Search results for "chemical compositions"

showing 2 items of 2 documents

Characterisation of the magmatic signature in gas emissions from Turrialba Volcano, Costa Rica

2014

The equilibrium composition of volcanic gases with their magma is often overprinted by interaction with a shallow hydrothermal system. Identifying the magmatic signature of volcanic gases is critical to relate their composition to properties of the magma (temperature, fO2, gas-melt segregation depth). We report measurements of the chemical composition and flux of the major gas species emitted from Turrialba Volcano during March 2013. Measurements were made of two vents in the summit region, one of which opened in 2010 and the other in 2012. We determined an average SO2 flux of 5.2 ± 1.9 kg s-1 using scanning ultraviolet spectroscopy, and molar proportions of H2O, CO2, SO2, HCl, CO and H2 ga…

010504 meteorology & atmospheric sciencesStratigraphyChemical compositionContinuous emissionSoil ScienceMineralogyVolcanoe010502 geochemistry & geophysics01 natural sciencesHydrothermal circulationVolcanic GasesHydrothermal systemFlux (metallurgy)lcsh:StratigraphyMagmatic signaturesGeochemistry and PetrologyUltraviolet spectroscopyeventGas compositionFourier transform infrared spectroscopyChemical compositionlcsh:QE640-6990105 earth and related environmental sciencesEarth-Surface Processesevent.disaster_typegeographygeography.geographical_feature_categorylcsh:QE1-996.5Fourier transform infrared spectrometryPaleontologyFourier transform infrared spectroscopyGeologyChemical signatureGas-sensing systemlcsh:GeologyGeophysicsVolcanoCarbon dioxideSulfur dioxide13. Climate actionEquilibrium compositionMagmaCarbon dioxide; Fourier transform infrared spectroscopy; Sulfur dioxide; Ultraviolet spectroscopy; Volcanoes; Chemical compositions; Chemical signatures; Continuous emission; Equilibrium compositions; Fourier transform infrared spectrometry; Gas-sensing systems; Hydrothermal system; Magmatic signaturesGeology
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Chemical composition of two-photon oxidized graphene

2017

Chemical composition of two-photon oxidized single-layer graphene is studied by micrometer X-ray photoelectron spectroscopy (XPS). Oxidized areas with a size of 2 × 2 μm2 are patterned on graphene by tightly focused femtosecond pulsed irradiation under air atmosphere. The degree of oxidation is controlled by varying the irradiation time. The samples are characterized by four wave mixing (FWM) imaging and Raman spectroscopy/imaging. Micrometer-XPS is used to study local chemical composition of oxidized areas. XPS imaging shows good contrast between oxidized and non-oxidized areas. Gradual oxidation is observed from growth of signals attributed mainly to hydroxyl (Csingle bondOH) and epoxide …

Materials sciencechemical compositionsOxidechemistry.chemical_element02 engineering and technology010402 general chemistryPhotochemistry01 natural scienceslaw.inventionMicrometresymbols.namesakechemistry.chemical_compoundX-ray photoelectron spectroscopylawOrganic chemistryGeneral Materials ScienceIrradiationChemical compositionta116ta114GrapheneGeneral Chemistry021001 nanoscience & nanotechnology0104 chemical scienceschemistrysymbols0210 nano-technologyRaman spectroscopyCarbonCarbon
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