44 research outputs found
High-Sensitivity Sensor Using C<sub>60</sub>-Single Molecule Transistor
No full textInternational audienc
Mildly-doped polythiophene with triflates for molecular recognition
No full textInternational audienceOrganic semiconductors have enough molecular versatility to feature chemo-specific electrical sensitivity to large families of chemical substituents via different intermolecular bonding modes. This study demonstrates that one single conducting polymer can be tuned to either discriminate water-, ethanol-or acetone-vapors, on demand, by changing the nature of its dopant. Seven triflate salts differ from mild to strong p-dopant on poly(3hexylthiophene) sensing micro-arrays. Each material shows a pattern of conductance modulation for the polymer which is reversible, reproducible, and distinctive of other gas exposures. Based on principal component analysis, an array doped with only two different triflates can be trained to reliably discriminate gases, which re-motivates using conducting polymers as a class of materials for integrated electronic noses. More importantly, this method points out the existence of tripartite donor-acceptor charge-transfer complexes responsible for chemospecific molecular sensing. By showing that molecular acceptors can have duality to p-dope semiconductors and to coordinate donor gases, such behavior can be used to understand the role of frontier orbital overlapping in organic semiconductors, the formation of charge-transfer complexes via Lewis acid-base adducts in molecular semiconductors
Simulation and Modelling of the Write/Erase Kinetics and the Retention Time of Single Electron Memory at Room Temperature
No full textElectrical study of pentacene-based metal-semiconductor-metal structure: Schottky barrier and active layer thickness effects
No full textInternational audienceThe impact of electrodes and active layer thickness on the current-voltage characteristics of Au/Pentacene/Al structure was studied using a physicallybased 2-D simulation by solving Poisson's, continuity, and drift diffusion equations. The main parameters required for simulation are extracted from the logarithmic representation of experimental current-voltage curves. The simulation results produce an excellent overlapping with the experimental data after including parameters previously found in our model. Finally, the simulation was used to better understand the physical processes together with mechanisms governing the efficiency of the device under investigation and to have a predictive behavior
The Effectiveness of Thematic Mapping in the Process of Learning in Schools
No full textThe reliable handling of graphically complex cartographical illustrations requires methodic skills from the users as well as high qualifications on the part of the map author. A very important aspect in this context is the suitable thematic mapping of visualization in school lessons. The results of an empirical survey show that the structural complexity of maps has got a considerable influence on the perceptive capacity. The adaption of complex contents depends on the previous knowledge of the mapreader.Peer Reviewe
Steady vs. Dynamic Contributions of Different Doped Conducting Polymers in the Principal Components of an Electronic Nose’s Response
No full textInternational audienceMultivariate data analysis and machine-learning classification become popular tools to extract features without physical models for complex environments recognition. For electronic noses, time sampling over multiple sensing elements must be a fair compromise between a period sufficiently long to output a meaningful information pattern, and sufficiently short to minimize training time for practical applications. Particularly when reactivity's kinetic differs from thermodynamic in sensitive materials, finding the best compromise to get the most from data is not obvious. Here, we investigate on the influence of data acquisition to improve or alter data clustering for molecular recognition on a conducting polymer electronic nose. We found out that waiting for sensing elements to reach their steady state is not required for classification, and that reducing data acquisition down to the first dynamical information suffice to recognize molecular gases by principal component analysis with the same materials. Especially for online inference, this study shows that a good sensing array is no array of good sensors, and that new figure-of-merits shall be defined for sensing hardware aiming machine-learning pattern-recognition rather than metrology
Fast terminal sliding mode tracking control of nonlinear uncertain mass–spring system with experimental verifications
No full textIn this article, a fast terminal sliding mode control technique is used for robust tracking control of a nonlinear uncertain mass–spring system in the existence of external perturbation. This system is considered as a benchmark problem in the flexible joint mechanisms. The joints flexibility in the robotic systems creates one of the most significant sources of parametric uncertainties. The theory of Lyapunov stability is used for the formulation of the proposed control method, and the presence of the sliding around the switching surface is satisfied in the finite time. Simulation results as well as the experimental verifications prove the efficiency and applicability of the suggested approach in the presence of parametric uncertainty, noise, and exterior disturbance.Mechatronic Systems Desig
Fiction writing and History in the work of Laurent Gaudé.
No full textAuteur de l'extrême contemporain, Laurent Gaudé est à l'origine d'une œuvre littéraire riche et hétérogène qui plonge dans l'Histoire des hommes de l'Antiquité à nos jours : personnages historiques illustres (Alexandre le Grand, Frédéric II), conflits et catastrophes humaines (Grande Guerre, guerre d'Algérie, etc.), catastrophes naturelles (séismes, ouragan Katrina) composent ainsi une mosaïque d'(H/h)istoires qui affirment l'importance de l'être et chantent sa résistance à des univers de violence aliénants. Entre tragique et épique, l'œuvre de Laurent Gaudé est, de ce fait, une mise en récit de la crise humaine. Interrogeant l'Autre, l'Ailleurs et l'Autrefois, soulignant également la "fraternité de destins" des personnages gaudéens, le traitement fictionnel de l'Histoire s'inscrit dans une création littéraire humaniste qui redonne toute sa force à la fonction empathique de la littérature. Notre travail de recherche consiste à interroger cette odyssée temporelle, ce voyage à travers le temps et l’espace, pour comprendre les procédés de la mise en fiction de l’Histoire et sa dimension humaniste dans l’œuvre de Laurent Gaudé.Laurent Gaudé is an author from the Contemporary Extreme period. He creates a rich and diverse literary work which delves into the history of humanity from the Antiquity to these days. It summons famous historical figures like Alexander the Great, human conflicts and disasters (The Great War, Algerian War of Independence, etc.) and natural disasters (earthquakes in Italy and Haïti, hurricane Katrina). All these events draw a mosaic of (hi-)stories that affirms the importance of human beings and sings the resistance to alienating universes of violence. Therefore, the work of the novelist is a storytelling of human crisis which allies epic with tragic. By highlighting the "broterhood of destinies" of gaudeans characters, and questioning in the same time the Other, the Elsewhere and the Old times, fictional treatment of history by Laurent Gaudé is a part of a humanist literary creation which gives to the literature's empathetic function all its power. Our research involves questioning this temporal odyssey, this journey through time and space, to understand the processes of the fictionalization of history and its humanistic dimension in the work of Laurent Gaudé
