Search results for "graphe"
showing 10 items of 563 documents
Asymptotic behaviour of mixed-type circuits. Delay time predicting
1991
In the preceding chapter we have shown that the delay time problem in integrated circuits leads us to consider mixed-type circuits with distributed elements described by Telegraph Equations and lumped resistive and capacitive elements (Figure 4.5). Moreover, the well-posedness of the mathematical model (P(B, V0)) = (E) + (BC) + (IC) has been studied, various conditions for the existence, uniqueness and L2stability of different kind of solutions being formulated.
Partitionability, coverability and colorability in graphs
2014
Our research are about graph coloring with distance constraints (packing coloring) or neighborhood constraints (Grundy coloring). Let S={si| i in N*} be a non decreasing sequence of integers. An S-packing coloring is a proper coloring such that every set of color i is an si-packing (a set of vertices at pairwise distance greater than si). A graph G is (s1,... ,sk)-colorable if there exists a packing coloring of G with colors 1,... ,k. A Grundy coloring is a proper vertex coloring such that for every vertex of color i, u is adjacent to a vertex of color j, for each ji. These results allow us to determine S-packing coloring of these lattices for several sequences of integers. We examine a cla…
Tuning the Pseudospin Polarization of Graphene by a Pseudomagnetic Field.
2016
One of the intriguing characteristics of honeycomb lattices is the appearance of a pseudo-magnetic field as a result of mechanical deformation. In the case of graphene, the Landau quantization resulting from this pseudo-magnetic field has been measured using scanning tunneling microscopy. Here we show that a signature of the pseudo-magnetic field is a local sublattice symmetry breaking observable as a redistribution of the local density of states. This can be interpreted as a polarization of graphene's pseudospin due to a strain induced pseudo-magnetic field, in analogy to the alignment of a real spin in a magnetic field. We reveal this sublattice symmetry breaking by tunably straining grap…
LOMO sapiens: de la photographie
2015
Une des questions les plus fréquentes, dans les recherches sur la photographie, est liée à la valeur de médiation de l’image et donc au rapport qu’elle entretient avec la soi-disant réalité. D’un côté, la certitude de la présence devant l’objectif de ce que nous voyons représenté, une copie du monde excluant la nécessité d’un code pour être comprise, de l’autre, l’imposition d’un point de vue situé dans le temps et l’espace qui, par ces choix obligés, porte en soi le germe d’une stratégie de la communication. La sémiotique devient ainsi l’instrument pour analyser ces stratégies, pour rechercher des signifiés plus ou moins cachés, en démontant l’évidence supposée de l’image photographique. D…
Oxidized graphene in ionic liquids for assembling chemically modified electrodes: a structural and electrochemical characterization study
2012
Dispersions of graphene oxide (GO) nanoribbons in ionic liquids, ILs (either 1-butyl-3-methylimidazolium chloride (BMIM-Cl-) or 1-butylpyridinium chloride (-Bupy-Cl-)) have been used to assemble modified screen printed electrodes (SPEs). The graphene oxide/ionic liquid dispersions have been morphologically and structurally characterized by the use of several techniques: X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared (FT-IR) spectroscopy, high-resolution-transmission electron microscopy (HR-TEM). The assembled modified SPEs have then been challenged with various compounds and compared to several electro-active targets. In all cases high peak currents were detected, as wel…
Graphene oxide containing hyaluronic acid based nanogels for the potential treatment of colorectal cancer
2017
Here, we reported the production of graphene oxide (GO) containing nanogels produced by a top-down procedure employing as a starting biomaterial an amino derivative of hyaluronic acid named HA-EDA. This derivative was reacted, in the presence of single layer GO, with α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide-((2-aminoethyl)-carbamate)-divinyl sulfone (PHEA-DVS) employed as a macromolecular crosslinking agent. The so obtained hydrogel was homogenized by ultra-turrax and high pressure homogenizer and nanogels with Z-average of 390 nm and PDI of 0.22 were obtained. These nanogels were employed to incorporate Irinotecan (IT), an antitumor drug used in the treatment of colorectal carcinoma. It …
Thermally induced doping in controlled atmosphere on Graphene
2017
Since its experimental breakthrough discovery in 2004, Graphene (Gr) paved the way for the study of the "flatland" of two dimensional (2D) materials. These systems are an emerging topic of interest in solid state physics and amterial sciences, but nont only, and today count a family of monoatomic layer of C atoms in hexgonal honey comb crystalline structure.
Oded Ezer: Tipocriaturas
2012
Oded Ezer, Israeli type and graphic designer sui generis, has received numerous international awards in recent years, such as awards, participation in congresses and workshops, and has seen his first monograph be born (AA.VV., Oded Ezer. Typographer's Guide to the Galaxy, Gestalten, Berlin, 2009), all elements that have rapidly consolidated the recognition and the knowledge of his work and his transversal and interdisciplinary modus operandi. But among these was a monographic exhibition in which all his work, both professional and experimental, was exhibited. The void was filled at the end of 2011 by "Oded Ezer: Tipocriaturas", not one but two exhibitions entirely dedicated to him in Brazil…
Wet electrospinning-aided self-assembly of multifunctional GO-CNT@PCL core-shell nanocomposites with spider leg bioinspired hierarchical architectures
2022
We report a fast route enabling the multiscale design of nanohybrid structures comprising a 3D fibrous network of polycaprolactone (PCL) wrapped by graphene oxide (GO) sheets onto which carbon nanotube (CNT) brushes are anchored. The method relies on electrospinning PCL solutions onto a suspension of GO and CNTs in ethanol. Self-assembly is due to electrostatic wrapping of GO sheets around PCL fibers and 7C-7C stacking between GO and CNTs. Hierarchical architecture and nanopatterned surface allow gathering the starting properties of PCL, GO and CNTs into lightweight (99% porosity) yet robust (1575% stiffness improvement), amphiphilic monoliths that can remove methylene blue and/or methyl or…
An innovative route to prepare in situ graded crosslinked PVA graphene electrospun mats for drug release
2022
We present a fast, one step method to obtain PVA/graphene/chlorhexidine nanofibrous membranes, with a crosslinking gradient along their cross-section. Briefly, polymeric solutions were electrospun onto a heated plate, enabling the in situ crosslinking of PVA macromolecules. Of course, the crosslinking degree of such structures was found to decrease upon the distance from the plate during deposition. The outcomes reveal the crucial role of graphene, capable of promoting heat transfer throughout the entire structure, thus leading to 70-80% crosslinking degrees and preventing delamination issues. Such membranes were compared to untreated and oven thermally treated ones, and a robust relationsh…