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Elucidating the structure-activity relationship of Cu-Ag bimetallic catalysts for electrochemical CO_(2) reduction

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journal of Energy Chemistry 2024年第6期93卷 345-351,I0009页

作者： Qining Huang Lili wan Qingxuan Ren jingshan Luo Institute of Photoelectronic Thin film Devices and Technology State Key Laboratory of Photovoltaic Materials and CellsKey Laboratory of Photoelectronic Thin Film Devices and Technology of TianjinMinistry of Education Engineering Research Center of Thin Film Photoelectronic TechnologyNankai UniversityTianjin 300350China frontiers Science Center for New Organic Matter Nankai UniversityTianjin 300071China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

Developing bimetallic catalysts is an effective strategy for enhancing the activity and selectivity of electrochemical CO_(2) reduction reactions,where understanding the structure-activity relationship is essential for catalyst ***,we prepared two Cu-Ag bimetallic catalysts with Ag nanoparticles attached to the top or the bottom of Cu *** tested in a flow cell,the Cu-Ag catalyst with Ag nanoparticles on the bottom achieved a faradaic efficiency of 54%for ethylene production,much higher than the catalyst with Ag nanoparticles on the *** catalysts were further studied in the H-cell and zero-gap MEA *** was found that placing the two metals in the intensified reaction zone is crucial to triggering the tandem reaction of bimetallic *** work elucidates the structure-activity relationship of bimetallic catalysts for CO_(2) reduction and demonstrates the importance of considering both catalyst structures and cell characteristics to achieve high activity and selectivity.

关键词： Electrochemical CO_(2)reduction Bimetallic catalyst Cu-Ag Structure-activity relationship

Toward qualification of additively manufactured metal parts:Tensile and fatigue properties of selective laser melted Inconel 718 evaluated using miniature specimens

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journal of Materials Science & Technology 2022年第2期97卷 239-253页

作者： H.Y.wan W.K.Yang L.Y.wang Z.j.Zhou C.P.Li G.f.Chen L.M.Lei G.P.Zhang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Materials&Manufacturing Qualification Group Corporate TechnologySiemens Ltd.Beijing 100102China AECC Shanghai Commercial Aircraft Engine Manufacturing Co. LtdShanghai 201306China

Combined with the topology optimization,additive manufacturing can be used to fabricate metal parts with complex ***,due to the geometrical variations and microstructure heterogeneities of the additively manufactured metal parts,new standards with the use of miniature specimens are required for the evalutation of the spatial distribution of mechanical properties throughout the ***,we conduct a systematic investigation on tensile and fatigue properties of selective laser melted Inconel718 specimens with different thicknesses ranging from 0.1 mm to 1 mm.A“microstructure unit”that can well reflect the microstructure characteristic of selective laser melted materials is *** results reveal that premature necking with a dramatic drop in uniform elongation occurs if the ratio(t/d)of specimen thickness(t)to the"microstructure unit"size(d)is less than *** necking is mainly attributed to the transition of strain localization *** also propose a probabilistic statistical model for fatigue limit prediction based on the available fatigue *** is recommended that the criterion of t/d≥4 should be satisfied to ensure that the yield strength,the uniform elongation,and the fatigue limit determined by the miniature specimens are comparable with those determined by standard *** findings may provdie a guide to the establishment of miniature specimen-based standards toward the qualification of additively manufactured metal parts.

关键词： Selective laser melting Inconel 718 Miniature specimen Microstructure unit Thickness effect

Mesozoic-Cenozoic Tectonics of the Yellow Sea and Oil-Gas Exploration

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Acta Geologica Sinica(English Edition) 2010年第1期84卷 77-90页

作者： wan Tianfeng HAO Tianyao China University of Geosciences Beijing 100083 China Institute of Geology and Geophysics the Chinese Academy of Sciences Beijing 100101 China

The purpose of the present study was to study the tectonics of the Yellow Sea. Although oilgas exploration has been undertaken for more than 30 years in the southern Yellow Sea, the exploration progress has achieved little. There are three tectonic periods with near N-S trending shortening and compression （260-200 Ma, 135-52 Ma and 23-0.78 Ma） and three tectonic periods with near E-W trending shortening and compression （200-135 Ma, 52--23 Ma and 0.78 Ma） at the Yellow Sea and adjacent areas during the Mesozoic and Cenozoic. The lndosinian tectonic period is the collision period between the Sino-Korean and Yangtze Plates, which formed the basic tectonic framework for the Yellow Sea area. There were strong intraplate deformations during the Yanshanian （200-135 Ma） and Sichuanian （135-52 Ma） periods with different tectonic models, which are also the main formation periods for endogenic metallic mineral deposits around the Yellow Sea. The three tectonic periods during the Cenozoic affect important influences for forming oil-gas reservoirs. The Eocene-Oligocene （52-23 Ma） is the main forming period for oil-gas sources. The Miocene-Early Pleistocene （23-0.78 Ma） was a period of favorable passage for oil-gas migration along NNE trending faults. Since the Middle Pleistocene （0.78 Ma） the NNE trending faults are closed and make good conditions for the reservation of oil-gas. The authors suggest that we pay more attention to the oil-gas exploration at the intersections between the NNE trending existing faults and Paleogene- Neogene systems in the southern Yellow Sea area.

关键词： tectonics stress field oil-gas exploration Mesozoic-Cenozoic Yellow Sea

Numerical investigation of the factors influencing the vertical profiles of current,salinity,and SSC within a turbidity maximum zone

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International journal of Sediment Research 2017年第1期32卷 20-33页

作者： Yuanyang wan Li wang Shanghai Estuarine and Coastal Science Research Center International Marine and Dredging Consultants

The flow-sediment interaction plays a considerable role on the vertical(internal) profiles of current,salinity and suspended sediment concentration(SSC) within a turbidity maximum zone(TMZ).Numerical modeling provides valuable insights into the complex estuarine physical *** combining numerical modeling with field observations,the influencing factors of fine sediment dynamics within the TMZ of Yangtze Estuary have been explored in this ***,during the neap tide,the measured data present that the current is too weak to break the density stratification,and the vertical flow structure is effectively ***,a three-dimensional numerical model based on the Delft3 D has been developed and a range of numerical sensitivity analyses were carried out to distinguish the dominant mechanisms and physical processes responsible for the phenomena observed from the measurement *** numerical investigation highlights the following findings.(1) The vertical profile of currents within the TMZ is largely affected by saltwater intrusion,especially during lower currents when the baroclinic pressure gradient can significantly reshape the local vertical profiles of velocity.(2) The baroclinic effects are primarily determined by the stratification of salinity.(3) In addition to salinity,SSC also influences the local density stratification when its contribution to fluid density is comparable to that of salinity.(4) The settling velocity determines the overall sediment distribution and vertical profiles of the SSC in the water *** SSC-dependent settling velocity(including the flocculation-induced acceleration and hindered settling deceleration phases) affects the longitudinal movement of the sediments.(5) The vertical profiles of current,salinity and SSC within the TMZ are highly associated with the turbulence determined by the *** approach to modulate the vertical eddy viscosity in the model,based on the empirical dependency between Rigand Prt,may

关键词： Turbidity maximum zone(TMZ) fine sediment Residual circulation Yangtze Estuary Modelling Tidal asymmetry Stratification Turbulence Salinity

Numerical study of vibrations of a vertical tension riser excited at the top end

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journal of Ocean Engineering and Science 2017年第4期2卷 268-278页

作者： Bowen fu Decheng wan State Key Laboratory of Ocean Engineering School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityCollaborative Innovation Center for Advanced Ship and Deep-Sea ExplorationShanghai 200240China

This paper presents numerical simulations of vortex-induced vibrations of a vertical riser which is sinusoidally excited at its top end in both one and two directions in still water.A computational fluid dynamics method based on the strip theory is *** riser’s responses to both top-end and two-end excitations are carefully *** low reduced velocity cases,the in-line vibrations consist of three components,the low-frequency oscillation,the first-natural-frequency vibration during the riser reversal,and the second-natural-frequency vibration due to vortex *** sheared oscillatory flow along the span causes low-frequency oscillations in higher modes in the in-line direction,thus forming‘X’shaped,‘II’shaped,and‘O’shaped trajectories at various positions along the span when the riser is excited at its top end in one *** the presence of excitations in the other direction,more complex trajectories appear.

关键词： Vortex-induced vibration Oscillatory flow Riser Platform motion Viv-fOAM-SjTU solver

Inconsistent interspecific and intraspecific differentiation of climate envelopes in a subtropical tree

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journal of Plant Ecology 2019年第1期12卷 176-185页

作者： Qiuchi wan Zhuo Zheng Marta Benito-Garzón Rémy j.Petit School of Earth Science and Geological Engineering Sun Yat-sen University135 Xingang RoadHaizhu DistrictGuangzhou 510275China Biogeco INRAUniversity of Bordeaux69 Arcachon Road33610 CestasFrance

Aims Comparisons of climate envelopes among species have shown that niche conservatism tends to break down over ***,we use the Asian tree genus Platycarya(juglandaceae)as a case study to test this tendency at relatively short timescales in a single ***,together with a reanalysis of the extant literature,should help evaluate prospects of using correlations between climate and spe-cies occurrence data to infer evolutionary *** We rely on species distribution models(SDMs)and multivari-ate analyses to compare current and past(Last Glacial Maximum~21ka)climatic envelopes between the two extant Platycarya spe-cies(Platycarya strobilacea and Platycarya longipes)and between mainland and Taiwan populations of ***,paying particu-lar attention to autocorrelation *** also review interpreta-tions provided in similar studies comparing climate envelopes between and within species,including in studies involving native and introduced populations of the same *** findings We find intraspecific but not interspecific differentiation in climate envelopes of Platycarya,despite the prediction that niche differen-tiation should be stronger between older *** review also suggests that differentiation in climate envelopes need not imply rapid evolutionary *** SDMs can be used to raise evolutionary hypotheses to be validated with other data,we con-clude that it should not be used to directly infer short-term evolu-tionary processes.

关键词： climate envelope Last Glacial Maximum evolution Platycarya species distribution models

SHRIMP U-Pb dating for a K-bentonite bed in the Tieling formation,North China

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Chinese Science Bulletin 2010年第29期55卷 3312-3323页

作者： SU WenBo LI HuaiKun HUff W D ETTENSOHN f R ZHANG ShiHong ZHOU HongYing wan YuSheng School of Earth Sciences and Resources China University ofGeosciences (Beijing) Beijing 100083 China Tianjin Institute of Geology and Mineral Resources China Geological Survey Tianjin 300170 China Department of Geology University of Cincinnati Cincinnati OH 45221-0013 USA Department of Earth and Environment Sciences University of Kentucky Lexington KY 40506-0053 USA Beijing SHRIMP Center Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China

A SHRIMP U-Pb zircon age of 1437±21 Ma was obtained for a recently discovered K-bentonite bed in the Tieling formation,situated northeast of Beijing at the boundary between Liaoning and Hebei provinces,on the northern margin of the North China Craton(NCC).The SHRIMP U-Pb age places Tieling formation near the end of the Calymmian Period of the early Mesoproterozoic *** addition,a SHRIMP U-Pb zircon date of 1372±18 Ma was acquired for K-bentonite beds in the overlying,dark-shale-dominated Xiamaling formation from the same location northeast of *** date assigns a similar Mid-Mesoproterozoic(Ectasian Period) age for the Xiamaling formation,as have previously determined dates from other sections northwest of *** dates indicate that the Tieling and Xiamaling formations,as well as the related succession in the eastern part of the Yanshan Mountains,represented by the well-known Meso-to Neoproterozoic standard section in jixian,can be correlated well with sections northwest of Beijing in the western part of the Yanshan *** other words,the boundary between the Calymmian and Ectasian periods in the northern parts of the NCC is marked by the unconformity between the Tieling and Xiamaling formations in the northern *** boundary was previously ascribed to the "Qinyu Orogeny" and thought to be of Grenville *** this regard,the conventional "Qinyu Orogeny" should now be regarded as a short-lived regional uplift during Early Mesoproterozoic time,rather than a result from the Grenvillian assembly of the NCC to the Rodinia Supercontinent(～1.0 Ga).

关键词： SHRIMP 铁岭组膨润土 Pb 锆石中国 Rodinia超大陆中元古代早期

Microstructure evolution and mechanical properties of brazing joint for ultra-thin-walled Inconel 718 considering grain size effect and brazing temperature

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Chinese journal of Aeronautics 2024年第2期37卷 541-556页

作者： Rui ZHAO Yueshuai SONG Hui KANG Min wan School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China jiangxi Research Institute of Beihang University Jiangxi 330000China

The systematic investigation of the mechanical properties and microstructure evolution process of ultra-thin-walled Inconel 718 capillary brazing joints is of great significance because of the exceptionally high demands on its *** achieve this objective,this study investigates the impact of three distinct brazing temperatures and five typical grain sizes on the brazed joints’mechanical properties and microstructure evolution *** evolution analysis was conducted based on Electron Back Scatter Diffraction(EBSD),Scanning Electron Microscopy(SEM),X-Ray Diffraction(XRD),High-Resolution Transmission Electron Microscopy(HRTEM),and focused Ion Beam(fIB).Besides,the mechanical properties and fracture behavior were studied based on the uniaxial tension tests and in-situ tension *** findings reveal that the brazing joint’s strength is higher for the fine-grain capillary than the coarse-grain one,primarily due to the formation of a dense branch structure composed of G-phase in the brazing *** effects of grain size,such as pinning and splitting,are amplified at higher brazing ***,micro-cracks initiate around brittle intermetallic compounds and propagate through the eutectic zone,leading to a cleavage fracture *** fracture stress of fine-grain specimens is higher than that of coarse-grain due to the complex micro-crack ***,this study contributes significantly to the literature by highlighting the crucial impact of grain size on the brazing properties of ultra-thin-walled Inconel 718 structures.

关键词： EYWORDS Ultra-thin-walled structure Brazing Inconel 718 Grain size effect Brazing temperature

Multiple model predictive control of perching maneuver based on guardian maps

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Chinese journal of Aeronautics 2022年第5期35卷 347-360页

作者： Rui CAO Huiwen wan Zhen HE Yuping LU College of Automated Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Considering the strong nonlinearity of Unmanned Aerial Vehicles(UAVs)resulting from high Angle of Attack(AOA)and fast maneuvering,we present a multi-model predictive control strategy for UAV maneuvering,which has a small amount of online ***,we divide the maneuver envelope of UAV into several sub-regions on the basis of the gap metric theory.A novel algorithm is then developed to determine the ploytopic model for each *** to this,a Robust Model Predictive Control based on the Idea of Comprehensive optimization(ICE-RMPC)is *** control law is designed offline and optimized online to reduce the computational ***,the ICE-RMPC method is applied to design the controllers of *** addition,to guarantee the stability of whole closed-loop system,a multi-model switching control strategy based on guardian maps is put ***,the tracking performance of proposed control strategy is demonstrated by an illustrative example.

关键词： Guardian maps Model predictive control Multi-Model switching rule Online comprehensive design Perching maneuver