In this work,the mechanical properties and strengthening mechanisms induced by microstructural evolution in a rheo-extruded 5087 alloy processed via accumulative continuous extrusion forming(ACEF)were investigated.Ele...In this work,the mechanical properties and strengthening mechanisms induced by microstructural evolution in a rheo-extruded 5087 alloy processed via accumulative continuous extrusion forming(ACEF)were investigated.Electron back-scattered diffraction(EBSD)and transmission electron microscopy(TEM)were utilized to characterize the microstructure of the alloy subjected to ACEF with various passes.The grain refinement caused by continuous dynamic recrystallization(CDRX)was discussed.The results demonstrated that after 3 passes of ACEF,there was a significant grain refinement effect on the alloy,and the average grain size decreased from 45.6μm to 2.5μm;the ultimate tensile strength(UTS)and yield strength(YS)of the alloy increased to 362.8 MPa and 234.6 MPa,respectively.Dislocation cells/walls generated during deformation promoted the formation of low angle grain boundaries(LAGBs).The accumulative strain accelerated the transformation of LAGBs to high angle grain boundaries(HAGBs).Dislocation pile-up enhanced the driving force of CDRX,and nano-sized Al_6(Mn,Fe)phases at the grain boundaries inhibited the growth of grains due to the pinning effect.Based on the quantitative estimation,dislocation strengthening and grain boundary strengthening dominated the enhancement in YS of the ACEFed alloy.展开更多
We demonstrated a divided pulse amplification of burst pulse trains.The intraburst rate is 1 GHz,and the burst rate ranges from 1.5 k Hz to 15 MHz.Under the pump power of 100 W,the burst pulse energy is adjustable fro...We demonstrated a divided pulse amplification of burst pulse trains.The intraburst rate is 1 GHz,and the burst rate ranges from 1.5 k Hz to 15 MHz.Under the pump power of 100 W,the burst pulse energy is adjustable from 2.2μJ to 22 mJ.The pulse width of combined and compressed pulses is 275 fs with beam quality M^(2)of 1.2.展开更多
In an unmanned aerial vehicle ad-hoc network(UANET),sparse and rapidly mobile unmanned aerial vehicles(UAVs)/nodes can dynamically change the UANET topology.This may lead to UANET service performance issues.In this st...In an unmanned aerial vehicle ad-hoc network(UANET),sparse and rapidly mobile unmanned aerial vehicles(UAVs)/nodes can dynamically change the UANET topology.This may lead to UANET service performance issues.In this study,for planning rapidly changing UAV swarms,we propose a dynamic value iteration network(DVIN)model trained using the episodic Q-learning method with the connection information of UANETs to generate a state value spread function,which enables UAVs/nodes to adapt to novel physical locations.We then evaluate the performance of the DVIN model and compare it with the non-dominated sorting genetic algorithm II and the exhaustive method.Simulation results demonstrate that the proposed model significantly reduces the decisionmaking time for UAV/node path planning with a high average success rate.展开更多
Probes for in vivo imaging of hypochlorous acid(HOCl),one of the most important reactive oxygen species in innate immunity,are urgently needed to understand the pathogenesis of autoimmune and neuroinflammatory disorde...Probes for in vivo imaging of hypochlorous acid(HOCl),one of the most important reactive oxygen species in innate immunity,are urgently needed to understand the pathogenesis of autoimmune and neuroinflammatory disorders.As a strong oxidant,HOCl could bleach near-infrared sensors and inactivate luciferase readily,making in vivo imaging overwhelmingly challenging.Via fine-tuning of a selective HOCl sensing moiety,HOCl stable spacer,and bright chemiluminescent scaffold,we have developed HOCl-CL-510 as a highly selective and sensitive probe for HOCl detection both in vitro and in vivo.In particular,we achieved recurring real-time monitoring of HOCl in both acute and chronic inflammation models in living mice,providing a new chemical tool for dynamic monitoring of disease development with reduced usage of experimental animals.展开更多
基金supported by the National Key Research and Development Program of China[No.2018YFB2001800]the National Natural Science Foundation of China(No.51871184)+1 种基金the Dalian High-level Talents Innovation Support Program(No.2021RD06)the Dongguan Graduate Workstation Project(No.20201900300032)。
文摘In this work,the mechanical properties and strengthening mechanisms induced by microstructural evolution in a rheo-extruded 5087 alloy processed via accumulative continuous extrusion forming(ACEF)were investigated.Electron back-scattered diffraction(EBSD)and transmission electron microscopy(TEM)were utilized to characterize the microstructure of the alloy subjected to ACEF with various passes.The grain refinement caused by continuous dynamic recrystallization(CDRX)was discussed.The results demonstrated that after 3 passes of ACEF,there was a significant grain refinement effect on the alloy,and the average grain size decreased from 45.6μm to 2.5μm;the ultimate tensile strength(UTS)and yield strength(YS)of the alloy increased to 362.8 MPa and 234.6 MPa,respectively.Dislocation cells/walls generated during deformation promoted the formation of low angle grain boundaries(LAGBs).The accumulative strain accelerated the transformation of LAGBs to high angle grain boundaries(HAGBs).Dislocation pile-up enhanced the driving force of CDRX,and nano-sized Al_6(Mn,Fe)phases at the grain boundaries inhibited the growth of grains due to the pinning effect.Based on the quantitative estimation,dislocation strengthening and grain boundary strengthening dominated the enhancement in YS of the ACEFed alloy.
基金supported by the National Natural Science Foundation of China(Nos.61735001,61575004,and 11027404)。
文摘We demonstrated a divided pulse amplification of burst pulse trains.The intraburst rate is 1 GHz,and the burst rate ranges from 1.5 k Hz to 15 MHz.Under the pump power of 100 W,the burst pulse energy is adjustable from 2.2μJ to 22 mJ.The pulse width of combined and compressed pulses is 275 fs with beam quality M^(2)of 1.2.
基金Project supported by the National Natural Science Foundation of China(No.61501399)the SAIC MOTOR(No.1925)the National Key R&D Program of China(No.2018AAA0102302)。
文摘In an unmanned aerial vehicle ad-hoc network(UANET),sparse and rapidly mobile unmanned aerial vehicles(UAVs)/nodes can dynamically change the UANET topology.This may lead to UANET service performance issues.In this study,for planning rapidly changing UAV swarms,we propose a dynamic value iteration network(DVIN)model trained using the episodic Q-learning method with the connection information of UANETs to generate a state value spread function,which enables UAVs/nodes to adapt to novel physical locations.We then evaluate the performance of the DVIN model and compare it with the non-dominated sorting genetic algorithm II and the exhaustive method.Simulation results demonstrate that the proposed model significantly reduces the decisionmaking time for UAV/node path planning with a high average success rate.
基金supported by The University of Hong Kong,Morningside Foundation,Hong Kong Research Grants Council Area of Excellence Scheme(grant no.AoE/P-705/16 to D.Y.)National Natural Science Foundation of China(grant no.21961142011 to D.Y.)the Israel Science Foundation-China Joint Funding Program.
文摘Probes for in vivo imaging of hypochlorous acid(HOCl),one of the most important reactive oxygen species in innate immunity,are urgently needed to understand the pathogenesis of autoimmune and neuroinflammatory disorders.As a strong oxidant,HOCl could bleach near-infrared sensors and inactivate luciferase readily,making in vivo imaging overwhelmingly challenging.Via fine-tuning of a selective HOCl sensing moiety,HOCl stable spacer,and bright chemiluminescent scaffold,we have developed HOCl-CL-510 as a highly selective and sensitive probe for HOCl detection both in vitro and in vivo.In particular,we achieved recurring real-time monitoring of HOCl in both acute and chronic inflammation models in living mice,providing a new chemical tool for dynamic monitoring of disease development with reduced usage of experimental animals.
