Topic
Ultraviolet light
About: Ultraviolet light is a research topic. Over the lifetime, 49494 publications have been published within this topic receiving 843151 citations.
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TL;DR: In this article, the photochemistry of elemental mercury in simulated flue gases was examined using quartz flow reactors, and the implications of photochemical oxidation of mercury with respect to direct ultraviolet irradiation of flue gas for mercury control, analysis of gases for mercury content, and atmospheric reactions are discussed.
Abstract: Photochemical reactions of mercury with various constituents in flue gas produced by burning coal could be an attractive alternative to dry sorbent- or wet scrubber-based processes for mercury control. The sensitized oxidation of elemental mercury using 253.7-nm ultraviolet radiation has been extensively studied. The photochemistry of elemental mercury in simulated flue gases was examined using quartz flow reactors. Mercury-containing simulated flue gases at temperatures between 80 and 350 °F were irradiated with 253.7-nm ultraviolet light. Results are presented for the photochemical removal of elemental mercury from simulated flue gases, as well as from nitrogen mixtures that contain oxygen, water vapor, or nitrogen oxide. Optimization of the process parameters, including light intensity, is discussed. The implications of photochemical oxidation of mercury with respect to direct ultraviolet irradiation of flue gas for mercury control, analysis of gases for mercury content, and atmospheric reactions are d...
315 citations
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TL;DR: Lifetime sun exposure appeared to be associated with a lower risk of malignant melanoma, despite the fact that lifetime sun exposure did not diminish the number of melanocytic nevi or atypical nevi, and painful sunburns nor lifetimeSun exposure were associated with an increased risk of seborrheic warts.
314 citations
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TL;DR: Stability of the nucleosome core particle to dissociation is not affected by the presence or the absence of any of the N-terminal regions of the histones, and these histone regions make very little contribution, if any, to the conformational transition that nucleosomes undergo in this range of salt concentrations.
313 citations
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TL;DR: In this article, light-emitting porous silicon (LEPOS) is described, which is made from n-type silicon by anodization in an electrolytic cell by HF with an applied electrical current.
Abstract: Experiments with light-emitting porous silicon (LEPOS) are described. The porous silicon was made from n-type silicon by anodization in an electrolytic cell by HF with an applied electrical current. Visible light emission was achieved by irradiation with ultraviolet light. Visible electroluminescence (EL) was achieved by applying a DC or AC voltage to a solid-state contact on top of the porous layer. Optical spectra from both experiments are shown. >
313 citations
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TL;DR: This investigation has demonstrated that the conversion at different depths and the maximum curing depth are dependent on the composition of the composite filling material, light source, and exposure time.
Abstract: Studies by means of infrared multiple internal reflection spectroscopy of ultraviolet and visible light polymerized composite resin materials indicated that the degree of conversion below the surface is nearly constant for most of the materials investigated until a depth is reached where the degree of conversion rapidly decreases. The maximum depth of cure has also been measured for some proprietary dental composite resin materials. This investigation has demonstrated that the conversion at different depths and the maximum curing depth are dependent on the composition of the composite filling material, light source, and exposure time. With respect to the activating system it was found that with visible light activated materials larger curing depths were obtained than with ultraviolet light activated materials. Better results with respect to curing depth were also obtained with materials containing conventional inorganic fillers than with those containing so-called microfillers.The limiting factor for tota...
313 citations