High-reflection surfaces

Laminated glass is used for solar control, particularly where a highly reflective surface is not desired and where the laminate contributes other benefits. In these applications, a uniformly pigmented interlayer is obtained from the manufacturer and the laminate can be prepared by the conventional process. Broad ranges of colors and transmission levels are available with shading coefficients as low as 0.41. Pigmented interlayer is considered to be more... 

Calculate the beating due to solar radiation on the flat concrete roof of a building, 8 nr by 9 m. if the surface temperature of the roof is 330 K. What would be the effect of covering the roof with a highly reflecting surface such as polished aluminium ... 

Ability to see highly reflective surfaces in bright light... 

Near infra-red 0 to 90 By surface measurement. Highly reflective surfaces, crystalline materials and very dark coloured materials can cause difficulty. 

The hard, glaring, and highly reflective surfaces of polished terrazzo floors, glazed-tile walls, and white ceiling tiles ere-... 

NIR spectra are acquired using dried tissue, either whole or ground. The reflectance is measured relative to a so-called white reference, which is a highly reflective surface, such as Gore-Tex or white ceramic. Near-infrared reflectance spectra, or absorbance spectra, defined as log(l/R), with R being the reflectance, look rather flat. For analysis purposes the second derivative of the spectra is often used, because it enhances certain spectral features. 

The reflection coefficient of a fully burnished film was found to be the same as that of the MoSj (001) plane and their reflectivities were also the same. They therefore concluded that the surface of the film consisted of an assembly of (001) basal planes. They also inferred that a highly reflective surface occurs when the coefficient of friction is a minimum. 

Gamulya and co-workers also concluded on the basis of electron microscopy and micro-electron diffraction that the production of a highly reflective surface occurs when the coefficient of friction reaches a minimum level. The full orientation appears to be limited to a very thin surface layer, which they found to be about 0.1 tjm thick in their tests, while Brudnyi and Karmadonov described it as being only one crystal thick, regardless of the force used for burnishing. On the other hand, a fully densified, fully-oriented layer without discontinuities may not be distinguishable in practice from an extended single crystal. 

The VMPs (vacuum metallized pigments) differ very much from these traditional pigment flakes. Due to the original PVD-process, they are extremely thin (ca. 0.03 pm) and provide a very smooth, highly reflective surface. The particle shape has a tremendous influence on the metallic effect (see below). 

Highly reflective, surface-metallized, flexible polyimide films containing silver are accessible by the incorporation of [Ag(hfac)] into poly(amic acid) solutions followed by thermal curing to 300 "C . The silvered films are thermally stable and maintain mechanical properties similar to those of the parent polyamide. 

Gloss paints or enamels dry to a highly reflecting surface. 

If a highly reflective surface is required, should one use a material with a high or low index of refraction Explain. 

The problem of reflections is most critical if highly reflective surfaces are involved. Optical elements to be considered are interference filters, reflective ND filters, and photomultiplier cathodes. Problems can occur by backreflection of excitation light into the sample, and by multiple reflection in the detection path. 

Fig. 7.24 Reflections from a highly reflective surface hack into the sample...

Fig. 7.25 Reflections between two highly reflective surfaces left) and between a highly...

The bandwidth can be further decreased by using two interference filters in series. However, it is preferable to construct a double filter that consists of three highly-reflecting surfaces, separated by two nonabsorbing layers of the same optical thickness. If the thickness of these two layers is made slightly different, a bandpass filter that has a flat transmission curve but steep slopes to both sides results. Commercial interference filters are currently available with a peak transmission of at least 90% and a bandwidth of less than 2 nm [4.46,4.52], Special narrow-band filters even reach 0.3 nm, however, with reduced peak transmission. 

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