Transmittance glasses

Glasses 7905, 7910, 7911, 7912, 7913, and 7917 foi special uv and k applications. Glass 1720 is available with improved uv transmittance (designated glass 9730). Glass 7760 is also available with special transmission suitable for sunlamps. 

Fig. 3. Visible-light transmittance of automotive laminate A, 475-mm monolithic glass B, 5-mm laminated glass.

More objective laboratory methods employ a mechanical device such as a Terg-O-Tometer (110). Food soils are appHed to microscope sHdes or glass tape rather than to actual plates. The soils are tagged with fluorescent materials or with dark pigment to faciUtate measurement of residual soil. Reflectance or transmittance may also be read directly (111). 

FIG. 19 Light transmittance ( = 650 mm) of alternating mnltUayer of particles lb and 2 vs. number of deposited particle layers. (+) or (—) indicate that positively or negatively charged particles, respectively, were deposited in the last adsorption step (substrate glass modified with 3-AMDS and subsequently acidified). (From Ref. 156.)... 

For four years, Muller synthesized his own compounds and almost single-handedly screened them for their effect on houseflies. They were known to be transmitters of intestinal diseases like dysentery, and it was speculated at the time that they might spread polio. Muller built a cubic-meter glass chamber for insects and sprayed compound after compound at them. As soon as one compound seemed promising, he searched more carefully among its close relatives, using the natural insecticides, rotenone and pyrethrum, as controls. 

Interference filters consist of several evaporated dielectric layers on a glass or quartz substrate. Their transmittance can be tailored by choosing appropriate layers. A problem is their limited bandwidth of transmission which is usually above AT. = 30 nm. Also, a substantial loss in sensitivity has to be accepted since the maximum transmission is limited to less than 40%. 

The entrance window is a relevant part of the sensor. Common glasses as well as most transparent plastics block UV radiation. Standard UV-transmitting materials like quartz and sapphire are expensive. For UVA and to some extent the UVB special glasses but also plastics like some PMMA-derivatives or some silicon gels are available with a reasonable transmittance down to about 330 nm. For UVC applications with the important 254 nm line of Hg, quartz remains the standard solution. 

Figure 4.3 Transmission benefit of porous Si02 antireflection layer. The solar transmittance of a glass sheet increases from 90 to 95%. (Reproduced from Merck.com)...

Amorphous PET is transparent with light transmittance ranging from 80% up to 92%, haze of roughly 0.3-1.3% and a refractive index of about 1.575. Glass Polymers are specially designed to mimic thick glass for packaging cosmetics and healthcare products. 

The procedures for recording spectra of heteronuclei often differ considerably from those for H and (which would today be considered routine ) since it is necessary, even for routine measurements, to adjust the experimental conditions to suit the special properties of the nuclei to be observed. For example, the spin-lattice relaxation times for some nuclides, such as N, are very long, whereas for others (especially those with an electric quadrupole moment, such as N) they are very short. Also, the spectra observed for some nuclides contain interfering signals caused by other materials present, for example the glass of the sample tube ("B, Si), the spectrometer probe unit ( Al) or the transmitter/receiver coil. For many nuclides the sample temperature and its constancy are important factors for example, quadrupolar nuclides such as O give narrower signals when the temperature is increased. 

The transmittance spectrum of a titania nanotube-film (transparent) on glass is shown in Fig. 5.33. The optical behavior of the Ti02 nanotube-arrays is quite similar to that reported for mesostructured titanium dioxide [133], The difference in the envelope-magnitude encompassing the interference fringe maxima and minima is relatively small compared to that observed in titania films deposited by rf sputtering, e-beam and sol-gel methods [134],... 

Fig. 5.33 Transmittance spectra of glass (Corning 2947) substrate, and 450°C aimealed nanotubular titania film atop same glass (Corning 2947) substrate.

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