Search results for "OTU"

Preparazione e caratterizzazione di compositi polimerici funzionali a base di nanostrutture carboniose

Obiettivo di questo lavoro è la realizzazione di materiali nanocompositi polimerici utilizzando come matrice la resina epossidica commerciale Epikote828 e come filler nanotubi di carbonio (CNT) e nanoplacchette di grafene (GNP) e la caratterizzazione funzionale per applicarli come schermi per interferenze elettromagnetiche. Per correlare le proprietà funzionali alle proprietà morfologico-strutturali, i materiali sono stati analizzati mediante microscopia acustica a scansione (SAM) per valutare la dispersione del filler, spettroscopia Raman e per verificare risonanza magnetica nucleare in stato solido (ss-NMR) per studiare le interazioni filler-matrice e test di nanoindentazione per studiare…

Shape-dependency activity of nanostructured CeO2 in the total oxidation of polycyclic aromatic hydrocarbons

2013

11 figures, 2 tables.-- © 2012. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

Electrical Conduction in Carbon Nanotubes under Mechanical Deformations

2009

The enormous potential of carbon nanotubes (CNTs) as primary components in electronic devices and NEMS necessitates the understanding and predicting of the effects of mechanical deformation on electron transport in CNTs. In principle, detailed atomic/electronic calculations can provide both the deformed configuration and the resulting electrical transport behavior of the CNT. However, the computational expense of these simulations limits the size of the CNTs that can be studied with this technique and a direct analysis of CNTs of the dimension used in nano-electronic devices, particularly multi-wall CNTs (MWNTs), seems prohibitive at the present. Here a computationally effective mixed finit…

Simulation of the electromechanical behavior of multiwall carbon nanotubes.

2009

The enormous potential of carbon nanotubes (CNTs) as primary components in electronic devices and NEMS necessitates the understanding and predicting of the effects of mechanical deformation on electron transport in CNTs. In principle, detailed atomic/electronic calculations can provide both the deformed configuration and the resulting electrical transport behavior of the CNT. However, the computational expense of these simulations limits the size of the CNTs that can be studied with this technique, and a direct analysis of CNTs of the dimension used in nanoelectronic devices seems prohibitive at the present. Here a computationally effective mixed finite element (FE)/tight-binding (TB) appro…

Effect of size and deformation on polarizabilities of carbon nanotubes from atomic increments

2004

The interacting induced-dipole polarization model implemented in program POLAR is used for the calculation of the polarizability α. The method is tested with single-wall carbon nanotubes (SWNTs) as a function of radius and elliptical deformation. This work gives a partial success with the application of POLAR when compared with reference calculations performed with program PAPID. α follows a simple law. PAPID differentiates more effectively than POLAR among SWNTs with increasing radial deformation, a can be modified reversibly by external radial deformation. Different effective αeff are calculated for the atoms at the highest and lowest curvature sites. The difference between POLAR and PAPI…

From Well-Defined Carbon-Rich Precursors to Monodisperse Carbon Particles with Hierarchic Structures

2007

The creation of nanoscale particles with well-defined structures has long been considered as a promising approach to generate materials with novel properties. Carbonaceous nanoparticles (CNPs) with defined architectures, such as carbon nanotubes (CNTs), C60, carbon onions, carbon spheres, and carbon rods are particularly attractive owing to their unique electronic properties and many potential applications. At the same time, when these CNPs are regularly organized, additional functions appear. Such materials are believed to have hierarchic structures, in which the organization of the CNPs forms the first-order structure (FOS) and the configuration of the single CNP forms the secondor higher…

Recent advances in nanostructures and nanocrystals as signal-amplification elements in electrochemical cytosensing

2015

Abstract Considering the vital role of cells in life science and human health, cytosensors have become a hot research topic. Electrochemical cytosensors attract much attention. In this review, we discuss some recent efforts to construct novel and improved electrochemical cytosensors based on graphene, carbon nanotubes, some metal-nanoparticle composites, quantum dots, nanofibers and nanowires. In addition, we summarize examples of nanostructure applications in electrochemical cytosensing reported in the literature from 2009 to date, with their advantages and limitations, and stress their potential for future development. Also, we focus on the current surface-modification strategies with som…

Formation of linear Ni nanochains inside carbon nanotubes: Prediction from density functional theory

2013

Abstract First principles calculations have been performed to investigate the ground state properties of monoperiodic single-walled carbon nanotubes (CNTs) containing nanochain of aligned Ni atoms inside. Using the PBE exchange-correlation functional ( E xc ) within the framework of density functional theory (DFT) we predict the clusterization of Ni filaments in ( n ,0) CNTs for n ⩾  9 and for ( n , n ) CNTs for n ⩾  6. The variations in formation energies obtained for equilibrium defective nanostructures allow us to predict the most stable Ni@CNT compositions. Finally, the electronic charge redistribution has been calculated in order to explore intermolecular properties leading to stronger…

Single Out-of-Resonance Dielectric Nanoparticles as Molecular Sensors.

2021

Light scattering from single nanoparticles and nanostructures is a commonly used readout method for nanosensors. Increasing the spectral sensitivity of resonant nanosensors to changes in their local surrounding has been the focus of many studies. Switching from spectral to intensity monitoring allows one to investigate nonresonant or out-of-resonance dielectric nanoparticles. Here, we systematically compared such dielectric silica nanoparticles with plasmonic gold nanorods by deriving analytical expressions and by performing experiments. The experiments show a similar sensitivity for the detection of an adsorbate layer for both particle types, which is in good agreement with theory. The fla…

Preparation of Graphene Nanoribbons (GNRs) as an Electronic Component with the Multi-walled Carbon Nanotubes (MWCNTs)

2015

Abstract Carbon nanotubes (CNTs) have a well-defined nanostructure to exhibit high electrical conductivity and chemical stability, and have been used as an advanced material to make electrodes of super-capacitor. Graphene nanoribbons (GNRs), as manufactured by unzipping the CNTs, have more flexible adjustable electrical properties than CNTs, and are regarded an even more promising material for super-capacitor electrodes. This paper presented a series of attempts to prepare GNRs by chemically treating multi-walled carbon nanotubes (MWCNTs); this is, an Oxidation-Reduction method was tried to make GNRs by unzipping MWCNTs longitudinally. Efforts were made in various trials to find conditions …