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UltrahighQ Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)microwave dielectric ceramics for temperature-stable millimeter-wave dielectric resonator antennas

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Journal of Advanced Ceramics 2024年第2期13卷 155-165页

作者： Guoqiang He Yu Jiang Kaixin Song Yanjun Liu Yuan Nie Wenjie Zhang Ziqi Zhao Yinghan He Xinyue Ma Xiuli Chen Xu Li Huanfu Zhou Collaborative Innovation Centre for Exploration of Hidden nonferrous metal Deposits and Development of new materials in Guangxi Key Laboratory of Nonferrous Materials and New Processing TechnologyMinistry of EducationSchool of Materials Science and EngineeringGuilin University of TechnologyGuilin 541004China College of Electronic Information Hangzhou Dianzi UniversityHangzhou 310018China

Microwave dielectric ceramics should be improved to advance mobile communication technologies further.In this study,we prepared Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics with nonstoichiometric Sr^(2+)ratios based on our previously reported SrY_(2)O_(4) microwave dielectric ceramic,which has a low dielectric constant and an ultrahigh quality factor(Q value).The ceramic exhibited a 33.6% higher Q-by-frequency(Q×f)value(Q≈12,500)at x=0.02 than SrY_(2)O_(4).All Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics exhibited pure phase structures,although variations in crystal-plane spacings were observed.The ceramics are mainly composed of Sr-O,Y1-O,and Y_(2)-O octahedra,with the temperature coefficient of the resonant frequency(τ_(f))of the ceramic increasing with Y_(2)-O octahedral distortion.The ceramic comprises uniform grains with a homogeneous elemental distribution,clear grain boundaries,and no obvious cavities at x=0.02.The Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics exhibited good microwave dielectric properties,with optimal performance observed at x=0.02(dielectric constant(εr)=15.41,Q×f=112,375 GHz,and τ_(f)=-17.44 ppm/℃).The τ_(f) value was reduced to meet the temperaturestability requirements of 5G/6G communication systems by adding CaTiO_(3),with Sr_(1.02)Y_(2)O_(4.02)+2wt% CaTiO_(3) exhibiting ε_(r)=16.14,Q×f=51,004 GHz,andτf=0 ppm/℃.A dielectric resonator antenna prepared using Sr_(1.02)Y_(2)O_(4.02)+2wt%CaTiO_(3) exhibited a central frequency of 26.6 GHz,with a corresponding gain and efficiency of 3.66 dBi and 83.14%,respectively.Consequently,Sr_(1.02)Y_(2)O_(4).02-based dielectric resonator antennas are suitable for use in 5G millimeter-wave band(24.5-27.5 GHz)applications.

关键词： millimeter wave microwave dielectric ceramics dielectric resonator antenna nonstoichiometric ratio

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Realizing efficient emission and triple-mode photoluminescence switching in air-stable tin(IV)-based metal halides via antimony doping and rational structural modulation

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Aggregate 2024年第1期5卷 257-269页

作者： Xuefei He Hui Peng Qilin Wei Zhijie Zhou Guolun Zhang Zhentao Du Jialong Zhao Bingsuo Zou Department of materials Physics and Chemistry State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite StructuresMOE Key Laboratory of New Processing Technology for Nonferrous Metals and Materialsand School of ResourcesEnvironment and MaterialsGuangxi UniversityNanningChina

Recently,many lead-free metal halides with diverse structures and highly efficient emission have been reported.However,their poor stability and single-mode emission color severely limit their applications.Herein,three homologous Sb^(3+)-doped zero-dimensional(0D)air-stable Sn(IV)-based metal halides with different crystal structures were developed by inserting a single organic ligand into SnCl_(4)lattice,which brings different optical properties.Under photoexcitation,(C_(25)H_(22)P)SnC_(l5)@Sb⋅CH_(4O)(Sb^(3+)−1)does not emit light,(C_(25)H_(22)P)_(2)SnC_(l6)@Sb-α(Sb^(3+)−2α)shines bright yellow emission with a photoluminescence quantum yield(PLQY)of 92%,and(C_(25)H_(22)P)_(2)SnC_(l6)@Sb-β(Sb^(3+)−2β)exhibits intense red emission with a PLQY of 78%.The above three compounds show quite different optical properties should be due to their different crystal structures and the lattice distortions.Particularly,Sb^(3+)−1 can be successfully converted into Sb^(3+)−2αunder the treatment of C_(25)H_(22)PCl solution,accompanied by a transition from nonemission to efficient yellow emission,serving as a“turn-on”photoluminescence(PL)switching.Parallelly,a reversible structure conversion between Sb^(3+)−2αand Sb^(3+)−2βwas witnessed after dichloromethane or volatilization treatment,accompanied by yellow and red emission switching.Thereby,a triple-mode tunable PL switching of off-onI-onII can be constructed in Sb^(3+)-doped Sn(IV)-based compounds.Finally,we demonstrated the as-synthesized compounds in fluorescent anticounterfeiting,information encryption,and optical logic gates.

关键词： information encryption Sb^(3+)-doping Sn(IV)-based metal halides structural modulation triple-mode

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Effect of Ga on the microstructure and properties of NiCoV alloy at different annealing temperatures

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Progress in Natural Science:materials International 2024年第2期34卷 408-419页

作者： Jin Li Peng Wang Lvxing Chen Meifeng He Jun Cheng School of materials and Chemistry University of Shanghai for Science and Technology Northwest Institute for nonferrous metal Research Shaanxi Key Laboratory of Biomedical Metal Materials

To obtain a high-entropy alloy characterized by high strength and plasticity,（NiCoV）100-xGaxx=0,5,7) was successfully prepared,cold-rolled,and heat-treated.The microstructure was analyzed to correlate Ga content with the performance of the system.The addition of Ga can produce alloying effects,including solid solution strengthening effect,second phase precipitation strengthening effect,and layer misalignment energy reduction effect.The experimental results show adding Ga elements can enrich Ni,Co,V,and Ga above the grain boundaries,causing the alloy to produce annealed twins inside.The alloy is strengthened mainly by precipitation,and the formation of the precipitation phase effectively enhances the strength of the alloy.The low stacking fault energy promotes the toughening of NiCoV but makes the plasticity of the alloy decrease.Still,the formation of annealed twins effectively increases the plasticity,which makes the alloy harder but does not reduce the plasticity too much.By comparing the experimental properties,（NiCoV）93Ga7showed the best mechanical properties at the annealing temperature of 900℃,yield strength,tensile strength and elongation of 906 MPa,1321 MPa and21.36 %,respectively.

关键词： Annealing treatment High entropy alloy Mechanical properties Precipitation strengthening Twin strengthening

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Microstructure,wear and friction behavior of CoCrAITaY-xCNTs composite coatings deposited by laser-induction hybrid cladding

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Rare metals 2024年第4期43卷 1815-1827页

作者： Sheng-Feng Zhou Yu Long Yan-Liang Yi Cheng Deng Lian-Xi Hu Institute of Advanced Wear & Corrosion Resistant and Functional materials Jinan University Wuhan National laboratory for Optoelectronics (WNLO) Huazhong University of Science and Technology MOE key laboratory of new processing technology for nonferrous metals and materials Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured Materials Guangxi University School of Mechatronics Engineering Guangdong Polytechnic Normal University School of materials Science and Engineering Harbin Institute of Technology

To improve the wear performance of CoCrAlYTa coating,part of the carbon nanotubes（CNTs）chemically reacted with Ta to form reinforcement phase（TaC）,while the other CNTs were retained as lubrication phase.Subsequently,the CoCrAlYTa-xCNTs（x=0,1,2,and 4;wt%） composite coatings were prepared by laserinduction hybrid cladding（LIHC）,and the microstructure and wear resistance of coatings were systematically analyzed.Results show that the coatings are mainly composed of TaC,y-（Co,Cr） and β-（Co,Cr）Al.As the CNTs content increases from 0 wt% to 4 wt%,the volume fraction of TaC increases from 13.11 vol% to 16.12 vol%.Meanwhile,the nano-hardness of γ-（Co,Cr） and β-（Co,Cr）Al are improved from 7.49 and 9.72 to 9.36 and 11.19 GPa,respectively.As a result,the microhardness of coating increases from HV536.25 to HV 738.16,the wear rate decreases from32.4 × 10-3to 6.1 × 10-3mg·m-1,and the average friction coefficient decreases from 0.55 to 0.44.The good wear performance of the coating is attributed to the formation of TaC and the existence of remained CNTs lubricant film.

关键词： Carbon nanotube MCrAlY coating Friction and wear performance Laser-induction hybrid cladding

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Boron nitride microribbons strengthened and toughened alumina composite ceramics with excellent mechanical,dielectric,and thermal conductivity properties

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Journal of Advanced Ceramics 2024年第4期13卷 496-506页

作者： Jilin Wang Dongping Lu Weiping Xuan Yuchun Ji Ruiqi Chen Shaofei Li Wenbiao Li Wenzhuo Chen Shilin Tang Guoyuan Zheng Fei Long Guangxi key laboratory of Optical and Electronic materials and Devices Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of ResourcesSchool of Materials Science and EngineeringGuilin University of TechnologyGuilin 541004China key laboratory of new processing technology for nonferrous metals and materials of Ministry of Education Guilin University of TechnologyGuilin 541004China School of materials Science and Engineering Peking UniversityBeijing 100871China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityKowloon 999077Hong KongChina

Aluminum oxide(Al_(2)O_(3))ceramics have been widely utilized as circuit substrates owing to their exceptional performance.In this study,boron nitride microribbon(BNMR)/Al_(2)O_(3)composite ceramics are prepared using spark plasma sintering(SPS).This study examines the effect of varying the amount of toughened phase BNMR on the density,mechanical properties,dielectric constant,and thermal conductivity of BNMR/Al_(2)O_(3)composite ceramics while also exploring the mechanisms behind the toughening and increased thermal conductivity of the fabricated ceramics.The results showed that for a BNMR content of 5 wt%,BNMR/Al_(2)O_(3)composite ceramics displayed more enhanced characteristics than pure Al_(2)O_(3)ceramics.In particular,the relative density,hardness,fracture toughness,and bending strength were 99.95%±0.025%,34.11±1.5 GPa,5.42±0.21 MPa·m1/2,and 375±2.5 MPa,respectively.These values represent increases of 0.76%,70%,35%,and 25%,respectively,compared with the corresponding values for pure Al_(2)O_(3)ceramics.Furthermore,during the SPS process,BNMRs are subjected to high temperatures and pressures,resulting in the bending and deformation of the Al_(2)O_(3)matrix;this leads to the formation of special thermal pathways within it.The dielectric constant of the composite ceramics decreased by 25.6%,whereas the thermal conductivity increased by 45.6%compared with that of the pure Al_(2)O_(3)ceramics.The results of this study provide valuable insights into ways of enhancing the performance of Al_(2)O_(3)-based ceramic substrates by incorporating novel BNMRs as a second phase.These improvements are significant for potential applications in circuit substrates and related fields that require high-performance materials with improved mechanical properties and thermal conductivities.

关键词： boron nitride microribbons/aluminum oxide(BNMRs/Al_(2)O_(3))composite ceramics boron nitride microribbon(BNMR) spark plasma sintering(SPS) strengthening and toughening thermal conductivity

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Coupling Co-Ni phosphides for energy-saving alkaline seawater splitting

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Nano Research 2024年第6期17卷 4797-4806页

作者： Weijia Liu Wenxian Liu Tong Hou Junyang Ding Zhigui Wang Ruilian Yin Xingyuan San Ligang Feng Jun Luo Xijun Liu State key laboratory of Featured metal materials and Life-cycle Safety for Composite Structures Guangxi Key Laboratory of Processing for Nonferrous Metals and Featured MaterialsMOE Key Laboratory of New Processing Technology for Nonferrous Metals and MaterialsSchool of ResourcesEnvironment and MaterialsGuangxi UniversityNanning 530004China College of materials Science and Engineering Zhejiang University of TechnologyHangzhou 310014China Hebei key laboratory of Optic-electronic Information and materials the College of Physics Science and TechnologyHebei UniversityBaoding 071002China School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China ShenSi Lab Shenzhen Institute for Advanced StudyUniversity of Electronic Science and Technology of ChinaShenzhen 518110China

The coupling of energy-saving small molecule conversion reactions and hydrogen evolution reaction(HER)in seawater electrolytes can reduce the energy consumption of seawater electrolysis and mitigate chlorine corrosion issues.However,the fabrication of efficient multifunctional catalysts for this promising technology is of great challenge.Herein,a heterostructured catalyst comprising CoP and Ni_(2)P on nickel foam(CoP/Ni_(2)P@NF)is reported for hydrazine oxidation(HzOR)-assisted alkaline seawater splitting.The coupling of CoP and Ni_(2)P optimizes the electronic structure of the active sites and endows excellent electrocatalytic performance for HzOR and HER.Impressively,the two-electrode HzOR-assisted alkaline seawater splitting(OHzS)cell based on the CoP/Ni_(2)P@NF required only 0.108 V to deliver 100 mA·cm^(−2),much lower than 1.695 V for alkaline seawater electrolysis cells.Moreover,the OHzS cell exhibits satisfactory stability over 48 h at a high current density of 500 mA·cm^(−2).Furthermore,the CoP/Ni_(2)P@NF heterostructured catalyst also efficiently catalyzed glucose oxidation,methanol oxidation,and urea oxidation in alkaline seawater electrolytes.This work paves a path for high-performance heterostructured catalyst preparation for energy-saving seawater electrolysis for H_(2) production.

关键词： seawater splitting heterostructure electrocatalysis hydrazine oxidation reaction hydrogen evolution reaction

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Preparation of NiTip/Al composites with controllable phase transformation and damping behavior by friction stir processing

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Science China(Technological Sciences) 2024年第2期67卷 597-607页

作者： WU Xiao JIANG HongJie LI WangYun LIU ChongYu HUANG HongFeng LIU ShuHui WEI LiLi School of Material Science and Engineering Guilin University of Technology Guilin 541004China key laboratory of new processing technology for nonferrous metal&materials Ministry of EducationGuilin University of Technology Guilin 541004China School of Mechanical and Electrical Engineering Guilin University of Electronic TechnologyGuilin 541004China

The NiTip/1060Al composites were prepared using a pre-aging and friction stir method(FSP)to enhance the low-temperature damping performance of the aluminum alloy and accommodate various service temperatures.The bonding between NiTi particles and the 1060Al matrix is well established after FSP,and no new phases are formed in the composites.The phasetransformation peak temperature of NiTip/1060Al composites gradually shifts to lower temperatures with increased aging temperature of NiTi particles.At room temperature,the 550℃-NiTip/1060Al composite exhibits superior damping performance,with an internal friction value 144%higher than that of the FSP-1060Al alloy.However,at-91℃,the 650℃-NiTip/1060Al composite demonstrates better damping performance,with an internal friction value 158%higher than that of the FSP-1060Al alloy.The NiTip/1060Al composites exhibit the internal friction peak of NiTi phase-transformation in the temperature range from-91℃to 60℃.This characteristic results in significantly better damping performance compared to the FSP-1060Al alloy and other high-damping aluminum matrix composites.

关键词： NiTi particle aluminum matrix composites phase transformation damping behavior friction stir processing

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In-situ polymerized PEO-based solid electrolytes contribute better Li metal batteries:Challenges,strategies,and perspectives

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Journal of Energy Chemistry 2024年第5期92卷 548-571页

作者： Zhihui Jia Yong Liu Haoming Li Yi Xiong Yingjie Miao Zhongxiu Liu Fengzhang Ren School of materials Science and Engineering Henan Key Laboratory of Non-Ferrous Materials Science&Processing TechnologyHenan University of Science and TechnologyLuoyang 471023HenanChina Provincial and Ministerial Co-construction of Collaborative Innovation Center for Non-ferrous metal new materials and Advanced processing technology Henan University of Science and TechnologyLuoyang 471023HenanChina

Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with good electrochemical stability and excellent Li salt solubility are considered as one of the most promising SPEs for solid-state lithium metal batteries(SSLMBs).However,PEO-based SPEs suffer from low ionic conductivity at room temperature and high interfacial resistance with the electrodes due to poor interfacial contact,seriously hindering their practical applications.As an emerging technology,in-situ polymerization process has been widely used in PEO-based SPEs because it can effectively increase Li-ion transport at the interface and improve the interfacial contact between the electrolyte and electrodes.Herein,we review recent advances in design and fabrication of in-situ polymerized PEO-based SPEs to realize enhanced performance in LMBs.The merits and current challenges of various SPEs,as well as their stabilizing strategies are presented.Furthermore,various in-situ polymerization methods(such as free radical polymerization,cationic polymerization,anionic polymerization)for the preparation of PEO-based SPEs are summarized.In addition,the application of in-situ polymerization technology in PEO-based SPEs for adjustment of the functional units and addition of different functional filler materials was systematically discussed to explore the design concepts,methods and working mechanisms.Finally,the challenges and future prospects of in-situ polymerized PEO-based SPEs for SSLMBs are also proposed.

关键词： In-situ polymerization Polyethylene oxide Solid polymer electrolytes Lithium metal anodes

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Effect of Molecular Weight on Thermoelectric Performance of P3HT Analogues with 2-Propoxyethyl Side Chains

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Journal of Wuhan University of technology(materials Science) 2024年第2期39卷 268-281页

作者：董得福 WANG Wei ZHAN Chun LI Chenglong ZHOU Qisheng 肖生强 State key laboratory of Advanced technology for materials Synthesis and processing Wuhan University of TechnologyWuhan 430070China

By replacing hexyl chains in poly(3-hexylthiophene)(P3HT)with 2-propoxyethyls,four poly(3-(2-propoxyethyl)thiophene)(P3POET)homopolymers with comparable polydispersity indexes(PDI)and regioregularities were prepared herein in addition with step increment of about 7 kDa on numberaverage molecular weight(M_(n))from around 11 to 32 kDa(accordingly denoted as P11k,P18k,P25k,and P32k).When doped in film by FeCl_(3)at the optimized conditions,the maximum power factor(PF_(max))increases greatly from 4.3μW·m^(-1)·K^(-2)for P11k to 8.8μW·m^(-1)·K^(-2)for P18k,and further to 9.7μW·m^(-1)·K^(-2)for P25k,followed by a slight decrease to 9.2μW·m^(-1)·K^(-2)for P32k.The close Seebeck coefficients(S)at PF_(max)are observed in these doped polymer films due to their consistent frontier orbital energy levels and Fermi levels.The main contribution to this PF_(max)evolution thus comes from the corresponding conductivities(σ).Theσvariation of the doped films can be rationally correlated with their microstructure evolution.

关键词： conjugated polymer molecular weight microstructure thermoelectric performance

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Exceptional electrostrain with minimal hysteresis and superior temperature stability under low electric field in KNN-based lead-free piezoceramics

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Journal of Advanced Ceramics 2024年第3期13卷 364-372页

作者： Huan Liu Yijin Hao Ziqi Yang Tianyi Feng Bin Su Xin Zhang Mengping Xue Bo-Ping Zhang Jing-Feng Li Beijing Municipal key laboratory of new Energy materials and Technologies School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China State key laboratory of new Ceramics and Fine processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Over the past two decades,(K_(0.5)Na_(0.5))NbO_(3)(KNN)-based lead-free piezoelectric ceramics have made significant progress.However,attaining a high electrostrain with remarkable temperature stability and minimal hysteresis under low electric fields has remained a significant challenge.To address this long-standing issue,we have employed a collaborative approach that combines defect engineering,phase engineering,and relaxation engineering.The LKNNS-6BZH ceramic,when sintered at T_(sint)=1170℃,demonstrates an impressive electrostrain with a d_(33) value of 0.276%and 1379 pm·V^(-1)under 20 kV·cm^(-1),which is comparable to or even surpasses that of other lead-free and Pb(Zr,Ti)O_(3)ceramics.Importantly,the electrostrain performance of this ceramic remains stable up to a temperature of 125℃,with the lowest hysteresis observed at 9.73%under 40 kV·cm^(-1).These excellent overall performances are attributed to the presence of defect dipoles involving V′_(A)-V∙∙_(O) and B′_(Nb)-V∙∙O,the coexistence of R-O-T multiphase,and the tuning of the trade-off between long-range ordering and local heterogeneity.This work provides a lead-free alternative for piezoelectric actuators and a paradigm for designing piezoelectric materials with outstanding comprehensive performance under low electric fields.

关键词： lead-free piezoelectric ceramics temperature stability electrostrain potassium sodium niobate low hysteresis

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