Elucidating the effect of growth periods on the quality of calcium sulfate whiskers(CSWs)prepared from calcium sulfate dihydrate(DH)is imperative.Herein,crystal seeds and whiskers were prepared from DH in a water–gly...Elucidating the effect of growth periods on the quality of calcium sulfate whiskers(CSWs)prepared from calcium sulfate dihydrate(DH)is imperative.Herein,crystal seeds and whiskers were prepared from DH in a water–glycerol system.Longer whiskers were obtained from crystal seeds prepared via hydration of DH for 30 s than via ball milling for 5 min followed by hydration for 20 s.The attachment of cetyltrimethyl ammonium bromide and glycerol additives to the whisker tops promoted whisker growth.The whisker sponges exhibited good thermal barrier properties and compression cycle stability.展开更多
One-dimensional(1D)metals are well known for their exceptional conductivity and their ease of formation of interconnected networks that facilitate electron migration,making them promising candidates for electromagneti...One-dimensional(1D)metals are well known for their exceptional conductivity and their ease of formation of interconnected networks that facilitate electron migration,making them promising candidates for electromagnetic(EM)attenuation.However,the impedance mismatch from high conductivity and their singular mode of energy loss hinder effective EM wave dissipation.Construction of cable structures not only optimizes impedance matching but also introduces a multitude of heterojunctions,increasing attenuation modes and potentially enhancing EM wave absorption(EMA)performance.Herein,we showcase the scalable synthesis of tin(Sn)whiskers from a Ti_(2)SnC MAX phase precursor,followed by creation of a 1D tin@carbon(Sn@C)cable structure through polymerization of PDA on their surface and annealing in argon.The EMA capabilities of Sn@C significantly surpass those of uncoated Sn whiskers,with an effective absorption bandwidth reaching 7.4 GHz.Remarkably,its maximum radar cross section reduction value of 27.85 dBm2 indicates its exceptional stealth capabilities.The enhanced EMA performance is first attributed to optimized impedance matching,and furthermore,the Sn@C cable structures have rich SnO2/C and Sn/SnO2 heterointerfaces and the associated defects,which increase interfacial and defect-induced polarization losses,as visually demonstrated by off-axis electron holography.The development of the Sn@C cable structure represents a notable advancement in broadening the scope of materials with potential applications in stealth technology,and this study also contributes to the understanding of how heterojunctions can improve EMA performance.展开更多
基金supported by the Degradable Plastics Engineering Research Center of Yunnan Provincial Education Department(KKPU202205001).
文摘Elucidating the effect of growth periods on the quality of calcium sulfate whiskers(CSWs)prepared from calcium sulfate dihydrate(DH)is imperative.Herein,crystal seeds and whiskers were prepared from DH in a water–glycerol system.Longer whiskers were obtained from crystal seeds prepared via hydration of DH for 30 s than via ball milling for 5 min followed by hydration for 20 s.The attachment of cetyltrimethyl ammonium bromide and glycerol additives to the whisker tops promoted whisker growth.The whisker sponges exhibited good thermal barrier properties and compression cycle stability.
基金National Natural Science Foundation of China,Grant/Award Numbers:52171033,52301263,U23A20574SEU Innovation Capability Enhancement Plan for Doctoral Students,Grant/Award Number:CXJH_SEU 24148。
文摘One-dimensional(1D)metals are well known for their exceptional conductivity and their ease of formation of interconnected networks that facilitate electron migration,making them promising candidates for electromagnetic(EM)attenuation.However,the impedance mismatch from high conductivity and their singular mode of energy loss hinder effective EM wave dissipation.Construction of cable structures not only optimizes impedance matching but also introduces a multitude of heterojunctions,increasing attenuation modes and potentially enhancing EM wave absorption(EMA)performance.Herein,we showcase the scalable synthesis of tin(Sn)whiskers from a Ti_(2)SnC MAX phase precursor,followed by creation of a 1D tin@carbon(Sn@C)cable structure through polymerization of PDA on their surface and annealing in argon.The EMA capabilities of Sn@C significantly surpass those of uncoated Sn whiskers,with an effective absorption bandwidth reaching 7.4 GHz.Remarkably,its maximum radar cross section reduction value of 27.85 dBm2 indicates its exceptional stealth capabilities.The enhanced EMA performance is first attributed to optimized impedance matching,and furthermore,the Sn@C cable structures have rich SnO2/C and Sn/SnO2 heterointerfaces and the associated defects,which increase interfacial and defect-induced polarization losses,as visually demonstrated by off-axis electron holography.The development of the Sn@C cable structure represents a notable advancement in broadening the scope of materials with potential applications in stealth technology,and this study also contributes to the understanding of how heterojunctions can improve EMA performance.
