Other optical effects

In fact, most neon lamps are mercury lamps in which the inside of the tube is coated with a phosphor. To see if the lamp is truly neon-based, look at the bulb before it glows a real neon lamp needs no phosphor coating, so the glass is clear and without frosting.  

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Fraunhofer rules do not include the influence of refraction, reflection, polarization and other optical effects. Early Iziser particle analyzers used Fraunhofer approximations because the computers of that time could not handle the storage cuid memory requirements of the Mie method. For example, it has been found that the Fraunhofer-based instrumentation cannot be used to measure the particle size of a suspension of lactose (R.I. = 1.533) in iso-octane (R.I. = 1.391) because the relative refractive index is 1.10, i.e.- 1.533/1.391. This is due to the fact that diffraction of light passing through the particles is nearly the same as that passing around the particles, creating a combined interference pattern which is not indicative of the true... 

Most paint formulations consist of disperse systems (solid in liquid dispersions) [2]. The disperse phase consists of primary pigment particles (organic or inorganic) which provide the opacity, colour and other optical effects these are usually in the submicron range. Other coarse particles (mostly inorganic) are used in primers and undercoats to seal the substrate and enhance adhesion of the top coat The continuous phase consists of a solution of polymer or resin which provides the basis for a continuous film that seals the surface and protects it from the outside environment Most modem paints contain latexes which are used as film formers. These latexes - which typically have a glass transition temperature (Tg) below... 

Thus the absorbance is a measure of the surface concentration of R. The spectrum of absorbance is not the same as the conventional absorption spectrum (sr v. A), because Agff and 8 vary with A and because various other optical effects associated with the electrode/substrate system complicate the picture (6, 45, 46). 

Fraunhofer rules do not include the influence of refraction, reflection, polarization and other optical effects. Early laser particle analyzers used Fraunhofer approximations because the computers of that time could not handle the storage and memory requirements of the Mle method. 

The measurement of the free EuK signal is used as an internal control for the calculation of a 665/620 ratio. This ratio compensates for turbidity of the sample, absorption by colored compounds and other optical effects. The overall signal decreases as a result of these interferences, but the ratio does not change. This feature is essential for a homogeneous method where, by definition, all the assay components are present during the measurement. 

An external reference such as vapor bands observed in an intermediate focus in the optics can be used to correct for laser intensity and some of the instrumental throughput factors. In this approach, some reference external to the sample is used to correct for all intensity changes except those associated with the final optics and sample properties. It is crucial to note that they do not correct for changes in sample density, absorbance, or any of the other optical effects discussed earlier. 

Certain glass-ceramic materials also exhibit potentially useful electro-optic effects. These include glasses with microcrystaUites of Cd-sulfoselenides, which show a strong nonlinear response to an electric field (9), as well as glass-ceramics based on ferroelectric perovskite crystals such as niobates, titanates, or zkconates (10—12). Such crystals permit electric control of scattering and other optical properties. 

A wide variety of other nonlinear optical effects also have been demonstrated. According to equation 12, if two light beams having frequency CO and CO2 are combined in a material with a nonzero value of light waves of frequency + UJ2 and are produced. A combination of such effects, used... 

For example, the racemic thioester 57 was placed in contact with a certain optically active amide. After 28 days the solution contained 89% of one enantiomer and 11% of the other. To effect the deracemization two conditions are necessary (1) the enantiomers must complex differently with... 

The fact that the absorption spectrum of CdS changes when electrons are produced on it may be regarded as a non-linear optical effect, i.e. a dependence of the absorption coefficient on the light intensity. Other non-linear effects, which are caused... 

SHG, more so than other optical techniques, can give deceptive results due to propagation phenomena. Disregarding for the moment optical absorption effects, non-phase-matched SHG displays the behavior pictured in Figure 2 (18). The harmonic intensity I w emerging from a sample depends on the sample thickness / in a... 

J. M. Hammer, et al., Isolators, polarizers and other optical waveguide devices using a resonant-layer effect, Journal Lightwave Technology 22, 1754-1763 (2004). 

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