Search results for " materiale"
showing 10 items of 139 documents
Forme del tempo
2009
Anomalous Slowdown of Polymer Detachment Dynamics on Carbon Nanotubes
2019
The "wrapping" of polymer chains on the surface of carbon nanotubes allows one to obtain multifunctional hybrid materials with unique properties for a wide range of applications in biomedicine, electronics, nanocomposites, biosensors, and solar cell technologies. We study by means of molecular dynamics simulations the force-assisted desorption kinetics of a polymer from the surface of a carbon nanotube. We find that, due to the geometric coupling between the adsorbing surface and the conformation of the macromolecule, the process of desorption slows down dramatically upon increasing the windings around the nanotube. This behavior can be rationalized in terms of an overdamped dynamics with a…
Gold Nanoparticle-Assisted Virus Formation by Means of the Delivery of an Oncolytic Adenovirus Genome
2020
[EN] Oncolytic adenoviruses are a therapeutic alternative to treat cancer based on their ability to replicate selectively in tumor cells. However, their use is limited mainly by the neutralizing antibody (Nab) immune response that prevents repeated dosing. An alternative to facilitate the DNA access to the tumor even in the presence of anti-viral Nabs could be gold nanoparticles able to transfer DNA molecules. However, the ability of these nanoparticles to carry large DNA molecules, such as an oncolytic adenovirus genome, has not been studied. In this work, gold nanoparticles were functionalized with different amounts of polyethylenimine to transfer in a safe and efficient manner a large on…
Estudios previos a la intervención en el patrimonio arquitectónico. El caso de la iglesia parroquial de San Pedro en la Pobla de Benifassà (Castellón)
2002
Cualquier tipo de intervención en el patrimonio arquitectónico requiere en primera instancia de un conocimiento del objeto de esta acción. Se debe abordar cuantos más aspectos y características del edificio para ajustarse correctamente con nuestra intervención a sus problemas reales. En su primera parte, el texto explica el funcionamiento general de los distintos capítulos de un estudio previo; en la segunda, se expone un caso real de estudio previo desarrollado por los autores del artículo; en la tercera parte, se da una explicación técnica sobre los análisis estratigráficos de las fábricas como una metodología para profundizar en el conocimiento de la historia de la arquitectura.
ZrTiO4 materials obtained by spark plasma reaction-sintering
2014
Zirconium titanate (ZrTiO4), have many attractive properties such as high resistivity, high dielectric constant, high permittivity at microwave frequencies and excellent temperature stability for microwave properties. Zirconium titanate dense materials are proposed for many structural applications, but fully reacted and completely dense pieces are difficult to obtain by conventional routes. In this work, fully dense zirconium titanate materials (∼98%) were obtained at lower temperatures (1300-1400 C) and short processing time by non-conventional technique; spark plasma-reaction sintering (SPRS). Homogeneous and stable starting powders mixture with the adequate composition was prepared from …
Order-Order Phase Transitions Induced by Supercritical Carbon Dioxide in Triblock Copolymer Thin Films
2019
We study the influence of supercritical carbon dioxide (scCO2) on the phase behavior of a cylinder-forming polystyrene-block-polybutadiene-b-polystyrenetriblock copolymer thin film. Solvent annealing with scCO2 can produce patterns with long-range order but these structures become unstable for thin films with small thicknesses. These results are in good agreement with self-consistent mean field calculations, which indicate that a drying transition occurs for thicknesses below the radius of gyration of the molecule.After decompression and solvent extraction, the initially swollen polymer nanostructure suffers a strong reduction in the average domain spacing, which has a deleterious effect on…
Cathodoluminescence and photoluminescence study of plastically deformed ZnTe bulk single crystals
2001
Samples of zinc telluride bulk single crystals, which were deformed in uniaxial compression, have been studied by photoluminescence (PL) and cathodoluminescence (CL). As a particular feature the deformed samples present a PL emission band peaked at 603 nm, whose intensity increases as the plastic deformation does. This band is related to the density of dislocations produced during the interaction of slip systems. This hypothesis is supported by CL images. which reveal the activation of the successive slip systems corresponding to different levels of deformation.
On the half-metallicity of Co2FeSi Heusler alloy: Point-contact Andreev reflection spectroscopy andab initiostudy
2013
Co2FeSi, a Heusler alloy with the highest magnetic moment per unit cell and the highest Curie temperature, has largely been described theoretically as a half-metal. This conclusion, however, disagrees with point contact Andreev reflection (PCAR) spectroscopy measurements, which give much lower values of spin polarization, P. Here, we present the spin polarization measurements of Co2FeSi by the PCAR technique, along with a thorough computational exploration, within the DFT and a GGA+U approach, of the Coulomb exchange U parameters for Co and Fe atoms, taking into account spin-orbit coupling. We find that the orbital contribution (mo) to the total magnetic moment (mT) is significant, since it…
Double pion photoproduction in nuclei
1995
The inclusive A(gamma,pi+ pi-)X reaction is studied theoretically. A sizeable enhancement of the cross section is found, in comparison with the scaling of the deuteron cross section (sigma_deuteron * A/2). This enhancement is due to the modifications in the nuclear medium of the gamma N ----> pi pi N amplitude and the pion dispersion relation. The enhancement is found to be bigger than the one already observed in the (pi,pi pi) reaction in nuclei.
Quark effects, meson-exchange currents and background in the d(e,e'p)delta reaction
1994
[EN] We have studied in detail the cross section for the d(e, e'p)Delta reaction leading to the emission of a fast nucleon and a Delta at rest, which has been advocated as a tool to investigate quark effects in nuclei. We find that ordinary meson-exchange currents mechanisms dominate the quark-exchange effects in the region of excitation of the Delta and could be competitive at higher energies. Furthermore, at these higher energies, the small cross sections for the quark signal, together with the presence of a background about one order of magnitude bigger than the quark signal, make in any case the extraction of information about quark-exchange currents effects extraordinarily difficult.