- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Evolution of the infrared emissivity of Ni during thermal oxidation until oxide layer opacity
摘要： The mid-infrared (3–22 μm) emissivity of high-purity Ni has been studied in its pure state, during an isothermal oxidation in air at 730 °C and in the fully oxidized state. Measurements in pure Ni were performed in Ar between 200 and 800 °C and a change of slope in the temperature dependence of the total normal emissivity around its Curie temperature (354 °C) was observed. An oxidation process was carried out at 730 °C for 33 days, when the emissivity stopped evolving and the results were representative of NiO. During the ?rst stages, the emissivity evolved forming the usual interference patterns of semi-transparent ?lms. A mixture of oscillatory and monotonic behaviours of the emissivity as a function of wavelength and oxide layer thickness was found, which manifests as a non-trivial evolution of the total normal emissivity, di?erent than that reported in previous studies. Finally, the emissivity of NiO was measured from below its Néel temperature (252 °C) to 850 °C. It showed the typical shape of a ceramic material with an extra vibrational mode due to two-phonon processes and an additional absorption band around 5 μm in the antiferromagnetic phase produced by magnons. The temperature dependence of its total normal emissivity di?ers signi?cantly from that of a lightly oxidized nickel sample from the literature. Overall, the in?uence of the surface characteristics on the thermal radiative properties of oxidized Ni is thoroughly discussed and highlights the importance of accounting for all possible sources of infrared emissivity evolution in order to make accurate radiative heat transfer calculations.
关键词： Nickel oxide,Infrared emissivity,Radiometry,Radiative heat transfer,Magnetic phase transition,Nickel,Oxidation
更新于2025-09-23 15:23:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - 3Cat-4: Combined GNSS-R, L-Band Radiometer with RFI Mitigation, and AIS Receiver for a I-Unit Cubesat Based on Software Defined Radio
摘要： The 3Cat-4 mission aims to demonstrate the capabilities of nano-satellites plus the versatility of a Software Defined Radio for passive Earth Observation. Three different microwave payloads are integrated into a single unit CubeSat platform: a multi-constellation (GPS and Galileo) and a dual-band (L1 and L2) Global Navigation Satellite System-Reflectometer receiver, a total power radiometer including a novel Radio Frequency Interference (RFI) detection and mitigation technique, and an Automatic Identification System receiver for vessels tracking. Being able to validate these technologies in a CubeSat enables their fast adoption as hosted payloads or in more performing dedicated platforms in the future. This paper shows a novel approach for embedding multiple passive microwave payloads in a single platform.
关键词： GNSS-R,RFI,AIS,Nano-satellite,Radiometry,CubeSat
更新于2025-09-23 15:21:21
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Measurement setup for differential spectral responsivity of solar cells
摘要： We have developed a setup for measuring differential spectral responsivities of unifacial and bifacial solar cells under bias light conditions. The setup uses 30 high-brightness LEDs for generating a quasi-monochromatic light source covering the wavelength range 290–1300 nm. Halogen lamps are used to generate bias-lighting conditions up to the irradiance level of 1000 W/m2. The setup has been fully characterized for spectral irradiances and spatial uniformities of all light sources. Validation measurements carried out using a reference cell of 2 × 2 cm2 area from Fraunhofer ISE demonstrated an agreement better than 2% over the wavelength range of 425–940 nm, with an expanded uncertainty of 2.6%. In the UV and IR regions, the discrepancies are higher but still within estimated uncertainties. The setup is also tested in measuring spectral responsivities of large 15 × 15 cm2 bifacial solar cells. The associated problems are discussed.
关键词： Radiometry,Bifacial,Solar cell,Spectral responsivity,Electricity,Efficacy
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Quantifying the Relationship Between Higher Photovoltaic Module Efficiency and the Adoption of Distributed Solar
摘要： Some applications of data from the Clouds and the Earth’s Radiant Energy System (CERES) scanning radiometer require the use of the point response function (PRF), which describes the influence of radiance from each point on the measurement. A radiance source for the measurement of the PRF of the CERES instruments was built and installed into the Radiometric Calibration Facility, in which the CERES instruments have been calibrated. The design and application of the PRF source and the computation of the PRF from these measurements are described. In order to compare the PRF based on measurements with the theoretical PRF, it is necessary to account for the finite size of the beam from the source. The use of the PRF source and the analysis of the data are demonstrated by application to the FM-5 instrument. The measured results compare well with theory for the CERES instruments and are presented for FM-5.
关键词： Aqua,Terra,point spread function,radiometry,National Polar-orbiting Partnership (NPP),Earth radiation budget,point response function (PRF),calibration,Clouds and the Earth’s Radiation Energy System (CERES)
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - An analysis of Passivated emitter and rear contact (PERC) cell and module
摘要： A synergetic approach for the estimation of stable boundary layer height (SBLH) using lidar and microwave radiometer (MWR) data is presented. Vertical variance of the backscatter signal from a ceilometer is used as an indicator of the aerosol stratification in the nocturnal stable boundary layer. This hypothesis is supported by a statistical analysis over one month of observations. Thermodynamic information from the MWR-derived potential temperature is incorporated as coarse estimate of the SBLH. Data from the two instruments are adaptively assimilated by using an extended Kalman filter (EKF). A first test of the algorithm is performed by applying it to collocated Vaisala CT25K ceilometer and humidity and temperature profiler MWR data collected during the HD(CP)2 Observational Prototype Experiment (HOPE) campaign at Jülich, Germany. The application of the algorithm to different atmospheric scenarios reveals the superior performance of the EKF compared to a nonlinear least squares estimator, particularly in nonidealized conditions.
关键词： signal processing,Adaptive Kalman filtering,microwave radiometry,remote sensing,laser radar
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE International Conference on RFID Technology and Applications (RFID-TA) - Pisa, Italy (2019.9.25-2019.9.27)] 2019 IEEE International Conference on RFID Technology and Applications (RFID-TA) - A Waveguide Transmitarray Antenna for Near-field Millimeter-wave Sensing Applications
摘要： Miniaturized hyperspectral imaging sensors are becoming available to small unmanned airborne vehicle (UAV) platforms. Imaging concepts based on frame format offer an attractive alternative to conventional hyperspectral pushbroom scanners because they enable enhanced processing and interpretation potential by allowing for acquisition of the 3-D geometry of the object and multiple object views together with the hyperspectral reflectance signatures. The objective of this investigation was to study the performance of novel visible and near-infrared (VNIR) and short-wave infrared (SWIR) hyperspectral frame cameras based on a tunable Fabry–Pérot interferometer (FPI) in measuring a 3-D digital surface model and the surface moisture of a peat production area. UAV image blocks were captured with ground sample distances (GSDs) of 15, 9.5, and 2.5 cm with the SWIR, VNIR, and consumer RGB cameras, respectively. Georeferencing showed consistent behavior, with accuracy levels better than GSD for the FPI cameras. The best accuracy in moisture estimation was obtained when using the reflectance difference of the SWIR band at 1246 nm and of the VNIR band at 859 nm, which gave a root mean square error (rmse) of 5.21 pp (pp is the mass fraction in percentage points) and a normalized rmse of 7.61%. The results are encouraging, indicating that UAV-based remote sensing could significantly improve the efficiency and environmental safety aspects of peat production.
关键词： radiometry,image classification,geographic information system,spectroscopy,Calibration,geometry,stereo vision,remotely piloted aircraft,remote sensing
更新于2025-09-23 15:19:57
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Assessment with Controlled In-Situ Data of the Dependence of L-Band Radiometry on Sea-Ice Thickness
摘要： The European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) and the National Aeronautics and Space Administration (NASA) Soil Moisture Active Passive (SMAP) missions are providing brightness temperature measurements at 1.4 GHz (L-band) for about 10 and 4 years respectively. One of the new areas of geophysical exploitation of L-band radiometry is on thin (i.e., less than 1 m) Sea Ice Thickness (SIT), for which theoretical and empirical retrieval methods have been proposed. However, a comprehensive validation of SIT products has been hindered by the lack of suitable ground truth. The in-situ SIT datasets most commonly used for validation are affected by one important limitation: They are available mainly during late winter and spring months, when sea ice is fully developed and the thickness probability density function is wider than for autumn ice and less representative at the satellite spatial resolution. Using Upward Looking Sonar (ULS) data from the Woods Hole Oceanographic Institution (WHOI), acquired all year round, permits overcoming the mentioned limitation, thus improving the characterization of the L-band brightness temperature response to changes in thin SIT. State-of-the-art satellite SIT products and the Cumulative Freezing Degree Days (CFDD) model are veri?ed against the ULS ground truth. The results show that the L-band SIT can be meaningfully retrieved up to 0.6 m, although the signal starts to saturate at 0.3 m. In contrast, despite the simplicity of the CFDD model, its predicted SIT values correlate very well with the ULS in-situ data during the sea ice growth season. The comparison between the CFDD SIT and the current L-band SIT products shows that both the sea ice concentration and the season are fundamental factors in?uencing the quality of the thickness retrieval from L-band satellites.
关键词： sea ice thickness,retrieval model validation,upward looking sonar,Arctic,Soil Moisture Active Passive (SMAP),Soil Moisture and Ocean Salinity (SMOS) mission,L-band radiometry
更新于2025-09-23 15:19:57
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An Optical Fiber Immunosensor with a Low Detection Limit Based on Plasmon Coupling Enhancement
摘要： Miniaturized hyperspectral imaging sensors are becoming available to small unmanned airborne vehicle (UAV) platforms. Imaging concepts based on frame format offer an attractive alternative to conventional hyperspectral pushbroom scanners because they enable enhanced processing and interpretation potential by allowing for acquisition of the 3-D geometry of the object and multiple object views together with the hyperspectral reflectance signatures. The objective of this investigation was to study the performance of novel visible and near-infrared (VNIR) and short-wave infrared (SWIR) hyperspectral frame cameras based on a tunable Fabry–Pérot interferometer (FPI) in measuring a 3-D digital surface model and the surface moisture of a peat production area. UAV image blocks were captured with ground sample distances (GSDs) of 15, 9.5, and 2.5 cm with the SWIR, VNIR, and consumer RGB cameras, respectively. Georeferencing showed consistent behavior, with accuracy levels better than GSD for the FPI cameras. The best accuracy in moisture estimation was obtained when using the reflectance difference of the SWIR band at 1246 nm and of the VNIR band at 859 nm, which gave a root mean square error (rmse) of 5.21 pp (pp is the mass fraction in percentage points) and a normalized rmse of 7.61%. The results are encouraging, indicating that UAV-based remote sensing could significantly improve the efficiency and environmental safety aspects of peat production.
关键词： Calibration,radiometry,geometry,image classification,stereo vision,remote sensing,remotely piloted aircraft,spectroscopy,geographic information system
更新于2025-09-23 15:19:57
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Sentinel-2 Level-L Radiometry Validation Using Vicarious Methods from Dimitri Database
摘要： Sentinel-2 is an Earth Observation optical mission developed and operated by the European Space Agency (ESA) in the frame of the Copernicus program of the European Commission. The mission consists on a MultiSpectral Instruments (MSI) on board a constellation of two satellites flying on the same orbit but phased at 180°: Sentinel-2A launched in June 2015 and Sentinel-2B launched in March 2017. It covers the Earth’s land surfaces and inland and coastal waters every five days at the equator under the same viewing conditions with high spatial resolution and wide field of view. Accurate radiometric calibration is key to the success of the mission; therefore, in-orbit calibration and validation activities are conducted within the Sentinel-2 Mission Performance Centre (MPC), including a consortium of Expert Support Laboratories (ESL). The Database of Imaging Multispectral Instrument and Tool for Radiometric Intercomparison (DIMITRI) is used to perform the vicarious validation of Level-1 products delivered to users. The aims of this validation are 1) to assess the quality of the data product at Level-1, 2) to monitor the evolution of the radiometry of both instruments and 3) to ensure that the products meet the mission requirement accuracy. Three vicarious methods are used, such as Rayleigh scattering, Desert Pseudo-Invariant Calibration Sites (PICS) and Sensor-to-Sensor inter-calibration methods. Although the results indicate good stability and performance of both sensors MSI-A/B, a slight discrepancy between them of ~1% over desert sites could be observed. Slight decrease of band B8A (865 nm) signal over Algeria-3 site has been detected since April 2017. This effect seems to be related to the impact of human and industry activities near the area. Radiometric performances and image quality of Sentinel-2 MSI-A/B level-1C products appear stable and meet the mission requirements.
关键词： Multispectral Instrument,validation,vicarious calibration methods,Remote sensing,Radiometry
更新于2025-09-19 17:15:36
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Robust GaN Limiting LNA for C-Ku Band T/R Modules
摘要： A synergetic approach for the estimation of stable boundary layer height (SBLH) using lidar and microwave radiometer (MWR) data is presented. Vertical variance of the backscatter signal from a ceilometer is used as an indicator of the aerosol stratification in the nocturnal stable boundary layer. This hypothesis is supported by a statistical analysis over one month of observations. Thermodynamic information from the MWR-derived potential temperature is incorporated as coarse estimate of the SBLH. Data from the two instruments are adaptively assimilated by using an extended Kalman filter (EKF). A first test of the algorithm is performed by applying it to collocated Vaisala CT25K ceilometer and humidity and temperature profiler MWR data collected during the HD(CP)2 Observational Prototype Experiment (HOPE) campaign at Jülich, Germany. The application of the algorithm to different atmospheric scenarios reveals the superior performance of the EKF compared to a nonlinear least squares estimator, particularly in nonidealized conditions.
关键词： microwave radiometry,laser radar,remote sensing,Adaptive Kalman filtering,signal processing
更新于2025-09-19 17:13:59