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Generation and Suppression of Pendant Droplet Oscillation in Electron Beam Directed Energy Deposition

Engineering 2024年第6期37卷 215-229页

作者： Zhiyue Liang Zhenyu Liao Haoyu Zhang Zixiang Li Li Wang Baohua Chang Dong Du Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationTsinghua UniversityBeijing 100084China

Electron beam–directed energy deposition(EB–DED)has emerged as a promising wire-based metal additive manufacturing ***,the effects of EBs on pendant droplets at wire tips have not yet been *** aim of this study is to enhance the understanding of this action by analyzing the mechanism of droplet *** pendant droplet oscillation phenomenon hinders the stable transfer of droplets to the molten pool and limits the feasibility of manufacturing complex lattice structures by EB–***,another aim of this study is to create an oscillation suppression *** escalating asymmetric amplitude is the main characteristic of droplet *** primary oscillationinducing force is the recoil force generated from the EB-acted local surface of the *** physical mechanism of this force is the rapid increase and uneven distribution of the local surface temperature caused by the partial action of the *** prerequisites for droplet oscillation include vacuum conditions,high power densities,and bypass wire feeding *** proposed EB–dynamic surrounding melting(DSM)method can be applied to conveniently and effectively suppress oscillations,enable the accurate transfer of droplets to the molten pool,and achieve stable processes for preparing the strut elements of lattice *** the temperature and improving the uniformity of its distribution are the mechanisms of oscillation suppression in EB–*** this study,the physical basis for interpreting the mechanism by which EBs act on droplets and the technical basis for using EB–DED to prepare complex lattice structure parts are provided.

关键词： Additive manufacturing Electron beam freeform fabrication In situ monitoring Pendant droplet

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Cyclic Pulsating Pressure Enhanced Segregating Structuration of Ultra-High Molecular Weight Polyethylene/Graphene Composites as High-performance Light-Weight EMI Shields

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Chinese Journal of Polymer Science 2024年第7期42卷 958-967,I0008页

作者： Yun-Zhi Huang Xiao-Xiao Liu Lan-Wei Li Guang-Ming Huang Zhao-Xia Huang Jin-Ping Qu National Engineering Research Center of Novel Equipment for Polymer Processing Key Laboratory of Polymer Processing EngineeringMinistry of EducationGuangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced ManufacturingSchool of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhou 510641China School of Advanced Manufacturing Technology Guangdong Mechanical&Electrical PolytechnicGuangzhou 510550China

Currently,the enhancement in electromagnetic interference(EMI)performance of polymeric composite generally relies on either improving electrical conductivity(σ)for stronger electromagnetic(EM)reflections or tailoring structure for higher EM ***,we proposed a novel technique called cyclic pulsating pressure enhanced segregating structuration(CPP-SS),which can reinforce these two factors *** structural information was supplied by optical microscopy(OM)and scanning electron microscopy(SEM),both of which confirmed the formation and evolution of segregate structured ultra-high molecular weight polyethylene(UHMWPE)/graphene ***,the result showed that CPP-SS can significantly improve theσof ***,advanced specific EMI shielding efficiency of 31.1 d B/mm was achieved for UHMWPE/graphene composite at 1-mm thickness and a low graphene loading of 5 wt%.Meanwhile,it also confirmed that the intrinsic disadvantage of poor mechanical properties of conventional segregated structure composites can be *** work is believed to provide a fundamental understanding of the structural and performance evolutions of segregated structured composites prepared under CPPSS,and to bring us a simple and efficient approach for fabricating high-performance,strong and light-weight polymeric EMI shields.

关键词： Cyclic pulsating pressure Segregated structure Ultra-high molecular weight polyethylene Graphene Electromagnetic interface

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3D-printable Boron Nitride/Polyacrylic Hydrogel Composites with High Thermal Conductivities

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Journal of Wuhan University of technology(materials Science) 2024年第5期39卷 1303-1310页

作者： DAI Jialei XUE Bingyu QIAN Qi HE Wenhao ZHU Chenglong LEI Liwen WANG Kun XIE Jingjing Hubei Longzhong Laboratory Xiangyang 441000China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Polyacrylic acid(PAA)hydrogel composites with different hexagonal boron nitride(h-BN)fillers were synthesized and successfully 3D-printed while their thermal conductivity was systematically *** the content of h-BN increasing from 0.1 wt%to 0.3 wt%,the thermal conductivity of the 3D-printed composites has been ***,through the shear force given by the 3D printer,a complete thermal conductivity path is obtained inside the hydrogel,which significantly improves the thermal conductivity of the h-BN hydrogel *** maximum thermal conductivity is 0.8808 W/(m·K),leading to a thermal conductive enhancement of 1000%,compared with the thermal conductivity of pure PAA *** study shows that using h-BN fillers can effectively and significantly improve the thermal conductivity of hydrogelbased materials while its 3D-printable ability has been maintained.

关键词： hydrogel composites boron nitride 3D printing thermal conductivity

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Multifunctional 3D electrodes for tunable high-performance hybrid zinc batteries

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Journal of materials Science & technology 2024年第11期178卷 155-161页

作者： Yiming Chen Minxuan Zhou Junpeng Wu Xidan Xiao Lin Xu School of Chemistry and Materials Science Hubei Engineering UniversityXiaogan 432000China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

The high energy density and long cycling life of zinc-based batteries are restricted by the single electro-chemical reaction *** improve the electrochemical performance of batteries,electrode materials,electrolytes and membranes are regularly modified,while the construction of battery systems is often ***,a multifunctional electrode was prepared via 3D printing,which successfully coupled the metal oxide/hydroxide-zinc battery(MZB)reaction and rechargeable zinc-air battery(RZAB)*** ultrathick hierarchical 3D electrode provided a tunable capacity for the MZB system,which enabled the possibility for feasible output regulation of this hybrid *** active material NiCoLDH was discov-ered to undergo structure reconstruction during cycling,which revealed the capacity fading *** delicate system design and discovery ensured a high-performance battery configuration and revealed the corresponding mechanism,opening a new avenue for developing high-performance zinc batteries.

关键词： Zinc battery Multifunctional electrode 3D printing Hierarchical 3D structure

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Correlative Mn-Co catalyst excels Pt in oxygen reduction reaction of quasi-solid-state zinc-air batteries

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Nano Research 2024年第5期17卷 4118-4124页

作者： Tingting Wang Jincheng Huang Wei Sang Cai Zhou Bohan Zhang Wei Zhu Kang Du Zongkui Kou Shengxiang Wang School of Mathematical and Physical Sciences Wuhan Textile UniversityWuhan 430200China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Zn-air batteries(ZABs)as a class of promising energy storage setups are generally powered by efficient and robust catalysts at the oxygen-involving *** the existing non-noble catalysts have outperformed noble Pt benchmark in the alkaline liquid-state ZABs,to the best of our knowledge few have excelled Pt in quasi-solid-state(QSS)***,we found that an integrated Mn-Co cathode derived from the bimetallic Mn/Co metal organic frameworks generates a 1.4-fold greater power density in the QSS ZABs than a Pt cathode while its power density in liquid-state ZABs is only 0.8-fold of the ***,such Mn-Co catalyst delivers high-rate oxygen reduction reaction(ORR)capability with half-wave potential of 0.84 *** in-depth characterizations and analyses have demonstrated that the Co and Mn species show the specific affinity towards H_(2)O and O_(2),respectively,synergizing the ORR process in the water-deficient environment of QSS *** work has enlightened the rational design of non-noble metal catalysts to improve the power density of QSS ZABs.

关键词： non-noble metal catalysts zinc-air battery quasi-solid-state synergistic effect

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Effects of a novel refiner Al-3Ti-4.35La combined with Sr on microstructure and mechanical properties of as-cast A356 alloy

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China Foundry 2024年第6期21卷 641-650页

作者： Mei Xu Wan-wu Ding Li-wen Hu Shi-hao Chen Hai-xia Zhang Hai-cun Yu Wen-jun Zhao School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China

It is a practically significant issue to refine and modify industrial Al-Si casting alloy to improve its *** the present study,a novel refiner Al-3Ti-4.35La alloy,prepared by a melt-reaction method,was used,combined with Sr to refine the as-cast A356 *** effects on the as-cast microstructures and mechanical properties of A356 alloy were *** results indicate that the combined addition of Al-3Ti-4.35La intermediate alloy and Sr can improve the microstructure and enhance the mechanical properties of A356 *** adding 0.3wt.%Al-3Ti-4.35La and 0.03wt.%Sr to the as-cast A356 alloy,the average grain size ofα-Al decreases from 693.47μm to 264.13μm(a decrease of 61.91%),the secondary dendrite arm spacing(SDAS)is decreased by 47.8%from 32.09μm to 16.75μm,and the eutectic Si is transformed from an acicular structure to short rods and a granular *** ultimate tensile strength(UTS)and elongation(EL)of the as-cast A356 alloy modified by Al-3Ti-4.35La and Sr reach 216.3 MPa and 10.6%,which are enhanced by 29.54%and 134.66%compared with the unmodified alloy,*** fracture mode is transformed from transgranular fracture to intergranular fracture,and the ductile toughness of the alloy is *** adding the Al-3Ti-4.35La and Sr,the undercooling for the nucleation ofα-Al and eutectic Si increases,leading to an accelerated nucleation rate and an increased number of nuclei,which shortens the duration of the eutectic reaction and consequently inhibits grain growth.

关键词： A356 alloy Al-3Ti-4.35La Sr refiner grain refinement microstructure mechanical properties

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Thermodynamics aided design of hBN-capsulated diboride powders from novel nitrate precursors for high entropy ceramics

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Journal of materials Science & technology 2024年第11期178卷 133-142页

作者： Hailing Yang Ji Zou Zhimin Xiong Jingjing Liu Weimin Wang Zhengyi Fu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000China

Hexagonal BN-coated powders have been widely used in various engineering sectors,however,their pro-ductions are restricted by the complexity of gas-solid *** this study,guided by thermodynamics,a novel approach to synthesize Layer-structured hexagonal BN(hBN)-coated high entropy diboride pow-ders in vacuum was developed,using metal salt Zr(NO_(3))4·5H_(2)O,HfCl_(4),NbC_(15),TaC_(15),C_(16)H_(36)O_(4)Ti,boric acid,and sucrose as raw *** adjusting the ratio of carbon to metal source(C/M),powders only consisting of two boride solid solutions and hBN were finally obtained,under an optimal process-ing condition of C/M=5.5 and synthesis temperature of 1400 ℃.Parts of hBN were found to coat on high-entropy metal diborides ceramic(HEB)particles,corresponding formation mechanism for core-shell structured powders was investigated,together with the liquid precursor assisted boro/carbothermal re-duction *** from as-synthesized core-shell powders,(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B2-11 vol%hBN ceramics were densified at 1900 ℃ under 50 MPa without holding,with a high relative density of 97.3%.

关键词： High entropy boride Boro/carbothermal reduction Sol-gel Core-shell powders Densification

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Defect chemistry engineering of Ga-doped garnet electrolyte with high stability for solid-state lithium metal batteries

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Chinese Physics B 2024年第8期33卷 560-567页

作者：陈思汗黎俊刘可可孙笑晨万京伟翟慧宇唐新峰谭刚健 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China International School of Materials Science&Engineering Wuhan University of TechnologyWuhan 430070China

Ga-doped Li_(7)La_(3)Zr_(2)O_(12)(Ga-LLZO)has long been considered as a promising garnet-type electrolyte candidate for all-solid-state lithium metal batteries(ASSLBs)due to its high room temperature ionic ***,the typical synthesis of Ga-LLZO is usually accompanied by the formation of undesired LiGaO_(2) impurity phase that causes severe instability of the electrolyte in contact with molten Li metal during half/full cell *** this study,we show that by simply engineering the defect chemistry of Ga-LLZO,namely,the lithium deficiency level,LiGaO_(2) impurity phase is effectively inhibited in the final synthetic ***,defect chemistry engineered Ga-LLZO exhibits excellent electrochemical stability against lithium metal,while its high room temperature ionic conductivity(~1.9×10^(-3)S·cm^(-1))is well *** assembled Li/Ga-LLZO/Li symmetric cell has a superior critical current density of 0.9 mA·cm^(-2),and cycles stably for 500 hours at a current density of 0.3 mA·cm^(-2).This research facilitates the potential commercial applications of high performance Ga-LLZO solid electrolytes in ASSLBs.

关键词： Ga-doped Li_7La_3Zr_2O_(12)(Ga-LLZO) defect chemistry engineering high room temperature ionic conductivity electrochemical stability

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Revitalizing osmium-based catalysts for energy conversion

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Energy Reviews 2023年第4期2卷 81-88页

作者： Ding Chen Shichun Mu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China

Designing high cost-effective catalysts has been one of the core topics in energy conversion and *** to unique electronic structure and excellent comprehensive properties,Pt-group metal(PGM)based-materials occupy the top region of numerous volcanic curves and are currently difficult to be replaced by abundant tran-sition metal ***,we pay attention to the osmium(Os),as the cheapest and the least noticed PGM in the field of electrocatalysis,with promising application ***,the three main modification strategies(anion modulation,heterostructure construction,substrate engineering)of Os-based catalysts in hydrogen evolution reaction(HER),the structural advantages provided in oxygen evolution reaction(OER),and other energy-related electrocatalysis applications are discussed one by *** addition,we discuss the key problems and countermeasures faced in their further breakthroughs,and look forward to future development trends and ***,the insights in this work will promote the understanding and designation of Os-based catalysts.

关键词： Energy conversion Electrocatalysis Pt-group metals Os-based catalysts

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1,3,5-Trifluorobenzene endorsed EC-free electrolyte for high-voltage and wide-temperature lithium-ion batteries

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Journal of Energy Chemistry 2023年第10期85卷 49-57,I0003页

作者： Mingsheng Qin Ziqi Zeng Qiang Wu Xiaowei Liu Qijun Liu Shijie Cheng Jia Xie State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070HubeiChina

Ethylene carbonate(EC)is susceptible to the aggressive chemistry of nickel-rich cathodes,making it undesirable for high-voltage lithium-ion batteries(LIBs).The arbitrary elimination of EC leads to better oxidative tolerance but always incurs interfacial degradation and electrolyte ***,an EC-free electrolyte is deliberately developed based on gradient solvation by pairing solvation-protection agent(1,3,5-trifluorobenzene,F_(3)B)with propylene carbonate(PC)/methyl ethyl carbonate(EMC)formulation.F_(3)B keeps out of inner coordination shell but decomposes preferentially to construct robust interphase,inhibiting solvent decomposition and electrode ***,the optimized electrolyte(1.1 M)with wide liquid range(-70–77℃)conveys decent interfacial compatibility and high-voltage stability(4.6 V for LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2),NCM622),qualifying reliable operation of practical NCM/graphite pouch cell(81.1%capacity retention over 600 cycles at 0.5 C).The solvation preservation and interface protection from F_(3)B blaze a new avenue for developing high-voltage electrolytes in next-generation LIBs.

关键词： Lithium-ion batteries Solvation structure High-voltage electrolyte Wide-temperature range Interfacial chemistry

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