UV intensity

Sci. in press). In these studies, the PIQ (2.0 ym thick) was used as an underlayer. Thus, the film consisting of the polymer 11 and PIQ prepared on a silicon wafer was exposed to deep UV-light with the use of Canon contact aligner PLA-521 through a photomask for 5 to 6 s (UV intensity 72 mV/cm2 at 254 nm). The resulting film was then developed with a 1 5 mixture of toluene and isopropyl alcohol for 15 s and rinsed with isopropyl alcohol for 15 s. A positive resist pattern was obtained after treatment of the film pattern with 02 RIE under the condition of 0.64 W/cm2 (RF power 7 MHz, 02 pressure 3 mtorr). 

To evaluate the reactivity of model compounds III-VIII in photoinitiated cationic polymerization, we have employed real-time infrared spectroscopy (RTIR). Thin film samples of the model compounds containing 0.5 mol% of (4-n-octyloxyphenyl)phenyliodonium SbF - as a photoinitiator were irradiated in a FTIR spectrometer at a UV intensity of 20 mW/cm2. During irradiation, the decrease in the absorbance of the epoxy ether band at 860 cm-1 was monitored. 

UV intensity measurements were made with an International Light 700A Research Radiometer. The measuring head was tightly covered with aluminum foil for zeroing, and then exposed to the lamp output under exactly the same conditions as the actual samples (i.e., same distance, angle, elevation, etc.). The results of these experiments were used to evaluate the quantum yield or efficiency of the photochemical process. Specifically, photolysis of AETSAPPE... 

Contrasting with these, the CH3-terminated 99 did show a Cotton effect. This is because the chiral side chain is / -branched, so that the chiral locking effect is sufficient to afford a stable PSS conformation. CF3-terminated 98 also showed a Cotton effect, though the CD and also UV intensity were about half those of 99, presumably due to some competition between the C-F- -Si interaction and chiral side-chain packing effects. 

According to the ICH guidelines, any impurity greater than 0.1% of UV intensity by HPLC has to be characterized and identified. Traditionally, the individual impurities have to be isolated by preparative LC, and then subjected to NMR structure elucidation. The disadvantages... 

Figure 19.2 Spectral power distribution of UV radiation from a solar simulator (ORIEL) (SSUV) simulated solar zenithal UV (intense solar UVB domain) (DUV) simulated daily UV (attenuated solar UVB domain) (UVA) solar UVA (no UVB).

Advanced UV Intensity and Temperature Measurement systems UV POWERMAP and UV MAP PLUS , , Inc., Sterling, VA, Document 100200. PWRB Rev. 8/98. 

Groocock Tompkins (Ref 160) studied the decompn with 100 and 200 v-electrons at RT and found theoretical calcns agreed with exptl results. Muller Brous (Ref 52) found that photochemical decompn occurred at wave lengths below 405 mft at a rate directly proportional to the UV intensity. No relation between energies necessary for electronic and photochemical decompn was apparent. 

O3/UV detailed information about the UV-intensity, wave length spectrum, illuminance and penetration... 

The absorption maximum of ozone occurs at 254 nm, which is close to the wavelength of the mercury resonance line at 253.7 nm. The decrease of the UV intensity at X = 254 nm is proportional to the concentration of ozone based on the Lambert-Beer s law of absorption ... 

What is surprising is the catalytic activity under an ordinary fluorescent white light bulb. The UV intensity was only 11 fiW cm-2, which was ca. 1/30 that of the fluorescent black light, but the first-order degradation rate constant with the former amounts to ca. 1/3 that of the latter. The quantum efficiency at 11 juW cm-2 light intensity, calculated under the assumption that 6 holes are used to degrade... 

Fig. 7.4 Surface gloss under room light illumination (a) Ti02-free substrate with a UV intensity of 0.12 mW cm-2 (b) and (c) Ti02- coated substrate with UV intensities of 0.12 mW cm-2 and 3.5 mW cm-2, respectively. The initial value of each case was normalized to one.

Fig. 8.23 Dependence of 24 h average NO removal on UV intensity. Material, cement plates (200 cm2) [NO], 1.0 ppm, flow-rate, 1.5 1 min-1.

Fig. 7.1 Concentration of gaseous methylmercaptan in the presence of the Ti02- coated substrate (a) in the dark, (b) under fluorescent white light bulb (UV intensity 11 mW cm"2) and (c) under a fluorescent black light bulb (L) V intensity 295 mW cm"2),... 

Fig. 7.3 Sterilization of Escherichia coll on Ti02-coated substrate under room light illumination. The UV intensities were set at (a) 0.8 mW cm2 (b) 2.7 mW cm and (c) 13 mW cm-2. The ratio of numbers of colony foi Ti02-coated substrate to that for the Ti02-free substrate is represented as the surviving fraction.

A flow-type reactor similar to that shown in Fig. 8.19 was modified to make it possible to install the purifying materials. Typical conditions for laboratory testing were air flow rate, 1.5 1 min-1, NO feed concentration, 1.0 ppm relative humidity, 80% (25°C) testing peiiod, z4 h UV intensity, 0.5 mW cm-2. 

Figure 8.23 shows the effect of UV light intensity on NO removal. The removal percentage did not depend very much on the UV intensity under our experimental conditions. It is thus concluded that 0.1 mW cm-2 is enough for removing ppm levels of NO. This level of UV intensity is observed even on cloudy days in winter from the sun. Consequently, fhe air purifying materials could work in the outdoor environment during the daytime. 

Moreover, the degree of mineralization in acidic media was considerably lower than that in basic media. The differences between the degree of mineralization of CPs at different pH values can be explained partly by the more stable chlorinated intermediates at low pH. Intermediates with aromatic structures were formed soon after the beginning of the oxidation. The concentration of intermediates, however, slowly decreased during extended treatment time. By increasing the dose of oxidants or UV intensity, improved process efficiency could have been obtained, but the total mineralization of the compounds is likely to cost more in remediating waters contaminated with CPs. 

The relationship between radiation intensity and effective treatment rate might not be universally applicable to all substrates, especially when treatment parameters change. For example, when a more concentrated substrate solution was treated at various peroxide concentrations, a higher radiation level did not increase the decomposition rate however, when a less concentrated substrate solution was treated, there appeared to be some treatment system efficiency improvement at higher radiation intensity. Equation (7.1) shows that UV intensity is proportional to the concentration of hydroxyl radicals produced at constant hydrogen peroxide concentration. 

Three dominant reactions during ultraviolet (UV)/ozone (03) treatment processes that effectively decompose organic pollutants are photolysis, ozonation, and reactions of hydroxyl radicals. The generation of hydroxyl radicals is essential in this oxidation process as it is the reaction between these radicals and organic compounds that can ultimately destroy organic pollutants. Physical parameters, such as temperature, pH, initial compound and ozone concentrations, UV intensity, and ozone partial pressure will also have considerable effects on the kinetic rate constants and removal efficiency of any compound. 

Kusakabe et al. (1990) reported that total organic carbon (TOC) concentrations decrease rapidly during the first 100 min of treatment with ozone, leveling off somewhat after 100 min. Furthermore, the decomposition rate of TOC was accentuated by UV irradiation however, no direct correlation between UV intensity and TOC concentration was found. Low concentrations of TOC were still detected even after a 5-hour sampling period, indicating that the destruction of humic substances produces refractory compounds that are oxidized quite slowly (Kusakabe et al., 1990). 

Kusakabe et al. (1990) reported that the destruction rate coefficients increase as temperature increases. UV light intensity of 8.7 W/m2 yielded a slightly more than tenfold increase in the decomposition rate. The decomposition rate of ozone increases with UV intensity. These results imply that, under UV irradiation, radical chain reactions are predominant over molecular ozone reactions. When light intensity is greater than 3 W/m2, the degradation rate of TOC by UV/03 can be expressed as follows ... 

Volatile organic compounds (VOCs), especially trihalomethanes, are frequently found in drinking water due to the chlorination of humic acids. When UV irradiation is applied to the pre-ozonation of humic acids, the decomposition of VOC precursors increases (Hayashi et al., 1993). The ozonation rates of compounds such as trichloroethylene, tetrachloroethylene, 1,1,1-trichloroethane, 1,2-dichloroethane, and 1,2-dichloropropane were found to be dependent on UV intensity and ozone concentration in the aqueous phase by Kusakabe et al. (1991), who reported a linear relationship between the logarithmic value of [C]/[C0] and [03]f for 1,1,1-trichloroethane, trichloroethylene, and tetrachloroethylene. The other two organochlorines followed the same first-order kinetics with and without UV irradiation (Kusakabe et al., 1991). Thus, the decomposition rate can be expressed as ... 

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