Over the Asian continent,high aerosol loading is critical to ensure the high accuracy of CO_2 retrieval in the near infrared absorption band.Simulations were performed to explore the effect of light path modification ...Over the Asian continent,high aerosol loading is critical to ensure the high accuracy of CO_2 retrieval in the near infrared absorption band.Simulations were performed to explore the effect of light path modification by aerosol son the atmospheric CO_2 near infrared band(6140-6270 cm^(-1)).The Vector LInearized Discrete Ordinate Radiative Transfer(VLIDORT) model and the Line-By-Line Radiative Transfer Model(LBLRTM) were used for forward calculations.The U.S.standard atmosphere was used for atmospheric profiles.The results indicate that the aerosols caused similar effects to increases in CO_2 in the planetary boundary layer and became more significant with aerosol layer rising while aerosol optical depth was 0.1.This effect will cause an over estimation of the CO_2 mixing ratio in the retrieval process and an under estimation in the aerosol layer.The results also indicate that the effect of urban and industrial aerosols is smaller than that of non-absorbing and dust aerosols because of the nearly constant absorption properties in the near infrared band.展开更多
Thermosensitive strontium titanate(SrTiO3)as a ferroelectric crystal with great tunability in microwave and terahertz band shows unparalleled potential value.Utilizing the thermal electromagnetic tunability to achieve...Thermosensitive strontium titanate(SrTiO3)as a ferroelectric crystal with great tunability in microwave and terahertz band shows unparalleled potential value.Utilizing the thermal electromagnetic tunability to achieve the intelligent manipulation,a thermal-tunable metamaterial with terahertz-band absorption based on SrTiO3 crystal was proposed in this paper.The absorbent metamaterial(AM)is formed by Floquet’s linear periodic arranged unit,which is composed of a metallic ground plane and embedded cross SrTiO3 material in rhombic metallic patch,and separated by FR-4 dielectric spacer.The broadband frequency tunability of AM was operated by changing the temperature.The permittivity of SrTiO3 was discussed in detail to illustrate how the reconfigurability with thermal transformation is generated.The numerical results show that the tunable broadband of the absorbent band has reached 90 GHz and the corresponding absorptivity is above 99% when the temperature increases from 280 K to 360 K.The resonance frequency will produce a blue-shift with the increase of the temperature.This paper presents a passive thermal-tunable metamaterial as a potential candidate for sensing,materials detection and frequency selective thermal emitters.展开更多
Plantains （Musa paradisiaca L.） are a major food staple in West Africa and are cooked in various forms. The objective of this work was to evaluate the frying characteristics of plantains at different stages of ripen...Plantains （Musa paradisiaca L.） are a major food staple in West Africa and are cooked in various forms. The objective of this work was to evaluate the frying characteristics of plantains at different stages of ripening. The plantains used in the study were at the unripe stage through four different ripening stages. The samples were peeled and sliced into 2 mm thickness and blanched in hot water at 70 ℃ for 3 min. The slices were then deep flied in canola oil at 180 ℃. The result showed that ripening stage significantly affected moisture loss and fat absorption profiles of the plantain chips. Fully ripened plantain absorbed up to 34% （db） oil during 4 min frying, much higher than unripe plantain. The oil uptake and moisture loss during frying of the plantain chip samples were modelled using 1st order kinetics. The kinetic parameters including rates of moisture loss and oil uptake varied according to the different stages of ripening. Ripening had a significant effect on the colour lightness （L） of the chips. Similarly, the redness （a）, the yellowness （b） and textural characteristics were significantly affected by ripening stage.展开更多
A kind of functional graphene thin film metamaterial on a metal-plane separated by a thick dielectric layer is designed for terahertz(THz) absorbers.We investigate the properties of the graphene metamaterial with diff...A kind of functional graphene thin film metamaterial on a metal-plane separated by a thick dielectric layer is designed for terahertz(THz) absorbers.We investigate the properties of the graphene metamaterial with different interlayers in the 0–3 THz range.The simulation results show that the absorption rate reaches up to 99.9% at the frequency of 1.917 THz.Changing the period to 80 μm×18 μm can get a narrow-band high quality factor(Q) absorber.We present a novel theoretical interpretation based on the standing wave field theory,which shows that the coherent superposition of incident and reflection rays produces standing waves,and the field energy is localized inside the thick spacers and dissipates through the metal-planes.展开更多
基金funded by the Strategic Priority Research Program-Climate Change:Carbon Budget and Relevant Issues (Grant No. XDA05040200)the National High Techonology Research and Development Program of China (863 Program,Grant No. 2011AA12A104)
文摘Over the Asian continent,high aerosol loading is critical to ensure the high accuracy of CO_2 retrieval in the near infrared absorption band.Simulations were performed to explore the effect of light path modification by aerosol son the atmospheric CO_2 near infrared band(6140-6270 cm^(-1)).The Vector LInearized Discrete Ordinate Radiative Transfer(VLIDORT) model and the Line-By-Line Radiative Transfer Model(LBLRTM) were used for forward calculations.The U.S.standard atmosphere was used for atmospheric profiles.The results indicate that the aerosols caused similar effects to increases in CO_2 in the planetary boundary layer and became more significant with aerosol layer rising while aerosol optical depth was 0.1.This effect will cause an over estimation of the CO_2 mixing ratio in the retrieval process and an under estimation in the aerosol layer.The results also indicate that the effect of urban and industrial aerosols is smaller than that of non-absorbing and dust aerosols because of the nearly constant absorption properties in the near infrared band.
基金National Natural Science Foundation of China(No.U1637212)National Defense Pre-research Foundation of China(No.61404130402)+1 种基金Fund for“1331 Project”Key Subject Construction of Shanxi ProvinceFund for Key Laboratory(No.61428050104)。
文摘Thermosensitive strontium titanate(SrTiO3)as a ferroelectric crystal with great tunability in microwave and terahertz band shows unparalleled potential value.Utilizing the thermal electromagnetic tunability to achieve the intelligent manipulation,a thermal-tunable metamaterial with terahertz-band absorption based on SrTiO3 crystal was proposed in this paper.The absorbent metamaterial(AM)is formed by Floquet’s linear periodic arranged unit,which is composed of a metallic ground plane and embedded cross SrTiO3 material in rhombic metallic patch,and separated by FR-4 dielectric spacer.The broadband frequency tunability of AM was operated by changing the temperature.The permittivity of SrTiO3 was discussed in detail to illustrate how the reconfigurability with thermal transformation is generated.The numerical results show that the tunable broadband of the absorbent band has reached 90 GHz and the corresponding absorptivity is above 99% when the temperature increases from 280 K to 360 K.The resonance frequency will produce a blue-shift with the increase of the temperature.This paper presents a passive thermal-tunable metamaterial as a potential candidate for sensing,materials detection and frequency selective thermal emitters.
文摘Plantains （Musa paradisiaca L.） are a major food staple in West Africa and are cooked in various forms. The objective of this work was to evaluate the frying characteristics of plantains at different stages of ripening. The plantains used in the study were at the unripe stage through four different ripening stages. The samples were peeled and sliced into 2 mm thickness and blanched in hot water at 70 ℃ for 3 min. The slices were then deep flied in canola oil at 180 ℃. The result showed that ripening stage significantly affected moisture loss and fat absorption profiles of the plantain chips. Fully ripened plantain absorbed up to 34% （db） oil during 4 min frying, much higher than unripe plantain. The oil uptake and moisture loss during frying of the plantain chip samples were modelled using 1st order kinetics. The kinetic parameters including rates of moisture loss and oil uptake varied according to the different stages of ripening. Ripening had a significant effect on the colour lightness （L） of the chips. Similarly, the redness （a）, the yellowness （b） and textural characteristics were significantly affected by ripening stage.
基金supported by the National Natural Science Foundation of China(Nos.61205096 and 11364010)the Science Foundation of Education Department of Guangxi in China(No.200911LX17)
文摘A kind of functional graphene thin film metamaterial on a metal-plane separated by a thick dielectric layer is designed for terahertz(THz) absorbers.We investigate the properties of the graphene metamaterial with different interlayers in the 0–3 THz range.The simulation results show that the absorption rate reaches up to 99.9% at the frequency of 1.917 THz.Changing the period to 80 μm×18 μm can get a narrow-band high quality factor(Q) absorber.We present a novel theoretical interpretation based on the standing wave field theory,which shows that the coherent superposition of incident and reflection rays produces standing waves,and the field energy is localized inside the thick spacers and dissipates through the metal-planes.
