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The Scanning Secondary Moire Method with Atomic-Level Resolution and Large Micrometer-Scale Field of View

Acta Mechanica Solida Sinica 2025年第2期38卷 300-308页

作者： Yao Zhao Yueyue Xu Zhanwei Liu Jiangfan Zhou Han Liu Jianxin Nie Jinzhao Zhao Avic Changcheng Institute of Metrology&Measurement Beijing100095China State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of TechnologyBeijing100081China School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081China Beijing Institute of Structure and Environment Engineering Beijing100076China

The measurement field of view of the conventional transmission electron microscopy(TEM)nano-moiréand scanning transmission electron microscopy(STEM)nano-moirémethods is limited to the hundred-nanometer scale,unable to meet the deformation field measurement requirements of micrometer-scale materials such as transistors and *** paper proposed a novel measurement method based on scanning secondary moire,which can realize cross-scale deformation field measurement from nanometers to micrometers and solve the problem of insufficient measurement accuracy when using only the TEM moire *** method utilized the electron wave in the TEM passing through the atomic lattice of two layers of different materials to generate TEM *** this basis,the TEM was tuned to the STEM mode,and by adjusting parameters such as the amount of defocusing,magnification,scanning angle,etc.,the electron beam was focused on the position near the interface of the two layers of materials,and at the same time,the scanning line was made approximately parallel to the direction of one of the TEM moire *** scanning secondary moire patterns were generated when the scanning spacing was close to the TEM moire *** this method,the deformation field,mechanical properties,and internal defects of crystals can be detected by a large field of view with high sensitivity and high *** to traditional methods,the advantages of scanning secondary moire method lie in significantly improving the measurement field of TEM moire and STEM moire methods,realizing the cross-scale visualization measurement from nanometers to micrometers,and possessing atomic-level displacement measurement *** can also simplify and efficiently identify dislocations,offering a new method for large-area visualization observation of dislocation density in broad application prospects.

关键词： Nano-moire Scanning secondary moire Deformation fields Cross-scale visualization measurement Dislocation density

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Effects of thawing-induced softening on fracture behaviors of frozen rock

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Journal of Rock Mechanics and Geotechnical engineering 2024年第3期16卷 979-989页

作者： Ting Wang Hailiang Jia Qiang Sun Xianjun Tan Liyun Tang College of Geology and Environment Xi’an University of Science and TechnologyXi’an710054China College of Architecture and Civil Engineering Xi’an University of Science and TechnologyXi’an710054China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430064China

Due to the presence of ice and unfrozen water in pores of frozen rock,the rock fracture behaviors are susceptible to *** this study,the potential thawing-induced softening effects on the fracture behaviors of frozen rock is evaluated by testing the tension fracture toughness(KIC)of frozen rock at different temperatures(i.e.-20℃,-15℃,-12℃,-10℃,-8℃,-6℃,-4℃,-2℃,and 0℃).Acoustic emission(AE)and digital image correlation(DIC)methods are utilized to analyze the microcrack propagation during *** melting of pore ice is measured using nuclear magnetic resonance(NMR)*** results indicate that:(1)The KIC of frozen rock decreases moderately between-20℃ and-4℃,and rapidly between-4℃ and 0℃.(2)At-20℃ to-4℃,the fracturing process,deduced from the DIC results at the notch tip,exhibits three stages:elastic deformation,microcrack propagation and microcrack ***,at-4℃e0℃,only the latter two stages are observed.(3)At-4℃e0℃,the AE activities during fracturing are less than that at-20℃ to-4℃,while more small events are reported.(4)The NMR results demonstrate a reverse variation trend in pore ice content with increasing temperature,that is,a moderate decrease is followed by a sharp decrease and-4℃ is exactly the critical ***,we interpret the thawing-induced softening effect by linking the evolution in microscopic structure of frozen rock with its macroscopic fracture behaviors as follow:from-20℃ to-4℃,the thickening of the unfrozen water film diminishes the cementation strength between ice and rock skeleton,leading to the decrease in fracture ***-4℃ to 0℃,the cementation effect of ice almost vanishes,and the filling effect of pore ice is reduced significantly,which facilitates microcrack propagation and thus the easier fracture of frozen rocks.

关键词： Frozen sandstone Different thawing temperature Fracture toughness Microcrack propagation process Unfrozen water content

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Potentially Practical Catalytic Systems for Olefin-Polar Monomer Coordination Copolymerization

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CCS Chemistry 2024年第4期6卷 882-897页

作者： Chen Tan Min Chen Chen Zou Changle Chen Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationKey Laboratory of Environment-Friendly Polymeric Materials of Anhui ProvinceAnhui UniversityHefeiAnhui 230601 CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026

Studies on transition-metal catalyzed olefin-polar monomer coordination copolymerization and their resulting polar-functionalized polyolefin materials have attracted attention from both academia and *** decades of research,recent developments in a variety of high-performance catalytic systems have shown that this field is on the brink of *** review summarizes representative olefin-polar monomer coordination copolymerization catalyst systems that may be suitable for industrial polyolefin production via homogeneous solution-phase processes or heterogeneous gas-phase/slurry-phase processes.

关键词： olefin copolymerization polar monomer catalyst solution polymerization heterogeneous

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Hierarchical porous molybdenum carbide synergic morphological engineering towards broad multi-band tunable microwave absorption

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Nano Research 2024年第11期17卷 9845-9856页

作者： Tianbao Zhao Di Lan Zirui Jia Zhenguo Gao Guanglei Wu School of Materials Science and Engineering Hubei University of Automotive Technology Shiyan 442002 China Institute of Materials for Energy and Environment State Key Laboratory of Bio-fibers and Eco-textiles College of Materials Science and Engineering Qingdao University Qingdao 266071 China College of Chemistry and Chemical Engineering Qingdao University Qingdao 266071 China

With the accelerating development of electronic technology, how to effectively eliminate electromagnetic radiation pollution has become a critical issue. Electromagnetic wave (EMW) absorption materials have an irreplaceable position in the field of military stealth as well as in the field of electromagnetic pollution control. In order to cope with the complicated electromagnetic environment, the design of multifunctional and multiband high-efficiency EMW absorbers remains a daunting challenge. In this work, a hierarchical porous molybdenum carbide matrix with a three-dimensional porous structure was designed by salt melt synthesis (SMS) strategy. Furthermore, the relationship between the structure and the impedance matching performance was explored by stepwise modification via ultrathin layered MoS_(2) nanoflakes. Analysis indicates that the extent of modification of hierarchical porous molybdenum carbide by MoS_(2) nanoflakes modulates the dielectric performance due to differences in morphology and the introduction of heterogeneous structures, along with a dramatic impact on the impedance matching performance. In particular, the prepared MS/MC/PNC-2 composite exhibits a reflection loss (RL) of -55.30 dB at 2.4 mm, and an ultra-broad effective absorption bandwidth (EAB) of 7.60 GHz is obtained at 2.0 mm. The coordination of structure and component enables the absorber to exhibit strong absorption, wide bandwidth, thin thickness, and multi-band absorption characteristics. Noticeably, the effective absorption performance in the broadband for X and Ku is also satisfying, as well as possessing moderate marine anti-corrosion performance. This study contributes to an in-depth understanding of the relationship between impedance matching and EMW absorber performance and provides a reference for the design of multifunctional, multiband microwave absorbing materials.

关键词： electromagnetic wave absorber impedance matching multiband Schottky barrier

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Recent advances in interface engineering strategy for highly-efficient electrocatalytic water splitting

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InfoMat 2023年第1期5卷 62-94页

作者： Yunmei Du Bin Li Guangrui Xu Lei Wang Key Laboratory of Eco-chemical Engineering Ministry of EducationInternational Science and Technology Cooperation Base of Eco-chemical Engineering and Green ManufacturingQingdao University of Science and TechnologyQingdaoPeople's Republic of China Shandong Engineering Research Center for Marine Environment Corrosion and Safety Protection College of Environment and Safety EngineeringQingdao University of Science and TechnologyQingdaoPeople's Republic of China

The hydrogen energy generated by the electrocatalytic water splitting reaction has been established as a renewable and clean energy carrier with ultra-high energy density,which can well make up for shortcomings of conventional renewable energy sources,such as geographical limitations,climatic depen-dence,and energy ***,the introduction of electrocatalysts can enhance the efficiency of the water splitting process to generate ***,the heterostructure electrocatalysts constructed by coupling mul-tiple components(or phases)have emerged as the most promising option for water splitting due to the well-known electronic and synergistic *** existing reviews on interface engineering for electrocatalyst design mostly focus on the relationship between the heterostructures and specific electrocatalytic ***,a comprehensive overview of the integra-tion of model building,directional synthesis,and electrocatalytic mechanism has been rarely *** this end,in this review,the development of heterostructure catalysts is systematically introduced from the perspective of interface classification,interface growth and synthesis,and regulation of electrocatalytic performance based on the interfacial microenvironment(bonding,electronic configuration,lattice strain,etc.),thereby offering useful insights on the design and construction of interfacial ***,com-bined with the current development and applications of interface engineering strategies,the challenges of future heterostructure catalysts are discussed and relevant solutions are ***,this review can serve as a useful theo-retical reference for the integration of interfacial model building,directional synthesis,and electrocatalytic mechanism,which can further promote the development of hydrogen production technologies with low energy consump-tion and high yield.

关键词： electrocatalysis heterostructure interface engineering water splitting

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Developing modified k–εturbulence models for neutral atmospheric boundary layer flow simulation using OpenFOAM

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Building Simulation 2024年第12期17卷 2281-2295页

作者： Yuanbo Wang Jiqin Li Wei Liu Jiankai Dong Jing Liu School of Architecture Harbin Institute of TechnologyKey Laboratory of Cold Region Urban and Rural Human Settlement Environment Science and TechnologyMinistry of Industry and Information TechnologyHarbin 150090China Tianjin Key Laboratory of Indoor Air Environmental Quality Control School of Environmental Science and EngineeringTianjin University92 Weijin RoadTianjin 300072China Division of Sustainable Buildings Department of Civil and Architectural EngineeringKTH Royal Institute of TechnologyBrinellvägen 2310044 StockholmSweden

Accurate turbulence modeling is essential for simulation studies of urban *** this study,the comprehensive atmospheric boundary layer(ABL)model involving a variable model coefficient and an additional turbulent dissipation source term was implemented using the open-source software *** with consistent inlet wind profiles and rough wall functions of different turbulence variables based on the aerodynamic roughness,the model maintained the horizontal homogeneity ***,a hybrid approach was introduced to consider buildings immersed in ABL flows,enabling automatic transformation of the turbulence model between the region around the buildings and the free flow region away from any ***,the effects of applying different model forms to the airflow field around buildings were evaluated in detail through three-dimensional building cases representing six urban prototypes based on three wind tunnel *** findings indicated that all modified k–εmodels perform well in reproducing the flow data of the CEDVAL and Architectural Institute of Japan(AIJ)experiments consisting of a single building,an array of buildings,and an isolated high-rise ***,the modified k–εmodel with an additional correction term performed poorly in the database of Niigata Institute of technology and the case of complex terrain and urban building configurations,because the correction term inhibited the generation of turbulent kinetic *** addition,from the comparison between the experimental data of all cases,the model with the original formulation of the coefficient performed the best in terms of prediction *** root mean square errors of the normalized velocity were 0.1250,0.0879,0.1145,0.1350,and 0.1492 in different cases,which proved the reliability of this turbulence model.

关键词： urban airflow computational fluid dynamics(CFD) atmospheric boundary layer OpenFOAM turbulence model

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Effect of the mineral spatial distribution heterogeneity on the tensile strength of granite:Insights from PFC3D-GBM numerical analysis

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Journal of Rock Mechanics and Geotechnical engineering 2023年第5期15卷 1144-1160页

作者： Tao Zhang Liyuan Yu Yuxuan Peng Hongwen Jing Haijian Su Jiangbo Wei State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221116China College of Geology and Environment Xi’an University of Science and TechnologyXi’an710054China

The mechanical characteristics of crystalline rocks are affected by the heterogeneity of the spatial distribution of *** this paper,a novel three-dimensional(3D)grain-based model(GBM)based on particle flow code(PFC),***3D-GBM,is *** model can accomplish the grouping of mineral grains at the 3D scale and then filling ***,the effect of the position distribution,geometric size,and volume composite of mineral grains on the cracking behaviour and macroscopic properties of granite are examined by conducting Brazilian splitting *** numerical results show that when an external load is applied to a sample,force chains will form around each contact,and the orientation distribution of the force chains is uniform,which is independent of the external load ***,the number of high-strength force chains is proportional to the external load level,and the main orientation distribution is consistent with the external loading *** main orientation of the cracks is vertical to that of the high-strength force *** geometric size of the mineral grains controls the mechanical *** the average grain size increases,the number of transgranular contacts with higher bonding strength in the region connecting both loading points *** number of high-strength force chains increases,leading to an increase in the stress concentration value required for the macroscopic failure of the *** to the highest bonding strength,the generation of transgranular cracks in quartz requires a higher concentrated stress *** increasing volume composition of quartz,the number of transgranular cracks in quartz distributed in the region connecting both loading points increases,which requires many high-strength force *** load level rises,leading to an increase in the tensile strength of the numerical sample.

关键词： Rock mechanics Tensile strength Spatial distribution of minerals Three-dimensional(3D)grain-based model (GBM) Transgranular contact

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Self-assembly tungsten selenide hybrid ternary MOF derived magnetic alloys via multi-polarization to boost microwave absorption

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Nano Research 2024年第3期17卷 1625-1635页

作者： Tianbao Zhao Tingting Zheng Di Lan Yan Zhang Zhengshuo Sun Chao Wang Zirui Jia Guanglei Wu Institute of Materials for Energy and Environment State Key Laboratory of Bio-fibers and Eco-textilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China School of Materials Science and Engineering Hubei University of Automotive TechnologyShiyan 442002China College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071China

Confronted with severe electromagnetic wave pollution,the development of high-performance electromagnetic wave shielding or absorbing materials is an effective way to deal with ***,double transition metal alloys and transition metal dichalcogenides have attracted extensive attention in electromagnetic wave absorption,but few reports have studied the effects of these two materials on electromagnetic wave absorption at the same *** this work,cobalt-based alloy with magnetic loss mechanism was selected for composition *** ternary metal-organic framework was prepared by the one-step method,and then CoCu/C was prepared by high temperature ***,in the hydrothermal process,ultra-thin tungsten selenide nanosheets were coated on the surface of magnetic component,and the final polyhedral WSe_(2)/CoCu/C composites with multiple heterogeneous interfaces were *** synergistic effect of dielectric and magnetic components optimizes impedance matching and allows more electromagnetic waves to enter the ***,through the conduction loss of high conductivity graphitized carbon,interfacial polarization,and dipole polarization of heterogeneous interfaces between the components,the magnetic loss provided by CoCu alloy can work together to maximize the attenuation ability of electromagnetic ***,the minimum reflection loss(RLmin)value of the composite reaches-53.43 dB when the matched thickness is 2.1 mm,while the maximum effective absorption bandwidth(EABmax)reaches 6.0 GHz at a thin thickness of 1.8 *** work provides some support and reference for the design of novel electromagnetic wave absorbing materials via the dielectric/magnetic loss synergistic mechanism.

关键词： metal-organic framework dielectric/magnetic loss transition metal dichalcogenide electromagnetic wave absorption

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A novel order-reduced thermal-coupling electrochemical model for lithium-ion batteries

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Chinese Physics B 2024年第5期33卷 637-654页

作者：谢奕展王舒慧王震坡程夕明 School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China National Engineering Research Center for Electric Vehicles Beijing Institute of TechnologyBeijing 100081China The Hong Kong University of Science and Technology (Guangzhou) Sustainable Energy and Environment Thrust and Guangzhou MunicipalKey Laboratory of Materials InformaticsGuangzhou 511400China

Although the single-particle model enhanced with electrolyte dynamics(SPMe)is simplified from the pseudo-twodimensional(P2D)electrochemical model for lithium-ion batteries,it is difficult to solve the partial differential equations of solid–liquid phases in real-time ***,working temperatures have a heavy impact on the battery ***,a thermal-coupling SPMe is ***,a lumped thermal model is established to estimate battery *** order of the SPMe model is reduced by using both transfer functions and truncation techniques and merged with Arrhenius equations for thermal *** polarization voltage drop is then modified through the use of test data because its original model is unreliable ***,the coupling-model parameters are extracted using genetic *** results demonstrate that the proposed model produces average errors of about 42 mV under 15 constant current conditions and 15 mV under nine dynamic conditions,*** new electrochemicalthermal coupling model is reliable and expected to be used for onboard applications.

关键词： lithium-ion batteries order-reduced electrochemical models SPMe thermal-coupling model transient polarization voltage drop

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A new formula of recovery factor for non-equilibrium transport of graded suspended sediment in the Middle Yangtze River

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Journal of Mountain science 2023年第1期20卷 87-100页

作者： LI Lin-lin XIA Jun-qiang ZHOU Mei-rong DENG Shan-shan LI Zhi-wei State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China School of Civil Engineering Architecture and EnvironmentHubei University of TechnologyWuhan430068China

Suspended sediment concentrations in the Middle Yangtze River(MYR)reduced greatly after the Three Gorges Project operation,causing the composition of bed material to coarsen ***,little is known about the non-equilibrium transport of graded suspended sediment owing to different bed material compositions(BMCs)along the MYR,and it is necessary to determine the magnitude of recovery *** the Markov stochastic process in conjunction with the hiding-exposure effect of non-uniform bed-material,a new formula is proposed for calculating the recovery factor including the effect of different BMCs,and it is incorporated into the non-equilibrium transport equation to simulate the recovery processes of suspended load in both sand-gravel bed and sand bed reaches of the *** results show that:(i)the recovery rate of graded sediment concentrations at Zhicheng was slower than that at Shashi during the period 2003-2007;(ii)the mean recovery factors of the coarse,medium,and fine sediment fractions in the ZhichengShashi reach were 0.152,0.0012,and 0.0005,respectively,and the coarse sediment recovered up to the maximum sediment concentration of 0.138 kg/m3over a distance of 15 km;and(iii)the results of the new formula that can consider the effect of bed material composition are in general agreement with the field observations,and the spatial and temporal delay effects are inversely related to particle size and ***,the BMC effect on the nonequilibrium sediment transport in different reaches of the MYR needs to be considered for higher simulation accuracy.

关键词： non-equilibrium sediment transport bed material composition transition probability recovery factor Middle Yangtze River

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