HgCdTe多层异质结技术是未来主流红外探测器发展的重要技术方向,在高工作温度、双/多色和雪崩光电管等高性能红外探测器中扮演着重要的角色。近年来基于多层异质结构的Hg Cd Te高工作温度红外探测器得到了快速发展,尤其是以势垒阻挡型...HgCdTe多层异质结技术是未来主流红外探测器发展的重要技术方向,在高工作温度、双/多色和雪崩光电管等高性能红外探测器中扮演着重要的角色。近年来基于多层异质结构的Hg Cd Te高工作温度红外探测器得到了快速发展,尤其是以势垒阻挡型和非平衡工作P~+-π(ν)-N~+结构为主的器件受到了广泛的研究。本文系统介绍了势垒阻挡型和非平衡工作P~+-π(ν)-N~+结构HgCdTe红外探测器的暗电流抑制机理,分析了制约两种器件结构发展的关键问题,并对国内外的研究进展进行了综述。对多层异质结构Hg CdTe红外探测器的发展进行了总结与展望。展开更多
A temperature field numerical simulation is carried out using the finite element method for laser soldering on PECT (piezoelectric ceramics transformer). A three dimensional model of laser soldering temperature field ...A temperature field numerical simulation is carried out using the finite element method for laser soldering on PECT (piezoelectric ceramics transformer). A three dimensional model of laser soldering temperature field of multilayer materials is established. Then, the model was simplified in order to perform an efficient finite element analysis. Moreover, the temperature distribution characteristic in the laser soldering is investigated and verified by experiments. In all cases, the numerical results are in good agreement with the experimental measurements.展开更多
The heterogeneous multilayer interface of VN/Ag coatings and transition multilayer interface of VN/Ag coatings were prepared on Inconel 781 and Si(100),and the microstructures,mechanical and tribological properties we...The heterogeneous multilayer interface of VN/Ag coatings and transition multilayer interface of VN/Ag coatings were prepared on Inconel 781 and Si(100),and the microstructures,mechanical and tribological properties were investigated from 25 to 700℃.The results showed that the surface roughness and average grain size of VN/Ag coatings with transition multilayer interface are obviously larger than those of VN/Ag coatings with heterogeneous multilayer interface.The coatings with transition multilayer interface have higher adhesion force and hardness than the coatings with heterogeneous multilayer interface,and both coatings can effectively restrict the initiation and propagation of microcracks.Both coatings have excellent self-adaptive lubricating properties with a decrease of friction coefficient as the temperature increases,but their wear rates reveal a drastic increase.The phase composition of the worn area of both coatings was investigated,which indicates that a smooth Ag,Magnéli phase(V2O5)and bimetallic oxides(Ag3VO4 and AgVO3)can be responsible to the excellent lubricity of both coatings.To sum up,the coatings with transition multilayer interface have excellent adaptive lubricating properties and can properly control the diffusion rate and release rate of the lubricating phase,indicating that they have great potential in solving the problem of friction and wear of mechanical parts.展开更多
Regulating charge transfer to achieve specific transfer path can improve electron utilization and complete efficient photoreduction of CO_(2).Here,we fabricated a S-scheme heterojunction of CN/Fe-MOF by an in-situ ass...Regulating charge transfer to achieve specific transfer path can improve electron utilization and complete efficient photoreduction of CO_(2).Here,we fabricated a S-scheme heterojunction of CN/Fe-MOF by an in-situ assembly strategy.The S-scheme charge transfer mechanism was confirmed by band structure,electron spin resonance(ESR)and work function(Φ)analysis.On the one hand,the response of Fe-MOF in the visible region improved the utilization of light energy,thus increasing the ability of CN/Fe-MOF to generate charge carriers.On the other hand,CN,as the active site,not only had strong adsorption capacity for CO_(2),but also retained photogenerated electrons with high reduction capacity because of S-scheme charge transfer mechanism.Hence,in the absence of any sacrificial agent and cocatalyst,the optimized 50CN/Fe-MOF obtained the highest CO yield(19.17μmol g^(–1))under UV-Vis irradiation,which was almost 10 times higher than that of CN.In situ Fourier transform infrared spectra not only revealed that the photoreduction of CO_(2) occurred at the CN,but also demonstrated that the S-scheme charge transfer mechanism enabled 50CN/Fe-MOF to have a stronger ability to generate HCOO–than CN.展开更多
文摘HgCdTe多层异质结技术是未来主流红外探测器发展的重要技术方向,在高工作温度、双/多色和雪崩光电管等高性能红外探测器中扮演着重要的角色。近年来基于多层异质结构的Hg Cd Te高工作温度红外探测器得到了快速发展,尤其是以势垒阻挡型和非平衡工作P~+-π(ν)-N~+结构为主的器件受到了广泛的研究。本文系统介绍了势垒阻挡型和非平衡工作P~+-π(ν)-N~+结构HgCdTe红外探测器的暗电流抑制机理,分析了制约两种器件结构发展的关键问题,并对国内外的研究进展进行了综述。对多层异质结构Hg CdTe红外探测器的发展进行了总结与展望。
文摘A temperature field numerical simulation is carried out using the finite element method for laser soldering on PECT (piezoelectric ceramics transformer). A three dimensional model of laser soldering temperature field of multilayer materials is established. Then, the model was simplified in order to perform an efficient finite element analysis. Moreover, the temperature distribution characteristic in the laser soldering is investigated and verified by experiments. In all cases, the numerical results are in good agreement with the experimental measurements.
基金Project(51505100)supported by the National Natural Science Foundation of China
文摘The heterogeneous multilayer interface of VN/Ag coatings and transition multilayer interface of VN/Ag coatings were prepared on Inconel 781 and Si(100),and the microstructures,mechanical and tribological properties were investigated from 25 to 700℃.The results showed that the surface roughness and average grain size of VN/Ag coatings with transition multilayer interface are obviously larger than those of VN/Ag coatings with heterogeneous multilayer interface.The coatings with transition multilayer interface have higher adhesion force and hardness than the coatings with heterogeneous multilayer interface,and both coatings can effectively restrict the initiation and propagation of microcracks.Both coatings have excellent self-adaptive lubricating properties with a decrease of friction coefficient as the temperature increases,but their wear rates reveal a drastic increase.The phase composition of the worn area of both coatings was investigated,which indicates that a smooth Ag,Magnéli phase(V2O5)and bimetallic oxides(Ag3VO4 and AgVO3)can be responsible to the excellent lubricity of both coatings.To sum up,the coatings with transition multilayer interface have excellent adaptive lubricating properties and can properly control the diffusion rate and release rate of the lubricating phase,indicating that they have great potential in solving the problem of friction and wear of mechanical parts.
文摘Regulating charge transfer to achieve specific transfer path can improve electron utilization and complete efficient photoreduction of CO_(2).Here,we fabricated a S-scheme heterojunction of CN/Fe-MOF by an in-situ assembly strategy.The S-scheme charge transfer mechanism was confirmed by band structure,electron spin resonance(ESR)and work function(Φ)analysis.On the one hand,the response of Fe-MOF in the visible region improved the utilization of light energy,thus increasing the ability of CN/Fe-MOF to generate charge carriers.On the other hand,CN,as the active site,not only had strong adsorption capacity for CO_(2),but also retained photogenerated electrons with high reduction capacity because of S-scheme charge transfer mechanism.Hence,in the absence of any sacrificial agent and cocatalyst,the optimized 50CN/Fe-MOF obtained the highest CO yield(19.17μmol g^(–1))under UV-Vis irradiation,which was almost 10 times higher than that of CN.In situ Fourier transform infrared spectra not only revealed that the photoreduction of CO_(2) occurred at the CN,but also demonstrated that the S-scheme charge transfer mechanism enabled 50CN/Fe-MOF to have a stronger ability to generate HCOO–than CN.
