A study on the variation of the spectral bidirectional reflectance distribution function (BRDF) of four diffuse reflectance standards (matte ceramic, BaSO(4), Spectralon, and white Russian opal glass) is accomplished through this work. Spectral BRDF measurements were carried out and, using principal components analysis, its spectral and geometrical variation respect to a reference geometry was assessed from the experimental data. Several descriptors were defined in order to compare the spectral BRDF variation of the four materials.
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http://dx.doi.org/10.1364/AO.51.008535 | DOI Listing |
Small Methods
January 2025
Institute of Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1, Zürich, 8093, Switzerland.
In situ monitoring is essential for catalytic process design, offering real-time insights into active structures and reactive intermediates. Electron paramagnetic resonance (EPR) spectroscopy excels at probing geometric and electronic properties of paramagnetic species during reactions. Yet, state-of-the-art liquid-phase EPR methods, like flat cells, require custom resonators, consume large amounts of reagents, and are unsuited for tracking initial kinetics or use with solid catalysts.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China.
We have observed the Berry phase effect associated with interband coherence in topological surface states (TSSs) using two-color high-harmonic spectroscopy. This Berry phase accumulates along the evolution path of strong field-driven electron-hole quasiparticles in electronic bands with strong spin-orbit coupling. By introducing a secondary weak field, we perturb the evolution of Dirac fermions in TSSs and thus provide access to the Berry phase.
View Article and Find Full Text PDF3D Print Addit Manuf
December 2024
Photo-Acoustics Research Laboratory, Department of Mechanical and Aerospace Engineering, Clarkson University, Potsdam, New York, USA.
Unlike many conventional manufacturing techniques, 3D Printing/Additive Manufacturing (3DP/AM) fabrication creates builds with unprecedented degrees of structural and geometrical complexities. However, uncertainties in 3DP/AM processes and material attributes could cause geometric and structural quality issues in resulting builds and products. Evaluating the sensitivity of process parameters and material properties for process optimization, quality assessment, and closed-loop control is crucial in practice.
View Article and Find Full Text PDFAppl Radiat Isot
December 2024
Istinye University, Istanbul, 34010, TR, Turkey. Electronic address:
The intrinsic radiation spectra of LYSO scintillators are investigated through detailed GEANT4 and SimSiPM simulations, focusing on how changes in configuration and size influence the radiation characteristics. Using these simulation packages together, a comprehensive simulation of the physical processes as well as a detailed simulation of the photodetector response, including factors such as dark count rate, optical crosstalk, afterpulse, noise, and saturation effects, was performed. The results of the simulations indicate that the primary factor affecting the intrinsic radiation pattern is the total volume of the crystal, rather than surface treatments or minor geometric variations.
View Article and Find Full Text PDFTalanta
December 2024
State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, 030006, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China.
The combined application of near-infrared spectroscopy (NIRS) and X-ray fluorescence spectroscopy (XRF) has achieved remarkable results in coal quality analysis by leveraging NIRS's sensitivity to organic compounds and XRF's reliability for inorganic composition. However, variations in particle size distribution negatively affect the diffuse reflectance of NIRS and the fluorescence signal intensities of XRF, leading to decreased accuracy and repeatability in predictions. To address this issue, this study innovatively proposes a particle size correction method that integrates image processing and deep learning.
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