研究了190~230℃低温退火对拉拔态Al-0.3La合金单丝微观组织、抗拉强度和导电率的影响。结果表明,拉拔后合金单丝的铝晶粒呈纤维状分布,平均晶粒尺寸为2.11μm,并且在基体上分布有微米级Al Fe Si La颗粒以及纳米Al Fe Si颗粒。随着退火...研究了190~230℃低温退火对拉拔态Al-0.3La合金单丝微观组织、抗拉强度和导电率的影响。结果表明,拉拔后合金单丝的铝晶粒呈纤维状分布,平均晶粒尺寸为2.11μm,并且在基体上分布有微米级Al Fe Si La颗粒以及纳米Al Fe Si颗粒。随着退火温度升高,Al Fe Si La颗粒中的La含量逐渐增加,铝基体再结晶程度加快,晶粒择优取向逐渐不明显,同时铝晶粒尺寸增加,位错密度和小角度晶界占比下降。当退火温度增加到230℃时,合金的抗拉强度由194.18 MPa降低到158.35 MPa,导电率由60.9%IACS增加到61.7%IACS。强度的降低主要由形变强化、细晶强化和固溶强化作用减弱导致;而随退火温度升高,基体中固溶La含量的下降,以及晶界数量和位错密度减小是造成合金导电率增加的主要原因。展开更多
Advanced healthcare monitors for air pollution applications pose a significant challenge in achieving a balance between high-performance filtration and multifunctional smart integration.Electrospinning triboelectric n...Advanced healthcare monitors for air pollution applications pose a significant challenge in achieving a balance between high-performance filtration and multifunctional smart integration.Electrospinning triboelectric nanogenerators(TENG)provide a significant potential for use under such difficult circumstances.We have successfully constructed a high-performance TENG utilizing a novel multi-scale nanofiber architecture.Nylon 66(PA66)and chitosan quaternary ammonium salt(HACC)composites were prepared by electrospinning,and PA66/H multiscale nanofiber membranes composed of nanofibers(≈73 nm)and submicron-fibers(≈123 nm)were formed.PA66/H multi-scale nanofiber membrane as the positive electrode and negative electrode-spun PVDF-HFP nanofiber membrane composed of respiration-driven PVDF-HFP@PA66/H TENG.The resulting PVDF-HFP@PA66/H TENG based air filter utilizes electrostatic adsorption and physical interception mechanisms,achieving PM_(0.3)filtration efficiency over 99%with a pressure drop of only 48 Pa.Besides,PVDF-HFP@PA66/H TENG exhibits excellent stability in high-humidity environments,with filtration efficiency reduced by less than 1%.At the same time,the TENG achieves periodic contact separation through breathing drive to achieve self-power,which can ensure the long-term stability of the filtration efficiency.In addition to the air filtration function,TENG can also monitor health in real time by capturing human breathing signals without external power supply.This integrated system combines high-efficiency air filtration,self-powered operation,and health monitoring,presenting an innovative solution for air purification,smart protective equipment,and portable health monitoring.These findings highlight the potential of this technology for diverse applications,offering a promising direction for advancing multifunctional air filtration systems.展开更多
文摘研究了190~230℃低温退火对拉拔态Al-0.3La合金单丝微观组织、抗拉强度和导电率的影响。结果表明,拉拔后合金单丝的铝晶粒呈纤维状分布,平均晶粒尺寸为2.11μm,并且在基体上分布有微米级Al Fe Si La颗粒以及纳米Al Fe Si颗粒。随着退火温度升高,Al Fe Si La颗粒中的La含量逐渐增加,铝基体再结晶程度加快,晶粒择优取向逐渐不明显,同时铝晶粒尺寸增加,位错密度和小角度晶界占比下降。当退火温度增加到230℃时,合金的抗拉强度由194.18 MPa降低到158.35 MPa,导电率由60.9%IACS增加到61.7%IACS。强度的降低主要由形变强化、细晶强化和固溶强化作用减弱导致;而随退火温度升高,基体中固溶La含量的下降,以及晶界数量和位错密度减小是造成合金导电率增加的主要原因。
基金financial support from the National Key Research and Development Program of China(2022YFB3804905)National Natural Science Foundation of China(22375047,22378068,and 22378071)+1 种基金Natural Science Foundation of Fujian Province(2022J01568)111 Project(No.D17005).
文摘Advanced healthcare monitors for air pollution applications pose a significant challenge in achieving a balance between high-performance filtration and multifunctional smart integration.Electrospinning triboelectric nanogenerators(TENG)provide a significant potential for use under such difficult circumstances.We have successfully constructed a high-performance TENG utilizing a novel multi-scale nanofiber architecture.Nylon 66(PA66)and chitosan quaternary ammonium salt(HACC)composites were prepared by electrospinning,and PA66/H multiscale nanofiber membranes composed of nanofibers(≈73 nm)and submicron-fibers(≈123 nm)were formed.PA66/H multi-scale nanofiber membrane as the positive electrode and negative electrode-spun PVDF-HFP nanofiber membrane composed of respiration-driven PVDF-HFP@PA66/H TENG.The resulting PVDF-HFP@PA66/H TENG based air filter utilizes electrostatic adsorption and physical interception mechanisms,achieving PM_(0.3)filtration efficiency over 99%with a pressure drop of only 48 Pa.Besides,PVDF-HFP@PA66/H TENG exhibits excellent stability in high-humidity environments,with filtration efficiency reduced by less than 1%.At the same time,the TENG achieves periodic contact separation through breathing drive to achieve self-power,which can ensure the long-term stability of the filtration efficiency.In addition to the air filtration function,TENG can also monitor health in real time by capturing human breathing signals without external power supply.This integrated system combines high-efficiency air filtration,self-powered operation,and health monitoring,presenting an innovative solution for air purification,smart protective equipment,and portable health monitoring.These findings highlight the potential of this technology for diverse applications,offering a promising direction for advancing multifunctional air filtration systems.
