Extinction co-efficient

It I0 is the intensity of light which passes through the solution and If the intensity of the same light which passes through the solvent, then IQ/It is called transmittance. From the thickness of the cell and I0/It, absorption co-efficient or extinction co-efficient is calculated. Then log I0/It is plotted against X. The maximum absorbance will be given by the maxima in the curve. 

Compound Absorption peak ( mJ nm Molar extinction co-efficient T max... 

The amounts of total protein in crude extracts are estimated using a colometric assay such as the Coomassie Plus Protein assay reagent (Pierce) or equivalent. The amount of purified recombinant chemokine protein is determined by UV spectroscopy at 280 nm. The extinction co-efficient is calculated from the amino acid composition according to the formula ... 

An earlier procedure described by Katz and Comb (1963) separates Up, Gp and (Ap + Cp) in the first stage and then Ap and Cp in the second stage. Because of the different absorption spectra of Ap and Cp only the first stage may be necessary for nucleotide composition determination. Moderate volumes of eluant are used so sensitivity is reasonable (50 to 100 nmoles of each nucleotide, or about 0.1 mg RNA) (Katz and Comb 1963 Nishimura et al. 1967). The first column is 0.9 x 5.0 cm of Dowex 50 H " ( x 4, 200-400) washed with 3 N HCl, water until neutral, and finally with 20 ml 0.05 N HCl. The sample of nucleotides, in 0.05 N HCl, is loaded onto the column and washed in with 1 ml 0.05 N HCl. Up is eluted with 5 ml 0.05 N HCl. The column is then eluted with water at 1 ml/min or less. Gp is eluted in the first 7.5 ml of water effluent and Ap and Cp in the next 25 ml. The nucleotide composition of the sample may be determined from the extinction co-efficients of the fractions (at 2 wavelengths for the Ap and Cp fraction). 

Chemicals used were of standard analytical grade. Fe(lll) was analysed by complexomentric (EDTA) titration [5] with NH4SCN indicator at pH 3. Fe(Il) was estimated by deducting Fe(III) from total Fe found after oxidation of a mix of Fe(IlI) and Fe(II) solution. Chromium was estimated spectrophotometrically at mO 373 as chromate with molar extinction co-efficient of 4815 in IM NaOH solution. Sulphate was analysed by a Nephelometer against a calibrated curve of standard BaS04 suspension. 

Optical transmission spectra of the films irradiated with H+ ions are shown in Figure 9.13a. A maximum transmittance of about 75% is observed for the as-deposited film whereas the transmittance is decreased for the ion-implanted samples. From the transmittance data, the refractive index and extinction co-efficient are evaluated. The index of refraction value of n=2 and the extinction co-efficient value of nearly k=0 in the visible region is obtained and these values are typical of most of the spinel transparent conducting oxide (TCO) materials. 

One factor which should be noted for palladium, which also applies to the observation of the transition metals Is that not all crystallites have the same efficiency for diffracting electrons, l.e., as the atomic number decreases, the extinction distance for the crystallite Increases (13). Thus one would anticipate Chat as the mean atomic number decreases, the crystallites will have Co be progressively larger to enable visual observation on a support such as alumina. 

Figure 53.8 shows that the generation efficiencies of CO, mixture of hydrocarbons, and smoke increase significantly with increase in the Halon concentration. The effect of Halon on the generation efficiencies is strong for CO and the mixture of hydrocarbons and weak for smoke. This type of combustion behavior of PMMA is similar to one found with the ventilation controlled combustion, i.e., increasing preference of fuel carbon atom to convert to CO and the mixture of hydrocarbons rather than to smoke. It thus appears that the chemical interruption processes for flame extinction by Halon and reduced oxygen are very similar. 

FIGURE 53.8. Generation efficiencies of CO, mixture of hydrocarbons, and smoke versus time for the combustion of 100 mm X 100 mm x 25 mm thick horizontal slab of polymethylmethacrylate exposed to 40 kw/m in co-air flow with varying Halon 1301 concentration at a velocity of 90 mm/s in the ASTM E 2058 FPA. Numbers and their locations represent Halon 1301 concentrations in volume percents and application times. Times for flame instability, liftoff, and extinction are also indicated. 

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