Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Adsorption has become a key process for the removal of very low amounts of undesirable components from waters and wastewaters and in the sense for being environmental friendly as well. This work has as aim the study of some properties of scales of Corvina fish (Micropogonias furnieiri) as a new adsorbent to remove Cr(VI) from aqueous solutions. The Corvina scales were characterized by thermogravimetry, Fourier transformed infrared spectroscopy, scanning electron microscopy with energydispersive electron probe X-ray analysis, X-ray diffraction and pH of point of zero charge. The characterization results have suggested that the Corvina scales present two main structural phases, one being rich in type I collagen and one rich in apatites. Sorption studies of Cr(VI) using the batch methodology have indicated that Cr(VI) sorption increased when both initial Cr(VI) concentration in solution and temperature increase. Calorimetric measurements of scales water wetting have pointed out slightly exothermic results and degrees of wetting from 30.8 to 45.3 %. The kinetic data of Cr(VI) sorption were best fitted to the Avrami exponential model. The equilibrium data of Cr(VI) sorption were best fitted to both the Langmuir-Freundlich and the Sips models. Indirect thermodynamic determinations have indicated that the sorption of Cr(VI) is endothermic (ΔH = 31,21 kJ mol-1), spontaneous (ΔG < 0), with positive entropies (ΔS = 0,14 kJ mol-1 K-1). Calorimetric measurements have suggested that the interactions of Cr (VI) with the surface sorption sites of Corvina scales are exothermic in nature. It also was found that the presence of an anionic surfactant can increase Cr(VI) sorption on Corvina scales due to a dynamic equilibrium between monomers and micelles. The initial analysis of Cr(VI) desorption from Corvina scales has shown the release of about 30% of sorbed chromium in alkaline medium. It has been noted that the scales of Corvina fish present important characteristics to be used as a new adsorbent for removal of Cr(VI) from aqueous solutions. / A sorção tem se tornado um método muito atrativo, pois permite extrair compostos tóxicos em níveis muito baixos e não gerar subprodutos tóxicos em efluentes aquosos. O presente trabalho avaliou a utilização de escamas de peixe Corvina (Micropogonias furnieri) como um novo adsorvente para remoção do Cr(VI) de soluções aquosas. As escamas foram caracterizadas por termogravimetria, espectroscopia na região do infravermelho, microscopia eletrônica de varredura com medidas de energia dispersiva, difratometria de raios-X e determinação do pH do ponto de carga zero. Os resultados indicaram que as escamas são formadas, predominantemente, de uma fase orgânica rica em colágeno tipo I e outra rica em apatitas. Testes calorimétricos de molhação das escamas apontaram energias de molhação exotérmicas e graus de molhação entre 30,8-45,3%. Estudos cinéticos mostraram aumento da capacidade de remoção das escamas com o aumento da concentração inicial de Cr(VI) em solução e da temperatura. Estudos de cinética de sorção de Cr(VI) por batelada e por calorimetria em solução apontaram melhores ajustes matemáticos utilizando-se o modelo exponencial de Avrami. Estudos de sorção no equilíbrio indicaram melhor ajustes aos modelos de Langmuir-Freundlich e Sips. Determinações termodinâmicas indiretas indicaram que os processos de sorção são endotérmicos (ΔH = 31,21 kJ mol-1), espontâneos (ΔG < 0), e com aumento de entropia após os processos de sorção (ΔS = 0,14 kJ mol-1 K-1). Medidas calorimétricas em solução indicaram que as interações de Cr(VI) com os sítios de sorção mais externos são processos exotérmicos. A presença de surfactante aniônico na solução de Cr(VI) pode aumentar a sorção de Cr(VI) pelas escamas devido a um equilíbrio dinâmico entre monômeros e micelas. Testes iniciais de dessorção de Cr(VI) indicaram liberação de cerca de 30% do crômio sorvido, em meio básico. Observou-se que as escamas de Corvina apresentam excelentes perspectivas como um novo material para remoção de Cr(VI) de soluções aquosas.

A preocupação com o desenvolvimento sustentável tem levado a indústria e os órgãos controladores do meio ambiente a reavaliarem o emprego em larga escala de procedimentos industriais que, embora eficientes, são prejudiciais à saúde humana e ao meio ambiente. Em concordância com estas novas tendências, as indústrias de tratamento de superfícies de metais e instituições de pesquisa têm empregado grandes esforços no sentido de encontrar substitutos eficientes para procedimentos de proteção contra a corrosão que contenham íons de cromo hexavalente, os quais são muito eficientes, mas apresentam o inconveniente de não serem ambientalmente corretos devido ao caráter cancerígeno e poluente do íon Cr(VI) já reconhecido por diversas agências de proteção ambiental. Com a finalidade de aumentar a proteção contra a corrosão, em linhas industriais contínuas de eletrogalvanização por eletrodeposição, as peças produzidas são protegidas por uma camada de passivação obtida em banho de conversão contendo sais de Cr(VI) e, na maioria dos casos, não passa pelo processo de enxágue após sua produção. Neste trabalho o comportamento de corrosão do aço eletrogalvanizado protegido com camadas de passivação obtidas a partir de banhos de conversão contendo sais de Cr(III) e Co(II) ou uma emulsão de um copolímero de etileno, sem enxágue, foi avaliado por técnicas eletroquímicas, especificamente, acompanhamento do potencial de circuito aberto, curvas de polarização potenciodinâmica anódicas e catódicas, e espectroscopia de impedância eletroquímica (EIS), em soluções com diferentes concentrações de NaCl. Adicionalmente foi avaliado o comportamento de corrosão por ensaios em câmara de névoa salina, realizados de acordo com a norma ASTM B117-11. Como referência, os resultados foram comparados com aqueles apresentados por amostras protegidas por camada de passivação produzida a partir de banho contendo íons de Cr(VI). Para melhor compreender a influência da microestrutura sobre o mecanismo de corrosão, as amostras foram caracterizadas por microscopia eletrônica de varredura antes e após imersão nos diferentes eletrólitos. A análise microestrutural foi complementada por ensaios de difração de raios-X. 7 Os resultados dos ensaios eletroquímicos realizados após tempos curtos de imersão mostraram melhor desempenho para as amostras protegidas com a camada de passivação produzida a partir de banho contendo íons Cr(VI). Entretanto os ensaios de EIS após tempos mais longos de imersão nos diferentes eletrólitos ensaio, bem como os ensaios de névoa, evidenciaram que as amostras protegidas com a camada passiva obtida a partir do banho contendo íons de Cr(III) e Co(II) podem apresentar desempenho semelhante àquelas protegidas com camada de conversão de Cr(VI). Para esta condição, a análise microestrutural e o ajuste dos diagramas de EIS com circuitos equivalentes indicaram um papel importante dos produtos de corrosão no comportamento anticorrosivo das amostras protegidas com a camada de passivação de Cr(III) e Co(II). Em nenhuma das condições estudadas as amostras protegidas com o copolímero de etileno apresentaram desempenhos comparáveis aos das outras duas camadas de passivação estudadas. / Recent concerns with sustainable development have led industries and environment regulatory agencies to reassess the use at large scale of industrial procedures that, although efficient, are harmful to human health and the environment. In accordance with these new tendencies, surface treatment industries and research institutes have expended great efforts to find efficient substitutes for corrosion protection procedures that employ hexavalent chromium ions (Cr(VI)). They are very effective but have the drawback of not being environmentally friendly due to the carcinogenic and pollutant properties of Cr(VI) ions, already recognized by several environmental protection agencies. Aiming to increase the corrosion protection, in industrial continuous lines of galvanizing by electroplating, the parts produced are protected with a passivation layer obtained from a conversion bath containing Cr(VI). These parts are not rinsed after the final production step. In this work the corrosion behavior of electroplated galvanized steel protected with passivation layers from conversion baths containing Cr(III) and Co(II) ions or an ethylene copolymer emulsion was evaluated by means of electrochemical techniques, specifically, open circuit potential measurements, anodic and cathodic potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The tests were performed in sodium chloride solutions of different concentrations. Additionally, the corrosion behavior was evaluated by salt spray tests performed according the ASTM B117-11 standard. For reference, the results were compared with those presented by samples protected by passivation layers produced from conversion baths containing Cr (VI) ions. Aiming to better understand the influence of microstructure on the corrosion mechanism, the samples were characterized by scanning electron microscopy before and after immersion in the different electrolytes. Microstructure analysis was complemented by X-ray diffraction. The results of electrochemical tests performed after short immersion times showed better corrosion performance for samples protected with the passivation layer produced from conversion baths containing Cr(VI) ions. However, the EIS tests performed after longer immersion times in the different electrolytes, as well as the 9 salt spray tests, showed that samples protected with the passive layer obtained from the bath containing Cr (III) and Co (II) ions may present similar performance to those protected with the Cr (VI) conversion layer. The microstructural analysis and fitting of the EIS diagrams with equivalent circuits indicated an important role of corrosion products in the anti-corrosive performance of the samples protected with the passivation layer of Cr (III) and Co (II). In the studied conditions, the samples protected with the ethylene copolymer did not showed comparable performance to the other two passivation layers investigated in the present study.

Mon travail a porté sur la caractérisation des effecteurs toxiques et protéines d’immunité du T6SS Sci-1 d’Escherichia coli Entero-agrégatif, éléments de la lutte inter-bactérienne. Nous avons identifié en outre Tle1, un effecteur de toxine codé par ce groupe et montré que Tle1 possède des activités de phospholipase A1 et A2 requises pour détruire la cellule proie dans la compétition interbactérienne. L'auto-protection de la cellule attaquante est assurée par une lipoprotéine de membrane externe, Tli1, qui lie Tle1 dans un rapport stoechiométrique 1: 1 avec une affinité nanomolaire et inhibe son activité phospholipase. Il a été prédit que la protéine 435 provenant à partir d'un groupe de gènes T6SS1 de l'agent pathogène AIEC LF82 est une phospholipase de la famille d'effecteurs Tle3 avec une activité PLA1. Sa toxicité peut être neutralisée par la protéine d'immunité cognate 434 qui est un Tli3 putatif, en formant le complexe de protéine Tle3 - Tli3. Les deux protéines séparées et leur complexe ont ensuite été appelées protéines complexes Tle3AIEC, Tli3AIEC et Tle3AIEC - Tli3AIEC, respectivement. Afin d'étudier plus en détail le mécanisme de Tle3-AIEC et de Tli3-AIEC, nous avons réalisé l'expression, la purification, la caractérisation, la cristallisation des deux protéines et des études cristallographiques de rayons X préliminaires du complexe Tle3-AIEC/Tli3-AIEC afin de comprendre comment la protéine Tle3-AIEC reconnaît et se lie à son effecteur apparenté Tli3-AIEC et inhibe son activité. Les données préliminaires de diffraction des rayons X ont été recueillies à partir de cristaux Tle3AIEC-SeMet/Tli3AIEC à une résolution de 3,8 Å. / Here, we analyzed the Entero-aggregative Escherichia coli Sci-1 T6SS toxin effectors. We identified Tle1, a toxin effector encoded by this cluster and show that Tle1 possesses phospholipase A1 and A2 activities required for the inter-bacterial competition. Self-protection of the attacker cell is secured by an outer membrane lipoprotein, Tli1, which binds Tle1 in a 1:1 stoichiometric ratio with nanomolar affinity, and inhibits its phospholipase activity.The protein 435 from the pathogen AIEC LF82 has been predicted to be a phospholipase of the Tle3 effector family with PLA1 activity from a T6SS1 gene cluster. Its toxicity can be neutralized by the cognate immunity protein 434 that is a putative Tli3, by forming Tle3 - Tli3 protein complex. The two separated proteins and their complex were then called Tle3AIEC, Tli3AIEC and Tle3AIEC - Tli3AIEC complex proteins, respectively. In order to further investigate the related mechanism of Tle3AIEC and Tli3AIEC, we performed expression, purification, characterization, crystallization of the two proteins and preliminary X-ray crystallographic studies of the Tle3AIEC - Tli3AIEC complex in order to understand how Tle3AIEC protein recognizes and binds to its cognate Tli3AIEC effector and inhibits its activity. X-ray diffraction data were collected from selenomethionine-derivatize Tle3AIEC SeMet - Tli3AIEC crystals to a resolution of 3.8 Å.

The purpose of this study has been to explore and provide the social work field with testimonies about experienced factors of success using interviews with people who previously were not in education, employment or training (NEET). NEETs were classified into five categories to identify themes in their experienced factors of success. This process was made through thematic analysis. The experienced factors of success were thematized into major themes. The expressed themes followed the person to whom it belonged into their respective NEET-category. Categories and themes were analyzed with Bronfenbrenner’s ecological systems theory. Through this analysis we found indications that different NEET-categories have different needs. This could be an indication that categorization can shed some clarity in the NEET phenomena. Viewing NEET as categories with specific needs provides homogeneity which could accelerate the social services process of identifying and providing appropriate help. Though specific needs of individual NEET-categories need further investigation to become effective. / VI-projektet

The thesis deals with the Czechoslovakia - Vatican relationships in the 1960's with an emphasis on the 1968 Prague Spring time. It summarises the importance of the 2nd Ecumenical Council of the Vatican and demonstrates the transformation of the papacy starting with early 1960's. The core of the thesis is an analysis of the political relations between Czechoslovakia and Vatican in 1968, and the attitude of Pope Saint Paul VI. (1963-1978) to the events in Czechoslovakia, with added emphasis on the personalities of Czech and Slovak bishops, negotiations between the Church and the state, as well as the metamorphoses of the Czechoslovakia-Vatican diplomatic contacts. The diplomatic negotiations present an interesting bonus primarily from the Radio Vaticana archive, which is available, in a digital version, at the Institute for the Study of Totalitarian Regimes website. Keywords Communism; Vatican II - Second Ecumenical Council of the Vatican; Pope St. Paul VI.; Catholic Church; Vatican.

Die Verfügbarkeit von Metallen in der Geo- und Biosphäre wird durch deren chemische Form, die Speziation, bestimmt. Zur Analyse der Speziation gibt es eine Vielzahl von Techniken. Für spektroskopische Methoden sind untersuchbare Konzentrationsbereiche unter anderem durch entsprechende Detektionsgrenzen eingeschränkt. Vor allem für niedrige Konzentrationen (< 10 µM), wie sie für viele natürliche Systeme von Bedeutung sind, ist die Lumineszenzspektroskopie ein geeignetes Werkzeug. Die Zerlegung spektroskopischer Daten von komplexen Systemen stellt eine zusätzliche Herausforderung dar. Zur Extraktion spektraler Informationen individueller chemischer Spezies werden moderne mathematische Verfahren verwendet. Die so erhaltene spektroskopische Charakterisierung kann zur strukturellen und thermodynamischen Interpretation genutzt werden. In dieser Arbeit wurde die parallele Faktoranalyse (PARAFAC) zur Auswertung spektroskopischer Datensätze genutzt. Diese Technik wurde hier erstmals auf Uranyl(VI)-Systeme angewendet, wodurch eine umfassende lumineszenzspektroskopische Charakterisierung der Uranyl(VI)-Hydrolyse generiert wurde. Zusätzlich wurde der bestehende PARAFAC-Algorithmus (N-way Toolbox) erweitert. Damit wird die Zerlegung auf chemisch interpretierbare Ergebnisse beschränkt und eine direkte Extraktion thermodynamischer Daten ermöglicht. Für die mononuklearen Hydrolysespezies konnten korrigierte Komplexstabilitätskonstanten vorgeschlagen werden, wodurch entsprechende Speziationsrechnungen belastbarer werden. Die extrahierten spektralen Eigenschaften einzelner Spezies wurden anschließend sorgfältig analysiert. Dazu wurden quantenmechanische sowie semiempirische Ansätze genutzt. Neben einerValidierung der angenommenen Speziesbezeichnung wurde dadurch erstmals eine fundierte lumineszenzspektroskopische Signal-Struktur-Beziehung für die Uranyl(VI)-Hydrolyse generiert. Die entwickelten Algorithmen wurden im Rahmen der Arbeit auf komplexere Systeme des Uranyl(VI) und Europium(III) übertragen und deren Gültigkeit nachgewiesen. So konnten neue Erkenntnisse zur Lumineszenzlöschung des Uranyl(VI)-Ions und der Europium(III)-Hydrolyse gewonnen werden. Zudem wurde eine Strategie zur einfachen und akkuraten Bestimmung der Anzahl von Bindungsstellen am Beispiel des Proteins Calmodulin vorgestellt. Der aufgezeigte breite Anwendungsbereich wird zusätzlich durch die erfolgreiche Übertragung der SpecConst-Erweiterung auf andere spektroskopische Techniken (am Beispiel der UV-vis Spektroskopie) erweitert. Die vorgestellten Werkzeuge verbessern die Auswertung spektroskopischer Daten und erweitern das damit verbundene Verständnis komplexer umweltrelevanter Systeme.:Danksagung I Abkürzungen IV 1 Motivation 1 2 Einleitung und Hintergrund 4 2.1 Speziation 4 2.1.1 Hydrolyse 6 2.2 Uran 7 2.2.1 Uranyl(VI) 13 2.3 Optische Spektroskopie 14 2.3.1 Absorptionsspektroskopie 15 2.3.2 Lumineszenz 16 2.3.3 Uranyl(VI)-Lumineszenz 18 3 Material und Methoden 24 3.1 Chemikalien 24 3.2 Komplexbezeichnung 25 3.3 Probenvorbereitung 26 3.4 Absorptionsspektroskopie 27 3.5 Lumineszenzspektroskopie 27 3.5.1 Continuous Wave Spektroskopie 27 3.5.2 Zeitaufgelöste laserinduzierte Fluoreszenzspektroskopie 30 3.6 Datenauswertung - PARAFAC 34 3.7 Extrapolation auf Standardbedingungen 38 4 Ergebnisse und Diskussion 40 4.1 Methodenentwicklung 40 4.1.1 Exponentielle Einschränkung für PARAFAC - ’ExpConst’ 40 4.1.2 Speziationseinschränkung für PARAFAC - ’SpecConst’ 42 4.1.3 Spektrenzerlegung 45 4.2 Validierung der Methoden am Beispiel der Uranyl(VI)-Hydrolyse 51 4.2.1 Hydrolyse von 10−5 M Uranyl(VI) 51 4.2.2 Hydrolyse von 10−8 M Uranyl(VI) 62 4.2.3 Absorptionsspektroskopie der Uranyl(VI)-Hydrolyse 72 4.3 Übertragung der Methoden auf komplexere Uranyl(VI)-Systeme 75 4.3.1 Das Uranyl(VI)-Carbonat-System 75 4.3.2 Das Uranyl(VI)-Halogenid-System 79 4.4 Übertragung der Methoden auf Europium(III)-Systeme 86 4.4.1 Die Europium(III)-Hydrolyse 86 4.4.2 Interaktion von Europium(III) mit Calmodulin 94 5 Zusammenfassung 103 Literaturverzeichnis 106 Abbildungsverzeichnis 131 Tabellenverzeichnis 134 Publikationen im Rahmen dieser Arbeit i Konferenzbeiträge iii Eidesstattliche Erklärung iv Versicherung v

Les nanostructures de semiconducteurs II-VI ont de nombreuses applications en microélectronique, optoélectronique et photonique. Notamment, les boites quantiques II-V peuvent servir de source de photons uniques. Dans cette étude, nous nous sommes intéressés à la caractérisation chimique et structurale des nanostructures de semiconducteurs II-VI (boites quantiques (BQs) auto-organisées, nanofils II-VI et III-V …) par sonde atomique tomographique (SAT). Dans un premier temps, nous avons optimisé les conditions d’analyse des semiconducteurs III-V et II-VI par SAT. Ensuite, nous avons étudié les compositions chimiques des interfaces II-VI/III-V en montrant la formation d’un composé Ga2.7Se3 à l’interface ZnSe/GaAs et un mélange de cations (Ga, Zn) à l’interface ZnTe/InAs. Les mesures de compositions chimiques et des tailles des boites quantiques en trois dimensions par SAT ont permis de faire une corrélation avec les mesures optiques. Nous nous sommes aussi intéressés à l’étude des mécanismes de croissance des nanofils GaAs et ZnTe ainsi que des BQs (CdTe) insérés dans des nanofils ZnTe en analysant la composition chimique des catalyseurs, les BQs dans les nanofils aussi que la base des nanofils. Ces mesures montrent que les boites quantiques sont formées d’un fort mélange CdxZn1-xTe. Un scénario basé sur la diffusion de surface a été proposé pour expliquer la croissance ainsi que le mélange entre Zn/Cd pour les BQs insérées dans les nanofils. / Nanostructures of II-VI nanostructure have many applications in microelectronics, optoelectronics and photonics. For example, II -V quantum dots have shown the ability to be a source of single photons. In this work, we performed in the chemical and structural characterization of nanostructures of II-VI semiconductors (self- organized quantum dots (QDs), nanowires II-VI and III- V ...) by atom probe tomography (APT). Firstly, the analysis conditions of III-V and II- VI semiconductors by APT were optimized. Then, we studied the chemical composition of II-VI/III-V interfaces and showed the formation of a Ga2.7Se3 compound at the ZnSe/GaAs interface and the (Ga, Zn) cations mixing at the ZnTe/InAs interface. The measurements of the chemical composition and the sizes of quantum dots in three dimensions by APT allowed making a correlation with optical measurements. We studied also growth mechanisms of GaAs, ZnTe nanowire and the CdTe QDs inserted in ZnTe nanowires by analyzing the chemical composition of the catalysts QDs and nanowires basis. These measurements show that the quantum dots are formed of a strong mixing of CdxZn1-xTe. A scenario based on surface diffusion has been proposed to explain the growth and the mixing between Zn/Cd for the QDs.

The chemical contamination of natural waters is a global problem with a worldwide impact. Considering the relevance of this problem, this thesis is intended, on one hand, to develop different separation/preconcentration techniques based on membranes ability to permeate anions for the transport of toxic oxyanions of chromium(VI) and arsenic contained in aqueous matrices. In particular, we have investigated supported liquid membranes and polymer inclusion membranes, both of which contain the commercial quaternary ammonium salt Aliquat 336 as a carrier, as well as commercial anion exchange membranes. On the other hand, we have focused on the development of chemical sensors to facilitate the monitoring of several metals from different aqueous matrices. Thus, a selective optical sensor for Cr(VI) based on polymeric membranes containing Aliquat 336 as an ionophore has been designed. Additionally, mercury-based screen-printed electrodes have been evaluated for for cadmium, lead, copper and zinc detection. / La contaminació química de les aigües naturals és un problema global amb repercussió a nivell mundial. Donada la rellevància que té aquesta problemàtica, en la present tesi s’han desenvolupat d’una banda tècniques de separació/preconcentració basades en diferents sistemes de membrana en què el mecanisme de transport proposat és un bescanvi aniònic per als oxoanions tòxics de crom(VI) i arsènic presents en matrius aquoses. Concretament, s’ha treballat amb membranes líquides suportades que contenien el portador comercial Aliquat 336, membranes d’inclusió polimèriques amb el mateix portador i membranes de bescanvi aniònic comercials. D’altra banda, s’ha treballat en el desenvolupament de diferents sensors químics per monitoritzar diversos metalls presents en matrius aquoses. Així, s’ha dissenyat un sistema de sensor òptic selectiu a Cr(VI) basat en membranes polimèriques utilitzant també el portador Aliquat 336 i s’ha desenvolupat un sistema de monitorització per plom, coure, cadmi i zinc basat en microelèctrodes serigrafiats modificats amb mercuri.

Carte du bailliage en fichier complémentaire. / Le bailli d’Amiens, sous Philippe VI (1328-1350), intervenait fréquemment dans les principautés du Nord de la France que sont les comtés d’Artois, de Ponthieu et de Flandre. L’étendue de son ressort, ainsi que son emplacement stratégique, en firent une sentinelle du gouvernement central et un ardent défenseur des droits du roi. Agissant parfois avec trop de zèle, entrant ce faisant en conflit avec les juridictions urbaines, d’Église et seigneuriales, cet officier royal constituait un lien important entre les justiciables de sa circonscription et l’autorité royale des actes et lettres de laquelle il devait veiller à la transmission et l’exécution. De son côté, la cour du roi sembla approuver le travail du bailli, n’intervenant que rarement en réaction aux excès commis par ce dernier et confirmant l’essentiel des sentences du bailli jugées en appel. / The bailiff of Amiens, under Philip VI (1328-1350), frequently intervened in the principalities of northern France that are the counties of Artois, Ponthieu and Flanders. The extent of its jurisdiction, and its strategic location made him a sentinel of the central government and a staunch advocate of the king’s rights. Sometimes acting too zealously, thereby entering into conflict with urban jurisdictions, and stately church, this royal officer was an important link between citizens of his district and the royal authority of the acts and letters which he had to ensure transmission and execution. For its part, the king's court seemed to endorse the work of the bailiff, intervening only rarely in response to the excesses committed by the latter and confirming the main awards of the Bailiff considered on appeal.

Halbleiter Quantenpunkte (QP) standen in den letzten Jahren im Mittelpunkt vieler Forschungsaktivitäten im Bezug auf mögliche Anwendungen im Bereich der Quanteninformationsverarbeitung. Durch das dreidimensional Confinement sind nur diskrete, energetisch stark separierte Zustände in einem QP möglich. Damit sind phasenzerstörende Streuprozesse unwahrscheinlicher und man kann Dekohärenzzeiten erwarten, die nur durch die Lebensdauer der Zustände limitiert sind. Materialbasis dieser Arbeit sind CdSe QP in einer ZnSe Barriere. In dieser Arbeit werden zwei Arten von Kohärenzphenomänen, die das zeitliche Verhalten solcher Quantensysteme beschreiben, mittels optischer Methoden untersucht. Im Falle optischer Kohärenz wechselwirkt ein angeregter Zustand, der strahlend mit einem Grundzustand verbunden ist, mit einem externen elektro-magnetischen Feld. Mittels phasensynchronisierter kohärenter Kontrolle werden biexzitonische und auch erste angeregte Zustände in einzelnen QP untersucht. Im Fall des angeregten Zustandes findet man optische Dephasierungszeiten unterhalb von 10 ps. Für das Biexziton kann nur eine untere Grenze bestimmt werden, die auf einer 10 ps Zeitskala liegt. Das zweite Phenomän ist die Quantenkohärenz (QK), die das Phasengedächtnis zweier Zustände im selben QP vergleicht. In dieser Arbeit wird die QK durch die Analyse von Quantenschwebungen in der Emission des Grundzustandsexzitons in einem einzelnen QP untersucht. Es wurde gefunden, dass es keine messbare Dekohärenz der beiden Unterzustände des Grundzustandsexzitons im Rahmen der strahlenden Lebensdauer von circa 300 ps gibt. Die dritte Gruppe von Experimenten beschäftigt sich mit der longitudinalen Spinrelaxationszeit einzelner Ladungsträger. Die verwendeten Proben ermöglichen den direkten Zugang zur Spindynamik einzelner Löcher. Die Experimente in der Spektral- als auch in der Zeitdomäne lieferten Spinrelaxationszeiten für Löcher von knapp 10 ns. / Semiconductor quantum dots (QD) have attracted considerable interest during the past years as possible candidates for quantum information processing. Due to the confinement potential in such structures, the density of states in a single QD is discrete. If the states are well separated in energy the coupling to the environment is expected to be smaller, implying that coherence is maintained during the exciton lifetime. In the present work CdSe in ZnSe QDs are used. Two kinds of coherence phenomena, reflecting the time evolution of such a quantum system, are studied by use of optical methods. In case of optical coherence, an excited state which is radiatively coupled to a ground state interacts with an external electro-magnetic field. The experimental technique of temporal coherent control is applied via a two photon process on the biexciton state and also by a single photon process on the excited state in a single QD. As a result optical coherence times below 10 ps are found for the excited state, while for the biexciton only a lower limit on a 10 ps timescale was elaborated. The second phenomena is quantum coherence and describes the phase memory between two states in the same QD. It is studied in this work by the analysis of the observed quantum beats in the time resolved photoluminescence emission (PL) of the ground state exciton in a single QD. As a result it was found that there is no measurable decoherence between the two substates of the ground state exciton during the exciton lifetime of about 300 ps. In a third group of experiments the longitudinal spin relaxation time is investigated on a single carrier level. The used QD sample contains charged QDs with resident electrons, which provide direct access to the separate spin dynamic of the holes. Different experiments carried out, yielding a longitudinal spin relaxation time for a single hole on a 10 ns timescale.