Search results for " Thermal effects"

showing 3 items of 3 documents

Substrate and atmosphere influence on oxygen p-doped graphene

2016

Abstract The mechanisms responsible for p-type doping of substrate supported monolayer graphene (Gr) by thermal treatments in oxygen ambient have been investigated by micro-Raman spectroscopy, atomic force microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS), considering commonly employed dielectric substrates, such as SiO 2 and Al 2 O 3 thin films grown on Si. While a high p-type doping (∼10 13  cm −2 ) is observed for Gr on SiO 2 , no significant doping is found for Gr samples on the Al 2 O 3 substrate, suggesting a key role of the Gr/SiO 2 interface states in the trapping of oxygen responsible for the Gr p-type doping. Furthermore, we investigated the doping stability of Gr on SiO…

Materials sciencegenetic structuresSettore FIS/01 - Fisica SperimentaleDopingAnalytical chemistrychemistry.chemical_element02 engineering and technologyGeneral ChemistrySubstrate (electronics)Dielectric010402 general chemistry021001 nanoscience & nanotechnology01 natural sciencesNitrogenOxygenGraphene doping substrate effects thermal effects Raman Spectroscopy0104 chemical sciencesp-type doped grapheneX-ray photoelectron spectroscopychemistryoxygen annealingGeneral Materials ScienceThin film0210 nano-technologySpectroscopyCarbon
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Characterization of a fiber-reinforced new fully aromatic liquid crystalline polymer

1998

A new rigid liquid crystalline polymer that demonstrates good mechanical and thermomechanical properties and acceptable processing temperature has been recently synthesized and characterized. The melting temperature and some thermomechanical properties do not seem, however, suitable for use in some applications at high temperature or in the presence of aggressive fluids. The use of appropriate inorganic fillers can overcome these shortcomings. In this work the new LCP, polymerized in a bench-scale apparatus, and the same sample filled with carbon fibers are characterized. The properties of the carbon fiber filled LCP are compared with those of another filled wholly aromatic commercial LCP,…

chemistry.chemical_classificationFiller (packaging)Materials scienceCarbon fiber reinforced plastics Composition effects Creep Glass fiber reinforced plastics Thermal effects Semirigid liquid crystalline polymersThermomechanical properties Liquid crystal polymersLiquid crystallineMelting temperature02 engineering and technologyPolymer021001 nanoscience & nanotechnologyCondensed Matter PhysicsCharacterization (materials science)020303 mechanical engineering & transportsSettore ING-IND/22 - Scienza E Tecnologia Dei Materiali0203 mechanical engineeringchemistryPolymerizationThermalCeramics and CompositesA fibersComposite material0210 nano-technology
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Comprehensive formulation of the temperature dependent dispersion of optical materials; illustration with the case of temperature tuning of a mid-IR …

2009

International audience; The temperature dependence of refractive indices of optical materials is characterized in this work by what we call their normalized thermo-optic coefficients. These ones are determined experimentally through interferometric measurements of thermal expansion, and changes in optical thickness at a few laser wavelengths as function of temperature. A suitable vectorial formalism applied to these data allows predicting the thermal evolution of the refractive index all over the useful range of transparency. The validity and reliability of our methodology is demonstrated through temperature tuning of a mid-IR HgGa2S4 OPO, pumped at 1.0642 μm by a Nd:YAG laser. Measured the…

Physical optics : Dispersionand metrology : Refractionand metrology : Thermal effectsNonlinear optics : Parametric oscillators and amplifiersNonlinear optics : Nonlinear opticsPhysics::OpticsmeasurementDoc. ID 108930Instrumentationmaterials
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