Search results for "SB"

A estação do neolítico antigo do Carrascal (Oeiras, Lisboa, Portugal)

2011

Apresentam‑se os resultados preliminares da intervenção arqueológica realizada no Carrascal entre 2003 e 2005 em local implantado em encosta de declive suave do vale da ribeira de Barcarena (concelho de Oeiras, distrito de Lisboa) e a cerca de 3 km de distância da margem norte do estuário do Tejo, nas proximidades de enseada, formada no sopé da encosta, a qual proporcionava importante actividade recolectora, destacando‑se a ostra (Ostrea edulis). A indústria de pedra lascada evidencia fabrico local, tal é a abundância de restos de talhe encontrados; o mesmo se verifica com a produção de artefactos de pedra polida, confeccionados essencialmente em rochas de origem local; na indústria cerâmic…

Höchstgerichtsbarkeit in den südlichen Niederlanden (16./17. Jahrhundert) : Nicolas du Fief und die Praxis des Grossen und des Geheimen Rates

2008

Taxas de substituições das Annonaceas: uma perspectiva do modelo códon

2014

The Annonaceae includes cultivated species of economic interest and represents an important source of information for better understanding the evolution of tropical rainforests. In phylogenetic analyses of DNA sequence data that are used to address evolutionary questions, it is imperative to use appropriate statistical models. Annonaceae are cases in point: Two sister clades, the subfamilies Annonoideae and Malmeoideae, contain the majority of Annonaceae species diversity. The Annonoideae generally show a greater degree of sequence divergence compared to the Malmeoideae, resulting in stark differences in branch lengths in phylogenetic trees. Uncertainty in how to interpret and analyse these…

Life Cycle Study of a Diabatic Rossby Wave as a Precursor to Rapid Cyclogenesis in the North Atlantic—Dynamics and Forecast Performance

2011

Monthly Weather Review, 139 (6)

Clinical Experience with Ceftazidime-Avibactam for the Treatment of Infections due to Multidrug-Resistant Gram-Negative Bacteria Other than Carbapene…

2020

Background: Experience in real clinical practice with ceftazidime-avibactam for the treatment of serious infections due to gram&minus

conversion electron Mössbauer study of low carbon steel polarized in aqueous sulfate solution containing sulfite in low concentration

1992

The passivation of low carbon steel was studied in aqueous solution of 0.5 M Na2SO4+0.001 M NaHSO3 at pH=3.5 and 6.5. The found major components at pH-3.5 were: γ-FeOOH and Fe3C, and also FeSO4.H2O could be identified on the surface of the low carbon steel as a minor component. At pH-6.5, the passive film contained only amorphous iron(III)-oxide or oxyhydroxide.

Electrochemical and conversion electron mössbauer study of corrosion induced by acid rain

1993

Abstract The passivation of low carbon steel was studied in aqueous solution of 0.5M Na2SO4 +0.001M NaHSO3 (pH 3.5, 6.5 and 8.5) which can be considered as a model of acid rain. The used conversion electron Mossbauer spectroscopy (CEMS) with the complementary electrochemical investigations proved that the sulfite ions induce pitting corrosion at pH 3.5 and 6 5 while the measurements showed much weaker pitting at pH 8.5. The compositions and thicknesses of the passive films formed during the electrochemical treatments are determined from the CEM spectra. Only γ-FeOOH was found on the surface of the samples at pH 6.5 and 8.5. Nevertheless, at pH 3.5 the sextet belonging to Fe3C appears in the…

Time integral and time differential Mössbauer measurements on [57Co/Mn(bipy)3](PF6)2

1994

The Mossbauer emission spectra of nucleogenic iron(II) complexes with a low spin (LS) ground state show two metastable iron(II) high spin (HS) states at low temperatures. In order to identify these metastable HS states, the compound [57Co/Mn(bipyridine)3](PF6)2 has been studied by time differential Mossbauer emission spectroscopy (TDMES) and optical lifetime measurements of excited electronic states in the corresponding Fe-doped Mn compound. The lifetime of one of the HS states of the nucleogenic iron(II) determined by TDMES has been measured to be the same as the lifetime of the laser-excited iron(II) electronic state.

Layer formation on silicon steel by processing in H2/H2O at elevated temperatures

1992

Silicon steel (Fe-3wt%Si), as used for transformers and generators, has been annealed in wet hydrogen at elevated temperatures. The composition, sequence, and thicknesses of the layers found by conversion electron Mossbauer spectroscopy (CEMS) and Auger electron spectroscopy (AES) depth profiling for a 10 minutes anneal in different atmospheres are reported. In the range from 500°C to 720°C we observed carbide formation, indicating that the decarburization is hindered. Above 800°C, the layers consist of fayalite or of fayalite and iron oxides, depending on the oxygen potentialaO. At 843°C, the onset of iron oxide formation was found ataO=0.33.

Anodic layers formed on steel in phosphate buffer solution

1986

In-situ gamma scattering and ex-situ conversion electron Mossbauer, and Auger spectroscopy were applied to investigate anodic layers on steel. Samples treated in the active potential range in phosphate buffer solution show a Fe(II)-phosphate deposit on the surface. After treatment in the passive potential region, only Fe3+was found to exist in the oxide layer. The passive layer does not consist of stoichiometric oxidic phases.