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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

EXPERIMENTAL INVESTIGATIONS OF STEADY AND DYNAMIC BEHAVIOR OF TRANSVERSE LIQUID JETS

ELSHAMY, OMAR M. 02 July 2007 (has links)
No description available.
22

Tränas förmågorna i ämnet fysik? : En innehållsanalys av lärarnas planeringar, LPP:er samt hur lärarna övar förmågorna med eleverna i ämnet fysik.

Urthaler, Stephanie January 2017 (has links)
Abstract - Which abilities are the students training in the subject of physics? The purpose of this study was to examine teachers' plans, LPPs (Local Educational Planning) to see which abilities are trained and how. I have created a content analysis of the teachers' plans, LPPs and how the teachers practice the abilities of the students in the subject of physics. I analysed two LPPs in the grade 5 and two LPPs in the grade 6. The LPPs are from two different schools and two teachers' one in each grade. My first purpose was to examine which abilities, prescribed in Lgr 11 students are training and if the abilities create a common thread between grade 5 and grade 6 in the subject of physics. My second purpose was to examine what kind of teaching the students are training the abilities which can be found in Lgr 11. The study addresses three different kinds of teaching which are more open, more guided or in a combined way of teaching. My study answered the following questions: Which abilities in Lgr 11 are the students training in the subject of physics in grade 5 and 6? What kind of teaching are the students training the abilities in Lgr 11? The study was based on a content analysis of the LPPs and the theory I used to analyse was The Big 5. I also used interview by email with the teachers who gave me the LPPs. Based on the results and the analysis of the study, I came to the conclusion that all four LPPs in the two different schools were practicing the abilities prescribed in Lgr 11 and that they used The Big 5 to clarify the abilities that the topic addresses. All four LPPs have a common thread between grade 5 and 6 where some abilities are recorded again others are excluded and supplemented with new ones. Based on the results and the analysis, I came to the conclusion that both teachers teach the skills prescribed in Lgr 11 in the subject of physics in an open way of teaching, i.e. when students are active participants in the teaching. Combined teaching was used several times when the students e.g. had to try out for a given topic. Guided teaching was used only once in all four LPPs e.g. when the teachers prepare a list of concepts.
23

Contrôle des propriétés magnéto-optiques de systèmes magnétoplasmoniques grâce à la nanostructuration / Tailoring magneto-optical properties of magnetoplasmonic systems through nanostructuration

Ding, Xiaokun 24 January 2017 (has links)
Ce travail de thèse porte sur le contrôle des propriétés de trois systèmes magnéto-plasmoniques grâce à différents types de nanostructuration. Ces structures sont basées respectivement sur la Propagation de Plasmons de Surface (SPP), les Plasmons de Surface Localisés (LSP) et la spectroscopie d’interférences en réflexion (RIfS). La manipulation des propriétés magnéto-optiques (MO) pour une utilisation dans les biocapteurs est discutée. Le premier système est une structure SPP en couche mince de couches de métaux nobles et d’un matériau magnétique de type multicouche présentant une anisotropie uni-axiale contrôlée. L’anisotropie de la couche magnétique se reflète sur les propriétés plasmoniques. Une amélioration de l’activité magnéto-optique peut être mise à profit pour améliorer la sensibilité de capteurs basés sur cette structure. Le second dispositif est une structure LSP avec nanoparticules d’or et d’une couche magnétique continue. Il est démontré qu’une couche diélectrique entre la couche magnétique et les nanoparticules d’or est indispensable pour préserver la résonance plasmonique. L’épaisseur de la couche magnétique a un effet sur cette dernière qui peut en principe être mise à profit pour influer sur l’activité magnéto-optique. La troisième approche est une structure RIfS composée d’un système multicouche magnéto-plasmonique Ag/ITO/CoFeB/ITO/Ag déposé sur un substrat nanoporeux d’oxyde d’aluminium anodique (AAO). Le signal RIfS dépend de la taille et de la longueur des nanopores. Le diamètre des nanopores affecte également la réponse magnéto-optique en réflexion en générant une inversion du signe des cycles d’aimantation mesurés par effet Kerr. / This PhD dissertation deals with the tuning of the magneto-optical (MO) response of three different magnetoplasmonic systems by using different nanostructuration schemes. They are structures based on SPPs, LSPs and RIfS, respectively. The manipulation of MO activity to be used in biosensors and to improve the sensitivity is also discussed. The first system is thin-film SPP structure consisting of magnetic and plasmonic layers, where the magnetic part is nanostructured multilayers with controlled uni-axial anisotropy. The uni-axial anisotropic properties of the multilayered magnetic materials were clearly reflected on the plasmonic properties of the system. An enhancement in the MO activity can be used to improve the sensitivity of the sensors based on this structure. The second system is a LSP-based magnetoplasmonic structure consisting of Au nanoparticle arrays and continuous magnetic layers. It is demonstrated that a dielectric layer in between Au nanoparticles and ferromagnetic layers is indispensable in order to preserve the plasmonic resonance. The thickness of magnetic layers has an effect on the plasmonic property, which can be further used to tune the MO activity. The third system is a hybrid RIfS structure with a magnetoplasmonic multilayer Ag/ITO/CoFeB/ITO/Ag deposited on a nanoporous AAO substrate. The RIfS signal depends on both the size and the length of the nanopores. The diameter of the nanopores also affects the MO response by generating a reversal in the sign of the Kerr loops. This can be viewed as the tuning factor of MO activity of the structure.
24

Relevance of the Irrelevant : Using Task-Irrelevant Emotional Stimuli to Test the Load-Hypothesis through ERP’s

Andersson, Per January 2010 (has links)
<p>The role of attention and perceptual resources were studied in a one-back task and a letter-search task, both using the same stimuli. In the letter task, pictures were used as task-irrelevant and distracting emotional stimuli. The emotional processing of the pictures was measured through the Late Positive Potential (LPP), an event-related potential (ERP) recorded with EEG. LPP activity was significantly greater to emotional than neutral stimuli during the one-back task; this shows that emotional stimuli were processed during an easy task (low load). However, LPP activity dropped for all stimuli during the difficult perceptual task (high load). Selective processes of attention are discussed, in relation to Load Theory and the ability to ignore task-irrelevant, but emotionally significant, stimuli.</p>
25

Relevance of the Irrelevant : Using Task-Irrelevant Emotional Stimuli to Test the Load-Hypothesis through ERP’s

Andersson, Per January 2010 (has links)
The role of attention and perceptual resources were studied in a one-back task and a letter-search task, both using the same stimuli. In the letter task, pictures were used as task-irrelevant and distracting emotional stimuli. The emotional processing of the pictures was measured through the Late Positive Potential (LPP), an event-related potential (ERP) recorded with EEG. LPP activity was significantly greater to emotional than neutral stimuli during the one-back task; this shows that emotional stimuli were processed during an easy task (low load). However, LPP activity dropped for all stimuli during the difficult perceptual task (high load). Selective processes of attention are discussed, in relation to Load Theory and the ability to ignore task-irrelevant, but emotionally significant, stimuli.
26

Traitement de stimuli sexuels visuels statiques par l’insula en EEG intracrânien : une étude de potentiels évoqués

Brideau-Duquette, Mathieu 08 1900 (has links)
No description available.
27

Facial expressions and Electrophysiological impressions : An LPP study of emotional regulation

Ekvall, Viveka January 2019 (has links)
The conceptual model of emotion regulation (ER) of Gross and Thompson (2007) introduces families of ER strategies ordered on a temporal scale. This scale has been attributed implications both for the grouping strategies but also for the neurocognitive processing. The two event-related potential (ERP) studies of emotional regulation presented here focus on emotional regulation at different temporal distances, as well as, different stages of cognitive processing. Trying to discern if various neural processes could be disentangled by looking at different stages of the late positive potential (LPP). The theoretical background begins with the neurocognitive science of emotionality and visits cognitive processing at both early and late stages before summating results of the contemporary research of emotional regulation. 39 participants were enrolled within the two experiments aiming to compare the efficiency of different strategies in reducing negative social emotion induced by photographs of angry faces. Technical difficulties discourage conclusions about how temporal distancing is most effectively adapted. Results suggest self-focused distancing strategies are more effective than situation-focused reappraisal and could be preferred for therapeutic purposes based on greater observed LPP effect.
28

Neurální koreláty multimodálního afektivního primingu / Neural correlates of cross-modal affective priming

MRHÁLEK, Tomáš January 2019 (has links)
This dissertation aims to investigate the correlations of visual evoked potentials during the experimental process of serial passive affective priming. The aim of this dissertation is to identify partial processes of affective perception, which are influenced by relations to previous affective priming stimulation. The research is designed as a laboratory EEG experiment, which uses affective priming techniques, particularly its sequential passive multimodal (auditory-visual) variation. The research experimentally manipulates emotional characteristics of stimuli that are constructed on the basis of the dimensional theory. As a starting dimension, arousal was chosen that is equivalent to psychic activation connected to reactions to stimuli. The study was carried out in the PF JČU neurological laboratory using a 64 channel EEG Biosemi Active II. Probands was selected from the JČU students, whose brain electrical activity was measured during an exposure to affective stimuli from international emotional elicitation databases. Records from 29 people were used. The independent variable used was the variation of priming and arousal characteristics of the priming stimulus from the affective melodies database (Eerola &Vuoskoski, 2010) and the arousal characteristics of a visual stimuli (Marchewka et al., 2014). Visual perception is the most explored ERP process, therefore the differences between the results of this dissertation study and comparative studies can be the basis for interpreting the mechanism of contextual affective transmission. Time progress and activation reactions are modulated based on experimental conditions and the dependent variables are the differences of latency and amplitude of individual components of evoked potentials, which represent partial psychological processes. The use of sound as priming stimulus together with a high interstimulus interval decreases the conflict between perceptual processes in selective attention. The differences in processes of visual perception according to affective arousal characteristics of stimuli suggest a parietally increased early posterior negativity (EPN) and late positive potentials (LPP) of high-arousal stimuli in comparison to low-arousal stimuli. Signs of EPN manifest as indicators for prioritization of attention in comparison with actively motivating stimuli. The priming effect manifested in P1 and N1 components occipitoparietally and in N2 centroparietally, which suggest stronger negativity of EPN in the case of previous priming. LPP increase for the priming condition was there only for high-arousal stimuli. The cause for higher activation for priming conditions in P1 and N1 is unknown, it is a case of premature latency for possible explanation using the evaluation mechanism. The results showcase the influence of conflict between processes of attention or the alternative interpretations of affective priming based on the influence of context on the formation of evaluative conclusions. The priming effects in LPP show a lower later parietal activation of primed stimuli which can be connected to their previous increased activation as a part of early and medium latency component.
29

Youth Emotion Regulation and Processing: Risk and Resilience Factors in the Context of Maternal Depression

Patton, Emily 13 September 2016 (has links)
No description available.
30

Application de la LIF de molécules aromatiques au dosage de carburants fossiles et biocarburants / Application of the aromatic-based laser-induced fluorescence diagnostic to the quantitative chemical probe of Fossil fuels and Biofuels

Ledier, Constantin 13 December 2011 (has links)
Les industries automobile et aéronautique sont confrontées dans le futur proche à une raréfaction des carburants fossiles, ainsi qu’au problème de pollution de l’environnement émis par les systèmes propulsifs. Pour s’affranchir de ces problèmes, l’utilisation de carburants alternatifs censés apporter rendement et préservation de l’environnement, s’est considérablement développée ces derniers temps. Cependant, leurs impacts sur la pollution, consommation et rendement de combustion ne sont toujours pas clairement établis. En particulier, il est nécessaire de quantifier leurs effets sur les phénomènes physiques clés à la base des processus que sont l’évaporation du carburant liquide et le mélange carburant vapeur/air. L’analyse expérimentale de ces processus physiques nécessite alors l’emploi de diagnostics lasers non-intrusifs et quantitatifs, permettant de mesurer des grandeurs physiques comme les distributions spatiales instantanées de température et de concentration du carburant en phase vapeur. Parmi les techniques optiques les plus attrayantes, l’imagerie de fluorescence induite par laser (PLIF) offre de nombreux avantages. L’objectif de la thèse a été, dans un premier temps, de caractériser les propriétés spectroscopiques de quatre carburants multi-composants, le kérosène (Jet A1), le Biomass-to-Liquid (BtL), le Diesel et l’Ester Méthylique Huile Végétale (EMHV) qui, mis à part le premier, possèdent des propriétés spectroscopiques encore peu connues. L’exploitation de leurs propriétés de fluorescence a ensuite permis d’évaluer leurs capacités à fournir des signaux autorisant la mesure de la température et de la concentration du carburant en phase vapeur. Dans un second temps, un étude exhaustive des propriétés de fluorescence de plusieurs cétones (3-pentanone, benzophénone) et aromatiques (fluoranthène, acénaphtène, naphtalène, 1,2,4-triméthylbenzène…) en fonction de la température et du quenching de l’oxygène moléculaire, a été réalisée à pression atmosphérique pour identifier les traceurs fluorescents potentiellement adaptés au dosage optique des quatre carburants. Les données photophysiques collectées ont ensuite été utilisées pour parfaire l’établissement des couples carburants/traceurs fluorescents ainsi que les stratégies de mesures de température et de concentration de carburant associées. L’exploitation des données acquises lors de différentes campagnes de mesures a ainsi mis en évidence la possibilité de détecter simultanément la fluorescence de plusieurs molécules aromatiques (mono-, di- et/ou tri-aromatique) naturellement présentes ou ajoutées artificiellement dans les carburants. Le cas du Diesel a nécessité le développement d’un carburant modèle pour permettre une étude de son évaporation. L’application de cette nouvelle approche PLIF a été validée sur un injecteur hélicoptère LPP de nouvelle génération fonctionnant avec trois carburants spécifiques que sont le Jet A1, le BtL et un mélange Jet A1/BtL / The automotive and aviation industries are presently confronted with the twin crises of fossil fuel depletion and environmental degradation. Research for alternative fuels, which promise a harmonious correlation with sustainable development, energy conservation, efficiency and environmental preservation, has become highly pronounced in the present context. However, their influence on pollution, consumption and combustion yield are not clearly defined yet. In particular, their effects on key physical processes that initiate these phenomena like fuel evaporation and mixing processes between fuel vapour and air have to be quantified. Experimental analysis of these processes requires the use of non-intrusive and quantitative laser diagnostics, allowing the measurement of key physical parameters like instantaneous spatial distribution of temperature and fuel vapour concentration. Among the optical techniques available thus far, planar laser-induced fluorescence (PLIF) offers many advantages for the study such processes in combustors. The objective of this thesis is then to propose and to develop innovative PLIF strategies to measure fuel distribution and mixture formation when fossil fuels and biofuels are used in aeronautical and automotive combustion chambers. In particular, the fluorescence of various fossil fuels like kerosene (Jet A1) and Diesel, the biodiesel fuel containing Esters (FAME) and the Biomass-To-Liquid fuel (BtL) are investigated. The exploitation of their fluorescence was then used to analyse their capacity to generate signals providing from fluorescent tracers (either present naturally in the fuel or chemically added) that could be used as probe molecules for the measurement of temperature and fuel vapour concentration. To select theses tracers, an exhaustive study of the fluorescence properties of various ketones (3-pentanone, benzophenone) and aromatic molecules (fluoranthene, acenapthene, naphthalene, 1,2,4-trimethylbenzene) with temperature and quenching with molecular oxygen was performed at atmospheric pressure. The photophysical data collected during these experiments have been then used to associate the various fuels with specific fluorescent tracers and to elaborate the strategies of measurement of temperature and fuel concentration associated. Exploitation of the data collected during this thesis thus highlighted the possibility to detect simultaneously the fluorescence of various aromatic molecules (mono-, di-, tri-aromatics) naturally present or artificially seeded in fuels. The specific case of Diesel required the development of a surrogate fuel which allows the study of its evaporation process. An application of these innovative strategies of PLIF measurements has been finally performed on a new generation LPP helicopter injection system running at atmospheric pressure with the following fuels: Jet A1, BtL and a mixture of Jet A1 and BtL. Results obtained allowed the validation of the PLIF strategies defined in this thesis.

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