Yes / In this paper, we present an analytical study for the investigation of the effects of the magnetoelectric elements of a reciprocal and nonreciprocal bianisotropic grounded substrate on the input impedance, resonant length of a dipole antenna as well as on the mutual coupling between two element printed dipole array in three configuration geometries: broadside, collinear and echelon printed on the same material. This study examines also the effect of the considered bianisotropic medium on the electric and magnetic field distributions that has been less addressed in the literature for antenna structures. Computations are based on the numerical resolution, using the spectral method of moments, of the integral equation developed through the mathematical derivation of the appropriate spectral Green’s functions of the studied dipole configuration. Original results, for chiral, achiral, Tellegen and general bi-anisotropic media, are obtained and discussed with the electric and magnetic field distributions for a better understanding and interpretation. These interesting results can serve as a stepping stone for further works to attract more attention to the reciprocal and non-reciprocal Tellgen media in-depth studies.

Le travail théorique présenté dans cette thèse concerne la formation de molécules ultra-froides bialcalines et le contrôle de leurs degrés de liberté externes et internes. Cette étude est motivée par les nombreuses expériences en cours visant à l'obtention d'un gaz quantique dégénéré de molécules dans leur état fondamental absolu. Le schéma de formation étudié repose sur le processus de transfert adiabatique stimulé (STIRAP) réalisé en présence d'un potentiel optique de piégeage (réseau optique) des atomes et des molécules.Nous avons déterminé les paramètres du réseau optique (intensité et fréquence du champ laser) qui permettent de piéger efficacement des dimères d'alcalins en évaluant la polarisabilité dynamique acquise par les molécules soumises à un champ externe. Ces calculs reposent en particulier sur la connaissance détaillée de la structure électronique des molécules. Nous avons identifié des plages de longueur d'ondes dites « magiques » où la polarisabilité est la même pour chaque niveau peuplé au cours du transfert adiabatique, permettant ainsi un transfert optimal. Ce formalisme nous a également permis d'obtenir les coefficients Van der Waals de l'interaction à longue portée nécessaires pour étudier les taux de collisions entre molécules.Nous avons réalisé une étude plus détaillée de la molécule RbCs. En étudiant précisément la probabilité de transition de la molécule vers un niveau excité, nous avons proposé un schéma STIRAP pour transférer des molécules de RbCs, initialement dans un niveau vibrationnel excité, vers leur état rovibrationnel fondamental.Ces travaux ont montré l'importance de la connaissance précise de la structure hyperfine de l'état électronique moléculaire excité pour réaliser un gaz dégénéré de molécules dans un état quantique bien défini. Un modèle asymptotique nous a permis d'obtenir une première estimation de la structure hyperfine des courbes d'énergies potentielles des premiers états moléculaires excités des molécules Cs2 et RbCs. / The theoretical work presented in this thesis is focused on the formation of ultracold bialcaline molecules and on the control of their external and internal degrees of freedom. This study is motivated by the increasing number of experiments aiming at obtaining a quantum degenerate gas of molecules in their absolute ground state. The formation scheme we worked on is based on the Stimulated Raman Adiabatic Passage (STIRAP) technique operated while molecules are trapped inside an optical lattice.We have determined the parameters of the optical lattice (intensity and wavelength of the laser) that allow for an efficient trapping of the alkali dimers by evaluating the dynamic polarizability of molecules in the presence of an external field. Such calculations require the accurate knowledge of the electronic structure of the molecules. We have identified the so-called ``magic'' wavelength for which all levels populated during the STIRAP sequence have the same polarizability, thus ensuring an optimal transfer. The same approach has also been used to compute the strength of the long-range interaction between polar bialkali molecules needed to evaluate collision rates.The particular case of the RbCs molecule has been investigated. We have selected a radiative transition allowing for an efficient STIRAP scheme yielding molecules in their rovibrational ground state. These works have raised the need for the precise knowledge of the hyperfine structure of the excited electronic molecular state involved in the STIRAP scheme. We have developed an asymptotic model to obtain a first estimate of the hyperfine structure for the potential curves of the lowest excited states of Cs2 and RbCs.

This thesis is devoted to optical properties of Aharonov-Bohm quantum rings in external electromagnetic fields. It contains two problems. The first problem deals with a single-electron Aharonov-Bohm quantum ring pierced by a magnetic flux and subjected to an in-plane (lateral) electric field. We predict magneto-oscillations of the ring electric dipole moment. These oscillations are accompanied by periodic changes in the selection rules for inter-level optical transitions in the ring allowing control of polarization properties of the associated terahertz radiation. The second problem treats a single-mode microcavity with an embedded Aharonov-Bohm quantum ring, which is pierced by a magnetic flux and subjected to a lateral electric field. We show that external electric and magnetic fields provide additional means of control of the emission spectrum of the system. In particular, when the magnetic flux through the quantum ring is equal to a half-integer number of the magnetic flux quantum, a small change in the lateral electric field allows tuning of the energy levels of the quantum ring into resonance with the microcavity mode, providing an efficient way to control the quantum ring-microcavity coupling strength. Emission spectra of the system are calculated for several combinations of the applied magnetic and electric fields.

This thesis presents solutions and studies related to the design of wideband antennas for wireless handheld terminal applications. A method of electrically shortening the terminal chassis length to obtain resonance at high frequencies has been proposed and evaluated, thereby increasing the antennas impedance bandwidth. No significant effect on the lower frequency band in a dual-band antenna prototype has been observed, making the method suitable for multi-band applications. The chassis has further been utilized as a zero-thickness 0.9 - 2.7 GHz high efficiency antenna by inserting a notch in the chassis center, and a feasibility study for typical phones has been performed. Additionally, the effect of talk position on the chassis wave-mode has been investigated, where the standard equivalent circuit model for terminal antennas has been modified to include the presence of the users head. The model has been used to explain measured and simulated effects concerning frequency detuning, efficiency reduction and bandwidth enhancements when the terminal is placed in talk position. The use of a hands-free earpiece cord is currently mandatory for FM radio reception as the cord is utilized as antenna. However, there is currently a market driven demand for removing the cord requirement since many modern phones are equipped with speakers and Bluetooth headsets. In this thesis, an active ferrite loop antenna is proposed as an internal replacement/complement with a performance of -23 dB (G/T degradation) compared to a full-size lossless dipole in urban environments. Also, a modification to the cord is suggested for DVB H reception. Complex matching networks have been investigated to increase the bandwidth of dual band PIFA antennas, and a printed dual band dipole has been integrated with a modified Marchand balun for dual resonance at two separate frequency bands, thus covering the commercial cellular bands 824-960 and 1710-2170 MHz with a single antenna.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This paper presents the implementation of an artificial magnetic ground-plane with a low profile Log-periodic Dipole Array (LPDA) antennas. After the properties of three typical Electromagnetic Bandgap (EBG) structures are investigated and their bandwidth properties are studied, a mechanism is presented to improve the band-width over which the EBG surface acts as a perfect magnetic conductor (PMC). A low profile LPDA is modeled above this surface and the results indicate an improved band-width region. Compared with a LPDA in free space the frequency band is shifted higher by the EBG surface and the gain pattern is shifted from a horizontal orientation to a vertical orientation. / AFRIKAANSE OPSOMMING: Hierdie dokument stel voor die implementering van kunsmatige magnetiese grondvlakke met Logaritmiese Periodiese Dipool Samestelling (LPDS) antennas. Die eienskappe van drie tipiese Elektromagnetiese Bandgaping (EBG) strukture word ondersoek en hul bandwydte eienskappe word bestudeer. ’n Meganisme word voorgestel om die bandwydte te verbeter waar die EBG oppervlakte soos n perfekte magnetiese geleier optree. ’n Lae profiel LPDS word bo hierdie oppervlakte geplaas. Die resultate dui aan ’n verbetering in the bandwydte. In vergelyking met ’n LPDS in vrye ruimte skuif die frekwensie band ho¨er as gevolg van die EBG oppervlakte en die aanwins patroon skuif van ’n horisontale orientasie na ’n vertikale orientasie.

Les oscillations jouent un rôle de premier plan dans la mise en place des réseaux cérébraux sains et pathologiques. En particulier, au niveau clinique, les activités oscillatoires sont d'une grande importance diagnostique en épilepsie. Par ailleurs, les méthodes non-invasives d'électrophysiologie sont particulièrement adaptées pour la compréhension des réseaux cérébraux à grande échelle. Cependant, la majorité des études en épilepsie a été dirigée vers les pointes intercritiques, qui sont des activités transitoires. Une question qui reste donc en suspens est le lien entre les pointes épileptiques et les activités oscillatoires épileptiques. Cette thèse a visé à résoudre deux problématiques complémentaires autour de cette question. La première problématique est la séparation adéquate entre les activités oscillatoires et transitoires. Il s'agit d'une tâche difficile surtout lors d'un grand chevauchement temporel, qui peut résulter en la contamination d'une activité par l'autre. Nous avons évaluée trois méthodes de filtrage : le filtre FIR (méthode classique), la transformé d'ondelette stationnaire et le filtrage parcimonieux par matching pursuit (MP, basé sur un dictionnaire). Sur des simulations, la SWT a donné de très bons résultats pour la reconstruction des transitoires et le MP pour les oscillations ; de plus, les deux méthodes ont donné un faible taux de faux positifs en détection automatique des oscillations. La SWT et le FIR ont donné les meilleurs résultats de filtrage sur les signaux réels, en particulier lors de la localisation de source. / The Oscillatory activities play a leading role in the development of healthy and pathological brain networks. In particular, at the clinical level, the oscillatory activities are of great importance in the diagnostic of epilepsy. In addition, the non-invasive electrophysiology methods are particularly suitable for understanding the large-scale brain networks. However, most studies in epilepsy have been directed to the interictal spikes, which are transitional activities. One issue that remains unresolved is the relationship between epileptic spikes and epileptic oscillatory activities. This thesis resolves two complementary problems. The first one is the suitable separation between the oscillatory and transitory activity, which is quite sensitive to the presence of the overlap in the time-frequency domain. This can lead to a contamination between the activities. We did evaluate three filtering methods: the FIR (classic methods), the stationary wavelet SWT and the parsimonious filter with the matching pursuit MP. The SWT gave good results in the reconstruction of transient activity and the MP in the reconstruction of oscillatory activity both for simulated data; also they provide a low false positive in automatic detection of oscillatory activity. The SWT and FIR gave the best results on real signals especially for source localization. In the simulated data, the MP is optimal since the atoms of the dictionary resembles to the simulated signals, which isn't guaranteed for real signals. The second problem is the comparison between network connectivity of transient and oscillatory activity, as measured in surface recordings (MEG) and invasive recordings SEEG.

Le sujet de cette thèse sont les amplitudes d'hélicités de la leptoproduction exclusive et diffractive du méson rho dans la limite de Regge perturbative et au-delà du twist dominant. La compréhension de pareils processus exclusifs en termes des constituants élémentaires de QCD est un important défi pour comprendre la structure des hadrons. On présente ici deux nouveaux modèles phénoménologiques basés sur la kT-factorisation des amplitudes d'hélicités en un facteur d'impact γ*(λ) → ρ(λ'), où λ et λ' dénotent les polarisations du photon virtuel et du méson rho, et le facteur d'impact du nucléon cible. Les facteurs d'impacts γ*(λ) → ρ(λ') sont calculés en utilisant la factorisation colinéaire pour séparer la partie molle du méson rho. Le premier modèle est obtenu en combinant les résultats respectivement de twist 2 et twist 3 des facteurs d'impacts où les deux polarisations sont longitudinales ou transverses, avec un modèle pour le facteur d'impact du nucléon et un modèle pour les distributions d'amplitudes du méson rho. Dans la seconde approche présentée dans cette thèse, on calcule ces facteurs d'impacts dans l'espace des paramètres d'impacts et on montre que l'amplitude de diffusion d'un dipôle de couleur avec le nucléon se factorise, permettant de combiner nos résultats avec un modèle de section efficace de dipôle. On obtient en très bon accord avec les données de H1 et ZEUS pour des virtualités plus grandes que quelques GeV. Nous discutons les résultats obtenus et les comparons à d'autres modèles existants. / This thesis deals with the computation of the helicity amplitudes of the exclusive diffractive rho meson leptoproduction in the perturbative Regge limit beyond the leading twist. The understanding of such exclusive processes in terms of the elementary constituents of QCD is a serious challenge to understand the hadronic structure. We present two new phenomenological models based on the kT-factorization of the helicity amplitudes in a γ*(λ) → ρ(λ') impact factor, where λ and λ' denote the polarizations of the virtual photon and the rho meson, and the nucleon target impact factor. The γ*(λ) → ρ(λ') impact factors are then computed using the collinear factorization of the rho meson soft part. The first model relies on the combination of the results respectively up to twist 2 and twist 3 for the impact factors where both polarizations are longitudinal or transverse, with a model for the nucleon impact factor and a model for the distribution amplitudes of the rho meson. In the second approach presented in this thesis, we derive these impact factors in impact parameter space and show that the color dipole scattering amplitude with the nucleon factorizes, allowing to use our results in combination with dipole cross-section models. We get a very good agreement with the data from H1 and ZEUS collaborations for virtualities higher than a few GeV. We discuss our results and compare them to other models.

Este trabalho teve como foco principal a caracterização espectroscópica dos haletos de berílio, BeCl, BeBr e BeI. O conhecimento acerca dessas espécies foi ampliado significativamente através do cálculo de parâmetros de difícil caracterização experimental. Como os poucos trabalhos experimentais realizados para esses haletos apresentam resultados inconclusivos para a transição C 2Σ+ - X 2Σ+, através do cálculo acurado de probabilidades de transição foi possível oferecer uma nova interpretação para os dados existentes, apresentando inclusive resultados para as outras transições eletrônicas até o presente desconhecidas. Cálculos utilizando o método de Interação de Configurações Multirreferencial (MRCI) com um conjunto de funções de base consistentes na correlação de qualidade quintupla-zeta foram utilizados para se obter as curvas de energia potencial associadas ao primeiro e segundo canais de dissociação para os estados dubleto e quarteto dessas espécies. Parâmetros espectroscópicos como as constantes vibracionais we, wexe, a constante rotacional Be e a distância de equilíbrio foram determinados para os estados de mais baixa energia. Além disso, foram calculadas a energia de excitação (Te) e a energia de dissociação (De) com e sem a inclusão de efeitos spin-órbita. Os resultados obtidos expandiram significativamente nosso conhecimento sobre os estados eletrônicos dessa espécies. Para os estados já investigados experimentalmente, houve boa coerência entre os parâmetros calculados e experimentais. As diferenças de energia entre os dois canais no limite de dissociação para as moléculas BeCl, BeBr e BeI obtidas neste trabalho foram, respectivamente: 21835, 21889 e 21998 cm-1, em concordância com o respectivo resultado experimental das três espécies (21980 cm-1). A determinação teórica da energia de dissociação D0 foi bastante satisfatória. Obtivemos 92,24; 72,77 e 51,75 kcal·mol-1, respectivamente, para as moléculas BeCl, BeBr e BeI incluindo os efeitos spin-órbita, comparados a 91,78, 71 e 57 kcal·mol-1. Para uma análise mais completa das curvas de energia potencial, elas também foram obtidas considerando-se os efeitos relativísticos. A constante de acoplamento spin-órbita calculada na região de equilíbrio de cada uma das moléculas BeCl, BeBr e BeI foi, respectivamente: 41, 207 e 324 cm-1, em boa concordância com os resultados experimentais: 52,8, 198 e 361,1 cm-1, respectivamente. A separação spin-órbita no limite de dissociação calculada foi de 823, 3446 e 6975 cm-1 (BeCl, BeBr e BeI), também coerentes com resultados experimentais: 882, 3685,24 e 7603,15 cm-1, respectivamente. Foi ainda realizada uma análise detalhada sobre os canais de dissociação das moléculas HBeP e BePH. A construção de um diagrama de energias relativas permitiu obter um conjunto de dados importantes a respeito de todos os possíveis canais de dissociação. Em particular é mostrado a estabilidade relativa e a energia no limite de dissociação. Para a energia no limite de dissociação obtivemos resultados consistentes com os valores experimentais. Nossos cálculos para os três primeiros canais de dissociação HBeP = H + Be resultaram nos seguintes valores: H (2Sg) + Be (X 4Σ+), 0 cm-1; H (2Sg) + Be (a 2π), 426 cm-1 (exp. 502 cm-1); H (2Sg) + Be (b 2Σ-), 1896 cm-1 (exp. 1976 cm-1). Por fim, pela primeira vez na literatura, o calor de formação e de atomização foram calculados para estas espécies. Para os isômeros HBeP e BePH, a energia de atomização a 298,15 K calculada foi de 119,02 kcal·mol-1 e 107,40 kcal·mol-1, respectivamente; para o calor de formação a 298,15 K, obtivemos 86,14 e 97,76 kcal·mol-1 para as espécies HBeP e BePH, respectivamente. / This work has mainly focused on the spectroscopic characterization of the beryllium halides, BeCl, BeBr and BeI. Knowledge about these species was substantially increased through the calculation of parameters that are difficult to access in an experimental characterization. As the few experimental works carried out for these halides presented inconclusive results for the C 2Σ+ - X2Σ+ transition, we carried out accurate calculations of transition probabilities, thus offering a new interpretation about the existing data, including also results for other electronic transitions as yet unknown. Calculations using the method Multireference Configuration Interaction (MRCI) along with correlation-consistent basis set functions of quintuple-zeta quality were used to obtain the potential energy curves associated with the first and second dissociation channels for the doublet and quartet states of these species. Spectroscopic parameters such as vibrational constants We, WeXe, the rotational constant Be and the equilibrium distance were determined for the low-lying states. Furthermore, we also calculated the excitation energy (Te) and the dissociation energy (De) with and without the inclusion of spin-orbit effects. The obtained results significantly expanded our knowledge about the electronic states of this species. For states already investigated experimentally, there was good consistency between the calculated and the experimental parameters. The energy differences between the two channels in the dissociation limit for BeCI, BeBr and Bel molecules obtained in this work were: 21835, 21889 and 21998 cm-1, in agreement with the corresponding experimental results of the three species (21 980 cm-1). The theoretical determination of the dissociation energy D0 was very satisfactory. We obtained 92.24, 72.77, and 51.75 kcal·mol-1, respectively, for the BeCl, BeBr and BeI molecules including spin-orbit effects, compared to 91.78, 71 and 57 kcal . mol-1. For a more complete analysis of the potential energy curves, they also were obtained considering relativistic effects. The calculated spin-orbit coupling constants in the equilibrium region of BeCl, BeBr and BeI molecules were respectively 41, 207 and 324 cm-1, in good agreement with the experimental results: 52.8, 198, and 361.1 cm-1, respectively. The calculated spin-orbit splitting in the dissociation limit was 823, 3446 and 6975 cm-1 (BeCl, BeBr and BeI) also consistent with the experimental results: 882, 3685.24 and 7603.15 cm-1, respectively. Additionally, a detailed analysis of the dissociation channels of HBeP and BePH molecules was performed. The construction of a relative energies diagram allowed us to derive a set of important data for all the possible dissociation channels. In particular, it is shown the relative stability and the energy in the dissociation limit. For the energy in the dissociation limit, we obtained results consistent with the experimental values. Our calculations for the first three dissociation channels HBeP = H + Be resulted in the following values: H (2Sg) + Be (X 4Σ+), 0 cm-1; H (2Sg) + Be (a 2π), 426 cm-1 (exp. 502 cm-1); H (2Sg) + Be (b 2Σ-), 1896 cm-1 (exp. 1976 cm-1). Finally, for the first time in the literature, the heat of formation and the atomization energy were calculated for these species. For the HBeP and BePH isomers, the atomization energy calculated at 298.15 K was 119.02 and 107.40 kcal . mol-1, respectively; for the heat of formation at 298.15 K, we obtained 86.14 and 97.76 kcal· mol-1 for HBeP and BePH species, respectively.

Neste trabalho estudamos algumas interações entre átomos de Rydberg em uma armadilha ótica de dipolo do tipo QUEST. Com esta armadilha obtemos uma amostra de 1,2 × 106 átomos de 85Rb no estado fundamental, à uma densidade de ∼ 1012 átomos/cm3 e temperatura média de 60 µK. Os átomos de Rydberg foram preparados utilizando uma transição de dois fótons a partir do estado fundamental 5S1/2, passando pelo estado intermediário 5P3/2 e em seguida para o estado de Rydberg desejado. Estudamos a interação entre pares de átomos, em diferentes níveis energéticos, através de duas técnicas diferentes. Na primeira, monitoramos os efeitos de transferência de população em estados nD oriundas de uma ressonância Förster. Estudamos a ressonância nD5/2 + nD5/2 → (n+2)P3/2 + (n2)F7/2 onde 37 ≤ n ≤ 47, em função da densidade da amostra atômica; e para o estado 37D5/2 manipulamos a mesma ressonância com a aplicação de um campo elétrico externo. Os resultados mostraram que este é um processo binário, evidenciado pela dependência quadrática da população no estado produto com relação ao estado excitado. Num outro experimento, estudamos a interação entre estados nS através do monitoramento, e controle, do efeito de bloqueio de excitação. Aqui mostramos que é possível controlar as interações interatômicas em uma amostra quasi-unidimensional de átomos de Rydberg variando a orientação de um campo elétrico externo. Mostramos que ao polarizar uma amostra de átomos no estado 50S1/2 com um campo, esta passa a interagir de modo semelhante ao de dipolos elétricos clássicos, onde a interação pode ser controlada com a variação da orientação dos dipolos atômicos. Tal interação pode, inclusive, ser cancelada quando os dipolos elétricos são alinhados em um ângulo de 54,7° com relação ao eixo internuclear. / In this work we have studied some interactions between Rydberg-atoms in a QUEST type optical dipole trap. With this trap we obtained a sample of 1,2 × 106 85Rb atoms in the ground state, in a density of ∼ 1012 atoms/cm3 and average temperature of 60 µK. The Rydberg-atoms were prepared using a two-photon transition from the ground state 5S1/2, through an intermediate state 5P3/2 and then to the desired Rydberg state. We have studied interactions between pairs of atoms at several energy levels, using two different techniques. In the first one, we have monitored the effects of the population transfer in nD states derived from a Förster resonance. We have studied the resonance nD5/2 + nD5/2 → (n + 2)P3/2 + (n 2)F7/2 for states of 37 ≤ n ≤ 47 as a function of of the samples atomic density. For the 37D5/2 state we have also manipulated the same resonance with the application of an external electric field. Our results have shown that this is a binary process, indicated by the quadratic dependence of the transferred population in relation with the excited state. In another experiment, we have studied the interaction between nS1/2 states by monitoring, and controlling, the excitation blockade effect. Here we have shown that it is possible to control the inter-atomic interactions in a quasi-one-dimensional sample of Rydberg-atoms by varying the orientation of an external electric field. We have demonstrated that when polarizing a sample of atoms, in the 50S1/2 state with a field, it starts to interact in a similar way as classic electric-dipoles, where the interaction can be controlled by varying the orientation of the atomic dipoles. Such interaction may even be canceled when the electric dipoles are aligned at an angle of 54,7° related to the internuclear axis.

Die Verarbeitung unbekannter und visuell vertrauter Gesichter wurde mittels simultaner Messung von Elektroenzephalogramm (EEG), Magnetoenzephalogramm (MEG) und Verhaltensreaktionen untersucht. Dipollokalisationen zeigten, dass MEG und EEG bei 170 ms und 400 bis 500 ms nach Beginn von Gesichterdarbietungen Aktivierung der posterioren Gyri fusiformes (GF) abbilden. Damit konnten beide Zeitbereiche als Aktivität des fusiformen Gesichterareals interpretiert werden. In einem Primingparadigma wurde bei viermaliger Wiederholung unbekannter Gesichter ein Reaktionszeitpriming gezeigt, das für Wiederholungen mit einem Zeitabstand (Lag) von Sekunden stärker als für mehrere Minuten war. Im EEG bewirkten nur Wiederholungen mit kurzem Lag einen Wiederholungseffekt von 300 ms bis 600 ms an posterioren und zentralen Elektroden. Dieser wurde als Korrelat impliziter Gedächtnisverarbeitung von Gesichtern im GF interpretiert. Ein frontaler Wiederholungseffekt ab 700 ms wurde als Ausdruck inzidentellen Erkennens der Gesichterwiederholungen angesehen. Das MEG zeigte posterior einen Wiederholungseffekt ab 800 ms für das kurze Lag. Für das lange Lag wurden keine MEG- oder EEG-Effekte gefunden. Die Wiederholung des Primingexperimentes mit den in einem Lerntraining vertraut gewordenen Gesichtern erzeugte eine generelle Verkürzung der Reaktionszeiten, aber eine Abschwächung des Primingeffektes für das kurze Lag und einen Verlust der Abhängigkeit der Primingstärke vom Zeitabstand. Diese Veränderungen gingen im EEG mit dem Trend zur Verstärkung des posterioren Wiederholungseffektes ab 500 ms einher. Im MEG konnte für die vertrauten Gesichter ein dem EEG in Zeit und Entstehungsort analoger Wiederholungseffekt gezeigt werden. Die Ergebnisse der Untersuchung von Priming bringen Evidenz für die Existenz von Primingeffekten für unbekannte Gesichter. Sie zeigen die Abhängigkeit der Primingeffekte vom Wiederholungsabstand und die Veränderung von Primingeffekten beim Erwerb visueller Vertrautheit. / The processing of unfamiliar and visually familiar faces was examined in a simultaneous measurement of Electroencephalogram (EEG), Magnetoencephalogram (MEG) and behavioural reactions during the presentation of a priming task. Dipole modelling on the EEG and MEG data localized activity in posterior fusiform gyri around 170 ms and between 400 and 500 ms post stimulus onset. Both time ranges were interpreted as activity correlates of the fusiform face area. In the priming paradigm unfamiliar faces were repeated four times. A reaction time priming effect could be shown. This effect was stronger for a short lag (seconds) between repetitions than for minutes. In EEG, only repetitions with short lag evoked a repetition effect at posterior and central electrodes between 300 and 600 ms. This effect was interpreted as a correlate of implicit memory processes presumably generated in the fusiform gyrus. A frontal repetition effect starting around 700 ms was considered a reflection of the incidental recognition of the face repetitions. The MEG data showed a repetition effect for the short lag starting at 800 ms. No electrophysiological effects of face repetition were found for the long lag. Some months later, the same subjects were visually familiarized with the faces in three learning sessions and the priming experiment was repeated. An overall shortening of reaction times was found together with a weakening of the priming effect for the short lag and an absence of the lag’s influence on the strength of the priming effects. In the EEG data a trend for a strengthening of the posterior repetition effect from 500 ms onward emerged. The MEG data yielded a repetition effect for the familiar faces that was analogous to the EEG effect. The results of the priming task give evidence for the existence of priming effects for unfamiliar and familiar faces. They furthermore demonstrate the dependency of priming effects on the lag between repetitions and the visual familiarity of the faces.