Near-UV radiation

A 0.3 fin thick SPP layer was exposed to a 20 kV electron beam followed by a flood exposure using near UV radiation with an integrated dose of over 500 mJ/cm2. Such a dose was sufficient to convert the remaining DNQ to indenecarboxylic acid. The resist was then dip-developed In an aqueous TMAH solution for 60 s at 25°C. 

A 0.4 m thick SPP layer was exposed to X-rays followed by a flood exposure using near UV radiation. The resist was then dip-developed in a 0.8 wt% TMAH solution for 60 s at 25 °C. We used two x-ray exposure systems to evaluate the characteristics of the SPP resist. One is SR-114 which has a source composed of a molybdenum rotating anode with a 0.54 nm Mo-La characteristic line. The exposure was carried out in air. The other has a synchrotron radiation source with a central wavelength of 0.7 nm (KEK Photon Factory Beam Line, BL-1B). The exposure was carried out in vacuum (<10-4 Pa). A positive resist, FBM-G,15) was used as a standard, because its sensitivity only weakly depends on the ambient. 

Figure 3. Sensitivity curves of SPP image reversal (solid line) after 20kV EB exposure compared with a novolac-based resist (dashed line). A 0.3 //m thick resist layer was exposed to EB followed by a flood exposure using near UV radiation and then dip-developed in an aqueous THAH solution for 60 s at 25°C. TMAH concentration A 0.65 wt%, B 0.70 wt%, C 0.80 wt%, D 1.2 wt%.

Hartman, PS. Eisenstark, A. (1978) Synergistic killing of Escherichia coli by near-UV radiation and hydrogen peroxide distinction between recA-repairable and recA-nonrepairable damage. J. Bacterial., 133, 769-774... 

Virtually all forms of life are exposed to energy-rich radiation capable of causing chemical changes in DNA Near-UV radiation (with wavelengths of 200 to 400 nm), which makes up a significant portion of the solar spectrum, is known to cause pyrimidine dimer formation and other chemical changes in the DNA of bacteria and of... 

In practice, 8-methoxypsoralene is used as the photoactive agent. It can be taken orally by the patient who will then be exposed to near UV radiation some 2 hours later. The treatment has however side-effects which make it relatively dangerous. 

Yentsch, C. S. and Yentsch, C. M., The attenuation of light by marine phytoplankton with specific reference to the absorption of near-UV radiation, in The Role of Solar Ultraviolet Radiation in Marine Ecosystems, Calkins, J., Ed., Plenum Press, New York, 1982, 691. 

Figure 12 shows results of a thermal-aging experiment. Sheets of Whatman No. 42 filter paper were first exposed to near-UV radiation (BLB fluorescent black lights), after which they were subjected to oven... 

Tests using hemicellulosic extracts from several different pulp stocks indicate that little if any discoloration is caused by exposure of these components to visible and near-UV radiation or even radiation at 254 nm (UV). In the continuing quest to understand the causes of discoloration in paper, these results support the contention that the tendency of hemicelluloses to lead to discoloration is primarily a thermally induced effect. 

Values are for nonresonant scattering of visible and near-uv radiation by atmospheric gases resonant Raman scattering approaches 10 ... 

The improvement of photostability of jute fabric itself is an important matter to be given priority. Various processes have been developed in which bleached jute does not revert to its natural colour on exposure to light. The blocking of reactive phenolic groups by etherification or esterification is expected to arrest the yellowing process. The presence of some chromophore in dyes can cause absorption of near uv-radiation of sunlight and prevent discolouration. Bleached jute goods treated with copper-potassium dichromate (0.25% o.w.f) improve photostability over conventional bleached fabric [123]. 

This cell used a wide-gap semiconductor BaTiOs Eg = 3.3 eV). This is capable of absorbing only near UV radiation, which comprises less than 5% of available solar energy, and this limits the practical use of the cell for solar energy conversion. 

Polyhaloalkane-arylamine systems. Free-radical imaging systems utilizing intermediates generated from polyhaloalkane compounds by near-UV radiation and able to react with arylamlnes can form print-out colored images (141). 

Table 9.1 6 Mechanical properties of glass fabric/TS polyester RPs exposed to various intensities of near UV radiation in a vacuum... 

The principle is that the near-UV radiation generates electron-hole pairs in the halide particles. The electrons are trapped by the interstitial Ag ions producing Ag colloids on the surface of the halide particle. The activation energy for this process is only 0.06 eV so the Ag ion moves easily in the halide in addition, a small amount of Cu increases the effect by at least an order of magnitude. This is the same process used in photography and is explained by the same Gurney-Mott theory. The metal particles formed in the process are 1-5 nm in size, but because the halide must be >5 nm to show the effect the second annealing T is critical. 

Absorption measurements in the vacuum UV resulted in the detection of two Rydberg transitions originating from the metastable a state and of one n<-X transition which possibly is also of Rydberg type. Another Rydberg transition, s+ b was detected as a two-photon process with near-UV radiation however, this transition was suggested to be one to a state of mainly valence character, d S+ b... 

The introduction of species from fossil fuel combustion (Section 11. A. 1) into the lower atmosphere leads to an extensive series of chemical reactions, most of which are of free-radical type. They can be divided into three categories daylight (D) reactions, requiring solar near-UV radiation night (N) reactions, which are important in the absence of sunlight and 24-hr (DN) reactiorrs. 

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