Search results for "Methods"
showing 10 items of 4526 documents
Ab initio calculation of wurtzite‐type GaN nanowires
2007
Ab initio calculations of wurtzite-type GaN nanowires have been performed using density functional theory. Different shapes of nanowires of with similar diameters of around 2 nm have been considered to determine the stability of the structures. The quantitative similarities in the local properties obtained and dangling bond energies of nanowires and bulk surfaces have lead to a simple model model for a calculation of effective Young's modulus of nanowires of arbitrary diameters and shapes. The size dependence of the Young's modulus reveals a softening of GaN nanowires with the decrease of the diameter. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopic Investigation of the System TeCl4/[NEt4]PF6 in Solution and the Crystal Structure of [NEt4]2[Te2Cl10].
2005
Solutions containing TeCl 4 and [NEt 4 ][PF 6 ] in CH 2 Cl 2 were investigated by means of UV/vis and NMR spectroscopy in order to study the complex chemistry of TeCl 4 with the [PF 6 ] - anion. The results show formation of [TeCl 5 ] - and strong interactions of [PF 6 ] - with a tellurium containing species, presumably [TeCl 3 ] + . The life time of the Te I V -PF 6 complex is long enough to give different signals in the 1 9 F NMR spectrum of a solution containing excess [PF 6 ] - . Even a fivefold excess of Cl - ions over [PF 6 ] - does hardly lead to a dissociation of [TeCl 3 ...PF 6 ]. Crystals of [NEt 4 ] 2 [Te 2 Cl 1 0 ] were obtained from a 4:1 solution of [NEt 4 ]PF 6 and TeCl 4 in …
Electron Crystallography on Polymorphs
2006
Structure analysis via electron diffraction in combination with x-ray powder diffraction and simulation methods has been performed on single crystals of small organic molecules which form polymorphs. For two different examples of pigments and non-linear optical active material data collection, cell parameter and space group determination, structure analysis and refinement are discussed.
A 'Butterfly'-shaped Water Tetramer in a Cu4 Complex Supported by a Hydrazone Ligand: Synthesis, Crystal Structure, Magnetic Properties, and Quantum …
2009
A potentially tetradentate NOOO donor hydrazone ligand, LH2 (condensation product of benzhydrazide with O-vanillin) generates a tetranuclear CuII complex [Cu4(L)4]·4H2O (1), whose void spaces are occupied by water tetramers presenting a ‘butterfly’ conformation with the highest dihedral angle reported to date, as revealed by its X-ray crystal structure. 1 has also been characterized using various spectroscopic techniques, including IR, UV-vis, and elemental analysis. Variable temperature magnetic susceptibility measurements reveal the presence of moderate antiferromagnetic intra-tetramer coupling between the four CuII centres connected through simple oxo groups of the hydrazone ligand with…
Mesures, développement : le statut de la créativité en question
2016
Les particularités inhérentes à la créativité en tant que compétence transversale, analysées à partir d’une revue de littérature en psychologie et sociologie sur la mesure, le développement et les effets de la créativité, semblent lui conférer un statut restreint au sein du système éducatif français. D’une part, les incertitudes autour des effets à long terme de la créativité, tout comme la logique adéquationniste structurant l’organisation scolaire, maintiennent cette compétence à l’écart des principales finalités assignées au système éducatif français. D’autre part, celui-ci n’est pas outillé pour la mesurer, étant donné que ses méthodes d’évaluation ne permettent pas d’appréhender cette …
Timing techniques applied to distributed modular high-energy astronomy: the H.E.R.M.E.S. project
2021
The HERMES-TP/SP (High Energy Rapid Modular Ensemble of Satellites -- Technologic and Scientific Pathfinder) is an in-orbit demonstration of the so-called distributed astronomy concept. Conceived as a mini-constellation of six 3U nano-satellites hosting a new miniaturized detector, HERMES-TP/SP aims at the detection and accurate localisation of bright high-energy transients such as Gamma-Ray Bursts. The large energy band, the excellent temporal resolution and the wide field of view that characterize the detectors of the constellation represent the key features for the next generation high-energy all-sky monitor with good localisation capabilities that will play a pivotal role in the future …
The HERMES-Technologic and Scientific Pathfinder
2020
HERMES-TP/SP (High Energy Rapid Modular Ensemble of Satellites Technologic and Scientific Pathfinder) is a constellation of six 3U nano-satellites hosting simple but innovative X-ray detectors, characterized by a large energy band and excellent temporal resolution, and thus optimized for the monitoring of Cosmic High Energy transients such as Gamma Ray Bursts and the electromagnetic counterparts of Gravitational Wave Events, and for the determination of their positions. The projects are funded by the Italian Ministry of University and Research and by the Italian Space Agency, and by the European Union Horizon 2020 Research and Innovation Program under Grant Agreement No. 821896. HERMES-TP/S…
Care and reunification in a Cape Verdean family: Changing articulations of family and legal ties
2018
This article looks at the interaction between transnational family relationships, on the one hand, and family-related immigration policies, on the other. Taking the conflicting concerns that arose between administrative decision-makers and family members during an attempt to reunite a Cape Verdean family spread across several countries as an example, the questions of what ‘family’ means, what relationships are included and the nature of the relationships involved answered differently by different actors will be shown. The article discusses the way in which the regulation of transnational mobility according to specific categories of eligibility is giving social ties a concrete legal form whi…
Immunoanalytical approaches for the control of xenobiotics and biotoxins in food
2020
[ES] El control efectivo de la calidad y seguridad de los alimentos requiere de métodos analíticos que garanticen la determinación fiable de cualquier sustancia potencialmente perjudicial para el consumidor que pueda estar presente en el alimento antes de su distribución y comercialización. Una de las aproximaciones analíticas que contribuye a garantizar este objetivo engloba una serie de técnicas que tienen en común la utilización de anticuerpos como elementos esenciales para la detección del analito diana, y que en conjunto reciben el nombre de métodos inmunoquímicos. Este artículo pretender aportar una visión básica de los principios bioquímicos subyacentes a estas tecnologías y cuáles…
El exilio en primera persona. Un análisis del film Journal Inachevé de Marilú Mallet / Exile in the first person. An analysis of Journal Inachevé by …
2016
Este artículo estudia el proceso de recuperación de la cultura gallega en el exilio, la creación del proyecto empresarial del Laboratorio de Formas y la pervivencia del mismo, desde su puesta en marcha durante el franquismo hasta la democracia. Se aborda el importante papel que desempeñó para la recuperación de la memoria histórica gallega y se hace referencia a la difícil situación que está protagonizando. Palabras clave: Exilio, Patrimonio, Políticas de la Memoria, Cultura, Democracia. This article studies the process of recovery of Galician culture in exile, the creation of business project Laboratory methods and its survival, since Franco's dictatorship regime to democracy. It's an impo…