Transmittance, optical

Fig. 16. Optical transmittance spectmm of a typical DNQ-novolac resist. ( ), The transmittance of a 1 p.m film after coating. (-), the transmittance of...

Other detection methods are based on optical transmittance [228-231], Alcohol sulfates have been determined by spectrophotometric titration with barium chloride in aqueous acetone at pH 3 and an indicator [232] or by titration with Septonex (carbethoxypentadecyltrimethylammonium bromide) and neutral red as indicator at pH 8.2-8.4 and 540 nm [233]. In a modified two-phase back-titration method, the anionic surfactant solution is treated with hyamine solution, methylene blue, and chloroform and then titrated with standard sodium dodecyl sulfate. The chloroform passing through a porous PTFE membrane is circulated through a spectrometer and the surfactant is analyzed by determining the absorbance at 655 nm [234]. The use of a stirred titration vessel combined with spectrophotometric measurement has also been suggested [235]. Alternative endpoint detections are based on physical methods, such as stalag-mometry [236] and nonfaradaic potentiometry [237]. 

Fig. 21.12 Optical transmittance spectra of the BaBPOs crystal (a) pristine crystal (b) after irradiation by X-rays for 15 min (c) after annealing at 150°C for 1 hour of the X-ray-irradiated sample.

Preparation of Standard Optical Transmittance Curve of 118-Phenyldihydrotriazole... 

Purified 118-phenyldihydrotriazole, prepared from Compound 118 and phenyl azide, was used for plotting a standard optical transmittance curve. 

Garcia, J.A. and Mandelis, A., Study of the thin-film palladium/hydrogen system by an optical transmittance method, Review Scientific Instruments, 67(11), 3981,1996. 

Band-gap energies between 1.45 eV and 1.47 eV were obtained for the films. The band-gap energies were estimated using plots of (ahv)2 versus E (Fig. 6.23), where a is an absorption coefficient estimated from optical transmittance data and hv is the photon energy. Figure 6.23 shows that the band edge... 

The turbidity level or more exactly the optical transmittance and reflectance provides a range of information about the washing and rinsing water in automatic washing and dishwashing machines. The most important parameters are soil and detergent concentration, both of which have an impact on turbidity. 

The transmittance T of a sample is a quantitative measure of how much of the light entering a sample is absorbed. (Transmittance is also called optical transmittance, which means the same thing.)... 

The measurement of an optical transmittance is only accurate if I and I0 are both determined at the same, invariant wavelength. We say the light source is monochromatic. 

Ks equilibrium constant of solubility To optical transmittance without a sample... 

To calculate the optical transmittance of a single macropore, it can be modeled by two opaque screens with an aperture of diameter d at a distance l, as shown in the inset of Fig. 10.13. For such an arrangement the ratio nt of transmitted power to incident power of a wavelength X can be approximated by... 

Fig. 4.14 (a) Optical transmittance of graphene on a polyethylene terephthalate (PET) flexible substrate [19]. Optical and electrical data for PEDOT PSS-based composites with SWCNT (b) transmittance at 550 nm, (c) sheet resistance, (d) DC conductivity and (e) ratio of DC to optical conductivity. 

The fabrication process of vanadium oxide (VO2) has also been studied using RBS/C. Since optieal and electrical properties of VO2 are dramatically changed at 68°C due to phase transition, VO2 is regarded as one of the candidates for thermally activated electronic or optical switching devices for optieal fibers or sensors. To obtain the desired properties, the development of the fabrication process for very thin films, without crystalline defects on various substrates, is required. Single-crystalline VO2 thin films on (0001) plane of a sapphire substrate have been synthesized by a laser ablation method. The quality of VO2 was examined by X-ray diffraction and RBS/C method. The eleetrieal resistanee and the optical transmittance of the VO2 film were measured under inereasing and deereasing temperatures. At a temperature of 68 °C, an abrupt transition of resistanee from metal to... 

Fig. 5.3 Optical transmittance (a) and near-normal specular reflectance (b) of CD PbS films of different thicknesses. The thickness increases from A to F over an estimated range of ca. 50 nm to <200 nm. (Adapted from Ref. 46 with permission from lOP Publishing Ltd.).

It has been found that the HNBR/SP nanocomposite provides the best thermal and mechanical properties when HNBR is dissolved in Ch and SP is dispersed in MEK. XRD, AFM,TEM, and optical transmittance studies show that the dispersion of clay is best in the Ch/MEK solvent combination and, hence, polymer-filler interaction is also highest in this system. Thus, rather than implying that the solvent selection directly affects the physical properties of the nanocomposite, solvent acts on the properties through its influence on the developed morphology. 

For instance, for a nematic polymer with positive anisotropy of dielectric constant (Ae > 0) orientation of mesogenic groups along the applied field takes place (homeo-tropic orientation). The fact of orientation is illustrated in Fig. 25, which shows that under crossed polarizers the optical transmittance I of a film of nematic polymer with optically anisotropic texture (taken for 100%) falls practically to zero when a low-frequency field is switched on. 

CPs of copolymers can be determined using the optical transmittance method (Chung et al., 1999), and even using a visual observation method (Pandya et al., 1993). Optical transmittance of aqueous polymer solutions at various temperatures can be measured using a UV/visible spectrometer. Sample and reference cells are thermostated with a circular water jacket, and the sample is monitored for the onset of turbidity. For the visual observation method, copolymer solutions at different concentrations are measured by heating them in glass tubes immersed in a well-stirred heating bath. The temperature of Lrst appearance of turbidity is taken as the CP. For both methods, the samples must be well-stirred. 

Figure 6. Optical transmittance change at 660 nm as a function of various DMMP concentrations for the optical waveguide surface coated with the PEM polymer film.

Optical transmittance, T, is a measure of how much light that enters a sample is absorbed. 

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