Search results for "Controlled atmosphere"

showing 9 items of 9 documents

Experimental Equipment for Studying the Residual Stresses Developed During High Temperature Reactions by X-Ray Diffraction

1996

This paper describes a device dedicated to studyng, by X-ray diffraction the residual stresses developed on surface samples as a function of temperature and atmosphere conditions. The setup consists of : a.) an horizontal axis goniometer which allows the programmed positionning of the sealed X-ray source and of the linear detector. b.) a high temperature controlled atmosphere chamber Particular attention has been paid to the thermal stability up to 1200°C and the accurate position on the sample.

010302 applied physicsDiffractionControlled atmosphereChemistrybusiness.industryDetectorGeneral Physics and Astronomy02 engineering and technology021001 nanoscience & nanotechnology01 natural sciencesAtmosphereOpticsResidual stressGoniometer[PHYS.HIST]Physics [physics]/Physics archives0103 physical sciencesX-ray crystallographyThermal stability0210 nano-technologybusiness
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In-situ monitoring by Raman spectroscopy of the thermal doping of graphene and MoS2 in O-2-controlled atmosphere

2017

The effects of temperature and atmosphere (air and O2) on the doping of monolayers of graphene (Gr) on SiO2 and Si substrates, and on the doping of MoS2 multilayer flakes transferred on the same substrates have been investigated. The investigations were carried out by in situ micro-Raman spectroscopy during thermal treatments up to 430 °C, and by atomic force microscopy (AFM). The spectral positions of the G and 2D Raman bands of Gr undergo only minor changes during treatment, while their amplitude and full width at half maximum (FWHM) vary as a function of the temperature and the used atmosphere. The thermal treatments in oxygen atmosphere show, in addition to a thermal effect, an effect a…

Controlled atmosphereMaterials science2Analytical chemistrythermal dopingGeneral Physics and Astronomychemistry.chemical_elementtwo-dimensional (2D) materials02 engineering and technologyMoSlcsh:Chemical technology010402 general chemistrylcsh:Technology01 natural sciencesOxygenFull Research Paperlaw.inventionPhysics and Astronomy (all)symbols.namesakelawMonolayerNanotechnologylcsh:TP1-1185General Materials ScienceElectrical and Electronic Engineeringlcsh:ScienceSpectroscopylcsh:TGrapheneSettore FIS/01 - Fisica SperimentaleDopinggraphenetechnology industry and agriculture021001 nanoscience & nanotechnologylcsh:QC1-9990104 chemical sciencesNanoscienceFull width at half maximumTwo-dimensional (2D) materialchemistryRaman spectroscopysymbolslcsh:QMaterials Science (all)0210 nano-technologyRaman spectroscopyMoS2lcsh:Physics
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Controlled temperature grinding under modified atmosphere for Almond (Prunus Dulcis) paste production

2011

The quality of the raw material and the processing conditions have a great influence on the nutritional properties of finished products. This research is focused on almond paste production and aims at developing a new production process to deliver the high nutritional content of the raw almonds into the finished product. Raw almonds are composed mainly of fats (approx. 50%) and proteins (approx. 25%), and are particularly rich in omega 6 fatty acids, and are hence exposed to denaturation and oxidation phenomena during the traditional grinding/homogenization process. The study involved the analysis of six different local cultivars based upon the main nutritional indicators (protein content, …

Protein contentPrunus dulcisControlled atmosphereChemistryModified atmospherefood and beveragesProduction (economics)Food scienceCultivarRaw materialGrindingInternational Journal of Engineering, Science and Technology
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Rapid and eco-friendly synthesis of graphene oxide-silica nanohybrids

2014

The increasing interest in Graphene oxide (GO) is due to many issues: the presence of both sp2-conjugated atoms and oxygen-containing functional groups provides a strong hydrophilicity and the possibility to further functionalize it with other molecules (i.e. π-π interactions covalent attachment etc.) [1]. Furthermore since the GO is biocompatible and noncytotoxic many studies have been recently focused on the development of GO-based nanodevices for bioimaging DNA detection drug delivery. Due to their low cytotoxicity and large internal surface area silica nanoparticles have been taken into account as promising material for biolabeling and drug loading/delivery. Particular consideration has recently been demonstrated for GO-silica composites because of the potentialities for electrical applications their chemical inertia and stability toward ions exposure. The possibility to combine the extraordinary properties of GO and silica offers several advantages for the realization of nanoprobes for biological applications and of biosensor [12]. The strategy for the fabrication of GO-nanosilica nanohybrids can be schematized as follows: (i) synthesis of GO by oxidizing graphite powder with the method described by Marcano et al. [3] (ii) Preparation of oxygen-loaded silica nanoparticles by thermal treatments in controlled atmosphere in order to induce high NIR emission at 1272 nm from high purity silica nanoparticles. (iii) preparation of GrO-silica nanohybrid films via rapid solvent casting in water. The nanohybrids were tested by XPS FTIR Raman analysis UV photoluminescence analysis TGA Zeta potential measurements electrical tests AFM and SEM. Several nanohybrids were prepared by combining two different typologies of GO and two different samples of silica.
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Improvement of plum storage with modified atmosphere packaging

2010

Post-harvest supply chain is a critical point for agro-food marketing. The management of freshness in the storage is fundamental to maintain high profits in the agro-food sector to improve the distribution and to respond to retailers and consumers' requirements. Plums are considered to have a climacteric-ripening pattern, in which ethylene is the hormone responsible for ripening. Modified atmosphere (MA) storage is a method helpful to maintain the natural quality of fruits. MA added to low temperatures influence fruit metabolism and reduce ethylene production, weight losses, hardness of pulp, preserving vitamins and organic acids. The objective of this study was to increase the condition of…

Controlled atmospherepost-raccoltaChemistryPlumPlastic filmStoragefood and beveragesCold storageRipeningTitratable acidHorticultureShelf lifeQualitySettore AGR/03 - Arboricoltura Generale E Coltivazioni ArboreeModified atmosphereHorticultureModified atmosphere Packaging Plum Quality StoragePackagingModified atmospherePostharvestsusino
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Defect-related visible luminescence of silica nanoparticles

2013

The high photon emissivity in the visible spectral range is one of the most relevant phenomena emerging from the reduction of silica down to nanoscale; hence it is promising for the development of optical nanotechnologies (down converter, probes, display). It is well accepted that the origin of this luminescence is related to the high specific surface (~100 m2/g) that favors the formation of optically active defects at the nanosilica surface. With the aim to clarify the role of specific luminescent defects, here we report a detailed study of spectral and decay features by time-resolved photoluminescence spectra under a visible-UV tunable laser excitation. Our study is carried out on differe…

Silica nanoparticlesControlled atmosphereMaterials scienceAnalytical chemistryUv lasersilica nanoparticles time resolved luminesce surface defectssilica nanoparticles time-resolved luminescence surface defects laser irradiation effectsLuminescence spectraIrradiationCondensed Matter PhysicsPhotochemistryLuminescenceBlue band
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Graphene p-Type Doping and Stability by Thermal Treatments in Molecular Oxygen Controlled Atmosphere

2015

Doping and stability of monolayer low defect content graphene transferred on a silicon dioxide substrate on silicon are investigated by micro-Raman spectroscopy and atomic force microscopy (AFM) during thermal treatments in oxygen and vacuum controlled atmosphere. The exposure to molecular oxygen induces graphene changes as evidenced by a blue-shift of the G and 2D Raman bands, together with the decrease of I2D/IG intensity ratio, which are consistent with a high p-type doping (∼1013 cm-2) of graphene. The successive thermal treatment in vacuum does not affect the induced doping showing this latter stability. By investigating the temperature range 140-350 °C and the process time evolution, …

Controlled atmosphereMaterials scienceSiliconGrapheneElectronic Optical and Magnetic MaterialDopinggrapheneSettore FIS/01 - Fisica SperimentaleAnalytical chemistrychemistry.chemical_elementSurfaces Coatings and FilmSubstrate (electronics)Thermal treatmentOxygenSurfaces Coatings and FilmsElectronic Optical and Magnetic Materialslaw.inventionGeneral EnergyEnergy (all)chemistrylawMonolayeroxygen annealingp-type dopingPhysical and Theoretical Chemistry
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Environment assisted photoconversion of luminescent surface defects in SiO 2 nanoparticles

2017

Abstract Time-resolved photoluminescence investigation on SiO 2 nanoparticles was carried out in controlled atmosphere, with the aim to discern the effects induced on the typical blue luminescence band by high power UV Nd:YAG laser photons (4.66 eV) and by some selected molecular species of the air (O 2 , N 2 , CO 2 , H 2 O). These factors ultimately determine both the brightness and photostability of the emitting defect, so as to limit the unique and attracting potentialities offered by this system in many applicative fields. Here it is highlighted that the effects due to photons and molecules, singularly considered, are not additive, the radiation being more dramatic in reducing the emiss…

Controlled atmospherePhotoluminescenceMaterials scienceGeneral Physics and AstronomyNanoparticleSiO2 nanoparticle02 engineering and technology010402 general chemistryPhotochemistry01 natural sciencesFluenceSurface defectlaw.inventionlawQuenchingSpectroscopyQuenchingbusiness.industryTime-resolved luminescenceSurfaces and InterfacesGeneral Chemistry021001 nanoscience & nanotechnologyCondensed Matter PhysicsLaser0104 chemical sciencesSurfaces Coatings and FilmsPhotostabilityBleachingOptoelectronics0210 nano-technologyLuminescencebusinessApplied Surface Science
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Monolayer graphene doping and strain dynamics induced by thermal treatments in controlled atmosphere

2018

Time dynamics of doping and strain induced in single layer graphene by thermal treatments up to 300 degrees C in vacuum, nitrogen, carbon dioxide and oxygen controlled atmosphere are deeply studied by Raman spectroscopy and they are compared with its morphological evolution investigated by Atomic Force Microscopy. The reaction dynamics in oxygen treatments is determined down to a time scale of few minutes as well as that of dedoping process made by water vapor treatment. The interplay of strain modification and doping effects is separated. The strain is clarified to be strongly influenced by the cooling time. The doping removal is dominated by the water vapor, showing that the concentration…

inorganic chemicalsControlled atmosphereAnalytical chemistrychemistry.chemical_element02 engineering and technologydoping010402 general chemistry01 natural sciencesOxygenStrainAtmosphereCondensed Matter::Materials Sciencesymbols.namesakeThermalGeneral Materials ScienceRamanDopinggraphenetechnology industry and agricultureGeneral Chemistry021001 nanoscience & nanotechnologyNitrogen0104 chemical scienceschemistryChemical engineeringGraphene Thermal Doping Chemistry (all)symbolsAFM0210 nano-technologyRaman spectroscopyWater vapor
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