyu Wu Yuqi Li Yang Yang Sheng Huang Jieru Zhao Thomas Tweedle David Carpenter Guiqiu Zheng Qingxu Yu kevin p chen Department of Electrical and Computer Engineering University of PittsburghPittsburghPA 15261United States of America School of Optoelectronic Engineering and Instrument Science Dalian University of TechnologyDalian 116081People’s Republic of China Westinghouse Electric Company LLC PittsburghPA 15235United States of America Nuclear Reactor Laboratory Massachusetts Institute of Technology138 Albany StreetCambridgeMA 02139United States of America

The femtosecond laser has emerged as a powerful tool for micro-and nanoscale device fabrication. Through nonlinear ionization processes, nanometer-sized material modifications can be inscribed in transparent materials for device fabrication. This paper describes femtosecond precision inscription of nanograting in silica fiber cores to form both distributed and point fiber sensors for sensing applications in extreme environmental conditions. Through the use of scanning electron microscope imaging and laser processing optimization,high-temperature stable, Type II femtosecond laser modifications were continuously inscribed,point by point, with only an insertion loss at 1 d B m~(-1) or 0.001 d B per point sensor ***-temperature performance of fiber sensors was tested at 1000℃, which showed a temperature fluctuation of ±5.5℃ over 5 days. The low laser-induced insertion loss in optical fibers enabled the fabrication of a 1.4 m, radiation-resilient distributed fiber sensor. The in-pile testing of the distributed fiber sensor further showed that fiber sensors can execute stable and distributed temperature measurements in extreme radiation environments. Overall, this paper demonstrates that femtosecond-laser-fabricated fiber sensors are suitable measurement devices for applications in extreme environments.

关键词： femtosecond laser manufacturing optical fiber sensor device fabrication extreme environment sensing

RepDNet:A re-parameterization despeckling network for autonomous underwater side-scan sonar imaging with prior-knowledge customized convolution

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Defence Technology（防务技术） 2024年第5期35卷 259-274页

作者： Zhuoyi Li Zhisen Wang Deshan chen Tsz Leung Yip Angelo p.Teixeira Department of Logistics and Maritime Studies The Hong Kong Polytechnic UniversityChina State Key Laboratory of Maritime Technology and Safety Wuhan University of TechnologyChina School of Transportation and Logistics Engineering Wuhan University of TechnologyChina National Engineering Research Center for Water Transport Safety Wuhan University of TechnologyChina Centre for Marine Technology and Ocean Engineering(CENTEC) Instituto Superior TecnicoUniversidade de LisboaPortugal

Side-scan sonar(SSS)is now a prevalent instrument for large-scale seafloor topography measurements,deployable on an autonomous underwater vehicle(AUV)to execute fully automated underwater acoustic scanning imaging along a predetermined ***,SSS images often suffer from speckle noise caused by mutual interference between echoes,and limited AUV computational resources further hinder noise *** approaches for SSS image processing and speckle noise reduction rely heavily on complex network structures and fail to combine the benefits of deep learning and domain *** address the problem,Rep DNet,a novel and effective despeckling convolutional neural network is *** DNet introduces two re-parameterized blocks:the pixel Smoothing Block(pSB)and Edge Enhancement Block(EEB),preserving edge information while attenuating speckle *** training,pSB and EEB manifest as double-layered multi-branch structures,integrating first-order and secondorder derivatives and smoothing *** inference,the branches are re-parameterized into a 3×3 convolution,enabling efficient inference without sacrificing *** DNet comprises three computational operations:3×3 convolution,element-wise summation and Rectified Linear Unit *** on benchmark datasets,a real SSS dataset and Data collected at Lake Mulan aestablish Rep DNet as a well-balanced network,meeting the AUV computational constraints in terms of performance and latency.

关键词： Side-scan sonar Sonar image despeckling Domain knowledge Re-parameterization

Effect of dry-wet cycles on dynamic properties and microstructures of sandstone:Experiments and modelling

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International Journal of Mining Science and Technology 2024年第5期34卷 655-679页

作者： Hai pu Qingyu Yi Andrey p.Jivkov Zhengfu Bian Weiqiang chen Jiangyu Wu State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Earth Engineering China University of Mining and TechnologyXuzhou 221116China Key Laboratory of Xinjiang Coal Resources Green Mining Ministry of EducationXinjiang Institute of EngineeringUrumqi 830023China Department of Solids and Structures School of EngineeringUniversity of ManchesterManchester M139PLUK School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhou 221116China Department of Civil and Environmental Engineering Rice UniversityHouston 77005USA State Key Laboratory of High performance Civil Engineering Materials Jiangsu Research Institute of Building Science Co.Ltd.Nanjing 210008China Department of Materials University of OxfordOxford OX13PHUK

Underground pumped storage power plant(UpSp)is an innovative concept for space recycling of abandoned *** realization requires better understanding of the dynamic performance and durability of reservoir *** paper conducted ultrasonic detection,split Hopkinson pressure bar(SHpB)impact,mercury intrusion porosimetry(MIp),and backscatter electron observation(BSE)tests to investigate the dynamical behaviour and microstructure of sandstone with cyclical dry-wet damage.A coupling FEM-DEM model was constructed for reappearing mesoscopic structure *** results show that dry-wet cycles decrease the dynamic compressive strength(DCS)with a maximum reduction of 39.40%,the elastic limit strength is reduced from 41.75 to 25.62 *** sieved fragments obtain the highest crack growth rate during the 23rd dry-wet cycle with a predictable life of 25 cycles for each rock *** pore fractal features of the macropores and micro-meso pores show great differences between the early and late cycles,which verifies the computational statistics analysis of particle *** numerical results show that the failure patterns are governed by the strain in pre-peak stage and the shear cracks are *** dry-wet cycles reduce the energy transfer efficiency and lead to the discretization of force chain and crack fields.

关键词： Underground pumped storage power plant Dry-wet cycles Split Hopkinson pressure bar Macro and micro properties FEM-DEM coupling model Damage characterization