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Production scientifique
(295) Production(s) de l'année 2019
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Biophysical modeling of translation
Auteur(s): Walter J.-C.
Conférence invité: Translation Control in Cancer (Montpellier, FR, 2019-05-20)
Ref HAL: hal-02137958_v1
Exporter : BibTex | endNote
Résumé: W propose biophysical approach to offer a mechanistic view of translational. The goal is to be able to use Ribo-sequencing data to estimate biophysical parameters of translation like: initiation, elongation and termination rates in order to make prediction on the cancerous cell phenotype.
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Electrochemical Capacitance and Transit Time in Quantum Hall Conductors
Auteur(s): Delgard A., Chenaud B., Mailly Dominique, Gennser Ulf, Ikushima Kenji, Chaubet C.
(Article) Publié:
Physica Status Solidi B, vol. p.1800548 (2019)
Ref HAL: hal-02137172_v1
DOI: 10.1002/pssb.201800548
WoS: 000473612400011
Exporter : BibTex | endNote
Résumé: In a two dimensional electron gas, low energy transport in presence of a magnetic field occurs in chiral 1D channels located on the edge of the sample. In the AC description of quantum transport, the emittance determines the amplitude of the imaginary part of the admittance, whose sign and physical meaning are determined by the sample topology: a Hall bar is inductive while a Corbino ring is capacitive. In this article, the perfect capacitive character of Corbino samples in the quantum Hall effect regime is shown. A vanishing conductance and an electrochemical capacitance which depends on the density of states of 1D channels are measured. Our samples have no gate, neither on the side nor on the top, and the inner capacitances are measured. The transit time of electrons across the device is obtained and the drift velocity of carriers is deduced.
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Magnetic-TEGFET: Transistor Without a Gate
Auteur(s): Raymond A., Chaubet C., Delgard A., Chenaud B., Cavanna Antonella, Harmand Jean Christophe, Zawadzki Wlodzimierz
(Article) Publié:
Physica Status Solidi B, vol. p.1800509 (2019)
Ref HAL: hal-02137158_v1
DOI: 10.1002/pssb.201800509
WoS: 000473612400001
Exporter : BibTex | endNote
Résumé: Low‐temperature current–voltage characteristics of n‐type GaAs/GaAlAs quantum wells delta‐doped in GaAs channel with Be acceptors are studied in the presence of a magnetic field. Negatively charged acceptor ions localize 2D conduction electrons by a combined effect of a quantum well and magnetic field parallel to the growth direction. In acceptor‐doped samples, the Hall electric field plays the role of the gate voltage. It is shown that at magnetic fields as weak as 1.5 T (or higher), the drain current reaches a constant value independent of the drain voltage. This phenomenon is due to the electron localization resulting in the decrease of conducting electron density in the crossed‐field configuration. The above special behavior of acceptor‐doped GaAs/GaAlAs heterostructures is exploited to realize a device called Magnetic‐TEGFET (Magnetic Two‐dimensional Electron Gas Field Effect Transistor) operating at low temperatures. The elimination of the gate in the studied transistor suppresses the gate‐to‐drain leakage current, which, in the standard TEGFETs, results in the electronic shot noise.
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Comprehensive model of the optical spectra of carbon nanotubes on a substrate by polarized microscopy
Auteur(s): Monniello L., Tran H.-N., Vialla R., Prevot G., Tahir S., Michel T., Jourdain V.
(Article) Publié:
Physical Review B, vol. 99 p.115431 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-02134571_v1
DOI: 10.1103/PhysRevB.99.115431
WoS: 000462895200004
Exporter : BibTex | endNote
Résumé: Polarized optical microscopy and spectroscopy are progressively becoming key methods for the high-throughput characterization of individual carbon nanotubes (CNTs) and other one-dimensional nanostructures, on substrate and in devices. The optical response of CNTs on substrate in cross polarization experiments is usually limited by the polarization conservation of the optical elements in the experimental setup. We developed a theoretical model taking into account the depolarization by the setup and the optical response of the substrate. We show that proper modelization of the experimental data requires to take into account both noncoherent and coherent light depolarization by the optical elements. We also show how the nanotube signal can be decoupled from the complex reflection factor of the antireflection substrate, which is commonly used to enhance the optical contrast. Finally, we describe an experimental protocol to extract the depolarization parameters and the complex nanotube susceptibility, and how it can improve the chirality assignment of individual carbon nanotubes in complex cases.
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One-pot preparation of iron/alumina catalyst for the efficient growth of vertically-aligned carbon nanotube forests
Auteur(s): Roussey Arthur, Venier Nicolas, Fneich Hussein, Giardella Lucas, Pinaud Thomas, Tahir S., Pelaez-Fernandez Mario, Arenal Raul, Mehdi Ahmad, Jourdain V.
(Article) Publié:
Materials Science And Engineering: B, vol. 245 p.37-46 (2019)
Texte intégral en Openaccess :
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Organic–inorganic nanohybrid materials: Self-assembling and properties
Auteur(s): Bantignies J.-L., Le Parc R.
Conférence invité: Nanomaterials Applications Conference (NANOAPP19) (Ljubljana, SI, 2019-06-03)
Résumé: Over the past two decades significant efforts have been directed towards the elucidation of synthesis/structure/function correlations to guide the development of synthetic strategies for controlling the composition, size and shape of nanomaterials. In this context, organic–inorganic nanohybrids incorporating bridged silsesquioxanes have been of particular interest, due to their versatility and the structural control that can be achieved through independent modulation of the properties of the organic bridge and inorganic moieties. Such strategies have also been applied to the production of thin films on a variety of substrates, driven by the continuous need to develop new and enhanced materials with nanostructures engineered over multiple length scales for applications in electronics, optics, sensing, ferromagnetic, shape-selective membranes, etc.
In this talk, I will first present a fundamental study of the nanostructuring mechanisms of model hybrid silica. Our experimental investigation was performed using an in operando approach (vibrational spectroscopies under pressure, light diffusion, microscopy) coupled with DFT calculations. Parameters controlling the evolution of the system during sol−gel processing: supramolecular interactions, hydrolysis, polycondensation, and nucleation and growth of the hybrid solid in solution were investigated. The relation between structural properties and applications will be then highlighted1-4.
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