Search results for "SiO2 nanoparticle"

showing 3 items of 13 documents

Luminescence Efficiency of Si/SiO 2 Nanoparticles Produced by Laser Ablation

2019

Photoluminescence properties of Si(core)/SiO 2 (shell) nanoparticles produced by pulsed laser ablation in aqueous solution are investigated with the purpose to highlight the microscopic processes that govern the emission brightness and stability. Time resolved spectra evidence that these systems emit a µs decaying band centered around 1.95 eV, that is associated with the radiative recombination of quantum-confined excitons generated in the Si nanocrystalline core. Both the quantum efficiency and the stability of this emission are strongly dependent on the pH level of the solution, that is changed after the laser ablation is performed. They enhance in acid environment because of the H + pass…

PhotoluminescenceLaser ablationMaterials scienceSi/SiO2 nanoparticles pulsed laser ablation quantum confinement luminescence IR absorption pH dependencebusiness.industry2Surfaces and InterfacesCondensed Matter Physicslaser ablation; pH dependence; photoluminescence; quantum confinement; Si/SiO ; 2; nanoparticlesquantum confinementSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsQuantum dotSio2 nanoparticleslaser ablationMaterials ChemistryPh dependenceOptoelectronicsphotoluminescencenanoparticlespH dependenceElectrical and Electronic EngineeringLuminescencebusinessSi/SiOphysica status solidi (a)
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The role of nanoparticles in decreased washout of underwater concrete

2019

Abstract The paper presents research results of the influence of SiO2 nanoparticles on the washout of underwater concrete and hardened concrete. Based on infrared spectroscopy (FTIR) and thermogravimetric (TGA) analyses of the applied anti-washout admixture (AWA), its chemical structure was determined. A beneficial effect of SiO2 nanoparticles on the reduction of the mix washout was demonstrated and the most probable reason for that phenomenon was given, taking into account the AWA chemical structure and its behaviour in the concrete mix environment. It was found that a dosing method of AWA and nanoparticles to the concrete influenced the washout.

Thermogravimetric analysisMaterials sciencefresh concreteChemical structure0211 other engineering and technologiesInfrared spectroscopyWashoutNanoparticle020101 civil engineering02 engineering and technologyBuilding and Construction0201 civil engineeringChemical engineeringfinenessSio2 nanoparticles021105 building & constructionadmixturenanoparticlesGeneral Materials ScienceFourier transform infrared spectroscopyCivil and Structural EngineeringConstruction and Building Materials
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Assessment of protection treatments for carbonatic stone using nanocomposite coatings

2020

In this paper the effect of the application of four kinds of polymer dispersions containing nanoparticles, used as protectives, on two type of carbonatic lithotypes, White Noto and Comiso stone, is reported. The study was conducted by analysing the contribution of each component of the system. After the structural characterization of the coating itself, the performance of those colloidal systems has been studied upon application on the calcarenites, preferring non-invasive techniques and microdestructive techniques. Effect of the nanoparticles presence on hydrorepellency and roughness of the stone surface and on chromatic changes has also been considered. The tests conducted have proven tha…

WaterproofingMaterials scienceStone protection treatmentGeneral Chemical EngineeringWaterproofingNanoparticle02 engineering and technologyengineering.material010402 general chemistry01 natural sciencesCoatingMaterials ChemistrySilicon dioxideComposite materialNanocompositeNanodispersionOrganic ChemistryStone protection treatmentNanodispersionsTitanium dioxideWaterproofingSilicon dioxide021001 nanoscience & nanotechnology0104 chemical sciencesSurfaces Coatings and FilmsSio2 nanoparticlesengineeringTitanium dioxide0210 nano-technology
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