Search results for "Solid"
showing 10 items of 3575 documents
Application of pressurized fluid extraction to determine cadmium and zinc in plants
2006
Abstract A procedure for the determination of Cd and Zn in plants is proposed. The metals are extracted by pressurized fluid extraction (PFE). Operational conditions are: pressure 1500 psi, temperature 75 °C, static time 5 min, flush volume 35%, purge time 60 s, cycles 1 and 1,2-diaminocyclohexane- N , N , N ′, N ′-tetraacetic acid (CDTA) 0.01 M at pH 4.5 as extracting solution. Determination of Zn is carried out by flame atomic absorption spectroscopy and depending on the concentration level, Cd content is determined by flame or electrothermal atomic absorption spectroscopy. Certified samples of Virginia tobacco leaves, tea leaves, spinach leaves, poplar leaves, a commercial spinach sample…
Influence de l'atmosphère gazeuse sur la cinétique de formation du titanate de baryum par réaction solide-solide
1986
International audience; Les études consacrées à la synthèse, par réaction solide-solide, du titanate de baryum (BaTiO3) ont montré l'importance des propriétés physicochimiques des solides initiaux (BaCO3 et TiO2) sur les propriétés du titanate obtenu. Lors de l'élaboration de céramiques diélectriques, il est en effet nécessaire d'éviter la formation de phases intermédiaires (Ba2TiO4, BaTi4O9, ...) qui nuisent à leurs propriétés diélectriques. La présence de ces phases peut être liée à une maîtrise imparfaite des nombreux paramètres influant sur la cinétique de la réaction. Le rôle de deux de ces paramètres : les traitements mécaniques et la nature de l'atmosphère gazeuse, fait l'objet de ce…
Recognition and Civic Selection
2021
Large-scale immigration and the refugee crisis have caused many states to adapt ever stricter civic selection processes. This paper discusses the challenges arising from civic selection from the perspective of recognition theories. The argument is that recognition theories provide good conceptual tools with which to critically analyze civic selection and immigration. However, the paper also aims to highlight that many current institutional practices are problematic from the perspective of recognition. In the context of civic selection, it is helpful to understand recognition as something that comes in two analytically distinct modes: horizontal (or interpersonal) and vertical (or institutio…
Il progetto CEAS: quando l’educazione alla cittadinanza è già attiva e solidale. Buone pratiche di educazione alla solidarietà
2005
Solid-state-biased coherent detection of ultra-broadband terahertz pulses
2017
Significant progress in nonlinear and ultrafast optics has recently opened new and exciting opportunities for terahertz (THz) science and technology, which require the development of reliable THz sources, detectors, and supporting devices. In this work, we demonstrate the first solid-state technique for the coherent detection of ultra-broadband THz pulses (0.1-10 THz), relying on the electric-field-induced second-harmonic generation in a thin layer of ultraviolet fused silica. The proposed CMOS-compatible devices, which can be realized with standard microfabrication techniques, allow us to perform ultra-broadband detection with a high dynamic range by employing probe laser powers and bias v…
Cuando la historia está presente: Argumentos a favor de la sociología histórica
2019
Sociology and history have maintained a discontinuous relationship and a permanent discussion. Classical sociology is intrinsically historical, but after the first theoretical synthesis the dialogue between both disciplines was extinguished and it has often been necessary to defend the need for the historical view in sociology from the margins of the dominant paradigm. However, as a specialty or subdiscipline, historical sociology has consolidated its own academic space and a strong theoretical, methodological and conceptual body. In Spain this process of institutionalization has not yet success. In this article we expose a few arguments in defense of historical sociology, both theoretical …
Alkylsilyl compounds as enablers of atomic layer deposition: analysis of (Et3Si)3As through the GaAs process
2016
A new chemistry has been developed to deposit GaAs, the quintessential compound semiconductor. The ALD process is based on a dechlorosilylation reaction between GaCl3 and (Et3Si)3As. Characteristic ALD growth was demonstrated, indicating good applicability of the alkylsilyl arsenide precursor. ALD of GaAs produced uniform, amorphous and stoichiometric films with low impurity content. This was done with saturating growth rates and an easily controlled film thickness. Crystallization was achieved by annealing. Even though the growth rate strongly decreased with increasing deposition temperature, good quality film growth was demonstrated at 175 to 200 °C, indicating the presence of an ALD wind…
Curs de consolidació comptable
2013
Aquest document tracta l'elaboració de la informació comptable que han d'elaborar els grups empresarials i que es denomina comptes anuals consolidats. Per fer-ho, i partint de la necessària referència a les normes comptables de rang internacional que han inspirat el desenvolupament normatiu d'aquesta matèria a Espanya, s'analitzaran els aspectes tècnics de les normes per a la formulació dels comptes anuals consolidats vigents al nostre país. En virtut de les normes esmentades, aquelles societats que exerceixen un control sobre unes altres estan obligades a formular, a més dels seus comptes anuals individuals, els denominats comptes consolidats, amb aplicació d’uns mètodes i tècniques concre…
Increased conformational rigidity of humic substances by oxidative biomimetic catalysis
2005
A synthetic water-soluble meso-tetra(2,6-dichloro-3-sulfonatophenyl)porphyrinate of iron(III) chloride, Fe(TDCPPS)Cl, was employed as a biomimetic catalyst in the oxidative coupling of terrestrial humic materials. High-performance size-exclusion chromatography (HPSEC), solid-state nuclear magnetic resonance (CPMAS-(13)C NMR), electron paramagnetic resonance (EPR), and diffuse reflectance infrared spectroscopy (DRIFT) were used to follow conformational and structural changes brought about in different humic materials by the oxidative coupling. Increase in apparent weight-average molecular weight (Mw(a)) occurred invariably for all humic substances with the oxidative polymerization catalyzed …
Agere 'ex asse in solidum' e agere 'pro parte in solidum'. Per un'interpretazione di Venul. 7 stip. D. 10, 2, 7
2020
The paper proposes a revised analysis of D. 10.2.7 (Venul. 7 stip.), from which it seems reasonable to suggest that Venuleius discussed a particular kind of co-inheritance: the coniunctim attribution of a hereditas or an inheritance quota regarding two heirs. The substantially classical text, which can be glimpsed therein, offers evidence of the coexistence of different patterns of co-inheritance in classical private Roman law.