602 research outputs found
XPS analysis of Fe2O3-TiO2-Au nanocomposites prepared by a plasma-assisted route
Fe2O3 nanodeposits have been grown on fluorine-doped tin oxide (FTO) substrates by plasma
enhanced-chemical vapor deposition (PE-CVD). Subsequently, the obtained systems have been
functionalized through the sequential introduction of TiO2 and Au nanoparticles (NPs) by means of
radio frequency (RF)-sputtering. The target nanocomposites have been specifically optimized in
view of their ultimate functional application in solar-driven H2 generation. In the present study, our
attention is focused on a detailed X-ray photoelectron spectroscopy (XPS) characterization of the
surface composition for a representative Fe2O3-TiO2-Au specimen. In particular, this report
provides a detailed discussion of the analyzed C 1s, O 1s, Fe 2p, Ti 2p, and Au 4f regions. The
obtained results point to the formation of pure Fe2O3-TiO2-Au composites, with gold present only
in its metallic state and each of the constituents maintaining its chemical identity
A study of Pt-/alpha-Fe2O3 nanocomposites by XPS
alpha-Fe2O3 matrices were deposited on Fluorine-doped Tin Oxide (FTO) substrates by Plasma Enhanced-
Chemical Vapor Deposition (PE-CVD) from Fe(hfa)_2TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA =
N,N,N’,N’-tetramethylethylenediamine). The obtained nanosystems were subsequently functionalized by platinum nanoparticles (NPs) via Radio Frequency (RF)-sputtering, exposing samples either to a pre- or post-sputtering thermal treatment at 650°C for one hour in air. Interestingly, Pt oxidation state in the final composite systems strongly depended on the adopted processing conditions. In this work, a detailed X-ray Photoelectron Spectroscopy (XPS) analysis was carried out in order to investigate the material chemical composition, with particular regard to the relative Pt(0)/Pt(II)/Pt(IV) content. The obtained results evidenced that, when annealing is performed prior to sputtering, only PtO and PtO2 are revealed in the final Pt/alpha-Fe2O3 nanocomposite. In a different way, annealing after sputtering results in the co-presence of Pt(0), Pt(II) and Pt(IV) species, the former arising from the thermal decomposition of PtO2 to metallic platinum
Evaluation of the measurement capabilities of an high performance commercial high resistance bridge by means of the comparison with two validated high resistance measurement methods
À l'Institut national de la métrologie de recherche (INRIM) ont réalisée une comparaison de mesure entre un pont de mesure de haute résistance électrique commerciale et deux méthodes de mesure de haute résistance électrique validés utilisé à l’INRIM. Ils ont procédé à une estimation de l'incertitude de mesure du pont à partir de 10 G jusqu'à 10 T. Quatre étalons de haute résistance de haut niveau à partir de
10 G jusqu'à 10 T ont été calibrés avec les trois méthodes de mesure. La compatibilité de ces mesures était bon. Quelques problèmes pour les mesures plus de 10 T et dans l'évaluation de l'incertitude de mesures du pont, cependant, restent en suspens
"Hot" Surface Activation of Molecular Complexes: Insight from Modeling Studies
Rock-and-roll over hot floors: Theoretical modeling of the first activation stages of a Cu complex on top of a heated surface (750 K) revealed two mobility regimes, a slow bump-and-rock diffusion over the surface and a fast roll-and-go motion accompanied by significant temperature-induced bond oscillations. This study enables a deeper insight into "hot" surface molecular activation processes.Tanz auf dem Vulkan: Das Modellieren der ersten Aktivierungsstufen eines Cu-Komplexes auf einer beheizten Oberfl\ue4che (750\u2005K) enth\ufcllte zwei Bewegungsarten: eine langsame Diffusion durch \u201eAnsto
fen und Taumeln\u201c und eine schnelle Rollbewegung, die mit deutlichen temperaturinduzierten Bindungsoszillationen einhergeht. Diese Befunde geben einen Einblick in die Prozesse bei der Aktivierung durch \u201ehei
fe\u201c Oberfl\ue4chen
Doenças da seringueira.
Atualmente, como no passado, varios fatores afetam de forma significativa a expansao da heveicultura e o desenvolvimento da seringueira no Brasil, desde a fase de viveiro ate a manutencao dos seringais em producao. As condicoes de umidade e temperatura da regiao sao extremamente favoraveis ao desenvolvimento de varios agentes patogenicos da seringueira. Assim, elaborou-se este documento com a finalidade de levar, aos plantadores de seringueira, conhecimentos sobre as doencas provocadas por esses patogenos em todas as suas particularidades, bem como as medidas para seu controle, fatores decisivos para o sucesso de um empreendimento heveicola, dada a importancia economica que assumem os prejuizos causados por tais molestias.bitstream/item/108584/1/CPAA-CIRC.-TEC.-4-84.pd
SobrevivĂŞncia de conĂdios de Mycosphaerella fijiensis em diferentes materiais.
Determinou-se o perĂodo de sobrevivĂŞncia de conĂdios de Mycosphaerella fijiensis sobre diversos materiais como: madeira, plástico, tecido de algodĂŁo, papelĂŁo, pneu, ferro (carcaça de automĂłvel), folhas e frutos de bananeira (Musa sp.), materiais possĂveis de transportar e disseminar o patĂłgeno a longas distâncias. Concomitantemente, avaliou-se a sobrevivĂŞncia de M. fijiensis associada a folhas de bananeira com mais de 50% da área foliar lesionada
Recultivation of abandoned monoculture areas in Amazonia.
The project concerns an experiment in recultivating a fallow rubber plantation of 19 ha by establishing mixed plantations of selected crops, mainly tree. In order to achieve sustainability, different crop combinations and different strategies for management of the spontaneous vegetation will be tested, and the crop systems will be stabilized by inoculation the plants with spores of mycorrhizal fungi. The experimental area was divided into five blocks with eighteen plots each to test four mixed cultivation systems, compared to four conventional monoculture systems. Fallow plots will be analyzed for reference. The scientific research is focused on the ecological role of mycorrhizal fungi in the field trial, analysis of the structural and functional traits of the structural and functional traits of the spontaneous vegetation due to management, and identification and control of plant diseases. In addition, economic and acceptance studies will be conducted to find out whether farmers are willing to apply the tested cultivation systems. In the 19 ha plantation, intend to test the three following ways of stabilizing crops using different variants and to analyze the crop systems on a scale that is close to practical conditions: 1. inoculation of the plants with spores of mycorrhizal fungi; 2. testing of different mixed cultivation systems; and experiment on management of the spontaneous vegetaion in the crop systems to improve the competitive conditions for the planted crops
On the calibration of DC resistance ratio bridges
Current comparator bridges are employed for the realization of the resistance scale from the quantum Hall effect in several National Metrology Institutes and calibration centers. Quantum resistance standards under development, based on novel materials and tabletop dry cryostats, make the more achievable DC current comparator bridges (DCCs) a viable alternative to the more accurate but more expensive cryogenic current comparator bridges (CCCs). A DCC ratios' calibration against a reference CCC is a straightforward way to improve the DCC's performances and the resistance scale overall accuracy.The paper reports the calibration results of two DCCs on the ratios employed in a 1 omega to 10 k omega resistance scale traceable to a 12.906 k omega quantized Hall resistance, showing a good reproducibility and stability of the DCC readings over the measurement period and supporting the possibility of a DCC errors' correction and of a realization of the primary resistance scale at the 10-8 level
Exogenous Influences on the Growth Dynamics of High Quality Timber Species from the Amazon .
In this study special attend was given to the important species for high quality wood production Swietenia macrophylla, Carapa guianensis, and Cedrela odorata (Meliaceae)
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