Wavelength visible

The success of separation of colored compounds is usually monitored visually. Such compounds absorb a particular portion of the polychromatic (white) light in the visible wavelength range. The remaining radiation (complementary radiation) is reflected and detected by the eye it determines the color of the substance zone. Table 1 correlates the wavelengths, colors and complementary colors. 

Although a clear objechve, extreme AO at visible wavelength will certainly require more technology development, delaying its implementation to later stages. MOEMS (Micro-Opto-Electronical Mechanical devices) constitute a promising avenue, however not the only one (see Ch. 10). Piezo-stacks, combined with thin shells and moderate segmentahon in a pupil, may offer a more conservahve baseline. 

The goal of the polychromatic LGS (PEGS) is to provide us with a 100% sky coverage, down to visible wavelengths. Its basic principle relies on the chromatic property of the air refraction index n (Fig. 18). 

The absorption and fluorescence spectra of a neat film made of RdB-den-drimer are shown in Fig. 2. The absorption spectrum in visible-wavelength region was similar to that obtained from a solution of RdB with a concentration less than 0.1 mmol/1. Interpretation of the fluorescence in terms of the Frank-Condon mechanism indicated that the core RdB chromophore behaved with a site-isolation effect and had little interaction with the neighboring chro-... 

In terms of their optical properties, all solids fall into one of two classes. Either they are transparent to light (here we are restricting the term "light" to visible radiation) or they are opaque. In the latter case, all of the radiation may be reflected. However, most solids reflect some wavelengths and absorb others. This is the condition that we call "color". If all visible wavelengths are absorbed, the solid is said to be "black" while reflectance of all visible wavelengths results in a "white" solid. We intend to show how "color" is measured but first must define the nature of "light". 

Visible wavelength spectrophotometry Mass selective detection Nitrogen-phosphorus detection Electron capture detection UV detection... 

The recognition of the importance of MP in maintaining the health of the retina has led to the development of a number of methods for determining its concentration in situ. These methods, necessarily noninvasive, are routinely employed in dietary supplementation studies with lutein or zeaxanthin to monitor the uptake of the carotenoids into the retina. Every method exploits the optical properties of lutein and zeaxanthin, specifically their absorbance at visible wavelengths. The detection of a light signal, modified by the carotenoids, is accomplished either by the retinal photoreceptors themselves (psychophysical methods) or by a physical detector such as a photomultiplier,... 

Because it is the UV-B radiation (280-320 nm) that causes the degradation, the absorption spectra of the UV-absorber must coincide with these wavelengths. UV-A (320-400 nm) does not cause damage (it is not energetic enough) and UV-C (wavelength less than 280 nm) does not reach the troposphere (it is filtered out by ozone in the stratosphere). The problem is to find an additive that absorbs UV-B but does not have an absorption "tail" in the UV-A and visible wavelengths, and therefore would have a yellow appearance. 

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