Ultraviolet irradiation sources

Relatively simple spectra are obtained from spin adducts of the hindered nitroso-arenes, and these may be further refined by deuteration of the spin trap (Terabe et al., 1973). In spite of being substantially dimerized, even in dilute solution,6 nitrosodurene (ND) has two considerable advantages over MNP. Firstly, it is more reactive towards radical addition (Table 5, p. 33). Secondly, it is not sensitive to visible light, and even on ultraviolet irradiation any photodecomposition is apparently not a major source of nitroxides. 

Photoirradiation and ESR Measurements. The samples of cellulose and cellulose derivatives were packed uniformly into clear fused Suprasil quartz tubes (O.D. 4 mm), which did not produce any ESR signal during the irradiated sequences. The quartz tubes containing the samples were evacuated to a constant pressure (10 6 mm Hg) and sealed. The source of ultraviolet irradiation was a high pressure mercury-xenon compact arc lamp (Conrad Hanovia type 901 BOOH, 200 W) which... 

While there appears to be some discrepancy in the conclusions derived from these studies, the difference can be explained as being caused by the exposure conditions. To illustrate the effect of irradiation wavelength on the photooxidation, unstabilized polystyrene films were exposed to the following three ultraviolet light sources having different emission characteristics (Figure 16) ... 

Hazards. Eyes and skin can be severely injured by ultraviolet radiation. One should avoid looking at the reaction mixture when the irradiation source is activated. The photochemical apparatus, especially when using immersion set-ups, must be wrapped appropriately to avoid exposure to the ultraviolet radiation. In view of the high temperatures produced by the lamp, efficient cooling is mandatory. Special care must be exercised when flammable solvents are used. Ozone is also produced, so that working in an efficient hood is essential. Furthermore, proper electrical safety is necessary to avoid high voltage shocks. 

Ions can be produced more efficiently by ultraviolet irradiation than by bombardment with electrons. The sample and carrier gas are passed in front of an ultraviolet radiation source (10.2 ev), where the sample components are ionized, but not the major components of air such as Nj, Oj, CO HjO, CO, and Ar. 

Similarly, the transient Ni(CO)3(N2) has been identified following its generation by photolysis of Ni(CO)4 in liquid krypton doped with N2 at 114 K. Ultraviolet irradiation establishes a steady-state concentration of Ni(CO)3(N2) as soon as the photolysis source is switched off, the dinitrogen complex begins to decay, reacting thermally with CO to regenerate Ni(CO)4. The kinetics of the decay reaction,... 

The intensity or radiant power of a normal Raman band depends in a complex way on the polarizability of the molecule, the intensity of the source, and the concentration of the active group, as well as other factors. In the absence of absorption, the power of Raman emission increases with the fourth power of the frequency of the source. Howeser. advantage can seldom he taken of this rclation.ship because of the likelihood that ultraviolet irradiation will cause pholodccomposi-lion of the analvle. 

Experimentally, a sample of the compound is irradiated in the gas phase by an ultraviolet light source. The emitted electrons are sorted by means of electric fields according to their kinetic energy and counted. The photoelectron spectrum is then obtained by plotting this count rate (intensity of the photoelectric current) against the energy difference /iv-JS kin (e) of equation 3. This is depicted schematically in Figure 1. 

Photo-oxidation of organic phosphorus may be performed by ultraviolet irradiation of the untreated sample by relying on the dissolved oxygen present as the source of oxidant. However, it is more usual that oxidants such as hydrogen peroxide, potassium peroxydisulphate, or ozone are added to enhance oxidation. When hydrogen peroxide is exposed to ultraviolet light, it forms hydroxyl radicals ... 

Grafting polymer by irradiation procedure has been used for the modihcation of biomaterial surfaces (Stannett, 1990). As irradiation sources, EB (Yamada et al., 1990), plasma (Pan, Wesley, Luginbuhl, Denton, Ratner, 2001), gamma ray (Biazar et al., 2010), and ultraviolet (UV) (Biazar, Khorasani, Daliri, 2011 Morra Cassinelli, 1997) are often used for preparing TRCS. These irradiation procedures can be subcategorized into (1) mutual radiation (Pan et al., 2001 Yamada et al., 1990), (2) preirradiation (Biazar et al., 2010, 2011 Della Volpe et al., 1998), and (3) peroxide (Chen, Ito, Imanishi, 1997 Rayatpisheh, Li, Chan-Park, 2012) formation approaches. Mutual radiation includes grafting polymer by EB, plasma, and UV irradiation. In the... 

Kato K., Suzuki K., Fu D., Nishizawa K., Mild T. Chemical approach using tailored liquid sources for traditional and novel ferroelectric thin films. Jpn. J. Appl. Phys. 2002a 41 6829-6835 Kato K., Suzuki K., Nishizawa K., Miki T. Ferroelectric properties of alkoxy-derived CaBi4Ti40is thin films on Pt-Passivated Si. Appl. Phys. Lett. 2001 78 1119-1121 Kato K., Suzuki K., Fu D., Nishizawa K., Miki T. Platinum-assisted phase transition in bismuth-based layer-structured ferroelectric CaBi4Ti40i5 thin films. Appl. Phys. Lett. 2002b 81 3227-3229 Nishizawa K., Mild T., Suzuki K., Kato K. Control of crystallization and crystal orientation of alkoxy-derived SrBi2Ta209thin films by ultraviolet irradiation. J. Mater. Res. 2003 18 899-907 Sanchez C., Livage J., Henry M., Babonneau F. Chemical modification of alkoxide precursors. J. Non-Cryst. Solids 1988 100 65-76... 

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