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Enhancing Low-Frequency Microwave Absorption Through Structural Polarization Modulation of MXenes

Nano-Micro Letters 2024年第10期16卷 435-452页

作者： Bo Shan Yang Wang Xinyi Ji Yi Huang College of Light Industry Science and Engineering State Key Laboratory of Biobased Fiber Manufacturing TechnologyTianjin University of Science and TechnologyTianjin 300457People's Republic of China National Institute for Advanced Materials Tianjin Key Laboratory of Metal and Molecule Based Material ChemistryKey Laboratory of Functional Polymer MaterialsCollaborative Innovation Center of Chemical Science and Engineering(Tianjin)School of Materials Science and EngineeringNankai UniversityTianjin 300350People's Republic of China

Two-dimensional carbon-based materials have shown promising electromagnetic wave absorption capabilities in mid-and high-frequency ranges,but face challenges in low-frequency absorption due to limited control over polarization response mecha-nisms and ambiguous resonance *** this study,we pro-pose a novel approach to enhance absorption efficiency in aligned three-dimensional(3D)MXene/CNF(cellulose nanofibers)cavities by modifying polarization properties and manipulating resonance response in the 3D MXene *** controlled polarization mechanism results in a significant shift of the main absorption region from the X-band to the S-band,leading to a remarkable reflection loss value of-47.9 dB in the low-frequency ***,our findings revealed the importance of the oriented electromagnetic coupling in influencing electromagnetic response and microwave absorption *** present study inspired us to develop a generic strategy for low-frequency tuned absorption in the absence of magnetic element participation,while orientation-induced polarization and the derived magnetic resonance coupling are the key controlling factors of the method.

关键词： Hierarchical structure MXene Microwave absorption Low-frequency

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Efficient and Stable Photoassisted Lithium‑Ion Battery Enabled by Photocathode with Synergistically Boosted Carriers Dynamics

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Nano-Micro Letters 2025年第3期17卷 440-454页

作者： Zelin Ma Shiyao Wang Zhuangzhuang Ma Juan Li Luomeng Zhao Zhihuan Li Shiyuan Wang Yazhou Shuang Jiulong Wang Fang Wang Weiwei Xia Jie Jian Yibo He Junjie Wang Pengfei Guo Hongqiang Wang State Key Laboratory of Solidification Processing Center for Nano Energy MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene(NPU)Xi’an 710072People’s Republic of China State Key Laboratory of Solidification Processing School of Materials Science and Engineering DepartmentNorthwestern Polytechnical UniversityXi’an 710072People’s Republic of China State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072People’s Republic of China Research and Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063People’s Republic of China Key Laboratory of Applied Surface and Colloid Chemistry Shaanxi Key Laboratory for Advanced Energy DevicesShaanxi Engineering Lab for Advanced Energy TechnologySchool of Materials Science and EngineeringNational Ministry of EducationShaanxi Normal UniversityXi’an 710119People’s Republic of China

Efficient and stable photocathodes with versatility are of significance in photoassisted lithium-ion batteries(PLIBs),while there is always a request on fast carrier transport in electrochemical active *** work proposes a general approach of creating bulk heterojunction to boost the carrier mobility of photocathodes by simply laser assisted embedding of plasmonic *** employed in PLIBs,it was found effective for synchronously enhanced photocharge separation and transport in light charging ***,experimental photon spectroscopy,finite difference time domain method simulation and theoretical analyses demonstrate that the improved carrier dynamics are driven by the plasmonic-induced hot electron injection from metal to TiO_(2),as well as the enhanced conductivity in TiO2 matrix due to the formation of oxygen vacancies after Schottky *** from these merits,several benchmark values in performance of TiO2-based photocathode applied in PLIBs are set,including the capacity of 276 mAh g^(−1) at 0.2 A g^(−1) under illumination,photoconversion efficiency of 1.276%at 3 A g^(−1),less capacity and Columbic efficiency loss even through 200 *** results exemplify the potential of the bulk heterojunction strategy in developing highly efficient and stable photoassisted energy storage systems.

关键词： Photoassisted lithium-ion batteries Bulk heterojunction Carrier dynamics TiO2 nanofiber Plasmonic metal nanocrystals

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Pt–C interactions in carbon-supported Pt-based electrocatalysts

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Frontiers of Chemical Science and engineering 2023年第11期17卷 1677-1697页

作者： Yu-Xuan Xiao Jie Ying Hong-Wei Liu Xiao-Yu Yang School of Chemical Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing&Shenzhen Research Institute&Joint Laboratory for Marine Advanced Materials in Pilot National Laboratory for Marine Science and Technology(Qingdao) Wuhan University of TechnologyWuhan 430070China

Carbon-supported Pt-based materials are highly promising *** carbon support plays an important role in the Pt-based catalysts by remarkably influencing the growth,particle size,morphology,dispersion,electronic structure,physiochemical property and function of *** review summarizes recent progress made in the development of carbon-supported Pt-based catalysts,with special emphasis being given to how activity and stability enhancements are related to Pt–C interactions in various carbon supports,including porous carbon,heteroatom doped carbon,carbon-based binary support,and their corresponding electrocatalytic ***,the current challenges and future prospects in the development of carbon-supported Pt-based catalysts are discussed.

关键词： Pt-C interactions Pt-based materials carbon support electrocatalysis

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Phase field modeling of grain stability of nanocrystalline alloys by explicitly incorporating mismatch strain

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Rare Metals 2024年第7期43卷 3370-3382页

作者： Min Zhou Hong-Hui Wu Yuan Wu Hui Wang Xiong-Jun Liu Sui-He Jiang Xiao-Bin Zhang Zhao-Ping Lu Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083Cnina Institute for Carbon Neutrality University of Science and TechnologyBeijing 100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

Ab st ra ct Nanocrystalline materials exhibit unique properties due to their extremely high grain boundary(GB) ***,this high-density characteristic induces grain coarsening at elevated temperatures,thereby limiting the widespread application of nanocrystalline *** experimental observations revealed that GB segregation and second-phase pinning effectively hinder GB migration,thereby improving the stability of nanocry stalline *** this study,a mouified phase-field model that integrates mismatch strain,solute segregation and precipitation was developed to evaluate the influence of lattice misfit on the thermal stability of nanocrystalline *** simulation results indicated that introducing a suitable mismatch strain can effectively enhance the microstructural stability of nanocrystalline *** synergizing precipitation with an appropriate lattice misfit,the formation of second-phase particles in the bulk grains can be suppressed,thereby facilitating solute segregation/precipitation at the *** concentrated solute segregation and precipitation at the GBs effectively hinders grain migration,thereby preventing grain *** findings provide a new perspective on the design and regulation of nanocrystalline alloys with enhanced thermal stability.

关键词： Phase field model Mismatch strain Second-phase precipitation Grain boundary segregation Nanocrystalline alloys

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A Preliminary Look at the Unity of Frequency Support for Grid-Following and Grid-Forming Wind Turbines

A Preliminary Look at the Unity of Frequency Support for Gri...

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2024 IEEE China International Youth Conference on Electrical engineering, CIYCEE 2024

作者： Zhou, Hongyu Yao, Wei Zong, Qihang Wen, Jinyu Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan430074 China

ISBN: (纸本)9798331530174

Grid-connected wind turbines for frequency support of the grid is conducive to improving the grid frequency security level. Grid-following (GFL) converters and gridforming (GFM) converters are two important types of equipment to support renewable energy integration into the grid. Both GFM and GFL have a variety of different control strategies when performing frequency support. Clarifying the relationship be-tween different strategies of GFM and GFL when performing frequency support will provide guidance for renewable energy frequency support. In this paper, four levels of frequency support uniformity are first established at the generation unit level. (1) The governor and damping branch of the virtual synchronous generator (VSG) control based GFM converter are unified. (2) The VSG based GFM and the droop based GFM are unified. (3) Integrated inertial control based GFL and droop based GFL are unified. Finally, the theoretical analysis is synthetically verified by MATLAB/Simulink simulation platform. © 2024 IEEE.

关键词： MATLAB

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Cu-Cu low-temperature diffusion bonding by spark plasma sintering:Void closure mechanism and mechanical properties

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Journal of Materials Science & technology 2023年第8期139卷 210-223页

作者： Wendi Li Yuxin Liang Yang Bai Tiesong Lin Bangsheng Li Jicai Feng School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China

In this study,combining the single point diamond turning(SPDT)and spark plasma sintering(SPS),we achieved high-strength diffusion bonding of copper at an ultra-low temperature of 202℃(0.35 T_(m),T_(m):absolute temperature of the melting point).Additionally,the closure mechanism of interfacial micro-and nano-voids during the Cu-Cu SPS diffusion bonding is systematically revealed for the first *** micro-voids,the pulsed current is found to induce additional diffusion flux and plastic deformation,thereby facilitating the void *** dynamics(MD)simulation revealed that at the atomic scale,high-energy Cu atoms induced by the pulsed current can significantly promote the diffusion of low-energy atoms in their vicinity and accelerate the void *** study also proposes a novel“evaporation-deposition”nano-void closure mechanism for the previously unstudied nano-void closure *** results show that the synergistic effect of the pulsed current and nanoscale surface rough-ness can significantly improve joint *** a low temperature of 405℃(0.5 T_(m)),on combining the computerized numerical control(CNC)turning and SPS diffusion bonding,the joint strength can reach 212 MPa,while that for the joint obtained by traditional hot pressing diffusion bonding at the same tem-perature is only 47 *** obtained an ultra-high joint strength of 271 MPa using the combined process of SPDT and SPS diffusion bonding at an ultra-low temperature of 202℃(0.35 T_(m)),which is approximately 600℃ lower than the traditional diffusion bonding process temperature of 800℃(0.79 T_(m)).To sum up,this study provides a novel method and theoretical support for realizing low-temperature high-strength diffusion bonding.

关键词： Spark plasma sintering Diffusion bonding Void closure mechanism Mechanical property Molecular dynamics

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Design of a submerged entry nozzle for optimizing continuous casting of stainless steel slab

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Journal of Iron and Steel Research International 2023年第11期30卷 2229-2241页

作者： Jia-chen Pang Guo-yu Qian Sheng Pang Wen-hui Ma Guo-guang Cheng School of Metallurgy and Energy Engineering Kunming University of Science and TechnologyKunming650093YunnanChina CAS Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing100190China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China

To solve slag entrapment and casting slab defects in the process of stainless steel continuous casting,submerged entry nozzle(SEN)for slab casters operating at casting speed of 1 m/min was developed based on 3D numerical simulation and water modeling experiments by controlling the outlet shape and angle of original SEN with oval and 15°angle outlet under current industrial *** simulations of fluid velocity at outlets with different shapes and angles of SENs have been carried *** results showed that oval outlet with 5°and 15°angle led to asymmetric rotating flow pattern at outlet,as well as square outlet with 15°angle,but symmetric flow pattern formed at square outlet with 5°*** effect of these SENs on meniscus stability,flow field and slag entrapment behavior of stainless steel slab casting mold was further studied by water modeling *** results showed that difficult floating fine droplets formed when the angle of outlet was 15°under the dual effect of vortex convection and shear force due to the strong swirling flow from outlet and rotating flow of ***,outlet with 5°angle could lead to the formation of larger slag droplets,while the oval outlet with 5°angle could result in the scour to the mold ***,the square outlet with 5°angle was a relatively ideal solution for the submerged entry nozzle from the aspects of the stability of the mold and the slag entrapment *** the design of a new SEN according to the experimental result,the solidification structure of continuous casting slab was obviously improved by industrial test.

关键词： Stainless steel Continuous casting Submerged entry nozzle Water modeling Slag entrapment

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A room-temperature magnetic semiconductor from a Co-Fe-Nb-B metallic glass

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Science China(Physics,Mechanics & Astronomy) 2023年第4期66卷 94-99页

作者： Yu-Zhang Jiao Dmitry VLouzguine-Luzgin Ke-Fu Yao Zheng-Jun Zhang Na Chen Laboratory for Advanced Materials Processing Technology(MOE) State Key Laboratory of New Ceramics and Fine ProcessingSchool of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials(MOE) Schoolof Materials Science and EngineeringTsinghua UniversityBeijing 100084China Advanced Institute for Materials Research(WPI-AIMR) Tohoku UniversitySendai 980-8577Japan Mathematics for Advanced Materials-OIL National Institute of Advanced Industrial Science and Technology(AIST)Sendai 980-8577Japan

Magnetic semiconductors with Curie temperatures higher than room temperature show potential for developing spintronic devices with combined data processing and storage functions for next-generation computing *** this study,we present an n-type Co_(19.8)Fe_(8.6)Nb_(4.3)B_(6.0)O_(61.3) magnetic semiconductor with a high Curie temperature of~559 *** magnetic semiconductor has a room-temperature resistivity of~2.10×10^(4)Ωcm and a saturation magnetization of~76 emu/cm^(3).The n-type Co_(19.8)Fe_(8.6)Nb_(4.3)B_(6.0)O_(61.3)magnetic semiconductor was deposited on p-type silicon to form a heterojunction,exhibiting a rectifying *** results provide the design principles for discovering high Curie temperature magnetic semiconductors with determined conduction types,which would play an essential role in realizing nonvolatile spin-based transistors that break free from the confines of currently established Si-based information technology.

关键词： magnetic semiconductor ferromagnetic metallic glass high Curie temperature

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Analytical analysis of hollow CORC cable under thermo-mechanical loads

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Superconductivity 2023年第1期5卷 26-39页

作者： Xianhao Li Yuejin Tang Ying Xu Li Ren State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan 430074China School of Electrical and Electronic Engineering Huazhong University of Science and TechnologyWuhan 430074China

According to engineering experience,the axial shrinkage caused by the refrigerant seriously endangers the performance of long‐distance conductor on round core(CORC)*** outage maintenance of high‐temperature superconducting(HTS)cables is inevitable,providing appropriate compensation for cyclic temperature is one of the key technologies in the actual application of power ***,this paper presents an analytical solution for hollow CORC cables under thermo‐mechanical ***,regarded as an axisymmetric composite structure,the radial temperature distribution of CORC cable under Dirichlet boundary or mixed boundary conditions was ***,assuming cable ends were axially fixed,a recursive method without variables is used to evaluate its displacement,strains,and ***,an algebraic method with axial strain as a variable is developed to analyze the mechanical behavior of the CORC cable more ***,concluded from the above derivation,a matrix equation is constructed based on continuity equations and boundary conditions,which applies to isotropic and orthotropic materials with *** results show that the analytical solution agrees with finite element method(FEM)*** to the trial results of a 360 m CORC cable,the calculation error of axial shrinkage is within 1.63 cm,and the relative error is within 6.1%.In addition,the recursive method is the fastest to calculate axial strain,while the matrix method has a significant efficiency advantage in calculating the stresses and strains of each layer.

关键词： CORC cable Analytical solution Thermo‐mechanical loads Axial shrinkage Recursive method Algebraic method

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Supplementary Control for Mitigation of Successive Commutation Failures Considering the Influence of PLL Dynamics in LCC-HVDC Systems

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CSEE Journal of Power and Energy Systems 2022年第3期8卷 872-879页

作者： Jun Lu Xiaoming Yuan Meiqing Zhang Jiabing Hu State Key Laboratory of Advanced Electromagnetic Engineering and Technology and the School of Electrical and Electronic Engineering Huazhong University of Science and TechnologyWuhan430074China

Line commutated converter based high voltage direct current(LCC-HVDC)links are widely employed for long distance bulk power transmission and asynchronous alternating current(AC)grid ***,LCC-HVDC systems often suffer from commutation failures when AC voltage is distorted,oscillating or reduced by AC faults,which leads to overheating of converter valves and interruptions in transmitted *** of which can have an adverse impact on the safety and stability of the entire power *** paper proposes a supplementary control for mitigation of successive commutation failures on the basis of analyzing the influence of phase-locked loop(PLL)dynamics on the commutation *** analyzing the impact of PLL dynamics on the actual leading angle,it is found that changes in the AC voltage phase remarkably influence ***,the error between the AC voltage phase and PLL’s output angle is added to the output of the extinction angle or DC voltage control to mitigate the successive commutation failures of LCC-HVDC *** conducted on the CIGRE benchmark model in PSCAD/EMTDC validate the performance of the supplementary control,which effectively mitigates successive commutation failures.

关键词： Commutation failure dynamics LCC-HVDC mitigation PLL supplementary control

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