232 research outputs found
On graphs with no induced subdivision of
We prove a decomposition theorem for graphs that do not contain a subdivision
of as an induced subgraph where is the complete graph on four
vertices. We obtain also a structure theorem for the class of graphs
that contain neither a subdivision of nor a wheel as an induced subgraph,
where a wheel is a cycle on at least four vertices together with a vertex that
has at least three neighbors on the cycle. Our structure theorem is used to
prove that every graph in is 3-colorable and entails a polynomial-time
recognition algorithm for membership in . As an intermediate result, we
prove a structure theorem for the graphs whose cycles are all chordless
On graphs that do not contain a subdivision of the complete graph on four vertices as an induced subgraph
We prove a decomposition theorem for graphs that do not contain a subdivision of the complete graph on four vertices as an induced subgraph.Induced, subgraph, decomposition.
Aberration-free calibration for 3D single molecule localization microscopy
We propose a straightforward sample-based technique to calibrate the axial
detection in 3D single molecule localization microscopy (SMLM). Using
microspheres coated with fluorescent molecules, the calibration curves of
PSF-shaping- or intensity-based measurements can be obtained for any required
depth range from a few hundreds of nanometers to several tens of microns. This
experimental method takes into account the effect of the spherical aberration
without requiring computational correction.Comment: 8 pages, 2 figures. Submitted to Optics Letters on October 12th, 201
Detecting induced subgraphs
An s-graph is a graph with two kinds of edges : subdivisible edges and real edges. A realisation of an s-graphB is any graph obtained by subdividing subdivisible edges of B into paths of arbitrary length (at least one). Given an s-graph B, we study the decision problem Pi(B) whose instance is a graph G and whose question is "Does G contain a realisation of B as an induced subgraph ?".Detection, induced, subgraph.
On graphs that do not contain a subdivision of the complete graph on four vertices as an induced subgraph
URL des Documents de travail :http://ces.univ-paris1.fr/cesdp/CESFramDP2007.htmDocuments de travail du Centre d'Economie de la Sorbonne 2007.51 - ISSN : 1955-611XWe prove a decomposition theorem for graphs that do not contain a subdivision of the complete graph on four vertices as an induced subgraph.Nous donnons un théorème de décomposition pour les graphes ne contenant pas de subdivision du graphe complet sur quatre sommets en tant que sous-graphe induit
Phonon-Plasmon Interaction in Metal-Insulator-Metal Localized Surface Plasmon Systems
We investigate theoretically and numerically the coupling between elastic and
localized surface plasmon modes in a system of gold nanocylinders separated
from a thin gold film by a dielectric spacer of few nanometers thickness. That
system supports plasmon modes confined in between the bottom of the
nanocylinder and the top of the gold film, which arise from the formation of
interference patterns by short-wavelength metal-insulator-metal propagating
plasmon. First we present the plasmonic properties of the system though
computer-simulated extinction spectra and field maps associated to the
different optical modes. Next a simple analytical model is introduced, which
allows to correctly reproduce the shape and wavelengths of the plasmon modes.
This model is used to investigate the efficiency of the coupling between an
elastic deformation and the plasmonic modes. In the last part of the paper, we
present the full numerical simulations of the phononic properties of the
system, and then compute the acousto-plasmonic coupling between the different
plasmon modes and five acoustic modes of very different shape. The efficiency
of the coupling is assessed first by evaluating the modulation of the resonance
wavelength, which allows comparison with the analytical model, and finally in
term of time-modulation of the transmission spectra on the full visible range,
computed for realistic values of the deformation of the nanoparticle.Comment: 12 pages, 9 figure
Impact of Backbone fluorination on -conjugated polymers in organic photovoltaic devices: a review
Solution-processed bulk heterojunction solar cells have experienced a remarkable
acceleration in performances in the last two decades, reaching power conversion efficiencies above 10%. This impressive progress is the outcome of a simultaneous development of more advanced device architectures and of optimized semiconducting polymers. Several chemical approaches have
been developed to fine-tune the optoelectronics and structural polymer parameters required to reach
high efficiencies. Fluorination of the conjugated polymer backbone has appeared recently to be
an especially promising approach for the development of efficient semiconducting polymers. As a
matter of fact, most currently best-performing semiconducting polymers are using fluorine atoms in their conjugated backbone. In this review, we attempt to give an up-to-date overview of the latest results achieved on fluorinated polymers for solar cells and to highlight general polymer properties’ evolution trends related to the fluorination of their conjugated backbone
Impact of Backbone fluorination on -conjugated polymers in organic photovoltaic devices: a review
Solution-processed bulk heterojunction solar cells have experienced a remarkable
acceleration in performances in the last two decades, reaching power conversion efficiencies above 10%. This impressive progress is the outcome of a simultaneous development of more advanced device architectures and of optimized semiconducting polymers. Several chemical approaches have
been developed to fine-tune the optoelectronics and structural polymer parameters required to reach
high efficiencies. Fluorination of the conjugated polymer backbone has appeared recently to be
an especially promising approach for the development of efficient semiconducting polymers. As a
matter of fact, most currently best-performing semiconducting polymers are using fluorine atoms in their conjugated backbone. In this review, we attempt to give an up-to-date overview of the latest results achieved on fluorinated polymers for solar cells and to highlight general polymer properties’ evolution trends related to the fluorination of their conjugated backbone
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