Search results for "surface"

Preparation of Nd:YAG Nanopowder in a Confined Environment

2007

Nanopowder of yttrium aluminum garnet (YAG, Y3Al5O12) doped with neodymium ions (Nd:YAG) was prepared in the water/cetyltrimethylammonium bromide/1-butanol/n-heptane system. Aluminum, yttrium, and neodymium nitrates were used as starting materials, and ammonia was used as a precipitating agent. Coprecipitate hydroxide precursors where thermally treated at 900 degrees C to achieve the garnet phase. The starting system with and without reactants was characterized by means of the small-angle neutron scattering technique. The system, without reactants, is constituted by a bicontinuous structure laying near the borderline with the lamellar phase region. The introduction of nitrates stabilizes th…

Programmable surface-architectures derived from hybrid polyoxometalate-based clusters

2011

The exploration of the self-organization of a range of the polyoxometalate-based molecular structures reveals a diverse range of surface patterns and morphologies on solid substrates of technological interest, including methylated and hydroxylated silicon surfaces (namely, SiCH3 and SiOH). By exploiting the interplay between the intrinsic molecular properties and the surface chemistry as well as dynamic spatiotemporal phenomena (e.g., dewetting), we show that these systems can yield 0D, 2D, and 3D architectures via solution deposition at the solid surface, including nanodots, discs, lamellas, porous networks, and layer-by-layer assemblies. In general, we observed that layer-by-layer growth …

Surface modification of poly(ethylene-co-acrylic acid) with amino-functionalized silica nanoparticles

2011

In this work we studied the possibility to achieve a hybrid-surface through the modification, via a facile wet chemical process, of the surface of films of poly(ethylene-co-acrylic acid) (EAA) with amino-modified silica nanoparticles. Films of EAA were preliminarily activated by the introduction of -COCl groups on their surface. Silica nanoparticles were thereafter covalently bound on the polymeric surface as confirmed by FTIR, ATR-FTIR, XPS, NMR and SEM determinations. The nanoparticles formed a multilayer on the film surface and covered almost uniformly the whole film surface. Direct measurements of superficial amino groups by titration allowed us to detect a concentration of about 18 nmo…

Nanohybrid surface based on covalent linkage of amino-functionalized silica nanoparticles on EAA polymeric substrate

2011

Polyoxometalates complex architectures in thin films by exploiting physical and chemical processes at surfaces

2010

Optical Properties of III-V Nanowires and Their Application for Charge Transport and Single-Photon Emission

2012

This work covers the optical characterization of III-V semiconductor nanowires and their application for charge transport and for single-photon emission. InAs nanowires have been investigated by Raman scattering and PL spectroscopy. The possibility to grow nanowires with a crystal structure different from its bulk counterpart has aroused a lot of interest in their optical and electronic properties. Here, the optical phonon modes of wurtzite InAs nanowires have been studied by polarized Raman scattering. For the first time, Raman measurements on a single InAs nanowire have revealed the A1(TO) and E2h optical phonon modes of the wurtzite structure. Additional resonant Raman scattering experim…

Understanding "Islandness"

2023

Islandness is a contested concept, not just between disciplines but also cultures, entangled with what islands, island studies, and island identity are understood to be. The purpose of this article is to explore some of these different meanings, without necessarily unifying or reconciling them, with the aim of keeping multiple understandings of islandness in creative tension. We begin by considering islandness as smallness, recognizing that though many entry points into island studies relate to size in some way, what constitutes small is dependent on both context and worldview. Next, we consider islandness as culture, and the concept of island identity, which is expressed in varied forms. F…

Study of Intumescent Coatings Growth for Fire Retardant Systems in Naval Applications: Experimental Test and Mathematical Model

2022

Onboard ships, fire is one of the most dangerous events that can occur. For both military and commercial ships, fire risks are the most worrying; for this reason they have an important impact on the design of the vessel. The intumescent coatings react when heated or in contact with a living flame, and a multi-layered insulating structure grows up, protecting the underlying structure. In this concern, the aim of the paper is to evaluate the intumescent capacity of different composite coatings coupling synergistically modeling and experimental tests. In particular, the experiments have been carried out on a new paint formulation, developed by Colorificio Atria S.r.l., in which the active comp…

A Classification of Palermo Historical Centre Heritage based on the local seismic response

2009

A very high density of monumental heritage falls within Palermo Historical Centre, an area characterized by high variability of near surface geology and soil physical-mechanical properties on a very short distance scale, even few meters. So, neighboring heritage elements can have a totally different hazard exposition. Within a project regarding Palermo area (Project 7T7, Cluster 29, funded by Ministero dell’Università e della Ricerca, Italy) a very reliable high density stratigraphic-geotechnical dataset has been assembled, by means of a careful data reviewing process. This dataset has been stored in a Geographic Information System (GIS) application, named City-GIS, having all GIS functions…

Stick around: Cell–Cell Adhesion Molecules during Neocortical Development

2021

The neocortex is an exquisitely organized structure achieved through complex cellular processes from the generation of neural cells to their integration into cortical circuits after complex migration processes. During this long journey, neural cells need to establish and release adhesive interactions through cell surface receptors known as cell adhesion molecules (CAMs). Several types of CAMs have been described regulating different aspects of neurodevelopment. Whereas some of them mediate interactions with the extracellular matrix, others allow contact with additional cells. In this review, we will focus on the role of two important families of cell–cell adhesion molecules (C-CAMs), classi…