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Grain growth behavior and properties of high-entropy pseudobrookite(Mg,Co,Ni,Zn)Ti_(2)O_(5) ceramics

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Journal of Advanced Ceramics 2024年第6期13卷 757-768页

作者： Xiaohui Ma Jinyu Wu Lingyi Meng Jinfeng Zhang Heng Chen Liwen Yan Anran Guo Jiachen Liu Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education School of Materials Science and EngineeringTianjin UniversityTianjin 300072China Xiamen Key Laboratory of Rare Earth photoelectric Functional Materials Xiamen Institute of Rare Earth MaterialsHaixi InstitutesChinese Academy of SciencesXiamen 361021China

It is well known that the grain size of high-entropy ceramics is quite small owing to the sluggish diffusion effect. However, abnormal grain growth often occurs in high-entropy pseudobrookite ceramics, ultimately resulting in the formation of many abnormally grown grains with a grain size as large as 50 μm. To study this phenomenon, the grain growth behavior of high-entropy pseudobrookite ceramics was systematically investigated in this paper. The results demonstrate that the starting material powders first react with each other to form a high-entropy intermediate phase and calcined TiO_(2) powders (TiO_(2)-1100 ℃), and then as the sintering temperature increases, the formed high-entropy intermediate phase further reacts with TiO_(2)-1100 ℃ to form high-entropy pseudobrookite ceramics. Thus, in this system, in addition to the sluggish diffusion effect, the grain sizes of the high-entropy intermediate phase and TiO_(2)-1100 ℃ also affect the morphology of high-entropy pseudobrookite. Compared to nanosized TiO_(2), micron-sized TiO_(2) has a lower sintering activity. Therefore, the high-entropy intermediate phases (Mg,Co,Ni,Zn)TiO_(3) and TiO_(2)-1100 ℃ prepared with micron-sized starting materials exhibit lower grain sizes, finally resulting in the formation of high-entropy (Mg,Co,Ni,Zn)Ti_(2)O_(5) with small grain sizes. Moreover, nano-indentation and thermal conductivity tests were carried out on high-entropy (Mg,Co,Ni,Zn)Ti_(2)O_(5) with different morphologies. The results show that the hardness of high-entropy (Mg,Co,Ni,Zn)Ti_(2)O_(5) increases from 6.05 to 9.95 GPa as the grain size increases, whereas the thermal conductivity decreases from 2.091±0.006 to 1.583±0.006 W·m^(−1)·K^(−1). All these results indicate that high-entropy (Mg,Co,Ni,Zn)Ti_(2)O_(5) with a small grain size is a potential material for thermal protection.

关键词： grain size sluggish diffusion effect two-step solid phase process high-entropy intermediate phase high-entropy pseudobrookite ceramic

Second-harmonic generation in periodic fork-shaped χ^((2)) gratings at oblique incidence

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Chinese Optics Letters 2024年第4期22卷 101-105页

作者：盛艳刘山胡效康陈鑫徐天翔赵如薇 Wieslaw Kroli kowski Laboratory of Infrared Materials and Devices Research Institute of Advanced TechnologiesNingbo UniversityNingbo 315211China engineering Research Center for Advanced Infrared photoelectric Materials and Devices of Zhejiang Province Ningbo UniversityNingbo 315211China Department of Quantum Science and Technology Research School of PhysicsAustralian National UniversityCanberra ACT 2601Australia school of Physics and Optoelectronics engineering Xidian UniversityXi’an 710071China

Three-dimensional(3D) nonlinear photonic crystals have received intensive interest as an ideal platform to study nonlinear wave interactions and explore their applications. Periodic fork-shaped gratings are extremely important in this context because they are capable of generating second-harmonic vortex beams from a fundamental Gaussian wave, which has versatile applications in optical trapping and materials engineering. However, previous studies mainly focused on the normal incidence of the fundamental Gaussian beam, resulting in symmetric emissions of the second-harmonic vortices. Here we present an experimental study on second-harmonic vortex generation in periodic fork-shaped gratings at oblique incidence, in comparison with the case of normal incidence. More quasi-phase-matching resonant wavelengths have been observed at oblique incidence, and the second-harmonic emissions become asymmetric against the incident *** results agree well with theoretic explanations. The oblique incidence of the fundamental wave is also used for the generation of second-harmonic Bessel beams with uniform azimuthal intensity distributions. Our study is important for a deeper understanding of nonlinear interactions in a 3D periodic medium. It also paves the way toward achieving highquality structured beams at new frequencies, which is important for manipulation of the orbital angular momentum of light.

关键词： second-harmonic generation nonlinear photonic crystal periodically poled ferroelectric crystal quasi-phase matching nonlinear wavefront shaping

A flexible ultra-broadband multi-layered absorber working at 2 GHz-40 GHz printed by resistive ink

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Chinese Physics B 2024年第2期33卷 329-333页

作者：汪涛闫玉伦陈巩华李迎胡俊毛剑波 school of Microelectronics Hefei University of TechnologyHefei 230601China Special Display and Imaging Technology Innovation Center of Anhui Province Academy of Photoelectric TechnologyHefei University of TechnologyHefei 230027China

A flexible extra broadband metamaterial absorber(MMA)stacked with five layers working at 2 GHz–40 GHz is *** layer is composed of polyvinyl chloride(PVC),polyimide(PI),and a frequency selective surface(FSS),which is printed on PI using conductive *** investigate this absorber,both one-dimensional analogous circuit analysis and three-dimensional full-wave simulation based on a physical model are *** crucial electromagnetic properties,such as absorption,effective impedance,complex permittivity and permeability,electric current distribution and magnetic field distribution at resonant peak points,are studied in *** shows that the working frequency of this absorber covers entire S,C,X,Ku,K and Ka bands with a minimum thickness of 0.098λ_(max)(λ_(max) is the maximum wavelength in the absorption band),and the fractional bandwidth(FBW)reaches 181.1%.Moreover,the reflection coefficient is less than-10 dB at 1.998 GHz–40.056 GHz at normal incidence,and the absorptivity of the plane wave is greater than 80%when the incident angle is smaller than 50°.Furthermore,the proposed absorber is experimentally validated,and the experimental results show good agreement with the simulation results,which demonstrates the potential applicability of this absorber at 2 GHz–40 GHz.

关键词： extra broadband physical model flexible metamaterial absorber multi-layer frequency selective surface

A high-performance electrocatalyst for oxygen reduction derived from copolymer-anchored polyoxometalates

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Nano Research 2024年第6期17卷 5197-5205页

作者： Yue Du Wenxue Chen Zhiyi Zhong Zhixian Shi Yulin Zhang Xuanning Chen Yisi Liu Dongbin Xiong Lina Zhou Zhenhui Liu Mingbo Zheng Hubei Key Laboratory of photoelectric Materials and Devices&College of Material Science and engineering Hubei Normal UniversityHuangshi 435002China College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The development and synthesis of cathode electrocatalysts with high activity and durable stability for metal-air batteries is an important challenge in the area of ***,we introduce a novel in-situ nitriding and phosphating strategy for producing W_(3)N_(4)and WP from phosphotungstic acid(HPW)-polyaniline-phytic acid-Fe3+organic-inorganic hybrid *** final material has a three-dimensional porous framework with W_(3)N_(4)-WP heterostructures embedded in the carbon matrix(W_(3)N_(4)-WP@NPC).As-made materials exhibit exceptional electrocatalytic performance for the oxygen reduction reaction(ORR),with a diffusion-limiting current density of 6.9 mA·cm^(−2)and a half-wave potential of 0.82 *** a Zn-air primary cathode,the W_(3)N_(4)-WP@NPC assembled battery can provide a relatively high peak power density(194.2 mW·cm^(−2)).As a Zn-air secondary air-cathode,it has great cycling stability over 500 *** work provides a simple and efficient method for rationally designing high-performance air cathodes from copolymer-anchored polyoxometalates.

关键词： W_(3)N_(4)-WP heterojunctions copolymer-anchored polyoxometalates oxygen reduction reaction Zn-air battery

Side-Chain-Type Polyimide-Cu Complexes with Suppressed Activation Energy of Relaxation for Advanced High-Temperature Capacitor

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Chinese Journal of Polymer Science 2024年第8期42卷 1038-1048页

作者： Bai-Yang Zhou Ze-Tong Ma Shi-Long Zhong Zhen-Jie Huang Qi Guo Deng-Chong Feng Zhong-Ke Yuan Shao-Lin Lu Yu-Zhao Yang Cheng Wang Ding-Shan Yu Xu-Dong Chen Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education Guangdong Engineering Technology Research Centre for High Performance Organic and Polymer Photoelectric Functional FilmsSchool of ChemistrySun Yat-sen UniversityGuangzhou 510275China school of Chemical engineering and Light Industry Guangdong University of TechnologyGuangzhou 510006China Guangdong Provincial Laboratory of Chemistry and Fine Chemical Industry Jieyang Centre Jieyang 515200China Chemistry and Chemical engineering Guangdong Laboratory Shantou 515031China

The burgeoning growth of the new energy vehicles and aviation industry has escalated the need for energy storage capacitors capable of stable operation in harsh *** advent of metal-polyimide complexes has illuminated a novel approach for preparing tem perature-resistant ***,the general application of these metal-polyimide com plexes is impeded by the high dielectric loss and low breakdown strength,consequences of main-chain coordination and excessive metal ions ***,our study proposes a novel polyimideCu complex material(POP-Cu)predicated on side-chain-type pyridine-Cu coordination,utilizing the structural backbone PMDA-ODA of mature commercial PI(Kapton)with reliable *** to the high degree of freedom afforded by the side chain with suppressed relaxation activation energy and the long-range electron delocalization formed by d-πcoordination,the dielectric constant of this material containing merely 2.7 mol%Cu increases from 3.25(POPI)to 5.58,while maintaining a remarkably low dielectric loss of ***,this material exhibits a substantial DC breakdown strength of 436.2 MV·m^(-1)and a high energy density of 5.42 J·cm^(-3),coupled with superior mechanical and thermal *** at 150℃,it retains over 90%of its room-temperature energy density,demon strating notable dielectric stability under high *** attributes underscore its promising application for capacitors operating in harsh environments.

关键词： Dielectric performance Polyimide complexes Side-Chain-Type High-temperature capacitor

"Win-Win" Scenario of High Energy Density and Long Cycling Life in a Novel Na3.9MnCr0.9Zr0.1（PO4）3 Cathode

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Energy & Environmental Materials 2024年第1期7卷 87-94页

作者： Yao Wang Yukun Liu Pingge He Junteng Jin Xudong Zhao Qiuyu Shen Jie Li Xuanhui Qu Yongchang Liu Lifang Jiao Beijing Advanced Innovation Center for Materials Genome engineering State Key Laboratory for Advanced Metals and Materials Institute for Advanced Materials and Technology University of Science and Technology Beijing Department of Chemistry and Biochemistry University of California Tianjin Key Laboratory for photoelectric Materials and Devices School of Materials Science and Engineering Tianjin University of Technology Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Nankai University

The development of high-energy and long-lifespan NASICON-type cathode materials for sodium-ion batteries has always been a research hotspot but a daunting *** Na4MnCr（PO4）3has emerged as one of the most promising high-energy-density cathode materials owing to its threeelectron reactions,it still suffers from serious structural distortion upon repetitive charge/discharge processes caused by the Jahn-Teller active Mn3+.

关键词： high energy density mechanism investigation NASICON-type cathodes sodium-ion batteries structure modification

Strong hetero-interface interaction in 2D/2D WSe2/ZnIn2S4 heterostructures for highly-efficient photocatalytic hydrogen generation

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Journal of Energy Chemistry 2024年第10期97卷 379-387页

作者： Xu Guo Xing Liu Jing Shan Zhuo Xu Zhiming Fang Lu Wang Shengzhong Liu school of Energy Power and Mechanical Engineering North China Electric Power University Shaanxi Key Laboratory for Advanced Energy Devices School of Materials Science and Engineering Shaanxi Normal University Qinghai Advanced Energy Storage Laboratory SPIC Qinghai Photovoltaic Industry Innovation Center Co. Ltd.State Power Investment Corporation Key Laboratory of photoelectric Conversion and Utilization of Solar Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Center of Materials Science and Optoelectronics engineering University of Chinese Academy of Sciences

Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen ***,2D/2D WSe2/ZnIn2S4heterostructures with strong hetero-interface interaction and abundant contact were constructed via an impregnation-annealing *** charge transfer from ZnIn2S4to WSe2was evidenced by transient absorption spectroscopy in crafted heterostructures owing to the tight and2D face-to-face *** a result,the prepared WSe2/ZnIn2S4heterostructures exhibited boosted photocatalytic performance and a highest hydrogen evolution rate of 3.377 mmol/（g h） was achieved with an apparent quantum yield of 45.7% at 420 *** work not only provides new strategies to achieve efficient 2D/2D heterostructures but also paves the way for the development of green hydrogen in the future.

关键词： Indium compounds

Effect of nano-CaO particle on the microstructure,mechanical properties and corrosion behavior of lean Mg-1Zn alloy

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Journal of Magnesium and Alloys 2024年第2期12卷 794-814页

作者： Guangxin Shen Shaoyuan Lyu Leiting Yu Tianlu Li Chen You Xuewei Wang Minfang Chen Bin Jiang school of Materials Science and engineering Tianjin University of TechnologyTianjin 300384China Key Laboratory of Display Materials and photoelectric Device(Ministry of Education) Tianjin University of TechnologyTianjin 300384China National Demonstration Center for Experimental Function Materials Education Tianjin University of TechnologyTianjin 300384China National engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China

The effects of nano-CaO contents on the microstructure,mechanical properties and corrosion resistance of lean Mg-1Zn alloy were *** results showed that the addition of nano-CaO significantly refined the grain size and improved mechanical properties of the Mg-1Zn *** the same time,CaO reacted with molten Mg in situ to form nano-MgO,whose corrosion product in SBF solution was the same with the degradation product of Mg matrix,resulting in the enhanced compactness of the Mg(OH)_(2) layer and reduced corrosion rate of *** Mg-1Zn alloy had lower corrosion resistance due to excessively large grain size and shedding of corrosion *** composite with 0.5 wt.%CaO had the best corrosion resistance with a weight loss of 9.875 mg·y^(-1)·mm^(-2)due to the small number of Ca_(2)Mg_(6)Zn_(3) phase and suitable grain *** for composites with high content of CaO(0.7 wt.%and 1.0 wt.%),they had lower corrosion resistance due to the coexistence of large number of Ca_(2)Mg_(6)Zn_(3) and Mg_(2)Ca at grain boundaries,especially for 1.0 wt.%CaO composite,resulting from the strong micro-galvanic corrosion.

关键词： Lean Mg alloy In situ MgO Nanoparticles Grain refinement Corrosion resistance

Cooperative control for heterogeneous multi-agent systems: progress, applications, and challenges

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Science China(Information Sciences) 2024年第5期67卷 318-320页

作者： Bing YAN Peng SHI Jonathon CHAMBERS school of Electrical and Mechanical engineering Faculty of Science Engineering and TechnologyThe University of Adelaide school of engineering College of Science and Engineering University of Leicester

Cooperative control for heterogeneous multi-agent systems(MASs) is a critical and rapidly evolving field in modern automation and robotics. Characterized by the integration of agents with diverse capabilities and func... 详细信息

关键词： Multi agent systems