The quantum yield of photosystem II, determined by chlorophyll fluorescence and the quantum yield of CO2 uptake, determined from gas exchange, are two physiologically important measurements in clarifying the response to environmental stress. Both measurements, however, require an accurate assessment of leaf light absorption in the photosynthetically active radiation wavelength range (400–700 nm...

Porous silica optical antireflective (AR) coatings prepared by traditional sol-gel method have been extensively used for high power laser systems, but a serious drawback is that contamination existing in the high vacuum is easily absorbed by the disordered open pore structure, resulting in a fast decrease in transmittance. To improve the stability of transmittance in vacuum, a contamination-res...

To attain the optical precision necessary to precisely quantify fluorescent or colorimetric signals, analytical systems have typically included quality-controlled cuvettes, flow cells, or dual-beam reference systems. We describe a system where a fluorescence or transmittance signal is quantified in single, standard, 12-mm-diameter polystyrene test tubes. Tube-to-tube variation is minimized by r...

The purpose of this investigation was to examine the effect of filler particle size and shape as well as filler content on light transmittance characteristics and color of experimental composite resins. A mixture of 30 mol% Bis-GMA and 70 mol% TEGDMA was prepared as a base monomer and to which a photoinitiator (camphorquinone) and a co-initiator (N,N-dimethylaminoethyl methacrylate) were added....

The vibrant colors of many birds' eggs, particularly those that are blue to blue-green, are extraordinary in that they are striking traits present in hundreds of species that have nevertheless eluded evolutionary functional explanation. We propose that egg pigmentation mediates a trade-off between two routes by which solar radiation can harm bird embryos: transmittance through the eggshell and ...

This work introduces a new vision-based approach for estimating chlorophyll contents in a plant leaf using reflectance and transmittance as base parameters. Images of the top and underside of the leaf are captured. To estimate the base parameters (reflectance/transmittance), a novel optical arrangement is proposed. The chlorophyll content is then estimated by using linear regression where the i...

Samples from Hong Kong, China, were analyzed for organic carbon (OC), elemental carbon (EC), and total carbon (TC) by three thermal protocols (low-temperature IMPROVE and high-temperature STN and NIOSH) and two optical monitoring methods: reflectance and transmittance. Good agreement (+/-10%) for TC among the three protocols was observed for sample loadings of 1-55 microg m(-3). The two protoco...

Pulse oximeters are widely used for noninvasive monitoring of oxygen saturation in arterial blood hemoglobin. We present a transmittance pulse oximetry system based on near-infrared (NIR) laser diodes (750 and 850 nm) for monitoring oxygen saturation of arterial blood hemoglobin. The pulse oximetry system is made up of the optical sensor, sensor electronics, and processing block. Also, we show ...

1) the Malkmus band model based on HITRAN 92 database: HITRAN 96 and HITRAN 99 are now available with more accurate molecular line parameters. Also ATREM employs the multiplication rule to handle transmittance in spectral regions where multiple gas absorption is present. This results in less accurate transmittance calculation in these regions, e.g., at 2.0μm where both H2O and CO2 strongly abso...

We present the formulation, calibration and validation of a model to estimate photosynthetically active radiation (PAR) intercepted by olive (Olea europaea L.) canopies. The model calculates the PAR transmittance at any point located within the four central trees of the orchard. The spatial and time integration of this process allows calculation of PAR transmitted to the ground and, thus, the P...