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Large focal length planar focusing of Dyakonov polaritons in hyperbolic metamaterial

Progress in Natural science:materials International 2024年第4期34卷 632-636页

作者： Xiaoyu Xiong Yihang Fan Weipeng Wang Yongzheng Wen Zhengjun Zhang Jingbo Sun Ji Zhou State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Key Laboratory of Advanced Materials (MOE) School of Materials Science and Engineering Tsinghua University

Achieving subwavelength optical focusing is of great importance in nanophotonics. However, achieving focusing with both a small focal spot size and a large focal length remains elusive so far. Here, a large focal length planar focusing device is presented, utilizing highly oriented Dyakonov polaritons in hyperbolic metamaterial with periodic silver rings as the excitation source. Experimental results show that by controlling the size of the excitation sources, the focal length can reach 6λ0（where λ0is the illumination wavelength）, and the focal spot size can be reduced to λ0/10. This method provides new prospects for planar polariton optical applications.

关键词： Subwavelength optical focusing Dyakonov polaritons In-plane hyperbolic metamaterials Near-field optics

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Dual heterogeneous structure enabled ultrahigh strength and ductility across a broad temperature range in CrCoNi-based medium-entropy alloy

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材料科学技术（英文版） 2025年第4期207卷 46-59页

作者： Kang Tu Bo Li Zonglin Li Kaisheng Ming Shijian Zheng Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology School of Materials Science and EngineeringHebei University of TechnologyTianjin 300130China

Developing alloys with exceptional strength-ductility combinations across a broad temperature range is crucial for advanced structural *** emerging face-centered cubic medium-entropy alloys(MEAs)demonstrate outstanding mechanical properties at both ambient and cryogenic *** are anticipated to extend their applicability to elevated temperatures,owing to their inherent ad-vantages in leveraging multiple strengthening and deformation ***,a dual heterostructure,comprising of heterogeneous grain structure with heterogeneous distribution of the micro-scale Nb-rich Laves phases,is introduced in a CrCoNi-based MEA through thermo-mechanical ***,a high-density nano-coherent γ'phase is introduced within the grains through isothermal aging *** superior thermal stability of the heterogeneously distributed precipitates enables the dual heterostructure to persist at temperatures up to 1073 K,allowing the MEA to maintain excellent mechan-ical properties across a wide temperature *** yield strength of the dual-heterogeneous-structured MEA reaches up to 1.2 GPa,1.1 GPa,0.8 GPa,and 0.6 GPa,coupled with total elongation values of 28.6％,28.4％,12.6％,and 6.1％at 93 K,298 K,873 K,and 1073 K,*** high yield strength primar-ily stems from precipitation strengthening and hetero-deformation-induced *** high flow stress and low stacking fault energy of the dual-heterogeneous-structured MEA promote the formation of high-density stacking faults and nanotwins during deformation from 93 K to 1073 K,and their den-sity increase with decreasing deformation *** greatly contributes to the enhanced strain-hardening capability and ductility across a wide temperature *** study offers a practical solu-tion for designing dual-heterogeneous-structured MEAs with both high yield strength and large ductility across a wide temperature range.

关键词： Medium-entropy alloy Dual heterogeneous structure Strength-ductility synergy Cryogenic temperatures Elevated temperatures

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Effects of longitudinal magnetic field on primary dendrite spacing and segregation of directionally solidified single crystal superalloy

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Progress in Natural science:materials International 2024年第1期34卷 26-36页

作者： Congjiang Zhang Yilin Zhou Chen Shen Weili Ren Xiaotan Yuan Biao Ding Haibiao Lu Zuosheng Lei Yunbo Zhong Ang Zhang State Key Laboratory of Advanced Special Steel College of Materials Science and Engineering Shanghai University National Engineering Research Center for Magnesium Alloys Natural Key Laboratory of Advanced Casting Technologies College of Materials Science and EngineeringChongqing University

The primary dendrite spacing(PDS) and segregation of directionally solidified single crystal(SC) superalloy under the longitudinal magnetic field(LMF) were investigated based on the analysis of the whole cross-sectional microstructure at different solidification distances. The results show that the PDS under the LMF remains basically unchanged at different solidification distances, and it is greater than that under no LMF. With the increase of magnetic field intensity, the PDS increases and the macrosegregation decreases. The increasing PDS and reducing segregation under the LMF can be attributed to the increase of solute boundary layer, which expands the non-equilibrium freezing temperature range and brings the effective partition coefficient closer to 1. The increase of the solute enrichment layer thickness could be caused by the downward secondary circulation generated by the thermoelectric magnetic convection(TEMC) near the interface, which drives the migration of solutes towards the interdendritic region. This work not only clarifies the mechanism of LMF controlling PDS and reducing segregation by TEMC, but also provides theoretical guidance for producing high-quality SC superalloys using magnetic fields.

关键词： Primary dendrite spacing Segregation Single crystal superalloy Directional solidification Magnetic field Thermoelectric magnetic convection

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Li Alloys in All Solid-State Lithium Batteries:A Review of Fundamentals and Applications

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Electrochemical Energy Reviews 2024年第1期7卷 586-623页

作者： Jingru Li Han Su Yu Liu Yu Zhong Xiuli Wang Jiangping Tu State Key Laboratory of Silicon and Advanced Semiconductor Materials Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang ProvinceSchool of Materials Science and EngineeringZhejiang UniversityHangzhou 310027ZhejiangChina

All solid-state lithium batteries(ASSLBs)overcome the safety concerns associated with traditional lithium-ion batteries and ensure the safe utilization of high-energy-density electrodes,particularly Li metal anodes with ultrahigh specific ***,the practical implementation of ASSLBs is limited by the instability of the interface between the anode and solid-state electrolyte(SSE).To mitigate this,considerable research has been dedicated to achieving enhanced stability at the anode/SSE *** the current strategies for enhancing interface performance,the concept of Li-alloy materials is extensively used and well functionalized in various scenarios,including Li alloys as anodes,Li-alloy interlayers and Li alloys in the *** the notable achievements of Li-alloy materials in ASSLBs,the functionality,practicality and working mechanism of Li-alloys have not been fully *** review commences by providing an exhaustive and in-depth examination of the fundamental kinetics,thermodynamics,and mechanics,highlighting Li-alloy ***,through a systematic interconnection of material properties and their practical applications,we undertake a comprehensive analysis of the operative principles governing Li *** analytical approach allows a thorough evaluation of the viability and utility of Li alloys within the context of ***,this review concludes by succinctly summarizing the future prospects and inherent potential of Li-alloy materials for further advancing the field of ASSLBs.

关键词： Li alloys Anode All-solid-state lithium batteries Physicochemical properties Applications

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Rheological Behaviors of Polymers with Nanoparticles Tethered at Each End

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Chinese Journal of Polymer science 2024年第3期42卷 400-406,I0009页

作者： Song-Qi Zhang Wen-Qing Wang Jia-Ping Lin Li-Quan Wang Shanghai Key Laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials of Ministry of EducationSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China

The polymer with nanoparticles tethered at each end is a unique model for unraveling the effect of chain ends on the polymer dynamics. We investigated the rheological behavior of this kind of polymer by using nonequilibrium molecular dynamics simulation. The effect of polymer lengths and nanoparticle radii on the complex moduli and viscosity was examined. The dependence of complex moduli on the frequency becomes less pronounced as the polymer is short or the nanoparticle is large. The shear thinning behavior was revealed for these systems, and the scaling exponent of complex viscosity with respect to the frequency was found to change from-1/2 to-3/4 as the polymer shortens or the nanoparticle enlarges. The rheological behavior was further explained by analyzing the mean square distance of nanoparticles. The simulation results were compared with the existing experimental finding, showing an agreement. The work provides information for understanding the chain end effect on polymer rheology.

关键词： Polymer rheology Modulus Viscosity Molecular dynamics

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Obtaining extremely low coercivity of high Bs FeCoBSiCPCu nanocrystalline alloys through modulation of magnetic anisotropy

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材料科学技术（英文版） 2025年第4期207卷 105-112页

作者： Mingjuan Cai Zhijun Guo Lei Li Xingyu Zheng Xiaoxuan Yang Qianqian Liu Gaopeng Zou Baolong Shen School of Materials Science and Engineering Jiangsu Key Laboratory for Advanced Metallic Materials Southeast UniversityNanjing 211189PR China

Longitudinal magnetic field annealing is utilized for modifying the magnetic anisotropy and enhancing the magnetic softness of Fe75Co8(B10Si3C3P1)1-x/17Cux(x=0.5,0.75,1,1.25)nanocrystalline *** of the magnetic field-annealed nanocrystalline alloys with Cu content more than 0.5 at.％exhibit signifi-cantly improved soft-magnetic properties,including high saturation magnetic flux density up to 1.87 T,effective permeability of 13,000-16,000 under the condition of 1 A/m and 1 kHz,coercivity as low as 1.6 A/m,and core loss of 0.11-0.45 W/kg under the condition of 1.0 T and 50 *** application of a magnetic field promotes the nucleation and inhibits the growth of grains,leading to an increase in the number density of nanocrystals and the crystalline volume fraction,and a reduction in the grain *** magnetic field annealing reduces the effective magneto-crystalline anisotropy energy to 2-4 J/m3,and induces longitudinal magnetic anisotropy with anisotropy energy density of 400-900 J/m3 which shows dependence on the crystalline volume *** field-induced magnetic anisotropy dominates over the random local magnetic anisotropies,and results in the formation of regular magnetic domains aligned longitudinally,pinning-free domain wall displacement,and thus enhanced soft-magnetic proper-ties.

关键词： Nanocrystalline alloy Magnetic anisotropy Magnetic field annealing Soft-magnetic property Microstructure

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Highly efficient and photothermally stable CDs@ZIF-8 for laser illumination

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Chinese Chemical Letters 2024年第10期35卷 273-277页

作者： Zhi Wang Lingpeng Yan Yelin Hao Jingxia Zheng Yongzhen Yang Xuguang Liu Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China

Carbon dots(CDs),as a solid-state phosphor,have great potential for application in a new solid-state lighting device—laser diode(LD).For high efficiency LD devices,both high photoluminescence quantum yield(PLQY)and high photothermal stability of CDs are ***,yellow CDs@ZIF-8 composites with high structural stability were prepared by encapsulating CDs in zeolitic imidazolate framework-8(ZIF-8)through electrostatic adsorption between CDs and ZIF-8,in which CDs with amino groups on the surface were used as luminescent feeders and ZIF-8 was used as a protective layer *** asprepared CDs@ZIF-8 not only possess a high PLQY of up to 81.17%,but also maintain a high fluorescence intensity of 100%and 80%under long-term illumination(60 min)and high temperature(478 K),*** hydrogen bonding between CDs and ZIF-8 in the encapsulated structure can enhance the degree of electron cloud delocalization,which can improve the PLQY of CDs@***,CDs@ZIF-8has high photothermal stability due to the binding effect of ZIF-8 on CDs and high thermal stability of *** white LD device,fabricated from CDs@ZIF-8 as a phosphor in combination with 450 nm blue LD,has a color coordinate of(0.37,0.33),a color temperature of 3762 K,and a high color rendering index of *** study provides a new strategy for the construction of solid-state phosphors with high PLQY and high photothermal performance.

关键词： Carbon dots Metal-organic frameworks High photothermal stability High photoluminescence quantum yield Laser illumination

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In situ construction of Cu(Ⅰ)-Cu(Ⅱ) pairs for efficient electrocatalytic nitrate reduction reaction to ammonia

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Journal of Energy Chemistry 2025年第1期100卷 106-113页

作者： Muyun Zheng Yuchi Wan Leping Yang Shen Ao Wangyang Fu Zhengjun Zhang Zheng-Hong Huang Tao Ling Feiyu Kang Ruitao Lv State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Institute of New Energy Materials and Engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108FujianChina Key Laboratory of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education Tianjin Key Laboratory of Composite and Functional MaterialsSchool of Materials Science and EngineeringTianjin UniversityTianjin 300072China

Electrocatalytic nitrate reduction reaction (NO_(3)-RR) to ammonia under ambient conditions is expected to be a green process for ammonia synthesis and alleviate water pollution *** report a CuO nanoparticles incorporated on nitrogen-doped porous carbon (CuO@NC) catalyst for NO_(3)-*** of Cu(Ⅱ) is reduced to Cu(Ⅰ) during the NO_(3)-RR process to construct Cu(Ⅰ)-Cu(Ⅱ) pairs,confirmed by in situ X-ray photoelectron spectroscopy (XPS) and Raman *** functional theory (DFT) calculations indicated that the formation of Cu(Ⅰ) could provide a reaction path with smaller energy barrier for NO_(3)-RR,while Cu(Ⅱ) effectively suppressed the competition of hydrogen evolution reaction (HER).As a result,CuO@NC catalyst achieved a Faradaic efficiency of 84.2% at -0.49 V versus reversible hydrogen electrode (RHE),and a NH_(3)yield rate of 17.2 mg h^(-1)mg^(-1)*** -0.79 V ***,higher than the HaberBosch process (<3.4 g h^(-1)g^(-1)cat.).This work may open a new avenue for effective NO_(3)-RR by modulating oxidation states.

关键词： Ammonia synthesis Cu oxidation state Electrochemistry Nitrate reduction In situ XPS

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Intelligent casting:Empowering the future foundry industry

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China Foundry 2024年第5期21卷 409-426页

作者： Jin-wu Kang Bao-lin Liu Tao Jing Hou-fa Shen School of Materials Science and Engineering Key Laboratory for Advanced Materials Processing TechnologyTsinghua UniversityBeijing 100084China

Emerging technological advances are reshaping the casting sector in latest *** technology is evolving towards intelligent casting paradigm that involves automation,greenization and intelligentization,which attracts more and more attention from the academic and industry *** this paper,the main features of casting technology were briefly summarized and forecasted,and the recent developments of key technologies and the innovative efforts made in promoting intelligent casting process were ***,the technical visions of intelligent casting process were also put *** key technologies for intelligent casting process comprise 3D printing technologies,intelligent mold technologies and intelligent process control *** future,the intelligent mold that derived from mold with sensors,control devices and actuators will probably incorporate the Internet of Things,online inspection,embedded simulation,decision-making and control system,and other technologies to form intelligent cyber-physical casting system,which may pave the way to realize intelligent *** is promising that the intelligent casting process will eventually achieve the goal of real-time process optimization and full-scale control,with the defects,microstructure,performance,and service life of the fabricated castings can be accurately predicted and tailored.

关键词： intelligent casting 3D printing intelligent mold process control cyber-physical casting system embedded simulation

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A high-sensitive and self-selective humanoid mechanoreceptor for spatiotemporal tactile stimuli cognition

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Nano Research 2024年第5期17卷 4400-4409页

作者： Shuxin Bi Xuan Zhao Fangfang Gao Xiaochen Xun Bin Zhao Liangxu Xu Tian Ouyang Qingliang Liao Yue Zhang Academy for Advanced Interdisciplinary Science and Technology Beijing Advanced Innovation Center for Materials Genome EngineeringUniversity of Science and Technology(Beijing)Beijing 100083China Key Laboratory of Advanced Materials and Devices for Post-Moore Chips Ministry of EducationBeijing Key Laboratory for Advanced Energy Materials and TechnologiesSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China

The cognition of spatiotemporal tactile stimuli,including fine spatial stimuli and static/dynamic temporal stimuli,is paramount for intelligent robots to feel their surroundings and complete manipulation ***,current tactile sensors have restrictions on simultaneously demonstrating high sensitivity and performing selective responses to static/dynamic stimuli,making it a challenge to effectively cognize spatiotemporal tactile ***,we report a high-sensitive and self-selective humanoid mechanoreceptor(HMR)that can precisely respond to spatiotemporal tactile *** HMR with PDMS/chitosan@CNTs(PDMS:polydimethylsiloxane;CNT:carbon nanotube)graded microstructures and polyurethane hierarchical porous spacer exhibits high sensitivity of 3790.8 kPa^(-1).The HMR demonstrates self-selective responses to static and dynamic stimuli with mono signal through the hybrid of piezoresistive and triboelectric ***,it can respond to spatiotemporal tactile stimuli and generate distinguishable and multi-type characteristic *** the assistance of the convolutional neural network,multiple target objects can be easily identified with a high accuracy of 99.1%.This work shows great potential in object precise identification and dexterous manipulation,which is the basis of intelligent robots and natural human-machine interactions.

关键词： mechanoreceptors self-selective high-sensitive spatiotemporal tactile stimuli cognition sensors

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