Search results for "Charge"
showing 10 items of 4686 documents
Comparaison ergonomique de deux systèmes de recherche d'information
2009
Etude expérimentale avec 56 participants. Comparaison des temps de recherche d'information et mesure de la charge cognitive dans le cadre d'une tâche de recherche d'information dans deux sites internet fictifs d'agence immobilière. L'un des sites est dit "classique" et l'autre dispose d'une possibilité de prévisualisation des pages web grace à un bouton dédié de la souris. Les résultats montrent que le système dit "transparent" est beaucoup plus efficace dans cette expérience y compris pour les publics les plus âgés.
Recherche d'information dans les documents numériques : vers une variation des modalités d'exécution procédurale
2011
National audience; L'objectif de la recherche présentée est de tester l'efficacité cognitive d'un nouveau système technique facilitant la recherche d'information dans les documents numériques. Ce système utilise un dispositif de prévisualisation par transparence permettant à l'utilisateur de consulter aisément des pages en profondeur. Une étude expérimentale a été conduite auprès de 36 participants, dont 26 étudiants et 10 personnes âgées. La tâche de recherche d'information consistait à trouver un appartement cible possédant un ou plusieurs critères spécifiques dans un site web d'agence immobilière spécialement conçu et contrôlé pour l'étude. Deux versions de ce site ont été testées. L'une…
Un système de navigation pour optimiser la recherche d’information sur le web
2014
National audience; Il est parfois difficile pour un utilisateur de trouver une information, de se déplacer ou se repérer sur le web. Au cours de sa recherche, celui-ci doit gérer une activité de navigation en sélectionnant des liens qui vont le conduire d’une page web à une autre ou d’un site web à un autre. Retrouver le parcours effectué dont on se souvient, est plus difficile du fait du caractère éphémère des pages. La recherche d’information sur un site web ou d’une page se fait selon une stratégie appelé « essai – erreur ». L’utilisateur ouvre une page web pour s’apercevoir que l’information recherchée ne correspond pas à son besoin. Il ferme ainsi la page puis décide d’en ouvrir une au…
Efficient Monolithic Perovskite/Perovskite Tandem Solar Cells
2016
Thin-film solar cells suffer from various types of recombination, of which leakage current usually dominates at lower voltages. Herein, we demonstrate first a three-order reduction of the shunt loss mechanism in planar methylammonium lead iodide perovskite solar cells by replacing the commonly used hole transport layer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with a better hole-selective polyarylamine. As a result, these cells exhibit superior operation under reduced light conditions, which we demonstrate for the extreme case of moonlight irradiance, at which open-circuit voltages of 530 mV can still be obtained. By the shunt removal we also observe the VOC to dro…
Analysis of the charge state distribution produced in a 78Kr + 98Mo fusion evaporation reaction utilizing the MARA separator
2016
Experimental results on the charge state distribution of the fusion evaporation reaction 78Kr + 98Mo are presented. The data has been taken from the 1st commissioning run of MARA (Mass Analysing Recoil Apparatus). Data from the charge states of q = 29 − 33 were collected. Here, q represents the elementary charge describing the number of electrons removed from a neutral atom. Results show an expected gaussian distribution around the most probable charge, ̄q. A most probable charge state of ̄q = (27.99 ± 0.20) was obtained after fitting the data. The value of ̄q was lower than initially anticipated, which was mainly a result of a less than desired beam energy delivered on the day of testing.
Azimuthal anisotropy of charged jet production in √sNN = 2.76 TeV Pb–Pb collisions
2016
We present measurements of the azimuthal dependence of charged jet production in central and semicentral √sNN = 2.76 TeV Pb–Pb collisions with respect to the second harmonic event plane, quantified as vch jet 2 . Jet finding is performed employing the anti-kT algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero vch jet 2 is observed in semi-central …
Charged jet cross sections and properties in proton-proton collisions at √s = 7 TeV
2015
The differential charged jet cross sections, jet fragmentation distributions, and jet shapes are measured in minimum bias proton-proton collisions at center-of-mass energy ffiffi s p ¼ 7 TeV using the ALICE detector at the LHC. Jets are reconstructed from charged particle momenta in the midrapidity region using the sequential recombination kT and anti-kT as well as the SISCone jet finding algorithms with several resolution parameters in the range R ¼ 0.2–0.6. Differential jet production cross sections measured with the three jet finders are in agreement in the transverse momentum (pT) interval 20 < pjet;ch T < 100 GeV=c. They are also consistent with prior measurements carried out at the LH…
Measurement of charged jet production cross sections and nuclear modification in p–Pb collisions at √sNN=5.02 TeV
2015
Charged jet production cross sections in p–Pb collisions at √sNN = 5.02 TeV measured with the ALICE detector at the LHC are presented. Using the anti-kT algorithm, jets have been reconstructed in the central rapidity region from charged particles with resolution parameters R = 0.2 and R = 0.4. The reconstructed jets have been corrected for detector effects and the underlying event background. To calculate the nuclear modification factor, RpPb, of charged jets in p–Pb collisions, a pp reference was constructed by scaling previously measured charged jet spectra at √s = 7 TeV. In the transverse momentum range 20 ≤ pT, ch jet ≤ 120 GeV/c, RpPb is found to be consistent with unity, indicating th…
Transverse energy production and charged-particle multiplicity at midrapidity in various systems from √sNN = 7.7 to 200 GeV
2016
Measurements of midrapidity charged-particle multiplicity distributions, dNch/dη, and midrapidity transverseenergy distributions, dET /dη, are presented for a variety of collision systems and energies. Included are distributions for Au + Au collisions at √sNN = 200, 130, 62.4, 39, 27, 19.6, 14.5, and 7.7 GeV, Cu + Cu collisions at √sNN = 200 and 62.4 GeV, Cu + Au collisions at √sNN = 200 GeV, U + U collisions at √sNN = 193 GeV, d + Au collisions at √sNN = 200 GeV, 3 He + Au collisions at √sNN = 200 GeV, and p + p collisions at √sNN = 200 GeV. Centrality-dependent distributions at midrapidity are presented in terms of the number of nucleon participants, Npart, and the number of constituent q…
Centrality dependence of particle production in p−Pb collisions at √sNN = 5.02 TeV
2015
We report measurements of the primary charged-particle pseudorapidity density and transverse momentum distributions in p-Pb collisions at √sNN = 5.02 TeV and investigate their correlation with experimental observables sensitive to the centrality of the collision. Centrality classes are defined by using different event-activity estimators, i.e., charged-particle multiplicities measured in three different pseudorapidity regions as well as the energy measured at beam rapidity (zero degree). The procedures to determine the centrality, quantified by the number of participants (Npart) or the number of nucleon-nucleon binary collisions (Ncoll) are described. We show that, in contrast to Pb-Pb coll…