The deformation and micro-voids formation mechanisms in ferrite / bainite（ F / B） multi-phase steel with the volume fraction of bainite less than 50% were studied by numerical simulation and experimental observation...The deformation and micro-voids formation mechanisms in ferrite / bainite（ F / B） multi-phase steel with the volume fraction of bainite less than 50% were studied by numerical simulation and experimental observation. The results show that the micro-strain concentrates at the soft / hard phase（ F / B） interface in the multi-phase steel,which should be correlated with the mechanism of incoordinate deformation. During the necking of the steel,the micro-voids initially form around the F / B interface,which also form in ferrite and bainite with the severe strain. The micro-voids in bainite are more dense and finer than those in ferrite. The failure mechanism of bainite is the coalescence of micro-voids,and the failure mechanism of ferrite is the growth and tearing of micro-voids. Due to the different failure mechanisms of ferrite and bainite,a suitable part of soft phase would be beneficial to the capability of anti-failure of F / B multi-phase steel during the ductile fracture.展开更多
The Williamson-Hall and uniaxial compression methods were used to study the variations of the micro-strain and stress-strain relations in WC powders after jet milling and ball milling, respectively. The rupture behavi...The Williamson-Hall and uniaxial compression methods were used to study the variations of the micro-strain and stress-strain relations in WC powders after jet milling and ball milling, respectively. The rupture behavior of agglomerates in WC powders was investigated. Meanwhile, the as-obtained WC powders treated by different milling methods were used to fabricate WC-10%Co cemented carbides, followed by the performance assessment of cemented carbides. The results show that the micro-strain of the jet-milled WC powders decreases significantly compared with that of the ball-milled WC powders, and that the cemented carbides prepared by jet-milled WC powders exhibit excellent properties with a transverse-rupture strength of 4260 MPa, due to the elimination of agglomerates and the reduction of lattice strain.展开更多
Perovskite solar cells offer great potential as a sustainable power source for distributed electronic devices that operate indoors.However,the impact of advanced lighting technology,especially the widely used pulse wi...Perovskite solar cells offer great potential as a sustainable power source for distributed electronic devices that operate indoors.However,the impact of advanced lighting technology,especially the widely used pulse width modulation(PWM)technology,on perovskite photovoltaics has been ignored.Herein,for the first time in photovoltaics,we find that the light impact emitted by the PWM lighting system caused dynamic strain in perovskite thin films,induced phase separation,and accelerated the generation of metallic lead(Pb^(0))defects,leading to irreversible degradation of the cell performance after 27 h(T_(80)).To address this issue,formamidinium triiodide(FAI_(3))is chosen to treat the surface of the perovskite and release residual stress,resulting in reduced lattice deformation during dynamic strain processes.Meanwhile,it suppresses harmful Pb0 defects and reduces Voc loss at low light intensity.The champion device achieves impressive power conversion efficiency(PCE)of 35.14%and retains 99.5%of the initial PCE after continuous strobe light soaking for 2160 h.展开更多
<div style="text-align:justify;"> An in-fiber axial micro-strain sensor based on a Few Mode Fiber Bragg Grating (FM-FBG) is proposed and experimentally characterized. This FM-FBG is in inscribed in a m...<div style="text-align:justify;"> An in-fiber axial micro-strain sensor based on a Few Mode Fiber Bragg Grating (FM-FBG) is proposed and experimentally characterized. This FM-FBG is in inscribed in a multi-layer few-mode fiber (ML-FMF), and could acquire the change of the axial strain along fibers, which depends on the transmission dips. On account of the distinct dual-mode property, a good stability of this sensor is realized. The two transmission dips could have the different sensing behaviors. Both the propagation characteristics and operation principle of such a sensor are demonstrated in detail. High sensitivity of the FM-FBG, ~4 pm/με and ~4.5 pm/με within the range of 0 με - 1456 με, is experimentally achieved. FM-FBGs could be easily scattered along one fiber. So this sensor may have a great potential of being used in sensor networks. </div>展开更多
This paper firstly and experimentally demonstrates an in-fiber axial micro-strain sensing head,combined with a Mach-Zehnder interferometer(MZI)based on the concentric multilayer elliptical-core fiber(CMECF).This MZI w...This paper firstly and experimentally demonstrates an in-fiber axial micro-strain sensing head,combined with a Mach-Zehnder interferometer(MZI)based on the concentric multilayer elliptical-core fiber(CMECF).This MZI with a high extinction ratio(about 15dB)is successfully achieved with a CMECF-single mode fiber-CMECF(CSC)structure.The MZI sensor theory and the resonance demodulation technology are systematically described in this paper.In this CSC structure, two sections of the CMECF have a role as the mode generator and coupler,respectively.LP01 and LPlleven,which have similar excitation coefficients,are two dominated propagating mode groups supported in the CMECF.On account of the distinct dual-mode property,a good stability of this sensor is realized.The detected resonance in the MZI shifts as the axial micro-strain variated due to the strong interaction between higher order modes.High sensitivity of^1.78pm/με is experimentally achieved within the range of 0με-1250με,meanwhile,the intensity fluctuation is below 0.38dB.展开更多
基金Item Sponsored by National Basic Research Program of China(2010CB630801)
文摘The deformation and micro-voids formation mechanisms in ferrite / bainite（ F / B） multi-phase steel with the volume fraction of bainite less than 50% were studied by numerical simulation and experimental observation. The results show that the micro-strain concentrates at the soft / hard phase（ F / B） interface in the multi-phase steel,which should be correlated with the mechanism of incoordinate deformation. During the necking of the steel,the micro-voids initially form around the F / B interface,which also form in ferrite and bainite with the severe strain. The micro-voids in bainite are more dense and finer than those in ferrite. The failure mechanism of bainite is the coalescence of micro-voids,and the failure mechanism of ferrite is the growth and tearing of micro-voids. Due to the different failure mechanisms of ferrite and bainite,a suitable part of soft phase would be beneficial to the capability of anti-failure of F / B multi-phase steel during the ductile fracture.
基金Project(2016GZ0290) supported by the Key Technology R&D Program of Sichuan Province,ChinaProject(2019CDXYCL0031) supported by the Fundamental Research Funds for the Central Universities,China
文摘The Williamson-Hall and uniaxial compression methods were used to study the variations of the micro-strain and stress-strain relations in WC powders after jet milling and ball milling, respectively. The rupture behavior of agglomerates in WC powders was investigated. Meanwhile, the as-obtained WC powders treated by different milling methods were used to fabricate WC-10%Co cemented carbides, followed by the performance assessment of cemented carbides. The results show that the micro-strain of the jet-milled WC powders decreases significantly compared with that of the ball-milled WC powders, and that the cemented carbides prepared by jet-milled WC powders exhibit excellent properties with a transverse-rupture strength of 4260 MPa, due to the elimination of agglomerates and the reduction of lattice strain.
基金This work was supported by the National Natural Science Foundation of China(52332008,52025028,and 52202273)the Natural Science Foundation of Jiangsu Province(BK20210728)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.
文摘Perovskite solar cells offer great potential as a sustainable power source for distributed electronic devices that operate indoors.However,the impact of advanced lighting technology,especially the widely used pulse width modulation(PWM)technology,on perovskite photovoltaics has been ignored.Herein,for the first time in photovoltaics,we find that the light impact emitted by the PWM lighting system caused dynamic strain in perovskite thin films,induced phase separation,and accelerated the generation of metallic lead(Pb^(0))defects,leading to irreversible degradation of the cell performance after 27 h(T_(80)).To address this issue,formamidinium triiodide(FAI_(3))is chosen to treat the surface of the perovskite and release residual stress,resulting in reduced lattice deformation during dynamic strain processes.Meanwhile,it suppresses harmful Pb0 defects and reduces Voc loss at low light intensity.The champion device achieves impressive power conversion efficiency(PCE)of 35.14%and retains 99.5%of the initial PCE after continuous strobe light soaking for 2160 h.
文摘<div style="text-align:justify;"> An in-fiber axial micro-strain sensor based on a Few Mode Fiber Bragg Grating (FM-FBG) is proposed and experimentally characterized. This FM-FBG is in inscribed in a multi-layer few-mode fiber (ML-FMF), and could acquire the change of the axial strain along fibers, which depends on the transmission dips. On account of the distinct dual-mode property, a good stability of this sensor is realized. The two transmission dips could have the different sensing behaviors. Both the propagation characteristics and operation principle of such a sensor are demonstrated in detail. High sensitivity of the FM-FBG, ~4 pm/με and ~4.5 pm/με within the range of 0 με - 1456 με, is experimentally achieved. FM-FBGs could be easily scattered along one fiber. So this sensor may have a great potential of being used in sensor networks. </div>
文摘This paper firstly and experimentally demonstrates an in-fiber axial micro-strain sensing head,combined with a Mach-Zehnder interferometer(MZI)based on the concentric multilayer elliptical-core fiber(CMECF).This MZI with a high extinction ratio(about 15dB)is successfully achieved with a CMECF-single mode fiber-CMECF(CSC)structure.The MZI sensor theory and the resonance demodulation technology are systematically described in this paper.In this CSC structure, two sections of the CMECF have a role as the mode generator and coupler,respectively.LP01 and LPlleven,which have similar excitation coefficients,are two dominated propagating mode groups supported in the CMECF.On account of the distinct dual-mode property,a good stability of this sensor is realized.The detected resonance in the MZI shifts as the axial micro-strain variated due to the strong interaction between higher order modes.High sensitivity of^1.78pm/με is experimentally achieved within the range of 0με-1250με,meanwhile,the intensity fluctuation is below 0.38dB.
