Optical properties transmittance

Zhang and coworkers (2004) studied the influence of the Ar gas flow rate on the properties of the deposited Ti02 films and found that the photocatalytic degradation of methyl orange was enhanced when the Ar flow rate increased, which was ascribed to the dependency of both the crystallite size of Ti()2 and the optical properties (transmittance and reflectance) of the films on the Ar flow rate. The... 

Improvements to the model have been made by Lawson et al. [44-46]. The improvements use estimates of thermal conductivity, specific heat and thermo-optical properties (transmittance, reflectance and absorptance) obtained from the thermal data collected from the testing of a variety of fabrics typically used in fire fighters protective clothing. A detailed mathematic model is developed to study transient heat and moisture transfer through multilayered fabric assemblies with or without air gaps. First principles are used to derive the governing equations for transient heat and moisture transfer. The equations also account for the effect of moisture on thermodynamic and transport properties. Numerical simulations are used to study heat and mass transfer. A software tool (Protective Clothing Performanee... 

Finally, values of sx are directly proportional to transmittance for indeterminate errors due to fluctuations in source intensity and for uncertainty in positioning the sample cell within the spectrometer. The latter is of particular importance since the optical properties of any sample cell are not uniform. As a result, repositioning the sample cell may lead to a change in the intensity of transmitted radiation. As shown by curve C in Figure 10.35, the effect of this source of indeterminate error is only important at low absorbances. This source of indeterminate errors is usually the limiting factor for high-quality UV/Vis spectrophotometers when the absorbance is relatively small. 

M. S. Patterson, B. Chance, and B. C. Wilson. Time resolved reflectance and transmittance for the non-invasive measurement of tissue optical properties. Applied Optics, 28(12) 2331-2336, 1989. 

Optical properties are not greatly affected by long outdoor exposures. For example, after three-years exposure in a sunny climate, the light transmittance of given grades is superior to 90%, and the yellowing and haze are slight. 

The optical properties of MPS3 and Li,MPS3 have been studied. The host phases are broad-band semiconductors with band gaps of 1.3-3.5 eV. The three compounds that are electrochemically active are NiPS3, FePS3 and FePSe3, which possess the smallest band gaps. Upon intercalation with lithium, the transmittance decreases until the... 

Photometric accuracy is determined by comparing the difference between the measured absorbance of the reference standard materials and the established standard value. Many solid and liquid standards are commonly used to verify the photometric accuracy of a spectrophotometer. An optically neutral material with little wavelength dependency for its transmittance/absorbance is desirable because it eliminates the spectral bandwidth dependency of measurements. The advantages and disadvantages of various commonly used photometric accuracy standards are summarized in Table 10.6. Even for a relatively stable reference standard, the intrinsic optical properties may change over time. Recertification at regular intervals is required to ensure that the certified values of the standards are meaningful and accurate for the intended use. 

An important advantage of the method is the elimination of the severe problems of handling and breakage of large sheets of costly glass that make up the cells. Cell-cast sheet has superior optical properties and light transmittance as well as smoother surfaces. The continuous process provides more uniform thickness and has less tendency to form warped sheet. 

Fig. 14. Examples of optical properties of materials (reflectance, transmittance) for window structures. When used in conjunction with solar spectral distributions, energy savings can be...

Several authors have addressed the determination of the optical properties of aqueous titanium dioxide suspensions in the context of photoreactor modeling (Brandi et al., 1999 Cabrera et al., 1996 Cured et al., 2002 Salaices et al., 2001, 2002 Satuf et al., 2005 Yokota et al., 1999). Among the determined properties are extinction, scattering, and absorption coefficients, as well as the asymmetry parameter of the scattering phase function. In general the procedures involve fitting of a radiative transfer model to the experimental results for reflectance and transmittance of radiation. 

The transmission spectra of ITO films as deposited and annealing are showed in Figure 1. All transmittance data of the samples at maximum (T jJ is listed in Table 1. A maximum transmission of about 99 % is achieved in the visible spectral region after annealing. The optical properties of ITO films are determined to a large extent by the microstructure of... 

Solution filters are readily prepared in any photochemical laboratory. Their compositions and optical properties are available throughout the literature.137,157 158 Figure 3.3 shows, for example, the transmission curve of a band-pass solution filter made of Cr(SC>4)2 dissolved in dilute aqueous H2SO4, which transmits radiation at 325 20 nm. As a result, the 313.9 nm band, available in the emission spectrum of medium-pressure mercury lamps, can be isolated. However, some of the reported solutions have limited photochemical stability and should be regularly checked for transmittance. 

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