New spectral transmittance models for nanofluids and their application in energy-efficient windows

In situ fabrication of ZnO nanorods/Ag hybrid film with high mid-infrared reflectance for applications in energy efficient windows

Reflectance modulation of transparent multilayer thin films for energy efficient window applications

Effects of Oxygen Flow on the Infrared Switching Properties of Vanadium Oxide Thin Films

Fabrication of multifunctional coating with high luminous transmittance, self-cleaning and radiative cooling performances for energy-efficient windows

Optical description of HfO2/Al/HfO2 multilayer thin film devices

Transparent phase change hydrogel for energy-efficient thermal regulation in window applications

A novel bidirectional fast self-responsive PVA-PNIPAM/LimCsnWO3 composite hydrogel for smart window applications

Dual-intelligent windows regulating both solar and long-wave radiations dynamically

We propose a spectral prediction model for predicting the reflectance and transmittance of recto-verso halftone prints. A recto-verso halftone print is modeled as a diffusing substrate surrounded by two inked interfaces in contact with air (or with another medium). The interaction of light with the print comprises three components: (a) the attenuation of the incident light penetrating the print across the inked interface, (b) the internal reflectance and internal transmittance that accounts for the substrate's intrinsic reflectance and transmittance and for the multiple Fresnel internal reflections at the inked interfaces, and (c) the attenuation of light exiting the print across the inked interfaces. Both the classical Williams-Clapper and Clapper-Yule spectral prediction models are special cases of the proposed recto-verso reflectance and transmittance model. We also extend the Kubelka-Munk model to predict the reflectance and transmittance of recto-verso halftone prints. The extended Kubelka-Munk model is compatible with the proposed recto-verso reflectance and transmittance model. In the case of a homogeneous substrate, the recto-verso model's internal reflectance and transmittance can be expressed as a function Kubelka-Munk's scattering and absorption parameters, or the Kubelka-Munk's scattering and absorption parameters can be inferred from the recto-verso model's internal reflectance and transmittance, deduced from spectral measurements. The proposed model offers new perspectives both for spectral transmission and reflection predictions and for characterizing the properties of printed diffuse substrates.

In this paper spectral reflectance and transmission of a low-coherence fiber-optic Fabry-Perot interferometer with thin ZnO layers is analyzed using a multi-cavity approach. In the investigated setup two standard single-mode optical fibers (SMF-28) with thin ZnO films deposited on their end-faces form an extrinsic Fabry-Perot interferometer with air cavity. Calculations of the spectral response of the interferometer were performed for different thickness of the layers (50, 100, 150, 200 nm). Based on the obtained results, it can be concluded that the use of ZnO thin films improves the reflectance of the interferometer. Moreover, addition of another cavity can make it possible to perform sensing of two different quantities (e.g. temperature and refractive index). The optimal lengths of the Fabry-Perot cavities were selected using the results of modelling for achieving the best performance in a sensing application.

This work presents Land Surface Temperature (LST) retrieval from Landsat-8 data using the Generalized Split-Window (GSW) algorithm. First, radiative transfer modeling experiments were conducted using the moderate spectral resolution atmospheric transmittance algorithm and computer model (MODTRAN) 4.0 fed with SeeBor V5.0 atmospheric profile database to simulate the brightness temperatures in Thermal InfraRed Sensor (TIRS) bands 10 (centered at 10.9 μm) and 11 (centered at 12.0 μm) related to Land Surface Emissivities (LSEs) and Total Precipitable Water (TPW). Then, the unknown coefficients of the GSW algorithm were obtained through multi-variable regressions, in which the simulated data were grouped into several subranges to improve fitting accuracy. Next, LSTs were derived from the clear-sky TIRS/Landsat-8 data in 2015, where LSEs were estimated from Operational Land Imager (OLI) measurements using the Normalized Difference Vegetation Index (NDVI) Based Emissivity Method (NBEM), and TPWs were extracted from the European Centre for Medium-range Weather Forecasts (ECMWF) reanalysis data. Finally, the derived LSTs were validated with MOD11_L2 V5 product. The results show that the GSW algorithm developed in this work can accurately retrieve LST from the Landsat-8 data, and the relative error is 0.18±0.68 K against the MOD11_L2 V5 product.

The Advanced Hyper-spectral Imager (AHSI) data on-board GF-5 satellite fills up China's lack of hyper-spectral earth observation technology. However, using GF-5 AHSI data for remote sensing applications, especially quantitative remote sensing applications, a challenging problem is to retrieve surface reflectance through atmospheric correction. In this paper, the MODerate spectral resolution atmospheric TRANsmittance algorithm and computer model (MODTRAN) radiative transfer model was used to perform atmospheric correction experiments (AHSI-AC) for GF-5 AHSI data. And we validated the atmospheric correction results based on measured surface reflectance and Landsat 8 surface reflectance data. Using field-measure spectra for validation the AHSI-AC method has a relative error of about 10% in most bands. Compared with the ENVI-FLAASH algorithm, the accuracy of the blue-green bands and the short-wave infrared bands are significantly improved, and the red and near-infrared bands are similar. Using Landsat 8 data for intercomparison, the large homogeneous, non-vegetated pixels were selected, and the overall accuracy of the 515 selected validation points reached 81.7%.

Fluorescent brighteners in paper can emit visible blue lights or fluorescence after absorbing invisible UV (ultraviolet) lights and the visible blue lights can increase the whiteness of the paper in the visual effects. In this paper, we use the enhanced Clapper-Yule model to establish a new predicted reflectance model for halftone image. The reflective law of halftone image on fluorescent supports is generalized by utilizing the idea that the reflected light by fluorescent supports is divided into two parts: the primary streams which consist of originally incident light and the fluorescent streams which are created by absorption of the UV lights. Firstly, the spectral reflectance of the vacant fluorescent supports and ink layer on fluorescent supports are analyzed. Secondly, the reflectance and transmittance of ink layer on fluorescent supports are studied. Then the physical dot gain that results from the real extension of an ink dot (i.e., ink spreading) is studied. Finally, we establish a reflection and transmission model for a halftone image on paper with fluorescent additives. To prove the accuracy of the model, we make data simulation with Matlab software and two reflectance curves (the reflectance of halftone image on paper with and without fluorescent additives) were generated. From the results, we can make a conclusion that the new model has a good accuracy to predict the reflectance of halftone image on fluorescent supports.

The far infrared continuum absorption of water vapour

Effect of fluorine and niobium co-doping on boosting the NIR blocking performance of TiO2 nanoparticles for energy efficient window