We presented the dielectric properties of three m aterials for bio-sample measurem entusing TH z transmission spectroscopy. The m aterials , PE, COC and PV D F, have sufficient transmittance. The results demonstrate ...We presented the dielectric properties of three m aterials for bio-sample measurem entusing TH z transmission spectroscopy. The m aterials , PE, COC and PV D F, have sufficient transmittance. The results demonstrate that PVDF membranes are suitablemedia for TH z transmission spectrum above 0.3 TH 7. However, it is not property m easure the solution sam pie because of the water existed afar active processng by ethanol. In this paper, the refractive hdex, the absorption coefficient, and the corn plex dieieccric functions in the THz region are compared for each material. From the measured dielectric properties, the loss m ethanism of TH z tadiation for each material is also discussed.展开更多
Hypersonic vehicles subjected to strong aerodynamic forces and serious aerodynamic heating require more stringent design for an infrared window. In this paper, a finite element analysis is used to present the distribu...Hypersonic vehicles subjected to strong aerodynamic forces and serious aerodynamic heating require more stringent design for an infrared window. In this paper, a finite element analysis is used to present the distributions of thermal and stress fields in the infrared window for hypersonic vehicles based on flowfield studies. A theoretical guidance is provided to evaluate the influence of aerodynamic heating and forces on infrared window materials. The aerodynamic heat flux from Mach 3 to Mach 6 flight at an altitude of 15 km in a standard atmosphere is obtained through flowfield analysis. The thermal and stress responses are then investigated under constant heat transfer coefficient boundary conditions for different Mach numbers. The numerical results show that the maximum stress is higher than the material strength at Mach 6, which means a failure of the material may occur. The maximum stress and temperatures are lower than the material strength and melting point under other conditions, so the material is safe.展开更多
基金The Natural Science Foundation of SZUgrant number:201115+5 种基金National Natural Science Foundation of Chinagrant number:61001185,61078018 and 61001057Foundation of Guangdong,Chinagrant number:LYM10113Research Fund for the Doctoral Program of Higher Educationgrant number:20104408120002
文摘We presented the dielectric properties of three m aterials for bio-sample measurem entusing TH z transmission spectroscopy. The m aterials , PE, COC and PV D F, have sufficient transmittance. The results demonstrate that PVDF membranes are suitablemedia for TH z transmission spectrum above 0.3 TH 7. However, it is not property m easure the solution sam pie because of the water existed afar active processng by ethanol. In this paper, the refractive hdex, the absorption coefficient, and the corn plex dieieccric functions in the THz region are compared for each material. From the measured dielectric properties, the loss m ethanism of TH z tadiation for each material is also discussed.
基金Project supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China （No. 51121004）, and the Fundamental Research Funds for the Central Universities （No. HIT.BRETIV.201315）, China
文摘Hypersonic vehicles subjected to strong aerodynamic forces and serious aerodynamic heating require more stringent design for an infrared window. In this paper, a finite element analysis is used to present the distributions of thermal and stress fields in the infrared window for hypersonic vehicles based on flowfield studies. A theoretical guidance is provided to evaluate the influence of aerodynamic heating and forces on infrared window materials. The aerodynamic heat flux from Mach 3 to Mach 6 flight at an altitude of 15 km in a standard atmosphere is obtained through flowfield analysis. The thermal and stress responses are then investigated under constant heat transfer coefficient boundary conditions for different Mach numbers. The numerical results show that the maximum stress is higher than the material strength at Mach 6, which means a failure of the material may occur. The maximum stress and temperatures are lower than the material strength and melting point under other conditions, so the material is safe.
