Search results for "element"
showing 10 items of 13601 documents
Delayed and In-beam Spectroscopy on Francium and Astatine Nuclei at the Proton Drip Line
2011
Delayed and in‐beam spectroscopy on francium and astatine nuclei at and beyond the proton drip line has been performed. In neutron deficient astatine nuclei a shift to deformed shapes as a function of decreasing neutron has been obtained. In neutron deficient francium isotope the same shift is evident.
Adsorption and Activation of Water on Cuboctahedral Rhodium and Platinum Nanoparticles
2017
Rh and Pt are widely used as the components in heterogeneous catalysts for multiple industrial applications. Because the metals are typically in the form of nanoparticles in real catalysts, it is important to carefully select models for the computational prediction of the catalytic properties. Here we report a first-principles study on the water activation, an important step in numerous catalytic reactions, using the finite-size Rh and Pt nanoparticle models and compare them to the extended surface models. We show that regardless of the model, adsorption and activation of water is practically identical for both metals, whereas the dissociation is energetically more favorable on Rh. The expe…
Government policy failure in public support for research and development
2014
peer-reviewed Promoting Research and Development (R&D) and innovative activity is a key element of the EU Lisbon Agenda and is seen as playing a central part in stimulating economic development. In this paper we argue that, even allowing for benevolent policy-makers, informational asymmetries can lead to a misallocation of public support for R&D, hence government policy failure, with the potential to exacerbate preexisting market failures. Initially, we explore alternative allocation mechanisms for public support, which can help to minimize the scale of these government policy failures. Of these mechanisms (grants, tax credits, or allocation rules based on past performance), our results sug…
The role of temperament in children's affective and behavioral responses in achievement situations
2013
Abstract Although students' affects and behaviors in achievement situations have been shown to be influenced by their previous learning experiences, less is known about how they relate to students' dispositional characteristics, such as temperament. This study examined to what extent children's temperament is related to their affective and behavioral responses in achievement situations. Teachers rated first-graders' ( n = 153) temperamental characteristics in the Fall semester. Children's active task avoidance, anxiety, and helplessness were rated in test situations in the Fall and Spring semesters. The results showed that the more easily distracted the children were, the more task avoidan…
L'analisi dei testi letterari per l'infanzia
2011
Nell’attività di insegnamento la promozione della lettura è un compito fondamentale, un compito affascinante che comporta lo stimolare, l’orientare, il riflettere per far riflettere. L’insegnante che “educa” l’alunno a leggere deve essere in grado di accompagnare nel cammino di questa avventura, in modo che l’opera letteraria diventi per il giovane strumento di crescita, di riflessione, di interiorizzazione, di godimento. Per scegliere libri interessanti e validi è necessario che, oltre all’intuizione ed alla sensibilità letteraria, gli insegnanti posseggano una specifica competenza. Nell’ambito dell’insegnamento di Letteratura per l’infanzia, all’interno del corso di laurea in Scienze dell…
Finite element multi-scale modeling of the failure mechanisms in a 3D woven composite
2013
International audience
Formation of Si/SiO2 Luminescent Quantum Dots From Mesoporous Silicon by Sodium Tetraborate/Citric Acid Oxidation Treatment
2019
We propose a rapid, one-pot method to generate photoluminescent (PL) mesoporous silicon nanoparticles (PSiNPs). Typically, mesoporous silicon (meso-PSi) films, obtained by electrochemical etching of monocrystalline silicon substrates, do not display strong PL because the silicon nanocrystals (nc-Si) in the skeleton are generally too large to display quantum confinement effects. Here we describe an improved approach to form photoluminescent PSiNPs from meso-PSi by partial oxidation in aqueous sodium borate (borax) solutions. The borax solution acts to simultaneously oxidize the nc-Si surface and to partially dissolve the oxide product. This results in reduction of the size of the nc-Si core …
Applications and non-idealities of submicron Al–AlOx–Nb tunnel junctions
2016
We have developed a technique to fabricate sub-micron, 0.6µm×0.6µm Al-AlOx-Nb tunnel junctions using a standard e-beam resist, angle evaporation and double oxidation of the tunneling barrier, resulting in high quality niobium, as determined by the the high measured values of the critical temperature TC ∼ 7.5 K and the gap ∆ ∼ 1.3 meV. The devices show great promise for local nanoscale thermometry in the temperature range 1 - 7.5 K. Electrical characterization of the junctions was performed at sub-Kelvin temperatures both with and without an external magnetic field, which was used to suppress superconductivity in Al and thus bring the junction into a normal-metal-insulator-superconductor (NI…
Environmental Effects on Mechanical, Thermophysical and Electrical Properties of Epoxy Resin Filled with Carbon Nanofillers
2019
The aim of this work was to establish the effect of environmental factors (moisture and temperature) on some mechanical, electrical and thermal properties of epoxy-based composites filled with carbon nanofillers: nanotubes (CNT), nanofibers (CNF) and hybrid nanofiller (nanotubes/nanofibers in the ratio 1:1) and to reveal the most environmentally stable NC. First, the nanocomposites (NC) containing different nanofiller contents were prepared to evaluate electrical percolation threshold and to choose NC at certain electrical conductivity for further characterization of the physical properties in initial state and during/after environmental ageing. The environmental ageing consisted of water a…