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Oxygen reduction electrocatalysis:From conventional to single-atomic platinum-based catalysts for proton exchange membrane fuel cells

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Frontiers in Energy 2024年第2期18卷 206-222页

作者： cheng YUAN Shiming ZHANG Jiujun ZHANG Institute for Sustainable Energy/College of Sciences Shanghai UniversityShanghai 200444China

Platinum(Pt)-based materials are still the most efficient and practical catalysts to drive the sluggish kinetics of cathodic oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).However,their catalysis and stability performance still need to be further improved in terms of corrosion of both carbon support and Pt catalyst particles as well as Pt loading *** on the developed synthetic strategies of alloying/nanostructuring Pt particles and modifying/innovating supports in developing conventional Pt-based catalysts,Pt single-atom catalysts(Pt SACs)as the recently burgeoning hot materials with a potential to achieve the maximum utilization of Pt are comprehensively reviewed in this *** design thoughts and synthesis of various isolated,alloyed,and nanoparticlecontained Pt SACs are *** single-atomic Pt coordinating with non-metals and alloying with metals as well as the metal-support interactions of Pt single-atoms with carbon/non-carbon supports are emphasized in terms of the ORR activity and stability of the *** advance further research and development of Pt SACs for viable implementation in PEMFCs,various technical challenges and several potential research directions are outlined.

关键词： oxygen reduction electrocatalysis Pt singleatom catalysts conventional Pt-based catalysts design thoughts and synthesis metal-support interactions

Nutrient transport following water transfer through the world's largest water diversion channel

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Journal of Environmental Sciences 2024年第1期135卷 703-714页

作者： Yuanhui cheng Hong Zhang Wei Yin State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085 China Changjiang Water Resources Protection Institute Wuhan 430051China University of Chinese Academy of Sciences Beijing 100049China

Nutrient levels in the artificial channel constructed for the Middle Route Project are significant indicators of water quality safety and aquatic ecological integrity for this large,interbasin ***,the distribution and transport of nutrients along the channel were poorly *** on a time-series dataset as well as mass balance and material flow analysis methods,the water and nutrient transport fluxes in the Middle Route of the South-to-North Water Diversion Project were identified in this *** results indicate that the nutrient concentrations varied considerably with time,but there was no significant difference among the 30 stations of the main *** temperature difference was the major factor in the large fluctuations of water quality indicators over *** nutrient loadings varied with the water volume outputs from the main channel to the waterreceiving *** deposition was an important source of nutrients in the main channel,accounting for 9.13%,20.6%,and 0.635%of the nitrogen,phosphorus,and sulfur input from the Danjiangkou Reservoir,*** 2021,a net accumulation of 988 tons of N,29 tons of P,and 2,540 tons of S,respectively,were present in the main *** increase of these external and internal nutrient loadings would cause water quality fluctuation and deterioration in some local sections of the main *** study quantified the spatial and temporal patterns of nutrient transport in the Middle Route and revealed the ecological effects on the aquatic environment,assisting authorities on the project to develop effective water conservation strategies.

关键词： Nutrient transport Spatiotemporal patterns The Middle Route The South-to-North Diversion Project Hydro-ecological effects Water-receiving cities

Unsupervised construction of health indicator for rotating machinery via multi-criterion feature selection and attentive variational autoencoder

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Science China(Technological Sciences) 2024年第5期67卷 1524-1537页

作者： LI XinYu cheng ChangMing PENG ZhiKe State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai200240China School of Mechanical Engineering Ningxia UniversityYinchuan750021China

Health indicator(HI)construction is a crucial task in degradation evaluation and facilitates the prognostic and health management(PHM)of rotating *** interference from artificial labeling,the HI construction approaches in an unsupervised manner have attracted substantial ***,current unsupervised methods generally struggle with two problems:(1)ignorance of both redundancy between features and global variability of features during the feature selection process;(2)inadequate utilization of information from different sampling *** tackle these problems,this work develops a novel unsupervised approach for HI construction that integrates multi-criterion feature selection and the Attentive Variational Autoencoder(Attentive VAE).Explicitly,a multi-criterion feature selection(Mc FS)algorithm together with an elaborately designed metric is proposed to determine a superior feature subset,considering the relevance,the redundancy,and the global variability of features ***,for the adequate utilization of the information from distinct sampling moments,a deep learning model named Attentive VAE is *** Attentive VAE is solely fed with the selected features in the health state for model training and the HI is derived through the reconstruction error to reveal the degradation degree of *** case studies based on genuine experimental datasets are involved to quantitatively evaluate the superiority of the developed approach,demonstrating its superiority over other unsupervised methods for characterizing degradation *** effectiveness of both the Mc FS algorithm and the Attentive VAE is verified by ablation experiments,respectively.

关键词： health indicator(HI) unsupervised learning multi-criterion feature selection global variability attention mechanism

Recent progress in functional modification and crosslinking of bioprosthetic heart valves

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Regenerative Biomaterials 2024年第1期3卷 1-16页

作者： cheng Zheng Li Yang Yunbing Wang National Engineering Research Center for Biomaterials Sichuan UniversityChengdu 610064China

Valvular heart disease(VHD),clinically manifested as stenosis and regurgitation of native heart valve,is one of the most prevalent cardiovascular diseases with high *** valve replacement surgery has been recognized as golden standard for the treatment of *** to the clinical application of transcatheter heart valve replacement technic and the excellent hemodynamic performance of bioprosthetic heart valves(BHVs),implantation of BHVs has been increasing over recent years and gradually became the preferred choice for the treatment of ***,BHVs might fail within 10-15 years due to structural valvular degeneration(SVD),which was greatly associated with drawbacks of glutaraldehyde crosslinked BHVs,including cytotoxicity,calcification,component degradation,mechanical failure,thrombosis and immune *** prolong the service life of BHVs,much effort has been devoted to overcoming the drawbacks of BHVs and reducing the risk of *** this review,we summarized and analyzed the research and progress on:(i)modification strategies based on glutaraldehyde crosslinked BHVs and(ii)nonglutaraldehyde crosslinking strategies for BHVs.

关键词： bioprosthetic heart valves modification crosslinking anticalcification antithrombosis

Microstructure recognition of steels by machine learning based on visual attention mechanism

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Journal of Iron and Steel Research International 2024年第4期31卷 909-923页

作者： Xing-yu Chen Lin cheng cheng-yang Hu Yu-peng Zhang Kai-ming Wu The State Key Laboratory of Refractories and Metallurgy Hubei Province Key Laboratory of Systems Science on Metallurgical ProcessingInternational Research Institute for Steel TechnologyCollaborative Center on Advanced SteelsWuhan University of Science and TechnologyWuhan 430081HubeiChina Metals Valley and Band(Foshan)Metallic Composite Materials Co. Ltd.Foshan 528000GuangdongChina

U-Net has achieved good performance with the small-scale datasets through skip connections to merge the features of the low-level layers and high-level layers and has been widely utilized in biomedical image segmentation as well as recent microstructure image segregation of the *** representative visual attention mechanism modules,named as squeeze-and-excitation networks,convolutional block attention module,and extended calibration algorithm,were intro-duced into the traditional U-Net architecture to further improve the prediction *** is found that compared with the original U-Net architecture,the evaluation index of the improved U-Net architecture has been significantly improved for the microstructure segmentation of the steels with the ferrite/martensite composite microstructure and pearlite/ferrite composite microstructure and the complex martensite/austenite island/bainite microstructure,which demonstrates the advantages of the utilization of the visual attention mechanism in the microstructure *** reasons for the accuracy improvement were discussed based on the feature maps analysis.

关键词： Microstructure recognition-Steel Machine learning Visual attention mechanism Visualization

Determining an optimal control strategy for anthropogenic VOC emissions in China based on source emissions and reactivity

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Journal of Environmental Sciences 2024年第2期136卷 248-260页

作者： Ruipeng Wang Xiaoqi Wang Shuiyuan cheng Jiaxian Zhu Xinyu Zhang Long cheng Kai Wang Key Laboratory of Beijing on Regional Air Pollution Control Faculty of Environment and LifeBeijing University of TechnologyBeijing 100124China

An evidence-based control strategy for emission reduction of VOC sources can effectively solve the regional PM2.5and O3compound pollution in *** estimated the anthropogenic VOC emission inventory in China in 2018 and established a source profile database containing 129 sources based on localized detection and the latest research ***,the distribution of the ozone formation potential(OFP)and secondary organic aerosol formation potential(SOAFP)for emission sources was ***,priority control routes for VOC emission sources were proposed for different *** VOC emissions in China reached 27,211.8 Gg in 2018,and small passenger cars,industrial protective coatings,biomass burning,heavy trucks,printing,asphalt paving,oil storage and transportation,coking,and oil refining were the main *** protective coatings,small passenger cars,and biomass burning all contributed significantly to OFP and *** in emission reduction control should be given to industrial protective coatings,small passenger cars,heavy trucks,coking,printing,asphalt paving,chemical fibers,and basic organic chemical sources over the medium and long term in *** addition,the priority control route for VOC emission sources should be adjusted according to the variations in VOC emission characteristics and regional differences,so as to obtain the maximum environmental benefits.

关键词： Volatile organic compounds Anthropogenic emission inventory Reactivity Emission projection Priority control route

Analysis of destructive effect of Zn on carbon brick and way of Zn into carbon brick

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Journal of Iron and Steel Research International 2024年第6期31卷 1344-1354页

作者： Peng-bo Liu Shu-sen cheng Yu-qing Xue Xiao-man cheng Zhao Liu University of Science and Technology Beijing Beijing 100083China Ministry of Ironmaking Shangdong Taishan Steel Group Co.Ltd.Taian 271000ShandongChina

The service life of a blast furnace depends largely on the degree of damage to the carbon brick in the *** brick and ramming material in the hearth of a 1780 m3 blast furnace after shutdown were sampled and *** was found that the substances in the cracks of the carbon brick near and above the taphole were ZnO and Zn_(2)SiO_(4),whereas the substances in the cracks of the carbon brick below the taphole were *** reaction of Zn with CO,SiO_(2),and Fes generates ZnO,Zn_(2)SiO_(4),and ZnS,resulting in volume expansion,which is an important reason for the cracking of carbon ***,several obvious Zn vapor flow channels were found in the ramming material,through which Zn vapor could enter the carbon brick,causing damage to the carbon *** the compactness of the ramming material is beneficial to preventing Zn vapor from entering the carbon brick through the voids in the ramming material,reducing the destructive effect of Zn on the carbon brick and further extending the service life of the blast furnace.

关键词： Zn Blast furnace Carbon brick Ramming material Crack

Prescribed-Time Fully Distributed Nash Equilibrium Seeking Strategy in Networked Games

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 261-263页

作者： cheng Qian Lei Ding the Institute of Advanced Technology for Carbon Neutrality College of Automation&the College of Artificial Intelligence Nanjing University of Posts and TelecommunicationsNanjing 210023China IEEE

Dear Editor, This letter is concerned with prescribed-time fully distributed Nash equilibrium seeking for networked games under directed graphs. An adaptive algorithm is proposed to ensure the convergence of all players to the Nash equilibrium without requiring any knowledge of global parameters. Moreover, it is theoretically proved that the convergence time of the proposed seeking strategy can be predefined based on practical requirements. Finally, a numerical example is presented to validate the effectiveness of the proposed method.

关键词： parameters seeking prescribed

Collectively induced transparency and absorption in waveguide quantum electrodynamics with Bragg atom arrays

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Communications in Theoretical Physics 2024年第8期76卷 19-28页

作者： Haolei cheng Wei Nie Center for Joint Quantum Studies and Department of Physics School of ScienceTianjin UniversityTianjin 300350China Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology Tianjin UniversityTianjin 300350China

Collective quantum states, such as subradiant and superradiant states, are useful for controlling optical responses in many-body quantum systems. In this work, we study novel collective quantum phenomena in waveguide-coupled Bragg atom arrays with inhomogeneous *** atoms without free-space dissipation, collectively induced transparency is produced by destructive quantum interference between subradiant and superradiant states. In a large Bragg atom array, multi-frequency photon transparency can be obtained by considering atoms with different frequencies. Interestingly, we find collectively induced absorption(CIA) by studying the influence of free-space dissipation on photon transport. Tunable atomic frequencies nontrivially modify decay rates of subradiant states. When the decay rate of a subradiant state equals to the free-space dissipation, photon absorption can reach a limit at a certain frequency. In other words, photon absorption is enhanced with low free-space dissipation, distinct from previous photon detection schemes. We also show multi-frequency CIA by properly adjusting atomic frequencies. Our work presents a way to manipulate collective quantum states and exotic optical properties in waveguide quantum electrodynamics(QED) systems.

关键词： waveguide quantum electrodynamics collective quantum states photon absorption Bragg atom array