Search results for " Reflection"
showing 10 items of 345 documents
Improved Temperature and Emissivity Separation Algorithm for Multispectral and Hyperspectral Sensors
2017
The Temperature and Emissivity Separation (TES) algorithm was originally developed for the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). This paper focuses on improving the TES algorithm. The main modification is the replacement of the normalized emissivity module with a new module, which is based on the smoothing of spectral radiance signatures. Smoothing is performed by estimating emissivity using an optimized approximation of the relationship between brightness temperature and emissivity. The improved TES algorithm, which is called Optimized Smoothing for Temperature Emissivity Separation (OSTES), was first tested on simulated data from three different sensors, …
Wavelength-selective directional coupling with dielectric-loaded plasmonic waveguides
2009
International audience; We consider wavelength-selective splitting of radiation using directional couplers (DCs) formed by dielectric-loaded surface-plasmon-polariton waveguides (DLSPPWs). The DCs were fabricated by depositing subwavelength-sized polymer ridges on a gold film using large-scale UV photolithography and characterized at telecommunications wavelengths with near-field microscopy. We demonstrate a DLSPPW-based 45-mu m-long DC comprising 3 mu m offset S bends and 25-mu m-long parallel waveguides that changes from the "through" state at 1500 nm to 3 dB splitting at 1600 nm, and show that a 50.5-mu m-long DC should enable complete separation of the radiation channels at 1400 and 162…
Determination of in vivo skin moisture level by near-infrared reflectance spectroscopy
2015
Near-infrared spectroscopy has a potential for noninvasive determination of skin moisture level due to high water absorption. In this study, diffuse reflectance spectra of in vivo skin were acquired in the spectral range of 900 nm to 1700 nm by using near-infrared spectrometer, optical fiber and halogen bulb light source. Absorption changes after applying skin moisturizers were analyzed over time at different body sites. Results show difference in absorption when comparing dry and normal skin. Comparison of absorption changes over time after applying moisturizer at different body sites is analyzed and discussed. Some patterns of how skin reacts to different skin moisturizers are shown, alth…
Core-clad phosphate glass fibers for biosensing
2019
Recently, a phosphate glass with composition 20 CaO-20 SrO-10 Na2O-50 P2O5 (mol%) was found to have good potential as a biomaterial and to possess thermal properties suitable for fiber drawing. This study opened the path towards the development of fully bioresorbable fibers promising for biosensing. In the past, this phosphate glass with CeO2 was found to increase the refractive index and the glass stability. Therefore, a new SrO-containing glass was prepared with 1 mol% of CeO2 and core fibers were drawn from it. A core-clad fiber was also processed, where the core was a Ce-doped glass and the clad undoped, to allow for total internal reflection. The mechanical properties of the core and c…
MCM-41-CdS nanoparticle composite material: Preparation and characterization
2010
The preparation and characterization of a hierarchical material constituted by a mesoporous silica MCM-41 whose mesochannels contain CdS nanoparticles capped with both bis(2-ethylhexyl) amine and bis(2-ethylhexyl) sodium sulfosuccinate is reported. MCM-41 powder was synthesized by using the LCT methodology. CdS nanoparticles were obtained within the inversed micelle core of a water/ AOT/n-heptane microemulsion. Nanoparticles growth was followed by means of UV–Vis spectroscopy and was inhibited by BEA addition. The CdS-capped nanoparticles were separated by centrifugation, washed with water and ethanol and finally dispersed in n-heptane. The insertion of CdS nanoparticles into MCM-41 mesocha…
Strukturelle Veränderungen in säuregeätztem Schmelz im konfokalen Laser-Scanning-Mikroskop
1996
The aim of the present investigation was to elucidate structural alternations in enamel subjected to acid etch technique and treatment under remineralizing conditions by means of a new microscopy technique known as confocal laser scanning microscopy (CLSM). Blocks of enamel were treated with 37% phosphoric acid and exposed for 3 weeks to an oral environment. Tomographic CLSM images were subsequently obtained and compared with controls. CLSM proved to be a reliable, highly reproducible and simple method of qualitative assessment of structural changes occurring on the surface of enamel and in areas below the surface as deep as 100 microns or more. Structural alterations associated with acid a…
Formation and Growth of Pd Nanoparticles Inside a Highly Cross-Linked Polystyrene Support: Role of the Reducing Agent
2014
Simultaneous time-resolved SAXS and XANES techniques were employed to follow in situ the formation of Pd nanoparticles in a porous polystyrene support, using palladium acetate as a precursor and gaseous H2 or CO as reducing agents. These results, in conjunction with data obtained by diffuse reflectance UV–vis and DRIFT spectroscopy and TEM measurements, allowed unraveling of the different roles played by gaseous H2 and CO in the formation of the Pd nanoparticles. In particular, it was found that the reducing agent affects (i) the reduction rate (which is faster in the presence of CO) and (ii) the properties of the hosted nanoparticles, in terms of size (bigger with CO), morphology (spherica…
A Simple “Plastic Bag” Technique for Visible Spectra of Solid Metal Complexes
1979
The techniques commonly used to study the visible spectra of transition metal complexes in the solid state involve diffuse reflectance from the powdered sample or transmission through a mull of the compound in mineral oil on filter paper. Pressed KBr (for anhydrous compounds) and AgCl (for compounds containing water or other highly polar ligands) disk techniques have been used even for low temperature spectra. All of the transmission techniques mentioned are based on mixing the sample with another compound which may induce changes in the compound under study via chemical reactions. Air- and water-sensitive complexes also need special care. These interferences may be reduced by the use of th…
Effect of hydraulic coefficient on membrane performance for rejection of emerging contaminants
2018
International audience; The efficient removal of Endocrine Disruptive Chemicals (EDCs) namely oxybenzone and atrazine using polysulfone (PSf) composite membranes is reported in this article. A negatively charged hydrophilic mixed matrix membrane was prepared by using Polyaniline modified halloysite nanotubes (PANi-HNT) and polysulfone. The X-ray diffraction (XRD) and attenuated total reflectance infrared (ATR-IR) technique confirm the conversion of Halloysite nanotubes to Polyaniline modified halloysite nanotubes and their presence in membrane matrix. The microvoids observable in the SEM images depict the internal structure of the membrane. Further, increasing in the water uptake and decrea…
Spin polarization of magnetoresistive materials by point contact spectroscopy
2003
In the strive to find a straightforward method for determining the spin polarization, the analysis of the Andreev reflection process in point contact junctions has attracted much interest. However, the prerequisite for anevaluation of the transport spin polarization in this scheme is the existence of elastic (ballistic or diffusive) transport, which cannot be assumed a priori. We therefore also include inelastic processes in our analysis and exemplify that thermal effects can have a significant effect on data evaluation. As ferromagnetic samples with a predicted half metallic behavior and comparably low conductivity we used thin films of the double perovskite Sr 2 FeMoO 6 and bulk material …