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Microsystems & Nanoengineering 2024年第2期10卷 83-90页

作者： Shinji Bono Ryotaro Nakai Satoshi Konishi research Organization of Science and Technology Ritsumeikan UniversityShigaJapan Ritsumeikan Advanced research Academy KyotoJapan Ritsumeikan global innovation research Organization Ritsumeikan UniversityShigaJapan Graduate School of Science and Engineering Ritsumeikan UniversityShigaJapan

Implementing a signal-switching mechanism for the selective use of integrated sensors and actuators plays a crucial role in streamlining the functionality of miniaturized devices.Here,a liquid metal droplet(LMD)-based signal-switching mechanism is introduced to achieve such functionality.Pressure modulation with a 100-μm spatial resolution enabled precise control of the position of the LMDs within a channel.After integrating the channel with asymmetrically structured electrodes,the effect of the shuttle-like movement of LMD on the temporal changes in the overall capacitance was investigated.Consequently,analysis of the capacitive peaks revealed the directional movement of the LMDs,enabling estimation of the position of the LMDs without direct observation.In addition,we achieved successful signal extraction from the capacitive sensor that was linked to the activated electrodes,thereby enabling selective data retrieval.The proposed signal-switching mechanism method achieved a detection accuracy of~0.1 pF.The sensor’s ability to simultaneously detect the LMD position and generate a signal underscores its significant potential for multiplexing in multisensing systems,particularly in concealed environments,such as in vivo settings.

关键词： liquid thereby integrating

Unveiling of Terahertz Emission from Ultrafast Demagnetization and the Anomalous Hall Effect in a Single Ferromagnetic Film

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Chinese Physics Letters 2024年第4期41卷 45-50页

作者：蓝志强李章顺徐浩然刘凡金钻明彭滟朱亦鸣 Terahertz Technology innovation research institute Terahertz Spectrum and Imaging Technology Cooperative Innovation CenterShanghai Key Lab of Modern Optical SystemUniversity of Shanghai for Science and TechnologyShanghai 200093China

Using THz emission spectroscopy,we investigate the elementary spin dynamics in ferromagnetic single-layer Fe on a sub-picosecond timescale.We demonstrate that THz radiation changes its polarity with reversal of the magnetization applied by the external magnetic field.In addition,it is found that the sign of THz polarity excited from different sides is defined by the thickness of the Fe layer and Fe/dielectric interface.Based on the thickness and symmetry dependences of THz emission,we experimentally distinguish between the two major contributions:ultrafast demagnetization and the anomalous Hall effect.Our experimental results not only enrich understanding of THz electromagnetic generation induced by femtosecond laser pulses but also provide a practical way to access laser-induced ultrafast spin dynamics in magnetic structures.

关键词： magnetic magnetization polarity

Insight into the capacity degradation and structural evolution of single-crystal Ni-rich cathodes

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Journal of Energy Chemistry 2024年第8期95卷 68-76页

作者： Xiaodong Zhang Jiao Lin Ersha Fan Qingrong Huang Su Ma Renjie Chen Feng Wu Li Li Beijing Key Laboratory of Environmental Science and Engineering School of Materials Science and Engineering Beijing Institute of Technology Collaborative innovation Center of Electric Vehicles in Beijing Advanced Technology research institute Beijing Institute of Technology

Single-crystal Ni-rich cathodes are a promising candidate for high-energy lithium-ion batteries due to their higher structural and cycling stability than polycrystalline materials. However, the phase evolution and capacity degradation of these single-crystal cathodes during continuous lithation/delithation cycling remains unclear. Understanding the mapping relationship between the macroscopic electrochemical properties and the material physicochemical properties is crucial. Here, we investigate the correlation between the physical-chemical characteristics, phase transition, and capacity decay using capacity differential curve feature identification and in-situ X-ray spectroscopic imaging. We systematically clarify the dominant mechanism of phase evolution in aging cycling. Appropriately high cut-off voltages can mitigate the slow kinetic and electrochemical properties of single-crystal cathodes. We also find that second-order differential capacity discharge characteristic curves can be used to identify the crystal structure disorder of Ni-rich cathodes. These findings constitute a step forward in elucidating the correlation between the electrochemical extrinsic properties and the physicochemical intrinsic properties and provide new perspectives for failure analysis of layered electrode materials.

关键词： Capacity decay Differential capacity analysis Phase transition Single-crystal cathodes

Cerium refinement of grains and primary carbides during solidification of Cr_(4)Mo_(4)V bearing steel

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Journal of Rare Earths 2024年第4期42卷 783-792页

作者： Weifeng Liu Jianqiang Wang Mingyue Sun Bin Xu Jiahao Yao Qunbo Fan Dianzhong Li Chongqing innovation Center Beijing Institute of TechnologyChongqing401135China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

The effect of cerium(Ce)on the solidification microstructure of Cr_(4)Mo_(4)V bearing steel was investigated via a combined experimental and theoretical method.With a trace amount(0.056 wt%)of Ce addition,the coarse columnar grains in as-cast microstructure transform into equiaxed ones,and the average diameter is reduced from 56 to 27μm.The network-like and bulky primary MC and M2C carbides at the interdendritic regions become disconnected and refined,and their volume percentage decreases from4.15 vol%to 2.1 vol%.Ce-inclusions acting as heterogeneous nucleation agents of prior-austenite grains and Ce atoms segregating at grain boundaries,both contribute to the refinement of grains.Thermodynamic calculations reveal that primary carbides are precipitated afterγ-austenite forms near the end of the solidification process.The modification of primary carbides in size and amount is mainly attributed to the isolated remaining melt separated by refinedγ-austenite grains in which the nucleation of carbides is promoted,while the growth is restrained owing to the less segregation of alloying elements.

关键词： Cr_(4)Mo_(4)V bearing steel Rare Earths Grains Primary carbides Refinement

Lattice Boltzmann simulation study of anode degradation in solid oxide fuel cells during the initial aging process

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 405-411页

作者： Shixue Liu Zhijing Liu Shuxing Zhang Hao Wu Hydrogen Energy Industrial Technology innovation Center China Nuclear Power Technology Research InstituteShenzhen 518031China Shenzhen Engineering research Center for Hydrogen Safety Shenzhen 518031China

For present solid oxide fuel cells(SOFCs),rapid performance degradation is observed in the initial aging process,and the dis-cussion of the degradation mechanism necessitates quantitative analysis.Herein,focused ion beam-scanning electron microscopy was em-ployed to characterize and reconstruct the ceramic microstructures of SOFC anodes.The lattice Boltzmann method(LBM)simulation of multiphysical and electrochemical processes in the reconstructed models was performed.Two samples collected from industrial-size cells were characterized,including a reduced reference cell and a cell with an initial aging process.Statistical parameters of the reconstructed microstructures revealed a significant decrease in the active triple-phase boundary and Ni connectivity in the aged cell compared with the reference cell.The LBM simulation revealed that activity degradation is dominant compared with microstructural degradation during the initial aging process,and the electrochemical reactions spread to the support layer in the aged cell.The microstructural and activity de-gradations are attributed to Ni migration and coarsening.

关键词： solid oxide fuel cell anode degradation focused ion beam-scanning electron microscopy lattice Boltzmann method

Full-parameter omnidirectional transformation optical devices

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National Science Review 2024年第3期11卷 92-99页

作者： Yuan Gao Yu Luo Jingjing Zhang Zhengjie Huang Bin Zheng Hongsheng Chen Dexin Ye Interdisciplinary Center for Quantum Information State Key Laboratory of Extreme Photonics and InstrumentationZJU-Hangzhou Global Scientific and Technological Innovation CenterZhejiang University School of Electrical and Electronic Engineering Nanyang Technological University CNRS-InternationalNTU-Thales research Alliance Nanyang Technological University institute of Electromagnetic Space Southeast University State Key Laboratory of Millimeter Waves Southeast University International Joint innovation Center The Electromagnetics Academy at Zhejiang University Zhejiang University Key Laboratory of Advanced Micro/Nano Electronic Devices&Smart Systems of Zhejiang Jinhua Institute of Zhejiang UniversityZhejiang University Shaoxing institute of Zhejiang University Zhejiang University

Transformation optics(TO) provides an unprecedented technique to control electromagnetic(EM) waves by engineering the constitutive parameters of the surrounding medium through a proper spatial transformation. In general, ideal transformation optical devices require simultaneous electric and magnetic responses along all three dimensions. To ease the practical implementation, previous studies usually made use of reduced parameters or other simplified approaches, which inevitably introduce extra reflection or unwanted phase shift. Up to today, experimental realizations of full-parameter transformation optical devices in free space are still quite limited. Here, a general design strategy is proposed to solve this problem.As a specific example, a full-parameter spatial-compression TO medium with constitutive parameters taking the diagonal form diag(a, a, 1/a) for the TM wave incidence was designed and realized experimentally. Such spatial-compression TO media were then applied to the implementation of an ideal omnidirectional invisibility cloak capable of concealing a large-scale object over a wide range of illumination angles. Both the simulation and experiment confirm that the cloak allows for nearly unity transmission of EM waves in the forward direction without introducing extra scattering or phase shift. This work constitutes an important stepping stone for future practical implementation of arbitrary full-parameter omnidirectional transformation optical devices.

关键词： transformation optical devices omnidirectional impedance matching full-parameter invisibility cloak

A hybrid spatial-temporal deep learning prediction model of industrial methanol-to-olefins process

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 73-85页

作者： Jibin Zhou Xue Li Duiping Liu Feng Wang Tao Zhang Mao Ye Zhongmin Liu National Engineering research Center of Lower-Carbon Catalysis Technology Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Yulin innovation institute for Clean Energy Clean Energy Innovation Institute of Chinese Academy of SciencesYulin 719053China Xuelang Industrial Intelligence Technology Co. Ltd.Wuxi 214000China

Methanol-to-olefins,as a promising non-oil pathway for the synthesis of light olefins,has been successfully industrialized.The accurate prediction of process variables can yield significant benefits for advanced process control and optimization.The challenge of this task is underscored by the failure of traditional methods in capturing the complex characteristics of industrial processes,such as high nonlinearities,dynamics,and data distribution shift caused by diverse operating conditions.In this paper,we propose a novel hybrid spatial-temporal deep learning prediction model to address these issues.Firstly,a unique data normalization technique called reversible instance normalization is employed to solve the problem of different data distributions.Subsequently,convolutional neural network integrated with the self-attention mechanism are utilized to extract the temporal patterns.Meanwhile,a multi-graph convolutional network is leveraged to model the spatial interactions.Afterward,the extracted temporal and spatial features are fused as input into a fully connected neural network to complete the prediction.Finally,the outputs are denormalized to obtain the ultimate results.The monitoring results of the dynamic trends of process variables in an actual industrial methanol-to-olefins process demonstrate that our model not only achieves superior prediction performance but also can reveal complex spatial-temporal relationships using the learned attention matrices and adjacency matrices,making the model more interpretable.Lastly,this model is deployed onto an end-to-end Industrial Internet Platform,which achieves effective practical results.

关键词： methanol-to-olefins process variables prediction spatial-temporal self-attention mechanism graph convolutional network

Predict the evolution of mechanical property of Al-Li alloys in a marine environment

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Defence Technology（防务技术） 2024年第1期31卷 557-566页

作者： Wei Li Lin Xiang Guang Wu Hongli Si Jinyan Chen Yiming Jin Yan Su Jianquan Tao Chunyang Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100036China Chongqing innovation Center Beijing Institute of TechnologyChongqing400044China First research institute of the Ministry of Public Security for PR China Beijing100036China Southwest Technology and Engineering research institute Chongqing400039China

The ocean is one of the essential fields of national defense in the future,and more and more attention is paid to the lightweight research of Marine equipment and materials.This study it is to develop a Machine learning(ML)-based prediction method to study the evolution of the mechanical properties of Al-Li alloys in the marine environment.We obtained the mechanical properties of Al-Li alloy samples under uniaxial tensile deformation at different exposure times through Marine exposure experiments.We obtained the strain evolution by digital image correlation(DIC).The strain field images are voxelized using 2D-Convolutional Neural Networks(CNN)autoencoders as input data for Long Short-Term Memory(LSTM)neural networks.Then,the output data of LSTM neural networks combined with corrosion features were input into the Back Propagation(BP)neural network to predict the mechanical properties of Al-Li alloys.The main conclusions are as follows:1.The variation law of mechanical properties of2297-T8 in the Marine atmosphere is revealed.With the increase in outdoor exposure test time,the tensile elastic model of 2297-T8 changes slowly,within 10%,and the tensile yield stress changes significantly,with a maximum attenuation of 23.6%.2.The prediction model can predict the strain evolution and mechanical response simultaneously with an error of less than 5%.3.This study shows that a CNN/LSTM system based on machine learning can be built to capture the corrosion characteristics of Marine exposure experiments.The results show that the relationship between corrosion characteristics and mechanical response can be predicted without considering the microstructure evolution of metal materials.

关键词： Marine environment Al-Li alloy Machine learning Corrosion

Roles of Upper-Level Descending Inflow in Moat Development in Simulated Tropical Cyclones with Secondary Eyewall Formation

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Advances in Atmospheric Sciences 2024年第6期41卷 1100-1114页

作者： Nannan QIN Liguang WU Nanjing Joint institute for Atmospheric Sciences Nanjing 210041China Shanghai Typhoon institute China Meteorological AdministrationShanghai 200030China Department of Atmospheric and Oceanic Sciences and institute of Atmospheric Sciences Fudan UniversityShanghai 200438China innovation Center of Ocean and Atmosphere System Zhuhai Fudan Innovation Research InstituteZhuhai 518057China

This study investigated the effects of upper-level descending inflow(ULDI)associated with inner-eyewall convection on the formation of the moat in tropical cyclones(TCs)with secondary eyewall formation(SEF).In our numerical experiments,a clear moat with SEF occurred in TCs with a significant ULDI,while no SEF occurred in TCs without a significant ULDI.The eyewall convection developed more vigorously in the control run.A ULDI occurred outside the inner-eyewall convection,where it was symmetrically unstable.The ULDI was initially triggered by the diabatic warming released by the inner eyewall and later enhanced by the cooling below the anvil cloud.The ULDI penetrated the outer edge of the inner eyewall with relatively dry air and prevented excessive solid-phase hydrometeors from being advected further outward.It produced extensive sublimation cooling of falling hydrometeors between the eyewall and the outer convection.The sublimation cooling resulted in negative buoyancy and further induced strong subsidence between the eyewall and the outer convection.As a result,a clear moat was generated.Development of the moat in the ongoing SEF prevented the outer rainband from moving farther inward,helping the outer rainband to symmetrize into an outer eyewall.In the sensitivity experiment,no significant ULDI formed since the eyewall convection was weaker,and the eyewall anvil developed relatively lower,meaning the formation of a moat and thus an outer eyewall was less likely.This study suggests that a better-represented simulation of inner-eyewall convective structures and distribution of the solid-phase hydrometeors is important to the prediction of SEF.

关键词： tropical cyclone secondary eyewall formation upper-level descending inflow eyewall convection

Pollen analysis reveals the effects of uncovered interactions,pollen-carrying structures,and pollinator sex on the structure of wild bee-plant networks

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Insect Science 2024年第3期31卷 971-988页

作者： Clément Tourbez Carmelo Gómez-Martínez MiguelÁngel Gonzalez-Estévez Amparo Lazaro Mediterranean institute for Advanced Studies(UIB-CSIC) Global Change Research GroupEsporlesBalearic IslandsSpain Department of Biology Ecology AreaUniversity of the Balearic/slandsPalmaSpain

Pollination networks are increasingly used to model the complexity of interactions between pollinators and flowering plants in communities.Different methods exist to sample these interactions,with direct observations of plant-pollinator contacts in the field being by far the most common.Although the identification of pollen carried by pollinators allows uncovering interactions and increasing sample sizes,the methods used to build pollen-transport networks are variable and their effect on network structure remains unclear.To understand how interaction sampling influences the structure of networks,we analyzed the pollen found on wild bees from eight communities across Mallorca Island and investigated the differences in pollen loads between bee body parts(scopa vs.body)and sexes.We then assessed how these differences,as well as the uncovered interactions not detected in the field,influenced the structure of wild bee-plant networks.We identified a higher quantity and diversity of pollen in the scopa than in the rest of the female body,but these differences did not lead to differences in structure between plant-pollination(excluding scopa pollen)and bee-feeding interaction(including scopa pollen)networks.However,networks built with pollen data were richer in plant species and interactions and showed lower modularity and specialization(H2'),and higher nestedness than visitation networks based on field observations.Female interactions with plants were stronger compared to those of males,although not richer.Accordingly,females were more generalist(low d')and tended to be more central in interaction networks,indicating their more key role structuring pollination networks in comparison to males.Our study highlights the importance of palynological data to increase the resolution of networks,as well as to understand important ecological questions such as the differences between plant-pollination and bee-feeding interaction networks,and the role of sexes in pollination.

关键词： palynology pollen-transport networks pollination role of bee sexes sampling methodology visitation networks